stator

Abstract

The present invention provides a stator. The stator is miniaturized. The stator is provided in a rotating electrical machine and comprises: a stator core having a plurality of slots; and a distributed winding coil (Cu) having a plurality of segment coils accommodated in a pair of slots in the plurality of slots, the plurality of segment coils being connected to one another. The distributed winding coil (Cu) has the following coil structure: a plurality of parallel coils connecting the plurality of segment coils accommodated in the same pair of slots in the plurality of slots in parallel to one another, the plurality of parallel coils being connected to one another in series, and a plurality of segment coils (A1, B1) constituting each parallel coil (P1) being arranged radially adjacent to one another within slots (S1, S43).

Description

Technical Field

[0001] The present invention relates to a stator provided in a rotating electric machine. Background Art

[0002] Rotating electrical machines such as motors and generators are equipped with stators that generate magnetic fields. Furthermore, to achieve higher torque and smaller size in rotating electrical machines, rotating electrical machines employing stator coils composed of multiple segment coils have been proposed (see Patent Documents 1 and 2). In such rotating electrical machines, multiple segment coils, bent in a roughly U-shaped pattern, are inserted into slots in a stator core, and the multiple segment coils are connected to form a single conductor.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent No. 4453669

[0006] Patent Document 2: Japanese Patent No. 3864878 Summary of the Invention

[0007] Technical issues

[0008] However, in order to further miniaturize the stator provided in the rotating electrical machine, it is required to reduce the coil ends of the stator coil. Therefore, it is required to reduce the coil ends by appropriately arranging the segment coils relative to the slots of the stator core to achieve stator miniaturization.

[0009] An object of the present invention is to achieve miniaturization of a stator.

[0010] Technical Solution

[0011] A stator according to the present invention is provided in a rotating electrical machine, the stator comprising: a stator core having a plurality of slots formed therein; and a distributed winding coil including a plurality of segment coils accommodated in a pair of slots among the plurality of slots, the plurality of segment coils being connected to one another. The distributed winding coil has a coil structure comprising a plurality of parallel coils, the parallel coils being formed by connecting a plurality of the segment coils accommodated in the same pair of slots among the plurality of slots in parallel, the plurality of parallel coils being connected to one another in series, and the plurality of segment coils constituting each parallel coil being arranged radially adjacent to one another within the slots.

[0012] Effects of the Invention

[0013] According to the present invention, the plurality of segment coils constituting each parallel coil are arranged radially adjacent to each other within the slots. This allows the segment coils to be arranged without complicated bending, thus enabling the stator to be miniaturized. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a cross-sectional view showing an example of a rotating electrical machine including a stator according to an embodiment of the present invention.

[0015] Figure 2 It is along Figure 1 Line AA shows a cross-sectional view of the stator.

[0016] Figure 3 It is a perspective view showing a segment coil as an example.

[0017] Figure 4 It is a perspective view showing a stator core including a U-phase distributed winding coil.

[0018] Figure 5 It is a cross-sectional view showing a stator core including a U-phase coil.

[0019] Figure 6 It is a perspective view showing the U-phase coil alone.

[0020] Figure 7 It is a diagram showing the coil structure of the U-phase coil.

[0021] Figure 8 This is a diagram showing the connection state of the three-phase coils.

[0022] Figure 9 This is a diagram showing the connection relationship of the segment coils constituting a part of the U-phase coil.

[0023] Figure 10 It is a diagram showing the accommodation position of the segment coil relative to the slots of the stator core.

[0024] Figure 11 It is a diagram showing the accommodation position of the segment coil relative to the slots of the stator core.

[0025] Figure 12 This is an enlarged view showing the accommodation position of the segment coil relative to the slot of the stator core.

[0026] Figure 13 This diagram shows the assembly process of the stator and rotor.

