| 摘要 |
PROBLEM TO BE SOLVED: To provide a bearing device for a wheel and its manufacturing method achieving cost reduction by reducing the number of processing man-hours and material loss and elongating the service life of a bearing. SOLUTION: An outer member 2 is forged from a round bar material leaving a predetermined turning allowance. In this forging process, groove parts 18 corresponding to double row outer rolling surfaces 2a are formed to have an arcuate cross section. In the tangential direction of the groove parts 18, counterbores 15, 16 are formed to have a tapered shape, and then, the double row outer rolling surfaces 2a are formed to have predetermined shape dimension by turning or grinding without processing part of the counterbores 15, 16. Thus, with respect to the tangential direction of the outer rolling surfaces 2a and balls 3, the arcuate faces of the groove parts 18 and the outer rolling surfaces 2a are formed concentrically. As a result, the cutting allowance becomes uniform, so as to suppress cutting processing amount and reduce the number of processing man-hours. COPYRIGHT: (C)2008,JPO&INPIT
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