Method for manufacturing a stator winding of a stator, electric machine and motor vehicle

Abstract

The present invention relates to a method for manufacturing a stator winding (1) of a stator (2) of an electric machine (3) for powering a motor vehicle (4). First, a stator body (5) with a longitudinal axis (6) and a plurality of stator slots (7) is provided. Hairpins (8) are arranged in the stator slots (7). Hairpin end sections (9) projecting from an end face of the stator body (5) are twisted with a twisting tool (11) from an initial position (A) to a final end position (E) such that the free hairpin ends (10) are arranged obliquely to the longitudinal axis (6) of the stator body and the majority of the free hairpin ends (10) are joined to form end pairs (12). Finally, the free hairpin ends (10) of the end pairs (12) are connected to each other. Furthermore, the invention relates to an electric machine (3) for driving a motor vehicle (4) and a motor vehicle (4) with an electric drive system (16).

Description

[0001] The present invention relates to a method for manufacturing a stator winding of a stator of an electric machine for powering a motor vehicle. The invention further relates to an electric machine for powering a motor vehicle and to a motor vehicle with an electric machine of the generic type for powering the motor vehicle.

[0002] Electric motors for powering motor vehicles are known, comprising a stator and a rotor arranged coaxially to the stator and rotatably mounted. The stator has a stator winding made of winding wire.

[0003] A well-known winding type is called a "hairpin winding." A hairpin winding has several so-called "hairpins" arranged in stator slots of a stator body. To create a continuous winding, free hairpin ends are twisted circumferentially, cut to length, and then electrically and mechanically coupled in pairs, for example by welding, brazing, or similar processes.

[0004] The hairpins are either rod-shaped as I-pins or as U-pins with two parallel legs and a common bending area. U-pins have the advantage that, after the hairpins are arranged in the stator body, a winding head is already formed by the bending areas, so that subsequent twisting and joining processes on this side of the stator can be omitted.

[0005] Documents KR 10 2022 0 160 175 A, KR 10 2023 0 005 639 A and DE 10 2022 130 168 A1 disclose various methods for manufacturing stator winding heads, in which the free hairpin ends of several hairpins are first brought together in pairs and then twisted in opposite directions around the circumference of the stator. A tool used for this purpose has several concentric rings that are designed to be rotatable relative to each other. After twisting, the free hairpin ends protrude axially from the stator and can be cut off in a subsequent cutting process.

[0006] Known methods for manufacturing a stator winding head have the disadvantage that, in addition to bending and welding processes, cutting processes are also performed to minimize the winding head's footprint. These cutting processes require the use of a specially designed cutting tool and are therefore particularly time-consuming and expensive. Furthermore, the cutting process results in increased material consumption, as the hairpins must be made longer by the length to be cut. This further increases the manufacturing costs of the stator winding.

[0007] It is therefore an object of the present invention to eliminate, or at least partially eliminate, the disadvantages described above in a stator winding of an electric motor for driving a motor vehicle. In particular, it is an object of the present invention to provide a method for manufacturing a stator winding of an electric motor for driving a motor vehicle, an electric motor for driving a motor vehicle, and a motor vehicle with an electric motor for driving the motor vehicle, which, in a simple and cost-effective manner, have a particularly small installation space requirement.

[0008] The aforementioned problem is solved by the claims. Accordingly, the problem is solved by a method for manufacturing a stator winding of a stator of an electric machine for driving a motor vehicle, comprising the features of independent claim 1; by an electric machine for driving a motor vehicle, comprising the features of dependent claim 9; and by a motor vehicle comprising an electric machine for driving the motor vehicle, comprising the features of dependent claim 10. Further features and details of the invention will become apparent from the dependent claims, the description, and the drawings.Features and details described in connection with the inventive method naturally also apply in connection with the inventive electric machine and the inventive motor vehicle, and vice versa, so that with regard to the disclosure of the individual aspects of the invention, mutual reference is always made or can be made.

