输入转速波动下斜撑离合器的动态接合特性

Dynamic engagement characteristics of sprag clutch with fluctuation of input speed

采用有限元方法建立PCE型斜撑离合器动力学模型,分析楔块与内外环Mises接触应力、内外环转速跟随性和扭矩传递等特性,得到输入转速随机波动对PCE型斜撑离合器动态接合特性的影响规律。研究结果表明:斜撑离合器楔块的接触应力约为内外环接触应力的1.6倍,输入转速波动8%导致的接触应力波动最大,其标准差达到5%转速波动时的1.5倍;输出转速的跟随误差率大于输入转速波动率;输入转速波动导致的离合器传递扭矩平均波动率为转速波动的5.5倍左右,8%和10%转速波动导致的扭矩波动达到近50%,极大地影响了扭矩传递的稳定性,故输入转速波动应控制在5%以内。

The dynamic model of PCE type sprag clutch was established by using finite element method.The Mises contact stress between wedge and inner/outer ring and the characteristics of inner/outer ring speed following and torque transfer were analyzed.The effects of dynamic engagement characteristic of the PCE type sprag clutch with the input speed random fluctuation were obtained.The results show that the contact stress of wedge of sprag clutch is about 1.6 times the value of the inner and outer ring.The maximum fluctuation of contact stress is caused by 8% fluctuation of input speed,and its standard deviation is 1.5 times of that of 5% speed fluctuation.The following error rate of the output speed is greater than the fluctuation rate of the input speed.The average fluctuation rate of the clutch transfer torque caused by the fluctuation of the input speed is about 5.5 times of the fluctuation of the input speed.The torque fluctuation due to 8% and 10% rotational speed fluctuation reaches nearly 50%,greatly affecting the stability of torque transfer.So, the input speed fluctuation should be controlled within 5%.