Flat wire stator assembly and motor

Abstract

The present invention discloses a flat wire stator assembly and a motor, including a stator core and a stator winding. All hairpin coils are divided into a first hairpin coil group, a second hairpin coil group, and a third hairpin coil group. The hairpin coils in the first hairpin coil group are located in the first layer, the hairpin coils in the second hairpin coil group are evenly distributed in the Tth, (T + 1)th,..., (L - 1)th layers respectively, and the hairpin coils in the third hairpin coil group are located in the Lth layer; the stator winding includes M parallel sub-windings formed by series connection of hairpin coils distributed in different mounting slots, different magnetic poles, and different layers, and each of the sub-windings is formed by series connection of some or all of the hairpin coils in each of the first hairpin coil group, the second hairpin coil group, and the third hairpin coil group. The present invention has the effects of fewer types of hairpin coils, simple forming structure of the stator assembly, and convenient production and manufacturing.

Description

Technical Field

[0001] The present invention relates to the technical field of motor manufacturing, and particularly to a flat wire stator assembly and a motor. Background Art

[0002] In recent years, the electric vehicle industry has developed vigorously. As one of the key components of electric vehicles, the vehicle drive motor has also achieved great development, and its performance is crucial for the performance of the whole vehicle. At present, vehicle motors are developing towards high speed, light weight, and high efficiency, with higher requirements for the power density, efficiency level, and heat dissipation capacity of the motors.

[0003] Compared with conventional stranded wire windings, flat wire windings have a higher slot fill factor, higher power density, and better heat dissipation capacity, so they are gradually used in the field of vehicle drive motors. Compared with stranded wire winding motors, flat wire winding motors have fewer turns per slot, usually with 4, 6, or 8 conductors. To facilitate the adjustment of the number of series turns per phase, multiple parallel branches generally exist.

[0004] To increase the selectivity of the number of series turns per phase, Chinese Patent No. CN104124803B discloses a bar-wound stator winding arrangement with long pitch and short pitch coils. As shown, 6 layers of conductors are divided into 3 sets of windings to form 3 parallel sub-windings. However, each parallel branch is only connected between adjacent layers (two layers), and there is a large current imbalance among the 3 branches, thus introducing a large circulating current additional loss and reducing the efficiency during high-speed operation. Figure 2 As shown, 6 layers of conductors are divided into 3 sets of windings to form 3 parallel sub-windings. However, each parallel branch is only connected between adjacent layers (two layers), and there is a large current imbalance among the 3 branches, thus introducing a large circulating current additional loss and reducing the efficiency during high-speed operation.

[0005] To address the above problems, Chinese Patent No. CN106026435A discloses an electrical device and a stator assembly for the electrical device. It is a 6-layer conductor 3-branch parallel connection, where 2 branches use coils in layers 1, 2 and layers 5, 6 in series, and the 3rd branch is the coil in layers 3, 4 in series. The current imbalance of the parallel branches is weakened, but there is still circulating current loss. At the same time, a complex busbar structure is added, which not only increases the end height but also correspondingly increases the cost.

[0006] Furthermore, Chinese Patent No. CN107546877A discloses a flat wire stator and motor with 6 layers per slot and 2-branch parallel connection. The main hairpin wires are distributed in layers 1 / 2, 3 / 4, and 5 / 6. However, due to the existence of cross-connecting hairpin wires in layers 2 / 3 and 4 / 5, and its lead wires are located on the crown side, the 2-branch lead wires are respectively located on the outermost layer and the innermost layer, and both the lead wires and the neutral wire are special-shaped wires, resulting in complex structure forming, a large number of molds required during actual production, and increased equipment investment cost during mass production. Summary of the Invention

[0007] To solve the defect of complex forming of the stator assembly structure in the above-mentioned prior art, the present invention proposes a flat wire stator assembly. The technical solution adopted by the present invention is a flat wire stator assembly, which is characterized by comprising: a stator core and at least one stator winding;

