DE102012110098A1 - Method for manufacturing electrical feedthrough for motor vehicle, involves separating portion of bar material, where length of bar material corresponds to desired length of electric conductors of feedthrough to be manufactured - Google Patents

Abstract

The method involves removing insulant at portions (220) of a bar material (290), where the portions are separated from each other by length corresponding to desired length of outer pipes (230) of feedthrough to be manufactured. The length of the portions corresponds to a projection of electric conductors (210) relative to face surfaces. A portion of the bar material is separated, where length of the bar material corresponds to desired length of the electric conductors of the feedthrough to be manufactured.

Description

Electrical feedthroughs are particularly required when an electrical conductor is to be passed through an electrically conductive material, without an electrical contact between the electrical conductor and the electrically conductive material is formed. They usually have an electrical conductor, an insulating material which acts as an electrical insulator and a jacket via which the connection to the electrically conductive material through which the conductor is to be guided can be produced.

There are a number of applications, for example in the automotive industry, in which such bushings are exposed to very high loads. If, for example, an electric exhaust gas heater of a catalytic converter for a motor vehicle is considered, the power supply of the exhaust gas heater must be passed through the wall of the pipe in which the exhaust gas flows in isolation.

Such a catalyst heater is often isolated from the exhaust pipe suspended in this, which partly via insulating pins in the interior of the exhaust pipe, but at least partially by making a mechanical connection of the projecting into the pipe interior conductor of the electrical implementation, in particular by welding or soldering.

In addition, the electrical conductor of the bushing often has a thread on its connection side for producing an electrical screw connection. When tightening and loosening this connection in addition to pressure and train also considerable torsional forces. In this application, therefore, the electrical implementation must withstand long term and continuous on the one hand a high temperature load, on the other hand, but also a high vibration load. Therefore, it is very important that the electrical feedthrough has high tensile strength and high resistance to torsion.

For the manufacture of such electrical feedthroughs, it is known from the prior art to provide the electrical conductor, which can be made of NiCr8020, for example, as a half made by turning, milling and / or thread rolling into the desired shape, then an insulating tube, typically made of a ceramic insulating material, in particular of a porous MgO body of eg C820 is postponed and then placed in the interior of an outer tube, e.g. made of stainless steel can absorb. After this arrangement is composed of electrical conductor, insulating tube and outer tube, it is compacted cross-section reducing, in particular pressed, so that the electrical feedthrough arises.

Practice shows that this way of making electrical feedthroughs poses a number of problems, although it involves a great deal of effort, since each electrical feedthrough must be assembled and compacted individually. Namely, the degree of compression achieved thereby varies such that it decreases towards the ends of the outer tube of the electrical feedthrough. As a result, these areas have only a slight stabilizing effect against mechanical stress, in particular in the form of tension, torsion or vibration.

This is particularly of high relevance because the length of the outer tube is usually very small due to structural requirements in terms of space requirements.

Furthermore, it happens that insulating material breaks at end faces of the compressed insulating tube. This further reduces the area between the conductor and the insulating material as well as the insulating material and the outer tube so that the bushing is even less resistant to pressure, tension and torsion.

These problems can be alleviated, but not completely avoided, when pressing silicon discs, rubber hoses or similar parts are placed on the front surfaces. These generate a certain axial back pressure during compression, which increases the compression in the edge region and reduces the breaking of the insulating material.

However, there are also problems with regard to the precision of the geometry of the electrical conductor of the bushing that can be reliably achieved with this method of production. In many practical applications, as the electrical conductor of the implementation is not just a wire use, but rather a connection bolt is required, which has a certain connection geometry on one or both sides of the electrical feedthrough, for example, given a small distance tolerances length by which the electrical conductor must project beyond the end faces of the outer tube and insulating material and / or a predetermined shape to provide a contact with an electrical connection, such as a thread.

Problems associated with the given form of electrical connection arise in prior art manufacturing, in particular because rotating the often very soft conductor material is a difficult process.

