Cable segment for a winding of an electrical machine and a manufacturing method for a cable segment

Description

[0001] The present invention relates to a conductor segment for a winding of an electrical machine, wherein the conductor segment is constructed from at least two metallically conductive sections, a braided wire and a flat wire. Furthermore, the present invention relates to a method for producing a conductor segment for a winding of an electrical machine, wherein a braided wire is combined with a flat wire. The present invention also relates to a motor vehicle with a drive train.

[0002] In other words, the present invention relates to a line segment according to the preamble of claim 1, a method for producing a line segment according to the preamble of claim 17 and a motor vehicle according to the preamble of claim 24. Technical field

[0003] An electric machine for generating torque for a vehicle drive is usually constructed as an arrangement of a rotor and an outer stator, between which there is an air gap. To simplify production, "windings" are not created by winding individual wires into coils, but rather the coils are formed from multiple wire elements composed of so-called field coil segments. The coils generate the fields for driving the rotor, as described, for example, in DE 10 2012 212 870 B4 (owner: GM Global Technology Operations LLC; patent publication date: October 14, 2021). The stator is therefore a circular device that has a plurality of radially aligned slots with coil windings located therein and is arranged concentrically to a rotational axis of the rotor. The coil arrangement can be, for example,A stator with three phases and three poles can have nine pairs of opposing field coils, each of which can be realized with wire elements of different sizes. The stator serves to generate a dynamic magnetic field for the operation of an electrical machine. For the rotors, both arrangements with field coil segments and arrangements equipped with circumferentially distributed permanent magnets are considered depending on the application.

[0004] The formation of stator windings using conductor wires with a covering insulation layer, which are inserted into the stator slot, is described, for example, in DE 102011 000 172 A1 (applicant: Denso Corp.; disclosure date: September 22, 2011). The windings are formed using U-shaped conductor wire segments, which are intended to have a rectangular cross-section. Two sections of these segments are arranged in slots. The conductor wires are to be welded together at the overlapping end sections of the segments, which are bent radially outward.

[0005] The electric motors can be used in various motor-transmission arrangements of motor vehicles. Some examples of such arrangements are described in patent application DE 10 2021 123 019 A1 (applicant: hofer powertrain innovation GmbH; disclosure date: March 10, 2022). Accordingly, a powertrain can also comprise two electric motors, two inverters, and two transmissions, each of which can be housed in sub-housings. Such an arrangement in an overall housing is also referred to as a drive block. State of the art

[0006] According to DE 10 2016 123 067 A1 (applicant: Porsche AG; disclosure date: May 30, 2018), a stator with windings is to be formed from bar segments, with four bar segments arranged in each slot. A first group of series-connected bar segments is to have a smaller cross-section than a second group of series-connected bar segments.

[0007] According to DE 10 2007 021 321 A1 (applicant: Siemens AG; disclosure date: November 13, 2008), so-called busbars can be used to connect coils. In a stator with multiple coils, the coils should be interconnected on one side of the stator. The ends of the coils should be crimped or welded to the ends of busbars. The authors of DE 10 2007 021 321 A1 hope to improve automated production. The busbars should preferably be stamped from a single sheet of metal. In their central area, the busbars should have insulation, which can be in the form of a sprayed sheath. Stranded wires or solid copper wire can also be used as busbars. Busbars can be curved and arranged next to one another in a radial direction.

[0008] DE 11 2019 006 919 T5 (applicant: Mitsubishi Electronic Corporation; publication date of the German translation: November 11, 2021) and US 9 419 491 B2 (owner: Hitachi Metals Ltd.; publication date: August 16, 2016) deal, among other things, with connections for the stator.

[0009] According to DE 10 2014 214 066 A1 (applicant: Volkswagen Aktiengesellschaft; disclosure date: January 21, 2016), the connecting conductors of a head end of the stator are to be cast in a casting frame after the contacting with an insulating material, such as a casting resin, in such a way that only external connections of the connecting conductors lead out.

[0010] EP 3 512 075 B1 (owner: Toyota Jidosha Kabushiki Kaisha; patent publication date: October 13, 2021) discloses a stator structure in which the coil windings are composed of U-shaped or chevron-shaped segments and are designed with a substantially rectangular cross-section. Two segments are to be coupled together with a connector. It is proposed to establish the connection by inserting them into fittings and crimping them. This is intended to eliminate the need for welding. The connector can be coated with an insulating film on its outer surfaces. Furthermore, according to one embodiment, the body of the connector can be tubular, with an elastic or fluid conductor located inside. This is intended to enable flexibility in an axial direction. Flexible wires, referred to as "flexible round wires," are considered as coil materials.

[0011] US 6,353,198 B1 (Owner: General Electric Company; publication date: March 5, 2002) deals with welding bundles of flat wires for a stator winding using a U-shaped bridge into which the ends of the bundles are inserted.

[0012] Further bar conductor arrangements for stators are described, for example, in WO 2020 / 092 570 A1 (applicant: North Carolina State University; publication date: May 7, 2020) and in DE 10 2020 130 647 A1 (applicant: Grob GmbH; disclosure date: January 7, 2021). According to DE 10 2020 130 647 A1, bar conductors are to be formed from individual wire segments because stranded wires have proven to be disadvantageous in the manufacture of the stator.

[0013] Nevertheless, some developers do not consider these supposed disadvantages as an exclusion criterion for the use of stranded wires in the construction of a stator.

[0014] US 2012 / 0 212 088 A1 (applicant: Innovative Energy, Inc.; publication date: August 23, 2012) describes conductor bars in the form of strands that extend linearly in the longitudinal direction of the stator's rotation axis. Connectors are welded to both ends of the strands. The connectors are intended to extend as arcs over slightly more than 90° of the stator's curvature and be arranged in different planes.

[0015] A winding cable for a stator consisting of a bundle of nine individual wires is described in DE 10 2004 050 824 A1 (applicant: Kabushiki Kaisha Toyota Jidoshokki; disclosure date: May 25, 2005). Depending on the shape of the stator slot, the wires can be arranged in a square or trapezoidal pattern. An insulating coating on the cable is intended to eliminate the need to insert insulating paper into each slot. The cable is intended to be bent at predetermined intervals to form a waveform. Different cables in a coil head between two different slots are to be connected by soldering. It is also proposed to combine groups of the conductor wires to form a coil. However, it is questionable whether several individual wires arranged side by side can correctly be referred to as a single stranded wire.

[0016] As is clear from WO 2015 / 162 586 A2 (applicant: Brusa Elektronik AG; publication date: October 29, 2015), stranded wires can achieve a shape that is stable against twisting during bending by mechanically connecting the individual wires along their length. Furthermore, the ends of the stranded wires can be enclosed by sleeves. The cross-sections of a straight, shaped stranded wire in the longitudinal direction should be congruent over its entire length. According to an embodiment described in Figure 2As shown, the cross-sectional shape of a preformed strand is intended to correspond to the trapezoidal shape of a stator slot. In a rolling mill, a strand with a round cross-section is intended to be able to be formed into the desired rectangular or trapezoidal shape. To facilitate the insertion of one end of the preformed strand into the stator slot, WO 2015 / 162 586 A2 proposes forming pointed ends on the preformed strands. After insertion, a bending process can be performed on the preformed strands. The ends of the preformed strands can also be covered with sleeves, according to EP 3 051 669 B1 (owner: Brusa Elektronik AG; publication date: August 22, 2018).

[0017] A method for converting coil windings from a round stranded wire cross-section into a trapezoidal shape is described in EP 2 991 199 A1 (applicant: Mitsubishi Electric Corporation; publication date: March 2, 2016). In this method, several stranded wires arranged one above the other, each with a round cross-section, are pressed into a conically tapered mold using a die. The conductors are then removed from the mold.

[0018] A stator according to DE 102018 131 965 A1 (applicant: ThyssenKrupp AG; disclosure date: June 18, 2020) has a plurality of bar conductors and a plurality of interconnection webs. The bar conductors can be designed as so-called "hairpins" or I-shaped (so-called "I-pins"). Compression-molded and twisted wire strands can also be used as bar conductors. The bar conductors are arranged in bar conductor groups, and the bar conductors are to be connected via interconnection web groups, which are to be arranged in interconnection levels on both sides of the stator. DE 10 2018 131 965 A1 also proposes that the height and width of the interconnection webs differ by a factor of the order of 1.5. In other published applications by the same applicant, e.g. B. in DE 10 2017 125 887 A1 (disclosure date: 09.05.2019), in DE 10 2018 208 407 A1 (disclosure date: 28.11.2019) and DE 10 2018 131 960 A1 (publication date: June 18, 2020) describe methods and devices for manufacturing stranded wires and electrical machines or their stators. According to DE 10 2018 218 732 A1 (publication date: April 30, 2020), special sections at the head ends of the stranded wires can also serve as heat exchanger sections. DE 10 2017 125 887 A1 recommends manufacturing stranded wires from individual wires insulated with lacquer, whereby the insulating layers on the individual wires are individually removed along a partial length required for further contacting, e.g., by laser evaporation. A sleeve is then pushed over the stripped ends of a stranded wire, enabling contact between the individual wires. Formed strands produced in this way are intended to open up possibilities for reducing the installation space in the area of ​​the head end of a stator winding.

[0019] WO 2021 / 250 259 A1 (applicant: Jaguar Land Rover Ltd.; publication date: December 16, 2021) describes a permanent magnet synchronous motor whose rotor is said to have eight rotor poles. A cylindrical stator with radially extending slots serves to accommodate windings, with the winding conductors, e.g., pressed into a rectangular shape, being arranged radially next to one another in the slots. A combination of stranded wires and wires with a single core, as well as a combination of axial and radial insertion into such a slot, are considered advantageous stator designs. The coil wire is said to be formed from a shaped strand, which may have a U-shape, also referred to as a "hairpin." The segments can be connected to one another by welding or crimping.Each slot should contain several main and several secondary conductors, which differ in radial direction due to their dimensions and are connected to different coils, also known as a "dual winding configuration." These coils can be connected to one or two inverters in various configurations for motor operation.

[0020] In addition, there are other publications in the intellectual property literature that deal with stator windings.

[0021] US 2021 / 0 006 115 A1 (applicant: GM Global Technology Operations LLC; publication date: January 7, 2021) aims to design so-called "hairpin"-type conductors in such a way that the conductor portion through which approximately 63% of the alternating current to be conducted flows due to the "skin effect" occurring with alternating currents has a greater depth than the thickness of the individual strands of the conductor. The strands are therefore to be made of thinner wires compared to the section of the conductor to which most of the conduction current is attributed due to the "skin effect." Several embodiments of a conductor with thicker and thinner strands are shown in sectional views at the end of the figure. However, the stranded wire is only partially energized, because the "skin effect" allows the current to continue to flow primarily in the outer portion of the stranded wire.

[0022] DE 10 2005 025 217 A1 (applicant: Denso Corp.; disclosure date: December 22, 2005) deals with the topic of "ohmic resistance of a stator winding" and aims to reduce resistance by arranging differently designed U-conductor segments in a stator, which together become parts of the stator windings. The U-conductor segments are designed like brackets. In this way, the lengths of the bridging sections from the first conductor segments to the second conductor segments can be shortened. In other words, such a motor requires a whole series of different U-conductor segments, so that production advantages resulting from a high number of identical parts are unlikely to be realized.

[0023] DE 603 ​​06 850 T2 (owner: Denso Corp.; published on September 6, 2007) deals with a stator winding whose windings are composed of segments. This is intended to improve insulation in the area of ​​the winding ends.

[0024] DE 10 2018 101 231 A1 (applicant: Brusa Elektronik AG; disclosure date: July 25, 2019) describes a motor winding in a stator in which preformed strands are arranged in the longitudinal slots of the stator, but the electrically conductive connecting elements are to be joined to the preformed strands from one end of a preformed strand to the other end of another preformed strand. The actual implementation of the manufacturing technology discussed in DE 10 2018 101 231 A1 is likely to be difficult, or at least require large winding heads, because the preformed strands must protrude sufficiently far from the slots to enable joining techniques such as welding or soldering.

[0025] The two US patents US 5,787,567 A (patent owner: Toyota Jidosha Kabushiki Kaisha; grant date: August 4, 1998) and US 10,128,728 B2 (patent owner: Toyota Jidosha Kabushiki Kaisha; grant date: November 13, 2018) deal with windings and winding materials. US 5,787,567 A is good evidence that at the end of the 1990s, preformed strands were not yet commonly used in the construction of electric motors for motor vehicles, but rather only stranded wires were used for windings. US 10,128,728 B2 also advises against excessively compressing the "parallel portions" in a segmented motor winding. According to US 10 128 728 B2, it is important to shape the thicknesses of a right-hand winding section and a left-hand winding section as closely as possible to the design of the parallel section arranged between them.

[0026] However, because the power class to which a vehicle drive motor belongs requires a minimum amount of copper for the motor currents of the corresponding power class, the windings presented above result in winding heads of a certain size. Task

[0027] However, electromobility regularly requires the most compact and powerful electric machines possible. With particular attention to a good fill factor for the conductor material of the stator windings, as well as the best possible electrical connections and good electrical conduction of the stator winding, it is desirable to ensure high reproducibility in the manufacture of high-quality electric machine components for large-scale production based on the electric machine design. Description of the invention

[0028] The object of the invention is achieved by a line segment according to claim 1; a suitable method for producing a line segment for a winding of an electrical machine can be found in claim 17. A motor vehicle with such a line element is disclosed in claim 24. Advantageous further developments can be found in the dependent claims.

[0029] A conductor segment is preferably used to produce a winding of an electrical machine. It has multiple sections. The conductor segment is constructed from metallically conductive segments, several of which can be distinguished as sections of the conductor segment. The conductor segment can also be referred to as subsegments. A first section or subsegment is a shaped strand. The first section is a shaped strand. Two flat wires are added as further sections. A second and third section are each a flat wire. The flat wires and the shaped strand are electrically conductively connected to one another, e.g., by a diffusion welding process. In other words, there is a single, continuous electrical conductor which, in the preferred embodiment, consists of at least three sections.

[0030] A joint connects the preformed strand and flat wires. To do this, each end, also called the end region, of the preformed strand is joined to one end, also called the end region, of the respective flat wire.

[0031] Preferably, the end regions of the formed strand and the respective end regions of the flat wires joined to them overlap over a certain distance to enable a good joint. The end regions lie on top of one another in the overlap region. In the particularly preferred embodiment, this overlap region is pressed together.

[0032] Further preferred embodiments provide for brazing solder to be introduced, e.g., inserted or inserted, between the end regions of the braided wire and the flat wires that lie one above the other. The brazing solder is melted during the joining process or, if provided, during the pressing process and ensures a particularly good mechanical connection. Furthermore, it has been shown that the brazing solder, depending on the selected composition, also improves electrical conductivity.

[0033] Yet another preferred embodiment provides for a sheathing with a conductive foil or tape, particularly preferably copper foil or copper tape, of those sections of the cable segment according to the invention in which the preformed strand and the associated flat wire overlap. This further improves both the mechanical strength and the electrical conductivity of the cable segment.

[0034] The formed strand is formed from several individual wires twisted together. The flat wire can be a ribbon wire. The formed strand preferably has a first compression-molded end region. In this compression-molded end region, the formed strand has been compacted. Individual wires of the formed strand are preferably arranged particularly densely in the end region. The formed strand can also be referred to as a compaction segment or compaction sub-segment. The compaction segment is overlapped by a flat wire end region. It can also be said that the compaction segment is formed by laterally pressing the flat wire end region onto the formed strand or onto a formed strand end region.

