MUFFLER FOR AN EXHAUST SYSTEM AND METHOD FOR MAKING A MUFFLER

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority of German patent application no. 10 2024 119 109.0, filed Jul. 5, 2024, the entire content of which is incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a muffler for an exhaust system, for example, for an internal combustion engine. Furthermore, the present disclosure relates to a method for producing a muffler of this kind.

BACKGROUND

In the production of mufflers, for example, as rear mufflers in exhaust systems of internal combustion engines used as drive assemblies in motor vehicles, muffler tubes guided by muffler walls in the interior of the mufflers are generally connected to the muffler walls through which they pass by forming a material connection by producing a weld seam after the insertion and defined positioning of the muffler tubes in tube passage openings that receive them. There is also a known practice of radially expanding muffler tubes of this kind upstream and downstream of a muffler wall after insertion into a respectively associated tube passage opening in the muffler wall and thus of producing form-locking engagement, acting in the longitudinal direction of the muffler tubes, between the muffler tubes and the muffler walls receiving the tubes.

SUMMARY

It is an object of the disclosure to provide a muffler for an exhaust system and a method for producing a muffler in which components are connected to one another in a simple and stable manner.

According to the disclosure, this problem is solved by a muffler for an exhaust system including:

• • a circumferential wall surrounding a muffler interior,
  • at least one muffler wall, which adjoins the circumferential wall and/or is arranged in the muffler interior,
  • at least one muffler tube, which extends in the direction of a tube axis and passes through a tube passage opening in at least one muffler wall,
  • wherein at least one muffler tube passing through a tube passage opening in a muffler wall is connected to the muffler wall via a bayonet connector.

With a bayonet connector of this kind, a stable, rattle-free connection between a muffler tube and a muffler wall is produced without necessarily requiring additional, for example, material, joining measures. At the same time, the bayonet connector ensures defined positioning of the components connected in this way.

In one component including either the muffler tube or the muffler wall, preferably in the muffler tube, the bayonet connector can include at least one bayonet connector receptacle and, on the other component including either the muffler tube or the muffler wall, preferably on the muffler wall, in association with at least one, preferably each, bayonet connector receptacle, can include a bayonet connector projection.

To further improve the stability of the connection, the bayonet connector can include a plurality of bayonet connector receptacles arranged around the tube axis, preferably at uniform intervals.

For simple production and locking of the connection, the bayonet connector receptacle can include an insertion portion extending substantially in the direction of the tube axis and open in the direction of the tube axis in order to receive a bayonet connector projection, a transitional portion, which adjoins the insertion portion and extends substantially in the circumferential direction, and a locking portion, which adjoins the transitional portion, extends substantially in the direction of the tube axis and is closed in the direction of the tube axis.

To enable the structures required for the bayonet connector to be provided in a muffler tube, the muffler tube can include a first tube portion with a smaller outside dimension, a second tube portion with a larger outside dimension, and a widening portion between the first tube portion and the second tube portion.

To receive a bayonet connector projection, the insertion portion can extend in the widening portion in a direction away from the first tube portion and toward the second tube portion.

To enable the axial length of the widening portion to be used for the insertion of a bayonet connector projection, an insertion end of the insertion portion can be positioned in the widening portion close to the first tube portion. This means that the insertion end is positioned closer to the first tube portion than to the second tube portion, for example, adjoining the first tube portion.

The transitional portion can be positioned in the widening portion close to the second tube portion and/or in the second tube portion. Close to the second tube portion means that the transitional portion is positioned closer to the second tube portion than to the first tube portion, for example, adjoining the second tube portion.

In order to produce form-locking engagement between the muffler wall and the muffler tube in the locked state, a locking end of the locking portion can be positioned in the second tube portion or in the widening portion close to the second tube portion. Here too, close to the second tube portion means that the locking end is positioned closer to the second tube portion than to the first tube portion.

For simple production, the at least one bayonet connector receptacle can include a receiving opening formed in a tube wall of the muffler tube, that is, a receiving opening passing through the wall. This embodiment can advantageously be provided if the bayonet connector is arranged fully in the muffler interior and gas leaks in the region of the bayonet connector are unproblematic.

If gas leaks in the region of the bayonet connector are to be avoided as far as possible, the at least one bayonet connector receptacle can include a receiving recess formed in a tube wall of the muffler tube.

