Analysis of the contact angle of ball screw with Gothic profile considering raceway profile manufacturing error and radial clearance

Abstract

The ball screw is a mechanical linear actuator that translates rotational motion to linear motion with little friction. The elastic contact angle is considered as the key parameter for the ball screw mechanism with Gothic profile, and it is hard to measure this parameter directly. This paper investigates a calculation method for elastic contact angle of the ball screw considering the raceway profile manufacturing error and radial clearance. The method is based on two deformation model of balls under two preload states in ball screw. The deduced formula from the model on free contact angle is found to be identical with results of split inner-ring ball bearing. The effect of the radial clearance and raceway profile manufacturing error are investigated in this paper. The results show that the radial clearance is a key factor affecting the elastic contact angle. The research provides a theoretical basis for error analysis and optimization design of the new type double-nut ball screw mechanism.