[0035] In a preferred embodiment, the preformed stranded wire and the flat wire are arranged at a line segment angle to each other. The transition between the preformed stranded wire and the flat wire occurs at an angle that is defined within an angular range of 180° to 100°, preferably 180° to 150°, and even more preferably approximately 180°. In other words, the preformed stranded wire and the two flat wires are aligned in a straight line with each other and together form more or less a straight line.

[0036] The preformed stranded wire and the flat wire are firmly bonded together. The bond exhibits electrical conductivity. In other words, current can flow with virtually no resistance from the preformed stranded wire to the flat wire, or from the flat wire to the preformed stranded wire (e.g., when alternating current is applied).

[0037] The production of a cable segment is based on the combination of a preformed strand with at least one flat wire. A first end region of the preformed strand is arranged on a first flat wire end region, whereby an intermediate layer of brazing solder can be inserted between the two end regions. This can then also be referred to as the formation of a three-layer system. The preformed strand and flat wire are aligned or arranged with a cable segment angle to one another. To compact the first end region of the preformed strand and the first flat wire end region as well as the brazing solder, i.e. to the three-layer system, a pressing pressure is applied simultaneously, and brazing solder fusion heat is applied. During joining, the brazing solder fusion heat can be introduced, for example, by diffusion welding. With sufficient heat, the brazing solder melts and spreads, filling any gaps that may exist, e.g., between individual wires.A predetermined transition connection between the shaped strand and the flat wire is created with the selected transition angle.

[0038] By melting the brazing solder, both the flat wire is wetted with brazing solder throughout the flat wire end region, and the preformed strand is impregnated with brazing solder in the end region of the preformed strand. It is particularly advantageous if the surface area of ​​the brazing solder is equal to the surface area of ​​a preformed strand contact area and the surface area of ​​a flat wire end contact area.

[0039] With the aid of the advantageous line segment or a plurality of advantageous line segments, a winding of an electrical machine can be formed which, for example, due to its compactness, enables a space-efficient construction of a drive train which, when installed in a motor vehicle, allows for the release of installation space for other components or can also simplify the production of the motor vehicle by facilitating component assembly.

[0040] Further advantageous embodiments and developments are set out below, which, viewed individually or in combination, may also reveal inventive aspects.

[0041] It is particularly advantageous for the conductivity of the formed stranded wire if all the stranded wires of the formed stranded wire extend from a first end of the cable segment into the flat wire end area. Each stranded wire can be individually coated with an insulating wire enamel layer. This means that each individual conductor is a separate current conductor. The insulating layer of outer individual conductors also protects against short circuits. A double layer of enamel on each individual wire or stranded wire is very advantageous. In a double layer, a wire enamel layer can be coated with an outer layer of a baked enamel. The double layer preferably makes up less than 10% of a stranded wire diameter. The total diameter of the stranded wire preferably has a value that lies in a range of 0.3 mm to 1.2 mm.

[0042] The stranded wires twisted together to form the stranded wire have a lay length. The lay length indicates the distance after which the wound stranded wires return to their original position. In other words, the lay length of a strand is the pitch of the helically wound wires. This distance is preferably equal to the total length of the stranded wire of the cable segment. This return distance can also be equal to half or one-third of the total length of the stranded wire. It is advantageous for reducing AC effects, particularly those that occur at higher alternating current frequencies when electrical current is passed through the winding, if the lay length is equal to or a multiple of the active length of the electric motor.

[0043] The flat wire can be insulated with a wire enamel. The use of an insulated flat wire, especially combined with insulated stranded wires, facilitates on-site insulation of the stranded wire segments during installation. In particular, surfaces that may be shaded from paint spraying during installation are protected. For contacting the flat wires or connecting a flat wire to a preformed strand, it is advantageous if the two ends of the flat wire are not coated with a wire enamel or if the wire enamel is removed from the end areas after flat wire pieces have been cut to length, e.g., mechanically ablated (e.g., by milling or grinding) or stripped off with laser stripping. The end areas of the flat wire should be free of wire enamel, at least on the contact surfaces, i.e., the surfaces to which, for example, a preformed strand or another flat wire is to be applied.

[0044] To create a connection between the preformed strand and the flat wire, it has proven particularly advantageous if the flat wire end area is designed with at least one compaction bevel. The compaction bevel is beneficial for a more even distribution of force when the flat wire end area and the preformed strand end area are pressed together. A major advantage of the compaction bevel is that the individual wires in the strand are not severed by a hard edge during welding. A first compaction bevel is located at the outermost end of the flat wire. This bevel prevents individual wires from shearing off during compaction. A second compaction bevel is located in the area of ​​the flat wire that is assigned to one of the outermost ends of the preformed strand. This compaction bevel is advantageous, among other things, in largely preventing any possible spreading of the preformed strand.Between the first compaction bevel and the second compaction bevel, the flat wire is stepped to a contact surface. The contact surface can extend, relative to a maximum height of the flat wire, approximately in the middle of the flat wire. The contact surface is preferably parallel to a flat wire surface. It can also be said that the flat wire is designed to be sufficiently thinner in its end region (e.g., ground down) that the compacted formed strand end region can fit thereon without exceeding a predetermined maximum height of the flat wire in the compaction segment as a whole. The flat wire end region is preferably tapered towards its end in the region of a segment contact surface. A compaction bevel is particularly advantageous if its helix angle is configured in an angular range of 10° to 70°, e.g., at 45°.

[0045] The pre-shaped stranded wire segment can be pressed into a geometric cross-sectional shape, for example to form a rod conductor. A first pre-shaped stranded wire segment of the pre-shaped stranded wire can serve to form a first rod conductor. The first pre-shaped stranded wire segment is preferably pressed into a first trapezoidal shape as a cross-sectional area. A second pre-shaped stranded wire segment of the same pre-shaped stranded wire can serve to form a second rod conductor. The second pre-shaped stranded wire segment can be pressed into a second trapezoidal shape as a cross-sectional area. It is particularly advantageous if both trapezoidal shapes have the same trapezoidal angle. It is also advantageous if both trapezoidal shapes can be seamlessly attached to one another.

[0046] Two trapezoidal shapes fit together particularly well when the smallest width of the first trapezoidal shape and the largest width of the second trapezoidal shape roughly match. When the trapezoidal shapes are combined with these widths, a larger trapezoid is created. The trapezoidal shapes are preferably selected so that a trapezoidal groove can be almost completely filled. The second trapezoidal shape can be taller than the first trapezoidal shape if both trapezoids have the same surface area. The surface area is determined by the cross-sectional area of ​​the shaped strand. By pressing, the shaped strand in at least one of the trapezoidal shapes can be packed into a more space-saving package of the individual wires with a compression factor of between 0.6 and 0.96, based on the cross-sectional area of ​​the twisted stranded wires.

[0047] A second compression-molded end of the pre-formed strand can be additionally compacted. During compaction, a greater pressing force can be exerted on the pre-formed strand than during compression molding. An upper limit for the force is determined by preventing the conductor material, e.g., copper, from flowing out of a compaction mold. The second end region of the pre-formed strand can be connected to a second flat wire end region of a second flat wire. This is a metallically conductive connection. The arrangement of the second flat wire and pre-formed strand encloses a second conductor segment angle. The first conductor segment angle can be equal to the second conductor segment angle. In particular, the second conductor segment angle can have a value in a range of 180° to 160°, preferably exactly 180°. This allows the conductor segment to be easily threaded into a groove (axially) or a bore, or pressed laterally into a gap or slot.

[0048] The compression-molded end region of the formed strand preferably extends over a compaction length. In the region of the compaction length, the formed strand can be wrapped in copper foil in combination with a flat wire. The copper foil preferably has a foil thickness ranging from 0.1 mm to 0.5 mm. This allows the copper foil to be applied particularly well to the flat wire and formed strand. A compaction length can have a value within a range of 2 mm to 25 mm. The compaction length is preferably 4 mm to 12 mm, for example 6 mm. A shorter compaction length allows a lower height of the (second) winding head. A longer compaction length can offer better mechanical strength. Preferably, the compaction area is pressed together with the copper foil or a correspondingly arranged copper bath. This creates particularly good contact. The copper strip orThe copper foil is a conductor bridge that connects the stranded wire and the flat wire.

[0049] The conductivity of the compaction area becomes particularly high when a hard solder is used to create an even better bond between the preformed strand and the flat wire. A hard solder is preferably present at least on one contact surface between the compression-molded end region of the preformed strand and the flat wire end region. The hard solder is applied as a hard solder platelet, which can have a compaction length and a width of the flat wire end region, i.e. is a rectangular platelet, onto the contact surface of the flat wire end region before the preformed strand end region is positioned on it. A hard solder layer can be created from the hard solder platelet, for example, by heating. A hard solder layer on the contact surface ensures a better electrical connection. The hard solder can initially be applied in a limited manner between two compaction bevels that may be present.By applying compaction pressure, the brazing filler metal can also be distributed across one or both contact slopes on the contact surface. This allows for the formation of a seamless compaction zone.

[0050] The flat wire should preferably be the same width as the braided wire or smaller than the braided wire. This allows the flat wire and braided wire assembly to be pushed into or through an opening without snagging, with the flat wire leading.

[0051] During the production of the pre-formed stranded wire or the production of the line segment, at least one bend can be created in the strand's extension in a central region. A U-shaped bend is advantageous for arranging the pre-formed stranded wire in a stator. The pre-formed stranded wire can be pressed into a linearly extending rod shape, also referred to as a rod conductor shape, in one or two extension regions spaced apart from the bend or the strand's curvature. This facilitates the formation of a winding, e.g., in a laminated core.

[0052] The cable segment can be covered with insulation. One advantageous insulation option is to wrap the cable segment or at least sections of the pre-formed stranded wire with insulating tape. It is often sufficient if the wrapping extends track to track, preferably laterally overlapping, starting at a first flat wire end area and extending to a second flat wire end area. This leaves the end areas free for contact formation. Preferably, only those areas are wrapped where wire enamel could be abraded at edges or contact surfaces and conductor material could be rubbed bare. This includes an area of ​​a winding overhang, which can in particular be formed exclusively by pre-formed stranded wire, as well as inlet openings or outlet openings in slots. This prevents possible short circuits, even during operation under strong vibrations.

[0053] The combinations and embodiments presented above can also be considered in numerous other connections and combinations.

[0054] A stator comprises a core, which can also be referred to as the winding core. The winding core carries the stator coils. A core constructed as a laminated core is particularly advantageous for guiding or forming a magnetic field. The core contains numerous bar conductors. The core is preferably cylindrical. More precisely, the core is designed like a hollow cylinder, with a rotor axis extending through a center of the core. The rotor axis is an axis of symmetry that passes through a cavity in the stator. The bar conductors are arranged around the rotor axis in the core. A radial distribution of the bar conductors results from at least a second group of bar conductors being at a greater distance from the rotor axis than a first group of bar conductors. If the arrangement of the bar conductors is viewed circumferentially, two bar conductors can be evenly spaced from one another.If the core is designed as a laminated core, the bar conductors, preferably all of the bar conductors, are arranged inside the laminated core. A receiving area for bar conductors in the laminated core can extend, in the form of a groove, away from the rotor axis into the laminated core. The bar conductors are arranged, in particular, electrically insulated from the laminated core. All bar conductors extend in the longitudinal direction or along the rotor axis of the stator. The bar conductor design is based on a hairpin design. In the shape of a hairpin, the bar conductors extend as compact bars, preferably straight, through the core or from one end of the core to an opposite end of the core. The bar conductors are designed as pre-shaped strands. A pre-shaped strand belongs to a line segment for electrical current. The line segment can also be referred to as a conductor segment.The braided wire is chosen to be long enough to accommodate at least two bar conductors. A first bar conductor is connected to a second bar conductor via a section of the braided wire. The first bar conductor is formed on one arm of the braided wire and the second bar conductor is formed on the other arm of the braided wire. Each arm of a braided wire has an end region. The bar conductors of the stator are arranged in the core in such a way that both end regions of the arms present on the braided wire open out on the same side, in particular on the same end face, of the core.

[0055] The stator also includes a number of interconnection webs, wherein the number of interconnection webs is preferably equal to the number minus one of bar conductors. An interconnection web connects two bar conductors to one another. In other words, an interconnection web is an electrical conductor for forming an electrical connection between a first formed strand and a second formed strand. The interconnection web extends directly, i.e. without any intermediate loss resistance, from an end region of a first formed strand to an end region of a second formed strand. The end regions each merge into a bar conductor. It is particularly advantageous for the formation of a web interconnection if interconnection webs are constructed in two parts. Both parts of an interconnection web can each be realized using a flat wire. The flat wires are preferably made of the same metal.A flat wire is an electrical conductor whose height or thickness is smaller than its width. A flat wire can have a rectangular cross-section. Flat wires can be supplied as strip material or as stamped sheet metal strips. Each flat wire preferably has wire enamel insulation. This virtually eliminates the possibility of short circuits between two interconnection bars. The interconnection bars are arranged outside the core. Interconnection bars can also be referred to as interconnection bridges.

[0056] Because a winding in a stator has a sequence of alternating shaped strands and interconnection webs, one can speak of a hybrid winding design of a stator according to the invention.

[0057] The hybrid winding design allows for comparatively simple stator manufacturing. Electrically conductive connections between the pre-formed strands in the stator and the interconnection bars can be created in a time-efficient and reliable manner using large-scale production processes, e.g., through synchronous contacting. With the pre-formed strands, the stator can achieve a very good conductor fill factor for conducting current through the windings.

[0058] The winding or windings of an electrical machine, in particular of its stator, comprise several line segments. A stranded wire is used to produce a line segment. The strand consists of several stranded wires, which can also be referred to as individual wires. Each individual wire is individually insulated by a coating. A coating with a thinly applied wire enamel can be sufficient to prevent a possible current flow from one individual wire to a parallel individual wire. The stranded wires are preferably arranged in bundles next to one another, with the individual stranded wires being twisted together. Twisted stranded wires extend next to one another in a curved manner in the bundle. The twisted stranded wires extend over a region of the longitudinal extent of the line segment, which can be referred to as the central region.The twisted stranded wires, as a bundle, have a cross-sectional shape that can be described as round or circular. The twisted strand is usually straight over its entire longitudinal extent, with the strand particularly retaining this length when it is formed into a shaped strand. Thus, the longitudinal extent of the strand and the longitudinal extent of the shaped strand are identical, or at least almost identical. To produce the line segment, the strand is advantageously bent at least once, which gives the strand a curved shape. Preferably, the arms of the strand extend linearly away from the bend in a first direction and in a second opposite direction. The strand curvature in the first, central region of the line segment is thus flanked by a second uncurved region and a third uncurved region along the longitudinal extent of the shaped strand.In the second region and in the third region, the stranded wire is pressed into a bar conductor shape. This, on the one hand, compacts the stranded wire. On the other hand, the stranded wire is given a cross-sectional shape that is desired for incorporating the stranded wire into an electrical machine. The bar conductor shape is preferably a linear shape of the line segment formed in the respective stranded wire region. The longitudinal extension of the shaped strand merges at both ends into so-called end regions. The end regions can be continuations of the bar conductor shape. The stranded wires can be twisted in the end regions. The stranded wire is converted into a shaped strand with its longitudinal extension through one or more pressing processes. Two provided flat wires are then added to the shaped strand. Both flat wires each have at least one end region at which there is no insulator. A central region of the flat wire is preferably insulated all around, e.g.with a thin layer of wire enamel. Each end of the pre-formed strand is connected to an insulator-free end of a flat wire. One end of the pre-formed strand's length is pressed together with the end of the associated flat wire, overlapping. The flat wire and pre-formed strand are brought into a metallically coherent connection in a respective first end region. A second flat wire is connected with its first end in the same way to a second end region of the pre-formed strand's length.

