Muffler and method for manufacturing a muffler

Abstract

The invention relates to a muffler for an exhaust device of an internal combustion engine, comprising: a muffler housing (14) having a circumferential wall (16) extending in a direction along a housing longitudinal axis (L) and end walls (22, 24) at each axial end region (18, 20) of the circumferential wall; a muffler insert (26) surrounded by the circumferential wall and supported on the circumferential wall, having at least one holding wall (46) extending substantially in the direction of the housing longitudinal axis (L); at least one first exhaust guide pipe (44), the at least one first exhaust guide pipe having a first pipe end region (62) positioned and fixed in a circumferential wall opening (66) in the circumferential wall and having a second pipe end region held on the at least one holding wall, characterized in that the at least one first exhaust guide pipe is held on the holding wall in its second pipe end region (64) by force fit or snap fit.

Description

Field of the Invention

[0001] The invention relates to a muffler for an exhaust gas device of an internal combustion engine, in particular in a motor vehicle, and a method for manufacturing a muffler. Background Art

[0002] A muffler is known from EP1888891B2. In this known muffler, a muffler insert is constructed, which has two intermediate walls spaced apart from each other in the direction of the longitudinal axis of the muffler housing and a retaining wall is received between them. The muffler insert is surrounded by a circumferential wall extending in the direction of the longitudinal axis of the housing. The circumferential wall openings constructed in the circumferential wall are positioned such that the circumferential wall openings are opposed to the retaining wall openings formed in the retaining wall. In this known muffler, an exhaust gas guiding pipe of an inlet pipe is introduced into the muffler housing from the outside through the circumferential wall opening such that the exhaust gas guiding pipe is positioned in the region of the circumferential wall with a first pipe end region and is fixed to the circumferential wall by welding in this region. The second pipe end region of the exhaust gas guiding pipe is positioned to be inserted into or penetrate through the retaining wall opening and is connected to the retaining wall by a form-fit generated via mechanical forming. Summary of the Invention

[0003] The object of the invention is to provide a muffler for an exhaust gas device of an internal combustion engine and a method for manufacturing a muffler, by means of which a simple and yet stable construction can be achieved.

[0004] According to a first aspect of the invention, the object is solved by a muffler for an exhaust gas device of an internal combustion engine, the muffler comprising:

[0005] a muffler housing having a circumferential wall extending in the direction of the longitudinal axis of the housing and end walls at each axial end region of the circumferential wall;

[0006] a muffler insert surrounded by the circumferential wall and supported on the circumferential wall, the muffler insert having at least one retaining wall extending substantially in the direction of the longitudinal axis of the housing;

[0007] at least one first exhaust gas guiding pipe, the at least one first exhaust gas guiding pipe being positioned with a first pipe end region to be inserted into a circumferential wall opening in the circumferential wall and fixed to the circumferential wall and being held on the at least one retaining wall with a second pipe end region.

[0008] The at least one first exhaust gas guiding pipe is held on the retaining wall by a force fit or a snap fit in its second pipe end region.

[0009] In the muffler according to the invention, the first exhaust gas guide pipe is not held on the holding wall by shaping and thus by the form-fit generated by shaping between the exhaust gas guide pipe and the holding wall, but by means which make shaping of the first exhaust gas guide pipe and the holding wall unnecessary when the exhaust gas guide pipe is moved into its installation position or afterwards. The shaping required for achieving a force fit, i.e., the holding action by the frictional force acting between the first exhaust gas guide pipe and the holding wall, and also for achieving a snap fit is provided before assembly. During assembly, the components to be held on one another, i.e., the at least one first exhaust gas guide pipe and the holding wall, only move relative to one another. During this movement, for example, a slight deformation of the holding wall, but completely within the elastic range, can occur to achieve a force fit. Also, for example, a deformation of the holding wall within the elastic range can temporarily occur when establishing a snap fit. However, such a deformation occurring within the elastic range of the components involved does not result in a new shaped form of the relevant components and thus the generation of a form-fit, in particular not a shaping produced by acting on these components with a tool after the two components have been placed in their relative positioning required for the construction.

[0010] To achieve a gas-tight closure of the muffler to the outside, the at least one first exhaust gas guide pipe can be connected to the circumferential wall by welding.

[0011] The at least one first exhaust gas guide pipe can be an inlet pipe through which exhaust gas is introduced into the interior of the muffler.

[0012] To provide a stable holding interaction between the holding wall and the at least one first exhaust gas guide pipe, it is proposed that a holding wall opening at least partially surrounded by a bent fixing edge region of the at least one holding wall is provided in the at least one holding wall in a manner assigned to the at least one first exhaust gas guide pipe, and the at least one first exhaust gas guide pipe is positioned with its second pipe end region to be inserted into the holding wall opening and is held in the region of the fixing edge region in the holding wall opening by a press fit. When the first exhaust gas guide pipe is introduced into the holding wall opening surrounded by the fixing edge region, the fixing edge region can be slightly radially expanded within the range of its elastic deformability, and thus the frictional force of the force fit can be effectively provided by pre-tightening the fixing edge region against the outer surface of the exhaust gas guide pipe.

[0013] Depending on the direction in which the at least one first exhaust gas guide tube moves relative to the at least one retaining wall during assembly, the fixed edge region can be bent in the direction of the first tube end region of the at least one first exhaust gas guide tube, or the fixed edge region can be bent away from the first tube end region of the at least one first exhaust gas guide tube. Preferably, the fixed edge region is bent in the direction in which the at least one first exhaust gas guide tube moves relative to the retaining wall. Thereby, tilting of the fixed edge region can be avoided or the at least one first exhaust gas guide tube can be easily introduced into the retaining wall opening surrounded by the fixed edge region.

[0014] For a stable form-fit between the at least one first exhaust gas guide tube and the at least one retaining wall, a circumferentially completely surrounding abutting contact between the at least one first exhaust gas guide tube and the at least one retaining wall can be provided in the region of the retaining wall opening provided on the at least one retaining wall in a manner assigned to the at least one first exhaust gas guide tube.

[0015] The introduction of the at least one first exhaust gas guide tube into the assigned retaining wall opening can be carried out more easily if a circumferentially interrupted abutting contact between the at least one first exhaust gas guide tube and the at least one retaining wall is provided in the region of the retaining wall opening provided on the at least one retaining wall in a manner assigned to the at least one first exhaust gas guide tube, for providing a form-fit between the at least one first exhaust gas guide tube and the at least one retaining wall.

