WO2020114637A1

WO2020114637A1 - Silencer and method for producing a silencer

Info

Publication number: WO2020114637A1
Application number: PCT/EP2019/072905
Authority: WO
Inventors: Tobias Bretschi
Original assignee: Apworks Gmbh
Priority date: 2018-12-06
Filing date: 2019-08-28
Publication date: 2020-06-11
Also published as: DE102018221095A1

Abstract

The present invention relates to a silencer (1) having an integrally formed base body (2), which defines a longitudinal axis (L), in which a channel (3), extending along the longitudinal axis (L) between an entry opening (31) and an exit opening (32), and a plurality of expansion chambers (4), arranged in succession along the longitudinal axis (L), are formed. According to the invention, the expansion chambers (4) each have an entry section (41) extending at an angle to the longitudinal axis (L) and a damping section (42) defining a circular cavity (43), wherein the cavity (43) has an opening (44) facing the longitudinal axis (L), which opening is delimited in relation to the longitudinal axis (L) by an outer end region (41B) of the entry section (41), which outer end region is situated facing away from the longitudinal axis (L). The invention furthermore relates to a use of the silencer (1) and to a method for producing the silencer (1).

Description

Muffler and method of making a muffler

The present invention relates to a muffler, a use of a muffler with a firearm, and a method for manufacturing a muffler.

Typically, when gases emerge from orifices into the environment at high speed, this leads to an uncontrolled expansion of the gases, which results in noise. The noise level is additionally increased if the gas flows at supersonic speed. Such situations can arise, for example, at exhaust gas outlets of piston engines or turbines or in the muzzle region of firearms.

Silencers are often used to reduce noise. A silencer for a firearm with a monolithic main body extending along a longitudinal axis and having a plurality of expansion chambers arranged one behind the other along the longitudinal axis is described, for example, in US 2014/0262605 A1. The

DE 10 2015 002 710 Al describes a similar silencer

monolithic main body, wherein the expansion chambers are each open in the opposite direction to allow multiple flows through the same expansion chamber. It is an object of the present invention to provide a silencer which has a good damping effect, preferably with a low weight

This object is achieved in each case by the subject matter of the independent claims.

According to a first aspect of the invention, a silencer is provided. The muffler comprises an integral longitudinal axis

defining base body, in which a channel extending along the longitudinal axis between an inlet opening and an outlet opening and a plurality of channels arranged one after the other along the longitudinal axis

Expansion chambers are formed. The expansion chambers each have an inlet section that is angled to the longitudinal axis and a damping section that defines a circular cavity, the cavity having an opening facing the longitudinal axis, which is delimited with respect to the longitudinal axis by an outer end region of the inlet section that is remote from the longitudinal axis

According to a second aspect of the invention, the

Silencer according to the first aspect of the invention as a silencer for a

Firearm.

According to a third aspect of the invention, a method for producing a muffler according to the first aspect of the invention is provided, the base body being built up in layers by an additive manufacturing process or a 3-D printing process. One idea on which the invention is based is to design the expansion chambers of a muffler in a one-piece or monolithic base body as circular or round damping chambers, which have an opening facing a central longitudinal channel. The damping chambers or damping sections are thus designed as closed cavities which are connected to the channel in a fluidly conductive manner only through the opening. In the context of the present disclosure, “circular” is also understood to mean oval cross-sectional shapes, in particular also those which are composed of curved sections and straight sections. The opening of the cavity is delimited by an outer entry section, in particular on a side facing away from the inlet opening of the channel. which, in the manner of a guide plate, opens out obliquely with an inner end region from the longitudinal channel or extends at an angle to the longitudinal axis of the channel in order to supply gas to the cavity via the opening spaced apart from the longitudinal channel and are connected to the channel in a fluidly conductive manner via the inlet section and the opening of the cavity which is inward with respect to the radial direction.

