Energization unit and bearing unit

Abstract

An energization unit (1) has an annular case body (7) that has conductivity, an energization member (8) that has conductivity and that protrudes inward, in the radial direction, from the case body (7), and an elastic member (9) that biases the energization member (8) inward in the radial direction. A guide part (14) for guiding the slide of the energization member (8) in the radial direction is formed in the case body (7), and the bearing unit (A) has the energization unit (1) and the bearing (2).

Description

Current-carrying unit and bearing unit

[0001] The present invention relates to an energizing unit that is attached to a bearing that supports a rotating shaft such as a motor shaft, and to a bearing unit that employs this energizing unit.

[0002] Rolling bearings, especially ball bearings, are commonly used to support rotating shafts such as the motor shaft of an automotive e-axle. In recent years, inverter control has become commonplace for efficient motor operation. In particular, in-vehicle motors are becoming smaller to facilitate installation in vehicles, and more precise control is being implemented to use these smaller motors more efficiently.

[0003] It is known that axial currents and axial voltages occur in this rotating shaft. If this current passes through the inside of the bearing, it can cause electrolytic corrosion in the metal raceways and rolling elements. Therefore, for example, in Patent Document 1 listed below, a sliding brush assembly 25 is provided near a countershaft 3c to which the rotation of the motor shaft 1b is transmitted, and brush contacts 5a protruding from a brush holder 5c of the sliding brush assembly 25 are brought into contact with a shaft end 3c' of the countershaft 3c, thereby dissipating electricity into the housing 3a and preventing the current from passing through the ball bearing 13 (see, for example, Figure 2 of Patent Document 1).

[0004] Patent No. 5573622

[0005] In the configuration of Patent Document 1, a conductive state is ensured by the brush contact 5a coming into contact with a predetermined position on the shaft end 3c'; however, when the motor shaft 1b rotates at high speed, the generation of an oil film, axial eccentricity, vibration, etc. can cause the brush contact 5a (conductive member) to become unstable in its followability and posture relative to the shaft end 3c' (rotating shaft), making it impossible to ensure a stable conductive state and potentially leading to the progression of electrolytic corrosion in the bearing.

[0006] Therefore, an object of the present invention is to provide an energization unit that can ensure a stable energization state, and a bearing unit to which the energization unit is applied.

[0007] In order to solve the above problems, the present invention provides an electrically conductive unit (first configuration) having an annular case body having electrical conductivity, an electrically conductive member protruding radially inward from the case body, and an elastic member that urges the electrically conductive member radially inward, wherein the case body is formed with a guide portion that guides the radial sliding of the electrically conductive member.

[0008] In this configuration, the guide portion smoothly guides the current-carrying member radially inward, allowing the current-carrying member to contact a rotating shaft such as a motor shaft. This ensures a stable current flow between the rotating shaft and the housing, preventing electrolytic corrosion of the bearings provided between the rotating shaft and the housing. Furthermore, since the width surface (particularly the circumferential width surface) of the current-carrying member is guided in the circumferential direction of the current-carrying unit while sliding in the radial direction, the current-carrying member can be stabilized.

[0009] In the first configuration, the case body may have an outer ring portion and a retainer fixed to the outer ring portion (second configuration). When the case body is made up of multiple members in this manner, components such as a conductive member can be smoothly incorporated into the case body.

[0010] In the second configuration, the guide portion may be a groove-shaped recess having a pair of parallel wall surfaces extending radially, and the retainer may have a plurality of guide portions formed at predetermined intervals in the circumferential direction, with the current-carrying member provided on each guide portion (third configuration). In this configuration, the guide portions stabilize the orientation of the current-carrying member, allowing the current-carrying member to be smoothly guided radially. Furthermore, by providing a plurality of current-carrying members, even if the rotating shaft becomes eccentric in one direction due to vibrations caused by its rotation and one current-carrying member is unable to follow the eccentricity, resulting in poor contact, the other current-carrying members arranged in the same direction can maintain electrical conduction. Furthermore, even if the electrical conduction state of one current-carrying member is impaired due to damage or other reasons, the other current-carrying members can compensate for the loss of electrical conduction, ensuring stable electrical conduction performance.

[0011] In the second or third configuration, the retainer may be formed of resin or steel plate (fourth configuration). By making the retainer from resin, sliding properties between the retainer and the current-carrying member can be improved and the weight of the part can be reduced. Furthermore, by making the retainer from steel plate, a current-carrying route through the retainer can be secured.

