Rolling bearing

Abstract

To suppress the current flowing between an outer ring and an inner ring via rolling elements in a rolling bearing, thereby preventing the occurrence of electrical corrosion.SOLUTION: A first rolling bearing 10A includes an outer ring 11, an inner ring 12, rolling elements 13, a conductive member 15 fixed to the outer ring 11 and slidingly contacting the inner ring 12, and a covering member 50 that covers an outer circumferential surface 11a and an end face 11b of the outer ring 11 and an annular groove 23 in the outer ring 12 serving as a mounting portion for the conductive member 15. The covering member 50 includes an insulating layer 51 in contact with the outer ring 11, and a conductive layer 52 arranged on the side opposite to the side of the insulating layer 51 that contacts the outer ring 11. The insulating layer 51 is insulating, and the conductive layer 52 is conductive.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to rolling bearings. [Background technology]

[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 equipped with a conductive member (conductive sliding member) that allows current to flow between the outer ring and the inner ring. The conductive member is fixed to the outer ring and contacts the inner ring. The inner ring is electrically connected to the outer ring through the conductive member. By bringing the conductive member into contact with the outer ring and the inner ring, the rolling bearing can suppress electrolytic corrosion of the raceways of the outer ring and the inner ring. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2023 / 233649 Summary of the Invention [Problem to be solved by the invention]

[0004] The rolling bearing disclosed in Patent Document 1 uses a conductive member to ensure a path (conductive path) for current to flow between the outer ring and the inner ring. However, if the rolling elements of the rolling bearing are made of metal, current flows between the outer ring and the inner ring via the rolling elements. As a result, in the rolling bearing, electrolytic corrosion may occur in the raceways of the outer ring and the inner ring and in the rolling elements due to the current flowing via the rolling elements. Therefore, although the rolling bearing can suppress the progression of electrolytic corrosion, it cannot suppress the occurrence of electrolytic corrosion due to the current flowing via the rolling elements. An object of the present disclosure is to suppress electrolytic corrosion that occurs in a rolling bearing due to current flowing between an outer ring and an inner ring via rolling elements. [Means for solving the problem]

[0005] The rolling bearing disclosed herein comprises an outer ring, an inner ring, rolling elements, a conductive member fixed to the outer ring and in sliding contact with the inner ring, and a covering member that covers the outer peripheral surface of the outer ring, the end faces of the outer ring, and the mounting portion of the conductive member on the outer ring, wherein the covering member includes a first layer that contacts the outer ring and a second layer that is arranged on the side of the first layer opposite to the side that contacts the outer ring, and the first layer is insulating and the second layer is conductive.

[0006] The rolling bearing of the present disclosure comprises an outer ring, an inner ring, rolling elements, a conductive member fixed to the inner ring and in sliding contact with the outer ring, and a covering member that covers the inner surface of the inner ring, the end faces of the inner ring, and the mounting portion of the conductive member on the inner ring, wherein the covering member includes a first layer that contacts the inner ring and a second layer that is arranged on the side of the first layer opposite to the side that contacts the inner ring, and the first layer is insulating and the second layer is conductive.

[0007] According to the present disclosure, in a rolling bearing, it is possible to suppress electrolytic corrosion caused by current flowing between the outer ring and the inner ring via the rolling elements. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a cross-sectional view showing a rolling bearing according to a first embodiment of the present disclosure. [Figure 2] FIG. 2 is an enlarged cross-sectional view showing a mounting portion of the outer ring for a conductive member. [Figure 3] FIG. 3 is a partially enlarged cross-sectional view of the conductive member. [Figure 4] FIG. 4 is an enlarged cross-sectional view showing a modified example of the mounting portion of the conductive member on the outer ring. [Figure 5] FIG. 5 is a cross-sectional view showing a rolling bearing according to a second embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0009] <Details of the embodiment of the present disclosure> Hereinafter, embodiments of the invention of the present disclosure will be described. Fig. 1 is a cross-sectional view showing a rolling bearing 10 according to a first embodiment of the present disclosure. In the following description, the rolling bearing 10 according to the first embodiment will also be referred to as a first rolling bearing 10A. In the following description, when the term "rolling bearing 10" is simply used, a configuration common to the first rolling bearing 10A and rolling bearings according to other embodiments described later (see second rolling bearing 10B shown in Fig. 5) will be described.

[0010] The first rolling bearing 10A supports a rotating shaft S1 of a motor mounted on, for example, an electric vehicle or a hybrid vehicle.

