DEVICE AND METHOD FOR ALIGNING AND / OR MASKING SOCKET REELS

Description

[0001] The invention relates to a device and a method for aligning and masking the free ends of plug-in coils of a stator that are to be connected, in particular welded. Plug-in coils are typically hairpins and / or I-pins, although other special shapes are possible. The device comprises features of the preamble of claim 1, and the method comprises features of the independent claim.

[0002] In the production of electromechanical converters, especially electric motors, especially for traction drives, individual winding elements (plug-in coils, e.g. so-called "hairpins") are produced, which are then further processed into a stator winding.

[0003] In order to achieve greater efficiency in electrical machines due to a higher fill ratio, a switch was made from round to rectangular conductor cross-sections. Within the scope of the invention, the use of plug-in coils with any conductor cross-section is possible, for example, round or rectangular cross-sections. During the production of the plug-in coils, appropriate conductor pieces are cut from continuous material and formed into suitable plug-in coils. After positioning the plug-in coils on the stator, they are welded together at their upper free ends or connected in some other way, e.g., by soldering.

[0004] To ensure this welding or joining process is reliable and reproducible, the hairpins to be welded together must be positioned and aligned in a precisely defined position relative to each other to ensure the desired contact. Furthermore, it is desirable to cover or mask the area around the free ends of the plug-in coils to be welded together to prevent welding beads or waste material generated during the welding process from contacting and potentially damaging the remaining sections of the hairpins.

[0005] The object of the present invention is to provide possibilities to position, align and mask plug-in coil arrangements safely, reliably, reproducibly and efficiently in order to subsequently weld or connect them together.

[0006] WO201211969 and WO2019 / 007459 describe devices in which plug-in coils are clamped, aligned, and masked using two masking discs rotating in opposite directions. The two discs act on the plug-in coils at different horizontal planes, thereby generating shear forces. This can result in inadequate alignment and potentially damage to the plug-in coils.

[0007] JP 2013 165615 A ​​shows the contacting in different horizontal planes, so that shear forces can occur. Furthermore, no radial clamping is shown.

[0008] The device and method according to the invention eliminate these problems.

[0009] As already mentioned, alignment and masking serve to prepare for a joining process, especially a welding process. Typically, the free ends of the plug-in coils are welded using irradiation. This is typically done using laser irradiation. The irradiation typically acts on the free ends at the front. The free ends are locally melted from their front sides and connected to each other in the desired configurations.

[0010] The connection can be made in pairs, but more than two ends can also be connected to each other with a weld seam in order to electrically connect the corresponding plug-in coils.

[0011] In an initial configuration, the free ends extend along a longitudinal direction. The free ends refer to the straight end sections of the plug-in coils. The free ends are arranged on concentric circular paths extending in a circumferential direction and in rows extending in a radial direction. Individual "locations" in the rows and circular paths can be free, and individual plug-in coils or their free ends can be arranged in special positions. However, the majority of the free ends are located on the aforementioned rows and circular paths.

[0012] The device comprises a first flat positioning unit and a second flat positioning unit. The positioning units are preferably disc-shaped. In any case, they are flat and thus thin in the longitudinal direction and extended in the radial direction. A substantially circular outer contour is advantageous for easy rotation within the device, but is not absolutely necessary. A small extension in the longitudinal direction allows for the processing of short free ends.

[0013] The first positioning unit has first passages, arranged corresponding to the position of the free ends, for arrangements of free ends to be welded together, and the second positioning unit has second passages, arranged corresponding to the position of the free ends, for arrangements of free ends to be welded together. In other words, the positioning units have passages that are arranged corresponding to the arrangement of the free ends. During operation of the device, a number of free ends to be welded are each arranged in a passage, or the free ends arranged in a passage are welded together. Accordingly, the passages can be designed differently, depending on which plug-in coils are to be connected to one another.The passages can be individual, separate openings, but they can also be interconnected, and a single passage can be part of an opening. The individual passages can be separated from one another by projections, which can, for example, form stops.

[0014] The first positioning unit and / or the second positioning unit are rotatably mounted in the device. The arrangement is such that the positioning units can be rotated relative to one another, in particular both in opposite directions to one another, during an alignment process of the plug-in coils. A rotational movement of the two positioning units relative to one another can thus be provided. Both positioning units can be arranged individually movable in the device. However, one of the positioning units can also be fixedly mounted in the device and only the other positioning unit can be rotatably mounted in the device.

