The Influence of Vacuum Cavity Position on Vacuum Preloaded Porous Aerostatic Bearing
With the characteristics of balance between negative pressure and positive pressure,the vacuum preloaded porous aerostatic bearing can improve the bearing rigidity.This bearing can not only ensure the precision of the guideway,but also reduce the number of support points and simplify the structure.Aiming at the influence of the position change of vacuum cavity on the static characteristics of bearing,the fluid models of outer-edge,embedded-edge and inner-edge vacuum preloaded porous aerostatic bearings were es-tablished,and fluid simulation was carried out by FLUENT.And the variation laws of flow field pressure,bearing capacity,static stiffness and gas consumption under the same bearing area were revealed.The com-parative analysis show that different positions of vacuum cavity had different preload effects,which lead to different static characteristics.The change of vacuum cavity position lead to different bearing stiffness under different film thickness.It is important to arrange the position of the vacuum cavity according to the load and the thickness of film for achieving high stiffness bearings.
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