Ball bearing

Abstract

To provide a ball bearing in which a seal cannot easily fall off from a seal groove.SOLUTION: A first seal groove 18 of a ball bearing 10 has an inner protrusion 52, a first stepped face 53, an outer recessed part 54 and a second stepped face 55. A first seal 16 has a metal ring 21 and a rubber part 22 fitted in the first seal groove 18. The metal ring 21 has an annular ring part 26 and an outer end part 27 radially located outside. The outer end part 27 has a support piece 28 that is discontinuous in a circumferential direction. The rubber part has a rubber peripheral part 33, and a second rubber side part 32 that comes into contact with the second stepped face 55 over the entire circumference. The rubber outer peripheral part 33 has a groove 36 penetrating in an axial direction. In the outer end part 27, a discontinuous part, in which the support piece 28 is discontinuous, is located radially inside a first rubber portion 41 in which a groove 36 is formed, in the rubber outer peripheral part 33, and in the rubber outer peripheral part 33, the support piece 28 is located radially inside a second rubber portion 42 other than the first rubber portion 41.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a ball bearing. [Background technology]

[0002] Patent Document 1 discloses a ball bearing having a seal member. The seal member has a metal ring and a rubber part that is integral with the metal ring. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-35333 A Summary of the Invention [Problem to be solved by the invention]

[0004] 7 is a cross-sectional view of a conventional ball bearing having a seal member. The seal member 90 has a metal ring 91 and a rubber portion 92 that is integral with the metal ring 91. An outer portion 93 of the rubber portion 92 fits into a seal groove 98 of an outer ring 99 in an elastically deformed state. In this way, the seal member 90 is attached to the outer ring 99. The seal member 90 is not in contact with an inner ring 100. This ball bearing may be used with oil lubrication. Lubricating oil (oil) enters the bearing internal space surrounded by the outer ring 99, the inner ring 100, and the two seal members 90. It has been found that when the ball bearing rotates at high speed, there is a possibility that the seal member 90 may fall off from the seal groove 98. When the ball bearing rotates at high speed, the lubricating oil in the space inside the bearing is stirred, and the seal member 90 receives a force toward the outside in the axial direction (the side toward which it comes off) due to the stirring force and the centrifugal force acting on the lubricating oil. The outer part 93 of the rubber part 92 may succumb to this force and elastically deform, causing the seal member 90 to fall off from the seal groove 98.

[0005] SUMMARY OF THE PRESENT EMBODIMENTS Accordingly, an object of the present invention is to provide a ball bearing in which the seal is less likely to fall off the shield groove. [Means for solving the problem]

[0006] (1) A ball bearing of the present invention comprises an inner ring, an outer ring, a plurality of balls provided between the inner ring and the outer ring, and a first annular seal attached to a first axial side of the outer ring, the outer ring has a first seal groove for mounting the first seal on a first axial side, the first seal groove has an inner protruding portion located from a side surface on an axial first side of the outer ring to a second axial direction, a first step surface extending radially outward from the inner protruding portion, an outer recessed portion located on the second axial side from the first step surface and positioned radially outward from the inner protruding portion, and a second step surface extending radially inward from the outer recessed portion, the first seal has a metal ring and a rubber portion that is integral with the metal ring and fits into the first seal groove, The metal ring has a circular ring portion and a radially outer outer end portion continuous with the circular ring portion, The outer end portion has a support piece portion that is discontinuous in the circumferential direction and extends in the axial direction from the annular portion, the rubber portion has a rubber outer peripheral portion that covers the outer end portion from an outer peripheral side and fits into the outer recessed portion, and a second rubber side portion that covers the outer end portion from a second axial side and contacts the second step surface over an entire circumference, The rubber outer circumferential portion has a groove penetrating the rubber outer circumferential portion in the axial direction, a discontinuous portion, which is a portion of the outer end portion where the support piece portion is discontinuous, is located radially inside a first rubber portion, in which the groove is formed, of the rubber outer circumferential portion, The support piece portion is located radially inside a second rubber portion of the rubber outer circumferential portion other than the first rubber portion.

