Rotating electric machine

Abstract

A rotary electric machine (100) includes: a stator (10) having a stator core (11) in which a plurality of core segments (12) divided in the circumferential direction are combined in an annular shape, and a coil (16) distributedly wound around the stator core (11); and a rotor (30) which is rotatable with respect to the stator (10) and in which magnetic poles having a P number of pole pairs are disposed in a rotor core (31). Each core segment (12) has a core back (13), a plurality of teeth (14) protruding in the inner circumferential direction from the core back (13), and winding slots (15). The number of teeth (14) of each core segment (12) are equal to each other, and in a case where the number of core segments (12) is N, the relationship P < N < 2P is satisfied.

Description

Technical Field

[0001] This application relates to a rotating electric machine.

Background Art

[0002] In order to reduce the material cost of a motor, a stator core configured by combining circumferentially divided split cores, which can improve the yield of electromagnetic steel sheets, is widely used. When the stator core is finely divided in the circumferential direction, the yield of the electromagnetic steel sheets also improves. Therefore, from the perspective of reducing material costs, it is better to increase the number of divisions of the stator core. However, when adopting split cores with a large number of divisions, the number of parts increases, resulting in an increase in manufacturing costs and an increase in the difficulty of assembly. Therefore, motors adopting split cores with a small number of divisions have been studied.

[0003] A motor that reduces material costs by sharing split cores using the remaining area inside the rotor has been disclosed (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] On the other hand, when the magnetomotive force and the permeance contain the same harmonic components, an axial voltage is generated on the shaft of the rotor. In an actual machine, when combining split cores, it is difficult to prevent the generation of minute gaps between the split cores, which causes permeance harmonics and may generate an axial voltage. In the case of a motor that supports the rotor with mechanical bearings, a discharge occurs between the shaft and the bearing due to the axial voltage, causing electrical erosion of the bearing and becoming a factor of vibration and noise. Therefore, a design to reduce the axial voltage is required. Therefore, in motors employing a segmented core, it is important to pay attention to the combination of the number of rotor poles and the number of stator segments. Furthermore, even if air gaps occur between the segmented cores, the combination of rotor poles and stator segments in which no shaft voltage is generated is when the number of segments is an integer multiple of the number of poles, but this may increase torque ripple.

[0006] Patent Document 1 does not describe axial voltage and torque ripple, and the disclosed example has the problem of axial voltage caused by the air gap between the divided cores, and although no axial voltage is generated, torque ripple increases.

[0007] This application discloses technology to solve the above-mentioned problems, and aims to provide a rotating electric machine that can reduce material costs, improve manufacturability, reduce shaft voltage, and suppress torque ripple. [Means for solving the problem]

[0008] A rotating electric machine disclosed herein includes a stator having a stator core formed by combining a plurality of circumferentially divided divided cores in an annular shape, and a coil wound in a distributed winding on the stator core, In a rotating electric machine having a rotor core fixed to a shaft at the central axis of the stator, magnetic poles with a pole pair number of P arranged on the rotor core, and a rotor rotatable relative to the stator, The divided core has an arc-shaped core back and a plurality of teeth protruding inward from the core back, with winding slots between the teeth, and the number of teeth is equal. If the number of divisions of the divided core is N, then P <N<2P、 And N ≥ 6 It satisfies the following conditions. 。 [Effects of the Invention]

[0009] The rotating electric machine disclosed in this application provides a rotating electric machine that can reduce material costs, improve manufacturability, reduce shaft voltage, and suppress torque ripple. [Brief explanation of the drawing]

[0010] [Figure 1] This is a cross-sectional view of a 6-segment, 8-pole, 48-slot double V-shaped embedded magnet type motor of a rotating electric machine according to Embodiment 1. [Figure 2] This is a cross-sectional view of a segmented core constituting the stator core of a rotating electric machine according to Embodiment 1. [Figure 3] This is a perspective view of the stator core of a rotating electric machine according to Embodiment 1. [Figure 4] This is analysis data of the maximum axis voltage, with the number of divisions in the stator core of the rotating electric machine according to Embodiment 1 as a parameter. [Figure 5] This is analysis data of torque ripple amplitude, with the number of divisions in the stator core of the rotating electric machine according to Embodiment 1 as a parameter. [Figure 6] This is a cross-sectional view of a 12-segment, 8-pole, 48-slot double V-shaped embedded magnet type motor, which is a modified example of the rotating electric machine according to Embodiment 1. [Figure 7] This is a cross-sectional view of a 6-segment, 8-pole, 72-slot double V-shaped embedded magnet type motor, which is a modified example of the rotating electric machine according to Embodiment 1. [Figure 8] This is a cross-sectional view of a 12-segment, 8-pole, 96-slot double V-shaped embedded magnet type motor, which is a modified example of the rotating electric machine according to Embodiment 1. [Figure 9] This is a cross-sectional view of an 8-segment, 12-pole, 72-slot double V-shaped embedded magnet type motor, which is a modified example of the rotating electric machine according to Embodiment 1. [Figure 10] This is a cross-sectional view of a 24-segment, 16-pole, 96-slot double V-shaped embedded magnet type motor, which is a modified example of the rotating electric machine according to Embodiment 1. [Figure 11] This is a cross-sectional view of a 6-segment, 8-pole, 48-slot flat-plate magnet embedded motor, which is a modified example of the rotating electric machine according to Embodiment 1. [Figure 12] This is a cross-sectional view of a 12-segment, 8-pole, 48-slot single-V-shaped embedded magnet type motor, which is a modified example of the rotating electric machine according to Embodiment 1. [Figure 13]Cross-sectional view of a 6-split 8-pole 48-slot triple V-shaped embedded magnet motor, which is a modified example of the rotating electrical machine according to Embodiment 1. [Figure 14] Cross-sectional view of a 12-split 8-pole 48-slot ∇-shaped embedded magnet motor, which is a modified example of the rotating electrical machine according to Embodiment 1. [Figure 15] Cross-sectional view of the split core constituting the stator core of the rotating electrical machine according to Embodiment 2. [Figure 16] Cross-sectional view of a 6-split 8-pole 48-slot double V-shaped embedded magnet motor of the rotating electrical machine according to Embodiment 2. [Figure 17] Perspective view of a 30-degree rotated 4-stage stacked stator core of the rotating electrical machine according to Embodiment 3. [Figure 18] Explanatory diagram of the rolling direction and the tooth direction in the cross-sectional view of the split core of the rotating electrical machine according to Embodiment 4. [Figure 19] Explanatory diagram of the tooth numbers in the cross-sectional view of the split core of the rotating electrical machine according to Embodiment 4. [Figure 20] Explanatory diagram of the tooth direction component of the rolling direction magnetic characteristics of the teeth at the same circumferential position in each segment of the stator core in the comparative example of the rotating electrical machine according to Embodiment 4. [Figure 21] Perspective view of the stator core of the rotating electrical machine according to Embodiment 4. [Figure 22] Explanatory diagram of the tooth direction component of the rolling direction magnetic characteristics of the teeth at the same circumferential position in each segment of the stator core of the rotating electrical machine according to Embodiment 4. [Figure 23] Cross-sectional view of the split core constituting the stator core of the rotating electrical machine according to Embodiment 5. [Figure 24] Cross-sectional view of a 6-split 8-pole 48-slot double V-shaped embedded magnet motor obtained by splitting the stator core of the rotating electrical machine according to Embodiment 5 at the center of the teeth. [Figure 25] Perspective view of a rotated-by-30-degree 6-stage stacked stator core of the rotating electrical machine according to Embodiment 5. [Figure 26]Cross-sectional view of a 12-split 8-pole 48-slot double V-shaped embedded magnet type motor divided at the center of the teeth, which is a modification of the rotating electrical machine according to Embodiment 5. [Figure 27] Cross-sectional view of the split core constituting the stator core of the rotating electrical machine according to Embodiment 6. [Figure 28] Cross-sectional view of a 4-split 6-pole 54-slot double V-shaped embedded magnet type motor divided by core back splitting and tooth splitting of the rotating electrical machine according to Embodiment 6. [Figure 29] Perspective view of a 45-degree rotated two-layer stacked stator core of the rotating electrical machine according to Embodiment 6.

