Patent ID: 7806412

Claim:
A sealing device comprising: a seal lip being integrally provided at an annular case arranged to be fixed on an inner peripheral face of a housing, the seal lip being opened in a tapered shape to the sealed liquid side; a slinger arranged to be tight fitted to an outer periphery of a rotary shaft inserted in the inner periphery of the housing and being slidably contacted with the seal lip at a flange part; and a dust cover arranged to be tight fitted on the outer periphery of the rotary shaft so as to be positioned at an atmosphere side of the slinger, and having a dust lip slidably contacted with the case at an outer periphery side of the dust cover, wherein the dust cover comprises a vent passage for releasing pressure in a seal internal space between sliding parts of the seal lip and the dust lip to the atmosphere side, and a dust filter provided in the vent passage; and the vent passage spirally extends along a fitting part to the rotary shaft in an inner peripheral part of the dust cover.