FR3085237A1 - METHOD FOR WIRING AN ELECTRICAL CONTACT, TOOL FOR IMPLEMENTING THIS METHOD AND ELECTRICAL CONTACT. - Google Patents

Abstract

The invention relates to a method of wiring an electrical contact (1) to an electrical wire (6), in which before, or during, the heating step, a force is applied at one end (14 ) a sleeve (12) formed of a portion of heat-shrinkable sheath, so that this end (14) is deformed during the heating step to establish, beyond the end of the wire (6), a sealing with the contact surface (1). The invention also relates to a tool (16) for implementing this method, as well as an electrical contact (1), for example obtained using the method and the tool (16) in accordance with invention.

Description

Method of wiring an electrical contact, tool for implementing this method and electrical contact.

The invention relates to the field of connectors, and in particular that of automotive connectors. In particular, the invention relates to the methods and tools used when wiring an electrical contact. The invention also relates to a wired electrical contact.

For some applications, electrical contacts may be exposed to moisture or other forms of contaminants. This is particularly the case for contacts for charging sockets for electric or rechargeable hybrid vehicles. These charge sockets are in fact mounted at the end of a cable intended to connect one of these vehicles to a charging station. Charging stations, vehicles and therefore also charging sockets can be exposed to the weather during charging.

Thus it is desirable to avoid, or at least limit any form of deterioration in the quality of the electrical contact between the conductive core of an electrical wire constituting the cable and the contact itself. Indeed, in particular on the power contacts, given the relatively high intensities of the charging currents, any degradation of this type could cause overheating with more or less serious consequences.

To this end, we have already thought of isolating from moisture the portion of the electric wire mechanically and electrically connected to the contact, and which is no longer protected by an insulating sheath, by adding more or less complex seals upstream and / or downstream of this portion, by adding a coating or filling material (“potting compound” in English), etc. The different solutions implemented in the prior art have a number of drawbacks such as cost, complexity of the process used, insufficient efficiency, etc.

The aim of the invention is to propose an alternative solution to the existing solutions.

To this end, there is proposed according to the invention a method of wiring an electrical contact with an electrical wire comprising an insulating sheath and a conductive core. The electrical contact comprises a connection portion and a fixing portion. The fixing portion has in particular an internal surface and an external surface. One end of the electric fd is connected to the fixing portion of the contact. This end of the electric wire is at least partially devoid of insulating sheath. This end is therefore stripped and brought into contact with the internal surface of the fixing portion.

This process includes several steps.

Thus, it comprises a fixing step consisting in mechanically and electrically connecting one end of the electric wire at least partially devoid of insulating sheath and in contact with the internal surface.

The method also includes a protective step consisting in covering the fixing portion with a sleeve made up of a tube portion made of heat-shrinkable insulating material; the sleeve then extends longitudinally essentially between a first end, located overlapping the insulating sheath, and a second end, located towards the connection portion of the contact; the sleeve also extends, towards the connection portion of the contact, at its second end, beyond the portion of the electric wire at least partially devoid of insulating sheath.

The method also includes a heating step consisting in heating at least a portion of the sleeve disposed on the fixing portion and on the portion of the electric wire at least partially devoid of insulating sheath.

Before, or during, the heating step, a force is applied at the second end of the sleeve to move the zone of the sleeve extending beyond the portion of the electric wire devoid of insulating sheath towards the internal surface. of the fixing portion.

Thanks to this process, the area of the sleeve on which the force is applied is deformed and during heating this area is pressed against the internal and external surfaces of the contact to establish, beyond the end of the wire, a seal. with these.

The method according to the invention may also include one or other of the following characteristics, considered in isolation or in combination with one or more others:

- the force applied at the second end of the sleeve reverses the curvature of the sleeve at least on the area on which the force is applied;

- which the heating step is carried out only after the force applied at the second end of the sleeve has displaced the area of the sleeve towards the internal surface of the fixing portion.

According to another aspect, the invention is a tool for implementing the method according to the invention. This tool includes a template and a finger. The tool is configured so that, once the contact is positioned on the template (or equivalently, in the template, if the template has, for example, a cage shape into which the contact can be inserted) finger is located at the area to be deformed, that is to say at the area of the second end of the sleeve, located beyond the portion of the electric wire at least partially devoid of insulating sheath. The finger is configured to be moved essentially toward the inner surface of the sleeve (for example, perpendicular to the longitudinal direction of the sleeve). In this movement, it deforms the area of the sleeve to be deformed, in the direction of the internal surface of the fixing portion.