Problems in the maintenance of distance tolerances prepares in particular the process step of compression. In this process, there is an elongation of the material, which can cause the distance tolerances are not achieved reliably, so that a significant proportion of rejects is produced.

The object of the invention is therefore to develop an improved method for producing electrical feedthroughs. This object is achieved by a method having the features of claim 1. Advantageous embodiments of the method are the subject of the dependent claims.

• a) Bereitstellen eines Außenrohrs, dessen Innenraum von einem elektrischen Leiters durchsetzt wird, der im Innenraum des Außenrohres von einem Isolierstoff umgeben ist, in Form eines verdichteten Stangenmaterials. Ein derart aufgebautes „verdichtetes Stangenmaterial“ besteht aus im Vergleich zur Länge einer elektrischen Durchführung langen Abschnitten von Außenrohr, Isolierstoff, insbesondere in Form eines Isolierstoffrohrs und elektrischem Leiter, welche auf die vorstehend beschriebene Weise relativ zueinander angeordnet und verdichtet sind. Eine solche Verdichtung kann einerseits dadurch erfolgen, dass die einzelnen Komponenten miteinander verpresst sind, andererseits kann ein solcher Verdichtungseffekt aber auch z.B. durch Walzen, Hämmern oder Ziehen aus einem größeren Querschnitt erreicht werden.
• b) Entfernen des Außenrohrs an Abschnitten des Stangenmaterials, die voneinander um eine Länge, die der gewünschten Länge des Außenrohrs der herzustellenden Durchführung entspricht, beabstandet sind, wobei die Länge der Abschnitte, auf denen das Außenrohr entfernt wird, dem jeweils gewünschten Überstand des elektrischen Leiters relativ zur Stirnfläche entspricht,
• c) Entfernen des Isolierstoffs an Abschnitten des Stangenmaterials, die voneinander um eine Länge, die der gewünschten Länge des Außenrohrs der herzustellenden Durchführung entspricht, beabstandet sind, wobei die Länge der Abschnitte, auf denen der Isolierstoff entfernt wird, dem jeweils gewünschten Überstand des elektrischen Leiters relativ zur Stirnfläche entspricht, und
• d) Abtrennen eines Abschnitts des Stangenmaterials, dessen Länge der gewünschten Länge des elektrischen Leiters der herzustellenden Durchführung entspricht.

The inventive method for producing an electrical feedthrough with an outer tube, and an inner conductor of the outer tube passing electrical conductor whose ends project beyond the outer tube at least one of the end faces of the outer tube, wherein the electrical conductor is surrounded in the interior of the outer tube of an insulating material and wherein the entire assembly of outer tube, electrical conductor and insulating material is compressed has the following steps:

• a) providing an outer tube whose interior is penetrated by an electrical conductor which is surrounded in the interior of the outer tube of an insulating material, in the form of a compacted rod material. Such a constructed "compacted bar material" consists of compared to the length of an electrical feedthrough long sections of outer tube, insulating material, in particular in the form of an insulating tube and electrical conductor, which are arranged and compacted in the manner described above relative to each other. On the one hand, such compaction can take place in that the individual components are pressed together, but on the other hand such a compacting effect can also be achieved, for example, by rolling, hammering or drawing from a larger cross section.
• b) removing the outer tube at portions of the rod material which are spaced from one another by a length corresponding to the desired length of the outer tube of the bushing to be made, the length of the portions on which the outer tube is removed, the respective desired projection of the electrical conductor corresponds to the face,
• c) removing the insulating material at portions of the rod material which are spaced from each other by a length corresponding to the desired length of the outer tube of the bushing to be manufactured, the length of the portions on which the insulating material is removed, the respective desired projection of the electrical conductor corresponds to the end face, and
• d) separating a portion of the rod material whose length corresponds to the desired length of the electrical conductor of the implementation to be produced.

