Rolling bearing unit for wheel

摘要

A rolling bearing unit for a wheel includes an outer ring member having a flange portion formed on its outer periphery and fitted to a vehicle body-side member, an inner ring member rotatably fitted in the outer ring member, and double-row rolling elements arranged between the outer ring member and the inner ring member. The flange portion includes a first flange portion formed on the upper-side portion of the outer periphery, and a second flange portion and a third flange portion formed on the lower-side portion of the outer periphery. Each of the first, second and third flange portion has a bolt-hole used to fit the outer ring member to the vehicle body-side member. The first flange portion is formed in such a manner that the bolt-hole thereof is positioned on the vertical line that passes through the rotational center of the outer ring member.