Sliding members and rolling bearings

Abstract

To improve the conductivity of the sliding member. [Solution] The sliding member is formed in an annular shape, forming a conductive path between a first member and a second member made of steel. The sliding member comprises a fixing portion formed on the first radial side and fixed to the first member, and a lip portion formed on the second radial side and sliding against the second member. The lip portion has a notch that opens at the edge of the second radial side, and a thick-walled portion located near the notch in the circumferential direction and having a greater axial thickness than the rest of the lip portion.

Description

Technical Field

[0001] The present disclosure relates to a sliding member and a rolling bearing.

Background Art

[0002] Patent Document 1 below discloses a conductive bearing having conductivity. This conductive bearing includes an outer ring, an inner ring, rolling elements, and a conductive ring. The conductive ring includes a fixing portion formed of a conductive resin and fixed to one of the outer ring and the inner ring, and a lip that contacts the other. This conductive bearing is used in an EV (Electric Vehicle) or HV (Hybrid Vehicle) including high-voltage components, and by flowing the current of the high-voltage components between the inner ring and the outer ring through the conductive ring, it prevents electrolytic corrosion generated on the rolling elements and the raceways of the inner and outer rings.

[0003] Also, the lip of the conductive ring in Patent Document 1 is formed in a discontinuous sawtooth shape in the circumferential direction, and by removing the oil film formed on the inner ring with the sawtooth-shaped lip, a decrease in conductivity is suppressed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Since the lip of the conductive ring in Patent Document 1 has a reduced rigidity due to being formed in a sawtooth shape, the contact state with the inner ring deteriorates, and there is a risk that the oil film cannot be sufficiently removed. If an oil film remains between the inner ring and the lip, the conductivity of the conductive ring decreases, making it difficult to prevent electrolytic corrosion of the inner and outer rings and the rolling elements.

[0006] Therefore, this disclosure aims to further improve the conductivity of sliding members. [Means for solving the problem]

[0007] (1) The present disclosure relates to an annular sliding member that forms a conductive path between a first member and a second member made of steel, A fixing portion formed on the first radial side and fixed to the first member, It comprises a lip portion formed on the second radial side and sliding in contact with the second member, The lip portion has a notch that opens at the second radial edge, and a thick-walled portion located near the notch in the circumferential direction, which has a greater axial thickness than the rest of the lip portion.

[0008] (2) The rolling bearing of the present disclosure comprises an inner ring having an inner ring raceway, An outer ring having an outer ring raceway arranged radially outside the inner ring raceway, A plurality of rolling elements are arranged to be rotatable between the inner ring raceway and the outer ring raceway, The sliding member described in (1) above is disposed radially between the axial end of the inner ring and the axial end of the outer ring, One of the inner ring and the outer ring is the first member, The other of the inner ring and the outer ring is the second member. [Effects of the Invention]

[0009] The sliding member of this disclosure can increase the rigidity of the lip portion near the notch by the thickened portion, remove the oil film present between the lip portion and the second member at the edge of the notch, and improve the conductivity of the sliding member. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a cross-sectional view showing a rolling bearing according to the first embodiment. [Figure 2] Figure 2 is an enlarged cross-sectional view of the sliding member. [Figure 3] Figure 3 is an enlarged cross-sectional view of the radially outer portion of the sliding member. [Figure 4] Figure 4 is an enlarged cross-sectional view of the radially inner portion of the sliding member. [Figure 5] Figure 5 is an overall side view of the sliding member as viewed from the direction of arrow A in Figure 2. [Figure 6] Figure 6 is a view showing an enlarged portion B in Figure 5. [Figure 7] Figure 7 is a view of the lip portion of the sliding member as viewed from the direction of arrow C in Figure 6. [Figure 8] Figure 8 is a cross-sectional view taken along the line D-D in Figure 6. [Figure 9] Figure 9 is a view corresponding to portion B in Figure 5 of the sliding member in the rolling bearing according to the second embodiment. [Figure 10] Figure 10 is a view of the lip portion of the sliding member as viewed from the direction of arrow E in Figure 9.

Embodiments for Carrying Out the Invention

[0011] > <Summary of Embodiments of the Invention of the Present Disclosure> Hereinafter, the summary of the embodiments of the invention of the present disclosure will be listed and described.

[0012] (1) The sliding member of the present disclosure is an annular sliding member that forms a conductive path between a first member and a second member made of steel material, a fixing portion formed on the first side in the radial direction and fixed to the first member, and a lip portion formed on the second side in the radial direction and in sliding contact with the second member, and the lip portion has a notch portion that opens at the edge on the second side in the radial direction, and a thick portion that is arranged in the circumferential direction near the notch and has a greater axial thickness than other portions of the lip portion.

