Method for coupling electrical cable with contact piece

Abstract

To provide a process stability in coupling a contact piece and a cable, and a method for improving quality of the coupling.SOLUTION: Axial direction end parts of a plurality of conductive wires 3 of a cable 1 are secured by a tightening tool before introduction into a concave part 8 of a crimp region 6. Therefore, the axial direction end parts of the conductive wires protrude from the tightening tool in the axial direction. Moreover, the end parts of several conductive wires protruding from the tightening tool in the axial direction are sheared by a cutting tool in a lateral direction. Therefore, by generating a closed end face 9 at the axial direction end parts of the wire 3, by introducing axial direction end parts of the conductive wires into the concave part 8, and by melting the end face 9 which is closed and positioned within the concave part 8 with radiation energy of radiation directed to the end face 9, the plurality of conductive wires are welded to a contact piece 5.SELECTED DRAWING: Figure 1a

Description

[Technical Field]

[0001] The present invention relates to a method for coupling an electrical cable having a plurality of conductive strands to a contact piece, wherein the contact piece is molded with a crimping area having a central recess at least partially surrounded by a crimping tab; and Axial ends of the plurality of conductive wires are introduced into the recesses and compressed to form electrical connections with the crimp tabs. [Background technology]

[0002] When preparing an electrical cable, contact pieces, such as cable lugs or contact pins, are often attached to the ends of the cable, with which an electrical connection can be formed between the cable and a cable connection when the cable is in use. For the connection of the cable to the contact piece, crimp connections are often used, by means of which the electric cable (or the electric conductor of this electric cable) is pressed into the crimped part of the contact piece. In order to form an operationally reliable, durable and electrically well-conducting connection between the contact piece and the cable, the cable and the contact piece can also be further welded after crimping, likewise by means of, for example, laser welding. Such a connection method is known from US Pat. No. 5,629,997 or US Pat. No. 5,629,997.

[0003] This type of bonding method is, however, complex and difficult in terms of process technology. First, the electrical insulation of the cable must be removed to expose the electrical conductors of the cable without damaging the conductors. The exposed conductors must then be placed in the crimped portion and pressed into the crimped portion, ensuring that a good electrical connection is made without damaging the conductors. During welding, welding splashes, oxidation, or smoke residues may occur, which may also damage the cable. When electrical conductors made of aluminum are used, there is an additional problem that an electrically insulating oxide layer quickly forms on the surface of the aluminum, which may impair electrical conductivity and cause damage during welding. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] DE 103 58 153 A [Patent Document 2] DE 10 2009 056 799A Summary of the Invention [Problem to be solved by the invention]

[0005] The object of the present invention is to improve the process stability during the formation of the bond between the contact piece and the cable, as well as the quality of such a bond. [Means for solving the problem]

[0006] This issue is the axial ends of the conductive strands are fixed by a clamping tool prior to their introduction into the recess; Thus, the axial ends of the plurality of conductive strands protrude axially from the clamping tool by a length, and the ends of the plurality of conductive strands protruding axially from the clamping tool are sheared transversely by a cutting tool; Therefore, a closed end surface is generated at the end of the wire in the axial direction. the axial ends of the plurality of conductive strands are introduced into the recess; and a closed end surface disposed within the recess is melted by radiant energy of radiation directed toward the end surface, thereby welding the plurality of conductive strands to the contact piece; is solved by [Effects of the Invention]

[0007] This shearing of the wires creates a closed end face at the axial end of the cable, which on the one hand facilitates the introduction of the cable into the crimping area and, on the other hand, also improves the end-side welding after crimping, both of which increase the process stability of the joining method and also the quality of the joint formed.

[0008] If the closed end face is positioned in the recess axially rearwardly from the edge of the crimping area opposite the cable, end face welding can be improved.

[0009] Depending on the use, the ends of the strands axially protruding from the clamping tool are sheared normal to the longitudinal axis of the cable; Thus, the end faces are oriented normal to the longitudinal axis of the cable, or sheared at an angle relative to the longitudinal axis of the cable; The end faces are therefore oriented at an angle relative to the longitudinal axis of the cable.

