Design And Thermal Elongation Study Of High Speed Motorized Spindle With Carbon Fiber Structure

High-speed motorized spindle as the core component of nc machine tools or machining centers,when it works at high speed,the internal friction bearing and motor stator rotor electromagnetic loss will produce a lot of calories,makes the motorized spindle temperature rise,making the motorized spindle thermal deformation,thermal elongation quantity is big,reduce the motorized spindle machining accuracy,In serious cases,it will even destroy the normal structure of the motorized spindle,so that it can not work properly.Therefore,it is necessary to study the heat generation and heat transfer process in high-speed motorized spindle and take various measures to reduce the temperature of motorized spindle.Carbon fiber has the characteristic of anisotropy.Although carbon fiber has a large thermal conductivity along the fiber direction,carbon fiber material has a small thermal conductivity along the direction perpendicular to the fiber direction.Therefore,this paper explores the setting of a carbon fiber sleeve between the spindle and the front bearing to reduce the heat transfer to the spindle generated by bearing friction,thus reducing the temperature of the spindle,reducing the axial thermal elongation of the spindle,and improving the machining accuracy of the motorized spindle.First of all,through the analysis of the development plan of the motorized spindle,and the market research to determine the technical indicators of the motorized spindle,and then the overall layout of the motorized spindle,motor,bearing,spindle,carbon fiber shaft sleeve,cooling and sealing system,tool change system design and relevant check.Finally use SOLIDWORKS software to establish a three-dimensional model of high-speed motorized spindle containing carbon fiber structure.Secondly,the three-dimensional model of high-speed motorized spindle with carbon fiber structure is simplified,and on this basis,the force and constraints of motorized spindle are studied.Then,the statics simulation is carried out by ANSYS Workbench software to obtain the distribution law of stress and strain to ensure the rationality of motorized spindle structure.Modal analysis was carried out to study the possibility of resonance.The influence of cutting force on motorized spindle was discussed by harmonic response analysis.Thirdly,according to the relevant principles of heat transfer,this paper analyzes the electric motor electromagnetic loss and the heat generated by bearing friction of the high speed motorized spindle with carbon fiber structure,and studies the cooling strategy.By simplifying the 3D model of high-speed motorized spindle with carbon fiber structure,and using ANSYS Workbench software to establish thermal-solid coupling model,the steady-state heat and thermal elongation of motorized spindle were simulated and analyzed,and the steady-state temperature field cloud and steady-state thermal elongation quantity cloud of motorized spindle were obtained.The effect of carbon fiber bush on temperature and axial thermal elongation of electric spindle was studied.Finally,an experimental platform was built to measure the thermal elongation of the motorized spindle with and without carbon fiber sleeve,and the experimental data were processed and analyzed to explore the influence of carbon fiber sleeve on the thermal elongation of the motorized spindle.The temperature measurement experiment of high-speed motorized spindle containing carbon fiber sleeve was carried out at different speeds,and then the experimental results were analyzed to determine the temperature distribution law,which was mutually verified with the thermal elongation measurement experiment.It was determined that the carbon fiber sleeve had the effect of reducing the temperature of spindle and the thermal elongation of nose in the motorized spindle.