Hybrid construction machine

摘要

Provided is a hybrid construction machine (driving the upper swing structure using a hydraulic motor and an electric motor together) capable of regenerating the energy of the upper swing structure in deceleration or stopping into electric power and using the regenerated electric power for assisting the driving of the upper swing structure, while also being capable of securing satisfactory operational feeling and operation capability even when the electric motor does not operate. When the electric motor is not driven, a controller controls a hydraulic circuit system (specifically, a swing direction/flow rate control valve, a center bypass cut valve and a regulator) so as to increase output torque of the hydraulic motor by an amount corresponding to torque to be compensated for the non-driving of the electric motor compared to cases where the electric motor is driven.

主权项

1. A hybrid construction machine comprising:
a lower travel structure; an upper swing structure which is mounted on the lower travel structure to be capable of swinging; a hydraulic circuit system which includes a swing hydraulic motor driving and swinging the upper swing structure, a hydraulic pump supplying hydraulic fluid to the swing hydraulic motor, a tank receiving the hydraulic fluid returning from the swing hydraulic motor and serving as the source of supply of the hydraulic fluid to the hydraulic pump, and a direction/flow rate control valve arranged in a line connecting the hydraulic pump and the swing hydraulic motor and controlling the direction and the flow rate of the hydraulic fluid discharged from the hydraulic pump and supplied to the swing hydraulic motor; a prime mover which drives the hydraulic pump; a swing electric motor which drives and swings the upper swing structure in an auxiliary manner, the swing electric motor functioning as an electric generator when the swinging of the upper swing structure is decelerating; an electricity storage device which receives and supplies electric energy from/to the swing electric motor; and a control device which controls the operation of the swing electric motor, wherein: when the swing electric motor is not driven, the control device controls the hydraulic circuit system so as to increase output torque of the swing hydraulic motor by an amount corresponding to torque to be compensated for the non-driving of the swing electric motor compared to cases where the swing electric motor is driven.