Annular conductive member

Abstract

To reduce, in an annular conductive member that is fitted between an outer ring and an inner ring of a rolling bearing into which lubrication oil is supplied, the electrical resistance and stabilize contact for energization.SOLUTION: An annular conductive member 1 is fitted between an outer ring 11 and an inner ring 12 of a rolling bearing and has a flow passage F penetrating the inside and outside of the rolling bearing. The annular conductive member has an elastic body 4 made of rubber material, in which a conductive fiber 5 is integrated with a surface layer portion on one surface side of the elastic body, and a part of the conductive fiber 5 is exposed from the surface to form a conductive texture part A. An outer-diameter-side conductive texture portion, which is an outer-diameter-side portion of the conductive texture part A located at an outer peripheral portion of the elastic body 4, contacts the outer ring 11, and an inner-diameter-side conductive texture portion, which is an inner-diameter-side portion of the conductive texture part A located at an inner peripheral portion of the elastic body 4, contacts the inner ring 12.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an annular conductive member that prevents electrolytic corrosion of a rolling bearing. [Background technology]

[0002] For example, current may leak into the rotating shaft in motors and reduction gear units of electric vehicles, as well as inverter-driven motors other than those for electric vehicles. In such cases, the lubricating oil film in the rolling bearing supporting the rotating shaft may be broken, causing current to flow between the outer and inner rings, resulting in arc damage to the rolling surfaces of the rolling elements.

[0003] One structure for preventing electrolytic corrosion in such rolling bearings is to mount an annular conductive member between the outer ring and inner ring of the rolling bearing, into which lubricating oil is supplied (see, for example, Patent Documents 1 and 2).

[0004] The conductive ring 140, which is an annular conductive member in Patent Document 1, has connecting posts 142 made of a metal material, an inner ring side rubber member 154 made of conductive rubber, and an outer ring side rubber member 152 made of conductive resin. The connecting posts 142 extend radially between the outer ring 110 and the inner ring 120, and between adjacent connecting posts 142, there are formed through holes 148, which are flow paths that penetrate the inside and outside of the rolling bearing 100. A conductive lip 150 of the inner ring side rubber member 154 made of conductive rubber slides on the inner ring 120.

[0005] The conductive annular member 15, which is the annular conductive member in Patent Document 2, has a core member 41 made of a metal material and an elastic member 42 made of conductive rubber. The annular member 15 is formed with holes 51 or notches 52 that are flow paths that penetrate the inside and outside of the rolling bearing 10. An elastic lip portion 45 of the elastic member 42 made of conductive rubber slides on the inner ring 12. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2023-46521 [Patent Document 2] International Publication No. 2023 / 105618 Summary of the Invention [Problem to be solved by the invention]

[0007] A circular conductive member having a flow path that penetrates the inside and outside of a rolling bearing, as in Patent Documents 1 and 2, makes it possible to suppress an increase in stirring resistance when the bearing rotates in a rolling bearing to which lubricating oil is supplied.

[0008] However, the use of conductive rubber in the annular conductive member poses the problem of increased electrical resistance.Conductive rubber is made by dispersing conductive carbon black or metal powder in insulating rubber, and there is a limit to the amount of conductor that can be added in order to maintain the properties of the rubber, resulting in increased electrical resistance.

[0009] Furthermore, because electricity is passed through the conductive rubber lip while it is sliding against the inner ring of the rolling bearing, there is a problem of unstable contact for current flow. That is, because sliding the lip against the inner ring increases the sliding torque, a lubricant such as lubricating oil is used between the sliding surfaces to reduce the sliding torque. As a result, an oil film is formed on the sliding surfaces, creating a fluid lubrication state, reducing the contact area between the sliding surfaces of the inner ring and the lip, and therefore unstable contact for current flow.

