muffler

Abstract

The invention relates to a silencer for an exhaust system of an internal combustion engine, comprising a silencer housing having a circumferential wall extending elongated in the direction of a longitudinal axis (L) of the housing and at least one bottom wall (14) surrounded by or / and held on the circumferential wall and defining a chamber in the silencer housing, wherein at least one bottom wall opening (36) is provided in at least one bottom wall (14), the bottom wall opening surrounding an opening edge region (50) bent substantially in the direction of the longitudinal axis (L) of the housing on a substantially flat bottom wall region (48) of the bottom wall (14) and receiving an exhaust pipe (42) by means of a press fit.

Description

Technical Field

[0001] The invention relates to a muffler for an exhaust system of an internal combustion engine, for example in a motor vehicle. Background Art

[0002] For example, EP1888891B2 discloses a muffler comprising a muffler housing having a circumferential wall and a plurality of bottom walls, the bottom walls being surrounded by and supported on the circumferential wall. In the two axial end regions of the circumferential wall, the bottom walls form corresponding end walls that close the interior of the muffler housing outwardly in the direction of the longitudinal axis of the housing. In the region of the muffler housing between the two end walls, the bottom walls form corresponding intermediate walls that separate the chambers formed inside the muffler housing from each other. Such chambers can be connected to each other via openings provided in the corresponding intermediate walls, but can also form resonator chambers for Helmholtz resonators.

[0003] In order to allow an exhaust pipe, which also provides a resonator neck for such a Helmholtz resonance, to be guided through such a bottom wall, it is known to form an opening edge region by forming a flange, which surrounds the bottom wall opening and extends from a substantially flat area of the respective bottom wall toward the opening center axis of the respective bottom wall opening. This opening edge region has a substantially cylindrical structure and accommodates the exhaust pipe. The bottom wall opening surrounded by the respective opening edge region has an interference fit in its outer dimensions, i.e., for example, with respect to the outer diameter of an exhaust pipe having a substantially circular cross-section. This allows the exhaust pipe to be accommodated in such a bottom wall opening with minimal play and thus positioned in a suitable installation position. In this position, the respective exhaust pipe is then connected to the bottom wall through which it passes by a material connection, typically by welding, for a secure connection. Summary of the Invention

[0004] The object of the present invention is to provide a silencer for an exhaust system of an internal combustion engine and a method for producing such a silencer, by means of which a noise-free connection between a bottom wall and an exhaust pipe extending through the bottom wall can be achieved with a simplified design.

[0005] According to a first aspect of the invention, the task is solved by a muffler for an internal combustion engine exhaust device, which comprises a muffler housing having a circumferential wall extending elongated in the direction of the longitudinal axis of the housing and at least one bottom wall surrounded by or / and retained on the circumferential wall, defining a chamber in the muffler housing, wherein at least one bottom wall opening is provided in at least one bottom wall, which bottom wall opening surrounds an opening edge area that is bent essentially in the direction of the longitudinal axis of the housing on a substantially flat bottom wall area of the bottom wall and receives the exhaust pipe by means of a press fit.

[0006] In the muffler according to the invention, at least one exhaust pipe is held in the associated bottom wall opening by means of a press fit. This, on the one hand, provides a stable connection, and on the other hand, due to the constant contacting contact under pressure or preload, prevents relative movements between the bottom wall and the exhaust pipe extending therethrough, which could lead to stop noises or rattling. In principle, no further measures are required to provide a secure connection, although, in addition to the press fit, a material connection, such as a welded connection, can also be provided.

[0007] In particular, if a gas-tight seal is to be achieved in the region of the connection of the bottom wall to the exhaust pipe, for example to provide a Helmholtz resonator, it is advantageous if the opening edge region is designed completely around the opening center axis of the bottom wall opening in the circumferential direction.

[0008] In an alternative embodiment, the opening edge region can be configured to be interrupted in the circumferential direction around the opening center axis of the bottom wall opening. This can be achieved, for example, by having the opening edge region comprise a plurality of opening edge region segments that are spaced apart from one another in the circumferential direction around the opening center axis of the bottom wall opening.

