Axle ground member for rolling bearing and rolling bearing unit

Abstract

The present application provides a shaft grounding member for a rolling bearing and a rolling bearing unit to which the shaft grounding member is attached, which suppresses generation of abrasion powder from a conductive member or abrasion powder accompanying sliding contact of the conductive member with a mating member, and also suppresses temperature rise caused by damage and sliding of the mating member, and does not form new processing to the bearing, and in addition, the type of the bearing is not limited, and existing bearings can be dealt with. The shaft grounding member for a rolling bearing is provided with a spring plate composed of a circular ring portion and one or a plurality of elastic portions continuously extending radially from the circular ring portion, and a soft conductive member containing a lubricant in advance, attached to a surface of the elastic portion opposite to a rotating ring, and the soft conductive member can abut against a side surface of the rotating ring. In addition, the rolling bearing unit is provided with the shaft grounding member.

Description

Technical Field

[0001] The present invention relates to a rolling bearing shaft grounding member installed to suppress the occurrence of electrolytic corrosion or electromagnetic noise in the rolling bearing of a rolling bearing unit, and a rolling bearing unit equipped with the rolling bearing shaft grounding member. Background Technology

[0002] In recent years, the practical application of electric vehicles that use electric motors as a drive source, located inside or near the wheels, has been developing. Such drive motors are generally called in-wheel motors. Structurally, an in-wheel motor typically has a stator fixed to the motor housing, and a rotor positioned radially spaced from the inner diameter of the stator, forming what is known as an internal rotor type motor. Furthermore, considering motor performance and control capabilities, brushless direct current (DC) motors driven by inverters are often used as the driving method for in-wheel motors.

[0003] In drive systems using converters, a potential difference arises between the stator and rotor due to parasitic capacitance and other factors. This potential difference generates shaft voltage / shaft current. If this shaft current flows through the rolling bearings supporting the rotor, a phenomenon known as "electrolytic corrosion" occurs, damaging the rolling bearings. Specifically, current flows locally through the contact area between the rolling surfaces of the outer / inner rings of the rolling bearing and the rotating parts, causing the raceway or rotating surfaces to melt and become uneven. This not only roughens the rolling surfaces and rotating parts of the bearing, contributing to noise and vibration, but excessive electrolytic corrosion can also shorten the bearing's lifespan.

[0004] To prevent electrolytic corrosion of rolling bearings, a solution of clamping conductive components is also adopted. For example, in Patent Document 1 and Patent Document 2, a solution is proposed that consists of a contact body for electrical communication with the rotor of the motor, an elastic body for pressing the contact body towards the rotor side, and a housing part for accommodating the contact body and the elastic body. The housing part is provided in the motor housing and is electrically connected to the motor stator through the motor housing.

[0005] Furthermore, Patent Document 3 proposes a grounding device that brings the tip of a broom-shaped conductive fiber into contact with the outer peripheral surface of a rotating shaft.

[0006] Furthermore, Patent Document 4 proposes an electro-erosion prevention device that bends an annular seat portion that is in contact with the end face of the outer ring of the bearing into a wave shape. Using an elastic conductor having a contact piece extending from the inside of the annular seat portion and in contact with the center of the end face of the rotating shaft, the device conducts electricity by pressing the surface of the annular seat portion through the cover wall of the bearing housing while the annular seat portion coincides with the end face of the outer ring of the bearing housing and the contact piece abuts against the center of the end face of the rotating shaft that is in contact with the inner ring of the bearing.

[0007] In addition, Patent Document 5 proposes to house a rod-shaped conductive brush in a support hole provided in either of the two track rings, and to apply force to the tip of the conductive brush toward the other track ring side by means of an elastic member so that it slides into contact, thereby making the two track rings electrically connected.

[0008] Patent document 6 proposes that the top end of a carbon wire shaft grounding brush be positioned to abut against an extended shaft to remove the shaft voltage generated by the shaft by grounding, thereby preventing electrolytic corrosion in the bearing.

[0009] Furthermore, for bearings, there is a need to address electromagnetic noise caused by electromagnetic interference, and various devices for suppressing the generation of electromagnetic noise have been proposed. For example, Patent Document 7 proposes a method of accommodating a conductive rod-shaped carbon brush between an inner ring and a metal ring, and using a spring to apply force to the tip of the carbon brush mounted on the metal ring towards the inner ring to make it slide into contact. This imparts conductivity to the conductive bearing, and allows the current flowing through the conductive bearing to flow out of the system via the metal ring and the brush section, thereby eliminating electromagnetic noise.

[0010] Patent document 8 discloses a conductive device that suppresses the formation of an oil film between a conductive rubber lip attached to a rotating shaft and a metal housing by centrifugal force, or controls the thickness of the oil film, thereby releasing electromagnetic noise. By suppressing the formation of the oil film or reducing its thickness, the resistance of the oil film can be reduced, and electromagnetic noise can be released from the rotating shaft and housing.

[0011] Patent document 9 proposes that by rotating a conductive rotating body between the outer and inner rings in a state of cutting through the oil film, the charge channel is ensured, thereby significantly reducing the impedance between the outer and inner rings or the bearing as a whole, thus improving the electromagnetic noise prevention effect and the electro-erosion prevention effect.

[0012] Patent document 10 proposes an electromagnetic noise suppression device that electrically connects the metal casing of the motor and the rotating shaft inside the motor through a conductive part such as a sliding contact member, thereby releasing the electromagnetic noise caused by the rotating shaft to the metal motor casing grounded to the vehicle body.

[0013] Existing technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 2011-135720 Patent Document 2: Japanese Patent Application Publication No. 2011-135722 Patent Document 3: Japanese Patent Application Publication No. 2020-127257 Patent Document 4: Japanese Patent Application Publication No. 2002-146568 Patent Document 5: Japanese Utility Model Application Publication No. 4-8820 Patent Document 6: Japanese Patent Application Publication No. 2017-060401 Patent Document 7: Japanese Patent Application Publication No. 2024-130948 Patent Document 8: Japanese Patent Application Publication No. 2023-018214 Patent Document 9: Japanese Patent Application Publication No. 2022-139252 Patent Document 10: Japanese Patent Application Publication No. 2000-244180 However, in the technology described in any of the aforementioned patent documents, there is a possibility that the wear powder generated from the conductive component becomes a contaminant of the lubricant or grease composition sealed in for lubrication, thereby affecting the rolling or rotating surfaces. Furthermore, it may sometimes damage the mating parts of the conductive component, thus generating its wear powder.

[0014] In a more detailed description, in Patent Documents 1 and 2, the contact body, elastomer, and housing are metal components that slide into contact with each other as the motor vibrates, thereby generating metal powder. Furthermore, the contact body, elastomer, and housing need to be housed within the motor housing, requiring space for this purpose.

[0015] Furthermore, in Patent Document 3, the tip of the broom-shaped conductive fiber is brought into contact with the outer peripheral surface of the rotating shaft. However, compared to the case where only the tip of the broom-shaped conductive fiber is brought into contact with the rotating shaft, the contact area is larger. Therefore, the broom-shaped conductive fiber contacts the outer peripheral surface of the rotating shaft while in a flexed state. That is, the tip of the broom-shaped conductive fiber is brought into contact with the outer peripheral surface of the rotating shaft under a relatively strong pressure, thus generating abrasive powder. At the same time, the outer peripheral surface of the rotating shaft, which is the mating part of the broom-shaped conductive fiber, is also damaged.

