Stator for an electric machine of a traction drive of a motor vehicle

Abstract

The invention relates to a stator (10) for an electric machine of a traction drive of a motor vehicle, wherein the stator (10) comprises an annular stator core (12) having a plurality of grooves (30), wherein a plurality of plug-in windings (20) are provided, which are designed as hairpins and are arranged in the grooves (30) so as to pass one another in the form of hairpin winding technology, forming a stator winding (22), wherein the position of the plug-in windings (20) in the grooves (30) is defined by the radial layer of the plug-in winding (20) and the groove position (16) of the groove (30), and wherein, in each groove, an uneven number of layers of the plug-in windings (20) are arranged above one another in the radial direction of the stator core (12), wherein the uneven number ≥ 3, wherein the bar winding technology is designed in such a way that the plug-in windings (20) form a current path (28) running continuously from a first axial end of the stator core (12) to a second axial end of the stator core (12) arranged axially opposite the first axial end, and back again, in such a way that, at the first axial end, the current path (28) is guided in a radially outer layer with a groove jump but without a layer jump, the current path (28) subsequently runs in at least one radially middle layer with a groove jump and layer jump towards the second axial end into a radially inner layer, wherein, at the second axial end, the current path (28) is guided in the radially inner layer with a groove jump but without a layer jump, the current path (28) subsequently runs in at least one radially middle layer with a groove jump and a layer jump towards the first axial end into the radially outer layer, wherein the current path (28) is opened at a top end (24) of a plug-in winding (20) by opening the plug-in winding (20), in order to form connections (26) of the current path (28).

Description

[0001] Description

[0002] Stator for an electric machine of a traction drive of a motor vehicle

[0003] The present invention relates to a stator for an electric machine of a traction drive for a motor vehicle. The present invention relates in particular to a stator having a particularly advantageous winding in bar winding technology. The present invention further relates to a traction drive for an electrically powered motor vehicle comprising such a stator, and to the use of the advantageous bar winding technology for forming a stator winding for a traction drive of an electrically powered motor vehicle.

[0004] Electric motors are a major focus of current developments. These typically consist of a stator and a rotor driven by it. To drive the rotor, the stator includes a current-carrying stator winding. Currently, highly automated stator bar windings, such as so-called bar winding windings, are being produced. These windings feature plug-in turns located in slots on the stator or stator core. Stator windings are usually designed with an even number of layers of plug-in turns in these slots.

[0005] For example, a winding number of 20 turns can offer advantages. However, manufacturing a winding with 20 turns is not trivial. So far, this is usually achieved using a 10-layer winding with four parallel paths. This winding topology is complex to manufacture, however, so its use is limited. Furthermore, the ten layers mean that this winding quickly reaches its thermal limit due to the small cross-section of the individual layers, thus limiting the maximum power output of the drive system.

[0006] DE 10 2022 120 729 A1 describes a hairpin stator comprising a kem, slot positions, and hairpin wires. The kem has a first side and a second side. The slot positions are configured circumferentially on the kem to form M radially adjacent slot position layers, where M is an odd number greater than or equal to 5. The hairpin wires are configured and connected in the slot positions to form a plurality of windings. The hairpin wires comprise a plurality of first U-shaped wires arranged radially in an outermost slot position layer and a plurality of second U-shaped wires arranged radially in an innermost slot position layer. Each first U-shaped wire comprises a U-shaped section located at the outermost slot position layer and projecting from the first side of the kem.Every second U-shaped wire contains a U-shaped section that is located at the innermost slot position layer and protrudes from the second side of the kem.

[0007] However, existing solutions can be further improved with regard to bar winding technology. In particular, there is still a need for improvement concerning a simple method for creating a bar winding with highly adaptable numbers of turns.

[0008] It is therefore an object of the present invention to provide a solution by which at least one disadvantage of the prior art can be overcome, at least partially. In particular, it is an object of the present invention to provide a solution by which a rod winding can be improved, especially with regard to the variability of the number of turns.

[0009] The problem is solved by a stator for an electric machine of a traction drive of a motor vehicle having the features of claim 1. The problem is further solved by use with the features of claim 9 and by a traction drive having the features of claim 10. Preferred embodiments of the invention are described in the dependent claims, in the description or the figures, wherein further features described or shown in the dependent claims or in the description or the figures may, individually or in any combination, constitute an object of the invention unless the context clearly indicates otherwise.

