Abstract: The wet clutch has the problem of accelerated failure due to the deterioration of the local lubrication condition, and at present, few scholars have studied the influence of pressure on the local lubrication and friction characteristics of the wet clutch from the local microscopic point of view. For this reason, from the local microscopic point of view, the simulation analysis and experimental test research were carried out on the pressure influence characteristics of the local lubrication and friction of the wet clutch. Firstly, a thermal mixed lubrication model in plane contacts was developed. The load supported by asperity contacts and the hydrodynamic pressure were calculated at the same time. Then, small sample pinondisc tests of wet clutch friction pair were conducted to test the variation law of the local lubrication and friction characteristics under various pressure conditions. Finally, based on the simulation and test, the pressure effects on local pressure distribution, load sharing ratio, actual contact area, local temperature rise and friction coefficient of wet clutch friction pair were analyzed. The results indicate that, as the mean surface pressure increases from 1.4MPa to 4.2MPa, the local lubricant film thickness between the friction pair decreases and more asperity contacts emerge. Therefore, the actual contact area ratio of the friction pair in wet clutch increases rapidly from less than 1% to about 4.5%, and the friction coefficient increases rapidly from about 0.047 to about 0.074. The increasing speed of the friction coefficient is basically the same as that of the actual contact area ratio.
Key words:  mechanical transmission; thermal mixed lubrication model in plane contacts; friction and wear testing machine; pinondisc tests; pressure influence; friction temperature rise