JP2008088847A - Scroll type compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a scroll type compressor of easy control and low cost having a thrust bearing formed out of bearing material in which wear quantity of bearing slide surface is a little and performance does not practically drop even under use in a boundary or mixed lubrication zone. <P>SOLUTION: The scroll type compressor 11 is provided with a fixed scroll 38 and a movable scroll 32 compressing fluid by rotated in relation to the fixed scroll 38 by a rotary shaft 21, and includes the thrust bearing 53 bearing axial force acting on the scroll 32. The bearing 53 includes one slide surface 100 and another slide surface 101 opposing to the slide surface 100. One slide surface 100 or another slide surface 101 is fixed on the scroll 32. The slide surfaces 100, 101 are formed out of steel material, and residual austenite quantity near surfaces of both of the slide surfaces 100, 101 is 5 vol.% or higher. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a scroll compressor.

  In general, a scroll compressor has a fixed scroll fixed to a housing, and a movable scroll that is disposed opposite to the fixed scroll and revolves with respect to the fixed scroll by a rotation shaft. The fixed scroll and the movable scroll. And compresses the fluid. The movable scroll receives a force in the thrust direction due to a pressure difference between the pressure on the back surface of the movable scroll and the pressure of the fluid to be compressed, and the force in the thrust direction is supported by a thrust bearing.

  Since the orbiting scroll revolves, the sliding speed when the thrust bearing is used in a scroll compressor is smaller than the sliding speed when the thrust bearing is used in a device that rotates. For this reason, it is difficult to form a lubricating oil film on the sliding surface, and seizure or the like is likely to occur.

  In particular, in a compressor used in a refrigeration cycle using a carbon dioxide refrigerant, since the pressure of the refrigerant to be compressed is high, the force in the thrust direction also increases, and the formation of an oil film on the sliding surface of the thrust bearing is a more important issue. Become.

  Some scroll compressors using carbon dioxide refrigerant for automobiles have a thrust bearing with a pair of sliding surfaces made of plain flat plates, and an excessive load is generated on the sliding surfaces. There is a problem that the oil film between the sliding surfaces is broken and seizure occurs.

  2. Description of the Related Art Conventionally, scroll-type compressors having various devices on the sliding surface have been proposed.

  For example, in a scroll compressor having a thrust bearing composed of a sliding surface of a movable scroll and a fixed sliding surface, a pressure is applied to the back surface of the shaft of the movable school to reduce the load applied to the sliding surface. A pressure mechanism has been proposed, but this mechanism is complicated to control and leads to an increase in cost.

  Further, in Patent Document 1, in a scroll compressor in which a plurality of tapered land bearing mechanisms are formed on a thrust bearing surface that supports a movable scroll, the tapered land bearing mechanism includes a tapered portion inclined in a turning direction and a constant portion. It is disclosed that a large number of land portions are formed in a circular shape.

  The scroll type compressor described in Patent Document 1 is intended to generate an oil film due to the wedge effect on the sliding surface of the thrust bearing. There is no description about the material and heat treatment of the bearing part to ensure the wear resistance.

Japanese Patent Laid-Open No. 8-319959

  The present invention aims to solve the above-mentioned problems, is easy to control, is low in cost, and even when a thrust bearing is used in a boundary or mixed lubrication region, the amount of wear on the bearing sliding surface is small, It is an object of the present invention to provide a scroll compressor formed of a bearing material that does not substantially cause a performance degradation.

  In order to solve the above-mentioned problem, the invention described in claim 1 includes a fixed scroll (38) and a movable scroll (32) that compresses fluid by rotating with respect to the fixed scroll (38) by a rotating shaft (21). ) Having a thrust bearing (53) that receives the axial force received by the movable scroll (32), and the thrust bearing (53) has one sliding surface (100). ) And the other sliding surface (101) facing the one sliding surface (100), the one sliding surface (100) or the other sliding surface (101) Fixed to the movable scroll (32), each of the one sliding surface (100) and the other sliding surface (101) is made of steel, and both sliding surfaces (100, 101). Residual oxygen near the surface Wherein the austenite amount is 5 vol% or more.

  Thereby, since the wear resistance of the surface in each of a pair of sliding surfaces (100, 101) is improved, even if a thrust bearing (53) is used in a boundary or a mixed lubrication area, the sliding surfaces (100, 101). ) Wear amount is small, and the scroll compressor does not substantially deteriorate in performance. Further, according to this scroll compressor, the control is not complicated and the cost is not high.

  In the present specification, “substantially no performance degradation” means that even if the sliding surfaces (100, 101) are worn, the amount of wear is slight. It means no effect.

  The invention according to claim 2 is the invention according to claim 1, wherein the thrust bearing (53) has a plurality of floating island-shaped pressure receiving portions (83) surrounded by the groove (85) and independent of each other. The sliding surface (100) of the first sliding surface (100) and the portion facing the pressure receiving portion (83) of the one sliding surface (100) have the other substantially flat sliding surface (101), The pressure receiving portion (83) has a sag portion (83b) formed at the peripheral edge of the pressure receiving portion (83) and a flat portion (83a) inside the sag portion (83b). The standard deviation σ1 of the surface roughness on the sliding surface (100) and the standard deviation σ2 of the surface roughness on the other sliding surface (101) are each 0.08 μm or less.

  As a result, an oil film is easily formed on the floating island-shaped pressure receiving portion (83) surrounded by the groove (85), and it is easy to form a fluid lubrication state, and the pair of sliding surfaces (100, 101). Since the surface roughness of each is small, the wear amount of the sliding surface (100, 101) is small even when used in the boundary or the mixed lubrication region, and the anti-seizure property is enhanced, and the scroll type compressor is deteriorated in performance. Substantially does not occur.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, a fluid containing lubricating oil is supplied to the sliding surfaces (100, 101) of the thrust bearing (53), and the other sliding surface is provided. The sliding speed of the pressure receiving part (83) with respect to (101) becomes 0.5 m / sec or more, and a load with an average surface pressure of 0.5 to 20 MPa is applied to the pressure receiving part (83). It is used in a state where the viscosity is 0.1 to 10 cst.

  Thereby, the fluid lubrication state of the thrust bearing (53) is ensured, and wear generated on the sliding surface (100, 101) due to the boundary or mixed lubrication at the time of start-up or liquid back is reduced.

  The invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein each of the one sliding surface (100) and the other sliding surface (101) has a retained austenite amount. Is characterized by extending over a depth of 10 micrometers or more from the surface.

  Thus, each of the pair of sliding surfaces (100, 101) of the thrust bearing (53) has a portion with improved wear resistance in a region from the surface to a predetermined depth, so that the thrust bearing (53 ) Is used in the boundary or mixed lubrication region, and even if the sliding surfaces (100, 101) wear, the function of the thrust bearing (53) continues to be reliably maintained for a predetermined period.

  The invention according to claim 5 is a scroll comprising a fixed scroll (38) and a movable scroll (32) that compresses fluid by turning with respect to the fixed scroll (38) by a rotating shaft (21). The type compressor has a thrust bearing (53) that receives the axial force received by the movable scroll (32), and the thrust bearing (53) includes one sliding surface (100) and the one sliding surface. The other sliding surface (101) facing the moving surface (100), and the one sliding surface (100) or the other sliding surface (101) is fixed to the movable scroll (32). The hardness of the other sliding surface (101) is higher than that of the one sliding surface (100), and the difference in Vickers hardness between both sliding surfaces (100, 101) is 500 HV or more. It is characterized by.

