Finite Element Analysis On Portal Axle Of Super-Low Floor City Bus

With the speeded-up of urbanization in China, city scale and population is expanding sharply. Higher requirements of public transport system are proposed by increasing of residents' travelling. In order to improve the city-bus's transport capacity, major cities are gradually adopting low-floor and ultra-low-floor city-bus which have higher transport efficiencies. The key technology of the low-floor and ultra-low-floor city-bus different from ordinary city-bus is the Portal Axle. This can achieve lower floor height; improve the convenience of getting off and on and the transport efficiency.As one of the critical assemblies on low-floor and ultra-low-floor city-bus, Portal Axle do not only bear one-third of the vehicle's load, but also endure complex forces. It is relates to the vehicle's steering, handling stability, braking security and capability of transition. Therefore, to master the structural features of Portal Axle, to get a comprehensive understanding of its force status when it is in the operation and requirements on strength,stiffness,impact resistance and fatigue characteristics reliability, to design and develop products to meet the using requirements are very important.This paper made a city-bus with Portal Front Axle for the prototype. The three-dimensional solid model of front axle was framed by the three-dimensional modeling software UG. The finite element analysis model was obtained through importing the model into the finite element analysis software ANSYS. We found the positions of dangerous key points and the reasons of excessive stress value on key points through static stress analysis and intensity checking in accordance with the typical situation and proposed the correspond programs of improvements; We had a fatigue life analysis of Portal Front Axle in accordance with static analysis results and received the allowable cycle numbers on key points. The results showed that the front axle met the design requirements of fatigue life. Finally, a modal analysis was carried on by using ANSYS. The natural frequency of Portal Front Axle was obtained. Compared with the vibration frequency generated by road vibration, we got the result that the front axle's structure was reasonable and could meet the requirement of the low-floor and ultra-low floor city-bus using.Research results in this paper can provides reference for the development of China-made Portal Front Axle.