Production process for an electrically conductive winding, and an electrically conductive winding

Abstract

The present invention relates to a production process for an electrically conductive winding for a rotating electric machine and to an electrically conductive winding (100) which is intended for a rotating electric machine and has a main winding section (10) and at least one winding head section (20), which forms an axial end of the winding (100). The conductor ends (12, 21) of conductor elements (11, 22) of the main winding section (10) and of the at least one winding head section (20) are simultaneously connected to one another by means of a vibration- or friction-welding connection technique, with the construction of the winding (100) providing the suitable conductor sections (11, 22) and such assigned positioning and fixing of these conductor sections opposite one another as is required for the connection technique.

Description

[0001] Manufacturing method of an electrically conductive winding and electrically conductive winding

[0002] The present invention relates to a manufacturing method for an electrically conductive winding for a rotating electrical machine, and to an electrically conductive winding for a rotating electrical machine having a winding main portion and at least one winding head portion forming an axial end of the winding.

[0003] Windings for generating electromagnetic fields on a rotor or stator of a rotating electrical machine, such as an electric motor or generator, are known in the art. These windings comprise a large number of turns or conductor loops. The windings are produced, for example, in a known manner from a copper wire wound around a structure such as an iron core. So-called hairpin windings are increasingly being used to manufacture motors with high torques and correspondingly high currents. Hairpin windings are generally characterized by a larger, often rectangular cross-section, which permits larger currents and enables a high packing density of turns in the installation space of the winding. Individual turns of the hairpin winding are composed of pre-formed, curved conductor loops, which are twisted together at one axial end of the winding if necessary and then connected to one another by welding.

[0004] The production of certain types of hairpin windings is associated with high manufacturing costs, as a large number of connections are required between the conductor loops. Each individual connection affects both the electrical and mechanical quality of the winding. In particular, a single connection with the lowest connection quality among the numerous connections determines the total electrical resistance of a hairpin winding.

[0005] In modern manufacturing processes, the conductor sections are joined using laser welding technology, which creates a bonded joint achieved through a locally focused, high heat input, which must be precisely positioned at all ends of the conductor loops. To achieve an economically viable throughput of the manufacturing process, the individual welding processes must be performed sequentially, each within a very limited time.

[0006] However, it is known from manufacturing technology that welding techniques using a beam-like heat source, such as laser welding, always involve locally intense and inhomogeneous heat input into the material structure. Thus, when viewed microscopically, laser welding results in less uniformity in the molten material. The formation of cavities or other inclusions or deformities in the weld can significantly impair the electrical properties of the entire number of joints. The heat input during the numerous welding processes can also lead to damage, such as melting of an insulating layer or insulating paint layer on a conductor.

[0007] Secondly, the quality of laser welding depends to a large extent on the dimensional accuracy of the positioning of the conductor ends to be joined and the alignment of the laser at each individual connection. Due to a chain of tolerances in previous manufacturing steps of forming or preforming the conductor loops, e.g., due to the partially elastic properties of the material or wear of the forming tool, as well as the positioning or twisting of free ends of the assembled conductor loops, deviations in dimensional accuracy within a tolerance range of a few hundredths of a millimeter to a few tenths of a millimeter can occur even before the laser welding process.

[0008] As a result, individual defects in the quality of laser welding connections systematically occur within the large total number of connections in a winding. The qualitative sensitivity of such hairpin winding manufacturing processes leads to a high level of quality control effort, as the laser welding results are visually checked individually, albeit automatically, for each of the numerous connections.

[0009] In summary, these manufacturing processes result in a high rejection rate of windings with inadequate properties, which can be caused, for example, by a single inferior electrical connection among a total of sufficient electrical connections between the conductor sections. It is an object of the invention to create a technology that enables more homogeneous quality of welded joints, shorter production times, and / or lower production costs in the production of windings from preformed conductor sections.

[0010] The above object is achieved by a manufacturing method of an electrically conductive winding with the steps of claim 1 and an electrically conductive winding with the features of claim 16. Further features and details of the invention emerge from the subclaims, the description and the drawings.

