Abstract: A sealing device includes an annular seal portion formed of an elastic material. On an inner peripheral surface of the seal portion, a main lip is formed so as to be in slidable contact with an outer peripheral surface of a rotary shaft, and a vacuum space side inclined surface is formed so as to gradually enlarge in diameter from the main lip toward a vacuum space side. On the vacuum space side inclined surface, a plurality of annular projections are formed along an axial direction so as to be in slidable contact with the outer peripheral surface of the rotary shaft in a state where the main lip is in slidable contact with the outer peripheral surface of the rotary shaft.

Abstract: A sealing device includes an elastic annular seal portion. On an inner peripheral surface of the seal portion, a main lip is in slidable contact with an outer peripheral surface of a rotary shaft, and a vacuum space side inclined surface gradually enlarges in diameter from the main lip toward a vacuum space side. On the vacuum space side inclined surface, a first annular projection is in slidable contact with the outer peripheral surface of the rotary shaft, and a second annular projection that projects toward a radially inward side is disposed between the main lip and the first annular projection. In an initial use state of the sealing device, the second annular projection is not in slidable contact with the rotary shaft; when the main lip wears to a degree that required sealing performance cannot be maintained, the second annular projection starts slidable contact with the rotary shaft.

Abstract: A sealing device includes an elastic annular seal portion. On an inner peripheral surface of the seal portion, a main lip is in slidable contact with an outer peripheral surface of a rotary shaft, and a vacuum space side inclined surface gradually enlarges in diameter from the main lip toward a vacuum space side. On the vacuum space side inclined surface, a first annular projection is in slidable contact with the outer peripheral surface of the rotary shaft, and a second annular projection that projects toward a radially inward side is disposed between the main lip and the first annular projection. In an initial use state of the sealing device, the second annular projection is not in slidable contact with the rotary shaft; when the main lip wears to a degree that required sealing performance cannot be maintained, the second annular projection starts slidable contact with the rotary shaft.

Abstract: A sealing device includes an annular seal portion formed of an elastic material. On an inner peripheral surface of the seal portion, a main lip is formed so as to be in slidable contact with an outer peripheral surface of a rotary shaft, and a vacuum space side inclined surface is formed so as to gradually enlarge in diameter from the main lip toward a vacuum space side. On the vacuum space side inclined surface, a plurality of annular projections are formed along an axial direction so as to be in slidable contact with the outer peripheral surface of the rotary shaft in a state where the main lip is in slidable contact with the outer peripheral surface of the rotary shaft.