[0016] For this purpose, for example, it can be provided that in the at least one retaining wall, in the region of the retaining wall opening provided on the at least one retaining wall in a manner assigned to the at least one first exhaust gas guide tube, at least one, preferably a plurality of, circumferentially spaced-apart wall interruption regions opening towards the retaining wall opening, preferably slit-shaped, are provided. Thus, a plurality of tongues acting on the form-fit and succeeding one another circumferentially and separated from one another by the wall interruption regions are provided on the retaining wall, which tongues can be elastically deformed relatively easily when the first exhaust gas guide tube is introduced.

[0017] To provide a snap lock, a locking formation can be provided on the second tube end region of the at least one first exhaust gas guide tube, and a mating locking formation in locking engagement with the locking formation can be provided on the at least one retaining wall in a manner assigned to the locking formation.

[0018] In a design for avoiding a volume contraction of the exhaust gas flow in the at least one first exhaust gas guide tube, it is proposed that the locking formation includes at least one locking projection radially protruding outwards with respect to the tube longitudinal axis of the at least one first exhaust gas guide tube.

[0019] According to the design of the mating locking formation, the locking formation may include at least two locking protrusions successively arranged in the direction of the tube longitudinal axis, and / or the locking formation may include at least two locking protrusion segments successively arranged in the circumferential direction around the tube longitudinal axis.

[0020] If at least one, preferably each, locking protrusion is provided by the convex protrusion formation of the at least one first exhaust guide tube, then the locking formation can be provided for the at least one first exhaust guide tube in a simple manner. However, the required shaping of the exhaust guide tube is carried out in a processing stage different from the prior art before the exhaust guide tube is integrated into the muffler, in which the exhaust guide tube can be easily operated as a separate component.

[0021] In the at least one retaining wall, retaining wall openings may be provided in a manner allocated to the at least one first exhaust guide tube. In the at least one retaining wall, a plurality of wall interruption regions, which are arranged at a circumferential spacing from each other around the retaining wall opening and open towards the retaining wall opening, preferably in a slit-like manner, may also be provided. And a locking tongue of the mating locking formation may be formed between at least two wall interruption regions directly successively arranged in the circumferential direction.

[0022] To establish the locked state, at least one, preferably each, locking tongue of the mating locking formation may be fitted between two locking protrusions successively arranged in the direction of the tube longitudinal axis of the locking formation.

[0023] In another design, on at least one, preferably each, locking tongue, a locking recess for receiving at least one locking protrusion of the locking formation may be provided.

[0024] To avoid mutual abutment between the retaining wall and the first exhaust guide tube within an acute angle range, it is proposed that in the at least one retaining wall, in at least one, preferably each, locking tongue, a curved locking tongue edge region is provided.

[0025] If the locking formation has two locking protrusions arranged at an axial spacing from each other, at least one, preferably each, locking tongue edge region may be fitted between two locking protrusions successively arranged in the direction of the tube longitudinal axis of the locking formation.

[0026] In an alternative design, at least one locking recess may be provided in at least one, preferably each, locking tongue edge region.

[0027] The muffler insert may include at least two intermediate walls that are disposed substantially orthogonally to the longitudinal axis of the housing and supported on the circumferential wall, and the at least one retaining wall is fixed to one of the intermediate walls in each of its two opposite end regions.

[0028] The muffler insert may further include at least one second exhaust guide tube, preferably a discharge tube, and an intermediate wall opening is provided in at least one of the intermediate walls connected to the at least one retaining wall and an end wall opening is provided in one of the end walls in a manner that is adapted to the at least one second exhaust guide tube. The at least one second exhaust guide tube is positioned to be inserted into the intermediate wall opening and the end wall opening and is fixed by material locking on the end wall having the end wall opening in the region of the end wall opening and / or on the intermediate wall having the intermediate wall opening in the region of at least one intermediate wall opening.

[0029] According to another aspect, the above-mentioned task is solved by a method for manufacturing an exhaust muffler, in particular according to the present invention, the method including the following measures:

[0030] a) Providing at least one muffler insert having at least one retaining wall and at least one retaining wall opening in the at least one retaining wall,

[0031] b) Providing at least one first exhaust guide tube,

[0032] c) Surrounding the at least one muffler insert with the circumferential wall of the muffler housing, and a circumferential wall opening is provided in the circumferential wall in a manner that is adapted to the at least one retaining wall opening,

[0033] d) The at least one first exhaust guide tube is arranged such that the first tube end region of the at least one first exhaust guide tube is positioned to be inserted into the circumferential wall opening provided in a manner that is adapted to the at least one retaining wall opening and the second tube end region of the at least one first exhaust guide tube is held in the at least one retaining wall opening by form fit or snap fit,

[0034] e) Connecting the at least one first exhaust guide tube to the circumferential wall by material locking in the region of the circumferential wall opening.

[0035] The positioning of the at least one first exhaust gas guide pipe with its first pipe end region in the assigned circumferential wall opening can be implemented particularly simply in the following case, namely, in measure a), the at least one first exhaust gas guide pipe is positioned so as to be inserted into the at least one retaining wall opening, and in measure d), the at least one first exhaust gas guide pipe is first moved from the inside in the direction of the circumferential wall opening with its first pipe end region until the first pipe end region is positioned so as to be inserted into the circumferential wall opening and the second pipe end region is held on the at least one retaining wall in a form-fitting or snap-locking manner so as to be inserted into the at least one retaining wall opening. Here, the circumferential wall formed to provide the circumferential wall opening can play a funneling role, and the funneling role guides the first pipe end region into the circumferential wall opening.

[0036] In an alternative operating mode, in measure d), the at least one first exhaust gas guide pipe can be first moved from the outside through the circumferential wall opening in the direction of the at least one retaining wall with its second pipe end region until the first pipe end region is positioned so as to be inserted into the circumferential wall opening and the second pipe end region is held on the at least one retaining wall in a form-fitting or snap-locking manner so as to be inserted into the at least one retaining wall opening. In this operating mode, the at least one first exhaust gas guide pipe can be easily operated from the outside of the muffler housing.

[0037] In measure a), the at least one muffler insert can be provided such that the at least one retaining wall is connected to the intermediate wall in each of its two opposite end regions.

