EP3579344A1 - Method for overmoulding of cable shoes with complex geometries - Google Patents

Abstract

A method for the production of cable lugs (1) with overmolding (6) and a cable lug (1) with overmolding (6) are shown. According to the invention, it is provided that a soft plastic is overmolded and the method of producing the overmolded cable lug (1) comprises the following steps: a. Encapsulating the cable lug (1), and b. Bending the molded cable lug (1).

Description

FIELD OF THE INVENTION

The invention relates to a method for producing cable lugs with encapsulation and a cable lug with encapsulation.

In general, cable lugs are devices that allow electrical connection of cables or strands by screwing or plugging. In this case, the cable lug has at one end a region for fixing a cable and at the other end it comprises a contact point. Normally, a distinction is made in the cable shoes for pressing and those for crimping. To insulate the cable lug, it can be overmolded between its two ends.

STATE OF THE ART

Conventional cable lugs, which are used in areas where corrosion or contact protection or water resistance is necessary, can currently be produced by different methods.

One possibility is to first bend a finished shaped cable lug into the required geometry. At this step, the encapsulation of the previously bent cable lug takes place. In this process, a hard plastic is used for the extrusion coating.

A disadvantage of this manufacturing method is that the cable lug is first bent and then overmolded, so there may be deviations from the predetermined tolerances due to bending and extrusion coating, but this can not be compensated afterwards by bending. In addition, a bending of the cable lug by more than 90 ° after the encapsulation is not possible because of the nature of the material, since there is a material overstretching due to the forces acting on the hard plastic forces, causing the hard plastic ruptures or breaks.

The encapsulation of the cable lug is usually produced using an injection molding process.

Another possibility for producing cable lugs with corrosion or contact protection or water resistance is by using a heat-shrinkable tube.

In this case, the shrink tube is pulled over the cable lug and heated, causing the material of the hose, contracts and thus completely adjoining the cable lug.

When using this method, the cable lug should be as straight as possible, since in a strong bend of the cable lug of the shrink tube there is often no longer located directly on the lug fitting, creating cavities.

There is thus little possibility with these methods to produce cable lugs with encapsulation or sheathing with complex geometry or an angle between 0 ° and 90 ° or greater than 90 ° without cavities. Likewise, it is not possible in the currently known method to bend the cable lug only after the encapsulation, since either cavities arise or the hard plastic used would tear, whereby sufficient contact or corrosion protection or water resistance is not achieved.

OBJECT OF THE INVENTION

It is an object of the present invention to provide a method of making over-molded lobes and an overmolded lug which overcomes the above problems. In particular, the production of the cable lug should make it possible to manufacture a contact and corrosion protection and to provide water resistance, wherein the resulting from the process cable lug with overmolding can also be formed in complex geometries.

PRESENTATION OF THE INVENTION

1. a. Umspritzen des Kabelschuhs, und
2. b. Biegen des umspritzten Kabelschuhs.

The object is achieved by a method for producing cable lugs with encapsulation, wherein it is provided that is overmolded with a soft plastic and the method of manufacturing the overmolded lug comprises the following steps:

1. a. Encapsulating the cable lug, and
2. b. Bending the molded cable lug.

In addition to the process for the production of cable lugs with encapsulation, the object of the invention is also achieved by a cable lug with an overmolding of soft plastic.

The advantages resulting from the use of this method are that it is possible for the user to first encapsulate a lug with a soft plastic and only then to bring by bending in the desired geometry. It is thus facilitated by the invention to achieve the exact desired geometry of the cable lug, since the encapsulation does not take place until after bending.

In particular, with this method it is also possible to realize complex geometries of the cable lug.

The fact that the cable lug is molded around before bending, the user is given the opportunity to form cable lugs according to the respective design requirements.

A cable lug according to the invention is usually made of a conductive material, in particular a metal.

An encapsulation of the cable lug can basically be done with all types of plastic. According to the invention, it is provided that the encapsulation takes place with a soft plastic. Soft plastic or soft plastic refers to plastics with particular flexibility, i. Elastomers such as EPDM, silicone or thermoplastic elastomers.

The use of soft plastic makes it possible, on the one hand, to reverse the method steps compared with the prior art, so that initially a molding of the cable lug with a soft plastic can take place, and only thereafter the bending of the over-molded cable lug. In contrast to soft plastic, a hard plastic can no longer be bent after encapsulation because it would tear because of its material properties.

On the other hand, the use of a soft plastic for the encapsulation of the cable lug makes it possible to realize bending angles of -90 ° to 90 ° and over 90 °, since a soft plastic is more elastic and tear-resistant than a hard plastic because of its material properties. When bending over 90 °, the encapsulation of the cable lug is still arranged directly on the cable lug, thereby ensuring that contact or corrosion protection and water resistance are still maintained.

