Patent ID: 8909438

Claim:
A swing control system for a hybrid construction machine comprising: a swing operation lever; a hydraulic pump connected to an engine; an electric swing motor that makes an upper swing structure swing against a lower driving structure in accordance with an electric control signal corresponding to an operation amount of the swing operation lever; a swing parking brake that is released in accordance with an operation signal of the swing operation lever to drive the swing motor; a control valve which drives a hydraulic cylinder for the swing parking brake by hydraulic fluid from the hydraulic pump to release the swing parking brake if the control valve is shifted by an input of the operation signal from the swing operation lever; and a controller that controls the swing parking brake through shifting of the control valve or controls driving of the swing motor in accordance with the operation signal from the swing operation lever, wherein in the case where the controller controls the driving of the swing motor through detection of an error of an input value by an operation of the swing operation lever or detection of an abnormal output torque value of the swing motor, the controller sets the swing parking brake to stop the swing motor if a swing speed of equipment is low, and the controller repeats setting/releasing of the swing parking brake at predetermined time intervals and then stops the swing motor if the swing speed of the equipment is high.