MANUFACTURE OF SUCTION MANIFOLD

PURPOSE:To decrease the air resistance and to make the suction manifold light in weight by dividing vertically a plenum chamber, setting a flare of a branch pipe to the inside and allowing it to pass through a hole, joining the branch pipe and a constituting member and manufacturing a suction manifold. CONSTITUTION:A tubular body 3 is formed by joining two constituting members 5, 6 made of an aluminum expanded material divided into two by a horizontal plane containing an axis. On the constituting member 5 of the upper side, a hole 15 is provided, a branch pipe 2 is fitted into this hole, and a flare 16 of an end part of the branch pipe 2 adheres closely to the inside surface of the constituting member 5. A connecting part of the branch pipe 2 and the flare 16 is made round 17. As for this radius of curvature, >= about 10mm is desirable. In such a way, the radius of curvature of roundness of the inside peripheral surface of a main pipe and the branch pipe connecting part can be set freely, the air resistance is decreased and the performance of the suction manifold can be improved, and also, it can be made light in weight.