Research On Heat Dissipation Law Of High Speed Permanent Magnet Synchronous Motorized Spindle And Optimization Of Cooling Structure

High-speed permanent magnet synchronous motorized spindles have obvious high power density compact structure,high efficiency and stable output torque characteristics.In recent years,they have been more widely used in the field of high-speed machine tools.However,since the high-speed machining technology requires higher speeds and power den sities of permanent magnet synchronous motorized spindles,the heat dissipation of the fixed rotor is increasingly restricted by small structural size.It is difficult to achieve effectively heat dissipation in a limited space for the fixed rotor and beari ngs.On the one hand,the temperature increment cause thermal extension and deformation on spindle,which might reduced the machining accuracy.On the other hand,it might cause irreversible demagnetization of the permanent magnets.Therefore,a high effective dissipating stator and rotor structure of high-speed permanent magnet synchronous electric spindles is to be developed urgently.(1)A 6k W/60kr/min spindle prototype is designed,and steady-state temperature field model of the spindle is established.According to the principles of heat transfer and computational fluid mechanics,the heat transfer process at the fluid-solid coupling surface is fully studied,and the analysis and calculation model of the steady-state temperature field of the motorized spindle is established.CFD and FEA fluid-solid thermal coupling simulation is conducted to calculate the spindle temperature field and steady-state temperature field accurate numerical simulation of the spindle is realized.(2)The influence of stator cooling structure and cooling medium parameters on spindle temperature is studied.The influence of stator cooling jacket structure,material,inlet oil pressure,inlet temperature and ambient temperature on stator temperature is revealed.The stator heat dissipation can be effectively improved by refining the cooling structure and cooling system parameters.(3)The influence of cooling structure,cooling medium parameters on rotor temperature is studied.The rotor temperature can be effectively controlled by rotor center cooling method.The rotor heat dissipation and structure strength could be balanced by refining cooling tunnel diameter and cooling medium parameters.(4)A high-speed spindle temperature test rig is constructed.The theoretical and experimental data is compared to verify one-way fluid-solid thermal coupling method accuracy and the cooling optimization scheme effectiveness.The research sho ws that the component temperature relative error s between the theoretical data and the experimental data are within 15%,which meets the general engineering requirement.This research realized accurate temperature field simulation of a motorized spindle.It is valuable for high-speed motorized spindle design,temperature filed analysis and cooling structure optimization.