Experimental study of porous foil bearings for web-handling

In this paper, new type of hybrid porous foil bearings for web-handling is presented, in which the traveling web is supported by the externally pressurized porous foil bearings with the hybrid effects of hydrodynamic pressure, due to web movements, and hydrostatic pressure, due to pressurized, added flow through the hollow porous shaft. The relations between web spacing height (air film thickness) and web traveling velocity are measured under various supply pressures. Moreover, the relations between web spacing height and web tension are examined. From these measured relations, the hybrid effects of porous foil bearing on the web spacing height characteristics are clarified experimentally, and it is concluded that the hybrid porous foil bearings presented here have an advantage of controlling the web spacing height to keep suitable web-handling conditions.