EP3422480A1 - Contact system for contacting a braided shield and a contact element - Google Patents

Abstract

The invention relates to a contact system for contacting an aluminum screen braid (7) comprising a contact element (1) - An electrically conductive cable (4); - The aluminum wire mesh (7) comprising a plurality of aluminum wires, which is at least partially arranged extending between a primary insulation (6) and a secondary insulation (8) of the electrically conductive cable (4); - The contact element (1) which can be slid onto the electrically conductive cable (4) and has an outer sleeve (3) and an inner sleeve (2) which can be pushed into the latter wherein the inner sleeve (2) has a first contact surface (2a) and the outer sleeve (3) has a second contact surface (3a), wherein each contact surface (2a, 3a) each have areas with different sized cross section and the contact surfaces (2a, 3a) are formed such that the aluminum braided shield (7) is clamped in a contact position by axial telescoping of inner sleeve (2) and outer sleeve (3) and contacted with the contact part (1). In order to easily increase the clamping force in defined areas of the contact surfaces (2a, 3a) by design measures, the first (2a) and the second contact surface (3a) are conical, wherein the opening angle of the cones are at least partially different sizes ,

Description

FIELD OF THE INVENTION

The invention relates to a contact system for contacting an aluminum braided shield comprising a contact element
an electrically conductive cable having an inner electrical conductor, a primary insulation surrounding the inner electrical conductor and a secondary insulation surrounding the primary insulation;
the aluminum screen braid comprising a plurality of aluminum wires, which is disposed running at least in sections between the primary insulation and the secondary insulation of the electrically conductive cable;
the push-on to the electrically conductive cable contact element which comprises an outer sleeve and an at least partially insertable into the outer sleeve inner sleeve.

STATE OF THE ART

Electrical cables whose inner conductors carry high voltages require electrical shielding to prevent interference with nearby electrical or electronic components. Similarly, the shield can also be provided to protect the inner conductor against external electrical and / or magnetic interference. For the purpose of shielding a braided shield, which consists of a plurality of strands of an electrically conductive material, is provided which surrounds the electrical inner conductor. The braided screen is usually located within a cable sheath and is between a primary insulation, also called inner sheath, which is arranged between the inner conductor and braided shield, and a secondary insulation, also called outer sheath or cable sheath, which surrounds the braided shield outside arranged. In order to increase the shielding effect of the shielding braid can additionally be provided either between the primary insulation and the braided shield or between the braided shield and the secondary insulation, a shielding film, which is usually a plastic-laminated aluminum foil. This screen foil transmits no appreciable currents and is not mitkontaktiert in the case of contacting the screen braid, but separated when exposing the shield braid.

In order to ensure the shielding of the inner conductor or the equipotential bonding of the shielding braid, it is necessary for the shielding braid in the end regions of the electrical cable to be connectable to a ground. For this purpose, at least one contact element is usually provided at each end of the cable, which are electrically conductively connected to the braided shield and can be connected to the ground.

Known method for connecting a screen braid made of copper with a contact element, for example in the DE 10 2015 004 485 B4 are usually realized in that a support sleeve is pushed onto the secondary insulation of the cable and the exposed braid is knocked back over the support sleeve. The contact part is then guided over the support sleeve and the screen braid resting thereon and radially pressed for contacting with a suitable tool, for example, crimped. By the pressing process, the braid between support sleeve and contact part is clamped. These methods can only be used for materials with good transverse conductivity, because the compression of the shield braid is only selective.

As a conductive material for braided shields are also aluminum or aluminum alloys, which is used due to its low mass in many applications, such as the automotive sector, especially in electrically powered cars. However, if aluminum wires or an aluminum alloy are pressed together, these wires naturally already have only one very hard to penetrate oxide layer on its surface. Due to the radial compression, a contacting process for a braided screen which is customary in copper technology is unable to produce contact with all the aluminum wires of the aluminum braided shield with the contact element, since the oxide layers forming on the aluminum wires prevent the transverse conductivity in the pressed areas. Thus, by known methods, the oxide layers can not be broken for all wires in the braided shield. It has also been found that with known contacting methods in aluminum braided shields no stable connection can be achieved over a thermal cycling load.

In order to enable the uniform shielding contact with these materials, known connection methods for aluminum screen braids make use of additional measures in order to ensure the contacting of all aluminum wires and, if appropriate, to be able to break up the oxide layer. For example, is from the DE 10 2012 00 137 B4 It is known that when connecting an aluminum screen braid to a sleeve, the braided screen is knocked back over the sleeve and the connection is made by means of ultrasonic welding. In this process, a cohesive connection between the braided shield and the contact part is made by supplying heat.

On the one hand, this type of connection technique has the disadvantage that the quality of the connection always influences the quality of the connection; in this case, above all adhering substances from the preceding processes are interference quantities. On the other hand, the production of such electrically conductive connections between an aluminum braided screen and a contact element is dependent on the presence of expensive welding systems, which are still not portable and therefore not flexible.

The EP 2 874 236 A1 describes a contact system consisting of a first inner contact part and a second outer one Contact part by means of which an aluminum wire screen comprising a plurality of individual wires can be clamped and contacted. In this case, the wire screen is pressed between a conical outer surface of a contact region of the first contact element and a conical inner surface of the second contact element via clamping means of the contact system.

OBJECT OF THE INVENTION

It is therefore an object of the invention to overcome the known contact systems of the prior art and to propose a system which enables reliable contacting of an aluminum screen mesh with a contact element in a simple manner, wherein the clamping force in defined areas of the contact surfaces by constructive measures should be increased.

PRESENTATION OF THE INVENTION

This object relates to an inventive contact system for contacting an aluminum screen mesh with a contact element of the type mentioned, wherein the inner sleeve having a first contact surface and the outer sleeve has a second contact surface for contacting the aluminum screen mesh, wherein the first and / or second contact surface respectively having different sized cross-section with respect to a conductor axis of the electrically conductive cable,
and wherein the contact surfaces are formed such that the aluminum wires of the aluminum screen mesh are clamped in a contact position of the contact part by axially telescoping inner sleeve and outer sleeve between the contact surfaces and contacted with the contact part.

