Abstract: A ball bearing retainer includes two annular members that face each other in an axial direction. The two annular members have opposed surfaces each including hemispherical pockets that are formed at a plurality of positions in a circumferential direction and configured to receive balls. The opposed surfaces are snap-fitted to each other so as to couple the two annular members to each other with coupling portions provided at both circumferential end portions of each of the hemispherical pockets Inner peripheral surfaces of the hemispherical pockets of the two annular members and the opposed surfaces of the two annular members have recessed grooves that are opened by extending from radially inner surfaces of the two annular members and reaching radially outer surfaces of the two annular members.

Abstract: Provided is a ball bearing retainer, comprising two annular members (10) that face each other in an axial direction, the two annular members (10) having opposed surfaces (11) each comprising hemispherical pockets (12) that are formed at a plurality of positions in a circumferential direction and configured to receive balls, the opposed surfaces (11) being snap-fitted to each other so as to couple the two annular members (10) to each other with coupling portions (18) provided at both circumferential end portions of each of the hemispherical pockets (12). Inner peripheral surfaces of the hemispherical pockets (12) of the two annular members (10) and the opposed surfaces (11) of the two annular members (10) comprise recessed grooves (19, 20) that are opened by extending from radially inner surfaces of the two annular members (10) and reaching radially outer surfaces of the two annular members (10).

Abstract: In a method of producing split bearings, comprising the steps of forming at least one of the two end surfaces of a bearing ring 1 with notches 2 being on a dividing line for splitting, and pressing the bearing ring 1 between upper and lower molds 4 and 5 along the dividing line on which the notches 2 are provided, the raceway surface 1a of the bearing ring 1 is ground in the shape of an ellipsoid which major diameter lies on the dividing line, and in that natural splitting is then effected.