Thrust bearing

Abstract

The problem to be solved by the present disclosure is to provide a thrust bearing capable of suppressing bending of a cover during crimping so as to accurately set a gap between the cover and a raceway disc. A thrust bearing (1) is provided with a cover (40) that is disposed so as to cover the outer peripheral surfaces of a first raceway disc (10) and a second raceway disc and that holds the first raceway disc (10) and the second raceway disc in the axial direction, the cover (40) having: a cylindrical section (41) that faces the outer peripheral surfaces of the first raceway disc (10) and the second raceway disc; and a bent section (42) which is bent over the entire circumference with respect to the cylindrical section (41) at at least one of the axial end sections of the cylindrical section (41), and wherein a chamfered section (12) is formed at the corner of the outer peripheral surface of at least one of the first raceway disc (10) and the second raceway disc, and the chamfered section (12) faces the bent section (42) of the cover (40). In order to solve the problem, a circumferential groove (44) is formed in the boundary portion between the bent portion (42) and the cylindrical portion (41) over the entire circumference of the inner circumferential surface.

Description

Technical Field

[0001] The present invention relates to a thrust bearing, and more particularly to an improvement of a cover for combining a first raceway disk and a second raceway disk. Background Art

[0002] A thrust bearing is a bearing that has rolling elements disposed between a first raceway and a second raceway and bears a thrust load. In order to prevent the first raceway from separating from the second raceway, a cover is sometimes disposed to cover the outer circumference of the two raceways (see, for example, Patent Documents 1 and 2).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 8-004759

[0006] Patent Document 2: Japanese Patent Application Publication No. 2020-143708 Summary of the invention

[0007] Problems to be solved by the invention

[0008] The end of the cylindrical portion of the cover is bent to provide a portion opposite to the chamfered portion provided at the corner of the raceway disk, so that the cover is shaped to prevent the raceways disks from being separated from each other. However, when the end of the cylindrical portion is crimped, the cover may bend, in which case the gap between the cover and the raceway disk may be uneven.

[0009] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a thrust bearing capable of accurately setting the gap between the cover and the raceway plate by suppressing the bending of the cover during curling.

[0010] Solutions for solving problems

[0011] The present invention is a thrust bearing comprising: a first raceway having a raceway groove; a second raceway having a raceway groove; a rolling element arranged between the raceway groove of the first raceway and the raceway groove of the second raceway; and a retaining unit arranged in a manner covering the outer circumference or inner circumference of the first raceway and the second raceway to retain the first raceway and the second raceway in an axial direction, the retaining unit comprising: a cylindrical portion opposed to the outer circumference or inner circumference of the first raceway and the second raceway; and a bent portion, at least one of the axial ends of the cylindrical portion being bent relative to the cylindrical portion throughout the entire circumference, a chamfered portion being formed at a corner of the outer circumference or inner circumference of at least one of the first raceway and the second raceway, the chamfered portion being opposed to the bent portion of the retaining unit, wherein a circumferential groove extending throughout the entire circumference of the inner circumference or the outer circumference is formed at a boundary portion between the bent portion and the cylindrical portion.

[0012] In addition, the present invention is a method for manufacturing a thrust bearing, the thrust bearing comprising: a first raceway disk having a raceway groove; a second raceway disk having a raceway groove; a rolling element arranged between the raceway groove of the first raceway disk and the raceway groove of the second raceway disk; and a retaining unit arranged in a manner covering the outer circumferential surface or the inner circumferential surface of the first raceway disk and the second raceway disk, and retaining the first raceway disk and the second raceway disk in the axial direction, the retaining unit comprising: a cylindrical portion facing the outer circumferential surface or the inner circumferential surface of the first raceway disk and the second raceway disk; and A bending portion, wherein at least one end side of the axial end portions of the cylindrical portion is bent relative to the cylindrical portion throughout the entire circumference, and a chamfered portion is formed at a corner portion of the outer circumferential surface or the inner circumferential surface of at least one of the first raceway disk and the second raceway disk, and the chamfered portion is opposite to the bending portion of the retaining unit. In the manufacturing method of the thrust bearing, the cylindrical portion and the bending portion are formed into cylindrical shapes with the same cross-section, and a circumferential groove is formed at the end portion of the cylindrical portion throughout the entire circumference of the inner circumferential surface or the outer circumferential surface, and the bending portion is bent at the circumferential groove to perform curling forming on the bending portion.

[0013] Effects of the Invention

[0014] According to the present invention, it is possible to provide a thrust bearing capable of accurately setting a gap between a holding unit and a raceway plate by suppressing bending of the holding unit during curling. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a cross-sectional view showing a thrust bearing according to a first embodiment of the present invention.

[0016] Figure 2 It is an enlarged cross-sectional view showing a main part of the thrust bearing according to the embodiment.

