Shaft grounding member and rolling bearing unit for rolling bearings

Abstract

The present invention provides a shaft grounding member for a rolling bearing, and a rolling bearing unit equipped with the shaft grounding member, which can be securely fixed to the rolling bearing unit, thereby suppressing a decrease in conductivity and preventing the occurrence of rotational creep of the fixed ring. [Solution] The shaft grounding member for the rolling bearing comprises a spring plate composed of an annular portion and one or more elastic portions extending radially from the annular portion, a soft conductive member mounted on the surface of the elastic portion facing the rotating wheel, and a flexible member mounted on the side surface of the annular portion facing the spacer, and the soft conductive member is capable of contacting the side surface of the rotating wheel. The rolling bearing unit also includes the shaft grounding member.

Description

Technical Field

[0001] The present invention relates to a shaft grounding member for a rolling bearing, which is mounted to suppress the occurrence of electric corrosion or electromagnetic noise in the rolling bearing of a rolling bearing unit, and to a rolling bearing unit equipped with the shaft grounding member for a rolling bearing.

Background Art

[0002] In recent years, electric vehicles that drive wheels by disposing an electric motor as a drive source inside or near the wheels have been increasingly put into practical use. Such an electric motor is generally called an in-wheel motor. The structure of a general in-wheel motor is a so-called inner rotor type motor, in which a stator is fixed to a motor housing, and a rotor is disposed with a radial gap on the inner diameter side of the stator. In addition, as a drive system for in-wheel motors, brushless DC motors driven by inverters are widely used in consideration of motor performance and control performance.

[0003] In the inverter-driven system, a potential difference is generated between the stator and the rotor due to parasitic capacitance between the stator and the rotor. This potential difference generates so-called shaft voltage and shaft current. When the shaft current passes through the rolling bearing that supports the rotor, a phenomenon called "electric corrosion" that damages the rolling bearing occurs. Specifically, current flows locally at the contact portion between the raceway surfaces of the outer ring and inner ring of the rolling bearing and the rolling surfaces of the rolling elements, causing melting and other irregularities on the raceway surfaces or rolling surfaces. This roughens the raceway surfaces and rolling surfaces, which not only causes noise and vibration, but also affects the service life of the bearing if excessive electric corrosion occurs.

[0004] In order to prevent electric corrosion of rolling bearings, conductive members have also been interposed. For example, Patent Documents 1 and 2 propose a structure consisting of a contact member for electrical conduction with the rotor of a motor, an elastic member for pressing the contact member toward the rotor side, and a storage part that accommodates the contact member and the elastic member, wherein the storage part is provided in the motor housing and is electrically conducted with the motor stator via the motor housing.

[0005] Furthermore, Patent Document 3 proposes an earthing device in which the tip of a broom-shaped conductive fiber is brought into contact with the outer surface of a rotating shaft.

[0006] Furthermore, Patent Document 4 proposes an electrolytic corrosion prevention device in which an annular seat portion that contacts the end face of the bearing outer ring is bent into a wave washer shape, and an elastic conductor having a contact piece that extends from the inside of the annular seat portion and contacts the vicinity of the center of the end face of the rotating shaft is used, and the annular seat portion is superimposed on the end face of the bearing outer ring fitted into the bearing housing, and the contact piece is in contact with the vicinity of the center of the end face of the rotating shaft fitted into the bearing inner ring, and the surface of the annular seat portion is pressed by the lid-shaped wall of the bearing housing to make it electrically conductive.

[0007] Furthermore, Patent Document 5 proposes housing a rod-shaped conductive brush in a support hole provided in one of the two raceway rings, and using an elastic member to bias the tip of the conductive brush toward the other raceway ring, thereby electrically connecting the two raceway rings.

[0008] Patent Document 6 proposes providing a carbon filament shaft grounding brush with its tip in contact with the extension shaft to ground and remove the shaft voltage generated on the shaft, thereby preventing electrolytic corrosion that occurs in the bearing.

[0009] Incidentally, bearings require measures to counter electromagnetic noise generated by electromagnetic interference, and various devices have been proposed to suppress the generation of electromagnetic noise. For example, Patent Document 7 proposes housing a conductive rod-shaped carbon brush between an inner ring and a metal ring, and biasing the tip of the carbon brush, which is attached to the metal ring by a spring, against the inner ring to bring it into sliding contact. This imparts conductive properties to the conductive bearing and also allows the current flowing through the conductive bearing to flow out of the system via the metal ring and brush, thereby eliminating electromagnetic noise.

[0010] Patent Document 8 proposes a conductive device that can dissipate electromagnetic noise by suppressing the formation of an oil film between a conductive rubber lip and a metal housing attached to a rotating shaft using centrifugal force, or by controlling the thickness of the oil film. By suppressing the formation of the oil film or reducing its thickness, the electrical resistance of the oil film is reduced, making it possible to dissipate electromagnetic noise from the rotating shaft to the housing.

[0011] Patent Document 9 proposes improving electromagnetic noise prevention and electrolytic corrosion prevention by ensuring a path for electric charge by having conductive rolling elements roll between the outer and inner rings while the oil film is broken, thereby significantly reducing the impedance between the outer and inner rings, or the entire bearing.

[0012] Patent Document 10 proposes an electromagnetic noise suppression device that electrically connects the metal case of the electric motor and the rotating shaft inside the electric motor using conductive means such as a sliding contact member, thereby diverting electromagnetic noise induced on the rotating shaft to a metal electric motor housing grounded to the vehicle body. [Prior art documents] [Patent Documents]

[0013] [Patent Document 1] Japanese Patent Publication No. 2011-135720 [Patent Document 2] Japanese Patent Publication No. 2011-135722 [Patent Document 3] Japanese Patent Publication No. 2020-127257 [Patent Document 4] Japanese Patent Publication No. 2002-146568 [Patent Document 5] Japanese Utility Model Publication No. 4-8820 [Patent Document 6] Japanese Patent Publication No. 2017-060401 [Patent Document 7] Japanese Patent Publication No. 2024-130948 [Patent Document 8] Japanese Patent Publication No. 2023-018214 [Patent Document 9] Japanese Patent Publication No. 2022-139252 [Patent Document 10] Japanese Patent Publication No. 2000-244180 [Overview of the project] [Problems that the invention aims to solve]

[0014] However, in all the technologies described in the patent documents, wear particles generated from the conductive member may contaminate the lubricant or grease composition sealed inside for lubrication, potentially damaging the rolling surface or contact surface. Furthermore, the conductive member may damage the mating material, generating wear particles from that material as well.

[0015] To explain in more detail, in Patent Documents 1 and 2, the contact body, elastic body, and housing are made of metal, and metal powder is generated when these come into contact with each other due to the vibration of the motor. In addition, the contact body, elastic body, and housing need to be installed in the motor housing, and space is required for this.

[0016] Furthermore, in Patent Document 3, the tip of the broom-shaped conductive fiber is brought into contact with the outer surface of the rotating shaft. However, in order to increase the contact area between the tip of the broom-shaped conductive fiber and the rotating shaft compared to simply bringing them into contact, the broom-shaped conductive fiber is brought into contact with the outer surface of the rotating shaft in a bent state. That is, the tip of the broom-shaped conductive fiber is in contact with the outer surface of the rotating shaft with a certain degree of strong pressure, and wear particles are generated. At the same time, the outer surface of the rotating shaft, which is the mating material of the broom-shaped conductive fiber, is also damaged.

[0017] Furthermore, in Patent Document 4, both the elastic conductor and the rotating shaft are made of metal, and metal powder is generated when the two come into contact. At the same time, the end face of the rotating shaft, which is the mating material of the elastic conductor, is damaged.

[0018] Further, in Patent Document 5, since the tip end of the rod-shaped conductive brush is in contact with the other race ring in a biased state, abrasion powder of the conductive brush is generated. At the same time, the other race ring, which is the counterpart material of the conductive brush, is also damaged. Furthermore, it is necessary to form a support hole for accommodating the conductive brush and the elastic member in the race ring, which applies a large load to the race ring.

[0019] In Patent Document 6, since the tip end portion of the shaft grounding brush made of carbon filament is provided so as to abut against the extension shaft, abrasion powder of the shaft grounding brush is generated. At the same time, the extension shaft, which is the counterpart material of the shaft grounding brush, is also damaged.

[0020] Furthermore, in the bearings disclosed in Patent Documents 1 to 9, frictional heat may be generated due to sliding contact between the conductive member and the counterpart material during use, which reduces the durability of the bearing. In addition, along with the higher performance of motors in recent years, the peripheral speed of rotating members has also increased, so further suppression of temperature rise is required.

[0021] Further, in Patent Document 10, although a wear-resistant member is selected as the sliding contact member, the effect of reducing wear is not sufficient. Furthermore, depending on the fixing method of the sliding contact member, vibration may also occur in the sliding contact member along with the rotation of the bearing member, and abnormal wear may occur in the sliding contact member or the fixing member that fixes the sliding contact member. This abnormal wear makes it difficult to ensure stable conductivity.

[0022] In addition, in a rolling bearing, as the rotating member rotates, a slight gap is generated on the fitting surface between the fixed ring and the fixed member, which may cause creep. When creep occurs in the fixed ring, it may cause vibration and abnormal wear of the bearing, thereby degrading the function of the bearing. Particularly, when a different material from the bearing material such as aluminum is used for the housing or the rotating shaft as the fixed member to which the fixed ring is fitted, loosening of the fitting between the fixed ring and the fixed member is likely to occur due to temperature change, and creep is likely to occur.

[0023] Therefore, the present invention aims to provide a shaft grounding member for a rolling bearing, which is installed to suppress the occurrence of electrolytic corrosion or electromagnetic noise in a rolling bearing, and a rolling bearing unit equipped with the shaft grounding member, which can be securely fixed to the rolling bearing unit, thereby suppressing a decrease in conductivity and preventing the occurrence of rotational creep of the fixed ring. [Means for solving the problem]

[0024] The above objectives of the present invention are achieved by the configurations described below [1] to

[14] .

