CN107435685B

CN107435685B - Ball bearing

Info

Publication number: CN107435685B
Application number: CN201710256609.9A
Authority: CN
Inventors: 阪本康裕
Original assignee: JTEKT Corp
Current assignee: JTEKT Corp
Priority date: 2016-04-22
Filing date: 2017-04-19
Publication date: 2021-03-30
Anticipated expiration: 2037-04-19
Also published as: CN107435685A; JP2017194141A; JP6717028B2

Abstract

The ball bearing (10) includes an inner ring (11), an outer ring (12), a plurality of balls (13), and an annular retainer (14). The retainer (14) comprises: an annular portion (21), the annular portion (21) being on a first axial side; and a plurality of retainer bars (22), each of the plurality of retainer bars (22) extending from the annular portion (21) toward the second axial side, and a space between retainer bars (22) adjacent in the circumferential direction serves as a recess (20) that accommodates the ball (13). The retainer outer surface (30) is configured to be an outer peripheral surface of the annular portion (21) and a radially outer surface of the retainer rod (22), the retainer outer surface (30) having: a contact surface portion (35), the contact surface portion (35) contacting a first axial side portion of an inner peripheral surface of the outer ring (12) so as to position the retainer (14) in the radial direction; and an inclined surface portion (37), the inclined surface portion (37) being inclined radially inward from an axially intermediate portion of the holder outer surface (30) toward the second axial side.

Description

Ball bearing

Technical Field

The present invention relates to a ball bearing.

Background

Many rolling bearings are used in various types of industrial equipment. The rolling bearings each include an inner ring, an outer ring, a plurality of rolling elements each interposed between the inner ring and the outer ring, and an annular retainer that retains the plurality of rolling elements. Among these rolling bearings, a ball bearing having balls as rolling elements particularly has small rotational resistance and excellent high-speed rotation performance.

As a cage for a ball bearing, a so-called crown cage is known, which has: an annular portion on one axial side of the ball; and a plurality of retainer rods extending from the annular portion toward the other axial side. In this retainer, a space between retainer bars adjacent in the circumferential direction serves as a recess for accommodating a ball (see, for example, japanese patent application publication 2008-45572(JP2008-45572 a)).

In a ball bearing having an opportunity to rotate at high speed, the cage is positioned radially by the outer race. More specifically, when the ball bearing (inner race) rotates, the cage also rotates together with the plurality of balls. At this time, the outer peripheral surface of the annular portion provided in the retainer can be brought into sliding contact with the inner peripheral surface of the shoulder portion of the outer ring, and the retainer is thus guided by the outer ring.

Disclosure of Invention

When the ball bearing rotates at high speed, a large centrifugal force acts on the cage. In the holder, the annular portion has a circular shape as a whole, and is therefore less likely to be affected by centrifugal force. That is, the annular portion is hardly deformed. On the other hand, when a centrifugal force acts on the holder rod, in particular, there is a possibility that: the end side of the retainer rod located away from the annular portion is deformed substantially radially outwardly. When the retainer rod is significantly deformed, the tip side thereof may interfere with the outer race. Furthermore, the annular portion may be affected by the retainer rod being significantly deformed, which may result in an unintended contact pattern of the annular portion with the shoulder of the outer race. When the cage is brought into a state where the cage is not properly guided by the outer race due to the influence of centrifugal force, the rotational resistance of the ball bearing may increase, abnormal noise may be generated, and/or the rotational performance of the ball bearing may deteriorate.

In view of the above, the present invention provides a ball bearing capable of stably guiding a cage by an outer ring even when the ball bearing rotates at high speed.

A ball bearing according to an aspect of the present invention includes: an inner ring; an outer ring; a plurality of balls disposed between the inner race and the outer race; and an annular retainer that retains the plurality of balls. The holder has: an annular portion on a first axial side; and a plurality of retainer bars, each of the plurality of retainer bars extending from the annular portion toward the second axial side. The space between the retainer bars adjacent in the circumferential direction serves as a recess for accommodating the ball. The retainer outer surface is configured to include an outer peripheral surface of the annular portion and a radially outer surface of the retainer rod, the retainer outer surface having: a contact surface portion that contacts a first axial side portion of an inner peripheral surface of the outer ring so as to position the retainer in a radial direction; and an inclined surface portion inclined radially inward from an axially intermediate portion of the holder outer surface toward the second axial side.

