| 摘要 |
PURPOSE:To reduce back pressure in the uppermost stage ring groove, by forming gas passages each extending from the lower ring grand of each ring groove excepting the lowermost stage ring groove with a gas tight ring being inserted in each groove, for communicating spaces in the ring grooves. CONSTITUTION:Gas tight ring 11 each having upper and lower mating faces in its joint part which are made in close contact together for preventing gas leakage therethrough, are inserted in ring grooves 31 through 34 formed in a piston 1. Gas passages 5 each are formed in the lower grand 41 through 43 of each of the ring grooves 31 through 33 excepting the ring grand 44 of the lowermost stage ring groove 34, for communicating between rear spaces in the upper stage ring groove and upper spaces in the lower stage ring grooves. Accordingly, the pressure of combustion gas is uniformly distributed to all piston rings, and therefore, the back pressure applied to the uppermost piston ring is reduced, thereby deterioration in slidability, abrasion in the slide surfaces, etc. are may be prevented. |
