Analysis of the Various Factors Affecting Drag Torque in Multiple-Plate Wet Clutches

Experiments were conducted to study the effects of design factors of clutch packs on drag torque. From the test results, the design factors with a large effect were facing area and wave height. At high rotational speeds, automatic transmission fluid (ATF) flow rates and the number of grooves also had a significant effect. At low rotational speeds, since drag torque increased linearly with increasing speed, the results were compared to calculated values using theoretical equations based on Newton's law of viscosity. Furthermore, it was confirmed through visualization experiments of ATF flow on the rotating facing surface that the ATF completely covered the surface at low rotational speeds and that air mixed with the ATF at high rotational speeds.