BUTTERFLY VALVE

To provide a butterfly valve which can control pressure from the atmospheric pressure to a high vacuum region while exerting high sealability when the valve is closed, which reduces an end-to-end distance by a simple structure to reduce the size even when being provided in a large diameter, and which improves the efficiency of operation from valve closing to valve opening to be capable of smooth and quick opening/closing control, while maintaining the sealability and highly-accurate flow control.SOLUTION: A stem 3 is tiltably and rotatably mounted to a body 2 via a support portion 12, and a valve element 4 opens and closes a valve seat seal surface 11 in the body 2. A drive body 5 is provided on the side opposite to the valve element 4 across the support portion 12 for the stem 3. The drive body 5 includes tilting cam grooves 31 and a rotating cam groove 32, tilting cam rollers 23 are engaged with the tilting cam grooves 31, and a rotation guide roller 20 is engaged with the rotating cam groove 32, so that the stem 3 is mounted to be tiltable and rotatable and to be movable up and down in the stem shaft mounting direction. The support portion 12 is provided at a position eccentric in the direction opposite to the valve seat seal surface 11 with respect to a central axis P2.SELECTED DRAWING: Figure 2 【課題】弁閉時に高シール性を発揮しつつ大気圧から高真空領域まで圧力制御可能であり、大口径に設ける場合にも簡単な構造により面間距離を抑えて小型化し、シール性と高精度の流量制御を維持しつつ、弁閉から弁開までの動作の効率を向上してスムーズかつ迅速に開閉制御可能なバタフライバルブを提供する。【解決手段】ボデー２に支承部１２を介してステム３が傾動及び回転自在に取付けられ、弁体４でボデー２内の弁座シール面１１を開閉する。ステム３の支承部１２を挟んで弁体４との反対側に駆動体５が設けられる。駆動体５は、傾動用カム溝３１と回転用カム溝３２とを備え、傾動用カム溝３１に傾動用カムローラ２３、回転用カム溝３２に回転ガイドローラ２０が係合されてステム３が傾動及び回転可能にステム軸装方向に昇降動自在に取付けられ、支承部１２は中心軸Ｐ２に対して弁座シール面１１との反対方向に偏芯した位置に設けられる。【選択図】図２