Ball bearing

Abstract

To prevent a lubricant in a bearing internal space from flowing out to the outside through a gap between a seal groove and a seal of an outer ring because the seal cannot easily fall off from the seal groove.SOLUTION: An outer ring 12 has a first seal groove 18 for mounting a first seal 16. The first seal groove 18 has an inner protrusion 52, a first stepped face 53, an outer recessed part 54 and a second stepped face 55. The first seal 16 has a metal ring 21 and a rubber part 22. The metal ring 21 has an annular ring part 26 and an outer end part 27. The outer end part 27 has a fitting part 28 fitted in the first seal groove 18, and a defective part 29 partially disposed in a circumferential direction. The rubber part 22 has a first rubber part 31, a second rubber part 32 that comes into contact with the second stepped face 55 over the entire circumference, and a third rubber part 33 that is located in the defective part 29 and connects the first rubber part 31 and the second rubber part 32. The fitting part 28 is located radially outward from the inner protrusion 52, and also located in a range in an axial direction of the first stepped face 53 and the outer recessed part 54.SELECTED DRAWING: Figure 2

Description

[Technical field]

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

[0002] Patent Document 1 discloses a ball bearing having a shield (oil retaining plate). The shield has a function of preventing lubricating oil in the internal space of the bearing from leaking out to the outside of the bearing. The shield is manufactured by pressing a metal plate. Patent Document 2 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 2009-275799 A [Patent Document 2] JP 2016-35333 A Summary of the Invention [Problem to be solved by the invention]

[0004] 9 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] 10 is a cross-sectional view of a conventional ball bearing having a metallic shield. An outer portion 96 of a shield 95 fits into a shield groove 98 of an outer ring 99. In this way, the shield 95 is attached to the outer ring 99. Even if the ball bearing rotates at high speed and the shield 95 is subjected to a force exerted by the lubricating oil (oil) toward the axial outward (detaching) direction, as described above, the outer portion 96 remains fitted in the seal groove 98, and the shield 95 is prevented from falling off. However, there is a possibility that the lubricating oil may leak out between the outer portion 96 and the seal groove 98. In particular, in the case of high speed rotation, the lubricating oil subjected to centrifugal force is highly likely to leak out between the outer portion 96 and the seal groove 98.

[0006] Therefore, an object of the present invention is to provide a ball bearing in which the seal is less likely to fall off the seal groove and which prevents lubricating oil in the internal space of the bearing from leaking to the outside through the gap between the seal and the seal groove of the outer ring. [Means for solving the problem]

[0007] (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 integral with the metal ring, 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 fitting portion extending from the second axial side to the first axial side and fitting into the first seal groove, and a missing portion partially provided in a circumferential direction, the rubber portion includes a first rubber portion located on a first axial side of the outer end portion and having an annular shape along the metal ring, a second rubber portion located on a second axial side of the outer end portion and in contact with the second step surface over an entire circumference, and a third rubber portion located in the missing portion and connecting the first rubber portion and the second rubber portion, The fitting portion is located radially outward from the inner protruding portion and within the axial range of the first step surface and the outer recessed portion.

[0008] In the ball bearing having the above-described configuration, the second rubber portion of the rubber portion of the first seal contacts the second step surface of the first seal groove over the entire circumference, which makes it possible to prevent lubricating oil in the internal space of the bearing from leaking out through the gap between the first seal and the outer ring. The first seal has a metal ring whose outer end has a fitting portion extending from the second axial side to the first axial side. The fitting portion is located radially outward of the inner protrusion of the first seal groove and within the axial range of the first step surface and the outer recess. Therefore, even if the first seal attempts to fall off toward the first axial side, the fitting portion prevents the first seal from falling off. The outer end of the metal ring of the first seal has a cutout portion, and the third rubber portion is located in the cutout portion and connects the first rubber portion and the second rubber portion, so that the bonding strength between the metal ring and the rubber portion is high.

[0009] (2) Preferably, the fitting portion has an end surface on a first axial side that contacts the first step surface. In this case, when the first seal attempts to fall off toward the first side in the axial direction, the end face of the fitting portion comes into contact with the first step surface of the first seal groove, preventing the first seal from falling off.

[0010] (3) In the ball bearing according to (1) or (2) above, the first seal is preferably not in contact with the inner ring. In this case, the lubricating oil is permitted to infiltrate into the bearing internal space from between the first seal and the inner ring. The first seal prevents the lubricating oil that has infiltrated into the bearing internal space from flowing out to the first axial side. Even if the amount of lubricating oil is small, the lubricating oil is retained in the bearing internal space.

