DE102005025426A1 - Method for producing exhaust gas-conducting devices - Google Patents

Abstract

One Method for producing exhaust gas-conducting devices, in particular Exhaust gas purification devices, provides that the weight of each insert or the substrate is determined and in dependence on this weight the depositor housed in a matched outer housing (14) and is clamped.

Description

The The invention relates to a method for producing exhaust gas Devices, in particular exhaust gas purification devices, each one Outer casing and have an insert clamped in it.

The exhaust-carrying Devices which are involved in the invention are, for example, mufflers, in particular but emission control devices such as catalytic converters and diesel particulate filters.

In such devices are very sensitive to radial pressure Depositors housed, so far it is predominantly flowed through axially Ceramic substrates provided with an elastic compensating element (e.g. in the form of a mat) are wrapped. These depositors will, if possible, only by radial clamping in the outer housing in the axial and lateral Direction held. In addition is an axial support e.g. possible with a wire mesh ring. With a radial clamping must this big enough be, so while driving by the gas pressure as well as by vibrations no displacement of the insert relative to the outer housing in the axial direction comes. On the other hand, of course, the radial pressure must not be that big that it to destroy the insert comes, in particular for destroying the pressure-sensitive Catalyst substrate or diesel particulate filter substrate.

The Insertion and clamping of the insert in the outer housing is usually done so far either by winding a sheet metal jacket around the insert, through Inserting the inserter into a tube with or without subsequent Calibrate or close of shells. If the applied force is too great, it can destroy the Einlegers, that is in the case of catalysts of the substrate.

A size Difficulty in the manufacture of emission control devices consists in that between the substrate and the outer housing the elastic compensating element, typically the bearing mat, provided is that for a pressure equalization and a constant bias provides. The disadvantage However, this storage mat is that, after it is compressed, is subject to a certain setting process, one speaks of Relax, so that's over it decreases to the substrate passed pressure. The springback of the outer housing the introduction and terminals leads also to the fact that the initially applied pressure on the substrate and thus the applied clamping force subsides. Continue to take the holding pressure of the bearing mat in operation (for example, by aging). this leads to to that one with regard to the later secure clamping of the substrate in the outer housing for safety's sake, the outer housing still more initial Exert pressure on the inserter leaves, why one goes to the limits of stability for individual substrates.

task The invention is to provide a method which is also in the Depositors for ensures a sufficiently secure clamping in the outer housing with minimal reject rates.

• a) Bestimmen des individuellen Gewicht des Einlegers oder des Substrates,
• b) Ermitteln eines auf das individuelle Gewicht abgestimmten Haltedruckes des Außengehäuses und daraus resultierend einer auf das individuelle Gewicht abgestimmten Geometrie zur Schaffung einer erforderlichen, individuellen, auf den Einleger auszuübenden Klemmkraft und
• c) Montieren und Klemmen des Einlegers in einem, den auf den Einleger abgestimmten Haltedruck bzw. die abgestimmte Geometrie aufweisenden Außengehäuse.

This is achieved by the following process steps:

• a) determining the individual weight of the insert or the substrate,
• b) determining a matched to the individual weight holding pressure of the outer housing and, as a result, tailored to the individual weight geometry to provide a required individual, to be applied to the insert clamping force and
• c) mounting and clamping of the insert in one, the holding pressure matched to the depositor or the outer housing having the tuned geometry.

In the previously known methods, the necessary holding pressure is determined once and adjusted the outer geometry of the housing to obtain this pressure. Alternatively, a constant force is used to deform the outer housing and thus to ensure the desired holding pressure. This is done regardless of the load capacity and individually required holding pressure for each depositor. The invention takes a different approach by first determining the necessary holding force for each individual inserter installed, and then, depending on this load capacity, adjusting the clamping force through the outer housing thereon. The required holding force depends on the mass of the insert and can basically be determined by the following formula: Holding force = mass of the inserter × max. Acceleration during operation + frontal pressure difference × cross-sectional area of the substrate ,

The applied holding force also results from the formula Holding force = coefficient of friction × pressure of an elastic compensating element × clamping surface of the elastic compensating element × operating coefficient (eg for temperature, aging, etc.)

It even more complicated formulas are possible to the required Holding power to determine. The o.g. Formula only considers the physical fundamentals and leads in practice to sufficient results.

