The bearing ring comprises a retaining ring and a retaining ring, the retaining ring is a two-lobe structure and the outer circle of the retaining ring is provided with a first step; the retaining ring is an integral structure, The inner circle of the retaining ring is provided with a second step, which cooperates with the second step. The utility model has the advantages that the retaining ring and the retaining ring can bear greater axial force, are more safe and reliable to be positioned, and are easy to handle.
A notch portion is formed in a plurality of portions in the circumferential direction of the cylindrical portion so as to be recessed toward the stopper portion in the axial direction, respectively, than the front end edge of the cylindrical portion. And a protruded portion protruding toward the opposite side of the retainer portion in the radial direction than the cylindrical portion is provided at a portion closer to the stopper portion than the bottom edge of the cutout portion. Each of these protrusions serves as a stopper preventing portion for preventing the stopper portion from falling off from the mating member to which the crotch portion is attached. In this way, it is possible to realize a structure in which the durability of the backup ring portion in the low-rigidity state and the manufacturing cost can be reduced at the same time.