[0016] Furthermore, in Patent Document 4, both the elastic conductor and the rotating shaft are metal, and metal powder will be generated due to sliding contact between them. At the same time, the end face of the mating part of the elastic conductor, namely the rotating shaft, will be damaged.

[0017] Furthermore, in Patent Document 5, the tip of the rod-shaped conductive brush contacts the other side's track ring under applied force, thus generating abrasive powder from the conductive brush. Simultaneously, the track ring, the mating component of the conductive brush, is also damaged. Furthermore, support holes need to be formed in the track ring to accommodate the conductive brush and the elastic member, placing a significant load on the track ring.

[0018] In Patent Document 6, the tip of the carbon filament shaft-mounted brush is positioned to abut against the extension shaft, which generates abrasive powder from the shaft-mounted brush. Simultaneously, the mating component of the shaft-mounted brush, the extension shaft, also suffers damage.

[0019] Furthermore, in the bearings shown in Patent Documents 1 to 9, frictional heat is sometimes generated due to the sliding contact between the conductive components and the mating parts during use, thereby reducing the durability of the bearing. In addition, with the increasing performance of motors in recent years, the circumferential speed of rotating components has also increased, thus requiring further suppression of temperature rise.

[0020] Furthermore, regarding Patent Document 10, a wear-resistant component was selected as the sliding contact component, but the effect of reducing wear was insufficient. Summary of the Invention

[0021] Therefore, the object of the present invention is to provide a shaft grounding member and a rolling bearing unit equipped with the shaft grounding member, which suppresses the generation of wear powder from the conductive member or wear powder accompanying the sliding contact between the conductive member and the mating part, as well as suppresses the temperature rise caused by sliding, and also suppresses damage to the mating part, without requiring new processing to the bearing. Furthermore, there are no restrictions on the type of bearing, it can be used with existing bearings, saves space and has a low-cost structure.

[0022] The above-mentioned objective of the present invention will be achieved by the following configuration [1] to

[14] .

[0023] [1] A shaft grounding member for a rolling bearing, mounted on a rolling bearing unit, the rolling bearing unit having a rolling bearing, wherein one of the track rings of the rolling bearing is a fixed track ring and the other track ring is a rotating track ring, characterized in that, The shaft grounding component for the rolling bearing includes: A spring plate comprises an annular portion and at least one elastic portion extending radially continuously from the annular portion, and the spring plate is formed of a thin sheet of conductive material; and A soft conductive component is mounted in the elastic part on the surface opposite to the rotating ring or a rotating component that is fitted into the rotating ring. The soft conductive component contains a pre-lubricant and can abut against at least a portion of the surface of the rotating ring or at least a portion of the surface of the rotating component.

[0024] [2] The shaft grounding member for rolling bearings according to [1], wherein the shaft grounding member is used in a dry environment where there is no flow of lubricating fluid such as lubricating oil, and the lubricant is non-volatile.

[0025] [3] The rolling bearing shaft grounding member according to [1] or [2] is characterized in that the soft conductive member is composed of at least one material selected from the following: resin impregnation of nonwoven fabric, nonwoven fabric, resin impregnation of fabric, fabric, resin impregnation of soft porous material and soft porous material.

[0026] [4] The bearing shaft grounding member according to any one of [1] to [3], characterized in that, The spring plate is composed of the annular portion and a plurality of elastic portions extending radially from the annular portion. The soft conductive component is mounted in the elastic part on the surface opposite to the rotating ring. The soft conductive component can abut against the side of the rotating ring.

[0027] [5] The bearing shaft grounding member according to any one of [1] to [3], characterized in that, The spring plate is composed of the annular portion and a plurality of elastic portions extending radially from the annular portion. The soft conductive component is mounted in the elastic part on the surface opposite to the rotating component. The soft conductive component can abut against the side of the rotating component.

[0028] [6] The rolling bearing shaft grounding member according to any one of [1] to [5] is characterized in that the annular portion is pressed against the side of the fixed ring when a spacer is sandwiched in between.

[0029] [7] The rolling bearing shaft grounding member according to any one of [1] to [6], characterized in that, The spring plate is composed of the annular portion and a plurality of elastic portions extending radially from the annular portion. The multiple elastic sections bend toward one side of the rotating ring.

[0030] [8] A shaft grounding member for a rolling bearing according to any one of [1] to [6], characterized in that, The spring plate is composed of the annular portion and a plurality of elastic portions extending radially from the annular portion. The multiple elastic portions are formed flush with the annular portion.

[0031] [9] A rolling bearing unit, characterized in that it comprises: A rolling bearing, wherein one raceway is a fixed raceway and the other raceway is a rotating raceway. The rolling bearing unit is equipped with a rolling bearing shaft grounding member as described in any one of [1] to [8].

[0032]

[10] The bearing shaft grounding member according to any one of [1] to [3], characterized in that, The rolling bearing is an inner-ring rotating type where the fixed ring is an outer ring fixed to the housing, and the rotating ring is an inner ring rotating type with an inner ring embedded in the shaft directly connected to the motor. The spring plate is composed of the annular portion and the elastic portion extending continuously from the inner circumferential end of the annular portion toward the center of the annular portion. The soft conductive member is mounted on the side of the elastic part opposite to the rolling bearing. The soft conductive component can abut against the side of the shaft.

[0033]

[11] The rolling bearing shaft grounding member according to

[10] is characterized in that the annular portion is pressed against the side of the outer ring when a spacer is sandwiched in between.

[0034]

[12] The rolling bearing shaft grounding member according to

[10] is characterized in that the elastic portion of the spring plate is bent toward the side of the shaft.

[0035]

[13] The rolling bearing shaft grounding member according to

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

[0036]

[14] A rolling bearing unit, characterized in that it comprises: An inner-ring rotating type rolling bearing, wherein the outer ring of the rolling bearing is fixed to the housing, and a shaft directly connected to the motor is embedded in the inner ring of the rolling bearing. The rolling bearing unit is equipped with a rolling bearing shaft grounding member as described in any one of

[10] to

[13] .

[0037] Invention Effects The shaft grounding member of the present invention comprises a soft conductive member pre-containing lubricant mounted on the elastic portion of a spring plate, wherein the soft conductive member abuts against at least a portion of the surface of a rotating ring or rotating member. The force exerted by the soft conductive member on the rotating ring or rotating member by the spring plate is not too strong, thus minimizing the generation of wear powder. Furthermore, since the soft conductive member is made of a soft material, damage to the rotating ring, which is the mating component, is also reduced. The soft conductive member does not contain lubricant, thereby suppressing frictional heat caused by sliding contact.

[0038] Furthermore, no machining is required on the rolling bearings, and there are no restrictions on the types of rolling bearings; it can be used with existing rolling bearings, thus offering extremely high versatility. Moreover, the spring plate is a thin plate, minimizing the increase in space required for the bearing unit to be installed.

