Transient Thermal Behavior of Dry Clutch under Non-Uniform Pressure Condition

Accuracy of heat flux models is critical to clutch design in case of excessive temperatures due to large amounts of friction heat generated in the narrow space. Pressure distribution on the clutch friction interface is an important factor affecting heat flux distribution, thus affecting temperature distribution. In this paper, an experiment is conducted to obtain the pressure distribution for one typical dry clutch equipped with a set of diaphragm spring. Considering that the frictional interface is in contact, this study makes use of pressure sensitive film and acquires data based on image processing techniques. Then a polynomial mathematical model with dimensionless parameters is developed to fit the pressure distribution on the friction disc. After that, the proposed pressure model is applied to a thermal model based on finite element method. In addition, two conventional thermal models (i.e., uniform heat flux model and uniform pressure model), are implemented for comparison. Finally, a dynamometer test is carried out to verify the proposed pressure model. The simulation results from the proposed pressure model and other two models are provided with temperature profiles along with time and radius. The results from the non-uniform pressure model agrees the experimental results better than those from the two conventional models. Therefore, the proposed non-uniform pressure model could provide a more accurate temperature prediction.