A sub-muffler having a polygonal shape in cross section, the sub-muffler being connected to an inflow pipe and a discharging pipe and being housed in a floor tunnel extending in a longitudinal direction of a vehicle and providing a space formed between a w...

The invention relates to a method for producing a torsion profile from a tubular hollow profile (1), wherein the torsion profile is provided with spaced walls over its entire length, comprising the following method steps: a) inserting the tubular hollow pr...

A manufacturing method of a sub-muffler includes a rectangular tubular body shaping step (S3), a preliminary shaping step (S5), and a diameter reduction shaping step (S7). In the rectangular tubular body shaping step (S3), a plate material is bent and a re...

A method of press-forming a tubular part having a cross section of an irregular shape crushes a steel tube between an upper die and a lower die in order to form a V-shaped cross section. When the curvature radius of a tip of the upper die is defined as R 1...