JP2011185315A - Rolling bearing and retainer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rolling bearing and a retainer capable of reducing a contact surface pressure of a contact part of a ball and retainer pocket inner surfaces, expanding a contact area and sufficiently securing axial clearances of retainer pockets. <P>SOLUTION: The retainer 4 is a ring-like shape including ring-like parts 4a provided at both sides in an axial direction and a plurality of column parts 4b for connecting these ring-like parts 4a. The plurality of column parts 4b are respectively arranged to extend in the axial direction from a plurality of positions in a circumferential direction of the ring-like parts 4a and form the pocket Pt for mutually holding the ball 3 between each other. In the retainer 4, the plurality of pockets Pt are lined up in the circumferential direction in the middle in the axial direction. As for the form of the respective pocket Pt in a radial direction view, its circumferential center part is arranged as a straight line part 5 extending in the circumferential direction and both circumferential side parts of the pocket Pt continuing to the straight line part 5 is arranged as an elliptical part 6 in a semi-elliptical form of which major axis is arranged in the circumferential direction. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a rolling bearing and a cage, for example, to a technique applied to a cage having self-lubricating properties such as a rocket engine turbo pump bearing.

  Conventionally, as shown in FIG. 7, the contact surface pressure of the contact portion between the ball 50 and the inner surface of the cage pocket 51 is lowered, the contact area of the contact portion is increased, and the cage 52 moves to the rolling surface of the ball 50. A technique for increasing the supply of self-lubricant and reducing the wear of the contact surface with the ball 50 on the inner surface of the cage pocket 51 has been proposed (Patent Document 1). In this technique, with respect to the shape of each pocket 51 seen in the radial direction, both sides in the circumferential direction of the cage pocket 51 are arcuate portions 53 made of a perfect circle, and the center in the circumferential direction of the cage pocket 51 is This is a so-called “flat circular shape” in which the linear portion 54 extends in the circumferential direction.

JP 58-180839 A Japanese Utility Model Publication No. 5-62734

In the above-described prior art, since both sides in the circumferential direction of the cage pocket 51 are the circular arc portions 53 having a perfect circle shape, the radius of the pocket 51 is restricted by the value of the axial clearance δ1 of the pocket 51. That is, in order to reduce the contact surface pressure between the ball 50 and the inner surface of the cage pocket 51 and increase the contact area, it is advantageous that the radius of the perfect circle of the arc portion 53 in the cage pocket 51 is made closer to the radius of the ball 50. It is. However, since both sides in the circumferential direction of the cage pocket 51 are formed in a perfect circle shape, the axial clearance δ1 of the cage pocket 51 is reduced, which causes an unreasonable force on the cage 52.
As shown in FIG. 8, the present applicant has proposed a technique for making the cage pocket shape an elliptical shape when viewed in the radial direction of the pocket 51, and the elliptical shape of the pocket 51 is the same as that of the cage pocket 51. Since it is determined by the circumferential clearance δ2 and the axial clearance δ1, there is no degree of freedom for decreasing the contact surface pressure between the ball 50 and the inner surface of the cage pocket 51 and increasing the contact area.

  An object of the present invention is to provide a rolling bearing and a holder capable of reducing the contact surface pressure of the contact portion between the ball and the inner surface of the cage pocket, increasing the contact area, and ensuring sufficient and sufficient axial clearance of the cage pocket. Is to provide a vessel.

The rolling bearing according to the present invention is a rolling bearing including a ring-shaped cage that holds a plurality of balls interposed between the raceway surfaces of the inner and outer rings. The cage has a plurality of pockets each holding each ball in a circular shape. The pockets that are provided in the “middle of the axial direction” side by side in the circumferential direction, and the shape seen in the radial direction of each pocket is a linear portion extending in the circumferential direction at the circumferential central portion, and the pocket connected to the linear portion The both sides in the circumferential direction are shaped like an ellipse having a semi-elliptical shape whose major axis is the circumferential direction.
The “middle in the axial direction” is not necessarily limited to the axial center position of the cage.

