摘要 |
A piston (1) has a combustion chamber (5) formed in the piston top surface and also has an oil gallery (6) formed so as to surround the combustion chamber. The wall thickness of the piston, which is measured from the slide side surface of the piston to the oil gallery thereof, is set such that the piston skirt side (B) has a greater thickness than the piston top surface side (A). |