[0011] The rolling bearing 10 includes an outer ring 11, an inner ring 12, a plurality of rolling elements 13, a cage 14, a conductive member 15, and a covering member 50. In this embodiment, the rolling elements 13 are balls. The rolling bearing 10 is a deep groove ball bearing. In the following description, the rolling elements 13 will also be referred to as balls 13.

[0012] The outer ring 11 and the inner ring 12 are made of a steel material such as bearing steel. As the bearing steel, high-carbon chromium bearing steel (for example, SUJ2 or SUJ3 as specified in the JIS standard) can be used. However, the outer ring 11 and the inner ring 12 may also be made of other steel materials such as carburized bearing steel, carbon steel, chromium steel, or stainless steel.

[0013] The outer ring 11 and the inner ring 12 are arranged concentrically. In this embodiment, the central axes of the outer ring 11 and 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 a first axial side, and the right side of FIG. 1 is defined as a second axial side.

[0014] In the first rolling bearing 10A, the outer ring 11 is a fixed ring and the inner ring 12 is a rotating ring. The outer ring 11 is attached to a housing H1 of the motor. The inner ring 12 is fitted onto and fixed to the outer peripheral surface of a rotating shaft S1. In Fig. 1, the housing H1 and the rotating shaft S1 are indicated by virtual lines (two-dot chain lines).

[0015] The outer ring 11 has an outer ring raceway 21 on its inner peripheral surface. The outer ring 11 has shoulders 22 on both axial sides of the outer ring raceway 21. The balls 13 roll on the outer ring raceway 21.

[0016] In the first rolling bearing 10A, the outer ring 11 has two annular grooves 23. The annular grooves 23 are each provided between the shoulder 22 and the axial end face 11b of the outer ring 11. The annular grooves 23 have an annular groove shape that is continuous in the circumferential direction.

[0017] In the first rolling bearing 10A, the conductive member 15 is attached to the annular groove 23 located on a first axial side of the outer ring 11. On the other hand, the conductive member 15 is not attached to the annular groove 23 located on a second axial side of the outer ring 11. The conductive member 15 may also be attached to the annular groove 23 located on the second axial side of the outer ring 11. When the conductive member 15 is not attached to the annular groove 23 located on the second axial side of the outer ring 11, the annular groove 23 located on the second side may be omitted.

[0018] The inner ring 12 has an inner ring raceway 31 on its outer circumferential surface. The inner ring 12 has shoulders 32 on both axial sides of the inner ring raceway 31. The balls 13 roll on this inner ring raceway 31.

[0019] In the first rolling bearing 10A, the inner ring 12 has two contact surfaces 33. The contact surfaces 33 are respectively provided between the shoulders 32 and the axial end face 12b of the inner ring 12. The contact surfaces 33 are provided annularly around the entire circumference of the inner ring 12. The contact surfaces 33 are groove-shaped in a cross section including the central axis of the inner ring 12. The radially inner end of the conductive member 15 is in contact with the contact surfaces 33.

[0020] 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 by an annular cage 14 at intervals in the circumferential direction.

[0021] 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. The pockets 18 are spaces on the first axial side of the annular body 16 between two circumferentially adjacent horns 17. The balls 13 are housed in the pockets 18. The pockets 18 are open on the first axial side.

[0022] The conductive member 15 is formed in an annular shape. In the first rolling bearing 10A, the conductive member 15 is fixed to the outer ring 11 and is in sliding contact with the inner ring 12. The conductive member 15 is fixed to the outer ring 11 by fitting its radially outer end into an annular groove 23 on the first axial side of the outer ring 11. The radially inner end of the conductive member 15 contacts the contact surface 33 of the inner ring 12. The conductive member 15 is provided only on the first axial side of the rolling bearing 10, and is not provided on the second axial side of the rolling bearing 10. Therefore, the bearing internal space K1, which is the annular space between the outer ring 11 and the inner ring 12 and in which the balls 13 are present, opens to the second axial side. The conductive member 15 separates the bearing internal space K1, in which the balls 13 are present, from the bearing external space K2, which is the space on the first axial side of the rolling bearing 10.

[0023] [Specific structure of conductive material] Fig. 2 is an enlarged cross-sectional view showing the mounting portion of the conductive member on the outer ring. Fig. 3 is a partially enlarged cross-sectional view of the conductive member. As shown in Figs. 1 to 3, conductive member 15 has a core material 41, an elastic material 42, and a sheet 43. Core material 41, elastic material 42, and sheet 43 are all annular. Core material 41, elastic material 42, and sheet 43 are bonded to each other to form a single unit.

