Shaft grounding member for rolling bearing and rolling bearing unit

Abstract

The invention provides a shaft grounding member for a rolling bearing and a rolling bearing unit. A shaft grounding member for a rolling bearing is provided with: a spring plate comprising an annular part and an elastic part continuously extending from the inner peripheral end of the annular part to the center of the annular part, the spring plate being formed of a thin plate made of a conductive material; and a soft conductive member attached to a surface of the elastic portion facing the rolling bearing, the soft conductive member being capable of contacting an end surface of the shaft. The spring plate is provided with a plurality of curved sections, each of which is provided so as to be curved in the axial direction at a portion of the annular section facing the side surface of the outer ring, and which applies a pressing force to the outer ring by means of self-deformation.

Description

Technical Field

[0001] The present invention relates to a rolling bearing shaft grounding member installed to prevent 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 and shaft current. If this shaft current flows through the rolling bearings supporting the rotor, it causes damage known as "electrolytic corrosion." 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 can be 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 toward 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 surface of the annular seat portion is pressed by the cover wall of the bearing housing to conduct electricity 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 set to abut against an extended shaft, so that the shaft voltage generated by the shaft is grounded and removed, 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 electromagnetic noise have been proposed. For example, Patent Document 7 proposes a method where a conductive rod-shaped carbon brush is housed between an inner ring and a metal ring. A spring applies force to the tip of the carbon brush mounted on the metal ring, causing it to slide into contact with the inner ring. This imparts conductivity to the conductive bearing, and the current flowing through the conductive bearing flows 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 avoiding 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 uses a conductive part such as a sliding contact member to electrically connect the metal casing of the motor and the rotating shaft inside the motor, thereby releasing the electromagnetic noise caused by the rotating shaft to the metal casing of the motor that is grounded to the vehicle body.

[0013] Existing technical documents

[0014] 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 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

[0015] 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 lubricating oil or grease composition sealed in for lubrication, thereby causing damage to the rolling or rotating surfaces. Furthermore, it may sometimes damage the mating parts of the conductive component, thus generating its wear powder.

[0016] Specifically, 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.

[0017] 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.

[0018] 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.

[0019] 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 wear 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.

[0020] In Patent Document 6, the tip of the carbon filament shaft-mounted brush is positioned to abut against the extension shaft, thus generating wear powder from the shaft-mounted brush. Simultaneously, the mating component of the shaft-mounted brush, the extension shaft, is also damaged.

[0021] 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.

[0022] Furthermore, regarding Patent Document 10, a wear-resistant component was selected as the sliding contact component, but the effect of reducing wear was insufficient.

[0023] Furthermore, in the housing that serves as the outer ring for fitting the retaining ring, dissimilar materials different from bearing materials such as aluminum are sometimes used. In such cases, due to temperature changes, creep and loosening of the fit may occur between the retaining ring and the retaining member. In environments where such creep and loosening of the fit may occur, even when conductive members are used, it is necessary to ensure the electrical contact of the conductive members and obtain stable conductivity. Summary of the Invention

[0024] Therefore, the object of the present invention is to provide a shaft grounding member and a rolling bearing unit on which the shaft grounding member is mounted, which suppresses wear powder from the conductive member or wear powder generated by the sliding contact between the conductive member and the mating part, and also suppresses damage to the mating part. In addition, it can reliably ensure excellent conductivity, does not form new machining on the bearing, and is not limited to the type of bearing, can be used with existing bearings, and has a space-saving and low-cost structure.

[0025] The above-mentioned objective of the present invention will be achieved by the following configuration of the shaft grounding member for rolling bearings [1].

[0026] [1] A shaft grounding member for a rolling bearing, mounted on a rolling bearing unit having an inner rotating type rolling bearing, wherein the outer ring of the rolling bearing is fixed to a housing, and a shaft directly connected to a motor is embedded in the inner ring of the rolling bearing, characterized in that, The shaft grounding component includes: A spring plate, comprising an annular portion and an elastic portion extending continuously from the inner circumferential end of the annular portion towards the center of the annular portion, the spring plate being formed of a thin sheet of conductive material; and A soft conductive member is mounted on the surface of the elastic portion opposite to the rolling bearing, and... The soft conductive component can abut against the end face of the shaft. The spring plate has multiple curved portions, each of which is axially curved and located on the portion of the annular portion opposite to the side of the outer ring, and applies a pressing force to the outer ring by its own deformation.

