DIRECT-ACTING ELECTRICALLY-DRIVEN ACTUATOR AND AXIAL FORCE DETECTING MECHANISM OF BALL SCREW USED IN THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a direct-acting electrically-driven actuator provided with an overcorrect protecting mechanism of a motor of low cost. SOLUTION: In this direct-acting electrically-driven actuator, the rotation of a motor 1 is connected with the movement of a ball screw 3 in the axial direction, in such a manner that mutual conversion is possible by using the ball screw 3. A force (axial force) action in the axial direction of the ball screw 3 is replaced with the displacement of springs 8a, 8b. By a specified mount of the displacement, switches 91, 92 are operated, and supply of a winding current is stopped, thereby preventing an overcorrect. Practically, position detecting switches 91, 92 are installed at moving positions of the ball screw end portions which correspond to the allowable value of the motor winding current. According toe the output signals or switches, the power source of the motor 1 is turned off.