Refrigerant compressor, refrigeration cycle device provided with refrigerant compressor, and method for manufacturing refrigerant compressor

Abstract

Provided is a refrigerant compressor in which accumulation of refrigerating machine oil in a sliding part can be suppressed while maintaining low compatibility between an R290 refrigerant and the refrigerating machine oil. This scroll compressor comprises: a compression mechanism that compresses the R290 refrigerant; a drive shaft that transmits power to the compression mechanism; a sliding bearing (200) that pivotally supports a drive bearing; a casing that accommodates the compression mechanism, the drive bearing, and the sliding bearing; and refrigeration machine oil stored in the casing. The refrigerating machine oil is PAG, POE, or PVE having an OH group at a terminal of a chemical structure. This sliding bearing has a composite material CM including a resin-impregnated layer (220) in which a porous metal M is impregnated with a resin P containing PTFE. A sliding surface (222) of the sliding bearing is composed of the resin-impregnated layer, and metal is exposed at a predetermined metal exposure ratio. The surface energy of the surface of the resin-impregnated layer of the composite material at the predetermined metal exposure ratio is less 40 mN / m.

Description

Refrigerant Compressor, Refrigeration Cycle Device Comprising the Refrigerant Compressor, and Method for Manufacturing the Refrigerant Compressor

[0001] The present disclosure relates to a refrigerant compressor, a refrigeration cycle device including the refrigerant compressor, and a method for manufacturing the refrigerant compressor.

[0002] From the perspective of suppressing global warming, for example, as disclosed in Patent Document 1 (International Publication No. 2017 / 72867), the application of an R290 refrigerant (propane refrigerant) with a small global warming potential to a refrigeration cycle device has been promoted.

[0003] The R290 refrigerant has excellent properties such as a small global warming potential. In addition, the R290 refrigerant is specified as CLASS 3 (strongly flammable) in ISO 817:2014 (Refrigerants - Designation and safety classification), and has the property of being flammable. Therefore, from the perspective of safety, it is preferable that the filling amount of the R290 refrigerant in the refrigeration cycle device is as small as possible.

[0004] By the way, in the refrigerant compressor of the refrigeration cycle device, for lubrication of the sliding part, refrigeration oil is filled together with the refrigerant. Generally, hydrocarbon-based refrigerants such as the R290 refrigerant have high compatibility with refrigeration oil. When a large amount of the R290 refrigerant dissolves in the refrigeration oil, there is a problem that it is necessary to increase the amount of refrigerant to be filled in the refrigeration cycle device, which is contrary to the goal of reducing the usage amount of the R290 refrigerant.

[0005] As a countermeasure to such a problem, refrigeration oil having a terminal OH group can be used. This is because the refrigerant base oil having a terminal OH group has high polarity, while the R290 refrigerant has low polarity, so the compatibility between the R290 refrigerant and the refrigeration oil becomes low.

[0006] However, when using such refrigeration oil having a terminal OH group, while the merit of suppressing an increase in the usage amount of the R290 refrigerant can be obtained, since it is difficult for the R290 to mix with the refrigeration oil, it is difficult to reduce the viscosity of the refrigeration oil.

[0007] Therefore, it is preferable that the refrigerant oil supplied for lubrication of the sliding parts of the refrigerant compressor be discharged from the sliding parts as quickly as possible after lubrication, but it tends to remain in the sliding parts. As a result, if refrigerant oil having terminal OH groups is used, the temperature of the sliding parts and the components located around the sliding parts may rise beyond the appropriate temperature range, which may reduce the reliability of the refrigerant compressor.

[0008] Therefore, in order to reduce the amount of R290 refrigerant used, there is a need for a refrigerant compressor that can maintain low compatibility between R290 refrigerant and refrigerant oil, while also suppressing the retention of refrigerant oil in the sliding parts.

[0009] The refrigerant compressor according to the first aspect comprises a compression mechanism, a drive shaft, a cylindrical sliding bearing, a casing, and refrigerant oil. The compression mechanism compresses R290 refrigerant (propane refrigerant). The drive shaft transmits power to the compression mechanism. The sliding bearing supports the drive shaft. The casing houses the compression mechanism, the drive shaft, and the sliding bearing. The refrigerant oil is stored in the casing. The refrigerant oil is PAG (polyalkylene glycol), POE (polyol ester), or PVE (polyvinyl ether), which have OH groups at the ends of their chemical structure. The sliding bearing has a composite material including a resin-impregnated layer in which a resin containing PTFE is impregnated into a porous metal. The sliding surface of the sliding bearing is composed of the resin-impregnated layer, with the metal exposed at a predetermined metal exposure rate. At the predetermined metal exposure rate, the surface energy at the surface of the resin-impregnated layer of the composite material is less than 40 mN / m.

[0010] When the surface energy of the sliding surface of a plain bearing is high, refrigerant oil tends to remain in the sliding area between the plain bearing and the drive shaft.

[0011] In contrast, the refrigerant compressor according to the first viewpoint uses a sliding bearing that keeps the surface energy of the sliding surface low, so that the refrigerant oil can be quickly discharged from the sliding part between the sliding bearing and the drive shaft, thereby suppressing the temperature rise of the components that make up the sliding part between the sliding bearing and the drive shaft.

[0012] The refrigerant compressor relating to the second aspect is the refrigerant compressor relating to the first aspect, wherein the predetermined metal exposure rate is in the range of 5% to 80%.

[0013] In the second type of refrigerant compressor, ensuring a minimum metal exposure rate of 5% makes it easier to ensure the wear resistance of the sliding bearings. On the other hand, in the second type of refrigerant compressor, limiting the metal exposure rate to 80% or less can suppress the surface energy of the sliding surface of the sliding bearing to less than 40 mN / m.

[0014] The refrigerant compressor relating to the third aspect is the refrigerant compressor relating to the second aspect, wherein the predetermined metal exposure rate is in the range of 30% to 60%.

[0015] In the third-party refrigerant compressor, by ensuring a metal exposure rate of 30% or more, relatively high wear resistance of the sliding bearings can be ensured, while limiting the metal exposure rate to 60% or less can suppress the surface energy of the sliding surface of the sliding bearings to a relatively low level.

[0016] The refrigerant compressor relating to the fourth aspect is a refrigerant compressor relating to any of the first, third, or fourth aspects, wherein the surface energy at the surface of the resin-impregnated layer of the composite material at a predetermined metal exposure rate is less than 35 mN / m.

[0017] In the refrigerant compressor relating to the fourth aspect, since a sliding bearing is used in which the surface energy of the sliding surface is kept below 35 mN / m, the refrigerant oil can be quickly discharged from the sliding part, and the temperature rise of the components constituting the sliding part can be suppressed.