One of the advantages of the muffler according to the invention is that due to the circular design of the cavity of the damping section, a gas stream supplied to the cavity through the opening through the inlet section flows several times through the cavity.This means that the volume of the damping section is used very efficiently and large pressure reductions per damping section can be achieved will. The circular design as a closed cavity is particularly advantageous in the supersonic area, since there are a large number of inside the cavity

Expansion waves or bumps occur, making them extremely efficient Pressure reduction takes place The formation of shock and expansion waves is further promoted by the angular orientation of the inlet section. Due to the large pressure drop per expansion chamber, the number of

Expansion chambers and thereby the weight of the silencer can be reduced.

When using the muffler according to the second aspect of the invention, the above structure is particularly advantageous since the handling of the muffler is due to the low weight and the compact structure of the muffler

Firearm on which the silencer is used is facilitated.

The idea of the method according to the third aspect of the invention is to produce the base body by means of an additive or generative manufacturing method or a 3-D printing method. 3D printing methods in the sense of the present disclosure include all generative or additive

Manufacturing processes in which, based on geometric models, objects of a predefined shape are produced from formless materials such as liquids and powders or shape-neutral semi-finished products such as strip or wire-shaped material using chemical and / or physical processes in a special generative manufacturing system. 3D printing processes in the sense of the present application use additive processes in which the starting material is built up sequentially in layers in predetermined forms. This ensures excellent design freedom.

In particular, the base body can be manufactured particularly easily in the present case. Advantageous refinements and developments result from the subclaims which refer back to the independent claims in conjunction with the description.

According to one embodiment of the muffler, it is provided that the opening of the cavity with respect to the longitudinal axis is additionally limited by a wall extension of the damping section that extends along the longitudinal axis, the wall extension with respect to a radial direction that extends perpendicular to the longitudinal axis within the outer end region of the entry section, and wherein the outer end region of the

Inlet section extends planarly With respect to the longitudinal axis, the wall extension thus delimits a side of the opening of the cavity facing the inlet opening of the channel. Furthermore, the wall extension limits the cavity with respect to the radial direction inwards or towards the longitudinal axis. The outer end region of the inlet section, which adjoins the opening, extends flat or planar, that is to say the one facing the wall extension

The surface is flat and not curved along the longitudinal axis. A tangent to the outer end area thus forms a constant angle with the longitudinal axis. Due to the overlap of the wall extension with the flat or planar outer end region of the inlet section, a gas flow circulating in the cavity is guided from the wall extension to the outer end region of the inlet section. Through its planar extension

reliable reintroduction of the

Gas flow into the cavity is facilitated, since this reduces the risk of the shock waves being reflected out of the cavity.

Optionally, a surface of the wall extension facing the cavity, which is in relation to the radial direction within the outer end region of the Entry section is located, also flat or planar, whereby the recirculation of the gas flow in the cavity is further improved.

According to a further embodiment, the outer end region of the

Entry section tangentially into the damping section, in particular a curved region of the damping section.

According to a further embodiment of the silencer, it is provided that the inlet section extends at an angle such that an inner end region of the inlet section facing the longitudinal axis is at a smaller distance from the inlet opening of the duct than the outer end region of the inlet section. The inlet opening of the channel is for supplying one

Gas flow, e.g. of explosion gases in firearms or exhaust gases in internal combustion engines such as piston engines or turbines. A distance between the longitudinal axis and the inlet section thus increases from the inlet opening of the channel to the opposite outlet opening, so that the inlet section can conduct a gas flowing from the inlet to the outlet opening from the channel into the radially outer damping sections. In the case of supersonic flows, this offers the advantage that shock waves can be formed along the inlet section, which

Damping effect further improved.

