EP3879540B1 - Method of making a fluid-tight cable, use of a solder connector therefor and a fluid-tight cable - Google Patents

Description

The present invention is based on a method for producing a liquid-tight cable, which has at least one strand provided with a sheath and made of a plurality of individual wires, with a circumferential strip being removed from the sheath at a sealing point and the individual wires of the at least one strand in the area of the A sealant flows around and penetrates the sealing point to form a liquid-tight barrier, and wherein a cap element is connected in a liquid-tight manner to produce a sealing connection with the casing at least on the one hand of the sealing point, and the use of a soldered connector to produce a liquid-tight cable and such a liquid-tight cable.

Such a method is already in the DE 11 2008 002 857 T5 described. Furthermore, on the U.S. 1,267,832 A , the DE 11 2013 006 224 T5 , the WO 2008/099 675 A1 , the U.S. 3,451,609 A and the DE 893 821 B as further prior art.

Such a method and such a cable are already in the previously known Japanese document JP 2001057252 A described. To a cable liquid tight To seal, a strip of the insulating sheath is first removed from a stranded wire and then a drop of silicone resin is applied to the exposed area. Then a heat-shrinkable tube is pulled on and fastened with hot-melt glue in between.

It aims in a similar direction CN 106 328 261 A , which also removes a strip of cladding and replaces it with a block of resin. The resin block overlaps the ends of the jacket so that it runs into the ends of the jacket while it is still liquid and seals them.

This can be according to JP 2001057252 A can also be achieved by inserting the stranded wire as a whole into an insulation displacement connector, thereby causing the sheathing to open. Resin, in turn, runs into this small cut and is cast in a block that encloses the entire insulation displacement connector.

The JP 2009152012 A finally provides for applying a hot-melt adhesive to a stripped area and applying a vacuum to the cable ends so that the melt is sucked into the cable and seals it.

These previously known solutions ultimately create sealed cables, which, however, are associated with a great deal of effort or at least with the flaw of a very space-consuming solution. In particular, after the stripping step, a barrier is first created directly on the wires of the stranded wire. This barrier is intended to create a stranded composite from the individual wires, which as such can no longer be penetrated by liquid.

The problem is particularly well known in the case of cables in vehicle construction, for example in the manufacture of cables for bicycles with an electric support motor. There, the controller is connected to the electric motor, and it is well known that watertight connectors are also used on the motor become. However, spray water can penetrate the cable sheathing in front of the connector and, due to the capillary effect, be conducted to the opposite end of the cable and land there on the control board, where contact between conductor contacts or defects due to corrosion can occur.

Since such a cable is in itself a simple, inexpensive construction, a simple and inexpensive solution is also sought for its sealing. However, in the case of the known solutions, it is felt to be disturbing that large blocks of resin are formed, which are attached to the cables. Only with the solutions JP 2007287647 A and JP 2009152012 A this is not the case. There, however, the barrier must first be applied with resin, then in the first case a hose pulled over it and in the second case a vacuum applied to the cable. In addition, the material of the barrier is not considered to be optimal, as there is no guarantee that the resin is evenly distributed in the casing.

Furthermore, it is also fundamentally known to create the tightest possible connection between stranded wire and sheathing, which leads to a very stiff cable but not to satisfactory tightness.

Against this background, the present invention is based on the object of producing a cost-effective and as quick as possible seal for a cable, which allows high tightness with the lowest possible use of material and labor.

This is achieved by a method for producing a liquid-tight cable according to the features of claim 1, and by a liquid-tight cable according to the independent claim 8. This is achieved in particular by using a soldered connector according to the features of claim 7. Useful developments of the method can dependent claims following claim 1.

According to the invention, similar to the solution from the prior art, the stranded wire is first freed from a circumferential strip of insulating sheathing in the area of a sealing point, ie the stranded wire is exposed in one strip. A barrier made of a metal liquefied under the action of heat is then applied to the stranded wire, which creates the possibility that the material of the stranded wire is well coated by the liquid metal, which can also flow between the individual wires and, if necessary, alloy with them or can flow together. The metal can preferably be liquefied and fused by welding, ultrasonic welding, resistance welding or also by soldering. In this respect, the metal used can also be an alloy or a solder, the latter in particular being provided with a flux. The possibilities of creating a lasting liquid-tight barrier in this way are significantly better than by applying a resin, which due to its surface tension has difficulty penetrating between the wires. As the metal cools, it solidifies again and thus forms the desired barrier. This will also cool much faster and harden in this way. This will also penetrate into the shroud allowing a seal to the ends of the shroud. A cover element protects the treated area and provides additional tightness and strength.

In an embodiment not belonging to the invention, the barrier can also be formed by wrapping a strip of material, preferably a metal strip, around the wires of the stranded wire, which is then joined so thickly with a joining tool that the stranded wire becomes completely liquid-tight.

