JP2011172359A - Split rotor and electric motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To strike a balance between the suppression of the occurrence of leakage magnetic flux from a permanent magnet and the easy and sure connection of outer circumferential side core pieces with rotor shaft side core pieces. <P>SOLUTION: A core of a rotor is split into the outer circumferential side core pieces 121a-121d relatively positioned on the outer circumference of the split rotor 120, and rotating shaft side core pieces 122 relatively positioned on the rotating shaft side of the split rotor 120, core piece coupling members 123a-123d are inserted into through-holes 125 formed on the outer circumferential side core pieces 121a-121d, and both ends of the core piece coupling members 123a-123d are fixed to end plates 150a, 150b. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a split-type rotor and an electric motor, and is particularly suitable for use as a rotor incorporating a permanent magnet.

Conventionally, in an electric vehicle or the like, an IPM (Interior Permanent Magnet) motor having high efficiency and high durability has been used. This IPM motor uses a rotor with a built-in permanent magnet.
The present inventor has proposed a technique described in Japanese Patent Application No. 2009-37045 as a technique for suppressing leakage magnetic flux from a permanent magnet in such an IPM motor. In this technique, a split-type rotor configured by combining a plurality of iron core pieces is employed as the rotor. The split type rotor includes a plurality of outer peripheral side core pieces relatively disposed on the outer peripheral side of the split type rotor, and a rotary shaft side core piece relatively positioned on the rotary shaft side of the split type rotor. And two permanent magnets are arranged at intervals in the outer circumferential direction of the split-type rotor, and the magnetic path between the outer peripheral side core piece and the rotary shaft side core piece is interrupted. A non-magnetic core piece coupling member is fitted to the outer peripheral side core piece and the rotating shaft side core piece.
By doing in this way, generation | occurrence | production of the leakage magnetic flux from a permanent magnet can be suppressed rather than before.

  However, in the above-described technique, the shape of the core piece coupling member must be determined so that it can be fitted to the outer peripheral side core piece and the rotating shaft side core piece. For this reason, when the shape of the iron core piece coupling member becomes complicated, the processing becomes difficult. Moreover, it is necessary to prevent backlash from occurring in the iron core piece coupling member when fitted to the outer peripheral side iron core piece and the rotating shaft side iron core piece. For this reason, it is necessary to manufacture an outer peripheral side iron core piece, a rotating shaft side iron core piece, and an iron core piece coupling member with high dimensional accuracy. Furthermore, since the core piece connecting member is fitted to the outer peripheral side core piece and the rotary shaft side core piece, the outer peripheral side core piece and the rotary shaft side core piece are fastened, so the core piece connecting member has high strength. Required. In particular, when the rotational speed of the motor increases, the centrifugal force acting on the outer peripheral core piece increases, and a special high-strength material must be used for the core piece coupling member in order to counter this centrifugal force.

  The present invention has been made in view of the above problems, and it is easy to suppress the generation of leakage magnetic flux from a permanent magnet, and to easily connect the outer peripheral side core piece and the rotary shaft side core piece. The purpose is to enable both of the reliable connection and the realization.

The split-type rotor according to the present invention includes an outer peripheral side iron core piece disposed relatively on the outer peripheral side, a rotary shaft side core piece relatively disposed on the rotary shaft side, the outer peripheral side iron core piece, and the rotary shaft. A plurality of permanent magnets arranged at intervals in the circumferential direction between the side iron core pieces, and two end plates arranged at both ends in the rotation axis direction, and the outer circumference side iron core pieces A split-type rotor in which a through-hole in the rotation axis direction is formed, and has an iron core piece coupling member inserted into the through-hole and fixed at both ends to the end plate, of the permanent magnet, The magnetic permeability in the region on the outer peripheral side of the split rotor is lower than the magnetic permeability of the outer peripheral side core piece and the rotary shaft side core piece.
The electric motor of the present invention includes the split-type rotor, and a stator arranged so that an inner periphery thereof is opposed to the outer periphery of the split-type rotor with an interval.

