Tribological transfer mechanisms and large-area micro contact simulation of solid lubricant supply from PVD layers for dry-running gear stages

 

Starting Situation

In gear drives, a lubricant in the form of lubricating oil or grease is usually used as an intermediate medium. The primary tasks of the lubricant are friction reduction and heat dissipation. Due to the different tribological stresses in tooth flank contact compared to bearings and seals, heat dissipation in particular poses a challenge, the realisation of which has been the subject of research to date in dry operation of highly stressed gear contacts.

Research Objective

The aim of the research project is the experimental and simulative analysis and modelling of the supply and transfer mechanisms of PVD solid lubricant systems for the supply of dry rolling contact using the example of tooth flank contact. In order to assess the layer load bearing capacity, contact friction and heat generation, the test specimens coated with different layer variants are tested on the two-disc test rig under gear-typical conditions. The test specimens are characterized analytically and tribologically in order to develop a basic understanding of the coating preparation and transfer processes as a function of the surface properties. Based on these findings, a method for tribosimulation of dry contact will be developed. In the last step, the results of the experimental, analytical and tribological investigations will be used to develop a layer system suitable for the stress and to transfer it to tooth flank surfaces that are locally and temporally variable with regard to tribological stress. In order to prove the application capability, test toothings are adjusted and examined according to the optimised surface and layer properties from the disc test.