JP2006125604A - Thrust roller bearing - Google Patents

Abstract

A thrust roller bearing in which wear at a sliding portion between an end face of a rolling element and a cage is reduced.
SOLUTION: A plurality of rolling elements 2 formed in a columnar shape or a truncated cone shape and arranged with a central axis in a radial shape, and a plurality of rolling elements 2 formed in an annular shape around the circumference thereof. In a thrust roller bearing 1 including a cage formed with a plurality of pocket portions 4 to be accommodated, an inner wall surface 4a of the pocket portion 4 in contact with the end surface 2a disposed on the outer diameter side of the cage 3 of the rolling element, The lubricant holding layer that holds the lubricant is used.
[Selection] Figure 3

Description

  The present invention relates to a thrust roller bearing in which wear at a sliding portion between an end face of a rolling element and a cage is reduced.

The thrust roller bearing is used, for example, in an automatic transmission of a car or a rotating part of a compressor for a car air conditioner, and supports a load in an axial direction.
The thrust roller bearing includes a plurality of rollers formed in a substantially cylindrical shape as rolling elements, and the central axes thereof are arranged radially along the rotation axis of the support object. These rollers are arranged so as to be sandwiched between bearing discs each having a pair of raceways facing each other, and rotate around their central axes, whereby rotational motion between the respective raceways is performed.
Such a thrust roller bearing includes a thrust cylindrical roller bearing, a thrust needle roller bearing, a thrust tapered roller bearing, and the like depending on the shape of the roller.

The thrust roller bearing includes cages that hold the arrangement intervals along the circumferential direction of the plurality of rollers and the position in the radial direction. Usually, the cage is formed in an annular shape, and pocket portions are formed in which a plurality of rollers are respectively accommodated.
The cage is formed by joining a pair of metal plates with pocket portions formed by pressing, for example, or a ring plate shape made of a resin material, and an opening that penetrates both sides along the circumferential direction. Are arranged as pockets.

  If the cage is made of resin, it is lightweight, which is advantageous in reducing the weight of the entire bearing and increasing the allowable rotational speed. However, when a resin cage is used, there is a problem that during use, a lubricant such as fats and oils is difficult to be supplied to the sliding portion with the inner wall surface of the pocket portion.

  In contrast, conventionally, the surface of the cage between the pair of pocket portions is recessed to form a recess in which the lubricant accumulates, and from this recess, the sliding portion between the outer peripheral surface portion of the roller and the inner surface of the pocket portion. It is known that a lubricant is supplied to a resin (for example, Patent Document 1).

However, when the thrust roller bearing rotates, the roller rotates against the cage while being pressed against the end surface on the outer diameter side of the pocket portion by centrifugal force. Therefore, the end surface of the roller and the end surface of the pocket portion are rotated. In some cases, abnormal wear (also referred to as drilling wear) occurs. Such abnormal wear is particularly likely to occur when an oil film having a sufficient thickness is not formed as a result of not supplying a sufficient amount of lubricant to the sliding surface portion, resulting in a so-called boundary lubrication state.
Japanese Utility Model Publication No. 5-38419

  The subject of this invention is providing the thrust roller bearing which reduced the abrasion in the sliding part of the end surface of a rolling element, and a holder | retainer.

  The present invention solves the above problems by the following means. In addition, in order to make an understanding easy, it attaches | subjects and demonstrates the code | symbol corresponding to the Example of this invention, but this invention is not limited to this.

  According to the first aspect of the present invention, a plurality of rolling elements (2) formed in a columnar shape or a truncated cone shape and arranged in a radial manner with a central axis thereof are formed in an annular shape, and the plurality of rolling elements are arranged along the circumference thereof. In a thrust roller bearing (1) comprising a cage (3) formed with a plurality of pockets (4) in which the rolling elements (2) are respectively accommodated, the cage (3) of the rolling element (2) A thrust roller bearing (1) having a lubricant retaining layer for retaining a lubricant on the inner wall surface (4a) of the pocket portion (4) in contact with the end surface (2a) disposed on the outer diameter side of ).

