Method, connecting arrangement and use of a connecting arrangement for at least two stranded lines

Abstract

The invention relates to a method for connecting at least two stranded lines to a busbar, in which method the at least two stranded lines are provided, each stranded line having an end region in which the individual wires of the stranded line are free of insulation, a sleeve is pushed onto each end region, each sleeve is pressed onto the individual wires, each of the connecting regions are placed onto the busbar at two spaced-apart contact regions, the contact regions being on a common first side of the busbar, and, starting from a second side of the busbar opposite the first side, the sleeve, the individual wires and the busbar being welded together at each contact region.

Description

[0001]September 21, 2023 Method, connection arrangement and use of a connection arrangement for at least two stranded wires The subject matter relates to a method for connecting at least two stranded wires to a busbar and a corresponding connection between two stranded wires and a busbar as well as a use of such a connection arrangement. The connection of several electrical wires to a potential busbar in a confined space, in particular a material connection, is challenging with regard to the connection technology as well as the quality and durability of the connection. In particular, when connecting aluminum stranded wires to metallic busbars made of aluminum or copper, known connection methods, e.g.When using laser welding, weakening of the individual wires due to the temperature introduced by the laser around the welding zone, particularly in the longitudinal direction of the individual wires, at a distance from the actual welding zone, can occur. Such weakening of the individual wires during the connection of the cables to the busbar has disadvantages regarding the durability of the connection, especially in dynamic environments. Fatigue bending loads can lead to increased strand breakage due to the initial damage to the individual wires. kommen.Cables connected to a busbar are typically several centimeters to several meters long. Such cables cannot be connected to the busbar using rotational friction welding. It is impossible to rotate such long cables during welding. On the other hand, as soon as a second cable is placed on a busbar, the busbar can no longer be rotated around this second cable. This rules out rotational friction welding as a connection technology. Ultrasonic welding is also problematic if multiple connections are to be made on a busbar using ultrasonic welding. An existing ultrasonic weld seam will be negatively affected, damaged, or destroyed by the ultrasonic vibrations of a subsequent welding process.Therefore, stranded wires on busbars cannot be reliably connected by ultrasonic welding if several of these stranded wires are to be contacted and the welding points are spatially close to one another. The object of the invention was therefore to provide a welding method that enables the permanent, stable, and integral connection of several stranded wires on a common busbar. This object is achieved by a method according to claim 1. It is proposed to provide at least two stranded wires. Stranded wires are wires with several individual wires that are not separately insulated from one another. The individual wires can be woven, stranded, and / or twisted. The individual wires are metallic, in particular formed from a transition metal. Aluminum or copper, as well as aluminum alloys or copper alloys, are particularly suitable as materials for the individual wires.The individual wires of the stranded cables can be covered with a common insulation. A combination of the above-mentioned materials is also possible. möglich. Each stranded wire has two distal ends. One end can have an end region in which the individual wires of the stranded wire are free of insulation. To avoid misunderstandings, it should be clarified that a stranded wire can also be completely free of insulation. Preferably, the stranded wire is part of a cable, wherein the cable is formed at least from the stranded wire and the insulation. W / PW 220317WOSeptember 21, 2023 Insulation is missing in an end region, in particular, it has been removed there. An end region can extend from a front end of the stranded wire to the center of the stranded wire and in particular have a longitudinal extension of between 0.5 cm and 5 cm or more. An insulating material can in particular be silicone, PVC, XLPE, PTFE, PES, PE, or the like. It is proposed that a sleeve be pushed onto an end region of a respective stranded wire. A sleeve can be pushed onto a stranded wire at only one end region or at both distal end regions. Each stranded wire that is physically contacted with the busbar has a pushed-on sleeve at at least one of its end regions. The sleeve is preferably metallic, in particular made of the same material as the stranded wire and / or the busbar. The sleeve can also be made of a different material than the stranded wire and / or the busbar.The sleeve can be made of aluminum, copper, an aluminum alloy or a copper alloy. sein.The sleeve can be pushed from the front end of the stranded cable over the individual wires of the stranded cable. The sleeve is preferably pushed onto the end region in the longitudinal