| 摘要 |
PURPOSE:To prevent the peeling of plating when a fitted surface part is cut, by arranging a nonplated region at a specific part which is continuous to the fitted surface part onto which a cylinder head is fitted among the inside diameter part of a sleeve into which a piston is accommodated. CONSTITUTION:A sleeve fitted into the cylinder block of an engine 10 is equipped with an inside diameter part 16 into which a piston is accommodated and a fitted surface part 14A on which a cylinder head is fitted. The sleeve is formed from a basic member made of Al alloy, and the inside diameter part 16 is applied with a plating part 17. In this case, the part which is continuous to the fitted surface part 14A of the inside diameter part 16 and onto which a piston ring does not slidingly contact is formed into a large opening diameter, and a non-plated region 24 is arranged at this part. Also, in the case where a cutting tool for shaping the fitted surface part 14A reaches the edge part of the fitted surface part 14A, exfoliation of plating on the inside diameter part 16 which is continuous to the edge part is eliminated. |
