Traction curves and rheological parameters of fully formulated gear oils

Brandão, José A.; Meheux, M.; Seabra, Jorge; Ville, Fabrice; Castro, J.

doi:10.1177/1350650111405111

Cited by 34 publications

(21 citation statements)

References 21 publications

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“…We can observe that a mineral base oil has higher friction coefficient (μ EHD ) than a synthetic oil or than a mineral with a viscosity modifier additive in large concentration, as the case of MINE oil. The friction behaviour of the PAO (PAOR) and of the ester (ESTR) are very similar, which has already been reported by Brandão [35]. The traction coefficient decreases with the increasing temperature and decreases with the increasing speed which is coherent with the literature [35].…”

Section: Resultssupporting

confidence: 82%

“…It can be observed that for all lubricating oils, the increase of temperature decreases the coefficient of friction. Such behaviour is expected for full film lubrication conditions, as suggested in literature [35].…”

Section: Traction Coefficientmentioning

confidence: 70%

“…However, MINR traction coefficient is higher than the other oils. So, the base oil is the most important factor for the traction coefficient [35].…”

Section: Traction Coefficientmentioning

confidence: 99%

“…The coefficients of friction are presented using the modified Hersey number suggested by Brandão [35] and given by equation (10). The original…”

Section: Stribeck Curvementioning

confidence: 99%

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Film thickness and traction curves of wind turbine gear oils

Fernandes

Marques

Martins

et al. 2015

Tribology International

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Section: Resultssupporting

confidence: 82%

Section: Traction Coefficientmentioning

confidence: 70%

“…However, MINR traction coefficient is higher than the other oils. So, the base oil is the most important factor for the traction coefficient [35].…”

Section: Traction Coefficientmentioning

confidence: 99%

“…The coefficients of friction are presented using the modified Hersey number suggested by Brandão [35] and given by equation (10). The original…”

Section: Stribeck Curvementioning

confidence: 99%

See 2 more Smart Citations

Film thickness and traction curves of wind turbine gear oils

Fernandes

Marques

Martins

et al. 2015

Tribology International

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“…Comparing the different grease formulations, it is clear that synthetic base oils of lower viscosity promote low friction greases, as observed before in other works related to oil and grease lubrication [9,10,21,22,31]. Of course that, a lower viscosity base oil will also generate a lower film thickness for the same operating conditions which might not be desirable.…”

Section: Discussionsupporting

confidence: 49%

Film Thickness and Friction Relationship in Grease Lubricated Rough Contacts

et al. 2017

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Abstract:The relationship between the film generation and the coefficient of friction in grease lubricated contacts was investigated. Ball-on-disc tests were performed under different operating conditions: entrainment speed, lubricant temperature and surface roughness. The tests were performed with fully formulated greases and their base oils. The greases were formulated with different thickener types and also different base oils natures and viscosities. Film thickness measurements were performed in ball-on-glass disc tests, and Stribeck curves were measured in ball-on-steel disc tests with discs of different roughness. The role of the thickener and the base oil nature/viscosity on the film thickness and coefficient of friction was addressed and the greases' performance was compared based on their formulation.

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Coefficient of friction behavior of gear oils and significance for the meshing process of spur gears

Baumann

Bertsche

2022

Forsch Ingenieurwes

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The mechanical properties of oils are determined using test methods. There are standardized test methods for determining viscosity and density. The characterization of transmission oil based on its dynamic viscosity alone is not sufficient for the physical explanation of different levels of noise emissions in vehicle transmissions. For this reason, the test procedure for determining the coefficient of friction is used in the following to enable a further differentiation between the oils according to mechanical properties.In gear transmissions with involute gear teeth, rolling friction occurs in the gear pair meshing along the line of action due to the variation in the equivalent curvature radii throughout the meshing cycle. This is rolling friction on which a sliding friction component, so-called slip, is superimposed. Pure rolling friction only occurs in the pitch point. From the pitch point to the start and end of the meshing, there is a superimposed sliding friction component that increases with increasing distance from the pitch point. Slip values occur in the range of 5–50% depending on tooth geometry.These friction conditions during tooth flank lubrication can be assessed using the Stribeck curve. The Stribeck curve represents the coefficient of friction as a function of the speed. A mini traction machine from PCS Instruments with a ball/plate measurement setup was used to determine the coefficient of friction behavior of gear oils. This allows the coefficient of friction of an oil to be assessed at low speeds in the range from boundary and mixed friction to elastohydrodynamic fluid friction at high speeds.The investigations show that the coefficient of friction behavior of a gear oil depends on the oil viscosity and above all on the chemical composition. The lower the coefficient of friction, the less energy is required to shear the lubricating film and the lower the power transmission through the fluid. The coefficient of friction is a property that is dominated by the type of base oil and the type of VI improver in the area of mixed and fluid friction, especially with additional sliding in contact.It will be shown in the paper that the use of a gear oil that has been optimized with regard to the coefficient of friction curve can reduce the entry impacts of meshing gear pairs under vibration excitation and the gear transmission thus generates lower noise emissions.

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Traction curves and rheological parameters of fully formulated gear oils

Cited by 34 publications

References 21 publications

Film thickness and traction curves of wind turbine gear oils

Film thickness and traction curves of wind turbine gear oils

Film Thickness and Friction Relationship in Grease Lubricated Rough Contacts

Coefficient of friction behavior of gear oils and significance for the meshing process of spur gears

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