COMPRESSOR SYSTEM AND REFRIGERATION DEVICE

Description

TECHNICAL FIELD

The present disclosure relates to a compressor system and a refrigeration apparatus.

BACKGROUND ART

PTL 1 discloses a failure sign detector for an air conditioner including a compressor including a motor, and a drive device configured to output three-phase current to the motor. The failure sign detector detects a sign of failure of the air conditioner, for example, when solid contact in which metal parts are in direct contact with each other occurs on a sliding portion of the compressor due to a shortage of lubricating oil, frictional resistance increases to generate frictional heat, and the metal parts adhere to each other to stop the compressor (a failure occurs on the air conditioner). Since the output torque of the motor increases when the sliding portion of the compressor is damaged and the frictional resistance increases, and the q-axis current of the motor, which is hardly affected by electric noise, fluctuates substantially like the output torque of the motor, the failure sign detector can accurately detect a sign of failure of the air conditioner by analyzing the q-axis current of the motor.

CITATION LIST

Patent Literature

• • PTL 1: Japanese Patent No. 6173530

SUMMARY

A first aspect of the present disclosure provides a compressor system including a compressor including a motor, a compression section having a compression chamber configured to suck and compress a fluid, a drive shaft coupled to the motor and configured to drive the compression section, and a bearing supporting the drive shaft, lubricating oil being supplied from a common oil supply source to the compression section and to a sliding portion of the drive shaft and the bearing; and a prediction device configured to predict a failure of the bearing and the drive shaft of the compressor. The prediction device includes a failure prediction unit configured to predict the failure of the bearing and the drive shaft based on a change in an index indicating deterioration of sealability of the compression chamber.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a piping system diagram illustrating a general configuration of an air conditioner according to Embodiment 1.

FIG. 2 is a schematic configuration diagram illustrating a compressor system according to Embodiment 1 and a system through which power is supplied to a compressor.

FIG. 3 is a vertical sectional view of a compressor (scroll compressor) according to Embodiment 1.

FIG. 4 is a vertical sectional view illustrating an upper portion of a compressor according to Embodiment 2.

FIG. 5 is a PV diagram presenting a change in state of the refrigerant in a compression chamber of the compressor according to Embodiment 2.

FIG. 6 is a schematic configuration diagram illustrating a compressor system according to Embodiment 5 and a system through which power is supplied to a compressor.

FIG. 7 is a piping system diagram illustrating a general configuration of an air conditioner according to Embodiment 6.

FIG. 8 is a schematic configuration diagram illustrating a compressor system according to Embodiment 7 and a system through which power is supplied to a compressor.

FIG. 9 is a graph presenting a temporal change of the primary component of the driving current of a motor in the compressor according to Embodiment 7.

FIG. 10 is a schematic configuration diagram illustrating a compressor system according to Embodiment 9 and a system through which power is supplied to a compressor.

FIG. 11 is a schematic configuration diagram illustrating a compressor system according to Modification 2 of Embodiment 9 and a system through which power is supplied to a compressor.

FIG. 12 is a vertical sectional view of a compressor (scroll compressor) according to Embodiment 12.

FIG. 13 is a vertical sectional view of a compressor (scroll compressor) according to Embodiment 13.

DESCRIPTION OF EMBODIMENTS

Embodiment 1

An air conditioner (10) according to Embodiment 1 is a refrigeration apparatus including a compressor system (40) and a refrigerant circuit (30).

—Air Conditioner—

<General Configuration of Air Conditioner>

As illustrated in FIG. 1, the air conditioner (10) includes an outdoor unit (11) and an indoor unit (13). The outdoor unit (11) houses an outdoor circuit (31). The indoor unit (13) houses an indoor circuit (35). The outdoor circuit (31) and the indoor circuit (35) are connected together via a liquid-side connection pipe (37) and a gas-side connection pipe (38) to constitute the refrigerant circuit (30).

<Refrigerant Circuit>

The outdoor circuit (31) is provided with a compressor (50), a four-way switching valve (32), an outdoor heat exchanger (33), and an expansion valve (34). In the outdoor circuit (31), the compressor (50) has a discharge pipe (53) connected to a first port (P1) of the four-way switching valve (32), and a suction pipe (52) connected to a second port (P2) of the four-way switching valve (32). The outdoor heat exchanger (33) has its gas-side end connected to a third port (P3) of the four-way switching valve (32), and has its liquid-side end connected to one end of the expansion valve (34). A fourth port (P4) of the four-way switching valve (32) is connected to one end of the gas-side connection pipe (38). The other end of the expansion valve (34) is connected to one end of the liquid-side connection pipe (37).

The compressor (50) is a hermetic scroll compressor. The compressor (50) constitutes the compressor system (40) together with a main controller (prediction device) (21), which will be described later. Details of the compressor (50) will be described later. The outdoor heat exchanger (33) is a heat exchanger that allows heat exchange between a refrigerant in the refrigerant circuit (30) and outdoor air. The expansion valve (34) is a so-called electronic expansion valve. The four-way switching valve (32) is a switching valve having the four ports (P1 to P4). The four-way switching valve (32) is configured to switch between a first state in which the first port (P1) communicates with the third port (P3) and the second port (P2) communicates with the fourth port (P4) (indicated by solid curves in FIG. 1), and a second state in which the first port (P1) communicates with the fourth port (P4) and the second port (P2) communicates with the third port (P3) (indicated by broken curves in FIG. 1).

The outdoor circuit (31) is further provided with a suction pressure sensor (26) and a discharge pressure sensor (27). The suction pressure sensor (26) is connected to the pipe connecting the suction pipe (52) of the compressor (50) and the second port (P2) of the four-way switching valve (32) to detect the pressure of the refrigerant to be sucked into the compressor (50). The discharge pressure sensor (27) is connected to the pipe connecting the discharge pipe (53) of the compressor (50) and the first port (P1) of the four-way switching valve (32) to detect the pressure of the refrigerant discharged from the compressor (50).

The indoor circuit (35) is provided with an indoor heat exchanger (36). The indoor circuit (35) has its liquid-side end connected to the other end of the liquid-side connection pipe (37), and has its gas-side end connected to the other end of the gas-side connection pipe (38). The indoor heat exchanger (36) is a heat exchanger that allows heat exchange between the refrigerant in the refrigerant circuit (30) and indoor air.

<Outdoor Unit and Motor Drive Device>

As illustrated in FIG. 1, the outdoor unit (11) is provided with, in addition to the outdoor circuit (31), an outdoor fan (12) and the main controller (21). The outdoor fan (12) is located near the outdoor heat exchanger (33), and supplies outdoor air to the outdoor heat exchanger (33). The main controller (21) is configured to control components of the outdoor unit (11). The main controller (21) will be described later.

As illustrated in FIG. 2, the outdoor unit (11) is provided with a motor drive device (45). The motor drive device (45) is configured to change the frequency of alternating current. The motor drive device (45) has its input electrically connected to a commercial power source (alternating-current power source) (47), and has its output electrically connected to a motor (55) of the compressor (50). The motor drive device (45) includes a converter, a direct-current unit, and an inverter, converts the power supplied from the commercial power source (47) into output alternating-current power (three-phase alternating-current power) having a predetermined frequency and voltage, and supplies the output alternating-current power to the motor (55). Changing the frequency of the output alternating-current power of the motor drive device (45) (hereinafter, merely referred to as “output frequency”) causes a change in the rotational speed of the compressor (50). As a result, the operating capacity of the compressor (50) changes.

<Indoor Unit and Remote Control Unit>

As illustrated in FIG. 1, the indoor unit is provided with an indoor fan (14) and an auxiliary controller (24). The indoor fan (14) is located near the indoor heat exchanger (36), and supplies indoor air to the indoor heat exchanger (36). The auxiliary controller (24) is configured to control components of the indoor unit (13).

The auxiliary controller (24) is connected to a remote control unit (15) so as to be capable of communicating with the remote control unit (15). The remote control unit (15) includes a display (16), and an operation button (17) operable by a user. The display (16) is a liquid crystal display. The display displays information indicating the operating state of the air conditioner (10) (e.g., the set temperature).

<Operation of Air Conditioner>

The air conditioner (10) selectively performs cooling operation and heating operation.

In the cooling operation, the main controller (21) sets the four-way switching valve (32) in the first state (the state indicated by the solid curves in FIG. 1), and adjusts the operating capacity of the compressor (50) and the opening degree of the expansion valve (34). The refrigerant discharged from the compressor (50) dissipates heat to outdoor air in the outdoor heat exchanger (33) to condense. Then, the condensed refrigerant expands while passing through the expansion valve (34). The refrigerant that has passed through the expansion valve (34) flows through the liquid-side connection pipe (37) into the indoor circuit (35), and absorbs heat from indoor air in the indoor heat exchanger (36) to evaporate. Then, the refrigerant flows through the gas-side connection pipe (38) into the outdoor circuit (31), and is sucked into the compressor (50) and is compressed. The indoor unit (13) blows the air cooled in the indoor heat exchanger (36) into an indoor space.

In the heating operation, the main controller (21) sets the four-way switching valve (32) in the second state (the state indicated by the broken curves in FIG. 1), and adjusts the operating capacity of the compressor (50) and the opening degree of the expansion valve (34). The refrigerant discharged from the compressor (50) flows through the gas-side connection pipe (38) into the indoor circuit (35), and dissipates heat to indoor air in the indoor heat exchanger (36) to condense. Then, the refrigerant flows through the liquid-side connection pipe (37) into the outdoor circuit (31), and expands while passing through the expansion valve (34). The refrigerant that has passed through the expansion valve (34) absorbs heat from outdoor air in the outdoor heat exchanger (33) to evaporate. Then, the evaporated refrigerant is sucked into the compressor (50) and is compressed. The indoor unit (13) blows the air heated in the indoor heat exchanger (36) into the indoor space.

—Compressor—

As illustrated in FIG. 3, the compressor (50) is a hermetic scroll compressor. The compressor (50) includes the motor (55), a compressor mechanism section (100), an upper shaft support (65), a lower shaft support (90), and a casing (51). The motor (55), the compressor mechanism section (100), the upper shaft support (65), and the lower shaft support (90) are housed in the casing (51).

<Casing>

The casing (51) is a cylindrical closed container with both ends closed. The casing (51) is arranged such that its axial direction coincides with a vertical direction. A compression section (60), the upper shaft support (65), the motor (55), and the lower shaft support (90) are sequentially arranged in the internal space of the casing (51) from top to bottom. An oil reservoir (95) is formed in a bottom portion of the casing (51). Lubricating oil (refrigerating machine oil) is stored in the oil reservoir (95).

The casing (51) includes the suction pipe (52) and the discharge pipe (53). The suction pipe (52) passes through the top of the casing (51), and is connected to the compression section (60). The suction pipe (52) guides the low-pressure refrigerant of the refrigerant circuit (30) to the compression section (60). The discharge pipe (53) passes through the barrel of the casing (51), and opens in the internal space of the casing (51) (the space below the lower shaft support (90)). The discharge pipe (53) guides, to the outside of the compressor (50), the high-pressure refrigerant that has been discharged from a compression chamber (61) and then guided to the space below the lower shaft support (90) of the casing (51). With such a configuration, the pressure of the high-pressure refrigerant discharged from the compression chamber (61) acts on the space (including the oil reservoir (95)) below the lower shaft support (90) of the casing (51).

<Motor>

The motor (55) includes a stator (56) and a rotor (57). The stator (56) is fixed to the barrel of the casing (51). The rotor (57) is located inside the stator (56). A drive shaft (80) is inserted through the rotor (57).

<Upper Shaft Support>

The upper shaft support (65) includes a main body (66) and a main bearing portion (68). The main body (66) is formed in a thick disk-like shape and fixed to the casing (51). A crank chamber (67) is formed in a center portion of the main body (66). The crank chamber (67) is a cylindrical recess that opens in a front surface (upper surface in FIG. 3) of the main body (66). The main bearing portion (68) is formed in a cylindrical shape protruding from a back surface (lower surface in FIG. 3) of the main body (66), and is located at the center portion of the main body (66). The main bearing portion (68) has a through hole through which the drive shaft (80) is inserted. A second bearing (69), which will be described later, is fitted into the through hole.

<Lower Shaft Support>

The lower shaft support (90) includes one auxiliary bearing portion (91) and three legs (92). The auxiliary bearing portion (91) is formed in a thick cylindrical shape. A third bearing (93), which will be described later, is fitted into the auxiliary bearing portion (91). The legs (92) extend radially from the auxiliary bearing portion (91). The protruding ends of the legs (92) of the lower shaft support (90) are fixed to the barrel of the casing (51).

<Compressor Mechanism Section>

The compressor mechanism section (100) includes the compression section (60), the drive shaft (80), first to third bearings (79, 69, 93), and an oil supply passage (87). The various sensors attached to the components of the compressor mechanism section (100) are not included in the components of the compressor mechanism section (100).

(Compression Section)

The compression section (60) is a scroll fluid machine. The compression section (60) includes a fixed scroll (70) and an orbiting scroll (75). Wraps of the fixed scroll (70) and the orbiting scroll (75) mesh with each other to form a plurality of compression chambers (61).

The fixed scroll (70) includes a fixed end plate (71), a fixed wrap (72), and an outer peripheral wall portion (73). The fixed end plate (71) is a relatively thick, flat plate-shaped portion located at an upper portion of the fixed scroll (70). The fixed wrap (72) is formed in a spiral wall shape, and protrudes from a front surface (lower surface in FIG. 3) of the fixed end plate (71). The outer peripheral wall portion (73) surrounds the outer periphery of the fixed wrap (72), and protrudes from the front surface of the fixed end plate (71). The outer peripheral wall portion (73) is fixed to the upper shaft support (65) fixed to the casing (51). A suction port (sp) is formed in the outer peripheral wall portion (73). The suction pipe (52) is inserted into the suction port (sp). A discharge port (dp) is formed in the fixed end plate (71), and a temperature sensor (111) is embedded in the vicinity of the discharge port (dp) in order to detect the temperature of discharge gas. The temperature sensor (111) detects the temperature of the discharge gas, converts the detected temperature into an electric signal, and outputs the electric signal to the main controller (21).

The orbiting scroll (75) includes an orbiting end plate (76), an orbiting wrap (77), and a boss (78). The orbiting end plate (76) is formed in a substantially circular flat-plate shape. The orbiting wrap (77) is formed in a spiral wall shape, and protrudes from a front surface (upper surface in FIG. 3) of the orbiting end plate (76). The boss (78) is formed in a cylindrical shape protruding from a back surface (lower surface in FIG. 3) of the orbiting end plate (76), and is located at a center portion of the orbiting end plate (76). A first bearing (79), which will be described later, is fitted into the boss (78).

(Drive Shaft)

The drive shaft (80) includes a main shaft portion (81) and an eccentric shaft portion (85). The main shaft portion (81) includes a main journal portion (82), an auxiliary journal portion (83), and an intermediate shaft portion (84). The drive shaft (80) is arranged in a posture in which the eccentric shaft portion (85) is located above the main shaft portion (81).

The main journal portion (82), the intermediate shaft portion (84), and the auxiliary journal portion (83) are sequentially arranged from one end to the other end of the main shaft portion (81). The main journal portion (82), the intermediate shaft portion (84), and the auxiliary journal portion (83) are each formed in a columnar shape, and are coaxial with one another. In the main shaft portion (81) according to this embodiment, the main journal portion (82) has a larger diameter than the intermediate shaft portion (84), and the auxiliary journal portion (83) has a smaller diameter than the intermediate shaft portion (84). The main shaft portion (81) according to this embodiment has upper and lower portions respectively provided with the main journal portion (82) and the auxiliary journal portion (83).

The main journal portion (82) is inserted through the inside of the second bearing (69) fitted into the main bearing portion (68) of the upper shaft support (65), and is supported by the second bearing (69). The auxiliary journal portion (83) is inserted through the inside of the third bearing (93) fitted into the auxiliary bearing portion (91) of the lower shaft support (90), and is supported by the third bearing (93). The intermediate shaft portion (84) is inserted through the inside of the rotor (57) of the motor (55), and is fixed to the rotor (57).

The eccentric shaft portion (85) is formed in a relatively short shaft-like shape, and protrudes from an end face of the main journal portion (82). The drive shaft (80) according to this embodiment has its eccentric shaft portion (85) located near the upper end thereof. A shaft center of the eccentric shaft portion (85) is substantially parallel to that of the main shaft portion (81), and is eccentric with respect to the shaft center of the main shaft portion (81). The eccentric shaft portion (85) is inserted through the inside of the first bearing (79) fitted into the boss (78) of the orbiting scroll (75), and is supported by the first bearing (79).

(Bearing)

Each of the first to third bearings (79, 69, 93) is a sliding bearing that is formed in a cylindrical shape and supports the drive shaft (80).

The first bearing (79) is fitted inside the boss (78) of the orbiting scroll (75). The eccentric shaft portion (85) of the drive shaft (80) is inserted into the first bearing (79), and the first bearing (79) supports the eccentric shaft portion (85) of the drive shaft (80).

The second bearing (69) is fitted inside the main bearing portion (68) of the upper shaft support (65). The main journal portion (82) of the drive shaft (80) is inserted into the second bearing (69), and the second bearing (69) supports the main journal portion (82) of the drive shaft (80).

The third bearing (93) is fitted inside the auxiliary bearing portion (91) of the lower shaft support (90). The auxiliary journal portion (83) of the drive shaft (80) is inserted into the third bearing (93), and the third bearing (93) supports the auxiliary journal portion (83) of the drive shaft (80).

Although the details will be described later, in Embodiment 1, the first to third bearings (79, 69, 93), together with the drive shaft (80), are target portions for which a failure is predicted by a failure prediction unit (23) which will be described later.

(Oil Supply Passage)

The oil supply passage (87) is a passage through which the lubricating oil (refrigerating machine oil) stored in the oil reservoir (95) formed in the bottom portion of the casing (51) is supplied to sliding portions. The oil supply passage (87) includes a main oil supply passage (88) and an auxiliary oil supply passage (89).

The main oil supply passage (88) is formed in the drive shaft (80). The main oil supply passage (88) includes a main passage extending axially from one axial end (lower end in FIG. 3) to the other axial end (upper end in FIG. 3) of the drive shaft (80), and branch passages branching from the main passage toward a sliding portion of the drive shaft (80) with the second bearing (69), a sliding portion of the drive shaft (80) with the third bearing (93), and a sliding portion of the drive shaft (80) with the first bearing (79). The main oil supply passage (88) guides the lubricating oil (refrigerating machine oil) stored in the oil reservoir (95) to the sliding portions of the drive shaft (80) and the first to third bearings (79, 69, 93). That is, the main oil supply passage (88) is an oil supply passage that guides the lubricating oil in the oil reservoir (95) to the sliding portions of the drive shaft (80) and the bearings (79, 69, 93).

The auxiliary oil supply passage (89) is formed so as to extend over the upper shaft support (65) and the fixed scroll (70), and guides the lubricating oil stored in the crank chamber (67) to the compression section (60) (the gap between the fixed scroll (70) and the orbiting scroll (75)). The auxiliary oil supply passage (89) is formed such that one end thereof opens in the crank chamber (67) and the other end thereof opens in a gap between the outer peripheral wall portion (73) of the fixed scroll (70) and the orbiting end plate (76) of the orbiting scroll (75). The crank chamber (67) stores the lubricating oil which has been guided from the oil reservoir (95) via the main oil supply passage (88) to the sliding portion of the drive shaft (80) and the first bearing (79), has lubricated the sliding portion, and then has flowed out. Thus, the auxiliary oil supply passage (89) guides the lubricating oil, which has lubricated the sliding portion of the drive shaft (80) and the first bearing (79), from the crank chamber (67) to the compression section (60). The lubricating oil guided to the compression section (60) seals the gap between the fixed scroll (70) and the orbiting scroll (75) (seals the compression chamber (61)). That is, the auxiliary oil supply passage (89) is an oil supply passage that guides the lubricating oil in the oil reservoir (95) to the compression section (60), and guides the lubricating oil, which has been supplied from the oil reservoir (95) to the sliding portion of the drive shaft (80) and the first bearing (79) via the main oil supply passage (88) and has flowed out to the crank chamber (67), to the compression section (60).

With such a configuration, in Embodiment 1, first, the lubricating oil in the oil reservoir (95) on which the pressure (high pressure) of the refrigerant discharged from the compression chamber (61) acts is distributed and supplied to the sliding portions of the drive shaft (80) and the first to third bearings (79, 69, 93) via the main oil supply passage (88). The lubricating oil remaining after lubricating the sliding portion of the drive shaft (80) and the first bearing (79) is stored in the crank chamber (67). The lubricating oil stored in the crank chamber (67) is supplied to the compression section (60) (the gap between the fixed scroll (70) and the orbiting scroll (75)) via the auxiliary oil supply passage (89). In other words, in Embodiment 1, the oil supply passage (87) is configured to supply the lubricating oil in the oil reservoir (95) to the sliding portions of the drive shaft (80) and the first to third bearings (79, 69, 93) earlier than to the compression section (60). With such a configuration, in the compressor (50), when the amount of the lubricating oil in the oil reservoir (95) decreases, poor sealing due to a decrease in the amount of the lubricating oil for sealing the compression chamber (61) occurs before poor lubrication occurs on the sliding portions of the drive shaft (80) and the first to third bearings (79, 69, 93).

—Control System—

In the air conditioner (10) according to this embodiment, the main controller (21) of the outdoor unit (11) and the auxiliary controller (24) of the indoor unit (13) are connected to each other through a wire to constitute a control system (20).

Although not illustrated, the main controller (21) and the auxiliary controller (24) each include a CPU that executes a control program, and a memory that stores the control program, and data and other elements necessary for executing the control program.

As described above, the main controller (21) is configured to control components of the outdoor unit (11). For example, the main controller (21) adjusts the rotational speed of the outdoor fan (12) and the opening degree of the expansion valve (34), and operates the four-way switching valve (32). As illustrated in FIG. 2, the main controller (21) includes a capacity control unit (22) and a failure prediction unit (23). The capacity control unit (22) and the failure prediction unit (23) will be described later.

As described above, the auxiliary controller (24) is configured to control components of the indoor unit (13). For example, the auxiliary controller (24) adjusts the rotational speed of the outdoor fan (12) and the opening degree of the expansion valve (34), and operates the four-way switching valve (32). The auxiliary controller (24) adjusts the rotational speed of the indoor fan (14).

—Capacity Control Unit—

The capacity control unit (22) is configured to adjust the operating capacity of the compressor (50) so that the air conditioner (10) demonstrates the air conditioning capacity commensurate with the air conditioning load in the indoor space.

