To provide a method for producing a cam shaft by which low-speed a cam and a high-speed cam , which are different in base organization can be molded by a single mold, and also a gap between the llow-speed cam and the high-speed cam can be formed by a casting stage, and to provide a structure of a mold for castsing the cam shaft.
A chill block 27 molding the nose part of a low-speed cam is arranged at the inside of a mold 20, and a heat shield plate 28 molding an annular side edge face 28d orthogonal to the axis of both the cam cavities is arranged, thus the base material of the nose part in the low-speed cam can be chilled in a clearance groove between the low speed cam cavity 25 and the high-speed cam cavity 23, and the chilling of the nose part in the high-speed cam can be prevented. After a casting stage by the single mold 20, the mold 20 is shaken out, the chill block 27 is removed from the cam shaft, the cam shaft is subjected to glass shot blast treatment, and the heat shield plate 28 is destroyed and removed from the gap groove of the cam shaft, thus the moldability of the gap groove can be increased.
ASAKURA YOJI
TONE HIDEO
MIYOSHI TATSUYA
