Contact elements and plug devices, as well as methods for manufacturing and use

Abstract

This offers the potential to reduce the cost and weight of plug connectors. [Solution] The contact element 1 comprises a core 18 made of a conductive first material 22', a shell 20 made of a conductive second material 22" that at least partially surrounds the core 18 from the outside 22", and a coating 64 made of a conductive third material 22''' applied to at least a portion of the outer surface of the shell 20, wherein the first material 22' has a lower density or higher tensile strength than the second material 22" and the third material 22''' is different from the first material 22' and the second material 22". The core-shell structure with a relatively lightweight core makes it possible to reduce the weight of the contact element 1, among other things. Furthermore, the present invention provides a method for manufacturing such a contact element 1 made from a profile material manufactured from at least two materials by extrusion, pressing, or rolling.

Description

[Technical Field]

[0001] The present invention relates to a contact element for a plug device such as a charging plug or a charging socket of a charging system for an electric vehicle. The invention further relates to a method for producing such a contact element, which contact element is produced from a bimetal comprising at least two materials, preferably a co-extruded profile such as a bar. The invention also relates to the use of said bar for producing such a contact element. The invention also relates to a plug device comprising such a contact element. [Background Art]

[0002] Here, electric vehicles are understood to mean, regardless of their size, purely electrically powered vehicles or hybrid vehicles, in particular vehicles having an electric drive as a partial drive such as plug-in hybrids, that is to say passenger cars, trucks and commercial vehicles including vehicles used in agriculture and forestry.

[0003] Plug devices are used in numerous technical fields for forming a detachable connection for the transmission of current and / or signals. This often involves mutual contact between the conductive contact elements of the plug devices that are connected to each other.

[0004] In electromobility applications, some plug devices are for example fixed to a charging station, while other plug devices are part of the electric vehicle and need to be constantly transported together with the vehicle. For this reason, there are various requirements for the plug device and its contact elements. For example, fixed plug devices need to be as inexpensive and robust as possible to achieve a wide-ranging and long-lasting charging infrastructure. For efficiency reasons, vehicle-mounted plug devices need to be as lightweight as possible. [Summary of the Invention] [Problem to be Solved by the Invention]

[0005] Therefore, an object of the present invention is to provide the possibility of reducing the cost and weight of plug connectors. [Means for solving the problem]

[0006] The present objective is to realize the contact element mentioned at the beginning, which comprises a core made of a conductive first material, a shell made of a conductive second material, the shell at least partially surrounding the core from the outside, and a coating made of a conductive third material, the coating at least partially applied to the outer surface of the shell, wherein the first material has a lower density or higher tensile strength than the second material, and the third material is different from the first and second materials.

[0007] Here, density refers to mass density. The third material differs from the first and second materials if it contains at least one component that is lacking in the first and second materials, or if it lacks a component that is present in the first or second materials. In other words, the third material may have a different chemical composition from the first and second materials.

[0008] The advantages realized by the present invention are, on the one hand, based on the core-shell structure of the contact element. This allows for weight reduction by using a relatively lightweight core. If the core is made of a higher strength material, this can contribute to extending the service life of the contact element. This can be achieved, for example, by providing the required conductive cross-section from a more conductive material, while minimizing the loss of current capacity or current load capacity when the shell encloses the core, i.e., surrounds or coats the core from the outside. Because the shell is positioned on the outer periphery of the core, it has a large contact area relative to its conductive cross-section, which reduces contact resistance and improves current capacity or current load capacity.

[0009] On the other hand, the coating can be used to reduce the repair and replacement costs of plug devices featuring the contact elements according to the present invention by extending the service life and maintenance cycle of the contact elements.

[0010] Therefore, the above-mentioned objectives can also be achieved by a plug device comprising at least one contact element and a housing that holds the at least one contact element according to the present invention. The plug device benefits from the functionality and advantages of the present invention, enabling cost and weight reductions.

[0011] The plug device may be a standardized plug device for a charging system for electric vehicles. The charging system may be a DC power supply, an AC power supply, or a three-phase power supply.

[0012] The present invention can be further improved by the following designs, each of which is advantageous in itself and can be combined with one another as needed.

