The influence of inertia resistance on the drag torque in the wet multi-disk clutch with splined connected restriction

A theoretical model of friction plate is established by using Resal theorem, and the inertia resistance of the friction plate is obtained from this theoretical model. Focusing on the bias phenomenon in friction pairs, a new model is investigated for analyzing the bias state under low speed difference considering about the gyro effect. As for the gap shrinkage under high speed difference, the negative pressure contraction model for the friction pairs is built by analyzing the oil film and the pressure between plates. Based on that, the influences of the inertia resistance of the friction plates for these two models are also discussed. Afterwards the gap dynamic change between friction pairs is investigated in the whole variation range of the relative speed. Finally, an improved model, considering the influence of the gap dynamic change between friction pairs, is proposed to simulate the drag torque. The results obtained from the simulation and test data indicate that, under the same lubrication condition, the drag torque in the wet multi-disk clutch increases at first and then decreases and finally increases with the rise of the rotational speed difference. Furthermore, the main factors influencing the drag torque are the bias of plates in the low speed difference (0∼1000r/min) and the gap shrinkage in the medium and high speed difference (>1000r/min) respectively. From the comparison between test data and the simulation results obtained from the improved model, the average relative error is only 6.34% at medium and high speed difference (>1000r/min), which can greatly improve the accuracy for the estimation of the drag torque in wet multi-disk clutch.