  According to this configuration, since both sides in the circumferential direction of the pocket of the cage are elliptical portions having a semi-elliptical shape whose major axis is the circumferential direction, the contact surface pressure between the ball and the pocket inner surface of the cage is reduced. The contact area can be increased. Furthermore, since the circumferential central portion of the pocket of the cage is a linear portion extending in the circumferential direction, a sufficient axial clearance of the pocket can be ensured. Therefore, it is possible to prevent an excessive force from being generated in the cage.

  The cage may be made of a material having at least an inner surface of the pocket having self-lubricating properties. During the bearing operation, the inner surface of the cage pocket comes into contact with the balls due to the rotation and revolution of the balls. At this time, a part of the self-lubricating material is transferred to the surface of the ball and the raceway surface of the inner and outer rings to provide a lubricating action. Therefore, the bearing life can be extended.

The cage may be made of a metal material or a resin material, and a self-lubricating film may be coated on at least the pocket inner surface of the cage. In this case, the material cost can be reduced as compared with the case where the entire cage is made of a material having self-lubricating properties.
The whole cage may be coated with the self-lubricating film. When coating a film on a part of the cage, it takes time and effort to mask an uncoated part. However, when coating a film on the entire cage, the number of manufacturing steps can be reduced.

  The balls may be made of ceramics. In this case, it is possible to reduce the weight of the ball made of bearing steel and to perform higher speed operation.

The cage of the present invention is a ring-shaped cage that is used in a ball bearing and has pockets for holding balls at a plurality of locations in the circumferential direction, and the cage has a plurality of pockets arranged in the circumferential direction. The shape seen in the radial direction of each pocket is a linear portion extending in the circumferential direction in the circumferential direction, and both sides in the circumferential direction of the pocket connected to the linear portion. Is a shape that is an ellipse having a semi-elliptical shape whose major axis is the circumferential direction.
Since both sides in the circumferential direction of the pocket of the cage are elliptical portions having a semi-elliptical shape whose major axis is the circumferential direction, the contact surface pressure between the ball and the pocket inner surface of the cage is reduced, and the contact area is reduced. Can be increased. Furthermore, since the circumferential central portion of the pocket of the cage is a linear portion extending in the circumferential direction, a sufficient axial clearance of the pocket can be ensured. Therefore, it is possible to prevent an excessive force from being generated in the cage.

  The rolling bearing according to the present invention is a rolling bearing including a ring-shaped cage that holds a plurality of balls interposed between the raceway surfaces of the inner and outer rings. The cage has a plurality of pockets each holding each ball in a circular shape. A circular shape of the pockets connected to the straight line portion, which is provided in the middle of the axial direction side by side in the circumferential direction, and the shape seen in the radial direction of each pocket is a straight line portion extending in the circumferential direction in the circumferential center portion. Since both sides in the circumferential direction have an elliptical shape with a semi-elliptical shape whose major axis is the circumferential direction, the contact surface pressure of the contact portion between the ball and the cage pocket inner surface is reduced, and the contact area is increased. In addition, the axial clearance of the cage pocket can be ensured sufficiently and sufficiently.

It is sectional drawing of the rolling bearing which concerns on one Embodiment of this invention. (A) is sectional drawing of the holder | retainer of the rolling bearing, (B) is the figure which carried out the partial fracture | rupture which looked at the holder | retainer in the radial direction of the pocket. It is a figure which expands and represents the shape which looked at each pocket of the holder | retainer in radial direction. It is a figure explaining the contact surface pressure and contact area of the pocket inner surface and ball | bowl of the same holder | retainer. It is a figure explaining the contact surface pressure and contact area of the pocket inner surface and ball | bowl of the holder | retainer of a prior art example. It is a figure explaining the contact surface pressure and contact area of the pocket inner surface of a cage of other conventional examples, and a ball. It is a figure which expands and represents the shape which looked at each pocket of the cage of the prior art example to radial direction. It is a figure which expands and represents the shape which looked at each pocket of the other conventional example to radial direction.

