Stator of an electric machine

Abstract

The invention relates to a stator of an electric machine (2), the stator comprising a stator core (4) which has stator teeth (5) and a stator yoke (7) connecting the stator teeth (5), wherein stator slots (6) are formed between the stator teeth (5), each stator slot having a slot base (8) facing the stator yoke (7), wherein the stator core (4) comprises a plurality of sheet-metal laminations (10) which lie one above the other in the axial direction with respect to a stator axis (3), wherein slot apertures (11) are provided in the sheet-metal laminations (10) for forming the stator slots (6), wherein yoke slots (12) are formed in a plurality of sheet-metal laminations (10) at the slot bottom (9) of the slot apertures (11), each yoke slot extending from the slot bottom (9) in a radial direction facing away from the slot aperture (11), characterised in that yoke slots (12) in at least one of the sheet-metal laminations (10), in particular in each sheet-metal lamination (10), are each offset relative to one another in the circumferential direction with respect to yoke slots (12) of at least one adjacent sheet-metal lamination (10) so as to prevent overlapping of yoke slots (12) in adjacent sheet-metal laminations (10).

Description

[0001] R. 415019-1

[0002] - 1 -

[0003] Description

[0004] title

[0005] Stator of an electric machine

[0006] State of the art

[0007] The invention relates to a stator of an electrical machine according to the preamble of the main claim.

[0008] A stator of an electric machine is already known from JP2013093932 A2, comprising a stator core with stator teeth and a stator yoke connecting the stator teeth. Stator slots are formed between the stator teeth, each with a slot base facing the stator yoke. The stator core has a plurality of sheet metal layers arranged axially with respect to a stator axis, with slot slots provided in the sheet metal layers to form the stator slots. In several sheet metal layers, yoke slots are formed in the slot base of the slot slots, each extending radially away from the slot base.The yoke slots in the stator yoke can generate significant additional magnetic resistance because they form multiple axially oriented slots that magnetic flux can only overcome via an air gap created by the slots. This increased magnetic resistance impairs magnetic flux conduction in the stator core, thus reducing the maximum torque and power output of the electric machine.

[0009] Advantages of the invention

[0010] In contrast, the stator of an electric machine according to the invention, with the characterizing features of the main claim, has the advantage that the magnetic resistance of the stator yoke is reduced and the magnetic flux conduction in the stator core is improved. This increases the maximum torque and maximum power of the electric machine. According to the invention, this is achieved by providing yoke slots in at least one of the lamination layers, in particular in each lamination layer, R. 415019-1

[0011] - 2 - each yoke slot is offset from the other in the circumferential direction to prevent overlapping of yoke slots in adjacent sheet layers. By preventing overlapping yoke slots, the magnetic flux, when it encounters a yoke slot, can divert to an adjacent sheet layer and thus bypass the respective yoke slot.

[0012] The yoke slots are designed to facilitate the bending of the sheet metal layers around the stator axis.

[0013] The measures listed in the dependent claims enable advantageous further developments and improvements of the stator of an electrical machine specified in the main claim.

[0014] According to an advantageous first embodiment, in the same stator groove, along an axial extension of the stator groove, in particular along a section of the stator groove or along the full length of the stator groove, a yoke slot in a first slot base position and a yoke slot in a second slot base position can be provided alternately from sheet layer to sheet layer or from sheet layer stack to sheet layer stack, wherein the two slot base positions are offset circumferentially. In other words, several sequences of a yoke slot in a first slot base position and a yoke slot in a second slot base position are provided one after the other in the same stator groove along the superimposed sheet layers. In this way, the stator core according to the invention can be manufactured particularly easily.

[0015] According to an advantageous second embodiment, a slotted and a slotless slot base can be provided alternately in the same stator groove along the axial extent of the stator groove, from one sheet layer to the next. In other words, several sequences of a slotted slot base and a slotless slot base are provided one after the other in the same stator groove along the superimposed sheet layers. The stator core according to the invention can also be manufactured particularly easily in this way.

