Patent ID: 7607245

Claim:
A construction machine comprising: a first variable displacement hydraulic pump and a second variable displacement hydraulic pump that are driven by a prime mover; a single traveling actuator driven with pressure oil discharged from the first variable displacement hydraulic pump; a plurality of work actuators driven with the pressure oil discharged from at least one of the first variable displacement hydraulic pump and the second variable displacement hydraulic pump; a plurality of control valves that control flows of the pressure oil from the first variable displacement hydraulic pump and the second variable displacement hydraulic pump to each of the traveling actuator and the plurality of work actuators; a traveling command detection device that detects a drive command for the traveling actuator; a work command detection device that detects a work command for an actuator for a work front attachment among the plurality of work actuators; and a flow rate control device that increases a maximum flow rate of the first variable displacement hydraulic pump, wherein the flow rate control device comprises a displacement angle control device that adjusts a maximum displacement angle of the first variable displacement hydraulic pump, and when the drive command for the traveling actuator is detected with the traveling command detection device and the work command is not detected with the work command detection device, the displacement angle control device sets the maximum displacement angle that is larger than the maximum displacement angle set when both the drive command and the work command are detected, and the maximum displacement angle set when the drive command is not detected.