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Novel In-Situ Observation of the Grease Constituents in Elastohydrodynamic Contacts by Fluorescence Microscopy

  • Tribology Methods
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Abstract

Grease is important lubricant for ball bearings as it is used much more often than oil. However, mechanism of the lubrication is not completely clear, especially concerning the role of the thickener in the lubricating process. It was shown that contribution of the thickener to film thickness build-up varies with operating conditions. Also, its influence on the resistive torque of the bearing was proved. However, all studies were in-direct showing its effects. This paper presents new in-situ fluorescence method of the grease constituents’ observation, where both, thickener, and base oil can be observed independently. Two different fluorescence dyes are used to distinguish grease constituents with the use of different microscope setup. Moreover, the new method was tested on two different test rigs. First is typical ball on disc test rig widely used for study of elastohydrodynamic lubrication. Second is ball on ring test rig which more closely represents radial ball bearing conditions. It was shown that thickener engagement is very different for each geometrical configuration.

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References

  1. Gohar, R., Cameron, A.: Optical measurement of oil film thickness under elastohydrodynamic lubrication. Nature. 200, 458–459 (1963)

    Article  Google Scholar 

  2. Wedeven, L., Evans, D., Cameron, A.: Optical analysis of ball bearing starvation. J. Tribol. 1, 349–363 (1971)

    Google Scholar 

  3. Kostal, D., Necas, D., Sperka, P., Svoboda, P., Krupka, I., Hartl, M.: Lubricant rupture ratio at elastohydrodynamically lubricated contact outlet. Tribol. Lett. (2015). https://doi.org/10.1007/s11249-015-0565-7

    Article  Google Scholar 

  4. Cann, P.: Starvation and reflow in a grease-lubricated elastohydrodynamic contact. Tribol. Trans. 39, 698–704 (1996). https://doi.org/10.1080/10402009608983585

    Article  CAS  Google Scholar 

  5. Huang, L., Guo, D., Shizhu, W.: Film thickness decay and replenishment in point contact lubricated with different greases: a study into oil bleeding and the evolution of lubricant reservoir. Tribol. Int. 93, 620–627 (2016)

    Article  Google Scholar 

  6. Fischer, D., Jacobs, G., Stratmann, A., Burghardt, G.: Effect of base oil type in grease composition on the lubricating film formation in EHD contacts. Lubricants. 6, 32 (2018). https://doi.org/10.3390/lubricants6020032

    Article  Google Scholar 

  7. Hartl, M., Krupka, I., Poliscuk, R., Liska, M., Molimard, J., Querry, M., Vergne, P.: Thin film colorimetric interferometry. Tribol. Trans. 44, 270–276 (2001). https://doi.org/10.1080/10402000108982458

    Article  CAS  Google Scholar 

  8. Sperka, P., Křupka, I., Hartl, M.: Experimental study of real roughness attenuation in concentrated contacts. Tribol. Int. 43, 1893–1901 (2010)

    Article  CAS  Google Scholar 

  9. Svoboda, P., Kostal, D., Krupka, I., Hartl, M.: Experimental study of starved EHL contacts based on thickness of oil layer in the contact inlet. Tribol. Int. 67, 140–145 (2013). https://doi.org/10.1016/j.triboint.2013.07.019

    Article  Google Scholar 

  10. Kostal, D., Sperka, P., Krupka, I., Hartl, M.: Experimental comparison of the behavior between base oil and grease starvation based on inlet film thickness. Tribol. Ind. 39, 110–119 (2017). https://doi.org/10.24874/ti.2017.39.01.12

    Article  Google Scholar 

  11. Smart, A., Ford, R.: Measurement of thin liquid films by a fluorescence technique. Wear 29, 41–47 (1974). https://doi.org/10.1016/0043-1648(74)90132-X

    Article  Google Scholar 

  12. Sugimura, J., Hashimoto, M., Yamamoto, Y.: Study of elastohydrodynamic contacts with fluorescence microscope. Thinning Films and Tribological Interfaces, Proceedings of the 26th Leeds-Lyon Symposium on Tribology. (2000). https://doi.org/10.1016/S0167-8922(00)80165-0

    Article  Google Scholar 

  13. Azushima, A.: In lubro 3D measurement of oil film thickness at the interface between tool and workpiece in sheet drawing using a fluorescence microscope. Tribol. Int. 38, 105–112 (2005). https://doi.org/10.1016/j.triboint.2004.04.006

    Article  Google Scholar 

  14. Chen, H., Wang, W., Liang, H., Ge, X.: Observation of the oil flow in a ball bearing with a novel experiment method and simulation. Tribol. Int. 174, 107731 (2022). https://doi.org/10.1016/j.triboint.2022.107731

    Article  Google Scholar 

  15. Chennaoui, M., Fowell, M., Liang, H., Kadiric, A.: A novel set-up for in situ measurement and mapping of lubricant film thickness in a model rolling bearing using interferometry and ratiometric fluorescence imaging. Tribol. Lett. (2022). https://doi.org/10.1007/s11249-022-01625-z

    Article  Google Scholar 

  16. Liang, H., Zhang, Y., Wang, W., Zhang, S.: An experimental study on the distribution and migration of lubricating oil in rolling bearings at low speeds. Tribol. Trans. 65, 677–685 (2022). https://doi.org/10.1080/10402004.2022.2069627

