Rolling bearing and cage for rolling bearing

Abstract

This rolling bearing comprises: an inner ring (11) that has, on the outer periphery, an inner ring raceway (21) and a shoulder (25) adjacent to one side of the inner ring raceway (21) in the axial direction; an outer ring (12) that has an outer ring raceway (22) on the inner periphery; a plurality of rolling elements (13) provided between the inner ring raceway (21) and the outer ring raceway (22); and an annular cage (14) that holds the plurality of rolling elements (13) spaced circumferentially. The cage (14) has: an annular body (31) that is located further toward the one side in the axial direction than the rolling elements (13); a plurality of prongs (32) that extend to the other side in the axial direction from the annular body (31); and a restricting portion (33) that is located further toward the inside in the radial direction than the prongs (32), extends to the other side in the axial direction from the annular body (31), and restricts the displacement of the cage (14) by contact with the inner ring raceway (21). An inner peripheral surface (61a) of the restricting portion (33) and an inner peripheral surface (31c) of the annular body (31) are arranged to face the shoulder (25). The inner peripheral surface (61a) of the restricting portion (33) and / or the inner peripheral surface (31c) of the annular body (31) is formed with a protrusion (55) that can make contact with the shoulder (25).

Description

Rolling bearings and cages for rolling bearings

[0001] The present disclosure relates to a rolling bearing and a cage for a rolling bearing.

[0002] Patent Document 1 discloses a rolling bearing including an inner ring, an outer ring, multiple rolling elements disposed between the inner ring and the outer ring, and an annular cage. This rolling bearing is a ball bearing that uses a resin cage known as a crown cage. The crown cage has an annular body located on one axial side of the rolling elements and multiple "horns" protruding from the annular body on the other axial side. Pockets are formed between adjacent horns in the circumferential direction, and the rolling elements are disposed in these pockets.

[0003] The cage described in Patent Document 1 further includes a guide portion (regulating portion). The guide portion protrudes from the annular body toward the other axial side, radially inward of the horns. A protrusion protruding radially inward is provided at the tip of the guide portion. The protrusion has the function of restricting radial and axial displacement of the cage by contacting the inner ring raceway.

[0004] Japanese Patent Application Laid-Open No. 2021-76186

[0005] When a rolling bearing rotates at high speed, centrifugal force can cause the lubricant to fly toward the outer ring, resulting in a lack of lubricant between the inner circumferential surface of the cage and the outer circumferential surface of the inner ring, which can lead to wear of the cage.

[0006] An object of the present disclosure is to appropriately lubricate the space between the cage and the inner ring and suppress wear of the cage.

[0007] The rolling bearing of the present disclosure comprises an inner ring having an inner ring raceway and a shoulder on its outer periphery adjacent to one axial side of the inner ring raceway; an outer ring having an outer ring raceway on its inner periphery; a plurality of rolling elements arranged between the inner ring raceway and the outer ring raceway; and an annular retainer that holds the plurality of rolling elements at intervals in the circumferential direction, wherein the retainer has an annular body located on one axial side of the rolling elements, a plurality of horns extending from the annular body to the other axial side, and a regulating portion extending from the annular body radially inward of the horns to the other axial side and contacting the inner ring raceway to limit displacement of the retainer, wherein the inner surfaces of the regulating portion and the inner surfaces of the annular body are positioned opposite the shoulder, and a convex portion that can contact the shoulder is formed on at least one of the inner surfaces of the regulating portion and the inner surfaces of the annular body.

[0008] The present disclosure provides a retainer for a rolling bearing, comprising: an annular body located on one axial side of rolling elements included in the rolling bearing; a plurality of horns extending from the annular body on the other axial side; and a regulating portion extending from the annular body on the other axial side radially inward of the horns and contacting an inner ring raceway of an inner ring included in the rolling bearing to limit displacement of the retainer, wherein the inner surfaces of the regulating portion and the inner surfaces of the annular body are positioned opposite a shoulder of the inner ring, and a convex portion capable of contacting the shoulder is formed on at least one of the inner surfaces of the regulating portion and the annular body.

