EP2668386A2

EP2668386A2 - Heat shield

Info

Publication number: EP2668386A2
Application number: EP11805427.9A
Authority: EP
Inventors: Axel Ritzal; Franz Schweiggart
Original assignee: Reinz Dichtungs GmbH
Current assignee: Reinz Dichtungs GmbH
Priority date: 2011-01-26
Filing date: 2011-12-29
Publication date: 2013-12-04
Also published as: WO2012100808A3; CN103339358B; DE202011001961U1; KR20140010051A; KR101587151B1; WO2012100808A2; CN103339358A

Abstract

The present invention relates to a heat shield (1) for shielding of hot areas, e.g. in a combustion engine, with at least one metal sheet layer (2), with the at least one metal sheet layer (2) comprising at least one passage opening (3) for taking-up a fastening means (5), and with at least one decoupling element (10) being arranged in at least one of the pas- sage openings (3) for at least partially decoupling or dampening the transfer of vibrations or heat from the at least one metal sheet layer (2) to the fastening means. Therein at least one of the at least one metal sheet layer (2) adjacent to the peripheral edge of the at least one passage opening (3) comprises at least one hole (6) and that the decoupling element (10) comprises at least one retainer element (14) being arranged on a first surface of the heat shield (1) radially outside the outer edge of the passage opening (3), which rests on one of the metal sheet layers (2) as well as at least one clamping element (16) arranged radially outside the outer edge of the passage opening (3), which at least one clamping element passes via the hole (6) through at least one of the metal sheet layers (2) and clamps behind at least one of these metal sheet layers (2).

Description

Heat shield

The present invention relates to a heat shield, which is used for shielding hot areas, e.g. of a combustion engine. Such heat shields, conventionally comprise at least one metal sheet layer. This metal sheet layer reduces the emission of heat emitted from a source of heat from its hot side facing the hot area to its cold side pointing away from the hot area and therefore reduces heat transfer. Further, such a heat shield does not only provide a reduction of the transfer of heat from the hot to the cold surface of the heat shield but also dampens the transfer of vibrations from one side of the heat shield to the other side.

In other embodiments, such heat shields comprise at least two metal sheets, which are connected to each other at least in sections, e.g. along their outer edge. Such a connection can for instance be achieved by folding the edge of one layer around the edge of the other one forming a kind of hem. The two sheet layers this way form a housing, in which further intermediate layers, such as soft materials, paper, fi- bre fleece but also mica, expanded mica, graphite or expanded graphite - either as particles or as a pressed piece, a so-called filet - may be incorporated.

Conventionally, such heat shields or their metal sheets comprise bores as passage openings, which reach through the at least one metal sheet. These bores when installed may take up fastening means, such as screws, which enables fastening of the heat shield at or in a combustion engine.

These fastening means usually are attached to the corresponding part, e.g. a combustion engine. This makes it possible that the fastening means transfer both vibrations and heat from the part to the heat shield. As a consequence, various decoupling elements have already been presented for decoupling transfer of heat and vibration from the fastening means to the heat shield. Wire cushions made from knitted wire and the like are widely used as decoupling elements.

Such wire knittings on the one hand are very expensive and on the other hand have a considerable weight, which is ob ectionable with light-metal heat shields.

It is further disadvantageous that mounting of such decoupling elements is cumbersome, as they have to be installed from both sides of the heat shield. Moreo- ver, it is necessary to stock the decoupling elements in addition to the heat shields and the fastening means and to provide the mechanic separately with all of them at the mounting site.

Mounting of such decoupling elements is a further challenge for the mechanic.

It is therefore the object of the present invention to provide a heat shield with a cost-efficient, light-weighted and easy to install decoupling element, which insulates the heat shield with respect to heat and/or vibrations. Further essential objects of the present invention are long-term stability and economic efficiency.

This object is solved by a heat shield according to claim 1. Advantageous embodiments are given in the dependent claims .

The heat shield according to the invention is mainly suited for applications in combustion engines as well as their ancillary units. It is especially advantageous to design light-metal heat shields, such as aluminium heat shields according to the present invention.