[0039] The bearing unit of the present invention is equipped with the shaft grounding member of the present invention, thus suppressing the generation of wear powder, damage to mating parts, and the reduction in durability caused by frictional heat. It is also highly versatile and does not increase space requirements. Attached Figure Description

[0040] Figure 1 An example is shown of the shaft grounding member, which is a first embodiment of the present invention, applied to an inner ring rotating type bearing unit. Figure 1 (A) is its top view. Figure 1 (B) is Figure 1 Sectional view AA of (A), Figure 1 (C) represents Figure 1 Enlarged view of the curved portion of the annular part and the elastic part in (B).

[0041] Figure 2 It means to Figure 1 The cross-sectional view shown is of the shaft grounding member being installed in the bearing unit.

[0042] Figure 3 It indicates that it is assembled. Figure 1 A cross-sectional view of an example of a bearing unit of a shaft grounding component.

[0043] Figure 4 An example is shown of a shaft grounding member, as a second embodiment of the present invention, applied to a bearing unit on the outer ring rotating side. Figure 4 (A) is its top view. Figure 4 (B) is Figure 4 AA section view of (A).

[0044] Figure 5 It means to Figure 4 The cross-sectional view shown is of the shaft grounding member being installed in the bearing unit.

[0045] Figure 6 It indicates that it is equipped with Figure 4 A cross-sectional view of an example of a bearing unit of a shaft grounding component.

[0046] Figure 7 This is a cross-sectional view showing an example of an inner ring rotating type bearing unit fitted with a shaft grounding member according to the third embodiment of the present invention.

[0047] Figure 8 This is a cross-sectional view showing an example of an inner ring rotating type bearing unit fitted with another shaft grounding member according to the third embodiment of the present invention.

[0048] Figure 9This is a cross-sectional view showing an example of a bearing unit with an outer ring rotating type bearing unit fitted with a shaft grounding member according to the fourth embodiment of the present invention.

[0049] Figure 10 This is a cross-sectional view showing an example of an outer ring rotating type bearing unit fitted with another shaft grounding member according to the fourth embodiment of the present invention.

[0050] Figure 11 An example of a shaft grounding member according to the fifth embodiment of the present invention is shown. Figure 11 (A) is its top view. Figure 11 (B) is Figure 11 Sectional view AA of (A), Figure 11 (C) represents Figure 11 Enlarged view of the bent portion of the elastic part in (B).

[0051] Figure 12 It means to Figure 11 The cross-sectional view shown is of the shaft grounding member being installed in the bearing unit.

[0052] Figure 13 It indicates that it is assembled. Figure 11 A cross-sectional view of an example of a bearing unit of a shaft grounding component.

[0053] Figure 14 The shaft grounding member of the modified embodiment of the present invention is related to Figure 1 (B) is the corresponding sectional view.

[0054] Figure 15 The shaft grounding member of the modified embodiment of the present invention is related to Figure 4 (B) is the corresponding sectional view.

[0055] Figure 16 The shaft grounding member of the modified embodiment of the present invention is related to Figure 11 (B) is the corresponding sectional view.

[0056] Figure 17 It indicates that it is assembled. Figure 14 A cross-sectional view of an example of a bearing unit of a shaft grounding component.

[0057] Figure 18 It indicates that it is assembled. Figure 15 A cross-sectional view of an example of a bearing unit of a shaft grounding component.

[0058] Figure 19 It indicates that it is assembled. Figure 16 A cross-sectional view of an example of a bearing unit of a shaft grounding component.

[0059] Figure 20This is a schematic diagram illustrating an example of a device used in conductivity and temperature evaluation.

[0060] Figure 21 An example of an axis grounding member for conductivity and temperature evaluation is shown. Figure 21 (A) is its top view. Figure 21 (B) is its rear view.

[0061] Explanation of reference numerals in the attached figures: 1A, 1B, 1C: Shaft grounding components; 10A, 10B, 10C: Spring plates; 11A, 11B, 11C: Circular portions; 13A, 13B, 13C: Elastic portions; 14B: Inner circumferential end face; 15A, 15C: Outer circumferential end faces; 16A, 16B: Notches; 20: Soft conductive components; 30: Spacers; 50: Rolling bearings; 51: Outer ring; 51a, 52a, 60a, 65a: Side surface; 52: Inner ring; 53: Rotating body; 55: Seal; 60: Shaft; 60b, 65b: Fitting surfaces; 60c, 65c: Stepped surfaces; 62, 67, 71, 76: Flanges; 65: Rotating component; 70: Housing; 75: Fixing component; 80: Pressing component; 100A, 100B, 100C: Bearing units; 200: Measuring device; CP: Conductive path. Detailed Implementation

[0062] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that the present invention is not limited to the embodiments described below, and can be implemented by any modifications without departing from the spirit of the present invention. Hereinafter, "shaft grounding member for rolling bearing" will be referred to simply as "shaft grounding member", and "rolling bearing unit" will be referred to simply as "bearing unit".

[0063] (First embodiment: Shaft grounding member and bearing unit for inner ring rotation) Figure 1 An example of an shaft grounding member of the present invention applied when the rotating ring is the inner ring is shown. Figure 1 (A) is its top view. Figure 1 (B) is Figure 1 Sectional view AA of (A), Figure 1 (C) represents Figure 1 An enlarged view of the curved portion of the annular part and the elastic part in (B). Furthermore, Figure 2 It means to Figure 1 The cross-sectional view shown is of the shaft grounding member being installed in the bearing unit. Figure 3 It indicates that it is assembled. Figure 1 A cross-sectional view of an example of a bearing unit of a shaft grounding component.

[0064] like Figure 1 As shown, the shaft grounding member 1A for inner ring rotation includes a spring plate 10A, which is composed of an annular portion 11A and multiple 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 elastic portions 13A and the bent portion of the annular portion 11A to maintain the bent state of the elastic portions 13A.

[0065] The spring plate 10A is a thin plate made entirely of conductive materials such as metal. When the conductive material is metal, stainless steel is preferred for reasons such as ease of processing and less rusting.

[0066] A flexible conductive member 20 is attached to the curved side of each elastic part 13A, and the spring plate 10A and the flexible conductive member 20 together form an axial grounding member 1A. The flexible conductive member 20 contains a lubricant in advance and is attached to the elastic part 13A with an adhesive or the like.

[0067] Soft conductive components and lubricants will be described in detail later.

[0068] like Figure 2 and Figure 3 As shown, the bearing unit 100A of the first embodiment includes a rolling bearing and is equipped with... Figure 1 The shaft grounding member 1A is shown. The rolling bearing 50 has: an outer ring 51 forming one track ring; an inner ring 52 forming the other track ring; and a plurality of rotating bodies (balls) 53, which are rotatably held between the outer ring 51 and the inner ring 52 by a retainer 54. The rotating bodies 53 rotate smoothly by a bearing lubricant such as a lubricating oil or grease composition. The bearing lubricant is sealed by a seal 55. Here, the rotating ring is the inner ring 52, and a shaft 60 (not shown) directly connected to a motor is embedded in the inner diameter side of the inner ring 52. In addition, the outer ring 51 is a fixed ring, fixed to the housing 70.

