WO2014198772A1

WO2014198772A1 - Heat shield

Info

Publication number: WO2014198772A1
Application number: PCT/EP2014/062127
Authority: WO
Inventors: Axel Ritzal; Benjamin WITTMANN; Alexander KEILICH; Martin Wuchenauer
Original assignee: Reinz-Dichtungs-Gmbh
Priority date: 2013-06-11
Filing date: 2014-06-11
Publication date: 2014-12-18
Also published as: DE112014002785T5

Abstract

Heat shield (1) for shielding of an object against heat and/or sound with at least one metallic layer (2, 3), with at least one metallic layer (2) situated at a surface of the heat shield (1) comprises a micro structuring (29), wherein a laminar marking element (11) is applied to the surface and/or embedded into the at least one micro-structured layer (2), with the laminar marking element (11) being positively and/or frictionally connected to the at least one micro-structured layer (2) of the heat shield (1).

Description

Heat shield

[0001] The invention relates to a heat shield for the shielding of an object against heat and/or sound with the heat shield comprising at least one layer. Heat shields serve for instance in engine compartments in vehicles, in particular in the area of the exhaust line for the protection of temperature-sensitive objects which are located close to hot parts against non-permissible overheating. In most cases, the heat shields also improve the protection against sound.

[0002] Usually, such heat shields are constructed as three-dimensionally formed structural parts with at least one extended plate which comprises at least one micro-structured layer, e.g. a metallic layer and in cases further metallic or non-metallic layers. In a first embodiment, it is preferred that an air buffer remains between the object to be shielded and the heat shield as well as between the heat-carrying part and the heat shield over a large part of the area of the parts so that the heat transfer caused by direct contact of the parts can be reduced to a minimum. Such heat shields are fastened to at least one, preferably to at least two points, with the fastening being usually realized at the heat-carrying part. In such a construction, the three-dimensional form of the heat shield usually results from the shape of the heat-carrying parts and their distance to the adjacent parts. In a second embodiment, the heat shield rests immediately on the heat-emitting part and encapsulates the heat- emitting part towards the outside, preferably on its complete surface. With this, the adjacent parts are shielded against this heat radiation. In this context, it is advantageous, if the heat shield also comprises an insulating layer which immediately rests on the heat-source and which is covered by the at least one micro-structured layer. The three-dimensional shaped then immediately results from the shape of the part that is surrounded. In addition to the actual insulation against heat and structure-born sound, this construction also leads to a reduction of the convection of the warm air. Further, vibrations are absorbed.

[0003] In order to improve the insulating and acoustical properties, at least the outermost, in particular metallic, layer of the heat shield comprises micro structures, e.g. dimplings and/or other embossments or micro perforations. Dimpled heat shield layers improve the stability of the heat shield and allow for the production of heat shields with non-modified stability with thinner and therefore lighter metal sheets. [0004] In thermally and acoustically active heat shields, micro-perforated layers are preferably oriented towards the source of sound so that the sound waves may enter through the micro- perforations into the heat shields and then be absorbed in the inner space of the heat shield. When combined with a micro-perforated layer, a dimpled layer arranged behind the former, which may then for instance point towards the visible face, may then form resonating cavities. In the same way, it is possible to achieve a good sound absorption when a fiber-based insulating layer is arranged behind the micro-perforated layer, as the free spaced in this insulating layer also allows for the formation of resonating cavities.

[0005] While in former times, markings have been applied by letterings to vehicular parts, it becomes increasingly customary to codify such markings such as the producer name and/or the time of production and/or the part number. The so-called data-matrix code, a two-dimensional, in total quadratic arrangement of points or squares has been established, also for heat shields.

[0006] With heat shields with smooth surfaces, there is no difficulty to print-on, apply by laser or form-in this data-matrix code. With heat shields with micro-structured surface, it is however not possible to apply a data-matrix code in a readable manner as its structures overlap with the micro structure of the corresponding layer and interfere with each other.

[0007] In the state of the art, it has been tried to apply marking elements to micro-structured layers on the surface of heat shields by adhesive methods. It has in particular been tried to weld-on such marking elements. To do so, on the one hand, additional production installations are required as the production of heat shield usually is done without welding. This results in a considerable price increase. On the other hand, the vibrations given in the engine compartment cause the marking element to detach itself so that the marking element does not remain reliably fastened on the heat shield layer for the life time of the heat shield. Further, welding of micro-structured layers, in particular of thin micro-structured layers has turned out to be difficult as they offer only very small continuous areas in which the layers rest immediately one on the other. The micro structuring provides for a lot of zones with no direct contact between the layers. With heat shields with at least one fiber-based insulating layer one is further faced with the risk that the high energy input leads to local damages of the insulating layer(s).

[0008] It has also been tried to attach the marking elements by means of separate fastening means. This way, one could achieve an improved residence time of the marking element on the surface of the heat shield, but this approach also did not last for the entire life time of the heat shield. These fastening methods require additional installation equipment, too, which is not present as standard equipment in the production of heat shields and this way increase the production time and the cost for the production of a heat shield. Procurement and installation of the additional fastening elements, such as rivets, additionally complicates the production of the heat shield and makes it more expensive.

[0009] It is thus the object of the present invention to provide a heat shield which comprises at least one micro-structured layer, where a well-readable marking can nevertheless be applied to the micro- structured layer. The micro-structured layer shall be producible from conventional material and the production shall be simple and cost-efficient. It is preferred that the production can be achieved without additional steps such as welding or riveting.

[0010] This is accomplished with a heat shield according to claim 1. Preferred embodiments are given in the dependent claims.

[0011] The invention thus relates to a heat shield for shielding of an object against heat and/or sound with at least one metallic layer. At least one metallic layer arranged on the surface of the heat shield comprises a micro structuring. A laminar marking element has been applied to the surface or has been inserted into the at least one micro-structured layer and is positively and/or frictionally connected to the at least one micro-structured layer. The positive and/or frictional connection does not necessarily have to be formed immediately by the micro-structured layer and the marking element. Rather, other parts or elements of the heat shield may contribute to this connection.

[0012] As the laminar marking element can be formed as an additional part, the micro-structured layer of the heat shield can be produced from conventional material such as a material which has been micro-structured as a coil. The application or embedding of the marking element makes it possible to apply the marking to a non-structured surface, so that it is well readable. The positive and/or frictional connection of the marking element with the heat shield or at least its micro- structured layer allows to doing without expensive fastening methods between the first metallic layer and the marking element, such as welding or riveting. The positive and/or frictional connection can for instance be applied during the three-dimensional forming of the heat shield which is anyway required and therefore in most cases requires neither additional production systems nor prolonged cycle times for the production. With multi-layered heat shields, the marking element can for instance also be positively and/or frictionally connected to at least one of these layers during the fastening of the layers one on the other.

[0013] In a first embodiment, the invention comprises multi-layered heat shields where at least one micro-structured layer is preferably arranged on the outer surface of the heat shield, while the other at least one layer is arranged further away from the outer surface of the heat shield, preferably on the inner surface of the heat shield. With this arrangement of heat shield layers, the laminar marking element is applied to the surface of the at least one micro-structured layer on the surface pointing away from the outer surface of the heat shield, namely between the at least one micro-structured layer and the at least one further layer. If no further layer is given, the marking element may also rest directly on the part surrounded by the heat shield.

