SHAFT SEAL HAVING TRANSITIONAL CONTACT

摘要

A bearing assembly including a housing, a bearing, and a shaft in the bearing. The assembly includes a seal mounted in the housing and around the shaft. The seal has an inner surface having a tapered portion spaced from the shaft by a clearance gap having a predetermined axially varying width. The width of the gap decreases from a bearing side toward an opening side. The inner surface includes an axially extending sealing portion having an inner diameter corresponding to the shaft and forming a sealing interface. The interface supports tribological film lubrication when the shaft rotates relative to the housing to reduce shaft wear and contacts the shaft when the shaft is stationary relative to the housing to prevent contaminants from entering the interior cavity of the housing through the interface.

主权项

1. A bearing assembly, comprising:
a housing having an interior cavity adapted to hold a lubricant, an opening extending from the interior cavity to an exterior of the housing, an inward facing seal mounting surface, and an inward facing bearing seat; a bearing positioned in the interior cavity of the housing having a central axis, said bearing including an outer race mounted in the inward facing bearing seat of the housing and an inner race centered on the central axis and freely rotatable in the outer race; a shaft mounted in the inner race of the bearing for rotation with the inner race about the central axis of the bearing, said shaft having an outer surface extending along the shaft from the interior cavity through the opening to the exterior of the housing, at least part of the outer shaft aligned with the opening having a sealing diameter; and a seal mounted in the seal mounting surface of the housing and around the outer surface of the shaft, the seal being positioned axially along the shaft between the interior cavity of the housing and the exterior of the housing to inhibit contaminants from entering the interior cavity of the housing through the opening and damaging the bearing, the seal including an annular body having a bearing side facing the bearing, an opening side opposite said bearing side, and an inner surface facing the outer surface of the shaft, said inner surface having a tapered portion spaced from the outer surface of the shaft by a clearance gap having a predetermined axially varying width, said width of the clearance gap decreasing from the bearing side toward the opening side, and said inner surface including an axially extending sealing portion having an inner diameter corresponding to the sealing diameter of the outer surface of the shaft and forming a sealing interface with the outer surface of the shaft, said interface supporting tribological film lubrication when the shaft rotates relative to the housing to reduce shaft wear and contacting the shaft when the shaft is stationary relative to the housing to prevent contaminants from entering the interior cavity of the housing through the interface.