Heating element with spacer

Abstract

Heating element (10) comprising the following: a heating resistor (1) for insertion into an exhaust pipe (4), and at least one inserted spacer element (3a, 3b, 3c); wherein: the heating resistor (1) has a basic shape_G with a central axis (1.4), one or more heating loops arranged side by side (1.3a, 1.3b, 1.3c) are formed, Each respective heating loop (1.3a, 1.3b) is formed from two adjacent sections (1.3), the two adjacent sections (1.3) define a groove (1.6) with a groove axis (1.6a), wherein the groove (1.6) serves to accommodate a spacer element (3a, 3b, 3c), at least one of the two adjacent sections (1.3) in addition to the groove (1.6) on the outer circumference of the basic form_G has a recess (1.9) with a flank (1.9a) into which the respective spacer element (3a, 3b, 3c) can be inserted, the respective spacer element (3a, 3b, 3c) can be brought into a positive fit with the respective flank (1.9a) in both directions with reference to the groove axis (1.6a); the respective spacer element (3a, 3b, 3c) and the respective heating loop (1.3a, 1.3b, 1.3c) are electrically insulated from each other; the respective spacer element (3a, 3b, 3c) can be inserted into the respective recess (1.9); and a) at least part of the spacer elements (3a, 3b, 3c) is designed in the form of a one-piece non-circular spacer element bridge (5), or b) the spacer elements (3a, 3b, 3c) are formed in the form of at least two or three non-circular spacer element bridges (5).

Description

[0001] The invention relates to a heating element for insertion into an exhaust pipe, wherein the heating element is formed in a shape with one or more adjacent heating loops, which form a basic shape_G with a central axis, or the heating element has a basic shape_G with a central axis in which several adjacent heating loops are formed, wherein the respective heating loop is formed from two adjacent sections, wherein adjacent sections define a groove with a groove axis, which serves to receive a spacer element.

[0002] An electrode with a spacer element is already known from WO 2014 73545 A1. The electrode has circumferential slots into which spacer elements are inserted.

[0003] Furthermore, DE 10 2021 131 370 A1 discloses a heating device for an exhaust system comprising an electrically conductive, foamed part and at least one stabilizing part for it. The foamed part has two end faces, an outer circumference, and at least one recess extending axially from the outer circumference from one end face to the other. The recesses create spaced-apart, opposing, and converging sections that form a current path as a resistance heating element. The stabilizing part at least partially fills the recess and mechanically, but not electrically, couples the sections together.

[0004] US 5 194 719 A concerns the reinforcement and assembly of thin-walled metal honeycomb structures, such as those that can be used as substrates or preheaters in the emission control of gasoline or diesel combustion engines.

[0005] Furthermore, US 5,501,842 A discloses an axially mounted housing for electric liquid heaters and an assembly method, wherein a metallic honeycomb heating element is secured in an axially mounted housing comprising opposing tubular housing sections with internal bore stops and an elastic fastening material for supporting the heating element. During assembly, an axial force of predetermined magnitude is applied to the sections, which pre-tensions the elastic fastening material and generates a selected spring tension and preload force on the honeycomb. The sections are then fastened together under this force, so that the preload force and spring tension are maintained during subsequent use of the assembly.

[0006] The present invention is aimed at overcoming one or more of the problems or disadvantages associated with the prior art. In particular, the invention is based on the objective of designing and arranging an electrode in such a way as to improve the insertion and seating of the spacer elements.

[0007] The object of the present invention is achieved by a heating element, a system, and a method for manufacturing a heating element according to the main claims. The dependent claims relate to preferred embodiments of the invention.

[0008] According to the invention, at least one of the two adjacent sections, in addition to the groove on the outer circumference of the basic form_G, has a recess with a flank into which the respective spacer element can be inserted, wherein the respective spacer element can be brought into a positive fit with the respective flank in both directions with respect to the groove axis. The groove axis is oriented perpendicular to the central axis or perpendicular to the flow axis of the exhaust gas stream to be heated. This makes it possible to insert any number of spacer elements, usually in the form of pins, into the heating element automatically. The respective pin has only this one translational degree of freedom with respect to the aforementioned mounting direction. The pins can be secured by means of corresponding mounting elements that are arranged adjacent to the heating element.

