WO2013179658A1

WO2013179658A1 - Compressor

Info

Publication number: WO2013179658A1
Application number: PCT/JP2013/003382
Authority: WO
Inventors: 裕文吉田; 雄司尾形; 優塩谷; 大輔船越; 啓晶中井; 健苅野
Original assignee: パナソニック株式会社
Priority date: 2012-05-29
Filing date: 2013-05-29
Publication date: 2013-12-05
Also published as: CN103782040A; CN103782040B; EP2857690A1; JP6176577B2; JPWO2013179658A1; EP2857690B1; EP2857690A4

Abstract

A compressor has a drive shaft (3) supported by an upper bearing (7) and a lower bearing (9), a discharge port (22) provided in the lower bearing (9), and a lower discharge space (15b) composed of the lower bearing (9) and a lower valve cover (16b) for receiving hydraulic fluid compressed in a lower compression chamber (11b) and discharged from the discharge port (22). An oil holding unit (24) is provided adjacent to the lower discharge space (15b) which has a configuration that receives some of the oil stored in a sealed container (1) with an oil reservoir (19) in the bottom portion but suppresses the flow of the received oil more than the flow of the oil in the oil reservoir (19). Because the lower end surface of a boss (9a) in the central portion of the lower bearing (9) has a height which is equal to or lower than the lowest surface of the lower valve cover (16b), gas does not accumulate in the lower end portion of the drive shaft (3) which draws in the oil used to lubricate and seal the compression mechanism internally, thereby providing a compressor that is both highly efficient and highly reliable.

Description

Compressor

The present invention relates to a compressor used in an air conditioner, a refrigerator, a blower, a water heater, and the like.

An example of a conventional configuration will be described with reference to a longitudinal sectional view of a two-cylinder rotary type high-pressure hermetic compressor shown in FIG.

In FIG. 4, the upper and

lower cylinders

101 and 102, the upper and lower

rolling pistons

103 and 104, and the vanes (not shown) are sandwiched between the upper bearing 105, the middle plate 106, and the lower bearing 107, thereby providing two suction chambers that are independent from each other. 108a (108b (not shown)) and two compression chambers 109b (109a (not shown)) are formed. The compression mechanism 111 and the electric element 112 are accommodated in the sealed container 113. The compression mechanism 111 performs a compression operation by rotating the upper and lower

rolling pistons

103 and 104 as the drive shaft 110 rotates. The electric element 112 transmits a rotational force to the drive shaft 110.

The upper bearing 105 and the lower bearing 107 are each provided with a discharge port (not shown), and the working fluid compressed to a predetermined pressure in the compression chamber 109b (109a (not shown)) is a check valve (not shown). From the discharge port. Upper and

lower discharge spaces

114 and 115 on the downstream side of the discharge port are formed by being surrounded by upper and

lower bearings

105 and 107 and upper and lower valve covers 116 and 117. The working fluid in the lower discharge space 115 is guided to the upper discharge space 114 through an upper and lower communication path (not shown), and merges with the working fluid discharged from the discharge port of the upper bearing 105. Thereafter, the working fluid flows out into the lower space of the electric element 112 through the opening provided in the upper valve cover 116 and is discharged from the discharge pipe 118 at the upper part of the hermetic container 113 to the outside of the compressor.

The oil stored in the lower part of the hermetic container 113 is sucked up from the lower end of a hole provided in the axial direction inside the drive shaft 110, and an appropriate amount is supplied to various parts of the compression mechanism unit 111 to lubricate the sliding part and the compression chamber 109b (109a (not shown)) is used for a gap seal.

The inside of the lower discharge space 115 is filled with the discharge gas having the highest temperature among the compressors, so that the lower bearing 107 receives heat. Along with this, the low-temperature and low-pressure working fluid in the lower suction chamber 108b is also received heat, and volume efficiency reduction due to heat reception is a problem.

In order to solve this problem, in the compressor shown in Patent Document 1, a stagnation space 119 is provided on the lower suction chamber 108b side in the lower discharge space 115 of the lower bearing 107 as shown in FIG. The space 119 is communicated with the passage 120. Accordingly, the discharge gas of high temperature and high pressure is moved away from the lower suction chamber 108b to reduce heat reception and improve the volume efficiency.

