Hairpin type flat wire motor winding

Abstract

The utility model discloses a hairpin type flat wire motor winding, which comprises stator windings arranged in stator slots of a stator core. 2K slot layers are formed on the stator winding, the stator winding comprises a plurality of flat wire coils, and each flat wire coil is in a hairpin shape and comprises two straight line sections, two pins and a connecting section; the pins extend outwards; each stator winding is provided with lap windings and concentric windings, and the lap windings and the concentric windings are alternately arranged; and two straight line segments of the flat wire coil are respectively inserted into the 2i slot layer and the 2i-1 slot layer. The utility model has the advantages of simple manufacturing process, high production efficiency and low manufacturing cost.

Description

Technical Field

[0001] The utility model relates to the technical field of new energy automobile motors, in particular to a hairpin-type flat wire motor winding. Background Art

[0002] Compared with the permanent magnet synchronous motor with multi-strand round enameled wire winding, the flat wire motor can significantly improve the slot fill rate of the motor, so it has the advantages of high motor efficiency, high power density, good temperature performance, etc. It can effectively reduce the effective volume of the motor, the height of the stator coil end, and effectively reduce the axial length of the motor. Therefore, more and more new energy vehicle drive systems tend to use flat wire motors.

[0003] In the design and manufacture of permanent magnet synchronous flat wire motors, there are different structural requirements and winding arrangements, which will have a direct impact on the process complexity of stator production. In the prior art, a single flat wire winding requires a variety of flat wires, the winding scheme is not easy to deform, the winding process is complex, the manufacturing equipment is expensive, and the manufacturing cost is high. Therefore, it is necessary to study a new flat wire winding form that can effectively reduce the number of coils and reduce the process complexity. Utility Model Content

[0004] The purpose of the utility model is to provide a hairpin-type flat wire motor winding. The utility model has the advantages of simple manufacturing process, high production efficiency and low manufacturing cost.

[0005] The technical solution of the utility model is as follows: a hairpin-type flat wire motor winding, comprising layers of stator windings arranged in each stator slot of a stator core; the stator winding forms 2K slot layers, wherein K is a positive integer greater than 1; each of the stator windings comprises a plurality of individual flat wire coils; the flat wire coils are in a hairpin-type, comprising two straight line segments inserted in the stator slots, two pins located at one end of the two straight line segments and a connecting segment connecting the other ends of the two straight line segments; the pins extend outward; the two straight line segments of each flat wire winding are respectively inserted into 2i and 2i-1 slot layers, the straight line segment inserted into the 2i slot layer is located on one side of the first direction of the straight line segment inserted into the 2i-1 slot layer, i is an integer not less than 1; the first direction is clockwise or counterclockwise.

[0006] In the aforementioned hairpin flat wire motor winding, each phase of the stator winding is provided with two mixed windings, namely, stacked windings and concentric windings, which are arranged alternately; the stacked windings are composed of full-pitch coils, and the concentric windings are composed of short-pitch windings and long-pitch windings; the short-pitch windings and long-pitch windings of the concentric windings are arranged alternately in the branches.

[0007] In the aforementioned hairpin-type flat wire motor winding, the number of stator slots opened in the stator core is 48, the number of motor poles is 8, and the stator winding includes three phases, including U phase, V phase and W phase. The winding method of the stator winding of each phase is the same. Each of the stator slots has 6 slot layers a, b, c, d, e, and f, and each phase of the stator winding includes two branches in parallel; the V phase and W phase are similar to the U phase, and the stacked windings and concentric windings are arranged alternately.

[0008] The hairpin flat wire motor winding includes a first part consisting of the first slot to the fourteenth slot, the first part is a lapped winding, and under the two poles, the span of the winding is Y;

[0009] The first branch of the first part of the winding route is,

[0010] Under the N pole, when i=1, the left straight line segment of the winding coil at the crown end is in the f layer of slot 1, the right straight line segment is in the e layer of the 7th slot, the span is 6, and the line layer is in the 1st and 2nd layers; the left straight line segment of the winding coil at the welding end is in the e layer of slot 2, the right straight line segment is in the f layer of slot 8, the span is 6, and the line layer is in the 1st and 2nd layers;

[0011] Under the S pole, when i=1, the left straight line segment of the winding coil at the crown end is in the f layer of slot 8, the right straight line segment is in the e layer of the 14th slot, the span is 6, and the line layer is in the 1st and 2nd layers; the left straight line segment of the winding coil at the welding end is in the e layer of slot 7, the right straight line segment is in the f layer of the 13th slot, the span is 6, and the line layer is in the 1st and 2nd layers;

