Quasi-static transmission error behavior under the composite effect of temperature and load

Résumé

Technological trends in automotive and aeronautical industriesare pushing geared powertrains towards high rotational speedswith pitch line velocities approximating 100 m/s (Ref. 1), largegear ratios with low number of stages (Ref. 2) and minimum oilimmersion depths (Ref. 3). At such conditions, thermo-mechanical issues are expected as bearings and gears are close to theirthermal capacities.Field experience in the turbomachinery industry has longproved that high-speed gearing is prone to thermal distortioneffects. However, much of the knowledge remains restrictedto the field of application and it is not available in the openliterature. Seminal experimental work by Welch and Boron(Ref. 4) showed that in helical gear drives with relatively largeface widths, the temperature of the teeth rises non-uniformlyacross the face width due to axial oil pumping. Longitudinalthermal gradients result in an uneven load distribution alongthe tooth trace and the authors pointed out that this behaviorcould be regenerative until tooth failure occurs. Subsequentworks by Martinaglia (Ref. 5), Akazawa (Ref. 6), Matsumoto etal. (Ref. 7) and Amendola et al. (Ref. 8) prove such behavior andeven numerically correlate thermal gradients to tooth root stressincrease (Ref. 9).