Patent Description:
For example, the invention can find an application in a power connector, such as those used to charge a rechargeable electric or hybrid vehicle battery.

Thus, for example, as represented schematically in <FIG>, the rechargeable electric or hybrid vehicles <NUM> can comprise a connector socket <NUM> to which can be connected a charge plug <NUM> powered by an electric charging station <NUM>, via a cable <NUM>. This charge plug <NUM> then makes it possible to charge a battery located in the vehicle <NUM>.

A charge plug <NUM> generally comprises power electrical contacts <NUM> for the charging of the vehicle (an example of power electrical contacts is described for example in the document <CIT>) and electrical contacts <NUM> intended to transmit an electrical signal (see for example the exploded view of the charge plug represented in <FIG>). The power electrical contacts <NUM> for the charging of the vehicle are female contacts. This electrical signal generally makes it possible to control the power supply of the charge plug <NUM>, in particular during connection and disconnection phases, so as to cut the power supply before the charge plug <NUM> is itself fully disconnected. It can however happen that, in rare circumstances, a charge plug <NUM> is disconnected while it is powered. In such circumstances, an electrical arc can occur between the power contacts <NUM> of the charge plug <NUM> and the power contacts of the socket <NUM>. It has been observed that such electrical arcs can damage, in particular, the power contacts <NUM> of the charge plug <NUM>. It is then desirable to avoid having the contact quality at the power contacts <NUM> being degraded if the charge plug is disconnected while it is powered (an example of a protection system is described in the document <CIT>). For example, it is desirable to ensure a constant contact quality even if the charge plug <NUM> undergoes at least fifty live disconnections.

In the field of power connection systems for motor vehicles, the female contacts for the charge plugs are generally machined by bar turning from a bar of conductive material, for example a copper alloy. Such a female contact comprises a bush comprising a plurality of elastic blades. Each elastic blade extends longitudinally, parallel to a central axis, between a base and a free end. The generation of an insertion force, of a contact force and of an electrical conduction suited to the application targeted is obtained in particular by the choice of the material and of the form of the blades (cross section, length, angle relative to the central axis, etc.). These blades are configured to receive the pin of a male contact between them when the latter is mated to the female contact. Each blade is thus configured to establish at least one electrical contact with the pin of the male contact. The male pin may be provided at its free end with a cap composed of dielectric material (see for example <CIT>). An example of opposite construction can be found in <CIT>, in which the pin comprises a plurality of elastic blades and the female contact is a one piece tube body.

<CIT> discloses a female contact provided with two bent contact zones forming a first and a second contact surfaces.

The applicant is faced by a problem of designing and producing a female contact that can retain a constant contact quality even if the charge plug undergoes at least fifty live disconnections.

The solution found consists in creating, on the female contacts, in the present case mounted in a charge plug, at least two contact zones: a sacrificial zone at which an electrical arc can occur and a useful contact zone which is preserved from any electrical arcs. More specifically, in order to ensure that no electrical arc can occur at a useful contact zone, each blade is provided with a sacrificial zone.

There is thus provided, according to the invention, a connection assembly comprising a male contact and a female contact. The male contact comprises a pin composed of an electrically conductive material. This pin extends longitudinally along a central axis parallel to a direction of insertion (during the coupling of the male contact with a female contact or when the latter are mated), between an end linked mechanically and electrically to a fixing portion, and a free end. The female contact comprises a bush comprising a plurality of elastic blades. Each elastic blade extends longitudinally, between a base and a free end, and is linked to the rest of the contact only at the base. The blades are configured to receive the pin of the male contact between them and establish at least one electrical contact with the pin, when the male contact is mated to the female contact.

Furthermore, each of the blades comprises two bent contact zones so as to form, respectively, on each of these bent zones, a first and a second contact surfaces that are convex and essentially oriented towards the central axis, the first contact surface being situated closer than the second contact surface to the free end of the blade on which they are formed. In other words, the first contact surface corresponds to a sacrificial zone and the second contact surface corresponds to a useful contact zone.

Furthermore, the pin is provided, at its free end, with a cap composed of a dielectric material. The first contact surface of each blade is then conformed so that, upon connection of the male contact and of the female contact, the first contact surface rests on the cap before establishing an electrical contact with an electrically conductive zone of the pin, wherein a length of the cap parallel to the direction of insertion is greater than or equal to the distance between the first and second contact surfaces parallel to this same direction.

This connection assembly possibly comprises one or other of the following features, considered independently of one another or in combination with one or more others:.

According to yet another aspect, the invention relates to a connection, disconnection and electrical power supply method for an assembly such as that mentioned above. This method comprises:.

Other features and advantages of the invention will become apparent on reading the following detailed description and from the attached drawings. In these drawings:.

