| 摘要 |
PROBLEM TO BE SOLVED: To surely seal the periphery of a through hole by a pair of inner/outer annular seal lips protrusively provided in the periphery of the through hole in a boots side wall. SOLUTION: A pair of inner/outer annular seal lips 17, 18 coaxial to each other are protrusively provided in the periphery of a through hole 16 provided in a side wall of boots 10, also a protrusive height of one seal lip 17 of these annular seal lips is made higher than a protrusive height of the other seal lip 18. In this way, when an air-tight seal is formed by compressing a pair of the inner/outer annular seal lips 17, 18 in an axial line direction of the through hole 16, timing of a pair of the inner/outer annular seal lips 17, 18 respectively compressed to start deformation can be deviated, consequently a pair of the inner/outer annular seal lips 17, 18 are prevented from repulsing each other in a radial direction, so that high seal performance can be ensured by most suitably controlling this deformation.
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