[0008] A plurality of mounting grooves are circumferentially formed on the inner wall of the stator core, and hairpin coils are inserted into the mounting grooves. The conductors in the grooves of the hairpin coils in the same mounting groove are arranged in L layers in sequence in an L-shaped manner. All the hairpin coils are divided into a first hairpin coil group, a second hairpin coil group, and a third hairpin coil group according to the positions of their straight-line segments in their respective mounting grooves. The two straight-line segments of the hairpin coils in the first hairpin coil group are both located at the positions of the hairpin coils in the first layer of the corresponding mounting grooves. The two straight-line segments of the hairpin coils in the second hairpin coil group are respectively evenly distributed at the positions of the hairpin coils in the Tth, (T + 1)th,..., (L - 1)th layers of a pair of mounting grooves, where L is an even number greater than or equal to 2, and T is an even number less than L. The two straight-line segments of the hairpin coils in the third hairpin coil group are both located at the positions of the hairpin coils in the Lth layer of the corresponding mounting grooves;

[0009] The stator winding includes M parallel sub-windings formed by connecting hairpin coils distributed in different mounting grooves in series, and each sub-winding is formed by connecting some or all of the hairpin coils in each of the first hairpin coil group, the second hairpin coil group, and the third hairpin coil group in series;

[0010] Leads are provided on each sub-winding. The leads are located on the welding side of the stator core, and the leads are all connected to the first layer and the second layer, or the (L - 1)th and Lth layers of the mounting grooves.

[0011] Preferably, the number of slots of the stator core is Z, and the number of stator magnetic poles is 2p. The crown side span of the hairpin coils in the first hairpin coil group is Z / (2p). The crown side spans of the hairpin coils in the third hairpin coil group include Z / (2p) + 1 and Z / (2p) - 1. The crown side span of the hairpin coils in the second hairpin coil group is one of Z / (2p) + 1, Z / (2p), and Z / (2p) - 1.

[0012] Preferably, the number of slots of the stator core is Z, and the number of stator magnetic poles is 2p. The crown side span of the hairpin coils in the third hairpin coil group is Z / (2p). The crown side spans of the hairpin coils in the first hairpin coil group include Z / (2p) + 1 and Z / (2p) - 1. The crown side span of the hairpin coils in the second hairpin coil group is one of Z / (2p) + 1, Z / (2p), and Z / (2p) - 1.

[0013] Preferably, the number of mounting grooves corresponding to one stator pole in one phase is q, where q is an even number greater than or equal to 2. The first hairpin coil group includes q*p hairpin coils, the second hairpin coil group includes q*p*(L - 2) hairpin coils, and the third hairpin coil group includes q*p hairpin coils.

[0014] Preferably, the sub-winding is composed of p*L hairpin coils connected in series, and all of them include p hairpin coils of the first hairpin coil group, p*(L - 2) hairpin coils of the second hairpin coil group, and p hairpin coils of the third coil group.

[0015] Preferably, the first hairpin coil group includes the first coils with the same number and a crown side span of Z / (2p) + 1 and the second coils with a crown side span of Z / (2p) - 1. The first coils are sleeved outside the second coils to form a first coil pair arranged on the stator core. Adjacent two first coil pairs in each phase are arranged with an interval of Z / p mounting grooves, and the first hairpin coil group in each phase is adjacent to Z / m / p mounting grooves;

[0016] The second hairpin coil group has a unique hairpin coil span. Taking two hairpin coils with an interval of one mounting groove as the second coil pair, they are arranged on the stator core. Adjacent two second coil pairs in each phase are arranged with an interval of Z / 2 / p mounting grooves, and the second hairpin coil group in each phase is adjacent to Z / m / p mounting grooves;

[0017] The third hairpin coil group has a unique hairpin coil span. Taking two hairpin coils in two adjacent mounting grooves as the third coil pair, they are arranged on the stator core. Adjacent two third coil pairs in each phase are arranged with an interval of Z / p mounting grooves, and the third hairpin coil group in each phase is adjacent to Z / p mounting grooves.

[0018] Preferably, the lead-out wires of each phase sub-winding are connected in a Y shape or a Δ shape.

[0019] Preferably, the number M of the sub-windings is equal to the number q of mounting grooves corresponding to one stator pole in one phase, where q is an even number greater than or equal to 2. The number of phases of the motor is m, and q = Z / (2mp).

[0020] Preferably, after all the hairpin coils are inserted into the mounting grooves, a crown side is formed at one end of the stator core, and a welding side is formed at the opposite end. Among all the hairpin coils at the welding side end, those in the odd layers of the mounting grooves are twisted in one direction, and those in the even layers of the hairpin coils are twisted in the other direction, and the ends of the hairpin coils between different layers are welded in sequence to achieve electrical connection.

