DE102014216832B3 - cable connection - Google Patents

Abstract

The present invention relates to a cable connection for connecting a first electrical cable (10) to a second electrical cable (20). The connection is made via a cable connection piece (30), which has two opposite contact surfaces (31, 32) which are respectively welded to the end faces (13, 23) of the compressed strands of the first and second electric cables (10, 20) around the two cables (10, 20) to connect together.

Description

1. Field of the invention

The present invention relates to cable connections for connecting two electrical cables to each other, and to a method for producing such a connection.

2. Background of the invention

Electrical cables are used to transmit electrical current and typically consist of one or more electrical conductors, which are also called wires or strands, which are covered by an insulating plastic sheath. The electrical conductors are typically made of copper or copper alloys. In this case, determines the type of material and the diameter of the electrical conductor assembly, the power transmission capacity of the cable. Especially for heavy current applications, large conductor cross sections are needed, which makes the cables used heavy and expensive. In automotive applications for, for example, hybrid or electric vehicles, relatively large amounts of such high current or voltage cables are needed. To reduce weight and cost, therefore, aluminum is often chosen as the material for the electrical conductors in such applications. In particular, aluminum alloys are used, so that when aluminum is used as the material, aluminum alloys are always explicitly included.

In the application of electrical cables, it is necessary to connect them to other components, for example at one end to an electrical energy source and at the other end of the cable to an electrical consumer. For this purpose, the cable ends must be assembled, d. H. be provided with suitable connections. In the simplest case and with small diameter electrical cables, suitable crimp sleeves are used for this purpose. For this purpose, a part of the insulation is removed at the free end of the cable and pressed a metallic crimp on the exposed strands or wires. For strain relief, the crimp sleeves typically have further regions with which the sleeve can also be crimped or pressed over part of the insulation. In particular, in the assembly of electrical cables with a relatively large diameter, d. H. Cables that are designed for high currents or voltages, a simple crimp connection is often unsatisfactory. This is particularly the case with the use of aluminum conductors, as the aluminum tends to oxidize in the air, thereby adversely increasing the electrical resistance in the transition from the conductor to the material of the crimp barrel.

From the EP 1 032 077 a method is known in which in a first step, a crimping sleeve, referred to therein as a support sleeve, is pressed onto a free end of a cable to compress the strands. The insulation at the free end is partially removed for this, so that the sleeve is in direct contact with the exposed strands and the rear portion of the sleeve is pressed onto the insulation to achieve a strain relief. The crimp or support sleeve itself does not have its own connection means. Instead, it is proposed that a connection part, z. B. with a battery terminal, a cable lug, a plug part o. Ä. to weld with the formed from the individual wires or strands front side of the end of the aluminum cable. As a preferred welding process while friction welding is to be used, wherein the connecting part is set in rotation and the cable and the pressed support sleeve is pressed against the rotating connector, wherein in known manner by the resulting frictional heat after braking the rotation of the connecting part, the two parts together fused or welded. In this way, on the one hand a simple connection is to be achieved, on the other hand, the exposed strands or wires are protected from oxidation. This has the disadvantage that the connection parts used are already configured for a specific purpose, such as for a precisely specified contact on a vehicle battery, so that the once fully configured cables are always suitable only for a specific application.

With the known methods, it is possible to provide the free ends of electrical cables with suitable connection elements, such as cable lugs or battery terminals or the like, so that the cables can be connected to electrical consumers or an electrical energy source. In many cases, however, it is desirable to connect two cables by themselves, i. H. without having an electrical load or an electrical energy source interposed therebetween. With the previously known methods, this is only cumbersome.

In the light of this known prior art, the present invention thus has the object to provide a cable connection for connecting two electrical cables together, which is simple, safe and inexpensive. Another object is to provide a corresponding method for connecting two electrical cables together.

These and other objects, which will become apparent upon reading the present specification or which may be recognized by those skilled in the art, are achieved by a cable joint according to claim 1 and a method of making a joint of two cables according to claim 7.

