DE102012211760A1 - Method for producing carrier of electric component i.e. door lock, for motor vehicle, involves arranging strip conductors, and overmolding conductors with insulation material, so that electrical pads are protected and/or insulated - Google Patents

Abstract

The method involves arranging electrical strip conductors (2) on an electrical isolating base part (1). An electric component (3) e.g. doorlock, is fixed for an electrical contact (4) to the strip conductors. The strip conductors are overmolded with a foamed insulation material such as foamed plastic, so that electrical pads (5) are protected and/or insulated. The electrical strip conductors are arranged in the base part and partly overmolded in an injection molding process. Support elements for electric components are provided in the injection molding process. An independent claim is also included for an electrical component carrier.

Description

The invention relates to a method for producing an electrical component carrier according to the preamble of claim 1 and an electrical component carrier for a motor vehicle according to the preamble of the independent claim.

An electrical component carrier is a self-supporting component with a base part comprising a housing and electrical conductor tracks inserted into the housing, which have basically been punched out of a metal sheet. The material of the conductor tracks is so thick and therefore stable that conductor ends can serve as contact pins. In addition, the material is basically flexible, so that conductor ends can be bent in order to make contact in a desired direction. Basically, the conductor tracks are made of metal and are in particular 0.1 mm to 1 mm thick.

To the electrical connections of such a conductor track unit electrical components - also called electrical or electronic components - connected - such as switches, micro-switches, detectors or electric motors. Such electrical components can be found for example in a lock, in particular door lock of a motor vehicle.

A lock for motor vehicles in the sense of the present invention basically comprises a rotary latch and at least one pawl with which a rotation of the rotary latch in the opening direction can be blocked.

For production, for example, conductor tracks are first punched out of a metal sheet and, if necessary, additionally prepared by bending, for example, for the provision of contact lugs and / or drilling. The thus prepared conductor tracks, which may still have connecting webs are then inserted into an injection mold for producing an electrical component carrier. Subsequently, insulating material is injected into the tool in a first step for the purpose of fixing the conductor tracks. This step is called pre-spraying or pre-spraying. Then connecting webs - if present - are separated between the tracks. Subsequently, the tool can be filled by injecting insulating material in the intended manner to form the electrical component carrier and thus protect printed conductors against adverse external influences.

Contact lugs protrude from the insulating material in order to contact electrical components such. B. to be connected to a microswitch. The projecting tabs then form the electrical connections of the electrical component carrier. The insulating material is preferably a thermoplastic.

If now the electrical component carrier to be connected to an electrical component, the component is used at the designated location and soldered its electrical contacts with the associated electrical tabs of the over-molded conductor track or connected in a comparable manner. For example, a microswitch is used so that its contacts can be soldered to the above contacts of the conductor tracks.

To the resulting contact points such. B. also to protect solder joints, they are encapsulated in a separate process step with an insulating material, so that a corresponding potting encases this. This basically requires a separate process step in the production and contacting of an electrical component carrier. It should be noted that the contact must be accessible to an encapsulation, that is, the contact point must be suitable to be encapsulated. For example, contact points of microswitch and trace are suitable to be encapsulated. A measure of an overmolding capability is the flow of current through the pad, depending on the level of current flow, a pad is suitable for an encapsulation or not.

From the publication EP 1 357 774 A1 a method for producing a plastic-coated conductor structure is known in which the conductor structure is inserted into an injection mold and at least one electronic or electrical component is fixed to the conductor structure. In this case, the conductor structure including the electronic component is encapsulated in a plastic injection process. In order to protect the electronic components, the electronic component is provided with a sheath. However, the additional provision of a wrapper is technically complex and not satisfactory from the required space.

From the publication EP 1 170 110 A1 a method for producing a plastic-coated conductor structure of an electrical circuit unit is known in which at least one electronic component is fixed to a conductor structure, for example by soldering, and in which the partially over-molded conductor structure is encapsulated in a further plastic injection process, including the electronic component. The fixation of the electronic component is intended to prevent a displacement during the plastic injection process.

Performing a plastic injection process is fundamentally associated with the problem that a relatively high pressure for spraying is required. Electrical or electronic components such. B. microswitches can not be molded around easily due to their pressure or temperature sensitivity, so that damage to the electrical or electronic components is not excluded. The resulting malfunction of the components are not tolerable for efficient production, in particular mass production.

Unless otherwise stated below, the abovementioned features may be combined as desired individually or in any combination with the subject matter of the invention described below.

