Mechanical Characteristics Analysis And Experimental Research Of Machine Tool Spindle Bearing System

High-end CNC machine tools are the "industrial master machines" of the manufacturing industry and are widely used in the mass production of parts and components.The spindle of the machine tool rotates the workpiece or tool to transmit the speed and torque,thereby achieving the purpose of processing the workpiece.Angular contact ball bearings,as the main supporting components of the machine tool spindle,are used to ensure the working position and rotation accuracy of the machine tool spindle under different speeds and different load conditions.Therefore,the angular contact ball bearing supporting the main shaft of the machine tool is subjected to a coupling analysis of dynamics and thermal elastohydrodynamic lubrication,and the ball bearing stiffness and damping models under different speeds and different load conditions are established.The stability and reliability of the spindle operation and the improvement of the machining quality of the workpiece are of great significance.The main research contents of this article are as follows:(1)Analyze the structure of the machine tool spindle and angular contact ball bearings.Based on the ball bearing dynamics,analyze the movement relationship between the ball and the groove tracks of the inner and outer ring grooves,and then establish the internal contact force between the various components of the ball bearing structure.Equations of equilibrium and equations of motion.Through the finite element simulation of the ball bearing under different external loads,the stress and strain in the contact area of the ball bearing were obtained.(2)The solution principle and steps of the multi-grid method are explained,and it is applied to solving the problem of elastohydrodynamic lubrication.Aiming at the complicated working conditions of high speed and high temperature of the machine tool spindle,the influencing factors of thermal effects are introduced,and the thermo-elastohydrodynamic lubrication equation is established to solve the oil film thickness and oil film pressure of the lubricating oil film,and the changes of the oil film thickness and oil film pressure under different speeds and loads The trend provides theoretical support for the coupling of bearing dynamics and thermoelasticlubrication.(3)Aiming at the interaction and interaction between the mechanical parameters of the ball bearing contact area and the thermoelastohydrodynamic lubrication parameters,this paper combines the theory of dynamics and thermoelastohydrodynamic lubrication,and uses the finite element software to solve the fluid-solid coupling of the ball bearing.The stiffness and damping of the ball bearing under the action of the lubricating oil film are further calculated.At the same time,the transient dynamics of the machine tool spindle amplitude is studied based on this,and the machine tool spindle amplitude under different speeds and different loads are solved.By analyzing the variation of the machine tool spindle amplitude under different speeds and different loads,the change relationship between the machine tool spindle amplitude,stiffness,and damping is determined to provide a theoretical basis for ensuring the stable operation of the machine tool spindle.(4)Establish a machine tool spindle bearing system experimental bench to identify the parameters of the ball bearing stiffness and damping under thermalelastohydrodynamic lubrication.Measured the spindle's amplitude under different speeds and different loads,and compared and analyzed the theoretical,simulated and experimental values to verify the accuracy of the machine tool's spindle amplitude model under the coupled analysis of dynamics and thermoelastic lubrication.Theoretical basis.