Thrust bearings and their manufacturing methods

Abstract

This invention provides a thrust bearing capable of suppressing cap bending during riveting and accurately setting the gap between the cap and the track disk, and a method for manufacturing the same. A thrust bearing 1 includes a cap 40, which is configured to cover the outer peripheral surfaces of a first track disk 10 and a second track disk and axially holds the first track disk 10 and the second track disk. The cap 40 has: a cylindrical portion 41 facing the outer peripheral surfaces of the first track disk 10 and the second track disk; and a buckling portion 42 located at at least one end of the axial end of the cylindrical portion 41, buckling circumferentially relative to the cylindrical portion 41. A chamfered portion 12 is formed at a corner of the outer peripheral surface of at least one of the first track disk 10 and the second track disk, the chamfered portion 12 facing the buckling portion 42 of the cap 40. A circumferential groove 44 extending throughout the inner peripheral surface is formed at the boundary between the buckling portion 42 and the cylindrical portion 41.

Description

Technical Field

[0001] This invention relates to a thrust bearing, and more particularly to an improvement of a cover for combining a first track disk and a second track disk. Prior Technology

[0002] A thrust bearing is a bearing in which rolling elements are arranged between a first track disk and a second track disk to bear thrust loads. For purposes such as preventing separation of the first track disk and the second track disk, a cover is sometimes provided to cover the outer periphery of the two track disks (for example, Japanese Patent Application Publication No. Hei 8-004759 and Japanese Patent Application Publication No. 2020-143708). Summary of the Invention

[0003] The cover is shaped such that the track discs are prevented from separating by bending the end of its cylindrical portion and providing a portion facing the chamfered portion provided at the corner of the track disc. However, when riveting the end of the cylindrical portion, the cover may bend, in which case the gap between the cover and the track disc will deviate.

[0004] The present invention was made in view of the above circumstances, and its object is to provide a thrust bearing that can suppress the bending of the cover during riveting and accurately set the gap between the cover and the track plate.

[0005] The present invention is a thrust bearing comprising: a first track disk having a track groove; a second track disk having a track groove; a rolling element disposed between the track groove of the first track disk and the track groove of the second track disk; and a retaining unit disposed to cover the outer or inner circumferential surfaces of the first and second track disks and to retain the first and second track disks axially. The retaining unit comprises: a cylindrical portion facing the outer or inner circumferential surfaces of the first and second track disks; and a buckling portion located at at least one end of the axial end of the cylindrical portion, buckling circumferentially relative to the cylindrical portion, and a chamfered portion formed at a corner of the outer or inner circumferential surface of at least one of the first and second track disks. In the thrust bearing where the chamfered portion faces the buckling portion of the retaining unit, a circumferential groove extending throughout the entire circumference of the inner or outer circumferential surface is formed at the boundary between the buckling portion and the cylindrical portion.

[0006] Furthermore, the present invention provides a method for manufacturing a thrust bearing, the thrust bearing comprising: a first track disk having a track groove; a second track disk having a track groove; rolling elements disposed between the track grooves of the first track disk and the second track disk; and a retaining unit configured to cover the outer or inner peripheral surfaces of the first and second track disks and axially retaining the first and second track disks, the retaining unit comprising: a cylindrical portion facing the outer or inner peripheral surfaces of the first and second track disks. ; and a buckling portion, located at at least one end side of the axial end of the cylindrical portion, buckling around the entire circumference relative to the cylindrical portion, a chamfered portion is formed at the corner of the outer or inner circumferential surface of at least one of the first track disk and the second track disk, the chamfered portion facing the buckling portion of the retaining unit, and in the manufacturing method of the thrust bearing, the cylindrical portion and the buckling portion are formed into a cylindrical shape with the same cross section, a circumferential groove covering the entire circumference of the inner or outer circumferential surface is formed at the end portion of the cylindrical portion, and the buckling portion is formed by buckling and riveting at the circumferential groove.

