The Research On Transmission Performance And Control Methods Of Transfer Case In The Heat Load Environment

With the good cross country of the four-wheel drive vehicle,the four-drive vehicle chassis transmission system has become a research hotspot and frontier subject in recent period.The key to achieve dynamic distribution as a four-wheel drive vehicle,multi-plate clutch assembly parts,is currently the most core content.Its design performance will directly affect the four-wheel drive vehicle drive system performance.The multi-plate clutch is the key component of the power distribution of the four-wheel drive vehicle.The relevant research work is rare at present.For multi-plate clutch friction characteristics and control method of this basic problem,the project is based on the analysis of contact multi-plate clutch friction characteristic,getting the line contact friction and circular motion principle of friction and multi-plate clutch is derived with mathematical model of the viscous torque,the viscous torque and rough friction torque and total torque calculation model of the friction plate and the dual steel disc are established.Considering the influence of the heat load of multi-plate clutch,based on electromagnetism and system dynamics of electromagnetic multi-plate clutch mechanical model,using the neural network PID optimized torque distribution control system,do research on different road surface,the change of current under different working condition of the speed and steering torque distribution of electromagnetic multi-plate clutch in speed difference,the speed of the vehicle,the influence law of side-slip Angle and yawing angular velocity.Based on the mechanical structure and control theory of multi-plate clutch at home and abroad on the basis of related research,the article uses the means of the theoretical study and simulation analysis and experiment validation to research the combining of the multi-plate clutch transmission mechanism and the control strategy.The main research work and relevant results achieved are as follows:(1)Completing the study on the principle of contact friction and circular motion friction of multi-plate clutch lines.Firstly,a detailed theoretical formula is derived for the contact of single asperity revisited and multi-asperity surfaces.The relationship between the thickness of oil film and centrifugal force is obtained by using the motion equation and continuity equation of viscous fluid.Finally,the equivalent outer diameter is introduced into the multi-plate clutch mathematical model,which provides the accurate parameters for the mechanism analysis of the multi-plate clutch.(2)The mathematic model and analysis of multi-plate clutch are established.Firstly,we have established multi-plate clutch engaging process of the oil film dynamic pressure,static pressure,centrifugal and total capacity model of oil film bearing capacity,and the multi-plate clutch can transfer the asperity torque and the total torque model.Then analyse different oil groove width,different number of oil tank,different initial oil film thickness,different number of the friction plate,different pressure and different roughness of the friction plate,the permeability of different friction plate and the viscosity of viscous torque of different lubricating oil,asperity torque and total torque and the influence of oil film thickness changes,etc.(3)Research on the dynamic transmission characteristics of transfer case under thermal load characteristics.Under the condition of using the basic principle of heat transfer,heat load on the friction coefficient of friction plate and the influence of the lubricating oil viscosity,based on heat load are studied under different conditions on the viscous torque,asperity torque and the influence law of the change of the total torque.In order to verify the correctness of the transfer case mathematical model,a transfer case transmission system test bench was designed and verified with the simulation data.(4)Study on the parameter characteristics of the electromagnetic transfer case.Analyses the working principle of electromagnetic transfer case and related characteristics through the electromagnetic principle and implement the work characteristics of electromagnetic clutch friction plate of theoretical derivation,getting complete calculation formula.Based on the previous friction plate clutch dynamic transfer equation,a complete power transfer equation of electromagnetic transfer case is established.(5)Research on the control system of electromagnetic transfer case torque based on intelligent PID control.With the half vehicle model of two degrees of freedom linear to be the reference object,using the neural network PID optimized torque distribution control system,research on different road surface,the change of current under different working condition of the speed and steering torque distribution of electromagnetic transfer case in speed difference,the speed of the vehicle,the influence law of side-slip Angle and yawing angular velocity..