[0011] (4) In any one of the ball bearings (1) to (3), preferably, the outer end portion has an annular connecting portion extending radially outward from the annular portion and connected to the fitting portion, the connecting portion having a through hole as the missing portion, and the third rubber portion is provided in the through hole and connects the first rubber portion and the second rubber portion. With this structure, the bonding strength between the metal ring and the rubber portion is high.

[0012] (5) In any one of the ball bearings (1) to (3), preferably, the outer end has connecting piece portions that are spaced apart in the circumferential direction, extend radially outward from the annular portion and connect to the fitting portion, the outer end has a notch portion as the missing portion, the notch portion being provided between two circumferentially adjacent connecting piece portions, and the third rubber portion spans the notch portion and connects the first rubber portion and the second rubber portion. With this structure, the bonding strength between the metal ring and the rubber portion is high.

[0013] (6) In the ball bearing of any one of (1) to (5) above, the fitting portion preferably has, on its radially inner side, an exposed surface that is not covered by the rubber portion. According to the above configuration, in order to fit the fitting portion into the first seal groove, a jig is brought into contact with the exposed surface of the fitting portion, and the fitting portion is plastically deformed radially outward using the jig. As a result, the fitting portion is positioned radially outward from the inner protrusion. Since the fitting portion is plastically deformed to fit into the first seal groove, damage to the rubber portion can be prevented. Effect of the Invention

[0014] According to the ball bearing of the present invention, the seal is less likely to fall off from the seal groove, making it possible to prevent lubricating oil in the internal space of the bearing from leaking out to the outside through the gap between the seal and the seal groove of the outer ring. [Brief description of the drawings]

[0015] [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 an enlarged cross-sectional view showing a portion of the outer ring on a first axial side. [Diagram 3] FIG. 3 is an explanatory diagram of a part of the metal ring as viewed from a first axial side. [Figure 4] FIG. 4 is a cross-sectional view showing a state before the first seal is attached. [Diagram 5] FIG. 5 is a cross-sectional view showing a state in the middle of attaching the first seal. [Figure 6] FIG. 6 is an enlarged cross-sectional view showing a portion of the outer ring on a first axial side. [Figure 7] FIG. 7 is an enlarged cross-sectional view showing a portion of the outer ring on a first axial side. [Figure 8] FIG. 8 is an explanatory diagram of a part of the metal ring as viewed from a first axial side. [Figure 9] FIG. 9 is a cross-sectional view of a conventional ball bearing having a seal member. [Figure 10] FIG. 10 is a cross-sectional view of a conventional ball bearing having a shield. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] [Overall structure of ball bearing] Fig. 1 is a cross-sectional view showing one embodiment of a ball bearing of the present invention. The ball bearing 10 shown in Fig. 1 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 of the ball bearing 10 taken along a plane including a central axis C.

[0017] 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".

[0018] 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.

[0019] 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.

[0020] 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.

[0021] 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.

[0022] [Regarding the first seal groove 18] Fig. 2 is an enlarged cross-sectional view showing a part of the axial first side of the outer ring 12. Fig. 2 shows a cross section taken along a plane including the central axis C of the ball bearing 10 (see Fig. 1). 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. 2, the first step surface 53 is an inclined surface extending radially outward and extending 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 Figure 2. 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] As described above, the first seal 16 and the second seal 17 are attached in opposite directions but have the same structure. As shown in Fig. 1, the first seal 16 has a metal ring 21 and a rubber part 22 that is integral with the metal ring 21. The metal ring 21 is made of metal and manufactured by pressing. The rubber part 22 is made of rubber and is elastically deformable. The rubber part 22 is bonded to the metal ring 21 by vulcanization.

[0025] The metal ring 21 has an annular portion 26, an outer end portion 27, and an inner end portion 45. The annular portion 26 has an annular shape. The outer end portion 27 is a radially outer portion of the metal ring 21, and is continuous with a radially outer end 26a (see FIG. 2) of the annular portion 26. In the case of the embodiment shown in FIG. 2, the outer end portion 27 has a fitting portion 28 and a connecting portion 30.

[0026] The fitting portion 28 is a portion that fits into the first seal groove 18. As will be described later, when the first seal 16 is attached to the outer ring 12, the fitting portion 28 is plastically deformed radially outward and is crimped into the first seal groove 18.