Embodiments for Carrying Out the Invention

[0011] Embodiment 1. Embodiment 1 has a stator having a stator core formed by annularly combining a plurality of split cores divided in the circumferential direction, and a coil wound around the stator core by distributed winding, and a rotor core fixed to a shaft on the central axis of the stator. A magnetic pole with a pole pair number P is arranged on the rotor core, and in a rotating electrical machine provided with a rotor rotatable with respect to the stator, the split core has an arcuate core back and a plurality of teeth protruding from the core back in the inner circumferential direction. There are winding slots between the teeth, the number of teeth is equal, and if the number of splits of the split core is N, it satisfies P < N < 2P or 2P < N < 4P.

[0012] Hereinafter, the rotating electrical machine according to Embodiment 1 will be described based on FIG. 1 which is a cross-sectional view of a 6-split 8-pole 48-slot double V-shaped embedded magnet type distributed winding motor, FIG. 2 which is a cross-sectional view of the split core constituting the stator core, FIG. 3 which is a perspective view of the stator core, FIG. 4 which is analytical data of the maximum value of the axial voltage with the number of splits of the stator core as a parameter, FIG. 5 which is analytical data of the torque ripple amplitude with the number of splits of the stator core as a parameter, and FIGS. 6 to 14 which are cross-sectional views of an embedded magnet type distributed winding motor as a modification of the rotating electrical machine. In each figure, the same part or corresponding part is denoted by the same reference numeral, and duplicate explanations are omitted.

[0013] In the following explanation, the direction in the axis of rotation is defined as the axial direction (Z), the direction towards the center of the axis of rotation (the direction from the outer circumference of the stator toward the center of the axis of rotation) is defined as the radial direction (R), and the direction along the rotational direction around the axis of rotation is defined as the circumferential direction (P), and these will be indicated in the drawings as appropriate. Furthermore, since this application assumes an embedded magnet type distributed winding motor as the rotating electric machine, the embedded magnet type distributed winding motor will be appropriately referred to as an embedded magnet type motor in the description.

[0014] First, the overall structure of the rotating electric machine 100 of Embodiment 1 will be described based on Figure 1, a cross-sectional view of the rotating electric machine 100 taken from a plane perpendicular to the axial direction of the rotating electric machine 100; Figure 2, a cross-sectional view of the segmented cores constituting the stator core; and Figure 3, a perspective view of the stator core. The rotating electric machine 100 consists of a stator 10 and a rotor 30 that is coaxially arranged on the inner circumference side of the stator 10 and is rotatable relative to the stator 10. The stator 10 comprises a stator core 11, teeth 14, and coils 16. The stator core 11 is composed of a divided core 12 with a number of divisions N (in Figure 1, the number of divisions N is 6), which will be described later, and comprises a core back 13, teeth 14, and winding slots 15. The rotor 30 comprises a rotor core 31, a shaft 32, and a permanent magnet 33.

[0015] First, the basic segmented core 12 of the stator 10 will be explained based on Figure 2. The segmented core 12 constituting the stator core 11 of the rotating electric machine 100 in Embodiment 1 is constructed by laminating multiple electromagnetic steel sheets and consists of multiple teeth 14 that protrude inward from the central axis from the arc-shaped core back 13, and winding slots 15 which are the areas between adjacent teeth 14. The segmented core 12 is divided from the circumferential center of the winding slots 15 to the core back 13 (core back division). There are eight teeth 14 arranged in the circumferential direction, and the arc angle of the segmented core 12 is 60 degrees.

[0016] Returning to Figure 1, let's explain the rotating electric machine 100. The stator core 11 is constructed by arranging six segmented cores 12, as described in Figure 2, in a ring shape. Each segmented core 12 has the same number of teeth 14, and there are 48 teeth 14 evenly distributed in the circumferential direction. In addition, in the stator core 11 of Embodiment 1, a minute gap 21 is formed between each segmented core 12 in the contact area formed between each segmented core 12 that are arranged adjacent to each other. In the stator core 11 of Embodiment 1, the gap 21 is formed at most locations in each contact area between the segmented cores 12, within the range of manufacturing variations. Furthermore, the width and size of the gap 21 are formed differently at each contact area between the segmented cores 12.

[0017] Furthermore, each winding slot 15 houses a coil 16, and each coil 16 is connected in series with a coil 16 housed in a winding slot 15 six positions away in the circumferential direction.

[0018] The rotor 30 consists of a shaft 32 located on the central axis of the stator 10, an annular rotor core 31 fixed to the shaft 32, and permanent magnets 33 arranged in two layers in a V-shape in a magnet slot 34 provided in the rotor core 31 so that there are eight magnetic poles (double V-shaped embedded magnet type).

[0019] As shown in Figure 3, the stator core 11 is configured such that the division positions are the same in all axial cross-sections. In this way, it is configured as an 8-pole, 48-slot distributed winding motor using a 6-segment core.

[0020] Next, we will explain the shaft voltage and torque ripple generated in rotating electric machines and methods for suppressing them, using the electromagnetic field analysis results shown in Figures 4 and 5. Figure 4 shows the analysis results of the maximum axial voltage when the stator core 11 of an 8-pole, 48-slot distributed winding motor is equally divided by the core back 13 (0 divisions, 2 divisions, 3 divisions, 4 divisions, 6 divisions, 8 divisions, 12 divisions, 16 divisions, 24 divisions, 48 ​​divisions), and a 25 μm gap 21 is created between each divided core 12. However, the maximum axial voltage is normalized to the maximum axial voltage when the core is divided into 6 divisions. Figure 5 shows the analysis results of the torque ripple amplitude when the stator core 11 of an 8-pole, 48-slot distributed winding motor is equally divided by the core back 13 (0 divisions, 2 divisions, 3 divisions, 4 divisions, 6 divisions, 8 divisions, 12 divisions, 16 divisions, 24 divisions, 48 ​​divisions), and a 25 μm gap 21 is generated between each divided core 12. However, the torque ripple amplitude is normalized to the torque ripple amplitude when it is divided into 6 divisions.