[0059] The compression ensures that the stranded wire cannot spread apart in the overlap area, deviating from the cross-sectional shape of the conductor. The connection can be created, for example, by applying energy. This creates a metallic conductivity through the fusion of the two parts, the preformed stranded wire and the flat wire, which preferably develops across the entire contact area of ​​the end sections, particularly without inclusions that would impede current conduction.

[0060] A stator constructed, among other things, from line segments according to the invention, as well as the inventive manufacturing method for a line segment, can advantageously be used in a drive train or for a drive train of a motor vehicle. The drive train has an electric machine for generating torque. The torque can be generated by means of a stator, which is usually installed stationary in the motor vehicle, and a rotor rotatably arranged therein. The rotor is preferably equipped with a magnet arrangement, which can be formed from permanent magnets. By supplying alternating current, variable magnetic fields can be generated, through which a force acting tangentially on the rotor enables a rotary movement of the rotor. This rotary movement or the associated torque is introduced into a torque transmission device.The torque transmission device may comprise one or more of the following components: an input shaft, an output shaft, a spur gear, a clutch, a planetary gear, a brake, and / or a differential. With a suitable current supply to the stator, a torque is applied from the torque transmission device to one road wheel (in the case of a single-wheel drive) or to multiple road wheels. The energy for the drive is provided from a rechargeable energy source of the motor vehicle. The required electrical current can be supplied to the electric machine in a controlled manner, for example, via power electronics that include an inverter.

[0061] Advantageous embodiments and further developments are set out below, which, viewed individually or in combination, may also reveal inventive aspects.

[0062] The formed strand preferably acquires its cross-sectional shape, at least in some regions, through compression molding. Compression molding allows the twisted strand to be particularly highly compacted. This enables a good fill factor in a slot (for example, a proportion of 0.5 to 0.95 of the slot volume can be filled with conductor material). Compression molding can form three strand segments along a strand's longitudinal extension. The strand segments are regions in which the strand has been given a different geometric cross-sectional shape, in particular one that differs from an adjacent region. Preferably, at least seven strand segments are compression molded. It is advantageous if a strand cross-section along the strand's longitudinal extension has a different cross-sectional shape for two of the compression-molded, preferably spaced-apart, strand segments, which preferably each extend linearly and serve as bar conductors.The strand cross-section of two strand segments, particularly those connecting to the bar conductors, can be identical. These strand segments can be of equal length in pairs. An unpressed strand section is preferably located between two strand segments with the same strand cross-section. An unpressed strand section is easier to bend than a compression-molded strand.

[0063] The two bar conductors formed by a preformed strand or embossed into a preformed strand are preferably of equal length. The length of the bar conductor is selected according to the longitudinal extent of the core or the laminated core along the rotor axis. In other words, the bar conductors can protrude a few millimeters (e.g., 5 mm) beyond the core. Preferably, (only) one compaction area of ​​the preformed strands protrudes beyond the core.

[0064] An insulator layer can be applied to the pre-formed stranded wire. Coating the pre-formed stranded wire with an insulator material ensures that no current can flow from the pre-formed stranded wire to the core. The insulator layer can extend over the entire bar conductor. It is also possible to provide an insulator layer that covers the entire length of the pre-formed stranded wire.

[0065] Several individual wires are arranged next to one another in the formed strand. The individual wires are twisted relative to one another. The individual wires extend within the formed strand from a first strand end to a second strand end. The stranded wires are preferably twisted together using a lay length. When twisted together using a lay length, this can be referred to as a 360° twist. There is preferably an overlap area between the two electrical conductors between the two end regions of the formed strand and a respective end region of the flat wire connected to the formed strand. An overlap area can, for example, be a predetermined length along the strand's longitudinal extension, ranging from 4 mm to 20 mm. The overlap area lies along the strand's longitudinal extension in one end region of the strand. The overlap enables better contact formation.

[0066] A first end of the formed strand belongs to a compaction segment of the formed strand. A second compaction segment of the formed strand is located at a second end of the formed strand. The first compaction segment is connected to a first flat wire. The second compaction segment is connected to a flat wire. The connection between a compaction segment and a flat wire end region is made using compression molding. Preferably, at least the end region of the respective flat wire assigned to the compaction segment is free of wire enamel. An electrically conductive connection can be created, for example, by soldering, welding using a diffusion welding process such as resistance welding or ultrasonic welding, or crimping, preferably hot crimping. During compaction, an electrically conductive transition from all individual wires to the flat wire is created via respective segment contact surfaces.

[0067] The preformed strand comprises several cross-sectionally shaped strand segments. Each cross-sectionally shaped strand segment of the preformed strand undergoes compression molding. Compression molding using a roller is possible. Due to the different cross-sections to be formed on a strand, shaping is preferably carried out in a mold. The mold determines the cross-sectional shape. Individual wires are collectively shifted simultaneously. All strand segments can, in particular, be molded into their respective cross-sectional shapes simultaneously.

[0068] Each stranded wire segment contains the same number of individual wires. The compression molding results in a roughly equal strand cross-sectional area. In other words, each cross-sectionally formed stranded wire segment has the same conductor cross-sectional area. The specified strand cross-sectional area is advantageous for power conduction.

[0069] The flat wires present in the stator can be assigned to a first group and a second group. Flat wires of the first group have a first flat wire width. Flat wires of the second group have a second flat wire width. The flat wires of the first group are each connected to a first end of an individual formed stranded wire assigned to them. The flat wires of the second group are each connected to a second end of an individual formed stranded wire assigned to them. The first width of the flat wires in the first group is smaller than the second width of the flat wires in the second group. The width of the flat wires is selected such that it is narrower than an inlet opening of a core slot. Preferably, at least two bar conductor regions belonging to at least two flat wires are located in each core slot. The flat wires can thus advantageously be introduced into the core slot in an axial direction. A web interconnection, i.e.A connection bridge can be formed using two flat wires. Preferably, stripped or uninsulated end sections of the flat wires are connected to form a connection bridge.

[0070] An electrical connection can be created using laser beam welding or another form of beam welding (e.g., with a charged particle beam). Bridge interconnections are particularly low-resistance connections between a first preformed stranded wire and a second preformed stranded wire. The connection is created by a material connection, e.g., from copper to copper.

[0071] A particularly high fill factor can be achieved if the cross-sectional area of ​​the stranded conductors of the preformed strand is adapted to a cross-section of a receiving space for the stranded conductor in the stator. If the receiving space has a trapezoidal shape, in particular if a trapezoidal shape reflects the cross-section of a longitudinal extension of the receiving space, a preformed strand of the stator is preferably also equipped with a trapezoidal shape.

[0072] The cross-section of the first bar conductor can fill a first trapezoidal shape. The cross-section of the second bar conductor can fill a second trapezoidal shape. It is particularly advantageous if both trapezoidal shapes have the same trapezoidal angle. Two trapezoidal shapes fit together even better if the smallest width of the first trapezoidal shape and the largest width of the second trapezoidal shape roughly match. A favorable trapezoidal angle results in particular from the radius followed by an inner core wall on the rotor side and the number and width of slots in the core. The first trapezoidal shape and the second trapezoidal shape can be put together almost seamlessly. When put together, both trapezoidal shapes form a trapezoidal height, preferably corresponding to a depth of the slot, of which the second trapezoidal shape can take up a larger proportion than the first trapezoidal shape.

[0073] It is particularly advantageous for stator assembly if the flat wire has a maximum width over its entire length, or at least over one end of the flat wire, that matches the width of the bar conductor to which the flat wire connects. A maximum flat wire width is preferably less than or equal to the bar conductor width. Furthermore, the maximum height of the flat wire should be less than or equal to the height of its connected bar conductor. This allows the flat wire and pre-formed stranded wire segments to be inserted particularly easily into the core.

[0074] Between the two arms of a formed strand there is a central region of the formed strand which serves as a spacer from one arm to the other. In other words, the central region forms a bridge between a first arm and a second arm of the formed strand. The central region is preferably a segmented region. The formed strand has at least two transition segments in the central region. At least one transition segment is designed with a cross-sectional press die. The transition segments can also be referred to as formed strand head segments. A cross-section of the transition segment is essentially rectangular. This means that a rectangular area is filled as a cross-sectional area by the individual wires of the formed strand in the transition segment. Due to the mostly used round shape of the individual wires, small gaps can be present between the individual wires, which can be used for examplecan be filled with an insulating varnish and / or a bonding varnish. If three transition segments or three preformed strand head segments are formed on the preformed strand, two of the segments or two transition segments preferably have the same rectangular cross-section. The rectangular cross-section of the transition segments is uniform over the length of the transition segments due to the compression molding.

[0075] A formed strand head region can be formed between the two arms of a formed strand. The formed strand head region is a formed region of the strand that is arranged in a winding head of the stator or is intended for arrangement in the winding head during a build-up phase. It is particularly advantageous if the formed strand head region has a (first) strand curvature. The curvature can be formed by loop forming, e.g., when the loop is stretched by pulling the two arms apart. A curvature formed in this way can result in an increase in the transverse extent of the formed strand. In that formed strand head region, which is preferably located in a central region of the formed strand, the transverse extent of the formed strand is greater than in a bar conductor region. During loop forming, the formed strand or the formed strand head region is brought into a loop-like extension.This preferably creates a track offset from one bar conductor to the adjacent bar conductor on a preformed strand. In the area of ​​the curvature of the preformed strand head, the preformed strand is not subjected to any cross-section-determining pressure. This at least preserves or slightly improves the softness of the preformed strand in that preformed strand head area, corresponding to the bendability of the twisted strand. This makes it easier to bend the preformed strand into a desired (spatial) 3D shape for positioning the bar conductors. Furthermore, a flatter winding head is possible.

[0076] The stator is equipped with at least one winding for conducting current, with a current passing through it generating a magnetic field around the winding. The winding is supported by the stator core. The winding, which is also referred to as a coil, is formed from a sequence of pre-formed wires and interconnection webs. A pre-formed wire follows an interconnection web. A pre-formed wire follows an interconnection web. The pre-formed wires, each combined with two flat wires, can preferably be inserted into the stator at the same time. Both arms of a pre-formed wire are inserted into different slots in the core. A first bar conductor of a pre-formed wire sits in one slot, preferably in an inner radial region of the slot, and a second bar conductor of the same pre-formed wire sits in another slot, preferably in an outer radial region of the other slot. Between these two slots, in the core orThe laminated core may contain additional slots, which are bridged in one winding head by one or more preformed stranded wire segments. In another winding head of the stator, several slots are bridged by an interconnection bar.

[0077] The combinations and embodiments presented above can also be considered in numerous other connections and combinations.

[0078] A stator for an electrical machine can be equipped with a laminated core in which a plurality of slots are present. The slots are preferably machined evenly distributed around the circumference, e.g., punched from the sheets that form the laminated core. The laminated core has a hollow cylindrical basic shape. This basic shape can be assigned an outer shell and an inner shell. The inner shell can also be referred to as the laminated core inner wall. The slots branch off into the laminated core via a gap in the laminated core inner wall (formed from individual sheet edges). The slots preferably extend longitudinally along the entire laminated core and can have a rectangular or trapezoidal cross-section. The hollow cylindrical shape of the laminated core has two end faces. A first winding head is located on a first end face. The first winding head is formed from arcuate central regions of a plurality of shaped strands.The preformed strands are shaped like hairpins. This includes, in particular, two linear extension areas each, which are connected via a transverse extension area of ​​the preformed strand. A second winding head is located on a second end face of the laminated core. The second winding head serves to connect the preformed strands to one another, in particular according to a predetermined winding structure plan or wiring plan. In other words, the first winding head preferably has no contact points of the windings, because the contact points are all located in the second winding head.

[0079] In an advantageous embodiment, there are exactly two pre-formed strands in each slot. Both pre-formed strands extend from the first winding head to the second winding head. The second winding head comprises a plurality of interconnection web bridges. An interconnection web bridge leads from a first pre-formed strand to a second pre-formed strand. Between a first pre-formed strand and a second pre-formed strand, there are at least two contact points on a line section. A contact point is an electrically conductive connection. This connection is designed with mechanical stability in that the connection is provided via a contact surface. The two pre-formed strands coupled with an interconnection web bridge are one pre-formed strand that is arranged in a first slot radially closer to the inner wall of the laminated core. This pre-formed strand is located inside the first slot. The other pre-formed strand, which belongs to the interconnection web bridge, extends in a second slot.It can rest directly on another internal preformed strand or be located in one or more preformed strand planes. In the second slot, the preformed strand is preferably located on a side of the slot facing away from the inner wall of the laminated core. It can therefore also be referred to as an external preformed strand. The inner wall of the laminated core serves to delimit an air gap to a rotor from the outside.

[0080] In a further embodiment, the second pre-stranded wire does not lie directly on the first pre-stranded wire, but there are further pre-stranded wires between the two pre-stranded wires. In this case, there are intermediate layers (e.g. made of pre-stranded wires) that separate the outer pre-stranded wire or the external pre-stranded wire from the inner pre-stranded wire located towards the stator center. The outer pre-stranded wire runs through part of a slot that is separated from the center of the stator or from a rotor axis by a larger radius than the radius to be formed between an inner pre-stranded wire and the rotor axis. In other words, the pre-stranded wires lie in different pre-stranded wire levels. For example, four pre-stranded wire levels can be formed per slot, resulting in four bar conductors lying one above the other. These typically belong to four different pre-stranded wires.

[0081] Segments in the middle area can also be called form strand head segments.

[0082] It is advantageous if a third shaped strand head segment is present between two shaped strand head segments, the strand extension of which has a screw thread-like curvature, such as a loop.

[0083] Accordingly, there can be at least three preformed strand head segments.

[0084] In a method described here for producing a stator for an electrical machine, a laminated core is provided which has a fixed number of slots. A predetermined number of pre-formed strands is also provided. The pre-formed strands are each equipped with a connecting web, such as a flat wire, at their two end regions. A connecting web serves to provide a current passage. In a first shaping step, which is a bending step, a central region of the pre-formed strands or of each pre-formed strand that serves the stator structure is curved in a pre-formed strand plane and thus brought into a U-shape. In a so-called joining step, all pre-formed strands of the stator are inserted into the slots in a laminated core longitudinal direction with the connecting webs first. The insertion preferably takes place for all pre-formed strands simultaneously. For joint insertion, the pre-formed strands can be inserted into an insertion tool beforehand.All preformed strands are pushed, in particular, side by side or in pairs, through the entire slot length until their connecting web protrudes from the laminated core on one side of the second winding head. Two connecting webs belonging to different preformed strands are then bent together or toward each other. The joined connecting webs form an electrically conductive connection, which can preferably be achieved by a uniform shape of the connecting webs, e.g., supported by a crimp, a solder, a sheathing tape, a contact shoe, and / or the introduction of thermal energy.

[0085] An assembly of an advantageous stator according to the invention with a provided rotor forms an electric machine with which a torque for a motor vehicle can be generated.

[0086] The result is a particularly compact electrical machine.

[0087] Further advantageous embodiments and developments are set out below, which, viewed individually or in combination, may also reveal inventive aspects.

[0088] The interconnection of cable segments can be carried out particularly quickly and almost error-free if a winding area of ​​the second winding head, preferably the entire winding area of ​​the second winding head, which adjoins the preformed strand segments in the laminated core, is designed without preformed strands.

[0089] The interconnection bridge is preferably formed from at least two interconnection bridge sections. The interconnection bridge sections can be secured to one another on one side in a V-configuration or a Y-configuration, providing electrical conduction. Preferably, the interconnection bridge sections and the interconnection bridge sections each have a rectangular cross-section. If exactly two interconnection bridge sections are present between two preformed strands, these interconnection bridges are connected to form the interconnection bridge at one broad side of their rectangular cross-section.

[0090] A wiring web section preferably has a width over its entire length that is less than or equal to the width of a stranded wire electrically connected to the wiring web section. The wiring web section is preferably configured accordingly with respect to a predetermined height of the connected stranded wire. This ensures that the wiring web section can be passed through a groove in the laminated core.

