ES2902205T3 - Electrical connection element provided with a contact element and its manufacturing process - Google Patents

Abstract

Electrical connection element (1) comprising a metallic conductive body (100) made of a first material and housing a spring sheet (200), said spring sheet (200) being adapted to apply against an internal face of a wall (103) of the body (100) the stripped core (4) of a conductive cable (2) inserted in said connection element (1), characterized in that this internal face of the wall (103) of the body (100) is provided of a contact element (115) made of a second material different from the first material, against which said spring blade (200) is adapted to engage said bare core (4) of the conductive cable (2) when the latter is inserted into the connection element (1), said second material presenting a contact resistance with the bare core of the electrical cable that is lower than the contact resistance between the first material and this bare core of the electrical cable.

Description

DESCRIPTION

Electrical connection element provided with a contact element and its manufacturing method Technical field to which the invention relates

The present invention relates to an electrical connection element according to the preamble of claim 1.

It also relates to a method used to manufacture said electrical connection element.

technological background

Such connection elements as described in the introduction, for example for electrical sockets, are known.

The function of said connection element is to transport the current between the electrical cables of the electrical network and the electrical plug belonging to an electrical switchgear that is plugged into this connection element. To this end, the connection element comprises a part adapted to receive an electric cable coming from the wall and a receiving socket adapted to receive the plug of the electric socket in order to bring them into electrical contact.

Said electrical connection element must be in accordance with certain standards.

For example, international standards require that the temperature rise of an electrical outlet due to its heating in operation remain below a threshold value of heating established based on the current rating of the electrical outlet.

One solution to reduce heating of the connection element is to make the body of the connection element from a material that has as low an electrical resistance as possible, this body being completely covered with a coating that limits the contact resistance with the bare core. of the electrical cable. Indeed, the heating of the connecting element increases with the electrical resistance introduced by the latter in the electrical circuit.

The electrical resistance of the connection element is related to different parameters, in particular with the volumic resistance of the material (related to its conductivity) and with the contact resistance between the bare core of the electrical cable and the connection element. The body is usually made of raw brass. It is also known to make it entirely in brass covered with materials such as tin, silver or gold. This makes it possible to obtain a contact resistance with the bare core of an electrical cable that is lower than the contact resistance between the raw brass and the bare core of the electrical cable. However, the cost of such coated brass is high.

An example of a connection element is described, for example, in document EP1353407.

Object of the invention

In this context, the present invention proposes a connection element in which heating is reduced when the electrical connection of an electrical cable takes place while limiting costs.

More particularly, an electrical connection element according to claim 1 is proposed according to the invention.

Thanks to the connection element according to the invention, it is possible to limit the heating of the body of this connection element when the electric current passes by reducing the contact resistance between the bare core of the electric cable and the body, while limiting the manufacturing costs of the connecting element. This is done thanks to a contact element made of a material that has a contact resistance with the bare core of the electrical cable that is lower than that of the material in which the rest of the connection element is made and arranged inside the connection element. Connection.

Other non-limiting and advantageous characteristics of the connection element according to the invention are indicated in claims 2 to 8.

As a variant, at least two contact elements made of the second material are provided, and said spring blade is adapted to apply the bare core of the electrical cable against the two contact elements simultaneously.

The invention also relates to an electrical switchgear according to one of claims 9 and 10. In particular, this electrical switchgear constitutes a socket for the electrical connection of said electric cable and a connection plug belonging to another electrical switchgear. .

Finally, the invention relates to a method for manufacturing an electrical connection element such as the one described above, according to one of claims 11 to 13.

Detailed description of an exemplary embodiment

The following description with respect to the attached drawings, given by way of non-limiting examples, will make it clear what the invention consists of and how it can be carried out.

In the attached drawings:

Figure 1 is a schematic rear perspective view of a first example of embodiment of the electrical connection element according to the invention,

Figure 2 is a schematic rear perspective view of the body of the electrical connection element of Figure 1,

- figure 3 is a schematic rear perspective view of the spring blade of the electrical connection element of figure 1,

- figure 4 is a rear view of the connection element of figure 1,

Figure 5 is a schematic front perspective view of the electrical connection element of Figure 1,

Figure 6 is a schematic front perspective view of the body of the electrical connection element of Figure 5,

Figure 7 is a schematic front perspective view of the spring blade of the electrical connection element of Figure 5,

- figure 8 is a schematic top view of the electrical connection element of figure 1, - figure 9 is a schematic top view of the body of the electrical connection element of figure 8,

- figure 10 is a schematic view from above of the spring blade of the electrical connection element of figure 8,

- figure 11 is a schematic profile view of the electrical connection element of figure 1,

- figure 12 is a schematic profile view of the spring leaf of the connection element of figure 11,

Figure 13 is a schematic exploded front perspective view of the electrical connection element of Figure 5,

- figure 14 is a schematic exploded rear perspective view of the electrical connection element of figure 1,

figure 15 is a schematic section view according to the plane P1 of figure 8,

- figure 16 is a schematic sectional view, similar to that of figure 15, with the bare core of an electric cable inserted in the connection element,

Figure 17 is a schematic rear perspective view of a second example of embodiment of the electrical connection element according to the invention,

figure 18 is a schematic sectional view similar to that of figure 16 for the second example of embodiment.