[0010] A stator for an electric machine of a traction drive of a motor vehicle is described, wherein the stator comprises an annular stator core with a plurality of slots, wherein a plurality of plug-in windings are provided, which are designed as hairpins and are arranged passing one another in the slots in a hairpin winding technology to form a stator winding, wherein the position of the plug-in windings in the slots is defined by the radial position of the plug-in winding and the slot position, and wherein in each slot an odd number of layers of plug-in windings are arranged one above the other in the radial direction of the stator core, wherein the odd number is > 3, wherein the bar winding technology is designed such that the plug-in windings form a current path.the current path runs continuously from a first axial end of the stator core to a second axial end of the stator core arranged axially opposite the first axial end and back again, such that at the first axial end the current path is guided in a radially outer position with a slot step but without a position step, following at least one radially middle position with a slot step and a position step to the second axial end in a radially inner position, wherein at the second axial end the current path is guided in the radially inner position with a slot step but without a position step, following at least one radially middle position with a slot step and a position step to the first axial end in the radially outer position, wherein the current path is opened at a head end of a plug-in winding by opening the plug-in winding to form connections of the current path.

[0011] Such a stator offers significant advantages over prior art solutions.

[0012] This document describes a stator for an electric machine of a vehicle traction drive. The stator described here is part of a stator-rotor assembly, which in turn is part of an electric machine or electric motor. In a manner known per se, the rotor is driven by the stator to, for example, drive a shaft or a wheel of a vehicle. For this purpose, the stator has a stator winding to interact with a magnetic or magnetizable element of the rotor and thereby set the rotor in rotation.

[0013] More precisely, the stator comprises an annular stator core that surrounds a rotor receptacle, typically cylindrical, for holding the rotor. The stator, or rather the stator core, includes a multitude of slots, which define the positions of slots for arranging the stator winding.

[0014] In a rotor described as an internal rotor, for example, the slot positions are preferably arranged axially on an inner surface of the stator core that is oriented radially inwards and spaced apart from each other in the circumferential direction of the stator core. The circumferential direction thus refers to the stator core. The slot positions preferably always have the same distance from each other to ensure a uniform distribution of slot positions along the inner circumference. This ensures that the winding placed in the slot positions can interact effectively and uniformly with the rotor, independent of the rotor's rotation, and thus drive it. Furthermore, winding elements arranged in the slot positions can face the rotor.

[0015] For the formation of the stator winding, a plurality of plug-in turns are provided, which are arranged in the slot positions or passing each other in the slots using a hairpin winding technology. The hairpin winding technology, as a rod winding technology, is generally known to those skilled in the art and, in contrast to a conventional coil winding technique, is based on plug-in turns that are inserted into the slot positions of the stator core. According to the invention, the plug-in turns are designed as so-called hairpins, which have a U-shape and can, in particular, be formed as correspondingly shaped flat copper wires. The hairpins have a leg end at which the legs of the hairpin are located and also have a head end at which the two legs are connected to each other or merge into one another.

[0016] When using hairpins, the legs of the plug-in windings are located at one axial end of the stator core, also known as the hairpin end or weld end, and the section connecting the legs, i.e., the head section, is located at the axial end of the stator core opposite the leg ends. To form a winding, the leg ends are twisted and welded together in a suitable manner around the circumference of the stator core.

[0017] It is further provided that in each slot position, an odd number of layers of the plug-in windings are arranged one above the other in the radial direction of the stator core, wherein the odd number is greater than 3. In other words, at least three plug-in windings, in particular exactly three plug-in windings or exactly five plug-in windings, are arranged one above the other in the radial direction, or in other words, side by side, in the slot positions or in the slots of the stator core. More than three plug-in windings may also be present, provided that an odd number of plug-in windings is present. Thus, for example, three, five, seven, nine, eleven, or more plug-in windings may be present. However, it may be preferred that the total number of layers of plug-in windings located in the slot positions is limited to a number of less than 13, for example, less than 11, preferably less than 9.For example, the total number of layers of plug-in windings located in the slot positions in the radial direction can thus be in a range from > 3 to < 13, where, as described above, there is an odd number. In the circumferential direction of the stator core, preferably only one leg of a plug-in winding is located in a slot position, or in other words, the legs of a plug-in winding are always located in different slot positions.

