As shown in the figure, the failure zone diagram of automobile gear transmission made by Nieman, Professor of Munich University of technology, Germany, shows that the bending and bending strength of automobile gear is lower than that of tooth surface.
However, in recent years, due to the research and development results of automobile gear surface shot peening strengthening technology, the bending fatigue strength life limit of automobile gear has been greatly improved. The bending fatigue strength limit of automobile gear exceeds the pitting corrosion fatigue strength limit of tooth surface contact. How to further improve the contact fatigue strength limit of automobile gear has become the most important research topic of high-strength automobile gear technology.
Under the repeated action of high contact stress on tooth surface and tensile stress caused by rapid relative sliding of tooth surface meshing, automobile gear pair will produce tooth surface fatigue damage. In order to prevent this kind of damage, the surface integrity and anti tooth fatigue performance of automobile gear pair can be effectively improved by using the modified coating technology of automobile gear tooth surface.