Rolling bearing holder

Abstract

The invention provides a retainer for a rolling bearing. Lubricating oil introduced into the bearing is retained, and oil cut-off does not occur even under harsh operating conditions. A cage for a rolling bearing provided with an outer ring (1), an inner ring (2), and a plurality of balls (3) disposed between the outer ring (1) and the inner ring (2), the cage being provided with an annular portion (21), a plurality of pillar portions (22) protruding from the annular portion (21) in the axial direction of the bearing, and pockets (23) for holding the balls (3), the pockets (23) being formed between the pillar portions (22, 22) adjacent to each other in the circumferential direction of the bearing, the radius of the arc of the radial inner peripheral surface (D) of the pocket (23) in a cross section passing through the pocket center (p) of the pocket (23) and including the bearing center line (o) is set to be less than 1 / 2 of the diameter [phi] x of the ball (3) over the entire region of the radial inner peripheral surface (D).

Description

Technical Field

[0001] The present invention relates to a cage for a rolling bearing and a rolling bearing having the cage. Background Art

[0002] For example, in various vehicles such as automobiles and construction machinery, and various other industrial machinery, many rolling bearings are used in motor shafts of transmissions (speed reducers) and the like that drive motors. Rolling bearings used in the above-mentioned equipment are generally used under high-speed conditions compared to bearings used for shaft support in ordinary equipment.

[0003] In addition, in ball bearings using balls as rolling elements, a resin crown-shaped retainer is often used. The crown-shaped retainer has an annular portion and a plurality of columnar portions (protruding portions) protruding from the annular portion toward the axial direction of the bearing, and the protruding side ends of the columnar portions usually serve as claws for retaining the balls.

[0004] However, in rolling bearings used under high-speed conditions in electric vehicles, etc., it is considered to promote the lower viscosity of lubricating oil in the future. Therefore, it is expected that the oil film formed between the retainer and the rolling element will be more difficult to form than it is now. Even in such a harsh environment, it is particularly important to set an oil reservoir on the inner surface of the retainer to retain the oil.

[0005] In Patent Document 1, a through groove is provided from the annular portion of the crown-shaped retainer to the inner surface of the pocket, so that the lubricating oil adhering to the annular portion can flow directly into the inner surface of the pocket, thereby preventing the lack of oil between the rolling elements and the occurrence of seizure and wear even in a high-speed rotation environment.

[0006] Patent Document 1: Japanese Patent Application Publication No. 2022-164434

[0007] In Patent Document 1, the lubricating oil adhering to the annular portion of the retainer can flow into the inner surface of the pocket through the through groove. However, the inflowing lubricating oil cannot be stored around the retainer or inside the bearing, and is actively discharged to the outside of the bearing. Therefore, when the ratio of the lubricating oil discharged is greater than the inflow, there is a possibility that the oil film between the retainer and the rolling element will break, causing sintering and wear. In particular, when the amount of lubricating oil supplied is small, and under thin lubrication in which less lubricating oil passes through the bearing due to high-speed rotation, this tendency is considered to become more significant. Summary of the invention

[0008] Therefore, an object of the present invention is to retain the lubricating oil introduced into the bearing so as to prevent oil shortage even under severe operating conditions.

[0009] In order to solve the above-mentioned problems, the present invention adopts the following retainer, which is used for a rolling bearing, the rolling bearing comprising an outer ring and an inner ring, and a plurality of balls arranged between the outer ring and the inner ring, the retainer comprising an annular portion and a plurality of column portions protruding axially from the annular portion toward the bearing, and comprising pockets for retaining the balls, the pockets being formed between the column portions adjacent to each other along the circumferential direction of the bearing, wherein the radius of the arc of the radial inner circumferential surface of the pocket in a cross section passing through the center of the pocket and including the center line of the bearing is set to be less than 1 / 2 of the diameter φx of the balls over the entire area of ​​the radial inner circumferential surface (Structure 1).

[0010] In a method having structure 1, the following structure can be adopted: the above-mentioned radial inner circumferential surface is consistent with an imaginary line formed by an ellipse having a radial pocket short diameter smaller than the diameter φx of the above-mentioned ball in the radial direction of the bearing and an axial pocket long diameter larger than the diameter φx of the above-mentioned ball in the axial direction of the bearing (structure 2).

