| Ball screw pair is widely used in various industrial equipments, precision instruments and precision CNC machine tools for its characteristics of high accuracy, high efficiency, high rigidity, stable running. Although the ball screw pair was applied in the nineteenth century. And a lot of research results have been obtained. But with development of high-speed cutting technology, ball screw pair also has developed in the direction of high-speed. And issues of noise, vibration, motion reliability resulted from high-speed development have been increasingly concerned by researchers.Firstly, according to the position requirement of CNC’s ball screw pair and its structure form and the way of strut, parameterized model is established to reduce unnecessary repetitive modeling work in design process which greatly improved the work efficiency.The causes and characteristics of ball screw pair’s noise are obtained by the analysis of the factors of noise and vibration. The former eight modes and deformation figures are obtained by ANSYS analysis of ball screw and ball screw pair’s nature vibration characristics. Conclusion that the natural frequency and regional deformation of ball screw are reduced by the construction of support and nut is obtained by comparing the differences.And also, conclution that the natural frequency of ball screw pair is changing while running is obtained by the analysis of nut’s different positions on ball screw. According to the results of mode analysis and combining the resources of CNC’s niose and vibration, the method that how to distinguish the natural frequency of ball screw pair is proposed. It can aviod resonance from the same frequency. This has a great guiding significance for the whole feeding system and the system of tool machine.The contact deformation equation of ball screw pair is obtained based on Hertz Contact Theory. The motion reliability analysis of ball screw pair is carried out by Monte Carlo. The distribution pattern of deformation equation can’t be pre-determined. So the random numbers which are called by vc++program are generated by MATLAB. Random sample of each generated parameter is also finished by the program. The results are motion errors of ball screw pair. Count the number of motion errors which are below allowed error. The curve relationship of processing accuracy and motion reliability is obtained finally. And it gives a intuitive reflection of the trend to motion reliability. |
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