[0021] One of the problems addressed by this invention is axial voltage, which is known to occur when the same component exists in the magnetomotive force harmonics and permeance harmonics. In a motor in which a stator core 11 is made up of circumferentially divided segmented cores 12, a small gap 21 is generated between adjacent segmented cores, and this is the cause of permeance harmonics. In an 8-pole, 48-slot embedded magnet motor, when air gaps 21 occur between each of the divided cores 12, shaft voltage is generated when the core is divided into 2, 3, 4, 6, and 12 sections. Furthermore, in the 2 and 4 sections, the shaft voltage is expected to be larger because the permeance harmonics have the same component as all of the magnetomotive force harmonics.

[0022] As shown in Figure 4, an axis voltage is generated when the division is 2, 3, 4, 6, and 12. In particular, when the division is 2 and 4, a permeance harmonic with the same component as all magnetomotive force harmonics is present, so it was confirmed that the axis voltage becomes larger.

[0023] Furthermore, when the stator core 11 is divided into integer multiples of the number of poles, no shaft voltage is generated. However, if a number of divided cores 12 that are integer multiples of the number of poles is used, and air gaps 21 are created between the divided cores 12, there is a concern that the torque ripple will increase.

[0024] As shown in Figure 5, the torque ripple of the 8-segment embedded magnet motor is increased by approximately 5% compared to the 6-segment embedded magnet motor, which is the rotating electric machine 100 of Embodiment 1. Furthermore, the torque ripple is also increased compared to the 6-segment embedded magnet motor in the 16, 24, and 48-segment embedded magnet motors, which are integer multiples of the number of poles.

[0025] From the above results, in the 8-pole 48-slot embedded magnet type motor, the number of divisions suitable for both low shaft voltage and low torque ripple is determined to be 3, 6, and 12. Those that can fully exhibit the effect of reducing the material cost of the divided core 12 are the 6-pole motor of Embodiment 1 with a number of divisions larger than the number of pole pairs P and the 12-pole motor as shown in FIG. 6 to be described later. These numbers of divisions satisfy the relationship of P < N < 2P (Condition A) or 2P < N < 4P (Condition B).

[0026] As described above, in Embodiment 1, by forming the divided core 12 of the rotating electrical machine 100, the yield of the electromagnetic steel sheet of the divided core 12 is improved, so that the material cost can be reduced. Furthermore, by adopting a divided core 12 with a small number of divisions, the number of parts can be reduced and the manufacturability can be improved. And because the relationship between the number of pole pairs and the number of divisions satisfies P < N < 2P (Condition A) or 2P < N < 4P (Condition B), it is possible to reduce the shaft voltage generated by the combination of the number of poles and the number of divisions of the stator core 11, and to suppress the torque ripple generated by the number of poles and the number of divisions of the stator core 11. In addition, due to the core-back divided structure, the distortion of the teeth 14 can be suppressed, the manufacturing distortion of the entire embedded magnet type motor can be reduced, and the motor loss can be reduced.

[0027] Here, the relationship between the number of divisions N of the divided core 12 and the number S of winding slots 15 will be described. The circumferential number of divisions N of the stator core 11 is set to be a divisor of S, so that the shapes of all the divided cores 12 constituting the stator core 11 can be made the same, and thus the manufacturing cost of the divided core 12 can be reduced.

[0028] Next, regarding the modified example of the 6-pole 8-pole 48-slot double V-shaped embedded magnet type distributed winding motor described in Embodiment 1, the relationship with P < N < 2P (Condition A) and 2P < N < 4P (Condition B) will also be described. In each figure, for the purpose of distinguishing from the rotating electrical machine (the 6-pole 8-pole 48-slot double V-shaped embedded magnet type distributed winding motor) 100 in FIG. 2, the reference numerals are 101 and the like.

[0029] Figure 6 is a cross-sectional view of an 8-pole 48-slot double-V embedded magnet type distributed winding motor (rotating electrical machine 101) in which the stator core 11 is circumferentially equally divided into 12 parts by the core back 13. In this example, 2P < N < 4P (Condition B) is satisfied. Figure 7 is a cross-sectional view of an 8-pole 72-slot double-V embedded magnet type distributed winding motor (rotating electrical machine 102) in which the stator core 11 is circumferentially equally divided into 6 parts by the core back 13. In this example, P < N < 2P (Condition A) is satisfied. Figure 8 is a cross-sectional view of an 8-pole 96-slot double-V embedded magnet type distributed winding motor (rotating electrical machine 103) in which the stator core 11 is circumferentially equally divided into 12 parts by the core back 13. In this example, 2P < N < 4P (Condition B) is satisfied. Figure 9 is a cross-sectional view of a 12-pole 72-slot double-V embedded magnet type distributed winding motor (rotating electrical machine 104) in which the stator core 11 is circumferentially equally divided into 8 parts by the core back 13. In this example, P < N < 2P (Condition A) is satisfied. Figure 10 is a cross-sectional view of a 16-pole 96-slot double-V embedded magnet type distributed winding motor (rotating electrical machine 105) in which the stator core 11 is circumferentially equally divided into 24 parts by the core back 13. In this example, 2P < N < 4P (Condition B) is satisfied.

[0030] Figure 11 is a cross-sectional view of an 8-pole 48-slot flat magnet embedded type distributed winding motor (rotating electrical machine 106) in which the stator core 11 is circumferentially equally divided into 6 parts by the core back 13. In this example, P < N < 2P (Condition A) is satisfied. Figure 12 is a cross-sectional view of an 8-pole 48-slot single-V embedded magnet type distributed winding motor (rotating electrical machine 107) in which the stator core 11 is circumferentially equally divided into 12 parts by the core back 13. In this example, 2P < N < 4P (Condition B) is satisfied. Figure 13 is a cross-sectional view of an 8-pole 48-slot triple-V embedded magnet type distributed winding motor (rotating electrical machine 108) in which the stator core 11 is circumferentially equally divided into 6 parts by the core back 13. In this example, P < N < 2P (Condition A) is satisfied. Figure 14 is a cross-sectional view of an 8-pole 48-slot ∇-type embedded magnet type distributed winding motor (rotating electrical machine 109) in which the stator core 11 is circumferentially equally divided into 12 parts by the core back 13. In this example, 2P < N < 4P (Condition B) is satisfied.

[0031] Here, the embedded magnet type distributed winding motors in FIGS. 6 to 14 of the modified examples will be summarized. FIG. 6 shows an 8-pole 48-slot distributed winding motor using a 12-segment core, which satisfies 2P < N < 4P (Condition B) and exhibits the same effects as the rotating electrical machine of Embodiment 1. Also, as shown in FIGS. 7 to 10, even when the combination of the number of pole pairs and the number of slots is different, if the relationship between the number of pole pairs and the number of segments satisfies P < N < 2P (Condition A) or 2P < N < 4P (Condition B), the same effects are achieved. Also, as shown in FIGS. 11 to 14, even with different embedded magnet type rotor structures, if the above relationship between the number of pole pairs and the number of segments satisfies P < N < 2P (Condition A) or 2P < N < 4P (Condition B), the same effects as the rotating electrical machine of Embodiment 1 are achieved. Furthermore, although not shown, in the case of a surface-mounted type and a winding field magnetic structure as well, if the relationship between the number of pole pairs and the number of segments satisfies P < N < 2P (Condition A) or 2P < N < 4P (Condition B), the same effects as the rotating electrical machine of Embodiment 1 can be obtained.

