Jade Axle

Abstract

To provide a ball bearing that has a simple configuration but secures oil-feeding property into a guide gap, can suppress progress of wear at a guide surface of a retainer, prevent abnormal behaviors of the retainer and suppress vibration of the bearing.SOLUTION: A ball bearing 10 includes an outer ring 11, an inner ring 12, a plurality of balls 13, and a retainer 20. The retainer 20 includes a plurality of projected and curved grooves 23 each having a groove shape that is projected and curved in a circumferential direction at a guide surface for guiding to the outer ring 11. At least one of the projected and curved grooves 23 has an end that is communicated to pockets 21 of the retainer 20.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a ball bearing, and more particularly to a ball bearing that includes an outer ring guide type cage and is capable of suppressing vibration. [Background technology]

[0002] Conventionally, in ball bearings with a cage using a raceway guide system, friction on the cage's guide surface can cause abnormal cage behavior and vibration in the bearing. For this reason, for example, Patent Document 1 discloses a bearing in which at least one recess, such as a notch, groove, or hole, is provided in the guide surface area axially outside the cage pocket. The interaction between this recess and the lubricant film formed in the guide clearance damps radial vibrations, thereby reducing friction. Patent Document 2 also discloses a bearing in which multiple grease supply holes (through holes) are provided from the inner to outer peripheral surface of the cage, improving the supply of oil to the guide clearance and reducing friction. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] U.S. Patent No. 8,622,622 [Patent Document 2] U.S. Patent No. 9,109,629 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the bearing described in Patent Document 1 is premised on the presence of a lubricant 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 a problem of increased manufacturing costs.

[0005] The present invention has been made in consideration of the above-mentioned problems, and its purpose is to provide a ball bearing that has a simple configuration that ensures oil supply to the guide gap, can suppress the progression of wear on the guide surface of the retainer, prevents abnormal behavior of the retainer, and can suppress bearing vibration. [Means for solving the problem]

[0006] 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. (1) The ball bearing according to the present invention. (3) 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. (1) The ball bearing according to the present invention. (4) 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 the axial direction or in the inclined direction on the guide surface side and that is positioned rearward in the rotational direction as viewed from the radially outer side. The ball bearing according to any one of (1) to (3). [Effects of the Invention]

[0007] According to the ball bearing of the present invention, 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 convexly curved in the circumferential direction, and at least one of the convexly curved grooves has an end that communicates with a pocket, so that grease can be stably stored in the convexly curved grooves, ensuring oil supply to the guide gap with a simple configuration, reducing contact resistance during contact with the outer ring, and suppressing wear on the guide surface. This prevents abnormal behavior of the cage and suppresses bearing vibration. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view of a ball bearing according to an embodiment of the present invention. [Figure 2] FIG. 2 is a perspective view of the cage of FIG. 1. [Figure 3] FIG. 2 is a perspective view of the cage of FIG. 1. [Figure 4] FIG. 10 is a perspective view of a cage according to a first modified example of the present invention. [Figure 5] FIG. 10 is a perspective view of a cage according to a second modified example of the present invention. [Figure 6] FIG. 10 is a perspective view of a cage according to a third modified example of the present invention. [Figure 7] FIG. 10 is a perspective view of a cage according to a fourth modified example of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0009] An angular contact ball bearing according to one embodiment of the present invention will now be described in detail with reference to the drawings. As shown in Figure 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 outer ring raceway groove 11a and inner ring raceway groove 12a with a contact angle α, and a cage 20 having a plurality of pockets 21 that hold balls 13 rollably. Angular contact ball bearing 10 is lubricated with grease as a lubricant. Pockets 21 have a circular shape when viewed radially to match the shape of balls 13.

[0010] The outer ring 11 is formed with a counterbore 11b on one axial side of the outer ring raceway groove 11a, and a shoulder 11c on the other axial side of the outer ring raceway groove 11a.

[0011] The cage 20 is a cylindrical machined cage disposed between the outer ring 11 and the inner ring 12, with a plurality of pockets 21 formed at equal intervals in the circumferential direction at the axially central position. The cage 20 is of an outer ring guide type, where it is guided by sliding contact with the cylindrical inner peripheral surface of the shoulder portion 11c of the outer ring 11.