[0013] According to a possible first embodiment, the third material may have higher wear resistance than the first and second materials. In other words, the coating may have higher wear resistance than the core, particularly the shell. This allows the contact element to be used for more charging cycles without repair than without the coating. Wear resistance can be defined, for example, according to ASTM G99.

[0014] Alternatively or as an addition, the third material may have higher conductivity than the first and second materials. In other words, the coating is advantageous because it can conduct current better than the core, especially the shell, which further reduces the contact resistance of the contact elements.

[0015] Furthermore, the shell may have higher conductivity than the core. This means that the second material may have higher conductivity than the first material. High conductivity is generally associated with higher material costs. However, because of the core, the contact element according to the present invention does not have to be made entirely of a more conductive material. This allows for further cost reductions.

[0016] The core-shell structure of the contact element allows for the selection of individual materials as needed. Therefore, by specializing the core, shell, and coating for predetermined sub-functions, maximum cost and weight reduction can be achieved. According to exemplary material selections, the first material may include aluminum, the second material may include copper, and / or the third material may include silver. In other words, the core may be made of aluminum or an aluminum alloy, the shell may be made of copper or a copper alloy, and the coating may be made of silver or a silver alloy. However, the first material may also include zinc and / or iron, and the third material may also include nickel and / or gold.

[0017] According to another possible embodiment, the core and the shell may be cold-welded to each other in at least some areas. In particular, cold welding may be performed at the interface between the core and the shell where a direct metallic joint exists between the first material of the core and the second material of the shell. As will be described in more detail below, cold welding may be achieved, for example, by a cold forming process. This provides a sufficient mechanical bond between the core and the shell without contamination of the second material by the first material due to material migration, as in the case of a diffusion process at high temperatures.

[0018] For use as a contact pin, the contact element can be elongated or pin-shaped, particularly along the principal direction. Here, the elongated contact element has a much larger dimension or extension than the other dimensions or extensions of the contact element, for example, five times, preferably four times, and at least three times.

[0019] According to further possible embodiments, in the first cross-section of the contact element perpendicular to the principal direction, the area ratio of the core to the shell may be at least 3:1. This means that the cross-sectional area of ​​the core is three times larger than the cross-sectional area of ​​the shell. This represents a good compromise between weight reduction of the core and the existing conductor cross-section of the shell. Of course, any other area ratio of the core to the shell may exist in the first cross-section, such as 4:1, 2:1, 1:1, or 1:2.

[0020] Optionally, the contact element may be formed entirely from the second or first material in a second cross section perpendicular to the principal direction. In other words, the contact element may have at least one coreless or shellless portion. In this embodiment, the coreless second cross section extends through this coreless portion and is spaced apart from the first cross section along the principal direction. Advantageously, the coreless portion can be formed particularly thin and therefore preferably located at the tip of the contact element when viewed from the principal direction.

[0021] For example, the aforementioned coreless portion may be configured to attach or hold a touch (or contact) protection cap to the tip of the contact element. Thus, the contact element may include such a touch protection cap configured to attach to the tip of the contact element. In this embodiment, the touch protection cap is made of a non-conductive material for insulation.

[0022] As an addition or alternative, the contact element may be formed entirely from the first material in a third cross section perpendicular to the principal direction. In other words, the contact element may comprise at least one bare core or exposed core portion that is shell-less and lacks a coating or third material. In this embodiment, the third cross section extends through this bare portion and is spaced apart from the first and second cross sections along the principal direction.

[0023] Optionally, the bare portion just described may be arranged on the base portion (extension (German: Ansatz)) of the contact element, said base portion being located on the opposite side of the distal end of the contact element in the main direction. When the contact element is mounted, the base portion faces towards the inside of the plug device, and the distal end of the contact element faces outwards towards the mating plug device of the plug device.

[0024] The bare portion may, for example, perform purely mechanical functions, which is why a shell and coating made of a material with higher conductivity are not required at that location. Of course, especially since the first material of the core is also conductive, the core, particularly the bare portion of the contact element, can also be part of the conductor cross-section.

