| 摘要 |
PURPOSE:To facilitate holding of an oil film by making a recess formed on at least one of the contact surfaces between a ring-shaped sliding body and a ring- shaped groove to have a surface adjacent to the contact surface being formed to produce an oil film when the sliding body and the groove slide against each other in their relative movements. CONSTITUTION:As a piston ring 6 has its inner peripheral surface formed with a groove 10, its self elastic deformation in a radial direction is easier than a piston ring having the corresponding section made flat. Coupled with the advantage of making its outer peripheral sliding surface 7 circular, the piston ring can constantly retain favorable contact conditions between the sliding surface 7 and the inner surface 8 of a cylinder even when being subjected to irregular load which is caused when a shock absorber is operated. The recess 10 serves as an oil sump, and with its form slightly angled by a degree theta, can easily develop an oil film between the bottom surface of the ring-shaped grokove 5 and the contact surface of the piston ring 6 when piston 3 and piston ring 6 slide against each other in their relative movements and thus prevent any abrasion thereon. |