[0013] According to this configuration, the rigidity of the lip portion in the vicinity of the notch portion can be increased by the thick portion of the lip portion, and the conductivity of the sliding member can be increased by removing the oil film existing between the lip portion and the second member at the edge of the notch portion. Further, by forming the notch portion, the contact area of the lip portion with respect to the second member can be reduced, and the sliding load torque can be reduced.

[0014] (2) In the sliding member according to (1) above, the thick portion is located at the circumferential edge of the notch portion. According to this configuration, the rigidity of the lip portion at the edge of the notch portion can be increased by the thick portion, and the effect of removing the oil film existing between the lip portion and the second member can be further enhanced.

[0015] (3) In the sliding member according to (1) or (2) above, the lip portion has the thick portions on both circumferential sides of the notch portion. According to this configuration, the rigidity of the lip portion on both circumferential sides of the notch portion can be increased by the thick portions, and the oil film can be appropriately removed regardless of whether the lip portion slides on the second member in the circumferential direction on either side.

[0016] (4) In the sliding member according to any one of (1) to (3) above, the thick portion has a constant axial thickness in the circumferential direction. According to this configuration, the rigidity of the lip portion in the portion where the thick portion is formed can be further increased.

[0017] (5) In the sliding member according to any one of (1) to (3) above, the thick portion is formed thinner in the axial direction as it moves away from the notch portion in the circumferential direction. According to this configuration, by further increasing the rigidity of the lip portion in the vicinity of the notch portion, the effect of removing the oil film can be enhanced, and at a position away from the notch portion in the circumferential direction, by forming the thick portion thinner, the difference in thickness (cross-sectional change) between the thick portion of the lip portion and the portion other than the thick portion can be reduced, and breakage from the boundary between the thick portion and the portion other than the thick portion can be suppressed.

[0018] (6) The sliding member described in any one of (1) to (5) above is a sheet which is a nonwoven or woven fabric made of conductive fibers, The sheet comprises a rubber bonded to the sheet, The aforementioned sheet is It is continuous in the radial direction across the fixed portion and the lip portion. According to this configuration, a sheet made of nonwoven or woven fabric formed of conductive fibers can have higher conductivity than one made of conductive resin, such as the conductive ring described in Patent Document 1. Therefore, the sliding member can form a conductive path between the first member and the second member by the sheet, and current can flow from one of the first member and the second member to the other through this sheet.

[0019] (7) The rolling bearing of the present disclosure comprises an inner ring having an inner ring raceway, An outer ring having an outer ring raceway arranged radially outside the inner ring raceway, A plurality of rolling elements are arranged to be rotatable between the inner ring raceway and the outer ring raceway, The sliding member described in any one of (1) to (6) above is positioned radially between the axial end of the inner ring and the axial end of the outer ring, The inner ring and the outer ring are the first member, The other of the inner ring and the outer ring is the second member.

[0020] With this configuration, a conductive path can be formed between the outer ring and inner ring of the rolling bearing by the sliding member, and current can be passed from one of the outer ring and inner ring to the other through this sliding member, thereby suppressing electrolytic corrosion of the outer ring raceway, inner ring raceway, and balls.

[0021] <Details of Embodiments of the Invention in This Disclosure> Embodiments of the invention described herein will be explained below. [First Embodiment] Figure 1 is a cross-sectional view showing a rolling bearing according to the first embodiment. The rolling bearing 10 shown in Figure 1 supports the rotating shaft S of a motor mounted in, for example, an electric vehicle or a hybrid vehicle. In Figure 1, the rotating shaft S is indicated by a dashed line (two-dot dashed line).

[0022] The rolling bearing 10 comprises an outer ring 11, an inner ring 12, a plurality of rolling elements 13, a cage 14, and a sliding member 15. In this embodiment, the rolling elements 13 are balls. The rolling bearing 10 is a deep groove ball bearing. The outer ring 11 is mounted on the housing H of the motor. The inner ring 12 is fitted and fixed to the outer circumferential surface of the rotating shaft S. In Figure 1, the housing H and the rotating shaft S are shown by dashed lines (two-dot dashed lines). In this embodiment, the outer ring 11 is a stationary ring, and the inner ring 12 is a rotating ring. The outer ring 11 and the inner ring 12 are formed from a steel material such as bearing steel. High-carbon chromium bearing steel (for example, SUJ2 or SUJ3 as defined in JIS standards) can be used as the bearing steel. However, the outer ring 11 and the inner ring 12 may be made of other steel materials such as carburized bearing steel, carbon steel, chromium steel, or stainless steel.

[0023] The outer ring 11 and the inner ring 12 are arranged concentrically. In this embodiment, the central axes of the outer ring 11 and the inner ring 12 coincide with the central axis C of the rolling bearing 10. Furthermore, in this embodiment, the direction along the central axis C and the direction parallel to the central axis C are defined as the "axial direction". Similarly, the direction perpendicular to the central axis C is defined as the "radial direction". Similarly, the direction along the circle centered on the central axis C is defined as the "circumferential direction". Also, in this embodiment, the left side of Figure 1 is the first axial side, the right side of Figure 1 is the second axial side, the upper side of Figure 1 is the first radial side, and the lower side of Figure 1 is the second radial side. Also, in this embodiment, the first radial side is the radially outer side, and the second radial side is the radially inner side. Therefore, in the following description, the first radial side may be referred to as the radially inner side, and the second radial side may be referred to as the radially outer side.

