Thrust bearing

Abstract

To provide a thrust bearing which can inhibit curving of a cover during swaging to enable a gap to be set accurately between the cover and a raceway disk.SOLUTION: A thrust bearing 1 includes a cover 40 which is arranged so as to cover outer peripheral surfaces of a first raceway disk 10 and a second raceway disk and holds the first raceway disk 10 and the second raceway disk in an axial direction. The cover 40 has: a cylindrical part 41 facing the outer peripheral surfaces of the first raceway disk 10 and the second raceway disk; and a bending part 42 provided in at least one axial end of the cylindrical part 41 and bending over an entire periphery relative to the cylindrical part 41. A chamfered part 12 is formed at a corner part of the outer peripheral surface of at least one of the first raceway disk 10 and the second raceway disk, and the chamfered part 12 and the bending part 42 of the cover 40 face each other. A peripheral groove 44 ranging an entire periphery of an inner peripheral surface is formed at a border part between the bending part 42 and the cylindrical part 41.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a thrust bearing, and more particularly to an improvement in a cover that connects a first washer and a second washer. [Background technology]

[0002] A thrust bearing is a bearing in which rolling elements are disposed between a first washer and a second washer and which receives a thrust load. In order to prevent the first washer and the second washer from separating, a cover may be disposed to cover the outer periphery of both washers (see, for example, Patent Document 1 and Patent Document 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 8-004759 [Patent Document 2] Japanese Patent Application Publication No. 2020-143708 Summary of the Invention [Problem to be solved by the invention]

[0004] The cover has a shape that prevents the bearing washer from separating by bending the end of its cylindrical portion to form a portion that faces the chamfered portion at the corner of the bearing washer. However, when the end of the cylindrical portion is crimped, the cover may bend, which causes the gap between the cover and bearing washer to vary.

[0005] The present invention has been made in consideration of the above circumstances, and aims to provide a thrust bearing that can suppress bending of the cover when crimped and accurately set the gap between the cover and the bearing washer. [Means for solving the problem]

[0006] The present invention provides a first bearing washer having a raceway groove; a second bearing washer having a raceway groove; rolling elements arranged between the raceway groove of the first bearing washer and the raceway groove of the second bearing washer; and retaining means arranged to cover the outer peripheral surface or the inner peripheral surface of the first bearing washer and the second bearing washer, and for retaining the first bearing washer and the second bearing washer in the axial direction, the retaining means has a cylindrical portion facing an outer peripheral surface or an inner peripheral surface of the first bearing washer and the second bearing washer, and a bent portion bent over the entire circumference of the cylindrical portion at at least one of axial end portions of the cylindrical portion, In a thrust bearing in which a chamfered portion is formed at a corner of an outer peripheral surface or an inner peripheral surface of at least one of the first washer and the second washer, and the chamfered portion faces the bent portion of the retaining means, A circumferential groove is formed along the entire circumference of the inner or outer circumferential surface at the boundary between the bent portion and the cylindrical portion. 、 A part of the inner surface of one axial direction of the circumferential groove and a part of the inner surface of the other axial direction of the circumferential groove are in contact with each other, and the other part is not in contact with each other. It is a thrust bearing.

[0007] The present invention also provides a first bearing washer having a raceway groove; a second bearing washer having a raceway groove; rolling elements arranged between the raceway groove of the first bearing washer and the raceway groove of the second bearing washer; and retaining means arranged to cover the outer peripheral surface or the inner peripheral surface of the first bearing washer and the second bearing washer, and for retaining the first bearing washer and the second bearing washer in the axial direction, the retaining means has a cylindrical portion facing an outer peripheral surface or an inner peripheral surface of the first bearing washer and the second bearing washer, and a bent portion bent over the entire circumference of the cylindrical portion on at least one side of an axial end of the cylindrical portion, a chamfered portion is formed at a corner of an outer peripheral surface or an inner peripheral surface of at least one of the first bearing washer and the second bearing washer, and the chamfered portion faces the bent portion of the retaining means, The cylindrical portion and the bent portion are formed into a cylindrical shape with a uniform cross section, and a circumferential groove is formed at an end portion of the cylindrical portion over the entire circumference of the inner circumferential surface or the outer circumferential surface, a part of an inner surface of one axial direction of the circumferential groove and a part of an inner surface of the other axial direction of the circumferential groove are in contact with each other, and another part is not in contact with each other; This is a method for manufacturing a thrust bearing, in which the bearing is bent at the circumferential groove and the bent portion is crimped. [Effects of the Invention]

