Patent ID: 6834861
Filing Date: 2004-12-28
Classification: C22C,C23C,F16J

Abstract:
A two piece oil control ring comprising a ring body formed into a generally M- or I-shaped section with an annular groove on an inside surface of the ring body; and a coiled expander attached in the annular groove of the ring body for resiliently urging the ring body toward an inner wall of a cylinder,said ring body comprising an upper rail, a lower rail and a web that connects said upper and lower rails, said web being provided with a plurality of openings for allowing lubricating oil to pass therethrough, said ring body being made of stainless steel that contains chromium of 3.0 to 13.0 weight % with the outer and inner circumferential surfaces covered with nitrided layers, and a circular ratio of an outer surface length to an inner surface length in the cross section of the ring body being in a range between 1.08 and 1.32.