Lubricant Rupture Ratio at Elastohydrodynamically Lubricated Contact Outlet

Elastohydrodynamically lubricated (EHL) contacts rarely exist as single contacts. Multiple contacts or single contacts subjected to the repeated over-rolling represent more often the case in practical applications. A typical example is the rolling element bearing. A lubricant rupture mechanism at each contact outlet determines the lubricant availability to the succeeding contact. This work presents a quantitative description of the lubricant film thickness rupture in EHL contact outlet with the use of the fluorescent microscopy. A rupture ratio of the film thickness between two diverging surfaces exiting the contact was measured for both pure rolling and rolling-sliding conditions. The influence of variation of several parameters such as lubricant properties, rolling speed or rolling element ellipticity to the lubricant rupture ratio was investigated. Understanding of the physical phenomena of the lubricant rupture extends further possibilities in both experimental and theoretical researches of the starved EHL.