Patent ID: 7195318

Claim:
A reclining device of a vehicle seat comprising: a lower plate fixed to an inner end of a cushion frame of the vehicle seat; an upper plate fixed to a lower end of a seat back; an actuator disposed in a space between the lower plate and the upper plate; a recliner shaft, an actuating lever, and a lever spring serving as an actuating means, and coupled to an outer side of the lower plate; and the actuator including: a lock gear having locking teeth engaged with upper teeth formed at the upper plate; a cam coupled to a recliner shaft to push the lock gear to engage the upper teeth with the locking teeth; a lock guide, integrally formed with the lower plate, for guiding the lock gear; a locking means, disposed to the lock gear and the cam, for maintaining the engagement of the upper teeth with the locking teeth and for separating the upper teeth from the locking teeth; a locking and releasing means having a release recess formed at a lower side of the lock gear, and a release protrusion formed at the cam coupled to the recliner shaft, the release recess and the release protrusion being engaged with each other; a lower side of the lock gear stably supported by a main supporting point, defined by which an arc-shaped guide recess at one side of the release recess makes contact with an upper side of the release protrusion of the cam, and an auxiliary supporting point, defined by which the lock gear make contact with a protruded portion, opposite to the release protrusion, of the cam; a lower side of the release protrusion including: an initial operative surface, having a slope, for generating a considerable torque in an initial state to easily separate the lock gear firmly engaged with the upper teeth; an intermediate operative surface formed at a lower side of the initial operative surface and having a larger slope than the initial operative surface; a final operative surface, formed at a lower side of the intermediate operative surface, for fully separating the lock gear; the initial operative surface, the intermediate operative surface, and the final operative surface making contact with an actuating protrusion, protruded from a lower side of the release recess of the lock gear to the release protrusion, to lower and release the lock gear, wherein the actuating protrusion includes a frictional tip, formed at one end of the actuating protrusion, and having a short linear portion downwardly inclined and rounded to minimize friction.