DE202016102418U1 - heat shield - Google Patents

Abstract

Heat shield (12) for mounting on a component to be shielded (3), wherein the heat shield (12) is at least partially tubular, so that the heat shield (12) can enclose the component (3), and at least one outer layer (1) and an insulating layer (2) arranged on an inner side of the outer layer (1), wherein the outer layer (2) has at least one stress bead (6, 7, 8), the course of which is a component in the longitudinal direction (L) of the heat shield (12) and which is adapted to exert a defined restoring force on the heat shield (12) transversely to the longitudinal direction (L) of the heat shield (12), so that the heat shield (12) can enclose the component to be shielded (3) with a defined voltage.

Description

The present invention relates to a heat shield with direct insulation, in particular for mounting on a catalytic converter or a particle filter for an internal combustion engine.

Heat shields with direct insulation comprise an outer layer and an insulating layer and abut directly on the component to be shielded. In the prior art direct insulation heat shields are known which have a constant circumference or partial circumference. This is a problem, especially when mounting on catalytic converters and particle filters for internal combustion engines. The tubes terminating the catalytic converters to the outside are calibrated, for example, to different diameters in the case of catalysts of one series. The insulation layers have due to the manufacturing process on large tolerances in thickness and density. However, the insulation layer should optimally follow the outer contours of the catalyst after assembly. When mounting with sheet metal half shells as an outer layer of the heat shield on the catalyst, thereby setting different Verbaukräfte in the heat shield, which pull different degrees on the connecting straps of the sheet metal half shells, whereby the attachment can be partially opened via the tabs. In addition, within a series of catalysts, they cause different compression of the insulation layer from part to part. The assembly is therefore not sufficiently reproducible. Here it comes within the same heat shield in one extreme to the divergence of the half-shells, in the other extreme to a loose shoring without bias. In addition, the insulating layers are also pressed to varying degrees under the catalysts of a series. This also changes the density of the insulation material and thus its thermal conductivity. Furthermore, the different bias voltages vary the vibration behavior within the heat shield, which has a negative effect on the durability.

The object of the present invention is therefore to provide a heat shield with direct insulation for mounting on a component to be shielded, which is able to compensate for manufacturing tolerances of the heat shield and the component, so that the heat shield can be mounted with a defined contact pressure.

This object is achieved by a heat shield according to claim 1 and an assembly according to claim 16. Advantageous embodiments of the invention are listed in the dependent claims.

According to the invention, the heat shield for mounting on a component to be shielded at least partially tubular, so that the heat shield can enclose the component. The heat shield comprises at least one outer layer and an insulating layer arranged on an inner side of the outer layer, wherein the outer layer has at least one stress bead. The course of the at least one stress bead has a component in the longitudinal direction of the heat shield. The stress bead is designed to exert a defined restoring force on the heat shield transversely to the longitudinal direction of the heat shield, so that the heat shield can enclose the component to be shielded with a defined tension.

Due to the at least one stress bead in the outer layer tolerance variations of catalyst diameter, insulation layer and outer layer can be compensated. The at least one stress bead is preferably designed so that they can build up the radial resistance to the mounting voltage of the layers within a constant working path and thus can establish a balance. Thus, the mounting voltage, the voltage in the insulation layer and the thermal conductivity of the insulation layer remain the same for all components. Furthermore, the at least one stress bead makes it possible to set an optimum density of the insulation layer, so that the lowest thermal conductivity can be set for a given application weight.

The stress bead can be arranged only in a region along the longitudinal direction of the heat shield, which corresponds to a region of the component in which the cross-sectional area of the component is greatest and / or in which the cross-sectional area over at least 1/6, preferably 1/6 to 1/3, the longitudinal extent of the component is constant or only varies by up to 1/10 of the diameter of the component. By arranging the stress bead in the area in which the cross-sectional area of the component is greatest, the greatest possible absolute tolerance compensation is possible, because here also usually the largest circumferential length of the component is given. By only a necessary portion of the outer layer is provided with a stress bead, with sufficient effort, a sufficient tolerance compensation can be created.

