A back-wound stator for an electric machine, a method of manufacture and a high speed permanent magnet electric machine

Abstract

The application provides a back-wound stator for an electric machine, a manufacturing method and a high-speed permanent magnet electric machine. The electric machine comprises a cylinder body, the cylinder body is formed with a shoulder, the back-wound stator comprises a stator core and a stator winding; the stator core is formed with a core main body, inner teeth and outer teeth, the inner teeth are formed with inner winding grooves, and the outer teeth are formed with outer winding grooves; the stator winding is wound around the core main body, the inner side end of the stator winding is located in the inner winding groove, and the outer side end of the stator winding is located in the outer winding groove; the radial distance between the outer edge of the stator winding and the inner edge of the shoulder is increased, so that the stator winding and the shoulder have a larger electrical gap, and short circuit accidents between the stator winding and the shoulder are avoided; a second slot wedge is arranged in the spacing groove, plays a radial limiting role on the first slot wedge, and avoids the first slot wedge from expanding outward to approach the cylinder body and the shoulder; the second slot wedge blocks the spacing groove, forces cooling gas to flow through the air gap between the stator and the rotor, and avoids the cooling performance from being deteriorated due to the change of the cooling flow channel.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of electric machines, and particularly relates to a back-wound stator for an electric machine, a manufacturing method and a high-speed permanent magnet electric machine. BACKGROUND

[0002] With the rapid development of China's economy and society, more and more occasions apply high-speed permanent magnet electric machines, such as air compressors, high-speed machine tools and vacuum pumps, etc. Such electric machines have great advantages in energy saving and emission reduction, etc. due to their high power density, high efficiency, fast dynamic response and small size. In the field of high-speed permanent magnet electric machines, to reduce the harmonics during operation of the electric machine, the stator often adopts a distributed stator winding. However, the end part of the distributed stator winding is high, which leads to a large axial length of the electric machine and a more elongated rotor, and the critical speed is lower. The back-wound stator structure can significantly shorten the end part size of the stator winding, thereby saving valuable axial space of the electric machine and widening the limit speed of the high-speed permanent magnet electric machine.

[0003] However, in the existing high-speed permanent magnet electric machine, the radial thickness of the outer yoke part of the stator core outer tooth is small, which leads to a too close distance between the stator winding and the shoulder of the electric machine cylinder, a small electrical gap, and an easy short circuit accident. In addition, the slot wedge that limits the stator winding interferes with the shoulder of the electric machine cylinder, which easily leads to misassembly of the stator. SUMMARY

[0004] In view of this, the present application provides a back-wound stator for an electric machine, a manufacturing method and a high-speed permanent magnet electric machine to solve the problems in the prior art that the small radial thickness of the outer yoke part of the stator core outer tooth leads to an easy short circuit between the stator winding and the shoulder and misassembly of the stator, etc.

[0005] The present application provides a back-wound stator for an electric machine, the electric machine comprising a cylinder, the cylinder being formed with a shoulder, the back-wound stator being arranged on the radially inner side of the cylinder, and the shoulder limiting the back-wound stator; the back-wound stator comprising a stator core and a stator winding; the stator core being formed with a core main body, an inner tooth and an outer tooth, the inner tooth being arranged on the radially inner side of the core main body and formed with an inner winding slot, and the outer tooth being arranged on the radially outer side of the core main body and formed with an outer winding slot; the stator winding being wound around the core main body, and the inner side end of the stator winding being located in the inner winding slot, and the outer side end of the stator winding being located in the outer winding slot.

[0006] The radial distance between the outer edge of the stator winding and the inner edge of the shoulder is Δh = h1 - h0 ≥ 5 mm, wherein h1 is the distance between the outer edge of the stator winding and the inner wall of the cylinder, and h0 is the radial thickness of the shoulder.

[0007] Further optionally, the outer tooth comprises an outer neck portion and an outer yoke portion, the outer yoke portion is connected with the outer edge of the core body through the outer neck portion, and the outer yoke portion and the outer edge of the core body form the outer winding slot;

[0008] The back-wound stator further comprises a first slot wedge, and the first slot wedge is arranged between the outer yoke portion and the stator winding.

[0009] The radial thickness of the outer yoke portion is h2, the radial thickness of the first slot wedge is h3, and h2+h3≥5mm and h2≥h0 are satisfied.