[0009] According to a first aspect of the invention, the problem is solved by a method for manufacturing a stator winding of a stator of an electric machine for powering a motor vehicle. The method comprises: - Providing a stator base body with a base body longitudinal axis and a plurality of stator slots, - Arranging hairpins in the stator slots such that hairpin end regions of the hairpins with free hairpin ends protrude from the stator slots on a base body end face of the stator base body, - Twisting the hairpin end areas with a twisting tool from a starting position to a final end position such that the hairpins at the free hairpin ends are arranged obliquely to the longitudinal axis of the base body and the hairpins at the free hairpin ends are joined to form end pairs, and - Connecting the end pairs.

[0010] The provided stator body preferably comprises a stator lamination stack consisting of a plurality of stator lamination disks, for example made of electrical steel or the like, stacked side by side coaxially to the longitudinal axis of the body. The stator lamination disks are preferably coated with an electrically insulating layer, such as enamel or the like, to prevent current flow through the stator body. Stator slots are formed in the stator body. A slot width extends circumferentially around the stator body, a slot depth extends radially from the longitudinal axis of the body, and a slot length extends parallel to the longitudinal axis of the body through the entire stator body, so that the stator slots are open at the end faces of the stator body. The stator slots are bounded radially by the stator body.The stator slots are preferably arranged evenly distributed in the circumferential direction.

[0011] The hairpins are provided as U-pins or I-pins, with the twisting and electrical connection being carried out on one side of the stator body for U-pins and preferably on both sides of the stator body for I-pins. I-pins essentially correspond to the legs of a U-pin. For the sake of simplicity, the legs of the U-pins are each referred to as hairpins within the scope of the invention. The hairpins preferably have a rectangular cross-section. The hairpins can be arranged, for example, by insertion into the stator slots. For example, the hairpins can be held aligned on a holding device and simultaneously inserted into the stator slots. The arrangement of the hairpins in the stator slots is carried out such that the hairpin end regions of the hairpins protrude from the stator slots with free hairpin ends on one end face of the stator body.In I-pins, the hairpins are arranged in the stator slots such that the hairpin end regions protrude from the stator slots with free hairpin ends on both end faces of the stator body. The hairpins are arranged in several radially adjacent layers within the stator slots. According to the invention, for example, four, six, eight, or ten hairpin layers can be provided. The hairpins are preferably made of copper and more preferably have an electrically insulating layer or coating.

[0012] A hairpin end is defined as a section of the hairpin that includes the free end and a portion of the hairpin extending from it. The free end limits the hairpin's length in one direction. It can be created, for example, when cutting a winding wire to length to form the hairpin. Furthermore, the free end can also have a shape other than a straight cut, such as a chamfer, a rounded edge, or the like.

[0013] Before twisting the hairpin end regions, the hairpin end regions are preferably widened, thereby bending them open in a radial direction. For twisting, the twisting tool is preferably brought close to the free hairpin ends and engaged with them. Preferably, the twisting tool is engaged with the free hairpin ends of each hairpin layer. The twisting is preferably carried out such that the free hairpin ends of adjacent hairpin layers are twisted in opposite circumferential directions of the stator base body. According to the invention, the twisting is carried out such that the hairpins are arranged in their final end position. In the final end position, the hairpins at the free hairpin ends are arranged obliquely to the longitudinal axis of the base body. Furthermore, the hairpins at the free hairpin ends are joined together to form end pairs.Preferably excluded from this are hairpins that are provided for connecting the stator winding, for example to power electronics. According to the invention, all of the free hairpin ends can also be joined together to form end pairs. With eight hairpin layers, for example, four end pairs arranged radially next to each other result for the majority of the stator slots; with six hairpin layers, for example, three end pairs result. Preferably, the number of hairpin layers per stator slot is twice the number of end pairs arranged radially next to each other. The widening and / or twisting is preferably carried out by cold forming, preferably at room temperature.

[0014] Finally, the free hairpin ends of the end pairs are connected to each other in pairs, for example by welding, brazing, or similar processes. This ensures that the free hairpin ends of the end pairs are electrically coupled to each other. Thus, a multi-phase stator winding can be created.

