To reduce an operation synchronization failure of recliners on both sides of a seat frame, thereby enabling smoother operation despite variations in the dimensional accuracy of the seat frame. A seat recliner structure includes: recliners which are provided on the left and right sides of a cushion frame and a back frame to recline the back frame relative to the cushion frame; and a connecting rod which connects the left and right recliners to synchronize them, wherein the left and right recliners have different backlashes, and the backlash of the driving-side recliner is smaller than the backlash of the driven-side recliner.

A vehicle-seat-recliner assembly may include first and second recliner hearts, a release handle, a cross-member, a handle pin, a handle-travel-limiter, and a reinforcement member. The release handle is connected with the first recliner heart and is rotatable relative to the brackets to move the first recliner heart between locked and unlocked states. The cross-member is connected to the recliner hearts and transmits torque from the release handle to the second recliner heart to move the recliner hearts between the locked and unlocked states. The handle pin engages the release handle. The handle-travel-limiter may include a flange portion and a shaft portion. The shaft portion may include an aperture configured to receive the cross-member. The flange portion extends radially outward from the shaft portion. The handle pin engages the handle-travel-limiter. The reinforcement member may be fixed to the handle-travel-limiter and the handle pin.

A method for manufacturing a recliner mechanism may include movably attaching a first plate of a recliner heart to a second plate of the recliner heart, positioning a gap ring onto the first plate of the recliner heart, positioning an encapsulation ring around the first and second plates such that the gap ring is disposed axially between the first plate and the encapsulation ring, and removing at least a portion of the gap ring from between the first plate and the encapsulation ring to form a clearance gap between the first plate and the encapsulation ring.

A disc recliner mechanism for use in an automotive vehicle includes a plurality of pawls and a cam mounted between a guide plate and a tooth plate. Rotation of the cam moves the pawls between an extended position in which the pawls engage the tooth plate to lock the disc recliner mechanism and a retracted position in which the pawls disengage the tooth plate to unlock the disc recliner mechanism and allow rotation between the guide plate and the tooth plate. A notch is disposed on an engagement surface of a cam lobe disposed on the cam for reducing friction when the cam lobe engages a cam follower disposed on the pawls. The tooth plate includes a circumferential outer lip with a concentric channel for retaining lubricant and reducing rotational friction between the tooth plate and the guide plate.

Provided is a reclining device that achieves effective prevention of abnormal sound while permitting a clearance to exist between a cam and a connecting rod. A reclining device includes: a pair of reclining mechanisms each having an internal gear and a cam; a connecting rod coaxially coupled to the cam and being rotatable together with the cam; and a resin bush having a fit hole to receive a fitting part at a portion adjacent to each end of the connecting rod. The resin bush is placed in a bush insertion hole in contact with an inner surface of the bush insertion hole of the internal gear to retain the connecting rod at such a position to the cam that a clearance exists between an inner surface of a rod insertion hole of the cam and an outer surface of the connecting rod.

A seat reclining device includes a ratchet, a guide, and pawls for locking relative rotation between the ratchet and the guide. The ratchet has a second convex portion protruding so as to abut against a ride-up protrusion of a main pawl. The second convex portion has, only in a partial region thereof in the rotation direction, a relief concave portion configured to avoid abutment in the rotation direction between the ride-up protrusion and the second convex portion.

A seat for an autonomous driving vehicle includes a cushion part; a back part coupled to a rear end of the cushion part through a recliner and having an adjustable angle in a front and rear direction; and a leg part rotatably coupled to a front end of the cushion part and having a lower side coupled to a seat rail. The back part is disposed to be vertically movable along a back rail located on a rear side of the back part, and the leg part is disposed to be movable back and forth by the seat rail.

A back-rest pivot fitting for a seat, having at least a seat pan, a folding back-rest, which is pivotable coupled to the seat pan, and a pivot fitting. The pivot fitting may have at least a first fitting member which is fixed to the seat pan, a second fitting member, which is pivotable coupled to the first fitting member and which is fixed to the back-rest, a recliner heart and an adjustment member.

A vehicle seat reclining apparatus includes: a protruding portion protruding toward an inner side in a radial direction so as to be abutted by another pawl in a circumferential direction when a specific pawl abuts, in the circumferential direction, against a step formed at a boundary between a first region and a second region; and a restricting portion configured to restrict a movement range of the another pawl regulated by a regulating portion to an inner side in the radial direction than a position where the another pawl and the protruding portion interfere with each other in the radial direction.

A vehicle seat reclining device includes: a ratchet and a guide assembled to be rotatable relative to each other; a plurality of pawls respectively supported by a plurality of corresponding pairs of guide walls of the guide and configured to mesh with the ratchet; and a cam configured to press the pawls in a radial direction by a biasing force of a lock spring. The guide has: welding dowels configured to be welded to a seat frame, the respective welding dowels being formed between the respective pairs of guide walls; and a hooking hole formed between a specific pair of guide walls, an end portion of the lock spring being hooked in the hooking hole. In a state before the welding dowels are welded to the seat frame, a width between the specific pair of guide walls is larger than a width between another pair of guide walls.