Conventionally, as a sealing device, there is one described in JP-UM-A-4-93571 Publication (Patent Literature 1).
This sealing device is disposed between an inner race and an outer race of a rolling bearing for a wheel. This sealing device comprises a core metal member, an elastic member fixed to the core metal member, a cross-sectionally L-shaped slinger, and a garter spring. The slinger includes an axially-extending portion, and a radially-extending portion, and the elastic member includes a radial lip always sliding on the axially-extending portion, a first axial lip sliding on the radially-extending portion, and a second axial lip disposed radially inwardly of the first axial lip and sliding on the radially-extending portion. The second axial lip has an annular groove formed in a radially-outward surface thereof.
The garter spring is fitted in the annular groove of the second axial lip. The garter spring presses the second axial lip radially inwardly.
This sealing device is formed such that in a condition in which the second axial lip is not worn, the second axial lip is not in contact with the axially-extending portion, while when the second axial lip is worn, so that a press-contacting force of the second axial lip for the radially-extending portion becomes less than a predetermined force, part of that portion of the second axial lip opposed to the axially-extending portion is brought into contact with the axially-extending portion, so that part of the above opposed portion forms a radial seal.
The second axial lip, when not in a worn condition, functions as an axial seal, while in a worn condition of the second axial lip, part of the above opposed portion of the second axial lip functions as the radial seal, so that this sealing device can continuously maintain a stable sealing function.
Patent Literature 1: JP-UM-A-4-93571 Publication (FIG. 1).