Research On Lightweight Design Technology For Large Scale Yaw And Pitch Gearboxes

Yaw and pitch gearboxes are the key parts of the yaw system and pitch system,their performance and reliability directly influence the operation quality andefficiency of the wind turbine. Due to the particular working conditions, yaw andpitch gearboxes often require highly both in structure and performance. Requirementsof their design are not only high load capacity and long service life, but also have theadvantages of small volume, light weight and compact structure. At present, yaw andpitch gearboxes for the domestic large wind turbine mostly adopt multistage planetarygear transmission. In this paper, combined with their working conditions, aimed atdesign requirements of lightweight and high reliability for yaw and pitch gearboxes,key technologies of the planetarygearbox are studied. The main works are as follows：1. Gear meshing force and torque of basic components for the power spittransmission system are analyzed, force of rolling bearings for the planets and force ofshafts for the basic component are analyzed; based on the national standard“Calculation methods of load capacity for involute cylindrical gears", combined withthe characteristics of planetary gear transmission, the calculation methods of loadcapacity for planetary gear transmission are analyzed, providing theory basis isprovided for the subsequentresearches.2. Under the conditions of satisfying the strength and service life of thetransmission system, pursuing maximum power density, using multiple target design,parameter optimization model of yaw gearbox is established, and its key driveparameters are optimized.3. Correct prediction of service life for the bearings is not only the key ofensuring the normal work for transmission system, but also has important influenceon its size.Based on ISO281:2007“Rolling bearings-Dynamic load ratings and ratinglife”, calculation methods of life factor and modified life for rolling bearings aredescribed in detail in this paper,and some factors affecting bearing life are analyzed.4. The finite element model of single-arm planet carrier is built; influence ofstructural parameters on strength and stiffness for single-arm planet carrier is analyzed. The general distribution of strength and stiffness along the axial and radial directionfor single-arm planet carrier is given. The stress and deformation of the circular andtriangle structures for single-arm planet carrier are analyzed and compared.5. The finite element model of double-arms planet carrier is established;influence of the connecting slab thickness and input side plate thickness on strengthand stiffness for double-arms planet carrier is analyzed. Aspects of strength, stiffnessand mass for single-arm and double-arms planet carrier in the same size are analyzedand compared.6. The finite element model of the housing assembly-body for multistageplanetary gearbox is built, with the analysis platform of SolidWorks Simulation, thestatic and dynamic characteristics such as stress, deformation and modality of thehousing are studied, providing the basis for the lightweight design of the housing.