PURPOSE: To prevent the bending caused by welding of a shaft member by inserting a mandrel into a hollow part of the shaft member to weld a cam and a journal part, and tempering them to draw the mandrel out of the hollow part.
CONSTITUTION: After a mandrel 5 is inserted into a hollow part 3a of a shaft member 3 to prevent the bending of the shaft member 3, a cam member 1, a journal member 2 and the shaft member 3 are severally welded over their whole circumference by irradiating a high energy beam 6 to obtain a cam shaft material 7, and then the cam shaft material 7 having been welded is tempered with the mandrel inserted in it, and the mandrel 5 is drawed out of the hollow part 3a of the shaft member 3. In the case where the mandrel 5 is drawed out after the tempering of the cam shaft material 7 in this way, since stress caused by welding in the welded part of the shaft member 9 has been relieved by tempering, the shaft member 3 does not bend even when the mandrel 5 is drawed out of the hollow part 3 of the shaft member 3.
MIWA YOSHIHISA
MAEKAWA TOKIO
HANAKAWA KATSUNORI