The muffler wall can include an opening rim surrounding the tube passage opening, the rim being bent in the direction of the tube axis. In this case, the bayonet connector projection can include a radially inward-directed formation on the opening rim.

In order to reliably prevent the release of the at least one muffler tube held on a muffler wall via a bayonet connector in the event of vibrations occurring in a vehicle, it is proposed that the at least one muffler tube connected to a muffler wall via a bayonet connector furthermore be connected to the muffler wall by material joining, preferably one or more welds, and/or by force-locking, preferably by radial expansion of the muffler tube in that portion of the muffler tube which passes through the tube passage opening in the muffler wall.

The muffler wall penetrated by a muffler tube and connected to the latter via a bayonet lock can be a partition wall separating two chambers in the muffler interior from one another.

The present disclosure furthermore relates to a method for producing a muffler constructed according to the disclosure, including the following measures:

• • a) supplying at least one component including either the muffler tube or the muffler wall, preferably the muffler tube, having at least one bayonet connector receptacle,
  • b) supplying the other component including either the muffler tube or the muffler wall, preferably the muffler wall, having at least one bayonet connector projection,
  • c) inserting the at least one muffler tube into the tube passage opening in the at least one muffler wall in such a way that each bayonet connector projection on the other component including either the muffler tube or the muffler wall is received in a bayonet connector receptacle of the one component including either the muffler tube or the muffler wall.

To prevent a situation where, after the bayonet connector has been transferred to its locking position during the execution of measure c), this state has subsequently been undone again on account, for example, of the vibrations occurring in a vehicle, it is proposed that furthermore a measure d) is executed for the material joining of the at least one muffler tube to the at least one muffler wall after the execution of measure c), and/or that furthermore a measure e) is executed for the force-locking connection of the at least one muffler tube to the at least one muffler wall after the execution of measure c).

By way of example, measure d) can include the production of at least one weld, that is, the production of one or more spot welds.

Measure e) can include the radial expansion of the at least one muffler tube in its axial region passing through the tube passage opening of the at least one muffler wall.

BRIEF DESCRIPTION OF DRAWINGS

The invention will now be described with reference to the drawings wherein:

FIG. 1 shows a schematic longitudinal section through a muffler;

FIG. 2 shows a muffler wall penetrated by a muffler tube and connected to the latter by a bayonet connector;

FIG. 3 shows the region of the bayonet connector in FIG. 2 in a phase of the production of the connection between the muffler wall and the muffler tube;

FIG. 4 shows an illustration corresponding to FIG. 3 in a later phase of the production of the connection between the muffler wall and the muffler tube; and,

FIG. 5 shows the region of the bayonet connector in a schematic illustration.

DETAILED DESCRIPTION

FIG. 1 shows, in a schematic illustration, one example of a muffler 10 inserted, for example, as a rear muffler in an exhaust system of an internal combustion engine in a vehicle. The muffler 10 includes a circumferential wall 12, which is elongated, for example cylindrically, in the form of a tube in the direction of a muffler axis S and delimits a muffler interior 14 radially with respect to the outside. The muffler 10 furthermore includes a plurality of muffler walls 16, 18, 20, of which those muffler walls 16, 20 which lie at the axial ends of the circumferential wall 12 form end walls which axially delimit the muffler interior 14, while the muffler wall 18 forms a partition wall that divides the muffler interior 14 into two chambers 22, 24.

A muffler tube 26 acting, for example, as an inlet tube passes through the muffler walls 16, 18 and ends in the muffler interior 14 in the region of chamber 24. A muffler tube 28 acting, for example, as an outlet tube passes through the muffler walls 20, 18 and ends in the muffler interior 14 in the region of chamber 22. A muffler tube 30 positioned in the muffler interior 14 passes through the muffler wall 18 separating the two chambers 22, 24 from one another and forms a flow connection between the two chambers 24, 22 and thus also between the two muffler tubes 26, 28.

The connection of a muffler tube to a muffler wall via a bayonet connector, designated in general by 32 below, is explained by way of example below with reference to the muffler tube 30 forming the flow connection between the two chambers 22, 24.