However, in this configuration, since the lower discharge space 115 filled with the hottest gas immediately after discharge from the discharge port and the stagnation space 119 communicate with each other, the exchange of gas inside and outside the stagnation space 119 occurs. The effect is limited.

Here, if the sealing performance with the lower valve cover 117 at the center of the lower bearing 107 is poor, the gas in the lower discharge space 115 leaks out from the sealing portion and is sucked up together with oil from the lower end of the drive shaft. Therefore, the lubrication deterioration of the sliding part due to insufficient oil supply and the sealing performance of the compression chamber 109b are also problems.

In order to solve this problem, in the compressor shown in Patent Document 2, as shown in FIG. 6, in the fastening surface 122 between the lower bearing 107 and the lower valve cover 117, the center side fastening surface 122b with respect to the outer circumferential side fastening surface 122a. Protrudes by a height L1. Therefore, the contact force at the center side fastening surface 122b is increased to improve the sealing performance, and the suction of gas from the lower end of the drive shaft 110 is prevented to improve the reliability.

JP 2009-2299 A JP 2009-127608 A

However, in this configuration, the lower valve cover 117 is positively deformed to generate an axial contact force. For this reason, the lower bearing 107 is deformed by applying an axial load, so that a clearance with the rolling piston cannot be ensured, or the cylindricity or perpendicularity of the bearing portion is impaired, and the reliability is deteriorated. There is a case.

Further, since the lower valve cover 117 needs to be thinned to some extent, gaps are likely to be generated at various locations on the fastening surface 122.

Further, there may be a gap near the middle between the center side fastening surface 122b sealed at the edge and the outer side fastening surface 122a to which the bolt is fastened.

The present invention solves the above-mentioned conventional problems, wherein the oil holding part takes in a part of the oil stored in a closed container having an oil reservoir in the lower part, and the flow of the taken-in oil flows into the oil reservoir. In a compressor that is configured to be suppressed (restricted) rather than flow, and in which the oil retaining portion is arranged adjacent to the lower discharge space or through a partition region, the lower valve of the lower end surface of the boss at the center of the lower bearing By making it the same height as the lowermost surface of the cover or below it, the recess near the center portion of the lower bearing is eliminated, and gas engagement of the drive shaft is prevented. Accordingly, it is an object to provide a compressor having high volume efficiency due to the heat insulation effect and high reliability without gas biting.

Therefore, in order to solve the conventional problem, a compressor according to the present invention includes a sealed container having an oil reservoir, an upper bearing that supports a drive shaft, and a lower bearing in the sealed container. A bearing, a discharge port that is provided in the lower bearing and discharges the working fluid compressed in a compression chamber, an oil holding portion that is provided in the lower bearing and takes in part of the oil in the oil reservoir, and the lower bearing And a lower valve cover, provided in the lower bearing so as to independently separate a discharge space into which the compressed working fluid is discharged through the discharge port, and the oil holding portion and the discharge space. The lower valve cover is attached to a fastening surface provided in the partition area, and a lower end surface of a central portion of a boss through which the drive shaft passes is the lower valve. Bottom of cover Or the same height as the, is characterized in that the position from the lower side thereto.

As a result, in a configuration using a lower bearing and a lower valve cover having an oil retaining portion having a high heat insulating effect, gas may stay in the lower end portion of the drive shaft that sucks up oil used for lubrication and sealing in the compression mechanism portion. Disappear. Therefore, it is possible to prevent deterioration in reliability and reduction in compressor efficiency due to gas biting.

In the compressor according to the present invention, in the configuration using the lower bearing and the lower valve cover having an oil holding portion having a high heat insulating effect, gas is generated at the lower end portion of the drive shaft that sucks up oil used for lubrication and sealing in the compression mechanism portion. A compressor that has both high efficiency and high reliability can be provided by preventing stagnation and preventing deterioration in reliability and reduction in compressor efficiency due to gas biting.

