Rolling bearings and devices

Abstract

To suppress breakage of an O-ring.SOLUTION: A rolling bearing includes an outer ring, an inner ring, a rolling element rotatably arranged between the outer ring and the inner ring, and an O-ring made of an elastic body and fitted to a peripheral groove provided on an outer peripheral surface of the outer ring. A first bottom surface is provided in an axial center of the peripheral groove, and a second bottom surface extending in a circumferential direction and having a diameter smaller than that of the first bottom surface is provided in an axial end of the first bottom surface.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a rolling bearing. and equipment Regarding. [Background technology]

[0002] 2. Description of the Related Art In order to ensure airtightness and absorb vibrations in a device in which a rolling bearing is mounted in a housing, a technique is known in which an O-ring made of an elastic material is mounted on the outer peripheral surface of the raceway of the rolling bearing. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5505549 [Patent Document 2] JP 2015-72034 A Summary of the Invention [Problem to be solved by the invention]

[0004] To improve the sealing performance and vibration absorption of the O-ring, it is desirable to make the repulsive force of the O-ring against the housing strong, but this makes the O-ring more susceptible to damage or breakage during the installation process of mounting the rolling bearing to the housing.

[0005] On the one hand, a rolling bearing that can suppress damage to O-rings and equipment The purpose is to provide. [Means for solving the problem]

[0006] In one embodiment, the rolling bearing comprises an outer ring, an inner ring, rolling elements arranged between the outer ring and the inner ring so as to be able to roll, and an O-ring made of an elastic body fitted into a circumferential groove provided on the outer peripheral surface of the outer ring. A first bottom surface is provided at the axial center of the circumferential groove, and a second bottom surface is provided at an axial end of the first bottom surface, extending in the circumferential direction and having a smaller diameter than the first bottom surface. The first bottom surface and the second bottom surface are not continuous with each other, and a corner is formed near a contact point between the first bottom surface and the second bottom surface.

[0007] According to one embodiment, damage to the O-ring can be suppressed. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a side cross-sectional view showing an example of a rolling bearing according to an embodiment. [Diagram 2] FIG. 2 is an enlarged cross-sectional view showing an example of a circumferential groove of a rolling bearing in an embodiment. [Diagram 3] FIG. 3 is an enlarged cross-sectional view showing an example of a circumferential groove in which an O-ring is disposed in the embodiment. [Figure 4A] FIG. 4A is an enlarged cross-sectional view showing an example of a process for mounting the rolling bearing to a housing in the embodiment. [Figure 4B] FIG. 4B is an enlarged cross-sectional view showing an example of a process of mounting the rolling bearing to a housing in the embodiment. [Diagram 5] FIG. 5 is an enlarged perspective view showing an example of a rolling bearing attached to a housing in an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The rolling bearing disclosed in the present application is as follows: and equipment The embodiment of the present invention will be described in detail with reference to the drawings. The dimensional relationship of each element in the drawings, the ratio of each element, etc. may differ from reality. The drawings may also include parts with different dimensional relationships and ratios. In order to make the description easier to understand, each drawing may show a coordinate system in which the axial direction of a shaft 80, which will be described later, extends. In addition, the circumferential direction and radial direction in the following description refer to the circumferential direction and radial direction of the rolling bearing 20, which will be described later.

[0010] [Embodiment] First, the rolling bearing in the embodiment will be described. Fig. 1 is a side cross-sectional view showing an example of a rolling bearing in the embodiment. Fig. 1 shows a cross section of an annular rolling bearing 20 cut at the diameter of the rolling bearing 20. That is, the configuration shown in the upper part of Fig. 1 and the configuration shown in the lower part show, with some exceptions, the upper part and the lower part of an annular member.

[0011] 1, the rolling bearing 20 in this embodiment includes an outer ring 30, an inner ring 40 arranged on the inner periphery of the outer ring 30, a plurality of spherical rolling elements 23, a retainer 24, and a sealant 25. Grease G is enclosed within the space sealed by the sealant 25. Note that the sealant 25 and the retainer 24 are not essential. A full spherical bearing not including the retainer 24 is also within the technical scope of the present invention.

