JP2005308138A - Roller for thrust needle bearing and thrust needle bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a roller for a thrust needle bearing and a thrust needle bearing using the same capable of eliminating acoustic fault by elaborating the roller to keep accuracy of the roller within a intended range. <P>SOLUTION: Since roundness of a raceway surface is 1.5μm or less in section in a radial direction and a straight line part in parallel with an axial line is included in a section in an axial direction when crowning is applied at least from one end surface over the raceway surface in the roller for the thrust needle bearing, rolling of the roller is stabilized and noise can be kept low by adjustment of roundness. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a roller for a thrust needle bearing suitable for use in a compressor of a car air conditioner, a transmission for an automobile, and the like, and a thrust needle bearing using the roller.

For example, a variable capacity compressor is known as one type of compressor for a car air conditioner (also called a car cooler compressor). Generally, a variable displacement compressor supports a drive shaft rotatably with respect to a housing by a radial bearing, and a swash plate is connected to the drive shaft in a variable inclination angle, and swings with respect to the swash plate. A plate is slidably attached. A thrust bearing is disposed between the swash plate and the swing plate. One end of a plurality of piston rods is attached to the swing plate at equal intervals in the circumferential direction, and the other ends of the piston rods are connected to the piston. The piston is provided so as to slide inside a cylinder provided in the housing, and compresses and discharges the refrigerant gas flowing into the bore of the cylinder. That is, when the swash plate rotates, the oscillating plate performs a so-called razor-like operation, reciprocates the piston in the axial direction via the piston rod, and compresses and discharges the refrigerant gas (Patent Document). 1).
JP 2002-266754 A JP 2004-11667 A JP 2003-97570 A

  By the way, during operation of the compressor for a car air conditioner, the drive shaft receives a large force through the swash plate. Therefore, there are a thrust bearing that supports the drive shaft in the thrust direction with respect to the housing, and a radial bearing that supports the drive shaft in the radial direction. Necessary. Here, the thrust needle bearing has a plurality of rollers arranged radially and is rotated by receiving an axial load, and can receive a very large load even though its axial height is low (thin). Therefore, it is often used in car air conditioner compressors.

  However, in general thrust needle bearings, races and cages, which are race rings, are processed by pressing a plate material, not by cutting, bending the pressed material, heat-treating, barrel processing, and completing the process. Many things are made after the process. In the case of rollers, a processing method is used in which the wire is cut, polished, heat-treated, and barrel processed to reduce the cost of completion.

  For this reason, it can be said that the accuracy is somewhat rough compared to a rolling bearing such as a ball bearing having a general cutting and polishing finish for each part. Therefore, in the thrust needle bearing in which the parts are formed by processing that causes such a roughness of accuracy, noise is likely to be generated depending on the use environment, and the problem may be manifested in an application in which the quiet environment is important. There is.

  In other words, as described above, the roller cuts the wire rod and finishes it by the barrel process, so that in the barrel process, the roller is polished and its shape is deteriorated. Specifically, for example, after cutting the wire, even in the polishing after the heat treatment, even if the bus surface shape and roundness of the rolling surface are ensured, a polishing process is performed through the subsequent barrel process to roughen the grinding surface. When the extreme surface layer is cut, the roller busbar shape becomes an arc shape along with the barrel shape, and the roundness also deteriorates. When the axial shape of the roller and the roundness shape of the rolling surface of the roller are affected and the acoustic characteristics are deteriorated, the user may feel uncomfortable when a quiet environment is required.

  Here, Patent Document 2 describes a technique for preventing abnormal noise in a bearing. The abnormal noise of the bearing according to this conventional example is generated by biting the wear powder generated by the wear of the bearing into the bearing race, and is a secondary abnormal noise. Therefore, the technology for preventing such abnormal noise cannot solve the above-mentioned problem that may occur, for example, from a new article.

  On the other hand, Patent Document 3 also describes a technique for preventing abnormal noise in a bearing. This abnormal noise due to the conventional example is assumed to be caused by retained austenite. This technology is effective against the abnormal noise caused by the deformation of the retained austenite due to the use of bearings and the deformation of the surface of the rolling element due to the decrease in residual compressive stress. It is a countermeasure. Therefore, a sufficient effect cannot be obtained against abnormal noise generated immediately after installation due to the shape of the bearing as in this case.

