Power supply unit and bearing unit

Abstract

The present invention provides an energizing unit that can stably maintain its electrolytic corrosion prevention effect over a long period of time and can be easily assembled, as well as a bearing unit to which this energizing unit is applied. [Solution] The current-carrying unit 1 comprises a conductive annular outer ring portion 3, a retainer 4 attached to the outer ring portion 3, a conductive current-carrying member 5 held radially movable by the retainer 4 and protruding radially inward from the outer ring portion 3, and a radially elastic member 6 that biases the current-carrying member 5 radially inward, wherein the current-carrying member 5 has a displacement restricting portion 21 formed thereon that restricts its radially inward displacement relative to the retainer 4 to within a predetermined range, and the bearing unit A comprises the above-mentioned current-carrying unit 1 and a bearing 2 having an outer ring 8, an inner ring 9 arranged on the inner diameter side of the outer ring 8, and rolling elements 10 provided between the outer ring 8 and the inner ring 9.

Description

Technical Field

[0001] The present invention relates to a power supply unit provided in a bearing that supports a rotating shaft body such as a motor shaft, and a bearing unit employing this power supply unit.

Background Art

[0002] As a bearing that supports a rotating shaft body such as a motor shaft of an automotive e-axle, a rolling bearing, particularly a ball bearing, is generally used. In recent years, in order to efficiently operate a motor, inverter control is generally adopted. Particularly in the case of an in-vehicle motor, miniaturization is being pursued from the perspective of vehicle mounting, and in order to use the miniaturized motor more efficiently, finer control is being performed.

[0003] It has been found that shaft current and shaft voltage occur in this rotating shaft body. When this current passes through the inside of the bearing, electrical erosion may occur on the raceway ring and rolling elements made of metal. Therefore, for example, in Patent Document 1 below, a sliding brush assembly was provided near the countershaft 3c to which the rotation of the motor shaft 1b is transmitted, and a brush contact 5a protruding from the brush holder 5c of the sliding brush assembly was brought into contact with the shaft end 3c' of the countershaft 3c to release electricity to the housing 3a, so that the current does not pass through the ball bearing 13 (see FIG. etc. of Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] Therefore, the object of the present invention is to provide an energizing unit that can stably maintain an electrolytic corrosion prevention effect over a long period of time and can be easily assembled, and a bearing unit to which the energizing unit is applied. [Means for solving the problem]

[0007] To solve the above problems, the present invention provides: A conductive annular outer ring portion, A retainer attached to the outer ring portion, A conductive current-carrying member is held by the retainer so as to be movable in the radial direction and protrudes radially inward from the outer ring portion, A radially elastic member that biases the current-carrying member radially inward, The energizing unit is configured having a displacement restricting portion formed on the energizing member that restricts its radially inward displacement relative to the retainer to within a predetermined range (first configuration).

[0008] In this configuration, a bypass path for current is newly formed between the housing into which the outer ring fits and the rotating shaft, such as the motor shaft, located at the annular center of the outer ring, thereby suppressing electrolytic corrosion of the bearing components. Furthermore, since a displacement restricting portion is formed on the current-carrying member, the current-carrying member will not fall off towards the inner diameter side due to vibration or shock during or after the assembly of the current-carrying unit, allowing for easy assembly of the unit.

[0009] In the first configuration, the displacement restricting portion is a stepped portion that protrudes axially from the energizing member, and the displacement is restricted by the stepped portion contacting the retainer (second configuration). In this way, the risk of the energizing member falling out toward the inner diameter side can be further reduced by the stepped portion.

[0010] In the second configuration, it is preferable that the amount of axial protrusion of the stepped portion is within the range of 5% to 25% of the axial thickness of the current-conducting member other than the stepped portion (third configuration). This makes it possible to ensure sufficient engagement of the stepped portion with the retainer and to achieve both ease of processing of the current-conducting member.

[0011] In the first to third configurations, the outer ring portion has a cylindrical outer ring portion and an annular plate-shaped flange portion extending radially inward from one axial end of the outer ring portion, and a pair of through holes spaced apart in the circumferential direction are formed in the flange portion, and the retainer is attached to the outer ring portion by fitting a pair of claw portions formed on the retainer into the pair of through holes (fourth configuration). In this way, the retainer can be easily attached to the flange portion of the outer ring portion.