[0025] [1] A shaft grounding member to be mounted on a rolling bearing unit which has a rolling bearing in which one raceway is a fixed wheel and the other raceway is a rotating wheel, A spring plate made of a thin sheet of conductive material is composed of an annular portion and at least one elastic portion that extends radially continuously from the annular portion, In the elastic portion, a soft conductive member is mounted on the surface facing the rotating wheel or the rotating member into which the rotating wheel is fitted, A flexible member attached to the side surface of the annular portion, In addition to being equipped, The soft conductive member is capable of contacting at least a portion of the surface of the rotating wheel, or at least a portion of the surface of the rotating member. A shaft grounding member for rolling bearings, characterized by the above.

[0026] [2] The shaft grounding member for rolling bearings according to [1], characterized in that the flexible member is conductive.

[0027] [3] The flexible member is attached to both sides of the annular portion, and the flexible member attached to at least one of the two sides is electrically conductive, as described in [1] or [2].

[0028] [4] The shaft grounding member for a rolling bearing according to any one of [1] to [3], characterized in that the flexible member is composed of at least one selected from a soft porous body selected from nonwoven fabric, woven fabric and sponge, and a resin impregnated soft porous body.

[0029] [5] The shaft grounding member for a rolling bearing according to any one of [1] to [4], characterized in that the flexible member and the soft conductive member are a single member attached to the same side surface of the annular portion and the elastic portion.

[0030] [6] The shaft grounding member for a rolling bearing according to any one of [1] to [5], characterized in that the annular portion is electrically connected to the fixed ring or the fixed member to which the fixed ring is fixed.

[0031] [7] The spring plate is composed of the annular portion and a plurality of elastic portions that extend radially in a continuous manner from the annular portion, The rolling bearing shaft grounding member according to any one of [1] to [6], characterized in that the plurality of elastic parts are bent toward the rotating ring.

[0032] [8] The spring plate is composed of the annular portion and a plurality of elastic portions that extend radially in a continuous manner from the annular portion, The rolling bearing shaft grounding member according to any one of [1] to [6], characterized in that the plurality of elastic portions are formed flush with the annular portion.

[0033] [9] A rolling bearing of the inner ring rotation type, in which the outer ring is a fixed ring and the inner ring is a rotating ring, A rolling bearing unit equipped with a rolling bearing shaft grounding member described in any one of [1] to [8], The outer ring is fixed to the housing, and the inner ring has a shaft fitted into it. A rolling bearing unit characterized in that the annular portion is held between the outer ring and a retaining portion provided integrally with or separately from the housing.

[0034]

[10] A rolling bearing of the outer ring rotation type, in which the inner ring is a fixed ring and the outer ring is a rotating ring, A rolling bearing unit equipped with a rolling bearing shaft grounding member described in any one of [1] to [8], The outer ring is fitted onto a rotating member, and the inner ring is fixed to a stationary member. A rolling bearing unit characterized in that the annular portion is held between the inner ring and a retaining portion provided integrally with or separately from the shaft.

[0035]

[11] The rolling bearing is of the inner ring rotation type, wherein the fixed ring is an outer ring fixed to the housing, and the rotating ring is an inner ring into which a shaft directly connected to the motor is fitted. The spring plate is composed of the annular portion and the elastic portion which extends from the inner circumferential end of the annular portion to the center of the annular portion, The soft conductive member is mounted on the side of the elastic portion facing the shaft and is capable of contacting the end face or side surface of the shaft. A shaft grounding member for a rolling bearing according to any one of [1] to [8], characterized in that...

[0036]

[12] The shaft grounding member for rolling bearings according to

[11] , characterized in that the elastic portion of the spring plate is bent in the middle.

[0037]

[13] The shaft grounding member for a rolling bearing according to

[11] , characterized in that the elastic portion of the spring plate is formed flush with the annular portion.

[0038]

[14] A rolling bearing of the inner ring rotation type, in which the outer ring is a fixed ring and the inner ring is a rotating ring, A rolling bearing unit equipped with a rolling bearing shaft grounding member described in any one of

[11] to

[13] , The outer ring is fixed to the housing, and the inner ring has a shaft fitted into it. A rolling bearing unit characterized in that the annular portion is held between the outer ring and a retaining portion provided integrally with or separately from the housing. [Effects of the Invention]

[0039] In this invention, the shaft grounding member has a flexible member, and the shaft grounding member is fixed to the rolling bearing unit in a compressed state, and the shaft grounding member can be securely fixed by the force of the flexible member trying to restore itself. Furthermore, even if loosening occurs in the fit between the bearing unit and the shaft grounding member, the fixing can be maintained by the force of the flexible member trying to restore itself. Therefore, it is possible to suppress the decrease in conductivity due to loosening of the shaft grounding member's fixing or the occurrence of vibration, reduce the shaft voltage, which is the potential difference between the rotating member and the fixed member, prevent electrolytic corrosion of the rolling bearing, and allow electromagnetic noise to escape through the space between the rotating member and the fixed member.

[0040] Furthermore, because the flexible member attempts to restore itself, pressure is constantly applied to the point where the shaft contact member is fixed. This ensures that the fixing member and the bearing's fixed ring are securely fixed, thereby suppressing rotational creep of the fixed ring.

[0041] Furthermore, the shaft grounding member of the present invention has a soft conductive member attached to the elastic portion of a spring plate, which then contacts at least a portion of the surface of the rotating wheel or rotating member. The biasing force exerted by the spring plate on the rotating wheel or rotating member by the soft conductive member is not very strong, and wear particles are less likely to be generated. Moreover, because the soft conductive member is made of a soft material, it causes less damage to the mating material, the rotating wheel.

[0042] Furthermore, the shaft grounding member of the present invention is highly versatile because it can be applied to existing rolling bearings without any processing of the rolling bearing, and there are no restrictions on the type of rolling bearing. Moreover, the spring plate is thin, which minimizes the increase in space required for the bearing unit to which it is installed.

[0043] Since the bearing unit of the present invention is equipped with the shaft grounding member of the present invention, the generation of wear particles and damage to the mating material are suppressed, the reduction in durability due to the generation of frictional heat is suppressed, and furthermore, it is highly versatile and does not increase the space required. [Brief explanation of the drawing]

[0044] [Figure 1] Figure 1 shows an example of an inner ring rotating type bearing unit as a shaft grounding member according to the first embodiment of the present invention. Figure (A) is a plan view thereof, Figure (B) is a cross-sectional view of (A) AA, and Figure (C) is an enlarged view showing the bent portion between the annular portion and the elastic portion in Figure (B). [Figure 2] Figure 2 is a cross-sectional view showing an example of a bearing unit incorporating the shaft grounding member shown in Figure 1. [Figure 3] Figure 3 is a cross-sectional view of a modified axial grounding member according to the present invention, corresponding to Figure 1(A). [Figure 4] Figure 4 shows an example of a shaft grounding member according to a second embodiment of the present invention, applied to a bearing unit on the outer ring rotation side. Figure (A) is a plan view thereof, and Figure (B) is a cross-sectional view of (A) AA. [Figure 5] Figure 5 is a cross-sectional view showing an example of a bearing unit incorporating the shaft grounding member shown in Figure 4. [Figure 6] Figure 6 is a cross-sectional view of a modified axial grounding member according to the present invention, corresponding to Figure 4(A). [Figure 7] Figure 7 is a cross-sectional view showing an example of an inner ring rotating type bearing unit equipped with a shaft grounding member according to the third embodiment of the present invention. [Figure 8] Figure 8 is a cross-sectional view showing an example of an inner ring rotating type bearing unit equipped with another shaft grounding member according to the third embodiment of the present invention. [Figure 9] Figure 9 is a cross-sectional view showing an example of an outer ring rotating type bearing unit equipped with a shaft grounding member according to the fourth embodiment of the present invention. [Figure 10]Figure 10 is a cross-sectional view showing an example of an outer ring rotating type bearing unit equipped with another shaft grounding member according to the fourth embodiment of the present invention. [Figure 11] Figure 11 shows an example of a shaft grounding member according to the fifth embodiment of the present invention, where Figure (A) is a plan view thereof, Figure (B) is a cross-sectional view of AA in Figure (A), and Figure (C) is an enlarged view showing the bent portion of the elastic part in Figure (B). [Figure 12] Figure 12 is a cross-sectional view showing an example of a bearing unit incorporating the shaft grounding member shown in Figure 11. [Figure 13] Figure 13 is a cross-sectional view of a modified axial grounding member according to the present invention, corresponding to Figure 11(A). [Figure 14] Figure 14 shows an example of an axial grounding member according to the sixth embodiment of the present invention, applied to an inner ring rotating type bearing unit. Figure (A) is a perspective view thereof, and Figure (B) is a plan view of Figure (A). [Figure 15] Figure 15 shows an example of a bearing unit incorporating the shaft grounding member shown in Figure 14. [Figure 16] Figure 16 shows an example of an axial grounding member according to the seventh embodiment of the present invention, applied to an outer ring rotating type bearing unit. Figure (A) is a perspective view thereof, and Figure (B) is a plan view of Figure (A). [Figure 17] Figure 17 is a cross-sectional view showing an example of a bearing unit incorporating the shaft grounding member shown in Figure 16. [Figure 18] Figure 18 is a cross-sectional view of a modified axial grounding member according to the present invention, corresponding to Figure 1(B). [Figure 19] Figure 19 is a cross-sectional view of a modified axial grounding member according to the present invention, corresponding to Figure 4(B). [Figure 20] Figure 20 is a cross-sectional view of a modified axial grounding member according to the present invention, corresponding to Figure 11(B). [Figure 21] Figure 21 is a cross-sectional view showing an example of a bearing unit equipped with the shaft grounding member shown in Figure 18. [Figure 22] Figure 22 is a cross-sectional view showing an example of a bearing unit equipped with the shaft grounding member shown in Figure 19. [Figure 23] Figure 23 is a cross-sectional view showing an example of a bearing unit equipped with the shaft grounding member shown in Figure 20. [Modes for carrying out the invention]

[0045] Embodiments of the present invention will be described in detail below with reference to the drawings. However, the present invention is not limited to the embodiments described below, and can be modified and implemented as desired without departing from the spirit of the invention. Hereafter, "shaft grounding member for rolling bearing" will be simply referred to as "shaft grounding member," and "rolling bearing unit" will be simply referred to as "bearing unit."

