Crown shaped retainer

Abstract

Provided is a crown-shaped retainer (20), including: an annular base (22); a plurality of pockets (24) each penetrating the crown-shaped retainer in a radial direction thereof and having an opening (a) on one side of the crown-shaped retainer in an axial direction thereof; and a pair of prongs (26) positioned on both sides of the opening (a) of each of the plurality of pockets (24) in a circumferential direction of the crown-shaped retainer, the each of the plurality of pockets (24) having an inner circumferential surface including: a spherical portion (28) positioned on a radially inner side of the crown-shaped retainer; and a cylindrical portion (30) positioned on a radially outer side of the crown-shaped retainer, the cylindrical portion (30) having an inner diameter ( D2) larger than a ball diameter (dw).

Claims

1. A crown-shaped retainer, comprising: an annular base; a plurality of pockets each penetrating the crown-shaped retainer in a radial direction thereof and having an opening on one side of the crown-shaped retainer in an axial direction thereof; and a pair of prongs positioned on both sides of the opening of each of the plurality of pockets in a circumferential direction of the crown-shaped retainer, wherein each of the plurality of pockets has an inner circumferential surface comprising: a spherical portion positioned on a radially inner side of the crown-shaped retainer; and a cylindrical portion positioned on a radially outer side of the crown-shaped retainer, and the cylindrical portion and the spherical portion have inner diameters larger than a ball diameter.

2. The crown-shaped retainer according to claim 1, wherein the crown-shaped retainer comprises a molded retainer, which is formed by die casting.

3. The crown-shaped retainer according to claim 2, wherein a material of the crown-shaped retainer is one selected from the group consisting of a magnesium alloy, an aluminum alloy, and a zinc alloy.

4. The crown-shaped retainer according to claim 3, wherein the crown-shaped retainer is used for a ball bearing having a dmn value of more than 600,000.

5. The crown-shaped retainer according to claim 4, wherein the crown-shaped retainer is used for a ball bearing for a transmission.

6. The crown-shaped retainer according to claim 3, wherein the crown-shaped retainer is used for a ball bearing for a transmission.

7. The crown-shaped retainer according to claim 2, wherein the crown-shaped retainer is used for a ball bearing for a transmission.

8. The crown-shaped retainer according to claim 2, wherein the crown-shaped retainer is used for a ball bearing having a dmn value of more than 600,000.

9. The crown-shaped retainer according to claim 8, wherein the crown-shaped retainer is used for a ball bearing for a transmission.

10. The crown-shaped retainer according to claim 1, wherein the crown-shaped retainer is used for a ball bearing having a dmn value of more than 600,000.

11. The crown-shaped retainer according to claim 10, wherein the crown-shaped retainer is used for a ball bearing for a transmission.

12. The crown-shaped retainer according to claim 1, wherein the crown-shaped retainer is used for a ball bearing for a transmission.

13. A ball bearing comprising: an inner race having a raceway formed on an outer circumference thereof; an outer race having a raceway formed on an inner circumference thereof; a plurality of balls interposed between the raceway of the inner race and the raceway of the outer race; and a crown-shaped retainer according to claim 1 that retains the balls at predetermined intervals in a circumferential direction.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1(A) is a partial developed plan view of a retainer according to an example of the present invention.

(2) FIG. 1(B) is a partial sectional view of the retainer according to the example of the present invention.

(3) FIG. 2 is a sectional view of a ball bearing.

(4) FIG. 3 is a perspective view of a retainer according to the related art.

(5) FIG. 4(A) is a partial developed plan view of the retainer of FIG. 3.

(6) FIG. 4(B) is a partial sectional view of the retainer of FIG. 3.

(7) FIG. 5 is a table showing a list of properties of respective retainer materials.

DESCRIPTION OF EMBODIMENTS

(8) Now, an embodiment of the present invention is described with reference to the accompanying drawings.

(9) Note that, the same parts or components as those of the related-art crown-shaped retainer that is already described with reference to FIGS. 2, 3, 4A, and 4B are represented by the same reference symbols, and redundant description is therefore omitted herein.

