| 摘要 |
PROBLEM TO BE SOLVED: To provide a sealing device simple in constitution and improved in a pumping function. SOLUTION: A screw 21 has outer wall surfaces 21a, 21b extending approximately vertically to a surface of a seal lip as both outer walls and has a pentagonal shape of a cross section, and a height B of the whole screw 21 can be made larger by making ΔB large with a vertex angle α, base angles β, γ, and a height B0 of a triangular cross sectional part of a tip of the screw 21 being constant. Even in this case, the height B of the screw 21 is freely set without reducing the number of the screws since a length A of a base of the screw 21 can be maintained to be constant and an interval C between adjacent screws is not changed. |