  The present invention has been invented in view of the problems in the prior art, and a thrust needle bearing roller capable of eliminating acoustic problems by making the accuracy of the roller within the intended range and the roller It is an object of the present invention to provide a used thrust needle bearing.

The thrust needle bearing roller of the present invention is
In a roller used for a thrust needle bearing comprising a plurality of rollers and a cage for holding the rollers,
The roller is crowned by barrel processing from at least one end surface to the rolling surface, and when the cross section is taken in the radial direction, the roundness of the rolling surface is 1.5 μm or less, and the axis line When a cross section is taken in the direction, a straight portion parallel to the axis is included.

  As a result of analyzing the conventional roller having poor acoustic characteristics, the present inventors have found that when the cross section is taken in the axial direction of the roller, there is no straight line in the generatrix of the rolling surface of the roller, and a gentle arc shape is obtained. Focused on that. That is, the rolling surface of the roller is not a complete cylindrical surface, but has a shape that is reduced in diameter toward both ends. In other words, for example, in the barrel process for processing the crowning, too much processing is performed. Therefore, it is thought that it is such a shape, and this leads to deteriorating roundness. For this reason, it was discovered that the rolling of the rollers becomes unstable and noise is likely to occur.

  Based on this finding, in the thrust needle roller of the present invention, when the crowning is performed from at least one end surface to the rolling surface, the roundness of the rolling surface is 1 when the cross section is taken in the radial direction. When the cross section is 0.5 μm or less and the cross section is taken in the axial direction, the straight part parallel to the axial line is included, so that the rolling of the roller can be stabilized and the noise can be kept low by adjusting the roundness. I found out that I can do it. Furthermore, as a result of earnest research, the present inventors can form a roller whose roundness of the rolling surface is 1.5 μm or less by changing the processing time, processing method, etc. in the barrel process. I found what I could do.

  The linear portion preferably has a length of 15% or more and 80% or less of the total length of the roller. Here, the “straight line portion” means a parallel line close to the axial line on the 0.5 μm axis side toward the center line with respect to an axial tangent line based on the outermost diameter when taking a cross section in the axial direction of the roller. It shall mean the part of the outer shape included in the range between two points that are intersections of the busbar shape.

  The crowning of the roller is such that the distance in the direction perpendicular to the axis of the phantom line extending from the straight line portion and the generatrix shape is 5 μm or less at a position of 0.8 mm from the end surface of the roller toward the center. Is preferably set.

  It is preferable that the straight portion extends to a range within 1 mm from both ends of the roller.

  If the crowning of the roller is formed by barrel processing, the effect on the roundness of the roller is great, so the effect of the present invention is high. In particular, in the case of barrel processing, the roundness near the boundary between the crowning and the rolling surface tends to deteriorate. Therefore, when the thrust needle bearing receives a large load, it is preferable that the crowning is formed by another polishing process such as a superfinishing process (superfinishing process).

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of a compressor of a car air conditioner in which a needle bearing according to the present embodiment is incorporated, and FIG. 2 is a view of the configuration of FIG. 1 viewed in the II direction.

  In FIG. 1, a housing 6 constituting the compressor 1 includes a central short cylindrical body 7 sandwiched between a head case 8 and a swash plate case 9 from both sides in the axial direction (left-right direction in FIG. 1). It is united by coupling bolts (not shown). Inside the head case 8, low-pressure chambers 10 and 10 and a high-pressure chamber 11 are provided. Note that not only the inside of the high pressure chamber 11 but also the inside of the low pressure chambers 10 and 10 are positive. A flat partition plate 12 is sandwiched between the main body 7 and the head case 8. The low-pressure chambers 10 and 10 represented as being divided into a plurality of parts in FIG. 1 communicate with each other and communicate with a single suction port 13 (FIG. 2) provided on the outer surface of the head case 8. . The high pressure chamber 11 communicates with a discharge port (not shown) provided in the head case 8. The suction port 13 communicates with the outlet of an evaporator (not shown), and the discharge port (not shown) communicates with the inlet of a condenser (not shown).