[0091] To gain an even better understanding of the stator interconnection, a perspective looking toward a stator shell can be taken. In such a shell side view of the stator, a first interconnection web section of a first interconnection web bridge and a second interconnection web section of a second interconnection web bridge appear as interconnection web sections arranged in different planes, overlapping one another in a mutually intersecting manner. This allows the interconnection webs to form a particularly compact or dense arrangement in a second winding head.

[0092] The preformed strand is preferably a strand pressed into a cross-sectional shape. Several strand segments are preferably formed along a strand's longitudinal extension, the number of which can in particular be an odd number, such as three strand segments or seven strand segments. A first strand cross-section of a strand segment differs from a second strand cross-section of an adjacent strand segment. An advantage of an odd number is that the strands between the two preformed strand segments in the laminated core can be particularly well placed together. Furthermore, the orientation of these two preformed strand segments can be adjusted particularly precisely during stator production.

[0093] The first winding head is formed by at least two preformed strand head segments, each of which constitutes one of the preformed strands of the stator, making up at least one winding. The two preformed strand head segments have a rectangular strand cross-section, preferably of equal area. A first broad side of a first preformed strand or of a preformed strand head segment faces a second broad side of a second preformed strand in the stator, to which the other preformed strand head segment belongs.

[0094] Good compactness of the (first) winding head can be achieved if the width of the broad side of the forming strand head segment is at least twice the height of the high side of the forming strand head segment.

[0095] The third preformed strand head segment is, in particular, an unpressed preformed strand head segment whose strand extension has a helical thread-like curvature, such as a loop. The third preformed strand head segment can form a coil head if, from a laminated core side, it has the greatest distance from all preformed strand head segments. The height of the third preformed strand head segment can be approximately 0.8 times the diameter of the preformed strand in its unpressed round form. In particular, two rectangular preformed strand head segments with a width-to-height ratio of 2.5 or more can be folded more easily if a third preformed strand head segment is located between them.

[0096] The stator has at least one winding for conducting current, which is designed as a repeating sequence of a braided wire and a connecting bridge. All windings of a stator can be designed as such a sequence. Each winding preferably has at least one winding end designed as a contacting wire. The contacting wire serves to conduct electrical current in and out. The stator is easy to install if the contacting wire terminates in an electrical plug-in connector or an electrical screw connector.

[0097] The pre-insulated wire can be wrapped from one interconnection bridge to the next interconnection bridge with a fabric tape, a polyimide tape, a fluoroethylene propylene tape, or a polyethylene naphthalate film. The pre-insulated wire can also be additionally encapsulated with a wire enamel, such as a polyesterimide enamel, or a synthetic resin or epoxy for insulation, particularly in a region of a first winding head. A particularly well-insulated stator can be provided if the second winding head, in particular the interconnection bridges, are also additionally encapsulated with such an electrical insulation material.

[0098] The stator can be equipped with a cooling system to reliably deliver higher motor power. A cooling fluid can be directed into the first winding head and / or the second winding head and / or the laminated core to cool operational heat. A coolant line attached to the outer casing is preferably provided for conducting coolant through the stator. Furthermore, one or more canned tubes can lead through the laminated core.

[0099] The winding overhangs each have a diameter transverse to a rotational axis or rotor axis of the stator. A diameter of the first winding overhang can be smaller than a diameter of the second winding overhang. Preferably, a height of the first winding overhang along the rotational axis is smaller than a height of the second winding overhang along the rotational axis.

[0100] A stator can be manufactured particularly efficiently when the number of formed strands equals the number of slots. This makes it easy to manage the number of parts that need to be assembled for a stator.

[0101] During stator manufacturing, a second bending step is preferably performed on the preformed strands before they are inserted into the laminated core. In the second bending step, one preformed strand, or preferably all preformed strands, are bent in a direction extending from a preformed strand plane, with at least one bend in the preformed strand head area. In particular, a track offset provided by the preformed strand is increased.

[0102] It is particularly advantageous for stator production if the shaped strands are pushed into the slots of the laminated core with both connecting web sections of a shaped strand leading. A connecting web section can also be referred to as an interconnection web section. One of the connecting web sections can be inserted into a first slot of the stator, and the other of the connecting web sections into a second slot, in particular using an assembly tool. It is particularly advantageous for further processing of the connecting web sections if the connecting web sections are pushed in until the connecting web sections that entered a slot entrance have completely exited a slot exit.

[0103] In a processing step during stator production, which can be performed additionally upon request, a winding head can be further compacted. Compaction is preferably carried out using a plate-like compaction tool. The shaped strands are compacted in a central region of the shaped strands, forming a winding head. By applying a pressure force in the direction of the rotor axis, the shaped strands of the stator are pressed together against the laminated core, thereby bending them toward the laminated core. This is particularly preferably done using a pressure plate that is part of the housing of the electrical machine.

[0104] A first group of connecting web sections can be longer than a second group of connecting web sections. This facilitates interlacing of the connecting web sections. Interlacing of connecting web sections in pairs, one section from the first group and one section from the second group, is preferably performed simultaneously using an interlacing tool.

[0105] An electrically conductive connection between the two connecting web sections can be created by energy treatment of a contact point between the connecting web sections. The connection can be made by beam welding.

[0106] Further advantageous aspects can also be described as follows, which can provide an inventive contribution both individually and in combination with one another. Form braid:

[0107] A pre-wired stranded wire consists of several individual wires with wire enamel insulation. The wires usually have a diameter ranging from 0.3 mm to 1.2 mm. Depending on the wire diameter, a predetermined number of individual wires are bundled together for each pre-wired strand in a stator. For example, 15 to 200 individual wires can be bundled and twisted into a strand with a predetermined lay length. Alternatively, the lay length can also be produced using stranding, twisting, or bundling. It is particularly advantageous if the lay length is equal to or a multiple of the active length of the electric machine for which the stator is intended. For an active length of a laminated core of 120 mm (millimeters), for example, the lay length should be either 120 mm, 60 mm, or 40 mm. Within the lay length, the wires make a helical twist of 360° (degrees) around a central axis of the bundle of individual wires.

[0108] Twisting individual wires with the appropriate pitch significantly reduces frequency-dependent losses (AC losses) that occur during operation of the motor or electric machine. The advantageous twisting of individual wires in a pre-formed stranded wire improves the performance and efficiency of the electric machine.

[0109] The twisted strand can be compressed by an additional twist, whereby a spiral-like loop is formed and pulled together in a coil head area of ​​the formed strand.

[0110] The twisted strand can be compacted in a pressing tool. Compaction preferably occurs in a manufacturing process following bundling and subsequent twisting. Alternatively, the strand can also be compacted by rolling. Tests have shown that greater compaction can be achieved by pressing than by rolling, therefore pressing is the preferred method. The ratio between the sum of the pure wire cross-sectional area of ​​the enamel-insulated, bundled individual wires and the total cross-sectional area of ​​the formed strand can be referred to as the compaction factor. This value typically ranges from 0.6 to 0.96.

[0111] Ideally, a geometric shape for compacting the braided wire is chosen that is based on the cross-section of the stator slot. An electrical machine can have square slot geometries, i.e., parallel slot boundaries equipped with square flat wires. A stator with annularly arranged, trapezoidal slots, whose boundary walls extend toward a rotational axis at a predetermined angle to one another, is particularly advantageous for achieving particularly good continuous performance in an electrical machine.

[0112] Preferably, a small clearance, such as a distance with a size corresponding to a value in the range 0.1 mm to 2 mm, is provided between the forming strand and the groove in order to facilitate the insertion of the forming strands into the groove or grooves, in particular at the respective position of the forming strands along a radial direction of the groove.

[0113] Another advantage of compression by pressing or compaction in a press mold is that different cross-sectional shapes, in particular different geometric shapes of a cross-sectional area, such as a round shape, e.g. circle or oval, a trapezoid, a rectangle or a square, can be formed along a strand's longitudinal extension.

[0114] Along the formed strand, the formed strand can be pressed in a first region, which can also be referred to as the bar conductor region, to a cross-sectional height with a value from a range of 3 mm to 12 mm and a maximum width with a value from the range of 1.5 mm to 10 mm. This is followed by a second region, which is in particular shorter than the first region. In the second region, the formed strand can be pressed to a cross-sectional height with a value from a range of 5 mm to 20 mm and a width with a value from the range of 1 mm to 7 mm. A third pressed region is preferably present across a coil head region and spaced from the second region, which has a cross-section dimensioned the same as the second region. A length of the third pressed region is preferably equal to the length of the second pressed region.In the non-compressed coil head area, the pre-formed wire can have a height from the value range of 4 mm to 16 mm and a width from the value range of 2 mm to 14 mm. A fourth compressed area follows the third compressed area. The fourth compressed area is preferably the same length as the first compressed area. The height of the fourth compressed area can have a value from the value range of 4 mm to 14 mm and a (maximum) width with a value from the value range of 1.5 mm to 8 mm. The fourth compressed area can also be referred to as the second bar conductor area of ​​the pre-formed wire, because the fourth compressed area is also intended for insertion into a slot of a laminated core.

[0115] The height and width values ​​of the compressed areas are also determined by the fact that they result in a nearly constant cross-sectional area. This can be considered a boundary condition. Cross-sectional shaping of the forming strand:

[0116] When the preformed stranded wire is trapezoidal, also known as wedge wire, like the slot in which the preformed stranded wire is or is to be arranged, particularly good electromagnetic properties are achieved. By compacting the preformed stranded wire into a geometric shape that optimally matches the slot, preferably trapezoidal, it is possible to increase the so-called copper fill factor. A high copper fill factor reduces the electrical resistance in the conductors and decreases direct current (DC) losses. This further increases the performance and efficiency of the electrical machine.

[0117] A stranded wire made of twisted, enamel-insulated individual wires is compacted and formed into different cross-sectional shapes in several different regions over a given length. While the cross-sectional shape differs in five consecutive regions of the formed strand, the cross-sectional area, determined by the sum of the cross-sections of the individual stranded wires, remains constant in all regions. However, in a coil head region, a lower degree of compaction of the stranded wires may exist than, for example, in the regions adjacent to the head region.

[0118] Two areas extending toward the ends of the preformed strand have a cross-sectional shape, usually trapezoidal, that optimally reflects the slot shape in the laminated core. The cross-sectional shapes of these two areas usually differ in height and width, since after insertion into the laminated core, they are located at different locations in different slots, i.e., at different radial positions.

[0119] At the center of each of the preformed strand end areas, there is a preformed strand transition area where the preformed strand is compressed into a flat, rectangular shape. The idea of ​​compressing these two areas into a flatter shape has a significant advantage for the resulting winding head height. The winding head height depends on the width of the preformed strand and is smaller the flatter the strand can be compressed.

[0120] In the head area between the aforementioned transition areas, the strand can optionally be compacted by an additional twist. This facilitates the joining of the transition areas. Flat wire:

[0121] The flat wire is preferably made of the same metal or metallic alloy as the pre-formed wire, preferably copper. The cross-section of the flat wire is typically rectangular, with a maximum width and height equal to the respective cross-section of the pre-formed wire in the bar conductor or slot area. The cross-section of the flat wire can be square. The corners and edges of the flat wire are rounded. Optionally, the cross-section of the flat wire can also be 0.1 mm to 4 mm smaller than the respective (maximum) width and / or height of the respective cross-section of the pre-formed wire in its slot area.

[0122] The flat wire has enameled wire insulation. The flat wire is processed before it is joined, specifically welded, to the stranded wire. Several pieces of flat wire are cut to the required flat wire length. The flat wire is stripped at one (first) end. This end serves for contacting other (stripped) flat wires or flat conductors (another word for flat wire). The flat wire is also stripped at the other (second) end. The second end serves for connecting to the formed stranded wire.

[0123] At the end intended for the pre-formed wire, a bevel is incorporated into the flat wire. The bevel is preferably created at an angle between 20° and 70°. This bevel is particularly advantageous for creating a very compact joint between the flat wire or its insulation-free end region and the pre-formed wire. The bevel serves to prevent the flat wire from potentially severing individual conductors when joining the wire. The bevel can also be curved or rounded.

[0124] When creating the joint, the flat wire and the shaped strand are preferably pressed together in an overlap area.

[0125] Severed individual conductors cannot conduct current and the risk of a reduction in the performance of the electrical machine is thus prevented. Joining connection between preformed strand and flat wire:

[0126] A joint between the preformed strand and the flat wire can be created by compacting the preformed strand. The cross-section of the joint is preferably smaller than or equal to the cross-section of the respective compressed bar conductor section of the preformed strand, particularly with regard to its height and maximum width. This allows for axial insertion of the bar conductor section of the preformed strand into the laminated core.

[0127] Although bar conductors can also be inserted into the laminated core in a radial direction, the slot opening in the laminated core must then be larger, especially large enough to allow both the bar conductor and the preformed stranded wire and its joining connection to fit through the slot opening. A larger slot opening usually results in a loss of performance. Furthermore, automated loading of a laminated core with bar conductors by axial insertion is less complex than by radial insertion into the slots.

[0128] In the area of ​​the joint, i.e. in a compaction area, a conductive copper foil or a conductive copper strip is preferably arranged as a sheath around the flat wire and the pre-formed strand. The thickness of the copper foil or copper strip is approximately 0.1 mm to 0.5 mm. In one area, this foil or strip can be overlapped. This copper sheath has, on the one hand, a reinforcing, mechanically strengthening effect on the compaction or compaction area. On the other hand, the conductivity of the sheath enables the resistance welding process for creating the material-to-material connection between the pre-formed strand and the flat wire.

[0129] Brazing solder may be present between the flat wire and the pressed preformed strand. The brazing solder is preferably inserted between the preformed strand and the flat wire before compaction. The brazing solder molten, for example, during a diffusion welding process of the copper joining partners and wets the preformed strand and the flat wire. This significantly improves the mechanical strength of the joint. The electrical conductivity of the brazing solder, e.g., due to its silver content, can have a positive effect on the electrical conductivity of the connection between the flat wire and the preformed strand.

[0130] By integrating the copper strip and brazing solder, the length of the compaction can be reduced while maintaining the mechanical strength requirements. This reduction is beneficial for low contact resistance. Potential electrical losses are thus reduced. It also results in a lower winding head height on the side of the laminated core where the flat wires are located in the stator.

[0131] The flat wire can be welded to the preformed strand in advance using a diffusion welding process, making it suitable for series production without any accessibility problems. Isolation:

[0132] A wire enamel, preferably made of polyamideimide with insulating properties according to DIN EN 60317-26, is used to electrically insulate individual wires from each other. The individual wires are preferably made of copper or a copper alloy.

[0133] A suitable single wire with a bare copper wire diameter of 0.71 mm can have a wire enamel coating thickness of 0.01 mm. A wire enamel coating is also called an overcoat. Optionally, an additional coating, known as a bonding coat, can be applied to the overcoat. A relatively heat-resistant material that is advantageous for this coating is polyamide. The bonding coat can have a layer thickness of 0.0095 mm, for example. The total wire diameter is therefore 0.749 ± 0.007 mm. The entire wire enamel has insulation class H.

[0134] A bonding coat can improve the stiffness of the preformed strand. For example, by heating the preformed strand, e.g., by conducting current or by convection or infrared ovens, the individual wires can be bonded or glued together.

[0135] Optionally, a bonding coat can be applied to the wire enamel of the individual wires. This can be thermally activated after the coil has been formed, bonding the individual wires together. The stiffness of the preformed strand can be further increased by a bonding coat, particularly in the area of ​​the bar conductors. Furthermore, a bonding coat can further improve the dimensional stability of the preformed strand, especially in the transition area.

