Patent Description:
In the automotive sector, solid round conductors are often used as so-called "bus-bars", on which a connecting element is arranged. Such connecting elements are also called terminals and are used for the electrical connection of the conductor to an electrical component. To connect the round conductor to the terminal, it is regularly provided that the round conductor is flattened and fastened to the terminal with the flattened end part.

Such an arrangement, in which a round conductor with a flattened end part is attached to a terminal, can be taken from <CIT>, for example. The terminal has a shell-shaped section in which the round conductor, which may be insulated, is accommodated. The terminal also has a flat section adjoining the shell-shaped section, on which the flattened end part of the round conductor is electrically contacted. In the area of the shell-shaped section, a fastening device is provided for fastening of the round conductor. The fastening device is intended to provide a reliable, vibration-proof fastening of the round conductor to the terminal and the flattened end part is held in a defined position in relation to the flattened section of the terminal in order to form a reliable electrical contact.

<CIT> shows a terminal with a shell-shaped receptacle in which a conductor is inserted which is flattened on one side. This flattened side interacts with a welding head to produce a welded joint.

<CIT> shows a connection between two conductors with the help of an adapter part, the adapter part having a shell-shaped end for connecting with one of the conductors.

<CIT> describes a joint between a stranded copper wire and a stranded aluminium wire, wherein the end of the copper wire is shaped to form a groove into which the aluminium wire is fitted and welded to the copper wire.

<CIT> describes a crimp terminal which is connected to a stranded wire.

It is the task of the invention to provide an electrical cable with a solid round electrical conductor and a connecting element connected thereto, which is easy to manufacture.

According to the invention, a solid electrical round conductor is provided for this purpose, on which a connecting element is electrically contacted, the latter having a connecting section and a shell-shaped section with a curvature corresponding to the round conductor. A round end part of the round conductor is welded, especially ultrasonic welded, to the shell-shaped section of the connecting element. The round end part lies in the cavity formed by the shell-shaped section. The shell-shaped section has a concavely curved, in particular partially cylindrical, inner surface on its inner side, on which the end part rests. Preferably, the shell-shaped section is formed by a partial cylinder and has preferably a constant wall thickness.

It is emphasised that the round conductor is not flattened, especially in its end part. The end part of the round conductor, which has a circular cross-section, therefore lies directly in the shell-shaped section of the connecting element and is welded to it there.

This design is based on the consideration that, on the one hand, the flattening of an end part of the round conductor is associated with an additional manufacturing effort, which is therefore not necessary and also not provided for in the design according to the invention.

Furthermore, this design is based on the consideration that flattened end parts usually require additional installation space and are therefore disadvantageous in confined installation spaces. A compact design is therefore achieved with the design according to the invention.

Finally, such flattened end parts are potential points of failure.

All in all, the design according to the invention achieves a simple-to-produce and compact electrical and mechanical connection between a solid round conductor and a connecting element, which requires only little installation space and is also less susceptible to faults.

The round conductor is in particular a round conductor with an insulation sheath, the round end part of which is stripped. Alternatively, it can also be a bare round conductor. The round conductor generally has a circular cross-section over its entire length, preferably with a constant diameter over the entire length.

Solid round conductor is understood to be a solid wire or rod made of solid material.

The connecting section is arranged in particular opposite the shell-shaped section and is designed for an electrical connection to an electrical component. The connecting element is connected to the electrical component with this connecting section in the assembled state. The connecting section is designed, for example, for screw contact with a corresponding connection pole or also for a direct welded connection.

Preferably, a flexible intermediate section is arranged between the shell-shaped section and the connecting section, which is designed to enable length compensation. The flexible and in particular elastic intermediate section can therefore compensate for changes in length. This is based on the consideration that the solid round conductor has a high inherent rigidity and, for example, thermally induced changes in length can lead to a high mechanical load on a connection point between the connecting element and an electrical component connected to it. The flexible intermediate section therefore enables and compensates for a change in length directly through the connecting element itself.

Preferably, the intermediate section is undulated or corrugated so that a desired length compensation can be achieved by compressing or stretching the undulated intermediate section. In particular, the intermediate section is formed by a bent, especially by a multiple bent flat metal strip.

