DE102006041609A1 - Method and tool for producing an exhaust gas-conducting device - Google Patents

Abstract

A method for producing an exhaust gas-conducting device, in particular an exhaust gas purification device (10), provides first to bend a metal sheet into a cylindrical, open jacket (16) in which an insert is positioned. Then, the insert, including jacket (16), is introduced into a working space of a molding tool (24) which is delimited by a plurality of pressure jaws (26, 26 ', 26' ') and the pressure jaws (26, 26', 26 '') with reduction of the working space moved towards each other to an end position, wherein the jacket (16) is tightly wound around the insert. At least in the end position of the pressure jaws (26, 26 ', 26' '), the open ends of the shell (16) form an overlapping area (28) which is at least partially covered by a pressure jaw (26, 26', 26 ''). Finally, the jacket (16) is welded in the overlapping region (28) and the exhaust-gas-conducting device (10) is removed from the molding tool (24). Furthermore, a tool for producing an exhaust gas-carrying device is described.

Description

The The invention relates to a method for producing an exhaust gas-carrying Device, in particular an exhaust gas purification device, the an outer casing with has a depositor clamped in it. Furthermore, the invention relates a tool for producing an exhaust gas-conducting device, in particular an exhaust gas purification device.

Exhaust gas devices For the purposes of the invention are in particular exhaust gas purification devices such as catalysts, particle filters or combinations of both. In such devices are sensitive to radial pressure Depositors housed, which are so far mainly to flowed through axially Ceramic substrate, with an elastic compensation element (also referred to as bearing mat) are wrapped. These depositors become mainly by radial clamping in the outer housing in axial and lateral direction, with additional axial support, e.g. with a wire knit ring, possible is. The clamping must be big enough so that it does not drive when driven by gas pressure or vibration to a shift of the insert relative to the outer housing comes. On the other hand may of course the radial or, more generally, laterally inwardly acting pressure is not so be great that it to destroy the insert comes, in particular for destroying the pressure-sensitive Catalyst substrate or particle filter substrate.

The Insertion and clamping of the insert in the outer housing is done so far, for example by so-called winding. Here, first, a metal jacket by Rolling or bending preformed. Subsequently, the insert becomes laterally inserted into the preformed metal jacket, the metal jacket firmly wrapped around the insert and finally the coat closed, by welding becomes. The winding of the sheet metal jacket is carried out by means of two movable Jaws, between which a band stretches around the Depositor is laying around with coat. This results in the known winding method a longitudinal the scope of uneven pressure on the depositor, among other things, from the position of the jaws depends and especially in thin-walled Substrates for their destruction to lead can.

From the EP 0 665 365 A2 For example, a method is known in which a molding tool having three or more movable mold parts is used to wind a sheet metal jacket around a catalyst substrate which is not circular in cross-section. For this purpose, the mold parts are spaced from each other along the sheet metal jacket. Due to the distances between the mold parts, especially in their "closed" state, you get here even no uniform pressure on the insert.

task The invention is to present a method and a tool, that for a sufficiently secure clamping of the insert in the outer housing at minimum reject rates provides.

According to the invention this is achieved by the following process steps: a sheet becomes a cylindrical, bent coat, and the insert is in the open coat positioned. Subsequently the insert, including the jacket, enters a working space of a molding tool introduced, which is limited by a plurality of pressure jaws, and the Pressure jaws become one another while reducing the working space moved to an end position with the sheath tight around the insert is wound and the open ends of the shell at least in the final position the jaws an overlap area form, which at least partially covered by a pressure pad becomes. After all the jacket will be in the overlap area welded, and the exhaust gas leading Device is removed from the mold. The overlap area Here, in particular, the two edges of the jacket sheet are attributable, i.e. it can also be welded in the region of an edge of the jacket sheet. By Provide several, longitudinal the entire circumference of the shell arranged pressure jaws, the Winding the shell to be moved towards each other, resulting in a even pressure distribution along the Scope. As a result, rejects can be avoided be, especially when clamping sensitive depositors.

According to one first embodiment the jacket is welded in the area of a pressure jaw, the along its length at least one recess for performing a welding device having. Thus, there is just the critical overlap area of the jacket within a jaw, which gives a particularly homogeneous pressure load of the insert results.

alternative The jacket can be welded in the area between two pressure jaws.