[0018] The refrigerant compressor relating to the fifth aspect is the refrigerant compressor relating to the fourth aspect, wherein the surface energy at the surface of the resin-impregnated layer of the composite material at a predetermined metal exposure rate is less than 30 mN / m.

[0019] In the refrigerant compressor relating to the fifth aspect, in particular, a sliding bearing is used in which the surface energy of the sliding surface is further reduced to less than 30 mN / m, so that refrigerant oil can be quickly discharged from the sliding part and the temperature rise of the components constituting the sliding part can be suppressed.

[0020] The refrigeration cycle device relating to the sixth aspect comprises a refrigerant compressor according to either the first or fifth aspect.

[0021] The refrigeration cycle system related to the sixth perspective can realize a highly reliable refrigeration cycle system.

[0022] The method for manufacturing a refrigerant compressor according to the seventh perspective is the method for manufacturing a refrigerant compressor according to any of the first to fifth perspectives. The manufacturing method comprises the steps of processing a composite material that will become a sliding bearing into a cylindrical shape, and cutting the resin-impregnated layer that constitutes the sliding surface of the sliding bearing, and setting the metal exposure rate of the cut surface to a predetermined metal exposure rate.

[0023] In the method for manufacturing a refrigerant compressor relating to the seventh aspect, by setting the sliding surface of the sliding bearing to a predetermined metal exposure ratio, a sliding bearing can be realized in which the surface energy of the sliding surface is suppressed to less than 40 mN / m. In the refrigerant compressor, refrigerant oil can be quickly discharged from the sliding part between the sliding bearing and the drive shaft, thereby suppressing the temperature rise of the components constituting the sliding part between the sliding bearing and the drive shaft.

[0024] This is a schematic diagram of an air conditioner according to one embodiment of a refrigeration cycle device. This is a schematic cross-sectional view of a scroll compressor, an example of a refrigerant compressor used in the air conditioner shown in Figure 1. This is a schematic diagram showing a cross-section of the composite material used in the sliding bearing of the scroll compressor shown in Figure 2 before machining. This is an enlarged view of a part of the cross-section of a cylindrical sliding bearing cut in a direction perpendicular to the axial direction of the cylinder. This is a graph plotting the measured surface energy values ​​when the metal exposure rate on the surface of the resin-impregnated layer of the composite material is changed. This is a schematic flowchart of the manufacturing method of a scroll compressor (particularly the part related to the formation of the sliding bearing). This is an image of the SEM image of the surface of the resin-impregnated layer of the composite material after the surface of the resin-impregnated layer of the composite material has been machined. This is a diagram to explain the contact angle between a droplet and the surface of the resin-impregnated layer of the composite material, which is used to calculate the surface energy of the surface of the resin-impregnated layer of the composite material.

[0025] Hereinafter, embodiments of a refrigerant compressor, a refrigeration cycle system having this refrigerant compressor, and a method for manufacturing this refrigerant compressor will be described with reference to the drawings.

[0026] (1) Refrigeration cycle device An air conditioner 10 according to one embodiment of a refrigeration cycle device has a scroll compressor 100 and is a device that uses a vapor compression refrigeration cycle to cool or heat the air in a space to be air-conditioned in order to perform cooling and heating of the space to be air-conditioned.

[0027] Furthermore, the type of refrigeration cycle device in the claims is not limited to air conditioners. For example, the refrigeration cycle device may be a chiller device that cools water by exchanging heat between a refrigerant and water as a heat transfer medium flowing through a heat transfer medium circuit, or a hot water supply device that heats water by exchanging heat between a refrigerant and water as a heat transfer medium flowing through a heat transfer medium circuit. Alternatively, the refrigeration cycle device may be a refrigerator or freezer that cools the air inside the compartment.

[0028] The air conditioner 10 mainly comprises a refrigerant circuit 60. As shown in Figure 1, the refrigerant circuit 60 includes a scroll compressor 100, a flow path switching mechanism 20, a heat source heat exchanger 30, a utilization heat exchanger 40, and an expansion mechanism 50. In the refrigerant circuit 60, the scroll compressor 100, the flow path switching mechanism 20, the heat source heat exchanger 30, the utilization heat exchanger 40, and the expansion mechanism 50 are connected by piping.

[0029] The refrigerant circuit 60 is filled with R290 refrigerant (propane refrigerant). R290 refrigerant has the excellent characteristic of having a low global warming potential. However, R290 refrigerant is designated as CLASS 3 (highly flammable) in ISO 817:2014 (refrigerants - nomenclature and safety classification), and therefore has the characteristic of being flammable.

[0030] The scroll compressor 100 is a device that draws in low-pressure (hereinafter sometimes simply referred to as low-pressure) gaseous refrigerant in the refrigeration cycle, pressurizes it, and discharges it as high-pressure (hereinafter sometimes simply referred to as high-pressure) gaseous refrigerant in the refrigeration cycle. The scroll compressor 100 compresses R290 refrigerant. Details of the scroll compressor 100 will be described later.

[0031] The flow path switching mechanism 20 is a mechanism that switches the state of the refrigerant circuit 60 between a cooling state and a heating state. Although not limited to it, the flow path switching mechanism 20 is a four-way switching valve. When the refrigerant circuit 60 is in the cooling state, the refrigerant flows through the refrigerant circuit 60 in the following order: scroll compressor 100, flow path switching mechanism 20, heat source heat exchanger 30, expansion mechanism 50, utilization heat exchanger 40, flow path switching mechanism 20, and scroll compressor 100 (see the solid line in the flow path switching mechanism 20 in Figure 1). When the refrigerant circuit 60 is in the heating state, the refrigerant flows through the refrigerant circuit 60 in the following order: scroll compressor 100, flow path switching mechanism 20, utilization heat exchanger 40, expansion mechanism 50, heat source heat exchanger 30, flow path switching mechanism 20, and scroll compressor 100 (see the dashed line in the flow path switching mechanism 20 in Figure 1).

[0032] The heat source heat exchanger 30 is a heat exchanger that performs heat exchange between a heat source medium and a refrigerant. When the refrigerant circuit 60 is in a cooling state, the heat source heat exchanger 30 functions as a refrigerant condenser (heat radiator). When the refrigerant circuit 60 is in a heating state, the heat source heat exchanger 30 functions as a refrigerant evaporator (heat absorber).

[0033] The heat exchanger 40 is a heat exchanger that performs heat exchange between the temperature to be controlled (in this case, the air in the air-conditioned space) and the refrigerant. When the refrigerant circuit 60 is in a cooling state, the heat exchanger 40 functions as a refrigerant evaporator (heat absorber). When the refrigerant circuit 60 is in a heating state, the heat exchanger 40 functions as a refrigerant condenser (heat radiator).

