EP3496208A1 - Contact device and contact system for coaxial high voltage cable - Google Patents

Abstract

A contact device (100) for contacting a cable is proposed. The cable has an electrical conductor which is surrounded by a screen formed as a tube. The contact device comprises a contact tube (101) receiving the cable and having at least one threaded hole (106A, 106B) with a clamping screw (107A, 107B) received therein contacting the shield of the cable. Furthermore, a contact system is proposed which comprises the contact device and the cable, as well as production methods for the contact device and the contact system.

Description

area

The invention relates to a contact device for contacting a coaxial cable, the electrical conductor is surrounded by a screen, which is designed as a tube, in particular as a corrugated tube. Furthermore, the invention relates to a contact system comprising a contact device according to the invention. In addition, the invention relates to methods for producing a contact device according to the invention and a contact system according to the invention.

background

Contact devices and contact systems of the type mentioned are required for example in cable fittings for a coaxial cable. A cable set is a component that terminates an electrical cable or connects it to another cable.

A cable set is intended to make good electrical contacts to the conductor and shield of the coaxial cable while preventing moisture or dirt from getting between the components of the cable. In addition, the electrical insulation between the electrical conductor and the screen of the coaxial cable must be ensured. As a shield, a corrugated pipe is often used in this type of cable. The connection of such a high-voltage cable, for example, to the housing of an electrical set or to another high-voltage cable thus requires the contacting of both the cable core and the shield. When moving to other components, the electrical conductor should also be mechanically stable to the corresponding component.

A common method for the current-carrying contact of corrugated metal (corrugated) is the welding or soldering of metal contact elements. This type of contacting is demanding and time-consuming. In addition, the quality of the contact strongly depends on the skills of the assembly personnel making the contact. A consistently high quality of the contacts is therefore not easy to achieve with conventional contacting methods.

On this basis, an object of the present invention to provide a contact device which overcomes or at least improves one or more of the problems mentioned above.

Summary of the invention

To achieve this object, the invention proposes according to a first aspect, a contact device for contacting a cable with an insulated electrical conductor, which is surrounded by a screen which is formed as a tube. The contact device has a contact tube which receives the cable. The contact device is characterized in that the contact tube has at least one threaded hole with a clamping screw received therein, which contacts the screen of the cable.

A clamping contact between the shield of the cable and the contact tube has the advantage that this type of contacts compared to welding or soldering is easy to manufacture and also offers advantages in terms of occupational safety. At the same time it is possible to achieve a more uniform quality of electrical contacts with terminal contacts, which hardly depends on the skill and skill of the assembly staff. Another advantage of clamp contacts is that almost any metallic materials can be combined together to make electrical contact. Furthermore, only simple tools are necessary for the production of a clamping contact.

In an advantageous embodiment, a plurality of threaded holes, each with a clamping screw are provided in the contact device, which are arranged distributed uniformly on a circular line on the circumference of the contact tube.

This arrangement of the clamping screws is advantageous because a cable can be arranged centrally in the contact device in a simple manner. This arrangement has in the case of a short circuit between the conductor of the cable and the contact tube the advantage that the resulting electrodynamic forces cancel each other, whereby the mechanical stress of the contact device is limited.

In an advantageous embodiment of the contact device, the threaded holes are arranged uniformly distributed on each circle with one clamping screw on at least two circular lines on the circumference of the contact tube. Advantageously, in this case, the threaded holes are offset on adjacent circular lines in the circumferential direction to each other. In this way, it is achieved that no structural weaknesses occur in the jacket of the contact tube. In addition, the contact pressure of the clamping screws is evenly distributed on the screen of the cable.

The contact tube of the contact device can expediently have a fastening flange at one end in order to fasten the contact device, for example, to an electrical system or a cable fitting.

In a further development of the invention, the contact device has at least one contact point, which allows the connection of cables or strands, e.g. for grounding the contact device. In this case, the contact point may expediently be formed as a pin which has an internal thread or an external thread in order there to be e.g. to screw on a cable lug or similar. It is also conceivable that the pin has a threaded pin with external thread for attachment of secondary contact elements.

According to a second aspect, the invention proposes a contact system comprising a contact device according to the invention and a cable having an electrical conductor which is surrounded by a screen which is formed as a tube.

