Sliding member and rolling bearing
Patent Information
- Application Number
- JP2025502088
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2025-08-19
- Publication Date
- 2025-11-04
- Estimated Expiration
- 2043-04-27
Abstract
Description
Sliding member and rolling bearing
[0001] The present disclosure relates to a sliding member and a rolling bearing.
[0002] A rolling bearing with an anti-electrolytic corrosion function is disclosed in Patent Document 1. The rolling bearing described in Patent Document 1 is a bearing that supports a rotating shaft of an electric motor mounted on an electric vehicle or the like. This rolling bearing includes an outer ring, an inner ring, a plurality of balls arranged between the outer and inner rings, and an annular seal (sliding member) that closes an end opening of the bearing internal space between the outer and inner rings. The seal includes an elastic material such as conductive rubber. The inner and outer peripheral edges of this elastic material are in contact with the inner and outer rings, respectively. The contact of the elastic material with the inner and outer rings electrically connects the inner ring to the outer ring through the elastic material, thereby preventing current from flowing between the inner ring and the balls and between the outer ring and the balls, and suppressing electrolytic corrosion of the inner ring raceway, the outer ring raceway, and the balls.
[0003] JP 2015-102200 A
[0004] The elastic material of the seal (sliding member) in Patent Document 1 has a certain degree of conductivity due to the incorporation of carbon fiber into the rubber. However, in order to further suppress electrolytic corrosion of the raceway, it is desired to further increase the conductivity of the seal. Therefore, an object of the present disclosure is to increase the conductivity of the sliding member.
[0005] (1) A sliding member according to the present disclosure comprises a sheet, rubber, and a metal ring, wherein the sheet is formed of conductive fibers, is fixed in contact with a first member made of steel, and is in slidable contact with a second member made of steel, the rubber comprising at least a first rubber portion fixed to a surface of a first axial side of the metal ring, and a second rubber portion fixed to a surface of a second axial side of the metal ring, the sheet comprising a sheet portion fixed to the second rubber portion, the first surface on the first axial side being the surface of the first axial side of the metal ring or the surface of the first axial side of the first rubber portion, the second surface on the second axial side being the surface of the second rubber portion and / or the sheet portion, the first surface and the second surface being arranged at positions overlapping each other in the radial direction and the circumferential direction, and a first thickness being a thickness from the surface of the first axial side of the metal ring to the first surface, The second thickness is a thickness from a surface on a second side in the axial direction of the metal ring to the second surface, and the second thickness is greater than the first thickness.
[0006] (2) The rolling bearing of the present disclosure comprises an inner ring having an inner ring raceway, an outer ring having an outer ring raceway arranged radially outward of the inner ring raceway, a plurality of rolling elements arranged to be able to roll between the inner ring raceway and the outer ring raceway, and the sliding member described in (1) above arranged radially between an axial end of the inner ring and an axial end of the outer ring, wherein one of the inner ring and the outer ring is the first member, and the other of the inner ring and the outer ring is the second member.
[0007] The sliding member of the present disclosure includes a sheet that is a nonwoven or woven fabric formed of conductive fibers, and this sheet can have lower electrical resistance and higher conductivity than an elastic material made of rubber with carbon fibers kneaded in. Therefore, the sliding member electrically connects the first member and the second member via the sheet, and current can flow from one of the first member and the second member to the other via the sheet.
[0008] FIG. 1 is a cross-sectional view showing an example of a rolling bearing according to a first embodiment of the present disclosure. FIG. 2 is an enlarged cross-sectional view of a sliding member. FIG. 3 is an enlarged cross-sectional view of a radially outer portion of the sliding member of FIG. 2. FIG. 4 is an enlarged cross-sectional view of a radially inner portion of the sliding member of FIG. 2. FIG. 5A is a view of a circumferential portion of the sliding member as viewed from the axial direction, from the bearing external space side. FIG. 5B is a cross-sectional view taken along line A-A in FIG. 5A. FIG. 5C is a cross-sectional view taken along line B-B in FIG. 5A. FIG. 6 is a cross-sectional view showing a molding die for the sliding member. FIG. 7 is an enlarged cross-sectional view of a portion of the molding die for the sliding member. FIG. 8 is an enlarged cross-sectional view of a portion of the molding die in an open state. FIG. 9 is an enlarged cross-sectional view of a sliding member according to a second embodiment.
[0009] <Outline of Embodiments of the Invention of the Present Disclosure> Below, outlines of embodiments of the invention of the present disclosure will be listed and described.
[0010] (1) A sliding member according to the present disclosure comprises a sheet, rubber, and a metal ring, wherein the sheet is formed of conductive fibers, is fixed in contact with a first member made of steel, and is in slidable contact with a second member made of steel, the rubber comprising at least a first rubber portion fixed to a surface of a first axial side of the metal ring, and a second rubber portion fixed to a surface of a second axial side of the metal ring, the sheet comprising a sheet portion fixed to the second rubber portion, the first surface on the first axial side being the surface of the first axial side of the metal ring or the surface of the first axial side of the first rubber portion, the second surface on the second axial side being the surface of the second rubber portion and / or the sheet portion, the first surface and the second surface being arranged at positions overlapping each other in the radial direction and the circumferential direction, and a first thickness being a thickness from the surface of the first axial side of the metal ring to the first surface, The second thickness is a thickness from a surface on a second side in the axial direction of the metal ring to the second surface, and the second thickness is greater than the first thickness.
[0011] According to this configuration, the sliding member includes a sheet that is a nonwoven or woven fabric made of conductive fibers, and the sheet has lower electrical resistance and higher conductivity than an elastic material made of rubber with carbon fibers kneaded in. Therefore, the sliding member electrically connects the first member and the second member via the sheet, and current can flow from one of the first member and the second member to the other via the sheet.
[0012] The second thickness of the sliding member is greater than the first thickness. A mold for molding a sliding member having such a configuration has a structure for pressing the metal ring in the axial direction, and it is possible to suppress displacement of the metal ring relative to the mold.
[0013] (2) Preferably, the metal ring of the sliding member of (1) above is disposed on a first axial side of the sheet with a gap therebetween, and the rubber has a portion disposed in the gap.
[0014] According to this configuration, the metal ring and the sheet do not come into direct contact with each other, and the sheet is prevented from being damaged by being subjected to a load from the metal ring.
[0015] (3) Preferably, the rubber of the sliding member of (1) or (2) above is bonded to the entire first side in the axial direction of the sheet.