According to a further embodiment, a volume, which is defined by the cavity of the respective damping section, decreases along the longitudinal axis. Accordingly, the individual cavities become the along the longitudinal axis

The opening of the channel is getting smaller. Surprisingly, the damping effect is not or only slightly reduced. The weight of the silencer is further reduced According to a further embodiment, the base body in the region of the damping sections on surfaces which define the respective cavity has a mean roughness value R _a in a range between 1 and 50. The

Roughness values are given here in pm. It has been shown in the range indicated that the damping effect is very good. A range of the average roughness value R _a between 5 and 20 has proven to be particularly advantageous. This range includes roughness values which are higher than those of the silencers' surfaces stiffened by conventional machining processes. This significantly improves the sound absorption effect.

According to a further embodiment of the muffler, it is provided that the cavity of the damping section contains a porous filling formed in one piece with the base body. The porous filling can in particular be realized as a preferably regular grid structure composed of a plurality of rod-shaped elements or as an open-pore, irregular foam structure. The filling and the base body are monolithic, that is, they are formed as one part. The cavity can be filled as a whole by the filling. Alternatively, it is also conceivable to only fill partial areas of the cavity with the porous structure of the filling, for example by applying the filling with a predetermined thickness to walls which define the cavity. In general, the cavity is thus at least partially filled by the filling. The high internal surface area of the porous filling improves heat transfer from the gas flow to the base body. Due to the high inner surface, the gas flow is also slowed down by friction or numerous impact effects and the kinetic energy of the flow is thereby converted into thermal energy large inner surface of the filling can be removed particularly efficiently. This is also accompanied by a total pressure loss.

According to a further embodiment of the muffler, it is provided that the base body is formed at least in regions by or with walls which have a porous inner region. Accordingly, individual or all walls of the base body can have a sandwich-like structure with respect to their cross-sectional thickness. In this case, a porous, for example foam or lattice-like inner area is arranged in relation to the cross-sectional thickness of the wall between outer cover areas, the cover areas being solid, that is to say made of solid material. As a result, the weight of the muffler is further reduced, the muffling effect advantageously not being adversely affected.

According to a further embodiment of the base body, it additionally forms a plenum from which the inlet opening of the channel opens, the plenum having a feed opening opposite the inlet opening of the channel.The plenum is thus arranged in relation to the longitudinal axis in front of the inlet opening of the channel and points in With respect to the radial direction, the inner diameter is larger than the channel. A gas entering the plenum through the supply opening thus already expands in the plenum before it is fed to the channel and from there to the individual expansion chambers.

According to a further embodiment, the base body has one in the area of the inlet opening of the channel, optionally in the area of the plenum

Connection section for connecting the base body to a tube, in particular to a barrel of a firearm. The connection section or the

Connection structure can be formed, for example, by a thread. According to a further embodiment of the silencer, the base body is made of a metal alloy. For example, an aluminum alloy, for example an aluminum-magnesium-scandium alloy, which is sold under the "Sealmalioy" brand, a titanium alloy, a steel alloy or a nickel base can be used as the metal alloy Alloy are used.

According to one embodiment, the base body is made of a plastic material. In particular, the base body can be made of a fiber-reinforced material

Plastic material such as printed CFRP material.

According to one embodiment of the method, the base body is built up in layers along the longitudinal axis, e.g. starting with the area of

Entrance opening

According to a further embodiment of the method, the additive manufacturing method comprises a selective laser melting method

Electron beam melting process or a build-up welding process. Selective laser melting processes are referred to, for example, as the SLM process, where “SLM” stands for the English expression “selectlve laser melting”. In the SLM process, a laser beam is usually used in the form of a powder

The raw material is melted to form the desired structure.

Electron beam melting processes can also be referred to as EBM processes, where “EBM” stands for the English expression “electron beam melting”. In this case, an electron beam is used to produce a generally powdery one

The raw material is melted to form the desired structure. During solid build-up welding, a solid starting material is melted and in

molten state applied in layers to form the structure. In the context of the present disclosure, “one-piece”, “one-piece”, “integral”, “monolithic” or “in one piece” components are generally understood to mean that these components as a single, one

Part forming the material unit and in particular are produced as such, e.g. by means of a 3-D printing process, one of which cannot be detached from the other without removing the material cohesion from the other

With regard to directions and axes, in particular directions and axes, which relate to the course of physical structures, a course of an axis, a direction or a structure “along” another axis, direction or structure is understood here to mean that these, in particular the tangents resulting in a respective location of the structures each run at an angle of less than 45 degrees, preferably less than 30 degrees and particularly preferably parallel to one another.