[0027] Furthermore, preferred embodiments of the present invention for the shaft grounding member for rolling bearings relate to the following [2] to [9].

[0028] [2] According to the rolling bearing shaft grounding member described in [1], wherein, Each curved portion is a cut piece that is bent axially between a pair of notches cut from the outer periphery of the annular portion.

[0029] [3] According to the rolling bearing shaft grounding member described in [1], wherein, The plurality of curved portions have a cut piece that bends to one side of the axial direction and another cut piece that bends to the other side of the axial direction, the portion being the portion between a pair of notches that are cut from the outer periphery of the annular portion.

[0030] [4] According to the rolling bearing shaft grounding member described in [1], wherein, Each of the curved portions is a portion between a pair of notches cut from the outer periphery of the annular portion, or a folded-back piece that extends radially from the outer periphery of the annular portion and folds back axially.

[0031] [5] According to the rolling bearing shaft grounding member described in [1], wherein, The plurality of curved portions have a folded-back piece that folds back to one axial side and another folded-back piece that folds back to the other axial side, the portion being a portion between a pair of notches cut from the outer periphery of the annular portion or a portion extending radially from the outer periphery of the annular portion.

[0032] [6] A shaft grounding member for a rolling bearing according to any one of [1] to [5], wherein, The annular portion is pressed against the side of the outer ring with a spacer sandwiched in between.

[0033] [7] A shaft grounding member for a rolling bearing according to any one of [1] to [6], wherein, 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.

[0034] [8] A shaft grounding member for a rolling bearing according to any one of [1] to [7], wherein, The elastic portion of the spring plate bends midway.

[0035] [9] A shaft grounding member for a rolling bearing according to any one of [1] to [7], wherein, The elastic portion of the spring plate is formed flush with the annular portion.

[0036] The above-mentioned objective of the present invention will be achieved by the following configuration of the rolling bearing unit

[10] .

[0037]

[10] 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, and... The rolling bearing unit is equipped with a rolling bearing shaft grounding member as described in any one of [1] to [9].

[0038] It should be noted that in the following text, "shaft grounding member for rolling bearing" will be referred to as "shaft grounding member" only, and "rolling bearing unit" will be referred to as "bearing unit" only.

[0039] Invention Effects

[0040] In this invention, the spring plate with the axial grounding member has multiple bent portions. Each bent portion is axially bent at a portion of the annular portion opposite the side of the fixed ring. By deforming itself, it applies pressure between itself and the fixed ring. Therefore, without the need for additional components such as disc springs or wave springs, stable conductivity with the fixed ring and the housing can be ensured. Thus, it can suppress the decrease in conductivity caused by loosening of the axial grounding member or vibration, reduce the axial voltage (potential difference between the rotating and fixed members), prevent electrolytic corrosion of the rolling bearing, and avoid electromagnetic noise between the rotating and fixed members. Furthermore, it can prevent creep of the rolling bearing.

[0041] The shaft grounding member of the present invention is a member in which a soft conductive member, which is mounted on the elastic part of a spring plate, abuts against the end face of a shaft. The force applied by the spring plate to the end face of the shaft of the soft conductive member is not strong, and wear powder is not easily generated. Moreover, since the soft conductive member is made of soft material, the shaft, as a mating part, is less likely to be damaged.

[0042] Furthermore, no machining is required on the rolling bearings, and there are no restrictions on the types of rolling bearings that can be used; it is compatible with existing rolling bearings, thus offering extremely high versatility. Moreover, the spring plate is a thin plate, which minimizes the increase in space required for the bearing unit to be installed.

[0043] The bearing unit of the present invention is equipped with the shaft grounding member of the present invention, which suppresses the generation of wear powder and damage to mating parts, and is highly versatile without increasing space. Attached Figure Description

[0044] Figure 1 (A) is a perspective view showing an example of the shaft grounding member of the present invention. Figure 1 (B) is its main view.

[0045] Figure 2 (A) is Figure 1 Sectional view A-A of (B), Figure 2 (B) is an enlarged cross-sectional view showing the curved portion of the annular part and the elastic part.

[0046] Figure 3 These are other examples of slicing and corresponding to Figure 2 Enlarged sectional view of (B).

[0047] Figure 4 (A) means to Figure 1 The diagram shows the situation when the shaft grounding member is installed in the housing, and is a cross-sectional view showing the state before the cutting blade is pressed towards the outer ring side. Figure 4 (B) means Figure 1 The cross-sectional view shown shows the shaft grounding component being mounted on the bearing unit.

