Crown retainer and ball bearing

Abstract

The crown-shaped retainer includes a circular ring portion and a plurality of column portions protruding from the ring portion to one side in the axial direction and arranged in the circumferential direction. A pocket in which one of the plurality of balls is arranged is formed between adjacent column portions. The inner surface of the pocket extends along a cylinder having a central axis parallel to the radial direction. A protrusion protruding inward or outward in the radial direction is formed on at least a portion of the ring portion corresponding to the bottom of the pocket.

Description

Technical Field

[0001] One aspect of the present disclosure relates to a crown-type cage and a ball bearing. Background Art

[0002] Patent Document 1 describes a crown-shaped retainer, which includes an annular portion and a plurality of columnar portions arranged at intervals in the circumferential direction on one side of the annular portion in the axial direction, and has spherical pockets formed by the columnar portions and the annular portion adjacent in the circumferential direction to retain a plurality of balls. The crown-shaped retainer is used for ball bearings.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Utility Model Registration No. 3210224 Summary of the invention

[0006] Problems to be solved by the invention

[0007] When using the ball bearings described above, the retainer rotates at high speed. At this time, the tip of the column deforms radially outward due to centrifugal force, which sometimes generates stress at the bottom of the pocket. In this case, the retainer may be damaged due to interference between the tip of the deformed column and the outer ring or stress. From the perspective of reliability, it is required to suppress such a situation.

[0008] Therefore, an object of one aspect of the present disclosure is to provide a crown-type cage and a ball bearing having improved reliability.

[0009] Solutions to Solve Problems

[0010] A crown-shaped retainer according to one embodiment of the present invention is [1] "a crown-shaped retainer for retaining a plurality of balls arranged along a circumferential direction so as to be able to roll freely, the crown-shaped retainer comprising: an annular ring portion; and a plurality of column portions, which protrude axially from the ring portion and are arranged along the circumferential direction, a pocket in which one of the plurality of balls is arranged is formed between adjacent column portions, the inner surface of the pocket extending along a cylinder having a central axis parallel to the radial direction, and a protrusion protruding radially inward or outward is formed on at least a portion of the ring portion corresponding to the bottom of the pocket".

[0011] In the crown-type retainer, the inner surface of the pocket extends along a cylinder having a central axis parallel to the radial direction. A crown-type retainer having such a cylindrical pocket can be used for bearings that are not ball-guided (rolling element-guided) but outer ring-guided or inner ring-guided. In the case where the pocket is cylindrical, the column portion is unlikely to interfere with the ball even when deformed by centrifugal force. On the other hand, in the case where the pocket is cylindrical, for example, compared with a spherical pocket, when the retainer rotates at high speed, deformation caused by centrifugal force is likely to occur in the column portion. In this regard, in the crown-type retainer, a protrusion protruding radially inward or outward is formed on at least the portion of the ring portion corresponding to the bottom of the pocket. As a result, the rigidity of the crown-type retainer can be improved, and deformation caused by centrifugal force can be suppressed. Therefore, according to the crown-type retainer, reliability can be improved.

[0012] A crown-shaped retainer according to one aspect of the present disclosure may also be [2] "a crown-shaped retainer according to [1], wherein the crown-shaped retainer is formed of a resin material". In this case, the crown-shaped retainer can be manufactured, for example, by injection molding using a resin material, which can facilitate manufacturing. In addition, since a protrusion is formed on at least a portion of the ring portion corresponding to the bottom of the pocket, the portion can be formed into a thick wall, and the welding position can be easily avoided from the portion during injection molding. As a result, the occurrence of a situation in which the strength of the portion is reduced due to the welding position being located in the portion can be suppressed, and reliability can be further improved.

[0013] A crown-shaped retainer according to one embodiment of the present disclosure may also be [3] "the crown-shaped retainer according to [1] or [2], wherein the protrusion is formed only on a portion of the ring portion corresponding to the bottom of the pocket". In this case, the rigidity of the portion of the ring portion corresponding to the bottom of the pocket can be increased, and deformation caused by centrifugal force can be suppressed.

[0014] The crown-shaped cage of one aspect of the present disclosure may be [4] "the crown-shaped cage according to any one of [1] to [3], wherein the protrusion protrudes radially inward from the ring portion." In this case, the rigidity of the crown-shaped cage can be increased, and deformation due to centrifugal force can be suppressed.

[0015] The crown-shaped cage of one aspect of the present disclosure may be [5] "the crown-shaped cage according to any one of [1] to [3], wherein the protrusion protrudes radially outward from the ring portion." In this case, the rigidity of the crown-shaped cage can be increased, and deformation due to centrifugal force can be suppressed.

