Rolling bearing

Abstract

To provide a rolling bearing that achieves high performance in resistance to electrical corrosion.SOLUTION: A rolling bearing 1 has a metallic inner ring 2, a metallic outer ring 3, rolling elements 4 arranged between the inner ring 2 and the outer ring 3, and a conductive seal 6 for sealing the internal space between the inner ring 2 and the outer ring 3. The conductive seal 6 comprises a conductive rubber 61 and a plate-like core metal 62, wherein an end on the inner ring 2 side and an end on the outer ring 3 side of the conductive rubber 61 are held against the inner ring 2 and the outer ring 3 by the restoring force of the conductive rubber 61. The core metal 62 is fixed to the rolling element 4 side of the conductive rubber 61, and at a bent portion 621 formed by bending an end of the core metal 62 on the outer ring 3 side, a plate face of the core metal 62 directly contacts the outer ring 3.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a rolling bearing. [Background technology]

[0002] A rolling bearing is an annular bearing component with rolling elements disposed between an inner ring and an outer ring. Fig. 4 is a perspective view of a rolling bearing 100. Fig. 5 is a diagram showing an example of the configuration of the rolling bearing 100 of Fig. 4, showing a cross section perpendicular to the circumferential direction of the rolling bearing 100. In addition to the inner ring 20, outer ring 30, and rolling elements 40 described above, the main parts of the rolling bearing 100 are also equipped with a cage 50, seals 60, and grease 70.

[0003] The inner ring 20 and the outer ring 30 are annular members. Rolling surfaces 201 and 301 that accommodate spherical rolling elements 40 are formed on the opposing surfaces of the inner ring 20 and the outer ring 30, respectively. The rolling surfaces 201 and 301 are surfaces on which the rolling elements 40 roll. The cage 50 holds the rolling elements 40 arranged between the rolling surfaces 201 and 301 so that they can roll.

[0004] Seal 60 seals the internal space between inner ring 20 and outer ring 30 on both axial sides of rolling bearing 100. The axial direction of rolling bearing 100 corresponds to the left-right direction in Figure 5. Seal 60 has rubber 601 and a core metal 602. The end of rubber 601 on the inner ring 20 side and the end on the outer ring 30 side are held by the inner ring 20 and the outer ring 30, respectively, by the restoring force associated with the elasticity of rubber 601. In this way, seal 60 fits between the inner ring 20 and the outer ring 30. Grease 7 is filled in the internal space sealed by seal 60.

[0005] In electric vehicles and the like, rolling bearings 100 are used to support the rotating shaft of inverter-driven motors, etc. However, when electricity flows between the inner ring 20 or the outer ring 30 and the rolling elements 40, electrolytic corrosion occurs on the rolling surfaces 201, 301 of the inner ring 20 or the outer ring 30, which can cause abnormal noise and the like.

[0006] One technique for preventing electrolytic corrosion is to impart conductivity to the rolling bearing 100 and pass electricity through a route that does not pass through the rolling elements 40. Specific examples of this include a technique in which electricity is passed through a conductive brush, such as a carbon brush, that is arranged separately from the main body of the rolling bearing 100, and a technique in which electricity is passed between the inner ring 20 and the outer ring 30 via a conductive seal 60, as disclosed in Patent Document 1. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-7738 Summary of the Invention [Problem to be solved by the invention]

[0008] However, carbon brushes used as conductive brushes are very expensive and have issues such as dust generation due to wear and complicated installation structures. In addition, the conductive seal 60 uses rubber 601 containing carbon black, etc., but in order to improve the galvanic corrosion resistance, it is necessary to further reduce the electrical resistance of the seal 60.

[0009] In view of the above problems, an object of the present invention is to provide a rolling bearing having high resistance to electrolytic corrosion. [Means for solving the problem]

[0010] In order to solve the above problems, the present invention provides a rolling bearing having metal inner and outer rings, rolling elements arranged between the inner and outer rings, and a conductive seal that seals the internal space between the inner and outer rings, wherein the conductive seal comprises conductive rubber and a plate-shaped core metal, the end of the conductive rubber on the inner ring side and the end of the conductive rubber on the outer ring side are held to the inner and outer rings by the restoring force of the conductive rubber, the core metal is attached to the rolling element side of the conductive rubber, and the plate surface of the core metal is in direct contact with the outer ring at a bent portion formed by bending the end of the core metal on the outer ring side.

[0011] The bent portion is preferably formed by bending the end of the core metal on the outer ring side by 180 degrees.