[0027] The connecting portion 30 is annular, and extends radially outward from the annular portion 26 to connect with the fitting portion 28. The connecting portion 30 has an inclined tube portion 46 and an intermediate portion 47. The inclined tube portion 46 has a shape along a truncated cone that starts from the radially outer end 26a of the annular portion 26 and faces the second axial side as it moves radially outward. In the cross section shown in FIG. 2, the intermediate portion 47 is linear along the radial direction and is short in the radial direction. The intermediate portion 47 may be annular, or may be non-annular and discontinuous in the circumferential direction, similar to the fitting portion 28 (as will be described later with reference to FIG. 3).

[0028] The fitting portion 28 is a portion extending in the axial direction from the radially outer end 47a of the intermediate portion 47. The fitting portion 28 has a shape extending from the second axial side to the first axial side. The fitting portion 28 has a shape along a virtual cylinder that is short in the axial direction. However, as shown in FIG. 3, the fitting portion 28 is not annular, but is provided discontinuously in the circumferential direction. FIG. 3 is an explanatory diagram of the metal ring 21 as viewed from the first axial side. The outer end portion 27 has one common connecting portion 30 and a plurality of fitting portions 28 that are provided extending from the connecting portion 30, exist independently, and are independently deformable.

[0029] The fitting portion 28 (see FIG. 2 ) has an end face 28a on a first axial side that contacts the first step surface 53. When the first seal 16 is attached to the first seal groove 18, the end face 28a may be in contact with the first step surface 53. Alternatively, when the first seal 16 is attached to the first seal groove 18, a gap may be provided between the end face 28a and the first step surface 53, and when a force toward the first axial side acts on the first seal 16, the end face 28a may be in contact with the first step surface 53. The first step surface 53 receives the force toward the first axial side acting on the first seal 16 from the fitting portion 28.

[0030] The outer end portion 27 has a cutout portion 29 that is partially provided in the circumferential direction. In the case of the embodiment shown in Fig. 2, the outer end portion 27 has a through hole 40 as the cutout portion 29. The through hole 40 is provided in the inclined cylindrical portion 46 of the connecting portion 30. The through hole 40 penetrates the plate-shaped metal ring 21 in the plate thickness direction. The connecting portion 30 (the inclined tube portion 46) is continuous in the circumferential direction and has an annular shape. The through holes 40 are provided at a plurality of locations along the circumferential direction in the connecting portion 30 (the inclined tube portion 46) (see FIG. 3). In this manner, the connecting portion 30 has the through holes 40 as the missing portion 29.

[0031] 1, the inner end portion 45 is a radially inner portion of the metal ring 21, and is continuous with the radially inner end of the annular portion 26. The inner end portion 45 has a shape that is inclined toward the second axial side (the side of the balls 13) as it extends radially inward. The inner end portion 45 is covered by the fourth rubber portion 34, which will be described later.

[0032] The rubber portion 22 has a first rubber portion 31, a second rubber portion 32, and a third rubber portion 33 on the radially outer side (see FIG. 2). The rubber portion 22 has a fourth rubber portion 34 on the radially inner side (see FIG. 1). The rubber portion 22 has a fifth rubber portion 35 that connects the first rubber portion 31 and the fourth rubber portion 34.

[0033] In FIG. 2, the first rubber portion 31 is located on a first axial side of the outer end portion 27. The first rubber portion 31 is annular along the metal ring 21. The first rubber portion 31 covers the inclined tube portion 46 from the first axial side. The first rubber portion 31 does not cover the entire intermediate portion 47 from the first axial side. The intermediate portion 47 is exposed to the first axial side. The first rubber portion 31 does not cover the fitting portion 28. The fitting portion 28 is exposed radially inward. In other words, the fitting portion 28 has an exposed surface 43 on its radially inner side that is not covered by the rubber portion 22.

[0034] The second rubber portion 32 is located on a second axial side of the outer end portion 27. The second rubber portion 32 is annular along the metal ring 21. The second rubber portion 32 contacts the second step surface 55 over the entire circumference. With the first seal 16 attached to the first seal groove 18, the second rubber portion 32 is in a state of being elastically compressed and deformed in the axial direction. The second rubber portion 32 covers the inclined tube portion 46 and the intermediate portion 47 from the second axial side. The second rubber portion 32 covers the radially outer side surface 28b of the fitting portion 28 in an annular shape from the radially outer side. The portion covering the radially outer side of the second rubber portion 32 includes a surface whose outer circumferential surface expands toward the second axial side and a chamfer that reduces in diameter from a conical surface before the fitting portion 28 is attached to the first seal groove 18, and when the fitting portion 28 is attached to the first seal groove 18, the expanding surface comes into close contact with the groove bottom surface 54a of the outer recessed portion 54 due to deformation of the metal ring 21 and deformation of the expanding surface. In this embodiment, the expanding surface is a conical surface before the fitting portion 28 is attached to the first seal groove 18. The second rubber portion 32 may be configured to cover the radially outer surface 28b of the fitting portion 28 from the radial outside, or may be configured not to cover the fitting portion 28 but to expose the radially outer surface 28b of the fitting portion 28. It should be noted that the end surface 28a of the fitting portion 28 is not covered by the rubber portion 22 (the first rubber portion 31 and the second rubber portion 32).