The heat shield according to the invention can be installed in a rapid and simple manner. This also allows for limiting the mounting costs. Depending on the practical case, one can choose between embodiments with the decoupling element being pre-mounted on the heat shield or with the decoupling element to be inserted during installation of the heat shield. Heat shields according to the invention with pre- mounted decoupling elements are especially advantageous as they allow for an installation of the heat shield without inserting additional parts, without deformation of any elements etc. and with extremely- short cycle times.

The heat shield according to the invention comprises at least one metallic sheet layer with at least one passage opening for a fastening means. According to the invention, a decoupling element is inserted to this passage opening. The decoupling element enables at least a partial decoupling or dampening of the transfer of heat and vibrations from the fastening means to the heat shield. To do so, the decoupling element comprises retainer elements and clamping elements . The retainer elements come to rest on one side of the at least one metal sheet of the heat shield. To this end, the retainer elements need to be situated outside the area of the passage opening for the fastening means, thus in the area of the metal sheet. The decoupling element further comprises clamping elements, which pass through holes in the metal sheet and come to rest on the opposite surface of said metal sheet or in case they pass through holes in more than one metal sheet layer, come to rest on the opposite side of the most remote one of said more than one metal sheet layers .

These holes are as well situated outside the area of the passage opening for the fastening means. Starting from the surface, on which the retainer elements are situated, the clamping elements reach through the holes in one, several or all of the metal sheet (s) to the opposite surface of said metal sheet (s) of the heat shield through which they have passed. It is possible that they do not pass through all metal sheet (s) of the heat shield and come to rest between two neighbouring metal sheets. This causes the decoupling element to be fastened in a form-locking manner and enables a simple mounting of the decoupling element in the passage opening of the heat shield.

The retainer elements and the clamping elements may be linked to a central base element in the area of the passage opening of the decoupling element via linking elements which extend radially with respect to the passage opening. The retainer and clamping elements may thus be situated radially distanced to the central base element of the decoupling element.

The base element is advantageously arranged in the passage opening of the respective metal sheet or of the heat shield. It is especially advantageous if the base element is arranged as a disk-shaped, especially as a circular element in a concentric manner with respect to the passage opening. Preferably, it comprises an opening which can be arranged concentrically to the passage opening in the heat shield and allows for taking up a fastening means. The outside diameter of the base element may be smaller than the inner width of the passage opening of the metal sheet allowing for a complete arrangement of the base element in the area of the passage opening.

If a heat shield shows a considerably non-symmetric vibration, an off-centered arrangement, e.g. via an oblong passage opening, may be favourable. Such a non-symmetric vibration can for instance result from interactions between different fastening areas.

It is especially advantageous if the base element is arranged in the plane of the metal sheet of the heat shield in the passage opening of the metal sheet . The linking elements extending radially then may be cranked in such a way that they pass over into the retainer elements and - directly or indirectly - the clamping elements on the same surface of the metal sheet or the heat shield as such. The clamping elements then have integral crankings which allow them to reaching through holes in the metal sheet (s) or the heat shield so that the free ends of the clamping elements clamp from the opposite surface to the most remote one of the metal sheets through which it reaches through and cause a form-locking connection of the decoupling element to the metal sheet or the heat shield.

With heat shields comprising more than one layer, it can be advantageous that the clamping elements reach through all of the layers - including non-metallic layers - and their free ends come to rest on the most remote surface of the outermost layer, thus on the other surface of the heat shield. In other situations, it is advantageous if the clamping elements reach through only some of the layers - in the most extreme of cases only through one metallic layer - and their free ends come to rest on the opposite side of the most remote one of said layers which are reached through. This means that the part of the clamping element which has passed through a hole in the metallic layer may nevertheless be covered by at least one layer of the heat shield.

In order to optimize the decoupling effect or to balance out a strongly non-symmetrical vibration of the heat shield, it is advantageous to design the linking elements in an asymmetrical manner. It is for instance possible to provide different distances between different pairs of neighbouring linking elements. In the same way, the heights of the crankings may be different. Moreover, the width of the linking elements, especially in the area of the cranking may vary, e.g. the linking elements may comprise a waist.

