WO2020224705A1

WO2020224705A1 - Method for detaching an insulation layer from a conductor wire end

Info

Publication number: WO2020224705A1
Application number: PCT/DE2020/100329
Authority: WO
Inventors: Stefan Riess
Original assignee: Schaeffler Technologies AG & Co. KG
Priority date: 2019-05-03
Filing date: 2020-04-22
Publication date: 2020-11-12
Also published as: DE102019111438A1; CN113767441A; DE102019111438B4; CN113767441B

Abstract

The invention relates to a method and an apparatus (3) for detaching an insulation layer (1) from an end of a conductor wire (2). The insulator layer is connected to conductor by means of an adhesion layer (9), wherein said adhesion layer is destroyed between the conductor wire (2) and the insulation layer (1) such that surface pressure is repeatedly applied to the entire surface of the insulation layer to be detached.

Description

Method for peeling off an insulation layer from a conductor wire end

The invention relates to a method and a device for detaching an Isolati onsschicht from a conductor wire end. Such a device and such a method are used, for example, where electrical conductors have to be contacted.

Electrical conductor wires, to which strands are also summed up in the present application, are provided with an insulating jacket in many applications for functional reasons and / or to ensure contact protection. For example, the winding wires of electrical machines are often coated with an insulating varnish. Often wire insulation made of a thermoplastic mate rial are used. These can be connected to the surface of the conductor via an adhesion layer, which is created, for example, by gluing or heating as a boundary layer between the conductor and the insulating jacket. Paper is also known as an insulation material for lead wires and, in particular, winding wires.

In particular, for the purpose of making contact with other wires, busbars or cable lugs, for example, such insulation layers must be partially removed. Various methods for this purpose are known from the prior art. In the case of enamelled wires, for example, the area in which the insulation has to be removed is brushed off by machine. In contrast, wires with a thermoplastic insulation jacket are often stripped using a cutting device that can be adjusted to the remaining wire diameter. If the thermoplastic insulation jacket is not glued to the conductor wire, the insulation material to be removed can simply be removed after the cut.

In particular for stripping thermoplastically insulated wires is off

EP 0 180 893 B1 discloses a method in which a comb-like slit and equipped in the transverse direction with a groove the size of the wire diameter

Fusible link is pressed onto the wire with a defined force during brief heating. The invention is based on the object of specifying a simple method suitable for series production for the removal of an insulation layer connected to a conductor wire via an adhesive layer, in which damage to the conductor is avoided.

This object is achieved by a method with the features according to patent claim 1. Furthermore, the object is achieved by a device having the features of 8 Pa tentanspruchs. Advantageous embodiments of the invention can be found in the dependent claims.

The invention is based on the knowledge that an insulation layer which is bonded to the surface of a conductor wire via an adhesion layer can be removed by repeatedly exerting surface pressure on the entire surface of the insulation layer to be detached. Due to the flat and periodic application of pressure on the surface of the insulation jacket, for example, the insulation material starts to flow at the interface between the conductor and the insulation jacket and thus dissolves the adhesive forces. This flow process can be initiated without the supply of heat. Heatable press jaws or other devices for heating the insulation jacket are not required.

The method is particularly suitable for a conductor whose insulation layer contains a thermoplastic, in particular polyetheretherketone (also abbreviated to PEEK). Thermoplastic insulation materials are also increasingly being used for windings in dynamo-electric machines. In addition to the thermoplastic, the insulation layer can also contain other materials, for example a thermosetting material or an insulating varnish. In particular, when the thermoplastic part of the insulation layer is a layer of the insulating jacket on the inside of the jacket and therefore the contact area to the conductor surface, this thermoplastic insulating material begins to flow in the interface area between the insulating jacket and the electrical conductor due to the periodic surface pressure. As a consequence, the adhesive layer dissolves, so that the insulating jacket is detached from the conductor. In this context, in particular, it has been shown that the method has clear advantages over the current methods for removing the insulation material. Because the process avoids any pollution that wisely can be caused by a cutting blade. This means that the periodic surface pressing does not create any metal chips that could cause a short circuit.