[0012] In the fourth configuration, the retainer is attached from the side of the flange portion opposite to the side on which the current-carrying member is provided, the current-carrying member is held by the claw portion that passes through the through hole, and an axial elastic member is provided in the gap between the current-carrying member and the claw portion to bias the current-carrying member toward the outer ring portion (fifth configuration). In this way, the current-carrying member can be stably held by the retainer, and the current-carrying member is pressed against the outer ring portion by the axial elastic member, thereby ensuring that the current-carrying state between the current-carrying member and the outer ring portion is maintained.

[0013] Furthermore, in the fourth configuration, a space for holding the conductive member is formed in the retainer, and with the conductive member held in the space, an axial elastic member is provided in the gap between the conductive member on the opposite side of the outer ring within the space to bias the conductive member toward the outer ring, and the retainer is attached from the side of the flange portion on which the conductive member is provided (sixth configuration). In this way, in addition to the effects of the fifth configuration, the retainer, conductive member, and axial elastic member can be assembled in advance and then attached to the outer ring, thus greatly improving ease of assembly.

[0014] In configurations 1 through 6, the conductive member may include a conductive material (configuration 7) made of metal, carbon, or a conductive resin, rubber, ceramics, or a composite material thereof. This allows for the assurance of the conductive performance of the conductive unit with a simple configuration.

[0015] In configurations 1 through 7, a configuration (8th configuration) can be provided in which multiple conductive members are arranged along the circumferential direction of the outer ring. In this configuration, even if the rotating shaft becomes eccentric in one direction due to vibrations associated with its rotation, and one conductive member fails to follow the eccentricity, resulting in poor contact, the conductive state is maintained by the other conductive members arranged in the same direction. Moreover, even if the conductive state of one conductive member is impaired due to damage or other reasons, the conductive state can be covered by the other conductive members, thus ensuring stable conductive performance.

[0016] In configurations 1 through 8, the radially elastic member can be an annular member provided across the outer diameter ends of a plurality of current-carrying members, or a metallic elastic spring interposed between the outer diameter ends of the current-carrying members and the outer ring portion to individually bias the current-carrying members radially inward (configuration 9). By providing the annular member across the outer diameter ends of a plurality of current-carrying members in this way, a plurality of current-carrying members can be biased toward the inner diameter in a simple configuration. Furthermore, by employing a metallic elastic spring as the elastic member to individually bias the current-carrying members radially inward, multiple current-carrying routes can be secured, including a current-carrying route in which current flows directly from the current-carrying member to the outer ring portion, and a current-carrying route in which current flows from the current-carrying member to the outer ring portion via the elastic member, thereby enabling more stable current-carrying performance.

[0017] The energizing unit relating to all of the above configurations can be used in a bearing unit having an energizing unit, an outer ring, an inner ring disposed on the inner diameter side of the outer ring, and rolling elements provided between the outer ring and the inner ring. [Effects of the Invention]

[0018] According to the current-carrying unit of the present invention and the bearing unit employing this current-carrying unit, a bypass path for current is newly formed between the housing into which the outer ring portion fits and the rotating shaft body, such as a motor shaft, positioned at the annular center of the outer ring portion. This suppresses electrolytic corrosion of the bearing components. Furthermore, since a displacement-restricting portion is formed on the current-carrying member, the current-carrying member will not fall off to the inner diameter side due to vibration or shock during or after the assembly of the current-carrying unit, allowing for easy assembly of the unit. [Brief explanation of the drawing]

[0019] [Figure 1] Cross-sectional view showing a bearing unit employing the current supply unit according to the first embodiment of the present invention. [Figure 2] Front view of the power supply unit shown in Figure 1. [Figure 3]Front view of the main part of the energization unit shown in Fig. 2 [Figure 4] Cross-sectional view taken along line IV-IV in Fig. 3 [Figure 5] Cross-sectional view taken along line V-V in Fig. 3 [Figure 6] Exploded perspective view of the main part of the energization unit shown in Fig. 2 [Figure 7] Cross-sectional view showing a modified example of the energization unit shown in Fig. 2 [Figure 8] Cross-sectional view taken along line VIII-VIII in Fig. 7 [Figure 9] Front view of the energization unit according to the second embodiment of the present invention [Figure 10] Front view of the main part of the energization unit shown in Fig. 9 [Figure 11] [[ID=2,4]]Cross-sectional view taken along line XI-XI in Fig. 10 [Figure 12] Cross-sectional view taken along line XII-XII in Fig. 10 [Figure 13] Exploded perspective view of the main part of the energization unit shown in Fig. 9 [Figure 14] Exploded perspective view showing a state where some members are pre-assembled in Fig. 13<Q