The muffler tube 30 connected or to be connected by the bayonet connector 32 to the muffler wall 18 acting as a partition wall has a first tube portion 34 with a smaller outside dimension, that is, for example, with a smaller outside diameter, which can be seen on the left of the muffler wall 18 in FIG. 2. By way of example, the first tube portion 34 can have a circular and cylindrical geometry. On the right of the muffler wall 18 there is a second tube portion 36 of the muffler tube 30, wherein the second tube portion 36 has a larger outside dimension, that is, for example, a larger outside diameter, than the first tube portion 34. The second tube portion 36 can also have a circular and, for example, cylindrical geometry.

Between the first tube portion 34 and the second tube portion 36 in the direction of a tube axis R there is a widening portion 38 of the muffler tube 30. In the axial region of extent of the widening portion 38, the outside dimension of the muffler tube 30 increases from the outside dimension in the first tube portion 34 to the outside dimension in the second tube portion 36. In a manner corresponding to this increase in the outside dimension, the inside dimension of the muffler tube 30 also increases in the widening portion 38.

A tube passage opening, denoted in general by 40, is formed in the muffler wall 18 in association with the muffler tube 30. To provide the tube passage opening 40, an opening rim 42 bent or extending in the direction of the tube axis R is formed in the muffler wall 18, and, in a manner corresponding to the outer circumferential contour of the muffler tube 30 in the second tube portion 36, the rim likewise has a substantially cylindrical and circular form and provides the tube passage opening 40 substantially via an inside dimension which corresponds to the outside dimension of the muffler tube 30 in the second tube portion 36.

Bayonet connector receptacles 44 are formed in the muffler tube 30 at a plurality of circumferential positions, for example, at uniform intervals with respect to one another. It is possible, for example, for two, three or four such bayonet connector receptacles to be formed along the circumference around the tube axis R, for example. As illustrated schematically in FIG. 5, each bayonet connector receptacle 44 has an insertion portion 46, which extends substantially in the direction of the tube axis R and which extends out of the widening portion 38 into the region of the second tube portion 36. By way of example, an insertion end 48 of the insertion portion 46 can be positioned in such a way in the widening portion 38 that the insertion end 38 lies close to the boundary of the widening portion 38 with the first tube portion 34 or adjacent to the first tube portion 34. The insertion portion 46 could also extend into the first tube portion 34, in which case the insertion end 48 would then be positioned in the first tube portion 34.

Adjoining the insertion portion 46, at its end 50 situated, for example, in the region of the second tube portion 36, is a transitional portion 52 of the bayonet connector receptacle 44. The transitional portion 52 can be formed so as to extend, for example, in an arc shape or in a substantially rectilinear manner in some region or regions in the circumferential direction around the tube axis R. In an alternative embodiment, the transitional portion 52 could also be positioned partially in the widening portion 38 of the muffler tube 30 or could be positioned fully in the widening portion 38, for example, in the region in which the widening portion 38 adjoins the second tube portion 36. For defined radial positioning of the muffler tube 30 in the tube passage opening 40, however, it is advantageous if the transitional portion 52 is at least partially, preferably fully, in the second tube portion 36.

Adjoining the transitional portion 52, at its end 54 remote from the insertion portion 46, is a locking portion 56 of the bayonet connector receptacle 44. The locking portion 56 can be configured so as to extend substantially parallel to the insertion portion 46 and, as FIG. 5 shows, extends in the same direction away from the transitional portion 52 in the direction of the tube axis R, and therefore the bayonet connector receptacle 44 fundamentally has a substantially U-shaped form.

The locking portion 56 has a locking end 58, which lies in the second tube portion 36 in the embodiment illustrated. The locking portion 56 could also extend partially into the widening portion 38 of the muffler tube 30, such that the locking end 58 is positioned in the widening portion 38 close to the transition to the second tube portion 36, for example. Moreover, the locking portion 56 could also be provided simply by a circular radial bulge adjoining the transitional portion 52, or be formed by an end portion of an arc-shaped transitional portion 52.

