Analysis on load-bearing performance of ball screw pair considering unloaded zones

Abstract:

To achieve a more accurate load distribution for ball screw pair with internal circulation and optimize structural parameters of ball screw pair to enhance load-bearing performance, this study established a novel load distribution computation model. Building upon the traditional continuous load distribution model, the proposed approach incorporated the unloaded zone induced by reversers. First, ball-nut and ball-screw contact models were established. Based on the deformation compatibility mechanism between balls and raceways, the continuous load distribution model was derived. Second, the spatial position distribution of the ball chain was determined according to the ball return curve. On this basis, a load distribution solution method for ball screw pair considering balls in unloaded zones was proposed. By using this method, quantitative comparisons were conducted between the proposed model and the traditional continuous load distribution model regarding full-ball loads and contact stresses. The effects of the number of reversers and different ball diameters on key load-bearing characteristics, such as contact loads and static stiffness, were thoroughly analyzed. Finally, static loading experiments were conducted to validate the accuracy of the proposed load distribution model. Experimental results show that the maximum error in axial contact deformation between the proposed model and experimental measurements is 5.42%, and the maximum error in static stiffness between them is 6.69%, confirming the proposed model’s accuracy. Compared to the traditional model, the proposed model exhibits higher agreement with experimental results, providing a method for the precise design of ball screw pair.