The tool according to the invention may also include one or other of the following characteristics, considered in isolation or in combination with one or more others:

- The finger is configured to be moved between a rest position allowing the positioning of the contact on the template and a holding position in which one end of the finger maintains the area of the sleeve to be deformed towards or on the internal surface; and

- The finger has a shape complementary to that of the internal surface on which, or towards which, it maintains the area of the sleeve to be deformed.

In yet another aspect, the invention is a wired electrical contact. This comprises a connection portion and a fixing portion. The attachment portion has an inner surface and an outer surface. The fixing portion of this contact is mechanically and electrically connected to one end of an electric wire. This electrical wire comprises an insulating sheath and a conductive core. The end of the electric wire connected to the fixing portion of the contact is at least partially devoid of insulating sheath and is placed in contact with the internal surface of the fixing portion. The contact further comprises a sleeve made up of a portion of tube made of heat-shrinkable insulating material. This sleeve extends, along a longitudinal direction, essentially between a first end, located overlapping the insulating sheath, and a second end located towards the connection portion of the contact.

More particularly, the sleeve extends, towards the connection portion of the contact, at the second end, beyond the portion of the electrical fd at least partially devoid of insulating sheath.

The sleeve is in contact with the internal and external surfaces along a virtual line which would correspond to the intersection of these internal and external surfaces with a cutting plane essentially transverse to the longitudinal direction of the sleeve, this plane being located in the direction of the connection portion, beyond the portion of the electric wire at least partially devoid of insulating sheath.

The wired contact according to the invention may also include one or other of the following characteristics, considered in isolation or in combination with one or more others:

- the internal and external surfaces, at the level of the virtual line are respectively concave and convex

- the contact is made by cutting and stamping a conductive plate material; and

- the electric wire (is mechanically and electrically connected to the fixing portion by crimping.

Other characteristics and advantages of the invention will appear on reading the detailed description which follows as well as in the accompanying drawings. In these drawings:

- Figure 1 shows schematically in perspective an example of contact intended for the implementation of the method according to the invention it being still connected to a carrier strip,

FIG. 2 schematically represents in perspective a portion of the contact of FIG. 1, the latter being separated from its carrier strip,

FIG. 3 schematically represents in perspective the contact of FIGS. 1 and 2, with its fixing portion crimped on the stripped end of an electric wire,

FIG. 4 schematically represents, seen from the side, part of the contact of the preceding figures, with a heat-shrinkable sleeve positioned on its fixing part,

FIGS. 5 and 6 schematically represent the operation of deformation of the sleeve shown in FIG. 4, with a deformation finger respectively in a rest position and a holding position,

FIGS. 7 and 8 schematically represent in perspective the result of the deformation and heating operations of the sleeve shown in FIGS. 4 to 6,

- Figures 9 and 10 schematically show in perspective the contact of the previous figures respectively before and after its introduction into an example of a tool for implementing the method according to the invention.

In the different figures, similar or identical elements have the same references.

An example of contact 1 for implementing the method according to the invention is shown in FIG. 1. It is a female type contact, but the invention can also be implemented with a contact of male type. This contact 1 is a power contact, but the invention can also be implemented with a signal contact.

This contact 1 is made by cutting and stamping a conductive material in a plate, but the invention can be implemented on a contact made by other methods.

This contact 1 is also connected to a carrier strip 2. This contact 1 comprises a connection portion 3, a fixing portion 4 and an intermediate portion 5, located between the connection portion 3 and the fixing portion 4. The portion of fixing 4 is, for the example described here, suitable for connecting mechanically and electrically, by crimping, the contact 1 at the end of an electric wire 6. It will be noted that the invention is not limited to a setting implemented on a contact 1 provided with a fixing portion 4 by crimping. Indeed, the invention can also be used, for example, when the contact is provided with a fixing portion 4 adapted to a solder connection, from the end of the electric wire 6 to the contact 1.

The fixing portion 4 comprises two crimping fins 7 extending from a groove 8 extending along a longitudinal direction L corresponding, in the example presented here, to the longitudinal direction of the contact

1. The groove 8 continues, in the direction of the connection portion 3, up to the intermediate portion 5. At the level of the groove 8, the fixing portion 4 thus comprises, an external surface 9 convex and an internal surface 10 concave.

As can be seen in Figure 3, after crimping, the fins 7 are folded over one end of the electric wire 6 devoid of insulating sheath 11 (at the crimping area, there is essentially only the core of the electric wire 6). In other words, the end of the electric wire 6 connected to the fixing portion 4 is devoid of insulating sheath 11 and is in contact with the internal surface 10 of the groove 8. In the direction of the connection portion 3, the end of the electric wire 6 protrudes from fins 7 over a length 1.