The longitudinal cross-sectional view of the compressor in Embodiment 1 of this invention Sectional drawing of the lower bearing in Embodiment 1 of this invention The front view of the lower bearing in Embodiment 1 of this invention A longitudinal sectional view of a compressor in a conventional compressor Front view of lower bearing in conventional compressor of Patent Document 1 Sectional view of lower bearing in conventional compressor of Patent Document 2

DESCRIPTION OF SYMBOLS 1 Airtight container 3 Drive shaft 4 Compression mechanism part 7 Upper bearing 9 Lower bearing 9a Boss 11a Upper compression chamber 11b Lower compression chamber 15a Upper discharge space 15b Lower discharge space (discharge space)
16b Lower valve cover 19 Oil reservoir 22 Discharge port 24 Oil holding part 25 Bulkhead (partition area)
26 Fastening surface

1st invention discharges the working fluid which was provided in the airtight container which has an oil sump, the upper bearing and lower bearing which support a drive shaft in the airtight container, and the lower bearing, and was compressed by the compression chamber A discharge port, an oil holding portion that is provided in the lower bearing and takes in a part of the oil in the oil reservoir, the lower bearing and a lower valve cover, and is compressed through the discharge port Is a compressor comprising: a discharge space from which the oil is discharged; and a partition region provided in the lower bearing so as to partition the oil holding portion and the discharge space independently, wherein the lower valve cover is A lower end surface of a central portion of a boss that is attached to a fastening surface provided in the partition region and through which the drive shaft passes is located at the same height as or below the lowermost surface of the lower valve cover. As a result, there is no gas stagnation in the vicinity of the oil suction port at the lower end of the drive shaft, and it is possible to prevent the deterioration of the lubrication of the bearing portion and the deterioration of the seal of the compression chamber due to gas biting, thereby realizing high reliability.

In the second invention, in particular, in the compressor of the first invention, the fastening surface of the lower bearing to which the lower valve cover is attached is the same plane perpendicular to the central axis of the lower bearing. Thereby, since the shape of a lower bearing becomes simple, workability can be improved and processing cost can be reduced. As a result, the processing accuracy of the fastening surface is improved, the sealing performance on the fastening surface is improved, and deterioration of reliability due to gas biting can be suppressed.

In addition, even if the fastening surface is constituted by a plurality of flat surfaces by providing a step or the like, the workability is high and the same effect can be obtained.

In the third invention, in particular, in the compressor of the first or second invention, the central axis of the outer diameter of the boss does not coincide with the central axis of the inner diameter. As a result, a sufficient seal length is secured on the fastening surface at the center of the fastening surface between the lower bearing and the lower valve cover, or the boss is thickened at a position where the load on the lower bearing is high. In addition, it is possible to freely design the shape of the boss, and it is possible to ensure high reliability.

In the fourth invention, in particular, in the compressor according to any one of the first to third inventions, a seal material is provided between the lower bearing and the lower valve cover. As a result, variations in component accuracy such as flatness and surface roughness of the fastening surfaces of the lower bearing and the lower valve cover can be absorbed, sealing performance can be improved reliably, and reliability can be ensured. .

In the compressor according to any one of the first to fourth inventions, the working fluid is compatible with the lubricating oil. Accordingly, the working fluid is dissolved in the lubricating oil discharged to the outside of the compressor to lower the lubricating oil viscosity and facilitate return to the inside of the compressor, thereby ensuring the oil level inside the compressor. However, if the compatibility is high, the lubricating oil is foamed under reduced pressure due to the pressure drop during the compressor operation transient, and a large amount of gas is released. Even in such a case, in the present invention, since gas does not stay at the lower end of the drive shaft, high reliability can be maintained.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a longitudinal sectional view of a compressor according to Embodiment 1 of the present invention.

In FIG. 1, the electric element 2 is accommodated in the sealed container 1. The compression mechanism unit 4 is driven by the vertical drive shaft 3 of the electric element 2. The compression mechanism 4 includes an upper cylinder 5a, an upper rolling piston 6a, and an upper vane (not shown) sandwiched between an upper bearing 7 and an intermediate plate 8, and a lower cylinder 5b, a lower rolling piston 6b, and a lower vane (not shown). Is sandwiched between the middle plate 8 and the lower bearing 9. Accordingly, the upper and

lower cylinders

5a and 5b form independent upper and lower suction chambers 10a and 10b and upper and lower compression chambers 11a and 11b, respectively, and perform a compression operation. In the upper and

lower cylinders

5a and 5b, upper and lower

eccentric parts

3a and 3b configured integrally with the drive shaft 3 are accommodated, and the upper and lower

eccentric parts

3a and 3b are provided with upper and lower rolling pistons. 6a and 6b are rotatably mounted. The upper and

