Study on time-varying meshing stiffness of helical gears with root crack faults based on improved potential energy method

Time-varying meshing stiffness is one of the important excitations of gear transmission system, and its accurate calculation is an important basis for gear dynamics research. This paper proposes an improved potential energy method to calculate the theoretical time-varying meshing stiffness of healthy gears and helical gears with root crack faults, taking into account the non coincidence between the tooth root circle and the base circle of the helical gear, as well as the angle of the tooth root transition circle, the simulation results of KISSsoft were used to verify the rationality and effectiveness of the improved method; analyzed the influence of basic parameters and fault severity of helical gears on time-varying meshing stiffness. The results show that the accuracy of meshing stiffness obtained by the improved method has increased by about 5%; changes in the basic gear parameters cause changes in the contact ratio, which in turn leads to changes in the fluctuation and average value of the gear meshing stiffness; the fluctuation of meshing stiffness is in the minimum value when overlap contact ratio is close to an integer, the fluctuation of meshing stiffness is in the maximum value when total overlap is near an integer; the variation of crack depth and angle leads to local attenuation of time-varying meshing stiffness of helical gears. As the degree of failure increases, the local attenuation of meshing stiffness becomes more pronounce and compared to crack angle, meshing stiffness is more sensitive to changes in crack depth. Compared with the traditional potential energy method, the improved method improves the calculation accuracy of the time-varying meshing stiffness of helical gears, which is highly practical in the accurate calculation of helical gear meshing stiffness excitation and provide the theoretical basis for the calculation of the meshing stiffness of helical gears.