Influences of surface grooves on friction plate on drag torque of wet clutch

According to mass flow balance on disengaged wet clutches, the flow equation and oil film equivalent shrinking radius of radial grooved and flat friction plate were deduced. Based on experimental data of drag torque, the flow calculation and drag torque model of double arc grooved friction plate were obtained, considering the flow correction factor. Results show that when relative sliding velocity on average radius is less than 8.83 m/s, drag torque of double arc grooved friction plate is close to that of radial grooved friction plate, when relative sliding velocity is more than 9.39m/s, drag torque of double arc grooved friction plate can be estimated with flat friction plate. Also, increasing groove width or groove depth can decrease drag torque effectively.