On Failure Problem of Gears Made From Very High Strength Steel

Some typical examples of failure of gears made from very high strength steel are shown and its trigger and whose causes are discussed: Many of such failure are triggered by tooth side edge contact or tooth tip edge contact and meshing-in of the wear debris. The limit of validity of the traditional methods for load carrying capacity of gears exists in the fact that they are based on the theory of contact of tooth flanks that realize conjugate or almost conjugate action of gears. To be able to design reliable gears made from very high strength steel, a principle is shown that suggests a new method for tooth form modification and of longitudinal crowing modification to avoid such failure. Metallurgical problem of gear material and special heat treatment aiming high surface hardness is also discussed.