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.

预紧双螺母滚珠丝杠（DNBS）因其高承载能力和接触刚度而广泛应用于精密传动。然而，关于载荷分布对DNBS加载性能影响的研究很少，也没有找到解决滚道中滚珠未加载问题的方法。因此，我们提出了一种考虑几何误差的预加载 DNBS 的静载荷分布 (SLD) 模型，该模型考虑了未加载滚珠的影响以及丝杠/螺母的弹性变形与丝杠赫兹接触力之间的相互作用。 -球/螺母-球接触区域。该模型已通过实验验证。理论值和实验值之间的最大偏差为 6.21%。我们数值模拟了几何误差对预加载 DNBS 的 SLD 和轴向静态接触刚度 (ASCS) 的影响。SLD随几何误差、预紧力和外轴力变化显着，预紧DNBS上的临界外轴力随预紧力和几何误差而增大。对于具有给定几何误差的预加载 DNBS，通过选择适当的预加载，ASCS 可以保持更稳定。