Research On Effect Of Bearing Preload On Dynamic Performance Of Feed Drive System And Development Of Test System

Feed drive system is a key part of CNC machine tool.The assembling quality and preload have a great effect on dynamic performance of feed drive system,especially on machining accuracy and stability of CNC machine tool.Research on the influence law of preload on dynamic performance of feed drive system,which can provide guidance for assembly and adjustment of feed drive system,has an important value for engineering application.Ball-screw feed drive system of CNC machine tool is studied in this dissertation.The method for measuring preload and the influence law of preload on kinematics and thermal performance of feed drive system are investigated.The performance test system of feed drive system is developed.The research results provide theoretical and technical foundation for reasonable selection of drive units preload and performance tests of feed drive system.The main works are as follows:The stiffness of support bearing at different preload is calculated based on Hertz contact theory.Combined with the test platform of feed drive system,the calculation result of bearing stiffness is verified with the comparisons of the results between finite element analysis and experimental modal analysis.On this basis,the influence law of bearing preload on vibration characteristics of feed drive system is investigated.The scheme of bearing preload measurement is determined and the calibration device is designed.The hardware and software modules of performance test system of feed drive system are developed.The performance test system is focus on bearing preload measurement and experimental tests on kinematics and thermal performance at different bearing preload.Based on the above-mentioned work,bearing preload measurement and experimental tests on kinematics and thermal performance at different bearing preload are performed on the test platform of Z-direction ball-screw feed drive system.According to the test results,the influencing tendencies of bearing preload on kinematics and thermal performance of feed drive system are investigated.The research results provide theoretical and technical foundation for assembly and adjustment of drive units of feed drive system.