[0035] When the second rubber portion 32 covers the radially outer surface 28b of the fitting portion 28, the fitting portion 28 presses the groove bottom surface 54a of the outer recess portion 54 radially outward via a part of the second rubber portion 32 (the part covering the radially outer surface 28b). When the second rubber portion 32 does not cover the radially outer surface 28b of the fitting portion 28, the fitting portion 28 is in direct contact with the groove bottom surface 54a of the outer recess portion 54, and presses the outer recess portion 54 radially outward.

[0036] The third rubber portion 33 is a portion located in the through hole 40 (the cutout portion 29). The third rubber portion 33 connects the first rubber portion 31 and the second rubber portion 32. In the case of the embodiment shown in Fig. 2, since the cutout portion 29 is the through hole 40, the third rubber portion 33 is in a state of being inserted in the through hole 40, and connects the first rubber portion 31 and the second rubber portion 32 in the axial direction.

[0037] The fourth rubber portion 34 (see FIG. 1) is a portion that covers the inner end portion 45 of the metal ring 21. The fourth rubber portion 34 has a lip 37 that extends radially inward. The lip 37 is not in contact with the inner ring 11, and a gap is provided between the lip 37 and the inner ring 11 (first groove 61). The fifth rubber portion 35 covers the annular portion 26 of the metal ring 21 from the first axial side, and connects the first rubber portion 31 and the fourth rubber portion 34 together.

[0038] [Installation of the first seal 16] A means for mounting the first seal 16 having the above configuration to the first seal groove 18 will now be described. Fig. 4 shows the state before mounting of the first seal 16. In the state before mounting, the outer diameter of the outermost diameter portion (the radially outer surface 28b of the fitting portion 28) of the first seal 16 is equal to or smaller than the inner diameter of the inner protruding portion 52. The first seal 16 is brought close to the first seal groove 18 from the first axial side, and the second rubber portion 32 comes into contact with the second step surface 55 (see Fig. 5).

[0039] 5, in order to fit the fitting portion 28 into the first seal groove 18, a jig 70 is brought into contact with the exposed surface 43 located on the radially inner side of the fitting portion 28. The fitting portion 28 is plastically deformed radially outward using the jig 70. Due to the contact of the jig 70, the fitting portion 28 has, on its radially inner side, an exposed surface 43 that is not covered by the rubber portion 22. Furthermore, the intermediate portion 47 is also exposed to the first axial side.

[0040] As described above (see FIG. 3), the fitting portion 28 is not annular, but is provided discontinuously in the circumferential direction, and the multiple fitting portions 28 can be deformed independently. Therefore, the plastic deformation of the fitting portion 28 is easy, the fitting portion 28 is plastically deformed with good precision, and each of the multiple fitting portions 28 is in a state of pressing the outer recess portion 54.

[0041] 2, fitting portion 28 has a portion located radially outward from inner protrusion 52. Fitting portion 28 has exposed surface 43, and jig 70 can press exposed surface 43 radially outward. Since exposed surface 43 is free of rubber portion 22, jig 70 can be prevented from damaging rubber portion 22 when fitting fitting portion 28 into first seal groove 18 through plastic deformation.

[0042] In the manner described above, when the first seal 16 is installed in the first seal groove 18, the fitting portion 28 is positioned radially outward from the inner protrusion portion 52 and within the axial range of the first step surface 53 and the outer recess portion 54.

[0043] [Other configurations of the first seal 16] Figures 6 and 7 are enlarged cross-sectional views showing a portion of the first axial side of the outer ring 12. Figure 6 shows a cross-section in a plane including the central axis C (see Figure 1) of the ball bearing 10. Figure 7 shows a cross-section in a plane including the central axis C of the ball bearing 10, but is a cross-sectional view in a different plane from that in Figure 6. 6 and 7, the outer end portion 27 has a fitting portion 28 and a connecting piece portion 41. The fitting portion 28 is the same as the fitting portion 28 shown in FIG.