[0017] Figure 3 It is a cross-sectional view showing a state before curling of the cover in the first embodiment.

[0018] Figure 4 In the figure, (A) is a cross-sectional view showing a state of a cover before curling in a conventional example, and (B) is a cross-sectional view showing a state of the cover after curling.

[0019] Figure 5 In the drawings, (A) is a cross-sectional view showing a state before curling of a cover in a modification example of the first embodiment, and (B) is a cross-sectional view showing a state after curling of the cover.

[0020] Figure 6 , (A) is a cross-sectional view showing a state before curling of a cover in a thrust bearing according to a second embodiment of the present invention, and (B) is a cross-sectional view showing the cover after curling.

[0021] Figure 7 In the figure, (A) is a cross-sectional view showing a state before curling of a cover in a modification example of the second embodiment, and (B) is a cross-sectional view showing the cover after curling. DETAILED DESCRIPTION

[0022] 1. First Implementation

[0023] Reference Figure 1 to Figure 4 , a thrust bearing according to an embodiment of the present invention is described. It should be noted that in the following description, "axial direction" means the direction of the central axis of the thrust bearing, and "radial direction" means the direction orthogonal to the axial direction. In addition, "circumferential direction" means the direction of rotation around the central axis. Furthermore, terms indicating directions such as "up" and "down" indicate Figure 1 The up and down directions in .

[0024] Figure 1 1 is a cross-sectional view showing a thrust bearing 1 according to an embodiment. The thrust bearing 1 includes a first raceway 10 and a second raceway 20 disposed opposite to each other. The first raceway 10 and the second raceway 20 are annular, and raceway grooves 11 and 21 having arc-shaped cross sections are formed on their opposing surfaces over the entire circumference.

[0025] A plurality of rolling elements 30 are arranged at equal intervals in the circumferential direction on the raceway ring having a circular cross section formed by the raceway grooves 11 and 21. The rolling element 30 is spherical, and the distance between the rolling element 30 and the adjacent rolling element 30 is kept constant by a cage (not shown).

[0026] A chamfered portion 12 is formed over the entire circumference of the axially upper corner of the outer circumference of the first raceway 10. In addition, a chamfered portion 22 is formed over the entire circumference of the axially upper corner of the outer circumference of the second raceway 20. The first raceway 10 and the second raceway 20 are equipped with a cover (holding means) 40 that covers the outer circumferences thereof.

[0027] The cover 40 is substantially cylindrical, and is composed of a cylindrical portion 41 facing the outer circumferential surface of the first raceway disc 10 and the second raceway disc 20, and bent portions 42 and 43 bent inwardly at the axial upper and lower ends of the cylindrical portion 41. The axially upper bent portion 42 faces the chamfered portion 12 of the first raceway disc 10, and the axially lower bent portion 43 faces the chamfered portion 22 of the second raceway disc 20. A circumferential groove 44 is formed at the boundary between the bent portion 42 and the cylindrical portion 41.

[0028] 2. Assembly method of thrust bearing

[0029] First, the bent portion 43 is formed on the axial lower side of the cylindrical component of the cover 40. In this case, a circular plate-shaped blank is punched out from a flat plate, and the blank is drawn into a cup shape having a tapered portion at the corner to become the bent portion 43. Next, the inner side of the tapered portion is punched out to form the cover 40 component having the bent portion 43.

[0030] A plurality of rolling elements 30 held by a cage (not shown) are placed on the rolling grooves 21 of the second raceway plate 20, and the first raceway plate 10 is placed from above the plurality of rolling elements 30. The assembly is inserted into the cover 40 having the bent portion 43 formed thereon. Figure 3 As shown, a peripheral groove 44 is formed on the inner periphery of the axially upper end portion of the cover 40 over the entire periphery.

[0031] The circumferential groove 44 is V-shaped in cross section, and its depth is less than 1 / 2 of the thickness of the cylindrical portion 41 of the cover 40, preferably less than 1 / 3 of the thickness of the cylindrical portion 41. Then, the outer peripheral surface of the upper portion of the circumferential groove 44 is rolled and crimped to form the bent portion 42. As a result, the first raceway 10 and the second raceway 20 are in a state where they cannot be separated in the axial direction due to the bent portions 42 and 43 of the cover 40.

[0032] 3. Effect

[0033] In the thrust bearing 1 of the above structure, a circumferential groove 44 is formed at the boundary between the bent portion 42 of the cover 40 and the cylindrical portion 41, and the circumferential groove 44 has a thin bottom wall thickness. Therefore, when the bent portion 42 is rolled and curled, stress is concentrated, and the circumferential groove 44 is crushed, so that it is deformed in a manner of bending at the circumferential groove 44. In addition, the rolling and curling is completed at the stage where the two inner side surfaces of the circumferential groove 44 with a V-shaped cross section are in close contact with each other. Therefore, if Figure 2 As shown, the cross-sectional shape of the bent portion 42 is a straight line or a shape approximately in a straight line.