[0032] Also, the air gaps 21 formed at the contact portions between the adjacent segment cores 12, which were described as the configuration of the stator core 11 in Embodiment 1, when the widths and sizes of each are different from each other, by setting the number of segments to a small number of segments that satisfies P < N < 2P (Condition A), the permeance harmonics generated by the variation of the air gaps 21 can be reduced, and the shaft voltage can be more effectively reduced.

[0033] As described above, the rotating electrical machine of Embodiment 1 includes a stator having a stator core formed by annularly combining a plurality of divided cores divided in the circumferential direction, and coils wound around the stator core in a distributed winding manner, and a rotor core fixed to a shaft at the central axis of the stator. A magnetic pole with a pole pair number P is arranged on the rotor core, and a rotor rotatable with respect to the stator is provided. The divided core has an arc-shaped core back and a plurality of teeth protruding from the core back in the inner circumferential direction. There are winding slots between the teeth, the number of teeth is equal, and when the number of divisions of the divided core is N, it satisfies P < N < 2P or 2P < N < 4P. Therefore, in Embodiment 1, a rotating electrical machine can be obtained that reduces material costs, improves manufacturability, reduces shaft voltage, and suppresses torque ripple.

[0034] Embodiment 2. In Embodiment 2, fitting convex portions and concave portions are provided at the abutting portions of the divided cores, and grooves are provided on the outer peripheral portions.

[0035] Regarding the rotating electrical machine of Embodiment 2, based on FIG. 15 which is a cross-sectional view of the divided core constituting the stator core, and FIG. 16 which is a cross-sectional view of a 6-pole 8-pole 48-slot double V-shaped embedded magnet type motor, the differences from Embodiment 1 will be mainly described. In FIGS. 15 and 16 of Embodiment 2, the same or corresponding parts as those in Embodiment 1 are denoted by the same reference numerals. In order to distinguish from the rotating electrical machine 100 and the divided core 12 of Embodiment 1, they are denoted as the rotating electrical machine 200 and the divided core 212.

[0036] As shown in FIG. 15, the divided core 212 constituting the stator core 11 of the rotating electrical machine 200 in Embodiment 2 is formed by laminating a plurality of electromagnetic steel sheets, and includes a plurality of teeth 14 protruding from the core back 13 on the arc in the inner circumferential direction toward the central axis, and winding slots 15 which are regions between adjacent teeth 14. The divided core 212 is divided from the circumferential center of the winding slot 15 to the core back 13 (core back division). A convex portion 23 is provided on one side of the contact portion of the divided core 212, and a concave portion 24 is provided on the other side, and a groove 22 is provided on the outer circumference. Eight teeth 14 are arranged in the circumferential direction, and the arc angle of the divided core 212 is 60 degrees.

[0037] In Figure 16, the embedded magnet type motor, which is the rotating electric machine 200 in Embodiment 2, consists of a stator 10 and a rotor 30 that is coaxially arranged on the inner circumference side of the stator 10 and is rotatable relative to the stator 10. The stator 10 comprises a stator core 11, teeth 14, and coils 16. The stator core 11 is constructed by arranging six segmented cores 212, as described in Figure 15, in a ring shape, and the teeth 14 consist of 48 teeth evenly spaced in the circumferential direction. Coil 16 is connected in series with the coil 16 housed in the winding slot 15 six spaces away in the circumferential direction. The rest of the configuration is the same as in Embodiment 1.

[0038] Each of the protrusions 23 and recesses 24 of the divided core 212 is assembled to fit together with the adjacent divided core 212, and is fixed by welding in the groove 22 on the outer circumference of the contact portion. Furthermore, in the stator core 11 of the second embodiment, the outer periphery of the contact portion formed between each adjacent segmented core 212 is joined together without gaps by welding.

[0039] On the other hand, a minute gap 21 is formed on the inner circumference side of the contact portion between the divided cores 212. In the stator core 11 of Embodiment 2, within the range of manufacturing variations, this gap 21 is formed at most locations of each contact area between the segmented cores 212, and the width and size of the gap 21 differ from one another at each contact area between the segmented cores 212. Particularly in the case of a structure where the outer periphery is joined by welding, the depth of penetration in the radial direction of the joining area by welding varies relatively greatly during manufacturing. Therefore, as described above, the radial width of the minute voids 21 remaining on the inner peripheral side varies relatively greatly.

[0040] Thus, by adopting the split core 212, the yield of the electromagnetic steel sheet is improved, and the material cost can be reduced. Further, by adopting a split core 212 with a small number of splits, the number of parts can be reduced and the productivity can be improved. And since the relationship between the number of pole pairs and the number of splits satisfies P < N < 2P (Condition A) or 2P < N < 4P (Condition B), the axial voltage generated by the combination of the number of poles and the number of splits of the stator core 11 can be reduced. Also, the torque ripple generated by the number of poles and the number of splits of the stator core 11 can be suppressed.

[0041] By assembling the split cores 212 using the convex portions 23 and concave portions 24 of the contact portion, the positioning accuracy of the split cores 212 can be improved and the productivity can be improved. Also, by welding the outer peripheral side of the contact portion between the split cores 212, the rigidity of the stator core 11 can be increased. [[ID=?]] Also, by using the groove 22 as a welding groove and joining between the split cores 212, the welding bead does not protrude from the outer periphery of the stator core 11, and the unevenness on the outer periphery of the stator core 11 can be eliminated. And when press-fitting into the housing, the assembly of the stator 10 becomes easy. Also, due to the structure in which the winding slot 15 is divided from the circumferential center portion to the core back 13 (core back division), the distortion of the teeth 14 can be suppressed, the manufacturing distortion of the entire embedded magnet type motor can be reduced, and the motor loss can be reduced.

[0042] Also, the circumferential division number N of the stator core 11 is a divisor of the number S of the winding slots 15, and since the shapes of all the split cores 12 constituting the stator core 11 can be made the same, the manufacturing cost of the split cores 212 can be reduced.

[0043] On the one hand, as in the second embodiment, the groove 22 on the outer peripheral portion of the contact portion of the split core 212 causes a permeance harmonic, resulting in the generation of an axial voltage. And it is considered that the axial voltage increases due to the occurrence of shape variations in the groove 22. However, by applying the number of splits that satisfies P < N < 2P (condition A) or 2P < N < 4P (condition B) described in the first embodiment, the axial voltage can be more effectively reduced.

[0044] Also, although not shown, even when the combination of the number of pole pairs and the number of slots is different, if the relationship between the number of pole pairs and the number of splits satisfies P < N < 2P (condition A) or 2P < N < 4P (condition B), the same effect can be achieved.

[0045] Also, although not shown, even with different rotor structures, if the relationship between the number of pole pairs and the number of splits satisfies P < N < 2P (condition A) or 2P < N < 4P (condition B), the same effect can be achieved.

[0046] Also, as the structure of the stator core 11 in the second embodiment, when the gaps 21 formed at the contact portions between the adjacent split cores 212 have different widths and sizes from each other, by setting the number of splits to a small number of splits that satisfies P < N < 2P (condition A), the permeance harmonics generated by the variations in the gaps 21 can be reduced, and the axial voltage can be more effectively reduced.