lower cylinders

5a and 5b are provided with vanes (not shown) in contact with the upper and

lower rolling pistons

6a and 6b, and partition the suction chamber 10 and the compression chamber 11. The upper and

lower cylinders

5a and 5b are provided with upper and

lower suction holes

12a and 12b adjacent to the upper suction chamber 10a (lower suction chamber 10b (not shown)). The

suction liners

13a and 13b are press-fitted into the upper and

lower suction holes

12a and 12b. The

suction liners

13a and 13b receive the high-pressure refrigerant gas inside the sealed container 1 and the low-pressure refrigerant gas inside the upper and

lower suction holes

12a and 12b. Partitioning. An accumulator 14 is connected to the

suction liners

13a and 13b while maintaining airtightness in order to prevent liquid compression of the compressor.

When the electric element 2 is energized and the drive shaft 3 is rotated, the upper and lower

eccentric parts

3a and 3b rotate eccentrically in the upper and

lower cylinders

5a and 5b, and the upper and

lower rolling pistons

6a and 6b become vanes. Rotating motion while abutting, refrigerant gas suction and compression are repeated.

The upper and

lower discharge spaces

15a and 15b are formed by fastening the upper bearing 7 and the upper valve cover 16a, and the lower bearing 9 and the lower valve cover 16b, respectively. The gases compressed by the upper and

lower cylinders

5a and 5b are discharged from discharge ports (not shown) provided in the upper bearing 7 and the lower bearing 9 to the upper and

lower discharge spaces

15a and 15b. The upper and lower communication passages (not shown) pass through the five parts of the upper bearing 7, the upper and

lower cylinders

5 a and 5 b, the middle plate 8, and the lower bearing 9. The discharge gas in the lower discharge space 15b is guided into the upper discharge space 15a through the upper and lower communication passages, merges with the discharge gas compressed by the upper cylinder 5a, and then passes through the discharge passage 17 and the lower part of the electric element 2 It flows out into space. Thereafter, the electric element 2 is guided to the upper space of the electric element 2 through the outer peripheral portion of the stator 2a, the gas passage provided inside the rotor 2b, and the gap between the stator 2a and the rotor 2b, and discharged. It is discharged from the pipe 18 to the outside of the compressor.

A hole is provided in the drive shaft 3, and the oil supply mechanism 20 is attached to the lower end of the drive shaft 3. The oil in the oil reservoir 19 at the lower part of the sealed container 1 is sucked up from the oil suction port 21 by using the oil supply mechanism 20. The sucked-up oil is supplied to various portions of the compression mechanism section 4 to lubricate the sliding section and seal the gap between the lower compression chamber 11b (11a (not shown)).

2 is a cross-sectional view of the lower bearing in FIG. 1, and FIG. 3 is a front view of the lower bearing.

The high-temperature and high-pressure discharge gas compressed by the lower cylinder 5b is discharged to the lower discharge space 15b through the discharge port 22. A check valve (not shown) is attached to the discharge port 22 to prevent the discharge gas from flowing back into the lower compression chamber 11b.

The discharge gas in the lower discharge space 15b is guided from the vertical communication path 23 to the upper discharge space 15a.

An oil retaining portion 24 is provided on the lower suction hole 12b side, and a partition wall (partition region) 25 is in close contact with the lower valve cover 16b to seal the surface, thereby isolating the lower discharge space 15b and the oil retaining portion 24 from each other. . Further, the oil holding part 24 communicates with the oil reservoir 19 through a minute passage (not shown), but the oil hardly flows between the oil holding part 24 and the oil reservoir 19.

The lower end surface of the boss 9a at the center of the lower bearing 9 is below the lower surface of the lower valve cover 16b.
Further, the center axis 9a1 of the outer diameter of the boss 9a and the center axis 9a2 of the inner diameter are shifted. The center length 9a1 of the outer diameter of the boss 9a and the center axis 9a2 of the inner diameter do not coincide with each other, so that the seal length of the fastening surface 26 between the lower bearing 9 and the lower valve cover 16b is particularly sufficient at the fastening surface 26 on the center side. It is possible to freely design the shape of the boss 9a, such as ensuring the thickness of the boss 9a at a position where the load of the lower bearing 9 is high, and ensuring high reliability.

3, the outer diameter center of the boss 9 a is eccentric to the lower right with respect to the center of the lower bearing 9.

