CN110474451B

CN110474451B - Stator for an electric machine, electric machine and method for producing a stator for an electric machine

Info

Publication number: CN110474451B
Application number: CN201910353967.0A
Authority: CN
Inventors: A.沙格哈吉
Original assignee: Volkswagen AG
Current assignee: Volkswagen AG
Priority date: 2018-05-09
Filing date: 2019-04-29
Publication date: 2021-08-10
Anticipated expiration: 2039-04-29
Also published as: DE102018207231A1; CN110474451A

Abstract

A stator for an electric machine includes a plurality of stator slots, the stator including a first stator winding including a first set, a second set, a third set, and a fourth set of hairpin conductors. The hairpin conductors each have a free first end region and a free second end region. The end regions of the hairpin conductors are connected to each other except for the winding start and the winding end, such that the first end region of each first set of hairpin conductors is connected to the first end region of a second set of hairpin conductors, the second end region of each second set of hairpin conductors is connected to the first end region of a third set of hairpin conductors, the second end region of each third set of hairpin conductors is connected to the first end region of a fourth set of hairpin conductors, and the second end region of each fourth set of hairpin conductors is connected to the second end region of the first set of hairpin conductors, thereby consecutively constituting a first stator winding by the first, second, third and fourth sets of hairpin conductors.

Description

Stator for an electric machine, electric machine and method for producing a stator for an electric machine

Technical Field

The invention relates to a stator for an electric machine, an electric machine and a method for manufacturing a stator for an electric machine.

Background

In the production of the electric machine, it should be noted that the voltage difference between adjacent conductors in the stator slots should be as small as possible, since otherwise partial discharges between the insulating materials of the conductors or between the conductors would occur in view of the voltage loading during operation. This type of partial discharge may damage or even destroy the insulation system of the electrical machine during its service life. To reduce the voltage difference, it is known in the prior art to arrange a plurality of insulating materials in the stator slots. Furthermore, special wire insulation or operation of the electric machine at lower voltages can be selected. The increase of the insulating material in the stator slots has the disadvantage that the copper filling in the stator slots is thereby reduced. Furthermore, the insulation system is also expensive and complicated. This in turn increases the losses in the electric machine. When the motor is operating at a lower voltage, not all of the desired power levels are available for use.

It is also desirable for the electric machine to be able to meet specific requirements with regard to torque and power, if the machine is to be constructed with the highest possible number of turns for a predetermined overall length. In other words, it is preferable to save installation space, in particular the axial length, under the given conditions.

Disclosure of Invention

The object of the invention is to improve a stator for an electrical machine in such a way that the potential distribution between adjacent conductors in the stator slots is reduced. Furthermore, a stator should be provided, the number of turns of which is flexible. The installation space of the stator should also be optimized.

The above object is solved by a stator for an electrical machine, said stator comprising a plurality of stator slots. The stator further includes a first stator winding including first, second, third, and fourth sets of hairpin conductors. The hairpin conductors of the first and third sets extend through a first number of stator slots, while the hairpin conductors of the second and fourth sets extend through a second number of stator slots. The first number is different from the second number, so that the hairpin conductors of the first and third sets extend through a different number of stator slots than the hairpin conductors of the second and fourth sets.

The hairpin conductors each have a free first end region and a free second end region, wherein the end regions of the hairpin conductors are connected to one another except for the winding start and the winding end, such that the first end region of each hairpin conductor of the first group is connected to the first end region of a hairpin conductor of the second group, wherein the second end region of each hairpin conductor of the second group is connected to the first end region of a hairpin conductor of the third group, wherein the second end region of each hairpin conductor of the third group is connected to the first end region of the hairpin conductor of the fourth group, and wherein the second end region of each hairpin conductor of the fourth group is connected to the second end region of the hairpin conductor of the first group, so that the first stator winding is consecutively formed by the hairpin conductors of the first, second, third and fourth groups.

The consecutive first stator windings extend from the winding start to the winding end. This means that one end region of one hairpin conductor becomes the winding start and one end region of the other hairpin conductor becomes the winding end, and thus the winding start and the winding end are not connected to the other end regions of the other hairpin conductor.

