EP3552277B1 - Method for producing a socket contact and socket contact - Google Patents

Description

The invention relates to a method for producing a socket contact from a round bar. In addition, the invention also relates to a socket contact produced according to the method with a hollow-cylindrical contacting area for contacting a corresponding pin contact and a connection area for connecting an electrical conductor.

Contact elements for the detachable electrical connection of conductors in the form of pin and socket contacts have been known for many years in different variants and for different applications. The electrical contacting between the socket contact and the corresponding pin contact takes place via the contact lamellae formed on the socket contact, which contact the pin contact when it is plugged into the socket contact. For this purpose, the contact lamellae must apply a certain spring force in order to ensure reliable and permanent electrically conductive contact.

The contact elements used extensively in practice are usually manufactured by machining a round rod used as the starting material, with the contact lamellae of the socket contacts being produced by removing the material webs between the individual contact lamellae using a side milling cutter. The resulting contact lamellae of the socket contact are then pressed slightly inwards in order to generate the required spring force. This way of producing a socket contact is very time-consuming, so that the resulting reduced productivity of the production facilities leads to an increase in the costs for the individual socket contacts.

In an alternative method of manufacturing a socket contact, the socket contact is assembled from two components, namely a sleeve closed on one side and a resilient lamellar basket, which is inserted into the sleeve and attached to it. The electrical and mechanical contacting of a corresponding pin contact takes place via the contact lamellae of the lamellar cage, which has a contact area bent inwards for this purpose.

Such a socket contact is, for example, from DE 10 2012 001 560 A1 known. In this known socket contact, the lamellar cage, which is partially arranged inside the sleeve, is bent over the front end of the sleeve onto the outside of the sleeve and is fixed at a fastening point. The spring force of the lamellar basket can be adjusted when the socket contact is made by selecting the distance between the attachment point and the front end of the sleeve. The further away the attachment point is from the front end, the lower the spring force of the slatted basket. The lamellar basket itself is manufactured by stamping it out of a spring sheet metal strip and then bending the contact lamellae. The disadvantage here, however, is that the production of the socket contact is complex and therefore expensive due to the use of two components. In addition, the socket contact has a relatively large volume due to the combination of the two components, so that it is unsuitable for compact plugs.

From the DE 100 41 516 A1 an electrical connection device is known which consists of three parts, namely a resilient plug contact having several contact lamellae, a sleeve-shaped receptacle which can be connected to an electrical conductor by crimping, and a retaining sleeve for locking the connection device in a corresponding mating connector. The resilient plug contact, which is punched out of sheet metal and bent, is permanently connected to the sleeve-shaped receptacle by a riveted connection. Because the plug contact, the receptacle and the holding sleeve are made of different materials, they can each be optimally adapted to their respective purpose. However, this advantage is paid for by the increased effort and the associated costs in the production of the contact element.

the DE 10 2010 020 346 A discloses electrical contact elements in the form of pin and socket contacts, each having a crimp connection as a connection area for connecting an electrical conductor, the connection area being shaped as a hollow cylinder which has a slot in the axial direction. In the case of the socket contact made from solid material, the contact area is formed by a hollow cylinder in which wedge-shaped slots are introduced, so that individual spring arms are formed which serve to contact an inserted pin contact. This are produced by machining steps that are not described in detail, so that the production of these socket contacts is also time-consuming.

Also the JP 2012-221774 A discloses a socket contact with a hollow cylindrical contacting area at one end of the socket contact. Several slits are then milled into the hollow-cylindrical contacting area, which was initially produced by reverse extrusion from a round rod, so that contact lamellae extending in the longitudinal direction and separated from one another by the slits are formed.

The present invention is based on the object of specifying a method for producing a socket contact from a round bar, by means of which the production time is reduced, so that productivity can be increased, in particular when producing socket contacts by machine.

• Herstellen eines hohlzylindrischen Kontaktierungsbereiches an einem ersten Ende des Rundstabes mittels Fließpressen, wobei der hohlzylindrische Kontaktierungsbereich in Längsrichtung des Kontaktierungsbereiches sich erstreckende erste und zweite Abschnitte aufweist, die in Umfangsrichtung des Kontaktierungsbereiches abwechselnd nebeneinander ausgebildet sind, wobei die ersten Abschnitte eine dickere Wandstärke und die zweiten Abschnitte eine dünnere Wandstärke aufweisen
• Anstellen der ersten Abschnitte mit dickerer Wandstärke nach innen, wobei die zweiten Abschnitte mit dünnerer Wandstärke nach außen gebogen oder gefaltet werden.

