| 摘要 |
A bearing apparatus for a wheel of vehicle which can solve the antinomic problems of reducing the weight and of increasing the rigidity of the bearing apparatus is provided. According to the present invention there is provided a bearing apparatus for a wheel of vehicle comprising an outer member (2), an inner member (1) and double row groups of characterized in that a pitch circle diameter (PCDo) of the ball group of the outer side is larger than a pitch circle diameter (PCDi) of the ball group of the inner side, and that ribs (17) are formed on a surface of the inner side of the wheel mounting flange (6), each rib (17) being formed by an outline including straight portions (17a) radially extending outward from the base of the wheel mounting flange (6) and a rounded tip portion (17b) having a predetermined radius of curvature (r) centered on the axial center (O) of hub bolt (6a) and substantially corresponding to a distance between the axial center (O) and the outermost periphery of the wheel mounting flange (6). |