[0038] In measure c), the at least one muffler insert can also be surrounded by the circumferential wall by winding a plate-shaped circumferential wall blank around the at least one muffler insert. In an alternative operating mode, in measure c), the at least one muffler insert can be surrounded by providing a circumferential wall having a circumferentially closed structure and by pushing the at least one muffler insert into the circumferential wall provided with a circumferentially closed structure.

[0039] In order to close the muffler housing at its axial end regions, measure f) can be provided for fixing the end wall to each axial end region of the circumferential wall longitudinally extending in the direction of the housing longitudinal axis by material locking or / and form locking before or after implementing measure c).

[0040] The invention also relates to an exhaust gas device for an internal combustion engine, which exhaust gas device includes at least one muffler constructed according to the invention, and the muffler is preferably manufactured by a method according to the invention. Description of the Drawings

[0041] The present invention will now be described in detail with reference to the accompanying drawings. In the drawings:

[0042] Figure 1 A perspective view showing a muffler insert is shown;

[0043] Figure 2 The muffler having the muffler insert is shown when the circumferential wall of the muffler housing is partially cut away and shown; Figure 1 ... of the muffler insert;

[0044] Figure 3 Shows Figure 2 A perspective view of an exhaust guide pipe of the muffler held on a holding wall;

[0045] Figure 4 Shows Figure 2 Another perspective view of an exhaust guide pipe of the muffler held on a holding wall;

[0046] Figure 5 Shows Figure 2 A manufacturing stage of the muffler, in which the exhaust guide pipe has not yet been positioned to be inserted into the circumferential wall opening;

[0047] Figure 6 Shows a diagram corresponding to Figure 5 ... in which the exhaust guide pipe is positioned to be inserted into the circumferential wall opening;

[0048] Figure 7 Shows a diagram corresponding to Figure 2 ... in an alternative design form of the muffler;

[0049] Figure 8 Shows Figure 7 The holding wall of the muffler;

[0050] Figure 9 Different design forms of the exhaust guide pipe held on the holding wall by latching are shown in FIGS. a), b) and c) thereof;

[0051] Figure 10 Shows a cross-sectional view of the design form shown in Figure 9 a). Detailed Description of the Preferred Embodiment

[0052] In Figure 1 ..., for example, a muffler integrated as a transverse muffler in an exhaust device 10 of an internal combustion engine in a vehicle is generally designated by 12. The muffler 12 includes a muffler housing 14 having a circumferential wall 16 that extends longitudinally in the direction of the housing longitudinal axis L and surrounds the housing longitudinal axis L. At two axial end regions 18, 20 of the circumferential wall 16, end walls 22, 24 are fixed to the circumferential wall. The circumferential wall 16 and the end walls 22, 24 are provided, for example, as sheet metal formed parts.

[0053] Inside the muffler housing 14, there is arranged a muffler insert generally designated by 26. The muffler insert includes, in the illustrated exemplary design, four intermediate walls 28, 30, 32, 34, which can also be seen in Figure 2 and which are configured, for example, as sheet metal formed parts. The intermediate walls divide the interior space of the muffler housing 14 into five successively arranged chambers 36, 38, 40, 42, 44 in the direction of the longitudinal axis L of the housing. Here, openings can be provided in the intermediate walls 28, 30, 32, 34, via which the chambers 36, 38, 40, 42, 44 can communicate with one another.

[0054] The muffler insert 26 also includes a retaining wall 46, which extends substantially in the direction of the longitudinal axis L of the housing and is oriented substantially orthogonally with respect to the intermediate walls 28, 30, 32, 34 and which is configured, for example, as a sheet metal formed part. The retaining wall 46 is connected, at its two axial end regions 48, 50, to two intermediate walls 30, 32, for example, by welding.

[0055] In Figure 1 the muffler 12, there is also arranged a first exhaust gas guide pipe 44, which provides an inlet pipe, through which the exhaust gas is guided into the chamber 40 in the muffler housing 14. To discharge the exhaust gas from the muffler housing 14, there are arranged two second exhaust gas guide pipes 52, 54, each of which provides a discharge pipe. Intermediate wall openings are provided in each of the intermediate walls 28, 30, 32, 34 in a manner assigned to each of the second exhaust gas guide pipes 52, 54. Each intermediate wall opening can be surrounded by a bent fixing edge region formed on the respective intermediate wall, into which the respective second exhaust gas guide pipe 52, 54 is pushed. Advantageously, in each such fixing edge region or in the region of each intermediate wall opening, the respective second exhaust gas guide pipe 52, 54 can be fixedly connected to the respective intermediate wall 28, 30, 32, 24 by material locking, in particular material locking for welding. Here, a circumferential weld seam can be provided, or individual welding points can be provided to effect the fixed connection.

[0056] An end wall opening is provided in the end wall 22 which is arranged in the axial end region 18 of the circumferential wall 16 in such a way as to be assigned to the second exhaust gas guide pipe 52, and the second exhaust gas guide pipe 52 is positioned so as to be inserted into the end wall opening. In the region of this end wall opening, for example, a fixed edge region which is bent outwards can be provided on the end wall 22. The second exhaust gas guide pipe 52 can be connected to the end wall 22 in the region of this fixed edge region by a preferably circumferential weld seam. Similarly, an end wall opening surrounded by an outwardly bent fixed edge region is formed in the end wall 24 which is arranged on the axial end region 20 of the circumferential wall 16, and the second exhaust gas guide pipe 54 is positioned so as to be inserted into the end wall opening. Here too, a completely circumferential welded connection for gas-tightly closing between the second exhaust gas guide pipe 54 and the end wall 24 can be formed.

[0057] Inside the muffler housing 14, the second exhaust gas guide pipes 52, 54 can have openings via which the second exhaust gas guide pipes are open to different chambers 36, 38, 40, 42, 44. Inside the muffler housing 14, additional pipes can also be provided which provide connections between the different chambers 36, 38, 40, 42, 44. Thus, for example, a Helmholtz resonator can be provided by means of a pipe 56 which otherwise leads into the closed chamber 44. In principle, it should be noted that the internal structure of the muffler 12 is only shown by way of example and can be implemented differently in different aspects, for example with regard to the number of intermediate walls, chambers, pipes and also the routing of the pipes as compared to that shown in the drawings.

