JP2024111670A - Ball bearings - Google Patents

Abstract

To provide a ball bearing which can secure the fluidity of grease by a simple constitution, can reduce the friction of a guide face of a cage, is prevented in an abnormal behavior of the cage, and can suppress the vibration of the bearing.SOLUTION: A cage 20 has a first groove 24 extending in an axial direction of the case 20 at a guide face 22 which is guided to an outer ring 11. The first groove 24 has the other side erecting face 24a formed at the other side of the cage 20 in a circumferential direction, and extending up to the guide face 22 along a radial direction, and a one-side inclination face 24b formed at one side of the cage 20 in the circumferential direction, and extending to the outside of the radial direction as progressing toward one side in the circumferential direction.SELECTED DRAWING: Figure 2

Description

The present invention relates to a ball bearing, and more specifically, to a ball bearing equipped with an outer ring guide type retainer and capable of suppressing vibration.

Conventionally, in ball bearings with a cage using a raceway guide system, friction on the cage's guide surface can cause abnormal behavior of the cage, resulting in bearing vibration. For this reason, for example, the bearing described in Patent Document 1 has at least one recess such as a notch, groove, or hole in the guide surface area that is axially outside the cage pocket, and the interaction between this recess and the lubricating film formed in the guide gap damps radial vibrations, thereby reducing friction. In addition, the bearing described in Patent Document 2 has multiple grease oiling holes (through holes) from the inner to outer circumferential surfaces of the cage, improving the oiling ability of the guide gap and reducing friction.

U.S. Pat. No. 8,622,622 U.S. Pat. No. 9,109,629

However, in the bearing described in Patent Document 1, grease may clog the recessed areas under grease lubrication, and the effect of the groove may not be realized, and the desired effect may not be achieved. In addition, in the bearing described in Patent Document 2, the desired effect cannot be achieved unless the diameter of the through hole is an appropriate value. For example, if the diameter of the through hole is too large, there is a possibility that excessive grease may be present on the guide surface or may leak too much to the side, which may actually worsen the lubrication (increase friction). In addition, if the diameter of the through hole is too small, there is a possibility that grease may clog the inside of the through hole, and there is an issue that the desired effect may not be achieved.

The present invention was made in consideration of the above-mentioned problems, and its purpose is to provide a ball bearing that can ensure the fluidity of grease with a simple configuration, reduce friction on the guide surface of the retainer, prevent abnormal behavior of the retainer, and suppress bearing vibration.

The above object of the present invention can be achieved by the following configuration.
[1] An outer ring having an outer ring raceway groove on an inner peripheral surface thereof;
an inner ring having an inner ring raceway groove on an outer peripheral surface;
a plurality of balls rollably disposed between the outer ring raceway groove and the inner ring raceway groove;
a cage having a plurality of pockets for holding the plurality of balls;
A ball bearing comprising:
the cage has at least one recess extending in an axial direction of the cage on a guide surface that is guided by the outer ring,
The ball bearing includes a first recess having, at its bottom, a one-side inclined surface or one-side curved surface formed on one circumferential side of the retainer and extending radially outward as it approaches the one circumferential side, and a second-side upright surface formed on the other circumferential side of the retainer and extending radially from the bottom to the guide surface.

The ball bearing of the present invention has a simple structure that ensures the fluidity of the grease, reduces friction on the guide surface of the retainer, prevents abnormal behavior of the retainer, and suppresses bearing vibration.

