Rotary 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

rotating electrical machines

[0001] The present application relates to a rotating electric machine.

[0002] To reduce motor material costs, stator cores constructed by combining circumferentially divided core segments are widely used, as this can improve the yield of electromagnetic steel sheets. Dividing the stator core into smaller segments circumferentially also improves the yield of electromagnetic steel sheets, so from the perspective of reducing material costs, it is better to increase the number of segments in the stator core. However, using a large number of divided core segments increases the number of parts, which increases manufacturing costs and makes assembly more difficult. For this reason, motors using divided cores with a smaller number of segments are being considered.

[0003] A motor has been disclosed in which the remaining area inside the rotor is utilized to punch the divided cores together, thereby reducing material costs (for example, Patent Document 1).

[0004] Japanese Patent Application Laid-Open No. 2002-186227

[0005] On the other hand, when the magnetomotive force and permeance contain the same harmonic components, axial voltage is generated on the rotor shaft. In actual motors, combining split cores makes it difficult to prevent tiny air gaps between the split cores, which can cause permeance harmonics and axial voltage. In motors with mechanical bearings supporting the rotor, axial voltage can cause discharge between the shaft and bearing, leading to electrolytic corrosion of the bearing and resulting in vibration and noise. Therefore, a design that minimizes axial voltage is essential. Therefore, in motors with split cores, it is important to carefully consider the combination of the number of rotor poles and the number of stator segments. Even if air gaps occur between the split cores, axial voltage does not occur when the number of segments is an integer multiple of the number of poles. However, this can increase torque ripple.

[0006] Patent Document 1 does not mention shaft voltage and torque ripple, and the disclosed example has issues of shaft voltage occurring due to gaps between the divided cores, and increased torque ripple even though no shaft voltage is generated.

[0007] The present application discloses a technique for solving the above-described problems, and aims to provide a rotating electric machine that can reduce material costs, improve manufacturability, reduce shaft voltage, and suppress torque ripple.

[0008] The rotating electric machine disclosed in the present application has a stator having a stator core formed by combining a plurality of split cores divided circumferentially in an annular shape, and a coil wound in distributed winding on the stator core, and a rotor core fixed to a shaft located on the central axis of the stator, in which magnetic poles with a number of pole pairs P are arranged on the rotor core, and which is equipped with a rotor that can rotate relative to the stator, the split core has an arc-shaped core back and a plurality of teeth protruding inward from the core back, with winding slots between the teeth, the number of teeth is equal, and where N is the number of divisions of the split core, P < N < 2P is satisfied. The rotating electric machine disclosed in the present application has a stator having a stator core formed by combining a plurality of split cores divided circumferentially in an annular shape, and a coil wound in distributed winding on the stator core, and a rotor core fixed to a shaft located on the central axis of the stator, in which magnetic poles with a number of pole pairs P are arranged on the rotor core, and which is equipped with a rotor that can rotate relative to the stator, the split core has an arc-shaped core back and a plurality of teeth protruding inward from the core back, with winding slots between the teeth, the number of teeth is equal, and where N is the number of divisions of the split core, the relationship 2P < N < 4P is satisfied.

[0009] According to the rotating electric machine disclosed in the present application, it is possible to obtain a rotating electric machine that can reduce material costs, improve manufacturability, reduce shaft voltage, and suppress torque ripple.

[0010] 1 is a cross-sectional view of a 6-division, 8-pole, 48-slot double-V interior permanent magnet motor of a rotating electric machine according to a first embodiment; FIG. 2 is a cross-sectional view of a divided core constituting a stator core of the rotating electric machine according to the first embodiment; FIG. 3 is a perspective view of a stator core of the rotating electric machine according to the first embodiment; FIG. 4 is analytical data of maximum axial voltage using the number of divisions of the stator core of the rotating electric machine according to the first embodiment as a parameter; FIG. 5 is analytical data of torque ripple amplitude using the number of divisions of the stator core of the rotating electric machine according to the first embodiment as a parameter; FIG. 6 is a cross-sectional view of a 12-division, 8-pole, 48-slot double-V interior permanent magnet motor that is a modified example of the rotating electric machine according to the first embodiment; FIG. 7 is a cross-sectional view of a 6-division, 8-pole, 72-slot double-V interior permanent magnet motor that is a modified example of the rotating electric machine according to the first embodiment; FIG. 8 is a cross-sectional view of a 12-division, 8-pole, 96-slot double-V interior permanent magnet motor that is a modified example of the rotating electric machine according to the first embodiment; FIG. 9 is a cross-sectional view of an 8-division, 12-pole, 72-slot double-V interior permanent magnet motor that is a modified example of the rotating electric machine according to the first embodiment; FIG. 10 is a cross-sectional view of a 24-division, 16-pole, 96-slot double-V interior permanent magnet motor that is a modified example of the rotating electric machine according to the first embodiment; FIG. 1 is a cross-sectional view of a 6-division, 8-pole, 48-slot flat permanent magnet motor that is a modified example of the rotating electric machine according to embodiment 1. FIG. 2 is a cross-sectional view of a 12-division, 8-pole, 48-slot single-V-shaped permanent magnet motor that is a modified example of the rotating electric machine according to embodiment 1. FIG. 3 is a cross-sectional view of a 6-division, 8-pole, 48-slot triple-V-shaped permanent magnet motor that is a modified example of the rotating electric machine according to embodiment 1. FIG. 4 is a cross-sectional view of a 12-division, 8-pole, 48-slot V-shaped permanent magnet motor that is a modified example of the rotating electric machine according to embodiment 1. FIG. 5 is a cross-sectional view of a split core that constitutes a stator core of a rotating electric machine according to embodiment 2. FIG. 6 is a cross-sectional view of a 6-division, 8-pole, 48-slot double-V-shaped permanent magnet motor of a rotating electric machine according to embodiment 2. FIG. 7 is a perspective view of a 30-degree rotated, 4-stage rotated stator core of a rotating electric machine according to embodiment 3. FIG. 8 is an explanatory diagram of the rolling direction and the tooth direction in a cross-sectional view of a split core of a rotating electric machine according to embodiment 4. FIG. 9 is an explanatory diagram of tooth numbers in a cross-sectional view of a split core of a rotating electric machine according to embodiment 4. 10 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 a comparative example of the rotary electric machine according to Embodiment 4. FIG.10 is an explanatory diagram of the tooth direction component of the rolling direction magnetic characteristics of teeth at the same circumferential position in each segment of the stator core of the rotary electric machine according to embodiment 4. FIG. 11 is a cross-sectional view of a divided core constituting the stator core of the rotary electric machine according to embodiment 5. FIG. 12 is a cross-sectional view of a 6-split, 8-pole, 48-slot, double-V-shaped interior permanent magnet motor in which the stator core of the rotary electric machine according to embodiment 5 is divided at the center of the teeth. FIG. 13 is a perspective view of a 30-degree rotation, 6-stage rotated stator core of the rotary electric machine according to embodiment 5. FIG. 14 is a cross-sectional view of a 12-split, 8-pole, 48-slot, double-V-shaped interior permanent magnet motor in which the stator core of the rotary electric machine according to embodiment 5 is divided at the center of the teeth, which is a modified example of the rotary electric machine according to embodiment 5. FIG. 15 is a cross-sectional view of a divided core constituting the stator core of the rotary electric machine according to embodiment 6. FIG. 16 is a cross-sectional view of a 4-split, 6-pole, 54-slot, double-V-shaped interior permanent magnet motor in which the stator core of the rotary electric machine according to embodiment 6 is divided by core back division and tooth division. FIG. 17 is a perspective view of a 45-degree rotation, 2-stage rotated stator core of the rotary electric machine according to embodiment 6.