[0012] In the second to fourth configurations, the retainer may be fixed to the outer annular portion by rivets, spot welds, or press-fitting (fifth configuration), which allows the outer annular portion and the retainer to be easily integrated.

[0013] In the first to fifth configurations, an inclined surface portion inclined toward one side in the axial direction is formed on the outer diameter side end of the current-carrying member, and the current-carrying member is urged axially and contacted with the case main body by the radially inward biasing force of the elastic member abutting on the inclined surface portion (sixth configuration). In this way, the biasing force of the elastic member can be applied not only in the radial direction but also in the axial direction, and this axial biasing force suppresses rattle between the current-carrying member and the guide portion formed on the case main body, thereby reducing the generation of abnormal noise due to vibration and stabilizing the posture of the current-carrying member to ensure good current-carrying performance.

[0014] In the sixth configuration, a spacer that prevents contact between the elastic member and the case main body is provided between the elastic member and the inclined surface portion (seventh configuration). In this way, it is possible to prevent a decrease in the biasing force of the elastic member due to wear caused by repeated contact between the elastic member and the case main body caused by vibrations accompanying high-speed rotation of the bearing.

[0015] In the first to seventh configurations, the current-carrying member may be made of a conductive material such as metal, carbon, or a conductive resin, rubber, ceramic, or a composite of these (eighth configuration), thereby ensuring the current-carrying performance of the current-carrying unit with a simple configuration.

[0016] In the first to eighth configurations, the elastic member may be an annular member provided across the outer diameter ends of the current-carrying members, or a metallic elastic spring interposed between the outer diameter ends of the current-carrying members and the case main body to individually bias the current-carrying members radially inward (a ninth configuration). By providing an annular member across the outer diameter ends of the current-carrying members, the multiple current-carrying members can be collectively biased toward the inner diameter side with a simple configuration. Furthermore, by using a metallic elastic spring as the elastic member that individually biases the current-carrying members radially inward, multiple current-carrying routes can be ensured, including a current-carrying route from the current-carrying members directly to the case main body and a current-carrying route from the current-carrying members to the case main body via the elastic member, thereby achieving more stable current-carrying performance.

[0017] The energizing unit according to all of the above configurations can be employed in a bearing unit having an energizing unit, an outer ring, an inner ring arranged on the inner diameter side of the outer ring, a rolling element provided between the outer ring and the inner ring, and a bearing arranged so that the outer ring abuts against the case main body portion.

[0018] With the current-carrying unit of the present invention and the bearing unit incorporating this current-carrying unit, the guide portion smoothly guides the current-carrying member radially inward, ensuring reliable contact of the current-carrying member with a rotating shaft such as a motor shaft. This ensures a stable current flow between the rotating shaft and the housing, and reliably prevents electrolytic corrosion of the bearings provided between the rotating shaft and the housing.

[0019] 6 is a perspective view of a retainer used in the energizing unit shown in FIG. 5; sectional view of a bearing unit using an energizing unit according to a third embodiment of the present invention; sectional view of a energizing unit according to a fourth embodiment of the present invention; sectional view of a energizing unit according to a fifth embodiment of the present invention; sectional view along line XII-XII in FIG. 11; sectional view showing a modified example of the bearing unit shown in FIG. 1;

[0020] 1 shows a bearing unit A employing a current-carrying unit 1 according to a first embodiment of the present invention. The bearing unit A is composed of the current-carrying unit 1 and a bearing 2 (a ball bearing in this embodiment). The bearing 2 has an outer ring 3, an inner ring 4 disposed on the inner diameter side of the outer ring 3, rolling elements 5 disposed between the outer ring 3 and the inner ring 4, and a cage 6 that holds the rolling elements 5 at predetermined intervals in the circumferential direction.

[0021] 1 and 2 , the current-carrying unit 1 has, as its main components, a case main body 7, a current-carrying member 8, and an elastic member 9. The current-carrying unit 1 is disposed between a motor shaft 10 of an e-axle or the like and a housing 11, adjacent to a bearing 2 that supports the motor shaft 10. The housing 11 is electrically grounded. In the following, the direction along a rotational axis such as the motor shaft 10 is referred to as the axial direction, the direction perpendicular to the rotational axis as the radial direction, and the direction along the circumference around the rotational axis as the circumferential direction.