1 is a cross-sectional view of a ball bearing according to a first embodiment of the present invention. FIG. 2 is a perspective view of the cage shown in FIG. 1 . 3(a) is a development view of the guide surface of the cage shown in FIG. 2, and FIG. 3(b) is a side view of FIG. 3(a). FIG. 4(a) is a side view showing a first example of the other-side standing surface, and FIG. 4(b) is a side view showing a second example of the other-side standing surface. FIG. 5(a) is a development view of a guide surface of a cage according to a modified example of the first embodiment, and FIG. 5(b) is a side view of FIG. 5(a). FIG. 6(a) is a development view of a guide surface of a cage according to a second embodiment of the present invention, and FIG. 6(b) is a side view of FIG. 6(a). FIG. 7(a) is a development view of a guide surface of a cage according to a first modified example of the second embodiment, and FIG. 7(b) is a side view of FIG. 7(a). FIG. 8(a) is a development view of a guide surface of a cage according to a second modified example of the second embodiment, and FIG. 8(b) is a side view of FIG. 8(a). FIG. 11 is a perspective view of a cage according to a modified example of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a ball bearing according to the present invention will be described in detail with reference to the drawings.
First Embodiment
1, an angular ball bearing (ball bearing) 10 includes an outer ring 11 having an outer ring raceway groove 11a on its inner peripheral surface, an inner ring 12 having an inner ring raceway groove 12a on its outer peripheral surface, a plurality of balls (rolling elements) 13 rollably arranged with a contact angle α between the outer ring raceway groove 11a and the inner ring raceway groove 12a, and a cage 20 having a plurality of pockets 21 that hold the balls 13 rollably. The angular ball bearing 10 is lubricated with grease as a lubricant. The pockets 21 have a circular shape when viewed from the radial direction to match the shape of the balls 13.

The outer ring 11 has a counterbore 11b formed on one axial side of the outer ring raceway groove 11a, and a shoulder 11c formed on the other axial side of the outer ring raceway groove 11a.

The cage 20 is a cylindrical machined cage that is disposed between the outer ring 11 and the inner ring 12 and has multiple pockets 21 formed at equal intervals in the circumferential direction at the axially central position. The cage 20 is of the outer ring guide type, where it is guided by sliding against the cylindrical inner peripheral surface of the shoulder 11c of the outer ring 11.

The retainer 20 is, for example, an injection molded product using a material containing synthetic resin. Examples of synthetic resins that can be used for the retainer 20 include PPS (polyphenylene sulfide) and PPS-CF (carbon fiber reinforced polyphenylene sulfide). Other examples of base materials that can be used include PA (polyamide), PAI (polyamideimide), thermoplastic polyimide, and PEEK (polyether ether ketone), and examples of reinforcing fibers that can be used include organic fibers such as carbon fiber, glass fiber, and aramid fiber.

As shown in Figures 2 and 3, a plurality of first grooves (first recesses) 24 and second grooves (second recesses) 23 are formed alternately in the circumferential direction on the guide surface 22, which is the outer peripheral surface of the retainer 20 that is guided by the inner peripheral surface of the outer ring 11. The first grooves 24 and the second grooves 23 are grooves formed on the guide surface 22 of the retainer 20 and extend in the axial direction. The axial shapes of the first grooves 24 and the second grooves 23 are not particularly limited, but if they are linear grooves extending in the axial direction of the retainer 20, they can be easily processed and the manufacturing costs can be reduced.

The first groove 24 and the second groove 23 may be formed over the entire axial width of the retainer 20, or may be formed in a portion of the axial width of the retainer 20. Furthermore, the phase (circumferential spacing) of the multiple first grooves 24 and second grooves 23 is not particularly limited, and can be formed in any phase. In other words, the phase of the first grooves 24 and second grooves 23 and the pocket 21 is not limited. In this embodiment, the first groove 24 or the second groove 23 passes through the circumferential middle position of the pocket 21, and the first groove 24 and the second groove 23 are formed between adjacent pockets 21.

The first groove 24 has a second side rising surface 24a formed on the other circumferential side of the retainer 20, a first side inclined surface 24b formed on one circumferential side of the retainer 20, i.e., opposite the second side rising surface 24a, and a bottom surface 24c connecting the second side rising surface 24a and the first side inclined surface 24b. The second side rising surface 24a is a vertical wall portion formed along the radial direction from the bottom surface 24c of the first groove 24 to the guide surface 22 of the retainer 20, and the first side inclined surface 24b is an inclined surface extending radially outward from the bottom surface 24c toward the first circumferential side to the guide surface 22. The bottom surface 24c is a flat or curved surface along the circumferential direction of the retainer 20.

