Analysis Of Mechanical Characteristics And Properties On Part-time 4WD Vehicle Transfer Case

The properties of four-wheel drive vehicle partly depend on the design and manufacturing level of transfer case which is a key component in four-wheel drive vehicle.With the spread of four-wheel drive vehicle,higher requirements are put forward about transfer case like harshness(NVH),reliability,torque distribution,size,weight and others.So it is significant to research on the modal,the fatigue life and the statics analysis of transfer case shell and the mechanical properties of transfer transmission system.This article research on part-time transfer case of four-wheel drive vehicle.Firstly,the finite element model of transfer case’s shell is established on the basis of the theory of computational modal and the platform of ABAQUS,the free modal parameter of transfer case’s shell is acquired.The experiment modal of transfer case’s structure is analyzed on the basis of experiment modal theory and the dynamic signal collection platform of donghua DH5922 dynamic signal collection and analysis system.The accuracy of finite element modal can be confirmed with contrast of the result of experiment modal and computational modal.The maximum error of frequency is5.09%.So the model proved to be right.Secondly,based on the dynamic two drive gear,high speed four-wheel drive gear and the low speed drive gear power transmission path,in romax established dynamic transmission model.Also to dynamic devices supporting the engine output maximum torque,transmission in the first gear and the reverse gear condition as a case study,bisection dynamic transmission mechanism of load spectrum analysis,solve transmission mechanism on the shell of force,divided into dynamic statics analysis provides the load parameters.Finally,the stress values of measuring point are acquired by statics analysis and fatigue analysis of shell structure of transfer case on the sign collection platform of DH3815 N statics stress testing system.The accuracy of finite element modal and Romax transmission modal can be confirmed by contrast of the simulation results in finite element on same condition and the stress values of measuring point with the maximum error of 8.7%.After the accuracy of modal is confirmed,the statics is analyzed on the platform of finite element simulation software ABAQUS which is exerted load in typical working condition.The maximum principal stress of theactuator shell is 180 MPa,which is less than the yield limit of shell material,the maximum deformation amount is 0.050 mm,and the deformation is small.After the analysis results satisfy the demand of strength and stiffness,the safety parameter of shell is analyzed by FE-SAFE fatigue analysis software which analyze the fatigue characteristic of transfer case’s shell.The minimum safety factor of the shell is 1.369,which is more than the allowable safety factor.So the shell is safe.