[0011] Features and details that are described in connection with the manufacturing method according to the invention naturally also apply in connection with the winding according to the invention and vice versa, so that with regard to the disclosure of the individual aspects of the invention, reference is or can always be made to each other.

[0012] The manufacturing method according to the invention serves to produce an electrically conductive winding according to the invention for a rotating electrical machine, which has a main winding section and at least one winding head section that forms an axial end of the winding. For this purpose, the manufacturing method comprises the following steps:

[0013] Aligning and fixing free conductor ends of the main winding section to a connection plane extending orthogonally with respect to a central axis of the winding between the main winding section and the winding head section;

[0014] Aligning and fixing free conductor ends of the winding head section to the connection plane; so that after alignment and fixing, the conductor ends of the main winding section and the winding head section are opposite each other in pairs at the connection plane;

[0015] Applying axially opposing forces between the main winding section and the winding head section so that the paired, opposite conductor ends come into axial contact under pressure; and moving the main winding section and / or the winding head section in a cyclical relative movement between the main winding section and the winding head section along the connection plane so that the paired, opposite conductor ends are subjected to a pressurized frictional contact until the paired, opposite conductor ends are materially connected by friction-induced heating.

[0016] Likewise, the electrically conductive winding according to the invention for a rotating electrical machine proposes the following structure, which enables a connection of conductor sections by the manufacturing method according to the invention: a main winding section extending coaxially to a central axis of the winding, with an arrangement of conductor elements for electromagnetic interaction in the rotating electrical machine; and at least one winding head section, which forms an axial end of the winding, with an arrangement of curved conductor elements for deflecting a current flow between the conductor elements of the main winding section; wherein conductor ends of the main winding section and conductor ends of the winding head section are each electrically connected to one another by welded joints, for the formation of connected turns of the winding;and wherein the welded joints are arranged in a common connection plane which extends orthogonally with respect to the central axis of the winding between the winding main section and the winding head section;

[0017] The invention thus provides, for the first time, a suitable winding structure and a method for simultaneously connecting all conductor sections of a hairpin winding using a vibration or friction welding joining technique. Likewise, the invention provides, for the first time, a hairpin winding structure in which the conductor elements are not connected to one another at one axial end of the winding, but rather various axial sections of the winding, such as in particular a winding head and a central section, are connected to one another by vibration or friction welding. In this context, the invention finally provides for the first time for free ends of conductor elements to be brought into frictional contact with one another at their ends in order to establish a materially bonded connection while heating the frictional contact.A major advantage of the invention is that a very uniform quality of the welded joint is achieved across all connection points using a vibration or friction welding joining technique. During this uniform welding process, identical movement, intensity and duration ensure that heat is applied evenly across the connecting surfaces, resulting in homogeneous material melting at all connection points. The vibration friction, which heats the conductor ends moving against each other, creates a homogeneous, dough-like mass of conductor material, i.e., molten copper. Once the material structure has cooled, this results in a large effective electrical conductor cross-section due to small defects such as inclusions or blowholes in the weld seam. The low heat input leads to a higher quality welded joint with a more homogeneous material structure and a higher resulting electrical conductivity.A correspondingly lower electrical resistance of these connections ultimately has a positive effect on the overall resistance of the winding.

[0018] A further advantage of the invention is that, compared to other welding methods, such as spot laser welding in particular, the thermal stress on the conductor ends is lower. The lower heat input also reduces the risk of faulty melting of an insulation layer or insulating lacquer layer on the conductors in the connection area.

[0019] Another advantage is that the connections are not located at the apex of hairpin conductor loops, i.e., not at an axial end of the winding, but rather within the axial extension of a winding. This allows the influence of tolerances resulting from forming steps, such as bending at a apex of a conductor loop, or twisting of free ends, on the dimensional accuracy of the positioning of the conductor ends to be connected before the welding process to be avoided or minimized.

