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Full text release has been delayed at the author's request until August 09, 2026

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An Experimental and Theoretical Investigation of Tribo-dynamic Behavior and Power Losses of Ball Bearings

Dindar, Ahmet
http://orcid.org/0000-0002-2337-6516
http://rave.ohiolink.edu/etdc/view?acc_num=osu1625759098705088

Abstract Details

2021, Doctor of Philosophy, Ohio State University, Mechanical Engineering.
Although bearings provide low-friction interfaces between rotating components and their stationary housing, they are often responsible for a sizable portion of gearbox power losses. The current trends towards electrification of powertrains are likely to increase rotating speeds of drivetrains, making bearing performance even more critical. Physics-based modeling of a bearing that captures the coupling between its dynamic and tribological behaviors is required for simulation of bearing under such high-speed and high-load conditions. The main focus of this research is development and validation of such a model for deep-groove ball bearings. On the experimental side, a methodology to perform ball bearing power loss measurements under combined radial and axial loading conditions is developed. This methodology allows tight control of applied forces, bearing bulk and oil inlet temperatures, and rotational speed while measuring the torque loss precisely. A three-step procedure is devised to separate spin and mechanical components of power losses. Experimental parametric studies are performed to quantify the effects of various parameters on power losses. In the spin loss side, these parameters include speed, oil temperature (viscosity), oil flow rate, and bearing size. For mechanical losses, radial and axial force, speed and temperature are varied. Results of these parametric studies are compared to widely-used bearing power loss formulae available in the literature to assess their fidelity. Focusing first on the loading conditions causing the balls to stay loaded so that their individual motions are dictated by their race interfaces, a tribo-dynamic model of ball bearings operating at high speeds is developed by coupling a transient, point contact mixed EHL model into a singularity-free multi-body dynamic model. The model is employed to investigate mechanics of the ball-race contacts and ball motions, and to establish the sensitivity of the mechanical power loss to operating and lubrication conditions, and key design and manufacturing parameters. Its predictions are compared to measurements to demonstrate its accuracy within wide ranges of forces and speed. As the second phase of modeling effort, mostly radial loading conditions resulting in an unloaded zone are focused. As the balls lose contact with the races, various drag and hydrodynamic effects dictate the motions of the balls in the unloaded zone. Refined formulations for such effects are implemented in the earlier model to investigate complex ball and cage dynamic interactions. The model is then used to show such effects alter the mechanical power loss predictions only slightly such that the total power loss can practically be considered to be the sum of its spin and mechanical components.
Ahmet Kahraman (Advisor)
Robert Siston (Committee Member)
David Talbot (Committee Member)
Mechanical Engineering

Recommended Citations

Citations

  • Dindar, A. (2021). An Experimental and Theoretical Investigation of Tribo-dynamic Behavior and Power Losses of Ball Bearings [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1625759098705088

    APA Style (7th edition)

  • Dindar, Ahmet. An Experimental and Theoretical Investigation of Tribo-dynamic Behavior and Power Losses of Ball Bearings. 2021. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1625759098705088.

    MLA Style (8th edition)

  • Dindar, Ahmet. "An Experimental and Theoretical Investigation of Tribo-dynamic Behavior and Power Losses of Ball Bearings." Doctoral dissertation, Ohio State University, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=osu1625759098705088

    Chicago Manual of Style (17th edition)

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© 2021, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.
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