The Wear Behavior of Small Module Gears Lubricated with NLGI 1 Grease

ABSTRACT

Small module gears (m_n ≤ 1 mm) are increasingly important in power transmitting gear applications due to ever more rigorous requirements regarding, for example, performance and weight. They can be found in numerous applications that are subject to very different operating conditions. Often, small module gear applications are grease lubricated. This results in the lubrication supply mechanism (i.e., circulating and channeling) playing an important role in regard to the resultant gear failure mode. In the experimental investigations conducted herein, the focus was on gear sliding wear. The influence of the operating conditions and the grease composition on the lubrication supply mechanism, and thus wear behavior, was investigated using case-carburized, small module gears (m_n = 1 mm). The investigations show that the rotational speed has a significant effect on gear wear behavior. Increasing rotational speed does not necessarily lead to more favorable wear behavior of grease-lubricated gears. Furthermore, the grease composition was shown to affect wear behavior.

KEYWORDS:

• Wear
• gears
• greases
• bench wear tests

Funding

The IGF research project (17896 N) of the DGMK e.V. (Deutsche Wissenschaftliche Gesellschaft für Erdöl, Erdgas und Kohle e.V.) research association was sponsored through the AiF (Arbeitsgemeinschaft industrieller Forschungsvereinigungen) in the course of a program to support collective industrial research (IGF) by the German Federal Ministry of Economic Affairs and Energy.