Stössel in einer Brennkraftmaschine und dessen Herstellungsverfahren

摘要

A tappet (12) in a direct acting type valve operating mechanism of an internal combustion engine comprises a top wall (1) and a cylindrical portion (2). The upper and lower surfaces of the top wall (1) contacts a rotary cam and the end of a stem of an engine valve respectively. A hard metal layer (3,4) is formed at the upper and lower surfaces of the top wall to increase strength thereof, thereby increasing wear resistance and durability of the tappet.