Annular conductive member, and method for manufacturing an annular conductive member

Abstract

The present invention provides an annular conductive member that offers good electrical conductivity between the outer and inner rings of a rolling bearing, stable conductivity, reduced sliding torque and wear compared to bearings with conductive rubber sliding contacts, and superior quietness and reduced generation of metal wear particles compared to bearings with metal-on-metal sliding contacts. [Solution] This is an annular conductive member 1 used in a rolling bearing 10 including an outer ring 11, an inner ring 12, and rolling elements 13. It is made of CFRP (carbon fiber reinforced polymer) which is isotropic in the direction along the annular surface, and has a locking portion 2 that engages with the outer ring 11 and a sliding portion 3 that slides on the inner ring 12. The carbon fibers contained in the CFRP are 30% by weight or more and 75% by weight or less, and the carbon fibers include some with a length of 5 mm or more.

Description

Technical Field

[0001] The present invention relates to an annular conductive member that prevents electrical corrosion of rolling bearings.

Background Art

[0002] For example, in motors and reduction gear units of electric vehicles, as well as inverter-driven motors other than those for electric vehicles, current may leak and flow to the rotating shaft. In that case, in the rolling bearing that supports the rotating shaft, current may flow between the outer ring and the inner ring breaking through the lubricating oil film, and the rolling surfaces of the rolling elements may be damaged by electric arcs.

[0003] As such annular conductive members for preventing electrical corrosion of rolling bearings, there are those configured with a main body portion composed of two annular seal plates formed of a conductive metal plate and an annular sliding portion (sliding contact portion) formed of conductive rubber (see, for example, Patent Document 1), those composed of an annular seal plate made of a press-formed product of a thin metal plate with excellent conductivity (see, for example, Patent Document 2), and the like.

[0004] On the other hand, in order to prevent the electrical corrosion, there is a configuration in which a crown-shaped cage is formed by injection molding using a conductive resin material instead of an annular conductive member, a rib in contact with the outer ring is formed on the radially outer surface of the pillar portions of the cage, and a rib in contact with the inner ring is formed on the radially inner surface of the pillar portions (see, for example, Patent Document 3).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0006] The conductive rubber used in Patent Document 1 is made by mixing a certain amount or more of carbon black, a finely powdered conductive substance, into rubber and kneading it, allowing electricity to flow through the dispersed carbon black. Conductivity can be improved by increasing the amount of carbon black added, but increasing the amount of carbon black impairs the excellent stretchability and elasticity that are inherent advantages of rubber, so there are limitations on the amount of carbon black that can be added. Therefore, in annular conductive members using conductive rubber like that in Patent Document 1, there are limitations on conductivity, and good electrical conductivity cannot be obtained between the outer ring and inner ring of a rolling bearing.

[0007] Furthermore, in annular conductive members like the one described in Patent Document 1, the sliding torque is large because the sliding part is made of conductive rubber. Generally, in sliding applications using rubber, a lubricant such as grease is interposed on the sliding surface to reduce torque. As a result, the lubrication becomes fluid lubrication, and the contact area between the conductive rubber and the sliding surface becomes smaller. Therefore, in annular conductive members using conductive rubber like the one described in Patent Document 1, the conductivity between the outer and inner rings of a rolling bearing is unstable.

[0008] The annular sealing plate used in Patent Document 2 is made of metal, and metals slide against metal. Therefore, an annular conductive member using a metal sealing plate like the one in Patent Document 2 produces loud running noise due to the rotation of the rolling bearing and generates metal wear particles.

[0009] Patent Document 3 uses a conductive resin. A conductive resin is made by adding conductive fibers to a resin to impart conductivity. Since longer conductive fibers make it easier to form conductive paths, it is preferable to increase the length of the conductive fibers added to the resin in order to improve conductivity.

[0010] A crown-shaped retainer of the required shape using a conductive resin, such as that described in Patent Document 3, needs to be manufactured by injection molding rather than direct pressure molding due to its complex shape.

[0011] In injection molding, since the resin raw material is supplied in pellet form, the size of the pellet material to which conductive fibers are added determines the maximum length of the conductive fibers, thus limiting the length of the conductive fibers. Furthermore, because the conductive fibers are oriented in the direction of the flow of the molten resin during injection molding, it becomes difficult to form a conductive network in which the conductive fibers are connected to each other. Therefore, in a crown-shaped cage of the required shape using conductive resin, such as in Patent Document 3, good conductivity may not be obtained between the outer ring and inner ring of the rolling bearing.