[0012] The second branch of the first part has a winding route of

[0013] Under the N pole, when i=1, the left straight line segment of the winding coil at the crown end is in the f layer of slot 2, the right straight line segment is in the e layer of the 8th slot, the span is 6, and the line layer is in the 1st and 2nd layers; the left straight line segment of the winding coil at the welding end is in the e layer of slot 1, the right straight line segment is in the f layer of the 7th slot, the span is 6, and the line layer is in the 1st and 2nd layers;

[0014] Under the S pole, when i=1, the left straight line segment of the winding coil at the crown end is in the f layer of slot 7, the right straight line segment is in the e layer of the 13th slot, the span is 6, and the line layer is in the 1st and 2nd layers; the left straight line segment of the winding coil at the welding end is in the e layer of slot 8, the right straight line segment is in the f layer of the 14th slot, the span is 6, and the line layer is in the 1st and 2nd layers;

[0015] The stator winding forms a lap winding after the first branch and the second branch are connected in parallel.

[0016] The hairpin flat wire motor winding includes a second part consisting of the 13th slot to the 26th slot, the second part is a concentric winding, and the spans of the stator winding under each pole are Y+1 and Y-1 respectively;

[0017] The winding span of the crown end of the first branch of the second part is Y+1, and the winding route is,

[0018] Under the N pole, when i=1, the left straight line segment of the crown winding coil is in the f layer of slot 13, and the right straight line segment is in the e layer of slot 20, with a span of 7; the left straight line segment of the winding coil at the welding end is in the e layer of slot 14, and the right straight line segment is in the f layer of slot 19, with a span of 5;

[0019] Under the S pole, when i=1, the left straight line segment of the crown winding coil is in the f layer of slot 19, and the right straight line segment is in the e layer of slot 26, with a span of 7; the left straight line segment of the winding coil at the welding end is in the e layer of slot 20, and the right straight line segment is in the f layer of slot 25, with a span of 5;

[0020] The winding span of the crown end of the second branch of the second part is Y-1, and the winding route is,

[0021] Under the N pole, when i=1, the left straight line segment of the crown winding coil is in the f layer of slot 14, and the right straight line segment is in the e layer of slot 19, with a span of 5; the left straight line segment of the welding end winding coil is in the e layer of slot 13, and the right straight line segment is in the f layer of slot 20, with a span of 7;

[0022] Under the S pole, when i=1, the left straight line segment of the crown winding coil is in the f layer of slot 20, and the right straight line segment is in the e layer of slot 25, with a span of 5; the left straight line segment of the winding coil at the welding end is in the e layer of slot 19, and the right straight line segment is in the f layer of slot 26, with a span of 7;

[0023] After the stator winding is connected in parallel in the first branch and the second branch, between the 13th slot and the 26th slot, the spans under the same pole are 5 and 7, both of which constitute concentric windings. The winding coils of the two connected slots form a concentric winding, and the winding with a span of 7 wraps the winding with a span of 5.

[0024] In the aforementioned hairpin flat wire motor winding, the U-phase winding is alternately arranged by lap winding and concentric winding to form a complete winding of one phase;

[0025] The winding sequence of the first branch of phase U is:

[0026] 1f-7e-13f-20e-25f-31e-38f-43e-1d-7c-13d-20c-25d-31c-38d-43c-1b-7a-13b-20a-25b-31a-38b-43a-37a-32b-26a-19b-14a-8b-2a-44b-37c-32d-26c-19d-14c-8d-2c-44d-37e-32f-26e-19f-14e-8f-2e-44f, among which 1f-7e is a winding coil connected to the crown end, and the heads and tails of the two connected coils are welded together, that is, 7e and 13f are welded together;

[0027] The winding sequence of the second branch of phase U is:

[0028] 2f-8e-14f-19e-26f-32e-37f-44e-2d-8c-14d-19c-26d-32c-37d-44c-2b-8a-14b-19a-26b-32a-37b-44a-38a-31b-25a-20b-13a-7b-1a-43b-38c-31d-25c-20d-13c-7d-1c-43d-38e-31f-25e-20f-13e-7f-1e-43f, among which 2f-8e is a winding coil connected to the crown end, and the heads and tails of the two connected coils are welded together, that is, 8e and 14f are welded together.