With regard to directions and axes, in particular to directions and axes, which relate to the course of physical structures, a course of an axis, a direction or a structure “transversely” to another axis, direction or structure is understood here to mean that these, in particular, the tangents resulting in a respective location of the structures each run at an angle of greater than or equal to 45 degrees, preferably greater than or equal to 60 degrees and particularly preferably perpendicular to one another.

The invention is described below with reference to the figures of FIG

Drawings explained From the figures show: Figure 1 is a schematic sectional view of a muffler according to an embodiment of the present invention.

FIG. 2 is an enlarged, broken sectional view of the one in FIG. 1

Muffler shown in the area of expansion chambers of the muffler;

Fig. 3 is a detailed view of the in Fig. 2 by the letter Z

marked area;

Fig. 4 is an enlarged, broken sectional view of a

Silencer according to a further exemplary embodiment of the present invention in the area of expansion chambers of the silencer;

Fig. 5 is a schematic view of a firearm with a

Silencer according to an embodiment of the

present invention; and FIG. 6 shows a schematic illustration of a step of a method for producing a silencer according to an exemplary embodiment of the present invention. In the figures, the same reference numerals designate identical or functionally identical components, unless stated otherwise.

1 shows an example and schematically a sectional view of a silencer 1. The silencer 1 has a base body 2. As an example in Fig. 1 shown, the base body 2 is realized as an elongated, one-piece or monolithic body, which defines a longitudinal axis L. The base body 2 can in particular have an approximately cylindrical shape, as is shown schematically in FIG. 1. The base body 2 can in particular consist of a

Metal material, e.g. made of an aluminum alloy, one

Titanium alloy, a steel alloy or a nickel-based alloy.

As can be seen in FIG. 1, the base body 2 has a channel 3, a multiplicity of expansion chambers 4, an optional plenum 6 and an optional one

Connection section 62 or the base body 2 forms these structures.

As shown in FIG. 1, the channel 3 extends along, preferably coaxially to the longitudinal axis L. The channel 3 can, for example, be cylindrical

Have cross-section. The channel 3 extends between an inlet opening 31, which is provided for the supply of a gas flow into the channel 3, and an outlet opening 32, which is opposite the inlet opening 31 with respect to the longitudinal axis L and which is used to discharge the gas flow from the channel 3 in the environment is provided in Figs. 1 and 2, an intended flow direction G of a gas flow from the inlet to the outlet opening 31, 32 of the channel 3 is symbolically represented by an arrow.

As further shown in FIG. 1, the base body 2 has a multiplicity of

Expansion chambers 4. As exemplified in Fig. 1, the

Expansion chambers 4 are arranged one after the other or one behind the other along the longitudinal axis L and extend around or enclose the longitudinal axis L. With respect to a radial direction R, which is perpendicular to the

Longitudinal axis L extends, the expansion chambers 4 connect to the channel 3. The expansion chambers 4 are optionally rotationally symmetrical with respect to the Longitudinal axis L formed. Furthermore, the expansion chambers 4 optionally extend coaxially to the longitudinal axis L.

FIG. 2 shows, by way of example and schematically, a partial sectional view of two expansion chambers 4 that follow one another along the longitudinal axis L. As shown schematically in FIG. 2, each expansion chamber 4 has an inlet section 41 and a damping section 42. The inlet section 41 and the damping section 42 are each formed by walls 20 of the base body 2.

