Coupled Fluid-Solid Analysis And Experimental Study On The Dynamic Characteristic Performance Of Aerostatic Motorized Spindle

Aerostatic bearing supported spindle is one of a critical unit of the High Speed Ultra Precise NC machine. Its dynamic performance determines machining qualities and cutting capabilities, and is the important factors influencing the precision of the High-speed NC machine tool. So the study of dynamic performance for High-speed Motorized Spindle makes important and realistic sense.Currently, in the dynamic analysis of motorized spindle , the simplification way is often used to dealing problem of bear element stiffness, that is exchanging the baer unit with spring unit and then calculating the natural frequency and the vibration type of the spindle by digital arithmetic, like FEM and transfer matrix method。Moreover, it is suitable for dynamic analysis of spindle supported by non-sliding bearing。But it is oversimple to for the nonlinear problem of the aerostatic motorized spindle。In this system, which includes motor,bear and spindle, it is coupled with magnetism-Fluid-solid and its dynamic characteristic is non-linear. So in order to fine the relative way to anslyze this dynamic characteristic, this paper takes works to solve the dynamic problem of The High Speed Ultra Precise Aerostatic Motorized Spindle, such as FEM simulation analysis,experiment research,Structural optimization, which can be seen as follow:1,Base Navier-Stokes equation, the hydrodynamic action of the aerostatic bear is anslyzed. That is investigating the nonlinear performance of film dynamic anti-force and relative stiffness in different spindle speed and force, which is integrated by film pressure。By this means, it is precise to cut down tolerance from the tradition way to exchange the bear with spring unit.2,As to the Dynamic Response of magnetism torque and relative physical quantity in the working spindle, according to the mathematical model of whirlpool field, we anslyze the magnetic field and current density of motor by FEM software ANSYS。Then, basing this analyse, the magnetism torque is anslyzed as to magnetism-solid coupled system and mechanical features, and relative simulation is done by MATLAB. 3,The magnetism-Fluid-solid coupled FEM dynamical equation is established baed the previous analyse of aerostatic bear stiffness and motor magnetism torque so that it ground the relative simulation analysis with theory.4,According to the coupled dynamical equation, this paper use the module ,which is developed by theAPDL of ANSYS, to carry out relatve FEM dynamic simulation analysis of aerostatic motorized spindle.5,In order to prove the effective of the magnetism-Fluid-solid coupled FEM dynamic simulation analysis of Aerostatic Motorized Spindle, this paper launchs some experimental study, including static stiffness test,mode experiment and characteristic analysis in dry running. And the test data and the result of simulation analysis come to pretty uniform, which certifies the veracity of theory study.6,For the purpose of raising the spindle stiffness effectively, this paper use the FEM first order method to optimize the aerostatic radial bear. In this process,the hole-throttle number,distribution of hole-throttle,the modes of hole-throttle brought into optimization.