Research On Ultrasonic Vibration Antifriction Of Ball Screw Pair

With the development of the modern manufacturing industry,the positioning accuracy of Computer Numerical Control(CNC)machine tools has attracted more and more attention from the public.The ball screw pair is the key subsystem of CNC machine tools and its friction state determines largely the function of CNC machine tools.In this thesis,a certain type of ball screw pair is taken as the research object and a method of reducing the friction of the ball screw pair by using ultrasonic vibration is proposed.And the ultrasonic vibration antifriction of the ball screw pair is explored by theory and experiment.In the section of theory,the kinematics of the ball screw pair is analyzed by using Hertz contact theory and coordinate transformation theory.The contact model of the ball screw pair is established and the friction between the ball and the raceway is determined.The structure of the antifriction vibrator and the composition of the ultrasonic vibration antifriction system of the ball screw pair are determined.Combined with the basic principle of ultrasonic antifriction,the principle of ultrasonic antifriction of ball screw pair is analyzed.The structure of the antifriction vibrator is determined and the finite element model of the antifriction vibrator is established.It is determined that the antifriction vibrator adopts the second order torsional vibration mode to reduce friction.In the section of experiment,the piezoelectric vibrator and assembles the antifriction vibrator are processed.The vibration mode and resonance frequency of the antifriction vibrator are tested.The ultrasonic vibration antifriction system of the ball screw pair is built and the antifriction effect of the antifriction system is tested.The results prove that the antifriction vibrator can significantly reduce the friction of the ball screw pair.