[0025] In particular, the core may have a fixing portion for a conductor of the plug device. Accordingly, the plug device may have at least one conductor, whereby the core is conductively connected to the at least one conductor. The fixing portion may, for example, be formed by the bare portion of the contact element, and may be provided with a welding surface and / or a thread. Alternatively or additionally, the shell may also have a fixing portion for a current conductor.

[0026] Preferably, the at least one conductor is made of the same first material as the core or the shell. This material uniformity makes the connection between the core or the shell and the at least one conductor less susceptible to galvanic corrosion, which is particularly advantageous from an electrochemical point of view. Accordingly, contact elements with an aluminum-containing core can be particularly suitable for combination with aluminum busbars, so their use is steadily increasing in the field of electromobility. A contact element provided with a shell made of copper or a copper alloy can be made particularly suitable for connection to a copper cable, and its material similarity facilitates, for example, the welding process.

[0027] Alternatively, the core or the first material may also contain copper. Similarly, the shell or the second material may also contain aluminum.

[0028] It is also advantageous if the first material of the core has better weldability and / or machinability than the second material of the shell. This makes it easier to form the fixing portion on the core.

[0029] According to a further possible embodiment, the contact element may have an outer shape deviating from a straight cylindrical body in at least some regions. The outer shape may be defined by the outer contour or the cubature of the contact element. Deviation from the straight cylindrical body provides additional degrees of freedom in design and makes it possible to improve the functionality of the contact element. For example, the contact element may be provided with an insertion bevel at the tip end, which facilitates the contact process. Likewise, the contact element may have a shoulder for fixing the contact element to a housing of a plug connection.

[0030] To achieve a desired outer shape, the contact element may have at least one cross-sectional change portion, that is, a change in cross-section. The at least one cross-sectional change portion may relate to the entire circumference of the contact element measured circumferentially relative to the main direction, in particular to the overall diameter of the contact element measured perpendicular to the main direction. The at least one cross-sectional change portion may be located between the base portion and the tip end of the contact element. For clarity, in the present description, it can be assumed that the base portion is located before the cross-sectional change portion and the tip end is located behind the cross-sectional change portion. From the base portion to the tip end, the at least one cross-sectional change portion may represent a tapered cross-section portion or an enlarged cross-section portion.

[0031] Furthermore, the at least one cross-sectional change portion may be stepped to realize the aforementioned shoulder. Alternatively, the at least one cross-sectional change portion may be gradual, which enables, for example, the aforementioned insertion bevel to be realized. Optionally, the contact element may also have a plurality of such cross-sectional change portions.

[0032] According to further possible embodiments, the first thickness of the shell in front of the cross-sectional change may differ from the second thickness of the shell behind the cross-sectional change. This means that the shell does not have a constant thickness, but rather has different thicknesses on different sides of the cross-sectional change or along the longitudinal axis of the part. Here, the shell thickness, in particular the first and second thicknesses, is measured perpendicular to the principal direction.

[0033] For example, the shell thickness may decrease with the reduction in cross-section and increase with the expansion in cross-section. Preferably, the shell thickness may be proportional to the entire circumference or overall diameter of the contact element. As with the cold welding described above, variable shell thickness can also be achieved by a cold forming process by applying locally different pressing pressures to the contact element.

[0034] Optionally, the contact element may have a flange projecting radially outward with respect to the principal direction. The flange allows the contact element to be geometry-fitted to the housing of the plug device with respect to the principal direction. Furthermore, since the flange does not need to be rotationally symmetric with respect to the principal direction, it also serves to rotatably or rotatably mount the contact element to the housing of the plug device.

[0035] A flange is one of the possibilities for achieving at least one cross-sectional variation. Depending on the requirements, the flange may be formed from a first material of the core and / or a second material of the shell. For example, the flange may be positioned on the bare portion of the contact element and project radially from the exposed core. Alternatively, the flange may be positioned on the shell and project from there.

[0036] The above objectives are also achieved through the manufacturing process of the contact elements. The manufacturing process includes the steps of preparing a profile material or rod comprising a core made of a conductive first material and a shell made of a conductive second material surrounding the core from the outside; forming the profile material or rod into a profiled pin; and coating the pin with a conductive third material, wherein the first material has a lower density than the second material, and the third material is different from the first and second materials.

