Study On The Dynamic Characteristics Of Rolling Linear Guide

Rolling linear guide becomes not only a key link component, but also a typical joint surface structure in machine tool because of its high efficient driving, high carrying capacity, low wear and so on. As the joint surface structure being the main cause of vibration and damping, the vibration of rolling linear guide has become a main bar for machine tool development towards higher precision and rapid expansion. In order to subject to this trend, it is imperative to study the dynamic characteristics of rolling linear guide.In this paper, HG-45 rolling linear guide made in ShangYin company is taken as a research subject, and the dynamic characteristics of it is studied in detail using three different methods, which include theoretical analytical modeling method, dynamic test method and finite element modeling method. What's more, the dynamic parameters obtained by these three methods are compared and analyzed in order to ensure the correctness of modeling methods and data. The research contents of the dynamic characteristics of rolling linear guide are as follow.First, structure characteristics of research subject is obtained through the introduction of different types, different structure and different application areas of rolling linear guide. Point to point Hertz contact hypothesis and tangential microscopic slip assumption are used in ball contact characteristics. What's more, according to these assumption, normal and tangential contact stiffness expression can be obtained, which can provide theoretical support for theoretical analysis modeling of rolling linear guide.Secondly, the ball contact is simulated by spring damper element, and equivalent mechanical model of it is established, which includes normal contact stiffness and tangential contact stiffness of it. Dynamic theoretical analysis model and the motion differential equations of rolling linear guide is constructed and derived based on Lagrange equation. When being obtained, the natural frequencies and mode shapes are contrastively analyzed in two situations, considering tangential contact stiffness and not. In addition, the influence of load parameters, material parameters and geometric dimension parameters on the natural frequencies of linear rolling guide are analyzed, respectively.Thirdly, dynamic characteristics test of rolling linear guide is completed by using B&K dynamic test system in order to get real dynamic characteristics parameters of it. Low order natural frequencies and mode shapes obtained by test and theoretical analysis model are compared and the reasons of relative error are analyzed in order to verify the rationality of theoretical model.Finally, dynamic finite element model of rolling linear guide is built, in which the ball contact is simulated by spring damper element. Then, the modal analysis is carried out and the calculation results are compared with that obtained by test and theoretical analysis model in order to verify the rationality of finite element model. In addition, response amplitude of rolling linear guide under different frequencies is obtained, after harmonic response analysis is done based on modal calculation results.The results shows that tangential contact stiffness in ball contact can not be ignored during the research of dynamic characteristics of rolling linear guide; the change of the ball preload is positively correlated with the change of the natural frequency of the system; the response amplitude along Y axis is one order higher than that along Z axis.