Contact assembly, which is detachably placed together, for plug connections

Abstract

The invention relates to a contact assembly for plug connections, i.e. charging plugs for transmitting electrical power, having at least two contact assembly elements, at least one connecting element, and at least one securing element, wherein the at least two contact assembly elements are positioned so as to be axially aligned in the longitudinal direction of the contact assembly and are detachably placed together at one of the end faces thereof, the connecting element is formed by a wire thread insert, a contact assembly element has a threaded bore into which the wire thread insert is screwed, and the wire thread insert interacts with a securing element such that the contact assembly elements placed together are detachably connected so as to be stable over the long term.

Description

[0001] November 19, 2025

[0002] -1-

[0003] Description

[0004] Detachable, assembled contact arrangement for plug connections

[0005] The invention relates to a contact arrangement for plug connections, charging plugs for the transmission of electrical power, comprising at least two contact arrangement elements as well as at least one connecting element and at least one fastening element, wherein the at least two contact arrangement elements are arranged axially aligned in the longitudinal direction of the contact arrangement and are detachably joined together at one of their end faces.

[0006] Contacts generally have at least one electrically conductive contact section for detachable, temporary, or plug-in connection with a corresponding mating contact element and a shaft section adjoining the contact section for attaching an electrical conductor to the contact. Such a contact, plug-in contact, or high-current contact can be used, for example, on a charging plug or socket for charging an electric vehicle. In this case, a cable is connected to a charging station on one side and carries a connector part in the form of a charging plug on the other, which can be inserted into a corresponding mating connector part in the form of a charging socket on a vehicle to establish an electrical connection between the charging station and the vehicle.

[0007] Charging currents can generally be transmitted as direct currents or as alternating currents, whereby charging currents and high-current areas in the form of direct current in particular have a large current intensity, for example greater than 200 A or even greater than 300 A or even 350 A, and can lead to heating of the cable as well as of a high-current contact connected to the cable.

[0008] During the charging process of electrical energy storage devices, such as batteries, heat is generated due to the high electrical power and currents transmitted. This heat is not only generated in the cable connecting a charging plug to a charging station, but also in the charging plug itself, and especially within the charging plug, for example, at high-current contacts. These contacts establish an electrical connection with corresponding mating contacts, such as those on the charging socket side of an electric vehicle, when the charging plug is inserted and electrical power is transferred. November 19, 2025

[0009] -2-

[0010] High-current contacts made of electrically conductive materials, such as copper alloys, heat up when a charging current flows through them. Therefore, the contacts must be dimensioned according to the charging current to be transmitted, ensuring sufficient current-carrying capacity and limiting heating of the contact elements. The larger the charging current, the larger the contact should be. However, scaling the contact element size with increasing charging current is limited by the associated space requirements, weight, and cost. Consequently, there is a need to transmit a high charging current with a comparatively small contact.

[0011] High charging currents are of particular importance in the context of the planned electromobility. Only in this way can electric vehicles, or rather their energy storage systems, be "refueled" in a short time.

[0012] A generally known solution approach in the prior art is to design the contacts, particularly the high-current contacts of charging plugs, as two- or multi-part components. This achieves the necessary dimensions for electrical power transmission, limits heat generation, and reduces power losses. For example, such contact arrangements can consist of a contact element for contacting a mating contact element and a contact carrier element for contacting an electrically conductive cable. Optionally, the contact element and the contact carrier element can be connected by a connecting element. This connecting element can be an integral part of the contact carrier element and / or the contact element, or it can be designed as a separate, and potentially multi-part, connecting element.

[0013] Detachable connection techniques in the form of threaded pairings using internal and external threads have proven particularly advantageous because such connections can be both detachable and high-strength with a long service life. November 19, 2025

[0014] EP 3446369 B1 discloses a power contact for a charging plug and / or a charging socket for the transmission of electrical energy, wherein the power contact is formed in at least two parts and comprises a base component and a contacting component connectable to the base component, the contacting component being detachable from the base component so that the contacting component of the power contact is replaceable. The first connection area is arranged in the contacting component, and the second connection area is arranged in the base component. When the contacting component is connected to the base component, the first and second connection areas are in galvanic contact. The detachable design of the contacting component and the base component is achieved by a connecting element in the form of a threaded sleeve that is materially separated from the base component.

