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/JP2024/017123, filed on May 8, 2024, which claims the benefit of priority from Japanese Patent Application No. 2023-114698, filed on Jul. 12, 2023, the entire contents of each are incorporated herein by reference.

BACKGROUND

Technical Field

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

Background Information

Japanese Unexamined Patent Publication No. 2021-017849 discloses a compressor including a compression mechanism, a drive shaft, and an electric motor that rotates the drive shaft to drive the compression mechanism. The drive shaft extends in the upward/downward direction. A rotor of the electric motor is provided with gas passages penetrating the rotor in the upward/downward direction. A stator is disposed radially outside the rotor in the electric motor.

SUMMARY

A first aspect of the present disclosure is directed to a compressor. The compressor includes: a compression mechanism; a drive shaft; and an electric motor configured to rotate the drive shaft to drive the compression mechanism. The drive shaft extends in an upward/downward direction, the electric motor includes a rotor coupled to the drive shaft and a stator disposed radially outside the rotor, the rotor includes first gas passages penetrating the rotor in the upward/downward direction, a lid member and a tubular member are disposed above the rotor, the lid member has a plate shape facing open ends of the first gas passages at an upper end of the rotor, the tubular member is located radially outside the first gas passages and extends downward from the lid member, a gap extending in a circumferential direction of the tubular member is formed between a lower end of the tubular member and the upper end of the rotor, and a first space surrounded by the upper end of the rotor, the lid member, and the tubular member and opening radially outward through the gap is formed.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows a refrigeration apparatus (1) of a first embodiment.

FIG. 2 is a front sectional view of a compressor (10) of the first embodiment.

FIG. 3 is a front sectional view of an electric motor (70) of the compressor (10) and its peripheral structure of the first embodiment.

FIG. 4 is a plan view of the electric motor (70) of the first embodiment as viewed from above.

FIG. 5 is a front cross-sectional view of a balance weight (60) of the compressor (10) and its peripheral structure of the first embodiment.

FIG. 6 is a plan view of the balance weight (60) and its peripheral structure of the first embodiment, as viewed from below.

FIG. 7 is a graph of relationship between expansion ratio (h/d) [−] and oil carryover rate (E) [%] according to the first embodiment.

FIG. 8 is equivalent to FIG. 5 and illustrates a second embodiment.

DETAILED DESCRIPTION OF EMBODIMENT(S)

Embodiments of the present disclosure will be described in detail below with reference to the drawings. The present disclosure is not limited to the embodiments shown below, and various changes can be made within the scope without departing from the technical concept of the present disclosure. Since each of the drawings is intended to illustrate the present disclosure conceptually, dimensions, ratios, or numbers may be exaggerated or simplified as necessary for ease of understanding.

First Embodiment

Refrigeration Apparatus

A compressor (10) of a first embodiment will be described below. The compressor (10) is applied to a refrigeration apparatus (1). FIG. 1 illustrates the refrigeration apparatus (1). The refrigeration apparatus (1) includes a refrigerant circuit (la) in which a refrigerant circulates. The refrigerant circuit (la) of the refrigeration apparatus (1) includes a compressor (10), a condenser (a radiator) (2), a decompression mechanism (an expansion mechanism) (3), and an evaporator (4). The decompression mechanism (3) is, for example, an expansion valve or a capillary tube. The refrigerant circuit (la) performs a vapor compression refrigeration cycle. The refrigeration apparatus (1) is applied to, for example, an air conditioner and a cooler.

Compressor

FIG. 2 shows the compressor (10) in a front cross-sectional view. The compressor (10) is a scroll compressor. The compressor (10) includes a casing (20), a compression mechanism (30), a drive shaft (40), a housing (50), a balance weight (60), an electric motor (70), a lower bearing member (80), and an oil pump (90).

Hereinafter, the direction in which the axis of the drive shaft (40) extends is referred to as an axial direction and denoted by (Z). A direction orthogonal to the axis of the drive shaft (40) is referred to as a radial direction and denoted by (R). A side closer to the axis of the drive shaft (40) in the radial direction is referred to as radially inside or inward and denoted by (R1). A side farther from the axis of the drive shaft (40) in the radial direction is referred to as radially outside or outward and denoted by (R2). The direction of rotation of the drive shaft (40) is referred to as a circumferential direction and denoted by (T).

The axial direction of the drive shaft (40) extends in a upward/downward direction. The upward/downward direction is indicated by (Z), as is the axial direction. An upper side in the axial direction (the upward/downward direction) is denoted by (Z1). A lower side in the axial direction (the upward/downward direction) is denoted by (Z2).

The compressor (10) is disposed upright. Inside the casing (20), the compression mechanism (30), the housing (50), the balance weight (60), the electric motor (70), the lower bearing member (80), and the oil pump (90) are disposed in this order from top to bottom. The drive shaft (40) extends in the axial direction (the upward/downward direction) in the casing (20).

Casing

The casing (20) houses the compression mechanism (30), the drive shaft (40), the housing (50), the balance weight (60), the electric motor (70), the lower bearing member (80), and the oil pump (90).

The casing (20) is a cylindrical hermetic container that extends in the axial direction (the upward/downward direction). The casing (20) includes a barrel (21), an upper lid (22), a lower lid (23), and a leg (24). The barrel (21) has a cylindrical shape with both ends in the axial direction (the upward/downward direction) open. The upper lid (22) closes an upper end of the barrel (21). The lower lid (23) closes a lower end of the barrel (21). The leg (24) is provided at the bottom of the lower lid (23) to support the casing (20) on the base.

A suction pipe (25) is connected to the casing (20). The suction pipe (25) penetrates the upper lid (22) of the casing (20) in the axial direction. The suction pipe (25) is connected to the compression mechanism (30). A discharge pipe (26) is connected to the casing (20). The discharge pipe (26) radially passes through the barrel (21) of the casing (20). The discharge pipe (26) opens in an internal space of the casing (20).

