Influence Of Gear Modification On Its Transmission Characters With Consideration Of Thermal Deformation

Gear transmission system withstands large temperature rise in the practical working process. It will cause thermal deformation of tooth profile, which can lead to vibration, noise and meshing impact between gear pair. It will also increase the gear meshing power loss and reduce the transmission efficiency. Considering thermal deformation and modification of tooth profile, the article establishes the nonlinear dynamic model of spur gear and helical gear system, and aims to analyze the transmission character of different types of tooth profile.Firstly, considering two different types of tooth profile error-thermal deformation and modification of tooth profile, meshing stiffness of spur gear is calculated, and thus deducing the maximum value of tooth profile modification. Dynamic model of spur gear transmission systems with tooth profile error is built by using centralized mass method. The article analyzes the influence of different values and curves of modification on the noise and vibration of spur gear transmission system under different working conditions, and the meshing impact improvement with different tooth profile modification curves. Then the author also introduces calculation method of helical gear pair’s meshing stiffness and analyzes effect of helix angle modification on noise and vibration of helical gear transmission system. Above analysis results provide theoretical support for the modification work of gear with thermal deformation. In addition, this article studies the gear load distribution in practical working condition, establishes the calculation method of gear meshing power loss and transmission efficiency, and analyzes the influence of tooth profile modification on transmission efficiency under different working conditions.The analysis results show that:Appropriate tooth profile modification can significantly reduce the mesh impact, vibration and noise in the meshing process, and improve the transmission efficiency. Under different load and speed conditions, the results of the different methods of modification are not the same. Therefore, in the process of gear designing and manufacturing, Corresponding modification method should be adopted to maximize the increase of transmission characters of gear system under different working conditions.