A Review on Grease Lubrication in Rolling Bearings

Lugt, Piet M.

doi:10.1080/10402000802687940

Cited by 297 publications

(207 citation statements)

References 38 publications

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“…9. Literature [40][41][42] suggests that shorter lithium thickener fibres can produce thinner films at low speeds, and consequently higher friction due to increased asperity contacts [43]. Kanazawa et al [22] suggest that the 'transition film thickness' for a given grease, and hence the extent of the region where thickener film enhancement is evident, is determined by the ratio of thickener fibre size to the film thickness obtained by the base oil alone, i.e.…”

Section: Effect Of Base Oil Typementioning

confidence: 99%

The Influence of Base Oil Properties on the Friction Behaviour of Lithium Greases in Rolling/Sliding Concentrated Contacts

et al. 2017

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This study investigates the influence of base oil type and viscosity on the frictional behaviour of lithiumthickened bearing greases. A series of model lithium greases were manufactured by systematically varying viscosity and type of base oil, so that the influence of a single base oil property could be studied in isolation. In addition, selected greases were blended with oleic acid, with the purpose of evaluating its effectiveness in further reducing grease friction. Friction coefficient and film thickness were measured in laboratory ball-on-disc tribometers over a range of speeds and temperatures. For a specific oil type, the influence of base oil viscosity on friction was found to be closely related to its effect on film thickness: greases formulated with PAO oils covering a wide range of viscosities gave very similar friction at the same nominal film thickness. For a given base oil viscosity, base oil type was found to have a strong influence on grease friction under all test conditions. PAO-based greases generally produced lower friction than mineral-and ester-based greases. Addition of oleic acid to the test greases did not significantly affect friction within the range of test conditions employed in this study. The results provide new insight into the frictional behaviour of greases, which may be used to help inform new low-friction grease formulations for rolling bearing applications.

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Section: Effect Of Base Oil Typementioning

confidence: 99%

The Influence of Base Oil Properties on the Friction Behaviour of Lithium Greases in Rolling/Sliding Concentrated Contacts

et al. 2017

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“…Recently, the development of greases has been focused on reduction of torques of rolling element bearings. These efforts seem to be continued and considerable from the fact that greases are used for the lubrication of more than 90% of rolling element bearings [1]. Therefore, understanding the influence of grease components on bearing torques has a significant meaning for the grease development.…”

Section: Introductionmentioning

confidence: 99%

“…One of the main reasons is that the grease shows non-Newtonian behavior [1]. In the initial stage of the bearing operation, the grease is sheared by the moving parts and causes high bearing torque (or temperature increase) due to the drag losses [2,3].…”

Section: Introductionmentioning

confidence: 99%

Influence of Li Grease Thickener Types on Film Thicknesses Formed between Smooth and Dented Surfaces

et al. 2017

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The lubricant film thickness behaviors of lithium (Li) thickener type greases and their base oil were investigated for the contact between a glass disk and a smooth/dented steel ball using an optical interferometry. The main focus is to understand grease film behaviors including high speed history and contact surface conditions. A Li stearate thickened grease showed similar behaviors to the base oil itself and the thickener particles were not observed on the contact. Thickener particle entrainments were observed in greases with Li 12-hydroxy stearate and Li complex thickeners. Track patterns formed in the downstream of the contacts correlated with the thickener particle entrainments to the contacts. The Li stearate thickened grease showed quick starvation phenomenon without a scoop which maintains fully flooded conditions. The particle entrainments of Li 12-hydroxy stearate and Li complex thickened greases were less observed after measurements at high speeds. On the dented surfaces, the particle entrainments of the Li 12-hydroxy stearate grease were more frequent than those of Li complex grease. These results suggest that thickener chemical structures have influence on the grease film formation. The thickener with higher polarity could promote the entrainment of greases into contact.

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“…In fact, microbubbles are formed in grease lubricating film by cavitation [17][18][19][20][21]. Cavitation is defined as the process of nucleation in a liquid when the pressure falls below the vapor pressure [22].…”

Section: Discussionmentioning

confidence: 99%

Microbubble Phenomenon in the Grease Lubricating Film Induced by Micro-Oscillation

Liu

Guo

2013

Tribol Lett

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A microbubble phenomenon induced by microoscillation in the grease lubricating film confined within a nanogap between a highly polished steel ball and a smooth glass disc has been observed with an interferometer. Experimental results show that when the micro-oscillation frequency is a constant value, the microbubble number increases with the micro-oscillation amplitude. When the micro-oscillation amplitude is a constant value, the microbubble number increases with the micro-oscillation frequency when the latter is lower than the critical value and decreases with the micro-oscillation frequency when it is higher than the critical value. Theoretical models and analyses have been used to discuss the bubble formation and describe the characteristics of bubble movement.

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A Review on Grease Lubrication in Rolling Bearings

Cited by 297 publications

References 38 publications

The Influence of Base Oil Properties on the Friction Behaviour of Lithium Greases in Rolling/Sliding Concentrated Contacts

The Influence of Base Oil Properties on the Friction Behaviour of Lithium Greases in Rolling/Sliding Concentrated Contacts

Influence of Li Grease Thickener Types on Film Thicknesses Formed between Smooth and Dented Surfaces

Microbubble Phenomenon in the Grease Lubricating Film Induced by Micro-Oscillation

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