| 摘要 |
A sealing device 1 includes an annular seal portion (5) formed of an elastic material. On an inner peripheral surface of the seal portion (5), a main lip (10) is formed so as to be in slidable contact with an outer peripheral surface (S1) of a rotary shaft (S), and a vacuum space side inclined surface (11) is formed so as to gradually enlarge in diameter from the main lip 10 toward a vacuum space (V) side. On the vacuum space side inclined surface (1), a first annular projection (20)is formed so as to be in slidable contact with the outer peripheral surface of the rotary shaft (S), and a second annular projection (21) is formed so as to be disposed between the main lip (10) and the first annular projection (20) and project toward a radially inward side. The second annular projection (21) is formed such that: when the sealing device (1) is in an initial use state, the second annular projection (21) is not in slidable contact with the rotary shaft (S); and when the main lip (10) wears to such a degree that required sealing performance cannot be maintained, the second annular projection (21) starts slidable contact with the rotary shaft (S). |
