Research On The Friction Torque Model Of A Dry Clutch

Accurate friction torque is important in improving the control accuracy of clutches,the dynamic performance and economic performance of vehicles.Dry clutch friction torque can be affected by many factors,such as environmental temperature,surface temperature of clutch plates,relative sliding speed between the driving clutch disc and the driven clutch disc,clamping force,diaphragm spring wear,clutch plates wear.So accurate friction torque is hard to get always.The paper tried to get accurate friction torque by the traditional analyzing method and the estimation method.The analyzing method can be divided into four parts.Firstly,analyzing diaphragm spring force transferring characteristic based on the traditional A-L formula,building the clamping force model and doing the bench experiment.Secondly,designing the friction coefficient bench to measure the friction coefficient with sliding speeds,clamping force and surface temperature changing.And establishing the friction coefficient model.Thirdly,building the clutch temperature model by the finite element method.Fourthly,combining the clamping force model,the friction coefficient model and the temperature model,building the clutch friction torque model and doing the bench experiment.The estimation method means estimating the clutch friction torque indirectly by some signals coming from vehicles.The paper estimated the clutch friction torque by the engine speed,the nominal engine torque and the nominal clamping force without adding extra sensors.The paper established the clutch friction torque estimation model by the gradient projection method and the self-adaption method,and the estimation model are verified by the bench experiments.