Bearing Fault Diagnosis System Of Research And Development

Rolling element bearing is one of the most easily damaged parts of electromechanical systems. A lot of mechanical failures are relevant to the state of rolling element bearings. It is estimated that about 30 percent of mechanical failures is caused by the faults in the rotating machine with rolling element bearings. It is obvious that the quality of rolling element bearings has a great impact on the working conditions of electromechanical systems. Because of poor design, poor working condition or a jump heavy load, bearings will be damaged and worse during the running time. The fault diagnosis of rolling element bearings is a research highlight.Based on widely reading of references and understanding of bearing vibration test technology and bearing fault analysis theory, the analysis methods of vibration signals are discussed thoroughly, including time domain analysis, frequency domain analysis and time-frequency analysis, as well as general approaches of extracting features from the time domain and frequency domain are introduced. The envelope analysis method based on Hilbert's transform is deeply investigated. This method can diagnosis the faults of rolling element bearings with high precision.In this paper, the types of faults and the charactieristic frequency of fault are investigated.The diagnosis system for rolling element bearings based on Hilbert's transform is developed. The theory of Hilbert's transform and its application in envelope analysis are introduced in this paper. The USB 9233 type data acquiring card is used in the diagnosis system, and this type of DAQ card is designed for vibration and noise measurement by National Instruments. The developing process of the diagnosis system including: vibration signal acquisition, signal process and faults diagnosis. The diagnosis system is developed based on LabVIEW.In order to vilidate the diagnosis system developed in this paper, an experimental study is carried out.The rolling element bearing of type 6203 is analyzed in the experimental study. The bearing vibration signal is collected by system firstly, and it is analyzed by the software. The fault in outer race is diagnosed. The further experimental results vilidate the analyzing results. The experiments results show that the diagnosis system can identify the bearing faults accurately.Finally, the research work and the contributions of the dissertation are summarized, and some problems which need to be studied further are also pointed out.