Stator assembly, electric machine and vehicle

Abstract

This disclosure relates to a stator assembly, a motor, and a vehicle. The stator assembly includes a stator core and a stator winding. The stator core has stator slots, and the stator winding includes multiple layers of flat wire conductors inserted into the stator slots. Each flat wire conductor has a crown end, a welded end, and a straight section within the stator slot. The welded ends of the multiple layers of flat wire conductors are connected, and the connection between the crown end and the straight section is a bend. At least some of the bends in adjacent layers of the multiple layers of flat wire conductors are staggered. In the stator assembly provided by this disclosure, the stress concentration areas and weak insulation parts of adjacent layers of flat wire conductors at the bends are staggered in the axial or circumferential direction, preventing potential damage areas of each layer of conductors from overlapping at the same location. This effectively reduces the risk of insulation damage and failure caused by bending stress concentration, and improves the reliability of winding insulation and the stability of motor operation.

Description

Technical Field

[0001] This disclosure relates to the field of electric motor technology, and more particularly to a stator assembly, an electric motor, and a vehicle. Background Technology

[0002] As a core component of new energy vehicles, improving the copper slot fill factor has become a key research direction in the industry to enhance the motor's efficiency. To achieve a higher slot fill factor, windings have evolved from round wires to flat wires, with multiple layers of flat wire conductors connected within the stator slots to meet the motor's winding wiring requirements.

[0003] In related technologies, during the bending process of flat wire conductors, the bending location is subjected to certain mechanical stress, inevitably causing pre-damage to the winding enamel film. The bending location is a weak point in the stator winding insulation structure. During the operation of the stator winding, electrical stress is generated in the winding. The bending locations of adjacent layers of flat wire conductors are affected by the superimposed electrical stress, which can easily lead to a decrease in the insulation performance of that area, thereby causing insulation failure. This seriously affects the operational reliability of the stator assembly and even the entire motor, shortening the motor's service life. Summary of the Invention

[0004] To overcome the problems existing in the related technologies, this disclosure provides a stator assembly, a motor, and a vehicle.

[0005] According to a first aspect of the present disclosure, a stator assembly is provided, including a stator core and a stator winding. The stator core is provided with stator slots, and the stator winding includes multiple layers of flat wire conductors inserted into the stator slots. Each flat wire conductor has a crown end, a welded end, and a straight segment disposed in the stator slot. The welded ends of the multiple layers of flat wire conductors are connected to each other, and the connection between the crown end and the straight segment is a bend. In the multiple layers of flat wire conductors, at least some of the bends of adjacent layers are staggered.

[0006] In the stator assembly provided in this disclosure, at least some of the bending portions of adjacent layers are staggered, which enables the stress concentration areas and weak insulation parts of the flat wire conductors of adjacent layers to be staggered in the axial or circumferential direction, avoiding the superposition of potential damage areas of flat wire conductors of each layer at the same location, effectively reducing the risk of insulation damage and failure caused by bending stress concentration, and improving the reliability of winding insulation and the stability of motor operation.

[0007] In some possible implementations, the straight segments of the flat conductors in at least some of the adjacent layers are of different lengths, such that the bends in at least some of the adjacent layers are misaligned along the axial direction of the stator core.

[0008] The straight segment lengths of the C and D layers of flat conductors can be greater than (or less than) the straight segment lengths of the other layers, so that the bends of adjacent layers of flat conductors are staggered in axial height, thus offsetting the positions with potential damage and reducing the risk of insulation failure at those positions.

[0009] In some possible implementations, in the multilayer flat wire conductors, the flat wire conductors of adjacent layers are connected across layers to form a winding group, and the two adjacent winding groups are connected by a cross-layer connecting line. The bent portions of the flat wire conductors of adjacent layers in the two adjacent winding groups are arranged in an axially offset manner along the stator core.

[0010] The flat conductors of layers A and B are connected to form the end winding group, the flat conductors of layers F and E are connected to form the end winding group, and the flat conductors of layers C and D are connected to form the intermediate winding group. Calculations show that the point of maximum electrical stress is located between layers B and C and between layers D and E, that is, between the adjacent layers of two adjacent winding groups. By designing the bends of the flat conductors of adjacent layers of adjacent winding groups to be staggered, the magnitude of interphase electrical stress can be reduced.

[0011] In some possible implementations, the plurality of winding groups include end winding groups located at both ends and an intermediate winding group located between the two end winding groups, wherein the lengths of the straight segments of the multilayer flat wire conductors in the intermediate winding group are equal and not equal to the lengths of the straight segments of the multilayer flat wire conductors in the end winding groups.

[0012] There are several ways to achieve staggered arrangement. For example, the bending angle of the bends can be different. The bending angle can be different for all layers, or some layers can be the same and some layers can be different, as long as the adjacent layers of adjacent winding groups are different. Similarly, the lengths of the straight segments can be different. These can be different for multiple layers, or some layers can be the same and some layers can be different. The difference can be greater or less than the specified length, and the specific design can be tailored to the needs.

[0013] In some possible implementations, each of the stator slots is provided with six layers of flat wire conductors, wherein, The straight segments of the third and fourth layers of flat wire conductors are of equal length and longer than the straight segments of the other layers of flat wire conductors; or, The straight segments of the third and fourth layers of flat conductors are of equal length and shorter than the straight segments of the other layers of flat conductors.

[0014] In some possible implementations, each of the stator slots is provided with six layers of flat wire conductors, wherein, The straight segments of the second and fifth layers of flat conductors are of equal length and longer than the straight segments of the other layers of flat conductors; or The lengths of the straight segments of the second and fifth layers of flat conductors are equal and shorter than the lengths of the straight segments of the other layers of flat conductors.

[0015] In some possible implementations, the multiple layers of flat conductors are electrically connected to each other, and there are no in-layer crossover wirings among the flat conductors in each layer.