  Thereby, since the wear resistance of the surface in each of a pair of sliding surfaces (100, 101) is improved, even if a thrust bearing (53) is used in a boundary or a mixed lubrication area, the sliding surfaces (100, 101). ) Wear amount is small, and the scroll compressor does not substantially deteriorate in performance. Further, according to this scroll compressor, the control is not complicated and the cost is not high.

  The invention according to claim 6 is the invention according to claim 5, wherein the thrust bearing (53) has a plurality of floating island-shaped pressure receiving portions (83) surrounded by the groove (85) and independent of each other. The sliding surface (100) of the first sliding surface (100) and the portion facing the pressure receiving portion (83) of the one sliding surface (100) have the other substantially flat sliding surface (101), The pressure receiving portion (83) has a sag portion (83b) formed at the peripheral edge of the pressure receiving portion (83) and a flat portion (83a) inside the sag portion (83b). The standard deviation σ1 of the surface roughness on the sliding surface (100) and the standard deviation σ2 of the surface roughness on the other sliding surface (101) are each 0.08 μm or less.

  As a result, an oil film is easily formed on the floating island-shaped pressure receiving portion (83) surrounded by the groove (85), and it is easy to form a fluid lubrication state, and the pair of sliding surfaces (100, 101). Since the surface roughness of each is small, the wear amount of the sliding surface (100, 101) is small even when used in the boundary or the mixed lubrication region, and the anti-seizure property is enhanced, and the scroll type compressor is deteriorated in performance. Substantially does not occur.

  The invention according to claim 7 is the invention according to claim 5 or 6, wherein a fluid containing lubricating oil is supplied to the sliding surfaces (100, 101) of the thrust bearing (53), and the other sliding surface is provided. The sliding speed of the pressure receiving part (83) with respect to (101) becomes 0.5 m / sec or more, and a load with an average surface pressure of 0.5 to 20 MPa is applied to the pressure receiving part (83). It is used in a state where the viscosity is 0.1 to 10 cst.

  Thereby, the fluid lubrication state of the thrust bearing (53) is ensured, and wear generated on the other sliding surface (101) due to the boundary or mixed lubrication at the time of start-up or liquid back is reduced.

  The invention according to claim 8 is the invention according to any one of claims 5 to 7, wherein the other sliding surface (101) is increased in hardness by quenching or film formation. Features.

  Thereby, the other sliding surface (101) can effectively increase the hardness of the surface.

  The invention according to claim 9 is the invention according to any one of claims 1 to 4, wherein the hardness of the other sliding surface (101) is higher than that of the one sliding surface (100), and The difference in Vickers hardness between both sliding surfaces (100, 101) is 500 HV or more.

  Thus, the same effects as those of the fifth to eighth aspects of the invention can be achieved.

  The invention according to claim 10 is the invention according to claim 8, wherein each of the one sliding surface (100) and the other sliding surface (101) is formed of a steel material, and both sliding surfaces. The amount of retained austenite in the vicinity of the surface in (100, 101) is 5% by volume or more.

  Thus, the same effect as that of the first to fourth aspects of the invention can be achieved.

  In addition, the code | symbol in the parenthesis attached | subjected to each said means is an example which shows a corresponding relationship with the specific means as described in embodiment mentioned later.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a longitudinal sectional view showing a scroll compressor 11 in the present embodiment. Hereinafter, a compressor for a hot water heater used in a refrigeration circuit using carbon dioxide refrigerant and the pressure of discharged carbon dioxide exceeding the critical pressure will be described as an example, but the present invention is not limited to this. Absent.

  The scroll compressor 11 in this embodiment is a hermetic electric compressor in which an electric motor unit 27 and a compression mechanism unit 10 are accommodated in a hermetic container 13.

  The sealed container 13 includes a cylindrical case 13a having a cylindrical shape, a motor side end case 13b and a compression mechanism side end case 13c assembled to both ends of the cylindrical case 13a.

  The electric motor unit 27 includes a stator 25 fixed to the inner peripheral surface of the cylindrical case 13 a and a rotor 23 fixed to the shaft 21 that is rotationally driven by the electric motor unit 27.

  The compression mechanism unit 10 is a movable scroll that revolves by a middle housing 15 fixed at a position adjacent to the stator 25 in the cylindrical case 13a and a crank mechanism 28 supported by a main bearing 17 provided in the middle housing 15. 32 and a fixed scroll 38 which is fixed to the cylindrical case 13a on the side opposite to the stator 25 of the middle housing 15 and which is disposed to face the movable scroll 32 and forms a working chamber 45 which will be described later.

  The shaft 21 is formed by a sub-bearing 19 fixed to a disk-like support member 14 provided between the stator 25 and the motor side end case 13b in the cylindrical case 13a, and the main bearing 17. It is supported almost horizontally.

  The movable scroll 32 includes a substantially disc-shaped movable side plate 33, a movable side spiral 41 erected in an involute curve from the end surface of the movable side plate 33 toward the fixed scroll 38, and an end surface opposite to the movable side spiral 41. A boss portion 35 is provided in a cylindrical shape toward the middle housing 15 side.

  The fixed scroll 38 includes a fixed side plate 39 fixed to the cylindrical case 13a, and a fixed side spiral 43 formed by a spiral groove provided on the end surface of the fixed side plate 39 on the movable scroll 32 side.

  The middle housing 15 has a three-stage cylindrical shape that gradually increases in diameter from the motor part 27 side toward the fixed scroll 38 side, and the smallest diameter cylinder 15a close to the motor part 27 constitutes the main bearing 17. The middle cylinder 15b constitutes a crank chamber 29 for accommodating the crank mechanism 28, and the largest diameter cylinder 15c near the fixed scroll 38 forms a scroll accommodating portion 31 for accommodating the movable scroll 32 therein, and the cylindrical case 13a. It is being fixed to the inner peripheral surface of this by fixing means, such as shrink fitting.

  The crank mechanism 28 includes an eccentric shaft 37 and a boss portion 35 of the movable scroll 32 that are integrally provided at the end portion of the shaft 21 on the compression mechanism portion 10 side. The eccentric portion 37 is provided so as to be eccentric by a predetermined amount e (FIG. 2A) from the axial center of the main bearing 17 and the auxiliary bearing 19. This eccentricity e is the revolution radius of the movable scroll 32.

  On the end surface on the side of the movable scroll 32 (hereinafter referred to as a disc portion scroll side end surface 15e) of the disc portion 15d that connects the large diameter cylinder 15c and the middle cylinder 15b constituting the middle housing 15, an Oldham (not shown) is provided. A coupling is disposed to prevent the movable scroll 32 from rotating. Thereby, only the revolution of the movable scroll 32 is permitted. The compression mechanism unit 10 includes a plurality of working chambers 45 formed by meshing of the movable-side spiral 41 and the fixed-side spiral 43, and the movable scroll 32 pivots with respect to the fixed scroll 38 to reduce the volume. The refrigerant supplied to the suction chamber 46 communicating with the outermost peripheral side of the spiral 43 is compressed.

