| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent speed variation of a particular actuator from changing its speed by supplying pressure oil preferentially to it even if the saturation state of the amount of pump discharge occurs, to maintain the priority for the actuator irrespective of settings of the engine speed and to realize good operability, in a hydraulic driving device having an LS system. SOLUTION: A differential pressure reducing valve 11 is provided to output differential pressure between discharge pressure of a hydraulic pump 2 and the maximum load pressure of actuators 3a, 3b, etc., as an absolute pressure. Also a differential pressure reducing valve 51 is provided to output pressure according to the engine speed as an absolute pressure. Target compensation differential pressure is set by introducing the output pressure of the valve 11 to non-slewing pressure compensation valves 7b and 7c, whereas target compensation differential pressure is set by introducing the output pressure of the valve 51 to a slewing pressure compensation valve 7a. A limiter 91 is provided in a pump inclination rolling variable mechanism 90 of a pump inclination rolling control mechanism 12. The limiter 91 sets the minimum discharge amount of a hydraulic pump 2 to the largest requested flow rate for slewing or more.</p> |