  A shaft 14 is rotatably supported in the housing 6 in a state of being spanned between the main body 7 and the swash plate case 9. More specifically, both ends of the shaft 14 are rotatably supported with respect to the main body 7 and the swash plate case 9 by a pair of radial needle bearings 15A and 15B, and a pair of thrust needle bearings 16A and 16B. Thus, the thrust load applied to the shaft 14 can be supported freely.

  The thrust needle bearing 16A according to the present embodiment includes a plurality of rollers 16a, race rings 16b and 16c that clamp the rollers 16a in the axial direction (left and right direction in FIG. 1), and a cage 16d that holds the rollers 16a. doing. Furthermore, the thrust needle bearing 16B according to the present embodiment includes a plurality of rollers 16e, raceways 16f and 16g that sandwich the rollers 16e in the axial direction (left and right in FIG. 1), and a cage 16h that holds the rollers 16e. have.

  The radial needle bearing 15A includes a plurality of rollers 15a, an outer ring (orbital ring) 15b, and a cage 15c that holds the rollers 15a. The radial needle bearing 15B includes a plurality of rollers 15d, an outer ring (track ring) 15e, and a cage 15f that holds the rollers 15d.

  The thrust needle bearing 16A is provided via a disc spring 18 between a part of the main body 7 and a step portion 17 formed at one end portion (right end side in FIG. 1) of the shaft 14. The thrust needle bearing 16 </ b> B is disposed between the disc portion 19 and the swash plate case 9 that are fitted and fixed to the outer peripheral surface of the intermediate portion of the shaft 14. A plurality of (for example, six in the example shown in the figure in the circumferential direction) cylinder holes 20, 20 are formed in the periphery of the shaft 14 inside the main body 7 constituting the housing 6. Sliding portions 22, 22 provided in the front half (right half in FIG. 1) of the pistons 21, 21 are respectively provided inside the plurality of cylinder holes 20, 20 formed in the main body 7 in this manner. It is fitted so that it can be displaced in the direction.

  Here, a space provided between the bottom surfaces of the cylinder holes 20 and 20 and the tip surfaces (right end surfaces in FIG. 1) of the pistons 21 and 21 is referred to as a compression chamber 23. The space existing inside the swash plate case 9 is a swash plate chamber 24. A swash plate 25 is fixed at a predetermined inclination angle with respect to the shaft 14 at a portion located in the swash plate chamber 24 on the outer peripheral surface of the intermediate portion of the shaft 14, and the swash plate 25 rotates together with the shaft 14. I try to do it. A plurality of locations in the circumferential direction of the swash plate 25 and the pistons 21 and 21 are connected by a pair of sliding shoes 26 and 26, respectively. For this reason, the inner side surfaces (surfaces facing each other) of these sliding shoes 26 and 26 are flat surfaces so as to be in sliding contact with portions on both side surfaces of the swash plate 25 that are also flat surfaces. Further, the outer side surfaces of these sliding shoes 26, 26 (side surfaces opposite to the mating sliding shoe 26) are spherical convex surfaces. Further, the outer surfaces of the sliding shoes 26 and 26 are positioned on a single spherical surface with the inner surface thereof being in contact with both side surfaces of the swash plate 25. On the other hand, a driving force transmission mechanism is constructed with sliding shoes 26 and 26 and a swash plate 25 at the base end of each piston 21 and 21 (the end far from the partition plate 12 and the left end in FIG. 1). The connecting portions 27 and 27 are formed integrally with the pistons 21 and 21, respectively. The connecting portions 27 and 27 are formed with holding portions 28 and 28 for holding the pair of sliding shoes 26 and 26. The holding portions 28 and 28 are formed with spherical concave surfaces that are in close sliding contact with the outer surfaces of the sliding shoes 26 and 26 so as to face each other.

