考虑ARMA风速模型半直驱风电行星齿轮传动系统动力学分析

针对半直驱风电行星齿轮系统的变速变载的特点,考虑风速变化引起的外部载荷激励,采用自回归-滑动平均(ARMA)方法建立模拟风速模型,在考虑时变啮合刚度、啮合阻尼等因素的基础上,采用集中参数法建立了行星齿轮传动系统平移-扭转耦合动力学模型。并采用四阶龙格-库塔法,求解1.5 MW半直驱风力发电行星齿轮传动系统的动态响应。

复合故障状态下行星齿轮-转子耦合系统振动响应特性研究

目前,国内外学者对齿轮-转子耦合系统的动力学特性进行了研究,但是上述研究均没有考虑行星齿轮-转子复合故障状态。为此,以单级行星齿轮箱为例,通过构建含转子偏心和齿根裂纹故障的行星齿轮-转子耦合系统动力学模型,对复合故障状态下的行星齿轮-转子耦合系统振动响应特性进行了仿真分析和实验研究。首先,采用了集中参数法和Timoshenko梁理论,考虑了时变啮合刚度、支撑刚度、阻尼、陀螺效应、传动轴柔性等因素,建立了含转轴偏心-齿根裂纹复合故障的行星齿轮-转子耦合系统动力学模型;然后,采用了时间历程、频谱、轴心轨迹及相轨迹等方法,并根据其数值分析了不同故障对系统动态特性的影响,研究了偏心状态下裂纹扩展对系统振动响应特性的影响;最后,采用不同裂纹故障测试实验,验证了模型的准确性。研究结果表明:转轴偏心对啮合振动的影响显著,在行星轮系故障特性的分析中不可忽视;偏心-裂纹耦合影响下,系统振动响应由不平衡振动、正常啮合振动、故障冲击振动多源耦合而成,频谱中出现了转频f_( r)、啮合谐波kf _(m)以及复杂边带成分kf _(m)±f _(r)、kf _(m)±f _(r)±nf _(sc),并且随着裂纹程度的加大,调制现象更加明显。该研究结果可以为行星齿轮-转子系统复合故障诊断提供一定的理论依据。

Analysis of lubrication performance for internal meshing gear pair considering vibration

The thermal elasto-hydrodynamic lubrication characteristics of the internal meshing gears in a planetary gear train under vibrations were examined considering the influence of the modification coefficient and time-varying meshing stiffness.Based on dynamic theory of the gear system,a dynamic model of the planetary gear train was established.The lubrication performances of modified gear systems under vibrations and static loads were analyzed.Compared with other transmission types,the best lubrication effect could be produced by the positive transmission.A thicker lubricating oil film could be formed,and the friction coefficient and oil film flash temperature are the smallest.Increasing modification coefficient improves the lubrication performance continuously but intensifies the engage-in and tooth-change impact.For the planetary and inner gears,the increase in the modification coefficient also leads a decrease in the oil film stiffness.