JP7806546B2 - ball bearing - Google Patents

Description

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

Conventionally, in ball bearings with a cage that uses a raceway guide system, friction on the cage's guide surface can cause abnormal cage behavior, 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 axially outside the cage pocket. The interaction between this recess and the lubricant film formed in the guide gap damps radial vibrations, thereby reducing friction. Also, Patent Document 2 describes a bearing with multiple grease supply holes (through holes) from the inner to outer peripheral surface of the cage, improving the supply of oil to the guide gap and reducing friction.

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

However, the bearing described in Patent Document 1 is based on the premise that lubricant is present in the guide gap, and it is desirable to improve the oil supply to the guide gap. The bearing described in Patent Document 2 aims to improve the oil supply to the guide gap by providing a through hole, but this poses the problem of increased manufacturing costs.

The present invention was made in consideration of the above-mentioned problems, and its purpose is to provide a ball bearing that ensures oil supply to the guide gap with a simple configuration, suppresses wear on the guide surface of the cage, prevents abnormal behavior of the cage, and suppresses 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 its inner peripheral surface;
an inner ring having an inner ring raceway groove on its 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 a guide surface that is guided by the outer ring, and the guide surface has a plurality of convexly curved grooves that are curved convexly in the circumferential direction,
At least one of the plurality of convexly curved grooves has an end communicating with the pocket.
ball bearings.
(2) The plurality of convexly curved grooves include a first convexly curved groove having a groove shape that is convexly curved on one circumferential side and a second convexly curved groove having a groove shape that is convexly curved on the other circumferential side,
The first convexly curved groove and the second convexly curved groove have groove shapes that are symmetrical to each other in the circumferential direction and are arranged alternately in the circumferential direction.
A ball bearing according to (1).
(3) The plurality of convexly curved grooves have a groove shape in which a portion convexly curved toward one circumferential side and a portion convexly curved toward the other circumferential side are connected in the axial direction.
A ball bearing according to (1).
(4) The plurality of pockets include a pocket having a circular shape when viewed from the radially outer side, and a pocket having an oblong hole shape that is long in the axial direction or in the inclined direction on the guide surface side and that is located rearward in the rotation direction when viewed from the radially outer side.
A ball bearing according to any one of (1) to (3).

In the ball bearing of the present invention, the cage has a guide surface that is guided by the outer ring, and is provided with multiple convexly curved grooves that are convexly curved in the circumferential direction. At least one of the multiple convexly curved grooves has an end that connects to a pocket, allowing grease to be stably stored in the multiple convexly curved grooves. This simple configuration ensures oil supply to the guide gap, reduces contact resistance during contact with the outer ring, and suppresses the progression of wear on the guide surface. This prevents abnormal behavior of the cage and suppresses bearing vibration.

1 is a cross-sectional view of a ball bearing according to an embodiment of the present invention. FIG. 2 is a perspective view of the cage of FIG. 1; FIG. 2 is a perspective view of the cage of FIG. 1; FIG. 10 is a perspective view of a cage according to a first modified example of the present invention. FIG. 10 is a perspective view of a cage according to a second modified example of the present invention. FIG. 10 is a perspective view of a cage according to a third modified example of the present invention. FIG. 10 is a perspective view of a cage according to a fourth modified example of the present invention.

An angular contact ball bearing according to one embodiment of the present invention will now be described in detail with reference to the drawings.
1, angular contact 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 between the outer ring raceway groove 11a and the inner ring raceway groove 12a with a contact angle α, and a cage 20 having a plurality of pockets 21 that rollably hold the balls 13. Angular contact ball bearing 10 is lubricated with grease as a lubricant. The pockets 21 have a circular shape when viewed radially 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 positioned between the outer ring 11 and the inner ring 12, with multiple pockets 21 formed at equal intervals circumferentially at the axially central position. The cage 20 is an outer ring guide type, guided by sliding contact with the cylindrical inner peripheral surface of the shoulder 11c of the outer ring 11.

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

2 and 3, a plurality of convexly curved grooves 23 having a groove shape that is convexly curved on one circumferential side is formed on the guide surface 22 of the cage 20, which is guided by the inner circumferential surface of the shoulder portion 11c of the outer ring 11. In this embodiment, two convexly curved grooves 23 correspond to one pocket 21 and are formed on the side of the pocket 21, and one axial end of one of the two convexly curved grooves 23 communicates with the pocket 21. In addition, the other axial end of each of the plurality of convexly curved grooves 23 is formed to open at the axial end face of the cage 20. Grease accumulates in these convexly curved grooves 23, reducing contact resistance during contact with the outer ring 11 and suppressing the progression of wear.
The groove shape of the convexly curved groove 23 may be any of a parabolic shape, a U-shape, a semicircular shape, and a sine wave shape.

