| 摘要 |
PROBLEM TO BE SOLVED: To provide a cold forming method of a tapered piston pin with a central partition or without the partition by a single forming process. SOLUTION: The method can eliminate secondary processes such as a machining process, an annealing process, a coating process, a secondary forming process and others not limited by these examples. The method includes steps of: cutting a metal bar into small columnar pieces; forming a first cavity in the small piece by extruding the small piece using a metal die; forming a second cavity in the small piece by extruding the small piece using an arbitrary metal die; forming the small piece into a hollow cylindrical piece by piercing the small piece; and forming the hollow cylindrical piece having a taper on the inner surface of each end of the hollow cylindrical piece by extruding each end of the hollow cylindrical piece using a metal die. COPYRIGHT: (C)2008,JPO&INPIT |