[0012] The multiple rolling elements 23 are, for example, metallic spheres, and are provided to be able to roll between the raceway groove 32 of the outer ring 30 and the raceway groove 42 of the inner ring 40. The multiple rolling elements 23 are, for example, disposed at equal intervals in the circumferential direction. In Fig. 1, only some of the multiple rolling elements 23, namely, rolling elements 23a and 23n, are shown.

[0013] The cage 24 has pockets that rotatably hold the rolling elements 23. The grease G is disposed in a bearing space surrounded by the outer ring 30 and the inner ring 40. The grease G is sealed on the inner peripheral surface side of the outer ring 30 on both axial sides and the other axial sides of the bearing space, sandwiching the multiple rolling elements 23 therebetween. The volume of the sealed grease G is, for example, 3 to 60% of the volume of the bearing space.

[0014] The rolling bearing 20 in the embodiment rotatably supports a shaft 80. The rolling bearing 20 is inserted and mounted in a housing 70 of a fan motor, a pump, a valve opening and closing mechanism, a transmission, or the like. At that time, an O-ring 60 made of an elastic body such as rubber is disposed between the rolling bearing 20 and the housing 70 in the radial direction in order to ensure airtightness and absorb vibrations. In the embodiment, the O-ring 60 is disposed by being fitted into a circumferential groove 50 formed on the outer peripheral surface 31 of the outer ring 30 of the rolling bearing 20.

[0015] The circumferential groove 50 is formed in the circumferential direction along the outer peripheral surface 31 of the outer ring 30 of the rolling bearing 20. For example, a plurality of circumferential grooves 50 are formed at equal intervals in the axial direction. In this case, the O-ring 60 may be fitted into only one of the plurality of circumferential grooves 50, or may be fitted into both of the circumferential grooves 50. Also, only one circumferential groove 50 may be provided on the outer peripheral surface 31. As shown in FIG. 1, the rolling bearing 20 in the embodiment includes two circumferential grooves 50a and 50b formed at a distance from each other in the axial direction. In the following description, the circumferential grooves 50a and 50b may be simply referred to as the circumferential groove 50 when there is no need to distinguish between them.

[0016] Known rubbers such as NBR, hydrogenated NBR, EPDM, acrylic rubber, and fluororubber are used for the elastic body forming the O-ring 60. Note that it is desirable for the elastic body forming the O-ring 60 to have heat resistance, oil resistance, cold resistance, and chemical resistance depending on the application.

[0017] In the embodiment, the O-rings 60 are disposed in the circumferential grooves 50a and 50b, respectively. That is, in the embodiment, two O-rings 60a and 60b are disposed for the rolling bearing 20. In the following description, when there is no need to distinguish between the O-rings 60a and 60b, they may be simply referred to as O-ring 60.

[0018] As shown in Figures 1 and 2, the circumferential groove 50 has a plurality of bottom surfaces with different radial depths. Figure 2 is an enlarged cross-sectional view showing an example of a circumferential groove of a rolling bearing in an embodiment. Figure 2 is an enlarged view of a portion shown in frame F1 in Figure 1.

[0019] 2, the circumferential groove 50 includes a first bottom surface 51, two second bottom surfaces 52a and 52b, and two side walls 55a and 55b. In the following description, when the second bottom surfaces 52a and 52b are not differentiated from each other, they may be simply referred to as the second bottom surface 52, and when the side walls 55a and 55b are not differentiated from each other, they may be simply referred to as the side walls 55.

[0020] The side wall 55 is formed substantially parallel to the radial direction. That is, in the embodiment, the circumferential groove 50 is formed with neither a protruding portion nor a cutout portion in the axial direction.

[0021] The first bottom surface 51 of the circumferential groove 50 extends in the circumferential direction of the rolling bearing 20. In the embodiment, the first bottom surface 51 is formed so that the distance from the housing 70 and the distance from the shaft 80 in the radial direction are substantially constant. In this case, the cross section of the first bottom surface 51 in the axial direction has a linear shape substantially parallel to the axial direction, as shown in FIG.

