阅读说明：本技术 建立屏蔽电缆屏蔽连接的方法和装置；具有屏蔽件的电缆 (A method and apparatus for establishing a shielded connection of a shielded cable; cable with shield ) 是由 奥利弗·沙尔科夫斯基 于 2018-08-15 设计创作，主要内容包括：本申请涉及用于形成经屏蔽的电缆(1,2,4,5)的屏蔽连接的方法,该方法包括如下步骤：将套管(3)推到电缆(1,2,4,5)的屏蔽件(4)上；将电缆连同套管(3)引入电磁脉冲焊接线圈(6)中；以及用脉冲对电磁脉冲焊接线圈(6)通电,使得将套管(3)材料配合地接合到屏蔽件(4)上。(The application relates to a method for forming a shielded connection of a shielded electrical cable (1,2,4,5), comprising the steps of: pushing the sleeve (3) onto the shield (4) of the cable (1,2,4, 5); the cable together with the sleeve (3) is led into an electromagnetic pulse welding coil (6); and energizing the electromagnetic pulse welding coil (6) with a pulse so that the sleeve (3) is materially joined to the shield (4).)

1. Method for forming a shielded connection of a shielded electrical cable, the method comprising the steps of:

-pushing the sleeve onto the shield of the cable;

-introducing the cable together with the bushing into an electromagnetic pulse welding coil;

and energizing the electromagnetic pulse welding coil with a pulse such that the sleeve is materially bonded to the shield.

2. The method of claim 1, wherein the first and second light sources are selected from the group consisting of,

it is characterized in that the preparation method is characterized in that,

-removing the outer insulation of the cable in an area and pushing the sleeve onto said area.

3. The method according to any one of the preceding claims,

it is characterized in that the preparation method is characterized in that,

-the duration of the pulse is less than 1 second.

4. The method according to any one of the preceding claims,

it is characterized in that the preparation method is characterized in that,

the pulses have a current intensity of at least 10kA, preferably at least 100 kA.

5. The method according to any one of the preceding claims,

it is characterized in that the preparation method is characterized in that,

the electromagnetic pulse welding coil is preferably a ring coil, and the cable together with the sleeve is introduced into the electromagnetic pulse welding coil concentrically to the coil axis of the ring coil.

6. The method according to any one of the preceding claims,

it is characterized in that the preparation method is characterized in that,

the sleeve is cold deformed by pulsing.

7. The method according to any one of the preceding claims,

it is characterized in that the preparation method is characterized in that,

-removing the outer insulation of the cable at one end face end of the cable.

8. An electromagnetic pulse welding device having

-an electromagnetic pulse welding coil,

-a pulse generator for generating a pulse of the electrical energy,

the method is characterized in that the cable sleeved with the sleeve is introduced into the electromagnetic pulse welding coil through a feeding device.

9. An electric cable having

-an inner conductor which is,

-an inner insulator surrounding the inner conductor,

-a shield surrounding the inner insulator,

-an outer insulator surrounding the shield,

a bushing pushed onto the area where the outer insulator is removed and surrounding the shield,

the electromagnetic pulse welding method is characterized in that the shielding piece and the sleeve are welded in a material matching mode through electromagnetic pulse welding.

10. The electrical cable as set forth in claim 9,

it is characterized in that the preparation method is characterized in that,

the sleeve and the shield are made of the same metal, in particular of aluminum or an alloy thereof or copper or an alloy thereof.

11. The cable according to claim 9 or 10,

it is characterized in that the preparation method is characterized in that,

the inner conductor has a circular or rectangular cross section.

12. Cable according to any one of the preceding claims,

it is characterized in that the preparation method is characterized in that,

the shield is formed by a metal fabric and/or a metal foil.

13. Cable according to any one of the preceding claims,

it is characterized in that the preparation method is characterized in that,

the sleeve has an open cross section and an outer cross section, the open cross section being different from the outer cross section.

Technical Field

The invention relates to a method for producing a shielded connection of a shielded cable, to a device for carrying out the method, and to a cable produced by the method.