As electrical inner conductor of electrically conductive material, preferably copper, aluminum or at least one of these metals-containing alloys are understood in the context of the invention both individual conductors as well as several Single conductors existing strands or a package of two, three, four or more strands, which are covered by the primary insulation. The electrical inner conductor defines a conductor axis, which follows the course of the electrical cable, so in sections may be straight, curved or angled. However, at least in the area of the contacting, the conductor axis generally runs in a straight line.

Under sleeve is usually understood an element which comprises a, preferably centric, through-opening and a through-opening having, preferably rotationally symmetrical, shell body. The passage opening can basically have any geometric cross-section, as long as the passage of at least a portion of the electrically conductive cable is ensured. The inner sleeve is that sleeve, which is arranged in the contact position in the radial direction closer to the inner conductor. In other words, the inner sleeve is pushed onto the electrically conductive cable, so that the passage opening of the inner sleeve, hereinafter called cable feedthrough, is advantageously adapted to the geometry of the electrical inner conductor of the cable, for example circular, elliptical or substantially polygonal. The sheath body of the inner sleeve is formed such that the inner sleeve is at least partially inserted into the outer sleeve, wherein the first contact surface of the inner sleeve is usually formed by a radially outer peripheral surface of the inner sleeve. In general, the insertability is achieved in that the outer dimensions of the inner sleeve is smaller than or equal to the inner dimensions of the passage opening of the outer sleeve. The second contact surface of the outer sleeve is generally formed by a radially inner peripheral surface, that is, by the boundary surface of the through hole of the outer sleeve.

In any case, the contact surfaces are defined by a surface of the inner sleeve or the outer sleeve and theoretically include a volume. If in the light of the invention of A cross-section of a contact surface is referred to, mutatis mutandis, the cross-section of the enclosed volume understood, which is aligned normal to the conductor axis.

In the contact position, the aluminum braided shield is disposed between the contact surfaces so that the aluminum wires of the aluminum braid, preferably all aluminum wires, contact both the first contact surface and the second contact surface. By virtue of the differently sized cross sections provided according to the invention, at least one of the contact surfaces of the inner sleeve and the outer sleeve, which are usually arranged correspondingly in the contact position, the aluminum wires of the aluminum screen mesh contacting the contact surfaces are already clamped by axial telescoping of outer sleeve and inner sleeve. Due to the different cross-sections, with circular cross-section corresponding to the diameter, in different areas of at least one of the interacting contact surfaces, which areas either continuously or abruptly merge into each other, at least one area is defined, in which when telescoping the sleeves of the contact surfaces on the one aluminum Screen mesh acting clamping force is applied. Each of the contact surfaces preferably has regions with different sized cross-sections.

Thus, either an electrical contact between the outer sleeve and / or the inner sleeve and the aluminum wires is made to allow potential equalization. For the choice of the geometry of the cooperating contact surfaces of the sleeves is a variety of shapes in question, as long as the design of the contact surfaces and their cross sections at least one area is defined, through which a telescoping of the sleeves acting on the aluminum shielding clamping force is exerted.

Under axial telescoping or compressing is understood in the context of the invention that the two sleeves are pushed into each other in the direction of a conductor axis or pressed and not the compression, as known from the prior art, by subsequent radial pressing, for example. Crimping achieved becomes. Thus, a uniform contact between the aluminum wires and the contact element is already achieved by nesting the sleeves, since the compression is no longer radially or selectively, but evenly over the contact surface and the aluminum wires running.

Although the invention relates to an aluminum screen braid made of aluminum wires, it should be expressly understood that the contact element according to the invention is also suitable for braided shields of other materials or alloys, for example of copper or copper alloys.

In a particularly simple manner, a clamping and / or a compression / shearing of the aluminum wires of the aluminum screen mesh between the contact surfaces in accordance with the invention can be achieved in that the first and the second contact surface are conical. Due to the conicity, which generally refers to the conductor axis, the two contact surfaces, it is achieved that the contact surfaces exert a clamping force on the aluminum wires by an axial displacement of the sleeves in the contact position or a pressure spike for crushing / shearing (ie cold welding ) of the aluminum wires form. It goes without saying that the contact surfaces are formed corresponding to each other, at least when both contact surfaces are conical.

An increase in the clamping force or a particularly efficient definition of a region in which a cold welding is generated, according to the invention further achieved in that the first and the second contact surface are conical, wherein the opening angle of the cones at least sections are different in size. Due to the different opening angle relative to the conductor axis, the axial telescoping on the one hand leads to an increase in the clamping force in that region in which the clear distance between the contact surfaces is minimal. On the other hand, this can define an area between the contact surfaces, in which a pressure peak forms during the compression of the sleeves. Because of this pressure spike, shear / crushing of the aluminum wires to form the cold weld can be achieved.

In order to ensure the contact between the aluminum wires of the aluminum screen braid and the contact element in a simple manner, in particular in order to penetrate the oxide layer of the aluminum wires safely, is provided in an embodiment of the invention that the contact surfaces are further formed such that in the Contact position of the contact element by axially compressing the outer sleeve and inner sleeve, a crushing / shearing of the aluminum wires of the aluminum shield braid and cold welding of the aluminum wires of the aluminum shield braid takes place with the contact element.

The contacting between aluminum braid and contact element is thus achieved in the embodiment that the contact surfaces of the inner sleeve and outer sleeve are designed such that the oxide layer having surface of all aluminum wires of the aluminum screen braid when axially compressing the inner sleeve and outer sleeve is broken, so that a cold welding between at least one contact surface and the aluminum braid can arise. To break the surface, the aluminum wires are squeezed during compression or at least partially sheared / sheared, so that it comes to a cold welding between the aluminum wires and at least one of the sleeves, so the inner sleeve and / or the outer sleeve. By, preferably corresponding to each other Regions of different cross-section of the contact surfaces, in turn, at least one area is defined in which forms a pressure peak during compression. This area usually corresponds to the area in which the clamping force is exerted. A cold-welded state can thus be achieved if the sleeves are pressed axially together, for example, starting from the contact position in which the aluminum braided shield is clamped between the contact surfaces.