[0022] The second bottom surfaces 52a and 52b extend in the circumferential direction like the first bottom surface 51, and are formed adjacent to the first bottom surface 51 in the axial direction. That is, the first bottom surface 51 is provided in the center of the circumferential groove 50 in the axial direction, and the pair of second bottom surfaces 52a and 52b are provided on both ends of the first bottom surface 51 in the axial direction. For example, the second bottom surface 52a contacts the first bottom surface 51 at a contact point 59 shown in FIG. 2.

[0023] The second bottom surface 52 is formed radially inward by a size D1 from the first bottom surface 51. That is, the size of the second bottom surface 52 in the radial direction is smaller than the size of the first bottom surface 51 in the radial direction.

[0024] Also, the axially outer end of the second bottom surface 52 is located axially inward of the side wall 55. For example, as shown in Fig. 2, the left end of the second bottom surface 52a in the figure is located to the right of the side wall 55a in the figure, and the right end of the second bottom surface 52b in the figure is located to the left of the side wall 55b in the figure.

[0025] In the embodiment, the second bottom surface 52 may be formed, for example, so that the distance to the housing 70 and the distance to the shaft 80 in the radial direction change. For example, as shown in FIG. 2, the outer portion of the second bottom surface 52, i.e., the portion in contact with the side wall 55 and the portion in contact with the first bottom surface 51, is larger in the radial direction than the central portion of the second bottom surface 52.

[0026] In the embodiment, the radial size of the second bottom surface 52 changes continuously in the axial direction. That is, the cross section of the second bottom surface 52 in the axial direction is arc-shaped, as shown in Fig. 2. On the other hand, in the embodiment, the first bottom surface 51 and the second bottom surface 52 are not continuous. For example, as shown in Fig. 2, the portion of the second bottom surface 52 that contacts the first bottom surface 51 does not have a portion that is approximately parallel to the axial direction.

[0027] In the embodiment, the first bottom surface 51 is formed so as to occupy a certain portion of the circumferential groove 50 in the axial direction. The circumferential groove 50 in the embodiment is formed so that, for example, the length L1 in the axial direction of the first bottom surface 51 is 40% or more of the length L0 in the axial direction of the circumferential groove 50, i.e., the distance between the side walls 55a and 55b.

[0028] In the circumferential groove 50 shown in FIG. 2, an O-ring 60 is disposed as shown in FIG. 3. FIG. 3 is an enlarged cross-sectional view showing an example of a circumferential groove in which an O-ring is disposed in an embodiment. As shown in FIG. 3, a distance H1 from a first bottom surface 51 of the circumferential groove 50 to an outer peripheral surface 31 of an outer ring 30 of a rolling bearing 20 is smaller than a diameter R1 of the O-ring 60. On the other hand, a length L0 of the circumferential groove 50 in the axial direction is larger than the diameter R1 of the O-ring 60. In this case, the O-ring 60 disposed in the circumferential groove 50 protrudes radially outward from the circumferential groove 50 as shown in FIG. 3, but does not contact at least one of the side walls 55a and 55b.

[0029] The rolling bearing 20 in the embodiment is inserted into the housing 70 as shown in Figures 4A to 5 with the O-ring 60 disposed in the circumferential groove 50 as shown in Figure 3. Figures 4A and 4B are enlarged cross-sectional views showing an example of a process for mounting the rolling bearing to the housing in the embodiment. Figure 5 is an enlarged perspective view showing an example of the rolling bearing mounted to the housing in the embodiment. In Figures 4A to 5, the color intensity of the O-ring 60 that has been pressed and deformed indicates the strength of the stress applied to the O-ring 60.

[0030] 4A and 4B, the housing 70 moves relative to the rolling bearing 20 in the direction indicated by the arrow in FIG. 4A, that is, from the direction where the side wall 55b and the second bottom surface 52b are located to the direction where the side wall 55a and the second bottom surface 52a are located. In this case, as shown in FIG. 4A, a part 61 (first part 61) of the O-ring 60 that protrudes radially outward from the circumferential groove 50 in FIG. 3 is pressed to the left side in the figure by the housing 70 and deformed. At this time, the O-ring 60 that was in contact with the side wall 55b moves to the side wall 55a, and stress is applied to the deformed O-ring 60, centered on the first part 61, as shown in FIG. 4A.