[0047] In the second embodiment, as a suitable example, the fixing structure between the adjacent split cores 212 was described as a structure that is reinforced and fixed by welding. However, as the fixing structure between the adjacent split cores 212, it is also possible to adopt a structure in which an annular frame is externally inserted on the outer periphery of the stator core 11 that is annularly joined only by the fitting structure of the convex portions 23 and concave portions 24 of each of the split cores 212. In this case, the joining by welding can be omitted. Also, it is possible to adopt a structure in which an adhesive such as resin is arranged between the adjacent split cores 212 to adhere and fix them to each other.

[0048] Even when such fixed structures are used, especially when a gap 21 is formed at the abutting portion between adjacent split cores 212 and even when their respective widths and sizes are different from each other, if the relationship between the number of pole pairs and the number of splits satisfies P < N < 2P (Condition A) or 2P < N < 4P (Condition B), the effects described in Embodiment 1 can be obtained.

[0049] As described above, the rotating electrical machine of Embodiment 2 has a fitting convex portion and concave portion at the abutting portion of the split core, and a groove provided on the outer peripheral portion, and the relationship between the number of pole pairs and the number of splits satisfies P < N < 2P (Condition A) or 2P < N < 4P (Condition B). Therefore, the rotating electrical machine of Embodiment 2 can reduce the material cost, improve the manufacturability, reduce the shaft voltage, and suppress the torque ripple.

[0050] Embodiment 3. In Embodiment 3, the stator core is divided into four parts in the axial direction and is rotated by 30 degrees and laminated.

[0051] Regarding the rotating electrical machine of Embodiment 3, based on FIG. 17 which is a perspective view of a 30-degree rotated four-stage laminated stator core, the differences from Embodiment 1 will be mainly described. In FIG. 17 of Embodiment 3, the same or corresponding parts as those in Embodiment 1 are denoted by the same reference numerals. Note that in order to distinguish it from Embodiment 1, it is referred to as the rotating electrical machine 300.

[0052] The stator core 11 of the rotating electrical machine 300 of Embodiment 3 is divided into four segments in the axial direction. In FIG. 17, segment A is denoted as SGA, segment B as SGB, segment C as SGC, and segment D as SGD. With the rotation axis of the rotor 30 as the axis, segment B is rotated by a mechanical angle of 30 degrees with respect to segment A, segment C is rotated by a mechanical angle of 30 degrees with respect to segment B, segment D is rotated by a mechanical angle of 30 degrees with respect to segment C, and segments A to D are stacked in the axial direction. Furthermore, each segment of the stator core 11 is composed of a divided core 12 with 6 divisions. The other structures are the same as those of the rotating electric machine of Embodiment 1.

[0053] This configuration enhances the rigidity of the stator core 11, which is formed by combining the segmented cores 12, in addition to the effects of the rotating electric machine in Embodiment 1, thereby improving vibration resistance and strength. Furthermore, since the circumferential positions of the winding slots 15 are the same in each segment, insertion of the coils 16 becomes easier, improving manufacturability. Furthermore, the effects of magnetic anisotropy in the direction perpendicular to the rolling direction of the teeth 14 of the stator core 11, which will be explained later, can be reduced, thereby reducing losses, shaft voltage, and torque ripple in the embedded magnet type motor.

[0054] The stator core 11 is generalized by setting N (an integer) as the number of circumferential divisions, t (an integer greater than or equal to 2) as the number of axial divisions, n as an integer, and k as an integer satisfying k = t / n. If the segments of the stator core 11, which are divided into t segments in the axial direction, are rotated by a mechanical angle of 360 / N / k degrees around the rotation axis of the rotor 30 and stacked in the axial direction relative to adjacent segments, the same effect as in Embodiment 3 can be achieved.

[0055] Furthermore, this can be generalized using the number S of winding slots 15 in the stator core 11. If the stator core 11, which is divided into t segments in the axial direction, is rotated by a mechanical angle (360 / S) × n degrees relative to the adjacent segment in the axial direction, with respect to the rotation axis of the rotor 30, and stacked in the axial direction, the same effect as in Embodiment 3 can be achieved.

[0056] Furthermore, as in Embodiment 2, by assembling the segmented cores 12 with protrusions and recesses at the contact points, the positioning accuracy of the segmented cores 12 can be improved, and manufacturability can be enhanced. In addition, by welding the outer circumference of the contact points of the segmented cores 12, the rigidity of the stator core 11 can be further increased. Moreover, by welding in the grooves on the outer circumference of the segmented cores 12, the protrusions and recesses on the outer circumference of the stator core 11 can be eliminated, making it easier to assemble the stator 10 when inserting the stator core 11 into a housing or the like.

[0057] As described above, the rotating electric machine of Embodiment 3 is constructed by dividing the stator core into four sections in the axial direction and rotating and accumulating them by 30 degrees. Therefore, the rotating electric machine of Embodiment 3 can reduce material costs, improve manufacturability, reduce shaft voltage, and suppress torque ripple. Furthermore, it can increase the rigidity of the stator core 11, improve vibration resistance and strength, and reduce the influence of magnetic anisotropy of the teeth 14 of the stator core 11 in the direction perpendicular to the rolling direction.

[0058] Embodiment 4. Embodiment 4 balances the magnetic anisotropy of the stator core teeth across the entire embedded magnet type motor.

[0059] Regarding the rotating electric machine of Embodiment 4, the differences from Embodiment 1 will be explained based on Figure 18, which is an explanatory diagram of the rolling direction and tooth direction in the cross-sectional view of the divided core; Figure 19, which is an explanatory diagram of the tooth number in the cross-sectional view of the divided core; Figure 20, which is an explanatory diagram of the tooth direction component of the rolling direction magnetic properties of teeth at the same circumferential position in each segment of the stator core in the comparative example; Figure 21, which is a perspective view of the stator core; and Figure 22, which is an explanatory diagram of the tooth direction component of the rolling direction magnetic properties of teeth at the same circumferential position in each segment of the stator core. In Figures 18, 19, and 21 of Embodiment 4, parts that are the same as or corresponding to those in Embodiment 1 are denoted by the same reference numerals. In order to distinguish it from the rotating electric machine 100 of Embodiment 1, it is referred to as the rotating electric machine 400.

[0060] In Figure 18, the rolling direction is denoted as "RD" and the teething direction as "TD". The angle between the rolling direction vector and the teething direction vector is denoted as θ. The electrical steel sheets that make up the segmented core 12 may have different magnetic properties in the rolling direction and in the direction perpendicular to it. As shown in Figure 18, the teeth direction, which is the direction in which the teeth 14 face the center of rotation, and the rolling direction do not coincide for all teeth 14. To make the following explanation easier to understand, tooth numbers are shown in Figure 19. The teeth of the divided core 12 are numbered in a counterclockwise direction around the circumference. Teeth numbers 1 through 8 are labeled TN1, TN2, TN3, TN4, TN5, TN6, TN7, and TN8.

[0061] When the angle between the rolling direction vector and the tooth direction vector is θ, the tooth-direction component of the rolling direction magnetic properties of each tooth 14 is determined by the cosine of the rolling direction vector. Then, when the segments of the stator core 11 in four axial stages are combined, the sum of the tooth-direction components of the rolling direction magnetic properties of the teeth 14 at the same circumferential position is taken.

