JP2007327517A - Thrust roller bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thrust roller bearing capable of realizing a long life. <P>SOLUTION: The thrust roller bearing has a plurality of rollers 11, a plurality of pockets 22 for holding the plurality of rollers and a disk-like retainer 21 of which collar part 26a at an outer circumference side is bent in a rotation shaft direction. An inner circumference side face of the collar part 26a at the outer circumference side forms a wall face 27a at an outer circumference side of the pocket 22 which is an ironed face. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a thrust roller bearing, and more particularly to a thrust roller bearing used in a lean lubrication environment.

  Thrust roller bearings used in car air-conditioning compressors, automatic transmissions, manual transmissions, and hybrid vehicles are used in harsh environments such as high-speed rotation and lean lubrication due to recent demands for fuel saving, downsizing, and higher output. The characteristics that can withstand use even under are required. Thrust roller bearings that can withstand harsh usage environments are disclosed in Japanese Patent Application Laid-Open No. 2003-83333 (Patent Document 1), Japanese Patent Application Laid-Open No. 2005-164023 (Patent Document 2), and Japanese Patent Application Laid-Open No. 2004-301195 (Patent Document 3). Is disclosed.

Here, the manufacturing method of the cage included in the thrust roller bearing disclosed in Patent Document 3 will be briefly described. First, pocket punching is performed so as to form a pocket for holding the roller. Thereafter, the inner diameter side is bent outward to form the inner diameter side flange portion. Further, the outer diameter side flange portion extending to the outer diameter side end portion of the pocket is formed by bending in the reverse direction on the inner diameter side of the outer diameter side end portion of the pocket. In this way, the cage is manufactured.
JP 2003-83333 A (paragraph numbers 0016 to 0022, FIGS. 1 to 3) Japanese Patent Laying-Open No. 2005-164023 (paragraph numbers 0019 to 0022, FIGS. 1 and 2) JP 2004-301195 A (paragraph numbers 0021, 0024, FIG. 3, FIG. 4 (a), FIG. 4 (b))

  According to Patent Document 1 and Patent Document 2, the thrust roller bearing has a roller whose end surface is a curved surface and a cage. By doing so, the sliding resistance between the outer peripheral end face of the roller and the outer peripheral wall surface of the pocket is reduced, and the wear of the outer peripheral wall surface of the pocket is reduced.

  According to Patent Literature 3, the wall surface on the outer peripheral side of the pocket is constituted by a collar portion bent in the direction of the rotation axis. By doing so, the area of the wall surface on the outer peripheral side of the pocket is widened, the contact surface pressure received from the end surface on the outer peripheral side of the roller is reduced, and wear on the wall surface on the outer peripheral side of the pocket is reduced.

  However, among the cages shown in Patent Documents 1 to 3, the wall surface on the outer peripheral side of the pocket is the surface of the iron plate. The surface of the iron plate is a rough surface, and its surface roughness is poor. Even if the wall surface on the outer peripheral side of the pocket is used as a punched surface, the surface roughness is poor. When the outer peripheral end face of the pocket having such poor surface roughness comes into contact with the outer peripheral end face, drilling wear occurs. In particular, the tendency is remarkable in the above severe use environment. If it does so, the wall surface of the outer peripheral side of a pocket will be worn greatly, and the long life of a thrust roller bearing cannot be aimed at.

  Further, when the roller has a small diameter, it is difficult to appropriately contact the end face of the roller and the wall surface on the outer peripheral side of the pocket by the above-described manufacturing method.

  An object of the present invention is to provide a thrust roller bearing capable of realizing a long life.

  A thrust roller bearing according to the present invention includes a plurality of rollers and a disk-shaped cage having a plurality of pockets for holding the plurality of rollers and having a flange on the outer peripheral side bent in the direction of the rotation axis. The inner peripheral surface of the outer flange portion forms a wall surface on the outer peripheral side of the pocket, and the outer peripheral wall surface of the pocket is an ironed surface.

