Alternative Materials, Composites and Coatings

Plastic gears can be advantageous in specific transmission applications. The high material damping has a positive effect on the noise behaviour, the low mass and mass inertia can be distinguished in transmissions, which are subject to high accelerations. A central advantage of plastic gears is their dry run capability. This makes them ideal for applications e.g. in the field of medical technology, food processing or the printing industry, where lubrication is not possible for functional or hygienic reasons. High friction losses in the dry run capability of plastic gears limit the transmittable power from a thermal viewpoint. Loss-optimised gears exhibit significantly lower friction losses by concentrating the meshing around the pitch point.

A composite structure, in which the teeth are made of steel and the wheel body is made of plastic, combines the advantages of steel and plastic gearings. Besides increasing the lightweight design potential, it is possible to favourably manipulate the dynamic system behaviour by using composite gears.

Moreover the tribological properties and the flank load-carrying capacity of steel gearings can be optimised by using extremely hard coatings e.g. amorphous carbon coatings. The impact of such coatings on efficiency and fatigue life is investigated at FZG.