Patent ID: 7354045
Filing Date: 2008-04-08
Classification: F16J

Abstract:
1. An oil ring formed into cross-section substantially of an I-shape that two rails are connected at a columnar portion thereof, wherein a sliding projection formed in each of the two rails comprises an outer side surface of sliding projection which forms an outer portion of the sliding projection, a inner side surface of sliding projection which forms an inner portion of the sliding projection, and a sliding surface which slides on a cylinder inner wall and forms a tip end of the sliding projection; wherein a taper angle of the outer side surface of sliding projection is in a range of 10° to 60°; said sliding surface is not in symmetry about the center line; an outer edge portion, where the outer side surface of sliding projection and the sliding surface are joined to each other, is formed into a curved surface, and the sliding surface has a curved surface sliding portion which is joined to the outer side surface of sliding projection and formed into a gently curved surface; and a radial width of the oil ring, which is from the portion where the curved surface sliding portion and the outer side surface of sliding projection are joined to each other to the portion where the sliding surface and the inner side surface of sliding projection are joined to each other, is from 3 μm to 100 μm.