In the two embodiments shown, the identical or corresponding elements will be referenced with the same symbols.

In figures 1 to 16, on the one hand, and 17 to 18, on the other hand, two embodiments of the connecting element 1 according to the invention are shown.

The connection element 1 according to the invention is intended to be integrated into electrical equipment, for example into a power outlet.

The electrical switchgear according to the invention comprises at least one connection element for the electrical connection of an electrical cable.

In particular, this electrical switchgear constitutes a current socket for the electrical connection of said electrical cable and a connection plug belonging to another electrical switchgear.

It allows the transport of electrical current between the electrical cables of this switchgear, for example the electrical cables of the electrical network connected to the power outlet, and a connection plug plugged into this electrical switchgear, belonging, for example, to a plug electrical from other electrical equipment.

This connection element 1 comprises, for this purpose, a conductive body 100 comprising a housing 110 adapted to receive at least one bare core 4 of an electric cable 2 (figures 16 and 18) and a socket 120 adapted to receive the plug connector of the electrical plug (not shown) to bring the electrical cable into electrical contact with the connection plug.

The connection element 1 further comprises a spring blade 200 adapted, on the one hand, to press the electric cable 2 inserted in the housing 110 against a base wall 103 of this housing 110, and, on the other hand, to press the plug inserted into the connection socket 120 (figures 1, 5, 8, 11, 13, 14, 15, 16, 17 and 18).

The electric cable 2 more precisely comprises a bare core 4 wrapped in an insulating sheath (FIGS. 16 and 18).

More precisely, in this case, the spring blade 200 is adapted to apply the bare core 4 of the conductor cable 2 inserted in the housing 110 against the base wall 103 (figures 16 and 18) of this housing 110, and is adapted to applying at least one wall of the connection socket 120 against the connection pin, when the latter is inserted into said connection socket 120.

The connection element 1 generally extends along a longitudinal axis X1 orthogonal to a direction of insertion I of the connection pin in the socket 120. The direction of insertion I corresponds to the longitudinal axis of the receiving socket 120 (figures 1, 5, 8, 13, 14 and 17).

The body 100 of the connection element 1 is more particularly represented in figures 1, 2, 4, 5, 6, 8, 9, 11, 13, 14 and 17.

The body 100 is made of a first material that has a first satisfactory electrical conductivity to conduct the electrical current between the connection plug and the electrical cable 2.

It is, for example, a conductive metal, for example copper or a copper-containing alloy.

The body 100 is formed in this case by a folded metal strip.

This body 100 comprises in this case two lateral wings 101, 102 extending from the base wall 103, globally along the longitudinal axis X1.

The base wall 103 is substantially flat and extends perpendicular to the longitudinal axis X1 of the connecting element 1 (figures 8, 9 and 17).

Each lateral wing 101, 102 forms, successively from the base wall 103, a main lateral wall 111, 112 of the housing 110, an intermediate part 121, 122 curved inwards of the connecting element 1 and a curved wall 123, 124 towards the outside of the connection element, which partially delimits the alveolus 120 (figures 1, 2, 5, 6, 8, 9, 13, 14 and 17).

The side walls 111, 112 of the housing 110, defined by the two side wings 101, 102, are flat and extend at right angles from the base wall 103.

This base wall 103 then forms a third side wall of the housing 110 (figures 1, 2, 4, 5, 8, 9 and The housing 110 of the connection element 1 then has a generally parallelepiped shape delimited by the two main side walls 111, 112, the base wall 103 and said intermediate portions 121, 122 of the side wings 101, 102 (figures 1, 2, 5, 6, 8, 9, 13, 14 and 17).

This housing 110 is thus practically closed on four faces by said side walls 111, 112, 103, and said intermediate portions 121, 122 of the side wings 101, 102.

It is completely open on two opposite faces.

The housing 110 thus constitutes an insertion space for the electrical cable in the connection element 100, which in this case extends along a direction E1 parallel to the insertion direction I of the connection plug in the socket (FIGS. 2, 6, 9 and 11).

The direction E1 of insertion of the electrical cable is, in this case, therefore, orthogonal to the longitudinal axis X1 of the connection element 1.

