| 摘要 |
PURPOSE:To prevent excess load from being locally concentrated on a hub, and in particular any stress from being concentrated on a joint part between the hub and a wheel main body by forming a plurality of reinforcing rib pieces on at least one of a bearing cylinder part and a boss part. CONSTITUTION:A hub H comprises a hollow cylindrical shaft cylinder part 1, and a wheel support part 2 integrally and radially extending from an axial one side of the cylinder part 1. A plurality of reinforcing pieces 7 are integrally projected on the internal peripheral surface of the cylinder part 1 peripherally spaced in an equal interval inwardly radially for reinforcing a connection between ball bearings 3, 3 of the cylinder part 1. A boss part 15 of the wheel main body W is formed into a channel shape cross section with an internal peripheral side cylindrical part 15a which forms a boss hole and portions 15b, 15c to be clamped extending radially from one end of the cylindrical part 15a, and further adapted to have a partition wall 15d integrally provided therewith between the internal and external, peripheral cylindrical parts 15a, 15c for reinforcing the boss 15. |