[0010] The present invention aims to reduce electrical resistance and stabilize contact for electrical conduction in an annular conductive member mounted between the outer ring and inner ring of a rolling bearing into which lubricating oil is supplied. [Means for solving the problem]

[0011] A first aspect of the present invention provides an annular conductive member that is mounted between the outer ring and inner ring of a rolling bearing and has a flow path that penetrates the interior and exterior of the rolling bearing. The annular conductive member has an elastic body made of a rubber material, and conductive fibers are integrated into a surface layer on one surface of the elastic body, forming a conductive texture portion in which some of the conductive fibers are exposed from the surface. An outer diameter side conductive texture portion, which is the outer diameter side portion of the conductive texture portion located on the outer peripheral portion of the elastic body, contacts the outer ring, and an inner diameter side conductive texture portion, which is the inner diameter side portion of the conductive texture portion located on the inner peripheral portion of the elastic body, contacts the inner ring.

[0012] A second aspect of the present invention provides an annular conductive member that is mounted between the outer ring and inner ring of a rolling bearing and has a flow path that penetrates the interior and exterior of the rolling bearing. The annular conductive member includes a core having an engaging portion that engages with the outer ring, and an elastic body made of a rubber material joined to the core, and a surface layer on one surface of the elastic body is formed with conductive fibers integrated therein, and a conductive texture portion in which some of the conductive fibers are exposed from the surface. An outer diameter side conductive texture portion, which is the outer diameter side portion of the conductive texture portion located on the outer peripheral portion of the elastic body, contacts the core, and an inner diameter side conductive texture portion, which is the inner diameter side portion of the conductive texture portion located on the inner peripheral portion of the elastic body, contacts the inner ring.

[0013] In the annular conductive members according to the first and second aspects, the conductive fibers of the inner diameter side conductive texture portion that are exposed from the surface of the elastic body come into contact with the inner ring of the rolling bearing. Electrical current flows through the conductive fibers of the inner diameter side conductive texture portion while they are sliding on the inner ring, reducing electrical resistance. The conductive fibers sliding on the inner ring scrape through the oil film on the sliding surface, preventing the formation of an oil film on the sliding surface, as occurs when a conductive rubber lip slides on the inner ring. This stabilizes electrical contact between the conductive fibers and the inner ring.

[0014] A third aspect of the present invention is an annular conductive member according to the first or second aspect, wherein the inner diameter side conductive texture portion is a circumferentially discontinuous type that is discontinuous in the circumferential direction, or a circumferentially separated type that has radial cuts at predetermined intervals in the circumferential direction.

[0015] In the annular conductive member according to the third aspect, the inner diameter side conductive texture portion is circumferentially discontinuous or circumferentially separated, which reduces the reinforcing effect of the inner diameter side conductive texture portion on the elastic body, thereby reducing the tightening force applied to the inner ring with which the inner diameter side conductive texture portion comes into contact, and preventing an increase in rotational torque of the rolling bearing.

[0016] A fourth aspect of the present invention is an annular conductive member according to the first aspect, wherein the outer diameter side conductive texture portion is a circumferentially discontinuous type that is discontinuous in the circumferential direction, or a circumferentially separated type that has radial cuts at predetermined intervals in the circumferential direction.

[0017] According to the annular conductive member of the fourth aspect, even when the outer diameter side conductive texture portion is molded so as to be curved within a molding die, the sheet body of conductive fibers having a predetermined shape that becomes the outer diameter side conductive texture portion is easily deformed, thereby increasing the freedom of shape design. [Effects of the Invention]

