EP3847355B1 - Cylinder head for an internal combustion engine and method for the production thereof - Google Patents

Description

The invention relates to a cylinder head for covering a combustion chamber of an internal combustion engine and a method for manufacturing a cylinder head.

the DE 100 39 790 A1 discloses a cylinder head of an internal combustion engine with exhaust ports arranged therein, which have an inner port frame formed from at least one sheet metal layer.

the DE 10 2005 025 731 A1 discloses an exhaust gas duct for an internal combustion engine, the exhaust gas duct containing at least one exhaust gas duct running in the cylinder head of the internal combustion engine and an exhaust gas system adjoining the cylinder head on the outlet side. An air-gap insulated element is arranged in the exhaust gas duct at least over the area of the exhaust gas outlet. The member is a thin-walled sleeve-like insert secured within the exhaust duct and having means by which the insert is radially spaced from the duct wall. Alternatively, the element can be formed by an exhaust gas pipe of the exhaust system that protrudes freely into the exhaust gas duct, with the exhaust gas duct being widened in the area into which the exhaust gas pipe protrudes, forming a stepped shoulder, and the element covering the shoulder edge radially outwards circumferentially.

Although the known devices can have a heat-insulating effect with respect to the exhaust gas duct, they are complicated to manufacture and/or assemble.

The object of the invention is to create an alternative and/or improved cylinder head for an internal combustion engine.

The object is achieved by the features of independent claim 1. Advantageous developments are specified in the dependent claims and the description.

The invention provides a cylinder head (e.g. single-cylinder cylinder head or multi-cylinder cylinder head) for covering a combustion chamber of an internal combustion engine. The cylinder head has a fluid duct for supplying a fluid (e.g. intake air, charge air and/or air-fuel mixture) to the combustion chamber or for discharging a fluid (e.g. exhaust gas or compressed air) from the combustion chamber. The cylinder head has a cooling channel for a cooling fluid (e.g. water, water-coolant mixture or oil) for cooling the cylinder head. The cylinder head has at least one material recess Heat insulation formed in a main body of the cylinder head (e.g. by casting the cylinder head). The at least one material recess is arranged between the fluid duct and the cooling duct. The at least one material recess is arranged by the main body separated from the fluid conducting channel (e.g. by a support area of the main body for supporting the fluid conducting channel in the main body).

The at least one material recess can easily, for. e.g. directly during the primary forming (e.g. casting) of the main body of the cylinder head and/or subsequently thereto. Depending on the design of the fluid duct, the material recess can offer different advantages. The advantages are based in each case on a (partial) thermal decoupling of the fluid-guiding channel and the cooling channel through the at least one heat-insulating material recess. For example, in the case in which the exhaust gas is routed through the fluid duct, there can be a significantly lower heat input from the hot exhaust gas into the cooling fluid. This leads to a reduction in the cooling requirement, which enables an improved design of the cooling system. This makes it possible, for example, to reduce fuel consumption by the internal combustion engine, for example also by saving energy when driving a coolant pump. In addition, the thermal decoupling means that the hot exhaust gas cools down less in the fluid duct. As a result, more exhaust gas enthalpy is available for an exhaust gas turbocharger and/or an exhaust gas aftertreatment device that may be arranged downstream. This enables improved design and efficiency of these components and a reduction in fuel consumption.

The term "material cutout" used here can be understood in such a way that it refers to a material cutout deliberately provided by a corresponding production step and not to cavities or the like that occur unintentionally during casting or printing.

Advantageously, the fluid duct without an insert, z. B. a tube insert formed.

For example, the at least one material recess can be radially spaced through the main body from a channel wall or an outer contour of the fluid conducting channel.

In one embodiment, the at least one material recess is produced by primary shaping, reshaping and/or cutting.

In another embodiment, the main body is cast or printed (e.g., using a 3D printer).

In a further embodiment, the at least one material recess is formed during the primary shaping, preferably during casting and/or printing (e.g. using a 3D printer), of the main body or subsequently thereto, preferably by a separating manufacturing process (e.g. drilling, milling or similar).

In one embodiment, the fluid duct is designed as an exhaust gas duct, an intake duct (eg air intake duct or air-fuel mixture intake duct) or a compressed air extraction duct. For example, in the case of the intake duct, the intake air, which should preferably have a temperature between 30°C and 50°C, can be heated less by the cooling fluid, which typically has a temperature above 90°C. This can, for example, enable an improved design of intercoolers etc.