An example of connection assembly according to the invention is represented in <FIG>. This assembly comprises a connector socket <NUM> and a charge plug <NUM>. Male power contacts <NUM> (not represented in <FIG>) are mounted in cells of the socket <NUM>. The male contacts <NUM> comprise a pin <NUM> composed of an electrically conductive material and extending longitudinally along a central axis C parallel to a direction of insertion, between an end linked mechanically and electrically to a fixing portion, and a free end. They are of a type known to the person skilled in the art. Power female contacts <NUM> are mounted in the charge plug <NUM>.

As represented in <FIG>, the charge plug <NUM> comprises a housing <NUM> (in the present case composed of several elements 303a) in which are housed, in a manner known to the person skilled in the art, female contacts <NUM>. As represented in <FIG>, the female contacts <NUM> comprise a fixing portion <NUM> and a connection portion <NUM>. The fixing portion <NUM> is intended to electrically and mechanically link the contact <NUM> to an electrical wire. The connection portion <NUM> is intended to receive a pin <NUM> of a male contact <NUM>.

The female contact <NUM> corresponding to the embodiment of <FIG>, is formed by cutting and stamping an electrically conductive material in sheet form. This material is composed for example of a copper alloy, in the form of a sheet whose thickness is between <NUM> and <NUM> millimetre, and is for example preferentially <NUM> millimetres.

This female contact <NUM> is designed to comply with the international standard IEC <NUM>. The latter defines the interface between the charge plug <NUM> and the socket <NUM>, the geometry of the cavities in which the contacts must be housed and the points at which the electrical conduction must be established between the male and female contacts.

Thus, for example, the female contact <NUM> must make it possible to maintain a heating temperature lower than <NUM> when, mated with a male contact <NUM>, it is passed through by an electrical current of <NUM> amperes. However, even if, for this purpose, a relatively thick sheet of electrically conductive material is used, the coupling effort between the female contact <NUM> and a male contact <NUM> must be less than <NUM> Newtons.

Furthermore, this female contact <NUM> must satisfy.

To these constraints is added the fact that the male <NUM> and female <NUM> contacts must comply with the IP2X standard, and possibly that the cost of production of the female contacts <NUM> be controlled, even reduced.

All this has been taken into account in designing the female contact <NUM> described hereinbelow.

The fixing portion <NUM> is designed to produce a fixing and connection by clamping with an electrical wire. In <FIG>, the fixing portion <NUM> is still linked to a support strip <NUM>.

After cutting and shaping, the female contact <NUM> has a connection portion <NUM> in the form of an essentially cylindrical bush. The bush is formed by bending and rolling the sheet of cut electrically conductive material. The connection portion <NUM> is linked mechanically to the fixing portion <NUM>. This bush comprises a base <NUM> and a plurality of elastic blades <NUM>. In the example represented, there are six of the elastic blades <NUM>, distributed essentially symmetrically about a central axis C, parallel to a direction of insertion of a pin <NUM> of a male contact <NUM> into the bush. Each elastic blade <NUM> extends longitudinally, between the base <NUM> and a free end <NUM>. Each elastic blade <NUM> is linked to the rest of the contact only at the base <NUM>. In other words, each blade <NUM> is separated from its nearest neighbours by a space <NUM> which extends between the base <NUM> and the free end <NUM> of the blades <NUM> and which mechanically and electrically insulates them from one another. Between the base <NUM> and the free end <NUM> of the blades <NUM>, the cross section of the blades <NUM> is essentially rectangular (see also <FIG>).

The base <NUM> essentially has a straight circular cylindrical form. The longitudinal edges <NUM> of the cutout at the base meet on a plane of symmetry P (cutting plane of <FIG>, see also <FIG>), passing also through two diametrically opposing gaps <NUM>. The blades <NUM> are distributed symmetrically on either side of this plane of symmetry P (three blades <NUM> on each side of the plane).

As represented in <FIG>, each elastic blade <NUM> comprises a first portion <NUM> situated in the extension of the base <NUM> and parallel to the generatrix of the cylinder of the base <NUM>. For example, this first portion <NUM> has a length of between <NUM> and <NUM> millimetres, and is for example preferentially <NUM> millimetres.

Each elastic blade <NUM> also comprises a second portion <NUM> situated in the extension of the first portion <NUM> towards the free end <NUM>. When it is not stressed, the second portion <NUM> forms, with the first portion <NUM> (that is to say also with the central axis C) an angle α of between <NUM> degrees and <NUM> degrees, and is for example preferentially <NUM> degrees. In other words, when the blades <NUM> are not stressed and they are considered from their second contact surface <NUM> to the base <NUM>, the blades form an acute angle α with the direction of insertion.

