|Title of Invention||
A VEHICLE MUFFLER
|Abstract||A vehicle muffler, which is structured in a coiled fashion, has a tube (31) extending through the circumferential wall (7), this tube on the one hand being welded to the circumferential wall (7) and on the other hand being fastened by mechanical deformation to a support wall (23) of an inner insert piece.|
EMCON Technologies Germany (Augsburg) GmbH
A 3051 WO
The invention relates to a vehicle muffler comprising opposite outer end walls,
a closed outer circumferential wall formed by coiling a sheet metal part, at least
one muffler insert, at least one inlet tube and at least one outlet tube.
The invention relates in particular to a transverse downstream muffler.
Concerning the manufacturing of the circumferential wall, mufflers are divided in
two modes of manufacturing, namely mufflers made up of a shell construction
and such made up of a coiled construction. In the case of a shell construction two
deep-drawn sheet metal parts are connected with each other at their edge, while
with the coiled construction a sheet metal part is coiled around a core and is
closed, subsequently the insert piece and the outer plates are inserted from the
side and then closed axially by crimping.
The invention relates to a vehicle muffler in coiled construction. Usually, the
gas inlet and gas outlet are provided on the end walls, namely optionally at
opposite sides or on the same side. It is also common to lay the gas inlet through
a circumferential wall into the muffler, with the inlet tubes being welded with their
ends to the circumferential wall.
The invention relates to an exhaust gas muffler in which the connection
between the tube associated with the circumferential wall and the circumferential
wall itself is more stable and stands under less strain.
This is achieved in an exhaust gas muffler of the type initially mentioned in
that one of the tubes extends through the circumferential wall into the muffler
interior and is fastened to this circumferential wall and the insert piece. Thus, the
tube is not only connected with the exhaust gas muffler through the
circumferential wall, but is consequently supported at two spaced points on and
in the exhaust gas muffler. This also has the advantage that a second vehicle-
side supporting outside the exhaust gas muffler, which has been provided up to
now, may be dispensed with. The fastening of the tube to the insert piece is not
- 2 -
restricted to an axial slide bearing, which would only act radially relative to the
longitudinal extension of the tube. Rather, the tube is firmly connected with the
insert piece both in its axial and radial direction.
The fastening of the tube to the insert piece is preferably done by mechanical
deformation. This mode of fastening is less susceptible to corrosion than welding.
Further advantages over welding are the smaller distortion of the components
and the higher strength.
A mechanical deformation can also be performed starting in the tube interior,
which is of advantage to the effect that the tube end with a previously closed
circumferential wall is not accessible from outside any more.
The tube and the insert piece are usually pressed onto each other.
It lends itself to connect the entire tube along its circumference with the insert
piece in the region of the contact area. As an alternative, a segment-wise
connection of the circumference is also possible.
According to the preferred embodiment the insert piece has at least one inner
end wall for the formation of a chamber, a support wall being fastened to this
inner end wall to which, in turn, the tube is fastened. The support wall, however,
usually lies fastened between two opposite end walls.
A preferred embodiment makes provision that the insert piece, to which the
circumferential wall is fastened which extends through the tube, is clamped in
longitudinal direction of the muffler merely by the tube. This preferred
embodiment allows an unhindered thermal expansion of the insert piece in axial
direction (axial related to the muffler axis).
It would also be possible, however, to provide more than one tube which is
coupled with the muffler interior via the circumferential wall, so-called multi-pass
systems (in particular two-pass and four-pass systems). Here, the invention
provides for two tubes, for instance, which protrude through the circumferential
wall into the muffler interior, which are fastened at their free end pieces to two
neighboring insert pieces.
Further features and advantages of the invention will be apparent from the
following description and the following drawings to which reference is made and
- Figure 1 is an exploded view of a two-pass embodiment of the vehicle
muffler according to the invention,
- Figure 1a is a sketch of the circumferential wall of the muffler according to
- Figure 2 shows an enlarged view of the middle region of the muffler
according to Figure 1,
- Figure 3 is a view, partly in cross-section, of a one-pass muffler according to
- Figures 4 and 5 are sectional views through the region of the coupling of the
inlet tube to the insert piece according to two different embodiments; and
- Figure 6 schematically shows a cross-section through the region of the
coupling of the inlet tube to the insert piece according to an alternative
Figure 1 illustrates a transverse two-pass vehicular exhaust gas muffler, in the
following briefly referred to as vehicle muffler or muffler only. The muffler has an
outer housing made up of opposite outer end walls 3, 5 and a circumferential wall
7 which is illustrated in Figure 1a in a somewhat simplified manner. The
circumferential wall 7 is coiled from a sheet metal part, with the outer longitudinal
edge 9 being welded to the inner edge portion after coiling. As an alternative, the
two longitudinal edges may also be connected with each other by crimping.