That is, the first groove 24 in this embodiment has, at its bottom, a bottom surface 24c and a one-side inclined surface 24b formed on one circumferential side of the retainer 20 and extending radially outward as it approaches that one circumferential side, and has an other-side upright surface 24a formed on the other circumferential side of the retainer 20 and extending radially from the bottom to the guide surface 22.
The one-side inclined surface 24b is inclined so as to extend radially outward from the bottom to the guide surface 22 as it approaches one circumferential side.

The other side upright surface 24a may be a surface along a plane extending radially through the axial center O, as shown in FIG. 4(a), or may be a surface parallel to a plane passing through the circumferential middle position of the first groove 24 and the axial center O, as shown in FIG. 4(b).

The second groove 23 has a one-side rising surface 23a formed on one circumferential side of the retainer 20, a other-side inclined surface 23b formed on the other circumferential side of the retainer 20, i.e., opposite the one-side rising surface 23a, and a bottom surface 23c connecting the one-side rising surface 23a and the other-side inclined surface 23b. The one-side rising surface 23a is a standing wall portion formed along the radial direction from the bottom surface 23c of the second groove 23 to the guide surface 22 of the retainer 20, and the other-side inclined surface 23b is an inclined surface extending radially outward from the bottom surface 23c toward the other circumferential side to the guide surface 22. The bottom surface 23c is a flat or curved surface along the circumferential direction of the retainer 20.

That is, the second groove 23 in this embodiment has, at its bottom, a bottom surface 23c and an other-side inclined surface 23b formed on the other circumferential side of the retainer 20 and extending radially outward as it approaches the other circumferential side, and also has a one-side upright surface 24a formed on one circumferential side of the retainer 20 and extending radially from the bottom to the guide surface 22.
The other-side inclined surface 23b is inclined so as to extend radially outward from the bottom to the guide surface 22 as it approaches the other circumferential side.

The one-side upright surface 23a, like the other-side upright surface 24a, may be a surface along a plane passing through the axial center O, or may be a surface parallel to a plane passing through the circumferential middle position of the second groove 23 and the axial center O.

During operation of a bearing 10 equipped with such a retainer 20, the grease present on the inner peripheral surface of the retainer 20 is supplied from the inner peripheral surface of the retainer 20 to the outer peripheral surface through the gap between the pocket 21 and the balls 13 by the centrifugal force accompanying the rotation of the bearing 10. A portion of the grease that has moved to the outer peripheral surface of the retainer 20 adheres to the guide surface 22, and the remainder is stored in the first groove 24 and the second groove 23.

For example, when the retainer 20 rotates toward the other circumferential side (retainer 20 moves downward in FIG. 3), the grease on the guide surface 22 is sheared between the inner peripheral surface of the outer ring 11 and the guide surface 22, and this shear force guides the grease from the guide surface 22 to the first groove 24. The grease film thickness on the guide surface 22 is smaller than that of the first groove 24, and when the grease moves from the guide surface 22 to the first groove 24, the grease film thickness increases rapidly, coupled with the action of the other side upright surface 24a. This generates negative pressure in that area due to a reverse wedge effect. This negative pressure acts to further draw the grease into the first groove 24.

The grease stored in the first groove 24 is sheared between the inner peripheral surface of the outer ring 11 and the guide surface 22, and this shear force guides the grease from the first groove 24 to the guide surface 22 via the one-side inclined surface 24b. The inclination of the one-side inclined surface 24b ensures the fluidity of the grease from the first groove 24 to the guide surface 22, reducing the contact resistance when it comes into contact with the outer ring 11, and achieving a friction reduction effect.