[0029] Compared with the prior art, the flat wire coil motor implemented according to the present application has a greatly reduced manufacturing process difficulty, and only three specifications of each phase winding are required, which effectively improves production efficiency; and it can undergo a variety of different deformations to meet different needs, greatly reducing manufacturing costs.

[0030] Therefore, the present application has the advantages of simple manufacturing process, high production efficiency and low manufacturing cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the conductor distribution diagram in the slots of a 48-slot 8-pole hairpin flat wire coil in an embodiment of the utility model;

[0032] Figure 2 This is a winding arrangement diagram of a single-phase winding of a 48-slot 8-pole hairpin flat wire stator in an embodiment of the utility model;

[0033] Figure 3 This is a layout diagram of the lapped windings in the 48-slot 8-pole hairpin flat wire stator winding in the embodiment of the utility model;

[0034] Figure 4 It is a schematic diagram of the concentric winding in the 48-slot 8-pole hairpin flat wire stator winding in the embodiment of the utility model;

[0035] Figure 5 It is a structural schematic diagram of a single coil of the utility model.

[0036] The markings in the attached figure are: 1-straight line segment, 2-connecting segment, 3-pin. DETAILED DESCRIPTION

[0037] The present invention is further described below in conjunction with the accompanying drawings and embodiments, but they are not intended to limit the present invention.

[0038] Embodiment. A hairpin-type flat wire motor winding has higher torque density, power density and motor efficiency, including layers of stator windings placed in slots of a stator core, the stator windings forming 2K slot layers; a plurality of stator slots arranged along the circumference of the stator core are provided on the stator core, and after the stator windings are arranged, each stator slot has 2K slot layers arranged along the radial direction of the stator core, wherein K is a positive integer greater than 1, that is, the stator slots can accommodate an even number of conductor layers not less than 4, such as 4, 6, 8, 10, etc.

[0039] The stator winding consists of several Figure 5 The single flat wire coil shown is in the shape of a hairpin, and includes two straight segments 1 inserted into the stator slots, two pins 3 respectively located at one end of the two straight segments 1, and a connecting segment 2 connecting the other ends of the two straight segments 1. The two pins 3 of the flat wire coil extend outwards respectively, so that two adjacent flat wire coils on the same branch can be connected in series by welding.

[0040] Since the two pins 3 of each flat wire coil on the stator winding extend outward respectively, the clockwise pin 3 of any flat wire coil in the stator winding is connected to the counterclockwise pin 3 of the flat wire coil located at the corresponding span on the clockwise side of the flat wire coil, and the counterclockwise pin 3 is connected to the clockwise pin 3 of the flat wire coil located at the corresponding span on the counterclockwise side of the flat wire coil, that is, the coils under different poles are connected together.

[0041] At one end of the stator core, the straight segments 1 of each flat wire are inserted into the stator slots along the axial slot direction, and the straight segments 1 of each flat wire are respectively inserted into the 2i and 2i-1 slot layers, and the straight segment 1 inserted into the 2i slot layer is located on one side of the first direction of the straight segment 1 inserted into the 2i-1 slot layer, that is, the two straight segments 1 of a flat wire are respectively inserted into the 2nd slot layer and the 1st slot layer, the 4th slot layer and the 3rd slot layer, the 6th slot layer and the 5th slot layer, or the 8th slot layer and the 7th slot layer; wherein the first direction can be clockwise or counterclockwise, and the flat wires are inserted into the stator slots in sequence along the same direction.

[0042] The number of stator slots opened in the stator core is 48, the number of motor poles is 8, the stator winding includes three phases, including U phase, V phase and W phase, and the winding method of each phase winding is the same. Each stator slot has 6 slot layers a, b, c, d, e, and f, and each phase winding includes two branches in parallel.

[0043] like Figure 3 , including the first part consisting of the 1st slot to the 14th slot, the first part is a lapped winding, under these two poles, the span of the winding is Y; the dotted line part is the crown end, and the solid line part is the welding end;

[0044] like Figure 3 , the first branch of the first part of the winding route is,

[0045] Under the N pole, when i=1, the left straight line segment 1 of the winding coil at the crown end is in the f layer of slot 1, the right straight line segment 1 is in the e layer of the 7th slot, the span is 6, and the line layer is in the 1st and 2nd layers; the left straight line segment 1 of the winding coil at the welding end is in the e layer of slot 2, the right straight line segment 1 is in the f layer of the 8th slot, the span is 6, and the line layer is in the 1st and 2nd layers;