[0010] The inclined end face has certain advantages. On the one hand, radiation, such as a laser beam, which should be applied essentially normal to the end face, is directed in one direction, away from the longitudinal axis of the cable. This improves reliability during welding, since the radiation cannot escape from the locking gate of the welding chamber, into which the cable is introduced in the direction of its longitudinal axis. Accordingly, contact pieces can also be welded, at which radiation cannot be directed in the longitudinal direction of the cable through the functional part of the contact piece. In particular, the beveled end faces also improve the tensile strength and also the electrical conductivity of the connection.

[0011] It may be provided that in the region of the edge a notch is provided in the crimping tab to prevent the end face arranged in the recess from blocking the radiation.

[0012] Light blocking can also be prevented if the edge is beveled at an angle relative to the longitudinal axis of the cable and the end face is beveled at an angle steeper than the edge angle, with a region of this end face being located closer to the edge than the rest of the end face, thus making a larger area of ​​the end face accessible to radiation.

[0013] The axial ends of the wires are advantageously radially compressed, advantageously gas-tightly compressed, prior to the shearing. The resulting compressed areas with small hollow spaces between the wires can improve the electrical conductivity on the one hand, and also the welding, since the radiation energy can penetrate better into the axial ends on the other hand.

[0014] Often, on the surface of the contact piece there is a coating, for example a nickel layer. In order to improve the electrical connection, such a coating on the surface of the contact pieces in the crimping area can be at least locally removed prior to the crimping. In order to improve the welding quality, it is also possible that such coatings on the surface of the contact piece in the welding area and / or in the area in front of the end face in the recess are at least locally removed prior to the welding. In a particularly advantageous embodiment, the coating is removed by radiation, which radiation is also used for welding.

[0015] The invention will now be explained in more detail in connection with FIGS. 1a to 8, which show, by way of example, schematic and without limitation, advantageous embodiments of the invention. [Brief explanation of the drawings]

[0016] [Figure 1a] 1 is a diagram of an electrical conductor having a contact piece and a cable coupled to the contact piece; [Figure 1b] 1 is a diagram of an electrical conductor having a contact piece and a cable coupled to the contact piece; [Figure 2a] 10A-10C are diagrams of a method for forming a bond between a contact piece and a cable. [Figure 2b] 10A-10C are diagrams of a method for forming a bond between a contact piece and a cable. [Figure 2c] 10A-10C are diagrams of a method for forming a bond between a contact piece and a cable. [Figure 2d] 10A-10C are diagrams of a method for forming a bond between a contact piece and a cable. [Figure 2e] 10A-10C are diagrams of a method for forming a bond between a contact piece and a cable. [Figure 2f] 10A-10C are diagrams of a method for forming a bond between a contact piece and a cable. [Figure 3a] 1 is a diagram of the shearing of the axial ends of the strands of a cable with the end faces normal to the longitudinal axis of the cable. FIG. [Figure 3b] 1 is a diagram of the shearing of the axial ends of the strands of a cable with the end faces normal to the longitudinal axis of the cable. FIG. [Figure 4a] FIG. 1 is a diagram of shearing the axial ends of the wires of a cable with the end faces at an angle inclined relative to the longitudinal axis of the cable. [Figure 4b]FIG. 1 is a diagram of shearing the axial ends of the wires of a cable with the end faces at an angle inclined relative to the longitudinal axis of the cable. [Figure 5] 1 is a diagram of one embodiment of a welding chamber for welding a crimped cable with contact pieces. FIG. [Figure 6a] 1 is a diagram of an electrical conductor having a contact piece and a cable with an inclined end face coupled to the contact piece; [Figure 6b] 1 is a diagram of an electrical conductor having a contact piece and a cable with an inclined end face coupled to the contact piece; [Figure 7a] 1 shows an electrical conductor with a contact piece and a cable connected to the contact piece, the cable having a beveled end face and a cutout for a laser beam in the region of the edge. [Figure 7b] 1 shows an electrical conductor with a contact piece and a cable connected to the contact piece, the cable having a beveled end face and a cutout for a laser beam in the region of the edge. [Figure 8] FIG. 1 is a diagram of one embodiment of a welding chamber for a cable having a beveled end face. DETAILED DESCRIPTION OF THE INVENTION

