Feedthrough for an electric heating device, electric heating device with such a feedthrough, system with such a feedthrough and method for manufacturing such a feedthrough

Abstract

A penetration (10, 20, 30) for passing a connection for an electric heating device through a metal wall to supply the electric heating device with current, wherein the connection is part of the penetration (10, 20, 30) and is formed by a connecting conductor (11, 21, 31) which is electrically separated from an outer sheath (13, 23, 33) of the penetration, which is at least partially made of metal, by an electrically insulating material (12, 22, 32), wherein the connection has at least one exposed connecting conductor section (11a, 11b, 21a, 21b, 31a, 31b), wherein the outer sheath (13, 23, 33) has several outer sheath sections (13a, 13b, 23a, 23b, 23c, 33a, 33b) that are electrically insulated from one another in the direction of the connecting conductor (11, 21, 31), characterized in that the outer sheath (13, 23, 33) Metal sleeve with ring-shaped cutouts (13c,23d,23e,33c).

Description

[0001] Electric heating devices are widely used in a variety of applications. For many of these applications, it is necessary to position the electric heating device within a volume. This results in the problem that an electrical connection for supplying power to the electric heating device must be routed through the metal wall surface in an electrically insulated manner, which can be achieved using a bushing such as that known from WO 96 / 41 353 A1.

[0002] In a wide range of applications, such as in the automotive sector, this bushing is subjected to various, significant stresses from operating conditions and potential environmental influences. Accordingly, the bushing must exhibit sufficient mechanical stability, even under long-term vibration. At the same time, moisture ingress should be prevented as far as possible, and the necessary tracking resistance should be ensured. Extensively implementing these requirements presents a demanding technical challenge. This is particularly true because the already stringent requirements are further intensified when using higher vehicle electrical system voltages, such as 48V.

[0003] Further embodiments or methods for their manufacture are disclosed in DE 10 2012 110 098 A1, US 2010 / 0 038 131 A1, and US 5 318 756 A1. In particular, an embodiment with the features of the preamble of claim 1 is known from US 5 177 961 A.

[0004] This problem is solved by a feedthrough for an electric heating device with the features of claim 1, an electric heating device with the features of claim 8, a system with such a feedthrough with the features of claim 10, and a method for manufacturing such a feedthrough with the features of claim 13. Advantageous embodiments of the invention are the subject of the respective dependent claims.

[0005] The inventive feedthrough for passing a connection for an electric heating device through a metal wall to supply the electric heating device with current has a connection which is part of the feedthrough and is formed by a connecting conductor which is electrically separated from an outer sheath of the feedthrough which is at least partially made of metal by an electrically insulating material, wherein the connection has at least one exposed connecting conductor section in order to establish an electrical connection.The connecting conductor can be, for example, a connecting wire or connecting bolt with which electrical contact is established only on the side of the metal wall on which the electrical heating device is located; however, it can also be a connecting wire or connecting bolt that is led out of the electrical heating device, so that the feedthrough and the electrical heating device form a coherent system from the outset.

[0006] A key feature of the invention is that the outer sheath comprises several electrically insulated outer sheath sections in the direction of the conductor. In certain embodiments, it can also consist of these outer sheath sections.

[0007] According to the invention, a sheathing tube, which is divided into tube segments by cutouts, forms the outer sheath with several outer sheath sections that are electrically insulated from each other in the direction of the conductor.

[0008] This measure achieves a significant increase in tracking resistance by increasing the air and creepage distances or, more generally, the insulation distance, while simultaneously ensuring the structural integrity of the penetration almost over its entire length.

[0009] Particularly preferably, such an outer sheath can be simply realized by a metal sleeve with annular recesses. These annular recesses can, in particular, have an undercut, which is especially advantageous when an electrically insulating material, in particular an electrically insulating sealant, is arranged in at least one area between two adjacent outer sheath sections, preferably filling this area with this material. This measure can significantly contribute to protecting the integrity of the electrically insulating material arranged between the connecting conductor and the outer sheath of the bushing and is often particularly advantageous when the bushing is used in damp and wet environments.However, it should also be emphasized that, in principle, the electrical insulation between the outer sheath sections can in many cases already be reliably ensured by an air gap in conjunction with the electrically insulating material between the outer sheath sections.

[0010] If one of the outer sheath sections, which are electrically insulated from each other in the direction of the conductor, is connected, preferably soldered or welded, to the metal wall through which the electrical connection passes, the fluid tightness of a container or pipe to the outside, to which the metal wall through which the pass-through leads, can be ensured, and a robust and long-term stable connection can be guaranteed even in systems that are subject to vibrations during operation.

