EP1774146A1

EP1774146A1 - Device for purifying exhaust gases of a motor vehicle and method for the production thereof

Info

Publication number: EP1774146A1
Application number: EP05767867A
Authority: EP
Inventors: Erich Forster; Peter Kroner; Otto Steinhauser
Original assignee: ArvinMeritor Emissions Technologies GmbH
Current assignee: Faurecia Emissions Control Technologies Germany GmbH
Priority date: 2004-08-03
Filing date: 2005-07-28
Publication date: 2007-04-18
Also published as: US20080093421A1; US7662204B2; DE102004037480A1; KR100861737B1; WO2006015730A1; CN101010496A; KR20070038162A

Abstract

The invention relates to a device for purifying exhaust gases of a motor vehicle and to a method for the production thereof, wherein said device for purifying exhaust gases of a motor vehicle comprises a multi-part external housing (10) provided with a tube (12) and front funnel-shaped walls (14). Said tube (12) and the front walls (14) are fitted into each other and soldered or welded with each other.

Description

A vehicle exhaust gas purification device and method of manufacturing the same

The invention relates to a vehicle exhaust gas purification device, comprising a multi-part outer housing having a tube formed by a circumferential jacket portion and provided at the axial ends of the tube end walls with a

Inlet and has an outlet, and one housed in the outer housing

Filter body through which the exhaust gas flows and cleans it.

Such vehicle exhaust gas purification devices are, for example, catalysts or soot filters. The filter bodies are e.g. formed by bonded together, extruded, one-piece, monolithic single body, in particular of SiC material. The end walls of the outer housing have funnel sections widening towards the tube, to which a radial, annular section adjoins. To a filter body inside the device, an insulation or swelling mat and then wrapped around the mat, a metal jacket. This metal jacket is made by a longitudinal weld to a pipe. At the two axial ends of the tube then the end walls are attached, wherein the end faces of the tube abut axially against the radial portions and the radial portions projecting outwardly relative to the pipe still something. In this projecting area, the end walls are finally welded to the pipe.

The weld between end walls and pipe is a so-called burn-off seam. Great process engineering efforts must be made so that this burned seam withstands the required bending fatigue strength. In addition, the dimensions and geometries of the axial ends of the tubes and the über¬ standing radial portion of each end wall must be precisely adhered to the creation of a qualitatively constant seam. Otherwise, the radial section on the circumference would be more or less strong projecting towards the tube, which would lead to an uneven weld quality along the circumference.

The invention provides a vehicle exhaust gas purification device that is easier to manufacture with on average higher quality. In addition, a method for producing the vehicle exhaust gas purification device according to the invention is to be specified.

In a vehicle exhaust gas purification device of the type mentioned is provided for this purpose that at least one end wall has a deformed, angled towards the tube, substantially cylindrical shell approach on which the tube rests in the radial direction. The tube and at least one end wall, preferably both, are inserted axially into one another and then lie radially against each other, thus positioning each other. This eliminates the previously expensive positioning between end walls and pipe. This results in a higher process reliability for the subsequent welding or soldering. Due to the changed geometry results in a more homogeneous power flow, and the notch effect of the weld deleted by their other position.

The device according to the invention is suitable not only for the connection of circular cylindrical tubes with the end walls, but also deviating from it geometries, such as so-called triovalen pipes. These are largely triangular, with strongly rounded corners, which instead of the flat sides of the triangle and a large curvature having pages may be provided.

Another advantage which is achieved by the invention is the very precisely adjustable axial compression of a wire knit ring, which hitherto in the region of the inner edge between the associated end wall and the

Filter body was clamped axially. Due to the axial telescoping of tube and end walls, the axial preload force can be adjusted exactly.

The seam of the end wall to the tube has much lower tolerances than in the prior art, in which a Abbrandnaht was provided. In the state The technique is problematic especially the non-uniform contour of the tube formed by winding, which does not allow exactly predeterminable and consistent position relative to the end walls.

By nesting also gaps between pipe and end wall can be easier to avoid.

The mantle shoulder and / or associated pipe end should be tapered radially inward toward their axial ends or radially outwardly expanded to form an insertion chamfer for the axial mating of mantle neck and pipe. As a result, the assembly can be facilitated.

This insertion be the easiest way not by machining, but by plastic deformation of the mantle attachment and / or the zuge¬ arranged pipe end generated.

