Research On The Fault Diagnosis Of The Helical Gear Transmission System

This paper studies the transmission system of helical gear reducer. Through theanalysis of time-varying mesh stiffness, we carry out research on the dynamics simulationsand fault diagnosis for normal gear and the one with tooth root crack. The main works areas follow:(1) Using the software UG, we build the three dimensional parametric model of thehelical gear transmission system and assembly it, which is then imported into ADAMSthrough software interface. We build the virtual-machine model of the transmission system,do many-body dynamics simulation and study the dynamical properties, which verify themodel and become the basis for next-stage researches.(2) Using ABAQUS, we build the finite element models for helical gear pair healthyand with tooth crack. By finite element analysis and stiffness calculation, we get theirtime-varying mesh stiffness curves and study the effects of crack on the contact forcedistribution, deformation and mesh stiffness of gear tooth.(3) We build the dynamics model of two degrees of freedom for the helical gear pairunder normal and tooth root crack circumstances. and get the kinematic equations, whichare solved numerically by MATLAB. Based on this, we get the dynamic characteristiccurves for gear system and analyze the effects of tooth crack on the dynamical propertiesof gear.(4) We study the signals of the crack fault dynamical simulation using waveletanalysis and frequency spectrum analysis method. Then we get the period properties andfrequency domain properties of crack fault, which verifies the feasibility of gear crack faultdiagnosis using wavelet analysis.(5) By designing the test plant to verify the correctness of the fault of tooth root cracksimulation method and diagnostic method in this paper. Through the linear cutting methodto produce the same as the numerical simulation gear model size and location of thesimulated tooth root crack on helical gear tooth root. we do the box vibration signalacquisition of reducer’s helical gear transmission under normal and tooth root crackcircumstances using accelerometers. By using wavelet analysis and spectrum analysismethod carry out time domain and frequency domain analysis of vibration signalrespectively, we conduct the experimental research on the diagnosis of crack fault. Results show that the experimental results are consistent with the theoretical analysis and thenumerical simulation results, which verifies the validity of the numerical simulationmethod of the root crack fault used in this paper and the wavelet analysis method isfeasibility and effectiveness of gear crack fault, but also provides research basis for gearcrack fault diagnosis method.