[0009] According to the present disclosure, grease can be present in the gap formed when the convex portion comes into contact with the shoulder of the inner ring, between the inner surface of the regulating portion or the inner surface of the annular body and the shoulder of the inner ring, thereby providing appropriate lubrication between the convex portion and the shoulder of the inner ring and suppressing wear of the convex portion.

[0010] FIG. 1 is a cross-sectional view of a rolling bearing according to a first embodiment. FIG. 2 is a perspective view of a cage. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 4. FIG. 4 is an enlarged view of a portion of the cage as viewed from the other axial side. FIG. 3 is a cross-sectional view taken along line V-V in FIG. 4. FIG. 4 is an enlarged view of a portion of the cage as viewed from the radially inner side. FIG. 5 is an enlarged cross-sectional view of a restriction portion main body of the cage. FIG. 5 is an enlarged view of a portion of the cage according to a second embodiment as viewed from the radially inner side. FIG. 6 is an enlarged view of a portion of the cage according to a third embodiment as viewed from the radially inner side.

[0011] <Outline of Embodiments of the Present Disclosure> Below, an outline of embodiments of the present disclosure will be listed and described.

[0012] (1) In one embodiment, the rolling bearing comprises an inner ring having an inner ring raceway and a shoulder on its outer periphery adjacent to one axial side of the inner ring raceway; an outer ring having an outer ring raceway on its inner periphery; a plurality of rolling elements arranged between the inner ring raceway and the outer ring raceway; and an annular cage that holds the plurality of rolling elements at intervals in the circumferential direction, wherein the cage has an annular body located on one axial side of the rolling elements, a plurality of horns extending from the annular body to the other axial side, and a regulating portion that extends from the annular body radially inward of the horns to the other axial side and contacts the inner ring raceway to limit displacement of the cage, wherein the inner peripheral surface of the regulating portion and the inner peripheral surface of the annular body are positioned opposite the shoulder, and a protrusion that can contact the shoulder is formed on at least one of the inner peripheral surface of the regulating portion and the inner peripheral surface of the annular body.

[0013] In the rolling bearing configured as described above, a convex portion is formed on at least one of the inner circumferential surface of the restricting portion of the cage and the inner circumferential surface of the annular body, so that when the convex portion contacts the shoulder of the inner ring, a gap is formed between the inner circumferential surface and the shoulder, allowing lubricant to reside in this gap. In particular, lubricant that is thrown radially outward as the rolling bearing rotates and then returns radially inward within the bearing can flow into this gap. Therefore, the lubricant present around the convex portion can adequately lubricate the area between the convex portion and the shoulder of the inner ring, suppressing wear of the convex portion.

[0014] (2) Preferably, the portion of the protrusion that contacts the shoulder is formed in a spherical shape. With this configuration, the contact area between the protrusion and the shoulder can be reduced, thereby reducing the frictional resistance therebetween.

[0015] (3) Preferably, the regulating portion has a regulating portion main body extending from the annular body to the other axial side, and a protruding portion protruding radially inward from a tip end of the regulating portion main body and contacting the inner ring raceway, the protruding portion being disposed at a position spaced apart from the protruding portion to the one axial side. With this configuration, a lubricant can be present between the protruding portion and the protruding portion in the axial direction, thereby more appropriately lubricating the area between the protruding portion and the shoulder.

[0016] (4) Preferably, the angle between the shoulder and an imaginary line connecting the convex portion and the edge on one axial side of the inner circumferential surface of the annular body is greater than the maximum assumed inclination angle of the cage. Here, "the maximum assumed inclination angle of the cage" refers to the maximum assumed inclination angle when the horns and the restricting portion open radially outward due to high-speed rotation of the rolling bearing and the annular body is deformed so as to incline toward one axial side. With this configuration, even if the cage is deformed due to high-speed rotation of the rolling bearing, the edge on one axial side of the inner circumferential surface of the annular body is less likely to come into contact with the shoulder, thereby suppressing wear of the edge.