direction of the stranded cable. As will be described below, the sleeve can be formed as a single-piece component or as a multi-piece component. The sleeve has a longitudinal opening into which the individual wires of the stranded cable are inserted. The sleeve can also be formed from a band that is placed circumferentially around the individual wires of the stranded cable in the end region and, if necessary, welded. After the sleeve has been pushed onto the respective end region, it is proposed that the respective sleeve be pressed onto the individual wires. For this purpose, the sleeve is radially compressed (pressed). The sleeve connects to the individual wires in a force-fitting and form-fitting manner by moving the opening of the sleeve radially inward. W / PW 220317WOSeptember 21, 2023. When the sleeve is pressed onto the individual wires, the individual wires can be compacted. The individual wires are preferably compacted to achieve a degree of compaction of more than 90%, preferably more than 95%, in particular more than 98%. The degree of compaction preferably results from the ratio of the metallic cross-sectional area to the cross-sectional area with air inclusion, preferably in a cross-section perpendicular to the longitudinal axis of the stranded wire. A single wire has a cross-sectional area of ​​4*DDir² / π. The cross-sectional area of ​​all N individual wires is N*4*DDir² / π. The cross-sectional area of ​​the sleeve results from the difference between the cross-sectional area at the outer diameter (Doutside) of the sleeve (4*Doutside² / π) and the cross-sectional area at the inner diameter (Dinside) of the sleeve (4*Dinside² / π), i.e. (4*Doutside² / π)-(4*Dinside² / π).The total cross-sectional area of ​​the stranded wire with the individual wires and the sleeve, without air inclusions, is (4*DDir² / π) + ((4*Doutside² / π)-(4*Dinside² / π)). This is the cross-sectional area of ​​the. of the pressed sleeve including wires and any remaining air inclusions is (4* Dpressed² / π). The degree of compaction results from the quotient of the total cross-sectional area and the cross-sectional area of ​​the pressed sleeve, i.e. 2 2 2 (4 ∗ (DDire π)) + ((4 ∗ Dau π ßen ) − ( 4 ∗ Din π nen )) In short, the degree of compaction is:DDraht2 + ^^ ^^ ^^ß ^^ ^^2 − ^^ ^^ ^^ ^^ ^^ ^^²^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^² P W / PW 220317WOSeptember 21, 2023. Assuming that the sleeve and wires are not axially stretched during pressing, a fully pressed sleeve, without air inclusions, results in a degree of compaction of 1 (100%). It is proposed that the degree of compaction be between 90% and 100%, preferably between 95% and 100%, in particular between 98% and 100%. However, it is conceivable, and also proposed, that at least the sleeve is axially stretched during pressing. This results in the value ^^ ^^ ^^ß ^^ ^^2 − ^^ ^^ ^^ ^^ ^^ ^^² being smaller for a pressed sleeve than for the unpressed sleeve. This, in turn, means that the pressed sleeve has a cross-sectional area that is smaller than the total cross-sectional area in the unpressed state. The degree of compaction is then greater than 100%.It is proposed that by axially stretching the sleeve during pressing, a degree of compaction of greater than 100% is achieved, in particular between 100% and 110%, preferably between 100% and 105%, in particular between 100% and 102%. After the sleeve has been pressed onto the individual wires, the respective sleeve, preferably together with the individual wires, is cut to length at the end face such that the individual wires and the sleeve essentially form a planar connection area at the end face of the sleeve. The connection area preferably lies in a plane perpendicular to the longitudinal axis of the stranded wire. The connection area is preferably planar, formed from the end face of the cut-to-length sleeve and the end face of the cut-to-length individual wires of the stranded wire. The cutting to length is preferably such that all individual wires of the stranded wire are cut to length.Thus, all individual wires that may protrude longitudinally from the end face are cut to length, so that all individual wires rest against the connecting area at the end face and span a common plane with the end face of the sleeve. Cutting to length is preferably done by laser cutting. However, cutting to length can also be done by milling or sawing. If necessary, the end face of the individual wires and the sleeve can also be cut to length by grinding, so that P. W / PW 220317WOSeptember 21, 2023, the connection area is formed. It is also possible to carry out the cutting using a combination of the aforementioned methods. The sleeve and the individual wires arranged therein are then placed onto the busbar with their connection area. As already explained in the introduction, at least two stranded wires and two sleeves are provided. The explanations for one sleeve and individual wires naturally apply to all at least two stranded wires with a sleeve. It should be noted that the respective process steps in this document are sometimes only described for one stranded wire and / or one sleeve. It should be noted that the process steps preferably apply to all sleeves connected to the busbar, but at least to two sleeves and stranded wires connected to the busbar.In this respect, the