| 摘要 |
PURPOSE:To secure a flow of hot water so as to prevent generation of casting failure when casting a piston to be connected to a connecting rod the small end of which is axially attached to a piston pin inserted into the pin hole of a pin boss, by chambering the opposite inner ends of the pin boss. CONSTITUTION:A piston 1 is casted using a light alloy, and a pin boss 2 is formed to protrude integrally from the opposite ends of the cup-shaped inner side of the piston. The pin boss 2 has a lower hole 3 provided at one portion and also a chamfering 4 provided integrally at its inner edge during casting. The chamfering 4 is gouged out largely in the same direction as the vertical axis of the piston and a little in its horizontal direction. Besides, the lower hole 3 portion is formed as a precise pin hole 5 via a cutting process using a drill, and a piston pin to which the small end of a connecting rod is axially attached is inserted into the hole to connect the piston 1 and the connecting rod together. |
