A novel calculation expression for the experimental friction coefficient of the ball screw

Abstract

The friction coefficient inevitably affects the friction force between balls and raceway thus might significantly change the performance of the ball screw. However, the traditional methods for determining friction coefficient are based on different empirical values which may lead to different results. To this end, this paper studies the variation law of the friction coefficient by considering different lubrication states between balls and raceway. An experiment is carried out, through which a Stribeck tribology-based expression of the friction coefficient is proposed. The given results provide two obvious stages of lubrication, and the turning point of the two stages represents the minimum value of the friction coefficient. Moreover, the rotational speed is the main factor that influences the value of the friction coefficient based on the calculation of the average central film thickness.