JP2009103239A - Trust roller bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thrust roller bearing preventing contact between a cage and raceway surfaces. <P>SOLUTION: This thrust roller bearing 11 has first and second bearing rings 14 and 15, a plurality of rollers 12 arranged between the first and second bearing rings 14 and 15, and the cage 13 having a plurality of pockets for storing the rollers 12. The first and second bearing rings 14 and 15 have the raceway surfaces 14b and 15b respectively contacting with the rollers 12, and step height parts 14e, 14f, 15e and 15f contacting with the cage 13 in at least one among the radial directional inside and the radial directional outside of the raceway surfaces 14b and 15b. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a thrust roller bearing, and more particularly to a thrust roller bearing used for an automatic transmission, a transaxle or the like.

A thrust roller bearing used for an automatic transmission, a transaxle or the like of an automobile is described in, for example, Japanese Utility Model Laid-Open No. 7-12627 (Patent Document 1). The publication discloses a three-piece integral thrust roller bearing comprising a plurality of needle rollers, a cage that holds the needle rollers, and a pair of race rings that sandwich the plurality of needle rollers from the thickness direction of the cage. It is disclosed.
Japanese Utility Model Publication No. 7-12627

  In recent years, downsizing of automatic transmissions, compressors, and the like has progressed, and accordingly, there is a strong demand for reducing the thickness of thrust roller bearings used in these devices.

  When the thickness dimension of the thrust roller bearing is reduced, the possibility that the cage comes into contact with the raceway surface is increased. As a result, there is a problem in that torque loss increases or friction and wear between the roller and the raceway surface increase by scraping the oil film on the raceway surface.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a thrust roller bearing that prevents contact between a cage and a raceway surface (“the wall surface of a raceway that serves as a roller rolling region”; the same shall apply hereinafter).

  A thrust roller bearing according to the present invention includes a first and second race ring, a plurality of rollers disposed between the first and second race rings, and a cage having a plurality of pockets for accommodating the rollers. Is provided. Each of the first and second race rings has a raceway surface that contacts the roller, and a step portion that contacts the cage on at least one of the radially inner side and the radially outer side of the raceway surface.

  Thereby, it can prevent that a holder | retainer and a raceway surface contact during bearing rotation. As a result, the oil film formed on the raceway surface is not scraped off, so that the oil film state can be kept good. In the present specification, the “stepped portion” refers only to a step on the side approaching the raceway facing with respect to the raceway surface.

  Preferably, the raceway surface functions as an oil reservoir that holds the lubricant. Thereby, the lubricating performance is further improved.

  Preferably, the height difference h in the thickness direction of the stepped portion satisfies 0 mm <h <0.3 mm. The stepped portion may be formed with a slight height difference on the wall surface on one side in the thickness direction of the raceway so that the cage and the raceway surface do not contact each other.

  Preferably, at least one of the stepped portion and the wall surface of the cage that contacts the stepped portion is formed with a phosphate coating and a solid lubricant coating on the surface of the phosphate coating. Thereby, the contact resistance between the cage and the raceway can be relaxed, and the torque loss of the thrust roller bearing can be reduced.

  Preferably, the step portion is formed by pressing the race. Thereby, manufacturing cost can be reduced.

  If the amount of axial movement of the roller in the pocket is Δt and the distance between the cage and the step portion is H, Δt> H is satisfied. Thereby, it can prevent that a holder | retainer obstructs the smooth rotation of a roller.

  According to this invention, the contact between the cage and the raceway surface can be prevented by providing the raceway with a step. As a result, oil film breakage on the raceway surface can be prevented and a good lubrication state can be maintained, so that a long-life thrust roller bearing can be obtained. Further, by providing a step in the raceway, the contact area between the cage and the raceway is reduced. As a result, the rotational torque can be reduced as compared with the conventional thrust roller bearing.

  With reference to FIGS. 1-4, the thrust roller bearing 11 which concerns on one Embodiment of this invention is demonstrated. 1 is a view showing a thrust roller bearing 11, FIG. 2 is an enlarged view of a portion P in FIG. 1, FIG. 3 is a sectional view taken along line III-III in FIG. 2, and FIG. FIG.