(10) FIGS. 1A and 1B illustrate an example of a crown-shaped retainer 20. The entire outer appearance of the crown-shaped retainer 20 is similar to that of the related-art crown-shaped retainer illustrated in FIGS. 4A and 4B. The crown-shaped retainer 20 comprises an annular base 22, a plurality of pockets 24, and a pair of prongs 26 each protruding in an axial direction of the retainer from an opening of each pocket 24. Further, as understood from FIG. 1A, the pocket 24 is opened toward one side of the retainer 20 in the axial direction. Note that, FIG. 1A is a partial developed plan view of the retainer 20, and the vertical direction of FIG. 1A corresponds to the axial direction of the retainer. A separation distance between the pair of prongs 26, that is, a pocket inlet diameter a is set smaller than a ball diameter dw (a<dw).

(11) However, this crown-shaped retainer 20 is different from the crown-shaped retainer of FIGS. 4A and 4B in the shape of an inner circumferential surface of the pocket 24 as described below.

(12) As understood from FIG. 1B illustrating a cross section passing through the center of the pocket 24 of FIG. 1A, the pocket 24 penetrates the retainer 20 in a radial direction. Further, the inner circumferential surface of each pocket 24 comprises a spherical portion 28 positioned on a radially inner side of the retainer, and a cylindrical portion 30 positioned on a radially outer side of the retainer. The spherical portion 28 corresponds to a part of the spherical pocket 24 of the related-art crown-shaped retainer, and has an inner diameter slightly larger than the ball diameter dw. An end of the spherical portion 28 on the radially inner side of the retainer is an opening having an inner diameter D1 smaller than the ball diameter dw.

(13) An inner diameter D.sub.2 of the cylindrical portion 30 is slightly larger than the ball diameter dw. Accordingly, with the structure in which the inner diameter D.sub.2 of the pocket 24 on the radially outer side of the retainer is set larger than the ball diameter dw, when balls 18 are assembled into the pockets 24, respectively, the retainer 20 is tilted radially inward without being constrained by the balls 18 as indicated by the broken line arrows of FIG. 1B. That is, in the process of assembling the bearing, under a state in which an inner race 10, an outer race 14, and the balls 18 are assembled together, the retainer 20 is moved in the axial direction toward the balls 18 while the openings of the pockets 24 are set in phase with the balls 18. Then, the balls 18 are caused to enter the pockets 24, respectively, from the side where the inner diameters of the pockets 24 are larger ( D.sub.1< D.sub.2) , but the balls 18 are constrained by the inner race 10 and the outer race 14 in the radial direction, with the result that the retainer 20 is tilted radially inward. Note that, FIG. 1B illustrates a state in which the assembling of the balls 18 is completed, and hence the retainer 20 is already recovered from its tilt (elastic deformation). In this manner, the assembling of the balls 18 is facilitated, thereby being capable of assembling the balls 18 without causing any damage to the retainer 20, such as a crack.

(14) The retainer 20 is manufactured by die casting. As an alloy for die casting, various kinds of non-ferrous alloy are known. For example, as defined in JIS, zinc alloy die casting (JIS H 5301), aluminum alloy die casting (JIS H 5302), and magnesium alloy die casting (JIS H 5303) are employed, and a copper alloy, a lead alloy, a tin alloy, and the like are also employed. As shown in FIG. 5, even when the retainer material is changed from PEEK to materials for die-cast products, mechanical strength equal to or higher than that of PEEK can be secured. Also from the viewpoint of manufacture, the productivity is high because of die casting.

(15) A ball bearing using the above-mentioned crown-shaped retainer is applicable to such a high-speed rotation use that a dmn value is more than 600,000, in which the related-art crown-shaped retainer made of PEEK has been used. As such a use, for example, there may be given a ball bearing for supporting gears of a transmission.

(16) The embodiment of the present invention has been described by way of example illustrated in the drawings, but the present invention maybe carried out through various modifications without departing from the scope of claims.

REFERENCE SIGNS LIST

(17) 10 inner race

(18) 12 raceway

(19) 14 outer race

(20) 16 raceway

(21) 18 ball

(22) 20 retainer

(23) 22 annular base

(24) 24 pocket

(25) 26 prong

(26) 28 spherical portion

(27) 30 cylindrical portion