| Electric shovel is the main exploitation equipment in the strip mine. It possesses many advantages: such as wide adaptability, highly stable, high efficiency and so on. Due to the unique position of electric shovel in strip mine and the national innovation need for large-scale equipment, some manufacturers begin to research on the technique of the electric shovel.In our country, we always adopt the traditional design method and copy the homogeneous product in the designing of electric shovel. As a result, we can not grip the key technique at all time, the price and the after service are controlled by overseas factories. Due to different strip mine has different performance requirement of electric shovel, the manufacturer has to improve on the function of existing product to meet the needs of different strip mine. For one product has provided with dissimilarity performance, the traditional design method is faced with difficulty. Although the method of finite element already come to fruition and be got widespread use, it is no application in the electric shovel design in our country. And so applying the finite element theory in designing of the mining excavator fit the demand of the national innovation and break the monopolization. It is an effective way of changing the low level of our electric shovel design and not griping the key technology.The paper aims at studying the 12m3 electric shovel's crawler frame of Fushun Mining Group. The crawler frame is a new design compared with other parts of the electric shovel, and so, the design of crawler frame is the key part of shovel's design and it decides to the time of the excavator to put into production. The intermediate cable excavator's stabilization is belong to local stability, its back body is a little tilted when it digging, so the load is quite complex on the guide wheel part of the crawler frame. Combining some disadvantage operation conditions when the excavator digging or locomotion, the paper studies on the behavior of mechanics and vibration of the crawler frame based on the finite element method. To further spread and apply the finite element method in designing of the electric shovel main research contents and research results originally in the paper are as follows:(1)The current situation and developing tendencies of electric shovel at home and abroad, the developing prospect of finite element theory, the developing situation and the difficulty of the design of excavator in China are reviewed, based on studying a large number of references abroad and home. Then the effective method of solving the problem is suggested.(2)In this paper, the applications of the finite element theory in the crawler frame designing and analysis are studied, and the theory in analysis of crawler frame is confirmed.(3)The paper establishes two models in Pro/ENGINEERING based on the crawler frame analysis, the overall project of cable shovel and the load characteristics of crawler frame. One is the accurate model using for the measurement of analysis parameters and the dynamic simulation of the excavator, the other is the simplified model using for finite element analysis. Then, the paper studies the data transfer method of model and the flow of dealing with model.(4)The paper confirms some disadvantage operating conditions using for the crawler frame analysis, the crawler frame mechanical features, the load, the analysis model, the stress distribution and the deformation are presented under the working conditions. Through the structural analysis, the stress concentration is fond at the connection of crawler and base frame. In atrocious working condition, the point of stress concentration will emerge some questions. The condition of the three point supporting is the most dangerous in the disadvantage operating conditions, and the stress is higher and the intensity is insufficiency at the part of the second and the sixth thrust wheel hole. It is deformed too much and has defect places near the guide wheel of the crawler frame.(5)Some improvements are carried through in the defect locations based on less modification, remarkable effect, simple, acceptable, etc. It gets remarkable effects and avoids trouble after drilling on the defect locations near the guide wheel. In the coupling location crawler frame and base frame, the improvement of fillet is applied, which get remarkable effects. The stress is reduced obviously after adding bulge at the part of the second and the sixth thrust wheel hole. If calculate the effect of the thrust wheel assembly, the stress would decline further.(6)The model's mechanical features are analyzed when the mining excavator is working, the model is used in modal analysis and the paper gets some crawler frame's modes of vibration and its natural frequencies. At the end of the paper, the conclusions of no resonance phenomenon based on the results of modal analysis are presented.The research make the manufacturers know the stress distribution and deformation of the crawler frame under different conditions. It solves the problem of lacking strength which proves the feasibility and economic value applying finite element method in our mining excavator design. It is in favor of the improving our excavator designing, griping the key technology, accelerating the process of independently innovation. The methods and process of this paper is also the reference of other parts designing which has applied cost in structure modification and functions improvement. |
