Research On The Reliability Evaluation Of Gears Based On The Vibration Signals

Gear transmission is a major way of mechanical transmission, as the inevitable phenomenon and the final destination of gear transmission, gear failure is one of the important reasons which induced malfunction. Gear reliability evaluation is significant for preventing sudden accident, reducing the maintenance cost and improving economic performance. Gear meshing vibration signals can effectively reflect the dynamic characteristics and working accuracy in the equipment operation and reveal the degradation rule of the equipment performance. The gear reliability evaluation method based on the gear meshing vibration signals is proposed in this paper.1. According to the reliability analysis method, the Weibull proportional hazards model is built to establish a link between characteristics of the indicators which reflect the equipment running status and reliability indexes, the gear reliability evaluation method and flow chart is put forward based on the model.2. The method for feature extraction of the gear faults is proposed based on wavelet packet analysis and distance evaluation technology. The sensitivity of characteristic parameters for the faults is great significance for the accuracy of gear reliability analysis. First of all, according to the gear vibration signal analysis, using time domain synchronous average for denoising processing of the target gear vibration signals, then extracting the distance evaluation factor as the feature vector for the frequency band energy by application of wavelet packet analysis, and optimizing the larger one as the response covariate in the model.3. Estimating for the parameters of the fault function based on maximum likelihood estimation. The Nelder-Mead’s iterative optimization algorithm is used for setting the initial value of optimization estimation, optimizing the function by application of fminsearch in Matlab optimization toolbox, it can effectively obtain the estimated parameter for the function of gear proportional hazards and realize the gearbox reliability evaluation.4. Building a test bench for gearbox faults diagnosis to experiment on gearbox for the whole life cycle. Gear vibration acquisition system is developed for signal acquisition, data preprocessing and reliability analysis, this method is successfully used on the identification of three stages in the whole lifecycle, verifying the effectivenesson gearbox reliability evaluation and performance degradation state recognition.