[0011] In addition, in a method having structure 1, or a method having structure 1 and structure 2, the following structure can be adopted: the radius of the arc of the circumferential inner surface of the above-mentioned pocket in a cross section passing through the center of the above-mentioned pocket and orthogonal to the center line of the bearing is set to be smaller than 1 / 2 of the diameter φx of the above-mentioned ball over the entire area of ​​the above-mentioned circumferential inner surface (Structure 3).

[0012] In the embodiment having structure 3, the following structure can be adopted: the circumferential inner surface of the pocket in a cross section passing through the center of the pocket and orthogonal to the center line of the bearing is consistent with an imaginary line formed by an ellipse having a radial pocket short diameter smaller than the diameter φx of the ball in the radial direction of the bearing and a circumferential pocket long diameter larger than the diameter φx of the ball in the tangential direction relative to the circumference of the bearing (structure 4).

[0013] Here, in the embodiment including the configuration 1 and the configuration 2, a configuration can be adopted in which the ratio of the radial pocket minor diameter to the axial pocket major diameter is 0.83 or more and less than 0.97 (configuration 5).

[0014] In the embodiment including the configuration 4, a configuration can be adopted in which the ratio of the radial pocket minor diameter to the circumferential pocket major diameter is equal to or greater than 0.83 and less than 0.97 (configuration 6).

[0015] In addition, in a method having structure 1, the following structure can be adopted: the above-mentioned radial inner circumferential surface is consistent with an imaginary line formed by an ellipse having a radial pocket short diameter smaller than the diameter φx of the ball in the radial direction of the bearing and an axial pocket long diameter larger than the diameter φx of the ball in the axial direction of the bearing, the circumferential inner circumferential surface of the above-mentioned pocket in a cross section passing through the center of the above-mentioned pocket and orthogonal to the center line of the bearing is consistent with an imaginary line formed by an ellipse having a radial pocket short diameter smaller than the diameter φx of the ball in the radial direction of the bearing and a circumferential pocket long diameter larger than the diameter φx of the ball in a tangential direction relative to the circumferential direction of the bearing, and the center of the ellipse of the above-mentioned imaginary line of the above-mentioned radial inner circumferential surface and the center of the ellipse of the above-mentioned imaginary line of the above-mentioned circumferential inner circumferential surface are consistent with each other (structure 7).

[0016] In a method having structure 1, or in a method in which a single or multiple elements selected from structures 2 to 7 are added to structure 1, the following structure can be adopted: the radius of the arc of the above-mentioned radial inner circumferential surface is greater than 0.86 and less than 0.98 relative to 1 / 2 of the diameter φx of the above-mentioned ball over the entire area of ​​the above-mentioned radial inner circumferential surface (Structure 8).

[0017] In addition, in a method having structure 1, or in a method in which a single or multiple elements selected from structures 2 to 8 are added to structure 1, the following structure can be adopted: the outer diameter surfaces of the retainers of the above-mentioned annular portion and the above-mentioned column portion are inclined in the inner diameter direction as they move from the side of the above-mentioned annular portion toward the protruding end side of the above-mentioned column portion (structure 9).

[0018] A bearing device can be used that uses a rolling bearing having the above-mentioned structure 1, or adds a retainer having one or more elements selected from structures 2 to 9 to structure 1, for supporting a motor shaft or a reducer shaft that transmits the driving force of a driving motor for an automobile (structure 10).

[0019] According to the present invention, the lubricating oil introduced into the bearing can be retained, and oil shortage will not occur even under severe operating conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a front view showing one embodiment of the present invention.

[0021] Figure 2 yes Figure 1 II-II sectional view.

[0022] Figure 3 It is a cross-sectional view showing a main part of the retainer.

[0023] Figure 4 yes Figure 3 IV-IV cross-sectional view.

[0024] Figure 5 It is a cross-sectional view showing a main part of the retainer.

[0025] Figure 6 It is a cross-sectional view showing a modified example of the cage.

[0026] Description of Reference Numerals

[0027] 1…outer ring; 2…inner ring; 3…ball (rolling element); 10…rolling bearing (ball bearing); 20…cage; 21…annular portion; 21a…end face of cage; 22…column portion (protrusion); 22a…claw portion; 23…pocket; 24…inner diameter face of cage; 25…outer diameter face of cage; a…radial pocket short diameter; b…circumferential pocket long diameter; c…axial pocket long diameter; D…radial inner peripheral surface; E…circumferential inner peripheral surface; F…bottom; G…front end; H…recess; J…side center point; o…bearing center line; p…pocket center; R…imaginary line. DETAILED DESCRIPTION

[0028] An embodiment of the present invention is described based on the accompanying drawings. This embodiment is a rolling bearing 10 that supports the rotating shaft of a drive motor of an electric transportation device such as an electric vehicle, or the rotating shaft of a speed reducer or speed increaser of the electric transportation device, a bearing device used for the rolling bearing 10 to support the shaft, and a retainer 20 used for the rolling bearing 10.

