FR3092939A1 - Female contact with low insertion coefficient - Google Patents

Abstract

The invention relates to a female contact for a connector, a connection assembly comprising such a female contact, as well as a method of manufacturing this contact. This contact comprises a contact portion intended to receive a pin of a male contact. In order to reduce the effort of inserting the pin into the contact portion, the contact portion comprises a friction zone (14) with one or more relief structures (15). These structures in relief (15) make it possible to reduce the respective friction surfaces of the male and female contacts interacting with each other during their coupling. Figure to be published with abstract: Fig 5

Description

Female contact with low insertion coefficient

The invention relates to the field of connectors. For example, the invention finds an application in the field of automotive connectors.

State of the art

In general, and in particular in the automotive field, there is a need to connect more and more electrical or electronic devices to each other. To this end, electrical circuits are designed comprising more and more connectors, these connectors themselves comprising more and more contacts. This then leads to possible musculoskeletal disorders among the operators in charge of mounting and assembling these electrical circuits. A well-known solution to avoid, or at least reduce, the risk of musculoskeletal disorders is to provide a mating aid lever on the connectors. But this solution has some drawbacks. In particular, equipping a connector with a lever increases its manufacturing cost, generates additional consumption of plastic material and leads to the production of bulkier connectors requiring more space to be handled.

An object of the invention is to reduce, at least partially, all or part of these drawbacks.

To this end, a female contact for a connector has been developed comprising a fixing portion and a contact portion. The fixing portion is intended for the mechanical and electrical connection with contact, a cable or an electrical circuit. The contact portion is intended to receive a pin of a male contact, this pin being inserted into the contact portion essentially parallel to an insertion or mating direction. Furthermore, the contact portion comprises at least one flexible elastic blade. This blade extends longitudinally from a free end towards the connection portion. This blade has at least one contact surface intended to establish electrical contact with the pin of the male contact. This blade also has a friction zone located between the free end and the contact surface. This friction zone corresponding to a part of the blade with which the pin of the male contact interacts mechanically during an initial phase of the insertion of the pin in the contact portion, before the pin interacts with the surface of contact. The friction zone is curved to form a non-zero insertion angle with the direction of insertion, in order to facilitate the guiding and insertion of the pin of the male contact into the contact portion.

Advantageously, the friction zone has a base surface with at least one structure in relief relative to this base surface. This structure in relief may include one or more recessed or projecting regions with respect to the base surface of the friction zone.

Thus, thanks to this characteristic, it is possible to reduce the respective surfaces of the male and female contacts brought to rub against each other, during the initial phase of the coupling of these male and female contacts, before the pin of the male contact does not reach the level of the contact surface provided on the blade of the contact to ensure electrical conduction between male and female contacts. By reducing the surfaces rubbing against each other, we contribute to the reduction of the friction forces and thus to the reduction of the insertion and coupling forces. One can then optionally no longer have to use a lever to facilitate the coupling of a male connector with a female connector provided with contacts having the characteristic mentioned above.

The female contact according to the invention optionally comprises one and/or the other of the following characteristics, each considered separately, independently of one another, or in combination of one or more others:

- the friction zone comprises several structures in relief, each of the structures in relief extending over an area of the friction zone, the sum of the areas over each of which a structure in relief extends, is less than the area of the friction zone on which the structures in relief are distributed;

- the friction zone comprises at least one structure in relief, this structure in relief or all the structures in relief occupying a region of the friction zone, and the surface of the friction zone on which the friction zone and a male contact pin are intended to interact, is less than the area delimited by the peripheral limit of the region of the friction zone occupied by the structure or structures in relief;

- at least one structure in relief forms a protuberance projecting with respect to the base surface of the friction zone;

- at least one structure in relief forms a hollow with respect to the base surface of the friction zone; and

- the friction zone corresponds to a part of the blade having a section perpendicular to the essentially straight direction of insertion.

According to another aspect, the invention relates to a connection assembly comprising a male connector and a female connector, in which the female connector comprises at least one female contact according to the invention and the male connector comprises at least one male contact with a pin having at least one contact surface interacting with the contact surface of the female contact.

In this connection assembly, the pin of the male contact has, at its free end, friction surfaces inclined with respect to the direction of insertion.