[0007] In the ball bearing having the above configuration, the outer end portion of the metal ring, where the support piece portion is discontinuous, is located radially inside the first rubber portion in which the groove is formed, of the rubber outer periphery. The groove is formed in the first rubber portion, and the portion located radially inside is not supported by the support piece portion, so it is prone to elastic deformation, and elastically deforms when the force received from the lubricating oil increases. Then, a gap is formed between the second rubber side portion located radially inside the first rubber portion and the second step surface. Since the groove is formed in the first rubber portion, the groove and the gap are connected, and the lubricating oil is discharged to the outside. In this way, when the force exerted by the lubricating oil on the first seal becomes large, the first seal discharges the lubricating oil to the outside, thereby releasing the force and preventing the lubricating oil from falling out of the first seal groove.

[0008] The support piece of the outer end of the metal ring supports a second rubber portion of the outer circumferential rubber portion that fits into the outer recess of the first seal groove. The second rubber portion is a portion other than the first rubber portion in which the groove is formed. Elastic deformation of the second rubber portion is suppressed by the support piece, making it difficult for the first seal to come out of the first seal groove.

[0009] (2) Preferably, the ball bearing has a second annular seal attached to a second axial side of the outer ring, the outer ring having a second seal groove on the second axial side for attaching the second seal, lubricating oil is stored in a bearing internal space formed between the first seal and the second seal, and when centrifugal force acts on the lubricating oil, the second rubber side portion present in the discontinuous portion elastically deforms, thereby connecting the groove to the bearing internal space and enabling the lubricating oil to be discharged from the space to the first axial side.

[0010] With this configuration, when the ball bearing rotates at high speed, the pressure of the lubricating oil increases in the space inside the bearing between the first seal and the second seal, on the inner periphery of the outer ring. When the pressure increases, the first seal releases the pressure by discharging the lubricating oil to the outside, preventing it from falling out of the first seal groove.

[0011] (3) Preferably, in the outer circumferential portion of the rubber, the first rubber portion in which the groove is formed occupies a smaller proportion in the circumferential direction than the second rubber portion. With the above configuration, when the force received from the lubricating oil becomes large, the first seal has the function of releasing the force by discharging the lubricating oil to the outside, thereby preventing the first seal from falling off, and since the second rubber portion supported by the support piece portion accounts for a large proportion in the circumferential direction, the first seal is less likely to fall off from the first seal groove.

[0012] (4) Preferably, the second rubber side portion, which is located radially inward of the first rubber portion, has an inner circumferential surface that is linear in the axial direction, and the groove has a groove bottom surface that extends radially outward as it approaches the first axial side. With this configuration, the portion of the first rubber portion where the groove is formed that is located radially inward is thinned, and this portion is prone to elastic deformation, and is prone to elastic deformation when the force applied from the lubricating oil increases. Effect of the Invention

[0013] According to the ball bearing of the present invention, a structure is obtained in which the seal is unlikely to fall off the seal groove. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a cross-sectional view showing an embodiment of a ball bearing according to the present invention. [Diagram 2] FIG. 2 is a cross-sectional view of the ball bearing shown in FIG. [Diagram 3] 3 is an enlarged cross-sectional view showing a portion of the outer ring shown in FIG. 1 on a first axial side. [Figure 4] 4 is an enlarged cross-sectional view showing a portion of the outer ring shown in FIG. 2 on a first axial side. [Diagram 5] FIG. 5 is an explanatory diagram showing a part of the outer end portion of the metal ring as viewed from the outer periphery side. [Figure 6] FIG. 6 is an explanatory view of the first seal as viewed from the second axial side. [Figure 7] FIG. 7 is a cross-sectional view of a conventional ball bearing having a seal member. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] [Overall structure of ball bearing] Fig. 1 is a cross-sectional view showing one embodiment of a ball bearing of the present invention. Fig. 2 is a cross-sectional view of the ball bearing shown in Fig. 1, but shows a cross-section at a different position from that in Fig. 1. A ball bearing 10 shown in Figs. 1 and 2 has an inner ring 11, an outer ring 12, a plurality of balls 13 provided between the inner ring 11 and the outer ring 12, a cage 14, an annular first seal 16, and an annular second seal 17. The outer ring 12 is fixed to a housing (not shown), and the inner ring 11 rotates together with a shaft (not shown). Fig. 1 shows a cross-section in a plane including a central axis C of the ball bearing 10.

[0016] The directions of the ball bearing 10 are defined below. The direction along the central axis C of the ball bearing 10 and the direction parallel to the central axis C are defined as the "axial direction." The direction perpendicular to the central axis C is defined as the "radial direction." The direction along a circle centered on the central axis C is defined as the "circumferential direction." In each figure, the right side is defined as the "first axial side" and the left side is defined as the "second axial side".

