| 摘要 |
A bearing seal includes a bearing housing which houses a rotatable shaft, with a flange of the shaft located outside the housing and an internal annular volume residing between the bearing housing and the shaft, the annular volume bounded at one axial end by the flange. A seal resides in a recess in an outer surface of the housing, the seal including an outwardly extending resilient lip which engages the flange to close off the annular volume at the first axial end, adjacent the flange. The bearing housing includes a fluid passage which extends from an outer surface thereof to the annular volume, the passage including an innermost section oriented tangential to the annular volume. Purge fluid supplied to the annular volume via the external passage causes circumferential flow and substantially radially uniform purge fluid pressure within the annular volume. Build up of the purge fluid pressure in the annular volume eventually causes the lip to flex away from the flange to cause substantially uniform outward flow of purge fluid around the periphery of the seal, thereby to prevent ingress of contaminants.
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