[0018] As described above, the annular conductive member of the present invention is mounted between the outer ring and inner ring of a rolling bearing into which lubricating oil is supplied, and prevents electrolytic corrosion of the rolling bearing. This annular conductive member can reduce electrical resistance and stabilize contact for electrical conduction. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is an enlarged longitudinal sectional view of a main portion of a rolling bearing including an annular conductive member according to an embodiment of the present invention; [Figure 2]2 is an enlarged longitudinal cross-sectional view of a main portion showing the periphery of one annular conductive member in the rolling bearing of FIG. 1. FIG. [Figure 3] This is an oblique view showing the inner side in the width direction of an annular conductive member of an embodiment of the present invention, and shows an example of a conductive texture portion in which cloth-like conductive fibers are integrated into the surface layer portion of an elastic body. [Figure 4] 4 is an enlarged, partially cross-sectional perspective view showing a main part of the annular conductive member of FIG. 3. FIG. [Figure 5] 1 is a schematic diagram showing an enlarged cross section of a conductive texture portion formed by integrating cloth-like conductive fibers into the surface layer portion of an elastic body. [Figure 6] 5 is the same partial cross-sectional perspective view as FIG. 4, showing an example of a conductive texture portion formed by integrating nonwoven conductive fibers into the surface layer portion of an elastic body. [Figure 7] FIG. 10 is a perspective view showing a first modified example in which no holes are provided in the conductive fibers. [Figure 8] FIG. 10 is a perspective view showing a second modified example in which the outer diameter side conductive texture portion and the inner diameter side conductive texture portion are circumferentially discontinuous. [Figure 9] FIG. 10 is a perspective view showing a third modified example in which the outer diameter side conductive texture portion and the inner diameter side conductive texture portion are circumferentially separated types in which radial cuts are made at predetermined intervals in the circumferential direction. [Figure 10] FIG. 10 is an enlarged longitudinal cross-sectional view of a main portion showing a fourth modified example in which the inner diameter side conductive texture portion contacts the radial surface of the inner ring. [Figure 11] FIG. 10 is an enlarged longitudinal cross-sectional view of a main portion of a fifth modified example in which the core metal engages with the outer ring of the rolling bearing, the outer diameter side conductive texture portion contacts the core metal, and the inner diameter side conductive texture portion contacts the inner ring of the rolling bearing. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0021] In this specification, the direction parallel to the direction of the central axis of rotation of the rolling bearing is called the "width direction" (see, for example, arrow B in Fig. 1), and the direction perpendicular to the direction of the central axis of rotation is called the "radial direction" (see, for example, arrow R in Fig. 1). The "circumferential direction" (see, for example, arrow C in Fig. 3) is defined relative to the direction of the central axis of rotation.

[0022] In this specification, the width direction approaching the widthwise center of the rolling bearing (for example, symbol BC in Figure 1) is referred to as the "widthwise inner direction" (for example, see arrow BI in Figure 1), the width direction moving away from the widthwise center is referred to as the "widthwise outer direction" (for example, see arrow BO in Figure 1), the radial direction approaching the rotational center axis is referred to as the "radial direction inner direction" (for example, see arrow RI in Figure 1), and the radial direction moving away from the rotational center axis is referred to as the "radial direction outer direction" (for example, see arrow RO in Figure 1).

[0023] [Rolling bearings] 1 includes an outer ring 11, an inner ring 12, rolling elements 13, and a cage 14, as well as an annular conductive member 1 according to an embodiment of the present invention. The annular conductive member 1, which is located on the outer side in the width direction BO, is provided with a flow path F in the width direction B, allowing lubricating oil to be supplied from the outside to the inside of the rolling bearing 10. Because the rolling bearing 10 has flow path F that penetrates from the inside to the outside, the lubricating oil does not stagnate in the rolling bearing 10 when lubricating oil is supplied to the inside, and this makes it possible to suppress an increase in stirring resistance when the bearing rotates.

[0024] The rolling elements 13 roll between the raceway surfaces of the outer ring 11 and the inner ring 12. The cage 14 guides the rolling elements 13 at a predetermined interval and holds them rotatably. The outer peripheral portion G of the annular conductive member 1 engages with the engagement groove 11A of the outer ring 11. As a result, the annular conductive member 1 is attached to the outer ring 11 and is installed between the outer ring 11 and the inner ring 12.

[0025] [Annular conductive member] The annular conductive member 1 shown in Figure 2-4 has an annular core 3, an annular elastic body 4 made of a rubber material, and conductive fibers 5 that form the conductive texture portion A, which will be described later. The flow path F provided in the annular conductive member 1 is, for example, a through hole 2 formed by a hole 3B in the core 3, a hole 4B in the elastic body 4, and a hole H in the conductive texture portion A. The core 3 is used to improve the strength of the annular conductive member 1, and therefore may be eliminated depending on the strength required for the annular conductive member 1.

[0026] The rubber material is nitrile rubber (NBR), hydrogenated nitrile rubber (HNBR), acrylic rubber (ACM), silicone rubber (VQM), fluororubber (FKM), ethylene propylene diene rubber (EPDM), or the like.

