Support structure for heating substrate

Abstract

The invention relates to a support structure (1) for positioning a heating substrate in an exhaust section that is spatially delimited by a housing, the heating substrate being formed from a honeycomb body having a plurality of flow channels that can be flowed through in a main flow direction, the heating substrate being supported by the support structure (1) relative to an inner surface of the housing, the heating substrate is fixed relative to the support structure (1) by means of a plurality of coupling elements (4), the coupling elements (4) being inserted into individual cells of the heating substrate formed by the flow channels and being permanently connected thereto, the free ends of the coupling elements (4) being directly or indirectly connected to the support structure (1), a tolerance compensation element being provided in each case, the tolerance compensation element compensates for the positional tolerances of the coupling element (4) in at least two spatial directions by means of a connecting element (5) having at least one elongated hole. The invention further relates to a method for connecting a support structure to a heating substrate.

Description

Technical Field

[0001] 1. The present invention relates to a support structure for positioning / arranging a heating substrate in an exhaust section spatially limited by a housing, wherein the heating substrate is formed by a honeycomb body having a plurality of flow channels that can be flowed through along a main flow-through direction, wherein the heating substrate is supported relative to the inner surface of the housing by the support structure, and the heating substrate is fixed relative to the support structure by means of a plurality of coupling elements, wherein the coupling elements are inserted into respective cells formed by the flow channels of the heating substrate and are permanently connected to these cells. Furthermore, the present invention relates to a method for connecting the support structure to the heating substrate. Background Art

[0002] 2. In order to heat the exhaust gas in the exhaust section downstream of an internal combustion engine or the exhaust gas flowing in the exhaust section, electric heating elements are currently commonly used. The goal pursued at this time is to reach a temperature threshold more quickly, starting from which the harmful substances carried in the exhaust gas can be effectively converted. This is necessary because the catalytically active surface for exhaust gas aftertreatment of the catalytic converter installed in the exhaust section can only achieve sufficient conversion of the corresponding harmful substances starting from the lowest temperature, the so-called light-off temperature.

[0003] 3. Solutions known in the prior art include so-called heated catalytic converters, which have a metal structure or a metal-coated ceramic structure connected to a voltage source and can be heated using ohmic resistance.

[0004] 4. A heatable metal structure can, for example, consist of a honeycomb body made of metal foil. For this purpose, a plurality of smooth and / or at least partially structured metal foils are stacked on top of each other and wound around at least one pivot point to form a honeycomb body. The substrate formed by the metal foil can be electrically contacted and can be heated using ohmic resistance.

[0005] 5. For this purpose, the substrate must be arranged in the exhaust section and be placed upstream or downstream of a catalytic converter designed for exhaust gas aftertreatment in the flow direction of the exhaust gas.

[0006] 6. In order to position the substrate in the exhaust section and support the substrate, especially to overcome mechanical and thermal loads, such a support must be provided, i.e., the support can especially withstand high alternating thermal loads in the exhaust section, especially in a motor vehicle exhaust section, and furthermore strong and irregular mechanical loads.

[0007] 7. The connection between the support structure and the heating matrix is achieved by means of a plurality of coupling elements. Since all components have certain manufacturing tolerances related to production, tolerance compensation must be carried out to achieve stress-free assembly. In the solutions known from the prior art, it is particularly disadvantageous that the tolerance compensation of the known coupling elements is insufficient. Summary of the Invention

[0008] 8. Accordingly, an object of the present invention is to provide a support structure for a heating matrix, which has advantageous coupling elements that allow sufficient tolerance compensation. In addition, an object of the present invention is to provide a method for connecting a support structure to a heating matrix.

[0009] 9. In terms of the support structure, the object is achieved by a support structure having the features described in claim 1.