[0007] The present invention provides a thrust bearing that can suppress bending of the retaining unit during riveting and accurately set the gap between the retaining unit and the track disk. Simple Explanation of the Diagram

[0008] Figure 1 is a cross-sectional view showing a thrust bearing according to a first embodiment of the present invention. Figure 2 is an enlarged cross-sectional view of the main parts of the thrust bearing in the embodiment. Figure 3 is a cross-sectional view showing the state of the cover before riveting in the first embodiment. Figure 4A is a cross-sectional view showing the state of the cover in the previous example before riveting, and Figure 4B is a cross-sectional view showing the cover after riveting. Figure 5A is a cross-sectional view showing the state of the cover before riveting in the modified example of the first embodiment, and Figure 5B is a cross-sectional view showing the cover after riveting. Figure 6A is a cross-sectional view showing the state of the cover in the thrust bearing of the second embodiment of the present invention before riveting, and Figure 6B is a cross-sectional view showing the cover after riveting. Figure 7A is a cross-sectional view showing the state of the cover before riveting in the modified example of the second embodiment, and Figure 7B is a cross-sectional view showing the cover after riveting. Implementation

[0009] 1. First Implementation Form A thrust bearing according to one embodiment of the present invention will be described with reference to Figures 1 to 4B. Furthermore, in the following description, "axial" refers to the direction of the central axis of the thrust bearing, and "radial" refers to the direction orthogonal to the axial direction. Additionally, "circumferential" refers to the direction of rotation about the central axis. Furthermore, terms indicating direction such as "up" and "down" refer to the up and down directions in Figure 1.

[0010] Figure 1 is a cross-sectional view of the thrust bearing 1 according to an embodiment. The thrust bearing 1 includes a first track disk 10 and a second track disk 20 arranged opposite to each other. The first track disk 10 and the second track disk 20 are annular, and on their mutually facing surfaces, track grooves 11 and 21 with arc-shaped cross-sections are formed over the entire circumference.

[0011] In the circular track ring formed by track grooves 11 and 21, a plurality of rolling elements 30 are arranged at equal intervals along the circumference. The rolling elements 30 are spherical, and the distance between adjacent rolling elements 30 is maintained at a constant level by a retainer (not shown).

[0012] A chamfered portion 12 is formed on the axially upper corner of the outer peripheral surface of the first track disk 10, covering the entire circumference. Similarly, a chamfered portion 22 is formed on the axially upper corner of the outer peripheral surface of the second track disk 20, covering the entire circumference. Covers (retaining units) 40 covering the outer peripheral surfaces of both the first track disk 10 and the second track disk 20 are installed.

[0013] The cover 40 is generally cylindrical and includes: a cylindrical portion 41 facing the outer peripheral surfaces of the first track disk 10 and the second track disk 20; and bent portions 42 and 43, which bend inward at the upper and lower axial ends of the cylindrical portion 41. The upper axial bent portion 42 faces the chamfered portion 12 of the first track disk 10, and the lower axial bent portion 43 faces the chamfered portion 22 of the second track disk 20. A peripheral groove 44 is formed at the boundary between the bent portion 42 and the cylindrical portion 41.

[0014] 2. Assembly method of thrust bearing First, the axially lower bent portion 43 of the cylindrical part of the cover 40 is formed. In this case, a circular blank is punched out from a flat plate, and the blank is deep-drawn into a cup shape with a conical portion at the corner that serves as the bent portion 43. Then, the inner side of the conical portion is punched to form the part of the cover 40 with the bent portion 43.

[0015] A plurality of rolling elements 30 (not shown) held by a retainer are placed in the track groove 21 of the second track disk 20, and the first track disk 10 is placed on it. The assembly is inserted into a part of the cover 40 having a bent portion 43. As shown in FIG3, a circumferential groove 44 is formed on the inner circumference of the axially upper end of the part of the cover 40.

[0016] The peripheral groove 44 has a V-shaped cross-section, and its depth d is set to 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 part of the peripheral groove 44 is rolled and riveted to form the buckled portion 42. In this way, the first track disk 10 and the second track disk 20 are in a state where they cannot be separated axially due to the buckled portions 42 and 43 of the cover 40.

[0017] 3. Effects In the thrust bearing 1 of the aforementioned structure, a circumferential groove 44 covering the entire inner circumference is formed at the boundary between the buckled portion 42 of the cover 40 and the cylindrical portion 41. Therefore, the bottom wall thickness of the circumferential groove 44 is thin. Consequently, during rolling riveting of the buckled portion 42, stress concentration occurs, causing the circumferential groove 44 to break, resulting in deformation by buckling at the circumferential groove 44. The rolling riveting then ends at the stage where the two inner surfaces of the V-shaped circumferential groove 44 are in close contact with each other. Therefore, as shown in FIG2, the cross-sectional shape of the buckled portion 42 is straight or approximately the same.