[0017] (5) In an embodiment, the retainer is a retainer for a rolling bearing, and includes an annular body located on one axial side of the rolling elements of the rolling bearing, a plurality of horns extending from the annular body on the other axial side, and a regulating portion extending from the annular body on the other axial side radially inward of the horns and contacting an inner ring raceway of an inner ring of the rolling bearing to limit displacement of the retainer, wherein the inner surfaces of the regulating portion and the annular body are positioned opposite a shoulder of the inner ring, and a convex portion capable of contacting the shoulder is formed on at least one of the inner surfaces of the regulating portion and the annular body.

[0018] According to the cage for a rolling bearing having the above configuration, a convex portion is formed on at least one of the inner circumferential surface of the restricting portion of the cage and the inner circumferential surface of the annular body. When the convex portion contacts a shoulder of the inner ring, a gap is formed between the inner circumferential surface and the shoulder, allowing lubricant to reside in this gap. In particular, lubricant that is thrown radially outward as the rolling bearing rotates and then returns radially inward within the bearing can flow into this gap. Therefore, the lubricant present around the convex portion can adequately lubricate the area between the convex portion and the shoulder of the inner ring, thereby suppressing wear of the convex portion.

[0019] <Details of Embodiments of the Present Disclosure> Hereinafter, details of embodiments of the present disclosure will be described with reference to the drawings. [First Embodiment] Fig. 1 is a cross-sectional view of a rolling bearing according to a first embodiment. Specifically, Fig. 1 shows a cross-section including a center line C (also referred to as a "bearing center line C") of a rolling bearing 10. The rolling bearing 10 shown in Fig. 1 includes an inner ring 11, an outer ring 12, a plurality of rolling elements 13 provided between the inner ring 11 and the outer ring 12, and an annular cage 14. The rolling elements 13 of the present disclosure are balls, and the rolling bearing 10 is a ball bearing (deep groove ball bearing). The rolling bearing 10 of the present disclosure uses grease as a lubricant. The grease is filled into a bearing interior 16 of the rolling bearing 10.

[0020] In the present disclosure, the direction along the center line C of the rolling bearing 10 is the axial direction of the rolling bearing 10, and is simply referred to as the "axial direction." This axial direction also includes a direction parallel to the center line C. The right side in FIG. 1 is defined as one axial direction, and the left side in FIG. 1 is defined as the other axial direction. The direction perpendicular to the bearing center line C is the radial direction of the rolling bearing 10, and is simply referred to as the "radial direction." The direction in which the rolling bearing 10 (inner ring 11 in the present disclosure) rotates around the bearing center line C is the circumferential direction of the rolling bearing 10, and is simply referred to as the "circumferential direction."

[0021] The rolling bearing 10 is provided with seals 15 on both axial sides. The seals 15 prevent grease from leaking out (outside the bearing) from an annular space 16 (inside the bearing) between the inner ring 11 and the outer ring 12. The seals 15 also function to prevent foreign matter from outside the bearing from entering the inside 16 of the bearing.

[0022] The inner ring 11 is an annular member. An inner ring raceway 21, a shoulder 25, and a recessed groove 23 are formed on the outer periphery of the inner ring 11. The inner ring raceway 21 is the part with which the rolling elements 13 roll and come into contact. The inner ring raceway 21 is formed by a groove having a recessed arc shape with a radius slightly larger than the radius of the rolling elements 13.

[0023] The shoulders 25 are provided adjacent to both axial sides of the inner ring raceway 21. The shoulders 25 are cylindrical surfaces centered on the bearing center line C. The grooves 23 are formed at both axial ends of the inner peripheral surface of the inner ring 11. The inner surface of the groove 23 and the inner peripheral portion of the seal 15 face each other with a gap between them. This gap forms a labyrinth seal. The seal 15 may be a contact-type seal that comes into contact with the inner surface of the groove 23.

[0024] The outer ring 12 is an annular member. An outer ring raceway 22, a shoulder 26, and a seal groove 24 are formed on the inner circumference of the outer ring 12. The outer ring raceway 22 is the part with which the rolling elements 13 roll and come into contact. The outer ring raceway 22 is formed by a groove having a concave arc shape with a radius slightly larger than the radius of the rolling elements 13.

