| 摘要 |
PURPOSE:To improve the operative characteristic of an actuator for a scavenging control control valve, by providing two oil hydraulic pumps to be switchably driven while an oil discharging valve parallelly to said pumps in a supply path of pressure oil to the oil hydraulically driven scavenging control valve. CONSTITUTION:A driving gear, providing a scavenging control valve 3 in a scavenging hole 36 provided in the side part of a cylinder 1, closes the valve 3 when pressure oil is fed to a bottom side chamber 39 of a piston 40 in an actuator 7. In the initial time of closing the valve 3, the driving gear, supplying pressure oil from the second oil hydraulic pump 47 to the chamber 39 through a valve 41 and pipes 45, 44 by a signal of the second driving circuit 26, starts to close the valve 3. At this time, air in a chamber 38a is gradually compressed. Next the driving gear, switching a valve 29 and supplying pressure oil from the first large output oil hydraulic pump 31 to the chamber 39, closes the valve 3. In this way, when the valve 3 is opened, the pressure oil in the chamber 39, being pressed by high pressure air because pressure of the air in the chamber 38a increases to a high pressure, can be rapidly discharged if a delivery valve 42 is opened by switching a valve 43.
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