The Vibration Signal On-Line Analytical System Of Rolling Bearing

Vibration can reflect the dynamic behaviors of bearing, which has become one of the most important parameters to check bearing quality, and vibration measuring has been applied widely in bearing assembly line. However, the vibration measuring instruments in our country have many drawbacks such as complex structure, and simple function. In order to make up for these drawbacks, empirical workers often have to listen to bearing sounds. It is so ineffective and unreliable that domestic vibration measuring instruments hasn't met the mass production of bearing industry.In this paper, according to the design mode of virtual instrument, an on-line analytical system of bearing vibration signal is designed based on vibration fundamental and testing methods. The system consists of BVT-1A vibration measuring instrument, NIUSB-6009 DAQ card and computer. NIUSB-6009 DAQ card passes vibration signal from BVT-1A vibration measuring instrument into computer, and then the software structure of the system is designed by LabVIEW, signal acquisition and analysis are fulfilled by DAQmax and signal analysis sub-function in LabVIEW, if analysis result shows that bearing vibration is unqualified, the system will give an auto-alarm. the system can also carry out the function of playback, saving, printing and so on.In addition, some new methods about signal processing are used to improve detection accuracy. For example, in time domain, according to the shock pulse character of fault bearings and 3σprinciple in probability statistics, two new parameters, demodulation rms factor and pulse numbers are calculated to check whether bearing is unqualified If bearing is unqualified, in frequency domain, Savitzky-Golay filter is applied to improve the SNR, the ZOOM-FFT envelope analysis and cepstrum analysis based on energy operator demodulation, improved STFT are used for extracting bearing fault frequency, and finally the fault position can be found in contrast with theoretical frequency.In order to test the on-line detection system, the deep groove ball bearing in assembly line is taken as samples for experiment, the result shows that vibration quality of rolling elements can be judged quickly and exactly by the system, what is more, the system has such advantages as convenient maintenance, short development time and friendly interface and so on. The system not only extends the function of BVT-1A vibration measuring instrument, considering the flexible manufacturing, but also can test many kinds of bearing types to meet the work condition when software and hardware systems are designed.