Rolling-element bearing, and method and apparatus for manufacturing rolling-element bearing

Abstract

A rolling-element bearing in which a rolling element is retained in each of retaining openings formed in a retainer and method for manufacturing the bearing are provided. Each retaining opening is defined by a pair of inner side faces facing each other, and a pair of inner end faces facing each other. In the manufacturing method, with a support die being brought into contact with one of the inner side faces and the inner end faces of one of the retaining openings, the outer and inner circumferential surfaces of the retainer are pressed by an outer punch and an inner punch. Accordingly, on at least one of the inner side faces and the inner end faces, a first retaining piece and a second retaining piece for preventing the rolling element from falling off are formed on the outer circumferential surface and the inner circumferential surface of the retainer, respectively.

1 . A rolling-element bearing comprising:
 a cylindrical retainer having a plurality of retaining openings formed in a circumferential wall, wherein each of the retaining openings is defined by a pair of inner side faces, which face each other, and a pair of inner end faces, which face each other; and   a plurality of rolling elements, each of which is rotationally accommodated in one of the retaining openings, wherein   each inner side face extends along a plane that contains an axis of the retainer, and each inner end face extends along a plane that contains a line perpendicular to the axis, and   at least one first retaining piece and at least one second retaining piece are formed in each retaining opening of the retainer by pressing the outer circumferential surface and the inner circumferential surface of the retainer, respectively, wherein the first retaining piece and the second retaining piece are located on at least one of the inner side faces and the inner end faces, and the first retaining piece and the second retaining piece are located on the outer circumferential surface and the inner circumferential surface of the retainer, respectively.   
     
     
         2 . A method for manufacturing a rolling-element bearing, wherein a rolling element is accommodated in each of a plurality of retaining openings formed in a circumferential wall of a cylindrical retainer, and each of the retaining opening is defined by a pair of inner side faces, which face each other, and a pair of inner end faces, which face each other, the method comprising:
 bringing a support die into contact with one of the inner side faces and the inner end faces of one of the retaining opening;   with the support die in contact, pressing the outer circumferential surface and the inner circumferential surface of the retainer, thereby forming at least one first retaining piece on the outer circumferential surface and at least one second retaining piece on the inner circumferential surface of the retainer;   accommodating the rolling element in the retaining opening; and   after accommodating the rolling element, bending the at least one first retaining piece and the at least one second retaining piece such that the first retaining piece and the second retaining piece retain the rolling element in the retaining opening.   
     
     
         3 . The method for manufacturing a rolling-element bearing according to  claim 2 , wherein the forming the at least one first retaining piece and the at least one second retaining piece includes simultaneously pressing the outer circumferential surface and the inner circumferential surface of the retainer from outside and inside in the radial direction of the retainer. 
     
     
         4 . The method for manufacturing a rolling-element bearing according to  claim 2 , wherein
 the inner side faces of each retaining opening extend along the axis of the retainer, and   the forming the at least one first retaining piece and the at least one second retaining piece includes forming the at least one first retaining piece and the at least one second retaining piece on at least one of the inner side faces of the retaining opening so that the at least one first retaining piece and the at least one second retaining piece protrude in radial direction as the axis of the retainer as the center.   
     
     
         5 . An apparatus for manufacturing a rolling-element bearing, wherein a rolling element is accommodated in each of a plurality of retaining openings formed in a circumferential wall of a cylindrical retainer, and each of the retaining openings is defined by a pair of inner side faces, which face each other, and a pair of inner end faces, which face each other, the apparatus comprising:
 a support die for supporting one of the inner side faces and the inner end faces of one of the retaining opening;   a first punch that presses the retainer, thereby forming at least one first retaining piece and at least one second retaining piece on the face supported by the support die; and   a second punch for bending the first retaining piece and the second retaining piece formed by the first punch toward the retaining opening.   
     
     
         6 . The manufacturing apparatus according to  claim 5 , wherein the first punch includes:
 at least one first outer punch for pressing, from radially outside of the retainer, at least a part of the outer circumferential surface of the retainer that is close to the face supported by the support die, thereby forming the at least one first retaining piece, which is located on the face supported by the support die and on the outer circumferential surface of the retainer; and   a first inner punch having at least one punch portion for pressing, from radially inside of the retainer, at least a part of the inner circumferential surface of the retainer that is close to the face supported by the support die, thereby forming the at least one second retaining piece, which is located on the face supported by the support die and on the inner circumferential surface of the retainer, and   wherein the first outer punch and the first inner punch simultaneously press the retainer.