[0034] The expansion mechanism 50 reduces the pressure of the high-pressure refrigerant (mainly liquid refrigerant) passing through it, converting it into a low-pressure refrigerant (a two-phase refrigerant consisting of liquid and gas). The expansion mechanism 50 is, for example, an electronic expansion valve. However, the type of expansion mechanism 50 is not limited to an electronic expansion valve; it may also be a thermostatic expansion valve with a temperature-sensing tube or a capillary tube.

[0035] The cooling and heating operations performed by the air conditioner 10 will be explained.

[0036] When the air conditioner 10 is in cooling operation, the scroll compressor 100 draws in low-pressure gaseous refrigerant, pressurizes it, and discharges it as high-pressure gaseous refrigerant. The high-pressure gaseous refrigerant discharged by the scroll compressor 100 passes through the flow path switching mechanism 20 and is supplied to the heat source heat exchanger 30, which functions as a condenser. The heat source heat exchanger 30 exchanges heat between the high-pressure gaseous refrigerant and a heat source medium (in this case, air supplied by the heat source fan 35), condensing the high-pressure gaseous refrigerant into high-pressure liquid refrigerant. The high-pressure liquid refrigerant flowing out of the heat source heat exchanger 30 passes through the expansion mechanism 50 to become low-pressure gaseous two-phase refrigerant and is supplied to the utilization heat exchanger 40, which functions as an evaporator. The utilization heat exchanger 40 exchanges heat between the air in the air-conditioned space supplied by the utilization fan 45 and the low-pressure gaseous two-phase refrigerant, evaporating the liquid refrigerant contained in the gaseous two-phase refrigerant and converting it into low-pressure gaseous refrigerant. At this time, the air in the air-conditioned space is cooled by the refrigerant. The low-pressure gaseous refrigerant flowing out of the heat exchanger 40 passes through the flow path switching mechanism 20 and is drawn back into the scroll compressor 100.

[0037] When the air conditioner 10 is operating in heating mode, the scroll compressor 100 draws in low-pressure gaseous refrigerant, pressurizes it, and discharges it as high-pressure gaseous refrigerant. The high-pressure gaseous refrigerant discharged by the scroll compressor 100 passes through the flow path switching mechanism 20 and is supplied to the utilization heat exchanger 40, which functions as a condenser. The utilization heat exchanger 40 exchanges heat between the air in the air-conditioned space supplied by the utilization fan 45 and the high-pressure gaseous refrigerant, condensing the high-pressure gaseous refrigerant into high-pressure liquid refrigerant. At this time, the air in the air-conditioned space is heated by the refrigerant. The high-pressure liquid refrigerant flowing out of the utilization heat exchanger 40 passes through the expansion mechanism 50 and becomes low-pressure gas-liquid two-phase refrigerant, which is supplied to the heat source heat exchanger 30, which functions as an evaporator. The heat source heat exchanger 30 exchanges heat between the heat source medium (in this case, the air supplied by the heat source fan 35) and the low-pressure gas-liquid two-phase refrigerant, evaporating the liquid refrigerant contained in the gas-liquid two-phase refrigerant and converting it into low-pressure gaseous refrigerant. The low-pressure gaseous refrigerant flowing out of the heat source heat exchanger 30 passes through the flow path switching mechanism 20 and is drawn back into the scroll compressor 100.

[0038] Incidentally, here, as an example of the air conditioner 10, a case where the air conditioning apparatus is a device that executes both the cooling operation and the heating operation has been described as an example. However, the air conditioning apparatus may be a device that performs only one of the cooling operation and the heating operation. In this case, the air conditioning apparatus as an example of the air conditioner 10 may not have the flow path switching mechanism 20. Further, the devices constituting the air conditioner 10 described here are merely examples, and the air conditioner 10 may have devices other than those described here.

[0039] (2) Overall Configuration of Scroll Compressor The outline of the scroll compressor 100 as an embodiment of the refrigerant compressor will be described with reference to FIG. 2 which is a schematic longitudinal sectional view of the scroll compressor 100.

[0040] Note that the scroll compressor is merely an example of the refrigerant compressor in the claims, and as long as it is a refrigerant compressor having sliding bearings such as the sliding bearings 200 and 300 described later, it may be a positive displacement refrigerant compressor other than the scroll type or a centrifugal refrigerant compressor.

[0041] Further, here, as an example, a so-called high-pressure dome type scroll compressor in which the space where the motor 170 of the casing 110 described later is disposed is at a high pressure in the refrigeration cycle will be described. However, the scroll compressor may be a so-called low-pressure dome type scroll compressor in which the space where the motor of the casing is disposed is at a low pressure in the refrigeration cycle. <00 (1) Overall Configuration of Air Conditioner 10 As shown in FIGS. 1 and 2, the air conditioner 10 mainly includes a casing 100, a compressor mechanism 120, a housing 150, a motor 170, a drive shaft 180, a lower bearing housing 190, and refrigeration machine oil O stored in the casing 110.

[0043] ​(2-1) The casing scroll compressor 100 has a vertically long cylindrical casing 110 (see Fig. 2). Note that the casing of the scroll compressor is not limited to a vertically long shape and may be a horizontally long shape. In other words, the scroll compressor is not limited to a vertical scroll compressor, and a horizontal scroll compressor in which a compression mechanism, a housing, a motor, etc. are arranged side by side in the horizontal direction (the axial direction of the drive shaft 180 extends in the horizontal direction) may be used.

[0044] The casing 110 houses various members constituting the scroll compressor 100, including a compression mechanism 120, a housing 150, a motor 170, a drive shaft 180, and a lower bearing housing 190 (see Fig. 2). The compression mechanism 120 is arranged at the upper part inside the casing 110. In the casing 110, the housing 150 is arranged below the compression mechanism 120, the motor 170 is arranged below the housing 150, and the lower bearing housing 190 is arranged below the motor 170.

[0045] An oil reservoir space 112 is formed at the bottom of the casing 110. Refrigerant oil O for lubricating various sliding parts of the scroll compressor 100 is stored in the oil reservoir space 112.

[0046] The refrigerant oil O is a polyalkylene glycol-based refrigerant oil (PAG) having an OH group at the end of its chemical structure. However, the refrigerant oil O is not limited to PAG, and may be a polyol ester-based refrigerant oil (POE) or a polyvinyl ether-based refrigerant oil (PVE) having an OH group at the end of its chemical structure.

[0047] Refrigerant oil having an end OH group has a high polarity, and R290 refrigerant (propane) has a low polarity. Therefore, the compatibility between the refrigerant oil O stored in the casing 110 and the R290 refrigerant is low. Therefore, (since the penetration of the R290 refrigerant into the refrigerant oil O does not need to be considered much), an increase in the amount of refrigerant filled in the air conditioner 10 can be suppressed.

