| 摘要 |
PURPOSE:To eliminate the undesirable influence due to dirty oil by varying and setting the pulse width under a constant frequency and controlling the flow rate in the balanced state between a spring and the electromagnetic force. CONSTITUTION:An ON/OFF switch 4 is installed, thereby the switch can selectively conduction-operate the extension side electromagnetic part 8a and the contraction side electromagnetic part 3b of a selector valve V, and a pulse signal generating circuit 5 for opening said valve is connected in series to the selector switch 4. An operating mechanism 6 for controlling the opening degree of the valve is installed, while said valve varies and sets the pulse width in the constant frequency state, and then a hydraulic cylinder 1 is extended and contracted, while controlling the flow rate. Thus, the undesirable influence due to dirty oil can be avoided. |