According to a second aspect of the present invention, in the thrust roller bearing (1) according to the first aspect, the lubricant retaining layer includes a plurality of groove portions (5) formed on the inner wall surface (4a) of the pocket portion (4). A thrust roller bearing (1).
According to a third aspect of the present invention, in the thrust roller bearing (1) according to the second aspect of the present invention, the plurality of grooves (5) of the lubricant retaining layer are respectively substantially in the center axis of the retainer (3). The thrust roller bearing (1) is characterized in that it extends along a parallel direction, and at least one groove portion thereof is opened in a surface portion facing the raceway of the retainer (3).

According to the present invention, the following effects can be obtained.
(1) Since the wall surface of the pocket portion in contact with the end surface on the outer diameter side of the cage of the rolling element is provided with a lubricant retaining layer that holds the lubricant, the end surface of the rolling element and the wall surface of the pocket portion are Lubricant is supplied to the sliding portion between them, and abnormal wear due to insufficient lubrication can be prevented.
(2) Since the lubricant holding layer has a plurality of groove portions formed on the wall surface of the pocket portion, the lubricant flows along the groove portion and is distributed over the sliding surface portion to ensure a good lubricating state. be able to.
(3) The groove portion of the lubricant retaining layer extends along a direction substantially parallel to the central axis of the cage, and at least one end thereof opens to a surface portion facing the washer of the cage. Therefore, the lubricant can easily flow into the groove from this opening, and the amount of lubricant retained in the lubricant retaining layer can be ensured.

  The present invention extends to the inner wall surface of a pocket portion in contact with an end face of a roller disposed on the outer diameter side of a cage along a direction substantially parallel to the central axis of the cage, and the washer of the cage The above-described problems are solved by a thrust roller bearing in which a plurality of groove portions opened in a surface portion facing the surface are formed.

Hereinafter, the present invention will be described in more detail with reference to the drawings and the like.
FIG. 1 is a cross-sectional view showing a state in which an embodiment of a thrust roller bearing to which the present invention is applied is cut along a diameter. FIG. 2 is a view of the thrust roller bearing of the embodiment as seen from the direction of the rotation axis.

The thrust roller bearing 1 of the embodiment includes a needle roller 2 as a rolling element and a cage 3, and is used by being sandwiched between raceway surfaces formed on a pair of annular raceways (not shown). It is
The thrust roller bearing 1 receives an axial force acting between each washer, and supports each washer so as to be rotatable around a rotation center axis I thereof.
The roller 2 has a substantially constant outer diameter over its longitudinal direction and is formed in a cylindrical shape. End surfaces 2 a at both ends are flat surfaces that are substantially orthogonal to the central axis of the roller 2. Further, an R chamfer is applied to the boundary portion between the end surface 2 a and the outer peripheral surface 2 b of the roller 2.

As shown in FIG. 2, in the case of this embodiment, for example, eight rollers 2 are provided, and the circumference of the rollers is such that the central axis thereof is a radial shape centering on the rotation center axis I of the thrust roller bearing 1. Are arranged along. Further, as shown in FIG. 1, the central axis of the roller 2 is arranged in a direction substantially orthogonal to the rotational central axis I of the thrust roller bearing 1.
The rollers 2 are arranged so that the intervals along the circumferential direction are substantially equal, and the distances from the rotation center axis I are substantially the same.

  The cage 3 is made of, for example, a synthetic resin material such as nylon, and a circular opening substantially concentric with the outer peripheral edge of the disk is formed at the center of the disk disposed substantially concentrically with respect to the rotation center axis I of the thrust roller bearing 1. Formed in the shape of the formed ring plate, the pocket part 4 which accommodates each roller 2 is formed along the circumferential direction.