A bottom portion (20a) of the casing (20) forms an oil reservoir (27). The oil reservoir (27) stores a lubricant (L). The lubricant (L) is provided to lubricate sliding portions of the compressor (10).

Compression Mechanism

The compression mechanism (30) is provided in the casing (20). The compression mechanism (30) compresses the refrigerant. The refrigerant is a gas. The compression mechanism (30) includes a fixed scroll (31) and a movable scroll (35). The movable scroll (35) meshes with the fixed scroll (31).

The fixed scroll (31) includes a fixed end plate (32), a fixed wrap (33), and an outer peripheral wall (34). The fixed end plate (32) has a disc shape. The fixed wrap (33) is in the shape of a spiral wall that draws an involute curve, and protrudes downward from a lower surface of the fixed end plate (32). The outer peripheral wall (34) surrounds the outer periphery of the fixed wrap (33), and protrudes downward from the lower surface of the fixed end plate (32). A distal end face (lower end face) of the outer peripheral wall (34) is substantially flush with a distal end face (lower end face) of the fixed wrap (33).

The movable scroll (35) is also called an orbiting scroll. The movable scroll (35) is disposed below the fixed scroll (31).

The movable scroll (35) includes a movable end plate (36), a movable wrap (37), and a boss (38). The movable end plate (36) has a disc shape. The movable wrap (37) is in the shape of a spiral wall that draws an involute curve, and protrudes upward from an upper surface of the movable end plate (36). The boss (38) has a cylindrical shape and protrudes downward from the center of a lower surface of the movable end plate (36). A bearing (38a) is fitted inside the inner periphery of the boss (38).

In the compression mechanism (30), the movable wrap (37) of the movable scroll (35) meshes with the fixed wrap (33) of the fixed scroll (31). A compression chamber (C) is formed in a region surrounded by the fixed end plate (32) and the fixed wrap (33) of the fixed scroll (31) and the movable end plate (36) and the movable wrap (37) of the movable scroll (35). The refrigerant is compressed in the compression chamber (C).

The fixed end plate (32) of the fixed scroll (31) has a discharge port (P). The discharge port (P) penetrates the center of the fixed end plate (32) in the axial direction. A discharge chamber (Q) is formed in a region between the fixed scroll (31) and the upper lid (22) of the casing (20). The discharge chamber (Q) communicates with the discharge port (P).

Drive Shaft

The drive shaft (40) extends in the axial direction (the upward/downward direction) in the casing (20). The drive shaft (40) has a main shaft portion (41) and an eccentric shaft portion (42). The eccentric shaft portion (42) is provided at an upper end of the main shaft portion (41). The outer diameter of the eccentric shaft portion (42) is smaller than the outer diameter of the main shaft portion (41). An axis (42a) of the eccentric shaft portion (42) is decentered from an axis (41a) of the main shaft portion (41) by a predetermined distance.

The eccentric shaft portion (42) of the drive shaft (40) is rotatably (slidably) supported by the boss (38) of the movable scroll (35) via the bearing (38a).

Housing

The housing (50) houses a bearing (52a) disposed on an upper side. The housing (50) has a substantially cylindrical shape extending in the axial direction (upward/downward direction). The housing (50) is provided below the movable scroll (35) and above the balance weight (60) in the casing (20). The drive shaft (40) is inserted inside the inner periphery of the housing (50). The outer diameter of an upper portion of the housing (50) is larger than the outer diameter of a lower portion of the housing (50). An outer peripheral surface of the upper portion of the housing (50) is fixed to an inner peripheral surface of the barrel (21) of the casing (20).

A discharge space (A) is formed in the casing (20) below the housing (50). The discharge space (A) is formed in a region between the housing (50) and the electric motor (70). The discharge space (A) communicates with the discharge chamber (Q) through a discharge passage (not shown) formed in the fixed scroll (31) and the housing (50). The discharge space (A) communicates with the discharge pipe (26). The discharge space (A) is filled with a high-pressure refrigerant to be discharged.

The inner diameter of the upper portion of the housing (50) is larger than the inner diameter of the lower portion of the housing (50). A crank chamber (51) is formed radially inside the upper portion of the housing (50) by a recess recessed downward. The crank chamber (51) houses the boss (38) of the movable scroll (35).

A main bearing hole (52) is formed radially inside the lower portion of the housing (50). The main bearing hole (52) penetrates the lower portion of the housing (50) in the axial direction (the upward/downward direction), and communicates with the crank chamber (51). A bearing (52a) is fitted inside the inner periphery of the main bearing hole (52). The main shaft portion (41) of the drive shaft (40) is rotatably (slidably) supported in the main bearing hole (52) of the housing (50) via the bearing (52a).

Balance Weight

The balance weight (60) is provided to cancel out an unbalance force generated by the orbiting motion of the movable scroll (35) of the compression mechanism (30). The balance weight (60) is provided below the housing (50) and above the electric motor (70) in the casing (20). The balance weight (60) is provided on the main shaft portion (41) of the drive shaft (40). The balance weight (60) rotates integrally with the drive shaft (40).

The balance weight (60) protrudes radially outward from the drive shaft (40). The balance weight (60) protrudes from the drive shaft (40) in a direction opposite to the direction in which the eccentric shaft portion (42) is decentered from the main shaft portion (41). The balance weight (60) also extends in the axial direction (the upward/downward direction).

As will be described in detail later, a cover (100) and a lid member (110) are attached to the balance weight (60).

Electric Motor

The electric motor (70) will be described with reference to FIGS. 3 and 4. FIG. 3 is a front sectional view of the electric motor (70) of the compressor (10) and its peripheral structure. FIG. 4 is a plan view of the electric motor (70) as viewed from above in the direction of arrow IV shown in FIG. 3. The electric motor (70) is also referred to as a motor. The electric motor (70) is provided below the balance weight (60) and above the lower bearing member (80) in the casing (20). The electric motor (70) rotates the drive shaft (40) to drive the compression mechanism (30).