[0012] The present invention aims to provide an annular conductive member that provides good electrical conductivity between the outer and inner rings of a rolling bearing, stable conductivity, reduced sliding torque and wear compared to a bearing with conductive rubber sliding parts, and superior quietness and reduced generation of metal wear particles compared to a bearing with metal-on-metal sliding parts. [Means for solving the problem]

[0013] An annular conductive member according to a first aspect of the present invention is an annular conductive member used in a rolling bearing including an outer ring, an inner ring, and rolling elements, and is made of CFRP that is isotropic in the direction along the annular surface, having a locking portion that engages with the outer ring or the inner ring, and a sliding portion that slides on the inner ring or the outer ring. The carbon fibers contained in the CFRP are 30% by weight or more and 75% by weight or less, and the carbon fibers include those with a length of 5 mm or more.

[0014] According to the annular conductive member relating to the first aspect, it is made of integrally formed CFRP, and the sliding part slides on the inner or outer ring while the locking part is locked to the outer or inner ring. Furthermore, the CFRP contains 30% by weight or more of carbon fibers, and includes carbon fibers with a length of 5 mm or more. Therefore, good electrical conductivity is obtained between the outer and inner rings of the rolling bearing, and the conductivity is stable.

[0015] Furthermore, according to the annular conductive member relating to the first aspect, the sliding part made of CFRP slides on the sliding surface of the inner or outer ring of the rolling bearing. Because CFRP, which has excellent sliding properties, slides on the inner or outer ring, the sliding torque is reduced and wear is suppressed compared to those in which the sliding part is made of conductive rubber, and compared to those in which metals slide against metal, it is quieter and the generation of metal wear particles is suppressed.

[0016] Furthermore, according to the annular conductive member relating to the first aspect, it is made of CFRP that is isotropic in the direction along the annular surface, and can be made into a relatively simple annular shape with a nearly uniform and thin wall thickness. As a result, an annular nonwoven fabric body in which carbon fibers and synthetic resin fibers are intertwined can be manufactured by direct pressure press molding, in which heating and pressurizing are performed in a press molding die. Therefore, since there is no restriction on the length of the carbon fibers, it becomes easier to form conductive paths as long carbon fibers. Moreover, since it is molded from the nonwoven fabric body that is isotropic in the direction along the annular surface, it becomes easier to form a conductive network in which the carbon fibers are connected to each other.

[0017] An annular conductive member according to a second aspect of the present invention has an annular conductive member according to a first aspect, wherein the portion between the locking portion and the sliding portion has an inclined portion that moves away from the rolling element as it moves away from the sliding portion.

[0018] According to the annular conductive member relating to the second viewpoint, since it has an inclined portion that moves away from the rolling elements of the rolling bearing as it moves away from the sliding portion, a recess is formed on the rolling element side. Therefore, interference with the cage of the rolling bearing is easily avoided. Furthermore, by adjusting the inclination angle of the inclined portion, the reaction force of the sliding portion sliding on the sliding surface of the inner or outer ring (elastic restoring force of the annular conductive member) can be easily adjusted.

[0019] An annular conductive member according to a third aspect of the present invention is an annular conductive member according to a second aspect, wherein an annular core is joined to the side surface on the rolling element side between the locking portion and the sliding portion.

[0020] According to the annular conductive member according to the third aspect, the annular conductive member has an annular core metal joined to the side surface on the rolling element side of the rolling bearing between the locking portion and the sliding portion. Therefore, the thin-walled base body made of CFRP can be reinforced by the core metal, so that the rigidity and strength of the annular conductive member can be adjusted by the core metal.

[0021] The annular conductive member according to the fourth aspect of the present invention is the annular conductive member according to the first aspect, and has a plurality of notched portions spaced apart in the circumferential direction at the edge on the sliding portion side.

[0022] According to the annular conductive member according to the fourth aspect, the reaction force of the sliding portion (the elastic restoring force of the annular conductive member) can be adjusted by the notched portions, and when the rolling bearing is used in oil, the inside of the rolling bearing can be lubricated through the notched portions.