Housing 110 is open along this direction E1.

In addition, the base wall 103 of the housing 110 has an opening 105, which forms two low walls 106 that rise from the internal face of this base wall 103, parallel to the side walls 111, 112 of the housing 110 (figures 5 , 6, 8, 9 and 17), into the housing 110.

These low walls 106 extend longitudinally along the direction E1 of insertion of the electrical cable in the housing, over a large part of the height of the housing 110 (FIGS. 1, 2, 5, 6, 8, 9, 13, 14 and 17).

Thus, each low wall 106 delimits with the side wall 111, 112 of the adjacent housing 110, an insertion corridor 107, 108 (figure 9) of the bare core 4 of the electric cable 2, which guides the introduction of the bare core 4 of the electric cable 2 in this accommodation 110.

Notably, the internal face of the base wall 103 of the body 100 is also provided with a contact element 115 (figures 8, 9, 15, 16, 19) made of a second material that has a contact resistance with the bare core of the electric cable less than the contact resistance between the first material and this bare core of the electric cable, against which said spring blade 200 is adapted to apply said bare core 4 of the conductor cable 2 when the latter is inserted into the connection element 1. This second material is different from the first material.

It is a contact element that has small dimensions with respect to the dimensions of the base wall.

This contact element 115 thus has a limited extension with respect to that of the base wall 103. However, it can have different shapes. It can be in particular in the form of a contact grain or a tablet, but other shapes, for example a strip shape, are also possible.

In particular, the contact element 115 can have a circular shape, with a diameter between 1 and 2 millimeters, for example equal to 1.5 millimeters. It can also have any other appropriate shape, with, for example, a total dimension between 1 and 2 millimeters. The corresponding dimensions of the receptacle are in this case, for example, 8 millimeters wide and 11 millimeters high, along the insertion direction E1 for the base wall 103, and 7 millimeters long along the axis longitudinal X1. The total length of the connecting element along this longitudinal axis X1 is in this case 18 millimeters.

Each contact element 115 is fixed on the inner face of the base wall 103. In particular, each contact element 115 is fixed on or on the base wall 103.

It can also be provided that the base wall 103 comprises a plurality of contact elements 115 against which the spring blade 200 is adapted to apply simultaneously or not the bare core 4 of the electrical cable 2.

Each contact element 115 is adapted to direct electrical current from the bare core of the electrical cable in contact with it to the body 100.

Body 100 is adapted to direct electrical current from each contact element 115 to the connection plug plugged into receiving socket 120.

In the first example of embodiment represented in FIGS. 1 to 16, as shown more particularly in FIGS. 1, 2 and 4, the connection element 1 comprises in this case more precisely two contact elements 115.

The contact elements 115 are arranged on the internal face of the base wall 103, in such a way that the spring blade 200 applies the bare core 4 of the electrical cable 2 inserted in the housing 110 against at least one of the contact elements. contact 115.

In practice, in this case, each contact element 115 is arranged in one of the insertion corridors 107, 108 delimited between the low walls 106 and the adjacent side walls 111, 112 (figures 8 and 9), near the entrance of the accommodation 110.

The entrance of the housing 110 corresponds to the open face of the housing 110 located as close as possible to the second end portion 220 of the leaf spring 200, which will be described in more detail later. As a variant, the contact element can be placed in the middle of the passageway for inserting the bare core of the electric cable, or in any place that ensures electrical contact between the contact element and the bare core of the electric cable.

In this case, a contact element 115 is provided in each of the two insertion passageways 107, 108 of the housing 110, and the bare core 4 of the electrical cable 2 therefore comes into contact with one of the two contact elements 115, regardless of the insertion passageway 107, 108 into which it is inserted.

As a variant, a plurality of contact elements can be provided in each insertion passageway of the housing.

Thus, in the second exemplary embodiment shown in FIGS. 17 and 18, two contact elements 115 are provided in each insertion passageway 107, 108 of housing 110. These contact elements are in this case positioned near the entrance and the outlet of the housing 110. With the exception of the number of contact elements arranged on the internal face of each insertion passageway, the connection element according to the second example of embodiment of figures 17 and 18 is totally similar to that of the first example of realization.

The peeled yam is then applied against at least one of the two contact elements 115 of the insertion passageway 107, 108 in which it is inserted.

Contact between the contact element and the bare core of the electric cable is then ensured, regardless of the direction in which the bare core is inserted into the insertion passageway. When the bare core of the electric cable is inserted parallel to the insertion direction E1 in the housing 110, the bare core 4 of the electric cable 2 is applied simultaneously against the two contact elements 115, which contributes to reducing the contact resistance of the set.

