Vliv kinematických podmínek na tloušťku filmu v mazaném poddajném kontaktu

The effect of kinematic conditions on film thickness in compliant lubricated contact

článek v časopise ve Web of Science, Jimp

en

The present paper deals with an investigation of film formation in compliant lubricated contact. Despite these contacts can be found in many applications of daily life including both biological and technical fields, so far little is known about the lubrication mechanisms inside the contacts. The main attention is paid to the effect of kinematic conditions on central film thickness. For this purpose, fluorescent microscopy method was employed. Experiments were realized in ball-on-disc configuration, while the ball was made from rubber and the disc was from optical glass. The contact was lubricated by glycerol and polyglycol to examine the effect of fluid viscosity. The measurements were conducted under pure rolling and rolling/sliding conditions. The entrainment speed varied from 10 to 400 mm/s and constant load of 0.2 N was applied. Experimental results were compared with two theoretical predictions derived for I-EHL regime. It was found that the thickness of lubricating film gradually increases with increasing entrainment speed, which corresponds to theoretical assumptions. Against expectations, evident influence of slide-to-roll ratio on film formation was observed. In the last part of the paper, some limitations of this study are discussed and several recommendations for further methodology improvement are suggested.

Článek se zabývá studiem formování filmu v mazaném poddajném kontaktu. Navzdory skutečnosti, že se tyto kontakty nachází v mnoha aplikacích každodenního života, a to jak z hlediska biologického, tek technického, doposud nebyly dostatečně objasněny mechanismy mazání těchto kontaktů. Hlavní pozornost je věnována vlivu kinematických podmínek na centrální tloušťku mazacího filmu. Za tímto účelem byla využita metoda na principu fluorescenční mikroskopie. Experimenty byly realizovány v konfiguraci kulička-disk, přičemž kulička byla vyrobena z pryže a disk z optického skla. Kontakt byl mazán glycerolem a polyglykolem při snaze objasnit vliv viskozity maziva. Měření byla realizována za čistého valení, částečného a čistého prokluzu. Byla uvažována unášivá rychlost v rozsahu 10 až 400 mm/s a kontakt byl zatížen konstantní silou o velikosti přibližně 0,2 N. Výsledky experimentů byly porovnány se dvěma teoretickými predikcemi pro i-EHL režim mazání. Bylo zjištěno, že tloušťka filmu postupně narůstá s narůstající unášivou rychlostí, což odpovídá teoretickému předpokladu. Oproti očekáváním byl dále pozorován zřejmý vliv míry prokluzu na formování filmu. V poslední části článku jsou zmíněny určité limitace této studie a je navrženo několik doporučení pro další vývoj použité metodologie.

The present paper deals with an investigation of film formation in compliant lubricated contact. Despite these contacts can be found in many applications of daily life including both biological and technical fields, so far little is known about the lubrication mechanisms inside the contacts. The main attention is paid to the effect of kinematic conditions on central film thickness. For this purpose, fluorescent microscopy method was employed. Experiments were realized in ball-on-disc configuration, while the ball was made from rubber and the disc was from optical glass. The contact was lubricated by glycerol and polyglycol to examine the effect of fluid viscosity. The measurements were conducted under pure rolling and rolling/sliding conditions. The entrainment speed varied from 10 to 400 mm/s and constant load of 0.2 N was applied. Experimental results were compared with two theoretical predictions derived for I-EHL regime. It was found that the thickness of lubricating film gradually increases with increasing entrainment speed, which corresponds to theoretical assumptions. Against expectations, evident influence of slide-to-roll ratio on film formation was observed. In the last part of the paper, some limitations of this study are discussed and several recommendations for further methodology improvement are suggested.

poddajný kontakt, isoviskózní- elastohydrodynamické mazání, tloušťka filmu, fluorescenční mikroskopie, kinematické podmínky

compliant contact; isoviscous-elastohydrodynamic lubrication; film thickness; fluorescence microscopy; kinematic conditions

01.09.2018

The American Society of Mechanical Engineers

USA

0742-4787

140

5

1–8

8