In Figure 1 the circumferential wall is omitted so that the muffler interior can
be better viewed. The muffler interior can be divided in two halves, namely a left
and a right half. These halves are separated by end walls 11,13 which are axially
spaced from each other. The left half has further end walls 17, 19, which are
provided with through-flow openings 15 and subdivide the left half in three
chambers 34, 36, 37 in total. An outlet tube 21, 39 in each of the halves is
provided with (not illustrated) openings at thet outer periphery and extends
through the end walls 3, 5, 17 and 19, it being welded at least to the end wall 3
and 5, respectively. Arranged between the end walls 11, 19 is a support wall 23
made of sheet metal and welded to the end walls ,11, 19.
As can be seen in Figure 2, the end wall 19 is connected with the end walls 3
and 17 through further connection tubes 25, 27 of differing cross-section. The
end walls 17, 19, 11 together with the tubes 25, 27 and the support wall 23 form a
muffler insert which is surrounded by the sheet metal part.
The support wall 2.3 has, as can be clearly seen in Figure 2, cross-shaped
embossments 29 which enhance its stability. An inlet tube 31 extends through an
opening in the circumferential wall 7 (see Figure 2) and is welded to it along the
entire tube circumference. The inlet tube 31 extends further into the muffler
interior and also through a relative tight opening in the support wall 23 (see also
Figures 4 and 5). The support wall has, in the region of the passage opening for
the inlet tube 31, a sleeve-shaped edge 33 which is produced by plastic
In Figures 1 and 2 it can be seen that the left half the inlet tube 31 ends
shortly after having passed through the support wall 23. At a certain distance
from this point, a connection tube 27 begins which has a 90° bend. The tube 27
extends through aligned through-flow openings 15 of the end walls 17, 19.
As can be seen from a comparison of the left and right halves, the inlet tube
31 of the right branch opens into a thicker connection tube 35 which leads into a
middle chamber 37. The outlet tube 39 of the right branch opens likewise into this
middle chamber 37. Moreover, further tubes 25 between the end walls 5, 13, 17,
19 are also provided in the right branch, with corresponding end walls having
reference symbols which have already been introduced for the left half. Some of
the tubes 25 may be stabilizing bars which are provided between the end walls
and have no gas flowing through them.
The outlet tube 39 also extends through the outer end wall 5 and is welded to
it. In the widened ends of the outlet tubes 21, 39 so-called end tubes 41 are
inserted from the outside. The same applies for the inlet tubes 31. These also
have an outwardly, widened end, into which so-called intermediate tubes 43 are
In the following the manufacturing of the exhaust gas muffler according to the
invention will be explained. First, the insert pieces consisting of the inner end
walls and the connection tubes as well as the support wall 23 are produced and
connected with the outer end walls 3, 5. A sheet metal part is wrapped or coiled
around a core and is welded as illustrated in Figure 1a. The circumferential wall 7
already has openings for the passage of the inlet tubes 31. Subsequently the
insert pieces are axially inserted from both sides into in the circumferential wall 7,
the so-called casing, and the end walls 3, 5 are connected with the casing 7.
The inlet tubes 31 are inserted through these openings until they too protrude
through the corresponding openings in the support walls 23.
Subsequently, the inlet tubes 31 are fastened to the associated support walls
23, more precisely, by mechanical deformation. For this purpose, a tool, e.g. a
kind of embossing tool or rotating rolls, penetrate the interior of the corresponding
tube 31. The tube 31 is plastically deformed e.g. along its entire tube
circumference in the region of the sleeve-like edge 33 in outward direction under
formation of a groove, with the edge 33 being deformed. In this way, the tube 31
and the support wall 23 are axially and radially pressed and connected with each
other in the manner of an interlocking and frictional fit.
The groove between the two deformed portions has the reference symbol 51.
In Figure 4, it is easy to identify the bulge-like protrusion 53 which has formed in
the support wall 23.
Instead of a closed surrounding groove 51 the tube 31 and the support wall
23 can also be pressed onto each other in segments, as illustrated in Figure 5.
Here, the tube 31 has been pressed outside only at a few sections 55 which are
circumferentially spaced from each other, with the formation of bulges 53 on the
For the purpose of a radial locking it would also be possible to provide a
press-fit between the two parts.