[0010] Further optionally, the outer tooth comprises a plurality of outer teeth, and the plurality of outer teeth are arranged along the circumference of the core body; the outer yoke portion comprises a first end and a second end, and the first end and the second end are oppositely arranged on both sides of the outer neck portion along the circumference of the core body; in the two adjacent outer yoke portions, a first outer winding sub-slot is formed between the first end of one of the outer yoke portions and the outer edge of the core body, and a second outer winding sub-slot is formed between the second end of the other outer yoke portion and the outer edge of the core body; the first outer winding sub-slot and the second outer winding sub-slot are communicated and form the outer winding slot.

[0011] In the two adjacent outer yoke portions, a spacing slot is formed between the second end of one of the outer yoke portions and the first end of the other outer yoke portion, and the spacing slot is communicated with the outer winding slot.

[0012] The back-wound stator further comprises a second slot wedge, and the second slot wedge is arranged in the spacing slot.

[0013] Further optionally, the spacing slot is formed with a first slot opening and a second slot opening, and the first slot opening and the second slot opening are oppositely arranged along the radial direction of the core body; the spacing slot is communicated with the outer winding slot through the first slot opening.

[0014] The circumferential width of the first slot opening is a1, the circumferential width of the second slot opening is a2, a1>a2, and a2 is related to the outer diameter and the slot number of the back-wound stator.

[0015] Further optionally, a2<1.5*a1.

[0016] Further optionally, the structure of the second slot wedge is matched with the structure of the spacing slot, the radial thickness of the second slot wedge is h4, and h4

[0017] Further optionally, the second slot wedge is arranged close to the outgoing line end of the back-wound stator, and the second slot wedge is located on the axial inner side of the outgoing line end of the back-wound stator.

[0018] Further optionally, an axial length of the stator core is c1, an axial length of the second slot wedge is c2, and -0.5*c1≤0.5*c1-c2≤0 is satisfied.

[0019] The application also provides a manufacturing method of the back-wound stator, which is any one of the back-wound stators for electric machines described above, and the manufacturing method comprises:

[0020] S1, winding the stator winding around the core body in the inner winding slot and the outer winding slot;

[0021] S2, disposing the first slot wedge between the outer yoke and the stator winding;

[0022] S3, disposing the second slot wedge in the interval slot;

[0023] S4, performing paint dipping or glue filling treatment on the back-wound stator.

[0024] The application also provides a high-speed permanent magnet motor, which comprises any one of the back-wound stators for electric machines described above or is manufactured by the manufacturing method described above.

[0025] Compared with the prior art, the application has the following beneficial effects:

[0026] (1) By thickening the radial thickness of the outer yoke of the outer tooth, the radial distance between the outer edge of the stator winding and the inner edge of the shoulder is increased, so that the stator winding and the shoulder have a larger electrical gap, the insulation distance between the stator winding and the shoulder is prolonged, and short circuit accidents between the two are avoided; the distance between the first slot wedge and the shoulder is increased, so that the stator and the cylinder have an assembly space, which ensures that the stator can be accurately assembled into the cylinder, the assembly precision of the stator is high, and the problem of out-of-position assembly of the stator caused by interference between the first slot wedge and the shoulder is solved;

[0027] (2) The second slot wedge is arranged in the interval slot, which plays a radial limiting role on the first slot wedge and avoids the first slot wedge from expanding outward to approach the cylinder and the shoulder; the interval slot is designed as a trapezoidal structure with a narrow outside and a wide inside, the second slot wedge is pushed in the interval slot by the outward expansion force of the stator winding, the second slot wedge is preliminarily fixed by friction force, and then complete fixation of the second slot wedge is realized through subsequent paint dipping or glue filling treatment;

[0028] (3) The second slot wedge strengthens the insulation strength between the stator winding and the shoulder, the second slot wedge blocks the interval slot, forces the cooling gas to flow through the air gap between the stator and the rotor, and avoids the deterioration of the cooling performance caused by the change of the cooling flow channel. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings required in the embodiments or prior art description. Obviously, the drawings in the following description are only exemplary, and for those skilled in the art, other drawings can be obtained from the provided drawings without creative labor.

[0030] The structures, proportions, sizes, etc. shown in the specification are only used to cooperate with the content disclosed in the specification, to be understood and read by those skilled in the art, and are not used to limit the conditions that the present application can be implemented, so they do not have technical significance. Any modification of structure, change of proportion relationship or adjustment of size, without affecting the effects and purposes that the present application can produce, should still fall within the scope of the technical content disclosed by the present application.