It is essential that the steps of the method with the exception of step a), which is always performed first, can be performed in different sequences. For example, it is possible first to separate a section from the bar stock provided in step a) according to step d) and then to process it according to steps b) and c). However, step d) may also be the last step, and by severing the last layer of bar stock remaining after complete completion of steps b) and c), i. of the electrical conductor.

It is also possible to carry out step c) before step b), e.g. by bringing a tool into contact with the insulating material from the end face of the rod material and scraping it out of the space between the outer tube and the electrical conductor.

It is also not absolutely necessary that the processing steps according to b) and c) are in each case completely processed before proceeding to the next step. It is therefore not necessary to first completely remove the outer tube on a desired section and then completely remove the insulating material on the desired section. Rather, it is possible and at least if the respective removal of outer tube and insulating material with the same tool and / or by machining under similar conditions such. Speed, contact pressure to the material or similar is feasible, also expedient, first on a the width of a tool used corresponding portion of the desired portion first remove the outer tube and the insulating material and possibly even the electrical conductor, for example. form by machining and to repeat these steps on the next section until the steps b) and c) are completed.

Still further, it is also possible that steps b) and c) are performed simultaneously, i. that outer tube and insulating material are simultaneously removed by the tool of the lathe in one go.

Already at this point, it is explicitly pointed out that in the following, when a "further processing step" is mentioned, it can be carried out in whole or in part at different times in the course of the process and in particular in the above described manner can be performed in several sections.

An essential part of the advantages of the method according to the invention results from the transition to no longer assemble the electrical feedthrough, as hitherto, modularly, but instead quasi "from the solid" or more precisely formulated from a compressed composite of outer tube provided as a rod material , whose interior is penetrated by an electrical conductor, which is surrounded in the interior of the outer tube of an insulating material is worked out. By "bar stock" is meant that the material is provided in a length that far exceeds the length of the electrical feedthroughs to be made so that a plurality of electrical feedthroughs can be made from a bar of material. On the one hand, compaction can take place in that the individual components are pressed together, but on the other hand, it can also be compressed, for example. be effected by rolling, hammering or drawing from a larger cross-section.

It has been shown that this approach has several advantages:
Firstly, in the compression of the bar material, its end portions, which lead to an uneven and in particular lower compression, scarcely have any effect. This means that the electrical feedthroughs made therefrom - especially when the end portions of the bar stock are optionally separated using a new bar - are more evenly, more evenly more densely compressed over their length than before, and more problematic with breakout Insulating material at the ends are effectively avoided.

This leads to an improvement in the resistance of the electrical feedthrough thus produced to mechanical stress, in particular in the form of tension, torsion or vibration, even when working nominally during pressing at the same pressure as in previously known production processes.

However, this effect is further enhanced by the fact that hitherto the pressure which can be used for pressing was limited by the fact that an elongation of the material during pressing had to be avoided so that the dimensions of the leadthrough and of the electrical conductor were within the required tolerances. However, since in the process according to the invention the molds subjected to these tolerances are not machined out of the material until they have been pressed, in the new process it is also possible to work with a significantly higher pressure.

However, the method according to the invention also brings with it a further significant advantage. In fact, if relatively soft materials are used for the electrical conductor of the feedthrough, the machining of these conductors is to provide suitable terminal contours, e.g. a connection thread, relatively difficult to perform because the materials can deform during machining. Therefore, turning or milling with very soft material can not be done very efficiently, since only a little can be delivered with a train and must be driven at a slow feed rate. This problem is the stronger, the longer the electrical conductors required for the implementation are.

Since, according to the invention, the shaping of the connection sections of the electrical conductor takes place only in the compressed state, the embedding in insulating material and outer tube achieved in this way increases the rigidity and strength of the object to be machined, which facilitates the machining.

Further manufacturing advantages are that a high degree of automation of the process is given, the electrical feedthroughs can be made freely falling on a lathes. In addition, electrical feedthroughs of the most varied length and with completely different contours of the electrical conductors can be manufactured from the same bar material, which leads to advantages in terms of storage.