[0020] The aforementioned advantages lead to the further advantage that the inventive technology, with regard to the process and winding structure, achieves an improved production rate with lower quality rejects after connecting all conductor sections of a winding. Finally, a particular advantage of the invention is the significantly shorter production time for a winding due to the simultaneous connection of the conductor elements instead of sequential connection. This, in turn, leads to higher throughput in a production line and lower production costs per unit.

[0021] According to one aspect of the invention, the cyclic relative movement can be a concentric oscillation relative to the central axis of the winding, performed at a predetermined frequency or at a variable frequency within a predetermined frequency range. Thus, an easily controlled and uniform range of motion with respect to the radial arrangement of the conductor ends is achieved.

[0022] According to one aspect of the invention, the cyclic relative movement can be an eccentric circular movement relative to the central axis of the winding, performed at a predetermined speed or at a variable speed within a predetermined speed range. Thus, an alternative range of movement is achieved with respect to the radial arrangement of the conductor ends.

[0023] According to one aspect of the invention, an amplitude or stroke of the cyclic relative movement can be smaller than a diameter of a conductor cross-section of a conductor element of the main winding section or the winding head section. This prevents lateral sliding or snagging of the flanks of the pressurized conductor ends.

[0024] According to one aspect of the invention, the cyclic relative movement can be initiated by means of an actuator at only one of the main winding section and the winding head section, while the other of the main winding section and the winding head section is fixed. Thus, it is sufficient to control only one of the two elements of the relative movement by means of actuators for the movement sequence.

[0025] According to one aspect of the invention, the frictional contacts between the opposing conductor ends can be subjected to a predetermined pressure or a variable pressure within a predetermined pressure range during the cyclical relative movement. The pressure can remain constant or be set to vary, e.g., decreasing over the course of the welding process.

[0026] According to one aspect of the invention, the alignment and fixing of the free conductor ends of the main winding section and / or the winding head section can be carried out using at least one fixing element, wherein conductor elements are fixedly received in receiving cavities which are formed in a radial conductor arrangement of the winding in the fixing element which is predetermined with respect to the connection plane.

[0027] According to one aspect of the invention, a step of determining whether the material connection has been achieved can be performed after a predetermined period of cyclic relative movement has elapsed. This provides a simple condition for quality assurance of the welding process.

[0028] According to one aspect of the invention, a step of determining the achievement of the material connection can be carried out as a function of a reaction of the pressure acting on the frictional contact during the cyclic relative movement.

[0029] Thus, a sensor-dependent condition for quality assurance of the welding process is introduced into the process.

[0030] According to one aspect of the invention, the pressure acting on the frictional contact can be obtained by means of a force sensor which detects the applied, axially opposing forces between the winding main section and the winding head section.

[0031] According to one aspect of the invention, a step of determining whether the material connection has been achieved can be performed as a function of an approximately axial relative movement between the main winding section and the winding head section during the cyclic relative movement. Thus, an alternative sensor-dependent condition for quality assurance of the welding process is introduced into the method.

[0032] According to one aspect of the invention, the axially approximate relative movement can be acquired by means of a displacement sensor that detects a distance between axial positions of the main winding section and the winding head section. According to one aspect of the invention, a step of determining whether the material connection has been achieved can be performed depending on a temperature resulting from the frictional heating at the frictional contact between the conductor ends. Thus, an alternative sensor-dependent condition for quality assurance of the welding process is introduced into the method.

[0033] According to one aspect of the invention, the temperature at the friction contact on at least one opposing pair of conductor ends can be detected by a non-contact temperature sensor. This allows for simple temperature detection.

[0034] According to one aspect of the invention, a step of maintaining the application of the axially opposing forces to the main winding section and the winding head section can be performed for a predetermined period of time, even after the material connection has been determined and the cyclic relative movement has been stopped. Thus, material-specific properties can be incorporated into the adjustment of the connection technology.

[0035] According to one aspect of the invention, the welded joint can be characterized by a homogeneous material structure of a conductor material by means of friction welding and / or vibration welding. Thus, a simultaneous connection and a consistent connection quality can be achieved on all conductor elements.