[0058] Subsequently, an explanation will be given of how the first exhaust gas guide pipe 44 is integrated into the muffler 12 or how the integration of the first exhaust gas guide pipe 44 into the muffler 12 is carried out. For this purpose, reference will subsequently be made to Figures 3 to 6 A first design variant will be explained in more detail.

[0059] Figure 3 and Figure 4 The retaining wall 46 and the first exhaust gas guide pipe 44 are shown in the pre-assembled state, that is, before the muffler insert 26 is surrounded by the circumferential wall 16. It can be seen in Figures 3 to 6 that, for example, a retaining wall opening 58 is formed in the retaining wall 46 in its central region. A fixed edge region 60 which preferably completely surrounds the retaining wall opening 58 is provided on the retaining wall 46 so as to surround the retaining wall opening 58. The fixed edge region 60 is bent from the retaining wall 46, for example by forming a through-draft, and has a substantially cylindrical structure.

[0060] The first exhaust gas guide pipe 44 has two pipe end regions 62, 64. Before surrounding the muffler insert 26 with the circumferential wall 16, the first exhaust gas guide pipe 44 is inserted into the retaining wall opening 58 in such a way that the first exhaust gas guide pipe 44 is positioned in the retaining wall opening 58 in the region of its second pipe end region 64. The first exhaust gas guide pipe 44 can, for example, be introduced into the retaining wall opening 58 in the positioning shown in Figure 3 and Figure 4 before connecting the retaining wall 46 to the two intermediate walls 30, 32, so that this process can be carried out without being disturbed by the second exhaust gas guide pipes 52, 54 also provided on the muffler insert 26.

[0061] When introducing the first exhaust gas guide pipe 44 into the retaining wall opening 58, the first exhaust gas guide pipe 44 can be moved in the direction of introduction with its first pipe end region 62, and the fixing edge region 60 extends from the retaining wall 46 in the direction of introduction. Thus, the rounded transition formed during the manufacture of the fixing edge region 60 between the substantially planar region of the retaining wall 46 and the fixing edge region 60 can be used as an introduction bevel.

[0062] The internal dimensions of the retaining wall opening 58 or the fixing edge region 60 and the external dimensions of the first exhaust gas guide pipe 44, which is, for example, substantially cylindrical in shape, are coordinated with each other such that the first exhaust gas guide pipe 44 is held in the retaining wall opening 46 by press fit or by the fixing edge region 60. When introducing the first exhaust gas guide pipe 44 into the retaining wall opening 58, the fixing edge region 60 is slightly radially expanded within the range of its elastic deformability, so that the fixing edge region is pressed onto the outer peripheral surface of the first exhaust gas guide pipe 44 under prestress. Thus, a form-fitting, i.e., a holding action generated by frictional interaction, is produced between the first exhaust gas guide pipe 44 and the retaining wall 46, which form-fitting prevents unintentional movement of the first exhaust gas guide pipe 44 with respect to the retaining wall 46 but in principle allows mobility of the first exhaust gas guide pipe 44 with respect to the retaining wall 46 in the direction of the pipe longitudinal axis R of the first exhaust gas guide pipe and in the circumferential direction around the pipe longitudinal axis R, i.e., rotational movement.

[0063] The muffler insert 26 supplemented by the first exhaust gas guide pipe 44 in this way and method is then surrounded by the circumferential wall 16. For this purpose, for example, it can be carried out such that first the plate-shaped blank of the circumferential wall 16 is provided with a circumferential wall opening 66 assigned to the retaining wall opening 58. The circumferential wall opening 66 can also be provided by hemming, so that an outwardly directed fixing edge region 68 is produced in the region of the circumferential wall opening 66. The plate-shaped blank provided with the circumferential wall opening 66 can then be bent into a tubular closed structure and connected, for example, by welding or / and hemming etc. in its two edge regions that are then adjacent to each other.

[0064] Then the muffler insert 26 is introduced into the circumferential wall 16 provided in such a way as to be circumferentially closed along the direction of the housing longitudinal axis L until the installation position of the muffler insert is reached and the wall opening 58 is positioned in the region of the circumferential wall opening 66 along the direction of the housing longitudinal axis L. In this state, the first exhaust gas guide pipe 44 is opposed to the circumferential wall opening 66 with its first pipe end region 62 on the inner side of the circumferential wall 16.

[0065] In a subsequent working step, a tool is inserted into the first exhaust gas guide pipe 44 and the first exhaust gas guide pipe is moved along the movement direction B with its first pipe end region 62 first moving or being pulled towards the circumferential wall opening 66 or the fixed edge region 68 surrounding the circumferential wall opening. Here, the first exhaust gas guide pipe 44 moves with its second pipe end region 64 in the retaining wall opening 58 until the state shown in Figure 6 is reached, in which the first pipe end region 62 is positioned to be inserted into the circumferential wall opening 66 and is thus surrounded by the fixed edge region 68 and the second pipe end region 64 is positioned to be inserted into the retaining wall opening 58 and is surrounded by the fixed edge region 60 and is held in the retaining wall opening 58 by force fit as already described.

[0066] Therefore, the process of moving the first exhaust gas guide pipe 44 along the movement direction B for introducing the first pipe end region 62 into the circumferential wall opening 66 can be implemented relatively easily because the circumferential wall 16 also provides an insertion bevel with its curved transition region to the fixed edge region 68, through which the first pipe end region 62 is guided into the circumferential wall opening 66, and because the fixed edge region 60 also bends on the retaining wall 46 in the direction towards the circumferential wall opening 66 or the first pipe end region 62, i.e., bends along the movement direction of the first exhaust gas guide pipe 44, in order to introduce the first pipe end region 62 into the circumferential wall opening 66. Therefore, there is no danger that acute-angle regions of the retaining wall 46 or the circumferential wall 16 will be inclined on the outer surface of the first exhaust gas guide pipe 44 either in the region of the retaining wall opening 58 or in the region of the circumferential wall opening 66.

[0067] The circumferential wall opening 66 can be dimensioned such that a force fit with the first exhaust gas guide pipe 44 of the first pipe end region 62 is also generated there when the first exhaust gas guide pipe is introduced into the circumferential wall opening 66. Alternatively or additionally, the circumferential wall opening 66 can be designed with a slight interference with respect to the outer dimensions of the first exhaust gas guide pipe 44 in its first pipe end region 66, so that the first exhaust gas guide pipe 44 is received with a small movement clearance in the circumferential wall opening 66 or the fixed edge region 68 with its first pipe end region 62.