Cold welding utilizes the effect of aluminum tending to flow using very high pressure and thereby cold welding to contacting materials. Such a compound is insoluble and electrically conductive.

In other words, by choosing the geometry of the cooperating contact surfaces, taking into account the regions of different sized cross sections, it is ensured that the oxide layer is reliably broken during the axial compression of the sleeves by squeezing the aluminum wires of the aluminum screen mesh in an area defined by the contact surfaces (sheared off). At the same time, the connection by means of the contact system according to the invention due to the local shear / pinch and taking place there cold-welding is insensitive to superficial contamination of the aluminum shield braid. For the choice of the geometry of the cooperating contact surfaces of the sleeves is a variety of shapes in question, as long as the design of the contact surfaces and their areas with different cross-section at least one area is defined in which forms a pressure peak during axial compression, which is used for crushing / Shearing the aluminum wires and ultimately leads to cold welding.

In general, one of the sleeves is made of copper or a, preferably coated, copper alloy and serves as a contact sleeve while the other sleeve acts as a support sleeve. Advantageously, the cold welding takes place both between the contact sleeve and between the support sleeve and the aluminum braided screen.

In a further embodiment variant of the invention, it is provided that the second contact surface of the outer sleeve limits an insertion volume for the inner sleeve and the first contact surface of the inner sleeve is formed by a portion of the inner sleeve which can be introduced into the insertion volume. The insertion volume of the outer sleeve is usually formed by a portion of the passage opening, preferably completely through the passage opening. Due to the design of insertion volume of the outer sleeve and insertable portion of the inner sleeve, the interaction of the contact surfaces can be achieved in a simple manner.

According to a further embodiment variant of the invention, it is provided that introduction volume and / or insertable section taper at least in sections relative to the conductor axis. By the taper of at least one, preferably both, the contact surfaces forming element (s) a geometry of the contact surfaces is achieved in a simple manner, which causes a pinch or shearing / shearing of the aluminum screen mesh in the contact position. In the tapered portion of that region forms, which exerts a clamping force on the aluminum wires or causes a crushing / shearing of the aluminum wires. It goes without saying that two, three, four or more tapered sections can be provided. In other words, the contact surfaces may be formed such that in an intermediate position of the contact part, in which the inner sleeve is partially inserted into the outer sleeve, forms a gap for receiving the aluminum screen mesh between the contact surfaces and the gap has at least one cross-sectional constriction.

A particularly space-saving design of the contact element is achieved in a preferred embodiment in that the inner sleeve is completely received in the contact position in the insertion volume of the outer sleeve. In other words, the entire inner sleeve is formed as an insertable section.

In order to be able to produce and define the areas with different sized cross sections in the contact surfaces in a simple manner, it is provided in a further embodiment of the invention that the first and / or the second contact surface in the contact position are at least partially oblique to the conductor axis running , In other words, the imaginary extensions of the first and / or second contact surfaces intersect the conductor axis.

The effects mentioned above in connection with the conical contact surfaces can be further improved in that the first and / or the second contact surface has at least one kink. Knick is understood here as meaning the change in the slope in the conical or frustoconical contact surface or, in other words, the continuous transition between two sections merging into one another with different opening angles of the contact surface. Each kink defines a peripheral contact edge on which a pressure peak forms and / or which exerts a clamping force on the aluminum screen mesh. Advantageous effects are already observed if only one of the contact surfaces has a kink. However, variants are also conceivable in which a contact surface has several kinks or both contact surfaces have one or more kinks. The kinks in turn define the area in which in the contact position, the clamping force is exerted on the aluminum wires or forms in the contact position, the pressure peak.

As a further possibility to a clamping and / or crushing / shearing of the aluminum wires of the aluminum shield braid between the contact surfaces of the sleeves, is provided in a particularly preferred embodiment of the invention that the first and / or the second contact surface has at least one stage. In this case, a step is understood as meaning a sudden enlargement or reduction of the cross-sectional area defining the corresponding contact surface normal to the conductor axis. Such a configuration can be combined with any geometric shape of the contact surfaces, for example, the first and / or second contact surface may have a cylindrical shape or the previously described conical shape. It is advantageous if both contact surfaces have mutually corresponding first and second stages. The at least one first and / or second stage in turn defines the region in which the pressure peak is formed in the contact position for exerting the clamping force or for pinching / shearing and cold welding the aluminum wires of the aluminum screen mesh. Advantageous effects are already observed when only one of the contact surfaces has a step. However, variants are also conceivable in which a contact surface has several stages or both contact surfaces have one or more stages.

In order to enhance the advantages mentioned above in connection with the steps, according to a further particularly preferred embodiment of the invention, the first contact surface has at least a first step and the second contact surface has at least one second step, the steps each forming a peripheral contact edge and contacting the aluminum braid in the contact position with the contact edges. The contact edges in turn defines that region in which, in the contact position, the pressure peak for exerting the clamping force or for pinching / shearing and cold welding of the aluminum wires of the aluminum screen mesh is formed.

It is advantageous for potential equalization if one of the sleeves is designed as a contact sleeve, via which the potential equalization is made possible and the other sleeve is designed as a support sleeve. In order to achieve good connection properties between the aluminum wires of the aluminum screen braid and the contact sleeve, it is particularly advantageous if the contact sleeve is made of copper or a copper alloy. Depending on the application, either the inner sleeve or the outer sleeve may be formed as a contact sleeve. It is also conceivable that both contact sleeve and support sleeve made of copper or a copper alloy are made. Therefore, it is provided in further embodiments of the invention that the inner sleeve and / or the outer sleeve is made of copper or a copper alloy.

Particularly good clamping properties or cold welding properties and electrical line properties are achieved in a further embodiment in that one of the sleeves is made of copper or a copper alloy and the other sleeve is made of aluminum or an aluminum alloy. By the made of aluminum or an aluminum alloy sleeve, so designed as a support sleeve sleeve, the corrosion tendency of the aluminum wires in the region of the contact element is further minimized. In order to achieve a particularly high strength of the support sleeve, it can also be made of stainless steel, which is preferably protected against corrosion, for example by means of a corrosion-inhibiting coating.

