精密滚珠丝杠副预紧力退化机理及预测方法研究

Ball screws, which directly determine the machining accuracy and precision stability of CNC machine tools, are the key part for the CNC machine tools to realize the aim of ‘precise, fast and overloading’. Therefore, studying the degradation mechanism and prediction method of ball-screw preload has great significance for the estimation of health status and remaining life，as well as the improvement of reliability and precision retention of ball screws. Aiming at the difficulties upon obtaining the degradation status of ball-screw preload during working conditions, a novel prediction method of ball-screw preload is presented based on the accurate calculation of the degenerative parameters such as the friction coefficient, wear coefficient and failure threshold. The core idea is to construct the degradation prediction curve of ball-screw preload covering the whole life circle based on the study of starting point, intermediate process and end point of the curve. The research contents mainly include the accurate calculation of ball-screw preload, the degradation mechanism of ball-screw preload based on the accurate calculation of wear coefficient and the modified calculation of failure threshold of ball-screw preload. This project provides a theoretical guidance for the important engineering problems (such as the prolongation of the service life of the ball screw pair and the improvement of the reliability and precision stability) and lays a foundation for the localization of China's high-end CNC machine tools.

滚珠丝杠副作为高档数控机床的核心执行部件，直接决定数控机床加工精度、精度稳定性及保持性，是数控机床实现“精密、快速、重载”的重要保障，研究滚珠丝杠副预紧力退化机理及预测方法，对评估其健康状态、提高其可靠性及精度保持性具有重要意义。本项目针对精密滚珠丝杠副在实际工作过程中预紧力退化状态难以测量的问题，以摩擦系数、磨损系数、失效阈值等参数精确计算为基础研究预紧力退化机理，拟探索一种预紧力退化状态的预测方法体系。其核心思想是通过研究预紧力退化的起点、中间过程及终点，最终构建一条覆盖全生命周期的精密滚珠丝杠副预紧力退化预测曲线。研究内容主要包括滚珠丝杠副预紧力精确计算方法研究、基于磨损模型精确计算的预紧力退化机理研究及预紧力退化阈值计算方法研究。本项目的开展有望为滚珠丝杠副延长使用寿命、提高可靠性及精度保持性等重要工程问题提供理论支撑，为国产滚珠丝杠副产品替代进口、中高档数控机床国产化奠定基础

滚珠丝杠副作为高档数控机床的核心执行部件，直接决定数控机床加工精度、精度稳定性及保持性，是数控机床实现“精密、快速、重载”的重要保障，研究滚珠丝杠副预紧力退化机理及预测方法，对评估其健康状态、提高其可靠性及精度保持性具有重要意义。本项目针对精密滚珠丝杠副在实际工作过程中预紧力退化状态难以测量的问题，以摩擦系数、磨损系数、失效阈值等参数精确计算为基础研究预紧力退化机理，探索出了一种预紧力退化状态的预测方法体系。研究内容主要包括滚珠丝杠副预紧力精确计算方法研究（计算精度较日本NSK公式提升10%）、基于磨损模型精确计算的预紧力退化机理研究（预测误差在6%以内）、预紧力退化阈值计算方法研究（计算误差在7%以内，修正了目前国际通用的卸载状态曲线并给出了新的原理图）、预紧力退化优化策略（优化后的滚珠丝杠副的预紧力衰退量减小了72.4%）。本项目的开展有望为滚珠丝杠副延长使用寿命、提高可靠性及精度保持性等重要工程问题提供理论支撑，为国产滚珠丝杠副产品替代进口、中高档数控机床国产化奠定基础。