| As the electric vehicle increases the braking energy recovery condition,the differential,as a part of the transmission device,puts forward higher requirements on the gear fatigue life.In this paper,numerical analysis,orthogonal experiment and experimental research are combined to study the shape modification and optimization of differential gear of electric vehicle to improve its fatigue life.Firstly,CATIA was used to build parametric model of differential gears,and the threedimensional model of planetary gears and semi-axial gears was established.Through finite element modeling and simulation analysis of differential gears,it was concluded that the highest point of single tooth meshing was the maximum point of tooth surface contact stress and tooth root bending stress,and compared with the theoretical calculation results,it was concluded that the strength of planetary gears meets the requirements.Secondly,determined the interval of tooth profile modification,tooth modification,tooth modification factor Ⅰ and modification factor Ⅱ,and using KISSsoft,analysis of peak transmission error difference,the maximum contact stress of tooth surface,the planet gear and axle shaft gear tooth root bending stress biggest.The results showed that the tooth profile modification had the greatest influence on the peak transmission error difference and the maximum bending stress of the planetary gear root,and the tooth profile modification had the greatest influence on the maximum contact stress of the tooth surface.The tooth profile modification has the least effect on the maximum bending stress of axle shaft gear.After full factorial experiment by Minitab establish regression model,the amount of four response obtained the optimum modification scheme of planetary gear: tooth profile modification and tooth modification was 40 microns and 10 microns,modification factor Ⅰ was0.363 and the modification factor Ⅱ was 0.5.Finally,the contact stress and root bending stress of planetary gear are analyzed by finite element simulation under driving and braking conditions.The tooth contact fatigue damage and root bending fatigue damage of the modified planetary gear were calculated by n Code,and the differential gear bench test was carried out.The results showed that the fatigue damage of the modified planetary gear was reduced and the gear modification optimization was feasible. |