The contact system has the same advantages already described in connection with the contact device.

• Bereitstellen eines Kontaktrohres;
• Herstellen von gleichmäßig beanstandeten radialen Löchern auf einer Kreislinie in einem Mantel des Kontaktrohres und
• Schneiden von Gewinde in die zuvor gebohrten Löcher.

In one embodiment, the shield of the cable is formed by the contact system as a smooth tube jacket or a corrugated tube jacket. Which type of jacket is chosen depends on the application. In principle, a corrugated tube casing has a higher flexibility than a smooth tube casing.
According to a third aspect, the invention proposes a method for producing a contact device according to the invention. The method comprises:

• Providing a contact tube;
• Producing evenly spaced radial holes on a circular line in a jacket of the contact tube and
• Cutting threads in the previously drilled holes.

According to a development of the manufacturing method for the contact device, the radial holes are produced by a friction-flow-drilling process, by deep drawing or by attaching a rivet nut.

The mentioned method for producing the radial holes have the advantage that a greater material thickness compared to the wall thickness of the contact tube for the thread is available and thus the length of the threaded hole is greater and a better grip of the clamping screw is achieved in the contact tube. This makes it possible, for example, to transfer larger clamping forces with the clamping screws.

• Bereitstellen einer Kontaktvorrichtung nach einem der vorstehenden Ansprüche;
• Entfernen eines äußeren Mantels von einem Kabel mit einem als Rohr ausgebildeten Schirm, um den Schirm freizulegen;
• Einführen des Kabels in die Kontaktvorrichtung; und
• Eindrehen der Klemmschrauben, um den Schirm zu kontaktieren.

Finally, according to a fourth aspect, the invention proposes a method for producing a contact system. The method comprises:

• Providing a contact device according to one of the preceding claims;
• Removing an outer jacket from a cable having a shielded tube to expose the shield;
• Inserting the cable into the contact device; and
• Screw in the clamping screws to contact the screen.

Short description of the drawing

Fig. 1

eine perspektivische Ansicht einer erfindungsgemäßen Kontaktvorrichtung;

Fig. 2A

einen Querschnitt der Kontaktvorrichtung aus Figur;

Fig. 2B

ein vergrößerter Ausschnitt aus Figur 2A;

Fig. 3

den Aufbau eines Kabels, das mit der Kontaktvorrichtung kontaktiert wird;

Fig. 4

die Kontaktvorrichtung aus Figur 1 in einer Draufsicht mit einem montierten Kabel;

Fig. 5

ein Flussdiagramm mit den Verfahrensschritten zur Herstellung einer erfindungsgemäßen Kontaktvorrichtung; und

Fig. 6

ein Flussdiagramm mit den Verfahrensschritten zur Herstellung eines erfindungsgemäßen Kontaktsystems.

The invention will be explained in more detail by way of example with reference to an embodiment with reference to the accompanying figures. All figures are purely schematic and not to scale. Show it:

Fig. 1

a perspective view of a contact device according to the invention;

Fig. 2A

a cross section of the contact device of Figure;

Fig. 2B

an enlarged section FIG. 2A ;

Fig. 3

the construction of a cable which is contacted with the contact device;

Fig. 4

the contact device FIG. 1 in a plan view with a cable mounted;

Fig. 5

a flowchart with the method steps for producing a contact device according to the invention; and

Fig. 6

a flow chart with the method steps for producing a contact system according to the invention.

The same or similar elements are provided in the figures with the same or similar reference numerals.

embodiment

FIG. 1 shows a perspective view of a contact device 100 having a contact tube 101. The contact tube 101 has in different embodiments, a diameter of 10 - 20 cm and a height of 10-30 cm. If necessary, these dimensions may also be chosen differently in order to adapt the contact tube 101 to certain applications. At the in FIG. 1 underlying end of the contact tube 101 is at the contact tube a flange 102 welded. The flange 102 is provided along its circumference with mounting holes 103 for receiving fastening screws (not shown) for attaching the contact device to an electrical device, such as a transformer or a cable set (in FIG. 1 not shown). The contact tube 101 and the flange 102 are made of aluminum or an aluminum alloy. In principle, other metals come into question, for example, copper or other highly conductive metals.

