WO2023095639A1 - Rolling bearing - Google Patents

Abstract

Provided is a rolling bearing in which, even when a retainer is elastically deformed by a centrifugal force, interference between rolling elements and the retainer can be suppressed. A rolling bearing 1 comprises: an outer ring 2 having an outer-ring race surface 2a on the inner circumference thereof; an inner ring 3 having an inner-ring race surface 3a on the outer circumference thereof; a plurality of balls 4 interposed between the outer-ring race surface 2a and the inner-ring race surface 3a; and a retainer 5 having a plurality of pockets 8 that hold the balls 4. The retainer 5 comprises: an annular base part 6; and multiple pairs of claws 7 that are disposed at a fixed interval at axial-direction end faces of the base part 6 in the circumferential direction and that extend in the axial direction. The pockets 8 of the retainer 5 are formed from the base part 6 and the multiple pairs of claws 7. The multiple pairs of claws 7 are each inclined toward the radially inner side relative to the axis and each have a concavely curved surface 8a on which the ball 4 is retained. The pitch circle Pp of the pockets is positioned on the radially inner side relative to the pitch circle Pb of the balls.

Description

rolling bearing

The present invention relates to rolling bearings.

Rolling bearings such as deep groove ball bearings, angular contact ball bearings, and roller bearings are widely used as rolling bearings for supporting wheels, rotating shafts of machinery, etc. A rolling bearing mainly includes an outer ring, an inner ring positioned inside the outer ring, a plurality of rolling elements, and a retainer. In the rolling bearing, a plurality of rolling elements are housed between raceway surfaces formed on the inner peripheral surface of the outer ring and the outer peripheral surface of the inner ring. Further, the rolling bearing is rotatably held by a cage that holds a plurality of rolling elements at a constant pitch. Grease, which is a lubricant, may be sealed inside the rolling bearing to reduce friction and wear between the outer ring, inner ring, rolling elements and cage. Some cages for such rolling bearings have, at their radial ends, cylindrical surface portions that facilitate taking in grease into pocket portions that hold rolling elements. For example, it is like patent document 1.

A retainer for a rolling bearing disclosed in Patent Document 1 includes a spherical portion having a radius of curvature slightly larger than the radius of curvature of a rolling contact surface on the inner surface of a pocket formed by a pair of elastic pieces and an annular member, and the spherical surface. and a cylindrical surface portion continuous from the edge of the portion. The pocket covers part of the circumferential side surface, part of the radially outer side surface, and part of the radially inner side surface of the rolling element with the spherical surface portion. Since the retainer increases the radial opening area of the pocket due to the cylindrical surface portion, it is possible to smoothly take the lubricant into the pocket. As a result, the rolling bearing described in Patent Document 1 promotes smooth rotation between the rolling elements and the cage, and reduces collision noise between the rolling elements and the cage.

JP-A-11-125256

In the rolling bearing described in Patent Document 1, the retainer rotates together with the rolling elements as the inner ring or outer ring rotates. A centrifugal force corresponding to the rotation speed is applied radially outward to the retainer. In the retainer, a pair of elastic pieces forming a part of the pocket is elastically deformed radially outward by centrifugal force. Of the spherical portions of the pair of elastic pieces, the portion covering the radially inner side of the rolling element moves toward the rolling element due to the action of centrifugal force as the rotational speed increases. Therefore, in the rolling bearing, when the outer ring or inner ring exceeds a predetermined rotational speed, the radially inner portions of the pair of elastic pieces and the rolling elements come into contact with each other. As a result, there is a possibility that the rolling bearing described in Patent Literature 1 may cause wear and heat generation of the retainer during high-speed rotation.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a rolling bearing capable of suppressing interference between the rolling elements and the cage even if the cage is elastically deformed by centrifugal force. .

A rolling bearing according to an embodiment of the present invention comprises an outer ring having an outer ring raceway surface on its inner peripheral surface; an inner ring positioned inside the outer ring and having an inner ring raceway surface on its outer peripheral surface; A plurality of rolling elements interposed between the inner ring raceway surface and a retainer having a plurality of pocket portions for holding the rolling elements, wherein the retainer includes an annular base portion and an axial end surface of the base portion. The rolling bearing is configured by a plurality of pairs of claw portions positioned at regular intervals in the circumferential direction and extending in the axial direction. The plurality of pocket portions of the retainer are composed of the base portion and the plurality of pairs of claw portions, and the plurality of pairs of claw portions are inclined radially inward with respect to the axis, and the rolling elements It has a curved surface that holds the The pocket portion pitch circle diameter passing through the center of curvature of the curved surface of each of the plurality of pocket portions is smaller than the rolling element pitch circle diameter passing through the center of the plurality of rolling elements.

In the above-described configuration, the radial clearance between the radially inner end of the pocket and the plurality of rolling elements is defined by the pitch circle of the pocket and the plurality of rolling elements, because the plurality of claws are not inclined radially inward. Larger than when the rolling element pitch circles are coincident. In the retainer, when the claw portions are elastically deformed radially outward due to the centrifugal force generated by the circumferential rotation, the radially inner ends of the pocket portions approach the rolling elements. However, the radially inner ends of the plurality of claws do not contact the rolling elements until the pocket pitch circle diameter becomes larger than the rolling element pitch circle diameter due to radially outward elastic deformation. Thereby, even if centrifugal force causes elastic deformation of the cage, interference between the plurality of rolling elements and the cage can be suppressed.

