Experiments on the High-Power and High-Temperature Performance of Gear Contacts

Autor: Olson, Garrett Weston
Jazyk: angličtina
Rok vydání: 2012
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Druh dokumentu: Text
Popis: In this study, gear contact tests were performed using a recently developed test methodology capable of both high-power (pitch-line velocities up to 50 m/s and pinion torques up to 450 N-m) and high-temperature (oil inlet temperatures up to 150C) operating conditions. Test specimens and operating conditions were chosen in order to simulate high-power automotive and aerospace applications. Automotive test specimens were made from a typical automotive transmission gear steel, SAE 4118M, at surface roughnesses typical of hard ground gears. Aerospace test specimens were made out of a high performance (high-temperature) proprietary gear steel. These aerospace specimens were either chemically polished or super-finished following grinding to achieve roughness amplitudes more than 10 times smoother than typical ground surfaces. Throughout each test interim inspections were used to identify and monitor failure modes. Experimental testing for automotive applications is shown to consistently produce contact fatigue failures in the form of micro-pitting and macro-pitting. Tests were suspended when macro-pits exceeded the test methodologies pre-determined failure criteria. Experimental testing for aerospace applications is shown to be absent of any contact fatigue failures due to the extremely smooth contact surfaces. The primary mode of contact failure in aerospace tests is observed to be scuffing.
Databáze: Networked Digital Library of Theses & Dissertations
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