Piston pins and piston pin circlips

Abstract

The piston pin is the link between the piston and the connecting rod. Owing to the oscillating motion of the piston and the overlay of gas and inertial forces, it is subjected to high loads in alternating directions. Figure 2.1 shows the piston pin load for a gasoline engine at rated power. The rotational motion of the connecting rod relative to the piston must be compensated for at the bearing locations of the piston pin, in the piston pin boss, and the small end bore. Because of the small relative motions, the lubrication conditions here are poor.