| 摘要 |
PURPOSE: To prevent damage due to repulsion from a boss on the side of a piston pin by providing a piston body formed with the boss for surrounding an inner space, and fitting a pair of bushes to pin holes penetrating the boss, each bosh showing a specified angle in its outer peripheral surface on the side of the inner space in respect to an inner peripheral surface of the pin hole. CONSTITUTION: A piston 10 for an internal combustion engine 10 has a piston body 11 made of mother material of aluminum alloy which is integrated with a boss 13 for determining an inner space 12. A pair of pin holes 14 are formed on the boss 13 for penetrating the boss in a diameter direction. A bush 15 is inserted into each pin hole 14. An inner peripheral surface of the pin hole 14 on the side of the inner space 12 is widened and formed so as to show an angleθ(between 3 and 5 degrees) in respect to an outer peripheral surface of a cylindrically formed bush 15. Generation of inner damage due to repulsion from the side of a piston pin 17 whose both ends are fitted to each bush 15 is prevented.
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