It is possible that several fluid ducts (e.g. two exhaust ducts and/or two intake ducts) are included in the cylinder head and the at least one material recess for thermal insulation is arranged between the several fluid ducts on the one hand and the cooling duct on the other.

In a further exemplary embodiment, the cylinder head has a valve, preferably a poppet valve, which is arranged for sealing off the fluid duct on the combustion chamber side.

In one embodiment, the at least one material cutout is designed to reduce, preferably significantly, heat transfer between the cooling channel and the fluid conducting channel.

In a further exemplary embodiment, the at least one material cutout is designed in such a way that it at least partially thermally insulates the fluid conducting channel and the cooling channel from one another.

In one embodiment, the at least one material recess is filled and/or traversed by air, preferably ambient air.

In a further embodiment, the at least one material recess forms a (for example thermally insulating) air gap (e.g. with a gap size greater than or equal to 5 mm and/or smaller than or equal to 15 mm) between the fluid duct and the cooling duct.

In a further embodiment, the at least one material recess is filled (eg partially or completely) with a thermal insulation material.

In one embodiment variant, an outer contour of the at least one material recess follows an outer contour of the fluid duct and/or the cooling duct at least in sections, preferably at a substantially constant distance.

In a further embodiment variant, the at least one material recess surrounds the fluid duct in sections or completely.

In a further embodiment variant, the at least one material recess has a cross section in the form of a ring segment and/or is designed in the form of a sleeve segment.

In one embodiment, the at least one material recess follows the fluid duct along at least 50%, 60%, 70%, 80% or 90% of a length of the fluid duct, preferably at a substantially constant distance.

In another embodiment, the at least one material relief terminates adjacent to a cylinder head base portion of the main body.

In a further exemplary embodiment, the at least one material cutout opens into an outer surface (for example the lateral surface) of the cylinder head, preferably to enable air to circulate through the at least one material cutout.

For example, the at least one material recess can extend from an opening in a lateral surface of the main body to adjacent to the cylinder head base area of the main body, for example in a curved shape, through the main body.

In a further exemplary embodiment, the at least one material recess essentially completely encloses the fluid duct, with the exception of a cylinder head base area of the main body and/or a support area of the main body required to support the fluid duct.

In one embodiment, the at least one material recess at least partially encloses the fluid duct.

In a further embodiment, the at least one material cutout has a plurality of cutout areas. Preferably, the plurality of recessed areas are in fluid communication with one another, preferably through passages in the main body. It is possible that the plurality of cut-out areas are arranged symmetrically around the fluid guiding channel. It is also possible for the plurality of cut-out regions to each have a ring-segment-shaped cross-section and/or to surround the fluid-guiding channel together in a ring-shaped manner. It is also possible that the plurality of cut-out areas are each formed in the shape of a sleeve segment and/or together surround the fluid conducting channel in the shape of a sleeve.

In one embodiment variant, the material thickness of the main body between the fluid duct and the at least one material recess is greater than or equal to 5 mm and/or less than or equal to 10 mm.

In a further embodiment variant, a material cutout thickness of the at least one material cutout is preferably greater than or equal to 5 mm and/or less than or equal to 15 mm in a radial direction of the fluid duct.

In a further exemplary embodiment, the fluid duct has an opening on an outside of the cylinder head and the at least one material recess has an opening on the outside of the cylinder head. Preferably, the opening of the at least one material recess surrounds the opening of the fluid duct at least partially, preferably in the form of a ring segment.

In a further development, a preferably ring-shaped web section is formed between the opening of the fluid conducting channel and the opening of the at least one material recess. The web section preferably has at least one fastening device, preferably a threaded hole, for attaching a fluid line in fluid communication with the fluid conducting channel.

In one embodiment, the main body has a support area that is arranged (e.g. with respect to a radial direction of the fluid duct) between the fluid duct and the at least one material recess for supporting the fluid duct in the main body. Alternatively or additionally, the at least one material cutout is designed to be fluidically separate from the fluid conducting channel, for example by means of the support area.

In a further embodiment, the cooling duct is arranged for cooling a cylinder head base area of the main body and/or adjacent to a cylinder head base area of the main body.