From another point of view, the rolling bearing of the present invention preferably includes the following configurations. In the retainer, the thickness from the base end face, which does not have the claw portion, to the tip end face between the adjacent pocket portions, among both axial end faces of the base portion, is equal to It is larger than the thickness to the bottom surface and smaller than the length from the base end surface to the center of curvature of the curved surfaces of the plurality of pocket portions. The base thickness of the retainer of the rolling bearing is thicker in the axial direction than the thickness at the bottom of the pocket portion, and the lower and upper limit values of the thickness of the base portion are set so that it does not become thicker than the approximate center of the axial length of the pawl portion. is set, the rigidity of the base is sufficient to support the plurality of claws while suppressing the weight. Therefore, in the retainer, the amount of elastic deformation of the plurality of claw portions due to centrifugal force is suppressed. Thereby, even if centrifugal force causes elastic deformation of the cage, interference between the plurality of rolling elements and the cage can be suppressed.

From another point of view, the rolling bearing of the present invention preferably includes the following configurations. In the retainer, curved surfaces of the plurality of pocket portions follow an elliptical surface having a major axis in a radial direction of the retainer. With this configuration, the retainer of the rolling bearing is configured such that the radial ends of the plurality of pocket portions are radially separated from the plurality of rolling elements. Therefore, the radial gaps between the radially inner ends of the plurality of pocket portions and the plurality of rolling elements are larger than when the plurality of pocket portions have curved surfaces along the rolling elements. Thereby, even if centrifugal force causes elastic deformation of the cage, interference between the plurality of rolling elements and the cage can be suppressed.

From another point of view, the rolling bearing of the present invention preferably includes the following configurations. When the retainer is not rotating in the circumferential direction, the radial direction of the retainer from the radially inner end of the plurality of pocket portions to the rolling elements held by the plurality of pocket portions. is larger than the radial gap in the retainer from the radially outer ends of the plurality of pocket portions to the rolling elements held by the plurality of pocket portions. With this configuration, in the retainer of the rolling bearing, the radial gaps from the radially inner end portions of the plurality of pocket portions to the plurality of rolling elements are equal to the radially outer end portions of the pocket portions. to the plurality of rolling elements. Therefore, in the retainer, the radially inner ends of the plurality of pocket portions are displaced until the pocket portion pitch circle diameter becomes larger than the rolling element pitch circle diameter due to the radially outward elastic deformation of the plurality of claw portions. Do not contact multiple rolling elements. Thereby, even if centrifugal force causes elastic deformation of the cage, interference between the plurality of rolling elements and the cage can be suppressed.

From another point of view, the rolling bearing of the present invention preferably includes the following configurations. When the retainer is not rotating in the circumferential direction, the radially outer ends of the plurality of pocket portions and the rolling elements held by the plurality of pocket portions are in contact with each other. With this configuration, in the retainer of the rolling bearing, the radially outer ends of the curved surfaces of the plurality of pocket portions are in contact with the plurality of rolling elements. On the other hand, the radially inner ends of the curved surfaces of the plurality of pocket portions are separated from the rolling elements. As a result, even if the plurality of claw portions elastically deform radially inward due to centrifugal force, interference between the plurality of rolling elements and the retainer can be suppressed.

From another point of view, the rolling bearing of the present invention preferably includes the following configurations. The retainer has chamfered portions connecting the curved surfaces of the plurality of pocket portions and the inner peripheral surface of the retainer. By configuring in this way, the retainer of the rolling bearing has an increased radially inner opening area in the plurality of pocket portions. Therefore, in the retainer, the gaps between the radially inner ends of the plurality of pocket portions and the plurality of rolling elements are enlarged. Thereby, even if centrifugal force causes elastic deformation of the cage, interference between the plurality of rolling elements and the cage can be suppressed.

From another point of view, the rolling bearing of the present invention preferably includes the following configurations. In the retainer, the radius of curvature of the curved surface of the pocket portion is 1.01 times or more and 1.10 times or less the radius of the rolling element. By configuring in this way, in the retainer of the rolling bearing, the radius of curvature of the plurality of pocket portions is larger than the radius of curvature of the plurality of rolling elements. Therefore, in the retainer, gaps are always formed between the curved surfaces of the plurality of pocket portions and the plurality of rolling elements. Thereby, even if centrifugal force causes elastic deformation of the cage, interference between the plurality of rolling elements and the cage can be suppressed.

From another point of view, the rolling bearing of the present invention preferably includes the following configurations. In the retainer, the pocket portion pitch diameter is between 90 percent and 99.5 percent of the rolling element pitch diameter. With this configuration, the retainer of the rolling bearing has an upper limit value and a lower limit value of the pocket portion pitch circle diameter with respect to the rolling element pitch circle diameter. Therefore, in the retainer, gaps of appropriate size are configured between the curved surfaces of the plurality of pocket portions and the plurality of rolling elements. Thereby, even if centrifugal force causes elastic deformation of the cage, interference between the plurality of rolling elements and the cage can be suppressed.