[0022] The case main body 7 is a conductive annular member fitted into the housing 11. The case main body 7 has an annular outer ring portion 12 having a flange extending in one axial direction at its outer periphery and an extension piece extending radially inward from the outer periphery, and an annular retainer 13 having a flange extending in another axial direction at its outer periphery opposite the one axial direction at its outer periphery and an extension piece extending radially inward from the outer periphery. As shown in Figures 1 and 2 , the outer ring portion 12 and the retainer 13 are integrated by press-fitting a flange formed on the retainer 13 into the inner diameter side of the flange formed on the outer ring portion 12. The integrated outer ring portion 12 and the retainer 13 form a circumferential groove that opens toward the inner diameter side.

[0023] The outer annular portion 12 is formed by pressing a steel plate, and the retainer 13 is formed by injection molding of resin. The size of the axial gap of the circumferential groove formed by integrating the outer annular portion 12 and the retainer 13 is made slightly larger than the axial width of the current-carrying member 8 so that the current-carrying member 8 can move freely in the radial direction.

[0024] Guide portions 14 are formed on the axial surface of the retainer 13 facing the outer ring portion 12, to guide the radial sliding of the current-carrying member 8. The guide portions 14 are made of a pair of block-shaped members extending in the radial direction, and a recessed groove having a pair of parallel wall surfaces along the radial direction is formed on the inside of the block-shaped members. The guide portions 14 are formed at predetermined intervals (90-degree intervals in this embodiment) around the circumferential direction of the retainer 13. Note that this predetermined interval is not limited to this embodiment, and may be, for example, every 60 degrees or 120 degrees in the circumferential direction.

[0025] The current-carrying members 8 are made of conductive material with low volume resistivity, protruding radially inward from the case body 7 and slidingly contacting the motor shaft 10. As shown in FIGS. 2 to 4 , each current-carrying member 8 is housed in a guide portion 14 (in a groove formed by a pair of block-shaped members) formed in the retainer 13. While the number of guide portions 14 and current-carrying members 8 can be varied as needed, it is preferable to provide multiple current-carrying members, as in this embodiment. In this embodiment, the current-carrying members 8 are made of carbon-added polytetrafluoroethylene (PTFE). The inner diameter surface of the current-carrying member 8 is formed as a portion of a cylindrical surface and is in surface contact with the outer periphery of the motor shaft 10. An outer circumferential groove 15 is formed on the outer periphery of the current-carrying member 8.

[0026] As the material for the current-carrying member 8, in addition to carbon-added PTFE, various conductive materials such as metal, carbon, or conductive resin such as carbon-added polyether ether ketone (PEEK), rubber, ceramics, or composites of these may be used. Furthermore, the surface of the current-carrying member 8 (particularly the inner diameter surface that comes into sliding contact with the motor shaft 10) may be subjected to a surface treatment such as a coating (e.g., a conductive diamond-like carbon (DLC) film, a metal film (plating layer, etc.)) that improves electrical conductivity and wear resistance. Note that the conductivity in this application refers to a material having a volume resistivity of 10 ５ The volume resistivity refers to a physical property of Ωcm or less. The volume resistivity can be measured, for example, by the method of JIS K7194.

[0027] The elastic member 9 is provided in a circumferential groove formed in the case body 7, and is a member for biasing the current-carrying members 8 radially inward. As shown in Fig. 2, this elastic member 9 is hung across the circumferential grooves 15 formed in each current-carrying member 8. In this embodiment, a garter spring made of a coiled steel wire processed into a ring shape is used as the elastic member 9, but it is also possible to use, for example, a circlip (C-type retaining ring) with a slit in part of the ring, an annular rubber, or the like.

[0028] The operation of the current-carrying unit 1 will now be described. The motor shaft 10 is inserted through the axis of this current-carrying unit 1. As the motor shaft 10 rotates, the motor shaft 10 and the inner diameter surface of the current-carrying member 8, which is biased toward the motor shaft 10 by the biasing force of the elastic member 9, come into sliding contact with each other, gradually wearing away from the inner diameter surface. Even with this wear, the current-carrying member 8 is always biased toward the motor shaft 10 by the elastic member 9, so the contact state (current-carrying state) between the motor shaft 10 and the current-carrying member 8 is maintained. Furthermore, the current-carrying member 8, which is provided in the guide portion 14 (in the groove), is guided radially without tilting or rattling by a pair of parallel wall surfaces that form the groove in the radial direction.