[0027] [Conductive texture part] The surface layer on one side (inner side BI) in the thickness direction (width direction B) of the elastic body 4 has a conductive texture portion A integrated with conductive fibers 5. The conductive fibers 5 are carbon fibers or chemical fibers coated with a metal such as copper, nickel, or silver.

[0028] The conductive texture portion A shown in Figure 3-4 is formed by integrating cloth-like conductive fibers into the surface layer portion of the elastic body 4. That is, as shown in the schematic diagram of Figure 5, the conductive fibers 5 integrated into the surface layer portion D on one surface 4A side of the elastic body 4 are cloth-like and consist of a portion 6 protruding from the surface 4A of the elastic body 4 and a portion 7 embedded inside the elastic body 4. Therefore, the portion 6, which is a part of the conductive fibers 5, is exposed from the surface 4A of the elastic body 4.

[0029] As a result, as shown in Fig. 2, with the outer peripheral portion G of the annular conductive member 1 engaged in the engagement groove 11A of the outer ring 11, the conductive fibers 5 (portions 6) exposed from the surface 4A of the elastic body 4 of the outer diameter side conductive texture portion A1, which is the outer diameter side portion of the conductive texture portion A located on the outer peripheral portion 8 of the elastic body 4 (Fig. 3), come into contact with the outer ring 11. Furthermore, the conductive fibers 5 (portions 6) exposed from the surface 4A of the elastic body 4 of the inner diameter side conductive texture portion A2, which is the outer diameter side portion of the conductive texture portion A located on the inner peripheral portion 9 of the elastic body 4 (Fig. 3), come into contact with the outer peripheral surface 12A of the inner ring 12. Therefore, the conductive texture portion A provides electrical conductivity between the outer ring 11 and the inner ring 12.

[0030] 5, the structure in which the conductive fibers 5 are integrated into the surface layer D of the elastic body 4 greatly reduces the risk of the conductive fibers 5 peeling off from the elastic body 4. Furthermore, integrating the conductive fibers 5 into the surface layer D of the elastic body 4 and exposing a portion 6 of the conductive fibers 5 from the surface 4A of the elastic body 4 does not present manufacturing difficulties, and makes it easy to manufacture the annular conductive member 1, because the conductive fibers 5 are only located in the surface layer D of the elastic body 4, where it is relatively easy to control the position.

[0031] The conductive fibers 5 integrated into the surface layer D on one surface 4A side of the elastic body 4 in the conductive texture portion A are not limited to a cloth-like shape as shown in Figure 3-5, but may also be in the form of a nonwoven fabric as shown in Figure 6, and the conductive texture portion A may have a planar structure.

[0032] The annular conductive member 1 having such a conductive texture portion A can be easily manufactured by, for example, direct pressure molding as follows.

[0033] That is, first, an annular core metal 3 is placed on the lower mold of the molding die so that hole 3B fits around a shaft set up in a predetermined position in the lower mold. An annular pre-vulcanized rubber that will become elastic body 4 is placed on top of that, and then an annular sheet of cloth-like or nonwoven conductive fiber 5 is placed on top of that so that hole H fits around the shaft. Next, the upper mold of the molding die is closed and heated, and the pre-vulcanized rubber is vulcanized while pressure is applied to mold it. This allows the rubber to flow into the gaps between the conductive fibers 5 and mold it. After the rubber is vulcanized, the molded product is removed from the molding die to obtain an annular conductive member 1 having a conductive texture portion A as shown in Figures 3-4 or 6.

[0034] [Variations] The annular conductive member 1 of a first modified example shown in Figure 7 is an example in which the hole H of Figure 2-3 is not provided in the conductive fibers 5. The annular conductive member 1 of Figure 7 also has the hole 3B of the core 3 and the hole 4B of the elastic body 4 shown in Figure 2-3, and lubricating oil can pass through these holes and the sheet of conductive fibers 5, which is in the form of a cloth or nonwoven fabric. Therefore, the annular conductive member 1 has a flow path F that penetrates the inside and outside of the rolling bearing 10.

