Experimentální pozorování doplňování maziva v elastohydrodynamicky mazaných kontaktech

Experimental observation of elastohydrodynamically lubricated contacts replenishment

journal article in Scopus

en

Starved regime of elastohydrodynamic lubrication (EHL) is usually described by smaller thicknesses of the lubrication film then fully flooded regime. This state can be caused by a number of reasons including operating conditions, lubricant supply or/and its properties. Rolling bearings contain multiple consequent elements which can increase the risk of starvation because the replenishment mechanisms are not able to recover lubricant film after each element passage. One of the main aspects in the rolling bearings is proximity of the rolling elements. Severity of the starvation increases as the mutual elements distance decreases. Lubricant which was squeezed out by rolling element need some time to replenish the gap. This paper presents experimental methods for measuring the time necessary for oil lubricant film recovery. Results obtained by these methods had been compared with existing theory. The theory describes behavior of replenishment of the central film thickness and change in the lubricant distribution across the rolling track. Both of these aspects qualitatively agree. Changes in the central film thickness during replenishment process were theoretically described as very nonlinear process which was confirmed by experiment in this paper.

Hladovějící režim elastohydrodynamického mazání (EHL) je obvykle popisován menšími tloušťkami mazacího filmu než plně zaplavený režim. Tento stav může být způsoben řadou důvodů, včetně provozních podmínek, dodávky maziva, nebo / a jeho vlastností. Valivá ložiska obsahují více valivých elementů v jedné řadě, což může zvýšit riziko hladovění, protože doplňovací mechanismy nejsou schopny obnovit mazací film po každém průchodu elementu. Jedním z hlavních parametrů z tohto pohledu ve valivých ložiskách je blízkost valivých prvků. Závažnost hladovění se zvyšuje, jestliže se vzájemná vzdálenost mezi elementy snižuje. Tento článek prezentuje experimentální metodu pro měření času potřebného pro obnovu mazacího filmu. Výsledky získané podle těchto metod, byly ve srovnány se stávajícími teoriemi. Změny v centrální tloušťce filmu během procesu doplňování byly teoreticky popsány jako velmi nelineární proces, ktery byl potvrzen experimentem v tomto článku.

Starved regime of elastohydrodynamic lubrication (EHL) is usually described by smaller thicknesses of the lubrication film then fully flooded regime. This state can be caused by a number of reasons including operating conditions, lubricant supply or/and its properties. Rolling bearings contain multiple consequent elements which can increase the risk of starvation because the replenishment mechanisms are not able to recover lubricant film after each element passage. One of the main aspects in the rolling bearings is proximity of the rolling elements. Severity of the starvation increases as the mutual elements distance decreases. Lubricant which was squeezed out by rolling element need some time to replenish the gap. This paper presents experimental methods for measuring the time necessary for oil lubricant film recovery. Results obtained by these methods had been compared with existing theory. The theory describes behavior of replenishment of the central film thickness and change in the lubricant distribution across the rolling track. Both of these aspects qualitatively agree. Changes in the central film thickness during replenishment process were theoretically described as very nonlinear process which was confirmed by experiment in this paper.

EHL, hladovění, valivá ložiska, doplňování maziva

EHL, starvation, rolling bearings, replenishment

2015

01.10.2015

Praha

1805-0476

2015/3

640–644

5