As a result, during operation, the grease present on the inner peripheral surface of the cage 20 is supplied from the inner peripheral surface to the outer peripheral surface of the cage 20 through the gap between the pockets 21 and the balls 13 due to the centrifugal force generated by the rotation of the bearing. Some of the grease that migrates to the outer peripheral surface of the cage 20 adheres to the guide surfaces 22, while the remainder is stored in the convexly curved grooves 23. In particular, as the cage 20 rotates toward the other circumferential side, the grease moves near the inflection point of the convexly curved grooves 23 formed on one circumferential side, and the grease is stored in this area. Then, as the grease on the guide surfaces 22 decreases, the surface tension effect of the grease on the reduced guide surfaces 22 of the cage 20 and the centrifugal force of the cage 20 cause the grease stored in the convexly curved grooves 23 to be appropriately supplied to the guide surfaces 22 of the cage 20.

Furthermore, if the amount of grease accumulated exceeds the capacity of the convexly curved groove 23, the grease is discharged from the axial end of the convexly curved groove 23 of the cage 20, ensuring the fluidity of the grease. This allows an appropriate amount of grease to be present in the guide gap between the inner surface of the shoulder portion 11c of the outer ring 11 and the guide surface 22 of the cage 20, achieving the expected friction reduction effect between the outer ring 11 and the cage 20.

The convex curved groove 23 may be formed by transferring from a mold when molding the cage, or may be formed by cutting the guide surface.
The convex curved groove 23 is designed to have a size that provides damping against vibrations in the radial direction through interaction with the lubricating film formed in the guide gap.

As described above, according to the angular contact ball bearing 10 of this embodiment, the cage 20 has a plurality of convexly curved grooves 23 on the guide surface 22 that is guided by the outer ring 11, each of which has a groove shape that is convexly curved in the circumferential direction. At least one of the plurality of convexly curved grooves 23 has an end that communicates with the pocket 21, allowing grease to be stably stored in the convexly curved groove 23, reducing contact resistance during contact with the outer ring 13 and suppressing the progression of wear on the guide surface. This prevents abnormal behavior of the cage 20 and suppresses vibration of the bearing 10.

4 is a perspective view of a cage according to a first modified example of the present invention. In this cage 20A, a first convexly curved groove 23a having a groove shape that is convexly curved on one circumferential side and a second convexly curved groove 23b having a groove shape that is convexly curved on the other circumferential side are formed in the guide surface 22 for each pocket 21. Furthermore, one axial end of each of the first convexly curved groove 23a and the second convexly curved groove 23b communicates with the pocket 21, and the other axial end opens to the axial end face of the cage 20.
The groove shape of the convexly curved grooves 23a and 23b may be any of a parabolic shape, a U-shape, a semicircular shape, and a sine wave shape.

Therefore, in this modified retainer 20A, when the retainer 20 rotates toward the other circumferential side, the grease moves near the inflection point of the first convex curved groove 23a formed on one circumferential side, and the grease is stored in this area. Furthermore, when the retainer 20 rotates toward the other circumferential side, the grease moves near the inflection point of the second convex curved groove 23b formed on the other circumferential side, and the grease is stored in this area.

As a result, regardless of the direction of rotation, grease can be stably stored in the first convex groove 23a or the second convex groove 23b via the pocket 21, suppressing the progression of wear on the guide surface. This prevents abnormal behavior of the cage and suppresses bearing vibration.

5 is a perspective view of a cage according to a second modification of the present invention. In this cage 20B, the multiple convexly curved grooves 23 have a sine wave-like groove shape in which a portion 23c convexly curved on one circumferential side and a portion 23d convexly curved on the other circumferential side are connected in the axial direction. Also in this embodiment, two convexly curved grooves 23 are formed on the sides of each pocket 21, and one axial end of one of the two convexly curved grooves 23 is connected to the pocket 21. Furthermore, the other axial end of each of the two convexly curved grooves 23 opens to the axial end face of the cage 20.
The groove shape of the convexly curved groove 23 may be a cubic function shape or an S-shape in addition to a sine wave shape.

In this case, as with the first variant, depending on the direction of rotation, grease can be stably stored near either the inflection point, which is the portion 23c protruding to one side in the circumferential direction, or the portion 23d protruding to the other side in the circumferential direction, thereby suppressing the progression of wear on the guide surface, thereby preventing abnormal behavior of the cage and suppressing bearing vibration.

Figure 6 is a perspective view of a cage according to a third variation of the present invention. In this cage 20C, any pockets are formed in an elliptical shape with a longer axial length than in the cage 20 of Figure 2. That is, the multiple pockets 21 include circular pockets 21a and elliptical pockets 21b with their major axes oriented in the axial direction. A gap is formed in the axial direction between the elliptical pockets 21b and the balls 13, and this gap communicates with the guide gap. In this embodiment, the elliptical pockets 21b are preferably arranged at equal intervals in the circumferential direction, and at least two or more pockets are sufficient.