[0011] Embodiment 1. In embodiment 1, a rotating electric machine includes a stator having a stator core formed by combining a plurality of split cores divided in the circumferential direction into an annular shape, and a coil wound in distributed winding around the stator core, and a rotor core fixed to a shaft located on the central axis of the stator, in which magnetic poles with a number of pole pairs P are arranged on the rotor core, and which is equipped with a rotor that can rotate relative to the stator, the split core has an arc-shaped core back and a plurality of teeth protruding inward from the core back, with winding slots between the teeth, the number of teeth is equal, and where N is the number of divisions of the split core, P<N<2P or 2P<N<4P is satisfied.

[0012] The rotating electric machine according to the first embodiment will be described below with reference to Fig. 1, which is a cross-sectional view of a 6-division, 8-pole, 48-slot, double-V-shaped interior permanent magnet distributed winding motor, Fig. 2, which is a cross-sectional view of the divided cores that make up the stator core, Fig. 3, which is a perspective view of the stator core, Fig. 4, which shows analytical data of maximum shaft voltage using the number of divisions of the stator core as a parameter, Fig. 5, which shows analytical data of torque ripple amplitude using the number of divisions of the stator core as a parameter, and Figs. 6 to 14, which are cross-sectional views of interior permanent magnet distributed winding motors that are modified versions of the rotating electric machine. In each figure, the same or corresponding parts are designated by the same reference numerals, and duplicate explanations will be omitted.

[0013] In the following description, the direction of the rotational axis is defined as the axial direction (Z), the direction toward the center of the rotational axis (the direction from the outer periphery of the stator toward the center of the rotational axis) is defined as the radial direction (R), and the direction along the direction of rotation around the rotational axis is defined as the circumferential direction (P), and these definitions are also shown in the drawings as appropriate. Furthermore, since this application assumes that the rotating electric machine is an interior permanent magnet distributed winding motor, in the description, the interior permanent magnet distributed winding motor will be referred to as an interior permanent magnet motor as appropriate.

[0014] First, the overall structure of a rotating electric machine 100 according to a first embodiment will be described with reference to Fig. 1, which is a cross-sectional view taken along a plane perpendicular to the axial direction of the rotating electric machine 100, Fig. 2, which is a cross-sectional view of split cores constituting a stator core, and Fig. 3, which is a perspective view of the stator core. The rotating electric machine 100 is composed of a stator 10 and a rotor 30 that is coaxially arranged on the inner periphery of the stator 10 and is rotatable relative to the stator 10. The stator 10 includes a stator core 11, teeth 14, and coils 16. The stator core 11 is composed of split cores 12 divided into N segments (N is 6 in Fig. 1), as will be described later, and includes a core back 13, teeth 14, and winding slots 15. The rotor 30 includes a rotor core 31, a shaft 32, and permanent magnets 33.

[0015] First, the split core 12 that forms the basis of the stator 10 will be described with reference to Fig. 2. The split core 12 that constitutes the stator core 11 of the rotating electric machine 100 in the first embodiment is formed by laminating a plurality of electromagnetic steel sheets, and is composed of a plurality of teeth 14 that protrude inward from an arc-shaped core back 13 toward the central axis, and winding slots 15 that are the regions between adjacent teeth 14. The split core 12 is divided from the circumferential center of the winding slot 15 to the core back 13 (core back division). Eight teeth 14 are arranged circumferentially, and the arc angle of the split core 12 is 60 degrees.

[0016] Returning to FIG. 1 , the rotating electric machine 100 will be described. The stator core 11 is configured by arranging six of the split cores 12 described in FIG. 2 in an annular arrangement, with each split core 12 having the same number of teeth 14, for a total of 48 teeth 14 evenly spaced in the circumferential direction. Furthermore, in the stator core 11 of the first embodiment, minute gaps 21 are formed between the split cores 12 at the contact portions formed between adjacent split cores 12. In the stator core 11 of the first embodiment, these gaps 21 are formed at most locations of the contact portions between the split cores 12, within the range of manufacturing variations. Furthermore, the width and size of the gaps 21 are formed differently at the contact portions between the split cores 12.

[0017] Each winding slot 15 houses a coil 16, and each coil 16 is connected in series with the coils 16 housed in the six adjacent winding slots 15 in the circumferential direction.

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

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

[0020] Next, the shaft voltage and torque ripple generated in a rotating electric machine and a method for suppressing them will be described using the electromagnetic field analysis results shown in Figures 4 and 5. Figure 4 shows the analysis results of the maximum shaft voltage in an 8-pole, 48-slot distributed winding motor when the stator core 11 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, and 48 divisions) and a 25 μm air gap 21 is generated between each of the divided cores 12. Note that the maximum shaft voltage is normalized by the maximum shaft voltage value when the core is divided into 6 divisions. Figure 5 shows the analysis results of the torque ripple amplitude in an 8-pole, 48-slot distributed winding motor when the stator core 11 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, and 48 divisions) and a 25 μm air gap 21 is generated between each of the divided cores 12. However, the torque ripple amplitude is normalized by the torque ripple amplitude when divided into six parts.