It may happen that the electrical cable is stressed in a direction orthogonal to the insertion direction E1. The bare core 4 of the electrical cable can then be placed in the housing in an inclined direction with respect to the insertion direction E1.

In this situation, the presence of two contact elements 115 makes it possible to ensure that the bare core 4 of the electric cable 2 is in contact with at least one of the two contact elements 115. For example, if the electric cable is pulled by the side of the receiving socket (on the left in figure 18), the bare core 4 of the electric cable remains in contact with the contact element 115 arranged near the outlet of the housing 110. If the electric cable is pulled from the opposite side to the receiving alveolus (on the right in figure 18), the bare core 4 of the electric cable remains in contact with the contact element 115 arranged near the entrance of the housing 110.

The contact between the contact element 115 and the bare core of the electrical cable is exerted in this case on a small area of the bare core due to the reduced dimensions of the contact element(s). Said second material preferably contains tin, silver, gold or another precious metal such as palladium, rhodium or platinum.

In practice, it is, for example, copper or tin-plated brass, that is, raw copper or brass coated with tin, a copper/tin alloy, tin, an alloy of metals containing gold, silver or other precious metal such as palladium, rhodium or platinum, or a metal such as brass plated with gold, silver or another precious metal such as palladium, rhodium or platinum.

Copper or brass can be plated with tin, gold, silver, for example, by electrolytic deposition, compaction, collamination or solder collamination method.

In general, the contact resistance that exists between the second material and the bare core of the electrical cable can be measured by any method known to those skilled in the art.

In this case, it is a matter of measuring the potential drop between the bare core of the electric cable 2 and the contact element 115 made of this second material, therefore on both sides of the contact interface, for the application of a given setpoint current. The contact resistance is deduced in this measurement.

The contact resistance can be measured in particular for the application of a reduced current, of the order, for example, from 10 to 100 milliamps, and/or for the application of the nominal current of the connection element 1, for example between 16 and 20 amps.

Preferably, the contact resistance between the second material and the bare core of the electric cable and the contact resistance between the first material and the bare core of the electric cable, measured for the same value of electric current intensity, will be compared.

The contact resistance can be measured under operating conditions of the connection element, that is to say in the chemical and mechanical environment of use and after a certain aging of the connection element. Preferably, the contact resistance between the second material and the bare core of the electric cable and the contact resistance between the first material and the bare core of the electric cable, measured for similar operating conditions, will be compared.

The contact resistance between the first material and the bare core of the electrical cable is measured, for example, in a contact element similar to that of the invention, but which does not comprise any contact element.

This contact resistance depends in particular on the characteristics of hardness, sensitivity to mechanical stress and resistance to chemical attacks of the material.

For example, with a relatively soft second material such as tin, oxides that can form on the surface of the contact element crack when the bare core of the electrical cable is applied against this contact element, which reduces the contact resistance. between the bare core of the electrical cable and the contact element.

More precisely, in this case, each contact element 115 belongs to a rivet 117 (see in particular figures 13 to 16).

The base wall 103 is thus equipped with two rivets 117 made of said second conductive material. In this case, these are rivets 117 made of tin.

Each rivet 117 is riveted to the base wall 103, through a hole 116 in this base wall 103 (FIG. 14). Each rivet 117 comprises two ends 115, 118 which extend projecting with respect to said base wall 103 (figures 15, 16 and 18).

The internal end 115 of the rivet 117 then extends, protruding from the wall 103, towards the interior of the housing 110 (figures 15, 16 and 18), and constitutes the contact element 115.

This contact element 115 then has, for example, a protruding thickness of the base wall 103 of between 0.3 and 0.4 millimeters.

According to an embodiment variant not shown here, the contact element belongs to a pad applied on said inner face of the base wall of the housing

This pad is welded, for example, on said internal face of the base wall at the place where the internal end 115 of the rivet 117 protrudes in the example of embodiment detailed in this case.

The two lateral walls 111, 112 of the housing 110 are extended by the two curved intermediate parts 121, 122 that approach each other, and then by the two curved walls 123, 124 that mutually delimit the alveolus 120.

This alveolus 120 generally has the shape of a cylindrical sleeve, the longitudinal axis of which extends along the direction of insertion I (FIGS. 1, 2, 5, 6 and 17).

The intermediate parts 121, 122 of the lateral wings 101, 102 join the edges of the main lateral walls 111, 112 to the curved walls 123, 124 of the alveolus 120.

Each intermediate part 121, 122 successively comprises, starting from the corresponding main side wall 111, 112, a fold 104 towards the inside of the connecting element 1, a curved part 121A, 122A towards the outside, and a flat part 121B, 122B. . The two flat parts 121B, 122B extend parallel to each other, close to each other (FIGS. 2, 5 and 8).