[0048] Figure 5 (A) is a perspective view showing a first modified example of the shaft grounding member according to an embodiment of the present invention. Figure 5 (B) is its main view.

[0049] Figure 6 yes Figure 5 (B) B-B sectional view.

[0050] Figure 7 It means to Figure 5 The diagram shows the situation when the shaft grounding component is installed in the housing. Figure 7 (A) is a cross-sectional view showing the state before the sliced ​​piece is pressed outwards. Figure 7 (B) is a cross-sectional view showing the state before the other slice is pressed towards the outer ring. Figure 7 (C) is a cross-sectional view showing the state in which one of the cutting pieces is pressed towards the outer ring side via the spacer, and the shaft grounding member is mounted on the bearing unit. Figure 7 (D) is a cross-sectional view showing the state in which the other cutting piece is pressed towards the outer ring side via the spacer and the shaft grounding member is mounted on the bearing unit.

[0051] Figure 8 (A) is a perspective view showing a second modified example of the shaft grounding member according to an embodiment of the present invention. Figure 8 (B) is its main view.

[0052] Figure 9 yes Figure 8 (B) C-C section view.

[0053] Figure 10 (A) means to Figure 8 and Figure 9 The diagram shows the situation when the shaft grounding member is installed in the housing, and is a cross-sectional view showing the state before the folded-back piece is pressed towards the outer ring side. Figure 10 (B) is a cross-sectional view showing the state in which the folded-back piece is pressed towards the outer ring side via the spacer and the shaft grounding member is mounted on the bearing unit.

[0054] Figure 11 This is a diagram illustrating a third modified example of the shaft grounding member according to an embodiment of the present invention, and it corresponds to... Figure 2 (A) is a sectional view.

[0055] Figure 12 It indicates that it is assembled. Figure 11 A cross-sectional view of an example of a bearing unit of a shaft grounding component.

[0056] Explanation of reference numerals in the attached figures:

[0057] 1: Shaft grounding member; 10: Spring plate; 11: Circular part; 12: Inner circumferential end; 13, 14: Elastic part; 17: Starting point; 18: Cutting piece (bending part); 20: Soft conductive member; 22: Fold-back piece (bending part); 30: Spacer; 50: Bearing; 51: Outer ring; 52: Inner ring; 52a, 60a: End face; 53: Rotating body; 54: Retainer; 60: Shaft; 70: Housing; 80: Pressing member; 100: Bearing unit. Detailed Implementation

[0058] 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 in any way without departing from the spirit of the present invention.

[0059] like Figure 1 As shown, the shaft grounding member 1 includes a spring plate 10, which is composed of an annular portion 11 and an elastic portion 13 extending from the inner circumferential end 12 of the annular portion 11 toward the center of the annular portion 11. Figure 2 and Figure 4 As shown, when the elastic part 13 is installed in the bearing unit 100, it bends to the right of the figure starting from the elastic base 14, in a manner that it approaches the end face 60a of the shaft 60 embedded in the inner ring 52 of the rolling bearing 50.

[0060] The spring plate 10 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.

[0061] At the top end of the elastic portion 13, i.e., at the center of the annular portion 11, a flexible conductive member 20 is attached to the side opposite to the end face 60a of the shaft 60 embedded in the rolling bearing 50. The shaft grounding member 1 is composed of a spring plate 10 and the flexible conductive member 20. The flexible conductive member 20 is attached to the elastic portion 13 with an adhesive.

[0062] As the flexible conductive member 20, a material in which a conductive material is mixed into or supported on a flexible matrix material can be used, or a commercially available material such as a "conductive sheet" can be used. Examples of flexible matrix materials include at least one selected from porous materials and resin-impregnated porous materials. Porous materials can include paper, cloth, nonwoven fabric, resin sheets, and sponges as flexible porous materials. Preferably, as the matrix material, at least one selected from the following materials is used: nonwoven fabric, woven fabric, and soft porous materials such as sponges, as well as resin-impregnated nonwoven fabrics, resin-impregnated woven fabrics, and resin-impregnated soft porous materials such as sponges. When a resin-impregnated material impregnated with resin in a porous material is used as the matrix material of the flexible conductive member 20, by coating its skeleton with resin, the flexible conductive member 20 can be improved to the desired strength while maintaining its flexible properties. Therefore, it is particularly preferred to use at least one of the following as the matrix material: resin impregnation material selected from nonwoven fabric, resin impregnation material of fabric, resin impregnation material of soft porous materials such as sponge.

