| 摘要 |
A hydraulic control system for a construction machine is disclosed, which can operate an arm cylinder and a bucket cylinder by supplying hydraulic fluid from respective hydraulic pumps to the arm cylinder and the bucket cylinder during a combined operation, such as an excavating work, in which an arm joystick and a bucket joystick are simultaneously operated. The hydraulic control system includes a first arm control valve installed in a flow path between the first hydraulic pump and the arm cylinder and shifted to control a start, stop, and direction change of the arm cylinder in response to an operation of the arm joystick, a second arm control valve installed in a flow path between the second hydraulic pump and the arm cylinder and shifted to make discharged hydraulic fluid of the second hydraulic pump join hydraulic fluid of the arm cylinder to be supplied if a control signal according to the operation of the arm joystick exceeds a set value, a bucket control valve installed in a path between the second hydraulic pump and the bucket cylinder and shifted to control a start, stop, and direction change of the bucket cylinder in response to the operation of the bucket joystick, and a confluence cutoff proportional valve installed in a path between the second hydraulic pump and the second arm control valve. |
