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Tribodynamics of Right Angled Geared System

C Gopalakrishnan, Srikumar
http://orcid.org/0000-0002-4810-7785
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1540566189193567

Abstract Details

2018, PhD, University of Cincinnati, Engineering and Applied Science: Mechanical Engineering.
Hypoid and spiral bevel gears are used to transmit power at a right-angle. They are generally used in automobiles, trucks, and earthmovers. This right-angle power transmission system is often plagued with severe noise and vibration problems. The source of this noise is due to the transmission error, which depends on the surface roughness of the meshing gear teeth, tooth profile errors, tooth deformations under the operating conditions, and misalignments. The surface roughness of the gear teeth affects the lubricant pressure. So, it is important to study the contact phenomenon that occurs in the meshing teeth to gain a better understanding of the powertrain gear noise problems. Thus, it is useful to study both the dynamics and the tribological parameters together. Tribodynamics refers to the study of effect of tribology on the dynamics of the contacting surfaces. Thus, the primary objective of this work is to develop a tribodynamic model for right-angled gear dynamics. This would enable a driveline analyst to study the combined effect of tribology and dynamics of the gears. This work aims to build a numerical model of the elastohydrodynamic lubrication in hypoid and spiral bevel gears. Therefore, a friction model is developed based on the full elastohydrodynamic lubrication and parametric studies are performed. The right-angle geared system is subjected to both rolling and sliding motions. Hence the study of contact parameters was performed based on the sliding and rolling motions that occurs at that position of the contact. This information is useful to the engineers to design the gear contact patterns in hypoid and spiral bevel gears. There are several dynamic parameters which can be synthesized from the elastohydrodynamic lubrication. In this work the damping and coefficient of friction are synthesized from the elastohydrodynamic lubrication. The time varying damping can be calculated from the elastohydrodynamic lubrication, which is more reasonable than using constant damping for various operating conditions and contact conditions. The damping is introduced into the dynamic calculation in general by the viscous damper. However, the friction between the contacting surfaces also introduces some damping into the dynamic response. Thus, in this work the friction is synthesized from the elastohydrodynamic lubrication and it is used in the dynamic calculation. In this manner, the friction calculated will be more realistic and is expected to yield a realistic response due to the lubricant film entrained between the contacting surfaces. The effect of assembly errors on the right-angle geared system leads to an increase in the dynamic response. These assembly errors change the contact pressure pattern and the combination of sliding and rolling motions in the right-angle geared system. Thus, the interactions between the friction and the assembly error is also studied in this work. Integrated dynamics of the spiral bevel gears with mixed elastohydrodynamic lubrication is presented in this work. The dynamic parameters like oil film stiffness and the friction coefficient are included in the dynamic response of the spiral bevel gears. The response calculated in this manner will include the effect due to the lubricant entrainment between the meshing gear surfaces. In this research, an elliptical point contact lubrication model was formulated to model the lubricant entrainment at high loads. An asymmetric elliptic point contact model is also formulated to consider the asymmetric contact pattern, which is common in right-angle geared system. The side leakage is modelled by considering the velocity of flow in both the principal axes of the elliptical point contact.
Jay Kim, Ph.D. (Committee Chair)
Manish Kumar, Ph.D. (Committee Member)
Teik Lim, Ph.D. (Committee Member)
David Thompson, Ph.D. (Committee Member)
145 p.
Mechanical Engineering
Elastohydrodynamic lubrication; Hypoid gears; Spiral bevel gears; Oil film stiffness; Damping due to lubricant; Tribodynamics

Recommended Citations

Citations

  • C Gopalakrishnan, S. (2018). Tribodynamics of Right Angled Geared System [Doctoral dissertation, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1540566189193567

    APA Style (7th edition)

  • C Gopalakrishnan, Srikumar. Tribodynamics of Right Angled Geared System. 2018. University of Cincinnati, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1540566189193567.

    MLA Style (8th edition)

  • C Gopalakrishnan, Srikumar. "Tribodynamics of Right Angled Geared System." Doctoral dissertation, University of Cincinnati, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1540566189193567

    Chicago Manual of Style (17th edition)

ucin1540566189193567
274
© 2018, all rights reserved.
This open access ETD is published by University of Cincinnati and OhioLINK.
Release 3.2.12