HYDRAULIC SYSTEM OF CONSTRUCTION MACHINE

摘要

The present invention relates to a hydraulic system of a construction machine. A hydraulic system of a construction machine according to the present invention includes: an EPPRV (60, Electronic Proportional Pressure Reducing Valve) for controlling a flow rate, to which maximum pressure is input as a control current value and which is set to a minimum flow rate; a gear pump (70) for providing pilot operation oil to the EPPRV (60); a shuttle valve (80) for comparing the pressure of first pilot operation oil which has passed through the EPPRV (60) and the pressure of a flow rate control signal and then outputting second pilot operation oil of greater pressure; a hydraulic pump (10) of which swash plate angle is controlled by the second pilot operation oil; and a pump control device (50) for controlling the pressure of the EPPRV (60) to be reduced from the maximum pressure according to a set inclination if the flow rate control signal is generated.