Simulation On The Dynamic Transmission Error Of A New Type Of Variable Tooth Thickness Gear System With Eccentric Gears

This research topic comes from the project of national natural science fund(51275538). Eccentricity is the main source of the periodic transmission error and cyclical backlash of gear system, which affects the dynamic transmission accuracy of gear system directly. The error and time-varying stiffness is usually simplified as the harmonic function or obtained by experimental data in the discrete-model been used widely, and the clearance is simply assumed as constant or normal distribution. The finite element model of gear system has been established and the dynamic transmission error of gear transmission system is studied in this paper, in which the eccentricity and its phase of standards/variable tooth thickness gears are considered. This topic has important theoretical significance and application value. Followings are the main content:① The finite element model is verified by the results of dynamic transmission error with no gear eccentricity. Considering the factors about static transmission error and time-varying clearance mainly caused by eccentricity and variable load,the dynamic transmission error is studied. The dynamic transmission error jumps when the direction of load changes, and the jumping amount is same as the value of clearance for the moment. When the frequency of load is higher(meshing frequency), the dynamic transmission error distributes in an interval, the under outline of which is coincide with the static transmission error approximately, and the upper outline is coincide with the static transmission error overlaid with clearance approximately. Besides, the transmission error caused by deformation of gear tooth should be considered. The same time, with the increase of clearance impact increases accordingly, which affect the dynamic transmission error.② The finite element equivalent of bearing is studied,then the finite element model of a standard cylindrical spur gear system which contains shafts and bearings is established. The effect of global damping constant, load and speed on dynamic transmission error of gear system is discussed. Considering gears with double eccentric,elastic deformation of bearings and shaft,the dynamic transmission error is researched,by which we discover that the contact force increases sharply, and then the bending deformation of shaft makes the actual center distance increases, which affects the transmission error of gear system.③ The finite element equivalent of spline in the new type of gear system is researched, then the finite element model of the new type of variable tooth thickness gear system including shafts, bearings and spline is established. Under the varying load conditions, dynamic transmission error of this gear system is studied with time-varying clearance, which provides a comparing foundation for the analysis of controlling clearance with the variable tooth thickness gear system in this paper. Based on the principle of clearance controlling of the new type of variable tooth thickness gear system, the theoretical formula of static transmission error of this gear system is modified and verified. Considering gear eccentricity, time-varying clearance, time-varying load, elastic deformation of shafts and bearings, the dynamic transmission error of the new type of variable tooth thickness gear system is studied, and the results show that the effect is remarkable in controlling clearance.