The elastic compensation element is usually between depositors and inside of the outer housing clamped. The usual ones Method, the outside diameter of the depositor or the pressure of the compensating element, let the clearly fluctuating weight of the depositor and his disregarded weight tolerance-related coating, so that if necessary to exerted a lot of holding force on the substrate and therefore unnecessarily burdened will or the selected Holding pressure is too low. The substrate weight without coating can be for example a standard automotive catalytic converter fluctuate between 295 and 415 g, with a diameter of 110 mm and a length of Substrate of 125 mm.

at The present invention is for each individual depositor determines the clamping force adapted to it and applies it to it, by a for regarding him tailored to the geometry Exterior housing provided becomes. "Geometry" is called in this Context that form and dimensions tailor-made for the outer housing become. It does not have to necessarily mean that only after Determining the weight of the tailor made Exterior housing made becomes. It is quite possible previously already different outer housing To produce geometries or their individual parts and then the outer housing or to use those parts that are closest to the desired geometry. The geometry of the outer casing should be preferably not exclusively depending be optimized by the weight determined, but also in terms to other data, which will be discussed in more detail below.

to Determining the weight of the insert can be weighed this.

alternative can over a measurement of the outer geometry (e.g., only by measuring the cross-section or diameter of the Einlegers) the weight can be determined. This determination is made for example via the Density calculation or over one so-called assignment matrix. In such an allocation matrix are for different external geometries the assigned weights are stored, so that one without further calculation with the measured external geometry immediately comes to weight.

When Inserts can only the exhaust gas flowed substrate or unit be viewed from substrate and compensating element.

As already mentioned, is preferably between the substrate and the outer housing an elastic Compensation element whose weight can also be determined So that the Geometry of the outer housing may. also depending on the Compensating element determined, i. is tuned to it. Since that elastic compensation element with the substrate form a unit should and is to guard against displacement, the consideration ensures the weight of the compensating element for a more accurate determination the customized outer geometry and clamping force. The weight of the compensating element is usually significantly lower than the weight of the substrate and also with significant lower tolerances. Joint determination of the complete weight the inserter can thus save costs with acceptable error contribute.

to Determination of the individual geometry can according to an advantageous development of the invention on the enclosed with the compensating insert a lateral, in particular radial pressure are exerted. For one certain elastic deformation then becomes the necessary pressure determined, preferably measured. This can be the density of the compensation element determine that then over the weight flows into the determinations of the optimal geometry of the outer housing.

of course is It is also beneficial if the outside dimensions of the unloaded Depositor first and then this data into the determination of individual geometry.

All determined data to determine the geometry of the outer housing fed into a controller, preferably fully automatically by Coupling with the measuring devices. The Control then determines the custom geometry.

According to the preferred Embodiment is the controller coupled simultaneously with the tool, which is the Outer casing on the desired Geometry brings.

The Device produced by the method according to the invention, is according to the preferred embodiment an exhaust gas catalyst or a diesel particulate filter, both with a pressure-sensitive substrate provided as the core of the insert are.

The pressure exerted on the inserter is normally directed radially inwardly, which of course depends on the shape of the outer housing. This does not have to be circular in cross-section, but may also be out of round, for example angular, running.

The casing is especially as a sheet metal housing executed.

The inventive method can on all previously known methods for producing exhaust gas Appliances are applied.

One first method is the so-called winding, in which a plate-shaped sheet metal section wrapped around the insert and then from reaching the predetermined Internal dimensions at its edges attached and closed.

One second method is the calibration, the outside of the circumference of the prefabricated tube is pressed against this to plastically deform and to press against the depositor.

One third method sees a case from several shells in front, pressed against the depositor and then together be attached.

A fourth embodiment provides a so-called stuffing procedure. Here are several cylindrical casing prefabricated with different internal dimensions. In step b) the inside dimension of the housing is determined, which corresponds to the desired Pressure causes. Subsequently can then the housing with the appropriate dimensions used to insert the end face of the insert into the housing. Alternatively, the internal geometry of the housing can be infinitely, individually be matched to the depositor.

According to one simplified embodiment the invention can be provided that in the determination of the individual Weight of the insert or the substrate a categorization is made and assigned one of the corresponding weight category Geometry of the housing is used. this makes possible in certain circumstances, to dispense with weighing the substrates, as these are usually Supplied by the manufacturer already sorted by weight groups (mostly in the categories easy, medium and hard). Before assembly it is generally determined which housing geometry for the substrates The category light, medium and heavy is suitable for a substrate a certain weight class or category a certain geometry be used. Although this simplified procedure does not provide any so optimally adapted casing as in the cases in which each substrate is weighed, but characterized by a great deal of simplification and thus high cost savings.

Further Features and advantages of the invention will become apparent from the following Description and from the following drawings, to the reference is taken.