At least one bayonet connector projection 60 is formed on the muffler wall 18 in the region of the tube passage opening 40, projecting radially inward into the tube passage opening 40. A bayonet connector projection of this kind is preferably provided on the muffler wall 18 in association with each bayonet connector receptacle 44 on the muffler tube 30. As FIGS. 3 and 4 clearly show, a bayonet connector projection 60 of this kind can be provided, for example, by a radially inward-oriented formation on the opening rim 42. In this case, the circumferential extent of a bayonet connector projection 60 of this kind is chosen in such a way that it is at least slightly smaller than the width of the insertion portion 46 or of the locking portion 56 in the circumferential direction around the tube axis R, while the extent thereof in the direction of the tube axis R is at least slightly smaller than the axial width of the transitional portion 52. This ensures that a locking portion 60 of this kind can be moved through the insertion portion 46 and the transitional portion 52 into the locking portion 56 to establish the locked state.

To establish the locked state, the muffler tube 30 is moved with its first tube portion 34 in the lead toward the muffler wall 18 or inserted into the tube passage opening 40 in such a way that the bayonet connector projections 60 provided on the muffler wall 18 are in each case aligned in the circumferential direction with the insertion portion 46 of one of the bayonet connector receptacles 44. During this process, the muffler tube 30 is moved toward the muffler wall 18 in a direction of movement B that can be seen in FIG. 2. In the course of this movement, the bayonet connector projections 60 provided on the muffler wall 18 enter the insertion portions 46 of the bayonet connector receptacles 44, the insertion portions extending in the widening portion 38 of the muffler tube 30 and, as a result, being open toward the first tube portion 34 in the axial direction. The movement in direction of movement B can be continued until, as illustrated by a movement arrow P, a respective bayonet connector projection 60 gets into the region of the transition from the insertion portion 46 receiving it to the adjoining transitional portion 52.

When this positioning is achieved, the muffler tube 30 is rotated into the tube axis R with respect to the muffler wall 18, such that a respective bayonet connector projection 60 moves along the transitional portion 52 into the region of the locking portion 56. Then or already in the course of this rotary movement, the movement in direction of movement B is continued, such that a respective bayonet connector projection 60 moves into the position (depicted in dashed lines in FIG. 5) at the locking end 58 of the associated bayonet connector receptacle 44. In this state, further axial movement and circumferential movement of the muffler tube 30 is no longer possible and the tube is thus positioned in a defined way with respect to the muffler wall 18 in a locking position of the bayonet connector 32.

Since the locking portion 56 is of axially shorter configuration than the insertion portion 46, and the locking end 58 is positioned either in the second tube portion 36 or in the widening portion 38 close to the second tube portion 36, the muffler tube 30 is positioned in such a way with respect to the muffler wall 18 in the locking position that the opening rim 42 axially overlaps the second tube portion 36, at least in a certain region. Since the inside dimension of the tube passage openings in the region of the opening rim 40 is matched to the outside dimension of the second tube portion 36 of the exhaust tube 30, that is, is only slightly larger than the outside dimension, the bayonet connector 32 not only positions the exhaust tube 30 in a defined manner with respect to the muffler wall 18 in the axial direction and in the circumferential direction but, by virtue of the interaction between the second tube portion 30 and the opening rim 42, also positions it in a defined manner in the radial direction.

To ensure that the muffler tube 30 or bayonet connector 32 remains in the locking position when subject to the vibrations that occur in a vehicle, further measures that produce a firm connection between the muffler tube 30 and the muffler wall 18 can be taken. Thus, for example, when the locking position is reached during the assembly of the muffler, one or more welds, for example, in the form of spot welds, can be produced in the region in which the muffler wall 18 adjoins the muffler tube 30. Alternatively or in addition, the muffler tube 30 can be radially expanded, at least in its longitudinal portion passing through the tube passage opening 40, ensuring that the tube is pressed radially outward against the muffler wall 18 or opening rim 42. During this expansion process, a slight radial expansion of the opening rim can also be produced.

Via the above-described connection of the muffler tube 30 to the muffler wall 18 via the bayonet connector 32, such stable positioning of the muffler tube 30 is achieved that further support measures are not required. Depending on the embodiment of the muffler 10, however, provision can also be made for the first tube portion 34 and/or the second tube portion 36 of the muffler tube 30, for example, to pass through a further muffler wall, acting as a partition wall, in the muffler interior 14 and to be supported thereon at least radially. If the muffler tube 30 is embodied with multiple radial steps, the tube could also be connected to two or more correspondingly dimensioned muffler walls via respective bayonet connectors 32 of this kind.