[0021] It is known that shaft voltage, one of the issues addressed in this application, occurs when the same components are present in magnetomotive force harmonics and permeance harmonics. In motors that use circumferentially divided core segments 12 for the stator core 11, minute air gaps 21 occur between adjacent core segments, which cause permeance harmonics. In an 8-pole, 48-slot interior permanent magnet motor, when air gaps 21 occur between the divided core segments 12, shaft voltage occurs when the core segments are divided into 2, 3, 4, 6, or 12 segments. Furthermore, when the core segments are divided into 2 or 4, permeance harmonics with the same components as all of the magnetomotive force harmonics are included, so the shaft voltage is expected to be large.

[0022] As shown in FIG. 4, it was confirmed that an axial voltage is generated when the division is 2, 3, 4, 6, or 12, and that the axial voltage is large especially when the division is 2 or 4, because permeance harmonics of the same components as all of the magnetomotive force harmonics are present.

[0023] Furthermore, when the stator core 11 is divided into an integer multiple of the number of poles, no axial voltage is generated. However, if split cores 12 are used in a number that is an integer multiple of the number of poles and gaps 21 are generated between the split cores 12, there is a concern that torque ripple may increase.

[0024] 5, it can be seen that the torque ripple is approximately 5% greater in an 8-division interior permanent magnet motor than in a 6-division interior permanent magnet motor, which is the rotating electric machine 100 of embodiment 1. Furthermore, the torque ripple is also greater in interior permanent magnet motors with 16, 24, and 48 divisions, which are integer multiples of the number of poles, than in a 6-division interior permanent magnet motor.

[0025] From the above results, for an 8-pole, 48-slot interior permanent magnet motor, the division numbers deemed suitable from the perspective of both low shaft voltage and low torque ripple are 3, 6, and 12. The motors that can fully demonstrate the effect of reducing the material cost of the split core 12 are the 6-division motor of embodiment 1, which has a division number greater than the number of pole pairs P, and the 12-division motor shown in Figure 6, which will be described later. These division numbers satisfy the relationship P<N<2P (condition A) or 2P<N<4P (condition B).

[0026] As described above, in the first embodiment, by configuring the split core 12 of the rotating electric machine 100, the yield of the electromagnetic steel sheets of the split core 12 is improved, thereby reducing material costs. Furthermore, by using split core 12 with a small number of divisions, the number of parts is reduced, improving manufacturability. Furthermore, 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), the axial voltage generated by the combination of the number of poles and the number of divisions of the stator core 11 is reduced, and 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. Furthermore, the core-back split structure suppresses distortion of the teeth 14, reducing manufacturing distortion of the entire interior permanent magnet motor and reducing motor loss.

[0027] Here, the relationship between the number of divisions N of the split cores 12 and the number S of the winding slots 15 will be described. By setting the number of divisions N of the stator core 11 in the circumferential direction to be a divisor of S, the split cores 12 constituting the stator core 11 can all have the same shape, thereby reducing the manufacturing cost of the split cores 12.

[0028] Next, the relationships P<N<2P (condition A) and 2P<N<4P (condition B) will be described for modified examples of the 6-part, 8-pole, 48-slot, double-V-shaped interior permanent magnet distributed winding motor described in embodiment 1. Note that in each figure, the reference numerals are set to 101 and the like to distinguish them from the rotating electric machine 100 (6-part, 8-pole, 48-slot, double-V-shaped interior permanent magnet distributed winding motor) in FIG.

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

[0030] FIG. 11 is a cross-sectional view of an 8-pole, 48-slot, flat-plate, interior-magnet, distributed-winding motor (rotating electric machine 106) in which the stator core 11 is divided into six equal parts circumferentially by the core back 13. In this example, P<N<2P (Condition A) is satisfied. FIG. 12 is a cross-sectional view of an 8-pole, 48-slot, single-layer, V-shaped interior-magnet, distributed-winding motor (rotating electric machine 107) in which the stator core 11 is divided into 12 equal parts circumferentially by the core back 13. In this example, 2P<N<4P (Condition B) is satisfied. FIG. 13 is a cross-sectional view of an 8-pole, 48-slot, triple-layer, V-shaped interior-magnet, distributed-winding motor (rotating electric machine 108) in which the stator core 11 is divided into six equal parts circumferentially by the core back 13. In this example, P<N<2P (Condition A) is satisfied. FIG. 14 is a cross-sectional view of an 8-pole, 48-slot, V-shaped interior-magnet, distributed-winding motor (rotating electric machine 109) in which the stator core 11 is divided into 12 equal parts circumferentially by the core back 13. In this example, 2P<N<4P (condition B) is satisfied.

[0031] Here, the interior permanent magnet distributed winding motors of the modified examples shown in FIGS. 6 to 14 are summarized. The motor shown in FIG. 6 is an 8-pole, 48-slot distributed winding motor using a 12-segment core, which satisfies 2P<N<4P (condition B) and provides the same effects as the rotating electric machine of embodiment 1. As shown in FIGS. 7 to 10, even if the combination of the number of pole pairs and the number of slots is different, the same effects can be provided 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). As shown in FIGS. 11 to 14, even if the interior permanent magnet rotor structure is different, the same effects can be provided as the rotating electric machine of embodiment 1 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). Furthermore, although not shown, even in the surface-mounted type and wound field structure, if 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), the same effect as that of the rotating electric machine of embodiment 1 can be obtained.

[0032] Furthermore, when the gaps 21 formed at the contact portions between adjacent split cores 12, which have been described as the configuration of stator core 11 in embodiment 1, are formed to have different widths and sizes, by selecting a small number of divisions that satisfies P<N<2P (condition A), it is possible to reduce permeance harmonics generated by variations in gaps 21 and more effectively reduce the axial voltage.