The invention also relates to a motor vehicle, preferably a commercial vehicle (e.g. truck or bus, with a cylinder head as disclosed herein.

It is also possible to use the device as disclosed herein for passenger cars, off-road vehicles, large engines, stationary engines, marine engines and so on.

The present disclosure also relates to a method of manufacturing a cylinder head, preferably configured as disclosed herein. The method includes primary shaping (e.g. casting and/or printing) of the main body of the cylinder head, the at least one material recess being produced in the main body directly during primary shaping of the main body and/or subsequent to the primary shaping of the main body.

Figur 1

eine perspektivische Ansicht eines Bereichs eines schematisch dargestellten Zylinderkopfes gemäß einem Ausführungsbeispiel der vorliegenden Offenbarung;

Figur 2

eine Seitenansicht des Bereichs des beispielhaften Zylinderkopfes;

Figur 3

eine Schnittansicht des Bereichs des beispielhaften Zylinderkopfes entlang der Linie A-A in Figur 2;

Figur 4

eine Schnittansicht des Bereichs des beispielhaften Zylinderkopfes entlang der Linie B-B in Figur 2;

Figur 5

eine Schnittansicht des Bereichs des beispielhaften Zylinderkopfes entlang der Linie C-C in Figur 4;

Figur 6

eine Schnittansicht des Bereichs des beispielhaften Zylinderkopfes entlang der Linie D-D in Figur 2;

Figur 7

eine Schnittansicht des Bereichs des beispielhaften Zylinderkopfes entlang der Linie E-E in Figur 2; und

Figur 8

eine Schnittansicht des Bereichs des beispielhaften Zylinderkopfes entlang der Linie F-F in Figur 2.

The preferred embodiments and features of the invention described above can be combined with one another as desired. Further details and advantages of the invention are described below with reference to the accompanying drawings. Show it:

figure 1

a perspective view of a portion of a cylinder head shown schematically according to an embodiment of the present disclosure;

figure 2

Figure 12 is a side view of the example cylinder head portion;

figure 3

14 is a sectional view of the portion of the example cylinder head along line AA in FIG figure 2 ;

figure 4

12 is a sectional view of the portion of the example cylinder head along line BB in FIG figure 2 ;

figure 5

12 is a sectional view of the portion of the example cylinder head taken along line CC in FIG figure 4 ;

figure 6

12 is a sectional view of the portion of the example cylinder head taken along line DD in FIG figure 2 ;

figure 7

12 is a sectional view of the portion of the example cylinder head taken along line EE in FIG figure 2 ; and

figure 8

12 is a sectional view of the portion of the example cylinder head along line FF in FIG figure 2 .

The embodiments shown in the figures correspond at least in part, so that similar or identical parts are provided with the same reference symbols and, for their explanation, reference is also made to the description of the other embodiments or figures in order to avoid repetition.

the Figures 1 to 8 12 show a region of a cylinder head 10, shown schematically. The cylinder head 10 can be designed as a single-cylinder cylinder head or as a multi-cylinder cylinder head. The cylinder head 10 can cover one or more combustion chambers 12 of an internal combustion engine, in particular a reciprocating internal combustion engine. The internal combustion engine can be included, for example, in a motor vehicle, preferably a commercial vehicle (for example a truck or bus).

The cylinder head 10 is cast. In other words, the cylinder head 10 has a main body 14 which is suitably metallic. The main body 14 can be manufactured by any known method. For example, the main body 14 can be cast, for example as a GJV cast body (cast iron with compacted graphite). It is also possible for the main body 14 to be printed using a 3D printer, for example.

Various structures are formed in the main body 14 by, for example, the casting process or the printing process. These include a cooling duct 16, a fluid duct 18 and preferably one or more cutouts or material recesses 20. In addition to the illustrated area of the cylinder head 10 shown schematically, the cylinder head 10 has other areas, preferably with one or more additional fluid ducts, one or more additional cooling ducts and /or valves, etc. In the main body 14 can also be formed, for example, a receptacle 28, for example, for a fuel injector.

The cooling duct 16 carries a cooling fluid, for example water, a water-coolant mixture or oil, for cooling the cylinder head 10. The cooling duct 16 can be designed as part of a water jacket of the cylinder head 10, for example. The illustrated cooling passage 16 is disposed adjacent to a cylinder head head portion 14A of the main body 14 of the cylinder head 10 for cooling the combustion chamber side of the cylinder head 10.