The inside part (pipe end or jacket approach) is retracted according to the preferred embodiment further radially inward, compared to the tube center. As a result of this narrowing, the inner part protects the so-called bearing mat, which is wound around the filter body, against excessive erosion and the effect of heat.

In addition, it is provided according to an embodiment that with the

Mantelansatz trained end wall or end walls has a pipe widening funnel portion (inflow or outflow) and a pipe towards this subsequent radial section has. The jacket approach then connects to the radial section.

The jacket approach is formed by deep drawing and subsequent axial trimming. Only in the following step is the trimmed edge plastically deformed radially inward, which is also called retraction. The resulting advantages will be erläu¬ tert later with reference to the drawings. A particularly preferred embodiment with regard to high Prozeß¬ safety and easy, easy installation of the outer housing is obtained when an axially acting latching connection is provided between the pipe and shell approach. This latching connection is preferably used for pre-assembly fixation between pipe and mantle attachment. This means that the end walls and the tube are axially inserted into one another, and the axial positioning is achieved by the latching connection. There is no additional tool for exact positioning of the parts to each other for the subsequent welding or soldering necessary. End wall or end walls and pipe are already aligned correctly, both axially by the locking connection and radially through the connector. Thus, overall, the tool costs for the assembly of pipe and Stirn¬ walls and for the support during the subsequent welding or Löt¬ process can be reduced.

The latching connection is e.g. formed by a recess and at least one projecting into the recess projection on the pipe or on the mantle. The indentation and the projection are produced simply by plastic deformation of the corresponding parts.

It may be provided, for example, a circumferential projection. In addition, it would also be conceivable to provide a plurality of circumferentially spaced projections, which possibly facilitates the axial nesting of tube and end walls.

The method according to the invention for producing the explained vehicle exhaust gas purification device provides the following steps:

a) the tube and at least one end wall are axially inserted into one another and

b) the pipe and the end wall are joined together by welding or brazing. As already explained, this results in a higher process reliability and lower quality fluctuations of the weld.

By deep drawing the end wall of the funnel section is formed.

The jacket approach is preferably formed by edge-side deep drawing of the end wall, wherein projecting radially outwardly extending flange from the shell approach to the free edge. This flange is usually used to clamp the end wall in the thermoforming tool edge. On the

Deep drawing follows the separation of the flange.

This separation should be done inwardly prior to forming the edge resulting from the separation so that the end wall can be made within narrower axial tolerances.

As already mentioned, the tube and the end wall can be locked in place when being nested into one another and thereby axially positioned.

Further features and advantages of the invention will become apparent from the following description and from the following drawings, to which reference is made. In the drawings show:

FIG. 1 shows a longitudinal sectional view through a first embodiment of the vehicle exhaust gas purification device according to the invention,

FIG. 2 shows a cross-sectional view through the device along the line H-II in FIG. 1,

FIG. 3 is an enlarged view of the area indicated by X in FIG. 1,

FIG. 4 shows the region shown in FIG. 3 in a somewhat modified embodiment,

FIG. 5 shows the region shown in FIG. 3 in a further modified embodiment, FIG. 6 shows the device in the region of the corner joint shown in FIG. 3 in various method steps,

- Figure 7 shows a half section through a further embodiment of the inventive device and

- Figure 8 is a plan view of the tube in Figure 7, wherein only one half is shown.

1 shows a vehicle exhaust gas purification device is shown, which is housed in the exhaust system. The device has a 3-part outer housing 10 with a longitudinally welded from a metal sheet, a circumferential jacket forming tube 12 and attached to the open end faces of the tube 12 end walls 14. Inside the outer housing 10 is a filter body 16 in the form of a monolithic Dieselrußfilters or a Catalyst accommodated, passes through the exhaust gas (see arrows). To the filter body 16, an insulating or swelling mat 18 is wound, through which the filter body 16 is mounted frictionally in the outer housing 10. The mat 18 also serves to compensate for tolerances as well as the limitation of the biasing force applied to the filter body 16 by the outer housing 10.

The filter body 16 and the tube 12 each have a deviating from the circular outer geometry, which is defined by three flat or not curved portions 20 and three relatively strongly curved, the sections 20 connecting portions 22 (Figure 2).

In Figure 2 is also good to see that the tube 12 is formed by a wound around the filter body 16 and the mat 18 sheet metal, which is circumferentially closed at its outer longitudinal edge 24 by welding.

