| 摘要 |
PROBLEM TO BE SOLVED: To provide a manufacturing method of a valve shaft by which the valve shaft can be manufactured at low cost, and prevented from being damaged and so on as much as possible. SOLUTION: The manufacturing method of the valve shaft comprises: a shaft material cutting process of forming a shaft body 2 composed of a tip A, a center B, and a rear portion C which are different in diameter by cutting a cylindrical shaft material 1; a shaft body forging process of forming a shaft body 3 with a brim having a D-cutting portion 13 and the brim 11 by applying cold forging to the shaft body 2 obtained by the shaft body cutting process; and a flanged shaft body forging process of forming a screw a at the tip A by applying rolling processing to the flanged shaft body 3 obtained by the flanged shaft forging process. COPYRIGHT: (C)2008,JPO&INPIT
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