Mode for Carrying Out the Invention

[0020] A bearing unit A employing the energization unit 1 according to the first embodiment of the present invention is shown in Fig. 1. The bearing unit A is composed of an energization unit 1 and a bearing 2 (a ball bearing in this embodiment). The energization unit 1 has an outer ring portion 3, a retainer 4, an energization member 5, a radial elastic member 6, and an axial elastic member 7. The bearing 2 has an outer ring 8, an inner ring 9 disposed on the inner diameter side of the outer ring 8, rolling elements 10 provided between the outer ring 8 and the inner ring 9, and a cage 11 that holds the rolling elements 10 at predetermined intervals in the circumferential direction.

[0021] This energizing unit 1 is positioned between the rotating shaft 12, such as a motor shaft like an e-axle, and the housing 13, and is located adjacent to the bearing 2 that supports the rotating shaft 12. The housing 13 is electrically grounded. Hereinafter, the direction along the rotating shaft 12 will be referred to as the axial direction, the direction perpendicular to the rotating shaft 12 will be referred to as the radial direction, and the direction along the circumference that makes one full turn around the rotating shaft 12 will be referred to as the circumferential direction.

[0022] A current-carrying unit 1 according to the first embodiment of the present invention will be described with reference to Figures 1 to 6. The outer ring portion 3 of the current-carrying unit 1 is a conductive annular member fitted into the housing 13 and is manufactured by press-forming a steel plate. The outer ring portion 3 has a cylindrical outer ring portion 14 having a surface normal facing radially, and an annular plate-shaped flange portion 15 that extends radially inward from one axial end of the outer ring portion 14 and has a surface normal facing axially, with a hole in the center. The flange portion 15 has a pair of through holes 16 spaced a predetermined distance apart in the circumferential direction, formed at four locations in the circumferential direction (positions corresponding to 0 degrees, 90 degrees, 180 degrees, and 270 degrees in the circumferential direction). Each through hole 16 is an elongated hole shape in which the radial width is slightly longer than the circumferential width. The number of pairs of through holes 16 is not limited to this embodiment and can be appropriately determined in accordance with the number of current-carrying members 5.

[0023] The retainer 4 is a component attached to the outer ring portion 3 while holding the current-carrying member 5 and the axially elastic member 7, and is formed by injection molding of resin. The retainer 4 of the current-carrying unit 1 according to the first embodiment has a substantially U-shape in plan view and has a base portion 17 that extends so as to straddle a pair of through holes 16 formed in the flange portion 15, extension portions 18 that extend axially from both ends of the base portion 17 and are inserted into the pair of through holes 16, and claw portions 19 that extend from the tips of both extension portions 18 in directions opposite to each other. The radial width of the extension portion 18 is smaller than the radial width of the through holes 16 formed in the flange portion 15, and the retainer 4 can move slightly relative to the outer ring portion 3 in the radial direction. Slits 20 are formed in the inner base portion of the claw portions 19 formed on the retainer 4 for holding the ends of the axially elastic member 7. The retainer 4 is attached from the side of the flange portion 15 opposite to the side on which the current-carrying member 5 is provided.

[0024] The conductive member 5 is held radially movable by the retainer 4 and is a conductive member that protrudes radially inward from the outer ring portion 3 and slides against the rotating shaft body 12. The conductive member 5 has a displacement restricting portion 21 that restricts its radially inward displacement relative to the retainer 4 to within a predetermined range (a range in which the conductive member 5 does not fall off to the inner diameter side). The conductive member 5 of the conductive unit 1 according to the first embodiment has a base portion 22 that extends along the circumferential direction and a stepped portion (hereinafter, the same reference numeral as the displacement restricting portion 21) that is formed to protrude axially from the base portion 22.

[0025] The axial protrusion amount D of the stepped portion 21 is within the range of 5% to 25% of the axial thickness W of the conductive member 5 other than the stepped portion 21, preferably within the range of 10% to 25%, more preferably within the range of 15% to 25%, and in this embodiment, it is 20%. If the axial protrusion amount D of the stepped portion 21 is less than 5% of the axial thickness W of the conductive member 5 other than the stepped portion 21, the engagement between the stepped portion 21 and the retainer 4 may easily disengage, making it difficult to obtain a sufficient displacement restriction effect. If it is greater than 25%, the difficulty of machining the retainer 4 increases, so it is preferable to keep it within the above range.