[0017] 1a and 1b show a finished prepared electrical conductor according to the present invention. An electrical cable 1 having an outer electrical insulation 2 is stripped at one axial end by removing the outer insulation, thus exposing the electrical wires 3 of the cable 1. The exposed wires 3 are introduced into the crimping area 6 of the contact piece 5. The crimping area 6 is shown cut away in FIG. 1a to show the wires 3. The crimping area 6 is formed by a crimping tab 7, which at least partially surrounds a recess 8, in which the electrical wires 3 are arranged. The wires 3 in the recess 8 are pressed by the crimping tab 7 in a known manner by means of a crimping tool. After pressing, the wires 3 and the contact pieces 5 are welded to one another in the region of the crimping tabs 7. This welding is carried out at the end faces 9 of the wires 3, which are arranged in the recesses 8. For this purpose, the end faces 9 of the wires 3 are preferably axially offset rearward from the end edge 10 of the crimping region 6, facing away from the cable 1. In order to melt the wire 3 in the region of the end face 9, the welding is carried out by means of radiant energy, preferably with a laser beam, which is directed towards the end face 9. Due to adhesive forces, the melted and also finished end face 9 of the wire forms a concave surface, as shown in FIG.

[0018] In Figures 1a and 1b, the cable 1 has an outer insulation 2 which, in order to form an electrical connection between the wires 3 of the cable 1 and the contact pieces 5, must first be removed in the region of the axial end of the cable 1 to expose the wires 3. Of course, a cable 1 without insulation 2 can also be used, whereby the step of stripping the insulation can likewise be omitted. It is also possible for the cable to already be stripped at the axial ends, so that in this situation too the step of stripping the insulation can likewise be omitted.

[0019] With figures 2a to 2f a method for the formation of an electrical connection between the conductive strands 3 of the cable 1 and the contact pieces 5 is described.

[0020] At one axial end, the contact piece 5 has a crimping tab 7, which is already bent upwards in Fig. 2a, and at the other axial end, a functional part of the contact piece 5, such as a contact plug, contact pin, etc., is formed. Using a forming tool 11 and a mandrel 12, the crimping area 6 is formed by deforming the crimping tabs 7 around the mandrel 12 in the desired manner. In the illustrated embodiment, the crimping area 6 has a recess 8 with a conically converging entry area that transitions into a cylindrical pressure area. The wires 3 of the cable 1 are introduced through the entry area into the recess 8, the cone facilitating this introduction. End faces 9 of the wires 3 are located within the pressure area of ​​the crimping area 6. The recesses 8 can, of course, however, have any other suitable shape and geometry as well.

[0021] After deformation, the crimp tabs 7 lie in contact with each other on the outer periphery, typically at the crimp tab abutment 4 (FIG. 1b). The crimp tab 7 may also be shaped so that it forms a crimp lock on the outer circumferential surface of the crimp tab abutment portion 4, which may result in better tying of the crimp tab 7.

[0022] 2a and 2b, can, of course, also be omitted if a contact piece 5 is used which has an already fully formed crimping area 6. The steps according to FIGS. 2a and 2b should be regarded accordingly, i.e. as optional.

[0023] In FIG. 2c, the axial end of the wire 3 is introduced into the recess 8 of the crimping area 6, so that the end face 9 of the wire 3 is positioned axially rearward from the edge 10 of the crimping area 6 opposite the cable 1 and is located in this recess 8.

[0024] In step 2d of Fig. 2, the wires 3 are pressed in a known manner by means of the crimping tabs 7 in the depressions 8 of the crimping area 6 using a crimping tool 13 (indicated by the arrows). Advantageously, this depression is 0.2-0.5 mm larger than the finished pressed volume. This makes it possible to avoid crimping defects and also reduces the risk of crushing for the wires 3 (crushing of individual wires 3 between the crimping tabs). The risk of crushing can also be reduced by arranging the crimp tab abutments 4 at an angle to the longitudinal axis of the cable 1 (as shown in Figure 1b).

