Method for manufacturing an electrical feedthrough and electrical feedthrough

Abstract

The invention provides a method for producing an electrical feedthrough having a one- or multi-part inner conductor which is arranged at least sectionally in a metal outer tube and is electrically insulated from the outer tube by means of an electrically insulating material, wherein the inner conductor of the electrical feedthrough produced has at least one contact section which protrudes from the metal outer tube, wherein in the method the metal outer tube, the electrically insulating material and the section of the one- or multi-part inner conductor which is already arranged in the metal outer tube are compacted into an assembly with one another, wherein the at least one contact section which protrudes from the metal outer tube is joined to the one- or multi-part inner conductor only after the compacting of the metal outer tube, the electrically insulating material and the section of the one- or multi-part inner conductor which is already arranged in the metal outer tube into an assembly with one another has been completed, wherein the contact section is positioned such that it is oriented along the central axis of the metal outer tube.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing an electrical feeder and an electrical feeder. Background Technology

[0002] Electrical feeders are particularly needed when an electrical conductor needs to pass through a conductive material without electrical contact between the conductor and the conductive material. An electrical feeder typically consists of an electrical conductor, an insulating material that provides electrical insulation, and a sheath through which a connection is established with the conductive material through which the conductor passes.

[0003] There are a range of applications, such as in the automotive industry, where such feedthroughs are exposed to very high loads. If we consider, as an example, an electric exhaust heater for a catalytic converter in a motor vehicle, the power supply to the exhaust heater must be guided in an insulated manner through the wall of the pipe delivering the exhaust.

[0004] This type of catalytic converter heater is typically suspended in the exhaust pipe in a manner that isolates it from the exhaust pipe. This is accomplished partly by insulating pins inside the exhaust pipe, but at least in part by establishing a mechanical connection, particularly by welding or brazing, to a conductor protruding into the pipe through which the electrical feeder protrudes.

[0005] Furthermore, the electrical conductors of feedthroughs typically have threads on their connection side for securing electrical contacts with screw connections on the contact surfaces. In addition to pressure and tension, a considerable torsional force is at play when tightening and loosening this connection.

[0006] In other words, under such application conditions, the electrical feeder must withstand high temperature loads, high vibration loads, impacts, and mechanical shocks continuously and over long periods. Therefore, it is crucial that the electrical feeder possesses high tensile strength and high torsional strength.

[0007] To manufacture such an electrical feedthrough, it is known in the prior art to provide an electrical conductor, which may be made of, for example, NiCr8020, as an intermediate part shaped to the desired form, for example by turning, milling, and / or thread rolling. An insulating tube, typically made of a ceramic insulating material, is then pushed onto the conductor, particularly a porous MgO body made of, for example, C820. This device is then housed within the inner cavity of an outer tube, which may be made of, for example, stainless steel. After the device comprises the electrical conductor, the insulating tube, and the outer tube, it is compacted, particularly pressed, in a manner that reduces its cross-section, thereby producing the electrical feedthrough.

[0008] Another method known according to DE10 2012 110 098 B4 is to provide an electrical feeder comprising an inner conductor, an insulating material, and an outer tube as a compacted preformed rod material, and machining an exposed conductor segment of the inner sheath from the rod material as a contact and having a desired outer profile, for example by threading into the inner conductor machined from the rod material.

[0009] Practice has shown that a decisive problem arises in the manufacture of the two types of electrical feeders mentioned above, which ultimately stems from the following: during pressing or compaction, very high pressures must be applied in order to achieve the desired mechanical strength and low leakage rate, especially the leakage rate of exhaust through the electrical insulation material, while the electrical insulation material, even if it is optionally used as the molded body, represents a porous initial material whose porosity must be significantly reduced.

[0010] It has been proven difficult to achieve precise and reliable positioning of the inner conductor within the outer conductor after compaction. Whether compacting a single component for a feedthrough or compacting the inner conductor, insulation, and outer tube into a rod, even if the inner conductor is perfectly parallel and concentrically oriented with the outer tube before compaction—which is not always the case in mass production—the same position and orientation of the inner conductor no longer exist after compression; instead, there is a directional offset that can vary depending on the type of feedthrough or the type of rod being manufactured. This offset can easily reach the order of a few tenths of a millimeter to several millimeters, and in particular, it means that the minimum insulation distance requirement can only be met if such a large structural configuration is chosen so that the minimum insulation distance is always observed even if this offset occurs. Summary of the Invention

[0011] Therefore, the object of the present invention is to provide an improved method for manufacturing an electrical feeder and an improved electrical feeder, thereby ensuring the precise positioning of the electrical contacts of the inner conductor. This object is achieved by a method having the features of the present invention and an electrical feeder having the features of the present invention. Advantageous designs of the method or the electrical feeder are also the subject of the present invention.

