EP3439111B1 - Optimised crimping of two electrical connectors - Google Patents

Description

The invention relates to electrical connectors. More particularly, the invention relates to the crimping of electrical connectors.

In order to electrically and mechanically connect two electrical connectors together, a known method is to crimp a first of these connectors into the second. This consists in inserting the first electrical connector inside the second and in squeezing a section of this assembly in which the second connector covers the first connector. This compression, which must be sufficient to deform the section, makes it possible to ensure the electrical contact between the two connectors and therefore the flow of electricity from one to the other of the connectors. The first connector can be an electrical wire comprising several strands and the second can be a wiring lug. The strands are generally made of copper, but it may be desirable to make them of aluminum for certain applications because of its low density (about three times lower than that of copper).

In practice, it is necessary to carry out successively at least two different crimps. The first is to create an efficient electrical connection between the two connectors. The second consists in creating a solid mechanical connection, in particular in tension, between the two connectors. A third aspect crimping can be provided in order to improve the aesthetics of the whole.

These different crimps make it possible to correctly crimp the first connector in the second connector. However, having to carry out several crimping operations is time consuming and tedious. In addition, it is a source of reduced reproducibility.

US2015364833A1 , EP1658662A1 , US2015364835A1 and EP1503454A1 each disclose the crimping of connectors between them.

An object of the invention is to overcome these drawbacks by simplifying the crimping of the first connector in the second connector.

For this purpose, according to the invention, a crimping method according to claim 1 is provided.

Thus, by virtue of the different shapes of the walls of the mold in zones which follow one another along a main axis of the connectors, two crimping operations which can have different functions, for example an electrical crimping and a mechanical crimping, are produced in one operation. It follows that the crimping of the first connector in the second connector is considerably simplified.

In addition, the relative position of the two areas of the walls of the mold is fixed and known. The reproducibility of the crimping is thus improved in that it makes it possible to guarantee the adjacency of the two pressed zones of the assembly.

Advantageously, in a section perpendicular to the main axis, each wall has a general shape of “W”.

The walls are thus simple to produce and allow effective pressurization.

Advantageously, once the mold is closed, the walls form cavities of different areas in the zones in sections perpendicular to the main axis.

The possibility of choosing the areas of these cavities allows quantitative adjustment of the electrical and mechanical properties of the crimping.

Advantageously, the first wall of the mold forming a fixed die, a punch carrying the second wall is pressed in the direction of the first wall.

The crimping is thus done in a simple way, by pressing the punch in the direction of the die. In addition, the crimping can easily be configured with the punch. In other words, by changing the punch, the shape of the pressed areas of the assembly can be changed during crimping. Flexibility is therefore provided in the crimping process.

According to the invention, the second connector has ridges on an internal surface.

Thus, during crimping, the ridges of the second connector make it possible to create a plurality of pressure points on the first connector, which allows the second connector to grip the first connector. The tensile strength of the assembly is thus improved, which contributes to improving the mechanical properties of the crimping.

This is even more advantageous if the first electrical connector is made of aluminum. In fact, the pressure points created by the second connector make it possible to break an insulating layer of alumina which forms on the surface of the first connector by oxidation. This constraint is therefore overcome, which makes it possible to improve the electrical properties of the assembly.

A set of first and second electrical connectors as defined in claim 4 is also provided according to the invention.

According to the invention, the second connector has ridges on an internal surface.

Thus, during crimping, the ridges of the second connector make it possible to create a plurality of pressure points on the first connector which make it possible to break the layer of alumina which forms on the surface of the strands if they are made in aluminum. This constraint is therefore overcome, which makes it possible to improve the electrical properties of the assembly.

Additionally, the plurality of pressure points allow the second connector to grip the first connector. The tensile strength of the assembly is thus improved, which contributes to improving the mechanical properties of the crimping.

Finally, the ridges make it possible to increase the contact surface between the first and second connectors, which improves the electrical conduction between them.

Preferably, the ridges extend helically over the inner surface of the second connector.

These ridges are simple to produce and allow the first connector to be gripped effectively.

Preferably the ridges form an angle of between 10 and 80 ° with a main axis of the assembly.

Preferably, the second connector is made from a copper alloy.