Further, the retaining elements and the clamping elements may be arranged at different or same radial distances to the passage opening for all or only some of the retaining elements and/or all or only some of the clamping elements. They may stretch out into the same circumferential direction or in opposite circumferential directions for all or only some of the retaining elements and/or all or only some of the clamping elements. Finally, the length of the retaining elements and the clamping elements may be chosen independently for all or only some of the retaining elements and/or all or only some of the clamping elements .

The contact between the retainer and clamping elements on the one hand and the adjacent metal sheet of the heat shield on the other hand can further be improved by means of half beads (crankings) or full beads integrated in the course or at the end of the retainer and/or clamping elements. They provide for a resilient contact between the retainer and clamping elements and the respective adjacent metal sheet. At the same time, the contact area between the decoupling element on the heat shield or the part on which it is fastened is reduced, causing a reduced heat transfer.

A particular advantage of the decoupling element results from the fact that it can be installed in an especially easy manner by screwing-in, comparable to a bayonet connector. With the cranking situated at the transition between the retainer and the clamping elements, after tightening the heat shield to another part, the decoupling element cannot loosen by itself from the passage opening. This design thus provides for a particularly stable and safe connection between the decoupling element and the metal sheet (s) of the heat shield.

The invention comprises in particular two alternative embodiments: Either the fastening means is fastened to the heat shield in a loss-prove manner when mounting the decoupling element at the site of the producer of the heat shield or the decoupling element is mounted at the site of the producer of the heat shield but the fastening element is only inserted when fastening the heat shield to the neighbouring part. With the latter embodiment, it is possible to use either screws or bolts as fastening means as is already known from the state of the art.

Advantageously, the fastening means is arranged in the opening of the decoupling element in a loss-proof manner but still moveable. This can be achieved in a particularly preferred manner with a screw as the fastening means. In this way, it is no longer necessary to provide the mechanic responsible for the installation of the heat shield with separate fastening means. It further disburdens the mechanic as the fastening means is provided together with the heat shield and the decoupling element and can be fastened in a facilitated manner on the part. This embodiment also prevents from a cumbersome separate storage and disposition and further avoids the risk of using un- sui ed fastening means.

It is preferred to use screws as loss-proof fastening means . They can be supported in the passage opening in a rotatable manner. It is advantageous if the screw is additionally moveable in the passage direction of the opening. In case of a screw, the mechanic can bring the heat shield into the position for mounting without the risk of loosing the screw by falling off in the direction opposite of the part.

Thus, it can be installed immediately after it has been put into place by screwing.

According to the invention, a screw can be arranged in the opening of the decoupling element in a moveable manner if the screw has a stem which between the head of the screw and the thread has a smaller diameter than the neighbouring thread. If this area with reduced diameter has been inserted into a correspond- ing narrow passage opening in the heat shield or the decoupling element, the screw cannot fall off the passage opening by itself.

In another advantageous embodiment the screw is a threaded bolt with an offset, thus a threaded bolt with two areas of different diameters of the thread, which only after inserting the bolt to the heat shield is provided with a screw head, e.g. by screwing .

Preferably, the fastening means arranged in a loss- proof manner is arranged with a pre-tension in the direction of the screw head, e.g. by support on a spring. This way, the screw is pressed backwards, which upon adequate selection of the length of the stem of the screw provides for the screw not protruding from the passage opening of the heat shield in the direction of the part where it is to be installed. During the installation of the heat shield, this prevents the screw from protruding towards the part which would obstruct an exact positioning of the heat shield. After positioning, the screw can be fixed in the corresponding female thread in the part surmounting the pre-tension. This is especially advantageous if installation has to be performed horizontally or from above, as the spring prevents the screws from gravitationally moving in the direction of the part.

Such a spring provides for a further possibility of a loss-proof but moveable mounting of the screw in the opening. To this end, the spring can be connected both to the screw head and the opening or the decoupling element in a form-locking and/or adhesive manner. The spring presses the screw head and therefore the complete spring axially away from the metal sheet of the heat shield, but prevents the screw from falling off the passage opening.