When the air conditioning capacity of the air conditioner (10) is low with respect to the air conditioning load in the indoor space, the capacity control unit (22) outputs, to the motor drive device (45), an instruction signal for increasing the output frequency of the motor drive device (45). Increasing the output frequency of the motor drive device (45) causes an increase in the rotational speed of the compressor (50). As a result, the operating capacity of the compressor (50) increases, and the air conditioning capacity of the air conditioner (10) increases.

During the cooling operation, for example, when the detection value of the suction pressure sensor (26) is above a target value of the low pressure of the refrigeration cycle, the capacity control unit (22) determines that the air conditioning capacity of the air conditioner (10) is low with respect to the air conditioning load in the indoor space. On the other hand, during the heating operation, for example, when the detection value of the discharge pressure sensor (27) is below a target value of the high pressure of the refrigeration cycle, the capacity control unit (22) determines that the air conditioning capacity of the air conditioner (10) is low with respect to the air conditioning load in the indoor space.

When the air conditioning capacity of the air conditioner (10) is high with respect to the air conditioning load in the indoor space, the capacity control unit (22) outputs, to the motor drive device (45), an instruction signal for reducing the output frequency of the motor drive device (45). Reducing the output frequency of the motor drive device (45) causes a decrease in the rotational speed of the compressor (50). As a result, the operating capacity of the compressor (50) decreases, and the air conditioning capacity of the air conditioner (10) decreases.

During the cooling operation, for example, when the detection value of the suction pressure sensor (26) is below the target value of the low pressure of the refrigeration cycle, the capacity control unit (22) determines that the air conditioning capacity of the air conditioner (10) is high with respect to the air conditioning load in the indoor space. On the other hand, during the heating operation, for example, when the detection value of the discharge pressure sensor (27) is above the target value of the high pressure of the refrigeration cycle, the capacity control unit (22) determines that the air conditioning capacity of the air conditioner (10) is high with respect to the air conditioning load in the indoor space.

—Failure Prediction Unit—

The failure prediction unit (23) is configured to predict a failure by detecting a sign of failure of the drive shaft (80) and the first to third bearings (79, 69, 93) based on the detection value (i.e., discharge gas temperature Tdp) of the temperature sensor (111) embedded in the compression section (60). Specifically, the failure prediction unit (23) repeatedly performs a determination operation of determining whether a predictive sign condition is satisfied every predetermined period (e.g., every 30 seconds). The predictive sign condition is a condition indicating that there is a predictive sign of failure of the drive shaft (80) and the first to third bearings (79, 69, 93). When the predictive sign condition is satisfied, the failure prediction unit (23) performs an avoidance operation of avoiding a failure of the drive shaft (80) and the first to third bearings (79, 69, 93).

<Determination Operation>

A determination operation of the failure prediction unit (23) will be described below. In the failure prediction unit (23) according to this embodiment, the predictive sign condition is a condition that a temperature difference ΔTdp (Tdp−Tn) between a discharge gas temperature Tdp (the detection value of the temperature sensor (111)) and a predetermined normal value Tn is greater than or equal to a determination reference value Tb (ΔTdp≥Tb).

First, the failure prediction unit (23) calculates the temperature difference ΔTdp between the discharge gas temperature Tdp and the predetermined normal value Tn. The normal value Tn is a discharge gas temperature in a normal state in which poor lubrication does not occur on each sliding portion of the compressor (50), and the failure prediction unit (23) stores a reference value as the normal value Tn. The failure prediction unit (23) calculates the temperature difference ΔTdp by subtracting the normal value Tn from the discharge gas temperature Tdp. For example, the normal value Tn may be a value determined in advance for each type of the compressor (50). For example, a test operation may be performed after installation of the compressor system (40), the discharge gas temperature may be measured in the normal state in which poor lubrication does not occur on each sliding portion of the compressor (50), and the measured value may be used as the normal value Tn. The normal value Tn is determined for each of operation conditions of the compressor (50) composed of the number of revolutions, the high pressure, and the low pressure.

Next, the failure prediction unit (23) compares the calculated temperature difference ΔTdp with the determination reference value Tb. The failure prediction unit (23) stores a reference value as the determination reference value Tb. When the temperature difference ΔTdp is greater than or equal to the determination reference value Tb (ATdp≥Tb), the failure prediction unit (23) determines that the predictive sign condition is satisfied. That is, the failure prediction unit (23) according to this embodiment determines that the predictive sign condition is satisfied when the temperature difference ΔTdp becomes greater than or equal to the determination reference value Tb for the first time.

As described above, the main controller (prediction device) (21) according to this embodiment includes the failure prediction unit (23) that determines whether a predetermined predictive sign condition indicating that there is a predictive sign of failure of the drive shaft (80) and the first to third bearings (79, 69, 93) is satisfied. The failure prediction unit (23) measures the discharge gas temperature Tdp, and determines whether the predictive sign condition is satisfied (the presence of a predictive sign of failure of the drive shaft (80) and the first to third bearings (79, 69, 93)) based on the discharge gas temperature Tdp. In Embodiment 1, the discharge gas temperature Tdp (an index indicating the operating state of the compression section (60)) is used for the predictive sign condition for the following reason.

In the compressor (50), when the amount of oil or the concentration of the lubricating oil in the oil reservoir (95) decreases, the lubricating state in each sliding portion of the compressor (50) to which the lubricating oil in the oil reservoir (95) is supplied via the oil supply passage (87) shifts from fluid lubrication to mixed lubrication or boundary lubrication. As a result, the drive shaft (80) and the first to third bearings (79, 69, 93) are brought into contact with each other and worn, which leads to seizure or the like, and then a failure may occur on the drive shaft (80) and the first to third bearings (79, 69, 93) (brought into an inoperable state). On the other hand, in the compression section (60), before the lubricating state in each sliding portion shifts from the fluid lubrication to the mixed lubrication or the boundary lubrication, the amount of the lubricating oil for sealing the compression chamber (61) decreases. When the amount of the lubricating oil for sealing the compression chamber (61) decreases, the amount of heat transferred from the refrigerant to the lubricating oil decreases, and the leaked refrigerant is re-compressed. Thus, the temperature of the discharge refrigerant increases as compared to the normal state (the normal state in which poor lubrication does not occur on each sliding portion of the compressor (50)), and the discharge gas temperature Tdp also increases as compared to the normal state. In Embodiment 1, attention is paid to the discharge gas temperature Tdp, which increases in conjunction with poor sealing due to a decrease in the amount of the lubricating oil for sealing the compression chamber (61), and the discharge gas temperature Tdp is used to determine the presence of a predictive sign of failure of the drive shaft (80) and the first to third bearings (79, 69, 93). Thus, it is possible to detect a sign of failure of the drive shaft (80) and the first to third bearings (79, 69, 93) after the amount of the oil in the oil reservoir (95) decreases, which causes a failure of the drive shaft (80) and the first to third bearings (79, 69, 93) of the compressor (50), and before the drive shaft (80) and the first to third bearings (79, 69, 93) are significantly damaged.

In Embodiment 1, the compressor (50) is configured such that, when the amount of the lubricating oil in the oil reservoir (95) decreases, poor sealing due to a decrease in the amount of the lubricating oil for sealing the compression chamber (61) occurs before poor lubrication occurs on the sliding portions of the drive shaft (80) and the first to third bearings (79, 69, 93). Specifically, the oil supply passage (87) is configured to distribute and supply the lubricating oil in the oil reservoir (95) to the sliding portions of the drive shaft (80) and the first to third bearings (79, 69, 93) earlier than to the compression section (60), and to supply the remaining lubricating oil accumulated in the crank chamber (67) to the compression section (60). Thus, before poor lubrication occurs on the sliding portions of the drive shaft (80) and the first to third bearings (79, 69, 93), poor sealing occurs due to a decrease in the amount of the lubricating oil for sealing the compression chamber (61), and the discharge gas temperature Tdp increases. With such a configuration, the failure prediction unit (23) can detect a sign of failure of the drive shaft (80) and the first to third bearings (79, 69, 93) before poor lubrication occurs on the sliding portions of the drive shaft (80) and the first to third bearings (79, 69, 93), and thus can reliably predict a failure at an early stage.

In Embodiment 1, the oil supply passage (87) serves as an actualizing portion that changes the state of a non-target portion (reduces the amount of the lubricating oil for sealing the compression chamber (61)) different from target portions for the prediction of failure before a change in state of the target portions (poor lubrication on the sliding portions of the drive shaft (80) and the first to third bearings (79, 69, 93)) in conjunction with a change in state in the compressor (50) (a decrease in the amount of the lubricating oil in the oil reservoir (95)), which causes a failure of the drive shaft (80) and the first to third bearings (79, 69, 93) that are the target portions for the prediction of failure.

<Avoidance Operation>

When the predictive sign condition is satisfied, the failure prediction unit (23) performs an avoidance operation of avoiding a failure of the drive shaft (80) and the first to third bearings (79, 69, 93). The avoidance operation is an operation that needs to be performed when there is a predictive sign of failure (there is a possibility of failure) of the drive shaft (80) and the first to third bearings (79, 69, 93).

The failure prediction unit (23) performs an operation of changing the operating state of the compressor (50) from a normal state to a lightly loaded state as the avoidance operation. The failure prediction unit (23) performs this operation every time the predictive sign condition is satisfied.

The normal state is an operating state of the compressor (50) while the predictive sign condition is not satisfied. In the normal state, the rotational speed of the compressor (50) is a value set by the capacity control unit (22). On the other hand, the lightly loaded state is an operating state of the compressor (50) in which the load acting on the drive shaft (80) and the first to third bearings (79, 69, 93) is lighter than the load at the time of determination regarding whether the predictive sign condition is satisfied. The lightly loaded state according to this embodiment is an operating state in which the rotational speed of the compressor (50) is lower than the rotational speed of the compressor (50) at the time of determination regarding whether the predictive sign condition is satisfied.

Thus, the failure prediction unit (23) performs an operation of lowering the rotational speed of the compressor (50) below the rotational speed at the time of determination operation (specifically, an operation of lowering the output frequency of the motor drive device (45) below the value set by the capacity control unit (22) at the time of determination operation) as the avoidance operation.

After the operating state of the compressor (50) is changed from the normal state to the lightly loaded state, the failure prediction unit (23) measures the duration of the lightly loaded state. While the lightly loaded state continues, the lubricating oil remaining in the heat exchangers (33, 36) and other components of the refrigerant circuit (30) may return to the compressor (50) together with the refrigerant. This may allow sufficient oil to be supplied to the drive shaft (80) and the first to third bearings (79, 69, 93).

When the duration of the lightly loaded state reaches a predetermined reference period, the failure prediction unit (23) restores the operating state of the compressor (50) from the lightly loaded state to the normal state. In this case, the failure prediction unit (23) restores the operating capacity of the compressor (50) (specifically, the output frequency of the motor drive device (45)) to a value immediately before the operating state of the compressor (50) changes to the lightly loaded state.

The failure prediction unit (23) according to this embodiment performs an operation of giving a warning of that there is a predictive sign of failure of the drive shaft (80) and the first to third bearings (79, 69, 93) as the avoidance operation. The failure prediction unit (23) performs this operation when the predictive sign condition is satisfied.

Specifically, the failure prediction unit (23) displays, on the display (16) of the remote control unit (15), an indication that there is a predictive sign of failure of the drive shaft (80) and the first to third bearings (79, 69, 93). This indication may be, for example, character information such as “Compressor possibly in abnormal state” or an error code indicating that there is a predictive sign of failure on the drive shaft (80) and the first to third bearings (79, 69, 93). For example, the indication may be a notification for prompting a response such as repair or replacement of a component. For example, the failure prediction unit (23) may notify the outside (an administrator who makes a response such as repair or replacement of a component, a management server, or the like) that there is a predictive sign of failure of the drive shaft (80) and the first to third bearings (79, 69, 93). The notification may be provided together with the indication on the display (16) of the remote control unit (15), or may be performed instead of the indication on the display (16) of the remote control unit (15).

Advantageous Effects of Embodiment 1

The compressor system (40) according to this embodiment includes the compressor (50), and the main controller (21) (prediction device) that predicts a failure by detecting a sign of failure of the drive shaft (80) and the first to third bearings (79, 69, 93) (target portions) of the compressor (50). The compressor (50) includes the motor (55), the compressor mechanism section (100), and the oil supply passage (87) (actualizing portion) provided in the compressor mechanism section (100) and configured to change the discharge gas temperature Tdp (predetermined index) in conjunction with a change in state in the compressor (50) (a decrease in the amount of the lubricating oil in the oil reservoir (95)), which causes a failure of the drive shaft (80) and the first to third bearings (79, 69, 93) (target portions). The prediction device (21) includes the failure prediction unit (23) that predicts a failure by detecting a sign of failure of the drive shaft (80) and the first to third bearings (79, 69, 93) (target portions) based on a change in the discharge gas temperature Tdp (predetermined index).

The failure of the drive shaft (80) and the first to third bearings (79, 69, 93) of the compressor (50) refers to a state in which the drive shaft (80) and the first to third bearings (79, 69, 93) of the compressor (50) are inoperable due to seizure or the like.

In the compressor system (40) according to this embodiment, the oil supply passage (87) is configured such that the discharge gas temperature Tdp changes in conjunction with a decrease in the amount of the lubricating oil in the oil reservoir (95), which causes a failure of the drive shaft (80) and the first to third bearings (79, 69, 93). A failure is predicted by detecting a sign of failure of the drive shaft (80) and the first to third bearings (79, 69, 93) based on a change in the discharge gas temperature Tdp. Thus, with the compressor system (40), it is possible to predict a failure by detecting a sign of failure of the drive shaft (80) and the first to third bearings (79, 69, 93) at an early stage after the amount of the lubricating oil in the oil reservoir (95) decreases.

In the compressor system (40) according to this embodiment, as described above, the oil supply passage (87) is configured to distribute and supply the lubricating oil in the oil reservoir (95) to the sliding portions of the drive shaft (80) and the first to third bearings (79, 69, 93) earlier than to the compression section (60), and to supply the remaining lubricating oil accumulated in the crank chamber (67) to the compression section (60). In the compressor (50), when the amount of the lubricating oil in the oil reservoir (95) decreases (a change in state in the compressor (50), which causes a failure of the target portion, occurs), the amount of the lubricating oil for sealing the compression chamber (61) (the state of the non-target portion different from the target portions) decreases before the drive shaft (80) and the first to third bearings (79, 69, 93) deteriorate due to a shortage of the lubricating oil (the state of the target portions changes). As a result, various indices (e.g., discharge gas temperature Tdp) indicating the operating state of the compression section (60) change.

In the compressor system (40) according to this embodiment, attention is paid to the fact that, when the amount of the lubricating oil in the oil reservoir (95) decreases, the amount of the lubricating oil for sealing the compression chamber (61) (the amount of sealing oil) decreases and various indices indicating the operating state of the compression section (60) change. The various indices indicating the operating state of the compression section (60) are used for predicting a failure of the drive shaft (80) and the first to third bearings (79, 69, 93). Thus, with the compressor system (40) according to this embodiment, it is possible to predict a failure by detecting a sign of failure of the drive shaft (80) and the first to third bearings (79, 69, 93) after the amount of the lubricating oil in the oil reservoir (95) decreases and before the drive shaft (80) and the first to third bearings (79, 69, 93) are significantly damaged.

In the compressor system (40) according to this embodiment, the temperature of the discharge gas discharged from the compression section (60) (discharge gas temperature Tdp) is used as an index indicating the operating state of the compression section (60), which changes in conjunction with the amount of the lubricating oil for sealing the compression chamber (61), to predict a failure of the drive shaft (80) and the first to third bearings (79, 69, 93).

When the amount of the lubricating oil for sealing the compression chamber (61) decreases, the amount of heat transferred from the refrigerant (fluid) to the lubricating oil decreases, and the leaked refrigerant is re-compressed, which increases the temperature of the discharge refrigerant and the discharge gas temperature Tdp. Thus, with the compressor system (40), by using the discharge gas temperature Tdp for predicting a failure of the drive shaft (80) and the first to third bearings (79, 69, 93), it is possible to predict a failure by detecting a sign of failure of the drive shaft (80) and the first to third bearings (79, 69, 93) before the drive shaft (80) and the first to third bearings (79, 69, 93) of the compressor (50) are significantly damaged. With the compressor system, a sign of failure of the drive shaft (80) and the first to third bearings (79, 69, 93) of the compressor (50) is detected not by detecting a decrease in the amount of sealing oil, which is difficult to be detected, but by detecting the temperature of the discharge gas, which changes in conjunction with a change in the amount of sealing oil. Thus, a failure can be easily predicted.

The discharge gas temperature Tdp changes in conjunction with a change in the amount of sealing oil for the compression chamber (61), but is not affected by friction between the drive shaft (80) and the first to third bearings (79, 69, 93). Thus, with the discharge gas temperature Tdp, it is easy to grasp the deterioration of the sealability of the compression chamber (61), and the accuracy of prediction is improved by the discharge gas temperature Tdp being detected as an index indicating the deterioration of the sealability of the compression chamber (61).

In the compressor system (40) according to this embodiment, the oil supply passage (87) is configured to distribute and supply the lubricating oil in the oil reservoir (95) to the sliding portions of the drive shaft (80) and the first to third bearings (79, 69, 93) earlier than to the compression section (60), and to supply the remaining lubricating oil accumulated in the crank chamber (67) to the compression section (60). Thus, in the compressor system (40), although the lubricating oil is supplied from the oil reservoir (95) of the compressor (50) to the compression section (60) and the sliding portions of the drive shaft (80) and the first to third bearings (79, 69, 93), when the amount of the lubricating oil in the oil reservoir (95) decreases, poor sealing due to a decrease in the amount of the lubricating oil for sealing the compression chamber (61) occurs before poor lubrication occurs on the sliding portions of the drive shaft (80) and the first to third bearings (79, 69, 93), and various indices indicating the operating state of the compression section (60) change.

In the compressor system (40) according to this embodiment, the discharge gas temperature Tdp, which increases due to poor sealing caused by a decrease in the amount of the lubricating oil for sealing the compression chamber (61), is used to predict a failure of the drive shaft (80) and the first to third bearings (79, 69, 93). Thus, with the compressor system (40) according to this embodiment, it is possible to predict a failure by detecting a sign of failure of the drive shaft (80) and the first to third bearings (79, 69, 93) after the amount of the oil in the oil reservoir (95) decreases and before the drive shaft (80) and the first to third bearings (79, 69, 93) are significantly damaged due to poor lubrication.

The air conditioner (refrigeration apparatus) (10) according to this embodiment includes the compressor system (40), and the refrigerant circuit (30) to which the compressor (50) of the compressor system (40) is connected and that performs a refrigeration cycle by circulating a refrigerant.

Since the air conditioner (refrigeration apparatus) (10) according to this embodiment includes the compressor system (40), it is possible to predict a failure by detecting a sign of failure of the drive shaft (80) and the first to third bearings (79, 69, 93) of the compressor (50) at an early stage.

Although the discharge gas temperature Tdp is obtained by the temperature sensor (111) embedded in the vicinity of the discharge port (dp) in Embodiment 1, the discharge gas temperature Tdp may be obtained by a temperature sensor provided on an outer surface of the casing (51) of the compressor (50). When the temperature sensor that measures the discharge gas temperature Tdp is away from the discharge port (dp) of the compressor (50), the discharge gas temperature Tdp is likely to be affected by the other components or the lubricating oil. Thus, it is difficult to grasp a change in the discharge gas temperature Tdp due to re-compression, and the accuracy of prediction is lowered. Thus, as in Embodiment 1, the temperature sensor (111) embedded in the vicinity of the discharge port (dp) can sensitively grasp a change in the discharge gas temperature Tdp due to re-compression, which is most preferable for improving the accuracy of prediction. Even when the temperature sensor is provided on the outer surface of the casing (51) of the compressor (50), the accuracy of prediction can be improved as long as the temperature sensor is provided at a position close to the discharge port (dp), as in Embodiment 1.

Embodiment 2

An air conditioner (10) according to Embodiment 2 is different from the air conditioner (10) according to Embodiment 1 in that a pressure sensor (112) that detects the internal pressure of the compression chamber (61) is provided instead of the temperature sensor (111) that detects the temperature of the discharge gas, and the determination operation performed by the failure prediction unit (23) is changed. The other configurations and operations are similar to those of Embodiment 1. Here, differences from Embodiment 1 will be described.

<Pressure Sensor>

As illustrated in FIG. 4, the pressure sensor (112) is embedded in the compression section (60) so as to be able to detect the internal pressure of the compression chamber (61) of the compressor (50). A plurality of pressure sensors (112) are provided so as to be able to detect the internal pressure of the compression chamber (61) from the start of suction to the end of discharge. The pressure sensor (112) detects the internal pressure of the compression chamber (61), converts the detected internal pressure into an electric signal, and outputs the electric signal to the main controller (21).

<Determination Operation>

A determination operation of the failure prediction unit (23) will be described below. Also in this embodiment, the failure prediction unit (23) repeatedly performs a determination operation of determining whether a predictive sign condition is satisfied every predetermined period (e.g., every 30 seconds). In this embodiment, the predictive sign condition is a condition that an increase amount ΔW (W−Wn) of a compression-chamber workload W of the compressor (50) with respect to a predetermined normal value Wn is greater than or equal to a determination reference value Wb (ΔW≥Wb).

First, the failure prediction unit (23) calculates the workload of the compression chamber (compression-chamber workload W) while each of the suction, compression, and discharge processes of the compressor (50) is performed. As presented in FIG. 5, the failure prediction unit (23) calculates the compression-chamber workload W of the compressor (50) by integrating the volume V of the compression chamber (61) with the internal pressure P (the detection value of the pressure sensor (112)) of the compression chamber (61).

Next, the failure prediction unit (23) calculates the increase amount ΔW of the compression-chamber workload W of the compressor (50) with respect to the predetermined normal value Wn. The normal value Wn is a compression-chamber workload of the compressor (50) in a normal state in which poor lubrication does not occur on each sliding portion of the compressor (50), and the failure prediction unit (23) stores a reference value as the normal value Wn. The failure prediction unit (23) calculates the increase amount ΔW by subtracting the normal value Wn from the compression-chamber workload W of the compressor (50). For example, the normal value Wn may be a value determined in advance for each type of the compressor (50). For example, a test operation may be performed after installation of the compressor system (40), the compression-chamber workload of the compressor (50) in the normal state in which poor lubrication does not occur on each sliding portion of the compressor (50) may be calculated, and the calculated value may be used as the normal value Wn. The normal value Wn is determined for each of operation conditions of the compressor (50) composed of the number of revolutions, the high pressure, and the low pressure.

