Method for connection arrangement of at least two stranded conductors, connection arrangement and use

Abstract

The invention relates to a method for connecting at least two stranded conductors to a busbar, in which: the at least two stranded conductors are provided, each stranded conductor having an end region, the individual strands of the stranded conductors having no insulating layer there; the sleeves are pushed to all the end areas, and all the sleeves are pressed to the single-strand wires; the connection regions are arranged in two spaced-apart contact regions on the busbar, the contact regions being located on a common busbar first side; and the sleeve, the single-strand wire and the busbar are welded together in each contact area from a second side surface, opposite to the first side surface, of the busbar.

Description

Technical Field

[0001] The invention relates to a method for connecting at least two stranded conductors to a busbar, a corresponding connection between two stranded conductors and a busbar, and the use of such a connection arrangement. Background Art

[0002] The connection of several wires to a potential busbar in a confined space, especially with a material-locked connection, is challenging both in terms of connection technology and in terms of connection quality and durability. In particular, when connecting aluminum stranded conductors to aluminum or copper metal busbars, known connection methods, such as laser welding, weaken the individual wire strands due to the temperature input by the laser in the vicinity of the welding zone, especially in the longitudinal direction of the individual wire strands at a certain distance from the actual welding zone. This weakening of the individual wire strands during the connection of the conductors to the busbar can have a negative impact on the durability of the connection, especially in a dynamic environment. Since the individual wire strands are already damaged from the outset, alternating bending loads can lead to more stranded conductor breakages.

[0003] The wires connected to the busbars are usually several centimeters to several meters long. Such wires cannot be contacted with the busbar using rotary friction welding. It is not possible to rotate such long wires during the welding process. On the other hand, as soon as a second wire is arranged on the busbar, the busbar cannot be rotated around this second wire. This rules out rotary friction welding as a connection technology.

[0004] Ultrasonic welding can also present problems if multiple connections are to be made on a busbar using ultrasonic welding. Existing ultrasonic welds can be negatively affected, damaged or destroyed by the incoming ultrasonic vibrations during the subsequent welding process. Therefore, if multiple stranded conductors on a busbar need to be contacted and the weld points are close to each other, these stranded conductors cannot be reliably connected using ultrasonic welding. Summary of the invention

[0005] It is therefore an object of the present invention to provide a welding method which enables a plurality of stranded conductors to be connected to a common busbar in a durable and stable manner in a material-locking manner.

[0006] This object is achieved by the method according to claim 1 .

[0007] In particular, it is recommended to provide at least two twisted conductors. A twisted conductor is a conductor with a plurality of individual wires, without individual insulation between the individual wires. The individual wires can be interwoven, twisted and / or wound together. The individual wires are made of metal, in particular of transition metals. Aluminum or copper and aluminum or copper alloys are particularly suitable materials for the individual wires. The individual wires of the twisted conductor can be coated with a common insulation layer. Combinations of the above materials can also be used.

[0008] Each stranded conductor has two distal ends. One end may have an end region in which the individual wires of the stranded conductor are free of insulation. To avoid misunderstandings, it should be explicitly pointed out that the stranded conductor may also be completely free of insulation. The stranded conductor is preferably part of a cable, wherein the cable consists at least of the stranded conductors and an insulation layer. There is no insulation layer in the end region, in particular the insulation layer in this region has been removed. The end region may extend from the front end of the stranded conductor to the center of the stranded conductor, in particular longitudinally extending between 0.5 cm and 5 cm or longer. The insulating material may in particular be silicone, PVC, VPE, PTFE, PES, PE or a similar material.

[0009] In particular, it is proposed to push the sleeve onto the end region of the stranded conductor. The sleeve can be pushed onto only one end region of the stranded conductor or onto both distal end regions. Each stranded conductor that is connected to the actual contact of the busbar has a sleeve pushed onto it at least at one end region. The sleeve is preferably made of a metallic material, in particular the same material as the stranded conductor and / or the busbar. The sleeve can also be made of a different material than the stranded conductor and / or the busbar. The sleeve can be made of aluminum, copper, an aluminum alloy or a copper alloy.