[0031] Figure 1 The stator core embodiment structure schematic diagram provided by the present application is shown in the figure.

[0032] Figure 2a The back-wound stator embodiment structure schematic diagram provided by the present application is shown in the figure.

[0033] Figure 2b The back-wound stator and cylinder embodiment assembly structure schematic diagram provided by the present application is shown in the figure.

[0034] Figure 3a 、 Figure 3b 、 Figure 3c And Figure 3d The back-wound stator (including size) embodiment partial structure schematic diagram provided by the present application is shown in the figure.

[0035] In the figure:

[0036] 1 - Stator core; 11 - Core body; 12 - Outer tooth; 121 - Outer neck; 122 - Outer yoke; 123 - First end; 124 - Second end; 13 - Outer winding slot; 14 - Interval slot; 141 - First slot opening; 142 - Second slot opening; 15 - Inner tooth; 16 - Inner winding slot;

[0037] 2 - Stator winding; 31 - First slot wedge; 32 - Second slot wedge; 4 - Stop shoulder; 5 - Cylinder. DETAILED DESCRIPTION

[0038] The following will be described by specific embodiments of the present application, familiar with the skilled person can easily understand the advantages and effects of the present application from the disclosure of the present application, it is clear that the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of the present application.

[0039] The terminology used in the embodiments of the present application is only for the purpose of describing specific embodiments, and is not intended to limit the present application. The singular forms "a", "said" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates otherwise. "Multiple" generally includes at least two, but does not exclude the case of including at least one.

[0040] It should be understood that the term "and / or" used herein is only to describe the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent the three cases of A alone, A and B together, and B alone. In addition, the character " / " in this paper generally represents that the front and rear associated objects are a "or" relationship.

[0041] It should also be noted that the terms "include", "contain" or any other variant thereof are intended to cover non-exclusive inclusion, so that the goods or systems including a series of elements not only include those elements, but also include other elements not explicitly listed, or include elements inherent in such goods or systems. Without more limitation, the element defined by the sentence "including a…" does not exclude the presence of other identical elements in the goods or systems including the element.

[0042] In the existing high-speed permanent magnet motor, the radial thickness of the outer yoke part of the stator core outer tooth is small, which leads to the distance between the stator winding and the shoulder of the motor cylinder being too close, the electrical clearance being small, and the short circuit accident being prone to occur; in addition, the slot wedge which limits the stator winding and the shoulder of the motor cylinder interfere, which is prone to cause the stator to be not in place during assembly;

[0043] The application creatively provides a back-wound stator for an electric machine, the electric machine comprising a cylinder body, the cylinder body being formed with a shoulder, the back-wound stator being arranged at the radial inner side of the cylinder body; the back-wound stator comprising a stator core and a stator winding; the stator core being formed with a core body, an inner tooth and an outer tooth, the inner tooth being arranged at the radial inner side of the core body and formed with an inner winding slot, the outer tooth being arranged at the radial outer side of the core body and formed with an outer winding slot; the stator winding being wound around the core body, and the inner side end of the stator winding being located in the inner winding slot, and the outer side end of the stator winding being located in the outer winding slot; the radial distance between the outer edge of the stator winding and the inner edge of the shoulder being Δh = h1 - h0 ≥ 5 mm, wherein h1 is the distance between the outer edge of the stator winding 2 and the inner wall of the cylinder body 5, and h0 is the radial thickness of the shoulder 4.

[0044] Increasing Δh makes the stator winding and the shoulder have a larger electrical gap, prolongs the insulation distance between the stator winding and the shoulder, and avoids short circuit accidents between the two; the stator and the cylinder body have an assembly space, which ensures that the stator can be accurately assembled into the cylinder body, the assembly precision of the stator is high, and the problem of inaccurate assembly of the stator is solved.