[0010] 10. An embodiment of the present invention relates to a support structure for positioning a heating matrix in an exhaust section spatially restricted by a housing, wherein the heating matrix is formed by a honeycomb body having a plurality of flow channels that can be flowed through along a main flow-through direction, wherein the heating matrix is supported by the support structure relative to the inner surface of the housing, and the heating matrix is fixed relative to the support structure by means of a plurality of coupling elements, wherein the coupling elements are inserted into the respective cells formed by the flow channels of the heating matrix and are permanently connected to these cells, wherein the free end portions of the coupling elements are respectively directly or indirectly connected to the support structure, and wherein tolerance compensation elements are respectively provided, and the tolerance compensation elements compensate for the positional tolerances of the coupling elements in at least two spatial directions.

[0011] 11. Tolerance compensation is necessary because all components have production-related tolerances. Therefore, compensation is essential for precise assembly. In addition to production-related tolerances, tolerances also arise due to the fact that the coupling elements must be inserted into the cells of the honeycomb body. At this time, slight deviations may sometimes occur. In addition, due to the shape tolerances of the honeycomb body, the coupling elements may deviate slightly from their basic positions.

[0012] 12. Preferably, it is stipulated that tolerance compensation is carried out in the connection area of the coupling elements on the support structure, because there is actually no compensation possibility for the connection on the honeycomb body.

[0013] 13. The coupling elements can be connected to the support structure directly or in the case of using intermediate elements. For example, the coupling elements can be formed by support pins known from the prior art, or can also be formed by simple metal pins according to the need for electrical insulation.

[0014] 14. The plane in which the support structure unfolds in two of the three spatial directions for which tolerance compensation must be carried out. The third spatial direction extends as the surface normal of this plane. If the coupling element is inserted into, for example, an adjacent cell of the actual target cell or the honeycomb body has manufacturing tolerances in this region, then in these two first spatial directions, the positional tolerance of the coupling element is substantially compensated. In the third spatial direction (the spatial direction in which the coupling element is inserted into the honeycomb body), the tolerance in the axial direction of the exhaust section is compensated. The tolerance in the third direction is generally less than the tolerance in the two first directions because the insertion depth into the honeycomb body is very precisely controlled by the machine and thus the deviation is very small.

[0015] 15. It is particularly advantageous if the support structure has cup-shaped chambers that are open towards the heating structure on its surface facing the heating matrix, and these cup-shaped chambers are each designed to receive the free end of the coupling element and form tolerance compensation elements.

[0016] 16. The support structure, which is substantially formed from flat sheets, can have cup-shaped chambers. The cup-shaped chambers can be directly designed on the surface of the support structure facing the heating matrix. These chambers can be directly formed in the sheet material, for example, by deep drawing or pressing. Alternatively, these chambers can also be formed by cylindrical flanges protruding from the support structure.

[0017] 17. It is also advantageous if the net opening width of the cup-shaped chambers is respectively several times the cross-section of the free end of the coupling element. Then, the free end of the coupling element can move in the two first spatial directions inside this net opening. By varying the insertion depth of the free end of the coupling element, tolerance compensation can also be carried out in the third spatial direction. At the same time, the size of the net opening determines the maximum possible tolerance compensation in the two first spatial directions, while the depth of the chamber substantially determines the maximum possible tolerance compensation in the third spatial direction.

[0018] 18. A preferred embodiment is characterized in that the depth of the cup-shaped chamber is greater than the average insertion depth of the coupling element. Thereby, it is ensured that a sufficiently large tolerance compensation is achieved.

[0019] 19. The chambers can be pre-filled with solder so that a permanent connection can be established between the support structure and the heating matrix by a simple soldering process after inserting the coupling element.

[0020] 20. In an alternative design, it is preferred that connection elements are respectively arranged between the support structure and the coupling element as tolerance compensation elements, and the connection elements are permanently connected to the support structure on one side and receive the free end of the coupling element on the other side.

[0021] 21. Further connecting elements can be advantageous for compensating tolerances. For example, the connecting element can be formed by a one-sidedly closed hollow cylinder applied to the surface of the support structure. The hollow cylinder can also be pre-filled with solder.