[0015] An inventive method for manufacturing a stator winding of an electric motor for powering a motor vehicle has the advantage over conventional methods that a stator winding with a particularly small axial extent can be produced using simple means and in a cost-effective manner. Thus, the stator requires less space in the axial direction than conventional stators. By eliminating the separation process after twisting, the manufacturing of the stator winding is simplified compared to conventional methods and can be carried out more efficiently in terms of time, materials, and costs.

[0016] According to a preferred embodiment of the invention, a method for manufacturing a winding head of an electric motor for powering a motor vehicle can be provided for in such a way that the twisting of the hairpin end sections from the initial position to the final end position is carried out using the same twisting tool. For this purpose, the twisting tool preferably has several receiving areas for each hairpin, which are configured differently. The receiving areas are preferably configured such that the hairpin end section is guided successively by the different receiving areas during the twisting process. This has the advantage that a particularly efficient production of a stator winding is ensured with simple means and in a cost-effective manner.By twisting with only one twisting tool, non-productive times, such as moving away a first twisting tool and bringing in another twisting tool, can be avoided, thus reducing the manufacturing time of the stator winding.

[0017] According to the invention, it is preferred that the twisting of the hairpin end regions from the initial position to the final end position is carried out in a multi-stage process via an intermediate layer, wherein the intermediate layer is formed between the initial position and the final end position. Preferably, the twisting is carried out in a two-stage process. In the second twisting stage, a relative movement of the twisting tool preferably takes place in the axial direction towards the stator base body in order to produce the flattest possible winding head. According to the invention, several intermediate layers can also be provided, so that the twisting can accordingly also be carried out in a three-, four- or multi-stage process. An intermediate layer is understood, for example, to be a state during the forming of the hairpin end regions in which a forming direction of the hairpin end regions changes, for example abruptly.Accordingly, for example, a first section of the hairpin end can be formed between the initial position and the intermediate layer, and a second section of the hairpin end, different from the first, can be formed between the intermediate layer and the final position. This has the advantage that a particularly efficient stator winding can be manufactured using simple and cost-effective means. Furthermore, the multi-stage twisting process reduces the manufacturing time of the stator winding.

[0018] Preferably, the twisting tool is used to first twist the hairpin end sections from the initial position into the intermediate layer. Subsequently, the twisting tool is repositioned at the hairpin end sections, and finally, the hairpin end sections are twisted from the intermediate layer into the final end position. The twisting tool thus preferably has a first receiving area and a second receiving area, which is shaped differently from the first receiving area, for each hairpin end section. The first receiving area preferably forms a common receptacle with the second receiving area. Preferably, the first receiving area is arranged adjacent to the second receiving area, in particular directly adjacent. Preferably, the first receiving area has smaller circumferential dimensions than the second receiving area. The first twisting preferably occurs such that the hairpin end section engages with the first receiving area.Preferably, the hairpin end region is arranged in the first receiving region. The twisting tool is then rotated circumferentially. During the first twist, the second receiving region is preferably not engaged with the hairpin end region. After reaching the intermediate position, the twisting tool is moved towards the hairpin end region such that the hairpin end region engages with the second receiving region. This can, for example, also be done automatically by continuing a movement of the twisting tool according to the first twist. Preferably, the hairpin end region is now arranged in the second receiving region. The twisting tool is then rotated circumferentially, preferably in the same direction as during the first twist. During the second twist, the first receiving region is preferably not engaged with the hairpin end region.The first and second twisting sections differ in that the first and second twisting processes result in different twist formations at the hairpin end. Once the final position is reached, the twisting tool is removed from the hairpin end. This offers the advantage of efficient and cost-effective stator winding production using simple means. Furthermore, the multi-stage twisting process reduces the stator winding production time.