Advantageously, the stress bead extends at least over 50% of the length of the heat shield or the length of the region of the heat shield corresponding to the region of the component in which the cross-sectional area of the component is greatest and / or in which the cross-sectional area is at least 1/6 , preferably 1/6 to 1/3, the longitudinal extent of the component is constant or varies only by up to 1/10 of the diameter of the component. This is necessary in order to obtain a sufficient compensation effect of the stress bead and a defined contact pressure of the heat shield in the region in which the stress bead is arranged.

Furthermore, it is advantageous if the stress bead extends at an angle of ≦ 30 ° to the longitudinal direction of the heat shield in order to be able to effectively compensate for diameter tolerances of the component to be shielded and / or of the heat shield.

The width, that is to say the extent in the outer layer perpendicular to the longitudinal extent of the stress bead, of the stress bead is preferably 4 to 20 mm, in particular 4 to 10 mm. The height, ie the extent perpendicular to the outer layer, the stress bead is preferably 4 to 12 mm, in particular 5 to 8 mm. Depending on the thickness of the insulating layer and the circumference of the catalyst body, the stress bead may have a compensation length of 2 to 8 mm, in particular 3 to 5 mm. Compensation length here is to be understood as meaning a maximum circumferential enlargement of the outer layer by pulling the stress bead during assembly. The stress bead is shallower, but preferably not completely flat pulled.

The stress bead can be oriented in such a way that the bead roof is facing or away from the insulation layer. The choice of orientation of the sock roof is influenced on the one hand by the available space. In a tight space, it may be advantageous to turn the bead roof of the insulation layer. On the other hand, it must then be taken very much to ensure that the stress bead does not have too great compression forces, as otherwise over-compression of the insulation material may occur. In most cases, the orientation of the beaded roof facing away from the insulation layer offers greater design freedom and greater tolerances.

The insulating layer of the heat shield may comprise a fiber-based material. The fiber-based material preferably contains glass fibers, in particular fibers of E glass or ECR glass, silicate fibers or mixtures thereof. The fibers may in this case be needled, sewn, bound, in particular bound by means of a polymer-based binder, or laminated.

In a preferred embodiment of the invention, the heat shield has two half shells which can be connected to one another, wherein at least one stress bead is arranged in at least one of the half shells. Alternatively, the heat shield can have two half shells which are movably connected to one another, wherein at least one stress bead is arranged in at least one of the half shells. The half-shells can advantageously be movably connected via a hinge joint. This may be formed directly from the outer layer or formed as a separate element, for. B. in the form of an inserted pin. However, this also requires a deformation of the outer layer for receiving the pin. Furthermore, it is also conceivable that a hinge function results by nesting of the edge regions of the half-shells. The division of the heat shield in half shells allows easy mounting on the component to be shielded.

In particular, the half-shells can be connected or connected to one another along a parting plane, and the stress bead can extend at an angle of ≦ 30 ° to the longitudinal direction of the parting plane.

Furthermore, each of the half-shells may have, at least in sections, at least one flange by means of which the half-shells for mounting the heat shield on a component can be tensioned against one another. In particular, the stress bead can then run at an angle of ≦ 30 ° to the longitudinal direction of the flange.

Alternatively, the half-shells for mounting the heat shield to a component by means of crimping, welding or clinching or clamped against each other by clamps.

In a further preferred embodiment of the invention, the outer layer may be a sheet metal layer with a layer thickness of 0.1 to 1 mm, in particular from 0.15 to 0.4 mm, particularly preferably from 0.2 to 0.3 mm.

The insulating layer may have a layer thickness of 3 to 15 mm, preferably 4 to 10 mm, in particular 4 to 8 mm.

The heat shield according to the invention is provided in particular for mounting on a catalytic converter and / or a particle filter for an internal combustion engine.

The invention further comprises an assembly comprising a previously described heat shield and a component to be shielded, wherein the heat shield encloses the component to be shielded with a defined voltage. It is particularly advantageous if the insulating layer of the heat shield bears flat against the component, in particular over its entire area, in order to obtain an effective insulation effect.

