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

Spindle assembly is one of the key units for CNC machine tool.The static and dynamic property of spindle assembly has crucial influence on machining precision.Therefore,the research on the static and dynamic property and the influence of spindle performance is of great importance for CNC machine tool development.The thesis makes a research on the spindle assembly of CNC lathe of static,dynamic and thermal property.The main research work is as below.(1)On the basis of the research of the related literature at home and abroad,the author summarizes the research situation and the latest developments of the spindle assembly and the film of hydrodynamic and static bearing.The main research content and methods are determined.(2)The 3D model of hydrodynamic and static bearing and oil film is built.Numerical method is used to calculate the pressure field.The value of oil film pressure and regularities of distribution is found by programming solution.(3)The spindle static and dynamic property is built and analyzed.3D model of spindle is built by finite element analysis software.Spindle static,modal and harmonic is analyzed.The amplitude on different areas of the main shaft with the change of vibration frequency is presented.The critical speed of the spindle and the low order resonance frequency are determined.(4)The oil film pressure and temperature field distribution of the hydrodynamic and static bearing simulation analysis is finished.The hydrodynamic and static bearing oil film 3D model is built.The film pressure,temperature and the flow condition in oil intracavity are analyzed by the use of fluid analysis software.The pressure and temperature field distribution and flow condition in oil intracavity are obtained.(5)Parameterization machine tool spindle analysis system is developed based on VB 6.0 software.The VB is used to develop visual graphical user interface and database is built by SQL Server.Furthermore,using visual programming software to call finite element analysis software and read APDL document has been realized,which can improve the working efficiency of spindle system developersThe spindle static stiffness,dynamic stiffness and natural frequency values are obtained by the research of lathe spindle static and dynamic property.The correctness of the research methods of hydrodynamic and static bearing film theory is verified.The regulation of film pressure and temperature field distribution in different working conditions is obtained.Valuable reference data is provided for machine tool research and development personnel.