As shown schematically in FIG. 2, the entry section 41

in particular as a plate-shaped structure in cross-section, which is inclined at an angle a relative to the longitudinal axis 1 as in FIG. 2

is shown schematically, the inlet section 41 has a first surface 41a facing the inlet opening 31 of the channel 3. This is flat or planar, at least in sections or areas. 2 shows by way of example that the first surface 41a is generally planar, that is to say that the first surface 41a is inclined at a constant angle a relative to the longitudinal axis L. As further shown in FIG. 2, the entry section 41 has an end region 41A which is inner with respect to the radial direction R and faces the longitudinal axis L and an end region 41B which is outer with respect to the radial direction R and which extends from the longitudinal axis L. is facing away

Optionally, the first surface 41a of the entry portion 41 is planar at least in the outer end region 41B. Since the expansion chambers 4 around the

Extending longitudinal axis L defines the first surface 41a of the

Entry section 41, if it extends planar as shown by way of example in FIG. 2, a cone extending around the longitudinal axis L. The angle a can in particular be measured between the first surface 41a of the inlet section 41 facing the inlet opening 31 of the channel 3 and the longitudinal axis L. The angle a is preferably in a range between 25 degrees and 70 degrees, particularly preferably between 30 degrees and 60 degrees. In Fig.

2, the angle a is 45 degrees, for example. As can be seen in particular in FIG. 1, the entry section 41 extends at an angle such that the inner end region 41A of the entry section 41 has a smaller distance along the longitudinal axis L to the entry opening 31 of the channel 3 than the outer end region 41B of the entry section 41. Accordingly, the radial distance of the first surface 41a of the inlet section 41 from the longitudinal axis L increases in a direction from the inlet opening 31 of the channel 3 to the outlet opening 32 of the channel 3.

As shown schematically in FIG. 2, the damping section 42 of a respective expansion chamber 4 is formed by a curved wall area of the base body 2 and defines a circular cavity 43. The curved wall area has an inner surface 43a that defines the circular cross-sectional shape of the cavity 43. 2 is the circular one

Cross-sectional shape of the cavity 43 is realized, for example, as an oval shape with curved sections 43C and straight sections 435. The wall area of the base body 2, which defines the damping section 42, can have, for example, a mean roughness value Ra in a range between 1 and 50, preferably between 5 and 20, on the surface 43a which defines the cavity 43.

As is also shown schematically in FIG. 2, the cavity 43 has an opening 44, which is located in relation to the radial direction R facing the longitudinal axis L. Apart from this opening 44, the cavity 43 is closed or forms a closed volume. The opening 44 is in relation to the Longitudinal axis L delimited on the side facing away from the inlet opening 31 of the channel 3 by the outer end region 41B of the inlet section 41 and on the side facing the inlet opening 31 of the channel 3 by a wall extension 42A of the damping section 42. The wall extension 42A of the damping section 42 and the outer end region 41B of the entry section 41 thus generally define a gap or slot enclosing the longitudinal axis L. One from the inlet opening 31 of the channel 3 in the direction of

The outlet opening 32 of the channel 3 flowing gas flow is thus directed from the angled inlet section 41 to the opening 44 of the cavity 43 and fed through the opening 44 to the cavity 43, as symbolically represented in FIG. 2 by the arrow A. The circular design of the cavity 43 forms a circulating flow within the cavity 43, which flows through the cavity 43 several times, as symbolically represented by the arrow A in FIG. 2.

As is further illustrated by way of example in FIG. 2, the wall extension 42A of the damping section 42 can extend in particular along the longitudinal axis L. Preferably, the wall extension 42A has one of the

Surface facing away from the longitudinal axis L or facing the interior of the cavity 43, which is flat or forms a straight section 43S of the circular cross section. This facilitates the recirculation of the flow within the cavity 43, especially in the supersonic area. Optionally, the wall extension 42A is located with respect to the radial direction R within the outer end region 41B of the entry section 41. 2 is the level of the surface of the