[0037] The bar material provided may be co-extruded bar material. Alternatively, the bar material may be manufactured by rolling, pressing, and / or welding. The bar material may be formed directly into the final shape of the part by cold forming at a temperature below the recrystallization temperature, or by hot forming at a temperature above the recrystallization temperature.

[0038] The manufacturing process produces contact elements that provide the advantages and functions already described. Therefore, the manufacturing process contributes to reducing the cost and weight of the plug connector. By using bimetal, the core-shell structure of the contact elements can be realized in a simple and cost-effective manner, especially when the pins are manufactured using co-extruded rods, and the final shape can be manufactured in a manufacturing process with multiple integrated steps.

[0039] As a result, the use of a bimetallic, in this case a co-extruded rod for manufacturing a contact element according to one of the embodiments described above, also achieves the above objectives if the co-extruded rod comprises a core made of a conductive first material and a shell made of a conductive second material having a higher density that surrounds the core from the outside.

[0040] Co-extruded rods can be manufactured by an extrusion process in which a first material and a second material are extruded together from a molding die. Depending on the desired shape of the bimetal, the material may be cut to the correct length for manufacturing parts, particularly profile pins, either before or after molding.

[0041] As an alternative to co-extruded rods, a core-shell structure can also be obtained by pressing a solid rod or wire made from a first material with a hollow tube made from a second material. Subsequent shaping into a profile pin ensures that the core or solid rod is cold-welded to the shell or hollow tube, forming a durable, high-strength connection.

[0042] The aforementioned coreless portion can be formed, for example, by ensuring that the hollow tube has an appropriate projection length / excess length relative to the solid rod. In other words, the shell of the profile or rod can be longer than the core of the profile or rod. During cold forming, the projection of the hollow tube is compressed radially to obtain the coreless portion of the contact element. Alternatively (or additionally, if there are appropriate projections on both sides), a conductor can be inserted or fitted into the projection of the hollow tube, thereby enabling conductive connection at that location, for example, to the fixed portion of the core.

[0043] Similarly, the aforementioned bare portion can be formed when the solid rod protrudes from the hollow tube and is not completely covered by the second material of the hollow tube. Therefore, the core of the profile or rod can also be longer than the shell of the profile or rod.

[0044] Another alternative method for manufacturing bimetallic materials may involve a rolling process in which a profile made of a first material is mechanically clad with a second material under pressure to form a shell.

[0045] The above-mentioned objectives can also be achieved by an electric vehicle, the electric vehicle comprising a plug device according to one of the preceding embodiments, wherein the plug device is configured as a charging socket for connecting a charging cable to a charging plug.

[0046] The above-mentioned objective can also be achieved by a charging station for an electric vehicle, the charging station comprising a plug device according to one of the prior embodiments and a charging cable, wherein the plug device is configured as a charging plug for the charging cable for connection to the charging socket of an electric vehicle.

[0047] The charging station may be, for example, a public charging station. In particular, the charging station may be a fast-charging station. The charging station may be configured to charge the energy storage device of an electric vehicle connected via a charging cable, charging plug, and charging socket that are in a charging operation state.

[0048] All references to standards or specifications (e.g., ASTM standards) in this application refer to the version of the corresponding standard or specification that is in effect at the time of filing.

[0049] The present invention will be described in more detail below with reference to drawings of several embodiments. The different features of these embodiments can be combined with each other as needed according to the above description. [Brief explanation of the drawing]

[0050] [Figure 1] This is a schematic perspective cross-sectional view of a contact element according to an exemplary first embodiment. [Figure 2] This is a schematic cross-sectional view of the contact element in Figure 1 along the cross-sectional plane II-II. [Figure 3] This is a schematic cross-sectional view of the contact element in Figure 1 along the cross-sectional plane III-III. [Figure 4] This is a schematic perspective cross-sectional view of a contact element according to an exemplary second embodiment. [Figure 5] This is a schematic perspective view of the steps in the manufacturing process of a contact element according to an exemplary further embodiment. [Figure 6] This is a schematic perspective view of the further steps in the manufacturing process. [Figure 7] This is a schematic perspective view of the further steps in the manufacturing process. [Modes for carrying out the invention]

[0051] First, the schematic structure of possible embodiments of contact element 1 will be described with reference to Figures 1 to 4. Next, the schematic structure of possible embodiments of plug device 2 will be described with reference to Figure 4. Finally, the process for manufacturing contact element 1 will be described with reference to Figures 5 to 7.