Next, the failure prediction unit (23) compares the calculated increase amount ΔW with the determination reference value Wb. The failure prediction unit (23) stores a reference value as the determination reference value Wb. When the increase amount ΔW is greater than or equal to the determination reference value Wb (ΔW≥Wb), the failure prediction unit (23) determines that the predictive sign condition is satisfied. That is, the failure prediction unit (23) according to this embodiment determines that the predictive sign condition is satisfied when the increase amount ΔW becomes greater than or equal to the determination reference value Wb for the first time.

As described above, in Embodiment 2, the failure prediction unit (23) calculates the compression-chamber workload W of the compressor (50), and determines whether the predictive sign condition is satisfied (the presence of a predictive sign of failure of the drive shaft (80) and the first to third bearings (79, 69, 93)) based on the compression-chamber workload W of the compressor (50). In Embodiment 2, the compression-chamber workload W of the compressor (50) (an index indicating the operating state of the compression section (60)), which changes in conjunction with the amount of the lubricating oil for sealing the compression chamber (61), is used for the predictive sign condition for the following reason.

In the compressor (50), when the amount of oil or the concentration of the lubricating oil in the oil reservoir (95) decreases, the lubricating state in each sliding portion of the compressor (50) to which the lubricating oil in the oil reservoir (95) is supplied via the oil supply passage (87) shifts from fluid lubrication to mixed lubrication or boundary lubrication. As a result, the drive shaft (80) and the first to third bearings (79, 69, 93) are brought into contact with each other and worn, which leads to seizure or the like, and then a failure may occur on the drive shaft (80) and the first to third bearings (79, 69, 93) (brought into an inoperable state). On the other hand, in the compression section (60), before the lubricating state in each sliding portion shifts from the fluid lubrication to the mixed lubrication or the boundary lubrication, the amount of the lubricating oil for sealing the compression chamber (61) decreases. When the amount of the lubricating oil for sealing the compression chamber (61) decreases, the sealability of the compression chamber (61) deteriorates, and refrigerant leakage occurs in which the refrigerant leaks from the compression chamber (61) with a high internal pressure to the compression chamber (61) with a low internal pressure. When the refrigerant leaks, as presented in FIG. 5, the workload increases in the compression chamber (61) to which the refrigerant has leaked, and the workload decreases in the compression chamber (61) from which the refrigerant has leaked. However, the compression-chamber workload W for one cycle increases as compared to the normal state (the normal state in which poor lubrication does not occur on each sliding portion of the compressor (50)). In Embodiment 2, attention is paid to the compression-chamber workload W of the compressor (50), which increases in conjunction with poor sealing due to a decrease in the amount of the lubricating oil for sealing the compression chamber (61), and the compression-chamber workload W of the compressor (50) is used to determine the presence of a predictive sign of failure of the drive shaft (80) and the first to third bearings (79, 69, 93). Thus, it is possible to predict a failure by detecting a sign of failure of the drive shaft (80) and the first to third bearings (79, 69, 93) after the amount of the oil in the oil reservoir (95) decreases, which causes a failure of the drive shaft (80) and the first to third bearings (79, 69, 93) of the compressor (50), and before the drive shaft (80) and the first to third bearings (79, 69, 93) are significantly damaged.

As described above, the compressor system (40) and the air conditioner (refrigeration apparatus) (10) according to Embodiment 2 also attain effects similar to those of the compressor system (40) and the air conditioner (refrigeration apparatus) (10) according to Embodiment 1.

Modification 1 of Embodiment 2

Modification 1 is obtained by changing the predictive sign condition in Embodiment 2. In Modification 1, the predictive sign condition is a condition that an increase rate Wr ((W−Wn)/Wn) of the compression-chamber workload W of the compressor (50) with respect to a predetermined normal value Wn is greater than or equal to a determination reference value Wb (e.g., 0.1 (10%)) (Wr≥Wb).

The failure prediction unit (23) obtains the compression-chamber workload W of the compressor (50) as in Embodiment 2, and then calculates the increase rate Wr of the compression-chamber workload W of the compressor (50) with respect to the predetermined normal value Wn. The failure prediction unit (23) calculates the increase rate Wr by subtracting the normal value Wn from the compression-chamber workload W of the compressor (50) and dividing the resultant value by the normal value Wn. Then, the failure prediction unit (23) compares the calculated increase rate Wr with the determination reference value Wb, and determines that the predictive sign condition is satisfied when the increase rate Wr is greater than or equal to the determination reference value Wb (Wr≥Wb).

As described above, in the determination operation, even when the target to be compared to the determination reference value Wb is the increase rate Wr ((W−Wn)/Wn) of the compression-chamber workload W of the compressor (50) with respect to the predetermined normal value Wn, effects similar to those of Embodiment 2 can be attained.

Embodiment 3

An air conditioner (10) according to Embodiment 3 is different from the air conditioner (10) according to Embodiment 1 in that a pressure sensor (112) that detects the internal pressure of the compression chamber (61) is provided instead of the temperature sensor (111) that detects the temperature of the discharge gas, and the determination operation performed by the failure prediction unit (23) is changed. The other configurations and operations are similar to those of Embodiment 1. Here, differences from Embodiment 1 will be described.

<Pressure Sensor>

As illustrated in FIG. 4, the pressure sensor (112) is embedded in the compression section (60) so as to be able to detect the internal pressure of the compression chamber (61) of the compressor (50). A plurality of pressure sensors (112) are provided so as to be able to detect the internal pressure of the compression chamber (61) from the start of suction to the end of discharge. The pressure sensor (112) detects the internal pressure of the compression chamber (61), converts the detected internal pressure into an electric signal, and outputs the electric signal to the main controller (21).

<Determination Operation>

A determination operation of the failure prediction unit (23) will be described below. Also in this embodiment, the failure prediction unit (23) repeatedly performs a determination operation of determining whether a predictive sign condition is satisfied every predetermined period (e.g., every 30 seconds). In this embodiment, the predictive sign condition is a condition that an increase amount ΔP (P−Pn) of the internal pressure P of the compressor (50) with respect to a predetermined normal value Pn is greater than or equal to a determination reference value Pb (ΔP≥Pb).

First, the failure prediction unit (23) calculates the increase amount ΔP of the internal pressure P of the compressor (50) with respect to the predetermined normal value Pn. The normal value Pn is an internal pressure of the compressor (50) in a normal state in which poor lubrication does not occur on each sliding portion of the compressor (50), and the failure prediction unit (23) stores a reference value as the normal value Pn. The failure prediction unit (23) calculates the increase amount ΔP by subtracting the normal value Pn from the internal pressure P of the compressor (50). For example, the normal value Pn may be a value determined in advance for each type of the compressor (50). For example, a test operation may be performed after installation of the compressor system (40), the internal pressure of the compressor (50) in the normal state in which poor lubrication does not occur on each sliding portion of the compressor (50) may be calculated, and the calculated value may be used as the normal value Pn. The normal value Pn is determined for each of operation conditions of the compressor (50) composed of the number of revolutions, the high pressure, and the low pressure.

Next, the failure prediction unit (23) compares the calculated increase amount ΔP with the determination reference value Pb. The failure prediction unit (23) stores a reference value as the determination reference value Pb. When the increase amount ΔP is greater than or equal to the determination reference value Pb (ΔP≥Pb), the failure prediction unit (23) determines that the predictive sign condition is satisfied. That is, the failure prediction unit (23) according to this embodiment determines that the predictive sign condition is satisfied when the increase amount ΔP becomes greater than or equal to the determination reference value Pb for the first time.

As described above, in Embodiment 3, the failure prediction unit (23) calculates the internal pressure P of the compressor (50), and determines whether the predictive sign condition is satisfied (the presence of a predictive sign of failure of the drive shaft (80) and the first to third bearings (79, 69, 93)) based on the internal pressure P of the compressor (50). In Embodiment 3, the internal pressure P of the compressor (50) (an index indicating the operating state of the compression section (60)), which changes in conjunction with the amount of the lubricating oil for sealing the compression chamber (61), is used for the predictive sign condition for the following reason.

In the compressor (50), when the amount of oil or the concentration of the lubricating oil in the oil reservoir (95) decreases, the lubricating state in each sliding portion of the compressor (50) to which the lubricating oil in the oil reservoir (95) is supplied via the oil supply passage (87) shifts from fluid lubrication to mixed lubrication or boundary lubrication. As a result, the drive shaft (80) and the first to third bearings (79, 69, 93) are brought into contact with each other and worn, which leads to seizure or the like, and then a failure may occur on the drive shaft (80) and the first to third bearings (79, 69, 93) (brought into an inoperable state). On the other hand, in the compression section (60), before the lubricating state in each sliding portion shifts from the fluid lubrication to the mixed lubrication or the boundary lubrication, the amount of the lubricating oil for sealing the compression chamber (61) decreases. When the amount of the lubricating oil for sealing the compression chamber (61) decreases, the sealability of the compression chamber (61) deteriorates, and refrigerant leakage occurs in which the refrigerant leaks from the compression chamber (61) with a high internal pressure to the compression chamber (61) with a low internal pressure. When the refrigerant leaks, as presented in FIG. 5, the internal pressure P in the compression chamber (61) to which the refrigerant has leaked increases as compared to the normal state (the normal state in which poor lubrication does not occur on each sliding portion of the compressor (50)), and the internal pressure P in the compression chamber (61) from which the refrigerant has leaked decreases as compared to the normal state. In Embodiment 3, attention is paid to the internal pressure P of the compressor (50), which increases or decreases in conjunction with poor sealing due to a decrease in the amount of the lubricating oil for sealing the compression chamber (61), and the internal pressure P of the compressor (50) is used to determine the presence of a predictive sign of failure of the drive shaft (80) and the first to third bearings (79, 69, 93). Thus, it is possible to predict a failure by detecting a sign of failure of the drive shaft (80) and the first to third bearings (79, 69, 93) after the amount of the oil in the oil reservoir (95) decreases, which causes a failure of the drive shaft (80) and the first to third bearings (79, 69, 93) of the compressor (50), and before the drive shaft (80) and the first to third bearings (79, 69, 93) are significantly damaged.

In Embodiment 3, when the refrigerant leaks, the internal pressure P detected by the pressure sensor (112) at the timing (rotational angle) at which the internal pressure P having been increased as compared to the normal state is detected is used for the determination operation. In the determination operation, the predictive sign condition is the condition that the increase amount ΔP (P−Pn) of the internal pressure P of the compressor (50) with respect to the predetermined normal value Pn is greater than or equal to the determination reference value Pb (ΔP≥Pb). Alternatively, the internal pressure P detected by the pressure sensor (112) at the timing (rotational angle) at which the internal pressure P having been lowered as compared to the normal state may be used for the determination operation. In the determination operation, the predictive sign condition may be a condition that a decrease amount ΔP (Pn−P) of the internal pressure P of the compressor (50) with respect to a predetermined normal value Pn is greater than or equal to a determination reference value Pb (ΔP≥Pb).

As described above, the compressor system (40) and the air conditioner (refrigeration apparatus) (10) according to Embodiment 3 also attain effects similar to those of the compressor system (40) and the air conditioner (refrigeration apparatus) (10) according to Embodiment 1. The internal pressure P of the compression chamber (61) changes in conjunction with a change in the amount of sealing oil for the compression chamber (61), but is not affected by friction between the drive shaft (80) and the first to third bearings (79, 69, 93). Thus, with the internal pressure P of the compression chamber (61), it is easy to grasp the deterioration of the sealability of the compression chamber (61), and the accuracy of prediction is improved by the internal pressure P of the compression chamber (61) being detected as an index indicating the deterioration of the sealability of the compression chamber (61).

Modification 1 of Embodiment 3

Modification 1 is obtained by changing the predictive sign condition in Embodiment 3. In Modification 1, the predictive sign condition is a condition that an increase rate Pr ((P−Pn)/Pn) of the internal pressure P of the compressor (50) with respect to a predetermined normal value Pn is greater than or equal to a determination reference value Pb (e.g., 0.1 (10%)) (Pr≥Pb).

The failure prediction unit (23) calculates the increase rate Pr of the internal pressure P of the compressor (50) with respect to the predetermined normal value Pn as in Embodiment 3. The failure prediction unit (23) calculates the increase rate Pr by subtracting the normal value Pn from the internal pressure P of the compressor (50) and dividing the resultant value by the normal value Pn. Then, the failure prediction unit (23) compares the calculated increase rate Pr with the determination reference value Pb, and determines that the predictive sign condition is satisfied when the increase rate Pr is greater than or equal to the determination reference value Pb (Pr≥Pb).

As described above, in the determination operation, even when the target to be compared to the determination reference value Pb is the increase rate Pr ((P−Pn)/Pn) of the internal pressure P of the compressor (50) with respect to the predetermined normal value Pn, effects similar to those of Embodiment 3 can be attained.

Embodiment 4

An air conditioner (10) according to Embodiment 4 is different from the air conditioner (10) according to Embodiment 1 in that a pressure sensor (112) that detects the internal pressure of the compression chamber (61) is provided instead of the temperature sensor (111) that detects the temperature of the discharge gas, and the determination operation performed by the failure prediction unit (23) is changed. The other configurations and operations are similar to those of Embodiment 1. Here, differences from Embodiment 1 will be described.

<Pressure Sensor>

As illustrated in FIG. 4, the pressure sensor (112) is embedded in the compression section (60) so as to be able to detect the internal pressure of the compression chamber (61) of the compressor (50). A plurality of pressure sensors (112) are provided so as to be able to detect the internal pressure of the compression chamber (61) from the start of suction to the end of discharge. The pressure sensor (112) detects the internal pressure of the compression chamber (61), converts the detected internal pressure into an electric signal, and outputs the electric signal to the main controller (21).

<Determination Operation>

A determination operation of the failure prediction unit (23) will be described below. Also in this embodiment, the failure prediction unit (23) repeatedly performs a determination operation of determining whether a predictive sign condition is satisfied every predetermined period (e.g., every 30 seconds). In this embodiment, the predictive sign condition is a condition that an increase amount Δκ (κ−Kn) of a polytropic index κ in the compression process of the compressor (50) with respect to a predetermined normal value Kn is greater than or equal to a determination reference value κb (ΔK≥κb). The polytropic index κ is an index indicated in the relational expression PV^κ=const. between the internal pressure P and the volume V of the compression chamber (61) in the compression process, and indicates the state of a change in internal pressure with respect to a change in volume.

First, the failure prediction unit (23) calculates the polytropic index κ in the compression process of the compressor (50). The failure prediction unit (23) calculates the polytropic index κ from the internal pressure P (the detection value of the pressure sensor (112)) in the compression process of the compression chamber (61) and the volume V of the compression chamber (61) at that time.

Next, the failure prediction unit (23) calculates the increase amount OK of the polytropic index κ in the compression process of the compressor (50) with respect to the predetermined normal value Kn. The normal value Kn is a polytropic index in the compression process of the compressor (50) in a normal state in which poor lubrication does not occur on each sliding portion of the compressor (50), and the failure prediction unit (23) stores a reference value as the normal value κn. The failure prediction unit (23) calculates the increase amount Δκ by subtracting the normal value κn from the polytropic index in the compression process of the compressor (50). For example, the normal value κn may be a value determined in advance for each type of the compressor (50). For example, a test operation may be performed after installation of the compressor system (40), the polytropic index in the compression process of the compressor (50) in the normal state in which poor lubrication does not occur on each sliding portion of the compressor (50) may be calculated, and the calculated value may be used as the normal value κn. The normal value kn is determined for each of operation conditions of the compressor (50) composed of the number of revolutions, the high pressure, and the low pressure.

Next, the failure prediction unit (23) compares the calculated increase amount Δκ with the determination reference value κb. The failure prediction unit (23) stores a reference value as the determination reference value κb. When the increase amount OK is greater than or equal to the determination reference value κb (ΔK≥κb), the failure prediction unit (23) determines that the predictive sign condition is satisfied. That is, the failure prediction unit (23) according to this embodiment determines that the predictive sign condition is satisfied when the increase amount Δκ becomes greater than or equal to the determination reference value κb for the first time.

As described above, in Embodiment 4, the failure prediction unit (23) calculates the polytropic index κ in the compression process of the compressor (50), and determines whether the predictive sign condition is satisfied (the presence of a predictive sign of failure of the drive shaft (80) and the first to third bearings (79, 69, 93)) based on the polytropic index κ in the compression process of the compressor (50). In Embodiment 4, the polytropic index κ in the compression process of the compressor (50) (an index indicating the operating state of the compression section (60)), which changes in conjunction with the amount of the lubricating oil for sealing the compression chamber (61), is used for the predictive sign condition for the following reason.

In the compressor (50), when the amount of oil or the concentration of the lubricating oil in the oil reservoir (95) decreases, the lubricating state in each sliding portion of the compressor (50) to which the lubricating oil in the oil reservoir (95) is supplied via the oil supply passage (87) shifts from fluid lubrication to mixed lubrication or boundary lubrication. As a result, the drive shaft (80) and the first to third bearings (79, 69, 93) are brought into contact with each other and worn, which leads to seizure or the like, and then a failure may occur on the drive shaft (80) and the first to third bearings (79, 69, 93) (brought into an inoperable state). On the other hand, in the compression section (60), before the lubricating state in each sliding portion shifts from the fluid lubrication to the mixed lubrication or the boundary lubrication, the amount of the lubricating oil for sealing the compression chamber (61) decreases. When the amount of the lubricating oil for sealing the compression chamber (61) decreases, the sealability of the compression chamber (61) deteriorates, and refrigerant leakage occurs in which the refrigerant leaks from the compression chamber (61) with a high internal pressure to the compression chamber (61) with a low internal pressure. When the refrigerant leaks, as presented in FIG. 5, the internal pressure P in the compression chamber (61) to which the refrigerant has leaked increases as compared to the normal state (the normal state in which poor lubrication does not occur on each sliding portion of the compressor (50)), and the polytropic index κ in the compression process of the compressor (50) also increases as compared to the normal state. The internal pressure P in the compression chamber (61) from which the refrigerant has leaked decreases as compared to the normal state, and the polytropic index κ in the compression process of the compressor (50) also decreases as compared to the normal state. In Embodiment 4, attention is paid to the polytropic index κ in the compression process of the compressor (50), which increases or decreases in conjunction with poor sealing due to a decrease in the amount of the lubricating oil for sealing the compression chamber (61), and the polytropic index κ in the compression process of the compressor (50) is used to determine the presence of a predictive sign of failure of the drive shaft (80) and the first to third bearings (79, 69, 93). Thus, it is possible to predict a failure by detecting a sign of failure of the drive shaft (80) and the first to third bearings (79, 69, 93) after the amount of the oil in the oil reservoir (95) decreases, which causes a failure of the drive shaft (80) and the first to third bearings (79, 69, 93) of the compressor (50), and before the drive shaft (80) and the first to third bearings (79, 69, 93) are significantly damaged.

In Embodiment 4, when the refrigerant leaks, the internal pressure P detected by the pressure sensor (112) at the timing (rotational angle) at which the internal pressure P having been increased as compared to the normal state is detected is used for the determination operation. In the determination operation, the predictive sign condition is the condition that the increase amount Δκ (κ−κn) of the polytropic index κ in the compression process of the compressor (50) with respect to the predetermined normal value κn is greater than or equal to the determination reference value κb (ΔK≥κb). Alternatively, the internal pressure P detected by the pressure sensor (112) at the timing (rotational angle) at which the internal pressure P having been lowered as compared to the normal state may be used for the determination operation. In the determination operation, the predictive sign condition may be a condition that a decrease amount Δκ (κn−κ) of the polytropic index κ in the compression process of the compressor (50) with respect to a predetermined normal value κn is greater than or equal to a determination reference value κb (ΔK≥κb).

As described above, the compressor system (40) and the air conditioner (refrigeration apparatus) (10) according to Embodiment 4 also attain effects similar to those of the compressor system (40) and the air conditioner (refrigeration apparatus) (10) according to Embodiment 1. The polytropic index κ in the compression process of the compression chamber (61) changes in conjunction with a change in the amount of sealing oil for the compression chamber (61), but is not affected by friction between the drive shaft (80) and the first to third bearings (79, 69, 93). Thus, with the polytropic index κ in the compression process of the compression chamber (61), it is easy to grasp the deterioration of the sealability of the compression chamber (61), and the accuracy of prediction is improved by the polytropic index κ in the compression process of the compression chamber (61) being detected as an index indicating the deterioration of the sealability of the compression chamber (61).

Modification 1 of Embodiment 4

Modification 1 is obtained by changing the predictive sign condition in Embodiment 4. In Modification 1, the predictive sign condition is a condition that an increase rate κr ((κ−κn)/κn) of the polytropic index κ in the compression process of the compressor (50) with respect to a predetermined normal value κn is greater than or equal to a determination reference value κb (e.g., 0.1 (10%)) (κr≥κb).

The failure prediction unit (23) calculates the increase rate κr of the polytropic index κ in the compression process of the compressor (50) with respect to the predetermined normal value κn as in Embodiment 4. The failure prediction unit (23) calculates the increase rate κr by subtracting the normal value κn from the polytropic index κ in the compression process of the compressor (50) and dividing the resultant value by the normal value κn. Then, the failure prediction unit (23) compares the calculated increase rate κr with the determination reference value κb, and determines that the predictive sign condition is satisfied when the increase rate κr is greater than or equal to the determination reference value κb (κr≥κb).

As described above, in the determination operation, even when the target to be compared to the determination reference value κb is the increase rate κr ((κ−κn)/κn) of the polytropic index κ in the compression process of the compressor (50) with respect to the predetermined normal value κn, effects similar to those of Embodiment 4 can be attained.

Embodiment 5

An air conditioner (10) according to Embodiment 5 is different from the air conditioner (10) according to Embodiment 1 in that a power detector (113) that detects the input power to the motor (55) (output alternating-current power of the motor drive device (45)) is provided instead of the temperature sensor (111) that detects the temperature of the discharge gas, and the determination operation performed by the failure prediction unit (23) is changed. The other configurations and operations are similar to those of Embodiment 1. Here, differences from Embodiment 1 will be described.

<Power Detector>

As illustrated in FIG. 6, the power detector (113) is provided in an electric wire (three windings (U-phase, V-phase, and W-phase windings) of the motor (55)) connecting the motor drive device (45) and the compressor (50). The power detector (113) detects the output alternating-current power output from the motor drive device (45) to the motor (55) of the compressor (50) (i.e., the input power to the motor (55)). The power detector (113) outputs the detected input power to the main controller (21). The power detector (113) is not necessarily provided, and the power supplied to the motor (55) may be detected in the motor drive device (45) or the main controller (21).

