Simulation Analysis Of Idling Loss-Engagement Process For Wet Friction Clutch And Oil Circuit Structure Optimization

The wet friction clutch,as an important component of the transmission mechanism of mechanical equipment,the mechanical properties and hydrodynamic characteristics of which have attracted much attention.The active and driven disks of wet friction clutch will produce oil film bearing capacity and friction torque due to the viscous action of lubricating oil before contacting.The increase of working oil temperature will lead to the decrease of lubricating oil viscosity,and the change of viscosity can affect the engagement property in turn.It can be seen that this is a transient dynamic process.Therefore,it is of certain theoretical significance and engineering value to improve the comprehensive performance of wet friction clutch by the simulation analysis of the idling loss-engagement process and the optimization of the oil circuit structure.In this paper,the following four aspects of wet friction clutch are studied,the influence factor analysis of wet friction clutch engagement process,the transient simulation analysis of heat-flow coupling in idling loss stage,the transient simulation analysis of fluid-solid-heat coupling in the sliding friction extrusion stage,and the oil circuit structure optimization of wet friction clutch.The main research work of the thesis is as follows:(1)The several main influencing factors in the process of wet friction clutch engagement are studied,the paper emphatically analyses the friction mechanism of clutch plate pair and the viscous temperature characteristic of lubricating oil,deduces the mathematical equations of the friction coefficient of clutch plate pair and the viscosity of lubricating oil.By means of MATLAB/Simulink software,the numerical simulation curve of the friction coefficient and the viscosity-temperature characteristic are obtained respectively.(2)For the clutch Idling loss stage,the dynamic model of the friction plate pair is established,the mathematical expression of the towing torque is deduced,and with the help of MATLAB/Simulink software,the towing torque in the starting process of the clutch active shaft is analyzed and calculated,and the results are in good agreement with the heat flow coupled transient simulation.Then the influence of the compound oil groove on the heat flow field of clutch is further analyzed.(3)For in the sliding friction extrusion stage of wet friction clutch engagement process,the transient simulation of the fluid-solid-heat coupling is carried out with the help of ANSYS Workbench and Fluent software,and the changing regularity of clutch dynamic engagement characteristic is obtained.The analytic value of the oil film bearing capacity is calculated and compared with the simulation results,the two are in good agreement.The influence of the rotational speed of the active shaft on the engagement characteristics of the clutch is studied.(4)The parametric finite element model of the clutch oil circuit structure was established with the diameter of outlet pipes as variables,and the dynamic simulation of the clutch was carried out by the software of ANSYS Workbench and CFX,single factor simulation tests were adopted to determine the minimum axial displacement of clutch plates as the target variable.The optimum oil structure is obtained based on response surface method,and the optimization effect is good.