[0010] In this case, the sleeve can be pushed from the front end of the stranded conductor onto the individual wires of the stranded conductor. In this case, the sleeve is preferably pushed in the longitudinal direction of the stranded conductor to the end region. As described below, the sleeve can be designed as a one-piece component or as a multi-part component. The sleeve has an opening extending in the longitudinal direction, into which the individual wires of the stranded conductor are inserted. The sleeve can also be made of a metal strip, which is placed circumferentially around the individual wires of the stranded conductor in the end region and, if necessary, welded.

[0011] After the sleeves have been pushed onto the respective end regions, it is advisable to press the sleeves onto the individual wires. For this purpose, the sleeves are radially pressed (pressed). By pressing the opening of the sleeve radially inwards, the sleeves are connected to the individual wires in a force-locking and form-locking manner. When the sleeves are pressed onto the individual wires, the individual wires are compressed. The degree of compression of the individual wires is preferably more than 90%, more preferably more than 95%, in particular more than 98%. The degree of compression is preferably determined as a function of the ratio of the metal cross-sectional area to the cross-sectional area of ​​the entrained air, preferably in a cross section perpendicular to the longitudinal axis of the stranded conductor.

[0012] The cross-sectional area of ​​a single strand is 4* 金属线 2 / π. The cross-sectional area of ​​all N single-strand wires is N*4*D 金属线 2 / π. The cross-sectional area of ​​the casing is determined by the outer diameter of the casing (D 外 ) cross-sectional area and the inner diameter of the casing (D 内 ) cross-sectional area The difference is obtained, that is The total cross-sectional area of ​​the stranded conductors, the single wires and the sleeve without entrained air is This is the cross-sectional area of ​​the metal portion of the casing including the individual wires. The cross-sectional area of ​​the compressed casing (including the wires and any residual entrained air) is (4* 压紧 2 / π)

[0013] The degree of compression is given by the quotient of the total cross-sectional area and the cross-sectional area of ​​the compressed casing, i.e.

[0014]

[0015] Compression in short means:

[0016]

[0017] Assuming that the sleeve and the wire are not axially stretched during the compression process, the compression degree of the fully compressed sleeve without entrained air is 1 (100%). It is recommended that the compression degree is between 90% and 100%, preferably between 95% and 100%, and especially between 98% and 100%.

[0018] However, it is conceivable and advisable to at least axially stretch the sleeve during the pressing process. This would result in the values ​​of the pressed sleeve is smaller than the value of the uncompressed sleeve. This in turn means that the cross-sectional area of ​​the compressed sleeve is smaller than the total cross-sectional area in the uncompressed state. This results in a compression greater than 100%. It is recommended to achieve a compression greater than 100%, in particular between 100% and 110%, more preferably between 100% and 105%, and in particular between 100% and 102%, by axially stretching the sleeve during the compression process.

[0019] After the sleeve is pressed onto the single-stranded wire, each sleeve is preferably cut to a fixed length together with the single-stranded wire on the end face, so that the single-stranded wire and the sleeve basically form a planar connection area on the end face of the sleeve. The connection area is preferably located on a plane perpendicular to the longitudinal axis of the stranded conductor. The connection area is preferably a plane formed by the end face of the sleeve that has been cut to a fixed length and the end face of the single-stranded wire of the stranded conductor that has been cut to a fixed length. When cutting to a fixed length, all the single-stranded wires of the stranded conductor are preferably cut to a fixed length. In this way, all the single-stranded wires that may be longitudinally retracted from the end face are cut to a fixed length, so that all the single-stranded wires are attached to the end face of the connection area and form a common plane with the end face of the sleeve.

[0020] The cutting to length is preferably carried out by means of laser cutting. However, the cutting to length can also be carried out by milling or sawing. If necessary, the end faces of the single strands and the sleeve can also be cut to length by grinding to form the connection area. The cutting to length can also be carried out in combination with the above methods.

[0021] The sleeve and the single-stranded conductor arranged in the sleeve together with its connection area are then placed on the bus. As mentioned at the beginning, at least two twisted conductors and two sleeves are provided. The description of any one sleeve (including the single-stranded conductor) naturally applies to all at least two twisted conductors with sleeves. It should be noted that the individual method steps in this document only partially describe the twisted conductors and / or sleeves. It should also be noted that these method steps are preferably applicable to all sleeves connected to the bus, but at least to two sleeves and twisted conductors connected to the bus. In this regard, the word "individual" is sometimes used to express the fact that not only one, but a plurality of sleeves and twisted conductors and their connection areas are connected to the spaced-apart contact areas of the bus.

