| 摘要 |
PURPOSE:To insure excellent sealing ability by forming lips on both ends of a resin ring pressed into contact with the outer circumference of a piston, and expanding either of lips even at applying pressure from either of both sides of the piston. CONSTITUTION:A resin ring 3 is pressed into contact with the outer circumference of a piston 1 inserted in a cylinder 2. The ring 3 is provided with recessed grooves 5 fitted with a plurality of projections 4 provided on the piston 1, and liquidtightly fitted. Lips 6, 7 expanding outward in the radial direction are provided on both ends of the ring 3. Inside the lips 6, 7, O-rings 8, 9 pressing the lips 6, 7 to expand in the radial direction are mounted in grooves 10, 11. Consequently, when pressure is received from a chamber S, the expanding force is applied on the lip 6 to raise the seal face pressure, and when pressure is received from a chamber S, the expanding force is applied on the lip 7 to raise the seal face pressure. |
