Compressor

Abstract

This compressor comprises: a shell that constitutes an outer shell; a compression mechanism unit that is accommodated in the shell and that constitutes a compression chamber for compressing a refrigerant; a drive mechanism unit that is accommodated in the shell and that generates rotational motion; a shaft that connects the drive mechanism unit and the compression mechanism unit and transmits the rotational motion of the drive mechanism unit to the compression mechanism unit, the shaft having a main shaft part and an eccentric shaft part that is provided to an end portion on the side near the compression mechanism unit and is eccentric with respect to the main shaft part; and a cylindrical slider that is attached to the eccentric shaft part. The compression mechanism unit has: a fixed scroll; and a swing scroll in which there is formed a cylindrical boss disposed so that the slider slides in the interior thereof, and which is operated by the shaft and undergoes a swing motion with respect to the fixed scroll. The boss has a constant inside diameter in a boss axial direction that follows the central axis of the boss, the boss being formed so that the wall thickness at an opening end part is greater than the wall thickness in a boss-axial-direction central part.

Description

Compressor

[0001] The present disclosure relates to a compressor that compresses a refrigerant.

[0002] In recent years, construction of large factories and server rooms has been increasing, particularly in Asia. This has led to a growing need for larger-capacity compressors, creating a demand for compressors with increased displacement. Increasing the displacement also increases the load on the rocking bearing. If a compressor with a current rocking bearing structure is used with an increased displacement, the sliding parts around the drive shaft may be damaged due to insufficient strength, resulting in reduced reliability. To address this issue, some compressors employ surface treatments or high-strength materials for the sliding parts around the drive shaft to improve the strength of the sliding parts around the drive shaft (see, for example, Patent Document 1). In the compressor disclosed in Patent Document 1, a hard coating, such as a diamond-like carbon (DLC) coating, is formed on the outer circumferential surface of a bushing (slider) attached to the outer periphery of the eccentric shaft.

[0003] International Publication No. 2019 / 229842

[0004] However, applying a surface treatment to the outer surface of the bushing or using a high-strength material, as in Patent Document 1, significantly increases costs due to the materials and equipment required. Furthermore, if, instead of providing a hard coating on the bushing to strengthen the sliding portion around the drive shaft, the outer diameter of the boss housing the eccentric shaft and the bushing is increased to increase the wall thickness, the boss's rigidity becomes too high relative to the bushing, making it difficult for the boss to deform in response to deformation or tilt of the bushing during compressor operation. This reduces the contact area between the outer surface of the bushing and the inner surface of the boss, resulting in increased wear at the contact points. On the other hand, if the bushing is not strengthened as in Patent Document 1 and the boss is not strengthened by increasing its diameter in order to avoid increased costs, the boss will deform in response to deformation or tilt of the bushing, but cracks will form at the open end of the boss. As such, with conventional configurations, it has been difficult to improve the reliability of the boss, which is a bearing structure, while suppressing increases in cost in response to increased capacity.

[0005] The present disclosure is intended to solve the above-mentioned problems, and provides a compressor that can improve the reliability of the boss while suppressing an increase in cost as the capacity increases.

[0006] The compressor according to the present disclosure comprises a shell forming an outer casing, a compression mechanism unit housed in the shell and forming a compression chamber for compressing a refrigerant, a drive mechanism unit housed in the shell and generating rotational motion, and a shaft connecting the drive mechanism unit and the compression mechanism unit and transmitting the rotational motion of the drive mechanism unit to the compression mechanism unit, the shaft having a main shaft portion and an eccentric shaft portion provided at an end of the compression mechanism unit that is eccentric with respect to the main shaft portion, and a cylindrical slider attached to the eccentric shaft portion, the compression mechanism unit having a fixed scroll and an oscillating scroll that is driven by the shaft and oscillates relative to the fixed scroll, the boss having a constant inner diameter in the boss axial direction, which is a direction along its central axis, and is formed so that the wall thickness at the open end is thicker than the wall thickness at the center in the boss axial direction.

[0007] In the compressor of the present disclosure, the boss is formed so that the wall thickness at the open end is thicker than the wall thickness at the central portion in the boss axial direction. This allows the central portion of the boss to deform to follow the shape or inclination of the slider, suppressing abnormal wear on the inner circumferential surface of the boss. Furthermore, the wall thickness improves the strength of the open end of the boss, suppressing cracking at the open end of the boss even if the central portion of the boss deforms. Therefore, varying the wall thickness of the boss in the boss axial direction improves the reliability of the boss, eliminating the need to use high-strength materials as in the past to cope with increased bearing loads due to larger capacity. This allows the reliability of the boss to be improved while suppressing increases in cost.

[0008] 10 is a longitudinal sectional view showing a compressor according to a first embodiment. FIG. 11 is a longitudinal sectional view showing the configuration of an orbiting scroll and a frame in the compressor of FIG. 1. FIG. 12 is a longitudinal sectional view showing an eccentric shaft portion and a bearing structure for the eccentric shaft portion in the compressor of FIG. 1. FIG. 13 is a schematic diagram showing a refrigerant circuit including the compressor of FIG. 1. FIG. 14 is a longitudinal sectional view showing the configuration of a boss of FIG. 3. FIG. 15 is a schematic diagram explaining the effect of the boss of FIG. 3. FIG. 16 is a sectional view showing a modified example of the frame among the orbiting scroll and frame of FIG. 2. FIG. 5 is a longitudinal sectional view showing the relationship between the length of the large diameter portion in the boss and the overall length of the boss of FIG. 5. FIG. 8 is a diagram showing the relationship between the length of the large diameter portion in the boss and the maximum stress generated at the open end of the boss. FIG. 17 is a schematic diagram showing a modified example of the eccentric shaft portion in the eccentric shaft portion and bearing structure of FIG. 3. FIG. 18 is a schematic diagram showing a modified example of the boss in the eccentric shaft portion and bearing structure of FIG. 10. FIG. 19 is a longitudinal sectional view showing the configuration of a boss in the orbiting scroll of a compressor according to a second embodiment.

[0009] A compressor 100 according to an embodiment of the present disclosure will be described below with reference to the drawings. In the following drawings, components denoted with the same reference numerals are identical or equivalent and will be common throughout the following embodiments. The configurations of components shown throughout the specification are merely examples and are not intended to be limiting. The size relationships between components in the drawings may differ from those in reality. While directional terms (e.g., "up," "down," "right," "left," "front," "rear," etc.) are used appropriately to facilitate understanding, these terms are used for convenience of explanation only and do not limit the arrangement or orientation of devices or components.

[0010] Embodiment 1. [Configuration of Compressor 100] Figure 1 is a longitudinal cross-sectional view showing a compressor 100 according to Embodiment 1. The compressor 100 is a low-pressure shell compressor in which a shell 2 is filled with a low-pressure refrigerant. The compressor 100 is applied to refrigeration cycle devices used for refrigeration or air conditioning purposes, such as refrigerators, freezers, vending machines, air conditioners, refrigeration systems, and water heaters. The compressor 100 draws in refrigerant circulating through a refrigerant circuit 200 (see Figure 4 described below) of the refrigeration cycle device, compresses it, and discharges it in a high-temperature, high-pressure state.

[0011] Fig. 2 is a vertical cross-sectional view showing the configuration of the orbiting scroll 40 and the frame 6 in the compressor 100 of Fig. 1. In Fig. 2, the direction of the thrust load is indicated by a white arrow. Fig. 3 is a vertical cross-sectional view showing the eccentric shaft portion 7a and the bearing structure of the eccentric shaft portion 7a in the compressor 100 of Fig. 1. The configuration of the compressor 100 will be described with reference to Figs. 1 to 4.

[0012] As shown in Fig. 1, the compressor 100 includes a shell 2, an oil pump 3, a drive mechanism 4, a compression mechanism 5, a frame 6, and a shaft 7. The shaft 7 has a main shaft portion 7c disposed substantially at the center of the shell 2, and an eccentric shaft portion 7a that constitutes the end of the shaft 7 on the compression mechanism 5 side (the upper end of the shaft 7 in Fig. 1) and is eccentric with respect to the main shaft portion 7c. The compressor 100 further includes a suction pipe 11, a discharge pipe 12, and a subframe 20. The compressor 100 uses, as a refrigerant, for example, CO ２ In the compressor 100 of the present disclosure, CO ２ In addition, application to high-pressure refrigerants such as R32 or R410A is particularly desirable.

