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The vibration problem of the ball screw feed system in working conditions limits its application in precision machinery. However, few studies have developed models to investigate the vibration mechanism of the ball screw feed system in running status. In this paper, a dynamic model considering travel deviation and ball motion is proposed to explain the vibration mechanism of the ball screw feed system. This model is numerically solved and experimentally verified. Simulation results showed that, the travel deviation mainly affects the vibration amplitude rather than the frequency when the rotation speed is constant. Higher travel deviation introduces higher vibration amplitude, and the vibration of the feed system is more sensitive to the travel deviation of low frequency. • A novel dynamic vibration model of the ball screw system is proposed. • The vibration characteristics of the ball screw feed system is analyzed. • The effects of the rotation speed and travel deviations on the vibration is investigated. • Travel deviations mainly affect the amplitude and offset of vibration. • Travel deviations have a greater impact on the vibration at low frequency. [ABSTRACT FROM AUTHOR]

This study proposes a meticulous friction torque model considering both the asperity interaction and fluid traction mechanisms in micro-scale physical analysis. The fractal theory is employed to characterize the surface roughness in the asperity interaction component. The modification factor is derived to describe the actual contact condition precisely. A dedicated friction coefficient is obtained by fitting experimental data, enabling an accurate characterization of the friction exhibited by the ball screw. The fluid traction component involves the formulation of the modified oil film thickness, achieved by subtracting a modification factor from 1. This model is validated through the experimental data and is more suitable for light to moderate working conditions, contributing to a better understanding and prediction of friction torque. [ABSTRACT FROM AUTHOR]

l An SLD and ASCS model of a preloaded DNBS considering geometric errors are proposed. l An SLD algorithm is proposed for a preloaded DNBS considering non-loaded balls. l The critical external axial force increases with the geometric error l The initial ASCS of a preloaded DNBS decreases with increasing geometric error. l The ASCS can be kept more stable by selecting the appropriate preload. The preloaded double-nut ball screw (DNBS) is widely used in precision transmission for its high load capacity and contact stiffness. However, few researches have been done on the influence of load distribution on the loading performance of a DNBS, and no solution has been found for the problem of non-loaded balls in the raceway. Therefore, we propose a static load distribution (SLD) model of a preloaded DNBS considering geometric errors, which takes into account the influence of non-loaded balls and the interaction between the elastic deformation of a screw/nut and the Hertz contact forces of screw–ball/nut–ball contact areas. This model is verified experimentally. The maximum deviation between the theoretical and experimental values is 6.21%. We numerically simulate the effects of geometric errors on the SLD and axial static contact stiffness (ASCS) of a preloaded DNBS. The SLD varies significantly with the geometric error, preload and external axial forces, and the critical external axial force on the preloaded DNBS increases with the preload and geometric error. For a preloaded DNBS with a given geometric error, the ASCS can be kept more stable by selecting the appropriate preload. [ABSTRACT FROM AUTHOR]