[0016] A ball bearing according to one embodiment of the present disclosure is [6] "a ball bearing comprising: an inner ring; an outer ring; the plurality of balls arranged between the inner ring and the outer ring; and a crown-shaped retainer according to any one of [1] to [5] for retaining the plurality of balls so as to be able to roll freely". In this ball bearing, reliability can be improved for the above reasons.

[0017] Effects of the Invention

[0018] According to the present disclosure, it is possible to provide a crown-type cage and a ball bearing having improved reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a cross-sectional view of the ball bearing according to the embodiment.

[0020] Figure 2 It is a perspective view of the retainer according to the embodiment.

[0021] Figure 3 It is a cross-sectional view of a ball bearing according to a modified example.

[0022] Figure 4 It is a perspective view of a cage according to a modified example. DETAILED DESCRIPTION

[0023] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In the following description, the same reference numerals are used for the same or corresponding elements, and repeated descriptions are omitted.

[0024] like Figure 1 As shown, the ball bearing 1 has an inner ring 2, an outer ring 3, a plurality of balls 5 and a retainer 10 (crown retainer). The ball bearing 1 is used, for example, in an electric compressor to support a rotor. Hereinafter, the direction parallel to the center line A of the ball bearing 1 is referred to as the axial direction, the direction perpendicular to the center line A is referred to as the radial direction, and the direction along the circumference of the circle centered on the center line A when viewed from a direction parallel to the center line A is referred to as the circumferential direction.

[0025] The inner ring 2 is formed in an annular shape and has an inner ring raceway surface 2a. The inner ring raceway surface 2a is a surface facing radially outward and extending in an annular shape along the circumferential direction. The inner ring raceway surface 2a is formed in a shape corresponding to the ball 5. The inner ring 2 is fitted with a shaft (not shown) on the radially inner side, for example.

[0026] The outer ring 3 is formed in an annular shape and is arranged on the outer side of the inner ring 2 in the radial direction. The outer ring 3 has an outer ring raceway surface 3a and a guide surface 3b. The outer ring raceway surface 3a and the guide surface 3b are surfaces facing the inner side in the radial direction and extending in an annular shape along the circumferential direction. The outer ring raceway surface 3a is formed in a shape corresponding to the ball 5. The guide surface 3b is composed of, for example, a pair of surfaces (a pair of surfaces extending in an annular shape along the circumferential direction) located on both sides of the outer ring raceway surface 3a in the axial direction. The outer ring 3 is, for example, fitted with a housing (not shown) on the outer side in the radial direction.

[0027] The plurality of balls 5 are each formed in a spherical shape. The plurality of balls 5 are arranged between the inner ring raceway surface 2a and the outer ring raceway surface 3a. The plurality of balls 5 are held by a retainer 10 and arranged in a row at predetermined intervals in the circumferential direction.

[0028] The retainer 10 is arranged between the inner ring raceway surface 2a of the inner ring 2 and the outer ring raceway surface 3a of the outer ring 3, and retains the plurality of balls 5 so that they can roll freely. In this example, the retainer 10 is guided by the guide surface 3b of the outer ring 3. That is, the ball bearing 1 is configured as a bearing guided by the outer ring. The retainer 10 is, for example, a crown-shaped retainer made of a resin material. The retainer 10 is formed, for example, by injection molding using a resin material. The retainer 10 has a plurality of (seven in this example) pockets 20. A plurality of balls 5 are respectively arranged in the plurality of pockets 20.

[0029] like Figure 2 As shown, the retainer 10 has a ring portion 11 and a plurality of (seven in this example) column portions 12. The ring portion 11 is formed in a circular ring shape. Each column portion 12 extends from the ring portion 11 to one side in the axial direction ( Figure 2 The plurality of column portions 12 are arranged at predetermined intervals in the circumferential direction. The pockets 20 are formed between adjacent column portions 12. The pockets 20 are defined by a pair of adjacent column portions 12 and a portion 11a of the ring portion 11 extending therebetween.

[0030] Each column portion 12 has a main body portion 13 and a pair of claw portions 14. The main body portion 13 protrudes from the ring portion 11 to one side in the axial direction. The pair of claw portions 14 protrude from the main body portion 13 to one side in the axial direction. The pair of claw portions 14 includes a claw portion 14a arranged on one side in the circumferential direction and a claw portion 14b arranged on the other side in the circumferential direction. The claw portion 14a extends in a manner that the farther away from the main body portion 13, the more toward one side in the circumferential direction, and the claw portion 14b extends in a manner that the farther away from the main body portion 13, the more toward the other side in the circumferential direction. The main body portion 13 and the pair of claw portions 14 define a pocket 20. The pair of claw portions 14 suppress the axial fall-off of the ball 5 arranged in the pocket 20.

