| 摘要 |
PROBLEM TO BE SOLVED: To provide a hydraulic system of a construction machine which can enhance the stability of electric negative control.SOLUTION: A hydraulic system 100 for a construction machine which controls a discharge amount of a hydraulic pump 10L according to negative control pressure generated at a negative control throttle 20L comprises: a negative control pressure sensor A1 which detects negative control pressure, and outputs a negative control pressure signal; a pump regulator 40L which controls the discharge amount of the hydraulic pump 10L; and a controller 54 which receives the negative control pressure signal, and outputs a current command to an electromagnetic valve 55L of the pump regulator 40L. The controller 54 has a phase compensation part 540 which compensates a delay in phase progress to the current command, and the phase compensation part 540 changes contents of the delay in the phase progress depending on the case that the negative control pressure is high or the case that the negative control pressure is low. |