[0046] (First embodiment: Shaft grounding member and bearing unit for inner ring rotation) Figure 1 shows an example of a shaft grounding member of the present invention that is applied when the rotating ring is the inner ring. Figure (A) is a plan view thereof, Figure (B) is a cross-sectional view of AA in Figure (A), and Figure (C) is an enlarged view showing the bent portion between the annular portion and the elastic portion in Figure (B). Figure 2 is a cross-sectional view showing an example of a bearing unit incorporating the shaft grounding member shown in Figure 1.

[0047] As shown in Figure 1, the shaft grounding member 1A for inner ring rotation comprises a spring plate 10A, a soft conductive member 20, and a flexible member 25. The spring plate 10A has an annular portion 11A and a plurality of elastic portions 13A that are bent at the inner diameter end 12A of the annular portion 11A and extend radially from the annular portion 11A toward the radial center. Notches 16A are formed on both sides of the bent portion of the elastic portion 13A toward the annular portion 11A, to maintain the bent state of the elastic portion 13A.

[0048] The spring plate 10A is made entirely of a thin sheet of a conductive material such as metal. When the conductive material is metal, stainless steel is preferred because it is easy to process and less prone to rusting.

[0049] A soft conductive member 20 is attached to the bending surface of each elastic part 13A using an adhesive or the like.

[0050] As the flexible conductive member 20, a flexible base material into which a conductive material is mixed or supported, or commercially available products referred to as "conductive sheets" can be used. As the flexible base material, at least one selected from porous materials and resin-impregnated porous materials can be used. As the porous material, paper, cloth, nonwoven fabric, resin sheet, or a soft porous material such as sponge can be used. Of these, it is preferable to use at least one selected from soft porous materials such as nonwoven fabric, woven fabric and sponge, and resin-impregnated soft porous materials such as resin-impregnated nonwoven fabric, resin-impregnated woven fabric and sponge as the base material. When a resin-impregnated porous material is used as the base material for the flexible conductive member 20, the resin coats its skeleton, allowing the flexible conductive member 20 to be strengthened to the desired level while maintaining its flexible properties. Therefore, it is more preferable to use at least one selected from resin-impregnated nonwoven fabrics, resin-impregnated woven fabrics, and resin-impregnated soft porous materials such as sponges as the base material.

[0051] Furthermore, when using a resin-impregnated porous material as the base material, it is preferable to use a thermosetting resin as the resin to impregnate the porous material. Any thermosetting resin that can be impregnated into the base material and is thermosetting is acceptable, and examples include phenolic resin, modified phenolic resin, epoxy resin, modified epoxy resin, polyimide resin, silicone resin, polyester resin, polyurethane resin, and rubber resin.

[0052] As the conductive material to be mixed into or supported in a soft substrate, it is preferable to use at least one selected from metal fibers such as silver, copper, gold, aluminum, and stainless steel, and their pulverized or powdered forms, as well as conductive carbon fibers, and their pulverized or powdered forms.

[0053] The flexible member 25 is a flexible member and is attached to one side of the annular portion 11A of the spring plate 10A using an adhesive or the like. In this embodiment, the flexible member 25 is attached to the same side of the spring plate 10A as the side to which the soft conductive member 20 is attached.

[0054] The flexible member 25 is made of at least one material selected from porous materials and resin-impregnated porous materials. As the porous material, paper, cloth, nonwoven fabric, resin sheet, or a soft porous material such as sponge can be used, similar to the base material for the flexible conductive member 20. Of these, it is preferable to use at least one selected from soft porous materials such as nonwoven fabric, woven fabric, and sponge, and resin-impregnated soft porous materials such as resin-impregnated nonwoven fabric, resin-impregnated woven fabric, and sponge as the flexible member 25. When a resin-impregnated porous material is used as the flexible member 25, the resin coats its skeleton, allowing the flexible member 25 to be strengthened to a desired level while maintaining its flexible properties. Therefore, it is particularly preferable to use at least one selected from resin-impregnated nonwoven fabric, resin-impregnated woven fabric, or resin-impregnated soft porous material such as sponge as the base material.

[0055] Furthermore, when a resin-impregnated porous material is used as the flexible member 25, it is preferable to use a thermosetting resin as the resin to impregnate the porous material. Any thermosetting resin that can be impregnated into a substrate in the form of a varnish and that is thermosetting can be used, and examples include phenolic resin, modified phenolic resin, epoxy resin, modified epoxy resin, polyimide resin, silicone resin, polyester resin, polyurethane resin, and rubber resin.

[0056] Furthermore, the flexible member 25 may be conductive, and the above-mentioned porous body and resin-impregnated porous body can be used as a base material, with conductive material as described for the soft conductive member 20 mixed in or supported on this base material, or commercially available products called "conductive sheets" can be used. Therefore, the conductive flexible member 25 may be made of the same material as the soft conductive member 20, or they may be made of different materials. Also, the thickness of the flexible member 25 may be the same as that of the soft conductive member 20, or it may be a different thickness. For example, the thickness of the flexible member 25 may be greater than that of the soft conductive member 20 in order to improve flexibility.

[0057] Figure 2 shows a bearing unit 100A equipped with a rolling bearing 50 and fitted with a shaft grounding member 1A according to the first embodiment. The rolling bearing 50 has an outer ring 51 which is a fixed ring constituting one of the raceways, an inner ring 52 which is a rotating ring constituting the other raceway, and a plurality of rolling elements (balls) 53 which are held to roll freely between the outer ring 51 and the inner ring 52 by a cage 54. The outer ring 51 is fixed to a housing 70 which is a fixed member, and a shaft 60 which is a rotating member directly connected to a motor (not shown) is fitted into the inner diameter side of the inner ring 52. The rolling elements 53 roll smoothly with bearing lubricants such as lubricating oil or grease composition.

[0058] The shaft grounding member 1A is mounted on the bearing unit 100A such that the soft conductive member 20 abuts against the side surface 52a of the inner ring 52. At this time, the annular portion 11A of the spring plate 10A is sandwiched between the outer ring 51 and a conductive retaining member 80 separately provided on the housing 70, via a conductive spacer 30. Therefore, the annular portion 11A of the spring plate 10A is fixed to the housing 70 with the side surface to which the flexible member 25 is attached facing the spacer 30. In addition, the outer peripheral end surface 15A of the annular portion 11A of the spring plate 10A is fixed in contact with the housing 70.

[0059] As a result, in the bearing unit 100A according to the first embodiment, current from a motor (not shown) that drives the shaft 60 first flows to the inner ring 52. Then, the current flows from the soft conductive member 20 through the inner ring 52 to the elastic portion 13A and the annular portion 11A of the spring plate 10A, and then flows to the grounded housing 70 via the outer peripheral end face 15A of the annular portion 11A and the retaining member 80. In this way, by grounding the shaft 60 and the housing 70, the inside of the bearing is not energized, and the shaft voltage, which is the potential difference between the shaft 60 and the housing 70, can be significantly reduced. Therefore, electrolytic corrosion of the rolling bearing 50 can be prevented, and electromagnetic noise can be dissipated through the space between the shaft 60 and the housing 70.

[0060] Furthermore, if the flexible member 25 and the spacer 30 are conductive, the current flowing from the shaft 60 to the annular portion 11A also flows to the outer ring 51 side via the flexible member 25 and the spacer 30. Because the outer ring 51 has a large contact area with the housing 70, the current flowing through the outer ring 51 does not pass through the rolling elements 53 but flows to the housing 70. Therefore, the shaft voltage can be reduced even further, thereby preventing electrolytic corrosion and reducing electromagnetic noise.

[0061] Furthermore, in this embodiment, the shaft grounding member 1A has a flexible member 25, which is compressed by being sandwiched between the pressing member 80 and the outer ring 51. Therefore, a force is constantly generated in the flexible member 25 that tries to restore itself, and pressure is applied to the annular portion 11A from both axial sides, so that the shaft grounding member 1A can be securely fixed. As a result, even after long-term use, vibration and abnormal wear of the shaft grounding member 1A can be prevented, the contact state between the shaft grounding member 1A and the housing 70 and bearing 50 can be stabilized, and sufficient and stable conductivity can be ensured.

[0062] Furthermore, as the shaft 60 rotates, a slight gap may form in the mating surface between the outer ring 51 and the housing 70, which can cause creep. However, in this invention, the force exerted by the flexible member 25 to restore itself applies pressure to the annular portion 11A of the spring plate 10A of the shaft grounding member 1A, as well as to the outer ring 51. This ensures that the housing 70 and the outer ring 51 are securely fixed, suppressing rotational creep of the outer ring 51 and thereby reducing vibration and abnormal wear caused by rotational creep.

[0063] In particular, in a bearing unit 100A where the housing 70 is made of aluminum and the housing 70 and outer ring 51 are made of different materials, the dimensional change due to the difference in thermal expansion coefficients between the housing 70 and the outer ring 51 is large, making creep and loosening of the fit more likely to occur. Therefore, an increase in the pressing force of the flexible member 25 at the mounting portion of the shaft contact member 1A becomes more significant.