Background

Due to the increasing share of hybrid and electric vehicles and the resulting electrification of drive-train systems, the demand for so-called high-voltage lines is growing. A high-voltage wire is a wire with a large cable cross-section with a current-carrying capacity of several hundred amperes and a dielectric strength of several hundred volts to several thousand volts. The electromagnetic flow of the wire is an essential component due to the high voltage and high current in the high voltage wire. The electromagnetic compatibility of the current carrying wires in high voltage applications must be ensured and the influence on other electrical components must be reliably avoided.

The electromagnetic radiation is shielded by a shield surrounding the cable conductor. Here, the shield must be connected to the same potential, in particular to ground, completely along the current-carrying component to ensure reliable shielding against electromagnetic radiation. However, this also means that the shield must be intact not only along the cable harness, but also at the transition between two cables and when introducing the cables into the housing, etc. Such cable leadthroughs must ensure reliable shielding contact. Since the shield is usually made of foil and/or braid, the connection to other shields is complicated from a process-technical point of view. For this reason, it has been proposed to contact the shield with a bushing, which is then used as a shield contact.

Various techniques are known for contacting the bushing with the shield, as described, for example, in DE 102007051836 a1 or DE 10200260897B 4. However, the connection method described therein involves complicated manufacturing work. The known methods are generally based on form-fitting and/or force-fitting, wherein the long-term stability of these connections is questionable. Especially in automotive applications where the joint is exposed to extreme environmental conditions, especially mechanical vibrations and electrochemical corrosion of the electrolyte, it is therefore necessary to maintain a stable contact between the shield and the bushing for a long period of time.

Disclosure of Invention

It is therefore an object of the present invention to provide a shielded connection which is stable over time and can be produced in a reliable manner, in particular while maintaining a short cycle time during production.

This object is solved by a method according to claim 1, a device according to claim 8 and a cable according to claim 9.

In the method of the invention, the sleeve is pushed onto the shield of the cable.

A cable is generally composed of an inner conductor, also called core, an inner insulator, a shield and an outer insulator. Here, the inner conductor may be a flat conductor or a circular conductor, and may be composed of an integral solid material or composed of a stranded wire. The inner insulator insulates the inner conductor from the shield.

The shield is exposed and the sleeve is pushed directly onto the shield. The sleeve can be one-piece or multi-piece here and can in particular have an upper part and a lower part. The sleeve may be placed or sheathed to the cable or shield.

After the sleeve is sleeved/placed on the shield, the sleeve is temporarily fixed to the shield, e.g. by holding arms or the like. The fixation may also be ensured by a press fit over the sleeve to the shield. The inner insulator is in particular elastically deformable and thus allows the sleeve to be pushed over while the insulator is deformed, so that the sleeve is held firmly on the shield by the restoring force of the insulator.

In order to easily push the sleeve onto the shield, the sleeve may have an opening widening towards the end face end of the sleeve. This allows the sleeve to be pushed with the widened end onto the shield and, during the pushing, the sleeve presses the shield against the insulator, thereby being held firmly on the shield.

The cable and the bushing are then introduced together into the electromagnetic pulse welding coil using a corresponding tool.

Once the cable and sleeve are positioned in the electromagnetic pulse welding coil, a pulse of current is applied to the electromagnetic pulse welding coil. The pulses have such a current strength that the lorentz forces acting on the bushing due to eddy currents induced in the bushing are sufficient to plastically deform the bushing and in particular to materially engage it to the shield.

With the high deformation speed caused by the very short pulses, cold welding can occur between the material of the shield and the material of the sleeve. The inner wall of the sleeve is in particular connected in a material-locking manner to the shield.

The longitudinal cross section of the joint area between the sleeve and the shield shows in particular a wavy welding pattern. A metal-to-metal contact area is created between the metal sleeve and the metal of the shield.