The electric motor (70) includes a rotor (71) and a stator (72). The stator (72) is provided with a plurality of coils (73) and an insulator (74).

The rotor (71) is also referred to as a rotor. The rotor (71) is made of metal. The rotor (71) has a cylindrical shape extending in the axial direction (the upward/downward direction). The rotor (71) is coupled to the main shaft portion (41) of the drive shaft (40). The main shaft portion (41) of the drive shaft (40) is inserted inside and fixed to the inner periphery of the rotor (71). The rotor (71) rotates integrally with the drive shaft (40).

The rotor (71) is provided with a plurality of first gas passages (75). The first gas passages (75) penetrate the thick portion of the rotor (71) in the axial direction (the upward/downward direction). In other words, the first gas passages (75) extend in the axial direction (the upward/downward direction) from an upper end to lower end of the rotor (71). The first gas passages (75) are arranged side by side at predetermined intervals in the circumferential direction of the rotor (71).

The stator (72) is also referred to as a stator. The stator (72) is made of metal. The stator (72) has a cylindrical shape extending in the axial direction (the upward/downward direction). The stator (72) is fixed to the inner peripheral surface of the barrel (21) of the casing (20). The stator (72) is disposed radially outside the rotor (71). The stator (72) is disposed to surround the rotor (71) from radially outside. The stator (72) and the rotor (71) are spaced apart from each other by a predetermined distance in the radial direction. The rotor (71) is rotatably inserted inside the inner periphery of into the stator (72).

The stator (72) includes a back yoke (72a) and a plurality of teeth (72b). The back yoke (72a) is formed in a cylindrical shape extending in the axial direction (the upward/downward direction). The teeth (72b) protrude radially inward from an inner peripheral surface of the back yoke (72a). The teeth (72b) are arranged side by side in the circumferential direction at predetermined intervals.

A plurality of core cuts (72d) is provided in an outer periphery (72c) of the back yoke (72a) of the stator (72). The core cuts (72d) extend in the axial direction (the upward/downward direction) from an upper end to lower end of the stator (72). Each of the core cuts (72d) is a groove that opens in an outer peripheral surface of the stator (72) and extends in the axial direction (the upward/downward direction) of the stator (72). The core cut (72d) is recessed radially inward from the outer peripheral surface of the back yoke (72a). The core cuts (72d) are arranged side by side at intervals in the circumferential direction of the stator (72).

A plurality of second gas passages (76) are provided between the outer periphery (72c) of the stator (72) and the inner peripheral surface of the barrel (21) of the casing (20). The second gas passages (76) extend in the axial direction (the upward/downward direction) from the upper end to lower end of the stator (72). The second gas passages (76) are formed by the core cuts (72d). The second gas passages (76) are arranged side by side at intervals in the circumferential direction of the stator (72).

The coils (73) are fixed to the stator (72). The coils (73) correspond to the respective teeth (72b). The coils (73) are wound around the teeth (72b) of the stator (72). The coils (73) are arranged side by side at intervals in the circumferential direction of the stator (72).

A third gas passage (77) is provided between each adjacent pair of coils (73) arranged side by side in the circumferential direction. The third gas passages (77) extend in the axial direction (the upward/downward direction) of the stator (72) from the upper end to lower end of the stator (72). The third gas passages (77) are arranged side by side at intervals in the circumferential direction of the stator (72).

A gap (air gap) formed between the rotor (71) and the stator (72) constitutes a fourth gas passage (78). The fourth gas passage (78) extends in the axial direction (the upward/downward direction) from the upper ends to lower ends of the rotor (71) and the stator (72). The fourth gas passage (78) has an annular shape when viewed in the axial direction (the upward/downward direction). The fourth gas passage (78) is located radially inside the third gas passages (77). The fourth gas passage (78) is located radially outside an outer periphery (71b) of the rotor (71). The outer periphery (71b) of the rotor (71) is an outer peripheral surface of the rotor (71). The outer peripheral surface of the rotor (71) faces radially outward.

The insulator (74) is made of resin. There are two insulators (74). The insulators (74) are arranged above and below the stator (72). The insulators (74) insulate the stator (72) from the coils (73).

Lower Bearing Member

The lower bearing member (80) houses a bearing (81a) disposed on a lower side. The lower bearing member (80) has a substantially cylindrical shape extending in the axial direction (the upward/downward direction). The lower bearing member (80) is provided between the electric motor (70) and the oil reservoir (27) (the bottom portion (20a) of the casing (20)) in the casing (20). The lower bearing member (80) includes a cylindrical portion (81), a protrusion (82), and an oil separation plate (83).

The cylindrical portion (81) has a cylindrical shape. The cylindrical portion (81) houses the main shaft portion (41) of the drive shaft (40). The bearing (81a) is fitted inside the inner periphery of the cylindrical portion (81). The main shaft portion (41) of the drive shaft (40) is rotatably (slidably) supported by the cylindrical portion (81) of the lower bearing member (80) via the bearing (81a).

The protrusion (82) protrudes radially outward from the cylindrical portion (81), and is fixed to the inner peripheral surface of the barrel (21) of the casing (20).

The oil separation plate (83) is fixed to the cylindrical portion (81) and extends in the radial direction and the circumferential direction. The oil separation plate (83) faces the oil reservoir (27). The gas refrigerant flowing through the internal space of the casing (20) contains the lubricant (L) in mist form. When the gas refrigerant containing the lubricant (L) in mist form hits the oil separation plate (83), the gas refrigerant and part of the lubricant (L) are separated from each other, and the separated lubricant (L) falls into the oil reservoir (27).

