Method for producing an electrical component and electrical component

Abstract

Method for producing a component extending in a longitudinal direction (L), in particular an electrical component, with a protective sheath (10) made of a sheath material selected from silicone or an elastomer, wherein the component is placed into a casting mold (4) together with a protective sheath (12) surrounding the component, and the sheath material is then introduced into an intermediate region (14) between the component and the protective sheath (12) and into an outer region (18) between the protective sheath (12) and a wall of the casting mold (4), so that the protective sheath (12) is embedded in the sheath material over its entire length, wherein - the jacket material is introduced into the casting mould (4) at a frontal pouring side (6) of the casting mould (4) and thus in the longitudinal direction (L) and the jacket material is deflected at a tool side (8) of the casting mould (4) opposite the pouring side (6) and transferred into the outer area (18) and / or - the protective sheath (12) has at least one hole or a plurality of holes through which the sheath material passes radially.

Description

[0001] The invention relates to a method for producing an electrical component extending in a longitudinal direction with a protective sheath made of a sheath material selected from silicone or an elastomer, and to such a component.

[0002] For electrical components, especially cables, and especially prefabricated cable assemblies, a silicone sheath is often used as an outer protective coating. Cables with silicone sheaths are frequently used in areas subject to high thermal stress for heat protection or as mechanical protection.

[0003] DE 10 2021 205 057 A1 describes a process in which, to form a grommet, a cable harness is inserted into a mold together with an insert as a reinforcement element. Liquid silicone is introduced laterally into the mold to form a silicone jacket. This is irradiated with UV light from the outside via a transparent wall area of ​​the mold to cure it.

[0004] DE 37 41 943 A1 describes a process in which a bundle of individual cables is first surrounded by a banding before being cast around.

[0005] DE 20 2013 102 542 U1 describes a protective sheath for a cable, particularly for use in the automotive sector. It has a two-layer construction with an inner layer, e.g., a fabric layer, and an outer layer made of silicone. The protective sheath serves as mechanical protection, particularly impact protection.

[0006] DE 10 2006 056 645 A1 also discloses a multi-layer protective sheath for a cable, in which a braided sleeve, which may be impregnated with silicone, serves as the inner layer. A second layer, which may be a silicone layer filled with finely distributed particles, is applied to this. This layer structure can be repeated or surrounded by a third outer layer, which, for example, has a similar structure to the first layer.

[0007] However, cables sheathed with silicone or elastomer have the problem that they are not sufficiently notch-resistant or tear-resistant, i.e. as soon as a notch or tear appears on the surface of the sheath, it spreads quickly and easily to the cable core.

[0008] US 2015 / 0 228 381 A1 discloses a cable harness with a heat shield in which an embedded support ring prevents sheath material from escaping outside the heat shield during a casting process.

[0009] DE 10 2018 220 197 B3 and WO 2001 / 042 055 A1 each describe cable bundles surrounded by a protective sheath, in which the individual cable elements are surrounded by annular spacer elements that are embedded in the protective sheath.

[0010] WO 2016 / 027 629 A1 describes an electromagnetic shielding element which is formed by immersing a metallic shielding body in a plastic bath, followed by curing and bending.

[0011] EP 2 957 408 A1 describes a method for overmolding a sensor attached to a cable end.

[0012] Proceeding from this, the object of the invention is to provide a method for producing an electrical component, in particular a cable, as well as such a component, which has a protective sheath made of a sheath material selected from silicone or an elastomer, which has a high notch strength.

[0013] The object is achieved according to the invention by a method for producing an electrical component extending in a longitudinal direction with a protective sheath made of a sheath material selected from silicone or an elastomer, in which the component is placed into a casting mold together with a protective sheath surrounding the component and then sheath material is introduced into an intermediate region between the component and the protective sheath and into an outer region between the protective sheath and a wall of the casting process.

[0014] The object is further achieved according to the invention by an electrical component which is produced in particular according to the method described above and which is surrounded by a protective sheath made of a sheath material selected from silicone or an elastomer with an interposition of a protective sheath, wherein the protective sheath is formed in an intermediate region between the component and the protective sheath and in an outer region outside the protective sheath. In the intermediate region, therefore, an intermediate sheath and in the outer region an outer sheath made of the same sheath material are formed. The outer sheath in particular forms only a thin outer skin. Due to the special manufacturing process, the intermediate sheath and the outer sheath together form a monolithic sheath in which the protective sheath is embedded.