[0068] After the first exhaust gas guide pipe 44 is introduced into the circumferential wall opening 66 in such a way that the first exhaust gas guide pipe 44 is substantially flush with the fixing edge region 68 or projects slightly outward from the fixing edge region with its first pipe end region 62, for example, in the direction of the pipe longitudinal axis R, the first exhaust gas guide pipe 44 can be connected to the circumferential wall 16 in the region of the fixing edge region 68 by a weld seam that preferably completely surrounds it in the circumferential direction in order to ensure a gas-tight closure. In this process, for example, another exhaust gas guide pipe can already be inserted into the first exhaust gas guide pipe 44 and thus joined to the first exhaust gas guide pipe 44 or the circumferential wall 16 by the same weld seam.

[0069] In the subsequent workflow, the two end walls 22, 24 can then be arranged on the axial end regions 18, 20 of the circumferential wall 16 and fixed and gas-tightly connected to the circumferential wall by welding or / and by form-fitting, for example crimping. Here, the second exhaust gas guide pipes 52, 54 passing through or inserted into the respective end wall openings can also be fixed by respectively surrounding weld seams and gas-tightly connected to the end walls 22, 24.

[0070] In the muffler 12 manufactured in the manner and method described previously, the first exhaust gas guide pipe 44 is stably held in the circumferential wall 16 or the holding wall 46 in its two pipe end regions 62, 44 and thus held on the muffler insert 26, in particular against offset movements transverse to the pipe longitudinal axis R. Since the first exhaust gas guide pipe 44 is reliably held against displacement in the direction of the pipe longitudinal axis R by welding the first exhaust gas guide pipe 44 to the circumferential wall 16 in the first pipe end region 62, it is possible to dispense with shaping the first exhaust gas guide pipe 44 in its second pipe end region 64, which is in interaction with the holding wall 46, after it has been placed in the Figure 6 mounting position shown in such a way that a form-fit preventing movement in the direction of the pipe longitudinal axis R is also produced between the holding wall 46 and the first exhaust gas guide pipe 44 in this region. Nevertheless, it should be noted that the force fit generated between the holding wall 46 and the first exhaust gas guide pipe 44 also assists in supporting the defined axial holding of the first exhaust gas guide pipe 44 in the muffler 12 in the direction of the pipe longitudinal axis R.

[0071] Figure 7 and Figure 8 show a variant of the previously described design of the muffler 12. In Figure 7 and Figure 8It can be seen that in the holding wall 46, a plurality of slit-shaped wall interruption regions 70 are provided, which extend substantially radially with respect to the holding wall opening 58 or the opening central axis M. A holding wall tongue 72 is formed between every two such wall interruption regions 70 in the circumferential direction around the opening central axis M. Since a total of four slit-shaped wall interruption regions 70 are provided in the illustrated design example and the wall interruption regions open radially inwards towards the holding wall opening 58, four such holding wall tongues 72 surrounding the holding wall opening 58 are provided.

[0072] The wall interruption region 70 extends into the region of the fixing edge region 60 and thus also interrupts the fixing edge region in the circumferential direction, so that the fixing edge region 60 provides a holding wall tongue edge region 74 in a manner assigned to each holding wall tongue 72.

[0073] In the design shown in the holding wall 46 between Figure 7 and Figure 8 the fixing edge region 60 is arranged on the holding wall 46 such that it extends in the muffler insert 26 surrounded by the circumferential wall 16 away from the direction of the circumferential wall opening 66 provided in the circumferential wall 16 as shown in Figure 5 and Figure 6 When assembling the muffler 12, after the muffler insert 26 is surrounded by the circumferential wall 16, the first exhaust gas guiding tube 44 can be moved with its second tube end region 64 first from the outside through the circumferential wall opening 66 towards the holding wall 46 until the second tube end region 64 enters the holding wall opening 58 or is introduced into the holding wall opening under press fit. Here, the holding wall tongue 72 can be deflected within the range of its elastic deformability or moved in the movement direction of the first exhaust gas guiding tube 44, whereby the fixing edge region 60 slightly radially spreads with its holding wall tongue edge region 74 and is pressed onto the outer peripheral surface of the first exhaust gas guiding tube 44 from the radially outside due to the elasticity of the holding wall 46. Thereby, a holding action is also generated by force locking, that is, by the frictional interaction between the first exhaust gas guiding tube 44 and the holding wall 46 and thus the muffler insert 26.

[0074] Subsequently, the first exhaust gas guiding tube 44 can be fixed to the circumferential wall 16 in the region of its first tube end region 62 in the manner and method described above in the region of the circumferential wall opening 66 or the fixing edge region 68.

[0075] It should be noted that also in Figure 7 and Figure 8In the design shown, the fixed edge region 60 may be arranged on the retaining wall 46 such that the fixed edge region extends in the direction of the circumferential wall opening 66 provided in the muffler insert 26 surrounded by the circumferential wall 16. In this design, the first exhaust gas guide pipe 44 can then be arranged on the retaining wall 46 in a manner corresponding to Figure 5 before the muffler insert 26 with the first exhaust gas guide pipe 44 already arranged thereon is surrounded by the circumferential wall 16. The first exhaust gas guide pipe 44 can then in turn move from the inside in the movement direction B shown in Figure 5 with its first pipe end region 62 and first move through the circumferential wall opening 66 or move into the circumferential wall opening and then be fixedly connected to the circumferential wall 16 by welding. Similarly, in the design shown in reference Figures 3 to 6 the fixed edge region 60 on the retaining wall 46 may be curved such that the fixed edge region extends in a direction away from the circumferential wall opening 66 provided therefor. In this design, the first exhaust gas guide pipe 44 can then be introduced from the outside with its second pipe end region 64 first through the circumferential wall opening 66 and then into the retaining wall opening 58 after the muffler insert 26 has been surrounded by the circumferential wall 16. It can thus be seen that: Advantageously, the fixed edge region 60 which mainly contributes to producing a form-fitting connection between the retaining wall 46 and the first exhaust gas guide pipe 44 is arranged on the retaining wall 46 curved in the direction of movement of the first exhaust gas guide pipe 44 in order to position the first pipe end region 62 of the first exhaust gas guide pipe in the circumferential wall opening 66.

