EP1882089B1 - Method for producing an exhaust-carrying device - Google Patents

Abstract

The invention relates to a method for producing an exhaust-carrying device which comprises at least one insert and one cylindrical casing. The inventive method comprises the following steps: introducing the insert into the casing and applying radial forces using gripping jaws (18) that press against the peripheral surface of the casing, said gripping jaws three-dimensionally deforming the casing inward, thereby gripping the insert in the casing. The gripping jaws (18) are configured and provided with edges (20) in such a manner that marking lines are produced in the casing. Said lines discontinuously extend across the section of the casing in which the insert is arranged and in parallel to the axis of the casing.

Description

The invention relates to a method for producing an exhaust gas-carrying device, comprising at least one insert and a cylindrical outer housing, comprising the steps of: inserting the insert into the outer housing and applying radial forces by means of pressing against the outer peripheral surface of the outer housing clamping jaws, the plastic housing deform inwards to clamp the insert in the outer housing. The invention also relates to an exhaust gas-carrying device, with at least one insert and a plastically deformed cylindrical outer housing.

Such a method and such an exhaust gas-conducting device are known from the prior art (see, for example EP 0 982 480 A2 ), wherein it can be, for example, a catalyst, a diesel particulate filter or a silencer of a motor vehicle in the exhaust gas-carrying device.

FIG. 1 shows a tool that is commonly used to clamp an insert, which is formed in the case of a motor vehicle catalytic converter 10, for example, by a ceramic substrate 12 and an insulating mat 14 in an outer housing 16. The tool has a plurality of clamping jaws 18, which are arranged around the substrate 12, the insulating mat 14 and the outer housing 16. Subsequently, the clamping jaws 18 are pressed radially inwards, toward the outer housing 16, whereby radial forces act on the outer peripheral surface of the outer housing 16. As a result, the outer housing 16 is plastically deformed inwardly and thus clamped the substrate 12 with the insulating mat 14 in the outer housing 16. The jaws 18 have in a fully merged state in the form of a hollow cylinder whose inner diameter corresponds to the desired outer diameter of the finished catalyst 10 just.

A disadvantage of the described method for producing an exhaust gas-carrying device is that 18 mark lines in the outer housing 16 arise by the merging of the jaws, which are adjacent to the contact surfaces of the inner longitudinal edges 20 of the jaws 18 with the outer housing 16 and by the partial impressions of the outer housing 16 arise. These inner longitudinal edges 20 extend in the jaws 18 according to the prior art straight and parallel to the longitudinal axis L of the outer housing 16, as particularly well in FIG. 2 can be seen, showing the unwound inner surface of the tool according to the prior art.

When forming, it may come to sinking, also called denting, a portion of the outer housing 16. This danger exists in particular in outer casings which have no circular but, for example, an elliptical or an approximately triangular cross-section.

The object of the invention is therefore to provide a method of the type mentioned, by means of which an exhaust gas-conducting device can be produced, whose outer housing has a higher stability during the forming.

According to the invention, it is provided in a method of the type mentioned above that the jaws are formed and have such edges that marking lines are formed in the outer housing, which do not extend over the portion of the outer housing in which the insert is arranged, not axially parallel to the outer housing. The inventive method results in an exhaust gas-conducting device of the type mentioned, in which the outer housing has marking lines that do not extend over the portion of the outer housing in which the insert is arranged, not axially parallel to the outer housing. The resulting marking lines thus have one or more sections which are not parallel to the axis of the outer housing, which is also meant that they comprise several axially parallel sections, but which offset from one another. In any case, the marking lines are not both continuous as well as continuously paraxial, whereby the susceptibility of the outer housing against sagging or denting is significantly reduced.

Due to the special alignment of the marking lines, the forces applied when deforming the housing are introduced more uniformly into the outer housing and distributed in the outer housing. The inventive method is also characterized by its simple and cost-effective usability, since ideally only the jaws 18 must be replaced in the method according to the prior art, the other production facilities can be maintained.

