To provide a bearing device for a wheel, which improves the resistance to creep of an inner ring fitting surface of a hub ring, and improves the durability of the hub ring and an inner ring secured to the hub by caulking.
In the bearing device for the wheel, the inner ring 5 pressed in a minor diameter stepped portion 1b of the hub ring 1, having a major flange 5b at the major diameter side of an inside rolling surface 5a, is secured by a caulking portion 8. An annular recess 13 is formed in an end surface of the minor diameter portion 1b, and the depth b is set 5 mm or less from an end surface 5d of the inner ring 5. A predetermined hardened layer 12 is formed by induction hardening from a base to the minor diameter stepped portion 1b of the wheel mounting flange 3. An end position P of the inner side of the hardened layer 12 is set within the limits from an edge PO of the chamfered portion 5e of the inner ring 5 to the position corresponding to a height a of the major flange 5b, which prevents the fretting abrasion at the fitting surface to improve the durability and can prevent the major flange 5b of the inner ring 5 from deforming owing to the caulking process.
COPYRIGHT: (C)2008,JPO&INPIT
KATO HIROYA
FUJIMURA HIROSHI
HIRAI ISAO
FUKADA KIKUO
