Machine Tool Motorized Spindle Preload And Clamping Force On The Influence Law Of Dynamic And Static Characteristics

With the development of modern manufacturing,high speed CNC machine tools have become an important development direction of machine tools.The design and manufacture of high speed CNC machine tools become the core technology in the core component of high-speed CNC machine tools.The structural design,the static and dynamic performance of the high speed motorized spindle could determine the machining ability.Therefore,an in-depth study for high speed motorized spindle has very important significance to improve the performance of high speed CNC machine tools.1.In this paper,based on frame structure of Weiss 175982 motor spindle,two typical frame structures of high speed motor spindle are analyzed.Then,the typical failure mode and failure cause of main functional units are analyzed and researched,as well as their influence on motor spindle.2.Based on analysis on frame structure of high speed motor spindle,the effect of bearing axial preload on working performance and bearing life of the motor spindle is researched.According to theoretical analysis and experimental research of Weiss motor spindle,with the increase of bearing axial preload,anti-bending stiffness of the motor spindle grows significantly,and the rated bearing service life reduces obviously.On this basis,preload selection standard that determines preload limiting value,bearing life and optimized stiffness rated value of motor spindle based on its rotation precision and bearing operating temperature is proposed.3.Static property of the motor is further researched,the influence of spindle properties is analyzed one by one.Then the conclusion that change of fore bearing preload can improve its static property and reduce radial offset is obtained.Besides,optimized analysis on broach force value of the motor spindle is conducted from two aspects of reliable clamping and convenient tool changing.4.Numerical modeling and simulated analysis of high speed motor spindle are done via ANSYS software to analyze the influence of bearing preload on it,and conclude that the inherent frequency of motor spindle increases as the bearing stiffness enhances.Its dynamic property is evaluated and the failure mode is predicted by means of its vibration data and bearing accelerated speed envelope value measurement.Finally the method that improves dynamic property of the motor spindle through bearing preload and rotor dynamic balancing is proposed.