[0009] In a cost-effective design that is still resistant to the high temperatures and corrosive components of the internal combustion engine's exhaust gas, the at least one bottom wall can be designed as a formed sheet metal part. In particular, if the opening edge region is to be closed in the circumferential direction, for example to also achieve a substantially gas-tight seal, it is advantageous for the at least one bottom wall to have a wall thickness of a maximum of 1 mm, preferably a maximum of 0.6 mm. In this case, the bottom wall can also be sufficiently deformed in its elastically deformable region in the region of the closed opening edge region to produce a press fit when the exhaust pipe is pushed or pressed into the bottom wall opening, so that the exhaust pipe can be received and a sufficiently strong pressing force can be applied to its outer circumferential surface.

[0010] The opening edge region can include a first edge section connected to the substantially flat bottom wall region in a first curved region and a second edge section connected to the first edge section in a second curved region, wherein the radial distance of the first edge section from the opening center axis of the bottom wall opening preferably decreases substantially constantly in the direction from the first curved region to the second curved region. The region of the minimum distance of the opening edge region from the opening center axis can then be provided in the region of the second curved region.

[0011] The radial distance of the second edge section from the central axis of the opening can be substantially constant in the direction facing away from the second curvature region, thereby forming a substantially cylindrical region in which a planar contact is formed between the edge section of the opening and the exhaust pipe. For example, a materially bonded connection, such as a welded connection, can also be produced at the end face of this cylindrical section between the bottom wall and the exhaust pipe.

[0012] In a design which in particular assists in slightly pressing the exhaust pipe into the bottom wall opening which receives it and avoids tilting of the exhaust pipe when it is pushed into the bottom wall opening, the radial distance of the second edge section relative to the center axis of the opening preferably increases substantially constantly in a direction away from the second bending area.

[0013] Furthermore, it can be provided that the opening edge region extends in a curved manner from a first axial end region of the opening edge region adjoining the essentially flat region of the bottom wall toward an axial region of the opening edge region having the smallest distance from the opening center axis of the bottom wall opening.

[0014] Here, if the opening edge area further extends in a curved manner from an area of the opening edge area having a minimum distance from the opening center axis of the bottom wall opening toward a second axial end area of the opening edge area which is a basically flat area away from the bottom wall, the entire opening edge area can be provided as a deformation area of the bottom wall, for example, which is constructed with an approximately constant radius of curvature in the axial direction.

[0015] The at least one bottom wall may be an intermediate wall separating the two chambers in the muffler housing from each other. Alternatively, the at least one bottom wall may be an end wall arranged at the axial end region of the circumferential wall. It should be noted that, of course, one or more intermediate walls and one or both end walls in the muffler may be implemented as a bottom wall having the above-described structure. Furthermore, it should be noted that a plurality of bottom wall openings may also be constructed in one or more of these bottom wall openings, and one, or if necessary, a plurality or all of these bottom wall openings may have the above-described structure for receiving the corresponding exhaust pipe using a press fit.

[0016] According to a further aspect, the object given at the outset is achieved by a method for producing a silencer for an exhaust system of an internal combustion engine, in particular a silencer designed according to the invention, comprising the following measures:

[0017] a) providing the muffler housing with at least one bottom wall, such that at least one bottom wall opening formed in the bottom wall is surrounded by an opening edge region which is curved from a substantially flat bottom wall region substantially in the direction of the opening center axis, such that the bottom wall opening has a predetermined inner dimension, preferably an inner diameter,

[0018] b) providing an exhaust pipe with predetermined outer dimensions, preferably an outer diameter, which is received in the bottom wall opening surrounded by the opening edge region, wherein the predetermined outer dimensions of the exhaust pipe are greater than the predetermined inner dimensions of the bottom wall opening,

[0019] c) inserting the exhaust pipe into the bottom wall opening surrounded by the opening edge region so as to hold the exhaust pipe in the bottom wall opening surrounded by the opening edge region by press-fitting.