[0031] Then, as the housing 70 moves further relative to the rolling bearing 20, another part 62 (second part 62) of the O-ring 60 that has been pressed and deformed moves to a position close to one of the second bottom surfaces 52a (the second bottom surface located at a position approaching the housing 70 later) of the circumferential groove 50. Also, another part 63 (third part 63) of the O-ring 60 moves to a position close to the other of the second bottom surfaces 52b (the second bottom surface located at a position approaching the housing 70 earlier) of the circumferential groove 50. As a result, the O-ring 60 is accommodated in the circumferential groove 50 without protruding radially outwardly beyond the outer circumferential surface 31 of the outer ring 30 of the rolling bearing 20. In the embodiment, the second part 62 is larger than the third part 63.

[0032] When the outer ring 30 with the O-ring 60 disposed therein is fitted into the housing 70, a large stress is applied to the first portion 61. However, in the embodiment, the stress applied to the O-ring 60 is not concentrated only on the first portion 61, but is also distributed to other portions. For example, as shown in FIG. 4B, the stress applied to the first portion 61 is smaller than the stress applied to a portion 69 (fourth portion 69) close to the first bottom surface 51 of the circumferential groove 50. In this case, the O-ring 60 is prevented from breaking during the installation process.

[0033] As shown in FIG. 5, in a state where the outer ring 30 is fitted into the housing 70 (a state where the rolling bearing 20 is inserted into the housing 70), the O-ring 60 is pressed and deformed, so that the second portion 62 contacts the second bottom surface 52a on one side in the radial direction, and the third portion 63 contacts the second bottom surface 52b on the other side in the radial direction. Furthermore, the fourth portion 69 of the O-ring 60 contacts the first bottom surface 51 of the circumferential groove 50 in the radial direction. That is, a part of the O-ring 60 protrudes radially inward from the first bottom surface 51 on both sides of the first bottom surface 51 in the axial direction, so that the O-ring 60 has a substantially C-shape as shown in FIG. 5. It is not necessary that the second portion 62 and the third portion 63 contact the second bottom surface 52a and the second bottom surface 52b, respectively. Moreover, it is preferable that the fourth portion 69 of the O-ring 60 contacts the first bottom surface 51 of the circumferential groove 50 over the entire axial direction of the first bottom surface 51. For example, it is preferable that the deformed O-ring 60 contacts not only the contact point 59 between the first bottom surface 51 and the second bottom surface 52a, but also the contact point between the first bottom surface 51 and the second bottom surface 52b.

[0034] 5, a larger stress is applied to the fourth portion 69 in contact with the first bottom surface 51 from the first bottom surface 51. In particular, as shown in FIG. 2, the stress is larger near the contact point 59 between the first bottom surface 51 and the second bottom surface 52a of the circumferential groove 50, as the corner abuts against the O-ring 60. This stress becomes a repulsive force against the housing 70 as the O-ring 60, whose cross section has been deformed into a substantially C-shape, tries to return to its O-shape cross section. This allows the O-ring 60 to exert a sufficient repulsive force against the housing 70.

[0035] As described above, the rolling bearing 20 in the embodiment includes the outer ring 30, the inner ring 40, the rolling element 23 arranged to be rollable between the outer ring 30 and the inner ring 40, and the O-ring 60 made of an elastic body fitted into the circumferential groove 50 provided on the outer peripheral surface 31 of the outer ring 30. A first bottom surface 51 is provided at the axial center of the circumferential groove 50, and second bottom surfaces 52a and 52b extending in the circumferential direction and having a smaller diameter than the first bottom surface are provided at the axial ends of the first bottom surface 51. With this configuration, breakage of the O-ring 60 is suppressed, and the repulsive force of the O-ring 60 against the housing 70 can also be ensured.