[0012] The cage 20 is an injection-molded product made of, for example, a material containing synthetic resin. Examples of synthetic resins that can be used for the cage 20 include PPS (polyphenylene sulfide) and PPS-CF (carbon fiber reinforced polyphenylene sulfide). In addition, PA (polyamide), PAI (polyamide imide), thermoplastic polyimide, and PEEK (polyether ether ketone) can be used as the base material, and organic fibers such as carbon fiber, glass fiber, and aramid fiber can be used as the reinforcing fiber.

[0013] 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 a 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 so as 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.

[0014] 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 has moved to the outer peripheral surface of the cage 20 adheres to the guide surfaces 22, and 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 points of the convexly curved grooves 23 formed on one circumferential side, and the grease is stored in these areas. Then, as the amount of 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.

[0015] 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, 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 20, and the expected friction reduction effect between the outer ring 11 and the cage 20 can be achieved.

[0016] The convexly curved groove 23 may be formed by transfer from a mold when molding the cage, or may be formed by cutting the guide surface. The convex 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.

[0017] As explained above, according to the angular contact ball bearing 10 of this embodiment, the cage 20 is provided with a plurality of convexly curved grooves 23, each having a groove shape that is convexly curved in the circumferential direction, on the guide surface 22 that is guided by the outer ring 11, and at least one of the plurality of convexly curved grooves 23 has an end that communicates with the pocket 21, so that grease can be stably stored in the convexly curved groove 23, reducing contact resistance when in 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.

[0018] 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 one 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.

[0019] Therefore, in the cage 20A of this modification, when the cage 20 rotates toward the other circumferential side, the grease moves to the vicinity of the inflection point of the first convex curved groove 23a formed on one circumferential side and is stored in this portion. Also, when the cage 20 rotates toward the one circumferential side, the grease moves to the vicinity of the inflection point of the second convex curved groove 23b formed on the other circumferential side and is stored in this portion.

[0020] This allows grease to be stably stored in the first convex curved groove 23a or the second convex curved groove 23b through the pocket 21 regardless of the direction of rotation, suppressing the progression of wear on the guide surface, thereby preventing abnormal behavior of the retainer and suppressing bearing vibration.

[0021] 5 is a perspective view of a cage according to a second modified example of the present invention. In this cage 20B, the multiple convexly curved grooves 23 have a groove shape, such as a sine wave, 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 correspond to one pocket 21 and are formed on the side of the pocket 21. One axial end of one of the two convexly curved grooves 23 communicates with 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.

[0022] In this case, as in the first variant, depending on the direction of rotation, grease can be stably stored either near the part 23c protruding on one side of the circumference, which is the inflection point, or near the part 23d protruding on the other side of the circumference, thereby suppressing the progression of wear on the guide surface, thereby preventing abnormal behavior of the retainer and suppressing bearing vibration.

[0023] FIG. 6 is a perspective view of a cage according to a third modification of the present invention. In this cage 20C, any pocket is formed in an elliptical shape with a longer axial length than in the cage 20 of FIG. 2. That is, the multiple pockets 21 include a circular pocket 21a and an elliptical pocket 21b with its major axis oriented in the axial direction. A gap is formed in the axial direction between this elliptical pocket 21b and the balls 13, and this gap communicates with the guide gap. In this embodiment, the elliptical pockets 21b are preferably provided at equal intervals in the circumferential direction, and at least two or more pockets are sufficient.

[0024] Since the cage 20C has a 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.

[0025] Fig. 7 is a perspective view of a cage according to a fourth modification of the present invention. In this cage 20D, compared to the cage 20 in Fig. 2, an arbitrary pocket has an oval pocket 21c that is long in the inclined direction and located rearward in the direction of rotation on the guide surface side 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.

[0026] 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 curved 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, achieving the expected friction reduction effect 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.

[0027] 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.

[0028] In addition, in the present invention, the cross-sectional shapes of the circular pockets and the elongated hole-shaped pockets are also arbitrary; for example, the circular pockets may be cylindrical pockets having a cross-sectional linear shape along the radial direction, or may be spherical pockets having a cross-sectional arc shape along the ball.

[0029] Furthermore, in the above embodiment, an angular contact ball bearing is used for explanation, but 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. 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. [Explanation of symbols]

[0030] 10 Angular contact ball bearing (ball bearing) 11 Outer ring 11a Outer ring raceway groove 12 Inner Circle 12a Inner ring raceway groove 13 balls 20 Retainer 21 Pocket 21a Circular pocket 21b, 21c Long hole shaped pocket 22 Guide surface 23 Convex curved groove

Claims

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, 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.

2. 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.

3. 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.

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