| 摘要 |
<p>[PROBLEMS] To provide a bearing device for a wheel, in which contradictory problems of reduction in weight and size and increased rigidity of the device are simultaneously solved and whose strength and durability are increased. [MEANS FOR SOLVING THE PROBLEMS] In this bearing device for the wheel, hub bolts (6a) are implanted in the wheel mounting flange (6) of a hub wheel (4) at regular intervals in the circumferential direction. The pitch circle diameter of outer side rolling element (3) groups is set larger than that of inner side rolling element groups, the outer diameters of rolling elements (3) are set to be the same, and the quantity of the outer side rolling element (3) groups is set larger than that of the inner side rolling element groups. Thick wall ribs (17) are formed on the inner side-face of the wheel mounting flange (6). Each of the ribs (17) comprises a straight part (17a) radially extending from the base part (6c) of the wheel mounting flange (6) and a tip round part (17b). The tip round part (17b) is set to such a predetermined radius of curvature (r) that has a center at the axis (O) of the hub bolt (6a) and its outer periphery is approximately aligned with the outer periphery of the wheel mounting flange (6).</p> |
