| 摘要 |
PROBLEM TO BE SOLVED: To provide a bearing device for a wheel capable of extending the life of a bearing by solving conflicting problems such as weight reduction, compactness and high rigidity. SOLUTION: The bearing device for the wheel is equipped with a hub wheel 4 integrally having a wheel-mounting flange 6 at one end part and a group of double-row balls 3, 3. The pitch circle diameter PCDo of the group of balls 3 at the outer side among the group of double-row balls 3, 3 is set to be larger than the pitch circle diameter PCDi of the group of balls 3 at the inner side. A petal-shaped rib 18 of a wall thickness part is formed on a portion where a hub bolt 6a of the side surface of the inner side at the wheel-mounting flange 6 is press-fitted and a circular hole 6b is formed between the ribs 18 by punching work. Since the wall thickness t0 between the circular hole 6b and the outer peripheral surface 6d of the wheel-mounting flange 6 is set to be at least 5 mm, strength and rigidity are secured, the circular hole 6b having the maximum diameter can be formed while suppressing a sink due to the punching work, and the weight of the hub wheel 4 can be reduced. COPYRIGHT: (C)2008,JPO&INPIT
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