HIGH-PRESSURE COPING ROCKING PISTON

摘要

PROBLEM TO BE SOLVED: To provide a rocking piston which can cope with even high pressure by improving a lip ring.SOLUTION: A rocking piston 4 comprises: a disc-shaped piston body 8 which is integrally arranged at the tip of a connecting rod 6 and slides while rocking in a cylinder 1; a ring presser 20 arranged at the upper part of the piston body 8; and a non-metal lip ring 14 which is arranged between the piston body 8 and the ring presser 20 and seals a gap between the internal face of the cylinder 1 and itself. The lower face 30 of a base 25 of the lip ring 14 face-contacts with the upper face of the piston body 18 toward the side of a cylinder 2 from a region 29 vertically crossing at least the inside end 28a of a curved face of an inside corner 28 at which the base 25 and a lip 15 contact with each other at both inside faces.