The Relative Thickness of Grease and Oil Films in Rolling Bearings

Wilson, Andrew

doi:10.1243/pime_proc_1979_193_019_02

Cited by 75 publications

(42 citation statements)

References 6 publications

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“…Wilson [1] observed this phenomenon in a rolling bearing in 1979. Zhu and Neng [2] then measured the large decrease of film thickness in a starved grease lubricated point contact.…”

Section: Introductionmentioning

confidence: 89%

Film thickness decay and replenishment in point contact lubricated with different greases: A study into oil bleeding and the evolution of lubricant reservoir

Huang

Guo

Wen

2016

Tribology International

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“…Wilson [1] observed this phenomenon in a rolling bearing in 1979. Zhu and Neng [2] then measured the large decrease of film thickness in a starved grease lubricated point contact.…”

Section: Introductionmentioning

confidence: 89%

Film thickness decay and replenishment in point contact lubricated with different greases: A study into oil bleeding and the evolution of lubricant reservoir

Huang

Guo

Wen

2016

Tribology International

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“…Other experimental studies with lubricating greases may be found in [6][7][8][9][10]. All these research works suggest the same grease film formation mechanism: initially grease builds-up a higher film thickness than its base oil, but it decreases with time and reaches a starved condition.…”

Section: Introductionmentioning

confidence: 96%

Film thickness in a ball-on-disc contact lubricated with greases, bleed oils and base oils

Cousseau

Björling

Graça

et al. 2012

Tribology International

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Three different lubricating greases and their bleed and base oils were compared in terms of film thickness in a ball-on-disc test rig through optical interferometry. The theoretical values calculated according to Hamrock's equation are in close agreement with the base oil film thickness measurements, which validates the selected experimental methodology.The grease and bleed oil film thickness under fully flooded lubrication conditions presented quite similar behaviour and levels. Therefore, the grease film thickness under full film conditions might be predicted using their bleed oil properties, namely the viscosity and pressure-viscosity coefficient. The base and bleed oil lubricant parameter LP are proportional to the measured film thickness.A relationship between grease and the corresponding bleed oil film thickness was evidenced.

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“…By definition according to Wilson [23], the onset of starvation occurs at the above described characteristic rolling speed. This study focuses on measurements under starved grease lubrication and the onset of starvation will be pointed out by following the definition by Wilson [23].…”

Section: Introductionmentioning

confidence: 99%

Effect of Base Oil Type in Grease Composition on the Lubricating Film Formation in EHD Contacts

et al. 2018

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The service life of rolling bearings is significantly affected by the film formation in elastohydrodynamic (EHD) contacts, which depends on the operating conditions, like rotational speed or temperature. In grease lubricated EHD contacts, the film formation is determined by the grease consistency and composition, i.e., thickener and base oil type as well as properties of the bleed oil, which is released from the grease during operation. Thus, the film formation of grease lubricated contacts as compared to base oil lubricated contacts can be different. With increasing rolling speed, the film thickness of oil lubricated contacts usually grows. However, in case of grease lubricated contacts, which are not fully flooded, the film thickness remains constant or even decreases with further increasing rotational speed. This effect is referred to as starvation. Since the onset of starvation depends on the grease composition, the film formation of two different grease compositions is investigated in this study. The film thickness measurements are performed on a ball-on-disc tribometer for each grease, as well as the corresponding bleed and pure base oils. Thereby, the characteristic rotational speed leading to the onset of starvation has been identified in dependence of the grease composition and the differences in the lubricating film formation of base oil, bleed oil, and grease lubricated EHD contacts have been discussed. The investigations should help to establish an advanced understanding of the physical mechanisms leading to the onset of starvation to encourage future work with focus on a method to predict the film formation in grease lubricated EHD contacts.

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The Relative Thickness of Grease and Oil Films in Rolling Bearings

Cited by 75 publications

References 6 publications

Film thickness decay and replenishment in point contact lubricated with different greases: A study into oil bleeding and the evolution of lubricant reservoir

Film thickness decay and replenishment in point contact lubricated with different greases: A study into oil bleeding and the evolution of lubricant reservoir

Film thickness in a ball-on-disc contact lubricated with greases, bleed oils and base oils

Effect of Base Oil Type in Grease Composition on the Lubricating Film Formation in EHD Contacts

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