[0020] It should be noted that in the areas of interaction during the construction of the muffler, dimensions that are specifically coordinated with one another are taken into account. This means that the exhaust pipe has an interference fit relative to the bottom wall opening formed for receiving the exhaust pipe in the bottom wall in the area where it penetrates the bottom wall during the construction of the muffler, but can, for example, have smaller cross-sectional dimensions than the bottom wall opening in other length areas, or even larger cross-sectional dimensions if necessary.

[0021] It should also be pointed out that, preferably when constructing a silencer according to the invention or when implementing a method according to the invention, such a bottom wall opening and the exhaust pipe received therein are preferably each constructed with a circular cross-section, so that the internal dimensions can be represented, for example, by an inner diameter and the external dimensions can be represented, for example, by an outer diameter.

[0022] In measure a), the opening edge region can be provided completely around the central axis of the opening in the circumferential direction. Alternatively, it can be provided that in measure a), the opening edge region is provided interrupted in at least one peripheral region. For example, the opening edge region can be configured with a plurality of opening edge region segments that are spaced apart from one another in the circumferential direction around the central axis of the opening.

[0023] In measure a), starting from a substantially flat region of the bottom wall, an opening edge region can be provided which has a decreasing distance from the opening center axis toward an axial region of the opening edge region having the smallest distance from the opening center axis.

[0024] Furthermore, in measure a), an opening edge region may be provided, which has a substantially constant spacing relative to the opening center axis from a region of the opening edge region having the smallest spacing from the opening center axis to a free axial end region of the opening edge region. Alternatively, in measure a), an opening edge region may be provided, which has an increasing spacing relative to the opening center axis from a region of the opening edge region having the smallest spacing from the opening center axis to a free axial end region of the opening edge region.

[0025] In order to enable the exhaust pipe to be inserted into the bottom wall opening and to achieve a sufficiently secure press fit, it is recommended that the difference between the predetermined outer dimensions of the exhaust pipe and the predetermined inner dimensions of the bottom wall opening provided for receiving the exhaust pipe be in the range of 0.2 mm to 0.6 mm, preferably approximately 0.4 mm. To this end, it can further be provided that, in measure a), the at least one bottom wall is provided as a formed sheet metal part and / or has a wall thickness of at most 1 mm, preferably at most 0.6 mm.

[0026] Furthermore, in order to achieve a stable connection, provision can be made for measure d) to connect the exhaust pipe to the edge region of the opening by material bonding, preferably welding. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The present invention will be described in detail below with the help of the accompanying drawings.

[0028] Figure 1 A partial axial view of the bottom wall for the muffler is shown in the region of the bottom wall opening;

[0029] Figure 2 Show Figure 1 a partial axial cross-sectional view of the bottom wall;

[0030] Figure 3 Show Figure 1 and 2 a partial view of the bottom wall in the region of the bottom wall opening through which the exhaust pipe passes;

[0031] Figure 4 Showing the basis for an alternative design Figure 3 Schematic diagram of the principle;

[0032] Figure 5 Another basis for explaining the size ratio is shown. Figure 3 Schematic diagram of the principle;

[0033] Figure 6 Another basis showing an alternative design solution Figure 3 Schematic diagram of

[0034] Figure 7 A principle longitudinal section of a muffler comprising a plurality of bottom walls is shown. DETAILED DESCRIPTION

[0035] In reference Figures 1 to 6 Before explaining below various configurations or configuration details of the bottom wall of a muffler for an exhaust system of an internal combustion engine, for example in a vehicle, reference is first made to Figure 7The following describes an example of the basic structure of a silencer 10, which in the example shown comprises a total of four bottom walls 12, 14, 16, 18. The silencer housing 20 of the silencer 10 further comprises a circumferential wall 22 extending elongated in the direction of the housing longitudinal axis L, for example, substantially cylindrical, which connects to the radially outer regions of the bottom walls 12, 14, 16, 18 or surrounds them.