term "respective" is sometimes used to express that not just one, but several sleeves and stranded wires are connected with their connecting areas to spaced-apart contact areas of the busbar. It is proposed that the respective connecting areas be placed on the busbar in spatially spaced-apart contact areas. werden.The busbar has an area in which the stranded wires are to be attached. In this area, at least two spatially spaced contact areas are provided, which are intended to receive the connecting areas of the respective stranded wires. The connecting areas are placed on the two spaced-apart contact areas. The number of contact areas corresponds to the number of connecting areas, i.e., with two stranded wires, there are two contact areas, and with N stranded wires, there are N contact areas, with N ∈ ℕ. PW / PW 220317WO September 21, 2023 It is proposed that the contact areas be arranged on a common side of the busbar. The connecting areas are placed on a common side on the contact areas of the busbar. The busbar is preferably formed as a flat part and has two wide surfaces that lie opposite one another. These wide surfaces preferably run parallel to one another.The contact areas preferably lie on a common, wide surface. The busbar is preferably metallic, in particular made of the same material as the stranded wire and / or the sleeve. The busbar can also be made of a different material than the stranded wire and / or sleeve. The busbar can be made of aluminum, copper, an aluminum alloy, or a copper alloy. The connecting areas are placed on the contact areas. The sleeve, including the individual wires, are then welded to the busbar. It is proposed that, starting from a second side of the busbar opposite the first side, the sleeve, the individual wires, and the busbar be welded together in a respective contact area. This means that the welding takes place starting from the second side opposite the first side.As will be explained below, various welding methods are suitable for this purpose: on the one hand, in which the sleeve and stranded wire can be pushed through the busbar, and on the other hand, welding methods in which the welding takes place through the busbar into the stranded wire and the sleeve, e.g., friction spot welding. Because the welding is carried out starting from the second side, only a small amount of heat is introduced into the individual wires, particularly in an area away from the welding node. The individual wires extend from the flat connection area in the longitudinal direction to the center of the stranded wire. The heat input preferably occurs only in the connection area and penetrates only insignificantly in the longitudinal direction into the individual wires. W / PW 220317WOSeptember 21, 2023. The sleeve reduces the mechanical stress on the weld seam and the individual wires in the weld area under dynamic stress compared to conventional welding methods. By welding from the second side, but especially by using the sleeve, strand breakage under dynamic mechanical stress is largely prevented. The sleeve absorbs the mechanical stresses directly adjacent to the weld / heat-affected zone. According to one embodiment, it is proposed that the busbar have openings, in particular through-openings, in particular bores, in the contact areas. It should be noted that an opening can form a contact area. The openings preferably run parallel to the surface normal of the surface of the busbar in which the contact area is located. The opening preferably has a diameter that corresponds to the diameter of the pressed sleeve.The opening can have a clearance fit, a transition fit, or a press fit with the sleeve. The sleeve is inserted into the opening. The sleeve is inserted into the opening with its connection area, starting from the first side and moving toward the second side. The sleeve is preferably inserted into the opening such that the connection area, after insertion, is flush with the surface of the second side of the busbar or slightly protrudes beyond it (in particular with a tolerance of between 0.2 mm and 2.0 mm). According to one embodiment, it is proposed that the sleeve be inserted through the opening in the busbar such that the sleeve and the individual wires, with their connection areas (after insertion), lie approximately in a plane with the surface of the second side. According to one embodiment, it is proposed that the busbar, the sleeve, and the individual wires be welded together using a laser, starting from the second side.W / PW 220317WOSeptember 21, 2023 When welding the sleeve, the individual wires, and the busbar, the individual wires are particularly welded to one another. The end faces of the individual wires can be welded together using a laser, so that the resulting weld node extends only a few tenths of a millimeter to a few millimeters into the stranded cable. This reduces the thermal stress on the individual wires. In particular, the weld node extends into the stranded cable only by the distance between the first and second sides of the busbar. The sleeve can also be welded to the individual wires. In this case, an inner side surface of the sleeve opening is welded to the individual wires. In particular, the individual wires that are in contact with the outer circumference of the sleeve are welded to the inner surface