Research On The Thermodynamic Characteristics Of The Friction Pair During The Mixed Friction Process Of Hydro-viscous Clutch

Hydro-viscous clutch relies on the viscous fluid shear force between the friction pair to achieve the power transmission and the speed regulation of the load.It is widely used in the soft start and running speed regulation of the fans,water pumps and other devices,showing remarkable energy-saving advantages.Thermal failure of the friction pairs is the main cause of the failure of the hydro-viscous clutch.In order to understand the thermal deformation mechanism,the thermodynamic properties of hydro-viscous clutch friction pair under the mixed friction condition was studied by element method and experiment method.The results of the study have some engineering significance for the prediction of the temperature field and stress field during the operation process of the hydro-viscous clutch and the design of the friction pairs.The main contents are as follows:(1)The three-dimensional finite element model of friction pair was established.The initial conditions and boundary conditions of the thermo-mechanical coupling finite element analysis of the friction pair under the mixed friction condition were determined according to the actual working conditions.Introduced indirect coupling method to complete the coupling analysis between the temperature field and the stress field of the friction pair,the distribution of temperature field and thermal stress field and the deformation law of friction pair were obtained.(2)The influence of the friction sub-piece material,the thickness of the separator disks and the friction lining,and the groove width and depth on the temperature field of the friction pair were comparatively analyzed under the same conditions.The results show that the friction disk temperature of the paper-based material is much lower than that of the copper-based material,the friction disk temperature decreases with the increase of the groove width,and first lower and then increased with the increase of the groove depth.(3)Designed the specific experimental scheme,experimental study were carried out to investigate the effect of relative speed between the active disk and passive disk,the pressure and flow rate of the working medium oil on the temperature field of the friction disk.The test results show that the relative speed between theactive disk and passive disk and the working medium oil flow have great effect on the temperature of the friction disk.The temperature of the friction disk increases with the increase of the relative speed between the active disk and passive disk rapidly,and decreases with the increase of the flow rate of the working medium.The influence of the pressure of the working medium oil on the temperature field of the friction disk is not obvious.