| As an important assembly of automobile transmission system,drive axle is one of the main vibration noise sources of automobile,which has a direct impact on vehicle NVH performance.Scholars at home and abroad have carried out a lot of research on vibration and noise reduction of drive axle and have made a series of important achievements.But the drive axle of the hypoid gear tooth surface complex design optimization of processing methods,processing elements of the gear pair meshing characteristics and the influence of vibration noise,multi-source excitation transmission system dynamic performance under the condition of market demand,cost,and low noise constraints optimization of tooth surface modification method,the dynamic response characteristics of drive axle shell optimization strategy and lubrication condition the effects of the hypoid gear noise is not can form a systematic method system.Therefore,this article based on the mechanism of drive axle vibration noise,based on the gear meshing principle,ease-off,the multi-objective optimization technology,etc.,the hypoid complex structure,drive axle gear tooth surface meshing characteristics,dynamic response analysis,optimization of tooth surface modification,the lubrication condition impact analysis in-depth research,paper main research work and conclusions are as follows:(1)Based on the gear meshing principle and the theory of differential geometry,the working tooth surface equations of large and small wheels were derived by forming(HFT)and developing(HGT)methods.Based on differential geometry and spatial meshing theory,geometric contact analysis model and loaded contact analysis model of tooth surface are derived.The differences of geometric transmission errors,loaded transmission errors,contact stress distribution,load distribution coefficient and contact impression of tooth surface of hypoid gear under HFT and HGT machining methods were compared and analyzed,which provided theoretical basis for selecting and optimizing the gear pair of drive axle and reducing vibration and noise.Based on the geometric contact analysis model and the loaded contact analysis model,the tooth surface contact impressions of HFT and HGT hypoid gears change with the amount of dislocation under different installation errors.A test platform was set up to verify it.The relevant analysis results can provide reference for further improving the transmission quality of gear pairs.(2)The correlation degree between each part of the drive axle main reducer and vibration noise is quantitatively analyzed.The correlation calculation model of each influencing factor was built,and the presetting optimization algorithm of low noise drive axle parts accuracy was proposed considering cost constraints.Obtain the optimal combination of design accuracy of each component.Then,according to the design accuracy,combined with ease-off active modification technology,the geometric transmission error and tooth surface impression are preset,and the ease-off surface and target tooth surface are accurately obtained.Taking the minimum load transmission errors amplitude as the optimization objective,the optimization scheme of the corresponding machining parameters of the wheel was obtained,and the transmission quality of the optimized hypoid gear pair was significantly improved compared with that before optimization.(3)Based on the centralized mass method,the dynamic analysis model of the transmission system under multi-source excitation was constructed,in which the comprehensive time-varying meshing stiffness,manufacturing error,installation error,clearance and meshing impact were taken into account.The dynamic response of hypoid gear transmission system under HFT and HGT machining methods was compared and analyzed,and the improvement of dynamic performance of HFT hypoid gear before and after optimization was verified.In addition,a parametric finite element model of the hypoid gear containing the actual machining tooth surface characteristics was established to analyze the dynamic response characteristics of the hypoid gear pair of the automobile drive axle under real working conditions,which provides an analysis method for the optimal design of the dynamic performance of the automobile drive axle.(4)Combining with the finite element model of the drive axle housing,the resonance excitation source was obtained by modal analysis,frequency response analysis and noise radiation analysis.The optimization region of the drive axle housing was determined accurately,and the structural optimization design was completed with the method of structural topology optimization.The whole system construction from model construction,excitation analysis to resonance noise analysis,drive axle housing structure optimization and verification is realized.In addition,theoretical analysis was carried out on the correlation between gear lubricating oil,friction noise and stirring noise,and the influence characteristics of lubricating oil viscosity and gear oil immersion depth on gear friction noise and gear stirring noise were obtained.Combined with the driving axle fuel volume and noise bench test platform,the function relationship between the immersion depth and lubricating oil viscosity of driven gear,friction noise and stir noise is constructed,which provides guiding significance for the design of optimal immersion depth and viscosity of theoretical gear.(5)Based on the above research,the rolling test and vibration test of the HFT hypoid gear pair of the drive axle main reducer were carried out to compare the contact impression and vibration response of the tooth surface before and after optimization,and the test results were compared with the theoretical simulation results,which fully verified the rationality of the machining parameter design and the correctness of the simulation analysis.In addition,the NVH test of the vehicle after the overall optimization of the drive axle shows that the vibration and noise of the vehicle after the overall optimization is better than that before the optimization. |
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