Abstract
For high-speed, heavy-load gear units, the meshing tooth surfaces are generally under the mixed lubrication state, which is crucial for gear pitting or micro pitting damage. To clarify the effects of lubrication state on tooth pitting damage, carrying out both numerical and experimental studies on the contact severity of gears under different lubrication states is necessary. In this paper, a 3D line-contact elasto hydrodynamic lubrication model considering fractal surface roughness was developed and used to investigate the lubrication characteristics of involute gears. Both the distributions of pressure and film thickness fluctuated under the rolling contact of rough surfaces. The fluctuations became more substantial with the increase of load and roughness. Furthermore, from the calculated film thickness ratio λ, the contact of gear tooth surfaces with a fractal roughness of Ra = 0.8 µm was always under full lubrication state (λ > 1). When the roughness was increased to Ra = 3.2 µm, the contact was first transmitted into the mixed lubrication state (0.2 < λ < 1) under the load of 1000 N*m and finally deteriorated to boundary lubrication state (λ < 0.2) under the load of 2000 N*m. The boundary lubrication state that occurred under the contact of highly rough surfaces could induce the formation of gear pitting damage. The contact fatigue test showed the gear tooth surface roughness increased from 0.7 µm to around 2.7 µm after 8 million running cycles and then suffered pitting failure after another 2 million cycles, which was consistent with the simulation analysis prediction.
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References
J. Wei, A. Q. Zhang and P. Gao, A study of spur gear pitting under EHL conditions: theoretical analysis and experiments, Tribology International, 94 (2016) 146–154.
J. Ji et al., Prediction of stress concentration factor of corrosion pits on buried pipes by least squares support vector machine, Engineering Failure Analysis, 55 (2015) 131–138.
D. Zhu and Q. J. Wang, Elastohydrodynamic lubrication (EHL): a gateway to interfacial mechanics review and prospect, Journal of Tribology, 133 (4) (2011) 041001–1–14.
W. Tuszynski, An effect of lubricating additives on tribochemical phenomena in a rolling steel four-ball contact, Tribology Letters, 24 (3) (2006) 207–215.
P. Kumar, P. Anuradha and M. M. Khonsari, Some important aspects of thermal elastohydrodynamic lubrication, Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, 224 (12) (2010) 2588–2598.
T. Ahlroos et al., Twin disc micropitting tests, Tribology International, 42 (10) (2009) 1460–1466.
M. Masjedi and M. M. Khonsari, On the effect of surface roughness in point-contact EHL: formulas for film thickness and asperity load, Tribology International, 82 (2015) 228–244.
A. V. Olver and D. Dini, Roughness in lubricated rolling contact: the dry contact limit, Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology, 221 (7) (2007) 787–791.
S. Li and A. Kahraman, A transient mixed elastohydrodynamic lubrication model for spur gear pairs, Journal of Tribology, 132 (1) (2010) 011501–1–9.
Z. Liu, 3D transient line-contact EHL modeling of involute spur gear, Master Thesis, Chongqing University, China (2014).
X. Shi et al., Three-dimensional mixed lubrication analysis of spur gears with machined roughness, Tribology International, 140 (2019) 105864.
S. Sjöberg, S. Björklund and U. Olofsson, The Influence of manufacturingmethod on the running-in of gears, Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology, 225 (10) (2011) 999–1012.
T. Nakanishi, Y. Ariura and T. Ueno, Load-carrying capacity of surface hardened gears: influence of surface roughness on surface durability: vibration, Control Engineering, Engineering for Industry, JSME International Journal, 30 (259) (1987) 161–167.
ISO/TR15144-1, Calculation of Micropitting Load Capacity of Cylindrical Spur and Helical Gears — Part 1: Introduction and Basic Principles, International Organization for Standardization (2014).
J. Q. Li et al., Competitive failure mechanism of micro-pitting and thermal-scuffing in gear transmission, Tribology, 41 (5) (2021) 636–646.
H. P. Evans et al., Analysis of micro elastohydrodynamic lubrication and prediction of surface fatigue damage in micro-pitting tests on helical gears, Journal of Tribology, 135 (1) (2013) 011501.
S. Z. Wen and P. Huang, Principles of Tribology, Fourth Edition, Tsinghua University Press, Beijing (2012).
H. X. Li, Point-Line Meshing Gear Transmission, China Machine Press, Beijing (2011).
M. B. Sanchez, M. Pleguezuelos and J. I. Pedrero, Approximate equations for the meshing stiffness and the load sharing ratio of spur gears including Hertzian effects, Mechanism and Machine Theory, 109 (2017) 231–249.
W. J. Pan, X. P. Li and X. Wang, Contact mechanics of elastic-plastic fractal surfaces and static friction analysis of asperity scale, Engineering Computations, 38 (1) (2020) 131–150.
Q. Chen, Research on gear contact strength analysis of automobile gearbox by fractal theory, Master Thesis, Hefei University of Technology, China (2010).
S. R. Ge and H. Zhu, Fractal Tribology, China Machine Press, Beijing (2005).
AGMA 925-A03, Effect of Lubrication on Gear Surface Distress, American Gear Manufacturers Association (2003).
M. Y. Liu, Research on thermal finite line contact EHL for helical gears, Master Thesis, Chongqing University, China (2013).
X. P. Wang, Research on dynamic characteristics of gear transmission system under fatigue pitting of tooth surface, Ph.D Thesis, China Academy of Machinery Science and Technology, China (2020).
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The work was supported by the National Natural Science Foundation of China (Number 51775516).
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Youhua Li is an Associate Professor at the School of Mechatronics Engineering, Zhongyuan University of Technology. She received her Ph.D. in the Zhengzhou Research Institute of Mechanical Engineering. Her research interests include mechanical transmission, gear transmission technology research, and friction lubrication.
Xiaopeng Wang is an Associate Professor at the School of Aeronautical Engineering, Zhengzhou University of Aeronautics. He received his Ph.D. in the Zhengzhou Research Institute of Mechanical Engineering. His research interests include mechanical transmission, gear transmission technology research, and friction lubrication.
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Li, Y., Shi, L., Liu, Z. et al. Study on the lubrication state and pitting damage of spur gear using a 3D mixed EHL model with fractal surface roughness. J Mech Sci Technol 36, 5947–5957 (2022). https://doi.org/10.1007/s12206-022-1111-9
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DOI: https://doi.org/10.1007/s12206-022-1111-9