The purpose of gear modification is to make the pressure distribution on the tooth surface as uniform as possible after the gear is loaded and deformed, and the gear teeth can still operate smoothly after the tooth profile is deformed, so as to reduce the meshing in and meshing out impact, so as to reduce the vibration and noise of the gear system.
B. W. Dudley et al. Used the step-by-step approximation method to solve the bending and torsional deformation and comprehensive deformation of herringbone gear shaft, and determined the gear modification curve and modification amount according to the bending and torsional deformation and comprehensive deformation of gear shaft. Zhang et al. Studied the influence of helical gear tooth surface modification on transmission error of helical gear system under load by using dynamic model. Parag wagaj and others analyzed the influence law of helical gear profile modification on its static transmission error by using nonlinear finite element method. Through tooth profile modification, the static transmission error of helical gear system can be reduced to a certain extent. Bruy è re et al. Introduced a multi-objective analysis algorithm for simplified tooth profile modification optimization of spur and helical gears to reduce the fluctuation of variable transmission error and optimize the load distribution on the tooth surface. Zhang et al. Analyzed the influence law of tooth profile modification and tooth drum modification on transmission error and whistling of helical gear transmission by using Windows LDP software. The research shows that gear modification can effectively reduce transmission error of driving wheel and gear whistling. P. Velex et al. Studied the influence of tooth profile modification on and transmission error of spur and helical gears with narrow tooth width by using multi degree of freedom dynamic model, considered the modification amount in the form of Fourier series, and proposed a unique scalar equation of transmission error. The fluctuation of transmission error depends on the definition of gear geometric parameters and modification amount, and compared with other numerical calculations.
Yuan Ye et al. Analyzed various factors of gear noise, introduced the concept and types of gear modification, and proposed that gear modification is an important method to reduce gear noise. Fang Zongde et al. Proposed a finite element calculation program for helical gear modification. The program can automatically generate the finite element mesh model of helical gear teeth and the mating contact line of meshing teeth, and calculate the flexibility matrix of helical gear contact teeth to the corresponding nodes on the contact line; Considering the comprehensive deformation of gear support structure and helical gear teeth, the optimal tooth surface modification parameters are obtained by mathematical programming method. Fan Xiting uses the finite element analysis software ANSYS ls_ DYNA carries out the meshing static and dynamic contact analysis of transmission helical gear. The research results show that the gear contact stress after helical gear profile modification and tooth direction modification is significantly reduced. Tang zengbao et al. Established the dynamic model of gear system by comprehensively considering the manufacturing error of gear teeth, meshing stiffness change error and equivalent modification error, solved the mathematical model by numerical method and adjusted the relevant parameters in the model, so as to determine the best modification method. According to the method of tooth profile modification of helical gear, Chen runlin uses modification parameters and considers the modification amount of helical gear, establishes the single degree of freedom torsional vibration model of helical gear, and analyzes the influence of modification parameters on torsional vibration for four modification curves: straight line, parabola, exponential function curve and trigonometric function curve.
To sum up, for the research of helical gear modification, the finite element method is mostly used to calculate the influence of modification on gear strength. Some scholars have studied the influence of modification on gear dynamic response characteristics, but the gear modification is described in the form of Fourier series or simplified error function.