[0021] The present invention also provides a motor, including the above-mentioned flat wire stator assembly and rotor assembly.

[0022] Compared with the prior art, the present invention will have the following beneficial effects:

[0023] 1. Each hairpin coil in each parallel sub-winding of each phase is evenly distributed at different layers in each pole mounting groove, so that the back electromotive force and current of each parallel sub-winding are exactly the same, eliminating the additional copper loss of the stator winding circulating current caused by the parallel connection of the sub-windings, thereby improving the high-speed efficiency of the motor, ensuring the temperature uniformity of the stator winding, and further improving the motor life;

[0024] 2. The lead-out wires at the head and tail positions of each parallel sub-winding are located at adjacent positions, greatly simplifying the complexity of the Busbar, improving its reliability, reducing the amount of neutral copper bars, eliminating the injection molding material, reducing the end height, and thus reducing the material cost and manufacturing cost of the entire stator assembly;

[0025] 3. The types of hairpin coil wire shapes on the crown side are greatly reduced. At the same time, since the lead-out wires are located on the welding side, there are no special-shaped Ipin wires and special-shaped neutral wires, and the overall structure is relatively simple; if mold forming is used, the number of hairpin coil forming molds and the number of forming equipment are reduced, and if robotic bending is used, the number of bending machines is reduced, ultimately reducing the input cost of manufacturing equipment;

[0026] 4. The hairpin coils of each layer are independent of each other, without additional cross-layer hairpin wires, so that fully automated wire insertion can be achieved through independent wire cups, simplifying the manufacturing process and facilitating mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The present invention will be described in detail below in conjunction with the embodiments and the drawings, where:

[0028] Figure 1 is a schematic structural diagram of the stator assembly in Embodiment 1;

[0029] Figure 2 is a connection diagram of three parallel sub-windings;

[0030] Figure 3 is a schematic cross-sectional view of the motor stator and rotor;

[0031] Figure 4 is a schematic cross-sectional view of the hairpin coil;

[0032] Figure 5 is a schematic diagram of the mounting groove and the conductors in the groove;

[0033] Figure 6 is a schematic structural diagram of the hairpin coils of the first hairpin coil group in Embodiment 1;

[0034] Figure 7 is a schematic structural diagram of the first hairpin coil group;

[0035] Figure 8It is a schematic diagram of the hairpin coil structure of the second hairpin coil group;

[0036] Figure 9 It is a schematic diagram of the structure of the second hairpin coil group;

[0037] Figure 10 It is a schematic diagram of the hairpin coil structure of the third hairpin coil group;

[0038] Figure 11 It is a schematic diagram of the structure of the third hairpin coil group;

[0039] Figure 12 It is a schematic diagram of the structure of the first parallel sub-winding unit of the U phase;

[0040] Figure 13 It is a schematic diagram of the three-phase winding connection;

[0041] Figure 14 It is a schematic diagram of the arrangement of the hairpin coils in the installation slots of each stator winding of the three phases in Embodiment 1;

[0042] Figure 15 It is a schematic diagram of the electrical connection of the three-phase lead wires;

[0043] Figure 16 It is a schematic diagram of the hairpin coil structure of the first hairpin coil group in Embodiment 2;

[0044] Figure 17 It is a schematic diagram of the arrangement of the hairpin coils in the installation slots of each stator winding of the three phases in Embodiment 3.

[0045] 2. Stator core; 3. Welding side; 4. Lead wire; 5. Neutral copper bar; 6. Insulating paper; 7. Crown side; Stator assembly C1; Rotor assembly C2; Conductor A1; Insulating layer A2; First hairpin coil group T1; Second hairpin coil group T2; Third hairpin coil group T3; First coil T11; Second coil T12; First parallel sub-winding P1 of the U phase. Detailed implementation manners

[0046] A flat wire stator assembly includes a stator core 2 and at least one stator winding. As Figure 1 shown, Z installation slots are circumferentially formed on the inner wall of the stator core 2, hairpin coils are inserted into the installation slots, and a plurality of the hairpin coils in the same installation slot are sequentially inserted and arranged in L layers (L is an even number greater than or equal to 2). All the hairpin coils are divided into a first hairpin coil group T1, a second hairpin coil group T2, and a third hairpin coil group T3 according to their positions in the installation slots; as Figure 2 and 3 shown, the stator winding includes M sub-windings, and each sub-winding is composed of some or all of the hairpin coils in each of the first hairpin coil group T1, the second hairpin coil group T2, and the third hairpin coil group T3 connected in series.