This object is achieved with the method mentioned at the beginning according to claim 1 by the following steps:

• Production of a hollow-cylindrical contacting area at a first end of the round rod by means of extrusion, the hollow-cylindrical contacting area having first and second sections which extend in the longitudinal direction of the contacting area and are formed alternately next to one another in the circumferential direction of the contacting area, the first sections having a thicker wall thickness and the second sections have a thinner wall thickness
• Pitching the first, heavier-walled sections inwardly with the second, thinner-walled sections bent or folded outwards.

The method according to the invention is first of all characterized in that, instead of a machining production, a metal-forming production by means of extrusion and compression molding is provided. Instead of individual, milled-free contact lamellae, the contacting area of the socket contact according to the invention has first sections which have a thicker wall, these first sections being connected to one another via second sections with a thinner wall. These when queuing The second sections which are bent or folded outwards from the first sections develop a spring effect which counteracts the first sections bending apart. This increases the contact force with which the inwardly inclined first sections of the hollow-cylindrical contacting area press on an inserted pin contact.

Since the first sections of the contacting area, which act as contact lamellae, are not separated from one another by sawing or milling, the production time for producing a socket contact can be significantly reduced. With an appropriately designed forming press, productivity, i.e. the number of socket contacts produced within a certain time, can be increased many times over compared to the production of socket contacts on a lathe or milling machine. Due to the fact that the manufacturing method according to the invention is a non-cutting manufacturing method, the material utilization is also significantly increased since the starting material is utilized up to 100%. In addition to the shorter production time, the material utilization is also significantly increased in the method according to the invention, so that the individual socket contacts can be produced at lower costs.

The hollow-cylindrical contacting area is preferably produced by means of forward extrusion or backward extrusion without prior heating of the round rod as the starting material. The advantage of cold extrusion lies in the high dimensional accuracy and the high surface quality of the component produced in this way, so that post-processing of the socket contacts produced according to the invention is generally not necessary. After being ejected from the forming press, the socket contacts produced in this way may have to be provided with a coating, but otherwise no longer have to be processed further.

In the case of forward extrusion, the first end of the rod is pressed into a die by means of a stamp applied on the back. The die, which is stationary during the forming process, has the negative shape of the desired hollow-cylindrical contact area, with the punch and the material moving in the same direction during forward extrusion. In reverse extrusion, a stamp that has the negative shape of the desired contact area penetrates first end in the round rod. The material is displaced in such a way that it flows into the cavities formed in the stamp in the opposite direction to the direction of movement of the stamp.

Manufacturing the hollow-cylindrical contacting area by means of extrusion has the further advantage that the fiber layer in the socket contact is much better adapted to the load case than is the case when a hollow-cylindrical contacting area is machined. Furthermore, as a result of the inward pitching of the first sections, internal compressive stresses are introduced into the material, as a result of which the spring action of the first sections serving as contact lamellae is improved.

According to an advantageous embodiment of the method according to the invention, the hollow-cylindrical contacting area previously produced by extrusion is inserted into a die for the positioning of the first sections. The die has webs tapering conically inwards, which are arranged corresponding to the first sections. The first sections position themselves in accordance with the conical taper of the inner cross-section of the die, while the second sections with a thinner wall thickness compensate for the decreasing circumference of the hollow-cylindrical contacting area by arching outwards. For this purpose, corresponding recesses are formed in the matrix between the webs, which enable a corresponding outward bending or folding of the second sections.

According to a further preferred embodiment, a corresponding mandrel is arranged in the hollow-cylindrical contacting area while it is being moved into the die. This ensures that the second sections with the thinner wall thickness cannot fold or bulge inwards when the hollow-cylindrical contacting area is moved into the die. When the contacting area is moved out of the die, the second sections are pressed by the mandrel into the corresponding recesses in the die, so that the second sections are given a desired, defined contour.