[0011] It is particularly preferred if the electrically insulating material with which the connecting conductor is electrically separated from the outer sheath of the bushing, which consists at least partially of a metal, is compacted magnesium oxide, aluminum oxide, boron nitride, or a mixture of these materials. However, it can also be designed as a ceramic molded part or as a pressed part.

[0012] Especially in applications where the bushing may be exposed to moisture, it is advantageous if the electrically insulating material that electrically separates the connecting conductor from the bushing's outer sheath (which is at least partially made of metal) has water-repellent properties, at least in those sections. This is particularly important in sections where it is not covered by the outer sheath, such as in the area of ​​an end face of the bushing and / or in the areas where electrical insulation is established between different sections of the outer sheath. This can be achieved, in particular, by impregnating or potting the electrically insulating material with a potting compound in the sections where it has water-repellent properties.

[0013] The electrical heating device according to the invention is characterized by a design according to the invention, which can in particular also be further developed in one of the ways described above.

[0014] The system according to the invention comprises a feedthrough according to the invention, which may in particular also be further developed in one of the ways described above. A further essential component of the system is a metal wall through which the feedthrough passes and to which the feedthrough is connected, in particular by welding or soldering.

[0015] In many cases, systems are particularly preferred in which the metal wall is the wall of a container or pipe and in which the connection is electrically conductive to an electric heating device located inside the container or pipe. The electric heating device can be, in particular, a heating cartridge, a tubular heating element, or a coiled heating element, but also a directly energized structure, especially a metal or honeycomb structure. A feedthrough with indentations can also be an integrated component of a heating cartridge and, in particular, form part of the unheated area at the connection of the heating cartridge.

[0016] The inventive method for producing an inventive embodiment comprises in particular the steps - Providing a feedthrough for passing a connection for an electric heating device through a metal wall to supply the electric heating device with current, wherein the connection is part of the feedthrough and is completely electrically separated in the direction of the connection by an electrically insulating material from an outer metal sheath of the feedthrough, which surrounds the electrically insulating material radially over its entire extent, and - Dividing the outer sheath into several electrically insulated outer sheath sections in the direction of penetration.

[0017] With this approach, it is particularly possible for the connecting conductor, the electrically insulating material, and the outer sheath, which together form the bushing, to be supplied as compacted bar stock. The outer sheath is preferably divided into several electrically insulated sections in the bushing direction by machining.

[0018] In a further development of the method, advantageous for a number of applications, the space between at least two outer sheath sections that are electrically insulated from each other in the feedthrough direction is filled with an electrically insulating material, in particular an electrically insulating sealant. In this way, the electrically insulating material, which is relatively sensitive to mechanical stress and isolates the connecting conductor from the outer sheath of the feedthrough, can also be protected in these areas, and the sensitivity of the feedthrough to moisture in the application environment can be reduced.

[0019] It is particularly preferred if the exposed connecting conductor section is also produced by machining. In particular, it can be structured, e.g., by a thread. In this case, it is considered advantageous if the exposed connecting conductor section is also structured by machining.

[0020] A further reduction in the sensitivity of a feedthrough produced in this way can be achieved by impregnating or potting the electrically insulating material in at least one of the sections that are not located inside the outer sheath.

[0021] The invention is explained in more detail below with reference to figures illustrating exemplary embodiments. These show: Fig. 1: a first embodiment of a feedthrough in a partially opened representation, Fig. 2: a second embodiment of a feedthrough in a partially open representation, Fig. 3: a third embodiment of a feedthrough in a partially open representation, and Fig. 4: a magnification of a detail from Fig. 3.

[0022] Fig. Figure 1 shows a feedthrough 10 for routing a connection for an electric heating device (not shown) through a metal wall. The connection is permanently attached to the feedthrough 10; thus, it is an integral part of the feedthrough, and its components are also components of the feedthrough 10.

[0023] The connection is made in the exemplary embodiment according to the Fig. 1 formed by a connecting conductor 11, which is electrically separated from an outer sheath 13 of the bushing, at least partially made of metal, by an electrically insulating material 12, e.g., a ceramic molded part or compressed magnesium oxide, aluminum oxide, or mixtures containing these components. The connection, and thus the bushing 10, has two exposed connecting conductor sections 11a and 11b. Here, for example, a thread has been cut into connecting conductor section 11a by machining, so that an electrical connection is made possible by screwing on a suitably designed connector (not shown here). The electrical connection of connecting conductor section 11b, which in this example is intended for the electrical contacting of an electrical heating device (not shown), can be, for example,Connections can be made by crimping, soldering or welding; a plug connection is also possible in principle.