  With this configuration, when the roller rolls, when the end surface on the outer periphery side of the roller comes into contact with the wall surface on the outer periphery side of the pocket, the end surface on the outer peripheral side of the ironed surface comes into contact. become. Since the ironed surface is smooth and has a good surface roughness, drilling wear can be suppressed. Moreover, since the wall surface on the outer peripheral side of the pocket is formed by the flange portion on the outer peripheral side bent in the direction of the rotation axis, the area can be increased and the PV value can be reduced. Therefore, the wear on the wall surface on the outer peripheral side of the pocket can be suppressed, and the long life of the thrust roller bearing can be realized.

  Preferably, the length of the play amount of the roller in the rotation axis direction is shorter than the length of the ironed surface in the rotation axis direction. With this configuration, even if the roller moves in the range of the length of the clearance in the direction of the rotation axis, the end surface of the roller and the ironed surface come into contact with each other. If it does so, the end surface of a roller can be made to contact | abut to the surface ironed and processed reliably.

  More preferably, the ironing amount of the ironed surface is 20% or less of the plate thickness of the cage. The ironing process is performed by scraping the plate thickness of the cage. Here, if the amount of ironing, that is, the amount of scraping increases, the plate thickness becomes thin, and the strength of the wall surface on the outer peripheral side of the pocket may be insufficient. Therefore, the strength of the wall surface on the outer peripheral side of the pocket can be maintained by setting the ironing amount to 20% or less of the plate thickness of the cage.

  More preferably, the surface roughness Ra of the ironed surface is 2 μm or less. With such surface roughness, drilling wear can be suppressed and wear on the outer peripheral wall of the pocket can be reduced. Here, the surface roughness Ra refers to the arithmetic average roughness.

  More preferably, the end surface on the outer peripheral side of the roller has a curved surface that bulges in the direction of the rolling axis. By carrying out like this, since it can be made to contact in a point with small peripheral speed, PV value can be made smaller and abrasion resistance can be improved.

  According to this invention, at the time of rolling of the roller, when the end surface on the outer peripheral side of the roller contacts the wall surface on the outer peripheral side of the pocket, the end surface on the outer peripheral side of the ironed surface comes into contact. . Since the ironed surface is smooth and has a good surface roughness, drilling wear can be suppressed. Moreover, since the wall surface on the outer peripheral side of the pocket is formed by the flange portion on the outer peripheral side bent in the direction of the rotation axis, the area can be increased and the PV value can be reduced. Therefore, the wear on the wall surface on the outer peripheral side of the pocket can be suppressed, and the long life of the thrust roller bearing can be realized.

  Embodiments of the present invention will be described below with reference to the drawings. First, a thrust roller bearing according to an embodiment of the present invention will be described. FIG. 2 is a view of a thrust roller bearing according to an embodiment of the present invention viewed from the axial direction. 3 is a cross-sectional view of the thrust roller bearing shown in FIG. 2 taken along line III-O-III in FIG. FIG. 4 is an enlarged view of a portion indicated by IV in FIG. FIG. 1 is an enlarged view of a portion indicated by I in FIG.

  1 to 4, the thrust roller bearing 31 includes a plurality of rollers 11 and a cage 21 that holds the plurality of rollers 11. The end surface 12 of the roller 11 is an end surface having an A end surface, that is, a radially central portion that bulges in the rolling axis direction, and whose cross section is configured with a single curvature.

  The cage 21 is composed of a disk-shaped member, and couples the pair of annular portions 23 a and 23 b so as to form a pair of annular portions 23 a and 23 b and a pocket 22 for holding the roller 11. A plurality of pillars 24. A plurality of pockets 22 are provided radially about the rotation axis. Each pocket 22 is provided with a roller stopper 25 for preventing the roller 11 from falling off. The pocket 22 is provided with a play that allows the rollers 11 to move. The roller 11 can move in the rotation axis direction, the radial direction, and the circumferential direction within the allowable range in the pocket 22, and the amount of play that the roller 11 can move is determined by the roller stopper 25 or the like.

  Central portions in the radial direction of the plurality of column portions 24 are bent so as to be folded back in the rotation axis direction. Further, the outer peripheral side and inner peripheral side flanges 26a and 26b of the cage 21 are also bent so as to be folded back in the rotation axis direction. The cross sections of the flange portions 26a and 26b and the column portion 24 are substantially W-shaped (see FIG. 3). On the wall surface 27 a on the outer peripheral side of the pocket 22, an outer flange portion 26 a that is bent in the rotation axis direction is located. In other words, the outer flange portion 26 a bent in the direction of the rotation axis forms a wall surface 27 a on the outer periphery side of the pocket 22.

