| 摘要 |
PURPOSE:To reduce consumption of lubricating oil, by disposing a check valve permitting lubricating oil to flow only from the lower surface side to the upper surface side of a piston ring at an upper opening of a communicating port formed between the upper surface and the lower surface of the piston ring in the manner of extending through the same. CONSTITUTION:Communicating ports 7, 8 are formed between the upper surface 3b and the lower surface 3a of a piston ring 3, and a check valve 9 in the form of a disk is fitted at the center of the large-diameter communicating port 8 formed in the upper surface 3b of the piston ring 3. In case that the gas pressure in a lower gap 5 becomes higher than that in an upper gap 4 and the piston ring 3 is raised upward by the pressure difference, gas in the lower gap 5 is passed to the upper gap 4 not only through a back clearance 6 but also through the communicating port 7, so that the pressure on the opposite sides of the piston ring 3 are balanced immediately. Thus, since the period when seal is acted between the lower surface of the piston ring 3 and the upper surface of a ring groove formed in a piston 2 is prolonged, it is enabled to prevent rise of lubricating oil. |