[0016] With this configuration, the shape of the entire sheet can be maintained by the rubber.
[0017] (4) A rolling bearing according to the present disclosure comprises: an inner ring having an inner ring raceway; an outer ring having an outer ring raceway arranged radially outward of the inner ring raceway; a plurality of rolling elements arranged to be able to roll between the inner ring raceway and the outer ring raceway; and a sliding member according to any one of (1) to (3) above arranged radially between an axial end of the inner ring and an axial end of the outer ring, wherein one of the inner ring and the outer ring is the first member, and the other of the inner ring and the outer ring is the second member.
[0018] With this configuration, the outer ring and inner ring of the rolling bearing can be electrically connected by a sheet of sliding material, and electric current can be passed from one of the outer ring and inner ring to the other via this sheet, thereby suppressing electrolytic corrosion of the outer ring raceway, inner ring raceway, and balls.
[0019] <Details of the embodiment of the invention of the present disclosure> An embodiment of the invention of the present disclosure will be described below. Fig. 1 is a cross-sectional view showing an example of a rolling bearing of the present disclosure. The rolling bearing 10 shown in Fig. 1 supports a rotating shaft S of a motor mounted on, for example, an electric vehicle or a hybrid vehicle. In Fig. 1, the rotating shaft S is indicated by a virtual line (two-dot chain line).
[0020] The rolling bearing 10 includes an outer ring 11, an inner ring 12, a plurality of rolling elements 13, a cage 14, and a sliding member 15. In this embodiment, the rolling elements 13 are balls. The rolling bearing 10 is a deep groove ball bearing. The outer ring 11 is attached to a housing H of a motor. The inner ring 12 is fitted onto and fixed to the outer peripheral surface of a rotating shaft S. In FIG. 1 , the housing H is indicated by a virtual line (two-dot chain line). In this embodiment, the outer ring 11 is a fixed ring, and the inner ring 12 is a rotating ring. The outer ring 11 and the inner ring 12 are formed of a steel material such as bearing steel. High-carbon chromium bearing steel (e.g., SUJ2 or SUJ3 as specified in the JIS standard) can be used as the bearing steel. However, the outer ring 11 and the inner ring 12 may also be formed of other steel materials such as carburized bearing steel, carbon steel, chromium steel, or stainless steel.
[0021] The outer ring 11 and the inner ring 12 are arranged concentrically. In this embodiment, the central axis of the outer ring 11 and the central axis of the inner ring 12 coincide with the central axis C of the rolling bearing 10. Furthermore, in this embodiment, the direction along the central axis C and the direction parallel to the central axis C are defined as the "axial direction." Similarly, the direction perpendicular to the central axis C is defined as the "radial direction." Similarly, the direction along a circle centered on the central axis C is defined as the "circumferential direction." Furthermore, in this embodiment, the left side of FIG. 1 is defined as the axial first side, the right side of FIG. 1 is defined as the axial second side, the upper side of FIG. 1 is defined as the radial first side, and the lower side of FIG. 1 is defined as the radial second side. Furthermore, in this embodiment, the radial first side is the radial outer side, and the radial second side is the radial inner side. Therefore, in the following description, the radial first side may be referred to as the radial outer side, and the radial second side may be referred to as the radial inner side.
[0022] The outer ring 11 includes an outer ring raceway 21, two shoulders 22, and two annular grooves 23. The outer ring raceway 21 is provided on the inner peripheral surface of the outer ring 11. The balls 13 roll on this outer ring raceway 21. Two shoulders 22 are provided on both axial sides of the outer ring raceway 21. Two annular grooves 23 are provided between the shoulders 22 and the side surfaces of the outer ring 11, respectively. The annular grooves 23 have a circumferentially continuous annular groove shape. The sliding members 15 are attached to the annular grooves 23 located on both axial sides of the outer ring 11. However, the sliding members 15 may be attached to only the annular grooves 23 located on one of the first and second axial sides of the outer ring 11. In this case, the annular grooves 23 to which the sliding members 15 are not attached may be omitted.
[0023] The inner ring 12 has an inner ring raceway 31, two shoulders 32, and two sliding member contact surfaces 33. The inner ring raceway 31 is provided on the outer peripheral surface of the inner ring 12. The balls 13 roll on this inner ring raceway 31. Two shoulders 32 are provided on both axial sides of the inner ring raceway 31. Two sliding member contact surfaces 33 are provided between the shoulders 32 and the side surfaces of the inner ring 12. The sliding member contact surface 33 is provided annularly around the entire circumference of the inner ring 12. The sliding member contact surface 33 is groove-shaped in a cross section including the central axis C of the inner ring 12. The radially inner end of the sliding member 15 contacts the sliding member contact surface 33.
[0024] The balls 13 are disposed between the outer ring 11 and the inner ring 12. The balls 13 are in rolling contact with the outer ring raceway 21 and the inner ring raceway 31. The plurality of balls 13 are held at intervals in the circumferential direction by an annular cage 14.
[0025] The cage 14 has an annular body 16 and a plurality of horns (pillars) 17. The annular body 16 is provided on a second axial side of the balls 13. The plurality of horns (pillars) 17 are provided extending from the annular body 16 to a first axial side. A pocket 18 is a space between two circumferentially adjacent horns 17 on the first axial side of the annular body 16. The balls 13 are accommodated in the pocket 18. The pocket 18 is open on the first axial side.
[0026] The sliding member 15 is annular. The sliding member 15 is attached and fixed to the outer ring (first member) 11 and is in sliding contact with the inner ring (second member) 12. Specifically, the sliding member 15 is fixed to the outer ring 11 by having its radially outer end (end on the first radial side) fitted into an annular groove 23 of the outer ring 11. The radially inner end (end on the second radial side) of the sliding member 15 contacts a sliding member contact surface 33 of the inner ring 12. The sliding members 15 are disposed on both axial sides of the rolling bearing 10. Therefore, the bearing internal space K1, which is an annular space between the outer ring 11 and the inner ring 12 and in which the balls 13 are present, is closed on both axial sides by the sliding members 15. The sliding members 15 separate the bearing internal space K1 in which the balls 13 are present from a bearing external space K2, which is a space on the first and second axial sides of the rolling bearing 10.
[0027] The sliding member 15 includes a conductive sheet 43 disposed between a radially outer end and a radially inner end. The sheet 43 is exposed on the surface of the sliding member 15 at the radially outer end and is in contact with the annular groove 23 of the outer ring 11. The sheet 43 is exposed on the surface of the sliding member 15 at the radially inner end and is in contact with the sliding member contact surface 33 of the inner ring 12. Therefore, the sliding member 15 forms a current path for preventing current generated by a motor or the like from flowing between the outer ring 11 and the inner ring 12 via the rolling elements 13.