Oil Pump

The oil pump (90) includes a pump portion (91) and a nozzle portion (92). The pump portion (91) is provided at a lower end of the main shaft portion (41) of the drive shaft (40). The pump portion (91) rotates in synchronization with the drive shaft (40) and reciprocates in synchronization with the drive shaft (40). The nozzle portion (92) is fixed to a lower end of the cylindrical portion (81) of the lower bearing member (80). The nozzle portion (92) is immersed in the lubricant (L) stored in the oil reservoir (27) in the bottom portion (20a) of the casing (20).

The oil pump (90) sucks up the lubricant (L) from the oil reservoir (27). The lubricant (L) is supplied to the sliding portions of the compressor (10) through an oil passage (not shown) inside the drive shaft (40).

The sliding portions of the compressor (10) are between the bearing (38a) in the boss (38) of the movable scroll (35) and the eccentric shaft portion (42) of the drive shaft (40), between the bearing (52a) in the main bearing hole (52) of the housing (50) and the main shaft portion (41) of the drive shaft (40), between the bearing (81a) in the cylindrical portion (81) of the lower bearing member (80) and the main shaft portion (41) of the drive shaft (40), and between the lower surface of the movable scroll (35) and the upper surface of the housing (50).

Cover and Tubular Member

FIG. 5 is a front cross-sectional view of the balance weight (60) of the compressor (10) and its peripheral structure. FIG. 6 is a plan view of the balance weight (60) and its peripheral structure as viewed from below in a direction of arrow VI shown in FIG. 5. In FIG. 5, the coils (73) and the insulator (74) are not shown for the sake of simplicity.

As described above, the balance weight (60) is disposed above the electric motor (70). The balance weight (60) is provided on the main shaft portion (41) of the drive shaft (40). The balance weight (60) rotates integrally with the drive shaft (40).

The balance weight (60) extends over substantially a half of the circumference of the drive shaft (40) and protrudes radially outward from the drive shaft (40). The balance weight (60) also extends in the axial direction (the upward/downward direction).

The cover (100) is provided on the main shaft portion (41) of the drive shaft (40). Specifically, the cover (100) is attached to the balance weight (60) on the drive shaft (40). The cover (100) is formed in a cylindrical shape that has a closed end and opens downward. The cover (100) is provided to suppress agitation of the gas caused by the rotation of the balance weight (60). The cover (100) rotates integrally with the drive shaft (40). The cover (100) includes an upper cover portion (101) and an outer peripheral cover portion (102).

The upper cover portion (101) of the cover (100) is disposed above the balance weight (60). The upper cover portion (101) has a circular plate shape. The upper cover portion (101) covers an upper end (60a) of the balance weight (60) from above.

An outer periphery (60b) of the balance weight (60) is located radially outside the first gas passages (75) in the rotor (71) of the electric motor (70). The outer periphery (60b) of the balance weight (60) is a surface of the balance weight (60) facing radially outside. An outer periphery of the upper cover portion (101) is located radially outside the outer periphery (60b) of the balance weight (60). The outer periphery of the upper cover portion (101) is located radially outside the first gas passages (75) in the rotor (71) of the electric motor (70).

The outer periphery (60b) of the balance weight (60) is located radially inside the outer periphery (71b) of the rotor (71) of the electric motor (70). The upper cover portion (101) of the cover (100) is fixed to the upper end (60a) of the balance weight (60) with a fastening element (61) (e.g., a bolt).

The outer peripheral cover portion (102) of the cover (100) is disposed radially outside the balance weight (60). The outer peripheral cover portion (102) has a cylindrical shape. The outer peripheral cover portion (102) extends downward from the outer periphery of the upper cover portion (101). The upper cover portion (101) and the outer peripheral cover portion (102) are integral with each other.

The outer peripheral cover portion (102) of the cover (100) covers the outer periphery (60b) of the balance weight (60) from radially outside.

An inner peripheral surface of the outer peripheral cover portion (102) is located radially outside the first gas passages (75) in the rotor (71) of the electric motor (70). The outer peripheral cover portion (102) located radially outside the first gas passages (75) in the rotor (71) extends downward from the outer periphery of the upper cover portion (101).

The outer peripheral cover portion (102) is located radially inside the outer periphery (71b) of the rotor (71) of the electric motor (70). The outer peripheral cover portion (102) located radially inside the outer periphery (71b) of the rotor (71) of the electric motor (70) extends downward from the outer periphery of the upper cover portion (101).

The outer peripheral cover portion (102) of the cover (100) extends further downward than a lower end (60c) of the balance weight (60). Hereinafter, a portion of the outer peripheral cover portion (102) of the cover (100) below the lower end (60c) of the balance weight (60) is referred to as a tubular member (103).

The tubular member (103) is part of the outer peripheral cover portion (102) of the cover (100). The tubular member (103) is disposed above an upper end (71a) of the rotor (71) of the electric motor (70). The upper end (71a) of the rotor (71) is also the upper surface of the rotor (71). The upper surface of the rotor (71) faces upward. The tubular member (103) has a cylindrical shape. The tubular member (103) rotates integrally with the drive shaft (40).

The tubular member (103) is located radially outside the first gas passages (75) in the rotor (71) of the electric motor (70) and extends downward from an outer periphery (110a) of a lid member (110) described later (specifically, a position slightly radially outside the outer periphery (110a)).

The tubular member (103) is located radially inside the outer periphery (71b) of the rotor (71) of the electric motor (70) and extends downward from the outer periphery (110a) of the lid member (110) described later (specifically, a position slightly radially outside the outer periphery (110a)).

An outer diameter (D1) of the tubular member (103) is equal to or smaller than an outer diameter (D3) of the rotor (71) of the electric motor (70). Specifically, the outer diameter (D1) of the tubular member (103) is smaller than the outer diameter (D3) of the rotor (71) of the electric motor (70). An inner diameter (D2) of the tubular member (103) is smaller than the outer diameter (D3) of the rotor (71) of the electric motor (70).

