Method for producing an electrical line, electrical line, and vehicle on-board power supply system having a corresponding electrical line

Abstract

A cable has a wire bundle composed of a number of individual wires and an insulating sheath. The wire bundle is guided along a longitudinal center axis by a shaping element in order to guide and to specify the cross-sectional shape of the wire bundle in a feeding region immediately upstream of an extruder. The shaping element rotates about the longitudinal center axis, and the insulating sheath is subsequently applied to the wire bundle by the extruder.

Claims

1. A method for producing an electrical line having at least one conductor with a wire bundle made up of a plurality of single wires, and an insulating sheath surrounding the wire bundle, which comprises the step of: guiding the wire bundle through a shaping element along a center longitudinal axis in a feeding area immediately upstream of an extruder for specifying a cross-sectional shape of the wire bundle, wherein the shaping element rotates about the center longitudinal axis and relative to and around the wire bundle, and that thereafter, the insulating sheath is applied to the wire bundle by means of the extruder; wherein as the wire bundle is guided through the shaping element in the guiding step, the shaping element brings the wire bundle into a desired circular cross sectional shape; and wherein the shaping element is a shaping sleeve.

2. The method according to claim 1, wherein the wire bundle has a lay length greater than 0.5 m.

3. The method according to claim 1, which further comprises positioning the shaping element at a distance of less than 2 m from the extruder.

4. The method according to claim 1, which further comprises positioning the shaping element at a distance of less than 0.5 m from the extruder.

5. The method according to claim 1, which further comprises compressing the wire bundle with the shaping sleeve.

6. The method according to claim 1, wherein a diameter of the wire bundle is reduced by at least 3%.

7. The method according to claim 1, which further comprises rotating the shaping element at a speed of at least 500 rpm.

8. The method according to claim 1, wherein the single wires in the wire bundle are untwisted or the wire bundle is formed with a lay length down greater than 2 m.

9. The method according to claim 1, wherein the single wires in the wire bundle are untwisted.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

(1) FIG. 1 is a diagrammatic, cross-sectional depiction of a single-conductor line;

(2) FIG. 2 is a longitudinal-sectional depiction taken along the line II-II shown in FIG. 1;

(3) FIG. 3 is a top view of a production facility for the line; and

(4) FIG. 4 is a longitudinal-sectional depiction of an alternative embodiment of the single-conductor line.

DETAILED DESCRIPTION OF THE INVENTION

(5) Corresponding parts are provided with the same reference numerals in each case in all figures.

(6) Referring now to the figures of the drawings in detail and first, particularly to FIG. 1 thereof, there is shown a single-conductor line 2 which is not depicted true to scale, is formed by a conductor 4.

(7) The conductor 4 contains a wire bundle 6 which is enclosed by an insulating sheath 8 made of plastic. Each wire bundle 6 in the exemplary embodiment is made up of seven single wires 10 having a diameter d1<1 mm, wherein six single wires 10 rest circumferentially against a central single wire 10.

(8) As depicted in FIG. 1, the wire bundle 6 is configured as a compressed wire bundle 6, and the single wires 10 are accordingly pressed together. As a result, the thickness of any wire bundle 6 or the diameter of any wire bundle 6 is reduced, and the cross sectional shape of any single wire 10 deviates from a round shape due to the deformation which any single wire 10 experiences in the course of compression of the wire bundle 6. The overall diameter d2 of the wire bundle 6 is, for example, in the range from 2 to 3 mm.

(9) Due to this compression, the two wire bundles 6 each partially retain their shape even without the insulating sheath 8. Due to the compression, the cohesion between the single wires 10 is typically not so strongly pronounced as in the case of a conventional stranded wire, in which the shape of the stranded wire is permanent, in particular due to the directed twisting of the single wires 10. Such directed twisting is not provided in the wire bundles 6, as is schematically depicted in FIG. 2. The single wires 10 therefore run at least essentially in parallel with each other and with a center longitudinal axis. Thus, they are untwisted.

(10) In this case, the production of a corresponding cable 2 takes place in a production facility 12 as depicted in a manner not true to scale in FIG. 3. Here, the prefabricated single wires 10 are unwound from a wire reel 14, for example, in the form of a loose wire bundle 6, and continuously fed to an extruder 16, in which they are provided with the insulating sheath 8. Immediately ahead of the extruder 16, i.e., in a feed area seen in the processing direction A ahead of the extruder entrance, the single wires 10 are guided through a compressing unit, i.e., a shaping sleeve 18, with the aid of which the single wires 10 are bundled and deformed into a compressed wire bundle 6. An output of the shaping sleeve 18 is spaced away from an input of the extruder by a distance a. The distance a is preferably a maximum of a few meters, in particular less than 2 m, preferably approximately 0.5 m.

(11) The processing speed, i.e., the speed at which the wire bundle 6 is drawn through the shaping sleeve 18, is typically 1000 to 2000 m/min.

(12) In order to laterally deflect the forces occurring during compression and thus to reduce the risk of a wire break, the shaping sleeve 18 rotates at the same time about the center longitudinal axis 20 of the wire bundle 6. Preferably, it rotates at a speed of greater than 500 rpm, in particular approximately 1000 rpm.

(13) In the extruder 16, the sheath 8 is subsequently extruded onto the wire bundle.

(14) Instead of the shaping sleeve 18 described here, other compression units may also generally be used, as are used, for example, for rotary swaging of bundles. Here, multiple movable shaping jaws are arranged distributed around the circumference of the wire bundle 6, which compress the wire bundle 6 via coordinated movement sequences. However, this rotary swaging is generally used for significantly larger cross sections.

(15) Furthermore, it is to be noted that the single wires 10 of the bundle 6 are hard-drawn and should not be soft annealed. In fact, analyses have shown that only hard-drawn wires may be compressed to the desired degree. Annealed wire material actually flows preferably only in the axial direction, without the desired compression, i.e., deformation in the radial direction of the single wires 10, taking place.

(16) During the production of the cable 2, if the bundle 6 is not unwound from a wire reel 14 which is also rotating, but rather from a stationary wire reel 14, this typically results in bunching of the single wires 10 in the wire bundle 6 which is related to the unwinding process, which is not produced in a directed manner, having a lay length s of, for example, 2 m, as depicted in FIG. 4. Here, the lay length s denotes the length in which the wire bundle rotates once by 360 about its own center longitudinal axis. In this case, the lay length s of the unwinding process-related twisting or bunching is essentially a function of the diameter of the wire reel 14, and is essentially greater than a lay length according to the related art which is produced in a directed manner.

(17) The present invention is not limited to the exemplary embodiment described above. Rather, other variants of the present invention may be derived from them by those skilled in the art, without departing from the subject matter of the present invention. In particular, furthermore, all individual features described in connection with the exemplary embodiment may also be combined with each other in a different manner without departing from the subject matter of the present invention.

(18) The following is a summary list of reference numerals and the corresponding structure used in the above description of the invention: 2 Wire/cable 4 Conductor 6 Wire bundle/bundle 8 Sheath 10 Single wire 12 Production facility 14 Wire reel 16 Extruder 18 Shaping sleeve 20 Center longitudinal axis A Processing direction a Distance d1 Diameter of single wire d2 Diameter of wire bundle s Lay length