[0076] It should also be noted that the process of surrounding the muffler insert 46 with the circumferential wall 16 can also be carried out in another way. The circumferential wall blank provided as a plate-shaped blank and provided with the circumferential wall opening 66 or the fixed edge region 68 may, for example, be positioned or wound around the muffler insert 26 after it has been pre-bent into a curved or tubular structure, and then the circumferential wall blanks are connected to one another in the adjacent edge regions by welding or / and by form-fitting in order to provide a circumferentially closed structure. The two end walls 22, 24 may also already be arranged on the muffler insert before the muffler insert 26 is surrounded by the circumferential wall 16 and are connected to the circumferential wall 16 in its two axial end regions 18, 20 when the muffler insert 26 is positioned in the circumferential wall 16 or in the interior of the muffler housing 14 by being pushed into the circumferentially closed structure of the circumferential wall 16 or by being surrounded by the circumferential wall 16 which is initially still open in the circumferential direction.

[0077] Reference Figure 9 and Figure 10Subsequently, an alternative design is described, which enables the first exhaust gas guide pipe 44 to be connected to the retaining wall 66 in its second pipe end region 64 without the need to shape the first exhaust gas guide pipe 44 or the retaining wall 46 after positioning the first exhaust gas guide pipe 64 in the retaining wall opening 58. Here, Figure 9 a), Figure 9 b) and Figure 9 c) respectively show different variants of this design with the same working principle, and the retaining interaction between the retaining wall 46 and the first exhaust gas guide pipe 44 is generated by latching.

[0078] Figure 9 a) In combination with Figure 10 it is shown that on the retaining wall 46, four slit-shaped wall interruption regions 70 that are radially inwardly open towards the retaining wall opening 58 are provided in a manner assigned to the retaining wall opening 58. These wall interruption regions also extend in the fixed edge region 60, thereby forming a locking tongue edge region 78 of the fixed edge region 60 in a manner assigned to the locking tongues 76 formed between two circumferentially adjacent wall interruption regions 70 respectively. In each locking tongue edge region in the locking tongue edge region 78, a projection that radially outwardly points with respect to the opening central axis M of the retaining wall opening 58 is formed, and the projection provides a radially inwardly open locking clearance 80.

[0079] On the second pipe end region 64 of the first exhaust gas guide pipe 44, a convex protruding formation that completely surrounds in the circumferential direction around the pipe longitudinal axis R is formed, and the protruding formation forms a locking projection 82 that radially outwardly projects with respect to the pipe longitudinal axis R.

[0080] The first exhaust gas guide pipe 44 provides a locking formation 84 with the locking projection 82, while on the retaining wall 46, a mating locking formation generally denoted by 86 is provided by the section of the locking clearance 80 formed in the locking tongue edge region 78.

[0081] In the construction of the muffler 12, the muffler insert 26 can be surrounded by the circumferential wall 16 in the manner described above. The fixing edge region 60 is arranged with its locking tongue edge region 78 such that the locking tongue edge region 78 extends in a direction away from the associated circumferential wall opening 66. The first exhaust gas guide pipe 44 can then pass through the circumferential wall opening 66 and its second pipe end region 64 can first move in the direction towards the retaining wall 46 until the locking projection 82 reaches a abutment on the end region radially inside the locking tongue 76. When the first exhaust gas guide pipe 44 is further moved into the muffler housing 14, the locking projection 82 carries the locking tongue 76 in the direction of movement, i.e. away from the circumferential wall opening 66, until the following positioning is achieved, in which the first elastically deformed locking tongue 76 springs back and a section of its locking recess 80 locks onto the locking projection 82.

[0082] Then the following state is achieved, in which the first exhaust gas guide pipe 44 is held on the retaining wall 46 in a defined position in the direction of the pipe longitudinal axis R by latching, also in the first exhaust gas guide pipe 44 which has not yet been fixed to the circumferential wall 16 by welding, and is thus held on the muffler 12. For this purpose, there is also no need for a profiling of the first exhaust gas guide pipe 44 or the retaining wall 46 for fixing the first exhaust gas guide pipe 44 to the retaining wall 46.

[0083] Subsequently, the first exhaust gas guide pipe 44 can be fixed to the circumferential wall 16 in the region of its first pipe end region 62 in the manner described above.

[0084] It should be noted that also in this design, the fixing edge region 60 can be arranged on the retaining wall 46 such that in the muffler insert 26 surrounded by the circumferential wall 16, the fixing edge region 60 extends in the direction towards the circumferential wall opening 66. Here, the first exhaust gas guide pipe 44 can again correspond to Figure 3 and Figure 4The manner and method of the design are positioned in the retaining wall opening 58 in the region of the second tube end region 64 in such a way that the locking projection 82 is not yet positioned to engage in the locking recess 80. After the muffler insert 26, in which the first exhaust gas guide tube 44 is already provided, has been surrounded by the circumferential wall 16, the first exhaust gas guide tube 44 can then again move from the inside with its first tube end region 62 first in the direction of the circumferential wall opening 16 and be positioned to engage in said circumferential wall opening. In this process, the locking projection 82 also moves in the direction of the circumferential wall opening 66 and in so doing carries the locking tongue 76 until the locking tongue latches on the locking projection 82 with the section provided thereon of the locking recess 80. Thus, in this design, the locking tongue edge region 78 or the fixing edge 60 also preferably bends on the retaining wall 46 in the following direction, in which the first exhaust gas guide tube 44 moves when the first tube end region 62 moves into the circumferential wall opening 66.

[0085] Figure 9 b) shows a variant in which the locking projection 82 is not constructed in a circumferential manner along the circumferential direction around the tube longitudinal axis R, but has a plurality of locking projection segments 88 succeeding one another in the circumferential direction. Correspondingly, it is also possible to form separate segments of the locking recess 80 in the locking tongue edge region, so that a circumferentially acting latching of the first exhaust gas guide tube 44 on the retaining wall 46 is also achieved. This can be advantageous when the first exhaust gas guide tube 44 does not have a rotationally symmetric design and is to be positioned with respect to the retaining wall 46 in a defined rotational position around the tube longitudinal axis R.

