Mechanical Characteristics Analysis Of Double Support Motorized Spindle Bearing

With the continuous improvement of manufacturing accuracy and efficiency requirements,the products produced by traditional machine tools are far from meeting the needs of the public.The position of NC machine tool is higher and higher,and the core of NC machine tool is motorized spindle.In order to improve machining accuracy,high-speed motorized spindle came into being.For high-speed motorized spindle,the type of bearing selected is the top priority.In order to improve the rotating speed and maintain stable operation,the subject of double support spindle system of magnetic bearing and ball bearing is proposed.In the double support,the preload of the ball bearing is appropriately reduced,the limit speed of the ball bearing in the double support is increased,and the magnetic bearing is used to assist the support to improve the stiffness of the double support.Thus it is reflected that the bearings advantages of double support moterized spindle.This subject adopts diagonal contact ball bearing and magnetic bearing double support,so it is necessary to model the magnetic bearing and analyze the mechanical properties of the magnetic bearing with Maxwell.To analyze the structure of the ball bearing,we must first establish its static model,which is used to provide the initial value for the dynamic model of the ball bearing.Using MATLAB to compile the dynamic model of angular contact ball bearing,analyze its mechanical characteristics,and get the change trend of angular contact ball bearing stiffness under various working conditions.In order to improve the support stiffness,the dynamic characteristics of two different arrangement modes and the dynamic stiffness of angular contact ball bearing under the same working condition are analyzed by using the quasi-static method and the change trend of stiffness is obtained.Finally,the diagonal contact ball bearing with back-to-back arrangement is adopted.The maximum electromagnetic force of the magnetic bearing and the supporting stiffness of the paired ball bearing are obtained through simulation,and the stiffness value of the ball bearing is substituted into the rotor model of the double support motorized spindle.Using the finite element method and the transfer matrix method,ANSYS and MATLAB are used to analyze the double support transit subsystem and then find the critical rotation speed.