Patent ID: 8240449

Claim:
A locking device of a rotary shaft comprising: a clutch member rotating integrally with the rotary shaft and provided so as to be displaceable in a direction of axis of the rotary shaft; a locking member provided in a fixed state to engage the clutch member to regulate the rotation of the clutch member; a biasing member biasing the clutch member toward the locking member; and a torque transmission member rotating under a rotary torque transmitted thereto from a power source, having a boss loosely inserted into a cam groove provided in an outer peripheral portion of the clutch member, and transmitting the rotary torque to the clutch member via the boss, wherein the boss is displaced within the cam groove with switching of a rotation/stop of the torque transmission member or switching of the rotational direction thereof, to switch between an unlocked state where the boss separates the clutch member from the locking member against the biasing force of the biasing member, and a locked state where the boss permits displacement of the clutch member to engage the locking member with the clutch member, wherein an engaging portion between the locking member and the clutch member is constituted by meshing teeth, wherein the tooth profile of the meshing teeth is set such that a pressure angle δ 1 with respect to one rotational direction of the clutch member is 0°<δ 1 <90°, and a pressure angle δ 2 with respect to the other rotational direction is 0°.