  According to the present invention, the outer iron core piece relatively positioned on the outer peripheral side of the split-type rotor and the rotary iron core piece relatively positioned on the rotary shaft side of the split-type rotor are provided. The core piece coupling member was inserted into the through hole formed in the outer peripheral side core piece, and both ends of the core piece coupling member were fixed to the end plate. Therefore, it is possible to simplify the structure of the outer peripheral side core piece and the rotary shaft side core piece, compared with the case where the core piece coupling member is fitted to the outer peripheral side core piece and the rotary shaft side core piece. Can be easily and reliably coupled. In addition, since the permeability of the permanent magnet in the region on the outer peripheral side of the split rotor is lower than the magnetic permeability of the outer peripheral side core piece and the rotary shaft side core piece, Generation | occurrence | production of a leakage magnetic flux can be suppressed.

1 is a cross-sectional view of an IPM motor according to a first embodiment of the present invention. 1 is a cross-sectional view of a split rotor according to a first embodiment of the present invention. It is a figure which shows the 1st Embodiment of this invention and shows an example of a structure of the outer peripheral side core piece. It is a figure which shows the 1st Embodiment of this invention and shows an example of a structure of the rotating shaft side iron core piece. FIG. 2 is a cross-sectional view of an IPM motor according to a second embodiment of the present invention. FIG. 5 is a cross-sectional view of a split rotor showing a second embodiment of the present invention. It is a figure which shows the 2nd Embodiment of this invention and shows the structure of an outer peripheral side iron core piece. It is a figure which shows the 2nd Embodiment of this invention and shows the structure of a rotating shaft side iron core piece. FIG. 5 is a cross-sectional view of an IPM motor according to a third embodiment of the present invention. FIG. 6 is a cross-sectional view of a split rotor showing a third embodiment of the present invention. It is a figure which shows the 3rd Embodiment of this invention and shows the structure of an outer peripheral side iron core piece. It is a figure which shows the 3rd Embodiment of this invention and shows the structure of a rotating shaft side iron core piece. FIG. 6 is a cross-sectional view of an IPM motor according to a fourth embodiment of the present invention. FIG. 6 is a cross-sectional view of a split rotor showing a fourth embodiment of the present invention. It is a figure which shows the 4th Embodiment of this invention and shows the structure of an outer peripheral side core piece. It is a figure which shows the 4th Embodiment of this invention and shows a mode when an iron core piece coupling member is inserted in the through-hole. FIG. 10 is a cross-sectional view of an IPM motor according to a fifth embodiment of the present invention. FIG. 9 is a cross-sectional view of a split rotor showing a fifth embodiment of the present invention. It is a figure which shows the 5th Embodiment of this invention and shows the structure of an outer peripheral side iron core piece.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
First, a first embodiment of the present invention will be described.
FIG. 1 shows an example of a sectional view when the IPM motor is cut from a direction perpendicular to the rotation axis of the IPM motor, which is an application example of the split rotor. FIG. 2 shows an example of a sectional view of the split rotor when the IPM motor is cut along the rotation axis of the IPM motor. Specifically, FIG. 2 is a cross-sectional view of the split rotor viewed from the AA ′ direction of FIG. In each figure, only the outline of the necessary part is shown for convenience of explanation.
1 and 2, the IPM motor 100 includes a stator (stator) 110, a split-type rotor (rotor) 120, a case 130, a rotating shaft 140, and an end plate 150.

Stator 110 has a yoke extending in the circumferential direction and a plurality of teeth extending in the axial direction from the inner peripheral side of the yoke. The plurality of teeth are provided at substantially equal intervals in the circumferential direction (in the example illustrated in FIG. 1, twelve teeth are provided). Note that windings (not shown) are wound around the teeth.
When the case 130 is shrink-fitted, the stator 110 is fixed in close contact with the stator 110 from the periphery (outer periphery) of the stator 110. The case 130 is made of, for example, a magnetic material such as iron or a nonmagnetic material such as aluminum.