Surprisingly, it also shows that these at first glance seem less less efficient in terms of material consumption - after all, not inconsiderable proportions of the insulating material and the outer tube used are ultimately only provided to be machined again - these material losses due to the much lower proportion of Committee parts that do not meet the specifications, can partially compile, completely compensate or even overcompensate, depending on the individual case.

In a particularly preferred embodiment of the method, in a further processing step, the ends of the electrical conductor which project beyond the end surfaces of the outer tube are brought into a desired shape. This may in particular be wholly or partly by machining, e.g. done by turning or milling.

A further advantageous development of the method is that in a further processing step, the surface of the outer tube of the implementation is modified. This can be done without high overhead and electrical feedthroughs are made, which meet very small outside diameter tolerances easily and / or their surface quality is optimized.

The invention will be explained in more detail with reference to drawings. Show it:

1a a first stage of the production of an electrical feedthrough according to the prior art,

1b a second stage of the production of an electrical feedthrough according to the prior art as a cross-sectional view along the direction of extension of the electrical feedthrough,

1c : a detail enlargement from the representation according to 1b .

1d a third stage of the manufacture of an electrical feedthrough according to the prior art,

1e : the implementation made by the method according to the prior art implementation as a cross-sectional view along the direction of extension of the electrical feedthrough, and

1f : a detail enlargement from the representation according to 1e ,

2a a first stage of the production of an electrical feedthrough according to the method according to the invention,

2 B a second stage of the production of an electrical feedthrough according to the method according to the invention,

2c a third stage of the production of an electrical feedthrough according to the method according to the invention,

2d a fourth stage of the production of an electrical feedthrough according to the method according to the invention,

2e a fifth stage of making an electrical feedthrough according to the method of the invention.

3a a first embodiment of an electrical feedthrough producible by the method according to the invention,

3b a second embodiment of an electrical feedthrough producible by the method according to the invention,

3c A third embodiment of an electrical feedthrough producible by the method according to the invention, and

3d : A fourth embodiment of an achievable with the inventive method electrical feedthrough in a partially opened representation.

For identical components of the same embodiments, the same reference number is used in different figures, unless stated otherwise.

First, based on the 1a to 1f in short, the known from the prior art manufacturing method for an electrical feedthrough 100 be explained. As in 1a shown, become an electrical conductor 110 , For example, in the form of a connecting bolt of the desired length L with machined into it by connecting sections 111 and 112 , a tube of insulating material 120 and an outer tube 130 provided.

Subsequently, the tube is made of insulating material 120 over the electrical conductor 110 pushed and on this arrangement the outer tube 130 positioned so that the in 1b shown arrangement arises in which between the individual components, as particularly well in the enlarged detail according to 1c it is still possible to see gaps between them 141 . 142 available. When sliding a precise positioning is important because the distances d1 and d2, which are the length that the electrical conductor on the respective sides of the electrical feedthrough 100 over the faces of the insulating material 121 . 122 or the end faces of the outer tube 131 . 132 survives, define, in many applications may have only small tolerances.

As in 1d is shown schematically, the structure is next assembled by radial compression, so that electrical conductor 110 , Tube of insulating material 120 and outer tube 130 be squeezed together and the in 1e shown electrical implementation 100 arises, at which the electrical implementation 100 passing electrical conductors 110 in the interior of the outer tube 130 with insulating material 120 is surrounded. Here are in 1e the occurring problems exaggerated: By pressing it comes to a poorly controllable and poorly reproducible elongation of the electrical conductor 110 , so that it now has a length L ', whereby also distances d1', d2 'are present instead of the required distances d1, d2. It also happens, as in 1f It can be seen particularly clearly, to a breaking out of the insulating material 120 at its end faces 121 . 122 ,

The sequence of 2a to 2e illustrates by way of example the procedure according to the invention for producing an electrical feedthrough 200 , 2a shows the inserted bar material 290 with outer tube 230 , inside the outer tube 230 arranged electrical conductor 210 and the surrounding of the electrical conductor tube of insulating material 220 in particular, here the entire remaining volume of the interior, not the electrical conductor 210 is occupied fills. These are electrical conductors 210 , Tube of insulating material 220 and outer tube 230 compressed under high pressure, so that a highly resistant to train, torsion and vibration arrangement results.

