| 摘要 |
<p>A steel piston ring (1), wherein grooves (5, 6) of generally square shape in cross section of 0.05 to 0.4 mm in the length of one side or generally quarterly circular shape in cross section of 0.05 to 0.4 mm in radius are formed at a corner part (2) formed of an outer peripheral surface (4) and a lower surface (3), a sharp edge (9) formed of the grooves (5, 6) performs an oil scraping action, and the grooves (5, 6) act to lower oil pressures on a second land and a third land.</p> |