On the other hand, when the retainer 20 rotates toward one side in the circumferential direction (the retainer 20 moves upward in FIG. 3), the grease on the guide surface 22 is guided to the second groove 23 by the shear force between the inner peripheral surface of the outer ring 11 and the guide surface 22. The grease film thickness on the guide surface 22 is smaller than that of the second groove 23, and when the grease moves from the guide surface 22 to the second groove 23, the grease film thickness increases rapidly, coupled with the action of the upright surface 23a on one side. This generates negative pressure in that area due to a reverse wedge effect. This negative pressure acts to draw the grease further into the second groove 23.

The grease stored in the second groove 23 is sheared between the inner peripheral surface of the outer ring 11 and the guide surface 22, and this shear force guides the grease from the second groove 23 to the guide surface 22 via the other side inclined surface 23b. The inclination of the other side inclined surface 23b ensures the fluidity of the grease from the second groove 23 to the guide surface 22, reducing the contact resistance when it comes into contact with the outer ring 11, and achieving a friction reduction effect.

In this way, by arranging the first grooves 24 and the second grooves 23 alternately in the circumferential direction, the fluidity of the grease can be ensured and the grease can be supplied between the inner peripheral surface of the outer ring 11 and the guide surface 22 regardless of the rotational direction of the cage 20, reducing contact resistance and friction. In addition, the dimensions of the first groove 24 and the second groove 23 can be appropriately set depending on the inclination and length of the one-side inclined surface 24b and the other-side inclined surface 23b and the length of the bottom surfaces 24c and 23c.

When the retainer 20 is used with a rotation direction limited to one direction, only one of the first groove 24 and the second groove 23 may be provided to match that rotation direction.

The first groove 24 and the second groove 23 may be formed by transfer from a mold when molding the cage, or may be formed by cutting the guide surface 22. Furthermore, it is preferable that the first groove 24 and the second groove 23 are designed to have a size that provides damping against radial vibrations by interaction with a lubricating film formed in the guide gap (the gap between the inner peripheral surface of the outer ring 11 and the guide surface 22).

As described above, according to the angular ball bearing 10 of this embodiment, the retainer 20 has a guide surface 22 guided by the outer ring 11, in which the first groove 24 having the other side upright surface 24a and one side inclined surface 24b and the second groove 23 having the one side upright surface 23a and the other side inclined surface 23b are alternately formed in the circumferential direction. Therefore, regardless of the rotation direction of the retainer 20, grease can be stably stored in the first groove 24 and the second groove 23 and supplied to the guide surface 22, reducing the contact resistance when contacting the outer ring 11 and reducing the friction of the guide surface 22. This prevents abnormal behavior of the retainer 20 and suppresses vibration of the bearing 10.

(Modification of the first embodiment)
Next, a cage according to a modification of the first embodiment will be described with reference to FIG.
In the cage 20 of this modified example, the first groove 24 and the second groove 23 are formed with a one-side curved surface 24d and an other-side curved surface 23d that extend radially outward toward one circumferential side and the other circumferential side, respectively, instead of the one-side inclined surface 24b and the other-side inclined surface 23b. The other-side upright surface 24a and the one-side curved surface 24d, and the one-side upright surface 23a and the other-side curved surface 23d are formed continuously without having a bottom surface therebetween.
The cage 20 of this modified example can also achieve the same effects as the cage of the first embodiment.

Second Embodiment
Next, a cage according to a second embodiment will be described with reference to FIG.
The cage 20 of this embodiment has one type of groove (first groove, first recess) 25 whose cross-sectional shape is symmetrical in the circumferential direction.

The groove 25 has, on the other circumferential side of the retainer 20, a other-side rising surface 24a formed along the radial direction up to the guide surface 22 of the retainer 20, and a other-side inclined surface 23b extending radially outward as it approaches the other circumferential side, and, on one circumferential side of the retainer 20, a one-side rising surface 23a formed along the radial direction up to the guide surface 22 of the retainer 20, and a one-side inclined surface 24b extending radially outward as it approaches the one circumferential side.