In the following some examples of a heat shield according to the invention and an assembly according to the invention are described. The shown individual features of an example can also independently of the specific example and in any combination further develop the present invention.

Embodiments of the invention are illustrated in the figures and will be explained in more detail with reference to the following description. In the embodiments described herein, identical or similar elements or features are designated with identical or similar reference numerals, so that their detailed description need not be repeated. The embodiments described below include a variety of features and related advantageous features of the present invention. However, the features described in connection with the various embodiments can each also represent an advantageous development of the invention. That is, the individual features of specific embodiments may also be combined with other embodiments or with individual features of other embodiments, separately from the further features of the respective embodiment. Show it

1a 1 is a schematic exploded view of a catalyst assembly with a direct insulation heat shield according to the prior art,

1b a cross section through a catalyst assembly with a direct insulation heat shield according to the prior art,

2a a cross section through an assembly according to the invention with catalyst and heat shield according to a first embodiment,

2 B the embodiment 2a , wherein the catalyst has a larger diameter than in 2a .

3 a cross section through an assembly according to the invention with catalyst and heat shield according to a second embodiment,

4 a cross section through an assembly according to the invention with catalyst and heat shield according to a third embodiment,

5 a longitudinal section through a catalyst,

6 a detailed view of a cross section through the assembly according to the first embodiment,

7 a detailed view of a cross section through a module with catalyst and heat shield according to a fourth embodiment of the invention,

8th a detail view of a cross section through a module with catalyst and heat shield according to a fifth embodiment of the invention and

9 a cross section of an assembly according to the invention with catalyst and heat shield according to a sixth embodiment.

1 shows a catalyst assembly with a direct insulation heat shield 100 according to the prior art in a schematic exploded view. The catalyst assembly comprises a cylindrical catalyst inside 30 as well as a heat shield 10a . 10b . 20a . 20b , which simplifies assembly in two half-shells 10a . 20a and 10b . 20b divided and surrounds the catalyst along its lateral surface. The heat shield comprises an outer, rigid sheet metal layer 10a . 10b , as well as an isolation situation 20a . 20b , The isolation situation 20a . 20b lies directly on the entire lateral surface of the catalyst 30 and is due to the rigid sheet metal layer 10a . 10b around the catalyst 30 curious; excited. The heat shield 100 is made to fit a catalytic series. Due to the rigid outer sheet metal layer 10a . 10b Manufacturing tolerances of the catalyst and / or the heat shield can not be compensated so that it comes to a non-uniform contact pressure of the insulating layer on the catalyst, resulting in a deteriorated insulation effect.

1b shows the assembly 1a in cross section. The half-shells 10a . 20a and 10b . 20b are by a crimp in the sheet metal layer 10 clamped together and thus form the heat shield 100 , Here, the half shell 10a the sheet metal situation 10 at a separation point 111 a fold 40a and the other half shell 10b the sheet metal situation 10 a footbridge 50b on, so the fold 40a the jetty 50b can enclose. At the other separation point 111b has the half shell 10a the sheet metal situation 10 a footbridge 50a and the other half shell 10b the sheet metal situation 10 a fold 40b on, so the fold 40b the jetty 50a can enclose.

