| 摘要 |
PROBLEM TO BE SOLVED: To improve the screw pumping effect by providing a first multiple thread screw provided on a sealing fluid side of a slidably contact surface of a seal lip, and a second multiple thread screw which is provided on the side opposite to the sealing fluid side of the slidable contact surface of the seal lip, and set to the angle different from the angle to the rotational direction of the first multiple thread screw. SOLUTION: A first multiple thread screw 32a and a second multiple thread screw 32b are formed on a slidable contact surface of a seal lip 32, and the first multiple thread screw 32a is provided on a sealing fluid side O, and the second multiple thread screw 32b is provided on the side opposite thereto (atmospheric side A). The angle of the first multiple thread screw 32a relative to the rotational direction is set to be different from the angle of the second multiple thread screw 32b relative to the rotational direction. The contraction is generated in the flow of the fluid by the flow generated by the first multiple thread screw 32a and the flow generated by the second multiple thread screw 32b to gradually increase the flow speed, and the pumping function to return the fluid leaked to the atmospheric side to the sealing fluid side is improved. The screw pumping effect can be improved. |
