Manufacturing methods and hollow cam shaft of hollow cam shaft

摘要

PROBLEM TO BE SOLVED: To provide a manufacturing method for hollow cam shaft capable of reducing its weight and having excellent productivity and the hollow cam shaft being manufactured by this method and having excellent strength and durability. ;SOLUTION: This cam shaft is constituted in such a way that a raw material steel pipe having an outside diameter which is intermediate dimension between a diameter (Rb+h2) of an outer face of a cam lobe part 13 of a cam shaft rough material 10 and an outside diameter (2Rj) of a journal part 12 is used to shrink a diameter of a journal equivalent section of the raw material steel pipe and machine it in advance by plastic machining using a mold and then a wear-resistant material is built up by laser metal filling on a cam slide face of the cam shaft material 10 obtained by bulging and molding the cam lobe part 13. Consequently, it is possible to obtain a hollow cam shaft 1 in which, for example, an outside diameter (2Rs) of a cam shaft part 4 cylinders is larger than an outside diameter (2Rjf) of a journal part 2 positioned between cam lobe parts 3 and 3.;COPYRIGHT: (C)2000,JPO