[0015] The multi-part design makes it possible to separate and renew the contact element subject to wear from the contact carrier element and to continue using the contact carrier element that is not subject to any significant wear.

[0016] Two- or multi-part contact arrangements, which are preferably detachably joined by at least one connecting element, are described, for example, in US 6,220,902 B1, in US 2009 / 0090517 A1, in DE 69313729 T2 and in US 2,917,722 A.

[0017] The detachable connection of at least two elements of a contact arrangement, consisting of at least one contact element and at least one contact carrier element, is subject to special requirements. The connection technology must ensure that the connection is durable in the sense of long-term stability and withstands various stresses such as static and / or dynamic mechanical forces and torques, vibrations, and thermal and / or mechanical-dynamic shock loads.

[0018] Furthermore, the materials used in contact elements and contact carrier elements present particular challenges for connection technology. Their primary requirement of transmitting electrical power with minimal loss often necessitates the use of highly electrically conductive materials, such as copper alloys or pure copper. Such materials do not possess, or do not possess to a sufficient degree, the mechanical or material-inherent properties required to achieve the desired performance.

[0019] -4-

[0020] Requirements for the connection between contact elements and contact carrier elements. Furthermore, for the most efficient electrical power transmission possible, the available cross-sectional area of ​​the contact elements and contact carrier elements must be as large as possible. This means that the cross-sectional area required for the connection structure within the contact elements and contact carrier elements must be as small as possible.

[0021] Therefore, solutions for connecting elements based on a sleeve-like arrangement, as shown in EP 3446369 B1, do not represent an ideal joining technology because a sleeve with internal and external threads must have a sufficiently large ring cross-section, which reduces the available cross-section of the contact elements and contact carrier elements.

[0022] To make matters worse, the sleeve material must have high-strength properties due to the connection requirements, which are often reduced in their electrical conductivity.

[0023] The object of the invention is to further develop existing detachable connection solutions for contact arrangements with at least two-part construction, so that the aforementioned disadvantages of the prior art are at least partially reduced and the long-term stable fatigue strength of the detachable connection is improved.

[0024] To solve this problem, the invention proposes a connecting element, designed as a wire thread insert, which is incorporated into a threaded bore of one of the at least two contact arrangement elements. In this way, the wire thread insert forms a separate component, at least before its assembly into the threaded bore of a contact arrangement element.

[0025] Preferably, a spirally wound wire coil is inserted into a correspondingly pre-cut thread in the base body, and then the fastening element (e.g., screw or touch protection pin) is inserted into the wire coil and tightened with a tightly toleranced torque. November 19, 2025

[0026] -5-

[0027] Furthermore, the connecting element has a fastening element, designed as a fastening screw with an external thread, which can be screwed into the threaded hole of one of the at least two contact assembly elements. The fastening element is positioned by an axial bore of the contact assembly element without a threaded insert such that it can be screwed into the threaded hole with the threaded insert of the contact assembly element equipped with it. The clamping force of the formed thread pair clamps the contact assembly elements against each other, thus ensuring a long-term stable connection.

[0028] The relative dimensioning of the fasteners can be achieved in various ways. One possibility is that an internal thread corresponding to a standardized thread diameter is formed by inserting the wire thread insert into the threaded hole of a contact assembly element. In this case, a fastener with a standardized external diameter compatible with the standardized thread diameter can be inserted. For this to work, the threaded hole for screwing in the wire thread insert must have an internal thread diameter that is matched to the wire diameter of the wire thread insert. This means that the threading tool used to create the threaded hole deviates from the standard diameter of the fastener, in particular, it is larger.

[0029] Another possibility is to build the pairing of the connecting elements based on a threaded bore with a standardized inner diameter within a contact assembly element, so that the thread inner diameter formed by the wire thread insert deviates from a standard inner diameter and the fastening element also has a compatible, non-standard thread outer diameter.

