Rolling bearing

Abstract

The purpose of the present invention is to improve workability of arranging a spring member made of an electroconductive wire between a groove part of an inner circumference of an outer ring and an outer circumference of an inner ring. A spring member (50) includes: an outer diameter wire part (51) fitted into a groove part (24) in the inner circumference of an outer ring (20); and a contact wire part (52) pressed against the outer circumference of an inner ring (10) by the spring force of the spring member (50). The outer circumference of the inner ring (10) includes: an end part (14) having no radial interference with respect to the spring member (50); and a step part (15) protruding radially outward from the end part (14). The end part (14) extends continuously between the step part (15) and a width surface part (12) positioned at one end of the entire width of the inner ring (10). The contact wire part (52) is pressed against the step part (15) in the axial direction by an axial spring force.

Description

Rolling bearing

[0001] This invention relates to a rolling bearing provided with a conductive path that does not pass through rolling elements between the outer circumference of the inner ring and the inner circumference of the outer ring.

[0002] When a rotating part is supported by a rolling bearing in a device that uses electricity, such as an electric motor or an e-Axle that integrates an electric motor and a speed reducer, a voltage may be applied to the rolling bearing. When electricity flows from the outer ring of the rolling bearing to the inner ring side via the rolling elements or from the inner ring to the outer ring side via the rolling elements due to this voltage, electric erosion occurs at the rolling contact portions between the rolling elements and the outer ring and the inner ring.

[0003] Conventionally, in order to prevent such electric erosion, a groove portion is formed on one end side of the inner circumference of the outer ring, a cylindrical surface portion is formed on one end side of the outer circumference of the inner ring, and the outer diameter side of a spring member made of a single conductive wire rod of a substantially C shape or a substantially spiral shape is fitted into the groove portion of the outer ring, and the inner diameter side of the spring member overlaps with the cylindrical surface portion of the inner ring in the radial direction, and due to the elastic repulsion in the radial direction of the spring member, the spring member, the groove portion of the outer ring, and the cylindrical surface portion of the inner ring are configured to be kept in contact (Patent Documents 1 and 2). This type of rolling bearing has a simple structure in which the spring member is held in the groove portion of the inner circumference of the outer ring and brought into contact with the outer circumference of the inner ring, so there is no problem in use under oil lubrication, and it is also possible to suppress an increase in bearing width and cost.

[0004] Japanese Patent Application Laid-Open No. 11-218143, Utility Model Laid-Open No. 2-110717

[0005] However, the substantially C-shaped or substantially spiral spring member disclosed in Patent Documents 1 and 2 has a problem in workability when arranging the spring member between the groove portion of the outer ring and the cylindrical surface portion of the inner ring in a state where the spring member is preloaded in order to ensure radial contact between the inner diameter side of the spring member and the cylindrical surface portion of the inner ring. That is, in the arrangement process, it is necessary to radially deform both the outer diameter side and the inner diameter side of the spring member, and at the same time, while inserting the outer diameter side into the groove portion of the outer ring, overlap the inner diameter side with the cylindrical surface portion of the inner ring, and it is difficult to maintain the deformation and posture of the spring member during this operation.

[0006] In light of the above-mentioned background, the problem that this invention aims to solve is to improve the workability of arranging a spring member made of conductive wire, which electrically connects the outer circumference of the inner ring and the inner circumference of the outer ring, between the groove on the inner circumference of the outer ring and the outer circumference of the inner ring.

[0007] To solve the above problems, this invention adopts a rolling bearing configuration 1 comprising an inner ring, an outer ring, a plurality of rolling elements disposed between the inner ring and the outer ring, and a spring member electrically connecting the outer circumference of the inner ring and the inner circumference of the outer ring, wherein the spring member is formed of a conductive wire, the inner circumference of the outer ring includes a groove extending in the circumferential direction, and the spring member includes an outer diameter wire portion fitted into the groove and a contact wire portion pressed against the outer circumference of the inner ring by the spring force of the spring member, wherein the outer circumference of the inner ring includes an end portion that does not have radial interference with respect to the spring member and a stepped portion protruding radially outward from the end portion, the end portion is continuous between a width surface portion located at one end of the total width of the inner ring and the stepped portion, and the contact wire portion is pressed axially against the stepped portion by the spring force.