According to a preferred embodiment, the marking lines have at least one section extending obliquely to the longitudinal axis of the outer housing, whereby the outer housing is more stable during forming.

The marking lines preferably have at least one axially parallel section and at least one section extending transversely to the longitudinal axis of the outer housing and are thereby caused by clamping jaws which can be manufactured comparatively easily.

According to a further embodiment, a plurality of axially successively arranged groups of marking lines extending over partial lengths are formed in the outer housing, wherein the marking lines of successive groups are arranged offset from one another in the circumferential direction. This is z. B. achieved by the use of jaws having a plurality of axially successively arranged sections, each having axially parallel to the outer housing extending longitudinal edges, wherein each two successive sections are arranged offset from one another. Such trained jaws are characterized by their particularly simple and therefore cost-effective manufacturability.

Preferably, the opposite longitudinal edges of each jaw parallel to each other, wherein advantageously all jaws have the same geometries and dimensions. This gives you a set of jaws that are interchangeable with each other, which, for example, can easily keep spare parts in stock.

• Figur 1 eine Perspektivansicht eines Werkzeugs zur Herstellung einer abgasführenden Vorrichtung gemäß dem Stand der Technik, teilweise im Schnitt;
• Figur 2 eine Draufsicht auf die abgewickelte innere Mantelfläche des Werkzeugs gemäß dem Stand der Technik nach Figur 1;
• Figur 3 eine Schnittansicht durch eine durch das erfindungsgemäße Verfahren hergestellte abgasführende Vorrichtung;
• Figur 4 eine Draufsicht auf die abgewickelte innere Mantelfläche eines Werkzeugs zur Durchführung des erfindungsgemäßen Verfahrens, die auch der Draufsicht eines abgewickelten Außengehäuses entspricht; und
• die Figuren 5a bis 5h schematische Ansichten verschiedener Ausführungsformen von Markierungslinien, die bei Durchführung des erfindungsgemäßen Verfahrens im Außengehäuse der abgasführenden Vorrichtung entstehen.

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 this show:

• FIG. 1 a perspective view of a tool for producing a exhaust gas-conducting device according to the prior art, partially in section;
• FIG. 2 a plan view of the unwound inner circumferential surface of the tool according to the prior art after FIG. 1 ;
• FIG. 3 a sectional view through an exhaust gas-producing device produced by the inventive method;
• FIG. 4 a plan view of the developed inner circumferential surface of a tool for carrying out the method according to the invention, which also corresponds to the plan view of a developed outer casing; and
• the FIGS. 5a to 5h schematic views of various embodiments of marking lines that arise in carrying out the method according to the invention in the outer casing of the exhaust gas-conducting device.

FIG. 3 shows a sectional view through an exhaust gas-carrying device in the form of a catalyst 10, which was prepared by the method according to the invention. Also, the outer housing 16 of the catalyst 10 has, as known from the prior art, a plurality of marking lines 22, which arise from the fact that the outer housing 16 is deformed only in the region of the jaws 18 inwardly and not between the opposite longitudinal edges 20 of adjacent jaws 18th However, the outwardly projecting marking lines 22 do not run continuously parallel to the axis Outer housing 16, whereby the outer housing 16 is less prone to sagging or denting during forming.

A possible tool for clamping the ceramic substrate 12 and the insulating mat 14 in the outer housing 16 is in FIG. 4 shown. Again, the tool is a hollow cylinder consisting of a plurality of jaws 18, compared to the prior art (see FIG. 2 ) run in the jaws 18 according to the invention, the longitudinal edges 20 is not continuous axially parallel to the outer housing 16. The jaws 18 according to the in FIG. 4 The illustrated embodiment of the invention comprise an upper portion 18a, a middle portion 18b, and a lower portion 18c, with the middle portion 18b of each jaw being offset leftward by about half a jaw width from the upper portion 18a and the lower portion 18c.

The opposite longitudinal edges 20 of each clamping jaw 18 extend parallel to one another over the entire length of the clamping jaw 18, and all the clamping jaws 18 have the same geometry and the same dimensions, ie they engage seamlessly in the merged state.