In other words, the first end region of the first hairpin conductor of the first group is connected to the first end region of the first hairpin conductor of the second group, wherein the second end region of the first hairpin conductor of the second group is connected to the first end region of the first hairpin conductor of the third group, wherein the second end region of the first hairpin conductor of the third group is connected to the first end region of the first hairpin conductor of the fourth group, wherein the second end region of the first hairpin conductor of the fourth group is connected to the second end region of the second hairpin conductor of the first group, wherein the first end region of the second hairpin conductor of the first group is connected to the first end region of the second hairpin conductor of the second group, etc. The described winding continues on all hairpin conductors to form a coherent stator winding. The second end regions of the first hairpin conductors of the first group here form the winding start and the second end regions of the last hairpin conductors of the fourth group form the winding end.

The electric machine is especially a rotating field machine, mainly a permanent magnet excited synchronous machine. Preferably, the electric machine is understood to be an electric drive, a lighting generator (Lichtmaschine) or a generator. In particular to electric drives for vehicles, in particular motor vehicles. However, it can also be applied to other electrical devices, for example electrical drives for household appliances or industrial machines.

The stator slots extend in the circumferential direction. The stator comprises in particular a stator core group on the radially inner side of which slots in the form of radial slots are configured. The slots are stator slots, which may be configured with slot insulation.

The term "hairpin conductor" is to be understood in particular as a pin, in particular a U-shaped pin.

The expression "hairpin conductor extends through a first or a second number of stator slots" means that the corresponding set of hairpin conductors spans the first or the second number of stator slots. The hairpin conductor has in particular a first arm, a second arm and a curved connecting section, respectively. The connecting section connects the two arms and is arranged on the end of the hairpin conductor opposite the free end region of the arms. If the hairpin conductor extends through a first number of stator slots, this means that the bent connecting section spans the first number of stator slots.

The first and/or second and/or third and/or fourth group may in particular be divided into groups, wherein a group is characterized in that the first arms of the hairpin conductors are all arranged in the same stator slot, wherein the second arms of the hairpin conductors are likewise arranged in another, but all arranged in one and the same stator slot. Accordingly, a grouping of hairpin conductors is characterized by a curved connecting segment spanning these same stator slots. The partial groups of a group are preferably arranged at uniform distances from one another in the circumferential direction.

The hairpin conductors of the same group are characterized by extremely similar geometry and dimensions. The hairpin conductors of the same group may vary slightly in view of the arrangement of the hairpin conductors inside the slot, i.e., the slot position.

In particular, the hairpin conductors of the first group are connected to the hairpin conductors of the first group of the second group, which are in turn connected to the hairpin conductors of the first group of the third group, which are in turn connected to the hairpin conductors of the first group of the fourth group. The last mentioned hairpin conductor is in turn connected to the first group of hairpin conductors, in particular to the second group of hairpin conductors. Whereby the winding scheme continues on groups of different levels.

The first number of stator slots is different from the second number, in particular by two stator slots. Here, the first number and/or the second number are even numbers and/or odd numbers. The first number and/or the second number are in particular six or eight stator slots.

The stator comprises in particular not only the first stator winding but also a second and a third stator winding which are of similar design to the first stator winding. Whereby the stator comprises one stator winding per motor phase. The first stator winding forms, in particular together with the other two stator windings, a winding head of the stator.

Through the above-described connection of the different sets of hairpin conductors, the hairpin conductors spanning different numbers of stator slots are respectively connected to each other. In other words, hairpin conductors having different hairpin widths are alternately combined. By the construction of the first stator winding, the voltage between the hairpin conductors inside the same stator slot is reduced. This causes the potential difference in percentage units inside the stator slots to decrease from 35% to only 20%, while the potential distribution in percentage units in the winding heads also decreases to about 20%.

Each set of hairpin conductors comprises in particular the same number of hairpin conductors. Furthermore, the hairpin conductors of each group comprise, in particular, the same number of hairpin conductors. Here, the number of hairpin conductors of each group and/or each subgroup may be odd. This brings great advantages in the case of a flexible construction of the stator. In addition to the disadvantageous potential distribution in the prior art, the hairpin-type pin technique known from the prior art is also limited in that an even number of conductors are required in the stator slots. This does not allow a flexible design of the stator.

