EP3349307B1 - Electrical press-in contact element - Google Patents

Description

Technical field

The invention relates to an electrical press-in contact element with at least one press-in section, which extends in an extension direction from a root region, in which the press-in section is connected to a contact body, to a free end, and which has a central zone which extends from both sides of the root region to the free end is flanked by an edge zone, the edge zones forming contact surfaces which point away from one another and which, after the insertion of the press-in section into a press-in opening, for example abut a circuit board on the wall of the press-in opening.

State of the art

A press-in contact element is from the DE 198 31 672 B4 previously known. The press-in contact element disclosed there has a press-in section which is connected to a contact body. The contact body has a contact element. The press-in section is in the form of a pin and, in a conductively connecting, elastically prestressed system, can come into contact with the inner wall of a hole in a printed circuit board which forms a press-in opening. The application of the force in order to press the press-in section into the plated-through hole of the printed circuit board is carried out by axially acting on a press-in shoulder which is formed by the contact body. Here, the bulbous or oblique shape of the contact used in the prior art until it has reached its largest enveloping circle diameter has proven to be advantageous for achieving the lowest possible indentation forces. Press-in contacts of this type are used to produce solderless electrical connections in accordance with DIN EN 60352-5 and are in Longitudinal direction from the press-in end with an integrally connected plug end, connection area or lead frame.

In order not to damage the printed circuit board and its plated-through hole and in particular the inner conductor tracks during the pressing in, it makes sense that the press-in section is designed to be elastic and presses on the hole wall with relatively little force. In order to achieve this, a relatively low normal force of the legs of the press-in sections resting against the hole wall should be aimed for. However, the required pushing-out force of the press-in sections from the printed circuit board perforation must be relatively high for reasons of stability, in particular in the case of free-standing contacts. However, this requirement, which is important in terms of quality, cannot be achieved with small material thicknesses of the press-in contact formed by press-in sections, in particular if the normal force of the legs of the press-in contacts is low. A low pushing-out force or holding force is also disadvantageous in the case of vibration loads, such as occur in automotive applications in the engine compartment, since the contacts can loosen, which increases the contact resistance. Such damage can lead to total failure of the electrical connection.

Such press-in contacts are often connected to continuing areas using the same material. These can be designed as socket contacts for circular or flat plugs, crimp connections, insulation displacement connections, film connections or lead frames, etc. Such applications require resilient, elastic properties in order to enable perfect contacting with the mating connector or connecting part. Therefore, the material thickness is usually low, for example 0.3 mm. However, this thickness is sometimes not sufficient to meet the above requirements for such press-in contacts. In particular, because of the small material cross sections and the relatively small contact area in the printed circuit board perforation, the desired high one Current carrying capacity and the desired cold welding often cannot be achieved. Therefore, in the prior art, such components are made from step-milled strip material. This means that the tape, for example 0.8 mm thick for the area of the press-in zone, must be reduced to 0.3 mm in the area of the subsequent contact areas. Since this process is usually carried out by milling, such belts are expensive. Typically, such press-in contacts, which are made of bare tape, are provided with a galvanic surface in a further step. This consists of pure tin due to the required cold welding with the through-plating of the circuit board and the lead-free regulation. However, it is known that galvanically pure tinned surfaces under pressure and bending stress which arise in a press-fit connection are susceptible to whisker formation. These whiskers are undesirable and can cause short circuits when used. Furthermore, the continuing areas are often made of pre-coated tape for cost reasons and therefore have bare cut edges. These can be disadvantageous when used as a contact surface for press-in contacts in the through-plating of the printed circuit board. Therefore, in the prior art, these press-fit areas are galvanically coated in a separate operation. This additional work step is very cost-intensive and complex.

The prior art also include DE 38 31 508 C2 and the US 4,017,143 , each showing an electrical press-in contact element, in which the press-in section is given a cross-sectional profile by stamping with a stamp.

The US 6,132,225 discloses a press-in section which is curved around a single bending line over its entire direction of extent, so that Form protruding edge zones from the original extension plane of the sheet metal blank.

The DE 10 2014 107 438 A1 discloses a slotted press-in section with an embossed recess.