[0015] As the positioning units rotate, the first positioning unit contacts the plug-in coils in the circumferential direction with a first contact section from a first side and pushes them into the desired position. The second positioning unit contacts the plug-in coils in the circumferential direction with a second contact section from a second side and pushes them into the desired position. The positioning units are rotatable relative to each other about a common axis. One or both of the positioning units can be rotatable within the device.

[0016] The second side is opposite the first. In other words, the positioning units contact the free ends from opposite sides.

[0017] The first contact section and the second contact section are arranged in a contact plane orthogonal to the longitudinal direction. In other words, they are at the same height relative to the longitudinal direction. During an alignment process, the free ends therefore contact each other at the same height along the longitudinal direction. This contact at the same height on both sides avoids shear forces and increases the possible positioning accuracy.

[0018] The first positioning unit and the second positioning unit typically lie adjacent to one another. The positioning units can thus lie flat against one another. The longitudinal extension can thus be minimized, which facilitates the processing of short free ends. However, the positioning units can also be designed and arranged in the device such that the first positioning unit is located radially inward of the second positioning unit, and the positioning units extend radially into one another in the region of the passages. The positioning units can therefore lie entirely in one plane.

[0019] The first passages and the second passages each have radial stop sections for arrangements of free ends to be welded together. The stop sections can, in particular, be arranged radially inward. The device further comprises a radial clamping device with a plurality of radial clamping units, each of which is designed and arranged to urge the arrangements of free ends in the superimposed first passages and second passages against the radial stop sections of the first passages and / or the second passages.

[0020] The contact sections thus determine the position of an arrangement of free ends to be welded in the circumferential direction and the radial position is specified by means of the radial stop sections and the radial clamping units.

[0021] The radial clamping units can be moved together in the radial direction via a common drive, in particular a slotted drive. The radial clamping units are preferably movable radially inward for clamping. This allows the radial stop sections to be arranged radially inward, allowing the radial clamping units to utilize the larger installation space available radially outward.

[0022] The radial clamping units can be spring-mounted to limit the maximum contact force in the radial direction during their actuation. The maximum force applied to the free ends is limited to the force of the spring-loaded mounting. The spring-loaded mounting can, for example, be provided in relation to the aforementioned link drive. The link drive acts on the spring, which in turn acts on the respective radial clamping unit. If the contact force exceeds the spring force of the spring, the spring is compressed, and the radial clamping units do not move further, despite continued actuation of the link drive.

[0023] The radial clamping units can each comprise several clamping elements, with each clamping element being individually spring-loaded. A spring-loaded clamping element can be provided for each assembly to be welded or for each passage, so that the assemblies to be welded can each be individually clamped with a defined force. Each of the stop surfaces of the radial clamping units is thus individually spring-loaded.

[0024] The first passages and / or the second passages may have insertion phases on one insertion side, which facilitates the insertion of the ends into the passages.

[0025] The first positioning unit and / or the second positioning unit and / or a link drive element used to actuate the radial clamping units can be rotated in the circumferential direction via a respective linear drive. A linear drive is a reliable and robust way to implement the rotational movement.

[0026] The device may include a cover unit on one welding side. The cover unit may be formed with openings for the free ends.

[0027] The radial clamping unit can be arranged on the welding side of the positioning unit. In particular, the cover unit can be arranged first on the welding side, followed by the radial clamping unit, and then the two positioning units. However, the radial clamping unit can also be arranged on the opposite side. The positioning units are then located between the cover unit and the radial clamping unit.

[0028] The cover unit prevents unwanted material from entering the device during welding and damaging moving parts, for example.

[0029] Part of the device may also be a welding unit designed and arranged to weld the free ends arranged in the passages. Typically, the welding unit is a beam welding unit, in particular a laser welding unit.

[0030] As already explained, part of the invention is also a method for aligning and masking the free ends of plug-in coils of a stator that are to be welded. The alignment and masking serves to prepare for a welding process by which the free ends of the plug-in coils are connected to one another. The free ends are arranged in the configuration already explained above, with radially extending rows and circumferential circular paths.

[0031] The positioning units 20, 22 can be designed and arranged such that they interlock. A section of one of the positioning units can be slidably arranged in a corresponding recess of the other positioning unit 22. In particular, several sections and recesses can be present on the positioning units, each extending into the other. The positioning units can be designed to interlock such that they essentially form a common circular disk (other geometric radial outer and inner contour shapes are also possible; however, a predominantly circular shape is advantageous due to the rotational symmetry).

