Articulated piston having a profiled skirt

摘要

An articulated piston includes a crown and a separate skirt joined in articulated manner to the pin bosses of the crown by a wrist pin. The skirt has opposing thrust surfaces which contact the wall of a cylinder bore of an engine when the piston experiences side loading during operation. The thrust surfaces have a vertical profile which is generally symmetrical about a center plane containing the axis of a pin bore of the skirt. The profile includes tapered end sections and a wide, shallow central depressed region. Under normal operation, the depressed region channels lubricant to the pin bores. The twin peaked profile distributes side loads and stress above and below the pin bore plane and under heavy load, the depressed region bows outwardly presenting a flat, full contact surface between the peaked regions for decreasing the wear load on the thrust surfaces.