In order to improve the corrosion properties of the sleeve made of copper or a copper alloy, preferably the contact sleeve, and to reduce the tendency of the aluminum wires to corrode, it is provided in another particularly preferred embodiment of the invention that the sleeve made of copper or a copper alloy has a corrosion-inhibiting coating having. For one Such corrosion-inhibiting coating are in particular nickel and / or tin or nickel and / or tin-containing alloys as coating materials.

In order to be able to contact the aluminum screen braid arranged between primary insulation and secondary insulation with the contact element, it is generally necessary to cut the cable and strip the aluminum screen braid at an open end of the cable, that is to remove at least the secondary insulation, and the inner sleeve relative to position the electrical conductor. Therefore, in a further embodiment of the invention, it is provided that the secondary insulation is removed at least in that region of the electrically conductive cable in which the contact element is arranged in the contact position, wherein the region having the smallest cross section of the first contact surface at the region having the secondary insulation of the cable adjoins.

While it is known in the art that the contact element is seated in the contact position on the secondary insulation of the cable and the braided screen is folded back over the contact element so as not to damage the inner conductor by the subsequent radial compression or welding, it is by the invention Design of inner sleeve and outer sleeve, however, possible, the contact element to save space in the stripped area of the cable, ie in that area in which the secondary insulation is removed to arrange. The reason for this is that the clamping or cold welding is achieved only by telescoping or axial compression of inner sleeve and outer sleeve and thus there is no risk that the inner conductor is injured by the axial compression of the sleeves. Preferably, the inner sleeve is inserted between the primary insulation and the aluminum braided shield, so that the inner sleeve, on the one hand, contacts the primary insulation and, on the other hand, the aluminum braided screen. Therefore, in a further preferred embodiment of the invention, it is provided that the inner sleeve is arranged in the contact position between the primary insulation and the aluminum braided screen, wherein preferably a cable feedthrough of the inner sleeve contacts the primary insulation. Thus, both inner sleeve and outer sleeve or at least their contact surfaces are in the radial direction in the stripped region of the cable.

In a further embodiment variant of the invention, it is provided that the aluminum braided screen is folded over the first contact surface of the inner sleeve and a cable bushing of the inner sleeve contacts the secondary insulation or the aluminum braided screen. If the inner sleeve is seated in the contact position on the secondary insulation and thus the cable bushing, that is to say the through-opening, of the inner sleeve contacts the secondary insulation, the aluminum braided screen must be turned over for contacting via the first contact surface. A particularly space-saving design is achieved in that the inner sleeve is pushed in the stripped area of the cable over the aluminum braided shield and then the aluminum braided shield is folded over the first contact surface. The cable gland contacts the section of the aluminum screen braid adjacent to the primary insulation and the first contact surface contacts the folded-back part of the aluminum screen braid.

• gegebenenfalls Entfernen eines Abschnitts einer das Aluminium-Schirmgeflecht umgebenden Sekundärisolation und/oder eines Abschnitts einer den Innenleiter umgebenden Primärisolation im Bereich eines offenen Endes des elektrischen Kabels;
• gegebenenfalls Aufschieben von Innenhülse und Außenhülse auf das elektrisch leitende Kabel;
• Platzieren der Innenhülse zwischen Aluminium-Schirmgeflecht und Innenleiter, wobei das Aluminium-Schirmgeflecht an der ersten Kontaktoberfläche anliegt;
• Verschieben der Außenhülse in Richtung der Innenhülse in eine Kontaktposition des Kontaktteils in dem die zweite Kontaktoberfläche der Außenhülse das Aluminium-Schirmgeflecht kontaktiert und die Aluminiumdrähte des Aluminium-Schirmgeflechts zwischen den Kontaktoberflächen festgeklemmt wird.

One possibility for using the contact system according to the invention relates to a method for contacting an aluminum screen braid formed from aluminum wires and surrounding an electrical inner conductor of an electrically conductive cable and a contact element, wherein the contact element comprises an inner sleeve with a first contact surface and an outer sleeve with a second contact surface, taking the following steps:

• optionally removing a portion of a surrounding the aluminum braid secondary insulation and / or a portion of the inner conductor surrounding Primary insulation in the region of an open end of the electric cable;
• optionally sliding inner sleeve and outer sleeve onto the electrically conductive cable;
• Placing the inner sleeve between the aluminum braid and the inner conductor with the aluminum braid abutting the first contact surface;
• Sliding the outer sleeve in the direction of the inner sleeve in a contact position of the contact part in which the second contact surface of the outer sleeve, the aluminum screen mesh contacted and the aluminum wires of the aluminum shield braid between the contact surfaces is clamped.

In this case, first the electrically conductive cable is cut to length and a resulting open end of the cable stripped, wherein the stripping at least the secondary insulation is removed in that or up to that area in which the contact with the contact element is to be produced. It goes without saying that even an already cut cable with stripped open end can be used.

Subsequently, inner sleeve and outer sleeve are pushed onto the cable, wherein the cable through the passage opening of the sleeves, respectively insertion volume and cable gland, is performed. However, it is also conceivable that the electrical cable is already delivered prefabricated, so that outer sleeve and inner sleeve only have to be pushed together or pressed together.

If the contact element is to be arranged in the contact position in the non-stripped region of the cable, it is necessary to first push the inner sleeve onto the secondary insulation, then turn over the aluminum braided screen via the secondary insulation or via the inner sleeve and subsequently the outer sleeve from the stripped region of the cable in the direction of the inner sleeve to push. In other words, the inner sleeve between the secondary insulation and the folded-back portion of the Aluminum screen braid placed. According to a further embodiment variant of the method, it is therefore provided that first the inner sleeve is pushed over the secondary insulation and subsequently the aluminum braided screen is folded over the first contact surface before the outer sleeve is displaced in the direction of the inner sleeve. In this case, the outer sleeve is moved from the direction of the open end of the cable in the direction of the secondary insulation having portion of the electrically conductive cable to be brought into the contact position.

