METHOD FOR DETECTING DECREASED PRELOAD IN BALL SCREW AND LINEAR MOTION DRIVE DEVICE

摘要

A linear motion drive device including a ball screw, a linear motion table driven by the ball screw to move linearly, and an abnormality detection device configured to detect a decrease in a preload applied to the ball screw. The abnormality detection device includes a vibration sensor configured to measure vibration during operation of the ball screw, a calculation processing unit configured to acquire a vibration value of a vibration signal in a specific frequency band among vibration signals measured by the vibration sensor, and an abnormality detection unit configured to determine that a decrease in the preload has occurred in the ball screw when the vibration value is less than a previously determined threshold with respect to a reference value, the reference value being a vibration value in an initial stage of the operation of the ball screw or during a normal operation of the ball screw.