[0045] Further, as shown in Figure 1 , the inner tooth 15 comprises an inner neck portion and an inner yoke portion, the inner yoke portion being connected to the inner edge of the core body 11 through the inner neck portion, and the inner winding slot 16 being formed between the inner yoke portion and the inner edge of the core body 11; the outer tooth 12 comprises an outer neck portion 121 and an outer yoke portion 122, the outer yoke portion 122 being connected to the outer edge of the core body 11 through the outer neck portion 121, and the outer winding slot 13 being formed between the outer yoke portion 122 and the outer edge of the core body 11;

[0046] As shown in Figure 2a , Figure 2b and Figure 3c , the back-wound stator further comprises a first slot wedge 31, the first slot wedge 31 being arranged between the outer yoke portion 122 and the stator winding 2, and playing a limiting role on the stator winding 2, avoiding the problem of electrical short circuit caused by the outward expansion of the stator winding 2 to approach the cylinder body 5 and the shoulder 4;

[0047] As shown in Figure 3a , Figure 3b and Figure 3dAs shown, the radial thickness of the outer yoke part 122 is h2, the radial thickness of the first slot wedge 31 is h3, and h2+h3≥5mm, h2≥h0; therefore, h2 or h3 can be increased to increase Δh; preferably, increasing h2 can improve the insulation strength between the stator winding 2 and the shoulder 4, increase the distance between the first slot wedge 31 and the shoulder 4, so that the first slot wedge 31 no longer interferes with the shoulder 4, prevents the wire package of the stator winding 2 from expanding outward to approach the shoulder 4, and provides a space between the stator and the cylinder 5, ensuring that the stator can be accurately assembled into the cylinder, and the assembly precision of the stator is high, solving the problem that the interference between the first slot wedge 31 and the shoulder 4 causes the stator to not be assembled in place.

[0048] It should be noted that h2 can be set according to actual conditions, and is generally greater than the radial thickness of the shoulder 4 compared to the radial thickness of the outer yoke part 122.

[0049] As shown in Figure 1 , the outer teeth 12 include a plurality of, and the plurality of outer teeth 12 are arranged along the circumference of the core body 11; the outer yoke part 122 includes a first end 123 and a second end 124, and the first end 123 and the second end 124 are arranged on both sides of the outer neck part 121 along the circumference of the core body 11; among the two adjacent outer yoke parts 122, the first end 123 of one outer yoke part 122 and the outer edge of the core body 11 form a first outer winding sub-slot, and the second end 124 of the other outer yoke part 122 and the outer edge of the core body 11 form a second outer winding sub-slot; the first outer winding sub-slot and the second outer winding sub-slot are connected and form an outer winding slot 13; the first slot wedge 31 includes a plurality of, and each first slot wedge 31 is arranged between the corresponding outer yoke part 122 and the stator winding 2;

[0050] Among the two adjacent outer yoke parts 122, the second end 124 of one outer yoke part 122 and the first end 123 of the other outer yoke part 122 form a spacing slot 14, and the spacing slot 14 is communicated with the outer winding slot 13;

[0051] As shown in Figure 2a , Figure 2b and Figure 3c , in order to solve the problem that the first slot wedge 31 is not fixed firmly and is easy to contact the shoulder 4, the back-wound stator further includes a second slot wedge 32, and the second slot wedge 32 is arranged in the spacing slot 14; the second slot wedge 32 plays a radial limiting role on the first slot wedge 31, avoiding the first slot wedge 31 and the stator winding 2 from expanding outward to approach the cylinder 5 and the shoulder 4; in addition, the first slot wedge 31 and the second slot wedge 32 separate the stator winding 2 from the shoulder 4, playing an insulation role and improving the insulation strength between the stator winding 2 and the shoulder 4;

[0052] Further, the spacing groove 14 is designed as a trapezoidal structure with the outside narrow and the inside wide, and the second slot wedge 32 is pushed in the spacing groove 14 by the force of the outward expansion of the stator winding 2, and the second slot wedge 32 is preliminarily fixed by the friction force between the wall surface of the spacing groove 14 and the wall surface of the second slot wedge 32, and then the second slot wedge 32 is completely fixed through subsequent paint or glue filling treatment; specifically, the spacing groove 14 is formed with a first slot opening 141 and a second slot opening 142, and the first slot opening 141 and the second slot opening 142 are oppositely arranged along the radial direction of the core body 11; the spacing groove 14 is communicated with the outer winding groove 13 through the first slot opening 141;

[0053] As shown in Figure 3b , the circumferential width of the first slot opening 141 is a1, the circumferential width of the second slot opening 142 is a2, a1>a2, and a2 is related to the outer diameter and the slot number of the back-wound stator; the circumferential width of the first slot opening 141 and the circumferential width of the second slot opening 142 are both smaller than the circumferential width of the outer winding groove 13; a1 and a2 are both designed with certain requirements, a1 should not be too large, otherwise the stress area of the first slot wedge 31 will be too small, and the middle part of the first slot wedge 31 will be easily deformed under stress; a2 should not be too small, otherwise the stator offline efficiency will be reduced;

[0054] Preferably, a1<1.5*a2.