It goes without saying that all other angles and complex geometries besides - or + 90 ° or over 90 ° can be achieved by bending the cable lug.

In one embodiment of the invention, the encapsulation of the cable lug takes place by injection molding.

The injection molding process enables a rapid, cost-effective and numerous production of the cable lugs with encapsulation.

The method according to the invention makes it easier to comply with the tolerance ranges relating to the bending angle. By reversing the two process steps, namely that is first encapsulated and then bent, the complete diameter of the cable lug with encapsulation already exists during bending of the cable lug, so that the bending takes place together with it, whereby the compliance of the bending angle is facilitated because deviations can be taken into account in the thickness or other parameters in the process of extrusion coating during the bending process.

According to the invention, an adhesive / primer is applied to the cable lug or the surface of the cable lug is treated with plasma in one embodiment before the extrusion in step a.

Using an adhesive / primer or pretreatment with plasma has the advantage that the soft plastic used to encapsulate the cable lug better adheres to the metal of the cable lug and thus guarantees better contact or corrosion protection or water resistance.

In a preferred embodiment of the invention, the soft plastic is a thermoplastic. Thermoplastic plastics have the property that they can be deformed arbitrarily within a certain temperature range. Advantageous in contrast to the thermosets in the process that this process is reversible. This means that, when reheated, the shape of the thermoplastic again is arbitrarily changeable and the encapsulation of defective cable lugs could either be reused or otherwise used, whereby this method is economically and ecologically advantageous.

In order to achieve special tensile strength of the encapsulation of the cable lug, according to the invention it is provided in one embodiment that the soft plastic is an elastomer.

According to the invention, it is provided in a preferred embodiment that the soft plastic is a thermoplastic elastomer, in particular for applications up to 100 ° C.

The advantage of the thermoplastic elastomer is that it also has elastic properties in addition to its thermoplastic properties. This means that the elastomer undergoes deformation under tensile or compressive loading, but returns to its original undeformed shape when the load is released. This property is advantageous according to the invention, since a tear-resistant elastomer allows bending into complex geometries.

In one embodiment, it is provided that the soft plastic is an EPDM (ethylene-propylene-diene rubber), in particular for applications up to 150 ° C. The advantage of this synthetic rubber compound is that it has high thermal resistance. In addition, EPDM is highly elastic and tear-resistant, which is particularly advantageous for cable lugs, which have a bending angle of over 90 ° and / or are used in areas of high or low ambient temperature.

In order to achieve an absolute tightness of the cable lug, it is provided that the soft plastic is a silicone. The application of this cable lug according to the invention is in particular in areas where absolute watertightness is required, but it goes without saying that the application is not limited to this. Silicon is used in particular for applications above 150 ° C.

According to the invention, it is provided that the soft plastic has a Shore A hardness between 40 and 90, preferably between 40 and 70. A Shore A hardness between 60 and 80 indicates the most suitable elastic nature of the soft plastic so as to allow bending of the cable lug into the required geometry. In a preferred embodiment, the Shore A hardness of the soft plastic between 40 and 70, since these soft plastics have the best properties in terms of material hardness for producing a cable lug with overmolding of soft plastic.

In a preferred embodiment of the invention it is provided that the over-molded cable lug is bent at an angle of -90 ° to + 90 ° or over 90 °. For example, the overmolded cable lug can be bent by more than 5 °, 10 °, 20 °, 30 °, 40 °, 50 °, 60 °, 70 °, 80 ° or even more than 90 °. The advantage is that due to the flexibility of the soft plastic, bending of the cable lug after encapsulation with this soft plastic is also possible by more than 90 °. Due to the possibility of strong bending of this overmolded cable lug, it is also possible to apply it in areas in which no overmolded cable lug could hitherto be used, since it was not possible to produce an overmolded cable lug with required tightness using the methods known in the prior art are to manufacture. In particular, it allows the use of the cable lug in areas where absolute watertightness is required.

It goes without saying that the bending of the cable lug is not excluded in other than said angles.

In order to achieve a particularly good conductivity of the molded cable lug is provided that the overmolded cable lug is made of a copper alloy. However, it is not excluded that, depending on the requirement of the cable lug is made of a different metallic conductor.

According to the invention, it is provided that a cable lug is obtained by the described method, wherein it is made possible by the inventive method to realize complex geometries of the cable lug.