According to another aspect, the invention relates to a method of manufacturing a female contact, in which a conductive metal sheet is provided, with two main faces. The sheet is cut and folded to form in particular a contact portion of a female contact. This contact portion comprises, after manufacture of the contact, at least one contact blade with a free end, at least one contact surface, and a friction zone located between the free end and the contact surface. The method also comprises at least one operation during which the state of the surface of the main face of the sheet also corresponding to the contact surface is modified, on a zone intended to form the friction zone.

Optionally, the operation of modifying the state of the surface on the friction zone comprises at least one operation chosen from a list comprising the cutting, the engraving and the plastic deformation of the sheet.

Other characteristics, objects and advantages of the invention will appear on reading the detailed description which follows, and with regard to the appended drawings, given by way of non-limiting example and in which:

schematically shows in perspective an exemplary embodiment of a connection assembly comprising a female contact according to the invention, as well as a male contact;

schematically shows in perspective a portion of two contact blades of a female contact such as that shown in Figure 1;

schematically represents in longitudinal section a portion of two contact blades of a female contact such as that represented in FIG. 1, a pin of a male contact being presented, with a view to its insertion between these two blades, at the level of the zones friction thereof;

schematically represents in perspective friction zones corresponding to two examples of embodiments of a female contact according to the invention;

schematically represents in perspective friction zones corresponding to two other examples of embodiments of a female contact according to the invention;

schematically shows in longitudinal section the friction zone of a female contact blade of one of the embodiments shown in Figure 5;

schematically represents in perspective friction zones corresponding to two other examples of embodiments of a female contact according to the invention;

schematically represents in perspective friction zones corresponding to two other examples of embodiments of a female contact according to the invention; and

corresponds to an example of a diagram representing the insertion force as a function of the displacement of the pin of a male contact during its insertion between the contact blades, respectively of a standard female contact and of a female contact according to invention.

detailed description

According to one embodiment of the invention, this is a connection assembly comprising a male connector and a female connector. These may correspond to connectors of the prior art and will not be represented or described in detail in this document. Each of them comprises, in known manner, a casing made of dielectric material provided with cavities for respectively housing male contacts in the male connector and female contacts in the female connector.

An example of male contact 1 and female contact 2 is shown in FIG. 1. These male 1 and female 2 contacts extend essentially longitudinally parallel to an insertion direction I, during mating and after mating of the male connectors and female. These male 1 and female 2 contacts are made from one or more conductive metal sheets, for example of copper, aluminum or other alloy. Each sheet has two main sides. Each sheet is cut, deformed and folded to form a male 1 or female 2 contact. These male 1 and female 2 contacts each comprise a fixing portion 3 and a contact portion 4 respectively.

In the example described here, the fixing portion 3 is intended for the mechanical and electrical connection of contact 1 or 2 with a cable. The fixing portion 3 corresponds in the example illustrated by FIG. 1 to a crimping zone. But, according to variants, the fixing portion 3 of the male contact 1 and/or of the female contact 2 can equally well correspond to means of mechanical and electrical connection to an electrical or electronic circuit. These are then, for example, solder tabs and/or tabs to be inserted into printed circuit holes.

The contact portion 4 of the male contact 1 comprises a pin 5 extending longitudinally from the fixing portion 3 towards a free end 6. The cross section of the pin 5 is essentially constant except at the level of the free end 6 where it tapers to a point. On its part having a constant cross-section, pin 5 has two contact surfaces 7. On its tip part, the pin has two friction surfaces 8 (see FIG. 3). These friction surfaces 8 are inclined with respect to the direction of insertion I.