[0025] The shoulders 26 are provided adjacent to both axial sides of the outer ring raceway 22. The shoulders 26 are formed on a cylindrical surface centered on the bearing center line C. The seal grooves 24 are formed on both axial ends of the inner peripheral surface of the outer ring 12. The outer peripheral portion of the seal 15 is attached to the seal grooves 24.

[0026] The plurality of rolling elements 13 are arranged in a line in the circumferential direction between the inner ring raceway 21 and the outer ring raceway 22. When the rolling bearing 10 (inner ring 11) rotates, the rolling elements 13 roll on the inner ring raceway 21 and the outer ring raceway 22.

[0027] Fig. 2 is a perspective view of the cage. Fig. 3 is a cross-sectional view taken along line III-III in Fig. 4. Fig. 4 is an enlarged view of a portion of the cage as viewed from the other axial side. The cage 14 has an annular body (annular portion) 31, a plurality of horns (pillar portions) 32, and a restricting portion 33. The annular body 31 is a circular ring-shaped portion and is located on one axial side of the rolling elements 13. An inner peripheral surface 31c of the annular body 31 faces the shoulder 25 of the inner ring 11. The inner peripheral surface 31c of the annular body 31 is a cylindrical surface centered on the center line C.

[0028] The horns 32 extend from a radially outer portion 31a (see FIG. 3) of the annular body 31 toward the other axial side. All of the multiple horns 32 have the same shape. On the other axial side of the annular body 31, between a pair of horns 32 adjacent in the circumferential direction, a pocket 30 that accommodates the rolling elements 13 is formed. A plurality of pockets 30 are formed along the circumferential direction.

[0029] The restricting portion 33 is provided radially inward of the horn 32. The restricting portion 33 extends from the radially inner portion 31b of the annular body 31 to the other axial direction. A radial gap 17 is provided between the horn 32 and the restricting portion 33. This gap 17 forms a groove connecting two circumferentially adjacent pockets 30, 30.

[0030] The cage 14 can hold multiple rolling elements 13 at circumferential intervals. The portion of the horns 32 having a surface 28 facing the circumferential direction becomes part of the pocket 30. The surface 28 is parallel to an imaginary plane including the center line C and the center of the pocket 30. The opposing surfaces 28 are the same distance to this imaginary plane. The rolling elements 13 can come into contact with this surface 28. The portion of the annular body 31 having a surface 29 facing the other axial side becomes another part of the pocket 30. This surface 29 is a plane perpendicular to the bearing center line C. The rolling elements 13 can come into contact with this surface 29. The cage 14 is made of a resin (synthetic resin) such as polyamide, and is manufactured by injection molding. The annular body 31, the horns 32, and the restricting portion 33 are integrally molded, and the cage 14 consists of a single member.

[0031] The regulating portion 33 has a regulating portion main body 61 and a protrusion 35. The regulating portion main body 61 is connected to the annular body 31 and extends from the annular body 31 toward the other axial side. The inner circumferential surface 61a of the regulating portion main body 61 faces the shoulder 25 of the inner ring 11. The inner circumferential surface 61a of the regulating portion main body 61 is a cylindrical surface centered on the center line C. The inner circumferential surface 61a of the regulating portion main body 61 is flush with the inner circumferential surface 31c of the annular body 31. The protrusion 35 is provided at the end of the regulating portion main body 61 on the other axial side. The protrusion 35 protrudes radially inward (toward the inner ring 11) from the regulating portion main body 61. A portion of the protrusion 35 is capable of contacting the inner ring raceway 21.