BRIEF DESCRIPTION OF THE FIGURES

The invention will now be explained in more detail with reference to an embodiment. The drawings are exemplary and are intended to illustrate the inventive idea, but in no way restrict it or even reproduce it.

• Fig. 1 eine schematische perspektivische Darstellung eines Kabelschuhs ohne Umspritzung;
• Fig. 2 eine schematische perspektivische Darstellung des Kabelschuhs aus Fig. 1 mit Umspritzung;
• Fig. 3 eine schematische perspektivische Darstellung desselben Kabelschuhs mit Umspritzung nach dem Biegen;
• Fig. 4. eine schematische perspektivische Darstellung desselben gebogenen Kabelschuhs mit Umspritzung, durch Pressen und Löten verbunden mit einer Leitung.

Showing:

• Fig. 1 a schematic perspective view of a cable lug without encapsulation;
• Fig. 2 a schematic perspective view of the cable lug Fig. 1 with encapsulation;
• Fig. 3 a schematic perspective view of the same cable lug with encapsulation after bending;
• Fig. 4 , a schematic perspective view of the same bent cable lug with encapsulation, by pressing and soldering connected to a line.

WAYS FOR CARRYING OUT THE INVENTION

In the schematic representation of Fig. 1 is a cable lug 1 without encapsulation 6 shown. The cable lug 1 has two ends. The one end is formed as a loop-shaped pad 2 for conductive connection with another object. The other end of the cable lug 1 has a fork-shaped attachment point 3, to which a line can be fastened on. Between the eye-shaped contact point 2 and the fork-shaped attachment point 3, a planar line section 4 extends, which is here plate-shaped or band-shaped. The line section 4 is angled in the area in front of the fork-shaped attachment point 3 by an angle 5 of 90 °.

In the schematic representation of Fig. 2 is the same cable lug 1 as in Fig. 1 shown, but after overmolding 6 with a soft plastic. The planar line section 4, which extends between the eye-shaped contact point 2 and the fork-shaped attachment point 3, has a directly applied to the planar line section encapsulation 6 made of soft plastic.

In the schematic representation of Fig. 3 is the cable lug 1 with encapsulation 6 off Fig. 2 shown after the bending process. The planar line section 4, around which the encapsulation 6 is arranged directly adjacent, has a bending angle 7 of 90 °. A first section 8 of the planar line section 4 and the eye-shaped contact point 2 are thus normal to a second section 9 of the planar line section 4 and the fork-shaped attachment point. 3

In the schematic representation of Fig. 4 is the same cable lug 1 with encapsulation 5 from the Fig. 3 shown. The fork-shaped attachment point 3 is connected by pressing and soldering with a line 10.

LIST OF REFERENCE NUMBERS

1

lug

2

loop-shaped contact point

3

fork-shaped attachment point

4

plane line section

5

corner

6

encapsulation

7

bending angle

8th

first section

9

second subsection

10

management

Claims (15)

Method for producing lugs (1) with encapsulation (6), characterized in that a soft plastic is overmolded and the method of manufacturing the overmolded lug (1) comprises the following steps: a. Injection of the cable lug (1), and b. Bending the molded cable lug (1). A method according to claim 1, characterized in that the encapsulation (6) of the cable lug (1) takes place by injection molding. Method according to one of claims 1 to 2, characterized in that prior to the encapsulation (6) in step a an adhesive / primer applied to the cable lug (1) or the surface of the cable lug is treated with plasma. Method according to one of claims 1 to 3, characterized in that the soft plastic is a thermoplastic material. Method according to one of claims 1 to 4, characterized in that the soft plastic is an elastomer. Method according to one of claims 1 to 5, characterized in that the soft plastic is a thermoplastic elastomer. Method according to one of claims 1 to 6, characterized in that the soft plastic is an EPDM (ethylene-propylene-diene rubber). Method according to one of claims 1 to 7, characterized in that the soft plastic is a silicone. Method according to one of claims 1 to 8, characterized in that the soft plastic has a Shore A hardness between 40 and 90, preferably between 60 and 80. Method according to one of claims 1 to 9, characterized in that the over-molded cable lug (1) is bent at an angle of -90 ° to + 90 ° or over 90 °. Method according to one of claims 1 to 10, characterized in that the overmolded cable lug (1) is made of a copper alloy. Lug (1) with encapsulation (6), characterized in that the encapsulation (6) is a soft plastic. Lug (1) with encapsulation (6) according to claim 12, characterized in that the soft plastic is a thermoplastic material. Lug (1) with encapsulation (6) according to one of claims 12 to 13, characterized in that the cable lug (1) is made of a copper alloy. Liner (1) with encapsulation (6) obtained by a method according to one of claims 1 to 11.

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