[0008] According to the above configuration 1, when the outer diameter portion of the spring member is elastically deformed radially inward to fit into the groove portion of the outer ring, it is not necessary to elastically deform the contact portion of the spring member radially outward. Instead, it is sufficient to simply pass it over the end of the inner ring and press it axially against the stepped portion. This makes it easier to position the spring member between the inner circumference of the outer ring and the outer circumference of the inner ring.

[0009] In the above configuration 1, configuration 2 can be adopted in which the contact line portion of the spring member is formed at a position axially inward relative to the outer diameter line portion so that the contact line portion and the stepped portion of the inner ring are always maintained in contact by the axial spring force.

[0010] According to the above configuration 2, the spring member is compressed axially by the groove portion of the outer ring and the stepped portion of the inner ring, generating a spring force that presses the contact line portion against the stepped portion. At the same time, the pressure of the contact line portion against the stepped portion can be maintained by following the relative displacement between the inner ring and the outer ring due to the axial clearance of the rolling bearing.

[0011] In the above configuration 2, a configuration 3 can be adopted in which the outer diameter line portion of the spring member is formed in an arc shape extending circumferentially along the groove portion of the outer ring, and the contact line portion is formed in an arc shape extending circumferentially along the stepped portion of the inner ring.

[0012] According to the above configuration 3, the contact length between the groove portion of the outer ring and the outer diameter line portion of the spring member is large in the circumferential direction, and the contact length between the stepped portion of the inner ring and the contact line portion of the spring member is large in the circumferential direction, thereby improving electrical connectivity.

[0013] In the above configuration 3, a configuration 4 can be adopted in which the spring member includes a twisted wire portion that connects the outer diameter wire portion and the contact wire portion and extends gradually radially inward and axially inward from the outer diameter wire portion to the contact wire portion, and a wound end wire portion that extends radially outward from the opposite side of the contact wire portion to the twisted wire portion, and the wound end wire portion is supported axially by the twisted wire portion at the point of intersection with the axially inward side of the twisted wire portion.

[0014] According to the above configuration 4, the arc-shaped outer diameter portion of the spring member is supported by the groove portion of the outer ring, and the arc-shaped contact portion is supported by the stepped portion of the inner ring. By compressing the spring member in the axial direction so that the torsion portion is deflected axially outward, a spring force can be generated that presses the arc-shaped contact portion against the stepped portion in the axial direction. With this spring force, the opposite side of the torsion portion of the contact portion, which is relatively difficult to press against the stepped portion, can also be firmly pressed against the stepped portion by the support of the torsion portion via the winding end portion.

[0015] In the above configuration 3 or 4, a configuration 5 can be adopted in which spring steel wire is used for the conductive wire, the wire diameter of the conductive wire is φ0.8 mm or more, the outer diameter of the outer diameter wire portion is φ30 mm or more and φ105 mm or less, and the inner diameter of the contact wire portion is φ19 mm or more and φ80 mm or less.

[0016] According to the above configuration 5, it is possible to use a spring member that is formed as a single unit by wire forming, and consequently, the cost of the spring member can be reduced.

[0017] In the above configuration 5, a configuration 6 can be adopted in which the spring steel wire is subjected to a surface treatment to improve its sliding properties.

[0018] According to the above configuration 6, wear of the spring member during operation of the rolling bearing can be prevented.

[0019] As described above, by adopting the above configuration 1, this invention improves the workability of positioning the conductive wire spring member for electrically connecting the outer circumference of the inner ring and the inner circumference of the outer ring between the groove on the inner circumference of the outer ring and the outer circumference of the inner ring.

[0020] A cross-sectional view showing a rolling bearing according to an embodiment of this invention. A left side view showing only the spring member of the rolling bearing shown in Figure 1. A front view showing the spring member before it is installed in the rolling bearing shown in Figure 1. A cross-sectional view of the line IV-IV shown in Figure 2.

[0021] A rolling bearing (hereinafter simply referred to as "this rolling bearing") according to an embodiment of this invention will be described based on the attached drawings.