[0018] The bar winding technology, i.e., the arrangement, connection, and formation of the hairpins, is designed such that the plug-in windings form a current path that runs continuously from a first axial end of the stator core to a second axial end of the stator core located axially opposite the first axial end, and back again. This can occur once or, preferably, multiple times, so that the current path connects the two axial ends of the stator core once or, preferably, multiple times without interruption.

[0019] This is designed such that at the first axial end, the current path is guided in a radially outer position, i.e., in the outermost radial position, with a slot step but without a layer step, thus passing through two different slots in one radial position. Subsequently, the current path runs in at least one radially middle position with a slot step and a layer step. This can occur in a middle position, i.e., a position between the radial end positions, or in multiple radially middle positions. In a three-layer winding, there is thus one radially middle position, while in a five-layer winding there are three radially middle positions. If more than one radially middle position is present, they are preferably all designed with the same layer step and slot step of the current path.

[0020] In this way, the current path to the second axial end runs into a radially inner position, i.e., the radially innermost position. In this position, the current path essentially corresponds to the first radially outer position, namely with a slot step but without a position step. Subsequently, the current path runs back to the first axial end of the stator core, passing through at least one or more intermediate positions with a slot step and a position step to the first axial end in the radially outer position, as described above.

[0021] Accordingly, it can preferably be provided that the current path runs in the radially inner position and in the radially outer position in the same way, and equally on the path from the first axial end to the second axial end and back. In particular, this embodiment makes it advantageously possible for the current path to have no point of intersection, but rather for the respective areas to run strictly adjacent to each other.

[0022] In the described stator, the current path is further provided that it is opened at one end of a plug-in winding by opening the winding to form connections for the current path. Accordingly, the connections for forming the coil or for energizing the current path are designed by opening hairpins at their end and thus connecting them to a power source. This can, in principle, be implemented using known manufacturing processes.

[0023] A stator with a previously described bar winding technology can offer significant advantages over state-of-the-art solutions.

[0024] Because the connections are formed by opening hairpins, there is a great deal of freedom in the arrangement of the connections. This allows a described stator with given specifications to be compatible with a wide variety of applications and spatial as well as electronic requirements. This high degree of flexibility in application makes it highly adaptable and allows for the easy implementation of corresponding customer requirements.

[0025] Furthermore, it is fundamentally possible to achieve a particularly variable number of turns without complex guidance of the plug-in windings relative to each other, and thus without a complex geometry of the plug-in windings, and also with welding patterns simplified compared to the prior art. The winding topology can thus be significantly simplified compared to the prior art, so that even numbers of turns that were previously impossible or very difficult to produce can be easily achieved. According to the invention, this also enables mass production of windings that were previously impossible or not economically viable. The variability and adaptability of the winding can thus be significantly improved.

[0026] Furthermore, according to the invention, the cross-sections of the respective plug-in windings can be increased compared to the cross-sections of the prior art, even with previously complex numbers of turns. This reduces the thermal stress on the winding and, consequently, on the stator. This enables higher power output, which further improves the variability of the electric motor designed with such a stator. Moreover, thermal resistance can be improved, which can prevent or at least reduce damage and service failures caused by thermal influences.

[0027] In principle, the range of applications is very broad, allowing for the configuration of 400V or even 800V systems, which further improves flexibility. For example, spotlights in the 110 to 150 kW range can also be implemented.

[0028] Furthermore, it can be advantageous that the plug-in windings only need to be welded on the welding side and not in the winding head. This allows the welding process to be carried out without complex procedures, which significantly simplifies manufacturing.

[0029] Furthermore, the stator, particularly with regard to its axial length, can be designed to be extremely compact. This is made possible by a winding head with very little axial space, which is achieved through the arrangement and design of the plug-in windings described above. Moreover, the winding head no longer requires free ends, for example, axially aligned ends with plug-in windings of different lengths, which, according to the prior art, serve as weld contacts. This, too, can reduce the axial length of the stator according to the invention.

[0030] The aforementioned advantages thus arise particularly with a mechanically straightforward design of the winding. Furthermore, this makes it possible to easily achieve odd numbers of windings on the welding side or at the welding end.

[0031] Preferably, the current path, with the exception of the terminals, can form a completely closed current path. In this configuration, the plug-in windings are connected to each other in such a way as to create a closed current path, except for the open head areas or head ends of the hairpins. This allows for very precise stator operation. Furthermore, the winding technology can be kept very simple, which can reduce manufacturing effort and costs.