[0063] It should be noted that, when using a porous resin impregnation material as the matrix material, a thermosetting resin is preferred as the resin impregnating the porous material. As a thermosetting resin, any varnish-like resin that can be impregnated into the matrix material and heat-cured is acceptable; examples include phenolic resin, modified phenolic resin, epoxy resin, modified epoxy resin, polyimide resin, silicone resin, polyester resin, polyurethane resin, and rubber resin.

[0064] As a conductive material incorporated into or supported on a soft matrix material, it is preferable to use at least one selected from metal fibers such as silver, copper, gold, aluminum, and stainless steel, as well as their pulverized or powdered forms, and conductive carbon fibers and their pulverized or powdered forms.

[0065] In addition, such as Figure 2As shown in (B), the bending angle θ1 of the annular portion 11 and the elastic portion 13 is appropriately set so that when mounted on the bearing unit 100, the flexible conductive member 20 abuts against the end face 60a of the shaft 60. The force applied by the flexible conductive member 20 to the end face 60a of the shaft 60 can be adjusted by the bending angle θ1. The applied force can be increased by decreasing the bending angle θ1, and vice versa.

[0066] It should be noted that there are no restrictions on the planar shape of the flexible conductive component 20, except... Figure 1 Besides the circle shown, it can also be a rectangle or multiple small pieces. The soft conductive member 20 is preferably abutted near the center of the shaft on the end face 60a of the shaft 60. The circumferential speed is lower near the center of the shaft, so it is less likely to generate wear powder.

[0067] Furthermore, multiple notches 16 are formed in the annular portion 11 from the outer periphery to the inner periphery, and a cut piece 18 (bent portion) bent from the starting point 17 is formed between adjacent notches 16. The cut piece 18 faces with its tip towards Figure 1 The paper of (B) is bent in the axial direction by tilting the far side, that is, bent in the opposite direction to the axial direction of the bending of the elastic part 13. The top of the cutter 18 is formed in a straight line and is located on the inner diameter side of the imaginary circle that does not form the cutter 18 and connects multiple arc-shaped parts with an outer arc shape.

[0068] It should be noted that, alternatively, slice 18 with the top facing upwards. Figure 1 The paper surface of (B) is bent axially in a way that is inclined to the front side. Furthermore, the cut sheet 18 is... Figure 1 There are four equally spaced sections in the middle, but there is no limit to the number. Moreover, as shown in the figure, multiple cut pieces 18 are formed alternately with multiple arc sections, but it is not limited to this, and they can also be formed all around the circumference of the annular portion 11.

[0069] like Figure 2 As shown in (B), the cutting angle θ2 of the cutting blade 18 relative to the annular portion 11 is not limited, and is appropriately set according to the applied force (pressing force) as the target. The applied force can be weakened by decreasing the cutting angle θ2, and conversely, the applied force can be increased by increasing the cutting angle θ2.

[0070] It should be noted that, in Figure 2 In (B), the cut sheet 18 is formed by a single bending process and is a flat surface, but it can also be, for example... Figure 3 As shown, the cross-section is formed by multiple (twice in the example shown) segmental bending.

[0071] Furthermore, such a spring plate 10 can be formed into a specified shape, for example, by blank processing, wire cutting, or laser processing, and then by bending processing performed by a press or the like, but the manufacturing method is not limited to this.

[0072] Figure 4 A bearing unit 100 with a shaft grounding member 1 configured as shown is illustrated. The rolling bearing 50 has a plurality of rotating elements (balls) 53 between an outer ring 51 and an inner ring 52. These rotating elements 53 are held in place by a retainer 54 and are lubricated by a combination of lubricating oil and grease. Here, the inner ring 52 is the rotating ring, into which a shaft 60 (not shown) is directly connected. The shaft 60 is inserted with its end face 60a flush with the end face 52a of the inner ring 52. The outer ring 51 is a fixed ring, fixed to a housing 70. It should be noted that the configuration of the rolling bearing 50 is not limited to this and other configurations are also possible.