[0024] Compared to known implementations of this type, a special feature of the one in Fig. As shown in Figure 1, the outer sheath 13 has several electrically insulated outer sheath sections 13a, 13b in the direction of the connecting conductor 11, i.e., the direction in which the current is intended to flow in the connecting conductor 11. These sections are electrically separated from each other by the annular recess 13c and the air gap created by it. In this embodiment, the outer sheath even consists of these outer sheath sections.

[0025] This improves the tracking resistance of the bushing; in contrast to a solution in which the “naked” electrically insulating material 12 protrudes beyond the outer sheath 13, significantly better mechanical stability and reduced sensitivity to moisture are achieved.

[0026] The in Fig. The shown configuration 20 consists of a connecting conductor 21, which is electrically separated from the outer metal sheath 23 by the electrically insulating material 22. A first significant difference to the one in Fig. The difference in the implementation shown in Figure 10, described above, lies in the different design of the exposed conductor sections 21a and 21b. Specifically, conductor section 21a has an internal thread cut into its end face, and conductor section 21b is shaped like a connector pin tapering towards the end face. This illustrates some of the many design freedoms available for the specific creation of the electrical connection to the terminal or feedthrough.

[0027] A second key difference is that the outer sheath 23 has three outer sheath sections 23a, 23b, 23c, which are electrically separated and thus insulated from one another in the direction of the connecting conductor 21 by the annular recesses 23d, 23e and the air gap created by them. In this way, relatively long distances can be achieved without significant loss of mechanical stability or substantial reduction in moisture resistance.

[0028] The in Fig. 3 and the associated enlarged section according to Fig. The penetration 30 shown in Figure 4 is identical to penetration 10 with respect to the connecting conductor 21 with connecting conductor sections 21a, 21b and the electrically insulating material 22. Fig. 1, but exhibits 33 deviations with regard to the design of the outer shell. Although this is similar to that in Fig. 1, divided by the annular recess 33c into two metallic outer shell sections 33a, 33b, as can be seen particularly well in the magnification of detail Z in Fig. As can be seen in Figure 4, the ring-shaped recess 33c has an undercut and is filled with an electrically insulating material 36, for example a ceramic putty. This significantly increases mechanical stability and moisture resistance. Reference symbol list 10, 20, 30 Implementation 11, 21, 31 Connection conductor 11a, 11b, 21a, 21b, 31a, 31b Connection conductor section 12, 22, 32 electrically insulating material 13, 23, 33 Outer shell 13a,13b,23a,23b,23c,33a,33b Outer shell section 13c, 23d, 23e, 33c Cutout 36 electrically insulating material Z Detail

