MUFFLER AND METHOD FOR FABRICATING THE SAME

摘要

A vehicular exhaust system muffler including a reversing unit sub-assembly having spaced apart internal panels; and flow tubes that extend between the internal panels and that have their ends mechanically locked within flanged apertures in the internal panels. A sheet metal wrapper is formed around the peripheries of the panels so that the wrapper is in contact with but is metallurgically unbonded to the panels and so that ends of the flow tubes are adjacent to the side edges of the wrapper. End cap sub-assemblies are assembled onto each end of the reversing unit sub-assembly and wrapper. Each end cap sub-assembly includes an end panel having an aperture surrounded by a flange that projects from one side surface of the end panel, and an end tube that extends through the end panel flanged aperture. One end of each end tube has an outer diameter selected such that the one end may be loosely, telescopically and overlappingly fitted within the adjacent end of the adjacent flow tube. The overlapped ends of the end tubes and the flow tubes are mechanically locked together by a circumferential skewed bead formed in the overlapped ends, where the plane of the skewed bead is at an angle less than ninety degrees with respect to the central longitudinal axis of the overlapped ends. This mechanical locking maintains the relative axial positions of the overlapped ends and resists relative movement between the overlapped ends and between the internal panels and the wrapper due to the application of torsional and axial forces that the tubes experience during the assembly of the muffler. The end tubes are also mechanically locked within the end panel apertures. This mechanical locking includes a continuous, circumferential bead that is formed in the part of the end tube adjacent to side surface of the end panel opposite its