| 摘要 |
PURPOSE: To facilitate mechanical machining by performing mechanical machining when a gear blank is comparatively soft and performing a contour hardening process after performing a prehardening process as a novel method for forming a contour hardened gear. CONSTITUTION: Initially, an uncut gear blank is softened by a heat treatment process to provide a relatively soft level of hardness throughout. Then, the softened gear blank is machined to form a plurality of gear teeth 12. A machined gear 11 is next subjected to a prehardening process, wherein the surfaces of the gear teeth 12 and an outer region 13 of a core part are hardened to a predetermined intermediate level of hardness. Finally, the prehardened gear 11 is subjected to a contour hardening process to harden a profile part 15 of the surface of each gear tooth 12 furthermore. The outer region 13 of the core part of the gear 11 remains at the intermediate hardness level, while an inner region 14 of the core part remains at a relatively soft level. |