For example, this second portion <NUM> has a length of between <NUM> and <NUM> millimetres, and is for example preferentially <NUM> millimetres. The join between the first <NUM> and second <NUM> portions acts as hinge. In other words, when the pin <NUM> of a male contact <NUM> is inserted between the blades <NUM> of a female contact <NUM>, the length of the second portion <NUM> is such that the second portion <NUM> forms a lever which is deformed essentially at the join between the first <NUM> and second <NUM> portions. This lever makes it possible to control the insert effort.

Each elastic blade <NUM> also comprises a third portion <NUM> situated in the extension of the second portion <NUM> towards the free end <NUM>. The third portion <NUM> comprises two bent contact zones <NUM>. These bent zones <NUM> comprise, each respectively, on the inner face of the corresponding blade <NUM>, a first <NUM> and a second <NUM> contact surfaces.

The lever provided by the second portion <NUM> thus makes it possible to control the contact force at these first <NUM> and second <NUM> contact surfaces.

When a blade <NUM> is not stressed, the third portion <NUM> forms, with the direction of insertion, a general angle β of between <NUM> and <NUM> degrees, and is for example preferentially <NUM> degrees. In other words, when the blades <NUM> are not stressed and they are considered from their first contact surface <NUM> to their free end <NUM>, the blades form an acute angle β with the direction of insertion.

Each of these contact surfaces <NUM>, <NUM> is convex and essentially oriented towards the space of reception of the pin <NUM> of a male contact <NUM> between the blades <NUM>. In other words, the curvature of this surface is generally directed towards the central axis C. The first contact surface <NUM> corresponds to a sacrificial contact zone to which any electrical arc is wanted to be oriented and which can possibly be degraded. In other words, the contact resistance can increase at a point of contact between this first contact surface <NUM> and the pin <NUM> of a male contact <NUM>. The second contact surface <NUM> corresponds to a useful contact zone for which the contact quality is wanted to be preserved. In other words, there is a desire to avoid having the contact resistance increase at a point of contact between this second contact surface <NUM> and the pin <NUM> of a male contact <NUM>.

More specifically, each blade <NUM> is bent towards the central axis C at the join between the second <NUM> and third <NUM> portions, to form a useful contact zone (at the second contact surface <NUM>) which approaches the central axis C. Then, each blade <NUM> has an inclined surface relative to the direction of insertion intended to limit the insertion effort, while leaving sufficient length towards the free end <NUM> to produce a sacrificial contact zone. In continuing along each blade <NUM>, towards its free end <NUM>, each blade <NUM> is once again curved, towards the central axis C, over a zone <NUM> which corresponds therefore in cross section to a concave form relative to the reception space. This concave zone <NUM> extends to the sacrificial contact zone (at the first contact contact surface <NUM>) which has a curvature which corresponds in cross section to a convex form relative to the reception space. Finally, the sacrificial contact zone is extended towards the free end by a part <NUM> that is essentially rectilinear seen in cross section.

A second embodiment of a female contact according to the invention is represented in <FIG>. The latter also comprises a fixing portion and a connection portion, but only the second <NUM> and third <NUM> portions of the connection portion <NUM> are represented. Each blade <NUM> comprises, as for the preceding embodiment, a first <NUM> and a second <NUM> contact surfaces. The first contact surface <NUM> corresponds to a sacrificial contact zone and the second contact surface <NUM> corresponds to a useful contact zone.

In this embodiment, each blade <NUM> is curved away from the central axis C at the join between the second <NUM> and third <NUM> portions, in order to have, upon the insertion of the male contact <NUM> between the blades <NUM>, an inclined surface relative to the direction of insertion intended to limit the insertion effort, while leaving sufficient length towards the free end <NUM> to produce a sacrificial contact zone. Then, the blade is curved in the opposite direction (over a zone <NUM> which corresponds therefore in cross section to a concave form relative to the reception space). After this zone <NUM> having a concave curvature, in the direction of the free end <NUM> of the blades <NUM>, each blade <NUM> is continued by a straight portion <NUM> that is inclined towards the axis of insertion. This straight portion <NUM> is continued to the sacrificial contact zone (at the first contact surface <NUM>) which has a curvature which corresponds in cross section to a convex form relative to the reception space. Finally, the sacrificial contact zone is extended, in the direction of the free end <NUM>, by a part <NUM>, seen in cross section, that is essentially rectilinear moving away from the central axis. This rectilinear part <NUM> forms, relative to the direction of insertion, essentially the same angle as the portion following the useful contact zone. This angle is designed to limit the effort of insertion of the pin of the male contact between the blades.

This second embodiment of the female contact is used, in relation to <FIG>, to illustrate an example of connection and disconnection method according to the invention.