[0022] The rolling bearing shown in Figure 1 consists of an inner ring 10, an outer ring 20, a plurality of rolling elements 30 arranged between the inner ring 10 and the outer ring 20, a cage 40 that holds these rolling elements 30, and a spring member 50 that electrically connects the outer circumference of the inner ring 10 and the inner circumference of the outer ring 20.

[0023] This rolling bearing is used in environments where a potential difference occurs between the housing H and the shaft S, and is used, for example, to support the motor shaft or the first stage shaft of a reduction gear in an e-Axle or the like relative to the housing.

[0024] The inner ring 10 is a bearing component having a raceway 11 formed on its outer circumference. The outer ring 20 is a bearing component having a raceway 21 formed on its inner circumference. The rolling elements 30 are bearing components that roll on these raceways 11 and 21. The inner ring 10 and the outer ring 20 are mirror-symmetric with respect to a virtual plane that bisects their total width (raceway width).

[0025] The inner ring 10, outer ring 20, and rolling elements 30 are each made of a metal such as steel.

[0026] This rolling bearing is a ball bearing capable of withstanding axial and radial loads, and in the illustrated example, it is configured as a deep groove ball bearing.

[0027] In this rolling bearing, the axial direction refers to the direction along the central axis of the inner ring 10 (not shown; the same applies hereinafter), the radial direction refers to the direction perpendicular to that central axis, and the circumferential direction refers to the direction along the circumference around that central axis. Furthermore, the axial inner direction refers to the direction approaching the raceway, and the axial outer direction refers to the direction away from the raceway. Similarly, the radial inner direction refers to the direction approaching the central axis, and the radial outer direction refers to the direction away from the central axis. Note that Figure 1 shows a state where the central axes of the inner ring 10, outer ring 20, and cage 40 are aligned.

[0028] On the outer circumference of the inner ring 10, a shoulder portion 13, an end portion 14, and a stepped portion 15 are formed in the portion located between the width surface portion 12, which is located at one end of the total width of the inner ring 10 (i.e., the total axial length of the inner ring 10), and the raceway 11. The width surface portion 12 is located at one end (the left end in Figure 1) of the two ends that define the total axial length of the inner ring 10, and is aligned in the radial and circumferential directions. The shoulder portion 13 protrudes radially outward from the end portion 14 between the raceway 11 and the end portion 14. The outer diameter surface of the shoulder portion 13 is cylindrical, defining the outer diameter of the inner ring 10. The end portion 14 has an outer diameter smaller than the outer diameter of the inner ring 10 and is continuous between the shoulder portion 13 and the width surface portion 12. The end portion 14 is set to be between φ19 mm and φ80 mm. The stepped portion 15 is formed on the axially outer side surface of the shoulder portion 13 so as to provide a difference in outer diameter between the outer diameter surface of the shoulder portion 13 and the end portion 14. The starting end of the end 14 on the axially outer side (side of the width surface 12) is chamfered, and the ending end of the end 14 on the axially inner side (side of the raceway 11) is rounded. The stepped portion 15 is composed of a tapered portion that slopes radially outward from the ending end of the end 14 and axially inward, and a chamfered portion that connects this tapered portion to the outer diameter surface of the shoulder portion 13. The inclination angle of the tapered portion is set to be between 60° and 80°. The entire stepped portion 15 is aligned in the circumferential direction. Such an inner ring 10 is common as an inner ring for a sealed bearing in which the seal lip and the outer circumference of the inner ring are in axial contact, and it is possible to reduce the procurement cost of the inner ring 10 by adopting a general specification product for the inner ring 10.