[0029] The current-carrying unit 1 and bearing unit A according to the first embodiment allow electrical charges generated on a rotating shaft, such as the motor shaft 10, to escape to the housing 11 via the current-carrying member 8 and the case body 7, thereby preventing electrolytic corrosion of the bearing 2 disposed between the motor shaft 10 and the housing 11. Furthermore, the case body 7 is provided with a guide portion 14 that smoothly guides the current-carrying member 8 radially inward without tilting or rattle, allowing the current-carrying member 8 to contact the motor shaft 10. In other words, the current-carrying member 8 is guided radially while its width surface (particularly its circumferential width surface) is guided in the circumferential direction of the current-carrying unit 1, thereby stabilizing its position. This ensures stable current flow between the motor shaft 10 and the housing 11 and more reliably prevents electrolytic corrosion of the bearing 2. Furthermore, the guide portion 14 is a groove-like member having a pair of parallel wall surfaces extending radially, stabilizing the position of the current-carrying member 8 and smoothly guiding it radially.

[0030] Furthermore, in the current-carrying unit 1 according to the first embodiment, the case main body 7 is configured to include the annular outer ring portion 12 and the retainer 13 fixed to the outer ring portion 12, which allows for smooth assembly of components such as the current-carrying member 8 into the case main body 7. Furthermore, the retainer 13 is an injection-molded resin product, which improves sliding properties between the guide portion 14 formed on the retainer 13 and the current-carrying member 8 and also reduces the weight of the component. Furthermore, the outer ring portion 12 and the retainer 13 are configured to be press-fitted and fixed, which allows for easy integration of the outer ring portion 12 and the retainer 13.

[0031] Furthermore, the current-carrying unit 1 according to the first embodiment is configured such that the retainer 13 has a plurality of guide portions 14 formed at predetermined intervals in the circumferential direction, and each guide portion 14 is provided with a current-carrying member 8. Therefore, even if the motor shaft 10 becomes eccentric in one direction due to vibration caused by its rotation and one current-carrying member 8 is unable to follow the eccentricity, resulting in poor contact, the other current-carrying members 8 arranged in the same direction can maintain current flow. Furthermore, even if the current-carrying state of one current-carrying member 8 is impaired due to damage or other reasons, the other current-carrying members 8 can compensate for the loss of current flow, ensuring stable current-carrying performance. Furthermore, since the current-carrying members 8 are made of a conductive material such as metal, carbon, or conductive resin, rubber, ceramics, or a composite of these, the current-carrying performance of the current-carrying unit 1 can be ensured with a simple configuration.

[0032] Furthermore, in the current-carrying unit 1 according to the first embodiment, the elastic member 9 is an annular member that is arranged across the outer peripheral groove 15 formed at the outer diameter end of the plurality of current-carrying members 8, and therefore, the plurality of current-carrying members 8 can be urged collectively toward the inner diameter side with a simple configuration.

[0033] A bearing unit A employing an energization unit 1 according to a second embodiment of the present invention is shown in Figure 5. As shown in Figures 6 to 8, the energization unit 1 according to the second embodiment has the same basic structure as the energization unit 1 according to the first embodiment, but differs in that a press-formed steel plate is used as the retainer 13. The retainer 13 has guide portions 14 formed at predetermined intervals (90-degree intervals in this embodiment) in the circumferential direction. The guide portion 14 has a pair of bent portions bent in the axial direction and a connecting portion connecting the tips of the pair of bent portions, and the pair of bent portions and the connecting portion form a groove having a pair of parallel wall surfaces along the radial direction.

[0034] The outer ring portion 12 and the retainer 13 are fixed by spot welds formed between their respective side surfaces. Note that rivets may be used instead of spot welds. Furthermore, if the retainer 13 has a shape that allows it to fit into the outer ring portion 12, the outer ring portion 12 and the retainer 13 may be press-fitted together, as in the first embodiment.

[0035] Like the current-carrying unit 1 according to the first embodiment, the current-carrying unit 1 according to the second embodiment uses the guide portions 14 to stabilize the position of the current-carrying members 8 and smoothly guide the current-carrying members 8 in the radial direction. In addition, because the retainer 13 is a press-formed product of steel plate, a current-carrying route passing through the retainer 13 can be secured, further improving the reliability of the current-carrying performance of the current-carrying unit 1. Furthermore, by using press forming to process the retainer 13, it is possible to reduce manufacturing costs.