That is, groove 25 is a groove formed in an approximately V-shape with an opening that opens on the guide surface 22 side, and, from the top of Figure 6, one side standing surface 23a, one side inclined surface 24b, other side inclined surface 23b, and other side standing surface 24a are formed in succession.
Therefore, the groove 25 has, at its bottom, a one-side inclined surface 24b and an other-side inclined surface 23b, and, on one circumferential side and the other circumferential side of the retainer 20, a one-side upright surface 23a and an other-side upright surface 24a extending radially from the bottom to the guide surface 22.

When the cage 20 rotates toward the other circumferential side (the cage 20 moves downward in FIG. 6), the grease on the guide surface 22 is sheared between the inner peripheral surface of the outer ring 11 and the guide surface 22, and this shear force guides the grease from the guide surface 22 to the groove 25. The grease film thickness on the guide surface 22 is smaller than that of the groove 25, and when the grease moves from the guide surface 22 to the groove 25, the grease film thickness increases rapidly, coupled with the action of the other side upright surface 24a. This generates negative pressure in that area due to a reverse wedge effect. This negative pressure acts to draw the grease further into the groove 25.

The grease stored in the groove 25 is sheared between the inner peripheral surface of the outer ring 11 and the guide surface 22, and this shear force guides the grease from the groove 25 to the guide surface 22 via the one-side inclined surface 24b. The inclination of the one-side inclined surface 24b ensures the fluidity of the grease from the groove 25 to the guide surface 22. In other words, when the retainer 20 rotates to the other circumferential side, the other-side upright surface 24a and the one-side inclined surface 24b cooperate to supply grease to the guide surface 22, as with the retainer 20 of the first embodiment, reducing the contact resistance when contacting the outer ring 11 and achieving a friction reduction effect.

Similarly, when the retainer 20 rotates toward one side in the circumferential direction (the retainer 20 moves upward in FIG. 6), the grease on the guide surface 22 is sheared between the inner peripheral surface of the outer ring 11 and the guide surface 22, and this shear force guides the grease from the guide surface 22 to the groove 25. The grease film thickness on the guide surface 22 is smaller than that of the groove 25, and when the grease moves from the guide surface 22 to the groove 25, the grease film thickness increases rapidly, coupled with the action of the upright surface 23a on one side. This generates negative pressure in that area due to a reverse wedge effect. This negative pressure acts to draw the grease further into the groove 25.

The grease stored in the groove 25 is sheared between the inner peripheral surface of the outer ring 11 and the guide surface 22, and this shear force guides the grease from the groove 25 to the guide surface 22 via the other side inclined surface 23b. The inclination of the other side inclined surface 23b ensures the fluidity of the grease from the groove 25 to the guide surface 22. In other words, when the retainer 20 rotates to the other circumferential side, the one side standing surface 23a and the other side inclined surface 23b cooperate to supply grease to the guide surface 22, as with the retainer 20 of the first embodiment, and the contact resistance at the time of contact with the outer ring 11 is reduced, thereby achieving a friction reduction effect.

According to the retainer 20 of this embodiment, the groove 25 allows grease to be supplied to the guide surface 22 regardless of the rotation direction of the retainer 20.

(First Modification of the Second Embodiment)
As shown in Fig. 7, the cage 20 of this modified example is an example in which the other-side inclined surface 23b and the one-side inclined surface 24b of the cage 20 of the second embodiment described in Fig. 6 are connected by a bottom surface 23c. By having the bottom surface 23c, the cage 20 of this modified example can be easily processed.
In addition, the cage 20 of this modified example can achieve the same effects as the cage of the second embodiment.