It is an object of the invention to further develop the production of an electronic component carrier.

The object of the invention is achieved by a method having the features of claim 1 and by an article having the features of the independent claim. Advantageous embodiments emerge from the subclaims.

According to the claimed method, at least one electrical component is fixed to the conductor track for electrical contacting, and then the conductor tracks are encapsulated with a foamed or foaming insulating material, preferably foamed or foaming plastic, in such a way that electrical contact points are protected or insulated.

Electrical contact points are basically the areas that arise in an electrical contacting of the conductor with the electrical components.

It is essential to recognize that the encapsulation of a foamed insulation material prevents damage to the electrical or electronic components. The pressure during encapsulation of a foamed insulating material such as foamed plastic is much lower due to the foaming. In particular, this can be a process-related emphasis omitted in the conventional plastic injection molding process thermoplastic thermoplastics, since the mold is essentially formed by the foaming. The temperature during the encapsulation of the foamed plastic material can be advantageously lowered. Damage to the electrical or electronic components during manufacture can therefore be reliably prevented.

In contrast to the above-described prior art omitted in the proposed method, a separate process step of encapsulation, for example by means of a potting compound, so that the manufacturing effort is reduced overall. In other words, it is possible to dispense with pre-encapsulating the printed conductors. The protection of the contact between electrical components and the tracks in an electronic component carrier is thus manufactured in an efficient manner.

In one embodiment of the invention, the electrical conductor tracks are almost completely enveloped during encapsulation with the foamed insulating material. Almost means in this case, in the electrical component carrier, a region of the conductor tracks is provided, which serves for an external electrical contacting of the electrical component carrier, such a region remains correspondingly free in the encapsulation with the foamed insulating material. The complete covering of the tracks allows complete sealing and protection against damaging influences such as moisture or dust particles. The encapsulation with the foamed insulating material in this case corresponds to a final encapsulation of the electrical component carrier for the protection of exposed printed conductors. A separate process step for a final encapsulation of the conductor tracks is therefore no longer required, so that a rational mass production of an electrical component carrier is made possible.

In one embodiment of the invention, initially arranged in the base part electrical conductor tracks are at least partially encapsulated in an injection molding process to obtain a pre-injection. The pre-injection is preferably carried out with an insulating material such as plastic in an injection molding process. The printed conductors can be prefixed in this way already in the base part. The Endumspritzung can then take place advantageously with the encapsulation of the foamed insulating material. The pre-fixing of the tracks ensures an accurate and reliable positioning of the tracks in the base part. In the further course of production, the electrical components can consequently also be fixed more easily to the already prefixed conductor tracks for electrical contacting.

In a preferred embodiment, one or more support elements for electrical components are provided in the injection molding at the same time.

The support elements are preferably provided as supports or recordings in the injection molding with, so injected. The provision of support elements contributes on the one hand to the improved positioning of the electrical components and allows in a configuration as a positive and / or non-positive recording at the same time also a fixation of the electrical components. It is particularly advantageous to design the support element in such a way that the fixation in or on the support element simultaneously produces electrical contact between the electrical component and the conductor by, for example, bringing the projecting contact lugs of the electrical component into contact with the corresponding contact regions of the electrical conductors. Such a configuration of the support element allows in one step a fixation and electrical contacting of the electrical component. A separate step for fixing the electrical component to one or more conductor tracks, for example by soldering, can thus be omitted. Subsequently, it is only necessary for a protection of the electrical contact points, according to the proposal to overmold a foamed insulating material.

Particularly advantageously, a thermoplastic is used for the foamed insulating material, which was foamed in particular with a physical or chemical foaming agent or foams during the extrusion coating. Preferred is a physical process for foaming thermoplastics by means of blowing agents such as nitrogen or carbon dioxide, also known as MuCell process. It can thus produce moldings with microcellular foam structure. Advantageously, this contributes to a delay of the molded parts thus formed is minimized. It produces molded parts with high dimensional stability. In addition, weight or material is saved and the cycle time during production is shortened, which allows a rational production. It is also possible to use a thermoplastic foam casting process (TSG) with chemical blowing agents in an advantageous manner.

In a preferred embodiment, the overmolded foamed insulating material forms a sheath, preferably with a wall thickness of at least 1 mm, particularly preferably at least 2 mm, in order to protect suitably against external influences. In addition to the electrical contact points, the sheath can also encase the electrical conductor tracks and possibly the electrical components. Advantageously, the sheath is designed to be dense in order to prevent damage to the enveloped parts due to external influences such as moisture or dust particles. Furthermore, the sheathing or sheathing by means of the foamed insulating material has damping, in particular sound-damping properties, which are particularly advantageous for the use of a so-formed electrical component carrier in motor vehicles.

