Improvement of the Critical Speed of the Ball Screw Mechanism by Using Flexible Supported Nut

The ball screw with a long stroke has small rigidity in radial direction and is very liable to resonate dramatically during operation at high speed. For improving the critical speed of the ball screw, this paper investigates the influence of the supporting stiffness of the screw shaft at the nut on the resonance frequency of the screw shaft in the radial direction. The screw shaft is modeled as an Euler-Bernoulli beam with elastic supports at both ends and the position of the nut. According to the established model, the relationship between the natural frequencies and the supporting stiffness of the shaft at the nut can be obtained. The simulation results show that the flexible support at the position of the nut can effectively increase the minimum natural frequencies and reduce the variation range of the natural frequencies over the travel range of the nut. It is conducive to the vibration suppression and the critical speed improvement of the ball strew