ROTARY COMPRESSOR AND REFRIGERATION APPARATUS

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of, and claims the benefit of priority from International Application No. PCT/JP2024/023235, filed on Jun. 26, 2024, which claims the benefit of priority from Japanese Patent Application No. 2023-122574, filed on Jul. 27, 2023, the entire contents of each are incorporated herein by reference.

BACKGROUND

Technical Field

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

Background Information

Japanese Unexamined Patent Publication No. 2022-072807 discloses a compressor including a compression mechanism part disposed in a closed container and a drive shaft (shaft) that drives the compression mechanism part. The drive shaft has an oil supply passage extending in an axial direction. An oil supply pump is attached to the lower end of the drive shaft. Oil accumulated in a lower portion of the closed container is supplied through the oil supply passage of the drive shaft to sliding portions of the compression mechanism part using the oil supply pump.

SUMMARY

A first aspect of the present disclosure is directed to a rotary compressor including: a casing having an oil reservoir at its bottom; a compression mechanism housed in the casing; a drive shaft configured to drive the compression mechanism into rotation; and an oil pump configured to suck up oil from the oil reservoir toward a storage space provided at a lower portion of the drive shaft, the rotary compressor including: a first sliding member that slides on an outer circumferential surface of the drive shaft; and a second sliding member that slides on the outer circumferential surface of the drive shaft, the second sliding member being spaced from the first sliding member in an axial direction, the drive shaft having a first oil supply passage including: a first axial passage configured to be offset from a center of rotation of the drive shaft in a radial direction, the first axial passage extending from the storage space in the axial direction; and a first connection passage configured to connect the first axial passage and a sliding surface of the first sliding member, and a second oil supply passage including: a second axial passage configured to be offset from the center of rotation of the drive shaft in the radial direction, the second axial passage extending from the storage space in the axial direction at a position apart from the first axial passage; and a second connection passage configured to connect the second axial passage and a sliding surface of the second sliding member.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a refrigerant circuit diagram illustrating a configuration of a refrigeration apparatus according to an embodiment.

FIG. 2 is a longitudinal sectional view illustrating a configuration of a rotary compressor.

FIG. 3 is a transverse sectional view illustrating a configuration of a first cylinder and a first piston.

FIG. 4 is a transverse sectional view illustrating a configuration of a second cylinder and a second piston.

FIG. 5 is a longitudinal sectional view illustrating configurations of a first oil supply passage and a second oil supply passage.

DETAILED DESCRIPTION OF EMBODIMENT(S)

As illustrated in FIG. 1, a rotary compressor (10) is provided in a refrigeration apparatus (1). The refrigeration apparatus (1) includes a refrigerant circuit (la) filled with a refrigerant. The refrigerant circuit (la) includes the rotary compressor (10), a radiator (3), a decompression mechanism (4), and an evaporator (5). The decompression mechanism (4) is, for example, an expansion valve. The refrigerant circuit (la) performs a vapor compression refrigeration cycle.

The refrigeration apparatus (1) is an air conditioner. The air conditioner may be any of a cooling-only apparatus, a heating-only apparatus, or an air conditioner switchable between cooling and heating. In this case, the air conditioner has a switching mechanism (e.g., a four-way switching valve) configured to switch the direction of circulation of the refrigerant. The refrigeration apparatus (1) may be a water heater, a chiller unit, or a cooling apparatus configured to cool air in an internal space. The cooling apparatus cools the air in an internal space of a refrigerator, a freezer, a container, or the like.

As illustrated in FIG. 2, the rotary compressor (10) includes a casing (11), a drive mechanism (20), and a compression mechanism (30). The drive mechanism (20) and the compression mechanism (30) are housed in the casing (11).

The casing (11) is configured as a vertically long cylindrical closed container. Suction connection pipes (16) pass through, and are fixed to, the barrel of the casing (11). Outlet pipes (15) of an accumulator (not shown) are connected to the respective suction connection pipes (16). A discharge pipe (17) passes through, and is fixed to, an upper portion of the casing (11).

The casing (11) has an oil reservoir (18) at its bottom. The oil reservoir (18) stores oil. The oil is used to lubricate sliding portions of the compression mechanism (30) and a drive shaft (25).

Drive Mechanism

The drive mechanism (20) is housed in the casing (11). The drive mechanism (20) includes a motor (21) and the drive shaft (25). The motor (21) is disposed above the compression mechanism (30). The motor (21) includes a stator (22) and a rotor (23).