[0015] The protective sheath provides mechanical protection, specifically notch protection. The special manufacturing process ensures that this protective sheath is positioned in an outer region and, in particular, embedded in the otherwise homogeneous sheath material of the protective sheath. In the event of mechanical damage, such as a crack or notch, the protective sheath prevents the crack or notch from propagating radially into the interior. The protective sheath therefore ensures the integrity of the intermediate sheath, even in the event of mechanical damage to the outer skin.

[0016] When we speak here of the protective sheath surrounding the component, we understand that the protective sheath completely encloses the component's circumference, viewed in the longitudinal direction, like a hose or tube. Specifically, the protective sheath is cylindrical in shape. Alternatively, it can be tube- or hose-like and curved, for example, even with multiple bends.

[0017] The protective sheath is preferably made of a plastic and / or a mechanically resistant material. For example, the protective sheath is made of or comprises durable aramid fibers, glass fibers, etc. A plastic is, in particular, a plastic different from the silicone protective sheath, in particular a non-silicone plastic.

[0018] Silicone is used in particular as the sheath material. Conventional silicone materials, such as those known from the prior art for the formation of silicone insulation sheaths, are used for the silicone. For example, liquid silicone, as described in DE 10 2021 205 057 A1, is used. Alternatively, silicone resin and / or silicone rubber are used. The silicone content in the material of the protective sheath is typically above 80 wt.%. Preferably, the protective sheath consists entirely of silicone or almost entirely of silicone (> 95 wt.%). After encapsulation, the silicone cures, preferably as part of a crosslinking process. For this purpose, UV-assisted crosslinking is provided, for example.

[0019] Instead of silicone, an elastomer, such as a thermoplastic elastomer (TPE) or a thermoplastic polyurethane (TPU), is generally used as the sheath material. Depending on the application, other suitable elastomers are also used. Silicone elastomers can also be used. Elastomers are generally relatively soft materials that often have only low notch or tear resistance. The elastomers preferably have a Shore A hardness (particularly according to DIN ISO 7619-1) in the range of 30 to 90, and especially in the range of 50 to 85.

[0020] Even when using an elastomer as the sheath material, the elastomer content in the protective sheath material is typically above 80 wt.%. Preferably, the protective sheath consists entirely or almost entirely (> 95 wt.%) of the elastomer or an elastomer mixture.

[0021] The sheath material, in particular the silicone material being encapsulated, preferably contains no additional fillers, such as filler particles or fibers. Preferably, no reinforcing elements are incorporated.

[0022] In a preferred embodiment, for example, one or more inserts are integrated specifically as functional elements, which protrude from the protective casing, for example, and serve to secure the component, and are designed, in particular, as fastening tabs. Such inserts are made, in particular, of metal. Even in such a variant with inserts, the casing material—apart from the insert—preferably does not contain any fillers or fibers for reinforcement.

[0023] The component is at least one, in particular, electrical cable, which is surrounded by a cable sheath as the outer sheath. The electrical cable is, in particular, a single-core cable with a central conductor, for example, a solid conductor or stranded conductor, which is surrounded by an insulating sheath as the cable sheath. Alternatively, it can also be a multi-core cable with several individual conductors surrounded by the cable sheath as the outer sheath.

[0024] Further preferably, the component is a cable bundle comprising a plurality of individual electrical lines, in particular single-core lines, wherein each line is surrounded by a cable sheath.

[0025] Specifically, the component is a prefabricated cable set in which connection elements such as plugs are preferably already preconfigured at the end.

[0026] In general, the cables or cable bundles are predefined components with a defined, predetermined length that are inserted into the mold either partially or completely. The protective silicone sheath preferably extends over the entire length of the component, except for the connection areas exposed at the ends. In some cases, such protective sheaths are only applied to cable harnesses in certain areas over a limited length, over which the protective silicone sheath then extends. In these cases, the protective silicone sheath extends, for example, over at least 50% of the length of the component. In general, the protective sheath preferably extends over at least 30 cm or at least 50 cm or even more. In principle, the concept described here can also be applied to components with shorter lengths. The concept is also suitable for small components with a length of, for example, a few centimeters.

[0027] However, the specific method described here is not limited to (electrical) wires or cables. The method can, in principle, also be applied to more complex, particularly electronic or electrical, component assemblies, such as grommets for sealing a penetration, electrical connectors, power distributors, rigid cable harnesses, busbars, supply lines in the form of a so-called backbone, and electronic assemblies such as circuit boards, sensors, actuators, etc. Preferably, the component is generally an elongated, strand-shaped component.

