Seat reclining device

摘要

The seat reclining device is structured that a first circular shaped concave portion is formed in the first arm and a second concave portion which is concentric with the first concave portion is formed in an inner surface of the first concave portion respectively. The engaged portion is disposed by dividing into two engaged portions in which a first engaged portion is formed on an inner surface of the first concave portion and a second engaged portion is formed on an inner surface of the second concave portion. On the other hand, the engaging portion is divided into two engaging portions, in which a first engaging portion is engaged with the first engaged portion and a second engaging portion is engaged with the second engaged portion. All the engaging and engaged portion have gears which has the same angular piths each other.