Cooling jacket for internal hardening of cylindrical workpieces

摘要

PROBLEM TO BE SOLVED: To provide a cooling jacket suitable to a sub-jacket in the case of shiftingly hardening both wall surfaces of groove parts arranged at plural positions in the peripheral direction on the inner surface of a cylindrical work. SOLUTION: This cooling jacket is constituted of a laminated body 40 constituted by laminating plural plate materials 41, 42, 43. A first flowing passage is formed between the plate materials 41, 42 by the radiating groove parts 41b arranged on the upper surface of the plate material 41. A second flowing passage is formed between the plate materials 42, 43 by the radiating groove parts 42b arranged on the upper surface of the plate material 42. The laminated body 40 is connected with the front in the shifting direction of a heating coil for heating both wall surfaces of the groove parts arranged at plural positions in the peripheral direction in the inner surface of the cylindrical work, and the cooling liquid is injected onto the bottom surface of the groove part. At the same time of completing the heating of both wall surfaces, the cooling liquid is supplied into the second flowing passage at the upper stage and injected onto both wall surfaces of the groove part to rapidly cool and harden the last heating part on both wall surfaces. Since the thickness of the laminated body 40 is thin, both wall surfaces are heated and hardened to the edge parts.