[0008] According to the present invention, a thrust bearing is provided in which bending of the retaining means during crimping can be suppressed and the gap between the retaining means and the bearing washer can be accurately set. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view showing a thrust bearing according to a first embodiment of the present invention. [Figure 2] FIG. 2 is an enlarged cross-sectional view showing a main part of the thrust bearing according to the embodiment. [Figure 3] 4 is a cross-sectional view showing a state before the cover in the first embodiment is crimped. FIG. [Figure 4] 1A is a cross-sectional view showing a state of a conventional cover before crimping, and FIG. 1B is a cross-sectional view showing the cover after crimping. [Figure 5] 10(A) is a cross-sectional view showing a state before crimping of a cover in a modified example of the first embodiment, and FIG. 10(B) is a cross-sectional view showing the cover after crimping. [Figure 6] 10(A) is a cross-sectional view showing a state before a cover of a thrust bearing according to a second embodiment of the present invention is crimped, and FIG. 10(B) is a cross-sectional view showing the cover after crimping. [Figure 7] 10(A) is a cross-sectional view showing a state before crimping of a cover in a modified example of the second embodiment, and FIG. 10(B) is a cross-sectional view showing the cover after crimping. DETAILED DESCRIPTION OF THE INVENTION

[0010] 1. First embodiment A thrust bearing according to one embodiment of the present invention will be described with reference to Figures 1 to 4. In the following description, "axial direction" refers to the direction of the central axis of the thrust bearing, and "radial direction" refers to the direction perpendicular to the axial direction. Furthermore, "circumferential direction" refers to the direction of rotation around the central axis. Furthermore, terms indicating directions such as "up" and "down" refer to the up and down directions in Figure 1.

[0011] Figure 1 is a cross-sectional view showing a thrust bearing 1 according to an embodiment. The thrust bearing 1 comprises a first washer 10 and a second washer 20 arranged opposite each other. The first washer 10 and the second washer 20 are annular, and raceway grooves 11 and 21, each having an arc-shaped cross section, are formed around the entire circumference on the opposing surfaces of the first washer 10 and the second washer 20.

[0012] A plurality of rolling elements 30 are arranged at equal intervals in the circumferential direction on a raceway ring having a circular cross section formed by raceway grooves 11 and 21. The rolling elements 30 are spherical, and the distance between adjacent rolling elements 30 is kept constant by a cage (not shown).

[0013] A chamfered portion 12 is formed around the entire periphery at an upper axial corner of the outer peripheral surface of the first bearing washer 10. Furthermore, a chamfered portion 22 is formed around the entire periphery at an upper axial corner of the outer peripheral surface of the second bearing washer 20. A cover (retaining means) 40 that covers the outer peripheral surfaces of the first bearing washer 10 and the second bearing washer 20 is attached.

[0014] The cover 40 is substantially cylindrical and comprises a cylindrical portion 41 that faces the outer peripheral surfaces of the first and second bearing washer 10 and 20, and bent portions 42, 43 that are bent inward at the upper and lower axial ends of the cylindrical portion 41. The bent portion 42 on the upper axial side faces the chamfered portion 12 of the first bearing washer 10, and the bent portion 43 on the lower axial side faces the chamfered portion 22 of the second bearing washer 20. A circumferential groove 44 is formed at the boundary between the bent portion 42 and the cylindrical portion 41.

[0015] 2. Thrust bearing assembly method First, the bent portion 43 is formed on the axially lower side of the cylindrically formed part of the cover 40. In this case, a disk-shaped blank is punched out from a flat plate, and the blank is drawn into a cup shape having tapered corners that become the bent portion 43. Next, the inside of the tapered portion is punched out to form the part of the cover 40 having the bent portion 43.

[0016] A plurality of rolling elements 30 held in a cage (not shown) are placed in the raceway grooves 21 of the second bearing washer 20, and then the first bearing washer 10 is placed on top of that. This assembly is inserted into the cover 40 part, which has a bent portion 43 formed in it. As shown in Figure 3, a circumferential groove 44 is formed around the entire inner periphery of the axially upper end of the cover 40 part.

