Wheel bearing apparatus

A wheel bearing apparatus comprising:

• an outer member integrally formed with a body mounting flange on its outer circumference, the body mounting flange adapted to be mounted on a knuckle of a suspension apparatus, the outer member inner circumference includes double row outer raceway surfaces;
• an inner member includes double row inner raceway surfaces, a wheel hub and at least one inner ring, the wheel hub is integrally formed with a wheel mounting flange on its one end, a cylindrical portion axially extends from the wheel mounting flange, the at least one inner ring is press-fit onto the cylindrical portion of the wheel hub via a predetermined interference, the at least one inner ring outer circumference is formed with one of the double row inner raceway surfaces that corresponds to one of the double row outer raceway surfaces of the outer member;
• double row rolling elements are freely rollably contained between the inner and outer raceway surfaces of the inner and outer members, via cages;
• a hardened ring-shaped gear member is mounted on an end of the cylindrical portion of the wheel hub, the gear member is formed with a gear portion on its outer circumference and with a splined portion on its inner circumference, the splined portion engages a hub-splined portion formed on the outer circumference of the cylindrical portion of the wheel hub;
• a contacting surface of the gear member and a contacting surface of the at least one inner ring that abut against each other are ground to provide a desired roughness on the contacting surfaces to enable close contact and frictional resistance between the contacting surfaces to reduce torque on the splined portion;
• and
• the at least one inner ring is axially immovably secured to the wheel hub under a condition where a predetermined amount of a bearing pre-stress is applied to the at least one inner ring, via the gear member.