[0036] According to one aspect of the invention, the conductor ends of the main winding section and the winding head section, which are connected by means of the welded joints, can be aligned orthogonally to the connection plane. Thus, the conductor ends can be optimally heated and connected by the movement sequence of the connection technology.

[0037] According to one aspect of the invention, the conductor elements of the winding head section can be designed as hairpin conductor elements whose shape is prefabricated according to the same predetermined curvature. This ensures a large number of similar parts and a high packing density of electrical conductors relative to the installation space.

[0038] According to one aspect of the invention, the conductor elements of the main winding section can extend axially to the central axis of the winding. This enables a simple structure and assembly of the conductor elements. According to one aspect of the invention, the conductor elements of the main winding section and the winding head section can have the same, preferably prismatic, conductor cross-section, at least in the region of their connected conductor ends. This ensures a high packing density of the electrical conductors relative to the installation space.

[0039] According to one aspect of the invention, at least one electrically insulated fixing element can be arranged on the winding in a region axially adjacent to the connection plane; wherein the at least one fixing element has receiving cavities formed in a radial conductor arrangement of the winding predetermined with respect to the connection plane, and wherein the conductor elements of the main winding section and / or the conductor elements of the winding head section are fixedly received in the receiving cavities, positioned in accordance with the conductor arrangement of the winding. This ensures positioning and support of the free conductor ends against deformation before and during the connection process.

[0040] According to one aspect of the invention, a first fixing element can be arranged on the main winding section, in which the conductor elements are fixedly received, and a second fixing element can be arranged on the winding head section, in which the conductor elements are fixedly received, wherein the first fixing element and the second fixing element are opposite one another with respect to the connection plane. This ensures the best possible fixation, alignment, and support of the conductor ends before and during the connection process.

[0041] According to one aspect of the invention, the at least one fixing element can be made of an electrically insulating plastic. This allows molded parts for the fixing element to be manufactured more easily by injection molding.

[0042] According to one aspect of the invention, the plastic can be a thermoplastic, preferably PEEK. This material can also perform an insulating function after deformation in the event of significant heating.

[0043] According to one aspect of the invention, a plastic-molded insulation section can be arranged at one axial end of the winding head section, which encloses the conductor elements toward one axial end of the winding head section. Thus, the rotor winding is insulated from stationary machine parts and protected from the ingress of dirt or other foreign matter.

[0044] According to one aspect of the invention, the second fixing element and the overmolded insulation section of the winding head section can be formed integrally. For example, they can be connected after the sections of the winding are connected at their circumferential surface, so that the winding head is encapsulated.

[0045] According to one aspect of the invention, the winding can comprise two winding head sections on both axial sides of the main winding section. Thus, the same conductor elements and the same connection technology can be used on both sides of the winding.

[0046] According to one aspect of the invention, at least one sensor can be arranged on the winding head section. This sensor can be easily positioned in a preceding step of assembling the winding head, or possibly in conjunction with the insulation section. Furthermore, the sensor is exposed to a comparatively low heat input during the joining process. In conventional welding processes, a sensor on the winding head would be damaged by the high heat input.

[0047] According to one aspect of the invention, a sensitive section of the sensor can be arranged in the region of the connection plane between the main winding section and the winding head section. The sensor, such as a temperature sensor, could also be connected to the conductor elements using the same step for connecting the winding sections, thus eliminating the need for an additional step for connecting the sensor.

[0048] Further advantages, features, and details of the invention will become apparent from the following description, which describes an embodiment in detail with reference to the drawings. They show schematically:

[0049] Fig. 1 is a perspective view of separate sections of a winding and a machine element; Fig. 2 is a perspective view of the sections of the winding with additional components and the machine element;

[0050] Fig. 3 shows an assembled state before connecting the sections of the winding in perspective view;

[0051] Fig. 4 shows a movement sequence of the connection technology in perspective view; and

[0052] Fig. 5 a finished product consisting of the winding, the other components and the machine element in perspective view.

