Independent flow rate controlling hydraulic system for pressure control of excavator and independent hydraulic pressure controlling method using the same

An independent flow rate controlling hydraulic system for pressure control of an excavator, the hydraulic system comprising:

• a plurality of actuators (10) which actuate a working apparatus;
• a pressure control-type hydraulic pump (20) which feeds working fluid to the actuators (10);
• first and second electronic proportional control valves (41, 42) which are disposed at a piston-side inlet flow path (31) and a load-side inlet flow path (32) connected from the hydraulic pump (20) to the actuators (10);
• third and fourth electronic proportional control valves (43, 44) which are disposed at a piston-side outlet flow path (33) and a load-side outlet flow path (34) connected from the actuators (10) to a hydraulic tank (50);
• and
• a control unit (70) which variably controls areas of the flow paths by controlling the first, second, third and fourth electronic proportional control valves (41, 42, 43, 44) connected to the actuators (10) depending on an amount by which a control stick (60) is manipulated,
• wherein the areas of the flow paths are variably controlled by the first, second, third and fourth electronic proportional control valves depending on the amount by which the control stick is manipulated.