Electrical contact device and method for producing an electrical contact device

Abstract

The invention relates to an electrical contact device (1), in particular for use in a motor vehicle (2), comprising a plurality of bus bars (3), which are at least partially surrounded by a first electrically insulating plastic (4), such that the handling and / or operation of the contact device (1) can be free from the risk of electric shock, a second electrically insulating plastic (5) is arranged at least partially between the bus bar (3) and the first plastic (4), which second plastic bears against the bus bar (3) on one side and against the first plastic (4) on the other side, the first plastic (4) having a greater hardness than the second plastic (5).

Description

TECHNICAL FIELD

[0001] The present invention relates to an electrical contact device, in particular for use within a motor vehicle, comprising a plurality of busbars, which are at least partially surrounded by a first electrically insulating plastic, such that handling and / or operation of the contact device can be performed without risk of electric shock. The present invention further relates to a method for manufacturing an electrical contact device. BACKGROUND

[0002] In electrically powered vehicles, the use of plastic-metal components, for example in electrical contact devices such as plugs for transmitting electrical signals or high electrical power, is widespread. These electrical contact devices often play a crucial role as connecting elements between sensitive control devices or power electronics units and areas in the motor vehicle that are exposed to moisture or oil. Therefore, in order to protect sensitive electronic components from harmful media, these components must be properly sealed.

[0003] Several techniques and methods have been developed to improve the sealing, in particular at the point of contact between plastic and metal in electrical contact devices. For example, the solution described in patent application DE 102012202004 A1 is based on a form-fit connection, in which the connection between the materials is improved mechanically.

[0004] Despite the various techniques and methods available, the sealing between plastic and metal components in such electrical contact devices remains a challenge. The main problem here is the different thermal expansion of plastic and metal. During the lifetime of the components or during lifetime tests in which the components are heated and cooled several cycles, a separation of the metal and the plastic can occur within the contact device. This separation leads to the formation of small cracks through which harmful media can penetrate. This problem is further exacerbated by the capillary effect, increasing the risk of media ingress and impairing the functionality and service life of the electrical contact device and / or electronic components in the motor vehicle.

[0005] The prior art does not always provide a reliable and lasting solution to this problem, as they are generally not able to effectively counteract the effects of repeated thermal cycles that can occur during the lifetime of the motor vehicle. SUMMARY

[0006] It is therefore an object of the present invention to provide an electrical contact device with a high and reliable sealing level against media ingress and which can be manufactured cost-effectively. Furthermore, it is an object of the present invention to realize a method for manufacturing an electrical contact device which is able to cost-effectively manufacture an electrical contact device with a high and reliable sealing level.

[0007] This object is achieved by an electrical contact arrangement, in particular for use within a motor vehicle, comprising a plurality of busbars, which are at least partially surrounded by a first electrically insulating plastic, such that handling and / or operation of the contact arrangement can be performed without risk of electric shock, wherein between the busbars and the first plastic at least partially a second electrically insulating plastic is arranged, which abuts on one side against the busbars and on the other side against the first plastic, and the first plastic has a greater hardness than the second plastic.

[0008] This provides the advantage that via the different plastics an improved connection technology is provided for the plastic-metal components within the electrical contact arrangement, which is able to maintain a high sealing level even under the conditions of repeated thermal cycles and different thermal expansions of the materials used. The electrical contact arrangement according to the invention is able to effectively prevent the formation of micro-gaps and the ingress or passage of harmful media through the electrical contact arrangement by using different plastics, in order to improve the reliability and service life of the electronic components and / or the contact arrangement.

[0009] The first plastic can preferably be designed as a housing for the electrical contact arrangement. The plastic housing can in particular be provided on the inside with a structured surface or microstructure, which can contribute to improved handling and also to an increased surface roughness, in particular to improved adhesion of the second plastic to such structures. In principle, it is conceivable to design the housing as one part or as multiple parts. Furthermore, the housing can preferably be equipped with integrated fastening elements or mechanisms, such as snaps, screws or bayonet closure devices, in order to enable simple, secure and tool-free mounting and removal of the contact arrangement on electrical components or housing parts above or below one another. The housing can also be divided into multiple compartments, which isolate the busbars, various electronic components and / or connections from one another, in order to prevent interference or short circuits between different parts of the contact arrangement.