[0028] An oil film made of lubricating oil or grease is formed between the balls 13 and the inner ring raceway 31, and between the balls 13 and the outer ring raceway 21. The oil film has insulating properties. The insulating properties of the oil film result in the balls 13 being insulated from the inner ring raceway 31 and from the outer ring raceway 21. When an oil film is formed between the balls 13 and the inner ring raceway 31 and a potential difference of a predetermined value or less occurs between the balls 13 and the inner ring raceway 31, no current flows between the inner ring raceway 31 and the balls 13. When an oil film is formed between the balls 13 and the outer ring raceway 21 and a potential difference of a predetermined value or less occurs between the balls 13 and the outer ring raceway 21, no current flows between the balls 13 and the outer ring raceway 21. However, when the oil film between the balls 13 and the inner ring raceway 31 is partially broken down, or when a potential difference exceeding a predetermined value occurs between the balls 13 and the inner ring raceway 31, a current flows between the balls 13 and the inner ring raceway 31, and the current may cause electrolytic corrosion in the balls 13 and / or the inner ring raceway 31. When the oil film between the balls 13 and the outer ring raceway 21 is partially broken down, or when a potential difference exceeding a predetermined value occurs between the balls 13 and the outer ring raceway 21, a current may flow between the balls 13 and the outer ring raceway 21, and the current may cause electrolytic corrosion in the balls 13 and / or the outer ring raceway 21.
[0029] The rolling bearing 10 of this embodiment is provided with a sliding member 15 that forms a current path, so that before the potential difference between the balls 13 and the inner ring raceway 31 or the potential difference between the balls 13 and the outer ring raceway 21 increases, the potential difference between the outer ring 11 and the inner ring 12 is reduced by passing a current between the outer ring 11 and the inner ring 12 via the sliding member 15. By reducing the potential difference between the outer ring 11 and the inner ring 12, the occurrence of electrolytic corrosion in the balls 13, the inner ring raceway 31, and the outer ring raceway 21 is suppressed.
[0030] [Specific Structure of Slide Member 15] Figure 2 is an enlarged cross-sectional view of the slide member. Figure 3 is an enlarged cross-sectional view of a radially outer portion of the slide member of Figure 2. Figure 4 is an enlarged cross-sectional view of a radially inner portion of the slide member of Figure 2. In the following description, a specific structure of the slide member 15 arranged on the first axial side (left side in Figure 1) of the rolling bearing 10 will be described. Therefore, in the description of this slide member 15, the first axial side can be rephrased as the bearing external space K2 side, and the second axial side can be rephrased as the bearing internal space K1 side. The slide member 15 arranged on the second axial side (right side in Figure 1) of the rolling bearing 10 is the same part as the slide member 15 arranged on the first side, but is arranged inverted in the axial direction.
[0031] 2 to 4, the sliding member 15 has a metal ring 41, a rubber 42, and a sheet 43. The metal ring 41, the rubber 42, and the sheet 43 are all annular. The metal ring 41 and the rubber 42, and the rubber 42 and the sheet 43 are bonded to each other, and are integrated as a whole.
[0032] The metal ring 41 is made of a metal such as a galvanized steel plate or stainless steel. The metal ring 41 is formed by processing a plate material. The metal ring 41 includes an annular portion 41a and a cylindrical portion 41b. The annular portion 41a is arranged perpendicular to the axial direction. The cylindrical portion 41b is arranged parallel to the axial direction. The cylindrical portion 41b is arranged at the radial outer end of the annular portion 41a. The cylindrical portion 41b extends from the radial outer end of the annular portion 41a to the second axial side (the side of the bearing internal space K1). The annular portion 41a and the cylindrical portion 41b of the metal ring 41 are formed by plastic processing the plate material into a substantially L-shaped cross section.
[0033] The rubber 42 is electrically conductive. Specifically, the rubber 42 is manufactured by blending, for example, synthetic rubber with an electrically conductive material. The electrically conductive material is carbon black, metal powder, or the like. The specific structure of the rubber 42 will be described later together with the structure of the sheet 43.
[0034] The sheet 43 is made of a nonwoven or woven fabric made of conductive fibers. In this embodiment, carbon fibers are used as the conductive fibers used in the sheet 43. However, other materials, such as fibers made of conductive metals such as copper and nickel, may also be used as the conductive fibers. The electrical resistance of the sheet 43 is lower than the electrical resistance of the rubber 42. Therefore, the sheet 43 has higher electrical conductivity than the rubber 42.
[0035] In this embodiment, the sheet 43 further contains a synthetic resin as a binder. The binder is fixed to the surface of a portion of the conductive fibers contained in the sheet 43. The sheet 43 in this embodiment is a nonwoven fabric or a woven fabric made of conductive fibers to which the binder is fixed.
[0036] The seat 43 integrally includes an intermediate portion 44, a fixed portion 45, and a sliding portion 46. The fixed portion 45 is a portion located radially outward (on a first radial side) from the metal ring 41. The sliding portion 46 is a portion located radially inward (on a second radial side) from the metal ring 41. The intermediate portion 44 is a portion located between the fixed portion 45 and the sliding portion 46.
[0037] The intermediate portion 44 of the seat 43 has a first portion (first seat portion) 44a1, a second portion (second seat portion) 44a2, a third portion 44b, and a fourth portion 44c. The first portion 44a1 and the second portion 44a2 extend in the radial direction. As shown in FIGS. 3 and 4 , the first portion 44a1 and the second portion 44a2 are disposed at intervals t11 and t12 on the second axial side (the bearing internal space K1 side) of the annular portion 41a of the metal ring 41.
[0038] The second portions 44a2 are disposed on both radial sides of the first portion 44a1. In other words, the first portion 44a1 is located midway along the radial direction of the second portion 44a2. The first portion 44a1 and the second portion 44a2 are connected in the radial direction. The first portion 44a1 is located on the first axial side (closer to the bearing external space K2) than the second portion 44a2. Therefore, the distance t11 between the first portion 44a1 and the metal ring 41 is smaller than the distance t12 between the second portion 44a2 and the metal ring 41. A step portion 44a3 is located at the boundary between the first portion 44a1 and the second portion 44a2.