[0052] As shown in Figure 1, the contact element 1 may be configured as a contact pin 4. For this purpose, the contact element 1 can extend elongated or pin-shaped along the main direction 6 from the base 8 (extension (German: Ansatz)) to the tip 10. When the contact element 1 is in the mounting state 12, the base 8 faces inward into the plug device 2, and the tip 10 of the contact element 1 faces outward (see Figure 4).

[0053] The elongated contact element 1 has a much larger dimension 14' or extension 16' than the other dimensions 14' or extension 16' of the contact element 1, for example, 5 times, preferably 4 times, and at least 3 times larger.

[0054] Optionally, contact element 1 may be configured to be rotationally symmetric with respect to the principal direction 6. Depending on the application, it may also be considered to use a rectangular parallelepiped shape (not shown) or a prismatic shape (not shown) for contact element 1.

[0055] As can be seen in the partial cross-sectional view of Figure 1, the contact element 1 has a core 18 and a shell 20 that at least partially surrounds the core 18 from the outside. The core 18 is made of a conductive first material 22', and the shell 20 is made of a conductive second material 22'', the first material 22' having a lower density than the second material 22''.

[0056] The core-shell structure of contact element 1 and the relatively lightweight core 18 allow for weight reduction without excessive loss of current capacity or current load capacity. This is because the shell 20 provides the required conductor cross-section 24 and encloses the core 18, i.e., surrounds or wraps around the core 18 from the outside. Therefore, since the shell 20 is positioned on the outer periphery of the core 18, the contact area 26 is large relative to its conductor cross-section 24. This reduces contact resistance and improves current capacity or current load capacity.

[0057] The shell 20 can have higher conductivity than the core 18. This means that the second material 22'' can have higher conductivity than the first material 22'. High conductivity is generally associated with higher material costs. However, because of the core 18, the contact element 1 does not have to be made entirely of a more conductive material. This results in cost savings.

[0058] The core 18 and the shell 20 can be cold-welded to each other in at least some areas. In particular, cold welding may be performed at the interface 28 between the core 18 and the shell 20 where a direct metallic joint exists between the first material 22' of the core 18 and the second material 22'' of the shell 20. As will be described in more detail below, cold welding may be achieved, for example, by a cold forming process.

[0059] As can be seen in Figure 1, the contact element 1 may have an outer shape / outer form 30 that deviates from the straight body in at least some areas. The outer shape 30 can be defined by the outer contour 32 or three-dimensional outer shape 34 of the contact element 1. For example, the contact element 1 may have an insertion bevel (or angle) 36 at its tip 10. Similarly, the contact element 1 may have a shoulder 38 for securing the contact element 1 to the housing 40 of the plug device 2 (see Figure 4).

[0060] In other words, the contact element 1 may have one or more cross-sectional changes 42. Each cross-sectional change 42 may affect the entire circumference 46 of the contact element 1 measured in the circumferential direction 44 with respect to the principal direction 6, and in particular the overall diameter 48 of the contact element 1 measured perpendicular to the principal direction 6. The cross-sectional changes 42 may be stepped, requiring a shoulder 38. Other cross-sectional changes 42 may be progressive, thereby realizing the aforementioned insertion bevel 36.

[0061] The cross-sectional change portion 42 may be positioned between the base 8 and the tip 10 of the contact element 1. In the example shown in Figure 1, the contact element 1 comprises one cross-sectional enlargement portion 50 and three cross-sectional tapered portions 52 as the cross-sectional change portion 42 from the base 8 to the tip 10. Depending on the internal shape of the housing 40 of the plug device 2, there may be different combinations of cross-sectional change portions 42.

[0062] In the first cross-section 54' of the contact element 1 perpendicular to the principal direction 6, the area ratio of the core 18 to the shell 20 can be at least 3:1. Naturally, any other area ratio of the core to the shell in the first cross-section 54' may exist, such as 2:1, 1:1, 1:2, or 1:3.

