摘要 |
A lip seal includes: a lip part (1) forming a ring shape alone or with plural members and provided in sliding contact with the entire periphery of a surface of a shaft (0); an elastic arm part (2) and a flexible wall (3) supporting the lip part (1) at a sliding contact position; key parts (4) connecting the elastic arm part (2) and the flexible wall (3) to a housing (10), respectively, and a pressure regulation chamber (A) forming a ring shape alone or with plural members and using the elastic arm part (2) and the flexible wall (3) as partition walls. The flexible wall (3) is deformed by the increase and decrease in pressure in the pressure regulation chamber (A) to change the lip part (1) at least radially. |