[0039] 2 and 3, the third portion 44b of the seat 43 is bent from the radially outer end of the second portion 44a2 toward the second axial side and extends substantially in the axial direction. Therefore, the third portion 44b has a substantially cylindrical shape. As shown in FIG. 3, the third portion 44b is disposed radially inward of the cylindrical portion 41b of the metal ring 41 with a distance t2 therebetween.
[0040] The fourth portion 44c is bent radially outward from the end of the third portion 44b on the second axial side and extends radially. As shown in Fig. 3, the fourth portion 44c is disposed on the second axial side of the cylindrical portion 41b of the metal ring 41 with a distance t3 therebetween. Therefore, the intermediate portion 44 of the seat 43 and the metal ring 41 are disposed with distances t11, t12, t2, and t3 therebetween throughout the entire radial direction.
[0041] The fixing portion 45 of the seat 43 is continuous with the fourth portion 44c of the intermediate portion 44. As shown in FIG. 3, the fixing portion 45 has a fifth portion 45a and a sixth portion 45b. The fifth portion 45a extends radially continuously from the radially outer end of the fourth portion 44c of the intermediate portion 44. The sixth portion 45b extends from the radially outer end of the fifth portion 45a while inclining toward the first axial side and radially outward. The tip of the sixth portion 45b constitutes the radially outer end of the seat 43. The tip of the sixth portion 45b is in direct contact with the annular groove 23 of the outer ring 11. In this embodiment, the fifth portion 45a of the fixing portion 45 is also in direct contact with the annular groove 23.
[0042] As shown in FIGS. 2 and 4 , the sliding portion 46 of the seat 43 is continuous with the second portion 44a2, which is the intermediate portion 44. In this embodiment, the portion of the seat 43 that is positioned radially inward from the radially inner end of the metal ring 41 is the sliding portion 46. The sliding portion 46 extends linearly radially inward from the second portion 44a2 of the intermediate portion 44. Therefore, the second portion 44a2 of the intermediate portion 44 and the sliding portion 46 as a whole form a ring shape perpendicular to the axial direction. The radially inner end 46a of the sliding portion 46 directly contacts the sliding member contact surface 33 of the inner ring 12. The radially inner end 46a of the sliding portion 46 is bent toward the first axial side by contacting the sliding member contact surface 33.
[0043] 2, the rubber 42 is bonded to the sheet 43 and the metal ring 41. The rubber 42 is provided over the entire first axial side (the bearing external space K2 side) of the sheet 43. The rubber 42 has a first portion 42a1, a second portion 42a2, a third portion 42a3, a fourth portion 42a4, a fifth portion 42b, a sixth portion 42c, a seventh portion 42d, an eighth portion 42e, a ninth portion 42f, a tenth portion 42b2, and an eleventh portion 42b3.
[0044] The first to fourth portions 42a1, 42a2, 42a3, and 42a4 of the rubber 42 are disposed at intervals t11, t12, t2, and t3 between the metal ring 41 and the sheet 43. The first to fourth portions 42a1, 42a2, 42a3, and 42a4 of the rubber 42 maintain the intervals t11, t12, t2, and t3 between the metal ring 41 and the sheet 43 so that the metal ring 41 and the sheet 43 are not directly bonded to each other.
[0045] The first portion 42a1 of the rubber 42 is a portion of the rubber 42 to which the first portion 44a1 of the sheet 43 is adhered. The second portion 42a2 is a portion of the rubber 42 to which the second portion 44a2 of the sheet 43 is adhered. Therefore, the second portions 42a2 are disposed on both radial sides of the first portion 42a1.
[0046] The surface of the first axial side (the bearing external space K2 side) of the first portion 42a1 and the surface of the first axial side of the second portion 42a2 are arranged on the same plane, and both are bonded to the surface of the second axial side (the bearing internal space K1 side) of the annular portion 41a of the metal ring 41. The surface of the second axial side of the first portion 42a1 is arranged closer to the first axial side than the surface of the second axial side of the second portion 42a2.
[0047] The first portion 42a1 of the rubber 42 and the first portion 44a1 of the sheet 43 are continuous in the circumferential direction around the entire circumference of the sliding member 15. However, they may be provided at multiple locations spaced apart in the circumferential direction.
[0048] The third portion 42a3 of the rubber 42 is bonded to the inner circumferential surface of the cylindrical portion 41b of the metal ring 41. The fourth portion 42a4 of the rubber 42 is bonded to the end face of the cylindrical portion 41b on the second axial side. The fifth portion 42b of the rubber 42 is continuous with the fourth portion 42a4 on the radially outer side. The fifth portion 42b is disposed in an area surrounded by the fixing portion 45 of the sheet 43 and the cylindrical portion 41b of the metal ring 41. The fifth portion 42b of the rubber 42 elastically supports the sixth portion 45b of the sheet 43 from the radially inner side. The cylindrical portion 41b of the metal ring 41 supports the fifth portion 42b of the rubber 42 from the radially inner side. Therefore, the fixed portion (radially outer end portion) 45 of the sheet 43 is pressed against the annular groove 23 of the outer ring 11 by the elasticity of the fifth portion 42b of the rubber 42 supported by the cylindrical portion 41b of the metal ring 41, and is securely brought into contact with the annular groove 23.
[0049] FIG. 5A is a view of a circumferential portion of the sliding member as viewed from the axial direction from the bearing external space side. FIG. 5B is a cross-sectional view taken along line A-A in FIG. 5A. FIG. 5C is a cross-sectional view taken along line B-B in FIG. 5A. The fifth portion 42b of the rubber 42 has recesses 42b1 on the surface on the first axial side. The recesses 42b1 are provided at multiple locations spaced apart in the circumferential direction. As shown in FIG. 5B, at the circumferential positions where the recesses 42b1 are provided, a portion of the outer circumferential surface of the cylindrical portion 41b of the metal ring 41 is covered with a thin film-like eleventh portion 42b3. As shown in FIG. 5C, between circumferentially adjacent recesses 42b1, a portion of the outer circumferential surface of the cylindrical portion 41b of the metal ring 41 is covered with a tenth portion 42b2 that is thicker than the eleventh portion 42b3. The recesses 42b1 are provided at multiple locations spaced apart in the circumferential direction, but may also be provided continuously around the entire circumference of the sliding member 15. In this case, the eleventh portion 42 b 3 is provided around the entire circumference of the sliding member 15 .