  Further, a pair of guide surfaces (not shown) for each piston 21, 21 is provided on the part of the inner peripheral surface of the main body 7 that is aligned with the outer end of each connecting portion 27, 27. They are spaced apart in the circumferential direction. The outer end portions of the connecting portions 27 and 27 are guided by the guide surfaces, and can only be displaced in the axial direction of the pistons 21 and 21 (left and right direction in FIG. 1). Therefore, the pistons 21 and 21 are also prevented from rotating around the central axis of the pistons 21 and 21 in the cylinder holes 20 and 20 due to the rotation of the swash plate 25, and can only be displaced in the axial direction (non-rotatable). ). As a result, the connecting portions 27 and 27 push and pull the pistons 21 and 21 in the axial direction as the swash plate 25 is oscillated and displaced by the rotation of the shaft 14. , 20 to reciprocate in the axial direction.

  On the other hand, in order to partition the low-pressure chamber 10 and the high-pressure chamber 11 from the cylinder holes 20, 20, the partition plate 12 sandwiched between the abutting portions of the main body 7 and the head case 8 includes the low-pressure chamber 10 and the cylinder holes 20. , 20 and the discharge holes 30, 30 communicating with the high-pressure chamber 11 and the cylinder holes 20, 20 are formed in a state of penetrating in the axial direction. Accordingly, the opening on the cylinder hole 20, 20 side at one end (the left end in FIG. 1) of each suction hole 29, 29 and each discharge hole 30, 30 is opposed to the tip surface of each piston 21, 21. In addition, a reed valve type suction that allows refrigerant gas to flow only from the low-pressure chamber 10 toward each cylinder hole 20, 20 in a part of each cylinder hole 20, 20 facing one end of each suction hole 29, 29. Valves 31 are provided. Further, in the high-pressure chamber 11, the refrigerant gas is allowed to flow only from the cylinder holes 20, 20 toward the high-pressure chamber 11 in the portion facing the other end (right end in FIG. 1) opening of each discharge hole 30, 30. A reed valve type discharge valve 32 is provided. The discharge valve 32 is provided with a stopper 33 that restricts displacement in a direction away from the discharge holes 30.

  The shaft 14 of the compressor 1 configured as described above is rotationally driven via an endless belt 42 by a vehicle engine (not shown). For this reason, in the case of the illustrated example, the driven pulley 35 around the support cylinder portion 34 provided in the center of the outer surface (left side surface in FIG. 1) of the swash plate case 9 constituting the housing 6 is connected to a double row radial ball. The bearing 36 is rotatably supported. The driven pulley 35 has a U-shaped cross section and is formed in an annular shape as a whole. A solenoid 37 fixed to the outer surface of the swash plate case 9 is disposed in the internal space of the driven pulley 35. On the other hand, a mounting bracket 38 is fixed to a portion protruding from the support cylinder portion 34 at the end of the shaft 14, and an annular plate 39 made of a magnetic material is supported around the mounting bracket 38 via a plate spring 40. doing. When the solenoid 37 is not energized, the annular plate 39 is separated from the driven pulley 35 by the elastic force of the leaf spring 40 as shown in the figure. However, when the solenoid 37 is energized, the annular plate 39 is attracted toward the driven pulley 35. The rotational force from the driven pulley 35 to the shaft 14 can be freely transmitted. That is, the solenoid 37, the annular plate 39, and the leaf spring 40 constitute an electromagnetic clutch 41 for engaging and disengaging the driven pulley 35 and the shaft 14. Further, an endless belt 42 is stretched between a driving pulley and a driven pulley 35 fixed to an end of a crankshaft (not shown) of a vehicle engine.

  The operation of the compressor of the car air conditioner according to the present embodiment will be described. When the car air conditioner is operated to cool or dehumidify the passenger compartment, the electromagnetic clutch 41 is operated to engage the driven pulley 35 and the shaft 14, thereby causing the vehicle to pass through the endless belt 42. The power of the engine is transmitted to the shaft 14 and is driven to rotate. As a result, the swash plate 25 rotates to reciprocate the sliding portions 22 and 22 constituting the plurality of pistons 21 and 21 in the cylinder holes 20 and 20, respectively. As the sliding portions 22 and 22 reciprocate, the refrigerant gas sucked from the suction port 13 is sucked into the compression chamber 23 from the low pressure chambers 10 and 10 through the suction holes 29 and 29. . The refrigerant gas is compressed in each of the compression chambers 23 and then sent to the high-pressure chamber 11 through the discharge holes 30 and 30 and is discharged from the discharge port. After that, the high-temperature and high-pressure refrigerant gas is cooled by a condenser to become a liquid refrigerant, and then rapidly expanded to flow into the evaporator as a low-temperature and low-pressure mist refrigerant, where the air supplied to the passenger compartment After cooling, the refrigerant gas is sucked into the compressor.