In an expedient further development, the cap element can be designed as a shrink tube, which contracts due to the effect of heat over the sealing point and due to its firm attachment to the casing seal the connection. While the current flow through the cable can take place unhindered through the sealing point, the ingress of water or liquid in general, ideally even an ingress of gas, is prevented in the long term.

In addition, the shrink tube can be treated in such a way that it also lies tightly against the barrier in order to completely prevent flow within the shrink tube. This is promoted by both a slightly thicker barrier and a slightly tighter shrink tube.

It is also possible to add an adhesive to the shrink tube, which can be applied circumferentially around the inside of the tube wall in the region of the ends of the shrink tube up to the flush, better up to the overlapping sealing point. This can preferably be a hot-melt adhesive, which liquefies when exposed to heat and solidifies when it cools down. Such an adhesive ring can also be attached in the area of the barrier. For a suitable placement of the shrink tube, this can preferably be transparent, so that it can be seen through its wall whether its placement is correct. The hot glue will also liquefy when you shrink the shrink tube, since heat is also required for the shrinking process. Bonding and shrinking become a single step.

Furthermore, a ring made of solder, such as tin solder, can be assigned to the inside of the shrink tube, or in general to the cap element. This makes it possible to effect both the shrinking and gluing of the cap element and the construction of the barrier in a single work step by heating the cap element prepared in this way with a hot air gun. Simultaneously with shrinkage and bonding, the ring of solder through which the stranded wire was previously inserted and positioned will liquefy, meet the stripped point of the strand and fill it out. The heat shrink tubing will contract over the barrier and jacket, completely sealing the cable inboard and out.

As an alternative to using a shrink tube as a cap element, this can also be implemented as a preferably insulated metal sleeve, which is also placed around the sealing point and is deformed by plastic deformation until it is in liquid-tight contact with the casing and/or barrier, optionally with an interposed adhesive. In particular, deformation can take place with a joining tool. However, this configuration is not part of the invention.

Cables with several cores are often used, whereby of course each individual strand has to be sealed separately. However, since an outer sheath usually has to be removed in one area in order to remove the sheathing of the individual strands, it makes sense to pull an elastic hose, particularly preferably a neoprene hose, over the strands that have been freed from the outer sheath and sealed in this area. possibly also in turn as a heat-shrink tubing to make the cable mechanically more durable and to protect the sealed areas.

A good possibility of inexpensively using a cap element prepared as described above is the use of a readily available soldered connector, which is known for the electrical connection of cable ends. Attaching such a solder joint to a stripped location in the cable reduces the steps of liquid-tight sealing per individual strand/wire to removing a strip of insulation, covering and positioning the solder joint and heating it with a heat gun. This is both extremely material-saving and can be managed with a minimal amount of work.

The invention described above is explained in more detail below using an exemplary embodiment.

Figur 1

eine Litze, bei der ein Streifen ihrer Ummantelung im Bereich einer Dichtungsstelle entfernt wurde in einer perspektivischen Darstellung,

Figur 2

die Litze gemäß Figur 1, bei der eine metallische Barriere im Bereich der Dichtungsstelle geschaffen wurde in einer perspektivischen Darstellung, sowie

Figur 3

die Litze gemäß Figur 2, bei der ein Überwurfelement über der Dichtungsstelle positioniert wurde in einer perspektivischen Darstellung.

Show it

figure 1

a strand in which a strip of its sheathing has been removed in the area of a sealing point in a perspective view,

figure 2

the strand according to figure 1 , in which a metallic barrier was created in the area of the sealing point in a perspective view, as well as

figure 3

the strand according to figure 2 , in which a cap element was positioned over the sealing point in a perspective view.

figure 1 shows a stranded wire 1, which consists of a bundle of individual wires that are surrounded by a sheath 2. However, the sheathing 2 has been removed beforehand in a circumferential strip in the area of a sealing point 3, so that the individual wires of the stranded wire 1 are exposed. At this sealing point 3, which is located in the area of the cable end, a seal is now to be applied, which is intended to prevent moisture from penetrating into the cable, ie between the wire and the sheathing 2 and between the individual wires.

figure 2 shows a second step for this, in which a barrier 4 is first attached in the area of the sealing point 3 . In the present case, the barrier 4 is formed from a solder which has been melted under the action of heat and applied to the stripped stranded wire 1 . The solder connects to the individual wires of the stranded wire and runs due to the low surface tension, which is lowered by the flux present in the solder, such as rosin around and between the wires and wets them. At the same time, a liquid-tight barrier 4 is formed from the composite stranded wire that is produced in this way, which prevents liquid from leaking through the cable or the stranded wire 1 . Ideally, the barrier may be about the same or slightly thicker than the surrounding portions of the jacket and completely fills the recessed strip lengthwise of the cable. In contrast to the use of resins known in the prior art for forming the barrier 4, the barrier 4 according to the invention cures within a few seconds.

