Patent ID: 7047645

Claim:
A method of forming a bearing unit for a wheel, comprising: providing a rotary ring having a mounting flange provided at an outer periphery of the rotary ring for fixedly connecting a rotary body for braking and a wheel to a mounting surface, said mounting flange having plural mounting holes communicating between one side surface and another side surface and having a concave portion all over the periphery thereof at an intermediate portion in a circumferential direction thereof, wherein each of the mounting holes opens within the concave portion at one end thereof in the axial direction; inserting studs into said mounting holes, and press-fitting respective base portions thereof into the plural mounting holes; forming a mounting surface on said mounting flange wherein said mounting surface defines a flat surface with a substantially constant surface precision, wherein said forming is performed after the rotary side raceway surface is heat-treated, and after the base portion of the studs are fixedly press-fitted into the mounting holes, but before a roller member is mounted.