Analysis Of Thermal Characteristics Of Permanent Magnet Synchronous Spindle

With the rapid development of CNC machine tool technology,the technical requirements for permanent magnet synchronous electric spindles are getting higher and higher.Permanent magnet synchronous electric spindles have been accepted more and more because of their high power density and high efficiency.However,the thermal deformation caused by heat still restricts the precision of precision machine tools.Therefore,from the analysis of the heat generation and heat transfer rules and influencing factors of permanent magnet synchronous electric spindle,the thermal performance of the electric spindle system is studied by the combination of finite element software simulation and experiment.The specific work is as follows:The structural characteristics of permanent magnet synchronous electric spindle system,the heat transfer of electric spindle and the mechanism of heat dissipation are analyzed.The thermal characteristics of permanent magnet synchronous electric spindle are studied.The heat and heat transfer of electric spindle are analyzed.According to the modern heat transfer theory,the mathematical model and solution conditions of the permanent magnet synchronous electric spindle temperature field are determined.Using the finite element method to solve the thermal differential equation,and using the variational method to theoretically derive the temperature field of the electric spindle.The theoretical analysis of the built-in permanent magnet motor and bearing heat generation of the permanent magnet synchronous electric spindle is carried out to quantitatively calculate the heat generation of the inner bearing and the motor of the electric spindle.According to the heat transfer characteristics of the electric spindle,the thermal boundary conditions of the key components are analyzed,including the relationship bet-ween the heat transfer coefficient of the spiral pipe coolant and the flow rate,and the relationship between the heat transfer coefficient of other maj or thermal boundaries and the rotational speed.The finite element thermal analysis model of the permanent magnet synchronous electric spindle temperature field is established,and the finite element analysis of the temperature field is carried out to explore the temperature rise law of the key components of the electric spindle in the starting phase,stable operation phase and different speeds.According to the theory of heat conduction inversion,combined with conjugate gradient method and finite element thermal analysis model of electric spindle based on ANSYS software,and the heat source inversion model of permanent magnet synchronous electric spindle bearing is established.The finite element analysis of the temperature-structure coupling of the permanent magnet synchronous electric spindle is carried out to investigate the effects of thermal deformation and thermal stress generated by the internal thermal load of the electric spindle on the structure and deformation of the electric spindle.