Patent ID: 7650696

Claim:
A method for manufacturing a wheel supporting bearing unit comprising: a hub comprising: a hub main body having an axially outboard portion, an axially intermediate portion, and an axially inboard portion; a mounting flange which is provided integrally on an outer circumferential surface of the axially outboard portion of the hub main body and to which a wheel and a brake rotary member are mounted; an axially outboard inner ring raceway which is formed directly on an outer circumferential surface of the axially intermediate portion of the hub main body; and an inner ring which is fitted on a cylindrical surface portion formed an outer circumferential surface of the axially inward portion of the hub main body; an axially inboard inner ring raceway formed on the inner ring, wherein the axially outboard inner ring raceway and the axially inboard inner ring raceway make up a double row inner ring raceway; an outer ring having a double row outer ring raceway on an inner circumferential surface thereof; and a plurality of rolling elements which are provided between the double row outer ring raceway and each of the inner ring raceways, respectively, the method for manufacturing the wheel supporting bearing unit comprising the steps of: (A) grinding a supporting surface provided on an axial end face of an inner ring supporting member, in a state of mounting the inner ring supporting member on a spindle adapted to be driven to rotate, while rotating the inner ring supporting member together with the spindle, to thereby improve perpendicularity of the supporting surface relative to a rotational center axis of the spindle, and grinding at least the axially inboard inner ring raceway formed on an outer circumferential surface of the inner ring and a cylindrical inner circumferential surface of the inner ring, respectively, in a state of abutting an axially end face of the inner ring with the supporting surface, while rotating the inner ring together with the spindle and the inner ring supporting member, or (B) grinding a supporting surface provided on an axial end face of a hub supporting member, in a state of mounting the hub supporting member on the spindle adapted to be driven to rotate, while rotating the hub supporting member together with the spindle, to thereby improve perpendicularity of the supporting surface relative to a rotational center axis of the spindle, and grinding at least the axially outboard inner ring raceway and the cylindrical surface portion onto which the inner ring is fitted, respectively, in a state of abutting an axially outboard surface of the mounting flange with the supporting surface, while rotating the hub main body together with the spindle and the hub supporting member.