[0019] In a particularly preferred embodiment of the invention, a method may be provided that the twisting tool is repositioned such that, immediately after repositioning, the twisting tool has a greater distance from the stator base body than immediately before repositioning. In other words, the repositioning preferably involves an axial movement of the twisting tool away from the stator base body. Preferably, the hairpin end region is arranged in the first receiving region of the twisting tool before the axial movement. A region of the hairpin end located closer to the stator base body is arranged in the second receiving region, and in this state, there is preferably no physical contact between the second receiving region and the hairpin end region. During the axial movement, the hairpin end region slides out of the first receiving region such that the free hairpin end is now located in the second receiving region.By further rotating the twisting tool circumferentially, the second receiving area is pressed against the free hairpin end, resulting in the second twist. This has the advantage of ensuring particularly efficient stator winding production using simple and cost-effective means. Furthermore, the multi-stage twisting process reduces the stator winding production time.

[0020] Preferably, the twisting process is carried out such that the free hairpin ends roll off the twisting tool between the intermediate layer and the final end position. For this purpose, the free hairpin ends preferably have a rolling contour, for example, a rounded edge or the like, which facilitates the rolling of the hairpin on the twisting tool and prevents it from getting stuck or jerking during the second twist. To prevent the hairpins from slipping off the twisting tool, the twisting tool preferably moves axially towards the stator body during the rolling process. This has the advantage of ensuring a particularly efficient and cost-effective production of a stator winding using simple means. Furthermore, the rolling of the hairpins on the twisting tool allows for the creation of a particularly flat winding head.

[0021] According to a preferred embodiment of the invention, the twisting is carried out such that the hairpin end regions each have a first bending region close to the stator body and a second bending region farther from the stator body, wherein the first bending degree of the first bending region is greater than the second bending degree of the second bending region. A bending region is understood to be a region of the hairpin in which the hairpin is bent in one direction. Preferably, the first bending region and / or second bending region is formed as a kink or a rounded section. The hairpins emerging from the stator slots in the axial direction initially have the first bending region, which can, for example, have an angle between 100° and 140°. Due to the first bending region, the hairpins are bent in the circumferential direction and thus have an extension component in both the axial and circumferential directions.Between the first and second bending sections, the hairpins are preferably not deformed, so that they are straight in this intermediate section. In the second bending section, the hairpins are bent back slightly towards the axial direction. The second bending section has an angle greater than that of the first bending section. Thus, the second bending section is preferably less deformed than the first. For example, the second bending section has an angle between 120° and 170°. After the second bending section, the hairpins therefore have a smaller circumferential extension component and a larger axial extension component than in the intermediate section. The method is preferably carried out such that the second bending section is first completely or at least substantially formed, while the first bending section is only partially formed.The first bending section is then completely produced. This has the advantage of ensuring particularly efficient and cost-effective production of a stator winding using simple means. The production of these bending sections allows for the manufacture of a particularly flat winding head.

[0022] The twisting is particularly preferably carried out such that the free hairpin ends of an end pair are arranged at an angle between 50° and 150° to each other. This means that the free hairpin ends point in opposite circumferential directions and in the same axial direction, thus forming such an angle between the hairpin end sections directly adjoining the free hairpin ends. The angle is particularly preferably between 80° and 120°, for example 100°. This has the advantage that a particularly efficient and cost-effective production of a stator winding is ensured using simple means. By generating such an angle, a particularly flat winding head can be produced.

[0023] According to a second aspect of the invention, the problem is solved by an electric machine for powering a motor vehicle. The electric machine has a stator with a stator winding and a rotor rotatably mounted relative to the stator. According to the invention, the stator winding is produced by a method according to the invention.

[0024] The electric motor according to the invention for driving a motor vehicle offers all the advantages already described in the first aspect of the invention for a method of manufacturing a stator winding of an electric motor for driving a motor vehicle. Accordingly, the electric motor according to the invention has the advantage over conventional electric motors that a stator winding is provided using simple means and in a cost-effective manner, which has a winding head with a particularly small axial extent. Thus, the stator requires less installation space in the axial direction than conventional stators. The elimination of the separation process after twisting simplifies the manufacturing of the stator winding compared to conventional methods and makes it more time-, material-, and cost-efficient.

[0025] According to a third aspect of the invention, the problem is solved by a motor vehicle. The motor vehicle has an electric drive system. According to the invention, the electric drive system for propelling the motor vehicle includes an electric machine according to the invention.