[0064] In the shaft grounding member 1A, the flexible conductive member 20 is configured to be able to contact the side surface 52a of the inner ring 52. The spring plate 10A is made of a thin plate and is elastic. Therefore, by pressing the annular portion 11A and the flexible member 25 of the shaft grounding member 1A toward the outer ring 51, the elastic force due to the pressing acts on the elastic portion 13A, causing it to be pushed open so that the bending angle θ shown in Figure 1(C) becomes larger. Consequently, the portion of the flexible conductive member 20 that was separated from the side surface 52a of the inner ring 52 in Figure 2 also moves toward the rolling bearing 50, and almost the entire flexible conductive member 20 comes into contact with the side surface 52a of the inner ring 52. This improves the conductivity between the flexible conductive member 20 and the inner ring 52, more effectively preventing electrolytic corrosion of the rolling bearing 50 and reducing electromagnetic noise.

[0065] The bending angle θ between the annular portion 11A and the elastic portion 13A should be appropriately set according to the length (L) of the elastic portion 13A and the size of the soft conductive member 20, so that when mounted on the bearing unit 100A, the soft conductive member 20 contacts the side surface 52a of the inner ring 52 of the rolling bearing 50. The biasing force of the soft conductive member 20 on the side surface 52a of the inner ring 52 of the rolling bearing 50 can also be adjusted by the bending angle θ; the biasing force can be increased by decreasing the bending angle θ, and conversely, the biasing force can be decreased by increasing the bending angle θ.

[0066] In this embodiment, since the side surface 52a of the inner ring 52 is in contact with the soft conductive member 20, the side surface 52a of the inner ring 52 is not damaged, and the reduction in the rotational torque of the inner ring 52 can be suppressed. Furthermore, since the biasing force of the soft conductive member 20 on the side surface of the inner ring 52 by the spring plate 10A is not very strong, the generation of wear particles can be suppressed.

[0067] In the first embodiment, the outer peripheral end surface 15A of the annular portion 11A, the flexible member 25, and the spacer 30 are in contact with the housing 70. However, they may not be in contact with the housing 70, but instead be held between the outer ring 51 by the retaining member 80. Even in that case, the current flowing through the annular portion 11A flows to the housing 70 via the retaining member 80, or via the retaining member 80, the flexible member 25, the spacer 30, and the outer ring 51, so the conductivity does not decrease. Alternatively, the annular portion 11A of the shaft grounding member 1A may be pressed directly against the side surface of the outer ring 51 with a conductive spacer 30 interposed between them, without the presence of a retaining member 80, and fixed in contact with the housing 70.

[0068] Furthermore, the thickness of the spacer 30 should be determined considering the amount of pressure applied by the spring plate 10A, as well as the thickness of the soft conductive member 20 and the flexible member 25. Alternatively, the flexible member 25 of the shaft grounding member 1A may directly contact the side surface of the outer ring 51 without the spacer 30.

[0069] Figure 3 shows a modified example of the shaft grounding member shown in Figure 1. In this modified example, the soft conductive member 20 and the flexible member 25 are composed of a single member 99 mounted on the surface facing the inner ring 52 and the spacer 30. In this way, since the flexible member 25 and the soft conductive member 20 are combined into a single component 99, it is no longer necessary to manufacture the flexible member 25 and the soft conductive member 20 separately, thus reducing manufacturing costs. Furthermore, the single component 99 comprising the flexible member 25 and the soft conductive member 20 can be precisely bonded to the spring plate 10A in one go, improving the workability of the bonding process and enabling the supply of a shaft grounding member of stable quality. In this embodiment, the single member 99 is bonded to the area excluding the peripheral edge of the notch 16A, but the single member 99 may be bonded to the entire surface of the spring plate 10A. If the single member 99 is not bonded to the peripheral edge of the notch 16A, the bent state of the elastic portion 13A can be sufficiently maintained. On the other hand, if the single member 99 has the same shape as the spring plate 10A, manufacturing costs can be reduced by bonding the single member 99 to the shaft grounding member 1A and then shaping the shaft grounding member 1A.

[0070] (Second embodiment: Shaft grounding member and bearing unit for outer ring rotation) In the first embodiment, the case in which the inner ring 52 of the rolling bearing 50 is a rotating ring was described. In the second embodiment, a bearing unit in which the outer ring 51 is a rotating ring will be described. Figure 4 shows a shaft grounding member for the rotation of the outer ring, with Figure (A) being a plan view thereof and Figure (B) being a cross-sectional view of Figure (A) AA. Figure 5 is a cross-sectional view showing an example of a bearing unit incorporating the shaft grounding member shown in Figure 4. In the bearing unit according to the second embodiment, the same reference numerals are used for the same components as in the first embodiment, and their detailed descriptions are omitted or simplified.

[0071] As shown in Figure 4, the shaft grounding member 1B for outer ring rotation comprises a spring plate 10B, a soft conductive member 20, and a flexible member 25. The spring plate 10B has an annular portion 11B and a plurality of elastic portions 13B that are bent at the outer diameter side end 12B of the annular portion 11B and extend radially from the annular portion 11B toward the outer circumference in the radial direction. As shown in Figure 5, the elastic portions 13B are bent toward the right in the figure so that they face the outer ring 51 of the rolling bearing 50 when mounted on the bearing unit 100B. In addition, arc-shaped notches 16B are formed on both sides of the bent portion of the elastic portion 13B toward the annular portion 11B.

[0072] As shown in Figure 5, the bearing unit 100B according to the second embodiment includes a rolling bearing 50 and is fitted with the shaft grounding member 1B shown in Figure 4. The inner ring 52 of the rolling bearing 50 is fixed to a fixed member 75, and a rotating member 65 is fitted to the outer ring 51. The shaft grounding member 1B is mounted on the bearing unit 100B such that the soft conductive member 20 abuts against the side surface 51a of the outer ring 51.

[0073] Furthermore, the annular portion 11B of the shaft grounding member 1B is pressed against the side surface of the inner ring 52 by the retaining member 80 with a conductive spacer 30 interposed between them. Therefore, the inner circumferential end surface of the annular portion 11B of the spring plate 10B is fixed in contact with the fixing member 75, and the soft conductive member 20 is able to contact the side surface of the outer ring 51.

[0074] In the second embodiment, current from a motor (not shown) that drives the rotating member 65 flows to the outer ring 51. The current then flows from the soft conductive member 20 through the outer ring 51 to the elastic portion 13B and the annular portion 11B of the spring plate 10B, and through the inner circumferential end surface 15B of the annular portion 11B and the conductive retaining member 80 to the grounded fixed member 75. By grounding the rotating member 65 and the fixed member 75 in this way, the inside of the bearing is not energized, and the shaft voltage, which is the potential difference between the rotating member and the fixed member, can be significantly reduced. Therefore, electrolytic corrosion of the rolling bearing 50 can be prevented, and electromagnetic noise can be reduced.

[0075] Similar to the first embodiment, when the flexible member 25 and the spacer 30 are conductive, the current flowing from the rotating member 65 to the annular portion 11B also flows to the inner ring 52 side via the flexible member 25 and the spacer 30. Because the inner ring 52 has a large contact area with the fixed member 75, the current flowing through the inner ring 52 does not pass through the rolling elements 53 but flows to the fixed member 75. Therefore, the shaft voltage can be reduced even further, thereby preventing electrolytic corrosion and reducing electromagnetic noise.

[0076] Similar to the first embodiment, the shaft grounding member 1B has a flexible member 25, which is compressed by being held between the pressing member 80 and the inner ring 52. Therefore, a restorative force is constantly generated in the flexible member 25, and pressure is applied to the annular portion 11B from both axial sides, so that the shaft grounding member 1B can be securely fixed. As a result, even after long-term use, vibration and abnormal wear of the shaft grounding member 1B can be prevented, the contact state between the shaft grounding member 1B and the fixing member 75 and bearing 50 can be stabilized, and sufficient and stable conductivity can be ensured.

[0077] Furthermore, the force exerted by the flexible member 25 as it attempts to restore itself applies pressure to the annular portion 11B of the spring plate 10B of the shaft contact member 1B, as well as to the inner ring 52. Therefore, the fixing member 75 and the inner ring 52 can be securely fixed, making it possible to suppress the occurrence of rotational creep of the inner ring 52, and thereby suppressing vibrations and abnormal wear caused by rotational creep.

[0078] In particular, in a bearing unit 100B where the fixed member 75 is made of aluminum and the fixed member 75 and the inner ring 52 are made of different materials, the dimensional change due to the difference in thermal expansion coefficients between the fixed member 75 and the inner ring 52 is large, making creep and loosening of the fit more likely to occur. Therefore, an increase in the pressing force of the flexible member 25 at the mounting portion of the shaft contact member 1B becomes more significant.

[0079] Furthermore, in this embodiment as well, the biasing force exerted by the spring plate 10B on the side surface of the outer ring 51 of the soft conductive member 20 is not very strong, so wear particles are less likely to be generated.

[0080] Furthermore, by adjusting the pressing force applied by the retaining member 80 against the outer ring 51 and increasing the contact area between the soft conductive member 20 and the side surface 51a of the outer ring 51, electrolytic corrosion of the rolling bearing 50 can be prevented more effectively.

[0081] Furthermore, in this embodiment as well, the flexible member 25 of the shaft contact member 1B may directly contact the side surface of the inner ring 52 without providing the spacer 30. Furthermore, the inner circumferential end surface 15B of the annular portion 11B and the spacer 30 may be in contact with the fixing member 75, or they may not be in contact with the fixing member 75 but may be held between the inner ring 52 by the retaining member 80.

[0082] Furthermore, as a modified example of the shaft grounding member of the second embodiment, as shown in Figure 6, the soft conductive member 20 and the flexible member 25 may be a single member 99 mounted on the surface facing the outer ring 51 and the spacer 30.