[0009] Furthermore, the spacer element and the respective heating loop or section or leg are electrically insulated from each other, wherein a) at least part of the spacer elements is designed in the form of a one-piece non-circular spacer element bridge, or b) the spacer elements are designed in the form of at least two or three non-circular spacer element bridges, whereby in both cases a) and b) the respective spacer element can be inserted into the respective recess. Unlike the bridge, in the case of separate components each spacer element is separate.

[0010] If the spacer elements form several separate components, the spacer elements are preferably made of an insulating material or a non-electrically conductive material such as ceramic, so that the respective spacer element and the respective heating loop are electrically insulated from each other.

[0011] If at least part of the spacer elements is designed in the form of a one-piece spacer bridge, the spacer bridge is preferably made of an insulating material or a non-electrically conductive material, such as ceramic or ceramic fibers, so that the respective spacer element and the respective heating loop are electrically insulated from each other.

[0012] In both cases, adjacent heating loops are also electrically isolated from each other by the respective spacer element. The spacer element ensures either the distance between heating loops, the distance between the electrode connection element and the heating element, or both distances. This prevents any noise disturbances during operation of the heating element, particularly those caused by resonance vibrations of the heating element or the heating loops. Furthermore, it prevents a short circuit between the respective electrode connection element and the heating element or the heating loops.

[0013] Furthermore, it can be advantageous if the recess has a cross-sectional shape F and the spacer element has a cross-sectional shape Q, wherein a) the cross-sectional shape F corresponds to a partial shape of the cross-sectional shape Q and / or b) the cross-sectional shape F and / or the cross-sectional shape Q is round, oval, polygonal, or rectangular. If the cross-sectional shape F corresponds to a partial shape of the cross-sectional shape Q, for example, a semicircular shape for a round cross-sectional shape Q, then a minimum contact pressure is ensured between the spacer element and the radiator.

[0014] It can also be advantageous if the respective spacer element can be inserted into the respective recess at a right angle or perpendicular to the groove axis, or if the respective spacer element can be inserted into the respective recess in a direction parallel to the central axis. Insertion or removal parallel to the groove axis is therefore not possible.

[0015] Advantageously, the heating element may have a ceramic or metallic honeycomb structure, wherein the ceramic honeycomb structure has an electrically conductive coating and / or the electrically conductive coating or the metallic honeycomb structure has a catalytic coating. In addition to heating, the heating element can also be used for catalytic cleaning of the exhaust gas.

[0016] The present invention further relates to a heating element with a heating resistor as described above and at least one inserted spacer element.

[0017] Furthermore, a system consisting of a heating element as described above and at least a part of an exhaust system in the form of an exhaust pipe can be advantageous, with the heating resistance being located inside the exhaust pipe.

[0018] Finally, a method for manufacturing a heating resistor is advantageous in which a) the respective spacer element is inserted into the respective recess in a direction perpendicular or transverse to the groove axis or b) The respective spacer element is inserted into the respective recess in a direction parallel to the central axis. Inserting or pre-assembling the pins can be accomplished easily, particularly automatically. The spacers can simply be inserted into the placed heating element. The number of spacers can vary from heating element to heating element. No adjustment of the geometry of the spacers or a spacer bridge is necessary.

[0019] Further advantages and details of the invention are explained in the patent claims and in the description and illustrated in the figures.

[0020] They show: Fig. 1 a heating element in perspective view; Fig. 2 a radiator according to Fig. 1; Fig. 3 the heating element mounted in an exhaust pipe; Fig. 4 another embodiment of the spacer elements; Fig. 5 an alternative embodiment of the spacer elements; Fig. 6a, Fig. 6b different embodiments of the honeycomb structure.