[0024] The outer ring 11 comprises an outer ring raceway 21, two shoulders 22, and two annular grooves 23. The outer ring raceway 21 is provided on the inner circumferential surface of the outer ring 11. The ball 13 rolls along this outer ring raceway 21. The two shoulders 22 are provided on both axial sides of the outer ring raceway 21. The two annular grooves 23 are provided between the shoulders 22 and the axial sides of the outer ring 11. The annular grooves 23 have an annular groove shape that is continuous in the circumferential direction. The sliding member 15 is attached to the annular grooves 23 located on both axial sides of the outer ring 11. However, the sliding member 15 may be attached only to the annular grooves 23 located on either the first or second axial side of the outer ring 11. In this case, the annular grooves 23 to which the sliding member 15 is not attached may be omitted.

[0025] The inner ring 12 comprises an inner ring raceway 31, two shoulders 32, and two sliding member contact surfaces 33. The inner ring raceway 31 is provided on the outer circumferential surface of the inner ring 12. The ball 13 rolls along this inner ring raceway 31. The two shoulders 32 are provided on both axial sides of the inner ring raceway 31. The two sliding member contact surfaces 33 are provided between the shoulders 32 and the sides of the inner ring 12. The sliding member contact surfaces 33 are provided in an annular shape around the entire circumference of the inner ring 12. The sliding member contact surfaces 33 have a groove shape in a cross-section including the central axis C of the inner ring 12. The radial inner end of the sliding member 15 is in contact with the sliding member contact surface 33.

[0026] The ball 13 is positioned between the outer ring 11 and the inner ring 12. The ball 13 rolls and makes contact with the outer ring raceway 21 and the inner ring raceway 31. Multiple balls 13 are held circumferentially at intervals by an annular retainer 14.

[0027] The retainer 14 has an annular body 16 and a plurality of horns (columns) 17. The annular body 16 is located on the second axial side of the ball 13. The plurality of horns (columns) 17 extend from the annular body 16 on the first axial side. The pocket 18 is the space between two circumferentially adjacent horns 17 on the first axial side of the annular body 16. The pocket 18 accommodates the ball 13. The pocket 18 is open on the first axial side.

[0028] The sliding member 15 is formed in an annular shape. The sliding member 15 is fixed to the outer ring (first member) 11 and slides against the inner ring (second member) 12. Specifically, the sliding member 15 is fixed to the outer ring 11 by fitting its radially outer end (the end on the first radial side) into the annular groove 23 of the outer ring 11. The radially inner end (the end on the second radial side) of the sliding member 15 is in contact with the sliding member contact surface 33 of the inner ring 12. The sliding member 15 is provided on both axial sides of the rolling bearing 10. Therefore, the annular space between the outer ring 11 and the inner ring 12, the bearing internal space K1 in which the ball 13 exists, is closed off by the sliding member 15 on both axial sides. The sliding member 15 separates the bearing internal space K1 in which the ball 13 exists from the bearing external space K2, which is the space on the first and second axial sides of the rolling bearing 10.

[0029] The sliding member 15 includes a conductive sheet 43 positioned between its radially outer end and radially inner end. At the radially outer end of the sliding member 15, the sheet 43 is exposed on the surface and in contact with the annular groove 23 of the outer ring 11. At the radially inner end of the sliding member 15, the sheet 43 is exposed on the surface and in contact with the sliding member contact surface 33 of the inner ring 12. Therefore, the sliding member 15 forms an energizing path to suppress the flow of current generated by a motor or the like between the outer ring 11 and the inner ring 12 via the rolling elements 13.

[0030] An oil film of lubricating oil or grease is formed between the ball 13 and the inner ring raceway 31, and between the ball 13 and the outer ring raceway 21. The oil film has insulating properties. Due to the insulating properties of the oil film, the ball 13 is insulated from the inner ring raceway 31 and from the outer ring raceway 21. When an oil film is formed between the ball 13 and the inner ring raceway 31, and a potential difference of less than a predetermined value occurs between the ball 13 and the inner ring raceway 31, no current flows between the inner ring raceway 31 and the ball 13. When an oil film is formed between the ball 13 and the outer ring raceway 21, and a potential difference of less than a predetermined value occurs between the ball 13 and the outer ring raceway 21, no current flows between the ball 13 and the outer ring raceway 21. However, when the oil film between the ball 13 and the inner ring raceway 31 is partially destroyed, or when a potential difference exceeding a predetermined value occurs between the ball 13 and the inner ring raceway 31, current flows between the ball 13 and the inner ring raceway 31, and this current may cause electrolytic corrosion on the ball 13 and / or the inner ring raceway 31. When the oil film between the ball 13 and the outer ring raceway 21 is partially destroyed, or when a potential difference exceeding a predetermined value occurs between the ball 13 and the outer ring raceway 21, current flows between the ball 13 and the outer ring raceway 21, and this current may cause electrolytic corrosion on the ball 13 and / or the outer ring raceway 21.

