风力发电机组变桨轴承连接螺栓预紧精度控制方法研究

Research on improving the preload accuracy of bolts connection between pitch bearing and hub of wind turbine

针对变桨轴承连接螺栓因预紧力不足导致疲劳断裂问题,分析造成预紧力不足的拉伸器拉伸回弹现象,通过实验研究影响拉伸器拉伸回弹的因素。分步骤改进拉伸器紧固螺栓的拉伸工艺,实验数据表明,在螺母下增加垫圈、在螺母及螺纹处涂润滑膏、重复预紧以及超张拉都有助于稳定螺栓残余预紧力,减小离散性。研究结果表明,使用改进后的紧固螺栓拉伸工艺,螺栓残余预紧力平均值达到设计目标值的98%,且非常稳定。

Aiming at the problem of fatigue fracture of the pitch bearing connecting bolts due to insufficient pre-tightening force,the tensile"rebound"phenomenon of the tensioner caused by insufficient pre-tightening force is analyzed.This paper studies on the factors that affect the rebound phenomenon through experiments,and improves the operation process of the pre-tightening bolts of stretcher step by step.It shows that adding washer under the nut,and applying lubrication on the nuts and threads,or repeated stretching of the fastening bolts,as well as over tensioning,all help stabilize residual preload and reduce dispersion.The result shows that the average residual preload reaches 98%of the design target by using the improved tightening bolt stretching process,and it is very stable.