DE102019131526A1 - Method for fastening a metallic pipe in an opening of a plastic housing in an exhaust system of a vehicle, exhaust system and vehicle - Google Patents

Abstract

A method for fastening a metallic tube in an opening of a plastic housing comprises the following steps: a) providing a plastic housing (18) with an opening (36) which has a bead (40) and a metallic tube (20), b) Arranging the tube (20) within the opening (36) of the plastic housing (18), and then c) plastic expansion of the tube (20) such that an outwardly projecting elevation (30) on the tube (20) into the bead (40 ) engages so that the pipe (20) is fastened in the axial direction by a form fit in the opening (36). Furthermore, an exhaust system and a vehicle are shown.

Description

The invention relates to a method for fastening a metallic pipe in an opening of a plastic housing in an exhaust system of a vehicle, to an exhaust system and to a vehicle.

Components made of plastic are increasingly being used in the exhaust system of a vehicle in order to realize a light exhaust system.

However, attaching metallic components to plastic components is a particular challenge.

It is therefore the object of the invention to enable a simple, secure attachment of a metallic tube to a component made of plastic.

1. a) Bereitstellen eines Kunststoffgehäuses, das eine durch eine geschlossen umlaufende Umfangswand definierte Öffnung mit einer zumindest abschnittsweise umfangsmäßig umlaufenden, radial nach innen offenen Sicke hat, und eines metallischen Rohrs, das zumindest in einem Befestigungsabschnitt einen kleineren Querschnitt aufweist als der Querschnitt der Öffnung,
2. b) Anordnen des Rohrs innerhalb der Öffnung des Kunststoffgehäuses, wobei der Befestigungsabschnitt axial im Bereich der Sicke positioniert wird, und, anschließend
3. c) plastisches Aufweiten des Rohrs im Bereich des Befestigungsabschnitts derart, dass eine nach außen vorspringende Erhebung am Rohr in die Sicke eingreift, sodass das Rohr in axialer Richtung durch Formschluss an der Umfangswand befestigt wird.

The object is achieved by a method for fastening a metallic pipe in an opening of a plastic housing in an exhaust line of a vehicle. The procedure consists of the following steps:

1. a) providing a plastic housing which has an opening defined by a closed circumferential wall with an at least partially circumferential, radially inwardly open bead, and a metallic tube which has a smaller cross section than the cross section of the opening at least in one fastening section,
2. b) arranging the tube within the opening of the plastic housing, the fastening section being positioned axially in the region of the bead, and then
3. c) plastic expansion of the pipe in the area of the fastening section in such a way that an outwardly projecting elevation on the pipe engages in the bead, so that the pipe is fastened in the axial direction by a form fit on the circumferential wall.

The invention is based on the basic idea of securing a metallic pipe in a plastic housing in a form-fitting manner by plastically expanding the pipe from the inside. In this case, the metallic tube is fastened in a form-fitting manner in the axial direction by means of an outwardly projecting elevation in a bead of the plastic housing. In this way, a heat treatment for fastening the pipe can be dispensed with and the metallic pipe can be fastened to the plastic housing quickly and with simple means.

The plastic housing in particular forms a loudspeaker box.

Above and below, radial and axial directions refer to the central axis of the opening of the plastic housing or the tube.

The bead in the circumferential wall of the plastic housing and the protruding elevation of the tube can be closed circumferentially. In this way, the metallic tube is attached to the plastic housing in a form-fitting manner over a large area.

One aspect of the invention provides that the outer elevation is produced before the pipe is arranged in the plastic housing. In this way, the pipe can be positioned in a specific position relative to the plastic housing and the elevation can be precisely adapted to the bead in advance without the plastic housing being in the way on the tool side.

In other words, the elevation is a protrusion on the pipe, in particular a protrusion extending in a ring shape. This means that the pipe is widened overall in the area of the previously produced projection so that it migrates into the bead.

Alternatively, the elevation can be formed by the plastic expansion of the pipe in step c), so that the pipe is only deformed very locally.

The elevation is therefore always formed by a shaping of the tube.