With a two-layered or multi-layered heat shield, it is advantageous that the passage opening in the metal sheets is arranged in an area where no further intermediate layer is arranged between the metal sheets . This provides for an excellent force-locking connection of the heat shield at the part on which it is installed.

In the following, some examples of heat shields according to the invention are presented. The elements of the respective examples represent elements of the present invention not only in the context of the particular example, but also if considered alone. In the following, the same or comparable reference numbers are used throughout for the same or comparable elements .

It is shown in Figure 1 a mounted heat shield with a decoupling element according to the state of the art; Figure 2 a decoupling element according to the invention;

Figure 3 a decoupling element according to the invention mounted in a passage opening of a heat shield in a top view on a first side of a metal sheet;

Figure 4 a top view on a decoupling element according to the invention mounted in a passage opening of a heat shield;

Figure 5 a heat shield according to the invention with a fastening means inserted;

Figure 6 a further decoupling element according

the invention;

Figure 7 a further decoupling element according to the invention;

Figure 8 in two partial figures 8A and 8B further decoupling elements according to the invention; Figure 9 a further decoupling element according to the invention;

Figure 10 a top-view to another decoupling element according to the invention; and

Figure 11 a sectional view through another decoupling element installed in a heat shield according to the invention in the installed state .

Figure 1 shows a heat shield as known from the state of the art, which comprises the metal sheets 2a and 2b arranged one on another and parallel to each other. These metal sheets comprise a passage opening 3 for receiving a screw 5 as the fastening means. The screw 5 comprises a thread 8a, which in figure 1 is shown in a lateral view.

The heat shield 1 is fastened on a further part 4, e.g. an engine block, by means of the screw 5.

Between the part 4 and the heat shield 1 as well as between the heat shield 1 and the head 7 of the screw 5, a wire cusion 10a is inserted as a conventional decoupling element, which completely surrounds the passage opening 3 togehter with the sleeve 10b. The wire cusion 10a acts as a decoupling element between the screw 5 and the heat shield 1 providing that heat and vibration are not or only to a reduced extent transferred via the screw 5 to the heat shield 1.

In contrast to the conventional heat shield 1 depicted in figure 1 with a conventional decoupling element 10, figure 2 shows a decoupling element 10 according to the invention. This decoupling element 10 as a first element comprises a base element 11, which has a circular outer diameter. The base element 11 comprises an opening 20, which in the installed state of the decoupling element is arranged concentrially in the passage opening 3 of the heat shield 1 (See figure 1). In figure 2, the opening 10 has an outer edge 21 with a hexagonal shape, which allows the decou- pling element 20 to be rotated around the passage axis of the opening 20 with a hexagonal wrench.

Three radial arms 12a, 12b and 12c branch off the base element 11 - each of them being offset by 120° around the middle axis of the base element 11. They extend in a radial direction from the base element 11. At each transition from the base element 11 to an arm 12a, 12b or 12c, a cranking 13a, 13b, 13c is pro- vided. At its radial edge, each arm 12a, 12b and 12c branches off into two branches 14a and 16a, 14b and 16b, 14c and 16c, which all extend along the circumferential direction of the base element 11. The branches 14a, 14b and 14c serve as retaining arms, which mainly extend in the plane defined by the crankings 13a, 13b and 13c, thus in the plane of the radially extending arms 12a, 12b and 12c. The branches extending from the radial arms 12a, 12b and 12c in the radially opposite direction - compared to the other branches - are used as clamping elements 16a,

16b and 16c. The crankings 17a, 17b, 17c, cause the clamping elements 16a, 16b and 16c to be offset from the linking elements 12a, 12b and 12c towards the plane of the base element 11. At their free ends, they comprise a further cranking or half bead 18a,

18b, 18c, which points to the same direction as the crankings 17a, 17b, 17c, when compared to the arms 12a, 12b, 12c. In the following examples, the heat shield 1 itself is indicated as an oval object. However, a heat shield can have various shapes. The oval shape with its simple form has been merely chosen for demonstration purposes .