[0016] It is particularly advantageous if the stator core is formed from at least one spirally wound strip of sheet metal wound vertically around the stator axis, wherein the sheet metal layers of the stator core are the first sheet metal layers and between the first R. 415019-1

[0017] - 3 -

[0018] The sheet metal layers comprise two layers of sheet metal lying on the same side, with each second sheet metal layer having at least one adjacent first sheet metal layer. In this way, a vertically wound stator core with low magnetic resistance is achieved.

[0019] According to an advantageous first manufacturing variant for producing the two exemplary embodiments, the first lamination layers of the stator core can be formed by a spirally wound first lamination strip, and the second lamination layers of the stator core by a spirally wound second lamination strip. Both lamination strips can each be produced using a simple stamping device. The stator core comprises two spirals of lamination strips.

[0020] According to the first embodiment and the first manufacturing variant, the first sheet metal strip can only have yoke slots in a first slot base position, and the second sheet metal strip can only have yoke slots in a second slot base position, with the two slot base positions being offset from each other circumferentially. In this way, the first sheet metal strip can be produced in a simple first punching unit, and the second sheet metal strip in a simple second punching unit. The punching of the yoke slots and / or the channel slots can be carried out in the first and second punching units independently of the sheet metal layer and / or without changing or altering the die.

[0021] According to the second embodiment and the first manufacturing variant, both sheet metal strips can have at least one yoke slot, in particular two yoke slots in different slot base positions, at every second slot, and a slotless slot base at the remaining slots, wherein the two sheet metal strips are offset from each other by one slot pitch. In this way, the first sheet metal strip can be produced in a simple first punching unit and the second sheet metal strip in a simple second punching unit. The punching of the yoke slots and / or the channel slots can be carried out in the first and second punching units independently of the sheet metal layer and / or without changing or altering the die.

[0022] According to an advantageous second manufacturing variant for producing the two embodiments, the first and second sheet metal layers of the stator core can be formed by a single spirally wound sheet metal strip. R. 415019-1

[0023] - 4 -

[0024] According to the first embodiment and the second manufacturing variant, the single spirally wound sheet metal strip can have a yoke slot in each groove slot, wherein the sheet metal strip has only yoke slots in a first slot base position in the first sheet layers and only yoke slots in a second slot base position in the second sheet layers, the two slot base positions being offset from each other circumferentially. In this way, only a single punching device is required. However, the punching of the yoke slots and / or the channel slots in the punching device must be sheet layer-dependent and / or involve changing or switching the punching die and / or a change in the relative punching position.

[0025] According to the second embodiment and the second manufacturing variant, the single spirally wound sheet metal strip can have at least one yoke slot, in particular two yoke slots at different slot base positions, at the slot base of every second slot slot, and a slotless slot base at the remaining slots, wherein the stator has an odd number of stator teeth.

[0026] Furthermore, the yoke slots in the respective sheet metal strip can extend circumferentially along a radial dimension away from the base of the slot, particularly with a curved profile. This reduces magnetic flux losses in the stator core. Additionally, the air gap in the yoke slots can be reduced because the flanks of the yoke slots fit together more closely when bent around the stator axis.

[0027] According to an advantageous third embodiment, the yoke slots in the first slot base position and the yoke slots in the second slot base position can be arranged in the same stator slot, extending radially outwards from the slot base in opposite circumferential directions. This reduces magnetic flux losses in the stator core because the flux lines pass through the yoke slots at an angle with a smaller air gap.

[0028] According to an advantageous fourth embodiment, it can be provided that in the same stator groove the yoke slots in the first slot base position and the yoke slots in the second slot base position are arranged along their radial extent R. 415019-1

[0029] - 5 - run radially outwards from the base of the slot in a circumferential direction facing each other. In this way, the magnetic flux losses in the stator core can be reduced if this increases the proportion of flux lines that do not pass through the yoke slots.

[0030] It is advantageous if, according to a first and second cooling channel variant, a circumferentially extending channel slot is formed at several or all yoke slots, particularly at the ends of the yoke slots facing away from the groove slots, to form at least one cooling channel extending axially in the stator yoke. This cooling channel is formed, in particular, between two adjacent stator grooves or between two adjacent stator teeth in the stator yoke. In this way, the cooling of the stator core can be improved. The cooling channel in the stator yoke between two adjacent stator grooves, i.e., in the region of a hypothetical radial extension of a stator tooth, generates a particularly low magnetic resistance in the stator yoke.