From another point of view, the rolling bearing of the present invention preferably includes the following configurations. The retainer is made of a resin material, and the resin material has a glass transition temperature of 120° C. or higher. With this configuration, the retainer of the rolling bearing is made of a resin material having a glass transition temperature of 120° C. or higher. Thereby, the moldability and heat resistance of the retainer can be improved.

From another point of view, the rolling bearing of the present invention preferably includes the following configurations. The retainer has a base at which welds are formed during injection molding. With this configuration, the retainer of the rolling bearing has the weld portion formed during injection molding located at the base portion, so that it is possible to suppress the decrease in strength due to the weld portion. Thereby, even if centrifugal force causes elastic deformation of the cage, interference between the plurality of rolling elements and the cage can be suppressed.

According to one embodiment of the present invention, even if centrifugal force causes elastic deformation of the cage, interference between the plurality of rolling elements and the cage can be suppressed.

FIG. 1 is an axial cross-sectional view showing the configuration of a rolling bearing according to Embodiment 1 of the present invention. FIG. 2 is a perspective view of a retainer that retains balls in the rolling bearing according to Embodiment 1 of the present invention. 3 is a plan view of a retainer that retains balls in the rolling bearing according to Embodiment 1 of the present invention. FIG. 4 is a side view of a retainer in the rolling bearing according to Embodiment 1 of the present invention. FIG. FIG. 5 is an enlarged plan view of a retainer that retains balls in the rolling bearing according to Embodiment 1 of the present invention. FIG. 6 is an enlarged axial cross-sectional view of a retainer that retains balls in the rolling bearing according to Embodiment 1 of the present invention. FIG. 7 is an enlarged plan view when centrifugal force acts on a retainer that retains balls in the rolling bearing according to Embodiment 1 of the present invention. FIG. 8 is an enlarged axial cross-sectional view when a centrifugal force acts on a retainer that retains balls in the rolling bearing according to Embodiment 1 of the present invention. FIG. 9 is an enlarged plan view of a retainer that retains balls in a rolling bearing according to Embodiment 2 of the present invention. FIG. 10 is an enlarged plan view of a retainer that retains balls in a rolling bearing according to Embodiment 3 of the present invention.

(Embodiment 1)
A rolling bearing 1, which is an embodiment of a rolling bearing according to the present invention, will be described below with reference to FIGS. 1 to 3. FIG. FIG. 1 is an axial cross-sectional view showing the configuration of a rolling bearing 1 according to Embodiment 1 of the present invention. FIG. 2 is a perspective view of retainer 5 that retains balls 4 in rolling bearing 1 . FIG. 3 is a plan view of the retainer 5 that holds the balls 4 in the rolling bearing 1. FIG.

　As shown in Fig. 1, the rolling bearing 1 is a deep groove ball bearing. A rolling bearing 1 has an outer ring 2, an inner ring 3, a retainer 5, and balls 4 which are a plurality of rolling elements. Here, the axial direction indicates the direction along the rotation axis of the rolling bearing 1 or the axial direction of the base portion 6 of the retainer 5 . A radial direction represents a direction perpendicular to the axis of the rolling bearing 1 or the axis of the base 6 of the retainer 5 . Circumferential direction means a direction along the rotation direction of the rolling bearing 1 or the retainer 5 . The radially inner side represents the side closer to the axis in the radial direction than an arbitrary position. The radially outer side represents the side farther from the axis in the radial direction than an arbitrary position.

The outer ring 2 is a member that rotates relative to the inner ring 3. The outer ring 2 is a cylindrical member. The outer ring 2 is made of, for example, bearing steel such as high-carbon chromium bearing steel SUJ2, carburized steel, or the like. Further, the outer ring 2 is hardened by heat treatment to a hardness of about 58 to 62 HRC. The inner peripheral surface of the outer ring 2 has an annular outer ring raceway surface 2a in the circumferential direction on which a plurality of rolling elements roll. The outer ring raceway surface 2a is a groove that is recessed in an arc radially outward in an axial cross-sectional view.

The inner ring 3 is a member that rotates relative to the outer ring 2 . The inner ring 3 is a cylindrical member. The inner ring 3 is made of, for example, bearing steel such as high-carbon chromium bearing steel SUJ2, carburized steel, or the like. Further, the inner ring 3 is hardened by heat treatment to about 58 to 62 HRC. The outer peripheral surface of the inner ring 3 has an annular inner ring raceway surface 3a in the circumferential direction on which a plurality of rolling elements roll. The inner ring raceway surface 3a is a groove that is recessed in an arc radially inward in an axial cross-sectional view. The inner ring 3 is positioned radially inward of the outer ring 2 . The inner ring raceway surface 3 a of the inner ring 3 faces the outer ring raceway surface 2 a of the outer ring 2 .