[0036] The bottom walls 12, 18, which are arranged at the axial end regions 24, 26 of the circumferential wall 22, form the respective end walls of the muffler housing 20, which close the muffler interior at both axial ends. The bottom walls 12, 18 can be fixedly and gas-tightly connected to the circumferential wall 22 in their radially outer regions by a material connection, such as welding. Alternatively or additionally, the bottom walls 12, 18, which provide the respective end walls, can be fixedly and gas-tightly connected to the circumferential wall 22 in the axial end regions 24, 26 by a form fit, such as by crimping.

[0037] The bottom walls 14, 16 arranged between the bottom walls 12, 18 providing the two end walls form respective intermediate walls which, in conjunction with each other or with the bottom walls 12, 18 providing the end walls, divide the interior of the muffler into a total of three chambers 28, 30, 32. The bottom walls 14, 16 providing the intermediate walls can be held in a defined position, for example, on the inner periphery of the circumferential wall 22 by clamping and / or material bonding, for example welding.

[0038] In the illustrated embodiment, the bottom walls 12, 14, 16, and 18 each have a bottom wall opening 34, 36, 38, and 40 in the central region, the structure of which will be described in greater detail below. An exhaust pipe 42 penetrates the bottom wall openings 34 and 36 of the bottom walls 12 and 14, which can, for example, form an inlet pipe through which the exhaust gas is introduced into the muffler interior. An exhaust pipe 44 penetrates the bottom wall openings 38 and 40 of the bottom walls 16 and 18, which can, for example, provide an outlet pipe through which the exhaust gas is discharged from the muffler 10.

[0039] The exhaust pipe 42 can, for example, open into the chamber 28 formed between the two bottom walls 12, 14 and can, in its axial end region, open into the chamber formed between the two bottom walls 14, 16. The chamber 28 can be connected to the chamber 30 via one or more throughflow openings formed in the bottom wall 14. The chamber 32 can form the resonator chamber of a Helmholtz resonator and be connected to the chamber 30 via an exhaust pipe 46 arranged in the bottom wall 16 and forming the resonator neck.

[0040] It should be noted that the aforementioned reference Figure 7The described muffler structure is merely exemplary and can vary in various ways. This can include the number and positioning of the bottom walls provided on the muffler, as well as the number of exhaust pipes that introduce exhaust gas into the muffler or the number of exhaust pipes that discharge exhaust gas from the muffler. The exhaust gas routing within the muffler can also differ from the illustrated example.

[0041] Next refer to Figures 1 to 6 The design of the bottom wall provided in muffler 10 in the area of the bottom wall opening through which the exhaust pipe passes will be described in detail. It should be noted that this design, as will be described below, can be implemented in each of the bottom walls provided in muffler 10, namely, in the illustrated example, in each of bottom walls 12, 14, 16, and 18, where the corresponding exhaust pipe 42 or 44 passes through them. This structure can also be provided in conjunction with exhaust pipe 46, which provides a resonator neck, as will be described below. Of course, differently configured bottom wall openings can also be provided in the bottom wall to guide the exhaust pipe through them, and not all bottom wall openings provided in one or more bottom walls necessarily have the structure described below.

[0042] The structure of such a bottom wall is described below by way of example with reference to the bottom wall 14 , which forms an intermediate wall and separates the muffler interior from one another by two chambers 28 , 30 which are in exhaust gas exchange connection with one another.

[0043] Figures 1 to 3 The region of the bottom wall 14 is shown in which the exhaust pipe 42 penetrates the bottom wall opening 36 provided therein. In this region, a bead, for example, formed as an opening edge region 50, extending from a substantially flat bottom wall region 48 of the bottom wall 14 oriented substantially orthogonally to the housing longitudinal axis L, is bent in the direction of the housing longitudinal axis L, which corresponds to the opening center axis M in the illustrated embodiment. To this end, the bottom wall 14, which is formed of sheet metal material in the region of the bottom wall opening 36, is formed by a corresponding die. It should be noted that an edge region bent in the direction of the housing longitudinal axis L can also be formed in the radially outer region, i.e., in the position where the bottom wall 14 is held against the circumferential wall 22.