[0016] In the stator assembly provided in this disclosure, there are no cross-wires in each layer of flat conductors. The winding ends are electrically connected only through interlayer connections. This effectively avoids the problem of radial expansion and inward protrusion of the winding ends caused by the presence of cross-wires in the same layer. It does not encroach on the radial space inside the winding, avoids assembly interference with the rotor, provides sufficient assembly clearance for rotor assembly, and makes the assembly process smoother and more rotor-friendly. At the same time, it does not encroach on the radial space outside the winding, avoids interference and scratching between the oil ring and the winding ends, and significantly improves the convenience and reliability of oil ring assembly.

[0017] In some possible implementations, the stator slot is provided with an even number of layers of flat wire conductors, wherein the flat wire conductors of adjacent layers are connected across layers to form a winding group, and the two adjacent winding groups are connected by a cross-layer connecting line.

[0018] This structure allows for symmetrical and regular arrangement of conductors within the slot, resulting in uniform and symmetrical current paths. This is beneficial for improving the symmetry of the winding magnetomotive force and enhancing the back EMF waveform. At the same time, the symmetrical layered structure facilitates unified end forming and orderly wiring, reduces conductor cross-interference, further optimizes the end spatial layout, and improves assembly consistency and production efficiency.

[0019] In some possible implementations, the winding span of the plurality of flat wire conductors in the winding assembly at the crown end includes a full pitch and a first short pitch.

[0020] The flat conductors at the crown end of the stator winding adopt a span arrangement combining full pitch and first short pitch, which can effectively reduce the types of spans used for flat conductors, simplify the layout logic and wiring structure at the winding ends; at the same time, it can reduce the forming difficulty and processing complexity of flat conductors, unify conductor processing parameters, reduce mold changes and process adjustments, thereby saving raw material consumption, reducing the overall manufacturing cost of the winding, and improving production efficiency and product consistency.

[0021] In some possible implementations, the axial height of the full pitch at the crown end is higher than the axial height of the first short pitch at the crown end.

[0022] In the stator assembly provided in this disclosure, both full-pitch and first short-pitch flat wire conductors are used in the winding group, and the axial height of the full-pitch conductor at the crown end is higher than that of the first short-pitch conductor at the crown end. This retains the advantages of the full-pitch flat wire forming process being simple and easy to manufacture, reducing the difficulty of winding formation; at the same time, the first short-pitch winding can effectively suppress high-order harmonics, improve the NVH performance of the motor, and solve the problems of large harmonics, noise and vibration performance of traditional single full-pitch windings. At the same time, the higher axial height of the crown end of the full-pitch conductor provides sufficient clearance for winding wiring, lead wires and busbar connections, ensuring connection reliability; while the lower axial height of the crown end of the first short-pitch conductor effectively compresses the overall axial dimension of the winding without affecting the overall height of the crown end, improving structural compactness and further reducing the overall space.

[0023] In some possible implementations, the flat conductors of each layer are connected to form a multiphase winding, each phase winding having a lead for connection to a busbar, the full pitch being arranged within the phase band where the lead is located.

[0024] By arranging the full pitch at the lead-out position of each phase winding and making the axial height of the full pitch slightly higher than that of the first short pitch, it is possible to ensure that there is sufficient structural height and arrangement space at the lead-out position to achieve reliable connection between the winding and the busbar, while maintaining a low axial height in the remaining circumferential area, thereby effectively compressing the overall axial space of the motor and improving the structural compactness.

[0025] In some possible implementations, the entire pitch is arranged within the phase band where the lead-out line is located.

[0026] The full pitch is only arranged within the phase band where the lead wire is located, while the first short pitch is used in other positions, with only local elevation. This satisfies the wiring requirements without causing overall bulging. The height of most areas is reduced by using the first short pitch, which significantly compresses the axial space of the motor.

[0027] In some possible implementations, the span of the full pitch is z / 2p, and the span of the first short pitch is z / 2p-1, where z is the number of stator slots and p is the number of stator pole pairs. Flat conductors have fewer span variations to simplify the arrangement, reduce the manufacturing complexity of flat conductors, and lower material costs.

[0028] In some possible implementations, the interlayer connecting lines are arranged with a second short pitch, the span of which is z / 2p-3, where z is the number of stator slots and p is the number of pole pairs of the stator assembly.

[0029] The cross-layer connecting wires adopt a smaller span arrangement, which can effectively shorten the extension length of the winding ends, reduce the axial and radial space occupied at the ends, make the winding end structure more compact and regular, avoid assembly interference with the oil ring, and improve assembly convenience and reliability. At the same time, the smaller span can reduce the cross stacking of conductor ends, which can reduce the difficulty of flat wire forming and bending, reduce conductor material usage, reduce copper loss and production costs, and improve the overall economy and operational stability of the motor.

[0030] In some possible implementations, the cross-layer connector is positioned circumferentially to correspond to the full pitch, and / or the cross-layer connector is located axially below the full pitch.

[0031] It can reduce the axial height of the stator winding, and the cross-layer connecting line and the flat wire conductor of the whole pitch form a compact layout with layered avoidance in space, thereby effectively reducing the space occupied by the winding end in the radial and axial directions, reducing the axial height of the winding, further improving the compactness of the motor structure, and at the same time, it is conducive to reserving sufficient assembly space for the oil ring and improving the assembly processability.

[0032] In some possible implementations, the flat conductor has a crown end, a weld end, and a straight segment disposed in the stator slot, and the weld ends of multiple layers of the flat conductor are interconnected, wherein the connected flat conductors have the same span at the weld end.

[0033] This design optimizes the flat wire twisting forming process, ensuring that the pin positions and heights of the welding ends are uniform and the arrangement is neat after twisting, which facilitates stable clamping and positioning of the welding fixture, effectively improving welding accuracy and quality. At the same time, the uniform pitch specification simplifies the forming and welding processes, reduces tooling debugging and positioning adjustments, shortens the process cycle, and improves production efficiency and product consistency.