The balls 4, which are rolling elements, are members that rotatably support the outer ring 2 and the inner ring 3 relative to each other. Ball 4 is a sphere. The ball 4 is composed of, for example, a steel ball made of high-carbon chromium bearing steel SUJ2, a stainless steel ball (SUS440C), a ceramic ball (Si3N4), or the like. The ball 4 is hardened to about 60 to 64 HRC by heat treatment depending on the material. A plurality of balls 4 are housed side by side in the circumferential direction between the outer ring raceway surface 2 a of the outer ring 2 and the inner ring raceway surface 3 a of the inner ring 3 . The plurality of balls 4 are configured to roll on the outer ring raceway surface 2a and the inner ring raceway surface 3a. Therefore, the plurality of balls 4 support the outer ring 2 with respect to the inner ring 3 so as to be rotatable in the circumferential direction. Also, the plurality of balls 4 support the inner ring 3 so as to be rotatable in the circumferential direction with respect to the outer ring 2 .

As shown in FIGS. 1 to 3, the cage 5 holds the balls 4. The retainer 5 is made of, for example, polyamide 46 (PA46), polyamide 66 (PA66), polyamide 9T (PA9T), polyetheretherketone (PEEK), polyphenylene, which are resin materials excellent in oil resistance, wear resistance, and lubricity. It is composed of sulfide (PPS) or the like. Further, as a reinforcing material, glass fiber (GF) or carbon fiber (CF) may be kneaded in the resin. The retainer 5 holds a plurality of balls 4 accommodated between the outer ring raceway surface 2a and the inner ring raceway surface 3a at regular intervals in the circumferential direction. Further, the retainer 5 is held between the outer ring 2 and the inner ring 3 so as to be rotatable in the circumferential direction with the axis as the rotation axis by the rolling of the plurality of balls 4 . At this time, the axis of the retainer 5 coincides with the axis of the outer ring 2 or the inner ring 3 . Grease, which is a lubricant, may be injected between the outer ring 2 and the inner ring 3 to reduce friction.

The rolling bearing 1 configured in this way is configured so that one of the outer ring 2 and the inner ring 3 is a fixed ring, and the other is a rotating ring, thereby exhibiting the function of a bearing. In the rolling bearing 1, when a torque is applied to at least one of the outer ring 2 and the inner ring 3, the balls 4 interposed between the outer ring raceway surface 2a and the inner ring raceway surface 3a roll to cause the outer ring 2 and the inner ring 3 to rotate. rotates relative to the axis. Together, the plurality of balls 4 and the retainer 5 rotate about the axis as the balls 4 move (so-called revolve) on the outer ring raceway surface 2a or the inner ring raceway surface 3a. At this time, the plurality of balls 4 rotate about a straight line passing through the center of the balls 4 that is perpendicular to a plane including the circumference passing through the contact points between the outer ring 2 and the balls 4 and the contact points between the balls 4 and the inner ring 3 as the axis of rotation. (so-called rotation).

Next, the retainer 5 will be described in detail using FIGS. 4 to 6. FIG. FIG. 4 is a side view of the retainer 5 in the rolling bearing 1. FIG. FIG. 5 is an enlarged plan view of retainer 5 that retains balls 4 in rolling bearing 1. As shown in FIG. FIG. 6 is an enlarged axial cross-sectional view of the cage 5 that holds the balls 4 in the rolling bearing 1. As shown in FIG.

As shown in FIG. 4, the retainer 5 is a crown-shaped retainer having a base portion 6, a pair of claw portions 7, and a pocket portion 8 composed of the base portion 6 and the pair of claw portions 7.

The base 6 supports the claw 7. The base 6 is an annular member. A plurality of pairs of claw portions 7 are positioned on a tip end face 6a which is one end face of both end faces of the base portion 6 in the axial direction. A pair of claw portions 7 extend in the axial direction from the tip surface 6a. The pair of claw portions 7 includes a claw portion 7a extending in one circumferential direction toward the tip and a claw portion 7b extending in the other circumferential direction toward the tip. The plurality of pairs of claw portions 7 are positioned at regular intervals along the circumferential direction. Therefore, the tip surface 6 a of the base portion 6 is formed between the pair of claw portions 7 and the pair of claw portions 7 .

The retainer 5 constitutes a plurality of pocket portions 8 that hold the balls 4 by a plurality of pairs of claw portions 7 and a base portion 6 between the plurality of pairs of claw portions 7 . Side surfaces of the plurality of pairs of claw portions 7 facing each other have concave curved surfaces 8 a that are spherical curved surfaces along the outer peripheral surface of the ball 4 . Similarly, the base portion 6 positioned between a plurality of adjacent pairs of claw portions 7 has a concave curved surface 8a recessed toward a base end surface 6b, which is the other end surface of both end surfaces in the axial direction. . The concave curved surface 8a of the pair of claw portions 7 and the concave curved surface 8a of the base portion 6 located between the pair of claw portions 7 are the same curvature center Cp (pocket center Cp) and curvature radius Dp of the surface of the spherical surface Vs. part (see FIG. 5). That is, the concave curved surface 8a of the pair of claw portions 7 and the concave curved surface 8a of the base portion 6 positioned between the pair of claw portions 7 are configured as one continuous concave curved surface.