[0012] The method according to the invention is used to manufacture an electrical feeder having a one-piece or multi-piece inner conductor that is at least partially arranged in a metal outer tube and electrically insulated from the outer tube by an electrical insulating material.

[0013] Typically, like a tube, the outer tube can be defined by a central axis defining its extension and a tube cross-section extending perpendicular to that central axis. In principle, the direction of the central axis can vary along the length of the tube (e.g., when the tube is bent into a siphon shape), and the tube cross-section can also vary along the length of the tube (e.g., when the tube tapers). However, in typical feedthroughs, tubes with a cylindrical geometry are used in most cases, where the tube cross-section is circular or annular and the central axis is predetermined by a straight line extending through the center point of the circle or annulus. Therefore, in cases where unclear, when referring to the central axis of the outer tube, it refers to the central axis of the inner cavity of the tube.

[0014] Here, the inner conductor of the fabricated feedthrough has at least one contact section protruding from the outer metal tube, which serves as an electrical contact or connection to the feedthrough. In many cases, this contact section can be, for example, a cylindrical connecting end, a connecting tap, or a connecting pin, but in principle, it can also have other forms, and the connecting end may be provided with optional threads.

[0015] In this method, a metal outer tube, an electrical insulating material, and sections of one or more inner conductors arranged within the metal outer tube are pressed or compacted together to form an assembly. This requires at least one pressing or compaction step, which can be achieved, in particular, by pressing, hammering, rolling, or kneading. Specifically, magnesium oxide has proven to be an electrical insulating material that can be used as a molded body, powder, or granules and initially has a certain porosity, which must be significantly reduced during compaction to minimize the possible leakage rate through the feedthrough, especially the leakage rate of venting. For this purpose, high pressure is required, which causes deformation of the outer tube and inner conductor, particularly a reduction in the diameter and elongation of the respective materials.

[0016] Crucially for this invention, at least one contact segment protruding from the outer metal tube is only joined to the one-piece or multiple-piece inner conductor after the outer metal tube, electrical insulation material, and segments arranged in the outer metal tube within the one-piece or multiple-piece inner conductor have been compacted into an assembly, wherein the contact segment is positioned such that it is oriented along the central axis of the outer metal tube.

[0017] This method is based on the inventors' discovery that the pressing or compression process necessary for the compaction assembly, consisting of an outer tube, an inner conductor, and electrical insulation material, causes an irreproducible variation in the position of the inner conductor within the outer tube, varying depending on the feedthrough. According to the invention, by engaging the contact segment only after pressing or compaction is complete, it is ensured that the contact segment is accurately positioned relative to the outer tube at the desired location. However, it should be noted that this excludes pressed contact between the contact segment and the inner conductor, because without engaging the contact segment after pressing or compaction, unpredictable positional changes would occur again when establishing pressed contact.

[0018] According to a first embodiment of the method, before joining the contact segments, but after completing the compaction of the metal outer tube, electrical insulation material, and segments of the one-piece or multi-piece inner conductor arranged in the metal outer tube into an assembly, the position of the inner conductor relative to the outer tube is determined, and this determination is used to position the contact segments. For this position determination, it may only be necessary to determine the position of the inner conductor relative to the outer tube at both ends. This can be used to determine the offset and / or tilt of the columnar portion of the inner conductor arranged in the metal outer tube, which is in most cases substantially columnar, and is the most common positional change of the inner conductor during compaction or pressing.

[0019] Alternatively or additionally, the position of the central axis of the outer tube can be determined before joining the contact segments, but after the assembly is completed by compacting the metal outer tube, electrical insulation material, and segments arranged in one or more inner conductors within the metal outer tube, and this determination can be used to position the contact segments. This method takes advantage of the fact that, under normal circumstances, the connection established between the outer tube and the wall through which the electrical feeder passes predetermines the position and orientation of the feeder, and thus represents a very suitable reference position for placing the contact segments.

