PISTONS

摘要

A piston generates reduced noise in operation by the provision on its lateral bearing surfaces of two or more depressions in which oil is stored to provide a cushion against lateral movement of the piston at points of a reciprocation of the cycle where noise is generated. The depressions have a maximum depth of only 125 microns below the surrounding bearing surfaces formed on the piston. The depressions have circumferentially extending edges which are formed with steps connecting the depressions to the surrounding bearing surface.