Performance evaluation of a novel ball screw raceway profile based on geometric close contact theory

Abstract

The raceway profile greatly influences the performance of a ball screw. Although the traditional circular raceway profile is simple in structure, it can be a limitation to the load carrying capacity of ball screws. In this paper, a novel type of ball screw raceway profile is proposed based on geometrical close contact theory. Firstly, the second-order approximation curve of the ball is derived using the McLaughlin formula in the normal plane of the raceway helix, which serves as the basis for constructing the close raceway profile. The mathematical expression of the contact stress distribution of the close raceway is then obtained using Chebyshev polynomials. A comparison and analysis of the contact stress distribution between the close raceway and the conventional raceway is carried out. Furthermore, simulation models of ball screws with the close raceway profile are established and the contact behavior of the ball with both types of raceways is statically simulated using ANSYS software. The dynamic performance of both ball screws is compared and analyzed using ADAMS software. The analysis results show that compared with the conventional raceway ball screw, the close raceway ball screw has lower stress, strain, and friction torque under the same load conditions. These research results have significant implications for the structural optimization of ball screws.