[0047] The installation grooves are all through rectangular grooves, and insulating paper 6 is arranged in each rectangular groove to ensure the electrical insulation between the hairpin coils and the stator core 2. The hairpin coils are made of flat wires. As Figure 4 shown, its cross-section is a rectangular conductor A1 and an insulating layer A2 coated outside the conductor A1.

[0048] For the hairpin coils in the first hairpin coil group T1, the two straight-line segments are located in the first layer of a pair of installation grooves. For the hairpin coils in the second hairpin coil group T2, the two straight-line segments are respectively evenly distributed in the Tth, (T + 1)th,..., (L - 1)th layers of a pair of installation grooves, where L is an even number ≥ 2 and T is an even number < L. For the hairpin coils in the third hairpin coil group T3, the two straight-line segments are located in the Lth layer of a pair of installation grooves. The sub-windings are composed of a plurality of hairpin coils distributed in different installation grooves, different magnetic poles, and different layers in series.

[0049] By evenly distributing the hairpin coils in which the parallel sub-windings in each phase stator winding are connected in series in different layers and different poles of the stator slots, the above stator assembly ensures that the back electromotive forces of the parallel sub-windings are exactly the same, completely eliminates the circulating current between the parallel sub-windings, thereby reducing the additional copper loss of the circulating current during high-speed operation, and ensuring the temperature rise uniformity of the inner and outer layers of the stator winding.

[0050] For the sake of convenience of description, the above stator assembly is applied to an m-phase motor. The number of installation grooves opened in the stator core 2 is Z, the number of stator magnetic poles is 2p (p is a positive integer), the hairpin coils are wound in L layers (L is an even number greater than or equal to 2) in the installation grooves, the number of slots per pole per phase q (q is an even number greater than or equal to 2), and the number of parallel sub-windings M = q. In this embodiment, m = 3, Z = 48, p = 4, L = 4, q = Z / (2mp) = 2, and M = q = 2.

[0051] As Figure 5 shown, when the three-phase stator winding is wound into 4 layers in the installation grooves of the stator core 2, that is, there are 4 conductors in each installation groove of the stator core 2, which are sequentially recorded as the first layer L1, the second layer L2, the third layer L3, and the fourth layer L4 from the outside to the inside along the radial direction of the motor. Each phase of the first hairpin coil group T1 includes q*p = 8 hairpin coils, each phase of the second hairpin coil group T2 includes q*p*(L - 2) = 16 hairpin coils, and each phase of the third hairpin coil group T3 includes q*p = 8 hairpin coils. And this flat wire stator assembly altogether includes three stator windings, each stator winding corresponds to one phase and is composed of 2 parallel sub-windings. In each phase, the parallel sub-windings are composed of p*L = 16 coils connected in series, and all include 4 hairpin coils of the first hairpin coil group T1, 8 hairpin coils of the second hairpin coil group T2, and 4 hairpin coils of the third coil group.

[0052] Specifically, the hairpin coils of the first hairpin coil group T1 are full pitch coils with a crown side 7-span of Z / (2p) = 6. The hairpin coils of the third hairpin coil group T3 include two types: long span coils with a crown side 7-span of Z / (2p)+1 = 7 and short span coils with a crown side 7-span of Z / (2p)-1 = 5. The hairpin coils of the second hairpin coil group T2 can be any one of those with a crown side 7-span of Z / (2p)+1 = 7, Z / (2p) = 6, or Z / (2p)-1 = 5. Of course, there are various different combinations of the hairpin coils in the sub-windings. In another embodiment, the hairpin coils of the third hairpin coil group T3 can be full pitch coils with a crown side 7-span of Z / (2p) = 6, the hairpin coils of the first hairpin coil group T1 can include two types: long span coils with a crown side 7-span of Z / (2p)+1 = 7 and short span coils with a crown side 7-span of Z / (2p)-1 = 5, and the hairpin coils of the second hairpin coil group T2 can be any one of those with a crown side 7-span of Z / (2p)+1 = 7, Z / (2p) = 6, or Z / (2p)-1 = 5.