[0062] First, as a comparative example, Figure 20 illustrates the case where the stator core 11 of the rotating electric machine 300 of Embodiment 3, as described in Figure 17, is divided into four stages, and each segment is shifted at a 30-degree angle. Figure 20 shows the results of calculating the tooth-direction component of the rolling direction magnetic properties for each tooth number 1 to 8 of the stator core 11 at the same circumferential position on each segment. When the sum of the tooth-direction components of the rolling direction magnetic properties of teeth 14 at the same circumferential position is taken, there are two types: 3.79 and 3.86. Therefore, it can be seen that the stator core 11 described in Figure 17 has different magnetic properties in the tooth direction. As a result, the magnetic anisotropy in the direction perpendicular to the rolling direction of the teeth 14 of the stator core 11 may cause increased losses in the embedded magnet type motor, generation of shaft voltage, and increased torque ripple.

[0063] Therefore, as shown in Figure 21, the stator core 11 of the rotating electric machine 400 in Embodiment 4 is divided into four segments in the axial direction, and each segment is rotated by a mechanical angle of 15 degrees. That is, with the rotation axis of the rotor 30 as the axis, segment B is rotated by a mechanical angle of 15 degrees relative to segment A, segment C is rotated by a mechanical angle of 15 degrees relative to segment B, and segment D is rotated by a mechanical angle of 15 degrees relative to segment C, so that segments A to D are stacked in the axial direction. In addition, each segment of the stator core 11 is composed of a divided core 12 with 6 divisions. The other structures are the same as in Embodiment 1.

[0064] Figure 22 shows the tooth-direction component of the rolling direction magnetic properties of teeth 1 to 8 of the stator core 11 of the rotating electric machine 400 of Embodiment 4 shown in Figure 21, calculated at the same circumferential position of each segment. When the segments of the four-stage stator core 11 are combined, the sum of the tooth-direction components is always 3.82, indicating that they are balanced.

[0065] Therefore, by adopting the configuration of Embodiment 4, in addition to the effects of the rotating electric machine of Embodiment 1, the magnetic anisotropy of all teeth 14 of the stator core 11 in the direction perpendicular to the rolling direction can be balanced across the entire embedded magnet type motor. As a result, the losses, shaft voltage, and torque ripple of the embedded magnet motor can be reduced. Furthermore, the rigidity of the stator core 11, which is formed by combining the segmented cores 12, can be increased, improving vibration resistance and strength. In addition, since the circumferential position of the winding slots 15 is the same in each segment, insertion of the coils 16 becomes easier, improving manufacturability.

[0066] Here, we generalize by setting N to the number of circumferential divisions of the stator core 11, t to the number of axial divisions of the stator core 11, and n to an integer, where t is a number satisfying t=4n. A similar effect can be achieved by rotating each segment of the stator core 11, which is divided into t segments in the axial direction, by a mechanical angle of 360 / N / 4 degrees around the rotation axis of the rotor 30, relative to the adjacent segment in the axial direction, and stacking them in t layers in the axial direction.

[0067] Furthermore, as described in Embodiment 2, by assembling the segmented cores 12 with protrusions and recesses at the contact points, the positioning accuracy of the segmented cores 12 can be improved, and manufacturability can be enhanced. In addition, the rigidity of the stator core 11 can be further increased by welding the outer circumference of the contact points. Moreover, by welding the grooves on the outer circumference of the contact points of the segmented cores 12, the protrusions and recesses on the outer circumference of the stator core 11 can be eliminated, making it easier to assemble the stator 10 when inserting the stator core 11 into a housing or the like.

[0068] As described above, the rotating electric machine of Embodiment 4 balances the magnetic anisotropy of the stator core teeth across the entire embedded magnet type motor. Therefore, the rotating electric machine of Embodiment 4 can reduce material costs, improve manufacturability, reduce shaft voltage, and suppress torque ripple. Furthermore, it can balance the influence of magnetic anisotropy in the direction perpendicular to the rolling direction of the teeth 14 of the stator core 11, thereby increasing the rigidity of the stator core 11 and improving vibration resistance and strength.

[0069] Embodiment 5. Embodiment 5 is a tooth-partitioned design in which the divided core is divided at the center of the teeth.

[0070] Regarding the rotating electric machine of Embodiment 5, the differences from Embodiment 1 will be explained based on Figure 23, a cross-sectional view of the divided core constituting the stator core; Figure 24, a cross-sectional view of a 6-divided, 8-pole, 48-slot double V-shaped embedded magnet type motor in which the stator core is divided at the center of the teeth; Figure 25, a perspective view of a 30-degree rotating, 6-stage shifted stator core; and Figure 26, a modified example of a 12-divided, 8-pole, 48-slot double V-shaped embedded magnet type motor in which the stator core is divided at the center of the teeth. In Figures 23 to 26 of Embodiment 5, parts that are the same as or corresponding to those in Embodiment 1 are denoted by the same reference numerals. In order to distinguish them from the rotating electric machine 100 and divided core 12 of Embodiment 1, these are referred to as the rotating electric machine 500 and the divided core 512.

[0071] As shown in Figure 23, the segmented core 512 constituting the stator core 11 of the rotating electric machine 500 in Embodiment 5 is constructed by laminating multiple electromagnetic steel sheets and consists of multiple teeth 14 that protrude inward from the arc-shaped core back 13 toward the central axis, and winding slots 15 which are the regions between adjacent teeth 14. The segmented core 512 is divided from the circumferential center of the teeth 14 toward the core back 13 (tooth segmentation). Each segmented core 512 has eight teeth 14 arranged in the circumferential direction, and the arc angle of the segmented core 512 is 60 degrees.

[0072] As shown in Figure 24, the rotating electric machine 500 of Embodiment 5 has a stator core 11 composed of the divided core 512 described in Figure 23, and the other configurations are the same as in Embodiment 1.

[0073] As shown in Figure 25, the stator core 11 is divided into six segments (SGA, SGB, SGC, SGD, SGE, SGF) in the axial direction. Each segment of the stator core 11 is stacked in the axial direction, rotated by a mechanical angle of 30 degrees around the rotation axis of the rotor 30 relative to adjacent segments in the axial direction. In the figure, segment E is labeled as SGE and segment F is labeled as SGF.

[0074] This configuration improves the yield of electrical steel sheets due to the segmented core 512, thereby reducing material costs. Furthermore, by using a segmented core 512 with a small number of segments, the number of parts can be reduced, improving manufacturability. Furthermore, the shaft voltage generated by the combination of the number of poles and the number of divisions of the stator core 11 can be reduced. In addition, torque ripple generated by the combination of the number of poles and the number of divisions of the stator core 11 can also be suppressed.

[0075] Also, in the case of tooth segmentation, since the segmentation position is outside the winding slot 15, distortion is less likely to occur in the winding slot 15, insertion of the coil 16 becomes easier, and manufacturing productivity can be improved.

[0076] Also, the number of circumferential divisions N of the stator core 11 is a divisor of the number S of winding slots 15, and since the shapes of all the divided cores 12 constituting the stator core are the same, the manufacturing cost of the divided core 512 can be reduced.

