| 摘要 |
<p>A hydraulic driving device for a construction machine comprising a first hydraulic pump (1), a second hydraulic pump (2), a plurality of actuators including at least two running motors (4, 7) driven by virtue of pressure oil discharged from these first and second hydraulic pumps and an earth discharging plate elevating cylinder (9), and a plurality of direction control valves including at least two running direction control valves (34, 37) for controlling the flow of pressure oil supplied from the first and second hydraulic pumps to the plurality of respective actuators and an earth discharging plate elevating direction control valve (39), wherein the earth discharging plate elevating direction control valve (39) has a load check valve (53) provided along a feeder line (49) thereof to thereby effect a combined operation of an earth discharging plate (25) elevating and running, the hydraulic device being characterized in that one (37) of the two running direction control valves (34, 37) and the earth discharging plate elevating direction control valve (39) are connected to one (2) of the first and second hydraulic pumps (1, 2) in parallel, that a throttle valve (50) is provided on the upstream side of the load check valve (53) provided at a position along the feeder line (49) of the earth discharging plate elevating direction control valve (39), and that refilling means (51, 52, 54, 3) for refilling pressure oil are provided on the downstream side of the load check valve (53) provided along the feeder line (49) of the earth discharging plate elevating direction control valve (39).</p> |
