| 摘要 |
PURPOSE:To reinforce an opening edge part so as to improve its quality against a thermal crack, by compounding an inorganic fiber aggregate with the opening edge part of a combustion chamber comprising a cavity part on the top face of a piston. CONSTITUTION:In the case of a piston 11 cast from the metal such as an aluminum alloy and provided with a cavity part forming a combustion chamber 12 on the top face, an inorganic fiber aggregate 10 of ring shape is compounded in an opening edge part of the combustion chamber 12. The aggregate 10 uses a material, for instance, mixing 95% aluminum oxide with 5% silicon dioxide and having a 3mu average diameter and the aspect ratio of fiber not more than 200. When the piston 11 is manufactured, the ring shaped aggregate 10 is pressurized after injecting the aluminum alloy molten in a mold under the condition such that the aggregate is arranged in a position, corresponding to the opening edge part of the combustion chamber, of the piston casting mold. The molten metal in this way is intruded into a void between the fibers of the aggregate, thus reinforcing combination between the both aggregate 10 and the piston 11. |