[0022] In particular, it is proposed to place the individual connection regions in contact areas on the busbar which are spaced apart from one another.

[0023] The busbar has an area for connecting the twisted conductors. In this area, at least two contact areas are arranged with a space between them, which are used to accommodate the connection areas of each twisted conductor. The connection areas are placed in two spaced-apart contact areas. The number of contact areas corresponds to the number of connection areas, i.e. two twisted conductors have two contact areas, and N twisted conductors have N contact areas.

[0024] It is recommended to arrange the contact areas on one side of a common busbar. The connection areas are placed in the contact area of ​​the busbar on a common side. The busbar is preferably designed as a planar component and has two oppositely located wide surfaces. The wide surfaces preferably extend parallel to each other. The contact areas are preferably located on a common wide surface. The busbar is preferably made of a metallic material, in particular the same material as the stranded conductors and / or the sleeves. The busbar can also be made of a different material than the stranded conductors and / or the sleeves. The busbar can be made of aluminum, copper, an aluminum alloy or a copper alloy. The connection areas are placed in the contact areas.

[0025] The sleeve and the individual wires are then welded to the busbar. At the same time, it is particularly recommended to weld the sleeve, the individual wires and the busbar together in each contact area starting from the second side of the busbar opposite to the first side. That is, the welding starts from the second side opposite to the first side. As described below, various welding methods are suitable for this, on the one hand, welding methods in which the sleeve together with the stranded wire is pushed through the busbar; on the other hand, welding methods in which the stranded wire and the sleeve are inserted through the busbar, such as friction spot welding.

[0026] By welding from the second side, only a small amount of heat is input into the individual wires, especially in the area away from the weld. The individual wires extend longitudinally from the flat connection area to the center of the stranded conductor. The heat input preferably only takes place in the connection area and penetrates only slightly into the individual wires in the longitudinal direction.

[0027] Compared to conventional welding methods, the sleeve reduces the mechanical load on the weld and the individual strands in the weld area under dynamic stress. By starting the welding from the second side and especially using the sleeve, the stranded conductors can be largely prevented from breaking under dynamic, mechanical loads. The sleeve absorbs the mechanical loads directly in the vicinity of the weld / heat-affected zone.

[0028] According to one embodiment, it is recommended that the busbar has an opening, in particular a through hole, in particular a drilled hole, in the contact area. It should be noted that the opening can constitute the contact area. The opening is preferably parallel to the surface normal of the busbar surface where the contact area is located. The diameter of the opening is preferably consistent with the diameter of the compressed sleeve. The opening and the sleeve can be a clearance fit, a transition fit or a press fit. The sleeve is inserted into the opening. Therein, the sleeve and its connection area are inserted into the opening from the first side to the second side. The sleeve is preferably inserted into the opening in such a way that after insertion, the connection area is flush with or slightly protrudes from the surface of the second side of the busbar (in particular, the tolerance is between 0.2mm and 2.0mm). According to one embodiment, it is recommended to insert the sleeve into the busbar through the opening so that the connection area of ​​the sleeve and the single strand (after insertion) is approximately in the same plane as the surface of the second side.

[0029] According to one embodiment, it is proposed to weld the busbar, the sleeve and the individual wires together by laser starting from the second side.

[0030] When welding the sleeve, the individual wires and the busbar, the individual wires are welded together. The end faces of the individual wires can be welded together by means of a laser so that the formed weld only extends from 1 / 10 mm to several mm into the stranded conductor. This can reduce the temperature load on the individual wires. In particular, the weld only extends into the stranded conductor according to the distance between the first side and the second side of the busbar.

[0031] The sleeve can also be welded with the stranded wire. Here, in particular, the inner surface of the sleeve opening can be welded with the stranded wire. In particular, the stranded wire that abuts against the sleeve on the outer circumference can be welded with the inner side of the sleeve opening.

[0032] The sleeve can also be welded to the busbar. In particular, the opening of the busbar can be welded to the sleeve. In particular, the outer side of the sleeve can be welded to the inner side of the opening of the busbar. During welding, the individual wires, the sleeve and the busbar can form a unified weld. A unified weld is formed on the individual wires, the sleeve and the busbar. This unified weld can seal (preferably completely seal) any gaps between the individual wires, between the individual wires and the sleeve, and between the sleeve and the busbar, so that moisture can no longer pass through this weld and penetrate into the twisted conductor along the sleeve and the individual wires in the longitudinal direction.