[0026] In this embodiment, carbon-added polyether ether ketone (PEEK) is used as the material for the conductive member 5. The inner diameter surface of the conductive member 5 is composed of a part of the cylindrical surface and is in surface contact with the outer circumferential surface of the rotating shaft 12. An outer circumferential groove 23 is formed on the outer edge of the conductive member 5. The number of conductive members 5 can be determined as appropriate, but it is preferable to use multiple members as in this embodiment.

[0027] As the material for the conductive member 5, in addition to carbon-added PEEK, various conductive materials can be used, such as metal, carbon, or resins, rubber, ceramics, or composites thereof that have been imparted with conductivity, such as carbon-added polytetrafluoroethylene (PTFE). Here, carbon refers to materials whose main structure is carbon bonds, such as carbon nanofibers, carbon fibers, carbon nanotubes, and graphite. Furthermore, the surface of the conductive member 5 (especially the inner diameter surface that slides against the rotating shaft 12) can be treated with a coating to improve conductivity and wear resistance (for example, a conductive diamond-like carbon (DLC) film, a metal film (plating layer, etc.)). In this application, conductivity refers to a volume resistivity of 10⁻¹⁰ 5 This refers to physical properties of Ωcm or less. Volume resistivity can be measured, for example, by the method specified in JIS K7194.

[0028] The conductive member 5 is provided between a pair of extensions 18 extending from both ends of the base 17 of the retainer 4. When the biasing force of the radial elastic member 6 is applied, the claw portion 19 formed on the retainer 4 abuts against the radially inner portion of the stepped portion 21 formed on the conductive member 5, thereby restricting the displacement of the conductive member 5 toward the inner diameter. An axial elastic member 7 is held in a slit 20 formed in the inner base portion of the claw portion 19 formed on the retainer 4 (the axial gap between the conductive member 5 and the claw portion 19). The axial elastic member 7 is a member for biasing the conductive member 5 toward the outer ring portion 3. In this embodiment, a leaf spring is used as the axial elastic member 7, but other elastic members can also be used.

[0029] The radially elastic member 6 is a member for biasing the conductive member 5 radially inward. This radially elastic member 6 is stretched across the outer circumferential groove 23 formed in each conductive member 5. In this embodiment, a garter spring made by processing a coiled steel wire into a ring shape is used as the radially elastic member 6, but for example, a circlip (C-type retaining ring) with a slit in part of the ring or an annular piece of rubber can also be used.

[0030] The operation of the energizing unit 1 will now be explained. A rotating shaft 12, such as a motor shaft, is inserted through the axis of this energizing unit 1. When the inner diameter surface of the energizing member 5, which is biased toward the rotating shaft 12 by the biasing force of the radial elastic member 6, comes into sliding contact with the rotating shaft 12, this inner diameter surface gradually wears down. However, since the energizing member 5 is always biased toward the rotating shaft 12 by the radial elastic member 6, the contact state (energetic state) between the rotating shaft 12 and the energizing member 5 is maintained.

[0031] In the first embodiment, the energizing unit 1 and bearing unit A are configured to dissipate the electric charge generated on the rotating shaft 12 to the housing 13 via the energizing member 5 and the outer ring portion 3, thereby preventing electrolytic corrosion of the bearing 2 provided between the rotating shaft 12 and the housing 13. Moreover, since the energizing member 5 has a displacement restricting portion 21 (step portion 21) formed on it, the energizing member 5 does not fall off to the inner diameter side due to vibration or shock during or after the assembly of the energizing unit 1, allowing for easy assembly of the energizing unit 1.

[0032] Furthermore, in the energizing unit 1 according to the first embodiment, since the retainer 4 is made of resin injection molded product, both extended portions 18 can be easily inserted into the pair of through holes 16 by bending the retainer 4, and the retainer 4 can be stably held in the state where both extended portions 18 are inserted into the through holes 16. In addition, the sliding properties between the retainer 4 and the outer ring portion 3 can be improved, and the weight can be reduced.

[0033] Furthermore, in the energizing unit 1 according to the first embodiment, since the energizing member 5 is biased toward the outer ring portion 3 by the axial elastic member 7, a good energizing state can be ensured between the energizing member 5 and the outer ring portion 3.

