Wheel bearing apparatus incorporated with a wheel speed detecting apparatus

A wheel bearing apparatus with a wheel speed detecting apparatus comprising:

• an outer member having an integrally formed body mounting flange, double row outer raceway surfaces formed on the inner circumferential surface of the outer member;
• an inner member including a wheel hub having an integrally formed wheel mounting flange at one end and a cylindrical portion axially extending from the wheel mount flange and an inner ring fit onto the cylindrical portion of the wheel hub;
• double row inner raceway surfaces formed on the outer circumferential surfaces of the wheel hub and inner ring, respectively, positioned opposite to the double row outer raceway surfaces;
• double row rolling elements arranged between the outer and inner raceway surfaces;
• an encoder mounted on the outer circumferential surface of the inner ring;
• and
• a sensor holder arranged on an end of the outer member opposite to the encoder, said sensor holder including an annular fitting member and a holding portion formed from synthetic resin molded integrally with the annular fitting member and a wheel speed detecting sensor embedded in said resin and positioned opposite to the encoder via a predetermined gap, said encoder has its characteristics varying alternately and equidistantly along its circumferential direction;
• a seal arranged at an inboard side of the encoder, said seal including a first sealing plate and a second sealing plate fit, respectively, on the annular fitting member and the inner ring and arranged opposite to one another, and a tip end of the annular fitting member engaging the holding portion.