Patent ID: 7406823

Claim:
An exhaust gas throttle valve disposed in an exhaust system of an engine, comprising: a valve casing having an exhaust gas passage of a circular shape in cross section through which exhaust gases flow, insertion holes of a circular shape in cross section formed in a wall portion of said exhaust gas passage, a rotary valve shaft fitted into said insertion holes and penetrating through said exhaust gas passage, the center axis of rotation of said valve shaft being set at a position deviated from the center axis of said exhaust gas passage, and, a plate-like valve body attached to said valve shaft having two recessed portions symmetrically formed in said valve body by cutting a surface of said valve body by its partial thickness at positions facing edge portions where said insertion holes are opened in said exhaust gas passage, said two recessed portions being formed in the circumferential portion of said valve body on a side of said center axis of said exhaust gas passage beyond said center axis of rotation.