[0053] Fig. 1 shows an assembly with individual axial sections of an electrically conductive winding 100 for a rotating electrical machine, such as an electric motor or a generator. The winding 100 is designed to match a machine element of the rotating electrical machine, such as a rotor or, as in the presently illustrated embodiment, a stator 200, to which the winding 100 is assembled.

[0054] The winding 100 comprises, in a central part, a main winding section 10 made of substantially straight, axially extending conductor elements 11, which are distributed in a radial arrangement around a central axis M of the winding 100. During assembly of the winding 100, the conductor elements 11 of the main winding section 10 are received in slots provided with an axial extension in the stator 200 according to the number and radial position, after which conductor ends 12 of the conductor elements 11 of the main winding section 10 protrude exposed from end faces of the stator 200.

[0055] The winding 100 comprises a winding head section 20 made of curved conductor elements 22 at both axial ends. The curved conductor elements 22 of the winding head sections 20 are positioned in a radial arrangement corresponding to the conductor elements 11 of the main winding section 10, each extend with a tangential inclination to the central axis M, and are each designed in the form of a turning section. Each conductor element 22 of the winding head section 20 has two conductor ends 21, both of which are aligned with the main winding section 10, wherein one of the conductor ends 21 of the conductor elements 22 of the winding section 20 is assigned to a conductor end 12 of a conductor element 11 of the main winding section 10 in a radial arrangement. Correspondingly assigned pairs of conductor ends 21 of the winding head sections 10 and conductor ends 12 of the main winding section 10 are located in the illustration in Fig.1 in relation to a connecting plane V. The connecting planes V each run orthogonally to the central axis M between the mutually facing end faces of the winding head sections 20 and the main winding section 10.

[0056] After connecting the individual sections of the winding 100, which in the present embodiment is a stator winding, they perform the following functions. The main winding section 10 of the winding 100 generates electromagnetic fields when a switched or induced current flows through the axially extending conductor elements 11. These fields interact with other electromagnetic fields from a stator winding of the rotating electrical machine. This generates a rotational force or a current flow in the rotating electrical machine, depending on the application. The winding head sections 20 close individual turns of the winding 100, with each of the curved conductor elements 12 of the winding head sections 20 redirecting a current flow between two of the conductor elements 11 of the main winding section 10 in opposite axial directions.

[0057] In addition to Fig. 1, Fig. 2 shows further auxiliary components useful for the connection technology, which remain as part of the winding 100 after the sections have been connected. An annular, first fixing element 41 with receiving cavities 44 is arranged on each end face of the stator 200. The receiving cavities 44 have essentially the same radial arrangement and structure as the grooves of the stator 200 in order to receive the conductor sections 11 in the region of the conductor ends 12 to be connected, which protrude from the stator 200, and to fix them in position for the connection technology and to support them against deformation.

[0058] Complementary to this, a similar, annular, second fixing element 42 with receiving cavities 44 is arranged on the inward-facing end faces of the winding head sections 20. These receiving cavities 44 also have essentially the same radial arrangement and structure as those of the first fixing element 41 in order to receive the curved conductor sections 22 in the region of the conductor ends 21 to be connected, with corresponding assignment to the conductor ends 12 of the conductor sections 11 to be connected. Thus, in the same way, the second fixing element 42 fixes the curved conductor sections 22 protruding axially from the winding head section 20 in a precise position in the region of the conductor ends 21 and supports them against deformation during the connection process. The first fixing elements 41 and the second fixing elements 42 are located opposite one another concentrically to the central axis M with respect to the connection planes V.Furthermore, an insulating section 50 is arranged at each of the axial ends of the winding 100, which covers and insulates the winding head section 20 from the outside. The first fixing elements 41, the second fixing elements 42, and the insulating sections 50 are formed from an electrically insulating material, in particular a thermoplastic, such as preferably PEEK. This material has the advantage that, in the event of heating and possibly deformation during the connection process, it remains intact as an insulating element around the conductor elements 11, 22 and maintains an insulating function.

