Dynamic Analysis And Optimization For Helical Gear Limited Slip Differential

In many parts of the vehicle,differential is an important power transmission part of drive axle.The differential is divided into ordinary differential and limited slip differential,the limited slip differential effectively solves the problem that ordinary differential can not distribute dynamically torque,improves the travellability.At present,the research of the limited slip differential is mainly focused on the analysis of structure?transmission principle and performance,there are relatively few studies on kinematics and dynamics analysis and simulation.Therefore,the simulation and analysis of kinematics and dynamics of limited slip differential is very important for enriching its research.The differential shell is an important part of the limited slip differential,which occupies the most quality.The differential shell is subjected to the external load continuously in the operation of the vehicle,the operating environment is complex.This is the problem that still needs to be solved in the design of the limited slip differential,on the premise that the size of the shell is reasonable,how to reduce the mass of the shell under the condition of satisfying the static(strength,stiffness)and dynamic(modal)of the shell,so as to realize the light quantization of the limited slip differential.The research on the lightweight of the limited slip differential shell is of great significance to reduce the manufacturing cost and realize the lightweight vehicle.The helical gear limited slip differential is analyzed in this paper,after reading a large number of references,by using the dynamics simulation analysis,FEM and topology optimization method to study.The main contents are as follows:(1)The research status and development trend of the limited slip differential are discussed in detail,the structural characteristics,advantages and disadvantages of different limited slip differentials are compared and analyzed.(2)The parameterized model of helical limited slip differential is built by using CATIA three-dimensional modeling software.The design of differential shell is analyzed.Under different working conditions,the system analysis and theoretical deduction of the motion form,output torque change and internal gear meshing force of the helical gear limited slip differential are made.It provides theoretical support for simulation analysis of multi-body dynamics and FEM simulation,and provides guidance for structural optimization of differential shell.(3)Based on the theory of multi-body dynamics,the virtual prototyping model is created by using ADAMS,dynamic simulation of multi-rigid body for helical gear of limited slip differential is conducted,which simulates and analyses with two different typical work conditions,including good pavement and double tire-road friction coefficients,the torque curve,the force and angular velocity curves of helical gear of limited slip differential are acquired,the correctness of model and the effectiveness of simulation method are verified,the multi-condition simulation results show that helical gear of limited slip differential can achieve limited and differential effectively.(4)Based on modal theory,finite element modal analysis based on NASTRAN for helical gear of limited slip differential shell,the vibration frequencies and modes of the first 6-order non-rigid bodies of the shell are obtained.The free modal test platform is built and the vibration frequency of the shell is obtained by testing.The vibration frequency of shell is compared by simulation and experiment,the maximum error is about 2.66%,which verifying the accuracy of the differential case model.Based on the modal vibration frequency data,the correlation excitation frequency is analyzed,and the shell has no resonance phenomenon.(5)Based on the method of finite element analysis,using HyperWorks series software,to carried out the finite element analysis of helical gear of limited slip differential shell,contours of stress and strain are obtained on under extreme conditions,after analysis,the whole structure of shell satisfies the requirement of statics,but there is a phenomenon that the local stress value is far less than the yield strength of the shell and the material utilization is low.To solve this problem,a topological optimization method is adopted to improve the design of the local structure of the shell,then the modal and static mechanics analysis of the optimized shell model is carried out,the rationality of the shell model after topological optimization is validated effectively,the further lightweight of the shell is realized.