[0031] In this embodiment, the rolling bearing 10 is provided with a sliding member 15 that forms an electrical path. Therefore, before the potential difference between the ball 13 and the inner ring raceway 31, and the potential difference between the ball 13 and the outer ring raceway 21 become large, the potential difference between the outer ring 11 and the inner ring 12 is reduced by passing current between the outer ring 11 and the inner ring 12 via the sliding member 15. By reducing the potential difference between the outer ring 11 and the inner ring 12, the occurrence of electrolytic corrosion of the ball 13, the inner ring raceway 31, and the outer ring raceway 21 is suppressed.

[0032] [Specific structure of the sliding member 15] Figure 2 is an enlarged cross-sectional view of the sliding member. Figure 3 is an enlarged cross-sectional view of the radially outer portion of the sliding member. Figure 4 is an enlarged cross-sectional view of the radially inner portion of the sliding member. In the following description, the specific structure of the sliding member 15 located on the first axial side (left side in Figure 1) of the rolling bearing 10 will be explained. Therefore, in this description of the sliding member 15, the first axial side can be rephrased as the bearing external space K2 side, and the second axial side can be rephrased as the bearing internal space K1 side. The sliding member 15 located on the second axial side (right side in Figure 1) of the rolling bearing 10 is the same part as the sliding member 15 located on the first side, but it is located inverted in the axial direction.

[0033] As shown in Figures 2 to 4, the sliding member 15 has a metal ring 41, a rubber 42, and a sheet 43. The metal ring 41, the rubber 42, and the sheet 43 are all annular. The metal ring 41 and the rubber 42, and the rubber 42 and the sheet 43 are bonded to each other, and they form a single integrated unit.

[0034] The metal ring 41 is formed from a metal such as galvanized steel sheet or stainless steel. The metal ring 41 is formed by processing a sheet material. The metal ring 41 includes an annular portion 41a and a cylindrical portion 41b. The annular portion 41a is positioned perpendicular to the axial direction. The cylindrical portion 41b is positioned parallel to the axial direction. The cylindrical portion 41b is positioned at the radially outer end of the annular portion 41a. The cylindrical portion 41b extends from the radially outer end of the annular portion 41a to the second axial side (bearing internal space K1 side). The annular portion 41a and the cylindrical portion 41b of the metal ring 41 are formed by plastically deforming a sheet material into a substantially L-shaped cross-section.

[0035] The rubber 42 is electrically conductive. Specifically, the rubber 42 is manufactured, for example, by compounding a conductive material with synthetic rubber. The conductive material may be carbon black, metal powder, etc. The specific structure of this rubber 42 will be described later, along with the structure of the sheet 43.

[0036] The sheet 43 is made of a nonwoven or woven fabric made of conductive fibers. In this embodiment, carbon fibers are used as the conductive fibers in the sheet 43. However, the conductive fibers may be made of other materials, such as conductive metals like copper or nickel. The electrical resistance of the sheet 43 is lower than that of the rubber 42. Therefore, the sheet 43 has higher conductivity than the rubber 42.

[0037] In this embodiment, the sheet 43 further contains a synthetic resin as a binder. The binder is fixed to the surface of some of the conductive fibers contained in the sheet 43. The sheet 43 in this embodiment is a nonwoven or woven fabric made of conductive fibers with the binder fixed to it.

[0038] The sheet 43 integrally comprises an intermediate portion 44, a fixed portion 45, and a sliding portion 46. The fixed portion 45 is the part located radially outward (radially first side) of the metal ring 41. The sliding portion 46 is the part located radially inward (radially second side) of the metal ring 41. The intermediate portion 44 is the part located radially between the fixed portion 45 and the sliding portion 46.

[0039] The intermediate portion 44 of the sheet 43 has a first portion 44a, a second portion 44b, and a third portion 44c. The first portion 44a extends radially. As shown in Figures 3 and 4, the first portion 44a is positioned on the second axial side (bearing internal space K1 side) of the annular portion 41a of the metal ring 41 with a gap t1 between them.

[0040] The second portion 44b bends from the radially outer end of the first portion 44a to the second axial side and extends axially. Therefore, the second portion 44b is formed in a cylindrical shape. As shown in Figure 3, the second portion 44b is positioned radially inward of the cylindrical portion 41b of the metal ring 41 with a gap t2 between them.

