Muffler Having Mechanical Connection Of Tube To Partition

Abstract

A mechanical connection of a gas flow tube to a partition in lieu of spot welding is provided by means of angularly spaced projections, preferably louvers, which engage one side of a muffler partition and deformed nibs on an end of the tube engaging the end of an annular neck on the partition.

Description

BRIEF SUMMARY OF THE INVENTION

In the mass manufacture of mufflers for use on automobiles it is desirable to maintain the cost at an absolute minimum providing quality is not sacrificed, and even fractions of a cent savings per muffler are important. It is the purpose of this invention to eliminate in some instances the more costly spot welding operation normally used to connect a muffler gas flow tube to a partition and replace it by a suitable mechanical connection. In the preferred form this connection comprises angularly spaced projections on the tube which engage opposite sides of a partition and are formed at a subassembly so as to securely unit the partition and the tube.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a longitudinal cross section of a simplified form of muffler for silencing exhaust or intake gases or other flowing gases;

FIG. 2 is an enlarged view of the tube to partition connection shown in the circle 2 of FIG. 1;

FIG. 3 is a view along the line 3-3 of FIG. 2;

FIG. 4 is a section along the line 4-4 of FIG. 2; and

FIG. 5 is a somewhat schematic view showing the actual assembly of the tube and partition.

DESCRIPTION OF THE INVENTION

The simplified muffler construction 1 has a shell 3 which is closed at its inlet end by a header 5 and at its outlet end by a header 7. A single transverse partition 9 having an annular flange 11 spot welded to the shell 3 is shown as dividing the muffler into chambers 13 and 15. The partition has an annular neck 17 and seated in it is the end of a gas flow tube 19, the other end extending through and being spot welded to an annular neck 21 in the outlet header 7. The inlet header 5 has an inlet neck or bushing 23 and, in usage, gas will enter the inlet 23 to pass into the expansion and snubber chamber 13 from which it enters the tube 19 and flows along its length to leave the muffler at the rear end. Louvers 25 formed in the tube 19 acoustically connect the flowing gas to the chamber 15 which would therefore act to attenuate sound in the gas flowing through the tube 19.

In accordance with this invention, the tube 19 is mechanically connected to the partition, rather than by means of spot welds. For this purpose the wall of the tube 19 is provided with angularly spaced and radially outwardly extending dimples 27 which are preferably 3 in number. It should be noted that if the louvers 25 extend longitudinally of the tube 19 to a portion wherein they can engage the back or right side of the partition 9, they can be used instead of the dimples 27 since they are also radially extending projections, as is well known. However, the exact pattern and area covered by louvers is dictated by the acoustic requirements that must be met by the muffler and in some cases the louvers may not be properly located to serve as a means for mechanical connection.

The end of the tube 19 extends a slight distance beyond the neck 17 as most clearly seen at 29 in FIG. 2. Nonsheared nibs 31, preferably three in number, are formed in the butt end of the wall of tube 19 to press against the butt end of the neck 17 and thereby act with the dimples 27 to tightly clamp the tube to the partition 9. As seen in FIGS. 2, 3, and 4 the nibs 31 have a center web 33 and opposite side walls 35 all integrally united to form a ramplike continuous structure.

In FIG. 5, is schematically illustrated a subassembly method for forming the nibs 31 and clamping the tube 19 to the partition 9. As is illustrated, there is a backup plate 37 for the partition 9 to hold it in fixed position. Located in alignment with the neck receiving hole 39 of the backup plate 37 is a fixed die 41 that has triangular or wedge shaped projections 43 which engage portions of the end of the tube 19 to deform them outwardly into the nibs 31 when force is applied to the tube as by a ram structure 45.

It is apparent that the assembly operation of FIG. 5 can be performed rapidly in accordance with mass production requirements and that the result is a strong permanent interconnection of the tube and the partition. The neck sizing operation and other expense of spot welding has been eliminated without sacrifice in strength or durability.

Modifications may be made in the structure illustrated without departing from the spirit and scope of the invention.

Claims

I claim:

1. A muffler for silencing sound in flowing gases comprising a housing, a partition secured in the housing having an annular neck extending at substantially right angles to the plane of the partition and defining an opening, a gas flow tube in the housing extending through said neck opening and supported in said neck, means for mechanically clamping the end of said tube to said partition in said neck comprising a first set of radially outwardly extending ramplike projection members formed in the tube and including at their points of maximum radius the butt end of the tube, and a second set of radially outwardly extending projection members formed in the tube and spaced from the first set by substantially the length of said neck, one set of said projection members engaging the butt end of the neck and the other engaging the partition on the side thereof opposite the butt end of the neck, said ramplike projection members compressing said neck and partition against said second set projection members to tightly clamp said tube in position in said neck.

2. A muffler as set forth in claim 1 wherein said ramplike projection members engage the butt end of said partition neck.

3. A muffler as set forth in claim 2 wherein said second set of projection members are louvers in the tube.

4. A muffler as set forth in claim 1 wherein said second set of projection members are louvers in the tube.

5. The method of making a muffler which comprises forming a partition with an annular neck and a gas flow tube with radial outwardly extending projections spaced from one end thereof, inserting the tube through the neck so that the projections engage the partition on the side opposite the neck, inserting a tool in the end of the tube and deforming the end of the tube radially outwardly without shearing it so that at least a portion of the tube engages the butt end of the neck, applying axial force to said deformed portion to tightly clamp the partition against the projections, inserting the partition and attached flow tube inside of a muffler shell and spot welding the partition to the shell, and closing the ends of the shell.