| 摘要 |
PROBLEM TO BE SOLVED: To provide a bearing device for a wheel which enhances reliability by improving flange deflection accuracy of a wheel mounting flange while maintaining strength/rigidity of the wheel mounting flange, and increasing a slip torque of a hub bolt. SOLUTION: In the bearing device for the wheel, a bolt insertion hole 6a is pierced at an equally arranged position in a circumferential direction of the wheel mounting flange 6, a knurl 7a is formed at the neck part of the hub bolt 7 which joints the wheel, and the hub bolt 7 is pressed and fixed in the bolt insertion hole 6a. In the device, chamfers 10, 11 are formed at the opening part of the bolt insertion hole 6a, the outer side chamfer 11 out of these chamfers is composed of two-stepped corner chamfers 11a, 11b with predetermined tilt anglesβ,γ, the tilt angleβof the inside chamfer 11a is set within 25-35°with respect to an inner peripheral surface of the bolt insertion hole 6a, and the outside chamfer 11b is set within 25-35°with respect to an outer surface 6b of the wheel mounting flange 6. COPYRIGHT: (C)2009,JPO&INPIT
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