[0026] The motor vehicle according to the invention offers all the advantages already described for a method for manufacturing a stator winding of an electric motor for driving a motor vehicle according to the first aspect of the invention, as well as for an electric motor vehicle for driving a motor vehicle according to the second aspect of the invention. Accordingly, the motor vehicle according to the invention has the advantage over conventional motor vehicles that a stator winding is provided using simple means and in a cost-effective manner, which has a winding head with a particularly small axial extent. Thus, the stator requires less installation space in the axial direction than conventional stators. The elimination of the separation process after twisting simplifies the manufacturing of the stator winding compared to conventional methods and makes it more time-, material-, and cost-efficient.

[0027] An electric machine according to the invention, a motor vehicle according to the invention, and a method according to the invention for manufacturing a stator winding of a stator of an electric machine for driving a motor vehicle are explained in more detail below with reference to the drawings. The drawings schematically show: Fig. 1. In a perspective view, a stator according to the state of the art, Fig. 2 in a sectional view a first state during the execution of a preferred embodiment of a method according to the invention, Fig. 3 in a sectional view a second state during the execution of the preferred embodiment of a method according to the invention, Fig. 4 in a sectional view a third state during the execution of the preferred embodiment of a method according to the invention, Fig. 5 in a sectional view a fourth state during the execution of the preferred embodiment of a method according to the invention, Fig. 6 in a sectional view a fifth state in the execution of the preferred embodiment of a method according to the invention, Fig. 7 in an exploded view an electric machine according to a preferred embodiment of the invention, Fig. 8 in a side view a preferred embodiment of a motor vehicle according to the invention, and Fig. 9 in a flowchart a preferred embodiment of a method according to the invention.

[0028] Elements with the same function and mode of operation are in the Fig. Numbers 1 to 9 are each labelled with the same reference symbols.

[0029] In Fig. Figure 1 shows a stator 2 according to the prior art, schematically depicted in a perspective view. The stator 2 has a stator body 5 that extends along and around a longitudinal axis 6. A plurality of stator slots 7 are formed in the stator body 5. Several hairpins 8 are arranged radially in several slots within the stator slots 7. Hairpin end sections 9 of the hairpins 8, with free hairpin ends 10, project axially from the stator slots 7 and are twisted such that the free hairpin ends 10 are parallel to the longitudinal axis 6 of the stator body. The hairpin end sections 9 are grouped into end pairs 12 and connected to each other in pairs. Thus, a stator winding 1 is formed by the hairpins 8. Such a stator 2 has particularly large dimensions in the axial direction.

[0030] Fig. Figure 2 schematically shows the first state during the execution of the preferred embodiment of the method according to the invention in a sectional view. The first state is an initial position A. In the initial position A, hairpins 8 are arranged in stator slots 7 of a stator base body 5 such that hairpin end regions 9 of the hairpins 8 project axially from the stator slots 7. A section of the hairpin end regions 9 with a free hairpin end 10 of the hairpins 8 is arranged in a first receptacle 17 of a twisting tool 11. A second receptacle 18 of the twisting tool 11, which has no function in the initial position A, is arranged between the first receptacle 17 and the stator base body 5. In the subsequent twisting process, the twisting tool 11 is rotated circumferentially around the stator base body 5 such that the hairpin end regions 9 are plastically deformed.

[0031] In Fig. Figure 3 schematically illustrates the second state in the execution of the preferred embodiment of the method according to the invention in a sectional view. In the second state, the hairpin end regions 9 are in an intermediate position Z. In the intermediate position Z, the hairpins 8 at the free hairpin end 10 remain oriented in the axial direction, while a region of the hairpins 8 arranged between the twisting tool 11 and the stator base body 5 is oriented obliquely to the longitudinal axis 6 of the base body. In the second state, the first twisting process is completed, and the free hairpin end 10 remains within the first receptacle 17, allowing the twisting tool 11 to be repositioned.