The muffler tube 26 acting as an inlet tube and/or the muffler tube 28 acting as an outlet tube could, for example, also be connected to the muffler wall 18 acting as a partition wall via a bayonet connector of this kind and pass via a respective cylindrical portion through a tube passage opening in the associated muffler wall 16 or 20 and be welded thereto to obtain a gastight closure. In this case, it is possible to dispense with a weld in the region of the bayonet connector or the radial expansion. There is furthermore the possibility of positioning a muffler tube acting as an inlet tube or outlet tube substantially transversely to the muffler axis S so as to extend through the circumferential wall 12. A muffler wall acting as a supporting wall, in which a muffler tube of this kind is positioned so as to engage therein, can be arranged in the muffler interior 14 so as to extend substantially in the direction of the muffler axis S. The connection between a muffler tube of this kind and a muffler wall of this kind acting as a supporting wall can be effected via a bayonet connector 32 in the manner described above.

In embodiments in which gas leaks, for example, between the two chambers 22, 24, are fundamentally unproblematic or permissible and there are possibly further openings provided in the muffler wall 18 which allow gas to pass through, the bayonet connector receptacles 44 can be configured as slot-type receiving openings that pass through the muffler tube 30 or a tube wall thereof, as can be seen especially in FIGS. 2, 3 and 4. If the passage of gas should be prevented as far as possible in the region of the bayonet connector 32, the bayonet connector receptacles 44 can be configured as radially inward-directed receiving recesses or formations, similarly to the case with bayonet connector projections 60.

Although at least the insertion portion 46, and preferably also the locking portion 56, extend in the direction of the tube axis R to enable the process for the production of the locked state in the bayonet connector receptacles 44 to be carried out easily, these portions may be angled relative to the tube axis R, running in a V shape with respect to one another for example, such that the insertion of a respective bayonet projection 60 into an associated insertion portion 46 or locking portion 56 can include the movement in direction of movement B accompanied by a rotation about the tube axis R.

In another alternative embodiment, the bayonet connector formations 44 can be provided, for example, on the muffler wall 18 in the region of the tube passage opening 40 or opening rim 42, and bayonet connector projections 60 can be formed as radially-outward oriented formations, for example, on the muffler tube 30. The embodiment of the muffler tube 30 with regions of different outside dimensions is not required here. The bayonet connector formations 44 can be arranged on the muffler wall 18 in such a way that the insertion end 48 of the respective insertion portion 46 is positioned in the rounded transitional region from the opening rim 42 to a plate-type body region of the muffler wall 18 and is thus axially open in the direction of the tube axis R to receive a respective bayonet connector projection 60. The transitional portion 52 and the locking portion 56 can then be formed substantially in the opening rim 42.

If the muffler 10 is produced as a wound construction, it is possible to produce a muffler insert which includes all the muffler walls, that is, in the example illustrated, the muffler walls 16, 18, 20, and all or some of the muffler tubes, that is, in the embodiment illustrated, the muffler tubes 26, 28, 30. During the construction of this muffler insert, there is the possibility of connecting one or more of the muffler tubes in the manner described above to at least one of the muffler walls via a bayonet connector and, where required, to produce a material connection and/or force-locking engagement between a respective muffler tube and a muffler wall through which the tube passes. The circumferential wall 12 can be wound around the muffler insert produced in this way, or the insert can be inserted into a circumferential wall 12 already formed as a tubular component. The muffler walls 16, 20 of the embodiment illustrated, which act as end walls, can then be connected gas tightly to the circumferential wall 12 by forming, for example, beading, and/or by material joining, for example, welding.

When a muffler of this kind is used in an exhaust system of an internal combustion engine, the various components thereof, in particular the muffler tubes and the muffler walls, are advantageously configured as metal components, for example, metal parts generated by forming, into which the structures required to provide a respective bayonet connector can easily be machined. The principles of the present disclosure can also be applied, for example, in the case of a muffler used in an exhaust system of an internal combustion engine in which the various components are constructed from plastic, primarily for reasons of weight saving. The structures required to provide a bayonet connector can easily be provided in plastic components of this kind too.

It is understood that the foregoing description is that of the preferred embodiments of the invention and that various changes and modifications may be made thereto without departing from the spirit and scope of the invention as defined in the appended claims.