[0032] The method utilizes a first planar positioning unit and a second planar positioning unit. These can be the previously mentioned positioning units of the device. In particular, the method can be carried out using a device configured as described here.

[0033] The first positioning unit has first passages arranged corresponding to the position of the free ends for arrangements of free ends to be welded together, and the second positioning unit has second passages arranged corresponding to the position of the free ends for arrangements of free ends to be welded together.

[0034] The respective passages can be connected to one another in a radially directed row; in such a case, they are "separated" or delimited from one another by projections. However, the passages can also be separated from one another by continuous material webs.

[0035] The free ends are positioned in the first and second passages. For this purpose, the positioning units can be lowered onto the stator, for example, or the stator can be inserted into the passages from below. The terms "bottom" and "top" do not necessarily refer to the direction of gravity, but rather to the bottom and top of the positioning units. In other words, "lowering onto the stator" can also be considered "lifting" against gravity.

[0036] The first positioning unit and the second positioning unit are then rotated in opposite directions to each other in an alignment process of the plug-in coils.

[0037] The first positioning unit and the second positioning unit contact the plug-in coils on opposite sides in a contact plane orthogonal to the longitudinal direction, so that the first positioning unit and the second positioning unit contact the free ends at the same height along the longitudinal direction.

[0038] In the method, the free ends are urged in a radial alignment step in the radial direction against the respective radial stop sections of the first positioning unit and / or the second positioning unit.

[0039] Part of the method may also be that free ends of assemblies to be welded together are welded together by means of a beam welding step, while the free ends are located in the passages of the positioning unit and the second positioning unit.

[0040] The invention is described in more detail below with reference to the figures, wherein identical or functionally identical elements may be provided with reference numerals only once.

[0041] They show: Figure 1 a device according to the invention in perspective view; Figure 2 the device from Figure 1 in a different perspective view; Figure 3 a view of part of the positioning units in the open state seen from below; Figure 4 a view of part of the positioning units in the closed state seen diagonally from below; Figure 5 a detailed view of part of the positioning units; Figure 6 a part of a radial clamping device with several radial clamping units; and Figure 7 a schematic representation of a radial clamping unit with several radial clamping elements.

[0042] Figure 1 shows a device 10 for aligning and masking free ends 12 of plug-in coils 14 of a stator 16, which is only shown in outline.

[0043] The plug-in coils 14 and their free ends are arranged in pairs, i.e., in pairs 13. In this case, the pairs 13 represent arrangements 26 of free ends 12 to be welded. The arrangements 26 typically comprise pairs of pins, but there may also be, for example, three or more pins in a respective arrangement 26.

[0044] The free ends 12 extend from the stator along a longitudinal direction L and end in their end faces 15, which are typically orthogonal to the longitudinal direction L.

[0045] In the left part of Figure 1 a partial area 11 of the device 10 is shown enlarged and the configuration of the free ends 12 is clearly visible.

[0046] The free ends 12 are arranged on concentric circular paths 30 (represented by a broken line) extending in a circumferential direction U and in rows 32 (represented by a dotted rectangle) extending in the radial direction R.

[0047] Figure 2 shows the device when viewed along the longitudinal direction L from the side of the stator 16, wherein the stator 16 and the plug-in coils 14 are not shown.

[0048] The device 10 has a first planar positioning unit 20 and a second planar positioning unit 22. The two positioning units 20, 22 are rotatable relative to each other about a common axis of rotation 25. (For this purpose, one, but preferably both, of the positioning units 20, 22 can be arranged rotatably in the device 10.)

[0049] The first positioning unit 20 has first passages 24. The first passages 24 are arranged corresponding to the position of the free ends 12 and serve to accommodate arrangements 26 to be welded together, in this case the pairs 13 of free ends 12.

[0050] The second positioning unit 22 also has second passages 28 arranged corresponding to the position of the free ends 12 for arrangements 26 of free ends 12 to be welded together.

[0051] The first passages 24 and the second passages 28 are thus arranged largely congruently in the device 10. The passages 24, 28 can be individual, separate "openings," but, as shown in the figures, they can also be connected to one another, and an individual passage 24, 28 can be part of an "opening," i.e., a material breakthrough. As shown in the figures, the individual passages 24, 28 can be separated from one another by projections (e.g., which, as in the present case, are designed to protrude in the circumferential direction), which can, for example, form stops.

[0052] The first planar positioning unit 20 has a first contact section 34 at free ends 12 for each pair 13 to be contacted, and the second planar positioning unit 22 has a second contact section 38 at free ends 12 for each pair 13 to be contacted (see Figure 5 ).

