Research On Thermal Mechanical Coupling And Thermal Management Of Wet Clutch With Electronic Limited Slip Differential

Electronic Limited Slip Differential(ELSD),as the power distribution unit on the driving axle of the car,plays an important role in driving performance,operational stability and driving safety of the car.Wet clutch is widely used in automotive transmission system because of its large transmission torque and good heat dissipation performance.It is also an indispensable part of electronic limited slip differential.In this paper,the thermal mechanical coupling analysis of wet clutch in electronic limited slip differential is established,and the comparative analysis of different structural parameters and operation parameters of wet clutch is set up,which provides a reference for the structural optimization of wet clutch and the development of thermal management system.The main contents of this paper are as follows:(1)Firstly,the structure and working mode of the electronic limited slip differential are introduced.The working principle,friction characteristics and engagement process of the wet clutch of the electronic limited slip differential are mainly introduced and analyzed.The lubrication mechanism of the friction pair is elaborated in detail.Mathematical models of automobile components related to electronic limited slip differential are analyzed.Engine model,power transfer model of wet clutch and tire model are constructed.(2)The basic theory of heat transfer in the working process of wet clutch is emphatically analyzed.The three-dimensional model of friction pair of wet clutch is constructed by using ANSYS finite element software,and according to the classical thermodynamic theory,the differential equation of heat conduction is deduced,the distribution function of heat flux and the loading model of convective heat transfer function are established.Based on the setting of thermal boundary conditions and mechanical external force boundary conditions,a thermal mechanical coupling analysis model of wet clutch is established.(3)The thermal mechanical coupling of friction pair of wet clutch is analyzed in detail,and the distributions of temperature field and stress field of friction disc and dual steel disc during wet clutch engagement are analyzed.The temperature field and stress field of the dual steel sheet of the friction pair of wet clutch with different structures are analyzed,and the variation law of temperature and stress under different radius difference between inside and outside is obtained.At the same time,the friction pairs of wet clutch under different working parameters are analyzed,and the relationship curves between temperature change and working pressure,engagement time and speed difference were obtained.(4)The thermal management system is summarized,and the idea of temperature control for wet clutch by building thermal management system is put forward.Based on the data obtained from ANSYS finite element analysis,the temperature prediction model of wet clutch is established by using MATLAB calculation and analysis,and the thermal management model of wet clutch is established by Simulink/AMESim simulation.The feasibility of applying heat management system to wet clutch is preliminarily verified.