[0023] The annular conductive member according to the fifth aspect of the present invention is the annular conductive member according to the first aspect, and has a through hole that communicates the inside and the outside of the rolling bearing in the portion between the locking portion and the sliding portion.

[0024] According to the annular conductive member according to the fifth aspect, when the rolling bearing is used in oil, the inside of the rolling bearing can be lubricated through the through hole.

[0025] The method for manufacturing an annular conductive member according to the sixth aspect of the present invention is a method for manufacturing the annular conductive member according to any one of the first to fifth aspects, wherein the synthetic resin that is the binder of the CFRP is thermoplastic, and the method includes a step of forming an annular nonwoven fabric body in which the carbon fibers and the synthetic resin fibers are entangled, a step of heating a press mold for molding the nonwoven fabric body into the annular conductive member, a step of setting the nonwoven fabric body in the mold, a step of closing the mold, applying heat and pressure to melt the synthetic resin fibers and mold the nonwoven fabric body into the shape of the annular conductive member, a step of cooling the mold to cure the molded product, and a step of opening the mold and taking out the annular conductive member which is the molded product.

[0026] A method for manufacturing an annular conductive member according to the seventh aspect of the present invention is a method for manufacturing an annular conductive member according to any of the first to fifth aspects, wherein the synthetic resin that is the binder of the CFRP is thermosetting, and the method comprises the steps of: forming an annular nonwoven fabric body in which the carbon fibers and the synthetic resin fibers are intertwined; heating a press molding die for forming the nonwoven fabric body into the annular conductive member; setting the nonwoven fabric body in the die; closing the die, heating and pressurizing to melt the synthetic resin fibers and form the nonwoven fabric body into the shape of the annular conductive member, and then curing the molded product; and opening the die and removing the annular conductive member which is the molded product.

[0027] According to the method for manufacturing an annular conductive member relating to the sixth and seventh aspects, first, an annular nonwoven fabric is formed by intertwining fibers of thermoplastic synthetic resin or fibers of thermosetting synthetic resin with carbon fibers. Next, the annular and simple-shaped nonwoven fabric is heated and pressurized in a press molding die to form an annular conductive member made of CFRP having a locking portion that engages with the outer or inner ring of a rolling bearing and a sliding portion that slides on the inner or outer ring of the rolling bearing.

[0028] Therefore, in the direct pressure press molding process, since the annular nonwoven fabric is supplied to the press molding die, there are no restrictions on the length of the carbon fibers, making it easier to form conductive paths with long carbon fibers. Furthermore, because the molding is performed from the nonwoven fabric, which is isotropic in the direction along the annular surface, it becomes easier to form a conductive network in which the carbon fibers are connected to each other. [Effects of the Invention]

[0029] As described above, the annular conductive member according to the present invention provides good conductivity between the outer and inner rings of a rolling bearing, stable conductivity, reduced sliding torque and reduced wear compared to bearings where the sliding part is made of conductive rubber, and superior quietness and reduced generation of metal wear particles compared to bearings where metals slide against metal.

[0030] According to the annular conductive member and the method for manufacturing the annular conductive member of the present invention, the annular conductive member is made of CFRP that is isotropic in the direction along the annular surface, and can be made into a relatively simple annular shape with a substantially uniform and thin wall thickness. As a result, an annular nonwoven fabric body in which carbon fibers and synthetic resin fibers are intertwined can be manufactured by direct pressure press molding, in which heating and pressurizing are performed in a press molding die. Therefore, since there is no restriction on the length of the carbon fibers, it becomes easier to form conductive paths as long carbon fibers. Moreover, since it is molded from the nonwoven fabric body that is isotropic in the direction along the annular surface, it becomes easier to form a conductive network in which the carbon fibers are connected to each other. [Brief explanation of the drawing]

