Study On The Multi-field Coupling Dynamic Simulation And Thermal Failure Study Of Wet Clutch

Wet clutch is the core component of the automobile transmission system,which has the advantages of large transmission torque,high transmission efficiency and small shift impact.Wet clutch in the working process through the friction torque to transfer power,the friction vice master and driven end of the relative slip will generate a lot of heat and be absorbed by the friction vice,heat if not taken away by the cooling system in time,will lead to the couple steel plate and friction plate temperature is too high,stress is too large,causing the couple steel plate heat warp deformation,friction plate material abnormal wear and even fall off and other friction vice failure phenomenon,the work performance of the whole car.This has a great impact on the performance of the vehicle.This paper takes the wet clutch friction pair as the research object,and analyzes the fluid oil and gas distribution law,the fluid dynamic heat transfer characteristics and its influencing factors between the friction pair under slippery working conditions,and studies the influence of the fluid dynamic heat transfer characteristics on the thermal failure of the friction pair.The main research contents are as follows.Firstly,the basic theory of heat transfer and the multi-physical field coupling theory involved in the slippage process of wet clutch friction pair are introduced,and the heat generation mechanism and heat transfer mechanism of the friction pair are analyzed theoretically.Secondly,the CFD model of the two-phase flow between the friction subsets is established for the possible two-phase flow phenomenon between the friction subsets,and the distribution law and evolution trend of the two-phase flow field under different relative rotational speeds and different cooling lubricant flow rates are analyzed.This will provide a theoretical basis for the subsequent establishment of a multi-field simulation model of wet clutch friction.Again,a multi-physics coupling simulation model of the wet clutch friction pair is established.The flow characteristics of lubricating fluid,fluid temperature characteristics and surface temperature characteristics of the friction pair are analyzed.The effects of operating conditions and structural parameters on the dynamic heat transfer characteristics of the fluid between the friction subassemblies are studied,and it is found that the tilt angle of the oil groove has a greater influence on the dynamic heat transfer characteristics of the fluid,and the cooling lubricant flow rate,the number of oil grooves,and the depth of the oil groove all have certain effects on the fluid flow rate and fluid temperature.Finally,the influence of operating conditions and structural parameters on the temperature field of the friction substrate is analyzed,and it is found that the tilt angle of the oil tank and the number of oil tanks have a greater influence on the temperature distribution of the hot and hot zones on the surface of the coupling steel sheet,and the depth of the oil tank and the flow rate of cooling lubricant mainly affect the temperature of the surface of the coupling steel sheet.At the same time,the influence of the number of oil grooves and the depth of oil grooves on the stress-strain field of the frictional substrate and the deformation field of the couple steel sheet is discussed.