Patent ID: 7771124

Claim:
A vehicle wheel bearing apparatus comprising: a wheel hub integrally formed with a peripheral wheel mounting flange at one end; a double row rolling bearing, the double row rolling bearing comprising an outer member integrally formed with a peripheral body mounting flange and with double row outer raceway surfaces, said wheel hub formed with one of the inner raceway surfaces of the double row rolling bearing on its outer periphery and with a cylindrical portion axially extending from the one inner raceway surface; an inner member including a separate inner ring press fit onto the axially extending portion, double row rolling elements being freely rotatably contained between said double row outer and inner raceway surfaces, said double row rolling bearing being adapted to receive a predetermined preload; said outer member comprises an outer ring member formed with one of the outer raceway surfaces on its inner periphery and a separate outer ring formed with the other of the outer raceway surfaces on its inner periphery; and an electrostrictive element, arranged at an abutting portion between said outer ring member and the outer ring, being extended or contracted by applying a predetermined voltage to the electrostrictive element based on an output signal from a steering angle sensor in order to extend the electrostrictive element.