  FIG. 3 is a diagram in which the bus bar shape of the roller formed by the processing method of the prior art is measured, and FIG. 4 is a diagram in which the bus bar shape of the roller formed by the processing method of the present embodiment is measured. 2 times and 20 times wide. 3 and 4, the crowning C (arc-shaped part) is formed at both ends. In addition, compared with the conventional processing method, in the processing method of this invention, the processing time and processing content of barrel processing are changed.

  As shown in FIG. 3, in the case of the roller formed by the processing method of the prior art, the bus bar shape of the outer peripheral surface gradually approaches the axial line toward both ends, and the axial direction length of the central straight portion L1 is 0.5 mm. It has become. In an extreme example, the straight portion L1 may be 0 mm. Since the total length of the roller is 4.5 mm, the straight portion L1 is 11% or less of the total length of the roller.

  On the other hand, in the case of a roller formed by the processing method of the present embodiment, as shown in FIG. At the center, the range of the straight line portion L2 is widened, and its axial length is 2.0 mm. Similarly, since the total length of the roller is 4.5 mm, the straight portion L2 is 44% of the total length of the roller.

  In the example shown in FIG. 3, the crowning of the roller is perpendicular to the axis of the imaginary line obtained by extending the straight line portion of the bus bar shape and the bus bar shape at a position (GP) of 0.8 mm from the roller end face toward the center. The direction distance (Δ) is set to be 6 μm. On the other hand, in the example shown in FIG. 4, the crowning of the roller is made up of an imaginary line obtained by extending a straight line portion of the bus bar shape and a bus bar shape at a position (GP) of 0.8 mm from the roller end face toward the center. The distance (Δ) in the direction orthogonal to the axis is set to 4 μm. In addition, it is preferable that the straight part of the bus bar shape extends to a range within 1 mm from both ends of the roller.

  FIG. 5 is a diagram in which the roundness of a rolling surface (within the range of the straight line portion L1 in FIG. 3) of a roller formed by a conventional processing method is measured, and FIG. 6 is a processing method according to the present embodiment. FIG. 5 is a diagram obtained by measuring the roundness of the rolling surface (within the range of the straight line portion L2 in FIG. 4) of the roller formed by the above.

  As shown in FIG. 5, in the case of a roller formed by a conventional processing method, the roundness of the rolling surface was 2.0 μm. In contrast, in the case of the roller formed by the processing method of the present embodiment, as shown in FIG. 6, the roundness of the rolling surface was 0.9 μm.

The present inventors made a roller for a thrust needle bearing in which the roundness of the roller and the length of the straight line portion were changed, and judged whether the sound generated by the bearing was good or bad by the tester's hearing under the following test conditions. An acoustic test was performed. The test results are shown in Table 1.
Test conditions (1) Bearing used: Thrust needle bearing with inner diameter φ50 x outer diameter φ70 (mm) (2) Roller: outer diameter φ3 x length 4.5 (mm)
(3) Rotation speed: Sweep between 1000 and 5000 min ⁻¹ (4) Axial load: Sweep in steps between 1000 and 7000 N

  In the test results of Table 1, “bad” means that the acoustic characteristics are bad, “good” means that the acoustic characteristics are good, and “slightly bad” means “bad” and “ It means the middle of “good” and can be used depending on the conditions. According to the test results, it can be seen that even if the straight portion is secured, if the roundness of the roller is 1.7 μm or more, the acoustic characteristics are poor (noise is large). However, it can be seen that if the roundness of the roller is 1.5 μm or less, the acoustic characteristics are improved. Further, it can be seen that if the length of the linear portion of the roller is 0.5 mm or less, the acoustic characteristics are poor. However, it can be seen that if the length of the linear portion of the roller is 0.8 mm or more, the acoustic characteristics are improved.