[0024] The core material 41 is a metal ring. The core material 41 is formed from a metal such as a galvanized steel plate or stainless steel. The core material 41 is formed by processing a plate material. The core material 41 includes an annular portion 41a formed in an annular ring shape and a cylindrical portion 41b formed in a cylindrical shape. 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 radially outer end of the annular portion 41a. The cylindrical portion 41b extends from the radially outer end of the annular portion 41a to a second axial side (toward the bearing internal space K1).

[0025] The elastic material 42 is made of conductive rubber. The elastic material 42 is manufactured by blending a conductive material, such as carbon black or metal powder, into synthetic rubber, for example.

[0026] The sheet 43 is made of a nonwoven fabric or a woven fabric made of conductive fibers. In this embodiment, the sheet 43 uses carbon fibers as the conductive fibers. However, the conductive fibers may be made of other materials, such as fibers made of conductive metals such as copper or nickel. The electrical resistance of the sheet 43 is lower than the electrical resistance of the elastic material 42. 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 with the binder fixed thereto.

[0027] The sheet 43 integrally includes an intermediate portion 44, a fixed portion 45, and a sliding portion 46. The intermediate portion 44 is a portion that is mainly bonded to the core material 41. The intermediate portion 44 has a first portion 44a and a second portion 44b. The first portion 44a extends in the radial direction. A radially outer portion of the first portion 44a is bonded to a side surface of the annular portion 41a of the core material 41 on the second axial side (the side of the bearing external space K2). A radially inner portion of the first portion 44a is a portion that is not the radially outer portion of the first portion 44a and is not bonded to the core material 41. The second portion 44b is bonded to a portion of the outer peripheral surface of the cylindrical portion 41b of the core material 41. The shape of the intermediate portion 44 of the sheet 43 is mainly maintained by the core material 41 and the elastic material 42.

[0028] The fixing portion 45 of the seat 43 is formed continuously with the second portion 44b of the intermediate portion 44. As shown in FIG. 2, the fixing portion 45 has a third portion 45a and a fourth portion 45b. The third portion 45a curves from the end of the second portion 44b of the intermediate portion 44 on the second axial side (the side of the bearing internal space K1) and extends further radially outward. The fourth portion 45b curves from the radially outer end of the third portion 45a toward the first axial side.

[0029] The second axial end of the third portion 45 a and the radially outer end of the fourth portion 45 b are in direct contact with the conductive layer 52 of the covering member 50 .

[0030] 1 and 3, the sliding portion 46 of the seat 43 is formed as a continuous radially inner portion of the first portion 44a, which is the intermediate portion 44. The sliding portion 46 has a fifth portion 46a, which is a radially inner portion of the first portion 44a. The radially inner surface of this fifth portion 46a is in direct contact with the contact surface 33 of the inner ring 12.

[0031] As shown in Fig. 1, the elastic material 42 is provided over substantially the entire side surface of the first axial side of the sheet 43. As shown in Fig. 2, a portion 42a of the elastic material 42 is provided in an area surrounded by the second portion 44b, the third portion 45a, and the fourth portion 45b of the sheet 43. As shown in Figs. 2 and 3, the other portion 42b of the elastic material 42 is provided with a substantially constant thickness along the side surface of the first portion 44a of the sheet 43 on the first axial side.

[0032] 2, another part 42c of the elastic material 42 covers the side surfaces on the second axial side of the third part 45a and the fourth part 45b of the sheet 43. Furthermore, another part 42d of the elastic material 42 is provided so as to cover the end face on the second axial side of the cylindrical part 41b of the core material 41.

[0033] Because the elastic material 42 has higher rigidity than the sheet 43, the shape of the sheet 43 is maintained not only by the core material 41 but also by the elastic material 42. Furthermore, a portion 42a of the elastic material 42 elastically supports a fourth portion 45b of the sheet 43 from the radially inner side. The cylindrical portion 41b of the core material 41 supports the portion 42a of the elastic material 42 from the radially inner side. Therefore, the fixed portion (radially outer end portion) of the sheet 43 is pressed against the annular groove 23 of the outer ring 11 by the elasticity of the portion 42a of the elastic material 42 supported by the cylindrical portion 41b of the core material 41, and is brought into secure contact with the annular groove 23.

[0034] The sheet 43 includes a nonwoven fabric or a woven fabric made of conductive fibers. The sheet 43 includes voids therein in the material state before the conductive member 15 is manufactured. After the conductive member 15 is manufactured, the elastic material 42 also exists in the voids of the sheet 43.

