Nonlinear Dynamic Characteristics of Rub-Impact Process at High Circumferential Velocities in No-Load Multiplate Wet Clutch

Drag torque is common in wet clutches, and the mechanism of drag torque at high circumferential velocities is not yet well understood. In this article, fluid action, rub-impact action, and rotary moments, as well as the coupling motion relationship between the friction plate and steel plate in 3 degrees of freedom, are taken into consideration to establish the fluid–solid coupling dynamic model of the friction pairs. In addition, a theoretical model of the rub-impact drag torque in a multiplate wet clutch is proposed based on the dynamic contact impact theory. Due to the significant influence of the dynamic behaviors of the friction pairs on drag torque, the nonlinear motion characteristics of the friction pairs are analyzed. From an energy balance point of view, the impact mechanism of the friction pairs is revealed. Through this research, it can be found that the motion of the friction pairs becomes unstable and chaotic with an increase in rotating speed, and at approximately 2,300 rpm contact between the friction pairs occurs because a large amount of air enters and the fluid does positive work on the friction pairs.