[0021] A in Fig. The heating element 10 shown in Figure 1 has a heating element in the form of a heating resistor 1. The heating resistor 1 has several heating loops 1.3a to 1.3c, each with a contact zone 1.1, 1.2 at its end, to which an electrode connection element 2.3, 2.4 is electrically connected. Each electrode connection element 2.3, 2.4 is in turn provided with an electrode 2.1, 2.2 for connection to an electrical system. Each heating loop 1.3a - 1.3c has two sections or legs 1.3, which are separated from each other by the groove 1.6. Adjacent legs 1.3 are thus separated from each other by the groove 1.6. A spacer element 3a to 3c is provided in the end region of the groove 1.6, which ensures the distance between adjacent heating loops 1.3a, 1.3b.

[0022] According to the exemplary embodiment Fig. 1 The respective spacer element 3a to 3c is a single component of the respective electrode connection element 2.3, 2.4. To prevent a short circuit between adjacent heating loops 1.3a, 1.3b, the respective electrode connection element 2.3, 2.4 has an insulating layer 2.8, which is provided in particular where the respective spacer element 3a to 3c or the electrode connection element 2.3, 2.4 has contact with the heating resistor 1.

[0023] Opposite the heating electrodes 2.1, 2.2, a spacer 5 designed as a bridge is provided, which also has corresponding spacer elements that are arranged in the end area of ​​the respective groove.

[0024] In Fig. Figure 2 shows the heating element 1 on its own. The heating element 1 has a round basic shape_G, which allows it to be mounted in a similarly round exhaust pipe 4 according to Fig. 3 ensures. The heating resistor 1 has an axis of symmetry 1.5, which is arranged perpendicular to a central axis 1.4. On the after Fig. On the left side, contact zone 1.1 is provided, and on the right side, contact zone 1.2 is provided. With respect to the respective contact zones 1.1 and 1.2, the heating resistor 1 exhibits a hinged symmetry K, such that contact zone 1.1 can be transformed into contact zone 1.2 by hinges around the axis of symmetry 1.5. Due to this hinged symmetry of the two contact zones 1.1 and 1.2, it is possible to use two electrode connection elements 2.3 with identical symmetry to connect both contact zone 1.1 and contact zone 1.2 as shown in Fig. 1 shown to be electrically connected to the respective electrode 2.1, 2.2.

[0025] In the detailed view after Fig. Figure 2 shows the end region of a groove 1.6 between two adjacent heating loops 1.3a, 1.3b. The groove 1.6 has a groove axis 1.6a and a recess 1.9 extending transversely to the groove axis 1.6a. This recess 1.9 creates a flank 1.9a, 1.9b on the respective heating loop 1.3a, 1.3b. The flanks 1.9a, 1.9b ensure a positive fit with the respective spacer element 3a to 3c in both directions along the groove axis (1.6a).

[0026] Example of implementation Fig. 3 The heating element 10 is arranged or mounted inside an exhaust pipe 4. The electrodes 2.1, 2.2 are led to the outside via the two electrode connection elements 2.3, 2.4. The respective heating loop 1.3a, 1.3b has the recess 1.9 with the respective flank 1.9a, 1.9b in which the respective spacer element 3a, 3b is received.

[0027] Example of implementation Fig. 4 also includes a spacer 5 designed as a bridge, which also has corresponding spacer elements 3a - 3c arranged within the respective recess 1.9. The spacer elements 3a - 3c of the bridge 5 are inserted into the respective recess 1.9 in the axial direction to the central axis 1.4. The electrode connection element can also be part of the heating resistor, and thus be sintered as a single component. In this case, the spacer elements can be arranged as shown. Fig. 4 must be trained.

[0028] Example of implementation Fig. In section 5, the round radiator 1 has only individual or separate spacer elements 3a - 3c in the form of pins. The respective pin 3a - 3c is inserted into the respective recess 1.9 of the radiator 1.

