Reliability Evaluation And Optimization Design Of The High Power Reducer Based On Earth Pressure Balance Shield

As China's economic development and the accelerated pace of urban construction, the shield gets the fast development all over our country. Shield tunneling method is a way which uses the shield machine to excavate tunnel under the ground. When it is working, it is able to prevent soft ground surface collapse or maintain excavation face stability, while, keeping the excavation and lining operations safely, then forming the tunnel once. Today, the economy developed rapidly, more and more construction units first select the shield to replace the inefficient traditional excavation method for tunneling.As one of key components of the shield, reducer is the important function parts to drive the cutter. It connected to one side with the hydraulic motor while connected another side to the spindle drive gear, which is the connection between the hub. Reducer is not only plays the role of transfer movement and power, but also impact of the load bearing in the case of an emergency braking situations. Because its special environment for varying load condition and it works under the ground, demands to have high reliability, light, apt to maintenance and economy. However, the reducer that design and manufacture in domestic fails to meet the above requests. Therefore, reliability assessment and parameter optimization design of the 3-stage planetary gear reducer become one of the great urgent tasks.The thesis subject is supported by National 863 Plan Project. Regarding the transmission system of 3-stage planetary gear as object, research the reliability assessment and optimization design of parameter of the system. It has offered the method with rational science and theoretical foundation for the fact that the production of the reducer designed and made in domestic.Concrete research work is as follows:â‘ Based on FMECA, the block diagram of system reliability and the fault tree model diagram should be established, they are the basis of reliability assessment later.â‘¡The contact element and the bending element of the gear and the contact element of the rolling are analyzed based on reliability analysis. According to the prediction of reliability and the distribution of reliability, system reliability model should also be established.â‘¢Using the Optimization Toolbox of MATLAB software, optimize the single-stage optimization model. Reliability optimal design of the rolling is also calculated. And we make a finite element analysis by using the ANSYS-WORKBENCH for the third-stage contact fatigue model after optimization.â‘£The results are given after optimization, and are compared with the original results, proving that the methods of reliability assessment and parameter optimization design are scientific and reasonable.