<Determination Operation>

A determination operation of the failure prediction unit (23) will be described below. Also in this embodiment, the failure prediction unit (23) repeatedly performs a determination operation of determining whether a predictive sign condition is satisfied every predetermined period (e.g., every 30 seconds). In this embodiment, the predictive sign condition is a condition that an increase amount ΔJ (J−Jn) of an amount J of power input to the motor (55) with respect to a predetermined normal value Jn is greater than or equal to a determination reference value Jb (ΔJ≥Jb).

First, the failure prediction unit (23) calculates the amount J of power input to the motor (55) while the drive shaft (80) makes one rotation in the compressor (50) and each of the suction, compression, and discharge processes is performed in the compression chamber (61). The failure prediction unit (23) integrates the input power supplied from the motor drive device (45) to the motor (55) of the compressor (50) (the detection value of the power detector 113)) over the period taken for the drive shaft (80) to make one rotation, thereby calculating the amount J of power input to the motor (55).

Next, the failure prediction unit (23) calculates the increase amount ΔJ of the amount J of power input to the motor (55) with respect to the predetermined normal value Jn. The normal value Jn is the amount of power input to the motor (55) in a normal state in which poor lubrication does not occur on each sliding portion of the compressor (50), and the failure prediction unit (23) stores a reference value as the normal value Jn. The failure prediction unit (23) calculates the increase amount ΔJ by subtracting the normal value Jn from the amount J of power input to the motor (55). For example, the normal value Jn may be a value determined in advance for each type of the compressor (50). For example, a test operation may be performed after installation of the compressor system (40), the amount of power input to the motor (55) in the normal state in which poor lubrication does not occur on each sliding portion of the compressor (50) may be calculated, and the calculated value may be used as the normal value Jn. The normal value Jn is determined for each of operation conditions of the compressor (50) composed of the number of revolutions, the high pressure, and the low pressure.

Next, the failure prediction unit (23) compares the calculated increase amount ΔJ with the determination reference value Jb. The failure prediction unit (23) stores a reference value as the determination reference value Jb. When the increase amount ΔJ is greater than or equal to the determination reference value Jb (ΔJ≥Jb), the failure prediction unit (23) determines that the predictive sign condition is satisfied. That is, the failure prediction unit (23) according to this embodiment determines that the predictive sign condition is satisfied when the increase amount ΔJ becomes greater than or equal to the determination reference value Jb for the first time.

As described above, in Embodiment 5, the failure prediction unit (23) calculates the amount J of power input to the motor (55), and determines whether the predictive sign condition is satisfied (the presence of a predictive sign of failure of the drive shaft (80) and the first to third bearings (79, 69, 93)) based on the amount J of power input to the motor (55). In Embodiment 5, the amount J of power input to the motor (55) (an index indicating the operating state of the compression section (60)), which changes in conjunction with the amount of the lubricating oil for sealing the compression chamber (61), is used for the predictive sign condition for the following reason.

In the compressor (50), when the amount of oil or the concentration of the lubricating oil in the oil reservoir (95) decreases, the lubricating state in each sliding portion of the compressor (50) to which the lubricating oil in the oil reservoir (95) is supplied via the oil supply passage (87) shifts from fluid lubrication to mixed lubrication or boundary lubrication. As a result, the drive shaft (80) and the first to third bearings (79, 69, 93) are brought into contact with each other and worn, which leads to seizure or the like, and then a failure may occur on the drive shaft (80) and the first to third bearings (79, 69, 93) (brought into an inoperable state). On the other hand, in the compression section (60), before the lubricating state shifts from the fluid lubrication to the mixed lubrication or the boundary lubrication, the amount of the lubricating oil for sealing the compression chamber (61) decreases. When the amount of the lubricating oil for sealing the compression chamber (61) decreases, the sealability of the compression chamber (61) deteriorates, and refrigerant leakage occurs in which the refrigerant leaks from the compression chamber (61) with a high internal pressure to the compression chamber (61) with a low internal pressure. When the refrigerant leaks, as presented in FIG. 5, the workload increases in the compression chamber (61) to which the refrigerant has leaked, and the workload decreases in the compression chamber (61) from which the refrigerant has leaked. However, the compression-chamber workload W for one cycle increases as compared to the normal state (the normal state in which poor lubrication does not occur on each sliding portion of the compressor (50)). The amount J of power input to the motor (55) is obtained by adding the workload of friction to the compression-chamber workload W. Thus, when the refrigerant leaks, the amount J of power input to the motor (55) also increases as compared to the normal state. In Embodiment 5, attention is paid to the amount J of power input to the motor (55), which increases in conjunction with poor sealing due to a decrease in the amount of the lubricating oil for sealing the compression chamber (61), and the amount J of power input to the motor (55) is used to determine the presence of a predictive sign of failure of the drive shaft (80) and the first to third bearings (79, 69, 93). Thus, it is possible to predict a failure by detecting a sign of failure of the drive shaft (80) and the first to third bearings (79, 69, 93) after the amount of the oil in the oil reservoir (95) decreases, which causes a failure of the drive shaft (80) and the first to third bearings (79, 69, 93) of the compressor (50), and before the drive shaft (80) and the first to third bearings (79, 69, 93) are significantly damaged.

As described above, the compressor system (40) and the air conditioner (refrigeration apparatus) (10) according to Embodiment 5 also attain effects similar to those of the compressor system (40) and the air conditioner (refrigeration apparatus) (10) according to Embodiment 1.

Modification 1 of Embodiment 5

Modification 1 is obtained by changing the predictive sign condition in Embodiment 5. In Modification 1, the predictive sign condition is a condition that an increase rate Jr ((J−Jn)/Jn) of the amount J of power input to the motor (55) with respect to a predetermined normal value Jn is greater than or equal to a determination reference value Jb (e.g., 0.1 (10%)) (Jr≥Jb).

The failure prediction unit (23) obtains the amount J of power input to the motor (55) as in Embodiment 5, and then calculates the increase rate Jr of the amount J of power input to the motor (55) with respect to the predetermined normal value Jn. The failure prediction unit (23) calculates the increase rate Jr by subtracting the normal value Jn from the amount J of power input to the motor (55) and dividing the resultant value by the normal value Jn. Then, the failure prediction unit (23) compares the calculated increase rate Jr with the determination reference value Jb, and determines that the predictive sign condition is satisfied when the increase rate Jr is greater than or equal to the determination reference value Jb (Jr≥Jb).

As described above, in the determination operation, even when the target to be compared to the determination reference value Jb is the increase rate Jr ((J−Jn)/Jn) of the amount J of power input to the motor (55) with respect to the predetermined normal value Jn, effects similar to those of Embodiment 5 can be attained.

Embodiment 6

An air conditioner (10) according to Embodiment 6 is different from the air conditioner (10) according to Embodiment 1 in that a suction temperature sensor (114) and a volumetric flow rate sensor (115) are provided instead of the temperature sensor (111) that detects the temperature of the discharge gas, and the determination operation performed by the failure prediction unit (23) is changed. The other configurations and operations are similar to those of Embodiment 1. Here, differences from Embodiment 1 will be described.

<Sensors>

As illustrated in FIG. 7, the outdoor circuit (31) is provided with the suction temperature sensor (114) and the volumetric flow rate sensor (115). The suction temperature sensor (114) is connected to the pipe connecting the suction pipe (52) of the compressor (50) and the second port (P2) of the four-way switching valve (32), and detects the temperature of the refrigerant to be sucked into the compressor (50). The volumetric flow rate sensor (115) is connected to the pipe connecting the suction pipe (52) of the compressor (50) and the second port (P2) of the four-way switching valve (32), and detects the volumetric flow rate of the refrigerant to be sucked into the compressor (50). The suction temperature sensor (114) and the volumetric flow rate sensor (115) convert the temperature of the refrigerant and the detected volumetric flow rates of the refrigerant into electric signals and output the electric signals to the main controller (21).

<Determination Operation>

A determination operation of the failure prediction unit (23) will be described below. Also in this embodiment, the failure prediction unit (23) repeatedly performs a determination operation of determining whether a predictive sign condition is satisfied every predetermined period (e.g., every 30 seconds). In this embodiment, the predictive sign condition is a condition that a decrease amount ΔQ (Qn−Q) of a refrigerating capacity Q of the air conditioner (10) with respect to a predetermined normal value Qn is greater than or equal to a determination reference value Qb (ΔQ≥Qb).

First, the failure prediction unit (23) calculates the refrigerating capacity Q of the air conditioner (10). Specifically, the failure prediction unit (23) obtains a heat absorption amount difference Δq_L and a refrigerant circulation amount G in the evaporator of the refrigerant circuit (30), and calculates the product (Δq_L×G) of the obtained heat absorption amount difference Δq_L and refrigerant circulation amount G as the refrigerating capacity Q of the air conditioner (10). The failure prediction unit (23) obtains the heat absorption amount difference Δq_L from the pressure (the detection value of the suction pressure sensor (26)) and the temperature (the detection value of the suction temperature sensor (114)) of the refrigerant to be sucked into the compressor (50), and obtains the refrigerant circulation amount G from the volumetric flow rate (the detection value of the volumetric flow rate sensor (115)) and the density of the refrigerant to be sucked into the compressor (50).

Next, the failure prediction unit (23) calculates the decrease amount ΔQ of the refrigerating capacity Q of the air conditioner (10) with respect to the predetermined normal value Qn. The normal value Qn is a refrigerating capacity of the air conditioner (10) in a normal state in which poor lubrication does not occur on each sliding portion of the compressor (50), and the failure prediction unit (23) stores a reference value as the normal value Qn. The failure prediction unit (23) calculates the decrease amount ΔQ by subtracting the refrigerating capacity Q of the air conditioner (10) from the normal value Qn. For example, the normal value Qn may be a value determined in advance for each type of the compressor (50). For example, a test operation may be performed after installation of the compressor system (40), the refrigerating capacity of the air conditioner (10) in the normal state in which poor lubrication does not occur on each sliding portion of the compressor (50) may be calculated, and the calculated value may be used as the normal value Qn. The normal value Qn is determined for each of conditions composed of the number of revolutions and the heat absorption amount difference.

Next, the failure prediction unit (23) compares the calculated decrease amount ΔQ with the determination reference value Qb. The failure prediction unit (23) stores a reference value as the determination reference value Qb. When the decrease amount ΔQ is greater than or equal to the determination reference value Qb (ΔQ≥Qb), the failure prediction unit (23) determines that the predictive sign condition is satisfied. That is, the failure prediction unit (23) according to this embodiment determines that the predictive sign condition is satisfied when the decrease amount ΔQ becomes greater than or equal to the determination reference value Qb for the first time.

As described above, in Embodiment 6, the failure prediction unit (23) calculates the refrigerating capacity Q of the air conditioner (10), and determines whether the predictive sign condition is satisfied (the presence of a predictive sign of failure of the drive shaft (80) and the first to third bearings (79, 69, 93)) based on the refrigerating capacity Q of the air conditioner (10). In Embodiment 6, the refrigerating capacity Q of the air conditioner (10) (an index indicating the operating state of the compression section (60)), which changes in conjunction with the amount of the lubricating oil for sealing the compression chamber (61), is used for the predictive sign condition for the following reason.

In the compressor (50), when the amount of oil or the concentration of the lubricating oil in the oil reservoir (95) decreases, the lubricating state in each sliding portion of the compressor (50) to which the lubricating oil in the oil reservoir (95) is supplied via the oil supply passage (87) shifts from fluid lubrication to mixed lubrication or boundary lubrication. As a result, the drive shaft (80) and the first to third bearings (79, 69, 93) are brought into contact with each other and worn, which leads to seizure or the like, and then a failure may occur on the drive shaft (80) and the first to third bearings (79, 69, 93) (brought into an inoperable state). On the other hand, in the compression section (60), before the lubricating state in each sliding portion shifts from the fluid lubrication to the mixed lubrication or the boundary lubrication, the amount of the lubricating oil for sealing the compression chamber (61) decreases. When the amount of the lubricating oil for sealing the compression chamber (61) decreases, the sealability of the compression chamber (61) deteriorates, and refrigerant leakage occurs in which the refrigerant leaks from the compression chamber (61) with a high internal pressure to the compression chamber (61) with a low internal pressure. When the refrigerant leaks, high-pressure gas (refrigerant) that has leaked out from the high-pressure side flows into the suction side, whereby the refrigerant circulation amount G in the refrigerant circuit (30) decreases as compared to the normal state (the normal state in which poor lubrication does not occur on each sliding portion of the compressor (50)), and the refrigerating capacity Q of the air conditioner (10) also decreases. In Embodiment 6, attention is paid to the refrigerating capacity Q of the air conditioner (10), which decreases in conjunction with poor sealing due to a decrease in the amount of the lubricating oil for sealing the compression chamber (61), and the refrigerating capacity Q of the air conditioner (10) is used to determine the presence of a predictive sign of failure of the drive shaft (80) and the first to third bearings (79, 69, 93). Thus, it is possible to predict a failure by detecting a sign of failure of the drive shaft (80) and the first to third bearings (79, 69, 93) after the amount of the oil in the oil reservoir (95) decreases, which causes a failure of the drive shaft (80) and the first to third bearings (79, 69, 93) of the compressor (50), and before the drive shaft (80) and the first to third bearings (79, 69, 93) are significantly damaged.

As described above, the compressor system (40) and the air conditioner (refrigeration apparatus) (10) according to Embodiment 6 also attain effects similar to those of the compressor system (40) and the air conditioner (refrigeration apparatus) (10) according to Embodiment 1.

Modification 1 of Embodiment 6

Modification 1 is obtained by changing the predictive sign condition in Embodiment 6. In Modification 1, the predictive sign condition is a condition that a decrease rate Qr ((Qn−Q)/Qn) of the refrigerating capacity Q of the air conditioner (10) with respect to a predetermined normal value Qn is greater than or equal to a determination reference value Qb (e.g., 0.1 (10%)) (Qr≥Qb).

The failure prediction unit (23) obtains the refrigerating capacity Q of the air conditioner (10) as in Embodiment 6, and then calculates the decrease rate Qr of the refrigerating capacity Q of the air conditioner (10) with respect to the predetermined normal value Qn. The failure prediction unit (23) calculates the decrease rate Qr by subtracting the refrigerating capacity Q of the air conditioner (10) from the normal value Qn and dividing the resultant value by the normal value Qn. Then, the failure prediction unit (23) compares the calculated decrease rate Qr with the determination reference value Qb, and determines that the predictive sign condition is satisfied when the decrease rate Qr is greater than or equal to the determination reference value Qb (Qr≥Qb).

As described above, in the determination operation, even when the target to be compared to the determination reference value Qb is the decrease rate Qr ((Qn−Q)/Qn) of the refrigerating capacity Q of the air conditioner (10) with respect to the predetermined normal value Qn, effects similar to those of Embodiment 6 can be attained.

Embodiment 7

An air conditioner (10) according to Embodiment 7 is different from the air conditioner (10) according to Embodiment 1 in that a current detector (116) that detects the input current (phase currents of three phases of the motor drive device (45)) for driving the motor (55) and a fundamental frequency detector (117) are provided instead of the temperature sensor (111) that detects the temperature of the discharge gas, and the determination operation performed by the failure prediction unit (23) is changed. The other configurations and operations are similar to those of Embodiment 1. Here, differences from Embodiment 1 will be described.

<Current Detector and Fundamental Frequency Detector>

As illustrated in FIG. 8, the current detector (116) is provided in an electric wire (three windings (U-phase, V-phase, and W-phase windings) of the motor (55)) connecting the motor drive device (45) and the compressor (50), and detects phase currents (U-phase current (iu), V-phase current (iv), and W-phase current (iw)) of three phases. The current detector (116) outputs the detected phase currents of the three phases to the main controller (21). For example, the current detector (116) may detect all of the phase currents (iu, iv, iw) of the three phases or may detect two of the phase currents (iu, iv, iw) of the three phases and derive the remaining one phase current based on the detected currents of the two phases. The current detector (116) is not necessarily provided, and the phase currents (iu, iv, iw) of the three phases may be derived from direct current detected by a shunt resistance (not illustrated) provided in the direct-current unit (not illustrated) of the motor drive device (45) and a switching pattern.

As illustrated in FIG. 8, the fundamental frequency detector (117) is provided in the motor (55) and detects the fundamental frequency (w) of the motor (55). The fundamental frequency (w) of the motor (55) is the frequency of the electrical angle (electrical angle frequency) of the motor (55). The fundamental frequency detector (117) outputs the detected fundamental frequency (ω) of the motor (55) to the main controller (21). The fundamental frequency detector (117) is not necessarily provided, and the fundamental frequency (ω) of the motor (55) may be calculated by another method and estimated in a sensorless manner.

<Determination Operation>

A determination operation of the failure prediction unit (23) will be described below. Also in this embodiment, the failure prediction unit (23) repeatedly performs a determination operation of determining whether a predictive sign condition is satisfied every predetermined period (e.g., every 30 seconds). In this embodiment, the predictive sign condition is a condition that a decrease amount ΔI (In −I) of an index I indicating the waveform of a motor signal correlated with at least one of the voltage, current, and power of the motor (55) with respect to a predetermined normal value In is greater than or equal to a determination reference value Ib (ΔI≥Ib). In Embodiment 7, an example will be described in which a first frequency component I of the motor signal correlated with at least one of the voltage, current, and power of the motor (55) is used as the index I indicating the waveform of the motor signal correlated with at least one of the voltage, current, and power of the motor (55).

First, the failure prediction unit (23) obtains the first frequency component I of the motor signal. The first frequency component I of the motor signal is the rotation frequency of the motor (55) when the motor signal is a direct-current signal, and is a frequency obtained by subtracting or adding the rotation frequency of the motor (55) from or to the fundamental frequency of the motor signal when the motor signal is an alternating-current signal. Details of the first frequency component I of the motor signal will be described later. The rotation frequency of the motor (55) is the frequency of the mechanical angle (mechanical angle frequency) of the motor (55).

Next, the failure prediction unit (23) calculates the decrease amount ΔI of the first frequency component I of the motor signal with respect to the predetermined normal value In. The normal value In is a first frequency component of the motor signal in a normal state in which poor lubrication does not occur on each sliding portion of the compressor (50), and the failure prediction unit (23) stores a reference value as the normal value In. The failure prediction unit (23) calculates the decrease amount ΔI by subtracting the first frequency component I of the motor signal from the normal value In. For example, the normal value In may be a value determined in advance for each type of the compressor (50). For example, a test operation may be performed after installation of the compressor system (40), the first frequency component of the motor signal in the normal state in which poor lubrication does not occur on each sliding portion of the compressor (50) may be obtained, and the obtained value may be used as the normal value In. The normal value In is determined for each of operation conditions of the compressor (50) composed of the number of revolutions, the high pressure, and the low pressure.

Next, the failure prediction unit (23) compares the calculated decrease amount ΔI with the determination reference value Ib. The failure prediction unit (23) stores a reference value as the determination reference value Ib. When the decrease amount ΔI is greater than or equal to the determination reference value Ib (ΔI≥Ib), the failure prediction unit (23) determines that the predictive sign condition is satisfied. That is, the failure prediction unit (23) according to this embodiment determines that the predictive sign condition is satisfied when the decrease amount ΔI becomes greater than or equal to the determination reference value Ib for the first time. For example, when the first frequency component I of the motor signal changes as presented in FIG. 9, the failure prediction unit (23) determines that the predictive sign condition is satisfied at a time t1 of determination at which the decrease amount ΔI of the first frequency component I of the motor signal with respect to the normal value In becomes the determination reference value Ib or later.

As described above, in Embodiment 7, the failure prediction unit (23) obtains the first frequency component I of the motor signal, and determines whether the predictive sign condition is satisfied (the presence of a predictive sign of failure of the drive shaft (80) and the first to third bearings (79, 69, 93)) based on the first frequency component I of the motor signal.

The inventors of the present application have found that the first frequency component I of the motor signal is dominant in the work of the compressor and correlates with the amplitude of the internal pressure (the difference between the minimum pressure and the maximum pressure) during the compression process, and that the amplitude of the internal pressure of the compression chamber (61) during the compression process decreases and the first frequency component I of the motor signal changes when the sealability of the compression chamber (61) deteriorates and the fluid leaks. Thus, in Embodiment 7, the first frequency component I of the motor signal (an index indicating the operating state of the compression section (60)) is used for the predictive sign condition for the following reason.

In the compressor (50), when the amount of oil or the concentration of the lubricating oil in the oil reservoir (95) decreases, the lubricating state in each sliding portion of the compressor (50) to which the lubricating oil in the oil reservoir (95) is supplied via the oil supply passage (87) shifts from fluid lubrication to mixed lubrication or boundary lubrication. As a result, the drive shaft (80) and the first to third bearings (79, 69, 93) are brought into contact with each other and worn, which leads to seizure or the like, and then a failure may occur on the drive shaft (80) and the first to third bearings (79, 69, 93) (brought into an inoperable state). On the other hand, in the compression section (60), before the lubricating state in each sliding portion shifts from the fluid lubrication to the mixed lubrication or the boundary lubrication, the amount of the lubricating oil for sealing the compression chamber (61) decreases. When the amount of the lubricating oil for sealing the compression chamber (61) decreases, the sealability of the compression chamber (61) deteriorates, and refrigerant leakage occurs in which the refrigerant leaks from the compression chamber (61) with a high internal pressure to the compression chamber (61) with a low internal pressure.

When the refrigerant leaks, the waveform of the internal pressure indicating a variation in the internal pressure of the compression chamber (61) changes, and the gas load (the load applied to the orbiting wrap (77) by the pressure of the gas refrigerant) changes. As a result, the waveform of the signal (compression torque signal) indicating the compression torque of the compressor (50), which is represented by the sum total of the products of “the tangential component of the gas load” of each compression chamber (61) and “the distance between the rotation center and the position of the center of gravity of the compression chamber (61)”, changes. The waveform of the compression torque signal and the waveform of the motor output torque signal are in conjunction with each other, and when the refrigerant leaks, a change also appears in the waveform of the motor signal that is in conjunction with the waveform of the motor output torque signal. Specifically, when the refrigerant leaks, the first frequency component I of the motor signal (an example of the index I indicating the waveform of the motor signal) decreases as compared to the normal state (the normal state in which poor lubrication does not occur on each sliding portion of the compressor (50)).

