Construction machine

A construction machine comprising:

• a machine body;
• a front work implement attached to the machine body;
• a first hydraulic pump and a second hydraulic pump mounted in the machine body;
• a first hydraulic actuator that is driven by a delivered fluid of the first hydraulic pump and drives the front work implement;
• a second hydraulic actuator that is driven by a delivered fluid of the second hydraulic pump and drives the front work implement;
• a third hydraulic actuator driven by the delivered fluid of the second hydraulic pump;
• a directional control valve that controls a flow of a hydraulic fluid supplied from the second hydraulic pump to the second hydraulic actuator;
• solenoid valves that generate a pilot pressure that drives the directional control valve;
• an operation device for operating the front work implement;
• a sensor that senses a state amount corresponding to action of the third hydraulic actuator;
• and
• a controller that controls the solenoid valves, the first hydraulic pump, and the second hydraulic pump on a basis of a target face distance that is a distance between a specific point in the front work implement and a target construction face that is set in advance and an operation signal according to operation of the operation device, wherein
• the controller is configured to
• compute a supply flow rate of the hydraulic fluid supplied from the second hydraulic pump to the third hydraulic actuator, on a basis of an output of the sensor,
• compute an upper limit speed of the second hydraulic actuator on a basis of a flow rate difference between a maximum flow rate at which the second hydraulic pump is capable of delivering and the supply flow rate supplied to the third hydraulic actuator,
• compare a required speed of the second hydraulic actuator according to the operation signal with the upper limit speed,
• compute the required speed as a target speed of the second hydraulic actuator when the required speed is equal to or lower than the upper limit speed, and compute the upper limit speed as the target speed when the required speed exceeds the upper limit speed,
• add the supply flow rate supplied to the third hydraulic actuator to a flow rate according to the target speed of the second hydraulic actuator to compute a target flow rate of the second hydraulic pump, and
• control the solenoid valves on a basis of the target speed and control the second hydraulic pump on a basis of the target flow rate.