[0027] Explanation of symbols

[0028] 10: Stator

[0029] 11: Rotating motor

[0030] 15: stator core

[0031] 20: Rotor

[0032] 30: Segmented coil

[0033] 31: Coil side (straight part)

[0034] 32: Coil side (straight part)

[0035] 33: Bend

[0036] 34, 35: Welding ends

[0037] 40: One end face

[0038] 41: The other end

[0039] S1~S48:slot

[0040] A1~A32: Segment coil

[0041] B1~B32: Segment coil

[0042] P1~P32: Parallel coils

[0043] a12, a21, a22, a31, a32, a41, a42, a51: welded ends

[0044] b12, b21, b22, b31, b32, b41, b42, b51: Welded ends

[0045] Ce1: 1st coil end

[0046] Ce2: 2nd coil end

[0047] SC: three-phase coil, stator coil

[0048] Cu: U-phase coil (distributed winding coil)

[0049] Cv: V-phase coil (distributed winding coil)

[0050] Cw: W-phase coil (distributed winding coil) DETAILED DESCRIPTION

[0051] Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. In the following description, a three-phase synchronous motor generator such as that installed in an electric vehicle or hybrid vehicle is used as an example of a rotating electrical machine 11 equipped with a stator 10 according to one embodiment of the present invention. However, the present invention is not limited to this embodiment and may be any rotating electrical machine as long as it has a stator equipped with distributed winding coils.

[0052] [Rotating Electric Machine Structure]

[0053] Figure 1 1 is a cross-sectional view showing an example of a rotating electrical machine 11 including a stator 10 according to an embodiment of the present invention. Figure 1As shown, a rotating electrical machine 11 serving as an electric generator has a motor housing 12. The motor housing 12 includes a cylindrical housing body 13 with a bottom, and an end cap 14 that closes the open end of the housing body 13. The stator 10, fixed within the housing body 13, includes a cylindrical stator core 15 formed from a plurality of silicon steel sheets, etc., and a three-phase stator coil SC (hereinafter referred to as a three-phase coil SC) assembled on the stator core 15. Furthermore, a high-voltage connector 16 for connection to an inverter (not shown) is provided on the end cap 14. Power line terminals Pu, Pv, and Pw extending from the three-phase coil SC are connected to the high-voltage connector 16.

[0054] A cylindrical rotor 20 is rotatably housed in the center of the stator core 15. The rotor 20 includes a cylindrical rotor core 21 formed from a plurality of silicon steel sheets, a plurality of permanent magnets 22 embedded in the rotor core 21, and a rotor shaft 23 fixed to the center of the rotor core 21. One end of the rotor shaft 23 is supported by a bearing 24 provided on the wall 13a of the housing body 13, while the other end of the rotor shaft 23 is supported by a bearing 25 provided on the end cover 14.

[0055] [Stator structure]

[0056] Figure 2 It is along Figure 1 The AA line shows a cross-sectional view of the stator 10 , Figure 3 : is a perspective view showing a segment coil 30 as an example. Figure 4 1 is a perspective view showing a stator core 15 having a U-phase distributed winding coil (hereinafter referred to as a U-phase coil Cu). Figure 5 : is a cross-sectional view showing the stator core 15 including the U-phase coil Cu. Figure 6 This is a perspective view showing the U-phase coil Cu as a single unit. It should be noted that the U-phase coil Cu refers to the distributed winding coil that constitutes one phase of the three-phase coil SC. As described later, the three-phase coil SC is composed of a V-phase distributed winding coil (hereinafter referred to as the V-phase coil Cv) and a W-phase distributed winding coil (hereinafter referred to as the W-phase coil Cw) in addition to the U-phase coil Cu.

[0057] like Figure 2As shown, a plurality of slots S1 to S48 are formed at predetermined intervals along the circumferential direction on the inner circumference of the cylindrical stator core 15. Each slot S1 to S48 accommodates a segment coil 30, described below, and a plurality of segment coils 30 are connected to form a three-phase coil SC. In the illustrated example, slots S1, S2, S7, S8, etc. accommodate the segment coils 30 forming the U-phase coil Cu; slots S3, S4, S9, S10, etc. accommodate the segment coils 30 forming the V-phase coil Cv; and slots S5, S6, S11, S12, etc. accommodate the segment coils 30 forming the W-phase coil Cw.

[0058] like Figure 3 As shown, the segmented coil 30 bent in a roughly U-shape has: a coil side (straight portion) 31 accommodated in a certain slot (for example, slot S1), and a coil side (straight portion) 32 accommodated in another slot (for example, slot S7) at a predetermined coil pitch. In addition, the segmented coil 30 has a bent portion 33 connecting a pair of coil sides 31 and 32 to each other, and welded ends 34 and 35 extending from the pair of coil sides 31 and 32, respectively. It should be noted that the segmented coil 30 is composed of a flat wire (rectangular wire) including a conductive material such as copper, and an insulating film such as enamel or resin film is provided on the segmented coil 30 except for the front end of the welded ends 34 and 35. In addition, the bent portion 33 of the segmented coil 30 is not limited to Figure 3 The bent shapes shown have various bent shapes depending on the assembly position to the stator core 15 .