[0050] As shown in Fig. 4, the sixth portion 42c of the rubber 42 extends radially inward from the radially inner end of the second portion 42a2 of the rubber 42. The sixth portion 42c is provided with a substantially constant thickness along the side surface of the sliding portion 46 of the sheet 43 on the first axial side. The sixth portion 42c has an annular shape perpendicular to the axial direction. When the radially inner end 46a of the sliding portion 46 of the sheet 43 contacts the sliding member contact surface 33 and bends, the sixth portion 42c of the rubber 42 elastically deforms and bends together with the sliding portion 46 toward the first axial side.
[0051] 3, the seventh portion 42d of the rubber 42 bulges out from the tenth portion 42b2 and the eleventh portion 42b3 of the rubber 42 toward the first axial side, covers the surface of the first radial side and the first axial side of the annular portion 41a of the metal ring 41, and is bonded to the surface. The seventh portion 42d is continuous in the circumferential direction around the entire circumference of the sliding member 15. However, the seventh portion 42d may be provided at multiple locations spaced apart in the circumferential direction.
[0052] As shown in Fig. 4, the eighth portion 42e of the rubber 42 is disposed on the side surface of the metal ring 41 on the first axial side, extending from the radially outer end of the sixth portion 42c past the radially inner end of the metal ring 41. Therefore, the eighth portion 42e has a generally L-shaped cross section, covers the radially inner end surface of the annular portion 41a and the side surface on the first axial side, and is bonded to these surfaces. The eighth portion 42e is continuous in the circumferential direction around the entire circumference of the sliding member 15. However, the eighth portion 42e may be provided at multiple locations spaced apart in the circumferential direction.
[0053] The seventh portion 42d and the eighth portion 42e of the rubber 42 serve to firmly bond the rubber 42 and the metal ring 41 together, and prevent the rubber 42 from falling off the metal ring 41.
[0054] 3 and 4, the ninth portion (first rubber portion) 42f of the rubber 42 is a thin film-like portion that covers the surface of the first axial side of the annular portion 41a of the metal ring 41. The ninth portion 42f is disposed radially between the seventh portion 42d and the eighth portion 42e. The radially outer end of the ninth portion 42f is integral with the seventh portion 42d. The radially inner end of the ninth portion 42f is integral with the eighth portion 42e.
[0055] The axial thickness ta of the ninth portion 42f is smaller than the axial thicknesses of the seventh portion 42d and the eighth portion 42e. Therefore, as shown in FIG. 2 , the sliding member 15 has a shape in which a portion of the side surface on the first axial side is recessed. In this embodiment, the ninth portion 42f is not necessarily required and may be omitted. In this case, the side surface on the first axial side of the metal ring 41 is exposed to the outside (bearing external space K2) between the seventh portion 42d and the eighth portion 42e in the radial direction.
[0056] 3 and 4 , the sliding member 15 includes a "surface S1," a "surface S2," and a "surface S3" defined as follows: Surface S1: The surface on the first axial side of the ninth portion (first rubber portion) 42f of the rubber 42, or the surface on the first axial side of the metal ring 41 (when the ninth portion 42f is not present). Surface S2: The surface on the second axial side of the first portion (second rubber portion) 42a1 of the rubber 42 and / or the first portion (first sheet portion) 44a1 of the sheet 43. Surface S3: The surface on the second axial side of the second portion (third rubber portion) 42a2 of the rubber 42 and / or the second portion (second sheet portion) 44a2 of the sheet 43.
[0057] Here, the surfaces S1 and S2 of the sliding member 15 are arranged at positions overlapping each other in the radial and circumferential directions. As will be described later, the sheet 43 has gaps between the conductive fibers, and the rubber 42 enters the gaps in the sheet 43. Therefore, the surface S2 may be formed solely by the surface on the second axial side of the first portion 44a1 of the sheet 43, or may be formed in addition to this surface by the surface on the second axial side of the first portion 42a1 of the rubber 42 that has entered the gaps in the first portion 44a1 of the sheet 43. Alternatively, the surface S2 may be formed solely by the surface on the second axial side of the first portion 42a1 of the rubber 42 that has entered the gaps in the first portion 44a1 of the sheet 43 and passed beyond the first portion 44a1.
[0058] Similarly, surface S3 may be constituted solely by the surface on the second axial side of second portion 44a2 of sheet 43, or may be constituted in addition to this surface by the surface on the second axial side of second portion 42a2 of rubber 42 that has entered the second portion 44a2. Alternatively, surface S3 may be constituted solely by the surface on the second axial side of second portion 42a2 of rubber 42 that has entered the void in second portion 44a2 of sheet 43 and exceeded the second portion 44a2.
[0059] 3 and 4, the sliding member 15 includes a "thickness ta," a "thickness tb," and a "thickness tc" defined as follows: Thickness ta: thickness from the surface of the first side in the axial direction of the metal ring 41 to surface S1. Thickness tb: thickness from the surface of the second side in the axial direction of the metal ring 41 to surface S2. Thickness tc: thickness from the surface of the second side in the axial direction of the metal ring 41 to surface S3.
[0060] When the ninth portion (first rubber portion) 42f of the rubber 42 is present, the thickness ta is substantially the thickness of the ninth portion 42f. When the ninth portion 42f is not present, the thickness ta is substantially 0. The thickness ta is smaller than the thickness tb. Furthermore, the thickness ta and the thickness tb are smaller than the thickness tc.
[0061] 3 , the sliding member 15 includes a "surface S4," a "surface S5," and a "surface S6" defined as follows: Surface S4: A surface on a first radial side of the eleventh portion 42b3 of the rubber 42, or a surface on a first radial side of the cylindrical portion 41b of the metal ring 41 (when the eleventh portion 42b3 is not present). Surface S5: A surface on a second radial side of the third portion 42a3 of the rubber 42 and / or the third portion 44b of the sheet 43. Surface S6: A surface on a first radial side of the tenth portion 42b2 of the rubber 42.
[0062] 3, the sliding member 15 includes a "thickness td," a "thickness te," and a "thickness tf" defined as follows: Thickness td: thickness from the outer peripheral surface of the cylindrical portion 41b of the metal ring 41 to the surface S4. Thickness te: thickness from the inner peripheral surface of the cylindrical portion 41b of the metal ring 41 to the surface S5. Thickness tf: thickness from the outer peripheral surface of the cylindrical portion 41b of the metal ring 41 to the surface S6.
[0063] When the eleventh portion 42b3 of the rubber 42 is present, the thickness td is substantially the thickness of the eleventh portion 42b3. When the eleventh portion 42b3 of the rubber 42 is not present, the thickness td is substantially 0. The thickness td is smaller than the thickness te. The thickness td is smaller than the thickness tf. The thickness te and the thickness tf may be the same or different. In the present embodiment, the thickness te is larger than the thickness tf.