Advantageously, the hairpin conductors of at least one group of the first and/or second and/or third and/or fourth group are axially stacked. The respective stacked hairpin conductors can constitute part of the coil of the stator.

Furthermore, the hairpin conductors of at least one group of the first and/or second and/or third and/or fourth group are stacked radially.

The different sets of two grouped hairpin conductors can be stacked in particular radially, so that one grouped hairpin conductor alternates radially with the other grouped hairpin conductor. Thus, each hairpin conductor of one grouping is surrounded and transposed by two hairpin conductors of the other grouping, except for the radially outermost and inner hairpin conductors.

The first group may constitute a first partial coil in a first axial position, and the second group may constitute a second partial coil in the first position. The third set may constitute the first partial coil in the second axial position and the fourth set may constitute the second partial coil in that position. Furthermore, all groups may constitute four partial coils in the first axial position.

Preferably, the connecting section of the hairpin conductors of the first and second groups is composed of three partial sections, wherein the first partial section and the third partial section extend in the radial direction, wherein the first partial section is connected to the first arm of the respective hairpin conductor, and wherein the second partial section arranged between the first partial section and the third partial section extends in the circumferential direction. The respective hairpin conductor is designed accordingly and is arranged in the stator slot such that the arms of the hairpin conductor extend in a radial direction, wherein a first partial section extending in the radial direction is connected to the first arm, a second partial section extending in the circumferential direction is connected to the first partial section, and a third partial section is connected to the second partial section, extends in the opposite radial direction with respect to the first partial section, and merges into the second arm.

By means of this special shaping of the hairpin conductor, the installation space can be optimized in particular, since the hairpin conductor can be placed in the stator slot in a particularly space-saving manner. The radial orientation of the first and third partial sections enables the hairpin conductor to be arranged such that it lies against the stator core assembly. At least for the first hairpin conductor, or the hairpin conductor layer, in the axial direction, this applies to the case where the hairpin conductors are stacked in the axial direction.

The grouped hairpin conductors can be divided into a first subgroup and a second subgroup, respectively, wherein the first partial sections of the first subgroup extend in opposite radial directions compared to the first partial sections of the second subgroup. The subgroups constitute smaller units of the group. This means that the hairpin conductors of the same group, the first arms of which are arranged in the same stator slot, extend in different radial directions along the first partial section of the bent connecting section. If the packet comprises a plurality of hairpin conductors, it is preferred that half of these hairpin conductors are in a first subgroup and the other half of these hairpin conductors are in a second subgroup. In view of the different configurations of the hairpin conductors of the first and second subgroups, the hairpin conductors of the first subgroup are thereby stacked in the axial direction, while the hairpin conductors of the second subgroup are likewise stacked one behind the other in the axial direction. Since all the hairpin conductors grouped are thus stacked in succession, an axial installation space is saved significantly.

Furthermore, the curved connecting section of the hairpin conductors of the first and/or second and/or third and/or fourth group is formed by three partial sections, wherein the first partial section is connected to the first arm and the third partial section is connected to the second arm. The first partial section extends in particular in a direction having a radial component and an axial component, while the second partial section extends in the circumferential direction and the third section extends in the opposite direction with respect to the first partial section. By means of the radial component of the extensions of the first and third partial section, spaces can be provided, with which different groups of hairpin conductors can be stacked alternately in the radial direction. The axial component of the extension of the first partial section and the third partial section provides structural space in the axial direction in order to span other groups of hairpin conductors.

The dimensions of the first and third partial section are precisely selected such that as much as possible of the installation space can be saved in the axial and radial directions.

