Precision loss modeling method of ball screw pair

摘要

A precision loss modeling method of the ball screw pair was proposed by introducing an effective contact coefficient to consider the intermittent contact between the balls and screw grooves and the parameter in the precision loss model was modified by establishing a multiscale contact mechanics model. The multiscale contact mechanics model between two rough curved surfaces was established by considering the elastic, elastic-plastic, and plastic deformations of contacting asperities to compute such contact parameters as the total actual contact area and contact load. A surface contact coefficient was introduced into the multiscale contact mechanics model to modify the contact parameters by taking the rough curved surfaces of balls and screw grooves into account. The microtopographies of rough surfaces of screw grooves and balls were characterized by the fractal geometry theory, and then the characterization of the microtopography of screw groove surfaces and the multiscale contact mechanics model were unified in the precision loss modeling. Then the relative sliding distance was calculated according to the kinematic analysis of the ball screw. Finally, the precision loss model of the ball screw pair was established by the above analysis. To verify the effectiveness of the precision loss model, the wear test was conducted on a dual-drive ball screw feed drive system under different working conditions. The predicted results agree well with the experimental data in the stable wear stage and the predictive accuracy of the model is much higher than that of previous studies. The effects of such parameters as the axial load and the feed rate on the precision loss were discussed. It is shown that the precision loss increases with the axial load and the feed rate.