The fluid duct 18 serves to supply a fluid to the combustion chamber 12 or to discharge a fluid from the combustion chamber 12. The fluid duct 18 is particularly preferably designed as an exhaust gas duct for discharging exhaust gas from the combustion chamber 12. However, it was recognized that the material recess 20 also has advantageous effects if the fluid duct 18 is designed, for example, as an inlet duct for supplying inlet air to the combustion chamber 12 or as a compressed air extraction duct for discharging compressed air from the combustion chamber 12.

The fluid duct 18 has an opening 22 on the combustion chamber side. The fluid duct 18 has an opening 24 in an outer side, preferably a lateral surface, of the cylinder head 10 . The fluid duct 18 extends, preferably curved, between the opening 22 and the opening 24. The fluid duct 18 can be sealed on the combustion chamber side by means of a valve 26, preferably a poppet valve, of the cylinder head 10.

The material recess 20 is arranged between the fluid duct 18 and the cooling duct 16 . The material recess 20 thermally decouples the fluid duct 18 from the cooling duct 16. The material recess 20 significantly reduces heat transfer between the fluid duct 18 and the cooling duct 16, i. H. significant.

In the particularly preferred exemplary embodiment with the fluid duct 18 designed as an exhaust gas duct, this makes it possible for the heat transfer between the exhaust gas and the cooling fluid in the cooling duct 16 to be greatly reduced. A lower heat input into the cooling fluid leads to a reduction in the cooling requirement, which enables an improved design of the cooling system. This makes it possible, for example, to reduce fuel consumption by the internal combustion engine, for example also by saving energy when driving a coolant pump. In addition, the thermal decoupling means that the exhaust gas flowing through the fluid duct 18, which has a temperature of around 600° C., for example, cools less severely. As a result, more exhaust gas enthalpy is available for an exhaust gas turbocharger that may be arranged downstream. Alternatively or additionally, more exhaust gas enthalpy may be available for an exhaust gas aftertreatment device that may be arranged downstream. For example, the exhaust aftertreatment device may require a certain high temperature range to operate effectively (for example, with an SCR catalyst). This enables improved design and efficiency of these components and a reduction in fuel consumption.

However, the material recess 20 can also be used, for example, for the thermal decoupling of a fluid-guiding channel 18 designed as an inlet channel. In this case, the material recess 20 reduces heat transfer from the cooling fluid in the cooling channel 16, which has a temperature above 90° C., for example, to the inlet air flowing through the fluid duct 18, which preferably has a low temperature, for example below 40° C. or 50 °C.

Preferably, the material recess 20 is formed as a material recess directly during primary molding (e.g., printing or casting) of the main body 14, e.g. B. as casting material recess. However, it is also possible for the material recess 20 to be formed in the main body 14 only after the primary shaping of the main body 14, for example by means of a machining manufacturing process. For example, several bores surrounding the fluid duct 18 can be made in the main body 14 .

A support area 30 is arranged between the material recess 20 and the fluid duct 18 . The support portion 30 is part of the main body 14. The support portion 30 is cast. The support area 30 supports the fluid guide channel 18 in the main body 14. The support area 30 fluidly separates the material recess 20 and the fluid guide channel 18 from one another. A material thickness of the support area 30 between the fluid duct 18 and the material recess 20 can be in a range between 5 mm and 10 mm, for example. The support area 30 is to be designed in such a way that it is as stiff as necessary to support the fluid duct 18 and as flexible as possible to compensate for, for example, temperature-related material expansions.

The material recess 20 is filled with air, preferably ambient air. As a result, the material recess 20 forms a heat-insulating air gap between the fluid duct 18 and the cooling duct 16. The size of the air gap can be in a range between 5 mm and 15 mm, for example. It can also be possible that the material recess 20 is at least partially filled with a thermal insulation material.

The material recess 20 may be open to an outside of the main body 14 . This enables the air in the material saving 20 to be exchanged with the ambient air and air circulation results. However, it is also possible for the material recess 20 to be arranged as a cavity in the main body 14 without opening to the outside.