3. Detailed description of the invention

According to the present invention, a cable connection is provided for connecting two electrical cables, i. H. for connecting a first electrical cable to a second electrical cable. The first and second electrical cables each have a plurality of strands, d. H. more than one, which are covered by an insulation, so a cable sheath. The invention is particularly suitable for the connection of cables, with which high currents or voltages can be transmitted, as typically occur in hybrid or electric vehicles when transmitting the necessary drive power to the electric motors. The cables can be single or multi-core. Each of the two cables has at its free end a crimping sleeve which compresses the strands. To improve the electrical contact can be provided that the cables are partially freed from the insulation at their free ends, so that the crimp sleeves are partially pressed onto the exposed strands and partly on the insulation, d. H. the cable sheath. This also ensures a particularly stable connection. According to the invention, a cable connecting piece is provided which has two contact surfaces, preferably arranged parallel to one another, which are each welded to the end faces of the compressed strands of the first and second electrical cables so as to connect the two cables to one another.

In general, the welding preferably takes place in that the cable connection piece is brought into rotation and the cables are pressed after crimping with the end faces of the compressed strands against the rotating contact surfaces of the cable connection piece. Due to the resulting frictional heat, there is a fusion and thus welding of the stranded ends with the contact surface of the cable connection piece. This welding process is also referred to as friction welding.

Preferably, the connection of the two electrical cables thus produced is further secured with a mechanical strain relief, which is connected to the first and the second cable, for example, in order to mechanically relieve the cable connection piece. Such a mechanical strain relief may consist of a rigid clamp, which bridges, for example, the cable connector and is fixed next to the Crimphülsen to the insulation of the respective cable.

In a preferred embodiment, the cable connector has a measuring device that allows detection of the current flowing between the two cables. Such a measuring device can be used in particular for detecting the current intensity and / or the voltage. By way of example, a measuring coil which detects the current flow can be integrated in the cable connection piece. An evaluation unit can send the measurement data via radio or cable to a receiver site, eg. B. for measuring the sections of high voltage lines.

The two opposite contact surfaces of the cable connection piece are preferably parallel to one another. This arrangement allows for a coaxial connection of the two electrical cables with each other and it allows a particularly simple clamping of the cable connection piece in order to enable this for a friction welding operation in rotation.

In general, the crimp sleeves end in the same plane in which the end faces of the compressed strands end so that the welded connection encompasses the crimp sleeves. Advantageously, the welded connection should be formed between connection piece, strands and crimp sleeves in such a way that the entry of moisture and / or air to the end faces of the strands is prevented. This has particular advantages when used as a material for the conductor of the cable aluminum, which otherwise tends to oxidize, thereby increasing the electrical resistance at the connection points.

The invention also relates to a method for producing a connection of a first electrical cable to a second electrical cable. The two cables are each provided with a plurality of strands, ie more than one strand, which are comprised of an insulation. In a first step, a crimp sleeve is pressed onto one of the free ends of the first or second electrical cable to be connected in order to press the strands together. This is done on both electrical cables to be connected. In addition, a cable connector with two opposite parallel contact surfaces is provided. The end faces of the strands of the first cable are welded to the cable connection piece via the first of the two opposite parallel contact surfaces, and the end sides of the strands of the second cable are correspondingly welded to the second of the two opposite parallel contact surfaces of the cable connection piece. This can be done one after another or simultaneously. Preferably, this welding connection is carried out by friction welding, by the cable connection piece is set in rotation and the end faces of the strands are pressed against the contact surfaces. In this approach, it is advantageous to press both cables at the same time to their respective contact surfaces on the cable connector, since it is difficult to put the cable connector in the necessary rotation when one of the two cables is already attached.

4. Description of preferred embodiments

In the following, the present invention will be explained in more detail with reference to the attached figures. Hereby shows:

1a schematically the components of a cable connection according to the present invention prior to assembly;

1b the components of 1a after welding;

1c the construction of the 1b with an additional securing element;

2a the embodiment of the 1c with an additional measuring device; and

2 B the embodiment of the 2a in a cut view.

In 1a the components for a cable connection are shown in a partially assembled condition. A first cable 10 is shown schematically on the left, which cable a jacket or an insulation 11 comprising a plurality of electrically conductive strands. At the free end of the first cable 10 is a crimp barrel 12 pressed on to squeeze the strands together. The insulation 11 is preferably at the free end of the cable 10 to about half of the crimp barrel 12 removed, leaving an electrical contact between the crimp barrel 12 and the exposed strands. The second half of the crimp barrel 12 is preferably pressed onto the existing insulation, whereby good pull-out forces arise and the construction is water-resistant. On the right side of the 1a is a second electrical cable 20 pictured, which also has a jacket or insulation 21 comprising a series of strands. A crimp barrel 22 is on the free end of the cable 20 pressed to squeeze the strands together. In 1a are the front ends 23 the compressed strands recognizable. Analog also points the first cable 10 front sides 13 the strands, which preferably all end in a plane as shown.