[0031] It is also advantageous that, to form the respective cooling channel, channel slots in adjacent sheet metal layers overlap.

[0032] According to an advantageous third cooling channel variant, several separate channel slots can be formed in the respective sheet metal strip to create at least one cooling channel extending axially in the stator yoke. This cooling channel is arranged circumferentially, in particular between the two slot base positions of one of the stator slots, and / or radially, in particular between a slot base and an end of the yoke slots facing away from the slot base. In this way, the channel slots are decoupled from the yoke slots, allowing the cooling channels in the stator yoke to be arranged optimally with regard to cooling or with regard to low magnetic flux losses.

[0033] It is further advantageous if adjacent lamination layers of the stator core are firmly connected to one another, in particular by interlocks, bonding, or welding. In this way, a mechanically stable laminated core is formed.

[0034] The invention further relates to an electric machine with a stator according to the invention. R. 415019-1

[0035] - 6 -

[0036] drawing

[0037] Exemplary embodiments of the invention are shown in simplified form in the drawing and explained in more detail in the following description.

[0038] They show:

[0039] Fig. 1 shows a partial view of a stator core according to a first embodiment of the invention.

[0040] Fig. 2 shows a section through the stator core along line 11-11 in Fig. 1 with a slotted groove base according to the invention in a stator groove,

[0041] Fig. 3A shows a first sheet layer according to the invention in a first embodiment,

[0042] Fig. 3B shows a second sheet layer according to the invention based on the first embodiment,

[0043] Fig. 4 shows the stator core according to Fig. 2 in a top view for a first cooling channel variant,

[0044] Fig. 5 shows the stator core according to Fig. 2 in a top view for a second cooling channel variant,

[0045] Fig. 6 shows a section through a stator core according to the invention with a slotted groove base in a stator groove according to a second embodiment.

[0046] Fig. 7A shows a first sheet layer according to the invention in a second embodiment,

[0047] Fig. 7B shows a second sheet layer according to the invention in the second embodiment,

[0048] Fig. 8A shows a first manufacturing variant for producing one of the two embodiments of the stator core according to the invention.

[0049] Fig. 8B shows a second manufacturing variant for producing one of the two embodiments of the stator core according to the invention.

[0050] Fig. 9 shows a sheet metal layer according to a third embodiment with a third cooling channel variant and

[0051] Fig. 10 shows a sheet metal layer according to a fourth embodiment with a third cooling channel variant. R. 415019-1

[0052] - 7 -

[0053] Description of the exemplary implementations

[0054] Fig. 1 shows a partial view of a stator core according to the invention in a first embodiment.

[0055] The stator 1 of an electric machine 2 has a stator core 4 extending around a stator axis 3, which has stator teeth 5 and a stator yoke 7 connecting the stator teeth 5. Stator slots 6 are formed between the stator teeth 5, each having a slot base 8 facing the stator yoke 7 and designed to receive conductors of a stator winding. The stator core 4 comprises a plurality of lamination layers 10 arranged axially with respect to the stator axis 3. The lamination layers 10 of the stator core 4 are, for example, rigidly connected to one another, in particular by interlocks, bonding, or welding.

[0056] Slots 11 are provided in the sheet metal layers 10 to form the stator slots 6. Each slot 11 has a slot base 9 to form a slot base 8. In several sheet metal layers 10, yoke slots 12 are formed in the slot base 9 of the slots 11. These yoke slots extend from the slot base 9 in a radial direction away from the slot 11 with respect to the stator axis 3 into a sheet metal yoke of the respective sheet metal layer 10, and thus into the stator yoke 7. The yoke slots 12 can, for example, be V-shaped.

[0057] According to the invention, it is provided that yoke slots 12 in at least one of the sheet layers 10, in particular in each sheet layer 10, are offset to each other in the circumferential direction relative to yoke slots 12 of at least one adjacent sheet layer 10 in order to avoid an overlap of yoke slots 12 in adjacent sheet layers 10.

