DE102009027707A1 - Method for connecting an enameled wire to a printed circuit board - Google Patents

Abstract

The present invention relates to a method for connecting an enameled wire (5) to a printed circuit board (2), comprising the steps of: stripping an end region (5a) of the enameled wire (5), providing an elastic conductive adhesive (6), arranging the stripped end region (5a ) of the enameled wire on the printed circuit board (2) and fixing the stripped end region (5a) to the printed circuit board by means of the elastic conductive adhesive.
Furthermore, the invention relates to a printed circuit board assembly, comprising a printed circuit board (2) having a through hole (7), a conductive via (8) disposed in the through hole (7), an insulated wire component (3) having a stripped end portion (5a) of the wire, and a conductive adhesive disposed in the via (8) surrounding the stripped end region (5a) and filling free regions in the via (8) to provide a conductive connection between the end region (5a) and the via element (5a). 8), wherein the conductive adhesive (6) is elastic.

Description

State of the art

The The present invention relates to a method for connecting a insulated wire (enameled wire) with a printed circuit board and a Circuit board assembly with a printed circuit board and an insulated one Wire-containing component.

Out the prior art is known, enamel-insulated copper wires of Coils or armature windings with the aid of metal contact pieces as an interface to contact between the copper wire and the circuit board. in this connection the PCB contact and the copper wire are not directly together connected but over the metallic contact piece. This technique has basically proven, However, it is relatively expensive, since the metallic contact pieces for Fixing must be kept in position. After a stripping of the enameled wire, usually in a hot Lotbad, the enameled wire to the contact piece and the contact piece to the Contact soldered to the circuit board. In particular, tin-plated enamelled wires however, they become less due to the high temperature requirements often used.

Disclosure of the invention

The inventive method with the features of claim 1, in contrast, has the advantage that it a direct contact of an insulated wire, hereinafter referred to as Enamelled wire, on a circuit board allows. This allows in particular the high accuracy requirements required in the prior art when using additional contact pieces be avoided. Furthermore, by direct contacting between the paint wire and the PCB a space reduction of the connection be achieved. This is inventively achieved by that a stripping of an end portion of the enameled wire stripped End region is arranged on the circuit board and by means of an elastic Conductive adhesive is fixed to the circuit board. Due to the elasticity of the conductive adhesive also becomes a compensation function when relative movements occur between the enameled wire and the circuit board allows. This can in particular the contact point are mechanically relieved. Furthermore, by the elasticity the Leitklebers also existing dimensional variations of the components be balanced, so that a high production quality of the connection between enameled wire and printed circuit board is achieved.

The under claims show preferred developments of the invention.

Preferably the printed circuit board has a passage opening with a through-connection and the stripped end portion is passed through the through hole. hereby Is it possible, that a Leitkleben the enameled wire in a Throug Hole technology (THT) allows and a particularly secure connection between the stripped Enameled wire and the circuit board is reached.

Especially Preferably, the via is made of a tin-containing Material made or complete made of tin. this makes possible a particularly cost-effective Contacting.

Further Preferably, the enameled wire is a copper enameled wire.

According to one Another preferred embodiment of the invention is the stripped End portion of the enameled wire is a straight wire end piece or the end portion provided as a winding around a pin. In the presence of a through hole is the End region preferably completely through the passage opening carried out. Alternatively, the stripped end portion of the enameled wire is on a plastic dome arranged or arranged on a sacrificial dome, which before fixing is removed by means of the conductive adhesive, wherein when using a Through opening the stripped end portions are also completely passed through the passage opening.

Of the elastic conductive adhesive preferably has a modulus of elasticity in a range of 1 MPa to 5000 MPa, preferably 3 MPa. In particular, the elastic conductive adhesive must compensate for the different Provide thermal expansions. An expansion coefficient of the conductive adhesive should be a Provide compensation in the temperature range of -40 ° to + 150 ° C to provide a mechanical and electrical damage Avoid contact between copper wire and PCB.

Further Preferably, the conductive adhesive has one or more metals with one lower melting point. Preferably, the conductive adhesive a solvent on.

Around a very thorough one To allow stripping of the enameled wire, the end portion of the Enameled wire preferably stripped by means of induction stripping.