[0029] like Figure 1 and Figure 2 As shown, the rolling bearing 10 includes: an outer ring 1 and an inner ring 2; a plurality of rolling elements 3 arranged between the outer ring 1 and the inner ring 2; and a retainer 20 having pockets 23 for retaining the rolling elements 3 along the circumferential direction. Since spherical bodies (steel balls) are used as the rolling elements 3, they are hereinafter referred to as balls 3. In addition, the rolling bearing 10 is hereinafter referred to as simply a bearing 10. In addition, the direction along the bearing center line o of the bearing 10 is referred to as the "axial direction of the bearing" or simply the "axial direction", the direction orthogonal to the axial direction is referred to as the "radial direction of the bearing" or simply the "radial direction", and the circumferential direction around the bearing center line o is referred to as the "circumferential direction of the bearing" or simply the "circumferential direction".

[0030] The retainer 20 is a crown-shaped retainer formed of engineering plastic. The retainer 20 includes a ring portion 21 forming a ring shape, and a plurality of column portions 22 protruding axially from the ring portion 21. The column portions 22 are arranged at constant intervals along the circumferential direction. A concave pocket 23 for retaining the ball 3 is formed between two circumferentially adjacent column portions 22. The outer diameter surface of the retainer 20 (retainer outer diameter surface 25) is preferably a curved surface (cylindrical surface or conical surface) without a step difference. The outer diameter surface and the inner diameter surface of the retainer 20 are connected in the pocket 23. In addition, as a material for the retainer 20, for example, polyamide resin (PA46, PA66, PA9T, etc.) and polyphenylene sulfide resin (PPS) are preferred.

[0031] The protruding side ends of the column 22 serve as retaining claws 22a. The retaining claws 22a, 22a on both sides of the pocket 23 are bent toward each other. In addition, between the pockets 23 and the pockets 23 adjacent to each other in the circumferential direction, the adjacent column 22, 22 may be connected to each other. The ball 3 held by the pocket 23 revolves between the raceway surface 1a of the outer ring 1 and the raceway surface 2a of the inner ring 2 while being held by the pocket 23.

[0032] The inner ring 2 is fixed to an unillustrated shaft at its inner diameter portion 2b and rotates integrally with the shaft in the circumferential direction. The outer ring 1 is mounted on a housing, gear or other component not shown in the figure, and is a fixed component that bears the load from the shaft. Thus, the bearing 10 supports the shaft so that it can rotate freely relative to the fixed component. As the shaft mentioned here, for example, there can be cited the rotating shaft of a drive motor equipped in an electric transportation device such as an electric vehicle, or the rotating shaft of a reducer or speed increaser equipped in the above-mentioned electric transportation device. In addition, the bearing center axis of the bearing 1 is set to be coaxial with the rotation center axis of the rotating shaft.

[0033] Here, if Figure 3 As shown, the radius of the arc of the radial inner circumferential surface D of the pocket 23 in the longitudinal section (radial section) passing through the pocket center p of the pocket 23 and including the bearing center line o is set to be less than 1 / 2 of the diameter φx of the ball 3 in the entire area of ​​the radial inner circumferential surface D. Therefore, a gap in which the pocket 23 and the ball 3 do not contact is generated between the inner diameter side end d1 and the outer diameter side end d2 of the radial inner circumferential surface D, and the lubricating oil can be retained (stored) in the gap. In addition, the lubricating oil can also be discharged along the circumferential direction. Thus, oil shortage can be prevented even under thin lubrication. The method for measuring the pocket center p can use a three-dimensional measuring instrument as a measuring device. Measuring method: In the present invention, the curved surface of the pocket of the object is measured by a three-dimensional measuring machine. As measuring points, the inner circumference and the outer circumference of the retainer are measured respectively (imagine Figure 3 , Figure 4 Multi-point (4 or more) measurements are performed (near the perfect circle in contact with the surface), and the center point of the imaginary sphere derived from the results is set to p.

[0034] In addition, Figure 3 to Figure 5 In order to facilitate understanding, the difference in diameter (radius) of each arc and the positional relationship of the center of the arc are exaggeratedly drawn.