[0033] As described above, the rotating electric machine of the first embodiment includes a stator having a stator core formed by combining a plurality of split cores divided in the circumferential direction into an annular shape and a coil wound in distributed winding around the stator core, and a rotor core fixed to a shaft located on the central axis of the stator, with magnetic poles having a number of pole pairs P arranged on the rotor core and a rotor that can rotate relative to the stator, the split core having an arc-shaped core back and a plurality of teeth protruding inward from the core back with winding slots between the teeth, the number of teeth being equal, and where N is the number of divisions of the split core, P<N<2P or 2P<N<4P is satisfied. Therefore, the first embodiment provides a rotating electric machine that reduces material costs, improves manufacturability, reduces shaft voltage, and suppresses torque ripple.

[0034] Second Embodiment In the second embodiment, projections and recesses for fitting are provided on the contact portions of the split cores, and grooves are provided on the outer periphery.

[0035] The rotating electric machine of the second embodiment will be described, focusing on the differences from the first embodiment, based on Fig. 15, which is a cross-sectional view of a split core that constitutes a stator core, and Fig. 16, which is a cross-sectional view of a 6-split, 8-pole, 48-slot, double-V-shaped interior permanent magnet motor. In Figs. 15 and 16 of the second embodiment, parts that are the same as or equivalent to those of the first embodiment are given the same reference numerals. Note that to distinguish the rotating electric machine 200 and split core 212 from the rotating electric machine 100 and split core 12 of the first embodiment, they are referred to as a rotating electric machine 200 and split core 212.

[0036] 15 , split cores 212 constituting stator core 11 of rotating electric machine 200 in embodiment 2 are formed by laminating multiple electromagnetic steel sheets and include multiple teeth 14 protruding inward from arc-shaped core back 13 toward the central axis, and winding slots 15 that are regions between adjacent teeth 14. Split core 212 is divided from the circumferential center of winding slot 15 to core back 13 (core back division). A convex portion 23 is provided on one side of the abutment portion of split core 212, and a concave portion 24 is provided on the other side, and grooves 22 are provided on the outer periphery. Eight teeth 14 are arranged circumferentially, and the arc angle of split core 212 is 60 degrees.

[0037] 16, an interior permanent magnet motor, which is a rotating electric machine 200 according to the second embodiment, is configured with a stator 10 and a rotor 30 that is coaxially arranged on the inner periphery of the stator 10 and is rotatable relative to the stator 10. The stator 10 includes a stator core 11, teeth 14, and coils 16. The stator core 11 is configured by arranging six split cores 212, as described in FIG. 15, in an annular shape, resulting in 48 teeth 14 evenly spaced in the circumferential direction. Each coil 16 is connected in series with the coil 16 housed in the winding slot 15 that is six circumferentially adjacent to the other coils. The remaining configuration is the same as that of the first embodiment.

[0038] The split cores 212 are assembled so that the convex portions 23 and concave portions 24 of each split core 212 fit with the adjacent split cores 212, and are fixed by welding in the grooves 22 on the outer periphery of the abutting portions. In addition, in the stator core 11 of the second embodiment, the outer peripheries of the abutting portions formed between the split cores 212 arranged adjacent to each other are joined by welding without any gaps.

[0039] Meanwhile, minute gaps 21 are formed on the inner circumferential side of the abutment portions between the split cores 212. In the stator core 11 of the second embodiment, these gaps 21 are formed at almost all locations of the abutment portions between the split cores 212 within the range of manufacturing variation, and the width and size of the gaps 21 differ from one another at the abutment portions between the split cores 212. Particularly in a structure in which the outer peripheries are joined by welding, the radial penetration depth of the welded joined region varies relatively greatly during manufacturing. Therefore, as described above, the radial width of the minute gaps 21 remaining on the inner circumferential side varies relatively greatly.

[0040] In this way, the use of split cores 212 improves the yield of electromagnetic steel sheets, thereby reducing material costs. Furthermore, the use of split cores 212 with a small number of divisions reduces the number of parts, improving manufacturability. Furthermore, 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), the axial voltage generated by the combination of the number of poles and the number of divisions of the stator core 11 can be reduced. Furthermore, torque ripple generated by the number of poles and the number of divisions of the stator core 11 can also be suppressed.

[0041] Assembling the split cores 212 using the protrusions 23 and recesses 24 at their contact points improves the positioning accuracy of the split cores 212 and manufacturability. Furthermore, welding the outer periphery of the contact points between the split cores 212 increases the rigidity of the stator core 11. Joining the split cores 212 using the grooves 22 as welding grooves prevents the weld bead from protruding from the outer periphery of the stator core 11, eliminating unevenness on the outer periphery of the stator core 11. This facilitates assembly of the stator 10 when press-fitting it into a housing. Furthermore, the structure in which the winding slots 15 are divided from the circumferential center to the core back 13 (core back division) suppresses distortion of the teeth 14, reduces manufacturing distortion of the entire interior permanent magnet motor, and reduces motor loss.

[0042] Furthermore, the number N of circumferential divisions of the stator core 11 is a divisor of the number S of winding slots 15, and the shapes of the divided cores 12 that make up the stator core 11 can all be made the same, thereby reducing the manufacturing costs of the divided cores 212.

[0043] On the other hand, as in the second embodiment, the presence of grooves 22 on the outer periphery of the abutting portion of the split core 212 causes permeance harmonics, generating axial voltage. It is conceivable that variations in the shape of the grooves 22 increase the axial voltage. However, by adopting a division number that satisfies P<N<2P (condition A) or 2P<N<4P (condition B) as described in the first embodiment, the axial voltage can be reduced more effectively.

[0044] Furthermore, although not shown, even when the combination of the number of pole pairs and the number of slots is different, the same effect can be achieved 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).

[0045] Although not shown, even if the rotor structure is different, the same effect can be achieved as long as the above-mentioned 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.

[0046] Furthermore, when the gaps 21 formed at the contact portions between adjacent split cores 212 described as the configuration of stator core 11 in embodiment 2 are formed to have different widths and sizes, by using a small number of divisions that satisfies P<N<2P (condition A), it is possible to reduce permeance harmonics generated by variations in gaps 21 and more effectively reduce the axial voltage.