[0044] The connecting piece portions 41 are provided at intervals in the circumferential direction, and extend radially outward from the annular portion 26 to connect with the fitting portion 28 (see Figs. 6 and 8). Fig. 8 is an explanatory diagram of a part of the metal ring 21 as viewed from the first axial side. As shown in Fig. 6, the cross-sectional shape of the connecting piece portion 41 is the same as the cross-sectional shape of the connecting portion 30 in the first embodiment shown in Fig. 2. However, in the case of the second embodiment shown in Fig. 6, the connecting piece portion 41 is not annular, but is provided discontinuously in the circumferential direction (see Fig. 8). For this reason, as shown in Figs. 7 and 8, the outer end portion 27 has a cutout portion 42 provided between two connecting piece portions 41 adjacent to each other in the circumferential direction as the missing portion 29.

[0045] In the case of the second embodiment shown in Fig. 7, the third rubber portion 33 connects the first rubber portion 31 and the second rubber portion 32 across the cutout portion 42. The third rubber portion 33 exists within the range of the cutout portion 42 (see Fig. 7), but does not exist in the region of the connecting piece portion 41 other than the cutout portion 42 (see Fig. 6).

[0046] In the second embodiment, the rubber portion 22 also has a first rubber portion 31, a second rubber portion 32, and a third rubber portion 33 on the radially outer side (see Figs. 6 and 7). The rubber portion 22 has a fourth rubber portion 34 on the radially inner side (see Fig. 1). The rubber portion 22 has a fifth rubber portion 35 that connects the first rubber portion 31 and the fourth rubber portion 34. The first rubber portion 31 is located on a first axial side of the outer end portion 27. The first rubber portion 31 is annular along the metal ring 21. The second rubber portion 32 is located on a second axial side of the outer end portion 27. The second rubber portion 32 is annular along the metal ring 21. The second rubber portion 32 contacts the second step surface 55 over the entire circumference. The rubber portion 22 is the same in the first embodiment as in the second embodiment, except for the shape of the third rubber 33.

[0047] In the second embodiment, fitting portion 28 is also provided discontinuously in the circumferential direction, and fitting portion 28 has, on its radially inner side, exposed surface 43 that is not covered by rubber portion 22. Fitting portion 28 has, on a first axial side, end surface 28a that contacts first step surface 53. 7, the metal ring 21 has a small plate piece portion 69 that extends radially outward from the radially outer end 26a of the annular portion 26 in the region where the cutout portion 42 is formed. The plate piece portion 69 is shorter than the connecting piece portion 41 (see FIG. 6). The plate piece portion 69 may be omitted.

[0048] [Regarding the ball bearing 10 of each of the above embodiments] As described above, ball bearing 10 in each of the above embodiments has inner ring 11, outer ring 12, multiple balls 13, first seal 16, and second seal 17. Outer ring 12 has first seal groove 18 for mounting first seal 16 on a first axial side. Outer ring 12 has second seal groove 19 for mounting second seal 17 on a second axial side.

[0049] 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 second seal groove 19 has a symmetrical shape to the first seal groove 18. The first seal 16 has a metal ring 21 and a rubber portion 22 that is integral with the metal ring 21. The second seal 17 has a symmetrical shape to the first seal 16.

[0050] 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. The outer end portion 27 has a fitting portion 28 that extends from the second axial side to the first axial side, and a missing portion 29 that is partially provided in the circumferential direction. The fitting portion 28 is plastically deformed and crimped to fit into the first seal groove 18.

[0051] 2 and 3, the outer end portion 27 has an annular connecting portion 30 that extends radially outward from the annular portion 26 and connects to the fitting portion 28. The connecting portion 30 has a through hole 40 as the missing portion 29. 6 and 7, the outer end 27 has connecting piece portions 41 that are spaced apart in the circumferential direction, extend radially outward from the annular portion 26, and connect to the fitting portion 28. The outer end 27 has a cutout portion 42 as a missing portion 29 that is provided between two connecting piece portions 41 that are adjacent to each other in the circumferential direction.