[0044] In an embodiment of the bottom wall 14 that separates two chambers 28, 30 that are in exhaust exchange connection with each other, the opening edge area 50 can be interrupted in the circumferential direction and, for example, constructed with four opening edge area segments 52 that follow each other in the circumferential direction and are arranged at circumferential intervals from each other, and corresponding circumferential gaps 54 are formed between the opening edge area segments in the bottom wall 14 or in the essentially flat bottom wall area 48, through which the two chambers 28, 30 separated from each other by the bottom wall 14 can be in exhaust exchange connection with each other.

[0045] If an airtight closure is to be provided by such a bottom wall, as is the case, for example, in combination with a bottom wall 12, 18 providing an end wall or a bottom wall 16 providing an intermediate wall, the opening edge area 50 can be constructed as an opening edge area which completely surrounds the respective opening center axis M of the respective bottom wall opening 34, 40 or 38 in the circumferential direction and is uninterrupted in the circumferential direction.

[0046] exist Figures 1 to 3 In the exemplary embodiment of the embodiment, the opening edge region 50 has a first edge section 58 that connects to the essentially flat bottom wall region 48 in a first curvature region 56. The first edge section 58 has a structure that tapers in an essentially conical or truncated-conical manner with respect to the opening center axis M starting from the first curvature region 56, so that the distance between the first edge section 58 and the opening center axis M decreases essentially constantly starting from the first curvature region 56. This means that, viewed in the axial direction, the first edge section 58 is essentially uncurved, but rather has a structure that is, for example, circularly curved about the opening center axis M. In a second curvature region 60, a second edge section 62 connects to the first edge section 58. The second edge section 62 also has a conical or truncated-conical structure, so that its radial distance from the opening center axis M increases essentially constantly starting from the second curvature region 60. Therefore, the opening edge area 50 has a basically V-shaped structure in the longitudinal section between the first axial end area 64 and the second axial end area 66, the first axial end area is connected to the basically flat bottom wall area 48 in the area of the first bending area 56, and the second axial end area is arranged away from the bottom wall area 48.

[0047] At the location where the two edge sections 58, 62 are connected to one another, ie substantially in the region of the second curved region 60, the opening edge region 50 has a minimum distance from the opening center axis M of the bottom wall opening 36. Figure 5In the state shown, in which the exhaust pipe 42 has not yet penetrated the bottom wall 14 or the bottom wall opening 36 constructed in the bottom wall, the minimum distance corresponds to a predetermined internal dimension a, which, in particular in the case of a substantially circular design of the bottom wall opening 36, can represent the radius of the bottom wall opening 36 relative to the opening center axis M or the inner diameter (i.e., twice the radius).

[0048] The exhaust pipe 42 is dimensioned such that its predetermined external dimension A (e.g., also represented by a radius or double radius, i.e., the diameter of the exhaust pipe 42, which is designed, for example, with a circular cross section) is greater than a corresponding predetermined internal dimension a of the bottom wall opening 36. For example, the external dimension A, i.e., the diameter of the exhaust pipe 42 corresponding to the double radius R, can be configured with an excess in the range of 0.20 mm to 0.6 mm, preferably approximately 0.4 mm, relative to the corresponding internal dimension a, i.e., the inner diameter of the bottom wall opening 36.

[0049] During assembly of the muffler 10, after the bottom wall 14 has been provided with the desired shaping and, if necessary, surrounded by the circumferential wall 22, the exhaust pipe 42 is inserted into the bottom wall opening 36 in the direction of the opening center axis M or the housing longitudinal axis L of the muffler 10. Due to the interference fit of the exhaust pipe 42 relative to the bottom wall opening 36 receiving it, the opening edge region 50 expands slightly radially during insertion of the exhaust pipe 42, so that the exhaust pipe 42 is retained in the bottom wall opening 36 by a press fit and, therefore, a force-locking fit. The radially expanded opening edge region 50, or its opening edge region section 52, in its elastically deformable region, is pressed radially inwardly against the outer periphery of the exhaust pipe 42 with a force F. This, on the one hand, maintains the exhaust pipe 42 in a defined position relative to the bottom wall 14, and, on the other hand, the opening edge region section 52, pressed against the outer periphery of the exhaust pipe 42 with the force F, creates a defined contact with the exhaust pipe 42, thereby preventing rattling.