[0020] The contact segment can be joined by machining a portion from a one-piece or multi-piece inner conductor. Specifically, this is because a one-piece inner conductor (since the contact segment should by definition be part of the inner conductor) can be realized, which can be formed from a rod made of conductive material. The contact segment can be added to this rod, for example, using a machining process. It is important to note that these processes must be performed relative to a central axis that is offset from the central axis of the inner conductor, particularly coinciding with the central axis of the outer tube, in order to compensate for positional shifts of the inner conductor that occur during compaction into an assembly. This also means using an inner conductor with a cross-section that is chosen to be excessively large, so as to compensate for the maximum displacement that occurs during pressing or compaction into an assembly.

[0021] In particular, it is also possible to expose the contact sections of one-piece or multi-piece inner conductors by removing the compacted parts of the outer metal tube and electrical insulation material in advance, that is, to cause the inner conductor to protrude afterward.

[0022] Alternatively, the contact segments can be joined by connecting individual segments to (which must be multi-piece) the inner conductor, or more precisely, to the location where the segment is to be located according to the design. For this purpose, the contact segments can be welded or brazed to the end of the portion of the one-piece or multi-piece inner conductor that is at least partially located inside the outer tube.

[0023] However, it is also possible to introduce a portion of the contact segment into an opening, for example, drilled or machined, on the end side of a portion of the inner conductor that is at least partially disposed within the outer tube, and weld or braze there. In an improved embodiment of this variant, a hole can be used that passes through the inner conductor but does not include the contact segment, particularly the complete section of the inner conductor located within the outer tube. The contact segment can then be provided as a separate component, together with the contacts at both ends, and pushed into the hole. However, it must then be ensured, by suitable means such as welding or brazing, that the feedthrough still has a low leakage rate, particularly the venting leakage rate, for example, less than tens of milliliters per minute at 0.3 bar. This requirement also results in the practical technical exclusion of pressure contact, because the applied pressing pressure is so high that the inner conductor deforms or displaces again, and the contact segment is only no longer attached to the inner conductor after the entire pressing or compaction to be performed is completed.

[0024] The electrical feeder according to the invention has a one-piece or multi-piece inner conductor, at least partially arranged in a metal outer tube and electrically insulated from the outer tube by an electrical insulating material. The inner conductor of the manufactured electrical feeder has at least one contact section protruding from the metal outer tube. Here, the metal outer tube, the electrical insulating material, and the sections of the one-piece or multi-piece inner conductor arranged in the metal outer tube are pressed or compacted together to form an assembly.

[0025] Crucially for this invention, the central axis of the inner conductor extends offset relative to the central axis of the outer tube, and the contact segment is offset relative to the central axis of the inner conductor and centered on the central axis of the outer tube. This measure ensures that the contact segment is correctly positioned at its target location.

[0026] In the first variant, the contact segment is machined from a segment of a one-piece or multi-piece inner conductor, thereby integrally connecting the contact segment with that segment of the inner conductor.

[0027] Alternatively, the contact section is a separate section that is brazed or welded to the rest of the inner conductor. Here, a portion of the contact section may be introduced into an opening on the end side of a portion of the one-piece or multi-piece inner conductor that is at least partially disposed within the outer tube and welded or brazed there. Attached Figure Description

[0028] The invention will now be described in more detail with reference to the accompanying drawings, which illustrate embodiments. In the drawings:

[0029] Figure 1 The side of the compacted assembly manufactured in the first step of the method for manufacturing an electric feeder is shown;

[0030] Figure 2 Showing will Figure 1 The components in the middle are further processed into a first variant of an electrical feeder;

[0031] Figure 3 Showing will Figure 1 The components in the middle are further processed into a second variant of an electrical feedthrough component;

[0032] Figure 4a After showing the first step of the third variant example of further processing the component into an electrical feedthrough, Figure 1 Longitudinal section of the middle component;

[0033] Figure 4b A schematic diagram showing the second step of a third variation of the process of further processing the component into an electrical feedthrough; and

[0034] Figure 4c The side of an embodiment of the electrical feeder thus obtained is shown. Detailed Implementation