[0017] The cage 14 is annular and holds a number of balls 13 at intervals in the circumferential direction. The first seal 16 is attached to a first axial side of the outer ring 12. The first seal 16 is not in contact with the inner ring 11. The second seal 17 is attached to a second axial side of the outer ring 12. The second seal 17 is not in contact with the inner ring 11. The first seal 16 and the second seal 17 have the same structure. The first seal 16 and the second seal 17 are attached to the outer ring 12 in opposite directions.

[0018] The inner ring 11 has on its outer periphery, in order from the first axial side to the second axial side, a first groove 61, a first inner ring shoulder 62, an inner ring raceway groove 63, a second inner ring shoulder 64, and a second groove 65. The outer ring 12 has on its inner circumference, in order from the first axial side to the second axial side, a first seal groove 18, a first outer ring shoulder 66, an outer ring raceway groove 67, a second outer ring shoulder 68, and a second seal groove 19.

[0019] When the ball bearing 10 rotates, the multiple balls 13 held in the cage 14 roll and come into contact with the inner ring raceway groove 63 and the outer ring raceway groove 67 . The first groove 61 and the second groove 65 are symmetrical on the first axial side and the second axial side and have the same shape. The first seal groove 18 and the second seal groove 19 are symmetrical on the first axial side and the second axial side, and have the same shape.

[0020] The first seal groove 18 is provided on a first axial side of the outer ring 12, and is a circumferentially continuous groove for mounting the first seal 16. The first recessed groove 61 is a circumferentially continuous groove that receives a portion of the lip 37 of the first seal 16 and is not in contact with the lip 37. The second seal groove 19 is provided on a second axial side of the outer ring 12, and is a circumferentially continuous groove for mounting the second seal 17. The second recessed groove 65 is a circumferentially continuous groove that receives a portion of the lip 37 of the second seal 17 and is not in contact with the lip 37.

[0021] [Regarding the first seal groove 18] Fig. 3 is an enlarged cross-sectional view showing a portion of the first axial side of the outer ring 12 shown in Fig. 1. Fig. 4 is an enlarged cross-sectional view showing a portion of the first axial side of the outer ring 12 shown in Fig. 2. Figs. 3 and 4 show cross sections in a plane including the central axis C of the ball bearing 10 (see Figs. 1 and 2).

[0022] The first seal groove 18 has, in order from the first axial side toward the ball 13 side which is the second axial side, an inner protrusion 52, a first step surface 53, an outer recessed portion 54, and a second step surface 55. The inner protruding portion 52 is a portion that exists on the second axial side from the side surface 51 on the first axial side of the outer ring 12. The inner protruding portion 52 is a portion that protrudes radially inward compared to a groove bottom surface 54a, which will be described later, of the outer recessed portion 54.

[0023] The first step surface 53 is a surface extending radially outward from the inner protruding portion 52. In the case of the embodiment shown in Fig. 3 and Fig. 4, the first step surface 53 is a slope that extends radially outward and toward the second axial side. The outer recessed portion 54 is located on the second axial side from the first step surface 53 and is located radially outward from the inner protruding portion 52. The outer recessed portion 54 has a groove bottom surface 54a that is linear in the axial direction in the cross section shown in Figures 3 and 4. The groove bottom surface 54a is located radially outward from the inner protruding portion 52. The second step surface 55 is a surface that faces radially inward from the outer recessed portion 54. The second step surface 55 is a surface that faces a first side in the axial direction. The second step surface 55 is an annular surface that is continuous in the circumferential direction.

[0024] [Regarding First Seal 16] 1 and 2, the first seal 16 has a metal ring 21 and a rubber portion 22 that is integral with the metal ring 21. The rubber portion 22 fits into the first seal groove 18, thereby attaching the first seal 16 to the outer ring 12. The metal ring 21 is made of metal and is manufactured by pressing. The rubber portion 22 is made of rubber and is elastically deformable. The rubber portion 22 is bonded to the metal ring 21 by vulcanization.

[0025] The metal ring 21 has an annular portion 26 and an outer end portion 27 on the radially outer side that is continuous with the annular portion 26. As shown in Fig. 3, the outer end portion 27 has a plurality of support piece portions 28 that are provided extending in the axial direction from the annular portion 26. As shown in Figs. 3, 4, and 5, the support piece portions 28 are not continuous in the circumferential direction, but are discontinuous in the circumferential direction. Fig. 5 is an explanatory diagram of a part of the outer end portion 27 of the metal ring 21 as viewed from the outer periphery side.