In the case of an insulating jacket with a full thermoplastic layer on the inside of the jacket, the detachment by periodic surface pressing is very easy and reliable, which is due to the flow process on the conductor surface.

However, it is also conceivable to use the method with an insulating jacket that is connected to the electrical conductor via a thermoset layer. For example, a cured resin can be located between the conductor and a thermoplastic Isolierman tel that causes the adhesion between the conductor and the insulating jacket. Due to the repeated, periodic surface pressure, the resin breaks up, so that the adhesive layer is destroyed.

In order to remove the insulation layer at the point to be stripped, it must not only be detached from the conductor wire underneath, but also separated from the rest of the insulation material that is to remain on the conductor wire. The necessary break of the insulation material along its circumference can also occur through the repeated application of the surface pressure. It is even possible to dispense with the use of a cutting tool for separating insulating material that has been detached from the conductor surface. Alternatively, the thermoplastic material detached from the conductor can also be detached from the remaining insulating jacket, which is still adhesively connected to the conductor, by a cut along the circumference of the conductor.

The method can be carried out in such a way that when the pressing force is repeatedly applied to the insulating jacket, no displacement forces and no torques are exerted on the insulating jacket and the conductor surrounded by the insulating jacket. Damage to the conductor cross-section can be avoided by applying the pressing forces that are neutral in terms of displacement and torque. In addition, pollution from the abrasion of insulation material is avoided, which is unavoidable in current methods that work with a cutting blade. Since there is no force in the length and width of the wire during the process is initiated, for example, damage to a stator winding of an electrical machine can be effectively avoided.

Due to the surface pressure on the entire surface of the insulation layer to be detached, the insulation end can be defined very precisely on the entire wire circumference.For example, if the method is applied to a conductor wire with a rectangular cross-section and the surface pressure is applied with at least one first pair of opposing pressing jaws to an intermediate one If the wire section is stripped off, it is automatically ensured that the area of the conductor freed from the insulation is almost exactly defined by the dimensions of the pressing jaws.

The two opposite pressing jaws can first destroy the adhesion layer of the insulation jacket on two opposite surfaces of the rectangular conductor wire. In a further process step, either the opposite pressing jaws can now be rotated by 90 ° or the conductor wire located between the two opposite pressing jaws. After this turning process, the remaining opposing surfaces of the insulation jacket can be released from the wire wire by repeatedly applying the pressing force. The detached part of the insulation jacket can then be pushed off the conductor wire. In an alternative embodiment of the method, the repeated pressing takes place on the remaining, opposing surfaces of the insulation jacket with a second pair of opposing pressing jaws, the second pair being arranged offset by 90 degrees to the first pair when viewed in the circumferential direction of the wire. In such an embodiment of the invention, it is conceivable that the surface pressures by the said pairs of pressing jaws that are opposite one another and offset by 90 ° to one another always occur alternately.

In an alternative embodiment of the invention, the method is applied to a conductor wire with a round cross-section. Here, the surface pressure is carried out with, for example, three pressing jaws, each offset by 120 degrees from one another, onto the wire section to be stripped in between. The invention further comprises a device for detaching an insulation layer from a conductor wire, which is connected to the conductor wire via an adhesive layer, with at least one press jaw for repeatedly exerting a surface pressure on the entire surface of the insulation layer to be detached with a pressing force that interferes with the adhesive layer the conductor wire and the insulation layer destroyed.

Such a device has, for example, at least two pairs of opposing press jaws, each press jaw being actuatable by a rocker arm. The rocker arm is driven, for example, via a rotating elliptical shaft. Due to the elliptical wave shape, the rotation of the shaft is converted into a translatory movement of the rocker arm, which in turn exerts the necessary pressure on the press jaws and thus on the insulating jacket.

At least one press jaw can have a raised edge to cut off the insulation material released by the pressure application. This edge does not primarily serve as a cutting edge here at least. The separation of the insulation jacket from the conductor wire occurs primarily through the surface pressure and the destruction of the adhesive layer caused by this. The raised edge is primarily used to carry along the dissolved insulation material when it is pulled off the wire.

