| 摘要 |
PURPOSE:To improve resistance to abrasion and lubricating properties between the piston pin and the holes for the piston pin by a method wherein the surfaces of the piston pin holes of the internal-combustion engine are processed by aluminum anodizing, inverse electro-plating of a hard metal such as chrome or the like to form a porous film. CONSTITUTION:The skirt 102 of the piston 10 is provided with the piston pin holes 104 at the intermediate part thereof concentrically so as to be separated into left and right, since a cavity 103 is provided at the inner diametral part of the skirt 102, and both ends 131 of a pin 13 are fitted into the holes 104 for the pin while the intermediate part 132 of the pin 13 is connected with the small end 122 of a connecting rod. Both ends 131 of the pin 13 are fitted pivotally into the holes 104 for the pin and both axial ends 133 of the pin 13 are retained axially by clips 15 being engaged with annular grooves 105. The piston pin 13 is made of nickel chrome molybdenum steel, for example, and the inner peripheral surfaces of the piston pin holes 104 are processed by aluminum anodizing, for example, to form the porous hard film on the inner surfaces of the piston pin holes 104. |