[0034] In some possible implementations, the connected flat wire conductors at the welding end have a long pitch span of z / 2p+1, where z is the number of stator slots and p is the number of pole pairs of the stator assembly. This facilitates winding alignment when the welding end is turned. In other embodiments, the span of the connected flat wire conductors at the welding end can be any long pitch greater than the pole pitch, and can be designed as needed.

[0035] In some possible implementations, the stator winding comprises a three-phase winding, with the flat wire conductors of each phase distributed in q+1 stator slots, wherein the flat wire conductors of that phase are arranged only in q-1 stator slots, and q is the number of slots per pole per phase, q≥2. In an embodiment where q=3, taking phase U (shown in green) as an example, the flat wire conductors of this phase are distributed in 4 stator slots, wherein the flat wire conductors of that phase are arranged only in two stator slots, and the flat wire conductors of other phases are arranged in the remaining two stator slots.

[0036] According to a second aspect of the present disclosure, an electric motor is provided, including the stator assembly provided in the above embodiments.

[0037] According to a third aspect of the present disclosure, a vehicle includes an electric motor provided in the present disclosure.

[0038] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Attached Figure Description

[0039] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure.

[0040] Figure 1 This is a schematic diagram of the structure of a stator assembly according to an exemplary embodiment, showing the end face where the crown end is located.

[0041] Figure 2 This is a schematic diagram of the structure of a stator assembly according to an exemplary embodiment, showing the end face where the welding end is located.

[0042] Figure 3 This is a schematic diagram of the structure of a stator assembly according to an exemplary embodiment.

[0043] Figure 4 yes Figure 3 A magnified view of the location of the leader line.

[0044] Figure 5 This is a schematic diagram of the structure of a stator assembly according to an exemplary embodiment, showing a schematic diagram of the connection of the welding ends of one phase winding of layer A and layer B.

[0045] Figure 6 This is a schematic diagram of the structure of a stator assembly according to an exemplary embodiment, showing a schematic diagram of the connection of the crown end of one phase winding of layer A and layer B.

[0046] Figure 7 This is a topological diagram of a stator winding in a stator assembly according to an exemplary embodiment.

[0047] Figure 8 This is a schematic diagram illustrating the connection of one of the layers A and B in a stator assembly according to an exemplary embodiment.

[0048] Figure 9 This is a cross-sectional view of a stator assembly according to an exemplary embodiment.

[0049] Figure 10 This is a cross-sectional view of a stator assembly according to an exemplary embodiment.

[0050] Figure 11 This is a cross-sectional view of a stator assembly according to an exemplary embodiment.

[0051] Figure 12 This is a comparison chart of torque fluctuations for different winding schemes.

[0052] Figure 13 This is a diagram showing the order of torque pulsation for different winding schemes.

[0053] Figure 14 These are harmonic analysis diagrams for different winding schemes.

[0054] Explanation of reference numerals in the attached figures 1-Stator core; 11-Stator slot; 2-Stator winding; 20-Flat conductor; 21-Winding assembly; 211-End winding assembly; 212-Intermediate winding assembly; 22-Interlayer connecting wire; 23-Lead-out wire; 200-Bending section; 201-Crown end; 202-Welding end; 203-Straight section; 31-Full pitch; 32-First short pitch; 33-Second short pitch; 34-Long pitch. Detailed Implementation

[0055] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this disclosure as detailed in the appended claims.

[0056] In this disclosure, unless otherwise stated, directional terms such as "axial" and "radial" generally refer to those relative to the central axis of the stator core in the motor provided in this disclosure, and "inner" and "outer" may refer to the inner and outer contours of the corresponding component or its location within or outside its environment, depending on the specific context. Furthermore, when the following description relates to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The terms "first," "second," etc., used in this disclosure are for distinguishing one element from another and do not have sequential or material significance.

[0057] To facilitate understanding, we will first explain and clarify the terms related to windings.

[0058] The number of magnetic poles, the number of poles in the stator. Magnetic poles are divided into N poles and S poles. Generally, one N pole and one S pole are called a pair of magnetic poles, that is, the number of pole pairs is 1. Therefore, the number of pole pairs in the stator is... If the pole numbers are 1, 2, 3, and 4, then the pole numbers of the stator are 2, 4, 6, and 8.

[0059] Pole moment is the distance between the center of one magnetic pole and the center of the next magnetic pole of the same name. , where z is the number of stator slots 11 and p is the number of pole pairs.

[0060] Pitch refers to the distance that the two effective sides of a coil span on the stator, and this distance is usually expressed in terms of the number of slots.

[0061] Number of phases in stator winding: m, commonly m=3.

[0062] The number of stator slots per pole per phase, q, is the number of stator slots occupied by each phase under each magnetic pole, q=z / 2pm.

[0063] Phase band: The collection of conductors within each pole and each phase slot.

[0064] Number of parallel winding branches: a.

[0065] Number of conductors per slot: w.

[0066] Full-pitch windings refer to winding types where the coil pitch is equal to the pole pitch. Most existing flat wire motor stator windings are full-pitch windings. Full-pitch windings suffer from large torque fluctuations during use, leading to a decrease in the motor's NVH performance.

[0067] Short-pitch windings refer to winding types where the coil pitch is smaller than the pole pitch. They can reduce higher harmonics, improve back EMF waveforms, and reduce losses.

[0068] Long-pitch windings refer to winding types where the coil pitch is greater than the pole pitch. Similar to short-pitch windings, they can also reduce higher harmonics and improve the back EMF waveform.

[0069] Figures 1 to 6 This is a schematic diagram of the structure of a stator assembly according to an exemplary embodiment, wherein, Figure 1 The end face where crown end 201 is located is shown. Figure 2 The end face where welding end 202 is located is shown. Figure 3 This shows one end where the lead 23 for connection to the busbar is located. Figure 4 yes Figure 3 A magnified view of the area at position 23 of the leader line. Figure 5 This diagram shows the connection schematic of the welding end 202 of one phase winding in layers A and B. Figure 6 A schematic diagram of the connection of the crown end 201 of one phase winding in layers A and B is shown. Figure 7 This is a topological diagram of a stator winding in a stator assembly according to an exemplary embodiment.