[0031] The pocket 20 is formed in a cylindrical shape. Specifically, the inner surface 20a of the pocket 20 extends along a cylinder having a central axis parallel to the radial direction. As described above, the pocket 20 is divided by a portion 11a of the ring portion 11, the main body 13 of the column portion 12, and a pair of claws 14. The portion 11a of the ring portion 11 divides the bottom 21 of the pocket 20. That is, the portion 11a is the portion of the ring portion 11 corresponding to the bottom 21 of the pocket 20. "The portion of the ring portion 11 corresponding to the bottom 21" refers to, for example, the portion of the ring portion 11 that divides the bottom 21 and overlaps with the bottom 21 when viewed from the axial direction.

[0032] A protrusion 15 protruding radially inward is formed on a portion 11a of the ring portion 11. The protrusion 15 is formed on the inner circumferential surface of the ring portion 11. The protrusion 15 is formed only on a portion 11a of the ring portion 11, and is not formed on other portions of the ring portion 11 (e.g., a connection portion with the column portion 12). The retainer 10 has a plurality of (seven in this example) protrusions 15. The plurality of protrusions 15 are formed so as to be arranged at predetermined intervals in the circumferential direction.

[0033] In the axial direction, the protrusion 15 is formed between the bottom 21 of the pocket 20 and the surface of the ring portion 11 on the opposite side of the pocket 20. The protrusion 15 has a curved surface 15a that is continuous with the bottom 21 of the pocket 20. The length of the protrusion 15 in the circumferential direction is shorter than the length of the pocket 20 in the circumferential direction. In this example, a pair of side surfaces 15b of the protrusion 15 in the circumferential direction are inclined surfaces that are inclined closer to each other as they approach the center line A (towards the inner side in the radial direction). The length of the protrusion 15 in the radial direction is shorter than the length of the ring portion 11 in the radial direction.

[0034] [Function and Effect]

[0035] In the retainer 10, the inner surface 20a of the pocket 20 extends along a cylinder having a central axis parallel to the radial direction. The retainer 10 having such a cylindrical pocket 20 can be used for a bearing that is not ball-guided (rolling element-guided) but outer ring-guided or inner ring-guided. In the case where the pocket is cylindrical, the column portion is unlikely to interfere with the ball even when deformed by centrifugal force. On the other hand, in the case where the pocket 20 is cylindrical, for example, compared with the case where the pocket 20 is spherical, when the retainer 10 rotates at a high speed, the column portion 12 (claw portion 14) is easily deformed by centrifugal force. In this regard, in the retainer 10, a protrusion 15 protruding inward in the radial direction is formed on a portion 11a of the ring portion 11 (a portion corresponding to the bottom 21 of the pocket 20). As a result, the rigidity of the retainer 10 can be improved. That is, the rigidity of the portion 11a of the ring portion 11 can be improved, and the rigidity of the retainer 10 as a whole can be improved. As a result, the deformation of the retainer 10 caused by the centrifugal force can be suppressed. Therefore, according to the retainer 10 , the reliability can be improved.

[0036] The retainer 10 is formed of a resin material. Thus, for example, the retainer 10 can be manufactured by injection molding using a resin material, and manufacturing can be facilitated. In addition, since the protrusion 15 is formed on the portion 11a of the ring portion 11, the portion 11a can be formed thick, and the welding position can be easily avoided from the portion 11a during injection molding. As a result, it is possible to suppress the occurrence of a situation in which the strength of the portion 11a is reduced due to the welding position being located at the portion 11a, and reliability can be further improved.

[0037] That is, when the protrusion 15 is not formed, the difference (difference in wall thickness) between the cross-sectional area of ​​the portion 11a of the ring portion 11 (the area of ​​the cross section perpendicular to the circumferential direction) and the cross-sectional area of ​​the portion of the ring portion 11 connected to the column portion 12 (the area of ​​the cross section perpendicular to the circumferential direction) becomes larger. In this case, since the cross-sectional area of ​​the portion 11a is small, when the molten resin is flowed into the mold during injection molding, the flow speed of the resin in the portion corresponding to the portion 11a becomes slow. Therefore, the welding position (the position where the resin flowing into the mold merges) is likely to be located at the portion 11a of the ring portion 11. In other words, it is difficult to change the injection gate position or the injection conditions to adjust the welding position to be located at a portion other than the portion 11a of the ring portion 11. At the welding position, the resins are difficult to fuse with each other, and the strength after molding is likely to decrease. In the retainer 10, since the portion 11a of the ring portion 11 is the thinnest and weakest portion, if the welding position is located at the portion 11a of the ring portion 11, the strength of the portion 11a is further reduced. In this regard, in the retainer 10, since the protrusion 15 is formed on the portion 11a of the ring portion 11, the portion 11a can be formed thick (the cross-sectional area of ​​the portion 11a can be increased), and the welding position can be easily avoided from the portion 11a during injection molding. As a result, it is possible to suppress the occurrence of a situation where the strength of the portion 11a is reduced due to the welding position being located at the portion 11a, and the reliability can be further improved.