[0047] In the second embodiment, a preferred example of a fixing structure between adjacent split cores 212 has been described, in which the split cores 212 are fixed by reinforcing the split cores with welding. However, the fixing structure between adjacent split cores 212 can also be a structure in which the stator core 11 is joined in an annular shape only by the fitting structure of the convex portions 23 and concave portions 24 of the split cores 212, and an annular frame is fitted around the outer periphery of the stator core 11. In this case, joining by welding can be omitted. Alternatively, an adhesive such as resin can be placed between adjacent split cores 212 to bond and fix them to each other.

[0048] Even in the case of these fixed structures, particularly when a gap 21 is formed at the contact point between adjacent split cores 212, and even when the widths and sizes of each split core are different from each other, the effect described in embodiment 1 can be obtained as long as the 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.

[0049] As described above, the rotating electric machine of the second embodiment has projections and recesses for fitting into the abutment portions of the split cores and grooves on the outer periphery, and 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). Therefore, the rotating electric machine of the second embodiment can reduce material costs, improve manufacturability, reduce shaft voltage, and suppress torque ripple.

[0050] Third Embodiment In the third embodiment, the stator core is divided into four parts in the axial direction, and the four parts are rotated by 30 degrees and then stacked.

[0051] The rotating electric machine of the third embodiment will be described, focusing on the differences from the first embodiment, based on Fig. 17, which is a perspective view of a 30-degree rotation four-stage rotated stator core. In Fig. 17 of the third embodiment, parts that are the same as or equivalent to those of the first embodiment are given the same reference numerals. Note that the rotating electric machine is referred to as a rotating electric machine 300 to distinguish it from the first embodiment.

[0052] The stator core 11 of the rotating electric machine 300 of the third embodiment 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. Segment B is rotated by a mechanical angle of 30 degrees relative to segment A, segment C is rotated by a mechanical angle of 30 degrees relative to segment B, and segment D is rotated by a mechanical angle of 30 degrees relative to segment C, with segments A to D stacked in the axial direction, with the rotation axis of the rotor 30 as the axis. Each segment of the stator core 11 is composed of six divided cores 12. The rest of the structure is the same as that of the rotating electric machine of the first embodiment.

[0053] This configuration not only achieves the effects of the rotating electric machine of embodiment 1, but also increases the rigidity of stator core 11, which is formed by combining split cores 12, improving vibration resistance and strength. Also, because the circumferential positions of winding slots 15 are the same in each segment, insertion of coils 16 is easier and manufacturability is improved. Furthermore, the effects of magnetic anisotropy in the direction perpendicular to the rolling direction of teeth 14 of stator core 11, which will be described later, are reduced, reducing loss, shaft voltage, and torque ripple in the interior permanent magnet motor.

[0054] Let N (an integer) be the number of divisions of stator core 11 in the circumferential direction, t (an integer of 2 or more) be the number of divisions of stator core 11 in the axial direction, n be an integer, and k be an integer satisfying k = t / n. If the t segments of stator core 11 divided into the axial direction are configured to be stacked in the axial direction while being rotated by a mechanical angle of 360 / N / k degrees around the rotation axis of rotor 30 relative to adjacent segments in the axial direction, the same effect as in the third embodiment can be achieved.

[0055] This is also generalized using the number S of winding slots 15 of stator core 11. If the segments of stator core 11, which are divided into t segments in the axial direction, are stacked in the axial direction while being rotated by a mechanical angle of (360 / S)×n degrees about the rotation axis of rotor 30 relative to adjacent segments in the axial direction, the same effect as in the third embodiment can be achieved.

[0056] Furthermore, as in the second embodiment, assembling the split cores 12 with concave and convex portions at their abutting portions increases the positioning accuracy of the split cores 12, improving manufacturability. Furthermore, welding the outer peripheries of the abutting portions of the split cores 12 increases the rigidity of the stator core 11. Furthermore, welding the grooves on the outer periphery of the split cores 12 eliminates the concave and convex portions on the outer periphery of the stator core 11, 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 the third embodiment is formed by dividing the stator core into four axial sections, rotating them 30 degrees, and stacking them. Therefore, the rotating electric machine of the third embodiment can reduce material costs, improve manufacturability, reduce axial voltage, and suppress torque ripple. Furthermore, the rigidity of the stator core 11 can be increased, improving vibration resistance and strength, and reducing the effects of magnetic anisotropy in the direction perpendicular to the rolling direction of the teeth 14 of the stator core 11.

[0058] Fourth Embodiment In a fourth embodiment, the magnetic anisotropy of the teeth of the stator core is balanced throughout the entire interior permanent magnet motor.

[0059] The rotating electric machine of embodiment 4 will be described, focusing on the differences from embodiment 1, with reference to Fig. 18, which is an explanatory diagram of the rolling direction and tooth direction in a cross-sectional view of a split core, Fig. 19, which is an explanatory diagram of tooth numbers in a cross-sectional view of a split core, Fig. 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 a stator core in a comparative example, Fig. 21, which is a perspective view of the stator core, and Fig. 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 Figs. 18, 19, and 21 of embodiment 4, parts that are the same as or equivalent to those of embodiment 1 are given the same reference numerals. Note that to distinguish it from rotating electric machine 100 of embodiment 1, it is referred to as rotating electric machine 400.

[0060] In Figure 18, the rolling direction is labeled "RD" and the teeth direction is labeled "TD." The angle between the rolling direction vector and the teeth direction vector is labeled θ. The magnetic properties of the electromagnetic steel sheets that make up the split core 12 may differ between the rolling direction and the direction perpendicular to the rolling direction. As shown in Figure 18, the teeth direction, which is the direction in which the teeth 14 face the center of rotation, does not match the rolling direction for all teeth 14. To make the following explanation easier to understand, teeth numbers are labeled in Figure 19. The teeth of the split core 12 are numbered counterclockwise around the periphery. Teeth numbers 1 to 8 are labeled TN1, TN2, TN3, TN4, TN5, TN6, TN7, and TN8.

[0061] When the angle between the rolling direction vector and the teeth direction vector is θ, the teeth direction component of the rolling direction magnetic property of each tooth 14 is calculated as the cosine of the rolling direction vector. When the segments of the stator core 11 arranged in four axial stages are combined, the sum of the teeth direction components of the rolling direction magnetic property of the teeth 14 at the same circumferential position is calculated.

