| 摘要 |
PROBLEM TO BE SOLVED: To minimize the leakage of a lubricant and to effectively reject contaminants under severe operation conditions by providing sealing lips protruding in the axial direction from the first annular face of an annular sealing member and cooperating with the sealing face of a second machine member facing the first annular face by sliding. SOLUTION: An annular sealing member 7 is elastically deformed and is selectively located at operation positions 7a or 7b depending on the pressure difference between annular faces 36, 37. When both annular faces 36, 37 practically receive the same pressure and the pressure difference exceeding the prescribed value is generated at one operation position 7a where only a lip section 13 cooperates with a sealing face 8 by sliding, the annular sealing member 7 is elastically deformed, and a lip section 23 likewise cooperates with the sealing face 8 by sliding. The annular sealing member 7 prevents the infiltration of contaminants between itself and the sealing face 8 more satisfactorily with both lip sections 13, 23 cooperating with the sealing face 8 by interference.
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