| With the rapid development of economy, the consumption of land resources has a large scale, and the research on the offshore platform have been paid more and more at ention,offshore platform mining began to turn from the previous offshore,therefore put forward higher requirements on the offshore platform.Since the working environment of ocean platform is quite harsh, the study on reliability of the offshore platform becomes a challenging and desired subject. The economic and reliability index combined as a measure of the success of a product index for the structural design of offshore platform gear box, how to allocate the transmission better than transmission system and ensure the strength to meet the requirement, in the case of large transmission than the less vibration, ensure the efficiency of the system has become a new research direction.Due to the planetary gear system with small mass, high space utilization rate, high transmission ratio, high efficiency and can effectively use the power diversion, coaxial advantages for offshore platform gear box in a small space, the transmission than large, high power transmission. For large transmission ratio gear box, the distribution of transmission ratio directly affects the load capacity and service life of the gear box. Therefore, it is necessary to study the distribution of the number of teeth.This topic for offshore platform three NGW planetary gear structure and its motion is the torque to the planet to the sun wheel, planet wheel transfer to the planet carrier, planet carrier through a spline transfer to a sun wheel shaft, the gear box of each tooth number ratio as the optimization object, according to the tooth surface contact strength of principle of distribution of large transmission ratio, and in the use of each planetary gear train number of planetary gear of planetary gear train gear ring diameter and and its maximum volume and the influence. The bending safety factor and the contact safety coefficient of the gear were checked, and the stress distribution of the sun wheel shaft was calculated by using FEMFAT to calculate the stress and fatigue damage. Finally, based on the SIMPACK software, the dynamic simulation of the planetary gear box is carried out, and the vibration displacement and the vibration velocity of the gear box are solved.The main research contents are as follows:(1) In two adjacent contact strength principle, with wide diameter ratio, the load sharing coefficient as the constraint, the three ring gear diameter and minimum and three ring gear volume and minimum as the optimization goal, based on the MATLAB software, the development of a reliable assignment of the tooth number ratio of the system.(2) Under the help of MASTA software build gear box model, the calculation of bending stress and contact stress that the value is less than the bending limit and contact stress limit, and the gear bending safety coefficient and contact safety coefficient are calculated.(3) According to the nominal should force method and the linear cumulative damage theory, based on the yield principles to check the strength and fatigue analysis of the sun wheel shaft, using femfat software calculate the sun wheel shaft of the maximum tensile force and maximum cumulative fatigue damage results. The rationality of structural design is monitored by stress distribution chart.(4) The dynamic model of the gear box transmission system is modeled by the integrated finite element software. The sensor is set up on the gear box, and the vibration displacement and the vibration velocity of the gear box are simulated and analyzed.According to the number of teeth of the gear ratio distribution for three straight tooth planetary structure, especially in the demand for large transmission ratio of the project in the distribution of the ratio of the number of teeth, the distribution of planetary gear train number of planetary gear. This method can be applied to some cases of marine gear box and it also provides reference value for other engineering machinery. |
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