  A thrust bearing 53 is disposed between the disk portion scroll-side end surface 15e and the end surface on the side where the boss portion 35 of the movable scroll 32 is provided (hereinafter referred to as the movable scroll back surface 32a). The thrust bearing 53 has an axial force that the movable side plate 33 receives as a result of the difference between the compression reaction force when compressing the refrigerant and the thrust direction force due to the pressure on the movable scroll back surface 32a side (in this embodiment, This is a sliding bearing that slides the movable scroll rear surface 32a and the disk portion scroll side end surface 15e while receiving the force from the fixed scroll 38 toward the disk portion 15d. The thrust bearing 53 will be described in detail later.

  The suction chamber 46 is provided on the side surface of the fixed side plate 39, and is connected to a suction pipe 47 that passes through the cylindrical case 13a and sucks refrigerant from a refrigerant circuit outside the sealed container 13.

  A discharge port 49 that penetrates the fixed side plate 39 in the axial direction is provided at the center of the fixed side spiral 43. The refrigerant compressed by the movable scroll 32 and the fixed scroll 38 is discharged from the discharge port 49 to the discharge chamber 50.

  The discharge chamber 50 is provided on an end surface of the fixed side plate 39 on the side opposite to the movable scroll 32 (hereinafter referred to as a fixed scroll back surface 38a) and an end surface on the fixed side plate 39 side of the separator block 55 fixed to the fixed scroll back surface 38a. It is comprised by the recessed part. A discharge valve 61 for preventing the discharged refrigerant from flowing backward is disposed in the discharge chamber 50.

  The high-temperature and high-pressure refrigerant discharged into the discharge chamber 50 is guided to the oil separator 63 through the refrigerant flow path 57 extending upward from the discharge chamber 50.

  The oil separator 63 is a centrifugal oil separator having an inner cylinder 63a and an outer cylinder 63b, and has a double cylindrical shape.

  The refrigerant flow path 57 extends upward from the discharge chamber 50 along the fixed scroll back surface 38a, and then is connected to the space between the inner cylinder 63a and the outer cylinder 63b of the centrifugal oil separator 63 in a substantially tangential direction. Yes. The refrigerant that has flowed into the space between the inner cylinder 63a and the outer cylinder 63b from the substantially tangential direction swirls in the space between the inner cylinder 63a and the outer cylinder 63b, and the oil contained in the refrigerant is centrifuged. It passes through the inner cylinder 63a, passes through the discharge pipe 59, and is sent to the refrigerant circuit outside the sealed container 13. Here, it is preferable that the oil in the present embodiment is mainly composed of a lubricating oil obtained by mixing any one of polyalkylene glycol, polyvinyl ether or polyol ester, or a plurality of these.

  The outer cylinder 63b of the oil separator 63 is constituted by a cylindrical hole provided in the separator block 55, and the inner cylinder 63a is fixed in the cylindrical hole constituting the outer cylinder 63b by fixing means such as press fitting and circlip. It is fixed by.

  The discharge pipe 59 penetrates the inside and outside of the sealed container 13 and is inserted in an airtight manner into the upper end of a cylindrical hole constituting the outer cylinder 63b. In addition, the space between the separator block 55 and the compression mechanism side end case 13c has a low-pressure atmosphere as compared with the pressure of the discharged refrigerant.

  The oil separated by the oil separator 63 moves downward along the inner wall surface of the outer cylinder 63b due to gravity, and is pressurized through a small-diameter hole 64 provided at the lower end of the cylindrical hole constituting the outer cylinder 63b. It is stored in the oil storage chamber 65.

  The high-pressure oil storage chamber 65 is provided in the separator block 55 and is located below a cylindrical hole that forms the discharge chamber 50 and the outer cylinder 63b. In order to increase the amount of high-pressure oil that can be stored in the high-pressure oil storage chamber 65, the separator block 55 is compressed in the lower part constituting the high-pressure oil storage chamber 65 rather than the upper part corresponding to the cylindrical hole constituting the outer cylinder 63b. It protrudes to the mechanism side end case 13c side.

  The oil stored in the high-pressure oil storage chamber 65 is guided to an oil passage 69 provided inside the movable side plate 33 through an oil return passage 67 penetrating the fixed side plate 39 below the fixed side spiral 43. A small-diameter restricting portion 67 a is provided at the outlet of the oil return passage 67.

  The inlet of the oil passage 69 opens to the surface of the movable side plate 33 on which the movable spiral 41 is provided, and this inlet is provided with a counterbore so as to have a larger cross-sectional area than other parts of the oil passage 69. It has been. The inlet of the oil passage 69 is in intermittent communication with the outlet of the oil return passage 67 by the revolving motion of the movable scroll 32. Further, the outlet of the oil passage 69 opens in the inner wall of the boss portion 35 so as to communicate with the space between the end portion of the shaft 21 and the bottom surface of the boss portion 35.

  The oil stored in the high-pressure oil storage chamber 65 has a high pressure due to the discharge pressure of the refrigerant, but is intermittent between the oil return passage 67 and the oil passage 69 due to the revolving motion of the throttle portion 67a and the movable scroll 32. By communication, the pressure is reduced to a desired pressure.

  The oil guided to the space between the end portion of the shaft 21 and the bottom surface of the boss portion 35 flows into an oil passage 71 that penetrates the shaft 21 in the axial direction.

  The oil that has passed through the oil passage 71 is guided between the motor-side end case 13 b and the support member 14 in the sealed container 13. The support member 14, the middle housing 15, and the fixed side plate 39 have a gap (not shown) between the cylindrical case 13 a, and the oil guided between the motor side end case 13 b and the support member 14 is sealed in the sealed container 13. It is stored below in the whole area. A low pressure oil storage chamber 66 is formed below the entire region in the sealed container 13.

  The oil stored in the low-pressure oil storage chamber 66 reaches the scroll storage portion 31 through the oil return hole 73 provided below the disc portion 15 d of the middle housing 15.

  In the oil passage 71, radial holes 71 a and 71 b are provided to branch from the oil passage 71 at portions corresponding to the main bearing 17 and the sub-bearing 19.

  The outlet of the radial hole 71a communicates with a shaft groove 21a provided in the shaft 21, and the oil flowing into the radial hole 71a lubricates the main bearing 17, the crank mechanism 28, and the thrust bearing 53, and then stores the scroll. Part 31 is reached. In the middle cylinder 15b, an oil groove 72 for communicating the radial hole 71a and the thrust bearing 53 is formed in the upper part of the shaft 21 in order to guide oil to the thrust bearing 53 above the shaft 21. Yes.

  On the other hand, the oil that has flowed into the radial hole 71 b lubricates the auxiliary bearing 19, then falls into the low-pressure oil storage chamber 66, and reaches the scroll storage portion 31 through the oil return hole 73.

  The oil return passage 67, the oil passages 69 and 71, and the radial hole 71a supply oil to the thrust bearing 53 by a pressure difference between the pressure of the oil separated by the oil separator 63 and the pressure at the portion where the thrust bearing 53 is disposed. Oil supply means to do.

  The oil that has reached the scroll housing 31 is supplied to the sliding surfaces of the movable scroll 32 and the fixed scroll 38, is compressed together with the refrigerant in the working chamber 45, and is separated from the refrigerant by the oil separator 63 again.

  Next, the thrust bearing 53 of the present invention will be described. The thrust bearing 53 in the present embodiment includes a scroll side plate 53a fixed to the movable scroll back surface 32a, and a housing side plate 53b fixed to the disk portion scroll side end surface 15e.

  The scroll side plate 53a is formed in a donut shape, and the boss portion 35 penetrates through the hole in the center. A substantially circular unevenness as shown in FIG. 2 is formed on the end surface of the scroll side plate 53a that is in sliding contact with the housing side plate 53b.

