Lubricants

Determination of the Load Capacity of Gear Pairings under Spray Lubrication with Flow Greases

The first aim of this research project is to review the transferability of the results from the test procedure A/2.8/50 acc. to ISO 14635-3, which is carried out on the FZG backto- back gear test rig under dip lubrication, regarding the scuffing load capacity and wear behavior of flow greases with regards to the particularities of spray lubricated gear drives. Therefore, systematic experimental investigations are carried out, following the standardized test procedure, but under spray lubrication. The test results are evaluated in connection with results from dip lubrication tests. On the basis of these investigations, recommendations are given for the determination of scuffing and wear characteristics of flow greases in bench tests. The second aim is to review the calculation method for the pitting load capacity acc. to ISO 6336 with regards to grease lubricated gears. Prior investigations show lower load capacity for gears in the material pairing case-hardened/through-hardened when lubricated with grease in comparison to the lubrication with oil. The calculation method does not cover this discrepancy. On the basis of systematic load capacity tests under spray lubrication and a connected evaluation of former test results under dip lubrication, recommendations for the application and modification of the calculation method are given.

The IGF project (18464 N) of the research association DGMK Deutsche Wissenschaftliche Gesellschaft für Erdöl, Erdgas und Kohle e.V., Überseering 40, 22297 Hamburg was funded via the AiF within the framework of the programme for the funding of Industrial Collective Research (IGF) by the Federal Ministry for Economic Affairs and Energy on the basis of a resolution of the German Bundestag.