Claims

[1] A penetration (10, 20, 30) for passing a connection for an electric heating device through a metal wall to supply the electric heating device with current, wherein the connection is part of the penetration (10, 20, 30) and is formed by a connecting conductor (11, 21, 31) which is electrically separated from an outer sheath (13, 23, 33) of the penetration which is at least partially made of metal by an electrically insulating material (12, 22, 32), wherein the connection has at least one exposed connecting conductor section (11a, 11b, 21a, 21b, 31a, 31b), wherein the outer sheath (13, 23, 33) has several outer sheath sections (13a, 13b, 23a, 23b, 23c, 33a, 33b) which are electrically insulated from one another in the direction of the connecting conductor (11, 21, 31), characterized by , that the outer sheath (13,23,33) has a metal sleeve with ring-shaped cutouts (13c,23d,23e,33c). [2] Implementation (10, 20, 30) according to claim 1, characterized by, that the ring-shaped cutouts (13c,23d,23e,33c) have an undercut. [3] Implementation (10, 20, 30) according to claim 1 or 2, characterized by , that in at least one area between two adjacent outer sheath sections (13a,13b,23a,23b,23c,33a,33b) an electrically insulating material (36), in particular an electrically insulating putty, is arranged. [4] Implementation (10, 20, 30) according to any one of claims 1 to 3, characterized by , that one of the outer sheath sections (13a,13b,23a,23b,23c,33a,33b) which are electrically insulated from each other in the direction of the connecting conductor (11,21,31) is connected, preferably soldered or welded, to the metal wall through which the electrical connection is passed in the passage (10,20,30). [5] Implementation (10, 20, 30) according to any one of claims 1 to 4, characterized by, that the electrically insulating material (12,22,32) with which the connecting conductor (11,21,31) is electrically separated from the outer sheath (13,23,33) of the bushing (10,20,30) which is at least partially made of a metal, is compacted magnesium oxide, compacted aluminum oxide, compacted boron nitride, a compacted mixture of these materials, a ceramic molded part or a pressed part. [6] Implementation (10, 20, 30) according to any one of claims 1 to 5, characterized by , that the electrically insulating material (12,22,32) with which the connecting conductor (11,21,31) is electrically separated from the outer sheath (13,23,33) of the bushing (10,20,30) which is at least partially made of metal, has at least partially water-repellent properties. [7] Implementation (10, 20, 30) according to claim 6, characterized by, that the electrically insulating material (12,22,32) is impregnated or potted with a potting compound in the sections where it has water-repellent properties. [8] Electric heating device with a feedthrough (10,20,30) according to one of the preceding claims. [9] Electric heating device according to claim 8, characterized by , that the connecting conductor (11,21,31) of the feedthrough (10,20,30) - especially at the end face - is soldered or welded to a honeycomb structure, so that the honeycomb structure is suspended on the connecting conductor (11,21,31) of the feedthrough (10,20,30) insulated from the outer sheath (13,23,33) of the feedthrough (10,20, 30). [10] System comprising a feedthrough (10, 20, 30) according to one of claims 1 to 7 and a metal wall through which the feedthrough (10, 20, 30) passes and to which the feedthrough (10, 20, 30) is connected, in particular welded or soldered. [11] System according to claim 10, characterized by, that the metal wall is the wall of a container or pipe and that the connection is electrically conductive to an electrical heating device arranged in an interior of the container or pipe, in particular a heating cartridge, a tubular heating element, a tubular coil cartridge or a directly energized structure, in particular a metal or honeycomb structure. [12] System according to claim 11, characterized by , that the connecting conductor (11,21,31) of the feedthrough (10,20,30) - especially at the end face - is soldered or welded to a honeycomb structure, so that the honeycomb structure is suspended on the connecting conductor (11,21,31) of the feedthrough (10,20,30) insulated from the outer sheath (13,23,33) of the feedthrough (10,20, 30). [13] Method for producing a feedthrough (10, 20, 30) Feedthrough (10, 20, 30) for passing a connection for an electric heating device through a metal wall to supply the electric heating device with current, wherein the connection is part of the feedthrough (10, 20, 30) and is formed by a connecting conductor (11, 21, 31) which is electrically separated from an outer sheath (13, 23, 33) of the feedthrough which is at least partially made of metal by an electrically insulating material (12, 22, 32), wherein the connection has at least one exposed connecting conductor section (11a, 11b, 21a, 21b, 31a, 31b), wherein the outer sheath (13, 23, 33) has several outer sheath sections (13a, 13b, 23a, 23b, 23c, 33a, 33b) which are electrically insulated from one another in the direction of the connecting conductor (11, 21, 31), with the steps - Providing a feedthrough (10, 20, 30) for passing a connection for an electric heating device through a metal wall to supply the electric heating device with current, wherein the connection is part of the feedthrough (10, 20, 30) and is completely electrically separated in the direction of the connection by an electrically insulating material (11, 21, 31) from a metal outer sheath (13, 23, 33) of the feedthrough (10, 20, 30) by an electrically insulating material (12, 22, 32), which surrounds the electrically insulating material (12, 22, 32) in a radial direction over the entire extent of the electrically insulating material (12, 22, 32), and - Dividing the outer sheath (13,23,33) into several outer sheath sections (13a,13b,23a,23b,23c,33a,33b) that are electrically insulated from each other in the direction of penetration. [14] Method according to claim 13, characterized by, that the connection, the electrically insulating material (12,22,32) and the outer sheath (13,23,33), which together form the feedthrough (10,20,30), are provided as compacted rod material. [15] Method according to claim 13 or 14, characterized by , that the division of the outer sheath (13,23,33) into several outer sheath sections (13a,13b,23a,23b,23c,33a,33b) electrically insulated from each other in the direction of passage is carried out by machining. [16] Method according to any one of claims 13 to 15, characterized by that the space between at least two outer sheath sections (13a,13b,23a,23b,23c,33a,33b) that are electrically insulated from each other in the direction of passage is filled with an electrically insulating material (36), in particular an electrically insulating putty. [17] Method according to any one of claims 13 to 16, characterized by, that the exposed connecting conductor section (11a,11b,21a,21b, 31a,31b) is produced by machining. [18] Method according to any one of claims 13 to 17, characterized by , that the exposed connecting conductor section (11a,11b,21a,21b, 31a,31b) is structured by machining. [19] Method according to any one of claims 13 to 17, characterized by , that the electrically insulating material (12,22,32) is impregnated or potted with a potting compound in at least one of the sections that are not located inside the outer sheath (13,23,33).

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