Finite Element Analysis And Optimization Of The MW520 Magnesium Alloy Transmission Case

Normally, the automobile moving mainly relies on the stable power output of the transmission system. In this process, the motor interacts with the transmission to accomplish complex speed conversion and power transmission. The transmission can make the motor to play its best performance, whose function is to convert the output speed of motor to the input speed through the flywheel, clutch, etc., and to export different rotational speeds in accordance with the requirements of different drive ratios to satisfy the requirements of different speeds and tractions. The transmission case should have sufficient strength and stiffness to resist the external loading, which is the key factor affecting the reliable operation of transmission assembly and the stable power output of gear transmission system. Insufficient stiffness, will cause the excursion of the bearing’s location, which causes its abnormal wear and damage, greatly reduces its usage life. At the same time, it will cause the dislocation and unbalanced loading of gear drive, increase the transmission noise. While insufficient case strength, means its insufficient carrying capacity, which will cause the avulsion of the transmission case, influence automobiles’ safety driving.Magnesium alloy is a lightweight material in the field of metal alloy. It has many characteristics such as high specific strength, high specific stiffness and good cushioning effect and heat dissipation ability. AZ91 D is regarded as a kind of green and environmental structural material, especially for its low density and high loadability. Its application to industrial products can greatly reduce products’ weight and improve their performance. In the automotive industry, the weight of cars is one of the important factors that affects oil consumption. With the increasingly serious environmental problem in our country, and the national energy conservation and emissions reduction policy rolling out, the concept of low-carbon economy popular support continually, to reduce fuel consumption, improve fuel economy and realize the automotive lightening have become one of the direction of the automobile manufacture enterprise actively explore and research.In this paper, the material of transmission case is AZ91 D magnesium alloy. Using the software of UG establishes the 3D model of transmission assembly. Considering the contact nonlinear finite element theory, using the software of HYPERMESH establishes the finite element model and improves elements quality by check skew, length, warpage and jacobian. Establishes the power system model of the MW520 magnesium alloy transmission by MASTA, at the same time, set the speed and running time. In the MASTA applies 2.5 times load on the system model. Extract the load spectrum from the system bearing hole and applies in the finite element model by the software of HYPERMESH. Research the stress distribution of the transmission case under the 2.5 times load spectrum and the impact load spectrum. Optimize the structure of the high stress area. Verify the transmission case of AZ91 D magnesium alloy material met the work requirements.