摘要 |
PROBLEM TO BE SOLVED: To provide a smoothening processor for a ball nut that can restrain the effect of a drive screw to increase the torque of a motor owing to the wear of the drive screw and to provide a smoothening method.SOLUTION: A control rod driving mechanism comprises a drive screw rotated by the rotational motion of a motor, a ball nut intervening around the outer circumference of this drive screw, a hollow piston that is moved up and down by this ball nut, and a control rod linked to this hollow piston. The drive screw, intended for use in an underwater environment, is installed in a perpendicular state relative to the ground surface; the ball nut is mounted with a weight of a prescribed level of heaviness; and the running plane of the drive screw is smoothened by moving the ball nut up and down a prescribed number of times. |