[0041] The third portion 44c bends radially outward from the second axial end of the second portion 44b and extends radially. As shown in Figure 3, the third portion 44c is positioned at a gap t3 on the second axial side of the cylindrical portion 41b of the metal ring 41. Therefore, the intermediate portion 44 of the sheet 43 and the metal ring 41 are positioned at gaps t1, t2, and t3 throughout the radial direction.

[0042] The fixing portion 45 of the sheet 43 is formed in a continuous manner with the third portion 44c of the intermediate portion 44. As shown in Figure 3, the fixing portion 45 has a fourth portion 45a and a fifth portion 45b. The fourth portion 45a extends radially in a continuous manner from the radially outer end of the third portion 44c of the intermediate portion 44. The fifth portion 45b extends from the radially outer end of the fourth portion 45a, inclined toward the axial first side and radially outward. The tip of the fifth portion 45b constitutes the radially outer end of the sheet 43. The tip of the fifth portion 45b is in direct contact with the annular groove 23 of the outer ring 11. In this embodiment, the fourth portion 45a of the fixing portion 45 is also in direct contact with the annular groove 23. A part of the third portion 44c of the intermediate portion 44 is also in direct contact with the annular groove 23.

[0043] As shown in Figures 2 and 4, the sliding portion 46 of the sheet 43 is formed continuously with the first portion 44a, which is the intermediate portion 44. In this embodiment, the portion of the sheet 43 that is located radially inward from the radially inward end of the metal ring 41 is defined as the sliding portion 46. The sliding portion 46 extends linearly radially inward from the first portion 44a of the intermediate portion 44. Therefore, the first portion 44a of the intermediate portion 44 and the sliding portion 46 are formed as a whole in an annular shape perpendicular to the axial direction. The radially inward end 46a of the sliding portion 46 is in direct contact with the sliding member contact surface 33 of the inner ring 12. The radially inward end 46a of the sliding portion 46 is bent toward the first axial direction by contacting the sliding member contact surface 33.

[0044] As shown in Figure 2, the rubber 42 is bonded to the sheet 43 and the metal ring 41. The rubber 42 is provided over the entire axial first side (bearing external space K2 side) of the sheet 43. The rubber 42 has a first portion 42c, a second portion 42a, a third portion 42b, and a fourth portion 42d.

[0045] The second portion 42a of the rubber 42 is positioned at the intervals t1, t2, and t3 formed between the metal ring 41 and the sheet 43. The second portion 42a of the rubber 42 maintains the intervals t1, t2, and t3 between the metal ring 41 and the sheet 43 so that the metal ring 41 and the sheet 43 are not directly bonded together.

[0046] The third portion 42b of the rubber 42 is formed continuously on the radially outer side of the second portion 42a. The third portion 42b is located in the region surrounded by the fixing portion 45 of the sheet 43 and the cylindrical portion 41b of the metal ring 41. The third portion 42b of the rubber 42 elastically supports the fifth portion 45b of the sheet 43 from the radially inner side. The cylindrical portion 41b of the metal ring 41 supports the third portion 42b of the rubber 42 from the radially inner side. Therefore, the fixing portion (radially outer end) 45 of the sheet 43 is pressed against the annular groove 23 of the outer ring 11 by the elasticity of the third portion 42b of the rubber 42, which is supported by the cylindrical portion 41b of the metal ring 41, and is reliably brought into contact with the annular groove 23. In this specification, the fixing portion 47 of the sliding member 15 fixed to the outer ring 11 is formed by both the fixing portion 45 of the sheet 43 and the third portion 42b of the rubber 42.

[0047] As shown in Figure 4, the first portion 42c of the rubber 42 extends radially inward from the radially inward end of the second portion 42a of the rubber 42. The first portion 42c extends radially inward with a substantially constant thickness along the axially first side surface of the sliding portion 46 of the sheet 43. The first portion 42c is formed in an annular shape perpendicular to the axial direction. As the radially inward end 46a of the sliding portion 46 of the sheet 43 contacts the sliding member contact surface 33 and bends, the first portion 42c of the rubber 42 elastically deforms and bends together with the sliding portion 46 on the axially first side. In Figure 4, the sliding portion 46 and the first portion 42c in the unloaded state before elastic deformation are shown by dashed lines, and the sliding portion 46 and the first portion 42c after elastic deformation are shown by solid lines. In this embodiment, the portion of the sheet 43 that includes the sliding portion 46 and the first portion 42c of the rubber 42 that is adhered to the sliding portion 46 is also referred to as the "lip portion 48" of the sliding member 15.

[0048] The fourth portion 42d of the rubber 42 extends from the radially outer end of the first portion 42c, beyond the radially inner end of the metal ring 41, and is positioned on the axially first side surface of the metal ring 41. Thus, the fourth portion 42d has a substantially L-shaped cross-section and covers and adheres to the radially inner end surface and the axially second side surface of the annular portion 41a. The fourth portion 42d of the rubber 42 helps to firmly bond the rubber 42 to the metal ring 41 and prevents the rubber 42 from peeling off the metal ring 41.

