Method and device for producing an electrically conductive connection between a conductor track and an electrical conductor

Abstract

The invention relates to a method for producing an electrically conductive connection between a conductor track (2) arranged on a substrate element (1) and an electrical conductor (3), in which the electrically conductive connection is made indirectly via a contacting element (4). According to the invention, during positioning and / or fixing of the contacting element (4) with respect to the substrate element (1) or a plastic component (5) accommodating the substrate element (1) via a first connecting section (4.1), an electrically conductive connection is established simultaneously between the contacting element (4) and the conductor track (2) via a second connecting section (4.2), which is designed as a spring arm. The invention further relates to a device for carrying out the method according to the invention.

Description

[0001] The invention relates to a method and a device for producing an electrically conductive connection between a conductor track arranged on a carrier element, in particular on a printed circuit board, and an electrical conductor, wherein the conductor may in particular be a connecting wire or a connecting strand. State of the art

[0002] Creating an electrically conductive connection between a conductor track mounted on a substrate and an electrical conductor often proves difficult. This is especially true when the electrically conductive connection between the conductor track and the electrical conductor is to be made via a solder joint and the substrate is a thin plastic circuit board. In such cases, there is a risk that the plastic will melt due to the high temperatures generated during soldering, causing the conductor track to detach from the circuit board.

[0003] The adhesion of the conductive trace to the substrate is generally based on the conductor material interlocking with the substrate's surface. To achieve such interlocking, the conductor material can be applied to the substrate by thermal spraying, particularly cold plasma spraying, laser structuring, or a jet process. Thermal spraying, in particular, causes the conductor particles to penetrate the substrate's surface because they impact it at high speed. However, even such interlocking of the conductor material with the substrate's surface cannot completely prevent the conductor from detaching from the substrate.This is especially true if the electrically conductive connection of the conductor track with an electrical conductor is to be made via a rigid connection, such as a soldered connection, since additional forces act on the conductor track in this case.

[0004] Therefore, alternative techniques for producing an electrical connection between a conductor track and an electrical conductor are known from the prior art, which, for example, provide an adhesive or plug connection instead of a soldered connection.

[0005] Furthermore, the electrical connection can be established indirectly via a separate contact element. This contact element can, for example, be a metallic contact pin or strip that is already integrated into the mold during the injection molding of the carrier element and partially encased in plastic, thus creating at least one exposed area. The conductor track can then be guided over this exposed area of ​​the contact pin or strip when applied to the carrier element, thereby establishing an electrical connection between the conductor track and the contact element. Subsequently, the contact element must be connected to the electrical conductor. Due to differing coefficients of thermal expansion and the associated stresses between the contact element and the carrier element, the connection must be made within a specific timeframe.However, cracks may form in the conductor track and / or the conductor track may detach.

[0006] US 2004 / 214455 A1 describes a base for electrical components. DE 10 2011 077589 A1 discloses contact elements, in particular designed as contact springs. JP 2014 / 072101 A shows a design for an electrical connection for a conductor located on a surface.

[0007] Based on the aforementioned prior art, the present invention aims to provide a method and a device for producing an electrically conductive connection between a conductor track arranged on a support element and an electrical conductor, which is easy to implement and places as little stress as possible on the adhesive bond between the conductor track and the support element.

[0008] To solve the problem, the method with the features of claim 1 and the device with the features of claim 3 are proposed. Advantageous embodiments of the invention can be found in the respective dependent claims. Disclosure of the invention

[0009] In the proposed method for producing an electrically conductive connection between a conductor track arranged on a support element and an electrical conductor, the electrically conductive connection is established indirectly via a contacting element. According to the invention, when positioning and / or fixing the contacting element with respect to the support element or a plastic component receiving the support element, an electrically conductive connection between the contacting element and the conductor track is simultaneously established via a second connecting section, which is designed as a spring arm, via a first connecting section.

[0010] Unlike a soldered connection, the spring arm does not create a rigid connection at the conductor track contact point. Therefore, no forces are introduced via the spring arm that could impair the bond between the conductor track and the carrier element. The spring arm enables a type of contact that even allows for relative movement of the conductor track with respect to the contact element, thus compensating for thermally induced changes in length. At the same time, the first connection section of the contact element ensures a permanently secure fit of the contact element within the carrier element or the plastic component that houses the carrier element.