[0050] Due to the design of the opening edge area 50 with its two edge sections 58, 62 which essentially provide a V-shaped profile of the opening edge area 50, an introduction bevel is formed for the exhaust pipe 42 to be received in the bottom wall opening 36, which enables the exhaust pipe 42 to be easily inserted into the bottom wall opening 36 and avoids getting caught due to abutting contact with sharp edges.

[0051] Even when the opening edge region 50 is designed to be uninterrupted in the circumferential direction, that is, as a circumferentially continuous opening edge region, it can still expand radially when the exhaust pipe 42 is inserted into the bottom wall opening 36. In the case of a circumferentially closed design of the opening edge region 50, it is advantageous to provide the bottom wall 14 with a relatively small wall thickness W of a maximum of 1 mm, preferably a maximum of 0.6 mm. This thin-walled design of the bottom wall 14 ensures that when the exhaust pipe 42 is inserted into the bottom wall opening 36, the circumferentially closed opening edge region 50 expands accordingly due to the small interference fit of the exhaust pipe 42 and, due to its elasticity, applies a force F, which then acts radially inwardly and substantially uniformly over the entire circumference, to the exhaust pipe 42.

[0052] exist Figure 4 An alternative design of the bottom wall 14 is shown in FIG. In this design, the opening edge region 50 is also formed with two edge sections 58, 62. The edge section 58 adjoins the essentially flat bottom wall region 48 in an axial end region 64 of the opening edge region 50, while the edge section 62 provides a second axial end region 66 facing away from the bottom wall region 48. The two edge sections 58, 62 are formed to be curved in the axial direction and have, for example, a greater curvature than in FIG. Figure 3 The two curved regions 56, 60 of the embodiment shown in FIG. have significantly greater radii of curvature. For example, a substantially constant radius of curvature can be provided in each of the edge sections 58, 62 up to the region 68 of the smallest diameter of the open edge region 50, and the radii of curvature in the two edge sections 58, 62 can be, for example, equal to one another, but can of course also be designed differently. For example, the radius of curvature in the edge section 62 can be smaller than the radius of curvature in the edge section 58.

[0053] exist Figure 4 In the design approach shown, the opening edge area 50 can also be closed in the circumferential direction, for example as is required in the area of the bottom walls 12, 40 providing the corresponding end walls in order to obtain an airtight closure, but alternatively the previously described design approach of segmentation in the circumferential direction can also be provided in order, on the one hand, to provide increased flexibility in the area of the bottom wall opening and, on the other hand, to enable gas to pass through the bottom wall opening in this area.

[0054] exist Figure 6 Another alternative design is shown in FIG. In this design, the opening edge region 50 does not have two edge sections 58, 62, which are connected to the essentially flat bottom wall region 48 or to each other in the respective curved regions 56, 60. The edge section 58, for example, also has Figure 3, wherein the distance between the two bend regions 56, 60 and the opening center axis M decreases substantially constantly. The second edge section 62 has a substantially cylindrical design, i.e., a substantially constant distance from the opening center axis M between the second bend region 60 and the second axial end region 66, so that a minimum distance from the opening center axis M is provided between the second bend region 60 and the second axial end region 66. Thus, in this embodiment, a substantially planar contact area, thus further expanded in the axial direction, is provided between the opening edge region 50 and the exhaust pipe 42. This is suitable for providing, in addition to the press fit generated by the radially inwardly applied force F, a secure connection between the bottom wall 14 and the exhaust pipe 42 by material bonding, for example, by a circumferentially circumferentially extending weld seam 70, which can be configured as a fillet weld between the substantially axially oriented end face of the second edge section 62 and the outer circumferential surface of the exhaust pipe 42.

