滑动轴承支承人字齿轮行星传动固有特性分析

Natural Characteristics Analysis on Herringbone Planetary Gear Trains with Slide Bearing Support

考虑滑动轴承支承刚度不对称和耦合特性,建立计入内齿轮轴向振动的人字齿轮行星传动动力学模型。利用4个刚度系数描述行星轮滑动轴承支承油膜刚度。分析系统的自由振动特性,发现系统存在5种振动模式:中心轮扭转—轴向振动模式、内齿轮扭转—轴向振动模式、中心轮横向振动模式、内齿轮横向振动模式和行星轮振动模式。根据每种振动模式的振型特征,推导出5种模式固有特性的低阶计算公式。系统固有频率的分布范围比直齿、斜齿行星传动系统小。结果表明,油膜刚度不对称不会对振型特征产生影响,但是刚度耦合不对称时中心轮横向振动模式会发现显著变化:对应的二重固有频率变成两个不同的单重频率,振型呈现新特征。

A dynamic model of herringbone planetary gear trains is developed considering the axial vibration of two rings and asymmetry and interaction of oil film stiffness.Four stiffness coefficients are used to describe the oil film stiffness of slide bearings for planets＇ support.The free vibration characteristic is analyzed and the vibration modes are divided into five groups： rotational-axial vibration mode of center gears,rotational-axial vibration mode of rings,translational vibration mode of center gears,translational vibration mode of rings and planets vibration mode.For each class of mode,the reduced-order inherent characteristics formulas are derived according to the properties of each vibration mode.The distribution range of natural frequencies is smaller than those of spur and helical planetary gear trains.It reveals that although the asymmetry of oil film stiffness has little influence on the vibration modes properties,the significant changes of translational vibration mode of center gears will happen if there is asymmetry interaction of oil film stiffness： the corresponding twofold natural frequencies will turn into two different frequencies and new characteristics of vibration mode will appear.