[0136] Optionally, additional electrical insulation can be applied to the areas of the compacted stranded wire, particularly the compacted areas, and / or the flat wire. For example, by wrapping the stranded wire or flat wire with self-adhesive insulation tape, an insulating sheath can be created. This allows the wire enamel requirements and thickness in the stranded wire and flat wire areas to be reduced. With a reduced wire enamel thickness, for example, less than or equal to GRADE 1 (according to the standard for wire enamel thicknesses: IEC 60317-0-1:2013 + AM01:2019), higher copper fill factors can be achieved and the performance of the electric machine can be further increased. Extension forming of the forming strand:

[0137] The composite of pre-formed stranded wire and two flat wires is transformed from a nearly linear extension (apart from a possible helix in the head area) into a U-shaped extension. The extension is formed by bending the pre-formed stranded wire. In the areas where there is a transition between two different cross-sections of the pre-formed stranded wire, the pre-formed stranded wire is angled. The flat wires and the bar conductor sections of the pre-formed stranded wire remain aligned, preferably exactly linearly. The flat wires are a straight continuation of the bar conductor sections of the pre-formed stranded wire. The bar conductor sections in the composite with the flat wires are aligned parallel to each other. The transition sections are angled to each other in a roof-like manner. This first forming step can also be referred to as 2D forming. The formed U-shaped conductor or winding segments lie in a plane like hairpins.Additionally, a second forming step, also known as 3D forming, takes place, particularly afterward. During 3D forming, the transition areas of the preformed strand are each curved, causing the winding head to lie outside the plane defined by the conductor bars. This twisting allows for the creation of a very compact coil head or winding head.

[0138] The spirally preformed head area between the transition areas facilitates 3D forming. The individual wires within the strand can more effectively adapt or arrange themselves to an optimal transition path between the bar conductors before compression molding in the transition areas and the bar conductor areas fixes their longitudinal alignment. A further advantage of the more effective arrangement is the reduced forming forces that can act on the individual wires. This reduces the risk of wire breakage and untwisting in the cross-sectionally formed strand areas.

[0139] A compact coil head results in a smaller winding head. A smaller winding head reduces the space required for an electric motor. Shaping of the pre-formed stranded wire hairpin hybrid stator:

[0140] In a pre-wired hairpin hybrid stator, the coil or windings are partially formed from a so-called pre-wired hairpin hybrid. This uses a pre-wired wire whose shape resembles a hairpin. The pre-wired wire preferably transitions into solid, conductive flat segments at its ends.

[0141] For the automation of the axial insertion of coils or conductor segments into the slots of a laminated core, sufficient rigidity of the preformed strand is advantageous. The rigidity of the preformed strand is increased by compacting or pressing the strand. Depending on the joining concept and the intended assembly tolerances, a compacted preformed strand can already exhibit sufficient rigidity.

[0142] If a typical length of a laminated core is assumed to be in the range of 80 mm to 200 mm, a bar conductor area of ​​the pre-formed strand inserted into the laminated core preferably projects beyond the laminated core by a length in the range of 4 mm to 12 mm.

[0143] If the laminated core is equipped with conductor segments made of pre-formed stranded wire / hairpin hybrids, the flat wires of the conductor segment are interlaced. The interlacing is preferably performed in a forming process that is applied to all flat wires. Each first flat wire of a first conductor segment is bent toward the associated second flat wire of a second conductor segment. This results in a spatial crossover of the flat wires in an insulated area of ​​the flat wires. The uninsulated or stripped end regions of the two flat wires are preferably bent parallel to each other so that their contact surfaces lie on top of each other.

[0144] The flat wires, which belong together and are in particular already free of wire enamel at their ends, are preferably electrically connected to one another by (laser) beam welding.

[0145] Flat wire is particularly advantageous for the interlacing process because it is easier and more durable to form than stranded wire. There is no risk of stranded wire untwisting when the forming and interlacing for the second winding head is performed on flat wires.

[0146] Optionally, additional compression can be applied in the area of ​​the first winding head, which is formed from compacted preformed strands, preferably after the conductor segments have been fully assembled in the laminated core, e.g., using a pressure plate. This compression shortens the stator in an axial direction. With a conventional hairpin winding, which is made entirely of flat wire, such compression can lead to contact problems, among other things, because significantly greater compression forces must be applied.

[0147] The typical height of the winding heads depends heavily on the lamination pattern and the winding pattern. For a stator with a 120 mm inner diameter and a lamination stack with 60 slots, the height of the first winding head for an ASM machine can range from 30 mm to 55 mm. For a PSM machine, the winding head can range from 15 mm to 45 mm. For the second winding head of an ASM machine, the height is between 35 and 70 mm, and for a PSM machine, the height is between 20 mm and 60 mm. Welding or soldering hairpin hybrid conductor segments:

[0148] Tests have shown that direct welding of stranded wires without filler material is very difficult to achieve. The wire enamel on the individual wires within the strand impedes sufficient quality for electrical contact and a low-porosity contact surface. There is a high risk of contact resistance developing. This can also lead to embrittlement, cracking, and insufficient mechanical strength. In particular, an electrical connection between all individual wires can often not be ensured reproducibly. Outgassing of the wire enamel during the formation of the melt can cause very large ejections and pores within the weld seam, resulting in a poor bond surface.

[0149] This can be circumvented by using diffusion welding processes (such as ultrasonic or resistance welding). However, due to accessibility, these processes are not technically suitable for interconnecting the conductor segments or their flat conductors in the installed state. Beam welding, usually laser beam welding, is preferred, especially in series production with larger quantities. Stator design:

[0150] Hairpin machines are typically equipped with 4 to 10 layers of flat wires per slot to reduce AC losses.

[0151] Because the present pre-formed stranded hairpin hybrid conductor segments feature segmented individual conductors as cross-sectionally shaped strands within the slots, it has been determined that just two layers per slot are sufficient to prevent these losses. Consequently, only 50% to 20% as many hairpin conductor segments need to be manufactured compared to conventional hairpin wires. This can also significantly reduce the number of welds required.

[0152] A further advantage is the larger cross-section of the preformed strand compared to a single flat conductor of a state-of-the-art hairpin stator or hairpin electric machine. The cross-section of a preformed strand is approximately two to five times larger than that of conventional flat wire hairpins, which can result in somewhat higher rigidity for the preformed strand. Greater rigidity reduces the risk of failures during the automation of handling and joining operations in stator production.

[0153] In other words, in a preferred embodiment of the invention, exactly two preformed strands or bar conductors are present per slot. It appears that, due to the formation of the preformed strands from separate, bundled and twisted individual conductors, additional bar conductors in a slot - in contrast to a known hairpin machine with multiple flat wires in a slot - result in no or only a slight further improvement in performance. However, an increase in the number of preformed strands or bar conductors per slot, e.g., three or four preformed stranded bar conductors per slot, could be considered to implement a specific winding pattern. A further preferred embodiment of the invention provides for more than two bar conductors to be stacked one above the other in a single slot, in particular three to five bar conductors.

[0154] An example of an electrical machine that can advantageously be equipped with a stator according to the invention is an asynchronous machine (ASM machine).

[0155] A stator for an ASM machine, for example, may have an ASM stator, 60 slots in the laminated core, and four poles. This is a chorded configuration, in which a conductor segment, which can also be referred to as a coil with pre-formed strands, spans or jumps 13 slots in the first winding head. The connecting web present on the second winding head spans or jumps an average of 15 slots. Some of these connecting web jumps or spans encompass a larger number of slots.

[0156] Another example of an electrical machine that can advantageously be equipped with a stator according to the invention is a permanently excited synchronous machine (PSM machine).

[0157] A stator for a PSM machine, for example, may have 48 slots in the laminated core and 8 poles. This is an unstretched configuration, with a coil in the first winding head skipping or spanning 5 slots. In the second winding head, a connecting web also skipping or spanning 5 slots on average.

[0158] In principle, stators according to the invention can also be provided with a different number of poles and a different number of slots in the laminated core. The slot spanned by a U-shaped strand or the number of slots spanned by a connecting web can also be different – ​​regardless of the dimensions of the laminated core.

[0159] Typical performance data of an electrical machine or an electric motor equipped with a stator according to the invention are a peak power in a range of 100 kW to 450 kW (kilowatts), a peak torque in a range of 150 Nm to 650 Nm (Newton meters), a continuous power in a range of 80 kW to 300 kW, a maximum speed in a range of 15,000 rpm to 40,000 rpm (revolutions per minute) and an operating voltage in a range of 300 V to 850 V.

[0160] Some of the features described also include the following advantages: Production of a compacted stranded wire with different cross-sectional shapes. This enables the production of comparatively smaller winding heads for motors of a given power class compared to conventional motors. Combination of conductor segments with compacted stranded wire material and two enamel-insulated flat conductors. The configuration of conductor segments can be efficiently pre-produced for filling a placement tool. With the placement tool, all conductor segments or all bar conductors can be inserted simultaneously in the slots of the laminated core in the axial direction. Structure of the compaction for the connection of preformed stranded wire and flat wire with copper tape and brazing solder to create a compact joint. This creates a mechanically stable connection without significant contact resistance. Bevel on the flat conductor for creating the compaction.This ensures that all individual conductors are still permeable to electrical current after compaction. Very thin (= not standard according to the norm) wire enamel layers are used on the individual wire. This increases the copper fill factor in the slots. If necessary, external insulation of the conductor segment, in particular of the pre-formed wire, can be increased using insulation tape. Compared to known arrangements with several, more precisely up to ten, thin, flat wires inserted into a slot, the pre-formed wire offers increased rigidity. The number of conductors per slot can be reduced thanks to the use of pre-formed wires, in particular to two to four bar conductors per slot. This simplifies the manufacturing process, which also makes it less prone to errors. Structural design of the interconnection starting from the axial insertion of the pre-formed wire includingFlat wires in the slots; combination of U-shaped bent preformed stranded wire in the first winding head and interlaced flat conductors in the second winding head. This design offers further manufacturing advantages.

[0161] The combinations and embodiments presented above can also be considered in numerous other connections and combinations.

[0162] For example, a rotor can be equipped with a pre-formed stranded conductor or an advantageous hybrid conductor segment. A stator can have two laminated cores, each of which contains bar conductors arranged as pre-formed strands and connected via connecting bridges or flat conductors. Short character description

[0163] The present invention can be understood even better if reference is made to the accompanying figures, which illustrate particularly advantageous embodiments by way of example, without limiting the present invention to these, wherein Figure 1 shows an example of a twisted strand made from a bundle of individual conductors, Figure 2 a compaction of a twisted strand, similar to the strand according to Figure 1 , in a central area, Figure 3 a shaped strand which has different cross-sections along its longitudinal extent, in particular one made of Figure 2 known stranded wire manufactured form strand, Figure 4 shows an example of a trapezoidal single conductor arrangement of a compression-molded strand, in particular arranged in a groove of a laminated core, Figure 5 an example of a flat wire shows Figure 6 shows a cable segment consisting of a pre-formed strand and two flat wires, Figure 7schematically shows a cross-section through a compaction segment of a forming strand in an overlap area of ​​forming strand and flat wire, Figure 8 schematically shows a cross-sectional view taken as a right-angled section through the compaction segment and the flat wire of Figure 7 is formed, Figure 9 shows a wrapping of a cable segment with an insulating tape, Figure 10 shows a cable segment formed as a hairpin, which is formed from flat wire and pre-formed stranded wire and represents a hairpin hybrid, Figure 11 a view of a 3-D shaping of a hairpin according to Figure 10 shows, Figure 12 shows an insertion of a line segment into a core of a stator, Figure 13 shows an example of a stator structure in which a first winding head is formed on one side of the core, Figure 14 a cross section through the stator arrangement according to Figure 13 shows, Figure 15shows a stator with a second winding head in the structure, in which the flat wires are interlaced and laser beam welding takes place, Figure 16 a perspective view of the assembled stator Figure 15 shows, Figure 17 shows two possible arrangements of drive trains in a motor vehicle, Figure 18 a sequence of different process steps in the manufacture of an electrical machine, Figures 19a and 19b shows in a simplified schematic representation an assembly of an interconnection bridge by means of a material connection, Figure 20 shows a first shaped strand as a connecting element from one groove to a second groove, Figure 21 the one from Figure 20 known core with five shaped strands as connecting elements between different grooves of the core, Figure 22 a 3D view of the Figure 21 known core from the connecting bridge side, Figure 23shows an alternative winding arrangement (A) including a section (B), Figure 24 shows a fully populated core, Figure 25 shows a stator with a rotor, Figure 26a and Figure 26b show a stator in a motor housing with a pressure plate and Figure 27a and Figure 27b show a stator together with a rotor as internal parts of an electrical machine. Character description

[0164] Based on the Figures 1 to 17 Individual manufacturing steps and intermediate production states (semi-finished products) as well as alternatives to individual steps can be derived from the representations of the stranded wire 42, the formed stranded wire 50, 50 I< , 50 II< , 50 III< , the stator 2, 2 I< , 2 II< and the motor vehicle 500. Figure 1 starts with single wires 40, 40 I< , from which shaped strands 50, 50 I< , 50 II< , 50 III< can be formed (see Figure 3 ; see Figure 6), which can then be inserted into (core) slots 8, 10 of a stator 2, 2 I< , 2 II< in order to create, by means of further (conventional) manufacturing steps if necessary, an electrical machine 530, 530', 530 II< as part of a drive train 502 of a motor vehicle 500.

[0165] The Figures 19a to 27b show advantageous developments, alternative embodiments and similar solutions compared to the Figures 1 to 16 .

[0166] Figure 1 shows an example of a twisted strand 42 formed from a bundle of sixteen adjacently arranged individual wires, such as the individual wires 40, 40 I< . The individual wires extend continuously from a first strand end 44 to a second strand end 46.

[0167] The twisting of the twisted strand 42 can be carried out in such a way that the strand 42 maintains a very specific lay length 55 from the first strand end 44 to the second strand end 46. Each individual wire 40, 40 I< is braided, bent, or twisted in such a way that the twisted strand 42 has exactly the same arrangement of the individual wires 40, 40 I< at its second end 46 as at the first end 44 of the strand 42 (i.e., for example, the individual wire 40 that is at 12 o'clock at the first end 44 is at the 12 o'clock position in the twisted strand 42 at the second end 46 - similarly, for example, the individual wires at the 3 o'clock position, at the 6 o'clock position, and at the 9 o'clock position). In other words, the lay length is the length of one complete turn or coil of the wires in the strand around their axis. Ideally, the lay length is 55 to the length 6 of the core 4 (compare Figure 1 with Figure 12) are adjusted so that compliance with the lay length 55 results in two strand ends (at the outlet openings 19, 19 I< ) which have the same orientation or arrangement of the individual wires 40, 40 I<.

[0168] Advantageously, the formed strand to be produced has 50 II< (cf. Figure 12 ) a twist of the individual wires 40, 40 I< , which amounts to an integer multiple of a lay length 55, where the lay length 55 corresponds to an active length 6 of the stator or its core 4 (alternatively: a multiple of an (integer) divisor of the active length of the stator). The twisted strand 42, when formed as a pre-formed strand 50 II<, has a twist of the individual wires 40, 40 I< , which amounts to an integer multiple of a lay length 55. The lay length of the laminated core thus corresponds to an integer multiple of the laminated core length.

[0169] In Figure 2The twisted strand 42 is schematically shown with a straight strand extension 54. A strand curvature 82 is added to the strand 42 by means of a loop forming 80. Along the strand's longitudinal extension 54, the loop 81 is formed or drawn so tightly that a track offset 86 and a transverse extension 84 are formed that is larger than the original diameter of the linearly elongated strand (without reference symbol).

