Affiliation:
1. School of Mechanical Engineering, Beijing Institute of Technology, Beijing, China
2. Hebei Huabei Diesel Engine Co., Ltd, Hebei, Shijiazhuang, China
Abstract
A failure analysis of starting motor is performed using analytical method and finite element method. The influence of external load and material properties on the stress characteristics were discussed. For 45 steel internal spline, the maximum contact stress is greater than the allowable contact stress. This may cause internal splines failure. The bending stress and shear stress are less than the corresponding allowable stress. To be specific, when the maximum 130 N/m applied to the spline coupling in finite element analysis, the contact stress, bending stress, and shear stress are 260, 144, and 40 MPa, respectively. The corresponding allowable contact stress, allowable bending stress, and allowable shear stress are 197, 400, and 200 MPa, respectively. The stress value at the addendum and side of internal spline is maximum, which has good consistency with the failure position of experimental test. In fact, the calculation results obtained from analytical study may have the possibility of underestimating or overestimating the true stress state. This is mainly because analytical study has certain limitations. Therefore, it is necessary to use finite element method to analyze the stress state of the spline structure under design loads and determine whether its strength meets the design requirements.