| 摘要 |
PURPOSE:To prevent leak of a working gas at a piston and its neighborhood by furnishing two or more slits at the outside surface of a displacement piston, which are to put the expansion chamber in communication with a ring groove formed in the piston ring. CONSTITUTION:Slits 16 are formed at the outside surface of a displacement piston 13 from the top surface 14 of piston 13 till a piston ring groove 15. High pressure gas P in an expansion chamber situated in the upper part of the piston 13 is sent through a piston clearance 19, which is formed by the outside surface of a cylinder 17 and the piston periphery 18, and reaches the piston ring 20 fitted in the above-mentioned piston ring groove 15, so as to put the piston ring 20 in contact with the lower side face 15 of the ring groove 15. Thus the gas is sealed. |
