Patent ID: 8425124

Claim:
A vehicle bearing device comprising: a hub spindle that has a flange to which a wheel is fitted, a large rib portion, an inner raceway surface, a large-diameter portion, an intermediate-diameter portion that is smaller in outside diameter than the large-diameter portion, and a small-diameter portion that is smaller in outside diameter than the intermediate-diameter portion, which are arranged in this order from one axial end portion of an outer periphery of the hub spindle toward the other axial end portion of the outer periphery; an inner ring that has an inner ring raceway surface on its outer periphery, and that is fitted to an outer periphery of the small-diameter portion of the hub spindle; an outer ring that has two outer ring raceway surfaces on its inner periphery, and that is fixed to a vehicle body side-member so as to be coaxial with the hub spindle, on a radially outer side of the hub spindle and the inner ring; a plurality of tapered rollers rollably arranged between the two outer ring raceway surfaces and the inner raceway surface and inner ring raceway surface; an annular pulsar ring that is fitted to an outer periphery of the intermediate-diameter portion of the hub spindle, and that rotates together with the hub spindle; and a sensor that is fitted to the outer ring, and that is used to detect rotation of the pulsar ring, wherein the large rib portion of the hub spindle has a large rib surface with which large-diameter-side end faces of the tapered rollers are in sliding contact, an annular grinding undercut portion, which is a recess in sectional view, is formed, through turning, at each of at least two of a large rib surface-side end portion of the inner raceway surface, a large-diameter portion-side end portion of the inner raceway surface, and a large-diameter portion side end portion of the outer periphery of the intermediate-diameter portion, and the grinding undercut portions are formed in the same shape.