EXHAUST PASSAGE CONTROL VALVE

摘要

PROBLEM TO BE SOLVED: To miniaturize an exhaust passage control valve so constructed that a spiral valve element 21 is mounted on a valve seat portion 20a of a housing 20 where engine exhaust gas flows, and that a torsion coil spring with a coiled barrel portion 22a and arm portions 22b at both ends thereof is used as a valve spring 22 for urging the valve element to the closing side, with the arm portions fitted in a pair of spring bearings 23 on both sides of the housing 20 so as to urge the valve element to the closing side via the barrel portion, by reducing the degree of radially outward projection of the spring bearings relative to the valve seat portion. SOLUTION: The pair of spring bearings 23 are arranged in line symmetry with respect to a first diametral line (a) of the valve element 21. The barrel portion 22a of the valve spring 22 is supported on the valve element 21 with its own centerline c obliquely intersecting the first diametral line (a) so that arm portions 22b of the valve spring 22 obliquely intersect a second diamertral line b perpendicular to the first diametral line (a) in the region of the spring bearings 23.