[0170] The Figure 3The formed strand 50 shown has a total length 56. The formed strand 50 is equipped with seven segments over its total length 56: a first segment 91, a second segment 92, a third segment 93, a fourth segment 94, a fifth segment 95, a sixth segment 96, and a seventh segment 97. The strand segments 91, 92, 93, 95, 96, and 97 generally have a substantially constant cross-section over their entire length. A first strand cross-section 105 is shown for the second segment 92. The third segment 93 has a second strand cross-section 106. A third strand cross-section 107 is present in the fourth segment 94. The fifth segment 95 has a fourth strand cross-section 108. A fifth strand cross-section 109 is formed along the sixth strand segment 96. The fourth strand segment 94 forms the central region 76 of the formed strand 50.In the unpressed central region 76, the shaped strand 50 has an elongated, rounded shape, which can also be referred to as an oval shape, according to the third strand cross-section 107. A first transition segment 100 borders the central region 76 or the fourth strand segment 94 on one side, and a second transition segment 101 borders the opposite side. Both transition segments 100, 101 each have a strand cross-section 106, 108 that has a rectangular cross-sectional shape 140, 142. The rectangular cross-sectional shapes 140, 142 have the same height 124 and the same width 122. A first arm 60, which is designed as a first bar conductor 64, borders the first transition segment 100. The first bar conductor 64 has a first trapezoidal shape 130. This cross-sectional shape is taken from that point on the rod conductor 64 which is defined by the first stranded wire cross-section 105 in the . Figure 3is shown. The first trapezoidal shape 130 has a first height 125 and a maximum width 123. The maximum width 123 transitions to a smallest width 136 of the trapezoidal shape 130. The first trapezoidal shape 130 has a height 139 which is smaller than a height 138 of the second trapezoidal shape 132. Adjacent to the second transition segment 101, as a sixth strand segment 96, is a second arm 62 on which a second bar conductor 66 is formed. The shaped strand 50 has a second trapezoidal shape 132 as a fifth strand cross-section 109 in the region of the second bar conductor 66. The second trapezoidal shape 132 has a second height 138. A maximum width 137 of the second trapezoidal shape 132 is smaller than a maximum width 123 of the first trapezoidal shape 130. The maximum width 137 of the second trapezoidal shape 132 approximately corresponds to a minimum width 136 of the first trapezoidal shape 130. The height 125 of the first trapezoidal shape 130 is smaller than the height 138 of the second trapezoidal shape 132.The first trapezoidal shape 130, the first rectangular shape 140, the second rectangular shape 142, and the second trapezoidal shape 132 thus form a sequence of cross-sectional areas 128 of the preformed stranded wire 50 along its total length 56. These cross-sectional shapes 128 result from a compression molding of the preformed stranded wire 50. Both bar conductors 64, 66 are of equal length. The rectangular shapes each have broad sides 141, 141 I<, which are intended to rest on other broad sides. Depending on the position of the preformed stranded wire 50, the height 124 of the rectangular shape 140 can also be referred to as the width 124 of the broad side 141. Similarly, the smaller width 122, which is located on a high side, such as the high side 143, can be referred to as a height 122 of the high side 143. After being molded into the formed strand 50, the strand 42 has different strand cross-sections 105, 106, 107, 108, 109.

[0171] In Figure 4a section of a core 4 is shown, the bar conductor 64 of which fills a slot 8; furthermore, Figure 4 the trapezoidal shape 130 of the rod conductor 64 is shown, which - like all (in Figure 3 shown) cross-sectional areas 128 - is formed from the same twisted strand 42. Thus, a constant cross-sectional area size 120 exists, which is determined by all individual wires, such as the individual wire 40. The height of the trapezoidal shape 138 is determined by the predetermined trapezoidal angle 134 of the first trapezoidal shape 130 at a predetermined radial distance. Figure 1It can also be seen that the individual wire 40, like the other individual wires (without reference numerals), has suffered a slight deformation of its originally round cross-sectional shape due to the pressing process. This results in additional compaction, which is more pronounced for thicker individual wires than in embodiments in which a correspondingly larger number of thinner individual wires are used to form a shaped strand (such as the shaped strand 50 according to FIG. Figure 3 ) with the same cross-sectional area (not shown).

[0172] Figure 5 shows an example of a flat wire 180. The flat wire 180 has a flat wire height 189 and a flat wire length 188. An end region 200 of the flat wire 180 is for a compaction region of a forming strand, such as the forming strand 50 in Figure 3, beveled - the compaction bevel 159. That end region 200, like the opposite end region 206 of the flat wire 180, is free of wire enamel insulation 210. The wire enamel insulation 210 extends only along the flat wire 180 in a region that extends between the end regions 200, 206.

[0173] Such a Figure 5 A rather schematically shown flat wire 180 can be used at the end of a Figure 3 known form strand 50 can be arranged.

[0174] In the Figure 6 In the line segment 39 I< shown, a braided wire 50 I< is connected - continuing on both sides - to a first flat wire 181 and a second flat wire 182 (before installing the braided wire 50 I< in a stator (such as the stator 2 according to the Figures 13 and 15)). The flat wires 181, 182, together with the shaped stranded wire 50, form a first line segment angle 59 and a second line segment angle 59. In the present example, this angle is approximately 180° in each case, but can also be smaller—preferably between 150° and 180°.

[0175] A smallest width 136 I< of the formed strand 50 I< transitions as seamlessly as possible to a first width 190 of the first flat wire 181 in the first compaction segment 150, in which a region 200 of the first flat wire 181 is overlapped. The first flat wire 181 has a flat wire end region 206, which simultaneously forms an end region of the line segment 39 I<. An opposite end region 208 of the line segment 39 I< is present on the second flat wire 182. In the present embodiment, a width 192 of the second flat wire 182 is greater than a width 190 of the first flat wire 181. Typically, however, the flat wires 181, 182 are approximately the same thickness. The width 192 of the second flat wire 182 merges into a smallest width of a second trapezoidal shape 137 I< , which is soldered almost continuously starting from the shaped strand 50 I< via a second compaction segment 152 to an end region 202 of the second flat wire 182.In the present embodiment, a first bar conductor 64 I< formed on the pre-formed stranded wire 50 I< has a shorter length than a second bar conductor 66 I< formed on the same pre-formed stranded wire 50 I<. Typically, however, all bar conductors 64 I<, 66 I< are approximately the same length.

[0176] In Figure 7 is the first compaction segment 150 after Figure 6drawn out in more detail. The formed strand 50 I< has a height 125 which is almost equal to a height 194 of the first flat wire 181. The height 194 of the first flat wire 181 encloses an insulator layer 210 I< which is formed by a wire enamel. A first segment contact bevel 154 and a second segment contact bevel 154 I< are incorporated in the flat wire end region 200 I<. The segment contact bevels 154, 154 I< have a bevel angle, such as the bevel angle 155 of the first bevel 154. The bevel angles of the segment contact bevels can be the same or different from one another. In the present case, the bevel angle 155 differs from the unspecified bevel angle of the segment contact bevel 154 I< . The helix angle 155 is more acute than the corresponding angle of the bevel 154 I< . Thus, the flat wire end range 200 I< is graduated.Between the segment contact slopes 154, 154 I< extends a segment contact surface 153, on which a hard solder 162 is arranged between the formed strand 50 I< and the first flat wire 181. The . Figure 5 The known compaction slope 159 is thus implemented in a stepped manner here - with two segment contact slopes 154, 154 I< and an intermediate segment contact surface 153. In an overlap region 204 between the first flat wire 181 and the formed strand 50 I<, the flat wire 181 and the formed strand 50 I< are wrapped with a copper strip 158. The copper strip 158 has a stabilizing effect, which is further enhanced by the fact that the copper strip 158 is laid in the region of the formed strand 50 I< as an overlapping double layer 160, also referred to as a copper strip overlap 160. The compaction segment has a predetermined compaction length 156, which is in particular greater than the height 125 of the formed strand 50 I<.

[0177] A cross section 157 from Figure 7is in Figure 8 The cross section 157 shows the overlap area 204 between the preformed stranded wire 50 I< and the first flat wire 181, surrounded by the copper strip 158 and the brazing alloy 162 as an intermediate layer. The preformed stranded wire 50 I< and the second flat wire 182 are connected in the same way as in Figure 7 and 8 for the first flat wire 181. An electrical connection 168 from the preformed strand 50 I< to the first interconnection web section 181 is formed via the brazing solder 162.

[0178] Out of Figure 9 It is apparent that a line segment 39, whose individual wire insulation within the formed strand 50 is deemed insufficient, can be additionally wrapped with an insulating tape 166, such as a fabric tape. The insulating tape 166 can cover the entire formed strand 50, including compaction segments, such as the first compaction segment 150. The - from Figure 5known - flat wire 180 is equipped with a wire enamel insulation 210, whereby only the flat wire end region 206 of the flat wire 180 is free of the wire enamel insulation.

[0179] The Figure 9 The winding of a braided wire, such as the braided wire 50, shown can also be transferred to a combination of braided wire 50 I< and flat wire 181, which consists of Figure 7 is known.

[0180] A line segment 39 I< is in Figure 10in a U-shaped form curved into a hairpin 70. In a formed strand head region 78, which is arranged in the central region 76 I< of the formed strand 50 I<, the first transition segment 100 and the second transition segment 101 of the formed strand 50 I< are angled towards one another. A strand bend 58 is present between the first transition segment 100 and the first bar conductor 64. The first bar conductor 64 has a bar conductor length 68. The bar conductor length 68 of the first bar conductor 64 is equal to the bar conductor length 69 of the second bar conductor 66. The second bar conductor 66 continues the second transition segment 101 at a second strand bend 58 I<. The first bar conductor 64 and the second bar conductor 66 extend parallel to one another. A first end region 72 of the formed strand 50 I< is laterally opposite an end region 200 I< of the first flat wire 181 and is connected thereto in a metal-to-metal manner. The first end region 72 of the formed strand 50 I< is for the (orduring the establishment of the connection with the first flat wire 181. Corresponding to the first end region 72 of the pre-formed stranded wire 50 I<, a second end region 74 of the pre-formed stranded wire 50 I< is also compacted and metal-to-metal connected to an end region 202 of the second flat wire 182. Thus, the line segment 39 I< is an electrically continuous composite of a pre-formed stranded wire 50 I< and two flat wires 181, 182. Flat wire end regions 206, 208 are located on the flat wires 181, 182, which simultaneously form the insulator-free end regions of the line segment 39 I<. The transition segments 100, 101 and the bar conductors 64, 66 lie in (or on) a pre-formed stranded wire plane 48.

[0181] Is based on Figure 10 a view of the line segment 39 I< towards the preformed strand head area 78, ie along the lengths 68, 69 of the rod conductors 64, 66, the view of the line segment 39 I< of Figure 11 .

[0182] In Figure 11 In the selected view, the first transition segment 100 of the cable segment 39 I< can be seen, from which the shaped strand 50 I< (see Fig. 10 ) via the shaped strand head area 78, which is designed as a type of joint, to the second transition segment 101. The two transition segments 100, 101 extend with a first track offset 86. In the selected representation of the hairpin 70 according to Figure 11 Because of the strand bends 58, 58 I< the rod conductors and flat wires of the hairpin 70 are made of Figure 10 not visible. The Figure 10 or Figure 11The hairpin 70 shown is the result of a 2D forming 1060 ("linear forming" performed in one plane). In a 3D forming 1070 ("linear forming" performed in all three spatial directions), the line segment 39 I< or its shaped strand 50 I< is formed into an enlarged track offset 86 I<. During the forming, in addition to the central region 78, the first transition segment 100 is given a third curvature 58" and the second transition segment 101 is given a fourth curvature 58 III<. In this case, in particular, the bar conductors (see bar conductors 64, 66 in Figure 10 ) into a position suitable for insertion into the core. If reference is made to the forming strand plane 48 of Figure 10 taken, the rod conductors 64, 66 are located after the 3-D forming 1070 according to Figure 11 still in that level 48, but the transition segments 100, 102 lead out of the stranded wire or bar conductor level 48.

[0183] Let us turn to one of Figure 3known form braid 50 again, then according to Figure 12an introduction of the cable segment 39 in a longitudinal or in an axial direction 24 along a rotor axis 22. The rotor axis 22 extends centrally through the core 4. The core 4 or the laminated core 4 has a fixed length 6. The cable segment 39 is inserted along the rotor axis 22 simultaneously into a first inlet opening 16 and into a second inlet opening 18. In this way, the central region 76 I< of the formed strand 50 II< (and also of the formed strand 50) reaches one end face 32 of the core 4. The cable segment is inserted with its flat wires 181, 182 leading the way until only the formed strand head region 78 stands out from the cable segment 39 above the laminated core 4, as can be seen on a second cable segment 39 II<. The shaped strand 50 II< extends beyond the length of the core 6.The second cable segment 39 II< is already inserted into the core 4, so that its shaped strand 50 II< is already located in the core 4 and its flat wires 181 I< , 182 I< protrude from the core 4 or the outlet openings 19, 19 I< belonging to the inlet openings 16, 18.

[0184] If the core 4 is completely equipped with conductor segments, such as the conductor segment 39 (or the pre-formed strand 50 I< ), the view of a stator 2 results according to Figure 13. On a first side 32 of the core 4, a first winding head 37 is formed, on which shaped stranded wire head regions, such as a first shaped stranded wire head region 78 and a second shaped stranded wire head region 78 I< , form a spatial closure. A first group of flat wires 220 and a second group of flat wires 222 extend from a second side 34 of the core 4, which serve to form a second winding head 38. The sheath 30 of the core 4 is therefore located between the first winding head 37 and the second winding head 38. The flat wires of the first group 220 each have a first height 194 and the flat wires of the second group 222 each have a second height 196. The second height 196 is greater than the first height 194. A cross section 29 through the core 4 equipped with line segments, such as the line segment 39, of Figure 13 is in Figure 14 shown.

[0185] According to Figure 14Gaps, such as the gap 20, which are embedded in a rotor-side core inner wall 31 of the stator 2, lead into core slots, such as the first core slot 8 and the second core slot 10. Figure 14 shows a section through all the trapezoidal conductors inserted into the core 4, such as the conductors 64, 66. A single stranded wire extends, for example, according to Figure 13connected in the first winding head 37, from a first radial region 12, an inner radial region 12 of the first core slot 8, to a second radial region 14, an outer radial region 14 of the second core slot 10. In a single slot, such as slot 8 and slot 10, inner bar conductors, such as bar conductor 64, are tightly packed together with outer bar conductors, such as bar conductor 66. In a core slot, such as core slot 10, two different shaped strands, such as shaped strands 50, 50 II<, are arranged. A first shaped strand 50 is inserted with its bar conductor 64 in the first slot 8 radially close to the inner wall 31. A second shaped strand 50 II< is inserted in the second slot 10 radially away from the inner wall 31. In addition, a further shaped strand 50 III< is inserted in the second slot 10 radially close to the inner wall. The second slot 10 is thus well filled.

[0186] In the Figure 15The stator 2 shown in an advanced stage of production are based on the arrangement of the stator 2 in Figure 13 The web interconnections 170 are formed in the second winding head 38. Previously, the formed strands (such as the formed strand 50, the formed strand 50 I<, and the formed strand 52) had been inserted. Arranged next to one another are several interconnection webs, such as the interconnection webs 172, 174, each having a metal-to-metal connection 232 produced by laser beam welding 230 at a contact surface 276 (see FIG. Figure 15 ).