[0013] (Shell 2) The shell 2 forms the outer shell of the compressor 100. The shell 2 includes a middle shell 2c, an upper shell 2a disposed above the middle shell 2c, and a lower shell 2b disposed below the middle shell 2c, and forms the outer shell of the compressor 100. The shell 2 is cylindrical with a bottom and has an oil reservoir 3a at its bottom. The oil pump 3, drive mechanism 4, compression mechanism 5, frame 6, shaft 7, subframe 20, etc. are housed inside the shell 2. The middle shell 2c forms the cylindrical peripheral wall of the shell 2. The upper end of the middle shell 2c is closed by the dome-shaped upper shell 2a. The lower end of the middle shell 2c is closed by the lower shell 2b. A discharge chamber 13 is formed between the upper shell 2a of the shell 2 and the compression mechanism 5, and the discharge chamber 13 is a high-pressure space. The discharge chamber 13 is provided above the compression mechanism 5 and contains the refrigerant compressed and discharged by the compression mechanism 5. The compressor 100 of the present disclosure has a low-pressure shell structure, i.e., a space in which the drive mechanism 4, which is an electric motor, is disposed, is filled with refrigerant taken in from the suction pipe 11 before being compressed.

[0014] (Oil Pump 3) The oil pump 3 is disposed at the bottom of the shell 2. The oil pump 3 is housed in the shell 2 and draws oil from an oil reservoir 3a. The oil pump 3 then supplies the oil drawn from the oil reservoir 3a to lubricated parts, such as the bearing structure of the compressor 100, to lubricate the lubricated parts. The oil used in the compressor 100 is, for example, polyol ester (POE) oil. In recent years, the capacity of refrigeration cycle devices has increased, and the amount of refrigerant sealed in the refrigerant circuit 200 (see FIG. 4 , described below) has also increased. Furthermore, as the capacity increases, the piping length increases, which impairs the return of oil to the compressor 100. Therefore, it is desirable to use polyol ester (POE) oil, which is compatible with the refrigerant, as the oil used in the compressor 100. When polyol ester (POE) oil is used in a low-pressure shell, the viscosity grade (VG) of the oil is desirably 32 or greater and less than 68 to prevent an increase in oil viscosity and deterioration of sliding loss.

[0015] (Drive Mechanism 4) The drive mechanism 4 is installed inside the shell 2, between the frame 6 and the subframe 20, and generates rotational motion to rotate the shaft 7. The drive mechanism 4 includes a stator 4b fixed to the inner circumferential wall of the middle shell 2c and a rotor 4a disposed on the inner circumferential side of the stator 4b. The stator 4b rotates the rotor 4a using power supplied from outside the compressor 100. The stator 4b is configured, for example, by mounting a multi-phase winding on a laminated core. A shaft 7 is fixed to the rotor 4a, transmitting the rotational driving force of the drive mechanism 4 to the orbiting scroll 40. When power is supplied to the stator 4b, the rotor 4a rotates on its own axis, thereby rotating integrally with the shaft 7. The drive mechanism 4 can change the rotation speed of the shaft 7, for example, by inverter control. The compressor 100 is, for example, a compressor with a maximum operating rotation speed of 100 rps or more.

[0016] (Compression Mechanism 5) The compression mechanism 5 is housed in the shell 2 and compresses a fluid such as a refrigerant drawn into the shell 2 from the suction pipe 11. The compression mechanism 5 includes a fixed scroll 30 fixed to the shell 2 and an orbiting scroll 40 that orbits (i.e., revolves) relative to the fixed scroll 30. The compression mechanism 5 defines a compression chamber 5a that compresses the refrigerant by combining the fixed scroll 30 and the orbiting scroll 40. The fixed scroll 30 is fixed to the shell 2, for example, by being fixed to the upper end of the frame 6 with a fastener such as a bolt so as to close the cylindrical opening of the frame 6. In this case, the fixed scroll 30 is indirectly fixed to the shell 2 via the frame 6. Note that although the example in which the fixed scroll 30 is fixed to the frame 6 has been described, the fixed scroll 30 may also be directly fixed to the middle shell 2c of the shell 2 without being fixed to the frame 6.

[0017] The fixed scroll 30 compresses a fluid such as a refrigerant together with the orbiting scroll 40. The fixed scroll 30 forms a compression chamber 5a between the orbiting scroll 40 and the fixed scroll 30. The fixed scroll 30 is disposed opposite the orbiting scroll 40. The fixed scroll 30 has a base plate 30a and a spiral portion 31 extending downward from the lower surface of the base plate 30a. The spiral portion 31 protrudes toward the orbiting scroll 40 from the wall surface of the base plate 30a facing the orbiting scroll 40, and has a spiral-shaped protrusion in cross section parallel to the base plate 30a. The base plate 30a, together with the spiral portion 31 of the fixed scroll 30 and the spiral portion 41 of the orbiting scroll 40, constitutes the compression chamber 5a. The base plate 30a is fixed within the shell 2 so that its outer circumferential surface faces the inner circumferential surface of the middle shell 2c and the outer circumferential edge side of the lower end surface of the base plate 30a faces the upper part of the frame 6. Furthermore, a discharge port 32 for discharging the refrigerant compressed in the compression chamber 5a is formed through the base plate 30a in the center of the base plate 30a that constitutes the fixed scroll 30. A reed valve 51 and a valve guard 53 are attached to the fixed scroll 30. The reed valve 51 is disposed on the discharge chamber 13 side of the compression mechanism 5, and opens and closes the discharge port 32 in accordance with the discharge pressure of the refrigerant. The valve guard 53 supports the reed valve 51 from the back when the reed valve 51 is open, and protects the reed valve 51 from excessive deformation.

[0018] The orbiting scroll 40 compresses a fluid such as a refrigerant together with the fixed scroll 30. The orbiting scroll 40 forms a compression chamber 5a between the fixed scroll 30 and the orbiting scroll 40. The orbiting scroll 40 is disposed opposite the fixed scroll 30. The orbiting scroll 40 is attached to the shaft 7 eccentrically with respect to the central axis of the shaft 7 (particularly, the central axis As1 of the main shaft portion 7c). Therefore, the orbiting scroll 40 is eccentric with respect to the fixed scroll 30. The orbiting scroll 40 has a base plate 40a and a spiral portion 41 extending upward from the upper surface of the base plate 40a. The spiral portion 41 protrudes toward the fixed scroll 30 from the wall surface of the base plate 40a facing the fixed scroll 30, and has a spiral-shaped protrusion in cross section parallel to the base plate 40a. The base plate 40a is a disc-shaped member, and together with the spiral portion 41 of the orbiting scroll 40 and the spiral portion 31 of the fixed scroll 30, they form the compression chamber 5a.

[0019] A hollow cylindrical boss 40c is formed in the center of the base plate 40a of the orbiting scroll 40 on the surface opposite to the surface on which the spiral portion 41 is formed (the lower surface of the base plate 40a in FIG. 1). An eccentric shaft portion 7a at the upper end of the shaft 7 is inserted into the boss 40c. A cylindrical slider 16 (described later) is attached to the eccentric shaft portion 7a. By inserting the eccentric shaft portion 7a of the shaft 7 into the boss 40c, the boss 40c of the orbiting scroll 40 and the shaft 7 are engaged via the slider 16. In the example of FIG. 3, an oscillating bearing portion 40e made of a copper alloy, such as a bronze-based metal (e.g., a copper-lead alloy), is provided on the inner circumferential surface of the boss 40c on which the slider 16 slides. The oscillating bearing portion 40e is provided in the boss 40c by press-fitting a bearing material used for sliding bearings, such as a copper alloy, and is fixed to the boss 40c by a fixture 8 (see FIG. 2). The rocking bearing 40e may be omitted. The slider 16 slides against the rocking bearing 40e (or the inner peripheral surface of the boss 40c in a configuration without the rocking bearing 40e) via an oil film. The slider 16 is made of, for example, a sintered metal. The rocking bearing 40e may be made of a composite metal containing a resin material such as polytetrafluoroethylene resin (hereinafter abbreviated as PTFE). The detailed configuration of the slider 16 will be described later.