[0029] In the exemplary embodiment Fig. 6a, Fig. Figure 6b shows a honeycomb structure 11 of the heating resistor 1. After Fig. 6a The honeycomb structure 11 is formed from ceramic material and has an electrically conductive coating 1.7. In the exemplary embodiment Fig. 6b is provided in addition to the electrical coating 1.7 or, in the case of a honeycomb structure made of metal, in addition to this honeycomb structure, a catalytic coating 1.8 for the catalytic cleaning of the exhaust gas. Reference symbol list 1 radiator, heating element 1a surface 1.1 Contact zone 1.2 Contact zone 1.3a Heating loop 1.3b Heating loop 1.3c Heating loop 1.3 Section or leg of 1.3a-1.3c 1.4 Center axis 1.5 Axis of symmetry 1.6 Nut 1.6a Nut axis 1.7 electrical coating 1.8 catalytic coating 1.9 Exclusion 1.9a Flank of 1.3a 1.9b flank from 1.3b 2.1 Electrode 2.2 Electrode 2.3 Electrode connection element 2.4 Electrode connection element 2.5 Contact area 2.8 Insulation layer 3a Spacer element 3b Spacer element 3c spacer element 4 Exhaust pipe 5 spacers, bridge 10 heating elements 11 honeycomb structure G basic form K Folding symmetry

Claims

[1] Heating element (10) comprising: a heating resistor (1) for insertion into an exhaust pipe (4), and at least one inserted spacer element (3a, 3b, 3c); wherein: the heating resistor (1) has a basic shape_G with a central axis (1.4), one or more heating loops (1.3a, 1.3b, 1.3c) arranged next to one another are formed, each respective heating loop (1.3a, 1.3b) is formed from two adjacent sections (1.3), the two adjacent sections (1.3) define a groove (1.6) with a groove axis (1.6a), the groove (1.6) serving to receive a spacer element (3a, 3b, 3c), at least one of the two adjacent sections (1.3) has, in addition to the groove (1.6) on the outer circumference of the basic shape_G, a recess (1.9) with a flank (1.9a) into which the respective spacer element (3a, 3b, 3c) can be inserted, the respective spacer element (3a, 3b, 3c) can be brought into positive engagement with the respective flank (1.9a) in both directions with respect to the groove axis (1.6a); the respective spacer element (3a, 3b, 3c) and the respective heating loop (1.3a, 1.3b, 1.3c) are electrically insulated from one another; the respective spacer element (3a, 3b, 3c) can be inserted into the respective recess (1.9); and a) at least some of the spacer elements (3a, 3b, 3c) are designed in the form of a one-piece non-circumferential spacer element bridge (5), or b) the spacer elements (3a, 3b, 3c) are designed in the form of at least two or three non-circumferential spacer element bridges (5). [2] Heating element (10) according to claim 1, wherein the respective spacer element (3a, 3b, 3c) is a one-piece component of a respective electrode connection element (2.3, 2.4). [3] Heating element (10) according to claim 1 or 2, characterized bythat the recess (1.9) has a cross-sectional shape F and the spacer element (3a, 3b, 3c) has a cross-section Q, wherein a) the cross-sectional shape F corresponds to a partial shape of the cross-section Q and / or b) the cross-sectional shape F and / or the cross-section Q is round, oval, polygonal or square. [4] Heating element (10) according to one of the preceding claims, characterized by , that a) the respective spacer element (3a, 3b, 3c) can be inserted into the respective recess (1.9) in a direction perpendicular or transverse to the groove axis (1.6a) or b) the respective spacer element (3a, 3b, 3c) can be inserted into the respective recess (1.9) in a direction parallel to the central axis (1.4). [5] Heating element (10) according to one of the preceding claims, characterized bythat the heating resistor (1) has a ceramic or a metallic honeycomb structure (11), wherein the ceramic honeycomb structure (11) has an electrically conductive coating (1.7) and / or wherein the electrically conductive coating (1.7) or the metallic honeycomb structure (11) has a catalytic coating (1.8). [6] System consisting of a heating element (10) according to one of the preceding claims and at least part of an exhaust system in the form of an exhaust pipe (4), wherein the heating resistor (1) is arranged within the exhaust pipe (4). [7] Method for producing a heating element (10) according to one of claims 1 to 5, characterized by , that a) the respective spacer element (3a, 3b, 3c) is inserted into the respective recess (1.9) in a direction perpendicular or transverse to the groove axis (1.6a) or b) the respective spacer element (3a, 3b, 3c) is inserted into the respective recess (1.9) in a direction parallel to the central axis (1.4).

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