According to the method according to the invention, a sleeve 12 is placed on the fixing portion 4. It covers part of the insulating sheath 11. It extends parallel to the longitudinal direction L between a first end 13 and a second end 14 The first end 13 is located overlapping the insulating sheath 11. The second end 14 is located towards the connection portion 3. The sleeve 12 extends at the level of the second end 14, beyond the end of the electric wire 6 which protrudes from the fins 7. In other words, it exceeds the edge 15 of the fins 7 located on the side of the connection portion 3, with a length D greater than 1 (see FIG. 5).

This sleeve 12 consists of a portion of tube made of heat-shrinkable insulating material. It is for example a polyolefin tube. The tube forming the sleeve 12 has for example a diameter of 12mm, for an electric wire 6 of 6mm ² .

In accordance with the method according to the invention, the sleeve 12 can first be threaded onto the electric wire 6 before the fixing operation consisting in mechanically and electrically connecting the end of the electric wire 6 to the fixing portion 4. Alternatively, if the internal diameter of the tube is sufficient, the sleeve 12 is threaded onto the contact 1 after this operation of fixing the electric wire 6 to the contact 1.

According to the method according to the invention, an area of the sleeve 11 located at the second end 14 of the sleeve 11 is deformed using a tool 16. This tool 16 has a finger 17 which can be moved between a position rest (which can correspond for example to its position in Figure 5) and a holding position (which can correspond for example to its position in Figure 6). In the holding position, the finger 17 presses the region of the sleeve 11 which partly extends beyond the end of the electric wire 6, to move it towards the internal surface 10 of the fixing portion 4.

Once the finger 17 in the holding position, the sleeve 12 is heated. It then retracts on the fixing portion 4 and tightens in particular on the one hand on the insulating sheath 11 and on the other around the groove 8, on the external 9 and internal 10 surfaces, beyond the portion of the wire electric 6 coming out of the crimping fins 7.

Thus, if a section is made of the fixing portion 4, at a transverse plane P essentially perpendicular to the longitudinal direction L of the contact 1, the internal 10 and external 9 surfaces form a continuous line (see dotted lines on the Figure 8) on this plane P. The sleeve 12 is in contact with the internal 10 and external 9 surfaces along this line, thus providing a seal between the contact 1 and the sleeve 12. The volume, inside the sleeve 12 , lying between, on the one hand, the zone of overlap of the insulating sheath 11 by the sleeve 12 and, on the other hand, this line corresponds to a sealed zone which is thus isolated from humidity and possible other sources of contamination. The part of the electric wire 6, stripped, being taken in the crimping fins 7, like the part of this electric wire 6 which extends beyond the fins 7 in the direction of the connection portion 3 are enclosed in the sleeve 12. This avoids, or at least limits, a deterioration of the electrical contact between the electric wire 6, on the one hand, and the internal surfaces of the fins 7 and of the groove 8, on the other hand.

FIGS. 9 and 10 show a prototype tool 16 suitable for implementing the method described above. This prototype is designed for manual use, but those skilled in the art can, without showing inventive activity, adapt this tool 16 to integrate it into an automated production chain. This tool 16 includes in particular a cage 18 whose dimensions are adapted to form a template. Thus, the connection portion 3, the end of the electric wire 6 on which the contact 1 is crimped and the sleeve 12 are introduced into the cage, until the coupling end 19 of the contact 1 comes into abutment against the bottom of the cage 18. The contact 1 is introduced into the cage 18 by orienting the open groove 8 on the top (towards a person who looks at the figure perpendicular to the sheet on which the figure 9 is shown). The finger 17 is then lowered onto the end of the sleeve 12, and more particularly onto the region of the sleeve 12 which protrudes beyond the electric wire 6. The finger 17 has a shape complementary to that of the internal surface 10 on which, or towards which it maintains the area of the sleeve 12 to be deformed. In the example shown in Figures 5, 6 and 10, the free end of the finger 17 coming into contact with the sleeve 12 has the shape of a half-cylinder adapted to engage in a complementary manner with the groove 8. The effort applied by the free end of the finger 17 in contact with the sleeve 12, reverses the curvature of the sleeve 12 at least on the area on which the force is applied. In this area, the sleeve 12 no longer has the shape of a cylindrical tube of revolution, but a shape of a gutter. The finger 17 is held in this position while the sleeve 12 is heated to obtain its retraction on the fixing portion 4.

