| 摘要 |
A cylinder has at least one valve seating surface-forming portion which has an outer surface formed therein with at least one recess, the bottom surface of which serves as a valve seating surface. A discharge valve is arranged on the outer surface of the valve seating surface-forming portion to close or open outlet holes formed in respective ones of the valve seating surface at locations where the wall thickness of the cylinder is the minimum. The discharge valve has at least one elastic valve body having an arcuate cross section and disposed in tight contact with a corresponding one of the valve seating surface. The valve seating surface is arcuately concavely curved with almost the same radius of curvature as that of the valve body of the discharge valve. |