The split rotor 120 includes outer peripheral side iron core pieces 121a to 121d, a rotary shaft side iron core piece 122, iron core piece coupling members 123a to 123d, and permanent magnets 124a to 124h, and is formed by combining these. The
The permanent magnets 124a to 124h have a rectangular parallelepiped shape. As shown in FIG. 1, the permanent magnets 124 a to 124 h are arranged at intervals in the circumferential direction of the split rotor 120. In addition, among the end faces of the permanent magnets 124a to 124h in the circumferential direction of the split-type rotor 120, one end face is relatively positioned on the outer peripheral side of the split-type rotor 120 and the other end face is relatively split-type rotating. It is located on the rotating shaft side of the child 120. At this time, in the circumferential direction of the split-type rotor 120, the end faces relatively positioned on the outer peripheral side of the split-type rotor 120 are adjacent to each other with a space therebetween, and the split-type rotor 120 is relatively positioned. The permanent magnets 124a to 124h are spaced apart from each other in the circumferential direction of the split-type rotor 120 so that the end faces located on the rotating shaft side are adjacent to each other with a spacing therebetween. To be placed.

Of the permanent magnets 124a to 124h arranged in this way, two end surfaces that are relatively positioned on the rotating shaft side of the split rotor 120 are adjacent to each other with a space therebetween. One pole (pole) of the split rotor 120 is formed by permanent magnets (for example, permanent magnets 124a and 124b). In the circumferential direction of the split rotor 120, different poles are alternately present.
In the following description, the outer circumference and the rotation axis are respectively referred to as the outer circumference and the rotation axis of the split rotor 11 unless otherwise specified.

The outer peripheral side core pieces 121 a to 121 d are core pieces that are relatively disposed on the outer peripheral side of the split rotor 120. As shown in FIG. 1, in the present embodiment, outer peripheral core pieces 121 a to 121 d are individually provided for each pole of the split rotor 120.
FIG. 3 is a diagram illustrating an example of the configuration of the outer peripheral iron core piece 121a. More specifically, FIG. 3A is an external view of the outer peripheral core piece 121a viewed from the direction shown in FIG. 1 (the direction along the rotation shaft 140), and FIG. It is sectional drawing of the outer peripheral side iron core piece 121a seen from the AA 'direction of 3 (a). Since the outer peripheral core pieces 121b to 121d other than the outer peripheral core piece 121a have the same configuration as the outer peripheral iron piece 121a, their illustration is omitted.

The outer peripheral iron core piece 121a is formed by stacking a plurality of electromagnetic steel sheets punched into a shape as shown in FIG. 3 (a) in the thickness direction as shown in FIG. 3 (b). However, you may make it form the outer peripheral side iron core piece 121a using magnetic body plates other than an electromagnetic steel plate.
As shown in FIG. 3, the central rotating shaft side region in the circumferential direction of the outer peripheral side core piece 121 a (the region closer to the rotating shaft side than the outer peripheral side of the outer peripheral side core piece 121 a and as close to the rotating shaft side as possible. A through hole 125 for inserting an iron core piece coupling member 123a, which will be described later, is formed in the near area.

The rotating shaft side iron core piece 122 is an iron core piece relatively disposed on the rotating shaft side of the split rotor 120. As shown in FIG. 1, in this embodiment, the single rotating shaft side iron core piece 122 is provided.
FIG. 4 is a diagram illustrating an example of the configuration of the rotating shaft side iron core piece 122. More specifically, FIG. 4A is an external view of the rotating shaft side iron core piece 122 viewed from the direction shown in FIG. 1 (the direction along the rotating shaft 140), and FIG. It is sectional drawing of the rotating shaft side iron core piece 122 seen from the AA 'direction of Fig.4 (a).
As shown in FIG. 4, a through hole 126 for inserting the rotating shaft 140 is formed in the center region of the rotating shaft side iron core piece 122.
The rotating shaft side iron core piece 122 is formed by stacking a plurality of electromagnetic steel plates punched into a shape as shown in FIG. 4A in the thickness direction as shown in FIG. 4B.
As shown in FIG. 1, in the present embodiment, gaps 127a to 127d are formed between the end faces in the circumferential direction of the outer peripheral side core pieces 121a to 121d. In this embodiment, by doing in this way, gaps 127a to 127d are formed in regions on the outer peripheral side relative to the end surfaces relatively positioned on the outer peripheral side among the end surfaces in the circumferential direction of the permanent magnets 124a to 124h. I have to. Therefore, the magnetic permeability of the outer peripheral side region (the gaps 127 a to 127 d) is lower than the magnetic permeability of the outer peripheral side iron core piece 121 and the rotating shaft side iron core piece 122.