[0073] like Figure 4 As shown in (A), when the shaft grounding member 1 is installed on the bearing unit 100, the conductive spacer 30 is pre-embedded into the inner diameter side of the housing 70, and then the shaft grounding member 1 is embedded into the inner diameter side of the housing 70. Afterwards, the conductive pressing member 80 is embedded into the inner diameter side of the housing 70, and the pressing member 80 is pressed towards the outer ring 51. Thus, the annular portion 11 of the shaft grounding member 1 is pressed against the side of the outer ring 51 through the conductive spacer 30. Here, the cutting piece 18 of the shaft grounding member 1 undergoes elastic deformation by the pressing member 80, therefore, an axial spring reaction force acts on the spacer 30 and the pressing member 80, resulting in an increased pressing force on the side 51a of the outer ring 51 through the spacer 30.

[0074] It should be noted that the spacer 30 only needs to be set to a thickness that takes into account the pressing amount of the spring plate 10, the thickness of the soft conductive member 20, etc. In addition, the annular portion 11 of the shaft grounding member 1 can directly abut against the side of the outer ring 51 without the spacer 30.

[0075] In the inner ring rotating type bearing unit 100 without the shaft grounding member 1 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 this invention, the soft conductive member 20 in the shaft grounding member 1 is mounted to the housing 70 in a manner that abuts against the end face 60a of the shaft 60. Furthermore, the annular portion 11 of the spring plate 10 is electrically connected to the side of the outer ring 51 via a conductive spacer 30, and is also electrically connected to the conductive pressing member 80.

[0076] Therefore, the current from shaft 60 flows from the soft conductive member 20 to the elastic part 13 and the annular part 11 of the spring plate 10, and then flows to the housing 70 via the cutting piece 18 of the annular part 11, the outer periphery of the arc portion of the annular part 11, the pressing member 80, the spacer 30, and the outer ring 51. It should be noted that the contact area between the outer ring 51 and the housing 70 is relatively large. Therefore, the current flowing to the outer ring 51 will flow to the housing 70 without passing through the rotating body 53.

[0077] Thus, the shaft grounding member 1 grounds the shaft 60, which is a rotating member, and the housing 70, which is a fixed member. Therefore, the bearing interior is not energized, and the shaft voltage, which is the potential difference between the rotating member and the fixed member, is significantly reduced. Therefore, electrolytic corrosion of the rolling bearing 50 can be prevented, and electromagnetic noise can be avoided between the shaft 60, which is a rotating member, and the housing 70, which is a fixed member.

[0078] In this embodiment, the outer periphery of the arcuate portion of the annular portion 11 and the spacer 30 abut against the housing 70. However, it is also possible that they do not abut against the housing 70, but are instead held between the annular portion 11 and the outer ring 51 by the pressing member 80. In this case, the current flowing through the annular portion 11 flows to the housing 70 via the outer ring 51 and the pressing member 80.

[0079] Furthermore, the end face 60a of the shaft 60 is in contact with the soft conductive member 20, so the end face 60a of the shaft 60 will not be damaged, and the reduction of the rotational torque of the shaft 60 can be suppressed.

[0080] When the matrix material of the soft conductive component 20 is porous, it exhibits oil absorption and retention properties. Therefore, during shaft rotation, oil easily drains from between adjacent spring plates 10, and an oil film is not easily formed. Consequently, it maintains good conductivity even when used in oil. It should be noted that by making the matrix material of the soft conductive component 20 porous, the coefficient of friction is suppressed even when used in environments other than oil, thus preventing a decrease in the rotational torque of the inner ring 52.

[0081] Furthermore, the spring plate 10 of the shaft grounding member 1 is a thin plate, which can greatly suppress the increase in space of the bearing unit 100. In addition, there are no restrictions on the rolling bearing 50, and no processing is required, so it can be used with existing rolling bearings, making it highly versatile.

[0082] As described above, by increasing the contact area between the soft conductive member 20 of the shaft grounding member 1 and the end face 60a of the shaft 60 of the rolling bearing 50, the shaft voltage between the rotating member and the stationary member can be stably reduced. The spring plate 10 is a thin, integrally bent elastic plate; therefore, by pressing the annular portion 11 of the shaft grounding member 1 towards the outer ring 51, the elastic force generated by the pressing acts on the elastic portion 13, thereby... Figure 2As shown in (B), the bending angle θ1 increases, causing the elastic part 13 to move towards the rolling bearing 50. Simultaneously, in Figure 4 In this process, the portion of the soft conductive member 20 that separates from the end face 60a of the shaft 60 also moves toward the rolling bearing 50, and the soft conductive member 20 is in almost complete contact with the end face 60a of the shaft 60. This improves the conductivity between the soft conductive member 20 and the inner ring 52, more effectively prevents electrolytic corrosion of the rolling bearing 50, and reduces electromagnetic noise.

