METHOD FOR INDUCTION-HARDENING GEAR

摘要

PURPOSE:To increase the toughness of the roots of the teeth of a gear and to improve the fatigue strength by forming triangular projections on the inside of a circular high-frequency induction heating coil so that the shape of the inside of the coil corresponds to the shape of the outside of the gear and by hardening the gear along the outline. CONSTITUTION:Triangular projections 12 formed on the inside of a circular high-frequency induction heating coil 11 are put in the spaces among the bottoms 2 and the sides 3 of the teeth of a gear and the inside of the coil 11. The gear is induction-heated so as to make the temp. of the bottoms 2 higher than the temp. of the tips 1. A coolant is then spouted from coolant nozzles 14 fixed on the inside of the coil 11 toward the gear along the surfaces of the projections 12 to harden the gear along the outline.