[0064] Since the rubber 42 has higher rigidity than the sheet 43, the shape of the sheet 43 is maintained by the rubber 42. The shape of the middle portion 44 of the sheet 43 is also maintained by the metal ring 41.
[0065] The sheet 43 is formed of a nonwoven or woven fabric made of conductive fibers. The sheet 43 contains voids inside in its material state before the sliding member 15 is manufactured. After the sliding member 15 is manufactured, the rubber 42 also exists in the voids of the sheet 43. As will be described later, the sliding member 15 is manufactured by inserting the metal ring 41 and the sheet 43 into a mold, vulcanizing the rubber material constituting the rubber 42 to form a predetermined shape, and bonding the rubber material to the metal ring 41 and the sheet 43. Hereinafter, this manufacturing process will also be referred to as "vulcanization bonding." During this vulcanization bonding, the rubber 42 enters the voids in the sheet 43. During vulcanization bonding, the rubber 42 is easily bonded to the binder.
[0066] The fixed portion 45 of the sheet 43 is exposed on the surface of the sliding member 15 and contacts the annular groove 23 of the outer ring 11. The sliding portion 46 of the sheet 43 is exposed on the surface of the sliding member 15 and contacts the sliding member contact surface 33 of the inner ring 12. The multiple conductive fibers comprising the sheet 43 are in contact with one another, and the sheet 43 is conductive due to contact between the conductive fibers from the fixed portion 45 to the sliding portion 46. The sheet 43 is in contact with the outer ring 11 and the inner ring 12, and therefore the outer ring 11 and the inner ring 12 are electrically connected via the sheet 43. The conductive rubber 42 is in contact with the sheet 43 and also with the metal ring 41. The outer ring 11 and the inner ring 12 are electrically connected not only via the sheet 43 but also via the conductive metal ring 41 and rubber 42.
[0067] Therefore, the sliding member 15 of this embodiment can allow electric charge to escape from one of the fixed portion 45 and the sliding portion 46 to the other. Furthermore, the sliding member 15 of this embodiment can allow electric charge to escape from one of the member that fixes the fixed portion 45 and the member on which the sliding portion 46 slides to the other. The rolling bearing 10 of this embodiment can allow electric charge to escape from one of the outer ring 11 and the inner ring 12 to the other via the sliding member 15, making it possible to suppress electrolytic corrosion of the balls 13 and the outer ring raceway 21 and inner ring raceway 31 on which the balls 13 roll.
[0068] As shown in Fig. 2, the seat 43 is disposed closest to the second axial side (the bearing internal space K1 side) of the sliding member 15. On the other hand, the sliding member contact surface 33 provided on the inner ring 12 faces the first axial side (the bearing external space K2 side). This makes it easier for the sliding portion 46 of the seat 43 to come into contact with the sliding member contact surface 33. However, when the sliding member contact surface 33 faces the second axial side, the seat 43 of the sliding member 15 may be located closest to the first axial side of the sliding member 15.
[0069] [Method of Manufacturing Sliding Member] Fig. 6 is a cross-sectional view showing a molding die for a sliding member. Fig. 7 is a cross-sectional view showing an enlarged portion of the molding die for a sliding member. Fig. 8 is a cross-sectional view showing an enlarged portion of the molding die in an open state. The sliding member 15 is manufactured by compression molding (pressure molding) using a molding die 50. The molding die 50 for the sliding member 15 has an upper die 51 and a lower die 52. As shown in Fig. 8, the upper die 51 has a recess 51a, a protrusion 51b, an annular surface 51c, an annular surface 51d, and an annular surface 51e. The annular surfaces 51c, 51d, and 51e are surfaces facing the lower die 52. The recess 51a is recessed from the annular surface 51c on the radially inner side of the recess 51a and the annular surface 51d on the radially outer side thereof. The protrusion 51b protrudes from the radially inner annular surface 51e of the protrusion 51b and from the radially outer annular surface 51c. The lower mold 52 includes recesses 52a, 52b, 52c, and 52d, a mounting surface 52e, an annular surface 52g, and an annular surface 52h. The recesses 52a, 52b, 52c, and 52d and the mounting surface 52e are recessed integrally from the annular surfaces 52g and 52h. The recesses 52a, 52b, 52c, and 52d and the mounting surface 52e are collectively referred to as recess 52j.
[0070] The recesses 51a, 52a, 52b, and 52c, the mounting surface 52e, and the protrusion 51b are each annular and centered on the axis C2. The recesses 52d of the lower mold 52 are located at multiple locations spaced apart in the circumferential direction around the axis C2. The protrusion 51b of the upper mold 51 fits into the recess 52j of the lower mold 52. The recesses 52b and 52c of the lower mold 52 are formed by digging further down from the bottom surface of the recess 52a.
[0071] The recessed portion 51a is located radially inside the annular surface 51d and radially outside the annular surface 51c, and the protruding portion 51b is located radially inside the annular surface 51c and radially outside the annular surface 51e.
[0072] The recesses 52d are located radially inside the annular surface 52g and on both circumferential sides of a portion of the annular surface 52g, and are located radially outside the recesses 52b. The recesses 52b are located radially inside the portion of the annular surface 52g and the recesses 52d, and are located radially outside the mounting surface 52e. The mounting surface 52e is located radially inside the recesses 52b and radially outside the recesses 52c. The recesses 52c are located radially inside the mounting surface 52e and radially outside the recesses 52a. The recesses 52a are located radially inside the recesses 52c and radially outside the annular surface 52h.
[0073] In the lower mold 52, the mounting surface 52e protrudes from the recess 52b toward the upper mold 51, and protrudes from the recess 52c toward the upper mold 51. A surface on the first axial side of the annular portion 41a of the metal ring 41 is placed on this mounting surface 52e. In the lower mold 52, a restricting surface 52f is located between the recesses 52d adjacent in the circumferential direction. The outer peripheral surface of the cylindrical portion 41b of the metal ring 41 comes into contact with this restricting surface 52f, and the metal ring 41 is positioned in the radial direction.
