混合润滑下短齿啮合对行星齿轮接触疲劳的影响

Effect of Short Teeth on Contact Fatigue in Planetary Gears under Mixed Lubrication

少齿差行星齿轮为避免齿顶干涉,通常会减小齿高,这可能会导致齿面实际接触宽度小于理论赫兹接触宽度,降低齿面接触强度.鉴于此,为研究少齿差行星传动短齿制对齿轮接触疲劳的影响,综合考虑了轮齿接触宽度、楔形间隙、齿宽有限长和齿面粗糙度等因素,建立少齿差行星齿轮短齿啮合的混合润滑统一方程,求解出啮合齿对间的压力分布、摩擦系数和轮齿接触区次表面应力分布,根据Zaretsky接触疲劳寿命计算模型,对不同工况下不同啮合位置的轮齿接触疲劳寿命进行预测.结果表明:接触宽度在少齿差行星齿轮的疲劳寿命预测中不容忽视,短齿啮合模型下的楔形间隙对啮入和啮出过程的疲劳寿命有不同影响.

Planetary drives with small teeth number （PDSTD） are designed with short tooth depth in order to avoid the interference of addendum, which results in shorter contact width than Hertzian contact width and cause the reduction of contact strength. In order to analyse the effect on contact fatigue of short teeth in PDSTD, the uniform equation of mixed EHL for short teeth in PDSTD was established with factors of contact width, wedge clearance, finite line contact and surface roughness. Then pressure distribution and friction were calculated, as well as the subsurface von Mises stress. According to Zaretsky＇s model, contact fatigue life of meshing tooth in different operating conditions and engaged positions was predicted. The results indicate that contact width cannot be ignored in the prediction of fatigue life in PDSTD, and fatigue life in meshing-in and meshing-out was different due to the wedge clearance.