[0014] In order to take up the marking element, the at least one micro-structured layer preferably comprises at least one take-up area, with the micro-structured layer comprising at least one clearance, which, comparable to a window, allows to read the marking element arranged below. The edge areas of the marking element here are covered in a frame-like manner. In the neighborhood of the at least one clearance, the take-up area of the micro-structured layer in a first variant shows at least one, preferably several passage openings, which are in particular slit-shaped or oblong. In a second variant, in the neighborhood to the recess of the take-up area, protrusions are formed at least in sections, which protrusions preferably point from the outer surface of the heat shield towards the inner surface of the heat shield.

[0015] The laminar marking element in turn preferably at its outer edge at least in sections comprises at least one projection, which after installation of the laminar marking element in the heat shield points in the direction of the outer surface of the heat shield. The projection is preferably bent by an angle of at least 60°, preferably at least 80° from the plane of the laminar marking element, where the bending does not need to be realized at a single bending line, but may also extend over a bending area. In its further course starting at the first bending area, a projection may comprise further bending lines or bending areas. With several bendings, its free edge may also extend in parallel to the plane of the laminar marking element. The projection may be formed as a short lug, it may however also extend along an entire peripheral edge of the laminar marking element and be correspondingly bent from the plane of the marking element.

[0016] If, as described before, the micro-structured layer of the heat shield comprises one or several passage openings, then it is preferred if the at least one projection passes through the at least one passage opening and is reshaped, folded-over and/or compressed on the outer surface of the heat shield in order to achieve a fastening. It is preferred that the number of projections of the marking element corresponds to the number of passage openings. Alternatively, several projections, in particular such projections, which are arranged one adjacent to the other, can be fed through a single, in particular an elongate, passage opening. The reshaping is preferably realized in such a manner that that part of the projection which exceeds beyond the passage opening is folded over or compressed in such a way that it laterally exceeds beyond the passage opening and this way enables a positive connection. [0017] In a preferred variation, that section of the projections, which protrudes beyond the passage opening is folded back or crimped over to the surface of the micro-structured layer. In this context it is possible that if the protruding part of the projection reaches into the clearance, the free end can come to rest on the surface of the laminar marking element which is visible through the clearance and may even be pressed to this surface of the marking element. In the last mentioned case, in particular if the thickness of the material of the marking element is equal to or smaller than the thickness of the material of the micro-structured layer, a protrusion of the free end of the projection is avoided, so that the risk of any physical in jury is minimized. The same is true with a short free end, which is folded over downwards in the direction of the marking element along the peripheral edge of the micro-structured layer.

[0018] In another advantageous variant of the invention, the part of the projection which protrudes beyond the passage opening is compressed to the surface of the micro-structured layer so that a button-shaped area results, which on at least two sides, preferably circumferentially, covers the passage opening. It is also possible that the projection inside the section which protrudes beyond the passage opening is provided with a slit and with pre-embossments at the ends and at half the length of the slit. This way, when compressing the protruding section of the projection, a folding can be achieved. The two folded-back sections also provide for a positive connection between the marking element and the micro-structured layer.

[0019] However, if the micro-structured layer of the heat shield, as mentioned beforehand, too, comprises at least one protrusion, then it is preferred if the at least one projection comes to lie between the at least one protrusion of the take-up area in the micro-structured layer and the at least one further layer and this way is clamped onto the at least one further layer by the protrusion. It is preferred if both the at least one protrusion is pre-shaped in the direction of the marking element and the at least one projection is pre-shaped in the direction of the outer surface of the heat shield, in particular, folded over. During the assembly, the pre-shaping can be further adapted, e.g.

compressed. In this variant, it is possible that the micro-structured layer comprises several such protrusions or one elongated protrusion not only at one edge of the clearance, but preferable at two, in particular on two edges of the clearance situated opposite to each other. The projections may also consist in short sections or be realized as an oblong projection along at least one preferably however along two edges of the laminar marking element which edges are opposite to each other.

[0020] The fastening is improved if the laminar marking element as a whole or at least the at least one projection of the marking element at least in sections comprises an undulating or serrated edge. This undulating and/or serrated edge can positively grip into the micro structure of the at least one micro-structured layer if the size of the waves or prongs and their distance is adapted to the micro structure. This way, a loosening of the connection can be prevented from.

[0021] As an alternative or in addition to the foregoing, the connection can be improved by a suitable support of the projection(s) or the marking element on the side pointing away from the marking field of the marking element. In a first variant, a cranking is formed at least in sections into the at least one micro-structured layer adjacent to the at least one protrusion on the side of the protrusion pointing away from the clearance. Thus, the cranking and the protrusion together form a groove with a greater or lesser extent, into which the projection is taken up.

[0022] In a second variant, the support is realized by a further layer of the heat shield. This further layer in the area of the take-up area of the micro-structured layer at least in sections forms at least one recess. The at least one projection of the laminar marking element here is now preferably taken up between the at least one protrusion of the take-up area of the micro-structured layer and the at least one edge of the at least one recess. In this context, the supporting effect may be realized by the lateral edges and/or the bottom of the recess if the recess is essentially orthogonal. Inclined edges are feasible as support, too.

[0023] A further embodiment of the invention provides that the marking element comprises at least one projection, which other than in the embodiments described beforehand, does not point towards the outer surface of the heat shield but away from the micro-structured layer. Here, it is

advantageous if prolongations adjoin to the projection(s), which prolongations point away from the marking field of the marking element. In this context, it is advantageous if an angle between about 80 and 100°, preferably a right angle is spanned between the surface of the marking element and the projections on the one hand and if an essentially opposite angle is formed between the projections and their prolongations on the other hand. The free ends of the prolongations preferably extend at least almost parallel to the surface of the marking element. It is preferred if a recess in the layer on which the marking element lies, is given here as well, in which the marking element is taken-up and supported. This solution is particularly preferred with heat shields comprising a micro-structured outer layer and a fiber-based insulating layer as inner layer.

[0024] In addition to the connecting methods mentioned above, it is also possible to use connecting elements which are anyway used for the connection of the layers of the heat shield with one another in order to strengthen the positive fit between the heat shield and the marking element. Braces or clips can for instance be used as fastening elements. It is particularly preferred if the connection using braces or clips is made through the marking element and some or all heat shield layers. For some braces or clips, it may be necessary to adapt the layers of the heat shield so that the fastening elements can be most easy been taken up. It may for instance be required to provide for recesses in which parts of these fastening elements are taken up. While some fastening elements are able to penetrate the layers without any pretreatment, there are combinations of fastening elements and layer characteristics, where it is necessary to provide holes for the passage of the fastening elements.

[0025] A further embodiment of the invention provides for the marking element being taken up on the outer surface of the at least one micro-structured layer so that it becomes attached from the outside. In order to achieve a positive and/or frictional fastening of the marking element at the heat shield, it is here preferred if at least the micro-structured layer of the heat shield comprises a local recess, e.g. a bowl-like immersion or a deep-drawn or embossed cup which takes up the marking element. When forming this take-up area, it is possible that the micro-structure in this area is altered. The recess at least in one facial dimension shows a slightly smaller extension than the marking element before the fastening of the marking element. In the direction orthogonal to this, the recess may be larger than the marking element. The marking element comprises recesses and/or projections on at least one, preferably on at least two outer edge sections, which when installing the marking element into the take-up area get caught in the outer edge of the take-up area. Projections with an undulating and/or serrated edge are particularly preferred to get caught. The projections get at least positively caught, with elastic materials of the marking element also frictionally.

