Optimization of Axial Contact Stiffness of Precision Ball Screws Based on Hertzian Theory

The maximum axial contact stiffness optimization model of double-nut ball screws was established. The coupling association of the normal force of raceway with the variation of the contact angle based on Hertzian theory was considered. The optimal axial contact stiffness can be determined by using ISIGHT integrated MATLAB with the NLPQL (quadratic sequence planning method) method in terms of the contact angle and curvature ratio. The results showed that within a specified range with a gradually increasing curvature ratio, the contact angle increased, whereas ball screw axial contact stiffness first increased and then decreased. The axial contact stiffness was increased by 13.3% after optimization.