According to this ball bearing, even when a portion of the retainer rod on the second axial side is deformed radially outward due to centrifugal force, the inclined surface portion can prevent the portion of the retainer rod from contacting the outer ring. In addition, by the inclined surface portion, the volume of the portion of the holder rod on the second axial side can be reduced, which can reduce the weight thereof. In this way, the magnitude of the centrifugal force is reduced, and the deformation thereof can be mitigated. As a result, even when the ball bearing rotates at a high speed, the contact surface portion of the outer surface of the cage can appropriately contact the first axial side portion of the inner circumferential surface of the outer ring. Therefore, the high-speed rotation performance of the ball bearing can be maintained.

The axially intermediate portion of the outer surface of the retainer may be an axially intermediate portion of the radially outer surface of the retainer rod. In this case, the inclined surface portion is configured to be inclined radially inward toward the second axial side from an axially intermediate portion of the radially outer surface of the retainer rod. With this configuration, the retainer rod is narrowed in the radial direction on the distal end side (second axial side); however, the retainer rod does not narrow on the proximal side (first axial side). Therefore, the rigidity of the retainer rod is maintained, and thereby deformation of the retainer rod caused by centrifugal force can be suppressed.

The holder inner surface configured by including the inner peripheral surface of the annular portion and the radially inner surface of the holder rod may have: a small-diameter inner surface portion including an inner peripheral surface; and a large-diameter inner surface portion located on a radially outer side of the small-diameter inner surface portion and also located on a second axial side of the small-diameter inner surface portion. With this configuration, the holder inner surface has a stepped shape formed by the small-diameter inner surface portion and the large-diameter inner surface portion. Therefore, the wall surface portion between the small diameter inner surface portion and the large diameter inner surface portion can suppress the outflow of the lubricant present on the second axial side of the inner surface of the retainer to the first axial side, and facilitate the use of the lubricant for lubricating the balls.

A boundary between the small-diameter inner surface portion and the large-diameter inner surface portion may be separated from an end of the notch in a direction toward the second axial side. The end is an end of the recess on the first axial side. In this case, the outflow of the lubricant to the first axial side is suppressed by the wall surface portion between the small-diameter inner surface portion and the large-diameter inner surface portion, the lubricant may adhere to the balls held in the recesses, and thus the use of the lubricant for lubricating the balls is further facilitated.

According to the aspect of the invention, even when the ball bearing rotates at high speed, the contact surface portion of the outer surface of the retainer can appropriately contact the first axial side portion of the inner peripheral surface of the outer ring. Therefore, the high-speed rotation performance of the ball bearing can be maintained.

Drawings

Features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, in which like reference numerals represent like elements, and wherein:

FIG. 1 is a cross-sectional view of one example of a ball bearing;

fig. 2 is an explanatory view of the holder and shows a state where the holder is cut in half; and is

Fig. 3 is an enlarged cross-sectional view of a portion and periphery of the retainer.

Detailed Description

Embodiments of the present invention will be described below based on the drawings. FIG. 1 is a cross-sectional view of one example of a ball bearing. The ball bearing 10 includes an inner race 11, an outer race 12, a plurality of balls (rolling elements) 13 each of which is disposed between the inner race 11 and the outer race 12, and an annular retainer 14 that retains the balls 13 at circumferentially spaced intervals. The ball bearing 10 shown in fig. 1 is a deep groove ball bearing. Note that, in the following description, the axial direction is a direction parallel to the center line C0 of the ball bearing 10. This centerline will be referred to as bearing centerline C0. The centerlines of the inner race 11, the outer race 12, and the cage 14 correspond to a bearing centerline C0.

