| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a combined oil control ring in which a function for preventing independent rotation of a side rail is imparted thereto, the function is maintained over the long term, and further, the independent rotation of the side rail can be prevented even in a low-tension combined oil control ring. <P>SOLUTION: A combined oil control ring comprises upper and lower two side rails and a space expander which is interposed between the side rails and includes, in its inner peripheral part, a flange part pressing inner peripheral surfaces of the side rails. A side rail pressing surface of the flange part has irregularities extending in a substantially axial direction, and cross sections of the irregularities are substantially formed in trapezoidal waveform shapes. <P>COPYRIGHT: (C)2013,JPO&INPIT |