[0053] In this embodiment, as Figure 6 and 7 shown, the first hairpin coil group T1 includes 12 first coils T11 with a crown side 7-span of Z / (2p)+1 = 7 and 12 second coils T12 with a crown side 7-span of Z / (2p)-1 = 5, both having the same quantity and being distributed in three phases. Therefore, each phase contains 4 first coils T11 and 4 second coils T12. The first coil T11 and the second coil T12 have similar structures, with the only difference being the span. Taking the first coil T11 as an example, it includes bending parts B10 and B14, straight segment parts B11 and B13 inserted into the installation slots, and a connecting part B12 between the two straight segments, presenting a U shape as a whole. The straight segment parts B11 and B13 are respectively located in the same layer within the installation slots and are in the first layer.

[0054] The straight segment parts B11 and B13 of the first coil T11 are inserted into the installation slots from one axial side of the stator core 2 and bent in the same direction on the other axial side of the stator core 2, thereby forming the bending parts B10 and B14. The number of stator slots spanned by the connecting part B12 between the straight segment parts B11 and B13 forms the crown side 7-span, and one end of the stator core 2 close to the bending part is the welding side 3, and the other end is the crown side 7. Of course, the first hairpin coil group T1 can also include three types of hairpin coils with crown side 7-spans of 5, 6, and 7 respectively.

[0055] The first coil T11 is sleeved outside the second coil T12 to form pairs of the first coils T11 arranged on the stator core 2. For each phase, two adjacent pairs of the first coils T11 are arranged with an interval of Z / p = 12 mounting slots. The first hairpin coil groups T1 of each phase are adjacent to Z / m / p = 4 mounting slots, that is, the stator windings of the U phase, V phase, and W phase are respectively offset by 4 mounting slots.

[0056] As Figure 8 and 9 shown, a single hairpin coil of the second hairpin coil group T2 includes bent portions B10 and B14, straight segment portions B11 and B13 inserted into the mounting slots, and a connecting portion B12 between the two straight segments, presenting a U shape as a whole. The straight segment portions B11 and B13 of the coils of the second hairpin coil group T2 are inserted into the mounting slots from one axial side of the stator core 2 and bent in the opposite direction on the other axial side of the stator core 2, thereby forming the bent portions B10 and B14. The straight segment portions B11 and B13 are respectively located in layers L2 and L3 (L = 4, T = 2) in the mounting slots. The crown side span formed by the connecting portion B12 between the straight segment portions B11 and B13 is one of 5, 6, and 7. In this embodiment, 6 is taken.

[0057] The three-phase second hairpin coil group T2 is composed of 48 (m*q*p*(L - 2) = 48) hairpin coils, corresponding to 16 (q*p*(L - 2) = 16) hairpin coils for each phase. Taking two hairpin coils with an interval of one mounting slot as pairs of the second coils T12, they are arranged on the stator core 2. For each phase, two adjacent pairs of the second coils T12 are arranged with an interval of Z / 2 / p = 6 mounting slots. The second hairpin coil groups T2 of each phase are adjacent to Z / m / p = 4 mounting slots, that is, the stator windings of the U phase, V phase, and W phase are respectively offset by 4 mounting slots.

[0058] As Figure 10 and 11 shown, a single coil of the third hairpin coil group T3 includes bent portions B10 and B14, straight segment portions B11 and B13 inserted into the mounting slots, and a connecting portion B12 between the two straight segments, presenting a U shape as a whole. The straight segment portions B11 and B13 of the coils of the third hairpin coil group T3 are inserted into the mounting slots from one axial side of the stator core 2 and bent in the same direction on the other axial side of the stator core 2, thereby forming the bent portions B10 and B14. The crown side span formed by the connecting portion B12 between the straight segment portions B11 and B13 is a full pitch of 6.

[0059] The three-phase third hairpin coil group T3 consists of 24 hairpin coils, with 8 hairpin coils corresponding to each phase, and two hairpin coils in two adjacent mounting slots are arranged as the third coil pair on the stator core 2. For each phase, the adjacent two third coil pairs are arranged with an interval of Z / p = 12 mounting slots. The third hairpin coil group T3 of each phase is adjacent to Z / p = 4 mounting slots, that is, the stator windings of the U-phase, V-phase, and W-phase are respectively 4 mounting slots apart.