[0070] Figure 8This is a schematic diagram illustrating the connection of one phase of layer A and layer B in a stator assembly according to an exemplary embodiment. (Refer to...) Figure 8 During the bending process of the flat wire conductor 20, a bend 200 is formed at the connection between the crown end 201 and the straight section 203. The bend 200 is subjected to mechanical stress, inevitably causing pre-damage to the winding enamel film. The location of the bend 200 is a weak point in the insulation structure of the stator winding 2. During the operation of the stator winding 2, electrical stress is generated in the winding. The bends 200 of adjacent layers of flat wire conductor 20 are affected by superimposed electrical stress, which easily leads to a decrease in the insulation performance of this area, thereby causing insulation failure. This seriously affects the operational reliability of the stator assembly and even the entire motor, shortening the motor's service life.

[0071] To solve the problem of insulation failure, refer to Figure 10 In this disclosure, a stator assembly is provided, which includes a stator core 1 and a stator winding 2. The stator core 1 is provided with a stator slot 11. The stator winding 2 includes multiple layers of flat wire conductors 20 inserted into the stator slot 11. The flat wire conductors 20 have a crown end 201, a welding end 202 and a straight segment 203 provided in the stator slot 11. The welding ends 202 of the multiple layers of flat wire conductors 20 are connected. The connection between the crown end 201 and the straight segment 203 is a bend 200. In the multiple layers of flat wire conductors 20, at least some of the bends 200 of adjacent layers are staggered.

[0072] Here, the staggered arrangement can be arranged axially offset. Figure 10 In the illustrated embodiment, the straight segments 203 of the flat conductors in layers C and D are slightly longer than those in layers A, B, E, and F. In the same cross-section, layers A, B, E, and F cut at the locations of the bends 200, while layers C and D cut at the locations of the straight segments 203, resulting in different axial positions of the bends 200 in adjacent layers. Of course, this disclosure also includes circumferentially staggered arrangements, where the bends 200 of adjacent layers have different bending radii, thus achieving a staggered arrangement. Furthermore, the arrangement can be between any two adjacent layers, or between partially adjacent layers, all of which fall within the scope of this disclosure.

[0073] This design allows the stress concentration areas and weak insulation parts of adjacent layers of flat conductors 20 at the bends to be staggered in the axial or circumferential direction, avoiding the superposition of potential damage areas of each layer of flat conductors 20 at the same location, effectively reducing the risk of insulation damage and failure caused by bending stress concentration, and improving the reliability of winding insulation and the stability of motor operation.

[0074] In the embodiments provided in this disclosure, the straight segments 203 of the flat conductors 20 in at least some adjacent layers are of different lengths, so that the bent portions 200 in at least some adjacent layers are misaligned along the axial direction of the stator core 1.

[0075] In an exemplary embodiment of this disclosure, the length of the straight segment 203 of the flat conductors 20 of the C layer and the D layer can be greater than the length of the straight segment of the other layers, so that the bends 200 of the two adjacent flat conductors are staggered in axial height, thus offsetting the position of potential damage and reducing the risk of insulation failure at that position.

[0076] In an exemplary embodiment of this disclosure, the length of the straight segments 203 of the flat conductors 20 in layers C and D can be less than the length of the straight segments in the other layers, so that the bends 200 of the two adjacent layers of flat conductors are staggered in axial height, thus offsetting the positions where pre-damage is expected and reducing the risk of insulation failure at those positions.

[0077] The specific staggered arrangement of the layers can be designed appropriately based on the connection configuration of the stator windings 2. In this disclosure, in the multilayer flat conductors 20, the flat conductors 20 of adjacent layers are connected across layers to form winding groups 21. The two adjacent winding groups 21 are connected by a cross-layer connecting line 22. The bent portions 200 of the flat conductors 20 of adjacent layers in the two adjacent winding groups 21 are staggered along the axial direction of the stator core 1. Here, the flat conductors of layers A and B are connected to form end winding groups 211, the flat conductors of layers F and E are connected to form end winding groups 211, and the flat conductors of layers C and D are connected to form intermediate winding groups 212. Calculations show that the point of maximum electrical stress is located between layers B and C and between layers D and E, that is, between adjacent layers of the two adjacent winding groups 21. By designing the bent portions 200 of the flat conductors 20 of adjacent layers of the adjacent winding groups 21 to be staggered, the magnitude of interphase electrical stress can be reduced.

[0078] There are several ways to achieve staggered arrangement. For example, the bending angles of the bending section 200 can be different. The bending angles can be different in all layers, or some layers can be the same and some layers can be different, as long as the adjacent layers of adjacent winding groups 21 are different. Similarly, the lengths of the straight segments 203 can be different. They can be different in multiple layers, or some layers can be the same and some layers can be different. The difference can be greater or less than the specified length, and the specific design can be customized according to the needs.

[0079] In this disclosure, the plurality of winding groups 21 include end winding groups 211 located at both ends and an intermediate winding group 212 located between the two end winding groups 211. The lengths of the straight segments 203 of the multilayer flat wire conductors 20 in the intermediate winding group 212 are equal, but not equal to the lengths of the straight segments 203 of the multilayer flat wire conductors 20 in the end winding groups 211. In this embodiment, the lengths of the straight segments 203 of the C-layer and D-layer flat wire conductors 20 may be equal and not equal to the lengths of the straight segments 203 of the flat wire conductors 20 in other layers. In other embodiments, the lengths of the straight segments 203 of the C-layer and D-layer may also be different, all of which fall within the protection scope of this disclosure.

[0080] In an exemplary embodiment of this disclosure, each stator slot 11 is provided with 6 layers of flat wire conductors, wherein the lengths of the straight segments 203 of the third layer of flat wire conductors (C layer) and the fourth layer of flat wire conductors (D layer) are equal and greater than the lengths of the straight segments 203 of the other layers of flat wire conductors.

