Patent ID: 6796714
Filing Date: 2004-09-28
Classification: B60B,F16C

Abstract:
A rolling-bearing unit for wheel support comprising:an outer-race having an inner peripheral surface formed with a double row of tapered and concave-shaped outer-ring raceways thereon, a hub comprising a hub body having an outer peripheral surface, an outside end portion, a middle portion and an inside end portion, the outer peripheral surface at the middle portion formed with an outside inner-ring raceway directly thereon or on an inner race thereon, and a separate inner-race having an inside end, an outside end and an outer peripheral surface formed with an inside inner-ring raceway thereon to have a diameter which becomes larger toward the inside end thereof, and a plurality of tapered rollers provided between the inner-ring raceways and the outer-ring raceways respectively, the inside end of the separate inner-race formed with a large-diameter-side collar section with a side surface, the outer peripheral surface at the outside end portion of the hub body formed with a flange for supporting a wheel, the inside end portion of the hub body formed with a cylindrical section, the outer peripheral surface at least the inner end portion of the hub body formed with a support-step section which the separate inner-race is fitted onto, the cylindrical section plastically deformed radially outward to form a crimped section, the support-step section having an outside end portion formed with a step surface, the outside and inside ends of the separate inner-race having an end surface, respectively, the separate inner-race fixed and supported by the support-step section such that the end surface of the outside end of the separate inner-race is abutted to the step surface, and that the end surface of the inner end of the separate inner-race is retained by the crimped section at a contact area, and the inner-ring raceway of the separate inner-race connected to the side surface of the large-diameter-side collar section through a connecting portion which is provided with a grinding-relief groove having a bottom with a diameter defined thereby, and wherein the contact area between the end surface of the inside end of the separate inner ring and the crimped section has a maximum diameter smaller than the diameter defined by the bottom of the grinding-relief groove.