Figure 3 shows such a decoupling element 10 fastened to a metal sheet layer 2 of a heat shield 1. The heat shield 1 comprises three bores or slits 6a, 6b and 6c extending radially and concentrially to the passage opening 20. In figure 2, the decoupling element 10 is shown installed in the heat shield 1. To this end, the decoupling element 11 with its clamping arms 16a, 16b and 16c is positioned in a suitable position on the metal sheet layer 2 and then rotated clockwise causing the clamping arms 16a, 16b, 16c to reach through the slits 6a, 6b, 6c and engaging on the other surface of the metal sheet layer 2. This way, the decoupling element 10 is securely fastened to the metal sheet layer 2. In the example shown, the decoupling element mainly serves for thermally decoupling.

Figure 4 shows a top-view on a further heat shield 1, which comprises a decoupling element 10 comparable to the one in figure 3. In contrast to figure 2, here the outer diameter of the base element 11 is smaller than the free width of the passage opening 3 of the metal sheet layer 2. As a consequence, the base element 11 of the decoupling element 10 is distanced from the peripheral edge of the passage opening 3. This further improves the decoupling between a fas- tening means fastened in the opening 20 and the metal sheet layer 2.

In Figure 5, the same heat shield as in figure 4 is shown, however a washer 9 and a screw 5 with a screw head 7 have been positioned on the base element 11.

In this state, the heat shield 1 can be screwed to another part, with the part and the screw being decoupled from the metal sheet 2 of the heat shield 1 through the decoupling element 10 mounted in the pas- sage opening 3 both with respect to heat and vibration transfer at least to a large extent. Figure 6 shows a top view of a further decoupling element 10 comparable to the one shown in figure 2. Here as well as in the two following embodiments, one has desisted from explicitly showing the crankings

13a, 13b, 13c in the area of the linking elements

[l2a, 12b, 12c. Figure 6 mainly aims on a comparison with the two following embodiments. Figure 7 shows a top view of a further decoupling element according to the invention, now with four retaining arms 14a, 14b, 14c, 14d as well as with four clamping arms 16a, 16b, 16c, 16d.

Compared to figures 2 and 6, in this decoupling element 10, the positions of the retaining elements 14a, 14b, 14c, 14d have been interchanged with the clamping arms 16a, 16b, 16c, 16d. Besides, this decoupling element 10 is similarly designed. Only the ends of the retainer arms 14a to 14d and of the clamping arms 16a to 16d are provided with an indentation.

Figure 8 shows in figures 8A and 8B two other decoupling elements 10 comparable to the one in figure 6. However, both decoupling elements show a non- symmetric design.

In the embodiment given in figure 8A, the radial arm 12b is designed differently from the radial arms 12a and 12c. It shows both a waist and a recess 22. In this way, the arm 12b compared to the other two arms 12a and 12c is softer and more resilient. Moreover, it vibrates in a different frequence range than the arms 12a and 12c. This provides for a non-symmetric decoupling of the vibration. Further, the opening 20 here is designed as a round opening instead of a hex- agonal opening. The retaining arms 14a, 14b, 14c in the decoupling element 10 in figure 8A are additionally designed in an angled manner, which causes that they protrude into the area between the clamping arms 16a, 16b, 16c on the one hand and the base element 11 on the other hand.

The free ends 18a, 18b and 18c of the retaining arms 14a, 14b, 14c further are enlarged resulting in a contact surface of the retaining arms 14a, 14b, 14c, which on the one hand is arranged close to the opening 20 and on the other hand provides for a secure rest of these arms.

Figure 8B also shows a non-symmetric embodiment of a decoupling element 10. On the one hand, the opening 20 here is realized as an oblong hole, which allows for a non-centric insertion of the fastening means . On the other hand, the arms 12a and 12b relative to each other show a smaller distance than relative to the third arm 12c, with the length of the retainer arms 14a, 14b, 14c as well as the length of the clamping arms 16a, 16b, 16c being adapted to this and therefore having a different length. This, too, causes a non-symmetric vibrational decoupling.

