| 摘要 |
PURPOSE:To simplify the constitution and reduce the cost of a control unit including a proportional reducing valve by controlling one direction changing valve with only one proportional control valve. CONSTITUTION:An apparatus for controlling a cylinder 10 by a direction changing valve 11 includes a two-position solenoid valve 14 for selecting pilot paths 12, 13 to the direction changing valve 11 and a proportional reducing valve 15 disposed upstream from the valve 14. The proportional reducing valve 15 is operated in proportional to an input signal, so that in the illustrated condition, a connecting path 19 is connected to a tank 21, and at the time of switching opeation, an auxiliary pump 22 and a connecting path 19 are connected with each other. The solenoid valve 14 and the proportional reducing valve 15 are respectively connected to a direction discrimination circuit 23 and a proportional control circuit 24 and the respective circuits 23, 24 are controlled to operate according to an input signal of an input portion 25. |
