The Design And Research Of Front Axle In Medium Duty Commercial Vehicle

FAW R&D shall put forth a brand new generation of medium-duty trucks in 2007, to fulfill FAW Group's schemes of development. The new medium-duty trucks are designed to gradually replace the current medium-duty FAW trucks in the upcoming future, and finally catch up with the European commercial vehicles in terms of technological design. To complete such a quest for new trucks, a fresh development for integral non-independent front-axle assembly is on its way.In the front-axle assembly of the past, usually the design of Axle Load tends to be small, which is not able to meet the demands of the axle load of the new trucks. Consequently, a brand new front-axle assembly needs to be developed. In the new assembly, not only the structure of main parts needs to be re-designed, but also the layout of wheel, which breaks through the traditional design and applies the modern advanced UNIPAC from abroad. It makes the layout with noticeable benefits, much more integral and lighter. In addition, an innovative design on a number of parts on front-axle wheel that allows both disc brake and drum brake to work. That is to say, it is possible to adapt the whole wheel parts in different ways without changing any single one of them, by which multiple options are available. Such approach brings a remarkable significance and elevates the production to a new level. For different wheel bases, the front-axle design employs two types of Steering Trapezoid Structure. Steering knuckle arm will be equipped with various mounting holes to make said steering trapezoid structures work. It helps to enhance the main parts with more compatibility, and accommodates the requirements of the vehicles with different wheelbases. In the whole design process of new front-axle, accurate comparisons of different samples from home and abroad must be done in regard of Strength and Stiffness, together with sizes of sections, in order to optimize the front-axle design.With the complete design of the front-axle assembly, testing assembly on test-beds must be carried out, especially on strength, stiffness, and fatigue life of all main parts. All test-approved assembly shall be installed into a completed vehicle, and then carry through the road test method in order to check reliability, durability and adaptability of the front-axle and its parts. Such procedures will put the validity of the front-axle design in a test as a whole, and as well a practical way of finding solutions to the problems and errors discovered in the testing. What is more, testing is also a method to examine presumed statistics by calculation and recorded statistics by actual test, and keep them in accordance by necessary adjustment for final applications of the front-axle.In a spirit of providing reliable references for the assembly and its parts'developments in the same and similar fields, this thesis shall contribute a summary of the methods of design and analysis in the development of front-axle assembly in writing. F5N is hereby set as an example in this thesis to further illustrate all the designs and testing methodologies of the front-axle assembly, together with an overview of related development in the past.This thesis has six chapters.In Chapter 1, the thesis shall begin with an overview of the front-axle assembly, and then introduce a comparison of different layouts of front-axle assembly at home and abroad, and finally enlightens the path of the basic design of the front-axle assembly in this thesis.In Chapter 2, the layout of the front-axle assembly shall be elaborated, along with the introduction of PRO/E software, and illustrations of the main parts of the front-axle assembly in three dimensions.In Chapter 3, the thesis will cover the checking of strength on main parts of the front-axle assembly.In Chapter 4, the thesis will carry out a spatial kinematics analysis in the light of front-axle calculation theory, mechanism, and 3-D module by PRO/E software; and it shall use NASTRAN software to perform finite elements analysis of the main structural parts.In Chapter 5, the thesis will discuss the testing, which no calculation and simulations can replace. Based upon the calculation theory and the analysis of finite elements, an assembly testing is performed on test-beds, and the testing result proves that both the design and the calculation are correct and reason.In Chapter 6, the thesis shall conclude with a summary and also make remarks of the trend and direction of front-axle assembly development in the future.