The Dynamic Characteristics Analysis Of Transmission Box Based On Rigid Flexible Coupling

Automobile's gearbox plays a role of a backbone structure of auto's transmission. Various kinds of parts are installed inside the box, including coolant and lubricating oil gallery, proper working spaces are also provide in it. Outside of the box, the driver of the transmission and the shifting mechanism are packaged and connected with the whole vehicle. Automobile's gearbox works in a very bad environment, is always under the periodic variation forces of the gear, and the box is often in complex stress state, caused by pull, pressure, bending, and twisting, as well as the vibration. Therefore, the study of transmission, which is one of the key components of the automobile transmission system, is of great significance to the study of the automobile's gearbox.The thesis studies a certain transmission box, whose static strength has been discussed and passed the test, but the strength failure happened to it in reality. In this thesis, we establish a rigid-flexible coupling dynamic model and a finite element model of gearbox, using the method of dynamic characteristics analysis of box based on dynamics rigid-flexible coupling. Firstly, we analyze the static strength of gearbox and give static strength experiments on it, the results indicate that: gearbox maximum stress satisfies the requirements of box strength and according to the results simulation and analysis results are confidence.Then, simulating the dynamic loads based on rigid-flexible coupling dynamic model, we study the transient behavior of the certain box under simulating dynamic loads on hole for mounting bearing of the box for the problem that the dynamic strength failure happened to it in practical use. The results show that the box maximum stress does not satisfy the standards of box strength in many cases, the structure is unqualified.Finally, aiming at the structure strength weak of the installation of intermediate shaft left bearing on the case of transmission, The structure scheme of adding reinforcing bars to the transmission case is presented. According to the scheme, the improvement of the model and the verification of the transient characteristics are carried out. The results show that the added reinforcement can share the load to a certain extent. The maximum stress is in accordance with the strength condition of the box, and the scheme is feasible.