Study on the load distribution of ball screws with errors

A model is developed to analyze the load distribution of ball screws with geometry errors. The load distribution of the contact of the balls and grooves is theoretically investigated under various load conditions. The results demonstrate that the negative geometry errors of the ball screw result in the decrease of the load on balls or guiding grooves, and when the negative errors reach certain value there is no contact between the balls and the groove. On the other hand, if geometry errors of the ball screw are positive, the load increases. If the error heights are assumed to be a normally random distribution, the load distribution without geometry error is the average value of that in random error. It is valuable for equilibrating the load distribution to correct nut grooves. The simulation results show that the model proposed in this paper is significant to the study of the characteristics of ball screws with regard of geometry errors.