In show the drawings:

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

2 schematic views of measuring devices used in the method according to the invention,

3 a perspective view of a calibration tool used in the method according to the invention, partly in section,

4 an end view of a device produced by the inventive method, wherein the outer housing is wound,

5 an end view of a device produced by the inventive method with an outer housing made of shells and

6 a schematic diagram showing the alternatively used in the inventive method plug.

In 1 is shown housed in a motor vehicle exhaust-carrying device in the form of a vehicle exhaust gas purification device. The vehicle exhaust purification device is either an exhaust catalyst or a diesel particulate filter or a combination of both.

The core of the exhaust gas purification device is an elongate, cylindrical substrate 10 , which consists for example of a ceramic substrate or a type of wound corrugated cardboard or other catalytic carrier or filter material with or without coating. The substrate 10 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 is from a storage mat 12 surrounded, as an elastic compensation element between the substrate 10 and an outer casing 14 acts. The outer housing 14 is very thin-walled and in particular made of sheet metal. Upstream and downstream are with the outer casing 14 an inflow funnel 16 or a discharge funnel 18 connected.

The substrate 10 forms together with the La germatte 12 a prefabricated unit.

In operation, exhaust gas flows over the inlet funnel 16 frontally into the substrate 10 Finally, leaving the substrate with fewer pollutants leaves 10 on the opposite end, over the outlet funnel 18 leave the cleaning device.

The preparation of the cleaning device will be described below with reference to 2 and 3 explained.

In 2 various measuring stations are shown with which properties of each individual to be installed insert (substrate 10 or his storage mat 12 ) with regard to an optimized, matched clamping force in the housing 14 be determined.

The stations explained below are described in the preferred order of the manufacturing process. It should be emphasized that in each station the substrate 10 alone or as a unit together with the storage mat 12 can be measured. If in the following, therefore, only the depositor is mentioned, it automatically expresses that the substrate 10 alone or alternatively the unit of substrate 10 and storage mat 12 can be measured.

In a first measuring device, the outer diameter or the entire outer geometry (shape and outer dimensions) of the insert by means of preferably non-contact measuring sensors 21 determined. The measuring sensors 21 are with a controller 24 connected, in which the measured values obtained for the depositor are stored.

Subsequently, the weight of the substrate 10 on a balance 23 Certainly, the same with the controller 24 is coupled. Again, the data received in the controller 24 stored.

Alternatively, the weight can be without the scale 23 be extrapolated solely by determining the outer geometry.

As a further alternative to weighing (if the determination of the substrate weight on the outer geometry takes place) or in addition to determining the substrate weight, a measuring device is provided in the mass production before the so-called "Canning", ie the application of the outer housing 14 on the insert, the compliance of each individual insert to be installed and / or the density of the bearing mat 12 be determined. For this purpose, the insert is positioned in the device and by at least one pressure jaws 20 , Preferably three or more circumferentially distributed pressure jaws, radially inwardly increasingly loaded. With the jaws 20 are load cells 22 coupled, which scan the applied force F constantly. The force F can then also be used to determine the pressure acting inwardly on the insert laterally on the circumference.

The force F applied to the insert is steadily increased until a predetermined gap S is reached between the substrate 10 and pressure jaws 20 , During the process of jaws 20 is the point of time or continuously recorded the distance parallel to the pressure. The measuring device is with the controller 24 coupled, the pressure over the density and weight of the bearing mat 12 calculated.

With the determined data over the depositor to be installed becomes in the control 24 a matched to at least the individual weight geometry of the outer housing (preferably taking into account the exact outer dimensions, a settlement factor and the compliance) determined, which by calculation or by comparing with one in the controller 24 filed allocation matrix can be done. The individual geometry is designed to achieve the required, individually tailored to the depositor and exercising clamping force.

The insert is now installed in a next step with its tailor-made outer housing, wherein the tailoring of the outer housing or the use of a correspondingly fitting outer housing can be done in different ways, as in the following with reference to 3 to 6 is explained by way of example.

In 3 a calibration device is shown. This includes numerous circular segment-shaped, radially movable jaws 26 that can close to a ring. Into the inside through the cheeks 26 circumscribed workspace is the circular cylindrical tubular outer housing 14 placed in which the insert is inserted axially. The cheeks 26 are then moved radially inward, with the previously in the control 24 determined values with respect to the geometry of the outer housing 14 be used. That means that through the controller 24 previously determined desired dimensions of the outer housing 14 be through a path-controlled movement of the jaws 26 with simultaneous plastic deformation of the outer housing 14 reached. The prerequisite is, of course, that the insert before deformation almost free of play in the outer housing 14 was positioned or the game was taken into account in the deformation. The through the plastically deformed outer housing 14 pressure applied to the insert corresponds to the desired pressure.