  In the present embodiment, the rotary shaft side iron core piece 122 is formed by stacking a plurality of electromagnetic steel plates, but it is not always necessary to do so. For example, the rotating shaft side iron core piece may be integrally formed using a magnetic body (iron or the like) having the same outer shape as that shown in FIG. This is because a DC magnetic flux is generated on the rotating shaft side of the split-type rotor 120 but no high-frequency magnetic flux is generated, and thus the performance of the split-type rotor 120 is not greatly affected.

  The shape of the core piece coupling members 123a to 123d (before processing) is a shape (rectangular shape) matched to the through hole 125 shown in FIG. 3, and the through hole 125 formed in the outer peripheral side core pieces 121a to 121d. Inserted into. Thereafter, as shown in FIG. 2, the one end side and the other end side of the core piece coupling members 123 a to 123 d are processed using eyelets or the like, and the one end and the other end of the core piece coupling members 123 a to 123 d are processed. Are fixed to the end plates 150a and 150b, respectively. The end plates 150 a and 150 b are arranged at both ends in the rotation axis direction of the split-type rotor 110 and are used to stop the split-type rotor 110. The end plates 150a and 150b are formed of a non-magnetic material (or a magnetic material with low magnetic permeability). However, it is not always necessary to do this, and an end plate having only a region close to the permanent magnets 124a to 124h as a non-magnetic material and other regions as magnetic materials may be employed.

In the present embodiment, the core piece coupling members 123a to 123d are formed of a magnetic body (integrally). However, the iron core piece coupling member 123 may be formed of a non-magnetic material (or a magnetic material having a lower magnetic permeability than the outer peripheral iron core piece 121 and the rotating shaft side iron core piece 122).
As described above, the through hole 125 is formed on the rotating shaft side of the outer peripheral core piece 121a (a position far from the outer peripheral surface of the outer peripheral core piece 121a). Therefore, even if a closed circuit (electric circuit) is constituted by the core piece coupling member 123, the end plate 150, and the outer peripheral side core piece 121, the AC magnetic field from the stator 110 interlaces with the closed circuit. Generation of induced electromotive force (induced current) due to can be reduced.
Further, the core piece coupling member 123 has a strength that does not deform due to the centrifugal force generated by the rotation of the split rotor 120.

  In the present embodiment, as described above, even when the split rotor 120 rotates, the outer peripheral side core pieces 121a to 121d are fixed to the end plates 150a and 150b via the core piece connecting members 123a to 123d. Can be done. As a result, even if centrifugal force is generated by the rotation of the split rotor 120, the outer peripheral side core pieces 121a to 121d, the rotary shaft side core pieces 122, the core piece connecting members 123a to 123d, and the permanent magnets 124a to 124h. Can be prevented from separating from each other.

  As described above, in the present embodiment, the outer peripheral side iron core pieces 121a to 121d that are relatively positioned on the outer peripheral side of the split-type rotor 120 and the rotary shaft side that is relatively positioned on the rotary shaft side of the split-type rotor 120. The core of the rotor is divided into the core piece 122, and the core piece coupling members 123a to 123d are inserted into the through holes 125 formed in the outer peripheral side core pieces 121a to 121d, and both ends of the core piece coupling members 123a to 123d are inserted. The end plates 150a and 150b are fixed. Therefore, the outer peripheral side core pieces 121a to 121d and the rotary shaft side core piece 122 can be more securely provided than before without the core piece connecting member being fitted to both the outer peripheral side core piece and the rotary shaft side core piece. Can be combined.

  Further, among the end surfaces in the circumferential direction of the permanent magnets 124a to 124h, the gaps 127a to 127d are formed in the region on the outer peripheral side relative to the end surface relatively positioned on the outer peripheral side. Thus, it is possible to suppress the generation of leakage magnetic flux between the end surfaces on the outer peripheral side of the permanent magnets 124a to 124d and the end surface on the rotating shaft side, and it is possible to suppress the saturation of the iron core due to the leakage magnetic flux. Can also be suppressed. Therefore, it is possible to prevent the magnetic flux generated by the stator 110 and the like from entering the permanent magnets 124a to 124d as much as possible, the temperature of the permanent magnets 124a to 124d is increased, and the permanent magnets 124a to 124d are used as the magnets. It is possible to suppress the lowering of the function of the present invention compared to the conventional case. Thereby, for example, it is not necessary to use a specific material such as neodymium-iron-boron (Ne-Fe-B) with improved heat resistance as the permanent magnets 124a to 124d.