[0033] The weld is preferably located only at the front end of the individual wires and the sleeve, in particular only in the busbar. This means that the weld preferably extends in the longitudinal direction of the stranded conductor and at most corresponds to the material thickness of the busbar. The busbar and its material thickness ensure that the individual wires are preferably exposed to a heat input that affects the material only in the region of the busbar. The individual wires in the sleeve on the first side outside the busbar are not affected by the welding, or are affected only minimally. As a result, the connection between the busbar, the sleeve and the stranded conductor is durable and stable and is much less sensitive to alternating bending loads than conventional welding.

[0034] According to one embodiment, it is proposed to arrange the sleeves and their connection areas in the contact area of ​​the first side of the busbar. Unlike the previous embodiment, the busbar has no openings for accommodating the sleeves and the single strands. The planar connection area of ​​the sleeves and the single strands is directly located on the contact area of ​​the first side.

[0035] Welding then begins from the second side. Laser welding can be used here, but friction spot welding is preferably used. It is recommended to place the sleeve with its connection area on the contact area of ​​the first side of the busbar so that the connection area of ​​the sleeve and the individual wires is essentially in the same plane as the first side. The sleeve is preferably pressed together with the individual wires with its connection area against the contact area of ​​the first side by a pressing force. The pressing force is preferably greater than the force exerted by the friction spot welding tool on the sleeve and the stranded wire away from the first side.

[0036] Then the sleeve pressed on the first side is welded with the single strand and the busbar. Here, it is suggested that busbar, sleeve and single strand are welded together by friction spot welding starting from the second side.

[0037] Preferably, a reaming tool, preferably at least three-stage, is first arranged on the second side. Wherein, the reaming tool is preferably arranged coaxially with the corresponding sleeve to be welded on the second side. The reaming tool includes a punch, a sleeve guided in the punch, and a pin arranged in the sleeve. During friction spot welding, the punch and the sleeve are located on the second side. The pin in the sleeve is then arranged in a rotating manner on the second side. Through the rotation of the pin, friction energy is introduced into the busbar in the pin contact surface area, so that the material of the busbar melts. In this way, in the following process, sufficient friction energy is introduced into the busbar, so that the busbar melts in the contact area, especially in its entire material thickness, especially until the first side and the sleeve and the single strands abutting there. Then, the sleeve and the single strands abutting on the first side in the connection area also melt. During the melting process, the sleeve of the welding tool is preferably moved from the second side to the first side under the guidance of the inside of the punch, so that the molten materials of the busbar, the single strands and the sleeve are mixed with each other, especially via the busbar.

[0038] Then, the pin is pulled out of the sleeve of the welding tool by continuous rotation, while the sleeve moves toward the second side of the busbar. In this way, a point connection can be achieved between the busbar, the sleeve and the single strand without drilling. After the molten material cools, the punch and sleeve of the welding tool and the pin of the welding tool are removed from the second side, and a unified weld is formed, which extends through the busbar into the sleeve and the single strand.

[0039] In another friction spot welding method, the punch and the sleeve are located on the second side. The sleeve is then arranged in a rotating manner on the second side. By rotating the sleeve, friction energy is introduced into the busbar in the area of ​​the pin contact surface, so that the material of the busbar melts. In the following process, sufficient friction energy is introduced into the busbar so that the busbar melts in the contact area, especially over its entire material thickness, especially up to the first side and the sleeve and the single strands abutting there. Then, the sleeve and the single strands abutting against the first side in the connection area also melt. During the melting process, the pin of the welding tool is guided inside the sleeve, preferably moved from the second side to the first side, so that the molten materials of the busbar, the single strands and the sleeve are mixed with each other, especially mixed with each other via the busbar.

[0040] The sleeve is then pulled out of the weld metal while continuously rotating, while the pin is moved toward the second side of the busbar. This allows point connections between the busbar, sleeve, and individual wires without drilling. After the molten material cools, the punch and sleeve of the welding tool and the pin of the welding tool are removed from the second side, forming a uniform weld that extends through the busbar into the sleeve and individual wires.