[0012] It is desirable that the inner ring side end and the outer ring side end of the conductive rubber are accommodated in grooves formed in the inner ring and the outer ring, and that the plate surface of the core metal at the bent portion contacts the wall surface of the groove formed in the outer ring. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide a rolling bearing having high resistance to electrolytic corrosion. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a diagram showing an example of the configuration of a rolling bearing 1 according to an embodiment of the present invention. [Figure 2] FIG. 1 is a diagram showing a reference example of a rolling bearing. [Figure 3] 2 is a diagram showing a modified example of the rolling bearing 1 of FIG. [Figure 4] FIG. 1 is a perspective view showing a rolling bearing 100. [Figure 5] 5 is a diagram showing an example of the configuration of the rolling bearing 100 of FIG. 4. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

[0016] Fig. 1 is a diagram showing an example of the configuration of a rolling bearing 1 according to an embodiment of the present invention. The rolling bearing 1 is an annular bearing member similar to that shown in Fig. 4, with rolling elements 4 arranged between an inner ring 2 and an outer ring 3. Like Fig. 5, Fig. 1 shows a cross section perpendicular to the circumferential direction of the rolling bearing 1.

[0017] The rolling bearing 1 comprises, as its main components, a cage 5, a conductive seal 6, and grease 7 in addition to the inner ring 2, outer ring 3, and rolling elements 4 described above.

[0018] The inner ring 2 and the outer ring 3 are annular members made of metal. The outer ring 3 is arranged on the outside of the inner ring 2. The rolling elements 4 are spherical members made of metal. Multiple rolling elements 4 are arranged at intervals around the circumferential direction of the rolling bearing 1. Rolling surfaces 21 and 31 that accommodate the rolling elements 4 are formed on the opposing surfaces of the inner ring 2 and the outer ring 3, respectively. The rolling surfaces 21 and 31 are surfaces that allow the rolling elements 4 to roll, and have concave curved surfaces that correspond to the diameter of the rolling elements 4. The rolling elements 4 are arranged between the rolling surfaces 21 and 31.

[0019] The cage 5 holds the rolling elements 4 arranged between the rolling surfaces 21, 31 so that they can roll. The cages 5 are metal members provided on both sides of the rolling elements 4 in the axial direction of the rolling bearing 1. The axial direction of the rolling bearing 1 corresponds to the left-right direction in Figure 1. The surface of the cage 5 facing the rolling elements 4 has a concave curved surface that corresponds to the diameter of the rolling elements 4.

[0020] The conductive seals 6 seal the internal space between the inner ring 2 and the outer ring 3 on both axial sides of the rolling bearing 1. The internal space sealed by the conductive seals 6 is filled with grease 7.

[0021] The conductive seal 6 has a conductive rubber 61 and a core metal 62 .

[0022] The conductive rubber 61 is rubber containing conductive materials such as carbon black and metal powder. The end of the conductive rubber 61 on the inner ring 2 side and the end on the outer ring 3 side are housed in grooves 22, 32 provided in the opposing surfaces of the inner ring 2 and outer ring 3, respectively. Grooves 22, 32 are provided on both sides of the rolling surfaces 21, 31 in the axial direction of the rolling bearing 1.

[0023] The end of conductive rubber 61 on the inner ring 2 side and the end on the outer ring 3 side press against the wall surfaces of grooves 22, 32 due to the restoring force caused by the elasticity of conductive rubber 61. This causes the end of conductive rubber 61 on the inner ring 2 side and the end on the outer ring 3 side to be held by inner ring 2 and outer ring 3, respectively. As a result, conductive seal 6 fits between inner ring 2 and outer ring 3, sealing the internal space between them.

[0024] The core metal 62 is a plate-like member that supports the conductive rubber 61, and is made of a metal plate. The core metal 62 is provided on the rolling element 4 side of the conductive rubber 61. The end of the core metal 62 on the outer ring 3 side is bent 180 degrees by hemming to form a bent portion 621. In this embodiment, at this bent portion 621, the plate surface of the core metal 62 directly contacts the wall surface of the groove 32 in the outer ring 3. The plate surface is a surface that forms the front and back of the plate material (plate-shaped core metal 62), and is a surface that is perpendicular to the thickness direction of the plate material.

[0025] In this embodiment, the outer ring 3 and the core 62 are electrically integrated by bringing the core 62 into direct contact with the outer ring 3. This reduces the electrical resistance of the conductive seal 6 and improves the electrolytic corrosion resistance of the rolling bearing 1.

[0026] Fig. 2 is a cross-sectional view similar to Fig. 1 showing a reference example of a rolling bearing. If, as shown in Fig. 2, end face 622, which is the surface of core 62 in the plate thickness direction, were to be brought into contact with outer ring 3 rather than the plate surface of core 62, it would be difficult to bring end face 622 into surface contact with outer ring 3 if end face 622 had burrs or if the angle of end face 622 had manufacturing or installation errors. In contrast, in this embodiment, the smooth plate surface of bent portion 621 of core 62 can be brought into surface contact with outer ring 3, making it easier to ensure electrical integrity between outer ring 3 and core 62.

