M.S. Thesis Defense: "Hydrodynamic Lubrication of Gearboxes: Measuring Oil Film Thicknesses between Gear Teeth"

Event Type: 
Daniel Cox
Thursday, May 2, 2013 - 3:00pm to 4:00pm
1210 Lurie Engineering Center

The mechanical power transmission efficiency and reliability of gears is highly dependent on the lubrication condition between the gear teeth. While the ideal amount of lubrication can be generally predicted, an effective in-situ measurement of oil film thicknesses between loaded gear teeth has proved elusive. This study explores two novel oil film thickness measurement techniques for geared applications: optical fluence, based on the energy of light transmitted between loaded gear teeth; and neutron radiography, based on the attenuation of neutrons due to the presence of oil films. A gear testing apparatus was designed and built to be used with both techniques. It allowed independent control of gear rotation rate, load torque, and oil flow. Film thickness measurements made with the optical technique ranged from 0.3 – 10.2 mil. These results were compared with film thickness measurements made in an earlier study, as well as with predictions from two different film thickness models: a simple model developed for the purposes of this study and the industry-accepted model as described by the American Gear Manufacturers Association. In each case, the measured film thicknesses were larger than the predictions, though these discrepancies might be attributed to specifics in the oil delivery system, the test gears, and the chosen range of parameters investigated. In addition to the optical measurements, a proof-of-concept test for the neutron technique was performed, and a full range dynamic experiment was planned. While performing the full neutron experiment fell outside the scope of this study, the technique is shown to be promising.

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