The DE 20 2009 009 933 U1 discloses a slotted press-in section with impressions on both sides, so that webs form in a contact area.

The DE 20 2016 102 148 U1 discloses a press-in section consisting of two parallel legs.

The EP 0 313 300 A1 discloses a press-in section, in the contact area of which a cross-sectionally V-shaped groove is embossed.

The DE 90 16 257 U1 and the DE 10 2015 200 491 A1 disclose press-in sections with depressions pressed into the contact area.

The DE 11 2006 000 095 T5 discloses a press-in section with legs which are separated by a free space and can be moved elastically towards one another.

A generic press-in contact element discloses the DE 10 2012 224 225 A1 . Lateral webs protrude from a substantially flat central zone, the ends of which come into contact with one another when the press-in contact element is pressed in. The contact areas are formed by rounding sections.

Summary of the invention

The invention is based on the object of developing the electrical contact element mentioned at the outset in a manner which is advantageous in terms of use and in particular of changing the elastic region of the press-in section in such a way that the normal force of the two legs of the press-in section is relatively low, and in particular that a bulbous or oblique region of the press-in section is reached until it is reached of the largest envelope diameter of the contact is retained.

The object is achieved by the invention specified in claim 1.

First and foremost, it is provided that the edge zone is bent away from the central zone. It can further be provided that the press-in section has a U-shaped or C-shaped cross-section. An S-shaped or Z-shaped cross section is also possible. In a cross-sectional plane through the direction of extension of the press-in section, a curved material strip is formed, the edge of which is formed by the edge zones and the central section by the central zone. The press-in section preferably has such a curved shape over its entire length. The press-in contact element has a press-in section which is formed by a flat piece, the edge zones of which are each bent away from the central zone by a bending line. According to the invention, the U or C or Z cross-sectional profile is produced by a bending deformation around a bending line, in which the narrow edges of the flat piece point in the direction of the broad side of the flat piece after the bending deformation and the contact surfaces are formed by the edge sections of the broad side surfaces of the flat piece. The middle Section can extend along a straight line, which can, if the press-in section has a U-shape in cross section, form the U-leg. The two edge zones then form the two U-legs. In the case of an S-shaped or Z-shaped cross section, the two edge sections point in directions pointing away from one another. The edge zones preferably form webs projecting from the central zone. It can get between the fringes Extend channel, the bottom of which is the central zone. This channel preferably runs over the entire length of the press-in section, that is from the root area to the free end. The press-in section is preferably an integral part of a stamped and bent part from which the press-in contact element is made. After the reshaping, the stamped beige part forms a contact body which has contact elements designed in a variety of forms, for example for inserting a plug or for clamping a cable. The press-in contact element can have a plurality of press-in sections which extend parallel to one another. Each press-in section preferably forms an outer surface and an inner surface opposite this. The outer surface and the inner surface are formed by the two opposite broad side surfaces of the sheet metal part, from which the press-in contact element is formed. The edge zones are bent away from the plane of extension of the sheet. In particular, they are bent away from the outer surface, so that in a preferred embodiment the outer surface of the press-in section has a rounded section, which in particular connects an outer surface section of the central zone to the contact surface which is formed by an outer surface section of the edge zone. An inner surface of the press-in section can have a section assigned to the central zone and a section running essentially perpendicularly thereto. The section of the inner surface assigned to the central zone is preferably flanked on both sides by sections of the inner surface of the peripheral zone which are perpendicular to the section of the central zone. The two sections of the inner surface running parallel to one another adjoin one another at bending lines. In a development of the invention, it is provided that an outline contour line of the press-in section runs in an arcuate manner in a connection area, the connection area extending from a first narrow area of the press-in section to the root area. A contact area adjoins the connection area, in which the contact areas sit, which come into electrical contact with the plated-through press-in openings. in the The area of the press-fit section has a bulbous shape in the contact area. Starting from the first narrow area, the outline contour line extends on an arc line, the two arc lines being directed away from one another, so that an area with the largest diameter is formed between two narrow areas of the press-in section, in which the contact surfaces are arranged. In the contact area, which extends between the connection area and the end area, a slot, an indentation and / or a curvature is preferably arranged. The indentation can have rounded edge edges and be arranged in the region of the slot, the indentation being formed in particular on the inner surface. The outer surface opposite the inner surface preferably has a curvature which lies opposite the embossing. If the contact body has a hollow shape and a plurality of press-in sections are provided which protrude from the edge of the hollow shape, it is particularly provided that the webs formed by the edge zones are directed outwards, whereas the curvatures of the outer surface opposite the webs are directed inwards, i.e. in the direction of the Show cavity of the hollow form. With the configuration according to the invention, a press-in section of a generic press-in contact element is given increased stability. A slot which extends in the central zone and is flanked on both sides by the contact surfaces. The slot divides the press-in section into two contact legs, which can deform elastically towards one another. According to the invention, the normal force of the contact legs of the press-in contact is relatively low. The bulbous or oblique area of the contact surface or the outer surface formed by the edge zone is retained until the contact's largest enveloping circle diameter is reached, as a result of which low indentation forces arise. However, the pressing-out forces that arise when the press-in contact is pressed out or the holding forces remain relatively high. The material thickness of the press-in section uniformly connected to the contact body is the same. The stability of the press-in section has increased due to the bent edge zone. Furthermore, the contact area has also increased. The current carrying capacity is therefore relatively high. The through-plating of a printed circuit board is not damaged when the press-in section is inserted. The contact resistance is also low. The entire component is preferably made of the same material from a strip of the same thickness with a uniform precoating. The tape has a pre-coated surface. Electroplating is possible, but is preferably not necessary. The surface can also be electroplated with silver or a silver-tin alloy, gold or another suitable metal. The coating can also be applied subsequently.