In this case, the fold 104 has a radius of curvature less than that of the curved part 121A, 122A (FIGS. 5, 6 and 9).

Each of the flat parts 121B, 122B is extended by one of the curved walls 123, 124 that partially form the alveolus 120. Each curved wall 123, 124 is curved towards the inside of the connecting element 1 and has, along the direction of insertion I, an end 123A, 124A that widens so as to facilitate the insertion of the connection pin in the socket 120 (figures 1, 2, 6, 8, 9 and 17).

It should be noted that in this case, the entrance of the housing 110 and the widened entrance of the alveolus 120 are arranged on either side of the connection element 1, imposing an opposite direction of insertion of the electrical cable and connection plug.

The spring blade 200 has the form shown in FIGS. 3, 7, 10 and 12 to 18. The spring blades 200 of the first and second embodiments are identical.

The spring blade 200 of the connecting element 1 according to the invention is made in one piece, by a metal band of which a first end portion 210 comprises a longitudinal slit 210A separating two branches 211, 212 adapted to tighten the curved walls 123, 124 of the socket 120 against the connection plug (not shown) and of which a second end portion 220 is adapted to press the bare core of the conductor cable inserted in the housing 110 against the base wall 103 and the contact element 115.

The first end portion 210 has a free end 201 and the second end portion 220 has a free end 202.

The spring leaf 200 has, in plan, a substantially rectangular contour, slightly tapered at its first free end 201, which extends along a longitudinal direction.

It comprises two elbowed parts 233, 234 around a first transverse axis T1 and a second transverse axis T2 parallel to T1. These two transverse axes T1, T2 are perpendicular to the longitudinal direction of the metal strip.

Viewed in profile, the spring leaf 200 thus has a globally S-shape (FIG. 12) with the first and second end portions 210, 220 extending respectively from one of said angled portions 234, 233 towards one of the ends. free parts 201, 202 of the spring leaf 200 and a central part 230 located between the two angled parts 233, 234.

These three parts 210, 220, 230 of the leaf spring 200 are flat.

The longitudinal slit 210A extends in this case in the plane of the spring leaf 200, along the first end portion 210 of one of the angled portions 234 and partially along the central portion 230 of the latter. spring leaf 200 (FIGS. 3 and 10).

The first end portion 210 of the leaf spring 200 is separated into two forward branches 211, 212 (FIGS. 3 and 10).

Said two front branches 211, 212 of the first end part 210 extend according to a median plane of the spring leaf 200 and are adapted to elastically separate from each other parallel to this median plane when the connection pin is inserted. on connection element 1.

On the other hand, in this case, the second end portion 220 of the spring leaf 200 is likewise separated into two rear branches 221, 222 by another longitudinal slit 240 (FIG. 10).

The free end of each of the two rear branches 221, 222 also includes a notch adapted to coincide with the contour of the bare core 4 of the electric cable 2 inserted in the housing 110 of the body 100 of the connection element 1 (figures 8 and 10). ).

In practice, the spring leaf 200 is housed in the body 100 in such a way that the second end part 220 and the third central part 230 of the spring leaf 200 are housed in the housing 110 of the body 100 (figures 1, 5). , 15, 16 and 18).

As shown in figures 1, 5, 8, 15, 16 and 18, the central part 230 of the spring leaf 200 is applied against a part of the inner face of each cambered part 121A, 122A of each intermediate part 121, 122 of each lateral wing 101, 102 of the body 100 of the connection element 1. It then extends substantially parallel to the insertion direction I of the connection pin in the socket 120.

The spring blade 200 has a width that is substantially the same, and may differ depending on the game, the width of the insertion space formed internally by the housing 110 of the body 100, with the exception of a central zone of the spring blade 200 that has a greater width since it has two tabs 231, 232 that extend locally from the edge of the spring leaf 200 (FIG. 3).

The spring blade 200 comprises, in fact, means for holding it in the housing 110, which cooperate in retention with complementary means of the body 100 of the connection element 1.

More precisely, in this case, the central part 230 of the spring leaf 200 comprises the two tabs 231, 232 which extend in the plane of this central part 230 of the spring leaf 200, towards the outside of the spring leaf. (figures 3, 7 and 10).

Each of these lugs 231, 232 is received in a window 109 of the body 100 of the connection element 1, located in this case at the level of the fold 104 that joins the curved part 121A, 122A of the intermediate part 121, 122 of each wing side wall 101, 102 to the corresponding side wall 111, 112 of the housing 110 (figures 1, 5 and 11). The spring leaf 200 is thus mounted by snapping onto the body 100 of the connecting element 1.

The shape of the lugs 231, 232 allows the maintenance of the spring blade 200 in the housing 110 when the bare core 4 of the electric cable 2 is inserted.