An embodiment of the present invention will be described with reference to FIGS.
As shown in FIG. 1, the rolling bearing according to this embodiment includes a plurality of balls 3 interposed between the raceway surfaces 1 a and 2 a of the inner ring 1 and the outer ring 2, and includes a cage 4 that holds the plurality of balls 3. It is a thing. This rolling bearing is an angular ball bearing, and a tapered surface 2 b serving as a counterbore is formed on the inner diameter of the front side of the outer ring 2. The tapered surface 2b is formed in a tapered shape having a larger diameter from the raceway surface 2a side toward the front end surface.
The inner and outer rings 1 and 2 are made of bearing steel, stainless steel, etc., each ball 3 is made of ceramics, and the cage 4 is made of a metal material or a resin material. When the cage material is the resin material, for example, a glass fiber reinforced polyamide resin or the like is used. However, these bearing components are not limited to the above materials, and various materials can be applied according to the use conditions of the bearings.

The cage 4 will be described.
As shown in FIG. 1, the guide method of the cage 4 is, for example, an inner ring guide method. As shown in FIGS. 2 and 3, the retainer 4 has a ring shape having an annular portion 4a provided on both sides in the axial direction and a plurality of pillars 4b connecting the annular portions 4a on both sides. The plurality of pillars 4b are provided extending in the axial direction from a plurality of locations in the circumferential direction of the annular portion 4a to form pockets Pt for holding the balls 3 therebetween. 2 and 3, the circumferential direction is represented by an arrow A1, and the axial direction is represented by A2.

  The cage 4 is provided with a plurality of the pockets Pt arranged in the circumferential direction in the middle in the axial direction. Furthermore, the shape of each pocket Pt viewed in the radial direction is a linear portion 5 extending in the circumferential direction at the center in the circumferential direction, and both long sides of the circumferential direction of the pocket Pt connected to the linear portion 5 are It is the shape made into the ellipse part 6 which consists of the semi-elliptical shape used as the said circumferential direction. The pocket Pt has a cross-sectional shape with a cross section of a cylindrical surface at an arbitrary radial position, and has a straight cylindrical shape composed of the linear portion 5 and the ellipse portion 6, and the pocket center extends in the cage radial direction. As shown in FIG. 3, when the ball 3 is disposed at the intermediate position in the axial direction of the pocket Pt of the cage 4 and at the intermediate position in the circumferential direction of the pocket Pt, the shortest in the axial direction between the linear portion 5 and the ball 3. The distance is “pocket axial clearance δ1”, and the circumferential distance between the circumferential position P1 of the elliptical portion 6 and the ball 3 is “pocket circumferential clearance δ2”. In other words, the value obtained by dividing the maximum axial displacement of the ball 3 with respect to the pocket Pt of the cage 4 by “2” is the axial clearance δ1 of the pocket Pt, and the maximum of the ball 3 with respect to the pocket Pt of the cage 4 A value obtained by dividing the circumferential displacement by “2” is the circumferential clearance δ2 of the pocket Pt.

  As shown in FIG. 2 (A), the retainer 4 is a plane including the axial direction represented by the arrow A2, and a cross section seen by cutting an arbitrary position in the circumferential direction of the retainer 4 An inner peripheral surface 4i guided by the inner ring outer diameter surface 1b (FIG. 1), an outer peripheral surface 4D formed with a uniform thickness from the inner peripheral surface 4i to the outer diameter side, and both ends of the inner and outer peripheral surfaces 4i and 4D It becomes the cylindrical shape which consists of the end surfaces 4h and 4h which connect.

As shown in FIGS. 2A and 3, the entire cage is coated with a film 7 having self-lubricating properties. This coating 7 prevents the balls 3 from coming into direct contact with the ball guide surfaces of the pockets Pt of the cage 4. As a material of the film 7, a main component may be a mixture containing at least one of resin, soft metal, and solid lubricant. The resin used as the material of the film 7 may be a synthetic resin.
The synthetic resin in this case is not particularly limited as long as it is a material that has oil resistance, has high film strength when formed into the film 7, and has excellent wear resistance. Examples of such a synthetic resin include PTFE, nylon, polyimide and the like.
When a soft metal is used as the material of the coating 7, the soft metal is preferably any one of copper, silver, gold, and indium. Further, when a solid lubricant is used as the material of the film 7, the main component of the solid lubricant is preferably molybdenum disulfide, tungsten disulfide, or graphite.