[0069] The flexible conductive member 20 is mounted on the surface of the elastic part 13A opposite to the inner ring (rotating ring) 52 (right side in the figure), and is mounted on the bearing unit 100A with the bent side of the flexible conductive member 20 facing the inner ring 52.

[0070] like Figure 3As shown, the bearing unit 100A is used in the following state: the annular portion 11A of the shaft grounding member 1A is pressed against the side of the outer ring 51 by the conductive pressing member 80 with the conductive spacer 30 sandwiched between them. Therefore, the outer diameter side of the outer ring 51 and the outer peripheral end face 15A of the annular portion 11A in the spring plate 10A are fixed in contact with the housing 70, and the soft conductive member 20 can abut against the side surface 52a of the inner ring 52. The spring plate 10A is formed of a thin plate and has elasticity; therefore, by pressing the annular portion 11A of the shaft grounding member 1A towards the outer ring 51, the elastic force generated by the pressing acts on the elastic portion 13A, thereby... Figure 1 The bending angle θ shown in (C) increases as the object is pushed away. Accompanying this, in Figure 2 In the process, the portion of the soft conductive member 20 that is away from the inner ring 52 on the side 52a will also move toward the rolling bearing 50 side, and the soft conductive member 20 as a whole will come into contact with the side 52a of the inner ring 52.

[0071] The spacer 30 only needs to be set to a thickness that takes into account the pressing amount of the spring plate 10A, the thickness of the soft conductive member 20, etc. In addition, the annular portion 11A of the shaft grounding member 1A can directly abut against the side of the outer ring 51 without the spacer 30.

[0072] The flexible conductive component 20 is a component in which a conductive material is mixed into or supported in a flexible matrix material. The flexible matrix material can be porous materials such as paper, cloth, and nonwoven fabric, or resin sheets. Furthermore, commercially available materials such as "conductive sheets" can also be used as the flexible conductive component. Examples of conductive materials include metal fibers, pulverized materials, and powders such as silver, copper, gold, aluminum, and stainless steel, or conductive carbon fibers, pulverized materials, and powders. Preferably, it is composed of at least one material selected from resin-impregnated nonwoven fabrics, resin-impregnated nonwoven fabrics, resin-impregnated fabrics, fabrics, resin-impregnated soft porous materials such as sponges, and soft porous materials such as sponges.

[0073] The types of lubricants contained in the flexible conductive component 20 can include lubricating oil and lubricating grease. There are no particular limitations as long as the lubricant is non-volatile in the operating environment of the flexible conductive component 20; commonly used lubricants for bearings can be used. The lubricant contained in the flexible conductive component 20 can be the same as or different from the lubricant in the bearing. However, if different lubricants are mixed, the disassembly of a deteriorated bearing unit will make processing difficult; therefore, it is preferable to use the same lubricant.

[0074] Regarding the viscosity of the lubricant, there is no limitation as long as it can suppress outflow from the soft conductive member 20 in a static state. This is because in the first embodiment, the soft conductive member 20 does not rotate and does not generate outflow caused by centrifugal force. Therefore, if outflow can be suppressed in a static state, it can withstand long-term use.

[0075] Specifically, lubricants can be mineral oils, synthetic oils, greases containing mineral oils or synthetic oils and thickeners, or mixtures thereof. Examples of mineral oils include paraffinic mineral oils and naphthenic mineral oils. Examples of synthetic oils include hydrocarbon oils, aromatic oils, ester oils, and ether oils. Examples of thickeners include urea compounds and metal soaps.

[0076] Furthermore, there are no particular limitations on the method of containing lubricant in the soft conductive component 20. For example, a method of coating the soft conductive component 20 with lubricant or impregnating it with lubricant can be selected.

[0077] In the inner ring rotating type bearing unit 100A without the shaft grounding member assembled, normally, current from the motor flows through the shaft 60 to the inner ring 52, energizing the rotating body 53 and the outer ring 51, causing electrolytic corrosion of the rolling bearing 50. In contrast, in the first embodiment, the soft conductive member 20 in the shaft grounding member 1A is mounted to the housing 70 in a manner that abuts against the side surface 52a of the inner ring 52. Furthermore, the annular portion 11A of the spring plate 10A is electrically connected to the side surface of the outer ring 51 via a conductive spacer 30, and is also electrically connected to the conductive pressing member 80.

[0078] Therefore, in the first embodiment, current from the motor (not shown) driving the shaft 60 flows to the inner ring 52. Then, the current flows through the inner ring 52 from the soft conductive member 20 to the elastic portion 13A and the annular portion 11A of the spring plate 10A, and then via the outer peripheral end face 15A of the annular portion 11A, the pressing member 80, the spacer 30, and the outer ring 51 to the grounded housing 70. By grounding the shaft 60, which is a rotating member, and the housing 70, which is a stationary member, in this way, the bearing interior is not energized, and the shaft voltage, representing the potential difference between the rotating and stationary members, is significantly reduced. Therefore, electrolytic corrosion of the rolling bearing 50 can be prevented, and electromagnetic noise can be reduced.

[0079] It should be noted that the contact area between the outer ring 51 and the housing 70 is relatively large. Therefore, the current flowing through the outer ring 51 will flow to the housing 70 instead of through the rotating body 53.

[0080] Furthermore, 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 will not be damaged, and the reduction in the rotational torque of the inner ring 52 can be suppressed. Moreover, the force applied to the side surface of the inner ring 52 by the soft conductive member 20 generated by the spring plate 10A is not too strong, and the soft conductive member 20 contains a lubricant, thus suppressing the generation of wear powder.

[0081] It should be noted that, assuming the lubricant filling the bearing around the rotating body 53 is sealed by the seal 55, the soft conductive member 20 is used in a dry environment where there is no flow of lubricating oil or other lubricating fluid. In the first embodiment, by simply using the shaft grounding member 1A having a soft conductive member 20 pre-containing lubricant, the temperature rise caused by the sliding between the soft conductive member 20 and the bearing 50 in a dry environment can be suppressed, thereby improving the durability of the shaft grounding member 1A.

[0082] When a porous material is selected as the soft conductive member 20 in this embodiment of the invention, the pore structure of the porous material is controlled, thereby utilizing the surface tension of the lubricant to maintain its content. Furthermore, when the surface lubricant decreases, the internal lubricant moves to the surface due to capillary action. As a result, a lubricating film is always formed on the side surface of the inner ring 52 that abuts against the soft conductive member 20, suppressing the generation of frictional heat and further reducing the temperature rise caused by sliding.

[0083] It should be noted that in the first embodiment, the outer peripheral end face 15A of the annular portion 11A and the spacer 30 abut against the housing 70, but they may not abut against the housing 70, but instead be clamped between the annular portion 11A and the outer ring 51 by the pressing member 80. In this case, the current flowing through the annular portion 11A will flow to the housing 70 via the outer ring 51 and the pressing member 80.

[0084] In addition, the annular portion 11A of the shaft grounding member 1A may be pressed directly against the side of the outer ring 51 and fixed to the housing 70 without the pressing member 80, provided that a conductive spacer 30 is sandwiched between it.