The second connector is thus made of a material having a hardness greater than that of aluminum, which facilitates the breaking of the layer of alumina in the case where the first connector is made of aluminum.

• la figure 1 est une vue éclatée d'un ensemble d'un premier et d'un second connecteurs électriques selon l'invention, avant sertissage,
• la figure 2 est une vue schématique de l'ensemble de la figure 1 après sertissage,
• la figure 3 est une vue en perspective d'une extrémité du second connecteur électrique de l'ensemble de la figure 1,
• la figure 4 est une vue à grande échelle illustrant un moule utilisé pour sertir l'ensemble de la figure 1,
• les figures 5a et 5b illustrent la configuration du moule de la figure 4 une fois fermé, dans deux sections différentes, et
• les figures 6a et 6b sont des vues en section des deux zones de l'ensemble après sertissage.

An embodiment of the invention will now be described in support of the appended drawings in which:

• the figure 1 is an exploded view of an assembly of first and second electrical connectors according to the invention, before crimping,
• the figure 2 is a schematic view of the entire figure 1 after crimping,
• the figure 3 is a perspective view of one end of the second electrical connector of the assembly of the figure 1 ,
• the figure 4 is an enlarged view showing a mold used to crimp the assembly of the figure 1 ,
• the figures 5a and 5b illustrate the mold configuration of the figure 4 once closed, in two different sections, and
• the figures 6a and 6b are sectional views of the two areas of the assembly after crimping.

We illustrated in figure 1 an assembly 2 according to the invention. The set 2 includes first 4 and second 6 electrical connectors. The first connector 4 is intended to be crimped in the second connector 6. The first and second connectors 4, 6 are here generally cylindrical in shape and have main axes coinciding with a main axis 8 of the assembly 2.

The first connector 4 is formed by an electric wire comprising one or more strands 10 made of an electrically conductive material. In what follows, we will consider that the strands 10 are made of aluminum, but it can very well be provided that they are made of any other conductive material, for example any metal.

The second connector 6 has at one axial end an opening 11, the dimensions of which allow the insertion of the first connector 4. The second connector 6 is here formed by a wiring lug and comprises a tab 12 allowing its subsequent fixing.

The second connector 6 is made of a material having a hardness greater than that of the material in which the strands 10 of the first connector 4 are made. The strands 10 being made of aluminum, one can for example choose to make the second connector 6 in a relatively inexpensive copper alloy. However, you can choose another material for the second connector 6.

With reference to the figure 3 , the second connector 6 has striations 20 on an internal surface. These stripes 20 extend helically on the internal surface of the second connector 6, here at an angle approximately equal to 45 ° with the axis 8. In general, the stripes ridges 20 form an angle between 10 and 80 ° with the axis 8.

We illustrated in figure 4 a mold 21 used to crimp the first connector 4 in the second connector 6. The mold 21 comprises a die 22 and a punch 24 respectively forming first and second parts of the mold 21.

The die 22 has a wall having different shapes in two zones 22a, 22b which follow one another along the axis 8. Likewise, the punch 24 has a wall having different shapes in two zones 24a, 24b which follow each other. along axis 8. When the mold is closed, zone 22a is located opposite zone 24a and zone 22b is located opposite zone 24b. In section perpendicular to the axis 8, and in each of the zones 22a, 22b, 24a and 24b, each wall has a general shape of “W”.

As can be seen on the figures 5a and 5b , once the mold 21 is closed, the walls form cavities of different areas in the zones in sections perpendicular to the axis 8.

To perform the crimping of the first connector 4 in the second connector 6, the procedure is as follows.

First, the first connector 4 is inserted into the second connector 6. This is permitted by the dimensions of the connectors 4, 6 as stated in the above.

Then, the assembly 2 is placed in the die 22 so that a section 14 of the assembly 2 in which the two connectors 4, 6 are radially superimposed can be pressed into the mold 21.

Finally, the punch 24 is pressed in the direction of the die 22 so as to compress the section 14. The mold 21 then occupies the configuration illustrated in figures 5a and 5b . The figure 5a is a section comprising areas 22a and 24a, and the figure 5b is a section comprising Figures 22b and 24b.

