HEAT SHIELD AND PART SHIELDED WITH SUCH A HEAT SHIELD

Abstract

The present invention relates to a heat shield for shielding of hot areas, such as hot areas of a combustion engine as well as a part that is shielded with such a heat shield. The heat shield for shielding of hot areas, e. g. of a combustion engine, with at least one metal sheet layer, characterized in that the insulating layer comprises a metallic grid, which is embedded into a fiber mat.

Claims

1-21. (canceled)

22. A heat shield for shielding of hot areas of a combustion engine comprising: at least one metal sheet layer; an insulating layer arranged adjacent to the metal sheet layer, wherein the insulating layer comprises a metallic grid, which is embedded into a fiber mat.

23. The heat shield according to claim 22, wherein at least a part of the fibers of the fiber mat penetrates openings of the metallic grid.

24. The heat shield according to claim 22, wherein the metallic grid relative to the respective local thickness of the fiber mat is distanced to the surface of the fiber mat facing the metal sheet layer by at least 5% of the thickness of the fiber mat and/or to the surface of the fiber mat pointing away from the metal sheet layer by at the most 35% of the thickness of the fiber mat and the metallic grid.

25. The heat shield according to claim 22, wherein the thickness of the fiber mat is ≧4.5 mm and ≦15 mm.

26. The heat shield according to claim 22, wherein the fiber mat comprises at least one of glass fibers, mineral fibers and carbon fibers.

27. The heat shield according to claim 26, wherein the fibers of the fiber mat as fiber pile or fiber loop penetrate the metallic grid orthogonal to its facial extension or are interwoven with the metallic grid.

28. The heat shield according to claim 26, wherein the fibers are adhesively bonded to the metallic grid.

29. The heat shield according to claim 26, wherein the fibers of the fiber mat in individual areas or throughout the fiber mat are fixed with a binder.

30. The heat shield according to claim 29, wherein the fibers of the fiber mat are fixed with the binder in edge regions.

31. The heat shield according to claim 29, wherein the fibers of the fiber mat are fixed with the binder in areas close to surfaces of the fiber mat.

32. The heat shield according to claim 29, wherein the binder content in the fiber mat is ≦25% of the total weight of the fiber mat.

33. The heat shield according to claim 22, wherein the fiber mat contains no binder.

34. The heat shield according to claim 26, wherein one, several or all of the fibers comprise one or several metallic fibers as core.

35. The heat shield according to claim 26, wherein free ends of the fibers engage behind bridges of the metallic grid.

36. The heat shield according to claim 26, wherein hooks protrude from the metallic grid, the hooks engage behind the fibers of the fiber mat, with the hooks protruding less far from the plane of facial extension of the metal grid than the fibers of the fiber mat.

37. The heat shield according to claim 22, wherein the metallic grid is a metallic weave, expanded metal sheet, perforated metal sheet, or tanged metal sheet.

38. The heat shield according to claim 23, wherein at least one opening of the metallic grid is round, triangular, square, rhombic or hexagonal.

39. The heat shield according to claim 38, wherein at least one opening of the metallic grid is shaped as a regular hexagon where the corners are rounded with corner radii R with 0.2 mm≦R≦1.0 mm.

40. The heat shield according to claim 23, wherein at least one of the openings of the metallic grid in a top view to the openings show a regular shape, which can be transferred into itself with a rotation around its central axis by 360°/n with n being a natural number.

41. The heat shield according to claim 23, wherein at least one opening of the metallic grid in a top view to the openings have the basic shape of a polygon with protrusions protruding from the sides of the polygon into the opening, where the protrusions are designed as hooks, which engage behind the fibers of the fiber mat, where the hooks protrude less far from the plane of facial extension of the metallic grid than the fibers of the fiber mat.

42. The heat shield according to claim 23, wherein the mesh width of the openings of the metallic grid is ≧8 mm and ≦25 mm.

43. The heat shield according to claim 22, wherein the fiber mat is a weave selected from the group of a loop weave, a pile, a knitted fabric, a warp knitted fabric, a roving or a fleece.

44. The heat shield according to claim 43, wherein the fiber mat is a) a loop weave with a density in loops of ≧2/cm.sup.2 and ≦30/cm.sup.2 or b) a pile with a fiber density in erected fibers of ≧9/cm.sup.2 and 100/cm.sup.2.