[0035] [Specific structure of the covering material] 1 and 2 is a laminated film including an insulating layer 51 and a conductive layer 52. The insulating layer 51 is made of a film-like base material. The conductive layer 52 is made of a conductive film formed on one surface (the front surface or the back surface) of the base material having a front surface and a back surface.

[0036] In the first rolling bearing 10A, the covering member 50 includes an insulating layer 51 that contacts the outer ring 11, and a conductive layer 52 that is arranged on the side of the insulating layer 51 opposite to the side that contacts the outer ring 11. The covering member 50 covers at least the outer peripheral surface 11a, the end face 11b, and the annular groove 23 of the outer ring 11.

[0037] In the rolling bearing 10 of the present disclosure, the material constituting the insulating layer 51 is a thermoplastic resin. The covering member 50 is disposed so as to cover the outer peripheral surface 11a, end face 11b, and annular groove 23 of the outer ring 11, and is then heated to shrink and harden. This causes the covering member 50 to adhere closely to the outer peripheral surface 11a, end face 11b, and annular groove 23.

[0038] Specifically, examples of materials that can be used to form the insulating layer 51 include polyethylene (low-density polyethylene, linear low-density polyethylene, high-density polyethylene, and cyclic polyolefin), polypropylene, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, copolymers of ethylene and unsaturated carboxylic acid (e.g., acrylic acid, methacrylic acid, and maleic acid), copolymers of ethylene and unsaturated carboxylic acid ester (e.g., methyl acrylate, methyl methacrylate, methyl maleate, and dimethyl maleate), polyesters such as polyethylene terephthalate, and polyamide. Note that the insulating layer 51 may also be formed of rubber, a solid lubricant insulating coating, or the like.

[0039] The conductive layer 52 is provided, for example, by depositing, applying, or laminating various metals and conductive polymers on one surface (front or back) of the film-like substrate that constitutes the insulating layer 51. Examples of the various metals that can be used include silver and ITO (indium tin oxide). Examples of the conductive polymer that can be used include PEDOT / PSS.

[0040] The covering member 50 having such a configuration can be manufactured easily and inexpensively. Therefore, by employing the covering member 50, the rolling bearing 10 of the present disclosure can ensure electrical conductivity between the outer ring 11 and the inner ring 12 and suppress the occurrence of electrolytic corrosion with an inexpensive configuration.

[0041] [About the conduction path] 1 to 3, most of the fixing portion 45 of the sheet 43 is covered with the elastic material 42. On the other hand, at least a part of the fixing portion 45 of the sheet 43 (particularly the radially outer end portion of the sheet 43) is exposed on the surface of the conductive member 15.

[0042] In the first rolling bearing 10A, a portion of the fixed portion 45 of the sheet 43 exposed on the surface comes into contact with the covering member 50 (specifically, the conductive layer 52) that covers the annular groove 23. The insulating layer 51 prevents the fixed portion 45 from coming into direct contact with the annular groove 23. At least a portion (particularly the radially inner end of the sheet 43) of the sliding portion 46 of the sheet 43 is exposed on the surface of the conductive member 15. The portion of the sliding portion 46 of the sheet 43 exposed on the surface comes into contact with the contact surface 33 of the inner ring 12. The sheet 43 comes into contact with the conductive layer 52 and the inner ring 12. Therefore, the conductive layer 52 and the inner ring 12 are electrically connected via the sheet 43. The conductive core material 41 and the elastic material 42 also come into contact with the sheet 43. The conductive layer 52 and the inner ring 12 are electrically connected via the conductive core material 41 and the elastic material 42 in addition to the sheet 43.

[0043] Therefore, the rolling bearing 10 of this embodiment can dissipate electric charges from one of the outer ring 11 and the inner ring 12 to the other of the outer ring 11 and the inner ring 12 via the conductive layer 52 and the conductive 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.

[0044] Meanwhile, insulating layer 51 of covering member 50 suppresses current flowing between outer ring 11 and inner ring 12 via balls 13. For this reason, rolling bearing 10 of this embodiment ensures a path (conductive path) for current to flow between outer ring 11 and inner ring 12 via conductive layer 52 and conductive member 15, and also blocks the path for current to flow between outer ring 11 and inner ring 12 via balls 13 by insulating layer 51. As a result, rolling bearing 10 of the present disclosure can suppress electrolytic corrosion of balls 13 and the outer ring raceway 21 and inner ring raceway 31 on which balls 13 roll, while ensuring the necessary conductivity.

