| 摘要 |
PURPOSE:To reduce the number of manufacturing processes by cutting an extrusion-molded round pipe, provided with fins extended in the axial direction, to the desired length to obtain a short pipe, cutting also the fins in the vicinity of both ends of the short pipe, and after applying quenching, forming a fiber reinforced plastic layer along the cylinder surface provided with the fins. CONSTITUTION:Steel as raw material is extrusion-molded to manufacture a long-sized round pipe. In this case, plural fins 1a extended in the axial direction are simultaneously formed at the inner surface of the round pipe 1. This round pipe 1 is cut to the length of a piston pin to manufacture a short pipe 1, as well as the fins 1a in the vicinity of both ends of the short pipe 1 are cut. After the process of quenching, a fiber reinforced plastic layer 2 is formed along the inner surface of the short pipe 1 by injection molding and reinforced, and then its outer diameter is ground to the desired measure. A composite piston pin light in weight while maintaining strength and rigidity as a pin as well as with high material yield can be thus manufactured in the small number of processes. |