Figure 9 shows a further decoupling element 2, which is designed similar to the one in figure 2. In figure 9, a screw 5 with a stem 8 is additionally arranged in the decoupling element. The stem 8 of the screw 5 is surrounded by a spring 25. This spring is closely attached to the head 7 or the collar 27 of the screw 5. In the same way, the other end of the spring is connected to the decoupling element 10. This way, the screw 5 is arranged in a loss-proof manner in the openings 3 and 20, respectively. The spring 25 is at- tached to the head 7 of the screw 5 so that it cannot loosen by itself from the screw 5, but the head of the screw 7 can be rotated relative to the spring. Therefore, it is possible to press the screw 5 against the force of the spring 25 through the passage opening 3 and consecutively to screw it into the neighbouring part. Because of the pre-tension of the spring, the head of the screw in the non-loaded state is pushed as far away from the heat shield 1 as pos- sible, so that upon suitable selection of the length of the stem 8, this stem 8 of the screw 5 does not protrude beyond the metal sheet layer 2.

This helps to avoid that during positioning at the part, the heat shield 1 is caught at protrusions or the like of this part and therefore obstructs the installation of the heat shield 1 on the part. In figure 9 the heat shield itself is not shown in order to provide for more clarity of the figure.

Figure 10 shows another embodiment of the decoupling element 2 according to the invention with rotational symmetry. Here, the retainer elements 14a, 14b, 14c constitute radial triangular appendices of the linking elements 12a, 12b and 12c, where the linking elements 12a, 12b, 12c are connected to the retainer elements 14a, 14b, 14c respectively at one tip of the triangular retainer elements 14a, 14b, 14c. A neighboring tip then stretches out into a clamping element 16a, 16b, 16c. The clamping elements 16 are designed comparable to the previous embodiments .

Figure 11 depicts the arrangement of a decoupling element 2 with a base element in a two-layered heat shield 1 having an upper layer 2a and a lower layer

2b. The sectional view apart from the heat shield layers corresponds to section A-A in Figure 10. The base element has been inserted into a passage opening 3 of the heat shield 1. However, the base element as such cannot be identified in the sectional view, the section is taken through the clamping arm 16a. The base element 11 is hidden behind this clamping element 16a. Radially distant to the passage opening and stretching circumferentially clamping arms 16a, 16b, 16c are provided which, however, pass through holes in the upper layer 2a of the heat shield 1. In fig. 11 a clamping arm 16a is depicted, which passes from the outer surface of upper layer 2a through a hole 6 in the upper layer 2a and clamps to the lower, inner surface of upper layer 2a. Thereby the clamping arm 16a is fixed between the upper layer 2a and the lower layer 2b in a sandwich-like manner. Each of the clamping arms shows a cranked terminal section 18.

Claims

Heat shield (1) for shielding of hot areas, e.g. in a combustion engine, with at least one metal sheet layer (2), with the at least one metal sheet layer (2) comprising at least one passage opening (3) for taking-up a fastening means (5), and with at least one decoupling element (10) being arranged in at least one of the passage openings (3) for at least partially decoupling or dampening the transfer of vibrations or heat from the at least one metal sheet layer (2) to the fastening means

characterized in that

at least one of the at least one metal sheet layer (2) adjacent to the peripheral edge of the at least one passage opening (3) comprises at least one hole (6) and that the decoupling element (10) comprises at least one retainer element (14) being arranged on a first surface of the heat shield (1) radially outside the outer edge of the passage opening (3), which rests on one of the metal sheet layers (2) as well as at least one clamping element (16) arranged radially outside the outer edge of the passage opening (3), which at least one clamping element passes via the hole (6) through at least one of the metal sheet layers (2) and clamps behind at least one of these metal sheet layers (2). Heat shield according to the preceding claim characterized in that the clamping element (16) protrudes beyond the outer edge of the passage opening (3) on the first surface.