[0055] exist Figure 6 In the design scheme shown, the opening edge area 50 can also be constructed in a circumferential direction in a circumferential manner, i.e. uninterrupted, or can be provided as an opening edge area that is interrupted at at least one position in the circumferential direction, for example as an opening edge area having multiple opening edge area segments following each other in the circumferential direction.

[0056] Finally, it should be pointed out that the Figures 1 to 6 The described structure of the bottom wall opening or the opening edge region surrounding the bottom wall opening can be provided on each bottom wall through which the exhaust pipe penetrates. Of course, bottom wall openings provided on different bottom walls or opening edge regions having different structures can also be provided. This can be selected, for example, based on the diameter of the exhaust pipe penetrating the corresponding bottom wall, or based on whether an airtight seal is to be achieved in the region of the bottom wall opening through which the exhaust pipe penetrates, or whether exhaust gas is to be allowed to pass through.

[0057] In each of the above-described designs of the bottom wall, it is possible to simply insert the exhaust pipe manually or mechanically through the corresponding bottom wall or into the bottom wall opening provided for receiving the exhaust pipe, wherein the corresponding opening edge region is expanded and forms the force-locking connection required to produce the press fit. During operation of a muffler designed in this manner, the various components of the muffler heat up and expand, thereby increasing the press fit or the force exerted on the associated exhaust pipe by the corresponding opening edge region and thus producing an even stronger retaining effect.

Claims

1. A muffler for an exhaust system of an internal combustion engine, comprising a muffler housing (20) having a circumferential wall (22) extending elongated in the direction of a longitudinal axis (L) of the housing and at least one bottom wall (12, 14, 16, 18) surrounded by or / and held on the circumferential wall (22) and defining a chamber (28, 30, 32) in the muffler housing (20), wherein: At least one bottom wall opening (34, 36, 38, 40) is provided in at least one bottom wall (12, 14, 16, 18), the bottom wall opening being surrounded by an opening edge region (50) bent in the direction of the housing longitudinal axis (L) on a flat bottom wall region (48) of the bottom wall (12, 14, 16, 18) and receiving an exhaust pipe (42, 44) by means of a press fit, the opening edge region (50) being constructed interruptedly around an opening center axis (M) of the bottom wall opening (34, 36, 38, 40) in a circumferential direction and comprising a plurality of opening edge region sections (52) spaced apart from one another in a circumferential direction around the opening center axis (M) of the bottom wall opening (34, 36, 38, 40), the opening edge region (50) having a first bending region (56) connected to the flat bottom wall region (48) and extending to the opening edge. A first edge section (58) of an edge region (50) having an axial region (68) with a minimum distance from an opening center axis (M), wherein the radial distance of the first edge section (58) from the opening center axis (M) of the bottom wall opening (34, 36, 38, 40) decreases in a direction from the first bending region (56) to the axial region (68) of the opening edge region (50) with a minimum distance from the opening center axis (M), characterized in that the opening edge region (50) has a second edge section (62) connected to the first edge section (58) in the second bending region (60) in the region of the axial region (68) of the opening edge region (50) with a minimum distance from the opening center axis (M), and the radial distance of the second edge section (62) to the opening center axis (M) increases in a direction away from the second bending region (60).

2. The muffler according to claim 1, characterized in that The at least one bottom wall (12, 14, 16, 18) is designed as a formed sheet metal part and / or the at least one bottom wall (12, 14, 16, 18) has a wall thickness (W) of at most 1 mm.

3. The muffler according to claim 1 or 2, characterized in that: The radial distance of the first edge sections (58) decreases constantly.

4. The muffler according to claim 1 or 2, characterized in that: The radial distance of the second edge section (62) increases constantly.

5. The muffler according to claim 1 or 2, characterized in that: The opening edge region (50) extends in a curved manner from a first axial end region (64) of the opening edge region (50) connected to the flat bottom wall region (48) toward an axial region (68) of the opening edge region (50) having a minimum distance from an opening center axis (M) of the bottom wall opening (34, 36, 38, 40).