[0086] Another variant is shown in Figure 9 c). In this variant, the locking formation 84 on the first exhaust gas guide tube 44 comprises two raised convex formations or the locking projections 82, 82' provided thereby, which are spaced apart from one another in the direction of the tube longitudinal axis R. A recess is formed between the two locking projections 82, 82', into which the retaining wall tongue 76 provided on the retaining wall 46 can be positioned to engage. Although not mandatory, in this design it is also possible to provide a fixing edge region 60 on the retaining wall 46 that surrounds the retaining wall opening 58 and that has a retaining tongue edge region 78 provided respectively on the retaining tongue 76, so that a planar abutment interaction between the first exhaust gas guide tube 44 and the retaining wall 46 is also achieved in this design.

[0087] In Figure 9 the design shown in c), at least one of the locking projections 82 may also not be provided by a circumferentially surrounding raised convex formation on the first exhaust gas guide tube 44, but may be interrupted in the circumferential direction and provided, for example, in the form of a plurality of segments.

[0088] It should also be noted that the locking forming part 84 can also be provided by a radially inwardly directed, convexly shaped recessed forming part, if necessary in the form of a plurality of successively circumferential sections, which provide a radially outwardly open locking clearance or sections thereof. On the holding wall, a radially inwardly directed convex forming part which cooperates with the locking forming part 86 and which provides a locking projection respectively may be provided in the region of the holding wall tongue, if necessary in the region of the respective edge region 78 of the holding wall tongue. When the first exhaust gas guide pipe 44 moves with respect to the holding wall 46, the convex forming part can be positioned to engage in a locking clearance provided on the second pipe end region 64 of the first exhaust gas guide pipe 44. This design is mainly advantageous when the first exhaust gas guide pipe 44 first moves through the circumferential wall opening 66 in its second pipe end region 64 and then engages in the holding wall opening 58, because then the circumferential wall opening 66 does not need to be so large that the radially outwardly projecting locking projections on the first exhaust gas guide pipe 44 can also be guided through the circumferential wall opening. However, the provision of such a locking clearance on the first exhaust gas guide pipe 44 can lead to a reduction in the flow cross-section of the first exhaust gas guide pipe 44 by the radially inwardly directed convexly shaped convex forming part for providing the locking clearance. Therefore, the provision of the locking forming part 84 by radially outwardly forming the first exhaust gas guide pipe 44 can in principle be regarded as advantageous.

[0089] Finally, it should be noted that the previously described design variants can vary in different aspects. Thus, for example, more or fewer than four of the shown wall interruption regions can be provided for forming the respective holding wall tongues or locking tongues, and the wall interruption regions can, for example, have a greater extension dimension in the circumferential direction, so that, for example, the circumferential extension dimension of the respective wall interruption region can be greater than the circumferential extension dimension of the holding wall tongue or locking tongue respectively formed between two wall interruption regions.

Claims

1. A method for manufacturing an exhaust muffler, the method comprising the following steps: a) providing at least one muffler insert (26) having at least one retaining wall (46) and at least one retaining wall opening (58) in the at least one retaining wall (46); b) providing at least one first exhaust guide pipe (44); c) surrounding the at least one muffler insert (26) with a circumferential wall (16) of a muffler housing (14), and providing a circumferential wall opening (66) in the circumferential wall (16) in a manner assigned to the at least one retaining wall opening (58); d) arranging the at least one first exhaust guide pipe (44) such that a first pipe end region (62) of the at least one first exhaust guide pipe (44) is positioned to be inserted into the circumferential wall opening (66) provided in a manner assigned to the at least one retaining wall opening (58), and a second pipe end region (64) of the at least one first exhaust guide pipe (44) is held in the at least one retaining wall opening (58) by form - fit or snap - fit; e) connecting the at least one first exhaust guide pipe (44) to the circumferential wall (16) by material - fit in the region of the circumferential wall opening (66); Among them, In step a), positioning the at least one first exhaust guide pipe (44) to be inserted into the at least one retaining wall opening (58), characterized in that in step d), the at least one first exhaust guide pipe (44) is moved first from the inside in the direction towards the circumferential wall opening (66) with its first pipe end region (62) until the first pipe end region (62) is positioned to be inserted into the circumferential wall opening (66) and the second pipe end region (64) is held in the at least one retaining wall (46) in a manner inserted into the at least one retaining wall opening (58) by form - fit or snap - fit.

2. The method according to claim 1, characterized in that, In step a), providing the at least one muffler insert (26) such that the at least one retaining wall (46) is connected to intermediate walls (30, 32) in each of its two opposite end regions (48, 50).

3. The method according to claim 1 or 2, characterized in that, In step c), surrounding the at least one muffler insert (26) with the circumferential wall (16) by winding a plate - like circumferential wall blank around the at least one muffler insert (26), or in step c), surrounding the at least one muffler insert (26) by providing a circumferential wall (16) having a circumferentially - closed structure and pushing the at least one muffler insert (26) into the circumferential wall (16) provided with a circumferentially - closed structure.

4. The method according to claim 1 or 2, characterized in that, There is a step f) for fixing end walls (22, 24) to each axial end region (18, 20) of the circumferential wall (16) longitudinally extending in the direction of the housing longitudinal axis (L) by material - fit or / and form - fit before or after implementing step c).

5. The method according to claim 1 or 2, characterized in that The at least one first exhaust gas guiding pipe (44) is connected to the circumferential wall (16) by welding, or / and the at least one first exhaust gas guiding pipe (44) is an inlet pipe.

6. The method according to claim 1 or 2, characterized in that, In the at least one retaining wall (46), a retaining wall opening (58) is provided in a manner assigned to the at least one first exhaust gas guiding pipe (44), and the retaining wall opening (58) is at least partially surrounded by a bent fixing edge region (60) of the at least one retaining wall (46). The at least one first exhaust gas guiding pipe (44) is positioned with its second pipe end region (64) to be fitted into the retaining wall opening (58) and is held in the region of the fixing edge region (60) in the retaining wall opening (58) by a press fit.

7. The method according to claim 6, characterized in that, The fixing edge region (60) is bent in the direction towards the first pipe end region (62) of the at least one first exhaust gas guiding pipe (44), or the fixing edge region (60) is bent in the direction away from the first pipe end region (62) of the at least one first exhaust gas guiding pipe (44).

8. The method according to claim 1 or 2, characterized in that, In the region of the retaining wall opening (58) provided on the at least one retaining wall (46) in a manner assigned to the at least one first exhaust gas guiding pipe (44), a circumferentially completely surrounding abutting contact is provided between the at least one first exhaust gas guiding pipe (44) and the at least one retaining wall (46) for providing a form-locking connection between the at least one first exhaust gas guiding pipe (44) and the at least one retaining wall (46).