[0041] The individual wires are preferably welded to each other. The rotating pin preferably melts the individual wires on all end faces and preferably forms a uniform weld on all individual wires. In addition, the individual wires are preferably welded to the sleeve. The rotating pin preferably melts the sleeve and the individual wires on the end face and preferably forms a uniform weld on the individual wires and the sleeve. In particular, the outer circumferential individual wires of the stranded conductor are welded to the inner side of the sleeve. In addition, the sleeve is preferably welded to the busbar. The rotating pin preferably melts the sleeve and the busbar and preferably forms a uniform weld on the sleeve and the busbar. At the same time, the end face of the sleeve is preferably welded to the busbar on the first side. In addition, the individual wires are preferably welded to the busbar. The rotating pin preferably melts the individual wires and the busbar and preferably forms a uniform weld on the individual wires and the busbar. At the same time, the end faces of the individual wires are preferably welded to the busbar on the first side. Preferably, a uniform, continuous weld is formed on the busbar, the sleeve and the individual wires. The weld preferably completely closes the gap between the sleeve end face and the first side of the busbar. The weld extends through the busbar to the sleeve and the individual wires resting on the contact surface of the first side.

[0042] As mentioned above, the busbar is preferably formed as a planar component. The busbar can be formed from a metal sheet or a metal strip. In particular, the busbar can be cut or stamped from a metal sheet or a metal strip. The busbar can be designed accordingly so that the contact area becomes part of a protruding tab. The busbar can have at least one, preferably two tabs that are opposite to each other, or four tabs that are opposite to each other in pairs. The tab protrudes outward from one side of the planar component of the busbar. The tab can extend from the sides of the busbar that are opposite to each other. The tab can preferably also extend from each or more sides of the busbar. The busbar can initially be provided as a planar component, and the stranded conductors and the sleeves can be connected to the busbar in a material-locked manner as described above.

[0043] Advantageously, in order to achieve a defined connection geometry, the longitudinal axis of the stranded conductor is at an angle to the surface normal of the planar component. It is particularly advantageous if the stranded conductor extends in a plane parallel to the plane of the first and / or second side surface of the busbar. For the reasons mentioned above, it may also be advantageous to bend the tabs around the sides after the busbar is welded together with the sleeves and the individual conductors in the contact areas. Advantageously, the degree of curvature is greater than 45°, in particular between 45° and 135°, in particular 90°.

[0044] When the curvature is 90°, the planes in which the two longitudinal axes of the twisted conductors lie are substantially parallel to the planes of the first and / or second side surfaces.

[0045] Another aspect relates to a connection arrangement according to claim 11. This connection arrangement has the advantage that the arrangement of the litz wires on the busbar does not cause significant damage to the structure and can be permanently fixed even under dynamic loads.

[0046] According to one embodiment, it is proposed that the individual wires of the stranded conductor are made of aluminum or an aluminum alloy. AL99.5 or Al99.7 as well as soft annealed aluminum may be particularly advantageous.

[0047] The material of the busbar can be the same as the material of the stranded conductor and / or the sleeve, in particular aluminum or an aluminum alloy, or copper or a copper alloy. The material of the busbar may also be different from the material of the single strand. The material of the busbar may also be different from the material of the sleeve.

[0048] As mentioned above, the end region of the stranded conductor is inserted into the sleeve. For this reason, it is suggested that the sleeve has a through hole extending in the longitudinal direction. The sleeve may also have a blind hole extending in the longitudinal direction. The single strands of the stranded conductor are inserted into the opening. One end face of the sleeve may have a bottom, wherein the bottom may have an opening or a tapered portion, the cross section of which is different from the opening in which the single strand is inserted. In particular, the cross section of the bottom opening or tapered portion is advantageous, wherein the area extending radially outward more alternates with the area extending radially outward less. The profile of the opening / tapered portion is preferably non-circular, for example, it may be multi-axis symmetric. In the simplest case, this is triple axis symmetry. A possible particularly preferred embodiment provides that the profile shape of the opening / tapered portion is similar to an epicycloid. The opening / tapered portion may also have a polygonal profile, for example a polygonal profile. A combination of polygonal and cycloid profiles may also be selected.

[0049] This design of the bottom has several advantages. First, the presence of the bottom ensures that the single strands are inserted into the sleeve to the specified depth and not too far through the sleeve opening. The bottom thus acts as a natural stop for the stranded conductors. Additionally, the taper / opening in the bottom compresses the sleeve radially, thereby pressing the single strands and sleeve together.

