# Current problems in the study of gear drive system dynamics

After nearly a hundred years of continuous exploration and research, the dynamics of gear transmission system has developed into a complex theoretical system with interdisciplinary, experimental and theoretical integration. Its application range includes: Calculation of dynamic load, evaluation and prevention of vibration and noise, state detection and fault diagnosis, relationship between system parameters and dynamic performance, load identification and dynamic design, etc noodles.

It can be seen from the research literature that although scholars at home and abroad have carried out nearly 100 years of research on the research work of this paper, namely, the dynamics of gear transmission system, there are still several problems as follows:

(1) At present, in the process of nonlinear dynamics modeling of involute spur gear transmission system, it is generally assumed that the load of gear is uniformly distributed along the direction of tooth width and the direction of meshing force is always the same, so the system is simplified as two-dimensional plane motion, but the assumptions and simplified boundary conditions of these models are not clear. With the development of the gear transmission system towards high speed and heavy load, the vibration of the gear transmission system becomes more and more serious. The vibration form of the gear transmission system is more complex, including not only the transverse and torsional vibration but also the swing vibration. At the same time, the direction of the meshing force will change with the change of the center distance and the meshing state of the tooth surface and the tooth back. Therefore, it is still necessary to further study the influence of the change of the center distance of the gear and the change of the meshing state of the tooth surface and the tooth back on the direction of the meshing force, and to establish the coupling nonlinear dynamic model of the yaw of the gear transmission system.

(2) At present, in the gear nonlinear meshing model, the backlash is generally fixed, and the meshing stiffness is obtained by quasi-static method and presents periodic and time-varying characteristics, which are the input conditions of the nonlinear dynamic model. In fact, these factors change with the actual movement of the gear transmission system. For example, for the gear rotor system with small bending stiffness or large load of the transmission shaft, the change of the center distance increases, thus increasing the impact on the tooth side clearance; for the gear transmission system under no-load condition, the meshing state of the tooth surface and the tooth back occurs alternately, and the direction of the meshing line changes constantly, thus causing the dynamic change of the meshing stiffness. Therefore, it is still necessary to study the influence of the actual motion state of the gear transmission system on the meshing parameters such as backlash and meshing stiffness, so as to analyze the coupling effect between the dynamic change of the meshing parameters and the vibration response of the gear transmission system.

(3) At present, the research of tooth profile modification based on the dynamic characteristics of gear transmission system is still in the exploratory stage and rarely used to guide the design. The study of tooth profile modification based on the dynamic model of the gear transmission system can truly reflect the influence of tooth profile modification parameters on the dynamic characteristics. In the previous studies, the dynamic model of the gear transmission system is relatively simple, and the nonlinear model of the degree of freedom only considering the torsional vibration is generally adopted. The simplification of this model will have an impact on the modification results. In addition, the influence of tooth profile modification parameters on meshing stiffness is generally calculated by means of finite element analysis software, which reduces the calculation efficiency. Therefore, it is still necessary to further study and optimize the tooth profile modification based on the accurate dynamic model, and to calculate the meshing stiffness of the tooth profile modification gear with the analytical method.

Scroll to Top