| 摘要 |
<p>PROBLEM TO BE SOLVED: To obviate the necessity of the complicated structure in a hardening device and the large size of a part inserted into a bottomed cylindrical work of the hardening device by hardening the inner peripheral surface to near the topmost part of the bottomed cylindrical work, at the time of shift-hardening the inner peripheral surface of the bottomed cylindrical work with the opening hole side down from the lower part to the upper part. SOLUTION: A cooling jacket 30 is arranged below an induction heating coil 20 for heating the inner peripheral surface of the bottomed cylindrical work 10. A flow- passage change-over means 60 is arranged inside the cooling jacket 30. The flow- passage change-over means 60 feeds hardening liquid 50 supplied into the inner part of the cooling jacket 30 to a downward nozzle 31 until the induction heating coil 20 reaches near the topmost part of the bottomed cylindrical work 10 and feeds the hardening liquid 50 supplied into the inner part of the cooling jacket 30 to an upward nozzle 32 after the induction heating coil 20 reaches near the topmost part of the bottomed cylindrical work 10. The hardening liquid 50 is supplied to the last heating part of the inner peripheral surface of the bottomed cylindrical work 10.</p> |
