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Development of a generalized mechanical efficiency prediction methodology for gear pairs

Xu, Hai
http://rave.ohiolink.edu/etdc/view?acc_num=osu1128372109

Abstract Details

2005, Doctor of Philosophy, Ohio State University, Mechanical Engineering.
In this study, a general methodology is proposed for the prediction of friction-related mechanical efficiency losses of gear pairs. This methodology incorporates a gear contact analysis model and a friction coefficient model with a mechanical efficiency formulation to predict the gear mechanical efficiency under typical operating conditions. The friction coefficient model uses a new friction coefficient formula based on a non-Newtonian thermal elastohydrodynamic lubrication (EHL) model. This formula is obtained by performing a multiple linear regression analysis to the massive EHL predictions under various contact conditions. The new EHL-based friction coefficient formula is shown to agree well with measured traction data. Additional friction coefficient formulae are obtained for special contact conditions such as lubricant additives and coatings by applying the same regression technique to the actual traction data. These coefficient of friction formulae are combined with a contact analysis model and the mechanical efficiency formulation to compute instantaneous torque/power losses and the mechanical efficiency of a gear pair at a given position. This efficiency prediction methodology is applied to both parallel axis (spur and helical) and cross-axis (spiral bevel and hypoid) gears. In the case of hypoid gears, both face-milling and face-hobbing processes are considered, and closed-form expressions for the geometric and kinematic parameters required by the efficiency model are derived. The efficiency prediction model is validated by comparing the model predictions to a set of high-speed spur gear efficiency measurements covering several gear design and surface treatment variations. The differences between the predicted efficiency values and the measured ones are consistently within 0.1 percent. Influence of basic gear design parameters, tooth modifications, operating conditions, surface finish and treatments, lubricant properties, and manufacturing and assembly errors on mechanical efficiency of both parallel-axis and cross-axis gears are investigated. At the end, a set of guidelines is provided on how to improve mechanical efficiency of gear pairs through design, surface engineering and lubricant solutions.
Ahmet Kahraman (Advisor)
233 p.
Engineering, Mechanical
Mesh friction; Efficiency; Lubrication; EHL; Power loss; Sliding friction; Hypoid gear; Helical gear

Recommended Citations

Citations

  • Xu, H. (2005). Development of a generalized mechanical efficiency prediction methodology for gear pairs [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1128372109

    APA Style (7th edition)

  • Xu, Hai. Development of a generalized mechanical efficiency prediction methodology for gear pairs. 2005. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1128372109.

    MLA Style (8th edition)

  • Xu, Hai. "Development of a generalized mechanical efficiency prediction methodology for gear pairs." Doctoral dissertation, Ohio State University, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=osu1128372109

    Chicago Manual of Style (17th edition)

osu1128372109
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© 2005, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.