Patent ID: 8764299

Claim:
A wheel bearing apparatus incorporating a rotational speed detecting apparatus comprising: an outer member integrally formed with double row outer raceway surfaces on its inner circumference; an inner member includes a wheel hub and at least one inner ring, the wheel hub is integrally formed on one end with a wheel mounting flange, a cylindrical portion axially extends from the wheel mounting flange, the inner ring is press fit onto the cylindrical portion of the wheel hub, the inner member outer circumference includes double row inner raceway surfaces opposing the double row outer raceway surfaces; double row rolling elements are contained between the outer raceway surfaces and inner raceway surfaces of the outer member and the inner member; a pulser ring is adapted to be fit onto the outer circumference of the inner ring and secured to it, the pulser ring has a magnetic characteristic that alternately and equidistantly varies along a circumferential direction; a bottomed cylindrical sensor cap, formed of synthetic resin by injection molding and having a continuous substantially planar inner surface positioned adjacent to the pulser ring, is fit onto the inner-side end of the outer member; a mounting portion, formed on the sensor cap, axially projects from the sensor cap at a radially outer position; a sensor unit is mounted on the mounting portion at a position corresponding to the pulser ring; a rotational speed sensor, embedded in the sensor unit, is arranged opposite to the pulser ring, via a predetermined axial air gap; and an axially extending through bore is formed in the mounting portion, a bottomed cylindrical sensor receptacle having a cylindrical wall with an open end and a closed end is integrally molded with the through bore, the sensor receptacle is press-formed from a non-magnetic steel sheet, the closed end of the sensor receptacle is arranged opposite to the pulser ring via a predetermined axial gap, the closed end of the sensor receptacle is positioned in alignment to be substantially flush with the sensor cap planar inner surface and the sensor unit is detachably secured to the sensor receptacle.