The invention is explained in more detail below with the aid of the exemplary embodiments shown in the figures. Show it:

1 shows a conductor wire with an insulation layer,

FIG. 2 shows the conductor wire according to FIG. 1 in cross section,

3 shows a method for removing the insulation layer at one end of the

Conductor wire,

4 shows the conductor wire after the method has been carried out,

FIG. 5 shows a sectional view of a device for performing the method for removing the insulation layer and

FIG. 6 shows a sectional illustration of a press jaw of the device according to FIG. 5 1 shows a conductor wire 2 with an insulation layer 1 with a rectangular conductor wire cross section. It is the winding wire of a stator of a dynamo-electric machine, a so-called flat wire winding. With the flat wire winding, a high copper fill factor can be achieved in the grooves of the electrical machine, which results in a high energy density in the electrical machine.

The insulation layer 1 consists of polyetheretherketone, also abbreviated to PEEK. This is a thermoplastic material. The PEEK insulation is connected to the conductor wire 2 via an adhesive layer 9. This can be seen in Figure 2, which shows the conductor wire 2, the insulation layer 1 and the adhesive layer 9 in cross section. The adhesive layer 9 can be produced, for example, by briefly heating the insulating jacket. It is also conceivable to connect the insulating jacket to the conductor via an adhesive to create the adhesive layer 9. Various activators can also be used to ensure the adhesive forces between the insulating layer 1 and the conductor wire 2 underneath.

3 shows a method for removing the insulation layer 1 at one end of the conductor wire 2. In the method, a first pair of opposing pressing jaws 3 and a second pair of opposing pressing jaws 4 act exactly on the area of the insulating layer 1 that is covered by the conductor wire 2 should be removed. The two pairs of opposing press jaws 3, 4 - also denoted by the letters A for the first pair 3 and B for the second pair 4 in the figure - alternately and periodically exert a surface pressure on the entire surface of the insulation layer 1 to be detached. First, the pressing jaws A of the first pair 3 are pressed against one another while the second pair of pressing jaws 4 or B lying opposite one another is relieved. Then the first pair of opposing press jaws 3 is relieved and the surface pressure is applied from the second pair of opposing press jaws 4 to the surface of the insulation jacket. This alternating loading and unloading of the opposing pairs of pressing jaws 3, 4 is repeated cyclically. The process is repeated until the Adhäsi onsschicht 9 between the insulation layer 1 and the conductor wire 2 is destroyed below the respective press jaws. In this case, the pair of pressing jaws 3, 4 opposite one another is not necessarily to be changed after each pressing process. It is also conceivable that the pressure is initially built up and relieved again several times in succession via the first pair of opposing pressing jaws 3, while the second pair of opposing pressing jaws 4 remains relieved. The process can initially be carried out until the adhesive layer 9 below the first pair of opposing press jaws 3 is destroyed. Subsequently, the first pair of opposing pressing jaws 3 is relieved, while the second pair of opposing pressing jaws 4 periodically exert pressure on the surface area of the insulation layer 1 lying below.

Regardless of whether a constant alternation of the two pairs of opposite pressing jaws 3, 4 is carried out or other types of cycles are used when pressing sen, the forces are always impressed in the insulation layer 1 in a displacement and moment-neutral manner. This prevents damage to the cross-section of the conductor. Because only pressing forces are exerted on the conductor surface and the insulation jacket surrounding it, there is no insulation abrasion. Soiling caused by this can thus be avoided.

The stripped area of the insulation layer 1 is clearly defined by the geometry of the press jaws. Correspondingly, there is also a defined insulation end on the entire circumference of the wire. It is also ensured that the entire area up to the end of the wire is free of insulation.