To connect an electrical conductor to the socket contact, the socket contact has a connection area which is located at a second end of the socket contact, ie at the end facing away from the contacting area. In the method according to the invention for producing a socket contact, such a connection area is preferably produced in a first method step by means of extrusion. The connection area is preferably designed as a hollow cylinder, the connection area being a crimp connection. Such a connection area can also be produced in a simple and cost-effective manner by extrusion, in which case the inner cross section of the connection area can be circular in the simplest case, with a constant diameter over the length of the connection area.

The formation of a hollow-cylindrical connection area in a first method step, i. H. at the beginning of the manufacturing process of the socket contact has the advantage that the connection area can then be used during the manufacture of the hollow-cylindrical contacting area to accommodate a stamp or counter bearing during forward extrusion or reverse extrusion.

In the case of a hollow-cylindrical connection area, a funnel-shaped collar is preferably formed in a further method step at the outer end of the connection area by expanding. The formation of a funnel-shaped collar makes it easier to insert a conductor into the connection area. The formation of an expanded, funnel-shaped collar also makes it possible for the end of the conductor insulation to protrude into the collar in the case of an insulated conductor, while the stripped conductor or the stripped strands are inserted in the hollow-cylindrical connection area. This can prevent damage to the conductor or the strands at the outer end of the connection area.

The aforementioned object is achieved in the case of a socket contact described at the beginning with a hollow-cylindrical contacting area and a connection area with the features of patent claim 7 in that the hollow-cylindrical contacting area has first and second sections which extend in the longitudinal direction of the contacting area and are formed alternately next to one another in the circumferential direction of the contacting area are. The first sections have a thicker wall and the second sections have a thinner wall. In addition, the first sections with thicker wall thickness are inwards employed, while the second sections with thinner wall thickness are bent or folded outwards.

Such a socket contact can be produced particularly easily using the method according to the invention. With regard to the advantages of the socket contact according to the invention, reference is made to the advantages described above in connection with the method according to the invention. The first sections of the contacting area, which are set inwards, serve as contact lamellae, which mechanically and electrically contact a pin contact inserted into the contacting area of the socket contact. The outwardly curved second sections generate an additional spring force, with which the first sections are pressed against an inserted pin contact. The second sections thus have a similar effect to an overspring plugged onto a conventional socket contact, but without two separate components having to be joined together for this purpose.

The angle of attack α, with which the first sections with a thicker wall thickness are inclined inwards, can be set within certain limits, so that the contact force acting on a specific pin contact can be adjusted via the angle of attack realized during production of the socket contact. The setting angle α of the first sections is preferably no more than 10°, in particular no more than 5°, which means that the second sections do not have to be bent outwards too much.

So that the socket contact has sufficient rigidity overall, a solid central area is formed between the hollow-cylindrical contacting area and the hollow-cylindrical connection area. This solid central area preferably extends over at least 25% of the total length of the finished socket contact. In addition, the extension of the middle area is preferably approximately the same size as the extension of the connection area, while the contacting area preferably has a slightly larger extension than the middle area or the connection area. In order to position the socket contact in a housing wall or a carrier plate, at least one stop can also be formed on the central area.

Fig. 1

eine perspektivische Darstellung einer Vorgeometrie eines erfindungsgemäßen Buchsenkontaktes,

Fig. 2

eine perspektivische Darstellung eines erfindungsgemäßen Buchsenkontaktes,

Fig. 3

einen Längsschnitt durch einen erfindungsgemäßen Buchsenkontakt, und

Fig. 4

schematisch mehrere Zwischenschritte bei der Herstellung eines erfindungsgemäßen Buchsenkontaktes.

In detail, there are several possibilities for embodying and developing the method according to the invention and the socket contact according to the invention. For this purpose, reference is made both to the patent claims subordinate to patent claims 1 and 7 and to the following description of preferred exemplary embodiments in conjunction with the drawing. Show in the drawing

1

a perspective view of a pre-geometry of a socket contact according to the invention,

2

a perspective view of a socket contact according to the invention,

3

a longitudinal section through a socket contact according to the invention, and

4

schematically several intermediate steps in the production of a socket contact according to the invention.

