| 摘要 |
PURPOSE:To secure such a piston as being lightweight and inexpensive as well as excellent in durability, by installing a cylindrical intermediate layer, composed of a metal, around a core part comprising light metals being compositely reinforced by a reinforced fiber as well as installing a hard metallic outer layer around the core part in addition. CONSTITUTION:A fiber molding body composed of a reinforced fiber 3 being made up into spiral form at a pitch angle theta+ or -65-+ or -70 deg. around an axis is formed, while this molding body is set up inside a cylindrical metallic intermediate layer 6 and, after being preheated and put in a mold, molten light metal is temmed in this mold. Then, a part composed substantially of light metals alone is removed from a solidified body obtained by solidifying the molten metal upon pressurization and then the circumference of the intermediate layer 6 is covered with a hard metal, thus an outer layer 7 is formed. Since rigidity and the rate of expansion are accorded with each other with a core part 1 and the intermediate layer 6, no peeling between them happens and, what is more, it comes to being so strong against the stress. Moreover, also in its manufacturing method, it is inexpensive and excellent in efficiency as well as in cohesion between the light metal, the reinforced fiber 3 and the intermediate layer 6. |