[0010] The first plastic can preferably be selected from the group consisting of thermoplastic plastics, in particular polycarbonate (PC), polyethylene (PE), polypropylene (PP) and ABS (acrylonitrile-butadiene-styrene), or polyetherimide (PEI), in particular also for forming the electrically insulating plastic housing for the contact arrangement. It can also be preferred that the first plastic is a fiber-reinforced plastic, wherein preferably one or more fibers selected from the group consisting of glass fibers, carbon fibers and / or aramid fibers are used for reinforcement, in order to increase the structural integrity and mechanical strength of a housing formed from the first plastic, for example.

[0011] The second plastic can preferably be formed as a sealing element of the electrical contact device. The sealing plastic can preferably have elasticity and flexibility to adapt to different surface shapes and structures and thus to ensure an improved sealing. The second plastic in combination with its geometry can also achieve a self-sealing property to automatically repair slight damages or leaks during use, thereby prolonging the service life of the contact device. The sealing plastic can also contain special adhesion promoters or additives that improve the adhesion between the sealing element and the metal or plastic parts of the contact device to further reduce the likelihood of leaks or sealing failure.

[0012] The contact device can also preferably be designed modularly to make it easily adaptable to different application scenarios. This modularity will allow multi-functional applications and ensure compatibility with a large number of electrical systems and components.

[0013] The second plastic and the first plastic can also be designed as a common component, such that for example the first plastic forms an electrically insulating housing for the contact device, while the second plastic serves as a sealing element arranged on this housing. The contact device can be equipped with one or more integrated sealing elements that prevent the ingress of moisture, dust and other contaminants. This in particular allows a simplified installation of the contact device, for example by inserting the busbar into the housing formed by the first plastic and subsequently closing the housing, whereby the sealing element formed by the second plastic is wrapped around the busbar and thus seals the busbar against the surroundings. Preferably, this embodiment can make use of a two-component injection molding technology, wherein the second plastic is applied directly to the housing as a sealing element during the manufacturing process, thereby achieving an integrated, seamless sealing, which further increases the reliability of the electrical connection.

[0014] It is also conceivable that the busbar and the second plastic form a common component and are then for example inserted into a housing formed by the first plastic, which can also contribute to a simplified installation of the electrical contact device. Preferably, this embodiment can also make use of a two-component injection molding technology, wherein the second plastic is applied directly to the busbar as a sealing element during the manufacturing process, thereby achieving an integrated, seamless sealing, which further increases the reliability of the electrical connection.

[0015] It is also possible that the first plastic forms a housing of the contact device, while the second plastic is realized as a separately formed sealing element. This makes it possible that the busbar, the housing made of the first plastic and the sealing element made of the second plastic are available as separate components, which are then assembled to form the contact device. This can have the advantage that different versions of the contact device can be manufactured particularly inexpensively and flexibly due to the modular design.

[0016] For the purposes of the present application, busbars, also referred to as power rails or electrical rails, are stationary electrical conductors for transmitting electric current between different components of an electrical system. Busbars can be made of different materials such as copper, aluminum or other electrically conductive alloys, which can be selected for their ability to conduct high currents as well as their heat resistance and mechanical stability. Depending on the specific requirements of the field of application of the electrical contact arrangement, busbars can be manufactured in various shapes and dimensions, for example, flat strips, solid blocks or tubular structures.

[0017] According to the present application, the first plastic has a greater hardness than the second plastic. The hardness of a plastic can be determined using various standardized methods. These methods are generally designed to measure the resistance of a plastic material to entering or deforming. In this context, a commonly used method is the Shore hardness test according to ISO 868 or ASTM D2240. Shore D and Shore A are the most commonly used scales for determining the hardness of plastics. Shore D is used for harder plastics, while Shore A is used for softer plastics.

[0018] In principle, the electrical contact arrangement can be provided for the transmission of electrical energy and / or for the transmission of data. The electrical energy can be transmitted in the high-voltage (HV) or low-voltage (NV) range.

