| 摘要 |
PURPOSE:To improve the reliability and the durability of a captioned device by providing V-shaped notch faces on the backside face of a plurality of laminated piston rings and a back-up ring on the backside of a seal ring of an almost semi-circular section in contact with these notch faces. CONSTITUTION:On the backside part of piston rings 16 and 17 fitted in a piston ring groove 5 of a piston 1, chamfering slant faces 16B and 17B are provided in the whole circumference to make a V-shaped groove between them. Meanwhile, a seal ring 19 is shaped into an almost semi-circular section with a circular face 19A faced outward to be in touch with the V-shaped groove. A back-up ring 18 wavy on a plane is fitted between the seal ring 19 and a ring groove bottom 5A. An inward-convexed part of the back-up ring 18 is elastically in touch with the ring groove bottom 5A, and an outward-convexed part is elastically in touch with the inner circumferential face 19B of the seal ring. This construction permits to obtain a sufficient sealing capacity in piston rings 16 and 17. |