of the sleeve opening. The sleeve can also be welded to the busbar.In particular, the opening of the busbar is welded to the sleeve. In particular, an outer surface of the sleeve is welded to an inner surface of the opening of the busbar. The welding can be such that a uniform weld node is formed from the individual wires, sleeve, and busbar. A uniform weld node is formed across the individual wires, the sleeve, and the busbar. This uniform weld node seals any gaps between the individual wires, between the individual wires and the sleeve, and between the sleeve and the busbar, preferably completely, so that moisture can no longer penetrate through this weld node in the longitudinal direction along the sleeve and the individual wires into the stranded cable. The weld node is preferably located only at the front end of the individual wires and the sleeve and, in particular, exclusively within the busbar.This means that the weld node spreads along the length of the stranded wire preferably to a maximum extent corresponding to the material thickness of the busbar. The busbar and its material thickness ensure that the individual wires P. W / PW 220317WOSeptember 21, 2023, preferably only in the area of ​​the busbar are exposed to such heat input, which leads to a material influence. The individual wires located in the sleeve outside the busbar on the first side are not or only slightly affected by the welding. The connection between the busbar, sleeve, and stranded wire is thus permanently stable and considerably less sensitive to alternating bending stresses than conventional welds. According to one embodiment, it is proposed that the respective sleeve be placed with its connection area on the contact area of ​​the first side of the busbar. Unlike the previously described embodiments, the busbar has no openings for receiving the sleeves and individual wires. The sleeves and the individual wires are placed with their flat connection area directly on the contact area on the first side.Welding then takes place starting from the second side. Laser welding can be used here, but friction spot welding is preferred. It is proposed that the sleeve, with its connecting area, be placed on the contact area of ​​the first side of the busbar in such a way that the sleeve and the individual wires, with their connecting areas, lie essentially in a plane with the first side. It is preferred that the sleeve, including the individual wires, with its connecting area, be pressed against the contact area of ​​the first side with a contact force. This contact force is preferably greater than the force exerted by a friction spot welding tool on the sleeve and the stranded wire pointing away from the first side. The sleeve, pressed against the first side, including the individual wires, is then welded to the busbar.It is proposed that the busbar, the sleeve and the individual wires be welded together starting from the second side using a friction spot welding process.P. W / PW 220317WOSeptember 21, 2023 Preferably, a friction tool, preferably consisting of at least three parts, is first placed on the second side. The friction tool is preferably placed concentrically to the respective sleeve to be welded on the second side. The friction tool comprises a punch, a sleeve guided in the punch, and a pin arranged in the sleeve. In friction spot welding, the punch and sleeve are placed on the second side. The pin is then placed on the second side in a rotating manner within the sleeve. The rotation of the pin introduces friction energy into the busbar in the area of ​​the pin's contact surface, and the busbar material melts. Subsequently, sufficient friction energy is introduced into the busbar to melt the busbar in the contact area, in particular across its entire material thickness, and in particular up to the first side, the sleeve resting there, and the individual wires.Subsequently, the sleeve resting on the first side and the individual wires in the connection area are also melted. During this melting, the sleeve of the welding tool, which is guided within the die, is preferably moved from the second side toward the first side, so that the molten material from the busbar, individual wires, and sleeve are mixed together, in particular through the busbar. Subsequently, the pin is pulled out of the sleeve of the welding tool while continuously rotating, while the sleeve is moved toward the second side, the busbar. This enables a point connection between the busbar, sleeve, and individual wires without creating a hole.After the molten materials have cooled, the punch and sleeve of the welding tool, as well as the pin of the welding tool, are lifted from the second side, forming a uniform weld node that extends through the busbar into the sleeve and the individual wires. In an alternative friction spot welding process, the punch and sleeve are placed on the second side. The sleeve is then rotated onto the second side. W / PW 220317WOSeptember 21, 2023. By rotating the sleeve, frictional energy is introduced into the busbar in the area of ​​the pin's contact surface, and the busbar material melts. Subsequently, sufficient frictional energy is introduced into the busbar to melt the busbar in the contact area, particularly across its entire material thickness, and particularly up to the first side and the