[0060] Since the stator windings of each phase are the same, only the arrangement in the mounting slots is 4 slots different. Here, the U-phase is used to illustrate the composition of each parallel sub-winding. As Figure 12 shown, the first parallel sub-winding of the U-phase has a total of 16 coils, which are composed of 4 second coils T12 in the first hairpin coil group T1, 8 hairpin coils in the second hairpin coil group T2, and 4 hairpin coils in the third hairpin coil group T3 connected in series. The second parallel sub-winding of the U-phase has a total of 16 coils, which are composed of 4 first coils T11 in the first hairpin coil group T1, 8 hairpin coils in the second hairpin coil group T2, and 4 hairpin coils in the third hairpin coil group T3.

[0061] In addition, the first parallel sub-winding P1 of the U-phase can also be composed of 4 first coils T11 in the first hairpin coil group T1, 8 hairpin coils in the second hairpin coil group T2, and 4 hairpin coils in the third hairpin coil group T3. The second parallel sub-winding is composed of 4 second coils T12 in the first hairpin coil group T1, 8 hairpin coils in the second hairpin coil group T2, and 4 hairpin coils in the third hairpin coil group T3.

[0062] As described above, after the hairpin coils of each phase are inserted into the stator slots from one axial side of the stator core 2, they are bent and twisted on the other axial side of the stator core 2. The bending and twisting are carried out through a twisting die. The odd layers are twisted in one direction, and the even layers are twisted in the other direction to form the above-mentioned bent parts of the hairpin coils. The bent part of the first hairpin coil group T1 is electrically connected to the corresponding bent part of the second hairpin coil group T2 through welding. The bent part of the second hairpin coil group T2 is electrically connected to the corresponding bent part of the third hairpin coil group T3 through welding. The number of stator slots spanned by the two welded parts forms the welding side 3 span, and the welding side 3 span can be one of 5, 6, and 7. Welding can be carried out by methods such as TIG welding, plasma welding, and laser welding.

[0063] After welding, taking the sub-winding as the minimum unit for electrical connection, at this time, the head and tail lead-out wires 4 of each parallel sub-winding are located on the welding side 3 and are all located in the first and second layers, or the third and fourth layers. The lead-out wires 4 of the two parallel sub-windings in the same stator winding are combined into one. Therefore, the stator assembly of the three-phase motor has a total of three lead-out wires 4. As Figure 15 shown, these three lead-out wires 4 are connected into a Y shape or a Δ shape through a neutral copper bar 5.

[0064] Since the lead wires 4 of two adjacent sub-windings are combined into one, the last three lead wires 4 of the three-phase stator assembly are all located on the welding side 3 and can be directly connected to the terminals for extraction, thus greatly simplifying the Busbar complexity, improving its reliability, reducing the amount of neutral copper bar 5 at the same time, eliminating the injection molding material, reducing the end height, and further reducing the material cost and manufacturing cost of the entire stator assembly.

[0065] On the other hand, since the above hairpin coils need to be obtained by die stamping or realized by robot bending, although the die stamping method has high precision and high efficiency, it requires additional die opening, while the robot bending method has poor forming precision and relatively low efficiency, but has good flexibility.

[0066] In this solution, as Figure 13 and 14 shown, the stator winding is composed of 2 types of hairpin coils in the first hairpin coil group T1, 1 type of hairpin coil in the second hairpin coil group T2, and 1 type of hairpin coil in the third hairpin coil group T3, a total of 4 types of hairpin coils. The types of hairpin coils are greatly reduced. If the die forming method is adopted, the number of hairpin forming dies is reduced. For mass production, the investment in forming equipment or bending equipment can be reduced, and thus the production cost can be reduced. At the same time, the three hairpin coils of the first hairpin coil group T1, the second hairpin coil group T2, and the third hairpin coil group T3 are independent of each other, without additional cross-over wires, and full-automatic wire insertion can be realized through independent wire cups, greatly improving the mass production efficiency.

