Wheel Bearing Apparatus Provided With A Rotational Speed Detecting Apparatus

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

• an outer member integrally formed with a body mounting flange on its outer circumference, the body mounting flange is to be mounted on a knuckle, outer member inner circumference includes double row outer raceway surfaces;
• an inner member includes a wheel hub and at least one inner ring, 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, the inner ring is press-fit onto the cylindrical portion of the wheel hub, the inner member is formed with double row inner raceway surface on its outer circumference, the double row inner raceway surfaces oppose the double row outer raceway surfaces;
• double row rolling elements are contained between the inner raceway surfaces and outer raceway surfaces of the inner member and outer member;
• a pulser ring is adapted to be fit onto the outer circumference of the inner ring, the pulser ring has a magnetic characteristics alternately and equidistantly varying along its circumferential direction;
• a cup-shaped sensor cap is press-formed from steel sheet and fit onto the inner-side end of the outer member;
• a rotational speed sensor is mounted on the sensor cap at a radially outer position, the rotational speed sensor is arranged opposite to the pulser ring, via a predetermined axial air gap;
• a cup-shaped cap is coated by preserving film, the cup-shaped cap is mounted onto the outer member, the cap is press-formed of non-magnetic steel sheet, the cap further comprises a cylindrical fitting portion, a disk portion, and a bottom portion, the cylindrical fitting portion is press-fit into the inner circumference of the inner-side end of the outer member, the disk portion extends radially inward from the fitting portion and opposes the pulser ring, via a small axial gap, the bottom portion extends from the disk portion, via a bent portion, to cover the inner-side end of the inner member;
• and
• the rotational speed sensor is arranged opposite to the pulser ring, via the disk portion of the cap, where the rotational speed sensor is closely arranged to the disk portion.