[0035] 7 has a flow path F that passes through the inside and outside of the rolling bearing 10, but the conductive texture portion A does not have a hole H (FIGS. 2-3) that communicates with the hole 3B of the core 3 and the hole 4B of the elastic body 4. Therefore, when lubricating oil flows in from the outside of the rolling bearing 10, the sheet of conductive fiber 5 located in the holes 3B and 4B filters out foreign matter such as metal powder, preventing early damage to the rolling bearing 10.

[0036] The second modified example shown in Fig. 8 differs from the annular conductive member 1 of Fig. 3 in the shape of the conductive texture portion A. That is, the conductive texture portion A in the annular conductive member 1 of Fig. 8 has the same shape as the conductive texture portion A in the annular conductive member 1 of Fig. 3, namely, the annular intermediate conductive texture portion A0, which is the intermediate portion of the conductive texture portion A in the radial direction R, but the shapes of the outer diameter side conductive texture portion A1 and the inner diameter side conductive texture portion A2 are different.

[0037] That is, the outer diameter side conductive texture portion A1 and the inner diameter side conductive texture portion A2 are not continuous in the circumferential direction C, but are circumferentially discontinuous I in that they are spaced apart in the circumferential direction C.

[0038] The third modified example shown in Figure 9 has the same shape as the annular conductive member 1 in Figure 3, but differs in that the outer diameter side conductive texture portion A1 and the inner diameter side conductive texture portion A2 have cuts E in the radial direction R.

[0039] That is, the outer diameter side conductive texture portion A1 and the inner diameter side conductive texture portion A2 are circumferentially separated type S in which cuts E in the radial direction R are made at predetermined intervals in the circumferential direction C.

[0040] By making the inner diameter side conductive texture portion A2 the circumferentially discontinuous type I or the circumferentially separated type S, the reinforcing effect of the inner diameter side conductive texture portion A2 on the elastic body 4 is suppressed. Therefore, the tightening force applied to the inner ring 12 with which the inner diameter side conductive texture portion A2 comes into contact can be reduced, and the rotational torque of the rolling bearing 10 does not increase.

[0041] By making the outer diameter side conductive texture portion A1 the circumferentially interrupted type I or the circumferentially separated type S, the sheet of conductive fiber of a predetermined shape that becomes the outer diameter side conductive texture portion A1 becomes easier to deform even when molding the outer diameter side conductive texture portion A1 so that it is curved within a molding die, thereby increasing the freedom of shape design.

[0042] The fourth modified example shown in Figure 10 shows an example in which the inner diameter side conductive texture portion A2 contacts the radial surface 12B of the inner ring 12, rather than the outer peripheral surface 12A of the inner ring 12 as shown in Figure 2.

[0043] 11 shows an example in which the outer diameter side conductive texture portion A1 contacts the core bar 3 rather than the outer ring 11 as shown in FIGS. 2 and 10. That is, the engagement portion 3A of the core bar 3 engages with the engagement groove 11A of the outer ring 11, the outer diameter side conductive texture portion A1 contacts the core bar 3, and the inner diameter side conductive texture portion A2 contacts the inner ring 12. Therefore, the core bar 3 and the conductive texture portion A provide electrical continuity between the outer ring 11 and the inner ring 12.

[0044] In an embodiment of the present invention, for example, as shown in Figures 2 and 10, the outer ring 11 and inner ring 12 are electrically connected by the conductive texture portion A. Alternatively, as shown in Figure 11, the outer ring 11 and inner ring 12 are electrically connected by the core bar 3 and the conductive texture portion A. Therefore, in a more preferred embodiment, the rubber material forming the elastic body 4 is not electrically conductive.

[0045] However, depending on the required specifications of the rolling bearing, conductive rubber may be used as the rubber material forming the elastic body 4. For example, if the required specifications require a large interference and there is concern that the inner diameter side conductive texture portion A2 that slides against the inner ring 12 will wear out in the future, it may be possible to use conductive rubber for the elastic body 4. In this case, after the inner diameter side conductive texture portion A2 wears out, the elastic body 4, which is made of conductive rubber, will come into contact with the inner ring 12. However, since the inner diameter side conductive texture portion A2 is located in close proximity to the elastic body 4 that contacts the inner ring 12, the distance over which electricity flows through the conductive rubber (the distance it wears) is short, and the effects of the present invention can be achieved.

