Patent ID: 7252436

Claim:
A roller bearing cage; comprising a cage made up of a pair of annular members arranged in a way spaced axially apart from each other and extended circumferentially in parallel with each other, pillars integral with the annular members and positioned at regular intervals around circular surfaces of the cage to provide pockets between any two adjacent pillars, and rollers received in the pockets, one to each pocket; wherein a circular outside surface of the cage is made even across an overall length in the axial direction of the cage while a circular inside surface of the cage is made circularly inside recessed at a middle portion in an axial direction of the cage to provide a configuration of a concaved surface, wherein the concaved surface is made around the circular inside surface of the cage in such a manner that a diametral dimension between diametrically opposite bottoms of the concaved surfaces is larger than a diametral dimension of a pitch circle of the cage, and wherein the pillars each include axially opposite thick portions and a portion lying between the axially opposite thick portions which gradually decrease in thickness on sides thereof, so that guide surfaces against which the associated roller is carried for rotation is constituted in part by the thick portions and in part by the portion lying between the thick portions.