[0035] Figure 1 The compaction assembly 1 is shown, which has a metal outer tube 10, an electrical insulating material 20, and an inner conductor 30. Upon closer inspection... Figure 1 Especially when viewed from the observer's perspective, a direct comparison of the positions of the inner conductor 30's central axis from point M to the outer tube 10's central axis A reveals that, after compaction, the inner conductor 30 does not extend centered within the outer tube 10, but rather shifts or tilts relative to it. This can be caused, for example, by errors in the inner conductor 30's positioning within the outer tube 10, such as parallel shifts or tilts, even before the compaction step, or by the inhomogeneity of the electrical insulation material 20 during compaction, and exists to varying degrees of severity; even if it is normally present, it is clearly exaggerated here. Simultaneously, the positional deviation of the inner conductor 30 from its ideal position can also be identified by the fact that the layers of the electrical insulation material 20 have different thicknesses in different radial directions.

[0036] Figure 2 The diagram shows a longitudinal section of the end region of an electrical feeder 100 manufactured from such component 1 according to the first method. The electrical feeder 100 has an outer tube 10, an electrical insulating material 20, and a one-piece inner conductor 30, wherein the electrical insulating material 20 is implemented here as magnesium oxide particles.

[0037] Feeder 100 is from Figure 1 The compacted component 1 shown is manufactured by removing the outer tube 10, electrical insulation material 20, and inner conductor 30 using tool 2. Figure 2The area indicated by the dashed line is used to expose the contact section 31. Upon observation of the contact section 31, it is immediately apparent that, unlike the prior art, the contact section 31 is not centered relative to the cylinder within the outer tube 10 that has not been removed relative to the inner conductor 30, but rather centered relative to the outer tube 10. Thus, despite compaction, the contact section 31 is positioned correctly and therefore allows for accurate contact.

[0038] Figure 3 The diagram shows a longitudinal section of the end region of an electrical feeder 200 manufactured from such component 1 according to the second method. The electrical feeder 200 has an outer tube 10, an electrical insulating material 20, and a multi-piece inner conductor 30. The multi-piece inner conductor 30 is formed by an inner conductor arranged within the outer tube 10 and separately manufactured contact sections 32 connected to the outer tube by brazing or soldering contact points 33. In other words, the feeder 200 is constructed such that... Figure 1 The compacted component 1 shown is manufactured by brazing or welding the prefabricated contact section 32 to the end of the section in which the inner conductor is arranged inside the outer tube 10.

[0039] Similarly, it is immediately apparent upon observation of the contact section 32 that, unlike the prior art, the contact section 32 is not centered relative to the cylinder arranged within the unremoved section of the outer tube 10 relative to the inner conductor 30, but rather centered relative to the outer tube 10, so that despite compaction, the contact section 32 is positioned correctly and thus can make accurate contact.

[0040] Figures 4a to 4c The different stages of manufacturing the electrical feeder 300 from this component 1 according to the third method are shown from different perspectives, with one end region in Figure 4c As shown, the electrical feeder 300 has an outer tube 10, an electrical insulating material 20, and a multi-piece inner conductor 30, which is formed by a section of the inner conductor 30 completely arranged inside the outer tube 10 and a separately manufactured contact section 35.

[0041] like Figure 4a As shown, the opening 34 is introduced into the section where the inner conductor 30 is completely arranged within the outer tube 10, or more precisely, it is centered relative to the outer tube 10, not relative to the cylinder in which the inner conductor 30 is arranged within the outer tube 10 but relative to the outer tube 10 itself. This can be achieved, for example, by drilling a hole.

[0042] In this embodiment, a separately manufactured contact segment 35 having an annular groove (in which a solder ring 36 is arranged) is then introduced into the opening 34 and brazed there using solder from the solder ring 36, thereby producing a multi-piece inner conductor 30.

[0043] Figure 4cAn electrical feeder 300 is shown, having at least a portion of an inner conductor 30 disposed within a metal outer tube 10 and electrically insulated from the outer tube 10 by an electrical insulating material 20. The inner conductor 30 has a contact section 35 protruding from the metal outer tube 10. The metal outer tube 10, the electrical insulating material 20, and the portion of the inner conductor 30 completely disposed within the metal outer tube 10 are mutually compacted to form assembly 1. In particular, it can be seen that the central axis M of the inner conductor 30 extends offset and / or obliquely relative to the central axis A of the outer tube 10, and the contact section 35 is offset relative to the central axis M of the inner conductor 30 and centered on the central axis A of the outer tube 10, thereby precisely positioning the contact section 35.