The outer contour or wall contour of the material recess 20 is adapted to an outer contour or wall contour of the fluid duct 18 and follows this, for example, at least partially at a constant distance. For example, the outer contour of the material cutout 20 can be formed at least partially as a cylinder jacket segment, on the inside of which the fluid duct 18 runs. It is also possible that the outer contour of the material cutout 20 is additionally or alternatively adapted to the cooling channel 16 and, for example, follows it at least partially at a constant distance.

Material recess 20 follows fluid duct 18 from an exterior of cylinder head 10 along a substantial portion of a length of fluid duct 18. As illustrated, material recess 20 may follow fluid duct 18 for between 80% and 90% of the length of fluid duct 18, for example. The material recess 20 encloses the fluid duct 18, with the exception of the cylinder head base area 14A of the main body 14 and the support area 30 of the main body 14, substantially completely.

In the exemplary embodiment shown, the material cutout 20 has two cutout areas 32 , 34 . The relief areas 32, 34 are in fluid communication with each other via a plurality of passages 36, as shown. It is also possible to provide more or fewer relief areas, which may or may not be in fluid communication with each other.

The recess areas 32, 34 are arranged in a ring around the fluid duct 18 around. The recess areas 32, 34 can surround the fluid duct 18 symmetrically, for example. The recess areas 32, 34 each have a ring-segment-shaped cross-section. The cross sections in the form of ring segments can, for example, each comprise an angular range of approximately 180°. The recess areas 32, 34 follow a course of the fluid duct 18 in the form of sleeve segments.

The relief portions 32, 34 end adjacent to the cylinder head bottom portion 14A of the main body 14. On the other hand, the relief portions 32, 34 open to an outside of the main body 14. The relief portions 32, 34 have an opening 38, 40, respectively. The openings 38, 40 are arranged around the opening 24 around. The openings 38, 40 have a ring segment shape. Air can flow into and out of the recess areas 32 , 34 through the openings 38 , 40 , so that air can circulate in the recess areas 32 , 34 and thus in the material recess 20 .

A web section 42 of the support area 30 is arranged between the opening 24 on the one hand and the openings 38, 40 on the other hand. The land portion 42 may be annular. The web portion 42 surrounds the opening 24. The web portion 42 may include one or more fasteners 44 (only in figure 2 shown schematically) which are designed to connect a fluid line to the fluid duct 18 . For example, the fastening devices 44 can be designed as threaded holes for screwing in fastening screws.

The invention is not limited to the preferred embodiments described above. The scope of the invention is defined in the appended claims.

Reference List

10

cylinder head

12

combustion chamber

14

main body

14A

cylinder head floor area

16

cooling channel

18

fluid guide channel

20

material recess

22

opening

24

opening

26

Valve

28

recording

30

support area

32

recess area

34

recess area

36

channel

38

opening

40

opening

42

web section

44

fastening device

Claims (15)

1. Cylinder head (10) for covering a combustion chamber (12) of an internal combustion engine, having:

   a fluid conducting duct (18) for feeding in a fluid to or discharging a fluid from the combustion chamber (12); and

   a cooling duct (16) for a cooling fluid for cooling the cylinder head (10);

   characterized by:
   at least one material cutout (20) for thermal insulation, which at least one material cutout (20) is formed in a main body (14) of the cylinder head (10) and is arranged between the fluid conducting duct (18) and the cooling duct (16), the at least one material cutout (20) being arranged such that it is separated from the fluid conducting duct (18) by way of the main body (14).
2. Cylinder head (10) according to Claim 1:

   the at least one material cutout (20) being produced by way of primary forming, reshaping and/or cutting; and/or

   the main body (14) being cast or printed; and/or

   the at least one material cutout (20) being formed during the primary forming, preferably during the casting or printing, of the main body (14) or subsequently thereto, preferably by way of a cutting production method.
3. Cylinder head (10) according to Claim 1 or Claim 2:

   the fluid conducting duct (18) being configured as an exhaust gas duct, an inlet duct or a compressed air removal duct; and/or

   the cylinder head (10) having a valve (16), preferably a poppet valve, which is arranged for sealing the fluid conducting duct (18) on the combustion chamber side; and/or

   the cooling duct (16) being arranged for cooling a cylinder head bottom region (14A) of the main body (14); and/or

   the cooling duct (16) being arranged adjacently with respect to a cylinder head bottom region (14B) of the main body (14).
4. Cylinder head (10) according to one of the preceding claims, the at least one material cutout (20) being configured such that it:

   (preferably substantially) reduces a transmission of heat between the cooling duct (16) and the fluid conducting duct (18); and/or

   insulates the fluid conducting duct (18) and the cooling duct (16) thermally from one another at least partially.
5. Cylinder head (10) according to one of the preceding claims:

   the at least one material cutout (20) being filled with and/or flowed through by air, preferably ambient air; and/or

   the at least one material cutout (20) forming an air gap between the fluid conducting duct (18) and the cooling duct (16); and/or

   the at least one material cutout (20) being filled with a thermal insulation material.
6. Cylinder head (10) according to one of the preceding claims:

   an outer contour of the at least one material cutout (20) following an outer contour of the fluid conducting duct (18) and/or of the cooling duct (16) at least in sections, preferably at a substantially constant spacing; and/or

   the at least one material cutout (20) surrounding the fluid conducting duct (18) in sections or completely; and/or

   the at least one material cutout (20) having a ring segment-shaped cross section and/or being of sleeve segment-shaped configuration.
7. Cylinder head (10) according to one of the preceding claims:

   the at least one material cutout (20) following the fluid conducting duct (18) along at least 50%, 60%, 70%, 80% or 90% of a length of the fluid conducting duct (18), preferably at a substantially constant spacing; and/or

   the at least one material cutout (20) ending adjacently with respect to a cylinder head bottom region (14A) of the main body (14); and/or

   the at least one material cutout (20) opening into an outer face of the cylinder head (10), preferably in order to enable a circulation of air through the at least one material cutout (20).
8. Cylinder head (10) according to one of the preceding claims:

   the at least one material cutout (20) enclosing the fluid conducting duct (18) substantially completely with the exception of a cylinder head bottom region (14A) of the main body (14) and a supporting region (30) of the main body (14), which supporting region (30) is required for the support of the fluid conducting duct (18); and/or

   the at least one material cutout (20) enclosing the fluid conducting duct (18) at least partially.
9. Cylinder head (10) according to one of the preceding claims, the at least one material cutout (20) having a plurality of cutout regions (32, 34) which:

   are connected fluidically to one another, preferably by way of ducts (36) in the main body (14), and/or

   are arranged symmetrically around the fluid conducting duct (18); and/or

   in each case have a ring segment-shaped cross section and together surround the fluid conducting duct (18) in an annular manner; and/or

   are in each case of sleeve segment-shaped configuration and together surround the fluid conducting duct (18) in a sleeve-shaped manner.
10. Cylinder head (10) according to one of the preceding claims:

    a material thickness of the main body (14) between the fluid conducting duct (18) and the at least one material cutout (20) being greater than or equal to 5 mm and/or less than or equal to 10 mm; and/or

    a material cutout thickness of the at least one material cutout (20) in a radial direction of the fluid conducting duct (18) being greater than or equal to 5 mm and/or smaller than or equal to 15 mm.
11. Cylinder head (10) according to one of the preceding claims:

    the fluid conducting duct (18) having an opening (24) on an outer side of the cylinder head (10); and

    the at least one material cutout (20) having an opening (38, 40) on the outer side of the cylinder head (10), which opening (38, 40) surrounds the opening (24) of the fluid conducting duct (18) at least partially, preferably in a ring segment-shaped manner.
12. Cylinder head (10) according to Claim 11:
    a preferably annular web section (42) being formed between the opening (24) of the fluid conducting duct (18) and the opening (38, 40) of the at least one material cutout (20), which web section (42) has at least one fastening device (44), preferably a threaded hole, for the attachment of a fluid line in a fluidic connection to the fluid conducting duct (18).
13. Cylinder head (10) according to one of the preceding claims:

    the main body (14) having a supporting region (30) which is arranged between the fluid conducting duct (18) and the at least one material cutout (20) for the support of the fluid conducting duct (18) in the main body (14); and/or

    the at least one material cutout (20) being configured such that it is separated fluidically from the fluid conducting duct (18).
14. Motor vehicle, preferably a utility vehicle, with a cylinder head (10) according to one of the preceding claims.
15. Method for the production of a cylinder head (10) according to one of the preceding claims, comprising:
    primary forming, preferably casting or printing, of the main body (14) of the cylinder head (10), the at least one material cutout (20) being produced in the main body (14) directly during the primary forming of the main body (14) and/or following the primary forming of the main body (14).

Images