[0077] Also, Fig. 26 shows an 8-pole 48-slot distributed winding motor using a 12-divided core. When the number of pole pairs is P and the number of equal circumferential divisions of the stator core 11 is N, for a rotating electrical machine that satisfies P < N < 2P (Condition A) or 2P < N < 4P (Condition B), the same effects as those of Embodiment 5 can be obtained. In Fig. 26, in order to distinguish it from the rotating electrical machine 500 of Figs. 24 and 25, it is designated as the rotating electrical machine 501.

[0078] Also, even when the combination of the number of pole pairs and the number of slots is different, the same effects can be obtained as long as the relationship between the number of pole pairs and the number of divisions satisfies P < N < 2P (Condition A) or 2P < N < 4P (Condition B). Also, even for different rotor structures, the same effects can be obtained as long as the above relationship between the number of pole pairs and the number of divisions (P < N < 2P (Condition A) or 2P < N < 4P (Condition B)) is satisfied.

[0079] Also, as in Embodiment 2, by assembling the divided cores 512 with concavo-convex portions arranged at the abutting portions, the positioning accuracy of the divided cores 12 can be improved, and manufacturing productivity can be improved. Then, by welding the outer peripheral portions of the abutting portions of the divided cores 512, the rigidity of the stator core 11 can be further increased. Furthermore, by performing welding in the grooves of the outer peripheral portions of the divided cores 512, the unevenness on the outer periphery of the stator core 11 can be eliminated, and when the stator core 11 is inserted into a housing or the like, the assembly of the stator 10 becomes easier. At this time, due to the presence of grooves on the outer peripheral portion of the abutting portion of the split core 512, it becomes a factor of the permeance harmonic, and an axial voltage is generated. And it is considered that the axial voltage increases due to the occurrence of shape variations in the grooves. However, by applying a split number that satisfies the relationship between the number of pole pairs and the split number of P < N < 2P (condition A) or 2P < N < 4P (condition B), the axial voltage can be reduced more effectively.

[0080] Also, when the gaps 21 formed in the abutting portions between the adjacent split cores 512, which were described as the configuration of the stator core 11 in Embodiment 5, are formed with different widths and sizes for each, by setting the split number to a small split number that satisfies P < N < 2P (condition A), it is possible to reduce the permeance harmonics generated by the variations in the gaps 21 and more effectively reduce the axial voltage.

[0081] And by adopting a structure stacked with a convolution of 30 degrees of mechanical angle, the rigidity of the stator core 11 combined with the split cores 512 can be enhanced, and the vibration resistance and strength can be improved. Also, since the circumferential position of the winding slot 15 is the same in each segment, the insertion of the coil 16 becomes easy, and the manufacturability is improved. And it is possible to reduce the influence of magnetic anisotropy in the direction perpendicular to the rolling direction of the teeth 14 of the stator core 11, and reduce the loss, torque ripple, and axial voltage of the embedded magnet type motor.

[0082] Also, when the circumferential split number of the stator core 11 is N, the axial split number of the stator core 11 is t, n is an integer, and k is a number that satisfies k = t / n, if the segments of the stator core 11 axially split into t pieces are rotated by 360 / N / k degrees of mechanical angle with respect to the adjacent segment in the axial direction and stacked in t stages in the axial direction, the same effect as in Embodiment 3 can be obtained.

[0083] Also, when t is a number that satisfies t = 4n, if the segments of the stator core 11 axially split into t pieces are rotated by 360 / N / 4 degrees of mechanical angle with respect to the adjacent segment in the axial direction and stacked in t stages in the axial direction, the same effect as in Embodiment 4 can be obtained.

[0084] As described above, the rotating electric machine of Embodiment 5 is a tooth-splitting machine in which the divided core is divided at the center of the teeth. Therefore, the rotating electric machine of Embodiment 5 can reduce material costs, improve manufacturability, reduce shaft voltage, and suppress torque ripple. Furthermore, distortion is less likely to occur in the winding slot 15, making it easier to insert the coil 16 and improving manufacturability.

[0085] Embodiment 6. Embodiment 6 is a configuration in which one side of the contact portion of the divided core is divided into a core back section and the other side into a teeth section.

[0086] The differences between the rotating electric machine of Embodiment 6 and Embodiment 1 will be explained based on Figure 27, a cross-sectional view of the divided core; Figure 28, a cross-sectional view of the 4-part, 6-pole, 54-slot double V-shaped embedded magnet type motor divided by core back division and tooth division; and Figure 29, a perspective view of the 45-degree rotating, two-stage shifted stator core. In Figures 27 to 29 of Embodiment 6, parts that are the same as or corresponding to those in Embodiment 1 are denoted by the same reference numerals. In order to distinguish them from the rotating electric machine 100 and divided core 12 of Embodiment 1, these are referred to as the rotating electric machine 600 and the divided core 612.

[0087] As shown in Figure 27, the segmented core 612 constituting the stator core 11 of the rotating electric machine 600 in Embodiment 6 is constructed by laminating multiple electromagnetic steel sheets and consists of multiple teeth 14 that protrude inward from the central axis from the arc-shaped core back 13, and winding slots 15 which are the areas between adjacent teeth 14. The segmented core 612 is divided by a core back segment on one contact area and a teeth segment on the other contact area. The teeth 14 are evenly distributed in the circumferential direction, with 13.5 teeth in total, and the arc angle of the segmented core 612 is 90 degrees.

[0088] As shown in Fig. 28, the rotating electrical machine 600 of Embodiment 6 has a stator core 11 constituted by the split core 612 described in Fig. 27, and the other configurations are the same as those of Embodiment 1.

[0089] As shown in Fig. 29, the stator core 11 is divided into two segments in the axial direction, and the segments of each stator core 11 are rotated by a mechanical angle of 45 degrees with respect to the axially adjacent segments and stacked in two stages in the axial direction. In this way, a 6-pole 54-slot embedded magnet type distributed winding motor using a four-split core is configured.

[0090] By configuring in this way, the yield of the electromagnetic steel of the split core 612 is improved, so that the material cost can be reduced. Furthermore, by adopting the split core 612 with a small number of splits, the number of parts can be reduced and the manufacturability can be improved. And the axial voltage generated by the combination of the number of poles and the number of splits of the stator core 11 can be reduced. Also, the torque ripple generated by the number of poles and the number of splits of the stator core 11 can be suppressed.

[0091] Also, although not shown, in a 6-pole 54-slot embedded magnet type distributed winding motor, if the rotating electrical machine satisfies the relationship between the number of pole pairs and the number of splits of P < N < 2P (Condition A) or 2P < N < 4P (Condition B), the same effects as those of Embodiment 6 can be obtained. At this time, the same effect can be obtained even if it is only either core back splitting or tooth splitting.

[0092] Also, even when the combination of the number of pole pairs and the number of slots is different, if the relationship between the number of pole pairs and the number of splits satisfies P < N < 2P (Condition A) or 2P < N < 4P (Condition B), the same effects can be obtained. Also, even with different rotor structures, if the relationship between the number of pole pairs and the number of splits satisfies P < N < 2P (Condition A) or 2P < N < 4P (Condition B), the same effects can be obtained.