[0020] The orbiting scroll 40 has a base plate 40a whose lower surface (i.e., thrust surface 40b supporting a thrust load) opposite to the upper surface on which the spiral portion 41 is formed, supported by a frame 6 fixed within the shell 2. That is, the orbiting scroll 40 supports an axial thrust load by the frame 6. The orbiting scroll 40 oscillates on a thrust bearing 6s of the frame 6 as the shaft 7 rotates. Radial oil supply grooves (not shown) are provided on the lower surface (thrust surface 40b) of the base plate 40a so that lubricating oil is supplied to the thrust surface 40b. The orbiting scroll 40 is restricted in its rotational motion by an Oldham ring 15 and performs an orbital motion, or in other words, an orbital motion, relative to the fixed scroll 30. As shown in FIG. 2 , a pair of base plate Oldham grooves 40br are formed on both sides of a boss 40c on the lower surface of the base plate 40a of the orbiting scroll 40. A pair of claws 15b (see FIG. 1) of the Oldham ring 15, which will be described later, are disposed in the pair of base plate Oldham grooves 40br.

[0021] As shown in FIG. 1 , the Oldham ring 15 is disposed on the lower surface of the base plate 40 a of the orbiting scroll 40, opposite the upper surface on which the spiral portion 41 is formed. The Oldham ring 15 has an annular ring portion (not shown) on which a pair of claws 15 b protruding upward and a pair of claws (not shown) protruding downward are formed. These two pairs of claws are positioned perpendicular to each other. The ring portion (not shown) of the Oldham ring 15 is accommodated in a circular Oldham receiving portion 6 f (see FIG. 2 ), which will be described later, formed in the thrust bearing 6 s of the frame 6. A pair of frame Oldham grooves (not shown) are formed in the bottom of the Oldham receiving portion 6 f at positions perpendicular to the pair of base plate Oldham grooves 40 br (see FIG. 2 ) when the orbiting scroll 40 is disposed on the frame 6. A pair of claws 15b at the top of the Oldham ring 15 is disposed in a pair of base plate Oldham grooves 40br of the orbiting scroll 40, and although not shown, a pair of claws at the bottom of the Oldham ring 15 is disposed in a pair of frame Oldham grooves of the frame 6. The Oldham ring 15 prevents the orbiting scroll 40 from rotating on its axis and allows the orbiting scroll 40 to orbit.

[0022] The fixed scroll 30 and the orbiting scroll 40 have their spiral portions 31 and 41 facing each other on their opposing surfaces, and the spiral portions 31 and 41 mesh with each other. A compression chamber 5a is formed in the space where the spiral portion 31 of the fixed scroll 30 and the spiral portion 41 of the orbiting scroll 40 mesh with each other. When the orbiting scroll 40 is caused to oscillate by the shaft 7, the gaseous refrigerant is compressed in the compression chamber 5a. Note that seal members 21 are disposed at the tips of the spiral portion 31 of the fixed scroll 30 and the spiral portion 41 of the orbiting scroll 40 to maintain the airtightness of the compression chamber 5a.

[0023] (Frame 6) The frame 6 is formed in a cylindrical shape, its outer periphery is fixed to the shell 2, and its inner periphery houses the compression mechanism 5. The frame 6 supports the orbiting scroll 40 of the compression mechanism 5 so that it can freely orbit. The frame 6 has a thrust bearing 6s that faces the lower surface of the base plate 40a of the orbiting scroll 40, and the thrust load generated during operation of the compressor 100 is supported by the thrust bearing 6s via the thrust surface 40b of the orbiting scroll 40.

[0024] Furthermore, the frame 6 has a support portion 6e on the drive mechanism 4 side (the lower portion of the frame 6 in FIG. 1 ) that supports the shaft 7. The support portion 6e has an axial hole that penetrates in the vertical direction, and the main shaft portion 7c of the shaft 7 is disposed in this hole. A cylindrical sleeve 17, which will be described later, is attached to the main shaft portion 7c. In the example of FIG. 1 , the inner circumferential surface of the support portion 6e is provided with a main bearing portion 6a made of a copper alloy, such as a bronze-based metal (e.g., a copper-lead alloy). The main bearing portion 6a is fixed to the frame 6 by, for example, press-fitting a bearing material used in sliding bearings, such as a copper alloy. Note that the main bearing portion 6a may be omitted. The support portion 6e rotatably supports the main shaft portion 7c of the shaft 7 via the main bearing portion 6a and a sleeve 17. The sleeve 17 slides against the main bearing portion 6a via an oil film. The sleeve 17 interposed between the main bearing portion 6a and the main shaft portion 7c absorbs the tilt between the frame 6 and the shaft 7. The detailed configuration of the sleeve 17 will be described later.

[0025] 2, a boss housing portion 6d for housing the boss 40c of the orbiting scroll 40 is provided between the thrust bearing 6s and the support portion 6e in the center of the frame 6. The space inside the boss housing portion 6d is a space in which the boss 40c operates when the shaft 7 is rotating, i.e., when the compressor 100 is operating, and is generally cylindrical. During operation of the compressor 100, the boss 40c of the orbiting scroll 40 performs an orbiting motion within the boss housing portion 6d of the frame 6. Hereinafter, the range in which the boss 40c operates during operation of the compressor 100 may be referred to as a boss operating region.

[0026] (Shaft 7) As shown in Fig. 1 , the shaft 7 connects the drive mechanism 4 and the orbiting scroll 40 and transmits the rotational motion of the drive mechanism 4 to the orbiting scroll 40 of the compression mechanism 5. A main shaft 7c of the shaft 7, which is located above the rotor 4a of the drive mechanism 4, is rotatably supported by a main bearing 6a provided on the frame 6. A sub-shaft 7d of the shaft 7, which is located below the rotor 4a of the drive mechanism 4, is rotatably supported by a sub-bearing 20a of the sub-frame 20. An oil pump 3 that sucks up oil accumulated in an oil sump 3a is disposed at the lower end of the shaft 7. An oil circuit 7b is formed inside the shaft 7 to circulate the oil sucked up by the oil pump 3 upward.

[0027] A slider 16 is attached to the outer peripheral surface of the eccentric shaft portion 7a that constitutes the upper end of the shaft 7. The slider 16 is disposed within a boss 40c formed at the bottom of the orbiting scroll 40. The orbiting scroll 40 is attached to the shaft 7 via this slider 16. As a result, the orbiting scroll 40 rotates as the shaft 7 rotates.

[0028] As shown in FIG. 3 , the shaft 7 has a crowning structure to prevent uneven oil film formation due to axial deflection of the shaft 7. The crowning structure is provided on a portion of the shaft 7 in the extension direction, and is formed by machining the cylindrical outer peripheral surface of the shaft 7 so that the middle portion is convex, for example, in a mountain shape. In FIG. 3 , an arc-shaped swing shaft crowning portion 7f that is convex outward is formed on the outer peripheral wall of the eccentric shaft portion 7a that abuts against the inner peripheral surface of the slider 16. Furthermore, an arc-shaped spindle crowning portion 7g that is convex outward is formed on the outer peripheral wall of the main shaft portion 7c that abuts against the inner peripheral surface of the sleeve 17. The arc-shaped swing shaft crowning portion 7f that is convex outward contacts the inner peripheral surface of the slider 16, thereby suppressing tilt of the slider 16 relative to the swing bearing portion 40e (or the inner peripheral surface of the boss 40c if the swing bearing portion 40e is not provided). Furthermore, the outwardly convex, arc-shaped spindle-side crowning portion 7g comes into contact with the inner peripheral surface of the sleeve 17, thereby suppressing tilt of the sleeve 17 relative to the main bearing portion 6a (or the inner peripheral surface of the support portion 6e if the main bearing portion 6a is not provided). Note that these crowning structures may be omitted, or alternatively, only one of the swing-shaft-side crowning portion 7f and the spindle-side crowning portion 7g may be provided.

