EP1700516B1 - Arrangement with a contact element - Google Patents

Abstract

A circuit board (20) is equipped with at least one conductor path (22) and a contact element (44). The latter is adapted to mechanically engage and electrically contact an electrical conductor (66). In the region of a conductor path (22), the circuit board (20) has passthrough orifices (24, 26, 28, 30, 32). The contact element (44) has a base part (46) and feet (34, 36, 38, 40, 42) which press-fit into the orifices (24 to 32) of the circuit board (20). The contact element (44) has a contact tongue (54) that is resiliently articulated on the base part (46) and clamps the electrical conductor (66). This makes possible a secure connection from the electrical conductor (66) to the circuit board (20), e.g. for connecting a device having a large current demand.

Description

The invention relates to an arrangement with a printed circuit board, which is provided with at least one conductor track and a contact element for producing an electrical connection between an electrical conductor and a predetermined conductor track on this circuit board.

In various applications, eg. As in automotive technology, on a ship or in aviation, it is necessary to connect a predetermined trace, which is located on a printed circuit board, mechanically and electrically safe with an electrical conductor coming from the outside. This electrical conductor can, for. B. for power supply, and in this case may occur during operation of the vehicle no interruption of the power supply.

This connection can also serve for connection to the electric motor of a safety-relevant application, for. B. with a motor which is controlled by the circuit board. This can z. B. be an application in which a movement is electrically controlled (x-by-wire). Again, a reliable connection throughout the life of the motor vehicle, aircraft, ship or the like. Required.

In addition, it should be noted that such electrical connections must be carried out as automated as possible, so that their production / assembly is inexpensive possible.

DE 101 57 113 relates to an arrangement with a printed circuit board provided with at least one conductor track and a contact element for contacting an electrical conductor, which serves for connection to this printed circuit board. The circuit board has continuous recesses in the region of a conductor track. The contact element has a base part, provided thereon legs for pressing in recesses of the circuit board and a contact tongue, which is articulated resiliently on the base part and is designed for contacting the electrical conductor, wherein the pressing of the legs in the recesses a mechanical and electrical connection with the conductor track causes.

It is therefore an object of the invention to provide a novel arrangement of the type mentioned.

According to the invention, this object is achieved by the subject matter of claim 1.

The invention provides a reliable mechanical and electrical connection between the printed circuit board and the contact element, since the legs in the recesses of the Printed circuit board to be pressed (press-fit). These recesses are electrically connected via their metallization with the conductor tracks of the circuit board and the circuit located there, and they are electrically and mechanically connected by pressing the legs of the contact element. The latter in turn allows a reliable connection with the coming from the outside electrical conductor.

The contact element is therefore already electrically connected by the press-fitting with the predetermined conductor track, and in addition one obtains a flat solder joint between it and the conductor track. In the so-called reflow process, therefore, a solder joint is produced between the contact element and the conductor track, ie. H. When heating the PCB in the reflow oven, the solder can reach all desired locations. These solder joints also form, in addition to the mechanical and electrical connection created by the press-in technique, a secure electrical connection and support the mechanical connection created by the press-fitting. Despite cost-optimal processes, this provides a high level of functional safety of the connection between the contact element and the printed circuit board / conductor track, namely electrically and mechanically.

In the invention, therefore, the consideration is in the foreground to create a connection that is very safe and reliable and therefore has some redundancy.

Fig. 1

eine Draufsicht auf eine Leiterplatte, auf der sich eine Leiterbahn befindet, und die mit Bohrungen nach einem vorgegebenen Muster versehen ist,

Fig. 2

eine Draufsicht analog Fig. 1, bei der auf der Leiterplatte 20 ein Kontaktelement nach einem ersten Ausführungsbeispiel der Erfindung befestigt und mit der Leiterbahn elektrisch verbunden ist,

Fig. 3

einen Schnitt, gesehen längs der Linie III-III der Fig. 2,

Fig. 4

einen Schnitt, gesehen längs der Linie IV-IV der Fig. 2

Fig. 5

eine bevorzugte Variante zu Fig. 3,

Fig. 6

eine raumbildliche Darstellung eines vereinfachten Kontaktelements nach einem zweiten Ausführungsbeispiel der Erfindung, und

Fig. 7

eine Darstellung einer Leiterplatte mit dem Kontaktelement der Fig. 6.