sleeve and individual wires resting there. Subsequently, the sleeve resting on the first side and the individual wires in the connection area are also melted. During this melting, the pin of the welding tool, which is guided inside the sleeve, is preferably moved from the second side toward the first side, so that the molten material of the busbar, individual wires, and sleeve are mixed together, and in particular, mixed together through the busbar.The sleeve is then pulled out of the weld metal while continuously rotating, while the pin is moved toward the second side, the busbar. This enables a spot connection between the busbar, sleeve, and individual wires without leaving a hole. After the molten materials have cooled, the punch and sleeve of the welding tool, as well as the pin of the welding tool, are lifted from the second side, and a uniform weld node is formed that extends through the busbar into the sleeve and the individual wires. It is preferred if the individual wires are welded together. The rotating pin preferably melts all the individual wires at their ends, forming a uniform weld node over preferably all the individual wires. It is also preferred if the individual wires are welded to the sleeve.The rotating pin preferably melts the individual wires and the sleeve at the end faces, forming a uniform weld joint over the individual wires and the sleeve. In particular, the outer circumferential individual wires of the stranded cable are welded to the inner surface of the sleeve. It is also preferred if the sleeve is welded to the busbar. W / PW 220317WOSeptember 21, 2023 The rotating pin preferably melts the sleeve and the busbar, forming a uniform weld node over the sleeve and the busbar. It is preferred if the end face of the sleeve is welded to the busbar on the first side. It is also preferred if the individual wires are welded to the busbar. The rotating pin preferably melts the individual wires and the busbar, forming a uniform weld node over the individual wires and the busbar. It is preferred if the end faces of the individual wires are welded to the busbar on the first side. A uniform, continuous weld node is preferably formed over the busbar, sleeve, and individual wires. This weld node preferably completely closes a gap between the end face of the sleeve and the first side of the busbar.The weld node extends through the busbar into the sleeve and the individual wires resting on the contact surface on the first side. As previously explained, it is preferred that the busbar be formed as a flat part. The busbar can be formed from a sheet or strip. In particular, the busbar can be cut or punched from a sheet or strip. The busbar can be designed such that the contact area(s) are part of a projecting tab. The busbar can have at least one, preferably two opposing tabs or four opposing tabs in pairs. The tabs project outward from one side edge of the flat part of the busbar. The tabs can project on opposite side edges of the busbar. Preferably, one tab can project on each or on more than two side edges of the busbar.The busbar can initially be provided as a flat part and the stranded wire including the sleeve can be firmly connected to the busbar in the manner described above. To achieve certain connection geometries, it can be useful if the longitudinal axes of the stranded wires are angled to the surface normal of the flat partP. W / PW 220317WOSeptember 21, 2023. In particular, it may be expedient for the stranded wires to run in a plane to the busbar that is parallel to the plane of the first and / or second side of the busbar. For this reason, it may be expedient for the respective tabs to be bent around the side edge after welding the busbar in the respective contact areas to the respective sleeve and the individual wires. A bend of more than 45°, in particular between 45 and 135°, in particular 90°, may be expedient. With a bend of 90°, the plane in which the two longitudinal axes of the stranded wires lie is essentially parallel to the plane of the first and / or second side. A further aspect is a connecting arrangement according to claim 11. This connecting arrangement has the advantage that stranded wires are arranged on a busbar without significant structural damage and are thus permanently and stably attached even under dynamic loads.According to one embodiment, it is proposed that the individual wires of the stranded cable be made of aluminum or aluminum alloys. In particular, AL99.5 or Al99.7 as well as soft-annealed aluminum can be advantageous. The material of the busbar can be the same as the material of the stranded cable and / or sleeve and can in particular also be aluminum or an aluminum alloy, or copper or a copper alloy. It is also possible for the material of the busbar to be different from the material of the individual wires. It is also possible for the material of the busbar to be different from the material of the sleeve. As already explained, the end region of the stranded cables is inserted into the sleeve. For this reason, it is proposed that the sleeve have a through-opening running in the longitudinal direction. It is also possible for the P. W / PW 220317WOSeptember 21, 2023 Sleeve has a longitudinally extending blind hole. The individual wires of the stranded cable are inserted into the opening. The sleeve can have