[0031] [Figure 1] This is a partial cross-sectional perspective view of a rolling bearing equipped with an annular conductive member according to an embodiment of the present invention. [Figure 2] This is an enlarged longitudinal cross-sectional view of the main part of the rolling bearing shown in Figure 1. [Figure 3] This is a schematic diagram of an annular conductive member that is isotropic in the direction along the annular surface, with (a) showing an example of "isotropy" and (b) and (c) showing examples of "pseudoisotropy". [Figure 4] The images show the appearance of an annular nonwoven fabric made of intertwined carbon fibers and synthetic resin fibers; (a) is a front view, and (b) is a side view. [Figure 5] This is a schematic cross-sectional view of a press molding die used to form the nonwoven fabric into an annular conductive member, showing the upper and lower dies in an open state. [Figure 6] This is a partial cross-sectional perspective view of a rolling bearing equipped with an annular conductive member according to the first modified example. [Figure 7] Figure 6 is an enlarged longitudinal cross-sectional view of the main part of the rolling bearing. [Figure 8] This is a partial cross-sectional perspective view of a rolling bearing equipped with an annular conductive member, representing a second modified example. [Figure 9] Figure 8 is an enlarged longitudinal cross-sectional view of the main part of the rolling bearing. [Figure 10] This is a perspective view of the annular conductive member of the second modified example. [Figure 11] This is a partial cross-sectional perspective view of a rolling bearing equipped with an annular conductive member, representing a third modified example. [Figure 12] Figure 11 is an enlarged longitudinal cross-sectional view of the main part of the rolling bearing. [Figure 13] This is a partial cross-sectional perspective view of a rolling bearing equipped with an annular conductive member, representing a fourth modified example. [Figure 14] Figure 13 is an enlarged longitudinal cross-sectional view of the main part of the rolling bearing. [Modes for carrying out the invention]

[0032] Embodiments of the present invention will be described below with reference to the drawings.

[0033] In this specification, the direction parallel to the rotational axis of a rolling bearing (for example, see reference numeral O in Figure 1) is referred to as the "width direction" (for example, see arrow B in Figures 1 and 2), and the direction perpendicular to the rotational axis is referred to as the "radial direction" (for example, see arrow R in Figure 2). The "circumferential direction" (for example, see arrow C in Figure 1) is defined with respect to the direction of the rotational axis.

[0034] In this specification, the width direction approaching the widthwise center of a rolling bearing (for example, the reference numeral BC in Figure 2) is referred to as the "inward width direction" (for example, see arrow BI in Figure 2), the width direction moving away from the widthwise center is referred to as the "outward width direction" (for example, see arrow BO in Figure 2), the radial direction approaching the rotational axis is referred to as the "inward radial direction" (for example, see arrow RI in Figure 2), and the radial direction moving away from the rotational axis is referred to as the "outward radial direction" (for example, see arrow RO in Figure 2).

[0035] [Rolling bearings] The rolling bearing 10 shown in Figure 1-2 comprises an outer ring 11, an inner ring 12, rolling elements 13, a cage 14, and an annular conductive member 1 according to an embodiment of the present invention. The rolling elements 13 roll between the raceway surface of the outer ring 11 and the raceway surface of the inner ring 12. The cage 14 guides the rolling elements 13 at predetermined intervals and holds them rotatably. The annular conductive member 1 is positioned outward BO in the width direction of the rolling elements 13 and the cage 14.

[0036] [Annular conductive material] The annular conductive member 1 shown in Figure 1-2 is made of CFRP (Carbon Fiber Reinforced Plastics) which is isotropic in the direction along the annular surface (in-plane direction), and has the function of electrically connecting the outer ring 11 and the inner ring 12.

[0037] Here, isotropy in the direction along the annular surface (in-plane direction) means that the performance or characteristics do not change in any direction within the in-plane direction, or that the performance or characteristics hardly change in any direction within the in-plane direction. The aforementioned isotropy includes not only "isotropy" as shown in Figure 3(a), but also "pseudoisotropy" as shown in Figures 3(b) and (b).

[0038] The carbon fiber content in the annular conductive member 1 is between 30% and 75% by weight. If the carbon fiber content in the annular conductive member 1 is less than 30% by weight, the amount of carbon fiber, which has excellent conductivity, decreases, resulting in reduced conductivity. If the content exceeds 75% by weight, the amount of synthetic resin, which acts as a binder, decreases, making it difficult to maintain the structure of the annular conductive member 1.

[0039] The carbon fibers contained in the annular conductive member 1 include those with a length of 5 mm or more. Since longer carbon fibers make it easier to form conductive paths, it is preferable to increase the length of the carbon fibers in order to improve conductivity.