[0035] In the present embodiment, the radial inner peripheral surface D coincides with an imaginary line R formed by an ellipse having a radial pocket minor diameter a smaller than the diameter φx of the ball 3 in the radial direction of the bearing and an axial pocket major diameter c larger than the diameter φx of the ball 3 in the axial direction of the bearing. Since the ellipse has the largest curvature (small curve radius) near the intersection with the major diameter, the intersection with the major diameter near the large curvature and the perfect circle of the ball 3 are opposed, thereby ensuring a larger gap between the inner diameter side end d1 and the outer diameter side end d2 of the radial inner peripheral surface D.

[0036] In addition, if Figure 4 As shown in FIG. 1 , the radius of the arc of the circumferential inner peripheral surface E of the pocket 23 in the cross section passing through the pocket center p and orthogonal to the bearing center line o is set to be smaller than 1 / 2 of the diameter φx of the ball 3 in the entire area of ​​the circumferential inner peripheral surface E. Therefore, as in the case of the radial inner peripheral surface D, a gap is generated between the inner diameter side end and the outer diameter side end of the circumferential inner peripheral surface E where the pocket 23 and the ball 3 do not contact, and the lubricating oil can be retained (stored) in the gap.

[0037] In the present embodiment, the circumferential inner surface E coincides with an imaginary line R formed by an ellipse having a radial pocket minor diameter a smaller than the diameter φx of the ball 3 in the radial direction of the bearing and having a circumferential pocket major diameter b larger than the diameter φx of the ball 3 in the tangential direction relative to the circumferential direction of the bearing. Similarly, the vicinity of the intersection of the major diameter with the large curvature faces the perfect circle of the ball 3, thereby ensuring a larger gap between the inner diameter side end and the outer diameter side end of the circumferential inner surface E.

[0038] Here, the pocket center p coincides with the center of the ball 3 by design. In addition, the centers of the ellipse of the imaginary line R of the radial inner circumferential surface D and the ellipse of the imaginary line R of the circumferential inner circumferential surface E coincide with each other. However, it is also conceivable to make the center of the ellipse of the imaginary line R of the radial inner circumferential surface D and the center of the ellipse of the imaginary line R of the circumferential inner circumferential surface E different from each other. In addition, in the present embodiment, the radial pocket short diameter a of the radial inner circumferential surface D is made to coincide with the radial pocket short diameter a of the circumferential inner circumferential surface E, but they may be made different from each other. In addition, in the present embodiment, the axial pocket major diameter c of the radial inner circumferential surface D and the circumferential pocket major diameter b of the circumferential inner circumferential surface E are made to coincide with each other, but they may be made different from each other.

[0039] Here, the ratio of the radial pocket minor diameter a to the axial pocket major diameter c on the radial inner peripheral surface D is preferably not less than 0.83 and less than 0.97.

[0040] Similarly, the ratio of the radial pocket short diameter a to the circumferential pocket long diameter b on the circumferential inner peripheral surface E is preferably not less than 0.83 and less than 0.97.

[0041] Since the axial pocket major diameter c and the circumferential pocket major diameter b are larger than the diameter φx of the ball 3, there is a gap between the ball 3 and the retainer 20 to generate a circumferential gap (see Figure 5 The circumferential direction is the direction of the ball 3's rotation, so the lubricating oil can be introduced from the gap into the oil reservoir and discharged from the oil reservoir. That is, the lubricating oil can be temporarily retained in the oil reservoir to prevent oil shortage, and the increase of stirring resistance caused by excessive accumulation of lubricating oil and the heat generated thereby can be prevented. Therefore, the circumferential direction needs to be the long side of the ellipse.

[0042] In addition, if Figure 4 As shown in FIG. 1 , the inner circumferential surface of the pocket 23 in the cross section perpendicular to the radial straight line of the bearing passing through the pocket center p (referred to as the inner circumferential surface in the plane direction) is formed by a perfect circle having the circumferential pocket major diameter b as its diameter. However, the inner circumferential surface in the plane direction is not limited to a perfect circle. For example, the circumferential pocket major diameter b may be set to the major diameter of an ellipse ( Figure 4 ) and in the direction orthogonal to it ( Figure 4 The inner circumferential surface in the plane direction extends from the front end G of the retaining claw 22a through the bottom F of the pocket 23 to the front end G of the retaining claw 22a on the opposite side.

