A deceleration device for a vehicle seat comprises an external gear comprising teeth with tops projecting radially outward. A tooth of the external gear comprises a straight portion and a critical cross-section located in a dedendum flank of the tooth of the external gear. The straight portion is provided in a vicinity of the critical cross-section and a thickness of the straight portion becomes linearly larger toward a root of the tooth.

A bracket for attaching an actuator is easily bonded to a side frame while avoiding interference with a shaft for driving a reclining mechanism. In a seat side frame which is provided at each of both ends of a seat back frame in the width direction, a reclining mechanism, and an actuator, the reclining mechanism is attached to a side wall of the side frame, and the actuator is fixed to an attachment bracket bonded to an inner surface of a portion to which the reclining mechanism is attached in the side wall in the width direction. An upper portion which is disposed above the attachment portion of the reclining mechanism and a lower portion which is disposed below the attachment portion thereof are connected to each other at the rear ends thereof and are separated from each other at the front ends thereof.

A vehicle seat includes a seat bottom and a seat back coupled to the seat bottom and configured to move relative to the seat bottom. A reclining assembly is coupled to the seat bottom and the seat back to move the seat back relative to the seat bottom.

A brake device comprises a brake mechanism which comprises an output shaft having a drive gear secured thereto, a brake housing having a cylindrical braking surface therein and coaxially putting therein the output shaft, two pairs of clamp members movably and abreast installed in the brake housing in such a manner that paired two clamp members of each pair put therebetween an enlarged operation part of the output shaft and two springs that bias the two clamp member of each pair to pivot away from each other, in which each of the clamp members has an outer clamp surface that is slidably contactable with the cylindrical braking surface and includes larger and smaller clamp surface areas that are spaced from each other by a recess.

A hinge mechanism having first and second hinge flanges, a control device controlling the relative rotation of the first and second hinge flanges, a closure ring integrally secured to the second hinge flange and retaining the first flange against the second flange, and an external frame integrally secured to the second flange. The second hinge flange is integrally secured to both the external frame and the retaining ring by the same weld.

A recliner for a vehicle seat includes a first gear having a center hole provided at a center thereof, a second gear being internally in contact with the first gear and configured to eccentrically engage with the first gear, a socket having a coupling portion configured to be coupled to the center hole, and a pair of wedge cams disposed between the socket and the second gear and configured to restrain or release the socket and the second gear.

Device for connecting a region, which is lower when viewed in the vehicle seat height direction, of a backrest to a region, which is rear when viewed in the vehicle seat length direction, of a seat part of a vehicle seat, a tilt adjustment device which is rotatable about a first axis of rotation extending in the vehicle seat width direction for adjusting a tilt of the backrest relative to the seat part being connected to the seat part, wherein the device comprises an adapter element which is rigidly connected to the tilt adjustment device and is rotatable about the first axis of rotation, which element has a first recess which extends at a first angle to a backrest length direction, the first recess being able to be connected to a first tab which is arranged on the backrest and is formed so as to be complementary to the first recess.

Device for connecting a region, which is lower when viewed in the vehicle seat height direction, of a backrest to a region, which is rear when viewed in the vehicle seat length direction, of a seat part of a vehicle seat, a tilt adjustment device which is rotatable about a first axis of rotation extending in the vehicle seat width direction for adjusting a tilt of the backrest relative to the seat part being connected to the seat part, wherein the device comprises an adapter element which is rigidly connected to the tilt adjustment device and is rotatable about the first axis of rotation, which element has a first recess which extends at a first angle to a backrest length direction, the first recess being able to be connected to a first tab which is arranged on the backrest and is formed so as to be complementary to the first recess.

A bracket for attaching an actuator is easily bonded to a side frame while avoiding interference with a shaft for driving a reclining mechanism. In a seat side frame which is provided at each of both ends of a seat back frame in the width direction, a reclining mechanism, and an actuator, the reclining mechanism is attached to a side wall of the side frame, and the actuator is fixed to an attachment bracket bonded to an inner surface of a portion to which the reclining mechanism is attached in the side wall in the width direction. An upper portion which is disposed above the attachment portion of the reclining mechanism and a lower portion which is disposed below the attachment portion thereof are connected to each other at the rear ends thereof and are separated from each other at the front ends thereof.

A recliner heart includes a first locking plate, a second locking plate, a hub, a pair of wedges, a first biasing member, and a second biasing member. The first locking plate includes first teeth. The second locking plate is rotatable relative to the first locking plate and includes second teeth. The first biasing member is configured to apply a first biasing force to the wedges. The second biasing member is configured to apply a second biasing force to the wedges. The hub is rotatable between a first position in which the first and second biasing forces are applied to the wedges to restrict rotation of the second locking plate relative to the first locking plate, and a second position in which the first biasing force applied to one wedge of the wedges is reduced to allow rotation of the second locking plate relative to the first locking plate.