[0038] The protrusion 15 is formed only on a portion 11a of the ring portion 11. This can improve the rigidity of the portion 11a of the ring portion 11 and suppress deformation due to centrifugal force. In addition, it is easier to avoid the weld position from the portion 11a during injection molding.

[0039] The projections 15 project radially inward from the ring portion 11. This can improve the rigidity of the cage 10 and suppress deformation due to centrifugal force.

[0040] [Modifications]

[0041] exist Figure 3 and Figure 4In the modified example shown, the protrusion 15 protrudes radially outward from a portion 11a of the ring portion 11. In this modified example, the retainer 10 is guided by the outer ring 3 at the protrusion 15. More specifically, the radially outer surface 15c of the protrusion 15 serves as a guide surface for the outer ring 3, and the surface 15c is guided by the guide surface 3b of the outer ring 3. With such a modified example, the reliability can be improved in the same manner as in the above-mentioned embodiment. In addition, by the protrusion 15 serving as a guide surface for the outer ring 3, the contact area between the retainer 10 and the outer ring 3 can be reduced, and the friction generated between the retainer 10 and the outer ring 3 can be reduced (low friction effect).

[0042] The present disclosure is not limited to the above-described embodiments and modifications. For example, the materials and shapes of each structure are not limited to the above-described materials and shapes, and various materials and shapes can be adopted. The holder 10 may be formed of a material other than a resin material.

[0043] In the above embodiment, the protrusion 15 is formed only on the part 11a of the ring portion 11, but the protrusion 15 only needs to be formed on at least the part of the ring portion 11 corresponding to the bottom 21 of the pocket 20, and for example, it may be formed on the entire circumference of the ring portion 11, or may be formed from the part 11a to the connecting part of the ring portion 11 and the column portion 12. Both a protrusion protruding radially inward and a protrusion protruding radially outward may be formed on the part 11a of the ring portion 11.

[0044] The ball bearing 1 may be configured as an inner ring guided bearing. In this case, the protrusion 15 may be formed to protrude from a portion 11a of the ring portion 11 to the inner side in the axial direction, and the retainer 10 may be guided by the inner ring 2 at the protrusion 15. In this case, the contact area between the retainer 10 and the inner ring 2 can be reduced, and the friction generated between the retainer 10 and the inner ring 2 can be reduced. In the case of inner ring guidance, the protrusion 15 may be formed to protrude from a portion 11a of the ring portion 11 to the outer side in the axial direction.

[0045] Description of Reference Numerals

[0046] 1…ball bearing; 2…inner ring; 3…outer ring; 5…ball; 10…cage (crown-type cage); 11…ring; 12…column; 15…protrusion; 20…pocket; 20a…inner surface; 21…bottom.

Claims

1. A crown-shaped retainer for retaining a plurality of balls arranged in a circumferential direction so as to be able to roll freely, the crown-shaped retainer comprising: a donut-shaped ring; and A plurality of columnar portions protrude from the ring portion toward one side in the axial direction and are arranged in the circumferential direction, A pocket for arranging one of the plurality of balls is formed between adjacent column portions. The inner surface of the pocket extends along a cylinder having a central axis parallel to the radial direction. A protrusion that protrudes radially inward or outward is formed at least at a portion of the ring portion corresponding to the bottom of the pocket. 2 . The crown-shaped cage according to claim 1 , formed of a resin material. 3 . The crown-shaped retainer according to claim 1 , wherein the protrusion is formed only on a portion of the ring portion corresponding to the bottom of the pocket. 4 . The crown-type cage according to claim 1 , wherein the projection projects radially inward from the ring portion. 5 . The crown-type cage according to claim 1 , wherein the projection projects radially outward from the ring portion. 6 . A ball bearing comprising: an inner ring; an outer ring; the plurality of balls arranged between the inner ring and the outer ring; and the crown-shaped cage according to any one of claims 1 to 5 for retaining the plurality of balls so as to be able to roll freely.

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