[0032] It may be preferable for all existing layer transitions to each form a layer transition of 1. In this configuration, routing the current path through the winding head can be particularly space-saving. This allows the coil to be especially efficient and the stator to be designed with very little installation space, enabling its use even in spatially limited areas. Furthermore, the stator can deliver high power.

[0033] In a further preferred embodiment, the current path can be routed without any points of intersection with the current path. In this embodiment, the plug-in windings can thus be routed particularly simply and without high complexity. This embodiment can also keep the effort and costs of manufacturing the winding and thus the stator low.

[0034] It may be further preferred that the rod winding technology is designed such that the plug-in windings form a plurality of current paths which run continuously from a first axial end of the stator core to a second axial end of the stator core arranged axially opposite the first axial end and back again, such that at the first axial end the current paths are guided in a radially outer position with a slot step but without a position step, following at least one radially middle position with a slot step and a position step to the second axial end in a radially inner position, wherein at the second axial end the current paths are guided in the radially inner position with a slot step but without a position step, following at least one radially middle position with a slot step and a position step to the first axial end in the first radial position.wherein the current paths are each opened at one end of a plug-in turn by opening the plug-in turn to form connections of the current paths.

[0035] In this configuration, there are multiple current paths, all of which are appropriately designed. Specifically, the current paths can form three phases, with each phase potentially containing two sub-phases. Accordingly, the stator can be configured with six such current paths, which may be almost identical or identical except for the position of the terminals. Thus, the stator as a whole, including a three-phase stator, can be designed with the advantages described above.

[0036] For the formation of the windings, it can also be advantageous for the plug-in turns to have at least two different winding patterns at their welded end on the winding head. The winding patterns at the welded end of the plug-in turns can be formed in a manner known per se, in particular by twisting and welding the legs of the plug-in turns.

[0037] In a first winding pattern, the first insertion turns can be arranged in a radially inner or radially outer position. According to the first winding pattern, the first insertion turns are formed without a step in position. Accordingly, both legs of the first insertion turns are in the same radial position at the weld end, i.e., in the same position within the groove or groove position. This further clarifies that the first insertion turns are only present in the radially innermost or radially outermost position, and thus no second insertion turns are present radially inside or radially outside the first insertion turns.

[0038] In the second winding pattern, second plug-in windings are preferably provided, which are not arranged at the radially inner or radially outer position where the first plug-in windings are located, but can be arranged in the further layers of the respective groove positions. It is further preferred that the second plug-in windings have a layer jump or are designed with a layer jump. A layer jump of 1, i.e., a change of one radial position, is particularly preferred. For example, in the radial direction, one leg can be the second position from the radial outside and the other leg the third position from the radial outside, with respect to the intended number of layers or plug-in windings.

[0039] Due to the overall odd number of layers, it may be preferred that a suitable quantity of second plug-in turns are present in an even number and that the first plug-in turn is located in one layer, the radially inner layer or the radially outer layer.

[0040] The first winding, or windings, are arranged in a radially inner or radially outer position within the groove. In this configuration, the design of the first windings can be particularly simple, as they can be easily shaped to guide or avoid the second windings or other first windings. This allows for a less complex winding topology for the first windings, essentially independent of the second windings. The winding design and, furthermore, the implementation of the invention in existing systems can thus be further simplified. A radially outer position refers to the outermost position of the winding layers. Similarly, a radially inner position refers to the innermost position of the winding layers.

[0041] In an internal rotor, the radially outer position of the first windings is the preferred arrangement for the first windings, since the first windings in the winding head are usually formed in two layers in the radial direction of the stator and thus exist side by side in the position of two layers. This prevents the winding head of the first windings from projecting too far radially inwards, which could hinder the rotor's placement within the stator cavity. Similarly, it is advantageous to provide the radially inner position of the first windings in an external rotor.

[0042] In principle, the first winding pattern can also be present in the radially inner and radially outer positions. Regarding the two-layer design of the first connecting threads, it should be noted that this two-layer design is formed by the position in which the first connecting threads are arranged in the groove, and the second layer forms a pseudo-layer, which arises from the fact that the first connecting threads are guided along each other in a radial direction, but this pseudo-layer is not provided in a respective groove.