In Embodiment 7, attention is paid to the first frequency component I of the motor signal, which decreases in conjunction with poor sealing due to a decrease in the amount of the lubricating oil for sealing the compression chamber (61), and the first frequency component I of the motor signal is used to determine the presence of a predictive sign of failure of the drive shaft (80) and the first to third bearings (79, 69, 93). Thus, it is possible to predict a failure by detecting a sign of failure of the drive shaft (80) and the first to third bearings (79, 69, 93) after the amount of the oil in the oil reservoir (95) decreases, which causes a failure of the drive shaft (80) and the first to third bearings (79, 69, 93) of the compressor (50), and before the drive shaft (80) and the first to third bearings (79, 69, 93) are significantly damaged.

As described above, the compressor system (40) and the air conditioner (refrigeration apparatus) (10) according to Embodiment 7 also attain effects similar to those of the compressor system (40) and the air conditioner (refrigeration apparatus) (10) according to Embodiment 1. The first frequency component I of the motor signal changes in conjunction with a change in the amount of sealing oil for the compression chamber (61), but is not affected by friction between the drive shaft (80) and the first to third bearings (79, 69, 93). Thus, with the first frequency component I of the motor signal, it is easy to grasp the deterioration of the sealability of the compression chamber (61), and the accuracy of prediction is improved by the first frequency component I of the motor signal being detected as an index indicating the deterioration of the sealability of the compression chamber (61).

<First Frequency Component of Motor Signal>

Next, a specific example of the first frequency component I of the motor signal will be described. The motor signal is a signal correlated with at least one of the voltage, current, and power of the motor (55), and the frequency of the first frequency component I varies depending on whether the motor signal is a direct-current signal or an alternating-current signal. When the motor signal is a direct-current signal, the frequency of the first frequency component I is the rotation frequency (fm) of the motor (55). When the motor signal is an alternating-current signal, the frequency of the first frequency component I is a frequency (f0−fm) obtained by subtracting the rotation frequency (fm) of the motor (55) from the fundamental frequency (f0) of the motor signal, or a frequency (f0+fm) obtained by adding the rotation frequency (fm) of the motor (55) to the fundamental frequency (f0) of the motor signal.

[Specific Examples of Case Where Motor Signal Is Direct-Current Signal]

Examples of the case where the motor signal is a direct-current signal include “a signal correlated with phase currents (iu, iv, iw) of the motor (55)”, “a signal correlated with phase voltages (Vu, Vv, Vw) of the motor (55)”, and “a signal correlated with power of the motor (55)”.

Other examples in which the motor signal is a direct-current signal include “currents (iγ, iδ) obtained by coordinate-transforming the phase currents (iu, iv, iw) of the motor (55) with a phase (ωi·t) of the phase currents (iu, iv, iw) of the motor (55)”, “voltages (Vγ, Vδ) obtained by coordinate-transforming the phase voltages (Vu, Vv, Vw) of the motor (55) with a phase (ωv·t) of the phase voltages (Vu, Vv, Vw) of the motor (55)”, “currents (iζ, iη) obtained by coordinate-transforming the phase currents (iu, iv, iw) of the motor (55) with the phase (ωv·t) of the phase voltages (Vu, Vv, Vw) of the motor (55)”, and “voltages (Vζ, Vη) obtained by coordinate-transforming the phase voltages (Vu, Vv, Vw) of the motor (55) with the phase (ωi·t) of the phase currents (iu, iv, iw) of the motor (55)”.

Other examples in which the motor signal is a direct-current signal include “dq-axis magnetic fluxes (λd, λq) obtained by coordinate transformation in accordance with an armature flux linkage caused by a permanent magnet” and “a magnitude λ0 of an armature flux linkage vector obtained by combining the armature flux linkage of the permanent magnet and an armature reaction”.

In the following description, “the phase currents (iu, iv, iw) of the motor (55)” refer to the phase currents (iu, iv, iw) of the motor (55) detected by the current detector (116). “The phase voltages (Vu, Vv, Vw) of the motor (55)” are the phase voltages (Vu, Vv, Vw) of the motor (55) indicated by the voltage instruction values used inside the main controller (21), or the phase voltages (Vu, Vv, Vw) of the motor (55) detected by a voltage detector (not illustrated) provided in the motor drive device (45). “The fundamental frequency (ω) of the motor (55)” is the fundamental frequency (ω) of the motor (55) detected by the fundamental frequency detector (117).

<Specific Examples of Signal Correlated with Phase Currents of Motor>

Specific examples of the signal correlated with the phase currents (iu, iv, iw) of the motor (55) include (1) a current vector amplitude (Ia), (2) a square value (Ia²) of the current vector amplitude, (3) a phase current amplitude (I), and (4) a phase current effective value (Irms).

The current vector amplitude (Ia) and the square value (Ia²) of the current vector amplitude are examples of a value corresponding to the sum total of the square values of the phase currents (iu, iv, iw) of the three phases of the motor (55). The value corresponding to the sum total of the square values of the phase currents (iu, iv, iw) of the three phases of the motor (55) is an example of a value proportional to an integer power of the magnitude of the phase currents (iu, iv, iw) of the motor (55).

(1) Current Vector Amplitude

The current vector amplitude (Ia) is derived based on the phase currents (iu, iv, iw) of the motor (55). The current vector amplitude (Ia) may be derived based on an α-phase current (iα) and a β-phase current (iβ) obtained by transforming the phase currents (iu, iv, iw) of the motor (55) into a fixed coordinate system. The current vector amplitude (Ia) may be derived based on an M-axis current (iM) and a T-axis current (iT) obtained by coordinate-transforming the phase currents (iu, iv, iw) of the motor (55) at an angle based on the direction of the primary magnetic flux. The current vector amplitude (Ia) may be derived based on a d-axis current (id) and a q-axis current (iq) obtained by coordinate-transforming the phase currents (iu, iv, iw) of the motor (55) at an angle based on the direction of the magnetic pole position. Specifically, the current vector amplitude (Ia) can be expressed by the following equation.

I a = i u 2 + i v 2 + i w 2 = i α 2 + i β 2 = i M 2 + i T 2 = i d 2 + i q 2 [ Math . 1 ]

(2) Square Value of Current Vector Amplitude

The square value (Ia²) of the current vector amplitude is derived based on the phase currents (iu, iv, iw) of the motor (55). The square value (Ia²) of the current vector amplitude may be derived based on an α-phase current (iα) and a β-phase current (iβ) obtained by transforming the phase currents (iu, iv, iw) of the motor (55) into a fixed coordinate system. The square value (Ia²) of the current vector amplitude may be derived based on an M-axis current (iM) and a T-axis current (iT) obtained by coordinate-transforming the phase currents (iu, iv, iw) of the motor (55) at an angle based on the direction of the primary magnetic flux. The square value (Ia²) of the current vector amplitude may be derived based on a d-axis current (id) and a q-axis current (iq) obtained by coordinate-transforming the phase currents (iu, iv, iw) of the motor (55) at an angle based on the direction of the magnetic pole position. Specifically, the square value (Ia²) of the current vector amplitude can be expressed by the following equation.

I a 2 = i u 2 + i v 2 + i w 2 = i α 2 + i β 2 = i M 2 + i T 2 = i d 2 + i q 2 [ Math . 2 ]

(3) Phase Current Amplitude

The phase current amplitude (I) is derived based on one phase current (e.g., U-phase current (iu)) among the phase currents (iu, iv, iw) of the motor (55) and a phase (ωi) of the phase current. The phase (ωi) of the phase current is derived, for example, based on the phase currents (iu, iv, iw) of the motor (55). Specifically, the phase current amplitude (I) can be expressed by the following equation.

I = i u cos ⁢ ω i ⁢ t [ Math . 3 ]

(4) Phase Current Effective Value

The phase current effective value (Irms) is derived based on the phase current amplitude (I). Specifically, the phase current effective value (Irms) can be expressed by the following equation.

I rms = I 2 [ Math . 4 ]

(5) Other

In the above description, the case where the current vector amplitude (Ia) is derived based on the phase currents (iu, iv, iw) of the three phases of the motor (55) has been described as an example, but the current vector amplitude (Ia) may be derived based on phase currents of two phases among the phase currents (iu, iv, iw) of the three phases of the motor (55). The current vector amplitude (Ia) may be derived based on the direct current of the inverter detected by a direct current detector (e.g., shunt resistance, not illustrated) provided in the motor drive device (45). The same applies to the square value (Ia²) of the current vector amplitude.

<Specific Examples of Signal Correlated with Phase Voltage of Motor>

Specific examples of the signal correlated with the phase voltages (Vu, Vv, Vw) of the motor (55) include (1) a voltage vector amplitude (Va), (2) a square value (Va²) of the voltage vector amplitude, (3) a phase voltage amplitude (V), and (4) a phase voltage effective value (Vrms).

The voltage vector amplitude (Va) and the square value (Va²) of the voltage vector amplitude are examples of a value corresponding to the sum total of the square values of the phase voltages (Vu, Vv, Vw) of the three phases of the motor (55). The value corresponding to the sum total of the square values of the phase voltages (Vu, Vv, Vw) of the three phases of the motor (55) is an example of a value proportional to an integer power of the magnitude of the phase voltages (Vu, Vv, Vw) of the motor (55).

(1) Voltage Vector Amplitude

The voltage vector amplitude (Va) is derived based on the phase voltages (Vu, Vv, Vw) of the motor (55). The voltage vector amplitude (Va) may be derived based on an α-phase voltage (Va) and a β-phase voltage (Vβ) obtained by transforming the phase voltages (Vu, Vv, Vw) of the motor (55) into a fixed coordinate system. The voltage vector amplitude (Va) may be derived based on an M-axis voltage (VM) and a T-axis voltage (VT) obtained by coordinate-transforming the phase voltages (Vu, Vv, Vw) of the motor (55) at an angle based on the direction of the primary magnetic flux. The voltage vector amplitude (Va) may be derived based on a d-axis voltage (Vd) and a q-axis voltage (Vq) obtained by coordinate-transforming the phase voltages (Vu, Vv, Vw) of the motor (55) at an angle based on the direction of the magnetic pole position. Specifically, the voltage vector amplitude (Va) can be expressed by the following equation.

V a = v u 2 + v v 2 + v w 2 = v α 2 + v β 2 = v M 2 + v T 2 = v d 2 + v q 2 [ Math . 5 ]

(2) Square Value of Voltage Vector Amplitude

The square value (Va²) of the voltage vector amplitude is derived based on the phase voltages (Vu, Vv, Vw) of the motor (55). The square value (Va²) of the voltage vector amplitude may be derived based on an α-phase voltage (Vα) and a β-phase voltage (Vβ) obtained by transforming the phase voltages (Vu, Vv, Vw) of the motor (55) into a fixed coordinate system. The square value (Va²) of the voltage vector amplitude may be derived based on an M-axis voltage (VM) and a T-axis voltage (VT) obtained by coordinate-transforming the phase voltages (Vu, Vv, Vw) of the motor (55) at an angle based on the direction of the primary magnetic flux. The square value (Va²) of the voltage vector amplitude may be derived based on a d-axis voltage (Vd) and a q-axis voltage (Vq) obtained by coordinate-transforming the phase voltages (Vu, Vv, Vw) of the motor (55) at an angle based on the direction of the magnetic pole position. Specifically, the square value (Va²) of the voltage vector amplitude can be expressed by the following equation.

V a 2 = v u 2 + v v 2 + v w 2 = v α 2 + v β 2 = v M 2 + v T 2 = v d 2 + v q 2 [ Math . 6 ]

(3) Phase Voltage Amplitude

The phase voltage amplitude (V) is derived based on one phase voltage (e.g., U-phase voltage (Vu)) among the phase voltages (Vu, Vv, Vw) of the motor (55) and a phase (ωv) of the phase voltage. The phase (ωv) of the phase voltage is derived, for example, based on the phase voltages (Vu, Vv, Vw) of the motor (55). Specifically, the phase voltage amplitude (V) can be expressed by the following equation.

V = v u cos ⁢ ω v ⁢ t [ Math . 7 ]

(4) Phase Voltage Effective Value

The phase voltage effective value (Vrms) is derived based on the phase voltage amplitude (V). Specifically, the phase voltage effective value (Vrms) can be expressed by the following equation.

V rms = V 2 [ Math . 8 ]

(5) Other

In the above description, the case where the voltage vector amplitude (Va) is derived based on the phase voltages (Vu, Vv, Vw) of the three phases of the motor (55) has been described as an example, but the voltage vector amplitude (Va) may be derived based on phase voltages of two phases among the phase voltages (Vu, Vv, Vw) of the three phases of the motor (55). The same applies to the square value (Va²) of the voltage vector amplitude.

<Specific Examples of Signal Correlated with Power of Motor>

Examples of the signal correlated with the power of the motor (55) include (1) instantaneous power (p), (2) instantaneous imaginary power (q), (3) apparent power (S), (4) active power (P), and (5) reactive power (Q).

(1) Instantaneous Power

The instantaneous power (p) is derived based on the phase currents (iu, iv, iw) of the motor (55) and the phase voltages (Vu, Vv, Vw) of the motor (55). The instantaneous power (p) may be derived based on an α-phase current (iα) and a β-phase current (iβ) obtained by transforming the phase currents (iu, iv, iw) of the motor (55) into a fixed coordinate system, and an α-phase voltage (Va) and a R-phase voltage (Vβ) obtained by transforming the phase voltages (Vu, Vv, Vw) of the motor (55) into a fixed coordinate system. The instantaneous power (p) may be derived based on an M-axis current (iM) and a T-axis current (iT) obtained by coordinate-transforming the phase currents (iu, iv, iw) of the motor (55) at an angle based on the direction of the primary magnetic flux, and an M-axis voltage (VM) and a T-axis voltage (VT) obtained by coordinate-transforming the phase voltages (Vu, Vv, Vw) of the motor (55) at an angle based on the direction of the primary magnetic flux. The instantaneous power (p) may be derived based on a d-axis current (id) and a q-axis current (iq) obtained by coordinate-transforming the phase currents (iu, iv, iw) of the motor (55) at an angle based on the direction of the magnetic pole position, and a d-axis voltage (Vd) and a q-axis voltage (Vq) obtained by coordinate-transforming the phase voltages (Vu, Vv, Vw) of the motor (55) at an angle based on the direction of the magnetic pole position. Specifically, the instantaneous power (p) can be expressed by the following equation.

p = v u ⁢ i u + v v ⁢ i v + v w ⁢ i w = v α ⁢ i α + v β ⁢ i β = v M ⁢ i M + v T ⁢ i T = v d ⁢ i d + v q ⁢ i q [ Math . 9 ]

(2) Instantaneous Imaginary Power

The instantaneous imaginary power (q) is derived based on an α-phase current (iα) and a R-phase current (iβ) obtained by transforming the phase currents (iu, iv, iw) of the motor (55) into a fixed coordinate system, and an α-phase voltage (Vα) and a R-phase voltage (Vβ) obtained by transforming the phase voltages (Vu, Vv, Vw) of the motor (55) into a fixed coordinate system. The instantaneous imaginary power (q) may be derived based on an M-axis current (iM) and a T-axis current (iT) obtained by coordinate-transforming the phase currents (iu, iv, iw) of the motor (55) at an angle based on the direction of the primary magnetic flux, and an M-axis voltage (VM) and a T-axis voltage (VT) obtained by coordinate-transforming the phase voltages (Vu, Vv, Vw) of the motor (55) at an angle based on the direction of the primary magnetic flux. The instantaneous imaginary power (q) may be derived based on a d-axis current (id) and a q-axis current (iq) obtained by coordinate-transforming the phase currents (iu, iv, iw) of the motor (55) at an angle based on the direction of the magnetic pole position, and a d-axis voltage (Vd) and a q-axis voltage (Vq) obtained by coordinate-transforming the phase voltages (Vu, Vv, Vw) of the motor (55) at an angle based on the direction of the magnetic pole position. Specifically, the instantaneous imaginary power (q) can be expressed by the following equation.

q = v α ⁢ i β - v β ⁢ i α = v M ⁢ i T - v T ⁢ i M = v d ⁢ i q - v q ⁢ i d [ Math . 10 ]

(3) Apparent Power

The apparent power (S) is derived based on the phase voltage effective value (Vrms) and the phase current effective value (Irms). Specifically, the apparent power (S) can be expressed by the following equation.

S = 3 ⁢ V rms ⁢ I rms [ Math . 11 ]

(4) Active Power

The active power (P) is derived based on the phase voltage effective value (Vrms), the phase current effective value (Irms), and a phase difference (φ1) between the phase voltage and the phase current. The phase difference (φ1) between the phase voltage and the phase current is a phase difference between one phase voltage (e.g., U-phase voltage (Vu)) and one phase current (e.g., U-phase current (iu)), and is derived based on the phase (ωi) of the phase current and the phase (ωv) of the phase voltage. Specifically, the active power (P) can be expressed by the following equation.

P = 3 ⁢ V rms ⁢ I rms ⁢ cos ⁢ φ 1 [ Math . 12 ]

(5) Reactive Power

The reactive power (Q) is derived based on the phase voltage effective value (Vrms), the phase current effective value (Irms), and the phase difference (φ1) between the phase voltage and the phase current. The phase difference (φ1) between the phase voltage and the phase current is a phase difference between the U-phase voltage (Vu) and the U-phase current (iu), and is derived based on the phase (ωi) of the phase current and the phase (ωv) of the phase voltage. Specifically, the reactive power (Q) can be expressed by the following equation.

Q = - 3 ⁢ V rms ⁢ I rms ⁢ sin ⁢ φ 1 [ Math . 13 ]

<Currents Obtained by Coordinate-transforming Phase Currents with Phase of Phase Currents>

The currents (iγ, iδ) obtained by coordinate-transforming the phase currents (iu, iv, iw) of the motor (55) with the phase (wi·t) of the phase currents (iu, iv, iw) of the motor (55) can be expressed by the following equation.

[ i γ i δ ] = k [ cos ⁢ ω i ⁢ t cos ⁢ ( ω i ⁢ t - 2 3 ⁢ π ) cos ⁢ ( ω i ⁢ t - 4 3 ⁢ π ) - sin ⁢ ω i ⁢ t - sin ⁢ ( ω i ⁢ t - 2 3 ⁢ π ) - sin ⁢ ( ω i ⁢ t - 4 3 ⁢ π ) ] [ i u i v i w ] [ Math . 14 ]

<Voltages Obtained by Coordinate-transforming Phase Voltages with Phase of Phase Voltages>

The voltages (Vγ, Vδ) obtained by coordinate-transforming the phase voltages (Vu, Vv, Vw) of the motor (55) with the phase (ωv·t) of the phase voltages (Vu, Vv, Vw) of the motor (55) can be expressed by the following equation.

[ v γ v δ ] = k [ cos ⁢ ω v ⁢ t cos ⁢ ( ω v ⁢ t - 2 3 ⁢ π ) cos ⁢ ( ω v ⁢ t - 4 3 ⁢ π ) - sin ⁢ ω v ⁢ t - sin ⁢ ( ω v ⁢ t - 2 3 ⁢ π ) - sin ⁢ ( ω v ⁢ t - 4 3 ⁢ π ) ] [ v u v v v w ] [ Math . 15 ]

<Currents Obtained by Coordinate-transforming Phase Currents with Phase of Phase Voltages>

The currents (iζ, iη) obtained by coordinate-transforming the phase currents (iu, iv, iw) of the motor (55) with the phase (ωv·t) of the phase voltages (Vu, Vv, Vw) of the motor (55) can be expressed by the following equation.

[ i ζ i η ] = k [ cos ⁢ ω v ⁢ t cos ⁢ ( ω v ⁢ t - 2 3 ⁢ π ) cos ⁢ ( ω v ⁢ t - 4 3 ⁢ π ) - sin ⁢ ω v ⁢ t - sin ⁢ ( ω v ⁢ t - 2 3 ⁢ π ) - sin ⁢ ( ω v ⁢ t - 4 3 ⁢ π ) ] [ i u i v i w ] [ Math . 16 ]

<Voltages Obtained by Coordinate-transforming Phase Voltages with Phase of Phase Currents>

The voltages (Vζ, Vη) obtained by coordinate-transforming the phase voltages (Vu, Vv, Vw) of the motor (55) with the phase (ωi·t) of the phase currents (iu, iv, iw) of the motor (55) can be expressed by the following equation.

[ v ζ v η ] = k [ cos ⁢ ω i ⁢ t cos ⁢ ( ω i ⁢ t - 2 3 ⁢ π ) cos ⁢ ( ω i ⁢ t - 4 3 ⁢ π ) - sin ⁢ ω i ⁢ t - sin ⁢ ( ω i ⁢ t - 2 3 ⁢ π ) - sin ⁢ ( ω i ⁢ t - 4 3 ⁢ π ) ] [ v u v v v w ] [ Math . 17 ]

<dq-axis Magnetic Fluxes and Magnitude of Armature Flux Linkage Vector>

The dq-axis magnetic fluxes (λd, λq) obtained by performing coordinate transformation in accordance with the armature flux linkage caused by the permanent magnet and the magnitude λ0 of the armature flux linkage vector obtained by combining the armature flux linkage of the permanent magnet and the armature reaction can be expressed by the following equation. In the following equation, “Ld” is a d-axis inductance and “Lq” is a q-axis inductance.

[ λ d λ q ] = [ L d 0 0 L q ] [ i d i q ] + [ Λ a 0 ] [ Math . 18 ] λ 0 = λ d 2 + λ q 2

<Other Examples of Case Where Motor Signal Is Direct-current Signal>

For example, the motor signal may be a direct-current signal obtained by performing three-phase to two-phase transformation on phase currents, phase voltages, line currents, or line voltages of the motor (55) and further performing rotational coordinate transformation thereon. For example, the motor signal (direct-current signal) may be a d-axis current and a q-axis current obtained by performing rotational coordinate transformation on an a-axis current and a β-axis current, which are obtained by performing three-phase to two-phase transformation on phase currents of the motor (55), at an angle based on the direction of the magnetic pole of the rotor of the motor (55). For example, the motor signal (direct-current signal) may be an M-axis current and a T-axis current obtained by performing rotational coordinate transformation on an α-axis current and a β-axis current at an angle based on the direction of the primary magnetic flux of the rotor of the motor (55).

For example, the motor signal (direct-current signal) may be power input to the converter of the motor drive device (45), power output from the converter, power output from the direct-current unit, current flowing between the converter and the direct-current unit, current flowing between the direct-current unit and the inverter, or the like.