[0043] In addition, Figure 3 , it is shown that the radial inner peripheral surface D continues from the outer diameter side end d2 to the inner diameter side end d1 at the bottom F of the pocket 23 . Figure 3 The radial inner circumferential surface D of a cross section passing through the center line of the bearing is shown, but the radial inner circumferential surface D is set not only in this cross section, but also in any cross section including a straight line in the radial direction of the bearing connecting the pocket center p and the axis of the bearing. However, when a recessed portion H such as an oil reservoir is provided in the pocket 23, the location of the recessed portion H is excluded.

[0044] In addition, similarly Figure 4 The circumferential inner surface E of a cross section passing through the center p of the pocket and being orthogonal to the radial straight line of the bearing connecting the center p of the pocket and the axis of the bearing is shown, but the circumferential inner surface E is set not only in this cross section, but also in any cross section passing through the center p of the pocket and intersecting the radial straight line of the bearing passing through the center p of the pocket (however, when a recessed portion H such as an oil reservoir is provided in the pocket 23, the location of the recessed portion H is excluded). The radial inner surface D and the circumferential inner surface E are at the bottom F and the side center point J (refer to Figure 5) between any location, for example, the middle location between the bottom F and the side center point J.

[0045] In addition, the radius of the arc of the radial inner peripheral surface D is preferably 0.86 or more and less than 0.98 with respect to 1 / 2 of the diameter φx of the ball 3 in the entire area of ​​the radial inner peripheral surface D. In addition, the radius of the arc of the circumferential inner peripheral surface E is preferably 0.86 or more and less than 0.98 with respect to 1 / 2 of the diameter φx of the ball 3 in the entire area of ​​the circumferential inner peripheral surface E. Thus, a gap that can serve as an oil reservoir can be ensured between the ball 3 and the bottom F of the pocket 23.

[0046] In addition, assuming that a portion with a radius of less than 0.86 relative to 1 / 2 of the diameter φx of the ball 3 is sandwiched in the circular arc of the radial inner circumferential surface D, the front angle between the ball 3 and the retainer 20, that is, the acute angle formed by the tangent direction of the circular arc of the radial inner circumferential surface D at the inner diameter side end d1 and the outer diameter side end d2 and the tangent direction of the surface of the ball 3 at this position increases. Therefore, the possibility that the lubricating oil is difficult to enter dynamically toward the gap increases. In addition, assuming that the radius of the circular arc of the radial inner circumferential surface D is greater than 0.98 relative to 1 / 2 of the diameter φx of the ball 3, the oil storage portion will not be fully formed between the radial inner circumferential surface D and the ball 3. In addition, if the ratio exceeds 1.00, the oil storage portion will completely disappear. These matters are the same in the circumferential inner circumferential surface E. Therefore, it is preferred to set the above ratio to be greater than 0.86 and less than 0.98.

[0047] However, if Figure 6 As shown in the example of , a retainer 20 may be used in which the outer diameter surfaces of the annular portion 21 and the column portion 22, that is, the retainer outer diameter surface 25, are inclined in the inner diameter direction from the annular portion 21 side toward the protruding end side of the column portion 22. According to this structure, it is possible to prevent the ball 3 deformed by the centrifugal force when the bearing 10 rotates at high speed from coming into strong contact with the retainer 20, thereby preventing the heat caused by the strong contact. In particular, in a retainer 20 having a protruding portion (column portion 22) such as a crown-shaped retainer in a cantilever beam shape, the centrifugal deformation of the protruding portion (column portion 22) during high-speed rotation is large, so such an inclination of the retainer outer diameter surface 25 is effective.

[0048] According to the above structure, for example,

[0049] dmn={(D+d) / 2}×n

[0050] D: Bearing outer diameter (mm)

[0051] d: bearing inner diameter (mm)

[0052] n: Rotation speed (min -1 )

[0053] The bearing 10 used under high-speed conditions in which the maximum rotational speed thereof has a predetermined dmn value of 700,000 or more can be applied to, for example, supporting a motor shaft or a speed reducer shaft that transmits the driving force of a driving motor for an automobile.

[0054] In the above-mentioned embodiment, as the rotating shaft, the rotating shaft of the driving motor provided in the electric transportation equipment such as the electric vehicle or the rotating shaft of the speed reducer or speed increaser provided in the above-mentioned electric transportation equipment is listed, but in addition, the bearing 10 of the present invention and the bearing device using the bearing 10 can also be applied to the support part of the rotating shaft in various transportation equipment, industrial machinery, etc. For example, it can also be applied to the shaft of the power transmission path in various transportation equipment, the rotating part of the constant velocity universal joint, the transmission shaft, the supercharger, the transmission, the wheel bearing, or the support part of the rotating shaft of various machine tools, generators, etc.

