Patent ID: 8608177

Claim:
A sealing system which serves to seal an annular gap between an inner peripheral surface of a shaft hole formed in a housing and an outer peripheral surface of a shaft which is inserted through said shaft hole and carries out a reciprocating movement relative to said housing, said system comprising: a main seal that prevents fluid to be sealed from leaking to an atmospheric air side; and a dust seal that is arranged at a location nearer to the atmospheric air side than said main seal, for preventing dust from invading to a side of the fluid to be sealed; wherein said dust seal is composed of a first dust seal and a second dust seal which is arranged at a location nearer to the atmospheric air side than said first dust seal, and each of said first dust seal and said second dust seal has an axially extending seal lip extending toward said atmospheric air side and formed so as to be slidable with respect to the outer peripheral surface of said shaft; the seal lip of said first dust seal is made of urethane rubber; and the seal lip of said second dust seal is made of a rubber which is higher in flexibility than said urethane rubber, and is composed of only a seal lip that extents toward the atmospheric air side.