| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a piston ring in which wear resistance, gas sealing and oil scraping properties can be satisfied at the same time, and hard film itself formed on its sliding surface is never peeled off. <P>SOLUTION: In a piston ring comprising a base material having a concave portion formed in an outer peripheral surface and a hard film provided in the concave portion, in a cross-section perpendicular to a radial direction of the piston ring, the concave portion is configured to include a first surface extending parallel to the outer peripheral surface of the piston ring from either one of the top and bottom surfaces of the base material toward the other, and a second surface extending toward the outer peripheral surface of the piston ring from one end of the first surface. By providing hard film to the concave portion, the outer peripheral surface of the piston ring is configured such that a portion where the hard film is formed and a portion where the base material is exposed are made present, and the second surface where the concave portion is formed and the outer peripheral surface of the piston ring is made contact with each other with an angle of 10 to 30 degrees. <P>COPYRIGHT: (C)2013,JPO&INPIT |