1 shows a perspective representation of a pre-geometry 1 'of the socket contact 1 according to the invention, ie the socket contact 1 in the not yet completely finished state. At the in 1 In the pre-geometry 1' shown, a hollow-cylindrical contacting area 2 has been produced at a first end 3 of the socket contact 1 or the pre-geometry 1' by means of extrusion. The hollow-cylindrical contacting area 2 has first sections 4 and second sections 5 extending in the longitudinal direction L, which are formed alternately next to one another in the circumferential direction of the hollow-cylindrical contacting area 2 . The first sections 4 have a thicker wall thickness d ₁ and the second sections 5 have a thinner wall thickness d ₂ . The wall thickness d ₁ of the first sections 4 is significantly thicker than the wall thickness d ₂ of the second sections 5, in particular at least twice as thick.

At the in 1 In addition to the pre-geometry 1' of the socket contact 1 shown, a connection area 7 is formed as a hollow-cylindrical crimp connection at the second end 6 of the socket contact 1, the connection area 7 also having been produced by extrusion. At its outer end, the connection area 7 has a funnel-shaped collar 8 which has been produced by widening the connection area 7 . The funnel-shaped collar 8 makes it easier to insert a conductor to be connected, in particular a stranded conductor, into the connection area 7 before the conductor is firmly and electrically conductively connected to the socket contact 1 by crimping.

As in particular from the sectional view of the socket contact 1 according to 3 As can be seen, the socket contact 1 also has a solid central area 9 which is formed between the hollow-cylindrical contacting area 2 and the hollow-cylindrical connection area 7 . A stop 10 is formed on the central region 9 and can serve as a stop for fastening the socket contact 1 in a housing wall or a carrier plate.

Out of 2 it can be seen that in the case of the fully manufactured socket contact 1 shown there, the geometry of the contacting area 2 compared to the pre-geometry 1' according to FIG 1 is changed. In the finished socket contact 1, the first sections 4 with a thicker wall thickness d ₁ are set inwards, while the second sections 5 with a thinner wall thickness d ₂ are arched or bent outwards. The second sections 5 bent outwards when the first sections 4 are placed in position develop a spring effect which counteracts the first sections 4 bending apart when a corresponding pin contact is inserted into the socket contact 1 . As a result, the contact force with which the inwardly inclined first sections 4 of the contacting region 2 press on an inserted pin contact is additionally increased.

In 3 the angle of incidence α of the first sections 4 is drawn in, which is preferably less than 10°, in particular less than 5°. The setting angle α can be adjusted within certain limits during the manufacture of the socket contact 1, as a result of which the socket contact 1 and in particular its contact force can be adapted to a pin contact to be contacted. The greater the angle α of the first sections 4, the more the second sections 5 must be bent outwards in order to compensate for the decreasing circumference of the hollow-cylindrical contacting area 2.

4 shows various steps in the production of the socket contact 1 from a solid round bar 11 as the starting workpiece. In a first In the first method step, a first punch 12 is pressed into the rod 11 at the second end 6 , as a result of which the material of the rod 11 is displaced in such a way that it flows in the opposite direction to the direction of movement of the punch 12 . As a result, the hollow-cylindrical connection area 7 is produced in the first method step. In the same method step, or in a subsequent method step, the outer end of the hollow-cylindrical connection area 7 is widened, as a result of which the funnel-shaped collar 8 is formed.

To produce the hollow-cylindrical contacting area 2 , a second die 13 , which has the negative shape of the desired contacting area 2 , is pressed into the round rod 11 at the first end 3 . The material of the rod 11 is also displaced during this reverse extrusion in such a way that it flows in the opposite direction to the direction of movement of the punch 13 into the recesses 14 formed in the punch 13 . At the end of this manufacturing step, the socket contact 1 essentially has a shape or geometry that corresponds to that in 1 shown pre-geometry 1 'of the socket contact 1 corresponds. The contacting area 2 has first sections 4 with a thicker wall thickness d ₁ and second sections 5 with a thinner wall thickness d ₂ .