<FIG> (position equivalent to that of <FIG>): a male contact <NUM> is introduced between the blades <NUM>, into the reception space, at their free end <NUM>. The blades <NUM> are not yet stressed and only a part of the cap <NUM> made of electrically insulating material of the male contact <NUM> penetrates at the third portion <NUM>. The cap <NUM> has a tapered form and the first contact surface <NUM> rests on the outer surface (inclined relative to the direction of insertion) of the cap <NUM>.

<FIG> (position equivalent to that of <FIG>): the pin <NUM> of the male contact <NUM> is introduced even more between the blades <NUM>, in the reception space. The blades <NUM> are stressed and begin to be deformed. The first contact surface <NUM> rests on the conductive part of the pin <NUM>. The second contact surface <NUM> is located in line with the cap, but does not rest on it.

<FIG> (position equivalent to that of <FIG>): the pin <NUM> of the male contact <NUM> is introduced even more between the blades <NUM>, in the reception space. The first contact surface <NUM> rests on the conductive part of the pin <NUM>. The blades <NUM> are a little more stressed and deformed. The second contact surface <NUM> is located in line with the cap and rests on the inclined surface thereof.

<FIG>: the pin <NUM> of the male contact <NUM> is introduced between the blades <NUM>, in the reception space. The blades <NUM> are stressed and deformed to the maximum. The second contact surface <NUM> rests on the conductive pin <NUM>, while the first contact surface <NUM> no longer rests thereon. The connection assembly comprising the male contact <NUM> and the female contact <NUM> can be passed through by a current. The electrical contact is established between the second contact surface <NUM> and the conductive part of the pin <NUM>. The second contact surface <NUM> represents a useful contact surface safeguarded from any electrical arcs, at which the heating cannot exceed, for a given current, a limit that is predetermined by design.

<FIG>: on disconnection, the pin <NUM> of the male contact <NUM> leaves the reception space but, in this step, even though the second contact surface <NUM> is no longer in electrical contact with the conductive part of the pin <NUM>, the first contact surface <NUM> does still rest thereon. The second contact surface <NUM> is located in line with the cap and rests on the inclined surface thereof. An electrical arc cannot therefore occur because there is sufficient conduction at the first contact surface <NUM>.

<FIG>: the pin <NUM> of the male contact <NUM> is still in contact with the first contact surface <NUM>. The second contact surface <NUM> is located in line with the cap and no longer rests on the inclined surface thereof. An electrical arc cannot occur because there is sufficient conduction at the first contact surface <NUM>. There is therefore a respective position of the male <NUM> and female <NUM> contacts in which the first contact surface <NUM> is still in contact with the pin <NUM>, while the second contact surface <NUM> is no longer in contact with the pin <NUM> and is located in line with the cap <NUM>. In other words, the length of the cap parallel to the direction of insertion is greater than or equal to the distance between the first <NUM> and second <NUM> contact surfaces parallel to this same direction.

<FIG>: the first <NUM> and second <NUM> contact surfaces are no longer directly in electrical contact with the conductive part of the pin <NUM>. If an electrical arc occurs, it will be established between the first contact surface <NUM> and the conductive part of the pin <NUM> since they correspond to the conductive zones closest to one another.

Claim 1:
Connection assembly comprising a male contact (<NUM>) and a female contact (<NUM>);
- the male contact (<NUM>) comprising a pin (<NUM>) composed of an electrically conductive material and extending longitudinally along a central axis (C) parallel to a direction of insertion, between an end linked mechanically and electrically to a fixing portion, and a free end,
- the female contact (<NUM>) comprising a bush comprising a plurality of elastic blades (<NUM>), each blade (<NUM>) extending longitudinally, between a base (<NUM>) and a free end (<NUM>), and being linked to the rest of the contact (<NUM>) only at the base (<NUM>), these blades (<NUM>) being configured to receive the pin (<NUM>) of the male contact (<NUM>) between them and to establish at least one electrical contact with the pin (<NUM>), when the male contact (<NUM>) is mated to the female contact (<NUM>);
in which the pin (<NUM>) is provided at its free end with a cap (<NUM>) composed of a dielectric material,
wherein
each of these blades (<NUM>) comprises two bent contact zones to form, respectively, on each of these bent contact zones, a first (<NUM>) and a second (<NUM>) contact surfaces that are convex and essentially oriented towards the central axis (C), the first contact surface (<NUM>) being situated closer than the second contact surface (<NUM>) to the free end (<NUM>) of the blade <NUM> on which they are formed characteried
in that the first contact surface (<NUM>) of each blade (<NUM>) is conformed so that, upon the connection of the male contact (<NUM>) and of the female contact (<NUM>), the first contact surface (<NUM>) rests on the cap (<NUM>) before establishing an electrical contact with an electrically conductive zone of the pin (<NUM>), wherein a length of the cap (<NUM>) parallel to the direction of insertion is greater than or equal to the distance between the first (<NUM>) and second (<NUM>) contact surfaces parallel to this same direction.