Patent ID: 8132967

Claim:
A wheel bearing apparatus with an incorporated wheel speed detecting apparatus comprising: an outer member having double row outer raceway surfaces formed on its inner circumferential surface; an inner member including a wheel hub with an integrally formed wheel mounting flange at one end and a cylindrical portion axially extending from the wheel mounting flange, an inner ring fit onto the cylindrical portion of the wheel hub, double row inner raceway surfaces, opposite to the double row outer raceway surfaces, formed on the outer circumferential surfaces of the wheel hub and inner ring, respectively; an inboard side end of said outer member is positioned outboard of an inboard side end of said inner ring; double row rolling elements arranged between the outer and inner raceway surfaces; an encoder mounted on the outer circumferential surface of the inner ring; an annular sensor holder arranged on the end of the outer member opposite to the encoder, said sensor holder including an annular fitting member and a holding member, the annular fitting member comprises a cylindrical fitting portion press-fitted on the outer circumferential surface of the outer member, a flange portion extending radially inward from the fitting portion, a conical portion extending axially inboard from the flange portion, and a cylindrical portion axially extending from the tip of the conical portion; a wheel rotation speed detecting sensor integrally molded with the sensor holder and arranged opposite to the encoder via a predetermined radial gap; the encoder has an annular ring configuration with its characteristics alternately and equidistantly varying along its circumferential direction; a seal is arranged at the inboard side of the wheel rotation speed detecting sensor, said seal including a first annular sealing plate fit on an inner circumferential surface of the axially extending portion of the annular fitting member of the sensor holder, the seal including a second annular sealing plate mounted on the inner ring, and said first and second annular plates oppose each other so that the seal is sandwiched between the axially extending portion of the annular fitting member of the sensor holder and the inner ring.