In addition, it is possible to suppress the occurrence of leakage magnetic flux between the end face on the outer peripheral side of the permanent magnets 124a to 124d and the end face on the rotating shaft side, so that the permanent magnets 124a to 124d can be fixed to the stator. It is also possible to increase the magnetic flux transmitted in the direction of 110, and to suppress a decrease in the torque of the IMP motor.
As described above, in this embodiment, an IPM motor with higher performance and higher strength than the conventional one can be easily formed.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. In the first embodiment described above, one core piece coupling member 123 is inserted into the central rotating shaft side region in the circumferential direction of the outer peripheral side core piece 121, and the core piece coupling member 123 is attached to the end plates 150a and 150b. The case of fixing was explained. On the other hand, this embodiment demonstrates the case where two iron core piece coupling members are inserted in an outer peripheral side iron core piece, and these two iron core piece coupling members are fixed to an end plate. As described above, the present embodiment is different from the first embodiment described above mainly in the configuration relating to the outer peripheral side iron core piece and the iron core piece coupling member. Therefore, in the description of the present embodiment, the same parts as those in the first embodiment described above are denoted by the same reference numerals as those in FIGS.

FIG. 5 shows an example of a cross-sectional view when the IPM motor is cut from a direction perpendicular to the rotation axis of the IPM motor, which is an application example of the split rotor. FIG. 6 shows an example of a sectional view of the split rotor when the IPM motor is cut along the rotation axis of the IPM motor. Specifically, FIG. 6 is a cross-sectional view of the split rotor viewed from the AA ′ direction of FIG. In each figure, only the outline of the necessary part is shown for convenience of explanation.
5 and 6, the IPM motor 200 includes a stator (stator) 110, a split-type rotor (rotor) 210, a case 130, a rotating shaft 140, and an end plate 150.

The split-type rotor 210 includes outer peripheral side iron core pieces 211a to 211d, a rotary shaft side iron core piece 212, iron core piece coupling members 213a to 213h, and permanent magnets 124a to 124h, and is formed by combining these. The
The outer peripheral core pieces 211 a to 211 d are iron core pieces that are relatively disposed on the outer peripheral side of the split rotor 210. As shown in FIG. 5, in the present embodiment, outer peripheral side iron core pieces 211 a to 211 d are individually provided for each pole of the split rotor 210.
FIG. 7 is a diagram illustrating an example of the configuration of the outer peripheral side iron core piece 211a. More specifically, FIG. 7A is an external view of the outer peripheral side iron core piece 211a viewed from the direction shown in FIG. 5 (the direction along the rotating shaft 140), and FIG. It is sectional drawing of the outer peripheral side iron core piece 211a seen from the AA 'direction of 7 (a). Since the outer peripheral side core pieces 211b to 211d other than the outer peripheral side core piece 211a have the same configuration as the outer peripheral side core piece 211a, their illustration is omitted.
The outer peripheral side iron core piece 211a is formed by stacking a plurality of electromagnetic steel sheets punched into a shape as shown in FIG. 7A in the thickness direction as shown in FIG. 7B. However, you may make it form the outer peripheral side iron core piece 211a using magnetic body plates other than an electromagnetic steel plate.
As shown in FIG. 7, through-holes 214a and 214b for inserting core piece coupling members 213a and 213b, which will be described later, are formed in regions on both sides in the circumferential direction of the outer peripheral side core piece 211a. 5 and 7, for convenience of description, the through-hole 214a is located at a position where the distance from the outer end surface of the core piece coupling members 213a and 213b and the distance from the end surface on the rotating shaft side are substantially the same. , 214b are formed, but as described in the first embodiment, the through holes 214a, 214b are formed on the rotating shaft side as much as possible so that the influence of the AC magnetic field from the stator 110 is reduced. Is preferred.

