Patent ID: 6325385
Filing Date: 2001-12-04
Classification: F16J,Y10S

Abstract:
A piston ring having a diamond-like carbon film on a sliding surface of said piston ring, wherein an under film is formed beneath said diamond-like carbon film, and consists of one or more elements selected from the group consisting of silicon, titanium, tungsten, chromium, molybdenum, niobium and vanadium in an atomic content of 70 percent or more and below 100 percent, and the remaining content consisting of carbon; or one or more elements selected from the group consisting of silicon, titanium, tungsten, chromium, molybdenum, niobium and vanadium in an atomic content of 100 percent, and the thickness of said under film is within a range of 1 to 35 percent of the sum of said diamond-like carbon film thickness and said under film thickness, and said diamond-like carbon film is worn and said under film is exposed during use of said piston ring.