Abstract: An internal retaining ring for placement in a bore of an outer component of a rotating assembly comprises a semi-annular body having an outer circumferential surface with a curvature defined about a first center of curvature and radially outward protruding anti-rotation tabs operable for engagement with a corresponding anti-rotation feature of the outer component. An inner circumferential surface of the semi-annular body has radially inward protruding tabs circumferentially spaced apart around the inner circumferential surface. The radially inward protruding tabs have radially inner surfaces concentric with the outer circumferential surface, and recessed portions between the radially inward protruding tabs and having curvatures defined about a second center of curvature, the second center of curvature different from the first center of curvature.

Abstract: Improved liquid lubricated piston ring gas seals with reduced friction and wear compared to prior art rings are disclosed for use in internal combustion engines, gas pumps, and gas compressors. These improved rings allow independent adjustment of the parameters controlling friction and wear, and eliminate the tradeoff between friction and wear typical of prior art rings.