[0046] [Major effects] The annular conductive member 1 according to the embodiment of the present invention as described above has a flow path F in the width direction B, so that when the annular conductive member 1 is attached to the outer width direction BO of the rolling bearing 10 (FIG. 1), it has a flow path F that penetrates from the inside to the outside of the rolling bearing 10. Therefore, it can be attached to and used in a rolling bearing 10 that is used in an environment where lubricating oil is supplied to the inside and a lubricating oil film is always present.

[0047] Furthermore, the conductive fibers 5 (portions 6) exposed from the surface 4A of the elastic body 4 in the inner diameter side conductive texture portion A2 come into contact with the inner ring 12 of the rolling bearing 10. Electricity flows through the conductive fibers 5 in the inner diameter side conductive texture portion A2 while they are sliding on the inner ring 12, reducing electrical resistance. The conductive fibers 5 sliding on the inner ring 12 scrape off the oil film on the sliding surface, preventing the formation of an oil film on the sliding surface as occurs when a conductive rubber lip slides on the inner ring 12. This stabilizes contact between the conductive fibers 5 and the inner ring 12 for electrical conduction.

[0048] The above description of the embodiments is given by way of example only and is not intended to be limiting, and various improvements and modifications can be made without departing from the scope of the present invention. [Explanation of symbols]

[0049] 1. Annular conductive member 2 through holes 3 Core 3A Engagement part 3B hole 4 Elastic Body 4A surface 4B hole 5. Conductive fibers 6. Parts that protrude from the surface of an elastic body 7 Parts embedded inside the elastic body 8 Outer periphery of elastic body 9 Inner circumference of elastic body 10. Rolling bearings 11 Outer ring 11A Engagement groove 12 Inner Circle 12A Outer surface 12B Radial surface 13 Rolling elements 14 Cage A Conductive texture part A0 Middle conductive textured part A1 Outer diameter conductive texture A2 Inner diameter conductive texture B Width direction BC Width center BI width direction inside BO Width direction outward C circumferential direction D Surface layer E Cut F flow path G outer periphery H hole I Circumferential intermittent type R Radial direction RI radially inward RO radially outward S Circumferentially separated type

Claims

1. An annular conductive member that is mounted between an outer ring and an inner ring of a rolling bearing and has a flow path that penetrates from the inside to the outside of the rolling bearing, It has an elastic body made of a rubber material, a surface layer portion on one surface side of the elastic body is integrated with conductive fibers, and a conductive texture portion is formed in which a part of the conductive fibers is exposed from the surface; an outer diameter side conductive texture portion, which is an outer diameter side portion of the conductive texture portion located on the outer periphery of the elastic body, contacts the outer ring; an inner diameter side conductive texture portion, which is an inner diameter side portion of the conductive texture portion located on the inner peripheral portion of the elastic body, contacts the inner ring; Annular conductive member.

2. An annular conductive member that is mounted between an outer ring and an inner ring of a rolling bearing and has a flow path that penetrates from the inside to the outside of the rolling bearing, a core having an engaging portion that engages with the outer ring, and an elastic body made of a rubber material and joined to the core, a surface layer portion on one surface side of the elastic body is integrated with conductive fibers, and a conductive texture portion is formed in which a part of the conductive fibers is exposed from the surface; an outer diameter side conductive texture portion, which is an outer diameter side portion of the conductive texture portion located on the outer periphery of the elastic body, contacts the core metal; an inner diameter side conductive texture portion, which is an inner diameter side portion of the conductive texture portion located on the inner peripheral portion of the elastic body, contacts the inner ring; Annular conductive member.

3. the inner diameter side conductive texture portion is a circumferentially discontinuous type that is discontinuous in the circumferential direction, or a circumferentially separated type that has radial cuts at predetermined intervals in the circumferential direction; The annular conductive member according to claim 1 or 2.

4. the outer diameter side conductive texture portion is a circumferentially discontinuous type that is discontinuous in the circumferential direction, or a circumferentially separated type that has radial cuts at predetermined intervals in the circumferential direction; The annular conductive member according to claim 1 .

Images