In the retainer 5, the thickness t0 from the base end surface 6b of the base portion 6 to the tip end surface 6a between the adjacent pocket portions 8 is greater than the thickness t1 from the base end surface 6b to the bottom surfaces of the plurality of pocket portions 8. Further, the retainer 5 is shorter than the length t2 from the base end surface 6b to the pocket center Cp, which is the center of curvature Cp of the concave curved surface 8a. Therefore, the base 6 has a shape having rigidity capable of holding a plurality of balls 4 by limiting the upper limit of the thickness to the length t2, thereby suppressing the weight, and limiting the lower limit of the thickness to the thickness t1. have.

In this way, the plurality of pairs of claw portions 7 having the concave curved surfaces 8a and the base portion 6 between the plurality of pairs of claw portions 7 form a plurality of pocket portions 8 for holding the balls 4 . The concave curved surfaces 8 a of the pair of claws 7 form side surfaces of the pocket portion 8 . A concave curved surface 8 a of the base portion 6 constitutes the bottom surface of the pocket portion 8 . Each of the plurality of pocket portions 8 has a concave curved surface 8a that is closed in the axial direction by the pair of claw portions 7. As shown in FIG. The plurality of pocket portions 8 restrain axial movement with respect to the ball 4 by means of a pair of claw portions 7 .

As shown in FIGS. 5 and 6, the concave curved surface 8a of the pocket portion 8 is part of a spherical surface Vs which is a spherical surface with a predetermined curvature radius Dp located at a predetermined curvature center Cp. Therefore, in the retainer 5, the center of curvature of the spherical surface Vs is defined as the pocket center Cp, which is the center of the pocket portion 8, and the pocket portion pitch circle Pp passing through the pocket center Cp of the plurality of pocket portions 8 is determined. The pocket portion pitch circle Pp is a circle centered on the axis of the retainer 5 . The pocket portion 8 has a pocket center Cp positioned so that the pocket portion pitch circle Pp passes through substantially the radial center of the pair of claw portions 7 when viewed in the axial direction.

The concave curved surface 8a of the pocket portion 8, which is part of the spherical surface Vs, has a radius of curvature Dp larger than that of the ball 4. That is, the radius of curvature Dp of the concave curved surface 8a of the pocket portion 8 is larger than the radius of curvature Db of the outer surface of the ball 4 held in the pocket portion 8 . Specifically, the curvature radius Dp of the concave curved surface 8a of the pocket portion 8 is 1.01 times or more and 1.10 times or less the curvature radius Db that is the radius of the ball 4 . The retainer 5 in which the curvature radius Dp of the concave curved surface 8a is set in this manner suppresses an increase in the contact area between the concave curved surface 8a and the outer surface of the ball 4 due to elastic deformation, processing error, thermal deformation, etc. of the concave curved surface 8a. be able to. Therefore, a gap is formed between the concave curved surface 8 a of the pocket portion 8 and the outer surface of the ball 4 within the pocket portion 8 .

The plurality of pairs of claw portions 7 are positioned radially inward toward the tips of the claw portions 7 . That is, each pair of claw portions 7 is inclined radially inward. Along with the radially inward inclination of the pair of claw portions 7, the pocket center Cp of the pocket portion 8 is radially inside the pocket center Cp when the pair of claw portions 7 are not radially inwardly inclined. located towards Therefore, the pocket portion pitch circle diameter PDp of the retainer 5 is smaller than the pocket portion pitch circle diameter PDp when the pair of claw portions 7 are not inclined radially inward. In addition, the pocket portion pitch circle Pp when the pair of claw portions 7 is not inclined radially inward is aligned in the circumferential direction between the outer ring raceway surface 2a of the outer ring 2 and the inner ring raceway surface 3a of the inner ring 3. It coincides with the ball pitch circle Pb, which is the rolling element pitch circle passing through the centers of the balls 4 that are housed in plurality. That is, the pocket portion pitch circle diameter PDp is smaller than the ball pitch circle diameter PDb, which is the rolling element pitch circle diameter. Alternatively, the plurality of pairs of claws 7 may simply be made smaller than the ball pitch circle diameter PDb rather than slanting inward in the radial direction. Specifically, the pocket pitch diameter PDp is between 90 percent and 99.5 percent of the ball pitch diameter PDb. The ball pitch circle Pb is a circle centered on the axis of the outer ring 2 or the inner ring 3 .

Since the plurality of balls 4 are accommodated between the outer ring raceway surface 2a of the outer ring 2 and the inner ring raceway surface 3a of the inner ring 3, they do not move in the radial direction of the outer ring 2 or the inner ring 3. Therefore, the size of the ball pitch circle diameter PDb does not change even if the plurality of balls 4 are held by the retainer 5 having the pocket portion pitch circle diameter PDp different from the ball pitch circle diameter PDb. Therefore, the pocket center Cp of the retainer 5 holding the plurality of balls 4 is positioned radially inward with respect to the ball center Cb of the balls 4 . That is, the concave curved surface 8a of the pocket portion 8 is positioned radially inward with respect to the outer surface of the ball 4 .