The two end walls 14 are made by deep drawing and each have a funnel section 26 which widens toward the tube 12 and forms an inlet 28 or outlet 30 for incoming or outgoing exhaust gas. Each funnel section 26 is adjoined by a radial section 32 towards the tube 12. At the radial portion 32 then adjacent to the pipe 12 angled, cylindrical mantle projection 34, with which the end walls 14 'are inserted into the interior of the tube 12 and with which they rest in the radial direction on the tube 12.

As can be seen in Figure 3, the jacket extension 34 is retracted to the free edge 36 inwardly, so that the inner side 38 projects further inward than the inner side 40 of the tube 12 in the region of the tube center. The tube 12, in turn, widens slightly radially outward toward its free axial end in region 42.

As a result, both the tube 12 and the jacket extension 34 has a

Insertion bevel, which facilitate the axial mating of the end wall 14 and the tube 12. Due to the free edge 36 of the jacket projection 34 pulled inwards by plastic deformation, the annular gap 44 between the outer circumference of the filter body 16 and the inside of the outer housing 10 (in this case the inner side 40) is reduced. This results in a lower mass flow of hot gas through the annular gap 44 and thus both lower bypass currents and a lower thermal load of the mat 18th

Optionally, as shown in Figure 3, a wire knit ring 46 can be clamped axially between the radial portion 32 and the end wall 50 of the filter body 16, which further reduces the bypass flow and axially clamps the filter body 16.

As can be seen in Figure 3, the tube 12 has a smaller wall thickness than the end wall 14. The tube 12 and the end walls 14 are welded or soldered at the axial end of the tube along the entire circumference. The corresponding weld bears the reference numeral 48.

The embodiment according to FIG. 4 corresponds essentially to that just described, so that functionally identical parts correspond to the reference elements already introduced. and in the following only the differences have to be dealt with.

Also in this embodiment, at least the end wall 14 shown is inserted into the tube 12. The radial portion 32 is hardly formed, so that the funnel portion 26 merges almost immediately into the mantle 34. In contrast to the flat contact of the jacket projection 34 on the inside of the tube 12 according to FIG. 3, in this embodiment only a linear point contact is actually present.

The jacket projection 34 ends upstream of the end wall 50 of the filter body 16 and radially inwardly of its outer circumference 52. Also in this embodiment, the free edge 36 of the jacket projection 34 is drawn inwardly, in the form of an arc in cross-section. By this design, the flow is directed to the end wall 50, and there is a small bypass flow in the annular gap 44. In contrast to the aforementioned embodiment, although the mantle projection 34 has a chamfer, but not the tube 12, which at its axial ends obliquely radially extends inwardly to thereby reduce the annular gap 44 thereby.

In the embodiment shown in Figure 5, the tube 12 is also drawn radially obliquely inward at its axial end, but the end wall 14 is placed on the tube 12, with its region 42 substantially linear on the inside of the slightly outwardly projecting jacket approach

34 is present.

The manner of producing the end walls 14 in the region of the jacket projection is briefly explained below with reference to FIG. The originally flat sheet metal is provided with an opening and clamped in the deep drawing tool along its outer edge (flange 56) and then deep-drawn. This results in a kind of step between the jacket projection 34 and the radial section 32 and the subsequent funnel section 26. In the next step, the flange 56 is separated in the region of the outer circumference of the jacket projection 34. The cutting line is designated 58. Subsequently, the free edge 36 formed by the trimming is deformed in the direction of arrow inwards to form the inlet slope. In this transformation, the jacket projection 34 is or can be made slightly tapered in total tapered inwardly. By this method results in a very accurate measure d between the radial portion 32 and the axially outermost end of the free edge 36th

A somewhat modified process, in which the shell extension 34 is not formed with the same during the deep-drawing process, envisages forming a substantially wider flange 56 '. This wider flange 56 is then cut to size along cut line 60. In the next step, the resulting free edge 36 'is bent inwardly by more than 90 °, so that the jacket projection 34 and a certain insertion be created. However, since the material will partially flow when bent over at the tight radii between the skirt 34 and the radial portion 32, i. flowing in the length, the dimension d is very difficult to keep in close tolerances.

In FIGS. 7 and 8, tube 12 and end walls 14 are already pre-assembled in the axial direction by a latching connection 62, 64, which acts in the axial direction, before the weld seams 48 are set. For this purpose, based on the left end of the tube 12, this in the region 42 has a circumferential bead 66 (FIG. 8), which forms an encircling projection 68 on the inside. The Mantel¬ approach 34 has a corresponding groove-shaped recess 70 into which the projection 68 engages when the left end wall 14 is pushed into the tube 12.