[0029] (Slider 16) As shown in FIG. 3, the slider 16 is a cylindrical member formed into a hollow portion 16c into which the eccentric shaft portion 7a of the shaft 7 is inserted. The slider 16 is rotatably housed in the boss 40c of the orbiting scroll 40. The slider 16 is interposed between the inner circumferential surface 40ci of the boss 40c and the eccentric shaft portion 7a, allowing the orbiting radius of the orbiting scroll 40 to be variable. The slider 16 rotates together with the shaft 7 and is arranged to slide relative to the orbiting bearing portion 40e. Although not shown, the hollow portion 16c of the slider 16 and the eccentric shaft portion 7a of the shaft 7 are formed so that the eccentric shaft portion 7a fits into the hollow portion 16c and the slider 16 slides only in a fixed direction on a plane perpendicular to the axial direction of the shaft 7. The slider 16 rotates together with the rotating shaft 7. The slider 16 and the shaft 7 may be configured to rotate together by engagement of a detent pin with a detent groove, engagement of a key with a key groove, press fitting, shrink fitting, or the like.

[0030] (Sleeve 17) The sleeve 17 is a cylindrical member formed into a hollow portion 17c into which the main shaft portion 7c of the shaft 7 is inserted. The main shaft portion 7c of the shaft 7, which is located above the drive mechanism 4, is inserted into the hollow portion 17c of the sleeve 17. The sleeve 17 is disposed between the main bearing portion 6a and the main shaft portion 7c of the shaft 7. The sleeve 17 rotates together with the shaft 7 and is disposed so as to slide relative to the main bearing portion 6a. A detent portion 17b (see FIG. 1) is formed on the inner circumferential wall constituting the hollow portion 17c of the sleeve 17. The detent portion 17b is formed by recessing the inner circumferential wall at the vertical end of the sleeve 17 and forming a groove. The detent portion 17b formed on the inner circumferential wall of the sleeve 17 engages with a detent pin (not shown) formed on the outer circumferential wall of the main shaft portion 7c of the shaft 7, allowing the sleeve 17 to rotate together with the rotating shaft 7. In addition, the sleeve 17 and the shaft 7 may be configured to rotate together not only by engagement between the anti-rotation pin and the anti-rotation portion 17b, but also by engagement between a key and a key groove, press fitting, shrink fitting, etc.

[0031] (Subframe 20) As shown in FIG. 1 , the subframe 20 is disposed below the drive mechanism 4 inside the shell 2 and is fixed to the inner peripheral surface of the middle shell 2c. The subframe 20 rotatably supports the subshaft 7d of the shaft 7 that is below the drive mechanism 4 via a sub-bearing 20a. The shaft 7 slides on the sub-bearing 20a via an oil film. In FIG. 1 , the sub-bearing 20a is configured as a ball bearing, but the sub-bearing 20a is not limited to a ball bearing and may be configured as another type of bearing. The sub-bearing 20a is fitted into a sub-bearing housing 23 fixed to the center of the subframe 20.

[0032] (Suction Pipe 11) The suction pipe 11 is a pipe that draws the gaseous refrigerant into the shell 2. The suction pipe 11 is disposed on the side wall of the shell 2 and is connected to the middle shell 2c.

[0033] (Discharge pipe 12) The discharge pipe 12 is a pipe that discharges the refrigerant compressed by the compression mechanism 5 to the outside of the shell 2. The discharge pipe 12 is arranged at the top of the shell 2 and connected to the upper shell 2a. The discharge pipe 12 connects a discharge chamber 13 in the shell 2 to a refrigerant circuit 200 (for example, a condenser 201 shown in FIG. 4 , which will be described later) outside the shell 2.

[0034] [Explanation of Operation of Compressor 100] Next, the operation of the compressor 100 will be described. When power is supplied to the stator 4b from outside the compressor 100, a magnetic field is generated in the stator 4b. This magnetic field acts to rotate the rotor 4a. That is, when power is supplied to the stator 4b, the rotor 4a generates torque, causing the shaft 7, which is supported by the support portion 6e of the frame 6 and the auxiliary bearing 20a of the sub-frame 20, to rotate. The orbiting scroll 40 connected to the shaft 7 is oscillated while its rotation is restricted by the Oldham ring 15, which reciprocates within the frame Oldham groove (not shown) of the frame 6. Through these operations, the compressor 100 changes the volume of the compression chamber 5a formed by the combination of the spiral portion 31 of the fixed scroll 30 and the spiral portion 41 of the orbiting scroll 40.

[0035] As the orbiting scroll 40 swings, gaseous refrigerant is drawn into the shell 2 through the suction pipe 11 and is drawn into the compression chamber 5a formed between the scroll portion 31 of the fixed scroll 30 and the scroll portion 41 of the orbiting scroll 40. The compressed refrigerant is then discharged from the discharge port 32 formed in the base plate 30a of the fixed scroll 30 by opening the reed valve 51 and is then discharged through the discharge pipe 12 to a refrigerant circuit 200 (e.g., a condenser 201 shown in FIG. 4 ) outside the compressor 100. In addition, in the compressor 100, lubricating oil stored in the lower part of the shell 2 is supplied from an oil circuit 7b provided in the shaft 7 to each sliding part, such as the support portion 6e, the auxiliary bearing 20a, and the thrust surface 40b. The oil flowing to the thrust surface 40b is first pumped up by the oil pump 3 to lubricate the bearing structure of the eccentric shaft portion 7a. After lubricating the bearing structure of the eccentric shaft portion 7 a, the oil is stored in the boss accommodating portion 6 d of the frame 6, and then flows through radial oil supply grooves (not shown) provided in the thrust surface 40 b to the base plate Oldham groove 40 br, and lubricates the Oldham ring 15.

[0036] Fig. 4 is a schematic diagram showing a refrigerant circuit 200 including the compressor 100 of Fig. 1. The refrigerant circuit 200 includes the compressor 100, a condenser 201, an expansion device 202, an evaporator 203, and an accumulator 204. As shown in Fig. 4, the refrigerant circuit 200 is configured by connecting the compressor 100, the condenser 201, the expansion device 202, the evaporator 203, and the accumulator 204 in series with refrigerant piping.

[0037] The compressor 100 is the compressor 100 of the first embodiment, and compresses the low-pressure gas-phase refrigerant taken in, changing it into a high-temperature, high-pressure gas-phase refrigerant. The condenser 201 dissipates heat from the high-temperature, high-pressure gas-phase refrigerant sent from the compressor 100, changing the gas-phase refrigerant into a high-pressure liquid-phase refrigerant. The expansion device 202 reduces the pressure of the high-pressure liquid-phase refrigerant sent from the condenser 201, changing it into a low-temperature, low-pressure liquid-phase refrigerant. The expansion device 202 is, for example, an expansion valve. The evaporator 203 vaporizes the liquid-phase refrigerant sent from the expansion device 202, changing it into a low-pressure gas-phase refrigerant. At this time, the refrigerant undergoes a phase change, thereby cooling the area around the evaporator 203. The gas-phase refrigerant that has absorbed the heat of vaporization is taken back into the compressor 100. In this way, in the refrigerant circuit 200, the refrigerant, which serves as a working fluid, circulates while undergoing phase changes between a gas-phase refrigerant and a liquid-phase refrigerant. In the refrigerant circuit 200, heat is released from the refrigerant during the phase change from gas phase refrigerant to liquid phase refrigerant, and heat is absorbed by the refrigerant during the phase change from liquid phase refrigerant to gas phase refrigerant. In the refrigerant circuit 200, heating or cooling is performed by utilizing this heat release or absorption.

[0038] The configuration of the refrigerant circuit 200 to which the compressor 100 is applied is not limited to the above configuration. For example, the refrigerant circuit 200 may be configured to switch between heating operation and cooling operation. In this case, the refrigerant circuit 200 includes a flow path switching device that switches the flow path through which the refrigerant flows between the cooling operation and the heating operation. The flow path switching device is configured, for example, with a four-way valve.

[0039] Fig. 5 is a vertical cross-sectional view showing the configuration of the boss 40c in Fig. 3. Fig. 6 is a schematic diagram illustrating the effect of the boss 40c in Fig. 3. The configuration of the boss 40c, and the movement and deformation of the boss 40c during operation of the compressor 100 will be described in detail with reference to Figs. 5 and 6.