The inner ring 11 is a cylindrical member, and is provided with an inner ring raceway 51 on the outer peripheral side thereof. The inner ring raceway 51 has a recessed groove shape, and the balls 13 roll thereon. Further, the inner ring 11 is provided with a first shoulder 53 on a first axial side (one side in the axial direction) of the inner ring raceway 51, and is also provided with a second shoulder 54 on a second axial side (the other side in the axial direction) of the inner ring raceway 51. In this embodiment, both

shoulders

53, 54 have the same outer diameter.

The outer ring 12 is a cylindrical member, and is provided with an outer ring raceway 52 on its inner peripheral side. The outer ring raceway 52 has a recessed groove shape, and the balls 13 roll thereon. Further, the outer ring 12 is provided with a first shoulder 55 on a first axial side of the outer ring raceway 52, and is also provided with a second shoulder 56 on a second axial side of the outer ring raceway 52. In this embodiment, the two

shoulders

55, 56 have the same inner diameter.

A plurality of balls 13 are disposed in an annular space 15 formed between the inner race 11 and the outer race 12. When the ball bearing 10 rotates (when the inner ring 11 rotates in the present embodiment), each of these balls 13 rolls on the inner ring raceway 51 and the outer ring raceway 52 in a state of being held by the cage 14.

Fig. 2 is an explanatory view of the holder 14 and shows a state in which the holder 14 is cut in half. The cage 14 can hold the plurality of balls 13 at a prescribed interval (equal interval) in the circumferential direction. For this reason, the retainer 14 is formed with a plurality of recesses 20 in the circumferential direction, each of the plurality of recesses 20 holding the ball 13. The cage 14 of the present embodiment is a so-called crown cage, and has: an annular portion 21, the annular portion 21 being provided on a first axial side (left side in fig. 1 and 2) of the balls 13; and a plurality of retainer bars 22, the plurality of retainer bars 22 being provided so as to extend from the annular portion 21 toward the second axial side (the right side in fig. 1 and 2). The annular portion 21 is a portion shown in cross section (hatching) in the upper half portion of fig. 2, and a boundary between the annular portion 21 and the retainer bar 22 is shown in two-dot chain line. The space between the adjacent retainer bars 22 in the circumferential direction and on the second axial side of the annular portion 21 serves as a recess 20 that accommodates the ball 13. The retainer 14 is made of resin, and is molded by injection molding, for example, in such a manner that the ring portion 21 and the retainer rod 22 are integrated.

The recess 20 of the holder 14 has a recess surface 25 along the shape of an imaginary cylindrical surface. The imaginary cylindrical surface is a surface of a cylindrical shape having an imaginary line orthogonal to the bearing center line C0 as a center line. The diameter of the recess surface 25 (imaginary cylindrical surface) is slightly larger than the diameter of the ball 13. Since the ball 13 is a ball, the ball 13 makes point contact with the recess surface 25 in a shape along a cylindrical surface. A claw portion 29 is formed on the second axial side of each retainer bar 22, and the claw portion 29 prevents the balls 13 from falling out of the recesses 20.

The outer peripheral surface 31 of the annular portion 21 is a cylindrical surface centered on the bearing center line C0. In addition, the radially outer surface 32 of each retainer rod 22 is a surface extending from the outer peripheral surface 31 of the annular portion 21 toward the second axial side. Note that, although described below, the radially outer surface 32 of the retainer rod 22 has an inclined surface portion 37, and the inclined surface portion 37 is inclined from the axially intermediate portion 36 of the radially outer surface 32. The outer peripheral surface 31 of the annular portion 21 and the radially outer surfaces 32 of the plurality of retainer bars 22 constitute a retainer outer surface 30.

The inner peripheral surface 41 of the annular portion 21 is a cylindrical surface centered on the bearing center line C0. In addition, the radially inner surface 42 of each retainer rod 22 is a surface that extends from the inner peripheral surface 41 of the annular portion 21 toward the second axial side. Note that, although described below, the radially inner surface 42 of the retainer rod 22 is a stepped surface. The inner peripheral surface 41 of the annular portion 21 and the radially inner surfaces 42 of the plurality of retainer bars 22 constitute a retainer inner surface 40.