[0048] The casing 110 is fitted with an intake pipe 114 and a discharge pipe 116 so as to connect the inside and outside of the casing 110 (see Figure 2).

[0049] The scroll compressor 100 draws in low-pressure refrigerant from the suction pipe P1 (see Figure 1) of the air conditioner 10 via the suction pipe 114, compresses the refrigerant using the compression mechanism 120, and discharges it from the discharge port 132 (see Figure 2), which will be described later, of the compression mechanism 120. The refrigerant discharged from the discharge port 132 flows into the space below the housing 150 through the fixed scroll 130 of the compression mechanism 120 and passages (not shown) formed in the housing 150. The refrigerant that has flowed into the space below the housing 150 flows out through the discharge pipe 116 to the discharge pipe P2 (see Figure 1) of the air conditioner 10.

[0050] (2-2) Compression mechanism The compression mechanism 120 mainly comprises a fixed scroll 130 and a movable scroll 140.

[0051] The fixed scroll 130 is mounted on the housing 150 and is fixed to the housing 150 by fastening means (e.g., bolts) not shown.

[0052] As shown in Figure 2, the fixed scroll 130 mainly consists of a first end plate 134, a first wrap 136, and a peripheral portion 138. The first end plate 134 is a disc-shaped member. The first wrap 136 is a wall-shaped member that protrudes from the first end plate 134 toward the movable scroll 140 (downward in Figure 2). When the fixed scroll 130 is viewed from the movable scroll 140 side, the first wrap 136 is formed in a spiral shape (involute shape) from near the center of the first end plate 134 toward the outer circumference. The peripheral portion 138 is a thick-walled cylindrical member that protrudes from the first end plate 134 toward the movable scroll 140 side. The peripheral portion 138 is arranged to surround the first wrap 136.

[0053] As shown in Figure 2, the movable scroll 140 mainly consists of a second end plate 142, a second wrap 144, and a boss portion 146. The second end plate 142 is a disc-shaped member, while the second wrap 144 is a wall-shaped member that protrudes from the second end plate 142 toward the fixed scroll 130 (upward in Figure 2). When the movable scroll 140 is viewed from the fixed scroll 130 side, the second wrap 144 is formed in a spiral shape (involute shape) from near the center of the second end plate 142 toward the outer circumference.

[0054] The boss portion 146 of the movable scroll 140 is located within a crank chamber 153, which will be described later, and is formed by the housing 150. The boss portion 146 is cylindrical in shape. The boss portion 146 extends from the second end plate 142 so as to protrude toward the motor 170 (downward in Figure 2). The upper part of the cylindrical boss portion 146 is closed by the second end plate 142. A sliding bearing 148 is located in the hollow portion of the boss portion 146. The eccentric portion 184 (pin shaft) of the drive shaft 180, which will be described later, is inserted into the hollow portion of the boss portion 146 (see Figure 2). The sliding bearing 148 is a sliding bearing that slidably supports the eccentric portion 184 of the drive shaft 180. Since the drive shaft 180 is connected to the rotor 174 of the motor 170, which will be described later, when the motor 170 is operated and the rotor 174 rotates, the movable scroll 140 rotates. Furthermore, the movable scroll 140, which is rotated by the motor 170, does not rotate on its own axis but revolves around the fixed scroll 130 due to the action of an Oldham coupling (not shown).

[0055] The fixed scroll 130 and the movable scroll 140 are assembled with the side of the first end plate 134 facing the movable scroll 140 (bottom surface in Figure 2) and the side of the second end plate 142 facing the fixed scroll 130 (top surface in Figure 2) facing each other. As a result, a compression chamber Sc is formed, surrounded by the first end plate 134, the second end plate 142, the first wrap 136, and the second wrap 144 (see Figure 2).

[0056] As the movable scroll 140 rotates relative to the fixed scroll 130, low-pressure refrigerant flows from the suction pipe 114 into the compression chamber Sc of the compression mechanism 120. As the refrigerant moves towards the central compression chamber Sc, it is compressed and its pressure increases. The high-pressure refrigerant compressed by the compression mechanism 120 is discharged from the discharge port 132 formed approximately in the center of the first end plate 134 and flows into a refrigerant passage (not shown) formed across the fixed scroll 130 and the main body 152 of the housing 150, which will be described later.

[0057] (2-3) Housing The housing 150 supports the fixed scroll 130 and the movable scroll 140. The housing 150 also pivotally supports the drive shaft 180.

[0058] As shown in Figure 2, the housing 150 mainly includes a main body 152 and an upper bearing housing 154.

[0059] The main body portion 152 is a cylindrical member fixed to the inner surface of the casing 110. The fixed scroll 130 is positioned such that its peripheral edge 138 contacts the main body portion 152 of the housing 150, and is fixed to the housing 150 by fixing members (e.g., bolts) not shown. The main body portion 152 supports the fixed scroll 130 which is fixed to the main body portion 152. The main body portion 152 also supports the movable scroll 140 which is positioned between the fixed scroll 130 and the main body portion 152 of the housing 150. Specifically, the main body portion 152 supports the movable scroll 140 from below via an Oldham joint (not shown) located above the housing 150.

[0060] As shown in Figure 2, the main body 152 has a first recess 152a that is recessed in the center. The first recess 152a surrounds the side surface of the crank chamber 153 where the boss portion 146 of the movable scroll 140 is located.

[0061] During steady-state operation of the scroll compressor 100 (when the operation of the scroll compressor 100 is stable), the pressure in the crank chamber 153 becomes the high pressure in the refrigeration cycle. As a result, during steady-state operation of the scroll compressor 100, the second end plate 142 facing the crank chamber 153 is pushed toward the fixed scroll 130 by the pressure.

[0062] The upper bearing housing 154 is formed in a cylindrical shape. Inside the cylindrical upper bearing housing 154, a sliding bearing 200 is provided to rotatably support the drive shaft 180. A detailed explanation of the sliding bearing 200 will be given later.

[0063] (2-4) The motor 170 is a drive mechanism that rotates the movable scroll 140 to drive the compression mechanism 120.

[0064] The motor 170 has an annular stator 172 fixed to the inner surface of the casing 110 and a rotor 174 positioned inside the stator 172 (see Figure 2).

[0065] The rotor 174 is housed inside the stator 172, with a small gap (air gap) between it and the stator 172, allowing it to rotate freely. The rotor 174 is a cylindrical member with a drive shaft 180 inserted through its interior. The motor 170 rotates the rotor 174, which in turn rotates the drive shaft 180, thereby driving the movable scroll 140 and causing the movable scroll 140 to orbit the fixed scroll 130.