[0043] In other words, in the area of ​​the winding head, i.e., the area where the leg ends of the first plug-in turns are twisted circumferentially around the stator, the first plug-in turns are designed to be formed in sections with different, but preferably adjacent, radial positions. In other words, the first plug-in turns in the area of ​​the winding head are deflected, at least section by section, to a radius of deviation that differs from the respective radial position of the first plug-in turns in the slot position, so that the first plug-in turns in the winding head run in a first radial position in one section and in a second radial position, different from the first, in another section.

[0044] This allows the stator to be designed in a simple and space-saving manner in the axial direction. Accordingly, it can be characteristic that the first windings, although they do not exhibit a step change in slot positions, are guided in the radial position of two different, particularly adjacent, layers in the area of ​​the winding head. This allows adjacent first windings to be preferentially guided along one another.

[0045] Preferably, the threaded connections at their weld end can be formed in only the first or the second thread pattern in a single layer. In this configuration, the formation of the thread can be particularly simple, and complex threading technologies can be avoided.

[0046] Preferably, the first plug-in windings in adjacent slot positions can be formed, and in particular bent, in opposite circumferential directions. This represents a departure from conventionally used bending patterns and also from the second plug-in windings in the described stator. In this embodiment, however, it becomes possible to guide the first plug-in windings along adjacent first plug-in windings in a space-saving manner by using the generated pseudo-position. Furthermore, it is preferably possible for the legs to be twisted or wound in opposite directions, which can enable a space-saving arrangement.

[0047] It may be further preferred that the first plug-in windings are formed radially, in particular bulged radially, with a receiving space to guide first plug-in windings along adjacent first plug-in windings in a way that avoids them, in particular to guide the opposing first plug-in coils along them as described above. In this embodiment, it becomes clear that the first plug-in windings are designed to be guided along adjacent first plug-in windings and thus allow for a free design of the first plug-in windings. The invention can therefore be implemented essentially based on the design of the first plug-in windings, which demonstrates the simplicity of the construction and the ease of implementation in existing systems. The radial shaping, in particular the bulge, then forms the pseudo-position of the first plug-in windings.

[0048] The preferred configuration for this design is again the aforementioned radially inner and / or outer position, or the innermost position (i.e., closest to the air gap) or the outermost position (i.e., located at the bottom of the groove). This position of the former is particularly advantageous because it allows the sections of the associated plug threads running in the air to pass each other without colliding with other plug threads, especially the second plug threads.

[0049] For the appropriate formation of the receiving space, it can be advantageous if the first threaded connections are shaped in such a way that they extend out of an axial plane and extend comparatively strongly radially inwards or outwards, in order to be guided along adjacent first threaded connections in the space thus obtained.

[0050] It may be further preferred that the rod winding technology produces a number of turns of 10, 14, 15, 18, 20, 21, 27, 28, 36, 40, preferably 20. In particular, such numbers of turns were usually only achievable in a complex and economically viable way in the prior art, so that the advantages of the present invention can be particularly pronounced in this embodiment.

[0051] Preferably, the stator can have at least one of a total number of slot positions of 72, 54, or 48 and a total number of poles of 8 or 6. It has been shown that such configurations find particularly widespread application, especially in the field of e-mobility, and that a particularly advantageous variability with regard to the number of turns is also possible with such configurations. The total number of slot positions and the total number of poles can, in principle, be combined arbitrarily as mentioned above. In an exemplary embodiment, the stator can have a total of 48 slot positions and a total number of poles of 8.

[0052] Regarding further technical features or advantages of the stator, reference is made to the description of its use, the traction drive, the figures, and the description of the figures.

[0053] The use of a bar winding technology for forming a stator winding for a stator of a traction drive of an electrically powered motor vehicle is further described, wherein the stator comprises an annular stator core with a plurality of slots, wherein a plurality of plug-in turns are provided which are designed as hairpins and are arranged passing each other in the slots in a hairpin winding technology to form a stator winding, wherein the position of the plug-in turns in the slots is defined by the radial position of the plug-in turn and the slot position, and wherein in each slot an odd number of layers of plug-in turns are arranged one above the other in the radial direction of the stator core, wherein the odd number is > 3, wherein the bar winding technology is designed such that the plug-in turns form a current path.the current path runs continuously from a first axial end of the stator core to a second axial end of the stator core arranged axially opposite the first axial end and back again, such that at the first axial end the current path is guided in a radially outer position with a slot step but without a position step, following at least one radially middle position with a slot step and a position step to the second axial end in a radially inner position, wherein at the second axial end the current path is guided in the radially inner position with a slot step but without a position step, following at least one radially middle position with a slot step and a position step to the first axial end in the radially outer position, wherein the current path is opened at a head end of a plug-in winding by opening the plug-in winding to form connections of the current path.