a base on one end face, wherein the base can have an opening or taper that has a different cross-section than the opening into which the individual wires are inserted. In particular, a cross-section of the base opening or taper is advantageous in which regions extending radially further outward alternate with regions extending radially less outward. Non-circular outlines of the opening / taper are preferred, whereby, for example, a multiple axial symmetry is possible. In the simplest case, this is a threefold axial symmetry. One possible particularly preferred embodiment provides for the outline of the opening / taper to be approximately similar to an epicycloid.The opening / taper could also have angular outlines, for example, a polygonal outline. Combinations of angular and cycloidal outlines could also be chosen. Such a base design has several advantages. First, the presence of the base ensures that the individual wires are inserted into the sleeve to a defined depth and are not pushed too far through the sleeve's through-opening. The base thus forms a natural stop for the strands. Second, the taper / opening in the base enables radial compression of the sleeve, so that the individual wires and sleeve can be pressed together. As also explained at the beginning, the sleeve can be shaped as a tube. The sleeve can also be formed from a sheet metal. In particular, the sleeve can be formed as a sheet metal folded around the individual wires. The sleeve can be formed in one piece or in multiple pieces. Another aspect is the use according to claim 15.Particularly in motor vehicles, watercraft, aircraft, launch vehicles, spacecraft, and satellites, significant mechanical stresses occur. Especially in P. W / PW 220317WOSeptember 21, 2023 Failure safety is of crucial importance in a launch vehicle or spacecraft. The subject connection is particularly suitable for this application, as it provides a permanently stable connection even under the highest mechanical loads due to the lack of or only minimal impairment of the individual wires during the connection process. The subject matter is explained in more detail below using a drawing showing exemplary embodiments. The drawing shows: Fig. 1a, b a stranded wire according to an exemplary embodiment; Fig. 2a, b sleeves according to exemplary embodiments; Fig. 3a, b placing a sleeve on a stranded wire according to an exemplary embodiment; Fig. 4 cutting a sleeve on a stranded wire according to an exemplary embodiment; Fig. 5a a busbar according to an exemplary embodiment; Fig. 5b a connection between a busbar and a stranded wire according to an exemplary embodiment; Fig.6a shows a busbar according to an embodiment; Fig. 6b shows a connection between a busbar and a stranded wire according to an embodiment; Fig. 7a, b shows a friction spot welding method according to an embodiment;P. W / PW 220317WOSeptember 21, 2023. Fig. 8 shows a busbar with projecting tabs according to one embodiment; Fig. 9 shows a connection arrangement with multiple busbars and multiple stranded wires according to one embodiment. Fig. 1a shows a front end of a cable 2. It can be seen that the cable 2 has insulation 2a. The cable 2 has an electrically conductive core formed as a stranded wire 4. Fig. 1b shows the front end of the cable 2 in a stripped state. In an end region 6, the insulation 2a is removed, and the individual wires of the stranded wire 4 are bare. Such a cable 2 is provided for subsequent processing. It is understood that instead of the cable 2, only the stranded wire 4 without the insulation 2a can be provided. The end region 6 extends from the front end of the stranded wire 4 in the longitudinal direction of the stranded wire 4.A sleeve 8, as shown by way of example in Figures 2a and b, is pushed onto such an end region 6. Figure 2a shows a sleeve 8 which extends in a longitudinal direction 8a. Along the longitudinal direction 8a, the sleeve 8 has an opening 10 formed as a through-opening. The sleeve 8 can have a radial offset so that a first region can be pushed onto the insulation 2a and a second region onto the bare individual wires of the stranded cable 4. The sleeve 8 in Figure 2a is free of a base and the opening 10 is continuous. Figure 2b shows a sleeve 8 with a base 12. The base 12 closes the opening 10 in an end region of the sleeve 8. An opening 14P can be provided in the base 12. W / PW 220317WOSeptember 21, 2023. The opening 14 can have areas that project radially further outwards and areas that project radially less far outwards. The opening 14 enables easy compression in the radial direction of the sleeve 8. Without the opening 14, the base 12 would offer considerable resistance to radial compression, which may not be desired. Fig. 3a shows the sliding of the sleeve 8 along the longitudinal direction 8a onto the cable 2 or the end region 6. After the sleeve 8 has been pushed onto the cable 2, it is preferably compressed radially inwards in the end region 6, as indicated by arrows in Fig. 3b. This presses the sleeve 8 onto the individual wires of the stranded cable 4. The pressed sleeve 8 with the stranded cable 4 is shown in Fig. 4a. Following the pressing, the base 12 of the sleeve 8 is removed.This can be done, for example, by machining by grinding or milling, or non-cutting by cutting, laser cutting, or the like. Fig. 4a