The invention further relates to a printed circuit board assembly, comprising a printed circuit board with a through hole and a Durchkontaktierungselement and an insulated wire on pointing component, in particular a coil or a winding. The insulated wire has a stripped end region, which is arranged in the through-connection element and is fixed by means of an elastic conductive adhesive. In this case, the elastic conductive adhesive provides for the electrical connection between the stripped end region and the feedthrough element. The induction stripping is preferably carried out in such a way that a wire region to be stripped is heated in an electromagnetic alternating field, the insulation becoming brittle due to the heating of the wire arranged in the alternating field, and a subsequent removal of the brittle insulation from the wire. The removal can be done for example by means of a pressurized gas and / or mechanical deformation and / or by brushing or grinding or milling.

The inventive technique especially with control units for motor vehicles, z. B. control devices for anti-lock braking systems or electronic stability programs, be used. Also when contacting printed circuit boards for ignition coils or sensors is an application possible.

The inventive method is particularly suitable for bonding of non-precious surfaces, what So far in the prior art was not possible. Normally, surfaces must be used whose oxide layers have the same conductivity as that Base material. However, in particular by the elastic conductive adhesive on a surface refinement the contact partner and the via are omitted and base surfaces such as B. copper or tin are directly connected by the conductive adhesive. This results in a very high cost savings.

drawing

following become preferred embodiments the invention with reference to the accompanying drawings in Detail described. In the drawing is:

1 a schematic view of a connection between a paint wire and a printed circuit board according to a first embodiment of the invention,

2 a schematic view of a connection between a paint wire and a printed circuit board according to a second embodiment of the invention,

3 a schematic view of a connection between an enameled wire and a printed circuit board according to a third embodiment of the invention, and

4a . 4b Representations of a schematic view of a connection between a enameled wire and a printed circuit board according to a fourth embodiment of the invention,

Preferred embodiment of the invention

The following is with reference to 1 a method for connecting a paint wire according to a first preferred embodiment of the invention described in detail.

1 shows a circuit board assembly 1 comprising a printed circuit board 2 and a coil 3 which are electrically connected to the circuit board 2 connected is. The sink 3 includes a copper enameled wire 5 at which an end area 5a was stripped by an induction process. The end area 5a gets on the coil 3 from a spool dome 4 brought out in a straight line.

In the circuit board 2 is a passage opening 7 with a via element 8th provided, wherein the feedthrough element 8th the walls of the passage opening 7 completely covered and also still on a top and a bottom of the circuit board 2 the areas around the passage opening 7 covered in a ring. The via element 8th is connected to at least one conductor track of the printed circuit board.

The stripped end area 5a is how out 1 can be seen, completely through the passage opening 7 the circuit board 2 through put. The end area 5a is here by means of an elastic Leitklebstoffs 6 in the via element 8th fixed. The conductive adhesive 6 has a certain elasticity in order to be able to compensate in particular for manufacturing-related dimensional deviations on the components.

Thus, according to the invention, the enameled copper wire is directly connected to the printed circuit board 2 without the use of additional Kontaktierungsstücken o. Ä. Connected. As a result, the method according to the invention can be carried out very quickly and inexpensively. Should be relative movements between the circuit board 2 and the coil 3 These can additionally occur due to the coil dome 4 exposed area of the enameled wire. The use of the elastic conductive adhesive also makes it possible to dispense with high accuracy requirements, which are necessary in the prior art. Also, when using a conductive adhesive for non-precious surfaces (such as copper or tin) processes for surface finishing of the contact partners can be saved, so cost the process particularly can be carried out conveniently.

The end area 5a of the copper enamel wire was preferably stripped by means of an induction process, whereby a very high Strisolierqualität can be achieved and the stripped end 5a can be easily wetted with the conductive adhesive. Thus, a secure electrical connection between the end region 5a and the circuit board can be obtained without using an additional contact piece.

2 shows a circuit board assembly according to a second embodiment of the invention, wherein the same or functionally identical parts are denoted by the same reference numerals as in the first embodiment. How out 2 can be seen, the second embodiment substantially corresponds to the first embodiment, in addition to the coil dome 4 another pin 9 is arranged. The stripped end area 5a is about the pin 9 wound. How out 2 is apparent, is a symmetrical, formed with a substantially cylindrical cladding region winding around the pin 9 wound. As a result, in particular, the contact surface between the end region 5a and the conductive adhesive 6 enlarged, so that an even safer contact can be achieved. Furthermore, by the wound, stripped end portion 5a a space to be filled with conductive adhesive in the via element 8th reduced, so that the amount of conductive adhesive used 6 can be reduced. Otherwise, this embodiment corresponds to the previous embodiment, so that reference can be made to the description given there.