A gap (120) is formed between a lower end (103a) of the tubular member (103) and the upper end (71a) of the rotor (71) of the electric motor (70). The lower end (103a) of the tubular member (103) is also the lower end of the outer peripheral cover portion (102) of the cover (100). The gap (120) extends in the circumferential direction over the entire circumference of the tubular member (103).

Lid Member

As shown in FIGS. 5 and 6, the lid member (110) is an annular-shaped plate. The lid member (110) extends in the radial direction and the circumferential direction. The main shaft portion (41) of the drive shaft (40) is inserted in the annular lid member (110). The lid member (110) is disposed above the upper end (71a) of the rotor (71) of the electric motor (70). The lid member (110) is disposed below the balance weight (60). In other words, the balance weight (60) is disposed above the lid member (110).

The lid member (110) covers the lower end (60c) of the balance weight (60) from below. The lid member (110) partitions the space inside the cover (100) in the upward/downward direction. An outer diameter of the lid member (110) is slightly smaller than the inner diameter (D2) of the tubular member (103). The lid member (110) is disposed coaxially with the main shaft portion (41) of the drive shaft (40). In this example, the lower end (60c) of the balance weight (60) is also the lower surface (60d) of the balance weight (60). The lower surface (60d) of the balance weight (60) faces downward.

The lid member (110) is fixed to the lower surface (60d) of the balance weight (60). Specifically, the lid member (110) is fixed to the lower surface (60d) of the balance weight (60) with a fastening element (62) (e.g., a bolt). The lid member (110) rotates integrally with the drive shaft (40).

The outer periphery (110a) of the lid member (110) is located radially outside the first gas passages (75) in the rotor (71) of the electric motor (70). The lid member (110) faces open ends (75a) of the first gas passages (75) at the upper end (71a) of the rotor (71) of the electric motor (70). The open ends (75a) of the first gas passages (75) are outlets of the first gas passages (75).

As described above, the tubular member (103) is located radially outside the first gas passages (75) in the rotor (71) and extends downward from the outer periphery (110a) of the lid member (110) (specifically, from a position slightly radially outside the outer periphery (110a)). The lid member (110) and the tubular member (103) are not integral with each other but are separate from each other. The lid member (110) and the tubular member (103) are slightly spaced apart from each other in the radial direction. The radial gap between the lid member (110) and the tubular member (103) is preferably as small as possible to suitably form a first space (U) described later.

First Space

A first space (U) is formed between the upper end (71a) of the rotor (71) of the electric motor (70) and the lower end (60c) of the balance weight (60). The first space (U) is a space surrounded by the upper end (71a) of the rotor (71) of the electric motor (70), the lid member (110), and the tubular member (103). The first space (U) faces the open ends (75a) of the first gas passages (75) at the upper end (71a) of the rotor (71) of the electric motor (70). The first space (U) opens radially outward toward the stator (72) side through the gap (120) formed between the lower end (103a) of the tubular member (103) and the upper end (71a) of the rotor (71).

A lower end of the first space (U) corresponds to the upper end (71a) of the rotor (71). An upper end of the first space (U) corresponds to the lower surface of the lid member (110). An outer peripheral boundary of the first space (U) corresponds to the inner peripheral surface of the tubular member (103). The gap (120) is located radially outside and near a lower portion of the first space (U). The first space (U) is located below the discharge pipe (26).

It is preferable that a distance (h) between the lower surface of the lid member (110) and the upper end (71a) of the rotor (71) and a distance (d) between the lower end (103a) of the tubular member (103) and the upper end (71a) of the rotor (71) satisfy d≤h/3. The distance (d) corresponds to the vertical dimension of the gap (120).

The distance (d) between the lower end (103a) of the tubular member (103) and the upper end (71a) of the rotor (71), the inner diameter (D2) of the tubular member (103), a total cross-sectional area (M) of all the first gas passages (75), and the circular constant (π) preferably satisfy M/(π×D2)≤d.

The total cross-sectional area (M) is the sum of the cross-sectional areas of all the first gas passages (75). The total cross-sectional area (M) of all the first gas passages (75) is expressed by M=n×B, where (n) is the number of the first gas passages (75), and (B) is the cross-sectional area of each of the first gas passages (75).

The cross-sectional area (S) of the gap (120) between the lower end (103a) of the tubular member (103) and the upper end (71a) of the rotor (71) is expressed by S=π×D2×d, where (d) is the distance between the lower end (103a) of the tubular member (103) and the upper end (71a) of the rotor (71), (D2) is the inner diameter of the tubular member (103), and (π) is the circular constant. When S=π×D2×d is applied to M/(π×D2)≤d, M≤S is satisfied.

Operation of Compressor

An operation of the compressor (10) will be described below. When the electric motor (70) is driven, the drive shaft (40) rotates, and the movable scroll (35) of the compression mechanism (30) is driven. The movable scroll (35) revolves around the axis (41a) of the main shaft portion (41) of the drive shaft (40) while being rotating of the movable scroll (35) is restricted.

A low-pressure gas refrigerant is sucked into the compression chamber (C) of the compression mechanism (30) in the casing (20) through the suction pipe (25), and compressed to be a high-pressure gas refrigerant. The high-pressure gas refrigerant is discharged from the compression chamber (C) to the discharge chamber (Q) through the discharge port (P) of the fixed scroll (31). The high-pressure gas refrigerant flows from the discharge chamber (Q) into the discharge space (A) below the housing (50) through a discharge passage (not shown) formed in the fixed scroll (31) and the housing (50). The high-pressure gas refrigerant is discharged from the discharge space (A) to the outside of the casing (20) (e.g., to the condenser (2) of the refrigerant circuit (la)) through the discharge pipe (26).

