Research On Static Stiffness Modeling And Dynamic Characteristics Analysis Of Linear Rolling Guide

Linear motion rolling guide have many advantages compared with conventional sliding guide. In recent years, therefore, linear rolling gudie have been widely used instead of sliding guide for hige-precision postioning systems in application such as CNC machine tools, measuring systems, and transporting systems. With the increasing requirement of the high-precision machine, in order to achieve the high-speed and high-precision positioning, the static and dynamic behaviors of linear rolling guide must be sufficiently understood in the design stage for a CNC machine.Studies have shown that the interfaces of linear rolling guide have signicant influence on the dynamic behaviour of machine tools due to creation of stiffness and damping. However, the processing of interfaces has been the key problems to influence the dynamic design and simulation accuracy in the dynamic modeling of machine tools. The tested linear rolling guide in this paper were linear guideway type "radial" rolling guide and produced by THK CO., LTD. Based on the static analysis results in FEM software ANSYS, new calculation formulas of static stifness is proposed. Influence of movable joint and bolted interfaces on dynamic characteristic of linear rolling guide is analyzed by using theory calculation、FEM method and experimental modal analysis.The main contents of this peper is as following:(1) This article describes the dynamic modeling methods of linear rolling guide. Research method combined with theoretical research, dynamic test and finite element analysis is proposed.The solid modeling methods of bolt and its interfeces between bolt and rail are also summarized. Besides,some typical modeling metods were created and compared with simulation results. The related parameters of bolted interfaces is obtained.(2) Based on the calculation formulas of static stifness proposed in this paper, contact analysis on radial type LRG produced by THK is made, and normal and tangential stiffness is obtained. (3) Dynamic vibration model and FEM of LRG including movable joint and bolted joints are established. The first5-order theoretical calculation natural frequencies and the equivalent stiffness of FEM model are obtained by the vibration model of LRG. The first5-order FEM analysis natural frequencies are also obtained by the FEM modle of LRG in two different boundary conditions. Accuracy of the theoretical model and FEM is verified by the dynamic test of the LRG.