About the compressor comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

The low-temperature and low-pressure gas enters the compression mechanism section 4 through the upper and

lower suction holes

12a and 12b, is compressed and exits from the compression mechanism section 4, and is then discharged from the discharge pipe 18 to the outside of the compressor. In the process, the gas inside the lower discharge space 15b, that is, the discharge gas immediately after being discharged from the discharge port 22, is the highest temperature and pressure in most operation modes, and the upper bearing 7 and the lower bearing 9 are at this high temperature and pressure. Always exposed to the discharge gas.

On the other hand, the upper bearing 7 and the lower bearing 9 that function as one of the parts forming the upper suction chamber 10a (lower suction chamber 10b (not shown)) filled with the low-temperature and low-pressure suction gas are further exposed to the low-temperature and low-pressure suction gas. Has been.

Therefore, the heat of the high-temperature and high-pressure discharge gas is transferred to the low-temperature and low-pressure suction gas by heat transfer and heat conduction, resulting in a deterioration in volumetric efficiency of the compressor due to a reduction in the density of the suction gas.

In order to suppress this heat transfer, an oil holding portion 24 as a heat insulating layer is provided on the lower suction chamber 10b side of the lower bearing 9 to improve the volume efficiency.

The fastening surface 26 between the lower bearing 9 and the lower valve cover 16b is roughly divided into five seal portions (the following first to fifth seal portions 26a to 26e). Any of the seal portions 26a to 26e maintains the sealing performance by the face seal. The leakage risks at the respective seal portions 26a to 26e are different.
It should be noted that a sealing material (not shown) is preferably provided on the fastening surface 26 between the lower bearing 9 and the lower valve cover 16b, that is, the seal portions 26a to 26e.

The first seal part 26a is a surface where the two partition walls 25 between the lower discharge space 15b and the oil holding part 24 come into contact with the lower valve cover 16b. The lower discharge space 15b and the oil holding part 24 are partitioned.

Since the pressure in the lower discharge space 15b is slightly higher than that in the oil holding portion 24, the discharge gas in the lower discharge space 15b flows into the oil holding portion 24 when the sealing performance of the first seal portion 26a is impaired. As a result, since the oil retaining part 24 itself becomes high temperature, the function as the heat insulating layer cannot be performed, and the volume efficiency is deteriorated. Therefore, it is necessary to securely seal the first seal portion 26a.

The second seal portion 26b is a surface on the oil retaining portion 24 side of the fastening surface 26 on the outer periphery of the lower bearing 9. The oil holding part 24 and the oil reservoir 19 are partitioned.

Since the minute passage is provided between the oil holding part 24 and the oil reservoir 19 as described above and is basically in a communicating state, even if the sealing performance of the second seal part 26b is slightly impaired, there is a particular problem. There is no. However, if the sealing performance is extremely deteriorated, the high-temperature oil in the oil reservoir 19 enters the oil retaining portion 24 and the heat insulation performance is deteriorated.

The third seal portion 26 c is a surface on the lower discharge space 15 b side of the fastening surface 26 on the outer periphery of the lower bearing 9. The lower discharge space 15b and the oil reservoir 19 are partitioned.

Since the pressure in the lower discharge space 15 b is slightly higher than that in the oil reservoir 19, the discharge gas in the lower discharge space 15 b flows into the oil reservoir 19 when the sealing performance of the third seal portion 26 c is impaired. As a result, dissolution of the discharge gas in the oil is promoted, the oil viscosity is lowered, and the reliability of the compressor is lowered. Therefore, it is necessary to securely seal the third seal portion 26c.

The fourth seal portion 26d is a surface on the oil retaining portion 24 side of the fastening surface 26 on the center side of the lower bearing 9. The oil holding part 24 and the oil reservoir 19 are partitioned.

As with the second seal portion 26b, the fourth seal portion 26d has no particular problem even if the sealing performance is slightly impaired.

The fifth seal portion 26e is a surface on the lower discharge space 15b side of the fastening surface 26 on the center side of the lower bearing 9. The lower discharge space 15b and the oil reservoir 19 are partitioned.

