Wheel Bearing Apparatus

A wheel bearing apparatus comprising:

• an outer member integrally formed, on its outer circumference, with a body mounting flange to be mounted on a knuckle, the outer member inner circumference includes double row outer raceway surfaces;
• an inner member, includes a wheel hub, the inner member outer circumferences include double row inner raceway surfaces opposite to the double row outer raceway surfaces, the wheel hub is integrally formed on its one end with a wheel mounting flange, a cylindrical portion axially extends from the wheel mounting flange;
• double row rolling elements are contained between the inner raceway surfaces of the inner member and outer raceway surfaces of the outer member, via cages;
• a cylindrical pilot portion, adapted to be fit into the knuckle, is formed on an inner-side end of the outer member, the pilot portion includes two guiding portions, a first guiding portion form at the side of inner-side end face of the outer member and a second guiding portion form at the side of the body mounting flange of the outer member;
• a fitting width (A) of the first guiding portion with the knuckle is set larger than a fitting width (B) of the second guiding portion with the knuckle (A>B);
• an outer diameter (D1) of the first guiding portion is set smaller than an outer diameter (D2) of the second guiding portion (D1<D2);
• and
• a seal ring, adapted to elastically contact the inner circumference of the knuckle, is arranged on either one of the first guiding portion or the second guiding portion.