| 摘要 |
PROBLEM TO BE SOLVED: To provide a bearing unit for supporting a wheel securing a long lifetime by increasing stiffness while achieving cost reduction, miniaturization and weight reduction. SOLUTION: This bearing unit for supporting wheel is provided with a stationary ring 2, a rotation ring 4, and rolling elements 20. The rotation ring is provided with a hub 10 and an inner ring structure body 12. An inner ring structure body is integrated by caulking the hub. The inner ring structure body has a chamfer part 12a formed at an inner diameter end part of an inside of a vehicle body. The hub is provided with a caulking part 10e having an end part of the inside of the vehicle body extended in a cylindrical shape from an end surface 12i of the inner ring structure body under a condition before caulking in order to gripping the inner ring structure body after caulking. A diameter dimension of an inner circumference part after caulking at the inside of a vehicle body e2 is set larger than that at an outside of the vehicle body e1 with putting a boundary at a step 10g. The step is positioned along a circumference at any position of a circumference area between a position p1 in a same phase with a shape start point p3 of the chamfer part of the inner ring structure body in an axial direction, and a position p2 to be an inner diameter end part of the caulking part after caulking. COPYRIGHT: (C)2009,JPO&INPIT
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