| 摘要 |
<p>PROBLEM TO BE SOLVED: To simultaneously apply uniform hardening to the whole circumferences of respective external surfaces of pin parts of a crankshaft used for a multiple cylinder engine. SOLUTION: Heating coils 21, 22, 23, 24 sitting astride of pin parts 11, 12, 13, 14 are connected to the secondary sides of current transformers 41, 42, 43, 44, respectively. The primary sides of the current transformers 41, 42, 43, 44 are connected to a high-frequency power source 50 via Slidac-type high-frequency voltage regulators 81, 82, 83, 84, respectively. The Slidac-type high-frequency voltage regulators 81, 82, 83, 84 are controlled on the basis of the turning angle phase change of the pin parts 11, 12, 13, 14 attendant on the rotation of the crankshaft 10.</p> |
