Research On Dynamic Characteristics Of Two-stage Gear Transmission System With Fault Parameters

Gear system is a mechanism which has been widely used to transfer movement and power in everyday life. There will be a variety of fault in the long-term use of gear system, and the presence of the fault will make motion system very complicated. So it is necessary to explore the dynamic characteristic of gear system with fault.The main content of this master thesis is as follows. The powerful 3D modeling provides us some essential parameters of a two-stage gear transmission system. A complicated two-stage gear transmission dynamic model with fault is established when the gear backlashes, time-varying meshing stiffness, meshing damper and synthetically meshing errors are considered. After the coordinates are changed, the dimensionless method is used to get a two-stage gear transmission dynamic equation. Equations about impact fault, stiffness fault and wear fault are obtained when the perturbation theory in chaos control is considered. The varying step Runge-Kutta method is employed to perform numerical simulation of the dynamic model.Bifurcation diagram, load diagram, impact diagram, phase diagram and Poincaré diagram are used to analysis the impact caused by the fault.The results show that: the load and the amplitude in a two-stage gear transmission system without any fault change rarely when the system doesn’t enter into chaotic motion, but they change drastically when the system enters into chaotic motion. So non-chaotic meshing frequency range described above should be chosen to reduce impact and noise, and improve stability of the system. The number or the amplitude of impact fault in a two-stage gear transmission system can affect movement characteristics in high meshing frequency range. And the location of impact fault will affect movement characteristics in low meshing frequency range. The existence of impact fault will change the bifurcation’s critical value in the system.The number of stiffness fault, the amplitude or the location of stiffness fault in a two-stage gear transmission system will affect movement characteristics in low meshing frequency range. The location of wear fault in a two-stage gear transmission system can affect movement characteristics in low meshing frequency range. The amplitude or the number of wear fault in a two-stage gear transmission system can affect movement characteristics both in high and in low meshing frequency range.