  Considering the above test results, if the length of the straight line portion in the roller bus bar shape is 15% or more of the total length of the roller, an effect of improving the acoustic characteristics can be obtained. If the length is shorter than 15%, the roller rolling surface is obtained. As a result, the roundness becomes worse, and the degree of improvement is considered to be small. In addition, when the straight portion exceeds 80%, the degree of effect on the acoustic characteristics is large. However, as a result of securing the length of the straight portion, the amount of crowning is reduced, so that the roller against the inclination of the bearing. Edge load is likely to occur, and depending on use conditions, damage such as flaking may be caused. Therefore, it is desirable that the linear portion of the roller is 80% or less of the total length. When the length of the straight portion is about 30 to 60% of the total length of the roller, a higher dimensional balance can be obtained.

  FIG. 7 is a cross-sectional view of a manual transmission (always meshing transmission) in which the needle bearing according to the present embodiment is incorporated. In FIG. 7, any of the gears G1 to G3 disposed on the main shaft 101 is engaged with any of the gears GU1 to GU4 of the gear unit GU disposed on the countershaft 102 so as to be able to transmit power, thereby reducing the speed. Has come to be realized. The thrust needle bearing 116 according to the present embodiment is disposed between the case 103 and the gear unit GU and receives a thrust force.

  FIG. 8 is a cross-sectional view of an automatic transmission for a vehicle including a needle bearing according to the present embodiment. In FIG. 8, thrust needle bearings 201 to 210 are arranged to receive the thrust force of each element. As described above, the thrust needle bearing of the present invention can be used not only for a car cooler compressor but also for various machines in addition to a stepped transmission or a continuously variable transmission for an automobile.

  The present invention has been described above with reference to the embodiments. However, the present invention is not limited to the above-described embodiments, and can of course be changed or improved within the scope of the invention.

It is sectional drawing of the compressor of the car air conditioner in which the needle bearing concerning this Embodiment was integrated. It is the figure which looked at the structure of FIG. 1 in the II direction. It is the figure which measured the bus-bar shape of the roller formed with the processing method of a prior art. It is the figure which measured the bus-bar shape of the roller formed with the processing method of this Embodiment. It is the figure which measured the roundness of the rolling surface of the roller formed with the processing method of the prior art. It is the figure which measured the roundness of the rolling surface of the roller formed with the processing method of this Embodiment. It is sectional drawing of the manual transmission (always meshing type transmission) with which the needle bearing concerning this Embodiment was integrated. It is sectional drawing of the automatic transmission of the vehicle containing the needle bearing concerning this Embodiment.

Explanation of symbols

1 Car Air Conditioner Compressor 6 Housing 14 Shaft 15A, 15B Radial Needle Bearing 16A, 16B, 116, 201-210 Thrust Needle Bearing

Claims (6)

In a roller used for a thrust needle bearing comprising a plurality of rollers and a cage for holding the rollers,
The roller is crowned from at least one end surface to the rolling surface, and when the cross section is taken in the radial direction, the roundness of the rolling surface is 1.5 μm or less and the cross section in the axial direction. A thrust needle bearing roller comprising a straight portion parallel to the axis when taken.   The thrust needle bearing roller according to claim 1, wherein the straight portion has a length of 15% or more and 80% or less of a total length of the roller.   The crowning of the roller is such that the distance in the direction perpendicular to the axis of the phantom line extending from the straight line portion and the generatrix shape is 5 μm or less at a position of 0.8 mm from the end surface of the roller toward the center. The thrust needle bearing roller according to claim 1, wherein the roller is a thrust needle bearing roller.   The thrust needle bearing roller according to any one of claims 1 to 3, wherein the straight portion extends to a range within 1 mm from both ends of the roller.   The thrust needle bearing roller according to any one of claims 1 to 4, wherein the crowning of the roller is formed by barrel processing. A thrust needle bearing using the roller according to any one of claims 1 to 5.

Images