However, if the contact element is to be arranged in the contact position in a space-saving manner in the stripped region of the cable, as is provided in a preferred embodiment of the method, the outer sleeve is first pushed onto the secondary insulation of the cable. The inner sleeve is subsequently inserted between the primary insulation and the aluminum braided shield so that it is no longer necessary to turn over the aluminum braided shield. Subsequently, the outer sleeve is then pushed in the direction of the stripped region of the cable or in the direction of the inner sleeve. According to a further embodiment of the method is therefore provided that first the outer sleeve is pushed over the secondary insulation and subsequently the inner sleeve between the aluminum braided shield and primary insulation is inserted before the outer sleeve is moved in the direction of the inner sleeve. At this time, the outer sleeve is shifted from the portion of the electric wire having the secondary insulation toward the open end of the cable to be brought into the contact position.

It is particularly space-saving when the inner sleeve is pushed in the stripped area directly onto the voltage applied to the primary insulation aluminum screen braid and the aluminum screen braid is folded in the stripped region of the electrically conductive cable on the first contact surface. The aluminum screen braid is exposed so far that a section on the deferred Inner sleeve protrudes and can be handled. Subsequently, the outer sleeve is then displaced in the direction of the secondary insulation having region of the electrically conductive cable. According to a further embodiment variant of the method, it is therefore provided that the inner sleeve is first pushed over the aluminum braided screen and subsequently a section of the aluminum braided shield projecting over the inner sleeve is folded over the first contact surface before the outer sleeve is displaced in the direction of the inner sleeve. In this case, the outer sleeve is moved from the direction of the open end of the cable in the direction of the secondary insulation having portion of the electrically conductive cable to be brought into the contact position.

In any case, in all of the above-mentioned variants, the inner sleeve is placed in the radial direction between the inner conductor and the braided shield, optionally with the interposition of the primary insulation and / or the secondary insulation.

Due to the axial telescoping of outer sleeve and inner sleeve, the aluminum wires of the aluminum screen mesh are clamped between the contact surfaces, as described in detail in connection with the contact system.

• Weiterverschieben und Pressen der Außenhülse in Richtung der Innenhülse sodass durch die Druckbeaufschlagung der Kontaktoberflächen eine Quetschung/Scherung der Aluminiumdrähte des Aluminium-Schirmgeflechts und Kaltverschweißung der Aluminiumdrähte des Aluminium-Schirmgeflechts an den Kontaktoberflächen des Kontaktelements stattfindet.

In order to ensure the contact between the aluminum wires of the aluminum screen mesh and the contact element in a simple manner, in particular in order to be able to penetrate the oxide layer of the aluminum wires safely, it is provided in a variant of the method that the following method step is also carried out:

• Continue pushing and pressing the outer sleeve in the direction of the inner sleeve so that the pressurization of the contact surfaces, a crushing / shearing of the aluminum wires of the aluminum screen braid and cold welding of the aluminum wires of the aluminum screen mesh takes place at the contact surfaces of the contact element.

It is particularly advantageous if a system according to the invention is used in combination with the described method or if a system according to the invention can be produced by the described method.

BRIEF DESCRIPTION OF THE FIGURES

The invention will now be explained in more detail with reference to exemplary embodiments. The drawings are exemplary and are intended to illustrate the inventive idea, but in no way restrict it or even reproduce it.

Fig. 1

eine Schnittansicht eines erfindungsgemäßen Kontaktsystems in einer Kontaktposition;

Fig. 2

eine axonometrische Ansicht des Kontaktsystems in der Kontaktposition;

Fig. 3

eine axonometrische Ansicht eines ersten Ausführungsbeispiels des Kontaktsystems in einer Zwischenposition;

Fig. 4

eine axonometrische Ansicht eines zweiten Ausführungsbeispiels des Kontaktsystems in einer Zwischenposition;

Fig. 5

eine vergrößerte Detailansicht eines Kontaktelements des ersten Ausführungsbeispiels;

Fig. 6

eine vergrößerte Detailansicht eines Kontaktelements eines zweiten Ausführungsbeispiels;

Fig. 7a,b,c,d

Schnittansichten des ersten Ausführungsbeispiels in mehreren aufeinanderfolgenden Positionen;

Fig. 8a,b,c,d

Schnittansichten des zweiten Ausführungsbeispiels in mehreren aufeinanderfolgenden Positionen;

Fig. 9

eine Schnittansicht eines dritten Ausführungsbeispiels des Kontaktsystems in der Kontaktposition;

Fig. 10

eine Schnittansicht eines vierten Ausführungsbeispiels des Kontaktsystems in der Kontaktposition;

Showing:

Fig. 1

a sectional view of a contact system according to the invention in a contact position;

Fig. 2

an axonometric view of the contact system in the contact position;

Fig. 3

an axonometric view of a first embodiment of the contact system in an intermediate position;

Fig. 4

an axonometric view of a second embodiment of the contact system in an intermediate position;

Fig. 5

an enlarged detail view of a contact element of the first embodiment;

Fig. 6

an enlarged detail view of a contact element of a second embodiment;

Fig. 7a, b, c, d

Sectional views of the first embodiment in several successive positions;

Fig. 8a, b, c, d

Sectional views of the second embodiment in several successive positions;

Fig. 9

a sectional view of a third embodiment of the contact system in the contact position;

Fig. 10

a sectional view of a fourth embodiment of the contact system in the contact position;

WAYS FOR CARRYING OUT THE INVENTION

The Figures 1 and 2 The aluminum screen braid 7 comprises a plurality of aluminum wires and extends between a primary insulation 6 and a secondary insulation 8 of an electrically conductive cable 4. The structure of the cable. 4 , which in particular in FIG. 2 and 4 is apparent, looks like this:
The core of the cable 4 is formed by an electrical inner conductor 5, which defines a rectilinear conductor axis 15 in the figures. In the present figures, the inner conductor 5 is formed by a plurality of individual conductors bundled as a strand and has a substantially circular cross-section. It goes without saying that the number of individual conductors of a strand and the number of strands or the geometry of the cross section for the invention itself are irrelevant. In principle, therefore, for example, both individual conductors as well as elliptical or polygonal cross sections of the inner conductor 5 are conceivable. On the inner conductor 5 is a primary insulation 6, also called inner sheath or conductor insulation, applied, which causes an insulation between the inner conductor 5 and the aluminum shield braid 7. On the aluminum braid 7 then a secondary insulation 8, also known as outer sheath or cable sheath, applied, which inner conductor 5 and aluminum shield braid 7 isolated from the environment.