Between the first and second cable is a cable connector 30 , which is a first contact surface 31 and a second contact surface 32 having. The two contact surfaces are opposite each other and are parallel to each other and substantially planar. To connect the two electrical cables 10 and 20 Together, the cable connector 30 preferably rotated and the two cables 10 and 20 become from the left or right against the first contact surface 31 or the second contact surface 32 pressed. This is preferably done simultaneously. By the rotation of the cable connection piece 30 Friction heat is generated, which leads to a fusion or welding of the strands and the end faces of the Crimphülsen 12 and 22 with the contact surfaces 31 and 32 leads.

In 1b the finished welded assembly is shown. Since the cable connector is preferably made of a highly electrically conductive material, power from the first cable 10 to the second cable 20 flow or vice versa. As material for the cable connection piece 30 For example, copper or aluminum is suitable or other suitable alloys.

In 1c a preferred embodiment is shown in which the cable connection according to 1b is provided with an additional securing element, namely with a mechanical strain relief 40 , The mechanical strain relief 40 It consists essentially of a sturdy U-shaped bent metal bracket, two clamps 41 and 42 that has to do with the insulation 11 of the first cable 10 and the insulation 21 of the second cable 20 are stuck. The mechanical strain relief 40 is particularly useful with freely suspended cables, since here the forces acting on the welding between the cable and cable connector are unfavorable.

In 2a a further preferred embodiment is shown in which the cable connection piece 30 with a transducer 50 is provided. The sensor 50 acts with a measuring coil 51 (in 2 B shown) together, for example, the current or voltage through the cable 10 and 20 to measure flowing electricity. The sensor 50 can send the transmitted data, for example via radio or cable to a recipient site, so that z. B. simply track sections can be monitored at high voltage lines.

LIST OF REFERENCE NUMBERS

10

first cable

20

second cable

11, 21

Jacket or insulation

12, 22

crimp barrel

13, 23

End faces of the strands

30

Cable connector

31

first contact surface

32

second contact surface

40

mechanical strain relief

41, 42

clamp

50

transducer

51

measuring coil

Claims (8)

Cable connection for connecting a first electrical cable ( 10 ) with a second electrical cable ( 20 ), comprising: - first and second electrical cables ( 10 . 20 ), each having a plurality of strands which are insulated from ( 11 . 21 ) are included; - first ( 12 ) and second ( 22 ) Crimp sleeves, each on a free end of the first and second electrical cable ( 10 . 20 ) are compressed to compress the strands; and - a cable connector ( 30 ), characterized in that the cable connection piece ( 30 ) two opposing contact surfaces ( 31 . 32 ), each with the end faces ( 13 . 23 ) of the compressed strands of the first and second electrical cables ( 10 . 20 ) are welded to the two cables ( 10 . 20 ) to connect with each other. Cable connection according to claim 1, characterized in that the connection further comprises a mechanical strain relief ( 40 ) connected to the first and second cables ( 10 . 20 ) is connected to the cable connector ( 30 ) mechanically relieve. Cable connection according to one of the preceding claims, characterized in that the cable connection piece ( 30 ) via a measuring device ( 50 ), which provides a detection of the between the two cables ( 10 . 20 ) flowing current, in particular a detection of the current and / or voltage. Cable connection according to one of the preceding claims, characterized in that the two opposite contact surfaces ( 31 . 32 ) are parallel to each other. Cable connection according to one of the preceding claims, characterized in that the welded connection the Crimphülsen ( 12 . 22 ) with. A method of making a connection of a first electrical cable to a second electrical cable, comprising: - Providing a first electrical cable with a plurality of strands, which are covered by an insulation; - Providing a second electrical cable with multiple strands, which are covered by an insulation; - Pressing a crimp barrel on each free end to be connected to the first and second electrical cable to compress the strands; - Providing a cable connector with two opposite parallel contact surfaces; - Welding of the cable connection piece via the first of the two opposite parallel contact surfaces with the end face of the strands of the first cable, and - Welding of the cable connection piece via the second of the two opposite parallel contact surfaces with the end face of the strands of the second cable. Method according to the preceding claims, characterized in that the welded connection is effected by friction welding, by the cable connection piece is set in rotation and the end faces of the strands are pressed against the contact surfaces. Method or cable connection according to one of the preceding claims, characterized in that the electrical cables are aluminum cables.

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