[0034] In contrast, Figure 4As shown in (A), in the existing thrust bearing without the circumferential groove 44, when the bend portion 42 is formed by the curling, the stress will be uniformly applied to the portion that becomes the bend portion 42, as shown in FIG. Figure 4 As shown in (B), the cross-sectional shape of the bent portion 42 is a curved shape, and the size of the gap between the bent portion 42 and the first raceway plate 10 may be uneven.

[0035] Thus, in the thrust bearing 1 of the first embodiment, the bending of the bent portion 42 during curling can be suppressed and the bent portion 42 can be made linear or substantially linear, so that the gap between the bent portion 42 and the first raceway 10 can be accurately set.

[0036] In particular, in the above-mentioned first embodiment, the circumferential groove 44 before curling is formed into a V-shaped cross-section so that the two inner side surfaces of the circumferential groove 44 are in close contact with each other after curling. Therefore, the angle between the bending portion 42 and the cylindrical portion 41 can be set by setting the opening angle of the circumferential groove 44, and the gap between the front end edge of the bending portion 42 and the chamfered portion 12 of the first raceway disc 10 can be accurately set.

[0037] Furthermore, in the first embodiment, the depth of the circumferential groove 44 is set to be less than 1 / 2 of the thickness of the cylindrical portion 41 of the cover 40, preferably less than 1 / 3 of the thickness of the cylindrical portion 41, thereby ensuring the strength of the cover 40 to firmly combine the first raceway disc 10 and the second raceway disc 20.

[0038] In the first embodiment, the two inner side surfaces of the peripheral groove 44 are closely attached to each other after the curling, but it is also possible to Figure 5 As shown, the opening angle of the circumferential groove 54 is set large so that the circumferential groove 54 has a V-shaped cross section after curling. In this case, the two inner side surfaces of the circumferential groove 44 will also contact near their intersection (near the bottom of the circumferential groove 44), and the load required for further bending will increase, so that the angle between the bent portion 42 and the cylindrical portion 41 can be controlled, and the gap between the front end edge of the bent portion 42 and the chamfered portion 12 of the first raceway disc 10 can be accurately set.

[0039] 4. Second Implementation

[0040] Reference Figure 6 , a second embodiment of the present invention is described. In the second embodiment, the cross-sectional shape of the circumferential groove 64 before curling is made semi-elliptical. In such a circumferential groove 64, when the bending portion 42 is formed by curling, the axial edges of the two inner side surfaces of the circumferential groove 64 will be in close contact with each other after curling. Therefore, in this second embodiment, the angle between the bending portion 42 and the cylindrical portion 41 can also be set by setting the interval between the axial edges of the inner side surface of the circumferential groove 64, and the gap between the front end edge of the bending portion 42 and the chamfered portion 12 of the first raceway disc 10 can be accurately set.

[0041] Figure 7 1 is a diagram showing a modified example of the second embodiment. In this modified example, the cross-sectional shape of the peripheral groove 74 before curling is made semicircular. Even after the bending portion 42 is formed by curling, the peripheral groove 74 is open. It should be noted that the cross-sectional shape of the peripheral groove 74 can also be semi-elliptical or U-shaped.

[0042] 5. Change Examples

[0043] The present invention is not limited to the above-described embodiment, and various modifications are possible as follows.

[0044] i) In the above embodiment, the cover 40 is provided on the outer circumference of the first raceway disc 10 and the second raceway disc 20, but it may be provided on the inner circumference. In this case, chamfered portions are formed at the corners of the axial ends of the inner circumference of the first raceway disc 10 and the second raceway disc 20, and bent portions are formed at both ends of the cover to face the chamfered portions.

[0045] ii) The rolling element 30 is not limited to a spherical rolling element, and a cylindrical or truncated cone rolling element may be used.

[0046] iii) In the above embodiment, the first raceway disc 10 and the second raceway disc 20 are formed with arc-shaped raceway grooves 11 and 21 throughout the entire circumference, but a spherical recessed portion supporting the rolling element 30 may be formed in the second raceway disc 20, and the surface of the first raceway disc 10 facing the recessed portion may be formed flat. The same is true when the rolling element 30 is cylindrical or truncated cone-shaped.

[0047] Industrial Applicability

[0048] The present invention can be applied to all thrust bearings, such as kingpin thrust bearings used in suspensions of automobiles, etc., and bolts in which one raceway plate is fixed to the head to reduce the torque during tightening.

