Thermal Deformation Analysis And Structural Optimization Of Motorized Spindle

In recent decades,electric spindle technology is widely used in high speed machine tool products, which is a new type of spindle system that Combines ac high-frequency motor and spindle. The motorized spindle developed by us with new materials sticks out in the spindle market, by virtue of its small moment of inertia, high resistance to wear, long life and other advantages. A lot of heat is produced both in built-in motorized spindle motor and high speed bearing Once the thermal dissipation is not good, the heat will be deposited on the inside of the motorized spindle, which may lead to spindle axial thermal expansion, the failure of bearing inner lubricant, the increase of internal thermal stress and the spindle thermal deformation. Therefore, study on thermal deformation and thermal stress of the spindle unit, thereby providing rationale for thermal compensation of machine tool, has become the key to achieving high speed cutting.This paper conducts a in-depth study on thermal stress and thermal deformation of the spindle when it reaches a steady-state temperature field, its target is to improve thermal performance and reduce the spindle thermal deformation of machining.It analyzes the heat source of spindle based on the predecessor's theory of thermal properties, finally uses finite element analysis program by summarizing the method of analysis. It builds 150MD24Z7.5 and 150MD24Y20 electric spindle three-dimensional finite element analysis of model, then use ANSYS software to analyzes spindle thermal finite element. It analyzes the temperature variation with time and temperature distribution of spindle unit hot-point.The calorific value of rotor and bearing is calculate accurately by use of basic data measured in loss experiment under different rotational speed. Then electricity spindle temperature field is analyzed. The spindle temperature rise test is built through power testing system, then comparative analysis of motorized spindle temperature rise by ANSYS and verify the correctness of theoretical models.It analyzes and discusses electric spindle thermal deformation and thermal stress which is generated at different speeds, which bases on the analysis of spindle steady-state temperature field. Then it studies that thermal stresses and thermal deformation have effects on the structure of electric spindle and proposes measures for improving the thermal distortion of electro-spindle. The spindle thermal displacement experiment is established through displacement sensor to verify the validity of finite element model and theoretical analysis.It will put forward the optimization scheme based on theoretical analysis. The distance between stator and rotor's has influence on thermal characteristics and the flow rate of the lubricating oil has an effect on spindle thermal characteristics. Using finite element analysis software ANSYS to spindle simplified model for finite element simulation of thermal distribution, thermal gradients, thermal deformation. Then the spindle thermal distribution, heat transfer law, heat deformation are worked out. The analysis of the results can improve the optimization purposefully in the design and production of high speed electric spindle, reduce blindness, provide supported mechanism design theory for the successful development of high speed electric spindle. This paper analyzes not only the thermal deformation law of the spindle, but also the distribution of temperature, thermal deformation, thermal stress as well as the corresponding structure optimization, which provides theoretical basis for developing electric spindle with high precision, high speed, high power, high torque, high reliability.