There the distance between two pressure jaws in the final position preferably very is low, at least one of the jaws on the other jaw can facing side have at least one indent, through which a welding device led to the coat becomes.

Likewise, it is conceivable to weld the jacket in the region of an end face. In this case, a recess or recess in the or the jaws is not essential; the jaws can (partially) be shorter to the Allow welding.

Of the Coat is preferably initially punctiform inside the mold welded and after removing the device along its entire length to Outer housing closed. In this way you come with a small number of recesses in the mold to carry out the welding device out.

Around one possible even pressure distribution to achieve the distance between two adjacent jaws after moving into the final position advantageous at most twice the sheet thickness of the coat.

The Pressure jaws are preferably pressure and / or position-controlled moved to the final position.

The Pressure jaws can before inserting the insert, including the jacket according to the outer contour of the inserter. This happens especially for one each Series of substrates with uniform contour. Before the obstruction a new series with a different contour are the jaws adjusted accordingly.

The the jacket facing the inner surfaces of the Pressure jaws define in the end position preferably a circular cylindrical Pressing surface for formation a circular cylindrical mantle. This is suitable for clamping of circular in cross-section Substrates. Naturally could also substrates with non-circular Cross section are installed (for example, with oval cross-section or any another geometry), in which case the inner contour of the pressure jaws accordingly is trained.

The Pressure jaw covering the overlap area, can on its the jacket facing inside a recess exhibit. This then compensates for the increased material thickness in the overlapping area. This ensures that the Coat on its side facing the insert a uniform, in particular having circular cylindrical contour.

According to one further embodiment the jaw covering the overlap area, on its the jacket facing inside a lateral stop for one external Edge of the sheet on. The stop serves to fix the welding position; During the movement of the jaws, only the inner sheet is relative to Stop postponed.

At the welding the mold can serve as a mass.

Around to get a stable outer casing should the overlap area in the final position of the jaws be at least 10 mm wide.

The inventive method is preferably carried out in a tool of the type mentioned, with a work space for receiving a depositor and a depositor surrounding jacket, several jaws that limit the working space and are movable from an initial position to an end position, and a welding device, with the coat in an overlap area welded can be, wherein at least one of the pressure jaws the overlap area at least partially covered. Such a tool ensures a uniform pressure distribution along the entire coat.

Further Features and advantages of the invention will become apparent from the following Description of several preferred embodiments with reference to the accompanying drawings. In these show:

1 a longitudinal sectional view through an apparatus produced by the invention in the form of an exhaust gas purification device;

2 schematically the production of a jacket for the exhaust gas purification device;

3 schematically the positioning of a depositor in the open shell;

4 a perspective view of a tool according to the invention, partly in section;

5 a cross section through a tool according to the invention after positioning of the insert including jacket in the working space;

6 a cross section through the tool 5 after closing the pressure jaws;

the 7a to d plan views of the outer surface of tools according to the invention according to various embodiments; and

the 8a and b are frontal views of tools according to further embodiments.

In 1 is an exhaust gas-carrying device accommodated in a motor vehicle in the form of an exhaust gas purification device 10 shown. This is a catalyst, particulate filter or a combination of both. Centerpiece of the emission control device 10 is an elongated, cylindrical substrate 12 , for example, of a ceramic substrate, a kind of wound corrugated cardboard or another kata lytic carrier or filter material with or without coating. The substrate 12 may have a circular cylindrical cross section or a non-circular cross section. For the sake of simplicity, a circular-cylindrical cross-section is shown in the figures. The substrate 12 is from a storage mat 14 surrounded, as an elastic compensation element between the substrate 12 and a thin-walled outer housing made of sheet metal acts. The outer housing comprises a jacket 16 upstream with an inflow funnel 18 and downstream with a discharge funnel 20 connected is. The substrate 12 forms together with the storage mat 14 the so-called depositor.

The production of the exhaust gas purification device 10 will be explained below using the 2 to 6 explained. In a bending device 22 is first a sheet to a cylindrical, open jacket 16 bent, which forms part of the outer housing ( 2 ). Subsequently, the substrate is made 12 and storage mat 14 existing inserts eg laterally in the open coat 16 pushed in, as in 3 is shown. Here, the coat 16 be easily spread.