[0062] First, as a comparative example, FIG. 20 illustrates a case where the stator core 11 described in FIG. 17 of the rotating electric machine 300 according to the third embodiment is divided into four sections, with each section rotated at 30 degrees. FIG. 20 shows the results of calculating the tooth direction components of the rolling direction magnetic properties of each of teeth No. 1 to No. 8 of the stator core 11 at the same circumferential position of each segment. The sum of the tooth direction components of the rolling direction magnetic properties of teeth 14 at the same circumferential position results in two values: 3.79 and 3.86. This shows that the stator core 11 described in FIG. 17 has different magnetic properties in the tooth direction components. Therefore, the magnetic anisotropy of the teeth 14 of the stator core 11 in the direction perpendicular to the rolling direction may increase losses in the interior permanent magnet motor, generate axial voltage, and increase torque ripple.

[0063] 21 , the stator core 11 of the rotating electric machine 400 of the fourth embodiment 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, and segments A to D are stacked in the axial direction. Furthermore, each segment of the stator core 11 is composed of six divided cores 12. The rest of the structure is the same as that of the first embodiment.

[0064] Fig. 22 shows the results of calculating the tooth direction components of the rolling direction magnetic properties of tooth numbers 1 to 8 of stator core 11 of rotating electric machine 400 of embodiment 4 shown in Fig. 21 at the same circumferential position of each segment. When the segments of four stages of stator core 11 are combined, the sum of all tooth direction components is 3.82, which shows 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 stator core 11 in the direction perpendicular to the rolling direction can be balanced throughout the entire interior permanent magnet motor. This reduces loss, axial voltage, and torque ripple in the interior permanent magnet motor. Furthermore, the rigidity of stator core 11, which combines split cores 12, can be increased, improving vibration resistance and strength. Furthermore, because the circumferential position of winding slots 15 is the same in each segment, insertion of coils 16 is simplified, improving manufacturability.

[0066] Here, the number of divisions of stator core 11 in the circumferential direction is N, the number of divisions of stator core 11 in the axial direction is t, n is an integer, and t is a number that satisfies t = 4n, and this is generalized. The same effect can be achieved by rotating each of t segments of stator core 11, which is divided into axial portions, by a mechanical angle of 360 / N / 4 degrees around the rotation axis of rotor 30 relative to the adjacent segment in the axial direction and stacking them in t layers in the axial direction.

[0067] As described in the second embodiment, assembling the split cores 12 by arranging concave and convex portions at their abutting portions increases the positioning accuracy of the split cores 12 and improves manufacturability. Furthermore, welding the outer peripheries of the abutting portions increases the rigidity of the stator core 11. Furthermore, welding the grooves on the outer periphery of the abutting portions of the split cores 12 eliminates the concave and convex portions on the outer periphery of the stator core 11, 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 the fourth embodiment balances the magnetic anisotropy of the teeth of the stator core throughout the entire interior permanent magnet motor. Therefore, the rotating electric machine of the fourth embodiment can reduce material costs, improve manufacturability, reduce axial voltage, and suppress torque ripple. Furthermore, the effects of magnetic anisotropy in the direction perpendicular to the rolling direction of the teeth 14 of the stator core 11 are balanced, increasing the rigidity of the stator core 11 and improving its vibration resistance and strength.

[0069] Fifth Embodiment In a fifth embodiment, the split core is split at the center of the teeth to form split teeth.

[0070] The rotating electric machine of embodiment 5 will be described, focusing on the differences from embodiment 1, based on Fig. 23, which is a cross-sectional view of a split core constituting a stator core; Fig. 24, which is a cross-sectional view of a 6-split, 8-pole, 48-slot, double-V-shaped interior permanent magnet motor in which the stator core is split at the center of the teeth; Fig. 25, which is a perspective view of a 30-degree rotated, 6-stage, rotated stator core; and Fig. 26, which is a cross-sectional view of a modified 12-split, 8-pole, 48-slot, double-V-shaped interior permanent magnet motor in which the stator core is split at the center of the teeth. In Figs. 23 to 26 of embodiment 5, parts that are the same as or equivalent to those of embodiment 1 are given the same reference numerals. Note that to distinguish the rotating electric machine 500 and split core 512 from the rotating electric machine 100 and split core 12 of embodiment 1, the rotating electric machine 500 and split core 512 are used.

[0071] 23 , split cores 512 constituting stator core 11 of rotating electric machine 500 in embodiment 5 are formed by laminating multiple electromagnetic steel sheets, and are configured with multiple teeth 14 protruding inward from arc-shaped core back 13 toward the central axis, and winding slots 15 that are regions between adjacent teeth 14. Split cores 512 are divided from the circumferential center of teeth 14 to core back 13 (teeth division). Each split core 512 has eight teeth 14 arranged circumferentially, and the arc angle of split core 512 is 60 degrees.

[0072] As shown in FIG. 24, in a rotating electrical machine 500 according to the fifth embodiment, the stator core 11 is formed by the split core 512 described with reference to FIG. 23, and the other configurations are the same as those of the first embodiment.

[0073] As shown in Fig. 25, the stator core 11 is divided into six segments (SGA, SGB, SGC, SGD, SGE, and 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 the axially adjacent segment. In the figure, segment E is denoted as SGE, and segment F is denoted as SGF.

[0074] With this configuration, the split core 512 improves the yield of the electromagnetic steel sheets, thereby reducing material costs. Furthermore, by using split core 512 with a small number of divisions, the number of parts can be reduced, improving manufacturability. Also, the axial voltage generated by the combination of the number of poles and the number of divisions of stator core 11 can be reduced. Furthermore, the torque ripple generated by the number of poles and the number of divisions of stator core 11 can be suppressed.

[0075] Furthermore, with the teeth division, the division position is outside the winding slot 15, so distortion is less likely to occur in the winding slot 15, making it easier to insert the coil 16 and improving manufacturability.

[0076] Furthermore, the number N of circumferential divisions of the stator core 11 is a divisor of the number S of winding slots 15, and the shapes of the divided cores 12 that make up the stator core 11 can all be made the same, thereby reducing the manufacturing costs of the divided cores 512.

[0077] 26 shows an 8-pole, 48-slot distributed winding motor using a 12-division core, but if the rotating electric machine satisfies P<N<2P (condition A) or 2P<N<4P (condition B), where P is the number of pole pairs and N is the number of equal divisions of stator core 11 in the circumferential direction, the same effects as in embodiment 5 can be achieved. Note that in FIG. 26, the rotating electric machine is referred to as rotating electric machine 501 to distinguish it from rotating electric machines 500 in FIGS. 24 and 25.

