| 摘要 |
<p>A hydraulic system (1) according to the first invention, wherein intermediate pressures between pressures at the inlets and the outlets of first and second pressure compensated valves (4), (4') are caused to act on pressure-receiving surfaces (4b), (4b') on the flowrate decreasing side through first and second intermediate pressure supplying means (13), (13'), so that errors in operation and malfunctions of the pressure compensated valves (4), (4') can be controlled. A hydraulic system (20) according to the second invention, wherein control valves (3), (3') are in neutral positions, holding pressures of hydraulic actuators (5), (5') are caused to act on pressure-receiving surfaces (4b), (4b') on the flowrate decreasing side of the compensated valves (4), (4') so as to hold a spool in a position of compensation, so that responsiveness of the hydraulic actuators (5), (5') to the lever operations can be improved. A hydraulic system (30) according to the third invention, wherein at least one of the areas of the pressure-receiving surfaces (4a), (4a') on the flowrate increasing side of the pressure compensated valves (4), (4') is set larger than the area of the pressure-receiving surfaces (4b), (4b') on the flowrate decreasing side so as to decrease the accuracy of the pressure compensation, so that the maximal operation speeds of the hydraulic actuators (5), (5') can be prevented from being lowered.</p> |