Fig. 3 is an enlarged cross-sectional view of a portion and periphery of the retainer 14. First, the holder outer surface 30 will be described. The outer peripheral surface 31 of the annular portion 21 opposes the inner peripheral surface 19 of the shoulder portion 55 of the outer race 12, defining a gap between the outer peripheral surface 31 and the inner peripheral surface 19. When the retainer 14 is deviated in the radial direction, the outer peripheral surface 31 of the annular portion 21 (and the first axial side portion 38a of the retainer rod 22, which will be described below) can contact the inner peripheral surface 19 of the shoulder portion 55. Thus, the retainer 14 acts as an outer race guide retainer that is radially positioned by the outer race 12.

The radially outer surface 32 of each retainer rod 22 has an outer intermediate surface portion 38 and an inclined surface portion 37. The outer intermediate surface portion 38 is a surface along an imaginary cylindrical surface centered on the bearing center line C0 (see fig. 2), and the imaginary cylindrical surface and the outer peripheral surface 31 of the annular portion 21 have the same diameter (outer diameter). In other words, the outer peripheral surface 31 of the annular portion 21 and the outer intermediate surface portion 38 of the retainer rod 22 are smoothly continuous in the axial direction, and therefore, a bending angle is not defined between the outer peripheral surface 31 of the annular portion 21 and the outer intermediate surface portion 38 of the retainer rod 22. The inclined surface portion 37 has a bending angle P with respect to the outer intermediate surface portion 38. The angle P is an inclination angle with respect to an imaginary cylindrical surface centered on the bearing center line C0.

The outer peripheral surface 31 of the annular portion 21 and the first axial side portion 38a of the outer intermediate surface portion 38 continuing from the outer peripheral surface 31 can contact the inner peripheral surface 19 of the shoulder portion 55 of the outer ring 12, and these outer peripheral surface 31 and the first axial side portion 38a serve as the contact surface portion 35 that can contact the outer ring 12. When the contact surface portion 35 contacts the outer race 12, the retainer 14 is positioned radially.

The inclined surface portion 37 is formed from an end portion of the outer intermediate surface portion 38 on the second axial side (the axial intermediate portion 36 of the holder outer surface 30) toward the second axial side. The inclined surface portion 37 is inclined radially inward (toward the inner ring 11 side) as advancing toward the second axial side. In the present embodiment, the inclined surface portion 37 is linearly inclined. An end 37a of the inclined surface portion 37 on the second axial side is the farthest end of the holder rod 22 on the second axial side. As described so far, the holder outer surface 30 in this embodiment is configured by sequentially having the outer peripheral surface 31, the outer intermediate surface portion 38, and the inclined surface portion 37 of the annular portion 21 from the first axial side.

Next, the holder inner surface 40 will be described. The radially inner surface 42 of each retainer rod 22 has an inner intermediate surface portion 48 and a large diameter inner surface portion 47. The inner intermediate surface portion 48 is a surface along an imaginary cylindrical surface centered on the bearing center line C0 (see fig. 2), and the imaginary cylindrical surface has the same diameter (inner diameter) as the inner peripheral surface 41 of the annular portion 21. In other words, the inner peripheral surface 41 of the annular portion 21 and the inner intermediate surface portion 48 of the retainer rod 22 are smoothly continuous in the axial direction, and thus no bending angle is defined between the inner peripheral surface 41 of the annular portion 21 and the inner intermediate surface portion 48 of the retainer rod 22. The inner peripheral surface 41 and the inner intermediate surface portion 48 of the annular portion 21 constitute a small-diameter inner surface portion 46 located on a common imaginary cylindrical surface.

The large-diameter inner surface portion 47 is a surface along an imaginary cylindrical surface centered on the bearing center line C0 (see fig. 2), and the large-diameter inner surface portion 47 is located on the radially outer side of the small-diameter inner surface portion 46 (inner intermediate surface portion 48). For this reason, a wall surface portion 49 is provided between the small-diameter inner surface portion 46 (inner intermediate surface portion 48) and the large-diameter inner surface portion 47. The wall surface portion 49 in the present embodiment is an annular surface facing the second axial side, and is orthogonal to the small-diameter inner surface portion 46 (inner intermediate surface portion 48) and the large-diameter inner surface portion 47.