  2A is a cross-sectional view taken along the line AA in FIG. 1 so that the end surface of the scroll side plate 53a that is in sliding contact with the housing side plate 53b can be seen. FIG. 2A is a cross-sectional view taken along the line B-B of FIG. 2A so that a substantially circular concavo-convex surface can be seen, and FIG. 2C is an enlarged view of a portion indicated by reference numeral G in FIG. In FIG. 2A and FIG. 4 to be described later, the housing side plate 53b and the edge 53c on the inner diameter side of the housing side plate 53b shown by broken lines do not originally appear in the cross sections of FIG. 2A and FIG. However, in order to show the relative positional relationship with the housing side plate 53a, the position is shown on FIG. 2 (a) and FIG.

  The substantially circular concave / convex concave portion is constituted by a plurality of grooves 85. The plurality of grooves 85 are supplied with oil by the oil supply means and intersect with each other in a mesh shape. The intersection 85a has a groove width wider than that of other portions. Further, the bottom surface of the groove 85 shown in FIG. 2B has a surface roughness of 12.5 Rz or more, and the surface roughness is larger than that of the pressure receiving portion 83 described later. Of the plurality of grooves 85, a groove (hereinafter referred to as an outermost peripheral groove) 85b located on the outermost circumference makes a round around the edge of the scroll side plate 53a along the edge of the scroll side plate 53a. Between the outermost peripheral groove 85b and the edge of the scroll side plate 53a, an outer peripheral seal portion 81 that reduces the amount of lubricating oil flowing out from the sliding surface by always making sliding contact with the housing side plate 53b in the entire periphery. Forming. The seal portion 81 includes a convex portion 81c that is curved so as to project inward in the radial direction of the scroll side plate 53a by meandering of the outermost peripheral groove 85b. As shown in FIG. 2C, the convex portion 81 c has a role of drawing oil from all directions facing the convex portion 81 c by a turning motion of the movable scroll 32 and forming an oil film, as in the pressure receiving portion 83 described later. Plays.

  Between the plurality of grooves 85, a convex portion surrounded by the grooves 85 is a floating island-shaped pressure receiving portion 83, and the pressure receiving portion 83 is formed in a substantially circular shape and has the outermost periphery. Are arranged in a staggered manner in accordance with the meandering of the grooves 85. The diameter of the pressure receiving portion 83 is e or more and less than 2e with respect to the revolution radius e of the movable scroll 32 in order to reduce foreign matter discharge and surface pressure. It is desirable that the portion 83 occupies 50% or more. Further, the upper surface of the seal portion 81 and the pressure receiving portion 83 are made smooth as sliding surfaces and are located in substantially the same plane. As shown in FIG. 2B, taper portions or sag portions 81b and 83b for generating a wedge effect of the oil film are provided at the edges of the seal portion 81 and the pressure receiving portion 83, and the housing side plate 53b. The flat portions 81a and 83a are in sliding contact with each other.

  In the present embodiment, since the thrust bearing 53 is provided with irregularities on the scroll side plate 53a fixed to the movable scroll 32, a plurality of grooves 85 forming the irregularities are formed along with the turning of the movable scroll. 21 is configured to move relative to 21.

  The housing side plate 53b is a plain flat surface having a mirror-finished sliding surface with the scroll side plate 53b, and has a donut shape like the scroll side plate 53a.

  With the above configuration, the oil retained in the groove 85 is wedged by the sag portion and the taper portions 81b and 83b formed around the pressure receiving portion 83 by the sliding contact between the scroll side plate 53a and the housing side plate 53b. As a result, the oil film 86 shown in FIG. The oil film 86 is in a state where the refrigerant is dissolved in the lubricating oil.

  Next, the thrust bearing 53 of this embodiment will be further described below.

  As shown in FIG. 5, the thrust bearing 53 has a pair of sliding surfaces 100 and 101. One sliding surface 100 is the surface of the scroll side plate 53a and faces the housing side plate 53b. The other sliding surface 101 is a surface of the housing side plate 53b and faces the scroll side plate 53a.

As described above, on one sliding surface 100, as shown in FIG. 2A, a large number of floating island-shaped pressure receiving portions 83 are formed. Moreover, as for the other sliding surface 101, the part facing the pressure receiving part 83 in one sliding surface 100 is substantially flat as shown in FIG. In the present embodiment, the other sliding surface 101 is a flat plane as a whole.
In FIG. 5, the groove 85 is shown, but this groove may be other grooves 85a and 85b.

  In this specification, “substantially flat” means mixing of the lubricant oil and the refrigerant interposed between the pressure receiving portion 83 and the portion of the other sliding surface 101 facing the pressure receiving portion 83. This means that the part is flat to the extent that pressure due to the wedge effect is generated in the fluid.

  As shown in FIG. 5, the surface on the other sliding surface 101 side of the pressure receiving portion 83 includes a sag portion 83b formed at the peripheral portion thereof, and a flat portion 83a that is connected to the sag portion 83b on the inside thereof. And have. The sagging part 83b is provided in the peripheral part of the pressure receiving part 83 into which the mixed fluid flows. In the present embodiment, the mixed fluid is drawn from the entire peripheral edge portion of the pressure receiving portion 83 by the turning motion of the movable scroll 32, so that the sag portion 83 b is formed on the entire peripheral edge portion of the pressure receiving portion 83.

One sliding surface 100 and the other sliding surface 101 can easily obtain a fluid lubrication state due to the wedge effect of the pressure receiving portion 83. However, at the time of starting the scroll compressor 11 or at the time of liquid back, a boundary or mixed lubrication may occur.
The liquid back is a phenomenon in which the liquid refrigerant is sucked into the scroll compressor 11 together with the gaseous refrigerant from the suction pipe 47, and the liquid refrigerant flows into the sliding surfaces 100 and 101. . Since the liquid refrigerant dilutes the lubricating oil on the sliding surfaces 100 and 101, boundary or mixed lubrication tends to occur on the sliding surfaces.

  Each of the sliding surface 100 and the other sliding surface 101 has a surface roughness, and the thickness of the oil film existing between the sliding surfaces 100 and 101 is the same as that of the sliding surfaces 100 and 101. It changes corresponding to the surface roughness.

When the surface roughness of the sliding surfaces 100 and 101 is large, the surface roughness is superior to the oil film thickness that can be formed, and the sliding surfaces are likely to contact each other.
From this viewpoint, the standard deviation of the surface roughness at the flat portion 83a of one sliding surface 100 is σ1, and the standard deviation of the surface roughness at the other sliding surface 101 is σ2 is 0.08 μm or less, respectively. It is preferable.

  When the standard deviations σ1 and σ2 of the initial surface roughness of the sliding surfaces 100 and 101 are larger than 0.08 μm, the standard deviations σ1 and σ2 of the surface roughness are 0.08 μm or less by performing the familiar operation. In addition, it is preferable to use the scroll compressor 11 after lowering to 0.04 μm or less. Usually, since the lower limit value of the standard deviations σ1 and σ2 of the surface roughness after the running-in operation is about 0.015 μm, the standard deviations σ1 and σ2 are 0.015 to 0.04 μm at least after the running-in operation. It is preferable.