[0026] In other embodiments, the marking element is only positively connected with the at least one micro-structured layer of the heat shield. Here, either the entire heat shield or the micro- structured layer is reshaped in at least two areas so that setbacks are formed which are able to take up the marking element. The distance between the setback and the area of the heat shield which comes to lie below the marking element here needs to be at least as large as the thickness of the marking element. If the marking element has areas with different height, the areas that are held by the setbacks determine the height in this respect. The reshaping can then be realized in such a way that the marking element is applied to the respective position right before the reshaping and is connected with the heat shield or the micro-structured layer during the reshaping. As an alternative which can only be used with a resilient marking element, the heat shield or its micro-structured layer may be reshaped first and the resilient marking element is inserted only subsequently.

[0027] A particularly stable foothold of the marking element results, if the at least two outer edge sections of the marking elements are clamped on their upper and lower side by the micro-structured layer. With respect to acoustics, it is here preferred if the outer edge section of the marking element and the two sections of the micro-structured layer at least in sections come to rest immediately one on the other and are frictionally compressed. This way one can avoid that the marking element retains the ability to move and cause noise. With this embodiment, it is sufficient if two outer edge sections of the marking element which are located one opposite to the other are frictionally compressed so that no lateral movement is possible.

[0028] The embodiments where the marking element is attached to the micro-structured layer from the side which in the ready-made heat shield is the outer surface are particularly suited for one- layered heat shields.

[0029] In multi-layer heat shields, the at least one further layer may be a structured or non- structured metallic layer. The thickness of this at least one layer in the area of the at least one recess is then essentially equal to its thickness outside of the at least one recess. The recess is thus formed by a local displacement of the metallic layer, e.g. as a cup-shaped recess or spans the area of the marking element like an arc.

[0030] The at least one further layer in a multi-layer heat shield may however also be an insulating layer. As already mentioned, the insulating layer may show an unaltered thickness in the area of the clearance of the micro-structured layer. Alternatively, the layer thickness is preferably reduced in the area of the at least one recess compared to the layer thickness outside the at least one recess. If the insulating layer is composed of several individual layers, at least one of these individual layers may be left out in the area of the recess. With a one-layered insulating layer, the reduction of the thickness in the area of the recess can for instance be realized by a local compression. This can apply no matter whether the marking element is attached or embedded.

[0031] With respect to the marking element, there exist several opportunities for its production process and design. On the one hand, it is possible that the heat shield is first produced in such a way that the laminar marking element shows a non-structured surface. Thus, no marking has been applied yet. The final marking of the marking in this case is done by the producer of the engine or of the vehicle.

[0032] On the other hand, it is also possible that the laminar marking element is marked right during the production of the heat shield and that the heat shield thus shows a marking immediately after its production. The marking element may already have been marked before it is fastened or only after its fastening. It is also feasible that a part of the marking is done during the production of the heat shield and that the producer of the engine or vehicle completes the marking.

[0033] For the application or insertion of the marking, one can select from a large variety of methods. On the one hand, there are printing methods. Here, one has to take care that the ink or other color used has a sufficient stability against the temperatures to be expected during the operation of the heat shield and if the heat shield is exposed to oil that it is sufficiently stable against oil. On the other hand, the marking can be applied into the surface of the marking element, so that a structuring of the surface takes place. Marking by laser is particularly advantageous. It is however also possible to emboss the marking or to punch out the marking. Engraving, e.g. using needles, or etching are generally possible, too. Engraving, embossing, punching-out and etching are particularly advantageous with respect to their long-term durability and readability. It is also possible that an additional adhesive label is attached for marking purposes during the production process, which can be peeled off, e.g. at the final control at the end of the production process. The marking element may also be provided with a protective adhesive film covering the actual marking, which may e.g. serve for protection purposes during transport or during production. It is both possible that it is peeled-off at a certain production stage, at the end of production, or that it remains in place in the ready-made car. Such adhesive labels have a significantly better bonding on a non-structured or only slightly structured, e.g. printed, surface as with the marking element than on a micro-structured layer.

[0034] With respect to the stability of the entire heat shield against heat, it is advantageous if the marking element consists of metal, in particular in steel or in aluminum alloy or comprises metal, in particular steel or an aluminum alloy. If the marking element is installed on the surface of the heat shield which points way from the source of heat, as this is in particular the case with heat shields that are immediately mounted on the heat-emitting part, it is also possible that the marking element consists in a thermoplastic or thermoset material or comprises a thermoplastic or thermoset material.

[0035] One can also use marking elements, which consist in a metal-plastic compound, e.g. a disk from plastic which is surrounded by a metallic frame. This way the mechanical strength of the marking element in the fastening areas is improved while all possibilities for the marking of plastic surfaces can be used.

[0036] A further advantage of the marked heat shields according to the invention results as it allows for a large variety of marking elements to be attached or embedded. This includes marking elements which have been provided, designed or specified by the producer of the engine or of the car which are nevertheless installed by the producer of the heat shield.

[0037] The micro-structuring of the heat shield can be realized as a dimpling. With a dimpling the heat shield can be provided with a surface and/or entire shape that is particularly resistant with respect to bending. The dimpling preferably shows a regular pattern, which may however show non regular structures, in particular in lengthened or compressed areas of the heat shield which result from the three-dimensional forming of the entire heat shield. [0038] The dimpling can be optimized for the particular use by setting several parameters. In addition to the preferred, essential round shapes of the dimples, other, e.g. oval shapes of the dimples are possible as well. In addition, approximately rectangular embossment patterns which in a checkerboard pattern are deformed against each other are also comprised in the term "dimpling" in the context of this invention. Particularly suited dimpling geometries result when one of the following parameters or a combination of them is used for at least one dimple:

- a height of the dimple(s) between 0.8 and 20 mm, preferably between 1 and 15 mm, particularly preferably between 3 and 10 mm,

- a diameter or width of the dimple(s) in the largest extension direction between 1 and 20 mm, preferably between 3 and 10 mm,

- an extension of one dimple on the surface between 3 and 500 mm², preferably between 10 and 70 mm²,

- a flank angle of the dimple(s) between 20 and 90 °, preferably between 30 and 60 °,

- a distance between the crests of the dimples between 2.5 and 30 mm, preferably between 6 and 15 mm and/or

- a density of the dimples between 1 and 10, preferably between 1 and 6 dimples per square centimeter.

[0039] As an alternative or in addition, the micro structure may be realized as a micro perforation. This is particularly preferred with multi-layer heat shields. With the micro perforation, sound waves may enter between the layers of the heat shield and then are absorbed there. The micro perforation may be optimized for the respective use by setting a large number of parameters:

- a diameter of the micro perforation of between 0.05 mm and 3 mm, preferably between 0.08 mm and 1 mm,

- a density of the micro perforation of between 1 and 200, preferably between 3 and 100 holes per square centimeter and/or

- a percentage of the area of the holes in the total surface between 0.1 % and 20 %. The micro perforations are always smaller than the passage openings through which the projections are fed.

[0040] The dimensions mentioned for the micro structure(s) apply to the base material. With the three-dimensional forming of the heat shield, they may be stretched and/or compressed, sometimes even skewed in the areas of the heat-shield that have been formed. Thus, the dimensions given may only apply in those areas which have either not been reshaped or only been slightly reshaped.

[0041] The material of the at least one micro-structured layer is preferably an aluminum alloy or a steel, in particular a coated steel, preferably a fire-aluminated or aluminum-plated steel. For a lot of application, stainless steel is the material of choice. The thickness of the layer of the micro-structured layer is preferably between 0.1 and 0.5 mm.