[0026] The outer end portion 27 has a cutout portion 29. The cutout portion 29 is provided between two support piece portions 28 adjacent to each other in the circumferential direction. The outer end portion 27 has a plurality of cutout portions 29. For example, the outer end portion 27 has four cutout portions 29 spaced apart in the circumferential direction. The cutout portions 29 all have the same shape.

[0027] The length L1 along the circumferential direction of one cutout portion 29 is overwhelmingly smaller than the length L2 along the circumferential direction of one support piece portion 28. The angle of the range occupied by one cutout portion 29 about the central axis C (see FIG. 6) is, for example, 3 to 10 degrees. The portion where there are no cutout portions 29 in the circumferential direction is the support piece portion 28. FIG. 6 is an explanatory diagram of the first seal 16 as viewed from the second axial side. As described above, the outer end portion 27 of the metal ring 21 located on the radially outer side has a plurality of support piece portions 28 and a plurality of cutout portions 29.

[0028] 3, the support piece portion 28 is provided to extend toward a second axial side from a radially outer end 26a of the annular portion 26. The support piece portion 28 has a shape along an imaginary cylinder centered on the central axis C (see FIG. 1). The support piece portion 28 is located radially closer to the inner circumferential surface 66a of the first outer race shoulder 66 than to the outer recessed portion 54. The radially inner side surface 28a of the support piece portion 28 and the inner circumferential surface 66a of the first outer race shoulder 66 are located close to each other in the radial direction.

[0029] In the case of the embodiment shown in Fig. 4, the outer end portion 27 has a plate piece portion 30 that extends slightly toward the second axial direction side from the radially outer end 26a of the annular portion 26 in the region where the cutout portion 29 is formed. The plate piece portion 30 is shorter than the support piece portion 28 (see Figs. 3 and 5). The plate piece portion 30 may be omitted.

[0030] 3 and 4, the rubber portion 22 has, on the radially outer side, a first rubber side portion 31, a second rubber side portion 32, and a rubber outer circumferential portion 33. The first rubber side portion 31, the second rubber side portion 32, and the rubber outer circumferential portion 33 are each continuous in the circumferential direction and have an annular shape. The rubber outer circumferential portion 33 is continuous with the first rubber side portion 31 and the second rubber side portion 32. The rubber portion 22 has a rubber inner peripheral portion 34 on the radially inner side (see Figs. 1 and 2). The rubber portion 22 has a third rubber side portion 35 that connects the rubber inner peripheral portion 34 and the first rubber side portion 31. The rubber inner peripheral portion 34 and the third rubber side portion 35 are each continuous in the circumferential direction and have annular shapes.

[0031] As shown in Figs. 3 and 4, the first rubber side portion 31 is a portion that covers the outer end portion 27 from a first side in the axial direction. The second rubber side portion 32 covers the end face 28b on the second axial side of the support piece portion 28 (see FIG. 3), and is in a state of being inserted into the notch portion 29 (see FIG. 4) to cover the plate piece portion 30 from the second axial side. The second rubber side portion 32 covering the end face 28b of the support piece portion 28 (see FIG. 3) and the second rubber side portion 32 present in the notch portion 29 (see FIG. 4) are continuous in the circumferential direction. In other words, the second rubber side portion 32 covers the entire circumference of the outer end portion 27 from the second axial side. The second rubber side portion 32 contacts the second step surface 55 over the entire circumference.

[0032] The rubber outer peripheral portion 33 is a portion that covers the outer end portion 27 from the outer periphery side. As shown in Fig. 3, the rubber outer peripheral portion 33 fits into the outer recessed portion 54 in an elastically compressed and deformed state. The rubber outer peripheral portion 33 has a portion that is elastically compressed and deformed in the axial direction while being sandwiched between the first step surface 53 and the second step surface 55. The rubber outer peripheral portion 33 is elastically compressed and deformed in the radial direction while being sandwiched between the outer recessed portion 54 and the support piece portion 28 of the metal ring 21.