  First, the thrust roller bearing 11 includes a plurality of rollers 12, a retainer 13 that retains the plurality of rollers 12, and first and second race rings 14 that sandwich the plurality of rollers 12 from the thickness direction of the retainer 13. 15.

  The first track ring 14 is a disk-shaped member having a through hole 14a in the center. And the 1st track surface 14b which contacts the roller 12 on the wall surface of the thickness direction one side, the cylindrical outer periphery collar part 14c which protrudes from the outer edge part to the thickness direction one side (upper side of FIG. 1), and an outer periphery collar part The first staking 14d protrudes radially inward from the tip of 14c, and step portions 14e and 14f are included on the wall surface on one side in the thickness direction.

  The first raceway surface 14 b is a rolling region of the rollers 12. The first raceway surface 14b also functions as an oil reservoir that holds the lubricant. Thereby, lubrication performance improves. When the thrust roller bearing 11 is assembled, the outer peripheral flange portion 14 c is positioned further outside the outer diameter surface of the cage 13. The first staking 14 d engages with the outer edge of the cage 13 to prevent the cage 13 from being separated from the first race ring 14.

  The step portion 14e is provided in a region radially inward of the first raceway surface 14b, and the step portion 14f is provided in a region radially outward of the first raceway surface 14b. The first raceway surface 14 b is provided at a relatively retracted position on the wall surface on one side in the thickness direction of the first raceway ring 14. On the other hand, the stepped portions 14e and 14f are provided at relatively advanced positions on the wall surface on one side in the thickness direction of the first track ring 14.

  The step portions 14e and 14f function as a cage guide surface that comes into contact with the wall surface on one side in the thickness direction of the cage 13 (upper side in FIG. 1). Thereby, it can prevent that the holder | retainer 13 and the 1st track surface 14b contact during a bearing rotation. As a result, the oil film formed on the first raceway surface 14b is not scraped off, so that the oil film state can be kept good. Further, since the contact area between the cage 13 and the first raceway ring 14 is reduced, the rotational torque can be reduced as compared with a conventional thrust roller bearing.

  Referring to FIG. 2, various dimensions are set so that the height difference h in the thickness direction of the stepped portions 14e and 14f satisfies 0 mm <h <0.3 mm. The stepped portions 14e and 14f may form a slight height difference on the wall surface on one side in the thickness direction of the first race ring 14 so that the cage 13 and the first raceway surface 14b do not contact each other.

  The first race ring 14 having the above-described configuration is formed by press working using, for example, an SCM material, an SCr material, an SPC material, an SK material, or the like as a starting material. Specifically, first, a die (not shown) is brought into contact with a portion that becomes the first track surface 14b of the wall surface on one side in the thickness direction (the upper side in FIG. 1) of the disk-shaped member. And the area | region of radial direction outer side and radial direction inner side from the part corresponding to the 1st track surface 14b are extruded with a punch (illustration omitted) toward the thickness direction one side from the thickness direction other side (lower side of FIG. 1). Thereby, the step portions 14e and 14f are formed.

  Next, the outer peripheral flange 14c and the first staking 14d are formed. Next, heat treatment is performed to impart predetermined mechanical properties to the first race ring 14. For example, the hardness Hv is set to about 653 to 800. Next, the surface of the first raceway surface 14b and the like is smoothed by barrel polishing.

Further, at least one of the stepped portions 14e and 14f and the wall surface of the cage 13 in contact with the stepped portions 14e and 14f has a phosphate coating (not shown) as a first layer and a second surface on the surface of the phosphate coating. A solid lubricant film (not shown) is formed as a layer. Thereby, the contact resistance between the cage 13 and the first race 14 can be relaxed, and the torque loss of the thrust roller bearing 11 can be reduced. As the solid lubricant, polytetrafluoroethylene (PTFE), molybdenum disulfide (MoS ₂ ), tungsten sulfide (WS ₂ ), silver (Ag), tin (Sn), or the like can be used.

  The second race 15 is a disk-shaped member having a through hole 15a in the center. A second raceway surface 15b that contacts the roller 12 on the wall surface on one side in the thickness direction, a cylindrical inner peripheral flange 15c that protrudes from the inner edge to one side in the thickness direction (the lower side in FIG. 1), The second staking 15d protrudes radially outward from the distal end of the peripheral flange portion 15c, and the step portions 15e and 15f are included on the wall surface on one side in the thickness direction.