[0029] A shoulder portion 23 and a groove portion 24 are formed in the inner circumference of the outer ring 20, in the portion located between the width surface portion 22, which is located at one end of the total width of the outer ring 20, and the raceway 21. The width surface portion 22 is located at one end (the left end in Figure 1) of the two ends that define the total length of the outer ring 20 in the axial direction, and is aligned in the radial and circumferential directions. The shoulder portion 23 protrudes radially inward from the groove portion 24 between the raceway 21 and the groove portion 24. The inner diameter surface of the shoulder portion 23 is cylindrical, defining the inner diameter of the outer ring 20. The groove portion 24 extends around the entire circumference with a constant groove depth in the radial direction. The axially inner side of the groove portion 24 (raceway 21 side) is continuous with the axially outer side surface of the shoulder portion 23 (width surface portion 22 side). The entire axially outer side surface of both the groove portion 24 and the shoulder portion 23 is aligned in the circumferential direction. The outer diameter of the groove portion 24 is set to be between φ30 mm and φ105 mm. Such an outer ring 20 is a common type of outer ring for sealed bearings that holds the outer circumference of the seal in a groove, and by using a standard specification of this type of outer ring 20, it is possible to reduce the procurement cost of the outer ring 20.

[0030] The spring member 50 is formed from a single conductive wire. Figure 2 shows the left side of the spring member 50 when it is mounted on the rolling bearing as shown in Figure 1, and Figure 3 shows the front view of the spring member 50 in its standalone state before being mounted on the rolling bearing.

[0031] The spring member 50 has an outer diameter line portion 51 that extends in an arc shape along the circumferential direction, a contact line portion 52 that extends in an arc shape along the circumferential direction at a position axially inward from the outer diameter line portion 51, a torsion line portion 53 that connects the outer diameter line portion 51 and the contact line portion 52, and the opposite side of the torsion line portion 53 of the outer diameter line portion 51 (i.e., the half of the outer diameter line portion 51 that is closer to the torsion line portion 53, with the outer diameter line portion 51 bisected in the circumferential direction as the boundary). It is composed of a folded end wire portion 54 that extends radially inward relative to the outer diameter wire portion 51 from the half opposite in the circumferential direction (the half opposite in the circumferential direction of the contact wire portion 52) and a end wire portion 55 that extends from the opposite side of the twisted wire portion 53 of the contact wire portion 52 (that is, the half of the contact wire portion 52 that is circumferentially opposite to the half closer to the twisted wire portion 53, with the circumferential bisecting position of the contact wire portion 52 as the boundary) to a position that intersects axially inward of the twisted wire portion 53. The arc-shaped center of the contact wire portion 52 and the arc-shaped center of the outer diameter wire portion 51 are set on the same axis.

[0032] As shown in Figure 1, the outer diameter wire portion 51 is fitted into the groove portion 24 of the outer ring 20. The outer diameter D1 of the outer diameter wire portion 51 shown in Figure 2 is set to be larger than the inner diameter on the axial side of the groove portion 24, larger than the inner diameter of the outer ring 20, and has a radial interference fit with respect to the groove portion 24, in order to fit the outer diameter wire portion 51 into the groove portion 24 and position it in the axial and radial directions as shown in Figure 1.

[0033] The contact line portion 52 is pressed axially inward against the stepped portion 15 of the inner ring 10 by the spring force of the spring member 50. The inner diameter D2 of the contact line portion 52 shown in Figure 2 is set to be larger than the outer diameter D3 of the end portion 14 so as to create a radial gap between the end portion 14 and the contact line portion 52, without expanding or deforming the contact line portion 52 as shown in Figure 1, and allowing it to contact the stepped portion 15 in the axial direction. In other words, the end portion 14 is continuous between the width surface portion 12 of the inner ring 10 and the stepped portion 15 without having a radial overlap with respect to the spring member 50.

[0034] The twisted wire portion 53 shown in Figures 2 and 3 extends gradually radially inward and axially inward from the outer diameter wire portion 51 to the contact wire portion 52. By connecting the outer diameter wire portion 51 and the contact wire portion 52 with such a twisted wire portion 53, the arc-shaped contact wire portion 52 is positioned axially inward relative to the arc-shaped outer diameter wire portion 51, while also providing an axial compression allowance δ for the spring member 50 between the outer diameter wire portion 51 and the contact wire portion 52. Within this compression range δ, as shown in Figure 1, the arc-shaped outer diameter line portion 51 is supported by the groove portion 24 of the outer ring 20 from both axial sides and radially outward, and the arc-shaped contact line portion 52 is supported axially by the stepped portion 15 of the inner ring 10, and by compressing the spring member 50 in the axial direction so that the torsion line portion 53 is deflected axially outward, it is possible to generate a spring force that presses the arc-shaped contact line portion 52 against the stepped portion 15 in the axial direction, as shown in Figure 1.