2a shows a cross section of an assembly with catalyst 3 and heat shield 12 according to a first embodiment of the invention in a schematic representation. The assembly is cylindrical and has a substantially circular cross-section. Inside the assembly is the cylindrical catalyst 3 also with a substantially circular cross-section. To the catalyst 3 or its Outer tube around is the heat shield 12 directly over the entire lateral surface of the catalyst 3 on the catalyst 3 at. The heat shield 12 has an insulation layer 2 on which directly on the catalyst 3 is applied. Furthermore, the heat shield has 12 an external sheet metal layer 1 on which the insulation layer along the lateral surface of the catalyst 3 surrounds. The heat shield 12 also has a separation point 11 on which the heat shield 12 perpendicular to the lateral surface of the catalyst 3 and parallel to the longitudinal axis of the catalyst 3 Shares, so the heat shield 12 for simplified mounting on the catalytic converter 3 can be bent and bent. The longitudinal direction of the catalyst 3 is additionally indicated by the reference symbol L parallel to the actual longitudinal axis. The heat shield can then by means of crimping 4 . 5 be tense. For this purpose, the sheet metal layer 1 on one side of the separation point 11 a footbridge 5 and on the other side of the separation point 11 a fold 4 on, so the fold 4 can enclose the bridge. On the parting line 11 opposite side of the assembly has the sheet metal layer 1 a stress bead 6 with a catalyst 3 facing away from (convex) Sick roof on. The stress bead 6 runs parallel to the longitudinal axis of the catalyst 3 and is formed to have a restoring force along the circumference of the catalyst 3 on the sheet metal layer 1 can exercise. In this way, the voltage bead provides 6 even with manufacturing variations in the diameter of the catalyst 3 and / or the heat shield 12 for a consistent tension of the heat shield 12 around the catalyst 3 and thus for a constant density of the insulation layer 2 , The exact positioning of the stress bead 6 along the circumference of the assembly is generally carried out depending on the voltage pattern, namely where the largest tolerance compensation is needed.

2 B shows an analogous assembly as in 2a but with the catalyst 3 although he is from the same series as the catalyst 3 of the 2a , a larger diameter than in 2a having. The stress bead 6 equals the larger diameter of the catalyst 3 by (partial) flat pulling and causes so that the strain of the heat shield 12 around the catalyst 3 the same as in the assembly of the 2a ,

3 shows a cross section of a second embodiment of an assembly according to the invention in a schematic view. In contrast to the first embodiment, the heat shield 12 two half-shells 1a . 2a and 1b . 2 B on, which at two opposite separation points 11a and 11b contiguous. At the separation points 11a and 11b are the half-shells 1a and 1b the sheet metal situation 1 by crimping 4 . 5 connected and clamped together analogously to the first embodiment. Furthermore, the half shell has 1a the sheet metal situation 1 over a convex stress bead 6a , which are centered between the separation points 11a . 11b in the half shell 1a the sheet metal situation 1 is arranged. The central positioning of the stress bead 6 allows the most flexible entry possible. Moreover, it is here in the area in which the voltage lines adjust.

4 shows a cross section of a third embodiment of an assembly according to the invention in a schematic view. In contrast to the module of 3 is a second convex stress bead 6b in the half shell 1b the sheet metal situation 1 of the heat shield 12 in the middle between the separation points 11a and 11b arranged. The additional stress bead 6b allows greater tolerance compensation of the heat shield 12 along the circumference of the catalyst 3 ,

5 shows a schematic view of a longitudinal section of a catalyst, more precisely an outer tube of a catalyst 3 and the preferred portions of the catalyst or outer tube for the arrangement of the stress beads. section 3a indicates an incoming tube from the turbo outlet into the catalyst 3 , section 3b serves the extension of the turbo outlet on the catalyst cross section. section 3h serves for the taper of the catalyst cross section on the pipe cross section of the subsequent sections of the exhaust system. section 3i denotes an exit tube from the catalyst 3 , In the sections 3c to 3g the catalyst diameter is graded in three stages, the diameter of 3c to 3g decreases. The step transitions are 2 to 15 mm, preferably 3 to 8 mm and are in sections 3d and 3f , The length of the sections is 30 to 350 mm, preferably 50 to 200 mm. Within the sections 3c . 3e and 3g the catalyst diameter is largely constant. section 3c is the section with the largest diameter. In the region of the heat shield corresponding to this section, there is preferably always a stress bead. Here, the most efficient tolerance compensation takes place, since here is the largest circumferential length to be compensated. Optionally, stress beads can also be found in the sections 3e and 3g be arranged.