[0034] Furthermore, in the energizing unit 1 according to the first embodiment, since multiple energizing members 5 are provided along the circumferential direction of the outer ring portion 3, even if the rotating shaft 12 becomes eccentric in one direction due to vibrations associated with its rotation, and one energizing member 5 fails to follow the eccentricity and causes poor contact, the energizing state is maintained by the other energizing members 5 arranged in the same direction. Moreover, even if the energizing state of one energizing member 5 is impaired due to damage or the like, the other energizing members 5 can cover the energizing state, thus ensuring stable energizing performance. In addition, since the energizing members 5 include conductive materials composed of metal, carbon, or conductive resin, rubber, ceramics, or composite materials thereof, the energizing performance of the energizing unit 1 can be ensured with a simple configuration.

[0035] Furthermore, in the energizing unit 1 according to the first embodiment, the radially elastic member 6 is an annular member provided across the outer peripheral groove 23 formed at the outer diameter end of a plurality of energizing members 5, so that a plurality of energizing members 5 can be biased toward the inner diameter side all at once with a simple configuration.

[0036] In the above, an annular garter spring provided across the outer circumferential grooves 23 of multiple current-carrying members 5 was used as the radial elastic member 6. However, as shown in the modified examples in Figures 7 and 8, a metal elastic spring (compression coil spring) can also be used as the radial elastic member 6, interposed between the outer diameter end of the current-carrying member 5 and the outer ring portion 3 to individually bias the current-carrying members 5 radially inward.

[0037] According to this modified current-carrying unit 1, multiple current-carrying routes can be secured, including a current-carrying route in which current flows directly from the current-carrying member 5 to the outer ring portion 3, and a current-carrying route in which current flows from the current-carrying member 5 to the outer ring portion 3 via the radially elastic member 6, thereby enabling more stable current-carrying performance.

[0038] A current-carrying unit 1 according to a second embodiment of the present invention will be described with reference to Figures 9 to 14. The current-carrying unit 1 according to the second embodiment is similar to the current-carrying unit 1 according to the first embodiment in that it has an outer ring portion 3, a retainer 4, a current-carrying member 5, a radially elastic member 6, and an axially elastic member 7, but the configuration of the retainer 4 and the current-carrying member 5 is different. The differences will be described below.

[0039] The retainer 4 of the energizing unit 1 according to the second embodiment has a base portion 17 that extends across a pair of through holes 16 formed in the flange portion 15, extension portions 18 that extend radially inward from both ends of the base portion 17, and claw portions 19 (first claw portion 19a and second claw portion 19b) that extend in opposing directions from the tips of both extension portions 18. The flat surface on the inner diameter side of the base portion 17, as well as the inner surfaces of the extension portions 18, the first claw portion 19a, and the second claw portion 19b, form a space for holding the energizing member 5. An outer peripheral groove 23 is formed on the outer peripheral edge of the base portion 17.

[0040] The first claw portion 19a is a claw for holding the conductive member 5 together with the axial elastic member 7, and the second claw portion 19b is a claw for attaching the retainer 4 to the outer ring portion 3. Slits 20 are formed in the inner base portion of the first claw portion 19a for holding the ends of the axial elastic member 7. The retainer 4 is attached from the side of the flange portion 15 where the conductive member 5 is provided.

[0041] The current-carrying member 5 of the current-carrying unit 1 according to the second embodiment has a base portion 22 extending along the circumferential direction and a stepped portion 21 as a displacement restricting portion 21 formed to protrude axially from the base portion 22. The amount of axial protrusion D of the stepped portion 21 is within the range of 5% to 25% of the axial thickness W of the current-carrying member 5 other than the stepped portion 21, preferably within the range of 10% to 25%, more preferably within the range of 15% to 25%, and in this embodiment it is 20%. Also, as with the first embodiment, carbon-added polyetheretherketone (PEEK) is used as the material for the current-carrying member 5. The inner diameter surface of the current-carrying member 5 is composed of a part of a cylindrical surface and is in surface contact with the outer circumferential surface of the rotating shaft body 12. The outer circumferential edge of the current-carrying member 5 is a flat surface.

[0042] The conductive member 5 is provided within the space formed in the retainer 4 such that the flat surface on the inner diameter side of the base 17 of the retainer 4 and the flat surface on the outer edge of the conductive member 5 are in surface contact. At this time, the first claw portion 19a formed in the retainer 4 abuts against the radially inner portion of the stepped portion 21 formed in the conductive member 5, thereby restricting the displacement of the conductive member 5 toward the inner diameter side. An axial elastic member 7 is held in the slit 20 formed in the inner base portion of the first claw portion 19a formed in the retainer 4 (the axial gap between the conductive member 5 and the first claw portion 19a). The axial elastic member 7 is a leaf spring, as in the first embodiment.