[0054] A previously described rod winding technology or the described winding can offer significant advantages over solutions from the prior art.

[0055] In principle, it is possible to create a particularly variable number of turns without complex guidance of the plug-in windings relative to each other, and thus without a complex geometry of the plug-in windings, and furthermore with welding patterns simplified compared to the prior art. The winding topology can thus be significantly simplified compared to the prior art, so that even numbers of turns that were previously impossible or very difficult to produce can be easily achieved. According to the invention, this also enables mass production of windings that were previously impossible or not economically viable. The variability and adaptability of the winding can thus be significantly improved.

[0056] Furthermore, according to the invention, the cross-sections of the respective plug-in windings can be increased compared to the cross-sections of the prior art, even with previously complex numbers of turns. This reduces the thermal load on the winding and, consequently, on the stator. This enables higher power output, which further improves the versatility of the electric motor designed with such a stator.

[0057] Finally, a suitably manufactured stator can be highly adaptable.

[0058] Regarding further technical features or advantages of use, reference is made to the description of the stator, the traction drive, the figures, and the description of the figures.

[0059] A traction drive for an electrically powered motor vehicle is further described, comprising an arrangement of a rotor and a stator, wherein the stator is designed as described above. The traction drive thus comprises an arrangement of a rotor and a stator in a manner known per se. The stator is designed as described above and has a stator winding that acts on the rotor. The rotor is accordingly arranged in a rotor receptacle of the stator and can be set in rotation by the stator. This allows the rotor to drive an axle or a wheel of an electrically powered motor vehicle.

[0060] An electrically powered motor vehicle can be understood to mean, for example, a purely electric motor vehicle or a hybrid vehicle.

[0061] The design of the stator and, in particular, the winding technology used make it possible to achieve the aforementioned advantages, especially with regard to improved variability in terms of the number of turns as well as reduced thermal stress.

[0062] Regarding further technical features or advantages of the traction drive, reference is made to the description of the stator, its use, the figures, and the description of the figures.

[0063] The invention is further explained below with reference to the figures, whereby one or more features of the figures, individually or in combination, can constitute a feature of the invention. Furthermore, the figures are to be considered merely exemplary and in no way limiting.

[0064] Fig. 1 shows details of a stator according to an embodiment of the present invention at a first axial end of the stator;

[0065] Fig. 2 shows a winding scheme for a stator according to a further embodiment of the present invention; and

[0066] Fig. 3 shows details of a stator according to an embodiment of the present invention at a second axial end of the stator.

[0067] Figure 1 shows in detail a stator 10 for an electric machine of a traction drive for a motor vehicle. The stator 10 comprises an annular stator core 12, which includes an internal rotor receptacle 14 for receiving a rotor (not shown) that can be designed in a conventional manner. The stator core 12 comprises a plurality of slots 30 in slot positions 16, particularly in the region of its inner circumference 18, which, when the rotor is arranged in the rotor receptacle 14, thus face the rotor. The slot positions 16 are parallel in the axial direction and are preferably evenly spaced.

[0068] In the slot positions 16, a plurality of plug-in windings 20 are arranged, which are formed by first plug-in windings 20a and second plug-in windings 20b, as shown in Figure 3. Figure 1 shows in particular the head end 24 of the plug-in windings 20, which are configured as hairpins. In principle, the plug-in windings 20 in the slot positions 16 are arranged passing each other in a bar winding technology, forming a stator winding 22. Figure 1 further indicates that in each slot position 16, an odd number of layers of plug-in windings 20 are arranged one above the other in the radial direction of the stator core 12.

[0069] Figure 1 further shows that by opening the plug-in windings 20, which are designed as hairpins, connections 26 are formed at the head end 24 of the hairpins. These can initially exist as freestanding sections of the plug-in windings 20 and subsequently be energized by connecting them to a voltage source.

