Seat belt device

Motor vehicle seat belt arrangement has a seat belt (11), belt roller (13) and drive. The drive comprises an electric motor (15) that has a mechanical energy store (17) coupled to it. The motor can be operated in a storage mode, where it is decoupled from the roller and supplies energy to the mechanical energy store, or in winding mode in which motor and mechanical energy store apply a torque to the winder mechanism to wind-in, i.e. tighten the belt. A control unit controls the motor operating mode.