• d) Befestigen eines dem Kunststoffgehäuse abgewandten Endes des Rohrs an einem abgasdurchströmten Teil derart, dass das Kunststoffgehäuse fluidisch über das Rohr mit dem abgasdurchströmten Teil verbunden ist.

In one embodiment of the invention, the method has the following further step:

• d) Fastening an end of the pipe facing away from the plastic housing to a part through which exhaust gas flows in such a way that the plastic housing is fluidically connected via the pipe to the part through which exhaust gas flows.

Usually, the pipe is pre-fastened to the plastic housing to create a preassembled unit, so that the plastic housing can simply be fastened to the rest of the exhaust pipe via the pipe during the completion of the exhaust system. In particular, simple replacement of the plastic housing is thus made possible.

The pipe is fastened to the part of the exhaust gas line through which the exhaust gas flows, in particular by welding.

In general, it is also conceivable that the pipe is already a part of the exhaust gas line through which exhaust gas flows, so that the plastic housing is fastened directly to the part of the exhaust gas line through which exhaust gas flows.

In order to expand the tube, a pressing tool can be inserted into the tube which, during the expansion, exerts a force acting radially outward on the tube. In this way the pipe is expanded evenly.

The pressing tool may have an outwardly protruding projection in order to form the elevation on the pipe during the plastic expansion of the pipe.

In order to enable mechanical expansion, the pressing tool can have a conical opening in the axial direction. A mandrel can then be inserted into the opening, which mandrel acts on the projection outward in the radial direction.

In one embodiment of the invention, when the fastening section of the pipe is widened, a support tool also engages on the outside of the pipe on a section of the pipe which is located outside the plastic housing. The tube has a larger cross section in this section than in the fastening section. This ensures that the pipe is only expanded in the fastening section. A force acting radially outward on the section of the pipe on which the support tool rests then only presses the corresponding section against the support tool without expanding the pipe in this section.

For example, the support tool surrounds the pipe completely along the circumference.

In order to ensure a certain positioning of the support tool relative to the press tool, the press tool can have a radial extension which rests against the support tool in the axial direction and acts as an axial stop.

In one embodiment of the invention, a plurality of axially spaced at least partially circumferential beads are provided in the peripheral wall and during the expansion of the tube, a plurality of spaced outwardly projecting elevations penetrate their respectively assigned bead. Thus, the pipe is positively connected to the plastic housing in several areas, so that a very stable connection is created.

The object of the invention is also achieved by an exhaust gas line for a vehicle. The exhaust line has a one-piece metallic pipe and a plastic housing. The plastic housing has an opening which is defined by a circumferentially closed circumferential wall. The circumferential wall has an at least partially circumferential bead. The metallic tube has a fastening section with an outwardly protruding elevation which engages in the bead of the opening so that the tube is fastened in the axial direction by a form fit on the plastic housing.

In other words, the metallic tube is fastened via the elevation in a corresponding bead in the opening by means of a form fit. In this way, a simple fastening of the metallic tube in the opening of the plastic housing is made possible.

The plastic housing is in particular formed in one piece.

In one embodiment of the invention, the plastic housing is a loudspeaker box made of plastic. This allows the resonance chamber of the loudspeaker box to be easily adapted to the specifications of the exhaust system.

For example, the exhaust line is produced using a method explained above, so that the features and advantages of the method described above also result for the exhaust line, and vice versa.

The object is also achieved according to the invention by a vehicle with an exhaust system described above. The features and advantages discussed for the exhaust system also apply to the vehicle and vice versa.

