Spiral Bevel Gear Fixed Frequency Calculation And Contact Analysis

Being a basic transmission part in aero engine, spiral bevel gear, which has such features as powerful transfer torsional moment, accuracy of transmit motion and high reliability, that can be used for the transmitting power and the motion between intersectant axes. To ensure its safety in working the dynamic features of the gear drives should be further studied. And its vibration and stress in condition of the loads should be analyzed in order to design high-performance spiral bevel gears.Spiral bevel gear is always working in condition of meshing with centrifugal stress, which caused by rotary speed and mesh strength, which caused by meshing, so its dynamic frequency in this condition is different from its intrinsic frequency. Based on the characteristic of cyclic symmetric structure, the finite element model of a single tooth of spiral bevel gear was set up. By the effort of copying element, a whole model of spiral bevel gear included hub and spokes board was created. Through data transforming, then put it into ANSYS. A modal analysis of spiral bevel gear under prestress caused by rotary speed and meshing torque was carried out by ANSYS. Dynamic frequencies of spiral bevel gears, which had different geometrical models were calculated. The result shows that rotary speed and meshing torque have an effect on vibratory frequency of spiral bevel gear.Three teeth contact model of spiral bevel gear, which would be used for contact analyzing was set up by APDL program of ANSYS. The dissertation has put forward a new method to solve the problems of analysis of contact stress and bending stress, and discussed differentia of contact stress and bending stress in condition of various loads, and also discussed the changes of contact stress and bending stress in a mesh cycle of a single tooth. There are no special demands to the finite element model by this method, and the results are always accurate. Based on the real contact state of gear drives, the dissertation has put forward a new loading method which can avoid the problem of stress concentration caused by loading concentrated force. The work of the load distribution among the teeth was done by ANSYS. This method is simple and easy to be carried out.