    Article  CAS  Google Scholar 

  17. Liang, H., Zhang, Y., Wang, W.: Influence of the cage on the migration and distribution of lubricating oil inside a ball bearing. Friction. 10, 1035–1045 (2022). https://doi.org/10.1007/s40544-021-0510-8

    Article  CAS  Google Scholar 

  18. Cen, H., Lugt, P., Morales-Espejel, G.: On the film thickness of grease-lubricated contacts at low speeds. Tribol. Trans. 57, 668–678 (2014). https://doi.org/10.1080/10402004.2014.897781

    Article  CAS  Google Scholar 

  19. Lugt, P., Morales-Espejel, G.: A review of elasto-hydrodynamic lubrication theory. Tribol. Trans. 54, 470–496 (2011). https://doi.org/10.1080/10402004.2010.551804

    Article  Google Scholar 

  20. Lugt, P.: Modern advancements in lubricating grease technology. Tribol. Int. 2016, 467–477 (2016)

    Article  Google Scholar 

  21. Cen, H., Lugt, P.: Replenishment of the EHL contacts in a grease lubricated ball bearing. Tribol. Int.. 146, 106064 (2020). https://doi.org/10.1016/j.triboint.2019.106064

    Article  Google Scholar 

  22. Cen, H., Lugt, P.: Effect of start-stop motion on contact replenishment in a grease lubricated deep groove ball bearing. Tribol. Int. 157, 106882 (2021). https://doi.org/10.1016/j.triboint.2021.106882

    Article  Google Scholar 

  23. Fischer, D., von Goeldel, S., Jacobs, G., Stratmann, A.: Numerical investigation of effects on replenishment in rolling point contacts using CFD simulations. Tribol. Int.. 157, 106858 (2021). https://doi.org/10.1016/j.triboint.2021.106858

    Article  Google Scholar 

  24. Chen, H., Liang, H., Wang, W., Zhang, S.: Investigation on the oil transfer behaviors and the air-oil interfacial flow patterns in a ball bearing under different capillary conditions. Friction. (2022). https://doi.org/10.1007/s40544-021-0592-3

    Article  Google Scholar 

  25. Chen, H., Wang, W., Zhao, Z., Liang, H.: Evolution and flow maps of the oil layer in successive rolling point contact systems: bearing as a case. Phys Fluids. 34, 032110 (2022). https://doi.org/10.1063/5.0084464

    Article  CAS  Google Scholar 

  26. Liang, H., Guo, D., Ma, L., Luo, J.: Experimental investigation of centrifugal effects on lubricant replenishment in the starved regime at high speeds. Tribol. Lett. (2015). https://doi.org/10.1007/s11249-015-0526-1

    Article  Google Scholar 

  27. Liang, H., Fan, Z., Wang, W., Zhao, Z.: Experimental investigation of the oil supply layer in a model rolling bearing. J Tribol. (2023). https://doi.org/10.1115/1.4055719

    Article  Google Scholar 

  28. Sakai, K., Kostal, D., Shitara, Y., Kaneta, M., Krupka, I., Hartl, M.: Influence of Li Grease thickener types on film thicknesses formed between smooth and dented surfaces. Tribol. Online. 12, 262–273 (2017). https://doi.org/10.2474/trol.12.262

    Article  Google Scholar 

  29. Sakai, K., Tokumo, Y., Ayame, Y., Shitara, Y., Tanaka, H., Sugimura, J.: Effect of formulation of Li Greases on their flow and ball bearing torque. Tribol. Online. 11, 168–173 (2016). https://doi.org/10.2474/trol.11.168

    Article  Google Scholar 

  30. Cyriac, F., Lugt, P., Bosman, R., Padberg, C., Venner, C.: Effect of thickener particle geometry and concentration on the grease EHL film thickness at medium speeds. Tribol. Lett. (2016). https://doi.org/10.1007/s11249-015-0633-z

    Article  Google Scholar 

  31. Kostal, D., Onitsuka, S., Tanaka, H., Sugimura, J., Krupka, I., Hartl, M.: Use of pyrene for quantitative fluorescence observation of Li-Grease around EHL contacts. Tribol. Online. 15, 117–125 (2020). https://doi.org/10.2474/trol.15.117

    Article  Google Scholar 

  32. Thielicke, W., Sonntag, R.: Particle image velocimetry for MATLAB: accuracy and enhanced algorithms in PIVlab. J. Open Res. Softw. 9, 1–14 (2021). https://doi.org/10.5334/jors.334

    Article  Google Scholar 

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Acknowledgements

Authors would like to thank Kazumi Sakai for kind sample preparation.

Funding

This research was carried out under the project FSI-S-20-6443 with financial support from the Ministry of Education, Youth and Sports of the Czech Republic.

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Authors and Affiliations

  1. Faculty of Mechanical Engineering, Brno University of Technology, Brno-střed, Czechia

    David Kostal, Michal Okal, Josef Fryza, Ivan Krupka & Martin Hartl

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  1. David Kostal
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  2. Michal Okal
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  3. Josef Fryza
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  4. Ivan Krupka
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  5. Martin Hartl
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Contributions

All authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by DK, MO and JF. The first draft of the manuscript was written by DK and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript.

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Correspondence to David Kostal.

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Kostal, D., Okal, M., Fryza, J. et al. Novel In-Situ Observation of the Grease Constituents in Elastohydrodynamic Contacts by Fluorescence Microscopy. Tribol Lett 70, 126 (2022). https://doi.org/10.1007/s11249-022-01671-7

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