The stator (22) is fixed to the inner circumferential surface of the casing (11). The rotor (23) passes through the stator (22) in the up-and-down direction. The drive shaft (25) is fixed inside the axial center of the rotor (23). The drive shaft (25) is driven to rotate together with the rotor (23) when the motor (21) is energized.

The drive shaft (25) is arranged on the axis of the casing (11). A centrifugal oil pump (35) is provided at a lower portion of the drive shaft (25). A suction port (35a) is open to a lower portion of the oil pump (35). A storage space (36) is provided above the oil pump (35) at the lower portion of the drive shaft (25).

A first oil supply passage (60) and a second oil supply passage (70) are formed inside the drive shaft (25). Openings of a first axial passage (61) and a second axial passage (71) closer to the storage space (36) are located radially outward of the edge of the suction port (35a), at which they communicate with the storage space (36).

In the example shown in FIG. 2, the entire opening of each of the first axial passage (61) and the second axial passage (71) closer to the storage space (36) is located radially outward of the edge of the suction port (35a), but is not limited thereto. For example, it is sufficient that at least part of the opening of each of the first axial passage (61) and the second axial passage (71) closer to the storage space (36) be located radially outward of the periphery of the suction port (35a).

As the drive shaft (25) rotates, the oil pump (35) sucks up the oil stored in the oil reservoir (18) toward the storage space (36). The oil stored in the storage space (36) is supplied through the first oil supply passage (60) and the second oil supply passage (70) to the sliding portions of the compression mechanism (30) and the drive shaft (25). The first oil supply passage (60) and the second oil supply passage (70) will be described in detail later.

The drive shaft (25) has a main shaft portion (26) and eccentric portions (29). The eccentric portions (29) include a first eccentric portion (27) and a second eccentric portion (28). The second eccentric portion (28) is axially spaced from the first eccentric portion (27).

An upper portion of the main shaft portion (26) is fixed to the rotor (23) of the motor (21). The first eccentric portion (27) is disposed above the second eccentric portion (28). The axes of the first eccentric portion (27) and the second eccentric portion (28) are eccentric from the axis of the main shaft portion (26) by a predetermined amount.

Part of the main shaft portion (26) above the first eccentric portion (27) is rotatably supported by a front head (31) described later. Part of the main shaft portion (26) below the second eccentric portion (28) is rotatably supported by a rear head (33) described later.

Compression Mechanism

In the example shown in FIG. 2, the compression mechanism (30) is a two-cylinder rotary fluid machine. The compression mechanism (30) is disposed below the motor (21). The compression mechanism (30) includes the front head (31), a middle plate (32), the rear head (33), cylinders (37), and pistons (38). The cylinders (37) include a first cylinder (40) and a second cylinder (50). The pistons (38) include a first piston (45) and a second piston (55).

The front head (31), the first cylinder (40), the middle plate (32), the second cylinder (50), and the rear head (33) are stacked in this order from top to bottom and fixed with fastening bolts (34).

The front head (31) is fixed to the barrel of the casing (11). The front head (31) is stacked on top of the first cylinder (40). The front head (31) is arranged to cover a first cylinder chamber (41) of the first cylinder (40) from above. The main shaft portion (26) of the drive shaft (25) is inserted through a central portion of the front head (31). The front head (31) rotatably supports the drive shaft (25). The front head (31) has a first discharge passage (49) penetrating the front head (31) in the axial direction (see FIG. 3).

The first cylinder (40) is configured as a flat, substantially annular member. As illustrated in FIG. 3, the first cylinder (40) includes the first cylinder chamber (41), a first suction passage (42), and a first blade chamber (43).

The first cylinder chamber (41) is provided in a central portion of the first cylinder (40). The first suction passage (42) extends from the inner wall surface of the first cylinder chamber (41) toward the outside in the radial direction of the first cylinder (40). The first suction passage (42) is open to the outer surface of the first cylinder (40). One of the suction connection pipes (16) is connected to an inlet end of the first suction passage (42). An outlet end of the first suction passage (42) communicates with the first cylinder chamber (41).

The first cylinder chamber (41) houses the first piston (45). The first piston (45) includes a first piston body (46) and a first blade (47). The first piston body (46) is formed in an annular shape. The first eccentric portion (27) of the drive shaft (25) is fitted into the first piston body (46). The first blade (47) extends radially outward from the first piston body (46). The first blade (47) is supported by a pair of first bushes (48). The first blade (47) divides the inside of the first cylinder chamber (41) into a low-pressure chamber and a high-pressure chamber.