[0066] (2-5) Drive shaft The drive shaft 180 connects the rotor 174 of the motor 170 and the movable scroll 140 of the compression mechanism 120. The drive shaft 180 transmits the driving force of the motor 170 to the movable scroll 140 of the compression mechanism 120.

[0067] The drive shaft 180 mainly consists of a main shaft 182 and an eccentric portion 184 (see Figure 2).

[0068] The main shaft 182 extends from the oil reservoir space 112 to the crankcase 153 in the direction of the rotation axis of the drive shaft 180. The main shaft 182 is rotatably supported by the sliding bearing 200 of the upper bearing housing 154 and the sliding bearing 300 of the lower bearing housing 190, which will be described later. The main shaft 182 is also inserted into the rotor 174 of the motor 170 between the upper bearing housing 154 and the lower bearing housing 190 of the housing 150, and is connected to the rotor 174. The central axis of the main shaft 182 coincides with the rotation axis of the drive shaft 180.

[0069] The eccentric portion 184 is located at the end of the main shaft 182. The central axis of the eccentric portion 184 is eccentric with respect to the rotation axis of the drive shaft 180. The eccentric portion 184 is inserted into the boss portion 146 of the movable scroll 140 and is rotatably supported by a sliding bearing 148 located inside the boss portion 146.

[0070] An oil passage 186 is formed inside the drive shaft 180. The oil passage 186 has a main path 186a and a branch path (not shown). The main path 186a extends along the axial direction of the drive shaft 180 from the end of the drive shaft 180 on the oil reservoir space 112 side to the end of the drive shaft 180 on the boss portion 146 side. The branch path extends from the main path 186a in a direction intersecting the axial direction of the drive shaft 180. Oil from the oil reservoir space 112 is pumped up by a pump (not shown) provided at the lower end of the drive shaft 180, passes through the oil passage 186, and is finally supplied to the sliding parts between the drive shaft 180 and the sliding bearing 148, the sliding parts between the drive shaft 180 and the sliding bearing 200, the sliding parts between the drive shaft 180 and the sliding bearing 300, and the sliding parts of the compression mechanism 120, etc.

[0071] (2-6) Lower Housing The lower bearing housing 190 mainly includes a lower bearing section 192 and a plurality of arms 194, as shown in Figure 2. The lower bearing housing 190 pivotally supports the drive shaft 180.

[0072] The lower bearing section 192 includes a sliding bearing 300 that rotatably supports the drive shaft 180. The sliding bearing 300 will be described later.

[0073] The arms 194 support the lower bearing section 192. The arms 194 are rod-shaped members. Each arm 194 extends from the lower bearing section 192 toward the casing 110 and is fixed to the inner surface of the casing 110.

[0074] (3) The sliding bearings 200 and 300 that support the sliding bearing drive shaft 180 will be described in detail.

[0075] The sliding bearings 200 and 300 are cylindrical members. Each of the sliding bearings 200 and 300 may be a single member, or multiple members may be combined to form a cylindrical shape (for example, a pair of semi-cylindrical sliding bearings). Since the sliding bearings 200 and 300 are similar members, the explanation of the sliding bearing will use the sliding bearing 200 as an example, and the explanation of the sliding bearing 300 will be omitted.

[0076] The sliding bearing 200 has a composite material CM that includes a backing plate 210 and a resin-impregnated layer 220, as shown in Figure 3B, which is an enlarged view of a part of the cross-section obtained by cutting the cylindrical sliding bearing 200 in a direction perpendicular to the axial direction of the cylinder. In other words, the sliding bearing 200 is manufactured from a composite material CM having a backing plate 210 and a resin-impregnated layer 220. Since the sliding bearing 200 is cylindrical, the actual cross-sectional shape of the sliding bearing 200 is arc-shaped, but in Figure 3B, the cross-section of the sliding bearing 200 is drawn as a straight line.

[0077] In the resin-impregnated layer 220 of the sliding bearing 200, a porous metal M is impregnated with a resin P containing a fluororesin (see Figure 3B). The resin-impregnated layer 220 is not limited to a specific material, but for example, metal M such as iron-based, copper-iron-based, copper-based, or stainless steel-based metals can be used. In this embodiment, the porous metal M used in the resin-impregnated layer 220 is bronze. The resin P impregnated in the resin-impregnated layer 220 contains PTFE (polytetrafluoroethylene) as a fluororesin. The resin P also contains fillers and the like.

[0078] The composite material CM used in the sliding bearing 200 is formed, for example, by sintering bronze powder into a porous structure onto a backing metal 210 such as steel, and then impregnating it with a resin containing PTFE.

[0079] The sliding bearing 200 is formed from a base material (a component in which a layer of porous metal impregnated with a resin containing PTFE is laminated onto a backing plate 210) by, for example, the following:

[0080] Referring to the schematic flowchart of the manufacturing method of the scroll compressor 100 (particularly the part relating to the formation of the sliding bearing 200) shown in Figure 5, the details of the formation of the sliding bearing 200 of the scroll compressor 100 will be explained. Note that the details of the formation of the sliding bearing 200 described below are merely one example of the process for forming the sliding bearing 200, and other processes may be included, for example.

[0081] First, a base material of appropriate size is processed into a cylindrical shape in the molding process (process A1). In other words, in process A1, the composite material CM that will become the sliding bearing 200 is processed into a cylindrical shape. When processed into a cylindrical shape, the resin-impregnated layer 220 (before the cutting process described later) is placed on the inner circumference side and the backing plate 210 is placed on the outer circumference side of the base material. Although not limited to this, in process A1, for example, a flat base material is processed into a cylindrical shape in the molding process. Specifically, a flat base material is processed into a cylindrical shape by, for example, roll bending. Note that the shape of the base material before being processed into a cylindrical shape is not limited to a flat shape and may be other shapes.

[0082] Next, in step A2, the resin-impregnated layer 220 that constitutes the sliding surface 222 (the surface that contacts the main shaft 182 of the drive shaft 180 when used as a sliding bearing 200) of the cylindrically processed base material is cut, and the metal exposure rate of the cut surface (sliding surface 222) is set to a predetermined metal exposure rate. The reason for performing step A2 will be explained.

[0083] In the base material of the sliding bearing 200, as shown in Figure 3A, the surface of the resin-impregnated layer 220 (the inner circumferential surface of the cylindrical base material located on the opposite side from the backing plate 210) is mostly covered with resin P, and the metal M is not exposed. Since resin P has low wear resistance, if the sliding bearing were used in this state, the surface of the sliding bearing supporting the drive shaft 180 would wear down, and even if the dimensions of the sliding bearing were appropriate when the scroll compressor 100 was first put into use, the dimensions of the sliding bearing may change during use and may no longer be appropriate.