  It is preferable that the pressure receiving portion 83 has the above-described relationship with respect to the revolution radius e. Further, the length of the sag portion 83b in the pressure receiving portion 83 measured along a virtual line passing through the center of the flat portion 83a is preferably 5 to 98% with respect to the radius of the pressure receiving portion 83, and It is preferably 30 to 50% in order to effectively generate a wedge effect in the mixed fluid.

  The distance between the pressure receiving portions 83 is preferably 200 to 500% in the circumferential direction of the scroll side plate 53a with respect to the diameter of the pressure receiving portion 83. Moreover, in the radial direction of the scroll side plate 53a, it is preferably 200 to 500%.

  In the thrust bearing 53, one sliding surface 100 and the other sliding surface 101 are each formed of a steel material. That is, the scroll side plate 53a and the housing side plate 53b are each formed from this steel material.

  Examples of the steel material that forms the sliding surfaces 100 and 101 include, for example, high carbon chrome bearing steel material, alloy steel material for machine structure, cold rolled steel plate material, nickel chrome steel material, nickel chrome molybdenum steel material, chrome steel material, Various steel materials defined by JIS standards such as chromium molybdenum steel materials, manganese steel materials for machine structures, manganese chromium steel materials, and structural steel materials with guaranteed hardenability are preferably used.

  More specifically, SUJ2, SUJ3 and SUJ4 are preferable as the high carbon chromium bearing steel. Moreover, as a carbon steel material for machine structures, SCr415, SCr420, SCr440, SCM415, SCM420, SNCM420, SCM435, SCM440SNCM630 are preferable. Moreover, as a cold-rolled steel plate material, SPCC, SPCD, SPCE, and SPCEN are preferable.

Moreover, the steel material which forms both sliding surfaces 100 and 101 has the austenite phase which is one of the Fe-C states of steel. The austenite phase is present as a large number of crystal grains in the vicinity of the surfaces of both sliding surfaces 100 and 101, and is dispersed between other Fe-C state phases (for example, martensite phase). Is preferred. This austenite phase is so-called retained austenite that is not martensite after quenching of the steel material.
In the vicinity of the surfaces of both sliding surfaces 100 and 101, the Fe—C state other than the austenite phase is preferably mainly a martensite phase.

  The steel material described above preferably has one or more elements selected from the group consisting of C, N, Mn, Ni, or Pd as the austenite phase forming element. A predetermined amount of retained austenite can be obtained by adjusting the austenite phase-forming element concentration in the steel material.

In the thrust bearing 53 of the present embodiment, the austenite phase is dispersed in the vicinity of the surfaces of the sliding surfaces 100 and 101, so that the amount of wear on the sliding surfaces is reduced. The reason is as follows.
When the thrust bearing 53 is used at the boundary or the mixed lubrication region at the time of start-up or liquid back, both sliding surfaces 100 and 101 are in contact with each other partially or completely, and the austenite of the contacted portion The phase is work hardened quickly. This work hardening occurs in a part of crystal grains of the austenite phase. As a result, in the crystal grains, the hardened portion is less likely to be worn, and the work-hardened austenite phase around the portion becomes a cushion, and wear of the sliding surfaces 100 and 101 is prevented.

  In addition, even when foreign matter such as wear powder enters between the sliding surfaces 100 and 101 and a boundary or mixed lubrication occurs, the sliding surfaces 100 and 101 have the same wear prevention effect. Played.

  The amount of retained austenite in the vicinity of the surfaces of both sliding surfaces 100 and 101 is 5% by volume or more, preferably 5 to 40% by volume, and more preferably 5 to 20% by volume.

  When the amount of retained austenite is 5% by volume or more, the amount of wear on both sliding surfaces 100 and 101 is effectively reduced. The sliding surfaces 100 and 101 may change the amount of retained austenite due to the use of the scroll compressor 11 due to an increase in temperature of the sliding surfaces or stress acting on the sliding surfaces. Therefore, the amount of retained austenite in the vicinity of the surfaces of the sliding surfaces 100 and 101 is set to a value of 5% by volume or more over the entire use period of the scroll compressor 11 during the manufacture of the scroll compressor 11. Keep it.

  On the other hand, if the amount of retained austenite is 40% by volume or more, the hardness of both sliding surfaces 100 and 101 is lowered, and conversely, the amount of wear increases. This is because the austenite phase has a lower hardness than the main martensite phase.

  Each of the sliding surface 100 and the other sliding surface 101 has a region where the amount of retained austenite is 5% by volume or more extending from the surface to a depth of 10 μm or more, preferably 10 to 200 μm. Furthermore, the region in which the amount of retained austenite is 5% by volume or more may extend over each of the scroll side plate 53a and the housing side plate 53b.

  For example, when running-in is performed before the scroll compressor 11 is used, the amount of retained austenite is 5 in each of the sliding surface 100 and the other sliding surface 101 in the state after the running-in operation. It is preferable that the area | region which is volume% or more is 10 micrometers or more from the surface.

  A known method can be used to measure the amount of retained austenite on each of the sliding surfaces 100 and 101. For example, it can be determined from the peak ratio of α (ferrite) phase and γ (austenite) phase obtained by X-ray measurement.

  In order to obtain both sliding surfaces 100 and 101 having a retained austenite amount in the above-mentioned range near the surface, the steel material may be subjected to quenching treatment, tempering treatment, carburizing treatment, nitrocarburizing treatment, or carburizing and nitriding treatment. preferable. Known conditions can also be used as the heat treatment conditions.

  Each of the above processes is preferably performed after each of the scroll side plate 53a and the housing side plate 53b is processed from a steel material into a shape having a predetermined dimension by machining, and then further finishing is preferably performed.

  As said carburizing process, well-known methods, such as a solid carburizing process, a liquid carburizing process, a gas carburizing process, and a vacuum carburizing process, are mentioned.

  Moreover, it is also preferable to perform the nitriding treatment on the steel material instead of the carburizing treatment. Examples of the nitriding treatment include a known method using ammonia or a nitriding compound. The nitrogen concentration in the vicinity of the surface of the sliding surfaces 100 and 101 after the nitriding treatment is preferably in the above-described range.

  Furthermore, it is also preferable to use the carburizing and nitriding treatment in order to subject the steel material to the nitriding treatment together with the carburizing treatment. Examples of the carburizing and nitriding treatment include subjecting a steel material to the nitriding treatment in a carburizing atmosphere.

  The treatment for increasing the concentration of carbon or nitrogen in the vicinity of the surface of the steel material is to adjust the amount of retained austenite in the vicinity of the surface to the above range and increase the hardness in the vicinity of the surface of the steel material, while maintaining the softness inside, This is preferable in improving the wear resistance and fatigue resistance of the scroll side plate 53a and the housing side plate 53b formed from the steel material.

  According to the scroll compressor 11 of the present embodiment described above, the thrust bearing 53 includes the austenite phase having a predetermined concentration in the vicinity of the surfaces of the sliding surfaces 100 and 101, so that the wear resistance is high. Even if the sliding bearing (53) is used in the boundary or the mixed lubrication region at the time of starting the scroll compressor 11 or at the time of liquid back, the amount of wear of the sliding surfaces 100 and 101 is small and the scroll is reduced. The type compressor is substantially free from performance degradation. Further, according to this scroll compressor, the control is not complicated and the cost is not high.

  Further, according to the present embodiment, each of the sliding surfaces 100 and 101 of the thrust bearing 53 is formed with a portion where the austenite phase is hardened and the wear resistance is improved from the surface to a predetermined depth. Even if the thrust bearing 53 is used in the boundary or the mixed lubrication region and the sliding surfaces 100 and 101 are worn, the function of the thrust bearing 53 is reliably maintained for a predetermined period.

