Experiment And Singal Analysis On Vibration And Noise Of DK4020 Ball Screw

The research object of this paper is DKFZD4020 ball screw provided by Nanjing Technical Equipment Manufacture Company.Theoretical modeling and analysis of ball movement,Optimization of return tube,dynamic simulation,multi factor orthogonal test,signal processing and several means are taken to analyze the influence factor of ball screw on vibration and acoustic.There are many similarities in mechanism of ball screw and rolling bearing,and they are known as the same "rolling element",so during the analysis of ball screw,signal processing method of ball screw is simulated by research on the vibration signal of bearing.The main research contents and contributions are summarized as follows:Firstly,the coordinate system of ball screw pair is established,based on kinematics theory,the kinematic relation between balls and nut is analyzed.Base on the Hertz contact theory and Newton's law,the impact model of the ball and the return tube has been deduced.The multi-body dynamic model of ball screw was built by dynamics simulation software ADAMS,the variation of the motion of the ball in the return tube and the causes of noise are analyzed by dynamic simulation.According to the motion model of the ball chain in the return channel.The goal of the optimization is the transmission eficiency of the ball chain and the force of the ball impact counter.The optimized objects are the radius of the track curve of the return device and the diameter of the cross section of the return raceway.The nonlinear optimization under the constraint condition is carried out by using Matlab.The dynamic simulation of the optimized ball screw model is been carried out,the collision force between the ball and the return tube is extracted and compared with the former.In order to verify the effect of the optimized return device and explore the influencing factors of the vibration and noise of the DK4020 ball screw,the orthogonal test of four factors and two levels was designed by taking the radius of the return device,the number of the bearing rings of the nut raceway,the diameter of the cross section of the return raceway and the waviness of the screw shaft as the experimental factors.The equipment and test procedures of the noise and vibration of ball screw are introduced.SPSS software is used to analyze the variance of the orthogonal test data,which confirmed the most significant factor to the vibration and noise of ball screw pair.Diagnosis methods of bearing fault signal are used for references.The principle and algorithm of wavelet packet and empirical mode decomposition(Empirical Mode Decomposition)are described succinctly in this chapter.Matlab is applied to the corresponding analysis of vibration and noise signal data collected by Labview.Process the vibration signal by using Fourier transform and Hilbert envelope,study on noise signal based on the combination of wavelet packet method and EMD,verify the correctness of the theory of ball pass frequency and excitation frequency of the waviness to the screw shaft.According to the results of orthogonal test,the relationship between the vibration and noise of the ball screw is analyzed,and the main noise mechanism of DK4020 ball screw is determined.