Patent ID: 7621244
Filing Date: 2009-11-24
Classification: F01L,Y10T

Abstract:
1. A tappet for use with a valve system of an engine, the tappet comprising: a bottom portion and a cylindrical tubular portion extending from the bottom portion, wherein an outer wall surface of the cylindrical tubular portion is configured to contact an inner peripheral surface of a tappet hole of the valve system of the engine and to be slidably supported in the tappet hole, and wherein an outer surface of the bottom portion is configured to slidably contact an outer peripheral surface of a cam of the engine, and wherein at least the outer wall surface of the cylindrical tubular portion and the outer surface of the bottom portion are subjected to a surface hardening process selected from the group consisting of a carburizing process and a nitriding process; wherein the tappet is made of a titanium alloy; and wherein after removing an oxidization film from the surfaces which have been subjected to the surface hardening process, a diamond like carbon film is formed on the surfaces.