[0081] In an exemplary embodiment of this disclosure, each stator slot 11 is provided with 6 layers of flat wire conductors 20, wherein the lengths of the straight segments 203 of the third layer of flat wire conductors (C layer) and the fourth layer of flat wire conductors (D layer) are equal and less than the lengths of the straight segments 203 of the other layers of flat wire conductors.

[0082] In an exemplary embodiment of this disclosure, each stator slot 11 is provided with 6 layers of flat wire conductors 20, wherein the lengths of the straight segments 203 of the second layer of flat wire conductors (B layer) and the fifth layer of flat wire conductors (E layer) are equal and greater than the lengths of the straight segments 203 of the other layers of flat wire conductors.

[0083] In an exemplary embodiment of this disclosure, each stator slot 11 is provided with 6 layers of flat wire conductors 20, wherein the lengths of the straight segments 203 of the second layer of flat wire conductors (B layer) and the fifth layer of flat wire conductors (E layer) are equal and shorter than the lengths of the straight segments 203 of the other layers of flat wire conductors.

[0084] Reference Figures 1 to 7 In the stator assembly provided in this disclosure, the span of the plurality of flat wire conductors 20 in the winding group 21 at the crown end 201 is a full pitch 31 and a first short pitch 32, as shown in the reference. Figure 4 The axial height of the full pitch 31 at the crown end 201 is higher than the axial height of the first short pitch 32 at the crown end 201.

[0085] In the stator assembly provided in this disclosure, the winding group 21 employs flat wire conductors 20 with both full pitch 31 and first short pitch 32. The axial height of the full pitch 31 at the crown end 201 is higher than that of the first short pitch 32 at the crown end 201. This retains the advantages of the full pitch 31's simple flat wire forming process and ease of manufacturing, reducing the difficulty of winding formation. Simultaneously, the first short pitch 32 effectively suppresses high-order harmonics, improving the motor's NVH performance and solving the problems of high harmonics, noise, and vibration performance in traditional single-pitch windings. Furthermore, the higher axial height of the crown end 201 of the full pitch 31 provides sufficient clearance for the lead wires 23 and busbar connections, ensuring connection reliability without affecting the overall height of the crown end 201. Conversely, the lower axial height of the crown end 201 of the first short pitch 32 effectively compresses the overall axial dimension of the winding, improving structural compactness and further reducing overall space.

[0086] In this disclosure, reference is made to Figure 4 and Figure 7 The flat conductors 20 of each layer are connected to form a multi-phase winding. Each phase winding has a lead 23 for connection with the busbar. The full pitch 31 is arranged within the phase band where the lead 23 is located. By arranging the full pitch 31 at the position of the lead 23 of each phase winding, and making the axial height of the full pitch 31 slightly higher than the axial height of the first short pitch 32, it is possible to ensure that there is sufficient structural height and arrangement space at the position of the lead 23 to achieve a reliable connection between the winding and the busbar, while maintaining a low axial height in the remaining circumferential area, thereby effectively compressing the overall axial space of the motor and improving the structural compactness.

[0087] Reference Figure 7 At the crown end 201, the entire pitch 31 is arranged within the phase band where the lead wire 23 is located, while the first short pitch 32 is arranged in other phase bands outside the lead wire 23. By arranging the entire pitch 31 only within the phase band where the lead wire 23 is located, and using the first short pitch 32 in other positions, only local elevation is achieved, which satisfies the wiring requirements without causing overall bulging. The height of most areas is reduced by using the first short pitch 32, significantly compressing the axial space of the motor. In other embodiments, the entire pitch 31 can also be arranged in other phase bands outside the lead wire 23. The specific design can be customized as needed, and all of these fall within the protection scope of this disclosure.

[0088] Reference Figure 7 The multi-layer flat conductors 20 are electrically connected to each other, and there are no crossover wires in the same layer of flat conductors. That is, each layer of flat conductors 20 adopts a cross-layer connection method, and there are no crossover wires in the same layer of flat conductors 20.

[0089] Here, it should be noted that, with Figure 7 and Figure 10Taking the illustrated embodiment as an example, the stator slot 11 is provided with six layers of flat wire conductors 20, w=6, which are layer A, layer B, layer C, layer D, layer E and layer F from the inside out. In related technologies, layer A or layer F may have cross-wires within the same layer. The cross-wires within layer A will protrude inward, which will additionally encroach on the radial inner space of the winding and affect the assembly of the rotor. The cross-wires within layer F will bulge outward at the winding ends, which will encroach on the radial outer space of the winding and affect the assembly of the oil rings at both ends. Of course, this disclosure does not limit the number of layers of flat wire conductors 20, and embodiments with any even number of layers are within the protection scope of this disclosure.

[0090] In the stator assembly provided in this disclosure, there are no cross-wires in each layer of flat wire conductors 20. The winding ends are electrically connected only through interlayer connections. This effectively avoids the problem of radial expansion and inward protrusion of the winding ends caused by the presence of cross-wires in the same layer. It does not encroach on the radial space inside the winding, avoids assembly interference with the rotor, provides sufficient assembly clearance for rotor assembly, and makes the assembly process smoother and more rotor-friendly. At the same time, it does not encroach on the radial space outside the winding, avoids interference and scratching between the oil ring and the winding ends, and significantly improves the convenience and reliability of oil ring assembly.

[0091] Figure 8 This is a schematic diagram illustrating the connection of one phase of layer A and layer B in a stator assembly according to an exemplary embodiment. (Refer to...) Figure 5 , Figure 6 and Figure 8 As shown, the flat wire conductor 20 has a crown end 201, a welding end 202, and a straight section 203 disposed in the stator slot 11. The crown end 201 of the multilayer flat wire conductor 20 is inserted into the corresponding stator slot 11 and connected to each other at the welding end 202 to realize the electrical connection of the stator winding 2.

