Abstract: A construction machine includes an attitude sensor that detects the current attitude of an upper turning body; a reference angular acceleration calculation unit that calculates a reference angular acceleration to be generated when an electric turning motor is driven by a torque command value generated according to the operation amount of an operation part; a reference gravity torque calculation unit that, on the basis of the current attitude and the deviation between an actual angular acceleration, calculates a reference gravity torque; a gravity compensation torque calculation unit that calculates a gravity compensation torque for compensating a torque component generated about the turning axis by the gravity in the current attitude; and a correction unit that corrects the torque command value by using the gravity compensation torque so as to cancel the torque component generated about the turning axis by the gravity in the current attitude.

Abstract: The present invention discloses a configuration for cooling both an electric motor as a drive source and a device for supplying electric power to the electric motor using a cooling medium such as water with a view to achieving efficient cooling without any cost increase. The present invention comprises: an electric motor serving as a drive source; a power feeder for supplying electric power to the electric motor from outside; a cooling flow channel through which coolant water is circulated for cooling the electric motor and the power feeder; and a radiator which cools the coolant water flowing through the cooling flow channel.

Abstract: This construction machine comprises: an attitude sensor that detects the current attitude of an upper turning body; a reference angular acceleration calculation unit that calculates a reference angular acceleration to be generated when an electric turning motor is driven by a torque command value generated according to the operation amount of an operation part; a reference gravity torque calculation unit that, on the basis of the current attitude and the deviation between an actual angular acceleration which is obtained from a rotation speed and the reference angular acceleration, calculates a reference gravity torque which is a torque component to be generated about the turning axis by the gravity in the reference attitude; a gravity compensation torque calculation unit that, on the basis of the reference gravity torque and the current attitude, calculates a gravity compensation torque for compensating a torque component generated about the turning axis by the gravity in the current attitude; and a correctio

Abstract: The hydraulic apparatus is set so that the ratio of the pressure-receiving area of the respective bottom oil chambers of the boom cylinder, the arm cylinder and the bucket cylinder to the pressure-receiving area of the respective rod oil chambers matches the ratio of the extruded volume drawn into or discharged from the bottom oil chambers per single rotation by the respective extrusion members of the first hydraulic pump motor, the second hydraulic pump motor and the third hydraulic pump motor to the volume discharged from or drawn into the rod oil chambers.

Abstract: The hydraulic apparatus is set so that the ratio of the pressure-receiving area of the respective bottom oil chambers of the boom cylinder, the arm cylinder and the bucket cylinder to the pressure-receiving area of the respective rod oil chambers matches the ratio of the extruded volume drawn into or discharged from the bottom oil chambers per single rotation by the respective extrusion members of the first hydraulic pump motor, the second hydraulic pump motor and the third hydraulic pump motor to the volume discharged from or drawn into the rod oil chambers.

Abstract: An engine heat pump whose compression work is reduced without increase of consumed electric power, thereby improving its driving efficiency (energy efficiency). An engine heat pump comprises: an engine; a main compressor driven by the engine; a sub compressor delivering a refrigerant to be joined to a refrigerant delivered from the main compressor; an indoor heat exchanger; an outdoor heat exchanger; an expansion valve for the indoor heat exchanger; an expansion valve for the outdoor heat exchanger; and a supercooling heat exchanger disposed on a liquid refrigerant passage (main passage) of a connection passage between the indoor heat exchanger and the outdoor heat exchanger. In the supercooling heat exchanger, a supercooling liquid refrigerant branched into a branching passage supercools a liquid refrigerant before being branched. The sub compressor is driven by the engine so as to compress the supercooling liquid refrigerant.