Wall extension 42A with respect to the radial direction R through a

Dashed line r42 shown. As can be seen in FIG. 2, the outer end region 41B of the entry section 41, indicated by a curly bracket in FIG. 2, extends beyond this level with respect to the radial direction R. When the outer end portion 41B of the entrance portion 41 is flat or is planar, as shown by way of example in FIG. 2, this advantageously leads to a reliable flow deflection of one of these

Wall extension 42A towards the outer end portion 41B of the

Entry section 41 flowing gas flow into the cavity 43

In particular in the supersonic range, circumferential shock waves propagate into the cavity 43, so that the volume of the cavity 43 can be used to an improved extent for pressure reduction and thus for sound absorption.

2 shows two expansion chambers 4 arranged one behind the other or adjacent to one another along the longitudinal axis L. As can be seen in FIG. 2, the cavities 43 of the damping sections 42 can have a common partition wall 25 with respect to the longitudinal axis L. FIG. 2 also shows an example that the cavities 43 each have the same volume. Alternatively, it is conceivable that the volume, which is defined by the cavity 43 of the respective damping section 42, decreases along the longitudinal axis L. For example, a first group of cavities 43 can have a first volume and a second group of cavities 43 can have a second volume that is smaller than the first volume, the first group of cavities 43 being located in the region of the inlet opening 31 of the channel 3 and the second group of cavities 43 follows the first group of cavities 43 and is closer to the

Exit opening 32 of the channel is located as the first group. Furthermore, the volume of the cavities 43 can also continuously decrease or decrease from the inlet opening 31 of the channel 3 to the outlet opening 32 of the channel 3.

3 shows an example of a wall 20 of the base body 2 in an enlarged sectional view. As shown by way of example in FIG. 3, a wall 20 of the base body 2 can have a sandwich-like cross-section with outer cross sections Cover layers 21, 22 and an inner region 23 located in relation to the cross-sectional thickness t20 between the cover layers 21, 22. As shown schematically in FIG. 3, the inner region 23 has a porous structure, which can be designed, for example, as a grid composed of rod elements or as a foam-like cell structure. The cover layers 21, 22, however, are designed as a solid material. The cross-sectional thickness t20 of a wall 20 can be, for example, in a range between 0.2 mm and 3.0 mm, regardless of whether it has a porous inner region 23

is formed or not. The thickness of the optional cover layers 21, 22 can be, for example, in a range between 0.2 mm and 1.0 mm. In general, individual or all of the walls 20, 25 of the base body 2 can be formed with the optional porous inner region 23.

FIG. 4 schematically shows a region of a base body 2 in the view in FIG. 2. In contrast to the base body 2 shown in FIG. 2, the base body 2 shown in FIG

4 basic body 2 shown as an example, the cavities 43 of the damping sections 42 are each filled with an optional filling 5. Of course, it is also conceivable to provide only one or a few of the cavities 43 with the filling 5. The optional filling 5 is formed in one piece with the base body 2, preferably from the same material. As shown by way of example in FIG. 4, the filling 5 optionally completely fills the cavity 43 and ends in the region of the opening 44. Alternatively, it can also be provided that the filling 5 fills only part of the cavity 43. The filling 5 can in particular be made of rod elements

composite lattice or as a foam-like, open-cell structure. This porous structure of the filling 5 promotes the conversion of kinetic energy of the gas flow into heat. The dissipation of this heat to the walls 20 of the base body 2 is simultaneously improved due to the high inner surface of the porous filling. As already mentioned and exemplified in FIG. 1, the base body 2 forms an optional plenum 6. The plenum 6 can, in particular, be designed as a cylindrical cavity enclosing the longitudinal axis L, as is shown by way of example in FIG. 1 6 opens out As is further shown in FIG. 1, the plenum 6 has an inlet opening 61 opposite the inlet opening 31 of the channel 3, which is arranged along the longitudinal axis L at a distance from the inlet opening 31 of the channel 3. The inlet opening 61 serves to supply gas . 1 also symbolically shows that the base body 2 in the region of the inlet opening 31 of the channel 3 has or forms a connection section 62 for connecting the base body 2 to a pipe or a line