Figure 6 schematically shows an alternative to the deformation shown in
Figures 4 and 5. The difference to the embodiments of Figures 4 and 5 is that the
tube 31, as seen in axial direction, is plastically deformed outwardly, i.e. in radial
direction, in front of and behind the edge 33. In this process, the edge 33 is not
deformed. The resultant bulges lock the edge 33 in axial direction. It is also
possible to deform the tube 31 only in sections, similarly as shown in Figure 5, in
front of and behind the edge 33.
Another possibility for deformation is to flange the free end part of the tube 31,
which extends through the opening, in an outward direction, resulting in a locking
in axial direction.
The embodiment according to Figure 3 essentially corresponds to the
embodiment shown in the Figures which have been described so far, so that in
the following only the differences need be discussed. Parts with the same
function receive the reference symbols which already have been introduced
This transverse exhaust gas muffler is also provided with a coiled
circumferential wall 7. The muffler is a one-pass model and has only one central
inlet tube 31. This inlet tube 31 is welded, as with the already mentioned example
embodiments, to the circumferential wall 7 and protrudes through the latter and
through the support wall 23. Downstream of the support wall 23 the tube 31 is
expanded at the circumference at several sections 55 which are spaced from
each other. A sleeve-like edge 33 may be dispensed with here, which incidentally
also applies for the embodiment mentioned before. The central insert piece in the
muffler interior consists of the end walls 11, 19, the support wall 23 as well as the
connection tubes or corresponding connection bars 25. This insert piece is
positioned in the axial direction A only by the inlet tube 31. The outlet tube 39
protrudes with a slide fit through the end wall 19. Due to this design, smaller
forces will be exerted on the walls during heating and cooling of the muffler and,
as a consequence, all individual parts are subject to smaller strains, which also
applies to the weld seams for the fastening of the tubes 21, 31, 39, 41.
It would also be possible that - instead of the inlet tube 31 - the outlet tubes
21, 39 pass through the circumferential wall 7.
The support wall 23 is preferably aligned at right angles to the longitudinal
axis X of the inlet tube 31 which passes through it.
1. A vehicle muffler, comprising
opposite outer end walls (3, 5),
a closed outer circumferential wall (7) formed by coiling a sheet metal part,
at least one muffler insert,
at least one inlet tube (31) and
at least one outlet tube (21, 39),
characterized in that
one of the tubes (31) extends through the circumferential wall (7) into the
muffler interior and is fastened to the circumferential wall (7) and the insert piece.
2. The vehicle muffler according to claim 1, characterized in that the tube
(31) which extends through the circumferential wall (7) is fastened to the insert
piece by mechanical deformation.
3. The vehicle muffler according to claim 2, characterized in that the tube
(31) which extends through the circumferential wall (7) is pressed onto the insert
4. The vehicle muffler according to any of the preceding claims,
characterized in that the tube (31) which extends through the circumferential wall
(7) is connected with the insert piece along the entire circumference of the tube.
5. The vehicle muffler according to any of the preceding claims,
characterized in that the tube (31) which extends through the circumferential wall
(7) is mechanically deformed starting from the tube interior, in order to be
connected with the insert piece.
6. The vehicle muffler according to any of the preceding claims,
characterized in that the insert piece has at least,one inner end wall (11, 13, 17,
19) for the formation of a chamber and that a support wall (23) is fastened to the
inner end wall (11, 13, 19), onto which the tube (31) extending through the
circumferential wall (7) is arrested.
7. The vehicle muffler according to claim 6, characterized in that the support
wall (23) is situated between two inner end walls (11, 13, 19) to which it is
8. The vehicle muffler according to any of the preceding claims,
characterized in that the insert piece, to which the tube (3) extending through the
circumferential wall (7)' is fastened, is clamped in longitudinal direction (A) of the
muffler solely by the tube (31).
9. The vehicle muffler according to any of the preceding claims,
characterized in that two tubes (31) are provided which protrude through the
circumferential wall (7) into the muffler interior, which are fastened at their free
end pieces to two neighboring insert pieces.
A vehicle muffler, which is structured in a coiled fashion, has a tube (31)
extending through the circumferential wall (7), this tube on the one hand being
welded to the circumferential wall (7) and on the other hand being fastened by
mechanical deformation to a support wall (23) of an inner insert piece.
|Indian Patent Application Number||4810/KOLNP/2007|
|PG Journal Number||49/2011|
|Date of Filing||11-Dec-2007|
|Name of Patentee||EMCON TECHNOLOGIES GERMANY (AUGSBURG) GMBH|
|Applicant Address||BIBERBACHSTRASSE 9, 86154 AUGSBURG|
|PCT International Classification Number||F01N 7/18|
|PCT International Application Number||PCT/EP2006/002888|
|PCT International Filing date||2006-03-30|