[0085] In addition, such as Figure 1 As shown in (C), the bending angle θ between the annular portion 11A and the elastic portion 13A can be appropriately set according to the length (L) of the elastic portion 13A and the size of the flexible conductive member 20, so that the flexible conductive member 20 abuts against the side surface 52a of the inner ring 52 of the rolling bearing 50 when it is mounted to the bearing unit 100A. The force applied by the flexible conductive member 20 to the side surface 52a of the inner ring 52 of the rolling bearing 50 can be adjusted by the bending angle θ. The applied force can be increased by decreasing the bending angle θ, and vice versa.

[0086] By adjusting the pressing force of the pressing member 80 on the outer ring 51, the contact area between the soft conductive member 20 of the shaft grounding member 1A and the side surface 52a of the inner ring 52 of the rolling bearing 50 changes. Therefore, by increasing the contact area between the soft conductive member 20 and the side surface 52a of the inner ring 52, electrolytic corrosion of the rolling bearing 50 can be prevented more effectively, electromagnetic noise can be reduced, and temperature rise caused by friction can be suppressed.

[0087] (Second embodiment: Shaft grounding member and bearing unit for outer ring rotation) In the first embodiment, the case where the inner ring 52 of the rolling bearing 50 is a rotating ring was described. In the second embodiment, the bearing unit where the outer ring 51 is a rotating ring was described. Figure 4 This is a diagram showing the shaft grounding component used for the rotation of the outer ring. Figure 4 (A) is its top view. Figure 4 (B) is Figure 4 Sectional view AA of (A). Furthermore, Figure 5 It means to Figure 4 The cross-sectional view shown is of the shaft grounding member being installed in the bearing unit. Figure 6 It indicates that it is assembled. Figure 4 A cross-sectional view of an example of a bearing unit of a shaft grounding component.

[0088] In the bearing unit of the second embodiment, the same reference numerals are used to mark the same components as in the first embodiment, and their detailed descriptions are omitted or simplified.

[0089] like Figure 4 As shown, the shaft grounding member 1B for outer ring rotation includes a spring plate 10B, which is composed of an annular portion 11B and multiple elastic portions 13B that are bent at the outer diameter end 12B of the annular portion 11B and extend radially outward from the annular portion 11B. Figure 5 As shown, the elastic portion 13B is bent toward the right side of the figure so as to face the outer ring 51 of the rolling bearing 50 when it is 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 and the annular portion 11B.

[0090] On the side of each elastic part 13B opposite to the outer ring 51 of the rolling bearing 50, a soft conductive member 20 containing a pre-lubricant is attached by an adhesive or the like, and the spring plate 10B and the soft conductive member 20 constitute the shaft grounding member 1B.

[0091] like Figure 5 and Figure 6 As shown, the bearing unit 100B of the second embodiment includes a rolling bearing 50 and is equipped with... Figure 4The shaft grounding member 1B is shown. The inner ring 52 of the rolling bearing 50 is fixed to the fixing member 75, and a rotating member 65 is mounted on the outer ring 51. Figure 5 As shown, the soft conductive member 20 is mounted on the surface of the elastic part 13B opposite to the outer ring (rotating ring) 51 (right side in the figure), and is mounted on the bearing unit 100B with the bent side of the soft conductive member 20 facing the outer ring 51.

[0092] In addition, such as Figure 6 As shown, the bearing unit 100B is used in the following state: the annular portion 11B of the shaft grounding member 1B is pressed against the side of the inner ring 52 by the pressing member 80 with the conductive spacer 30 sandwiched between them. Therefore, the inner diameter side of the inner ring 52 and the inner peripheral end face of the annular portion 11B in the spring plate 10B are fixed in abutting against the fixing member 75, and the soft conductive member 20 can abut against the side of the outer ring 51.

[0093] In the second embodiment, current from a motor (not shown) driving the rotating member 65 flows to the outer ring 51. Then, the current flows through the outer ring 51 from the soft conductive member 20 to the elastic portion 13B and the annular portion 11B of the spring plate 10B, and then through the inner peripheral end face 14B of the annular portion 11B, the pressing member 80, the spacer 30, and the inner ring 52 to the grounded fixed member 75. By grounding the rotating member 65 and the fixed member 75 in this way, the bearing interior is not energized, significantly reducing the shaft voltage, which is the potential difference between the rotating member and the fixed member. Therefore, electrolytic corrosion of the rolling bearing 50 can be prevented, and electromagnetic noise can be reduced.

[0094] Furthermore, similar to the first embodiment, the force applied by the soft conductive member 20 generated by the spring plate 10B to the side of the outer ring 51 is not too strong, and the soft conductive member 20 contains lubricant, so it is not easy to generate wear powder. Moreover, since the soft conductive member 20 contains lubricant in advance, the temperature rise caused by the sliding between the soft conductive member 20 and the outer ring 51 can be suppressed.

[0095] It should be noted that by adjusting the pressing force of the pressing member 80 on the outer ring 51 to increase the contact area between the soft conductive member 20 and the side surface 51a of the outer ring 51, the electrolytic corrosion of the rolling bearing 50 can be prevented more effectively, and the temperature rise caused by friction can be suppressed.

[0096] In addition, in this embodiment, the annular portion 11B of the shaft grounding member 1B may directly abut against the side of the inner ring 52 without the spacer 30.

[0097] Furthermore, the inner peripheral end face 14B of the annular portion 11B and the spacer 30 can abut against the fixing member 75, or they can be clamped between the inner ring 52 by the pressing member 80 without abutting against the fixing member 75.

[0098] (Third embodiment: Shaft grounding member and bearing unit for inner ring rotation) Similarly to the first embodiment, Figure 7 The diagram shows a case where the shaft grounding member 1A is mounted on a bearing unit with the inner ring of the rotating ring. In the bearing unit of 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.

[0099] In the third embodiment, a stepped surface 60c with a smaller diameter than the mating surface 60b of the inner ring 52 is formed on the shaft 60, which serves as a rotating member for fitting the inner ring 52. A soft conductive member 20 pre-lubricated with lubricant is mounted on the surface of the elastic portion 13A that is axially opposite to the shaft 60, specifically on the side surface 60a between the mating surface 60b and the stepped surface 60c of the inner ring 52. Furthermore, the shaft grounding member 1A elastically deforms the elastic portion 13A and mounts it to the housing 70. In addition, the annular portion 11A of the spring plate 10A and the spacer 30 are sandwiched between the flange portion 71, which is configured to protrude toward the inner diameter side of the housing 70, and the outer ring 51.

[0100] like Figure 7 As shown, in this inner ring rotating type bearing unit 100A, the soft conductive member 20 of the shaft grounding member 1A is mounted to the housing 70 in such a way that it abuts against the side surface 60a of the shaft 60. As a result, the annular portion 11A of the spring plate 10A is electrically connected to the side surface of the outer ring 51 when the conductive spacer 30 is sandwiched in between, and is also electrically connected to the end face of the flange portion 71 of the housing 70.