[0032] When the center line of the cage 14 is aligned with the bearing center line C (as shown in FIG. 3 ), a gap is formed between the protrusion 35 and the inner ring raceway 21. When the cage 14 is displaced radially from this state, the protrusion 35 comes into contact with the inner ring raceway 21 from the radially outer side. This limits the radial displacement of the cage 14. When the cage 14 is displaced axially to one side from the state shown in FIG. 3 , the protrusion 35 comes into contact with the inner ring raceway 21 from the other axial side. This limits the displacement of the cage 14 to one axial side. Note that when the cage 14 is displaced axially to the other side from the state shown in FIG. 3 , the surface 29 of the annular body 31 facing the rolling elements 13 comes into contact with the rolling elements 13. This limits the displacement of the cage 14 to the other axial side.

[0033] 2, the distance Q between the tips of a pair of circumferentially adjacent horns 32-1, 32-2 on the other axial side, across one pocket 30 containing the rolling element 13, is larger than the diameter of the rolling element 13. Therefore, when the cage 14 attempts to displace in one axial direction, the displacement of the cage 14 is not restricted by the rolling element 13. However, the cage 14 is provided with a restricting portion 33, and the protruding portion 35 of the restricting portion 33 can contact the inner ring raceway 21 from the other axial direction (see FIG. 1), so the cage 14 does not fall off from between the inner ring 11 and the outer ring 12.

[0034] In this way, the restricting portion 33 has the function of restricting radial and axial displacement of the cage 14. In other words, the restricting portion 33 positions the cage 14 by contacting the inner ring raceway 21. The restricting portion 33 makes contact (sliding contact) with the inner ring raceway 21 to guide the rotation of the cage 14. The rotation of the cage 14 is not only guided by the restricting portion 33, but is also guided by the contact of the protrusions 55 formed on the inner circumferential surface 31c of the annular body 31 with the shoulder 25 of the inner ring 11. Details of the protrusions 55 will be described later. Hereinafter, the inner circumferential surface 31c of the annular body 31 and the inner circumferential surface 61a of the restricting portion main body 61 may be referred to as the inner circumferential surfaces 31c, 61a of the cage 14.

[0035] Figure 5 is a cross-sectional view taken along line VV in Figure 4. As shown in Figures 4 and 5, a cutout 37 is formed in the horn 32. The cutout 37 is provided from one side to the other in the axial direction of the horn 32, and is open to the other axial side and radially outward.

[0036] As shown in Figure 4, the groove 17 connects a pair of circumferentially adjacent pockets 30, 30. The groove 17 is a recessed groove in which grease (lubricant) can reside. The groove 17 is a space surrounded in the radial direction by the horn 32 and the restricting portion 33. The groove 17 is open on the other axial side and closed on one axial side by the annular body 31. A restricting portion main body 61 of the restricting portion 33 forms a wall on the radially inner side of the groove 17.

[0037] 6 is an enlarged view of a portion of the cage as viewed from the radially inner side. As shown in FIGS. 5 and 6 , a protrusion 55 is formed on the inner circumferential surface of the cage 14, specifically, on the inner circumferential surface 61a of the restricting portion main body 61. One protrusion 55 is formed approximately at the center of the restricting portion 33 in the circumferential direction. The protrusion 55 is disposed at a distance on one axial side of the protruding portion 35. The protrusion 55 is disposed on the inner circumferential surface 61a of the restricting portion 33 at a position adjacent to the inner circumferential surface 31c of the annular body 31. The protrusion 55 may be formed across both the inner circumferential surface 61a of the restricting portion main body 61 and the inner circumferential surface 31c of the annular body 31, or may be formed only on the inner circumferential surface 31c of the annular body 31.

[0038] The protrusions 55 are formed in a spherical shape. Therefore, as shown in FIG. 6 , the protrusions 55 are formed in a circular shape when viewed from the radially inner side, and as shown in FIG. 5 , the protrusions 55 are formed in an arc-shaped cross section. The height (radial length) of the protrusions 55 is smaller than the radial gap between the inner circumferential surfaces 61 a, 31 c of the retainer 14 and the shoulder 25 when the center line of the retainer 14 is aligned with the bearing center line C. The center line of the retainer 14 is radially offset from the bearing center line C, causing the protrusions 55 to contact the shoulder 25 of the inner ring 11, and the rotation of the retainer 14 is guided by the inner ring 11. The contact of the protrusions 55 with the shoulder 25 reduces the contact area of ​​the retainer 14 with the shoulder 25, thereby reducing the frictional resistance between the shoulder 25 and the retainer 14.

