Ⅰ. The purpose and significance of project

1. Introduction

With the advancement of automobile manufacturing technology and the high-speed development of the whole automobile industry, the design and manufacture technology of drive axle are constantly improved and perfected. The development of automobile industry has driven the development of parts and components and related industries. As one of the key parts of automobile, the automobile drive axle has also been developed accordingly. Various manufacturers have basically achieve specialization and serialization in the process of research and development and production^[1].

China is in a relatively backward position in the research and manufacture of traditional cars, and it is almost impossible to catch up with those big automobile manufacturers in a short period of time. However, in the study of pure electric vehicles, the progress of our country is not too late. With years of experience and Ramp;D capabilities, our research is ahead of the world. In addition, oil as a non-renewable energy, if we can promote and use pure electric vehicles,which will also be of great help to solve the energy problem. For pure electric logistics vehicles, its market demand has always existed, and with more and more cities to strengthen the restrictions on fuel vehicles, the market potential is very large ^[2].

In addition, the drive axle, as the final transmission part of the automobile transmission system, is usually composed of the final drive, differential, half shaft, bridge case and other components, and has the following functions: deceleration and torque increase through the final drive; The direction of torque transfer is changed by the bevel gear pair of the final drive or the hypoid gear pair; the inner and outer wheels are turned at different speeds by the differential; and the load-carrying and force-transmitting effects are realized by the axle housing and the wheel. Its structural form and design parameters not only have a great influence on the reliability and durability of the automobile, but also have a direct effect on the performance of the vehicle, such as power, economy, ride comfort, passing, maneuverability and handling stability, etc. The detection of these performance can be carried out by virtual prototyping technology^[3]. Therefore, the study of driving axle design method is particularly important ^[4].