  Further, according to the present embodiment, since the surface roughness of each of the pair of sliding surfaces (100, 101) is small, the wear amount of the sliding surfaces (100, 101) even when used in the boundary or the mixed lubrication region. There is little, and the seizure prevention property is improved.

  In this embodiment, since the bottom surface of the groove 85 has a rough surface, the lubricating oil can be reliably held on this rough surface. As a result, even if the scroll compressor 11 is operated in a state where the supply of oil to the sliding surface of the thrust bearing 53 is temporarily interrupted, the sliding surface is sufficiently provided by the oil retained on the bottom surface of the groove 85. Lubrication can be performed.

  Further, since the plurality of grooves 85 are provided in a mesh shape and the pressure receiving portion 83 surrounded by the grooves 85 is formed in a floating island shape, the entire periphery of the pressure receiving portion 83 is surrounded by the grooves, and the turning of the movable scroll 32 is performed. The oil film 86 by the wedge effect can be formed from all directions by the movement. Furthermore, since the groove width of the intersection 85a of the plurality of mesh-like grooves 85 is made thicker than other portions, the oil can be sufficiently distributed to the plurality of grooves 85.

  Further, since the pressure receiving portion 83 has a substantially circular floating island shape and is arranged in a staggered manner, the pressure receiving portions 83 can be arranged at a high density, and the oil film formation area per unit area can be increased to support a high load. .

  Further, since the groove 85 is provided on the scroll side plate 53 a fixed to the movable scroll 32, the groove 85 moves relative to the shaft 21 as the movable scroll 32 turns. As a result, the oil retained on the bottom surface of the groove 85 becomes droplets and is easily supplied to the sliding surface.

  Next, the positional relationship between the pressure receiving portion 83 provided on the scroll side plate 53a and the housing side plate 53b accompanying the revolution of the movable scroll 32 will be described with reference to FIG. FIG. 4 is a diagram showing how the scroll side plate 53a moves in the cylindrical case 13a as the movable scroll 32 revolves. The scroll side plate 53a moves along with the revolution of the movable scroll 32. It moves in the order of (b)-(c)-(d). Here, when the envelope drawn by the inner edge 53c of the housing side plate 53b by the relative movement of the scroll side plate 53a and the housing side plate 53b is H, the plurality of pressure receiving portions 83 provided on the scroll side plate 53a are: Provided only on the outer diameter side of the envelope H on the scroll side plate 53a. Thereby, even if the movable scroll 32 moves along with the revolving motion, the pressure receiving portion 83 does not protrude from the housing side plate 53b, and a sufficient oil film is formed by the oil held by the plurality of grooves 85. Can do.

  The envelope H in the present embodiment is a circle that is larger than the edge 53c on the inner diameter side of the housing side plate 53b by the turning radius of the movable scroll 32.

  Next, the scroll type compressor 11 of 2nd Embodiment of this invention is demonstrated. The second embodiment is different from the first embodiment described above in the configuration of the sliding surfaces 100 and 101, and is otherwise the same as the first embodiment.

In the scroll compressor 11 according to the second preferred embodiment of the present invention, the hardness of the other sliding surface 101 in the thrust bearing 53 is higher than that of the one sliding surface 100. The difference in Vickers hardness between the sliding surfaces 100 and 101 is 500 HV or more, preferably 700 HV or more.
The Vickers hardness of one sliding surface 100 is preferably 700 to 850 HV. The Vickers hardness of the other sliding surface 101 is preferably 1500 to 2500 HV.

The thrust bearing 53 of this embodiment will be further described below.
Each of the scroll side plate 53a and the housing side plate 53b constituting the thrust bearing 53 is preferably formed of a steel material as in the above embodiment.
And the housing side plate 53b which forms the other sliding face 101 may be used as a steel material, or may be a steel material whose hardness is increased by a quenching process or a film forming process. When the other sliding surface 101 is used as a steel material, the steel material forming the other sliding surface 101 has a Vickers hardness difference of 500 HV or more than the steel material forming the one sliding surface 100. It is preferable to use it.

  When the hardness of the vicinity of the surface of the other sliding surface 101 is increased by the surface treatment such as the quenching treatment, the portion whose hardness is increased, that is, the Vickers hardness than the one sliding surface 100. The depth from the surface of the region having the difference of 500 HV or more is preferably 10 μm or more, more preferably 10 to 200 μm. Furthermore, the Vickers hardness difference of the entire housing side plate 53b may be 500 HV or more than that of the one sliding surface 100.

  Examples of the surface treatment include the quenching process, the carburizing process, the nitriding process, or the carburizing and nitriding process described in the first embodiment. And the method of performing surface treatment of steel materials is the same as that of the said 1st Embodiment.

  Further, when the hardness of the vicinity of the other sliding surface 101 is increased by the film formation process, the thickness of the formed film is preferably 1 to 5 μm.

  As the type of film formed on the other sliding surface 101, for example, a chromium nitride (CrN) film, a diamond-like carbon (DLC) film, titanium nitride (TiN), or the like is preferable.

  As a method of forming the chromium nitride (CrN) film or the diamond-like carbon (DLC) film on the other sliding surface 101, a known method such as PVD or CVD can be used.

  According to the scroll compressor 11 of the present embodiment described above, the thrust bearing 53 has the Vickers hardness of the other sliding surface 101 higher than that of the first sliding surface 100 by 500 HV or higher, so that the scroll type compression is performed. Even when the slide bearing 53 is used at the boundary or the mixed lubrication region at the time of starting the machine 11 or at the time of liquid back, the indentation generated on the other sliding surface 101 can be kept small and shallow. As a result, the amount of wear on the other sliding surface 101 is reduced, so that the performance of the scroll compressor is not substantially reduced.

  Further, according to the present embodiment, the hardness of the other sliding surface 101 can be increased as appropriate according to the use conditions of the thrust bearing 53 by the surface treatment such as the quenching treatment or the film forming treatment described above. Specifically, by adjusting the surface treatment conditions, a region having a desired hardness can be formed from the other sliding surface 101 to a predetermined depth. Further, by adjusting the conditions of the film formation process, a film having a desired hardness can be formed on the other sliding surface 101 with a predetermined thickness.

  The scroll compressor 11 of the first embodiment or the second embodiment described above is used under various usage conditions depending on the application. Particularly, in the scroll compressor 11, it is preferable that the thrust bearing 53 is used exclusively in the fluid lubrication region from the viewpoint of ensuring the durability.

  From this point of view, the scroll compressor 11 of each of the above embodiments supplies the mixed fluid containing the lubricating oil and the refrigerant to the sliding surfaces 100 and 110 of the thrust bearing as the sliding bearing 53, and the other slide. The sliding speed of the pressure receiving part 83 with respect to the moving surface 101 is set to 0.5 m / sec or more, a load of an average surface pressure of 0.5 to 20 MPa is applied to the pressure receiving part 83, and the kinematic viscosity in the usage state of the mixed fluid is 0. .1 to 10 cst. The lubricating oil is preferably contained in the oil.