[0039] Because the convex portions 55 are formed on the inner circumferential surfaces 61 a, 31 c of the cage 14, gaps are always formed between the inner circumferential surfaces 61 a, 31 c of the cage 14 and the shoulder 25. Grease can be present in these gaps. Therefore, the grease in these gaps can be used to appropriately lubricate the gap between the cage 14 and the shoulder 25, particularly between the convex portions 55 and the shoulder 25. This reduces wear on the convex portions 55 and improves the life of the cage 14. Furthermore, because only one convex portion 55 is formed and a wide gap is formed between the inner circumferential surfaces 61 a, 31 c of the cage 14 and the shoulder 25, more grease can be present.

[0040] As shown in Figure 1, the grease filled inside the bearing 16 of the rolling bearing 10 is thrown radially outward by the centrifugal force caused by the rotation of the inner ring 11, but then passes between the cage 14 and the seal 15 and is returned radially inward, as shown by the dotted arrow a. The grease returned in this way enters the gap between the shoulder 25 and the inner circumferential surfaces 31c, 61a of the cage 14, as shown by the arrow b in Figure 5. The grease that has entered in this way can also be used to provide appropriate lubrication between the protrusion 55 and the shoulder 25.

[0041] FIG. 7 is an enlarged cross-sectional view of the restricting portion main body of the cage. In FIG. 7 , an imaginary line L (a tangent to the protrusion 55) connects an edge P2 on one axial side of the inner peripheral surface 31c of the annular body 31 of the cage 14 to a point P1 on the protrusion 55, and the angle θ between this imaginary line L and the shoulder 25 of the inner ring 11 is indicated. When the rolling bearing 10 rotates at high speed, the horns 32 and the restricting portion 33 of the cage 14 open radially outward as indicated by arrow c due to centrifugal force, and the cage 14 is deformed so that the annular body 31 tilts toward one axial side as indicated by arrow d. The angle θ is set to be larger than the maximum angle (maximum assumed tilt angle) at which the annular body 31 is expected to tilt. This prevents the edge P2 of the annular body 31 from contacting the shoulder 25 of the inner ring 11, even if the annular body 31 tilts during high-speed rotation of the rolling bearing 10, and maintains a state in which the protrusion 55 can contact the shoulder 25. This suppresses wear on the edge P2 of the annular body 31, and maintains a gap between the inner circumferential surfaces 61a, 31c of the retainer 14 and the shoulder 25, allowing the grease flowing in the direction of arrow a in Figure 1 to enter the gap.

[0042] Second Embodiment Fig. 8 is an enlarged view of a portion of a cage according to a second embodiment, viewed from the radially inner side. In this embodiment, a plurality of protrusions 55 are formed on the inner peripheral surfaces 61a, 31c of the cage 14. Specifically, three protrusions 55 are arranged side by side in the circumferential direction. The plurality of protrusions 55 may be arranged side by side in the axial direction, or may be arranged side by side in both the circumferential and axial directions. Two or four or more protrusions 55 may be provided.

[0043] In this embodiment, the number of protrusions 55 that come into contact with the shoulder 25 of the inner ring 11 is greater than in the first embodiment, and therefore it is possible to reduce the pressure applied to each protrusion 55 by contact with the shoulder 25. The other configurations and effects are the same as those of the first embodiment.

[0044] [Third Embodiment] Fig. 9 is an enlarged view of a portion of a cage according to a third embodiment, viewed from the radially inner side. Fig. 10 is an enlarged cross-sectional view of a restricting portion main body of the cage. In this embodiment, the shape of the convex portion 55 formed on the inner circumferential surface 61a, 31c of the cage 14 differs from that of the first embodiment. Specifically, the convex portion 55 of this embodiment has an extension portion 55a that extends toward the other axial side and connects to the protrusion 35. The outer surface of the end portion on one axial side of the convex portion 55 is formed spherically. In this embodiment, as in the first embodiment, when the convex portion 55 contacts the shoulder 25, a gap capable of retaining grease can be formed between the inner circumferential surface 61a, 31c of the cage 14 and the shoulder 25.