Further details and advantageous developments of the invention will become apparent from the described below and illustrated in the drawings, in no way as a limitation of the invention to be understood embodiments, and from the other dependent claims. It shows:

Fig. 1

a plan view of a printed circuit board on which a conductor track is located and which is provided with holes according to a predetermined pattern,

Fig. 2

1 is a plan view similar to FIG. 1, in which a contact element according to a first exemplary embodiment of the invention is fastened to the printed circuit board 20 and electrically connected to the printed conductor,

Fig. 3

a section, taken along the line III-III of Fig. 2,

Fig. 4

a section seen along the line IV-IV of FIG. 2

Fig. 5

a preferred variant to Fig. 3,

Fig. 6

a three-dimensional view of a simplified contact element according to a second embodiment of the invention, and

Fig. 7

a representation of a printed circuit board with the contact element of FIG. 6th

Fig. 1 shows a circuit board 20 on which a conductor 22 is located, which is usually made of tinned copper. Above the conductor track 22, three holes 24, 26, 28 are provided in Fig. 1, and below it two holes 30, 32nd

According to FIG. 2, the five legs 34, 36, 38, 40, 42 of a contact element 44 are pressed into these five holes 24 to 32. By pressing the contact element 44 is held in the desired position on the circuit board 20. The contact element 44 is usually made of a copper alloy, or of copper, brass or the like. The conductor track 22 is largely adapted to the shape of the contact element 44 in order to enable a large-area soldering.

As can be seen clearly from FIG. 4, the legs 34, 36, 38 preferably have an identical shape. For example, the leg 38 has a free end 37, and has a reduced width 39 in the region of this free end 37, so that it can be easily inserted and pressed into the opening 28 when the circuit board 20 is loaded. In its upper part in Fig. 4, the leg 38 has a width 41 which is dimensioned such that it must be pressed into the opening 28, d. H. its width 41 exceeds the diameter D (Fig. 1) of the bore 28, so that during assembly receives a press fit, which gives a good mechanical connection. The holes 24 to 32 are metallized at least at one end, z. B. with copper to get a good press-fit and thus a good mechanical and also electrically conductive connection.

As can be seen from FIGS. 2 to 4, the contact element 44 may have two legs 34, 36, 38 on its upper side in FIG. 2, and two legs 40, 42 on its lower side. All the legs are electrically and mechanically connected to a base part 46, which in FIG. 2 looks like an inverted U and has two legs 48, 50 and a base 52 which these thighs connects. But it can also be only one or two legs.

Between the legs 48, 50, a spring tongue 54 is punched out, which is formed integrally with the base 52 at its upper end in Fig. 2. The spring tongue 54 has at its left in Fig. 3 part 56, where it rises sharply and merges into a slowly sloping portion 58, which leads to a contact point 60 and from 62 slowly rises again, so that in Fig. 3 shows an insertion opening 64 on the right, into which a dash-dotted lines indicated sheet metal part 66 can be inserted, for. B. for electrical connection to a (not shown) motor to be controlled by the circuit board 20, or for connection to a power supply or with any device.

The base member 46 has left and right each have a highly curved cheek 70 and 72. The cheek 70 is formed on the leg 48, the cheek 72 on the leg 50. These cheeks 70, 72 serve as lateral guide members for the sheet metal part 66 during its assembly.

Assembly

Before pressing the contact element 44, the circuit board 20 is printed at the required locations with solder paste. Subsequently, the contact element 44 is pressed into the circuit board 20, wherein a portion of the solder paste in recesses 49 of the contact element 44 passes and is stored in these recesses.

After press-fitting, the electronic components (SMD components) are mounted in the usual way on the previously printed solder paste, and after this is done, the circuit board is transported through a reflow oven, where the soldering of all components takes place.

In the invention, therefore, only a single intermediate step is necessary, namely the pressing of the contact element 44. All other processes must also be performed for the SMD components, d. H. for the assembly of the contact element 44 only very small additional costs.

In Fig. 1 it should be noted that the conductor 22 is adapted to the shape of the contact element 44, as is apparent from a comparison of Figs. 1 and 2 directly. This achieves large-area soldering.

In order to prevent that the previously applied solder paste is pressed away completely laterally during the pressing of the contact element 44, 46 through recesses 49 are provided in the base in this part in which the solder paste is partially pressed so that when soldering in the reflow oven enough solder paste for Is available to get a proper solder joint. These recesses 49 thus serve as a reservoir for the solder paste.