The contact portion 4 of the female contact 2 comprises a cage 9, in which are housed two contact blades 10 (shown in particular in FIGS. 2 and 3). These contact blades 10 are elastically deformable. These contact blades 10 extend longitudinally from the fixing portion 3 towards a free end 11. The contact blades 10 each comprise in particular a contact surface 12 and a friction zone 14. On each blade, the contact surface 12 and the friction zone 14 are continuous with each other on the same main face of the sheet in which the contact blade 10 is made. From the fixing portion 3, in the direction of the free end 11, the two contact blades 10 approach each other, towards a central axis C, parallel to the direction of insertion I, up to the contact surfaces 12. The contact surfaces 12 are opposite each other on either side of a plane of symmetry (perpendicular to the sheet in FIG. 3) passing through the central axis C. From the contact surfaces 12 in the direction of the free ends 11, the contact blades 10 deviate from each other, to form a "V", or even a funnel adapted to guide the spindle 5 towards the contact surfaces 12 and to facilitate the separation of the contact blades 10, during the insertion of the pin 5 in the contact portion 4 of the female contact 2, during the coupling of the male and female connectors. From the contact surfaces 12 in the direction of the free ends 11, the contact blades 10 therefore comprise friction zones 14 intended to interact mechanically with the friction surfaces 8 of the spindle 5 during the insertion of the spindle 5 into the contact portion 4 of female contact 2.

The male 1 and female 2 contacts are for example formed from a tinned copper alloy at least at the level of the contact surfaces 7, 12. Optionally, the friction surfaces 8 of the male contact 1, as well as the friction zones 14 of the female contact 2 are therefore also tinned.

The friction zone 14 of each contact blade 10 is therefore curved and deviates from the central axis C from the contact surface 12 towards the free end 11, to form a non-zero insertion angle α with the central axis C. For example, this angle α is between 20 and 60 degrees.

The friction zone 14 of one or more contact blades 10 comprises one or more structures in relief 15. Different variants of these structures in relief 15 are represented in FIGS. 4 to 8. The friction zones 14 represented in FIGS. to 8 correspond to a part of the contact blade 10 whose section, in a plane perpendicular to the central axis C, is essentially straight. But according to variants not shown, this section of the contact blade 10 could also be curved so as to deviate from the plane of symmetry between the two contact blades 10, away from the central axis C towards the edges of each contact blade 10.

As shown in Figure 4, a friction zone 14 can be, for example, micro-structured. In this case, protuberances 15 are present, in greater or lesser number, in relief and projecting with respect to the base surface 16 of the friction zone 14. The base surface 16 of a friction zone is defined , in this document, as being the surface of a friction zone 14, located between the structures in relief 15. This base surface 16 essentially corresponds to the non-deformed surface of a friction zone 14 (therefore also corresponding to the surface of a friction zone before the operation by which the relief structures 15 are produced).

The protuberances 15 are made for example by plastic deformation (stamping) of the sheet in which the contact blades 10 are cut. They protrude at least 3 micrometers from the surface. Indeed, it may be advantageous for their height to be greater than the thickness of the coating layers deposited on the contact blades. For contact blades 10 having a width of the order of 2 millimeters, they have for example a diameter of 50 micrometers. In other words, they each occupy an area of the friction zone substantially equal to 1960 square micrometers. They can be distributed, as shown on the left in FIG. 4, according to a square-mesh network with a pitch of, for example, 200 micrometers. Alternatively, as shown on the right in Figure 4, they are more limited in number (for example two rows of three protrusions 15) so as to further reduce the surfaces interacting with the friction surfaces 8 of the pin 5 of the male contact 1. The configuration shown on the right in Figure 4 has the advantage, compared to that of the figure on the left, that there is no protuberance in the center, in the axis with respect to the contact surface 7 of the pin 5 of the male contact 1. Thus, the protrusions 15 do not rub on this contact surface 7, and therefore do not wear it.

Whatever the number of structures in relief 15, that is to say protuberances in the present case, the sum of the areas individually occupied by each of them is less than the area of the friction zone 14 occupied by all of these structures in relief 15. For example on the left in FIG. 4, the sum of the areas individually occupied by each of them is equal to 24 times 1960 square micrometers, ie 0.047 square millimeters. While the area of the friction zone occupied by all of these structures is 0.56 square millimeters.

When the structures in relief 15 are protrusions, they are arranged on each friction zone 14 so that the pin 5 interacts with all or part of the structures in relief 15 and essentially with the apical surface of these structures in relief 15. Otherwise said, preferably the spindle does not interact with the base surface 16 of the friction zones 14.

