Study On The Vibration Characteristic And Typical Fault Diagnosis Of Mine Hoist System

The mine hoist system is the large-scale and complex machine, with the duty of hoisting the coal and gangue, lowering material and lifting personnel and equipments. So it is called"the laryngopharynx of mine production". Once some of the equipments breaks down, it is extremely disadvantageous to the coal mine production and the personal security. Since the hoist system works under varying speed and load, the present study about vibration mechanism of hoist system under varying work condition is little, say nothing of research about non-stationary vibration signal processing method. Simultaneously, there is a lack of vibration evaluation standard corresponding to the large-scale equipment in hoist system under varying work condition. Consequently, in view of vibration characteristic analysis of hoist system, fault mechanism and typical fault diagnosis method of hoist system under varying work condition is studied systematically, ensuring the safe and reliable operation of hoist system.Horizontal and vertical vibration models of the hoisting container under the steel guide were established firstly in this dissertation, and the following experiment verified this model accurate. Based on the model and experiment, the vibration characteristic of hoisting container under different faults of steel guide was studied systematically, which laid a foundation for the determination of detection and signal processing method of mine steel guide failure diagnosis. Then, the methods of vibration signal processing of the hoisting container and the failure feature extraction of steel guide were discussed in detail. Since the hoisting container vibration could not reflect deflection of steel guide, it was proposed the detection method by tilt sensor sensing the deflection of steel guide directly. And then wavelet multi-resolution analysis was used to process the tilt signal to extract the tendency of steel guide. Consequently, the effective recognition of failure, failure location as well as failure severity appraisal became possible.Based on the establishment of vibration mathematical model of hoist gearbox, signal characteristic of hoist gearbox under varying speed and load was analyzed, at the same time, the influence of hoisting container on gearbox through hoist wire was also analyzed. And then, effective signal processing method of hoist gearbox under varying work condition was proposed. Because the EMD method could recognize different condition of gearbox from signal energy distribution of single component decomposed from hoist gearbox acceleration signal with the auto-adapted decomposition ability, diagnosis method based on the EMD energy entropy was carried on. Meanwhile, because of the superiority of order analysis in analyzing vibration signal related to rotational frequency or shaft speed, and the key The key to the order analysis is the constant angle sampling of vibration signals, so the calculated order tracking suit for the coal mine field was proposed in the foundation of predecessor's work, and the hoist gearbox failure diagnosis was realized. Along with development of modern technology, instantaneous frequency obtained from the original vibration signals and the order tracking become the emphasis of order analysis. In view of the detailed research of order tracking based on instantaneous frequency estimation, a new instantaneous frequency estimation method combining time-frequency ridge and time-frequency reassignment based on empirical mode decomposition was put forward, which ultimately realized the instantaneous frequency extraction of vibration signal during hoist gearbox run-ups and the angle re-sample of original signal.