For early failure problem of broken teeth of the first driving gear for gearbox in testing process

the failure mechanisms such as chemical composition inspection

fracture surface analysis as well as the metallographic structure morphology inspection analysis of failure gear hub are carried out.The results show that the main reasons causing abnormal fracture of the failure gear are the insufficient root strengthening of shot peening

the small groove fillet of the spline and the inadequate rim thickness.Using the finite element modeling

the contact stress analysis of failure gear is carried out and an improvement design method is put forward.