[0083] (Third embodiment: Shaft grounding member and bearing unit for inner ring rotation) Figure 7 shows the case in which the shaft grounding member 1A is mounted on a bearing unit in which the rotating ring is the inner ring, similar to the first embodiment. In the bearing unit according to the third embodiment, the same reference numerals are used for the same components as in the first embodiment, and their detailed descriptions are omitted or simplified.

[0084] In the third embodiment, the shaft 60, which is a rotating member into which the inner ring 52 is fitted, has a stepped surface 60c formed thereon that is smaller in diameter than the fitting surface 60b into which the inner ring 52 is fitted. The soft conductive member 20 is in contact with the surface of the elastic portion 13A that faces the shaft 60 in the axial direction, specifically, the side surface 60a between the fitting surface 60b into which the inner ring 52 is fitted and the stepped surface 60c.

[0085] The shaft grounding member 1A is mounted on the housing 70 by elastically deforming the elastic portion 13A so that the soft conductive member 20 comes into contact with the side surface 60a of the shaft 60. The annular portion 11A of the spring plate 10A is sandwiched between a flange portion 71 and an outer ring 51, which are provided to protrude toward the inner diameter side of the housing 70 via a conductive spacer 30. Therefore, the annular portion 11A of the spring plate 10A is fixed to the housing 70 with the side surface to which the flexible member 25 is attached facing toward the spacer 30. In addition, the outer peripheral end surface 15A of the annular portion 11A of the spring plate 10A is fixed in contact with the housing 70.

[0086] In the inner ring rotating bearing unit 100A shown in Figure 7, the current from the shaft 60 flows from the soft conductive member 20 through the side surface 60a of the shaft 60 to the elastic portion 13A and the annular portion 11A of the spring plate 10A. Subsequently, the current flows to the grounded housing 70 via the outer peripheral end surface 15A of the annular portion 11A or the flange portion 71 of the housing 70. In this way, by grounding the rotating member, the shaft 60, and the fixed member, the housing 70, current does not flow inside the bearing, and the shaft voltage, which is the potential difference between the rotating member and the fixed member, can be significantly reduced. Therefore, electrolytic corrosion of the rolling bearing 50 can be prevented, and electromagnetic noise can be reduced.

[0087] Furthermore, if the flexible member 25 and the spacer 30 are conductive, the current flowing from the shaft 60 to the annular portion 11A also flows to the outer ring 51 side via the flexible member 25 and the spacer 30. Because the outer ring 51 has a large contact area with the housing 70, the current flowing through the outer ring 51 does not pass through the rolling elements 53 but flows to the housing 70. Therefore, the shaft voltage can be reduced even further, thereby preventing electrolytic corrosion and reducing electromagnetic noise.

[0088] Furthermore, in this embodiment, the shaft grounding member 1A has a flexible member 25, which is compressed by being sandwiched between the flange portion 71 and the outer ring 51 of the housing 70. Therefore, a force is constantly generated in the flexible member 25 to restore its shape, and pressure is applied to the annular portion 11A from both axial sides, so that the shaft grounding member 1A can be securely fixed. As a result, even after long-term use, vibration and abnormal wear of the shaft grounding member 1A can be prevented, the contact state between the shaft grounding member 1A and the housing 70 and bearing 50 can be stabilized, and sufficient and stable conductivity can be ensured.

[0089] Furthermore, the force exerted by the flexible member 25 to restore itself applies pressure to the annular portion 11A of the spring plate 10A of the shaft grounding member 1A, as well as to the outer ring 51. Therefore, the housing 70 and the outer ring 51 can be securely fixed, making it possible to suppress the occurrence of rotational creep of the outer ring 51, and thereby suppressing vibrations and abnormal wear caused by rotational creep.

[0090] In particular, in a bearing unit 100A where the housing 70 is made of aluminum and the housing 70 and outer ring 51 are made of different materials, the dimensional change due to the difference in thermal expansion coefficients between the housing 70 and the outer ring 51 is large, making creep and loosening of the fit more likely to occur. Therefore, an increase in the pressing force of the flexible member 25 at the mounting portion of the shaft contact member 1A becomes more significant.

[0091] Furthermore, similar to the first embodiment, the biasing force exerted by the spring plate 10A on the side surface of the shaft 60 by the soft conductive member 20 is not very strong, so wear particles are less likely to be generated.

[0092] As shown in Figure 8, in this embodiment, the shaft 60 may be provided with a flange portion 62 that protrudes outward from the fitting surface 60b, and the soft conductive member 20 may be in contact with the side surface 60a of this flange portion 62.

[0093] In particular, in the bearing unit 100A shown in Figure 8, the position where the soft conductive member 20 contacts the side surface 60a of the shaft 60 is smaller in diameter than the position where it contacts the side surface 52a of the inner ring 52, as shown in Figure 2. This allows the peripheral speed of the side surface 60a of the shaft 60 to be reduced, further suppressing the generation of wear particles and drag losses.

[0094] Unlike the first embodiment, the third embodiment does not involve contact between the shaft contact member 1A and the side surface 52a of the inner ring 52, thereby improving the design flexibility of the rolling bearing, such as the installation of a snap ring.

[0095] (Fourth embodiment: Shaft grounding member and bearing unit for outer ring rotation) Figure 9 shows the case where the shaft grounding member 1B is mounted on a bearing unit in which the rotating ring is the outer ring 51, similar to the second embodiment. In the bearing unit according to the fourth embodiment, the same reference numerals are used for the same components as in the second embodiment, and their detailed descriptions are omitted or simplified.

[0096] In the fourth embodiment, the rotating member 65 into which the outer ring 51 is fitted has a stepped surface 65c with a larger diameter than the fitting surface 65b into which the outer ring 51 is fitted. The soft conductive member 20 is mounted on the surface of the elastic portion 13B that faces the rotating member 65 in the axial direction, specifically on the surface facing the side surface 65a between the fitting surface 65b into which the outer ring 51 is fitted and the stepped surface 65c. Therefore, the soft conductive member 20 can come into contact with the side surface 65a of the rotating member 65.

[0097] As shown in Figure 9, in the outer ring rotating type bearing unit 100B, the soft conductive member 20 of the shaft grounding member 1B is mounted on the fixed member 75 so that it abuts against the side surface 65a of the rotating member 65. At this time, the annular portion 11B of the spring plate 10B is sandwiched between the inner ring 52 and the flange portion 76 of the fixed member 75 via the conductive spacer 30. Therefore, the annular portion 11B of the spring plate 10B is fixed to the fixed member 75 with the side surface on which the flexible member 25 is attached facing the spacer 30. In addition, the inner circumferential end surface 15B of the annular portion 11A of the spring plate 10A is fixed in contact with the fixed member 75.

[0098] In the bearing unit 100B shown in Figure 9, the current from the motor (not shown) that drives the rotating member 65 flows from the soft conductive member 20 through the side surface 65a of the rotating member 65, through the elastic portion 13B and the annular portion 11B of the spring plate 10B, and then through the inner circumferential end surface 15B of the annular portion 11B and the flange portion 76 to the grounded fixed member. By grounding the rotating member 65 and the fixed member 75 in this way, the inside of the bearing is not energized, and the shaft voltage, which is the potential difference between the rotating member and the fixed member, can be significantly reduced. Therefore, electrolytic corrosion of the rolling bearing 50 can be prevented, and electromagnetic noise can be reduced.

[0099] Here, as in the second embodiment, if the flexible member 25 and the spacer 30 are conductive, the current flowing from the rotating member 65 to the annular portion 11B also flows to the inner ring 52 side via the flexible member 25 and the spacer 30. Since the inner ring 52 has a large contact area with the fixed member 75, the current flowing through the inner ring 52 does not pass through the rolling elements 53 but flows to the fixed member 75. Therefore, the shaft voltage can be reduced even further, thereby preventing electrolytic corrosion and reducing electromagnetic noise.

[0100] Furthermore, the shaft grounding member 1B has a flexible member 25, which is clamped and compressed between the flange portion 76 and the inner ring 52 of the fixed member 75. Therefore, a restorative force is constantly generated in the flexible member 25, and pressure is applied to the annular portion 11B from both axial sides, so that the shaft grounding member 1B can be securely fixed. As a result, even after long-term use, vibration and abnormal wear of the shaft grounding member 1B can be prevented, the contact state between the shaft grounding member 1B and the fixed member 75 and bearing 50 can be stabilized, and sufficient and stable conductivity can be ensured.

[0101] The force exerted by the flexible member 25 as it attempts to restore itself applies pressure to the annular portion 11B of the spring plate 10B of the shaft contact member 1B, as well as to the inner ring 52. Therefore, the fixing member 75 and the inner ring 52 can be securely fixed, making it possible to suppress the occurrence of rotational creep of the inner ring 52, and thereby suppressing vibrations and abnormal wear caused by rotational creep.

[0102] In particular, in a bearing unit 100B where the fixed member 75 is made of aluminum and the fixed member 75 and the inner ring 52 are made of different materials, the dimensional change due to the difference in thermal expansion coefficients between the fixed member 75 and the inner ring 52 is large, making creep and loosening of the fit more likely to occur. Therefore, an increase in the pressing force of the flexible member 25 at the mounting portion of the shaft contact member 1B becomes more significant.

[0103] Furthermore, similar to the second embodiment, the biasing force exerted by the spring plate 10B on the side surface of the rotating member 65 by the soft conductive member 20 is not very strong, so wear particles are less likely to be generated.

[0104] As shown in Figure 10, in this embodiment, the rotating member 65 may be provided with a flange portion 67 that protrudes inward from the fitting surface 65b, and the soft conductive member 20 may come into contact with the side surface 65a of this flange portion 67.