[0093] Also, as in Embodiment 2, by assembling the split cores 612 with concavo-convex portions arranged at the abutting portions, the positioning accuracy of the split core 12 can be improved, and the manufacturability can be enhanced. Then, by welding the outer peripheral portion of the abutting portion of the split core 612, the rigidity of the stator core 11 can be further increased. Furthermore, by performing welding in the groove of the outer peripheral portion of the split core 612, the concavo-convex portions on the outer periphery of the stator core 11 are eliminated, and when the stator core 11 is inserted into a housing or the like, the assembly of the stator 10 becomes easier. At this time, the presence of grooves in the outer peripheral portion of the abutting portion of the split core 612 causes factors of permeance harmonics and generates shaft voltage. And it is conceivable that the shaft voltage increases due to the occurrence of shape variations in the grooves. However, by applying a split number that satisfies the relationship between the number of pole pairs and the split number of P < N < 2P (Condition A) or 2P < N < 4P (Condition B), the shaft voltage can be more effectively reduced.

[0094] And by adopting a structure in which they are stacked with a convolution of 45 mechanical degrees, the rigidity of the stator core 11 combined with the split cores 612 can be increased, and the vibration resistance and strength can be improved. Also, since the circumferential position of the winding slot 15 is the same in each segment, the insertion of the coil 16 becomes easy, and the manufacturability is improved. And the influence of magnetic anisotropy in the direction perpendicular to the rolling direction of the teeth 14 of the stator core 11 can be reduced, and the losses, torque ripple, and shaft voltage of the embedded magnet type motor can be reduced.

[0095] Also, when the gaps 21 formed at the abutting portions between the adjacent split cores 612, which were described as the configuration of the stator core 11 in Embodiment 6, have different widths and sizes from each other, by setting the split number to a small split number that satisfies P < N < 2P (Condition A), the permeance harmonics generated by the variations in the gaps 21 can be reduced, and the shaft voltage can be more effectively reduced.

[0096] Furthermore, if the number of circumferential divisions of the stator core 11 is N, the number of axial divisions of the stator core 11 is t, n is an integer, and k is a number satisfying k = t / n, then if the segments of the stator core 11, which are divided into t axial sections, are rotated by a mechanical angle of 360 / N / k degrees around the rotation axis of the rotor 30 relative to adjacent segments in the axial direction, and stacked t layers in the axial direction, the same effect as in Embodiment 3 can be achieved.

[0097] Furthermore, if t is a number satisfying t=4n, and the segments of the stator core 11, which are axially divided into t segments, are rotated by a mechanical angle of 360 / N / 4 degrees around the rotation axis of the rotor 30 relative to the adjacent segments in the axial direction, and stacked in t layers in the axial direction, the same effect as in Embodiment 4 can be achieved.

[0098] As described above, the rotating electric machine of Embodiment 6 has one side of the contact portion of the divided core divided into core back division and the other side divided into teeth division. Therefore, the rotating electric machine of Embodiment 6 can reduce material costs, improve manufacturability, reduce shaft voltage, and suppress torque ripple.

[0099] Although this application describes various exemplary embodiments and examples, the various features, aspects, and functions described in one or more embodiments are not limited to the application of a particular embodiment, but can be applied individually or in various combinations to the embodiments. Accordingly, countless variations not illustrated are conceivable within the scope of the art disclosed herein. These include, for example, modifying, adding or omitting at least one component, or even extracting at least one component and combining it with components of other embodiments. [Industrial applicability]

[0100] The rotating electric machine of this invention can be widely applied to rotating electric machines because it reduces material costs, improves manufacturability, reduces shaft voltage, and suppresses torque ripple. [Explanation of Symbols]

[0101] 10 Stator, 11 Stator core, 12, 212, 512, 612 Split core, 13 Core back, 14 Teeth, 15 Winding slot, 16 Coil, 21 Gap, 22 Groove, 23 Protrusion, 24 Recess, 30 Rotor, 31 Rotor core, 32 Shaft, 33 Permanent magnet, 34 Magnet slot, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 200, 300, 400, 500, 501, 600 Rotating electric machine.

Claims

1. A stator having a stator core formed by combining a plurality of circumferentially divided divided cores in an annular shape, and a coil wound in a distributed winding on the stator core, In a rotating electric machine having a rotor core fixed to a shaft at the central axis of the stator, magnetic poles with a pole pair number of P arranged on the rotor core, and a rotor rotatable relative to the stator, The divided core has an arc-shaped core back and a plurality of teeth protruding inward from the core back, with winding slots between the teeth, and the number of teeth is equal. If the number of divisions of the divided core is N, A rotating electric machine that satisfies P < N < 2P and N ≥ 6.

2. The rotating electric machine according to claim 1, wherein the stator core is joined to one another by welding at the outer circumference of the contact portions of the plurality of divided cores that make up the machine.

3. The rotating electric machine according to claim 2, wherein the stator core has grooves on the outer circumference of the contact portions of the plurality of segmented cores that make up the stator core.

4. The rotating electric machine according to claim 3, wherein the groove is used as a welding groove.

5. The divided core has a convex portion on one circumferential contact portion and a concave portion on the other circumferential contact portion. The rotating electric machine according to claim 4, wherein the stator core has a structure in which the recesses and protrusions of the contact portions of the divided core are fitted together.

6. If the number of winding slots in the stator core is an integer S, The rotating electric machine according to claim 5, wherein the number of circumferential divisions N of the stator core is a divisor of S.

7. The rotating electric machine according to claim 6, wherein the stator core is composed of divided cores that are divided from the circumferential center of the winding slot to the core back.

8. The rotating electric machine according to claim 6, wherein the stator core is composed of divided cores that are divided from the circumferential center of the teeth to the core back.

9. The rotating electric machine according to claim 6, wherein the stator core is composed of a divided core, one of which is divided from the circumferential center of the winding slot to the core back, and the other of which is divided from the circumferential center of the teeth to the core back.

10. Let S be the number of winding slots in the stator core, and under the conditions that t is an integer of 2 or more and n is an integer, The stator core is constructed by stacking t segments in the direction of the rotation axis, Each of the above segments is composed of a plurality of the above divided cores divided in the circumferential direction, The rotating electric machine according to any one of claims 1 to 9, wherein the segments adjacent in the direction of rotation are stacked in the axial direction by rotating them by a mechanical angle (360 / S) × n degrees around the rotation axis of the rotor.

11. Given that t is an integer greater than or equal to 2, n is an integer, and k satisfies the condition k = t / n, The stator core is constructed by stacking t segments in the direction of the rotation axis, Each of the above segments is composed of a plurality of the above divided cores divided in the circumferential direction, The rotating electric machine according to any one of claims 1 to 9, wherein the segments adjacent in the direction of rotation are stacked in the axial direction after being rotated by a mechanical angle of 360 / N / k degrees around the rotation axis of the rotor.

12. In the condition that n is an integer and t = 4n, The stator core is constructed by stacking t segments in the direction of the rotation axis, Each of the above segments is composed of a plurality of the above divided cores divided in the circumferential direction, The rotating electric machine according to any one of claims 1 to 9, wherein the segments adjacent in the direction of rotation are stacked in the axial direction by rotating them by a mechanical angle of 360 / N / 4 degrees around the rotation axis of the rotor.

13. The rotating electric machine according to any one of claims 1 to 9, wherein the rotor core is of the embedded magnet type, having a plurality of magnet slots for inserting and fixing magnets and a plurality of permanent magnets for forming magnetic poles.

Images