When the retainer is not rotating in the circumferential direction with respect to the outer ring 2 and the inner ring 3 of the rolling bearing 1, the balls held by the plurality of pocket portions 8 extend from the radially inner end portions of the plurality of pocket portions 8. 4 is greater than the radial gap G2 from the radially outer end of the plurality of pocket portions 8 to the ball 4 held by each of the plurality of pocket portions 8 . A radially outer end of the pocket portion 8 is in contact with the ball 4 held by the pocket portion 8 . Accordingly, the concave curved surface 8a of the pocket portion 8 radially separates from the outer peripheral surface of the ball 4 as viewed in the axial direction from the radially outer end toward the radially inner end. Thus, the radial gap G1 between the radially inner end portion of the pocket portion 8 and the ball 4 is larger than when the pocket portion pitch circle Pp and the ball pitch circle Pb match. Also, the radial gap between the radially outer end of the pocket portion 8 and the ball 4 is G2, which is smaller than when the pocket portion pitch circle Pp and the ball pitch circle Pb match.

Next, with reference to FIGS. 7 and 8, the state of the retainer 5 when the rolling bearing 1 is rotating will be described. FIG. 7 is an enlarged plan view of the rolling bearing 1 when centrifugal force acts on the retainer 5 that retains the balls 4 . FIG. 8 is an enlarged axial sectional view of the rolling bearing 1 when centrifugal force acts on the retainer 5 that retains the balls 4 . In the rolling bearing 1, a plurality of balls 4 roll on the outer ring raceway surface 2a or the inner ring raceway surface 3a by rotation about the axis of the outer ring 2 or the inner ring 3 (see FIG. 1).

As shown in FIGS. 7 and 8, as the balls 4 roll, the retainer 5 holding the balls 4 rotates around the outer ring 2 or the inner ring 3 with the axis of the rolling bearing 1 as the rotation axis. It rotates in the circumferential direction. The retainer 5 is pushed outward in the radial direction by centrifugal force. The amount of elastic deformation of the retainer 5 that is pushed outward in the radial direction is determined by the rotational speed of the retainer 5, the radial distance from the axis to an arbitrary portion, and the geometrical moment of inertia of the arbitrary portion. In the retainer 5 , the elastic deformation amount of the plurality of claw portions 7 having a smaller geometrical moment of inertia than that of the base portion 6 is large.

The plurality of pairs of claws 7 are elastically deformed radially outward by centrifugal force (see arrows). The plurality of pairs of claw portions 7 are less inclined with respect to the axis. The pocket centers Cp of the plurality of pocket portions 8 of the retainer 5 move radially outward due to the radially outward elastic deformation of the plurality of pairs of claw portions 7 . As a result, the pocket portion pitch circle Pp of the retainer 5 increases radially outward about the axis. That is, the pocket center Cp approaches the ball center Cb.

The concave surfaces 8a of the plurality of pocket portions 8 move radially outward as the pocket center Cp moves radially outward. Therefore, the radially inner end portions of the plurality of pocket portions 8 move toward the outer surfaces of the balls 4 held by the plurality of pocket portions 8 . On the other hand, the radially outer ends of the plurality of pocket portions 8 move away from the outer surface of the ball 4 held by each of the plurality of pocket portions 8 . The radially outer end of the pocket portion 8 that was in contact with the outer surface of the ball 4 leaves the outer surface of the ball 4 . Thus, the distance between the concave curved surface 8a and the outer surface of the ball 4 becomes uniform as the pocket center Cp approaches the ball center Cb. In addition, the radially inner ends of the plurality of pocket portions 8 do not contact the outer surface of the ball 4 until the pocket portion pitch circle diameter PDp becomes larger than the ball pitch circle diameter PDb.

In the retainer 5 of the rolling bearing 1 configured in this manner, the pocket portion pitch circle Pp is positioned radially inward of the ball pitch circle Pb by tilting the claw portions 7 radially inward. Furthermore, in the retainer 5 , the radius of curvature Dp of the pocket portion 8 is larger than the radius of curvature Db of the balls 4 . That is, the radial gap G1 from the radially inner end of the plurality of pocket portions 8 of the retainer 5 to the balls 4 held by the plurality of pocket portions 8 is It is larger than the radial gap G2 from the outer end to the balls 4 held by the plurality of pocket portions 8 respectively. Further, in the retainer 5, an upper limit value and a lower limit value of the pocket portion pitch circle diameter PDp with respect to the ball pitch circle diameter PDb are defined. Therefore, the rolling bearing 1 has a gap of an appropriate size between the concave surface 8 a of the pocket portion 8 and the outer surface of the ball 4 . At this time, the radially outer ends of the concave curved surfaces 8a of the plurality of pocket portions 8 are in contact with the outer surface of the ball 4 being held.

When the rolling bearing 1 rotates about the axis as the rotation axis, the plurality of pairs of claws 7 of the retainer 5 elastically deform radially outward due to the centrifugal force generated according to the rotation speed. In the retainer 5 , the radially inner end portion of the pocket portion 8 approaches the outer surface of the ball 4 due to the radially outward elastic deformation of the plurality of pairs of claw portions 7 . However, the radially inner ends of the plurality of pairs of claws 7 do not contact the balls 4 until the pocket portion pitch circle diameter PDp becomes larger than the ball pitch circle diameter PDb due to elastic deformation radially outward. .