[0025] The cable 1 with the crimped contact pieces 5 is then moved into a welding chamber 20, in which the strands 3 are welded to the crimping tabs 7 (FIG. 2e). For this purpose, radiation, preferably electromagnetic radiation such as a laser beam 21, is directed towards the end face 9, preferably essentially normal to this end face 9, so that the strands 3 are heated and melted by radiant energy in the region of the end face 9. The crimping tabs 7 are preferably not actively heated by the radiation.

[0026] The heating of the end faces 9 by radiation is advantageously carried out in such a way that firstly the edge regions of the pressed strands 3 and then the inner regions of these pressed strands 3 are heated.

[0027] Figure 2f shows the completed welded conductor consisting of the cable 1 and the contact piece 5. Figure 2f also shows the concave surface of the completed end face 9, which is formed by the adhesion of the fused end faces 9 of the wires.

[0028] Prior to the introduction of the wire 3 into the recess 8 of the crimping area 6, the axial end of this wire 3 is pretreated according to the invention as explained on the basis of Figures 3a and 3b.

[0029] The axial end of the wire 3 is fixed in a clamping tool 33, for example in the form of two clamping jaws 30, 31 that are movable relative to one another, with the axial end of the wire 3 protruding freely from the clamping tool 33 by a predetermined axial length L. By means of the cutting tool 32, the axial ends of the wires 3 protruding from the clamping tool 33 are sheared in a transverse direction Q (transverse to the longitudinal direction of the wires 3). Shearing in the transverse direction Q produces not only a clean end face 9 but also a closed cut surface, since the ends of the wires 3 are compressed at the cutting point due to deformation during shearing or are additionally cold welded. The finished cut surface forms the end face 9 of the wire 3. The cutting edge 34 of the cutting tool 32 is preferably obtuse, as this helps to create a closed cut surface 9. Likewise, the cutting edge 34 can be concave or convex, as indicated by the dashed lines in FIG. 3a, if desired.

[0030] The strands 3 can not only be fixed by the clamping tool 33, but also simultaneously radially pressurized, preferably gas-tightly, at their axial ends, during which the strands 3 are radially crushed, for example by the clamping jaws 31, 32, in order to reduce the hollow spaces between the individual strands 3 in the pressurized area. During this gas-tight pressing, the hollow space in the pressing area is eliminated, which can improve the electrical conductivity at the transition of the electrical connection between the wire 3 and the contact piece 5. Due to the pressing, a corresponding radial compressive force acts on the wire 3.

[0031] However, it is also possible for such pressing to be implemented as a separate process step, in which case the axial ends are pressed by a clamping tool in a separate device prior to shearing.

[0032] The clamping jaws 31, 32 advantageously have a non-circular inner shape for pressure application, for example an oval or elliptical shape, since in particular gas-tight pressure application can be more easily achieved within a non-circular shape.

[0033] Additionally, the axial ends of the wires 3 can likewise be shaped axially during pressing, preferably according to the shape of the crimping region 6. Advantageously, during pressing at the axial ends, a cylindrical region is formed, which transitions into a conical region and then optionally into a further rounded entry region. Such a shape in the axial direction can advantageously be used in the crimping region 6, as shown in FIG. 1a. If the axial ends of the wires 3 are shaped similarly to or interdigitated with the crimping region 6, then due to this pre-shaping less deformation work needs to be applied during crimping. In the case of gas-tight pressing, the wires 3 are gas-tightly pressed in a cylindrical region, i.e. at the axial ends of the wires 3.

[0034] The axial ends of the wires 3, however, do not necessarily have to be sheared perpendicular to the longitudinal axis of the wires 3 or cable 1; rather, as shown in Figures 4a and 4b, the end faces 9 can also be formed at a certain angle α to the longitudinal axis.

[0035] The closed end face 9 produced by shearing has advantages, particularly when welding the end face of the wire 3 to the crimp tab 7 . On the one hand, this allows the axial ends of the wires 3 to be introduced more easily and reliably into the recesses 8, since no individual wires 3 are twisted. On the other hand, this allows the end faces 9 to be better heated by radiation, preferably by the laser beam 21. In both cases, this leads to higher process stability. If the axial ends of the wires 3 are further compressed, the end region for welding can be even better heated.