[0058] Fig. 2 shows a section through the stator core along line 11-11 in Fig. 1 with a slotted groove base in a stator groove according to the invention.

[0059] The offset of the yoke slots 12 according to the invention is, according to a first embodiment, designed such that in the same stator groove 6 along an axial (partial) extension of the stator groove 6, in particular along a section of the stator groove 6 or along the full length of the stator groove 6, an alternating R. 415019-1

[0060] - 8 -

[0061] A yoke slot 12 is provided in a first slot base position P1 and a yoke slot 12 in a second slot base position P2, wherein the two slot base positions P1, P2 are offset circumferentially by an offset that is less than or equal to the slot width of the stator slot 6. The slot base positions P1, P2 of the yoke slots 12 are each located, for example, at or near one of the two slot base corners of the respective slot 11.

[0062] In other words, several sequences of a yoke slot 12 in a first slot base position P1 and a yoke slot 12 in a second slot base position P2 are provided one after the other in the same stator groove 6 along the superimposed sheet metal layers 10. A sheet metal layer stack is understood to be a group of several sheet metal layers.

[0063] According to the exemplary embodiments, the stator core 4 is formed from at least one spirally wound strip of sheet metal which is wound vertically around the stator axis 3.

[0064] The cross-section of each sheet metal strip has two different area moments of inertia, with the higher of the two area moments of inertia occurring when the sheet metal strip is bent around the stator axis 3. When the respective sheet metal strip is bent, the flanks of the yoke slots 12 are moved towards each other, so that the yoke slots 12 become narrower.

[0065] The lamination layers 10 of the stator core 4 comprise first lamination layers 20 and second lamination layers 30 located between the first lamination layers 20, wherein each second lamination layer 30 has at least one adjacent first lamination layer 20.

[0066] Fig. 3A shows a first sheet layer according to the invention, based on the first embodiment. Fig. 3B shows a second sheet layer according to the invention, based on the first embodiment.

[0067] According to one manufacturing variant, the first lamination layers 20 of the stator core 4 can be formed by a spirally wound first lamination strip 21, and the second lamination layers 30 of the stator core 4 by a spirally wound second lamination strip 31. R. 415019-1

[0068] - 9 -

[0069] According to the first embodiment and the first manufacturing variant, the first sheet metal strip 21 and the second sheet metal strip have a yoke slot 12 in each groove slot 11. According to Fig. 3A, the first sheet metal strip 21 has yoke slots 12 only in the first slot base position P1, and according to Fig. 3B, the second sheet metal strip 31 has yoke slots 12 only in the second slot base position P2. The two slot base positions P1 and P2 are offset from each other circumferentially.

[0070] The first sheet layers 20 and the second sheet layers 30 of the stator core 4 can also be formed by a single spirally wound sheet strip 40 according to an alternative second manufacturing variant.

[0071] According to the first embodiment and the second manufacturing variant, the single spirally wound sheet metal strip 40 has a yoke slot 12 in each groove slot 11. In the first sheet layers 21, as shown in Fig. 3A, the sheet metal strip 40 has only yoke slots 12 in a first slot base position P1, and in the second sheet layers 30, only yoke slots 12 in a second slot base position P2, with the two slot base positions P1, P2 being offset from each other circumferentially. Thus, the sheet metal strip 40 has yoke slots 12 at different slot base positions P1, P2 along its longitudinal extent, depending on the sheet layer. The punching device for manufacturing the sheet metal strip must be designed accordingly.

[0072] The yoke slots 12 have, for example, a radial extent greater than 50% or 60% or 70% or 80% of the radial yoke height of the stator core 4 to improve the bendability of the sheet metal strip 40.

[0073] At several or all yoke slots 12, in particular at the ends of the yoke slots 12 facing away from the groove slots 11, a circumferentially extending channel slot 13 can be provided to form at least one cooling channel 15 extending axially in the stator yoke 7. In the case of yoke slots 12 with channel slots 13, the respective yoke slot 12 including the channel slot 13 has, for example, a radial extent that is greater than 50%, 60%, 70%, or 80% of the radial yoke height of the stator core 4. R. 415019-1

[0074] - 10 -

[0075] The cooling channel 15 can be located in the stator yoke 7 between two adjacent stator teeth 5 according to Fig. 4 or in the stator yoke 7 between two adjacent stator grooves 6 according to Fig. 5.