[0063] Figures 2 and 3 show the front and rear cross-sections 54 of the cross-sectional change section 42, respectively. The first thickness 56' of the shell 20 in front of the cross-sectional change section 42 may be different from the second thickness 56" of the shell 20 behind the cross-sectional change section 42. In other words, the shell 20 does not need to have a constant thickness 56. Rather, it has different thicknesses 56 on different sides of the cross-sectional change section 42. Here, the shell thickness 56, in particular the first thickness 56' and the second thickness 56", can each be measured radially with respect to the principal direction 6 and may represent the distance between the outermost material layer and the innermost material layer. Thus, the shell thickness 56 corresponds to the material thickness of the shell 20.

[0064] Figures 2 and 3 show that the shell thickness 56 may decrease with respect to the tapered section 52, and conversely, that the shell thickness 56 may increase with respect to the enlarged section 50. The shell thickness 56 may be proportional to the entire circumference 46 or the overall diameter 48 of the contact element 1.

[0065] Figure 4 shows a contact element 1 mounted on the housing 40 of the plug device 2. In this embodiment, the contact element 1 of the housing 40 is accessible from the outside for the mating plug (not shown). Depending on the requirements and application, the plug device 2 may have multiple contact elements. If the plug device 2 belongs to a DC charging system, for example, two contact elements may be provided, one as the positive contact (DC+) and the other as the negative contact (DC-). In AC or three-phase charging systems, contact elements are provided on the neutral conductor, protective conductor, and a corresponding number of phase conductors.

[0066] As can be seen in Figure 4, the contact element 1 may have a flange 58 that protrudes radially outward with respect to the principal direction 6. By using the flange 58, the contact element 1 can be held in shape-fit to the housing 40 of the plug device 2 with respect to the principal direction 6. Furthermore, since the flange 58 does not need to be rotationally symmetric with respect to the principal direction 6, the flange 58 also serves to rotatably fix or rotatably mount the contact element 1 to the housing 40 of the plug device 2.

[0067] In the example shown in Figure 4, the flange 58 is formed from the second material 22'' of the shell 20. In particular, the flange 58 is positioned on the shell 20 and can protrude from it. Alternatively, the flange 58 may be formed from the first material 22' of the core 18. For example, the flange 58 may be positioned on a bare portion (not shown) of the contact element 1 without the shell 20, and may protrude radially from the exposed core 18. A further alternative option is a plastic flange (not shown) molded onto the contact element 1.

[0068] Optionally, the flange 58 may have a retaining pocket 60 for a temperature sensor (not shown). Following the flange 58 in the main direction 6, a seal ring 62 may be positioned on the contact element 1, for example, by an overmolding.

[0069] The contact element 1 includes a coating 64 made of a conductive third material 22'' applied to at least a portion of the outer surface of the shell 20. Preferably, the coating 64 is located at the tip 10 of the contact element 1. In particular, the coating 64 may be limited to the tip 10. If necessary, the coating may also be applied to the base 8.

[0070] The third material 22''' differs from the first material 22' and the second material 22" in that the third material contains at least one component that is lacking in the first material 22' and the second material 22'', or that a component present in the first material 22' or the second material 22'' is lacking in the third material 22'''.

[0071] For example, the third material 22''' may have higher conductivity than the first material 22' and the second material 22''. In other words, the coating 64 can conduct electricity better than the core 18, and especially the shell 20, thereby advantageously reducing the contact resistance of the contact element 1.

[0072] As an alternative or addition, the third material 22'' may have higher wear resistance than the first material 22' and the second material 22''. In other words, the coating 64 may have higher wear resistance than the core 18, and especially the shell 20. Thus, the contact element 1 can be used for more charging cycles without repair than without the coating. Wear resistance can be defined, for example, according to ASTM G99.

[0073] According to exemplary material selections, the first material 22' may contain aluminum, the second material 22'' may contain copper, and / or the third material 22'''' may contain silver. In other words, the core 18 can be made of aluminum or an aluminum alloy, the shell 20 can be made of copper or a copper alloy, and the coating 64 can be made of silver or a silver alloy.

