Thermo Mechanical Coupling Analysis And Structure Optimization Of Friction Pairs Of Liquid Viscous Speed Regulating Clutch

Hydro-viscous clutch has high transmission efficiency and can realize stepless speed regulation.It is widely used in the field of soft start and speed regulation of large machinery,such as fan and pump.The key component is the friction pairs,during in regulating the speed,the friction pairs are under complex conditions,the asperity contact friction will lead to temperature rise and friction structure deformation,reducing the transmission efficiency and service life of the clutch,therefore,the research on the friction pairs of HVD clutch friction is important,the main research contents are as follows:(1)The three-dimensional heat conduction model of the friction pair was established,the calculation model of the heat flux density and the convective heat transfer coefficient were explored.The theoretical solution process of the temperature field of the friction pair was studied and the distribution of the stress distribution of the friction pair was obtained by the coupling theory.(2)Comparative analysis the influence to temperature field and stress field of the friction pair under different material combinations and friction pairs’ size,the results showed that the change of friction linings,substrate and dual plate material has a greater impact on the friction temperature field,finally,the material combination of the following research was determined: the dual plate material is 65 Mn,the friction lining material is copper based powder metallurgy material,the friction substrate material is 45 steel.The temperature rise and deformation of the friction pair can be improved by increasing the thickness of the friction lining and increasing the ratio of the inner and outer diameters.(3)Through single factor analysis about groove depth、number and angle of the friction plates,best response range was determined.Using Box-Behnken module of Design-Expert software to do response surface analysis,the results show that those three factors have a great impact on the temperature and torque,and B(angle)has the most great impact.The optimal parameter combination of grooves was obtained: the A(number)is 20,the B(angle)is 5.55 degrees,and the C(depth)is 0.5mm(4)The torque was obtained by experimental method,and it was compared with the numerical value of the simulation torque.The results agree well with each other,which verifies the reliability of the simulation data,and studied the oil film temperature rule under different boundary conditions,research shows that the friction speed difference has a bigger influence on the oil film temperature,high speed difference makes the oil film shear product more heating,which makes oil film temperature rise,changing the inlet flow and the inlet pressure do a small impact,when increasing the inlet flow,the oil film temperature will decrease.