Flow of Discharge Gas in Compressor

The flow of the discharge gas (G) in the compressor (10) will be described with reference to FIG. 3. The discharge gas (G) is a gas that is compressed in the compression chamber (C) of the compression mechanism (30) and discharged outside the casing (20). The discharge gas (G) contains the mist-like lubricant (L). The discharge gas (G) compressed in the compression chamber (C) of the compression mechanism (30) is introduced to the second gas passages (76) formed by the core cuts (72d) via the discharge port (P), a passage (not shown) formed in the compression mechanism (30), and a guide member (not shown).

As described above, the second gas passages (76) formed by the core cuts (72d) are provided between the outer periphery (72c) of the stator (72) of the electric motor (70) and the inner peripheral surface of the barrel (21) of the casing (20). The discharge gas (G) flows downward through the second gas passages (76).

The discharge gas (G) having passed through the second gas passages (76) hits the oil separation plate (83) of the lower bearing member (80) and is bounced back. At this time, part of the mist-like lubricant (L) contained in the discharge gas (G) is separated from the discharge gas (G) by the oil separation plate (83), and falls into the oil reservoir (27) in the bottom portion (20a) of the casing (20).

Part of the discharge gas (G) bounced back by the oil separation plate (83) flows into the first gas passages (75) in the rotor (71) of the electric motor (70) from below. The discharge gas (G) flows upward through the first gas passages (75). The discharge gas (G) having passed through the first gas passages (75) is discharged upward from the open ends (75a) of the first gas passages (75) at the upper end (71a) of the rotor (71).

The discharge gas (G) discharged upward from the first gas passages (75) flows out of the first space (U) through the gap (120), which will be described in detail later.

The rest of the discharge gas (G) bounced back by the oil separation plate (83) flows into the third gas passage (77) between each adjacent pair of coils (73) of the electric motor (70) arranged side by side in the circumferential direction and the fourth gas passage (78) between the rotor (71) and the stator (72) from below. The discharge gas (G) flows upward through the third gas passages (77) and the fourth gas passage (78). The discharge gas (G) having passed through the third gas passages (77) and the fourth gas passage (78) is discharged into a space (V) above an upper end (72e) of the stator (72).

Hereinafter, the space (V) above the upper end (72e) of the stator (72) may be referred to as the space (V) above the stator (72) for the sake of simplicity. The space (V) above the stator (72) is part of the discharge space (A) formed between the housing (50) and the electric motor (70) and is located immediately above the upper end (72e) of the stator (72).

Disturbance in Gas Flow

In FIG. 4, a two-dot-dash line schematically shows the flow of the discharge gas (G) discharged from the open ends (75a) of the first gas passages (75) at the upper end (71a) of the rotor (71) of the electric motor (70) when no first space (U) is formed.

As described above, the first gas passages (75) are arranged side by side at predetermined intervals in the circumferential direction of the rotor (71) of the electric motor (70). The discharge gas (G) is discharged upward and radially outward from the open ends (75a) of the first gas passages (75) at the upper end (71a) of the rotor (71) of the electric motor (70). In the rotor (71), passage regions (I) having the first gas passages (75) and non-passage regions (J) having no first gas passages (75) are alternately arranged in the circumferential direction.

In the passage regions (I) of the rotor (71), the flow velocity of the discharge gas (G) discharged upward and radially outward toward the space (V) above the stator (72) is relatively high, and in the non-passage regions (J) of the rotor (71), the flow velocity of the discharge gas (G) discharged upward and radially outward toward the space (V) above the stator (72) is relatively low.

When the rotor (71) rotates in this state, the flow of the discharge gas (G) in the space (V) above the stator (72) is disturbed by the flow of the discharge gas (G) discharged from the open ends (75a) of the first gas passages (75) at the upper end (71a) of the rotor (71).

Specifically, when the rotor (71) is viewed from an arbitrary position (W) in the circumferential direction above the stator (72), the passage regions (I) of the rotor (71) and the non-passage regions (J) of the rotor (71) alternately pass. Thus, the flow velocity of the discharge gas (G) from the rotor (71) side to the stator (72) side constantly varies, whereby the flow velocity of the discharge gas (G) from the rotor (71) side to the stator (72) side increases or decreases.

The variation in the flow velocity of the discharge gas (G) from the rotor (71) side to the stator (72) side affects the discharge gas (G) discharged from the third gas passages (77) and the fourth gas passage (78) to the space (V) above the stator (72), hindering and disturbing the upward flow of the discharge gas (G).

If the discharge gas (G) discharged from the third gas passages (77) and the fourth gas passage (78) into the space (V) above the stator (72) is disturbed, the downward flow of the discharge gas (G) passing through the second gas passages (76) (core cuts (72d)) between the outer periphery (72c) of the stator (72) and the inner peripheral surface of the barrel (21) of the casing (20) is hindered.

If the flow of the discharge gas (G) in the space (V) above the stator (72) is affected by the flow of the discharge gas (G) discharged from the open ends (75a) of the first gas passages (75) at the upper end (71a) of the rotor (71), and the flow of the discharge gas (G) in the space (V) above the stator (72) is disturbed, the flow of the discharge gas (G) flowing inside the compressor (10) is hindered, and the oil carryover cannot be effectively reduced.

The oil carryover is a phenomenon that occurs in the compressor (10), in which the lubricant (L) in the casing (20) is discharged outside the casing (20) (e.g., to the condenser (2) of the refrigerant circuit (la)) through the discharge pipe (26) together with the discharge gas (G). The oil carryover is not preferable because it reduces the amount of the lubricant (L) for lubricating the sliding portions of the compressor (10).

In the compressor (10) according to the present embodiment, the first space (U) formed above the rotor (71) can reduce the disturbance in the flow of the discharge gas (G) in the space (V) above the stator (72) caused by the flow of the discharge gas (G) discharged from the open ends (75a) of the first gas passages (75) at the upper end (71a) of the rotor (71). Further, in the compressor (10) of the present embodiment, the oil carryover can be reduced by reducing the flow disturbance of the discharge gas (G) in the space (V) above the stator (72).