It is also advantageous if the contact body and the press-in section, that is to say in particular the entire press-in contact element, are produced from a pre-coated metal strip. The manufacturing steps are essentially punching and bending. In this case, press-in sections that are curved outwards and have contact legs are formed. The contact legs, which are separated from one another by the slot, then preferably each have an L-shape. The outwardly arched contact legs have webs that are bent upwards in terms of bending technology, which serve as contact surfaces and for stabilization and, on the one hand, due to pressurized deformation, have a depression in the shape of a calotte, the outer radius of which is smaller than the outer radius of the bulbous shape of the press-in contact. They change the bending radius of the raised webs in the area of the bulbous shape in such a way that a contour is created which increases the holding force of the press-in contact in the through-connection and at the same time forms a larger current-carrying area in the area of the contact for better current transmission. In order to make the normal force of the press-in zone adjustable, the calotte, in particular produced by an embossing, is slit in the middle with the slot mentioned. The width or length of this slot causes a change in the material cross section and thus an adjustability of the normal force. This is particularly important if the press-in section is a direct connector is used for printed circuit board perforations, to stabilize the area between the press-in section and a contact element which is formed by the contact body. In a preferred embodiment, the contact body has a stiffening bead in the root region, which, if the contact body is a hollow body, is preferably curved inwards. The contact elements can be made of a copper alloy. A socket contact, an insulation displacement connection, a foil connection or a crimp connection can be considered as the contact element. The socket contact can have a free cut. A positioning stop is also provided, which abuts the surface of the printed circuit board when the press-in contact element is pressed in. The socket contact can have a plurality of curved contact lamellae. An insertion slot for a plug is formed between the contact lamellae. The contact lamellae can be provided with radius-shaped contact points, in the extension of which a further radius is arranged on the end face for contact with the socket wall, which is formed in particular by the inner wall of the contact body designed as a hollow body.

The channel extending between the entire length of the press-in section is delimited by the two webs. The two webs essentially form flat channel inner walls, which merge into a flat channel floor, which is formed by the central zone, with the formation of a kink or bend line. The two webs have a constant height over their entire length. The outer walls of the webs, which form the contact areas in the contact area, run at least in regions on levels which, with the formation of curves, merge into an outer wall opposite in the bottom of the channel. The contour line of the webs runs in the plane of the central zone along curved lines which have the maximum distance from one another in the central region of the inlet section.

