DE102014216833A1 - Cable connection for connecting an electric cable - Google Patents

Abstract

The present invention relates to a cable connection for connecting an electric cable (10) to an electrical contact element (40) and comprises an electrical cable (10) with a crimp sleeve (20) which is pressed onto a free end of the cable around the strands (14 ) of the cable. Further, a connection adapter (30) is provided, which has a contact surface (34) which is welded to the end faces of the compressed strands. The connection adapter (30) has a suitable connection form (32) on the side opposite the contact surface (34), with which a connection with a complementary connection form (42) of the electrical contact element (40) is possible in a simple and flexible manner.

Description

1. Field of the invention

The invention relates to cable connections for connecting electrical cables with other components, in particular for the connection of power cables.

2. Technical background

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.

The present invention therefore has the object to improve the prior art, and in particular to provide a simple and flexible cable connection for connecting an electrical cable to another component. In particular, the invention is intended to provide a flexible connector for an electrical cable which can be easily and safely connected to an electrical cable, particularly electrical high-voltage aluminum cables such as those used in automotive applications for hybrid and electric vehicles for transmission the electrical energy needed to the electric motors.

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 according to claim 9.

3. Detailed description of the invention

According to the present invention, a cable connection is provided for connecting an electrical cable, in particular an electrical aluminum cable for high currents or voltages, with an electrical contact element. The electrical contact element can be part of an electrical load or else a connection component configured for a specific purpose, such as a battery terminal, a cable lug, or the like, which is then used for connection to an electrical load or an electrical energy source. The affected electrical cables have multiple strands, d. H. more than one, which are covered by a suitable insulation. However, the electrical cable can also be a multi-core cable. On a free end of the cable, a suitable crimping sleeve is pressed, which compresses the individual strands at least in the region of the end side of the strands. Advantageously, the insulation is partially removed at this free end, so that the crimping sleeve is partially in direct, electrically conductive contact with the strands and is partially pressed onto the insulation. Furthermore, according to the invention, a connection adapter is provided, which has on one side a preferably planar contact surface, which is welded to the end faces of the compressed strands. This welding is preferably carried out by means of friction welding, wherein the connection adapter is set in rotation and the free end of the cable is pressed with the crimping sleeve against the rotating connection piece or the contact surface thereof. Due to the heat generated by the rotation, there is then a fusion or welding of the contact surface of the connection adapter with the end faces of the compressed strands. In order to allow flexible use, the connection adapter is provided at the opposite side of the contact surface with a connection shape having at least one surface which is aligned obliquely to the end side of the strands.

The connection form is preferably a simple geometric shape and is in particular a conical shape, such as a cone or a corresponding conical recess. The oblique surface increases the contact area compared to a simple planar contact surface, so that a good electrical transition is given. The electrical contact element, such as a battery terminal or a cable lug o. Ä., Is accordingly provided with a complementary connection form. This makes it possible to equip a provided with a terminal adapter according to the invention electrical cable with a variety of different electrical contact elements depending on the application.

In order to improve the mechanical connection between the connection adapter and the electrical contact element, a further securing element is preferably provided. Particularly preferably, this further securing element is provided in the form of a sleeve which at least partially surrounds the connecting piece and the further component. The sleeve may for example be a nut and the outer surfaces of the connection adapter or contact element are accordingly preferably provided with an external thread, so that the mother can be screwed on it.

When using a cone and a corresponding conical recess on the connection adapter and electrical contact element, it is advantageously possible to dimension them so that a frictional connection between them is possible. In other words, the shape and surface finish of the cone and the associated conical recess allow a so-called conical connection, as known from the design technique as a shaft-hub connection.

When using a cone or a conical recess, the opening angle α is preferably between 60 and 130 °, more preferably between 60 and 110 °, and most preferably between 70 and 100 °. As a suitable base area of the cone, regardless of the opening angle α, a diameter d of the cone of 0.7-1.3 times the diameter of the cable has been found, more preferably 0.8-1.2 times and most preferably from 0.9-1.1-fold. The diameter of the cable is understood here as the outside diameter of the cable, measured on the outside of the insulation.

Generally, preferably, the complementary connection form of the electrical contact element is set up such that it can be prestressed in the connection direction by means of a spring element. This results in a particularly advantageous electrical and mechanical contact between the surfaces of the connection form of the connection adapter and the complementary connection form of the contact element.

The present invention also relates to a method for producing a connection of an electrical cable with an electrical contact element. A person skilled in the art understands a contact element as a dedicated electrical connection, such as, for example, a battery terminal, a cable lug or a connection socket or the like. In the method according to the invention, in a first step, an electrical cable with a plurality of strands is provided, which are covered by insulation. Subsequently, a crimp barrel is pressed onto a free end of the cable, which previously for this purpose was advantageously at least partially stripped. Subsequently, a connection adapter as described above is provided and welded via its contact surface with the end faces of the compressed strands. In this case, preferably friction welding is used, for which the connection adapter is set in rotation and the front side of the strands is pressed together with the end face of the crimping sleeve against the rotating connection adapter.

4. Description of preferred embodiments

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

1 an electrical cable with crimped sleeve and a connection adapter before welding;

2 the parts of 1 in the assembled state;

3 in a schematic view the cable from 2 before being assembled with an electrical contact element; and

4 in a schematic, sectional view the parts of 3 in the connected state.