[0092] In the exemplary embodiments provided in this disclosure, an even number of layers of flat wire conductors 20 are provided in the stator slot 11. Adjacent layers of flat wire conductors 20 are connected across layers to form winding groups 21, and adjacent winding groups 21 are connected by cross-layer connecting lines 22. In an embodiment with six layers of flat wire conductors 20, refer to... Figure 7The flat wire conductors 20 of layers A and B are connected to form the first winding group (end winding group 211), the flat wire conductors 20 of layers C and D are connected to form the second winding group (middle winding group 212), and the flat wire conductors 20 of layers E and F are connected to form the third winding group (end winding group 211). The first and second winding groups are connected by a first interlayer connecting line, and the second and third winding groups are connected by a second interlayer connecting line. The specific design can be tailored to the number of layers of flat wire conductors 20. This structure allows for symmetrical and orderly arrangement of conductors within the slot, resulting in a uniform and symmetrical current path. This improves the symmetry of the winding magnetomotive force and reduces the back EMF waveform. Simultaneously, the symmetrical layered structure facilitates unified end forming and orderly wiring, reduces conductor cross-interference, further optimizes the end spatial layout, and improves assembly consistency and production efficiency. (Reference) Figure 7 The embodiment shown illustrates the connection topology of one branch of the U phase, where the solid line represents the routing of the flat conductor 20 at the crown end 201, and the dashed line represents the routing of the flat conductor 20 at the welding end 202.

[0093] The routing of one branch of the U phase is as follows: Take the F layer of slot 53 (hereinafter referred to as 53-F; other locations can be referred to in this example) as the starting point. (It should be noted that the starting and ending points of the windings in actual products may differ from this example; they can be equivalently moved to any point on the loop to obtain a set of leads as the starting and ending points of the windings.) Connect the welded end to 43-E, the crown end to 35-F, the welded end to 25-E, the crown end to 17-F, the welded end to 7-E, and the crown end to 52-... F, bridging to 42-E at the welding end, bridging to 34-F at the crown end, bridging to 24-E at the welding end, bridging to 16-F at the crown end, bridging to 6-E at the welding end, bridging to 51-F at the crown end, bridging to 41-E at the welding end, bridging to 33-F at the crown end, bridging to 23-E at the welding end, bridging to 15-F at the crown end, bridging to 5-E at the welding end, bridging to 53-D at the crown end, bridging to 43-C at the welding end, bridging to 35-D at the crown end, bridging to 25-C at the welding end, bridging to 1 at the crown end. 7-D, bridging to 7-C at the welding end, bridging to 52-D at the crown end, bridging to 42-C at the welding end, bridging to 34-D at the crown end, bridging to 24-C at the welding end, bridging to 16-D at the crown end, bridging to 6-C at the welding end, bridging to 51-D at the crown end, bridging to 41-C at the welding end, bridging to 33-D at the crown end, bridging to 23-C at the welding end, bridging to 15-D at the crown end, bridging to 5-C at the welding end, bridging to 53-B at the crown end, bridging to 43-A at the welding end, bridging to... Connect the 35-B to 25-A at the welding end, connect the crown end to 17-B, connect the welding end to 7-A, connect the crown end to 52-B, connect the welding end to 42-A, connect the crown end to 34-B, connect the welding end to 24-A, connect the crown end to 19-B, connect the welding end to 6-A, connect the crown end to 51-B, connect the welding end to 41-C, connect the crown end to 33-B, connect the welding end to 23-A, connect the crown end to 15-B, and connect the welding end to 5-A, thus forming a branch. Another branch can be formed by filling in the gaps in the remaining windings using the same principle.

[0094] Taking the connection between layers F and E as an example, in the third winding group (end winding group 211), the span from 53-F to 43-E is 10 and at the welding end 202 (the welding end is a long pitch), the span from 43-E to 35-F is 8 and at the crown end 201 (the crown end is the first short pitch), the span from 35-F to 25-E is 10 and at the welding end (the welding end is a long pitch), the span from 25-E to 17-F is 8 and at the crown end 201 (the crown end is the first short pitch), and the span from 17-F to 7-E is... The distance is 10 and at the welding end 202 (the welding end is the long pitch), the span from 7-E to 52-F is 9 and at the crown end 201 (the crown end is the first short pitch)... Then, from 5-E to 53-D (the cross-layer connection line 22 from layer E to layer D, the span is 6, which is the second short pitch), then connect multiple flat conductors of layer D and layer C, then from 5-C to 53B (the cross-layer connection line 22 from layer C to layer B, the span is 6, which is the second short pitch), then connect multiple flat conductors of layer A and layer B.

[0095] In this embodiment, p=3, z=54, m=3, w=6, a=2, q=3, and the polar distance is... =54 / 2*3=9, the winding span of the multiple flat conductors 20 in the winding group 21 at the crown end 201 can be either 8 or 9. In this disclosure, the winding span of the multiple flat conductors 20 in the winding group 21 at the crown end 201 includes a full pitch 31 and a first short pitch 32. The flat conductors 20 of the stator winding 2 at the crown end 201 adopt a span arrangement combining a full pitch 31 and a first short pitch 32, which can effectively reduce the types of spans used for the flat conductors 20, simplify the arrangement logic and wiring structure of the winding ends; at the same time, it can reduce the forming difficulty and processing complexity of the flat conductors 20, unify conductor processing parameters, reduce mold changes and process debugging, thereby saving raw material consumption, reducing the overall manufacturing cost of the winding, and improving production efficiency and product consistency.

[0096] The span of the full pitch 31 is z / 2p (9 in this embodiment), and the span of the first short pitch 32 can be z / 2p-1 (8 in this embodiment), where z is the number of stator slots and p is the number of pole pairs in the stator assembly. The flat conductor 20 has fewer span types to simplify its arrangement, reduce the manufacturing complexity of the flat conductor 20, and lower material costs. In other embodiments, short pitches with a span smaller than the pole pitch are all within the scope of this disclosure; the span of the first short pitch 32 can be designed as needed.