[0040] As shown in Figure 2, the annular conductive member 1 is thin and has a substantially uniform thickness in the width direction B, and the thickness is, for example, about 0.3 to 0.6 mm.

[0041] As shown in Figure 2, the annular conductive member 1 has a locking portion 2 that engages with the outer ring 11 and a sliding portion 3 that slides on the inner ring 12. That is, with the locking portion 2 engaged with the locking groove 11A of the outer ring 11, the sliding portion 3 slides on the radial surface 12B, which is the sliding surface of the inner ring 12.

[0042] The annular conductive member 1 has an inner diameter inclined portion 4, which is an inclined portion IP, in the radially inward portion RI between the locking portion 2 and the sliding portion 3, and moves away from the rolling element 13 as it moves away from the sliding portion 3. That is, the inner diameter inclined portion 4 inclins outward in the width direction BO as it moves radially outward RO. Since the annular conductive member 1 is incorporated into the rolling bearing 10 with the inner diameter inclined portion 4 elastically deformed from a free state to outward in the width direction BO, it is pressed against the radial surface 12B of the inner ring 12 by the restoring force of the elastic deformation.

[0043] The annular conductive member 1 has an outer diameter inclined portion 5 that slopes radially outward RO of the inner diameter inclined portion 4, and then inward BI in the width direction as it moves radially outward RO. The longitudinal section (viewed from the circumferential direction C) of the annular conductive member 1 cut by a plane containing the rotational axis O of the rolling bearing 10 is mountain-shaped. The recess G formed by the mountain-shaped cross section faces the rolling elements 13 and the cage 14.

[0044] Because the inner diameter inclined portion 4 and the outer diameter inclined portion 5 form a recess G, interference with the cage 14 of the rolling bearing 10 is easily avoided. Furthermore, by adjusting the inclination angle of the inner diameter inclined portion 4, which is the inclined portion IP, the reaction force of the sliding portion 3 that slides on the radial surface 12B of the inner ring 12 (elastic restoring force of the annular conductive member 1) can be easily adjusted.

[0045] [Method for manufacturing an annular conductive member] The annular conductive member 1 is manufactured by direct pressure press molding, in which an annular nonwoven fabric A having the appearance shown in Figures 4(a) and (b) is heated and pressurized in the press molding die D shown in Figure 5.

[0046] [When the binder is a thermoplastic synthetic resin] (Process for forming nonwoven fabric) The annular conductive member 1 is manufactured from an annular nonwoven fabric A having the appearance shown in Figures 4(a) and (b). That is, for example, an annular nonwoven fabric A is formed by punching out a strip-shaped or sheet-shaped nonwoven fabric, which is made by intertwining carbon fibers and thermoplastic synthetic resin fibers, with a die-cutting tool. The carbon fiber content of the nonwoven fabric A is 30% by weight or more and 75% by weight or less, and the carbon fibers include those with a length of 5 mm or more.

[0047] Carbon fibers are PAN-based carbon fibers obtained by carbonizing a PAN precursor (polyacrylonitrile fiber), or pitch-based carbon fibers obtained by carbonizing a pitch precursor (pitch fiber obtained from coal tar or heavy petroleum components). Thermoplastic synthetic resins include PA (polyamide) 66, PPA (polyphthalamide), PBT (polybutylene terephthalate), polyphenylene sulfide (PPS), polyether ether ketone (PEEK), or polyamide-imide (PAI).

[0048] (The process of heating the press molding die) The press molding die D, which consists of an upper die 15 and a lower die 16 as shown in Figure 5, is heated to form a nonwoven fabric A into an annular conductive member 1.

[0049] (The process of setting the nonwoven fabric into a press molding die) With the press molding die D shown in Figure 5 open, the nonwoven fabric A is set inside the press molding die D so that the shaft portion 17 of the lower die 16 is inserted into the hole in the annular nonwoven fabric A shown in Figure 4.

[0050] (Process of press-forming into the shape of an annular conductive member) The press molding die D shown in Figure 5 is closed, and the nonwoven fabric A is heated and pressurized to melt the thermoplastic synthetic resin fibers, thereby molding the nonwoven fabric A into the shape of the annular conductive member 1.