From the bar material 290 is used in the subsequent manufacturing steps with the tool 295 a lathe, not shown, by machining the electrical feedthrough 200 generated. 2 B shows how with the tool 295 on a section of bar stock 290 the outer tube 230 was removed, which in the example shown in a train along with the removal of the insulating material 220 at this point and part of the shape of the electrical conductor 210 in its end section 211 is done. The steps b) and c) are thus simultaneously and also together with part of the shaping of the end face 231 of the outer tube 230 protruding ends of the interior of the outer tube 230 penetrating electrical conductor 210 into a desired shape.

As in 2c shown can now be optional with another tool 296 a thread to be rolled up.

In 2d is a semi-finished implementation 200 shown with a pick 297 from the bar material 290 was tapped. Below then, as in 2e is shown, the still unprocessed side of the electrical feedthrough 200 with the tool 295 worked out of the whole, leaving the second end 212 of the electrical conductor 210 the electrical implementation 200 uncovered and brought by machining into the desired geometric shape, what again in a train for outer tube 230 , Insulating material 220 and electrical conductor 210 can happen.

Of course, when using a corresponding Drehmaschnine also the processing of the second end 212 be carried out without prior parting. Then by cutting the electrical conductor 210 at the desired distance from the right end face 232 of the outer tube 230 the electrical implementation 200 from the bar material 290 separated.

It should be emphasized at this point once again that the "stratified" ablation of the entire each abzuszubagenden sections of outer tube 230 , Insulating material 220 and individual areas of the electrical conductor 210 as it is based on the figure sequence 2a to 2e illustrated is by no means mandatory. The invention can be realized as well by bringing the tool to a given location and then sequentially modifying all the layers at this point before moving the tool a bit further and then making any necessary modifications at that location. In particular, the removal of multiple layers up to a processing of the electrical conductor in practice can be done in one go, if the tool of the lathe can be delivered so far that all these layers are removed simultaneously.

It is only essential that the implementation of the rod material is worked out instead of, as hitherto, composed of individual components and compacted.

Based on 3a to 3d should be clarified, how high the flexibility of the manufacturing method according to the invention with very low demands on the storage. These figures show electrical feedthroughs 310 . 320 . 330 . 340 , each consisting of an electrical conductor 311 . 321 . 331 . 341 one in the open section only 3d recognizable, the electrical conductor 311 . 321 . 331 . 341 surrounding insulating material 342 and an outer tube 313 . 323 . 333 . 343 are composed. In the production mold according to the prior art would have because of the different geometry of the electrical conductors 311 . 321 . 331 . 341 and different length of the area with surrounding insulating material 342 outer tube 313 . 323 . 333 . 343 are assembled, 12 different components are kept in stock. In contrast, according to the invention, only the bar stock has to be stored, from which all these and even more different electrical feedthroughs can be produced in a quick and simple manner.

LIST OF REFERENCE NUMBERS

100, 200, 310, 320, 330, 340

electrical implementation

110, 210, 311, 321, 331, 341

electrical conductor

120, 220, 342

insulator

121, 122

End faces of the insulating material

130, 230, 313, 323, 333, 343

outer tube

131, 132, 231, 232, 314, 315, 324, 325, 334, 335, 344, 345

End faces of the outer tube

141, 142

gap

211, 212

Ends of the electrical conductor

290

bar material

295

Tool

L, L '

Length of the electrical conductor

l

 Length of outer tube

d, d '

distance

Claims (4)

