| 摘要 |
<p>PURPOSE:To quicken responsiveness at a low cost by controlling a pair of solenoid proportional pressure controlling valves which are inserted in a vent circuit of a relief valve for controlling pressure of hydraulic circuit through a switching solenoid directional changeover valve so that one of them is operated under a next preset pressure when the other is operated. CONSTITUTION:A solenoid directional changeover valve 5 for selecting either one of a pair of solenoid proportional pressure controlling valves 6, 7 is inserted in a vent circuit 4A of a relief valve 4 which controls hydraulic pressure to an actuator 3. The controlling valves 6, 7 are controlled by signal switchers C12, C13 for selecting respective one of signals form program controlling pressure setters 14, 15, while the signals are switched alternately by a signal switcher B11. The solenoid directional changeover valve 5 is controlled by a pressure controlling device including a signal switch A8. One of the solenoid pressure controlling valves 6, 7 is operated, and the other is operated under a next preset pressure before switching according to the program. Controlling is preformed with quick responsiveness at a low cost.</p> |