[0097] In an exemplary embodiment of this disclosure, the cross-layer connection 22 from layer E to layer D has a span of 6, and the cross-layer connection 22 from layer C to layer B also has a span of 6. In this disclosure, the cross-layer connection 22 is arranged with a second short pitch 33, the span of which is z / 2p-3, where z is the number of stator slots and p is the number of pole pairs in the stator assembly. The smaller span arrangement of the cross-layer connection 22 effectively shortens the extension length of the winding ends, reduces the axial and radial space occupied at the ends, makes the winding end structure more compact and regular, avoids assembly interference with the oil ring, and improves assembly convenience and reliability. Simultaneously, the smaller span reduces conductor end cross-stacking, reduces the difficulty of flat wire forming and bending, reduces conductor material usage, lowers copper loss and production costs, and improves the overall economy and operational stability of the motor. In other embodiments, the second short pitch 33 with a span smaller than the pole pitch is also within the scope of this disclosure, and the span of the cross-layer connection 22 can be designed according to specific needs.

[0098] refer to Figure 7 The cross-layer connection line 22 from layer E to layer D and the cross-layer connection line 22 from layer C to layer B correspond in the circumferential direction to the flat conductor 20 with a span of 9. In this disclosure, the cross-layer connection line 22 corresponds in the circumferential direction to the flat conductor with a full pitch of 31. Figure 7 This is a cross-sectional view of a stator assembly according to an exemplary embodiment. In embodiments of this disclosure, reference is made to... Figure 7 Under the same cross-sectional plane, the interlayer connecting line 22 remains intact, while the other flat conductors 20 have been cut. It can be seen that the interlayer connecting line 22 is located axially below the full pitch 31. This can reduce the axial height of the stator winding 2. The interlayer connecting line 22 and the flat conductors 20 of the full pitch 31 form a compact layout with layered avoidance in space, thereby effectively reducing the space occupied by the winding ends in the radial and axial directions, reducing the axial height of the winding, further improving the compactness of the motor structure, and at the same time, it is beneficial to reserve sufficient assembly space for the oil ring and improve the assembly processability.

[0099] Reference Figure 5 The connected flat wire conductors 20 have the same span at the welding end 202. This optimizes the flat wire twisting process, ensuring that the pin positions at the welding end are uniform in height and neatly arranged after twisting, facilitating stable clamping and positioning of the welding fixture, and effectively improving welding accuracy and quality. At the same time, the uniform pitch specification simplifies the forming and welding processes, reduces fixture debugging and positioning adjustments, shortens the process cycle, and improves production efficiency and product consistency.

[0100] In this disclosure, the span of the connected flat wire conductors 20 at the welding end 202 is a long pitch 34, and the span of the long pitch 34 is z / 2p+1, where z is the number of stator slots and p is the number of pole pairs of the stator assembly. In this embodiment, the span of the welding end 202 is 10, which is beneficial for winding alignment when the welding end is turned. In other embodiments, the span of the connected flat wire conductors 20 at the welding end 202 can be any long pitch greater than the pole pitch, and can be designed according to specific needs.

[0101] Figure 11 This is a cross-sectional view of a stator assembly according to an exemplary embodiment. (Refer to...) Figure 11 As shown, the stator winding includes a three-phase winding. The flat wire conductors of each phase are distributed in q+1 stator slots 11. Among them, the flat wire conductors of that phase are arranged only in q-1 stator slots. q is the number of slots per pole per phase, q=z / 2pm≥2. In this embodiment, q=3. Taking the green U phase as an example, the flat wire conductors of this phase are distributed in 4 stator slots 11. Among them, the flat wire conductors of that phase are arranged only in two stator slots 11, and the flat wire conductors of other phases are arranged in the remaining two stator slots 11.

[0102] Figure 12 This is a comparison chart of torque fluctuations for different winding schemes. Figure 13 This is a diagram showing the order of torque pulsation for different winding schemes. Figure 14 These are harmonic analysis diagrams for different winding schemes.

[0103] Reference Figures 12 to 14 Electromagnetic simulations show that, compared to traditional full-pitch windings, the stator winding pairs provided in this disclosure significantly reduce the 5th, 7th, and 11th harmonics. (Refer to...) Figure 12 Compared to traditional full-pitch solutions, the torque ripple of the stator winding 2 provided in the embodiments of this disclosure can be reduced by approximately 0.2%. (Refer to...) Figure 13 This significantly improves the performance of 18th and 36th order short-torque ripples. Compared to traditional full-pitch solutions, the torque ripple in this embodiment can be reduced by approximately 1.3 Nm. (Refer to...) Figure 14 Compared with traditional full-pitch solutions, the winding arrangement provided in this embodiment can significantly reduce harmonic content, optimize torque pulsation and torque fluctuation, thereby improving NVH performance.

[0104] According to a second aspect of this disclosure, an electric motor is provided, including the stator assembly described in the different embodiments above.

[0105] In the motor disclosed herein, the stator winding 2 has no cross-wires in the same layer, thus not encroaching on the inner diameter space of the winding. This ensures that the inner diameter of the stator core 1 is not invaded by the stator winding 2, and the rotor can be assembled from both ends of the stator core 1, thereby improving assemblability. At the same time, it does not encroach on the outer diameter space of the stator winding 2, ensuring that the stator oil ring can be assembled on the end face of the stator core 1. The stator winding 2 has fewer types of flat wire conductors 20, which simplifies the arrangement, reduces the manufacturing complexity of the flat wire conductors 20, and reduces material costs. The welding ends 202 of the stator winding 2 are all long pitch 34 with a pitch of 10, which is beneficial for twisting and forming, as well as the consistency of the position of the welding ends 202 after twisting. This is beneficial for winding alignment when the welding ends 202 are twisted, facilitates the application of welding fixtures, improves welding quality, and reduces the cycle time. The cross-layer connecting wire 22 of the crown end 201 adopts the second short pitch 33 and is located below the full pitch 31 in 3D space, which can reduce the winding cross-sectional height. The straight segment 203 of the flat wire conductors of layers C and D is slightly longer than the straight segment of the flat wire conductors of layers A, B, E, and F, so that the bending part 200 of the adjacent layer flat wire conductors is misaligned in axial space, reducing the risk of insulation failure at that location.