(Second Modification of the Second Embodiment)
As shown in Figure 8, in the retainer 20 of this modified example, instead of the one-side inclined surface 24b and the other-side inclined surface 23b of the groove 25 described in Figure 6, a one-side curved surface 24d and an other-side curved surface 23d are formed which extend radially outward as they approach the other circumferential side and the one circumferential side, and which are concavely curved.
That is, groove 25 is a groove formed in an approximately U-shape with an opening that opens on the guide surface 22 side, and from the top of Figure 8, one side standing surface 23a, one side curved surface 24d, the other side curved surface 23d, and the other side standing surface 24a are formed continuously.
The cage 20 of this modified example can also achieve the same effects as the cage of the second embodiment.

The present invention is not limited to the above-described embodiment, and can be modified, improved, etc. as appropriate.
For example, while the above embodiment has been described using an angular contact ball bearing, the present invention is not limited to this and can also be applied to ball bearings of other configurations, such as self-aligning ball bearings and four-point contact ball bearings.
In addition, for example, in the case of a retainer having guide surfaces on both axial sides, or in a bearing where strict balance of the retainer with respect to the rotating shaft is required, the above-mentioned groove may be provided on the guide surfaces on both axial sides.
In addition, the type of cage is a cylindrical machined cage in the above embodiment, but is not limited to this and may be another cage shape.
Furthermore, the first groove 24, the second groove 23, and the groove 25 of this embodiment may be a first recess, a second recess, and a recess that are rectangular and have closed axial ends.

The groove (recess) of the present invention is not limited to that of the above embodiment, and may be, for example, a groove 26 formed at an incline with respect to the axial direction so as to connect between the axial end of the cage and the pocket, as shown in FIG. 9. In this case, the groove 26 is bent at its axial middle portion so as to protrude most to one circumferential side or the other circumferential side. Also, in this case, the shape of the groove 26 may be configured with two types of shapes, the first groove 24 and the second groove 23, as in the first embodiment, or may be configured with one type of shape, the groove 25, as in the second embodiment.

As described above, the present specification discloses the following:
(1) an outer ring having an outer ring raceway groove on an inner peripheral surface;
an inner ring having an inner ring raceway groove on an outer peripheral surface;
a plurality of balls rollably disposed between the outer ring raceway groove and the inner ring raceway groove;
a cage having a plurality of pockets for holding the plurality of balls;
A ball bearing comprising:
the cage has at least one recess extending in an axial direction of the cage on a guide surface that is guided by the outer ring,
The ball bearing includes a first recess having, at its bottom, a one-side inclined surface or one-side curved surface formed on one circumferential side of the retainer and extending radially outward as it approaches the one circumferential side, and a second-side upright surface formed on the other circumferential side of the retainer and extending radially from the bottom to the guide surface.
According to this configuration, the fluidity of the grease can be ensured with a simple structure, friction on the guide surface of the retainer can be reduced, abnormal behavior of the retainer can be prevented, and vibration of the bearing can be suppressed.

(2) The ball bearing according to (1), wherein the one-side inclined surface or the one-side curved surface is inclined or curved so as to extend radially outward to the guide surface as it moves from the bottom portion toward the one circumferential side.
According to this configuration, the fluidity of the grease is improved, and the grease stored in the recess can be efficiently supplied to the guide surface.

(3) The ball bearing according to (1), further comprising a flat or curved bottom surface along a circumferential direction between the other-side upright surface and the one-side inclined surface or the one-side curved surface.
This configuration makes it easier to process the recesses.

(4) The ball bearing according to (1), in which the other-side upright surface and the one-side inclined surface or the one-side curved surface are continuous with each other.
According to this configuration, the fluidity of the grease is improved, and the grease stored in the recess can be efficiently supplied to the guide surface.

(5) The ball bearing described in (1), wherein the recess has, at its bottom, a second recess formed on the other circumferential side of the retainer and having a one-side inclined surface or other-side curved surface that extends radially outward as it approaches the other circumferential side, and a second recess is formed on one circumferential side of the retainer and has a one-side upright surface that extends radially from the bottom to the guide surface.
According to this configuration, the grease stored in the recess can be efficiently supplied to the guide surface regardless of the rotation direction of the cage.