[0036] However, this shearing can just as easily be incorporated into the overall process of forming the electrical bond. It only requires a short time and can be performed immediately before welding. This is a particular advantage, especially when the wires 3 are made of a material, such as aluminum, that oxidizes quickly in the surrounding atmosphere, such as in ambient air. This shearing creates a bare, oxide-free surface, which improves welding in particular, as well as the quality of the electrical bond formed.

[0037] 5 shows a possible embodiment of a welding chamber 20 for welding the wire 3 to the contact piece 5 by means of a laser 22, whereby different suitable respective radiation sources can likewise be used for generating the radiation. The cable 1 with the crimped contact piece 5 is introduced into the welding chamber 20 through a locking gate 23. To prevent the unintended release of the laser beam 21 from the welding chamber 20, the locking gate 23 can be closed around the cable 1. In order for the direction of the laser beam 21 to deviate from the longitudinal axis, the cable 1 can likewise be bent at an angle to the longitudinal axis of the cable 1 in the welding chamber 20. For this purpose, a suitable device 25 can be provided in the welding chamber 20 for bending the cable 1, for example by lifting the cable end. This is likewise beneficial in order to prevent the laser beam 21 from being accidentally released from the welding chamber 20 through the locking gate 23. This is particularly advantageous when the end faces 9 of the strands 3 are oriented essentially normal to the longitudinal axis of the cable 1 and the laser beam 21 is to be applied essentially normal to the end faces 9 during welding.

[0038] In order to hold the contact piece 5, preferably in the area of ​​the crimping region 6, at least during welding, a holding device 28 can likewise be provided in the welding chamber 20.

[0039] The laser beam 21 can be generated from a laser 22 and can be injected into the welding chamber 20 through a window 24. It is however also possible that the laser 22 is disposed within the welding chamber 20 as well.

[0040] The laser 22 is optionally equipped with known devices for directing the laser beam 21 to different locations of the desired area, for example the end face 9 .

[0041] A protective gas nozzle 27 can also be provided in the welding chamber 20 to supply protective gas to the welding location during welding, thereby improving the quality of the welded joint.

[0042] In order to extract the welding vapor and possibly the protective gas, an extraction device 26 can also be provided in the welding chamber 20, preferably in the vicinity of the welding position. This can improve the welding quality.

[0043] The suction device 26 and / or the supply of protective gas to the welding location can create an air flow that reduces adverse welding effects such as oxidation, welding splashes, smoke residue, and the like.

[0044] 6a and 6b show an embodiment in which the end faces 9 are not oriented normal to the longitudinal axis of the cable 1, but rather at an angle deviating from 90°. To facilitate welding, it is also possible for the end edges 10 of the crimping area 6 to be inclined at a similar or the same angle.

[0045] The advantage of an end face 9 beveled in this manner is that radiation, for example a laser beam 21 that should be directed essentially normal to the end face 9, is essentially directed in one direction away from the longitudinal axis of the cable 1. This prevents this radiation from being able to escape through the locking gate 23 of the welding chamber 20 without the cable 1 having to bend in the welding chamber 20, as can be seen in FIG.

[0046] Furthermore, the inclined end face 9 allows machining of the contact piece 5, such as in a complete contact pin, such that the functional part of this contact piece does not provide any passage for radiation, for example a laser beam 21.

[0047] The beveled end faces 9 additionally improve the tensile strength and electrical conductivity of the bond as well.

[0048] The beveled edge 10, however, prevents radiation such as laser beam 21 from reaching a predetermined area of ​​the end face 9 within the recess 8 of the crimped area 6 because this predetermined area is blocked by the edge 10. To prevent this, a cutout 14 can be provided in the crimping tab 7 in the region of the edge 10, through which radiation can also reach the above-mentioned shaded region of the end face 9. This is illustrated in Figures 7a and 7b.