Brief description of the drawings

Fig. 1

eine erste perspektivische Darstellung eines Einpresskontaktelementes mit einem kastenförmigen Kontaktkörper und drei Einpressabschnitten,

Fig. 2

das Ausführungsbeispiel in einer zweiten perspektivischen Darstellung,

Fig. 3

das Ausführungsbeispiel in einer Seitenansicht,

Fig. 4

das Ausführungsbeispiel in einer Unteransicht,

Fig. 5

das Ausführungsbeispiel in einer Draufsicht,

Fig. 6

den Schnitt gemäß der Linie VI - VI in Figur 3,

Fig. 7

eine vergrößerte Draufsicht auf die nach außen weisende Breitseite eines Einpressabschnittes,

Fig. 8

den Schnitt gemäß der Linie VIII - VIII in Figur 7,

Fig. 9

den Schnitt gemäß der Linie IX - IX in Figur 7,

Fig. 10

den Schnitt gemäß der Linie X - X in Figur 7,

Fig. 11

den Schnitt gemäß der Linie XI - XI in Figur 7,

Fig. 12

eine Draufsicht auf das freie Ende 4 des Einpressabschnittes,

Fig. 13

ein zweites Ausführungsbeispiel der Erfindung in einer Draufsicht,

Fig. 14

das zweite Ausführungsbeispiel in einer Seitenansicht,

Fig. 15

ein drittes Ausführungsbeispiel der Erfindung in einer Draufsicht,

Fig. 16

ein viertes Ausführungsbeispiel der Erfindung in einer Draufsicht und

Fig. 17

das vierte Ausführungsbeispiel in einer Seitenansicht.

The invention is explained in more detail below on the basis of exemplary embodiments. Show it:

Fig. 1

a first perspective view of a press-in contact element with a box-shaped contact body and three press-in sections,

Fig. 2

the embodiment in a second perspective view,

Fig. 3

the embodiment in a side view,

Fig. 4

the embodiment in a bottom view,

Fig. 5

the embodiment in a plan view,

Fig. 6

the section according to the line VI - VI in Figure 3 ,

Fig. 7

2 shows an enlarged top view of the broad side of a press-in section pointing outwards,

Fig. 8

the section along the line VIII - VIII in Figure 7 ,

Fig. 9

the section along the line IX - IX in Figure 7 ,

Fig. 10

the section along the line X - X in Figure 7 ,

Fig. 11

the section according to the line XI - XI in Figure 7 ,

Fig. 12

a plan view of the free end 4 of the press-in section,

Fig. 13

a second embodiment of the invention in a plan view,

Fig. 14

the second embodiment in a side view,

Fig. 15

a third embodiment of the invention in a plan view,

Fig. 16

a fourth embodiment of the invention in a plan view and

Fig. 17

the fourth embodiment in a side view.

Description of the embodiments

The press-in contact elements shown in the drawings are made from a metal strip as the starting material. The metal strip can be a tin-plated metal strip. The metal strip preferably consists of a non-ferrous metal and in particular a copper alloy. First, a stamped part is produced from the metal strip in a stamping process, which can subsequently be galvanically coated. In a subsequent, in particular multi-stage bending process, the press-in contact element is given its final shape, which is shown in the figures.

The press-in contact element has a contact body 1, which can be designed according to the application and can have variously designed contact elements 14, with which the contact body 1 is in electrically conductive contact with a cable or another electrically conductive material can be brought. The contact body 1 is connected in the same material as at least one press-in section 2, which can be inserted into a plated-through press-in opening of a printed circuit board. In order to limit the insertion depth, the contact body 1 has a positioning stop 15 which, in the pressed-in state, rests on a broad side plane of the printed circuit board.

That in the Figures 1 to 6 The first exemplary embodiment shown has a box-shaped contact body 1, which forms a hollow body. The contact body 1 has a slot on a contact side for inserting a plug. The contact elements 14, which protrude from the slot edge, form lamellae which protrude into the cavity of the contact body 1. The contact elements 14 form inwardly curved contact lamellae which bear with rounded contact points on a plug inserted into the socket contact. The contact slats continue beyond the contact points and also form curves there. A rounding section can rest on the inner wall of the contact body 1. The contact body 1 is formed from a metal sheet which is brought into a box shape. There is a link 17 at the separation points.

