Performance Analyze And Structural Optimization Design Of The Planet Carrier In Yaw Gearbox

Planet carrier is the parts of planetary reducer which withstand the maximum torque. It is great influence to the load distribution between the planetary. Therefore, how to get the stress and displacement of the planet carrier accurately and to improve its structure, to research a lighter and bigger stiffness carrier structure is very important which has significance for improving the high reliability and lightweight design of the planetary gear box.This paper derived from the National Supporting Program "7MW-grade Wind Turbines and Key Parts Design and Mass Production Technique". The planet carrier in wind yaw gearbox is researched. The equivalent model of the mesh stiffness, support stiffness and spline joint surface are established. The equivalent FE model is established and static strength analysis is made. The factor of structure parameter sensitivity which influence for the stress and deformation of planet carrier has been demonstrated. The topology optimization of the planet carrier is completed, in which the minimum compliance and volume fraction is as objective function respectively. Based on the Material distribution, the conceptual model is obtained, from that the optimal structural of the planet carrier is designedFirstly, according to the force transmission path, the force of the planet carrier and other related components in yaw gearbox is analyzed based on speed, torque and force balance principle. Then the bearing reaction of planetary axle is calculated according to the given rated speed of motor and gearbox output torque.Secondly, the mesh stiffness is calculated by the finite element method, and then the gear meshing stiffness is equivalent to a spring along the direction of the meshing line. The bearing support stiffness is calculated by using the concise calculation formula, and then the bearing support stiffness is equivalent to the radial springs. The numerical of spring is lied on the number of contact Roller Bearing. The equivalent of the spline joint surface is obtained by using a variety of layout of spring.Thirdly, the finite element strength of planet carrier is analyzed which consider the gear mesh stiffness and bearing stiffness. The factor of structure parameter sensitivity which influence on the stress and deformation of planet carrier has been demonstrated. The result show that the bearing stiffness has a little influence for the stress result and it is can’t be ignored. The different equivalent of the spline joint surface model has a greatly influence for the stress and deformation of planet carrier. Gear mesh stiffness can be a constant value in the model because it is almost no effect to the result. It can get an optimum structure when the distance of Double-walls is90millimeter and diameter of hole is46.5millimeter.Finally, the mathematical model of the topology optimization for the planet carrier are established, in which the minimum displacement and the minimum compliance are as the objective function respective. The structure topology optimization for the planet carrier is conducted using Hyper works analysis platform. Based on the Material distribution, the conceptual model is obtained, from that the optimal structural of the planet carrier is designed consider the factor of mechanical properties and manufacturing processes. Comparing the performance of the new design one with the original, the property of planet carrier has a greatly improvement. The minimum compliance and the minimum displacement are as the objective function respective, the weight amplitude is reduced to18.14%and11.83%, the displacement to15.61%and16.66%while one stress to13.16%, another stays invariable. This method has guiding significance for design and improvement of planet carrier.