3 shows an alternative circuit board assembly according to a third embodiment of the invention, in turn, the same or functionally identical parts are denoted by the same reference numerals as in the preceding embodiments. The third embodiment corresponds essentially to the second embodiment, in contrast to the end region 5a of the enameled wire 5 different at the pin 9 is arranged. How out 3 is apparent, is the end region 5a parallel to the pin 9 arranged and through one at the free end of the pins 9 formed recess passed. This will give a better fixation of the end area 5a reached at the pin. As in 3 is apparent, is the end region 5a while essentially U-shaped arranged on the pin. Otherwise, this embodiment corresponds to the previous embodiment, so that reference can be made to the description given there.

The 4a and 4b show a circuit board assembly 1 according to a fourth embodiment of the invention, again identical or functionally identical parts are denoted by the same reference numerals as in the preceding embodiments. The fourth embodiment substantially corresponds to the third embodiment, wherein instead of the pin of the third embodiment in the fourth embodiment, a sacrificial dome 10 at the coil dome 4 is arranged. How out 4a is apparent, is the end region 5a at the sacrificial dome 10 arranged by crossing the free end of the sacrificial dome 10 is laid. Before fixing the end area 5a in the via element 8th by means of the conductive adhesive 6 becomes the sacrificial dome 10 removed what's in 4b indicated by the arrow A. Subsequently, the end area 5a in a known manner by means of the conductive adhesive in the circuit board 2 fixed. By using the sacrificial dome 10 is the end area 5a while off-center in the passage opening 7 in the circuit board 2 arranged. This can also lead to a direct contact between the stripped end region 5a and the via element 8th come, so that an even better contact is possible. Otherwise, this embodiment corresponds to the previous embodiments, so that reference can be made to the description given there.

Claims (10)

Method for connecting an enameled wire ( 5 ) with a printed circuit board ( 2 ), comprising the steps of: stripping an end region ( 5a ) of the enameled wire ( 5 ), - providing an elastic conductive adhesive ( 6 ), - arranging the stripped end region ( 5a ) of the enameled wire on the printed circuit board ( 2 ), and - fixing the stripped end region ( 5a ) on the circuit board by means of the elastic conductive adhesive. Method according to claim 1, characterized in that the printed circuit board ( 2 ) a passage opening ( 7 ) with a via element ( 8th ) and the end region ( 5a ) of the enameled wire through the via element ( 8th ) and the elastic conductive adhesive ( 6 ) the area between the stripped end region ( 5a ) and the via element ( 8th ). Method according to claim 2, characterized in that the via element ( 8th ) Contains tin or is made entirely of tin. Method according to one of the preceding claims, characterized in that the wire of the enameled wire is made of copper or a Copper-containing material is made. Method according to one of the preceding claims, characterized in that the abi solitary end area ( 5a ) is provided as a straight wire end piece or the stripped end portion ( 5a ) as a winding around a pin ( 9 ) is provided or the stripped end portion ( 5a ) on a pin ( 9 ) is arranged substantially parallel to this or the stripped end region ( 5a ) at a sacrificial dome ( 10 ), which is removed before fixing. Method according to one of the preceding claims, characterized in that the conductive adhesive ( 6 ) has a modulus of elasticity in a range of 1 MPa to 5000 MPa, preferably 3 MPa. Method according to one of the preceding claims, characterized in that the conductive adhesive ( 6 ) Has metals with a lower melting point. Method according to one of the preceding claims, characterized characterized in that the conductive adhesive comprises a solvent. Method according to one of the preceding claims, characterized in that the end region ( 5a ) is stripped by means of induction stripping. Circuit board assembly comprising: - a printed circuit board ( 2 ) with a through hole ( 7 ), - a conductive via element ( 8th ), which in the through hole ( 7 ), - an insulated wire component ( 3 ) with a stripped end region ( 5a ) of the wire, and - a conductive adhesive ( 6 ), which in Durchkontaktierungselement ( 8th ) and the stripped end region ( 5a ) and free areas in the via element (FIG. 8th ) to make a conductive connection between the end region ( 5a ) and the via element ( 8th ), the conductive adhesive ( 6 ) is elastic.

Images