The wall surface portion 49 is a surface serving as a boundary between the small diameter inner surface portion 46 and the large diameter inner surface portion 47. In the present embodiment, as described above, the radially inner surface 42 of each retainer rod 22 includes an inner intermediate surface portion 48. Thus, the wall surface portion 49 is separated from the end portion 26 of the notch 20 in the direction toward the second axial side. The end 26 is the end of the recess 20 on the first axial side. Note that the wall surface portion 49 is located on the first axial side of the center of the ball 13, and is biased to the side close to the annular portion 21. The holder inner surface 40 in this embodiment is constructed by sequentially having the inner peripheral surface 41, the inner intermediate surface portion 48, the wall surface portion 49 and the large-diameter inner surface portion 47 of the annular portion 21 from the first axial side, as has been described so far. Wherein the inner peripheral surface 41 and the inner intermediate surface portion 48 of the annular portion 21 constitute a small-diameter inner surface portion 46.

As has been described so far, in the retainer 14 provided in the ball bearing 10 in the present embodiment, the retainer outer surface 30 is configured to include the outer peripheral surface 31 of the annular portion 21 and the radially outer surfaces 32 of the plurality of retainer bars 22. The holder outer surface 30 has a contact surface portion 35 and an inclined surface portion 37. The contact surface portion 35 serves as a surface that contacts a first axial side portion of the inner peripheral surface of the outer ring 12, i.e., the inner peripheral surface 19 of the shoulder portion 55, to position the retainer 14 in the radial direction. The inclined surface portion 37 is a surface that is inclined radially inward as proceeding toward the second axial side from the axially intermediate portion 36 of the holder outer surface 30. In the present embodiment, the axially intermediate portion 36 is an axially intermediate portion of the radially outer surface 32 of the retainer rod 22.

Here, when the ball bearing 10 rotates (the inner race 11 rotates), the cage 14 rotates together with the plurality of balls 13. When the ball bearing 10 rotates at a high speed, the rotational speed of the cage 14 also increases. Then, a centrifugal force acts on the holder 14, and the holder 14 is elastically deformed in the diameter expansion direction. To address this problem, the holder outer surface 30 has the contact surface portion 35 and the inclined surface portion 37, as described above. The contact surface portion 35 guides the holder 14 rotating at high speed. Thus, even when the holder bar 22 (particularly the portion 27 on the second axial side thereof) is deformed radially outward (toward the outer ring 12 side) due to centrifugal force, the inclined surface portion 37 can prevent the portion 27 on the second axial side of the holder bar 22 from coming into contact with the outer ring 12.

The portion 27 on the second axial side of the retainer rod 22 is deformed radially outward when centrifugal force acts on the portion 27. The inclined surface portion 37 can have a shape along a cylindrical surface centered on the bearing center line C0 (see fig. 2) by being deformed by rotating at a predetermined high rotational speed of the portion 27. Note that the inclination angle (angle P, see fig. 3) of the inclined surface portion 37 is set in consideration of this point. In other words, the inclination angle is set such that when the retainer 14 is rotated at the maximum rotational speed in terms of design performance and thus the retainer rod 22 is deformed due to centrifugal force, the state in which the inclined surface portion 37 becomes parallel to the bearing center line C0 is the upper limit of the deformation.

In addition, the portion 27 of the holder rod 22 on the second axial side has such a shape that a portion thereof is chipped (lack) due to the inclined surface portion 37. Thus, the volume of the portion 27 is reduced, which enables further reduction in its weight. In this way, the magnitude of the centrifugal force generated thereon is reduced, and the deformation thereof can be mitigated. From what has been described so far, even when the ball bearing 10 is rotating at high speed, the portion 27 of the retainer rod 22 on the second axial side is not in contact with the outer ring 12, and the contact surface portion 35 can appropriately contact the inner peripheral surface 19 of the shoulder portion 55 on the first axial side of the outer ring 12. As a result, an increase in the rotational resistance of the retainer 14 is prevented, generation of abnormal noise or heat is prevented, and thus high-speed rotation performance can be maintained.

