Abstract: A seatbelt retractor configured to ease the tightness of a seatbelt felt by an occupant when the occupant wearing the seatbelt reclines a seatback. An acceleration sensor 70 includes a sensor cover 71 which tilts with a seatback, a sensor housing 72 supported swingably with respect to the sensor cover 71 and having an inertial body support surface 78 and an inertial body 73 which is displaced when the acceleration reaches at least a prescribed value. The sensor housing 72 includes an external teeth part 84 having a plurality of external teeth 81 and 82 and a gap part 83 without external teeth.

Abstract: A seatbelt retractor configured to ease the tightness of a seatbelt felt by an occupant when the occupant wearing the seatbelt reclines a seatback. An acceleration sensor 70 includes a sensor cover 71 which tilts with a seatback, a sensor housing 72 supported swingably with respect to the sensor cover 71 and having an inertial body support surface 78 and an inertial body 73 which is displaced when the acceleration reaches at least a prescribed value. The sensor housing 72 includes an external teeth part 84 having a plurality of external teeth 81 and 82 and a gap part 83 without external teeth.

Abstract: A deviation in rotational angle caused between an adjustment gear and a sensor housing is compensated for with a profile of a cable winding groove of a pulley of an attitude control mechanism to accurately synchronize the inclination angle of a seat back and the rotational angle of the sensor housing with each other. Thus, it is possible to keep an inertial element support surface, which serves as a sensor reference surface, accurately horizontal even at any seat back inclination angle to improve the accuracy of an acceleration sensor.

Abstract: A seatbelt retractor includes a rotation transfer mechanism configured to transfer rotation of an adjustment gear to a sensor housing to swing the sensor housing in the front-back direction of a vehicle. The turning axis of the adjustment gear and the swing axis of the sensor housing intersect each other at a predetermined angle with the swing axis of the sensor housing arranged in a horizontal direction with respect to the left-right direction of the vehicle. An inertial element support surface of the sensor housing is kept horizontal by swing motion of the sensor housing in the front-back direction of the vehicle, even if a seat back is tilted in the front-back direction of the vehicle.

Abstract: A deviation in rotational angle caused between an adjustment gear and a sensor housing is compensated for with a profile of a cable winding groove of a pulley of an attitude control mechanism to accurately synchronize the inclination angle of a seat back and the rotational angle of the sensor housing with each other. Thus, it is possible to keep an inertial element support surface, which serves as a sensor reference surface, accurately horizontal even at any seat back inclination angle to improve the accuracy of an acceleration sensor.

Abstract: A seatbelt retractor includes a rotation transfer mechanism configured to transfer rotation of an adjustment gear to a sensor housing to swing the sensor housing in the front-back direction of a vehicle. The turning axis of the adjustment gear and the swing axis of the sensor housing intersect each other at a predetermined angle with the swing axis of the sensor housing arranged in a horizontal direction with respect to the left-right direction of the vehicle. An inertial element support surface of the sensor housing is kept horizontal by swing motion of the sensor housing in the front-back direction of the vehicle, even if a seat back is tilted in the front-back direction of the vehicle.