[0028] According to one inventive aspect, the jacket material is preferably introduced into the casting mold exclusively from a frontal sprue side of the casting mold, and thus in the longitudinal direction. During casting, the jacket material therefore flows longitudinally along the component, filling the casting mold. Unlike conventional lateral gates, this ensures that the jacket material is placed between the component and the protective sleeve, thus positioning the protective sleeve as far outward as possible and not pressed toward the component.

[0029] In a useful further development, the jacket material is introduced into the intermediate region only, or at least largely (>75%), in the longitudinal direction. This means that the jacket material is introduced into the casting mold via a sprue opening in a radial region in which the intermediate space is formed, so that the jacket material reaches the intermediate region completely or at least largely. The sprue opening is arranged, in particular, on the end face and within the described radial region, so that the casting material reaches the intermediate space.

[0030] From there, the shell material fills not only the intermediate space but also the outer space. This ensures that the protective shell is essentially pressed radially outward through the shell material, so that at the end of the casting process, the protective shell is positioned as far out as possible. The protective shell is thus essentially pressed toward a wall of the casting mold.

[0031] The shell material is deflected on a tool side of the casting process, longitudinally opposite the inlet side, and transferred to the outer space. In this way, the shell material also fills the outer space. Therefore, the shell material initially flows longitudinally from the inlet side in the gap to the opposite tool side, is deflected there, and then flows back toward the inlet side in the opposite longitudinal direction and opposite to the flow direction in the gap, filling the outer space.

[0032] In the finished state, this can be seen from the fact that at least on one end face of the protective sheath the sheath material covers one end face of the protective sheath.

[0033] Alternatively, or in addition, the sheath material passes through the protective cover into the outer area. This occurs particularly when the protective cover is suitably designed, i.e., when it has at least one or more openings through which the sheath material can pass.

[0034] According to one embodiment, the outer region is filled exclusively by the jacket material passing through the protective cover in a radial direction from the intermediate region into the outer region.

[0035] Alternatively, the protective cover is tight and no sheath material passes through.

[0036] In the finished state, this can be seen from the fact that the protective cover is penetrated by the jacket material and is thus virtually embedded in the jacket material.

[0037] According to a further inventive embodiment, the protective sheath accordingly has at least one and preferably a plurality of holes through which the sheath material can pass radially.

[0038] The protective sheath is preferably designed as a woven fabric. In this case, a woven fabric is generally understood to mean a structure consisting of a large number of individual strands or fibers. The woven fabric can in particular also be a braid. Preferably, free spaces are formed between these individual strands, which form the previously defined holes through which the sheath material can pass. The individual strands are spaced from one another in particular by a mesh size, which is, for example, in the range between 0.5 and 5 mm. At least the mesh size is preferably large enough for the sheath material to penetrate through the individual meshes. A large mesh size is also advantageous for the frequently required UV crosslinking. The braid is preferably made of plastic, alternatively also of metal. In this case, the braid also achieves a shielding effect.

[0039] Alternatively, the protective sheath is designed to be closed and impermeable to the sheath material. The protective sheath is designed, for example, in the form of a foil. This can be a plastic foil, preferably a metallic foil. It is also possible for the protective sheath to be designed in the form of an inherently rigid tube.

[0040] As already explained at the beginning, the protective sheath is preferably generally tubular or pipe-shaped, and preferably hollow-cylindrical. The protective sheath therefore has openings at its front ends. These allow the sheath material to enter and, if necessary, exit during the casting process.

[0041] According to one design variant, the protective sheath is flexible and not inherently rigid. Therefore, in the variant where the sheath material is inserted into the intermediate area, the protective sheath is automatically pushed outward during the casting process by the sheath material.

[0042] Alternatively, the protective cover is preferably inherently rigid, meaning it is self-supporting, so that it maintains its predetermined shape, for example, cylindrical, without any additional support functions. This prevents the protective cover from collapsing toward the component or being compressed during the casting process. This inherently rigid variant specifically ensures that the protective cover is positioned at a defined distance from the component.

[0043] According to a preferred embodiment, the protective sheath—for example, in the flexible but also in the inherently rigid embodiment—has spacers oriented radially inward toward the component, so that the protective sheath is spaced apart from the component via the spacers. The spacers are, in particular, integral, particularly monolithic components of the protective sheath.

[0044] Alternatively or additionally, the protective cover has radial spacers on its outer side, so that the protective cover is also held at a predefined distance from the wall of the mold. Preferably, however, spacers are arranged only on the inner side.

