Dynamic contact stiffness analysis of a double-nut ball screw based on a quasi-static method

This paper aims to investigate the dynamic contact stiffness characteristics of a double-nut ball screw operating at high speeds. The present study first established a proper transformed coordinate system according to the ball screw mechanism, then a variable contact angle is now considered as a function of the position angle of balls to reflect their dependence on the distribution in the raceway. It goes further to derive a contact stiffness matrix to capture the dynamic behavior of ball screws, which is based on the quasi-static method. The obtained numerical results are validated by experiment. Finally, the 5-dof dynamic model is employed to investigate the distribution of contact angles and normal force varying with the ball screw position angle under different operation condition and structure parameters, and the relation between dynamic contact stiffness and operation condition and structure parameters.