Before the contacting of the aluminum screen mesh 7 and the contact element 1 can be realized, usually the electrically conductive cable 4 must be cut to length, so that an open end of the cable 4 is formed. In that region of the electrically conductive cable 4, in which the contact element 1 can be arranged in the contact position, the secondary insulation 8 is removed. In the following, therefore, in this context, the stripped area is spoken. In general, the stripped portion is disposed in the portion of the open end of the cable 4 and extends as in Figs As can be seen in the figures, furthermore, an end-side section of the cable 4 can be freed of primary insulation 6, aluminum screen braid 7 and secondary insulation 8, so that the inner conductor 5 can be used for electrical purposes Connection is free.

The contact element 1 comprises an inner sleeve 2 with a first contact surface 2a and an outer sleeve 3 with a second contact surface 3a, wherein the contact surfaces 2a, 3a are formed for the contacting of the aluminum screen mesh 7 in the illustrated contact position. The inner sleeve 2 is at least partially inserted into the outer sleeve 3. At least one of the two sleeves 2, 3 is designed as a contact sleeve and can be electrically connected to a ground for the purpose of equipotential bonding.

Since the contact surfaces 2a, 3a of the sleeves 2,3 are formed such that the aluminum wires of the aluminum screen mesh 7 in the contact position of the contact part 1 by axially nesting of inner sleeve 2 and outer sleeve 3 between the contact surfaces 2a, 3a clamped and with the contact part 1 are contacted, the aluminum braid 7 is clamped in the illustrated contact position between the contact surfaces 2a, 3a. Furthermore, the contact surfaces 2a, 3a in the embodiments are also formed such that in the contact position of the contact element 1 by axially compressing the outer sleeve 3 and inner sleeve 2, a pinch / shear of the aluminum wires of the aluminum screen braid 7 and cold welding of the aluminum wires of the aluminum screen braid. 7 takes place with the contact element 1. This configuration is achieved in that the contact surfaces 2a, 3a have regions of different cross-section, in the present case of different diameters. Therefore, the electrical connection between the aluminum wires of the aluminum screen mesh 7 and the contact element 1 in the contact position shown by means of cold welding produced. In other words, the aluminum wires are welded in the contact position with the contact element 1.

In principle, the contact surfaces 2 a, 3 a surrounding the aluminum screen mesh 7 in any case achieve a uniform contacting of all aluminum wires, if possible, without radial compression, such as crimping, or additional welding being necessary. Nevertheless, the electrical contact can be produced by simply pushing together or compressing the sleeves 2, 3.

Two possible geometric configurations of the contact surfaces 2a, 3a, which achieve the two effects mentioned above, will be discussed in detail below.

FIG. 3 shows an axonometric view of a first embodiment of the system according to the invention in an intermediate position in which the contact surfaces 2a, 3a of the sleeves 2,3 are not yet in contact with the aluminum screen mesh 7. It can be seen clearly that the first contact surface 2a of the inner sleeve 2 is conical, so that the size of the cross sections or diameter normal to the conductor axis 15 along the entire longitudinal extent of the sleeves 2.3 change. In other words, both contact surfaces 2a, 3a run obliquely to the conductor axis 15. Likewise, it can be seen that the contact surface 2a has two sections of different pitch, which merge into one another at a kink 12. In this case, the contact surface 2a in a first, in the present illustration of the outer sleeve 3 facing portion on a larger opening angle, is therefore steeper than in the second section.

FIG. 4 shows one too FIG. 3 analogous axonometric view of a second embodiment of the system according to the invention in the intermediate position. Here it can be seen that the first contact surface 2a of the inner sleeve 2 consists of three cylindrical sections of different sizes or diameter, wherein two first stages 13 each separate two successive sections from each other.

In FIG. 5 is a contact element 1 of the first embodiment, in FIG. 6 a contact element 1 of the second embodiment, that is, in each case the inner sleeve 2 and the outer sleeve 3, shown in detail. It can be seen immediately that inner sleeve 2 and outer sleeve 3 each have a through opening and that the inner sleeve 2 is at least partially inserted into the outer sleeve 3. The passage opening of the inner sleeve 2 is formed as a cable bushing 11, through which the cable 4 is feasible. The first contact surface 2 a of the inner sleeve 2 is formed by an outer circumferential surface of the inner sleeve 2.

The passage opening of the outer sleeve 3 is formed as an insertion volume 9 for receiving an insertable portion 10 of the inner sleeve 2 and further serves to pass the cable 4. In the present embodiment, the insertable portion 10 includes the entire extension of the inner sleeve 2, so that the inner sleeve 2 in the contact position completely absorbed in the outer sleeve 3. In alternative embodiments, it is also conceivable that the insertable portion 10 includes only a part of the longitudinal extent of the inner sleeve 2, so that a part of the inner sleeve 2 protrudes in the contact position of the outer sleeve 3 also. The second contact surface 3a is formed by an inner peripheral surface of the outer sleeve 3a and limits the insertion volume 9.

In both exemplary embodiments, it can be seen that the geometry of the first contact surface 2a corresponds to that of the second contact surface 3a, in that between the contact surfaces 2a, 3a the aluminum screen braid 7 can be clamped or cold-welded.

In FIG. 5 the conicity of the first contact surface 2a described above in connection with the first exemplary embodiment is again shown together with the kink 12. In addition, now the conical design of the second contact surface 3a of the outer sleeve 3 can be seen. In the present embodiment, the opening angles of the cones of the contact surfaces 2a, 3a differ from each other, so that when inserting the inner sleeve 2 in the outer sleeve 3 and when pushing the outer sleeve 3 on the inner sleeve 2, a wedge-shaped cross-sectional constriction is achieved. The kink 12 defines that region in which a clamping force is exerted on the aluminum wires by the contact surfaces 2a, 3a or in which a pressure peak for crushing / shearing and cold welding of the aluminum wires is formed. The area is thus a circumferential contact edge defined by the kink.