[0070] Figure 2 shows details of the stator winding 22, and in particular the winding pattern of the stator winding 22. Specifically, a current path 28 formed by plug-in turns 20 and leading through the corresponding slots 30 is shown, with particular emphasis on the current path 28 of one phase (U) and, in this case, a partial phase. The current paths 28 of the other phases V, W, and the other partial phases follow the same pattern, but are not shown for clarity.

[0071] The X-axis shows the slot positions 16, with a total of 48 slot positions provided in the embodiment according to Figure 2. The Y-axis shows the radial positions (L1 to L5), where L1 represents the radially innermost position and L5 the radially outermost position. The bold areas indicate continuous connections, and the dashed areas indicate interconnected or twisted areas. In detail, the bar winding technology is designed such that the plug-in turns 20 form a current path 28 that runs continuously from a first axial end of the stator core 12 to a second axial end of the stator core 12 arranged axially opposite the first axial end and back again, such that at the first axial end, as shown in Figure 1 at the head end 32, the current path 28 is guided in a radially outer position with a slot step but without a position step.The current path 28, following at least one radially central position with a groove step and a position step to the second axial end, according to Figure 3 of the weld side 34, runs into a radially inner position, wherein at the second axial end the current path 28 is guided in the radially inner position with a groove step but without a position step, following the current path 28 in at least one radially central position with a groove step and a position step to the first axial end into the radially outer position, wherein the current path 28 is opened at each head end 24 of a plug thread 20 by opening the plug thread 20 to form connections 26 of the current path 28.

[0072] Figure 3 shows the welded side 34 of the stator 10 or the stator core 12. A plurality of plug-in windings 20 are arranged in the slot positions 16 or in the slots 30, which are formed by first plug-in windings 20a and second plug-in windings 20b.

[0073] The plug-in turns 20 have at least two different winding patterns on their welded side 34. According to the first winding pattern 36, the first plug-in turns 20a are formed without a layer break, and according to a second winding pattern 38, the second plug-in turns 20b are formed with a layer break.

[0074] In particular, to guide the first plug-in threads 20a past each other, adjacent first plug-in threads 20a are twisted together in opposite directions, as shown in Figure 1. For this purpose, it is provided that the first plug-in threads 20a are formed, for example bent, in opposite circumferential directions in adjacent groove positions 16. Furthermore, it is provided that the first plug-in threads 20a are bulged in the radial direction with a receiving space 40 in order to guide first plug-in threads 20a past adjacent first plug-in threads 20a.Figure 3 shows an arrangement in which the leg of the first plug threads 20a running from the upper weld point 42 on the left into the groove 30 in the view of Figure 3 is radially bulged outwards in the area of ​​the groove 30 and runs radially outside the adjacent first plug threads 20a, and the leg of the first plug threads 20a running from the upper weld point 42 on the right into the groove 30 runs radially inside the adjacent first plug threads 20a.

[0075] Reference symbol list

[0076] 10 Stator

[0077] 12 Stator core

[0078] 14 Rotor mount

[0079] 16 slot positions

[0080] 18 inner circumference

[0081] 20 threaded connections

[0082] 20a first plug thread

[0083] 20b second plug thread

[0084] 22 Stator winding

[0085] 24 Head end

[0086] 26 connection

[0087] 28 Current path

[0088] 30 Nut

[0089] 32 Header

[0090] 34 welding side

[0091] 36 first winding pattern

[0092] 38 second winding pattern

[0093] 40 Recording Room

[0094] 42 welding points

Claims

Patent claims 1. Stator (10) for an electric machine of a traction drive of a motor vehicle, wherein the stator (10) comprises an annular stator core (12) with a plurality of slots (30), wherein a plurality of plug-in turns (20) are provided, which are designed as hairpins and are arranged passing one another in the slots (30) in a hairpin winding technology to form a stator winding (22), wherein the position of the plug-in turns (20) in the slots (30) is defined by the radial position of the plug-in turn (20) and the slot position (16) of the slot (30), and wherein in each slot (30) an odd number of layers of the plug-in turns (20) are arranged one above the other in the radial direction of the stator core (12), wherein the odd number is > 3, wherein the bar winding technology is designed such that the plug-in turns (20) form a current path (28) train,the current path (28) runs continuously from a first axial end of the stator core (12) to a second axial end of the stator core (12) arranged axially opposite the first axial end and back again, such that at the first axial end the current path (28) is guided in a radially outer position with a slot step but without a position step, the current path (28) runs in at least one radially middle position with a slot step and a position step to the second axial end in a radially inner position, wherein at the second axial end the current path (28) is guided in the radially inner position with a slot step but without a position step, the current path (28) runs in at least one radially middle position with a slot step and a position step to the first axial end in the radially outer position, wherein the current path (28) is opened at a head end (24) of a plug-in winding (20) by opening the plug-in winding (20) to form terminals (26) of the current path (28).

