Controlling method of seat belt retractor

摘要

In controlling a seat belt retractor, at least one of signals selected from a state signal showing a movement of an occupant wearing a seat belt and an external signal obtained from detecting means installed in a vehicle during running thereof is received. Then, a rotation of a spool for a webbing is controlled by switching a rotational torque of a motor to a predetermined reduction ratio corresponding to at least one of the state signal and the external signal, or a driving state of the motor is controlled to a predetermined torque, to thereby wind the webbing on the spool.