Patent ID: 7665704

Claim:
A seat rail apparatus, comprising: a lower rail member fixed to a floor face of a vehicle and an upper rail member fixed to a seat of the vehicle, the upper rail member being slidable with respect to the lower rail member; a screw disposed along the longitudinal direction of either one of the lower rail member and the upper rail member, the screw having a lead angle and a self-locking angle of friction, wherein the screw's lead angle is larger than its self-locking angle of friction; a nut fixed to the other one of the lower rail member or the upper rail member and screwed with the screw; and a lock mechanism capable of arbitrarily locking the rotation of the screw provided to the rail member disposed with the screw; the seat rail apparatus being capable of, when the lock mechanism locks the rotation of the screw, holding the upper rail member at an arbitrary position to restrict the forward/backward sliding with respect to the lower rail member, wherein the screw is provided with a brake disk on the same axis thereof, the lock mechanism is provided with a rolling member, a force imparting member for imparting a force to the rolling member in a specific direction and a supporting member for holding the same, the rolling member and the force-imparting member are disposed on the periphery of the brake disk, the force-imparting member imparts the force to the rolling member in the periphery direction, and the supporting member is disposed with the force-imparting member and the rolling member therein, the rolling member, being imparted with the force by the force-imparting member, is sandwiched between the brake disk and the supporting member and engaged with friction therewith, and by means of the friction engagement, the rotation of the screw can be locked, and in order to lock the rotation of the brake disk in the clockwise/counterclockwise direction, at least one rolling member is disposed for each direction, the lock mechanism is provided with an operating member for releasing the rolling member from the friction engagement to release the lock of the screw.