[0074] An adhesive is applied to the surface of the metal ring 41. For example, the metal ring 41 is immersed in the adhesive to apply the adhesive to the surface of the metal ring 41. The metal ring 41 with the adhesive applied is placed on the placement surface 52e. As shown in FIG. 8 , the metal ring 41, the sheet 43, and the unvulcanized rubber material G are placed between the upper mold 51 and the lower mold 52, which are separated and opened. The unvulcanized rubber material G is formed in a sheet shape. The sheet 43 and the rubber material G are placed in an overlapping state between the upper mold 51 and the lower mold 52. Because the unvulcanized rubber material G has high adhesiveness, it is adhered to the sheet 43 by overlapping it on the sheet 43. This prevents misalignment between the sheet 43 and the rubber material.
[0075] The recess 51a of the upper mold 51 and the annular surface 52g, recess 52d, and recess 52b of the lower mold 52 form the third portion 42a3, the fourth portion 42a4, the fifth portion 42b, the tenth portion 42b2, the eleventh portion 42b3, and the seventh portion 42d of the rubber 42 shown in Fig. 2. The third portion 44b, the fourth portion 44c, the fifth portion 45a, and the sixth portion 45b of the sheet 43 fit into the recess 51a and are molded into a shape that fits along the inner surface of the recess 51a.
[0076] The recess 52j of the lower mold 52 and the annular surface 51c, protrusion 51b, and annular surface 51e of the upper mold 51 form the radially inner sides of the first portion 42a1, the second portion 42a2, the sixth portion 42c, the eighth portion 42e, the ninth portion 42f, and the seventh portion 42d of the rubber 42 shown in FIG. The first portion 44a1, the second portion 44a2, and the sliding portion 46 of the sheet 43 are sandwiched between the first portion 42a1, the second portion 42a2, and the sixth portion 42c of the rubber 42 and the annular surface 51c, protrusion 51b, and annular surface 51e of the upper mold 51, and are formed into shapes that conform to the annular surface 51c, protrusion 51b, and annular surface 51e. Therefore, shapes corresponding to the shapes of the annular surface 51c, protrusion 51b, and annular surface 51e of the upper mold 51 are formed in the rubber 42 and the sheet 43. The recess 52b of the lower mold 52 is a portion for molding the seventh portion 42d of the rubber 42 shown in Figure 2. The recess 52c is a portion for molding the eighth portion 42e of the rubber 42. The recess 52d is a portion for molding the tenth portion 42b2 of the rubber 42.
[0077] The sliding member 15 is manufactured by placing a metal ring 41, a sheet 43, and an unvulcanized rubber material G between an upper mold 51 and a lower mold 52, closing the upper mold 51 and the lower mold 52, and applying pressure and heat. The pressurized unvulcanized rubber material G flows within the mold 50 and fills the recesses 51a, 52a to 52d of the upper mold 51 and the lower mold 52. The unvulcanized rubber material G also fills the voids in the sheet 43. When heated in this state, the adhesive hardens, and the unvulcanized rubber material G becomes rubber 42. As the adhesive hardens and the unvulcanized rubber material G becomes vulcanized rubber 42, the metal ring 41, the sheet 43, and the rubber 42 become one unit. Unnecessary portions of the integrated unit are removed to form the sliding member 15. For example, the sliding member 15 is obtained by removing the rubber 42 and the sheet 43 along the cutting lines L1 and L2 shown in FIG. 6 . By inserting the unvulcanized rubber material G into the sheet 43 and vulcanizing it, the rigidity of the sheet 43 is increased and the sheet 43 and the rubber 42 are integrated together.
[0078] In the above manufacturing method, the metal ring 41 is positioned in the vertical direction by being placed on the mounting surface 52e of the lower mold 52. Furthermore, the convex portion 51b of the upper mold 51 narrows the vertical distance between the metal ring 41 and the upper mold 51, and the convex portion 51b presses the metal ring 41 from above via the sheet 43 and the rubber 42 (rubber material G). This prevents the metal ring 41 from floating up from the mounting surface 52e. Furthermore, the metal ring 41 is positioned in the radial direction by the restricting surface 52f of the lower mold 52.
[0079] When the sliding member 15 is molded using the mold 50, the rubber material G flows radially as indicated by the white arrows in FIG. 6 . This facilitates radial movement of the metal ring 41 within the mold 50. Furthermore, the flow of the rubber material G causes the rubber material G to flow between the mounting surface 52e and the annular portion 41a of the metal ring 41, making it easier for the metal ring 41 to lift up. The mold 50 of this embodiment can accurately position the metal ring 41 using the mounting surface 52e, the regulating surface 52f, and the protrusion 51b, while also restricting movement of the metal ring 41. This allows the rubber 42 and the sheet 43 to be fixed in appropriate positions relative to the metal ring 41. The sheet 43 is placed in the mold 50 along the upper mold 51. The rubber material G positioned on the metal ring 41 side of the sheet 43 moves toward the metal ring 41 without breaking the sheet 43. This prevents the rubber material G from breaking the sheet 43 and thus prevents loss of electrical conductivity.
[0080] When the sliding member 15 is molded in the mold 50, a small amount of rubber material G enters between the lower surface of the metal ring 41 and the mounting surface 52e, forming a thin film-like portion (ninth portion) 42f (see FIG. 2). A small amount of rubber material G also enters between the outer peripheral surface of the metal ring 41 and the restricting surface 52f, forming a thin film-like portion (eleventh portion) 42b3. However, these portions 42f and 42b3 do not necessarily have to be formed. If these portions 42f and 42b3 are not formed, the surface of the metal ring 41 will be exposed to the outside.
[0081] 2, the sliding member 15 according to the embodiment described above includes a metal ring 41, rubber 42, and a sheet 43. The sheet 43 is formed of conductive fiber, is fixed in contact with a first member (outer ring 11) made of steel, and is in slidable contact with a second member (inner ring 12) also made of steel.
[0082] The rubber 42 includes a first rubber portion (ninth portion of the rubber 42) 42f fixed to a surface on a first axial side of the metal ring 41, and a second rubber portion (first portion of the rubber 42) 42a1 fixed to a surface on a second axial side of the metal ring 41. The sliding member 15 includes at least the second rubber portion 42a1 of the first and second rubber portions 42f, 42a1. The sheet 43 includes a first sheet portion (first portion of the intermediate portion 44 of the sheet 43) 44a1 fixed to the second rubber portion 42a1.
[0083] In the sliding member 15, the first surface S1 on the first axial side is the surface on the first axial side of the metal ring 41 or the surface on the first axial side of the first rubber portion 42f. The second surface S2 on the second axial side is the surface on the second axial side of the second rubber portion 42a1 and / or the first sheet portion 44a1. The first surface S1 and the second surface S2 are disposed at positions overlapping each other in the radial and circumferential directions.