[0059] Fig. 3 shows, with the exception of the second fixing elements 42 and the insulation sections 50, the previously described sections and auxiliary components of the winding 100 as well as the stator 200 of the rotating electrical machine in an assembled state before the connection technology for connecting the sections of the winding 100 is carried out. In this state, the associated pairs of conductor ends 12 of the main winding section and the conductor ends 21 of the winding head sections 20 are aligned congruently with each other at the connection plane V, so that they can be brought into contact with each other at the end face under axial pressure.

[0060] Fig. 4 illustrates a movement sequence of the connection technology. In the illustrated embodiment, vibration welding is carried out with a rotary vibration movement. One of the winding head sections 20 and the main winding section 10 are constantly subjected to a force K in the axial direction, whereby the paired conductor ends 12, 21 to be connected are in contact under pressure at the end faces. At the same time, a concentric oscillation S is carried out in a relative movement between the winding head section 20 and the main winding section 10 with respect to the central axis M. An amplitude A of the concentric oscillation S of the relative movement is preferably at most as large as a corresponding concentric dimension of a pair of associated conductor elements 11, 22 in order to prevent mutual lateral sliding of the end faces and snagging of the flanks of the free conductor ends 12, 21.

[0061] The vibration welding process lasts a few seconds, i.e., in particular, less than 5 seconds, until the end faces of the free conductor ends 12, 21 in frictional contact have heated up to a temperature of a material melting point of the copper-based conductor material and a common material melt of a welded joint has been formed between the conductor elements 11, 22. After this point in time, the movement sequence is stopped and the axial force K is maintained unchanged or decreasing, while the welded joint cools down again in the form of a newly formed, homogeneous material structure between the previously free conductor ends 12, 21. Due to the high thermal conductivity of the conductor material, which contributes to high heat dissipation from the welded joint, the cooling phase also lasts only a few seconds.

[0062] In an alternative embodiment not shown in detail, an eccentric movement sequence takes place in the connection technology. A winding head section 20 and the main winding section 10 are also subjected to a constant force K in the axial direction, whereby the paired conductor ends 12, 21 to be connected are in contact under pressure at the end faces. At the same time, an eccentric circular movement is performed in a relative movement between the winding head section 20 and the main winding section 10 with respect to the central axis M. The stroke of the eccentric relative movement is preferably so small that mutual entanglement of the flanks of the free conductor ends 12, 21 is avoided.

[0063] Fig. 5 shows the product of an assembly of a motor rotor 200, ready for installation in a rotating electrical machine, which is assembled with the winding 100. To obtain the illustrated product, the individual sections of the winding 100 were positioned relative to one another, fixed, and simultaneously connected to one another using the previously described joining technique, i.e., in particular, by a form of vibration welding or friction welding of all preformed conductor sections 11, 22. Subsequently, the insulation sections 50 were joined to the assembly so that the axial ends of the winding 100 accommodated in the stator 200, with the exception of protruding connecting conductor ends, are insulatingly covered and protected.

[0064] The above explanations of the embodiments describe the present invention exclusively by way of examples. Of course, individual features of the embodiments can be freely combined with one another, provided they are technically feasible, without departing from the scope of the present invention.

