| 摘要 |
PURPOSE:To secure intake air-fuel mixture quantity as well as enhance rigidity on a skirt portion by providing the piston skirt portion with air-fuel mixture intake holes, and forming a circumferential rib at the substantially central position between the air-fuel mixture intake holes along the inner circumferential wall of the skirt. CONSTITUTION:Air-fuel mixture intake holes 16a, 16b are provided on a piston skirt portion 5a, and a rib 18 is formed in the circumferential direction along the inner circumferential wall of the skirt corresponding to about vertically central position between the air-fuel mixture intake holes 16. Therefore, it is possible to enhance rigidity on the skirt portion while securing sufficient intake air-fuel mixture quantity, so as to reduce piston stroke noise. |