The contact element 44, after its legs 34 to 42 were pressed into the holes 24 to 32 of the circuit board 20, soldered in the reflow oven in the usual way. In this case, solder 74 flows into the openings 24 to 32 and flows by capillary action also under the base part 46, whereby this is soldered to the conductor track 22 over a large area. As a result, an additional mechanical connection with the printed circuit board 20 is produced. Likewise, the connection arrangement 44 is electrically connected securely to the conductor track 22.

The sheet metal part 66 for the electrical connection can, for. B. have a width of 0.8 cm. It preferably has a recess into which a wart or tongue or the like provided on the spring tongue 54 engages during assembly in order to enable secure mechanical locking between the spring tongue 54 and the sheet metal part 66, which is also useful during assembly.

After insertion, the sheet metal part 66 is attached to two lateral areas, e.g. at the points 76, 78, welded by welding by means of a laser non-contact (so-called laser points). This makes it possible to produce the welded connection on an already equipped printed circuit board 20 without its electrical components being damaged or destroyed by external voltages. By welding you get a material connection from the contact element 44 to the sheet metal part 66, so a very safe and reliable electrical and mechanical connection.

FIG. 5 shows a variant of FIG. 3. Identical or equivalent parts as in FIG. 3 are therefore designated by the same reference numerals.

A disadvantage of Fig. 3 may be that during assembly of the contact element 44, a gap between this and the circuit board 20 is formed, which could hinder the formation of a secure solder joint. The reason is that the legs 34 to 42 in the right Angle down are bent, which inevitably creates a bending radius, which can cause the gap described during pressing.

The variant of FIG. 5 allows a full support of the contact element 44 on the circuit board 20. In this variant, the legs are first bent up and then bent by 180 °. This is illustrated by the example of the legs 34 'and 40'. The leg 34 'is bent at the point 57 in the upward direction, then makes a bend at 180 ° by 180 °, wherein the radius of this bend may possibly be made very small, and goes from there at 61 vertically downwards. The same shape, but mirror-image can be found in the leg 40 '.

Due to this configuration, the base part 46 (legs 48, 50 and base 52) can rest on the printed circuit board so that an excellent solder joint results in the reflow oven, because the solder reliably fills the entire gap between the contact element 44 and the conductor track 22 , Here, the recesses 49, which were described in Fig. 2, are very advantageous and are therefore used in the same way in the variant of FIG. 5.

Fig. 6 shows approximately a scale of 10: 1 a three-dimensional view of a contact element 80 which is constructed similar to the contact element 44 of FIG. 1 to 5, but only four legs has. It has a base portion 82 with two longitudinal legs 84, 86 connected on one side by a base 87. From the leg 84 two legs 88, 90 are bent and from the leg 86 two legs 92, 94th

Between the legs 84, 86, a resilient contact tongue 96 is punched out and shaped in the manner shown in order to insert an electrical conductor, for. As a flat metal part, and to securely hold this flat metal part in the inserted position.

7 shows the attachment of a metal strip 66 serving as an external electrical conductor to the contact element 80. The latter is fastened on a printed circuit board 20 in the manner described above, wherein the printed conductor 22 (see Fig. 1) is not shown here for the sake of simplicity.

As can be seen, the contact element 80 with its four legs 88, 90, 92, 94 in FIG soldered corresponding recesses of the circuit board. The sheet metal part 66 is inserted between the base part 82 and the resilient tongue 96. The latter has on its sheet metal part 66 side facing a wart 97, the hollow top in Fig. 7 is visible. The sheet metal part 66 has a corresponding (not shown) recess, and if it is inserted properly, the wart 97 engages in this recess and thereby holds the sheet metal part 66 captive firmly.

Subsequently, the sheet metal part 66 is welded in its designated in Fig. 7 with 100 area by laser spot welding to the base part 82. The same happens preferably also on the opposite side not visible in FIG. 7. In this way you get a very reliable electrical and mechanical connection that can be easily manufactured automated.

The attachment to a printed circuit board 20 is carried out in the same manner as described in FIGS. 1 to 5 for the first embodiment, d. H. by means of an interference fit in holes of the printed circuit board, as shown in Fig. 7, and in addition by corresponding solder joints. The legs 88, 90, 92, 94 may for this purpose have at their free ends a slightly reduced width to facilitate mounting in the holes of the circuit board.