[0051] (cooling process) The press molding die D is cooled to harden the molded product.

[0052] (Molded product removal process) The press molding die D is opened, and the molded product, the annular conductive member 1, is removed.

[0053] (Finishing process) A finishing process is performed on the molded annular conductive member 1 to remove any burrs, if necessary.

[0054] [When the binder is a thermosetting synthetic resin] The annular conductive member 1 is manufactured from an annular nonwoven fabric A having the appearance shown in Figures 4(a) and (b). That is, for example, an annular nonwoven fabric A is formed by punching out a strip-shaped or sheet-shaped nonwoven fabric, which is made by intertwining carbon fibers and thermosetting synthetic resin fibers, with a die-cutting tool. The carbon fiber content of the nonwoven fabric A is 30% by weight or more and 75% by weight or less, and the carbon fibers include those with a length of 5 mm or more.

[0055] The carbon fiber is either the PAN-based carbon fiber or the pitch-based carbon fiber. The thermosetting synthetic resin is a phenolic resin (PF), epoxy resin (EP), or polyimide resin (PI), etc.

[0056] (The process of heating the press molding die) The press molding die D, which consists of an upper die 15 and a lower die 16 as shown in Figure 5, is heated to form a nonwoven fabric A into an annular conductive member 1.

[0057] (The process of setting the nonwoven fabric into a press molding die) With the press molding die D shown in Figure 5 open, the nonwoven fabric A is set inside the press molding die D so that the shaft portion 17 of the lower die 16 is inserted into the hole in the annular nonwoven fabric A shown in Figure 4.

[0058] (Process of press-forming into the shape of an annular conductive member) The press molding die D shown in Figure 5 is closed, the nonwoven fabric A is heated and pressurized to melt the thermoplastic synthetic resin fibers, and the nonwoven fabric A is molded into the shape of the annular conductive member 1, after which the molded product is cured.

[0059] (Molded product removal process) The press molding die D is opened, and the molded product, the annular conductive member 1, is removed.

[0060] (Finishing process) A finishing process is performed on the molded annular conductive member 1 to remove any burrs, if necessary.

[0061] [First modification of an annular conductive member] The annular conductive member 1 of the first modified example shown in Figure 6-7 has an annular core metal 7 joined between the locking portion 2 and the sliding portion 3. The core metal 7 is joined to the surface (the surface inward BI in the width direction) of the intermediate portion 6 between the inner diameter side inclined portion 4 and the outer diameter side inclined portion 5 that is on the rolling element 13 side. Therefore, the CFRP base, which is formed with a thin wall thickness, can be reinforced by the core metal 7, and the rigidity and strength of the annular conductive member 1 can be adjusted by the core metal 7.

[0062] The shape of the press molding die D shown in Figure 5 is set to the required shape that allows the core metal 7 to be placed inside the press molding die D. With the core metal 7 placed inside the press molding die D, the annular nonwoven fabric A, which has the appearance shown in Figures 4(a) and (b), is set inside the press molding die D and directly press-molded into the shape of the annular conductive member 1 shown in Figure 6-7.

[0063] In the first modified annular conductive member 1 shown in Figure 6-7, the longitudinal section (viewed from the circumferential direction C) obtained by cutting the annular conductive member 1 through a plane containing the rotational axis O of the rolling bearing 10 is an isosceles trapezoidal shape. The recess G formed by the isosceles trapezoidal cross section faces the rolling elements 13 and the cage 14. Since the recess G is formed by the inner diameter side inclined portion 4, the intermediate portion 6, and the outer diameter side inclined portion 5, interference with the cage 14 of the rolling bearing 10 is easily avoided.

[0064] [Second variation of the annular conductive member] The annular conductive member 1 of the second modified example shown in Figure 8-10 has a plurality of notches 8 spaced apart in the circumferential direction C at the end edge E on the sliding portion 3 side. The notches 8 are formed at, for example, eight locations, equally spaced in the circumferential direction C.

[0065] By providing a notch 8 in the annular conductive member 1, the reaction force of the sliding part 3 (the elastic restoring force of the annular conductive member 1) can be adjusted, and when the rolling bearing 10 is used in oil, the inside of the rolling bearing 10 can be lubricated through the notch 8.

