Abstract Pitch bearings in wind turbines are affected by reciprocating motion due to pitch control. The combination of oscillating operation, high loads, and mixed lubrication often leads to wear. Grease lubricants in wind turbine pitch bearings should be designed to avoid such wear. Due to different available grease lubricants, the anti-wear properties are investigated under downscaled wind turbine pitch bearing conditions. The downscaling is accomplished by load simulation for a pitch bearing and analysis of the pitch movements for a 7.5 MW reference turbine. The operational conditions of the four point contact ball bearing with 5 m outer diameter are scaled to angular contact ball bearings of the size 7208. The investigations are concluded with contact model experiments. Six Industrial grease lubricants for wind turbine pitch bearings are tested that follow very different compositions. The investigations reveal, that none of the tested grease lubricants was able to reduce wear for all tested conditions. After 250 000 cycles certain conditions lead to severe wear. Therefore, the pitch controller should avoid such conditions if possible. Nevertheless, grease lubricants with low base oil viscosities and high bleeding rates are best on average for the tested conditions. Furthermore, the results of the bearing experiments are comparable to the model experiments.

中文翻译：

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风力涡轮机变桨轴承条件下油脂润滑剂的研究

摘要 风力涡轮机中的变桨轴承由于变桨控制而受到往复运动的影响。振荡操作、高负载和混合润滑的组合经常导致磨损。风力涡轮机变桨轴承中的润滑脂应设计为避免这种磨损。由于不同的可用油脂润滑剂，在缩小规模的风力涡轮机变桨轴承条件下研究了抗磨损性能。通过对变桨轴承的负载模拟和对 7.5 MW 参考涡轮机的变桨运动分析来完成缩减。外径为 5 m 的四点接触球轴承的运行条件按比例缩放为 7208 尺寸的角接触球轴承。研究以接触模型实验结束。六种用于风力涡轮机变桨轴承的工业油脂润滑剂经过测试，它们的成分非常不同。调查显示，在所有测试条件下，没有一种测试的油脂润滑剂能够减少磨损。在 250 000 次循环后，某些条件会导致严重磨损。因此，桨距控制器应尽可能避免此类情况。尽管如此，在测试条件下，具有低基础油粘度和高渗出率的油脂润滑剂平均而言是最佳的。此外，轴承实验的结果与模型实验相当。如果可能，桨距控制器应避免这种情况。尽管如此，在测试条件下，具有低基础油粘度和高渗出率的油脂润滑剂平均而言是最佳的。此外，轴承实验的结果与模型实验相当。如果可能，桨距控制器应避免这种情况。尽管如此，在测试条件下，具有低基础油粘度和高渗出率的油脂润滑剂平均而言是最佳的。此外，轴承实验的结果与模型实验相当。