45. The heat shield according to claim 22, wherein a side of the fiber mat pointing away from the metal sheet layer rests on the area to be shielded or is arranged at least adjacent to the area to be shielded with a maximum distance of ≦3 mm over at least 75% of the contact surface.

Description

[0032] It is shown in:

[0033] FIG. 1: A heat shield according to the invention;

[0034] FIG. 2: A part shielded according to the invention in an exploded representation;

[0035] FIG. 3: Two variants of a heat shield according to the invention in a partial view;

[0036] FIGS. 4 to 9: Sections of further heat shields according to the invention; and

[0037] FIG. 10: two schemes for the production of heat shields according to the invention.

[0038] FIG. 1 shows a heat shield 1. This heat shield 1 comprises a metal sheet layer 2, which is adapted to the shape of the part to be shielded. In FIG. 1, the heat shield is shown in a top view to the inner side of the heat shield 1, which is arranged adjacent to the part to be shielded.

[0039] On this side, an insulating layer 3 is arranged adjacent to the metal sheet layer 2. Passage openings 5a, 5b for the fastening of the heat shield at the part to be shielded, using, e.g. screws, extend both through the metal sheet layer 2 and through the insulating layer 3. In addition, areas 8 are marked, in which the heat shield shows convexities. These areas 8 underline the complex total shape of the heat shield, which has to be realized by the insulating layer 3, too. According to the invention, the insulating layer comprises a metallic grid, which is embedded into a fiber mat 10, which fiber mat is visible from above in FIG. 1.

[0040] FIG. 2 shows a shielded part according to the present invention in an exploded view. The shielded part comprises a hot constructional element 6, e.g. an exhaust muffler or a catalyst. This hot constructional element 6 is part of an exhaust line 7 of a combustion engine.

[0041] FIG. 2 in an exploded view shows two half shells 3a and 3b of an insulating layer. On both these two half shells 3a and 3b, two half shells 2a and 2b of a metal sheet layer have been arranged. The layers 2a, 2b, 3a and 3b this way form the heat shield according to the invention.

[0042] The half shells 3a and 3b are realized as insulating layer, namely as fiber mat, into which a metallic grid is embedded. As is shown in FIG. 2, such an insulating layer can be shaped deliberately due to the embedded metallic grid and subsequent to this is able to maintain this shape.

[0043] The shape of the heat shield 2 shown in FIG. 2 as an example corresponds to a shape of low complexity. In particular with shapes with a plurality of recesses and protrusions, the embedding of a metallic grid provides considerable advantages during shaping and for the maintenance of this shape.

[0044] FIG. 3 in partial figures A to C shows different variants of an insulating layer 3 of a heat shield according to the invention.

[0045] In FIG. 3A, a section of an insulating layer 3 is illustrated in a top and transparent view. The insulating layer 3 comprises a fiber mat 10, into which a metallic grid 20 is embedded. The metallic grid 20 encloses openings 21, with the fibers of the fiber mat 10 penetrating the openings 21 and this way being embed in the metallic grid. The metallic grid is arranged approximately at the center with respect to the thickness of the insulating layer 3 and realized as metallic grid with longitudinal threads 23a to 23d and transverse threads 23a′ to 23d′.

[0046] In FIG. 3B, a cross-section through the insulating layer 3 from FIG. 3A is shown in a first variant. Here the longitudinal threads 23′a etc. each extend on one side of all transverse threads 23a to 23d within the insulating layer 3 and the fiber mat 10.

[0047] In FIG. 3C, a cross-section through FIG. 3A in a further variant is shown. In this case, a weave is given. The longitudinal fibers, as is shown for the longitudinal fiber 23a′, extend alternatingly above and below the transverse fibers, as is shown for the transverse fibers 23a to 23d, within the insulating layer 3 and within the fiber weave 10.

[0048] FIG. 4A shows a further section of an insulating layer 3 in a transparent view. The insulating layer 3 comprises a fiber mat 10, which is embedded in a grid of expanded metal. The grid of expanded metal now comprises longitudinal bridges 23a, 23c and transversal bridges 23b, 23d and 23e. These bridges form rhombic passage openings 21 between the bridges.

[0049] FIG. 4B shows a cross-section through the insulating layer 3 in FIG. 4A along section A-A. Here, a total of five of the rhombic passage openings 21a to 21e are marked with reference numbers.

