Wedeven Associates (United States)

'Loss of Lube' testing was conducted to experimentally evaluate benefits of Lubricants and Coatings to extend the time to failure for gears and bearings that are experiencing a loss of lubrication event. In this project, the testing of Loss of Lubrication technologies were divided into two categories; Ball-on-Disk screening testing and Gear Specimen Testing. The Ball-on-Disk screening tests were performed at Wedeven Associates using their patented WAM testing apparatus. The screening tests were divided into three 'waves' of testing which consisted of lubricant tests (Wave 1), coating tests (Wave 2) and lubricant-coating refinement testing (Wave 3). Wave 3 testing used the best performing lubricants and coatings from Wave 1 and Wave 2, respectively, to establish consistent results and identify any potential anomalous results from the first two waves of screening testing. The second portion of this study was to perform actual loss of lubrication testing on spur gears at Penn State's Gear Research Institute. Using the data obtained from the Ball-on-Disk screening tests, 3.5" PD spur gears of various base material steels were fabricated, many of them with coated teeth, and subjected to loss of lubrication conditions under load to assess their ability to perform without proper lubrication.

Description STP 1404 addresses various aspects of bench test selections and limitations, along with lubrication and wear simulations. Bench tests are commonly used to evaluate the lubrication and wear properties of industrial fluids when used in various types of machinery. They are often used without any validation of the lubrication and wear properties obtained in the machinery being modeled -- this has been a long-standing problem in the lubricants industry. This book attempts to address this problem. 23 peer-reviewed papers cover: Problems of Bench Testing--discusses various difficulties associated with bench test selection, particularly as the test results correlate with equipment lubrication. Some suggestions to address equipment lubrication correlation problems are: selection of appropriate test conditions, development of custom-made test equipment, and use of lubrication and wear simulations to identify appropriate test conditions. Bench Tests and Test Development--examines proper design considerations and model validations to successfully apply bench tests in lubrication and wear analysis. Analysis--addresses a wide range of methodologies for evaluation of bench test results. These include examination of experimental test parameters, detection of boundary and EHD lubrication transitions, wear mode identification by debris analysis, and the utility of tribological aspect numbers. Modeling and Simulation--outlines the value and necessity of experimental simulation of tribological performance to properly evaluate machinery lubrication and wear problems.

<div class="htmlview paragraph">Traction drive continuously variable transmissions (TCVTs) are under active investigation by a number of OEMs and suppliers. Along with advances in control systems and metallurgy, improved traction fluids will be key to successful implementation of this technology. Traction fluids will need to function over a wide range of temperatures and contact pressures. Contact pressures may reach as high as 4 GPa, while temperatures may range from about - 40 C to about 140 C. It is widely recognized that low temperature fluidity at start-up is an issue, since fluids which give high traction coefficients and adequate viscosity under normal operating temperatures generally exhibit high viscosity at low temperatures. However, fe published data are available on traction behavior at temperatures below about 20 C and at contact pressures above about 2 GPa. Since published data are an inadequate guide to traction behavior under extreme conditions, we have extended our traction measurements to contact pressures as high as 3.7 GPa and to temperatures as low as - 20 C, using point contact traction machines. The results show that traction can drop dramatically at temperatures below about 20 C, indicating potential operating problems at low temperatures. This effect needs to be taken into account when designing hardware and must be a focus of future fluid development.</div>