Butterfly-type throttle valve

a A butterfly valve-type throttle valve includes a valve shaft extending across an intake air passage of an internal combustion engine, and a butterfly-type valve body for adjusting a flow rate of an intake air flowing through the intake air passage by rotating in unison with the valve shaft . The valve body is constituted by two split members , and is configured such that the split members are coupled to each other by a welding , which is a coupling that uses no screw, and such that an axial hole for fitting with the valve shaft is formed through the coupling. A gap closing member is provided on a circumferential edge portion of the valve body for closing a gap between the valve body positioned at a fully closed position and a passage wall surface of the intake air passage .