Study On The Wear Evolution Of Wire Electrical Discharge Machining Guid Pulley Bering

Rolling bearing is widely used in all kinds of rotating equipment as the key component.Especially in CNC machine and industrial robot and other areas call for high accuracy of motion.The bearing's operating condition directly affects the accuracy and reliability of the whole mechanical equipment.Wear is a common failure forms for rolling bearings.It will cause the bearing clearance increases and the surface roughness increases and reducing the running accuracy of bearing.For the bearings used in Precision machinery,the failure form that limited the bearing life is wear.The vibration signal of guid pulley bearing used in WEDM is the research object and the bearing fault feature extraction and wear evolution are studied.Three signal processing methods are used to extraction the rolling bearing fault related characteristic parameters.They are time domain statistical analysis and amplitude spectrum analysis and wavelet packet decomposition.But there is redundant and irrelevant components of statistical parameters due to a variety of statistical parameters used to reflects the bearing operation state.Then different parameters are changed in different period of bearing.So the sensitivity of each parameter is analyzed by calculating the derivative.The human auditory system is sensitive to the sudden change of sound.Because Gammatone filter bank has a good frequency selective and analysis characteristic.It is used to extract the frequency components that contained bearing fault information.And then conduct Hilbert transport to the signal and analyze the envelope result to summarize the fault frequency.Analysis of the changing trend of the frequency components with the bearing wear.Use extreme points and probability density method to judge if there is impact in filter channel and extract the instantaneous impact component of the vibration signal and its distribution in time domain.Based on the frequency and time domain analysis of the shock signal,the state evolution of the bearing is analyzed.The ability of the human auditory system has a very strong signal analysis and identification.The auditory nerve lateral inhibition is simulated to enhance resonance peaks in the vibration signal,highlight the changes in frequency and suppress the noise.The spectrum that calculated from the bearing vibration signal can express auditory signal time-varying characteristics especially It has obvious advantages in the characterization of instantaneous of signal waveform and has very good effect for the description of the weak signal in high-frequency range.