The first piston (45) rotates eccentrically in the first cylinder chamber (41) when the drive shaft (25) is driven to rotate. When the volume of the low-pressure chamber gradually increases with the eccentric rotation of the first piston (45), the refrigerant flowing through the associated suction connection pipe (16) is sucked through the first suction passage (42) into the low-pressure chamber.

When the low-pressure chamber is isolated from the first suction passage (42), the isolated space constitutes a high-pressure chamber. The internal pressure of the high-pressure chamber increases as the volume of the high-pressure chamber gradually decreases. When the internal pressure in the high-pressure chamber exceeds a predetermined pressure, the refrigerant in the high-pressure chamber flows out of the compression mechanism (30) through the first discharge passage (49). The high-pressure refrigerant flows upward through the internal space of the casing (11) and passes through a core cut (not shown) of the motor (21) or any other passage. The high-pressure refrigerant that has flowed upward of the motor (21) is transferred to the refrigerant circuit through the discharge pipe (17).

The first blade chamber (43) is located radially outward of the first cylinder chamber (41) and away from the first cylinder chamber (41). The first blade chamber (43) penetrates the first cylinder (40) in the thickness direction of the first cylinder (40). A tip portion of the first blade (47) is housed in the first blade chamber (43). The first blade (47) oscillates in the first blade chamber (43) as the first piston body (46) rotates eccentrically.

As illustrated in FIG. 2, the middle plate (32) is sandwiched between the first cylinder (40) and the second cylinder (50). The middle plate (32) is disposed to cover the first cylinder chamber (41) of the first cylinder (40) from below. The middle plate (32) is disposed to cover a second cylinder chamber (51) of the second cylinder (50) from above.

The second cylinder (50) is formed as a flat and substantially annular member. As illustrated in FIG. 4, the second cylinder (50) includes the second cylinder chamber (51), a second suction passage (52), and a second blade chamber (53).

The second cylinder chamber (51) is provided in a central portion of the second cylinder (50). The second suction passage (52) extends from the inner wall surface of the second cylinder chamber (51) toward the outside in the radial direction of the second cylinder (50). The second suction passage (52) is open to the outer surface of the second cylinder (50). The other suction connection pipe (16) is connected to an inlet end of the second suction passage (52). An outlet end of the second suction passage (52) communicates with the second cylinder chamber (51).

The second cylinder chamber (51) houses the second piston (55). The second piston (55) includes a second piston body (56) and a second blade (57). The second piston body (56) is formed in an annular shape. The second eccentric portion (28) of the drive shaft (25) is fitted into the second piston body (56). The second blade (57) extends radially outward from the second piston body (56). The second blade (57) is supported by a pair of second bushes (58). The second blade (57) divides the inside of the second cylinder chamber (51) into a low-pressure chamber and a high-pressure chamber.

The action of the second piston (55) is substantially the same as the action of the first piston (45), and will not be described below.

The second blade chamber (53) is located radially outward of the second cylinder chamber (51) and away from the second cylinder chamber (51). The second blade chamber (53) penetrates the second cylinder (50) in the thickness direction of the second cylinder (50). A tip portion of the second blade (57) is housed in the second blade chamber (53). The second blade (57) oscillates in the second blade chamber (53) as the second piston body (56) rotates eccentrically.

As illustrated in FIG. 2, the rear head (33) is stacked on the bottom of the second cylinder (50). The rear head (33) is disposed to cover the second cylinder chamber (51) of the second cylinder (50) from below. The main shaft portion (26) of the drive shaft (25) is inserted through a central portion of the rear head (33). The rear head (33) rotatably supports the drive shaft (25). The rear head (33) has a second discharge passage (59) penetrating the rear head (33) in the axial direction (see FIG. 4). When the internal pressure in the high-pressure chamber in the second cylinder chamber (51) exceeds a predetermined pressure, the refrigerant in the high-pressure chamber flows out of the compression mechanism (30) through the second discharge passage (59).

Oil Supply Passage

Centrifugal force is applied to the drive shaft (25) as the compression mechanism (30) is driven and rotates, resulting in an increase in the shaft deflection of the drive shaft (25).

To address this, the inventor of this application has focused on the oil supply passage that is a cause of lower rigidity of the drive shaft (25), and has studied how to increase the rigidity of the drive shaft (25) through improvement in the shape of the oil supply passage.