In the jacket 104 of the contact tube 101, threaded holes 106A and 106B are provided, each receiving a clamping screw 107A and 107B, respectively. The threaded holes 106A are along a circular line 108A, and the threaded holes 106B are circumferentially equally spaced along a circular line 108B. Although in FIG. 1 two circular lines 108A and 108B are shown, in other embodiments, the threaded holes may also be arranged on only a single circular line or on more than two circular lines. The relevant embodiment of the contact device 100 according to the invention depends on the particular application, in particular how many clamping screws are required.

In any case, the threaded holes are arranged on different circular lines preferably offset from one another. At the in FIG. 1 A threaded hole 106B on the circular line 108B is located in the circumferential direction exactly between two threaded holes 106A located on the circular line 108A. This avoids that, along axial directions, the jacket 104 of the contact tube 101 is structurally weakened by bores arranged one behind the other.

The contact device 100 further comprises a radially projecting pin 111 which is welded to the jacket 104 of the contact tube at a certain distance between the flange 102 and the circular line 108B and a contact point for connecting a further cable forms. For this purpose, the pin 111 has a central threaded hole 112, for example, to tighten a cable lug of the other cable.

In the FIG. 1 shown screws 107A, 107B are provided with a hexagon socket. In principle, other types of screws can be used for the present invention, in particular screws with a tear-off.

FIG. 2A shows a cross section through the contact tube 101 at the level of the circular line 108B. In this view, it can be clearly seen that the threaded holes 106B are evenly distributed on a circumferential line of the shell 104 of the contact tube 101.

FIG. 2B shows an enlarged section FIG. 2A and illustrates a manufacturing specificity of the contact tube 101. The holes for the threaded holes are made by a friction flow-drilling process. In this case, a rapidly rotating steel tool is pressed in the radial direction onto the jacket 104 of the contact tube 101. The frictional heat causes the metal to flow in a state that forces the material under the rotating tool. In this case, around the bores in the contact tube 101, beads 201 are formed around the respective borehole, which are directed inward in the radial direction in the contact tube 101. This results in a borehole whose length I is greater than the thickness d of the shell 104 of the contact tube 101. A thread is cut in the borehole to produce a threaded hole, for example a threaded hole 106A or 106B. The length of the threaded hole corresponds to the length I of the borehole. In contrast, the length of a threaded hole conventionally made with a twist drill would correspond to the length of the jacket thickness d of the contact tube 101. In comparison, the threaded hole in the contact tube according to the invention is mechanically more stable because of its greater length, so that it is possible to exert relatively larger clamping forces with the clamping screws 107A and 107B.

FIG. 3 schematically shows the structure of a high voltage cable 300 having an outer sheath 301. A screen 302 surrounds a multi-conductor conductor 303 formed of individual wires 304. The individual wires 304 are surrounded by a sheath 306, which bundles the individual wires 304 to the conductor 303. The screen 302 is formed as a corrugated pipe. The electrical conductor 303 is surrounded by a dielectric 307, which is followed by an insulating layer 308 which lies between the dielectric 307 and the screen 302. In other embodiments, the conductor 303 is formed as a solid single conductor.

FIG. 4 shows a cross-sectional view through the contact device 100 with a mounted HV coaxial cable 301, wherein the cut surface along the line 4-4 in FIG. 1 runs. It should be noted that in FIG. 4 in contrast to FIG. 1 the screws 107A and 107B are screwed into the threaded holes 106A and 106B of the contact tube 101, respectively. Of the cable 300, the outer sheath 301 is removed by a length approximately equal to the length of the contact tube 101 plus the length needed to connect the cable 301 inside an electrical device to a dedicated terminal. Inside the contact device 100, the corrugated tube 302 is exposed. The screws 107 A and 107 B are screwed, clamp the corrugated tube 302 substantially in the center of the contact tube 101 and establish an electrically conductive contact between the contact tube 101 and the corrugated tube 302 ago. This arrangement also has the advantage that in the event of a short circuit and high current flows through the conductor 303 and the contact tube 101, the resulting electrodynamic forces cancel each other out. In particular, however, the arrangement has the advantage that in a simple manner reproducible electrical contacts between the corrugated tube 302 and the contact tube 101 can be produced.

The arrangement of the clamping screws 107A and 107B, which are uniformly spaced apart in each case on a circle line 108A or 108B and which are offset relative to one another on different circular lines, leads inter alia also to the fact that the Clamping forces on the screen 302 are relatively evenly distributed, which has a favorable effect on the dimensional stability of the screen 302.