Preferably, a micro-component such as a micro-switch is provided as the electrical component. In particular, the dimensions of the electrical component are not greater than 30 mm, more preferably not greater than 20 mm. Micro devices such as microswitches are particularly sensitive to pressure and temperature deviations. Would like the state of the art (see. EP 1 170 110 A1 ) known a conventional injection molding used for encapsulation of the microswitch, the microswitch would be destroyed due to the high pressures during injection molding. Due to the effects described above, the proposed method can advantageously be carried out using microcomponents, in particular microswitches, without risking damage to the installed electrical components as a result of impermissible pressures and / or temperatures.

In order to achieve an exact, stable positioning or fixation of the electrical conductor tracks and possibly the electrical components in the base part, the base part is formed in a further embodiment for a positive or non-positive reception. For this purpose, the base part can be designed with depressions and walls, into which electrical conductor tracks and, if appropriate, electrical components can be accommodated expediently.

In a further embodiment, the electrical components are fixed to protruding or recessed contact points, in particular contact lugs of the conductor tracks. This facilitates the electrical contacting of the electrical components with the conductor tracks. The fixation of the electrical components to the conductor track is preferably carried out by soldering, gluing, welding and / or cold pressing. The base part of the electrical component carrier can advantageously be designed as a housing or as a component of the housing. In particular, the housing may be provided in a motor vehicle, for example as part of a motor vehicle lock, which is able to accommodate further components of the motor vehicle lock in the housing.

According to another teaching, which has independent significance, an electrical component carrier for a motor vehicle is claimed, which is preferably produced by the method described above. In this electrical component carrier, at least one electrical component, in particular a microswitch, is in electrical contact with electrical conductor tracks. Furthermore, the electrical contact points are encased by a sheath with foam structure such that they are protected or isolated.

It is essential that the electrical contact points are enveloped by a sheath with a foam structure. The foam structure is preferably by a physical method for Foams of thermoplastics such as the MuCell process have been produced. The foam structure allows the production of stress-free molded parts, so that not only a reliable protection of the electrical contact points is possible, but also contribute to the stability. Furthermore, such a foam structure has damping, in particular sound-damping properties, so that such electronic component carriers are particularly suitable for use in motor vehicles, especially in noise-critical applications such as motor vehicle locks or locks.

All statements made on the above method which are suitable for describing the configuration of the electronic component carrier apply correspondingly to this further teaching.

The invention will be explained in more detail below with reference to exemplary embodiments. It shows:

1 a schematic representation of an electrical component carrier with micro switch.

The embodiments relate to an electrical component carrier with microswitch and its manufacture. The electrical component carrier can advantageously be installed in a motor vehicle, in particular as a component or housing of a motor vehicle lock.

For the production of electrical conductor tracks, which were preferably punched out of a sheet in the form of punched grids, inserted and pre-molded in a tool of a semifinished product for an electric component carrier, so that a pre-molded part is formed. If necessary, track connections such as webs are separated in an intermediate step. An electrical component such as a microswitch is fixed to the housing of the pre-molded part in such a way that an electrical contact is made with the conductor tracks. Preferably, electrical contacts of the microswitch are soldered to corresponding areas of the conductor tracks, for example contact lugs formed thereon, in order at the same time to enable fixation and contacting. In addition to soldering, gluing, welding, cold pressing or comparatively well-known methods for producing an electrical contact are also possible.

In order to obtain protection or insulation of the resulting electrical contact points such as solder joints, the pre-molded part is inserted in addition to a fixed micro-switch in an injection mold. The electrical traces are then overmolded with a foaming insulating material, which has preferably been processed by means of the MuCell method, in such a way that the electrical contact points are protected or insulated. The use of a foaming process, in particular of the MuCell process eliminates the high pressure that arises in the conventional injection molding process such as plastic injection molding. This reliably prevents damage to sensitive electrical components such as microswitches.

In order to simplify the manufacture of an electrical component carrier, the electrical conductor tracks in the pre-molded part are completely enveloped during encapsulation, apart from possibly existing regions of the conductor tracks which are provided for external electrical contacting of the electrical component carrier, such as a plug. The encapsulation by means of a foaming process then simultaneously represents a final encapsulation of the electrical component carrier, so that a rational production is made possible.