[0046] Under the S pole, when i=1, the left straight line segment 1 of the winding coil at the crown end is in the f layer of slot 8, the right straight line segment 1 is in the e layer of the 14th slot, the span is 6, and the line layer is in the 1st and 2nd layers; the left straight line segment 1 of the winding coil at the welding end is in the e layer of slot 7, the right straight line segment 1 is in the f layer of the 13th slot, the span is 6, and the line layer is in the 1st and 2nd layers;

[0047] like Figure 3 , the second branch of the first part has a winding route of,

[0048] Under the N pole, when i=1, the left straight line segment 1 of the winding coil at the crown end is in the f layer of slot 2, the right straight line segment 1 is in the e layer of the 8th slot, the span is 6, and the line layer is in the 1st and 2nd layers; the left straight line segment 1 of the winding coil at the welding end is in the e layer of slot 1, the right straight line segment 1 is in the f layer of the 7th slot, the span is 6, and the line layer is in the 1st and 2nd layers;

[0049] Under the S pole, when i=1, the left straight line segment 1 of the winding coil at the crown end is in the f layer of slot 7, the right straight line segment 1 is in the e layer of the 13th slot, the span is 6, and the line layer is in the 1st and 2nd layers; the left straight line segment 1 of the winding coil at the welding end is in the e layer of slot 8, the right straight line segment 1 is in the f layer of the 14th slot, the span is 6, and the line layer is in the 1st and 2nd layers;

[0050] like Figure 3 , the stator winding forms a stacked winding after the first branch and the second branch are connected in parallel.

[0051] like Figure 4, including a second part consisting of the 13th slot to the 26th slot, the second part is a concentric winding, and the spans of the stator winding under each pole are Y+1 and Y-1 respectively; wherein the dotted line part is the crown end, and the solid line part is the welding end;

[0052] like Figure 4 and Figure 1 ,, the winding span of the crown end of the first branch of the second part is Y+1, and the winding route is,

[0053] Under the N pole, when i=1, the left straight line segment 1 of the crown winding coil is in the f layer of slot 13, and the right straight line segment 1 is in the e layer of slot 20, with a span of 7; the left straight line segment 1 of the welding end winding coil is in the e layer of slot 14, and the right straight line segment 1 is in the f layer of slot 19, with a span of 5;

[0054] Under the S pole, when i=1, the left straight line segment 1 of the crown winding coil is in the f layer of slot 19, and the right straight line segment 1 is in the e layer of slot 26, with a span of 7; the left straight line segment 1 of the welding end winding coil is in the e layer of slot 20, and the right straight line segment 1 is in the f layer of slot 25, with a span of 5;

[0055] like Figure 4 and Figure 1 , the winding span of the crown end of the second branch of the second part is Y-1, and the winding route is,

[0056] Under the N pole, when i=1, the left straight line segment 1 of the crown winding coil is in the f layer of slot 14, and the right straight line segment 1 is in the e layer of slot 19, with a span of 5; the left straight line segment 1 of the welding end winding coil is in the e layer of slot 13, and the right straight line segment 1 is in the f layer of slot 20, with a span of 7;

[0057] Under the S pole, when i=1, the left straight line segment 1 of the crown winding coil is in the f layer of slot 20, and the right straight line segment 1 is in the e layer of slot 25, with a span of 5; the left straight line segment 1 of the welding end winding coil is in the e layer of slot 19, and the right straight line segment 1 is in the f layer of slot 26, with a span of 7;

[0058] like Figure 4 and 1 As shown, after the stator winding is connected in parallel in the first branch and the second branch, between the 13th slot and the 26th slot, the spans under the same pole are 5 and 7, both of which constitute concentric windings. The winding coils of the two connected slots form a concentric winding, and the winding with a span of 7 wraps the winding with a span of 5.

[0059] Combination Figure 1 and Figure 2 The U-phase winding is alternately arranged by stacking windings and concentric windings to form a complete winding of one phase;

[0060] The winding sequence of the first branch of phase U is:

[0061] 1f-7e-13f-20e-25f-31e-38f-43e-1d-7c-13d-20c-25d-31c-38d-43c-1b-7a-13b-20a-25b-31a-38b-43a-37a-32b-26a-19b-14a-8b-2a-44b-37c-32d-26c-19d-14c-8d-2c-44d-37e-32f-26e-19f-14e-8f-2e-44f, among which 1f-7e is a winding coil connected to the crown end, and the heads and tails of the two connected coils are welded together, that is, 7e and 13f are welded together;

[0062] The winding sequence of the second branch of phase U is:

[0063] 2f-8e-14f-19e-26f-32e-37f-44e-2d-8c-14d-19c-26d-32c-37d-44c-2b-8a-14b-19a-26b-32a-37b-44a-38a-31b-25a-20b-13a-7b-1a-43b-38c-31d-25c-20d-13c-7d-1c-43d-38e-31f-25e-20f-13e-7f-1e-43f, among which 2f-8e is a winding coil connected to the crown end, and the heads and tails of the two connected coils are welded together, that is, 8e and 14f are welded together.