[0083] Furthermore, the pressing force of the shaft grounding member 1 towards the outer ring 51 increases due to the cutting blade 18. Therefore, even if axial loosening occurs between the outer ring 51 and the housing 70, the shaft grounding member 1 remains fixed, and the annular portion 11 maintains electrical contact with the side of the outer ring 51 via the conductive spacer 30, as well as with the conductive pressing member 80. Thus, the aforementioned shaft voltage can be further and more stably reduced, achieving prevention of electrolytic corrosion and reduction of electromagnetic noise.

[0084] Furthermore, by using the cutting blade 18, the pressing pressure on the side of the outer ring 51 of the shaft grounding member 1 increases. Therefore, even if the fit between the outer ring 51 and the housing 70 becomes loose, the outer ring 51 can be fixed to the housing 70, thus suppressing the creep of the rolling bearing 50.

[0085] In particular, in the bearing unit 100 where the housing 70 is made of aluminum and the outer ring 51 is made of dissimilar materials, the dimensional changes caused by the difference in thermal expansion rates between the housing 70 and the outer ring 51 are large, making it more prone to creep and loosening of the fit. Therefore, it is more meaningful to increase the pressing pressure in the mounting part of the shaft grounding member 1 based on the cutting piece 18.

[0086] Furthermore, in rolling bearing units, disc springs, wave springs, etc. are generally used to suppress creep and axial loosening. However, since the shaft grounding member 1 has a cutting plate 18, disc springs, wave springs, etc. are not needed, and the cost of the rolling bearing unit can be reduced.

[0087] (First variation)

[0088] In the shaft grounding member 1 of the above embodiment, the cutting pieces 18 are all bent towards one axial direction, but it can also be, for example... Figure 5 and Figure 6 As shown, a cutting piece 18A that bends to one side of the axial direction and a cutting piece 18B that bends to the other side of the axial direction are alternately formed.

[0089] In this case, such as Figure 7As shown, when the annular portion 11 of the axial grounding member 1 is pressed against the side of the outer ring 51 through the conductive spacer 30 by the conductive pressing member 80, the cutting pieces 18A and 18B of the axial grounding member 1 undergo elastic deformation through the pressing member 80, and an axial spring reaction force is applied between the spacer 30 and the pressing member 80. Therefore, the pressing force against the side 51a of the outer ring 51 through the spacer 30 also increases, which can more reliably maintain the fixation of the axial grounding member 1, achieving the same effect as the above-described embodiment. It should be noted that the cutting pieces 18A and 18B are not limited to being formed alternately; either cutting piece 18A or cutting piece 18B can be formed at any position.

[0090] (Second variation)

[0091] In addition, such as Figure 8 and Figure 9 As shown, the shaft grounding member 1 may also have multiple folded-back pieces 22 (bending portions) to replace the multiple cutting pieces 18 that serve as force application points in the above embodiment.

[0092] Multiple notches 16 are formed in the annular portion 11 from the outer periphery to the inner periphery. Between adjacent notches 16, a folded-back piece 22 is formed, folding back from the starting point 17. The folded-back piece 22 faces with its top tip towards... Figure 8 The (B) is formed by folding back the paper surface on the far side, that is, folding back in the opposite direction to the axis of bending of the elastic part 13. The starting point 17 of the folded piece 22 is located on the inner diameter side of the imaginary circle that does not form the folded piece 22 and connects multiple arc-shaped parts with an outer periphery.

[0093] It should be noted that, alternatively, the folded-back piece 22 can be folded back with its top facing... Figure 8 The paper of (B) is formed by folding back the front side. Furthermore, the folded-back piece 22... Figure 8 There are four evenly spaced points in the middle, but there is no limit to the number. Moreover, as shown in the figure, multiple folded pieces 22 are formed alternately with multiple arc portions, but it is not limited to this and can also be formed all around the circumference of the annular portion 11.

[0094] like Figure 9 As shown, the bending angle θ3 of the folded piece 22 relative to the annular portion 11 is not limited, and is appropriately set according to the applied force (pressing force) as the target. The applied force can be weakened by decreasing the bending angle θ3, and the applied force can be increased by increasing the bending angle θ3.