[0055] The embodiments disclosed this time should be understood to be illustrative in all aspects and not restrictive. The scope of the present invention is indicated by the claims rather than the above description, and is intended to include all modifications within the meaning and scope equivalent to the claims.

Claims

1. A retainer for a rolling bearing, the rolling bearing comprising an outer ring (1) and an inner ring (2), and a plurality of balls (3) arranged between the outer ring (1) and the inner ring (2), the retainer comprising an annular portion (21) and a plurality of columnar portions (22) protruding from the annular portion (21) in the axial direction of the bearing, and comprising pockets (23) for retaining the balls (3), the pockets (23) being formed between the columnar portions (22, 22) adjacent to each other in the circumferential direction of the bearing, The retainer is characterized in that The radius of the arc of the radial inner surface (D) of the pocket (23) in a cross section passing through the pocket center (p) of the pocket (23) and including the bearing center line (o) is set to be smaller than 1 / 2 of the diameter φx of the ball (3) over the entire area of ​​the radial inner surface (D).

2. The retainer according to claim 1, characterized in that The radial inner peripheral surface (D) coincides with an imaginary line (R) formed by an ellipse having a radial pocket short diameter (a) smaller than the diameter φx of the ball (3) in the radial direction of the bearing and an axial pocket long diameter (c) larger than the diameter φx of the ball (3) in the axial direction of the bearing.

3. The retainer according to claim 1 or 2, characterized in that: The radius of the arc of the circumferential inner surface (E) of the pocket (23) in a cross section passing through the center of the pocket (p) and orthogonal to the bearing center line (o) is set to be smaller than 1 / 2 of the diameter φx of the ball (3) over the entire area of ​​the circumferential inner surface (E).

4. The retainer according to claim 3, characterized in that: The circumferential inner surface (E) coincides with an imaginary line (R) formed by an ellipse having a radial pocket short diameter (a) smaller than the diameter φx of the ball (3) in the radial direction of the bearing and a circumferential pocket long diameter (b) larger than the diameter φx of the ball (3) in the tangential direction relative to the circumference of the bearing.

5. The retainer according to claim 2, characterized in that: The ratio of the radial pocket short diameter (a) to the axial pocket long diameter (c) is greater than or equal to 0.83 and less than 0.

97.

6. The retainer according to claim 4, characterized in that: The ratio of the radial pocket short diameter (a) to the circumferential pocket long diameter (b) is greater than or equal to 0.83 and less than 0.

97.

7. The retainer according to claim 1, characterized in that: The radial inner peripheral surface (D) coincides with an imaginary line (R) formed by an ellipse having a radial pocket minor diameter (a) smaller than the diameter φx of the ball (3) in the radial direction of the bearing and an axial pocket major diameter (c) larger than the diameter φx of the ball (3) in the axial direction of the bearing, The circumferential inner surface (E) of the pocket (23) in a cross section passing through the pocket center (p) and orthogonal to the bearing center line (o) coincides with an imaginary line (R) formed by an ellipse having a radial pocket short diameter (a) smaller than the diameter φx of the ball (3) in the radial direction of the bearing and a circumferential pocket long diameter (b) larger than the diameter φx of the ball (3) in the tangential direction relative to the circumference of the bearing, The centers of the ellipse of the imaginary line (R) of the radial inner peripheral surface (D) and the ellipse of the imaginary line (R) of the circumferential inner peripheral surface (E) coincide with each other.

8. The retainer according to any one of claims 1 to 7, characterized in that: The radius of the circular arc of the radial inner peripheral surface (D) is not less than 0.86 and less than 0.98 with respect to 1 / 2 of the diameter φx of the ball (3) in the entire area of ​​the radial inner peripheral surface (D).

9. The retainer according to any one of claims 1 to 8, characterized in that: The retainer outer diameter surfaces (25) of the annular portion (21) and the column portion (22) are inclined in the inner diameter direction from the annular portion (21) side toward the protruding end side of the column portion (22).

10. A bearing device, characterized in that: The rolling bearing using the cage according to any one of claims 1 to 9 is used for supporting a motor shaft or a speed reducer shaft for transmitting the driving force of a driving motor for an automobile.

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