Silencer for an exhaust system and method for producing a silencer

Abstract

A silencer for an exhaust system comprises a circumferential wall (12) defining a silencer interior (14), at least one silencer wall (18, 20) adjoining the circumferential wall (12) and / or arranged in the silencer interior, at least one silencer tube extending in the direction of a pipe axis (R) and passing through a pipe opening (40) in at least one silencer wall (16, 18, 20), wherein at least one silencer tube (30) passing through a pipe opening (40) in a silencer wall (18) is connected to the silencer wall (18) by means of a bayonet fitting (32).

Description

Description

[0001] The present invention relates to a silencer for an exhaust system, for example for an internal combustion engine. The present invention further relates to a method for manufacturing such a silencer.

[0002] In the manufacture of components such as rear silencers in the exhaust systems of internal combustion engines used as drive units in motor vehicles, silencer tubes guided through the silencer walls inside the silencer are generally connected to the silencer walls by creating a weld after inserting and precisely positioning the silencer tubes into the receiving pipe openings. It is also known to radially expand such silencer tubes in front of and behind the silencer wall after insertion into their respective pipe openings, thus creating a positive fit between the silencer tubes and the receiving silencer walls in the longitudinal direction of the silencer tubes.

[0003] The object of the present invention is to provide a silencer for an exhaust system and a method for manufacturing a silencer in which components are or are stably connected to one another in a simple manner.

[0004] According to the invention, this problem is solved by a silencer for an exhaust system, comprising: a circumferential wall enclosing a silencer interior, at least one silencer wall adjoining the circumferential wall and / or arranged in the silencer interior, at least one silencer pipe extending in the direction of a pipe axis and passing through a pipe opening in at least one silencer wall, wherein at least one silencer tube passing through a pipe opening in a silencer wall is connected to the silencer wall by means of a bayonet fitting.

[0005] A bayonet fitting of this type creates a stable, rattle-free connection between a silencer tube and a silencer wall, without necessarily requiring further joining measures, such as material-fit connections. At the same time, the bayonet fitting ensures a defined positioning of the connected components.

[0006] The bayonet fitting can comprise at least one bayonet fitting receptacle in one component of the silencer tube and silencer wall, preferably in the silencer tube, and a bayonet fitting projection on the other component of the silencer tube and silencer wall, preferably on the silencer wall, in association with at least one, preferably each, bayonet fitting receptacle.

[0007] To further improve the connection stability, the bayonet fitting can comprise a plurality of bayonet fitting receptacles arranged around the tube axis, preferably at uniform intervals.

[0008] For easy manufacture and locking of the connection, the bayonet fitting can comprise an insertion section extending substantially in the direction of the tube axis and open in the direction of the tube axis to receive a bayonet fitting projection, a transition section adjoining the insertion section and extending substantially circumferentially, and a locking section adjoining the transition section and extending substantially in the direction of the tube axis and closed in the direction of the tube axis.

[0009] In order to provide the structures required for a bayonet fitting in a silencer tube, the silencer tube can comprise a first tube section with a smaller outer dimension, a second tube section with a larger outer dimension, and an expansion section between the first tube section and the second tube section.

[0010] To accommodate a bayonet locking projection, the insertion section can extend in the expansion section in the direction from the first pipe section towards the second pipe section.

[0011] To utilize the axial length of the extension section for inserting a bayonet locking projection, an inserter end of the insertion section can be positioned within the extension section close to the first tube section. This means that the inserter end is positioned closer to the first tube section than to the second tube section, for example, immediately following the first tube section.

[0012] The transition section can be positioned in the extension section near the second pipe section and / or in the second pipe section. Near the second pipe section means that the transition section is positioned closer to the second pipe section than to the first pipe section, for example, following the second pipe section.

[0013] To create a positive fit between the silencer wall and the silencer pipe in the locked position, one locking end of the locking section can be positioned in the second pipe section or in the extension section near the second pipe section. "Near the second pipe section" again means that the locking end is positioned closer to the second pipe section than to the first pipe section.

[0014] For ease of manufacture, at least one bayonet fitting can comprise a receiving opening formed in, and thus passing through, a wall of the silencer tube. This design can be advantageously provided if the bayonet fitting is located entirely within the silencer's interior and gas leaks in the area of ​​the bayonet fitting are not problematic.

