Shielding for electrical or electronic components with sensitive electromagnetic compatibility

Abstract

The invention relates to a shielding for electrical or electronic components with sensitive electromagnetic compatibility, to be specific cables and wires, wiring harnesses, wire and cable connectors, cable ducts, fuses, circuits, capacitances and / or inductances. The shielding consists of a multilayer-film arrangement comprising electrically conductive constituents or materials. The multilayer-film arrangement has at least three layers based on a synthetic rubber, each of the individual layers having at least partially different shielding attenuation or absorption attenuation in terms of the shielding-frequency range in such a way that shielding-attenuation losses occurring over the shielding-frequency range are reduced and the overall shielding attenuation is increased. Each of the individual layers contains magnetic, dielectric, electrically conductive and / or resistive filling materials.

Description

[0001] Shielding for electrical or electronic components sensitive to electromagnetic compatibility

[0002] Description

[0003] The invention relates to a shielding for electrical or electronic components sensitive with regard to their electromagnetic compatibility, namely cables and lines, cable harnesses, line and cable connectors, cable ducts, fuses, circuits, capacitors and / or inductors, consisting of a multilayer film layer arrangement with electrically conductive components or materials according to the preamble of claim 1.

[0004] Cable shields or electrical conductors with such cable shields are already known, for example, from DE 10 2020 108 058 Al.

[0005] These cable shields have first and second wire windings, each having a plurality of turns.

[0006] Turns of the plurality of turns of the first wire winding and corresponding turns of the plurality of turns of the second wire winding intersect at a first intersection point such that a plurality of first intersection points of the first wire winding and the second wire winding are present in the direction of the longitudinal axis. Several first intersection points extend at least approximately helically in the direction of the longitudinal axis of the conductor. EMC shielding devices are also known, e.g., according to DE 10 2014 104 290 A1, which are used in particular for shielding cable harnesses.

[0007] The shielding sheath provided there consists of a knitted, warp-knitted, woven, and / or braided fabric. The sheath is made of a combination of at least one tinned copper strand and at least one electrically conductive metal fiber.

[0008] Magnetic tapes for suppressing radiation noise are already known, for example, from DE 199 09 569 C2. A magnetic tape component therein comprises magnetic powder and rubber or a flexible resin. Furthermore, a metal foil is provided on one of the surfaces of the magnetic tape component.

[0009] The state of the art also includes electromagnetic shielding paints or shielding films, e.g., according to DE 199 11 304 A1. Such shielding paints or shielding films comprise ferrite powder, electrically conductive powder, and a binder. A manganese-zinc ferrite, a hexaferrite, and, in particular, a strontium ferrite are used as the ferrite. The conductive material is, for example, nickel or carbon black.

[0010] The generic DE 10 2011 077 187 B4 relates to a shield and a method for producing such a shield.

[0011] The shielding serves to protect electrical and / or electronic components and comprises a first semi-finished product made of a first film of electrically insulating material and a second semi-finished product made of a second film of likewise electrically insulating material.

[0012] The first and second films are connected to one another in such a way that they enclose at least one electrical and / or electronic component arranged between them.

[0013] The first and second films are provided, at least in some areas, with a layer of an electrically conductive material on the side facing the components. Furthermore, the first and / or second films have a so-called connecting region in which no layer of conductive material is present.

[0014] Such shielding should, in particular, be manufactured simply and as automatically as possible and should also be usable under difficult and changing conditions.

[0015] The electrically conductive material can be, for example, a conductive paste containing electrically conductive particles, but also a wire mesh, an electrically conductive foil or a thin metal sheet or a layer of electrically conductive particles.

[0016] The necessary shielding of electronic and electrical components to protect against electromagnetic interference (EMC) has long been a concern regarding operational safety and the susceptibility of electronic devices. Shielding is particularly important when transmitting high voltages and for components or devices subject to high frequencies.

[0017] As described, metal wire meshes are well known as shielding materials, as are the use of conductive foils or foils containing conductive components.

[0018] Based on tests conducted by the applicant with different magnetic ferrites and taking into account known shielding materials, it has been shown that shielding structures, in particular metal structures, lead to so-called shielding attenuation drops in the form of resonance drops over the respective shielding frequency range.

[0019] These frequency-dependent shielding attenuation drops lead to losses in the shielding of up to minus 40 dB when distributed across the frequency harmonics.

[0020] From the above, it is the object of the invention to provide a novel intelligent shielding with regard to its electromagnetic compatibility of cables and lines, line and cable connectors and cable ducts, wherein the shielding is capable of minimizing resonance dips in the shielding attenuation and increasing the overall shielding attenuation without resorting to known metallic shielding braids or knitted shielding fabrics.

[0021] The object of the invention is achieved by a shield according to the combination of features according to patent claim 1 and by a method for producing such a shield according to the teaching of patent claim 8.