• - 1 eine schematische Seitenansicht eines erfindungsgemäßen Fahrzeugs,
• - 2 eine Draufsicht auf einen Ausschnitt eines erfindungsgemäßen Abgasstrangs gemäß 1,
• - 3 einen Längsschnitt durch ein Rohr und ein Kunststoffgehäuse des Abgasstrangs gemäß 2,
• - 4 eine perspektivische Explosionsansicht des zum Befestigen des Rohrs an dem Kunststoffgehäuse verwendeten Werkzeugs,
• - 5 einen Längsschnitt durch das Rohr und das Kunststoffgehäuse gemäß 3 mit dem Werkzeug gemäß 4,
• - 6 einen Längsschnitt durch das Kunststoffgehäuse und das Rohr gemäß den 3 und 5 im befestigten Zustand, und
• - 7 einen Längsschnitt durch das Kunststoffgehäuse gemäß 3 und eine weitere Ausgestaltung eines Rohrs während des Befestigungsvorgangs des Rohrs am Kunststoffgehäuse.

Further features and advantages of the invention emerge from the following description and from the accompanying drawings, to which reference is made below. In the drawings show:

• - 1 a schematic side view of a vehicle according to the invention,
• - 2 a plan view of a section of an exhaust line according to the invention according to 1 ,
• - 3rd a longitudinal section through a pipe and a plastic housing of the exhaust line according to 2 ,
• - 4th an exploded perspective view of the tool used to attach the tube to the plastic housing,
• - 5 a longitudinal section through the tube and the plastic housing according to 3rd with the tool according to 4th ,
• - 6th a longitudinal section through the plastic housing and the tube according to the 3rd and 5 when fastened, and
• - 7th a longitudinal section through the plastic housing according to 3rd and a further embodiment of a pipe during the process of fastening the pipe to the plastic housing.

1 shows a vehicle 10 in a schematic side view.

The vehicle 10 has an internal combustion engine 12th and an exhaust line 14th . Via an exhaust 16 of the exhaust system 14th are those in the internal combustion engine 12th resulting combustion gases are transported to the outside.

2 shows a plan view also a section of the exhaust line 14th according to 1 .

The exhaust system 14th comprises an exhaust pipe which is composed of a plurality of pipes, where a downstream pipe is denoted 17th wearing. Upstream of that pipe 17th is a connection part, hereinafter referred to as a part through which exhaust gas flows 22nd called, connected. Upstream of this part through which the exhaust gas flows 22nd is then another pipe to the part 22nd fluidically connected. The part through which exhaust gas flows 22nd serves to couple sound from an active sound source in the form of a loudspeaker into the exhaust gas flow. For this reason, the part through which exhaust gas flows 22nd a line going out from the actual exhaust system 23 to which a pipe 20th is coupled. The pipe 20th again stands fluidly with a plastic housing 18th in connection so that the inside of the plastic housing 18th fluidic to the pipe 17th is open.

A loudspeaker (not shown), which is coupled to a controller, is housed in the plastic housing, which serves as a resonator.

Corresponding sound waves generated by the loudspeaker can therefore pass through the pipe 20th in the part through which the exhaust gas flows 22nd coupled to the sound of the combustion engine's combustion gases 12th to reduce, cancel or change by means of interference.

3rd shows a longitudinal section through the pipe 20th and part of the plastic housing 18th . Here are the pipe 20th and the plastic case 18th still shown separately from each other, i.e. before the pipe is attached 20th on the plastic housing 18th .

Besides, the pipe is 20th shown in two different positions. The pipe is in the first position 20th shown with solid lines and in the second position with dashed lines.

The pipe 20th has a fastening section at the end 28 on where the pipe 20th two outwardly projecting elevations already produced by forming 30th Has.

In the embodiment of 3rd run the elevations 30th closed annular along the outer wall of the tube 20th . Any survey 30th is rotationally symmetrical to a central axis 32 of the pipe 20th trained and the two bumps 30th are related to the central axis 32 axially spaced from each other.

Furthermore, the 3rd that pipe 20th in the area of the fastening section 28 a smaller inner diameter 34 has than in one of the fastening portion 28 distant, for example opposite end 35 of the pipe 20th . In 3rd this is indicated by the arrows with the reference number 34 shown.

In other words, the pipe has 20th at the end that is the plastic case 18th is close to a smaller inner diameter 34 than at the end 35 that the plastic case 18th is turned away.

The plastic case 18th has an opening on the outside 36 through a closed circumferential wall 38 is defined.