[0019] Further advantageous embodiments of the present application are specified in the dependent claims. The features individually listed in the dependent claims can be combined with one another in a technically meaningful manner and can define further embodiments of the present application. In addition, the features indicated in the claims are specified and explained in more detail in the description, in which further preferred embodiments of the present application are shown.

[0020] According to an advantageous embodiment of the present application, the second plastic is a thermoplastic elastomer. The use of a thermoplastic elastomer (TPE) as a second plastic material offers various technical advantages. TPEs can be processed, for example, using common thermoplastic processing techniques such as injection molding, extrusion and thermoforming, thereby producing cost benefits and manufacturing flexibility. In addition, TPEs combine the elastic properties of rubbers and the processing advantages of thermoplastic plastics, enabling them to stretch under load and then return to their original shape. For example, the TPE can be selected from the group of styrene-based TPEs (SEBS, SBS), polyolefin-based TPEs (TPO, TPV), polyurethane-based TPEs (TPU), polyester-based TPEs (COPE, TPC) and polyamide-based TPEs (PEBA).

[0021] In this context, it is further preferred that the first plastic is not a thermoplastic elastomer.

[0022] According to a further preferred further development of the application, the second plastic is completely covered by the first plastic. This makes it possible to provide particularly good mechanical protection of the softer second plastic by the harder first plastic. Furthermore, it is possible to introduce a prestress of the second plastic into the second plastic in a particularly uniform distribution by means of the complete covering of the first plastic, which prestress of the second plastic is desirable for optimizing the sealing performance.

[0023] Furthermore, according to an equally advantageous embodiment of the application, the second plastic completely surrounds the busbar along the cross-sectional circumference of each busbar, which contributes to further improving the sealing performance.

[0024] According to a further particularly preferred embodiment of the application, the contact device is designed as a plug or a connection ring.

[0025] The plug is used to establish a temporary but secure electrical connection without the need for permanent fastening, for example by soldering. This makes it possible for the electrical components to be easily connected and disconnected, thus simplifying installation, maintenance and repair. For example, the plug can be designed as a connector, in which the plug is inserted directly into a corresponding socket. The plug can also be configured, for example, as a screw connector, which is then screwed into a corresponding socket. Another possibility is to design the plug as a bayonet connector.

[0026] The object of the application is also achieved by a method for producing an electrical contact device, in particular for use in a motor vehicle, comprising the following steps: - providing a plurality of busbars; - providing a first electrically insulating plastic; - providing a second electrically insulating plastic, wherein the first plastic has a greater hardness than the second plastic; - arranging the second plastic at least partially between the busbars; - arranging the first plastic at least partially on the second plastic, such that the second plastic rests against the busbars on one side and against the first plastic on the other side, and / or such that handling and / or operation of the contact device is possible without the risk of electric shock.

[0027] It is basically possible for the housing to be formed first from the first plastic, and then for the second plastic and the busbars to be accommodated in the housing.

[0028] It is also possible for a separate sealing element to be formed from the second plastic and then to be installed between the busbars and the first plastic.

[0029] In a likewise preferred embodiment of the application, the busbar can be overmoulded with the second plastic. Preferably, the busbar is overmoulded with the second plastic in an injection moulding process. This eliminates the need for a separate installation of a second plastic piece on the busbar. Furthermore, the injection moulding process enables an accurate and consistent application of the second plastic, resulting in a uniform insulation and improved protection of the busbar. This increases the electrical safety by minimizing the risk of short circuits or electric shocks.

[0030] It can also be advantageous to further improve the application such that the busbar and / or the second plastic is overmoulded with the first plastic, which contributes to an improved sealing and mechanical stability of the electrical contact arrangement.

[0031] According to a further preferred embodiment of the application, the first plastic and the second plastic used for forming the electrical contact arrangement are injected in a two-shot injection moulding process, such that the entire electrical contact arrangement can be manufactured in one injection moulding process. The use of a two-shot injection moulding process for manufacturing the entire electrical contact arrangement in a single process step provides several technical advantages. A significant advantage lies in the process efficiency. Since the entire contact arrangement is manufactured at once, the cycle time is significantly reduced. This contributes to a reduction of the manufacturing costs. Furthermore, potential problems and uncertainties that can arise from handling between different processing steps are also minimized.

