| 摘要 |
PURPOSE:To enable uniform and simultaneous heating of plural raceway grooves with good working efficiency by disposing torus high-frequency induction heating coils into the respective plural raceway grooves provided on the inside circumferential surface of a cylindrical member with the eccentricity from the respective raceway grooves. CONSTITUTION:Torus high-frequency induction heating coils 4a, 4b of the same diameter connected in series to each other are used so as to meet the two raceway grooves 2, 3 formed on the inside circumferential surface 1a of a cylindrical member 1 fixed on a jig 12 and the outside size L1 thereof is made slightly smaller than the bore size L2 in the small diameter part 7 of said member 1. The above-mentioned coils 4a, 4b are first inserted into the respective chain line positions and thereafter the coils are horizontally moved in an arrow B direction and are disposed in the positions of the solid lines eccentric from the grooves 2, 3. High-frequency large current is then supplied to the coils 4a, 4b from a high- frequency power source 11 via leads 10 while the member 1 is rotated relatively with the coils 4a, 4b by the jig 12. After the circumferential surface parts of the grooves 2, 3 are thereby heated to a prescribed temp., the grooves are hardened by ejection cooling. |