[0064] The V phase and the W phase are similar to the U phase, and the lapped windings and the concentric windings are arranged alternately.

[0065] The stator winding is not limited to the hairpin flat wire motor with 48 slots and 8 poles, but is also applicable to the hairpin flat wire motor with 72 slots and 8 poles, 96 slots and 8 poles, 54 slots and 6 poles, and 72 slots and 6 poles.

[0066] The stator winding wiring method of the flat wire coil with 48 slots, 8 poles, 4 layers, 6 layers, 8 layers, and 1 branch, 2 branches, and 4 branches of the present invention adopts three different span combinations of Y-1 slot, Y slot, and Y+1 slot. The three branches of the winding have balanced potentials, which can avoid additional losses caused by circulating currents and improve motor efficiency. The winding structure is simple and compact, and the process manufacturability is good, which is suitable for batch applications.

[0067] The stator winding includes three-phase windings, each phase winding includes two groups of winding lines, the winding lines can be composed of multiple branches, and the branches include multiple coils; the number of layers of coils in each core slot increases from the bottom of the slot to the slot mouth, and the lead wires and the neutral point can be located on the innermost or outermost coil.

Claims

1. Hairpin type flat wire motor winding, characterized by: The invention comprises stator windings of various layers arranged in various stator slots of a stator core; the stator windings are formed with 2K slot layers, wherein K is a positive integer greater than 1; each of the stator windings comprises a plurality of individual flat wire coils; the flat wire coils are in a hairpin type, comprising two straight line segments (1) inserted in the stator slots, two pins (3) located at one end of the two straight line segments (1) and a connecting segment (2) connecting the other ends of the two straight line segments (1); the pins (3) extend outward; the two straight line segments (1) of each flat wire winding are respectively inserted into the 2i and 2i-1 slot layers, the straight line segment (1) inserted into the 2i slot layer is located on one side of the straight line segment (1) inserted into the 2i-1 slot layer in a first direction, i being an integer not less than 1; the first direction is a clockwise direction or a counterclockwise direction.

2. The hairpin flat wire motor winding according to claim 1, characterized in that: The stator winding of each phase is provided with two mixed windings of stacked winding and concentric winding, and the stacked winding and the concentric winding are arranged alternately; the stacked winding is composed of full-pitch coils, and the concentric winding is composed of a combination of short-pitch winding and long-pitch winding; the short-pitch winding and the long-pitch winding of the concentric winding are arranged alternately in the branch.

3. The hairpin flat wire motor winding according to claim 2, characterized in that: The number of stator slots provided in the stator core is 48, the number of motor poles is 8, the stator winding includes three phases, including U phase, V phase and W phase, the winding method of each phase stator winding is the same, each stator slot has 6 slot layers a, b, c, d, e, f, and each phase stator winding includes two branches in parallel; the V phase and W phase are similar to the U phase, and the lapped winding and concentric winding are arranged alternately.