[0022] It is therefore assumed that shielding is provided for electrical or electronic components that are sensitive to electromagnetic compatibility (EMC). Such components include cables and wires, cable harnesses, cable and cable connectors, cable ducts, fuses, circuits, capacitors, and / or inductors.

[0023] The shielding consists of a multilayer foil layer arrangement with electrically conductive components or materials.

[0024] According to the invention, the multilayer film arrangement comprises at least three layers based on a synthetic rubber.

[0025] Each of the individual layers has a shielding attenuation which is at least partially different with regard to the shielding frequency range in such a way that overall shielding attenuation drops occurring over the shielding frequency range are reduced and the overall shielding attenuation is increased.

[0026] In this regard, each of the individual layers has or contains magnetic, electrically conductive and / or resistive filling materials.

[0027] The individual foils comprise iron powder, manganese-zinc ferrite powder, strontium ferrite powder, graphite powder and / or carbon black as components.

[0028] Additionally, the individual layers can have a conductive coating. This coating can be applied by spraying, painting, or the like. In one embodiment of the invention, the filler materials can be formed as a film surrounded by at least one cover film layer made of synthetic rubber.

[0029] Each of the individual layers has a minimum thickness of essentially 0.4 mm.

[0030] The individual layers are preferably based on ethylene propylene diene rubber (EPDM).

[0031] Each of the individual layers therefore has a different frequency-dependent shielding and absorption behavior, so that the combination of the individual layers results in optimal shielding effect and resonance damping behavior of the shielding over a wide frequency range.

[0032] In the process for producing the shielding described above, the individual layers are first drawn from unvulcanized rubber mixtures.

[0033] The drawn individual layers are then softly folded together depending on the later application, so that a pre-doubled multi-layer structure is created.

[0034] Subsequently, the resulting multi-layer structure is subjected to pressure, temperature and time-controlled vulcanization.

[0035] In addition, several separately pre-doubled single layer combinations can be subjected to a later joint vulcanization step.

[0036] According to the teaching of the invention, a multilayer shielding polymer film system with a plurality of absorber films can be created, which is effective in a frequency range from 0.0001 GHz to over 100 GHz and is particularly used in cable shielding structures.

[0037] Resonance drops in shielding attenuation are minimized and the shielding attenuation is uniformed and increased over a wide frequency range.

[0038] The base polymer used is EPDM with at least one of the following filler materials: carbon black, iron, manganese zinc ferrite, and strontium ferrite. The filler material of the individual absorber layers can be magnetic, dielectric, or resistive particles, foils, meshes, flak, nanoparticles, or fibers. Depending on the desired shielding properties, the individual layers can be combined in different ways.

[0039] During production, the films are provided as individual unvulcanized films or sheets and are then stacked on top of each other and vulcanized together.

[0040] The AUMA process is used for the vulcanization step. Vulcanization parameters include 100 bar pressure and 170°C temperature at a throughput speed of 0.5 m per minute.

Claims

Claims 1.The invention relates to a shield for electrical or electronic components which are sensitive with regard to their electromagnetic compatibility, namely cables and lines, cable harnesses, line and cable connectors, cable ducts, fuses, circuits, capacitors and / or inductors, consisting of a multilayer film layer arrangement with electrically conductive components or further materials, characterized in that the multilayer film layer arrangement comprises several, preferably at least three layers based on a synthetic rubber, wherein each of the individual layers has an absorption or shielding attenuation which is at least partially different with regard to the shielding frequency range, such that shielding attenuation drops occurring over the shielding frequency range are reduced and the overall shielding attenuation is increased and each of the individual layers contains magnetic, dielectric, electrically conductive and / or resistive filler materials.

2. Shielding according to claim 1, characterized in that the individual foils contain iron powder, manganese-zinc ferrite powder, strontium ferrite powder, graphite powder and / or carbon black as components.

3. Shielding according to claim 1 or 2, characterized in that at least one individual layer or individual film has an additional conductive coating.

4. Shielding according to claim 1 or 3, characterized in that the filling materials themselves are designed as a film which is surrounded by at least one cover film layer made of synthetic rubber or the filling materials are incorporated into the synthetic rubber which is designed as a film.

5. Shielding according to one of the preceding claims, characterized in that each of the individual layers has a thickness of at least substantially 0.4 mm.

6. Shielding according to one of the preceding claims, characterized in that the individual layers are based on ethylene-propylene-diene rubber.

7. Shielding according to one of the preceding claims, characterized in that each of the individual layers has a different frequency-dependent absorption or shielding behavior.

8. A method for producing a shield according to at least one of the preceding claims, characterized by the following steps: - Drawing of individual layers from unvulcanized rubber compounds; - soft merging of the individual layers selected according to the application to form a pre-doubled multi-layer structure; - Pressure-temperature and time-controlled vulcanization of the resulting multi-layer structure.

9. Method according to claim 8, characterized in that several separately pre-doubled individual layers are subjected to a subsequent common vulcanization step.