2. Stator (10) according to claim 1 , characterized in that the current path (28) forms a completely closed current path (28) with the exception of the terminals (26).

3. Stator (10) according to one of claims 1 or 2, characterized in that all existing position jumps each form a position jump of 1.

4. Stator (10) according to one of claims 1 to 3, characterized in that the current path (28) is guided without points of intersection with respect to the current path (28).

5. Stator (10) according to one of claims 1 to 4, characterized in that the rod winding technology is designed such that the plug-in turns (20) form a plurality of current paths (28) which run continuously from a first axial end of the stator core (12) to a second axial end of the stator core (12) arranged axially opposite the first axial end and back again, such that at the first axial end the current paths (28) are guided in a radially outer position with a slot step but without a position step, the current paths (28) following at least a radially middle position with a slot step and a position step to the second axial end in a radially inner position, wherein at the second axial end the current paths (28) are guided in the radially inner position with a slot step but without a position step,The current paths (28) extend in at least one radially central position with a slot step and a position step to the first axial end in the radially outer position, wherein the current paths (28) are each opened at a head end (24) of a plug-in turn (20) by opening the plug-in turn (20) to form connections (26) of the current paths (28).

6. Stator (10) according to one of claims 1 to 5, characterized in that the stator winding (22) has at least two different winding patterns on the weld side (34), wherein in a first winding pattern (36) first plug-in windings (20a) are provided in a radially inner position or in a radially outer position and wherein according to the first winding pattern (36) the first plug-in windings (20a) are formed without a position jump, and wherein in a second winding pattern (38) second plug-in windings (20b) are provided and according to the second winding pattern (38) the second plug-in windings (20b) are formed with a position jump.

7. Stator (10) according to claim 6, characterized in that the first plug-in windings (20a) in adjacent slot positions (16) are formed in opposite circumferential directions, and that the first plug-in windings (20a) are formed in a radial direction with a receiving space (40) in order to guide first plug-in windings (20a) along adjacent first plug-in windings (20a) in a way that avoids them.

8. Stator (10) according to one of claims 1 to 7, characterized in that the total number of layers of the plug-in windings (20) located in the slot positions (16) is limited to a number of < 13.

9. Use of a rod winding technology for forming a stator winding (22) for a stator (10) of a traction drive of an electrically powered motor vehicle, characterized in that the stator (10) comprises an annular stator core (12) with a plurality of slots (30), wherein a plurality of plug-in turns (20) are provided, which are designed as hairpins and are arranged passing one another in the slots (30) in a hairpin winding technology to form a stator winding (22), wherein the position of the plug-in turns (20) in the slots (30) is defined by the radial position of the plug-in turn (20) and the slot position (16) of the slot (30), and wherein in each slot (30) an odd number of layers of the plug-in turns (20) are arranged one above the other in the radial direction of the stator core (12), wherein the odd number is > 3, wherein the rod winding technology is designed in such a way,that the plug-in windings (20) form a current path (28) which runs continuously from a first axial end of the stator core (12) to a second axial end of the stator core (12) arranged axially opposite the first axial end and back again, such that at the first axial end the current path (28) is guided in a radially outer position with a slot step but without a position step, the current path (28) following at least one radially middle position with a slot step and position step to the second axial end in a radially inner position, wherein at the second axial end the current path (28) is guided in the radially inner position with a slot step but without a position step, the current path (28) following at least one radially middle position with a slot step and position step to the, first axial end runs into the radial outer position, wherein the current path (28) is opened at a head end (24) of a plug-in turn (20) by opening the plug-in turn (20) to form terminals (26) of the current path (28).

10. Traction drive for an electrically powered motor vehicle, comprising an arrangement of a rotor and a stator (10), characterized in that the stator (10) is designed according to one of claims 1 to 8.

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