[0011] The contacting element used in the inventive method therefore has at least two differently designed connection sections. This makes it possible to separate the functions of fastening and contacting, thus resolving the conflict between a permanently fixed connection on the one hand and a connection that allows relative movement on the other. Both fastening and contacting can be carried out in a single manufacturing step, so that no additional manufacturing step is required. Although the contacting element still needs to be connected to the electrical conductor after this manufacturing step, this connection can be made by means of a simple plug or crimp connection.

[0012] When positioning and / or fixing the contact element relative to the carrier element or the plastic component, the second connecting section of the contact element, designed as a spring arm, is preferably elastically deformed and pre-tensioned against the conductor track. The pre-tension of the spring element compensates for manufacturing and / or assembly-related tolerances. At the same time, vibrations, relaxations in the plastic, and / or thermally induced changes in length can be compensated for by the pre-tension of the spring arm. The pre-tension force acts primarily perpendicular to the longitudinal direction of the conductor track, so that essentially no forces are introduced via the pre-tension of the spring arm that would impair the adhesive bond between the conductor track and the carrier element.

[0013] When positioning the contacting element relative to the carrier element or the plastic component, the first connecting section is positively engaged with the carrier element or the plastic component. This positive engagement and / or interlocking connection secures the contacting element, fixing its position relative to the carrier element or the plastic component. The positive-locking connection is achieved via a plug-in, press-fit, and / or snap-fit ​​connection. For example, the first connecting section of the contacting element can have an interference fit—at least in part—within a recess formed in the carrier element or the plastic component to receive the first connecting section, thus enabling a positive-locking connection between the contacting element and the carrier element or the plastic component.Alternatively or additionally, a positive connection can be achieved via at least one undercut geometry formed on the first connection section of the contacting element.

[0014] Furthermore, it is proposed that in the inventive method, the contacting element is electrically connected to the electrical conductor via a third connection section, wherein the connection is made via a plug or crimp connection, as this is easy to implement. For a plug connection, the third connection section can be designed as a simple pin. For a crimp connection, the third connection section preferably has an end section that can be wrapped around the electrical conductor and plastically deformed by crimping.

[0015] The further proposed device for creating an electrically conductive connection between a conductor track arranged on a carrier element and an electrical conductor comprises a contacting element which, according to the invention, has a first connecting section for positioning and / or fixing the contacting element in relation to the carrier element or in relation to a plastic component receiving the carrier element, and a second connecting section for connecting the contacting element to the conductor track, wherein the second connecting section is designed as a spring arm. This means that the contacting element has at least two differently designed connecting sections, so that the functions of fixing and contacting are separated.The spring arm also enables contact that allows relative movement of the conductor track with respect to the contacting element, making the contacting element particularly suitable for carrying out the method according to the invention. Regarding the advantages, reference can be made to those already mentioned in connection with the method.

[0016] According to a preferred embodiment of the device according to the invention, the second connecting section of the contacting element, designed as a spring arm, has a contact area that is convexly curved with respect to the conductor track. Contact via the convexly curved contact area reduces the contact surface of the spring arm against the conductor track, allowing the conductor track and spring arm to move more easily relative to each other. Preferably, the second connecting section is bent in an S-shape to create the convexly curved contact area. The spring arm can thus be easily formed by the contacting element itself by bending a free-standing strip-shaped area or section into an S-shape. Preferably, the contacting element has a contact shoulder for contact with the support element or with the plastic component that receives the support element.The position of the contact shoulder allows for the definition of a maximum insertion or press-fit depth of the contacting element in relation to the carrier element or the plastic component. The contact shoulder is therefore preferably located adjacent to the first connection section of the contacting element.

[0017] Furthermore, the first connecting section of the contacting element has at least one undercut geometry for a positive-locking connection with the carrier element or the plastic component that receives the carrier element. This at least one undercut geometry enables a positive-locking connection between the contacting element and the carrier element or the plastic component, thus ensuring the most durable possible fastening of the contacting element. For example, the first connecting section can be designed as a strip with locking lugs on both sides, so that, viewed from above, the first connecting section resembles a Christmas tree. The locking lugs cause the first connecting section to interlock with the carrier element or the plastic component.