[0059] like Figure 4 and Figure 5 As shown in FIG. 1 , a plurality of segment coils 30 are assembled in the stator core 15. The segment coils 30 include a pair of coil sides 31 and 32 separated by a predetermined coil pitch (for example, 6 slots). Figure 4 As shown, bent portion 33 of segment coil 30 protrudes from one end surface 40 of stator core 15, and welded ends 34, 35 of segment coil 30 protrude from the other end surface 41 of stator core 15. Furthermore, welded ends 34, 35 protruding from the other end surface 41 of stator core 15 are bent so as to contact welded ends 34, 35 of other segment coils 30 constituting U-phase coil Cu, and are then welded to the welded ends 34, 35 of the other segment coils 30 in contact. Figure 6 As shown, multiple segment coils 30 are connected to form a single conductor, forming a U-phase coil Cu. An end group 42 consisting of welded end portions 34 and 35 joined together is subjected to an insulation coating process such as forming a resin film to cover the conductor.

[0060] Figure 7 : is a diagram showing the coil structure of the U-phase coil Cu, Figure 8This diagram shows the connection state of the three-phase coils SC. While the following description focuses on the U-phase coil Cu, the V-phase coil Cv and the W-phase coil Cw also have the same coil structure. It should be noted that while the segment coils were denoted by the symbol "30" in the above description, the following description uses the symbols "A1-A32, B1-B32" to distinguish the individual segment coils.

[0061] like Figure 7 As shown, the U-phase coil Cu has a plurality of parallel coils P1 to P32 connected in series. In addition, each parallel coil (P1···) is composed of a pair of segment coils (A1, B1···) connected in parallel. In addition, the pair of segment coils (A1, B1···) constituting each parallel coil (P1···) is accommodated in the same pair of slots (S1, S43···). In other words, Figure 7 As shown, the pair of segment coils A1 and B1 that constitute parallel coil P1 are housed in the same pair of slots S1 and S43. Furthermore, for example, the pair of segment coils A10 and B10 that constitute parallel coil P10 are housed in the same pair of slots S19 and S25. Furthermore, for example, the pair of segment coils A20 and B20 that constitute parallel coil P20 are housed in the same pair of slots S38 and S44.

[0062] like Figure 8 As shown, one end of the U-phase coil Cu is connected to the power line terminal Pu, and the other end of the U-phase coil Cu is connected to the neutral point terminal PN. Similarly, one end of the V-phase coil Cv is connected to the power line terminal Pv, and the other end of the V-phase coil Cv is connected to the neutral point terminal PN. Similarly, one end of the W-phase coil Cw is connected to the power line terminal Pw, and the other end of the W-phase coil Cw is connected to the neutral point terminal PN. Furthermore, the U-phase coil Cu, the V-phase coil Cv, and the W-phase coil Cw are connected to each other via the neutral point terminal PN, and the coils Cu, Cv, and Cw of each phase form a three-phase coil SC.

[0063] As mentioned above Figure 7 As shown, in the U-phase coil Cu, one phase of the three-phase coil SC, the multiple segment coils (A1, B1...) that constitute each parallel coil (P1...) are housed in the same pair of slots (S1, S43...). This prevents potential differences from occurring between the segment coils (A1, B1...), and prevents circulating currents from occurring within each parallel coil (P1...). In other words, the electromotive force generated by the rotor during rotation is made uniform across the multiple segment coils that constitute each parallel coil, preventing circulating currents from occurring within each parallel coil. It should be noted that circulating currents can also be prevented within each parallel coil in the V-phase coil Cv and W-phase coil Cw, which have the same coil structure.

[0064] [U-phase coil structure]

[0065] Next, the structure of the U-phase coil Cu will be described in detail. Figure 9 : is a diagram showing the connection relationship of the segment coils A1 to A8 and B1 to B8 constituting a part of the U-phase coil Cu. Figure 10 : is a diagram showing the accommodation positions of the segment coils A1 to A16 and B1 to B16 relative to the slots S1, S7, etc. of the stator core 15. Figure 11 : This is a diagram showing the accommodation positions of the segment coils A17 to A32 and B17 to B32 relative to the slots S2 and S8 of the stator core 15. Figure 12 The diagram shows, in an enlarged manner, the accommodation positions of segment coils A1 to A7 and B1 to B7 relative to slots S1 , S37 , and S43 of stator core 15 .

