换挡离合器摩擦元件周向间歇接触温度场研究

With consideration of the effects of temperature and sliding velocity on friction coefficient, an iterative model for calculating the temperature field of circumferential intermittent contact between friction elements of shifting clutch under macro-dimension is established to study the influence of intermittent contact, corresponding to the number of spline teeth, on temperature field and friction coefficient, and the model is validated by friction coefficient measuring experiments. The results show that intermittent contact may result in high temperature zones appear on the surface of friction disks, and the distribution of the high temperature regions corresponds to the number of spline teeth. The highest temperature and average temperature of friction disks lower with the increase of the number of spline teeth, and the temperature rise in friction disks exhibits nonlinear correlation with the number of spline teeth and sliding time. Under the same sliding condition, with the sliding time extending, the friction coefficients, corresponding to different number of spline teeth gradually increases to the same maximum value, and before the friction coefficient reaches the maximum value, the friction coefficient corresponding to fewer spline teeth is larger. Under shifting condition, the friction disks with less spline teeth quicker enter the state of dry friction and reach larger friction coefficient in shorter period of time. Under the long time sliding conditions such as when the vehicle creeps with foot on clutch, the friction disks with more spline teeth have less local temperature rise with better thermal safety.