Instead of in 3 shown baking 26 the calibration can also be done by means of rollers, which are laterally pressed against the outer housing with inserter provided therein by the predetermined travel and rotated. Also a so-called pressing is possible in this context, in which the outer housing 14 with insert disposed therein is moved relative to the predetermined travel path against a single roller and then a relative rotation between the roller and the outer housing together with insert, so that the roller presses circumferentially in the outer housing and this deforms plastically inward.

In addition to the calibration can also be a winding of the outer housing 14 done as it is in 4 is simply represented by the finished product. A metal strip is wrapped around the insert. The metal strip then forms the outer casing 14 , The overlapping edges 30 . 32 are welded together, after they have been pushed over one another so far that the inner dimension on the inside of the resulting outer housing 14 the calculated values as previously determined.

When winding the sheet metal for the outer housing 14 weggesteuert or alternatively pressure-controlled or force-controlled deformed.

In the 5 embodiment shown operates with two or more shells 34 . 36 which are pushed together. Again, the shells 34 . 36 path-controlled or pressure-controlled or force-controlled so far pushed into each other until the inner dimensions correspond to the determined dimensions. The bowls 34 . 36 then z. B. welded together, folded or soldered.

6 symbolizes the so-called stopper. In the measuring device, the desired dimensions of the outer housing are determined. Subsequently, a cylindrical, tubular outer housing 14 manufactured with the desired diameter. This calibration can be done in one or more work cycles or in a continuous process (eg rolling). Subsequently, the insert is axially in the selected outer housing 14 stuffed. Of course, corresponding funnel-shaped aids are provided here.

Of course, the bowls can 34 . 36 according to 5 already formed in advance to the desired dimensions, similar to that associated with 6 is described.

To emphasize that that is not intended for experimental purposes, where a single catalyst or diesel particulate filter is made becomes. Rather, the process is just meant for mass production, in the case of each individual substrate, including storage mat or, in the case of silencers of the corresponding depositors, his tailor made Exterior housing receives.

The described method leads to a better quality the manufactured device with low capital investment for the devices.

Claims (13)

Method for producing exhaust-gas-conducting devices, in particular exhaust-gas cleaning devices, each comprising an outer housing ( 14 ) with an insert clamped therein, characterized by the following steps: a) determining the individual weight of the insert or the substrate, b) determining a geometry of the outer housing which is matched to the individual weight ( 14 ) to provide a necessary, individual, to be applied to the insert clamping force and c) mounting and clamping of the insert in one, the geometry matched to the insert outer housing. Method according to claim 1, characterized in that that the Insert is weighed to determine the weight. Method according to claim 1 or 2, characterized that the external geometry the insert is measured and that depending on the thus determined Data determines the geometry of the outer housing becomes. Method according to claim 3, characterized that about the in the measurement of the outer geometry of the insert, the weight of the insert is determined becomes. Method according to claim 4, characterized in that that only over cross section or diameter of the insert whose weight is determined. Method according to one of the preceding claims, characterized in that the insert has a filter effect and / or catalytic effect exhibiting, exhaust-gas-flowed substrate ( 10 ). Method according to one of claims 1 to 5, characterized in that the insert a unit of a filter effect and / or catalytic effect, having exhaust gas flow through substrate ( 10 ) and between substrate ( 10 ) and outer housing ( 14 ) is lying elastic compensating element. Method according to one of the preceding Claims, characterized in that for determining the individual geometry of the outer housing, an inwardly directed pressure is exerted on the insert and a pressure necessary for a certain elastic deformation is determined. Method according to one of the preceding claims, characterized characterized in that the outer casing one is exercised by the weight of the insert or the substrate-dependent closing force. Method according to one of the preceding claims, characterized characterized in that the outer housing is exercised by the weight of the insert or the substrate-dependent closing. Method according to one of the preceding claims, characterized characterized in that Determination of the individual geometry of the outer casing External dimensions of the unloaded Be inlaid. Method according to one of the preceding claims, characterized in that data determined for the depositor are stored in a controller ( 24 ) and that in the controller ( 24 ) the individual geometry of the associated outer housing ( 14 ) is determined. Method according to one of the preceding claims, characterized characterized in that the determination of the individual weight of the depositor or Substrates a categorization is made and one of the corresponding Weight category associated with the geometry of the housing is used.