In order to push the sleeve onto the shield, it is proposed to first remove the outer insulation of the cable in one area and then push the sleeve onto this area. Removing the insulator exposes the shield so that the ferrule can be placed directly over the shield. If the region from which the insulation is removed is located between the two end-face ends of the cable and is surrounded on both sides by an outer insulation, the bushing is preferably multi-part and can be placed radially from the outside onto the shield. The individual parts of the sleeve can be locked together by a corresponding mechanical design, so that the parts of the sleeve are arranged firmly on the shield before the sleeve is brought into material-locking engagement with the shield.

The duration of the pulse energizing the electromagnetic pulse welding coil is less than 1 second, particularly less than 0.5 second, and preferably about 0.3 second or less. The duration of the pulse here is preferably at least longer than 0.1 seconds.

For short pulse durations, the energy store in the pulse generator will discharge very quickly. This results in a high current intensity, since the charge stored by the energy store flows through the electromagnetic pulse welding coil in a very short time. In particular, it is proposed that the pulses have a current intensity of at least 10kA, preferably at least 100 kA. For this purpose, at least one capacitor is preferably arranged in the pulse generator, the charge of which discharges in a pulse-like manner. The voltage may be, for example, 400V.

The high current intensity in the electromagnetic pulse welded coil results in large eddy currents in the sleeve, which in turn causes lorentz forces acting on the sleeve directed towards the inside of the coil. The lorentz force causes a permanent plastic deformation of the sleeve in a short time, thereby ensuring a cold weld between the sleeve and the shield.

The electromagnetic pulse welding coil is preferably a toroidal coil. In order to ensure that the sleeve is welded to the shield in the circumferential direction with approximately the same energy, it is proposed that the cable together with the sleeve is introduced into the electromagnetic pulse welding coil concentrically to the coil axis of the annular coil. This results in the lorentz forces being distributed as evenly as possible along the circumference of the casing. This ensures that the plastic deformation of the sleeve is as uniform as possible and thus that the material-fitting engagement of the sleeve on the shield along the circumference of the inner surface of the sleeve is as uniform as possible.

As already explained, the sleeve is cold-deformed by means of pulses. By means of rapid cold forming, only very low temperatures are produced in the welding zone, which can be advantageous. By means of the pulses and the resulting lorentz forces, the yield stress of the casing material is exceeded. The sleeve is thus cold formed without contact. A high-speed collision occurs between the inner surface of the sleeve and the shield, so that a material-fit connection between the sleeve and the shield is achieved almost without heating.

Preferably, the outer insulation of the cable is removed at one end face end of the cable, from which end face end the sleeve is then pushed onto the cable or shield.

Another aspect is an electromagnetic pulse welding apparatus having an electromagnetic pulse welding coil and a pulse generator. The jacketed cable is introduced into the electromagnetic pulse welding coil by a feeding device. Here, the electromagnetic pulse welding coil is preferably a ring coil, and the feeding device is designed such that the sheathed cable is arranged at the center of the electromagnetic pulse welding coil. Preferably, the longitudinal axis of the cable is collinear with the longitudinal axis of the electromagnetic pulse welding coil. This results in an even pressure distribution on the sleeve during welding. So that no tilting moment acts on the cable.

Another aspect is a cable having an inner conductor, an inner insulator surrounding the inner conductor, a shield surrounding the inner insulator, an outer insulator surrounding the shield, and a sleeve pushed over the area where the outer insulator is removed and surrounding the shield. The cable is characterized in that the shield connection is ensured in such a way that the shield and the sleeve are welded in a material-fit manner by electromagnetic pulse welding.

The connection between the sleeve and the shield is particularly good when the sleeve and the shield are made of the same metal. Non-ferrous metals, such as aluminum or copper and their corresponding alloys, are particularly suitable. It is important that the material of the bushing has to have a high electrical conductivity. In this way, large eddy currents are generated in the casing, which results in large lorentz forces acting on the casing.

The inner conductor preferably has a circular or rectangular cross section and thus a circular cable or a flat cable can be formed. The inner conductor is formed in particular as a stranded conductor or as a one-piece conductor.

The shield is preferably a metal fabric and/or a metal foil.