According to the invention the connecting element has a multilayer structure consisting of a plurality of individual layers. Preferably each layer is a metal layer.

The layers are not connected to each other at least in the intermediate section, especially in the bended sections. Therefore, the individual layers may slide to some extend relative to each other. Due to this the (bending) flexibility of the intermediate section is high.

Preferably, the individual layers are connected, especially welded to each other only in the end sections of the connection element, that means in the shell-shaped section and in the connecting section.

Preferably, the connecting section is formed as a flat metal strip. This allows easy electrical contact with the electrical component, especially in the case of a welded connection.

Preferably, the connecting element is attached with the connecting section to the electrical component by welding. Especially in such an arrangement, the flexible intermediate section is of particular importance in order to minimise the load on the two welding positions, once towards the round conductor and once towards the electrical component.

The electrical component is in particular a plug which has a connection piece. The connecting section is attached to the connection piece, in particular by welding. The connection piece of the plug is in particular a flat, in particular strip-shaped metal part on which the preferably also flat connecting section of the connecting element rests. In particular, the connection piece protrudes from a housing of the plug. A pre-assembled cable is therefore provided, which can be connected to a further electrical component by a simple plug-in connection. The further electrical component is, for example, an electrical consumer, such as an electric motor, an inverter etc..

Preferably, the connecting element is both electrically contacted and mechanically connected to the round conductor exclusively by welding. Therefore, no additional measures are provided, for example for mechanical fastening. The effort for establishing the contact connection between the round conductor and the connecting element is therefore low.

The round conductor is in particular an inherently rigid round metal conductor with a diameter of at least <NUM> and preferably of at least <NUM>.

In a preferred embodiment, the line only extends in a straight line and has no bends.

In general, the round conductor and the connection element are made of metal. Preferably, the round conductor is an aluminium round conductor. It is therefore made of aluminium or an aluminium alloy typically with an aluminium content of more than <NUM> %.

In contrast, the connecting element is preferably made of copper or a copper alloy.

Preferably a connecting element is attached to each of the round end parts of the round conductor, as described above.

The line is preferably mounted in a motor vehicle when assembled.

The round conductor is used in particular as a so-called busbar, especially in a motor vehicle electrical system. The cable preferably forms a main supply line and thus a so-called backbone or is part of such a backbone. Such a backbone typically connects a front vehicle part with a rear vehicle part for power supply. The round conductor, and thus also the cable, typically has a length of at least <NUM> and preferably of at least <NUM> or also of at least <NUM>.

In particular, the cable is a single-core cable with only one solid round conductor.

The pre-assembled cable is preferably formed by the round conductor with the connecting element connected at least at one end. Preferably, connecting elements are attached on both sides.

Preferably, the pre-assembled cable has additionally at one end and in particular at both ends an electrical component, in particular a plug, which is connected to the respective connecting element.

An embodiment of the invention is explained in more detail below with reference to the figures. These show:.

A pre-assembled electrical cable <NUM> according to <FIG> has, in the embodiment shown, a solid round conductor <NUM> which is surrounded by an insulation sheath <NUM>. A plug <NUM> is attached to each end of the round conductor <NUM> as an electrical component. The round conductor <NUM> has a blank end part <NUM> at each of its two opposite ends, which has a round cross-section. The cross-section of the round conductor <NUM> is preferably constant over its entire length. The round conductor <NUM> is therefore undeformed at the end parts <NUM>.

The round conductor <NUM> and thus also the pre-assembled cable <NUM> extend generally in longitudinal direction L from the right end to the left end.

The connection between the round conductor <NUM> and the respective plug <NUM> is made via a connecting element <NUM>, which, viewed in the longitudinal direction L, first has a shell-shaped section <NUM>, followed by a flexible intermediate section <NUM> and then a connecting section <NUM>.