[0015] To avoid gas leaks in the area of ​​the bayonet fitting as much as possible, at least one bayonet fitting can include a recess formed in a pipe wall of the silencer tube.

[0016] The silencer wall can include an opening edge surrounding the pipe passage, bent in the direction of the pipe axis. The bayonet locking projection can include a radially inward-facing indentation at the opening edge.

[0017] In order to reliably prevent the at least one silencer tube, which is held to a silencer wall by means of a bayonet fitting, from detaching due to the vibrations occurring in a vehicle, it is proposed that the at least one silencer tube connected to a silencer wall by means of a bayonet fitting is further connected to the silencer wall by material connection, preferably one or more welds, and / or by force connection, preferably by radial expansion of the silencer tube in the section of the silencer tube passing through the pipe opening of the silencer wall.

[0018] The silencer wall, which is penetrated by a silencer tube and connected to it by means of a bayonet fitting, can be a partition separating two chambers in the interior of the silencer.

[0019] The present invention further relates to a method for manufacturing a silencer constructed according to the invention, comprising the following measures: a) Providing at least one component of the silencer tube and silencer wall, preferably the silencer tube, with at least one bayonet fitting, b) Providing the other component of the silencer tube and silencer wall, preferably the silencer wall, with at least one bayonet fitting projection, c) Inserting the at least one silencer tube into the tube opening of the at least one silencer wall such that each bayonet fitting projection on the other component of the silencer tube and silencer wall is received in a bayonet fitting receptacle of the one component of the silencer tube and silencer wall.

[0020] To prevent the bayonet fitting from being subsequently released, for example due to vibrations occurring in a vehicle, after measure c) has been brought into its locking position, it is proposed that measure d) be carried out to connect the at least one silencer pipe to the at least one silencer wall in a material-fit manner after measure c), and / or that measure e) be carried out to connect the at least one silencer pipe to the at least one silencer wall in a force-fit manner after measure c).

[0021] For example, measure d) may include the creation of at least one weld, i.e. the creation of one or more weld points.

[0022] Measure e) may include radially widening the at least one silencer tube in its axial area penetrating the tube opening of the at least one silencer wall.

[0023] The present invention is described in detail below with reference to the accompanying figures. These show: Fig. 1 a schematic longitudinal sectional view of a silencer; Fig. 2 a silencer wall penetrated by a silencer tube and connected to it by a bayonet fitting; Fig. 3 the area of ​​the bayonet fitting in Fig. 2 in a phase of manufacturing the connection between the silencer wall and the silencer pipe, Fig. 4 one of the Fig. 3 A corresponding representation in a later phase of the manufacture of the connection between the silencer wall and the silencer tube; Fig. 5 shows the area of ​​the bayonet fitting in principle.

[0024] The Fig. 1Figure 10 shows a simplified representation of a silencer 10, used, for example, as a rear silencer in the exhaust system of an internal combustion engine in a vehicle. The silencer 10 comprises a circumferential wall 12, which is elongated in the direction of a silencer axis S in a tube-like, for example cylindrical, manner and which radially defines the inner space 14 of the silencer. The silencer 10 further comprises a plurality of silencer walls 16, 18, 20, of which the silencer walls 16, 20 located at the axial ends of the circumferential wall 12 form end walls that axially define the inner space 14 of the silencer, while the silencer wall 18 forms a partition wall dividing the inner space 14 of the silencer into two chambers 22, 24.

[0025] For example, a silencer pipe 26, acting as an inlet pipe, passes through the silencer walls 16, 18 and terminates in the silencer interior 14 in the region of chamber 24. A silencer pipe 28, acting as an outlet pipe, passes through the silencer walls 20, 18 and terminates in the silencer interior 14 in the region of chamber 20. A silencer pipe 30, positioned in the silencer interior 14, passes through the silencer wall 18 separating the two chambers 22, 24 and establishes a flow connection between the two chambers 24, 22 and thus also between the two silencer pipes 26, 28.

[0026] Using the silencer tube 30, which establishes the flow connection between the two chambers 22, 24, the connection of a silencer tube to a silencer wall by means of a bayonet fitting, which is generally referred to below as 32, is explained below as an example.

