Patent ID: 7870768

Claim:
A power steering lock unit comprising: a lock bolt which is movable between a lock position, at which the lock bolt engages a steering shaft, and an unlock position, at which the engagement is released; an actuator for moving the lock bolt; a transmission mechanism for transmitting a drive force of the actuator to the lock bolt and thus moving the lock bolt between the lock position and the unlock position; and a position detection mechanism for detecting a movement position of the lock bolt, wherein the transmission mechanism includes a rotation gear arranged to move the lock bolt between the unlock position and the lock position, a cam member linked to the lock bolt, a cam groove provided on one of the rotation gear and the cam member, the cam groove forming a substantially spiral path so as to convert a rotational movement of the rotation gear to a linear movement of the lock bolt via the cam member, the cam groove being centered around a center of rotation of the rotation gear, and a cam follower provided on the other of the rotation gear and the cam member, the cam follower being arranged to slidably move in the cam groove, wherein the position detection mechanism includes a movable member to which a magnet is fixed, a base plate on which a magnetic detection means for detecting a magnetic force of the magnet is disposed, and a holder for holding, in an operable manner, the movable member at a prescribed spacing from the base plate, wherein the rotation gear includes an operating portion and the movable member includes a receiving portion, and a linking mechanism is provided for by abutting the operating portion on the receiving portion so as to operate the movable member in an interlocked manner with operation of the rotation gear, wherein a play is provided between the operating portion and the receiving portion such that the movable member is arranged to move, after a prescribed time delay, in response to the movement of the rotation gear, and wherein the magnetic detection means is arranged to detect the force of the magnet of the movable member so as to determine the movement position of the lock bolt via the movable member and the transmission mechanism.