[0042] The heat shield may be realized as a one-layer heat shield, it then consists in a single micro- structured layer. It is however preferred that the heat shield consists in at least two layers. In one embodiment, the heat shield comprises two metallic layers, at least one of them being micro- structured. Particularly advantageous absorption properties of the heat shield result from a combination of a micro-perforated cover layer and a dimpled layer, as here Helmholtz resonators form, the cavities of which provide for excellent sound-absorbing properties as well as for a good thermal insulation.

[0043] In another embodiment, the heat shield consists in at least one metallic layer, at least one of them being micro-structured and in one layer of insulating material, in particular of a fiber-based material. This can comprise or consist of a woven material, interlaced yarns, a crocheted material, a knitted material, a fiber roving or a fleece. It is preferred if the insulating material is made from mineral fibers, glass fibers, carbon fibers and/or composite fibers, which may additionally be impregnated and/or chemically modified. The insulating material may comprise further functions, such as sections with different thicknesses and/or channels for the guidance of air streams. The entire layer thickness of the insulating layer outside of the areas of the recesses preferably ranges between 1 and 100 mm, preferably between 1 and 40 mm. In particular the highest layer thicknesses will be present over the entire surface only in rare cases, but will usually only fill up a part or parts of a larger total area. The density of the insulating material often also varies over its surface. The density of non-impregnated or chemically non-modified fiber-based layers in general in the installed state ranges between 100 and 400 kg/m³, preferably between 120 and 300 kg/m³. With chemically modified or impregnated fiber-based insulating layers, especially with the addition of a binder or a stabilisator, the density in the installed state ranges between 110 and 500 kg/m³, preferably between 150 and 400 kg/m³.

[0044] The heat shield may be designed in such a way that after its installation an air buffer remains between the heat shield and the part to be shielded. However, in particular with heat shields with at least one micro-structured metallic layer and one insulating layer of fiber material, a contacting shielding is preferred as this allows to encapsulate the part to be shielded, in particular a source of heat, at least in sections and preferably entirely. With this, it is preferable when the insulating layer made of fiber-material immediately rests against the part to be shielded and is entirely surrounded by the micro-structured metallic layer. Here it is possible that the heat shield consists in several separate sections, which are combined during the installation. Individual sections may also be connected to each other via hinges or bending lines in a bendable manner. Their free edges then can come into contact when the heat shield is closed. In the same way it is possible that the heat shield consists in only one section. This single section may be formed individually for the at least one insulating fiber layer and for the at least one micro-structured metallic layer. It may however also be formed for both layers together, which are for instance pre-fixed or pre-mounted. Here again, the free edges are connected to each other at least in sections with the closure of the heat shield. In addition to the connecting methods and means known from the state of the art, a connection is also possible via the marking element. Namely, if the take-up area of the at least one micro-structured layer is distributed to two edge sections of the micro-structured layer which edge sections are to be connected to one another. If the marking element is connected with both edges sections in a positive and/or frictional manner, these two edge sections are connected to each other through the marking element so that the fiber-based insulating layer which is located on the inside is covered and enclosed.

[0045] While the heat shield as such may be completely closed or essentially closed with at least one in- and/or outlet omitted, it is also be possible that the heat shield as such only forms a half-shell which becomes closed during the installation as it is installed in such a way that e.g. a surface to which it is installed closes the heat shield completely or essentially.

[0046] In place of a data-matrix code or in addition to a data-matrix code, the marking field of the marking element may additionally be provided with number and/or letter sequence(s) and/or with one or several logo(s). The data-matrix code is preferably realized as a two-dimensional code, it is however also possible to apply a two-dimensional bar code. In the following, this is summarized and simplified in the term "marking".

[0047] The marking element does not need to have rectangular or square basic shape. It can rather be advantageous if - apart from the projections - it comprises protrusions and recesses in its plane, which are adapted to a corresponding geometry in the micro-structured layer, which in most cases will be additional to the actual micro structure. This way, it is possible that the marking element can only be installed in one installation position /orientation. Alternatively or in addition, the projections may be oriented in such a manner relative to the protrusions or passage openings that no wrong installation is possible. To this end, a non-symmetric arrangement of the projections is advantageous.

[0048] The marking element may also comprise a bridge-shaped section which can be deformed downwardly into the at least one further layer. If it comprises for instance lateral projections or hooks, it may this way additionally be connected to the fiber-based material of the insulating layer. [0049] Heat shields according to the invention are for instance used for shielding hot areas in combustion engines, in particular catalysts, exhaust manifolds, turbo chargers, sections of the exhaust line and the like, but also in the conditioning of batteries.

[0050] In the following, the invention is further explained by reference to some drawings. These drawings only serve for the explanation of preferred embodiments of the invention; the invention is not delimited to the embodiments shown in the drawings. Equal or similar parts in the drawings are referred to with equal or similar reference numbers and are not necessarily repeatedly described. The following examples illustrate a plurality of individual characteristics which may also be used in embodiments of the invention when isolated from the context of the respective example. The drawings are of schematic nature only, in most of the sectional views the illustration of the micro structure and of the marking of the marking element has been dispensed with for clarity reasons. The drawings are only to scale if this is explicitly mentioned in the description.

[0051] The drawings schematically show:

Figure 1: In two partial representations general constructions of heat shields with micro- structured outer layer;

Figure 2: Two top-views of heat shields according to the invention in the take-up area as well as a corresponding sectional view;

Figure 3: A cross-sectional view through a further embodiment of a heat shield according to the invention in the take-up area and its environment;

Figure 4: A top-view to a heat shield according to the invention as well as two corresponding cross-sections;

Figure 5: Cross-sections through two further embodiments of heat shields according to the invention;

Figure 6: Two oblique views as well as two cross-sections through a further embodiment of a heat shield according to the invention in the installed state;

Figure 7: A top-view to a further embodiment of a heat shield according to the invention in the take-up area;

Figure 8: Cross-sectional views of the take-up area of two heat shields according to the invention;

Figure 9: Two cross-sectional views of a take-up area of a further embodiment of a heat shield according to the invention with the cross-sections being oriented orthogonal one to the other;

Figures 10 Top-views and sectional views of sections of various embodiments of heat shields to 17: according to the invention;

Figure 18: Sectional views of heat shields according to the invention having different

construction with respect to their layers; and

Figure 19: A top-view of a heat shield according to the state of the art.

[0052] Figure 1-a shows a section of a top-view of a heat shield 1 according to the invention with a micro-structured layer 2, with the micro structure of the layer 2 being a micro perforation with a regular pattern, which extends over the entire heat shield 1. The heat shield comprises a second layer 3, which is dimpled. In the section shown, one can further identify two passage openings 5 for the passage of fastening means. The marking element according to the invention is not visible in the section shown, as it is attached to the side of the heat shield pointing away from the spectator.

[0053] In Figure 1-b, a heat shield 1 is shown which consists in two half-shells, which each comprise a fiber-based layer 4a, 4b and a micro-structured metallic layer 2a, 2b. Figure 1-b shows the individual parts together with the part to be shielded, 50, a catalyst. All parts are shown in an exploded view. The metallic layer 2a, 2b with its regular micro structuring 29, to be more precise with a micro perforation, in both cases forms the outer side of the heat shield, the fiber-based layer 4a, 4b forms the inner side; it comes to rest directly on the catalyst 50. Only the inlet and outlet sides of the catalyst are not covered by the fiber-based layer, but only by the micro-perforated metallic layer. The inlet and outlet passages are kept free in both layers. Here, the marking element 11 according to the invention is applied to the first micro-structured layer 2a as will be described in the following.