In the locking connection 64 at the opposite end radially outwardly pointing point-shaped projections 68 'are formed in the tube 12, which snap into a circumferential recess 70' in the tube end cross-coat extension 34. Another alternative would be that the jacket projection 34 also has complementarily shaped, point-shaped recesses 70 ', whereby in the circumferential direction tube 12 and end wall 14 are aligned with each other. It should be emphasized that the end wall 14 can of course also be an intermediate piece between two filter bodies connected in series.

In addition, so-called double-walled end wall units can be installed by the invention. These are formed into funnels, nested plates, which preferably have a common point of attachment to the tube. After this connection point, however, they have an annular gap between them, which serves for thermal insulation.

Claims

claims

1. vehicle exhaust purification device, with

a multi-part outer housing (10),

which has a pipe (12) formed by a peripheral skirt and end walls (14) provided with an inlet (28) and an outlet (30) at the axial ends of the pipe (12), and

a filter body accommodated in the outer housing (10), through which the exhaust gas flows and which cleans it,

characterized in that

at least one end wall (14) has a deformed, to the tube (12) abge¬ angled, substantially cylindrical mantle projection (34) on which the tube (12) rests in the radial direction.

2. A vehicle exhaust gas purification device according to claim 1, characterized in that the jacket extension (34) and / or the associated end of the tube (12) narrows radially inwardly to their axial ends or radially outwardly widened / is, in order for the axial mating of Shell approach (34) and tube (12) to form an import slope.

3. vehicle exhaust gas purification device according to claim 2, characterized in that the jacket projection (34) and / or the associated pipe end are plastically deformed / is to form the insertion bevel.

4. Vehicle exhaust purification device according to one of the preceding claims, characterized in that the jacket extension (34) or the associated pipe end is retracted in comparison to the center of the tube further radially inwardly.

5. A vehicle exhaust gas purification device according to any one of the preceding claims, characterized in that with the jacket projection (34) ausge¬ formed end wall (14) to the tube (12) towards widening funnel portion (26) and a further to the tube (12 ) has at this subsequent radial portion (32), wherein the mantle approach jacket extension (34) adjoins the radial portion (32).

6. A vehicle exhaust gas purification device according to any one of the preceding claims, characterized in that the jacket approach Mantel approach (34) is formed by deep drawing and subsequent trimming.

7. A vehicle exhaust gas purification device according to claim 6, characterized in that the edge produced by trimming (36) is plastically deformed radially inwardly.

8. Vehicle exhaust gas purification device according to one of the preceding claims, characterized in that between the tube (12) and the jacket extension (34) an axially acting latching connection (62, 64) is provided.

9. A vehicle exhaust gas purification device according to claim 8, characterized in that the latching connection (62, 64) forms a Vormontagefϊxierung between the tube (12) and the jacket extension (34).

10. A vehicle exhaust gas purification device according to claim 8 or 9, characterized in that the latching connection (62, 64) by at least one

Recess (70, 70 ') and at least one in the recess (70, 70') protruding projection (68, 68 ') is formed.

11. A vehicle exhaust gas purification device according to claim 10, characterized in that a circumferential projection (68) is provided.

12. A vehicle exhaust gas purification device according to claim 10, characterized in that a plurality of circumferentially spaced projections (68 ') are provided.

13. Vehicle exhaust gas purification device according to one of the preceding claims, characterized in that the end wall (14) and the tube (12) in the region of the jacket extension (34) are welded or soldered together.

14. A method for producing a vehicle exhaust gas purification device according to one of the preceding claims, characterized by the following steps: a) the tube (12) and at least one end wall (14) are inserted axially into one another and b) the tube (12) and the end wall (14 ) are joined together by welding or soldering.

15. The method according to claim 14, characterized by:

Deep drawing of the end wall (14) to form a funnel portion (26).

16. The method according to claim 14 or 15, characterized by the following steps:

Deep drawing of the end wall (14) for forming the MantelansatzMantelansatzes (34), wherein the MantelansatzMantelansatz (34) from a flange (56) projects radially outwardly and

Separating the flange (56).

17. The method according to claim 16, characterized by the following step:

Forming the edge (36) of the jacket projection (34) formed after the separation to the inside.

18. The method according to any one of claims 14 to 17, characterized by the following step:

Locking of the tube (12) and the end wall (14) when nesting.