In addition, since the retainer 5 has a lower limit value and an upper limit value for the thickness t0 in the axial direction from the distal end surface 6a to the proximal end surface 6b of the base portion 6, the weight of the base portion 6 can be suppressed and the plurality of pairs of The rigidity of the base portion 6 necessary for supporting the claw portion 7 is secured. Therefore, in the retainer 5, the amount of elastic deformation of the plurality of pairs of claw portions 7 due to centrifugal force is suppressed. As a result, interference between the plurality of balls 4 and the plurality of pairs of claw portions 7 can be suppressed even if the retainer 5 is elastically deformed by centrifugal force.

(Embodiment 2)
A rolling bearing 1A, which is an exemplary embodiment 2 of the rolling bearing according to the present invention, will be described below with reference to FIG. FIG. 9 is an enlarged plan view of a cage 5A that holds balls 4 in a rolling bearing 1A according to Embodiment 2 of the present invention. In the following description, the same reference numerals are given to the same configurations as in the first embodiment, and the description thereof is omitted, and only the portions different from the first embodiment will be described.

As shown in FIG. 9, the rolling bearing 1A has a retainer 5A. The retainer 5A has a base portion 6, a plurality of pairs of claw portions 7, and a pocket portion 8A. The pocket portion 8A has side surfaces facing each other at the pair of claw portions 7 and a concave curved surface 8Aa for holding the ball 4 on the base portion 6 positioned between the pair of claw portions 7 . The concave curved surface 8Aa of the pocket portion 8A constitutes a part of the elliptical surface Ve. The concave curved surface 8Aa is formed based on an elliptical surface Ve whose major axis is the radial direction of the rolling bearing 1A. Therefore, the concave curved surface 8Aa is separated from the outer surface of the ball 4 in the circumferential and radial directions of the rolling bearing 1A as viewed in the axial direction from the radially outer end toward the radially inner end.

In the retainer 5A, the pocket portion pitch circle Pp passing through the pocket centers Cp of the plurality of pocket portions 8A is determined with the center of curvature Cp, which is the intersection of the major axis and the minor axis of the elliptical surface Ve, as the pocket center Cp. The pocket portion pitch circle Pp is a circle centered on the axis of the retainer 5A. The elliptical surface Ve is an elliptical surface whose major axis and minor axis are larger than the diameter of the ball 4 . That is, the average curvature radius Dp of the concave surface 8Aa of the pocket portion 8A is larger than the curvature radius Db of the ball 4 held in the pocket portion 8A. Therefore, a gap is generated between the concave curved surface 8Aa of the pocket portion 8A and the surface of the ball 4 inside the pocket portion 8A. The pocket portion 8</b>A has a pocket center Cp positioned so that the pocket portion pitch circle Pp passes through substantially the center in the radial direction of the plurality of pairs of claw portions 7 when viewed in the axial direction.

Thus, the retainer 5A is configured such that the radially inner end portion of the pocket portion 8A is radially separated from the balls 4 . Therefore, the radial gap G1 between the radially inner end of the pocket portion 8A and the ball 4 is larger than when the concave curved surface 8Aa is a part of the spherical surface Vs (see FIG. 5). As a result, interference between the balls 4 and the cage 5A can be further suppressed even if the cage 5A is elastically deformed by centrifugal force.

(Embodiment 3)
A rolling bearing 1B, which is an exemplary embodiment 3 of the rolling bearing according to the present invention, will be described below with reference to FIG. FIG. 10 is an enlarged plan view of retainer 5B that retains balls 4 in rolling bearing 1B according to Embodiment 3 of the present invention.

As shown in FIG. 10, the rolling bearing 1B has a retainer 5B. The retainer 5B has a base portion 6, a plurality of pairs of claw portions 7, and a pocket portion 8B. The retainer 5B of the rolling bearing 1 has a plurality of pocket portions 8B that hold the balls 4 from the plurality of pairs of claw portions 7 and the base portion 6 between the plurality of pairs of claw portions 7 . The plurality of pocket portions 8B have concave surfaces 8Ba for holding the ball 4 on side surfaces facing each other in the pair of claw portions 7 and the base portion 6 located between the pair of claw portions 7. As shown in FIG. Each of the plurality of pocket portions 8B has a concave curved surface 8Ba that closes toward the pair of claw portions 7 in the axial direction.

Furthermore, the retainer 5B has chamfered portions 8Bb that connect the concave curved surfaces 8Ba of the plurality of pocket portions 8B and the inner peripheral surface of the retainer 5B. The chamfered portion 8Bb is a slant surface in which the radius of the radially inner end of each of the pocket portions 8B increases as the radially inner end of the plurality of pocket portions 8B goes radially inward. That is, the chamfered portion 8Bb is an inclined surface that separates from the outer surface of the ball 4 held in each of the plurality of pocket portions 8B as it goes radially inward. Therefore, in the retainer 5B, the amount of radially outward elastic deformation of the pair of claw portions 7 required for the radially inner end portion of the pocket portion 8B to contact the ball 4 increases. As a result, even if the retainer 5B is elastically deformed by centrifugal force, interference between the rolling elements and the retainer 5B can be further suppressed.

(Other embodiments)
In the embodiments described above, the rolling bearings 1, 1A, 1B are configured as deep groove ball bearings. However, the rolling bearing may be a rolling bearing that retains a plurality of balls accommodated in the outer ring raceway surface and the inner ring raceway surface with a retainer. The rolling bearing may be, for example, an angular contact ball bearing or a wheel bearing device.