[0053] The first positioning unit 20 and the second positioning unit 22 are arranged rotatably in the device 10 such that the positioning units 20, 22 can be rotated in opposite directions during an alignment process of the plug-in coils 14. The rotation occurs around the common rotation axis 25.

[0054] The rotation aligns and masks the free ends 12 of the plug-in coils 14. The rotation displaces the first passages 24 and the second passages 28 relative to each other, so that their sides (first contact sections 34 and second contact sections 38) contact the free ends from opposite sides and force them into the desired position. The alignment and masking serves to prepare for a welding process by which the pairs 13 or arrangements 26 of the free ends 12 of the plug-in coils 14 are connected to one another. This is done by beam welding. A corresponding beam welding device can be part of the device 10.

[0055] During alignment, the positioning units 20, 22 are rotated in opposite directions to one another. The first positioning unit 20 contacts the plug-in coils 14 in the circumferential direction U with the first contact section 34 from a first side and pushes them into the desired position. The second positioning unit 22 contacts the plug-in coils 14 in the circumferential direction U with the second contact section 38 from a second side and pushes them into the desired position. Pushing them into the desired position typically only leads to minor changes in position, provided the plug-in coils are already largely correctly aligned. Pushing them into the desired position serves to ensure correct alignment and to ensure that the plug-in coils 14 to be welded together lie well against one another, so that a high-quality weld seam can form.The positioning units 20, 22 are located laterally on the plug-in coils 14 in the circumferential direction U and thus ensure masking.

[0056] The contact between the first contact section 34 and the second contact section 38 is therefore made from different, opposite sides. The first contact section 34 and the second contact section 38 are located in a contact plane 42 orthogonal to the longitudinal direction L. As a result, during an alignment process, they contact the free ends 12 at the same height along the longitudinal direction L. This avoids bending moments and shear forces on the free ends 12. The contact plane 42 is in Fig. 5 represented by a dashed line.

[0057] The first positioning unit 20 and the second positioning unit 22 are adjacent to one another.

[0058] In the embodiment shown, the positioning units 20, 22 interlock. A section 21 of the first positioning unit 20 is slidably arranged in a corresponding recess 23 of the second positioning unit 22. In this case, the positioning units 20, 22 are designed to interlock in such a way that they essentially form a common circular disk (other geometric radial outer and inner contour shapes are also possible; however, a predominantly circular shape is advantageous due to the rotational symmetry).

[0059] The first passages 24 and / or the second passages 28 each have radial stop sections 44 for the arrangements 26 of free ends 12 to be welded together (see Figure 4 and 5 ).

[0060] The device further comprises a radial clamping device 46 with a plurality of radial clamping units 48. The radial clamping units 48 are each designed and arranged to urge the arrangements 26 of free ends 12 to be welded, located in the first passages 24 and second passages 28 arranged one above the other, against the radial stop sections 44 of the first passages 24 and the second passages 28. For this purpose, the radial clamping units 48 each have recesses 60 for the radially outer arrangements 26 of free ends 12 and a stop surface 61 for the radially inner arrangements 26 of free ends 12. In Figure 3 the positioning units 20, 22 are open and part of the radial clamping units 48 is visible. Figure 4 the positioning units 20, 22 are closed and the radial clamping units 48, which are arranged above the positioning units 20, 22, are not visible.

[0061] The radial clamping units 48 are jointly movable in the radial direction R via a link drive with a link drive element 54. The link drive element 54 of the link drive 53 is designed as a disc-shaped element with trajectories 55. One trajectory 55 is provided for each radial clamping unit 48.

[0062] The radial clamping units 48 are further spring-mounted by means of a spring-loaded bearing 49 in order to limit the maximum contact force in the radial direction R during actuation to the force of the spring-loaded bearing 49. The radial clamping units 48 are connected via the spring-loaded bearing 49 to engagement elements 51, which in turn engage with the trajectories 55 of the link drive element 54. When the link drive element 54 is rotated, the engagement elements 51 move along the trajectories 55 and urge the radial clamping units 48 radially inward via the spring-loaded bearings 49. If the free ends 12 come into contact with the radial stop sections 44 on the radial inside, the spring-loaded bearings 49 are compressed when the link drive element 54 is moved further. There is no further movement of the free ends 12, but they are pressed against the respective radial stop section 44 by the tension of the spring bearings 49.The free ends are thus in their intended position for welding and are masked both in the circumferential direction U and in the radial direction R.

