Valve device for exhaust flow passage

A valve device for an exhaust flow passage comprising:

• a valve body to open and close an exhaust flow passage;
• a support body that supports the valve body in a rotationally movable manner;
• a link comprising a first link-forming member and a second link-forming member, which are coupled to each other so as to be rotationally movable with respect to each other, the link coupling the support body and the valve body in a first arrangement in which the first link-forming member is supported by the support body in a rotationally movable manner and in which the second link-forming member is supported by the valve body in a rotationally movable manner;
• and
• a biasing member to bias the valve body in a closing direction,
• wherein the link comprises:
• a link length that is a length of the first link-forming member, as measured between a rotation axis with respect to the support body and a rotation axis with respect to the second link-forming member;
• and a link length that is a length of the second link-forming member, as measured between a rotation axis with respect to the valve body and a rotation axis with respect to the first link-forming member, the link lengths being different from each other, and
• wherein the link is also configured to enable coupling between the support body and the valve body in a second arrangement in which the first link-forming member is supported by the valve body in a rotationally movable manner and in which the second link-forming member is supported by the support body in a rotationally movable manner.