预应力对柔性薄壁轴承疲劳寿命的影响

Influence of Prestress on Fatigue Life of Flexible Thin Wall Bearings

谐波减速器的柔性轴承装配到波发生器椭圆凸轮上时存在较大的预应力和预变形。为研究预应力的影响,利用ANSYS Workbench建立柔性轴承和波发生器凸轮多体接触模型,在实际工作载荷和预应力及预变形作用下,对柔性轴承内外套圈进行分析,得到其变形、应力以及载荷分布规律。分析结果表明,内外圈沟道处的等效应力主要取决于其受到的周向应力;内外圈的最大等效应力和最大径向应力发生在长轴处的球与内外沟道接触的区域。依据L-P理论计算出柔性轴承的疲劳寿命,结果表明,考虑预应力情况下柔性轴承的疲劳寿命降低了30%,研究结果对柔性薄壁轴承的设计及分析提供理论参考和实践指导。

There are large prestress and pre-deformation when the flexible bearing of the harmonic reducer is fitted to the elliptical cam of the wave generator.To study the effect of prestress and pre-deformation,the multi-body contact model were built by ANSYS Workbench, considering the pre-deformation and pre-stress of inner and outer rings of the flexible preassembled bearing.The deformation, stress and load distribution of the flexible inner and outer bearing rings were obtained under practical working condition.The analysis result shows that the equivalent stress of the inner and outer ring is mainly determined by the circumferential stress.The maximum equivalent stress and the maximum radial stress of the inner and outer ring occur in the contact zone between the ball and the inner and outer roiling track at the major axis.According to L-P theory,the fatigue life of flexible bearing was calculated. It is shown that the fatigue life of flexible bearing is reduced by 30% in the case of prestress.The research results provide the theoretical reference and guidance for the design and prediction the fatigue life of flexible bearing.