[0017] The circumferential groove 44 has a V-shaped cross section, and its depth is equal to or less than ½ the thickness of the cylindrical portion 41 of the cover 40, and preferably equal to or less than ⅓ the thickness of the cylindrical portion 41. The outer peripheral surface of the upper portion of the circumferential groove 44 is then roll-swaged to form the bent portion 42. As a result, the first and second bearing washer 10 and 20 cannot be separated in the axial direction due to the bent portions 42, 43 of the cover 40.

[0018] 3.Effects In thrust bearing 1 configured as described above, a circumferential groove 44 is formed around the entire inner periphery at the boundary between bent portion 42 and cylindrical portion 41 of cover 40. Because the thickness of the bottom of circumferential groove 44 is thin, stress concentrates when bent portion 42 is roll-swaged, causing circumferential groove 44 to collapse and deform so as to bend at circumferential groove 44. Roll-swaging then ends when the two inner surfaces of circumferential groove 44, which has a V-shaped cross section, come into close contact with each other. Therefore, as shown in FIG. 2, the cross-sectional shape of bent portion 42 is linear or a shape similar to that.

[0019] In contrast, in a conventional thrust bearing that does not have a circumferential groove 44 as shown in Figure 4(A), when the bent portion 42 is crimped, stress acts evenly on the part that will become the bent portion 42, and as shown in Figure 4(B), the cross-sectional shape of the bent portion 42 becomes curved, resulting in variation in the size of the gap between the bent portion 42 and the first bearing washer 10.

[0020] In this way, in the thrust bearing 1 of the first embodiment described above, the bending of the bent portion 42 during crimping can be suppressed, and the bent portion 42 can be made straight or have a shape similar to that, so that the gap between the bent portion 42 and the first bearing washer 10 can be accurately set.

[0021] In particular, in the first embodiment described above, the circumferential groove 44 is formed to have a V-shaped cross section before crimping, and the two inner surfaces of the circumferential groove 44 are made to adhere to each other after crimping. Therefore, by setting the opening angle of the circumferential groove 44, the angle between the bent portion 42 and the cylindrical portion 41 can be set, and the gap between the tip edge of the bent portion 42 and the chamfered portion 12 of the first bearing washer 10 can be accurately set.

[0022] Furthermore, in the first embodiment described above, the depth of the circumferential groove 44 is set to ½ or less of the thickness of the cylindrical portion 41 of the cover 40, and preferably ⅓ or less of the thickness of the cylindrical portion 41, thereby ensuring the strength of the cover 40 and enabling the first bearing washer 10 and the second bearing washer 20 to be firmly joined together.

[0023] In the first embodiment described above, the two inner surfaces of the circumferential groove 44 are in close contact with each other after crimping, but as shown in Fig. 5, the opening angle of the circumferential groove 54 may be set large so that the circumferential groove 54 has a V-shaped cross section after crimping. Even in this case, the two inner surfaces of the circumferential groove 44 come into contact near their intersection (near the bottom of the circumferential groove 44), and the load required for further bending increases, making it possible to control the angle between the bending portion 42 and the cylindrical portion 41 and accurately set the gap between the leading edge of the bending portion 42 and the chamfered portion 12 of the first bearing washer 10.

[0024] 4. Second embodiment A second embodiment of the present invention will be described with reference to Figure 6. In the second embodiment, the cross-sectional shape of the circumferential groove 64 before crimping is semi-elliptical. In such a circumferential groove 64, when the bent portion 42 is crimped, the axial edge portions of the two inner surfaces of the circumferential groove 64 come into close contact with each other after crimping. Therefore, in this second embodiment as well, by setting the distance between the axial edge portions of the inner surfaces of the circumferential groove 64, it is possible to set the angle between the bent portion 42 and the cylindrical portion 41 and accurately set the gap between the leading edge of the bent portion 42 and the chamfered portion 12 of the first bearing washer 10.

[0025] 7 is a diagram showing a modification of the second embodiment. In this modification, the cross-sectional shape of the circumferential groove 74 before crimping is semicircular. The circumferential groove 74 remains open even after the bent portion 42 is crimped. The cross-sectional shape of the circumferential groove 74 may also be semi-elliptical or U-shaped.