Furthermore, as the pin 5 of the male contact 1 does not interact with the entire surface of a friction zone 14, but only with the apical surface of a part (as in figure 4 on the left for example) or all (as in Fig. 4 to the right for example) of the relief structures 15, it can be said that the surface of the friction zone 14 on which the friction zone 14 and a pin 5 of male contact 1 are intended to interact is less than the area delimited by the peripheral limit of the region occupied, on the friction zone 14, by the structure in relief or by all the structures in relief. This is all the more the case when the set of structures in relief 15 with which a male contact 1 is likely to interact is a subset of all the structures in relief 15.

According to the variant of the invention illustrated by FIG. 5, the friction zone 14 comprises structures in relief 15 forming progressive slopes. In this case, these structures form protrusions 15 present, in greater or lesser number, projecting from the base surface 16 of the friction zone 14. These protrusions 15 are produced by plastic deformation (stamping) of the sheet in which are produced the contact blades 10. They can be more or less numerous, for example three in number on each friction zone 14 (on the left in FIG. 5) or two in number on each friction zone 14 (on the left). right in Figure 5). The configuration represented on the right in FIG. 5 has the advantage, compared to that of the figure on the left, that there is no protuberance in the center, in the axis with respect to the contact surface 7 of the pin 5 of the male contact 1. Thus, the protuberances 15 do not rub on this contact surface, and therefore do not wear it. These protrusions 15 each have a friction surface 17 forming a slope having a lower angle β with the central axis C than the angle α between the base surface 16 of the friction zone 14 and the central axis C (see figure 6). It is this friction surface 17 which interacts with pin 5 of male contact 1. Thus, when pin 5 of male contact 1 is inserted into female contact 2, friction surfaces 8 of male contact 1 interact with surfaces 17 of the female contact 2 more progressively than they would have interacts with the base surface 16 of the friction zone 14, therefore devoid of structures in relief 14. The angle between the friction surfaces 8, 17 respective male 1 and female 2 contacts being weaker, these friction surfaces 8, 17 slide over each other more easily.

For this variant again, the sum of the areas A individually occupied by each of the protuberances is less than the area SA of the friction zone 14 occupied by all of these structures in relief 15 (see FIG. 5).

According to the variant of the invention illustrated by FIG. 7, the friction zone 14 comprises structures in relief 15 corresponding to cutouts or openings in the contact blade 10. These cutouts are produced for example by punching. They can be more or less numerous, for example three in number on each friction zone 14 (on the right in FIG. 7) or only one on each friction zone 14 (on the left in FIG. 7).

In this case, the relief is somehow reversed compared to the previous variants. These are then spaces, on the base surface 16, of the friction zones 14 located between the cutouts which interact with the pin 5. The fact of having a hollow in the center, in the axis with respect to the contact surface 7 of pin 5 of male contact 1, avoids friction on this contact surface 7, and therefore does not wear it.

According to the variant of the invention illustrated by FIG. 8, the friction zone comprises structures in relief 15 corresponding to cavities or hollows in the blade. Unlike the previous variant, the contact blade 10 is not perforated right through. The recesses are made for example by stamping. As for the previous variant, they can be more or less numerous, for example three in number on each friction zone 14 (on the right in FIG. 8) or only one on each friction zone (on the left in FIG. 8). These recesses have essentially the same function as the cutouts of the previous variant, but are easier to produce industrially and make it possible to retain more robust friction zones 14.

Regardless of the number and shape of the relief structures 15, their presence on the friction zone makes it possible to reduce the insertion force.

Thus, as shown in Figure 9, with a standard female contact (that is to say with friction zones devoid of structures in relief) it is found that the insertion force increases progressively while the pin 5 is inserted between the contact blades 10. The curve has a maximum which is reached when the friction surfaces 8 of the pin 5 cease to interact with the friction zones 14 of the contact blades 10. Then the insertion force decreases to reach a plateau when contact surfaces 12 of female contact 2 slide on contact surfaces 7 of pin 5.

Figure 9 also shows the insertion force measured for a female contact 2 comprising friction zones 14 with progressive slopes (as illustrated in Figures 5 and 6). In this case, the pin interacts earlier with the friction surface 17 than with the base surface 16 in the case of a standard contact. A threshold is reached when the friction surfaces 8 of the spindle 5 cease to interact with the friction surfaces 17 and it is the contact surfaces 7 of the spindle 5 which slide on the friction surfaces 17. This threshold is very lower than the maximum observed for the insertion force corresponding to the standard contact. Then, the force remains practically constant until the contact surfaces 7 of the pin 5 slide on the contact surfaces 12 of the contact blades 10.