[0032] Fig. Figure 4 schematically shows the third state during the execution of the preferred embodiment of the method according to the invention in a sectional view. The third state occurs after the first twisting during the repositioning of the twisting tool 11. Compared to the second state, the twisting tool 11 is moved axially away from the stator base body 5 such that the free hairpin end 10 is now arranged within the second receptacle 18.

[0033] In Fig. Figure 5 is the fourth state in the execution of the preferred embodiment of the method according to the invention, schematically depicted in a sectional view. The fifth state is reached by rotating the twisting tool 11 circumferentially such that a wall of the second receptacle 18 comes into contact with the hairpin 8 at the free hairpin end 10. Now, in a second twisting action, the twisting tool 11 can be moved with a movement component in the axial direction such that the hairpin end region 9 is bent axially towards the stator base body 5.

[0034] Fig. Figure 6 schematically shows the fifth state in the execution of the preferred embodiment of the method according to the invention in a sectional view. In the fifth state, the hairpins 8 are arranged in a final end position E. In the final end position E, the hairpins 8 have a first bending region 13 directly at the end of the stator groove 7 and a second bending region 14 near the free hairpin end 10, with a bending direction opposite to that of the first bending region 13. The first bending region 13 has a larger bending angle than the second bending region 14. Thus, the hairpins 8 have an orientation oblique to the axial direction between the second bending region 14 and the free hairpin ends 10. Subsequently, the twisting tool 11 can be removed from the hairpins 8 and end pairs 12 (see Figure 6) can be removed. Fig. 7) The hairpins 8 can be connected to each other, for example by welding, brazing or the like. A stator 2 (see below) Fig. 7) with a stator winding 1 according to the invention has significantly smaller dimensions in the axial direction than a stator 2 according to the prior art.

[0035] In Fig. Figure 7 shows a schematic exploded view of the electric machine 3 according to the preferred embodiment of the invention. The electric machine 3 has a stator 2 with a stator winding 1 according to the invention. The stator winding 1 is formed by hairpins 8 which are arranged in stator slots 7 of a stator body 5, wherein hairpin end pairs 12 of the hairpins 8 are connected to each other, for example by welding or brazing.

[0036] Furthermore, the electric machine 3 has a rotor 15 which can be rotatably arranged within the stator 2 about a longitudinal axis 6 of the base body. In addition, the electric machine 3 has a multi-part machine housing 19 to protect the stator 2 and the rotor 15 from external influences and to facilitate the mounting of the electric machine 3 in a motor vehicle 4. For the targeted energizing of the stator 2 to operate the electric machine 3, the electric machine 3 has power electronics 20 with its own housing. The power electronics 20 are electrically connected to the stator 2.

[0037] Fig. Figure 8 schematically shows a preferred embodiment of a motor vehicle 4 according to the invention in a side view. The motor vehicle 4 has an electric drive system 16 with an electric machine 3 according to the invention and a traction battery 21 for storing and providing electrical energy for operating the electric machine 3.

[0038] In Fig. Figure 9 schematically illustrates the preferred embodiment of the method according to the invention in a flowchart. In a first process step 100, a stator base body 5 is provided. The stator base body 5 extends around a base body longitudinal axis 6 and along the base body longitudinal axis 6, and is thus approximately hollow cylindrical in shape. Stator grooves 7 are formed in the stator base body 5, which extend parallel to the base body longitudinal axis 6 and are open towards the base body longitudinal axis 6 and in the axial direction.

[0039] In a second process step 200, hairpins 8 are arranged in the stator slots 7. This is preferably done by inserting the hairpins 8 axially into the stator slots 7. The hairpins 8 are arranged in several slots 7 with respect to a radial slot depth of the stator slots 7. Furthermore, the hairpins 8 are arranged in the stator slots 7 such that hairpin end regions 9 of the hairpins 8 with free hairpin ends 10 protrude from the stator slots 7 on at least one end face of the stator body 5. Thus, the hairpins 8 are arranged in an initial position A.