[0022] 22. Additionally, it is advantageous if the connecting element has an opening facing the coupling element, which opening is larger than the cross-section of the free end of the coupling element. If the tolerance compensation essentially has to be carried out in one of the two first spatial directions, an oblong opening can be provided. Alternatively, a circular or rectangular opening cross-section can be selected.

[0023] 23. In terms of the method, the object is achieved by a method having the features of claim 8.

[0024] 24. An embodiment of the invention relates to a method for connecting a support structure to a heating matrix, wherein first the connecting element is permanently connected to the coupling element, and in a subsequent step the connecting element is permanently connected to the surface of the support structure facing the heating matrix.

[0025] 25. Depending on the selected production process, the connecting element can first be connected to the free end of the coupling element. Here, if necessary, the possible position tolerances of the coupling element are transferred to the connecting element. This particularly applies to tolerances in the two first spatial directions. By correcting the insertion depth of the coupling element in the connecting element, it is already possible to compensate for tolerances in the third spatial direction.

[0026] 26. The coupling element is permanently connected to the connecting element by a suitable method. Subsequently, the connection on the support structure is carried out. Since the position tolerances have been transferred to the connecting element, it may occur here that the connecting element deviates from the originally planned connecting element position by these tolerances. This can be countered by designing the support structure wider in the area of the planned position of the respective connecting element.

[0027] 27. Preferably, the connecting element has a smooth surface facing the support structure, by means of which the connection on the support structure can be carried out in a simple manner.

[0028] 28. In this case, the opening width for inserting the coupling element only needs to be slightly larger than the free end of the coupling element, since the tolerance compensation is only carried out in the third spatial direction here, and subsequently the compensation in the two first spatial directions is carried out by changing the position of the connecting element relative to the support structure.

[0029] 29. In an alternative method, it is expedient to permanently connect the connecting element to the surface of the support structure facing the heating matrix in a first step, and to insert the coupling element into the connecting element and permanently connect it to the connecting element in a subsequent step.

[0030] 30. Alternatively, the connection of the connecting element to the support structure is carried out first. In this case, the net opening of the connecting element must be large enough to achieve tolerance compensation in two first spatial directions. Compensation in the third spatial direction is achieved by adjusting the insertion depth.

[0031] 31. Advantageous refinements of the invention are described in the dependent claims and in the following description of the figures. Description of the Figures

[0032] 32. The invention is explained in detail below with reference to the figures according to an embodiment. Shown in the figures are:

[0033] 33. Figure 1 A partial view of a support structure with a plurality of connecting elements, which are mounted at the support structure and have different positions relative to the support structure,

[0034] 34. Figure 2 A partial view of a support structure with a plurality of connecting elements, which are arranged at predefined positions at the support structure,

[0035] 35. Figure 3 A sectional view through two connecting elements each with a coupled element inserted therein, wherein the coupled element is fixed in the connecting element by clamping, and

[0036] 36. Figure 4 A coupled element received in a cup-shaped chamber on both sides. Detailed Description of the Invention

[0037] 37. Figure 1 Shown is a support structure 1, which has a plurality of connecting elements 3 on one of its crossbeams 2. A coupled element 4 can be inserted into each of the connecting elements 3. The support structure 1, the connecting elements 3 and the coupled element 4 can be permanently connected to each other by means of a soldering process.

[0038] 38. In the example of Figure 1 , the connecting element 3 is first connected to the coupled element 4, which in turn is inserted into a unit of the heating substrate and connected to the heating substrate. The positional tolerance resulting from the production-related tolerances of the heating substrate is transmitted to the connecting element 3 via the coupled element 4. Thus, the connecting element 3 (as shown here, at the middle connecting element 3) is not centered on the crossbeam 2, but is sometimes slightly offset from its center.