As illustrated in FIG. 5, the main shaft portion (26) has an upper bearing surface (26a) and a lower bearing surface (26b). The upper bearing surface (26a) is a portion of the main shaft portion (26) above the first eccentric portion (27). The lower bearing surface (26b) is a portion of the main shaft portion (26) below the second eccentric portion (28).

The main shaft portion (26) is rotatably supported by the front head (31) as an upper bearing member and the rear head (33) as a lower bearing member. The front head (31) slides on the upper bearing surface (26a) of the main shaft portion (26). The rear head (33) slides on the lower bearing surface (26b) of the main shaft portion (26).

The first piston (45) slides on the outer circumferential surface of the first eccentric portion (27). The second piston (55) slides on the outer circumferential surface of the second eccentric portion (28).

The first oil supply passage (60) and the second oil supply passage (70) are formed in the drive shaft (25). The first oil supply passage (60) includes the first axial passage (61) and a first connection passage (62). The second oil supply passage (70) includes the second axial passage (71) and a second connection passage (72).

The first axial passage (61) is offset from the center of rotation of the drive shaft (25) in the radial direction, and extends from the storage space (36) in the axial direction. The first connection passage (62) connects the first axial passage (61) and the sliding surface of a first sliding member (65).

The first sliding member (65) slides on the outer circumferential surface of the drive shaft (25). The first sliding member (65) is any one of the front head (31), the rear head (33), the first piston (45), or the second piston (55). In the example shown in FIG. 5, the first sliding member (65) includes the front head (31) and the first piston (45).

The first oil supply passage (60) communicates with at least one of the upper bearing surface (26a) of the main shaft portion (26), the lower bearing surface (26b) of the main shaft portion (26), the outer circumferential surface of the first eccentric portion (27), or the second eccentric portion (28). In the example shown in FIG. 5, the first oil supply passage (60) includes two first connection passages (62). The two first connection passages (62) respectively communicate with the upper bearing surface (26a) of the main shaft portion (26) and the outer circumferential surface of the first eccentric portion (27).

A second sliding member (75) is spaced from the first sliding member (65) in the axial direction. The second sliding member (75) slides on the outer circumferential surface of the drive shaft (25). The second sliding member (75) is any one of the front head (31), the rear head (33), the first piston (45), or the second piston (55) that is different from the first sliding member (65). In the example shown in FIG. 5, the second sliding member (75) includes the second piston (55) and the rear head (33).

The second axial passage (71) is offset from the center of rotation of the drive shaft (25) in the radial direction, and extends from the storage space (36) in the axial direction at a position apart from the first axial passage (61). The second connection passage (72) connects the second axial passage (71) and the sliding surface of the second sliding member (75).

The second oil supply passage (70) communicates with at least one of the upper bearing surface (26a) of the main shaft portion (26), the lower bearing surface (26b) of the main shaft portion (26), the outer circumferential surface of the first eccentric portion (27), or the outer circumferential surface of the second eccentric portion (28) that is different from the surface(s) with which the first oil supply passage (60) communicates. In the example shown in FIG. 5, the second oil supply passage (70) includes two second connection passages (72). The two second connection passages (72) respectively communicate with the lower bearing surface (26b) of the main shaft portion (26) and the outer circumferential surface of the second eccentric portion (28).

The sliding surfaces with which the first oil supply passage (60) and the second oil supply passage (70) communicate are not limited to the configuration shown in FIG. 5. For example, the first oil supply passage (60) and the second oil supply passage (70) may respectively communicate with sliding surfaces other than those shown in FIG. 5.

Here, the length of the first axial passage (61) and the length of the second axial passage (71) differ from each other. In the example shown in FIG. 5, the front head (31) and the first piston (45) which are the first sliding members (65) are disposed above the second piston (55) and the rear head (33) which are the second sliding members (75); therefore, the length of the first axial passage (61) is set to be greater than the length of the second axial passage (71).

Advantages of Embodiment

According to this embodiment, for each of the first oil supply passage (60) and the second oil supply passage (70), a distance from the center of rotation of the drive shaft (25) to the inner wall surface at the point farthest in the radial direction can be ensured, thereby achieving a centrifugal pumping action; and the rigidity of the drive shaft (25) can be increased, thereby reducing the shaft deflection.

