Patent attributes
On a seal lip, first screw projections are arranged from an atmosphere side slope surface to the middle of a sliding surface, and second screw projections are arranged on the sliding surface. The end section on the sliding surface side of a first screw projection has a shape (cutout section as if the section is cut out along the sliding surface, and a portion on the atmosphere side slope surface side of the first screw projection has an equi-width section with a shape where the height of the section increases toward the atmosphere side with the width kept substantially the same. Therefore, a sealing device is easily processed, and, at an early stage and for permanence, the sealing device provides a screw pump effect that exhibits excellent sealing ability for a long period.