• réduction de l’effort d’insertion ;
• meilleure stabilité de l’effort d’insertion grâce à un meilleur guidage de la broche sur les zones de friction 14 du fait de la présence des structures en relief 15 ;
• réduction de l’usure du contact mâle 1 ;
• facilité de mise œuvre (il y a juste à modifier un outil qui est déjà utilisé pour la réalisation d’un contact standard).

It is therefore found that a contact according to the invention has the following advantages:

• reduced insertion effort;
• better stability of the insertion force thanks to better guiding of the pin on the friction zones 14 due to the presence of the structures in relief 15;
• reduced wear of male contact 1;
• ease of implementation (you just have to modify a tool that is already used for making a standard contact).

The structures in relief 14 described above in relation to FIGS. 4 to 8 are produced by stamping or cutting, but other methods can be envisaged for their production, such as engraving, or the deposition of material, for example.

Claims (10)

A female contact for a connector, this contact (2) comprising a fixing portion (3) and a contact portion (4), the fixing portion (3) being intended for the mechanical and electrical connection of the contact (2) with a cable or an electrical circuit, the contact portion (4) being intended to receive a pin (5) of a male contact (1) inserted into the contact portion (4) parallel to an insertion direction (I),
wherein the contact portion (4) comprises at least one elastic and flexible contact blade (10), this contact blade (10) having a free end (11), at least one contact surface (12), and a friction zone (14) located between the free end (11) and the contact surface (12), this friction zone (14) corresponding to a part of the blade with which the pin (5) of the male contact (I ) interacts mechanically during the insertion of the pin (5) in the contact portion (4), this part of the contact blade (10) being bent to form a non-zero insertion angle (α) with the insertion direction (I),
characterized in that the friction zone (14) has a base surface (16) with at least one structure in relief (15) relative to this base surface (16). Contact according to claim 1, wherein the friction zone (14) comprises a plurality of raised structures (15), each of the raised structures (15) extending over an area (A) of the friction zone (14), and the sum of the areas over each of which a raised structure (15) extends is less than the area (SA) of the friction zone (14) on which the raised structures (15) are distributed. Contact according to Claim 1, in which the friction zone (14) comprises at least one raised structure (15), this raised structure (15) or the set of raised structures (15) occupying a region of the zone friction zone (14), and the area of the friction zone (14) on which the friction zone (14) and a male contact pin (5) (1) are intended to interact, is less than the area ( SA) delimited by the peripheral limit of the region of the friction zone (14) occupied by the or structures in relief (15). Contact according to one of the preceding claims, in which at least one relief structure (15) forms a protuberance with respect to the base surface (16) of the friction zone (14). Contact according to one of the preceding claims, in which at least one relief structure (15) forms a hollow with respect to the base surface (16) of the friction zone (14). Contact according to one of the preceding claims, in which the friction zone (14) corresponds to a part of the contact blade (10) having a section perpendicular to the direction of insertion (I) which is essentially straight. Connection assembly comprising a male connector and a female connector, the female connector comprising at least one female contact (2) according to one of the preceding claims and the male connector comprising at least one male contact (1) with a pin (5) having at least one contact surface (7) interacting with the contact surface (12) of the female contact (2). Connection assembly according to Claim 7, in which the pin (5) of the male contact (1) has, at its free end (6), friction surfaces (8) inclined with respect to the direction of insertion (I ). A method of manufacturing a female contact (2), in which a conductive metal sheet, with two main faces, is cut and folded to form a contact portion (4) of a female contact (2), this contact portion (4) comprising at least one contact blade (10) with a free end (11), at least one contact surface (12), and a friction zone (14) located between the free end (11) and the contact surface (12),
characterized in that it comprises at least one operation during which modifies, on a zone intended to form the friction zone (14), the state of the surface of the main face of the sheet also corresponding to the surface contact (12). A method according to claim 9, wherein the operation of modifying the state of the surface on the friction zone (14) comprises at least one operation chosen from a list comprising cutting, etching and plastic deformation of the sheet.