DE-102025129465-A1 - Stator of an electric machine

Abstract

Stator of an electric machine (2) with a stator core (4) comprising 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 the slot base (9) of several sheet metal layers (10), each extending radially away from the slot base (9) of the slot slots (11), characterized in that yoke slots (12) are provided in at least one of the sheet metal layers (10), in particular in each sheet metal layer (10), opposite each other The yoke slots (12) of at least one adjacent sheet layer (10) are offset from each other in the circumferential direction to avoid an overlap of yoke slots (12) in adjacent sheet layers (10).

Inventors

• Kurt Reutlinger
• Jochen Doehring
• Christian Meyer
• Jan Schotte
• Achim Neubauer

Assignees

• Robert Bosch Gesellschaft mit beschränkter Haftung

Dates

Publication Date

20260513

Application Date

20250725

Priority Date

20241108

Claims (17)

1. Stator of an electric machine (2) with a stator core (4) comprising 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 the slot base (9) of several sheet metal layers (10), each extending radially away from the slot base (9) of the slot slots (11), characterized in that yoke slots (12) are located opposite each other in at least one of the sheet metal layers (10), in particular in each sheet metal layer (10). The yoke slots (12) of at least one adjacent sheet layer (10) are offset from each other in the circumferential direction to avoid an overlap of yoke slots (12) in adjacent sheet layers (10).
2. Stator after 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 after 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 sheet metal strip which is wound upright around the stator axis (3), wherein the sheet metal layers (10) of the stator core (4) comprise first sheet metal layers (20) and second sheet metal layers (30) located between the first sheet metal layers (20), wherein each second sheet metal layer (30) has at least one adjacent first sheet metal layer (20).
5. Stator after 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 after 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 groove 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 after Claim 5 , characterized in that both sheet metal strips (21, 31) 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), wherein the two sheet metal strips (21, 31) are offset from each other by one slot pitch.
8. Stator after one of the Claims 1 until 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 after 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.
10. Stator after Claim 8 , characterized in that the single spirally wound sheet metal strip (40) has at least one yoke slot (12), in particular two yoke slots (12) in different slot base positions (P1,P2), at the slot base (9) of every second slot slot (11), and a slotless slot base (9) at the remaining slot slots (11), 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 away from the respective slot base (9) in a circumferential direction extend, especially with a curved course.
12. Stator after 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) extend along their radial extent from the groove base (8) radially outwards in a circumferential direction 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 after 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 after one of the Claims 1 until 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 is arranged in the circumferential direction in particular between the two slot base positions (P1, P2) of one of the stator slots (6) and/or in the 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 metal 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.

Description

State of the art The invention relates to a stator of an electrical machine according to the preamble of the main claim. It is already a stator of an electrical machine from the JP2013093932 A2 A known stator core comprises 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 lamination layers stacked axially with respect to a stator axis, the lamination layers having slots for forming the stator slots. In several lamination layers, yoke slots are formed in the slot base of the slots, each extending radially away from the slot base. The yoke slots in the stator yoke can generate a significant additional magnetic resistance in the stator yoke, since the yoke slots form several axially continuous slots that the magnetic flux can only overcome via an air gap formed by the yoke slots. The increased magnetic resistance impairs the magnetic flux conduction in the stator core, thus reducing the maximum torque and maximum power of the electric machine. Advantages of the invention 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 offsetting yoke slots in at least one of the lamination layers, and in particular in each lamination layer, relative to yoke slots in at least one adjacent lamination layer in the circumferential direction to prevent overlapping of yoke slots in adjacent lamination layers. By preventing overlapping yoke slots, the magnetic flux, when it encounters a yoke slot, can shift to an adjacent lamination layer and thus bypass the respective yoke slot. The yoke slots are designed to facilitate the bending of the sheet metal layers around the stator axis. 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. 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. 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. 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 comprise first layers and second layers situated between the first layers, with each second layer having at least one adjacent first layer. In this way, a vertically wound stator core with low magnetic resistance is achieved. 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. 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, wherein the two slot base positions are offset from each other in the circumferential direction. 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 performed in the first and secon