[0050] As mentioned at the outset, the sleeve can be configured as a tube. The sleeve can also be formed from a metal sheet. In particular, the sleeve can be a metal sheet that is crimped around a single strand. The sleeve can be formed in one piece or in separate pieces.

[0051] A further aspect relates to the use according to claim 15. In particular in motor vehicles, water vehicles, aircraft, launch vehicles or spacecraft and satellites. Considerable mechanical loads occur. Especially in launch vehicles or spacecraft, reliability is particularly important. For this purpose of use, the connection method according to the invention is particularly suitable because the individual wires are not damaged or only slightly damaged during the connection process, so that this connection method can provide a durable and stable connection even under the greatest mechanical loads. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] The present invention will be explained in more detail below with reference to the accompanying drawings which illustrate embodiments.

[0053] Figure 1a , b a twisted conductor according to one embodiment;

[0054] Figure 2a , b a sleeve according to an embodiment;

[0055] Figure 3a b. According to one embodiment, a sleeve is placed on the twisted conductor;

[0056] FIG4 cuts the sleeve to length on the twisted conductor according to one embodiment;

[0057] Figure 5a A busbar according to one embodiment;

[0058] Figure 5b A connection between a busbar and a stranded conductor according to one embodiment;

[0059] Figure 6a A busbar according to one embodiment;

[0060] Figure 6b A connection between a busbar and a stranded conductor according to one embodiment;

[0061] Figure 7a , b. A friction spot welding method according to an embodiment;

[0062] Figure 8 A busbar with protruding tabs according to one embodiment;

[0063] Fig. 9 According to an embodiment of the present invention, a connection arrangement between a plurality of busbars and a plurality of twisted conductors,

[0064] Figure 1a The front end of the cable 2 is shown. It can be seen that the cable 2 has an insulating layer 2a. The cable 2 has an electrically conductive core which is formed as a stranded conductor 4.

[0065] Figure 1bThe front end of the cable 2 is shown in a stripped state. In the end region 6, the insulation layer 2a has been removed and the individual wires of the stranded conductor 4 are exposed. DETAILED DESCRIPTION

[0066] Such a cable 2 can be used for subsequent processing. Of course, it is also possible to provide only a stranded conductor 4 without an insulating layer 2a instead of the cable 2. The end region 6 extends from the front end of the stranded conductor 4 along the longitudinal direction of the stranded conductor 4.

[0067] like Figure 2a In the example shown in FIG. 2b , the sleeve 8 is pushed onto the end region 6 .

[0068] Figure 2a The sleeve 8 is shown extending in the longitudinal direction 8a. Along the longitudinal direction 8a, the sleeve 8 has an opening 10 formed as a through hole. The sleeve 8 can have a radial offset so that a first part is pushed onto the insulating layer 2a and a second part is pushed onto the bare single wires of the stranded conductor 4. Figure 2a The sleeve 8 does not contain a bottom, and the opening 10 is a through hole.

[0069] Figure 2b A sleeve 8 with a bottom 12 is shown. The bottom 12 closes the opening 10 in the end region of the sleeve 8. An opening 14 can be provided in the bottom 12. The opening 14 can have a region protruding more radially outwards and a region protruding less radially outwards. The opening 14 allows easy compression in the radial direction of the sleeve 8. Without the opening 14, the bottom 12 would present considerable resistance to radial compression, which is also undesirable.

[0070] Figure 3a It is shown that the sleeve 8 is pushed onto the cable 2 or the end region 6 in the longitudinal direction 8 a.

[0071] like Figure 3b As shown by the middle arrow, after the sleeve 8 is pushed onto the cable 2, it is preferably pressed radially inwards in the end area 6. In this way, the sleeve 8 is pressed against the individual wires of the stranded conductor 4.

[0072] The compressed sleeve 8 with the stranded conductor 4 is as follows Figure 4a After pressing, the bottom 12 of the sleeve 8 is removed. This can be achieved, for example, by cutting processes such as grinding or milling, or by chipless processes such as cutting, laser cutting, or the like. Figure 4a As shown, the separation plane 15 is perpendicular to the longitudinal axis 8a. Figure 4b As shown, the front ends of the sleeve 8 and the stranded conductor 4 are exposed along the separation plane 15. The front ends are preferably parallel to each other.

