Structure Analysis And Improvement Of A Two-speed Automatic Transmission Housing For Pure Electric Vehicle

With dwindling non-renewable resources, environmental pollution and otherissues becoming increasingly prominent, China’s automobile industry is undertremendous pressure of energy saving, and urgently need to rationalize the structure ofautomotive products to meet the needs of a sustainable society. Because of theadvantages of zero emissions and low noise, pure electric vehicle (PEV) has currentlybecome a research hotspot in many countries and is a new important kind of greentransport. In order to solve energy and environmental issues faced by the sustainabledevelopment of China’s automobile industry, development of new energy vehicles,especially pure electric vehicles, has great practical significance.Transmission has an important impact on PEV’s vehicle performance and isindispensable component for transforming power and controlling speed when thevehicle is travelling. As a basic component, transmission housing supports andprotects the gear transmission mechanism. In the process of working, due to driving ofmatching gears, transmission housing bears relatively large load. In order to ensuretransmission’s normal operation, housing should have excellent static and dynamicperformance. As the structure is complex and load is extremely uneven, it is difficultto calculate the strength and stiffness of housing by traditional analytical method. Inview of above mentioned difficulties, this paper puts forward finite element method toanalysis the structure of transmission housing. In this paper, the housing of atwo-speed automatic transmission (2AMT) which is applied on a domestic pureelectric vehicle was studied. Static and dynamic analysis was conducted by ABAQUS.And the structure of housing was modified based on finite element analysis (FEA)results. The main work and achievements accomplished in this paper are as follows：1) Study the structure and working principle of2AMT. Conduct force analysis ofgear transmission mechanism in limited conditions and acquire the magnitude anddirection of axial and radial forces in low and high gear conditions.2) Set up the3D model of transmission housing by CATIA and simplify itreasonably according to the requirements of FEA. Set up its finite element model byABAQUS. This process includes: meshing, definition of material properties,application of bearing loads and displacement boundary conditions.3) Calculate housing’s finite element model by ABAQUS/Standard, acquire thestress and displacement distribution contours and confirm the weak spots on housing. Then the structure of housing is modified. After repeated analysis, the results showthat the strength and stiffness of modified housing is largely improved. Based on themodified model,2AMT prototypes are manufactured and durability experiment isconducted on testing bench. The results show that the strength and stiffness oftransmission housing meet the requirements.4) Enforce modal analysis under free state and constrained state. Acquire thefront ten natural frequencies and modal shape. After analysis and computation undercommon speed, the excitations inside the transmission won’t lead to resonance.Transmission has a excellent dynamic performance.