Further, in the present embodiment, as described above, the inclined surface portions 37 are configured to be inclined radially inward as proceeding from the axial intermediate portion 36 in the radially outer surface 32 of the holder rod 22 toward the second axial side. For this reason, the distal end side (the portion 27 on the second axial side) of the holder rod 22 is narrowed in the radial direction; however, the holder rod 22 does not narrow on the proximal side (the portion 28 on the first axial side). Therefore, the rigidity of the holder rod 22 is maintained, and thus deformation of the holder rod 22 caused by centrifugal force can be suppressed.

When attention is paid to the retainer inner surface 40, the retainer inner surface 40 is configured to include an inner peripheral surface 41 of the annular portion 21 and a radially inner surface 42 of the retainer rod 22. The holder inner surface 40 has: a small diameter inner surface portion 46, the small diameter inner surface portion 46 including the inner peripheral surface 41 of the annular portion 21; and a large-diameter inner surface portion 47, the large-diameter inner surface portion 47 being located radially outward of the small-diameter inner surface portion 46 and on a second axial side of the small-diameter inner surface portion 46. In this way, the holder inner surface 40 has a stepped shape formed by the small-diameter inner surface portion 46 and the large-diameter inner surface portion 47. Here, grease (lubricant) is provided in the annular space 15 of the ball bearing 10 so as to ensure lubricity of each part. When the ball bearing 10 rotates, for example, there are the following cases: the grease on the inner ring 11 side moves radially outward due to centrifugal force, adheres to the holder inner surface 40, and stays on the holder inner surface 40. However, in the holder inner surface 40 of the present embodiment, the wall surface portion 49 between the small diameter inner surface portion 46 and the large diameter inner surface portion 47 can suppress the grease G (refer to fig. 3) present in the second axial side of the holder inner surface 40 from flowing out to the first axial side. Therefore, the grease G can easily enter the space between the recess surface 25 and the ball 13, and lubrication of the ball 13 using the grease G is facilitated.

Specifically, in the embodiment shown in fig. 3, the boundary between the small-diameter inner surface portion 46 and the large-diameter inner surface portion 47, i.e., the wall surface portion 49, is separated from the end portion 26 of the notch 20 in the direction toward the second axial side. The end 26 is the end of the recess 20 on the first axial side. Therefore, the outflow of the grease G to the first axial side is suppressed by the wall surface portion 49, the grease G further easily enters the space between the pocket surface 25 and the ball 13, and easily adheres to the ball 13 held in the pocket 20. Thus, its use for lubrication of the balls 13 is further facilitated.

Further, as shown in fig. 2, each holder lever 22 has a pair of

claw portions

29, 29 on the second axial side. The space between these

claws

29, 29 is a substantially V-shaped cut. In this way, the weight of the holder rod 22 is reduced, which further reduces the centrifugal force acting thereon accompanying the rotation of the holder 14. Further, since each of the retainer bars 22 includes a substantially V-shaped cutout, the claw portions 29 can be easily elastically deformed when the retainer 14 is attached to the plurality of balls 13 interposed between the inner race 11 and the outer race 12 during assembly of the ball bearing 10. Thus, the assembly thereof is facilitated.

Note that, in the present embodiment, the case where the axially intermediate portion 36 of the holder outer surface 30, which is the starting point of the inclined surface portion 37 in the holder outer surface 30, is the axially intermediate portion in the radially outer surface 32 of the holder rod 22, that is, the case where the radially outer surface 32 of the holder rod 22 has the outer intermediate surface portion 38 other than the inclined surface portion 37, has been described. However, (although not shown), the outer intermediate surface portion 38 may not be provided. In this case, the inclined surface portion 37 is a surface having a starting point on a boundary between the annular portion 21 and each holder rod 22 and inclined radially inward as advancing toward the second axial side. In other words, the entire radially outer surface 32 of the retainer rod 22 serves as the inclined surface portion 37.

