| 摘要 |
PURPOSE:To suppress abrasion of the plateau part caused by sliding of a piston ring. CONSTITUTION:A cylinder block 1 made of flake-type black lead cast iron is provided with a cylinder bore 2 in which a piston 3 can make reciprocating motion. A piston ring 4 slides on the inner face of the cylinder bore 2 according to reciprocating motion of the piston 3, and an oil film is formed between the periphery of the piston 3 and the inner face of the cylinder bore 2. Mesh grooves 5 for maintaining the oil film are formed on the inner face of the cylinder bore 2. The grooves 5 are obtained by applying honing process to the hole of the cylinder block 1. The part surrounded by the grooves 5 is the plateau part 7 which receives pressure of the piston ring 4. The plateau part 7 is obtained by applying roll burnish process so as to be plastically deformed, and the surface is smoothly curved, and the surface layer part is harndened. |
