Research On Heavy Vehicle Wheel-side Reducer

As an end transmission of the driving axle in heavy vehicles, wheel-side reducer is capable of reducing speed and generating large torque. It decreases the load exerted on the gearbox, transmission shaft, differential gear, main reducer and other components without changing the total speed ratio. The wheel-side reducer has found wide applications in fields of heavy-duty vehicles and engineering machinery in that it provides a larger ground clearance and higher carrying capacity due to contracted dimensions of the driving axle. Therefore, the investigation of wheel-side reducers has a practical and theoretical significance for the development of related areas.This paper focuses on the following aspects.First of all, the working principle and requirements of the wheel-side reducer are presented based on the example of driving axle. Failures occurred on the planetary gear and planetary axle of wheel-side reducer after test experiment. The failure causes of the planetary gear mechanism are analyzed and corresponding precautions against the failures during the design, manufacturing and maintenance of the wheel-side reducer are proposed, which is beneficial to the operating and maintenance of the wheel-side reducer.Secondly, it is generally difficult to build a model of transmission mechanism when investigating the planetary gear transmission system with finite element software ANSYS. In this paper the structural model is built with Pro/E and then imported into ANSYS through data interfaces, simplifying the modeling process and saving time. With the single database, parameterization and relational expressions in Pro/E, the involute gear profile is obtained. This profile thus created approximates the actual tooth form and improves the computational accuracy.Once again, the gear contact in transmission is analyzed with ANSYS based on the transmission model built in Pro/E. Limited by the processing capability of the computer, only one couple of gears involved in engagement are analyzed in this paper and the grids of the contact area are refined in order to improve the analysis accuracy. The contact pair is determined by the gear contact ratio on the basis of actual situation and then the stress contour is obtained through applying constrains and loads on the transmission system. The part bearing the maximum force is thereby located and the analysis result is verified by comparing to the calculating result. Besides, the stress contour of the planetary axle and planetary carrier bolt holes is obtained by analyzing the model of the planetary carrier built with the bottom-up method in ANSYS. Deformation caused by insufficient strength is founded which affects the whole transmission system.Finally, the insufficient carrying capacity of transmission components can be found with finite element method. It is concluded in this paper that the load-balancing mechanism is useful to improve the carrying capacity of transmission system through analyzing its principle, structure and measures. In contrast with static models built in most current researches, the dynamic model of transmission system is built. Taking the actual stiffness and damping into consideration, the dynamic load balancing model is formulated, which provides the theoretical basis for the design of planetary gear transmission systems.