[0033] The rubber outer circumferential portion 33 has grooves 36 (see Figs. 4 and 6). The grooves 36 are provided partially in the rubber outer circumferential portion 33. The number of the grooves 36 is the same as the number of the cutout portions 29 in the metal ring 21. The grooves 36 all have the same shape. The groove 36 opens radially outward. As shown in Fig. 4, the groove 36 opens at a side surface on a first axial direction side of the rubber outer circumferential portion 33, and further opens at a side surface on a second axial direction side of the rubber outer circumferential portion 33. In other words, the groove 36 penetrates the rubber outer circumferential portion 33 in the axial direction.

[0034] 6, the circumferential positions of the grooves 36 coincide with the circumferential positions of the cutout portions 29 of the metal ring 21. For example, when the four cutout portions 29 are arranged at equal intervals in the circumferential direction, the four grooves 36 are also arranged at equal intervals in the circumferential direction and at the same circumferential positions as the cutout portions 29.

[0035] A length L4 (see FIG. 6) of the cutout portion 29 along the circumferential direction is greater than a length L3 (see FIG. 6) of the groove 36 along the circumferential direction. The circumferential length L4 of the cutout portion 29 may be the same as the circumferential length L3 of the groove 36, or the circumferential length L4 of the cutout portion 29 may be smaller than the circumferential length L3 of the groove 36.

[0036] Of the rubber outer periphery 33, a portion in which the groove 36 is formed is defined as a "first rubber portion 41." Of the rubber outer periphery 33, a portion in which the groove 36 is not formed, i.e., a portion other than the first rubber portion 41, is defined as a "second rubber portion 42." The range of the length L3 of one groove 36, that is, the angle of the first rubber portion 41, is, for example, 3 to 10 degrees about the central axis C.

[0037] 4, the second rubber side portion 32 located radially inside the first rubber portion 41 has an inner circumferential surface 38 that is linear in the axial direction. The groove 36 has a groove bottom surface 37 that extends radially outward toward the first axial side.

[0038] As shown in Figures 4 and 6, the cutout portion 29, which is the portion (discontinuous portion) of the outer end portion 27 of the metal ring 21 where the support piece portion 28 is discontinuous, is located radially inside the first rubber portion 41 in the rubber outer periphery 33 in which the groove 36 is formed. As shown in FIGS. 3 and 6, the support piece portion 28 is located on the radially inner side of a second rubber portion 42 other than the first rubber portion 41 of the rubber outer circumferential portion 33.

[0039] As described above (see FIG. 5), the length L1 of the cutout portion 29 in the circumferential direction is overwhelmingly smaller than the length L2 of the support piece portion 28 in the circumferential direction. As shown in FIG. 6, the groove 36 and the cutout portion 29 are disposed at the same position in the circumferential direction. The range of the length L3 of one groove 36, that is, the angle of the first rubber portion 41, about the central axis C, is, for example, 3 to 10 degrees. Therefore, in the rubber outer circumferential portion 33, the first rubber portion 41 in which the groove 36 is formed occupies a smaller proportion in the circumferential direction than the second rubber portion 42.

[0040] 1 and 2, the rubber inner peripheral portion 34 is a portion that covers the inner end portion 45 of the metal ring 21. The rubber inner peripheral portion 34 has a lip 37 that extends radially inward. The lip 37 is not in contact with the inner ring 11, and there is a gap between the lip 37 and the inner ring 11 (first groove 61). The third rubber side portion 35 covers the annular portion 26 of the metal ring 21 from the first axial side, and connects the first rubber side portion 31 and the inner circumferential rubber portion 34 together.

[0041] [Regarding the second seal 17] As described above, the mounting orientation of the first seal 16 and the mounting orientation of the second seal 17 are opposite, but the configuration of the first seal 16 and the configuration of the second seal 17 are the same. A detailed description of the second seal 17 will be omitted. In Fig. 1 and Fig. 2, the reference numerals of the components of the second seal 17 are the same as the reference numerals of the components of the first seal 16.

[0042] [Regarding the ball bearing 10 of this embodiment] As described above, ball bearing 10 of this embodiment (see FIGS. 1 and 2) has inner ring 11, outer ring 12, multiple balls 13, first seal 16, second seal 17, and cage 14. Outer ring 12 has a first seal groove 18 for mounting first seal 16 on a first axial side. Outer ring 12 has a second seal groove 19 for mounting second seal 17 on a second axial side.

