JP2000002245A - Plastic cage for thrust ball bearings - Google Patents

Abstract

(57) [Summary] [Problem] A plastic for a thrust ball bearing capable of holding a ball having a ball diameter equal to or larger than that of a copper alloy machined cage and increasing the number of balls in a circumferential direction. Provide a cage made of. SOLUTION: Plastic retainer for thrust bearing 1
Is formed in an annular plate shape by injection molding of a synthetic resin, and a plurality of spherical pockets 2 that hold the balls rotatably are provided at equal intervals in the circumferential direction. At the peripheral edge of the opening of each pocket 2, a ball drop-off prevention convex portion 3 that elastically engages with the ball to prevent the ball from falling off is provided so as to protrude radially inward of the pocket 2. Here, the convex portion 3 for preventing the ball from falling off
Are arranged at two locations 180 ° apart from each other in the circumferential direction of the pocket 2, and furthermore, a line L connecting each ball drop prevention projection 3 is formed.
₁ and a line L connecting the center of the cage 1 and the center of the pocket 2
₂ is set to 40 to 60 °.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic cage for a thrust ball bearing having a plurality of circular or spherical pockets which are formed in an annular plate shape and hold a ball so as to be able to roll. About.

[0002]

2. Description of the Related Art As a retainer for a thrust ball bearing, for example, a copper alloy piercing retainer a shown in FIGS. 3 and 4, and plastic retainers b and c shown in FIGS. 5 and 6 are generally known. ing.

[0003] The copper alloy machined retainer a prevents the ball f held in the pocket d from dropping off by caulking a plurality of locations e in the circumferential direction at the periphery of the opening of the circular pocket d. .

On the other hand, the cages b and c made of plastic are manufactured by injection molding, and ball drop-off prevention convex portions h which elastically engage with the ball are provided at a plurality of circumferential positions on the peripheral edge of the opening of each pocket g. The pocket g is provided so as to protrude inward in the radial direction, thereby preventing the ball pushed into the pocket g from falling off.

[0005]

However, in the above-mentioned conventional plastic cages b and c, it is necessary to secure a space for providing the ball drop-off prevention convex portion h at the peripheral edge of the opening of the pocket g, and therefore, the copper Alloy machined cage a
In comparison with the above, it is necessary to reduce the ball diameter and the number of balls in the circumferential direction for the same bearing cross-sectional dimension.

SUMMARY OF THE INVENTION The present invention has been made in order to solve such a disadvantage, and can hold a ball having a diameter equal to or larger than that of a copper alloy machined cage, and has a number of balls in a circumferential direction. It is an object of the present invention to provide a plastic cage for a thrust ball bearing, which can increase the number of bearings.

[0007]

In order to achieve the above object, a plastic cage for a thrust bearing according to the present invention is formed in an annular plate shape and has a circular or spherical shape for holding a ball in a rolling manner. A plurality of pockets are provided in the circumferential direction, and a ball drop-off preventing convex portion that elastically engages with the ball to prevent the ball from dropping is provided on the opening peripheral portion of each pocket in a radially inward direction of the pocket. In a plastic cage for a thrust ball bearing protruding from the pocket, the ball drop-off preventing protrusions are arranged at two places 180 ° apart from each other in the circumferential direction of the pocket, and further, each ball drop-off preventing protrusion is provided. An angle α between a line connecting the parts and a line connecting the center of the retainer and the center of the pocket is set to 40 to 60 °.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a partial plan view for explaining a plastic cage for a thrust bearing which is an example of an embodiment of the present invention, and FIG. 2 is a sectional view taken along line II-II of FIG.

The plastic cage 1 for a thrust bearing is formed in an annular plate shape by injection molding of a synthetic resin, and a spherical pocket 2 for rollingly holding a ball (not shown) is circular. A plurality of portions are provided at equal intervals in the circumferential direction. At the peripheral edge of the opening of each pocket 2, a ball drop-off prevention convex portion 3 that elastically engages with the ball to prevent the ball from falling off is provided so as to protrude radially inward of the pocket 2. When the ball is inserted into the pocket 2, a groove 4 is provided in the ball drop-off prevention convex portion 3 for facilitating elastic deformation of the ball drop-off prevention convex portion 3 and enabling smooth insertion of the ball. Have been.

[0010] In this embodiment, the ball is prevented from falling off.
The projections 3 are separated from each other by 180 ° in the circumferential direction of the pocket 2.
And place them at two places, and further connect the balls 3
Line L ₁And the center of the cage 1 and the center of the pocket 2
Line L_TwoAnd the angle α between 40 and 60 degrees.
As a result, the two projections 3 for preventing the ball from falling off are opened in the pocket 2.
At the peripheral edge, the thickness of the cage 1 in the circumferential direction is
It is located at a certain position.

As described above, in this embodiment, the two ball drop-off preventing projections 3 are arranged at positions where the thickness of the cage 1 is the largest in the circumferential direction at the peripheral edge of the opening of the pocket 2. Therefore, the inner diameter of the pocket 2 can be enlarged to increase the ball diameter, and the interval between the pockets 2 in the circumferential direction can be reduced to increase the number of balls in the circumferential direction. As a result, the bearing load capacity can be increased. It is possible to provide a thrust ball bearing having an allowable rated load equal to or higher than that of the copper alloy machined cage.

In the above-described embodiment, the case where the shape of the pocket 2 is spherical is taken as an example, but the present invention can of course be applied to a circular pocket.

[0013]

As is apparent from the above description, according to the present invention, the space of the retainer can be reduced by changing the circumferential phase of the ball drop-off preventing convex portion at the peripheral edge of the opening of the pocket. By effectively utilizing the two ball drop-off prevention protrusions at the peripheral edge of the opening at the position where the thickness of the cage is the largest in the circumferential direction of the cage, the inner diameter of the pocket is enlarged. The ball diameter can be increased, and the number of balls in the circumferential direction can be increased by narrowing the interval between each pocket in the circumferential direction. As a result, it is possible to maintain and improve the bearing load capacity. Thus, an effect is obtained in that a thrust ball bearing having an allowable rated load equal to or greater than that of the case where the copper alloy-made hollow cage is used can be provided.

[Brief description of the drawings]

FIG. 1 is a partial plan view illustrating a plastic retainer for a thrust bearing which is an example of an embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a partial plan view for explaining a copper alloy machined retainer used for a thrust bearing.

FIG. 4 is a sectional view taken along line IV-IV of FIG. 3;

FIG. 5 is a partial plan view of a conventional plastic cage for a thrust bearing.

FIG. 6 is a partial plan view of a conventional plastic cage for a thrust bearing.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Plastic retainer for thrust ball bearings 2 ... Pocket 3 ... Ball projection prevention part

Claims (1)

[Claims] 1. A plurality of circular or spherical pockets formed in an annular plate shape and holding a ball so as to be able to roll are provided in a circumferential direction, and the ball is elastically attached to an opening peripheral portion of each pocket. In a plastic retainer for a thrust ball bearing provided with a ball drop-off preventing convex portion that is engaged to prevent the ball from falling off, protruding radially inward of the pocket, the ball drop-off preventing convex portion is An angle α between a line connecting the convex portions for preventing the balls from falling off and a line connecting the center of the retainer and the center of the pocket is disposed at two places spaced apart by 180 ° in the circumferential direction of the pocket. 40 to 60 °, a plastic cage for a thrust ball bearing.