Patent ID: 9404531
Filing Date: 2016-08-02
CPC Classification: B60B,F16C

Claim Text:
1. A bearing apparatus for a wheel, comprising: an outer member having multiple rows of annular outer raceway surfaces on an inner circumferential surface; an inner member having multiple rows of annular inner raceway surfaces opposing said outer raceway surfaces; and a rolling element in freely rolling contact with said outer raceway surface and said inner raceway surface; said inner member including a flanged member that is made of steel and has a wheel attachment flange formed thereon, said flanged member having: a portion hardened to attain at least 50 HRC as a result of quench hardening, a non-hardened portion, and a residual compressive stress in a range from at least 50 MPa to at most 500 MPa remaining in a surface of said non-hardened portion as a result of a thermal refining step followed by a turning step and/or a broaching step, wherein: the thermal refining step includes a quenching step and a tempering step, the tempering step is performed at a temperature from at least 400° C. to at most 700° C., said flanged member has an insertion hole for insertion of another member formed in a region including a central axis of a raceway of said rolling element, and a sidewall of said insertion hole is included in said non-hardened portion where the residual compressive stress in a range from at least 50 MPa to at most 500 MPa remains in the surface of said non-hardened portion.