[0076] To form the respective cooling channel 15, channel slots 13 overlap in adjacent sheet metal layers 10. According to Fig. 4, the overlapping channel slots 13 of the respective cooling channel 15 belong to the same stator groove 6, and according to Fig. 5, to adjacent stator grooves 6.

[0077] Fig. 6 shows a section through a stator core according to the invention with a slotted groove base in a stator groove according to a second embodiment.

[0078] According to a first embodiment, the offset of the yoke slots 12 according to the invention is configured such that, in the same stator groove 6 along the axial (partial) extent of the stator groove 6, a slotted slot base 9, i.e., provided with yoke slots 12, and a slotless slot base 9 are provided alternately from sheet layer 10 to sheet layer 10 or from sheet layer stack to sheet layer stack. In other words, several sequences of a slotted slot base 9, i.e., provided with yoke slots 12, and a slotless slot base 9 are provided one after the other in the same stator groove 6 along the superimposed sheet layers 10.

[0079] According to the second embodiment, the yoke slots 12 in one, in particular each, of the sheet metal layers 10 are offset from the yoke slots 12 in an adjacent sheet metal layer 10 by an offset which corresponds, for example, to a groove pitch.

[0080] Fig. 7A shows a first sheet layer according to the invention in a second embodiment. Fig. 7B shows a second sheet layer according to the invention in the second embodiment.

[0081] According to the second embodiment and the first manufacturing variant, the first lamination layers 20 of the stator core 4 can be formed by a spirally wound first lamination strip 21 and the second lamination layers 30 of the stator core 4 by a spirally wound second lamination strip 31. R. 415019-1

[0082] - 11 -

[0083] According to the second embodiment, both sheet metal strips 21, 31 according to Fig. 7A and Fig. 7B have at least one yoke slot 12 at every second slot 11, in particular two yoke slots 12 at different slot base positions P1, P2, and a slotless slot base 9 at the remaining slots 11. The two sheet metal strips 21, 31 are offset from each other by one slot pitch.

[0084] The first sheet layers 20 and the second sheet layers 30 of the stator core 4 according to the second embodiment can also be formed by a single spirally wound sheet strip 40 according to the second manufacturing variant.

[0085] The single spirally wound sheet metal strip 40 has at least one yoke slot 12 at the slot base 9 of every second slot 11, in particular two yoke slots 12 at different slot base positions P1, P2, and a slotless slot base 9 at the remaining slots 11. The stator 1 has an odd number of stator teeth 5.

[0086] In the second embodiment, a circumferentially extending channel slot 13 can also be provided at several or all of the yoke slots 12, in particular at the ends of the yoke slots 12 facing away from the groove slots 11, to form at least one cooling channel 15 extending axially in the stator yoke 7. The cooling channel 15 is located, for example, in the stator yoke 7 between two adjacent stator grooves 6.

[0087] To form the respective cooling channel 15, channel slots 13 overlap in adjacent sheet metal layers 10. The overlapping channel slots 13 of the respective cooling channel 15 belong, for example, to adjacent stator grooves 6.

[0088] Fig. 8A shows a first manufacturing variant for producing one of the two embodiments of the stator core according to the invention.

[0089] According to the first manufacturing variant, there is a first punching device 25 for producing a first sheet metal strip 21, in particular for punching its slots 11, 12, 13, and a second punching device 26 for producing a second sheet metal strip 31, in particular for punching its slots 11, 12, 13. The two sheet metal strips 21, 22 are wound spirally around the stator shaft 3 such that the first sheet metal layers 20 of the stator core 4 are formed by the spirally wound R. 415019-1

[0090] - 12 - first sheet metal strip 21 and the second sheet metal layers 30 of the stator core 4 are formed by the spirally wound second sheet metal strip 31.

[0091] Fig. 8B shows a second manufacturing variant for producing one of the two embodiments of the stator core according to the invention.

[0092] According to the second manufacturing variant, there is a single punching device 24 for producing a single sheet metal strip 40, in particular for punching its slots 11, 12, 13.

