Abstract
Microoscillation is a typical case of transient motion, which occurs in many machine elements, including rolling or sliding element bearings, cams, and gears. Wear is easy to occur on the surface of such elements, particularly at the end point of the stroke, where the surfaces are momentarily static. In the present work, an experimental investigation is conducted to explore the grease film behavior of point contact lubrication during microoscillation in the case of pure rolling or pure sliding. The technique of relative optical interference intensity was used to monitor the variation of the grease film thickness and the motion of the grease in the contact area through analyzing the captured interferograms. Experimental results indicate that a crescent-shaped grease film can form along the motion direction in the contact area under microoscillation. The grease film is formed in the inlet region, and the film thickness remains while moving in the Hertzian contact area. In the case of pure rolling, the crescent-shaped grease film and the initial entrapped grease film are carried by a tow effect of moving interfaces in the contact area. However, in the case of pure sliding, there are relative motions in the sliding direction at the two interfaces of the grease/ball and the grease/disk in the Hertzian contact area. The shape of the entrapped grease remains almost unchanged while moving in the Hertzian contact area. During the repetition of microoscillations, the crescent-shaped grease film thickness drops gradually.
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References
Cann, P.M.: Starved grease lubrication of rolling contacts. Tribol. Trans. 42, 867–873 (1999)
Cann, P.M., Lubrecht, A.A.: An analysis of the mechanisms of grease lubrication in rolling element bearings. Lubr. Sci. 11, 227–245 (1999)
Wedeven, L.D., Evans, D., Cameron, A.: Optical analysis of ball bearing starvation. Trans. ASME J. Lubr. Tech. 93, 349–363 (1971)
Palacios, J.M., Cameron, A., Arizmendi, L.: Film thickness of grease in rolling contacts. Tribol. Trans. 24, 474–478 (1981)
Cann, P.M.: Grease lubrication of rolling element bearings-role of the grease thickener. Lubr. Sci. 19, 183–196 (2007)
Cann, P.M., Williamson, B.P., Coy, R.C., Spikes, H.A.: The behaviour of greases in elastohydrodynamic contacts. J. Phys. D Appl. Phys. 25, A124–A132 (1992)
Glovnea, R.P., Spikes, H.A.: Behavior of EHD films during reversal of entrainment in cyclically accelerate/deceleration motion. Tribol. Trans. 45, 177–184 (2002)
Sugimura, J., Jones, W.R., Spikes, H.A.: EHD film thickness in non-steady state contacts. ASME J. Tribol. 120, 442–452 (1998)
Glovnea, R.P., Spikes, H.A.: Elastohydrodynamic film formation at the start-up of the motion. Proc. Inst. Mech. Eng. J: J. Eng. Tribol. 215, 125–138 (2001)
Kalin, M., Joze, V.: The tribological performance of DLC coatings under oil-lubricated fretting conditions. Tribol. Int. 39, 1060–1067 (2006)
Kaneta, M., Takeshima, T., Togami, S., Nishikawa, H.: Stribeck curve in reciprocating seals. Proc. 18th Int. Conf. On Fluid Sealing, pp. 333–347 (2005)
Ikeuchi, K., Fujita, S., Ohashi, M.: Analysis of fluid film formation between contacting compliant solids. Tribol. Int. 31, 613–618 (1998)
McColl, I.R., Waterhouse, R.B., Harris, S.J., Tsujikawa, M.: Lubricated fretting wear of a high-strength eutectoid steel rope wire. Wear 185, 203–212 (1996)
Zhou, Z.R., Kapsa, P.h., Vincent, L.: Grease lubrication in fretting. ASME J. Tribol. 120, 737–743 (1998)
Glovnea, R.P., Spikes, H.A.: The influence of lubricant on film collapse rate in high pressure thin film behaviour during sudden halting of motion. Tribol. Trans. 43, 731–739 (2000)
Luo, J.B., Wen, S.Z., Huang, P.: Thin film lubrication. Part I. Study on the transition between EHL and thin film lubrication using a relative optical interference intensity technique. Wear 194, 107–115 (1996)
Luo, J.B., Shen, M.W., Wen, S.Z.: Tribological properties of nanoliquid film under an external electric field. J. Appl. Phys. 96, 6733–6738 (2004)
Li, G., Zhang, C.H., Luo, J.B.: Film-forming characteristics of grease in point contact under swaying motions. Tribol. Lett. 35, 57–65 (2009)
Guo, F., Wong, P.L., Geng, M., Kaneta, M.: Occurrence of wall slip in elastohydrodynamic lubrication contacts. Tribol. Lett. 34, 103–111 (2009)
Wong, P.L., Lingard, S., Cameron, A.: The high-pressure impact microviscometer. STLE Tribol. Trans. 35, 500–508 (1992)
Kaneta, M., Ozaki, S., Nishikawa, H., Guo, F.: Effects of impact loads on point contact elastohydrodynamic lubrication films. Proc. IMechE J: J. Eng. Tribol. 221, 271–278 (2007)
Dowson, D., Jones, D.A.: Lubricant entrapment between approaching elastic solids. Nature 214, 947–948 (1967)
Kaneta, M., Nishikawa, H., Kameishi, K.: Observation of wall slip in elastohydrodynamic lubrication. ASME J. Tribol. 112, 447–452 (1990)
Kauzlarich, J.J., Greenwood, J.A.: Elastohydrodynamic lubrication with Herschel-Bulkley model greases. Tribol. Trans. 15, 269–277 (1972)
Smith, F.W.: Lubricant behaviour in concentrated contact systems-some rheological problems. ASLE Trans. 3, 18–25 (1960)
Jacobson, B.O.: An experimental determination of the solidification velocity for mineral oils. ASLE Trans. 17, 290–294 (1974)
Ren, N., Zhu, D., Wen, S.Z.: Experimental method for quantitative analysis of transient EHL. Tribol. Int. 24, 225–230 (1991)
Glovnea, R.P., Diaconescu, E.N., Flamand, L.: EHD film thickness under transient speed conditions. Acta Tribol. 13, 31–36 (1995)
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The work is financially supported by the Natural Science Foundation of China (50721004) and 973 Project (2006CB705403 and 2007CB607604). The authors would like to thank NSK Ltd. for providing the high precision steel balls.
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Li, G., Zhang, C., Xu, H. et al. The Film Behaviors of Grease in Point Contact During Microoscillation. Tribol Lett 38, 259–266 (2010). https://doi.org/10.1007/s11249-010-9602-8
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DOI: https://doi.org/10.1007/s11249-010-9602-8