The second end part 220 of the spring leaf 200 extends through the housing 110, and the free end 202 of the second end part 220 of the spring leaf 200 rests against the internal face of the base wall 103 of the housing. 110 (FIG. 7) when no lead wire is inserted into the housing 110. In this case, moreover, the free end 202 of the second end portion 220 of the spring leaf 200 bears against the contact element 115 at rest.

The spring leaf 200 can be slightly prestressed so that this second end portion 220 of the spring leaf 200 permanently exerts pressure against the inner face of the base wall 103 of the housing 110 and/or on the contact element 115.

More precisely, as Figure 8 shows, the free end of each of the two rear branches 221, 222 of the second end portion 220 of the spring leaf 200 is shaped so as to be housed in one of the two passageways. insertion 107, 108 of the electrical cable.

The free end of each rear branch 221, 222 thus extends through one of the insertion corridors 107, 108, between one of the side walls 111, 112 of the housing 110 and the adjacent low wall 106, and is supported against the wall base 103 and/or the contact element 115 (figure 15) when the bare core 4 of the electric cable 2 is outside the housing 110 of the connection element 1.

As a variant, the spring leaf can be housed at rest in said housing. The free end of each trailing branch is not necessarily in contact with the base wall and/or the contact element prior to the introduction of the bare core of the electrical cable.

The first end portion 210 of the spring leaf 200 emerges outside the housing 110 and extends in the direction of the socket 120 (FIGS. 11 and 17).

This first end part 210 of the spring leaf 200 then extends substantially perpendicular to the insertion direction I of the connecting pin in the socket.

More precisely, in this case, the first end part 210 of the sheet 200 emerges near the widened end 123A, 124A of the bulged part 123, 124 of the lateral wing 101, 102 (FIGS. 11 and 17).

In addition, as shown in figures 1, 5 and 8, a part of the body 100 of the connecting element 1 extends in the longitudinal groove 210A, between the front branches 211, 212 of the spring leaf 200. It is in this case of a part of the flat part 121B, 122B of the intermediate part 121, 122 of each lateral wing 101, 102 of the body 100 of the connection element 1.

Indeed, as shown in figure 10, the height of each lateral wing 101, 102 of the body 100, measured according to the direction of insertion I of the connection plug, is lower at the level of the curved part 121A, 122A of the part intermediate part 121, 122 of this lateral wing 101, 102 than at the level of the flat part 121B, 122B of the intermediate part 121, 122.

This allows the first end portion 210 of the leaf spring 200 to emerge above the edges of the cambered portions 121A, 122A of the intermediate portions 121, 122, such that the free ends of the forward legs 211, 212 of the first end portion 210 of the spring leaf 200 frame the ends of the flat portions 121B, 122B of the intermediate portions 121, 122 of the lateral wings 101, 102 (FIGS. 1 and 5).

The spring blade 200 is thus adapted to cooperate with said wings of the body 100 so as to limit the separation of the curved portions 123, 124 of the lateral wings 101, 102 that delimit the alveolus 120.

In this case, in the standby position, when no pin is inserted in the receiving socket 120, the free ends of the front branches 211, 212 of the first end portion 210 of the spring leaf 200 are in contact with the flat parts 121B, 122B of the intermediate parts 121, 122 of the side wings 101, 102, without exerting any pressure on them.

As a variant, in the waiting position, the free ends of the front branches of the first end portion of the leaf spring may be out of contact with the ends of the flat portions of the intermediate portions of the side wings.

Also as a variant, in this waiting position, the free ends of the front branches of the first end part of the spring leaf can pinch the ends of the flat parts of the intermediate parts of the lateral wings.

The material of the spring sheet has satisfactory rigidity characteristics to perform its role of tightening the electric cable and the connection plug. It is not necessary that it be made of a conductive material, which makes it possible to limit the amount of conductive material used to manufacture the connection element according to the invention. The spring blade is made, for example, of steel, in particular of stainless steel. In practice, thanks to the connection element 1 according to the invention, the heating of the connection element 1 is limited when the electric current passes from the electric cable to the connection element. When the bare core 4 of the electrical cable 2 is inserted into the housing 110, the second end part 220 of the spring leaf 200 is adapted to bend slightly about the first transverse axis T1 to allow the introduction of this bare core into the housing. corresponding housing 110.

Thus, when the bare core 4 of an electrical cable 2 is inserted into the housing 110 along one of the insertion passageways 107, 108, the second end part 220 bends towards the central part 230 of the spring sheet 200 so as to free a passage for the bare core 4 of the electric cable in the corresponding insertion passageway (figure 16). When the bare core 4 of the electric cable 2 extends into the insertion passageway, the second end 220 of the spring leaf 200 tends to return to its unbent rest position, thus applying the bare core 4 of the electric cable 2 against the internal face of the base wall 103 of the housing 110 and against the contact element 115.