[0027] The silencer tube 30, which is connected or to be connected to the silencer wall 18 acting as an intermediate wall by means of the bayonet fitting 32, has a Fig. 2 To the left of the silencer wall 18 lies the first pipe section 34, which has a smaller outer dimension, i.e., a smaller outer diameter. For example, the first pipe section 34 can have a circular and cylindrical geometry. To the right of the silencer wall 18 lies a second pipe section 36 of the silencer pipe 30, the second pipe section 36 having a larger outer dimension, i.e., a larger outer diameter, than the first pipe section 34. The second pipe section 36 can also have a circular and, for example, cylindrical geometry.

[0028] In the direction of a pipe axis R between the first pipe section 34 and the second pipe section 36 lies an extension section 38 of the silencer pipe 30. In the axial extension area of ​​the extension section 38, the outer dimension of the silencer pipe 30 increases from the outer dimension in the first pipe section 34 to the outer dimension in the second pipe section 36. Correspondingly to this increase in the outer dimension, the inner dimension of the silencer pipe 30 also increases in the extension section 38.

[0029] In the silencer wall 18, a pipe passage opening, generally designated 40, is formed in relation to the silencer pipe 30. To provide the pipe passage opening 40, an opening edge 42 is formed on the silencer wall 18, bent or extending in the direction of the pipe axis R. This opening edge, corresponding to the outer circumferential contour of the silencer pipe 30 in the second pipe section 36, has a substantially cylindrical and circular shape and provides the pipe passage opening 40 with an inner dimension that corresponds substantially to the outer dimension of the silencer pipe 30 in the second pipe section 36.

[0030] In the silencer tube 30, bayonet fittings 44 are formed at several circumferential positions, for example at uniform intervals. For example, two, three, or four such bayonet fittings can be formed along the circumference around the tube axis R. As in Fig. 5In a simplified representation, each bayonet locking exception 44 has an insertion section 46 extending substantially in the direction of the tube axis R, which extends from the extension section 38 into the area of ​​the second tube section 36. For example, an insertion end 48 of the insertion section 46 can be positioned in the extension section 38 such that the insertion end 38 is located near the boundary of the extension section 38 with the first tube section 34 or adjacent to the first tube section 34. The insertion section 46 could also extend into the first tube section 34, so that the insertion end 48 is then positioned in the first tube section 34.

[0031] A transition section 52 of the bayonet fitting 44 connects to the insertion section 46 at its end 50, which is located, for example, in the region of the second pipe section 36. The transition section 52 can, for example, be curved or, in some areas, essentially straight and extending circumferentially around the pipe axis R. In an alternative embodiment, the transition section 52 could also be partially positioned in the expansion section 38 of the silencer pipe 30 or could be positioned entirely within the expansion section 38, for example, in the area where the expansion section 38 meets the second pipe section 36. However, for a defined radial positioning of the silencer pipe 30 in the pipe opening 40, the transition section 52 is advantageously located at least partially, and preferably entirely, within the second pipe section 36.

[0032] A locking section 56 of the bayonet lug receptacle 44 connects to the end 54 of the transition section 52 furthest from the insertion section 46. The locking section 56 can be designed to extend essentially parallel to the insertion section 46 and extends, as the Fig. 5 This shows, in the direction of the tube axis R in the same direction away from the transition section 52, so that basically the bayonet fitting 44 has an essentially U-shaped shape.

[0033] The locking section 56 has a locking end 58, which in the illustrated embodiment is located in the second pipe section 36. The locking section 56 could also extend partially into the extension section 38 of the silencer pipe 30, so that the locking end 58 is positioned in the extension section 38, for example, near the transition to the second pipe section 36. Furthermore, the locking section 56 could simply be provided by a circular radial bulge adjoining the transition section 52 or be formed by an end section of an arcuate transition section 52.

[0034] On the silencer wall 18, at least one bayonet locking projection 60 is formed in the area of ​​the pipe passage opening 40, projecting radially inwards into the pipe passage opening 40. Preferably, such a bayonet locking projection is provided on the silencer wall 18 in association with each bayonet locking receptacle 44 on the silencer pipe 30. As the Figs. 3 and 4As this clearly demonstrates, such a bayonet locking projection 60 can, for example, be provided by a radially inwardly oriented indentation at the opening edge 42. The circumferential extent of such a bayonet locking projection 60 is selected such that it is at least slightly smaller than the width of the insertion section 46 or the locking section 56 in the circumferential direction around the tube axis R, while its extent in the direction of the tube axis R is at least slightly smaller than the axial width of the transition section 52. In this way, it is ensured that such a locking section 60 can be moved through the insertion section 46 and the transition section 52 into the locking section 56 to establish the locking state.