[0054] It is obvious from figures 1-a and 1-b that given the complete micro structuring on the surface of the heat shield, it is not possible to immediately apply any readable marking to the micro- structured surface of such heat shields but has to be realized using a separate marking element, which further needs to be permanently fastened to the heat shield or be taken up by the heat shield over the lifetime of the heat shield. [0055] Figure 2-a illustrates a cross-section through a take-up area 70 of a two-layered heat shield 1. The outer surface 61 of the heat shield is formed by a dimpled steel layer 2, the dimpling makes it possible to use a thinner steel sheet than would be the case with a non-structured metal sheet. Below the dimpled steel layer 2, a glass-fiber based insulating layer 4 is arranged which at the same time forms the inner surface 62 of the heat shield 1, with which the heat shield immediately rests on the surface of the object to be shielded 50, which may be an exhaust pipe.

[0056] In the take-up area 70, a marking element 11 lies between the dimpled layer 2 and the insulating layer 4. The insulating layer 4 shows a recess 41, where the marking element 11 is taken up at least in sections. The steel layer 2 is provided with a clearance 71 in the take-up area 70, where a section is cut-out from the steel layer. The marking field 80 of the marking element 11 here lies in the area of the clearance 71. The edges around the clearance 71 in sections are deformed as protrusions 72 downwardly, in the direction of the insulating layer 4; in the steepest section of the flank, the angle to the plane of the layer 2 in the area immediately bordering to the take-up area 70 range between 85° and 90°, in the further course in the direction of the clearance, the angle reduces again and approximates 0°. The edges of the marking element 11 at least in sections form projections 81, which point towards the outer surface 61 of the heat shield 1 upwardly. Here, a steady increase of the angle towards the plane of the marking field to nearly 90° can be identified. The protrusions 72 and the projections 81 here are adapted to each with respect to their magnitude and bending that the protrusions 72 cover the projections 81 at least in sections and this way press them downwardly against the edge 42 of the recess 41, although the exploded view of Figure 2-a does not reflect the immediate contact of the elements.

[0057] Figures 2-b and 2-c illustrate opportunities for the design of the protrusions 72. They may for instance be formed on all outer edges of the clearance 71 in sections, as is exemplified in Figure 2-b or along the entire length of the outer edge along two opposite outer edges, as is shown in Figure 2- c. It is essential that the protrusions 72 are arranged in such a way that they cover the projections 81 at least in sections and this way form a positive fit. To this end, it is preferred that the protrusions 72 are arranged in such a way that they prevent a shifting of the micro-structured layers relative to the marking element 11. A release or loosening of the layers 2, 4 and therewith also of the marking element 11 here is avoided by the fastening of the layers 2, 4 at each other or at the part 50, which is anyway required but not depicted in Figures 2-b and 2-c. The projections 81 may be formed as short lugs comparable to the protrusions 72 in Figure 2-b, or, as in Figure 2-c, extend along at least one, preferably along at least two outer edges of the marking element 11. A complete encircling is possible, too, but the corner areas then need to be deformed and left free in order to avoid disturbing concentrations of material. [0058] In Figure 2-b both the clearance 71 and the marking element 11 - apart from the protrusions 72 and the projections 81 - are essentially rectangular. In Figure 2-c, additional hexagonal embossments 75 are provided in the protruding sections of the take-up area 70 of the micro- structured layer 2, the marking element 11 is accordingly cut-out in this area. This ascertains, that the marking element 11 can only be installed in this installation position at the heat shield 1 and that the marking 19, which here has already been applied by laser therefore always shows the intended orientation. The marking field 80 of the marking element 11 in Figure 2-b is yet without any marking as this shall only be applied during the installation of the heat shield 1, e.g. using engraving by needles.

[0059] Figure 3 shows a section through a further embodiment of a take-up area 70 of a heat shield

1 according to the invention. Here, the insulating layer 4 passes through the take-up area 70 without any recess. The take-up area 70 of the micro-structured layer 2 in addition to the protrusions 72 comprises crankings 73, which are provided on the side of the protrusions 72 remote from the clearance 71. The protrusions 72 and the crankings 73 thus form groove-like reception spaces for the projections 81 of the marking element 11. Providing a combination of projections 81 and groove-like reception spaces on both sides of the cross section and therefore on two opposite sides of the take- up area 70 together with the position of the marking element 11 between the micro-structured layer

2 and the insulating layer 4, which are connected to each other outside of the section shown, results in a positive connection of the marking element 11 with the micro-structured layer 2.

[0060] Figure 4 illustrates a further embodiment of a heat shield 1 according to the invention, where the positive fit is immediately achieved between the micro-structured layer 2 and the marking element 11 arranged below the former. To this end, two passage openings 74 are provided in the micro-structured layer on each of both lateral edges of the take-up area 70, with the projections 81 of the marking element 11 being fed upwards from below through the passage openings 74. The free edges of the projections 81, which exceed beyond the upper edge of the passage openings 74, here are folded in the direction of the clearance and therefore are situated on the edge section of the micro-structured layer 2 between the passage opening 74 and the clearance 71. The projections 81, which in Figure 4-a reach through the passage openings 74 situated in the upper part of the figure, here show a larger length than the ones of the passage openings 74 situated in the lower part of the figure.

[0061] This becomes obvious, too, in a comparison of the cross-sections of Figures 4-b and 4-c, which extend along lines A-A and B-B of Figure 4-a, respectively. In Figure 4-b the folded-over sections 82 of the projections 81 do not reach to the edge of the clearance 71, while they exceed beyond this edge in Figure 4-c. With such long projections 81, it is possible to further bend the free edge, so that it does not rest freely accessible on the surface but points backwards to the clearance 71 along the edge of the clearance 71. This bending further improves the connection between the marking element 11 and the micro-structured layer 2. As in the embodiment in Figure 2-a, a recess 41 is formed into the insulating layer 4, too, where the non-deformed section of the marking element 11 is taken up. The recess is for instance embossed into the insulating layer 4. The thickness of the insulating layer 4 in the area of the recess is D4', in the area outside of the recess, namely in the areas adjoining to the recess, it is D4. This way, an additional increase of the thickness by the marking element 11 is minimized.

[0062] The embodiment of Figure 5-a differs from the preceding one in the design of the recess in the insulation layer 4 and in the reshaping of the free edge of the projection 81. The insulating layer 4 here is formed from two layers 4a, 4b, the recess 41 for the take-up of the marking element 11 results from a clearance in layer 4a. As in Figure 4, the projections 81 of the marking element 11 are guided upwards through passage openings 74. Here, the free edges are however not folded-over, but compressed like buttons, so that they form broadened areas 84, which laterally extend beyond the edges of the passage opening 74 - at least over one edge, but in the example given over both edges of the passage opening 74. If the passage openings 74 in their extension transverse to the plane of the drawing are only slightly larger than the projections 81, then the broadenings can also protrude to all sides of the passage opening and close the latter completely to the upward.

[0063] Figure 5-b is based on a one-layered insulating layer 4 where the micro-structured layer 2 in the take-up area 70 shows a constant thickness of the layer. As in Figures 4 and 5-a, the projections 81 of the marking element 11 are fed upwardly through the passage openings 74. Here, the protruding section of the projections 81 however shows an internal, almost bottom-hole like slit 84c, which in the left half of Figure 5-b is shown in a half-compressed state of the projection 81. With a further compression of the free end of the projection, the two sections 84a, 84b of the free end, which are separated by a slit 84c, are compressed in such a way that they put themselves in different directions over the passage opening 74, so that in the fully compressed state two alternate overlaps 84 results, which in a top-view correspond to filled first and third or second and fourth fields of a Cartesian coordinate system. With this, a positive connection is achieved, too.