shows that the parting plane 15 runs perpendicular to the longitudinal axis 8a. Along the parting plane 15, the front ends of sleeve 8 and stranded wire 4 are exposed, as shown in Fig. 4b. The front ends are preferably plane-parallel to one another. A stranded wire 4 prepared in this way is subsequently used to produce a connecting arrangement. Fig. 5a shows, by way of example, a busbar 18 formed as a flat part. The busbar 18 has a first side 18a and a second side 18b. The sides 18a, 18 are on opposite sides of the busbar 18. The sides 18a, b are preferably parallel to each other on wide surfaces of the busbar 18. The busbar 18 has at least two spaced-apart contact areas 20. The contact areas according to Fig.5a have through-holes through which the sleeve 8 together with the stranded cable 4 is inserted.P. W / PW 220317WOSeptember 21, 2023 The sleeve 8, including the stranded wire 4, is pushed in the insertion direction 22 from the first side 18a to the second side 18b through the through-opening in the contact area 20. After insertion, the end face of the sleeve 8 and the stranded wire 4 is preferably plane-parallel to the side 18b. The sleeve 8, including the stranded wire 4, is fixed in this position relative to the busbar 18. A laser 24 is then used to form a weld node 16 that extends flatly over the busbar 18, the end face of the sleeve 8, and the end face of the stranded wire 4. A uniform weld node 16 is formed that extends flatly over the stranded wire 4, the sleeve 8, and an area of ​​the busbar 18 adjacent to the contact area, and has a depth extension that preferably reaches the material thickness of the busbar 18 in the longitudinal direction 8a.The busbar 18 can have more than two contact areas 20, via each of which a connection to the stranded wire 4 and the sleeve 8 can be formed in the manner shown. Fig. 6a shows a further embodiment in which the busbar 18 has several contact areas 20. In contrast to Figure 5a, however, the contact areas 20 are not through-holes. Rather, it is proposed to press the front ends of the sleeve 8 together with the stranded wire 4 against the busbar 8, starting from the first side 18a. The sleeve 8 and the stranded wire 4 do not penetrate the busbar 18. Friction spot welding then takes place, starting from the second side 18b, so that weld nodes 16 are formed, as shown in Fig. 6b. During friction spot welding, the busbar 18 is melted, starting from the second side 18b in the direction of the first side 18a.This process is continued until the end face of the sleeve 8 and the end face of the stranded wire 4, which rest on the first side, are melted, so that bothP. W / PW 220317WOSeptember 21, 2023 The material of the busbar 18, as well as the material of the sleeve 8 and the material of the stranded wire 4, can be joined to form a single weld node 16. Such a friction spot welding is shown schematically in Figures 7a and b. In Figure 7a, it can be seen that the sleeve 8, including the stranded wire 4, is pressed with its front ends against the first side 18. A friction spot welding tool 26 is then placed on the second side 18b. A stamp 26a is placed on the second side 18b in the contact area 20. A sleeve 26b and a bolt / pin 26c are movably arranged within the stamp 26a. For friction spot welding, the bolt 26c is rotated in the direction of rotation 28 and pressed against the material of the busbar 18, starting from the second side 18b. The rotation of the bolt 26c initially melts the material of the busbars 18.The bolt is driven further toward the stranded wire 4 into the material of the busbar 18 until it also at least partially melts the material of the stranded wire 43 and sleeve 8. The sleeve 26b is moved away from the busbar 18 in the opposite direction, creating a vacuum so that the molten material is thoroughly mixed. Finally, as shown in Fig. 7b, the bolt 26c is moved away from the first side 18b, transporting the melted material to the second side. At the same time, the sleeve 26b is moved toward the stranded wire 4. This counter-directional movement thoroughly mixes the molten material, creating a uniform weld node. W / PW 220317WOSeptember 21, 2023. Preferably, the bolt 26b is raised so far that its end face remains in the plane of the second side 18b, so that after lifting, the weld node 16 is plane-parallel to the second plane 18b. Fig. 8 shows a busbar 18 having tabs 28 on two longitudinal edges 18'. The tabs 28 project outward from the longitudinal edge 18'. The tabs 28 can be bent around the longitudinal edge 18' along the longitudinal edge 18', so that a U- or Z-shaped profile of the busbar 18 is formed in section. The contact regions 20 are provided on the tabs 28. It is preferred that the stranded wire 4, including the sleeve 8, be arranged on the contact regions 20 in the manner described above, and then the tabs 28 are bent around the longitudinal edges 18'. Fig.Figure 9 shows a configured connection arrangement in which, starting from a central busbar 18, three cables 2 are arranged on opposing lugs 28 and run in opposite directions. The cables 2 are connected at their respective other distal ends to further lugs 28 on busbars 18 in the manner described. Using the method shown, it is possible to provide permanently stable connections between stranded cables and busbars. W / PW 220317WO September 21, 2023