[Specific Examples of Case where Motor Signal is Alternating-Current Signal]

Examples of the motor signal that is an alternating-current signal include “phase currents (iu, iv, iw) of the motor (55)”, “phase voltages (Vu, Vv, Vw) of the motor (55)”, and “flux linkages (Ψfu, Ψfv, Ψfw) of the respective phases”.

The flux linkages (Ψfu, Ψfv, ‥fw) of the respective phases can be expressed by the following equations.

ψ fu = 2 3 ⁢ λ 0 ⁢ cos ⁢ θ [ Math . 19 ] ψ fv = 2 3 ⁢ λ 0 ⁢ cos ⁢ ( θ - 2 3 ⁢ π ) ψ fw = 2 3 ⁢ λ 0 ⁢ cos ⁢ ( θ + 2 3 ⁢ π )

Another example of the case where the motor signal is an alternating-current signal is current and voltage flux linkages of a fixed coordinate obtained by performing three-phase to two-phase transformation on the alternating-current signal.

For example, the motor signal (alternating-current signal) may be phase currents, phase voltages, line currents, line voltages, or the like of the motor (55). For example, the motor signal (alternating-current signal) may be alternating currents of two phases (e.g., α-axis current and β-axis current) or alternating-current voltages of two phases obtained by performing three-phase to two-phase transformation on phase currents, phase voltages, line currents, or line voltages. For example, the alternating current may be current flowing between a commercial power source system (specifically, the alternating-current power source (47)) and the converter of the motor drive device (45).

In Embodiment 7, the first frequency component I of the motor signal has been described as an example of the index I indicating the waveform of the motor signal, but the index I indicating the waveform of the motor signal is not limited thereto. For example, the index I indicating the waveform of the motor signal may be a value obtained by integrating, for one rotation of the motor (55), the absolute value of a value ((Iinst−Iavg)/Iavg) obtained by subtracting an average value Iavg of the motor signal (direct-current signal) for one rotation of the motor (55) from an instantaneous value Iinst of the motor signal (direct-current signal) and dividing the resultant value by the average value Iavg of the motor signal (direct-current signal) for one rotation of the motor (55). As in the case of the first frequency component I of the motor signal, when the amount of the lubricating oil for sealing the compression chamber (61) decreases, this value also decreases as compared to the normal state (the normal state in which poor lubrication does not occur on each sliding portion of the compressor (50)).

Modification 1 of Embodiment 7

Modification 1 is obtained by changing the predictive sign condition in Embodiment 7. In Modification 1, the predictive sign condition is a condition that a decrease rate Ir ((In −I)/In) of the first frequency component I of the motor signal with respect to a predetermined normal value In is greater than or equal to a determination reference value Ib (e.g., 0.1 (10%)) (Ir≥Ib).

The failure prediction unit (23) obtains the first frequency component I of the motor signal as in Embodiment 7, and then calculates the decrease rate Ir of the first frequency component I of the motor signal with respect to the predetermined normal value In. The failure prediction unit (23) calculates the decrease rate Ir by subtracting the first frequency component I of the motor signal from the normal value In and dividing the resultant value by the normal value In. Then, the failure prediction unit (23) compares the calculated decrease rate Ir with the determination reference value Ib, and determines that the predictive sign condition is satisfied when the decrease rate Ir is greater than or equal to the determination reference value Ib (Ir≥Ib).

As described above, in the determination operation, even when the target to be compared to the determination reference value Ib is the decrease rate Ir ((In −I)/In) of the first frequency component I of the motor signal with respect to the predetermined normal value In, effects similar to those of Embodiment 7 can be attained.

Embodiment 8

An air conditioner (10) according to Embodiment 8 is different from the air conditioner (10) according to Embodiment 1 in that a pressure sensor (112) that detects the internal pressure of the compression chamber (61) is provided instead of the temperature sensor (111) that detects the temperature of the discharge gas, and the determination operation performed by the failure prediction unit (23) is changed. The other configurations and operations are similar to those of Embodiment 1. Here, differences from Embodiment 1 will be described.

<Pressure Sensor>

As illustrated in FIG. 4, the pressure sensor (112) is embedded in the compression section (60) so as to be able to detect the internal pressure of the compression chamber (61) of the compressor (50). A plurality of pressure sensors (112) are provided so as to be able to detect the internal pressure of the compression chamber (61) from the start of suction to the end of discharge. The pressure sensor (112) detects the internal pressure of the compression chamber (61), converts the detected internal pressure into an electric signal, and outputs the electric signal to the main controller (21).

<Determination Operation>

A determination operation of the failure prediction unit (23) will be described below. Also in this embodiment, the failure prediction unit (23) repeatedly performs a determination operation of determining whether a predictive sign condition is satisfied every predetermined period (e.g., every 30 seconds). In this embodiment, the predictive sign condition is a condition that a decrease amount ΔTc (Tcn−Tc) of an index T indicating the waveform of a signal (compression torque signal) indicating the compression torque of the compressor (50) with respect to a predetermined normal value Tcn is greater than or equal to a determination reference value Tcb (ΔTc≥Tcb). In Embodiment 8, an example in which a rotation frequency component Tc of the motor (55) is used as the index T indicating the waveform of the compression torque signal will be described.

Here, “the compression torque of the compressor (50)” refers to a value obtained by subtracting a loss such as friction from a load torque required to rotate the compressor (50), that is, a gas compression torque required to compress gas (refrigerant).

First, the failure prediction unit (23) calculates the compression torque while each of the suction, compression, and discharge processes is performed in the compressor (50), and obtains the rotation frequency component Tc of the motor (55) in the signal (compression torque signal) indicating the compression torque. The failure prediction unit (23) calculates the compression torque by integrating a tangential component Fpt perpendicular to the radial component of the force acting in the eccentric direction of the drive shaft (80) by the compression gas (refrigerant) with the orbiting radius r of the drive shaft (80).

The tangential component Fpt perpendicular to the radial component of the force acting in the eccentric direction of the drive shaft (80) by the compression gas (refrigerant) can be expressed by the following equation. In the following equation, “Pi” is the internal pressure of the i-th compression chamber (61) from the center, “h” is the height of the wraps (72, 76), “Ps” is the suction pressure, “Pd” is the discharge pressure, “λpi” is the involute angle of the i-th compression chamber (61), “a” is the radius of the base circle of the involute, and “t” is the thickness of the wraps (72, 76).

Fpt = ah ⁢ { ( Pd - Ps ) ⁢ ( 2 ⁢ λ ⁢ p ⁢ 1 + π + t a ) + 4 ⁢ π ⁢ ∑ i = 2 n ( Pi - Ps ) [ Math . 20 ] Pi = Ps ⁡ ( 2 ⁢ ( 1 + t ε ) ⁢ ( λ ⁢ m ⁢ 0 - π ) + π 2 ⁢ ( 1 + t ε ) ⁢ ( λ ⁢ pi - π ) + π ) κ

Next, the failure prediction unit (23) calculates the decrease amount ΔTc of the rotation frequency component Tc of the motor (55) in the compression torque signal with respect to the predetermined normal value Tcn. The normal value Tcn is a rotation frequency component of the motor (55) in the compression torque signal in a normal state in which poor lubrication does not occur on each sliding portion of the compressor (50), and the failure prediction unit (23) stores a reference value as the normal value Tcn. The failure prediction unit (23) calculates the decrease amount ΔTc by subtracting the normal value Tcn from the rotation frequency component Tc of the motor (55) in the compression torque signal. For example, the normal value Tcn may be a value determined in advance for each type of the compressor (50). For example, a test operation may be performed after installation of the compressor system (40), the rotation frequency component of the motor (55) in the compression torque signal in the normal state in which poor lubrication does not occur on each sliding portion of the compressor (50) may be obtained, and the obtained value may be used as the normal value Tcn. The normal value Tcn is determined for each of operation conditions of the compressor (50) composed of the number of revolutions, the high pressure, and the low pressure.

Next, the failure prediction unit (23) compares the calculated decrease amount ΔTc with the determination reference value Tcb. The failure prediction unit (23) stores a reference value as the determination reference value Tcb. When the decrease amount ΔTc is greater than or equal to the determination reference value Tcb (ΔTc≥Tcb), the failure prediction unit (23) determines that the predictive sign condition is satisfied. That is, the failure prediction unit (23) according to this embodiment determines that the predictive sign condition is satisfied when the decrease amount ΔTc becomes greater than or equal to the determination reference value Tcb for the first time.

As described above, in Embodiment 8, the failure prediction unit (23) obtains the rotation frequency component Tc of the motor (55) in the compression torque signal, and determines whether the predictive sign condition is satisfied (the presence of a predictive sign of failure of the drive shaft (80) and the first to third bearings (79, 69, 93)) based on the rotation frequency component Tc of the motor (55) in the compression torque signal. In Embodiment 8, the rotation frequency component Tc of the motor (55) in the compression torque signal (an index indicating the operating state of the compression section (60)), which changes in conjunction with the amount of the lubricating oil for sealing the compression chamber (61), is used for the predictive sign condition for the following reason.

In the compressor (50), when the amount of oil or the concentration of the lubricating oil in the oil reservoir (95) decreases, the lubricating state in each sliding portion of the compressor (50) to which the lubricating oil in the oil reservoir (95) is supplied via the oil supply passage (87) shifts from fluid lubrication to mixed lubrication or boundary lubrication. As a result, the drive shaft (80) and the first to third bearings (79, 69, 93) are brought into contact with each other and worn, which leads to seizure or the like, and then a failure may occur on the drive shaft (80) and the first to third bearings (79, 69, 93) (brought into an inoperable state). On the other hand, in the compression section (60), before the lubricating state in each sliding portion shifts from the fluid lubrication to the mixed lubrication or the boundary lubrication, the amount of the lubricating oil for sealing the compression chamber (61) decreases. When the amount of the lubricating oil for sealing the compression chamber (61) decreases, the sealability of the compression chamber (61) deteriorates, and refrigerant leakage occurs in which the refrigerant leaks from the compression chamber (61) with a high internal pressure to the compression chamber (61) with a low internal pressure.

When the refrigerant leaks, the waveform of the internal pressure indicating a variation in the internal pressure of the compression chamber (61) changes, and the gas load (the load applied to the orbiting wrap (77) by the pressure of the gas refrigerant) changes. As a result, the waveform of the signal (compression torque signal) indicating the compression torque of the compressor (50), which is represented by the sum total of the products of “the tangential component of the gas load” of each compression chamber (61) and “the distance between the rotation center and the position of the center of gravity of the compression chamber (61)”, changes. Specifically, when the refrigerant leaks, the rotation frequency component Tc of the motor (55) in the compression torque signal (an example of the index T indicating the waveform of the compression torque signal) decreases as compared to the normal state (the normal state in which poor lubrication does not occur on each sliding portion of the compressor (50)).

In Embodiment 8, attention is paid to the rotation frequency component Tc of the motor (55) in the compression torque signal, which decreases in conjunction with poor sealing due to a decrease in the amount of the lubricating oil for sealing the compression chamber (61), and the rotation frequency component Tc of the motor (55) in the compression torque signal is used to determine the presence of a predictive sign of failure of the drive shaft (80) and the first to third bearings (79, 69, 93). Thus, it is possible to predict a failure by detecting a sign of failure of the drive shaft (80) and the first to third bearings (79, 69, 93) after the amount of the oil in the oil reservoir (95) decreases, which causes a failure of the drive shaft (80) and the first to third bearings (79, 69, 93) of the compressor (50), and before the drive shaft (80) and the first to third bearings (79, 69, 93) are significantly damaged.

As described above, the compressor system (40) and the air conditioner (refrigeration apparatus) (10) according to Embodiment 8 also attain effects similar to those of the compressor system (40) and the air conditioner (refrigeration apparatus) (10) according to Embodiment 1. The rotation frequency component Tc of the motor (55) in the compression torque signal changes in conjunction with a change in the amount of sealing oil for the compression chamber (61), but is not affected by friction between the drive shaft (80) and the first to third bearings (79, 69, 93). Thus, with the rotation frequency component Tc of the motor (55) in the compression torque signal, it is easy to grasp the deterioration of the sealability of the compression chamber (61), and the accuracy of prediction is improved by the rotation frequency component Tc of the motor (55) in the compression torque signal being detected as an index indicating the deterioration of the sealability of the compression chamber (61).

In Embodiment 8, the rotation frequency component Tc of the motor (55) in the compression torque signal has been described as an example of the index Tc indicating the waveform of the compression torque, but the index Tc indicating the waveform of the compression torque is not limited thereto. For example, as the index Tc indicating the waveform of the compression torque, a value obtained by integrating, for one rotation of the motor (55), the absolute value of a value ((Tinst−Tavg)/Tavg) obtained by subtracting an average value Tavg of the compression torque for one rotation of the motor (55) from an instantaneous value Tinst of the compression torque signal and dividing the resultant value by the average value Tavg of the compression torque for one rotation of the motor (55) may be used. As in the case of the rotation frequency component Tc of the motor (55) in the compression torque signal, when the amount of the lubricating oil for sealing the compression chamber (61) decreases, this value also decreases as compared to the normal state (the normal state in which poor lubrication does not occur on each sliding portion of the compressor (50)).

Modification 1 of Embodiment 8

Modification 1 is obtained by changing the predictive sign condition in Embodiment 8. In Modification 1, the predictive sign condition is a condition that a decrease rate Tcr ((Tc−Tcn)/Tcn) of the rotation frequency component Tc of the motor (55) in the compression torque signal with respect to a predetermined normal value Tcn is greater than or equal to a determination reference value Tcb (e.g., 0.1 (10%)) (Tcr≥Tcb).

The failure prediction unit (23) obtains the rotation frequency component Tc of the motor (55) in the compression torque signal as in Embodiment 8, and then calculates the decrease rate Tcr of the rotation frequency component Tc of the motor (55) in the compression torque signal with respect to the predetermined normal value Tcn. The failure prediction unit (23) calculates the decrease rate Tcr by subtracting the normal value Tcn from the rotation frequency component Tc of the motor (55) in the compression torque signal and dividing the resultant value by the normal value Tcn. Then, the failure prediction unit (23) compares the calculated decrease rate Tcr with the determination reference value Tcb, and determines that the predictive sign condition is satisfied when the decrease rate Tcr is greater than or equal to the determination reference value Tcb (Tcr≥Tcb).

As described above, in the determination operation, even when the target to be compared to the determination reference value Tcb is the decrease rate Tcr ((Tc−Tcn)/Tcn) of the rotation frequency component Tc of the motor (55) in the compression torque signal with respect to the predetermined normal value Tcn, effects similar to those of Embodiment 8 can be attained.

Modification 2 of Embodiment 8

Modification 2 is obtained by changing the predictive sign condition in Embodiment 8. In Modification 2, a motor torque signal is used for the predictive sign condition instead of the compression torque signal used in Embodiment 8. That is, in Modification 2, a condition that a decrease amount ΔTc (Tcn−Tc) of a rotation frequency component Tc of the motor (55) in a signal (motor torque signal) indicating the output torque of the motor (55) with respect to a predetermined normal values Tcn is greater than or equal to a determination reference value Tcb (ΔTc≥Tcb) is set as the predictive sign condition. The determination operation is similar to that of Embodiment 8, except that the failure prediction unit (23) calculates, instead of the compression torque, the output torque of the motor (55) while each of the suction, compression, and discharge processes of the compressor (50) is performed, obtains the rotation frequency component Tc of the motor (55) in the signal (motor torque signal) indicating the output torque of the motor (55), and uses the obtained value for the determination. The output torque of the motor (55) can be estimated by various well-known methods.

When the amount of the lubricating oil for sealing the compression chamber (61) decreases, the sealability of the compression chamber (61) deteriorates, and the refrigerant leaks, the output torque of the motor (55) changes similarly to the compression torque. When the refrigerant leaks, the internal pressure of the compression chamber (61) on the low-pressure side decreases as compared to the normal state (the normal state in which poor lubrication does not occur on each sliding portion of the compressor (50)). Thus, the rotation frequency component Tc of the motor (55) in the motor torque signal also decreases. Accordingly, even when the determination operation is performed under the predictive sign condition using the motor torque signal instead of the compression torque signal, effects similar to those of Embodiment 8 can be attained.

Embodiment 9

An air conditioner (10) according to Embodiment 9 is different from the air conditioner (10) according to Embodiment 1 in that a vibration sensor (118) that detects the vibration of the compressor (50) is provided instead of the temperature sensor (111) that detects the temperature of the discharge gas, and the determination operation performed by the failure prediction unit (23) is changed. The other configurations and operations are similar to those of Embodiment 1. Here, differences from Embodiment 1 will be described.

<Vibration Sensor>

As illustrated in FIG. 10, the vibration sensor (118) is attached to the compressor (50) so as to be able to detect the vibration of the compressor (50). The vibration sensor (118) detects the vibration of the compressor (50), converts the detected vibration into an electric signal (vibration signal), and outputs the electric signal to the main controller (21).

<Determination Operation>

A determination operation of the failure prediction unit (23) will be described below. Also in this embodiment, the failure prediction unit (23) repeatedly performs a determination operation of determining whether a predictive sign condition is satisfied every predetermined period (e.g., every 30 seconds). In this embodiment, the predictive sign condition is a condition that a decrease amount ΔVi (Vi−Vin) of an index Vi indicating the waveform of a signal (vibration signal) indicating the vibration of the compressor (50) with respect to a predetermined normal value Vin is greater than or equal to a determination reference value Vib (ΔVi≥Vib). In Embodiment 9, an example in which a rotation frequency component Vi of the motor (55) in the vibration signal is used as the index Vi indicating the waveform of the vibration signal will be described.

First, the failure prediction unit (23) obtains the rotation frequency component Vi of the motor (55) in the vibration signal (the detection signal transmitted from the vibration sensor (118)).

Next, the failure prediction unit (23) calculates the decrease amount ΔVi of the rotation frequency component Vi of the motor (55) in the vibration signal with respect to the predetermined normal value Vin. The normal value Vin is a rotation frequency component of the motor (55) in the vibration signal in a normal state in which poor lubrication does not occur on each sliding portion of the compressor (50), and the failure prediction unit (23) stores a reference value as the normal value Vin. The failure prediction unit (23) calculates the decrease amount ΔVi by subtracting the normal value Vin from the rotation frequency component Vi of the motor (55) in the vibration signal. For example, the normal value Vin may be a value determined in advance for each type of the compressor (50). For example, a test operation may be performed after installation of the compressor system (40), the rotation frequency component of the motor (55) in the vibration signal in the normal state in which poor lubrication does not occur on each sliding portion of the compressor (50) may be obtained, and the obtained value may be used as the normal value Vin. The normal value Vin is determined for each of operation conditions of the compressor (50) composed of the number of revolutions, the high pressure, and the low pressure.

Next, the failure prediction unit (23) compares the calculated decrease amount ΔVi with the determination reference value Vib. The failure prediction unit (23) stores a reference value as the determination reference value Vib. When the decrease amount ΔVi is greater than or equal to the determination reference value Vib (ΔVi≥Vib), the failure prediction unit (23) determines that the predictive sign condition is satisfied. That is, the failure prediction unit (23) according to this embodiment determines that the predictive sign condition is satisfied when the decrease amount ΔVi becomes greater than or equal to the determination reference value Vib for the first time.

As described above, in Embodiment 9, the failure prediction unit (23) obtains the rotation frequency component Vi of the motor (55) in the vibration signal, and determines whether the predictive sign condition is satisfied (the presence of a predictive sign of failure of the drive shaft (80) and the first to third bearings (79, 69, 93)) based on the rotation frequency component Vi of the motor (55) in the vibration signal. In Embodiment 9, the rotation frequency component Vi of the motor (55) in the vibration signal (an index indicating the operating state of the compression section (60)), which changes in conjunction with the amount of the lubricating oil for sealing the compression chamber (61), is used for the predictive sign condition for the following reason.

In the compressor (50), when the amount of oil or the concentration of the lubricating oil in the oil reservoir (95) decreases, the lubricating state in each sliding portion of the compressor (50) to which the lubricating oil in the oil reservoir (95) is supplied via the oil supply passage (87) shifts from fluid lubrication to mixed lubrication or boundary lubrication. As a result, the drive shaft (80) and the first to third bearings (79, 69, 93) are brought into contact with each other and worn, which leads to seizure or the like, and then a failure may occur on the drive shaft (80) and the first to third bearings (79, 69, 93) (brought into an inoperable state). On the other hand, in the compression section (60), before the lubricating state in each sliding portion shifts from the fluid lubrication to the mixed lubrication or the boundary lubrication, the amount of the lubricating oil for sealing the compression chamber (61) decreases. When the amount of the lubricating oil for sealing the compression chamber (61) decreases, the sealability of the compression chamber (61) deteriorates, and refrigerant leakage occurs in which the refrigerant leaks from the compression chamber (61) with a high internal pressure to the compression chamber (61) with a low internal pressure.

When the refrigerant leaks, the waveform of the internal pressure indicating a variation in the internal pressure of the compression chamber (61) changes, and the gas load (the load applied to the orbiting wrap (77) by the pressure of the gas refrigerant) changes. As a result, the waveform of the signal (compression torque signal) indicating the compression torque of the compressor (50), which is represented by the sum total of the products of “the tangential component of the gas load” of each compression chamber (61) and “the distance between the rotation center and the position of the center of gravity of the compression chamber (61)”, changes. Since the waveform of the compression torque signal and the waveform of the vibration signal are in conjunction with each other, when the refrigerant leaks, the rotation frequency component Vi of the motor (55) in the vibration signal (the index Vi indicating the waveform of the vibration signal) decreases.

In Embodiment 9, attention is paid to the rotation frequency component Vi of the motor (55) in the vibration signal, which decreases in conjunction with poor sealing due to a decrease in the amount of the lubricating oil for sealing the compression chamber (61), and the rotation frequency component Vi of the motor (55) in the vibration signal is used to determine the presence of a predictive sign of failure of the drive shaft (80) and the first to third bearings (79, 69, 93). Thus, it is possible to predict a failure by detecting a sign of failure of the drive shaft (80) and the first to third bearings (79, 69, 93) after the amount of the oil in the oil reservoir (95) decreases, which causes a failure of the drive shaft (80) and the first to third bearings (79, 69, 93) of the compressor (50), and before the drive shaft (80) and the first to third bearings (79, 69, 93) are significantly damaged.