[0095] In this case, such as Figure 10As shown, when the annular portion 11 of the axial grounding member 1 is pressed against the side of the outer ring 51 via the conductive spacer 30 by the conductive pressing member 80, the folded piece 22 of the axial grounding member 1 undergoes elastic deformation by the pressing member 80. Therefore, an axial spring reaction force is applied between the spacer 30 and the pressing member 80. As a result, the pressing force on the side 51a of the outer ring 51 via the spacer 30 also increases, which can more reliably maintain the fixation of the axial grounding member 1 and achieve the same effect as the above embodiment.

[0096] It should be noted that the folded piece 22 in the second modified example is formed by folding back the portion between adjacent notches 16, 16 in the axial direction, but it can also be formed by folding back the portion extending radially from the outer periphery of the annular portion 11 in the axial direction.

[0097] Furthermore, in the second modified example of the folding piece, similar to the cutting piece in the first modified example, it is also possible to adopt a configuration in which one part of the folding piece folds back to one side of the axial direction and the other part folds back to the other side of the axial direction. This part is the portion between a pair of notches 16, 16 that are cut from the outer periphery of the annular portion 11 or the portion that extends radially from the outer periphery of the annular portion 11.

[0098] It should be noted that the present invention is not limited to the above-described embodiments, and can be appropriately modified and improved.

[0099] For example, in the above embodiments, their first and second modifications, the elastic portion 13 of the spring plate 10 is configured to be bent midway, but it is also possible, as a third modification, that the elastic base 14 is not bent and is formed flush with the annular portion 11. That is, as... Figure 11 As shown, the annular portion 11 and the elastic portion 13 appear as a continuous straight line when viewed from the side. It should be noted that... Figure 2 In (A), the slicing piece 18 is formed in two opposing pairs of regions, but the position of the slicing piece 18 can be arbitrarily set. For example, it could also be, as Figure 11 As shown, the portion with the cut strip 18 is opposite to the portion without the cut strip 18.

[0100] Therefore, in Figure 12 In the bearing unit 100 shown, when the annular portion 11 of the shaft grounding member 1 is sandwiched between the flange portion 71 of the housing 70 and the side surface of the outer ring 51, the elastic portion 13 of the shaft grounding member 1 will elastically deform in accordance with the thickness of the soft conductive member 20. Through the bending reaction force of the spring plate 10, the soft conductive member 20 abuts against the end face 60a of the shaft 60. Thus, the same function as in the above embodiment can be performed.

[0101] In this case, bending of the spring plate 10 is not required, so the shaft grounding member 1 can be manufactured at a low cost. In addition, the bonding of the spring plate 10 to the soft conductive member 20 can be easily performed.

[0102] Furthermore, in this embodiment, the spring plate is configured to have one elastic portion extending toward the center of the annular portion, but it may also be configured to have multiple elastic portions extending radially toward the center of the annular portion.

[0103] Furthermore, the shaft grounding member of the present invention can also be appropriately used in cases where only one of preventing electrolytic corrosion and suppressing the occurrence of electromagnetic noise is achieved.

[0104] It should be noted that, when the primary goal is to prevent electro-erosion, the term "shaft grounding member" in this specification can be replaced with "electro-erosion prevention member," and the term "rolling bearing unit" can be replaced with "electro-erosion prevention rolling bearing unit." Specifically, as shown below.

[0105] (1) An anti-electro-erosion component for a rolling bearing, mounted on a rolling bearing unit having an inner rotating type rolling bearing, wherein the outer ring of the rolling bearing is fixed to a housing, and a shaft directly connected to a motor is embedded in the inner ring of the rolling bearing, characterized in that, The electro-erosion prevention component includes: A spring plate, comprising an annular portion and an elastic portion extending continuously from the inner circumferential end of the annular portion towards the center of the annular portion, the spring plate being formed of a thin sheet of conductive material; and A soft conductive component is mounted on the side of the elastic portion opposite to the rolling bearing. The soft conductive component can abut against the end face of the shaft. The spring plate has multiple curved portions, each of which is axially curved and located on the portion of the annular portion opposite to the side of the outer ring, and applies a pressing force to the outer ring by its own deformation.

[0106] (2) The anti-electro-erosion component for rolling bearings according to (1), wherein, Each curved portion is a cut piece that is bent axially between a pair of notches cut from the outer periphery of the annular portion.