6 shows a schematic detail view of a cross section of an assembly according to the invention, wherein the heat shield 12 a stress bead 6 has, similar to the previous embodiments, convex and in which only the squeezing feet 16a . 16b on the isolation layer 2 rests (embodiment 1). The heat shield 12 is in the design of its sheet metal layer 1 and its isolation situation 2 by binder addition to the fiber mat designed so that when tightening the heat shield 12 around the catalyst 3 the isolation situation 2 not in the stress bead 6 runs in, since the insulation layer is too stiff for this purpose.

7 shows a schematic detail view of a cross section of an assembly according to the invention in a fourth embodiment. Here is the sheet metal layer 1 three convex tensions 6 . 7 . 8th on. The heat shield 12 is designed so that the insulation layer 2 partly in the stress beads 6 . 7 . 8th the sheet metal situation 1 into running. Here, the insulation layer contains only a small amount of binder, which also not uniform over the entire thickness of the insulation layer 2 is distributed: the sheet metal layer 1 facing half of the insulation layer 2 is free of binder, so that this surface is slightly more flexible than the outer tube of the catalyst 3 facing.

8th shows a schematic detail view of a cross section of an assembly according to the invention in a fifth embodiment. Here is the sheet metal layer 1 two tension beads 6 ' and 8th' on, the beaded roof insulation situation 2 directed (concave). Between these concave stress beads 6 ' and 8th' is a third, convex tension bead 7 in the sheet metal situation 1 arranged. The heat shield 12 is designed so that the concave stress beads 6 ' and 8th' the sheet metal situation 1 essentially completely in the insulation layer 2 push in, and the insulation layer 2 the convex stress bead 7 the sheet metal situation 1 essentially completely. Here is the isolation situation 2 executed entirely without binder, so that it is much more flexible than in the two previous embodiments.

Whether and how strong the isolation situation 2 runs into a stress bead or a voltage bead in the insulation layer 2 Incidentally, pressing in depends on the installation space or the size of the stress bead, the orientation of the stress bead roof, the local compression or the ratio of the height of the stress bead to the thickness of the insulation layer.

9 shows a cross section of a sixth embodiment of an assembly according to the invention in a schematic view. The heat shield 12 The assembly is the same as the assembly in 4 from two half-shells 12a and 12b , In contrast to the heat shield 12 out 4 has the heat shield 12 of the 9 at the separation point 11b a hinge joint 9 and at the separation point 11a a flange connection with flanges 13a . 13b for clamping the two half-shells 12a and 12b to each other. The hinge joint allows for easier installation of the heat shield 12 on the catalyst 3 because it can be opened and closed along its longitudinal axis. Furthermore, the heat shield differs 12 of the 9 from the heat shield 12 of the 4 in that each two convex stress beads 6a . 7a and 6b . 7b in the half-shells 1a and 1b the sheet metal situation 1 are arranged. The tension beads 6a . 7a and 6b . 7b are so in the half shells 1a and 1b arranged them to their adjacent separation points 11a . 11b a distance of about 1/8 of the circumference of the heat shield 12 along the perimeter of the heat shield 12 and to each other a distance of about 1/4 of the circumference of the heat shield 12 along the perimeter of the heat shield 12 to have.

The figures and embodiments described above merely show assemblies in which the component to be shielded is a catalyst. However, the description can be directly applied to other components, such. B. transferred a particulate filter by replacing the catalyst with the appropriate component.

Claims (17)

