| 摘要 |
PROBLEM TO BE SOLVED: To provide a bearing device for a wheel capable of solving problems of durability, high accuracy, and reduction of the cost, and capable of achieving the long service life of a bearing. SOLUTION: In the bearing device for the wheel wherein a diameter PCDo of a pitch circle of a group of balls 3 on an outer side is set to be larger than a diameter PCDi of a pitch circle of a group of balls 3 on an inner side, an outer member 2 is formed by medium or high carbon steel including 0.40-0.80 wt.% of carbon, and a prescribed hard layer 13 is formed on double-rows of outer rolling surfaces 2a and 2b by induction hardening, and formation of the hard layer 13 in shoulder parts 16 and 17 between the double-rows of the outer rolling surfaces 2a and 2b is determined in accordance with a distance L between the double-rows of the outer rolling surfaces 2a and 2b. When the distance L is 14 mm or more, the hard layer 13 is stopped by the double-rows of the outer rolling surfaces 2a and 2b, and the shoulder parts 16 and 17 are non-hardened parts, therefore, the heat treatment man-hour is reduced, and the cost is reduced, and heat treatment deformation is restrained, and high accuracy can be achieved. COPYRIGHT: (C)2008,JPO&INPIT
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