Alternatively, once the curvature of the sleeve 12 is reversed by the pressure exerted by the finger 17, the deformation of the sleeve 12 can remain frozen even if the finger 17 returns to its rest position. Thus, even without finger pressure 17 on the sleeve 12, the retraction of the sleeve 12 takes place while retaining this deformation and the sleeve 12 retracts around the internal 10 and external 9 surfaces, at the level of the fixing portion 4 located at the beyond the free end of the electric wire 6, to obtain a result such as that presented in FIGS. 7 and 8.

Claims (9)

1. A method of wiring an electrical contact (1), this electrical contact (1) comprising a connection portion (3) and a fixing portion (4) having an internal surface (10) and an external surface (9) , this process comprising a fixing step consisting in mechanically and electrically connecting one end of an electric wire (6) to the fixing portion (4) of the contact (1), this electric wire (6) comprising an insulating sheath (11) and a conductive core, the end of the electric wire (6) connected to the fixing portion (4) of the contact (1) being at least partially devoid of insulating sheath (11) and in contact with the internal surface (10), a protection step consisting in covering the fixing portion (4) with a sleeve (12) consisting of a tube portion made of heat-shrinkable insulating material, this sleeve (12) extending longitudinally essentially between a first end ( 13), located overlapping the insulating sheath (11), and a second end (14) located towards the connection portion (3) of the contact (1), a heating step consisting in heating at least a portion of the sleeve (12) disposed on the fixing portion (4) and on the portion of the electric wire (6) at least partially devoid of insulating sheath (11), characterized by the fact that the sleeve (12) extends, towards the connection portion (3) of the contact (1), at the second end (14), beyond the portion of the electric wire (6) at least partially devoid of insulating sheath (11), and in that before, or during, the heating step a force is applied at the second end (14) of the sleeve (12) to move the area of the sleeve (12) extending beyond the portion of the electric wire (6) devoid of insulating sheath (11) towards the internal surface (10) of the fixing portion (4). 2. Method according to claim 1, in which the force applied at the second end (14) of the sleeve (12) reverses the curvature of the sleeve (12) at least over the zone to which the force is applied. 3. The method of claim 1 or 2, wherein the heating step is performed only after the force applied at the second end (14) of the sleeve (12) has moved the area of the sleeve (12) towards the internal surface (10) of the fixing portion (4). 4. Tool for implementing the method according to one of the preceding claims, comprising a template (18) and a finger (17), this tool (16) being configured so that, once the contact (1) positioned on the template (18), the finger (17) is located at a region to be deformed of the second end (14) of the sleeve (12), located beyond the portion of the electric wire (6) at least partially devoid of insulating sheath (11), the finger (17) being configured to be moved towards the internal surface (10) of the fixing portion, and to deform the area of the sleeve to be deformed, in the direction of the internal surface (10) of the fixing portion (4). 5. Tool according to claim 4, wherein - the finger (17) is configured to be moved between a rest position allowing the positioning of the contact (1) on the template and a holding position in which one end of the finger (17) maintains the area of the sleeve (12) at deform towards or on the internal surface (10) and - The finger (17) has a shape complementary to that of the internal surface (10) on which, or towards which, it maintains the area of the sleeve (12) to be deformed. 6. Wired electrical contact comprising a connection portion (3) and a fixing portion (4) having an internal surface (10) and an external surface (9), the fixing portion (4) of this contact (1) being mechanically and electrically connected to one end of an electric wire (6), this electric wire (6) comprising an insulating sheath (11) and a conductive core, the end of the electric wire (6) connected to the fixing portion ( 4) of the contact (1) being at least partially devoid of insulating sheath (11) and in contact with the internal surface (10), the contact (1) further comprises a sleeve (12) consisting of a portion of tube in heat-shrinkable insulating material extending, along a longitudinal direction (L), essentially between a first end (13), located overlapping the insulating sheath (11), and a second end (14) located towards the portion of connection (4) of contact (1), characterized by the fact that q ue the sleeve (12) extends at the second end (14), beyond the portion of the electrical fd (6) at least partially devoid of insulating sheath (11), and by the fact that the sleeve ( 12) is in contact with the internal (10) and external (9) surfaces along a virtual line which would correspond to the intersection of these internal (10) and external (9) surfaces with a plane (P) of section essentially transverse to the longitudinal direction (L) of the sleeve (12) and located, in the direction of the connection portion (3), beyond the portion of the electrical fd (6) at least partially devoid of insulating sheath (H) · 7. Wired contact according to claim 6, in which the internal (10) and external (9) surfaces, at the level of the virtual line are respectively concave and convex. 8. Wired contact according to claim 6 or 7, produced by cutting and stamping a conductive plate material. 9. Wired contact according to one of claims 6 to 8, in which the electric fd (6) is mechanically and electrically connected to the fixing portion (4) by crimping.