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Comprehensive Theory of Viscous Coupling Operation
ISSN: 0148-7191, e-ISSN: 2688-3627
Published March 08, 2004 by SAE International in United States
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Viscous couplings continue to be an important part of modern automobile drive systems and provide a cost effective and reliable traction control system. Several million units are built into vehicles each year. While the operation of the viscous coupling under simple shear torque mode was reasonably well understood, its operation under ‘humping’ or torque amplified mode was not fully understood. Current explanations do not fully account for all observed phenomena and certainly cannot provide a simulation and design optimization tool.
This paper describes a comprehensive theory that utilizes thermodynamic, fluid mechanic, structural and mechanical analysis and verifies the mathematical model with a visual simulation tool and correlates the results to experimental observations. The proposed theory identifies, defines and explains the conditions necessary for initiating and sustaining the self-induced torque amplification that is the essential part of the ‘humping’ phenomena. The hypotheses are validated by the reasonable agreement of the model with test results.
|Technical Paper||Viscous Couplings in 4WD Vehicles: Application of Computational Modelling|
|Technical Paper||Induced Torque Amplification in Viscous Couplings|
|Technical Paper||The Development of Fluid for Small-Sized and Light Weight Viscous Coupling|
CitationMohan, S., "Comprehensive Theory of Viscous Coupling Operation," SAE Technical Paper 2004-01-0867, 2004, https://doi.org/10.4271/2004-01-0867.
SAE 2004 Transactions Journal of Passenger Cars: Mechanical Systems
Number: V113-6; Published: 2005-07-05
Number: V113-6; Published: 2005-07-05
- Peschke, W. 1986 “A Viscous Coupling in the Drive Train of an All-Wheel-Drive Vehicle,” SAE Technical Paper Series- 860386
- Taureg, I. H. Horst, J. 1990 “Induced Toque Amplification in Viscous Couplings,” SAE Technical Paper Series- 900557
- Takemura, T. Niikura, Y. 1990 “An Analysis of Viscous Coupling Torque Transmission Characteristics and Hump Phenomenon,” SAE Technical Paper Series- 900558
- Nakaoka, M. Kikuyama, K. Hasegawa, Y. Kojima, K. 1993 “Torque Amplification Phenomenon in Viscous Couplings (Effects of camber of inner disk blade),” Transactions of the Japan Society of Mechanical Engineers 59 561 44 51
- Wakamatsu, M. Yoshida, K. Kojima, Y. Murata, O. Mori, H. 1992 “Flow Analysis of Viscous Coupling,” ImechE FISITA Technical Papers-925056, C389/221 135 142
- Heuser, G. 1997 “An Approximate Solution for the Flow in Viscous Couplings,” Forsch Ingenieurwes 63 206 214 Springer-Verlag
- Mohan, S. K. Ramarao, B. V. Stephens, C. F. Varma, S. K. Gokul, B. V. 1992 “Viscous Couplings in 4WD Vehicles: Application of Computational Modeling,” SAE Technical Paper Series- 920611
- Mohan, S.K. 2002 “A Comprehensive Study of Self-induced Torque Amplification in Rotary Viscous Couplings,” Syracuse University Syracuse, NY
- Young, W. C. Budynas, R. G. 2002 “Roark's Formulas for Stress and Strain,” McGraw-Hill Book Company New York Seventh 401
- Schlichting, H. 1979 “Boundary-Layer Theory,” McGraw-Hill Book Company New York Seventh 116 122
- Kingsbury, A. 1931 “On Problems in the Theory of Fluid-Film Lubrication, with an Experimental Method of Solution,” Trans. Am. Soc. Mech. Engrs. 53 1931 59 75
- Needs, S. J. 1934 “Effects of Side Leakage in 120 Degree Centrally Supported Journal Bearings,” Trans. Am. Soc. Mech. Engrs. 56 1934 721 732 57 1935 135 138
- Fuller, D. D. 1984 “Theory and Practice of Lubrication for Engineers,” John Wiley & Sons New York Second 230
- Pan, C. 1998 “Numerical Analysis of Humping in Viscous Couplings,” Syracuse University Syracuse, NY
- Greenwood, J.A. Williamson, J. B. P. 1966 “Contact of Nominally Flat Surfaces,” Proc. Royal Society London 295 300 319
- Patir, N. Cheng, H. S. 1979 “Application of Average Flow Model to Lubrication Between Rough Sliding Surfaces,” ASME Journal of Tribology 101 220 230
- Megat Ahmad, M. M. H. Gethin, D. T. Claypole, T. C. Roylance, B. J. 1998 “Numerical and experimental investigation into porous squeeze films,” Tribology International 31 4 189 199