| 摘要 |
When a valve body is rotated toward a full-close position in a valve-close mode, a control portion controls an electric motor so that the rotating speed of the valve body is lower than that in a valve-open mode. A rotating speed of the valve body around the shaft in the valve-close mode is lower than that in the valve-open mode. Thus, when the seal ring is brought into contact with the inner wall surface, an impact generated therebetween can be moderated. While the valve body is rotated toward the full-close position, a seal ring is gradually elastically deformed. A sliding friction between the seal ring and the inner wall surface can be reduced. |
