Valve device

A valve device configured to increase or decrease a flow rate of EGR gas, the valve device comprising:

• a housing that includes a first upstream passage into which the EGR gas cooled by an EGR cooler flows, a second upstream passage into which the EGR gas that bypasses the EGR cooler flows, and a downstream passage connected downstream with respect to the first upstream passage and the second upstream passage;
• a bypass valve body that opens and closes the second upstream passage;
• an EGR valve body that is provided in the downstream passage and rotates around an EGR valve axis to open and close the downstream passage;
• and
• an interlocking portion that interlocks the bypass valve body with a rotational operation of the EGR valve body, wherein
• a first case is defined as the EGR valve body rotating around the EGR valve axis from a reference rotational position, which is predetermined, to one side,
• a second case is defined as the EGR valve body rotating around the EGR valve axis from the reference rotational position to an other side,
• the EGR valve body is configured such that a relationship between a rotation amount from a reference rotational position, which is predetermined, and an opening degree of the downstream passage is same in a first case where the EGR valve body rotates around the EGR valve axis from the reference rotational position to one side and a second case where the EGR valve body rotates around the EGR valve axis from the reference rotational position to an other side, and
• the interlocking portion has a structure configured to interlock an opening degree of the second upstream passage with the opening degree of the downstream passage in a non-linear relationship when the second upstream passage and the downstream passage are open.