[0030] The inventive solution for connecting the contact arrangement elements offers several advantages. Due to the small cross-sectional area of ​​the wire thread insert relative to the axial cross-section of the connecting element, compared to known connection solutions, such as a threaded sleeve, the cross-sectional area of ​​the contact arrangement available for conducting electrical power in this area is significantly reduced. (November 19, 2025)

[0031] -6-

[0032] This increases the electrical resistance and thus reduces power loss during electrical energy transmission. The increased cross-sectional area of ​​the contact arrangement also enhances its overall thermal conductivity, which is particularly relevant for any cooling capacity that may be required, for example, in contact arrangements for high-current applications.

[0033] A further advantage is that the reduced cross-sectional area required for the wire thread insert decreases its contribution to electrical power conduction, thus making its current-conducting properties less critical. This allows the wire thread material to be optimized for its required strength properties, resulting in a particularly high-strength, long-term stable, detachable connection of the contact assembly elements.

[0034] Due to the special property of wire thread inserts to even out the load-bearing portion of the threads in the axial direction, the axial clamping capacity is significantly increased. Unlike conventional thread pairings, for example, formed by a screw with an external thread and a threaded bushing with an internal thread, where a significant portion of the axial clamping force is applied by the first threads in the screw-in direction, a wire thread insert is able to distribute the axial loads of the threads considerably further, thus reducing the maximum load on individual threads.

[0035] The clamping capacity is further increased by using a wire thread insert due to the enlarged threaded bore for accommodating the wire thread insert within the contact assembly element. The increased thread bore diameter results in a disproportionately larger shear area of ​​the threads relative to the bore diameter, thus significantly increasing the thread load-bearing capacity.

[0036] The high-strength and long-term stable detachable connection achieved through the connection arrangement and the use of a wire thread insert advantageously results in improved resistance to various stresses such as dynamic vibrations, thermal cycling, and dynamic or thermal peak loads. November 19, 2025

[0037] -7-

[0038] Furthermore, the invention utilizes the possibility of influencing the surface texture and surface finish of the wire thread insert independently of the surface design of the threaded bore in the contact assembly element and fastening element. By designing for high abrasion resistance and reduced surface friction (for example, through surface hardening and / or low roughness), the high tightening torque required for a high and / or precisely adjustable connection preload force can be reduced. This allows a very high axial preload level to be achieved even with lower permissible torsional load limits of the connection. At the same time, the preload force can be adjusted within narrow limits, so that the contact assembly elements can be structurally optimized for electrical conductivity and / or thermal expansion behavior.

[0039] The invention is explained in more detail below with reference to an exemplary embodiment in conjunction with the figures. These show:

[0040] Fig. 1 shows a sectional side view of a contact arrangement 1 essentially consisting of at least two contact arrangement elements 2 and at least one connecting element 6;

[0041] Fig. 2 shows a wire spiral wound in a spiral shape.

[0042] In the exemplary embodiment shown, the contact arrangement elements 2 of the contact arrangement 1 are formed by a contact element 3, shown here as a contact socket, and a contact carrier element 4. The contact element 2, 3 and the contact carrier element 2, 4 are each detachably joined together at one of their axial end faces and held in the joined position relative to each other by at least one connecting element 6 and at least one fastening element 8.

[0043] Due to the contact element design consisting of at least two parts, it is possible for the wear-prone contact element 2, 3 to be separable and replaced while simultaneously continuing to use the contact carrier element 2, 4. November 19, 2025

[0044] -8-

[0045] The contact assembly elements 2 are held in a detachable position relative to each other by mutual axial clamping via a connecting element 6, which interacts with a fastening element 8. The connecting element 6 is formed by a wire thread insert 7, which is screwed into a threaded bore 5 that extends axially within a contact assembly element 2, in this case the contact carrier element 4. In the assembled arrangement of the contact assembly elements 2, 3, 4, the threaded bore 5, with its axial extension, is aligned with a through bore 5', also extending axially, within the contact element 3.

