Analysis of contact characteristics of ball screws under the combined loads considering non-uniform load distribution

An analysis model of the contact characteristics of the double-nut preloaded ball screw which can consider the combined action of the axial load and the overturning moment is established, the model can consider non-uniform load distribution, and the validity of the model is verified by experiments. Based on this model, the influence of the combined action of axial load and overturning moment on the average value and distribution fluctuation value of the contact angle of the ball screw, the number of unloaded balls, the distribution fluctuation value of the contact load, and the static contact stiffness and other contact parameters are systematically analyzed, and get the following conclusions: The contact parameters of the ball screw are mainly affected by the axial load and the contact state between the ball and the raceway. The gradually increasing axial load basically reduces the influence of the overturning moment on the contact parameters of the ball screw. There is a critical value of the load in the axial direction within the range of the action value of the preload load. Only when the critical value is above the critical value, the contact parameters will change regularly with the changes in the axial stiffness and overturning moment. However, different critical values for the regular variation of contact parameters with axial load and overturning moment vary.