Oil seal construction for rotary internal combustion engine

Claim 1

A rotary mechanism comprising: an outer body having spaced side walls and a peripheral wall interconnecting said side walls for defining inbetween a cavity having an axis along which said side walls are spaced from each other; an inner body received within said outer body cavity and supported by said outer body for eccentric rotation relative to the axis of said outer body cavity, said inner body having side surfaces adjacent to said outer body side walls and a peripheral surface cooperating with said outer body peripheral wall for forming inbetween a plurality of working chambers in the course of the relative rotation of said inner body, and an oil seal construction including, a generally annular groove formed in each of said inner body side surfaces and having a generally rectangular cross section, an oil seal ring relatively tightly received within said annular groove with a limited clearance inbetween for sealing engagement with the inner surface of each of said outer body side walls, and biasing means mounted between said annular groove and said oil seal ring for urging said oil seal ring toward said each of the outer body side walls to effect the sealing engagement of said oil seal ring, the improvement comprising said oil seal ring having at least the side surface thereof adjacent to the bottom of said annular groove locally reduced for effecting smoothly sliding engagement with the associated inner side surfaces of said annular groove responsive to any axial rocking motions of said inner body along the axis of said outer body cavity to insure effective sealing engagement of said oil seal ring with said outer body side walls.