[0035] Here, the compression allowance δ in Figure 3 is set so that the contact between the contact line portion 52 and the stepped portion 15 in Figure 1 is always maintained by the aforementioned axial spring force. That is, when a load is applied to this rolling bearing, the inner ring 10 can be displaced axially relative to the outer ring 20 within the range of the axial clearance of the rolling bearing. The compression allowance δ is set so that contact between the contact line portion 52 and the stepped portion 15 can be maintained even when this relative displacement occurs.

[0036] The end wire portion 55 extends radially outward from the opposite side of the contact wire portion 52 from the torsion wire portion 53, and extends to a position where it intersects the axially inward direction of the torsion wire portion 53. As shown in Figures 2 and 4, the end wire portion 55 is in axial contact with the torsion wire portion 53 at the position where it intersects the axially inward direction of the torsion wire portion 53. Therefore, the end wire portion 55 is supported axially by the torsion wire portion 53 at the position of intersection with the torsion wire portion 53. The compression allowance δ in Figure 3 is set so that when the spring member 50 is mounted in a state where it is compressed axially by the compression allowance δ as shown in Figures 1, 2, and 4, contact between the torsion wire portion 53 and the end wire portion 55 at the intersection position is always maintained.

[0037] The end wire portion 55 intersects the axially outer side of the folded end wire portion 54 at a position radially outward from the intersection with the twisted wire portion 53. Since the folded end wire portion 54 is located radially inward from the groove portion 24 of the outer ring 20 shown in Figure 1, it is possible to intersect the end wire portion 55 axially outward with the folded end wire portion 54 without interfering with the inner circumference of the outer ring 20. The axially outer side of the folded end wire portion 54 and the axially inner side of the end wire portion 55 are in contact at the intersection. Since the end wire portion 55 is forcibly bent axially outward from the intersection with the twisted wire portion 53 to the intersection with the folded end wire portion 54, it does not easily slide circumferentially on the folded end wire portion 54.

[0038] Spring steel wire is used as the conductive wire material that forms the spring member 50. The diameter of the spring steel wire material is φ0.8 mm or more. The outer diameter D1 of the outer diameter wire portion 51 is φ105 mm or less. The inner diameter D2 of the contact wire portion 52 is φ19 mm or more. If spring steel wire material with a diameter of φ0.8 mm or more is used, problems such as wire breakage are less likely to occur even if the spring steel wire material is bent or twisted by a wire forming machine. If the outer diameter D1 of the outer diameter wire portion 51 is φ105 mm or less and the inner diameter D2 of the contact wire portion 52 is φ19 mm or more, it is not difficult to process each part of the spring member 50, such as the arc-shaped outer diameter wire portion 51, the arc-shaped contact wire portion 52, and the twisted wire portion 53, in a series using a wire forming machine from spring steel wire material with a diameter of φ0.8 mm or more. In wire forming, the same bending die can be used to process various workpieces as long as the wire diameter and bending radius are suitable. Since there is no need to prepare a dedicated die for each workpiece as with press dies, it is suitable for reducing the manufacturing cost of the spring member 50.

[0039] Furthermore, the aforementioned spring steel wire is subjected to a surface treatment to improve its sliding properties. This surface treatment is intended to prevent wear of the contact line portion 52 caused by sliding contact between the contact line portion 52 of the spring member 50, which is held on the stationary side (housing H side), and the stepped portion 15 of the inner ring 10, which is on the rotating side (shaft S side), during the operation of the rolling bearing shown in Figure 1. It is not necessary to treat the entire surface of the spring member 50; it is sufficient if the treatment is applied to at least the surface portion that makes the aforementioned sliding contact.

[0040] As a surface treatment to improve lubricity, coatings, mechanical treatments, etc., that do not hinder the electrical connection between the inner ring 10 and the outer ring 20 by the spring member 50 can be employed. As a coating, for example, copper plating, silver plating, etc., can be applied to the surface of the spring steel wire to create a treated surface with a lower coefficient of friction compared to the surface of the spring steel wire. As a mechanical treatment, for example, surface modification can be performed to improve lubricant retention by forming countless minute recesses on the surface of the spring steel wire using blasting or the like.