[0093] The single sheet metal strip 40 is wound spirally around the stator axis 3 in such a way that the first sheet metal layers 20 and the second sheet metal layers 30 of the stator core 4 are formed by the single spirally wound sheet metal strip 40.

[0094] In the first embodiment, and also in the second embodiment if the stator has an even number of stator teeth, the punching of the yoke slots 12 and / or the channel slots 13 is dependent on the sheet metal layer and / or requires a change or modification of the punching die. In the second embodiment, if the stator 1 has an odd number of stator teeth 5, the punching of the yoke slots 12 and / or the channel slots 13 is independent of the sheet metal layer and / or requires no change or modification of the punching die.

[0095] Fig. 9 shows a sheet metal layer according to a third embodiment with a third cooling channel variant.

[0096] According to the third embodiment, the yoke slots 12 extend in the respective sheet metal strip 40 along a radial extension in the circumferential direction away from the respective slot base 9 with a curved course.

[0097] In the same stator groove 6, the yoke slots 12 in the first slot base position P1 and the yoke slots 12 in the second slot base position P2 extend in opposite circumferential directions, so that the distance between the yoke slots 12 in the first slot base position P1 and the yoke slots 12 in the second slot base position P2 increases radially outwards.

[0098] According to the third embodiment and a third cooling channel variant, several separate channel slots 13 are formed in the respective sheet metal strip 21, 31 according to R. 415019-1

[0099] - 13 -

[0100] Formation of at least one cooling channel 15 extending axially in the stator yoke 7, which is arranged circumferentially, in particular between the two slot base positions P1, P2 of one of the stator slots 6 and / or radially, in particular between a slot base 8 and an end of the yoke slots 12 facing away from the slot base 8.

[0101] Fig. 10 shows a sheet metal layer according to a fourth embodiment with a third cooling channel variant.

[0102] According to the fourth embodiment, the yoke slots 12 in the respective sheet metal strip 40 extend along a radial extent away from the respective slot base 9, also in a circumferential direction with a curved course.

[0103] In the same stator groove 6, the yoke slots 12 in the first slot base position P1 and the yoke slots 12 in the second slot base position P2 extend in a circumferential direction facing each other, so that the distance between the yoke slots 12 in the first slot base position P1 and the yoke slots 12 in the second slot base position P2 decreases radially outwards.

[0104] In the fourth embodiment, the third cooling channel variant described above is provided.

Claims

R. 415019-1 - 14 - Claims 1. Stator of an electric machine (2) with a stator core (4) having stator teeth (5) and a stator yoke (7) connecting the stator teeth (5), wherein stator grooves (6) are formed between the stator teeth (5), each having a groove base (8) facing the stator yoke (7), wherein the stator core (4) has a plurality of sheet metal layers (10) arranged one above the other in an axial direction with respect to a stator axis (3), wherein slot slots (11) for forming the stator grooves (6) are provided in the sheet metal layers (10), wherein yoke slots (12) are formed in several sheet metal layers (10) in the slot base (9) of slot slots (11), each extending radially away from the slot base (9) and away from the slot slot (11), characterized in that The yoke slots (12) in at least one of the sheet layers (10), in particular in each sheet layer (10), are offset from each other in the circumferential direction to the yoke slots (12) of at least one adjacent sheet layer (10) in order to avoid an overlap of yoke slots (12) in adjacent sheet layers (10).

2. Stator according to claim 1, characterized in that in the same stator groove (6) along an axial extension of the stator groove (6), in particular along a section of the stator groove or along the full length of the stator groove, a yoke slot (12) in a first slot base position (P1) and a yoke slot (12) in a second slot base position (P2) are provided alternately from sheet layer (10) to sheet layer (10) or from sheet layer stack to sheet layer stack, wherein the two slot base positions (P1, P2) are offset in the circumferential direction.

3. Stator according to claim 1, characterized in that in the same stator groove (6) along the axial extent of the stator groove (6) a slotted and a slotless slot base (9) is provided alternately from sheet layer (10) to sheet layer (10) or from sheet layer stack to sheet layer stack.