figure 3 finally shows how the cable is gripped by a cap element 5, which is a tubular heat-shrinkable tube and has, in the area of its ends, two rings of adhesive 6, so-called hot-melt adhesive, which is arranged on the inside of the cap element 5 and melts when exposed to heat. The cap element 5 is made of a plastic that contracts when exposed to heat, which is also transparent, so that the positioning can also be checked from the outside. If the cap element 5 is correctly positioned, i.e. with the barrier 4 between the rings of adhesive 6, it is heated using a hot air gun so that the adhesive 6 liquefies and the shrink tube is pressed tightly against the casing 2 and the barrier 4 pulls together.

In addition to the rings of adhesive 6, an additional, in particular centrally arranged ring of solder can optionally be arranged in the cap element 5, so that the steps of forming the barrier 4 and gluing with the adhesive 6, as well as pulling together the cap element 5, all of which are due to exposure to heat can be accomplished in a single operation. This saves a considerable amount of time and allows the use of inexpensive, prefabricated solder connectors in order to carry out the method according to the invention.

A method is thus described above for producing a cost-effective and as quick as possible seal for a cable, which enables high tightness with the least possible use of material and labor, as well as a corresponding cable. The use of a soldered connector as a cap element, with which several process steps can be carried out in parallel, is particularly advantageous here.

REFERENCE LIST

1

strand

2

sheathing

3

sealing point

4

barrier

5

throw element

6

adhesive

Claims (8)

1. A method for producing a liquid-tight cable which has at least one stranded wire (1) provided with a sheathing (2) and consisting of a plurality of individual wires, wherein a circumferential strip is removed from the sheathing (2) at a sealing point (3) and the individual wires of the at least one stranded wire (1) are compacted in the region of the sealing point (3) by a sealing means to form a liquid-tight barrier (4), and wherein a covering element (5) is connected in a liquid-tight manner to the sheathing (2) at least on one side of the sealing point (3) while producing a sealing connection,
   the barrier (4) being produced by applying to the at least one strand (1) in the region of the sealing point (3) a metal which is liquefied under the effect of heat and which penetrates between the individual wires and, when it cools, is solidified to form the barrier (4), characterized in that the sheathing element (4) is assigned a ring of a solder centrally on the inside, through which ring the at least one strand (1) is introduced into the sheathing element (4), which is placed over the sealing point (3) and which is heated together with the covering element (5), and rings made of an adhesive (6) which can be liquefied under the action of heat are assigned to the covering element (5) on the inside at the edges on both sides, through which rings the at least one stranded wire (1) is introduced into the covering element (4) and which rings are placed over the sheathing (2) on both sides of the sealing point (3) and are heated together with the covering element (5).
2. The method according to claim 1, characterized in that a heat-shrinkable tube is used as the covering element (5), which shrinks under the effect of heat around the area of the sealing point (3) until it comes into liquid-tight contact with the sheathing (2)
3. The method according to any of the preceding claims, characterized in that the covering element (5) is also applied to the barrier (4) in a liquid-tight manner.
4. The method according to any of the preceding claims, characterized in that an adhesive (6) which can be liquefied under the action of heat is associated with the covering element (5) on its inner side for bonding the covering element (5) to the sheathing (2) and/or the barrier (4).
5. The method according to any of the preceding claims, characterized in that a plurality of sheathed strands (1) are connected by means of an elastic hose.
6. The method according to any of the preceding claims, characterized in that the metal is fused by welding, ultrasonic welding or resistance welding, or penetrated by soldering with liquefied solder, and thereby connected to the stranded wire (1) in a liquid-tight manner.
7. A use of a soldering connector as a covering element (5) according to any of the preceding claims for the liquid-tight sealing of a cable.
8. A liquid-tight cable, which has at least one stranded wire (1) provided with a sheathing (2) and consisting of a plurality of individual wires, wherein a circumferential strip is removed from the sheathing (2) at a sealing point (3) and the at least one stranded wire (1) has a barrier (4) in the region of the sealing point (3), which is connected in a liquid-tight manner at the sealing point (3) to a covering element (5), the covering element (5) having a further liquid-tight connection to the sheathing (2) at least on one side of the sealing point (3),
   the barrier (4) being made of a metal which is liquefied under the action of heat and subsequently cooled and which forms a liquid-tight barrier (4) penetrating the individual wires, characterized in that the throw-over element (5) is arranged above the barrier (4) in such a way that the barrier (4) is located centrally on the inner side of the covering element (5) and the covering element (5) is placed on the inner side above the sheathing (2) on both sides at the edges with rings of an adhesive (6) liquefied under the effect of heat and is bonded to the sheathing (2).

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