[0067] As the second embodiment of the present invention, another flat wire stator assembly is disclosed. As Figure 16 shown, the difference from the above embodiment is that the first hairpin coil group T1 includes hairpin coils with three spans on the crown side 7. The first hairpin coil group T1 is composed of 24 hairpin coils, including 6 first coils T11 of the first hairpin coil group T1, 6 second coils T12 of the first hairpin coil group T1, and 12 third coils of the first hairpin coil group T1. Among them, corresponding to each phase, that is, each phase includes 2 first coils T11 of the first hairpin coil group T1, 2 second coils T12 of the first hairpin coil group T1, and 4 third coils of the first hairpin coil group T1, and the span of the third coil is 6.

[0068] The three-phase second hairpin coil group T2 is the same as that in the first embodiment. The span of the crown side 7 is one of 5, 6, and 7, and it is composed of 48 hairpin coils. Corresponding to each phase, that is, each phase contains 16 hairpin coils of the second hairpin coil group T2; the three-phase third hairpin coil group T3 is the same as that in the first embodiment. The span of the crown side 7 is 6, and it is composed of 24 hairpin coils. Corresponding to each phase, that is, each phase contains 8 hairpin coils of the third hairpin coil group T3.

[0069] As the third embodiment of the present invention, another flat wire stator assembly is disclosed. As Figure 17 shown, the difference from the first embodiment is that the hairpin coils are arranged in the slots as Figure 17 shown, where L = 8, that is, 8 layers of flat wire conductors are arranged in the slots. The two straight sections of the hairpin coils in the first hairpin coil group T1 are located in the same layer and in the first layer. The two straight sections of the hairpin coils in the second hairpin coil group T2 are located in the 2nd and 3rd layers, 4th and 5th layers, and 6th and 7th layers respectively. The two straight sections of the hairpin coils in the third hairpin coil group T3 are located in the same layer and in the 8th layer. The three-phase first hairpin coil group T1 is composed of 24 hairpin coils, including 12 first coils T11 of the first hairpin coil group T1 and 12 second coils T12 of the first hairpin coil group T1. The three-phase second hairpin coil group T2 is composed of 144 hairpin coils, including 48 hairpin coils located in the 2nd and 3rd layers, 48 hairpin coils located in the 4th and 5th layers, and 48 hairpin coils located in the 6th and 7th layers. The three-phase third hairpin coil group T3 is composed of 24 hairpin coils.

[0070] It can be seen from the first and third embodiments that when the number of layers of hairpin coils installed in the slots is 4, the stator winding is composed of 2 types of hairpin coils in the first hairpin coil, 1 type of hairpin coil in the second hairpin coil group T2, and 1 type of hairpin coil in the third hairpin coil group T3, including a total of 4 different types of hairpin coils. When the number of layers of hairpin coils installed in the slots is 6, the stator winding is composed of 2 types of hairpin coils in the first hairpin coil, 2 types of hairpin coils in the second hairpin coil group T2, and 1 type of hairpin coil in the third hairpin coil group T3, including a total of 5 different types of hairpin coils. When the number of layers of hairpin coils installed in the slots is 8, the stator winding is composed of 2 types of hairpin coils in the first hairpin coil, 3 types of hairpin coils in the second hairpin coil group T2, and 1 type of hairpin coil in the third hairpin coil group T3, including a total of 6 different types of hairpin coils. Therefore, from the above statistics, by adopting the technical solution of the present invention, the types of hairpin coils are greatly reduced, and the mold bending forming and batch processing efficiency are greatly improved.

[0071] The present invention also discloses a motor, as Figure 3 shown. This motor can be applied to automotive drive, and this motor includes a rotor assembly C2 and the stator assembly C1 as described above.