[0073] The connecting arrangement is then produced using the litz-wire conductors 4 prepared in this way. Figure 5aThe busbar 18 is shown as an example, which is formed as a flat component. The busbar 18 has a first side 18a and a second side 18b. The two side surfaces 18a, 18b are located on opposite sides of the busbar 18. The two side surfaces 18a, b are preferably parallel to each other on the wide surface of the busbar 18.

[0074] The busbar 18 has at least two spaced-apart contact areas 20. Figure 5a The contact area has a through hole, through which the sleeve 8 and the stranded conductor 4 can be inserted. The sleeve 8 and the stranded conductor 4 are pushed from the first side 18a to the second side 18b along the insertion direction 22 and pass through the through hole of the contact area 20.

[0075] After insertion, the end faces of the sleeve 8 and the stranded conductor 4 are preferably parallel to the side surface 18b. The sleeve 8 together with the stranded conductor 4 is fixed in this position relative to the busbar 18. Subsequently, a weld 16 is formed by means of a laser 24, which extends flat over the busbar 18, the end face of the sleeve 8 and the end face of the stranded conductor 4. A uniform weld 16 is formed, which extends flat over the stranded conductor 4, the sleeve 8 and the area of ​​the busbar 18 adjacent to the contact area, and whose depth preferably reaches the material thickness of the busbar 18 in the longitudinal direction 8a.

[0076] The busbar 18 may have more than two contact areas 20 , and each contact area 20 may be connected to the stranded conductor 4 and the sleeve 8 in the manner shown in the figure.

[0077] Figure 6a Another embodiment is shown in which the busbar 18 has a plurality of contact areas 20. Figure 5a On the contrary, these contact areas 20 are not through holes. Instead, it is recommended to press the front end of the sleeve 8 together with the stranded conductor 4 from the first side 18a against the busbar 8. The sleeve 8 and the stranded conductor 4 do not pass through the busbar 18. Then, friction spot welding is performed starting from the second side 18b, so that the weld 16 is formed, as shown in FIG. Figure 6b shown.

[0078] During the friction spot welding process, the busbar 18 melts from the second side 18b toward the first side 18a. This process continues until the end face of the sleeve 8 and the end face of the stranded conductor 4 located on the first side are also melted, so that the material of the busbar 18, the material of the sleeve 8 and the material of the stranded conductor 4 can be connected together to form a weld 16.

[0079] The schematic diagram of this friction spot welding is as follows Figure 7a and b. Figure 7a As can be seen in the figure, the front end of the sleeve 8 and the stranded conductor 4 is pressed against the first side 18a. Then the friction spot welding tool 26 is placed on the second side 18b. Here, the punch 26a is placed on the second side 18b in the contact area 20.

[0080] The sleeve 26b and the pin / pin 26c are arranged in a movable manner in the punch 26a. During friction spot welding, the pin 26c is rotated in the rotation direction 28 and is pressed against the material of the busbar 18 starting from the second side 18b under a contact pressure.

[0081] The rotation of the pin 26c first melts the material of the busbar 18. The pin is driven further into the material of the busbar 18 in the direction of the litz-conductor 4 until the material of the litz-conductor 4 and of the sleeve 8 is also at least partially melted.

[0082] The sleeve 26b is moved away from the busbar 18 in the opposite direction while negative pressure is created, thereby causing the molten materials to mix.

[0083] Finally, if Figure 7b As shown, the pin 26c is moved away from the first side 18b, wherein it transports the molten material to the second side. At the same time, the sleeve 26b is moved in the direction of the stranded conductor 4. The molten materials are mixed by this counter-rotating movement and a uniform weld is formed.

[0084] Preferably, the pin 26b is lifted up so that its end surface is kept in the plane of the second side surface 18b, so that the weld 16 is parallel to the plane of the second side surface 18b after lifting up.

[0085] Figure 8 A busbar 18 is shown, which has tabs 28 on its two longitudinal edges 18'. The tabs 28 extend outward from the longitudinal edges 18'. The tabs 28 can be bent along the longitudinal edges 18' around the longitudinal edges 18', so that a U-shaped or Z-shaped profile of the busbar 18 is formed in cross section. The contact area 20 is located on the tabs 28. Preferably, the stranded conductor 4 and the sleeve 8 are arranged together in the contact area 20 in the above-described manner, and then the tabs 28 are bent around the longitudinal edges 18'.