[0065] List of reference symbols

[0066] 10 Main winding section

[0067] 11 Conductor elements of the main winding section

[0068] 12 conductor ends of the main winding section

[0069] 20 winding head section

[0070] 21 conductor ends of the winding head section

[0071] 22 conductor elements of the winding head section

[0072] 41 first fixation element

[0073] 42 second fixing element

[0074] 44 receiving cavities

[0075] 50 insulation section

[0076] 100 windings

[0077] 200 stator

[0078] A Amplitude of the concentric oscillation

[0079] K axially opposing forces

[0080] M Central axis of the winding

[0081] S concentric oscillation

[0082] V Connection level

Claims

Patent claims 1 . Manufacturing method of an electrically conductive winding (100) for a rotating electrical machine, comprising a winding main section (10) and at least one winding head section (20) forming an axial end of the winding (100), comprising the steps: - aligning and fixing free conductor ends (12) of the main winding section (10) to a connecting plane (V) which extends orthogonally with respect to a central axis (M) of the winding (100) between the main winding section (10) and the winding head section (20); - Aligning and fixing free conductor ends (21) of the winding head section (20) to the connecting plane (V); so that after alignment and fixing, the conductor ends (12, 21) of the main winding section (10) and of the winding head section (20) are located opposite each other in pairs at the connecting plane (V); - applying axially opposing forces (K) between the main winding section (10) and the winding head section (20), so that the opposite conductor ends (12, 21) assigned in pairs come into axial contact under pressure; and - Moving the main winding section (10) and / or the winding head section (20) in a cyclical relative movement between the main winding section (10) and the winding head section (20) along the connection plane (V), so that the paired, opposite conductor ends (12, 21) are subjected to a pressurized frictional contact until the paired, opposite conductor ends (12, 21) are materially connected by friction-induced heating.

2. Manufacturing method according to claim 1, wherein the cyclic relative movement is a concentric oscillation (S) with respect to the central axis (M) of the Winding (100) which is carried out at a predetermined frequency or at a variable frequency with a course in a predetermined frequency range.

3. Manufacturing method according to claim 1, wherein the cyclic relative movement is an eccentric circular movement with respect to the central axis (M) of the winding (100), which is carried out at a predetermined speed or at a variable speed with a course in a predetermined speed range.

4. Manufacturing method according to claim 2 or 3, wherein an amplitude (A) or a stroke of the cyclic relative movement is smaller than a diameter of a conductor cross-section of a conductor element of the winding main section (10) or the winding head section (20).

5. Manufacturing method according to one of the preceding claims, wherein the cyclic relative movement is initiated only at one of the winding main section (10) and the winding head section (20) by means of an actuator, while the other of the winding main section (10) and the winding head section (20) is fixed in a stationary manner.

6. Manufacturing method according to one of the preceding claims, wherein the frictional contacts between the opposite conductor ends (12, 21) are subjected to a predetermined pressure or a variable pressure with a course in a predetermined pressure range during the cyclic relative movement.

7. Manufacturing method according to one of the preceding claims, wherein the alignment and fixing of the free conductor ends (12, 21) of the main winding section (10) and / or of the winding head section (20) is carried out using at least one fixing element (41, 42), wherein conductor elements are fixedly received in receiving cavities (44) which are formed in a radial conductor arrangement of the winding (100) in relation to the connection plane (V) in the fixing element (41, 42).

8. Manufacturing method according to one of the preceding claims, comprising the step: - Determining whether the material connection has been achieved after a predetermined period of cyclic relative movement.

9. Manufacturing method according to one of the preceding claims, comprising the step: - Determining the achievement of the material connection as a function of a reaction of the pressure acting on the frictional contact during the cyclic relative movement.

10. Manufacturing method according to claim 9, wherein the pressure applying the frictional contact is obtained by means of a force sensor which detects the applied, axially opposing forces (K) between the winding main section (10) and the winding head section (20).

11. Manufacturing method according to one of the preceding claims, comprising the step: - Determining the achievement of the material connection as a function of an approximate axial relative movement between the main winding section (10) and the winding head section (20) during the cyclic relative movement.

12. Manufacturing method according to claim 11, wherein the axially approximate relative movement is obtained by means of a displacement sensor which detects a distance between axial positions of the winding main section (10) and the winding head section (20).

13. Manufacturing method according to one of the preceding claims, comprising the step: - Determining the achievement of the material connection as a function of a temperature resulting from the friction-induced heating at the frictional contact between the conductor ends (12, 21).

14. Manufacturing method according to claim 13, wherein the temperature at the frictional contact on at least one opposite pair of conductor ends (12, 21) is detected by a non-contact temperature sensor.

15. Manufacturing method according to one of the preceding claims, comprising the step: - Maintaining the application of the axially opposing forces (K) to the main winding section (10) and the winding head section (20) over a predetermined period of time after the material connection has been determined and the cyclic relative movement has been stopped.

