PISTON SKIRT WITH FRICTION REDUCING OIL RECESS AND OIL RESERVOIR

摘要

A piston (20) includes a piston skirt (30) extending along a longitudinal axis (L) and having a pair of convex outer surfaces (42) facing opposite one another. Each of the outer surfaces (42) include an oil reservoir (44) above the pin bore axis (P) and an oil recess (46) below the pin bore axis (P) and spaced from the oil reservoir (44) by an intervening oil spreading area (48). The oil reservoir (44) and oil recess (46) each include a bottom (50) extending over an area of the outer surface (42) and surrounded by ramped side walls (52). The oil recess (46) and oil reservoir (44) include radiused corners (54) at a transition between the outer surface (42) and at the bottoms (50), so that the oil reservoir (44), oil recess (46), and outer surface (42) are free of sharp edges.