[0049] Such a notch 14 can be produced after crimping by a finishing machining process such as milling or grinding, or can be pre-manufactured already in the crimping tab 7, for example in the punching of the contact piece 5 made of sheet metal. It is also possible to burn off parts of the crimping tab 7 that interfere with welding with radiation, such as a laser beam 21. For this purpose, this radiation can be generated, for example, with different powers. In yet another alternative, the angles of the edge 10 and the end face 9 can be chosen differently. In the radiation blocking region, the end face 9 can be arranged only slightly away from the edge 10 and at a steeper angle than the edge 10.

[0050] 8 shows a welding chamber 20 with, for example, a laser 22 as a radiation source, in which a cable 1 with an inclined end face 9 is welded end-side to a contact piece 5. The laser beam 21, which is to be applied essentially normal to the end face 9, is directed in a direction different from the longitudinal axis of the cable 1 and therefore cannot be released through a locking gate 23. Furthermore, in such an embodiment, any device 25 for bending the cable 1 is not necessary either.

[0051] Often the contact pieces 5 are stamped from a strip of material and bent to the desired shape, and the strip of material is often provided with a protective coating, such as a nickel layer, on its surface. Such a nickel layer can impair the weld quality as well as the electrical conductivity. It is therefore advantageous to remove the coating, if present, prior to crimping, at least at the location of the contact piece 5 where the electrical connection is to be made or welded. This (partial) removal of the coating can be carried out mechanically, thermally or chemically. For mechanical removal of this coating, for example, the inner surface of the crimping tab 7 can be worked with an abrasive brush. For chemical removal, etching chisels or spray nozzles can be used. For thermal removal, vaporization is possible in the intended area using radiation, for example, a laser. In an advantageous embodiment, after crimping and before welding, the coating on the inside of the crimp tab 7 just before the end face 9 in the cutout 8 is removed in a welding chamber 20 using a laser beam 21 .

[0052] It is also possible that the wires 3 and the contact pieces 5 are firstly crimped inside the welding chamber 20. In such an embodiment, radiation, such as a laser beam 21, can also be used to remove the coating of the contact portions at least locally in the crimping area. The present application relates to the invention described in the claims, but may also include the following as other aspects. 1. A method for coupling an electrical cable (1) having a plurality of conductive strands (3) to a contact piece (5), comprising: wherein the contact piece (5) is formed with a crimping area (6) having a central recess (8) at least partially surrounded by a crimping tab (7); and In the method in which the axial ends of the conductive strands (3) are introduced into the recesses (8) and pressurized to form electrical connections with the crimping tabs (7), the axial ends of the conductive strands (3) are fixed by a clamping tool (33) before being introduced into the recesses (8), Therefore, the axial ends of the conductive strands (3) protrude from the clamping tool (33) in the axial direction by a length (L), and the ends of the conductive strands (3) protruding from the clamping tool (33) in the axial direction are sheared laterally by the cutting tool (32), Therefore, a closed end face (9) is formed at the end of the wire (3) in the axial direction. The axial ends of the conductive strands (3) are introduced into the recesses (8); and an end surface (9) of the closed recess (8) is melted by radiant energy of radiation directed toward the end surface (9), thereby welding the plurality of conductive strands (3) to the contact piece (5); A method characterized by: 2. The method according to claim 1, characterized in that the closed end face (9) is positioned in the recess (8) axially offset rearward from the edge (10) of the crimping area (6) opposite the cable (1). 3. The ends of the wires (3) protruding axially from the clamping tool (33) are sheared normal to the longitudinal axis of the cable (1); 2. The method according to claim 1, characterized in that the end face (9) is therefore oriented normal to the longitudinal axis of the cable (1). 4. The ends of the plurality of wires (3) protruding from the tightening tool (33) in the axial direction are sheared at an angle (α) relative to the longitudinal axis of the cable (1); 10. The method according to claim 1, characterized in that the end face (9) is therefore oriented at an angle (α) relative to the longitudinal axis of the cable (1). 5. The method according to claim 4, characterized in that a notch (14) is provided in the crimping tab (7) in the region of the edge (10) to prevent the end face (9) located in the recess (8) from blocking the radiation. 6. The method according to claim 4, characterized in that the edge (10) is beveled at an angle (α) relative to the longitudinal axis of the cable (1) and the end face (9) is beveled at an angle steeper than the angle of the edge (10). 7. Method according to claim 1, characterized in that the axial ends of the strands (3) are radially pressurized, advantageously airtightly, before the shearing. 8. A method according to any one of claims 1 to 7, characterized in that the coating on the surface of the contact piece (5) in the crimping area (6) is at least locally removed prior to crimping. 9. A method according to any one of claims 1 to 7, characterized in that the coating on the surface of the contact piece (5) in the welding area and / or in the area in front of the end face (9) in the recess (8) is at least locally removed prior to the welding. 10. The method according to claim 8 or 9, wherein the coating is removed by radiant energy. [Explanation of symbols]

