Patent ID: 7510196

Claim:
An oil ring for an internal combustion engine comprising upper and lower rails for scraping oil, and a web connecting the upper and lower rails to each other, wherein the web is provided with an oil-passing hole which is formed long in a circumferential direction of the oil ring, the oil-passing hole includes: two arc portions disposed at both ends, so as to be opposed to each other; two parallel straight portions disposed so that a widthwise direction distance therebetween is longer than a width of the arc portion; and inclined portions for connecting the arc portions and the parallel straight portions to each other, and wherein a height of a main body of the oil ring for the internal combustion engine is defined as h 1 , a distance between the two parallel straight portions of the oil-passing hole is defined as h 2 , a radius of curvature of the arc portion is defined as R and a central angle of the arc portion is defined as 0, and R/h 1 =0.05 to 0.20, 0=90 to 160Â°, 2R<h 2 , and h 2 /h 1 =0.15 to 0.6.