Here, the contact surface pressure and the contact area between the balls and the pocket inner surface of the cage are compared between the cage of the prior art and the cage according to the present embodiment.
5, the interference portion 8 between the ball 3 and the pocket inner surface formed when the coating 7 is worn (that is, a solid lubricating layer that can be transferred to the ball “FIG. 5 Layers represented by hatching” )), The contact length L between the ball 3 and the inner surface of the pocket and the interference area are each 100%. In this case, in the conventional cage having the elliptical pocket of FIG. 6, the contact length L = 138.1% and the interference area 120.7%, whereas in the cage 4 of the present embodiment shown in FIG. The contact length is 176.7% and the interference area is 207.6%.

  According to the rolling bearing described above, since both sides in the circumferential direction of the pocket Pt of the cage 4 are the elliptical portions 6 having a semi-elliptical shape whose major axis is the circumferential direction, the balls 3 and the pockets of the cage 4 are arranged. The contact surface pressure with the inner surface can be lowered and the contact area can be increased. Furthermore, since the central portion in the circumferential direction of the pocket Pt of the cage 4 is the linear portion 5 extending in the circumferential direction, the axial clearance δ1 of the pocket Pt can be ensured sufficiently and sufficiently. Therefore, it is possible to prevent an excessive force from being generated in the cage 4 and to extend the life of the cage as compared with the conventional cage.

  Since the cage 4 is made of a metal material or a resin material, and the entire cage is coated with a film 7 having self-lubricating properties, the material cost is lower than that of the cage made of a material having self-lubricating properties. Can be achieved. In addition, when the coating 7 is coated on the entire cage, there is no need for troubles such as masking a portion that is not coated, and the number of manufacturing steps can be reduced. In the case where the balls 3 are made of ceramics, it is possible to reduce the weight as compared with balls made of bearing steel or the like and to perform higher speed operation.

The guide method of the cage may be a rolling element guide method or an outer ring guide method.
The rolling bearing is not limited to an angular ball bearing, and may be a deep groove ball bearing. The cage incorporated in the deep groove ball bearing may have a so-called split structure composed of cage segments divided in the axial direction and may be assembled by pins or the like provided at regular intervals in the circumferential direction. The other cage configuration is the same as that of the above-described embodiment.
The self-lubricating film may be coated only on a part including at least the pocket inner surface of the cage. The cage itself may be made of a material having self-lubricating properties.

DESCRIPTION OF SYMBOLS 1 ... Inner ring 2 ... Outer ring 1a, 2a ... Raceway surface 3 ... Ball 4 ... Cage 5 ... Linear part 6 ... Ellipse part 7 ... Coat Pt ... Pocket

Claims (6)

In a rolling bearing provided with a ring-shaped cage for holding a plurality of balls interposed between raceway surfaces of inner and outer rings,
The cage is provided with a plurality of pockets for holding each ball in the middle in the axial direction along the circumferential direction, and the shape seen in the radial direction of each pocket is the circumferential central portion of the circumference. A rolling bearing characterized in that a linear portion extending in a direction is formed, and both sides in the circumferential direction of the pocket connected to the linear portion are in the shape of an ellipse having a semi-elliptical shape whose major axis is the circumferential direction. .   The rolling bearing according to claim 1, wherein at least the inner surface of the pocket is made of a material having a self-lubricating property.   2. The rolling bearing according to claim 1, wherein the cage is made of a metal material or a resin material, and a self-lubricating film is coated on at least the pocket inner surface of the cage.   The rolling bearing according to claim 3, wherein the entire cage is coated with the self-lubricating film.   The rolling bearing according to claim 1, wherein the balls are made of ceramics. A ring-shaped cage provided with pockets for holding balls at a plurality of locations in the circumferential direction used for ball bearings,
In this cage, a plurality of pockets are arranged in the circumferential direction in the middle of the axial direction, and the shape seen in the radial direction of each pocket is a linear portion extending in the circumferential direction at the center in the circumferential direction. The cage having a shape in which both sides in the circumferential direction of the pocket connected to the straight line portion are formed into an elliptical portion having a semi-elliptical shape whose major axis is the circumferential direction.

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