HEATING COIL FOR INDUCTION-HARDENING CYLINDRICAL BODY HAVING OPENING PART ON OUTER PERIPHERAL SURFACE AND HARDENING COOLING METHOD

摘要

PROBLEM TO BE SOLVED: To provide a heating coil for induction-hardening, by which the inner or the outer peripheral surfaces of a cylindrical body having a plurality of opening parts along the outer peripheral surface and the peripheral surfaces of the opening parts are efficiently hardened. SOLUTION: This heating coil is composed of one pair of main conductors 11, 12 disposed at the inside or the outside of the cylindrical body and formed along grooves of the opening parts, one pair of annular sub-conductors 13, 14 and one pair of current supplying conductors 15, 16. The one end part of one side of the main conductor 11 is fixed to the one side of the sub-conductor 13 and the one end of the other side of the main conductor 12 is fixed to the other side of the sub-conductor 14, and the other end of one side of the main conductor 11 is fixed to the position apart at 180 deg. to the fixed position of the one end of the other side of the main conductor 12 in the other side of the sub-conductor 14. Then, a coil circuit is formed by connecting the respective current supplying conductors 15, 16 at the position apart at 180 deg. to the fixed position of the one end of one side of the main conductor 11 in the one side of the sub-conductor 13 and at the other end of the main conductor 12 to supply the high frequency induction power in the coil circuit through the current supplying conductors 15, 16.