[0084] In the sliding member 15, the first thickness ta is the thickness from the surface of the first axial side of the metal ring 41 to the first surface S1. The second thickness tb is the thickness from the surface of the second axial side of the metal ring 41 to the second surface S2. The second thickness tb is greater than the first thickness ta.
[0085] Therefore, in the sliding member 15 according to the embodiment, the sheet 43, which is a nonwoven or woven fabric made of conductive fibers, can reduce electrical resistance and increase conductivity compared to an elastic material made of rubber with carbon fibers kneaded into it. Therefore, in the sliding member 15, the first member 11 and the second member 12 are electrically connected by the sheet 43, and an electric current can flow from one of the first member 11 and the second member 12 to the other via the sheet 43.
[0086] Furthermore, in the sliding member 15, the second thickness tb described above is greater than the first thickness ta. Therefore, the mold 50 for molding the sliding member 15 has a structure that presses the metal ring 41 in the axial direction (vertical direction), as shown in FIGS. 7 and 8 . Specifically, in the above embodiment, the mold 50 presses and supports the metal ring 41 from below with the mounting surface 52e. The mold 50 presses the metal tube 41 from above with the protrusion 51b. This prevents the metal ring 41 from shifting in position relative to the mold 50. Furthermore, because the rubber 42 is bonded to the entire first axial side of the sheet 43, the rubber can maintain the overall shape of the sheet 43. Furthermore, the sheet is not broken during manufacturing, preventing loss of conductivity.
[0087] 9 is an enlarged cross-sectional view of a sliding member according to the second embodiment. The rubber 42 of the sliding member 15 according to the second embodiment includes a twelfth portion 42a5 instead of the first portion 42a1 and the second portion 42a2 according to the first embodiment. The sheet 43 of the sliding member 15 according to the second embodiment includes a seventh portion 44a4 instead of the first portion 44a1, the second portion 44a2, and the stepped portion 44a3 of the intermediate portion 44 according to the first embodiment. In this embodiment, the twelfth portion 42a5 of the rubber 42, which has a substantially constant thickness, is fixed to the surface of the second axial side of the annular portion 41a of the metal ring 41. The seventh portion 44a4 of the sheet 43, which has a substantially flat shape and extends radially, is fixed to the second axial side of the twelfth portion 42a5.
[0088] In the present embodiment, the sliding member 15 includes the following "surface S7" and "thickness tg". Surface S7: the surface on the second axial side of the twelfth portion 42a5 of the rubber 42 and / or the seventh portion 44a4 of the sheet 43. Thickness tg: the thickness from the surface on the second axial side of the annular portion 41a of the metal ring 41 to the surface S7.
[0089] In this embodiment, the second surface of the sliding member 15 is formed by the surface S7, and the second thickness of the sliding member 15 is formed by the thickness tg. In this embodiment, substantially the same effects as in the first embodiment are achieved.
[0090] [Other embodiments] In the rolling bearing 10 of the above-described embodiment, the outer ring 11 is a fixed ring and the inner ring 12 is a rotating ring. However, the present invention may also be applicable to a case where the outer ring 11 is a rotating ring and the inner ring 12 is a fixed ring.
[0091] The sliding member 15 in the above embodiment is fixed to the outer ring 11, which is the first member, and is in slidable contact with the inner ring 12, which is the second member. However, in the present invention, the sliding member 15 may be fixed to the inner ring 12, which is the first member, and be in slidable contact with the outer ring 11, which is the second member.
[0092] In the sliding member 15 of the above embodiment, a synthetic resin is fixed as a binder to the conductive fibers that make up the sheet 43. On the other hand, in the sheet of the present invention, the conductive fibers that make up the sheet do not need to have a synthetic resin as a binder. The sliding member 15 of the above embodiment is used in the rolling bearing 10. However, the sliding member 15 of the present invention may be used in a device that is fixed to one of two members that move relatively and is in slidable contact with the other member.
[0093] In the above embodiment, the rolling bearing 10 is described as a deep groove ball bearing. However, in the present invention, the rolling bearing 10 may be an angular contact ball bearing, a roller bearing in which the rolling elements are rollers, or the like. The above embodiment is illustrative in all respects and is not restrictive. The scope of the present invention is defined by the claims, not the above embodiment, and includes all modifications within the scope of equivalents to the configurations described in the claims.
[0094] DESCRIPTION OF SYMBOLS 10: Rolling bearing 11: Outer ring (first member) 12: Inner ring (second member) 13: Rolling element 15: Sliding member 21: Outer ring raceway 31: Inner ring raceway 41: Metal ring 42: Rubber 42a1: First portion (second rubber portion) 42a2: Fourth portion (third rubber portion) 42f: Ninth portion (first rubber portion) 43: Seat 44a1: First portion (seat portion) 44a4: Seventh portion (seat portion) S1: Surface (first surface) S2: Surface (second surface) S7: Surface (second surface) ta: First thickness tb: Second thickness tg: Second thickness
Claims
1. The device includes a sheet, a rubber, and a metal ring. the sheet is formed of conductive fibers, is fixed in contact with a first member made of steel, and is in slidable contact with a second member made of steel; The rubber is a first rubber portion fixed to a surface of a first axial side of the metal ring; a second rubber portion fixed to a surface of the metal ring on a second side in the axial direction, The sheet is a sheet portion fixed to the second rubber portion; the first surface on the first axial side is a surface on the first axial side of the metal ring or a surface on the first axial side of the first rubber portion, the second surface on the second axial side is a surface on the second axial side of the second rubber portion and / or the sheet portion, the first surface and the second surface are disposed at positions overlapping each other in the radial direction and the circumferential direction, a first thickness is a thickness from a surface of a first side in an axial direction of the metal ring to the first surface; a second thickness is a thickness from a surface of a second axial side of the metal ring to the second surface, the second thickness is greater than the first thickness; the metal ring is spaced apart from the seat on a first axial side; The sliding member has a portion of the rubber disposed in the gap.
2. 2. The sliding member according to claim 1, wherein the rubber is adhered to the entire first axial side of the sheet.
3. an inner ring having an inner ring raceway; an outer ring having an outer ring raceway disposed radially outward of the inner ring raceway; a plurality of rolling elements rollably disposed between the inner ring raceway and the outer ring raceway; the sliding member according to claim 1 or 2, which is disposed radially between an axial end of the inner ring and an axial end of the outer ring, one of the inner ring and the outer ring is the first member, the other of the inner ring and the outer ring is the second member.