Dynamic modeling of multistage gear transmission system box coupling

With the deepening of research and the improvement of computer performance, the research object of gear system dynamics has experienced the transition from a simple system composed of a pair of gears to a complex system including gears, gear shafts, bearings and boxes. Generally speaking, gear system can be divided into two parts: transmission system and case. Transmission system is a system composed of gears, gear shafts and bearings, which is used to transmit motion and power. Transmission system can also include coupling, flywheel, prime mover and load related to gear transmission.

Some scholars use commercial software to establish the full finite element model of the complete gear system including the transmission system and the box, and carry out the system dynamics simulation. Li A full finite element model of a wind power gearbox is established, and the static transmission error curve of the gear pair under the assembly condition is obtained by using the contact finite element method. With the static transmission error as the excitation, the dynamic meshing force of the gear pair is obtained through the lumped parameter model, and then the dynamic meshing force is applied to the meshing lines of the gear pair in the full finite element model of the gearbox as the load excitation It’s on. Zhu et al. Established a full finite element model of a marine gearbox, applied the dynamic meshing force calculated by the lumped parameter model to the meshing line of each gear pair in the full finite element model, predicted the vibration acceleration and noise of the gearbox, and compared with the experimental results. Lu Bo et al. And he et al. Also studied the dynamic characteristics of the complete gear system by using the similar full finite element method.

At present, the dynamic substructure method is the first choice to establish a complete dynamic model of gear system. The dynamic substructure method originated from the study of the natural vibration of aircraft and wing, and began to be used in the dynamic modeling of gear system in the late 1980s. In the dynamic substructure method, the dynamic model of transmission system is generally established by lumped parameter method or transfer matrix method, and the dynamic model of box body is generally established by finite element method (modal condensation is usually used to reduce the degree of freedom of the model). Finally, the system coupling equation is established according to the coordination relationship of the connection interface. The dynamic substructure method has the following advantages

1) Each component (substructure) can be designed and analyzed independently;

2) Each component can have different mechanical properties, such as linear or nonlinear;

3) Different methods can be used to establish the mathematical model of each component, such as lumped parameter method, transfer matrix method or finite element method;

4) Modification or reanalysis of each component will not affect other components;

5) Each component can be tested separately and compared with the analysis results;

6) It is helpful to establish the dynamic model of complex system.