[0043] The first seal groove 18 has an inner protruding portion 52 , a first step surface 53 , an outer recessed portion 54 , and a second step surface 55 . The first seal 16 has a metal ring 21 and a rubber portion 22 that is integral with the metal ring 21 and fits into the first seal groove 18. The metal ring 21 has an annular portion 26 and an outer end portion 27 that is continuous with the annular portion 26 and is located radially outward. As shown in Figures 3, 4, 5 and 6, the outer end portion 27 has a plurality of support piece portions 28 that extend axially from the annular portion 26. The support piece portions 28 are provided discontinuously in the circumferential direction.

[0044] The rubber portion 22 (see Figs. 3 and 4) has a rubber outer peripheral portion 33 that covers the outer end portion 27 from the outer peripheral side, and a second rubber side portion 32 that covers the outer end portion 27 from a second axial side. The rubber outer peripheral portion 33 fits into the outer recessed portion 54. The second rubber side portion 32 contacts the second step surface 55 over the entire circumference. The rubber outer peripheral portion 33 has a groove 36 that penetrates the rubber outer peripheral portion 33 in the axial direction.

[0045] As shown in FIG. 4, the cutout portion 29, which is the portion (discontinuous portion) of the outer end portion 27 where the support piece portion 28 is discontinuous, is located radially inside the first rubber portion 41 in the rubber outer circumferential portion 33 in which the groove 36 is formed. As shown in FIG. 3, the support piece portion 28 is located on the radially inner side of a second rubber portion 42 that is other than the first rubber portion 41 of the rubber outer circumferential portion 33.

[0046] 1 and 2, lubricating oil is present in the bearing internal space between inner ring 11 and outer ring 12 in which balls 13 exist. The lubricating oil is stored in the bearing internal space formed between first seal 16 and second seal 17. When ball bearing 10 rotates, the lubricating oil in the bearing internal space is stirred, and the first seal 16 and second seal 17 each receive a force toward the outside in the axial direction (the side toward which they are removed) due to the stirring force and the centrifugal force acting on the lubricating oil. In particular, when ball bearing 10 rotates at high speed, the force that first seal 16 and second seal 17 receive from the lubricating oil becomes large.

[0047] Therefore, according to the ball bearing 10 having the above-mentioned configuration (see FIG. 4), the cutout portion 29 at which the support piece portion 28 is discontinuous in the outer end portion 27 of the metal ring 21 is located radially inside the first rubber portion 41 in which the groove 36 is located, in the rubber outer circumferential portion 33. The groove 36 is provided in the first rubber portion 41, and the portion located radially inside thereof (the second rubber side portion 32) is not supported by the support piece portion 28. For this reason, the portion (the second rubber side portion 32) is easily elastically deformed, and is elastically deformed when the force applied to the portion (the second rubber side portion 32) from the lubricating oil increases.

[0048] When the ball bearing 10 is not rotating or is rotating at a low speed, the second rubber side portion 32 is in contact with the second step surface 55 over the entire circumference. In contrast, when the ball bearing 10 is rotating at a particularly high speed, the portion (second rubber side portion 32) located radially inward of the first rubber portion 41 is subjected to force from the lubricating oil and elastically deforms radially outward toward the first axial side. Then, a gap is formed between the second rubber side portion 32 and the second step surface 55. Since the groove 36 is formed in the first rubber portion 41, the groove 36 and the gap are connected, and the lubricating oil is moved radially outward by centrifugal force, and the lubricating oil is discharged to the outside.

[0049] Thus, with ball bearing 10 having the above configuration, when centrifugal force acts on the lubricating oil, second rubber side portion 32 present in the discontinuous portion (cutout portion 29) where support piece portion 28 is discontinuous elastically deforms, and groove 36 communicates with the bearing internal space, making it possible to discharge the lubricating oil from that space to the first axial direction side. In other words, when the force received from the lubricating oil becomes large, first seal 16 discharges the lubricating oil to the outside, thereby relieving the force and preventing it from falling out of first seal groove 18.

[0050] In the present embodiment (see FIG. 4), the second rubber side portion 32 located radially inside the first rubber portion 41 has an inner circumferential surface 38 that is linear in the axial direction. The groove 36 has a groove bottom surface 37 that extends radially outward toward the first axial side. With this configuration, the portion of the first rubber portion 41 where the groove 36 is formed that is located radially inside is thin. The second rubber side portion 32 corresponding to this portion is prone to elastic deformation, and is prone to elastic deformation when the force received from the lubricating oil increases.