In FIG. 6 By contrast, the first steps 13 of the first contact surface 2 a described above in connection with the second embodiment variant can be seen. Now, the second contact surface 3a is also shown, which has with the first stages 13 cooperating second stages 14, which divides the second contact surface 3a in three sections. When inserting the inner sleeve 2 into the outer sleeve 3 or when pushing the outer sleeve 3 onto the inner sleeve 2, a wedge-like cross-sectional constriction is again achieved by the interaction of the steps 13, 14. In other words, the steps 13, 14 define the region in which a clamping force is exerted on the aluminum wires by the contact surfaces 2a, 3a or in which a pressure peak for crushing / shearing and cold welding of the aluminum wires is formed. In this embodiment, a circumferential contact edge is formed by each of the stages 13, 14, which constitutes the above-mentioned range.

The FIGS. 7a, b, c . d and 8a . b, c, d show different positions of the contact element 1 and the inner sleeve 2 and the outer sleeve 3 during the contacting process, wherein in the the former figures a system according to the first embodiment and in the latter figures, a system according to the second embodiment is shown.

In a first step (to see in FIGS. 7a, 7b or 8a, 8b) in each case the outer sleeve 3 is pushed onto the electrically conductive cable 4. The outer sleeve 3 is thereby pushed beyond the stripped area, so that the outer sleeve 3 comes to rest over the secondary insulation 8. In order to be able to ensure that the outer sleeve 3 can be pushed onto the secondary insulation 8, the smallest diameter of its passage opening is greater than or equal to the diameter of the cable 4 together with secondary insulation 8. In other words, the cable 4 is partially accommodated in the insertion volume 9 of the outer sleeve 3.

The second step (pictured in the FIGS. 7b, 7c and 8b, 8c ) is that the inner sleeve 2 is pushed onto the electrically conductive cable 4. In this case, the smallest diameter of the cable bushing 11 is greater than or equal to the diameter of the cable 4 together with the primary insulation 6, so that the inner sleeve 2 can be pushed onto the primary insulation 6.

As in the FIGS. 7c and 8c can be seen, the inner sleeve 2 is inserted between the primary insulation 6 and the aluminum braid 7, so that the aluminum braid 7 contacts the first contact surface 2a. It is also conceivable that the aluminum braided screen 7 is lifted in a separate step from the primary insulation 6 and after pushing the inner sleeve 2 is placed on the first contact surface 2a, for example by means of the step described below or in a separate step.

In the last step, the outer sleeve 3 is then displaced in the direction of the inner sleeve 2 until in the contact position the second contact surface 3a and the first contact surface 2a contact the aluminum screen mesh 7 and the aluminum wires of the aluminum screen mesh 7 between the Contact surfaces 2a, 3a are clamped and the electrical contact between the contact element 1 and the aluminum screen mesh 7 is made. Here, in the first embodiment, the wedge-shaped taper or the kink 12 and in the second embodiment, the steps 13, 14 that portion of the contact surfaces 2a, 3a, in which in the contact position, the clamping force is exerted on the aluminum screen mesh 7.

Upon further compression of the inner sleeve 2 and the outer sleeve 3, pressure peaks develop at the bend 12 or at the steps 13, 14 (ie at the circumferential contact edges), which first lead to compression and further compression to at least partial pinching or shearing. preferably a complete shearing that lead aluminum wires, so that a cold welding of the aluminum wires of the aluminum screen braid 7 takes place with the contact element 1. By squeezing or shearing the aluminum wires, the surface of the aluminum wires having the oxide layer is broken, thus breaking the oxide layer and preventing reformation of the oxide layer, thus ensuring a high temperature electrical connection between the aluminum screen braid 7 and the contact element 1, when the aluminum wires are cold-welded after being pressed in the contact position with the contact member 1.

As a rule, one of the two sleeves 2, 3, ie either the inner sleeve 2 or the outer sleeve 3, is designed as a contact sleeve, which is made of copper or a copper alloy and preferably a corrosion-inhibiting coating, for example of nickel and / or tin or alloys from it. About this contact sleeve of the potential equalization of the aluminum shield braid 7 is possible with a mass in which the contact sleeve by means of a compensation conductor is electrically connected to the ground. The other sleeve is formed as a support sleeve and is made of aluminum or an aluminum alloy to reduce the corrosion of the aluminum wires.

It goes without saying that any combination of the first and second embodiments are also suitable for achieving the same technical effects. Also, geometries deviating from the geometry of the contact surfaces 2 a, 3 a shown in the exemplary embodiments are conceivable if they permit clamping or compression / shearing of the aluminum wires of the aluminum screen mesh 7.

In FIG. 9 a third embodiment of the contact system according to the invention is shown, in which the inner sleeve 2 is seated in the contact position on the secondary insulation 8. In order to be able to clamp the aluminum braided screen 7 between the contact surfaces 2a, 3a, a section of the aluminum screen braid 7 has been pushed back over the first contact surface 2a. The outer sleeve 3 is in the axial direction, ie in the direction of the conductor axis 15, pushed onto the inner sleeve 2 to allow the clamping or compression / shearing of the aluminum wires of the aluminum screen mesh 7 between the two contact surfaces 2a, 3a.

The method for contacting the aluminum screen mesh 7 with the contact element 1 differs due to the different structure of the contact systems of the previously described in connection with the first two embodiments variants: In a first step, the inner sleeve 2 on the open end of the electrically conductive cable 4 postponed and pushed over the stripped area on the secondary insulation 8. If the first contact surface 2a - as in the illustrated embodiment - has areas with different sized cross-section, it is advantageous if the area with the smallest cross-section is directed towards the open end of the cable 4. In the present exemplary embodiment, the contact surfaces 2 a, 3 a are conical, as in the first and fourth exemplary embodiments, but it is equally conceivable for the contact surfaces 2 a, 3 a to be analogous to the second Embodiment stages have or a combination of slopes and steps. In the present embodiment, the inner sleeve 2 is flush with the secondary insulation 8, wherein a left-side or right-side offset is conceivable. Subsequently, an exposed by the stripping portion of the aluminum screen mesh 7 is folded over the first contact surface 2a, so that the aluminum screen mesh 7 is folded back and rests on the first contact surface 2a. In the last step, the outer sleeve 3 is then displaced from the direction of the open end of the cable 4 in the direction of the inner sleeve 2, so that the aluminum braid 7 is first clamped between the contact surfaces 2a, 3a and further compressed by axial compression and cold-welded. By such a configuration, conventional methods in which a folding of the aluminum screen mesh 7 is provided, in a simple manner with the aluminum advantageous clamping or cold welding by telescoping or compressing the sleeves 2.3 combine.