[0040] 5, the boss 40c is formed such that the wall thickness To at the open end Bo is greater than the wall thickness Tm at the central portion Bm in the boss axial direction, which is the direction along the central axis Ab. The boss 40c has a substantially constant inner diameter in the boss axial direction, and an annular step 40cc formed on the outer peripheral surface 40co causes the outer diameter and wall thickness to change in the boss axial direction. The portion of the boss 40c closer to the open end Bo than the step 40cc has an outer diameter (second outer diameter D2) that is larger than the outer diameter (first outer diameter D1) of the central portion Bm.

[0041] The boss 40c is composed of three portions, sequentially arranged from the thrust surface 40b in the boss axial direction, i.e., from the base end toward the open end of the boss 40c: a small diameter portion B1, a connecting portion B3, and a large diameter portion B2. The large diameter portion B2 includes the open end Bo of the boss 40c and constitutes the side of the open end Bo relative to the step 40cc. The small diameter portion B1 includes the central portion Bm of the boss 40c and constitutes the side of the base end Br relative to the step 40cc. The connecting portion B3 is the portion of the boss 40c where the step 40cc is formed on the outer circumferential surface 40co, and connects the large diameter portion B2 and the small diameter portion B1.

[0042] In Fig. 5, the step portion 40cc is tapered, and the outer diameter of the connection portion B3 gradually increases from the small diameter portion B1 side toward the large diameter portion B2 side. Also, in Fig. 5, the small diameter portion B1 has a constant outer diameter (first outer diameter D1), and the large diameter portion B2 has a constant outer diameter (second outer diameter D2). When the outer peripheral surface 40co of the boss 40c is inclined at the connection portion B3 as shown in Fig. 5, it is desirable that the angle of the inclination with respect to the inner peripheral surface 40ci be a gentle inclination of 45° or less, i.e., that the rate of change in the outer diameter at the connection portion B3 be small.

[0043] The outer peripheral surface 40co of the boss 40c may be perpendicular at the boundary between the connecting portion B3 and the small diameter portion B1 and at the boundary between the connecting portion B3 and the large diameter portion B2. The outer diameters of the small diameter portion B1 and the large diameter portion B2 do not have to be constant. For example, the outer peripheral surface 40co at the small diameter portion B1 and the large diameter portion B2 may be inclined with respect to the inner peripheral surface 40ci.

[0044] As described above, the boss 40c has a large-diameter portion B2 and a small-diameter portion B1 with different wall thicknesses. The small-diameter portion B1, including the central portion Bm, has lower rigidity than the large-diameter portion B2, including the open end Bo, and is therefore easily deformed to conform to the shape of the slider 16 and other components rotating within the boss 40c. As shown in FIG. 6 , the cylindrical slider 16 deforms so that the portion facing the oscillating-shaft-side crowning portion 7f of the eccentric shaft portion 7a protrudes outward. Therefore, during operation of the compressor 100, the load on the boss 40c is particularly large at the central portion Bm facing the oscillating-shaft-side crowning portion 7f. Because the central portion Bm of the boss 40c has lower rigidity than the large-diameter portion B2 near the open end Bo, it deforms under the load from the slider 16, thereby suppressing wear on the inner circumferential surface 40ci of the boss 40c. Furthermore, since the slider 16 deforms in accordance with the swing shaft-side crowning portion 7f, the effect of the swing shaft-side crowning portion 7f in uniformly forming an oil film is also remarkable. Meanwhile, the large diameter portion B2 including the opening end Bo of the boss 40c has greater rigidity than the small diameter portion B1 including the central portion Bm, making it less likely that cracks will occur at the opening end Bo of the boss 40c. Thus, in the present disclosure, by making the boss 40c of the swing scroll 40 have different diameters, abnormal wear can be suppressed and cracks at the opening end Bo can also be suppressed, making it possible to improve bearing strength while reducing costs compared to conventional methods for increasing capacity or operating at higher speeds.

[0045] As shown in FIG. 5 , the second outer diameter D2 of the large-diameter portion B2 is larger than the first outer diameter D1 of the small-diameter portion B1 to prevent cracking of the open end Bo of the boss 40c. However, as the wall thickness To of the large-diameter portion B2 of the boss 40c increases, the boss operating area (the space within the boss housing portion 6d in FIG. 2) provided in the frame 6 must also be increased. Increasing the space within the boss housing portion 6d, which is the boss operating area, to match the open end Bo where the outer peripheral surface 40co of the boss 40c protrudes most would reduce the area of ​​the thrust surface 40b that receives the thrust load of the spiral portion 41 (see FIG. 2) and would also reduce the range of motion of the Oldham ring 15 (see FIG. 1) that prevents rotation of the spiral portion 41 (see FIG. 2). Therefore, it is preferable that the increase in thickness from the small-diameter portion B1 to the large-diameter portion B2 be equal to or less than half the wall thickness of the small-diameter portion B1, for example, so that D2 - D1 ≦ (D1 - inner diameter of the boss) / 2. Furthermore, according to trial calculations, when the second outer diameter D2 of the large diameter portion B2 is increased and the second outer diameter D2 approaches 1.2 times the first outer diameter D1 of the small diameter portion B1, the change in generated stress becomes extremely small and there is no room for improvement. Therefore, in order to suppress cracking of the open end Bo of the boss 40c and to ensure the area of ​​the thrust surface 40b, etc., it is preferable that the second outer diameter D2 of the large diameter portion B2 of the boss 40c be larger than the first outer diameter D1 of the small diameter portion B1 but not more than 1.2 times the first outer diameter D1.

[0046] (Modification of Frame 6) Figure 7 is a cross-sectional view showing a modification of the frame 6 of the orbiting scroll 40 and frame 6 of Figure 2. In the modified frame 306, the frame inner surface 306di of the boss accommodating portion 306d is shaped to follow the outer peripheral surface 40co of the boss 40c. That is, the boss accommodating portion 306d is provided with a recess 306dr that accommodates the outer peripheral portion of the large diameter portion B2 of the boss 40c when the boss 40c oscillates within the boss accommodating portion 306d. Note that the operating range of the orbiting scroll 40 is restricted by contact between the side surfaces of the spiral portions 31, 41 of the fixed scroll 30 and the orbiting scroll 40, which also restricts the boss operating range within the boss accommodating portion 306d. Therefore, the outer peripheral surface of the small diameter portion B1 of the boss 40c does not contact the frame inner surface 306di and the inner surface of the recess 306dr of the boss accommodating portion 306d.

[0047] In this way, by shaping the frame inner surface 306di of the boss accommodating portion 306d to conform to the outer peripheral surface 40co of the boss 40c, it is possible to provide a large diameter portion B2 on the open end Bo side of the boss 40c while maintaining the area of ​​the thrust surface 40b as before. This makes it possible to improve the reliability of the rocking bearing structure without reducing the strength against thrust loads.

[0048] Figure 8 is a vertical cross-sectional view showing the relationship between the length H2 of the large diameter portion B2 of the boss 40c in Figure 5 and the overall length H of the boss 40c. Figure 9 is a diagram showing the relationship between the length of the large diameter portion B2 of the boss 40c in Figure 8 and the maximum stress generated at the open end Bo of the boss 40c. A preferred range for the length H2 of the large diameter portion B2 relative to the overall length H of the boss 40c in the boss axial direction (the vertical direction in Figure 10) will be described with reference to Figures 8 and 9. The length H1 in Figure 8 is the length from the base end of the boss 40c to the large diameter portion B2 in the boss axial direction, i.e., the length of the small diameter portion B1 and the connecting portion B3 in the boss axial direction.

[0049] The horizontal axis of Fig. 9 represents the length H2 of the large diameter portion B2 of the boss 40c in the boss axial direction, and the vertical axis of Fig. 9 represents the maximum stress F generated at the open end Bo of the boss 40c. As shown in Fig. 8, the overall length H of the boss 40c is the length from the thrust surface 40b to the open end.

