Development of a screening method using a translatory oscillation tribometer (SRV®) to test extreme pressure and anti-wear properties of gear oils
Room: South Lobby
Raj Shah - Koehler Instrument Company, Inc.
- Cindy Klager - Koehler Instrument Company, Inc.
Gear Oils are used in a wide range of applications and depending on the application, different performance factors of the lubricant are important and must be evaluated. For many applications, including industrial machinery and automotive driveline components, it is ideal to have an antiscuff gear lubricant, or an extreme pressure (EP) type of lubricant. These types of lubricants typically have additives to enhance their load-carrying capacity making them ideal for heavy load, slow speed conditions.
Testing the scuffing load and extreme pressure properties of a gear oil is not a simple test. A test rig was developed by FZG (the Technical Institute for the Study of Gears and Drive Mechanisms of the Technical University in Munich, Germany) to measure the scuffing load capacity of lubricants as per ISO 14635. While this test provides vital information in regards to scuffing load, it is a very expensive and time consuming test to run and is not feasible to test every gear oil formulation that one might need. To help narrow down which gear oils should be tested using the FZG rig, a test was developed using the Translatory Oscillation Tribometer (SRV®) to screen gear oils and in addition, give complementary information by measuring the coefficient of friction, wear scar, and load carrying capacity.
The SRV® Tribometer is an invaluable tool for evaluating friction and wear properties which can now be applied to EP and Anti-wear (AW) testing of gear oils. The method used is based on DIN 51834-4 and is done on a translatory oscillation tester equipped for parallel movement. The results of the EP and AW tests on the SRV test rig are able to help characterize and differentiate gear oils in minimal time. The results are a good indication of how the lubricant will behave and serve as a pre-screener to determine which oils should go on for further bench tests and field use. In addition to the pre-screening results, this method will also yield results of coefficient of friction, wear volume and estimations for the load carrying capacity. This poster will show how the tests were developed, how the results compare to the FZG test and how the SRV can be used to provide a meaningful evaluation of gear oils.