In this case, two electrical cables can be inserted in each connection element 1, in the two insertion passageways 107, 108 of the housing 110 described above.

In this case, each cable is inserted according to a direction perpendicular to the longitudinal axis X1 of the connection element 1 and parallel to the insertion direction I of the connection plug.

Each posterior branch 221, 222 is adapted to bend independently of the other posterior branch, to allow the insertion of the bare core 4 of the electrical cable 2 in one of the insertion passageways 107, 108, independently of the insertion of an electrical cable. in the other insertion corridor.

The free end 202 of the stressed rear branch 221, 222 then exerts pressure on the bare core of the electrical cable, so as to apply it against the contact element 115 and the base wall 103 of the housing 110.

In this way, the bare core 4 of the electrical cable 2 is applied against the contact element 115 made of the second material that has a reduced contact resistance with respect to the first material that constitutes the rest of the body of the electrical connection element 1.

The presence of this contact element 115 interposed between the bare core 4 of the electric cable 2 and the part of the body 100 made of the first material makes it possible to reduce the global contact resistance that exists between the bare core 4 of the electric cable 2 and the element of connection 1, and thus limit the heating of the assembly when the flow of current takes place.

The experimental results obtained by the applicant show, in fact, that the global resistance of the connection element according to the invention provided with tin rivets is similar to that of a connection element entirely made of tin-plated brass, without a contact element.

In addition, the contact element 115 has a reduced size with respect to the connection element 1, and requires a small amount of second material to be manufactured. Its installation in the connection element is simple. The connection element 1 according to the invention is therefore inexpensive.

The manufacturing cost of the connection element according to the invention is also limited, since the trimming waste of the material that forms the body of the connection element (copper or brass, for example), can be easily recycled and, therefore, They resell at a price close to the purchase price. On the contrary, if the body is made entirely of tin-plated brass, for example, this material is not only more expensive to buy, but it is also more difficult to recycle since the tin must be separated from the brass. The trim residues are then resold at a price much lower than the purchase price. Therefore, the connection element according to the invention is cheap to produce.

On the other hand, in the described example of the connection element, the electrical conduction and clamping functions of the connection plug and the electrical cable are decoupled.

The electrical conduction is ensured only by the body 100, while the spring blade 200 ensures the tightening of the connection plug in the connection socket 120 and of the electric cable in the housing 110.

In addition, the tightening of the connection plug and that of each electric cable is ensured independently.

In fact, when the connection pin is inserted into the socket, it engages in the socket in the direction of insertion I, from the widened end of the socket 120 towards the interior of the socket 120. In this way, the socket connection tends to separate the curved parts 123, 124 of the lateral wings 101, 102 from one another.

However, said separation immediately causes the separation of the flat parts 121B, 122B from the intermediate parts 121, 122 of the lateral wings 101, 102.

The separation of the flat parts 121B, 122B from the intermediate parts 121, 122 of the lateral wings 101, 102 is, for its part, largely limited by the action of the spring blade 200 on these flat parts 121B, 122B. of the intermediate parts 121, 122 of the lateral wings 101, 102.

In effect, this spacing tends to separate the front branches 211, 212 of the leaf spring 200 in the plane of the leaf spring 200. The leaf spring 200 is then stressed in a transverse direction.

The spring leaf 200 has a low elasticity in this transverse direction, and allows only a small separation of the flat parts 121B, 122B of the intermediate parts 121, 122 of the lateral wings 101, 102. Thus, when the insertion of the connecting pin into the socket, the forward branches 211, 212 of the leaf spring elastically separate, and then tend to return to their initial positions.

The spring blade 200 thus cooperates with said wings of the body 100; 300 so as to oppose the separation of the curved parts 123, 124 of the lateral wings 101, 102 that delimit the alveolus 120.

In other words, the spring blade 200, 400 cooperates with said wings of the body 100 to bring the curved portions 123, 124 of the lateral wings 101, 102 that delimit the alveolus 120 closer together.

The front branches 211, 212 of the leaf spring 200 draw back the flat parts 121B, 122B of the intermediate parts 121, 122 of the lateral wings 101, 102 towards each other, and with them the curved parts 123, 124 of the alveolus. , in order to bring said curved portions 123, 124 closer to each other.

In this way, the front branches 211, 212 of the spring leaf 200 ensure the tightening of the connecting pin against the curved parts 123, 124 of the alveolus.

The electrical connection of the electrical cable and the connection plug is thus effectively ensured.

The connection element according to the invention, as described above, can be realized in different ways.

