Study On The Analysis Method Of Thermal Deformation And Stress Of Clutch Pressure Plate

Clutch is an important part in a vehicle with manual transmission. Its main function is to transport and cut off the power an engine support.In this progress, friction plate will engage with flywheel. And the clutch pressure plate controls clutch plate engaged and disengaged, the clutch plate with flywheel and they will experience contact, slippery ground, and the process running the same speed.In the event of slipping stage, friction clutch plate and flywheel will generate a lot of heat due to the friction. As the clutch airtight structure, the heat will be transmitted to the clutch pressure plate, the heat caused by the temperature rise will lead to the thermal deformation of the clutch pressure plate and the deformation of the plate will produce heat stress. If pressure plate is not designed in an unreasonable way, the heat stress will lead to rupture of the phenomenon appeared in the clutch pressure plate during work.The paper presents an analysis model and method for analyzing thermal deformation and thermal stress of vehicles clutch pressure plate to solve fracture problem of the plate.A nonlinear mathematical model considering axial characters of cushioning plate and friction coefficient changes along with rotate speed is established. The model is used for analyzing thermal field of the pressure plate during engaging. An experiment is carried to measure the thermal field on plate. The model is validated by comparing the calculated and experiment result.Then using the established model, the thermal stress of the pressure plate is calculated when the vehicle runs in full load and hill start conditions. The calculation result shows that the position of maximum thermal stress on pressure plate in CAE analysis is coincidence with fracture position in practical. The position is the gap on pressure plate outer edge.The thermal stress of the pressure plate is then estimated when gap radius, pressure plate thickness, materials convective heat transfer coefficient and specific heat capacity are changed. The result shows that if gap radius is increase, stress on pressure plate down edge will decrease and when pressure plate thickness is increase, stress on pressure plate up edge will decrease. When materials convective heat transfer coefficient and specific heat capacity increase, stress on pressure plate edge will decrease. Based on the results, the proposal for reducing the stress of the pressure plate is proposed, and the experiment to test if the clutch pressure plate is failure when the vehicle runs in generic case. In the process of the experiment, fracture of pressure plate did not happen again. It is demonstrated that the established model is correct. The developed model and analytical procedure proposed in this paper is instructive for the design and development of clutch.