The Design And Finite Element Analysis Of Torsion Bar Of The Cab Of Medium-sized Truck

The cab of the medium-sized truck has been flattened. In order to facilitate maintenance and repair of engine, the cab must be able to flip forward. The cab tilting mechanism must be needed because manpower is not strong enough to achieve its tilting.The cab tilting mechanism of the majority of medium-sized truck is mechanical and torsion bar-type dual. One of the important parts is the torsion bar spring on the tilting mechanism. The elasticity of torsion bar is the main power that makes the cab tilting. Therefore, the performance of torsion bar spring is directly related to the quality of cab tilting. With the rapid development of automobile industry, the requirement for the performance of torsion bar on the tilting mechanism is more and more high. This makes the traditional method of calculation and design unable to meet the requirements of modern design. The emergence of electronic computer and the rapid development of the finite element method make a new revolution for the analysis of the performance of torsion bar structure. The finite element method for stress analysis of the cab tilting mechanism has great significance for enhancing performance of torsion bar and increasing market competitiveness.In this paper, the tilting mechanical hardware for the cab of the medium-sized truck was designed according to the actual working conditions at tilting time and the size of the truck frame and cab. Based on the principles of ergonomics, the torsion bar, which is the key part of the tilting mechanism, was designed. And the other parts of torsion bar were designed at the same time.The tilting mechanism and its load were appropriately simplified. The finite element mode of the torsion bar was set up in the finite element software Hypermesh. Then other finite element software Patran and Nastran were guided into. The corresponding boundary conditions and load conditions were imposed on the torsion bar and arm of force. A static analysis was run. The position of stress concentration was identified in the torsion bar and arm of force. Then the transition radius of the torsion bar was optimized. At last the materials composition, hardness, metallographic analysis, static experiment and fatigue experiment were made on the torsion bar. The experiments testified the validity of tilting mechanism design and its finite element analysis.This research systematically accomplishes the design of tilting mechanism and torsion bar and the static finite element analysis. The whole project provides referential experiences for the similar research of tilting mechanism in other types of automobiles as well as the further optimization of some relevant size of the torsion bar.