[0074] As can be seen in Figure 4, the contact element 1 may be formed entirely from the second material 22" in a second cross section 54" perpendicular to the principal direction 6. In other words, the contact element 1 may have at least one coreless portion 66 without a core 18. In this embodiment, the second cross section 54" extends through this coreless portion 66 and is separated from the first cross section 54' along the principal direction 6. As described, the coreless portion 66 can be formed particularly thin and is therefore preferably located at the tip 10 of the contact element 1.

[0075] In particular, the coreless portion 66 may be configured to attach or hold a touch protection cap 68 to the tip portion 10 of the contact element 1. Thus, the contact element 1 may have such a touch protection cap 68 attached to the tip portion 10 of the contact element 1. The touch protection cap 68 is made of a non-conductive material for insulation.

[0076] As already shown, the contact element 1 may have a bare core without a shell or a portion of the exposed core. This bare portion allows the contact element 1 to be formed entirely from the first material 22' in a third cross section (not shown) perpendicular to the principal direction 6. The third cross section extends through the bare portion and is separated from the first cross section 54' and the second cross section 54'' along the principal direction 6.

[0077] Figure 4 also shows that the plug device 2 may have a conductor 70 which may preferably be made of the same first material 22' as the core 18 to avoid galvanic corrosion. The core 18 may be electrically connected to at least one conductor 70. For this purpose, the core 18 may have a fixing portion 72 for the conductor 70. The fixing portion 72 may provide, for example, a weld surface 74. Alternatively or additionally, the fixing portion 72 may have threads (not shown). Therefore, to facilitate the realization of the fixing portion 72, it is advantageous if the first material 22' of the core 18 has better weldability and / or better machinability than the second material 22'' of the shell 20.

[0078] If the plug device 2 conforms to a standard or specification, the shape 76 of the contact element 1, particularly the tip portion 10, may, at least in part, correspond to the shape specified in this standard or specification. Furthermore, the coating 64 may be applied to the contact area 26 in accordance with the method specified in this standard or specification.

[0079] The manufacturing process for contact element 1 is described below. As shown in Figure 5, the manufacturing process first includes the step of preparing a co-extruded rod 78 comprising a core 18 made of a first material 22' and a shell 20 made of a second material 22''.

[0080] As an alternative to the co-extruded rod 78, a core-shell structure can also be obtained by pressing a solid rod (not shown) made of the first material 22' and a hollow tube (not shown) made of the second material 22'' together. Another alternative to the co-extruded rod 78 may be to form a shell 20 on top of a solid rod made of the first material 22' by cladding it with the second material 22''.

[0081] This is followed by the step shown in Figure 6, in which the rod 78 is cold-formed into a profile pin 80. Cold forming ensures that the shell 20 is held together with the core 18 by cold welding. The area of ​​the pin 80 in which the circumference 46 or overall diameter 48 is particularly significantly reduced is subjected to higher pressure than the rest of the pin 80. As a result, in the finished contact element 1, the shell thickness 56 is proportional to the circumference 46 or overall diameter 48 of the contact element 1.

[0082] Figure 7 shows the subsequent steps of coating pin 80 with the third material 22'''. However, the spray coating shown should be understood as merely an example. Other coating methods such as electroplating, vacuum coating (PVD / CVD), dip coating, powder coating, and flame spraying are also possible and intended. [Explanation of Symbols]

[0083] 1. Contact element 2 Plug devices 4 Contact pins 6 Main Direction 8 base 10 Tip 12 Installation status 14, 14' dimensions 16, 16' extension 18 cores 20 shells 22' 1st material 22” 2nd material 22''' 3rd material 24 Conductor cross-section 26 Contact area 28 Interface 30 External shape 32 Outer contour 34 Three-dimensional external shape 36 Insertion Bevel 38 Shoulder 40 Housing 42 Sectional change area 44 Circumferential direction 46 All around 48 overall diameter 50 Enlarged cross-section 52 Tapered section 54 Cross-section 54' 1st section 54” 2nd section 56 Thickness 56' First thickness 56” 2nd thickness 58 Flange 60 retention pockets 62 Seal rings 64 Coating 66 core-less portion 68 Touch Protection Cap 70 Conductor 72 Fixed part 74 Welding Mask 76 Shape 78 Bar material 80 profile pins

