Patent ID: 7494129

Claim:
A one-piece piston ring having a gap, an outer surface, an inner surface, an upper flank, and a lower flank; said piston ring further including a bevel extending between said upper flank and said inner surface, said bevel having an angle measured from a plane perpendicular to said inner and outer surfaces which varies in a circumferential direction of said piston ring such that the angle is smaller in an area adjacent said gap as compared to an area diametrically opposed to said gap; said bevel having a width which also varies in the circumferential direction and which is wider in the area adjacent said gap as compared to the area diametrically opposed to said gap; said lower flank having a radial wall thickness which also varies in the circumferential direction such that said thickness is smaller in the area adjacent said gap as compared to the area diametrically opposed to said gap.