(6) The one-side inclined surface or the one-side curved surface is inclined or curved so as to extend radially outward from the bottom portion to the guide surface as it approaches the one circumferential side,
The ball bearing according to (5), wherein the other-side inclined surface or the other-side curved surface is inclined or curved so as to extend radially outward from the bottom to the guide surface as it approaches the other circumferential side.
According to this configuration, the grease stored in the recess can be efficiently supplied to the guide surface regardless of the rotation direction of the cage.

(7) The first recess has, at a bottom portion thereof, a second-side inclined surface or a second-side curved surface that is formed on the other circumferential side of the cage and extends radially outward as it approaches the other circumferential side, and has a first-side upright surface that is formed on one circumferential side of the cage and extends radially from the bottom portion to the guide surface,
The other side upright surface and the other side inclined surface or the other side curved surface are formed continuously,
The ball bearing according to (1), wherein the one-side upright surface and the one-side inclined surface or the one-side curved surface are formed continuously.
According to this configuration, the grease stored in the recess can be efficiently supplied to the guide surface regardless of the rotation direction of the cage. Also, machining of the recess becomes easier.

10 Angular ball bearing (ball bearing)
11 Outer ring 11a Outer ring raceway groove 12 Inner ring 12a Inner ring raceway groove 13 Ball 20 Cage 21 Pocket 22 Guide surface 23 Second groove (second recess)
23a: one side upright surface 23b: other side inclined surface 23c, 24c: bottom surface 23d: other side curved surface 24: first groove (first recess)
24a Other side upright surface 24b One side inclined surface 24d One side curved surface 25 Groove (recess)

Claims (7)

an outer ring having an outer ring raceway groove on an inner peripheral surface;
an inner ring having an inner ring raceway groove on an outer peripheral surface;
a plurality of balls rollably disposed between the outer ring raceway groove and the inner ring raceway groove;
a cage having a plurality of pockets for holding the plurality of balls;
A ball bearing comprising:
the cage has at least one recess extending in an axial direction of the cage on a guide surface that is guided by the outer ring,
The ball bearing includes a first recess having, at its bottom, a one-side inclined surface or one-side curved surface formed on one circumferential side of the retainer and extending radially outward as it approaches the one circumferential side, and a second-side upright surface formed on the other circumferential side of the retainer and extending radially from the bottom to the guide surface. The ball bearing according to claim 1, wherein the one-side inclined surface or the one-side curved surface is inclined or curved so as to extend radially outward from the bottom to the guide surface as it approaches the one circumferential side. The ball bearing according to claim 1, which has a flat or curved bottom surface along the circumferential direction between the other side upright surface and the one side inclined surface or the one side curved surface. The ball bearing according to claim 1, wherein the other side upright surface and the one side inclined surface or the one side curved surface are continuous. The ball bearing according to claim 1, wherein the recess has, at its bottom, a second recess formed on the other circumferential side of the retainer and having a second side inclined surface or a second side curved surface that extends radially outward toward the other circumferential side, and a second recess formed on one circumferential side of the retainer and having a first side upright surface that extends radially from the bottom to the guide surface. the one-side inclined surface or the one-side curved surface is inclined or curved so as to extend radially outward from the bottom portion to the guide surface as it moves toward the one circumferential side,
The ball bearing according to claim 5 , wherein the other-side inclined surface or the other-side curved surface is inclined or curved so as to extend radially outward from the bottom portion to the guide surface as it approaches the other circumferential side. the first recess has, at its bottom, a second-side inclined surface or a second-side curved surface that is formed on the other circumferential side of the cage and extends radially outward as it approaches the other circumferential side, and has a first-side upright surface that is formed on one circumferential side of the cage and extends radially from the bottom to the guide surface,
The other side upright surface and the other side inclined surface or the other side curved surface are formed continuously,
The ball bearing according to claim 1 , wherein the one-side upright surface and the one-side inclined surface or the one-side curved surface are formed continuously.

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