Abstract
The objective of this study was to investigate the grease-lubricated film-forming mechanisms in the finite line contact and to improve the grease-lubricated finite line contact’s film-forming capacity. An elastohydrodynamic lubrication (EHL) test rig with two interferometry microscopes, which could simultaneously monitor two different contact locations in the finite line contact, was constructed in order to study the influences of the grease thickener formulation on the film thickness and lubrication condition. By using the relative light intensity method, the thickness maps of the grease-lubricated film were calculated from the interferometer images captured by the two microscopes. The test results revealed that the grease thickener’s formulation had remarkable effects on film formation and the perturbation of film thickness. For the lithium-based grease, the film’s thickness near the two ends of the roller was prone to severe perturbation caused by the conglomeration of clumps that were hard to shear. For the aluminum-complex-based grease, the fibers tended to accumulate in the middle of the roller rather than at the two ends. The urea-based grease could be easily sheared into smaller particles. In addition to the straight-line profile rollers, the logarithmic profile rollers were tested and found to effectively enhance the axial grease flow, increase the axial shear stress, and thus shear more fibers into particles within the contact area.
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Lugt P M. Grease Lubrication in Rolling Bearings. New York (USA): John Wiley & Sons, 2013.
Vengudusamy B, Kuhn M, Rankl M, Spallek R. Film forming behavior of greases under starved and fully flooded EHL conditions. Tribol Trans 59(1): 62–71 (2016)
Cousseau T, Björling M, Graça B, Campos A, Seabra J, Larsson R. Film thickness in a ball-on-disc contact lubricated with greases, bleed oils and base oils. Tribol Int 53: 53–60 (2012)
Cann P M, Williamson B P, Coy R C, Spikes H A. The behaviour of greases in elastohydrodynamic contacts. J Phys D 25(1A): A124–A132 (1992)
Bingham E C. Fluidity and Plasticity. New York (USA): McGraw-Hill Book Co, 1922.
Herschel W H, Bulkley R. Measurement of consistency as applied to rubber-benzene solutions. Am Soc Test Proc 26: 621–633 (1926)
Greenwood J A, Kauzlarich J J. Inlet shear heating in Elastohydrodynamic lubrication. J Lubr Technol 95(4): 417–423 (1973)
Karthikeyan B K, Teodorescu M, Rahnejat H, Rothberg S J. Thermoelastohydrodynamics of grease-lubricated concentrated point contacts. Proc Inst Mech Eng Part C J Mech Eng Sci 224(3): 683–695 (2010)
Bordene L, Dalmaz G, Chaomleffel J P, Vergne F. A study of grease film thicknesses in elastorheodynamic rolling point contacts. Lubr Sci 2(4): 273–284 (1990)
Hurley S, Cann P M. Grease composition and film thickness in rolling contacts. NLGI Spok 63(4): 12–22 (1999)
Morales-Espejel G E, Lugt P M, Pasaribu H R, Cen H. Film thickness in grease lubricated slow rotating rolling bearings. Tribol Int 74: 7–19 (2014)
Cen H, Lugt P M, Morales-Espejel G. On the film thickness of grease-lubricated contacts at low speeds. Tribol Trans 57(4): 668–678 (2014)
Cyriac F, Lugt P M, Bosman R, Padberg C J, Venner C H. Effect of thickener particle geometry and concentration on the grease EHL film thickness at medium speeds. Tribol Lett 61: 18 (2016)
Cousseau T, Graça B, Campos A, Seabra J. Grease aging effects on film formation under fully-flooded and starved lubrication. Lubricants 3(2): 197–221 (2015).
Luo J B, Wen S Z, Huang P. Thin film lubrication. Part 1: Study on the transition between EHL and thin film lubrication using a relative optical interference intensity technique. Wear 194(1–2): 107–115 (1996)
Franco J M, Delgado M A, Valencia C, Sánchez M C, Gallegos C. Mixing rheometry for studying the manufacture of lubricating greases. Chem Eng Sci 60(8–9): 2409–2418 (2005)
Oikawa E, Inami N, Hokao M, Yokouchi A, Sugimura J. Bearing torque characteristics of lithium soap greases with some synthetic base oils. Proc Inst Mech Eng Part J J Eng Tribol 226(6): 575–583 (2012)
Lugt P M. Modern advancements in lubricating grease technology. Tribol Int 97: 467–477 (2016)
Acknowledgments
This work was funded by the twelfth five-year projects of China for science and technology under Contract D50-0109-12-001 and the Key Innovational Program of Shanghai Municipal Education Commission (No. 11ZZ89). The financial supports are greatly appreciated. The authors would like to thank Dr. Qingtao Yu of Aviation Industry Corporation of China for valuable suggestions.
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Zhijian WANG. He received his bachelor degree in mechanical engineering in 2010 from Jinan University, Shandong, China. At present, he is a PhD candidate in Shanghai University, China. His research interests include the rolling bearing tribology design.
Xuejin SHEN. She received the B.S. degree from Southeast University, China, and Ph.D. degree from Shanghai University, China, all in mechatronic engineering, in 1984, 2007, respectively. She became an associate professor in 2001, a full professor in 2009, in the Department of Mechanical Automation Engineering, Shanghai University. She is a senior member of Chinese Mechanical Engineering Society. Her research interest includes the performance analysis of rolling bearings, EHL of finite line contact, and mechanical model of MEMS.
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Wang, Z., Shen, X., Chen, X. et al. Experimental investigation of EHD grease lubrication in finite line contacts. Friction 7, 237–245 (2019). https://doi.org/10.1007/s40544-018-0208-8
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DOI: https://doi.org/10.1007/s40544-018-0208-8