[0050] As shown in Figure 9, the longer the length H2 of the large diameter portion B2, the more reliable the cracking resistance of the opening end Bo of the boss 40c is, relative to the stress generated at the opening end Bo. However, if the length H2 of the large diameter portion B2 of the boss 40c is made greater than 0.4 times the total length H, the change in generated stress becomes extremely small, and there is no room for improvement in reliability. A shorter length H2 of the large diameter portion B2 can reduce the amount of material used in the boss 40c. To prevent cracking at the opening end Bo of the boss 40c and reduce material, the length H2 of the large diameter portion B2 of the boss 40c is preferably in the range of 0.1 to 0.4 times the total length H of the boss 40c.

[0051] Furthermore, the length H2 of the large diameter portion B2 of the boss 40c may be determined based on the positional relationship with the oscillation shaft side crowning portion 7f when the eccentric shaft portion 7a is housed in the boss 40c. In Fig. 6, the eccentric shaft portion 7a is housed in the boss 40c so that the oscillation shaft side crowning portion 7f faces the center portion Bm of the boss 40c. In this case, it is preferable that the entire area of ​​the boss 40c that faces the arc-shaped oscillation shaft side crowning portion 7f is the small diameter portion B1.

[0052] Therefore, in a configuration having a oscillating-shaft-side crowning portion 7f as shown in Fig. 6, it is preferable that the large-diameter portion B2 be located below the oscillating-shaft-side crowning portion 7f. More specifically, the large-diameter portion B2 of the boss 40c has its lower end at the open end of the boss 40c in the boss axial direction and its upper end at a position not exceeding the height position of the lower end of the oscillating-shaft-side crowning portion 7f. In other words, the length H2 (see Fig. 8) of the large-diameter portion B2 of the boss 40c in the boss axial direction is set to be equal to or less than the length Hc from the open end of the boss 40c to the lower end of the oscillating-shaft-side crowning portion 7f in the boss axial direction when the eccentric shaft portion 7a is accommodated in the boss 40c.

[0053] Similarly, it is more desirable that the connection portion B3 connecting the large diameter portion B2 and the small diameter portion B1 be located below the oscillating shaft side crowning portion 7f in the boss axial direction, i.e., so that the upper end of the connection portion B3 does not overlap the bulge of the oscillating shaft side crowning portion 7f.

[0054] The configuration of the compressor 100 is not limited to the above configuration. For example, the eccentric shaft portion 7a or the boss 40c may be configured as in the following two modified examples.

[0055] Figure 10 is a schematic diagram showing a modified example of the eccentric shaft portion 7a of the eccentric shaft portion 7a and bearing structure of Figure 3. The eccentric shaft portion 307a of Figure 10 does not have the oscillation shaft-side crowning portion 7f that is provided on the eccentric shaft portion 7a of Figures 3 and 6, and the eccentric shaft portion 307a has a constant outer diameter in the oscillation axis direction, which is the direction along its central axis As2. In this way, even when an eccentric shaft portion 307a without a crowning structure is used, the boss 40c of the present disclosure can suppress abnormal wear of the boss 40c and cracks in the open end Bo. Below, the issues associated with using an eccentric shaft portion 307a without a crowning structure and the effects of the boss 40c will be described in detail.

[0056] During operation of the compressor 100, the eccentric shaft portion 307a deforms within the boss 40c so as to tilt relative to the main shaft portion 7c, and the slider 16 tilts together with the eccentric shaft portion 307a. As a result, the load acting on the boss 40c increases mainly at two points: point Pa on the base end Br side and point Pb on the open end Bo side opposite point Pa. Therefore, even when the eccentric shaft portion 307a without a crowning structure is employed, the conventional configuration in which the wall thickness of the boss 40c is constant in the boss axial direction can cause problems such as abnormal wear and boss cracking due to increased bearing load, and adding high-strength materials to address these problems can result in increased costs.

[0057] 5, the boss 40c of the present disclosure has a constant inner diameter in the boss axial direction, and is formed so that the wall thickness To at the opening end Bo is thicker than the wall thickness Tm at the central portion Bm in the boss axial direction. This allows the base end Br side of the boss 40c, including point Pa, to deform in accordance with the inclination of the slider 16, improving reliability against wear. Furthermore, the strength of the opening end Bo side of the boss 40c, including point Pb, is improved by the wall thickness To, making the opening end Bo less likely to crack even if the base end Br side of the boss 40c deforms, improving reliability.

[0058] 3, in which the eccentric shaft portion 307a has a crowning structure, and the example of FIG. 10, in which the eccentric shaft portion 307a does not have a crowning structure, there is a difference in that the deformation of the boss 40c starts from the center or end of the eccentric shaft portion 7a in the axial direction. However, both cases have in common the fact that the issues of wear of the boss 40c and cracking of the open end Bo are solved by changing the wall thickness of the boss 40c in the axial direction of the boss.

[0059] Figure 11 is a schematic diagram showing a modified example of the eccentric shaft portion 307a and the boss 40c in the bearing structure of Figure 10. The eccentric shaft portion 307a in Figure 11 is the same as that in Figure 10. That is, the eccentric shaft portion 307a does not have the oscillation shaft side crowning portion 7f, and the eccentric shaft portion 307a has a constant outer diameter in the oscillation axis direction, which is the direction along its central axis As2. The boss 340c in Figure 11 differs from the boss 40c in the examples of Figures 3 and 10 in that the outer peripheral surface 340co of the boss 340c is tapered so that the wall thickness Tb of the boss 340c gradually increases from the base end toward the open end.

[0060] 11 , the boss 340c has a constant inner diameter in the boss axial direction, and the outer peripheral surface 340co of the boss 340c is tapered so that the wall thickness Tb of the boss 340c gradually increases from the base end toward the open end of the boss 340c. This allows the base end Br side of the boss 340c, including point Pa, to deform in accordance with the inclination of the eccentric shaft portion 307a and the slider 16, improving reliability against wear. Furthermore, the open end Bo side of the boss 340c, including point Pb, has improved strength due to the wall thickness, making the open end Bo less likely to crack even if the base end Br side of the boss 340c deforms, improving reliability.

[0061] As described above, the compressor 100 according to the first embodiment includes the shell 2 forming an outer shell, the compression mechanism 5 housed in the shell 2 and forming the compression chamber 5a for compressing the refrigerant, and the drive mechanism 4 housed in the shell 2 and generating rotational motion. The compressor 100 also includes the shaft 7, which connects the drive mechanism 4 and the compression mechanism 5 and transmits the rotational motion of the drive mechanism 4 to the compression mechanism 5, and has a main shaft 7c and an eccentric shaft 7a provided at the end of the compression mechanism 5 side and eccentric with respect to the main shaft 7c, and the cylindrical slider 16 attached to the eccentric shaft 7a. The compression mechanism 5 includes the fixed scroll 30 and the oscillating scroll 40, which is driven by the shaft 7 and oscillates relative to the fixed scroll 30, and which has a cylindrical boss 40c formed therein and on which the slider 16 is slidably disposed. The boss 40c has a constant inner diameter in the boss axial direction, which is the direction along its central axis Ab, and is formed so that the wall thickness To at the opening end Bo is thicker than the wall thickness Tm at the central portion Bm in the boss axial direction.

[0062] In this way, the boss 40c is formed so that the wall thickness To at the open end Bo is thicker than the wall thickness Tm at the central portion Bm in the boss axial direction. This allows the central portion Bm of the boss 40c to deform to follow the shape or inclination of the slider 16, suppressing abnormal wear of the inner circumferential surface 40ci of the boss 40c. Furthermore, the strength of the open end Bo of the boss 40c is improved by the wall thickness To, so cracking of the open end Bo is suppressed even if the central portion Bm of the boss 40c deforms. Therefore, varying the wall thickness of the boss 40c in the boss axial direction can improve the reliability of the boss 40c, eliminating the need to use a high-strength material as in the past to cope with increased bearing loads due to larger capacity. This allows the reliability of the boss 40c to be improved while suppressing increases in cost.

[0063] Additionally, the outer peripheral surface 40co of the boss 40c has an annular step 40cc between the central portion Bm and the open end Bo, and the portion of the boss 40c closer to the open end Bo than the step 40cc has a second outer diameter D2 that is larger than the first outer diameter D1 of the central portion Bm. This makes it easy to make the second outer diameter D2 of the open end Bo larger than the first outer diameter D1 of the central portion Bm simply by providing the step 40cc on the outer peripheral surface 40co, thereby reducing manufacturing costs compared to conventional methods that require equipment for forming high-strength materials.