In order to adapt the sleeve to the cable lead-in, it is proposed that the sleeve has an outer circumference which is adapted to the cable lead-in. This may result in the sleeve having an open cross-section and an outer cross-section, the open cross-section being different from the outer cross-section. The opening cross-section corresponds approximately to the cross-section of the inner conductor, the inner insulator and the shield. This makes it possible to push the sleeve onto the shield with an open cross section. An outer cross section different from the cross section of the opening ensures that the sleeve corresponds to the cable lead-in after the material-fit engagement and ensures a good shielding connection.

Drawings

Hereinafter, the present invention is explained in more detail by the drawings showing the embodiments. In the figure:

figure 1 shows a cable with a bushing,

FIG. 2 shows a cable introduced into an electromagnetic pulse coil;

fig. 3 shows a bushing welded to a shield by means of electromagnetic pulses.

Detailed Description

Fig. 1 shows a cable with an inner conductor 1. The inner conductor 1 may be a stranded wire or formed of a solid material. The inner conductor 1 is preferably made of copper or an alloy thereof, but may also be made of aluminum or an alloy thereof. The cross section of the inner conductor 1 is preferably circular or rectangular.

Around the inner conductor 1, a primary insulator 2 is provided. The primary insulator 2 is made of an electrically insulating material.

The shield 4 is wound around the primary insulator 2. The shield 4 may be formed as a metal foil or a metal fabric or a combination of both.

A secondary insulator 5 surrounds the shield 4. The secondary insulator 5 may be made of the same material as the primary insulator 2.

It can be seen that at the end face end of the cable, the secondary insulation 5 has removed the shield 4. The shield 4 is exposed in the region of the end face. The sleeve 3 can be pushed onto this area. The bushing 3 preferably has an inner diameter which, together with the shield 4, corresponds to the outer diameter of the primary insulator 2.

The sleeve 3 is preferably made of the same material as the shield 4. In particular copper or aluminium and alloys thereof are suitable.

After pushing the sleeve 3 onto the shield 4, the cable is positioned in the electromagnetic pulse coil 6 by the feeding means, as shown in fig. 2. The electromagnetic pulse coil 6 has a plurality of windings and is formed in particular as a toroidal coil. The winding circumferentially surrounds the cable. The cable is preferably collinear with its longitudinal axis with the longitudinal axis of the electromagnetic pulse coil 6.

It can be seen that the cable with the bushing 3 is located inside the electromagnetic pulse coil 6.

The short current pulses can be transmitted to the electromagnetic pulse coil 6 by means of a pulse generator, which has in particular at least one capacitor and an ohmic resistor and a switch. For this purpose, the electromagnetic pulse coil 6 is short-circuited by a capacitor and a resistor. The capacitor is thereby discharged and the stored charge flows very rapidly through the electromagnetic pulse coil 6. Here currents of up to several hundred kA are generated.

The current flowing in the coil 6 generates eddy currents in the sleeve 6. As a result, lorentz forces are exerted on the sleeve 3, which lorentz forces act in the cable interior direction.

As shown in fig. 3, the sleeve 3 is cold-deformed by the lorentz force. A lorentz force acts on the sleeve 3 in the direction 7 and the sleeve 3 is plastically deformed and pressed against the shield 4 within fractions of a second. A metal-to-metal connection is formed between the inner wall of the sleeve 3 and the shield 4 by high accelerations. The sleeve 3 is thereby not only positively and non-positively connected to the shield 4, but is also joined together by a material fit.

The cable is then removed from the electromagnetic pulse coil 6 and the next cable can be introduced.

The cycle time is very short, since the welding is performed in a very short time, in particular less than 1 second. The pulse generator can be charged while removing the cable from the electromagnetic pulse coil 6 and introducing a new cable. The duration may be sufficient to charge the pulse generator or its capacitor with sufficient charge so that sufficient lorentz force acts again on the bushing 3 in the next operating step.

By means of the method and the device shown, a long-term stable connection between the sleeve and the shield can be established in a process-safe manner.