Dynamic Characteristics Of The Theoretical Modeling Of Spindle System Test Rig And Junction Research

Modern machine tools design requires them to have good performances such as high speed, high accuracy and low noise etc. so it' s necessary to research its dynamic characteristics of machine tools during a design. The spindle system of machine tool, as the structural complicated and low rigid component, its joint with the whole machine is the important factor in effecting the dynamic characteristics of the whole machine tool. In order to study the dynamic characteristics of spindle system and joints of spindle and whole machine, it' s significant in practice to establish general test-bed for spindle system dynamic characteristics analysis.In view of some shortcomings of the traditional methods, such as long production period, high cost and difficulty of design modification, ANYSYS 8. 0 software is adopted to establish the finite element model of test-bed and analyze its characteristics in the dissertation, based on the theory of CAD/CAE.Firstly, the 3D solid model of the analyzed object is built directly in the FEM software ANSYS 8.0 without using other CAD software. The influence of the side sizes of solid elements on computing results and the influence of coupling ways between different parts on the modal parameters are researched by simply modeling. And a new connecting method about joints in ANSYS is proposed and applied to finite element modeling of the test-bed for spindle system. Furthermore, several different computing techniques for modal parameters extraction are compared in solving the finite element model of spindle system test-bed. Many modal solutions are also done to achieve the relationships between the whole or part stiffness value and computed modal parameters. The laws about joint rigid parameters' influences on modal parameters are discussed by means of altering their values for conjoint parts. And by changing local rigid parameter values, the different location selections' influence on computed modal parameters is also studied.The theoretical model built in FEM should represent the real structure in dynamic performance. However the real conjoining condition of machine tools joint is so complex that it is very difficult to be embodied correctly in the finite element model. In this dissertation, several conjoining methods are tried out, but the modal solutions results have great difference, implying that an accurate theoretical model is attained only by modification according to model' s test data. Then right joint ways can be found. Additionally, the entire modal frequencies of the model grow, while the stiffness value of the spring-damp elements is increased. The modal modes also change, and some of them may be lost.In this dissertation, the elementary dynamical simulation in FEM for the spindle system of TH6350 bed machining center is performed and investigation in treating methods about joints in ANSYS are made, offering references for dynamical design and building theoretical model of joints based on ANSYS.