In a further aspect, the invention relates to an electrical machine, in particular a rotating field electrical machine, comprising at least one stator as described above. The method comprises the following steps: the first group of hairpin conductors is arranged, the second group of hairpin conductors is arranged, the third group of hairpin conductors is arranged, and the fourth group of hairpin conductors is arranged, wherein the hairpin conductors respectively have a free first end region and a free second end region. Furthermore, the method comprises overlapping and contacting of the end regions of the hairpin conductors such that the first end region of each first set of hairpin conductors is connected to the first end region of the second set of hairpin conductors, wherein the second end region of each second set of hairpin conductors is connected to the first end region of the third set of hairpin conductors, wherein the second end region of each third set of hairpin conductors is connected to the first end region of the fourth set of hairpin conductors, and wherein the second end region of each fourth set of hairpin conductors is connected to the second end region of the first set of hairpin conductors, thereby consecutively forming the stator winding by the first, second, third and fourth sets of hairpin conductors.

Further, corresponding slot insulation may be placed in the stator slots of the stator core pack prior to placing the hairpin conductors.

In particular the first and/or second and/or third and/or fourth set of hairpin conductors may comprise an odd number of hairpin conductors. In this case, the method may comprise overlapping in particular the respective sets of hairpin conductors around a certain slot position before the end regions of the hairpin conductors are brought into contact. The groove position is here a position radially inside the same groove. This step is also called coining. The hairpin conductors are in particular radially outermost or radially innermost hairpin conductors of the respective set. The hairpin conductors are first bent in a radial direction after leaving the stator core group, and specifically are bent more sharply than the other hairpin conductors of the corresponding group, so as to provide space. In this way, too small a distance between the hairpin conductors, which would release voltage during operation, is avoided. In the case of an odd number of hairpin conductors in the same stator slot, a collision between a hairpin conductor bent in a clockwise direction and a hairpin conductor bent in a counter-clockwise direction may occur, compared to an even number of hairpin conductors in a stator slot (in the case of an even number of hairpin conductors, the respective hairpin conductors are connected in pairs with other sets of hairpin conductors), which collision is avoided by this method step.

The connection of the respective end regions is accomplished in particular by welding.

Drawings

In the drawings, schematically:

FIG. 1 shows a diagram of the steps of a method according to the invention;

figure 2 shows a perspective view of a component of a stator according to the invention; and

fig. 3 shows a combined state of the stator according to fig. 2 according to the invention;

fig. 4 shows a winding scheme of a first stator winding of the stator according to the invention of fig. 2 and 3;

fig. 5 shows a perspective view of the B-side of a stator according to the present invention;

fig. 6 shows a perspective view of a further hairpin conductor of a stator according to the invention;

fig. 7 shows a perspective view of the respective groups of the third and fourth groups of hairpin conductors of the stator according to the invention according to fig. 6; and

fig. 8 shows a perspective view of the step assembly of the stator according to the present invention of fig. 7 and 8.

Detailed Description

Fig. 1 shows a method (100) according to the invention. The method comprises the following steps: -arranging (102) a first set (21) of hairpin conductors (16), -arranging (103) a second set (22) of hairpin conductors (16), -arranging (104) a third set (23) of hairpin conductors (16) and-arranging (105) a fourth set (24) of hairpin conductors (16) in the stator core pack (11) or in the respective stator slots (12) of the stator core pack (11).

The first (21) and third (23) groups of hairpin conductors (16) extend in a different number of stator slots (12) than the second (22) and fourth (24) groups of hairpin conductors (16).

Furthermore, the method comprises overlapping and contacting (107) end regions (20) of the hairpin conductors (16), in particular the first end regions of each first set (21) of hairpin conductors (16) being connected to the first end regions of a second set (22) of hairpin conductors (16), wherein the second end region of each second set (22) of hairpin conductors (16) is connected to the first end region of a third set (23) of hairpin conductors (16), wherein the second end region of each third set (23) of hairpin conductors (16) is connected to the first end region of a fourth set (24) of hairpin conductors (16), and wherein the second end region of each fourth set (24) of hairpin conductors (16) is connected to the second end region of the first set (21) of hairpin conductors (16) so as to consecutively form a stator winding (28 a).

Optionally, the method comprises, prior to placing the hairpin conductor (16), placing (101) a slot insulation (13) in the stator slot (12). Furthermore, when the set of hairpin conductors (16) includes an odd number of hairpin conductors (16), the method may further include an overlap (106) of the set of hairpin conductors (16) around a certain slot location (25). Preferably, this involves the radially outermost or radially innermost hairpin conductor (16) of the group.