  Here, the outer peripheral wall surface 27a of the pocket 22 is a surface that has been ironed. In the ironing process, for example, a male ironing jig having a ironing arm and a female ironing jig having a ironing groove are used, and the cage 21 is set on the female ironing jig, and the male die is set in the vertical direction. This is done by pushing the ironing jig forward and scraping the plate thickness of the flange 26a bent in the direction of the rotation axis. The wall surface 27a on the outer peripheral side of the pocket 22 that is the ironed surface is smoother and has a better surface roughness than the punched surface or the surface of the cage 21. Note that the inner wall surface 27b of the pocket 22 is not ironed.

  When the roller 11 rolls, the roller 11 moves to the outer peripheral side by centrifugal force or the like. If it does so, the end surface 12 of the outer peripheral side of the roller 11 and the wall surface 27a of the outer peripheral side of the pocket 22 will contact | abut.

  FIG. 5 is a view showing a state in which the outer peripheral end surface 12 of the roller 11 is in contact with the outer peripheral side wall surface 27 a of the pocket 22, and corresponds to FIG. 4. FIG. 6 is an enlarged sectional view of the thrust roller bearing 31 in this case, and corresponds to FIG. With reference to FIGS. 5 and 6, the outer peripheral end surface 12 of the roller 11 contacts the outer peripheral wall surface 27 a of the pocket 22. Specifically, the portion of the end surface 12 of the roller 11 that bulges most in the rolling axis direction and the wall surface 27a on the outer peripheral side of the pocket 22 abuts in the vicinity of the central portion in the rotational axis direction and the radial direction. .

  Since the wall surface 27a on the outer peripheral side of the pocket 22 is a surface subjected to ironing, the surface roughness is good. If it does so, even if the end surface 12 of the roller 11 contact | abuts, the drilling wear of the wall surface 27a of the outer peripheral side of the pocket 22 can be suppressed. In this case, since the end surface 12 is an A end surface and has a curved surface, it can be contacted at a point with a small peripheral speed. Moreover, since the collar part 26a bent in the rotation axis direction is used as the outer wall surface 27a, an area equal to or greater than the thickness of the cage 21 can be secured. Then, since the area can be increased, the PV value which is a value obtained by multiplying the contact surface pressure P and the sliding speed V can be lowered. In particular, in the case of the F end face, that is, a flat end face, the effect is remarkable.

  Therefore, the pocket 22 can stably hold the roller 11 for a long period of time, and the thrust roller bearing 31 including such a cage 21 can realize a long life.

  In addition, the length of the play amount of the roller 11 in the rotation axis direction is preferably shorter than the length C in the rotation axis direction of the ironed surface. As described above, the pocket 22 is provided with play. By doing so, when the roller 11 rolls, the roller 11 moves within the range of the amount of play in the rotation axis direction. However, the end surface 12 on the outer peripheral side of the roller 11 and the ironing surface forming the wall surface 27a on the outer peripheral side of the pocket 22 can be reliably brought into contact with each other.

  Here, the manufacturing method of the above-described cage 21 will be described. FIG. 7A to FIG. 7C are flowcharts showing typical steps in the method for manufacturing the cage 21.

  With reference to FIGS. 7A to 7C, first, the shape of the cage 21 is punched out from an iron plate, which is a constituent material of the cage 21, by a punch or the like (FIG. 7A). Next, the outer peripheral side flange part 26a, the inner diameter side flange part 26b, and the central part of the column part 24 are bent by a press or the like so as to be folded back in the direction of the rotation axis (FIG. 7B). Then, pocketing is performed while squeezing so that the bent outer flange 26a becomes the outer wall 27a of the pocket 22 (FIG. 7C). In this way, each pocket 22 included in the cage 21 is formed, and the cage 21 is manufactured.

  In such a manufacturing method, since the central portion of the column portion 24 and the flange portions 26a and 26b are folded back in the rotation axis direction before the pocket removing step, the pocket can be formed with high accuracy. it can. In particular, even when the roller 11 has a small diameter, it is possible to ensure the outer peripheral surface of the cage for contact with the roller end surface.