[0046] In a particularly advantageous embodiment of the invention, the fastening screw 9 can be designed in a high-strength embodiment, for example with a tensile strength of at least 1,000 Nm / mm or 1,200 Nm / mm, and combined with a wire thread insert 7 made of a high-strength material, for example X5CrNi18-10 or NiCr20Co18Ti, to achieve a long-term stable and high-strength, detachable connection of the contact arrangement elements 2.

[0047] The functional realization of the long-term stable and highly resilient connection via the connecting element 6, 7 and the fastening element 8, 9 makes it possible to optimize the contact arrangement elements 2, 3, 4 for their primary functions of minimal loss in electrical energy conduction and good thermal conductivity. High-strength materials are generally less suitable for these objectives because materials with lower tensile strength and / or hardness, such as copper alloys and / or pure copper, exhibit particularly good electrical conductivity and thermal conductivity.

[0048] The fastening element 8 is equipped with an external thread 10 that can be screwed into the internal thread of the wire thread insert 7 and is screwed into the internal thread of the wire thread insert 7 through the through-hole 5' with its external thread 10. By tightening the threaded pair formed in this way, an axial clamping force is generated on the face between the contact arrangement elements 2, 3, 4. In the illustrated embodiment, the fastening element 8 is formed by a through-bolt 9, the head of which has a tool receptacle, for example, November 19, 2025.

[0049] in the form of an internal or external hexagon, is axially accessible on the side of the contact element 2, 3 and may optionally have a collar on the screw head. mber 2025

[0050] -10-

[0051] Reference symbol list

[0052] 1 Contact arrangement

[0053] 2 Contact arrangement element

[0054] 3 Contact element

[0055] 4 Contact carrier element

[0056] 5 threaded holes

[0057] 5' through hole

[0058] 6 Connecting element

[0059] 7 Wire thread insert

[0060] 8 Fastening element

[0061] 9 fastening screw

[0062] 10 external threads

Claims

November 19, 2025 -1- Claims 1. Contact arrangement (1) for plug connections, charging plugs for the transmission of electrical power, comprising at least two contact arrangement elements (2) as well as at least one connecting element (6) and at least one fastening element (8), wherein the at least two contact arrangement elements (2) are arranged axially aligned in the longitudinal direction of the contact arrangement (1) and are detachably joined together at one of their end faces, characterized in that the connecting element (6) is formed by a wire thread insert (7) and a contact arrangement element (2) has a threaded bore (5) into which the wire thread insert (6, 7) is screwed, wherein the wire thread insert (6, 7) cooperates with a fastening element (8) so that the joined contact arrangement elements (2) are connected in a long-term stable and detachable manner.

2. Contact arrangement (1) according to claim 1, characterized in that the wire thread insert (6, 7) screwed into the threaded bore (5) forms an internal thread.

3. Contact arrangement (1) according to claim 1, characterized in that the contact arrangement element (2) with the threaded bore (5) for screwing in the wire thread insert (6, 7) is a contact carrier element (4).

4. Contact arrangement (1) according to claim 1, characterized in that the contact arrangement element (2), which is detachably joined to the contact carrier element (2, 4) at the end face, is a contact element (3) that is preferably a contact socket.

5. Contact arrangement (1 ) according to claim 1, characterized in that the contact element (2, 3) has a through-hole (5').

6. Contact arrangement (1) according to claims 2 and 5, characterized in that the fastening element (8) is a fastening screw (9) with an external thread (10) having at least a portion of its surface, which is inserted into the through-hole (5') of the contact element (2, 3) and screwed into the internal thread of the wire thread insert (6, 7) with the external thread (10). November 19, 2025 -2- 7. Contact arrangement (1) according to claim 6, characterized in that the fastening screw (8, 9) has a tensile strength of at least 1,000 Nm / mm or 1,200 Nm / mm.

8. Contact arrangement (1) according to claim 1, characterized in that the wire thread insert (6, 7) is made of a material X5CrNi18-10 or NiCr20Co18Ti.

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