[0040] In a third process step 300, the hairpin end regions 9 are twisted by a twisting tool 11. Here, the hairpin end regions 9 are preferably first twisted into an intermediate position Z and then, in a second twist, into a final end position E. Between the first and second twists, the twisting tool 11 can also be repositioned at the free hairpin end 10. In the final end position E, the hairpins 8 at the free hairpin ends 10 are arranged obliquely to the longitudinal axis 6 of the base body, and the hairpins 8 at the free hairpin ends 10 are joined to form end pairs 12. In a fourth process step 400, the end pairs 12 are joined, for example, by welding, brazing, or the like. Reference symbol list 1 Stator winding 2 Stator 3 Electric machine 4 Motor vehicle 5 Stator base body 6 Base body longitudinal axis 7 Stator slot 8 Hairpin 9 Hairpin end area 10 free hairpin ends 11 Twisting tools 12 End pair 13 first bending area 14 second bending area 15 Rotor 16 electric drive system 17 first recording 18 second recording 19 machine housings 20 Power Electronics 21 Traction battery A Starting point E final end position Z Interlayer 100 first procedural action 200 second procedural action 300 third procedural action 400 fourth procedural action QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] KR 10 2022 0 160 175 A

[0005] KR 10 2023 0 005 639 A

[0005] DE 10 2022 130 168 A1

[0005]

Claims

[1] Method for manufacturing a stator winding (1) of a stator (2) of an electric machine (3) for driving a motor vehicle (4), comprising: - Providing a stator base body (5) with a base body longitudinal axis (6) and a plurality of stator slots (7), - Arranging hairpins (8) in the stator slots (7) such that hairpin end regions (9) of the hairpins (8) with free hairpin ends (10) protrude from the stator slots (7) on a base body end face of the stator base body (5), - Twisting the hairpin end regions (9) with a twisting tool (11) from an initial position (A) to a final end position (E) such that the hairpins (8) at the free hairpin ends (10) are arranged obliquely to the longitudinal axis (6) of the base body and the hairpins (8) at the free hairpin ends (10) are joined to form end pairs (12), and - Connecting the end pairs (12). [2] Method according to claim 1, characterized by, that the twisting of the hairpin end areas (9) from the initial position (A) to the final end position (E) is carried out with the same twisting tool (11). [3] Method according to claim 1 or 2, characterized by , that the twisting of the hairpin end areas (9) from the initial position (A) to the final end position (E) is carried out in a multi-stage process via an intermediate layer (Z), wherein the intermediate layer (Z) is formed between the initial position (A) and the final end position (E). [4] Method according to claim 3, characterized by , that the hairpin end areas (9) are first twisted from the starting position (A) to the intermediate position (Z) using the twist tool (11), then the twist tool (11) is repositioned at the hairpin end areas (9), and finally the hairpin end areas (9) are twisted from the intermediate position (Z) to the final end position (E). [5] Method according to claim 4, characterized by, that the repositioning of the twisting tool (11) is carried out in such a way that the twisting tool (11) has a greater distance to the stator base body (5) immediately after repositioning than immediately before repositioning. [6] Method according to any one of claims 3 to 5, characterized by , that the twisting is carried out in such a way that the free hairpin ends (10) roll off between the intermediate layer (Z) of the final end position (E) on the twisting tool (11). [7] Method according to any of the preceding claims, characterized by , that the twisting is carried out such that the hairpin end regions (9) each have a first bending region (13) close to the stator body (5) and a second bending region (14) far from the stator body (5), wherein a first bending degree of the first bending region (13) is greater than a second bending degree of the second bending region (14). [8] Method according to any of the preceding claims, characterized by, that the twisting is carried out such that the free hairpin ends (10) of an end pair (12) are arranged at an angle between 50° and 150° to each other. [9] Electric machine (3) for driving a motor vehicle (4), comprising a stator (2) with a stator winding (1) and a rotor (15) rotatably mounted to the stator (2), characterized by , that the stator winding (1) is produced by a method according to one of the preceding claims. [10] Motor vehicle (4) comprising an electric drive system (16), characterized by , that the electric drive system (16) for driving the motor vehicle (4) comprises an electric machine (3) according to claim 9.

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