[0101] exist Figure 7 In the bearing unit 100A shown, current from the shaft 60 flows through the side 60a of the shaft 60 from the soft conductive member 20 to the elastic portion 13A and the annular portion 11A of the spring plate 10A. Then, the current flows through the spacer 30 and the outer ring 51 to the housing 70, or through the outer peripheral end face 15A of the annular portion 11A to the grounded housing 70. By grounding the shaft 60, which is a rotating member, and the housing 70, which is a stationary member, in this way, no current is conducted inside the bearing, and the shaft voltage, which is the potential difference between the rotating and stationary members, can be significantly reduced. Therefore, electrolytic corrosion of the rolling bearing 50 can be prevented, and electromagnetic noise can be reduced.

[0102] Furthermore, similar to the first embodiment, the force applied by the soft conductive member 20 generated by the spring plate 10A to the side of the shaft 60 is not too strong, and the soft conductive member 20 contains lubricant, so it is not easy to generate wear powder. Moreover, since the soft conductive member 20 contains lubricant in advance, the temperature rise caused by the sliding between the soft conductive member 20 and the shaft 60 can be suppressed.

[0103] It should be noted that, as Figure 8 As shown, in this embodiment, a flange portion 62 protruding from the mating surface 60b toward the outer diameter side may also be provided on the shaft 60, so that the soft conductive member 20 abuts against the side surface 60a of the flange portion 62.

[0104] In particular, Figure 7 In the bearing unit 100A shown, the position where the soft conductive member 20 contacts the side surface 60a of the shaft 60 is relatively smaller than that of the bearing unit 100A shown. Figure 3 The diameter of the position where it contacts the side 52a of the inner ring 52 is smaller, thus reducing the circumferential speed of the side 60a of the shaft 60 and further suppressing the generation of wear powder and dragging loss.

[0105] The third embodiment differs from the first embodiment in that the shaft grounding member 1A does not contact the side 52a of the inner ring 52, thus increasing the design freedom of rolling bearings such as the mounting of the retaining ring.

[0106] (Fourth embodiment: Shaft grounding member and bearing unit for outer ring rotation) Similarly to the second embodiment, Figure 9 The diagram shows a case where the shaft grounding member 1B is mounted on a bearing unit with an outer ring 51. In the bearing unit of 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.

[0107] In the fourth embodiment, a stepped surface 65c with a diameter larger than the mating surface 65b on which the outer ring 51 is fitted is formed on the rotating member 65. A soft conductive member 20 pre-lubricated with lubricant is mounted on the surface of the elastic portion 13B that is axially opposite to the rotating member 65. Specifically, it is mounted on the surface opposite to the side surface 65a between the mating surface 65b and the stepped surface 65c on which the outer ring 51 is fitted. Therefore, the soft conductive member 20 can abut against the side surface 65a of the rotating member 65.

[0108] like Figure 9As shown, in the outer ring rotating type bearing unit 100B, the soft conductive member 20 of the shaft grounding member 1B is mounted to the fixing member 75 in such a way that it abuts against the side surface 65a of the rotating member 65. As a result, the annular portion 11B of the spring plate 10B is electrically connected to the side surface of the inner ring 52 via the conductive spacer 30, and is also electrically connected to the end face of the flange portion 76 of the fixing member 75.

[0109] exist Figure 9 In the bearing unit 100B shown, current from a motor (not shown) driving the rotating member 65 flows through the side 65a of the rotating member 65, from the soft conductive member 20 through the elastic portion 13B and the annular portion 11B of the spring plate 10B, to the inner circumferential end face 14B of the annular portion 11B. Then, the current flows through the spacer 30 and the inner ring 52 to the grounded fixed member 75, or directly to the fixed member 75. By grounding the rotating member 65 and the fixed member 75 in this way, the bearing interior is not energized, significantly reducing the shaft voltage, which is the potential difference between the rotating member and the fixed member. Therefore, electrolytic corrosion of the rolling bearing 50 can be prevented, and electromagnetic noise can be reduced.

[0110] Furthermore, similar to the first embodiment, the force applied by the soft conductive member 20 generated by the spring plate 10B to the side of the rotating member 65 is not too strong, and the soft conductive member 20 contains lubricant, so it is not easy to generate wear powder. Moreover, since the soft conductive member 20 contains lubricant in advance, the temperature rise caused by the sliding between the soft conductive member 20 and the rotating member 65 can be suppressed.

[0111] It should be noted that, as Figure 10 As shown, in this embodiment, a flange portion 67 protruding from the mating surface 65b toward the inner diameter side can be provided on the rotating member 65, so that the soft conductive member 20 abuts against the side surface 65a of the flange portion 67.

[0112] In particular, Figure 10 In the bearing unit 100B shown, the position where the soft conductive member 20 contacts the side surface 65a of the rotating member 65 is, for example... Figure 6 The small diameter of the contact point with the side 51a of the outer ring 51 shown can reduce the circumferential speed of the side 65a of the rotating member 65, and further suppress the generation of wear powder and dragging loss.

[0113] Furthermore, unlike the second embodiment, the fourth embodiment does not have the shaft grounding member 1B in contact with the side 51a of the outer ring 51, thus increasing the design freedom of rolling bearings such as the mounting of the retaining ring.

[0114] (Fifth embodiment: A shaft grounding member and bearing unit for rotating an inner ring with an elastic section) Figure 11An example of a shaft grounding member according to the fifth embodiment of the present invention is shown. Figure 11 (A) is its top view. Figure 11 (B) is Figure 11 Sectional view AA of (A), Figure 11 (C) represents Figure 11 An enlarged view of the curved portion of the annular part and the elastic part in (B). Furthermore, Figure 12 It means to Figure 11 The cross-sectional view shown is of the shaft grounding member being installed in the bearing unit. Figure 13 It indicates that it is assembled. Figure 11 A cross-sectional view of an example of a bearing unit of a shaft grounding component.

[0115] In the bearing unit of the fifth embodiment, the same reference numerals are used to mark the same components as in the first embodiment, and their detailed descriptions are omitted or simplified.

[0116] like Figure 11 As shown, the shaft grounding member 1C includes a spring plate 10C, which is bent from an annular portion 11C and an inner circumferential end 12C of the annular portion 11C and extends continuously toward the radial center from the annular portion 11C. An elastic portion 13C is bent starting from an elastic base 14C. A soft conductive member 20 pre-lubricated with a flexible adhesive is attached to the bent side of the elastic portion 13C using an adhesive or the like. The shaft grounding member 1C is constituted by the spring plate 10C and the soft conductive member 20.

[0117] like Figure 12 As shown, the shaft grounding member 1C is mounted to the bearing unit 100C with the bent side surface of the elastic part 13C (right side in the figure) facing the side surface 60a of the shaft 60 into which the inner ring 52 of the rolling bearing 50 is embedded. It should be noted that the side surface 60a of the shaft 60 refers to the surface of the shaft 60 that is orthogonal to the axial direction.

[0118] In addition, such as Figure 13 As shown, the bearing unit 100C is used in the following state: the annular portion 11C of the shaft grounding member 1C is pressed against the side of the outer ring 51 by the pressing member 80 with the spacer 30 sandwiched between them. Therefore, the soft conductive member 20 can abut against the side 60a of the shaft 60. Thus, the annular portion 11C of the spring plate 10C is electrically connected to the side of the outer ring 51 via the conductive spacer 30, and is also electrically connected to the housing 70.