[0041] This rolling bearing (see Figures 1 and 2) is as described above and comprises an inner ring 10, an outer ring 20, a plurality of rolling elements 30 arranged between the inner ring 10 and the outer ring 20, and a spring member 50 that electrically connects the outer circumference of the inner ring 10 and the inner circumference of the outer ring 20. The spring member 50 is formed of a conductive wire, and the inner circumference of the outer ring 20 includes a groove 24 extending in the circumferential direction, and the spring member 50 includes an outer diameter wire portion 51 into which the spring member 50 is fitted in the groove 24, and a contact wire portion 52 that is pressed against the outer circumference of the inner ring 10 by the spring force of the spring member 50.

[0042] In particular, this rolling bearing includes an end portion 14 on the outer circumference of the inner ring 10 that does not have radial interference with respect to the spring member 50, and a stepped portion 15 that protrudes radially outward from the end portion 14. The end portion 14 is continuous between the width surface portion 12 located at one end of the total width of the inner ring 10 and the stepped portion 15. As the contact line portion 52 is pressed axially against the stepped portion 15 by the spring force of the spring member 50, when the outer diameter line portion 51 is elastically deformed radially inward to fit into the groove portion 24, it is not necessary to elastically deform the contact line portion 52 radially outward, but only to pass it over the end portion 14 of the inner ring 10 and press it axially against the stepped portion 15. This makes it easier to position the spring member 50 between the inner circumference of the outer ring 20 and the outer circumference of the inner ring 10. Therefore, this rolling bearing makes it easier to position the conductive wire spring member 50, which electrically connects the outer circumference of the inner ring 10 and the inner circumference of the outer ring 20, between the groove 24 on the inner circumference of the outer ring 20 and the outer circumference of the inner ring 10.

[0043] Furthermore, in this rolling bearing, the contact line portion 52 of the spring member 50 is formed at a position that is axially inward relative to the outer diameter line portion 51. This allows the groove portion 24 of the outer ring 20 and the stepped portion 15 of the inner ring 10 to compress the spring member 50 in the axial direction, generating a spring force that presses the contact line portion 52 against the stepped portion 15. At the same time, this rolling bearing can maintain the pressure of the contact line portion 52 against the stepped portion 15 by following the relative displacement between the inner ring 10 and the outer ring 20 due to the axial clearance of the rolling bearing.

[0044] Further, in this rolling bearing, the outer diameter line portion 51 of the spring member 50 is formed in an arc shape that extends circumferentially along the groove portion 24 of the outer ring 20, and the contact line portion 52 is formed in an arc shape that extends circumferentially along the stepped portion 15 of the inner ring 10. As a result, a large contact length between the groove portion 24 and the outer diameter line portion 51 can be obtained in the circumferential direction, and a large contact length between the stepped portion 15 and the contact line portion 52 can be obtained in the circumferential direction, thereby improving the electrical connectivity between the spring member 50, the inner ring 10, and the outer ring 20.

[0045] Further, this rolling bearing includes a torsion line portion 53 that connects the outer diameter line portion 51 and the contact line portion 52 and extends gradually radially inward and axially inward from the outer diameter line portion 51 to the contact line portion 52, and a curled end line portion 55 that extends radially outward from the opposite side of the torsion line portion 53 of the contact line portion 52. The curled end line portion 55 is axially supported by the torsion line portion 53 at the intersection position with the axially inner side of the torsion line portion 53. By axially compressing the spring member 50 so that the arc-shaped outer diameter line portion 51 is received by the groove portion 24 of the outer ring 20 and the arc-shaped contact line portion 52 is received by the stepped portion 15 of the inner ring 10 to deflect the torsion line portion 53 axially outward, a spring force can be generated to axially press the arc-shaped contact line portion 52 against the stepped portion 15. With this spring force, the opposite side of the torsion line portion 53 of the contact line portion 52, which is relatively difficult to be axially pressed, can also be firmly pressed against the stepped portion 15 by the support of the torsion line portion 53 via the curled end line portion 55.

