| 摘要 |
<p>This hydraulic drive unit (1) drives actuators (7, 9, 10) by supplying said actuators (7, 9, 10) with a hydraulic oil discharged from a hydraulic pump (11). The hydraulic drive device (1) is provided with operation valves (13, 14), a flow rate control mechanism (12), an electromagnetic proportional control valve (27), a failsafe mechanism (25), and a bleed-off valve (15). If the pressure difference between an output pressure (Prcv) and a control pressure (Psol) is within a configured control range (52) set in advance, the failsafe mechanism (25) outputs the control pressure (Psol) as a pilot pressure (Ppil), and, if said pressure difference is not within the configured control range (52), outputs the output pressure (Prcv) as the pilot pressure. The bleed-off valve (15) adjusts the opening area depending on the pilot pressure (Ppil), and discharges the hydraulic oil from the hydraulic pump (11) into a tank at a flow rate depending on the opening area.</p> |