[0051] 3, the second rubber portion 42 of the rubber outer circumferential portion 33 is fitted into the outer recessed portion 54 of the first seal groove 18. The support piece portion 28 of the outer end portion 27 of the metal ring 21 supports the second rubber portion 42. Therefore, the elastic deformation of the second rubber portion 42 is suppressed by the support piece portion 28, and the first seal 16 becomes difficult to come out of the first seal groove 18.

[0052] In the case of this embodiment, as described above (see FIG. 4), the first rubber portion 41 in which the groove 36 is formed occupies a smaller proportion of the circumferential area of ​​the rubber outer circumferential portion 33 than the second rubber portion 42. Therefore, when the force applied to the first seal 16 from the lubricating oil increases, the first seal 16 has the function of releasing the force by discharging the lubricating oil to the outside, thereby preventing the first seal 16 from falling off. At the same time, the proportion of the second rubber portion 42 supported by the support piece portion 28 in the circumferential area is large, so that the first seal 16 is less likely to fall off the first seal groove 18.

[0053] The second seal 17 has the same structure as the first seal 16, and therefore has the above-mentioned falling-off prevention function.

[0054] 〔others〕 The embodiments disclosed herein are illustrative and not restrictive in all respects. The scope of the present invention is not limited to the above-described embodiments, but includes all modifications within the scope of the equivalents of the configurations described in the claims. [Explanation of symbols]

[0055] 10 ball bearings 11. Inner Circle 12 Outer ring 13 balls 16 First Seal 18 First seal groove 21 Metal ring 22 Rubber part 26 Circular Ring 27 Outer end 28 Support piece 29 Cutout (discontinuous) 32 Second rubber side 33 Rubber outer periphery 36 Groove 37 Groove bottom surface 38 Inner surface 41 First rubber part 42 Second rubber part 51 Side 52 Inner protrusion 53 First stage surface 54 Outer recess 54a Groove bottom surface 55 Second stage surface

Claims

1. The bearing comprises an inner ring, an outer ring, a plurality of balls disposed between the inner ring and the outer ring, and an annular first seal attached to a first axial side of the outer ring, the outer ring has a first seal groove for mounting the first seal on a first axial side, The first seal groove is an inner protruding portion located on a second axial side from a side surface on a first axial side of the outer ring; A first step surface extending radially outward from the inner protruding portion; an outer recessed portion located on a second axial side from the first step surface and positioned radially outward from the inner protruding portion; A second step surface extending radially inward from the outer recessed portion; having the first seal has a metal ring and a rubber portion that is integral with the metal ring and fits into the first seal groove, The metal ring has a circular ring portion and a radially outer outer end portion continuous with the circular ring portion, The outer end portion has a support piece portion that is discontinuous in the circumferential direction and extends in the axial direction from the annular portion, the rubber portion has a rubber outer peripheral portion that covers the outer end portion from an outer peripheral side and fits into the outer recessed portion, and a second rubber side portion that covers the outer end portion from a second axial side and contacts the second step surface over the entire circumference, The rubber outer circumferential portion has a groove penetrating the rubber outer circumferential portion in the axial direction, a discontinuous portion, which is a portion of the outer end portion where the support piece portion is discontinuous, is located radially inside a first rubber portion, in which the groove is formed, of the rubber outer circumferential portion, The support piece portion is located radially inside a second rubber portion other than the first rubber portion of the rubber outer circumferential portion. ball bearings.

2. a second annular seal attached to a second axial side of the outer ring; the outer ring has a second seal groove on a second axial side for mounting the second seal, The lubricating oil is stored in a bearing internal space formed between the first seal and the second seal, When a centrifugal force acts on the lubricating oil, the second rubber side portion present in the discontinuous portion is elastically deformed, so that the groove communicates with the bearing internal space, and the lubricating oil can be discharged from the space to the first axial direction.

2. A ball bearing according to claim 1.

3. In the rubber outer circumferential portion, the first rubber portion in which the groove is formed has a smaller circumferential proportion than the second rubber portion.

3. A ball bearing according to claim 1 or 2.

4. The second rubber portion, which is located radially inside the first rubber portion, has an inner circumferential surface that is linear in the axial direction, 3. The ball bearing according to claim 1, wherein the groove has a groove bottom surface that extends radially outwardly toward a first axial side.

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