[0078] Even when the combination of the number of pole pairs and the number of slots is different, the same effect can be achieved 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). Furthermore, even when the rotor structure is different, the same effect can be achieved as long as the 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] Furthermore, as in the second embodiment, assembling the split cores 512 with concave and convex portions at their contact points improves the positioning accuracy of the split cores 12 and manufacturability. Furthermore, welding the outer peripheries of the split cores 512 at their contact points further increases the rigidity of the stator core 11. Furthermore, welding the grooves on the outer periphery of the split cores 512 eliminates the convex and concave portions on the outer periphery of the stator core 11, making it easier to assemble the stator 10 when inserting the stator core 11 into a housing or the like. In this case, the presence of grooves on the outer periphery of the split cores 512 at their contact points can cause permeance harmonics and generate axial voltage. Shape variations in the grooves can increase the axial voltage. However, by using a number of divisions such that 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), axial voltage can be more effectively reduced.

[0080] Furthermore, when the gaps 21 formed at the contact portions between adjacent split cores 512 described as the configuration of stator core 11 in embodiment 5 are formed to have different widths and sizes, by using a small number of divisions that satisfies P<N<2P (condition A), it is possible to reduce permeance harmonics generated by variations in gaps 21 and more effectively reduce the axial voltage.

[0081] By stacking the split cores 512 by rotating them by a mechanical angle of 30 degrees, the rigidity of the stator core 11 combined with the split cores 512 can be increased, improving vibration resistance and strength. Furthermore, since the circumferential position of the winding slots 15 is the same in each segment, the 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 are reduced, reducing loss, torque ripple, and axial voltage in the interior permanent magnet motor.

[0082] Furthermore, when 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 that satisfies k=t / n, if the segments of the stator core 11 that are divided into t axial divisions are rotated by a mechanical angle of 360 / N / k degrees relative to adjacent segments in the axial direction and stacked in t layers in the axial direction, the same effect as in embodiment 3 can be achieved.

[0083] Furthermore, when t is a number that satisfies t = 4n, if the segments of the stator core 11 divided into t pieces in the axial direction are rotated by a mechanical angle of 360 / N / 4 degrees relative to 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.

[0084] As described above, the rotating electric machine of the fifth embodiment has a split core that is split at the center of the teeth. Therefore, the rotating electric machine of the fifth embodiment can reduce material costs, improve manufacturability, reduce shaft voltage, and suppress torque ripple. Furthermore, distortion of the winding slots 15 is less likely to occur, making it easier to insert the coils 16 and improving manufacturability.

[0085] Sixth Embodiment In a sixth embodiment, one of the contact portions of the split core is divided into a core back and the other is divided into teeth.

[0086] The rotating electric machine of embodiment 6 will be described, focusing on the differences from embodiment 1, based on Fig. 27, which is a cross-sectional view of a split core, Fig. 28, which is a cross-sectional view of a four-split, 6-pole, 54-slot, double-V-shaped interior permanent magnet motor split by core back split and tooth split, and Fig. 29, which is a perspective view of a 45-degree rotated, two-stage rotated stator core. In Figs. 27 to 29 of embodiment 6, parts that are the same as or equivalent to those of embodiment 1 are given the same reference numerals. Note that to distinguish from rotating electric machine 100 and split core 12 of embodiment 1, they are referred to as rotating electric machine 600 and split core 612.

[0087] 27 , the split core 612 constituting the stator core 11 of the rotating electric machine 600 in the sixth embodiment is formed by laminating a plurality of electromagnetic steel sheets, and is composed of a plurality of teeth 14 protruding inward from the arc-shaped core back 13 toward the central axis, and winding slots 15 which are the regions between adjacent teeth 14. One abutting portion of the split core 612 is divided into a core back division, and the other abutting portion is divided into a tooth division. The teeth 14 are arranged evenly in the circumferential direction, totaling 13.5, and the arc angle of the split core 612 is 90 degrees.

[0088] As shown in FIG. 28, in a rotating electrical machine 600 according to the sixth embodiment, the stator core 11 is formed by the split core 612 described with reference to FIG. 27, and the other configurations are the same as those of the first embodiment.

[0089] 29, the stator core 11 is divided into two segments in the axial direction, and each segment of the stator core 11 is rotated by a mechanical angle of 45 degrees relative to the adjacent segment in the axial direction and stacked in two stages in the axial direction. In this way, a 6-pole, 54-slot interior permanent magnet distributed winding motor using a four-split core is constructed.

[0090] This configuration improves the yield of the electromagnetic steel of the split core 612, thereby reducing material costs. Furthermore, by using split core 612 with a small number of divisions, the number of parts can be reduced, improving manufacturability. This also reduces the axial voltage generated by the combination of the number of poles and the number of divisions of the stator core 11. It also reduces torque ripple generated by the combination of the number of poles and the number of divisions of the stator core 11.

[0091] Furthermore, although not shown, a 6-pole, 54-slot interior permanent magnet distributed winding motor also provides the same effect as in embodiment 6, provided that 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). In this case, the same effect can be obtained with only either core-back division or teeth division.

[0092] Even when the combination of the number of pole pairs and the number of slots is different, the same effect can be achieved 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 when the rotor structure is different, the same effect can be achieved 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).

[0093] Furthermore, as in the second embodiment, assembling the split cores 612 with concave and convex portions at their contact points improves the positioning accuracy of the split cores 12 and manufacturability. Furthermore, welding the outer peripheries of the split cores 612 at their contact points further increases the rigidity of the stator core 11. Furthermore, welding the grooves on the outer periphery of the split cores 612 eliminates the unevenness of the outer periphery of the stator core 11, making it easier to assemble the stator 10 when inserting the stator core 11 into a housing or the like. In this case, the presence of grooves on the outer periphery of the split cores 612 at their contact points can cause permeance harmonics and generate axial voltage. Shape variations in the grooves can increase the axial voltage. However, by using a number of divisions such that 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), axial voltage can be more effectively reduced.