In practice, in this case, the body 100 is made by folding a metallic strip of the first conductive material, for example raw brass.

Windows 109 are drilled in the side wings 101, 102 as well as the opening 105 and the holes 116 in the base wall 103. This is preferably done before the metal strip is folded back.

A rivet 117 can then be inserted into each hole 116 and fixed, and then finally the strap can be doubled. This is in particular the case when an automated assembly of the connecting element 1 takes place. As a variant, in particular when a manual assembly takes place, a maximum number of folds of the strap can be made first, that is to say those that will not interfere with the manual crimping, and then place the rivets 117 and finally finish folding the strap.

The rivet 117 may be preformed or formed from a wire or a profile of the second material directly on the connecting element. For example, a previously tinned cable with a square section of 1 millimeter on a side and 1.5 millimeters in length is used, crimped in the connection element.

As a variant, instead of drilling the holes and installing the rivets, two pads made of the second material are welded on the inner face of said base wall 103. This is preferably done before the metal strip is folded back.

In particular, it can be a connection element that has a single insertion passageway delimited by the housing, into which a single electrical cable can be inserted. In this single passageway, one or more contact elements are provided according to the invention.

It can also be a connection element with a different geometry, for example in which the space for inserting the electrical cable or cables in the housing extends in a direction perpendicular to the direction of insertion of the connection plug in the socket. Also, the spring leaf can have a different shape.

It can also be a simpler connection element, comprising only a housing and a spring blade, such as an automatic terminal, without a socket for receiving a connection plug. Lastly, the number of connecting elements and their shape can obviously vary.

Claims (13)

1. Electrical connection element (1) comprising a metallic conductive body (100) made of a first material and housing a spring blade (200), said spring blade (200) being adapted to apply against an internal face of a wall (103) of the body (100) the bare core (4) of a conductor cable (2) inserted in said connection element (1), characterized in that this internal face of the wall (103) of the body (100) is provided with a contact element (115) made of a second material different from the first material, against which said spring blade (200) is adapted to apply said bare core (4) of the conductor cable (2) when the latter is inserted into the connection element (1), said second material presenting a contact resistance with the bare core of the electric cable that is lower than the contact resistance between the first material and this bare core of the electric cable. 2. Electrical connection element (1) according to claim 1, wherein said second material contains tin, silver or gold. Electrical connection element (1) according to one of claims 1 and 2, in which said first material contains copper. Electrical connection element (1) according to one of the preceding claims, in which at least two contact elements made of the second material are provided and said spring blade (200) is adapted to apply the bare core (4 ) of the electric cable (2) against at least one of the two contact elements. Electrical connection element (1) according to one of claims 1 to 4, in which each contact element (115) extends protruding towards the interior of the body (100), with respect to the internal face of said wall. Electrical connection element (1) according to one of claims 1 to 5, in which each contact element (115) belongs to a rivet (117) fixed through said wall (103). Electrical connection element according to one of claims 1 to 5, in which each contact element belongs to a pad applied on said internal face of the wall. 8. Electrical connection element (1) according to one of claims 1 to 7, in which said body (100) comprises at least two insertion passageways (107, 108) adapted to guide the insertion of the stripped core (4) of the electrical cable (2) in the connection element (1), each one of the insertion corridors (107, 108) being delimited at least partially by said internal face of the wall (103) of the body, and being at least least one contact element (115) arranged in each insertion passageway (107, 108). Electrical switchgear comprising a connection element (1) according to one of the preceding claims, for the electrical connection of an electrical cable. 10. Electrical switchgear comprising a connection element (1) according to the preceding claim, constituting a current socket for the electrical connection of said electrical cable and a connection plug belonging to another electrical switchgear. 11. Process for manufacturing an electrical connection element (1) according to one of claims 1 to 8, comprising a metallic conductive body (100) made of a first material and housing a spring blade (200), said spring blade (200) adapted to apply against an internal face of a wall (103) of the body (100) the bare core (4) of a conductive cable (2) inserted in said electrical connection element (1), this being internal face of the wall (103) of the body (100) provided with a contact element (115) made of a second material that has a contact resistance with the bare core of the electrical cable lower than the contact resistance between the first material and this bare core of the electric cable, according to which said body (100) is cut out of the first material, and then the contact element (115) is fixed on the inner face of the wall (103) of this body (100). made in the second material. 12. Manufacturing method according to the preceding claim, according to which the contact element (115) is formed so that it belongs to a rivet (117), and a hole (116) is drilled in said wall (103) of the body ( 100), and said rivet (117) made of the second material is fixed thereto. Manufacturing method according to claim 11, according to which the contact element (115) is formed so that it belongs to a pad, and said pad made of the second material is welded to an internal face of said wall.