Numerical investigation into dynamic behavior of adjustable preload double-nut ball screw

The dynamic behavior of a double-nut ball screw was investigated by means of ABAQUS 6.13A (c) simulations based on a threedimensional model. The validity of the numerical model was demonstrated by comparing the simulation results obtained for the reaction force and torque acting on the flange of the nut with the experimental results. We found that the two sets of results deviated by no more than 5.87% given a screw rotating speed of 100 rpm. Simulations were performed to investigate the effects of the spacer width, screw rotating speed, steel ball radius and axial force on the torque acting on the nut flange. The results show that the torque increases with an increasing spacer width due to an increasing preload force. Moreover, the torque increases as the screw rotating speed increases to 700 rpm, but decreases at higher rotating speeds due to a greater centrifugal force. Ball wear prompts a reduction in the preload force and thus reduces disproportionately the torque acting on the flange following extended operation. For higher axial loads (> 100 N), the torque remains approximately constant during run-in (0.025 similar to 0.2 s). However, for lower loads, notable fluctuations in the torque occur.