In addition, the case where the wall surface portion 49 in the holder inner surface 40 is orthogonal to the small-diameter inner surface portion 46 (inner intermediate surface portion 48) and the large-diameter inner surface portion 47 has been described. However, the wall surface portion 49 may be inclined with respect to these inner peripheral surface 41 and inner intermediate surface portion 48. Further, the case where the large-diameter inner surface portion 47 has a shape along a cylindrical surface centered on the bearing center line C0 has been described. However, the large-diameter inner surface portion 47 may be a surface that is inclined radially inward as advancing toward the second axial side. In this case, even in the case where centrifugal force acts on the retainer 14 and the retainer bar 22 (the portion 27 on the second axial side) is deformed radially outward, the grease G adhering to the large-diameter inner surface portion 47 is less likely to flow out toward the second axial side. Thus, its use for lubrication of the balls 13 is facilitated.

The embodiments that have been disclosed thus far are illustrative in all respects and therefore not restrictive. That is, the ball bearing of the present invention is not limited to the illustrated mode, and may be another mode within the scope of the present invention. The ball bearings may be bearings other than deep groove ball bearings, but may be angular contact ball bearings.

Claims

1. A ball bearing comprising:

an inner ring (11);

an outer ring (12);

a plurality of balls (13), the plurality of balls (13) being disposed between the inner race and the outer race; and

an annular retainer (14), the annular retainer (14) retaining the plurality of balls, wherein

The holder has: an annular portion (21), the annular portion (21) being on a first axial side; and a plurality of retainer bars (22), each of the plurality of retainer bars (22) extending from the annular portion toward a second axial side, and a space between the retainer bars adjacent in the circumferential direction serves as a recess (20), the balls being accommodated in the recesses (20),

on an inner peripheral side of the outer ring (12), the outer ring (12) is provided with an outer ring raceway (52), the outer ring raceway (52) has a recessed groove shape, and the plurality of balls (13) roll on the outer ring raceway (52), and on the first axial side of the outer ring raceway (52), the outer ring (12) is provided with a first shoulder (55), and on the second axial side of the outer ring raceway (52), the outer ring (12) is provided with a second shoulder (56),

the retainer outer surface (30) configured by including an outer peripheral surface (31) of the annular portion and a radially outer surface (32) of the retainer rod has: a contact surface portion (35), the contact surface portion (35) contacting a first axial side portion of an inner peripheral surface of the outer ring so as to position the retainer in a radial direction; and an inclined surface portion (37), the inclined surface portion (37) being inclined radially inward toward the second axial side from an axial intermediate portion (36) of the retainer outer surface, the axial intermediate portion (36) being located on the first axial side of a center of each of the plurality of balls (13) and on the second axial side of a boundary between the outer ring raceway (52) and the first shoulder portion (55),

each of the plurality of retainer bars (22) has a pair of claw portions (29) on the second axial side to prevent the balls (13) from falling off from the notches (20), and a radially outer surface of each claw portion (29) of the pair of claw portions (29) is included in the inclined surface portion (37), and

an end portion (37a) of the inclined surface portion (37) on the second axial side is located on the first axial side of a boundary between the outer ring raceway (52) and the second shoulder portion (56).

2. The ball bearing of claim 1, wherein

The axially intermediate portion (36) of the retainer outer surface (30) is an axially intermediate portion of the radially outer surface of the retainer rod.

3. A ball bearing according to claim 1 or 2, wherein

The retainer inner surface (40) configured by including an inner peripheral surface (41) of the annular portion and a radially inner surface (42) of the retainer rod has: a small-diameter inner surface portion (46), the small-diameter inner surface portion (46) including an inner peripheral surface; and a large-diameter inner surface portion (47), the large-diameter inner surface portion (47) being located on a radially outer side of the small-diameter inner surface portion, and the large-diameter inner surface portion (47) also being located on the second axial side of the small-diameter inner surface portion.

4. The ball bearing of claim 3, wherein

A boundary between the small diameter inner surface portion (46) and the large diameter inner surface portion (47) is separated from an end portion (26) of the notch in a direction toward the second axial side, the end portion (26) being an end portion of the notch on the first axial side.