[0018] In contrast, as shown in Figure 4A, in the previous thrust bearing without the circumferential groove 44, when the buckling portion 42 is riveted and formed, stress is applied evenly to the portion that is the buckling portion 42. As shown in Figure 4B, the cross-sectional shape of the buckling portion 42 is curved, and the size of the gap between the buckling portion 42 and the first track disk 10 deviates.

[0019] Thus, in the thrust bearing 1 of the first embodiment, the bending of the buckling portion 42 during riveting can be suppressed and the buckling portion 42 can be set to a straight line or a shape similar to it, so the gap between the buckling portion 42 and the first track disk 10 can be accurately set.

[0020] In particular, in the first embodiment, the peripheral groove 44 before riveting is formed into a V-shaped cross section, and the two inner sides of the peripheral groove 44 are closely connected to each other after riveting. Therefore, by setting the opening angle of the peripheral groove 44, the angle formed by the buckling portion 42 and the cylindrical portion 41 can be set, and the gap between the front edge of the buckling portion 42 and the chamfered portion 12 of the first track disk 10 can be accurately set.

[0021] In addition, in the first embodiment, the depth d of the peripheral groove 44 is set to 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. Therefore, the strength of the cover 40 can be ensured, and the first track plate 10 and the second track plate 20 can be firmly connected.

[0022] In the first embodiment, the two inner sides of the peripheral groove 44 are in close contact with each other after riveting. However, as shown in Figures 5A and 5B, the opening angle of the peripheral groove 54 can also be set to be large, so that the cross-section of the peripheral groove 54 is V-shaped after riveting. Even in this case, the two inner sides of the peripheral groove 44 are in contact near their intersection (near the bottom of the peripheral groove 44). By increasing the load required for further buckling, the angle between the buckled portion 42 and the cylindrical portion 41 can be controlled, and the gap between the front edge of the buckled portion 42 and the chamfered portion 12 of the first track disk 10 can be accurately set.

[0023] 4. Second Implementation Form The second embodiment of the present invention will be described with reference to Figures 6A and 6B. In the second embodiment, the cross-sectional shape of the peripheral groove 64 before riveting is set to a semi-elliptical shape. In this peripheral groove 64, when the bent portion 42 is riveted, the axial edges of the two inner sides of the peripheral groove 64 are in close contact with each other after riveting. Therefore, in this second embodiment, by setting the interval between the axial edges of the inner sides of the peripheral groove 64, the angle formed by the bent portion 42 and the cylindrical portion 41 can also be set, and the gap between the front edge of the bent portion 42 and the chamfered portion 12 of the first track disk 10 can also be accurately set.

[0024] Figures 7A and 7B are diagrams illustrating a modified example of the second embodiment. In this modified example, the cross-sectional shape of the peripheral groove 74 before riveting is set to semi-circular. After riveting to form the buckled portion 42, the peripheral groove 74 also has an opening. Furthermore, the cross-sectional shape of the peripheral groove 74 can also be semi-elliptical or U-shaped.

[0025] 5. Example of Change The present invention is not limited to the described embodiments and can be modified in various ways as follows.

[0026] i) In the embodiment described above, the cover 40 is disposed on the outer peripheral side of the first track disk 10 and the second track disk 20, but may be disposed on the inner peripheral side. In this case, chamfered portions are formed at the corners of the axial ends of the inner peripheral surfaces of the first track disk 10 and the second track disk 20, and buckled portions facing the chamfered portions are formed at both ends of the cover.

[0027] ii) The rolling element 30 is not limited to a spherical rolling element; a cylindrical or frustum-shaped rolling element may be used.

[0028] iii) In the aforementioned embodiment, arc-shaped track grooves 11 and 21 are formed on the entire circumference of the first track disk 10 and the second track disk 20. However, a spherical recess supporting the rolling element 30 can be formed on the second track disk 20, and a flat surface facing the first track disk 10 can be formed thereon. The same applies when the rolling element 30 is cylindrical or frustum conical. [Industry availability]

[0029] This invention can be used in all thrust bearings, such as steering pin thrust bearings used in suspensions of automobiles, etc., or bolts that reduce torque during tightening by fixing one of the track discs to the head.