[0049] Since the rubber 42 has higher rigidity than the sheet 43, the sheet 43 maintains its shape by the rubber 42. In addition, the middle portion 44 of the sheet 43 also maintains its shape by the metal ring 41.

[0050] The sheet 43 is made of a nonwoven or woven fabric formed of conductive fibers. In its material state before the manufacture of the sliding member 15, the sheet 43 contains voids inside. After the manufacture of the sliding member 15, the rubber 42 is also present in the voids of the sheet 43. As will be described later, the sliding member 15 is manufactured by inserting the metal ring 41 and the sheet 43 into a mold, vulcanizing the rubber material constituting the rubber 42, molding it into a predetermined shape, and bonding the rubber material to the metal ring 41 and the sheet 43. Hereinafter, this manufacturing process will also be referred to as "vulcanization bonding". During this vulcanization bonding, the rubber 42 enters the voids of the sheet 43. During vulcanization bonding, the rubber 42 is easily bonded to the binder.

[0051] The fixed portion 45 of the sheet 43 is exposed on the surface of the sliding member 15 and contacts the annular groove 23 of the outer ring 11. The sliding portion 46 of the sheet 43 is also exposed on the surface of the sliding member 15 and contacts the sliding member contact surface 33 of the inner ring 12. Since the multiple conductive fibers constituting the sheet 43 are in contact with each other, the sheet 43 is conductive from the fixed portion 45 to the sliding portion 46 due to the contact between the conductive fibers. Since the sheet 43 is in contact with the outer ring 11 and the inner ring 12, the outer ring 11 and the inner ring 12 are electrically connected via the sheet 43. In addition, the conductive metal ring 41 and rubber 42 are in contact with the sheet 43. The outer ring 11 and the inner ring 12 are electrically connected not only via the sheet 43 but also via the conductive metal ring 41 and rubber 42.

[0052] Therefore, the sliding member 15 of this embodiment can dissipate electric charge from one of the fixed portion 45 and the sliding portion 46 to the other. Furthermore, the sliding member 15 of this embodiment can dissipate electric charge from one of the member fixing the fixed portion 45 and the member on which the sliding portion 46 slides to the other. The rolling bearing 10 of this embodiment can dissipate electric charge from one of the outer ring 11 and the inner ring 12 to the other via the sliding member 15, thereby suppressing electrolytic corrosion of the balls 13 and the raceways 21 of the outer ring and 31 of the inner ring on which the balls 13 roll.

[0053] As shown in Figure 2, the seat 43 is positioned on the second axial side (bearing internal space K1 side) of the sliding member 15. On the other hand, the sliding member contact surface 33 formed on the inner ring 12 is a surface facing the first axial side (bearing external space K2 side). Therefore, the sliding portion 46 of the seat 43 is easily brought into contact with the sliding member contact surface 33. However, if the sliding member contact surface 33 is a surface facing the second axial side, the sliding member 15 may be formed such that the seat 43 is positioned on the first axial side of the sliding member 15.

[0054] (German construction of the lip section) Figure 5 is an overall side view of the sliding member as seen from direction A, as indicated by arrow A in Figure 2. Figure 6 is an enlarged view of section B in Figure 5. Figure 7 is a view of the lip portion of the sliding member as seen from direction C, as indicated by arrow C in Figure 6. Figure 8 is a cross-sectional view as indicated by arrow DD in Figure 6. As shown in Figure 5, the sliding member 15 is formed in an annular shape, with a fixing portion 47 provided on its radially outer side and a lip portion 48 provided on its radially inner side. Multiple notches 48a are formed at the radially inner end of the lip portion 48. In this embodiment, four notches 48a are formed at equal intervals (90° intervals) in the circumferential direction.

[0055] As shown in Figure 6, the notch 48a opens radially inward. In this embodiment, the notch 48a is formed in a substantially rectangular shape. Specifically, the notch 48a is formed in a substantially rectangular shape in which the circumferential length is greater than the radial length (depth). However, the notch 48a is not limited to a rectangular shape and may be formed in shapes such as a semicircle, semiellipse, or triangular shape. Also, the number of notches 48a may be one or more than four.

[0056] As shown in FIGS. 6 to 8, the lip portion 48 has a thick portion 48b. The thick portion 48b is a portion where the axial thickness is larger than other portions of the lip portion 48. Hereinafter, the portion of the lip portion 48 other than the thick portion 48b is also referred to as a thin portion 48c. The thick portion 48b is arranged in the vicinity of the notch portion 48a in the circumferential direction. More specifically, the thick portion 48b is arranged adjacent to the notch portion 48a in the circumferential direction. Therefore, the thick portion 48b constitutes the circumferential edge of the notch portion 48a. The thick portion 48b is provided on both sides in the circumferential direction of the notch portion 48a.