[0044] Explanation of reference numerals in the attached figures:

[0045] 1 component

[0046] 2 tools

[0047] 10 outer tubes

[0048] 20 Electrical insulation materials

[0049] 30 Inner conductor

[0050] 31, 32, 35 contact section

[0051] 33 Brazing or welding contact points

[0052] 34 Opening

[0053] 36 Solder ring

[0054] 100, 200, 300 electrical feeders

Claims

1. An electrical feeder having a one-piece or multi-piece inner conductor, at least partially disposed within a metal outer tube and electrically insulated from the metal outer tube by an electrical insulating material, wherein, The inner conductor of the electrical feeder has a contact section protruding from the outer metal tube, wherein the outer metal tube, the electrical insulating material, and the section of the one-piece or multi-piece inner conductor, which is completely arranged in the outer metal tube, are mutually compacted into an assembly. The inner conductor's central axis is offset and extends obliquely relative to the central axis of the outer metal tube, and the contact section is offset relative to the central axis of the inner conductor and centrally arranged on the central axis of the outer metal tube. The contact section is machined from a section of the one-piece or multi-piece inner conductor, thus the inner conductor and the contact section are one piece.

2. The electrical feeder according to claim 1, characterized in that, The contact segment is a separate segment, which is brazed or welded to the rest of the inner conductor.

3. An electrical feeder having at least a portion of an inner conductor arranged within a metal outer tube and electrically insulated from the metal outer tube by an electrical insulating material, wherein, The inner conductor of the electrical feeder has a contact section protruding from the outer metal tube, wherein the outer metal tube, the electrical insulating material, and the section of the one-piece or multi-piece inner conductor completely disposed within the outer metal tube are compacted together to form an assembly, characterized in that the central axis of the inner conductor is offset and extends obliquely relative to the central axis of the outer metal tube, and the contact section is offset and centrally disposed relative to the central axis of the inner conductor on the central axis of the outer metal tube, wherein a section of the contact section is introduced into an opening on the end side of the portion of the one-piece or multi-piece inner conductor at least partially disposed within the outer tube and is welded or brazed to the one-piece or multi-piece inner conductor.

4. An electrical feeder for using a conductive material to allow an electrical conductor to pass through a wall in an insulating manner in a long-term and continuous high-temperature load environment, the electrical feeder comprising: A metal outer tube defining a central axis, the metal outer tube being configured to be fixed to the wall; An inner conductor extending along the central axis within the outer tube, the inner conductor defining a conductor central axis offset from the central axis; An electrically insulating material that electrically insulates the outer metal tube from the inner conductor, the electrically insulating material being radially spaced from the central axis between the outer metal tube and the inner conductor, the outer metal tube, the inner conductor, and the electrically insulating material being compacted together to form an assembly; and The contact position is fixed to the contact segment of the component, the contact position is located on the central axis, such that the contact segment is centered on the central axis, and the contact position is located at the exposed end of the inner conductor.

5. The electrical feeder according to claim 4, characterized in that, The outer metal tube is configured to be fixed to the wall by one of welding or brazing.

6. The electrical feeder according to claim 5, characterized in that, The wall is the wall of the exhaust pipe that delivers automobile exhaust.

7. The electrical feeder according to claim 4, characterized in that, The electrical insulating material is composed of magnesium oxide particles.

8. The electrical feeder according to claim 4, characterized in that, The contact segment is fixed to the component by one of brazing and welding.

9. The electrical feeder according to claim 4, characterized in that, The contact section includes a base end and a connecting end, the base end is fixed to the contact position, and the threaded end is separated from the contact position.

10. The electrical feeder according to claim 4, characterized in that, The inner conductor is one piece or multiple pieces and has a columnar section.

11. The electrical feeder according to claim 4, characterized in that, The contact segment protrudes from the exposed end of the component.

12. The electrical feeder according to claim 4, characterized in that, The inner conductor and the electrical insulating material are completely arranged inside the outer metal tube.

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