[0064] Furthermore, the second outer diameter D2 of the boss 40c on the side of the open end Bo from the step 40cc is larger than the first outer diameter D1 of the central portion Bm, but is not more than 1.2 times the first outer diameter D1, thereby achieving a balance between the effect of suppressing cracking of the open end Bo of the boss 40c and ensuring the area of ​​the thrust surface 40b.

[0065] The boss 40c is also configured with a large diameter portion B2 that is closer to the open end Bo than the step 40cc, a small diameter portion B1 that includes a central portion Bm and is closer to the base end Br than the step 40cc, and a connecting portion B3 that connects the large diameter portion B2 and the small diameter portion B1. This minimizes the change in the shape of the boss 40c compared to the conventional configuration, thereby improving the reliability of the boss 40c and reducing costs.

[0066] The length H2 of the large diameter portion B2 in the boss axial direction is 0.1 to 0.4 times the overall length H of the boss 40c in the boss axial direction, which allows a balance to be achieved between the effect of suppressing cracking of the open end Bo of the boss 40c and reducing the number of components of the boss 40c.

[0067] Furthermore, the eccentric shaft portion 7a does not have a crowning structure, and the outer peripheral surface 40co of the boss 40c is formed in a tapered shape so that the wall thickness Tb of the boss 40c gradually increases from the base end toward the open end of the boss 40c. In this way, even when an eccentric shaft portion 7a without a crowning structure is used, the reliability of the boss 40c can be improved simply by changing the outer peripheral surface of the boss 40c compared to the conventional configuration.

[0068] The eccentric shaft portion 7a has a crowning structure. In this case, the slider 16 and the central portion Bm of the boss 40c are deformed in accordance with the crowning structure (oscillating shaft side crowning portion 7f), so the effect of the oscillating shaft side crowning portion 7f in forming a uniform oil film becomes significant.

[0069] Furthermore, the large diameter portion B2 of the boss 40c, which has the second outer diameter D2, has one end (lower end) that is the open end of the boss 40c in the boss axial direction, and the other end (upper end) is arranged so that it does not exceed the end closest to the open end in the portion facing the crowning structure (oscillating shaft-side crowning portion 7f). This means that the range in the boss 40c where the large diameter portion B2 is provided does not overlap with the range in which the crowning structure is provided on the eccentric shaft portion 7a in the boss axial direction, making it easy for the shape of the boss 40c to follow the crowning structure.

[0070] The compressor 100 also includes a frame 306 that is fixed within the shell 2 and rotatably supports the shaft 7, and that has a boss accommodating portion 306d formed therein for accommodating the boss 40c. The inner surface of the boss accommodating portion 306d of the frame 306 (a frame inner surface 306di) is shaped to fit the outer peripheral surface 40co of the boss 40c.

[0071] This allows the area of ​​the thrust surface 40b to be maintained as before, while providing a large diameter portion B2 on the opening end Bo side of the boss 40c, thereby making it possible to improve the reliability of the oscillating bearing structure without reducing the strength against thrust loads.

[0072] Second Embodiment Figure 12 is a vertical cross-sectional view showing the configuration of the boss 240c in the orbiting scroll 240 of the compressor 100 according to the second embodiment. In the second embodiment, the shape of the boss 240c is different from that in the first embodiment. In the compressor 100 according to the second embodiment, parts having the same configuration as those in the first embodiment (particularly the examples of Figures 1 to 6 and Figures 8 to 9) are given the same reference numerals, and their description will be omitted. Items in the compressor 100 according to the second embodiment that are not specifically described will be the same as those in the compressor 100 according to the first embodiment, and the same functions and configurations will be described using the same reference numerals.

[0073] As in the case of the first embodiment, boss 240c in the second embodiment has a constant inner diameter in the boss axial direction, which is the direction along its central axis Ab, and is formed so that the wall thickness To at the opening end Bo is thicker than the wall thickness Tm at the central portion Bm in the boss axial direction. Also, as in the case of the first embodiment, outer peripheral surface 240co of boss 240c has an annular step 40cc, and the portion of boss 240c closer to the opening end Bo than step 40cc has a second outer diameter D2 that is larger than the first outer diameter D1 at the central portion Bm.

[0074] In the second embodiment, the boss 240c is formed so that the wall thickness Tr at the base end Br is greater than the wall thickness Tm at the axial center portion Bm of the boss. The outer peripheral surface 240co of the boss 240c further has an annular base end step 240cd located closer to the base end Br of the boss 240c than the step 40cc. The boss 240c is composed of five portions in the boss axial direction from the thrust surface 40b, i.e., from the base end toward the open end of the boss 240c: a base end large diameter portion B24, a base end connecting portion B25, a small diameter portion B21, an open end connecting portion B23, and an open side large diameter portion B22.

[0075] The opening-side large diameter portion B22 includes the opening end Bo of the boss 240c and is located closer to the opening end Bo than the step 40cc. The small diameter portion B21 includes the center portion Bm of the boss 40c and is located closer to the base end Br than the step 40cc and closer to the opening end Bo than the base end step 240cd. The base end large diameter portion B24 includes the base end Br and is located closer to the base end Br than the base end step 240cd. The opening-side connecting portion B23 is formed on the outer peripheral surface 240co of the boss 240c, where the step 40cc is formed, connecting the opening-side large diameter portion B22 and the small diameter portion B21. The base end connecting portion B25 is formed on the outer peripheral surface 240co of the boss 240c, where the base end step 240cd is formed, connecting the base end large diameter portion B24 and the small diameter portion B21.

[0076] 12, the step 40cc is tapered, and the outer diameter of the opening-side connecting portion B23 gradually increases from the small diameter portion B21 toward the opening-side large diameter portion B22. The base-side step 240cd is curved (e.g., arc-shaped), and the outer diameter of the base-side connecting portion B25 gradually decreases from the base-side large diameter portion B24 toward the small diameter portion B21. The small diameter portion B1 has a constant outer diameter (first outer diameter D1), and the opening-side large diameter portion B22 and the base-side large diameter portion B24 each have a constant outer diameter (second outer diameter D2).

[0077] The configuration of the boss 240c is not limited to the above. The outer peripheral surface 240co of the boss 240c may form right angles at the boundary between the opening-side connecting portion B23 and the small diameter portion B21 and at the boundary between the opening-side connecting portion B23 and the opening-side large diameter portion B22. The outer peripheral surface 240co of the boss 240c may also form right angles at the boundary between the base-side connecting portion B25 and the small diameter portion B21 and at the boundary between the base-side connecting portion B25 and the base-side large diameter portion B24. The outer diameters of the small diameter portion B1, the opening-side large diameter portion B22, and the base-side large diameter portion B24 do not have to be constant. For example, the outer peripheral surfaces 240co of the small diameter portion B21, the opening-side large diameter portion B22, and the base-side large diameter portion B24 may be inclined surfaces inclined relative to the inner peripheral surface 40ci. The outer diameter of the base end large diameter portion B24 may be larger or smaller than the outer diameter (second outer diameter D2) of the opening side large diameter portion B22.

[0078] As described above, in the second embodiment, boss 240c has a constant inner diameter in the boss axial direction, which is the direction along central axis Ab, and is formed so that wall thickness To at opening end Bo is thicker than wall thickness Tm at central portion Bm in the boss axial direction, as in the first embodiment. Thus, in the second embodiment, as in the first embodiment, by configuring boss 240c so that the wall thickness varies in the boss axial direction, abnormal wear of inner circumferential surface 40ci of boss 240c and cracking of opening end Bo of boss 240c can be suppressed without adding high-strength material, and the reliability of boss 240c can be improved while suppressing an increase in cost compared to conventional methods.