[0026] 5. Example of changes The present invention is not limited to the above-described embodiment, and various modifications are possible as follows. i) In the above embodiment, the cover 40 is provided on the outer peripheral side of the first bearing washer 10 and the second bearing washer 20, but it can also be provided on the inner peripheral side. In that case, chamfered portions are formed at the corners of both axial ends of the inner peripheral surfaces of the first bearing washer 10 and the second bearing washer 20, and bent portions are formed at both ends of the cover so as to face the chamfered portions.

[0027] ii) The rolling elements 30 are not limited to those having a spherical shape, but may have a cylindrical or truncated conical shape. iii) In the above embodiment, the raceway grooves 11, 21 having an arc-shaped cross section are formed over the entire circumference of the first and second races 10, 20, but it is also possible to form a spherical recess in the second race 20 to support the rolling elements 30, and form the opposing surface of the first race 10 flat. The same applies when the rolling elements 30 are cylindrical or truncated cone-shaped. [Industrial Applicability]

[0028] The present invention can be used in all types of thrust bearings, such as kingpin thrust bearings used in suspensions of automobiles, and bolts in which one of the washers is fixed to the head to reduce torque during tightening. [Explanation of symbols]

[0029] 1... thrust bearing, 10... first washer, 20... second washer, 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 first bearing washer having a raceway groove; a second bearing washer having a raceway groove; rolling elements arranged between the raceway groove of the first bearing washer and the raceway groove of the second bearing washer; and retaining means arranged to cover the outer peripheral surface or the inner peripheral surface of the first bearing washer and the second bearing washer, and for retaining the first bearing washer and the second bearing washer in the axial direction, the retaining means has a cylindrical portion facing an outer peripheral surface or an inner peripheral surface of the first bearing washer and the second bearing washer, and a bent portion bent over the entire circumference of the cylindrical portion at at least one of axial end portions of the cylindrical portion, In a thrust bearing in which a chamfered portion is formed at a corner of an outer peripheral surface or an inner peripheral surface of at least one of the first washer and the second washer, and the chamfered portion faces the bent portion of the retaining means, a circumferential groove is formed along the entire periphery of the inner or outer circumferential surface at the boundary between the bent portion and the cylindrical portion; A thrust bearing in which a portion of the inner surface of one axial direction of the circumferential groove and a portion of the inner surface of the other axial direction of the circumferential groove are in contact with each other, and the other portion is not in contact with each other.

2. 2. A thrust bearing according to claim 1, wherein the depth of said circumferential groove is equal to or less than half the thickness of said cylindrical portion of said retaining means.

3. 3. A thrust bearing according to claim 2, wherein the depth of said circumferential groove is equal to or less than one-third of the thickness of said cylindrical portion of said retaining means.

4. A thrust bearing described in any one of claims 1 to 3, wherein the two inner surfaces are in contact with each other at the bottom side of the circumferential groove.

5. a first bearing washer having a raceway groove; a second bearing washer having a raceway groove; rolling elements arranged between the raceway groove of the first bearing washer and the raceway groove of the second bearing washer; and retaining means arranged to cover the outer peripheral surface or the inner peripheral surface of the first bearing washer and the second bearing washer, and for retaining the first bearing washer and the second bearing washer in the axial direction, the retaining means has a cylindrical portion facing an outer peripheral surface or an inner peripheral surface of the first bearing washer and the second bearing washer, and a bent portion bent over the entire circumference of the cylindrical portion on at least one side of an axial end of the cylindrical portion, a chamfered portion is formed at a corner of an outer peripheral surface or an inner peripheral surface of at least one of the first bearing washer and the second bearing washer, and the chamfered portion faces the bent portion of the retaining means, A method for manufacturing a thrust bearing, comprising forming the cylindrical portion and the bent portion into a cylindrical shape with a uniform cross section, forming a circumferential groove around the entire circumference of the inner or outer surface at the end of the cylindrical portion, and bending the bent portion at the circumferential groove so that part of the inner surface on one axial side of the circumferential groove and part of the inner surface on the other axial side are in contact with each other, and other parts are not in contact with each other.

6. 6. The method for manufacturing a thrust bearing according to claim 5, wherein the two inner surfaces are brought into contact with each other at the bottom side of the circumferential groove during the crimping process.

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