| 摘要 |
A valve device includes a butterfly valve and a first link member each supported by a stay so as to be rotationally movable about a first rotation axis and a second rotation axis, respectively, a second link member supported by the butterfly valve so as to be rotationally movable about a third rotation axis, and a spring to bias the butterfly valve in a valve closed direction. The first link member and the second link member are connected to each other so as to be mutually rotationally movable about a fourth rotation axis. An angle formed by a first link line connecting the second rotation axis and the fourth rotation axis to each other and a second link line connecting the third rotation axis and the fourth rotation axis to each other is formed to be the largest when the butterfly valve is in a valve closed state. |