That in the Figure 13 The illustrated embodiment of a press-in contact element has a contact element 14 in the form of a crimp connection. That in the Figure 15 The illustrated embodiment has a contact element 14 in the form of an insulation displacement connection and that in the Figures 16, 17 The illustrated embodiment has a contact element 14 in the form of a film connection.

The press-in section 2 in the Figures 13 to 17 Embodiments shown or the press-fit sections 2 of the in the Figures 1 to 6 shown Embodiment is in the Figures 7 to 12 shown enlarged and is described below.

The press-in section 2 extends in an extension direction E from a root area 3, which lies in a connection area B, and in which the press-in section 2 is connected to the contact body 1 in the same material, via a contact area A to a free end 4, which is the end of a End area C forms. The press-in section 2 is formed by a narrow metal strip which has a central zone 5 which is flanked on both sides by an edge zone 6 over its entire length extending from the root region 3 to the free end 4. An outline contour line 2 'of the press-in section 2 is thus formed by the two edge zones 6.

The two edge zones 6 form webs bent out from the plane of extent of the central zone 5, which give the cross section of the press-in section 2 a U-shape. In the exemplary embodiments, the edge zones 6 are bent away from the central zone 5 in the same direction. However, it is also provided that the edge zones 6 are bent away from the central zone 5 in different directions from one another, so that the webs protrude from the central zone 5 in directions pointing away from one another. Such a press-in section can have an S-shaped or Z-shaped cross section.

The webs formed by the edge zones 6 merge obliquely into the surface of the contact body 1 in the root region 3. The outline contour line 2 ′ runs in the connection region B there, starting from a narrow region of the press-in section 2, along an arc line in order to end at an edge edge of the contact body 1. The narrow area in the transition area between that in the connection area B and the contact area A corresponds approximately to the distance between the two contour lines 2 ′ in the region of the free end 4.

In the connection area A, the press-in section 2 has a bulbous contour. The contour lines 2 'each run on an arc line, the two arches pointing away from each other, so that the press-in section 2 has its greatest width approximately in the middle of the contact area A.

From the Figures 9 and 12 it can be seen that the cross-sectional length of the central zone 5 is approximately twice as long as the two edge zones 6, which extend essentially at right angles to the central zone 5. An outer surface 8 of the press-in section 2 runs essentially flat in a section 8 ′ of the central zone 5 and forms in the transition region a rounded section 8 ′ ″ to the edge zone 6. The rounded section 8 ′ ″ connects the essentially flat section 8 ′ to a likewise rounded section or section 8 ″ which is flat in some areas and which forms a contact surface. The outer surface section 8 ″ forming the contact surface becomes formed from the outside of the central zone 5 and, in the pressed-in state, bears against the plated-through wall of the press-in opening of the printed circuit board in an electrically conductive manner.

The rounding of the section 8 ″ can continue up to a section 9 ″ of an inner surface 9 which lies opposite the outer surface 8. The inner surface section 9 "runs essentially flat and is assigned to the edge zone 6. When a bending line 9"'is formed, the inner surface section 9 "merges into a flat inner surface section 9' approximately at the formation of a right angle, which runs parallel to the outer surface section 8 '. A channel 7 with channel walls 9 ″ and a channel bottom 9 ′ is thus formed.

The bending line 9 "essentially follows the outline contour line 2 '. It runs at the same distance from the outline contour line 2'.

The central zone 5 has in the connection region B, that is to say in the region of its greatest width, a slot 10 which extends in the direction of extension E and which there separates the press-in section 2 into two contact limbs which can be moved elastically towards one another, the width of the slot 10 being reduced . An impression 12, which is dome-shaped and has a rounded edge 12 ', which adjoins the bending line 9 "' in an apex region, contributes to influencing the elasticity of the contact legs.

The indentation 12 is assigned to the inner surface 9. The area of the outer surface 8 opposite the embossment 12 has a curvature 11.

