Research On The Ball-Screw's Influence Of The Nonlinear Vibration Of The Machine Tool Feeding System Table

NC machine tool industry is an important measure of national industrial manufacturing,and NC machine tools are widely used in almost all of the manufacturing industry,such as aerospace,shipbuilding,automobile,machine tool,light industry,general machinery,engineering machinery.For NC machine tool,the mechanical parts of feed system is the most core part,feed system is a tool or workpiece movement conversion and execution parts.NC machine tool performance relies heavily on the system dynamic performance.At present,the machine tool feed system toward large stroke,high load and high precision develop ing direction,how to increase stroke and load capacity and keep system response have high precision,high reliability,is a research direction of practical engineering and have application value.Ball screw and rotary motor mode of transmission structure features,especially the structural parameters of ball screw and dynamic performance determine the travel,load capacity and precision of the feed system.Ball screw structure is complex,its stiffness on the system show that the nonlinear,lead to nonlinear vibration characteristics of feed system response.Nonlinear systems are often accompanied by chaotic motions of the phenomenon,the emergence of chaos phenomenon leads to precision feed system dynamic response is difficult to improve,especially in the case of large stroke,high load,the nonlinear features more obvious.These nonlinear characteristics will lead to the numerical control machine tool positioning acc uracy of ball screw feed system,machining precision and machining,serious vibration will cause machine tool parts,reliability,lower intensity,damage,resulting in a machine tool service life and safety.At the same time,the vibration of the machine also can cause unnecessary energy dissipatio n,yield reduction processing,vibration produced by the noise and the phenomenon of instability will cause harm to machine tool operators.Paper machine ball screw feed system components to consider the quality of the centralized processing,considering the screw torsional deformation caused by the nonlinear elastic force,machine tool feed system mechanics model is set up.Ball screw feed system is based on the analysis of the equivalent stiffness and equivalent mass,considering the ball screw length,d iameter,lead,workbench position influence on the equivalent stiffness and equivalent mass,consider screw torsional deformation caused by the nonlinear elastic force the ball screw machine tool feed system of Duffing equation of dynamics equations used to describe the table.Q uantitative analysis,using the method of Lindstedt-Poincare equation approximate analytic solution is obtained by system,through the analysis of the approximate analytical solution of nonlinear systems in the solution,the amplitude frequency response characteristics,revealed the amplitude frequency characteristics of nonlinear vibration of the feed system and the screw parameters,the relationship between the excitation amplitude.Q ualitative analysis and MATLAB to system get the system phase diagram and the time domain waveform,ball screw feed system vibration model of the phase diagram and the time domain waveform display screw parameters and exciting force on the stability of the system,the singularity distribution,the influence of boundary limit cycles have certain rule,the time domain waveform and phase diagram reflects the system response for the quasi periodic motions and chaotic motions of the state.Study on screw parameters,workbench,position the influence law of motion of the system.Through the Poincare map,Lyapunov index and bifurcation diagram analysis screw parameters and excitation parameters on the system response is periodic,stability,the influence of the state of bifurcation and chaos.To build CNC machine ball screw feed system test bench,a vibration excitation test was done for ball screw feed system,vibration signal by dynamic signal analysis system on the vibration signal data post-processing,through continuous frequency spectrum and the ball screw modal test ball screw feed system dynamic characteristics of nonlinear vibration of judgment.The conclusion based on the theoretical analysis and experimental results,through the ball screw pair of NC machine tool feed system dynamic characteristics and the matching rule of ball screw parameters,the proposed machine tool feed system of nonlinear vibration active control and passive control methods,the nonlinear vibration of ball screw machine tool feed system provides some measures of vibration reduction.