[0066] [Third Modification of the Annular Conductive Member] The annular conductive member 1 of the third modified example shown in Figure 11-12 has through holes 9 in the portion between the locking portion 2 and the sliding portion 3 that connect the inside and outside of the rolling bearing 10. The through holes 9 are formed, for example, at four locations in the inner diameter inclined portion 4, with equal divisions C in the circumferential direction.

[0067] By providing a through-hole 9 in the annular conductive member 1, the inside of the rolling bearing 10 can be lubricated through the through-hole 9 when the rolling bearing 10 is used in oil.

[0068] [Fourth modification of the annular conductive member] The annular conductive member 1 of the fourth modified example shown in Figure 13-14 has a locking portion 2 that engages with the inner ring 12 and a sliding portion 3 that slides on the outer ring 11. That is, with the locking portion 2 engaged with the locking groove 12A of the inner ring 12, the annular conductive member 1 has the sliding portion 3 sliding on the radial surface 11B, which is the sliding surface of the outer ring 11.

[0069] The annular conductive member 1 has an outer diameter inclined portion 5, which is an inclined portion IP, in the radially outer RO portion between the locking portion 2 and the sliding portion 3, and moves away from the rolling element 13 as it moves away from the sliding portion 3. That is, the outer diameter inclined portion 5 inclins outward in the width direction BO as it moves radially outward RI. Since the annular conductive member 1 is incorporated into the rolling bearing 10 with the outer diameter inclined portion 5 elastically deformed from a free state to outward in the width direction BO, it is pressed against the radial surface 11B of the outer ring 11 by the restoring force of the elastic deformation.

[0070] The annular conductive member 1 has an inner diameter inclined portion 4 that slopes radially inward RI of the outer diameter inclined portion 5, and then slopes radially inward BI in the width direction as it moves radially inward RI. The longitudinal section (viewed from the circumferential direction C) of the annular conductive member 1 cut by a plane containing the rotational axis O of the rolling bearing 10 is mountain-shaped. The recess G formed by the mountain-shaped cross section faces the rolling elements 13 and the cage 14.

[0071] Because a recess G is formed by the outer diameter inclined portion 5 and the inner diameter inclined portion 4, interference with the cage 14 of the rolling bearing 10 can be easily avoided. Furthermore, by adjusting the inclination angle of the outer diameter inclined portion 5, which is the inclined portion IP, the reaction force of the sliding portion 3 that slides on the radial surface 11B of the outer ring 11 (elastic restoring force of the annular conductive member 1) can be easily adjusted.

[0072] [Effects and Effects] According to the annular conductive member 1 of the present invention, it is made of integrally formed CFRP, and the sliding part 3 slides on the inner ring 12 or outer ring 11 while the locking part 2 is locked to the outer ring 11 or inner ring 12. Furthermore, the CFRP has a carbon fiber content of 30% by weight or more, and includes carbon fibers with a length of 5 mm or more. Therefore, good conductivity is obtained between the outer ring 11 and the inner ring 12 of the rolling bearing 10, and the conductivity is stable.

[0073] Furthermore, according to the annular conductive member 1 of the embodiment of the present invention, the sliding part 3 made of CFRP slides on the sliding surface of the inner ring 12 or outer ring 11 of the rolling bearing 10. Because CFRP, which has excellent sliding properties, slides on the inner ring 12 or outer ring 11, the sliding torque is reduced and wear is suppressed compared to cases where the sliding part is made of conductive rubber, and the noise level is lower and the generation of metal wear particles is suppressed compared to cases where metals slide against metal.

[0074] Furthermore, according to the annular conductive member 1 of the present invention, it is made of CFRP that is isotropic in the direction along the annular surface, and can be made into a relatively simple annular shape with a substantially uniform and thin wall thickness. As a result, an annular nonwoven fabric A, in which carbon fibers and synthetic resin fibers are intertwined, can be manufactured by direct pressure press molding in which it is heated and pressurized in a press molding die D.

[0075] Furthermore, according to the annular conductive member 1 of the embodiment of the present invention, since it is made of CFRP, it has high specific strength and specific stiffness and low density, so the reinforcing effect of the synthetic resin binder is high and a significant reduction in weight can be achieved. Moreover, since it contains long carbon fibers, even if damage such as cracking occurs in the synthetic resin binder, the structure can be maintained by the carbon fibers.