FIG. 4 shows the conductor wire 2 after the method has been carried out, as described in connection with FIG. After repeated surface pressing, the adhesive layer between the insulation jacket and the conductor wire 2 underneath is completely destroyed. The pressing jaws have finally also led to a break within the insulation layer 1 at the edge of the respective pressing jaws as a result of the pressure they exert, so that the insulating jacket can simply be pulled off. This separation of the insulation jacket along its circumferential direction does not require any cutting tool. The use of cutting edges for stripping always involves the risk of chips being detached from the conductor wire material and this can cause a short circuit in the electrical system. This risk can be effectively excluded using the procedure described here.

5 shows a sectional view of a device for carrying out the method for removing the insulation layer 1. The device comprises four rocker arms 5, two of which are opposite each other and at the end of which the pairs of opposite pressing jaws 3, 4, which have already been described several times, are arranged. A first pair of rocker arms 5 comprises the first pair of opposing press jaws 3, while a second pair of rocker arms 5, which is arranged rotated by 90 ° with respect to the first pair of rocker arms 5, comprises the second pair of opposing press jaws 4.

The rocker arms 5 are mounted on rollers 10 at one end of a shaft 6 with an elliptical cross section. The shaft 6 is rotated and, due to the rotational movement, causes the pressing jaws of the first pair of rocker arms and the second pair of rocker arms to be pressed onto the insulation layer 1 in between. In this way, a very simple device is provided with the aid of which the surface pressure is carried out repeatedly and always alternately by the first pair of opposing pressing jaws 3 and the second pair of opposing pressing jaws 4.

6 shows a sectional view of a pressing jaw of the device according to FIG. 5. The pressing jaw comprises a raised edge 7 at one end. This raised edge 7 is used to break the insulation jacket, which is located in the circumferential direction between the part of the insulation to be removed and the remaining part the isolation he stretches, supports. Furthermore, the raised edge 7 helps to strip off the loosened part of the insulation jacket from the conductor wire 2. Reference list of insulation layer

Conductor wire

first pair of opposite pressing jaws second pair of opposite pressing jaws rocker arms

wave

Edge

Wire section to be stripped

Adhesion layer

roll

Claims

1. A method for detaching an insulation layer (1) from a conductor wire (2) which is connected to the conductor via an adhesion layer (9), the adhesion layer (9) between the conductor wire (2) and the insulation layer (1) thereby is destroyed that a surface pressure is repeatedly exerted on the entire surface to be detached of the insulation layer (1).

2. The method according to claim 1, wherein the insulation layer (1) has a thermoplastic insulation layer (1) which is in contact with the surface of the conductor wire (2).

3. The method according to any one of claims 1 or 2, wherein the method is carried out without supply of heat.

4. The method according to any one of the preceding claims, wherein the method is applied to a conductor wire (2) with a rectangular cross-section and the surface pressing is carried out with at least one first pair (3) of opposing press jaws on an intermediate wire section (8) to be stripped.

5. The method according to claim 4, wherein the method is carried out with a second pair (4) of opposing pressing jaws on the intermediate wire section to be stripped, the second pair being arranged offset by 90 degrees to the first pair in the circumferential direction of the wire.

6. The method according to any one of claims 1 to 3, wherein the method is applied to a Lei terdraht (2) with a round cross-section and the surface pressure is carried out with three pressing jaws offset by 120 degrees to each other on the wire section to be stripped in between.

7. The method according to any one of the preceding claims, wherein the conductor wire is a winding wire of an electrical machine.

8. Device for detaching an insulation layer (1) from a conductor wire (2), which is connected to the conductor wire (2) via an adhesive layer (9), with at least one pressing jaw for repeatedly exerting surface pressure on the entire surface of the insulation layer to be detached ( 1) with a pressing force that destroys the adhesive layer (9) between the conductor wire (2) and the insulation layer (1).

9. The device according to claim 8, with at least two pairs (3, 4) opposing gender press jaws, each press jaw being actuated by a rocker arm (5) which is driven via a rotating elliptical shaft (6).

10. Device according to one of the preceding claims, wherein the at least one press jaw has a raised edge (7) which is provided for separating the insulation material released by the pressure application.