[0119] In the fifth embodiment, current from the motor (not shown) of the drive 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 through the outer peripheral end face 15C of the annular portion 11C, the pressing member 80, the spacer 30, and the outer ring 51 to the grounded housing 70. By grounding the shaft 60, which is a rotating member, and the housing 70, which is a stationary member, in this way, the bearing interior is not energized, and the shaft voltage, which is the potential difference between the rotating member and the stationary member, can be significantly reduced. Therefore, electrolytic corrosion of the rolling bearing 50 can be prevented, and electromagnetic noise can be reduced.

[0120] Furthermore, similar to the first embodiment, the force applied by the soft conductive member 20 generated by the spring plate 10C to the side of the shaft 60 is not too strong, and the soft conductive member 20 contains lubricant, so it is not easy to generate wear powder. Moreover, since the soft conductive member 20 contains lubricant in advance, the temperature rise caused by the sliding between the soft conductive member 20 and the shaft 60 can be suppressed.

[0121] Furthermore, in the fifth embodiment, the outer peripheral end face 15C of the annular portion 11C and the spacer 30 abut against the housing 70, or they may not abut against the housing 70, but are held between the annular portion 11C and the outer ring 51 by the pressing member 80. In this case, the current flowing through the annular portion 11C flows to the housing 70 via the outer ring 51 and the pressing member 80. It should be noted that the contact area between the outer ring 51 and the housing 70 is large; therefore, the current flowing through the outer ring 51 flows to the housing 70 and does not pass through the rotating body 53.

[0122] Furthermore, in the bearing unit 100C, the soft conductive member 20 abuts against the side surface 60a of the shaft 60, and compared to the case where the soft conductive member 20 contacts the side surface of the inner ring 52, the circumferential speed is further reduced. Therefore, compared to other embodiments, the generation of abrasive powder and dragging wear can be further suppressed. It should be noted that the circumferential speed is lowest near the center of the shaft; therefore, it is preferable that the soft conductive member 20 abuts near the center of the shaft.

[0123] It should be noted that the present invention is not limited to the above-described embodiments, and can be appropriately modified and improved.

[0124] In the above embodiment, the elastic portions 13A, 13B, and 13C of the spring plates 10A, 10B, and 10C are configured to be bent toward one side of the rotating ring. However, it is also possible that the inner diameter end 12A, outer diameter end 12B, and elastic base 14C are not bent, and are instead formed flush with the annular portions 11A, 11B, and 11C. For example, it is also possible that... Figure 1 In the case of the shaft grounding member 1A for inner ring rotation shown, as Figure 14As shown, the annular portion 11A and the elastic portion 13A appear as a continuous straight line when viewed in cross-section. Furthermore, for example, it is also possible that... Figure 4 In the case of the shaft grounding member 1B for outer ring rotation shown, as Figure 15 As shown, the annular portion 11B and the elastic portion 13B appear as a continuous straight line when viewed in cross-section. Furthermore, for example, it is also possible that... Figure 11 In the case of the shaft grounding member 1C shown, such as Figure 16 As shown, the annular portion 11C and the elastic portion 13C appear as a continuous straight line when viewed in cross-section.

[0125] Therefore, in Figure 17 and Figure 19 In the bearing units 100A and 100C shown, when the annular portions 11A and 11C of the shaft grounding members 1A and 1C are clamped 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 will elastically deform in accordance with the thickness of the soft conductive member 20. Through the bending reaction force of the spring plates 10A and 10C, the soft conductive member 20 abuts against the side surface 52a of the inner ring 52 and the side surface 60a of the shaft 60, respectively. Furthermore, in Figure 18 In the bearing unit 100B shown, when the annular portion 11B of the shaft grounding member 1B is clamped 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 will elastically deform in accordance with the thickness of the soft conductive member 20. Through the bending reaction force of the spring plate 10B, the soft conductive member 20 abuts against the side surface 51a of the outer ring 51. Thus, the same function as in the above embodiment can be achieved.

[0126] In this case, bending processing of spring plates 10A, 10B, and 10C is not required, so the shaft grounding components 1A, 1B, and 1C can be manufactured at a low cost. In addition, the bonding of spring plates 10A, 10B, and 10C to the soft conductive component 20 can be easily performed.

[0127] It should be noted that, in all embodiments, the planar shape of the flexible conductive member 20 is not limited. Except... Figure 1 In addition to the sector shape shown in (A), it can also be a rectangle. Furthermore, it can also be multiple small pieces.

[0128] Furthermore, the shaft grounding member of the present invention may also be appropriately used when only one of preventing electrolytic corrosion and suppressing electromagnetic noise is achieved.

[0129] [Example] To confirm the effectiveness of the present invention, a rolling bearing unit with a configuration substantially the same as that of the first embodiment was assembled in a measuring device and tested. Furthermore, tests were conducted using a rolling bearing shaft grounding member of the inventive example in which the soft conductive member was pre-impregnated with lubricant, and a rolling bearing shaft grounding member of the comparative example in which the soft conductive member did not contain lubricant. It should be noted that in the inventive example, a lubricant obtained by applying transmission oil to the soft conductive member was used as the lubricant.

[0130] <Measuring Apparatus> Reference Figure 20 The configuration of the measuring device 200 used for evaluating the conductivity of the shaft grounding member and measuring the temperature of the soft conductive member 20 is described.

[0131] In the measuring device 200, the inner ring (rotating ring) 52 of the rolling bearing 50 is fitted into the shaft (rotating member) 60 connected to the motor 91. The configuration of the rolling bearing 50 is the same as described in the first embodiment. Figure 3 The inner ring rotation shown has the same structure, therefore, in Figure 20 In the middle, to and Figure 3 The same components shown are labeled with the same reference numerals. The outer ring (fixed ring) 51 of the rolling bearing 50 is fixed to the inner diameter side of the housing (fixed component) 70.

[0132] The shaft grounding member 1A and the spacer 30 are mounted and clamped between the rolling bearing 50 and the pressing member 80. Furthermore, the pressing member 80 is subjected to a load in the direction of the shaft grounding member 1A by means of the piston 93 mounted on the cylinder 92, thereby fixing the shaft grounding member 1A and the spacer 30.

[0133] An insulated coupling 94 is mounted on shaft 60. Piston 93 and part of housing 70 are made of insulating material. A rotating body 53 formed of an insulator is disposed between the inner ring 52 and outer ring 51 of bearing 50. Thus, in order to evaluate the conductivity of shaft grounding member 1A, the conductive path other than shaft grounding member 1A is cut off. It should be noted that grease is filled inside the bearing, which is sealed by a seal (not shown), as the bearing lubricant. It is assumed that the soft conductive member 20 is used in a dry environment without the flow of lubricating oil or other lubricating fluid.

[0134] Used in temperature measurement Figure 21 The shown is a shaft grounding member 1A. In the shaft grounding member 1A, a temperature indicating tape 90 for temperature measurement is adhered to the side of the elastic part 13A opposite to the side where the flexible conductive member 20 is attached. The temperature indicating tape 90 is a temperature indicating tape that irreversibly changes color according to the temperature change of the adhered surface. Thus, the temperature of the shaft grounding member can be measured by visual inspection alone.