As described above, the compressor system (40) and the air conditioner (refrigeration apparatus) (10) according to Embodiment 9 also attain effects similar to those of the compressor system (40) and the air conditioner (refrigeration apparatus) (10) according to Embodiment 1. The rotation frequency component Vi of the motor (55) in the vibration signal changes in conjunction with a change in the amount of sealing oil for the compression chamber (61), but is not affected by friction between the drive shaft (80) and the first to third bearings (79, 69, 93). Thus, with the rotation frequency component Vi of the motor (55) in the vibration signal, it is easy to grasp the deterioration of the sealability of the compression chamber (61), and the accuracy of prediction is improved by the rotation frequency component Vi of the motor (55) in the vibration signal being detected as an index indicating the deterioration of the sealability of the compression chamber (61).

In Embodiment 9, the rotation frequency component Vi of the motor (55) in the vibration signal has been described as an example of the index Vi indicating the waveform of the vibration signal, but the index Vi indicating the waveform of the vibration signal is not limited thereto. For example, as the index Vi indicating the waveform of the vibration signal, a value obtained by integrating, for one rotation of the motor (55), the absolute value of a value ((Vinst−Vavg)/Vavg) obtained by subtracting an average value Vavg of the vibration of the compressor (50) for one rotation of the motor (55) from an instantaneous value Vinst of the vibration signal and dividing the resultant value by the average value Vavg of the vibration for one rotation of the motor (55) may be used. As in the case of the rotation frequency component Vi of the motor (55) in the vibration signal, when the amount of the lubricating oil for sealing the compression chamber (61) decreases, this value also decreases as compared to the normal state (the normal state in which poor lubrication does not occur on each sliding portion of the compressor (50)).

Modification 1 of Embodiment 9

Modification 1 is obtained by changing the predictive sign condition in Embodiment 9. In Modification 1, the predictive sign condition is a condition that a decrease rate Vir ((Vi−Vin)/Vin) of the rotation frequency component Vi of the motor (55) in the vibration signal with respect to a predetermined normal value Vin of the rotation frequency component Vi is greater than or equal to a determination reference value Vib (e.g., 0.1 (10%)) (Vir≥Vib).

The failure prediction unit (23) obtains the rotation frequency component Vi of the motor (55) in the vibration signal as in Embodiment 9, and then calculates the decrease rate Vir of the rotation frequency component Vi of the motor (55) in the vibration signal with respect to the predetermined normal value Vin. The failure prediction unit (23) calculates the decrease rate Vir by subtracting the normal value Vin from the rotation frequency component Vi of the motor (55) in the vibration signal and dividing the resultant value by the normal value Vin. Then, the failure prediction unit (23) compares the calculated decrease rate Vir with the determination reference value Vib, and determines that the predictive sign condition is satisfied when the decrease rate Vir is greater than or equal to the determination reference value Vib (Vir≥Vib).

As described above, in the determination operation, even when the target to be compared to the determination reference value Vib is the decrease rate Vir ((Vi−Vin)/Vin) of the rotation frequency component Vi of the motor (55) in the vibration signal with respect to the predetermined normal value Vin, effects similar to those of Embodiment 9 can be attained.

Modification 2 of Embodiment 9

In Modification 2, the air conditioner (10) according to Embodiment 9 is provided with a microphone (119) that detects the sound (air vibration) generated during the operation of the compressor (50), instead of the vibration sensor (118) that detects the vibration of the compressor (50), and a rotation frequency component Vi of the detection signal (vibration signal) from the microphone (119) is used for the predictive sign condition.

As illustrated in FIG. 11, the microphone (119) is provided at a position at which the sound generated by the compressor (50) can be detected during the operation of the compressor (50). The microphone (119) detects the sound generated by the compressor (50) during the operation of the compressor (50), converts the detected sound into an electric signal (vibration signal), and outputs the electric signal to the main controller (21).

The determination operation is different from that of Embodiment 9 only in that the vibration signal is the detection signal transmitted from the microphone (119), and the other determination operations are similar to those of Embodiment 9, and thus the detailed description thereof will be omitted.

As described above, even when the air conditioner (10) according to Embodiment 9 is provided with the microphone (119) instead of the vibration sensor (118), and the rotation frequency component Vi of the detection signal (vibration signal) from the microphone (119) is used for the predictive sign condition, effects as those of Embodiment 9 can be attained.

Embodiment 10

An air conditioner (10) according to Embodiment 10 is different from the air conditioner (10) according to Embodiment 1 in that the drive shaft (80) and the first to third bearings (79, 69, 93) are made of a metal material, a current detector (116) that detects the input current for driving the motor (55) (hereinafter simply referred to as motor driving current) is provided instead of the temperature sensor (111) that detects the temperature of the discharge gas, and the determination operation performed by the failure prediction unit (23) is changed. The other configurations and operations are similar to those of Embodiment 1. Here, differences from Embodiment 1 will be described.

<Current Detector>

As in Embodiment 7 illustrated in FIG. 8, the current detector (116) is provided in an electric wire (three windings (U-phase, V-phase, and W-phase windings) of the motor (55)) connecting the motor drive device (45) and the compressor (50), and detects phase currents (U-phase current (iu), V-phase current (iv), and W-phase current (iw)) of three phases. The current detector (116) outputs the detected phase currents of the three phases to the main controller (21). The current detector (116) is not necessarily provided, and the phase currents (iu, iv, iw) of the three phases may be derived from the direct current detected by the shunt resistance (not illustrated) provided in the direct-current unit (not illustrated) of the motor drive device (45) and a switching pattern.

<Determination Operation>

A determination operation of the failure prediction unit (23) will be described below. Also in this embodiment, the failure prediction unit (23) repeatedly performs a determination operation of determining whether a predictive sign condition is satisfied every predetermined period (e.g., every 30 seconds). In this embodiment, the predictive sign condition is a condition that an increase amount ΔIh (Ih−Ihn) of a predetermined high-frequency component Ih of the motor driving current (any one of phase currents (iu, iv, iw) of three phases detected by the current detector (116)) with respect to a predetermined normal value Ihn is greater than or equal to a determination reference value Ihb (ΔIh≥Ihb).

First, the failure prediction unit (23) obtains the predetermined high-frequency component Ih of the motor driving current (any one of the phase currents (iu, iv, iw) of the three phases detected by the current detector (116)). The failure prediction unit (23) performs fast Fourier transform on any one of the phase currents (iu, iv, iw) of the three phases detected by the current detector (116), and sets a component of a predetermined multiple of the rotation frequency of the motor (55) among a plurality of decomposed frequency components as the predetermined high-frequency component Ih of the motor driving current.

Next, the failure prediction unit (23) calculates the increase amount ΔIh of the predetermined high-frequency component Ih of the motor driving current with respect to the predetermined normal value Ihn. The normal value Ihn is a predetermined high-frequency component of the motor driving current in a normal state in which poor lubrication does not occur on each sliding portion of the compressor (50), and the failure prediction unit (23) stores a reference value as the normal value Ihn. The failure prediction unit (23) calculates the increase amount ΔIh by subtracting the normal value Ihn from the predetermined high-frequency component Ih of the motor driving current. For example, the normal value Ihn may be a value determined in advance for each type of the compressor (50). For example, a test operation may be performed after installation of the compressor system (40), the predetermined high-frequency component of the motor driving current in the normal state in which the bearings (79, 69, 93) do not deteriorate may be obtained, and the obtained value may be used as the normal value Ihn. The normal value Ihn is determined for each of operation conditions of the compressor (50) composed of the number of revolutions, the high pressure, and the low pressure.

Next, the failure prediction unit (23) compares the calculated increase amount ΔIh with the determination reference value Ihb. The failure prediction unit (23) stores a reference value as the determination reference value Ihb. When the increase amount ΔIh is greater than or equal to the determination reference value Ihb (ΔIh≥Ihb), the failure prediction unit (23) determines that the predictive sign condition is satisfied. That is, the failure prediction unit (23) according to this embodiment determines that the predictive sign condition is satisfied when the increase amount ΔIh becomes greater than or equal to the determination reference value Ihb for the first time.

As described above, in Embodiment 10, the failure prediction unit (23) obtains the predetermined high-frequency component Ih of the motor driving current, and determines whether the predictive sign condition is satisfied (the presence of a predictive sign of failure of the drive shaft (80) and the first to third bearings (79, 69, 93)) based on the predetermined high-frequency component Ih of the motor driving current.

The inventors of the present application have found that the predetermined high-frequency component Ih of the motor driving current increases when foreign matter such as wear particles generated by wear of the sliding portions or carbide generated by the deterioration of the lubricating oil is supplied to the sliding portions of the drive shaft (80) and the first to third bearings (79, 69, 93) made of a metal material, together with the lubricating oil. It has also been found that, when the drive shaft (80) and the first to third bearings (79, 69, 93) are made of a metal material, the predetermined high-frequency component Ih of the motor driving current changes due to the supply of the foreign matter, as compared to the case where the drive shaft (80) and the first to third bearings (79, 69, 93) are made of another material. Thus, in Embodiment 10, the predetermined high-frequency component Ih of the motor driving current (an index indicating the drive state of the motor (55)) is used for the predictive sign condition for the following reason.

In the compressor (50), when the amount of oil or the concentration of the lubricating oil in the oil reservoir (95) decreases, the lubricating state in each sliding portion of the compressor (50) to which the lubricating oil in the oil reservoir (95) is supplied via the oil supply passage (87) shifts from fluid lubrication to mixed lubrication or boundary lubrication. As a result, the drive shaft (80) and the first to third bearings (79, 69, 93) are brought into contact with each other and worn (deteriorate), which leads to seizure or the like, and then a failure may occur on the drive shaft (80) and the first to third bearings (79, 69, 93) (brought into an inoperable state). Also in Embodiment 10, the compressor (50) is configured such that, when the amount of the lubricating oil in the oil reservoir (95) decreases, poor sealing due to a decrease in the amount of the lubricating oil for sealing the compression chamber (61) occurs before poor lubrication occurs on the sliding portions of the drive shaft (80) and the first to third bearings (79, 69, 93). Thus, when the amount of the lubricating oil in the oil reservoir (95) decreases, the sliding portion of the compression section (60) wears before the sliding portions of the drive shaft (80) and the first to third bearings (79, 69, 93) wear. The wear particles (foreign matter) thus generated are supplied to the sliding portions of the drive shaft (80) and the first to third bearings (79, 69, 93) together with the lubricating oil.

In the compressor (50), when the deterioration of the lubricating oil starts, the lubricating oil changes in property to become hard carbide, and the carbide (foreign matter) thus generated is also supplied to the sliding portions of the drive shaft (80) and the first to third bearings (79, 69, 93) together with the lubricating oil. As the deterioration of the lubricating oil progresses, the drive shaft (80) and the first to third bearings (79, 69, 93) eventually fail due to seizure or the like, as in the case of the decrease in the amount of the lubricating oil.

When the first to third bearings (79, 69, 93) are made of a resin material, even when the foreign matter such as wear particles or carbide is supplied to the first to third bearings (79, 69, 93), most of the foreign matter is accommodated in the first to third bearings (79, 69, 93). However, in Embodiment 10, since the first to third bearings (79, 69, 93) are made of a metal material, the wear particles are not accommodated in the first to third bearings (79, 69, 93) and damage both the drive shaft (80) and the first to third bearings (79, 69, 93) (the drive shaft (80) and the first to third bearings (79, 69, 93) deteriorate). As a result, the predetermined high-frequency component Ih of the motor driving current increases as compared to the normal state (the normal state in which poor lubrication does not occur on each sliding portion of the compressor (50)). In Embodiment 10, attention is paid to the predetermined high-frequency component Ih of the motor driving current, and the predetermined high-frequency component Ih of the motor driving current is used to determine the presence of a predictive sign of failure of the drive shaft (80) and the first to third bearings (79, 69, 93). Thus, it is possible to predict a failure by detecting a sign of failure of the drive shaft (80) and the first to third bearings (79, 69, 93) after the state in the compressor (50) changes (after the amount of the oil in the oil reservoir (95) decreases when the foreign matter is wear particles, after the lubricating oil deteriorates when the foreign matter is carbide), which causes a failure of the drive shaft (80) and the first to third bearings (79, 69, 93) of the compressor (50), and before the drive shaft (80) and the first to third bearings (79, 69, 93) are damaged.

In Embodiment 10, the drive shaft (80) and the first to third bearings (79, 69, 93) made of a metal material deteriorate (are damaged by wear particles or carbide generated by poor lubrication occurring earlier on other sliding portions) in conjunction with a change in state in the compressor (50) (a decrease in the amount of the oil in the oil reservoir (95) when the foreign matter is wear particles, or the deterioration of the lubricating oil when the foreign matter is carbide), which causes a failure of the drive shaft (80) and the first to third bearings (79, 69, 93), and change the predetermined high-frequency component Ih of the motor driving current (an index indicating the drive state of the motor (55)). That is, in Embodiment 10, the drive shaft (80) and the first to third bearings (79, 69, 93) made of a metal material are target portions for the prediction of failure, and serve as actualizing portions that deteriorate in conjunction with a change in state in the compressor (50) (a decrease in the amount of the oil in the oil reservoir (95) when the foreign matter is wear particles, deterioration of the lubricating oil when the foreign matter is carbide), which causes a failure, and change a predetermined index (the predetermined high-frequency component Ih of the motor driving current) in conjunction with the deterioration.

As described above, the compressor system (40) and the air conditioner (refrigeration apparatus) (10) according to Embodiment 10 also attain effects similar to those of the compressor system (40) and the air conditioner (refrigeration apparatus) (10) according to Embodiment 1.

Modification 1 of Embodiment 10

Modification 1 is obtained by changing the predictive sign condition in Embodiment 10. In Modification 1, the predictive sign condition is a condition that an increase rate Ihr ((Ih−Ihn)/Ihn) of the predetermined high-frequency component Ih of the motor driving current with respect to a predetermined normal value Ihn is greater than or equal to a determination reference value Ihb (e.g., 0.1 (10%)) (Ihr≥Ihb).

The failure prediction unit (23) obtains the predetermined high-frequency component Ih of the motor driving current as in Embodiment 10, and then calculates the increase rate Ihr of the predetermined high-frequency component Ih of the motor driving current with respect to the predetermined normal value Ihn. The failure prediction unit (23) calculates the increase rate Ihr by subtracting the normal value Ihn from the predetermined high-frequency component Ih of the motor driving current and dividing the resultant value by the normal value Ihn. Then, the failure prediction unit (23) compares the calculated increase rate Ihr with the determination reference value Ihb, and determines that the predictive sign condition is satisfied when the increase rate Ihr is greater than or equal to the determination reference value Ihb (Ihr≥Ihb).

As described above, in the determination operation, even when the target to be compared to the determination reference value Ihb is the increase rate Ihr ((Ih−Ihn)/Ihn) of the predetermined high-frequency component Ih of the motor driving current with respect to the predetermined normal value Ihn, effects similar to those of Embodiment 10 can be attained.

Embodiment 11

An air conditioner (10) according to Embodiment 11 is different from the air conditioner (10) according to Embodiment 1 in that the drive shaft (80) and the first to third bearings (79, 69, 93) are made of a metal material, a current detector (116) that detects the input current for driving the motor (55) (hereinafter simply referred to as motor driving current) is provided instead of the temperature sensor (111) that detects the temperature of the discharge gas, and the determination operation performed by the failure prediction unit (23) is changed. The other configurations and operations are similar to those of Embodiment 1. Here, differences from Embodiment 1 will be described.

<Current Detector>

As in Embodiment 7 illustrated in FIG. 8, the current detector (116) is provided in an electric wire (three windings (U-phase, V-phase, and W-phase windings) of the motor (55)) connecting the motor drive device (45) and the compressor (50), and detects phase currents (U-phase current (iu), V-phase current (iv), and W-phase current (iw)) of three phases. The current detector (116) outputs the detected phase currents of the three phases to the main controller (21). The current detector (116) is not necessarily provided, and the phase currents (iu, iv, iw) of the three phases may be derived from the direct current detected by the shunt resistance (not illustrated) provided in the direct-current unit (not illustrated) of the motor drive device (45) and a switching pattern.

<Determination Operation>

A determination operation of the failure prediction unit (23) will be described below. Also in this embodiment, the failure prediction unit (23) repeatedly performs a determination operation of determining whether a predictive sign condition is satisfied every predetermined period (e.g., every 30 seconds). In this embodiment, the predictive sign condition is a condition that an increase amount ΔIhc (Ihc−Ihcn) of a predetermined harmonic component Ihc of the input current for driving the motor (55) (any one of phase currents (iu, iv, iw) of three phases detected by the current detector (116)) with respect to a predetermined normal value Ihcn is greater than or equal to a determination reference value Ihcb (ΔIhc≥Ihcb).

First, the failure prediction unit (23) obtains the predetermined harmonic component Ihc of the motor driving current (any one of the phase currents (iu, iv, iw) of the three phases detected by the current detector (116)). The failure prediction unit (23) performs fast Fourier transform on any one of the phase currents (iu, iv, iw) of the three phases detected by the current detector (116), and sets a component of a predetermined multiple of the rotation frequency of the motor (55) among a plurality of decomposed frequency components, as the predetermined harmonic component Ihc of the motor driving current.

Next, the failure prediction unit (23) calculates the increase amount ΔIhc of the predetermined harmonic component Ihc of the motor driving current with respect to the predetermined normal value Ihcn. The normal value Ihcn is a predetermined harmonic component of the motor driving current in a normal state in which poor lubrication does not occur on each sliding portion of the compressor (50), and the failure prediction unit (23) stores a reference value as the normal value Ihcn. The failure prediction unit (23) calculates the increase amount ΔIhc by subtracting the normal value Ihcn from the predetermined harmonic component Ihc of the motor driving current. For example, the normal value Ihcn may be a value determined in advance for each type of the compressor (50). For example, a test operation may be performed after installation of the compressor system (40), the predetermined harmonic component of the motor driving current in the normal state in which the bearings (79, 69, 93) do not deteriorate may be obtained, and the obtained value may be used as the normal value Ihcn. The normal value Ihcn is determined for each of operation conditions of the compressor (50) composed of the number of revolutions, the high pressure, and the low pressure.

Next, the failure prediction unit (23) compares the calculated increase amount ΔIhc with the determination reference value Ihcb. The failure prediction unit (23) stores a reference value as the determination reference value Ihcb. When the increase amount ΔIhc is greater than or equal to the determination reference value Ihcb (ΔIhc≥Ihcb), the failure prediction unit (23) determines that the predictive sign condition is satisfied. That is, the failure prediction unit (23) according to this embodiment determines that the predictive sign condition is satisfied when the increase amount ΔIhc becomes greater than or equal to the determination reference value Ihcb for the first time.

As described above, in Embodiment 11, the failure prediction unit (23) obtains the predetermined harmonic component Ihc of the motor driving current, and determines whether the predictive sign condition is satisfied (the presence of a predictive sign of failure of the drive shaft (80) and the first to third bearings (79, 69, 93)) based on the predetermined harmonic component Ihc of the motor driving current.

The inventors of the present application have found that, when the drive shaft (80) and the first to third bearings (79, 69, 93) are made of a metal material, even though the sliding portions of the drive shaft (80) and the first to third bearings (79, 69, 93) are poorly lubricated, the sliding portions are less likely to wear as compared to the case where the first to third bearings (79, 69, 93) are made of a resin material. However, once the wear occurs, the surface immediately becomes rough (deteriorates), the protrusions generated due to the rough surface (deterioration) slide on one another while coming into contact with one another, and the predetermined harmonic component Ihc of the motor driving current increases. The inventors also have found that, in a compact compressor (50), while the value of motor driving current is small and it is difficult to grasp its change, when the drive shaft (80) and the first to third bearings (79, 69, 93) are made of a metal material, the increase in the predetermined harmonic component Ihc of the motor driving current because the protrusions generated due to the rough surface (deterioration) slide on one another while coming into contact with one another is larger than that in the case where the drive shaft (80) and the first to third bearings (79, 69, 93) are made of another material.

In Embodiment 11, using this point, the drive shaft (80) and the first to third bearings (79, 69, 93) are made of a metal material, and the predetermined harmonic component Ihc of the motor driving current (an index indicating the drive state of the motor (55)) is used to determine the presence of a predictive sign of failure of the drive shaft (80) and the first to third bearings (79, 69, 93). Thus, it is possible to predict a failure by detecting a sign of failure of the drive shaft (80) and the first to third bearings (79, 69, 93) after poor lubrication occurs, which causes a failure of the drive shaft (80) and the first to third bearings (79, 69, 93) of the compressor (50), and before the drive shaft (80) and the first to third bearings (79, 69, 93) are significantly damaged.

In Embodiment 11, the drive shaft (80) and the first to third bearings (79, 69, 93) made of a metal material deteriorate (surfaces are roughened) in conjunction with a change in state (poor lubrication) in the compressor (50), which causes a failure of the drive shaft (80) and the first to third bearings (79, 69, 93), and change (increase) the predetermined harmonic component Ihc of the motor driving current (an index indicating the drive state of the motor (55)). That is, in Embodiment 11, the drive shaft (80) and the first to third bearings (79, 69, 93) made of a metal material are target portions for the prediction of failure, and serve as actualizing portions that deteriorate (surfaces are roughened) in conjunction with a change in state (poor lubrication) in the compressor (50), which causes a failure, and change a predetermined index (the predetermined harmonic component Ihc of the motor driving current) in conjunction with the deterioration.

As described above, the compressor system (40) and the air conditioner (refrigeration apparatus) (10) according to Embodiment 11 also attain effects similar to those of the compressor system (40) and the air conditioner (refrigeration apparatus) (10) according to Embodiment 1.

Modification 1 of Embodiment 11

Modification 1 is obtained by changing the predictive sign condition in Embodiment 11. In Modification 1, the predictive sign condition is a condition that an increase rate Ihcr ((Ihc−Ihcn)/Ihcn) of the predetermined harmonic component Ihc of the motor driving current with respect to a predetermined normal value Ihcn is greater than or equal to a determination reference value Ihcb (e.g., 0.1 (10%)) (Ihcr≥Ihcb).

The failure prediction unit (23) obtains the predetermined harmonic component Ihc of the motor driving current as in Embodiment 11, and then calculates the increase rate Ihcr of the predetermined harmonic component Ihc of the motor driving current with respect to the predetermined normal value Ihcn. The failure prediction unit (23) calculates the increase rate Ihcr by subtracting the normal value Ihcn from the predetermined harmonic component Ihc of the motor driving current and dividing the resultant value by the normal value Ihcn. Then, the failure prediction unit (23) compares the calculated increase rate Ihcr with the determination reference value Ihcb, and determines that the predictive sign condition is satisfied when the increase rate Ihcr is greater than or equal to the determination reference value Ihcb (Ihcr≥Ihcb).

