| 摘要 |
A fluid-pressure drive device (1) drives actuators (7, 9, 10) by supplying a hydraulic fluid discharged from a fluid-pressure pump (11) to the actuators (7, 9, 10). The fluid-pressure drive device (1) has operating valves (13, 14), a flow-control mechanism (12), a back-pressure output mechanism (25), and a bleed-off valve (15). The operating valves (13, 14) output an output pressure according to the angle of tilt of operating levers (13a, 14a). The flow-control mechanism (12) adjusts aperture according to the output pressure of the operating valves (13, 14), and supplies the hydraulic fluid to the actuators (7, 9, 10) at the flow corresponding to the aperture. The back-pressure output mechanism (25) outputs back pressure (pa) according to the state of operation. The bleed-off valve (15) is positioned in parallel to the flow-control mechanism (12), and discharges, to a tank, pressurized fluid at a flow corresponding to the pressure difference (&Dgr;p) between the bleed-off pilot pressure (pb) and the back pressure (pa) of the back-pressure output mechanism. |