To place the first sections 4 of the contacting area 2, the socket contact 1 with the contacting area 2 in a in the last figure 4 die shown 15 retracted, which has conical inwardly tapering webs. The webs are arranged to correspond to the first sections 4 of the contacting region 2, so that the first sections 4 are positioned inwards in accordance with the conical narrowing of the inner cross section of the matrix 15. The second sections 5 with a thinner wall thickness compensate for the decreasing circumference of the hollow-cylindrical contacting area 2 by arching outwards. For this purpose, corresponding recesses are formed in the matrix 15 between the webs, which enable the second sections 5 to bulge outwards.

In order to ensure that the second sections 5 do not bulge inwards when the contacting area 2 is inserted into the previously described die 15, a mandrel 16 is arranged in the hollow-cylindrical contacting area 2 during this method step. The mandrel 16 has it a geometry similar to that of the stamp 13, so that recesses 17 are formed in the mandrel 16, which receive the first sections 4 of the contacting region 2. In addition, the mandrel 16 has webs 18 formed between the recesses 17 which prevent the second sections 5 of the contacting region 2 from bulging inwards when they are inserted into the die 15 . When the contacting area 2 of the socket contact 1 is moved back out of the die 15, the second sections 5 are pressed by the mandrel 16 or its webs 18 into the corresponding recesses in the die 15, so that the second sections 5 receive the desired, defined contour. After this production step, the socket contact 1 is finished and can be provided with a coating if required.

Claims (10)

1. Method of manufacturing a socket contact (1) from a rod (11), characterized by the following steps,

   • producing a hollow cylindrical contact region (2) at a first end (3) of the rod (11) by extrusion, wherein the hollow cylindrical contact region (2) has first and second sections (4, 5) extending in the longitudinal direction (L) of the contact region (2) and formed alternately side by side in the circumferential direction of the hollow cylindrical contact region (2), wherein the first sections (4) have a thicker wall thickness (d₁) and the second sections (5) having a thinner wall thickness (d₂)

   • positioning the first sections (4) with thicker wall thickness (d₁) inwardly, wherein the second sections (5) with thinner wall thickness (d₂) are bent or folded outwardly.
2. Method according to claim 1, characterized in that the hollow-cylindrical contact region (2) is inserted into a die (15) for positioning the first sections (4), wherein the die (15) has inwardly tapering bars corresponding to the first section (4) and recesses arranged between the bars, which recesses allow the second sections (5) to be bent or folded outwardly.
3. Method according to claim 2, characterized in that a mandrel (16) is arranged in the hollow cylindrical contact region (2) while the contact region (2) is inserted into the die (15).
4. Method according to any one of claims 1 to 3, characterized in that the hollow cylindrical contact region (2) is produced by means of forward extrusion or reverse extrusion.
5. Method according to any one of claims 1 to 4, characterized in that, in a first method step, a connecting region (7) for connecting an electrical conductor is produced at the second end (6) of the rod (11) by means of extrusion.
6. Method according to claim 5, characterized in that the connecting region (7) is formed as a hollow cylindrical crimp connection and, in a further method step, a funnel-shaped collar (8) is formed at its outer end by expansion.
7. Socket contact (1) having a hollow cylindrical contact region (2) for contacting a corresponding pin contact and having a connecting region (7) for connecting an electrical conductor, wherein the socket contact (1) is produced in accordance with the method according to any one of claims 1 to 6, characterized in

   that the hollow cylindrical contact region (2) has first and second sections (4, 5) extending in the longitudinal direction (L) of the contact region (2) and formed alternately next to one another in the circumferential direction of the contact region (2), wherein the first sections (4) have a thicker wall thickness (d₁) and the second sections (5) have a thinner wall thickness (d₂), and

   that the first sections (4) with a thicker wall thickness (d₁) are turned inwards and the second sections (5) with a thinner wall thickness (d₂) are bent or folded outwards.
8. Socket contact (1) according to claim 7, characterized in that the positioning angly α of the first sections (4) with thicker wall thickness (d₁) is less than 10°, in particular less than 5°.
9. Socket contact (1) according to claim 7 or 8, characterized in that the connecting region (7) is formed as a hollow cylindrical crimp connection and a funnel-shaped collar (8) is formed at its outer end.
10. Socket contact (1) according to any one of claims 7 to 9, characterized in that a solid middle region (9), which preferably has a stop (10), is formed between the hollow cylindrical contact region (2) and the hollow cylindrical connecting region (7).

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