[0045] In the finished component surrounded by the protective sheath, the intermediate sheath preferably has a greater wall thickness than the outer sheath. In particular, the wall thickness is several times greater, for example twice, three times or four times greater, than the wall thickness of the outer sheath. In particular, the outer sheath is formed only by a thin outer skin. This preferably has a maximum wall thickness of 3 mm and in particular of only 1 mm. The wall thickness of the outer sheath is, for example, in a range between 1 mm and 3 mm. The wall thickness of the intermediate sheath, in contrast, is at least 2 mm or at least 4 mm and in particular at least 6 mm. For example, the wall thickness of the intermediate sheath is in a range between 2 mm and 7 mm. The total wall thickness of the intermediate sheath including the outer sheath is, for example, in the range between 3 mm and 10 mm.

[0046] Preferably, the protective sheath is completely covered by the outer sheath, meaning the protective sheath does not protrude radially from the outer sheath at any point. Alternatively, it is also possible for the protective sheath to protrude from the outer sheath at individual, discrete locations, meaning the protective sheath is exposed at these discrete locations and is not covered by the sheath material.

[0047] An embodiment of the invention is explained in more detail below with reference to the figures, which show, in schematic, highly simplified representations: Fig. 1 a perspective view of a casting mold with an electrical cable inserted therein to explain the casting process and Fig. 2 a cross-sectional view of a cable with a protective sheath surrounding it.

[0048] According to Fig. 1, to produce a component embodied in the exemplary embodiment as an electrical line 2, the component is placed into a mold 4, shown here only in a highly simplified manner. The line 2 and thus also the mold 4 extend in a longitudinal direction L. The mold 4 extends between two longitudinally opposite end faces, namely from a pouring side 6 to an opposite tool side 8.

[0049] The casting mold 4 is, in particular, a divisible tool mold, which in particular consists of two shell halves. Alternatively, the casting mold 4 is tubular with closable end faces. In the exemplary embodiment, the line 2 passes through the casting mold 4 and protrudes at the end. During the casting process, a protective sheath 10 is therefore only formed in a partial region of the line 2. Preferably, only the end regions of the line 2 designed as connection regions are without a protective sheath 10.

[0050] Before the casting process begins, a protective sheath 12, which is in particular a tubular mesh, is inserted into the casting mold 4. In the exemplary embodiment, this additionally comprises spacers 13. These are preferably designed as radially inwardly projecting struts, with three struts being shown in the exemplary embodiment. These are formed, for example, only at individual, discrete length positions or extend continuously over the entire length of the protective sheath 12.

[0051] Generally, the protective sheath 12 surrounds the line 2 in a tubular or tubular manner, and in particular concentrically. This creates an intermediate region 14 between the protective sheath 12 and the line 2. At the same time, the protective sheath 12 is spaced a certain distance from an outer wall 16 of the mold 4, so that an outer region 18 is formed between the protective sheath 12 and the mold 4 or the wall 16.

[0052] In the version according to Fig. 1, liquid silicone is introduced as casting material and jacket material exclusively at the frontal sprue side 6, specifically only into the intermediate region 14. During the casting process, the liquid silicone therefore flows in the flow direction S, indicated by the arrows, initially in the longitudinal direction L and successively fills the intermediate region 14. On the opposite tool side 8, the silicone is deflected radially outward and then flows back against the longitudinal direction L toward the sprue side 6, thus filling the outer region 18.

[0053] Therefore, a pouring opening (not shown in detail here) is preferably formed on the pouring side 6 in a radially inner region, through which the silicone is introduced. This pouring opening is located in a radial region which, when the protective cover 12 is inserted, is covered by the intermediate region 14.

[0054] Preferably, in a radially outer region, in particular in a radial region outside the intermediate region 14, an outlet opening is also formed on the sprue side 6, so that excess silicone can escape and / or venting can take place if necessary.

[0055] Alternatively or in addition to the deflection, the silicone passes through the protective cover 12 in a radial direction and thus fills the outer area 18.

[0056] In the Fig. 2 this is shown by a dashed representation of the protective cover 14, ie the protective cover 14 has a plurality of openings through which the silicone passes during the casting process and which are filled with silicone in the final state.

[0057] It is important to note that for both variants, the material is introduced into the intermediate region 14, so that the introduced silicone fills the protective sheath 12 and pushes it radially outward toward the wall 16. This ensures that the protective sheath 12 is positioned as far outward as possible.

[0058] The silicone forms the protective sheath 10 surrounding the cable 2, in which the protective sheath 12 is embedded. The silicone introduced into the intermediate region 14 forms an intermediate sheath 20, and the silicone introduced into the outer region 18 forms an outer sheath 22. The intermediate sheath 20 and outer sheath 22 together form a monolithic cast sheath made of the silicone material, in which the protective sheath 12 is embedded.