  The use conditions of the scroll compressor 11 will be further described. In the scroll compressor 11 of each of the above embodiments, the mixed fluid is supplied to the sliding surfaces 100 and 110 of the thrust bearing 53 by the oil supply means. The

  Further, when the movable scroll 32 revolves, one sliding surface 100 fixed to the movable scroll 32 slides with respect to the other sliding surface 101 fixed to the middle housing 15. This sliding speed is 0.5 m / sec or more, preferably 0.6 to 5 m / sec with respect to the other sliding surface 101.

  In addition, the thrust bearing 53 has the pressure receiving portion 83 on the other sliding surface 101 as a result of the difference between the compression reaction force when compressing the refrigerant and the force in the thrust direction due to the pressure on the movable scroll back surface 32a side. A load is applied. The average surface pressure of the pressure receiving portion 83 due to this load is 0.5 to 20 MPa, preferably 2 to 15 MPa.

Further, the mixed fluid has a kinematic viscosity of 0.1 to 10 cst, preferably 4 to 10 cst on the sliding surfaces 100 and 101 of the thrust bearing 53 under the use conditions of the scroll compressor 11 described above. 1 cst is about 1 × 10 ⁻⁶ m ² / sec.

  By using the scroll compressor 11 of each of the above embodiments under the above-described use conditions, an oil film is formed between the pressure receiving portion 53 and the portion of the other sliding surface 101 facing the pressure receiving portion 53. Therefore, the thrust bearing 53 can be used exclusively in a fluid lubrication state. As a result, wear in the thrust bearing 53 can be prevented, and the scroll type compressor 11 can be used for a long time while maintaining the performance.

  As mentioned above, although preferable embodiment of this invention was described, this invention is not restrict | limited to embodiment mentioned above.

  For example, in the above embodiments, the pressure receiving portion 83 has a substantially circular shape in the above embodiments, but the pressure receiving portion 83 may have an elliptical shape, an elliptical shape, a triangular shape, or a polygonal shape such as a quadrangular shape. In the above embodiment, the pressure receiving portions 83 are formed in a substantially circular shape and arranged in a staggered manner. However, the present invention is not limited to this, and may be formed in a bowl shape or a linear shape. .

  Moreover, in the said 1st Embodiment, although the part whose residual austenite amount is 5 volume% or more was formed in the one sliding surface 100 whole, the part whose residual austenite amount is 5 volume% or more is pressure-receiving. It may be only near the surface of the portion 83.

  In the second embodiment, each of the one sliding surface 100 and the other sliding surface 101 is made of steel, and the amount of retained austenite near the surface of both sliding surfaces 100 and 101 is 5 volumes. % Or more.

  In the above embodiment, the outer peripheral seal portion 81, the pressure receiving portion 83, and the groove 85 are formed in the scroll side plate 53a. However, the present invention is not limited to this, and the fixed side sliding surface 53b of the scroll housing recess 31 is not limited thereto. You may form in. That is, the other sliding surface 101 may be fixed to the movable scroll 38.

  In the above embodiment, the oil supply means for supplying the oil to the thrust bearing 53 by the pressure difference between the pressure of the oil separated by the oil separator 63 and the pressure of the portion where the thrust bearing 53 is disposed is adopted. The present invention is not limited to this, and any configuration may be used as long as oil is guided to the thrust bearing 53, and the oil supply means does not have to use a pressure difference.

  The requirements in one embodiment described above can be interchanged with each other as appropriate.

  Hereinafter, the effect of the sliding surfaces 100 and 101 in the scroll compressor according to the present invention will be further described with reference to examples of the present invention and comparative examples for comparison with the present invention. However, the present invention is not limited to such examples.

[Example 1]
SUJ2 (nitrogen quenching and tempering treatment) is used as a test piece for the scroll side plate 53a having one sliding surface 100, and SUJ2 (immersion) is similarly used as a test piece for the housing side plate 53b having the other sliding surface 101. Example 1 was obtained using a nitrogen quenching and tempering process. The amount of retained austenite near the surface of one sliding surface 100 was 10% by volume, and the amount of retained austenite near the surface of the other sliding surface 101 was 10% by volume. The amount of retained austenite was measured by the method described above.

[Example 2]
As a test piece of the scroll side plate 53a having one sliding surface 100, SCr415 (carburizing / nitrogen quenching treatment) is used, and as a test piece of the housing side plate 53b having the other sliding surface 101, SUJ2 (quenching / tempering treatment). Example 2 was obtained in the same manner as in Example 1 except that The amount of retained austenite near the surface of one sliding surface 100 was 8% by volume, and the amount of retained austenite near the surface of the other sliding surface 101 was 10%.

[Example 3]
SUJ2 (nitrogen quenching and tempering treatment) was used as a test piece of the scroll side plate 53a having one sliding surface 100. As a test piece of the housing side plate 53b having the other sliding surface 101, SUJ2 (nitrogen quenching and tempering treatment) was used, and a CrN film having a thickness of 3 ± 1 μm was formed on the other sliding surface 101. . In this way Example 4 was obtained.
One sliding surface 100 had a Vickers hardness of 700 HV, the other sliding surface 101 had a Vickers hardness of 1500 HV, and the difference between the two sliding surfaces was 800 HV.

[Example 4]
Example 5 was obtained in the same manner as Example 4 except that a DLC film having a thickness of 2 ± 1 μm was formed on the other sliding surface 101.
One sliding surface 100 had a Vickers hardness of 700 HV, the other sliding surface 101 had a Vickers hardness of 2000 HV, and the difference between the two sliding surfaces was 1300 HV.

[Comparative Example 1]
SK5 (quenching and tempering treatment) is used as a test piece of the scroll side plate 53a having one sliding surface 100, and SUJ2 (quenching and tempering treatment) is used as a test piece of the housing side plate 53b having the other sliding surface 101. Comparative Example 1 was obtained in the same manner as Example 1 except that it was used. The amount of retained austenite near the surface of one sliding surface 100 was 4% by volume, and the amount of retained austenite near the surface of the other sliding surface 101 was 10% by volume. Moreover, the Vickers hardness of one sliding surface 100 was 650 HV, the Vickers hardness of the other sliding surface 101 was 700 HV, and the Vickers hardness difference between both sliding surfaces was 50 HV.

[Evaluation of wear amount]
Using Examples 1 to 4 and Comparative Example 1 described above, the amount of wear was evaluated as follows.
The wear amount was evaluated using a barbell plate testing machine shown in FIG. The barbell plate testing machine has a barbell 103 in which a pair of disks are fixed to a cylindrical shaft at an interval, and a plate 104 on which the barbell is placed.
Each of the pair of disks is made of a test piece of the housing side plate 53b, the combination of the plate 104 made of the test piece of the scroll side plate 53a (hereinafter also referred to as “set A”), and each of the pair of disks is made of the scroll side plate 53a. A combination (hereinafter also referred to as “set B”) prepared from the test piece and the plate 104 prepared from the test piece of the housing side plate 53b was prepared.

  Each of the pair of disks had an outer diameter of 14 mm and a thickness of 5 mm. The length between the pair of disks in the barbell 103 was 21 mm. The plate 104 had four sides of 30 mm in length and a thickness of 1.5 to 6 mm, and was different depending on the test piece.