[0064] Figure 6 in four partial drawings illustrates the shielding of one side of a part 50 by means of a heat shield 1 according to the invention, Figure 6-c corresponds to a sectional view along line C-C of Figure 6-b. Figure 6-d represents another embodiment of the invention at a comparable sectional line. This heat shield 1 is attached to the respective side of the part 50 and shields adjacent parts from the heat produced in the part 50. It becomes obvious from Figure 6-a that markings on micro- structured surfaces, here a dimpled surface, are not readable. It is even difficult to identify the connecting lines of the reference numbers. Instead, the marking - here not with a data-matrix code but with letters and numbers, is realized on a separate marking element 11, which is taken up in the take-up area 70 of the heat shield 1 between the dimpled layer 2 and the insulating layer 4. Figures 6-a and 6-b represent the same object from the same perspective with the difference that the micro structure 29 is only shown in Figure 6-a, not in Figure 6-b. As in the preceding embodiments, a clearance 71 is cut free in the dimpled layer 2, which leaves the marking field 80 free. The marking element 11 apart from the actual marking field 80 comprises two projections pointing in the direction of the insulating layer 4, which pass over into the lateral appendices 85. These appendices 85 are covered by lateral sections of the take-up area 70 which encircle the clearance 71 and this way are pressed against the recess 41 in the insulating layer 4. In addition, the layers - as is not uncommon in heat shields which immediately and completely surround the heat-emitting object - are fasted to each other by clip-like fastening means 88. Here, these clip-like fastening means 88 also reach through the appendices 85 of the marking element 11 and additionally fix the marking element 11 at the layers 2 and 4. This way, passage openings 87 and 89 are formed by the tips of the fastening elements 88 in the dimpled layer 2 and in the marking element 11 when the clip-like fastening elements 88 are inserted; the insertion of the clip-like fastening elements 88 into the insulating layer, forms blind holes. Comparable clip-like fastening elements 88 can also be identified in Figure 6-b in the area of the heat shield 1 remote from the marking element 11.

[0065] A variation of the embodiment depicted in Figure 6-c results when the free space 86 between the straight area of the marking element 11 comprising the marking field 80 on the upper side, both projections 81 on the lateral sides and the upper side of the insulating layer 4 on the lower side is filled by the insulating layer 4. In the actual embodiment shown in Figure 6-c, an individual recess 41 of the insulating layer 4 is provided for each of the appendices 85 of the projections 81.

[0066] Figure 6-d varies the embodiment in such a way that instead of inserted clips such clips 88 are used which at their free edge are bent and this way form barbed hooks. In order to realize this bending, the insulating layer 4 in the area of the clips is provided with bosses 48, where the thickness of the layer of the insulating layer 4 is also reduced. This way, an interspace forms between the insulating layer 4 and the part 50 situated below it. The marking element 11 is not immediately passed by the clips, but the bosses 48 of the insulating layer 4 pass through the recesses 99 in the appendices 85 of the marking element 11 and this way realize an indirect positive fit. [0067] It becomes clear from Figure 7 that the marking element 11 can also be used in order to connect two sections of a heat shield 1, in particular two sections 2a and 2b of the micro-structured, here micro-perforated, metal sheet 2 situated on the outer surface 61 of the heat shield 1. Two clearance sections 71a, 71b together with the adjoining areas form the take-up area 70. The two clearance sections 71a, 71b are each obtained by a cut-out starting at the sectional edges 91a, 91b reaching further into the sections 2a, 2b. The actual connection can be realized like in the embodiment of Figure 4-a, so that two projections 81 at opposite edges of the marking element 11 each reach over the outer edge of the take-up area 70. The two sections 2a 2b of the layer 2 are kept together along connecting line 90 as an effect of the plastic reshaping of the projections 81 and the support by the recess 41 in the insulating layer 4.

[0068] In Figure 8, two variants of the heat shield 1 according to the invention are illustrated which each have a micro-perforated outer layer 2 and a dimpled inner layer 3. Sound waves can enter through the openings of the micro perforation 29 into the inner space of the heat shield 1, in particular to the chambers between the dimples 39 and may run out in this inner space. The recess 41 in the additional layer of the heat shield 1, here the dimpled layer 3, can be embossed in such a way that the dimpling continues on the lower side of the marking element 11, as is shown in Figure

8- a. From a production point of view, it is however advantageous to emboss the entire take-up area 70 in the dimpled layer 3 in such a manner that it on the one hand forms a recess 41 and on the other hand forms a smooth support for the marking element 11, as is shown in Figure 8-b. Fastening of the marking element in Figure 8-a is realized comparable to Figure 4-c, the free edge 83 of the projection is however not only bent over along the edge of the clearance 71 in the direction of the marking field 80, but compressed in such a way that its free edge rests on the surface of the marking field and extends parallel to the plane of the latter. In contrast, in Figure 8-b the folding-over of the sections of the projections 81 protruding beyond the passage openings 74 is done outwardly, thus in the direction pointing away from the clearance 71. The folded-over sections come to lie on the surface of the micro-perforated layer 2. Compared to the micro-perforations, the passage openings are considerably larger, in particular larger than one would derive from the relative sizes in Figure 8. In particular the passage openings 74 show a width that is somewhat larger than the thickness of the material of the marking element 11 or its projections 81.

[0069] The embodiment of Figure 9 is very similar to the cross section shown in Figure 2-a. Here, the micro-structured layer 2 is however micro-perforated, the protrusions 72 are significantly longer than in Figure 2-a and the free edges of the projections 81 are tapered in the cross sectional view. Figure

9- b illustrates the function of this tapering in a further cross section through the marking element 11 and the micro-perforated layer 2, which extends orthogonal to the one of Figure 9-a through the section Y. Here it becomes clear that the elongate projection 81 on its upper side shows an undulated edge, the wave crests 13 - comparable to rounded serrated edges - of which merge into the micro perforations 29. To this end, the period length of the undulating edge is adapted to the distances of the micro perforations 29; every second wave crest here hooks into a perforation. It is of course possible to provide a smaller number of wave periods, where each of the wave crests merges into a micro perforation 29. It is also possible to provide a smaller number of wave crests than micro perforations 29.

[0070] A comparable merging of the undulating or serrated tips of the projections 81 into the recesses of the dimpled metal sheet is possible, but not explicitly shown. With thermoplastic edges of the marking element, a melting of edge sections is possible, too, where the molten material then flows into the micro structure and forms the connection while solidifying.

[0071] Figure 10-a shows a sectional cross-section through a heat shield 1 according to the invention which comprises two metallic layers 2, 3. A representation of the micro structuring of the layer 2 has been desisted from for clarity reasons. The layer 3 is realized as a layer from non- structured metal. In the section shown, the heat shield 1 with its two layers 2, 3 forms a pot-like recess 18, so that in both layers 2, 3, stopping walls 20, 30 are formed. The marking element 11 consists in a metallic disk from spring steel and is clamped between the stopping walls 20 of the upper, micro-structured layer 2 of the heat shield 1. The marking element 11 here shows an arc- shaped cross-section. With this positive and frictional connection between the marking element 11 and the micro-structured layer 2 of the heat shield 1, it is particularly preferred if the clamping also includes the micro structure. Thus, that the outer edge 12 of the marking element 11 also hooks into the dimples or perforations.