[0055] As shown in Figure 3b and Figure 3d , in addition, in view of the problem that the radial thickness of the second slot wedge 32 is too large and interference with the cylinder 5 easily leads to the stator assembly out of position, the structure of the second slot wedge 32 in this embodiment is designed to be matched with the structure of the spacing groove 14, and the radial thickness of the second slot wedge 32 is h4, and h4<h2; specifically, the radial thickness of the second slot wedge 32 is slightly smaller than the radial thickness of the outer yoke portion 122, so that the second slot wedge 32 blocks the air duct of the spacing groove 14, but does not exceed the outer edge of the outer yoke portion 122, otherwise the stator and the cylinder 5 will interfere with each other when the stator is assembled;

[0056] The second slot wedge 32 strengthens the insulation strength between the stator winding 2 and the stop shoulder 4, the second slot wedge 32 blocks the spacing groove 14, forcing the cooling gas to flow through the air gap between the stator and the rotor, avoiding the change of the cooling flow channel to cause the deterioration of the cooling performance.

[0057] In view of the problem that the unreasonable position setting of the second slot wedge 32 leads to the back-wound stator assembly out of position, this embodiment proposes that the second slot wedge 32 is arranged close to the outgoing end of the back-wound stator, and the second slot wedge 32 is located on the inner side of the outgoing end of the back-wound stator in the axial direction, and the second slot wedge 32 does not exceed the end surface of the corresponding core body 11 after assembly, avoiding the problem that the stator assembly is out of position when the stator is assembled into the inside of the cylinder.

[0058] Preferably, the axial length of the stator core 1 is c1, the axial length of the second slot wedge 32 is c2, and -0.5*c1≤0.5*c1-c2≤0 is satisfied. The c2 has certain requirements, and the c2 should not be too large. After the second slot wedge 32 is assembled, the end face of the second slot wedge 32 should not exceed the end face of the core body 11 at the outgoing end of the stator, otherwise the stator assembly will not be in place. In addition, the c2 should not be too small, otherwise it is difficult to assemble the second slot wedge 32.

[0059] The embodiment also provides a manufacturing method of the back-wound stator. The back-wound stator is any one of the back-wound stators for electric machines described above, and the manufacturing method comprises:

[0060] S1, when the stator is wired, the stator winding 2 is wound in the inner winding slot 16 and the outer winding slot 13 around the core body 11. Specifically, the inner side end of the stator winding 2 is located in the inner winding slot 16, and the outer side end of the stator winding 2 is located in the outer winding slot 13;

[0061] S2, the first slot wedge 31 is arranged between the corresponding outer yoke 122 and the stator winding 2;

[0062] S3, the second slot wedge 32 is arranged in the corresponding interval slot 14. After the winding is completed, the stator winding 2 is compressed by the first slot wedge 31, and the stator winding 2 has a tendency to expand away from the outer side of the core body 11. After the second slot wedge 32 is compressed to the first slot wedge 31, the first slot wedge 31 will press the second slot wedge 32 in the interval slot 14, so as to realize the preliminary fixation of the second slot wedge 32;

[0063] S4, when the stator is completed, the back-wound stator is treated by dipping paint or pouring glue, and the insulation paint or pouring glue completely fixes the second slot wedge 32.

[0064] The embodiment also provides an electric machine, which comprises the back-wound stator for electric machines described above or is manufactured by the manufacturing method of the back-wound stator described above. The back-wound stator can significantly shorten the end size of the stator winding 2 of the electric machine, thereby saving the valuable axial space of the electric machine and widening the limit speed of the high-speed permanent magnet electric machine.

[0065] The exemplary embodiments of the present disclosure are specifically shown and described above. It should be understood that the present disclosure is not limited to the detailed structure, arrangement or implementation method described herein; on the contrary, the present disclosure is intended to cover various modifications and equivalent arrangements within the spirit and scope of the appended claims.

