Patent ID: 6942393

Claim:
A wheel bearing device, comprising: an outer member formed with double-row outer races on an inner periphery thereof; an inner member including a wheel hub having a flange for attachment of a wheel and an fitting member fitted to one of an inner-periphery or an outer periphery of the wheel hub, said inner member being formed with double-row inner races on an outer periphery thereof, the member that is located outside out of the wheel hub and the fitting member being provided with a hardened irregular portion, the other member that is located inside out of the wheel hub and the fitting member being expanded radially outward by plastic deformation to be engaged with the irregular portion, so that the wheel hub and the fitting member are coupled with each other; and double-row rolling elements interposed between the outer races and the inner races, wherein a ratio of an inner diameter ΦdA before plastic deformation at a plastic deformation portion of the member that is located inside and an inner diameter ΦdB after the plastic deformation (Δ=ΦdB/ΦdA) is equal to 1.05 or more.