[0063] The first passages 24 and the second passages 28 have insertion phases 52 on an insertion side 50 (see Figure 5 ). This facilitates the insertion of the free ends 12 and prevents damage.

[0064] End sections 62 of boundaries 64 of the passages 24, 28 (the boundaries 64 of the first positioning unit 20 and the second positioning unit 22 together form the radial stop sections 44) can be rounded or chamfered, so that the clear width of the passages is increased in the radial direction in the region of these end sections. This allows an assembly 26 to be welded to be removed when the positioning units 20, 22 are open and have a larger weld bead than intended or an asymmetrically placed weld bead.

[0065] The first positioning unit 20, the second positioning unit 22 and the link drive element 54, which serves to actuate the radial clamping units 48, can be brought into rotation in the circumferential direction U about the common axis of rotation 25 via a respective linear drive 57.

[0066] The device 10 has a cover unit 58 on a welding side 56, with slot-like openings for the free ends 12.

[0067] The radial clamping units 48 are arranged on the welding side 56 of the positioning units 20, 22, i.e. in the longitudinal direction between the positioning units 20, 22 and the cover unit 58.

[0068] Part of the invention is also a method for aligning and masking the free ends 12 of the plug-in coils 14 of the stator 16 to be welded. The alignment and masking serves to prepare the welding process by which the free ends 12 of the plug-in coils 14 are connected to one another.

[0069] For this purpose, the previously described positioning units 20, 22 can be used. The free ends 12 of the plug-in coils 14 are arranged in the passages 24, 28 of the positioning units 20, 22 when they are in an "open" position, as shown in Figure 3shown.

[0070] Subsequently, the first positioning unit 20 and the second positioning unit 22 are rotated in opposite directions to each other in an alignment process of the plug-in coils 14. The first contact sections 34 and the second contact sections 38 move towards each other in opposite circumferential directions and reduce the free area of ​​the passages 24, 28 (see Figure 4 ).

[0071] The plug-in coils 14 are contacted on opposite sides in the contact plane 42 at the same height along the longitudinal direction L. At the same time, subsequently, or beforehand, the free ends 12 are urged in the radial direction R against respective radial stop sections 44 of the first positioning unit 20 and / or the second positioning unit 22 by means of the radial clamping units 48.

[0072] The radial clamping units 48 can each comprise a plurality of clamping elements 66, whereby each of the clamping elements 66 can be individually spring-mounted. Such an embodiment is shown schematically in Figure 7 shown. In this embodiment, a spring-loaded clamping element 66 can be provided for each assembly 26 to be welded or for each passage 24, so that the assemblies 26 to be welded can each be individually clamped with a defined force. Each of the clamping elements 66 thus has its own spring-loaded mounting 49. The individual assemblies can thus be precisely positioned and clamped. Manufacturing tolerances of the plug-in coils 14 can thus be individually compensated.

Claims

1. Device (10) for aligning and masking free ends (12) of plug-in coils (14) of a stator (16) to be welded, the alignment and masking serving to prepare a connection process, in particular a welding process, by means of which free ends (12) of the plug-in coils (14) are connected to one another, the free ends (12) extending along a longitudinal direction (L), and the free ends (12) being arranged on concentric circular paths (30) which extend in a circumferential direction (U), and in rows (32) which extend in the radial direction (R), the device (10) comprising a first planar positioning unit (20) and a second planar positioning unit (22), the first positioning unit (20) having first passages (24) for assemblies (26) of free ends (12) to be welded together, which passages are arranged so as to correspond to the position of the free ends (12), and the second positioning unit (22) also having second passages (28) for assemblies (26) of free ends (12) to be welded together, which passages are arranged so as to correspond to the position of the free ends (12), the first positioning unit (20) and / or the second positioning unit (22) being arranged rotatably in the device (10) such that the positioning units (20, 22) can be rotated relative to one another, in particular in opposite directions, during an alignment process of the plug-in coils (14), so that the first positioning unit (20) contacts the plug-in coils (14) in the circumferential direction (U) with a first contact portion (34) from a first side (36) and pushes them into the desired position and the second positioning unit (22) contacts the plug-in coils (14) in the circumferential direction (U) with a second contact portion (38) from a second side (40) and pushes them into the desired position, the second side (40) being opposite the first side (36), the first contact portion (34) and the second contact portion (38) lying in a contact plane (42) orthogonal to the longitudinal direction (L) so that during an alignment process they contact the free ends (12) at the same height along the longitudinal direction (L), the first passages (24) and / or the second passages (28) forming radial stop portions (44) for assemblies (26) of free ends (12) to be welded together, characterized in that the device further comprises a radial clamping device (46) having a plurality of radial clamping units (48), each of which is designed and arranged to push the assemblies (26) of free ends (12) to be welded, located in superimposed first passages (24) and second passages (28), against the radial stop portions (44) of the first passages (24) and / or the second passages (28).