[0057] As shown in FIG. 7, the thick portion 48b has a constant axial thickness in the circumferential direction. As shown in FIG. 8, the thickness t4 of the thick portion 48b is smaller than twice the thickness t5 of the thin portion 48c. Therefore, the thickness t4 of the thick portion 48b and the thickness t5 of the thin portion 48c are in the relationship of t5 < t4 ≦ 2.0t5. However, it is not limited to such a relationship, and the relationship between the thickness t4 of the thick portion 48b and the thickness t5 of the thin portion 48c can be changed as appropriate. For example, the thickness t4 of the thick portion 48b and the thickness t5 of the thin portion 48c may be in the relationship of 2.0t5 < t4.

[0058] As shown in FIG. 8, the end portion on the second side in the axial direction of the thick portion 48b is constituted by the sliding portion 46 of the sheet 43, similar to the thin portion 48c. The sheet 43 has a constant thickness as a whole. Therefore, the thickness of the rubber 42 in the thick portion 48b is larger than the thickness of the rubber in the thin portion 48c, and the difference in thickness between the thick portion 48b and the thin portion 48c is caused by the difference in the thickness of the rubber 42. The thick portion 48b protrudes toward the first side in the axial direction more than the thin portion 48c.

[0059] As shown in FIGS. 6 and 8, the thick portion 48b extends further radially outward from the radially inner end of the lip portion 48 beyond the notch portion 48a. The radially outer end of the thick portion 48b reaches the fourth portion 42d of the rubber 42. The portion located between the two thick portions 48b radially outside the notch portion 48a is regarded as the thin portion 48c.

[0060] In this embodiment, the sliding member 15 has a notch 48a formed in the lip portion 48, which reduces the contact area with the inner ring 12 and reduces the rotational torque (load torque due to sliding) of the inner ring 12 and the rotating shaft S. Furthermore, if an oil film, which acts as an insulator, is present between the lip portion 48 and the inner ring 12, the conductive path between the outer ring 11 and the inner ring 12 formed by the sliding member 15 is blocked, increasing the likelihood that current will flow through the outer ring raceway 21, the ball 13, and the inner ring raceway 31 as conductive paths. In this embodiment, the circumferential edge of the notch 48a acts to scrape or push away the oil film, removing the oil film between the inner ring 12 and the lip portion 48. Therefore, a conductive path between the outer ring 11 and the inner ring 12 via the sliding member 15 can be suitably secured.

[0061] Furthermore, if a notch 48a is formed in the lip portion 48, the rigidity of the lip portion 48 in its vicinity decreases, potentially worsening the contact between the lip portion 48 and the inner ring 12 and reducing the oil film removal effect. In this embodiment, however, the rigidity of the lip portion 48 is increased by forming a thickened portion 48b near the notch 48a, thus suppressing a decrease in the oil film removal effect. In particular, since the thickened portion 48b constitutes the circumferential edge of the notch portion 48a, the rigidity at this edge is increased, thereby enhancing the oil film removal effect.

[0062] The thickened portion 48b may be formed only on one side of the notch 48a in the circumferential direction. In this case, it is preferable that the thickened portion 48b is formed on one side of the notch 48a in the circumferential direction, which is downstream in the rotational direction of the inner ring 12. This allows for a favorable increase in the rigidity of the edge of the notch 48a, which has the effect of removing the oil film.

[0063] [Second Embodiment] Figure 9 is a diagram of the sliding member in the rolling bearing according to the second embodiment, corresponding to part B in Figure 5. Figure 10 is a view of the lip portion of the sliding member as seen from the direction of arrow E in Figure 9. As shown in Figures 9 and 10, the sliding member 15 of this embodiment differs from the first embodiment in the shape of the thickened portion 48b. Specifically, the thickness of the thickened portion 48b in this embodiment varies in the circumferential direction. Specifically, the thickened portion 48b is formed to gradually become thinner as it moves away from the notch portion 48a in the circumferential direction. Therefore, the surface of the thickened portion 48b on the first axial side is formed in an inclined shape. The thickness of the end of the thickened portion 48b furthest from the notch portion 48a is the same as the thickness of the thinned portion 48c.

[0064] In this embodiment as well, the thickened portion 48b increases the rigidity of the lip portion 48 near the notch portion 48a, thereby suppressing a decrease in the oil film removal effect. Furthermore, in this embodiment, the thickness of the thickened portion 48b gradually decreases as it moves away from the notch portion 48a, approaching the thickness of the thinned portion 48c, so the change in shape at the boundary with the thinned portion 48c becomes gradual. Therefore, stress concentration at this boundary can be suppressed.

[0065] [Other embodiments] In the sliding member 15 of the above embodiment, the thickened portion 48b was formed adjacent to the notch portion 48a and constituted the edge of the notch portion 48a. However, it may be formed at a position circumferentially away from the notch portion 48a, as long as it can increase the rigidity of the lip portion 48 in the vicinity of the notch portion 48a.

