JP2006118696A - Thrust roller bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thrust roller bearing capable of preventing abnormal wear caused by contact of a cage outer diameter side end of a roller to an outer diameter side end face of a pocket part. <P>SOLUTION: The thrust roller bearing 10 has the roller 13, and a cage 14 provided with the pocket part 15 holding the roller 13. A groove 16 communicated with the pocket part 15 is formed on a surface of the cage 14. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a thrust roller bearing used for a rotation support portion of, for example, an automatic transmission of a car or a compressor for a car air conditioner.

  Conventionally, a thrust roller bearing is mounted on a rotation support portion of an automatic transmission of a car or a compressor for a car air conditioner so as to support a load in an axial direction.

  Generally, in the thrust roller bearings 100 and 110, as shown in FIGS. 9 to 11, a plurality of rollers 103 are arranged between the stationary side race ring 102 and the rotation side race ring 101 facing each other in the axial direction. It is arranged to be able to roll in the circumferential direction via 111.

  In the cage 104 shown in FIGS. 9 and 10, for example, a plurality of pocket portions 105 for holding the rollers 103 are formed at substantially equal intervals in the circumferential direction corresponding to the number of the rollers 103 on an annular plate made of resin. In each pocket portion 105, a plurality of rollers 103 are arranged radially with their axes directed in the radial direction of the cage 104.

  Further, the metal cage 111 shown in FIG. 11 is formed into an annular hollow body having a substantially rectangular cross section, for example, by joining two annular metal plates 112 and 113 having a substantially U-shaped cross section by caulking or the like. In the same manner as described above, pocket portions 114 that hold the rollers 103 in a rollable manner are formed at approximately equal intervals in the circumferential direction on both end faces in the axial direction of the annular hollow body.

  By the way, in the thrust roller bearings 100 and 110, the roller 103 rotates in a state where the end portion on the outer diameter side of the roller 103 is pressed against the outer diameter side end surfaces 105a and 114a of the pocket portions 105 and 114 by centrifugal force. Therefore, there is a possibility that abnormal wear occurs on the outer diameter side end surfaces 105a and 114a.

Therefore, in a conventional thrust roller bearing, the shape of the end portion in the axial direction of the roller is defined as a JIS symbol F shape to define accuracy (for example, refer to Patent Document 1), or a hardened layer of 600 Hv or more in a metal cage. By forming (for example, refer to Patent Document 2), abnormal wear is prevented from occurring on the outer diameter side end face of the pocket portion.
JP 2004-156744 A JP 2004-045655 A

  However, in Patent Document 1 and Patent Document 2, the state in which the flow rate of the lubricant flowing into the space on the outer diameter side of the pocket portion of the pocket portion is small, that is, the end portion on the outer diameter side of the roller and the outside of the pocket portion. When the contact with the radial end face becomes the boundary lubrication state, the progress of wear can be delayed, but the abnormal wear itself cannot be prevented.

  The present invention has been made in order to eliminate such inconveniences, and its purpose is to prevent abnormal wear caused by contact of the roller outer diameter side end of the roller with the outer diameter side end surface of the pocket portion. It is an object of the present invention to provide a thrust roller bearing that can be used.

The object of the present invention is achieved by the following configurations.
(1) A thrust roller bearing having a roller and a cage having a pocket portion for holding the roller, and a groove communicating with the pocket portion is formed on a surface of the cage. A featured thrust roller bearing.
(2) The thrust roller bearing according to (1), wherein the cage is made of resin.
(3) The thrust roller bearing according to (2), wherein the cage includes a sliding resistance reducing film at least on an outer diameter side end face of the pocket portion.
(4) The thrust roller bearing according to (3), wherein the sliding resistance reduction film is a diamond-like carbon film.
(5) The thrust roller bearing according to (3), wherein the sliding resistance reduction film is a fluororesin coating film.