[0187] Figure 16shows a perspective view of the finished stator 2, in which a winding runs through the core 4 from the first winding overhang 37, which sits on the first end face 26, to the second winding overhang 38, which is arranged on the second end face 28. In other words, the windings 36 extend from the first winding overhang 37 to the second winding overhang 38 and from the second winding overhang 38 to the first winding overhang 37. The second winding overhang has a plurality of interconnection web sections 272, 272 I< , 274, 274 I<. In all Y configurations, such as the Y configuration 270, a first interconnection web section 272 and a second interconnection web section 274 are welded to one another in the region of their contact points, such as the contact point 278.Due to the interlacing of all interconnection web sections, such as interconnection web sections 272, 272 I< , 274, 274 I< of the second winding overhang 38, interconnection web sections, such as a rear interconnection web section 272 I< and a front interconnection web section 274, cross over each other. This crossover occurs because both interconnection web sections 272 I< , 274 I< leading out of a common slot (not visible) are bent in opposite directions for all slots. The bending occurred as part of the interlacing process for the formation of the winding(s). A contact wire 256 leads from a winding end 250 to a connector 260, which enables an electrical connection to an inverter (not shown).

[0188] The design options explained with reference to the braided wire 50, 50 I<, connecting a simple flat wire 180 or alternatively a more complex flat wire 181, 182 to the braided wire 50, 50 I< (with or without insulating fabric tape 166 (see Figure 9 )), where the forming strand 50, 50 I< has at least three different forming strand segments (however, it can also have more than three different forming strand segments, e.g. five forming strand segments or e.g. even nine different forming strand segments), can also be combined as desired. It is even possible, as in Figure 13 shown to install different shaped strands 50, 50 I< , 52 in a stator 2.

[0189] In Figure 17A motor vehicle 500 is shown schematically, which is equipped with four wheels 551, 552, 553, 554. Two wheels 551, 552 are steerable. The wheels 551, 552 are connected to a first drive train 502. The drive train 502 on the front axle 504 includes a torque transmission device 510. The torque transmission device comprises a transmission 512. Drive shafts, such as the drive shaft 514, transmit torque to the road wheels 551, 552. The transmission 512 and an electric machine 530 are arranged in an overall housing 520. The electric machine 530 comprises a stator 2. The stator 2 is fastened to the overall housing 520. A rotor 540, by which the transmission 512 can be driven, is located in the stator 2. The first winding head 37 of the stator 2 is positioned adjacent to the gear 512.Due to the lower height of the first winding head 37 compared to the second winding head 38, the laminated core of the stator 2, in which the rotor 540 is located, is located particularly close to the gearbox. This enables a particularly low-transverse force coupling of the electric machine 530 to the gearbox 512.

[0190] A second example of a drive train 502 I\< is arranged on the rear axle 506 of the motor vehicle 500 and serves to drive two rear road wheels 553, 554. A first electric machine 530 I< , which has a first stator 2 I< , and a second electric machine 53 II< , which has a second stator 2 II< , are located in an overall housing 520 I< . Both electric machines 530 I< , 530 II< can each supply a torque to a transmission 512 I< in order to drive two road wheels 553, 554 via a torque transmission device 510 I<. All electric machines 530, 530', 530 II< are connected to a suitable power supply, e.g., via an inverter (not shown), for an electric machine.

[0191] In an advantageous method 1002, depending on the step up to which the method is processed, the production of a line segment 39, 39 I<, 39 II<, a stator 2, 2', 2 II<, 2 III< or an electric machine 530, 530', 530 II< can take place (cf. Figure 10 , 12 , 13 , 15 , 17 ). The starting point is the provision of insulated copper wire (process step 1004). A predetermined number of individual wires are cut to length and twisted together to form a strand (process step 1006). Depending on the preferred embodiment, this can also be referred to as twisting or stranding. By carrying out the process in parallel in process step 1076, a large number of stranded wires (cf. stranded wire according to Figure 1) and further processed. The stranded wires are formed to form a coil head (process step 1010). The forming 1010 is carried out by twisting the strand 42 in a loop-like loop 81 (cf. Figure 2 ). What follows is Figure 4 can also be seen - a compression of the respective strand 42 into different cross-sectional segments (process step 1020). During compression, a forming process can also take place, e.g., by pressing or compacting. In addition, a double number of flat wire pieces (see, for example, flat wire pieces 180, 181, 182 according to the Figure 5 , 6 , 7 and 8) is provided (process step 1030) and each flat wire piece, such as the flat wire pieces 180, 181, 182, undergoes a reworking of an end region in order to provide the flat wire piece with a bevel at the end (process step 1034) and to remove any wire enamel present at the end region (cf. Figure 7 ). In a subsequent step 1040, each formed strand is welded or soldered to two pieces of flat wire, one flat wire at each end of the formed strand - depending on the preferred embodiment (cf. Figure 6 ). Due to the parallel execution 1076, a predetermined number of line segments is available. Optionally, as can be seen from Figure 9 As can be seen from the drawing, an insulation tape can be provided (method step 1050) and the line segment can be wrapped with the insulation tape (method step 1052). Figure 10can be seen, a deformation of the line segment into a U-shape (method step 1060), which is a 2D shape. In a subsequent step 1070, the line segment is angled or rounded to form a 3D shape, whereby the line segment becomes a coil segment (cf. Figure 11 ). These forming steps can be carried out, for example, by bending, free-forming, or die-forming - depending on the preferred procedure. Due to the parallel execution according to method step 1076, a predetermined number of coil segments is thus available. In a subsequent step 1080, a laminated core is provided, into which the coil segments are inserted 1090 in an axial direction into the grooves of the laminated core to form the coil winding (cf. Figure 12 as well as Figure 14 ). This is followed - this is process step 1100 - by interlacing the flat wires protruding from the laminated core (cf. Figure 13 as well as Figure 15). The interlacing is achieved by a deformation, such as bending. Then, as in Figure 15 shown, the intertwined flat wires are welded together at their free end regions (method step 1110). The welding can be carried out, for example, by means of beam welding, laser beam welding, electron beam welding, or TIG welding. A first winding head and a second winding head are now present on the laminated core, which can optionally be further compacted by applying an axial force (method step 1120). As shown in method step 1140, connecting lines are provided one after the other for the created stator (see Figure 16) and insulation are provided (method step 1150). In a further processing step 1160, the connecting leads are first welded to the windings of the stator (or soldered, preferably in the same way as the previously described connection between a flat wire and a shaped strand). Subsequent potting of the windings with an insulation agent can optionally be carried out or omitted. In addition, the stator can be treated by impregnation or vortex sintering in order to prepare the stator for demanding environmental conditions. This is usually followed by an EOL (end-of-line) functional and quality control of the stator production. In a further step 1190, for the production of an electric machine (cf. Figure 18 ) the produced stator is combined with a provided rotor to form a final assembly (process step 1180).

[0192] Will the Figure 13 and the Figure 15placed next to each other, it can be seen that the first winding head 37, which is located on the first side 32 of the core 4, has already assumed its final shape as a connection or connecting means between individual bar conductors, but the second winding head 38 on the second side 34 of the core 4 still has to be interlaced in order to form the "half-finished" stator 2 with its groups 220, 222 of flat wires into a winding head 38 having web interconnections 170 by forming the interlaced interconnection web bridges 172, 174 by beam welding 230 with electrical through-contacts. The two sides 32, 34 of the core 4 are mirror surfaces on the centrally arranged stator cross-section 29 of the core 4. Because the outer surface 30 of the core 4 covers the bar conductors in its interior, ultimately only the winding heads 37, 38 are visible, as in Figure 15 shown, to see.

[0193] Figure 19ashows a laminated core 4 I< . The laminated core 4 I< shows, by means of its markings 5, 5 I< (markings 5, 5 I< , such as notches, beads, noses or impact marks, to indicate the rolling direction of the sheets of the laminated core 4 I< ), how the laminated core 4 I< is composed of individual sheets; this provides information on the magnetic flux in the core or in the laminated core 4 I< and the expected eddy current losses. The core 4 I< has a whole series of outlet openings 19, 19', in the area of ​​which the overlap area 204 I< , 204 II< between a bar conductor located inside the core 4 I< (bar conductors 64, 66 not in the view of the Figure 19a to see; cf. Figure 3 ; cf. Figure 6 ) and the interconnection web section 181 II< , 182 II<. The interconnection web section 181 II< has a flat wire length 188' that is greater than the flat wire length 188 II< of the second flat wire 182".

[0194] The interconnection web sections 181", 182" are arranged regularly distributed around the rotor axis 22. The laminated core 4 I< is a hollow cylinder, which is arranged in the Figure 19a shown view from above only (the first two, ie) two interconnection web sections 181", 182" (of a whole series during the assembly of a stator 2 (cf. Figure 13 ) of interconnection web sections to be attached).

[0195] Figure 19b shows interconnection bridge sections 181 III< , 182 III< in a joined, electrically conductive connection of the first interconnection bridge 172. Based on the Figure 19bThe joining of the interconnection web sections 181 III<, 182 III< can also be clearly seen thanks to the metallic (material) bond 232. From the laminated core 4 II< with its outer lugs as markings 5 ​​II<, 5 III<, the inner bar conductors extend in the circumference or length of the overlap areas 204 III<, 204 IV< in order to merge into the interconnection web sections 181 III<, 182 IV<. The bar conductors in the overlap areas 204 III<, 204 IV< are compacted pre-formed stranded sections before being joined to the interconnection web sections 181 III<, 182 IV<.

[0196] The characters Figure 20 , Figure 21 , Figure 22 show a two-layer arrangement of a braided wire-hairpin hybrid (in a simplified representation with initially only two central regions 76', 76" in the core 4 III< of the stator 2 III< ( Figure 20) and in the further development or construction of the stator 2 III< then with only four shaped stranded wires 99, 99 I< , 99 II< , 99 III< , which form the central areas 76 I< , 76 III< , 76 IV< , 76 V< ( Figure 21 ), i.e. with two forming strand levels 48', 48". Thus there is an inner forming strand level 48 II< and an outer forming strand level 48 I< .

[0197] On a first side 32 I< of the laminated core 4 III<, as can be seen from a summary of the Figure 20 with the Figure 21 This results in a stranded wire / hairpin hybrid being inserted - little by little - into the slots 8 I<, 10 I<, 10 II<, so that the central region 76 I<, 76 II<, 76 III<, 76 IV< rests on the first side 32 I<. The stranded wire legs 99, 99 I<, 99 II<, 99 III< protrude beyond the core 4 III< on the first side 32 I<. The core 4 III< is axially extended by the stranded wire / hairpin hybrids.

[0198] In Figure 20The two central areas 76 I< , 76 II< indicate the two-layer arrangement of the forming strands in the core slots 8 I< , 10 I< (on the two forming strand levels 48 I< , 48 II< ). If the forming strands sequentially fill all slots 8 I< , 10 I< , 10 II< (see also Figure 21 ), so when all the shaped strands are inserted, a first shaped strand level 48 I< and a second shaped strand level 48 II< are formed. Each groove is separated from the next groove by a groove wall 9. The Figure 20 The curvature 82 II< marked in the central area 76 I< creates compensation possibilities for core grooves 8 I< , 10 I< , 10 II< , whose exact position is subject to tolerances.

[0199] In the 3D view, which is Figure 22As shown, the arrangement of the center regions 76 III< , 76 IV< on one side 32 I< of the core 4 III< can be seen, while on the other side 34 I< of the core 4 III< the interconnection bridges 172, 174, 176, 178 protrude beyond the laminated core 4 III<. One winding head 37 is formed by center regions 76', 76 II< , 76 III< , 76 IV< , 76 V< of the pre-wired strands (see, for example, pre-wired strand 50 I< , shown in Figure 10 ). The other winding head 38 is formed by the interconnection bridges 172, 174, 176, 178, provided that the interconnection bridges 172, 174, 176, 178 are properly joined in a form-fitting manner.

[0200] When assembling a stator 2 III<, the markings 5, 5 I< , 5", 5 III< help to identify which side is the first side 32 I< of the core 4 III< and which side is the second side 34 I< of the core 4 III<. The first side 32 I< is the receiving side for the center areas 76 I< , 76 II< , 76 III< , 76 IV< , 76 V< of the forming strands (see forming strand 50 according to Figure 12 ).

[0201] Figure 23 shows a core 4 IV< of a stator 2 IV< with a four-layered braid arrangement. In each core slot 8 II< , 10 II< there are four braids 50 I< , 50 II< , 50 III< , 50 IV< with their braid head areas 78 I< , 78 II< , 78 III< , 78 IV<. Each braid extends over two braid levels 48 I< , 48 II< , 48 III< , 48 IV< ; the change of level takes place via the respective braid head area. As in Figure 23BAs can be seen, the conductors of the stranded wires 50 I< , 50 II< , 50 III< , 50 IV< fill the slots 8 II< , 10 II< with their (four) layers. A section has been taken as an example, with the slot designated by the reference symbol 8. The section in Figure 23B The trapezoidal shape of the conductor bars can also be seen - the conductor bars are formed into a shape that optimally fills the slots 8, 10. Instead of a trapezoidal shape, one can also speak of a wedge wire shape. The cross section of a stator slot 144 is shown in Figure 23B with a dashed line for emphasis. It can be seen that the stator slot in cross-section also has—roughly speaking—the shape of a trapezoid; more precisely, one could speak of a trapezoid or irregular quadrilateral.

[0202] If the stator 2 IV< is further equipped with shaped strands and interconnection bridges (cf. Figure 20 , 21 and 22), when the stator 2 IV< is fully equipped, the core 4 IV< looks like or similar to the stator 2 III< in Figure 24 when the stator is viewed from above.

[0203] As from Figure 24 As can be seen, the central areas 76 I< , 76 II< , 76 III< , 76 IV< , 76 V< of the shaped strands 50, 50 II< , 50 III< (see also Figure 14 ) on top of each other. The shaped strands 50, 50 II<, 50 III< overlap and thus conceal each other. This creates a compact winding head 37.

[0204] Should be from the stator 2 III< with its laminated core 4 III< , known from Figure 24 , an electric machine 530 III<, the equipment with a rotor 540 is still missing. In Figure 25The stator 2 III< with the rotor 540 is shown viewed from one end face. The rotor 540 includes a rotor shaft 542, which is a stepped shaft, and a rotor core 544. The rotor core 544 is arranged with an air gap 546 in the center of the stator 2 III<. If the stator 2 III<, which is built around its core 4 III<, is equipped with a rotor 540, the result is an electric machine 530 III<, similar to the one in Figure 25 The spline of the rotor 540, which is shown in Figure 25 As can be seen, a possible realization of the rotor 540 is inside or through the central axis of the core 4 III<.

[0205] Corresponding sectional views, one showing only a stator 2 III< and one showing a stator 2 III< equipped with a rotor 540 I<, are shown cut along the rotor axis 22 in the Figure 26a , 26b , 27a , 27b shown.

[0206] The Figure 26aand 26b show a stator 2 III< , once from the "connection bridge side" (see Figure 26b ) and once from the "form strand head area side" (see Figure 26a ). The Figure 27a and 27b show the one from the Figure 26a and 26b known stator 2 III< with an integrated rotor 540'. The rotor 540 I< is spaced from the winding 36 of the stator 2 III< by the air gap 546.

[0207] In the Figure 26a and 27a The stator winding 36 is shown on the first side 32 with a compacted winding head 37. Compaction is achieved by a pressure plate 522 integrated into the overall housing 520 or into the core 4 V<. In a central region of the shaped strands, the strands are pressed against the laminated core by the pressure plate 522 and thereby compacted.

[0208] In the particularly preferred embodiment, the pressure plate 522 is part of the housing 520 and thus integrated into the electrical machine. During and through the assembly of the electrical machine, the winding head 37 is thus compacted. In the fully assembled machine, the formed strands are thus even further compacted.

