Abstract: A hub unit bearing apparatus for a vehicle, adapted to rotatably support a constant velocity joint and a wheel on a vehicle body and to connect them to each other, comprises an outer race attached to a vehicle body, a shaft extending from a constant velocity joint and having a first reduced diameter portion at its free end, a cylindrical hub fitted on the first reduced diameter portion and having one end which is near the constant velocity joint and on which a second reduced diameter portion is formed, an inner race fitted on the second reduced diameter portion and cooperating with the outer race via rolling members to construct a bearing, a first nut threaded on the second reduced diameter portion so as to protrude from an end face of the second reduced diameter portion axially and urging the inner race against a body portion of the hub, and a second nut threaded on the second reduced diameter portion and urging the hub, inner race and first nut against the constant velocity joint.

Abstract: A pulse rotor is externally supported and secured on a cylindrical face section formed on a hub. The amount by which this pulse rotor projects from an outer ring member is regulated when the pulse rotor is fitted onto the cylindrical face section for supporting. A sensor is provided on the inside of a cover which covers the open end section of the outer ring member. The axial positional relationship between the cover and the outer ring member is uniformly maintained by means of an engaging projection formed on the radially outer peripheral surface of the cover. The distance between the axial end surface of the sensor and the axial end surface of the outer ring member is controlled to a specified value by this means. As a result, the distance between the pulse rotor and the sensor is precisely controlled.