[0107] (3) The anti-electro-erosion component for rolling bearings according to (1), wherein, The plurality of curved portions have a cut piece that bends to one side of the axial direction and another cut piece that bends to the other side of the axial direction, the portion being the portion between a pair of notches that are cut from the outer periphery of the annular portion.

[0108] (4) The anti-electro-erosion component for rolling bearings according to (1), wherein, Each of the curved portions is a portion between a pair of notches cut from the outer periphery of the annular portion, or a folded-back piece that extends radially from the outer periphery of the annular portion and folds back axially.

[0109] (5) The anti-electro-erosion component for rolling bearings according to (1), wherein, The plurality of curved portions have a folded-back piece that folds back to one axial side and another folded-back piece that folds back to the other axial side, the portion being a portion between a pair of notches cut from the outer periphery of the annular portion or a portion extending radially from the outer periphery of the annular portion.

[0110] (6) An anti-electro-erosion member for rolling bearings according to any one of (1) to (5), wherein, The annular portion is pressed against the side of the outer ring with a spacer sandwiched in between.

[0111] (7) An anti-electro-erosion member for rolling bearings according to any one of (1) to (6), wherein, 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.

[0112] (8) An anti-electro-erosion member for rolling bearings according to any one of (1) to (7), wherein, The elastic portion of the spring plate bends midway.

[0113] (9) An anti-electro-erosion member for rolling bearings according to any one of (1) to (7), wherein, The elastic portion of the spring plate is formed flush with the annular portion.

[0114] (10) A rolling bearing unit for preventing electro-erosion, characterized in that, The bearing is a rotary type with an inner ring. The outer ring of this bearing is fixed to the housing, and a shaft directly connected to the motor is embedded in the inner ring of the bearing. The anti-electro-erosion rolling bearing unit is equipped with an anti-electro-erosion component for rolling bearings as described in any one of (1) to (9).

[0115] In addition, when the main goal is to suppress electromagnetic noise, the "shaft grounding member" in this specification can be replaced with the "electromagnetic noise suppression member", and the "rolling bearing unit" can be replaced with the "electromagnetic noise suppression rolling bearing unit".

Claims

1. A shaft grounding member for a rolling bearing, mounted on a rolling bearing unit having a rolling bearing of the inner ring type, the outer ring of the rolling bearing being fixed to a housing, and a shaft directly connected to a motor being embedded in the inner ring of the rolling bearing, characterized in that, The shaft grounding component includes: A spring plate comprises an annular portion and an elastic portion extending continuously from the inner circumferential end of the annular portion toward the center of the annular portion, and the spring plate is formed of a thin sheet of conductive material; and A soft conductive member is mounted on the surface of the elastic portion opposite to the rolling bearing, and... The soft conductive component can abut against the end face of the shaft. The spring plate has multiple curved portions, each of which is axially curved and located on the portion of the annular portion opposite to the side of the outer ring, and applies a pressing force to the outer ring by its own deformation.

2. The shaft grounding member for rolling bearings according to claim 1, wherein, Each curved portion is a cut piece that is bent axially between a pair of notches cut from the outer periphery of the annular portion.

3. The shaft grounding member for rolling bearings according to claim 1, wherein, The plurality of curved portions have a cut piece that bends to one side of the axial direction and another cut piece that bends to the other side of the axial direction, the portion being the portion between a pair of notches that are cut from the outer periphery of the annular portion.

4. The shaft grounding member for rolling bearings according to claim 1, wherein, Each of the curved portions is a portion between a pair of notches cut from the outer periphery of the annular portion, or a folded-back piece extending radially from the outer periphery of the annular portion and folded back axially.

5. The shaft grounding member for rolling bearings according to claim 1, wherein, The plurality of curved portions have a folded-back piece that folds back to one axial side and another folded-back piece that folds back to the other axial side, the portion being a portion between a pair of notches cut from the outer periphery of the annular portion or a portion extending radially from the outer periphery of the annular portion.

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

7. The shaft grounding member for rolling bearings according to claim 1, wherein, 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.

8. The shaft grounding member for rolling bearings according to claim 1, wherein, The elastic portion of the spring plate bends midway.

9. The shaft grounding member for rolling bearings according to claim 1, wherein, The elastic portion of the spring plate is formed flush with the annular portion.

10. 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, and... The rolling bearing unit is equipped with a rolling bearing shaft grounding member as described in any one of claims 1 to 9.

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