In the area of the root 3, a reinforcing bead 13 is also provided, which extends into the root area 3 and which sits approximately in the axial center of the press-in section 2. <b> List of reference symbols </b> 1 Contact body A Contact area 2nd Press-in section B Connection level 2 ' Outline contour line C. End area 3rd Root area 4th free end E Extension direction 5 Middle zone 6 Edge zone 8th Outside surface 8th' section 8th" Contact area 8th"' rounded section 9 Inner surface 9 ' section 9 " section 9 '" Bending lines 10th slot 11 Bulge 12th Embossing 13 Reinforcing bead 14 Contact elements 14 ' Contact point 15 Positioning stop 16 Indentation shoulder 17th Clinking

Claims (13)

1. An electric press-in contact element with at least one press-in section (2), which has a length extending in a direction of extension (E) from a root area (3), in which the press-in section (2) is connected with a contact body (1), up to a free end (4), and forms a connection area (B) that adjoins the root area (3), a contact area (A) adjoining the former, and an end area (C) that extends from the contact area (A) up to the free end, wherein a middle zone (5) running in the direction of extension (E) is flanked over its entire length and on either side by a respective edge zone (6) which forms webs being bent away from the middle zone (5), between the webs extends a channel over the entire length of the press-in section (2), whose floor is the middle zone, wherein the edge zones (6) form contact surfaces (8") in the contact area (A), which abut against the wall of the press-in opening after inserting the press-in section (2) into the press-in opening, wherein an inner surface of the press-in section (2) comprises a portion (9') running in the plane of extension of the middle zone (5) and two portions (9") of the webs adjoining the bending line, characterized in that the portions (9") of the webs running perpendicular to the portion (9') of the middle zone (5) comprising a slot (10) in that way, that the contact surfaces (8") can resiliently deform towards each other.
2. The electric press-in contact element according to claim 1, characterized in that an outer surface (8) of the press-in section (2) has a rounded section (8'''), which joins an outer surface section (8') of the middle zone (5) with the regionally flat running contact surface (8").
3. The electric press-in contact element according to one of the preceding claims, characterized in that an outline contour line (2') of the press-in section (2) lying in the extension plane of the middle zone (5) runs along an arc in a connection area (B) extending from a first narrow area up to the root area (3).
4. The electric press-in contact element according to one of the preceding claims, characterized in that, the middle zone (5) comprises an impression (12) being located in the contact area (A), wherein in particular it is provided that the impression (12) has rounded edges, being allocated to the inner surface (9) and lying opposite the curvature (11).
5. The electric press-in contact element according to one of the preceding claims, characterized in that the middle zone (5) has a curvature (11) in the contact area (A).
6. The electric press-in contact element according to one of the preceding claims, characterized in that the outline contour line (2') of the press-in section (2) runs along lines bent away from each other in connection area (B) and/or in contact area (A).
7. The electric press-in contact element according to one of the preceding claims, characterized in that one or several press-in sections (2) are integrally joined with the contact body (1), the contact body (1) and the at least one press-in section (2) consist of a uniform starting material, wherein the press-in contact element preferably is made out of a metallized, for example a silver-plated, gold-plated or pre-tin-plated strip, in particular a hot-dip pre-tin-plated strip, as the stamped and bent part, and has a reinforcing bead (13) in the root area (3).
8. The electric press-in contact element according to one of the preceding claims, characterized in that the material of the press-in contact element is a copper alloy.
9. The electric press-in contact element according to one of the preceding claims, characterized in that the contact body (1) has contact elements (14), which in particular form a socket contact, and that the contact body (1) is box-shaped or round, and clinched and/or laser-welded at separating points.
10. The electric press-in contact element according to one of the preceding claims, characterized in that the contact body (1) has a free section and a positioning stop (15) on either side.
11. The electric press-in contact element according to one of the preceding claims, characterized in that side walls of the contact body (1) have push-in shoulders (16).
12. The electric press-in contact element according to one of the preceding claims, characterized in that the contact elements (14) form inwardly bent contact lamellae, which are provided with radius-shaped contact points (14').
13. The electric press-in contact element according to one of the preceding claims, characterized in that the contact element (14) is an insulation-displacement connection, that the contact element (14) is a foil connection, and/or that the contact element (14) is a crimped connection.

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