| 摘要 |
PROBLEM TO BE SOLVED: To provide a bearing device for driving wheels reduced in weight without changing the shape and dimensions of a wheel mounting flange and without deteriorating runout on face and enhanced in strength and durability of a hub ring under a rotary bending condition. SOLUTION: The bearing device for wheels is a unit formed of the hub ring 1, a double row rolling bearing 2 and a constant velocity universal joint 3. The hub ring 1 has a hardened layer S formed on a surface corresponding to sealing land of at least a roller bearing 2 of a heat-treated hub ring unit, an external raceway 28 on the outer board side, and a small diameter step part 34 fitted with an inner ring 24 in an outer fitting manner. A protrusion 35, provided in either an outer diameter surface of a shaft 12 of an external coupling member 5 or an inner diameter surface 37 of a hole 22 of the hub ring 1 and extending in an axial direction is pressed into the other. A protrusion-recess fitting structure brings the protrusion 35 and a recess 36 in close contact with each other in the entire fitted contact region 38 by forming the recess 36 on the other closely fitted with the protrusion 35 by the protrusion 35. COPYRIGHT: (C)2009,JPO&INPIT
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