Heat shield ( 12 ) for mounting on a component to be shielded ( 3 ), whereby the heat shield ( 12 ) is at least partially tubular, so that the heat shield ( 12 ) the component ( 3 ) and at least one outer layer ( 1 ) and one on an inner side of the outer layer ( 1 ) arranged insulation layer ( 2 ), wherein the outer layer ( 2 ) at least one stress bead ( 6 . 7 . 8th ) whose profile is a component in the longitudinal direction (L) of the heat shield ( 12 ) and which is adapted to a defined restoring force on the heat shield ( 12 ) transverse to the longitudinal direction (L) of the heat shield ( 12 ), so that the heat shield ( 12 ) the component to be shielded ( 3 ) can enclose with a defined voltage. Heat shield ( 12 ) according to the preceding claim, wherein the stress bead only in a region along the longitudinal direction (L) of the heat shield ( 6 . 7 . 8th ) arranged with a portion of the component ( 3 ) corresponds, in which the cross-sectional area of the component ( 3 ) is the greatest and / or in which the cross-sectional area over at least 1/6, preferably 1/6 to 1/3, the longitudinal extent of the component ( 3 ) is constant or only up to 1/10 of the diameter of the component ( 3 ) varies .. Heat shield ( 12 ) according to one of the preceding claims, wherein the stress bead ( 6 . 7 . 8th ) at least over 50% of the length of the heat shield ( 12 ) or the length of the area of the heat shield ( 12 ) connected to the area of the component ( 3 ) corresponds, in which the cross-sectional area of the component ( 3 ) is the greatest and / or in which the cross-sectional area over at least 1/6, preferably 1/6 to 1/3, the longitudinal extent of the component ( 3 ) is constant or only up to 1/10 of the diameter of the component ( 3 ) varies. Heat shield ( 12 ) according to one of the preceding claims, wherein the stress bead ( 6 . 7 . 8th ) at an angle of ≤ 30 ° to the longitudinal direction (L) of the heat shield ( 12 ) runs. Heat shield ( 12 ) according to one of the preceding claims, wherein the insulation layer ( 2 ) comprises a fiber-based material. Heat shield ( 12 ) according to the preceding claim, characterized in that the fiber-based material contains glass fibers, in particular fibers of E glass or ECR glass, silicate fibers or mixtures thereof. Heat shield ( 12 ) according to one of the two preceding claims, wherein the fibers are needled, sewn, bound, in particular bound by means of a polymer-based binder, or laminated. Heat shield ( 12 ) according to one of the preceding claims, wherein the heat shield ( 12 ) two interconnecting half-shells ( 12a . 12b ), wherein in at least one of the half shells ( 12a . 12b ) at least one stress bead ( 6 . 7 . 8th ) is arranged. Heat shield ( 12 ) according to one of claims 1 to 7, wherein the heat shield ( 12 ) two half-shells ( 12a . 12b ), wherein in at least one of the half shells ( 12a . 12b ) at least one stress bead ( 6 . 7 . 8th ) is arranged. Heat shield ( 12 ) according to one of the two preceding claims, wherein the half shells ( 12a . 12b ) along a parting plane ( 11 ) are connectable or connected to each other and the stress bead ( 6 . 7 . 8th ) at an angle of ≤ 30 ° to the longitudinal direction (L) of the parting plane. Heat shield ( 12 ) according to one of the two preceding claims, wherein each of the half-shells ( 12a . 12b ) at least in sections at least one flange ( 13a . 13b ), by means of which the half shells ( 12a . 12b ) for mounting the heat shield ( 12 ) on a component ( 3 ) are tensioned against each other. Heat shield ( 12 ) according to one of claims 8 or 9, wherein the half shells ( 12a . 12b ) for mounting the heat shield ( 12 ) on a component ( 3 ) by means of crimping, welding or clinching or clamped against each other by means of clamps. Heat shield ( 12 ) according to any one of the preceding claims, wherein the outer layer comprises a sheet metal layer ( 1 ) with a layer thickness of 0.1 to 1 mm, in particular from 0.15 to 0.4 mm, particularly preferably from 0.2 to 0.3 mm. Heat shield ( 12 ) according to one of the preceding claims, wherein the insulation layer ( 2 ) has a layer thickness of 3 to 15 mm, preferably from 4 to 10 mm, particularly preferably from 4 to 8 mm. Heat shield ( 12 ) according to one of the preceding claims for mounting on a catalytic converter and / or a particle filter for an internal combustion engine. Assembly comprising a heat shield ( 12 ) according to one of the preceding claims and a component to be shielded ( 3 ), whereby the heat shield ( 12 ) the component to be shielded ( 3 ) encloses with a defined tension. Assembly according to the preceding claim, wherein the insulation layer ( 2 ) of the heat shield ( 12 ) surface, in particular full surface, on the component ( 3 ) is present.

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