[0084] Therefore, in the manufacturing of the sliding bearing 200 of this embodiment, in step A2, the surface of the resin-impregnated layer 220 is cut to set the metal exposure rate of the cut surface (sliding surface 222) to a predetermined metal exposure rate ER. By setting the metal exposure rate of the sliding surface 222 to a predetermined metal exposure rate ER, the wear resistance of the sliding surface 222 is improved, and dimensional changes of the sliding bearing 200 due to aging deterioration can be suppressed.

[0085] In fact, when a resin-impregnated layer 220, which was made by impregnating porous bronze with a resin containing a fluororesin, was cut, a positive correlation was obtained between the amount of material removed and the percentage of exposed metal. The correlation between the amount of material removed and the percentage of exposed metal can be appropriately determined for the base material actually used.

[0086] The predetermined metal exposure ratio ER is determined by considering not only wear resistance but also the surface energy value. This will be explained in detail.

[0087] The surface energy is N / m (or J / m). ２ It is a physical quantity expressed in units of ). The surface energy value of the surface (sliding surface 222) of the sliding bearing 200 affects the adhesion between the surface (sliding surface 222) of the sliding bearing 200 and the refrigerant oil O. When the surface energy is high, the adhesion between the surface of the sliding bearing 200 and the refrigerant oil O increases, and the refrigerant oil O tends to remain between the surface of the sliding bearing 200 and the surface of the drive shaft 180. On the other hand, when the surface energy is low, the adhesion between the surface of the sliding bearing 200 and the refrigerant oil O decreases, and the refrigerant oil O tends to remain between the surface of the sliding bearing 200 and the surface of the drive shaft 180.

[0088] In the scroll compressor 100 of this embodiment, as described above, PAG, POE, or PVE having an OH group at the end of its chemical structure is used as the refrigerant oil O. Therefore, the compatibility between the R290 refrigerant and the refrigerant oil O is low, and a high-viscosity refrigerant oil O is used to lubricate the sliding bearing 200. Under these conditions, if the surface energy value of the surface (sliding surface 222) of the sliding bearing 200 is high, the refrigerant oil O tends to remain between the surface of the sliding bearing 200 and the surface of the drive shaft 180. As a result, the temperature of the sliding part between the sliding bearing 200 and the drive shaft 180 and the components arranged around it may rise beyond the appropriate temperature range, potentially reducing the reliability of the scroll compressor 100. For this reason, it is preferable that the surface energy value of the surface (sliding surface 222) of the sliding bearing 200 be low.

[0089] Generally, the surface energy of metals is greater than that of resins.

[0090] For example, the surface energy of copper is around 1100 mN / m. The surface energies of other metals are also generally several hundred mN / m or more. For instance, the surface energy of stainless steel is around 700 to 1100 mN / m. In contrast, the surface energy of PTFE is around 18 mN / m, significantly lower than that of other metals.

[0091] Therefore, from the viewpoint of wear resistance, a large predetermined metal exposure ratio ER is preferable, while from the viewpoint of suppressing the surface energy value of the sliding surface 222 of the plain bearing 200, a small predetermined metal exposure ratio ER is preferable.

[0092] In the sliding bearing 200, a predetermined metal exposure ratio ER is determined such that the surface energy on the surface of the resin-impregnated layer 220 is less than 40 mN / m, from the viewpoint of achieving both wear resistance and suppression of temperature rise in the sliding portion between the sliding bearing 200 and the drive shaft 180.

[0093] Furthermore, from the viewpoint of suppressing temperature rise in the sliding portion between the sliding bearing 200 and the drive shaft 180, it is more preferable to determine a predetermined metal exposure rate ER such that the surface energy on the surface of the resin-impregnated layer 220 is less than 35 mN / m. From the viewpoint of suppressing temperature rise in the sliding portion between the sliding bearing 200 and the drive shaft 180, it is even more preferable to determine a predetermined metal exposure rate ER such that the surface energy on the surface of the resin-impregnated layer 220 is less than 30 mN / m.

[0094] Figure 4 is a graph showing the measured surface energy [mN / m] values ​​when the metal exposure rate [%] of the surface of the sliding bearing 200 is changed (the method for calculating surface energy used in this embodiment will be described later).

[0095] From the perspective of the surface energy value obtained from this graph and the wear resistance of the surface of the sliding bearing 200, the predetermined metal exposure ratio ER is determined to be in the range of 5% to 80%.

[0096] Preferably, the predetermined metal exposure rate ER is determined in the range of 20% to 70%. More preferably, the predetermined metal exposure rate ER is determined in the range of 20% to 60%. Even more preferably, the predetermined metal exposure rate ER is determined in the range of 30% to 60%. Even more preferably, the predetermined metal exposure rate ER is determined in the range of 30% to 50%.

[0097] By setting the predetermined metal exposure ratio ER to a value within this range, a scroll compressor 100 is realized that has excellent wear resistance and can also suppress temperature rise in the sliding portion between the sliding bearing 200 and the drive shaft 180.

[0098] Furthermore, even under conditions where the metal exposure rate is relatively high and the surface energy of the metal is likely to have a relatively large influence on the surface energy of the sliding bearing 200, the surface energy value of the sliding bearing 200 remains relatively low, as shown in Figure 4. The following reasons can be considered for this.

[0099] In this embodiment, the metal exposure rate on the surface of the sliding bearing 200 is measured by obtaining a scanning electron microscope image (SEM image) of the surface (sliding surface 222) of the sliding bearing 200 at a magnification of 200x, dividing this SEM image into parts where metal M is present and parts where resin P is present by image processing (binarization), and measuring the ratio of pixels representing the parts where metal M is present to the total number of pixels in the image.

[0100] When examining actual SEM images, the regions containing metal M and the regions containing resin P are not clearly separated. Rather, as schematically shown in Figure 6, regions containing metal M (shown as hatched areas in Figure 6) also contain regions containing resin P (shown as hatched dots in Figure 6).

[0101] For example, although it falls outside the above range of metal exposure rate ER (5% to 80%), in an actual SEM image of the surface of the resin-impregnated layer 220 of composite material CM, where the metal exposure rate was measured to be 86% (14% exposure rate of resin P), if we assume that the regions where metal M is mainly present (as explained in Figure 6, the regions R1, R2, R3, enclosed by dashed lines and marked with hatched lines) are all occupied by metal M, the metal exposure rate was calculated to be 88% (12% exposure rate of resin P). In other words, on the surface of the resin-impregnated layer 220 of composite material CM with a metal exposure rate of 86%, it can be seen that 14% (= (14% - 12%) / 14%) of the total exposed resin P (resin P occupying 14% of the surface) is located on the regions where metal M is mainly present. In this way, by having 2% ((14%-12%) / 88%) or more of resin P in the region where metal M is mainly present, the increase in surface energy in response to an increase in metal exposure can be suppressed.

