Patent ID: 8348806

Claim:
A construction machine comprising: an electric motor/generator coupled to an electricity accumulator and configured to generate a torque; an engine configured to generate a torque; a transmission coupled to drive wheels and configured to shift between plural gear positions; an epicyclic gearing configured to couple an output shaft of the electric motor/generator, an output shaft of the engine, and an input shaft of the transmission, the torque generated by the electric motor/generator and/or the engine being transmitted to the drive wheels to enable the construction machine to drive; a clutch configured to directly couple two among the output shaft of the electric motor/generator, the output shaft of the engine, and the input shaft of the transmission; and a controller configured: to, under a condition in which the clutch is in an off-state, control engine speed of the engine based on the degree to which an accelerator is open and on the amount of electricity in the electricity accumulator, to control shifting of the transmission gear position based on the accelerator opening degree, an operational state of the electric motor/generator, and the amount of electricity in the electricity accumulator, and to determine the torque generated in the engine and the torque generated in the electric motor/generator, based on the accelerator opening degree, vehicle speed of the construction machine, and the transmission gear position.