| 摘要 |
PROBLEM TO BE SOLVED: To provide a heat treatment method for an outward member of a wheel bearing device wherein a stable hardened layer can be formed with induction hardening. SOLUTION: In the heat treatment method for the outward member 2 of the wheel bearing device, a heating part 21 is provided which has integrated annular high frequency heating coils 21a, 21b corresponding to double row outside rolling surfaces 2a, 2b, where a diameter difference between the outer diameters is set to be the same as each of groove diameter differences and an outer diameter Dc of the high frequency heating coil 21b corresponding to the outside rolling surface 2b on the inner side is set to be smaller than an inner diameter ds of a shoulder portion 18. The heating part 21 is inserted through the outer side of the outward member 2, and then the high frequency heating coils 21a, 21b are opposed to the double row outside rolling surfaces 2a, 2b in the state that the axial center of the heating part 21 corresponds to that of the outward member 2. The high frequency heating coils 21a, 21b are energized to rotate the heating part 21 around the axial center, and cooling water 25 is jetted from a cooling nozzle 22 for concurrent hardening to form a predetermined hardened layer 14. COPYRIGHT: (C)2008,JPO&INPIT
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