[0102] Thus, it is presumed that the presence of resin P scattered throughout the region where metal M is primarily present suppresses the increase in surface energy in response to an increase in metal exposure.

[0103] Furthermore, the reason why resin P is scattered in the area where metal M is mainly present is presumed to be due to "transfer." Here, "transfer" means that material that has been worn away due to abrasion adheres to other locations. In the case of the resin-impregnated layer 220 of the composite material CM, it is presumed that during the cutting process in step A2 described above, and also due to the sliding between the drive shaft 180 and the resin-impregnated layer 220, resin P transfers onto the metal M, resulting in a state where resin P is thinly spread on the surface of metal M (a state where resin P is scattered on the surface of metal M).

[0104] (4) Method for calculating surface energy The method for calculating surface energy used in the above explanation will now be explained.

[0105] To begin with, surface energy is a value calculated by measuring the contact angle θ (which will be explained later) of each droplet when two or more solutions are dropped onto the surface of the object whose surface energy is being calculated. Here, we are calculating the surface energy using two types of solutions.

[0106] Because the method for calculating surface energy is as described above, it is difficult to calculate the surface energy using the cylindrical sliding bearing 200 itself (because the sliding surface 222 of the cylindrical sliding bearing 200 is a curved surface).

[0107] Therefore, the surface energy calculated by the method shown below (the surface energy of the sliding surface 222 of the sliding bearing 200) is not a value calculated using the actual sliding surface 222 of the cylindrical sliding bearing 200, but rather a value calculated using the plane of a flat composite material CM (the same composite material CM used to operate the sliding bearing 200) with the same metal exposure ratio as the sliding surface 222 of the sliding bearing 200. However, for the sake of simplicity, the surface energy calculated by the method shown below will be referred to here as the surface energy of the sliding surface 222 of the sliding bearing 200.

[0108] In this embodiment, the surface energy is calculated as follows.

[0109] As shown in Figure 7, assume that a droplet L is placed on a plane 400 (the surface of the resin-impregnated layer 220 of the composite material CM) of the object whose surface energy is to be calculated. At this time, the droplet L forms a predetermined contact angle θ with the plane 400.

[0110] In this state, the three surface tensions (γ) acting on point X in Figure 7 s : Surface tension of a solid, γ l : Surface tension of liquid, γ sl The interfacial tension between the solid and liquid is in equilibrium. This relationship is expressed by the following equation 1 (Young's equation). Formula 1

[0111]

[0112] Furthermore, γ is the interfacial tension between solid and liquid. sl Regarding this, equation 2, known as the extended Fowkes formula, is known. Formula 2

[0113]

[0114] Then, by combining equation 1 and equation 2, we obtain the following equation 3 (Owens's equation). Formula 3

[0115]

[0116] Here, the sign in equation 3 means the following values:

[0117]

[0118] In this embodiment, surface tension γ l Ingredients We measure θ using two known types of liquids and substitute these values ​​into Equation 3, By substituting θ into the two equations and solving them simultaneously, the surface tension γ of the adherend surface (surface of the resin-impregnated layer 220) can be determined. s and its components They are looking for...

[0119] The solution includes, for example, and, And can be used. For each of these solutions, the contact angle θ can be measured and substituted into equation 3, and by solving the two equations simultaneously, the surface of the adherend (the surface of the resin-impregnated layer 220) can be determined. and the sum of them is surface tension. The surface tension γ of the adherend surface (surface of the resin-impregnated layer 220) obtained here can be determined. s This value represents the surface energy of the adherend surface (the surface of the resin-impregnated layer 220).

[0120] Furthermore, in calculating the surface energy in the correlation graph between metal exposure rate and surface energy shown in Figure 4, the contact angle θ was measured using the contact angle measurement method (static droplet method) described in JIS R 3257:1999, as follows.

[0121] Furthermore, in calculating the surface energy in the correlation graph between metal exposure rate and surface energy in Figure 4, the contact angle θ was measured using a solution other than water and methylene iodide. and, and are used.

[0122] The operator dropped 2 μl of each solution onto the surface of a resin-impregnated layer 220, whose metal exposure rate was known (measured from a 200x magnification SEM image). After a waiting time of 1000 ms, the contact angle was measured using a DropMaster 702 (contact angle meter) manufactured by Kyowa Interface Science Co., Ltd. The contact angle was measured five times for each solution. The maximum and minimum values ​​obtained from the five measurements were excluded as outliers, and the average of the remaining values ​​was taken to obtain the contact angle θ for each solution. The operator then used equation 3 (Owens' equation) in the method described above to calculate the surface energy value of the adherend surface (surface of the resin-impregnated layer 220) shown in Figure 4.

[0123] (5) Features Here, with respect to sliding bearings, the features of the scroll compressor 100 and the air conditioner 10 will be explained using the sliding bearing 200 as an example, but the sliding bearing 200 can be read as a sliding bearing 300.

[0124] (5-1) The scroll compressor 100 comprises a compression mechanism 120, a drive shaft 180, a cylindrical sliding bearing 200, a casing 110, and refrigerant oil O. The compression mechanism 120 compresses R290 refrigerant (propane refrigerant). The drive shaft 180 transmits power to the compression mechanism 120. The sliding bearing 200 supports the drive shaft 180. The casing 110 houses the compression mechanism 120, the drive shaft 180, and the sliding bearing 200. The refrigerant oil O is stored in the casing 110. The refrigerant oil O is PAG (polyalkylene glycol), POE (polyol ester), or PVE (polyvinyl ether), which have OH groups at the ends of their chemical structure. The sliding bearing 200 has a composite material CM which includes a resin-impregnated layer 220 in which a resin P containing PTFE is impregnated into a porous metal M. The sliding surface 222 of the plain bearing 200 is composed of a resin-impregnated layer 220, with metal exposed at a predetermined metal exposure rate ER. At the predetermined metal exposure rate ER, the surface energy of the resin-impregnated layer 220 of the composite material CM is less than 40 mN / m.

[0125] When the surface energy of the sliding surface 222 of the sliding bearing 200 is high, the refrigerant oil O tends to remain in the sliding portion between the sliding bearing 200 and the drive shaft 180.