  According to the thrust roller bearing of the present invention, since a groove communicating with the pocket portion is formed on the surface of the cage, the groove functions as a lubricant supply groove to the pocket portion, and the cage outer diameter of the roller Side surface and the outer diameter side end surface of the pocket portion can secure a sufficient amount of lubricant, which causes abnormal wear on the outer diameter side end surface of the pocket portion due to centrifugal force. It can be prevented from occurring.

  In addition, according to the thrust roller bearing of the present invention, the resin cage is adapted for high-speed rotation. Furthermore, by providing a sliding resistance-reducing film at least on the outer diameter side end face of the pocket part, sufficient hardness and wear resistance can be secured on the outer diameter side end face of the pocket part. Can be prevented.

  Hereinafter, each embodiment of the thrust roller bearing according to the present invention will be described in detail with reference to the drawings.

(First embodiment)
First, with reference to FIG.1 and FIG.2, the thrust roller bearing which is 1st Embodiment of this invention is demonstrated. FIG. 1 is a cross-sectional view of a main part for explaining a thrust roller bearing according to a first embodiment of the present invention, and FIG. 2 is a plan view of a cage incorporated in the thrust roller bearing of FIG.

  As shown in FIGS. 1 and 2, the thrust roller bearing 10 includes a plurality of axially opposed stationary-side bearing rings 12 and a rotating-side bearing ring 11 that are disposed so as to be able to roll in the circumferential direction. It has the roller 13 and the holder | retainer 14 provided with the some pocket part 15 which hold | maintains the some roller 13 each.

  The cage 14 is formed of resin, and a plurality of pocket portions 15 corresponding to the number of rollers 13 are formed in an annular plate material at substantially equal intervals in the circumferential direction. The plurality of rollers 13 are arranged radially in each pocket portion 15 with the axis thereof directed in the radial direction of the cage 14.

  On the surface of the cage 14, a plurality of a pair of curved grooves 16 communicating with the pocket portion 15 are formed corresponding to the number of pocket portions 15 with respect to one pocket portion 15. Each curved groove 16 extends in a radially outward direction from the inner peripheral surface of the cage 14 between the adjacent pocket portions 15, 15, and has a side surface of the pocket portion 15 that faces the rolling surface of the roller 13. They communicate with each other in the vicinity of the outer diameter side.

  As shown in FIG. 3, the cage 14 includes a diamond-like carbon film (DLC film) 17 that is a sliding resistance reducing film in the vicinity of the outer diameter side end face 15 a of the pocket portion 15. The DLC film 17 can be formed at a relatively low temperature by a method such as plasma CVD (Chemical Vapor Deposition), non-equilibrium sputtering, vacuum arc discharge PVD (Physical Vapor Deposition), ion beam formation, ionization deposition, or the like. It is possible to form a film on the outer diameter side end face 15a using carbon-based gas (acetylene, ethylene, methane, ethane, benzene, etc.) or graphite as a target. Further, the DLC film 17 has a very smooth surface as compared with a hard thin film having a polycrystalline structure, and is a film having a small friction coefficient of 0.1 or less. The DLC film 17 has a very high Vickers hardness of about Hv 2000 to 4500, and has very good wear resistance and seizure resistance.

  In addition, as the sliding resistance reducing film, a fluororesin coating film may be formed in the vicinity of the outer diameter side end face 15a of the pocket portion 15 instead of the DLC film. As a method for forming the fluororesin coating film, for example, the surface treatment is performed by subjecting the outer diameter side end face 15a to shot peening or sebber, and then a tetrafluoroethylene using a thermosetting resin such as polyamideimide or epoxy resin as a binder. For example, a coating layer made of molybdenum disulfide can be formed on the outer diameter side end face 15a with a spray gun or the like, and the coating layer is baked to form a fluororesin coating film.

  Further, molybdenum disulfide and ethylene tetrafluoride may be used alone. In addition, providing a metal solid lubricant layer such as Ag or Sn by plating or the like after the base treatment is also beneficial for improving seizure resistance. Furthermore, the synthetic resin used as the binder is not limited to polyamiimide, and other thermosetting resins such as epoxy resins can be used.