  The pocket portion 4 is a rectangular opening formed through the cage 3, and the shape and dimensions of the pocket portion 4 are such that the roller 2 rolls with a sufficiently low rolling resistance with respect to the outer shape of the roller 2 to be accommodated. Only a gap allowing movement is formed to be large in both the radial direction and the circumferential direction of the cage 3.

FIG. 3 is an enlarged view of one of the pocket portions 4 included in the cage 3. 4 is a cross-sectional view taken along the line IV-IV in FIG.
A plurality of fine groove portions 5 are formed on the inner wall surface 4a of the pocket portion 4 which is disposed on the outer diameter side of the cage 3 and contacts the end surface 2a of the roller 2 accommodated in the pocket portion 4.
The groove portion 5 is formed by denting the inner wall surface 4a of the pocket portion 4 and has a rectangular groove cross-sectional shape. The groove portions 5 are each substantially parallel to the rotation center axis I of the thrust roller bearing 1 and are arranged at substantially equal intervals.
Further, both end portions of the groove portion 5 are opened in the surface portions facing the raceway of each race of the cage 3.
The inner wall surface 4a of the pocket portion 4 is formed with the groove portion 5, thereby forming a lubricant receiving layer 6 for receiving and holding the lubricating oil as the lubricant.

  As described above, according to the present embodiment, the inner wall surface 4a of the pocket portion 4 in contact with the end surface 2a of the roller 2 disposed on the outer diameter side of the cage 3 is substantially the same as the rotation center axis I of the thrust roller bearing 1. Since a plurality of groove portions 5 extending along the parallel direction are formed and both end portions thereof are opened in the surface portions facing the respective races of the cage 3, they are supplied from the outside when the thrust roller bearing is used. Lubricant such as lubricating oil flows into the groove portion 5 along the inner diameter side of the pocket portion 4 and each surface portion facing the raceway surface of the cage 3, and after being held in the groove portion 5, the inner wall surface 4a 2 is supplied to the sliding surface portion with the end surface 2a, so that a sufficient amount of lubricant can be supplied to the sliding surface portion, and abnormal wear such as drilling wear can be prevented by maintaining a good lubricating state. be able to.

(Modification)
The present invention is not limited to the embodiments described above, and various modifications and changes are possible, and these are also within the equivalent scope of the present invention.
(1) Although the embodiment described above is a thrust needle roller bearing, the present invention is not limited to this, and can be applied to a thrust cylindrical roller bearing or a thrust tapered roller bearing.
(2) The material, shape and structure of the cage, and the shape and arrangement of the groove portions are not limited to those of the above-described embodiments.

It is sectional drawing of the Example of the thrust roller bearing to which this invention is applied. FIG. 2 is an axial view of the thrust roller bearing of FIG. 1. It is a principal part enlarged view of the cage | basket of the thrust roller bearing of FIG. FIG. 4 is a cross-sectional view taken along the line IV-IV in FIG. 3.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Thrust roller bearing 2 Roller 2a End surface 3 Cage 4 Pocket part 4a Inner wall surface 5 Groove part 6 Lubricant holding layer I Rotation center axis

Claims (3)

A plurality of rolling elements formed in a columnar shape or a truncated cone shape and arranged radially with a central axis thereof;
In a thrust roller bearing provided with a cage formed with an annular shape and formed with a plurality of pocket portions in which the plurality of rolling elements are accommodated, respectively.
A thrust roller bearing, comprising: a lubricant retaining layer that retains a lubricant on a wall surface of the pocket portion that is in contact with an end surface of the rolling element disposed on an outer diameter side of the cage. The thrust roller bearing according to claim 1,
The thrust roller bearing, wherein the lubricant retaining layer has a plurality of grooves formed in the wall surface of the pocket portion. In the thrust roller bearing according to claim 2,
Each of the plurality of groove portions of the lubricant retaining layer extends along a direction substantially parallel to the central axis of the retainer, and at least one end thereof faces the washer of the retainer. A thrust roller bearing having an opening in the surface portion.

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