[0066] Figures 10 to 12 The "power line side" shown is as follows Figure 1 and Figure 4 The side shown in FIG. 1 is where the welded ends 34 and 35 of the segment coil 30 are located, that is, where the power line terminals Pu, Pv, and Pw are located. Figure 10 The "reverse power line side" shown in Figure 1 and Figure 4 As shown, it refers to the side opposite to the power line side, that is, the side where the bent portion 33 of the segment coil 30 is located. Figure 10 and Figure 11 The "inside" shown is as Figure 5 As shown, it is the radial inner side of the stator core 15, Figure 10 The “outside” shown in the above description refers to the radially outer side of the stator core 15 .

[0067] First, if Figure 7 As shown in FIG. 1 , the U-phase coil Cu has a coil structure in which the connection method of four parallel coils (for example, P1 to P4) is repeated. The connection method of the parallel coils P1 to P4 will be described below. Figure 9 and Figure 10 As shown, segment coils A1 to A3 and B1 to B3 constituting parallel coils P1 to P3 are inserted into the same pair of slots S1 and S43. Segment coils A4 and B4 constituting parallel coil P4 are inserted into the same pair of slots S43 and S37, including slot S43 shared with parallel coils P1 to P3.

[0068] In more detail, Figure 10 and Figure 12As shown, segment coils A1 and B1 of parallel coil P1 are accommodated in the first and second positions (outer positions) of slots S1 and S43. Furthermore, segment coils A2 and B2 of parallel coil P2 are accommodated in the third and fourth positions of slot S1 and the fifth and sixth positions of slot S43. Furthermore, segment coils A3 and B3 of parallel coil P3 are accommodated in the seventh and eighth positions (inner positions) of slots S1 and S43. Furthermore, segment coils A4 and B4 of parallel coil P4 are accommodated in the third and fourth positions of slot S43 and the fifth and sixth positions of slot S37.

[0069] And, as Figure 9 and Figure 12 As shown, between the power line-side slots S1 and S43, the welded ends a12 and b12 of the segment coils A1 and B1 protruding from slot S43 and the welded ends a21 and b21 of the segment coils A2 and B2 protruding from slot S1 are overlapped and welded at a single location as an end group W12. Similarly, between the power line-side slots S1 and S43, the welded ends a22 and b22 of the segment coils A2 and B2 protruding from slot S43 and the welded ends a31 and b31 of the segment coils A3 and B3 protruding from slot S1 are overlapped and welded at a single location as an end group W23.

[0070] Furthermore, between the power line-side slots S43 and S37, the welded ends a32 and b32 of segment coils A3 and B3 protruding from slot S43 and the welded ends a41 and b41 of segment coils A4 and B4 protruding from slot S37 are overlapped and welded together at a single location as an end group W34. Similarly, between the power line-side slots S43 and S37, the welded ends a42 and b42 of segment coils A4 and B4 protruding from slot S43 and the welded ends a51 and b51 of segment coils A5 and B5 protruding from slot S37 are overlapped and welded together at a single location as an end group W45.

[0071] In this way, by connecting the segment coils A1 to A5 and B1 to B5 via the end groups W12, W23, W34, and W45, a plurality of parallel coils P1 to P4 can be formed, and the parallel coils P1 to P4 can be connected in series. Figure 10 and Figure 11 As shown, by repeating the connection method of the parallel coils P1 to P4 for every four parallel coils (P5 to P8, P9 to P12, etc.), a U-phase coil Cu composed of the parallel coils P1 to P32 can be formed.