[0035] To establish the locked position, the silencer tube 30, with its first tube section 34, is moved towards the silencer wall 18 or inserted into the tube opening 40 such that the bayonet locking projections 60 provided on the silencer wall 18 are each aligned circumferentially with the insertion section 46 of one of the bayonet locking receptacles 44. During this process, the silencer tube 30 is in a Fig. 2The movement in the recognizable direction B is directed towards the silencer wall 18. During this movement, the bayonet locking projections 60 provided on the silencer wall 18 engage in the insertion sections 46 of the bayonet locking receptacles 44, which extend in the expansion section 38 of the silencer tube 30 and are thus open axially towards the first tube section 34. The movement in the direction B can be continued until, as illustrated by a movement arrow P, a respective bayonet locking projection 60 reaches the area of ​​the transition from the insertion section 46 that receives it to the subsequent transition section 52.

[0036] Upon reaching this position, the silencer tube 30 is rotated relative to the silencer wall 18 in the tube axis R, so that a respective bayonet locking projection 60 moves along the transition section 52 into the area of ​​the locking section 56. Subsequently, or even during this rotational movement, the movement continues in the direction of movement B, so that a respective bayonet locking projection 60 moves into the Fig. 5 The position indicated by the dashed line at the locking end 58 of the associated bayonet fitting 44 is reached. In this state, further axial and circumferential movement of the silencer tube 30 is no longer possible, and it is thus positioned in a defined locking position of the bayonet fitting 32 with respect to the silencer wall 18.

[0037] Since the locking section 56 is axially shorter than the insertion section 46, and the locking end 58 is positioned either in the second pipe section 36 or in the extension section 38 close to the second pipe section 36, the silencer pipe 30 is positioned in the locked position relative to the silencer wall 18 such that the opening edge 42 overlaps the second pipe section 36 axially, at least in part. Because the inner dimension of the pipe passage openings in the area of ​​the opening edge 40 is matched to the outer dimension of the second pipe section 36 of the exhaust pipe 30, i.e., is only slightly larger than it, the bayonet fitting 32 positions the exhaust pipe 30 not only axially and circumferentially relative to the silencer wall 18, but also radially through the interaction of the second pipe section 30 with the opening edge 42.

[0038] To ensure that the silencer pipe 30 or the bayonet fitting 32 remains in the locked position under the vibrations occurring in a vehicle, further measures can be taken to create a firm connection between the silencer pipe 30 and the silencer wall 18. For example, when the locking position is reached during the assembly of the silencer, one or more welds, such as spot welds, can be created in the area where the silencer wall 18 meets the silencer pipe 30. Alternatively or additionally, the silencer pipe 30 can be radially expanded, at least in the section of its length passing through the pipe opening 40, so that it is pressed radially outwards against the silencer wall 18 or the opening edge 42. This expansion process can also create a slight radial widening of the opening edge.

[0039] The connection of the silencer tube 30 to the silencer wall 18 by means of the bayonet fitting 32, as described above, achieves such a stable positioning of the silencer tube 30 that no further support measures are required. Depending on the design of the silencer 10, however, it could also be provided that the silencer tube 30, for example, with its first tube section 34 and / or its second tube section 36, passes through another silencer wall acting as an intermediate wall in the silencer interior 14 and is supported therein at least radially. Furthermore, in the case of a multiply radially stepped design of the silencer tube 30, it could be connected to two or more correspondingly dimensioned silencer walls, each by means of such a bayonet fitting 32.

[0040] The silencer pipe 26, acting as an inlet pipe, and / or the silencer pipe 28, acting as an outlet pipe, could, for example, be connected to the silencer wall 18, acting as an intermediate wall, by means of such a bayonet fitting. A respective cylindrical section of the pipe could penetrate a pipe opening in the associated silencer wall 16 or 20 and be welded to it to create a gas-tight seal. In this case, welding in the area of ​​the bayonet fitting or radial expansion can be omitted. Furthermore, it is possible to position a silencer pipe acting as an inlet or outlet pipe essentially transversely to the silencer axis S through the circumferential wall 12.Inside the silencer chamber 14, a silencer wall acting as a support wall can be arranged extending essentially in the direction of the silencer axis S, into which such a silencer tube is positioned engaging. The connection between such a silencer tube and such a silencer wall acting as a support wall can be effected by means of a bayonet fitting 32 in the manner described above.

