| 摘要 |
PURPOSE:To obtain high precision piston with low cost by providing a surface layer of plastic on a core material of high rigidity and high strength. CONSTITUTION:The piston A consists of a core 2 and a plastic surface layer 1. The core 2 is made of material of high rigidity and high strength; metal, ceramic, etc.; and the plastic surface layer 1 is manufactured by press forming, transfer forming, or injection molding. As a result, due to excellent surface smoothness and dimensional accuracy of the metal die used for forming of the plastic surface layer 1. A piston having smooth surface, accurate circularity and diameter can be obtained. |