Claims

1. A contact element (1) for a plug device (2) such as a charging plug or charging socket, wherein the contact element (1) is - A core (18) made of a conductive first material (22'), - A shell (20) made of a conductive second material (22"), wherein the shell (20) surrounds the core (18) from the outside, - A coating (64) made of a conductive third material (22''), wherein the coating (64) is applied at least partially to the outer surface of the shell (20), and Equipped with, Contact element (1), wherein the first material (22') has a lower density or higher tensile strength than the second material (22"), and the third material (22'') is different from the first material (22') and the second material (22").

2. The contact element (1) according to claim 1, wherein the third material (22''') has higher wear resistance and / or higher conductivity than the first material (22') and the second material (22'').

3. - The first material (22') comprises aluminum, copper, zinc, and / or iron. - The second material (22") comprises aluminum and / or copper, and / or - The contact element (1) according to claim 1 or 2, wherein the third material (22'') comprises silver, nickel and / or gold.

4. The contact element (1) according to any one of claims 1 to 3, wherein the core (18) and the shell (20) are cold-welded to each other in at least a portion of the area.

5. The contact element (1) according to any one of claims 1 to 4, wherein the contact element (1) extends along the principal direction (6), and in a first cross section (54') of the contact element (1) perpendicular to the principal direction (6), the area ratio of the core (18) to the shell (20) is at least 4:

1.

6. The contact element (1) according to claim 5, wherein the contact element (1) is formed entirely from the second material (22") in a second cross section (54") perpendicular to the principal direction (6), and / or is formed entirely from the first material (22') in a third cross section perpendicular to the principal direction (6).

7. The contact element (1) according to any one of claims 1 to 6, wherein the core (18) or the shell (20) has a fixing portion (72) for the conductor (70) of the plug device (2).

8. The contact element (1) according to any one of claims 1 to 7, wherein the contact element (1) has an outer shape (30) that deviates from the straight body portion in at least a portion of the area.

9. The contact element (1) according to any one of claims 1 to 8, wherein the contact element (1) has at least one cross-sectional change portion (42).

10. The contact element (1) according to claim 9, wherein the first thickness (56') of the shell (20) in front of the cross-sectional change portion (42) is different from the second thickness (56'') of the shell (20) behind the cross-sectional change portion (42).

11. The contact element (1) according to any one of claims 1 to 10, wherein the contact element (1) has a flange (58) formed from the first material (22') and / or the second material (22'').

12. A plug device (2) comprising at least one contact element (1) according to any one of claims 1 to 11, and a housing (40) in which the at least one contact element (1) is held.

13. The plug device (2) according to claim 12, wherein the plug device (2) has at least one conductor (70) made of the same first material (22') as the core (18) of the at least one contact element (1), and the core (18) of the at least one contact element (1) is electrically connected to the at least one current conductor (70).

14. The plug device (2) according to claim 13, wherein the shell (20) of the at least one contact element (1) is longer than the core (18) of the at least one contact element (1), and the at least one conductor (70) is inserted into or fitted into the shell (20) of the at least one contact element (1).

15. A method for manufacturing a contact element (1), - A step of preparing a profile material or rod material (78) comprising a core (18) made of a conductive first material (22') and a shell (20) made of a conductive second material (22''), wherein the shell (20) surrounds the core (18) from the outside, - The step of forming the profile material or rod material (78) into a profile pin (80), - A step of coating the pin (80) with a conductive third material (22'') and Includes, A method for manufacturing a contact element (1), wherein the first material (22') has a lower density than the second material (22"), and the third material (22''') is different from the first material (22') and the second material (22").

16. The manufacturing method according to claim 15, wherein the shell (20) of the profile material or rod material (78) is longer than the core (18) of the profile material or rod material (78).

17. Use of a co-extruded rod (78) comprising a core (18) made of a conductive first material (22') and a shell (20) made of a conductive second material (22''), wherein the shell (20) surrounds the core (18) from the outside (22'') and has a higher density or lower tensile strength for manufacturing a contact element (1) for a plug device (2).

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