Role of First Space

The role of the first space (U) will be described below. The first space (U) is formed between the upper end (71a) of the rotor (71) and the lower end (60c) of the balance weight (60) and surrounded by the upper end (71a) of the rotor (71), the lid member (110), and the tubular member (103). The first space (U) opens radially outward toward the stator (72) side through the gap (120) formed between the lower end (103a) of the tubular member (103) and the upper end (71a) of the rotor (71).

The discharge gas (G) is discharged upward from the open ends (75a) of the first gas passages (75) at the upper end (71a) of the rotor (71), and is introduced into the first space (U). The discharge gas (G) hits the lid member (110) in the first space (U), thereby suppressing the upward movement of the discharge gas (G). The discharge gas (G) hits the tubular member (103) in the first space (U), thereby suppressing the radially outward movement of the discharge gas (G).

The discharge gas (G) temporarily stays in the first space (U), and then is diffused over the entire circumferential direction. The discharge gas (G) is discharged radially outward from the first space (U) toward the space (V) above the stator (72) outside the first space (U) through the gap (120) between the lower end (103a) of the tubular member (103) and the upper end (71a) of the rotor (71) substantially uniformly over the entire circumferential direction.

As described above, the gap (120) extends over the entire circumference of the tubular member (103). Thus, the flow velocity of the discharge gas (G) that flows out of the first space (U) through the gap (120) is made uniform in the circumferential direction of the tubular member (103). This reduces the influence of the flow of the discharge gas (G) that flows out of the first gas passages (75) on the flow of the discharge gas (G) discharged upward from the third gas passages (77) and the fourth gas passage (78) compared to conventional cases. As a result, the flow disturbance of the discharge gas (G) in the space (V) above the stator (72) of the electric motor (70) is reduced.

Relationship Between Expansion Ratio and Oil Carryover Rate

As described above, the discharge gas (G) discharged upward from the first gas passages (75) in the rotor (71) temporarily stays in the first space (U) to reduce the flow disturbance of the discharge gas (G) in the space (V) above the stator (72). This reduces the flow disturbance of the discharge gas (G) inside the compressor (10), improving the oil carryover rate of the compressor (10). FIG. 7 shows the relationship between the expansion ratio (h/d) [−] and the oil carryover rate (E) [%].

The horizontal axis represents the expansion ratio (h/d). The expansion ratio (h/d) is obtained by dividing the distance (h) between the lower surface of the lid member (110) and the upper end (71a) of the rotor (71) by the distance (d) between the lower end (103a) of the tubular member (103) and the upper end (71a) of the rotor (71).

The vertical axis represents the oil carryover rate (E) [%]. The oil carryover rate (E) is a mass percentage of the lubricant (L) to a mixture of the lubricant (L) and the discharge gas (G) discharged outside the casing (20) through the discharge pipe (26).

The numerical values based on which the graph of FIG. 7 is created are shown below. The following numerical values are merely examples, and numerical values are not necessarily limited to the following numerical values. In the compressor (10) of the present embodiment, the ratio between the numerical values often has the same tendency as that described below although specific numerical values are different from those described below.

The distance (h) between the lower surface of the lid member (110) and the upper end (71a) of the rotor (71) was 15.4 [mm]. The inner diameter (D2) of the tubular member (103) was 76 [mm]. The number (n) of the first gas passages (75) was 6 [passages]. The cross-sectional area (B) of each of the first gas passages (75) was 22.0 [mm²]. The total cross-sectional area (M) of all the first gas passages (75) was 132.0 [mm²](M=n×B).

The conditions of the discharge gas (G) and the lubricant (L) when the graph of FIG. 7 was created are shown below. The following conditions are merely examples, and the present invention is not necessarily limited to the following conditions. R410A was used as the discharge gas (G). A lubricant containing polyvinyl ether-based synthetic base oil as a main component was used as the lubricant (L).

The oil carryover rate (E) was measured for various expansion ratios (h/d) by changing the distance (d) between the lower end (103a) of the tubular member (103) and the upper end (71a) of the rotor (71).

The higher oil carryover rate (E) means undesirable oil carryover. The high (undesirable) oil carryover rate (E) is caused by the disturbance in the flow of the discharge gas (G) inside the compressor (10).

As shown in FIG. 7, in a range where the expansion ratio (h/d) is 5 or less, the oil carryover rate (E) decreases as the expansion ratio (h/d) increases. For example, when the expansion ratio (h/d) is 1 (h=d), the oil carryover rate (E) is about 6 [%]. When the expansion ratio (h/d) is 3, the oil carryover rate (E) is about 2.1 [%]. When the expansion ratio (h/d) is 5, the oil carryover rate (E) is about 1.5 [%].

When the expansion ratio (h/d) is in the range of 5 to 29.8, the oil carryover rate (E) is about 1.5 [%] and hardly changes.

In the range where the expansion ratio (h/d) is 29.8 or more, the oil carryover rate (E) increases as the expansion ratio (h/d) increases. For example, when the expansion ratio (h/d) is about 29.8, the oil carryover rate (E) is about 1.5 [%]. When the expansion ratio (h/d) is 31, the oil carryover rate (E) is about 2 [%]. When the expansion ratio (h/d) is 32, the oil carryover rate (E) is about 4 [%].

FIG. 7 shows that the oil carryover rate (E) improves when the expansion ratio (h/d) is 3 or more. 3≤h/d corresponds to d≤h/3. When the expansion ratio (h/d) is 5 or more, the oil carryover rate (E) particularly improves. 5≤h/d corresponds to d≤h/5.

FIG. 7 shows that the oil carryover rate (E) improves when the expansion ratio (h/d) is 31 or less. It is understood that the oil carryover rate (E) particularly improves when the expansion ratio (h/d) is 29.8 or less. h/d≤29.8 approximately corresponds to M/(π×D2)≤d. Specifically, M/(π×D2)=132/(π×76)=0.55285 is met. When M/(π×D2)=d is met, h/d=15.4/0.55285=27.855 is met. The value h/d is approximate to 29.8.