[0105] In particular, in the bearing unit 100B shown in Figure 10, the position where the soft conductive member 20 contacts the side surface 65a of the rotating member 65 is smaller in diameter than the position where it contacts the side surface 51a of the outer ring 51, as shown in Figure 5. This allows the peripheral speed of the side surface 65a of the rotating member 65 to be reduced, further suppressing the generation of wear particles and drag losses.

[0106] Furthermore, unlike the second embodiment, the fourth embodiment does not have the shaft contact member 1B in contact with the side surface 51a of the outer ring 51, thus improving the design flexibility of the rolling bearing, such as the installation of a snap ring.

[0107] (Fifth embodiment: Shaft grounding member and bearing unit for inner ring rotation, equipped with a single elastic part) Figure 11 shows an example of a shaft grounding member according to the fifth embodiment of the present invention, where Figure (A) is a plan view thereof, Figure (B) is a cross-sectional view of Figure (A) AA, and Figure (C) is an enlarged view showing the bent portion between the annular portion and the elastic portion in Figure (B). Figure 12 is a cross-sectional view showing an example of a bearing unit incorporating the shaft grounding member shown in Figure 11. In the bearing unit according to the fifth embodiment, the same reference numerals are used for the same components as in the first embodiment, and their detailed descriptions are omitted or simplified.

[0108] As shown in Figure 11, the axial grounding member 1C comprises a spring plate 10C, a soft conductive member 20, and a flexible member 25. The spring plate 10C has an annular portion 11C and a single elastic portion 13C that is bent at the inner circumferential end 12C of the annular portion 11C and extends continuously from the annular portion 11C toward the radial center. The elastic portion 13C is bent starting from an elastic base portion 14C. The soft conductive member 20 is bonded to the bent side surface of the elastic portion 13C, and the flexible member 25 is bonded to the same side of the annular portion 11C as the soft conductive member 20.

[0109] As shown in Figure 12, the shaft grounding member 1C is mounted on the bearing unit 100C such that the soft conductive member 20 abuts against the side surface 60a of the shaft 60. At this time, the annular portion 11C of the spring plate 10C is sandwiched between the outer ring 51 and a conductive retaining member 80 separately provided on the housing 70 via a conductive spacer 30. Therefore, the annular portion 11C of the spring plate 10C is fixed to the housing 70 with the side surface to which the flexible member 25 is attached facing the spacer 30. In addition, the outer peripheral end surface 15C of the annular portion 11C of the spring plate 10C is fixed in contact with the housing 70.

[0110] In the fifth embodiment, current from a motor (not shown) that drives the shaft 60 flows from the soft conductive member 20 to the elastic portion 13C and the annular portion 11C of the spring plate 10C, and then flows to the grounded housing 70 via the outer peripheral end face 15C of the annular portion 11C and the conductive retaining member 80. By grounding the rotating member, the shaft 60, and the fixed member, the housing 70 in this way, current does not flow inside the bearing, and the shaft voltage, which is the potential difference between the rotating member and the fixed member, can be significantly reduced. Therefore, electrolytic corrosion of the rolling bearing 50 can be prevented, and electromagnetic noise can be reduced.

[0111] If the flexible member 25 and the spacer 30 are conductive, the current flowing from the shaft 60 to the annular portion 11C also flows to the outer ring 51 side via the flexible member 25 and the spacer 30. Because the outer ring 51 has a large contact area with the housing 70, the current flowing through the outer ring 51 does not pass through the rolling elements 53 but flows to the housing 70. Therefore, the shaft voltage can be reduced even further, thereby preventing electrolytic corrosion and reducing electromagnetic noise.

[0112] In this embodiment, the shaft grounding member 1C has a flexible member 25, which is compressed by being sandwiched between the pressing member 80 and the outer ring 51. Therefore, a force is constantly generated in the flexible member 25 to restore its shape, and pressure is applied to the annular portion 11C from both axial sides, so that the shaft grounding member 1C can be securely fixed. As a result, even after long-term use, vibration and abnormal wear of the shaft grounding member 1C can be prevented, the contact state between the shaft grounding member 1C and the housing 70 and bearing 50 can be stabilized, and sufficient and stable conductivity can be ensured.

[0113] Furthermore, the force exerted by the flexible member 25 as it attempts to restore itself applies pressure to the annular portion 11C of the spring plate 10C of the shaft grounding member 1C, as well as to the outer ring 51. Therefore, the housing 70 and the outer ring 51 can be securely fixed together, making it possible to suppress the occurrence of rotational creep of the outer ring 51, and thereby suppressing vibrations and abnormal wear caused by rotational creep.

[0114] In particular, in a bearing unit 100C where the housing 70 is made of aluminum and the housing 70 and outer ring 51 are made of different materials, the dimensional change due to the difference in thermal expansion coefficients between the housing 70 and the outer ring 51 is large, making creep and loosening of the fit more likely to occur. Therefore, an increase in the pressing force of the flexible member 25 at the mounting portion of the shaft contact member 1C becomes more significant.

[0115] Furthermore, similar to the first embodiment, the biasing force exerted by the spring plate 10C on the side surface of the shaft 60 by the soft conductive member 20 is not very strong, so wear particles are less likely to be generated.

[0116] Furthermore, in the fifth embodiment, the outer peripheral end face 15C of the annular portion 11C and the spacer 30 are in contact with the housing 70, but they may not be in contact with the housing 70 and may be held between the outer ring 51 and the retaining member 80. In that case, the current flowing through the annular portion 11C flows to the housing 70 via the outer ring 51 and the conductive retaining member 80. Note that since the outer ring 51 has a large contact area with the housing 70, the current flowing through the outer ring 51 does not pass through the rolling elements 53 and flows to the housing 70.

[0117] Furthermore, in the bearing unit 100C, the soft conductive member 20 is in contact with the side surface 60a of the shaft 60, resulting in an even lower peripheral speed compared to the case where the soft conductive member 20 is in contact with the side surface of the inner ring 52. Therefore, compared to other embodiments, it is possible to further suppress the generation of wear particles and drag losses. Note that since the peripheral speed is lowest near the center of the shaft, it is more preferable for the soft conductive member 20 to be in contact near the center of the shaft.

[0118] Figure 13 shows a modified example of the shaft grounding member shown in Figure 11. Therefore, in this embodiment as well, the soft conductive member 20 and the flexible member 25 are composed of a single member 99 mounted on the surface facing the shaft 60 and the spacer 30.

[0119] (Sixth embodiment: Shaft grounding member and bearing unit for inner ring rotation, equipped with an elastic portion bent in the axial direction) Figure 14 shows an example of a shaft grounding member according to the sixth embodiment of the present invention, where Figure (A) is a perspective view thereof and Figure (B) is a plan view thereof. Figure 15 is a cross-sectional view showing an example of a bearing unit incorporating the shaft grounding member shown in Figure 14. In the bearing unit according to the sixth embodiment, the same reference numerals are used for the same components as in the first embodiment, and their detailed descriptions are omitted or simplified.

[0120] As shown in Figure 14, the shaft grounding member 1D comprises a spring plate 10D, a soft conductive member 20, and a flexible member 25. The spring plate 10D has an annular portion 11D, a connecting portion 12D that extends continuously from the annular portion 11D toward the radial center, and an elastic portion 13D that bends from the tip of the connecting portion 12D. The elastic portion 13D is composed of a first flat plate portion 13b that extends in the axial direction of the rotating ring of the rolling bearing, and a curved plate portion 13a that extends from the first flat plate portion 13b while curving along the circumferential direction of the shaft (rotating member). That is, the elastic portion 13D extends in the circumferential direction relative to the connecting portion 12D. Note that "axial direction of the rotating ring" is synonymous with "axial direction of the rotating member". A linearly extending bent portion 21D is formed between the connecting portion 12D and the first flat plate portion 13b, and notches 17D are formed on both sides of the bent portion 21D, which makes it easier to bend the elastic portion 13D. In addition, notches 18D are formed on both sides of the boundary portion 16D between the first flat plate portion 13b and the curved plate portion 13a, which makes it easier to bend the curved plate portion 13a. Furthermore, the flexible member 25 is attached to the side of the elastic portion 13D on which the soft conductive member 20 is attached, on the front and back surfaces of the annular portion 11D of the spring plate 10D, where the elastic portion 13D is bent.

[0121] Figure 15 shows a bearing unit 100D equipped with a rolling bearing 50 and fitted with a shaft grounding member 1D according to the fifth embodiment. The soft conductive member 20 is attached to the elastic portion 13D of the spring plate 10D, on the surface (lower side in Figure 15) facing the circumferential surface 60d of the shaft 60.

[0122] Furthermore, the annular portion 11D of the spring plate 10D is sandwiched between a flange portion 71 and an outer ring 51, which are provided to protrude toward the inner diameter side of the housing 70 via a conductive spacer 30. Therefore, the annular portion 11D of the spring plate 10D is fixed to the housing 70 with the side to which the flexible member 25 is attached facing toward the spacer 30. Also, the outer peripheral end face 15D of the annular portion 11D of the spring plate 10D is fixed in contact with the housing 70. Therefore, the soft conductive member 20 can contact at least a portion of the circumferential surface 60d of the shaft 60.

[0123] In the bearing unit 100D configured in this way, current from a motor (not shown) that drives the shaft 60 flows from the circumferential surface 60d of the shaft 60 to the soft conductive member 20. Subsequently, the current flows through the soft conductive member 20 to the elastic portion 13D, connecting portion 12D, and annular portion 11D of the spring plate 10D, and then flows to the grounded housing 70 via the outer peripheral end surface 15D of the annular portion 11D and the flange portion 71. In this way, the shaft grounding member 1D grounds the rotating member shaft 60 and the fixed member housing 70, so that current does not flow inside the bearing, and the shaft voltage, which is the potential difference between the shaft 60 and the housing 70, can be significantly reduced. Therefore, electrolytic corrosion of the rolling bearing 50 can be prevented, and electromagnetic noise can be dissipated through the space between the shaft 60 and the housing 70.