[0046] Further, in this rolling bearing, a spring steel wire is used as the conductive wire, the wire diameter of the conductive wire is 0.8 mm or more, the outer diameter D1 of the outer diameter line portion 51 is 30 mm or more and 105 mm or less, and the inner diameter D2 of the contact line portion 52 is 19 mm or more and 80 mm or less. Therefore, a spring member 50 formed integrally by wire forming can be adopted, and the manufacturing cost of the spring member 50 can be suppressed. [[ID=​​​​Note that, in this rolling bearing, an example in which it is configured as a deep groove ball bearing has been shown, but it is also possible to change it to other bearing types such as angular ball bearings and self-aligning bearings.

[0049] Also, in this rolling bearing, an example in which an arcuate contact line portion is adopted has been shown, but the contact line portion is not limited to an arcuate shape. For example, it is also possible to form a cantilever beam-shaped contact line portion that extends radially inward at each of one or both circumferential ends of the arcuate outer diameter line portion.

[0050] Also, in this rolling bearing, an example in which a spring member is arranged using the step portion on one end side of the outer circumference of the inner ring and the groove portion on one end side of the inner circumference of the outer ring has been shown. Furthermore, it is also possible to arrange another spring member using the step portion on the other end side of the outer circumference of the inner ring and the groove portion on the other end side of the inner circumference of the outer ring, and change it to a rolling bearing provided with two spring members. In this case, regardless of the relative displacement between the inner ring and the outer ring due to the axial clearance, the axial contact between the contact line portion and the step portion of either one of the spring members will be strengthened. Considering this, it is also possible to relax the compression allowance set for each spring member.

[0051] The embodiments disclosed this time should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is shown not by the above description but by the claims, and it is intended that all modifications within the meaning and scope equivalent to the claims are included.

[0052] 10 Inner ring 12 Width surface portion 14 End portion 15 Step portion 20 Outer ring 24 Groove portion 30 Rolling element 50 Spring member 51 Outer diameter line portion 52 Contact line portion 53 Twisting line portion 55 Coiled end line portion

Claims

1. A rolling bearing comprising an inner ring, an outer ring, a plurality of rolling elements disposed between the inner ring and the outer ring, and a spring member electrically connecting the outer circumference of the inner ring and the inner circumference of the outer ring, wherein the spring member is formed of a conductive wire, the inner circumference of the outer ring includes a groove extending in the circumferential direction, and the spring member includes an outer diameter wire portion fitted into the groove and a contact wire portion pressed against the outer circumference of the inner ring by the spring force of the spring member, wherein the outer circumference of the inner ring includes an end portion that does not have radial overlap with respect to the spring member and a stepped portion protruding radially outward from the end portion, the end portion is continuous between a width surface portion located at one end of the total width of the inner ring and the stepped portion, and the contact wire portion is pressed axially against the stepped portion by the spring force.

2. The rolling bearing according to claim 1, wherein the contact line portion of the spring member is formed at a position that is axially inward with respect to the outer diameter line portion.

3. The rolling bearing according to claim 2, wherein the outer diameter line portion of the spring member is formed in an arc shape extending circumferentially along the groove portion of the outer ring, and the contact line portion is formed in an arc shape extending circumferentially along the stepped portion of the inner ring.

4. The rolling bearing according to claim 3, wherein the spring member includes a torsion wire portion connecting the outer diameter wire portion and the contact wire portion and extending gradually radially inward and axially inward from the outer diameter wire portion to the contact wire portion, and a winding end wire portion extending radially outward from the opposite side of the torsion wire portion of the contact wire portion, the winding end wire portion being axially supported by the torsion wire portion at the position where it intersects with the axially inward side of the torsion wire portion.

5. The rolling bearing according to claim 3 or 4, wherein spring steel wire is used for the conductive wire, the wire diameter of the conductive wire is φ0.8 mm or more, the outer diameter of the outer diameter wire portion is φ30 mm or more and φ105 mm or less, and the inner diameter of the contact wire portion is φ19 mm or more and φ80 mm or less.

6. The rolling bearing according to claim 5, wherein the spring steel wire is subjected to a surface treatment to improve its sliding properties.

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