In FIG. 5 is a flowchart with the essential process steps for producing a contact tube 101 according to the invention shown schematically. In a first step S1, a cylindrical tube made of, for example, aluminum or an aluminum alloy is provided. In a next step S2 radial holes are drilled in the jacket 104 of the contact tube 101, which are equally spaced on a circular line on the circumference of the shell 104. The drilling of the holes is preferably carried out by a friction-flow-drilling process in which a rapidly rotating steel tool is pressed onto the jacket 104. As a result, the material of the shell goes into a flowable state, whereby on the one hand, a hole is formed and on the other hand, a bead 201 surrounding the hole is formed on the inside of the shell. Threads are cut in the holes thus formed to form threaded holes into which the contact screws 107A and 107B are screwed. If necessary, a flange 102 may be welded to the contact tube 101 before or after making the threaded holes 106A and 106B.

The contact device produced thus far is used for producing a contact system. The method steps for producing the contact system are shown schematically in a flowchart in FIG FIG. 6 shown. In a first step S10, a contact device 100 according to the invention is provided. Then, in a step S11, the outer jacket 301 is removed from the cable 300 to expose the shield 302 formed as a corrugated pipe. In a step S12, the cable 300 is inserted with the end into the contact device 100, on which the corrugated tube 302 is exposed. Finally, in step S13, the clamping screws 107A and 107B are screwed to contact the corrugated tube 302 in a substantially central position in the contact tube 101.

To complete the contacting, another cable can be connected to the pin 111, which can be fastened with a screw.

LIST OF REFERENCE NUMBERS

100

contact device

101

contact tube

102

mounting flange

103

mounting holes

106A, 106B

threaded holes

107A, 107B

clamping screw

108A, 108B

circle line

111

spigot

112

threaded hole

113

external thread

201

beads

300

electric wire

301

outer insulation jacket

302

umbrella

303

multicore conductor

304

individual wires

306

shell

307

dielectric

308

buffer layer

Claims (11)

A contact device (100) for contacting a cable (300) with an insulated electrical conductor (303) surrounded by a screen (302) formed as a tube, said contact device comprising a contact tube (101) connecting said cable (30). 300),
characterized in that
the contact tube (101) has at least one threaded hole (106A, 106B) with a clamping screw (107A; 107B) received therein contacting the shield (302) of the cable (300). Contact device according to claim 1, characterized in that a plurality of threaded holes (106A, 106B) each having a clamping screw (107A, 107B) are provided, which are arranged evenly distributed on a circular line (108A, 108B) on the circumference of the contact tube (101). Contact device according to claim 2, characterized in that the threaded holes (106A, 106B) are each secured with a clamping screw (107A, 107B) on at least two circular lines (108A, 108B) on the circumference of the contact tube (101) on each circular line (108A, 108B). are arranged evenly distributed. Contact device according to claim 3, characterized in that the threaded holes (106A, 106B) are offset on adjacent circular lines in the circumferential direction to each other. Contact device according to one of the preceding claims, characterized in that the contact device has at least one contact point, which allows the connection of cables or strands. Contact device according to claim 5, characterized in that the contact point as a pin (111) is formed, which has an internal thread or an external thread. A contact system comprising a contactor (100) according to any preceding claim and a cable (300) having an electrical conductor (303) surrounded by a screen (302) formed as a tube. Contact system according to claim 7, characterized in that the screen (302) is a smooth tube jacket or a corrugated tube jacket. A method of making a contactor according to any one of the preceding claims, the method comprising: - Providing a contact tube (101); - Producing evenly spaced radial holes on a circular line (108A, 108B) in a jacket (104) of the contact tube (101) and - Cutting threads in the previously drilled holes. A method according to claim 9, characterized in that the production of the radial holes by a friction-flow-drilling process, by deep drawing or by attaching a rivet nut takes place. A method of making a contact system, the method comprising: - Providing a contact device (100) according to one of the preceding claims; - removing an outer jacket (301) from a cable having a shield formed as a tube (302) to expose the screen; - inserting the cable (300) into the contact device (100); and - Screwing in clamping screws (106A, 106B) to contact the screen (302).

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