  When the thrust roller bearing 11 is assembled, the inner peripheral flange portion 15 c is positioned further inside the inner diameter surface of the cage 13. The second staking 15 d is engaged with the inner edge of the cage 13 to prevent the cage 13 from being separated from the second race ring 15. Since other components, starting materials, manufacturing methods, and the like are the same as those of the first race ring 14, description thereof is omitted.

Here, the eccentric amount of the thrust roller bearing 11 is e (not shown), the gap between the outer peripheral surface of the retainer 13 and the outer peripheral flange 14c is δ ₁ , and the inner peripheral surface of the retainer 13 and the inner peripheral flange 15c. Various dimensions are set so that e <δ ₁ + δ ₂ , where δ ₂ is the gap between the _two .

  Thereby, even when the thrust roller bearing 11 rotates eccentrically, a gap is always formed between the retainer 13 and the outer peripheral flange 14c and between the retainer 13 and the inner peripheral flange 15c. As a result, it is possible to prevent the cage 13 from being sandwiched between the outer peripheral flange 14c and the inner peripheral flange 15c and being damaged.

Further, a gap between one end face of the roller 12 (left end face in FIG. 2) and the stepped portion 14f of the first race 14 is σ ₁ , and the other end face of the roller 12 (right end face in FIG. 2). When the gap between the stepped portion 14e of the first track ring 14 is σ ₂ , various dimensions are set so that e <δ ₁ + δ ₂ <σ ₁ + σ ₂ .

  With the above configuration, even when the thrust roller bearing 11 rotates eccentrically, the roller 12 does not interfere with the step portions 14e, 14f, 15e, and 15f. As a result, it is possible to obtain a thrust roller bearing 11 in which the roller 12 can smoothly rotate even when used in an eccentric rotation environment. The above relationship is similarly established between the roller 12 and the second race 15.

In the embodiment shown in FIG. 2, the thrust roller bearing 11 is not eccentrically rotated, that is, the rotation axes of the cage 13 and the first and second race rings 14 and 15 are the same, and the roller In a state where 12 is located at the center of the pocket 13a, δ ₁ = δ ₂ <σ ₁ = σ ₂ holds.

  The cage 13 is a disk-shaped member and is a so-called M-type cage having a substantially M-shaped cross section. A plurality of pockets 13 a for accommodating the rollers 12 are formed on the wall surface of the cage 13. Further, referring to FIG. 3, the pocket 13a is unevenly distributed on one side in the thickness direction and the first roller stopper 13b is prevented from coming off to one side in the thickness direction of the roller 12, and unevenly distributed on the other side in the thickness direction. And the 2nd roller stop part 13c which prevents the roller 12 from detaching to the other side in the thickness direction is provided.

  3 and 4, if the axial movement amount of the roller 12 in the pocket 13a is Δt and the distance between the retainer 13 and the step portions 14e, 14f, 15e, 15f is H, Δt> H Meet.

  The “distance H between the cage 13 and the stepped portion” means the thickness dimension of the cage 13 from the distance between the stepped portions 14e, 14f of the first raceway ring 14 and the stepped portions 15e, 15f of the second raceway ring 15. Matches the length minus. For example, the distance between the retainer 13 and the stepped portions 15e and 15f of the second track ring 15 when the retainer 13 and the stepped portions 14e and 14f of the first tracked ring 14 are in contact with each other is H.

On the other hand, “the amount of movement of the roller 12 in the axial direction” refers to a length in which the roller 12 can move in the pocket 13a in the axial direction without the races 14 and 15. Specifically, O ₁ is the roller center when the roller 12 is in contact with the first roller stopper 13b (the roller 12 ′ indicated by a one-dot chain line in FIG. 4), and the roller 12 is the second roller stopper. the center roller at the contact state (12 '' time indicated by the two-dot chain line in FIG. 4) When O ₂ to 13c, the axial movement amount Δt distance 12 of the roller between the O ₁ and O ₂ Match.

