风电机组变桨轴承载荷分布研究
Load Distribution Research on Pitch Bearing of Wind Turbine Generators
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摘要: 变桨轴承是风电机组传动与控制系统的关键部件,安装形式特殊且承受复杂的轴向、径向力和倾覆力矩等交变载荷。文中基于经典的赫兹弹性接触理论,建立了刚性套圈承受多向力和倾覆力矩的双排四点接触球变桨轴承的力学模型。在此基础上,应用弹性等理论研究套圈变形对轴承载荷分布的影响,推导轴承外载荷和滚动体接触力等载荷作用下转盘轴承内、外套圈的弯曲变形方程,联立非线性超越方程组给出了四点接触球转盘轴承分布载荷的求解方法。以某型号变桨轴承为例,分别采用刚性和柔性套圈2种模型对轴承载荷分布进行了计算和对比分析。结果表明2种模型下轴承载荷分布有显著区别,柔性套圈模型下的承载区间减小,载荷分布更加均匀,滚动体的承载能力有很大的提升。相关力学问题的研究可为变桨轴承结构设计提供必要的理论依据。Abstract: Pitch bearing is a key component of the drive and control system of a wind turbine, which withstands complex alternating load of axial force, radial forces and overturning moment with special installation method.According to the Hertz elastic contact theory, a mechanical model of double row four point contact ball rigid ring bearing was established. Based on the elasticity theory, the influence of ferrule deformation on load distribution was researched. Then the equations about the bearing internal and outer ring bending deformation under the rolling contact load and the bearing load were deduced, and a solving method using nonlinear transcendental equations to analysis four-point contact ball bearing was obtained. Taking a typical pitch bearing as a case,the load distribution was calculated and analyzed by using the rigid and flexible ring model, respectively. The results show that the load distribution calculated based on these two models is markedly different. The load distribution is more evenly with decrease in the intervals of the distribution using the flexible ring model. The rolling elements carrying capacity has greatly improved. These results provide reliable theoretic base for pitch bearing design.