| 摘要 |
<p>PROBLEM TO BE SOLVED: To form a hardened layer along the shape of a cam part requiring the hardened layer of a cam shaft. SOLUTION: In an induction hardening method, a plurality of cam parts are provided on one cam block, and annular heating coils 21a, 21b and 21c of the same winding number and of the same number as that of the cam parts for each cam block are arranged for the cam shaft 1 comprising the plurality of cam blocks via a journal part. The heating coils are followed by a following mechanism 33 while the clearances TG and BG between each of a cam top part 11d and a cam base part 11e of the cam part and an inner circumferential surface of the heating coils are kept constant in a synchronous manner with the rotation around the axis of the cam shaft 1. High frequency current is supplied to the heating coils, the cam part is induction heated, and naturally cooled after the heating. The cam part is cooled by a cooling device 34 to form a hardened layer on the cam part.</p> |