[0072] In Figure 10-b, a detail of the heat shield given in Figure 10-a is given in a top view. The heat shield layer 2 which lies on top is visible with its micro structure 29, namely a dimpling. The micro structures are shown with a different structure 29' in the area of the pot-like recess 18 in order to underline the skewing, stretching and/or compressing of the pattern of the dimples in the reshaped area of the pot-like recess 18. The marking element 11 here is shown without any marking and apart from its arcuate shape shows a smooth surface. In this top-view, it becomes clear that the outer edges 12 of the marking element 11, which come to rest against the stopping walls 20 are not realized as a smooth line but rather comprise serrated projections 13, which facilitate both the insertion of the marking element 11 and its fastening. In contrast, the outer edges 15 of the marking element 11, which extend transverse to the stopping walls 20 are designed smooth and also do not require any further stopping element, as the marking element 11 is permanently and securely fastened at the heat shield 1 by the clamping.

[0073] In a cross-section and in a top-view, Figures 11-a and 11-b show a heat shield with a marking element from plastics, which again on two of its outer edges shows a serrated outer edge. Due to the choice of material, this marking element 11 has a smaller resiliency than the marking element produced from spring steel in the preceding embodiment. In order to nevertheless achieve a sufficient and permanent fastening of the marking element 11 at the heat shield 1, the marking element 11 here is pressed with sufficient force into the pot-like recess 18. The serrated outer edge areas 13 hook into the stopping wall and bend from the basic plane 16 of the marking element 11. This way, they form the bending line 17. The heat shield 1 itself here is formed from a single micro- structured metal layer 2.

[0074] Figure 11-c shows another embodiment of the invention. Here, the heat shield comprises a micro-structured metallic layer 2, namely a micro-perforated layer, and an insulating layer 4 based on an impregnated fiber material with a recess 41 in the area where the pot-like recess 18 with the marking element 11 has been taken up. As in the embodiment in Figures 11-a and 11-b, the marking element is from a plastic material, namely a polyamide. Here, the tips 13' of the outer edge areas 12 have been heated up and the molten material has entered into the micro perforations. This way, the marking element 11 got connected to the micro-perforated layer 2.

[0075] In the embodiment in Figure 12, the marking element has already been placed on the single micro-structured layer 2 of the heat shield 1, before the micro-structured layer 2 has been reshaped three-dimensionally. During the three-dimensional forming of the heat shield 1, both the pot-like recess 18 has been formed and the marking element 11 has been integrated into the pot-like recess 18 and caulked with the stopping wall 20. The marking element 11 again shows two outer edges 12 with serrated projections 13, which allow to realizing the caulking. The top-view also shows the marking 19 of the marking element 11, which here is realized as a data-matrix code. The essentially round recess 18 compared to the preceding embodiments provides the advantage that a rotationally symmetric marking element can be inserted without having to care for its rotational position.

[0076] Figure 13 illustrates an embodiment of the invention with a one-layered heat shield 1 and a rectangular marking element 11. The marking element 11 again shows a data-matrix code as its marking 19, which has been engraved with needles. The stopping wall 20 of the pot-like recess 18 here is realized with a setback 23 and a projection 22 arranged above the setback 23. The outer edge 12 of the marking element 11 is taken up in the setback 23 and in its peripheral area 14 is overlapped by the projection 22. The fastening is positive, so that the marking element 11 cannot release from the heat shield 1.

[0077] The embodiment shown in Figure 14 shows a three-layered heat shield 1 with two outer metallic layers 2, 3 and a particle-based insulation layer 4 arranged between the metallic layers 2, 3. As in the example in Figure 13, the stopping wall 20 of the pot-like recess 18 forms a setback 23 as well as a projection 22 above it. The stopping wall 20 is not only formed by the micro-structured layer 2, but both other layers 3, 4 follow this shape, too. The already marked marking element 11 is taken up between the setback 23 and the projection 22. Here, the peripheral area 14 is clamped by the projection, so that a positive connection results and the arc-shaped marking element 11 made from spring steel is kept under tension between the stopping walls 20, so that its outer edges 12 press against the stopping wall 20 and additional provide for a frictional connection.

[0078] Figure 15 finally shows a one-layered heat shield 1, where the stopping walls hardly show any vertical fraction, but extend essentially s-shaped. Here, the micro-structured layer 2 is bent back on itself. The marking element 11 immediately rests on the section 24 of the layer 2 and on the upper side of its peripheral areas 14 is overlapped by the folded-over projections 22a, 22b of the micro-structured layer 2. The projections here are folded-over in such a way that the distance between the lower side of the projections and the upper side of the section 24 exactly corresponds to the thickness of the marking element 11 or is slightly smaller so that the marking element 11 is held positively and frictionally. The outer edges here lie freely in the areas of the folding 23, which are set back.

[0079] Figure 16 shows a modification of the embodiment given in Figure 11 in a cross-sectional view. However, here the marking element 11 is made from a spring steel. Compared to the variant given in Figures 11-a and 11-b, this embodiment lends itself especially for such situations where a recess 18 with only little depth is available or where the recess 18 is located at a position which is difficult to access. Here, the marking element 11 with bending edges 17 can much easier hook into the wall 20 than was the case for the smoothly rounded marking element 11 given in Figure 10.

[0080] In Figure 17, a variation of the multi-layered heat shield given in Figure 14 is shown in the cross-sectional view. Here, the recess 18 is only formed in the layer 2, while the other layers 3, 4 leave out the area of the recess. The non-metallic layer 4 here is formed from a temperature-stable paper, so that the free edges of this layer 4 at the edge of the recess cause no drawback.

[0081] Figure 18 shows exemplary constructions of multi-layered heat shields 2 according to the invention. In the embodiment given in Figure 18-a, the heat shield 1 consists in a micro-perforated layer 2 as well as a layer 3 from a formed thermoset, which is not realized as a smooth layer, but as a layer with small posts 33. The small posts here span the resonance chambers 34, so that a good sound absorption becomes possible. The embodiment of Figure 18-b combines a micro-perforated outer layer 2 with a package of dimpled layers 3. With the example of Figure 18-b it also becomes obvious that several formation steps are required during the production of a heat shield, such as the folding-over of the hem 7 at the outer edge around the other layers which results in the interconnection of all layers. This underlines that the positive and/or frictional fastening of the marking element 11 at the heat shield 1 usually does not require any additional production steps. Figure 18-c finally combines a dimpled metal sheet 2 with a micro-perforated metal sheet 3. The pattern of the dimpling is about the 5-fold larger than the micro perforation in the example shown.

[0082] Figure 19 illustrates that the direct application of a marking 119 to a conventional heat shield with a non-structured metal layer as outer layer 102 can be realized without difficulty. At the same time, one can easily imagine that a corresponding direct application of a marking to a heat shield with a micro-structured outer layer does not lead to a readable marking and especially not to a machine-readable marking.

Claims

Heat shield (1) for shielding of an object against heat and/or sound with at least one metallic layer (2,

3), with at least one metallic layer (2) situated at a surface of the heat shield (1) comprises a micro structuring (29),

characterized in that

a laminar marking element (11) is applied to the surface and/or embedded into the at least one micro-structured layer (2), with the laminar marking element (11) being positively and/or frictionally connected to the at least one micro-structured layer (2) of the heat shield (1).

Heat shield (1) according to the preceding claim, characterized in that the heat shield (1) comprises at least one further layer (3, 4), with the at least one micro-structured layer (2) being situated at an outer surface (61) of the heat shield (1) and the at least one further layer (3, 4) being preferably situated at an inner surface (62) of the heat shield (1).