[0106] Furthermore, in the motor provided in this disclosure, the winding assembly 21 uses flat wire conductors 20 with both full pitch 31 and first short pitch 32 at the crown end 201. The axial height of the full pitch 31 at the crown end 201 is higher than that of the first short pitch 32 at the crown end 201. This retains the advantages of the full pitch 31 flat wire forming process being simple and easy to manufacture, reducing the difficulty of winding formation. Simultaneously, the first short pitch 32 effectively suppresses high-order harmonics, improving the motor's NVH performance and solving the problems of large harmonics, noise, and vibration performance in traditional single-pitch windings. Additionally, the higher axial height of the crown end 201 of the full pitch 31 provides sufficient clearance for the lead wire 23 and busbar connections, ensuring connection reliability without affecting the overall height of the crown end 201. Conversely, the lower axial height of the crown end 201 of the first short pitch 32 effectively compresses the overall axial dimension of the winding, improving structural compactness and further reducing the overall space.

[0107] According to a third aspect of this disclosure, a vehicle is provided, including the motor provided herein. The vehicle has all the beneficial effects of the described motor and stator assembly, which will not be repeated here.

Claims

1. A stator assembly, characterized in that, The device includes a stator core and a stator winding. The stator core has stator slots, and the stator winding includes multiple layers of flat wire conductors inserted into the stator slots. Each flat wire conductor has a crown end, a welded end, and a straight section within the stator slot. The welded ends of the multiple layers of flat wire conductors are connected, and the connection between the crown end and the straight section is a bend. In the multilayer flat conductor, at least some of the bends in adjacent layers are arranged in a staggered manner.

2. The stator assembly according to claim 1, characterized in that, The straight segments of the flat conductors in at least some adjacent layers are of different lengths, such that the bent portions in at least some adjacent layers are misaligned along the axial direction of the stator core.

3. The stator assembly according to claim 2, characterized in that, In the multilayer flat wire conductor, the flat wire conductors of two adjacent layers are connected across layers to form a winding group. The two adjacent winding groups are connected by a cross-layer connecting line. The bent portions of the flat wire conductors of adjacent layers in the two adjacent winding groups are arranged in a staggered manner along the axial direction of the stator core.

4. The stator assembly according to claim 3, characterized in that, The plurality of winding groups include end winding groups located at both ends and intermediate winding groups located between the two end winding groups, wherein the lengths of the straight segments of the multilayer flat wire conductors in the intermediate winding group are equal and not equal to the lengths of the straight segments of the multilayer flat wire conductors in the end winding groups.

5. The stator assembly according to claim 4, characterized in that, Each of the stator slots is provided with 6 layers of flat wire conductors, wherein... The straight segments of the third and fourth layers of flat wire conductors are of equal length and longer than the straight segments of the other layers of flat wire conductors; or, The straight segments of the third and fourth layers of flat conductors are of equal length and shorter than the straight segments of the other layers of flat conductors.

6. The stator assembly according to claim 4, characterized in that, Each of the stator slots is provided with 6 layers of flat wire conductors, wherein... The straight segments of the second and fifth layers of flat conductors are of equal length and longer than the straight segments of the other layers of flat conductors; or The lengths of the straight segments of the second and fifth layers of flat conductors are equal and shorter than the lengths of the straight segments of the other layers of flat conductors.

7. The stator assembly according to any one of claims 1-6, characterized in that, The flat conductors in the multiple layers are electrically connected to each other, and there are no crossover wirings between the flat conductors in each layer.

8. The stator assembly according to claim 7, characterized in that, The stator slot is provided with an even number of layers of flat wire conductors, wherein the flat wire conductors of two adjacent layers are connected across layers to form a winding group, and two adjacent winding groups are connected by a cross-layer connecting line.

9. The stator assembly according to claim 8, characterized in that, The winding span of the multiple flat conductors in the winding assembly at the crown end includes the full pitch and the first short pitch.

10. The stator assembly according to claim 9, characterized in that, The axial height of the full pitch at the crown end is higher than the axial height of the first short pitch at the crown end.

11. The stator assembly according to claim 10, characterized in that, The flat conductors of each layer are connected to form a multiphase winding, and each phase winding has a lead for connection to a busbar, with the full pitch arranged within the phase band where the lead is located.

12. The stator assembly according to claim 11, characterized in that, The entire pitch is arranged within the phase band where the lead-out line is located.

13. The stator assembly according to claim 9, characterized in that, The span of the full pitch is z / 2p, and the span of the first short pitch is z / 2p-1, where z is the number of stator slots and p is the number of stator pole pairs.

14. The stator assembly according to claim 13, characterized in that, The cross-layer connecting line adopts a second short pitch arrangement, and the span of the second short pitch is z / 2p-3, where z is the number of stator slots and p is the number of pole pairs of the stator assembly.

15. The stator assembly according to claim 9, characterized in that, The cross-layer connecting line is positioned circumferentially to correspond to the full pitch, and / or the cross-layer connecting line is located axially below the full pitch.

16. The stator assembly according to claim 1, characterized in that, The connected flat wire conductors have the same span at the welded ends.

17. The stator assembly according to claim 16, characterized in that, The connected flat wire conductors have a long pitch span at the welding end, and the long pitch span is z / 2p+1, where z is the number of stator slots and p is the number of pole pairs of the stator assembly.

18. The stator assembly according to claim 1, characterized in that, The stator winding includes a three-phase winding, with the flat wire conductors of each phase distributed in q+1 stator slots, wherein only the flat wire conductors of that phase are arranged in q-1 stator slots, where q is the number of slots per pole per phase, and q≥2.

19. An electric motor, characterized in that, Includes the stator assembly according to any one of claims 1-18.

20. A vehicle, characterized in that, Includes the motor as described in claim 19.

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