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Microgeometrical tooth profile modification influencing efficiency of planetary hub gears

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posted on 2017-08-10, 12:41 authored by Ehsan Fatourehchi, Mahdi Mohammadpour, Paul KingPaul King, Homer Rahnejat, G. Trimmer, B. Womersley, A. Williams
Planetary hub systems offer desired speed and torque variation with a lighter, compact and coaxial construction than the traditional gear trains. Generated friction between the mating teeth flanks of vehicular planetary hubs under varying load-speed conditions is one of the main sources of power loss. Modification of gear tooth geometry as well as controlling the contacting surface topography is the remedial action. The paper studies the effect of tooth crowning and tip relief upon system efficiency. It includes an analytical elastohydrodynamic analysis of elliptical point contact of crowned spur gear teeth. The analysis also includes the effect of direct contact of asperities on the opposing meshing surfaces. Tooth contact analysis (TCA) is used to obtain the contact footprint shape as well as contact kinematics and load distribution. A parametric study is carried out to observe the effect of gear teeth crowning and tip relief with different levels of surface finish upon the planetary hubs’ power loss.


The authors wish to express their gratitude to Innovate UK under the off-highway research initiative and JCB for the financial support extended to this research and development project.



  • Mechanical, Electrical and Manufacturing Engineering

Published in

International Journal of Powertrains


FATOUREHCHI, E. ... et al, 2018. Microgeometrical tooth profile modification influencing efficiency of planetary hub gears. International Journal of Powertrains, 7 (1/2/3), pp.162-179.


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  • AM (Accepted Manuscript)

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This work is made available according to the conditions of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) licence. Full details of this licence are available at: https://creativecommons.org/licenses/by-nc-nd/4.0/

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This paper was published in the journal International Journal of Powertrains and the definitive published version is available at https://doi.org/10.1504/IJPT.2018.10011451.






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