[0041] In configurations where gas leaks, for example between the two chambers 22, 24, are generally unproblematic or permissible, and where, if necessary, further openings are provided in the silencer wall 18 that allow gas passage, the bayonet fittings 44, as is particularly evident in the Fig. 2 , 3 and 4This can be seen as the silencer tube 30 or a tube wall thereof having slot-like receiving openings. If gas passage in the area of ​​the bayonet fitting 32 is to be largely prevented, the bayonet fitting receptacles 44 can be designed as radially inwardly directed receiving recesses or projections, similar to the bayonet fitting projections 60.

[0042] Although, for the sake of simplicity in carrying out the process of establishing the locking state in the bayonet fitting receptacles 44, at least the insertion section 46, and preferably also the locking section 56, extends in the direction of the tube axis R, these sections can be angled with respect to the tube axis R, for example in a V-shape to each other, so that the insertion of a respective bayonet projection 60 into an associated insertion section 46 or locking section 56 can include the movement in the direction of movement B accompanied by a rotation about the tube axis R.

[0043] In a further alternative embodiment, the bayonet locking projections 44 can, for example, be provided on the silencer wall 18 in the area of ​​the pipe passage opening 40 or the opening edge 42, and bayonet locking projections 60 can be formed on the silencer pipe 30, for example, as radially outwardly oriented projections. The design of the silencer pipe 30 with areas of different external dimensions is not required. The bayonet locking projections 44 can be arranged on the silencer wall 18 such that the insertion end 48 of the respective insertion section 46 is positioned in the rounded transition area from the opening edge 42 to a plate-like body area of ​​the silencer wall 18 and is thus axially open in the direction of the pipe axis R to receive a respective bayonet locking projection 60.The transition section 52 and the locking section 56 can then be formed essentially in the opening edge 42.

[0044] When manufacturing the silencer 10 using a coiled construction method, a silencer insert can be produced that encompasses all silencer walls, i.e., in the illustrated example, silencer walls 16, 18, 20, and all or some of the silencer tubes, i.e., in the illustrated embodiment, silencer tubes 26, 28, 30. During the assembly of this silencer insert, it is possible to connect one or more of the silencer tubes to at least one of the silencer walls by means of a bayonet fitting, as described above, and, where necessary, to create a material connection and / or a force connection between a respective silencer tube and a silencer wall through which it passes. Subsequently, the silencer insert produced in this way can be wrapped with the circumferential wall 12 or inserted into a circumferential wall 12 that is already designed as a tube-like component.The silencer walls 16, 20 of the illustrated embodiment, which act as end walls, can then be connected gas-tight to the circumferential wall 12 by forming, for example by crimping, and / or by material joining, for example by welding.

[0045] When such a silencer is used in the exhaust system of an internal combustion engine, its various components, in particular the silencer rod and the silencer wall, are advantageously designed as metal components, for example, sheet metal parts generated by forming, into which the structures required to provide a bayonet fitting can be easily incorporated. The principles of the present invention can also be applied, for example, to a silencer used in the exhaust system of an internal combustion engine, in which the various components are made of plastic, primarily for weight reduction reasons. The structures required to provide a bayonet fitting can also be easily incorporated into such plastic components.

Claims

1. Silencer for an exhaust system, comprising: - a circumferential wall (12) enclosing a silencer interior (14), - at least one silencer wall (18, 20) adjoining the circumferential wall (12) and / or arranged in the silencer interior (14), - at least one silencer tube (26, 28, 30) extending in the direction of a tube axis (R) and passing through a tube opening (40) in at least one silencer wall (16, 18, 20), wherein at least one silencer tube (30) passing through a tube opening (40) in a silencer wall (18) is connected to the silencer wall (18) by means of a bayonet fitting (32).

