HYDRAULIC FLUID CIRCUIT OF HYDRAULIC SHOVEL

摘要

A hydraulic fluid circuit of a hydraulic shovel including a first directional control valve group connected to a first hydraulic pump and including a first directional control valve and a second directional control valve respectively connected to a first hydraulic cylinder and a second hydraulic cylinder. A second directional control valve group, connected to a second hydraulic pump, includes a third directional control valve having a first working port connected to one cylinder chamber of the first hydraulic cylinder and a second working port connected to one cylinder chamber of the second hydraulic cylinder. A switching device in the hydraulic fluid circuit is operative, when the first directional control valve is in a first position to switch the third directional control valve to a first position for supplying hydraulic fluid from the second hydraulic pump to the first hydraulic cylinder through the first working port, and also operative, when the second directional control valve is in a second position, to switch the third directional control valve to a second position for supplying hydraulic fluid from the second hydraulic pump to the second hydraulic cylinder through the second working port.