[0043] As shown in Figure 14, the energizing unit 1 according to the second embodiment can be attached to the outer ring portion 3 after the retainer 4, energizing member 5, and axial elastic member 7 have been pre-assembled. Therefore, in addition to the effects and advantages of the energizing unit 1 according to the first embodiment, the ease of assembly can be greatly improved.

[0044] Furthermore, in the second embodiment, the current-carrying unit 1 has an outer circumferential groove 23 formed on the retainer 4, which can be easily molded by resin injection molding, while the shape of the current-carrying member 5, which is relatively more difficult to process than the retainer 4, has been simplified, which may reduce processing costs.

[0045] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than by the foregoing description, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Explanation of Symbols]

[0046] 1 Power supply unit 2 bearings 3 Outer ring 4 Retainer 5. Conductive components 6. Radial elastic member 7. Axial elastic member 8 Outer ring 9 Inner ring 10 Rolling elements 14 Outer ring portion 15 Flange section 16 Through holes 19. Nail area 21 Displacement restricting section (step section) A Bearing Unit D Axial protrusion amount W axial thickness

Claims

1. An annular outer ring portion (3) having conductivity, A retainer (4) attached to the outer ring portion (3), A conductive current-carrying member (5) is held radially movable by the retainer (4) and protrudes radially inward from the outer ring portion (3), A radially elastic member (6) biases the current-carrying member (5) radially inward, An energizing unit having a displacement restricting portion (21) formed on the energizing member (5) that restricts its radially inward displacement relative to the retainer (4) to within a predetermined range.

2. The current-carrying unit according to claim 1, wherein the displacement restricting portion (21) is a stepped portion (21) that protrudes in the axial direction and is formed on the current-carrying member (5), and the displacement is restricted by the stepped portion (21) contacting the retainer (4).

3. The energizing unit according to claim 2, wherein the amount of axial protrusion (D) of the stepped portion (21) is within the range of 5% to 25% of the axial thickness (W) of the energizing member (5) other than the stepped portion (21).

4. The outer ring portion (3) has a cylindrical outer ring portion (14) and an annular plate-shaped flange portion (15) extending radially inward from one axial end of the outer ring portion (14), The energizing unit according to claim 1, wherein a pair of circumferentially spaced through holes (16) are formed in the flange portion (15), and the retainer (4) is attached to the outer ring portion (3) by fitting a pair of claw portions (19) formed on the retainer (4) into the pair of through holes (16).

5. The current-carrying unit according to claim 4, wherein the retainer (4) is attached from the side of the flange portion (15) opposite to the side on which the current-carrying member (5) is provided, the current-carrying member (5) is held by the claw portion (19) passing through the through hole (16), and an axial elastic member (7) is provided in the gap between the current-carrying member (5) and the claw portion (19) to bias the current-carrying member (5) toward the outer ring portion (3).

6. A space for holding the conductive member (5) is formed in the retainer (4), and while the conductive member (5) is held in the space, an axial elastic member (7) is provided in the gap between the conductive member (5) on the opposite side of the outer ring portion (3) within the space, which biases the conductive member (5) toward the outer ring portion (3). The current-carrying unit according to claim 4, wherein the retainer (4) is attached from the side of the flange portion (15) on which the current-carrying member (5) is provided.

7. The current-carrying unit according to claim 1, wherein the current-carrying member (5) includes a conductive material composed of metal, carbon, or a conductive resin, rubber, ceramics, or a composite material thereof.

8. The current-carrying unit according to claim 1, wherein a plurality of the current-carrying members (5) are provided along the circumferential direction of the outer ring portion (3).

9. The current-carrying unit according to claim 8, wherein the radially elastic member (6) is an annular member provided across the outer diameter ends of a plurality of current-carrying members (5), or a metallic elastic spring interposed between the outer diameter ends of the current-carrying members (5) and the outer ring portion (3) to individually bias the current-carrying members (5) radially inward.

10. A power supply unit (1) according to any one of claims 1 to 9, A bearing (2) having an outer ring (8), an inner ring (9) positioned on the inner diameter side of the outer ring (8), and rolling elements (10) provided between the outer ring (8) and the inner ring (9), A bearing unit having

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