[0066] In the sliding member 15 of the above embodiment, the thick portion 48b protruded only on the first axial side of the lip portion 48 relative to the thin portion 48c, but it may also protrude only on the second side, or on both the first and second sides. However, by having the thick portion 48b protrude only on the first axial side of the lip portion 48 relative to the thin portion 48c, the surface of the second side of the lip portion 48 that contacts the inner ring 12 can be made smoother, and a sufficient contact area between the two that form the conductive path can be secured.

[0067] In the sliding member 15 of the above embodiment, the sliding portion 46 of the sheet 43 was positioned on the second axial side of the lip portion 48, and the first portion 42c of the rubber 42 was positioned on the first axial side of the sliding portion 46. However, the sliding portion 46 of the sheet 43 may be positioned on the first axial side of the lip portion 48, and the first portion 42c of the rubber 42 may be positioned on the second axial side of the sliding portion 46.

[0068] In the sliding member 15 of the above embodiment, the metal ring 41 is positioned on the first axial side of the rubber 42, but it may also be positioned on the second axial side of the sheet 43.

[0069] In the sliding member 15 of the above embodiment, the sheet 43 may be omitted. That is, the sliding member 15 may be composed of conductive rubber 42 and a metal ring 41.

[0070] In the rolling bearing 10 of the above embodiment, the outer ring 11 is a fixed ring and the inner ring 12 is a rotating ring. However, in the rolling bearing 10 of the present invention, the outer ring 11 may be a rotating ring and the inner ring 12 may be a fixed ring.

[0071] In the above embodiment, the sliding member 15 is fixed to the outer ring 11, which is the first member, and is in slidable contact with the inner ring 12, which is the second member. On the other hand, in the present invention, the sliding member may be fixed to the inner ring 12, which is the first member, and be in slidable contact with the outer ring 11, which is the second member.

[0072] In the above embodiment, the sliding member 15 had a synthetic resin as a binder fixed to the conductive fibers constituting the sheet 43. On the other hand, in the sheet of the present invention, the conductive fibers constituting the sheet do not need to have a synthetic resin as a binder.

[0073] In the above embodiment, the case in which the rolling bearing 10 is a deep groove ball bearing was described. However, in the present invention, the rolling bearing 10 may be an angular contact ball bearing, or a roller bearing in which the rolling elements are rollers, etc.

[0074] In the above embodiment, the sliding member 15 was used in a rolling bearing 10. However, the sliding member 15 of the present invention may be used in a device in which it is fixed to one of two relatively moving members and slidably contacts the other member. For example, in a device having a housing and a rotating shaft that rotates within the housing, the sliding member 15 can be used to form a conductive path between the housing and the rotating shaft.

[0075] The embodiments described above are illustrative and not restrictive in all respects. The scope of the present invention is indicated by the claims rather than by the embodiments, and includes all modifications within the scope of equivalence to the configurations described in the claims. [Explanation of symbols]

[0076] 10: Rolling bearings 11: Outer ring 12: Inside 13: Rolling element 15: Sliding member 21: Outer ring track 31: Inner track 42: Rubber 43: Sheet 46: Sliding part 47:Fixed part 48: Lip part 48a: Notch 48b: Thick wall part 48c: Thin wall part

Claims

1. An annular sliding member that forms a conductive path between a first member and a second member made of steel, A fixing portion formed on the first radial side and fixed to the first member, It comprises a lip portion formed on the second radial side and sliding in contact with the second member, The sliding member has a lip portion having a notch that opens at the second radial edge and a thick-walled portion located near the notch in the circumferential direction and having a greater axial thickness than the rest of the lip portion.

2. The sliding member according to claim 1, wherein the thickened portion is located at the circumferential edge of the notched portion.

3. The sliding member according to claim 1 or 2, wherein the lip portion has the thickened portion on both sides in the circumferential direction of the notch portion.

4. The sliding member according to claim 1 or 2, wherein the thickened portion has a constant axial thickness in the circumferential direction.

5. The sliding member according to claim 1 or 2, wherein the thickened portion is formed to become thinner in the axial direction as it moves away from the notched portion in the circumferential direction.

6. A sheet which is a nonwoven or woven fabric formed of conductive fibers, The sheet comprises a rubber bonded to the sheet, The aforementioned sheet is The sliding member according to claim 1 or 2, which is radially continuous across the fixed portion and the lip portion.

7. An inner ring having an inner track, An outer ring having an outer ring raceway arranged radially outside the inner ring raceway, A plurality of rolling elements are arranged to be rotatable between the inner ring raceway and the outer ring raceway, The sliding member is disposed in the radial direction between the axial end of the inner ring and the axial end of the outer ring, as described in claim 1 or 2. One of the inner ring and the outer ring is the first member, A rolling bearing in which the other of the inner ring and the outer ring is the second member.

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