[0079] In the second embodiment, the boss 240c is formed so that the wall thickness Tr at the base end Br is greater than the wall thickness Tm at the central portion Bm in the boss axial direction. The outer peripheral surface 240co of the boss 240c has a step 40cc and an annular base end step 240cd provided closer to the base end Br of the boss 240c than the step 40cc. The boss 240c is composed of an opening side large diameter portion B22 that is closer to the opening end Bo than the step portion 40cc, a small diameter portion B21 that includes a central portion Bm and is closer to the base end Br than the step portion 40cc and closer to the opening end Bo than the base end side step portion 240cd, a base end side large diameter portion B24 that is closer to the base end Br than the base end side step portion 240cd, an opening side connecting portion B23 that connects the opening side large diameter portion B22 and the small diameter portion B21, and a base end side connecting portion B25 that connects the base end side large diameter portion B24 and the small diameter portion B21.

[0080] In this way, by making not only the opening end Bo but also the base end Br of the boss 240c thicker than the wall thickness Tm of the central portion Bm, it is possible to align the center of deformation due to load. In addition, since the joint portion between the boss 240c and the base plate 40a in the orbiting scroll 240 is thicker, the bearing strength of the base end Br of the boss 240c is also improved.

[0081] Furthermore, particularly when a shaft 7 having a swing shaft-side crowning portion 7f is used, it is advisable to configure or arrange the boss 240c and the shaft 7 so that the apex position of the arc-shaped swing shaft-side crowning portion 7f is aligned with the center of the small diameter portion B21 in the boss axial direction. This allows the deformation of the boss 240c to follow the deformation of the slider 16.

[0082] The embodiments of the present disclosure are not limited to the above-described first and second embodiments, and various modifications can be made. For example, in the second embodiment, the shape of the inner surface of the boss accommodating portion 6d of the frame 6 may be the same as the shape of the outer peripheral surface 240co of the boss 240c, as shown in the example of FIG. 7 of the first embodiment. Also, for example, in the second embodiment, an eccentric shaft portion 7a without an oscillating-shaft-side crowning portion 7f may be used, as shown in the example of FIG. 10 of the first embodiment. Also, for example, in the second embodiment, an eccentric shaft portion 7a without an oscillating-shaft-side crowning portion 7f may be used, and the outer peripheral surface 240co of the boss 240c may be tapered so that the wall thickness Tb of the boss 240c gradually increases from the base end of the boss 340c toward the open end, as shown in the example of FIG. 11 of the first embodiment.

[0083] Additionally, the compressor 100 has been described as a low-pressure shell compressor in which a low-pressure refrigerant is filled in the shell 2. However, the compressor 100 is not limited to a low-pressure shell compressor, and may also be applied to a high-pressure shell compressor in which a high-pressure refrigerant is filled in the shell 2.

[0084] 2 Shell, 2a Upper shell, 2b Lower shell, 2c Middle shell, 3 Oil pump, 3a Oil reservoir, 4 Drive mechanism, 4a Rotor, 4b Stator, 5 Compression mechanism, 5a Compression chamber, 6 Frame, 6a Main bearing, 6d Boss accommodating portion, 6e Support portion, 6f Oldham accommodating portion, 6s Thrust bearing, 7 Shaft, 7a Eccentric shaft portion, 7b Oil circuit, 7c Main shaft portion, 7d Sub-shaft portion, 7f Oscillating shaft side crowning portion, 7g Main shaft side crowning portion, 8 Fixing device, 11 Intake pipe, 12 Discharge pipe, 13 Discharge chamber, 15 Oldham ring, 15b Pawl, 16 Slider, 16c Hollow portion, 17 Sleeve, 17b Anti-rotation portion, 17c Hollow portion, 20 Sub-frame, 20a Sub-bearing, 21 Seal member, 23 Sub-bearing accommodating portion, 30 Fixed scroll, 30a Base plate, 31 Volute portion, 32 Discharge port, 40 Swing scroll, 40a Base plate, 40b Thrust surface, 40br Base plate Oldham groove, 40c Boss, 40cc Step portion, 40ci Inner peripheral surface, 40co Outer peripheral surface, 40e Swing bearing portion, 41 Volute portion, 51 Reed valve, 53 Valve guard, 100 Compressor, 200 Refrigerant circuit, 201 Condenser, 202 Expansion device, 203 Evaporator, 204 Accumulator, 240 Swing scroll, 240c Boss, 240cd Base end side step portion, 240co Outer peripheral surface, 306 Frame, 306d Boss accommodating portion, 306di Frame inner surface, 306dr Recess, 307a Eccentric shaft part, 340c Boss, 340co Outer circumferential surface, Ab central axis, As1 central axis, As2 central axis, B1 small diameter part, B2 large diameter part, B21 small diameter part, B22 opening side large diameter part, B23 opening side connection part, B24 proximal side large diameter part, B25 proximal side connection part, B3 connection part, Bm Central part, Bo open end, Br proximal end, D1 first outer diameter, D2 second outer diameter, F maximum stress, H total length, H1 length, H2 length of large diameter section, Tb wall thickness, Tm wall thickness, To wall thickness, Tr wall thickness.

Claims

1. A compressor comprising: a shell forming an outer shell; a compression mechanism section contained in the shell and forming a compression chamber for compressing a refrigerant; a drive mechanism section contained in the shell and generating a rotational motion; a shaft connecting the drive mechanism section and the compression mechanism section and transmitting the rotational motion of the drive mechanism section to the compression mechanism section, the shaft having a main shaft section and an eccentric shaft section provided at an end of the compression mechanism section side and eccentric with respect to the main shaft section; and a cylindrical slider attached to the eccentric shaft section, the compression mechanism section having: a fixed scroll; and an oscillating scroll operated by the shaft and performing an oscillating motion relative to the fixed scroll, the boss having a constant inner diameter in the boss axial direction which is a direction along the central axis of the boss, and formed so that the wall thickness at the open end is thicker than the wall thickness at the center in the boss axial direction.

2. The compressor according to claim 1, wherein the outer peripheral surface of the boss has an annular step between the central portion and the open end, and the boss on the side of the open end from the step has a second outer diameter larger than the first outer diameter of the central portion.

3. The compressor according to claim 2, wherein the second outer diameter of the boss on the side of the opening end from the step is larger than the first outer diameter of the central portion and is 1.2 times or less the first outer diameter.

4. A compressor as claimed in claim 2 or 3, wherein the boss is composed of a large diameter portion which is closer to the opening end than the step portion, a small diameter portion which includes the central portion and is closer to the base end than the step portion, and a connecting portion which connects the large diameter portion and the small diameter portion.

5. The compressor according to claim 4, wherein the length H2 of the large diameter portion in the boss axial direction is 0.1 to 0.4 times the overall length H of the boss in the boss axial direction.

6. A compressor according to claim 2 or 3, wherein the boss is formed so that the wall thickness at the base end is thicker than the wall thickness at the central portion in the boss axial direction.

7. The compressor according to claim 6, wherein the outer peripheral surface of the boss has the step and an annular base end side step provided on the base end side of the step, and the boss is composed of: an opening side large diameter section constituting the opening end side of the step; a small diameter section including the central section and constituting the base end side of the step and the opening end side of the base end side of the opening end; a base end side large diameter section constituting the base end side of the base end side of the step; an opening side connecting section connecting the opening side large diameter section and the small diameter section; and a base end side connecting section connecting the base end side large diameter section and the small diameter section.

8. The compressor according to claim 1, wherein the eccentric shaft portion does not have a crowning structure, and the outer peripheral surface of the boss is tapered so that the wall thickness of the boss gradually increases from the base end to the open end of the boss.

9. A compressor as claimed in any one of claims 2 to 7, wherein the eccentric shaft portion has a crowning structure.

10. The compressor according to claim 9, wherein the large diameter portion of the boss having the second outer diameter has an open end of the boss in the boss axial direction as one end, and the other end does not exceed the end closest to the open end in a portion facing the crowning structure.

11. A compressor as claimed in any one of claims 1 to 10, comprising a frame fixed within the shell to rotatably support the shaft, the frame having a boss accommodating section in which the boss is accommodated, the inner surface of the boss accommodating section of the frame being shaped to follow the outer circumferential surface of the boss.

12. The compressor according to any one of claims 1 to 11, wherein the slider is made of sintered metal.

13. The compressor according to any one of claims 1 to 12, wherein an oscillating bearing portion made of a composite metal containing a resin material is provided on the inner peripheral surface of the boss.

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