| 摘要 |
<p>PURPOSE:To improve operability by changing relief pressure of a hydraulic driving circuit according to the magnitude of operation force applied to an operation lever to highten an operator's sense of operation of a hydraulic actuator. CONSTITUTION:A directional switch valve 11 and a relief valve 23 are disposed in an oil pressure apply/discharge pipeline connected to a hydraulic cylinder 9. On the other hand, pilot valves operated by an operation laver 13 are disposed in pilot pressure pipelines Pa, Pb, respectively. A distorsion gauge 22 is provided on the operation lever 13, and its detected position is input to a pressure control circuit 24. The pressure control circuit is adapted to change relief pressure of the relief valve 23 according to the magnitude of operation force applied to the operation lever, so that an operator's sense of operation is matched with the human natural operation sense.</p> |