By using the in FIG. 4 illustrated jaws 18 in the manufacture of an exhaust gas-conducting device formed in the outer housing 16 a plurality of mutually parallel bead-like marking lines 22a, which extend crenellated along the longitudinal axis L of the outer housing 16 and substantially the in FIG. 5a have shown shape.

In addition to in the FIG. 4 Of course, it is also conceivable that each individual jaw 18 consists of three separate sections 18a, 18b and 18c, which are arranged offset in the circumferential direction of the outer housing 16 to one another. When using such trained jaws formed in the outer housing 16 a plurality of axially successively arranged groups of extending over part lengths marking lines, wherein the marking lines successive groups are arranged offset in the circumferential direction to each other ( FIG. 5b ).

Of course, the jaws 18 may also have any other configuration that leads to the formation of non-continuous axially parallel to the outer housing 16 extending marking lines 22, some of which are further examples in the FIGS. 5c to 5h are shown. Again, the shape of the respective longitudinal edges 20 of the jaws 18 corresponds to the shape of the resulting marking lines.

Thus, marking lines 22c are conceivable which have a plurality of axially parallel and a plurality of obliquely extending to the longitudinal axis L of the outer housing sections. It is also possible to form the clamping jaws 18 such that continuously extending obliquely to the longitudinal axis L of the outer housing marking lines. These may be diagonal marking lines 22d or tapered marking lines 22e.

The Figures 5f to 5h also show arcuate, approximately S-hibrmig running and meandering marking lines 22f to 22h.

All shown possible marking lines 22a to 22h have in common that they do not run continuously axially parallel to the outer casing of the exhaust gas-conducting device.

Claims (11)

1. A method of producing an exhaust gas-carrying device, comprising at least one insert piece and a cylindrical outer housing (16), the method comprising the following steps:

   - introducing the insert piece into the outer housing (16), and

   - applying radial forces by means of clamping jaws (18) which press against the outer peripheral surface of the outer housing (16) and plastically deform the outer housing (16) inwards in order to clamp the insert piece in the outer housing (16),

   characterized in that the clamping jaws (18) are configured such and have edges (20) such that marking lines (22) are formed in the outer housing (16) which do not continuously extend axially parallel to the outer housing (16) along that portion of the outer housing (16) in which the insert piece is arranged.
2. The method according to claim 1, characterized in that the marking lines (22c; 22d; 22e) have at least one portion which extends obliquely to the longitudinal axis (L) of the outer housing (16).
3. The method according to claim 1 or claim 2, characterized in that the marking lines (22a; 22c) have at least one axially parallel portion and at least one portion which extends transversely to the longitudinal axis (L) of the outer housing (16).
4. The method according to any of the preceding claims, characterized in that the marking lines (22a) extend along the longitudinal axis (L) in a crenellated shape.
5. The method according to any of the preceding claims, characterized in that the marking lines (22f) extend in a curved shape with respect to the longitudinal axis (L).
6. The method according to any of the preceding claims, characterized in that the marking lines (22g) extend approximately in an S-shape.
7. The method according to any of the preceding claims, characterized in that the marking lines (22h) extend in a meander shape.
8. The method according to any of the preceding claims, characterized in that several axially consecutively arranged groups of marking lines (22b), extending along partial lengths, are formed in the outer housing (16), with the marking lines of successive groups being arranged offset relative to each other in the peripheral direction.
9. The method according to any of the preceding claims, characterized in that the opposite longitudinal edges (20) of each clamping jaw (18) extend parallel to each other.
10. The method according to any of the preceding claims, characterized in that all clamping jaws (18) have identical geometries and dimensions.
11. An exhaust gas-carrying device, comprising at least one insert piece and a plastically deformed cylindrical outer housing (16), characterized in that the outer housing (16) has marking lines (22) which do not continuously extend axially parallel to the outer housing (16) along that portion of the outer housing (16) in which the insert piece is arranged.

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