Patent ID: 8157453

Claim:
A bearing device for a wheel, comprising: a hub wheel; an inner ring fitted onto the hub wheel; an outer ring; a plurality of outboard side tapered rollers provided between the outer ring and the hub wheel; a plurality of inboard side tapered rollers provided between the outer ring and the inner ring; and an outboard side retainer and an inboard side retainer having pockets retaining the outboard side tapered rollers and the inboard side tapered rollers, respectively, with a rib portion being provided on the outboard side of an inner peripheral surface of the outer ring, wherein for each outboard side tapered roller and corresponding pocket of the outboard side retainer, a projection is provided on one of an end surface of the outboard side tapered roller and a surface of the outboard side retainer which opposes the end surface, and a recess is provided in the other of the end surface of the outboard side tapered roller and the surface of the outboard side retainer which opposes the end surface, wherein relative movement in a radial direction is allowed between the outboard side tapered rollers and the outboard side retainer, wherein a diameter of a circumcircle of a row of the outboard side tapered rollers is larger than an inner diameter dimension of the rib portion, wherein for each outboard side tapered roller and corresponding pocket of the outboard side retainer, a clearance is formed between the projection and the recess for allowing radial inward movement of the outboard side tapered roller, and wherein each outboard side tapered roller is arranged such that Y is greater than or equal to X, where Y is a width of the clearance in the radial direction, and X is a difference between a radius of the circumcircle of the row of the outboard side tapered rollers and a radius of the inner diameter dimension of the rib portion.