Connection section 62 can be designed, for example, as a thread. In FIG. 1 it is shown purely by way of example that the connection section 62 as one

Internal thread of the feed opening 61 of the plenum 6 is formed

Fig. 5 shows an example of a firearm 100 in the form of a rifle with a barrel 110. The silencer 1 is arranged in the region of a muzzle of the barrel 110 and can in particular be fastened to the barrel 110, e.g. via the optional connection section 62. The silencer 1 is used in FIG

Damping a muzzle blast, which occurs as a result of a gas flow that arises from the explosion of a propellant to accelerate a projectile. This gas flow is in the manner described above through the inlet portions 41 of the expansion chambers 4 in the

Damping sections 42 of the expansion chambers 4 passed to there

expand. 6 is an example and schematically shows a method for producing the

Silencer 1 presented. Here, the base body 2 of the silencer 2 is produced or built up in layers by an additive manufacturing process.

6 shows schematically and by way of example a 3D printing device 200. For the additive manufacturing of the base body 2, modeling material M is fed to the 3D printing device 200, as is shown schematically in FIG. 6. For this purpose, the modeling material M can be in powder form, for example.

Basically, the present invention provides a variety of options for liquefying the modeling material M, at which heat is generated locally

stored modeling material M can be initiated. Especially that

Use of lasers and / or particle beams, e.g. Electron beams is advantageous because heat can be generated in a very targeted and controlled manner. The additive manufacturing process can thus be selected from the group, for example

Laser sintering, selective laser melting, selective electron beam sintering and selective electron beam melting or the like can be selected.

In principle, however, any additive method can be used, such as cladding.

In the following, the method for producing the silencer 1 will be explained by way of example in connection with selective laser melting (SLM), in which the modeling material M is applied in powder form to a work platform 201 of the 3D printing device and is specifically liquefied by local laser irradiation with a laser beam 202 , resulting in a coherent base body 2 after cooling. An energy source in the form of a laser 203, for example an NdiYAG laser, sends a laser beam 202 selectively to a specific part of one

Powder surface of the powdery modeling material M, which rests in a working chamber 204 on the work platform 201. For this purpose, an optical deflection device or a scanner module, such as a movable or

tiltable mirror 205 may be provided which, depending on its tilted position, the laser beam 202 onto a specific part of the powder surface of the

Modeling material M deflects The modeling material M is heated at the point of impact of the laser beam 202, so that the powder particles are melted locally and form an aggiomerate when cooled. Depending on a ready-made digital model of the base body 2, which

if necessary, the laser beam 202 rasterizes the

Powder surface. After the selective melting and local agglomeration of the powder particles in the surface layer of the modeling material M, excess, non-agglomerated modeling material M can be separated out. The work platform 201 is then lowered by means of a lowering piston 206 (see arrow L200 in FIG. 6) and new modeling material M is transferred from a reservoir into the working chamber 204 with the aid of a powder supply 207 or another suitable device. This creates an iterative generative build-up process In layers, a three-dimensional, sintered or “printed” base body 2 made of agglomerated modeling material M. The surrounding powdery modeling material M can serve to support the part of the base body 2 built up to that point. The base body 2 in is created by the continuous downward movement of the work platform 201

layered model generation. 6 shows that the base body 2 is built up in layers along the longitudinal axis L, starting with the optional plenum 6. Although the present invention has been explained by way of example using exemplary embodiments, it is not restricted to these, but can be modified in a variety of ways. In particular, combinations of the above exemplary embodiments are also conceivable.

