An Experimental Study of Grease-Lubricated Journal Bearings Undergoing Oscillatory Motion

Lu, Xiaobin; Khonsari, M. M.

doi:10.1115/1.2736705

Cited by 9 publications

(1 citation statement)

References 20 publications

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“…Application of grease lubricant is preferred in view of its superior lubrication performance under extreme pressure conditions (Nehme, 2013a(Nehme, , 2013bZhou et al, 2017;De Moerlooze et al, 2011). Compared to oil lubricants, grease offers significant advantages in terms of leakage, load capacity and protection against wear (Zhou et al, 2018;Lu and Khonsari, 2007).…”

Section: Methodsmentioning

confidence: 99%

Effects of Spectrum Loading and break in period using molybdenum disulphide (MoS₂) and zinc dialkyl dithiophosphate (ZDDP) as EP additives in lithium based grease

Nehme,

Nehme

2024

ILT

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Purpose The purpose of variable loading conditions (392 N-785N-392N-785N) with break-in period were used to study interactions between zinc dialkyl dithiophosphate (ZDDP) 0.1 P% (phosphorus) and fine-grade molybdenum disulfide (MoS2) 3%, in different mixtures of NLGI 2 lithium stearate grease. Four-ball wear tests were used to evaluate the tribological properties of different grease mixtures such as coefficient of friction and wear. ASTM 2266 as reported by earlier studies is useful, but it is not representative of real-life applications where variable loads and speeds and different break-in periods play a role and could change the results and the nature of tribofilms. Design/methodology/approach In this study, chemical and mechanical properties of tribofilms were examined. Moreover, design of experiment was used to examine the data and shorten experimentation time. Research described here is investigating variable loading conditions for real-life applications by using a break-in period of 2 min at the start to minimize asperities and establish a clean surface. Design expert (DOE) analyzes responses to reveal those variables that are single factor and those that are multifactor whether synergistically or antagonistically. Findings The results indicated that spectrum loading with break-in period showed reduction in wear when tested in greases with ZDDP/MoS2 combinations. Ramping up or down the load every 7.5 min for a rotational speed of 1,200 rpm and a total of 36,000 revolutions or 30-min time slowed the wear properties of lithium-based grease under different MoS2 and ZDDP concentrations. Experiments indicated that wear was largely dependent on the loading condition and ZDDP additives during specific break-in period at 1,200 rotational speed. It is believed that MoS2 greases perform better under spectrum loading and under constant loading when mixed with ZDDP phosphorus. Originality/value This research indicates that there is a synergistic interaction between ZDDP, MoS2 and variable loading especially when a break-in period is applied. The results indicated that wear was largely dependent on the specific speed used with spectrum loading as presented in the energy dispersive spectroscopy and the Auger electron spectroscopy analysis, and thus a 3% MoS2 grease with ZDDP (phosphorus: 0.1 Wt.%) are needed to improve the wear resistance and improve the friction characteristics. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-01-2024-0016/

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Section: Methodsmentioning

confidence: 99%

Effects of Spectrum Loading and break in period using molybdenum disulphide (MoS₂) and zinc dialkyl dithiophosphate (ZDDP) as EP additives in lithium based grease

Nehme,

Nehme

2024

ILT

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Journal Bearings

2017

Applied Tribology: Bearing Design and Lubrication

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Numerical and experimental study of elastohydrodynamic grease lubrication of dimple textured surfaces

Torabi

Alidousti

2023

Acta Mech

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An Experimental Study of Grease-Lubricated Journal Bearings Undergoing Oscillatory Motion

Cited by 9 publications

References 20 publications

Effects of Spectrum Loading and break in period using molybdenum disulphide (MoS₂) and zinc dialkyl dithiophosphate (ZDDP) as EP additives in lithium based grease

Effects of Spectrum Loading and break in period using molybdenum disulphide (MoS₂) and zinc dialkyl dithiophosphate (ZDDP) as EP additives in lithium based grease

Journal Bearings

Numerical and experimental study of elastohydrodynamic grease lubrication of dimple textured surfaces

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An Experimental Study of Grease-Lubricated Journal Bearings Undergoing Oscillatory Motion

Cited by 9 publications

References 20 publications

Effects of Spectrum Loading and break in period using molybdenum disulphide (MoS2) and zinc dialkyl dithiophosphate (ZDDP) as EP additives in lithium based grease

Effects of Spectrum Loading and break in period using molybdenum disulphide (MoS2) and zinc dialkyl dithiophosphate (ZDDP) as EP additives in lithium based grease

Journal Bearings

Numerical and experimental study of elastohydrodynamic grease lubrication of dimple textured surfaces

Contact Info

Product

Resources

About

Effects of Spectrum Loading and break in period using molybdenum disulphide (MoS₂) and zinc dialkyl dithiophosphate (ZDDP) as EP additives in lithium based grease

Effects of Spectrum Loading and break in period using molybdenum disulphide (MoS₂) and zinc dialkyl dithiophosphate (ZDDP) as EP additives in lithium based grease