Patent ID: 7506832
Filing Date: 2009-03-24
Classification: B60R

Abstract:
1. A motorized retractor comprising: a spool, around which a webbing for restraint of an occupant is wound; a motor capable of rotating in a forward direction and in a reverse direction, the motor including an output shaft; a forward driving force transmission mechanism provided between the spool and the output shaft of the motor, the forward driving force transmission mechanism reducing a forward direction rotation of the output shaft by a predetermined reduction ratio and transmitting the rotation to the spool for rotating the spool in a winding direction, and the forward driving force transmission mechanism blocking transmission of a rotation generated at the spool side thereof to the output shaft; and a reverse driving force transmission mechanism provided between the spool and the output shaft separately from the forward driving force transmission mechanism, the reverse driving force transmission mechanism reducing a reverse direction rotation of the output shaft by a reduction ratio which is lower than the predetermined reduction ratio of the forward driving force transmission mechanism, and transmitting the rotation to the spool for rotating the spool in the winding direction, and the reverse driving force transmission mechanism blocking transmission of a rotation generated at the spool side thereof to the output shaft, wherein the reverse driving force transmission mechanism comprises: a base which is capable of rotation about an axis thereof; a rotor which is integrally coupled with the base and connected with the output shaft of the motor, rotation of the output shaft being transmitted to the rotor for rotating the rotor; a clutch gear which is provided to be relatively rotatable with respect to the rotor and which is connected with the spool, the clutch gear being capable of rotating the spool; a clutch spring provided to be coaxial and relatively rotatable with respect to the clutch gear, a coiling direction one end portion of the clutch spring being coupled with the rotor, and, due to a coiling direction other end portion of the clutch spring moving to one way in the coiling direction, an outer radius dimension of the clutch spring being enlarged for engaging the clutch spring with the clutch gear and causing the clutch gear to rotate integrally with the rotor; a lever provided to be rotatable relative to the base about the axis thereof, the lever being continuously urged one way about the axis of the base, the lever being engaged with the coiling direction other end portion of the clutch spring, and, due to the lever turning to another way about the axis of the base, the lever causing the coiling direction other end portion of the clutch spring to move to the one way in the coiling direction; and a plurality of weights supported at the base to be movable in respective radial directions of the base, the plurality of weights being coupled with the lever, the plurality of weights being retained at inner sides in the radial directions of the base by the lever, and, at a time of rotation of the base by reverse direction rotation of the output shaft, the plurality of weights being moved toward respective outer sides in the radial directions of the base by centrifugal forces which act on the plurality of weights, and causing the lever to turn to the other way about the axis of the base.