Patent attributes
A seat reclining device includes a base member formed with a shaft hole; a rotating member including an internal gear; at least three lock members each including an external gear; a shaft portion formed integrally with the base member and including a convex guiding surface for swinging the lock member along a circular orbit; a cam provided with an axially projecting portion passing through the shaft hole; and at least three guide projections formed integrally with the base member. The axially projecting portion includes a centering outer peripheral surface which is slidably in contact with an inner peripheral surface of the shaft hole. The guide projections and the lock members are located alternately in the circumferential direction. Each of the guide projections includes a centering inner peripheral surface provided at inner peripheral side of the guide projection and adapted to slide on an outer peripheral surface of the cam to perform a centering of the cam; and a pair of concave guiding surfaces respectively guiding the adjacent two lock members so as to swing the adjacent two lock members along the circular orbits.