[0209] The design options shown in the individual figures can also be combined with one another in any desired way. For example, if reference is made to a first segment 91, a second segment 92, a third segment 93, etc., such numbering, in particular a sequential one, can be interchanged without deviating from the described object. List of reference symbols

[0210] 2, 2 I< , 2 II< , 2 III< , 2 IV< Stator 4, 4 I< , 4 II< , 4 III< , 4 IV< , 4 V< Core, in particular laminated core 5, 5 I< , 5 II< , 5 III< Laminated core marking 6 Length of the core, in particular length of the laminated core 8, 8 I< , 8 II< Slot, in particular first core slot 9 Slot wall 10, 10 I< , 10 II< Second core slot 12 First radial region 14 Second radial region 16 First inlet opening, in particular first slot entrance 18 Second inlet opening, in particular second slot entrance 19, 19 I< Exit opening, in particular slot exit 20 Gap 22 Rotor axis, such as a rotational axis through the stator 24 Longitudinal direction 26 First end face or first end side 28Second end face or second end side 29Stator cross-section 30Shell surface, like an outer shell 31Inner core wall, in particular rotor-side inner wall of a laminated core, 32, 32 I< first side of the core 34, 34 I< second side of the core 36Winding, in particular winding area 37First winding head 38Second winding head 39, 39', 39"Cable segment 40, 40 I<Single wire, in particular enamel-insulated stranded wire 42 twisted strand 44 first strand end 46 second strand end 48, 48 I< , 48 II< , 48 III< , 48 IV< stranded wire level, in particular bar conductor level 50, 50 I< , 50 II< , 50 III< , 50 IV< stranded wire, in particular first stranded wire 52 stranded wire, in particular second stranded wire 54 stranded wire length 55 lay length 56 total length of the stranded wire 58, 58 I< , 58 II< , 58 III< strand bend 59 first line segment angle 59 I< second line segment angle 60 first arm 62 second arm 64, 64 I< first bar conductor 66, 66 I< second bar conductor 68 length of the first rod conductor 69Length of the second rod conductor 70Hairpin 72First end region of a shaped strand 74Second end region of a shaped strand 76, 76 I<, 76 II<, 76 III<, 76 IV<, 76 V<, 76 VI<, 76 VII<, 76 VIII< Middle region of a shaped strand 78, 78 I< Shaped strand head region, in particular region in the middle between the arms of a shaped strand, in which shaped strand head segments are located 80Loop formation81Loop 82, 82 I< , 82 II< Curvature, in particular strand curvature 84Transverse extension 86, 86 I< Track offset 91First strand segment, such as a first region of a shaped strand 92Second strand segment, such as a second region of a shaped strand 93Third strand segment, such as a third region of a shaped strand, in particular shaped strand head segment 94Fourth strand segment, such as a fourth region of a shaped strand, in particular shaped strand head segment, such as a third shaped strand head segment 95Fifth strand segment, such as a fifth region of a shaped strand, in particular shaped strand head segment 96Sixth strand segment, such as a sixth region of a shaped strand 97Seventh strand segment, such as a seventh region of a shaped strand 99, 99 I< , 99 II< , 99 III< Form strand leg 100First transition segment, in particular first form strand head segment 101Second transition segment, in particular second form strand head segment 105First strand cross-section 106Second strand cross-section 107Third strand cross-section 108FourthStrand cross-section 109 Fifth strand cross-section 120 Strand cross-sectional area size 122 First width of the shaped strand, in particular height of the high side 123 Second width of the shaped strand, in particular maximum width of a first trapezoidal shape 124 Height of the shaped strand, in particular width of a wide side 125 Height of the shaped strand, in particular height of the first trapezoidal shape 128 Sequence of different cross-sectional areas 130 First bar conductor shape, in particular first trapezoidal shape 132 Second bar conductor shape, in particular second trapezoidal shape 134 Trapezoid angle 136, 136 I< smallest width of a first trapezoidal shape 137 largest width of a second trapezoidal shape 137 I< smallest width of a second trapezoidal shape 138 Height of a second trapezoidal shape 139 Height of the first trapezoidal shape 140 Rectangular strand cross-section, in particular first rectangular cross-sectional shape 141, 141 I< first broad side 142rectangular strand cross-section, in particular second rectangular cross-sectional shape 143high side 144cross-section of a stator slot 150firstCompaction segment 152Second compaction segment 153Contact point, in particular segment contact surface 154, 154 I< Segment contact bevel 155Bevel angle 156Compaction length 157Cross-section of the compaction segment 158Copper foil, in particular copper strip 159Compaction bevel 160Copper strip overlap, in particular copper strip double layer 162Brazing solder 166Insulator layer, in particular insulating strip 168Electrical connection 170Bridge interconnection 172First interconnection bridge, in particular first interconnection bridge 174Second interconnection bridge, in particular second interconnection bridge 176Third interconnection bridge, in particular third interconnection bridge 178Fourth interconnection bridge, in particular fourth interconnection bridge 180Flat wire 181, 181 I< , 181 II< , 181 III< first interconnection web section, in particular first flat wire 182, 182 I< , 182 II< , 182 III< second interconnection web section, in particular second flat wire 188, 188', 188" flat wire length189Flat wire height 190First width, in particular width of a first flat wire 192Second width, in particular width of a second flat wire 194First height, in particular height of a first flat wire 196Second height, in particular height of a second flat wire 200, 200 I<End region of the first flat wire, in particular flat wire end beveled for compaction 202End region of the second flat wire, in particular flat wire end beveled for compaction 204, 204 I<, 204 II<, 204 III<, 204 IV<Overlap region 206Flat wire end region of a first flat wire, in particular insulator-free region 208Flat wire end region of a second flat wire, in particular insulator-free region 210, 210 I<Wire enamel insulation, in particular wire enamel layer 220First group of flat wires 222Second group of Flat wires 230Beam welding, especially laser beam welding 232Metallic connection 250Winding end 256Connector 260Contacting wire270Y-configuration 272, 272 I< first interconnection web section of a first line segment 274, 274 I< second interconnection web section of a second line segment 276Contact surface, in particular broadside contact surface 278Contact point, in particular material-to-material connection 500Motor vehicle 502, 502 I< Drive train 504Front axle 506Rear axle 510, 510 I< Torque transmission device 512, 512 I< Transmission 514Drive shaft 520, 520 I< Overall housing 522Pressure plate, in particular as an integrated part of the overall housing 530, 530 I< , 530 II< , 530 III< Electric machine 540, 540 I< Rotor 542Rotor shaft 544Rotor laminated core 546Air gap 551First road wheel 552Second road wheel 553Third road wheel 554Fourth road wheel 1002Method for producing a stator and an electric machine 1004Providing insulated copper wire 1006Cutting and twisting individual wires to form a stranded wire 1010Forming the stranded wire to form a head region of a shaped stranded wire1020Condensation of the formed strand in areas with different cross-sections 1030Provision of two flat wire pieces that are stripped at their ends 1034Forming an end region on each flat wire piece with a bevel 1040Welding or soldering a formed flat wire end region to a formed strand end region in a compressed overlap region 1050Optional provision of an insulation tape 1052Optional wrapping of the formed strand with an insulation tape 1060Bending of the formed strand into a U-shape (2D forming) 1070Bending of the formed strand into a line segment shape or coil segment shape (3D forming) 1076Parallel execution of the production of the line segments for a stator 1080Provision of a laminated core equipped with slots for the assembly of a stator 1090Insertion of all Cable segments into the grooves of the laminated core in the axial direction 1100 Interlacing of the flat wires by bringing together interconnection web sections1110 Welding of the flat wires in pairs at their free ends or end areas 1120 Optional compaction of a winding head 1140 Provision of winding connection cables 1150 Provision of insulation and / or potting compounds 1160 Contacting and enclosing the winding heads 1180 Optional provision of a rotor 1190 Optional assembly of stator and rotor to form an electric machine

Claims

1. Conductor segment (39, 39I, 39II) for a winding (36) of an electric machine (530, 530I, 530II, 530III), the conductor segment being constructed from three metallically conductive portions, of which a first portion is a shaped stranded wire (50, 50I, 50II, 50III, 50IV), characterized in that a first flat wire (180, 181, 181I, 181II, 181III) and a second flat wire (182, 182I, 182II, 182III are further portions, which are electrically conductively connected to the shaped stranded wire, wherein a joined connection is formed between a first end region (72) of the shaped stranded wire (50, 50I, 50II, 50III, 50IV) and a first flat wire end region (200, 200I) of the first flat wire, and a further joined connection is formed between a second end region (74) of the shaped stranded wire and a first flat wire end region (202) of the second flat wire.

2. Conductor segment according to claim 1, characterized in that the conductor segment has in each case a compressed overlap region (204, 204I, 204II, 204III, 204IV) formed of the joined first flat wire end regions (200, 200I, 202) and the respective end regions (72, 74) of the shaped stranded wire (50, 50I, 50II, 50III, 50IV).

3. Conductor segment according to claim 2, characterized in that a conductive copper foil (158) or a conductive copper tape is provided as a sheath around the overlap region (204, 204I, 204II, 204III, 204IV).

4. Conductor segment according to any one of the preceding claims, characterized in that an intermediate layer of hard solder (162) is present between the end regions (72, 74) of the shaped stranded wire (50, 50I, 50II, 50III, 50IV) and the first flat wire end regions (200, 200I, 202).

5. Conductor segment according to any one of the preceding claims, characterized in that the shaped stranded wire (50, 50I, 50II, 50III, 50IV) is connected to the first flat wire end region (200, 200I) of the first flat wire (180, 181, 181I, 181II, 181III) so as to form a first conductor segment angle (59), which is an angle in an angle range of 180° to 150°, and is connected to the first flat wire end region (202) of the second flat wire (182, 182I, 182II, 182III) so as to form a second conductor segment angle (59I), which is an angle in an angle range of 180° to 150°.

6. Conductor segment (39, 39I, 39II) according to any one of the preceding claims, characterized in that the shaped stranded wire (50, 50I, 50II, 50III, 50IV) consists of a plurality of wires (40, 40I), and in that all the wires of the shaped stranded wire extend continuously from the first end region (72) of the shaped stranded wire to the second end region (74) of the shaped stranded wire and into the respective first flat wire end region (200, 200I, 202).

7. Conductor segment (39, 39I, 39II) according to claim 6, characterized in that the wires (40, 40I) are twisted with a lay length (55) which is equal to or a submultiple of an active length of the electric machine.

8. Conductor segment (39, 39I, 39II) according to any one of the preceding claims, characterized in that the flat wires (180, 181, 181I, 181II, 181III, 182, 182I, 182II, 182III) are wire-enamel-insulated flat wires (180) which each have two flat wire end regions (200, 200I, 202, 206, 208) that are free of wire enamel at least on a segment contact surface (153).

9. Conductor segment (39, 39I, 39II) according to any one of the preceding claims, characterized in that the first flat wire end region (200, 200I, 202) is formed with at least one compaction slope (159).

10. Conductor segment (39, 39I, 39II) according to any one of the preceding claims, characterized in that one compressed strand segment (92) of the shaped stranded wire (50, 50I, 50II, 50III, 50IV) is pressed into a first trapezoidal shape (130) as a cross-sectional area (128) thus formed as a first bar conductor (64, 64I), and a further compressed strand segment (96) of the same shaped stranded wire is pressed into a second trapezoidal shape (132) as a cross-sectional area (128) thus formed as a second bar conductor (66, 66I).

11. Conductor segment (39, 39I, 39II) according to claim 10, characterized in that a smallest width (136, 136I) of the first trapezoidal shape (130) and a largest width (137) of the second trapezoidal shape (132) approximately match, wherein the second trapezoidal shape (132) has a larger height (138) than the first trapezoidal shape (139), and wherein the shaped stranded wire (50, 50I, 50II, 50III, 50IV) is brought into at least one of the trapezoidal shapes (130, 132) with a compression factor of a value between 0.6 and 0.96 relative to a strand cross-section of the twisted strand (42).

12. Conductor segment (39, 39I, 39II) according to any one of the preceding claims 3 to 11, characterized in that the copper foil (158) has a foil thickness in a range of 0.1 mm to 0.5 mm.

13. Conductor segment (39, 39I, 39II) according to claim 4, optionally in combination with any one of claims 5 to 12, characterized in that the hard solder (162) is present at least on a segment contact surface (153), the segment contact surface (153) being delimited by two segment contact slopes (154, 154I) which are incorporated in the flat wire end region (200, 200I, 202).

14. Conductor segment (39, 39I, 39II) according to any one of the preceding claims, characterized in that the flat wires (180, 181, 181I, 181II, 181III, 182, 182I, 182II, 182III) are formed with a width (190, 192) equal to or smaller than that of the shaped stranded wire (50, 50I, 50II, 50III, 50IV).

15. Conductor segment (39, 39I, 39II) according to claim 13 or 14, characterized in that the first flat wire end region (200, 200I, 202) tapers toward its end in the region of the segment contact surface (153).

16. Conductor segment (39, 39I, 39II) according to any one of claims 13 to 15, characterized in that the segment contact slopes (154, 154I) are formed with a slope angle (155) in an angle range of 10° to 70°.

17. Method for producing a conductor segment (39, 39I, 39II) for a winding (36) of an electric machine (530, 530I, 530II, 530III), the conductor segment comprising a shaped stranded wire (50, 50I, 50II, 50III, 50IV), characterized in that a first and a second flat wire (180, 181, 181I, 181II, 181III, 182, 182I, 182II, 182III) are made available, and in that the shaped stranded wire is assembled with the flat wires to form the conductor segment, by electrically conductively connecting a first end region (72) of the shaped stranded wire to a first flat wire end region (200, 200I) of the first flat wire (180, 181, 181I, 181II, 181III) and a second end region (74) of the shaped stranded wire to a first flat wire end region (202) of the second flat wire (182, 182I, 182II, 182III) by means of a joining process, in particular beam welding, preferably laser beam welding.

18. Method according to claim 17, characterized in that a strand curvature (82) is created in a middle region (76) of the shaped stranded wire (50, 50I, 50II, 50III, 50IV), and the strand (42) is pressed into a bar conductor shape (130, 132) in extension regions located at a distance from the strand curvature (82).

19. Method according to claim 17 or 18, characterized in that an intermediate layer of hard solder (162) is introduced between the end regions (72, 74) of the shaped stranded wire (50, 50I, 50II, 50III, 50IV) and the first flat wire end regions (200, 200I, 202), which intermediate layer is melted during the joining process and wets the shaped stranded wire and the flat wire end regions.

20. Method according to any one of claims 17 to 19, characterized in that an overlap region (204, 204I, 204II, 204III, 204IV) consisting of the joined first flat wire end regions (200, 200I, 202) and the respective end regions (72, 74) of the shaped stranded wire (50, 50I, 50II, 50III, 50IV) is compacted.

21. Method according to claim 20, characterized in that a conductive copper foil (158) or a conductive copper tape is arranged as a sheath around the overlap region (204, 204I, 204II, 204III, 204IV).

22. Method according to any one of claims 17 to 21, characterized in that the shaped stranded wire (50, 50I, 50II, 50III, 50IV) and the flat wires (180, 181, 181I, 181II, 181III, 182, 182I, 182", 182III) are each oriented with a conductor segment angle (59, 59I), which is an angle of approximately 180° to 150°, so that, apart from a possible strand curvature (82), the conductor segment (39, 39I, 39II) extends substantially linearly before it is installed in the winding.

23. Method according to any one of claims 17 to 22, characterized in that the conductor segment (39, 39I, 39II) is covered or wrapped with insulation, in particular wrapped with an insulating tape (166), with the insulation extending only up to a second flat wire end region (206, 208) of the first and / or second flat wire (180, 181, 181I, 181II, 181III, 182, 182I, 182II, 182III).

24. Motor vehicle (500) comprising a drivetrain (502, 502I), characterized in that the drivetrain (502, 502I) comprises an electric machine (530, 530I, 530II, 530III) having at least one winding (36), in which at least one conductor segment (39, 39I, 39II) according to any one of claims 1 to 16 is installed.