考虑支撑结构及螺栓连接的变桨轴承强度分析

Strength Analysis for Pitch Bearing Considered the Support Structure and Bolt Connection

针对MW级风电机组变桨轴承静强度与疲劳强度分析的问题,建立了考虑轴承支撑结构刚度及螺栓连接的"叶片-轴承-轮毂"整体等效有限元模型。变桨轴承等效模型中滚球与滚道接触采用非线性弹簧等效,弹簧刚度利用Herz理论进行计算,并将弹簧节点与滚道曲面采用刚性联接,模拟滚球与滚道的接触边界条件;轴承与叶片、轮毂的螺栓连接采用梁单元进行等效,两端分别与被联接零件刚性联接,模拟轮毂-轴承-叶片螺栓联接接触边界条件;模型中弹簧载荷即为滚球载荷,基于Herz接触理论将得到的滚球载荷转化为接触应力,并可以分析滚球接触角变化与套圈变形及应力。采用此模型并结合ISO标准可以在考虑支撑结构及螺栓连接的基础上有效地分析变桨轴承静强度及疲劳强度,并且减少大规模接触计算,提高了计算效率。

To analyse the static strength and fatigue strength of pitch bearings in the MW wind turbine,we established the integral equivalent finite element model of the＂blade-pitch bearing-hub＂considered the bolt connection and bearing support structure stiffness. We used nonlinear spring to replace the contact of the bearing ball and bearing raceway in the finite element model,got the spring stiffness based on Herz theory. Besides,the spring keypoint and the bearing raceway were rigidly connected in order to simulate the contact between the ball and raceway. We used beam element to replace the bolt connection in the ＂blade-bearing-hub＂finite element model. And the two ends of equivalent bolt was connected with the clamped parts by rigid connection in order to simulate the real bolt contact boundary conditions; in the model,we got the spring load as ball load,and then translated it to the contact stress based on Herz theory. Besides,we could analyse the change of contact angle and bearing ring deformation and stress. This model can be used to calculate the static strength and fatigue strength of pitch bearing considered the bearing support structure stiffness and bolt connection combined with the ISO standard. Besides it reduced the massive contact computation and improved the computational efficiency.