| 摘要 |
PROBLEM TO BE SOLVED: To provide a shaft sealing structure of a butterfly valve dispensing with a bearing, and pressing a seal ring to a waterproof face of a valve element. SOLUTION: In this butterfly valve, a valve element 3 rotating around a shaft center of a valve rod 2 is mounted inside of a valve casing 1, and the valve rod is inserted into a boss part 7 of the valve casing 1. An engagement part 23 having a diameter larger than the other part, is formed on a specific part of the valve rod 2 corresponding to the boss part 7, the seal ring 10 engaged with a step part 24 at one end side of the engagement part 23 in the shaft center direction of the valve rod 2 is mounted in a state of being slid and kept into contact with the waterproof face 9a around the valve rod, of the valve element 3, and a pressing plate 28 engaged with a step part 25 at the other end side of the engagement part 23 in the shaft center direction of the valve rod 2 is mounted on the boss part 7 by means of a fastening bolt 13. COPYRIGHT: (C)2004,JPO&NCIPI
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