HYDRAULIC DRIVE DEVICE FOR LARGE HYDRAULIC EXCAVATOR

摘要

[PROBLEMS] A large size hydraulic excavator that can be easily changed from a state corresponding to a backhoe shovel to a state corresponding to a loader shovel, and vice versa. [MEANS FOR SOLVING PROBLEMS] A hydraulic drive device having a hydraulic circuit (1) provided with hydraulic pumps (11-18) and directional control valves (21-35), solenoid valves (41-43, 51-66) for controlling the hydraulic pumps (11-18) and the directional control valves (21-35), and a controller (70) for controlling the solenoid valves (41-43, 51-66) according to operation of operation lever devices (80-83) and operation pedal devices (84-87). The controller (70) controls the solenoid valves (41-43, 51-66) in a backhoe mode or a loader mode that is selectively commanded by mode command means (71). Controlling the solenoid valves (41-43, 51-66) in the backhoe mode causes the hydraulic circuit (1) to function as a hydraulic drive circuit for backhoe, and controlling the solenoid valves (41-43, 51-66) in the loader mode causes the hydraulic circuit (1) to function as a hydraulic drive circuit for loader mode.