Modelling and Analysis of Internal Excitation of Cracked Spur Gear Considering Effects of Tooth Errors

Time-varying mesh stiffness (TVMS) and gear transmission errors are the main internal excitations in the gear meshing process. How to establish an accurate calculation model of internal excitations has become an important step to evaluate the fault characteristics. The traditional internal excitation calculation model of cracked gear ignores the effects of tooth errors and tooth attachment position change caused by the crack, which will result in loss of computational accuracy in the body crack case and difficulty in characterizing the effect of tooth errors on the internal excitation of crack faults. To address this problem, a new analytical internal excitation calculation model of cracked gear considering tooth errors is developed based on the proposed variable-angle deformation energy integration (VADEI) method. Then the validity and accuracy of the proposed model are validated by the Finite element (FE) method, and the effects of the parameters of crack and different types of tooth errors (Tip relief error, tooth profile error and pitch error) on the TVMS, loaded static transmission error (LSTE) and load sharing factor (LSF) are investigated. The results demonstrate that the proposed model can satisfy the accurate internal excitation calculation for both the tooth and body cracked gears, and the tooth error has an important effect on the internal excitation aroused by the crack fault. This study can provide a theoretical reference for the establishment of crack fault diagnosis methods.