In the perimeter wall 38 are two beads 40 provided, based on the central axis 32 are circumferentially circumferentially and radially inwardly open.

In other words, are the beads 40 to the central axis 32 open.

Furthermore are the beads 40 spaced apart from one another in the axial direction.

More precisely, the beads point 40 axially the same distance from one another as the elevations 30th .

The pipe 20th is in the opening 36 of the plastic housing 18th attached. For fastening the pipe 20th in the opening 36 of the plastic housing 18th a procedure is provided that is described below based on the 3rd to 6th is explained.

In a first process step, both the pipe 20th as well as the plastic housing 18th provided. The pipe 20th is inserted into the opening with its fastening section 36 introduced.

In the 3rd are both the opening 36 as well as the pipe 20th shown with a round cross-section. Accordingly, the Outside diameter of the pipe 20th smaller than the inside diameter of the opening 36 .

In general, square, oval or any cross-sections are also suitable for the opening 36 and the pipe 20th conceivable.

The pipe 20th will be inside the opening 36 arranged so that the bumps 30th of the pipe 20th axially in the area of the beads 40 the perimeter wall 38 are positioned as in 3rd shown with dashed lines.

Subsequently or before a support tool is used 42 from the outside of the pipe 20th pushed open and then a pressing tool 44 inside the tube 20th used. The support tool 42 and the pressing tool 44 are in a perspective side view in 4th shown.

The support tool 42 includes, for example, tapered jaws that have an opening 46 define whose cross-section corresponds to the cross-section of the pipe 20th in the realm of the end 35 can correspond. The jaws 43 can be pushed more or less deeply into a counter-cone, not shown, so that the clamping jaws from the outside against the outside of the pipe 20th to press.

In the design of the 3rd to 6th points the pipe 20th in the realm of the end 35 the same cross-section as the opening 36 of the plastic housing 18th in an area with no bead 40 is so that the cross section of the opening 46 of the support tool 42 the cross section of the opening 36 corresponds to and greater than that in the fastening section 28 is.

The pressing tool 44 also has jaws 48 that can be pushed radially outwards. This is in 4th represented by corresponding arrows.

In addition, the press tool 44 a support section 49 on, as a radial extension on the jaws 48 is molded.

5 shows the pipe in a longitudinal section 20th that in the opening 36 of the plastic housing 18th is used, and the arrangement of the support tool 42 and the pressing tool 44 on or in the pipe 20th .

The pressing tool 44 lies with the support section 49 on one end face of the support tool 42 so that the support tool 42 over the support section 49 against the plastic housing 18th is pressed. In this way, an axial positioning of the support tool 42 and pressing tool 44 ensured.

It also gets the pipe 20th over the support section 49 relative to the opening 36 positioned because it lies axially on the support section 49 at.

In the next process step, the pipe 20th in the area of the fastening section 28 widened. To this end, the pressing tool 44 also a conical mandrel 50 on the inside of the jaws 48 defined conical opening 52 is introduced, causing the jaws 48 be pressed radially outwards.

As the surveys 30th of the pipe 20th in the area of the beads 40 the opening 36 are arranged, the surveys 30th by the plastic expansion of the pipe 20th in the corresponding beads 40 pressed. This is in 6th shown the that on the peripheral wall 38 of the plastic housing 18th fortified pipe 20th shows in a longitudinal section.

The completion of the expansion is achieved when the jaws 48 also against the inside of the pipe 20th in the section with a larger cross-section, which in turn against the support section 49 presses so that the block is driven.

The cross section of the elevations 30th is preferably complementary on the outside or slightly larger than that of the beads 40 .

The pipe 20th is thereby through form fit in the axial direction on the peripheral wall 38 the opening 36 attached.

After fastening, the inside diameter corresponds 34 of the pipe 20th in the area of the fastening section 28 the inside diameter 34 of the pipe 20th at the opposite end 35 of the pipe 20th .

In the next process step, this will be the plastic housing 18th remote end 35 on the part through which the exhaust gas flows 22nd of the exhaust system 14th attached, for example by welding.