  The ironing amount of the pocket 22 is preferably 20% or less of the plate thickness of the cage 21. That is, in FIG. 1, when the plate thickness of the cage 21 is A and the ironing amount of the wall surface 27a of the pocket 22 is B, the ironing amount B is 20% or less of the plate thickness A. As the amount of ironing increases, the plate thickness decreases. If it does so, there exists a possibility that the wall surface 27a of the outer peripheral side of the pocket 22 may become insufficient in strength. Therefore, the strength of the wall surface 27a can be maintained by setting the ironing amount B to 20% or less of the plate thickness A.

  The surface roughness Ra of the ironing surface is preferably 2 μm or less. If the surface roughness Ra is within such a range, wear of the end surface 12 of the roller 11 and the wall surface 27a on the outer peripheral side of the pocket 22 can be reduced.

  In the above embodiment, only the outer peripheral wall surface of the pocket is a surface formed by ironing. However, the present invention is not limited to this, and the inner peripheral wall surface of the pocket is also formed by ironing. It may also be a surface. By doing so, wear due to contact between the inner peripheral wall surface of the pocket and the inner peripheral end surface of the roller can be reduced, and a longer life can be achieved.

  In the above embodiment, the outer peripheral side and inner peripheral side ridges are folded so as to be folded back. However, the present invention is not limited to this, and the folding may be performed in one direction without folding back.

  In the above embodiment, the end face of the roller is the A end face. However, the present invention is not limited to this, and the end face of the F is composed of a plurality of curved faces having different curvatures. You may use the roller which has R end surface.

  As mentioned above, although embodiment of this invention was described with reference to drawings, this invention is not limited to the thing of embodiment shown in figure. Various modifications and variations can be made to the illustrated embodiment within the same range or equivalent range as the present invention.

  The thrust roller bearing according to the present invention has good wear resistance and can achieve a long life in a lean lubrication environment, so it can be effectively used in a car air conditioner compressor, an automatic transmission, a manual transmission, and a hybrid vehicle. Is done.

It is an expanded sectional view near the wall surface of the outer peripheral side of a pocket among thrust roller bearings according to an embodiment of the present invention. It is the figure which looked at the thrust roller bearing which concerns on one Embodiment of this invention from the axial direction. It is sectional drawing at the time of cut | disconnecting the thrust roller bearing shown in FIG. 2 by the line III-O-III in FIG. It is an enlarged view of the part shown by IV in FIG. 2 among the thrust roller bearings shown in FIG. It is the enlarged view which looked at the state which the end surface of the outer peripheral side of a roller and the wall surface of the outer peripheral side of a pocket contacted from the axial direction. It is an expanded sectional view which shows the state which the end surface of the outer peripheral side of a roller and the wall surface of the outer peripheral side of a pocket contact | abutted. It is a flowchart which shows a typical process among the manufacturing processes of the holder | retainer contained in the thrust roller bearing which concerns on one Embodiment of this invention.

Explanation of symbols

  11 Rollers, 12 End faces, 21 Cages, 22 Pockets, 23a, 23b Annular parts, 24 Pillar parts, 25 Roller stoppers, 26a, 26b Rims, 27a, 27b Wall surfaces, 31 Thrust roller bearings.

Claims (5)

With multiple times,
A plurality of pockets for holding the plurality of rollers, and a disc-shaped cage in which a flange portion on the outer peripheral side is bent in the rotation axis direction;
The inner peripheral surface of the outer peripheral flange portion forms the outer peripheral wall surface of the pocket,
A thrust roller bearing, wherein the wall surface on the outer peripheral side of the pocket is an ironed surface. 2. The thrust roller bearing according to claim 1, wherein a length of a clearance amount of the roller in a rotation axis direction is shorter than a length of the ironed surface in the rotation axis direction. The thrust roller bearing according to claim 1 or 2, wherein an ironing amount of the ironed surface is 20% or less of a plate thickness of the cage. The thrust roller bearing according to claim 1, wherein the surface roughness Ra of the ironed surface is 2 μm or less. The thrust roller bearing according to any one of claims 1 to 4, wherein an end surface on an outer peripheral side of the roller has a curved surface that bulges in a rolling axis direction.

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