[0027] As described above, in the rolling bearing 1 of this embodiment, the core 62 is in direct contact with the outer ring 3, ensuring electrical integrity between the outer ring 3 and the core 62. This reduces the electrical resistance of the conductive seal 6 compared to when the outer ring 3 and the core 62 are not in direct contact, improving conductivity and enhancing galvanic corrosion resistance. Reducing the electrical resistance of the conductive seal 6 is also effective in countering electromagnetic noise in the rolling bearing 1.

[0028] Furthermore, in the conductive seal 6, the ends of the conductive rubber 61 are held to the inner ring 2 and outer ring 3 by the restoring force of the conductive rubber 61. This allows the conductive seal 6 to absorb manufacturing errors in the inner ring 2 and outer ring 3 and fit snugly between the inner ring 2 and outer ring 3, sealing the internal space between the inner ring 2 and outer ring 3. Furthermore, the core metal 62 is located on the rolling element 4 side of the conductive rubber 61 and is not exposed to the outside of the rolling bearing 1, so there is no reduction in conductivity due to rust or the like.

[0029] In addition, in this embodiment, the smooth plate surface of the bent portion 621 of the core 62 contacts the outer ring 3, making it easier to ensure electrical integrity compared to when the end surface 622 of the core 62 contacts the outer ring 3.

[0030] In this embodiment, bent portion 621 of core metal 62 is bent 180°, resulting in a compact configuration. Therefore, even if the space inside groove 32 is small, a space-saving configuration can be realized in which bent portion 621 of core metal 62 contacts outer ring 3 while conductive rubber 61 seals the gap between inner ring 2 and outer ring 3.

[0031] Furthermore, in this embodiment, the ends of the conductive rubber 61 are positioned within the grooves 22, 32 of the inner ring 2 and the outer ring 3, and the bent portion 621 of the core metal 62 is brought into contact with the wall surface of the groove 32 of the outer ring 3. This makes it easy to maintain the position of the conductive seal 6 even if there is a shape error in the inner ring 2 or the outer ring 3, or if the inner ring 2 or the outer ring 3 expands and contracts due to heat.

[0032] However, the present invention is not limited to the above embodiment. For example, the conductive seal 6 may be provided on only one axial side of the rolling bearing 1. A normal seal or the like may be provided on the other side.

[0033] Furthermore, the bending angle of the bent portion 621 of the core 62 is not particularly limited. Fig. 3 is a cross-sectional view similar to that of Fig. 1 showing the configuration of a rolling bearing 1a, which is a modified example of the rolling bearing 1. As shown in the rolling bearing 1a in Fig. 3, the bent portion 621 of the core 62 of the conductive seal 6a may be L-shaped and bent at an angle of approximately 90°. This conductive seal 6a also achieves the same effect as above by having the plate surface of the core 62 directly contact the wall surface of the groove 32 in the outer ring 3 at the bent portion 621. In this case, however, the bent portion 621 will be configured to expand in a flange-like shape, and therefore, in terms of compactness, it is preferable to bend the bent portion 621 by 180° as described above.

[0034] Although the rolling elements 4 in this embodiment are spherical, they may also be cylindrical (rollers). In this case, the axial direction of the cylindrical element is aligned with the axial direction of the rolling bearing 1, and the cylindrical element is disposed between the inner ring 2 and the outer ring 3.

[0035] While the preferred embodiments of the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to these examples. It is clear that those skilled in the art can conceive of various modifications and alterations within the scope of the technical ideas disclosed in this application, and it is understood that these modifications and alterations also fall within the technical scope of the present invention. [Explanation of symbols]

[0036] 1, 1a, 100: Rolling bearings 2, 20: Inner circle 3, 30: outer ring 4, 40: rolling elements 5, 50: Retainer 6: Conductive seal 7, 70: Grease 60: Seal 61: Conductive rubber 62, 602: Core 601: Rubber 621: Bent part

Claims

1. a metal inner ring and an outer ring; a rolling element disposed between the inner ring and the outer ring; a conductive seal that seals an internal space between the inner ring and the outer ring; and the conductive seal includes a conductive rubber and a plate-shaped core metal; an end portion of the conductive rubber on the inner ring side and an end portion of the conductive rubber on the outer ring side are held by the inner ring and the outer ring by the restoring force of the conductive rubber, the core metal is attached to the rolling element side of the conductive rubber, A rolling bearing characterized in that, at a bent portion formed by bending an end portion of the core metal on the outer ring side, a plate surface of the core metal directly contacts the outer ring.

2. 2. The rolling bearing according to claim 1, wherein the bent portion is formed by bending an end of the core metal on the outer ring side by 180 degrees.

3. an end portion of the conductive rubber on the inner ring side and an end portion of the conductive rubber on the outer ring side are housed in grooves formed in the inner ring and the outer ring; 2. The rolling bearing according to claim 1, wherein a plate surface of the core metal at the bent portion contacts a wall surface of the groove formed in the outer ring.

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