[0124] Furthermore, if the flexible member 25 and the spacer 30 are conductive, the current flowing from the shaft 60 to the annular portion 11D also flows to the outer ring 51 side via the flexible member 25 and the spacer 30. Because the outer ring 51 has a large contact area with the housing 70, the current flowing through the outer ring 51 does not pass through the rolling elements 53 but flows to the housing 70. Therefore, the shaft voltage can be reduced even further, thereby preventing electrolytic corrosion and reducing electromagnetic noise.

[0125] Furthermore, in this embodiment, the shaft grounding member 1D has a flexible member 25, which is compressed by being sandwiched between the flange portion 71 and the outer ring 51 of the housing 70. Therefore, a force is constantly generated in the flexible member 25 to restore its shape, and pressure is applied to the annular portion 11D from both axial sides, so that the shaft grounding member 1D can be securely fixed. As a result, even after long-term use, vibration and abnormal wear of the shaft grounding member 1D can be prevented, the contact state between the shaft grounding member 1D and the housing 70 and bearing 50 can be stabilized, and sufficient and stable conductivity can be ensured.

[0126] Furthermore, the force exerted by the flexible member 25 as it attempts to restore itself applies pressure to the annular portion 11D of the spring plate 10D of the shaft grounding member 1D, as well as to the outer ring 51. Therefore, the housing 70 and the outer ring 51 can be securely fixed together, making it possible to suppress the occurrence of rotational creep of the outer ring 51, and thereby suppressing vibrations and abnormal wear caused by rotational creep.

[0127] In particular, in a bearing unit 100D in which the housing 70 is made of aluminum and the housing 70 and outer ring 51 are made of different materials, the dimensional change due to the difference in thermal expansion coefficients between the housing 70 and the outer ring 51 is large, making creep and loosening of the fit more likely to occur. Therefore, an increase in the pressing force of the flexible member 25 at the mounting portion of the shaft contact member 1D becomes more significant.

[0128] Furthermore, as shown in Figure 14(B), the first flat plate portion 13b and the curved plate portion 13a of the elastic portion 13D may be bent at their boundary. When the angle between the first flat plate portion 13b and the tangent near the boundary line of the curved plate portion 13a is defined as the bending angle θ, the bending angle θ can be appropriately set so that the soft conductive member 20 contacts the circumferential surface 60d of the shaft 60. The biasing force of the soft conductive member 20 on the circumferential surface 60d of the shaft 60 can also be adjusted by this bending angle θ. By reducing the bending angle θ, the elastic portion 13D of the shaft grounding member 1D becomes elastically deformed, thereby increasing the biasing force of the soft conductive member 20 on the shaft 60. As a result, the gap between the shaft 60 and the circumferential surface 60d is reduced, and the contact area is increased, thereby stably reducing the axial voltage between the rotating member and the fixed member. Conversely, by increasing the bending angle θ, the biasing force is weakened, and the generation of wear particles can be suppressed. Furthermore, the extension length L of the curved plate portion, the size of the soft conductive member 20, and the curvature of the curved plate portion 13a can also be set as appropriate, and by adjusting these, the aforementioned axial voltage can be reduced more stably.

[0129] Furthermore, since the biasing force exerted by the spring plate 10D on the circumferential surface 60d of the shaft 60 by the soft conductive member 20 is not very strong, wear particles are less likely to be generated.

[0130] In Figure 15, the outer peripheral end surface 15D of the annular portion 11D and the spacer 30 are in contact with the housing 70, but a configuration in which they do not contact the housing 70 is also possible.

[0131] The annular portion 11D and the spacer 30 may be sandwiched between the outer ring 51 by the flange portion 71 or a conductive retaining member that replaces the flange portion 71. In that case, the current flowing through the annular portion 11D flows to the housing 70 via the outer ring 51 or the retaining member.

[0132] Furthermore, although the curved plate portion 13a extends from one side of the first flat plate portion 13b in Figure 14, it may extend from both sides of the first flat plate portion 13b. The shape of the first flat plate portion 13b does not need to perfectly match the curvature of the shaft in the circumferential direction.

[0133] Here, there is no limit to the thickness of the spacer 30, and as long as the connecting portion 12D of the shaft grounding member 1D is configured not to come into contact with the inner ring 52, the flexible member 25 of the shaft grounding member 1D may come into direct contact with the side surface of the outer ring 51 without the spacer 30 being interposed.

[0134] (Seventh embodiment: Shaft grounding member and bearing unit for outer ring rotation, equipped with an axially bent elastic portion) In the sixth embodiment, a case was described in which the inner ring 52 of the rolling bearing 50 is a rotating ring. In the seventh embodiment, a bearing unit in which the outer ring 51 is a rotating ring will be described. Figure 16 is a diagram showing the shaft grounding member for the rotation of the outer ring, with Figure (A) being a perspective view thereof and Figure (B) being a plan view of Figure (A). In the bearing unit according to the seventh embodiment, the same reference numerals are used for the same components as in the sixth embodiment, and their detailed descriptions are omitted or simplified.

[0135] As shown in Figure 16, the shaft grounding member 1E for outer ring rotation comprises a spring plate 10E, a soft conductive member 20, and a flexible member 25. The spring plate 10E has an annular portion 11E, a connecting portion 12E that extends radially outward from the annular portion 11E, and an elastic portion 13E that bends from the tip of the connecting portion 12E. The elastic portion 13E is composed of a first flat plate portion 13b that is bent in the axial direction of the rotating member, which will be described later, and a curved plate portion 13a that extends from the first flat plate portion 13b while curving along the circumferential direction of the rotating member 65.

[0136] A soft conductive member 20 is attached to the side of the curved plate portion 13a facing the inner circumferential surface 65d of the rotating member 65, and a flexible member 25 is attached to the side of the annular portion 11E facing the inner ring using adhesive or the like. The spring plate 10E, the soft conductive member 20, and the flexible member 25 constitute the shaft grounding member 1E.

[0137] Figure 17 shows a bearing unit 100E equipped with a rolling bearing 50 and fitted with the shaft grounding member 1E according to the seventh embodiment. The inner ring 52 of the rolling bearing 50 is fixed to the fixed member 75, and the rotating member 65 is mounted on the outer ring 51. The shaft grounding member 1E is mounted on the bearing unit 100E such that the flexible conductive member 20 abuts against the inner circumferential surface 65d of the rotating member 65. At this time, the annular portion 11E of the spring plate 10E is sandwiched between the inner ring 52 and the flange portion 76 of the fixing member 75 via the conductive spacer 30. Therefore, the annular portion 11E of the spring plate 10E is fixed to the fixing member 75 with the side on which the flexible member 25 is attached facing the spacer 30. In addition, the inner circumferential end surface 15E of the annular portion 11E of the spring plate 10E is fixed in contact with the fixing member 75, and the flexible conductive member 20 is fixed in contact with the inner circumferential surface 65d of the rotating member 65.

[0138] As a result, in the bearing unit 100E according to the seventh embodiment, current from a motor (not shown) that drives the rotating member 65 first flows to the flexible conductive member 20. Then, the current flows through the flexible conductive member 20 to the elastic portion 13E, the connecting portion 12E, and the annular portion 11E of the spring plate 10E, and through the inner circumferential end face 15E and flange portion 76 of the annular portion 11E, it flows to the grounded fixed member 75. In this way, by grounding the rotating member 65 and the fixed member 75, the inside of the bearing is not energized, and the shaft voltage, which is the potential difference between the rotating member and the fixed member, can be significantly reduced. Therefore, electrolytic corrosion of the rolling bearing 50 can be prevented, and electromagnetic noise can be reduced.

[0139] Furthermore, if the flexible member 25 and the spacer 30 are conductive, the current flowing from the rotating member 65 to the annular portion 11E also flows to the inner ring 52 side via the flexible member 25 and the spacer 30. Because the inner ring 52 has a large contact area with the fixed member 75, the current flowing through the inner ring 52 does not pass through the rolling elements 53 but flows to the fixed member 75. Therefore, the shaft voltage can be reduced even further, thereby preventing electrolytic corrosion and reducing electromagnetic noise.

[0140] Furthermore, in this embodiment, the shaft grounding member 1E has a flexible member 25, which is compressed by being sandwiched between the flange portion 76 and inner ring 52 of the fixed member 75. Therefore, a force is constantly generated in the flexible member 25 to restore its shape, and pressure is applied to the annular portion 11E from both axial sides, so that the shaft grounding member 1E can be securely fixed. As a result, even after long-term use, vibration and abnormal wear of the shaft grounding member 1E can be prevented, the contact state between the shaft grounding member 1E and the fixed member 75 and bearing 50 can be stabilized, and sufficient and stable conductivity can be ensured.

[0141] Furthermore, the force exerted by the flexible member 25 to restore its shape applies pressure to the annular portion 11E of the spring plate 10E of the shaft contact member 1E, as well as to the inner ring 52. Therefore, the fixing member 75 and the inner ring 52 can be securely fixed, making it possible to suppress the occurrence of rotational creep of the inner ring 52, and thereby suppressing vibrations and abnormal wear caused by rotational creep.

[0142] In particular, in a bearing unit 100E where the fixed member 75 is made of aluminum and the fixed member 75 and the inner ring 52 are made of different materials, the dimensional change due to the difference in thermal expansion coefficients between the fixed member 75 and the inner ring 52 is large, making creep and loosening of the fit more likely to occur. Therefore, an increase in the pressing force of the flexible member 25 at the mounting portion of the shaft contact member 1E becomes more significant.

[0143] Furthermore, similar to the sixth embodiment, the biasing force exerted by the spring plate 10E on the inner circumferential surface 65d of the rotating member 65 by the soft conductive member 20 is not very strong, so wear particles are less likely to be generated.