[0050] FIG. 5 shows a top-view to an insulating layer 3, as it is illustrated in FIG. 3C in cross-section. The insulating layer 3 comprises a woven grid 20, which is embedded into a fiber mat 10. The second fiber mat, which is applied to the metal grid 20 from the upper side, is not shown. The fixation of both fiber mats through the woven grid 20 can for instance be realized during the shaping of the insulating layer 3 or also using a needle process. The woven grid 20 therefore is located centrally in the insulating layer 20 comprising the two fiber mats.

[0051] FIG. 6 in partial figures A and B shows the design of a metallic grid 20 according to the invention. The metallic grid 20 comprises passage openings 21, which show a form with three aisles. Each aisle of an opening here is arranged between two aisles of an adjacent opening, so that arch-shaped bridges 23 result between the aisles. The bridges 23 and the entire grid 20 can easily be deformed three-dimensionally, so that it can be adapted to each three-dimensional shape in an almost ideal manner, e.g. to the metal sheet layer of the heat shield. Within each of the aisles of the openings 21, protrusions 24a, 24b having a general shape of landing stages with hook-shaped free ends are arranged which start from bridges. They extend freely into the opening, and, as shown in FIG. 6B in cross-section along section B-B in FIG. 6A are bent from the plane of the metallic grid 20 with an angle. The angle can amount to e.g. 70° as shown or up to 90°. An almost orthogonal passage of the bridges, thus an angle close to 90° is preferred in this respect. At their ends, they comprise a hook-shaped element 25a, 25b, 25c, so that the hooks 24a to 24c can get caught with the fibers of the fiber mat 10 passing through the passage openings 21. This way, the grid is securely held in the fiber mat 10 and embedded into the latter.

[0052] FIG. 7 in partial figures A and B shows a top-view to and a cross-section through an insulating layer 3 and a metallic layer 2 of a heat shield according to the invention.

[0053] While in the preceding examples, the fiber mat 10 was realized as pile, in this example the fiber mat 10 is realized as an arrangement of loops. The loops here pass both through the passage openings 21 as well as through the bridges of the grid 20. This way, the grid is anchored in an ideal manner within the fiber mat 10; in the present example it is arranged approximately in the middle.

[0054] In FIG. 8, in partial figures A and B, a further embodiment of an insulating layer 3 of a heat shield according to the invention is shown together with the metallic layer 2 in top-view and cross-section. While the metallic grid is arranged approximately centered relative to the thickness of the fiber mat 10 in FIG. 7, the metallic grid 20 in FIG. 8 is arranged outside of the center of the fiber mat 10 relative to its thickness Hf, namely closer to the metallic layer 2 of the heat shield according to the invention. In the example of FIG. 8, the metallic grid 20 nevertheless is also embedded into the fiber mat 10, but relative to the thickness, a larger part of the fiber mat is given one-sided in the direction of the part to be shielded, thus distanced to the metallic layer 2. Relative to the thickness Hf of the fiber mat 10, the metallic grid 20 in FIG. 8 is arranged distanced by about Hm=10% from the surface of the fiber mat 10 facing the metallic layer 2. The distance Ho from the surface of the fiber mat pointing away from the metallic layer 2 here amounts to more than 80% of the thickness Hf of the fiber mat 10.

[0055] FIG. 9 shows a further embodiment of an insulating layer 3 of a heat shield 1 according to the invention. Here, the fibers 11 of the fiber mat 10 are loosely filled into the passage openings 21 of the metallic grid 20, which is designed comparable to FIG. 10. The illustration does not reflect the actual density of the fibers 11, in order to remain clear. An advantageous production of this embodiment of the insulating layer 3 results, when the fibers 11 are blown into the metallic grid 20. Here, a densification of the fiber-metal grid-composite in its plane can take place during the reshaping of the insulating mat 3, so that an improved long-term stability of the insulating layer 3 results.

[0056] FIG. 10 in two partial FIGS. 10A and 10B illustrates schematically the major ways to produce the heat shield 1 from a metal sheet blank 200 and a blank 300 of the insulation layer based on a fiber mat 10 with an embedded metallic grid. In the approach of FIG. 10A, the blanks are put one on the other and then jointly deformed to make a heat shield 1 with a metal sheet layer 2 and an insulating layer 3. In the approach of FIG. 10B, the two flanks 200, 300 are deformed individually and then put together in order to make a heat shield 1 with a metal sheet layer 2 and an insulating layer 3. In both cases, the metal sheet layer 2 shows a larger extension than the insulating layer 3.