Hydraulic system with improved complex operation

摘要

The hydraulic system with an improved complex operation includes main hydraulic pumps (1) and a pilot pump; a boom cylinder (18) and an option device; a main control valve (4) including a boom spool and an option device spool which are shifted by a pilot signal pressure from the pilot pump; an operation lever (9) which controls the boom spool; an option operation pedal (10) which controls the option device spool; a confluence spool (7) for controlling the option device; and a controller (3) which outputs an electric control signal to a proportional control valve (20) for the option device so as to delay pilot signal pressure supplied to the confluence spool during start and end of the pilot signal pressure supply when a complex operation for simultaneously operating the boom cylinder and the option device is performed.