FIG. 10 shows a fourth embodiment of the contact system according to the invention, which is constructed similar to the previously described third embodiment. In this case, the inner sleeve 2 is seated in the contact position, in contrast to the previously described embodiment, not on the secondary insulation 8, but on an exposed portion of the aluminum screen mesh 7. The aluminum screen mesh 7 is thus exposed or stripped over a larger area than turned over becomes.

The method for contacting the aluminum screen braid 7 is carried out analogously to the method described above, wherein the inner sleeve 2 is just pushed onto the exposed portion of the aluminum screen braid 7 and over the inner sleeve 2 projecting portion of the aluminum screen braid 7 on the first contact surface 2a is handled. The sliding of the outer sleeve 3 is carried out as previously described. The like Design allows a particularly space-saving arrangement of the contact element 1 in the contact position. Only by telescoping or compressing the sleeves 2, 3 according to the invention for making the contacting is it possible to rest the inner sleeve 2 on the aluminum braided screen 7, since the aluminum braided shield 7 underlying the inner sleeve 2 could be damaged in conventional radial pressing operations. In addition, the secondary insulation 8 can be used as a stop for positioning the inner sleeve 2.

LIST OF REFERENCE NUMBERS

1

contact element

2

inner sleeve
2a first contact surface

3

outer sleeve
3a second contact surface

4

electrically conductive cable

5

inner conductor

6

primary insulation

7

Aluminum braided shield

8th

Secondary insulation

9

Einführvolumen

10

insertable section

11

Grommet

12

kink

13

first stage

14

second step

15

conductor axis

Claims (15)

Contact system for contacting an aluminum screen braid (7) with a contact element (1) comprising - An electrically conductive cable (4) having an electrical inner conductor (5), a primary inner insulation (6) surrounding the electrical inner conductor (5) and a secondary insulation (8) surrounding the primary insulation (6); - A plurality of aluminum wires comprising aluminum screen braid (7) which at least partially between the primary insulation (6) and the secondary insulation (8) of the electrically conductive cable (4) is arranged to extend; the contact element (1) which can be pushed onto the electrically conductive cable (4) and which comprises an outer sleeve (3) and an inner sleeve (2) which can be inserted at least in sections into the outer sleeve (3), wherein the inner sleeve (2) has a first
Contact surface (2a) and the outer sleeve (3) have a second contact surface (3a) for contacting the aluminum screen braid (7),
wherein the first (2a) and / or second contact surface (2a, 3a) has regions of different cross-section with respect to a conductor axis (15) of the electrically conductive cable (4),
and wherein the contact surfaces (2a, 3a) are formed such that the aluminum wires of the aluminum screen mesh (7) in a contact position of the contact part (1) by axially telescoping inner sleeve (2) and outer sleeve (3) between the contact surfaces (2a, 3a) clamped and contacted with the contact part (1),
characterized in that the first (2a) and the second contact surface (3a) are conical, wherein the opening angle of the cones are at least partially different sizes. Contact system according to claim 1, characterized in that the contact surfaces (2a, 3a) are further formed such that in the contact position of the contact element (1) by axially compressing the outer sleeve (3) and inner sleeve (2) a crushing / shearing of the aluminum wires Aluminum screen braid (7) and cold welding of the aluminum wires of the aluminum screen braid (7) with the contact element (1) takes place. Contact system according to one of claims 1 to 2, characterized in that the second contact surface (3a) of the outer sleeve (3) defines an insertion volume (9) for the inner sleeve (2) and the first contact surface (2a) of the inner sleeve (2) by a in the insertion volume (9) insertable portion (10) of the inner sleeve (2) is formed. Contact system according to claim 3, characterized in that the insertion volume (9) and / or insertable portion (10) with respect to the conductor axis (15) taper at least in sections. Contact system according to one of claims 3 to 4, characterized in that the inner sleeve (2) is completely received in the contact position in the insertion volume (9) of the outer sleeve (3). Contact system according to one of claims 1 to 5, characterized in that the first (2a) and / or the second contact surface (3a) in the contact position at least sections are formed running obliquely to the conductor axis (15). Contact system according to one of claims 1 to 6, characterized in that the first (2a) and / or the second contact surface (3a) has at least one kink (12). Contact system according to one of claims 1 to 7, characterized in that the first (2a) and / or the second contact surface (3a) has at least one step (13, 14). Contact system according to one of Claims 1 to 8, characterized in that the first contact surface (2a) has at least one first stage (13) and the second contact surface (3a) has at least one second stage (14), the stages (13, 14) each form a peripheral contact edge and the aluminum screen mesh (7) is contacted in the contact position of the contact edges. Contact system according to one of claims 1 to 9, characterized in that the inner sleeve (2) and / or the outer sleeve (3) made of copper or a copper alloy is made. Contact system according to one of claims 1 to 10, characterized in that one of the sleeves (2,3) made of copper or a copper alloy is made and the respective other sleeve (3,2) made of aluminum or an aluminum alloy or stainless steel. Contact system according to one of claims 10 to 11, characterized in that the made of copper or a copper alloy sleeve (2,3) has a corrosion-inhibiting coating. Contact system according to one of claims 1 to 12, characterized in that the secondary insulation (8) at least is removed in that region of the electrically conductive cable (4), in which the contact element (1) is arranged in the contact position,
wherein the region having the smallest cross-section of the first contact surface (2a) adjoins the region of the cable (4) having the secondary insulation (8). Contact system according to one of claims 1 to 13, characterized in that the inner sleeve (2) is arranged in the contact position between the primary insulation (6) and the aluminum braided shield (7). Contact system according to one of claims 1 to 12, characterized in that the aluminum braided shield (7) on the first contact surface (2a) of the inner sleeve (2) is folded over and a cable bushing (11) of the inner sleeve (2) the secondary insulation (8). or the aluminum braid (7) contacted.

Images