The assembly 2 resulting from this crimping process is illustrated in figure 2 . The section 14 is formed by zones 16 and 18 in which the assembly 2 is compressed. Zone 16 of section 14 has been compressed by zones 22a and 24a of mold 21, and zone 18 of section 14 has been compressed by zones 22b and 24b of mold 21. A double crimping has thus been produced having two different functions. : an electrical crimping and a mechanical crimping.

Zone 16, namely the least compressed zone, is located closer to the opening 11 of the second connector 6 than the zone 18. Otherwise, the zone 18 would create a zone of mechanical weakness of the assembly 2. And there is also the risk of cutting the first connector 4 during crimping. In other words, the arrangement of zones 16 and 18 is chosen to maximize the mechanical and electrical performance of assembly 2.

The figures 6a and 6b illustrate more precisely the state of the first and second connectors 4, 6 after crimping. The figure 6a is a section including zone 16, and the figure 6b is a section comprising zone 18. It is observed in particular that the strands 10 and the second connector 6 are compressed and take the form of the walls of the mold 21.

In particular, the second connector 6 has two opposite outer faces 6A, 6B, each outer face 6A, 6B having the shape of a respective wall of the mold 21. Thus, each outer face 6A, 6B has different shapes in the two zones. 16, 18. Each external face 6A, 6B has here, in section perpendicular to the main axis 8 and in each of the zones 16, 18, a general shape of “W”.

Furthermore, the assembly formed by the first and second connectors 4, 6 has different areas in the zones 16, 18, in section perpendicular to the main axis 8.

Thanks to this compression, a large contact surface is created between the first and second connectors 4, 6, which allows the mechanical retention of the assembly and ensures good electrical conductivity between the two connectors 4, 6.

It can also be seen that the ridges 20 of the second connector 6 penetrate into the strands 10. This is permitted by the fact that the second connector 6 is made in a material having a hardness greater than that of the material in which the strands 10 are made. As a result, the striations 20 can break the alumina layer forming at the second connector 6 / strands 10 interface. And the penetration of the striations 20 improves the resistance to tearing of the assembly 2.

Of course, numerous modifications can be made to the invention without departing from the scope of the claims.

Claims (10)

1. A method for crimping a first connector (4) in a second connector (6), wherein the two connectors (4, 6) are pressed between first and second walls of a mold (21), these walls each having different shapes in zones following one another along a main axis (8) of the connectors (4, 6), wherein, in cross-section perpendicular to the main axis (8), and in each of the zones, each wall is generally W-shaped, and wherein the second connector (6) has ridges (20) on an inner surface.
2. The method according to the preceding claim, wherein, once the mold (21) is closed, the walls form cavities of different areas in the zones in cross-sections perpendicular to the main axis (8).
3. The method according to any one of the preceding claims, wherein, the first wall of the mold (21) forming a fixed die (22), a punch (24) bearing the second wall is pressed toward the first wall.
4. An assembly (2) of a first and a second electrical connector (4, 6), wherein the first connector (4) is crimped in the second connector (6), the assembly (2) comprising at least two zones, following one another along a main axis (8) of the connectors (4, 6), in which the connectors (4, 6) are pressed, the connectors (4, 6) having different shapes in the two zones in cross-sections perpendicular to the main axis (8), wherein the shapes are obtained by pressing the two connectors (4, 6) between first and second walls of a mold (21), each of these walls having different shapes in the two zones, and wherein each wall is, in cross-section perpendicular to the main axis (8) and in each of the zones, generally W-shaped and wherein the second connector (6) has ridges (20) on an inner surface.
5. The assembly according to claim 4, wherein the second connector has two opposite outer faces (6A, 6B), each outer face (6A, 6B) having different shapes in the two zones (16, 18).
6. The assembly according to claim 5, wherein each face is generally W-shaped in cross-section perpendicular to the main axis (8) and in each of the zones (16, 18).
7. The assembly according to any one of claims 4 to 6, having different areas in the zones (16, 18) in cross-sections perpendicular to the main axis (8).
8. The assembly (2) according to claim 7, wherein the ridges (20) extend helically over the inner surface of the second connector (6).
9. The assembly (2) according to any one of claims 4 to 8, wherein the ridges (20) form an angle comprised between 10 and 80° with a main axis (8) of the assembly (2).
10. The assembly (2) according to any one of claims 4 to 9, wherein the second connector (6) is made from a cuprous alloy.

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