[0036] A third embodiment of the current-carrying unit 1 according to the present invention is shown in Fig. 9. The current-carrying unit 1 according to the third embodiment is similar to the current-carrying unit 1 according to the second embodiment in that it employs a retainer 13 formed from a press-molded steel plate, but differs in that an inclined surface 16 inclined toward one side in the axial direction is formed on the outer diameter side end of the current-carrying member 8. More specifically, this inclined surface 16 is inclined so that the radial dimension of the current-carrying member 8 decreases from the retainer 13 side toward the outer annular portion 12 side.

[0037] As in the first embodiment, elastic members 9 are hung across the inclined surface portions 16 so as to straddle the current-carrying members 8. The biasing force of the elastic members 9 abutting against the inclined surface portions 16 can be broken down into a radial component force f1 acting radially inward and an axial component force f2 acting toward the retainer 13. The current-carrying members 8 are biased toward the motor shaft 10 by the radial component force f1 and toward the retainer 13 by the axial component force f2.

[0038] As with the current-carrying unit 1 according to the second embodiment, the current-carrying unit 1 according to the third embodiment stabilizes the posture of the current-carrying member 8 using the guide portions 14, allowing the current-carrying member 8 to be smoothly guided in the radial direction, and also ensures a current-carrying route via the steel plate retainer 13, thereby further improving the reliability of the current-carrying performance of the current-carrying unit 1. In addition, the axial component force f2 generated when the elastic member 9 abuts against the inclined surface portion 16 suppresses rattle between the current-carrying member 8 and the guide portions 14 formed on the case main body 7, reducing the generation of abnormal noise due to vibration and stabilizing the posture of the current-carrying member 8 to ensure good current-carrying performance.

[0039] In the third embodiment, the retainer 13 is a press-molded product of steel plate, so the inclined surface portion 16 is inclined so that the current-carrying member 8 is urged toward the retainer 13. However, if the retainer 13 is formed by injection molding of resin as in the first embodiment, the inclination direction of the inclined surface portion 16 is reversed, that is, inclined so that the radial dimension of the current-carrying member 8 decreases from the outer ring portion 12 side toward the retainer 13 side. In this way, the axial component force of the elastic member 9 urges the current-carrying member 8 toward the outer ring portion 12, ensuring a current-carrying route that passes through the outer ring portion 12 made of steel plate.

[0040] A fourth embodiment of the energizing unit 1 according to the present invention is shown in FIG. The energizing unit 1 according to the fourth embodiment is similar to the energizing unit 1 according to the third embodiment in that an inclined surface portion 16 is formed on the outer diameter end of the energizing member 8, but differs in that a spacer 17 is provided between the elastic member 9 and the inclined surface portion 16. The inner diameter surface of the spacer 17 is formed with an inclined surface that slopes in the same direction as the inclined surface of the inclined surface portion 16, and the two inclined surfaces are in surface contact. The outer diameter surface is also formed with a retaining groove 18 that holds the elastic member 9, and the elastic member 9 is accommodated in the retaining groove 18. When the elastic member 9 is accommodated in the retaining groove 18, contact between the elastic member 9 and the case main body 7 (outer ring portion 12) is prevented.

[0041] In the fourth embodiment, a spacer 17 is provided between the elastic member 9 and the inclined surface portion 16 to prevent contact between the elastic member 9 and the case main body portion 7 (outer ring portion 12). This prevents wear caused by repeated contact between the elastic member 9 and the case main body portion 7 due to vibrations accompanying high-speed rotation of the motor shaft 10, and prevents a decrease in the biasing force of the elastic member 9.

[0042] 11 and 12 show a fifth embodiment of the current-carrying unit 1 according to the present invention. In the first to fourth embodiments, the elastic member 9 is an annular member provided across the outer diameter side ends of the plurality of current-carrying members 8, whereas in the fifth embodiment, a metallic elastic spring (compression coil spring) is used as the elastic member 9. The elastic member 9 is interposed between the outer diameter side ends of the current-carrying members 8 and the case main body 7 (outer ring portion 12 in this embodiment) and individually biases the current-carrying members 8 radially inward.