Claims

September 21, 2023 Patent Claims 1. A method for connecting at least two stranded wires to a busbar, in which - the at least two stranded wires are provided, each stranded wire having an end region in which the individual wires of the stranded wire are free of insulation, - a sleeve is pushed onto the respective end region, - the respective sleeve is pressed onto the individual wires, - the respective connecting regions are placed on the busbar in two spaced-apart contact regions, the contact regions lying on a common first side of the busbar, and - starting from a second side of the busbar opposite the first side, the sleeve, the individual wires, and the busbar are welded together in a respective contact region. 2.Method according to claim 1, characterized in that - the busbar has openings in the two contact areas, in particular through-openings, in particular bores, into which the respective sleeve is inserted with its connection area, starting from the first side towards the second side.

3. Method according to claim 2, characterized in that - the sleeve is inserted through the opening into the busbar in such a way that the sleeve and the individual wires with their connection area lie approximately in the same plane as the second side. - 2 -4. Method according to one of the preceding claims, characterized in that - the busbar, the sleeve, and the individual wires are welded together starting from the second side by means of a laser, in particular that the individual wires are welded to the sleeve, in particular to an inner surface of the sleeve, and the sleeve is welded to the busbar, in particular to an inner surface of the opening.

5. Method according to claim 1, characterized in that - the respective sleeve is placed with its connecting region on the first side of the busbar.

6. Method according to claim 5, characterized in that - the sleeve is placed with its connecting region on the first side of the busbar in such a way that the sleeve and the individual wires with their connecting region lie approximately in one plane with the first side.7.Method according to claim 5 or 6, characterized in that the busbar, the sleeve and the individual wires are welded together starting from the second side by means of a friction spot welding process, in particular that the individual wires are welded to the sleeve, in particular to an inner surface of the sleeve, and the sleeve is welded to the busbar.

8. Method according to one of the preceding claims, characterized in thatP. W / PW 220317WO September 21, 2023 - 3 -- that the busbar is formed as a flat part, wherein the contact regions are part of a tab of the flat part projecting from a longitudinal edge.

9. Method according to claim 8, characterized in that - after welding the busbar to the sleeve and the individual wires, the tab is bent around the longitudinal edge, in particular bent by more than 45°.

10. Method according to one of the preceding claims, characterized in that - the respective sleeve is cut to length on the end face such that the individual wires and the sleeve essentially form a planar connection region on the end face of the sleeve.

11. Method according to claim 8 or 9, characterized in that - a tab is arranged on each of two opposite longitudinal edges and at least two stranded wires are welded to a respective tab.12.Connection arrangement between at least two stranded wires and a busbar, in particular produced according to a method according to one of the preceding claims, in which - the at least two stranded wires each have an end region in which the individual wires of the stranded wire are free of insulation, - a sleeve is pushed onto the respective end region, - the respective sleeve is pressed onto the individual wires, - the respective connection regions are placed on a busbar in two spaced-apart contact regions, the contact regions lying on a common first side of the busbar andP. W / PW 220317WO September 21, 2023 - 4 -- starting from a second side of the busbar opposite the first side, the sleeve, the individual wires, and the busbar are welded together in a respective contact area.

13. Connecting arrangement according to claim 11, characterized in that - the individual wires of the stranded wire are made of aluminum or aluminum alloys and / or - the busbar is made of aluminum or aluminum alloys. nd / oder- that the sleeve is made of aluminum or aluminum alloys.

14. Connection arrangement according to one of claims 11 to 13, characterized in that the sleeve has a longitudinally extending through-opening or a longitudinally extending blind hole into which the individual wires of the stranded wire are inserted.

15. Connection arrangement according to one of claims 11 to 14, characterized in that the sleeve is formed from a tube or a sheet metal.

16. Connection arrangement according to one of claims 11 to 14, characterized in that the at least two stranded wires are each welded to a busbar by their distal ends.

17. Use of a connection arrangement according to one of claims 11 to 15 in a motor vehicle, watercraft, aircraft, or a launch vehicle, a spacecraft, or a satellite. W / PW 220317WO September 21, 2023

Images