The connecting element <NUM> is in particular a metallic one-piece element and in one embodiment a monolithic component. In a preferred embodiment the connecting element <NUM> is a (flexible) multilayer construction with a plurality (><NUM>, especially ><NUM>) of thin metal layers <NUM>. The layers <NUM> are only illustrated in a very simplified way in <FIG> and only in the intermediate section <NUM>. The layers <NUM> are welded together especially (only) at the end sides. Therefore, in a preferred embodiment, in the intermediate section <NUM> the layers <NUM> are not fixed to each other, for example they are not welded together. Therefore, the individual layers <NUM> can slide to some extent relative to each other. Due to this the flexibility of the intermediate section <NUM> is high.

The connecting element <NUM> is therefore in particular a metal bent part, which is preferably produced by forming from a flat metal strip. This generally has two opposite flat sides which are connected to each other via two opposite narrow sides.

To form the shell-shaped section <NUM>, one end of the flat metal strip is preferably bent around a bending axis oriented parallel to the longitudinal direction L.

The shell-shaped section <NUM> extends in the circumferential direction, for example, over an angular range of less than <NUM>° and in particular also of less than <NUM>° or less than <NUM>°. For example, the shell-shaped section <NUM> extends over an angular range of <NUM>° to <NUM>°. The shell-shaped section <NUM> preferably has a radius of curvature which is adapted to the radius of the round conductor <NUM>, so that the outer side of the round conductor <NUM>, which is freed from the insulation sheath <NUM>, lies with its cylindrical surface on an inner side of the shell-shaped section <NUM>. This inner side forms a partially cylindrical surface. In particular, the radius of curvature corresponds to the radius of the round conductor <NUM>.

The shell-shaped section <NUM> extends in the longitudinal direction L over a comparatively short length, which in the embodiment example is for example shorter than a diameter of the round conductor <NUM>.

The curved, shell-shaped section <NUM> merges into the intermediate section <NUM>, which is formed by a section of the flat metal strip, wherein said section is bent. The intermediate section <NUM>, and thus the metal strip, are formed as a whole in a curved shape and therefore are undulated. The intermediate section <NUM> has at least one arc section <NUM> and preferably a plurality of arc sections <NUM>. In particular, two or three arc sections are formed. The intermediate section <NUM> is flexible in the longitudinal direction and is specifically elastic. The flexible intermediate section <NUM> can therefore be compressed or stretched and thus serves to compensate for length. A respective arc section <NUM> is bent around a bending axis which is oriented perpendicular to the longitudinal direction L and parallel to the flat sides of the flat metal strip.

The intermediate section <NUM> finally merges into the connecting section <NUM>, which extends in particular in a straight line and in particular in the longitudinal direction L.

The connecting section <NUM> is electrically and mechanically connected to a respective plug <NUM> via a welded connection. For this purpose, a respective plug <NUM> preferably has a connection piece <NUM>, which in turn is designed in particular as a flat metal strip.

The respective plug <NUM> generally has an insulating housing in which a contact terminal not shown in more detail here is arranged, for example a socket or a plug pin, this contact terminal being electrically contacted on the connection piece <NUM>. The connection piece <NUM> emerges from the housing and is connected to the connecting element <NUM> at its emerging part.

For electrical contacting as well as for mechanical fastening between the round conductor <NUM> and the shell-shaped section <NUM>, the blank, round end part <NUM> is inserted into the shell-shaped section <NUM> and joined to it by welding.

Due to the electrical and mechanical connection of the undeformed circular end part <NUM>, the particular advantage is achieved that additional machining and treatment of the end part <NUM>, in particular flattening, is not necessary and is not carried out.

Claim 1:
Electrical cable (<NUM>), in particular for a motor vehicle, having a solid electrical round conductor (<NUM>) and a connecting element (<NUM>) which is connected to the round conductor (<NUM>) and which has a connecting section (<NUM>) for electrical connection to an electrical component (<NUM>), wherein the connecting element (<NUM>) furthermore has a shell-shaped section (<NUM>), wherein a round end part (<NUM>) of the round conductor (<NUM>) is welded to the shell-shaped section (<NUM>) of the connecting element (<NUM>), characterised in that a flexible intermediate section (<NUM>) for length compensation is arranged between the shell-shaped section (<NUM>) and the connecting section (<NUM>) and that the connecting element (<NUM>) has a multilayer structure with a plurality of layers, wherein the layers are not fixed to each other within the intermediate section (<NUM>).