Patent ID: 7484806

Claim:
A seat reclining apparatus for a vehicle, comprising: a first plate attached to one of a seat cushion and a seatback and including internal gear teeth, the first plate provided at one side in a width direction of a seat; a second plate attached to the other one of the seat cushion and the seatback and including external gear teeth engaging with the internal gear teeth of the first plate, a total number of the external gear teeth being smaller than a total number of the internal gear teeth of the first plate, the second plate provided at the one side in the width direction of the seat; a third plate attached to the one of the seat cushion and the seatback and including internal gear teeth, the third plate provided at the one side in the width direction of the seat; a fourth plate attached to the other one of the seat cushion and the seatback and including external gear teeth engaging with the internal gear teeth of the third plate, a total number of the external gear teeth being smaller than a total number of the internal gear teeth of the third plate, the fourth plate provided at the one side in the width direction of the seat; a shaft rotatably supported by the first and third plates; first and second wedge members arranged between the first and second plates and biased in a direction where an amount of eccentricity between the internal gear teeth and the external gear teeth of the first and second plates is increased so as to maintain a position at which the internal gear teeth and the external gear teeth engage with each other; a first cam provided at the shaft and pressing the wedge members to integrally rotate therewith in response to a rotation of the shaft so that the position at which the internal gear teeth and the external gear teeth engage with each other is shifted in a circumferential direction; a support member arranged between the third and fourth plates and engaging with the third plate and the fourth plate when an amount of eccentricity between the internal gear teeth and the external gear teeth of the third and fourth plates reaches a predetermined level; and a second cam provided at the shaft and pressing the support member to integrally rotate therewith in response to a rotation of the shaft; wherein the amount of eccentricity defined by the support member is smaller than the amount of eccentricity defined by the wedge members.