[0053] 1 cable 2. Outer insulation 3 wire 4 Crimp tab contact area 5 Contact piece 6 Crimping Area 7 Crimp Tabs 8 recess 9 End face 10 Edge 11 Forming tools 12 mandrels 13 Crimping tool 14 Notch 20 Welding Chamber 21 Laser beam 22 Laser 23 Locked Gate 24 Window section 25 Device for bending cables 26 Suction device 27 Protective gas nozzle 28 Holding device 31 Clamping jaw 32 Clamping jaw 33 Fastening tools 34 Cutting edge α angle L Axial length Q Horizontal

Claims

1. A method for coupling an electrical cable (1) having a plurality of conductive strands (3) to a contact piece (5), comprising: In this case, the contact piece (5) is formed with a crimping area (6) having a central recess (8) at least partially surrounded by a crimping tab (7), and A method in which axial ends of a plurality of conductive wires (3) are introduced into the recesses (8) and pressed to form electrical connections with the crimping tabs (7), wherein the axial ends of the plurality of conductive wires (3) are fixed by a clamping tool (33) before being introduced into the recesses (8); Therefore, the axial ends of the plurality of conductive strands (3) protrude from the clamping tool (33) in the axial direction by a length (L), and the ends of the plurality of conductive strands (3) protruding from the clamping tool (33) in the axial direction are sheared laterally by the cutting tool (32); Thus, a closed end face (9) is generated at the axial end of the wire (3), Axial ends of a plurality of conductive strands (3) are introduced into the recess (8); and The end surface (9) disposed within the closed recess (8) is melted by radiant energy of the radiation directed toward the end surface (9), thereby welding the plurality of conductive strands (3) to the contact piece (5); A method characterized by:

2. A method as described in claim 1, characterized in that the closed end face (9) is positioned within the recess (8) axially shifted rearward from the edge portion (10) of the crimping area (6) opposite the cable (1).

3. the ends of the strands (3) protruding axially from the clamping tool (33) are sheared normal to the longitudinal axis of the cable (1); 2. A method according to claim 1, characterized in that the end face (9) is therefore oriented normal to the longitudinal axis of the cable (1).

4. The ends of the wires (3) protruding axially from the clamping tool (33) are sheared at an angle (α) relative to the longitudinal axis of the cable (1); 2. A method according to claim 1, characterized in that the end face (9) is therefore oriented at an angle (α) relative to the longitudinal axis of the cable (1).

5. The method described in claim 4, characterized in that a cutout portion (14) is provided in the crimped tab (7) in the area of ​​the edge portion (10) to prevent radiation from being blocked at the end face (9) arranged in the recess portion (8).

6. A method as described in claim 4, characterized in that the end edge portion (10) is inclined at an angle (α) relative to the longitudinal axis of the cable (1) and the end face (9) is inclined at an angle steeper than the angle of the end edge portion (10).

7. A method as described in claim 1, characterized in that the axial ends of the wire (3) are radially pressurized, preferably airtightly pressurized, before shearing.

8. A method as described in claim 1, characterized in that the coating on the surface of the contact piece (5) within the crimping area (6) is at least locally removed before crimping.

9. 2. The method according to claim 1, wherein the coating on the surface of the contact piece (5) in the welding area and / or in the area in front of the end face (9) in the recess (8) is at least locally removed prior to welding.

10. The method of claim 8 or 9, wherein the coating is removed by radiant energy.

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