The plate 104 is immersed in the lubricating oil, and the sliding surface between the barbell 103 and the plate 104 is also immersed in the lubricating oil. In the test, after the plate 104 is rotated at a predetermined rotation speed for a predetermined time in a state where a predetermined load is applied to the barbell 103 from above, the wear amount of each of the test pieces of the barbell 103 and the plate 104 is measured. It is.
The measurement conditions were performed under a plurality of conditions by combining the load and the rotational speed. Moreover, this measurement condition was suitably adjusted for every test piece. Specifically, the load was in the range of 0 to 1000 N (surface pressure of 0 to 500 MPa), and the rotation speed was in the range of 0 to 2000 rpm (sliding speed of 0 to 2 m / sec).

First, the specific wear amount of Example 1 was measured as follows.
Using a barbell plate tester, a plurality of measurements with different surface pressures × sliding distances were performed to measure the wear amount of the test piece on the barbell 103 side and the wear amount of the test piece on the plate 104 side. The sliding distance was determined by the number of rotations × time. The amount of wear was the volume at which the test piece decreased due to wear. The measurement was performed for each of set A and set B of Example 1. The lubrication state between the barbell 103 and the plate 104 was boundary lubrication.
Then, using the obtained measurement results, the surface pressure × sliding distance was plotted on the horizontal axis and the wear amount was plotted on the vertical axis, and the specific wear amount was determined from the slope. The specific wear amount was determined for each of the sliding surface 100 and the other sliding surface 101.

Next, the estimated wear amount of Example 1 was determined as follows. Here, the estimated wear amount is a value obtained by estimating the wear amount in the actual machine using the specific wear amount.
Using the surface pressure and sliding distance of the thrust bearing 53 when the actual machine was operated under predetermined conditions, the wear amount A under boundary lubrication conditions was determined from specific wear amount × surface pressure × sliding distance. Then, the estimated wear amount in the mixed lubrication state was obtained from the wear amount A in consideration of the oil film parameter. The estimated amount of wear was determined for each of the sliding surface 100 and the other sliding surface 101.
For Examples 2 to 4 and Comparative Example 1, the estimated wear amount was determined in the same manner.
The results are shown in Table 1.

  As shown in Table 1, the estimated wear amount of Examples 1 to 4 is smaller than that of Comparative Example 1. In particular, the wear amount of Examples 3 and 4 is small, and the wear resistance is excellent.

BRIEF DESCRIPTION OF THE DRAWINGS The longitudinal cross-sectional view which shows the scroll compressor which is one embodiment of this invention. It is a figure which shows the movable side sliding surface of the thrust bearing of the scroll compressor shown in FIG. The figure which shows the formation state of the oil film in the island-shaped pressure-receiving part of the movable side sliding surface shown in FIG. 2, and its pressure. It is the figure which showed a mode that the scroll side plate 53a moved within the cylindrical case 13a with the revolution of the movable scroll 32. FIG. It is a schematic diagram which expands and shows the principal part of the sliding surface of a thrust bearing. It is a schematic diagram explaining the evaluation method of wear amount.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Compression mechanism part 15 Middle housing 27 Electric motor part 53 Thrust bearing 53a Scroll side plate 53b Housing side plate 81 Outer periphery seal part 83 Pressure receiving part 85 Groove 85a Intersection 86 Oil film 100 One sliding surface 101 The other sliding surface

Claims (10)

In a scroll compressor comprising a fixed scroll (38) and a movable scroll (32) that compresses fluid by turning with respect to the fixed scroll (38) by a rotating shaft (21),
The thrust bearing (53) receives an axial force received by the movable scroll (32). The thrust bearing (53) includes one sliding surface (100) and the one sliding surface (100). And the other sliding surface (101) opposite to
The one sliding surface (100) or the other sliding surface (101) is fixed to the movable scroll (32),
Each of the one sliding surface (100) and the other sliding surface (101) is made of steel, and the amount of retained austenite in the vicinity of the surfaces of both sliding surfaces (100, 101) is 5% by volume. A scroll compressor characterized by the above. The thrust bearing (53) includes one sliding surface (100) having a plurality of floating island-shaped pressure receiving portions (83) surrounded by a groove (85) and independent from each other, and the one sliding surface (100). And the portion facing the pressure receiving portion (83) has the other substantially flat sliding surface (101),
The pressure receiving portion (83) includes a sag portion (83b) formed at a peripheral portion of the pressure receiving portion (83), and a flat portion (83a) inside the sag portion (83b),
The standard deviation σ1 of the surface roughness on the one sliding surface (100) and the standard deviation σ2 of the surface roughness on the other sliding surface (101) are 0.08 μm or less, respectively. The scroll compressor according to claim 1.   Fluid containing lubricating oil is supplied to the sliding surfaces (100, 101) of the thrust bearing (53), and the sliding speed of the pressure receiving portion (83) with respect to the other sliding surface (101) is 0.5 m / sec. Thus, the pressure receiving portion (83) is loaded with an average surface pressure of 0.5 to 20 MPa, and is used in a state where the kinematic viscosity in use of the fluid is 0.1 to 10 cst. Item 3. The scroll compressor according to item 1 or 2.   Each of the one sliding surface (100) and the other sliding surface (101) has a region in which the amount of retained austenite is 5% by volume or more extending over a depth of 10 micrometers or more from the surface. The scroll compressor according to any one of claims 1 to 3, wherein the scroll compressor is provided. In a scroll compressor comprising a fixed scroll (38) and a movable scroll (32) that compresses fluid by turning with respect to the fixed scroll (38) by a rotating shaft (21),
The thrust bearing (53) receives an axial force received by the movable scroll (32). The thrust bearing (53) includes one sliding surface (100) and the one sliding surface (100). And the other sliding surface (101) opposite to
The one sliding surface (100) or the other sliding surface (101) is fixed to the movable scroll (32),
The hardness of the other sliding surface (101) is higher than that of the one sliding surface (100), and the Vickers hardness difference between the two sliding surfaces (100, 101) is 500 HV or more. Scroll type compressor. The thrust bearing (53) includes one sliding surface (100) having a plurality of floating island-shaped pressure receiving portions (83) surrounded by a groove (85) and independent from each other, and the one sliding surface (100). And the portion facing the pressure receiving portion (83) has the other substantially flat sliding surface (101),
The pressure receiving portion (83) includes a sag portion (83b) formed at a peripheral portion of the pressure receiving portion (83), and a flat portion (83a) inside the sag portion (83b),
The standard deviation σ1 of the surface roughness on the one sliding surface (100) and the standard deviation σ2 of the surface roughness on the other sliding surface (101) are 0.08 μm or less, respectively. The scroll compressor according to claim 5.   Fluid containing lubricating oil is supplied to the sliding surfaces (100, 101) of the thrust bearing (53), and the sliding speed of the pressure receiving portion (83) with respect to the other sliding surface (101) is 0.5 m / sec. Thus, the pressure receiving portion (83) is loaded with an average surface pressure of 0.5 to 20 MPa, and is used in a state where the kinematic viscosity in use of the fluid is 0.1 to 10 cst. Item 7. The scroll compressor according to Item 5 or 6.   The scroll compressor according to any one of claims 5 to 7, wherein the other sliding surface (101) has a hardness increased by a quenching process or a film forming process.   The hardness of the other sliding surface (101) is higher than that of the one sliding surface (100), and the Vickers hardness difference between the two sliding surfaces (100, 101) is 500 HV or more. The scroll compressor according to any one of claims 1 to 4.   Each of the one sliding surface (100) and the other sliding surface (101) is made of steel, and the amount of retained austenite in the vicinity of the surfaces of both sliding surfaces (100, 101) is 5% by volume. The scroll compressor according to claim 8, which is as described above.

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