  With the above configuration, the axial movement of the cage 13 is restricted by the step portions 14e, 14f, 15e, and 15f before the rollers 12 come into contact with the stopper portions 13b and 13c. Thereby, the roller 12 can rotate smoothly.

  In addition, in said embodiment, although the example which employ | adopted what was called a M-type holder | retainer 13 was shown, the holder | retainer of arbitrary shapes can be employ | adopted not only to this. For example, as shown in FIG. 5, a so-called box-type cage 23 formed by combining two steel plates may be used, or as shown in FIG. 6, compared with the steel plates constituting the cages 13 and 23. The cage 33 may be relatively thick. Furthermore, it is not limited to a metal cage, and may be a resin cage. 5 and 6, common components are denoted by the same reference numerals as in FIGS. 1 to 4, and description thereof is omitted.

  In the above embodiment, the example in which the step portions 14e, 14f, 15e, and 15f are provided at the two locations of the first and second race rings 14 and 15 has been described. If provided in one place, the effect of the present invention can be obtained.

  For example, referring to FIG. 7, the first track ring 44 is provided with a stepped portion 44e only in a region radially inward from the first track surface 14b. Similarly, the second race 45 is provided with a step 45e only in a region radially inward from the second race surface 15b. Furthermore, as a modification of FIG. 7, a stepped portion may be provided only on the radially outer side from the raceway. In FIG. 7, common constituent elements are denoted by the same reference numerals as in FIGS. 1 to 6, and descriptions thereof are omitted.

  In each of the above-described embodiments, an example in which the stepped portion is formed by pressing the raceway is shown. However, the present invention is not limited to this and can be formed by any method. For example, the position of the raceway surface may be turned to reduce the plate thickness. According to the turning process, the surface on the other side in the thickness direction of the race (refer to the “opposite surface”) is a flat surface.

  Further, the present invention can be applied to all types of thrust roller bearings having needle rollers, rod rollers, or cylindrical rollers as rollers. However, a thrust needle roller bearing is desirable from the viewpoint of reducing the thickness dimension.

  Furthermore, the thrust roller bearing according to the present invention can be used in any device other than an automatic transmission and a transaxle.

  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 present invention is advantageously used for a thrust roller bearing.

It is a figure which shows the thrust roller bearing which concerns on one Embodiment of this invention. It is an enlarged view of the P section of FIG. It is sectional drawing in III-III of FIG. It is a figure which shows the amount of axial movement of a roller. It is a figure which shows the thrust roller bearing which concerns on other embodiment of this invention, Comprising: It is a figure corresponding to FIG. It is a figure which shows the thrust roller bearing which concerns on other embodiment of this invention, Comprising: It is a figure corresponding to FIG. It is a figure which shows the thrust roller bearing which concerns on other embodiment of this invention, Comprising: It is a figure corresponding to FIG.

Explanation of symbols

  11 Thrust roller bearing, 12 rollers, 13, 23, 33 cage, 13a pocket, 13b, 13c roller stopper, 14, 15, 44, 45 race ring, 14a, 15a through hole, 14b, 15b raceway surface, 14c, 15c collar part, 14d, 15d staking, 14e, 14f, 15e, 15f, 44e, 45e A step part.

Claims (6)

First and second races;
A plurality of rollers disposed between the first and second race rings;
A cage having a plurality of pockets for accommodating the rollers,
The first and second race rings each have a raceway surface that contacts the roller, and a step portion that contacts the cage on at least one of the radially inner side and the radially outer side of the raceway surface, Thrust roller bearing.   The thrust roller bearing according to claim 1, wherein the raceway surface functions as an oil reservoir for holding a lubricant.   The thrust roller bearing according to claim 1, wherein the height difference h in the thickness direction of the stepped portion satisfies 0 mm <h <0.3 mm.   The phosphate coating and the solid lubricant coating on the surface of the phosphate coating are formed on at least one of the stepped portion and the wall surface of the cage that contacts the stepped portion. 4. A thrust roller bearing according to any one of 3 above.   The thrust roller bearing according to any one of claims 1 to 4, wherein the step portion is formed by pressing the raceway. When the amount of axial movement of the roller in the pocket is Δt and the distance between the cage and the step portion is H,
The thrust roller bearing according to claim 1, wherein Δt> H is satisfied.

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