Fig. 2 shows a perspective view of a component of the stator (10) according to the invention. The first (21) and second (22) groups of hairpin conductors (16) of the first stator winding (28a) are shown in one third of the left-hand drawing. The hairpin conductor (16) has a first arm (17), a second arm (18) and a curved connecting section (19), wherein the curved connecting section (19) can be divided into a first partial section (19a), a second partial section (19b) and a third partial section (19 c). The first partial section (19a) and the third partial section (19c) extend in a radial direction (31) after being arranged in the stator slot (12), wherein the first partial section (19a) extends in the opposite radial direction (31) compared to the third partial section (19 c). A second partial section (19b) extending between the first partial section and the third partial section extends in the axial direction (32) of the stator (10).

The middle third of fig. 2 shows the slot insulation (13) which is arranged in the stator slots (12) of the stator core pack (11) which is shown in the right side drawing plane third. After the slot insulation (13) is placed, a hairpin conductor (16) is placed.

Fig. 3 shows the stator (10) according to fig. 2 in a combined state according to the invention. Slot insulation (13) is disposed in corresponding stator slots (12) of the stator core pack (11). Furthermore, a hairpin conductor (16) has been arranged, and in particular the hairpin conductor is arranged from the a side (14), while the respective arms of the hairpin conductor (16) are overlapped on the B side (15), and the end regions (20) of the arms are in contact with each other.

In general, three stator windings, a first stator winding (28a), a second stator winding (28b), and a third stator winding (28c), are shown in fig. 3. Each stator winding comprises four groups, namely a first group (21), a second group (22), a third group (23) and a fourth group (24) of hairpin conductors (16). The grouping of the first stator windings (28a) is exemplarily shown. The first group (21) then comprises a first group (21a), a second group (21b) and a third group (21c), the second group (22) then comprises a first group (22a), a second group (22b) and a third group (22c), the third group (23) comprises a first group (23a), a second group (23b) and a third group (23c), and the fourth group (24) comprises a first group (24a), a second group (24b) and a third group (24 c).

The grouped hairpin conductors (16) are stacked on top of each other in an axial direction (30). The bent connecting sections (19) of the hairpin conductors (16) of the second group (22) span the respective hairpin conductors (16) of the first group (21) in the circumferential direction (32). In particular, the bent connecting sections (19) of the sub-groups of the second group (22) span the hairpin conductors (16) of the corresponding sub-groups of the first group (21). The same applies to the hairpin conductors (16) of the third and fourth groups (23, 24), wherein the fourth group (24) of hairpin conductors (16) spans the third group (23) of hairpin conductors.

Fig. 4 shows a winding scheme of the first stator winding (28a) of the stator (10) according to the invention. The different stator slots (12) are designated here by the corresponding values 1 to 72 in the horizontal direction. For this purpose, different groove positions (25) are shown in the vertical direction. The groove position (25) is defined as the position radially (31) within the same groove.

The horizontal, non-dashed sections between

slot positions

6 and 11 shown in the winding scheme indicate how many stator slots are spanned by the bent connecting segments of the hairpin conductors (16) of the first group (21) of first groups (21a), while the corresponding horizontal, non-dashed sections between

slots

5 and 12 indicate how many stator slots are spanned by the hairpin conductors of the first group (22a) of the second group (22). The same applies to the other illustrated packets. It is clear from fig. 4 how the hairpin conductors (16) of the first group (21a) of the first set (21) are connected to the hairpin conductors (16) of the first group (22a) of the second set (22), which in turn are connected to the hairpin conductors (16) of the first group (23a) of the third set (23), which in turn are connected to the hairpin conductors (16) of the first group (24a) of the fourth set. The last hairpin conductor (16) is in turn connected to the hairpin conductors (16) of the first group (21), in particular to the hairpin conductors of the second group (21 b). Whereby the winding scheme continues on groups of different levels.