[0032] By using a two-shot injection moulding process, it is also possible to improve the structural integrity and quality of the end product. The simultaneous injection of different plastic materials enables a good bond between the materials, resulting in a more uniform and durable component. This improved bond minimizes the risk of defects, weaknesses or delamination in the end product, thereby increasing the reliability and lifetime of the contact arrangement.

[0033] Finally, the application can also be advantageously implemented such that the first plastic is applied to the second plastic, such that the first plastic induces a pre-stress of the second plastic relative to the busbar. For example, by simultaneously or subsequently overmoulding the second plastic with the first plastic, an additional pressure can be built up on the first plastic, thereby creating a kind of pre-stress between the second plastic and the busbar. This pre-stress prevents the busbar and the second plastic from separating from each other due to their different thermal expansions, which can occur for example during the operation of a motor vehicle due to thermal loads, which further improves the sealing of the electrical contact arrangement, in particular in a thermally fluctuating operating environment. BRIEF DESCRIPTION OF DRAWINGS

[0034] The application is explained in more detail below with reference to the drawings, without limiting the general idea of the application.

[0035] In the drawings: Figure 1 Different manufacturing states of the electrical contact arrangement are shown, each in a perspective view; Figure 2 The busbar is shown in a schematic cross-sectional view; Figure 3 A motor vehicle with an electrical contact device is shown in a schematic block diagram. DETAILED DESCRIPTION

[0036] Figure 1 The illustrations a to c of Fig. 1 show an electrical contact device 1, in particular for use within a motor vehicle 2, as is also shown by way of example in Figure 3 In the illustrated embodiment, the contact device 1 is designed as a plug 7.

[0037] The electrical contact device 1 comprises a plurality of busbars 3, which are surrounded by a first electrically insulating plastic 4, so that handling and / or operating the contact device 1 can be done without risk of electric shock, for example, as is shown in Figure 1 illustration c of Fig. 1. The first plastic 4 thus forms a housing for the electrical contact device 1.

[0038] In the illustrated exemplary embodiment, there are a total of four busbars 3, which have a rectangular conductor cross section and extend substantially parallel to one another. Arranged between the busbars 3 and the first plastic 4 is a second electrically insulating plastic 5, which rests against the busbars 3 on one side and against the first plastic 4 on the other side, wherein the first plastic 4 has a greater hardness than the second plastic 5. In the illustrated embodiment, the second plastic 5 is a thermoplastic elastomer. The second plastic 5 thus forms a sealing element that seals the busbars 3 relative to the first plastic 4. Figure 1

[0039] Some of the busbars 3 have a fixing / connection section 8 that protrudes from the busbar 3 and enables improved fastening of the second plastic 5 to the busbar 3, in particular an optimized fixing against displacement in the longitudinal direction of the busbar 3. The fixing / connection section 8 thus protrudes substantially perpendicularly to the longitudinal direction of the busbar 3 from the busbar. The fixing / connection section 8 can then rest against the second plastic 5 and / or extend through the second plastic.

[0040] As can be clearly seen from Figure 1 illustration c, the second plastic 5 is completely covered by the first plastic 4. The second plastic 5 completely surrounds the busbar along the cross-sectional circumference 6 of each busbar 3, as can be clearly seen in Figure 2

[0041] A possible method for manufacturing the electrical contact device 1 is explained in more detail below. Basically, this involves the following steps: First, a plurality of busbars 3, a first electrically insulating plastic 4 and a second electrically insulating plastic 5 are provided, wherein the first plastic 4 has a greater hardness than the second plastic 5.​​

[0042] Subsequently, the second plastic 5 is arranged at least partially between the busbars 3, as can also be seen in Figure 1 Fig. b. Thereafter, the first plastic 4 is arranged at least partially on the second plastic 5, such that the second plastic 5 abuts against the busbars 3 on one side and against the first plastic 4 on the other side, and such that handling and / or operation of the contact device 1 is possible without risk of electric shock. This manufacturing state is shown in Figure 1 Fig. c.