[0045] In this embodiment, for example, when molding a retainer using a mold that is divided in the axial direction, it is possible to eliminate the snagging that occurs when the mold part that forms the convex portion 55 is separated (de-molded) from the convex portion 55, making it easy to manufacture the retainer 14.

[0046] The embodiments disclosed herein are illustrative in all respects and are not restrictive. The scope of the present invention is not limited to the above-described embodiments, and includes all modifications within the scope of equivalents to the configurations described in the claims. For example, the shape of the convex portion may be an oval or elliptical shape, or a polygonal shape such as a square or triangle, when viewed from the radially inner side. However, in any case, it is preferable that the outer surface of the convex portion has no corners and is curved in a spherical shape (a circular arc in cross section).

[0047] 10: Rolling bearing 11: Inner ring 12: Outer ring 13: Rolling element 14: Cage 21: Inner ring raceway 22: Outer ring raceway 25: Shoulder 31: Annular body 31c: Inner peripheral surface 32: Horn 33: Restricting portion 35: Protrusion 55: Protrusion 61: Restricting portion main body 61a: Inner peripheral surface

Claims

1. an inner ring having an inner raceway and a shoulder on an outer periphery adjacent to one axial side of the inner raceway; an outer ring having an outer ring raceway on an inner circumference; A plurality of rolling elements provided between the inner ring raceway and the outer ring raceway; and an annular cage that holds the rolling elements at intervals in a circumferential direction, The cage includes an annular body located on one axial side of the rolling elements, A plurality of protrusions extending from the annular body to the other axial direction; a restricting portion extending from the annular body toward the other axial direction at a position radially inward of the prongs and contacting the inner ring raceway to restrict displacement of the cage, an inner circumferential surface of the restricting portion and an inner circumferential surface of the annular body are disposed opposite the shoulder, a protrusion capable of coming into contact with the shoulder is formed on at least one of an inner circumferential surface of the restricting portion and an inner circumferential surface of the annular body, an end portion on the other axial side of the protruding portion is disposed at a position not reaching the inner ring raceway, A rolling bearing, wherein the cage has a plurality of protrusions formed in a circumferential direction.

2. 2. The rolling bearing according to claim 1, wherein a portion of said protrusion that comes into contact with said shoulder is formed into a spherical shape.

3. The restricting portion has a restricting portion main body extending from the annular body to the other axial direction side; a protruding portion protruding radially inward from a tip end portion of the regulating portion main body and contacting the inner ring raceway, 3. The rolling bearing according to claim 1, wherein the convex portion is disposed at a position spaced apart from the protruding portion on one side in the axial direction.

4. A rolling bearing as described in any one of claims 1 to 3, wherein an angle between the shoulder and an imaginary line connecting the convex portion and an axially one end edge of the inner peripheral surface of the annular body is greater than an assumed maximum inclination angle of the retainer.

5. A cage for a rolling bearing, comprising: an annular body located on one axial side of a rolling element of the rolling bearing; A plurality of protrusions extending from the annular body to the other axial direction; a restricting portion extending from the annular body toward the other axial direction at a position radially inward of the tines and contacting an inner ring raceway of an inner ring of the rolling bearing to restrict displacement of the cage, an inner circumferential surface of the restricting portion and an inner circumferential surface of the annular body are disposed opposite a shoulder of the inner ring, a protrusion capable of coming into contact with the shoulder is formed on at least one of an inner circumferential surface of the restricting portion and an inner circumferential surface of the annular body, an end portion on the other axial side of the protruding portion is disposed at a position not reaching the inner ring raceway, The cage has a plurality of protrusions formed in a circumferential direction.

6. The rolling bearing according to any one of claims 1 to 4, wherein a gap is formed between an inner peripheral surface of the regulating portion on the other axial side of the protrusion and an outer peripheral surface of the shoulder.