Stability analysis of long hydrodynamic journal bearings based on the journal center trajectory

Abstract

In this study, we observe that there are two threshold speeds (stability threshold speed and second threshold speed) for the long journal bearing, which is different for the short bearing. When the rotating speed is below the stability threshold speed, the stability boundary nearly coincides with the clearance circle, and the journal center gradually returns to the equilibrium point after being released at an initial point. If the rotating speed is between the stability threshold speed and the second threshold speed, after being released at an initial point, the journal center converges to a contour containing the equilibrium point. In this situation, for a higher rotating speed, the corresponding contour is also larger. When the rotating speed exceeds the second threshold speed, the journal gradually moves towards the bearing surface after being released at an initial point.

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Acknowledgements

This research is supported by doctoral research fund of Hubei University of Arts and Science (No. 2059023), the Project of Hubei University of Arts and Science (No. XK2020005), National Science and Technology Major Project (No. 2019ZX04001024), Central Government Guides Local Science and Technology Development Projects of Hubei Province (No. 2018ZYYD016), and start-up program for excellent young and middle-aged scientific and technological innovation team of Hubei Provincial Department of Education (No. T201919).

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Correspondence to Zhuxin Tian.

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Yu HUANG. He received his bachelor degree in machinery manufacturing process and equipment in 1993 from Huazhong University of Science and Technology, Wuhan, China. He received his M.S. and Ph.D. degrees in automotive engineering and mechanical design manufacturing and automation from Huazhong University of Science and Technology in 2000 and 2004 respectively. Then, he joined Huazhong University of Science and Technology as a lecturer. His current position is a professor and the deputy director of the National Engineering Research Center for Digitalization of Manufacturing Equipment. His research areas cover high performance hydrostatic bearing, laser fine processing technology and equipment, and high-power laser cutting and welding equipment.

Zhuxin TIAN. He received his bachelor degree in mechanical design manufacturing and automation in 2009 from Huazhong University of Science and Technology, Wuhan, China. He has obtained his Ph.D. degree in mechatronic engineering from Huazhong University of Science and Technology in 2018. Then, he joined Hubei University of Arts and Science as a lecturer. His research interests include hydrostatic and hydrodynamic bearings.

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Huang, Y., Cao, H. & Tian, Z. Stability analysis of long hydrodynamic journal bearings based on the journal center trajectory. Friction (2020). https://doi.org/10.1007/s40544-020-0448-2

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Keywords

  • long journal bearings
  • stability threshold speed
  • stability boundary
  • journal center trajectory