Heat shield (1) according to one of claims 2 or 3, characterized in that the laminar marking element (11) is arranged on the surface of the at least one micro-structured layer (2) pointing away from the outer surface (61) of the heat shield (1) between the at least one micro-structured layer (2) and the at least one further layer (3,

4).

Heat shield (1) according to one of the preceding claims, characterized in that the at least one micro-structured layer (2) comprises one take-up area (70), in which take-up area (70) the micro-structured layer (2) comprises at least one clearance (71), with the take-up area (70) comprising one or several passage openings (74) or at least sectional recesses adjacent to the clearance (71), with the protrusions (72) pointing from the outer surface (61) of the heat shield (1) towards an inner surface (62) of the heat shield (1).

5. Heat shield (1) according to the preceding claim, characterized in that the laminar marking element (11), preferably at its outer edge, at least in sections comprises a projection (81), with the at least one projection (81) pointing in the direction of the outer surface (61) of the heat shield (1) when the laminar marking element (11) is arranged between the at least one micro- structured layer (2) and the at least one further layer (3, 4), with the at least one projection (81) being arranged in such a manner that it

- is situated between a protrusion (72) of the take-up area of the at least one micro-structured layer (2) and the at least one further layer (3, 4) and/or

- extends through the at least one passage opening (74) and is preferably deformed and/or compressed on the outer surface (61) of the heat shield (1), with the at least one micro-structured layer (2) comprising preferably comprising a cranking (73) adjacent to at least one protrusion (72) of the take-up area (70), with the cranking being preferably arranged on the side of the protrusion (72) pointing away from the clearance (71) and with the at least one projection (81) of the marking element (11) being preferably arranged between the protrusion (72) and the cranking (73).

6. Heat shield (1) according to the preceding claim, characterized in that the at least one further layer (3, 4) in the area of the take-up area (70) of the at least one micro-structured layer (2) comprises at least in sections at least one recess (41) with the at least one projection (81) of the laminar marking element (11) being preferably arranged between at least one protrusion (72) of the take-up area (70) of the at least one micro-structured layer (2) and at least one edge (42) of the at least one recess (41) of the at least one further layer (3, 4). Heat shield (1) according to the preceding claim, characterized in that the at least one further layer (3, 4) is

- a structured or non-structured metallic layer (3) with the thickness of the layer (D3') of the at least one further layer in the area of the at least one recess (41) being essentially identical with the thickness of the layer (D3) of the at least one further layer (3, 4) outside of the at least one recess (41) and/or an insulating layer (4) with the thickness of the layer (D4') of the insulating layer (4) in the area of the at least one recess (41) is reduced compared with the thickness of the layer (D4) of the insulation layer (4) outside of the at least one recess (41).

Heat shield (1) according to one of the preceding claims, characterized in that the heat shield (1) has a closed shape with at least one connecting line (90) at which two edge sections (91a, 91b) of two sections (21, 2b) of the at least one micro-structured layer (2) contact each other at least in sections, with the take-up area (70) being situated in the area of the at least one connecting line (90), with the marking element (11) preferably connecting the two edge sections (91a, 91b) of the at least one micro-structured layer (2) positively and/or frictionally.

Heat shield (1) according to one of the preceding claims, characterized in that the heat shield (1) comprises at least two layers (2, 3, 4) with the layers being connected to each other using at least one fastening element, preferably a clip or a brace, where the at least one fastening element is fastened to the heat shield layers (2, 3, 4) in such a way that it passes through the laminar marking element (11). Heat shield (1) according to one of claims 1 to 3, characterized in that the at least one micro-structured layer (2) comprises a local immersion (18) with the marking element (11) being received in the immersion (18), with the local immersion (18) at least in one laminar dimension showing a slightly reduced extension compared to the marking element (11) in the same laminar dimension.

Heat shield (1) according to one of claims 1 to 3 or 10, characterized in that at least the at least one micro-structured layer (2) of the heat shield (1) or the entire heat shield (1) comprise at least two sections (22a, 22b), in which the at least one micro-structured layer (2) or the entire heat shield is folded back onto itself while clamping the marking element

(11) between the layer and the fold-back section.

12. Heat shield (1) according to the preceding claim, characterized in that at least two peripheral sections (12) of the marking element (11) are clamped on an upper and a bottom side by the micro-structured layer (2) where each time the peripheral sections (12) of the marking element (11) and both sections (22a, 22b) of the micro-structured layer (2) preferably resting immediately one on the other at least in sections.

13. Heat shield (1) according to one of claims 2, 3 or 10 to 12, characterized in that the at least one further layer (3, 4) comprises a thermoplastic or a ther- moset plastic with or without metallic coating or lamination or consists in such.

Heat shield (1) according to one of claims 2 to 13, characterized in that the at least one further layer (3, 4) is an insulating layer and comprises or consists of a woven material, interlaced yarns, a crocheted material, a knitted material, a fiber roving or a fleece, preferably from mineral fibers, glass fibers, carbon fibers and/or composite fibers with or without impregnation and/or a chemical modification of such or temperature-stable fiber material or comprises compacted mineral particles or consists of such.

15. Heat shield (1) according to one of the preceding claims, characterized in that the heat shield comprises at least two passage openings for fastening means (5).

16. Heat shield (1) according to one of the preceding claims, characterized in that the laminar marking element (11) comprises a non-structured surface.

17. Heat shield (1) according to one of claims 1 to 15, characterized in that the laminar marking element (11) comprises an inscription (19) with the inscription (19) being preferably applied and/or introduced by

- laser and/or

- a printing method, in particular by ink jet printing and/or

- a coining method and/or

- a punching method and/or

- engraving, preferably with needles and/or

- etching.

18. Heat shield (1) according to one of the preceding claims, characterized in that the marking element (11) consists in steel, in particular steel or in an aluminum alloy or comprises metal, in particular steel or an aluminum alloy.

19. Heat shield (1) according to one of claims 1 to 17, characterized in that the marking element (11) consists in a thermoplastic or thermoset material or comprises a thermoplastic or thermoplastic material.

20. Heat shield (1) according to one of the preceding claims, characterized in that the material of the at least one micro-structured layer (2) is selected from an aluminum alloy or a steel, on particular a coated steel, in particular a fire- aluminated or aluminum-plated steel or in a stainless steel.

21. Heat shield (1) according to one of the preceding claims, characterized in that the micro structuring (29) is a dimpling where

- the height of at least one dimple is between 0.8 and 20 mm, preferably between 1 and 15 mm, particularly preferably between 3 and 10 mm and/or

- the diameter of at least one dimple is between 1 and 20 mm, preferable between 3 and 10 mm and/or

- the surface area of at least one dimple is between 3 and 500 mm², preferably between 10 and 70 mm² and/or

- the angle of a flank of at least one dimple is between 20 and 90 °, preferably between 30 and 60 ° and/or

- the distance of the crests of the dimples is between 2.5 and 30 mm, preferably between 6 and 15 mm and/or

- the density of the dimples is between 1 and 10, preferably between 1 and 6 dimples per square centimeter.

22. Heat shield (1) according to one of the preceding claims, characterized in that the micro structuring (29) is a micro perforation where in particular

- the diameter of at least one micro perforation is between 0.05 and 3 mm, preferably between 0.08 and 1 mm and/or

- the density of the micro perforations is between 1 and 200, preferably between 3 and 100 holes per square centimeter and/or

- the area that is taken by the holes ranges between 0.1 % and 20%, in particular between 0.2 and 10% of the total area of the micro-structured layer (2).