Claims

1. A back-wound stator for an electric motor, the electric motor comprising a cylindrical body (5) having a shoulder (4) formed thereon, the back-wound stator being disposed radially inside the cylindrical body (5), the shoulder (4) serving to limit the back-wound stator; characterized in that, The back-wound stator includes a stator core (1) and a stator winding (2); the stator core (1) has a core body (11), inner teeth (15) and outer teeth (12), the inner teeth (15) are located on the radial inner side of the core body (11) and form an inner winding slot (16), the outer teeth (12) are located on the radial outer side of the core body (11) and include an outer neck (121) and an outer yoke (122), the outer yoke (122) is connected to the outer edge of the core body (11) through the outer neck (121), and an outer winding slot (13) is formed between the outer yoke (122) and the outer edge of the core body (11); the stator winding (2) is wound around the core body (11), and the inner end of the stator winding (2) is located in the inner winding slot (16), and the outer end is located in the outer winding slot (13); The radial distance between the outer edge of the stator winding (2) and the inner edge of the shoulder (4) is Δh = h1 - h0 ≥ 5 mm; where h1 is the distance between the outer edge of the stator winding (2) and the inner wall of the cylinder (5), and h0 is the radial thickness of the shoulder (4). The back-wound stator further includes a first slot wedge (31), which is disposed between the outer yoke (122) and the stator winding (2); the radial thickness of the outer yoke (122) is h2, and the radial thickness of the first slot wedge (31) is h3, satisfying: h2+h3≥5mm, h2≥h0; The external teeth (12) include a plurality of teeth, which are arranged circumferentially along the core body (11); the external yoke (122) includes a first end (123) and a second end (124) arranged opposite to each other on both sides of the outer neck (121) along the circumferential direction of the core body (11); In two adjacent outer yokes (122), a first outer winding sub-slot is formed between the first end (123) of one outer yoke (122) and the outer edge of the core body (11), and a second outer winding sub-slot is formed between the second end (124) of the other outer yoke (122) and the outer edge of the core body (11); the first outer winding sub-slot and the second outer winding sub-slot are connected to form the outer winding slot (13); in two adjacent outer yokes (122), a spacer slot (14) is formed between the second end (124) of one outer yoke (122) and the first end (123) of the other outer yoke (122), and the spacer slot (14) is connected to the outer winding slot (13); The back-wound stator also includes a second slot wedge (32), which is disposed in the spacer slot (14).

2. The back-wound stator for an electric motor according to claim 1, characterized in that, The spacer slot (14) has a first slot (141) and a second slot (142), and the first slot (141) and the second slot (142) are arranged opposite each other along the radial direction of the iron core body (11); the spacer slot (14) is connected to the outer winding slot (13) through the first slot (141); The circumferential width of the first slot (141) is a1, and the circumferential width of the second slot (142) is a2, where a1 > a2, and a2 is related to the outer diameter and number of slots of the back-wound stator.

3. The back-wound stator for an electric motor according to claim 2, characterized in that, a1 < 1.5 * a2.

4. The back-wound stator for an electric motor according to claim 1, characterized in that, The structure of the second groove wedge (32) is adapted to the structure of the spacer groove (14), and the radial thickness of the second groove wedge (32) is h4, and h4 < h2.

5. The back-wound stator for an electric motor according to claim 1, characterized in that, The second slot wedge (32) is disposed near the output end of the back-wound stator, and the second slot wedge (32) is located on the axial inner side of the output end of the back-wound stator.

6. The back-wound stator for an electric motor according to claim 5, characterized in that, The axial length of the stator core (1) is c1, and the axial length of the second slot wedge (32) is c2, satisfying -0.5*c1≤0.5*c1-c2≤0.

7. A method for manufacturing a back-wound stator, characterized in that, The back-wound stator is the back-wound stator for a motor as described in any one of claims 1-6, and the manufacturing method includes: S1. The stator winding (2) is wound around the iron core body (11) in the inner winding slot (16) and the outer winding slot (13); S2. The first slot wedge (31) is placed between the corresponding outer yoke (122) and the stator winding (2); S3. The second slot wedge (32) is placed in the corresponding spacer slot (14); S4. The back-wound stator is impregnated with paint or glue.

8. A high-speed permanent magnet motor, characterized in that, The high-speed permanent magnet motor includes the back-wound stator for motor as described in any one of claims 1-6 or the manufacturing method of the back-wound stator as described in claim 7.

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