[0072] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A flat wire stator assembly, characterized in that, comprising: a stator core and at least one stator winding; A plurality of mounting grooves are circumferentially formed on the inner wall of the stator core, and hairpin coils are inserted into the mounting grooves. The conductors in the grooves of the hairpin coils in the same mounting groove are sequentially inserted and arranged in L layers. All the hairpin coils are divided into a first hairpin coil group, a second hairpin coil group, and a third hairpin coil group according to the positions of their straight-line parts in their respective mounting grooves. The two straight-line parts of the hairpin coils in the first hairpin coil group are both located at the positions where the first-layer hairpin coils of the corresponding mounting grooves are located. The two straight-line parts of the hairpin coils in the second hairpin coil group are respectively evenly distributed at the positions where the hairpin coils of the Tth, (T + 1)th,..., (L - 1)th layers of a pair of mounting grooves are located. L is an even number greater than or equal to 2, and T is an even number less than L. The two straight-line parts of the hairpin coils in the third hairpin coil group are both located at the positions where the Lth-layer hairpin coils of the corresponding mounting grooves are located; The stator winding includes M parallel sub-windings formed by series-connected hairpin coils distributed in different mounting grooves, and each sub-winding is formed by series-connecting some or all of the hairpin coils in each of the first hairpin coil group, the second hairpin coil group, and the third hairpin coil group; Each sub-winding is provided with a lead wire. The lead wire is located on the welding side of the stator core, and the lead wires are all connected to the first layer and the second layer, or the (L - 1)th and Lth layers of the mounting grooves; The number of mounting grooves of the stator core is Z, and the number of stator magnetic poles is 2p. The crown side span of the hairpin coils in the third hairpin coil group is Z / (2p). The crown side spans of the hairpin coils in the first hairpin coil group include Z / (2p) + 1 and Z / (2p) - 1. The crown side span of the hairpin coils in the second hairpin coil group is one of Z / (2p) + 1, Z / (2p), and Z / (2p) - 1; or the number of mounting grooves of the stator core is Z, and the number of stator magnetic poles is 2p. The crown side span of the hairpin coils in the first hairpin coil group is Z / (2p). The crown side spans of the hairpin coils in the third hairpin coil group include Z / (2p) + 1 and Z / (2p) - 1. The crown side span of the hairpin coils in the second hairpin coil group is one of Z / (2p) + 1, Z / (2p), and Z / (2p) - 1; The first hairpin coil group includes a first coil with a crown side span of Z / (2p) + 1 and a second coil with a crown side span of Z / (2p) - 1, and the number of the first coil and the second coil is the same. The first coil is sleeved outside the second coil to form a first coil pair and is arranged on the stator core. Each adjacent two first coil pairs in each phase are arranged at an interval of Z / p mounting grooves, and the adjacent first hairpin coil groups in each phase are arranged at an interval of Z / m / p mounting grooves; The hairpin coils included in the second hairpin coil group have a unique span. The hairpin coils in adjacent two mounting grooves are used as a second coil pair and are arranged on the stator core. Each adjacent two second coil pairs in each phase are arranged at an interval of Z / 2 / p mounting grooves, and the adjacent second hairpin coil groups in each phase are arranged at an interval of Z / m / p mounting grooves; The hairpin coil spans included in the third hairpin coil group are unique. Taking two hairpin coils in two adjacent mounting slots as a third coil pair, they are arranged on the stator core. For each phase, two adjacent third coil pairs are arranged with a spacing of Z / p mounting slots, and the third hairpin coil groups of each phase are adjacent with a spacing of Z / m / p mounting slots. The number M of the sub-windings is equal to the number q of mounting slots corresponding to one stator pole in one phase, q is an even number greater than or equal to 2, the number of phases of the motor is m, and q = Z / (2mp).

2. The flat wire stator assembly according to claim 1, characterized in that, the number of mounting slots corresponding to one stator pole in one phase is q, q is an even number greater than or equal to 2, the first hairpin coil group includes q*p hairpin coils, the second hairpin coil group includes q*p*(L - 2) hairpin coils, and the third hairpin coil group includes q*p hairpin coils.

3. The flat wire stator assembly according to claim 2, characterized in that, the sub-windings are composed of p*L hairpin coils connected in series, and each of them includes p hairpin coils of the first hairpin coil group, p*(L - 2) hairpin coils of the second hairpin coil group, and p hairpin coils of the third coil group.

4. The flat wire stator assembly according to claim 1, characterized in that, the lead-out wires of the sub-windings of each phase are connected in a Y shape or a Δ shape.

5. The flat wire stator assembly according to claim 4, characterized in that, after all the hairpin coils are inserted into the mounting slots, a crown side is formed at one end of the stator core, and a welding side is formed at the opposite end. Among all the hairpin coils at the welding side end, the straight segment parts in the odd layers of the mounting slots are twisted in one direction, and the hairpin coils in the even layers are twisted in the other direction, and the ends of the hairpin coils between different layers are welded in sequence to achieve electrical connection.

6. A motor, characterized in that, it includes the flat wire stator assembly according to any one of claims 1 - 5 and a rotor assembly.

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