16. An electrically conductive winding (100) for a rotating electrical machine, which is manufactured by the method steps of the manufacturing method according to one of claims 1 to 15, comprising: a winding main section (10) extending coaxially to a central axis (M) of the winding (100), with an arrangement of conductor elements (11) for electromagnetic interaction in the rotating electrical machine; and at least one winding head section (20), which forms an axial end of the winding (100), with an arrangement of curved conductor elements (22) for deflecting a current flow between the conductor elements (11) of the winding main section (10); wherein Conductor ends (12) of the main winding section (10) and conductor ends (21) of the winding head section (20) are each electrically connected to one another by welded joints, for forming connected turns of the winding (100); and wherein the welded joints are arranged in a common connection plane (V) which extends orthogonally to the central axis (M) of the winding (100) between the main winding section (10) and the winding head section (20).

17. Electrically conductive winding (100) according to claim 16, wherein the welded joints are characterized by a homogeneous material structure of a conductor material by means of friction welding and / or vibration welding.

18. Electrically conductive winding (100) according to claim 16 or 17, wherein the conductor ends (12, 21) of the winding main section (10) and of the winding head section (20) connected by means of the welded joints are aligned orthogonally to the connection plane (V).

19. Electrically conductive winding (100) according to one of claims 16 to 18, wherein the conductor elements (22) of the winding head section (20) are designed as hairpin conductor elements, the shape of which is prefabricated according to the same predetermined curvature.

20. Electrically conductive winding (100) according to one of claims 16 to 19, wherein the conductor elements (11) of the winding main section (10) extend axially to the central axis (M) of the winding (100).

21. Electrically conductive winding (100) according to one of claims 16 to 20, wherein the conductor elements (11, 22) of the main winding section (10) and of the winding head section (20) have the same, preferably prismatic, conductor cross-section at least in the region of their connected conductor ends (12, 21).

22. Electrically conductive winding (100) according to one of claims 16 to 21, wherein at least one electrically insulated fixing element (41, 42) is arranged on the winding (100) in a region axially adjacent to the connecting plane (V); wherein the at least one fixing element (41, 42) has receiving cavities (44) which are formed in a radial conductor arrangement of the winding (100) predetermined in relation to the connecting plane (V), and wherein the conductor elements (11) of the main winding section (10) and / or the conductor elements (22) of the winding head section (20) are positioned in correspondence with the conductor arrangement of the winding (100) and are fixedly received in the receiving cavities (44).

23. Electrically conductive winding (100) according to claim 22, wherein a first fixing element (41) is arranged on the winding main section (10), in which the conductor elements (11) thereof are fixedly received, and a second fixing element (42) is arranged on the winding head section (20), in which the conductor elements (22) thereof are fixedly received, wherein the first fixing element (41) and the second fixing element (42) are opposite one another with respect to the connecting plane (V).

24. Electrically conductive winding (100) according to one of claims 22 or 23, wherein the at least one fixing element (41, 42) is formed from an electrically insulating plastic.

25. Electrically conductive winding (100) according to one of claims 22 to 24, wherein the plastic is a thermoplastic, preferably PEEK.

26. Electrically conductive winding (100) according to one of claims 22 to 25, wherein an insulating section (50) overmolded from plastic is arranged at an axial end of the winding head section (20), which encloses the conductor elements (22) towards an axial end of the winding head section (20).

27. Electrically conductive winding (100) according to claim 26, wherein the second fixing element (42) and the overmolded insulation section (50) of the winding head section (20) are integrally formed.

28. Electrically conductive winding (100) according to one of claims 16 to 27, wherein the winding (100) comprises two winding head sections (20) on both axial sides of the winding main section (10).

29. Electrically conductive winding (100) according to one of claims 16 to 28, wherein at least one sensor is arranged on the winding head section (20).

30. Electrically conductive winding (100) according to claim 29, wherein a sensitive portion of the sensor is arranged in the region of the connection plane (V) between the winding main portion (10) and the winding head portion (20).

31. Electrically conductive winding (100) according to one of claims 16 to 30, which is produced by the method steps of the manufacturing method according to one of claims 1 to 15.

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