[0018] Furthermore, it is proposed that the contacting element has a third connection section for connecting to the electrical conductor, wherein the third connection section is designed as a pin. Designing the third connection section as a pin enables a simple plug-in connection between the contacting element and the electrical conductor.

[0019] Furthermore, a crimp connection can be achieved using the pin by placing it around the electrical conductor and plastically deforming it by crimping. Advantageously, the contacting element of the device according to the invention is a stamped / bent part made from a sheet of metal. The contacting element is thus particularly easy and cost-effective to manufacture. In particular, the second connecting section, designed as a spring arm, can be easily cut and formed by stamping and bending the sheet of metal.

[0020] Preferred embodiments of the device according to the invention, which enable the implementation of the method according to the invention, are explained in more detail below with reference to the accompanying drawing. These show: Fig. 1 a schematic longitudinal section through a device according to the invention in electrically conductive connection with a conductor track arranged on a support element, Fig. 2 a schematic longitudinal section through a modified embodiment of the device of Fig. 1 , Fig. 3 a schematic longitudinal section through the device of the Fig. 1 , but rotated by 90°, Fig. 4 a schematic longitudinal section through the device of the Fig. 1 analogous to Fig. 1 , however with a modified support element, Fig. 5 a schematic longitudinal section through a device according to the invention in a second preferred embodiment, Fig. 6a schematic longitudinal section through the device of the Fig. 5 , but rotated by 90°, Fig. 7 a schematic longitudinal section through a device according to the invention in a third preferred embodiment and Fig. 8 a schematic longitudinal section through a device according to the invention in a fourth preferred embodiment. Detailed description of the drawings

[0021] The one in Fig. 1The device according to the invention, as illustrated, for producing an electrically conductive connection between a conductor track 2 arranged on a support element 1 and an electrical conductor 3, comprises a contacting element 4 in the form of a simple stamped / bent part made from a sheet metal part. The contacting element 4 has a first connecting section 4.1, which serves to fasten the contacting element 4 in the support element 1. From the plane of the first connecting section 4.1, an S-shaped second connecting section 4.2 in the form of a spring arm is bent outwards, which serves to contact a conductor track 2 arranged on the support element 1. The contact is effected via a contact area 6, which is convexly bent with respect to the conductor track 2.

[0022] Extending from the first connection section 4.1, the contacting element 4 forms a third connection section 4.3 in the form of a simple pin, which serves for connection to an electrical conductor 3. The connection can be made, in particular, via a plug connector.

[0023] Alternatively, in the Fig. 2 A crimp connection of the contacting element 4 with an electrical conductor 3 is shown. The electrical conductor 3 is formed in this case by a connecting cable, around which the third connecting section 4.3 of the contacting element 4 is placed and electrically connected by crimping.

[0024] Again Fig. 3As can be seen, the first connecting section 4.1 of the contacting element 4 can be designed as a flat strip with undercut geometries 8 arranged on both sides, which can be brought into a snap-fit ​​engagement with the support element 1 when the first connecting section 4.1 is inserted into a recess 9 of the support element 1. The geometries 8 prevent the first connecting section 4.1 from being pulled out of the recess 9 under tensile stress.

[0025] The Fig. 4 is a further education course offered by those in the Figures 1 to 3The illustrated embodiment of a device according to the invention can be seen in the illustration. In this case, the device according to the invention also comprises the support element 1 with the conductor track 2 applied thereto. The support element 1 and the conductor track 2 are provided with a chamfer 10, which causes an elastic deformation, in particular a bending, of the second connecting section 4.2, designed as a spring arm, when the first connecting section 4.1 is inserted into the recess 9 of the support element 1.

[0026] Another preferred embodiment of a device according to the invention is described in the Fig. 5As shown, the carrier element 1 simultaneously forms a plug socket 11, which surrounds the third connection section 4.3 of the contacting element 4. The insertion or press-fit depth of the first connection section 4.1 in the carrier element 1 determines the preload of the second connection section 4.2, designed as a spring arm, with respect to the conductor track 2. This means that the spring arm in the device of Fig. 5 is brought perpendicularly to the longitudinal direction of conductor track 2. Accordingly, a chamfer 10, as in the Fig. 4 shown, omitted.