[0126] In contrast, the scroll compressor 100 uses a sliding bearing 200 that has a low surface energy on the sliding surface 222 of the sliding bearing 200. This allows for the rapid discharge of refrigerant oil O from the sliding part between the sliding bearing 200 and the drive shaft 180, thereby suppressing the temperature rise of the components constituting the sliding part between the sliding bearing 200 and the drive shaft 180.

[0127] Furthermore, it is preferable that the surface energy at the surface of the resin-impregnated layer 220 of the composite material CM at a predetermined metal exposure rate ER is less than 35 mN / m. It is even more preferable that the surface energy at the surface of the resin-impregnated layer 220 of the composite material CM at a predetermined metal exposure rate ER is less than 30 mN / m.

[0128] In this way, by using a sliding bearing 200 in which the surface energy of the sliding surface 222 of the sliding bearing 200 is kept low, the refrigerant oil O can be quickly discharged from the sliding part between the sliding bearing 200 and the drive shaft 180, thereby suppressing the temperature rise of the components constituting the sliding part between the sliding bearing 200 and the drive shaft 180.

[0129] (5-2) In the scroll compressor 100, the predetermined metal exposure rate ER is in the range of 5% to 80%.

[0130] Here, ensuring a minimum metal exposure rate of 5% makes it easier to ensure the wear resistance of the sliding bearing 200. On the other hand, by limiting the metal exposure rate to 80% or less, the surface energy of the sliding bearing 200 can be suppressed to less than 40 mN / m (see Figure 4).

[0131] The predetermined metal exposure rate ER is preferably in the range of 20% to 70%, more preferably in the range of 20% to 60%, even more preferably in the range of 30% to 60%, and even more preferably in the range of 30% to 50%.

[0132] By setting the metal exposure rate within the range described above, it is possible to ensure relatively high wear resistance of the sliding bearing 200 while keeping the surface energy of the sliding surface 222 of the sliding bearing 200 relatively low.

[0133] (5-3) The manufacturing method of the scroll compressor 100 of this embodiment comprises the steps of processing a composite material CM that will become a sliding bearing 200 into a cylindrical shape, and cutting the resin-impregnated layer 220 that constitutes the sliding surface 222 of the sliding bearing 200, and setting the metal exposure rate of the cut surface (sliding surface 222) to a predetermined metal exposure rate ER.

[0134] Here, by setting the sliding surface 222 of the sliding bearing 200 to a predetermined metal exposure ratio ER, a sliding bearing 200 can be realized in which the surface energy of the sliding surface is suppressed to less than 40 mN / m. In the scroll compressor 100, the refrigerant oil O can be quickly discharged from the sliding part between the sliding bearing 200 and the drive shaft 180, thereby suppressing the temperature rise of the components constituting the sliding part between the sliding bearing 200 and the drive shaft 180.

[0135] Furthermore, by machining the sliding surface 222 of the sliding bearing 200 to a predetermined metal exposure ratio ER, even if the metal exposure ratio is increased to improve the wear resistance of the sliding surface 222 of the sliding bearing 200, the increase in the surface energy of the sliding surface 222 can be relatively suppressed. This is presumed to be because, as mentioned above, the transfer of resin P results in the resin P being scattered on the surface of the metal M of the sliding surface 222 of the resin-impregnated layer 220.

[0136] In addition, in the manufacturing of the scroll compressor 100, the general manufacturing process for scroll compressors can be applied to parts other than the manufacturing of the sliding bearings 200.

[0137] (6) Modifications The following describes modifications of the above embodiments. The following modifications may be combined as appropriate, as long as they do not contradict each other.

[0138] (6-1) Modified Example A In the above embodiment, the sliding bearings 200 and 300 have a composite material CM which includes a resin-impregnated layer in which a resin containing PTFE is impregnated into a porous metal, and the sliding surface of the sliding bearings 200 and 300 is made of the resin-impregnated layer, and the metal is exposed on the sliding surface at a predetermined metal exposure rate ER.

[0139] However, the invention is not limited to this, and the sliding bearing 148 positioned on the boss portion 146 of the movable scroll 140 also has a composite material CM including a resin-impregnated layer in which a resin containing PTFE is impregnated into a porous metal, similar to the sliding bearings 200 and 300, and the sliding surface of the sliding bearing 148 is made of the resin-impregnated layer, and the metal may be exposed on the sliding surface at a predetermined metal exposure rate ER.

[0140] (6-2) Modification B As described above, the refrigerant compressor in the claims is not limited to a scroll compressor, as long as it is a refrigerant compressor having a sliding bearing as described in the above embodiment. Specifically, for example, the refrigerant compressor in the claims may be a rotary compressor.

[0141] <Note> Although embodiments and modifications of this disclosure have been described above, it should be understood that various changes in form and details are possible without departing from the spirit and scope of this disclosure as described in the claims.

[0142] 10 Air conditioner (refrigeration cycle device) 100 Scroll compressor (refrigerant compressor) 110 Casing 120 Compression mechanism 180 Drive shaft 200 Sliding bearing (sliding bearing) 300 Sliding bearing (sliding bearing) O Refrigeration oil

[0143] International Publication No. 2017 / 72867

Claims

1. A refrigerant compressor comprising: a compression mechanism (120) for compressing R290 refrigerant; a drive shaft (180) for transmitting power to the compression mechanism; a cylindrical sliding bearing (200) for supporting the drive shaft; a casing (110) for housing the compression mechanism, the drive shaft, and the sliding bearing; and refrigerant oil (O) stored in the casing, wherein the refrigerant oil is PAG, POE, or PVE having OH groups at the ends of its chemical structure; the sliding bearing has a composite material including a resin-impregnated layer in which a resin containing PTFE is impregnated into a porous metal; the sliding surface (222) of the sliding bearing is composed of the resin-impregnated layer, with the metal exposed at a predetermined metal exposure rate; and the surface energy at the surface of the resin-impregnated layer of the composite material at the predetermined metal exposure rate is less than 40 mN / m.

2. The refrigerant compressor according to claim 1, wherein the predetermined metal exposure rate is in the range of 5% to 80%.

3. The refrigerant compressor according to claim 2, wherein the predetermined metal exposure rate is in the range of 30% to 60%.

4. The refrigerant compressor according to any one of claims 1 to 3, wherein the surface energy is less than 35 mN / m.

5. The refrigerant compressor according to claim 4, wherein the surface energy is less than 30 mN / m.

6. A refrigeration cycle device (10) comprising a refrigerant compressor according to any one of claims 1 to 5.

7. A method for manufacturing a refrigerant compressor according to any one of claims 1 to 5, comprising the steps of: processing the composite material that will become the sliding bearing into a cylindrical shape; and cutting the resin-impregnated layer that constitutes the sliding surface of the sliding bearing, and setting the metal exposure rate of the cut surface to the predetermined metal exposure rate.

Images