When the sealing performance of the fifth seal portion 26e is impaired, there is a risk of a decrease in oil viscosity due to the discharge gas being dissolved in the oil as in the case of the third seal portion 26c. Furthermore, so-called gas biting occurs in which the gas flowing out from the fifth seal portion 26 e is directly sucked from the oil suction port 21 of the drive shaft 3. As a result, the lubrication of the sliding portion due to the insufficient amount of oil supply or the seal of the compression chamber 11 is insufficient, resulting in an extreme deterioration in reliability and a reduction in compressor efficiency. Therefore, it is necessary to pay special attention to the sealing property of the fifth seal portion 26e.

That is, the key point for realizing high reliability and efficiency of the compressor is not to generate gas at the oil suction port 21 of the drive shaft 3.

The lower valve cover 16b is made of a relatively thick material, so that the radial deformation and circumferential deformation of the lower valve cover 16b due to bolt fastening are suppressed. This improves the sealing performance at the first seal portion 26a, the third seal portion 26c, and the fifth seal portion 26e that need to be reliably sealed.

The deformation due to the pressure difference between the lower discharge space 15b and the oil reservoir 19 can be minimized because the lower valve cover 16b is relatively thick, and the deterioration of the sealing performance of the fifth seal portion 26e due to the curvature of the central portion of the lower valve cover 16b is suppressed. can do.

Even if the sealing performance of the fifth seal portion 26e is impaired and gas is released, it is discharged to a position higher than the oil suction port 21 of the drive shaft 3. Therefore, the gas flows to the oil surface side of the oil reservoir 19 due to the buoyancy of the bubbles, and is not sucked from the oil suction port 21.

In addition, by decentering the outer diameter center of the boss 9a from the center of the lower bearing 9, the seal length of the fifth seal portion 26e can be set relatively long, so that the sealing performance of the fifth seal portion 26e is further improved. To do.

Further, since the thickness of the boss 9a in the eccentric direction can be made relatively thick, by making the load direction due to the compression load and the eccentric direction substantially coincide with each other, the deformation of the boss 9a due to the bearing load is suppressed, It is also possible to prevent abnormal wear.

In addition, by using the lower bearing 9 as a sintered material, it becomes easy to process the eccentric boss 9a, and an increase in processing cost can be suppressed.

In the present embodiment, a two-cylinder rotary compressor having two cylinders at the top and bottom has been described as an example, but the same effect can be obtained with a one-cylinder rotary compressor in which the lower bearing 9 includes the discharge port 22. Further, if the fifth seal portion 26e and the oil suction port 21 are close to each other, the same effect can be obtained even with a scroll compressor.

As described above, the compressor according to the present invention is used for lubrication and sealing in the compression mechanism portion in the configuration using the lower bearing having the oil retaining portion having a high heat insulating effect and the lower valve cover having a relatively large thickness. Gas no longer stays at the lower end of the drive shaft that sucks up oil. Accordingly, it is possible to realize a compressor having both high efficiency and high reliability by preventing deterioration in reliability and reduction in compressor efficiency due to gas biting. The present invention can also be applied to applications such as air conditioners and heat pump water heaters using HFC refrigerants, HCFC refrigerants, or HFO refrigerants, or air conditioners and heat pump water heaters using natural refrigerant carbon dioxide.

Claims

An airtight container having an oil sump;
An upper bearing and a lower bearing for supporting the drive shaft in the sealed container;
A discharge port that is provided in the lower bearing and discharges the working fluid compressed in the compression chamber;
An oil holding portion that is provided in the lower bearing and takes in part of the oil in the oil reservoir;
A discharge space configured by the lower bearing and the lower valve cover, in which the compressed working fluid is discharged through the discharge port;
A partition region provided in the lower bearing in order to partition the oil holding portion and the discharge space independently;
A compressor comprising:
The lower valve cover is attached to a fastening surface provided in the partition region, and the lower end surface of the central portion of the boss through which the drive shaft passes is the same height as the lowermost surface of the lower valve cover or positioned below it. The compressor characterized by doing.
The compressor according to claim 1, wherein a fastening surface of the lower bearing to which the lower valve cover is attached is the same plane perpendicular to the central axis of the lower bearing.
3. The compressor according to claim 1, wherein a central axis of the outer diameter of the boss does not coincide with a central axis of the inner diameter.
The compressor according to any one of claims 1 to 3, wherein a sealing material is provided between the lower bearing and the lower valve cover.
The compressor according to any one of claims 1 to 4, wherein the working fluid is compatible with lubricating oil.