[0027] The Fig. 6It can be seen that the first connecting section 4.1, which in this case directly adjoins the third connecting section 4.3, can again have undercut geometries 8 in order to permanently secure the contacting element 4 in the carrier element 1. The insertion or press-fit depth of the contacting element 4 in the carrier element 1 is determined by a contact shoulder 7 adjacent to both sides of the first connecting section 4.1.

[0028] A modification of the embodiment of Figures 5 and 6 is in the Fig. 7 The connector socket 11 is formed by a separate plastic component 5, which also houses the support element 1. The support element 1 can therefore be a simple printed circuit board. The contact element 4 is attached to the plastic component 5.

[0029] A modification of the embodiment of Figures 1 to 3 or the Fig. 4 is the Fig. 8The carrier element 1 is also housed in a separate plastic component 5, which simultaneously serves to attach the contact element 4. The carrier element 1 is again designed as a simple printed circuit board. To facilitate bending or sliding the second connecting section 4.2, designed as a spring arm, onto the conductor track 2, the plastic component 5 has a chamfer 10.

Claims

1. Method for producing an electrically conductive connection between a conductor track (2) arranged on a carrier element (1) and an electrical conductor (3), in which the electrically conductive connection is produced indirectly via a contacting element (4), characterized in that, when positioning and / or fixing the contacting element (4) in relation to the carrier element (1), or to a plastic component (5) accommodating the carrier element (1), via a first connection portion (4.1), an electrically conductive connection of the contacting element (4) to the conductor track (2) is simultaneously produced via a second connection portion (4.2) in the form of a spring arm, wherein the contacting element (4) is connected electrically conductively to the electrical conductor (3) via a third connection portion (4.3), wherein the connection of the contacting element (4) to the electrical conductor (3) is produced via a plug-in or crimped connection, so that the functions of fastening and contacting are separated, wherein the first connection portion (4.1) provides for the fastening of the contacting element (4) in the carrier element (1) or in the plastic component (5) and the second connection portion (4.2) and the third connection portion (4.3) respectively provide for the electrical contacting of the contacting element (4) with the conductor track (2) and with the electrical conductor (3), wherein, when positioning the contacting element (4) in relation to the carrier element (1) or the plastic component (5), the first connection portion (4.1) is connected in a form-fitting manner to the carrier element (1) or the plastic component (5), wherein the form-fitting connection is produced via a plug-in, press-fit and / or latching connection.

2. Method according to Claim 1, characterized in that, when positioning and / or fixing the contacting element (4) in relation to the carrier element (1) or in relation to the plastic component (5), the second connection portion (4.2) of the contacting element (4) in the form of a spring arm is deformed elastically and is pre-stressed in relation to the conductor track (2).

3. Device for producing an electrically conductive connection between a conductor track (2) arranged on a carrier element (1) and an electrical conductor (3), comprising a contacting element (4), wherein the contacting element (4) has a first connection portion (4.1) for positioning and / or fixing in relation to the carrier element (1) or in relation to a plastic component (5) accommodating the carrier element (1) and has a second connection portion (4.2) in the form of a spring arm for connection to the conductor track (2), wherein the contacting element (4) has a third connection portion (4.3) for connection to the electrical conductor (3), characterized in that the third connection portion (4.3) is in the form of a pin for producing the connection via a plug-in or crimped connection, wherein the contacting element (4) optionally has an abutment shoulder (7) for abutment against the carrier element (1) or for abutment against the plastic component (5) accommodating the carrier element (1), and wherein the first connection portion (4.1) of the contacting element (4) has at least one undercut geometry (8) for form-fitting connection to the carrier element (1) or to the plastic component (5) accommodating the carrier element (1).

4. Device according to Claim 3, characterized in that the second connection portion (4.2) of the contacting element (4) in the form of a spring arm has a contacting region (6) which is bent convexly in relation to the conductor track (2), wherein preferably, for producing the convexly bent contacting region (6), the second connection region (4.2) is bent in an S-shaped manner.

5. Device according to either of Claims 3 and 4, characterized in that the contacting element (4) is a stamped and bent part produced from a metal sheet.

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