4. The hairpin flat wire motor winding according to claim 3, characterized in that: The first part includes the first slot to the fourteenth slot, the first part is a lap winding, and the span of the winding under the two poles is Y; The first branch of the first part of the winding route is, Under the N pole, when i=1, the left straight line segment (1) of the winding coil at the crown end is in the f layer of slot 1, the right straight line segment (1) is in the e layer of the 7th slot, the span is 6, and the line layer is in the 1st and 2nd layers; the left straight line segment (1) of the winding coil at the welding end is in the e layer of slot 2, the right straight line segment (1) is in the f layer of the 8th slot, the span is 6, and the line layer is in the 1st and 2nd layers; Under the S pole, when i=1, the left straight line segment (1) of the winding coil at the crown end is in the f layer of slot 8, the right straight line segment (1) is in the e layer of the 14th slot, the span is 6, and the line layer is in the 1st and 2nd layers; the left straight line segment (1) of the winding coil at the welding end is in the e layer of slot 7, the right straight line segment (1) is in the f layer of the 13th slot, the span is 6, and the line layer is in the 1st and 2nd layers; The second branch of the first part has a winding route of Under the N pole, when i=1, the left straight line segment (1) of the winding coil at the crown end is in the f layer of slot 2, the right straight line segment (1) is in the e layer of the 8th slot, the span is 6, and the line layer is in the 1st and 2nd layers; the left straight line segment (1) of the winding coil at the welding end is in the e layer of slot 1, the right straight line segment (1) is in the f layer of the 7th slot, the span is 6, and the line layer is in the 1st and 2nd layers; Under the S pole, when i=1, the left straight line segment (1) of the winding coil at the crown end is in the f layer of slot 7, the right straight line segment (1) is in the e layer of the 13th slot, the span is 6, and the line layer is in the 1st and 2nd layers; the left straight line segment (1) of the winding coil at the welding end is in the e layer of slot 8, the right straight line segment (1) is in the f layer of the 14th slot, the span is 6, and the line layer is in the 1st and 2nd layers; The stator winding forms a lap winding after the first branch and the second branch are connected in parallel.

5. The hairpin flat wire motor winding according to claim 4, characterized in that: The second part includes the 13th slot to the 26th slot, the second part is a concentric winding, and the spans of the stator winding under each pole are Y+1 and Y-1 respectively; The winding span of the crown end of the first branch of the second part is Y+1, and the winding route is, Under the N pole, when i=1, the left straight line segment (1) of the crown winding coil is in the f layer of slot 13, and the right straight line segment (1) is in the e layer of slot 20, with a span of 7; the left straight line segment (1) of the winding coil at the welding end is in the e layer of slot 14, and the right straight line segment (1) is in the f layer of slot 19, with a span of 5; Under the S pole, when i=1, the left straight line segment (1) of the crown winding coil is in the f layer of slot 19, and the right straight line segment (1) is in the e layer of slot 26, and the span is 7; the left straight line segment (1) of the winding coil at the welding end is in the e layer of slot 20, and the right straight line segment (1) is in the f layer of slot 25, and the span is 5; The winding span of the crown end of the second branch of the second part is Y-1, and the winding route is, Under the N pole, when i=1, the left straight line segment (1) of the crown winding coil is in the f layer of slot 14, and the right straight line segment (1) is in the e layer of slot 19, and the span is 5; the left straight line segment (1) of the welding end winding coil is in the e layer of slot 13, and the right straight line segment (1) is in the f layer of slot 20, and the span is 7; Under the S pole, when i=1, the left straight line segment (1) of the crown winding coil is in the f layer of slot 20, and the right straight line segment (1) is in the e layer of slot 25, and the span is 5; the left straight line segment (1) of the winding coil at the welding end is in the e layer of slot 19, and the right straight line segment (1) is in the f layer of slot 26, and the span is 7; After the stator winding is connected in parallel in the first branch and the second branch, between the 13th slot and the 26th slot, the spans under the same pole are 5 and 7, both of which constitute concentric windings. The winding coils of the two connected slots form a concentric winding, and the winding with a span of 7 wraps the winding with a span of 5.

6. The hairpin flat wire motor winding according to claim 5, characterized in that: The U-phase winding is alternately arranged by stacking windings and concentric windings to form a complete winding of one phase; The winding sequence of the first branch of phase U is: 1f-7e-13f-20e-25f-31e-38f-43e-1d-7c-13d-20c-25d-31c-38d-43c-1b-7a-13b-20a-25b-31a-38b-43a-37a-32b-26a-19b-14a-8b-2a-44b-37c-32d-26c-19d-14c-8d-2c-44d-37e-32f-26e-19f-14e-8f-2e-44f, among which 1f-7e is a winding coil connected to the crown end, and the heads and tails of the two connected coils are welded together, that is, 7e and 13f are welded together; The winding sequence of the second branch of phase U is: 2f-8e-14f-19e-26f-32e-37f-44e-2d-8c-14d-19c-26d-32c-37d-44c-2b-8a-14b-19a-26b-32a-37b-44a-38a-31b-25a-20b-13a-7b-1a-43b-38c-31d-25c-20d-13c-7d-1c-43d-38e-31f-25e-20f-13e-7f-1e-43f, among which 2f-8e is a winding coil connected to the crown end, and the heads and tails of the two connected coils are welded together, that is, 8e and 14f are welded together.

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