[0043] In the exemplary embodiment shown in Figure 1 Fig. b, the busbars 3 are overmoulded with the second plastic 5. As can be seen in Figure 3 Fig. c, the second plastic 5 is also completely overmoulded with the first plastic 4. The first plastic 4 and the second plastic 5 can be injected in a two-shot injection-moulding process to form the electrical contact device 1.

[0044] The first plastic 4 is applied to the second plastic 5 such that the first plastic 4 induces a prestress of the second plastic 5 relative to the busbars 3.

[0045] It is also possible to first perform an injection-moulding of the second plastic 5, which is designed as a thermoplastic elastomer, all around the busbars 3 in a first injection-moulding process. This injection-moulded second plastic 5 can perform additional functions in addition to sealing and insulation, for example positioning the busbars 3 relative to one another. In a second injection-moulding process, the complete geometry of the second plastic 5 is then overmoulded with the rigid first plastic.

[0046] Figure 3 A possible application of the contact device 1 in a motor vehicle 2 is shown. In this case, a first contact device 1 designed as a plug 7 is used to electrically contact a controller 10 with an electric motor 9, and a second contact device 1 designed as a plug 7 is used to electrically contact an electric energy source 11 with the electric motor 9.

[0047] The invention is not limited to the embodiments shown in the drawings. Thus, the above description is not to be regarded as limiting, but rather as illustrative. The appended claims are to be interpreted in the sense that the stated features are present in at least one embodiment of the invention. This does not exclude the presence of further features. In the case of claims and the above description defining a “first” feature and a “second” feature, this nomenclature is used to distinguish between two features of the same type, without defining a priority order.

[0048] List of reference signs 1 contact device 2 motor vehicle 3 busbar 4 first plastic 5 second plastic 6 cross-sectional circumference 7 plug 8 fixing / connection section 9 electric motor 10 controller 11 energy

Claims

1. An electrical contact device (1), particularly for use in a motor vehicle (2), the electrical contact device comprising a plurality of busbars (3) at least partially surrounded by a first electrically insulating plastic (4), such that handling and / or operation of the contact device (1) is free from the risk of electric shock. Its features are, A second electrically insulating plastic (5) is arranged at least partially between the busbar (3) and the first plastic (4), the second electrically insulating plastic abutting against the busbar (3) on one side and against the first plastic (4) on the other side, the first plastic (4) having a greater hardness than the second plastic (5).

2. The contact device (1) according to claim 1. Its features are, The second plastic (5) is a thermoplastic elastomer.

3. The contact device (1) according to claim 1 or 2. Its features are, The second plastic (5) is completely covered by the first plastic (4).

4. The contact device (1) according to any one of the preceding claims. Its features are, The second plastic (5) completely surrounds the busbar along the cross-sectional perimeter (6) of each busbar (3).

5. The contact device (1) according to any one of the preceding claims. Its features are, The contact device (1) is designed as a plug (7) or a connecting ring.

6. A method for manufacturing an electrical contact device (1), particularly for use in a motor vehicle (2), the method comprising the steps of: - Provides multiple busbars (3); - Provide the first electrically insulating plastic (4); - Provide a second electrically insulating plastic (5), wherein the first plastic (4) has a greater hardness than the second plastic (5); - The second plastic (5) is arranged at least partially between the busbars (3); - The first plastic (4) is arranged at least partially on the second plastic (5) such that the second plastic (5) abuts against the busbar (3) on one side and against the first plastic (4) on the other side, and the handling and / or operation of the contact device (1) is made risk-free from electric shock.

7. The method according to claim 6, Its features are, The busbar (3) is molded by covering it with the second plastic (5).

8. The method according to claim 6 or 7, Its features are, The busbar (3) and / or the second plastic (5) are molded by covering the first plastic (4).

9. The method according to any one of claims 6 to 8, Its features are, The first plastic (4) and the second plastic (5) are injected using a double injection molding process to form the electrical contact device (1).

10. The method according to any one of claims 6 to 9, Its features are, The first plastic (4) is applied to the second plastic (5) such that the first plastic (4) causes the second plastic (5) to have a prestress relative to the busbar (3).

Images