In the production it is also ensured that the properties such as dimensional stability, impermeability, weight reduction and soundproofing of an electrical component carrier produced in this way are improved.

At the in 1 illustrated embodiment is an electrical component carrier with a fixed micro-switch 3 , The electrical component carrier has an electrically insulating base part 1 on, in the electrical conductor tracks 2 are arranged. The base part 1 thus forms the Vorumspritzling. The tracks 2 in the base part 1 are preferably pre-molded in the manner described above, to a first fixation in the base part 1 to enable. The microswitch 3 is in the base part 1 been fixed, with electrical contacts 4 of the microswitch protrude. The electrical contacts 4 are for electrical contact with the tracks 2 been soldered with these. The resulting solder joints 5 are like out 1 clearly exposed and thus exposed to damaging influences such as moisture and dust particles.

To the electrical contact points such as solder joints 5 to protect, the in 1 shown electrically encapsulated with a foamed insulating material, so that electrical contact points such as solder joints 5 to be protected. Preferably, the electrical conductor tracks 2 in the base part 1 completely enveloped to completely seal against external influences. If an area for external electrical contacting is provided on the electrical component carrier, then this area remains correspondingly free. In 1 For example, such an area is the end area 6 provided the electrical conductors, according to the Electric component carrier protrudes, for example, to form a plug connection to the outside.

How out 1 the microswitch is visible 3 in this case by means of snap connections on the side surfaces of the microswitch 3 in the base part 1 fixed, with other positive and / or non-positive connections are conceivable. It is also advantageous for such positive and / or non-positive connections between the base part 1 and electrical components such as microswitches 3 to renounce. The microswitch 3 can by electrical contacting, for example, a soldering to electrical conductors 2 and thus also on the base part 1 be fixed. When encapsulation with a foamed insulating material can then simultaneously a final fixation of the microswitch 3 carried in the electrical component carrier by the microswitch 3 is at least partially wrapped or encased with foamed insulating material. This eliminates the need for separate positive and / or non-positive connections for fixing a microswitch 3 at the base part 1 be provided so that an overall efficient production is possible.

LIST OF REFERENCE NUMBERS

1

base

2

electrical conductors

3

microswitch

4

electrical contacts of a microswitch

5

soldered point

6

End region of electrical conductors

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 1357774 A1 [0009]
• EP 1170110 A1 [0010, 0025]

Claims (10)

Method for producing an electrical component carrier, in particular for a motor vehicle, wherein the electronic component carrier has an electrically insulating base part ( 1 ) and arranged therein electrical conductor tracks ( 2 ), wherein at least one electrical component ( 3 ) for electrical contacting to the conductor track ( 2 ) is fixed, characterized in that the conductor tracks ( 2 ) are encapsulated with a foamed insulating material, preferably foamed plastic, in such a way that electrical contact points ( 5 ) are protected or isolated. Method according to the preceding claim, in which, during encapsulation with the foamed insulating material, the conductor tracks ( 2 ), except for any areas ( 6 ) of the conductor tracks for an external electrical contacting of the electrical component carrier. Method according to one of the two preceding claims, in which, in a first step, that in the base part ( 1 ) arranged electrical conductor tracks ( 2 ) are at least partially encapsulated in an injection molding process. Method according to the preceding claim, in which one or more support elements for electrical components are provided in the injection molding process. Method according to one of the preceding claims, wherein for the foamed insulating material, a foamed thermoplastic is used, which is foamed in particular with a physical or chemical blowing agent. Method according to one of the preceding claims, wherein the foamed insulating material, the electrical conductor tracks ( 2 ) completely enveloped and / or at least partially encapsulated the electrical components, preferably with a wall thickness of at least 1 mm. Method according to one of the preceding claims, wherein the electrical component as a micro device, in particular microswitch ( 3 ) and / or the dimensions of the electrical component are not more than 30 mm, preferably not more than 20 mm. Method according to one of the preceding claims, in which one or more electrical components ( 3 ) are fixed at protruding or recessed contact points in particular contact lugs of the conductors. Method according to one of the preceding claims, in which electrical components ( 3 ) are fixed by soldering, gluing, welding and / or cold pressing. Electric component carrier for a motor vehicle, preferably produced according to one of the preceding claims, having an electrically insulating base part ( 1 ) and arranged therein electrical conductor tracks ( 2 ), wherein the interconnects with at least one electrical component, in particular microswitches ( 3 ) are in electrical contact, characterized in that the electrical contact points are protected by an insulating sheathing with foam structure.

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