抄録
Even if the ball screw is preloaded with a double nut in order to eliminate backlash between the screw shaft and the nut, linear actuators driven by ball screw mechanisms generate non-linear relationships between the linear motion of the nut and the rotary motion of the screw shaft when the ball screw drive is reversed. The behavior of the ball screw mechanism, which is referred to as lost motion, can contribute to positioning errors of linear actuators.
The present paper describes a method by which to calculate the axial stiffness of a ball screw with ball wedging and to determine the lost motion when the ball screw drive is reversed. An attempt is made to evaluate the ball wedging and the lost motion in a preloaded ball screw with a double nut by a comparative study of analytical and experimental results. The lost motion is determined to be produced primarily by the ball wedging. In addition, the effects of internal geometry in the ball screw on the lost motion generated by the ball wedging are analytical investigated based of the calculated results.