[0052] The rubber portion 22 has a first rubber portion 31 located on a first axial side of the outer end portion 27, a second rubber portion 32 located on a second axial side of the outer end portion 27 and in contact with the second step surface 55 over the entire circumference, and a third rubber portion 33 located in the missing portion 29. In the case of the embodiment shown in FIG. 2 and FIG. 3, the third rubber portion 33 is provided in the through hole 40 and connects the first rubber portion 31 and the second rubber portion 32 together. In the case of the embodiment shown in FIGS. 6 and 7, the third rubber portion 33 connects the first rubber portion 31 and the second rubber portion 32 across the cutout portion 42.

[0053] In each of the above embodiments (see FIGS. 2 and 6), the fitting portion 28 of the metal ring 21 is located radially outward of the inner protrusion 52, and is located within the axial range of the first step surface 53 and the outer recessed portion 54. With this configuration, even if the first seal 16 attempts to fall off toward the first axial side, the falling off is prevented by preventing the fitting portion 28 from moving toward the first step surface 53.

[0054] The second rubber portion 32 contacts the entire periphery of the second step surface 55 of the first seal groove 18. This makes it possible to prevent the lubricating oil in the bearing internal space from leaking out to the outside through the gap between the first seal 16 and the outer ring 12. The outer end 27 of the metal ring 21 has a missing portion 29 (a through hole 40 or a cutout portion 42), and the third rubber portion 33 is located in the missing portion 29 and connects the first rubber portion 31 and the second rubber portion 32. Therefore, the bonding strength between the metal ring 21 and the rubber portion 22 is high.

[0055] In each of the above embodiments, the fitting portion 28 has an end face 28a on the first axial side that contacts the first step surface 53. With this configuration, when the first seal 16 attempts to fall off toward the first axial side, the end face 28a of the fitting portion 28 comes into contact with the first step surface 53 of the first seal groove 18, preventing the first seal 16 from falling off.

[0056] In each of the above embodiments, the first seal 16 is not in contact with the inner ring 11. For this reason, the infiltration of lubricating oil into the internal space of the bearing is permitted between the first seal 16 and the inner ring 11. The first seal 16 prevents the lubricating oil that has infiltrated into the internal space of the bearing from flowing out to the first axial side. The second seal 17 is not in contact with the inner ring 11. For this reason, the lubricating oil is permitted to infiltrate into the internal space of the bearing from between the second seal 17 and the inner ring 11. The second seal 17 prevents the lubricating oil that has infiltrated into the internal space of the bearing from flowing out to the second axial side. As described above, even if the amount of lubricating oil is small in a device employing ball bearing 10, the lubricating oil is retained in the bearing internal space of ball bearing 10. This maintains the lubricating performance of ball bearing 10. Furthermore, even if the lubricating oil is present in the bearing internal space and ball bearing 10 rotates at high speed, first seal 16 is prevented from falling off first seal groove 18, and second seal 17 is prevented from falling off second seal groove 19.

[0057] 〔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]

[0058] 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 Fitting part 28a End face 29 Missing Part 30 Connecting part 31 First Rubber Section 32 Second rubber section 33 Third Rubber Section 40 through hole 41 Connecting piece 42 Cutout 43 Exposed surface 51 Side 52 Inner protrusion 53 First stage surface 54 Outer recess 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 integral with the metal ring, 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 is a fitting portion extending from a second axial side to a first axial side and fitting into the first seal groove; A missing portion partially provided in the circumferential direction; having The rubber portion is a first rubber portion located on a first axial side of the outer end portion and having an annular shape along the metal ring; a second rubber portion located on a second axial side of the outer end portion and in contact with the second step surface over an entire circumference thereof; a third rubber portion located in the missing portion and connecting the first rubber portion and the second rubber portion; having The fitting portion is located radially outward from the inner protruding portion and within an axial range of the first step surface and the outer recessed portion. ball bearings.

2. The fitting portion has an end surface on a first axial side that contacts the first step surface.

2. A ball bearing according to claim 1.

3. The first seal is not in contact with the inner ring.

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

4. The outer end portion has an annular connecting portion that extends radially outward from the annular portion and is connected to the fitting portion, The connecting portion has a through hole as the missing portion, The third rubber portion is provided in the through hole and connects the first rubber portion and the second rubber portion.

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

5. The outer end portion has connecting piece portions that are provided at intervals in the circumferential direction, extend radially outward from the annular portion, and are connected to the fitting portion, The outer end portion has a notch portion provided between two of the connecting piece portions adjacent to each other in the circumferential direction as the missing portion, The third rubber portion connects the first rubber portion and the second rubber portion across the cutout portion.

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

6. 3. The ball bearing according to claim 1, wherein the fitting portion has, on a radially inner side thereof, an exposed surface that is not covered by the rubber portion.

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