In 1 is an electrical cable in a schematic three-dimensional view 10 shown a coat (insulation) 14 and a number of electrically conductive strands 12 , The strands 12 are for example made of aluminum. On the free end of the cable 10 is a crimp barrel 20 pressed, which the strands 12 compresses. The coat 14 of the cable 10 For this purpose, it is preferably at least partially removed at the free end, so that an electrical contact between the strands 12 and the inside of the crimp barrel 20 consists. Next is in 1 a connection adapter 30 shown. The connection adapter 30 has a flat contact surface 34 on, against the front sides of the compressed strands 12 is directed. On the opposite side of the connection adapter is a connection form 32 intended. The connection form 32 is in the illustrated preferred embodiment a cone, ie the connection form has a conical shape. The cone has an opening angle α of about 90 ° and accordingly a slope angle β of about 45 °. The diameter d of the base of the cone shown corresponds approximately to the outer diameter of the cable 10 ,

In 2 is the connection adapter 30 with the cable 10 connected. This is the contact surface 34 with the faces of the compressed strands 12 as well as with the front of the crimp barrel 20 welded. This is preferably done via friction welding, wherein the connection adapter 30 is set in rotation and the cable 10 with the crimp barrel 20 against the contact surface 34 is pressed so that it due to the resulting frictional heat to a fusion or welding between the end faces of the strands 12 and the contact surface 34 comes. This in 2 Pre-assembled cables 10 now has a flexible connection adapter, which is a simple connection or connection of any electrical contact elements, such as contact sleeves, cable lugs, battery terminals, o. allowed. Depending on the desired application, it is thus easy to attach different contact elements. Since the contact elements are preferably detachable on the connection adapter 30 attachable, it is also possible to replace the contact elements when the cable 10 to be connected to another component, such as another consumer.

In 3 is the prefabricated cable 10 with the attached adapter 30 shown, as well as in a purely schematic representation of an electrical contact element 40 , The electrical contact element 40 For example, a battery terminal, a cable lug or a contact socket, o. Ä. be and the cylinder shape shown here to indicate this only schematically. Next is a fuse element 50 provided, which is the connection between connection adapter 30 and contact element 40 guaranteed. This is in 4 better to recognize.

In 4 are the components of 3 shown in a connected state in a sectional view. It can be seen that the contact element 40 a complementary form of connection 42 has, ie here a conical recess, which receives the cone (connection form) 32 of the connection adapter 30 is trained. The conical shape of the connection forms provides a large contact area, so that the electrical transition between the connection adapter and the contact element is very good. The fuse element 50 has an inwardly directed flange 52 on, which rests against the contact surface of the connection adapter. The inside of the fuse element 50 is with a thread 54 provided, which with an external thread of the electrical contact element 40 interacts. The connection adapter 30 has no external thread and its largest outer diameter is slightly smaller than the inner diameter of the sleeve-shaped securing element 50 , The skilled artisan will recognize that by the screw between fuse element 50 and contact element 40 the two forms of connection 32 and 42 be pressed against each other.

LIST OF REFERENCE NUMBERS

10

 electric wire

12

 strands

14

 Jacket (insulation)

20

 crimp barrel

30

 connection adapter

32

 compound form

34

 contact area

40

 electrical contact element

42

 complementary connection form

50

 fuse element

52

 flange

54

 thread

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 1032077 [0004]

Claims (10)

Cable connection for connecting an electrical cable ( 10 ) with an electrical contact element ( 40 ), comprising: - an electrical cable ( 10 ) with several strands ( 12 ), isolated from insulation ( 14 ) are included; A crimp barrel ( 20 ), which is pressed onto a free end of the cable around the strands ( 14 ) to compress; and - a connection adapter ( 30 ), which has a contact surface ( 34 ), which is welded to the end faces of the compressed strands; characterized in that the connection adapter ( 30 ) at the contact surface ( 34 ) opposite side via a connection form ( 32 ), which has at least one surface obliquely to the end face of the strands ( 14 ) and is designed to be connected with a complementary connection form ( 42 ) of the electrical contact element ( 40 ) to cooperate. Cable connection according to claim 1, characterized in that the connection form ( 32 ) has a conical shape. Cable connection according to claim 1 or 2, characterized in that the connection is a fuse element ( 50 ), which for secure connection of connection adapter ( 30 ) and electrical contact element ( 40 ) is trained. Cable connection according to the preceding claim, characterized in that the securing element ( 50 ) is a sleeve that the connection adapter ( 30 ) and the electrical contact element ( 40 ) at least partially. Cable connection according to one of the preceding claims, characterized in that the connection form ( 32 ) is a cone or a corresponding conical recess. Cable connection according to the preceding claim, characterized in that the connection form ( 32 ) and the complementary connection form ( 42 ) are dimensioned such that a frictional connection between them is possible. Cable connection according to the preceding claim 5 or 6, characterized in that the cone or the conical recess has an opening angle α between 60 and 130 degrees, more preferably between 60 and 110 degrees and most preferably between 70 and 100 degrees and / or the diameter d of the base of the cone is 0.7 to 1.3 times the diameter of the cable, more preferably 0.8 to 1.2 times, and most preferably 0.9 to 1.1 times is. Cable connection according to one of the preceding claims, characterized in that the complementary connection form ( 42 ) of the electrical contact element ( 40 ) is set up such that it can be prestressed in the connecting direction by means of a spring element. A method of making a connection of an electrical cable to an electrical contact element, comprising: - providing an electrical cable with a plurality of strands, which are covered by an insulation; - Pressing a crimp on a free end of the cable; Providing a connection adapter which has a contact surface and which on the side opposite the contact surface has a connection form which has at least one surface which is oriented obliquely to the end side of the strands and is preferably conically shaped, - Welding of the connection adapter via the contact surface with the end faces of the strands; and then - Providing an electrical contact element with a complementary shape to the conical connection form connection form and joining of connection adapter and contact element by means of the connection forms. Method according to one of the preceding method claims, characterized in that the welding takes place via friction welding.

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