[0076] According to an embodiment of the present invention, an annular conductive member 1 and a method for manufacturing the annular conductive member 1 are first formed by intertwining fibers of thermoplastic synthetic resin or thermosetting synthetic resin with carbon fibers. Next, the annular and simple-shaped nonwoven fabric A is heated and pressurized in a press molding die D to form an annular conductive member 1 made of CFRP having a locking portion 2 that engages with the outer ring 11 or inner ring 12 of the rolling bearing 10 and a sliding portion 3 that slides on the inner ring 12 or outer ring 11 of the rolling bearing 10.

[0077] Therefore, in the direct pressure press molding described above, since the material supplied to the press molding die D is an annular nonwoven fabric A, there are no restrictions on the length of the carbon fibers, making it easier to form conductive paths with long carbon fibers. Furthermore, because the molding is performed from a nonwoven fabric A that is isotropic in the direction along the annular surface, it becomes easier to form a conductive network in which the carbon fibers are connected to each other.

[0078] All embodiments described above are illustrative and not limiting. Various improvements and modifications can be made without departing from the scope of the present invention. [Explanation of Symbols]

[0079] 1. Annular conductive member 2. Locking part 3. Sliding part 4. Inclined part on the inner diameter side 5 Outer diameter side inclined part 6 Middle part 7. Core metal 8. Notch 9 through holes 10 rolling bearings 11 Outer ring 11A Locking groove 11B Radial surface (sliding surface) 12 Inner ring 12A Locking groove 12B Radial surface (sliding surface) 13 Rolling element 14 Cage 15 Upper mold 16 Lower mold 17. Shaft section A Nonwoven fabric B Width direction BC Width center BI Width inward BO Width direction outward C Circumferential direction D Press forming die E Edge G Recess IP Inclined part O: Rotational axis R: Radial direction RI radially inward RO radially outward

Claims

1. An annular conductive member used in a rolling bearing including an outer ring, an inner ring, and rolling elements, It is made of CFRP that is isotropic in the direction along the annular surface, having a locking portion that engages with the outer ring or the inner ring, and a sliding portion that slides on the inner ring or the outer ring. The carbon fibers contained in the CFRP are 30% by weight or more and 75% by weight or less. The carbon fibers include those with a length of 5 mm or more. Annular conductive member.

2. The portion between the locking portion and the sliding portion has an inclined portion that moves away from the rolling element as it moves away from the sliding portion, The annular conductive member according to claim 1.

3. An annular core is joined to the side surface on the rolling element side between the locking portion and the sliding portion, The annular conductive member according to claim 2.

4. The edge on the sliding side has a plurality of notches spaced apart in the circumferential direction, The annular conductive member according to claim 1.

5. The portion between the locking portion and the sliding portion has a through hole that connects the inside and outside of the rolling bearing. The annular conductive member according to claim 1.

6. A method for manufacturing an annular conductive member according to any one of claims 1 to 5, The synthetic resin that serves as the binder for the aforementioned CFRP is thermoplastic. A step of forming an annular nonwoven fabric by intertwining the carbon fibers and the synthetic resin fibers, A step of heating a press molding die for forming the nonwoven fabric into the annular conductive member, A step of setting the nonwoven fabric in the mold, The process involves closing the mold, heating and pressurizing it to melt the synthetic resin fibers and form the nonwoven fabric into the shape of the annular conductive member, A step of cooling the mold to harden the molded product, The process of opening the mold and removing the annular conductive member which is the molded product, Having, A method for manufacturing an annular conductive member.

7. A method for manufacturing an annular conductive member according to any one of claims 1 to 5, The synthetic resin that serves as the binder for the aforementioned CFRP is thermosetting. A step of forming an annular nonwoven fabric by intertwining the carbon fibers and the synthetic resin fibers, A step of heating a press molding die for forming the nonwoven fabric into the annular conductive member, A step of setting the nonwoven fabric in the mold, The process involves closing the mold, heating and pressurizing to melt the synthetic resin fibers and form the nonwoven fabric into the shape of the annular conductive member, and then curing the molded product. The process of opening the mold and removing the annular conductive member which is the molded product, Having, A method for manufacturing an annular conductive member.

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