| 摘要 |
PROBLEM TO BE SOLVED: To maintain a good sealing force even if seal rings wear and to adjust the sealing force without replacing the seal rings in use. SOLUTION: This linearly moving drive mechanism comprises a seal holder 16 attached to a nut 13, two seal rings 17 held within the seal holder 16, and a tensile coil spring 18 extended between the seal rings 17. An arcuate cutout 34 is provided in a portion of the outer peripheral surface of each seal ring 17, and three post holes are arranged in circumferentially parallel relationship at the corners of each cutout 34. The seal rings 17 are mated together so that the post holes in one of the seal rings are spaced apart from the post holes in the other of the seal rings, and so that the cutouts 34 in both seal rings coincide with ceach other. A post 36 is driven into one of the post holes in each seal ring, and the hooks 18a of the tensile coil spring 18 are hooked to the posts 36 of both seal rings. The tensile coil spring 18 applies tensile forces in the rotating direction of a threaded shaft 12 to the seal rings 17, so that the seal rings 17 tighten the threaded shaft.
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