[0059] Preferably, at least one end face of the protective cover 12 is covered by the silicone. In particular, the end face on the tool side 8. According to Fig. 2, the opposite end face of the protective sheath 12 is also covered by silicone. Therefore, at least one end face and preferably both opposite ends of the protective sheath 10 are provided with a continuous annular silicone layer of the protective sheath 10, each covering the end face of the protective sheath 12. This annular silicone layer therefore connects the intermediate sheath 20 to the outer sheath 22 at the respective end face.

[0060] In general, a preferred embodiment provides for the protective sheath 12 to be arranged as far outward as possible. This means that the radial width of the intermediate region 14 and thus the wall thickness R1 of the intermediate sheath 20 is greater than the radial width of the outer region 18 and thus than the wall thickness R2 of the outer sheath 22. In particular, the wall thickness R1 of the intermediate sheath 20 is many times, in particular at least twice, or at least three times, or even four times greater than the wall thickness R2 of the outer sheath 22. The outer sheath 22 is preferably formed only by a thin outer skin.

[0061] Overall, this creates a particularly electrical component with a protective sheath 10 made of silicone, wherein the protective sheath 10, through the integration of the protective sheath 12, offers a high level of mechanical protection, particularly in the case of mechanical stress caused by cracking or notching. When exposed to an external notch force F and possible cracking, this force propagates through the thin outer skin to the protective sheath 12, as is the case with lightning in the Fig. 1. The electrical component is specifically the described electrical cable 2, or in particular a cable bundle comprising several individual cables and in particular a prefabricated cable set to which at least some components, in particular connectors, are already connected to the individual cables at the end. List of reference symbols 2 lines 4 Casting mold 6 Pouring side 8 Tool page 10 Protective sheath 12 protective cover 13 spacers 14 Intermediate area 16 wall 18 Outdoor area 20 intermediate jacket 22 Outer jacket L longitudinal direction S Flow direction R1 Wall thickness of the intermediate area R2 Wall thickness of the outdoor area F notch force

Claims

[1] Method for producing a component extending in a longitudinal direction (L), in particular an electrical component, with a protective sheath (10) made of a sheath material selected from silicone or an elastomer, wherein the component is placed into a casting mold (4) together with a protective sheath (12) surrounding the component, and the sheath material is then introduced into an intermediate region (14) between the component and the protective sheath (12) and into an outer region (18) between the protective sheath (12) and a wall of the casting mold (4), so that the protective sheath (12) is embedded in the sheath material over its entire length, wherein - the jacket material is introduced into the casting mould (4) at a frontal pouring side (6) of the casting mould (4) and thus in the longitudinal direction (L) and the jacket material is deflected at a tool side (8) of the casting mould (4) opposite the pouring side (6) and transferred into the outer area (18) and / or - the protective sheath (12) has at least one hole or a plurality of holes through which the sheath material passes radially. [2] Method according to the preceding claim, wherein the component is at least one electrical line (2). [3] Method according to one of the preceding claims, wherein the component is a cable bundle comprising a plurality of lines (2) and in particular a preconfigured cable set. [4] Method according to the preceding claim, wherein the sheath material is introduced only or at least for the most part into the intermediate region (14). [5] Method according to one of the preceding claims, wherein the jacket material passes through the protective cover (12) into the outer area (18). [6] Method according to one of the preceding claims, wherein the protective cover (12) is formed as a fabric. [7] Method according to one of claims 1 to 5, wherein the protective cover (12) is a film. [8] Method according to one of the preceding claims, wherein the protective sheath (12) is tubular, tubular or hollow cylindrical. [9] Method according to one of the preceding claims, wherein the protective cover (12) is spaced from the component by spacers (13). [10] Component, with at least one line (2), which is surrounded by a protective sheath (10) made of a sheath material selected from silicone or an elastomer with an interposition of a protective sheath (12), wherein the protective sheath (10) is formed in an intermediate region (14) between the component and the protective sheath (12) and in an outer region (18) outside the protective sheath (12), wherein the protective sheath (12) is embedded in the sheath material over its entire length, and the protective sheath (12) is penetrated by the sheath material of the protective sheath (10). [11] Component according to the preceding claim, in which the protective casing (10) covers at least one end face of the protective casing (12). [12] Component according to one of the two preceding claims, in which a wall thickness (R1) of the intermediate region (14) is greater than a wall thickness (R2) of the outer region (18), wherein the outer region (18) is preferably formed only as an outer skin with a wall thickness (R2) of a maximum of 2 mm. [13] Component according to one of claims 10 to 12, which is a cable and the at least one line (2) is an electrical line.

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