Fig. 5 shows a perspective view of the B-side of the stator (10) according to the invention. The figure shows how the radially innermost hairpin conductors overlap radially around a certain slot position when the number of hairpin conductors (16) of a grouping is odd, i.e. when the number of hairpin conductors (16) in a stator slot (12) is odd. The respective hairpin conductor (16) has a first arm (17) and a second arm (18) which are bent radially inward around a slot position in a radial direction (31) for providing space after the respective arm leaves the stator slot (12). Thereby providing space to avoid collisions between end regions that are curved in the clockwise direction and in the counter-clockwise direction in the circumferential direction (32).

Fig. 6 shows a perspective view of the hairpin conductors (16) of a further first group (21), more precisely a first group (21a), and a second group (22), more precisely a second group (22a), of the stator (10) according to the invention.

The hairpin conductors (16) of the first (21) and second (22) groups are substantially shaped similarly, however spanning a different number of stator slots (12). In addition to the first arm (17) and the second arm (18), a curved connecting section (19) is provided, which has a first partial section (19a) extending radially and a third partial section (19c) extending radially and a second partial section (19b) extending in the circumferential direction. Furthermore, the hairpin conductors (16) of the first group (21) of first sub-groups (21a) and the first sub-groups (22a) of the second group (22) can each be divided into two sub-groups (21aa, 21bb, 22aa, 22 bb). The different subgroups extend in opposite radial directions, so that the corresponding hairpin conductors (16) of the subgroups at different radial positions are stacked, thus saving axial installation space.

Fig. 7 shows a perspective view of the hairpin conductors of the third group (23) and of the fourth group (24) of the stator (10) according to fig. 6, wherein the two hairpin conductors of the illustrated groups are stacked alternately in the radial direction.

Fig. 8 shows a perspective view of the stepped assembly of the stator (10) according to the invention from fig. 7 and 8. After the slot insulation (13) is arranged in the stator slots (12) of the stator core group (11), a first set (21) of hairpin conductors (16) is arranged for each of the three stator windings. In particular, three groups of the first group (21) are provided for each stator winding. In a subsequent step, the corresponding packets of the second group (22) are relocated. Subsequently, the grouped hairpin conductors (16) of the third group (23) are re-conducted and the grouped hairpin conductors (16) of the fourth group (24) are re-conducted. In the last step, the connecting segments are overlapped and contacted. The contacting and thus winding scheme corresponds to fig. 4. The grouped hairpin conductors (16) of the third and fourth groups (23, 24) are arranged in the stator slots (12) such that the grouped hairpin conductors of the third and fourth groups partly span the two adjacent grouped hairpin conductors (16) of the first and second groups (21, 22).

List of reference numerals

10 stator

11 stator core group

12 stator slots

13 groove insulation part

Side 14A

Side 15B

16 hairpin conductor

17 first arm

18 second arm

19 curved connecting section

19a first partial section

19b second partial section

19c third partial section

20 end segment

21 first group

21a first packet

21aa first subgroup

21bb second subgroup

21b second packet

21c third grouping

22 second group

22a first packet

22aa first subgroup

22bb second subgroup

22b second packet

22c third sub-group

23 third group

23a first packet

23b second packet

23c third sub-group

24 fourth group

24a first packet

24b second packet

24c third grouping

25 groove position

26 winding start

27 winding terminal

28a first stator winding

28b second stator winding

28c third stator winding

30 axial direction

31 radial direction

32 circumferential direction

100 method

101 a slot insulation part

102 placing a first group

103 arranging a second group

104 arranging a third group

105 arranging a fourth group

106 overlap of hairpin conductors around a slot location

107 overlap and contact of the end sections.

Claims

1. A stator (10) for an electrical machine comprising a plurality of stator slots (12),

wherein the stator (10) comprises a first stator winding (28a),

wherein the first stator winding (28a) comprises a first group (21), a second group (22), a third group (23) and a fourth group (24) of hairpin conductors (16),

wherein the hairpin conductors (16) of the first and third sets (21, 23) extend through a first number of stator slots (12),

wherein the hairpin conductors (16) of the second and fourth sets (22, 24) extend through a second number of stator slots (12),

wherein the first number is different from the second number,

wherein the hairpin conductors (16) each have a free first end region and a free second end region,