2. Silencer according to claim 1, characterized by the fact thatThe bayonet fitting (32) in one component of the silencer tube (30) and silencer wall (18), preferably in the silencer tube (30), comprises at least one bayonet fitting receptacle (44) and on the other component of the silencer tube (30) and silencer wall (18), preferably on the silencer wall (18), comprising a bayonet fitting projection (60) in association with at least one, preferably each, bayonet fitting receptacle (44), preferably wherein the bayonet fitting (32) comprises a plurality of bayonet fitting receptacles (44) arranged around the tube axis (R) with preferably uniform spacing from one another.

3. Silencer according to claim 2, characterized by the fact thatthe bayonet fitting receptacle (44) comprises an insertion section (46) extending substantially in the direction of the tube axis (R) and open in the direction of the tube axis (R) to receive a bayonet fitting projection (60), a transition section (52) adjoining the insertion section (46) and extending substantially circumferentially, and a locking section (56) adjoining the transition section (52) and extending substantially in the direction of the tube axis (R) and closed in the direction of the tube axis (R).

4. Silencer according to one of claims 1-3, characterized by the fact that the silencer pipe (30) comprises a first pipe section (34) with a smaller outer dimension, a second pipe section (36) with a larger outer dimension and an extension section (38) between the first pipe section (34) and the second pipe section (36).

5. Silencer according to claim 4, insofar as it refers back to claim 3, characterized by the fact thatthe insertion section (46) extends in the expansion section (46) in the direction away from the first pipe section towards the second pipe section (36), preferably wherein an insertion end (48) of the insertion section (46) is positioned in the expansion section (38) near the first pipe section (34).

6. Silencer according to claim 5, characterized by the fact that the transition section (52) is positioned in the extension section (38) near the second pipe section (36) and / or in the second pipe section (36).

7. Silencer according to one of claims 4-6, characterized by the fact that a locking end (58) of the locking section (56) is positioned in the second pipe section (36) or in the extension section (38) near the second pipe section (36).

8. Silencer according to claim 2 or one of claims 3-7, insofar as it refers back to claim 2, characterized by the fact thatwhich includes at least one bayonet fitting (44) forming a receiving opening in a tube wall of the silencer tube (30).

9. Silencer according to claim 2 or one of claims 3-7, insofar as it refers back to claim 2, characterized by the fact that which includes at least one bayonet fitting (44) forming a receiving recess in a tube wall of the silencer tube (30).

10. Silencer according to claim 2 or one of claims 3-9, insofar as it refers back to claim 2, characterized by the fact that the silencer wall (18) comprises an opening edge (42) surrounding the pipe passage opening (40) and bent in the direction of the pipe axis (R), and the bayonet locking projection (60) comprises a radially inwardly directed shape on the opening edge (42).

11. Silencer according to one of claims 1-10, characterized by the fact thatthe at least one silencer tube (30) connected to a silencer wall (18) by means of a bayonet fitting (32) is further connected to the silencer wall (18) by material connection, preferably one or more welds, and / or by force connection, preferably by radial expansion of the silencer tube (30) in the section of the silencer tube (30) passing through the tube opening (40) of the silencer wall (18).

12. Silencer according to one of claims 1-11, characterized by the fact that the silencer wall (18) is a partition separating two chambers (24, 26) in the silencer interior (14).

13. Method for manufacturing a silencer according to any one of claims 1-12, comprising the following measures: a) providing at least one component of silencer tube (30) and silencer wall (18), preferably the silencer tube (30), with at least one bayonet fitting receptacle (44), b) providing the other component of silencer tube (30) and silencer wall (18), preferably the silencer wall (18), with at least one bayonet fitting projection (60), c) inserting the at least one silencer tube (30) into the tube passage opening (40) of the at least one silencer wall (18) such that each bayonet fitting projection (60) on the other component of silencer tube (30) and silencer wall (18) is received in a bayonet fitting receptacle (44) of the one component of silencer tube (30) and silencer wall (18).

14. Method according to claim 13, characterized by the fact thatfurthermore, a measure d) is provided for the material-fit connection of the at least one silencer tube (30) with the at least one silencer wall (18) after carrying out measure c), or / and furthermore, a measure e) is provided for the force-fit connection of the at least one silencer tube (30) with the at least one silencer wall (18) after carrying out measure c), preferably wherein measure d) comprises the creation of at least one weld.

15. Method according to claim 14, characterized by the fact that the measure e) comprises the radial widening of the at least one silencer tube (30) in its axial area passing through the tube opening (40) of the at least one silencer wall (40).

Images