4. Stator according to one of the preceding claims, characterized in that the stator core (4) is formed from at least one spirally wound strip of sheet metal which is wound upright around the stator axis (3), wherein the R. 415019-1 - 15 - The stator core (4) comprises the first sheet layers (10) and the second sheet layers (30) located between the first sheet layers (20), wherein each second sheet layer (30) has at least one adjacent first sheet layer (20).

5. Stator according to claim 4, characterized in that the first sheet layers (20) of the stator core (4) are formed by a spirally wound first sheet strip (21) and the second sheet layers (30) of the stator core (4) are formed by a spirally wound second sheet strip (31).

6. Stator according to claim 5, characterized in that the first sheet metal strip (21) and the second sheet metal strip (31) have a yoke slot (12) in each slot (11), wherein the first sheet metal strip (21) has only yoke slots (12) in a first slot base position (P1) and the second sheet metal strip (31) has only yoke slots (12) in a second slot base position (P2), wherein the two slot base positions (P1, P2) are offset from each other in the circumferential direction.

7. Stator according to claim 5, characterized in that both sheet metal strips (21 ,31) have at least one yoke slot (12) at every second slot slot (11), in particular two yoke slots (12) at different slot base positions (P1 ,P2), and at remaining slot slots (11) a slotless slot base (9), wherein the two sheet metal strips (21 ,31) are offset from each other by one slot pitch.

8. Stator according to one of claims 1 to 4, characterized in that the first sheet layers (20) and the second sheet layers (30) of the stator core (4) are formed by a single spirally wound sheet strip (40).

9. Stator according to claim 8, characterized in that the single spirally wound sheet metal strip (40) has a yoke slot (12) in each slot (11), wherein the sheet metal strip (40) has only yoke slots (12) in a first slot base position (P1) in the first sheet metal layers (20) and only yoke slots (12) in a second slot base position (P2) in the second sheet metal layers (30), wherein the two slot base positions (P1, P2) are offset from each other in the circumferential direction. R. 415019-1 - 16 - 10. Stator according to claim 8, characterized in that the single spirally wound sheet metal strip (40) at the slot base (9) of each second slot (11) has at least one yoke slot (12), in particular two yoke slots (12) in different slot base positions (P1, P2), and at other slots (11) has a slotless slot base (9), wherein the stator (1) has an odd number of stator teeth (5).

11. Stator according to one of the preceding claims, characterized in that the yoke slots (12) in the respective sheet metal strip (40) extend along a radial extent in the circumferential direction away from the respective slot base (9), in particular with a curved profile.

12. Stator according to claim 11, characterized in that in the same stator groove (6) the yoke slots (12) in the first slot base position (P1) and the yoke slots (12) in the second slot base position (P2) along their radial extension from the groove base (8) radially outwards in circumferential directions away from each other or towards each other.

13. Stator according to one of the preceding claims, characterized in that a circumferentially extending channel slot (13) is formed at several or all yoke slots (12), in particular at the ends of the yoke slots (12) facing away from the groove slots (11), to form at least one cooling channel (15) extending axially in the stator yoke (7), which is located in particular in the stator yoke (7) between two adjacent stator teeth (5) or in the stator yoke (7) between two adjacent stator grooves (6).

14. Stator according to claim 13, characterized in that, to form the respective cooling channel (15), channel slots (13) in adjacent sheet layers (10) overlap, wherein the overlapping channel slots (13) of the respective cooling channel (15) belong to the same stator groove (6) or to adjacent stator grooves (6).

15. Stator according to one of claims 1 to 12, characterized in that several separate channel slots (13) are formed in the respective sheet metal strip (21, 31) to form at least one cooling channel (15) extending axially in the stator yoke (7), which extends circumferentially, in particular between R. 415019-1 - 17 - the two slot base positions (P1 ,P2) of one of the stator slots (6) and / or in a radial direction, in particular between a slot base (8) and an end of the yoke slots (12) facing away from the slot base (8) 16. Stator according to one of the preceding claims, characterized in that adjacent sheet layers (10) of the stator core (4) are firmly connected to each other, in particular by interlocks, gluing or welding.

17. Electric machine (2) with a stator (1) according to one of the preceding claims.

Images