6. The muffler according to claim 5, characterized in that The opening edge region (50) extends in a curved manner from a region (68) of the opening edge region (50) having a minimum distance from an opening center axis (M) of the bottom wall opening (34, 36, 38, 40) toward a second axial end region (66) of the opening edge region (50) remote from the flat bottom wall region (48).

7. The muffler according to claim 1 or 2, characterized in that: The at least one bottom wall (14, 16) is an intermediate wall which separates two chambers (28, 30, 32) in the muffler housing (20) from one another, or the at least one bottom wall (12, 18) is an end wall which is arranged at an axial end region (24, 26) of the circumferential wall (22).

8. The muffler according to claim 1 or 2, characterized in that: Opening edge area sections (52) spaced apart from one another in the circumferential direction around the opening center axis (M) of the bottom wall opening (34, 36, 38, 40) are bent in the same axial direction.

9. Method for producing a muffler (10) for an exhaust system of an internal combustion engine, the muffler (10) being a muffler according to any one of the preceding claims, the method comprising the following measures: a) providing a muffler housing (20) with at least one bottom wall (12, 14, 16, 18), such that at least one bottom wall opening (34, 36, 38, 40) formed in the bottom wall (12, 14, 16, 18) is surrounded by an opening edge region (50) that is bent from a flat bottom wall region (48) in the direction of an opening center axis (M), such that the bottom wall opening (34, 36, 38, 40) has a predetermined inner dimension (a) in an axial region (68) of the opening edge region (50) that has a minimum distance from the opening center axis (M), b) providing an exhaust pipe (42, 44) having predetermined outer dimensions (A) to be received in a bottom wall opening (50) surrounded by an opening edge region (50), wherein The predetermined outer dimension (A) of the exhaust pipe (42, 44) is greater than the predetermined inner dimension (a) of the bottom wall opening (34, 36, 38, 40), c) inserting the exhaust pipe (42, 44) into the bottom wall opening (34, 36, 38, 40) surrounded by the opening edge area (50) so that the exhaust pipe (42, 44) is retained in the bottom wall opening (34, 36, 38, 40) surrounded by the opening edge area (50) by press fitting.

10. The method according to claim 9, characterized in that In measure a), an opening edge region (50) is provided interrupted in at least one circumferential region, said opening edge region having a plurality of opening edge region sections (52) arranged at a distance from one another in the circumferential direction around the opening center axis (M).

11. The method according to claim 9 or 10, characterized in that In measure a), an opening edge region (50) is provided starting from a flat bottom wall region (48), which has a decreasing distance from the opening center axis (M) up to an axial region (68) of the opening edge region (50) having the smallest distance from the opening center axis (M).

12. The method according to claim 11, characterized in that In measure a), an opening edge region (50) is provided which has an increasing distance from the opening center axis (M) from a region (68) of the opening edge region (50) having the smallest distance from the opening center axis (M) to a free axial end region of the opening edge region (50).

13. The method according to claim 10 or 11, characterized in that The difference between a predetermined outer dimension (A) of the exhaust pipe (42, 44) and a predetermined inner dimension (a) of a bottom wall opening (34, 36, 38, 40) provided for receiving the exhaust pipe (42, 44) is in the range of 0.2 mm to 0.6 mm, or / and, in measure a), the at least one bottom wall (12, 14, 16, 18) is provided as a sheet metal formed part and / or has a wall thickness (W) of a maximum of 1 mm.

14. The method according to claim 13, characterized in that The difference between a predetermined outer dimension (A) of the exhaust pipe (42, 44) and a predetermined inner dimension (a) of a bottom wall opening (34, 36, 38, 40) provided for receiving the exhaust pipe (42, 44) is 0.4 mm, or / and in measure a) the at least one bottom wall (12, 14, 16, 18) is provided with a wall thickness (W) of a maximum of 0.6 mm.

15. The method according to claim 10 or 11, characterized in that Measure d) is provided for connecting the exhaust pipe (42, 44) to the opening edge region (50) by a material bond.

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