2. Device according to claim 1, characterized in that the first positioning unit (20) and the second positioning unit (22) abut one another in the longitudinal direction, in particular have interlocking portions, in particular one of the positioning units (20, 22) has a portion which is displaceably arranged, in particular guided, in a recess of the other positioning unit (20, 22).

3. Device according to claim 1, characterized in that the first positioning unit (20) is arranged radially inwardly from the second positioning unit (22) and the positioning units (20, 22) extend into one another in the radial direction in the region of the passages (24, 28).

4. Device according to any of the preceding claims, characterized in that the radial clamping units (48) can be moved together in the radial direction (R) via a common drive, in particular a link drive.

5. Device according to any of the preceding claims, characterized in that the radial clamping units (48) are spring-mounted in order to limit a maximum contact force in the radial direction (R) during their actuation on the force of the spring mount (49), in particular the radial clamping units (48) each comprising a plurality of clamping elements (66), each of the clamping elements (66) being individually spring-mounted, in particular a spring-mounted clamping element (66) being provided for each assembly (26) to be welded or for each passage (24).

6. Device according to any of the preceding claims, characterized in that the first passages (24) and / or the second passages (28) have insertion phases (52) on an insertion side (50).

7. Device according to any of the preceding claims, characterized in that the first positioning unit (20) and / or the second positioning unit (22) and / or a link drive element (54) which is used to actuate the radial clamping units (48) can be brought into rotation in the circumferential direction (U) via a particular drive, in particular a linear drive (57), or it being possible for the first positioning unit (20) and the second positioning unit (22) to be moved in opposite directions via a common drive.

8. Device according to any of the preceding claims, characterized in that the device (10) comprises a cover unit (58) on a welding side (56), which cover comprises openings for the free ends (12).

9. Device according to any of the preceding claims, characterized in that the radial clamping units (48) are arranged on the welding side (56) of the positioning units (20, 22).

10. Device according to any of the preceding claims, characterized in that the positioning units (20, 22) have boundaries (64) of the passages (24, 28), their end portions (62) being rounded such that that in the open state of the positioning units (20, 22) the clear width of the passages (24, 28) in the radial direction is greater than in the closed state.

11. Method for aligning and masking free ends (12) of plug-in coils (14) of a stator (16) to be welded, wherein the alignment and masking serve to prepare a welding process, by means of which the free ends (12) of the plug-in coils (14) are connected to one another, wherein the free ends (12) extend along a longitudinal direction (L), and wherein the free ends (12) are arranged on concentric circular paths (30) which extend in a circumferential direction (U), and in rows (32) which extend in the radial direction (R), wherein a first planar positioning unit (20) and a second planar positioning unit (22) are used, wherein the first positioning unit (20) has first passages (24) for assemblies (26) of free ends (12) to be welded together, which passages are arranged so as to correspond to the position of the free ends (12), and the second positioning unit (22) also has second passages (28) for assemblies (26) of free ends (12) to be welded together, which passages are arranged so as to correspond to the position of the free ends (12), and wherein the free ends are arranged in the first passages (24) and the second passages (28), and subsequently the first positioning unit (20) and the second positioning unit (22) are rotated relative to one another, in particular in opposite directions, during an alignment process of the plug-in coils (14), so that the first positioning unit (20) and the second positioning unit (22) contact the plug-in coils (14) at opposite sides in a contact plane (42) orthogonal to the longitudinal direction (L), so that the first positioning unit (20) and the second positioning unit (22) contact the free ends (12) at the same height along the longitudinal direction (L), wherein the first passages (24) and / or the second passages (28) have radial stop portions (44) for assemblies (26) of free ends (12) to be welded together and the assemblies (26) of free ends (12) to be welded, located in superimposed first passages (24) and second passages (28), are pushed by means of a plurality of radial clamping units (48) of a radial clamping device (46) against the radial stop portions (44) of the first passages (24) and / or the second passages (28).

12. Method according to claim 11, characterized in that free ends (12) of assemblies (26) to be welded together are welded together by means of a beam welding step, while the free ends (12) are located in the passages (24, 28) of the positioning unit (20) and the second positioning unit (22).