In a next step, the depositor is including coat 16 into a workroom of a 4 shown molding tool 24 placed. The mold 24 includes numerous circular segment-shaped, radially movable pressure jaws 26 , which limit the working space and can close to a ring having a circular cylindrical Andrückfläche (inside). The jaws 26 are then pressure and / or position-controlled moved radially inward into an end position, previously taking into account the dimensions of the insert and the shell 16 and the desired, to be achieved clamping force of the insert has been set in the outer housing. This reduces the working space when the pressure jaws 26 to move towards each other, and the coat 16 is tightly wrapped around the insert. The open ends of the coat 16 may already form in the starting position ( 5 ), but in any case in the 6 shown end position of the jaws 26 an overlap area 28 to which also both edges 29 of the coat 16 belong. The overlap area 28 is at least partially from a jaw 26 covered, in the example shown even by two pressure jaws, namely in the 6 above arranged pressure jaws 26 ' and 26 '' , The overlap area 28 is in the final position of the jaws 26 at least 10 mm wide.

Like the same 5 and 6 can be seen, has each of the two jaws 26 ' and 26 '' on the other side of the jaw facing side several indentations 30 of which only one can be seen in the figures. These indentations 30 serve, according to the method of the jaws 26 in the final position a welding device 32 to the coat 16 to lead, by means of the coat 16 in the overlap area 28 between the two jaws 26 ' . 26 '' is selectively welded, preferably at two to three welds. When welding, the mold is used 24 as a mass. After removing the device 10 from the mold 24 becomes the coat 16 then closed along its entire length to the outer housing.

7a shows a plan view of the lateral surface of the mold 24 in the area of the jaws 26 ' . 26 '' , The mutually facing indentations 30 form a plurality of recesses for performing the welding device 32 along the length of the jaws 26 ' . 26 '' are arranged. It can, as in 7b shown the indentations 30 the two jaws 26 ' . 26 '' also be executed unequal. Also, the must through the indentations 30 be formed recess not circular. In the versions after the 7a and b is between two jaws 26 ' . 26 '' welded, where one can of course also say that through the indentations 30 also partially in the jaws 26 ' . 26 '' is welded. 7c shows a further alternative embodiment, in which a single jaw 26 a recess 34 to carry out the welding device 32 having. In this embodiment, the jacket 16 in the area of the jaw 26 welded. Of course, along the length of the jaw can also 26 several recesses 34 be provided. In addition, the coat can 16 instead of radially on one or both ends 33 (see. 4 ) are welded. As in 7d is shown, can or can for this purpose in the overlap area 28 arranged pressure jaw (s) 26 front indentations 30 exhibit. Alternatively, the jaws 26 be formed shorter.

Like from the 6 and 7 can be seen, the jaws point 26 after moving into the final position a very small distance from each other, preferably twice the plate thickness of the shell 16 is. Before inserting the insert, including the jacket 16 become the jaws 26 of the mold 24 adjusted according to the outer contour of the insert. In the in the 4 to 6 shown molding tool 24 Show the coat 16 facing inner surfaces of the pressure jaws 26 in the end position on a circular contour.

To compensate for the increased material thickness in the overlapping area 28 can, as in 8th shown the jaw 26 ( 8a ) or the jaws 26 ' and 26 '' ( 8b ) overlapping the overlap area on their coat 16 Trains turned inside a recess 36 exhibit. Through the recess 36 can the pressure load of the substrate 12 equalize. How to continue 8a it can be seen that the overlap area 28 overlapping pressure jaw 26 on its inside a lateral stop 38 have for the outer edge of the sheet. This can be, as in 8b shown, also on the side of a jaw 26 ' Arrange the second jaw 26 '' is facing. The stop 38 ensures that when closing the jaws 26 in the overlap area 28 inside edge 29 of the sheet moves, whereby the welding position is fixed.

Closing the jaws 26 takes place in the case of a circular cylindrical substrate 12 evenly. In a non-circular cross-section substrate 12 can be a different control of the individual jaws 26 be useful to apply a homogeneous pressure on the depositor.

