| Vertical mill reducer is the core component of vertical mill, and its dynamic characteristics, fatigue life and reliability are the main measure index of vertical mills’ comprehensive performance. During grinding cement, ceramics and other industrial raw materials, the vertical mill is operating in very harsh condition. Therefore, the dynamic characteristics and reliability of vertical mill reducer are proposed a higher level requirement. Nevertheless, the dynamic load of gear system is relatively complicated, which bings many difficulties to the accurate analysis on dynamic characteristics of vertical mill reducer. Moreover, the gear transmission part is liable to fatigue failure and reliability failure under the effect of dynamic load, and it will seriously affect the normal operation of vertical mill reducer. Thus, the analysis on dynamic characteristics, fatigue life of vertical mill reducer has important theoretical significance and engineering value for improving its comprehensive performance.The thesis is combined with the main research task of The National Key Technology R&D Program(2013BAF01B04). The dynamic excitation simulation, vibration characteristics simulation, fatigue life prediction and reliability analysis of the gear system in vertical mill reducer are investigated comprehensively in this dissertation. The main research work in this paper can be summarized as follows:① The kinetic models of gear transmission in vertical mill reducer are established based on the analysis of supporting stiffness of bearing and contact stiffness of gear pairs. By solving the vibration differential equation, the dynamic excitation are obtained. Then the effects of eccentricity error and sun gear floating on load sharing behavior in planetary gear transmission of vertical mill reducer is investigated.② The gear system coupled dynamic model of vertical mill reducer is built by using the numerical simulation software ANSYS. The natural frequency and natural mode of gear system are obtained by finite element modal analysis, then the approach rate of natural frequency to excitation frequency is calculated. On these basis, the dynamic response of vertical mill reducer is analyzed by mode superposition method, then the structure-borne noise of gear box is evaluated.③ Aiming at the planetary gear transmission of vertical mill reducer, the loading spectrum of fatigue life analysis are acquired. Referring to the GL standard, the material’s S-N curve of gears is calculated. According to the stress results of static contact analysis, the fatigue life prediction of planetary transmission gear in vertical mill reducer is conducted with ANSYS/Fe-safe based on fatigue cumulative damage theory, and then the influence rule of surface roughness and load on fatigue life is studied.④ The bending fatigue reliability of bevel gears, helical transmission gears and planetary transmission gears in vertical mill reducer is analyzed by the second moment algorithm. Using quick response surface method, the reliability analysis model of planet carrier is established, and the degree of fatigue reliability and sensitivity is obtained. Then combining the two fatigue reliability, the reliability analysis model of gear transmission system in vertical mill reducer is built, and the fatigue reliability of transmission system is analyzed. |
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