9. The method according to claim 1 or 2, characterized in that, In the region of the retaining wall opening (58) provided on the at least one retaining wall (46) in a manner assigned to the at least one first exhaust gas guiding pipe (44), an abutting contact interrupted in at least one circumferential region is provided between the at least one first exhaust gas guiding pipe (44) and the at least one retaining wall (46) for providing a form-locking connection between the at least one first exhaust gas guiding pipe (44) and the at least one retaining wall (46).

10. The method according to claim 9, wherein In the at least one retaining wall (46), in the region of the retaining wall opening (58) provided on the at least one retaining wall (46) in a manner assigned to the at least one first exhaust gas guiding pipe (44), a plurality of wall interruption regions (70) are provided which are spaced apart from each other in the circumferential direction around the retaining wall opening (58) and open towards the retaining wall opening (58).

11. The method according to claim 1 or 2, characterized in that, A locking formation (84) is provided on the second pipe end region of the at least one first exhaust gas guiding pipe (44), and a mating locking formation (86) which is in locking engagement with the locking formation (84) is provided on the at least one retaining wall (46) in a manner assigned to the locking formation (84).

12. The method according to claim 11, characterized in that, The locking formation (84) includes at least one locking projection (82) which projects radially outwards with respect to the pipe longitudinal axis (R) of the at least one first exhaust gas guiding pipe (44).

13. The method according to claim 12, wherein The locking forming part (84) includes at least two locking protrusions (82, 82') successively arranged in the direction of the pipe longitudinal axis (R), or / and the locking forming part (84) includes at least two locking protrusion segments (88) successively arranged in the circumferential direction around the pipe longitudinal axis (R).

14. The method according to claim 12, wherein At least one locking protrusion (82) is provided by a convex protruding forming part of the at least one first exhaust guiding pipe (44).

15. The method according to claim 14, wherein Each locking protrusion (82) is provided by a convex protruding forming part of the at least one first exhaust guiding pipe (44).

16. The method according to claim 11, wherein A retaining wall opening (58) is arranged in the at least one retaining wall (46) in a manner allocated to the at least one first exhaust guiding pipe (44). In the at least one retaining wall (46), there are a plurality of wall interruption regions (70) arranged at a circumferential interval around the retaining wall opening (58) and opening towards the retaining wall opening. A locking tongue (76) of the mating locking forming part (86) is formed between at least two directly successively arranged wall interruption regions (70) in the circumferential direction.

17. The method according to claim 16, wherein The locking forming part (84) includes at least two locking protrusions (82, 82') successively arranged in the direction of the pipe longitudinal axis (R), or / and the locking forming part (84) includes at least two locking protrusion segments (88) successively arranged in the circumferential direction around the pipe longitudinal axis (R), and at least one locking tongue (76) of the mating locking forming part (86) is fitted between two locking protrusions (82, 82') successively arranged in the direction of the pipe longitudinal axis of the locking forming part (84).

18. The method according to claim 17, wherein Each locking tongue (76) of the mating locking forming part (86) is fitted between two locking protrusions (82, 82') successively arranged in the direction of the pipe longitudinal axis of the locking forming part (84).

19. The method according to claim 12, wherein A retaining wall opening (58) is arranged in the at least one retaining wall (46) in a manner allocated to the at least one first exhaust guiding pipe (44). In the at least one retaining wall (46), there are a plurality of wall interruption regions (70) arranged at a circumferential interval around the retaining wall opening (58) and opening towards the retaining wall opening. A locking tongue (76) of the mating locking forming part (86) is formed between at least two directly successively arranged wall interruption regions (70) in the circumferential direction, and a locking clearance (80) for accommodating at least one locking protrusion (82) of the locking forming part (84) is arranged on at least one locking tongue (76).

20. The method according to claim 19, wherein A locking clearance (80) for accommodating at least one locking protrusion (82) of the locking forming part (84) is arranged on each locking tongue (76).

21. The method according to claim 16, characterized in that, A bent locking tongue edge region (78) is arranged on the at least one locking tongue (76) on the at least one retaining wall (46).

22. The method according to claim 21, wherein A bent locking tongue edge region (78) is arranged in each locking tongue (76).

23. The method according to claim 17, wherein On the at least one retaining wall (46), in at least one locking tongue (76), there is provided a bent locking tongue edge region (78), and at least one locking tongue edge region (78) is engaged between two successive locking protrusions (82, 82') of the locking formation (84) in the direction of the pipe longitudinal axis (R).

24. The method according to claim 23, wherein Each locking tongue edge region (78) is engaged between two successive locking protrusions (82, 82') of the locking formation (84) in the direction of the pipe longitudinal axis (R).

25. The method according to claim 19, characterized in that, On the at least one retaining wall (46), in at least one locking tongue (76), there is provided a bent locking tongue edge region (78), and in at least one locking tongue edge region (78), there is provided at least one locking recess (80).

26. The method according to claim 25, wherein In each locking tongue edge region (78), there is provided at least one locking recess (80).

27. The method according to claim 4, wherein The muffler insert (26) includes at least two intermediate walls (28, 30, 32, 34) that are orthogonally arranged relative to the housing longitudinal axis (L) and supported on the circumferential wall (16), and the at least one retaining wall (46) is fixed to one of the intermediate walls (28, 30, 32, 34) in each of its two opposite end regions (48, 50).

28. The method according to claim 27, wherein The muffler insert (26) includes at least one second exhaust guide pipe (52, 54), and in an intermediate wall (30, 32) connected to the at least one retaining wall (46) in a manner allocated to the at least one second exhaust guide pipe (52, 54), there is provided an intermediate wall opening, and in one of the end walls (22, 24), there is provided an end wall opening. The at least one second exhaust guide pipe (52, 54) is positioned to be engaged in the intermediate wall opening and the end wall opening and is fixed by material locking on the end wall (22, 24) having the end wall opening in the region of the end wall opening and / or on the intermediate wall having the intermediate wall opening in the region of the at least one intermediate wall opening.

29. An exhaust device for an internal combustion engine, the exhaust device including at least one muffler (12) manufactured by the method according to any one of claims 1 to 28.

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