Patent ID: 7310942

Claim:
An exhaust passage control valve comprising: a housing having an exhaust passage through which exhaust gas from an internal combustion engine flows; a valve member for opening and closing the exhaust passage of the housing when pressure of the exhaust gas flowing through the exhaust passage is equal to or above a predetermined value, the valve member moving with respect to the housing between a closed position and an open position, wherein the valve member closes the exhaust passage when the valve member is in the closed position, and wherein the valve member opens the exhaust passage when the valve member is in the open position; a helical torsion spring disposed at the opposite side of the valve member from the housing side thereof, the helical torsion spring comprising a coil part wherein spring wires have been wound in a coil shape, and arms formed at both ends of the coil part, the coil part being disposed at approximately the center of the valve member and, when the arms bends with respect to the coil part, the counter-force of this bending energizing the valve member towards a closing side; and a spring mounting member mounted on the housing, the spring mounting member having a guiding part for guiding the valve member, the spring mounting member supporting the arms of the helical torsion spring in a manner allowing the arms to slide in a longitudinal direction of the arms, and the spring mounting member being arranged and constructed to adjust a mounting position in which the spring mounting member is mounted on the housing, wherein a rotation angle of the arms when the valve member is in the closed position is changed by changing the mounting position, and wherein the valve member moves between the closed position and the open position while being guided by the guiding part.