[0144] Similar to the sixth embodiment, the biasing force on the inner circumferential surface 65d of the rotating member 65 can be adjusted by appropriately setting the bending angle between the curved plate portion 13a and the first flat plate portion 13b in Figure 16(B). This further improves the effect of reducing the axial voltage between the rotating member 65 and the fixed member 75, and the effect of suppressing the generation of wear particles. Furthermore, the extension length of the curved plate portion 13a, the size of the soft conductive member 20, and the degree of curvature of the curved plate portion 13a can also be appropriately set, and by adjusting these, the aforementioned axial voltage can be reduced more stably.

[0145] Furthermore, in the seventh embodiment, the inner circumferential end surface 15E of the annular portion 11E and the spacer 30 are in contact with the fixing member 75, but a configuration in which they are not in contact with the fixing member 75 is also possible.

[0146] The annular portion 11E and the spacer 30 may be sandwiched between the inner ring 52 by the flange portion 76 or a conductive retaining member that replaces the flange portion 76. In that case, the current flowing through the annular portion 11E flows to the fixing member 75 via the inner ring 52 or the retaining member.

[0147] In addition, in the sixth and seventh embodiments, the number of connecting parts is not limited to one, but may be multiple. Furthermore, in the axial grounding members 1D and 1E, the area of ​​the elastic parts 13D and 13E can be freely designed, and the number and size of the connecting parts 12D and 12E can also be freely designed.

[0148] It should be noted that the present invention is not limited to the embodiments described above, and can be modified and improved as appropriate. In the above embodiment, the elastic portions 13A, 13B, and 13C of the spring plates 10A, 10B, and 10C are configured to bend toward the rotating ring side. However, they may also be formed flush with the annular portions 11A, 11B, and 11C without bending at the inner diameter end 12A, the outer diameter end 12B, and the elastic base portion 14C. For example, in the case of the shaft grounding member 1A for inner ring rotation shown in Figure 1, the annular portion 11A and the elastic portion 13A may be linearly continuous in cross-sectional view, as shown in Figure 18. Also, for example, in the case of the shaft grounding member 1B for outer ring rotation shown in Figure 4, the annular portion 11B and the elastic portion 13B may be linearly continuous in cross-sectional view, as shown in Figure 19. Furthermore, in the case of the shaft grounding member 1C shown in Figure 11, as shown in Figure 20, the annular portion 11C and the elastic portion 13C may be linearly continuous in cross-sectional view.

[0149] Therefore, in the bearing units 100A and 100C shown in Figures 21 and 23, when the annular portions 11A and 11C of the shaft grounding members 1A and 1C are sandwiched between the flange portion 71 of the housing 70 and the side surface of the outer ring 51, the elastic portions 13A and 13C of the shaft grounding members 1A and 1C elastically deform by the thickness of the soft conductive member 20, and the bending reaction force of the spring plates 10A and 10C causes the soft conductive member 20 to come into contact with the side surface 52a of the inner ring 52 and the side surface 60a of the shaft 60, respectively. Furthermore, in the bearing unit 100B shown in Figure 22, when the annular portion 11B of the shaft grounding member 1B is sandwiched between the flange portion 76 of the fixing member 75 and the side surface of the inner ring 52, the elastic portion 13B of the shaft grounding member 1B elastically deforms by the thickness of the soft conductive member 20, and the bending reaction force of the spring plate 10B causes the soft conductive member 20 to come into contact with the side surface 51a of the outer ring 51. This allows the same function as in the above embodiment to be achieved.

[0150] In this case, bending of the spring plates 10A, 10B, and 10C is unnecessary, so the shaft grounding members 1A, 1B, and 1C can be manufactured at a low cost, and the bonding of the spring plates 10A, 10B, and 10C to the soft conductive member 20 can be easily performed.

[0151] In all embodiments, there are no restrictions on the planar shape of the flexible conductive member 20. In addition to the sector shape shown in Figure 1(A), it may also be rectangular. It may also be made up of multiple small pieces.

[0152] Furthermore, the axial grounding member of the present invention can also be suitably used when only one of the following is required: prevention of electrolytic corrosion and suppression of electromagnetic noise generation.

[0153] In this embodiment, the flexible member is mounted on the same side of the annular portion as the surface to which the soft conductive member is attached. However, it may also be mounted on the side opposite to the surface to which the soft conductive member is attached, or on both sides. Furthermore, the flexible member does not need to be conductive as long as current flows from the annular portion to the housing.

[0154] Furthermore, when flexible members are attached to both sides of the annular portion, at least one of the flexible members is conductive. By attaching flexible members to both sides of the annular portion in this way, the restoring force of the flexible members is improved and the amount of deformation increases, thereby further enhancing the effects of the present invention. [Explanation of Symbols]

[0155] 1A, 1B, 1C, 1D, 1E Axle grounding member 10A, 10B, 10C, 10D, 10E Spring Plate 11A, 11B, 11C, 11D, 11E Annular section 12A Inner diameter end 12B Outer diameter end 12C Inner circumference end 12D,12E connection part 13A, 13B, 13C, 13D, 13E Elastic part 13a Curved plate part 13b 1st flat plate part 14C elastic base 15A,15C,15D Outer edge 15B, 15E Inner circumferential end face 16A, 16B, 17D, 18D Notches 16D Boundary 20 Flexible conductive material 21D bent part 25 Flexible material 30 Spacers 50 bearings 51 Outer ring 51a, 52a, 60a, 65a Side view 52 Inner Ring 53 Rolling element 54 Cage 60 shaft 60b,65b mating surface 60c,65c step surface 60d circumferential surface 62, 67, 71, 76 Flange section (Pressing part) 65 Rotating member 65d Inner surface 70 Housing G 7 5 Fixing members 80. Retaining member (retaining part) 99 Single component 100A, 100B, 100C, 100D, 100E Bearing Unit

Claims

1. A shaft grounding member that is mounted on a rolling bearing unit having a rolling bearing in which one raceway is a fixed wheel and the other raceway is a rotating wheel, A spring plate made of a thin sheet of conductive material is composed of an annular portion and at least one elastic portion that extends radially continuously from the annular portion, In the elastic portion, a soft conductive member is mounted on the surface facing the rotating wheel or the rotating member into which the rotating wheel is fitted, A conductive flexible member is attached to the side surface of the annular portion, In addition to being equipped, The soft conductive member is capable of contacting at least a portion of the surface of the rotating wheel, or at least a portion of the surface of the rotating member. The flexible member is compressed by being sandwiched between the fixing member to which the fixing ring is fixed, and the fixing ring, with a pressing portion provided integrally with or separately from the fixing member to which the fixing ring is fixed. A shaft grounding member for rolling bearings, characterized by the above.

2. The flexible member is attached to both sides of the annular portion, and the flexible member attached to at least one of the two sides is electrically conductive, as described in claim 1, for a rolling bearing shaft grounding member.

3. The shaft grounding member for a rolling bearing according to claim 1, characterized in that the flexible member is composed of at least one selected from a soft porous body selected from nonwoven fabric, woven fabric and sponge, and a resin-impregnated soft porous body.

4. The shaft grounding member for a rolling bearing according to claim 1, characterized in that the flexible member and the soft conductive member are a single member attached to the same side surface of the annular portion and the elastic portion.

5. The shaft grounding member for a rolling bearing according to claim 1, characterized in that the annular portion is electrically connected to the fixed ring or the fixed member.

6. The spring plate is composed of the annular portion and a plurality of elastic portions that extend radially in a continuous manner from the annular portion. The rolling bearing shaft grounding member according to claim 1, characterized in that the plurality of elastic parts are bent toward the rotating ring.

7. The spring plate is composed of the annular portion and a plurality of elastic portions that extend radially from the annular portion. The rolling bearing shaft grounding member according to claim 1, characterized in that the plurality of elastic portions are formed flush with the annular portion.

8. The rolling bearing comprises an inner ring rotation type in which the outer ring is the fixed ring and the inner ring is the rotating ring. A rolling bearing unit equipped with a rolling bearing shaft grounding member according to any one of claims 1 to 7, The outer ring is fixed to the fixing member, and the rotating member is fitted into the inner ring. A rolling bearing unit characterized in that the annular portion is clamped and compressed by the outer ring and a retaining portion provided integrally with or separately from the fixing member.

9. The rolling bearing comprises an outer ring rotation type in which the inner ring is the fixed ring and the outer ring is the rotating ring. A rolling bearing unit equipped with a rolling bearing shaft grounding member according to any one of claims 1 to 7, The outer ring is fitted onto the rotating member, and the inner ring is fixed to the stationary member. A rolling bearing unit characterized in that the annular portion is clamped and compressed by the inner ring and a retaining portion provided integrally with or separately from the fixing member.

10. The aforementioned rolling bearing is an inner-ring rotating type, in which the fixed ring is an outer ring fixed to the housing, and the rotating ring is an inner ring into which a shaft directly connected to the motor is fitted. The spring plate is composed of the annular portion and the elastic portion which extends from the inner circumferential end of the annular portion to the center of the annular portion, The soft conductive member is mounted on the side of the elastic portion facing the shaft and is capable of contacting the end face or side surface of the shaft. The shaft grounding member for rolling bearings according to claim 1, characterized in that...

11. The shaft grounding member for a rolling bearing according to claim 10, characterized in that the elastic portion of the spring plate is bent in the middle.

12. The shaft grounding member for a rolling bearing according to claim 10, characterized in that the elastic portion of the spring plate is formed flush with the annular portion.

13. The rolling bearing comprises an inner ring rotation type in which the outer ring is the fixed ring and the inner ring is the rotating ring. A rolling bearing unit equipped with a rolling bearing shaft grounding member according to any one of claims 10 to 12, The outer ring is fixed to the housing, and the shaft is fitted into the inner ring. A rolling bearing unit characterized in that the annular portion is held between the outer ring and a retaining portion provided integrally with or separately from the housing.

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