[0043] The current-carrying unit 1 of the fifth embodiment uses metal elastic springs as the elastic members 9, which individually bias radially inward. This ensures multiple current-carrying routes, including a current-carrying route in which current flows directly from the current-carrying member 8 to the case main body 7 (outer ring portion 12), and a current-carrying route in which current flows from the current-carrying member 8 to the case main body 7 (outer ring portion 12) via the elastic members 9, thereby enabling more stable current-carrying performance.

[0044] A modified example of the bearing unit A is shown in Figure 13. The bearing unit A according to this modified example shares the basic configuration with the bearing unit A shown in Figure 1, but differs in that whereas the current-carrying unit 1 and the bearing 2 are separate members in this bearing unit A, the flange of the outer ring portion 12 of the current-carrying unit 1 shown in Figure 1 etc. is extended in the axial direction to the outer diameter side of the outer ring 3 of the bearing 2, thereby forming a bearing unit A in which the current-carrying unit 1 and the bearing 2 are integrated. In this way, the same effects as those of the current-carrying unit 1 and bearing unit A shown in Figure 1 can be achieved, and by making the size of the bearing unit A consistent with the main dimensions of bearings standardized in, for example, Japanese Industrial Standards (JIS B1512-1:2011), the weight and width of the bearing unit A including the current-carrying unit 1 can be reduced.

[0045] In each of the above embodiments, the motor shaft 10 is inserted through the axis of the current-carrying unit 1, and the current-carrying member 8 is brought into contact with the motor shaft 10 by being forced radially inward by the elastic member 9. However, conversely, if the motor shaft 10 is provided on the outer diameter side of the current-carrying unit 1 and the housing 11 is provided on the inner diameter side of the current-carrying unit 1, the current-carrying member 8 can also be forced radially outward by the elastic member 9.

[0046] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims.

[0047] DESCRIPTION OF SYMBOLS 1 Current-carrying unit 2 Bearing 3 Outer ring 4 Inner ring 5 Rolling element 7 Case body 8 Current-carrying member 9 Elastic member 12 Outer ring portion 13 Retainer 14 Guide portion 16 Inclined surface portion 17 Spacer A Bearing unit

Claims

1. An energization unit comprising: a conductive annular case body (7); a conductive current-carrying member (8) protruding radially inward from said case body (7); and an elastic member (9) for biasing said current-carrying member (8) radially inward, said case body (7) being provided with a guide portion (14) for guiding the radial sliding of said current-carrying member (8).

2. The current-carrying unit according to claim 1, wherein the case body (7) has an outer ring (12) and a retainer (13) fixed to the outer ring (12).

3. An energizing unit as described in claim 2, wherein the guide portion (14) is a groove-shaped recess having a pair of parallel wall surfaces along the radial direction, a plurality of the guide portions (14) are formed in the retainer (13) at predetermined intervals in the circumferential direction, and the energizing member (8) is provided on each of the guide portions (14).

4. The current-carrying unit according to claim 2, wherein the retainer (13) is made of resin or steel plate.

5. The current-carrying unit according to claim 2, wherein the retainer (13) is fixed to the outer ring portion (12) by any of rivets, spot welding, and press-fitting.

6. An energizing unit as described in claim 1, wherein an inclined surface portion (16) inclined toward one side in the axial direction is formed at the outer diameter side end of the energizing member (8), and the energizing member (8) is urged axially and contacts the case main body portion (7) by the radially inward urging force of the elastic member (9) abutting against the inclined surface portion (16).

7. An energizing unit as described in claim 6, wherein a spacer (17) is provided between the elastic member (9) and the inclined surface portion (16) to prevent contact between the elastic member (9) and the case main body portion (7).

8. The current-carrying unit according to claim 1, wherein the current-carrying member (8) is made of a conductive material such as metal, carbon, or a resin, rubber, ceramics, or a composite of these materials that has been made conductive.

9. An energizing unit as described in claim 3, wherein the elastic member (9) is an annular member provided across the outer diameter end portions of a plurality of the energizing members (8), or a metallic elastic spring interposed between the outer diameter end portions of the energizing members (8) and the case main body portion (7) to individually bias the energizing members (8) radially inward.

10. A bearing unit comprising: an energizing unit (1) according to any one of claims 1 to 9; an outer ring (3); an inner ring (4) arranged on the inner diameter side of the outer ring (3); and a bearing (2) having a rolling element (5) provided between the outer ring (3) and the inner ring (4), the outer ring (3) being arranged so that the outer ring (3) abuts against the case main body (7).

Images