characterized in that the end regions of the hairpin conductors (16) are connected to one another, apart from the winding start (26) and the winding end (27), in such a way that the first end region of each hairpin conductor (16) of the first group (21) is connected to the first end region of the hairpin conductors (16) of the second group (22), in that the second end region of each hairpin conductor (16) of the second group (22) is connected to the first end region of the hairpin conductors (16) of the third group (23), in that the second end region of each hairpin conductor (16) of the third group (23) is connected to the first end region of the hairpin conductor (16) of the fourth group (24), and in that the second end region of the hairpin conductor (16) of each fourth group (24) is connected to the second end region of the hairpin conductor (16) of the first group (21), whereby the first stator winding (28a) is consecutively formed by a first (21), a second (22), a third (23) and a fourth (24) set of hairpin conductors (16),

and wherein the hairpin conductor (16) comprises a first arm (17), a second arm (18) and a curved connecting section (19), respectively,

wherein the first group (21) and/or the second group (22) and/or the third group (23) and/or the fourth group (24) has at least two groups,

wherein the hairpin conductors (16) of the same group are configured such that the first arms (17) of the hairpin conductors (16) are arranged in the same stator slot (12), and wherein the second arms (18) of the hairpin conductors (16) are arranged in the same stator slot (12).

2. The stator (10) of claim 1 wherein at least one grouping of hairpin conductors (16) is stacked in an axial direction (30).

3. The stator (10) according to claim 1, wherein at least one grouping of hairpin conductors (16) is stacked in a radial direction (31).

4. A stator (10) according to claim 3, characterized in that the different groups of two groups of hairpin conductors (16) are stacked in a radial direction (31) so that one group of hairpin conductors (16) and the other group of hairpin conductors (16) alternate in the radial direction (31).

5. Stator (10) according to one of the claims 1 to 4, characterized in that the curved connecting section (19) of the hairpin conductors (16) of the first group (21) and/or the second group (22) and/or the third group (23) and/or the fourth group (24) consists of three partial sections, wherein the first partial section (19a) and the third partial section (19c) extend in a radial direction (31), wherein the first partial section (19a) is connected to the first arm (17), and wherein the second partial section (19b) arranged between the first partial section and the third partial section extends in a circumferential direction (32).

6. A stator (10) according to claim 5, characterized in that a group constitutes a first subgroup and a second subgroup, respectively, wherein the first partial sections (19a) of the hairpin conductors (16) of the first subgroup extend in opposite radial directions compared to the first partial sections (19a) of the hairpin conductors (16) of the second subgroup.

7. An electric machine, characterized in that the electric machine has a stator (10) according to any one of claims 1-6.

8. The electric machine of claim 7, wherein the electric machine is a rotating field electric machine.

9. A method (100) of manufacturing a stator (10) according to any of the claims 1 to 6, characterized in that the method (100) comprises the steps of:

-arranging a first set (21) of hairpin conductors (16);

-arranging a second set (22) of hairpin conductors (16);

-arranging a third set (23) of hairpin conductors (16);

-arranging a fourth set (24) of hairpin conductors (16);

wherein the hairpin conductors (16) of the first (21), second (22), third (23) and fourth (24) groups have a free first end region and a free second end region, respectively;

-overlapping and contacting end regions of hairpin conductors (16) such that a first end region of each first set (21) of hairpin conductors (16) is connected to a first end region of a second set (22) of hairpin conductors (16), wherein a second end region of each second set (22) of hairpin conductors (16) is connected to a first end region of a third set (23) of hairpin conductors (16), wherein a second end region of each third set (23) of hairpin conductors (16) is connected to a first end region of a fourth set (24) of hairpin conductors (16), and wherein a second end region of each fourth set (24) of hairpin conductors (16) is connected to a second end region of a first set (21) of hairpin conductors (16), thereby passing through the first set (21), the second set (22) and the first end region of the second set (21), The hairpin conductors (16) of the third and fourth groups (23, 24) form a first stator winding (28a) consecutively.

10. Method (100) according to claim 9, wherein the first (21) and/or second (22) and/or third (23) and/or fourth (24) groups comprise an odd number of hairpin conductors (16), characterized in that the method (100) comprises overlapping respective groups of hairpin conductors (16) around a slot location (25) before the hairpin conductors (16) are contacted.