[0072] [Miniaturization of coil ends]

[0073] If using Figure 9 and Figure 12 As described above, by connecting the segment coils A1 to A5 and B1 to B5 via the end groups W12, W23, W34, and W45, multiple parallel coils P1 to P4 can be formed, and the parallel coils P1 to P4 can be connected in series. In this way, by fusing the four welded ends (a12, b12, a21, b21, etc.) into one end group (W12, etc.), the number of end groups (W12, etc.) used as welded locations can be reduced, and the coil end Ce2 including the end group (W12, etc.) can be miniaturized. In other words, Figure 4 As shown, since insulation distances must be maintained between the end groups 42, increasing the number of end groups 42 tends to cause the end groups 42 to be positioned radially outward (in the direction of arrow α). However, reducing the number of end groups 42 prevents the coil ends Ce2 from expanding radially outward. Furthermore, since the number of weld locations is significantly reduced, the manufacturing cost of the stator 10 can be reduced.

[0074] In addition, the end group W12 is used as an example for explanation. Figure 12 As shown, the coil sides of segment coils A1 and B1 constituting parallel coil P1 are arranged adjacent to each other within slot S43, while the coil sides of segment coils A2 and B2 constituting parallel coil P2 are arranged adjacent to each other within slot S1. Consequently, when segment coils A1 and B1 form parallel coil P1, welded ends a12 and b12 can be simply overlapped and connected. When segment coils A2 and B2 form parallel coil P2, welded ends a21 and b21 can be simply overlapped and connected. This simple overlap and welding of welded ends a12, b12, a21, and b21 prevents complex overlapping of the welded ends a12, b12, a21, and b21, and allows for a smaller coil end Ce2.

[0075] Furthermore, using end group W12 as an example, segment coils A1 and B1 of parallel coil P1 are arranged at the first and second positions within slot S43, while segment coils A2 and B2 of parallel coil P2 are arranged at the third and fourth positions within slot S1. By radially staggering coils A1 and B1 and coils A2 and B2 in this manner, the welded ends a12, b12, a21, and b21 can be simply overlapped and connected. Even when parallel coils P1 and P2 are connected in series, the welded ends a12, b12, a21, and b21 can be simply overlapped and welded. This prevents complex overlapping of the individual welded ends a12, b12, a21, and b21, thus enabling a reduction in the size of coil end Ce2.

[0076] [Inner diameter of coil end]

[0077] Figure 13 1 is a diagram showing the assembly process of the stator 10 and the rotor 20. Figure 13 As shown, the stator core 15 of the stator 10 is provided with a three-phase coil SC consisting of coils Cu, Cv, and Cw for each phase. These three-phase coils SC, namely the coils Cu, Cv, and Cw for each phase, have a first coil end Ce1 consisting of a plurality of bent portions 33 protruding from one end surface 40 of the stator core 15, and a second coil end Ce2 consisting of a plurality of welded ends 34 and 35 protruding from the other end surface 41 of the stator core 15. The inner diameter D1 of the first coil end Ce1, located on the reverse power line side, is smaller than the inner diameter D2 of the second coil end Ce2, located on the power line side. Furthermore, the inner diameter D1 of the first coil end Ce1 is smaller than the inner diameter D3 of the stator core 15. Furthermore, the inner diameter D1 of the first coil end Ce1 is smaller than the outer diameter D4 of the rotor 20. It should be noted that the inner diameter D2 of the second coil end Ce2 is larger than the outer diameter D4 of the rotor 20.

[0078] like Figure 10 and Figure 11 As shown, on the anti-power line side of the first coil end Ce1, the number of segment coils A1-A32 and B1-B32 spanning the slots varies. In contrast, on the power line side of the second coil end Ce2, the number of segment coils A1-A32 and B1-B32 spanning the slots is uniform. This means that on the anti-power line side of the first coil end Ce1, the segment coils A1-A32 and B1-B32 are more likely to be arranged in a complex manner, which tends to increase the volume of the coil end Ce1. In contrast, on the power line side of the second coil end Ce2, the segment coils A1-A32 and B1-B32 can be more simply arranged, reducing the volume of the coil end Ce2.

[0079] Therefore, in the stator 10 of one embodiment of the present invention, the first coil end Ce1 is allowed to expand radially inwardly of the stator core 15, and the volume is reduced by reducing the outer diameter D5 of the second coil end Ce2. As a result, the second coil end Ce2 can be prevented from expanding radially outwardly, so that the insulation distance with the housing body 13 can be easily ensured, that is, since the housing body 13 can be miniaturized, the size of the rotating motor 11 can be reduced. In addition, even in the case where the first coil end Ce1 is increased due to the effect of reducing the second coil end Ce2, the size of the rotating motor 11 can be maintained small by expanding the first coil end Ce1 radially inwardly. In addition, even in the case where the inner diameter D1 of the first coil end Ce1 becomes smaller than the inner diameter D3 of the stator core 15 and the outer diameter D4 of the rotor 20 due to the expansion of the first coil end Ce1 radially inwardly, due to the following Figure 13As shown by the hollow arrow, the rotor 20 is inserted into the stator core 15 from the second coil end Ce2 side, so that the rotating electrical machine 11 can be assembled appropriately.