Based on 3rd to 6th previously explained how plastic components (e.g. the plastic housing 18th ) into the exhaust system 14th of the vehicle 10 can be integrated. In this way, there is greater flexibility in the design of the exhaust system 14th enables and the method enables a simple and quick fastening of the pipe 20th in the plastic case 18th .

7th shows a further embodiment of the tube 20th and the pressing tool 44 in a longitudinal section corresponding to the 5 . The configuration essentially corresponds to the configuration set out above, so that only the differences will be discussed below.

In contrast to the design of the 3rd to 6th points the pipe 20th in the fastening section 28 no outwardly protruding bumps 30th on.

Instead, the press tool has 44 corresponding outwardly projecting elevations 56 so that the surveys 30th of the pipe 20th only during the expansion of the pipe 20th are formed.

In the embodiments of the 3rd to 7th are the beads 40 and the surveys 30th circumferentially and there are two beads each 40 or surveys 30th which are axially spaced from one another.

It is also conceivable that the beads 40 or the surveys 30th circumferentially not circulating.

In addition, only one bead can be used 40 or a survey 30th or there can be more than two beads 40 or more than two surveys 30th be provided.

Claims (10)

Method for fastening a metallic pipe in an opening of a plastic housing in an exhaust system of a vehicle by means of the following steps: a) providing a plastic housing (18), in particular a loudspeaker box (24), which has an opening (36) defined by a closed circumferential wall (38) with an at least partially circumferential, radially inwardly open bead (40), and a metallic tube (20) which, at least in one fastening section (28), has a smaller cross section than the cross section of the opening (36), b) arranging the tube (20) within the opening (36) of the plastic housing (18), the fastening section (28) being positioned axially in the region of the bead (40), and then c) plastic expansion of the tube (20) in the area of the fastening section (28) in such a way that an outwardly projecting elevation (30) on the tube (20) engages in the bead (40) so that the tube (20) passes through in the axial direction Form fit on the peripheral wall (38) is attached. Procedure according to Claim 1 , characterized in that the outer elevation (30) is produced before the arrangement of the tube (20) in the plastic housing (18) or that the elevation (30) is formed by the plastic expansion of the tube (20) in step c). Procedure according to Claim 1 or 2 , characterized in that the method comprises the following further step: d) attaching an end (35) of the pipe (20) facing away from the plastic housing (18) to a part (22) through which the exhaust gas flows in such a way that the plastic housing (18) fluidically via the Pipe (20) is connected to the part (22) through which the exhaust gas flows. Method according to one of the preceding claims, characterized in that a pressing tool (44) is inserted into the tube (20) to expand the tube (20) and exerts a force acting radially outward on the tube (20) during the expansion. Procedure according to Claim 4 , characterized in that when the fastening section (28) of the tube (20) is expanded, a support tool (42) additionally engages on the outside of the tube (20) on a section of the tube (20) which is located outside the plastic housing (18), the Tube (20) has a larger cross-section in this section than in the fastening section (28). Method according to one of the preceding claims, characterized in that a plurality of axially spaced at least partially circumferential beads (40) are provided in the circumferential wall (38) and that during the expansion of the tube (20) a plurality of spaced outwardly projecting elevations (30) are created which penetrate into their respective assigned beads (40). Exhaust system for a vehicle, with a one-piece metallic pipe (20) and a plastic housing (18), wherein the plastic housing (18) has an opening (36) which is defined by a circumferentially closed circumferential wall (38) which has an at least partially circumferential bead (40), and wherein the metallic tube (20) has a fastening section (28) with an outwardly projecting elevation (30) which engages in the bead (40) of the opening (36) so that the tube (20) in the axial direction by a form fit on Plastic housing (18) is attached. Exhaust system after Claim 7 , characterized in that the exhaust line (14) with a method according to one of Claims 1 to 6th is made. Exhaust system after Claim 7 or 8th , characterized in that the plastic housing (18) is a loudspeaker box (24) made of plastic. Vehicle with an exhaust line (14) according to one of the Claims 7 to 9 .

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