Patent attributes
A synthetic resin intake manifold body and a synthetic resin passage structural member are respectively provided with a body side joining flange and a structural member side joining flange that are continuously formed along a joining line. A protrusion is provided on the body side joining flange and a welding protrusion and an inside and an outside control wall are provided on the structural member side joining flange. When the synthetic resin passage structural member is positioned and aligned with respect to the synthetic resin intake manifold body along the joining line prior to welding, a volume of an inside burr retaining groove is set to be larger than a volume of an outside burr retaining groove.