Method of controlling the torque developed at a belt shaft of a belt retractor coupled to an electric motor

摘要

The torque developed at a belt shaft of a belt retractor coupled to an electric motor via a drive belt is controlled so as to avoid a hysteresis. For this purpose, the direction of rotation of the belt shaft is detected and, depending on the direction of rotation as detected, the electric current supplied to the electric motor is changed from a first value to a second value that is different from the first value by an amount required to compensate for hysteresis.