[0094] By stacking the split cores 612 by rotating them by a mechanical angle of 45 degrees, the rigidity of the stator core 11 combined with the split cores 612 can be increased, improving vibration resistance and strength. Also, because the circumferential position of the winding slots 15 is the same in each segment, insertion of the coils 16 is simplified, improving manufacturability. This also reduces the effects of magnetic anisotropy in the direction perpendicular to the rolling direction of the teeth 14 of the stator core 11, reducing loss, torque ripple, and axial voltage in the interior permanent magnet motor.

[0095] Furthermore, when the gaps 21 formed at the contact portions between adjacent split cores 612 described as the configuration of stator core 11 in embodiment 6 are formed to have different widths and sizes, by using a small number of divisions that satisfies P<N<2P (condition A), it is possible to reduce permeance harmonics generated by variations in gaps 21 and more effectively reduce the axial voltage.

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

[0097] Furthermore, when t is a number that satisfies t = 4n, if the segments of the stator core 11 divided into t pieces in the axial direction are rotated by a mechanical angle of 360 / N / 4 degrees around the rotation axis of the rotor 30 relative to 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, in the rotating electric machine of the sixth embodiment, one of the contact portions of the split core is divided into a core back and the other is divided into teeth. Therefore, the rotating electric machine of the sixth embodiment can reduce material costs, improve manufacturability, reduce shaft voltage, and suppress torque ripple.

[0099] Although various exemplary embodiments and examples are described in this application, the various features, aspects, and functions described in one or more embodiments are not limited to the application of a particular embodiment, but may be applied to the embodiments alone or in various combinations. Therefore, countless modifications not illustrated are contemplated within the scope of the technology disclosed in this application. For example, this includes cases where at least one component is modified, added, or omitted, or where at least one component is extracted and combined with components of another embodiment.

[0100] The rotating electric machine of the present application can reduce material costs, improve manufacturability, reduce shaft voltage, and suppress torque ripple, and therefore can be widely applied to rotating electric machines.

[0101] 10 stator, 11 stator core, 12, 212, 512, 612 split core, 13 core back, 14 teeth, 15 winding slot, 16 coil, 21 air gap, 22 groove, 23 convex portion, 24 concave portion, 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 in which a plurality of split cores divided in a circumferential direction are combined in an annular shape, and a coil wound in a distributed winding manner on the stator core; A rotating electric machine having a rotor core fixed to a shaft on a central axis of the stator, magnetic poles having a number of pole pairs P arranged on the rotor core, and a rotor rotatable relative to the stator, The split 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 split core is N, then: A rotating electric motor that satisfies P<N<2P.

2. A stator having a stator core in which a plurality of split cores divided in a circumferential direction are combined in an annular shape, and a coil wound in a distributed winding manner on the stator core; A rotating electric machine having a rotor core fixed to a shaft on a central axis of the stator, magnetic poles having a number of pole pairs P arranged on the rotor core, and a rotor rotatable relative to the stator, The split 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 split core is N, then: A rotating motor that satisfies 2P<N<4P.

3. 2. The rotating electric machine according to claim 1, wherein a gap is provided at a contact portion formed between the adjacent split cores.

4. A rotating electric motor as described in claim 2, having a gap at the abutment portion formed between the split cores arranged adjacent to each other.

5. 4. The rotating electric machine according to claim 3, wherein the width or size of the gap varies for each of the contact portions of the split cores.

6. A rotating electric motor as described in claim 4, wherein the width or size of the gap varies for each abutment portion of the split core.

7. 7. The rotating electric machine according to claim 1, wherein the split cores of the stator core are joined to each other by welding at outer peripheries of contact portions of the split cores.

8. 7. The rotating electric machine according to claim 1, wherein the stator core has grooves on outer circumferential surfaces of the contact portions of the plurality of split cores.

9. 9. The rotating electric machine according to claim 8, wherein the groove is used as a welding groove.

10. a projection on one of the divided cores at a circumferential contact portion and a recess on the other of the divided cores at a circumferential contact portion, 7. The rotating electric machine according to claim 1, wherein the stator core is structured so that the recesses and the protrusions of the contact portions of the split cores are fitted into each other.

11. If the number of the winding slots of the stator core is an integer S, 7. The rotating electric machine according to claim 1, wherein a number N of divisions of the stator core in the circumferential direction is a divisor of S.

12. 7. The rotating electric machine according to claim 1, wherein the stator core is constituted by the split core that is split from a circumferential center of the winding slot to the core back.

13. 7. The rotating electric machine according to claim 1, wherein the stator core is constituted by the split cores that are split from circumferential central portions of the teeth to the core back.

14. 7. The rotating electric machine according to claim 1, wherein the stator core is composed of a split core, one of which is split from the circumferential center of the winding slot to the core back, and the other of which is split from the circumferential center of the teeth to the core back.

15. The number of winding slots of the stator core is an integer S, t is an integer equal to or greater than 2, and n is an integer, The stator core is configured by stacking t segments in a direction of a rotation axis, Each of the segments is constituted by a plurality of the split cores divided in a circumferential direction, 7. A rotating electric machine according to claim 1, wherein the segments adjacent in the direction of the rotation axis are stacked in the axial direction by rotating a mechanical angle of (360 / S) x n degrees around the rotation axis of the rotor.

16. where t is an integer of 2 or more, n is an integer, and k satisfies k=t / n. The stator core is configured by stacking t segments in a direction of a rotation axis, Each of the segments is constituted by a plurality of the split cores divided in a circumferential direction, 7. A rotating electric machine according to claim 1, wherein the segments adjacent in the direction of the rotation axis are stacked in the axial direction by rotating a mechanical angle of 360 / N / k degrees around the rotation axis of the rotor.

17. where t is an integer of 2 or more, n is an integer, and t=4n is satisfied. The stator core is configured by stacking t segments in a direction of a rotation axis, Each of the segments is constituted by a plurality of the split cores divided in a circumferential direction, 7. The rotating electric machine according to claim 1, wherein the segments adjacent in the direction of the rotation axis are stacked in the axial direction by rotating a mechanical angle of 360 / N / 4 degrees around the rotation axis of the rotor.

18. 7. The rotating electric machine according to claim 1, wherein the rotor core is an embedded magnet type having a plurality of magnet slots for inserting and fixing magnets and a plurality of permanent magnets for forming magnetic poles.