[0030] 1: Thrust bearing 10: First Track Disc 20: Second track disk 11, 21: Track groove 30: Rolling element 12, 22: Chamfered section 40: Cover / Retaining Unit 41: Cylindrical section 42, 43: Flexion part 44, 54, 64, 74: Zhou Cao d: depth

Claims

1. A thrust bearing, comprising: The first track plate has track grooves; The second track plate has track grooves; A rolling element is disposed between the track groove of the first track disk and the track groove of the second track disk; and a retaining unit is disposed to cover the outer or inner circumferential surfaces of the first and second track disks and to retain the first and second track disks axially. The retaining unit has: a cylindrical portion facing the outer or inner circumferential surface of the first and second track disks; and a buckling portion located at at least one end of the axial end of the cylindrical portion, buckling circumferentially relative to the cylindrical portion, and a chamfered portion is formed at the corner of the outer or inner circumferential surface of at least one of the first and second track disks. In the thrust bearing facing the buckling portion of the retaining unit, a circumferential groove is formed at the boundary between the buckling portion and the cylindrical portion, extending circumferentially over the inner or outer circumferential surface. At least a portion of the inner surface of one axial side of the circumferential groove contacts the inner surface of the other axial side, while other portions do not contact each other.

2. The thrust bearing as described in claim 1, wherein, The depth of the circumferential groove is less than 1 / 2 of the thickness of the cylindrical portion of the retaining unit.

3. The thrust bearing as described in claim 2, wherein, The depth of the circumferential groove is less than 1 / 3 of the thickness of the cylindrical portion of the retaining unit.

4. The thrust bearing as claimed in any one of claims 1 to 3, wherein, The two inner surfaces contact the bottom of the circumferential groove.

5. The thrust bearing as claimed in any one of claims 1 to 3, wherein, The cross-section of the peripheral groove is approximately V-shaped.

6. The thrust bearing as claimed in any one of claims 1 to 3, wherein, The peripheral groove has a generally elongated oval cross section, and the end edge of the inner side of one axial side of the peripheral groove is in contact with the end edge of the inner side of the other axial side.

7. The thrust bearing as claimed in any one of claims 1 to 3, wherein, The cross-section of the peripheral groove is roughly U-shaped.

8. A method for manufacturing a thrust bearing, the thrust bearing comprising: The first track plate has track grooves; The second track plate has track grooves; A rolling element is disposed between the track groove of the first track disk and the track groove of the second track disk; and a retaining unit is disposed to cover the outer or inner circumferential surfaces of the first and second track disks and to retain the first and second track disks axially. The retaining unit has: a cylindrical portion facing the outer or inner circumferential surface of the first and second track disks; and a buckling portion located at at least one end side of the axial end of the cylindrical portion, buckling around the entire circumference relative to the cylindrical portion, and a chamfered portion is formed at the corner of the outer or inner circumferential surface of at least one of the first and second track disks, the chamfered portion facing the buckling portion of the retaining unit. In the manufacturing method of the thrust bearing, the cylindrical portion and the buckling portion are formed into a cylindrical shape with the same cross-section, a circumferential groove covering the entire circumference of the inner or outer circumferential surface is formed at the end portion of the cylindrical portion, and the buckling portion is formed by buckling and riveting at the circumferential groove.

9. A method for manufacturing a thrust bearing as described in claim 8, wherein, In the riveting process, at least a portion of the inner surface of one axial side of the circumferential groove is in contact with the inner surface of the other axial side.

10. A method for manufacturing a thrust bearing as described in claim 8, wherein, The inner surface of one side of the axial groove is in contact with the entire inner surface of the other side of the axial groove.

11. A method for manufacturing a thrust bearing as described in claim 8, wherein, The inner surface of one side of the axial groove is separated from the inner surface of the other side of the axial groove, so that the cross-section of the riveted circumferential groove is approximately V-shaped.

12. A method for manufacturing a thrust bearing as described in claim 8, wherein, The cross-section of the peripheral groove is approximately semi-circular or approximately U-shaped, such that the end edge of the inner side of one axial side of the peripheral groove is in contact with the end edge of the inner side of the other axial side.

13. A method for manufacturing a thrust bearing as described in claim 8, wherein, The cross-section of the peripheral groove is approximately semi-circular or approximately U-shaped, such that the end edge of the inner side of one axial side of the peripheral groove is separated from the end edge of the inner side of the other axial side.

Images