Analysis Of Thermal Coupling Dynamics Of High Speed Motorized Spindles

At the high-speed operation,the dynamic characteristics of the spindle of the machine tool become the main factors that determine the processing quality and processing accuracy.The thermal stability of the spindle at high speed will seriously affect the dynamic characteristics of the spindle,and it is also a key factor limiting the further promotion of the high-speed spindle.Therefore,it is important to establish a regular model for the stability of the motor spindle at different temperatures and to analyze the thermal-structural coupling of the spindle unit.The study is based on the high speed milling machine electric spindle as the research object,and aiming at realizing high speed and high precision of motorized spindle,In order to get the temperature distribution cloud diagram of the electric spindle at different rotation speeds,a combination of theoretical calculations and numerical simulations was used to calculate the heat generation and heat transfer mechanisms of the electric spindle,and a thermal steady state analysis was performed on the electric spindle model.The obtained steady-state analysis results are applied as a load to the analysis model of the ANSYS structural field together with the load of cutting force in the structure field,thereby calculating the thermal displacement of the thermal-structure field analysis of the electric spindle model.The resulting thermal displacement results are used to modify the initial conditions in the ANSYS numerical simulation model.Through the relationship between the deformation and the load of the bearing,the variation of the stiffness of the bearing under thermal effects under different rotational speedsis obtained.The ADAMS model of the motorized spindle was established and the kinematics simulation was completed.The differences in the dynamic characteristics of the vibration-insensitive and the actual temperature-rising,as well as their causes,were compared and verified.Finally,by changing the spindle speed and using the stiffness variation law obtained at different speeds,the influence of thermal effects on the dynamic characteristics of the motor spindle under different operating conditions wasobtained.This verified the rationality of the structural design of the electric spindle studied in this study to reach a certain target,and also provided the reference data for the electric spindle to further increase the rotational speed,optimize the structural design and dynamic characteristics,and improve the machining performance of the machine tool.