According to the test results shown in FIG. 7, the expansion ratio (h/d) is preferably 3 or more and 31 or less, and more preferably 5 or more and 29.8 or less.

Advantages

According to the compressor (10) of the present embodiment, the discharge gas (G) is discharged from the open ends (75a) of the first gas passages (75) at the upper end (71a) of the rotor (71) of the electric motor (70), and is introduced into the first space (U) surrounded by the upper end (71a) of the rotor (71), the lid member (110), and the tubular member (103). The discharge gas (G) temporarily stays in the first space (U), and is diffused over the entire circumferential direction. The discharge gas (G) is discharged radially outward from the first space (U) toward the space (V) above the stator (72) outside the first space (U) through the gap (120) between the lower end (103a) of the tubular member (103) and the upper end (71a) of the rotor (71).

The discharge gas (G) discharged upward from the first gas passages (75) of the rotor (71) temporarily stays in the first space (U), and is diffused over the entire circumferential direction. This allows the flow velocity of the discharge gas (G) discharged radially outward through the gap (120) toward the space (V) above the stator (72) outside the first space (U) to be almost uniform in the circumferential direction (T).

In the compressor (10) of the present embodiment, the first space (U) is formed above the rotor (71) of the electric motor (70). This can reduce the flow disturbance of the discharge gas (G) in the space (V) above the stator (72) of the electric motor (70), reducing the oil carryover.

Specifically, the flow disturbance of the discharge gas (G) discharged to the space (V) above the stator (72) from the third gas passages (77) between the adjacent coils (73) and the fourth gas passage (78) between the rotor (71) and the stator (72) can be reduced, and thus the oil carryover of the compressor (10) can be reduced.

The flow disturbance of the discharge gas (G) passing through the second gas passages (76) (core cuts (72d)) between the outer periphery (72c) of the stator (72) and the casing (20) can be reduced, and thus the oil carryover of the compressor (10) is reduced.

If the distance (d) between the lower end (103a) of the tubular member (103) and the upper end (71a) of the rotor (71) (the vertical dimension of the gap (120)) is too large, the discharge gas (G) introduced into the first space (U) through the first gas passages (75) in the rotor (71) is excessively discharged outside the first space (U) through the gap (120). The discharge gas (G) is less likely to stay in the first space (U), and is less likely to be diffused in the circumferential direction.

In the compressor (10) of the present embodiment, the distance (d) between the lower end (103a) of the tubular member (103) and the upper end (71a) of the rotor (71) (the vertical dimension of the gap (120)) is set to be equal to or less than a predetermined value (d≤h/3). The discharge gas (G) introduced from the first gas passages (75) of the rotor (71) into the first space (U) is not excessively discharged outside the first space (U) through the gap (120). The discharge gas (G) is more likely to stay in the first space (U), and is more likely to be diffused in the circumferential direction. This is more advantageous in reducing the flow disturbance of the discharge gas (G) in the space (V) above the stator (72).

If the distance (d) between the lower end (103a) of the tubular member (103) and the upper end (71a) of the rotor (71) (the vertical dimension of the gap (120)) is too small, the discharge gas (G) introduced from the first gas passages (75) of the rotor (71) into the first space (U) is less likely to be discharged outside the first space (U) through the gap (120). At this time, the flow of the discharge gas (G) passing through the first gas passages (75) in the rotor (71) is hindered, so that the amount of the discharge gas (G) from which some of the mist-like lubricant (L) is separated while passing through the space below the electric motor (70) decreases, and the oil carryover rate (E) increases.

In the compressor (10) of the present embodiment, the distance (d) between the lower end (103a) of the tubular member (103) and the upper end (71a) of the rotor (71) (the vertical dimension of the gap (120)) is set to be equal to or larger than a predetermined value (M/(π×D2)≤d). This reduces hindrance of the discharge gas (G) passing through the first gas passages (75) in the rotor (71). This is more advantageous in reducing the flow disturbance of the discharge gas (G) in the space (V) above the stator (72).

The cover (100) can suppress agitation of the discharge gas (G) caused by the rotation of the balance weight (60). The number of components can be reduced by forming the tubular member (103) as part of the cover (100).

Fixing the lid member (110) to the lower surface (60d) of the balance weight (60) allows easy disposition of the lid member (110) below the balance weight (60) and above the rotor (71).

The outer diameter (D1) of the tubular member (103) is equal to or smaller than the outer diameter (D3) of the rotor (71). This is more advantageous in preventing the discharge gas (G) flowing radially outside the rotor (71) (e.g., the discharge gas (G) that flows out of the third gas passages (77) and the fourth gas passage (78) to the space (V) above the stator (72)) from entering the first space (U).

Second Embodiment

A compressor (10) according to a second embodiment will be described. FIG. 8 is equivalent to FIG. 5 and illustrates the second embodiment.

In the present embodiment, the tubular member (103) is not integral with the outer peripheral cover portion (102) of the cover (100), but is separate from the outer peripheral cover portion (102) of the cover (100). The outer peripheral cover portion (102) of the cover (100) extends only to the lower end (60c) of the balance weight (60).

The lid member (110) and the tubular member (103) are integral with each other. The upper end of the tubular member (103) is fixed to the outer periphery (110a) of the lid member (110). The tubular member (103) extends downward from the outer periphery (110a) of the lid member (110).

OTHER EMBODIMENTS

The tubular member (103) may extend downward from a position radially inside the outer periphery (110a) of the lid member (110).

The compressor (10) does not need to be applied to the refrigeration apparatus (1), and may be used for compressing a fluid other than a refrigerant, such as air.

While the embodiments have been described above, it will be understood that various changes in form and details can be made 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.