As described above, in the determination operation, even when the target to be compared to the determination reference value Ihcb is the increase rate Ihcr ((Ihc−Ihcn)/Ihcn) of the predetermined harmonic component Ihc of the motor driving current with respect to the predetermined normal value Ihcn, effects similar to those of Embodiment 11 can be attained.

Modification 2 of Embodiment 11

Modification 2 is obtained by changing the material of the first to third bearings (79, 69, 93) in Embodiment 11. Specifically, in Modification 2, the first to third bearings (79, 69, 93) are made of a resin material.

The inventors of the present application have found that the first to third bearings (79, 69, 93) made of a resin material have a rough outer peripheral surface (a large number of protrusions formed on the outer peripheral surface at molding and protruding radially outward are only bent while avoiding a tool and are not cut during cutting) even though cutting is performed. Thus, when the sliding portions of the drive shaft (80) and the first to third bearings (79, 69, 93) are poorly lubricated, the large number of soft resin protrusions come into contact with the outer peripheral surface of the drive shaft (80), and the predetermined harmonic component Ihc of the motor driving current increases as compared to the normal state (the normal state in which poor lubrication does not occur on each sliding portion of the compressor (50)).

In Modification 2, using this point, the first to third bearings (79, 69, 93) are made of a resin material, and the predetermined harmonic component Ihc of the motor driving current (an index indicating the drive state of the motor (55)) is used to determine the presence of a predictive sign of failure of the drive shaft (80) and the first to third bearings (79, 69, 93). Thus, it is possible to predict a failure by detecting a sign of failure of the drive shaft (80) and the first to third bearings (79, 69, 93) after the amount of the oil in the oil reservoir (95) decreases, which causes a failure of the drive shaft (80) and the first to third bearings (79, 69, 93) of the compressor (50), and before the drive shaft (80) and the first to third bearings (79, 69, 93) are significantly damaged.

In Modification 2, the sliding portions (the resin protrusions protruding toward the drive shaft (80)) of the first to third bearings (79, 69, 93) made of a resin material, which slide on the drive shaft (80), come into contact with the drive shaft (80) and change (increase) the predetermined harmonic component Ihc (the index indicating the drive state of the motor (55)) of the motor driving current in response to a change in state (poor lubrication) in the compressor (50), which causes a failure of the drive shaft (80) and the first to third bearings (79, 69, 93). That is, in Modification 2, the sliding portions (the resin protrusions protruding toward the drive shaft (80)) of the first to third bearings (79, 69, 93) made of a resin material, which slide on the drive shaft (80), are provided in the compressor mechanism section (100) and serve as actualizing portions that change a predetermined index (the predetermined harmonic component Ihc of the motor driving current) in conjunction with a change in state (poor lubrication) in the compressor (50), which causes a failure of the target portions for the prediction of failure (the drive shaft (80) and the first to third bearings (79, 69, 93)).

As described above, even when the material of the first to third bearings (79, 69, 93) is changed to a resin material, effects similar to those of Embodiment 11 can be attained.

The inventors of the present application have found that, when the sliding portions of the drive shaft (80) and the first to third bearings (79, 69, 93) are poorly lubricated and a large number of soft resin protrusions of the first to third bearings (79, 69, 93) come into contact with the outer peripheral surface of the drive shaft (80), the predetermined harmonic component Ihc of the vibration of the compressor (50) and the sound (air vibration) generated during the operation of the compressor (50) also increases as compared to the normal state (the normal state in which poor lubrication does not occur on each sliding portion of the compressor (50)).

In view of the above, in Modification 2, instead of the predetermined harmonic component Ihc of the motor driving current, the predetermined harmonic component Ihc of the detection signal (vibration signal) of the vibration sensor (118) that detects the vibration of the compressor (50) or the microphone (119) that detects the sound (air vibration) generated during the operation of the compressor (50) may be used to determine the presence of a predictive sign of failure of the drive shaft (80) and the first to third bearings (79, 69, 93).

Embodiment 12

Embodiment 12 will be described. An air conditioner (10) according to this embodiment is different from the air conditioner (10) according to Embodiment 1 in that the oil supply passage (87) is changed. A control system (20) of the air conditioner (10) according to this embodiment performs the same operation as the operation of the control system (20) according to Embodiment 1. The oil supply passage (87) of the compressor (50) according to this embodiment will be described.

<Oil Supply Passage>

As illustrated in FIG. 12, also in Embodiment 12, the oil supply passage (87) includes a main oil supply passage (88) and an auxiliary oil supply passage (89). The main oil supply passage (88) according to Embodiment 12 is configured in a manner similar to the main oil supply passage (88) according to Embodiment 1, and constitutes a first oil supply passage that guides the lubricating oil in the oil reservoir (95), on which the pressure (high pressure) of the refrigerant discharged from the compression chamber (61) acts, to the first to third bearings (79, 69, 93). On the other hand, the auxiliary oil supply passage (89) according to Embodiment 12 is different in configuration from the auxiliary oil supply passage (89) according to Embodiment 1.

Specifically, in Embodiment 12, the auxiliary oil supply passage (89) is formed by an oil supply hole formed over the upper shaft support (65) and the fixed scroll (70), and a tubular member extending from the oil reservoir (95) to the oil supply hole. The oil supply hole is formed such that one end thereof opens in the lower surface of the upper shaft support (65) and the other end thereof opens in the gap between the outer peripheral wall portion (73) of the fixed scroll (70) and the orbiting end plate (76) of the orbiting scroll (75). One end of the tubular member opens in the oil reservoir (95), and the other end thereof is inserted into the oil supply hole. The one end of the tubular member serves as an inlet (89a) of the auxiliary oil supply passage (89).

In Embodiment 12, with such a configuration, the auxiliary oil supply passage (89) guides the lubricating oil in the oil reservoir (95), on which the pressure (high pressure) of the refrigerant discharged from the compression chamber (61) acts, directly to the compression section (60) without passing through the crank chamber (67). The lubricating oil guided to the compression section (60) seals the gap between the fixed scroll (70) and the orbiting scroll (75) (seals the compression chamber (61)). That is, in Embodiment 12, the auxiliary oil supply passage (89) constitutes a second oil supply passage that guides the lubricating oil in the oil reservoir (95), on which the pressure (high pressure) of the refrigerant discharged from the compression chamber (61) acts, directly to the compression section (60).

In Embodiment 12, the inlet (89a) of the auxiliary oil supply passage (second oil supply passage) (89) is located higher than an inlet (88a) of the main oil supply passage (first oil supply passage) (88). Thus, when the amount of the lubricating oil in the oil reservoir (95) decreases and the oil level is lowered, the inlet (89a) of the auxiliary oil supply passage (89) will not be able to reach the lubricating oil before the inlet (88a) of the main oil supply passage (88) will, and the lubricating oil is no longer supplied to the compression chamber (61) via the auxiliary oil supply passage (89). With such a configuration, the compressor (50) according to Embodiment 12 is configured such that, when the amount of the lubricating oil in the oil reservoir (95) decreases, poor sealing due to a decrease in the amount of the lubricating oil for sealing the compression chamber (61) occurs before poor lubrication occurs on the sliding portions of the drive shaft (80) and the first to third bearings (79, 69, 93).

As described above, the compressor system (40) and the air conditioner (refrigeration apparatus) (10) according to Embodiment 12 also attain effects similar to those of the compressor system (40) and the air conditioner (refrigeration apparatus) (10) according to Embodiment 1.

In Embodiment 12, the oil supply passage (87) that supplies the lubricating oil to the first to third bearings (79, 69, 93) and the compression section (60) is divided into two, and merely the heights of the inlets (88a, 89a) of the two oil supply passages (88, 89) are changed. Thus, the compressor (50) can be easily configured such that, when the amount of the lubricating oil in the oil reservoir (95) decreases, poor sealing due to a decrease in the amount of the lubricating oil for sealing the compression chamber (61) occurs before poor lubrication occurs on the sliding portions of the drive shaft (80) and the first to third bearings (79, 69, 93).

Embodiment 13

Embodiment 13 will be described. The air conditioner (10) according to this embodiment is different from the air conditioner (10) according to Embodiment 1 in that the oil supply passage (87) and the oil reservoir (95) are changed. A control system (20) of the air conditioner (10) according to this embodiment performs the same operation as the operation of the control system (20) according to Embodiment 1. Here, the oil supply passage (87) and the oil reservoir (95) of the compressor (50) according to this embodiment will be described.

<Oil Supply Passage>

As illustrated in FIG. 13, also in Embodiment 13, the oil supply passage (87) includes a main oil supply passage (88) and an auxiliary oil supply passage (89). The main oil supply passage (88) according to Embodiment 13 is configured in a manner similar to the main oil supply passage (88) according to Embodiment 1, and constitutes a first oil supply passage that guides the lubricating oil in the oil reservoir (95), on which the pressure (high pressure) of the refrigerant discharged from the compression chamber (61) acts, to the first to third bearings (79, 69, 93). On the other hand, the auxiliary oil supply passage (89) according to Embodiment 13 is different in configuration from the auxiliary oil supply passage (89) according to Embodiment 1.

Specifically, in Embodiment 13, the auxiliary oil supply passage (89) is formed by an oil supply hole formed over the upper shaft support (65) and the fixed scroll (70), and a tubular member extending from the oil reservoir (95) to the oil supply hole therein. The oil supply hole is formed such that one end thereof opens in the lower surface of the upper shaft support (65) and the other end thereof opens in the gap between the outer peripheral wall portion (73) of the fixed scroll (70) and the orbiting end plate (76) of the orbiting scroll (75). One end of the tubular member opens in the oil reservoir (95), and the other end thereof is inserted into the oil supply hole. The one end of the tubular member serves as an inlet (89a) of the auxiliary oil supply passage (89).

In Embodiment 13, with such a configuration, the auxiliary oil supply passage (89) guides the lubricating oil in the oil reservoir (95), on which the pressure (high pressure) of the refrigerant discharged from the compression chamber (61) acts, directly to the compression section (60) without passing through the crank chamber (67). The lubricating oil guided to the compression section (60) seals the gap between the fixed scroll (70) and the orbiting scroll (75) (seals the compression chamber (61)). That is, in Embodiment 13, the auxiliary oil supply passage (89) constitutes a second oil supply passage that guides the lubricating oil in the oil reservoir (95), on which the pressure (high pressure) of the refrigerant discharged from the compression chamber (61) acts, to the compression section (60).

<Oil Reservoir>

In Embodiment 13, the oil reservoir (95) includes a main oil reservoir (first oil reservoir) (96) and an auxiliary oil reservoir (second oil reservoir) (97). The main oil reservoir (96) and the auxiliary oil reservoir (97) are separated by a partition member (98) extending in the vertical direction. The partition member (98) is a plate-shaped member extending upward from the bottom portion of the casing (51) to the vicinity of the lower end of the lower shaft support (90), and partitions the oil reservoir (95) into the main oil reservoir (96) and the auxiliary oil reservoir (97) arranged side by side.

The inlet (88a) of the main oil supply passage (88) is located in the main oil reservoir (96), and the inlet (89a) of the auxiliary oil supply passage (89) is located in the auxiliary oil reservoir (97). The inlet (88a) of the main oil supply passage (88) and the inlet (89a) of the auxiliary oil supply passage (89) are provided at heights at which, when the oil level of the lubricating oil in the oil reservoir (95) falls below the upper end of the partition member (98), the oil level of the lubricating oil in the auxiliary oil reservoir (97) falls below the inlet (89a) of the auxiliary oil supply passage (89) before the oil level of the lubricating oil in the main oil reservoir (96) falls below the inlet (88a) of the main oil supply passage (88). With such a configuration, in Embodiment 13, the inlet (89a) of the auxiliary oil supply passage (89) will not be able to reach the oil level before the inlet (88a) of the main oil supply passage (88) will, under an operation condition in which the amount of the oil in the oil reservoir (95) decreases. With such a configuration, the compressor (50) according to Embodiment 13 is configured such that, when the amount of the lubricating oil in the oil reservoir (95) decreases, poor sealing due to a decrease in the amount of the lubricating oil for sealing the compression chamber (61) occurs before poor lubrication occurs on the sliding portions of the drive shaft (80) and the first to third bearings (79, 69, 93).

As described above, the compressor system (40) and the air conditioner (refrigeration apparatus) (10) according to Embodiment 13 also attain effects similar to those of the compressor system (40) and the air conditioner (refrigeration apparatus) (10) according to Embodiment 1.

In Embodiment 13, the oil supply passage (87) and the oil reservoir (95) that supply the lubricating oil to the first to third bearings (79, 69, 93) and the compression section (60) each are divided into two, and the inlets (88a, 89a) of the two oil supply passages (88, 89) are located in the different oil reservoirs (96, 97). The inlets (88a, 89a) of the two oil supply passages (88, 89) are provided at heights at which, when the amount of the oil in the oil reservoir (95) decreases, the inlet (89a) of the auxiliary oil supply passage (89) will not be able to reach the oil level before the inlet (88a) of the main oil supply passage (88) will. In Embodiment 13, the compressor (50) can be easily configured merely by devising the oil supply passage (87) and the oil reservoir (95) such that, when the amount of the lubricating oil in the oil reservoir (95) decreases, poor sealing due to a decrease in the amount of the lubricating oil for sealing the compression chamber (61) occurs before poor lubrication occurs on the sliding portions of the drive shaft (80) and the first to third bearings (79, 69, 93).

Embodiment 14

Embodiment 14 will be described. An air conditioner (10) according to this embodiment is different from the air conditioner (10) according to Embodiment 1 in that the oil supply passage (87) is changed. A control system (20) of the air conditioner (10) according to this embodiment performs the same operation as the operation of the control system (20) according to Embodiment 1. The oil supply passage (87) of the compressor (50) according to this embodiment will be described.

<Oil Supply Passage>

In Embodiment 14, as in Embodiment 1, the oil supply passage (87) includes a main oil supply passage (88) and an auxiliary oil supply passage (89).

In Embodiment 14, the oil supply passage (87) is configured to supply the lubricating oil in the oil reservoir (95) to the sliding portions of the drive shaft (80) and the first to third bearings (79, 69, 93), and to the compression section (60) at a predetermined oil supply ratio.

The predetermined oil supply ratio is a ratio at which, when the amount of the lubricating oil in the oil reservoir (95) falls below a normal state in which the lubricating oil is constantly supplied to the sliding portions of the drive shaft (80) and the first to third bearings (79, 69, 93), and to the compression section (60) through the oil supply passage (87), the amount of the lubricating oil supplied to the compression section (60) per unit time falls below the required amount of the lubricating oil required to seal the compression chamber (61) per unit time before the amount of the lubricating oil supplied to the sliding portions of the drive shaft (80) and the first to third bearings (79, 69, 93) per unit time falls below the required amount of the lubricating oil required not to cause poor lubrication on the sliding portions of the drive shaft (80) and the first to third bearings (79, 69, 93) per unit time.

Specifically, for example, it is assumed that the required amount of supplied oil not to cause poor lubrication on the sliding portions of the drive shaft (80) and the first to third bearings (79, 69, 93) per unit time is 3× (cc/min), and the required amount of supplied oil required to seal the compression chamber (61) per unit time is 7× (cc/min). For example, it is assumed that, in the oil supply passage (87), the total amount of the lubricating oil supplied to the sliding portions of the drive shaft (80) and the first to third bearings (79, 69, 93), and to the compression section (60) is 16× (cc/min). In such a case, the oil supply passage (87) is designed such that the oil supply passage (87) supplies the lubricating oil in the oil reservoir (95) to the sliding portions of the drive shaft (80) and the first to third bearings (79, 69, 93), and to the compression section (60) at an oil supply ratio of one to one.

When the amount of the lubricating oil in the oil reservoir (95) is lower than the normal state, the lubricating oil is no longer constantly supplied to the sliding portions of the drive shaft (80) and the first to third bearings (79, 69, 93), and to the compression section (60) through the oil supply passage (87), and the total amount of the lubricating oil supplied to the sliding portions of the drive shaft (80) and the first to third bearings (79, 69, 93), and to the compression section (60) decreases (e.g., from 16× (cc/min) to 8× (cc/min)). When the total amount of supplied oil decreases to 8× (cc/min), the amounts of supplied oil to the sliding portions of the drive shaft (80) and the first to third bearings (79, 69, 93), and to the compression section (60) also decrease similarly to the total amount of supplied oil (decrease by 50% in this example), and each amount of supplied oil becomes 4× (cc/min). At this time, at the sliding portions of the drive shaft (80) and the first to third bearings (79, 69, 93), the amount of supplied oil of 4X (cc/min) exceeds the required amount of supplied oil of 3X (cc/min) required not to cause poor lubrication on the sliding portions of the drive shaft (80) and the first to third bearings (79, 69, 93), and hence poor lubrication is not caused. On the other hand, in the compression section (60), the amount of supplied oil of 4X (cc/min) falls below the required amount of supplied oil of 7X (cc/min) required to seal the compression chamber (61), and the compression chamber (61) is no longer sealed.

With such a configuration, in the compressor (50) according to Embodiment 14, when the amount of the lubricating oil in the oil reservoir (95) decreases, poor sealing due to a decrease in the amount of the lubricating oil for sealing the compression chamber (61) occurs before poor lubrication occurs on the sliding portions of the drive shaft (80) and the first to third bearings (79, 69, 93).

As described above, the compressor system (40) and the air conditioner (refrigeration apparatus) (10) according to Embodiment 14 also attain effects similar to those of the compressor system (40) and the air conditioner (refrigeration apparatus) (10) according to Embodiment 1.

In Embodiment 14, the oil supply passage (87) is merely designed to supply the lubricating oil in the oil reservoir (95) to the sliding portions of the drive shaft (80) and the first to third bearings (79, 69, 93), and to the compression section (60) at the predetermined oil supply ratio through the oil supply passage (87). Thus, the compressor (50) can be easily configured such that, when the amount of the lubricating oil in the oil reservoir (95) decreases, poor sealing due to a decrease in the amount of the lubricating oil for sealing the compression chamber (61) occurs before poor lubrication occurs on the sliding portions of the drive shaft (80) and the first to third bearings (79, 69, 93).

Embodiment 15

Embodiment 15 will be described. An air conditioner (10) according to this embodiment is different from the air conditioner (10) according to Embodiment 1 in that the residual oil characteristic of the compressor (50) is changed. A control system (20) of the air conditioner (10) according to this embodiment performs the same operation as the operation of the control system (20) according to Embodiment 1.

In Embodiment 14, the compressor (50) is configured to have a residual oil sliding property with which the period from when the lubricating oil is no longer supplied to the sliding portions of the drive shaft (80) and the first to third bearings (79, 69, 93) through the oil supply passage (87) to when the sliding portions of the drive shaft (80) and the first to third bearings (79, 69, 93) start to be damaged is longer than the period from when the lubricating oil in the oil reservoir (95) is no longer supplied to the compression section (60) through the oil supply passage (87) to when the compression chamber (61) is no longer sealed with the lubricating oil.

The residual oil sliding property can be provided by, for example, reducing the surface roughness of the sliding portions of the drive shaft (80) and the first to third bearings (79, 69, 93), making the first to third bearings (79, 69, 93) with a soft material such as a resin, or forming the sliding portions of the drive shaft (80) and the first to third bearings (79, 69, 93) with a material having a low sliding frictional resistance.

As described above, the compressor system (40) and the air conditioner (refrigeration apparatus) (10) according to Embodiment 15 also attain effects similar to those of the compressor system (40) and the air conditioner (refrigeration apparatus) (10) according to Embodiment 1.

In Embodiment 15, even when the amount of the oil in the oil reservoir (95) decreases and the lubricating oil is no longer supplied to the sliding portions of the drive shaft (80) and the first to third bearings (79, 69, 93), and to the compression section (60), the compression chamber (61) is no longer sealed with the lubricating oil before the sliding portions of the drive shaft (80) and the first to third bearings (79, 69, 93) are damaged. Thus, the index indicating the operating state of the compression section (60) (discharge gas temperature Tdp or the like) changes. Thus, with the compressor system (40), it is possible to predict a failure by detecting a sign of failure of the drive shaft (80) and the bearings (79, 69, 93) after the amount of the oil in the oil reservoir (95) decreases and before the drive shaft (80) and the bearings (79, 69, 93) are damaged due to poor lubrication.

OTHER EMBODIMENTS

In each of the above-described embodiments and modifications, the compressor (50) is constituted of a scroll compressor, but the compressor (50) may be any positive-displacement compressor such as a rotary compressor.

The main controller (prediction device) (21) may predict a failure of a target portion (e.g., compression section (60)) other than the drive shaft (80) and the first to third bearings (79, 69, 93), and perform an avoidance operation of avoiding a failure of the target portion or notify the outside of that there is a predictive sign of failure.

In each of the above-described embodiments and modifications, the failure prediction unit (23) of the main controller (21) may be configured to perform, as the avoidance operation, one of “the operation of changing the operating state of the compressor (50) from the normal state to the lightly loaded state” and “the operation of giving a warning of that there is a predictive sign of damage on the bearings (79, 69, 93)”.

In each of the above-described embodiments and modifications, the main controller (21) constitutes the prediction device including the failure prediction unit (23). However, the prediction device is not limited to the main controller (21). For example, an external device or system of the air conditioner (10), such as a server device or a cloud (cloud computing), may include the failure prediction unit (23) and function as a prediction device that predicts a failure by communicating with the main controller (21) via a communication network.

Although the embodiments and modifications have been described, it should be understood that the embodiments and the details thereof are changeable in various ways without departing from the idea and scope of the claims. The components according to the above-described embodiments, modifications, and other embodiments may be appropriately combined or replaced.

INDUSTRIAL APPLICABILITY

As described above, the present disclosure is useful for a compressor system and a refrigeration apparatus.

REFERENCE SIGNS LIST

• • 10 air conditioner (refrigeration apparatus)
  • 21 main controller (prediction device)
  • 23 failure prediction unit
  • 30 refrigerant circuit
  • 40 compressor system
  • 50 compressor
  • 55 motor
  • 60 compression section
  • 61 compression chamber
  • 68 main bearing portion (bearing)
  • 78 boss portion (bearing)
  • 80 drive shaft
  • 82 main journal portion
  • 83 auxiliary journal portion
  • 85 eccentric shaft portion
  • 87 oil supply passage
  • 88 main oil supply passage (first oil supply passage)
  • 88a inlet
  • 89 auxiliary oil supply passage (second oil supply passage)
  • 89a inlet
  • 91 auxiliary bearing portion (bearing)
  • 95 oil reservoir
  • 96 main oil reservoir (first oil reservoir)
  • 97 auxiliary oil reservoir (second oil reservoir)
  • 98 partition member
  • 100 compressor mechanism section