[0045] [Insulating layer and conductive layer coverage] Fig. 4 is an enlarged cross-sectional view showing a modified example of the mounting portion of the conductive member on the outer ring. In the rolling bearing 10 shown in Figs. 1 and 2, the insulating layer 51 of the covering member 50 extends in the axial direction to a position covering the shoulder 22 of the outer ring 11. This makes it possible to prevent current flowing through the conductive layer 52 from flowing to the outer ring raceway 21 via the shoulder 22. In the rolling bearing 10 shown in Figs. 1 and 2, the conductive layer 52 of the covering member 50 extends to a position covering the axial end face of the annular groove 23 of the outer ring 11. This makes it possible to reliably ensure conductivity between the conductive member 15 fixed in the annular groove 23 and the conductive layer 52.

[0046] Thus, in the first rolling bearing 10A of this embodiment, the insulating layer 51 extends in the axial direction to a position that covers the shoulder 22 of the outer ring 11. With this configuration, it is possible to reliably suppress the current that flows between the outer ring 11 and the inner ring 12 via the balls 13.

[0047] Note that by covering the annular groove 23, the conductive layer 52 can ensure electrical continuity with the conductive member 15 fixed in the annular groove 23. Therefore, the conductive layer 52 does not need to extend to a position covering the shoulder 22. However, the conductive layer 52 is a conductive film formed by techniques such as vapor deposition or coating, and it may be difficult to remove only a portion of the conductive layer 52 from the insulating layer 51. For this reason, as shown in FIG. 4 , in the rolling bearing 10 of the present disclosure, the conductive layer 52 of the covering member 50 may be provided so as to extend axially to a position covering the shoulder 22 of the outer ring 11, similar to the insulating layer 51. In this case, special processing such as removing a portion of the conductive layer 52 from the insulating layer 51 is not required, making the covering member 50 easier to handle. This configuration makes it possible to more easily provide the covering member 50 in the rolling bearing 10.

[0048] According to the first rolling bearing 10A of this embodiment, it is possible to ensure conductivity between the outer ring 11 and the inner ring 12 and suppress the current flowing between the outer ring 11 and the inner ring 12 via the balls 13 without increasing the axial dimension. This makes it possible to suppress electrolytic corrosion in the rolling bearing 10 caused by the current flowing between the outer ring 11 and the inner ring 12 via the balls 13.

[0049] [Regarding the rolling bearing according to the second embodiment of the present disclosure] 5 is a cross-sectional view showing a rolling bearing according to a second embodiment of the present disclosure. In the following description, the rolling bearing 10 according to the second embodiment is also referred to as a second rolling bearing 10B. In the following description, the second rolling bearing 10B will be described in terms of configurations that differ from the first rolling bearing 10A described above, and a description of common configurations will be omitted.

[0050] In the second rolling bearing 10B, the outer ring 11 is a rotating ring, and the inner ring 12 is a fixed ring. The outer ring 11 is attached to a rotatable housing H2. The inner ring 12 is fitted onto the outer peripheral surface of a non-rotatable shaft S2 and is fixed to said outer peripheral surface. In Figure 5, the housing H2 and the shaft S2 are indicated by virtual lines (two-dot chain lines).

[0051] In the second rolling bearing 10B, the outer ring 11 has two contact surfaces 24. The contact surfaces 24 are respectively provided between the shoulders 22 and the end face 11b of the outer ring 11. The contact surfaces 24 are provided annularly around the entire circumference of the outer ring 11. The contact surfaces 24 are groove-shaped in a cross section including the central axis of the outer ring 11. The radially outer end of the conductive member 15 contacts the contact surfaces 24.

[0052] In the second rolling bearing 10B, the inner ring 12 has two annular grooves 34. The annular grooves 34 are provided between the shoulder 32 and the end face 12b of the inner ring 12, respectively.

[0053] In the second rolling bearing 10B, the conductive member 15 is attached to an annular groove 34 arranged on a first axial side of the inner ring 12. On the other hand, the conductive member 15 is not attached to an annular groove 34 arranged on a second axial side of the inner ring 12. Note that the conductive member 15 may also be attached to annular groove 34 arranged on the second axial side of the inner ring 12. When the conductive member 15 is not attached to the annular groove 34 arranged on the second axial side, the annular groove 34 arranged on the second side may be omitted.