10

exhaust gas purification device

12

substratum

14

bearing mat

16

coat

18

inflow funnel

20

outflow funnel

22

bender

24

mold

26 26 ', 26' '

gibs

28

overlap area

29

margins

30

indentations

32

welder

33

front

34

recesses

36

recess

38

attack

Claims (15)

Method for producing an exhaust-gas-conducting device, in particular an exhaust-gas purification device ( 10 ), which has an outer casing with an insert clamped therein, characterized by the following steps: - a sheet is turned into a cylindrical, open casing ( 16 ), - the insert is placed in an open jacket ( 16 ), - the insert, including the jacket ( 16 ) is placed in a working space of a mold ( 24 ) introduced by a plurality of pressure jaws ( 26 . 26 ' . 26 '' ), - the jaws ( 26 . 26 ' . 26 '' ) are moved towards each other while reducing the working space to an end position, wherein the shell ( 16 ) is wound tightly around the insert and the open ends of the jacket ( 16 ) at least in the end position of the pressure jaws ( 26 . 26 ' . 26 '' ) an overlap area ( 28 ) formed at least partially by a pressure jaw ( 26 . 26 ' . 26 '' ) is covered, - the coat ( 16 ) in the overlap area ( 28 ) and - the exhaust gas carrying device ( 10 ) is the mold ( 24 ). Method according to Claim 1, characterized in that the jacket ( 16 ) in the region of a pressure jaw ( 26 ) is welded, along its length at least one recess ( 34 ) for carrying out a welding device ( 32 ) having. Method according to Claim 1, characterized in that the jacket ( 16 ) in the area between two pressure jaws ( 26 ' . 26 '' ) is welded. Method according to Claim 3, characterized in that at least one of the pressure jaws ( 26 ' . 26 '' ) on the other pressure pad ( 26 ' . 26 '' ) facing side at least one indentation ( 30 ), by which a welding device ( 32 ) to the coat ( 16 ) to be led. Method according to one of the preceding claims, characterized in that the jacket ( 16 ) is welded in the region of an end face. Method according to one of the preceding claims, characterized in that the jacket ( 16 ) inside the mold ( 24 ) initially welded at certain points and closed after removal of the device along its entire length to the outer housing. Method according to one of the preceding claims, characterized in that the distance between two adjacent pressure jaws ( 26 . 26 ' . 26 '' ) after moving to the final position at most twice the metal thickness of the shell ( 16 ) is. Method according to one of the preceding claims, characterized in that the pressure jaws ( 26 . 26 ' . 26 '' ) are moved in the end position in a pressure and / or position-controlled manner. Method according to one of the preceding claims, characterized in that the pressure jaws ( 26 . 26 ' . 26 '' ) before inserting the insert with jacket ( 16 ) are adjusted according to the outer contour of the insert. Method according to one of the preceding claims, characterized in that the jacket ( 16 ) facing inner surfaces of Druckba bridges ( 26 . 26 ' . 26 '' ) Define a circular cylindrical pressure surface in the end position. Method according to one of the preceding claims, characterized in that the pressure jaw ( 26 . 26 ' . 26 '' ) covering the overlap area ( 28 ) covered on her coat ( 16 ) facing inside a recess ( 36 ) having. Method according to one of the preceding claims, characterized in that the pressure jaw ( 26 . 26 ' . 26 '' ) covering the overlap area ( 28 ) covered on her coat ( 16 ) facing inside a lateral stop ( 38 ) for an outer edge of the sheet. Method according to one of the preceding claims, characterized in that the molding tool ( 24 ) serves as a mass during welding. Method according to one of the preceding claims, characterized in that the overlapping area ( 28 ) in the end position of the jaws ( 26 . 26 ' . 26 '' ) is at least 10 mm wide. Tool for producing an exhaust gas-conducting device, in particular an exhaust gas purification device ( 10 ), with a work space for receiving an insert and a jacket surrounding the insert ( 16 ), several jaws ( 26 . 26 ' . 26 '' ), which limit the working space and are movable from an initial position to an end position, and a welding device ( 32 ), with which the coat ( 16 ) in an overlapping area ( 28 ), wherein at least one of the pressure jaws ( 26 . 26 ' . 26 '' ) the overlap area ( 28 ) at least partially covered.