Structuring air duct

Air duct of a motor vehicle, extending in a direction of elongation and comprising two half-shells arranged opposite one another, such that:

• each half-shell has:
• a tubular portion extending in the direction of elongation of the duct, the tubular portions defining between them an air cavity extending in said direction of elongation;
• two lateral flanks extending one on each side of the tubular portion and each having a contact surface in contact with one of the contact surfaces of the other half-shell, and
• a continuous weld seam extends substantially in the direction of elongation of the duct between the contact surfaces of the half-shells which are in contact with one another, wherein said half-shells also have two stop elements having the following features:
• each stop element defines a rib extending in the direction of elongation of the duct and projecting relative to one of the contact surfaces,
• each stop element has, in a direction perpendicular to the contact surface relative to which it projects, and end region,
• each stop element has a stop surface extending between the end region and one of the contact surfaces, said stop surface belonging to one of the half-shells and being in the immediate vicinity of an abutment surface provided on the other half-shell.