REFERENCE SIGN LIST

1 silencer

2 base bodies

3 channel

4 expansion chambers

5 filling

6 plenary

20 walls

21, 22 outer layers

23 interior

25 partition

23 interior

31 inlet opening

32 outlet opening

41 entry section

41A outer end portion of the entrance portion 41B inner end portion of the entrance portion

42 damping section

42A wall extension

43 cavity

43a surface

43 C curved sections

43S straight sections

44 Opening the cavity

61 Plenary feed opening

62 connection section

100 firearms 110 run

200 3D printing device

201 work form

202 laser beam

203 lasers

204 working chamber

205 mirrors

206 lowering piston

207 powder feed

oc angle

A arrow

A200 arrow

G flow direction

L longitudinal axis

M modeling material

R radial direction

r42 dashed line or level of the wall extension t20 cross-sectional thickness of the wall

Claims

EXPECTATIONS

1. Muffler (1) with a one-piece, a longitudinal axis (L) defining base body (2), in which a along the longitudinal axis (L) between an inlet opening (31) and an outlet opening (32) extending channel (3) and a plurality of expansion chambers (4) arranged one after the other along the longitudinal axis (L) are formed;

wherein the expansion chambers (4) each have an inlet section (41) angled to the longitudinal axis (L) and a damping section (42) defining a circular cavity (43); wherein the cavity (43) has an opening (44) facing the longitudinal axis (L) which, with respect to the longitudinal axis (L), extends through an outer end region (41B) of the

Entry section (41) is limited

2 muffler (1) according to claim 1, wherein the opening (44) of the cavity (43) with respect to the longitudinal axis (L) additionally from a along the longitudinal axis (L) extending wall extension (42A) of

Damping section (42) is limited, wherein the wall extension (42A) with respect to a radial direction (R) extending perpendicular to the longitudinal axis (L) is located within the outer end region (41B) of the inlet section (41), and wherein the outer End region (41B) of the

Entry section (41) extends planar.

3. Muffler (1) according to claim 1 or 2, wherein the inlet section (41) extends angled such that an inner end region (41A) of the el nittsa bsch nitts (41) facing the longitudinal axis (L) a smaller distance from the Entry opening (31) of the channel (3) has as the outer end region (41B) of the entry section (41).

4. Silencer (1) according to one of the preceding claims, wherein a volume, which is defined by the cavity (43) of the respective damping section (42), decreases along the longitudinal axis (L).

5. Silencer (1) according to one of the preceding claims, wherein the base body (2) in the area of the attenuation sections (42) on surfaces (43a) which the respective cavity (43) define a roughness _Ra in a range between 1 and 50 , preferably between 5 and 20.

6. Silencer (1) according to one of the preceding claims, wherein the cavity (43) of the damping section (42) is integral with the

Contains basic body (2) trained porous filling (5).

7. Silencer (1) according to one of the preceding claims, wherein the base body (2) is formed at least in regions by walls (20) which have a porous inner region (23).

8. silencer (1) according to any one of the preceding claims, wherein the base body (2) additionally forms a plenum (6), from which the

Entry opening (31) of the channel (3) opens out, the plenum (6) having an inlet opening (61) opposite the entry opening (31) of the channel (3)

9. Muffler (1) according to one of the preceding claims, wherein the base body (2) in the region of the injection opening (31) of the channel (3)

Connection section (62) for connecting the base body (2) to a tube, in particular to a barrel (110) of a firearm (100).

10. Silencer (1) according to one of the preceding claims, wherein the base body (2) made of a metal alloy, in particular

Aluminum alloy, a titanium alloy, a steel alloy or a nickel-based alloy, or is made of a plastic material, in particular a fiber-reinforced plastic material.

11. Use of a silencer (1) according to one of the preceding claims as a silencer for a firearm (100).

12. A method for producing a muffler (1) according to one of the preceding claims, wherein the base body (2) is built up in layers by an additive manufacturing method.

13. The method according to claim 12, wherein the base body (2) along the

Longitudinal axis (L) is built up in layers.

14. The method according to any one of claims 12 and 13, wherein the additive

Manufacturing process a selective laser melting process, a

Electron beam melting process or a cladding process includes.