1. a) Die Verbindung von der Leiterbahn zum Kontaktelement.
2. b) Die Verbindung vom Kontaktelement zum externen Leiter.

The connection of a conductor track of the printed circuit board to an external electrical conductor has two components:

1. a) The connection from the conductor to the contact element.
2. b) The connection from the contact element to the external conductor.

The connection component a) obtains its security by the combination of a press-fit operation, which causes predominantly a mechanical, but also an electrical connection, with a soldering process in which the low-resistance electrical connection is in the foreground, but also a mechanical connection is produced.

The connection component b) obtains its security by welding the flat conductor to the contact element, wherein the engagement of the conductor, and the spring force on the contact tongue, provide additional redundancy and facilitate assembly.

By the invention gives an electrical connection of great security, it allows to connect the trace of a circuit board safely and reliably with an external component in which high currents flow, for. B. with an electric motor. This secure and reliable connection is made possible by a press-fit connection between the printed circuit board and the contact element and by a solder connection to the conductor track 22, and by the non-contact welds 76, 78, as described in FIG. The assembly is extremely simple and can be easily automated, which is facilitated by the snapping between the sheet metal part 66 and spring tongue 54.

Naturally, many modifications and modifications are possible within the scope of the present invention.

Claims (12)

1. Arrangement with a circuit board (20) comprising at least one conductor track (22), and with a contact element (44) for contacting an electrical conductor (66) which serves for connection to this circuit board (20), which arrangement comprises the following features:

   in the area of a predetermined conductor track (22) the circuit board (20) has openings (24, 26, 28, 30, 32);

   the contact element (44; 80) has a base part (46; 82) and small legs (34, 36, 38, 40, 42; 88, 90, 92, 94) provided thereon for pressing into predetermined openings (24 to 32) in the circuit board (20);

   in the area of its base part (46; 82) the contact element (44; 80) is connected electrically to the predetermined conductor track (22) by a soldered connection (74);

   the contact element (44; 80) has a contact tongue (54; 95) which is articulated resiliently on the base part (46; 82) and designed for contacting the electrical conductor (66); the openings (24, 26, 28, 30, 32) in the area of the predetermined conductor track (22) are continuous openings;

   characterised in that pressing the small legs (34, 36, 38, 40, 42; 88, 90, 92, 94) into the predetermined openings (24 to 32) produces a mechanical connection and an electrical connection to the predetermined conductor track (22), and

   the contact element (44; 80) is connected to the electrical conductor by means of a welded connection (76, 78).
2. Arrangement according to claim 1, in which at least one lateral guide member (70, 72) is provided for the electrical conductor (66) on the contact element (44).
3. Arrangement according to claim 2, in which the lateral guide member (70, 72) is formed in one piece with the base part (46).
4. Arrangement according to one of the preceding claims, in which at least one part of the small legs (34 to 42) has a reduced breadth (39) in the area of the free end (38).
5. Arrangement according to one of the preceding claims, in which the electrical conductor (66) is slid in between the contact tongue (54) and the base part (46) and connected by a welded connection (76, 78) to at least one element of the entity, to which entity the base part (46) and the contact tongue (54) belong.
6. Arrangement according to claim 5, in which the welded connection (76, 78) is produced by laser welding.
7. Arrangement according to one of the preceding_claims, in which the electrical conductor (66) is embodied as a flat conductor.
8. Arrangement according to claim 7, in which the flat conductor (66) is designed for mechanical latching with the contact tongue (54; 96).
9. Arrangement according to claim 8, in which the contact tongue (54; 96) comprises a projection (97) and the flat conductor (66) is provided with an opening for engagement of this projection.
10. Arrangement according to one of the preceding claims, in which the contact element (44; 80) is provided with at least one opening (49) which is designed in the manner of a reservoir to receive soldering paste during the preparation for the soldering operation.
11. Arrangement according to claim 10, in which the at least one opening (49) is formed in an area of the contact element (44; 80) serving for areal soldering to the predetermined conductor track (22).
12. Arrangement according to one of the preceding claims, in which the connection between the base part and at least one small leg comprises a connecting part (59) which in a part area of the gap between the small leg (61) and the base part (70) comprises a gap to the circuit board (20).

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