Since the cage 20C has the circular pocket 21a, misalignment does not occur. Also, the contact points and frequency with the balls 13 in the elliptical pocket 21b are considered to be the same as those in the circular pocket 21a, and uneven wear in the circular pocket 21a can be avoided.
The configuration including the circular pocket 21a and the elliptical pocket 21b can also be combined with the cages 20A and 20B shown in FIGS.

Figure 7 is a perspective view of a cage according to a fourth variation of the present invention. Compared to the cage 20 in Figure 2, this cage 20D has an oval pocket 21c that is long in the inclined direction and located on the guide surface side and rearward in the direction of rotation when viewed from the radial outside. That is, the multiple pockets 21 include a circular pocket 21a and an oval pocket 21c with its major axis facing the inclined direction.

In this case, the ball bearing is limited to rotating in only one direction, but as in the above embodiment, grease can be stably stored in the convex groove 23 via the pockets 21a, 21c, suppressing the progression of wear on the guide surface, thereby preventing abnormal behavior of the retainer and suppressing bearing vibration.
Also in this case, if the amount of grease accumulated exceeds the capacity of the convexly curved groove 23, the grease is discharged from the axial end of the convexly curved groove 23 of the cage 20D, thereby ensuring the fluidity of the grease. This allows an appropriate amount of grease to be present in the guide gap between the inner circumferential surface of the shoulder portion 11c of the outer ring 11 and the guide surface 22 of the cage 20D, and the expected friction reduction effect can be obtained between the outer ring 11 and the cage 20D.
Therefore, like the retainer 20C of the third modified example and the retainer 20D of the fourth modified example, it is preferable that the pocket 21 has a long hole-shaped pocket that is long in the axial direction or in the inclined direction that is rearward in the rotational direction on the guide surface side when viewed from the radial outside.

The present invention is not limited to the above-described embodiment, and modifications and improvements are possible as appropriate.
For example, in the above embodiment, the convexly curved grooves 23 are formed so that two convexly curved grooves correspond to one pocket 21, but the present invention is not limited to this, and the convexly curved grooves may be formed in any phase with respect to the phase of the pocket 21. In addition, the number of convexly curved grooves to be arranged may also be arbitrary.

In addition, in the present invention, the cross-sectional shapes of the circular pockets and slot-shaped pockets are also arbitrary. For example, the circular pockets may be cylindrical pockets with a linear cross-section along the radial direction, or spherical pockets with a cross-section along the arc of the ball.

Furthermore, in the above embodiment, an angular contact ball bearing was used for explanation, but this is not limiting, and the present invention can also be applied to ball bearings of other configurations, such as self-aligning ball bearings and four-point contact ball bearings.
Furthermore, for example, in the case of a retainer having guide surfaces on both axial sides, or in a bearing that requires strict balance of the retainer relative to the rotating shaft, the guide surfaces on both axial sides may have convex curved grooves.
Furthermore, the type of cage is a cylindrical machined cage in the above embodiment, but is not limited to this and may be other cage shapes.

10 Angular contact 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 21a Circular pocket 21b, 21c Slot-shaped pocket 22 Guide surface 23 Convex curved groove

Claims (3)

an outer ring having an outer ring raceway groove on its inner peripheral surface;
an inner ring having an inner ring raceway groove on its 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 a guide surface that is guided by the outer ring, and the guide surface has a plurality of convexly curved grooves that are curved convexly in the circumferential direction,
At least one of the plurality of convexly curved grooves has an end communicating with the pocket,
the plurality of convexly curved grooves include a first convexly curved groove having a groove shape that is convexly curved on one circumferential side, and a second convexly curved groove having a groove shape that is convexly curved on the other circumferential side,
The first convexly curved groove and the second convexly curved groove have groove shapes that are symmetrical to each other in the circumferential direction and are arranged alternately in the circumferential direction.
ball bearings. an outer ring having an outer ring raceway groove on its inner peripheral surface;
an inner ring having an inner ring raceway groove on its 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 a guide surface that is guided by the outer ring, and the guide surface has a plurality of convexly curved grooves that are curved convexly in the circumferential direction,
At least one of the plurality of convexly curved grooves has an end communicating with the pocket,
The plurality of convexly curved grooves have a groove shape in which a portion convexly curved on one circumferential side and a portion convexly curved on the other circumferential side are connected in the axial direction.
ball bearings. The plurality of pockets include a circular pocket as viewed from the radially outer side, and an oblong hole-shaped pocket that is long in an axial direction or an inclined direction on the guide surface side and that is located rearward in the rotational direction as viewed from the radially outer side.
3. A ball bearing according to claim 1 or 2 .