Evaluation of Gear Oils for Mobile and Stationary Drives under Risk of Continuous Wear

There has long been a demand in industry for a standardised method for the reliable evaluation of gear oils with regard to their influence on the wear behavior of gears at low peripheral speeds. At present, the gear oil wear test according to DGMK 377 is the state of the art for the assessment of lubricant performance with regard to slow-running wear. However, due to the often high performance of modern gear oils, it is becoming increasingly difficult to differentiate the results obtained with this method. Also, the repeatability of the test does not yet meet the requirements of a standard test procedure, as an interlaboratory test from 2009 shows. In addition, the test, which is carried out with case-hardened test gears, only covers a limited range of practical applications. Thus, no statements can yet be made on the wear characteristics of other material pairings (e.g. hardened/tempered). The aim is therefore to research reliable methods of evaluating the wear behaviour of gear oils in tooth contact, taking into account the material pairing and practical boundary conditions.

The core of the research project consists of systematic theoretical and experimental investigations on gear stress test benches under wear-critical operating conditions with test gears of different material pairings and practical gear oils. The influence of different parameters on the wear behaviour and on the reliability of the obtained test results is evaluated. Furthermore, it is investigated to what extent the wear characteristics of the hardened/hardened material pairing can be converted to the hardened/tempered pairing and vice versa. The aim of the project is to obtain findings for the reliable evaluation of the wear behaviour of gear oils, which can be used to extend the gear oil wear test according to DGMK 377.

Cooperating Research Association: Forschungsvereinigung Antriebstechnik e.V.

DGMK Research Report 799 has been published.