Behaviour of polymer-thickened oils in lubricated concentrated contacts

Yoshida, Kazuo; Hosonuma, Kunihiko; Sakurai, Takeshi

doi:10.1016/0043-1648(84)90217-5

Cited by 18 publications

(4 citation statements)

References 14 publications

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“…As described in Ref. (7), the smaller the PMA G, the thicker the EHD film formed. T h e influence of additive concentration on EHD film forming capability is such that the higher the concentration, the thicker the oil film.…”

Section: Discussionmentioning

confidence: 92%

“…Polynler-thickened oils form thinner EHD films when compared with straight oils having the same low shear viscosity (2)- (7). This inferiority has been explained by temporary and permanent viscosity loss (2)-(4).…”

Section: Introductionmentioning

confidence: 98%

“…(6). However, this explanation may not apply necessarily to concentrated contacts as indicated by measurements o f EHD film thickness (7), and friction and wear experiments (8)- (10). T h e friction and wear experiments were conducted with some oils containing polymethacrylate (PMA), a representative viscosity index improver.…”

Section: Introductionmentioning

confidence: 99%

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Effects of Average Molecular Weight and Concentration of Polymer Additive on Friction and Wear

Yoshida

1990

Tribology Transactions

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Tribologzcal belzavior with oils containing PMAs differing inaverage molecular weight, Mw, is examined in sliding concentmted -cont~~c1S. At low loccds, low PMA Mw or higher concentrations of PMA have a beneficial effect on wear, but at high loads are detrimental. The beneficial effect is attributed to EHD film formation. The most important parameter is the number of PMA molecules per unit oil volzcme. The prowear action can be explained by the fkct that PMA molecules may accumulate in the inlet region of the contact. T l~e polymer accumuk~tion may block the bme oil entering the contact leuding to oil staruation which in turn leads to severe contacLq and incre~.~e.~ in wear. This a n a m l o w behavior may result from the competition between the prowear action and oil film formation.

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Section: Discussionmentioning

confidence: 92%

Section: Introductionmentioning

confidence: 98%

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Effects of Average Molecular Weight and Concentration of Polymer Additive on Friction and Wear

Yoshida

1990

Tribology Transactions

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“…So far, a number of studies on film-forming properties of polymer solutions have been reported [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. It has been well known that under high rolling speeds, in thick film regions, HMw polymer solutions show thinner films than the estimated results from the EHL theory [5][6][7][8][9][10][11][12][13][14][15][16][17]. Bair et al explained that the shear thinning was brought about by shearing a polymer molecule at the contact inlet [21][22][23][24][25][26][27][28].…”

Section: Introductionmentioning

confidence: 99%

Film-forming properties and traction of non- functionalized polyalkylmethacrylate solutions under transition from elastohydrodynamic lubrication to thin-film lubrication

Muraki

Nakamura

2009

Proceedings of the Institution of Mechanical Engineers, Part J:

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Oil film thickness of the oils containing non-functionalized polyalkylmethacrylate (PAMA) was determined under pure rolling condition between 0.001 and 1 m/s and a temperature of 40 • C with a glass disc-on-steel roller tester. The measurements for PAMA solutions with shortchain alkyl group (C1mix) showed a pronounced enhancement of film thickness in the low speeds, while those for long chain (C16mix) fell on the theoretical line. Adsorption test indicated that the increase in film thickness for C1mix was due to the absorbed layer formed by polymer molecule. Then, traction behaviour was studied by varying the rolling speed under a slide/roll ratio of 50 per cent with a sapphire disc-on-steel roller tester. In traction-speed curves, the measurements of all the polymer solutions fell on the base oil line in the high speeds. In the region below 0.1 m/s, as the speed was decreased, the traction for high-molecular-weight (HMw) C1mix and C16mix solutions deviated downward from the base oil line. The traction-film parameter curves suggested that the traction for C1mix and HMw-C1mix solutions was influenced by the mutual interaction of polymer molecules in the partial EHL region including thin-film lubrication, where the concentration of the polymer is high compared to bulk solution.

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Lubricant oils additivated with polymers in EHD contacts: Part 1. Rheological behaviour

Bercea¹,

Paleu

Bercea

2004

Lubrication Science

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This paper reports on the influence of a polymer additive on the traction behaviour of a mineral oil investigated using a twodisc machine at different temperatures and contact pressures. A semi-empirical approach was used for determining the effective lubricant rheological parameters -the elasiic shear modulus, the viscosity of the lubricant, and the 1im.iting and Eyring stresses -in elastohydrodynamic contacts. Using this approach, the effect of polymer concentration on the rheological parameters that appear in both the Johnson-Tevaarwerk and Bair-Winer models was quantified. The influence of operating conditions, such as pressure, oil temperature, and polymer concentration, on the traction coefficient, limiting shear stress (from the Bair-Winer model), Eyring stress (from the JohnsonTeuaarwerk model), shear modulus, and apparent viscosity was also investigated. Nomenclature a b B" B-W E E' G G, hcen J-T N half-width of an elliptical contact in the transverse direction, m half-width of an elliptical contact iit the rolling direction, m slope of traction curve in the linear region Bair-Winer rheological model elastic component equivalent elastic modulus of contact bodies, N/m2 elastic shear modulus of lubricant, IUm2 dimensionless material parameter =: aE' thermally central film thickness, m Johnson-Tevaarwerk rheological m.)del normal load contact, N

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Behaviour of polymer-thickened oils in lubricated concentrated contacts

Cited by 18 publications

References 14 publications

Effects of Average Molecular Weight and Concentration of Polymer Additive on Friction and Wear

Effects of Average Molecular Weight and Concentration of Polymer Additive on Friction and Wear

Film-forming properties and traction of non- functionalized polyalkylmethacrylate solutions under transition from elastohydrodynamic lubrication to thin-film lubrication

Lubricant oils additivated with polymers in EHD contacts: Part 1. Rheological behaviour

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