  Further, the sliding resistance reducing film only needs to include at least the vicinity of the outer diameter side end face 15a of the pocket portion 15, and may be applied to the entire resin cage 14 as shown in FIG.

  Therefore, in the thrust roller bearing 10 of the present embodiment, the curved groove 16 communicating with the pocket portion 15 is formed on the surface of the cage 14, so that the lubricant flows into the bearing space from the inner peripheral surface of the cage 14. Is guided to the outer diameter side of the pocket portion 15 along the curved groove 16. As a result, the curved groove 16 functions as a lubricant supply groove to the pocket portion 15, and a flow rate sufficient for the contact portion between the end portion 13 a of the roller 13 on the outer diameter side of the cage and the outer diameter side end surface 15 a of the pocket portion 15. The lubricant can be secured. As a result, it is possible to satisfactorily prevent abnormal wear from occurring on the outer diameter side end face 15a of the pocket portion 15 due to the centrifugal force.

Further, in the thrust roller bearing 10 of the present embodiment, the cage made of resin is adapted for high speed rotation. Further, by forming the DLC film 17 at least on the outer diameter side end surface 15a of the pocket portion 15, sufficient hardness and wear resistance can be ensured on the outer diameter side end surface 15a of the pocket portion 15, so that the roller 13 is subjected to centrifugal force. Even if it contacts the outer diameter side end surface 15a of the pocket portion 15 and rotates in that state, abnormal wear and abnormal heat generation of the cage can be avoided more reliably.
Further, as shown in FIG. 4, by applying the DLC film 17 to the entire surface of the cage 14, wear and heat generation due to contact with the raceway and the rotating shaft can be prevented.

(Second Embodiment)
Next, a thrust roller bearing which is a second embodiment of the present invention will be described with reference to FIGS. FIG. 5 is a cross-sectional view of a main part for explaining a thrust roller bearing according to a second embodiment of the present invention, and FIG. 6 is a plan view of a cage incorporated in the thrust roller bearing of FIG. In addition, about the part equivalent to 1st Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted or simplified.

  In the thrust roller bearing 20, as shown in FIGS. 5 and 6, an inclined groove 21 is formed over the region between the adjacent pocket portions 15, 15 on the surface of the cage 14. The inclined groove 21 gradually becomes deeper in the radial direction from the same radial position as the inner diameter side end face of the pocket portion 15 to the vicinity of the same radial position as the outer diameter side end face of the pocket portion 15. Accordingly, the inclined groove 21 is formed so as to communicate with the pocket portion 15 on both side surfaces in the circumferential direction of the pocket portion 15.

  Therefore, in the thrust roller bearing 20 of the present embodiment, by providing the inclined groove 21 communicating with the pocket portion 15 on the surface of the cage 14, a slight oil sump is formed on the radially outer side of the inclined groove 21. . For this reason, due to the action of averaging the pressure in the bearing space during rotation of the bearing, the lubricant constantly flows into the inclined groove 21 from the inner diameter side of the cage 14 during the rotation of the bearing, and the lubricant accumulated in the inclined groove 21. However, a sufficient amount of lubricant can be ensured by being supplied to the contact portion between the outer diameter side end surface 13a of the roller 13 and the outer diameter side end surface 15a of the pocket portion 15. As a result, similarly to the above-described embodiment, it is possible to satisfactorily prevent abnormal wear from occurring on the outer diameter side end surface 15a of the pocket portion 15 due to centrifugal force.

As in the first embodiment, by forming a sliding resistance reducing film such as a DLC film or a fluororesin coating film on the outer diameter side end surface 15a of the pocket portion 15 of the resin cage 14, by centrifugal force. Even when the roller 13 comes into contact with the pocket outer diameter side end surface 15a and rotates as it is, the occurrence of abnormal wear or abnormal heat generation can be avoided more reliably.
Also in the present embodiment, the sliding resistance reducing film only needs to include at least the vicinity of the outer diameter side end face 15a of the pocket portion 15 and may be applied to the entire resin cage 14.

