全程转速下浮动支撑湿式离合器带排转矩计算模型与验证

Modeling and Experimental Validation of Drag Torque of Wet Multi-disk Clutch with Spline Connected Restriction in Full Speed Range

基于摩擦元件偏置现象及高转速差下间隙收缩现象,运用陀螺效应原理建立了摩擦元件低转速差下偏置状态分析模型。针对摩擦副间油膜的高速负压现象,建立了高转速差下摩擦副间隙负压收缩模型,分析了从低速差到高速差全程变化过程下的摩擦副间隙动态变化规律。提出考虑摩擦副间隙动态变化影响的带排转矩改进模型,进行了仿真分析,并搭建了带排转矩试验平台。研究结果表明:润滑条件一定时,湿式多片离合器带排转矩随转速差增大呈先增大、后减小、再增大的变化趋势;摩擦副偏置现象在低转速差(0~1 000 r/min)段对带排转矩影响较大,而间隙收缩现象在中转速差和高转速差(大于1 000 r/min)段时为影响带排转矩的主要因素;通过与试验结果对比发现摩擦副间隙动态变化影响的改进模型平均相对误差在中转速差和高转速差(大于1 000 r/min)段时为6.34%,显著提高了对湿式多片离合器带排转矩值估算的准确度。

A theoretical model is established for the analysis of offset state of friction elements under the condition of low speed difference based on the gyro effect.As for the gap shrinkage under the condition of high speed difference,a negative pressure contraction model for friction pairs is built by analyzing the oil film and the pressure on friction plates.The dynamic change of gap between the friction pairs in the whole variation range of the relative speed is then investigated.Finally,an improved model,considering the influence of dynamic change of gap between the friction pairs,is proposed to study the drag torque.The simulated and test results indicate that,under the condition of the same lubrication,the drag torque of the wet multi-plate clutch increases first and then decreases and finally increases with the rise of the rotational speed difference.The main factors influencing the drag torque are the offset of friction plate under the condition of the low speed difference(0-1 000 r/min),and the gap shrinkages under the condition of the middle and high speed differences(>1 000 r/min).Through the comparison of test results and the simulated results obtained from the improved model,the average relative error is only 6.34%under the condition of medium and high speed differences(>1 000 r/min),which can greatly improve the estimation accuracy of drag torque of wet multi-plate clutch.