| In recent years, electric power is increasingly becoming an indispensable energy. Compared with traditional thermal power generation, the new wind power generation has the advantages in wide area, no pollution, and so on. This makes the research and development and manufacturing of wind power equipment become a hot spot. In the whole wind power system, the status of the planetary transmission gear box is very important, and in the gear box, the failure rate of the gear transmission accounts for 60% of the total failure. Gear box is generally installed in the tens of meters or even tens of meters in the air, in the gear meshing process,it’s easily be influenced by the wind speed fluctuations and environmental,the key issue of gear transmission system was in the manufacturing, assembly quality and its operation and maintenance level. Gear in machining is a highly complex parts, and at high speed, heavy load running gear, its working conditions are relatively poor than other parts. So once the gear transmission system of wind turbine is in trouble, it will cost a great manpower and material resources to repair or replace it. For this reason, it is very important to draw the load spectrum of gear transmission of the gear box and estimate the reliability life.This paper took the planetary gear transmission system as the research object, the establishment of three-dimensional model of gear transmission, use NX Siemens 8 software simulation module for flexible body simulation, the definition of materials for each part of the grid, after its application constraints, analysis of the results of backward action mechanics simulation. Analyzed and defined the gear as a flexible body, in order to make the simulation results closer to the actual situation, the gear to withstand the load is associated with wind speed and the wind in a certain period of time is obeys Weibull distribution, by MATLAB software to generate a group obedience of the Weibull distribution data and this data as simulation input load. Thus the time history of the load of the gear is obtained. MATLAB preparation of rain flow counting method of the program, extract the load cycle, the statistical component of the amplitude of the load, the mean and frequency, the establishment of transmission system load spectrum. According to the empirical formula and the fatigue property of the material, the Sa-Sm-N curve of equal amplitude fatigue value is established. Applying the Miner linear rule, the stress amplitude and the mean value of stress are extended to the two-dimensional probability density surface. The damage degree caused by the stress level at all levels of the whole working period is caused by the damage degree. When the sum of the damage degree is accumulated to 1(100%), the component is fatigue failure. The fatigue life of the stress concentration part of the driving system is analyzed and calculated, and the combined calculation of each working condition is combined with the fatigue analysis theory of the average stress correction, which can predict the life span of the gear transmission system. Provide the theoretical support for the fatigue analysis of gear transmission system. |
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