Note that the present invention is not limited to the above-described embodiments, and appropriate modifications and improvements can be made without departing from the scope of the present invention.
For example, in the above embodiment, the case where the present invention is applied to the resin-made plate-like cages 14 and 22 is illustrated, but as shown in FIGS. 7 and 8, two annular metals having a substantially U-shaped cross section. The present invention is also applicable to the cage 34 in which the plates 31 and 32 are joined by caulking or the like to form an annular hollow body having a substantially rectangular cross section, and a plurality of pocket portions 33 are formed at substantially equal intervals in the circumferential direction.
That is, as shown in FIG. 7, it may be a thrust roller bearing 30 in which the curved groove 16 similar to that of the first embodiment is formed on the surface of the annular metal plate 31 constituting the cage 34. FIG. As shown, a thrust roller bearing 40 in which an inclined groove 21 similar to that of the second embodiment is formed on the surface of the annular metal plate 31 may be used.

In each of the above embodiments, the curved grooves 16 and the inclined grooves 21 are formed only on one surface of the cages 14 and 34, but the curved grooves 16 are formed on both surfaces of the cages 14 and 34. Alternatively, the inclined groove 21 may be formed.
However, if the curved grooves 16 and the inclined grooves 21 are provided only on one surface, it is preferable to provide them on the rotation side raceway ring 11 side as in this embodiment.

  The material, shape, dimensions, form, number, location, etc. of the pockets, rollers, cages, grooves, etc. exemplified in the above embodiments are arbitrary and not limited as long as the present invention can be achieved.

It is principal part sectional drawing for demonstrating the thrust roller bearing which is 1st Embodiment of this invention. FIG. 2 is a plan view of a cage incorporated in the thrust roller bearing of FIG. 1. (A) is the principal part enlarged view of the holder | retainer of FIG. 2 which shows the state by which the sliding resistance reduction film | membrane was formed in the outer diameter side end surface of a pocket part, (b) is III-III of (a). It is sectional drawing along a line. (A) is the principal part enlarged view of the holder | retainer of FIG. 2 which shows the state by which the sliding resistance reduction film | membrane was formed in the whole surface, (b) is the cross section along the IV-IV line of (a). FIG. It is principal part sectional drawing for demonstrating the thrust roller bearing which is 2nd Embodiment of this invention. It is a top view of the holder | retainer integrated in the thrust roller bearing of FIG. It is principal part sectional drawing which shows the modification of the thrust roller bearing of this invention. It is principal part sectional drawing which shows the other modification of the thrust roller bearing of this invention. It is principal part sectional drawing for demonstrating the conventional thrust roller bearing. FIG. 10 is a plan view of a cage incorporated in the thrust roller bearing of FIG. 9. It is principal part sectional drawing for demonstrating the other conventional thrust roller bearing.

Explanation of symbols

10, 20, 30, 40 Thrust roller bearing 13 Roller 15, 33 Pocket portion 14, 34 Cage 16 Curved groove 17 DLC film (sliding resistance reduction film)
21 Inclined groove

Claims (5)

  A thrust roller bearing having a roller and a cage having a pocket portion for holding the roller, wherein a groove communicating with the pocket portion is formed on a surface of the cage. Thrust roller bearing.   The thrust roller bearing according to claim 1, wherein the cage is made of resin.   The thrust roller bearing according to claim 2, wherein the cage includes a sliding resistance reducing film at least on an outer diameter side end face of the pocket portion.   The thrust roller bearing according to claim 3, wherein the sliding resistance reducing film is a diamond-like carbon film.   The thrust roller bearing according to claim 3, wherein the sliding resistance reduction film is a fluororesin coating film.

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