In the above-described embodiments, the cages 5, 5A, 5B are made of resin. It is desirable that the resin forming the retainer is a synthetic resin having a glass transition temperature of 120° C. or higher. As a result, softening of the retainer due to temperature rise during rotation is suppressed. Therefore, the rolling bearing can suppress interference between the rolling elements and the cage even if the cage elastically deforms due to centrifugal force when the temperature rises.

In the above-described embodiments, the cages 5, 5A, 5B are made of resin. The retainer may be formed by injection molding. In this case, the retainer is preferably injection molded such that the welds are located at the base. In the retainer, the welds are positioned at the base, which is stronger than the claws, so that the strength of the claws can be suppressed from being reduced by the welds.

In the above-described embodiment, the plurality of pairs of claw portions 7 of the cages 5, 5A, 5B are inclined radially inward. However, in the retainer, the concave curved surface of the pocket portion may be part of an elliptical surface with the major axis in the radial direction, while the claw portion is not inclined radially inward. In the retainer, the radially inner end faces of the pocket portions are less likely to come into contact with the balls even if the claw portions are elastically deformed radially outward by centrifugal force. Thereby, the rolling bearing can suppress interference between the rolling elements and the cage even if the cage is elastically deformed by centrifugal force.

Although the embodiments of the present invention have been described above, the present invention is not limited to such embodiments in any way, and is merely an example. Of course, the scope of the present invention is indicated by the description of the claims, and the meaning of equivalents described in the claims and all changes within the scope include.

Reference Signs List 1, 1A, 1B Rolling bearing 2 Outer ring 2a Outer ring raceway surface 3 Inner ring 3a Inner ring raceway surface 4 Balls 5, 5A, 5B Cage 6 Base 6a Tip surface 6b Base end surface 7 Pair of claws 8 Pocket 8a Concave surface Dp Pocket radius of curvature Db radius of curvature of ball Cp center of pocket Cb center of ball Pp pocket pitch circle Pb ball pitch circle PDp pocket pitch circle diameter PDb ball pitch circle diameter

Claims (10)

an outer ring having an outer ring raceway surface on its inner peripheral surface;
an inner ring positioned inside the outer ring and having an inner ring raceway surface on its outer peripheral surface;
a plurality of rolling elements interposed between the outer ring raceway surface and the inner ring raceway surface;
a retainer having a plurality of pocket portions that retain the rolling elements,
A rolling bearing in which the retainer comprises an annular base portion and a plurality of pairs of claw portions extending in the axial direction and positioned at regular intervals in the circumferential direction of the axial end face of the base portion,
The plurality of pocket portions of the retainer are
comprising the base and the plurality of pairs of claws, the plurality of pairs of claws being inclined radially inward with respect to the axis, and having curved surfaces for holding the rolling elements;
The pocket portion pitch circle diameter passing through the center of curvature of the curved surface of each of the plurality of pocket portions is
smaller than the rolling element pitch circle diameter passing through the centers of the plurality of rolling elements,
rolling bearing. A rolling bearing according to claim 1,
The retainer is
Of the two axial end faces of the base portion, the thickness from the base end face not having the claw portion to the tip end face between the adjacent pocket portions is greater than the thickness from the base end face to the bottom faces of the plurality of pocket portions. Larger and smaller than the length from the base end surface to the center of curvature of the curved surfaces of the plurality of pocket portions,
rolling bearing. In the rolling bearing according to claim 1 or 2,
The retainer is
curved surfaces of the plurality of pocket portions are along an elliptical surface whose major axis is the radial direction of the retainer;
rolling bearing. In the rolling bearing according to any one of claims 1 to 3,
The retainer is
When not rotating in the circumferential direction, the radial gaps in the retainer from the radially inner ends of the plurality of pocket portions to the rolling elements held by the plurality of pocket portions are larger than the radial gap in the retainer from the radially outer ends of the plurality of pocket portions to the rolling elements held by the plurality of pocket portions,
rolling bearing. In the rolling bearing according to any one of claims 1 to 4,
The retainer is
When not rotating in the circumferential direction, the radially outer ends of the plurality of pocket portions and the rolling elements held by the plurality of pocket portions are in contact with each other,
rolling bearing. In the rolling bearing according to any one of claims 1 to 5,
The retainer is
a chamfered portion connecting the curved surfaces of the plurality of pocket portions and the inner peripheral surface of the retainer;
rolling bearing. In the rolling bearing according to any one of claims 1 to 6,
The retainer is
The curvature radius of the curved surface of the pocket portion is 1.01 times or more and 1.10 times or less than the radius of the rolling element,
rolling bearing. In the rolling bearing according to any one of claims 1 to 7,
The retainer is
the pocket pitch diameter is between 90 percent and 99.5 percent of the rolling element pitch diameter;
rolling bearing. In the rolling bearing according to any one of claims 1 to 8,
The retainer is
composed of a resin material having a glass transition temperature of 120 degrees or higher,
rolling bearing. A rolling bearing according to claim 9,
The retainer is
The weld part generated during injection molding is located at the base,
rolling bearing.

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