[0054] In the second rolling bearing 10B, the conductive member 15 is fixed to the inner ring 12 and is in sliding contact with the outer ring 11. Specifically, the conductive member 15 is fixed to the inner ring 12 by having its radially inner end fitted into an annular groove 34 on the first axial side of the inner ring 12. The radially outer end of the conductive member 15 is in contact with the contact surface 24 of the outer ring 11.

[0055] In the second rolling bearing 10B, the covering member 50 includes an insulating layer 51 that contacts the inner ring 12, and a conductive layer 52 that is arranged on the side of the insulating layer 51 opposite to the side that contacts the inner ring 12. The covering member 50 covers at least the inner circumferential surface 12a, the end face 12b, and the annular groove 34 of the inner ring 12.

[0056] In the second rolling bearing 10B, part of the fixed portion 45 of the seat 43 contacts the covering member 50 (specifically, the conductive layer 52) that covers the annular groove 34. The insulating layer 51 prevents the fixed portion 45 from coming into direct contact with the annular groove 34. Furthermore, at least part of the sliding portion 46 of the seat 43 (particularly the radially inner end of the seat 43) is exposed on the surface of the conductive member 15. The part of the sliding portion 46 of the sheet 43 that is exposed on the surface contacts the contact surface 24 of the outer ring 11. The sheet 43 contacts the conductive layer 52 and the outer ring 11. Therefore, the conductive layer 52 and the outer ring 11 are electrically connected via the sheet 43. The conductive core material 41 and elastic material 42 also contact the sheet 43. The conductive layer 52 and the outer ring 11 are electrically connected via the conductive core material 41 and elastic material 42 in addition to the sheet 43.

[0057] According to the second rolling bearing 10B of this embodiment, it is possible to ensure conductivity between the outer ring 11 and the inner ring 12 and suppress the current flowing between the outer ring 11 and the inner ring 12 via the balls 13 without increasing the axial dimension. This makes it possible to suppress electrolytic corrosion in the rolling bearing 10 caused by the current flowing between the outer ring 11 and the inner ring 12 via the balls 13.

[0058] In the second rolling bearing 10B shown in Fig. 5, the insulating layer 51 extends in the axial direction to a position that covers the shoulder 32 of the inner ring 12. This configuration reliably suppresses the current that flows between the outer ring 11 and the inner ring 12 via the balls 13. This makes it possible to prevent the current flowing through the conductive layer 52 from flowing to the inner ring raceway 31 via the shoulder 32.

[0059] 5, the conductive layer 52 extends to a position that covers the axial end face of the annular groove 34 of the inner ring 12. This makes it possible to reliably ensure conduction between the conductive member 15 fixed to the annular groove 34 and the conductive layer 52.

[0060] [Other embodiments] In the above embodiment, the rolling bearing 10 is 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. [Explanation of symbols]

[0061] 10: Rolling bearings 11: Outer ring 11a: Outer surface 11b: End face 12: Inside 12a: Inner surface 12b: End face 13: Ball (rolling element) 15: Conductive material 22: Shoulder (of outer ring) 23: Annular groove (mounting part) 32: (inner) shoulder 33: Annular groove (mounting part) 50: Covering material 51: Insulating layer (first layer) 52: Conductive layer (second layer)

Claims

1. the bearing comprises an outer ring, an inner ring, rolling elements, a conductive member fixed to the outer ring and in sliding contact with the inner ring, and a covering member covering an outer peripheral surface of the outer ring, an end face of the outer ring, and an attachment portion of the outer ring for the conductive member, the covering member includes a first layer in contact with the outer ring, and a second layer disposed on the side of the first layer opposite to the side in contact with the outer ring, the first layer has insulating properties; The rolling bearing, wherein the second layer is electrically conductive.

2. the bearing comprises an outer ring, an inner ring, rolling elements, a conductive member fixed to the inner ring and in sliding contact with the outer ring, and a covering member covering an inner circumferential surface of the inner ring, an end face of the inner ring, and an attachment portion of the inner ring for the conductive member, the covering member includes a first layer in contact with the inner ring and a second layer disposed on an opposite side of the first layer from a side in contact with the inner ring, the first layer has insulating properties; The rolling bearing, wherein the second layer is electrically conductive.

3. 2. The rolling bearing according to claim 1, wherein the first layer extends to a position covering a shoulder of the outer ring.

4. 3. The rolling bearing according to claim 2, wherein the first layer extends to a position covering a shoulder of the inner ring.

5. the first layer is composed of a film-like substrate, 3. The rolling bearing according to claim 1, wherein the second layer is formed of a conductive film formed on one surface of the substrate.

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