[0135] (Evaluation of conductivity) The following describes a method for evaluating the conductivity of a commercially available LCR (inductance-capacitance-resistance) meter 95. One conductive cable 98a of the LCR meter 95 is connected to a commercially available conductive brush 96 configured to contact the shaft 60. The other conductive cable 98b of the LCR meter 95 is connected to a terminal 97 that contacts the housing 70. Thus, as... Figure 20 As shown by the dashed line, a conductive path CP is formed, extending from the conductive brush 96 (entry point) through the shaft 60, inner ring 52, soft conductive member 20 (made of porous material), spring plate 10A, and housing 70 to the terminal 97 (exit point). The resistance between the conductive brush 96 and the terminal 97 is then measured using an LCR meter to evaluate whether the shaft grounding member 1A can maintain sufficient conductivity.

[0136] In addition, in this measurement, the conditions were set as follows: the diameter of shaft 60 is 30mm, the rotation speed is 3500rpm, the inner diameter of housing 70 is 62mm, the LCR instrument is an AC constant current power supply with a current value of 30mA.

[0137] The results of the temperature and resistance measurements of the shaft grounding member 1A are shown in Table 1 below. It should be noted that in Table 1, the resistance value of the comparative example is set to 1.0, and the resistance value of the invention example is shown as a relative value. As shown in Table 1 above, in the inventive example, by including a lubricant in the soft conductive member 20 formed of a porous material, a lubricating film is formed on the side of the inner ring (rotating ring) 52 that abuts against the soft conductive member 20, which suppresses the temperature rise during sliding, thereby achieving a temperature of 80°C. Furthermore, when the resistance value of the comparative example is set to 1.0, the resistance value in the inventive example is 2.4.

[0138] (Evaluation of measurement results) As an evaluation criterion for the measurement results, a resistance value less than 10.0 and a temperature less than 100°C when the resistance value of the comparative example is set to 1.0 will be judged as having good mechanical properties.

[0139] When the resistance of the shaft grounding member is significantly lower than that of the rolling bearing, the current flowing from the motor 91 flows from the inner ring (rotating ring) 52 of the rolling bearing 50 to the shaft grounding member 1A, thus preventing electrolytic corrosion of the rolling bearing 50 and suppressing the generation of electromagnetic noise. When the comparative example is set to 1.0, the resistance of the rolling bearing is approximately 1000 ohms. Therefore, if the resistance of the shaft grounding member is less than 10.0 ohms, it can be determined that it is a very low value.

[0140] In the soft conductive component 20 used in this invention, sometimes a portion of it contains organic materials, so thermal degradation is an important factor when judging its durability. Moreover, the relationship between durability (lifetime) and temperature can mostly be expressed by Arrhenius's law, which is represented by the following equation (1). The activation energy of the thermal degradation reaction of organic materials near 100°C is approximately 10 kcal to 30 kcal. Therefore, when assuming the activation energy to be 10 kcal and using the Arrhenius formula to calculate the lifetime of soft porous materials, the lifetime at 80°C is 5.9 times longer than that at 130°C.

[0141] Therefore, if the temperature of the soft conductive component is less than 100°C, it can be determined that the lifespan of the shaft grounding component is sufficient, and a bearing unit with excellent durability is obtained.

[0142] As shown above, the temperature and resistance values ​​measured in the invention examples both meet the evaluation criteria. Therefore, while maintaining sufficient conductivity as a shaft grounding member, it can suppress electromagnetic noise, reduce the rise in sliding temperature, and improve durability.

Claims

1. A shaft grounding member for a rolling bearing, mounted on a rolling bearing unit, the rolling bearing unit comprising a rolling bearing, wherein one track ring of the rolling bearing is a fixed track ring and the other track ring is a rotating track ring, characterized in that, The shaft grounding component for the rolling bearing includes: A spring plate comprises an annular portion and at least one elastic portion extending radially continuously from the annular portion, and the spring plate is formed of a thin sheet of conductive material; and A soft conductive component is mounted in the elastic part on the surface opposite to the rotating ring or a rotating component that is fitted into the rotating ring. The soft conductive component contains a pre-lubricant and can abut against at least a portion of the surface of the rotating ring or at least a portion of the surface of the rotating component.

2. The shaft grounding member for rolling bearings according to claim 1, wherein, The shaft grounding component is used in a dry environment, and the lubricant is non-volatile.

3. The shaft grounding member for rolling bearings according to claim 1, characterized in that, The soft conductive component is made of at least one material selected from the following: resin impregnation of nonwoven fabric, nonwoven fabric, resin impregnation of fabric, fabric, resin impregnation of soft porous material, and soft porous material.

4. The shaft grounding member for rolling bearings according to claim 1, characterized in that, The spring plate is composed of the annular portion and a plurality of elastic portions extending radially from the annular portion. The soft conductive component is mounted in the elastic part on the surface opposite to the rotating ring. The soft conductive component can abut against the side of the rotating ring.

5. The shaft grounding member for rolling bearings according to claim 1, characterized in that, The spring plate is composed of the annular portion and a plurality of elastic portions extending radially from the annular portion. The soft conductive component is mounted in the elastic part on the surface opposite to the rotating component. The soft conductive component can abut against the side of the rotating component.

6. The shaft grounding member for rolling bearings according to claim 1, characterized in that, The annular portion is pressed against the side of the retaining ring when a spacer is sandwiched in between.

7. The shaft grounding member for rolling bearings according to claim 1, characterized in that, The spring plate is composed of the annular portion and a plurality of elastic portions extending radially from the annular portion. The multiple elastic sections bend toward one side of the rotating ring.

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

9. A rolling bearing unit, characterized in that, have: A rolling bearing, wherein one raceway is a fixed raceway and the other raceway is a rotating raceway. The rolling bearing unit is equipped with a rolling bearing shaft grounding member as described in any one of claims 1 to 8.

10. The shaft grounding member for rolling bearings according to claim 1, characterized in that, The rolling bearing is an inner-ring rotating type where the fixed ring is an outer ring fixed to the housing, and the rotating ring is an inner ring rotating type with an inner ring embedded in the shaft directly connected to the motor. The spring plate is composed of the annular portion and the elastic portion extending continuously from the inner circumferential end of the annular portion toward the center of the annular portion. The soft conductive member is mounted on the side of the elastic part opposite to the rolling bearing. The soft conductive component can abut against the side of the shaft.

11. The shaft grounding member for rolling bearings according to claim 10, characterized in that, The annular portion is pressed against the side of the outer ring when a spacer is sandwiched in between.

12. The shaft grounding member for rolling bearings according to claim 10, characterized in that, The elastic portion of the spring plate bends laterally toward the side of the shaft.

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

14. A rolling bearing unit, characterized in that, have: An inner-ring rotating type rolling bearing, wherein the outer ring of the rolling bearing is fixed to the housing, and a shaft directly connected to the motor is embedded in the inner ring of the rolling bearing. The rolling bearing unit is equipped with a rolling bearing shaft grounding member as described in any one of claims 10 to 13.

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