Method for producing an electrical feedthrough ( 200 . 310 . 320 . 330 . 340 ) with an outer tube ( 230 . 313 . 323 . 333 . 343 ), which has an interior, and with a the interior of the outer tube ( 230 . 313 . 323 . 333 . 343 ) passing through electrical conductors ( 210 . 311 . 321 . 421 ), whose ends on at least one of the end faces ( 231 . 232 . 314 . 315 . 324 . 325 . 334 . 335 . 344 . 345 ) of the outer tube ( 230 . 313 . 323 . 333 . 343 ) the outer tube ( 230 . 313 . 323 . 333 . 343 protrude), wherein the electrical conductor ( 210 . 311 . 321 . 421 ) in the interior of the outer tube ( 230 . 313 . 323 . 333 . 343 ) of an insulating material ( 120 . 220 . 342 ) is surrounded and wherein the entire arrangement of outer tube ( 230 . 313 . 323 . 333 . 343 ), electrical conductor ( 210 . 311 . 321 . 421 ) and insulating material ( 220 . 342 ) is compressed with the steps a) providing an outer tube ( 230 . 313 . 323 . 333 . 343 ) with an interior space occupied by an electrical conductor ( 210 . 311 . 321 . 421 ) is penetrated in the interior of the outer tube ( 230 . 313 . 323 . 333 . 343 ) of an insulating material ( 120 . 220 . 342 ), in the form of a compacted rod material ( 290 ), b) removing the outer tube ( 230 . 313 . 323 . 333 . 343 ) at portions of the rod material which are spaced from each other by a length corresponding to the desired length of the outer tube ( 230 . 313 . 323 . 333 . 343 ) of the implementation ( 200 . 310 . 320 . 330 . 340 ), wherein the length of the sections on which the outer tube ( 230 . 313 . 323 . 333 . 343 ) is removed, the respectively desired supernatant of the electrical conductor ( 210 . 311 . 321 . 421 ) relative to the end face ( 231 . 232 . 314 . 315 . 324 . 325 . 334 . 335 . 344 . 345 ), c) removing the insulating material ( 220 . 342 ) Sections of bar stock ( 290 ) spaced from each other by a length corresponding to the desired length of the outer tube ( 230 . 313 . 323 . 333 . 343 ) of the implementation ( 200 . 310 . 320 . 330 . 340 ), wherein the length of the sections on which the insulating material ( 220 . 342 ), the respectively desired supernatant (d1, d2) of the electrical conductor ( 210 . 311 . 321 . 421 ) relative to the end face ( 231 . 232 . 314 . 315 . 324 . 325 . 334 . 335 . 344 . 345 ), and d) severing a portion of the rod material ( 290 ), the length of the desired length (L) of the electrical conductor ( 210 . 311 . 321 . 421 ) of the implementation ( 200 . 310 . 320 . 330 . 340 ) corresponds. A method according to claim 1, characterized in that in a further processing step, the end faces ( 231 . 232 . 314 . 315 . 324 . 325 . 334 . 335 . 344 . 345 ) of the outer tube ( 230 . 313 . 323 . 333 . 343 ) protruding ends of the interior of the outer tube ( 230 . 313 . 323 . 333 . 343 ) passing through electrical conductor ( 210 . 311 . 321 . 421 ) are brought into a desired shape. A method according to claim 1 or 2, characterized in that the further processing step, with which the end faces ( 231 . 232 . 314 . 315 . 324 . 325 . 334 . 335 . 344 . 345 ) of the outer tube ( 230 . 313 . 323 . 333 . 343 ) protruding ends of the interior of the outer tube ( 230 . 313 . 323 . 333 . 343 ) passing through electrical conductor ( 210 . 311 . 321 . 421 ) are brought into the desired shape, a machining, in particular turning or milling is or includes. Method according to one of the preceding claims, characterized in that in a further processing step , the surface of the outer tube ( 230 . 313 . 323 . 333 . 343 ) is modified.

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