Patent ID: 7044647

Claim:
A wheel bearing device comprising: an outer member formed with double-row outer races on an inner periphery thereof; an inner member formed with double-row inner races on an outer periphery thereof, the inner member including a wheel hub with a flange for attachment of a wheel and a fitting member fitted to one of an inner periphery or an outer periphery of the wheel hub, one of the wheel hub and the fitting member that is located inside including a plastically deformed portion radially expanded by plastic deformation to be coupled with the other one of the wheel hub and the fitting member that is located outside and an adjacent part adjoining the plastically deformed portion with a different inside diameter than that of the plastically deformed portion; double-row rolling elements interposed between the outer races and the inner races; and stress alleviating means for mitigating stress concentration at an interface part between the plastically deformed portion and the adjacent part of the one that is located inside.