| 摘要 |
PROBLEM TO BE SOLVED: To maintain expected sealability over a long period, while restraining an increase in sliding resistance of a shaft body and a cylindrical body, in a seal structure for sealing a mutual fitting surface of the shaft body (for example, a push rod 12) arranged in a liquid flow passage 2 and the cylindrical body (for example, a guide member 11). SOLUTION: A part between the push rod 12 and the guide member 11 is sealed by a main seal ring 20 in the initial use stage, and when sealability of a shoe seal ring 20 reduces in response of progress of use, the sealing function by an auxiliary seal ring 21 is validated. Thus, while restraining or preventing an increase in the total sliding resistance in sliding operation, the expected sealability can be maintained over a long period. COPYRIGHT: (C)2006,JPO&NCIPI
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