Research On The Dynamic And Thermal Characteristics For The Spindle Assembly Of A High Precision NC Lathe

As the foundation of manufacturing industry,the improvement of design and manufacture level of the machine tool is one of the necessary and important links for our country from the manufacturing power to the manufacturing power;As an important product in the machine tool industry,the design and manufacture level of CNC machine tool has also restricted the development of manufacturing industry to the high,fine,sharp direction.As the key part of NC machine tool,the dynamic and thermal performance of the spindle components have great influence on the machining accuracy of the machine tool.However,the research on its single characteristics can't meet the improvement of the performance of machine tools.In this paper,a high precision CNC lathe spindle components for the research object,its dynamic and thermal characteristics are studied by simulation and analysis.The main research work of this paper is as follows:(1)On the basis of consulting the domestic and foreign literatures,master the research status of dynamic and thermal state and coupling characteristic analysis of high precision NC machine tool spindle system,clear the main content of the research topic as well as to solve the key technical problems,and determine the research ideas and methods.(2)Theoretical model for the oil film characteristics of hybrid bearing is built.The bearing capacity,stiffness,damping and other parameters of hybrid bearing are calculated by the method of difference and numerical calculation,and the relationship between these parameters and the performance of the main spindle system are analyzed.(3)Study on the finite element model of hybrid bearing oil film and its finite element analysis.Analyzed the distribution of the pressure field and temperature field of the oil film under different pressure and rotating speed by using the established model.By analyzing and calculating the oil film pressure and temperature field,the change tendency of the parameters such as deflection angle,bearing capacity and temperature change is obtained.(4)The finite element simulation analysis model of the spindle system is established.By means of one way fluid solid coupling method,the temperature rise and thermal deformation of the spindle unit under different rotating speed and oil film pressure were calculated,through the oil film pressure field and temperature field as the load.So the influence of the dynamic and thermal characteristics of the spindle components on the accuracy of the machine tool is analyzed.The thesis studied and verified the correctness of the hybrid bearing oil film pressure calculation model,and calculate the spindle components under dynamic static pressure bearing under the influence of the fluid solid coupling characteristic.Through the analysis of dynamic and thermal characteristics of CNC lathe spindle components,the characteristics of the main spindle system under various factors can be obtained,lay the foundation for further improving the design level of high precision machine tool spindle parts.