[0036] Moreover, the length L1 in the axial direction of the first bottom surface 51 is 40% or more of the length L0 in the axial direction of the entire circumferential groove 50. Furthermore, the first bottom surface 51 is formed so that the distance from the housing 70 in the radial direction is approximately constant. With this configuration, a sufficient contact area is ensured between the first bottom surface 51 and the O-ring 60 in the radial direction, so that the stress applied to the O-ring 60 in the radial direction is large. Note that it is preferable that the fourth portion 69 of the O-ring 60 contacts the first bottom surface 51 of the circumferential groove 50 over the entire axial direction of the first bottom surface 51.

[0037] In addition, the first bottom surface 51 and the second bottom surfaces 52a and 52b are not formed to be continuous in the axial direction. With this configuration, the stress applied to the O-ring 60 is prevented from escaping in the axial direction, so that the repulsive force against the housing 70 is ensured.

[0038] [Variations] Although the configuration in the embodiment has been described above, the embodiment is not limited thereto. For example, in the embodiment, the second bottom surfaces 52a and 52b are formed to be symmetrical in the axial direction, for example, but the embodiment is not limited thereto. For example, when the insertion direction into the housing 70 is constant, the two second bottom surfaces 52a, 52b may be asymmetrical in the axial direction, or a configuration in which only one second bottom surface is formed may be used. As described in the embodiment, for example, when the housing 70 moves only in the direction indicated by the arrow in FIG. 4A, even if the third portion 63 is not formed, the breakage of the O-ring 60 is suppressed and the repulsive force of the O-ring 60 against the housing 70 can be secured. In this case, the circumferential groove 50 may be configured not to have the second bottom surface 52b.

[0039] Although the present invention has been described above based on the embodiment and each modification, it goes without saying that the present invention is not limited to the embodiment and each modification, and various modifications are possible within the scope of the gist of the present invention. Such modifications that do not depart from the scope of the gist are also included in the technical scope of the present invention, and this will be clear to those skilled in the art from the description of the claims. [Explanation of symbols]

[0040] 20 rolling bearing, 23 rolling element, 30 outer ring, 31 outer peripheral surface, 40 inner ring, 50 circumferential groove, 51 first bottom surface, 52a, 52b second bottom surface, 55a, 55b side wall, 60 O-ring, 70 housing, 80 shaft

Claims

1. An outer ring and an inner ring; a rolling element disposed between the outer ring and the inner ring so as to be capable of rolling; an O-ring made of an elastic body that is fitted into a circumferential groove provided on an outer peripheral surface of the outer ring; Equipped with A first bottom surface is provided at the axial center of the circumferential groove, A second bottom surface is provided at an axial end of the first bottom surface, the second bottom surface extending in a circumferential direction and having a smaller diameter than the first bottom surface, The first bottom surface and the second bottom surface are not continuous, A corner portion is formed near a contact point between the first bottom surface and the second bottom surface. Rolling bearing.

2. 2. The rolling bearing according to claim 1, wherein an axial length of the first bottom surface is 40% or more of an axial length of the circumferential groove.

3. The rolling bearing according to claim 1 or 2, wherein the second bottom surface is provided on both axial ends of the first bottom surface.

4. The rolling bearing according to claim 1 , wherein the second bottom surface is formed axially inwardly of a side wall of the circumferential groove.

5. A rolling bearing according to any one of claims 1 to 4, a housing into which the outer ring is fitted by inserting the rolling bearing; Equipped with After the rolling bearing is inserted into the housing, a portion of the O-ring elastically deforms toward the second bottom surface into a C-shaped cross section. Device.

6. The second bottom surface is provided at both axial ends of the first bottom surface, After the rolling bearing is inserted into the housing, a portion of the O-ring contacts the first bottom surface, and another portion of the O-ring contacts one of the pair of second bottom surfaces.

6. The apparatus of claim 5.

7. An apparatus as described in claim 5 or 6, wherein after the rolling bearing is inserted into the housing, a portion of the O-ring contacts the first bottom surface along the entire axial direction of the first bottom surface.

8. An apparatus described in any one of claims 5 to 7, wherein the first bottom surface is formed so that the radial distance from the housing is approximately constant.

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