[0049] Description of Reference Numerals

[0050] 1: thrust bearing; 10: first raceway disk; 20: second raceway disk; 11, 21: raceway groove; 30: rolling element; 12, 22: chamfered portion; 40: cover; 41: cylindrical portion; 42, 43: bent portion; 44, 54, 64, 74: circumferential groove.

Claims

1. A thrust bearing, comprising: a first raceway having a raceway groove; a second raceway having a raceway groove; a rolling element disposed between the raceway groove of the first raceway and the raceway groove of the second raceway; and a retaining unit disposed in a manner covering the outer circumferential surface or the inner circumferential surface of the first raceway and the second raceway to retain the first raceway and the second raceway in the axial direction, The holding unit comprises: a cylindrical portion facing the outer circumferential surface or the inner circumferential surface of the first raceway disk and the second raceway disk; and a bent portion, at least one of the axial ends of the cylindrical portion being bent relative to the cylindrical portion over the entire circumference, A chamfered portion is formed at a corner of an outer circumferential surface or an inner circumferential surface of at least one of the first raceway plate and the second raceway plate, and the chamfered portion faces the bent portion of the holding unit. in, A circumferential groove is formed at a boundary portion between the bent portion and the cylindrical portion over the entire circumference of the inner circumferential surface or the outer circumferential surface.

2. The thrust bearing according to claim 1, wherein: The depth of the circumferential groove is less than or equal to 1 / 2 of the thickness of the cylindrical portion of the holding unit.

3. The thrust bearing according to claim 2, wherein: The depth of the circumferential groove is less than or equal to 1 / 3 of the thickness of the cylindrical portion of the holding unit.

4. The thrust bearing according to any one of claims 1 to 3, wherein: The inner side surface of the circumferential groove on one axial side is at least partially in contact with the inner side surface on the other axial side.

5. The thrust bearing according to any one of claims 1 to 4, wherein: The inner side surface of the circumferential groove on one axial side and the inner side surface on the other axial side are in contact with each other as a whole.

6. The thrust bearing according to any one of claims 1 to 3, wherein: The circumferential groove has a substantially V-shaped cross section.

7. The thrust bearing according to any one of claims 1 to 3, wherein: The circumferential groove has a substantially oblong cross-section, and an end edge of an inner side surface on one axial side of the circumferential groove and an end edge of an inner side surface on the other axial side of the circumferential groove are in contact with each other.

8. The thrust bearing according to any one of claims 1 to 3, wherein: The circumferential groove has a substantially U-shaped cross section.

9. A method for manufacturing a thrust bearing, the thrust bearing comprising: a first raceway having a raceway groove; a second raceway having a raceway groove; a rolling element disposed between the raceway groove of the first raceway and the raceway groove of the second raceway; and a retaining unit disposed in a manner covering the outer circumference or the inner circumference of the first raceway and the second raceway to retain the first raceway and the second raceway in the axial direction, The holding unit comprises: a cylindrical portion facing the outer circumferential surface or the inner circumferential surface of the first raceway disk and the second raceway disk; and a bent portion bent over the entire circumference of at least one end side of the axial end portions of the cylindrical portion relative to the cylindrical portion. A chamfered portion is formed at a corner of an outer circumferential surface or an inner circumferential surface of at least one of the first raceway plate and the second raceway plate, and the chamfered portion faces the bent portion of the holding unit. In the method for manufacturing the thrust bearing, The cylindrical portion and the bent portion are formed into cylindrical shapes with the same cross-section, a circumferential groove is formed over the entire circumference of the inner circumference or the outer circumference at the end point of the cylindrical portion, and the bent portion is bent at the circumferential groove to perform curling molding.

10. The method for manufacturing a thrust bearing according to claim 9, wherein: In the curling process, at least a portion of an inner side surface on one axial side and an inner side surface on the other axial side of the circumferential groove are brought into contact with each other.

11. The method for manufacturing a thrust bearing according to claim 9, wherein: The inner side surface on one axial side of the circumferential groove and the inner side surface on the other axial side are entirely in contact with each other.

12. The method for manufacturing a thrust bearing according to claim 9, wherein: The inner side surface on one axial side of the circumferential groove is separated from the inner side surface on the other axial side, so that the cross section of the circumferential groove after curling is substantially V-shaped.

13. The method for manufacturing a thrust bearing according to claim 9, wherein: The circumferential groove has a substantially semicircular or U-shaped cross section, and an end edge of an inner side surface on one axial side of the circumferential groove and an end edge of an inner side surface on the other axial side are in contact with each other.

14. The method for manufacturing a thrust bearing according to claim 9, wherein: The circumferential groove has a substantially semicircular or U-shaped cross section, and an end edge of an inner side surface on one axial side of the circumferential groove is separated from an end edge of an inner side surface on the other axial side of the circumferential groove.

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