Heat shield according to one of the preceding claims characterized in that the decoupling element (10) comprises a base element (11), preferably a disk-shaped, preferably a circular base element, which comprises an opening (20) concentric to the passage opening (3) for the passage of a fastening means (5) .

Heat shield according to the preceding claim characterized in that the base element (11) is arranged concentric to or concentrically in the passage opening (3).

Heat shield according to one of the two preceding claims characterized in that the outer diameter of the base element (11) is smaller than the open width of the passage opening (3) .

Heat shield according to one of claims 3 to 5, characterized in that at least one of a retainer element (14) and a clamping element (16) are situated radially distanced to the base element (11) , preferably concentrically to the passage opening (3), at the same or different radial distances for retainer elements and/or clamping elements .

Heat shield according to one of claims 3 to 5 , characterized in that at least one of a retainer element (14) and a clamping element (16) adjoin to a linking element (12) for linking the at least one of a retainer element (14) and a clamping element (16) to the base element (11) . Heat shield according to the preceding claim characterized in that the at least one linking element (12) is cranked, preferably at the transition between the base element (11) and the at least one linking element.

Heat shield according to one of the two preceding claims characterized in that at least one clamping element (16) at the transition between the clamping element (16) and the linking element (12) is cranked, preferably in a direction opposite to the cranking in the linking element (12) .

Heat shield according to one of the preceding claims characterized in that at least one of a retainer element (14) and a clamping element (16) at its free end is rounded off or cranked.

Heat shield according to one of the preceding claims characterized in that at least one of a retainer element (14) and a clamping element

(16) comprises a bead, with the head of the bead pointing towards the adjacent metal sheet layer

(2) .

Heat shield according to one of the preceding claims characterized in that the clamping element passes through one, several or all of the metal sheet layers (2) , which are arranged in one direction adjacent to the retainer element.

Heat shield according to one of the preceding claims characterized in that the decoupling element (10) is formed as a one-piece from a metal sheet . Heat shield according to one of the preceding claims characterized in that a fastening means (5) is arranged in the passage opening (3) and attached to the base element (11) of the decoupling element in at least one of a form-lock and a positive connection.

Heat shield according to the preceding claim characterized in that the fastening means (5) is arranged in the passage opening (3) in a moveable manner with respect to at least one degree of freedom.

Heat shield according to one of the preceding claims characterized in that the fastening means (5) is a screw.

Heat shield according to one of the preceding claims characterized in that a loss-proof attachment is achieved by a press fit of the fastening means (5) in the decoupling element (10) in the passage opening (3) .

Heat shield according to one of the preceding claims characterized in that the fastening means (5) is a screw with the head (7) of the screw clamped to the decoupling element (10) by a spring (25) which spring (25) is pre-tensioned, preferably in the direction of the head (7) of the screw.

Heat shield according to the preceding claim characterized in that the spring (25) on the one hand is attached to the head (7) of the screw with at least one of a force-lock and a positive fit and on the other hand is attached to at least one of the metal sheet layer (2) and the decoupling element (10) with at least one of a force-lock and a positive fit.

Heat shield according to one of the two preceding claims characterized in that the diameter of the stem of the screw (5) in the area between the thread (8) and the head (7) is smaller than the open width of the opening (20) of the decoupling element (11), and that the diameter of the tread (8) of the screw (5) is larger than the open width of the opening (20) of the decoupling element (11).

Heat shield according to one of the preceding claims characterized in that at least two metal sheet layers (2) forming a housing are attached to each other at least in sections along their edge, with the housing comprising at least one passage opening (3) for receipt of a fastening means (5) , with a decoupling element (10) being arranged in at least one of the passage openings (3) .

Heat shield according to the preceding claim characterized in that the passage opening (3) is arranged in an area in which no intermediate layer is arranged between the two metal sheet layers (2) of the housing.

Heat shield according to one of the preceding claims characterized in that at least one element is different from another element from the same or another group of elements with respect to at least one of length, width, course and distance to its neighbours with the groups of elements comprising: the group of linking elements (12) extending essentially in a radial direction, the group of retainer elements (14); and the group of clamping elements (16).