Dynamic Characteristics Analysis And Dynamic Response Optimization Of Vehicle Wheel-side Reducer Coupling System

The wheel-side reducer which is fixed in the large and heavy vehicle’s wheel hub isthe last reduction gear of torque booster in automotive transmission and transmits thevehicle directly. The requirements of dynamic performance is strict, not only meeting itsextreme space size limits, but also need to reduce its vibration as far as possible.Therefore the research on dynamic performance and dynamic optimization method ofwheel-side reducer has important theory significance and great engineering values onvibration reduction.The topic of this paper is supported by a company’s need to design a wheel-sidereducer, which is a crosswise project. The significance of this paper is to study how toestablish dynamic model with considering various factors in the design phase, andestimate the vibration response of the gear system, by using modern methods instead ofusing traditional methods, and by replacing static design with dynamic design. Then thepurpose of this thesis is to use the modern advanced design technology to design gearsystem device with an ideal low vibration. Comprehensive utilization of theories of gearengagement, the gear system dynamics, three dimensional static (dynamic) contactfinite element method and optimization design method, the dynamic performance andoptimize of dynamic response of wheel-side reducer have been carried out in this paper.The main research work in this paper can be summarized as follows:①The establishment of the wheel-side reducer’s coupling system dynamicanalysis model. Establish the sophisticated gear-shaft-bearing-box coupling dynamicanalysis model of wheel-side reducer system, on the basis of considering the gear meshdeformation, elastic deformation of support bearing, bolted joint on box and otherfactors.②The solution of the natural characteristic of the wheel-side reducer. Using themethod of block Lanczos to analyze the finite element modal of the reducer, the naturalfrequency and normal mode of the wheel-side reducer are obtained.③The numerical simulation of the wheel-side reducer’s internal dynamicexcitation. Taking the time-varying mesh stiffness, damping, tooth backlash,transmission error and other non-linear factors into consideration, the internal excitationincluding stiffness excitation, meshing impact exaction and error exaction is calculatedby three dimensional static contact finite element method, the dynamic contact finite element method and the approximation error method, and compose the internal dynamicexcitation of gear system. The internal excitation of the wheel-side reducer is givenquantitatively.④The simulation of the wheel-side reducer system’ dynamic response. Theinternal dynamic excitation is applied to the gear pair meshing line in the way of APDLcommand and flowing distribution load, analyzing dynamic coupling characteristic ofwheel-side reducer system of the structure parts and transmission parts with the modalsuperposition method, and then the vibration displacement, velocity and acceleration ofthe reducer are obtained⑤The optimal design of wheel-side reducer system’ dynamic response. Thedynamic response optimization model of the wheel-side reducer is established,considering the structure parameters of the wheel-side reducer box as design variables,volume as the state variable, and the RMS value of vibration acceleration of the nodeson the box as the objective function. The optimal solution of design variables areobtained after the dynamic response optimization of the wheel-side reducer with zeroorder optimization method. According to the optimal solution roundness value,wheel-side reducer dynamic analysis model is rebuilt, in order to evaluate dynamicperformance of the optimized reducer, the natural characteristics and dynamic responseof wheel-side reducer need to be recalculated with the same method beforeoptimization.