[0086] Fig. 9 A connection arrangement is shown in which, starting from the middle busbar 18, three cables 2 are arranged on lugs 28 located opposite to each other and extend in opposite directions. The cables 2 are connected to another lug 28 on the busbar 18 in the aforementioned manner at their respective other distal ends.

[0087] The method described makes it possible to provide a durable and stable connection between the stranded conductor and the busbar.

Claims

1. A method for connecting at least two twisted conductors to a busbar, wherein - at least two twisted conductors are provided, wherein Each litz conductor has an end region where the individual wires of the litz conductor are free of insulation. - Push the sleeves onto the respective end regions, - Press the sleeves onto the individual wires, the connection regions are arranged on the busbar in two spaced-apart contact areas, wherein the contact areas are located on a common first side of the busbar, and - Starting from a second side of the busbar opposite to the first side, the sleeve, the individual conductors and the busbar are welded together in each contact area.

2. The method according to claim 1, It is characterized in that The two contact areas of the busbar have openings, in particular through-holes, in particular bores, into which the respective sleeves are inserted, the connection region of the sleeves extending from the first side surface to the second side surface.

3. The method according to claim 2, It is characterized in that - Insert the sleeve through the opening into the busbar so that the connection area between the sleeve and the individual wires and the second side surface are approximately in one plane.

4. The method according to any one of the preceding claims, It is characterized in that The busbar, the sleeve and the individual wires are welded to each other by laser starting from the second side, in particular the individual wires are welded to the sleeve, in particular the inner side of the sleeve, and the sleeve is welded to the busbar, in particular the inner side of the opening.

5. The method according to claim 1, It is characterized in that - Placing the bushings with their connection regions on the first side of the busbar.

6. The method according to claim 5, It is characterized in that - Placing the sleeve with its connection region on the first side of the busbar so that the sleeve and the connection region of the individual conductors are approximately in the same plane as the first side.

7. The method according to claim 5 or 6, It is characterized in that The busbar, the sleeve and the individual wires are welded to one another starting from the second side by friction spot welding, in particular the individual wires are welded to the sleeve, in particular the inner side of the sleeve, and the sleeve is welded to the busbar.

8. The method according to any one of the preceding claims, It is characterized in that The busbar is formed as a planar component, wherein the contact region is part of a web of the planar component that projects from a longitudinal edge.

9. The method according to claim 8, It is characterized in that After the busbars have been welded together with the sleeves and the individual conductors, the tabs are bent around the longitudinal edges, in particular by more than 45°.

10. The method according to any one of the preceding claims, It is characterized in that - Each sleeve is cut to a fixed length on the end face so that the single strand wire and the sleeve form a substantially planar connection area on the end face of the sleeve.

11. The method according to claim 8 or 9, It is characterized in that A lug is arranged at each of two longitudinal edges lying opposite one another and at least two stranded conductors are welded together to the respective lug.

12. A connection arrangement between at least two stranded conductors and a busbar, in particular a connection arrangement produced according to the method of any of the preceding claims, wherein at least two litz-wire conductors each have an end region, wherein the individual wires of the litz-wire conductors are free of insulation, - Push the sleeves onto the respective end regions, - Press the sleeves onto the individual wires, The connection regions are arranged on the busbar in two spaced-apart contact areas, wherein: The contact areas are located on a common first side of the busbar, and - Starting from a second side of the busbar opposite to the first side, the sleeve, the individual conductors and the busbar are welded together in each contact area.

13. The connection arrangement according to claim 11, It is characterized in that - the individual wires of the stranded conductor are made of aluminium or an aluminium alloy, and / or - the busbars are made of aluminium or an aluminium alloy, and / or -The casing is made of aluminum or an aluminum alloy.

14. A connection arrangement according to any one of claims 11 to 13, It is characterized in that The sleeve has a through hole extending in the longitudinal direction or a blind hole extending in the longitudinal direction, into which the individual wires of the twisted conductor are inserted.

15. A connection arrangement according to any one of claims 11 to 14, It is characterized in that -The sleeve is formed from a metal tube or sheet metal.

16. A connection arrangement according to any one of claims 11 to 14, It is characterized in that - The distal ends of at least two stranded conductors are respectively welded to the busbars.

17. Use of a connection arrangement according to any one of claims 11 to 15 in a motor vehicle, a water vehicle, an aircraft or a launch vehicle, a spacecraft or a satellite.

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