Patent ID: 8047721

Claim:
A vehicle wheel bearing apparatus comprising: an outer member formed, on its outer circumference, with a body mounting flange to be mounted on a suspension of a vehicle and on its inner circumference with double row outer raceway surfaces; an inner member including a wheel hub formed, on its one end, with a wheel mounting flange and on its outer circumference with a cylindrical portion, an outer circumference of the wheel mounting flange is formed with a circumferential stepped recess, an inner ring or an outer joint member of a constant velocity universal joint press-fit onto the wheel hub and formed, on its outer circumference, with inner raceway surfaces arranged opposite to the double row outer raceway surfaces; double row rolling elements freely rollably held by cages between the outer and inner raceway surfaces of the outer and inner members; seals mounted within annular openings formed between the outer and the inner members; a backup seal arranged radially outward of an outer side seal of said seals; the backup seal comprises a sealing lip inclined radially outward toward the outer side; and the sealing lip slidingly contacts an annular metal member, said annular metal member pressed from a steel sheet having preservation properties and is bolted on a side face of the wheel mounting flange of the inner side, the annular metal member is formed, on its outer circumference, with an axially extending cylindrical portion to be fit into the stepped recess on the outer circumference of the wheel mounting flange.