湿式离合器接合过程摩擦振颤的影响因素

Influence Factors of Friction-Induced Oscillation During Wet Clutch Engagement

针对湿式离合器在接合过程中的摩擦振颤问题,通过建立四自由度动力传动系统动力学模型及推导由摩擦效应引起的综合导入阻尼,基于特征值分析,获得系统的稳定性条件.通过Matlab/Simulink仿真研究了摩擦因数、控制油压历程、转动惯量和传动轴刚度等对离合器摩擦振颤的影响.结果表明:由摩擦因数和控制油压历程决定的综合导入阻尼为负时,系统失去稳定性.同时,控制油压先快后慢的上升方式、增大离合器从动部分转动惯量及增加输出轴刚度均可不同程度地抑制摩擦振颤.

A simplified 4 degree-of-freedom （DOF） power-train dynamic model with an integrated damping induced by the friction effect of a wet clutch was developed to investigate the friction- induced oscillation （judder） during engagement, which may worsen the clutch engagement quality and result in the clutch failure. The stability criteria were obtained based on the eigenvalue analysis method. The numerical simulation in Matlab/Simulink was performed to evaluate the influence of different parameters such as the coefficient of friction, the variation process of control oil pressure, the moment of inertia of the clutch and the stiffness of drive shafts on the clutch judder. The results indicate that the system instability occurs when the integrated damping, which is determined by the coefficient of friction and the oil pressure, is negative. The results further show the clutch judder attenuates with the increase of the moment of inertia of the clutch driven component and the rise of the stiffness of the transmission output shaft. When the oil pressure rises rapidly at the early stage then followed by a slow rate, the amplitude of the friction-induced oscillation decreases.