Specifically, in the configuration in which the first oil supply passage (60) and the second oil supply passage (70) are offset from the center of rotation of the drive shaft (25) in the radial direction, a centrifugal pumping action similar to that of a single circular axial passage can be obtained by ensuring that the distance from the center of rotation of the drive shaft (25) to the inner wall surface at the point farthest in the radial direction is equivalent to the radius of the circular axial passage. In addition, since the drive shaft (25) includes a solid portion between the first oil supply passage (60) and the second oil supply passage (70), it is possible to improve the rigidity of the drive shaft (25) and reduce the shaft deflection, as compared to the case in which the drive shaft (25) includes a hollow portion at its central portion.

According to this embodiment, at least part of the opening of each of the first axial passage (61) and the second axial passage (71) closer to the storage space (36) is located radially outward of the periphery of the suction port (35a). Accordingly, oil that has been sucked into the storage space (36) through the suction port (35a) of the oil pump (35) can be sucked up by a centrifugal pumping action.

According to this embodiment, oil can be supplied through the first oil supply passage (60) or the second oil supply passage (70) to the upper bearing surface (26a) or the lower bearing surface (26b) of the main shaft portion (26) or the outer circumferential surface of the eccentric portion (29).

According to this embodiment, oil is supplied to the lower bearing surface (26b) of the main shaft portion (26) and the outer circumferential surface of the eccentric portion (29) through the same oil supply passage. The number of the oil supply passages as a whole can thus be reduced, and the rigidity of the drive shaft (25) can be improved.

According to this embodiment, oil is supplied to the upper bearing surface (26a) of the main shaft portion (26) and the outer circumferential surface of the eccentric portion (29) through the same oil supply passage. The number of the oil supply passages as a whole can thus be reduced, and the rigidity of the drive shaft (25) can be improved.

According to this embodiment, oil is supplied to the outer circumferential surface of the first eccentric portion (27) through the first oil supply passage (60), and oil is supplied to the outer circumferential surface of the second eccentric portion (28) through the second oil supply passage (70). Thus, a sufficient amount of oil can be supplied to the outer circumferential surfaces of the first eccentric portion (27) and the second eccentric portion (28).

According to this embodiment, the length of the first axial passage (61) and the length of the second axial passage (71) differ from each other. Thus, for example, in a case in which the first sliding member (65) is located above the second sliding member (75), the shorter length of the second axial passage (71) relative to the length of the first axial passage (61) enables improved rigidity of the drive shaft (25), as compared to a case in which the first axial passage (61) and the second axial passage (71) have the same length.

According to this embodiment, the length of the second axial passage (71) through which oil is supplied to the lower bearing surface (26b) of the main shaft portion (26) is shorter than the length of the first axial passage (61) through which oil is supplied to the upper bearing surface (26a) of the main shaft portion (26). This configuration enables improved rigidity of the drive shaft (25) as compared to the case where the first axial passage (61) and the second axial passage (71) have the same length.

According to this embodiment, the refrigeration apparatus includes the rotary compressor (10) and the refrigerant circuit (la) through which the refrigerant compressed by the rotary compressor (10) flows. It is thus possible to provide the refrigeration apparatus (1) that includes the rotary compressor (10).

OTHER EMBODIMENTS

The embodiment described above may be modified as follows.

In the description of this embodiment, the drive shaft (25) includes the first eccentric portion (27) and the second eccentric portion (28), but is not limited thereto.

For example, the drive shaft (25) may include the main shaft portion (26) and one eccentric portion (29). In this case, for example, the first oil supply passage (60) may communicate with the outer circumferential surfaces of the upper bearing surface (26a) and the lower bearing surface (26b) of the main shaft portion (26), and the second oil supply passage (70) may communicate with the outer circumferential surface of the eccentric portion (29).

The drive shaft (25) may include three eccentric portions (29). In this case, for example, the drive shaft (25) may have the first oil supply passage (60), the second oil supply passage (70), and a third oil supply passage, not shown: the first oil supply passage (60) may communicate with the outer circumferential surface of the first eccentric portion (27); the second oil supply passage (70) may communicate with the outer circumferential surface of the second eccentric portion (28); and the third oil supply passage, not shown, may communicate with the outer circumferential surface of the third eccentric portion.

It will be understood that the embodiments and variations described above can be modified with various changes in form and details without departing from the spirit and scope of the claims. The elements according to the embodiments, the variations thereof, and the other embodiments may be combined and replaced with each other. In addition, the expressions of “first,” “second,” “third,” . . . , in the specification and claims are used to distinguish the terms to which these expressions are given, and do not limit the number and order of the terms.

As can be seen from the foregoing description, the present disclosure is useful for a rotary compressor and a refrigeration apparatus.