[0080] The present invention is not limited to the above-described embodiment and can, of course, be modified in various ways without departing from the spirit of the present invention. In the above description, two segment coils are used to form a single parallel coil. However, this is not limiting. A parallel coil can also be formed by connecting three or more segment coils in parallel. For example, when three segment coils are used to form a parallel coil, the three segment coils are arranged adjacent to each other within the same pair of slots. Furthermore, when three segment coils are used to form a parallel coil, six welded end portions form a single end group.

[0081] In the above description, a stator core 15 having 48 slots is used, but the present invention is not limited to this, and stator cores having other slot numbers may also be used. In addition, in the above description, the U-phase coil Cu, V-phase coil Cv, and W-phase coil Cw are connected using a so-called Y connection, but the present invention is not limited to this, and the U-phase coil Cu, V-phase coil Cv, and W-phase coil Cw may also be connected using a so-called Δ connection. In addition, in the above description, the stator coil SC is composed of the U-phase coil Cu, V-phase coil Cv, and W-phase coil Cw, but the present invention is not limited to a three-phase distributed winding coil. For example, the stator coil may be formed by a two-phase distributed winding coil. In addition, in the above description, the three-phase coil SC is assembled to the stator core 15 and then welded, but the present invention is not limited to this. In the case where the stator core 15 is divided, the stator core 15 can be assembled to the three-phase coil SC after the assembly and welding.

Claims

1. A stator, characterized in that: Provided in a rotating electrical machine, the stator has: a stator core formed with a plurality of slots; and a distributed winding coil including a plurality of segment coils housed in a pair of slots among the plurality of slots, wherein the plurality of segment coils are connected to each other; The distributed winding coil has the following coil structure: a plurality of parallel coils, wherein the parallel coils are formed by connecting a plurality of segment coils accommodated in the same pair of slots of the plurality of slots in parallel, and the plurality of parallel coils are connected in series. The plurality of segment coils constituting each of the parallel coils are arranged adjacent to each other in the radial direction within the slot. Each of the segment coils includes: a pair of straight portions accommodated in the pair of slots; a bent portion protruding from one end surface of the stator core and connecting the pair of straight portions; and a welded end portion protruding from the other end surface of the stator core and extending from each of the pair of straight portions. The distributed winding coil includes: a first coil end consisting of a plurality of the bent portions protruding from one end surface of the stator core; and a second coil end consisting of a plurality of the welded end portions protruding from the other end surface of the stator core. For one distributed winding coil, the number of segment coils spanning slots varies on the bent portion side constituting the first coil end, while the number of segment coils spanning slots is uniformly set on the welded end side constituting the second coil end. An inner diameter of the first coil end is smaller than an inner diameter of the second coil end.

2. The stator according to claim 1, characterized in that In the plurality of segment coils constituting each of the parallel coils, one of the pair of straight portions is arranged radially adjacent to one of the pair of slots, and the other of the pair of straight portions is arranged radially adjacent to the other of the pair of slots.

3. The stator according to claim 1, characterized in that In a pair of the parallel coils connected in series with each other, the plurality of welded end portions extending from one parallel coil and the plurality of welded end portions extending from the other parallel coil are welded to each other at one position.

4. The stator according to claim 2, characterized in that In a pair of the parallel coils connected in series with each other, the plurality of welded end portions extending from one parallel coil and the plurality of welded end portions extending from the other parallel coil are welded to each other at one position.

5. The stator according to any one of claims 1 to 4, characterized in that: An inner diameter of the first coil end is smaller than an inner diameter of the stator core.

6. The stator according to any one of claims 1 to 4, characterized in that: An inner diameter of the first coil end is smaller than an outer diameter of a rotor accommodated in the stator core.

7. The stator according to claim 5, characterized in that An inner diameter of the first coil end is smaller than an outer diameter of a rotor accommodated in the stator core.

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