Wheel Bearing Apparatus For A Vehicle

A vehicle wheel bearing apparatus comprising:

• an outer member integrally formed with double row outer raceway surfaces on its inner circumference;
• an inner member including a wheel hub and at least one inner ring, the wheel hub integrally formed at one end with a wheel mounting flange and with a cylindrical portion on its other end, the inner ring being press fit onto the cylindrical portion of the wheel hub, the inner member formed with double row inner raceway surfaces arranged opposite to the double row outer raceway surfaces;
• double row rolling elements are rollably contained between the double row inner and outer raceway surfaces of the inner member and the outer member;
• a constant velocity universal joint connected to the wheel hub;
• the inner ring is axially immovably secured relative to the wheel hub by a caulked portion, the caulked portion is formed by plastically deforming an end of the cylindrical portion radially outward;
• an outer joint member of the constant velocity universal joint includes an integrally formed cup shaped mouth portion, a shoulder portion forming a bottom of the mouth portion, and a stem portion fit into the wheel hub to transmit torque between each other via serrations, and the wheel hub and the outer joint member are axially separably connected, and the shoulder portion abuts against the caulked portion;
• a cap is interposed between the caulked portion and the shoulder portion, the cap is press-formed from a steel plate and has a surface roughness of 0.63 Ra or less.