| 摘要 |
<P>PROBLEM TO BE SOLVED: To eliminate response delay as a switching valve is opened to start a machine while relaxing a shock at the stop of the machine as a J/S (hydraulic joystick valve) is returned to the neutral. <P>SOLUTION: In a hydraulic circuit having a pilot operated switching valve for switching the direction of pressure oil supplied to an actuator by pilot pressure from the J/S, in an oil path from a hydraulic pump to the actuator, pilot valves each having a spring in parallel with an orifice are provided, on pilot lines on both sides of the pilot operate switching valve. When the pilot pressure is increased, pilot pressure acting on the one pilot valve becomes higher than pressure set by the spring of the one pilot valve, thus opening the one pilot valve, and simultaneously acting in a direction to open the pilot vale, the other pilot valve is brought into a valve-opened state, and meanwhile, when the pilot pressure is decreased, return oil of the pilot operated switching valve is passed through the one orifice while the one pilot valve is brought into a valve-closed state by the spring. <P>COPYRIGHT: (C)2012,JPO&INPIT |