[0039] 39. Figure 2Shows the connecting element 5 on the crossbeam 2 of the support structure 1. The connecting element 5 has an oblong opening that enables tolerance compensation in one of two first spatial directions. The connecting element 5 is first connected to the crossbeam 2 of the support structure 1, and only then is the coupling element 4 inserted into the connecting element. Thus, the connecting elements 5 are also very evenly distributed on the crossbeam 2.

[0040] 40. Figure 3 Shows a sectional view through the coupling element 4, which is inserted into the connecting element 6 on one side. The coupling element 4 is connected to the connecting element 6 by clamping. This can be a primary fixation, and subsequently a permanent connection is established by soldering.

[0041] 41. Figure 4 Shows the coupling element 4 inserted into the hollow cylindrical receiving part 7 on both sides. Here, position tolerances, especially in the third spatial direction, can be compensated for by changing the insertion depth.

[0042] 42. The different features of the individual embodiments can also be combined with each other.

[0043] 43. Figures 1 to 4 The embodiments of [the invention] are not particularly restrictive and are used to illustrate the idea of the present invention.

[0044] List of reference numerals:

[0045] 1 Support structure

[0046] 2 Crossbeam

[0047] 3 Connecting element

[0048] 4 Coupling element

[0049] 5 Connecting element

[0050] 6 Connecting element

[0051] 7 Hollow cylindrical receiving part

Claims

1. A support structure (1) for positioning a heating matrix in an exhaust section spatially delimited by a housing, wherein, The heating substrate is formed by a honeycomb body having a plurality of flow channels that can be flowed through along the main flow-through direction. Among them, the heating substrate is supported by a support structure (1) relative to the inner surface of the housing, and the heating substrate is fixed relative to the support structure (1) by means of a plurality of coupling elements (4). The coupling elements (4) are inserted into each unit formed by the flow channels of the heating substrate and are permanently connected to the unit. It is characterized in that the free end portions of the coupling elements (4) are directly or indirectly connected to the support structure (1) respectively, and tolerance compensation elements are respectively provided, and the tolerance compensation elements compensate for the position tolerances of the coupling elements (4) in at least two spatial directions.

2. The support structure (1) according to claim 1, characterized in that, The support structure (1) has cup-shaped chambers that are open towards the heating structure on its surface facing the heating substrate, and these cup-shaped chambers are respectively designed to receive the free ends of the coupling elements (4) and form tolerance compensation elements.

3. The support structure (1) according to claim 2, characterized in that, The net opening width of the cup-shaped chambers is respectively multiple times the cross-section of the free end of the coupling element (4).

4. The support structure (1) according to any one of claims 2 or 3, characterized in that, The depth of the cup-shaped chamber is greater than the average insertion depth of the coupling element (4).

5. The support structure (1) according to claim 1, characterized in that, Connecting elements (3, 5, 6, 7) are respectively arranged between the support structure (1) and the coupling element (4) as tolerance compensation elements. The connecting elements are permanently connected to the support structure (1) on one side and receive the free ends of the coupling elements (4) on the other side.

6. The support structure (1) according to claim 5, characterized in that, The connecting elements (3, 5, 6, 7) have openings facing the coupling element, and the openings are larger than the cross-section of the free end of the coupling element (4).

7. The support structure (1) according to any one of claims 5 or 6, characterized in that The connecting element (5) has an elongated hole-shaped opening.

8. A method for connecting a support structure (1) according to any one of claims 5 to 7 to a heating substrate, characterized in that, First, the connecting elements (3, 7) are permanently connected to the coupling element (4), and in a subsequent step, the connecting elements are permanently connected to the surface of the support structure (1) facing the heating substrate.

9. A method for connecting a support structure (1) according to any one of claims 5 to 7 to a heating substrate, characterized in that, In a first step, the connecting elements (5, 6, 7) are permanently connected to the surface of the support structure (1) facing the heating substrate, and in a subsequent step, the coupling element (4) is inserted into the connecting elements (5, 6, 7) and the coupling element is permanently connected to the connecting elements.

Images