The rotating shaft side iron core piece 212 is an iron core piece relatively disposed on the rotating shaft side of the split-type rotor 210. As shown in FIG. 5, in the present embodiment, a single rotating shaft side iron core piece 212 is provided.
FIG. 8 is a diagram illustrating an example of the configuration of the rotating shaft side iron core piece 212. Specifically, FIG. 8A is an external view of the rotating shaft side iron core piece 212 viewed from the direction shown in FIG. 5 (the direction along the rotating shaft 140), and FIG. It is sectional drawing of the rotating shaft side iron core piece 212 seen from the AA 'direction of Fig.8 (a).
As shown in FIG. 8, a through hole 215 for inserting the rotation shaft 140 is formed in the center region of the rotation shaft side iron core piece 212.

The rotating shaft side iron core piece 212 is formed by stacking a plurality of electromagnetic steel plates punched into a shape as shown in FIG. 8A in the thickness direction as shown in FIG. 8B.
And in this embodiment, as shown in FIG. 5, the clearance gaps 216a-216d are formed between the end surfaces of the circumferential direction of the outer peripheral side iron core pieces 211a-211d. In this embodiment, by doing in this way, gaps 216a to 216d are formed in regions on the outer peripheral side relative to the end surfaces relatively positioned on the outer peripheral side among the end surfaces in the circumferential direction of the permanent magnets 124a to 124h. I have to. Therefore, the magnetic permeability of the outer peripheral side region (gap 216a to 216d) is lower than the magnetic permeability of the outer peripheral side iron core piece 211 and the rotary shaft side iron core piece 212.
In the present embodiment, the rotating shaft side iron core piece 212 is formed by stacking a plurality of electromagnetic steel plates, but this is not necessarily required. For example, the rotating shaft side iron core piece may be integrally formed using a magnetic body (iron or the like) having the same outer shape as that shown in FIG.

The shape of the core piece coupling members 213a to 213h (before processing) is a shape (cylindrical shape) that matches the through hole 214 shown in FIG. 7, and the through holes 214 formed in the outer peripheral side core pieces 211a to 211d. Inserted into. After that, as shown in FIG. 6, processing is performed on one end side and the other end side of the core piece coupling member 213, and one end and the other end of the core piece coupling member 213 are fixed to the end plates 150a and 150b, respectively. Is done.
In this embodiment, the iron core piece coupling members 213a to 213h are formed of a magnetic material (integrally). Further, the iron core piece coupling member 213 has a strength that does not deform due to the centrifugal force generated by the rotation of the split rotor 210.

  In this embodiment, by doing in this way, even if the split-type | die rotor 210 rotates, the outer peripheral side iron core pieces 211a-211d are fixed to the end plates 150a, 150b via the iron core piece coupling members 213a-213h. You can make it. Thereby, even if centrifugal force is generated by the rotation of the split-type rotor 210, the outer peripheral side iron core pieces 211a to 211d, the rotary shaft side iron core piece 212, the iron core piece coupling members 213a to 213h, and the permanent magnets 124a to 124h. Can be prevented from separating from each other.

As described above, in this embodiment, the outer peripheral side iron core pieces 211a to 211d that are relatively positioned on the outer peripheral side of the split-type rotor 210 and the rotary shaft side that is relatively positioned on the rotary shaft side of the split-type rotor 210. The rotor core is divided into the core piece 212, and the core piece coupling members 213a to 213h are individually inserted into the through holes 214 formed in each of the outer peripheral side core pieces 211a to 211d. Both ends of the members 213a to 213h are fixed to the end plates 150a and 150b. Thus, since the outer peripheral side iron core pieces 211a-211d can be fixed to the end plates 150a, 150b at two places, the outer peripheral side iron core pieces 121a-121d and the rotating shaft side iron core piece 122 are connected to the first embodiment. It is possible to bond more reliably than the above.
In this embodiment, the outer peripheral core pieces 211a to 211d are fixed to the end plates 150a and 150b at two locations. However, the outer peripheral core pieces are fixed to the end plates 150a and 150b at three or more locations. May be.

(Third embodiment)
Next, a third embodiment of the present invention will be described. In the present embodiment, a case will be described in which the core piece coupling member of the second embodiment described above is attached in a state of being electrically insulated from other members. Thus, the present embodiment is different from the first and second embodiments described above mainly in the configuration in which the iron core piece coupling member is electrically insulated. Therefore, in the description of the present embodiment, the same parts as those in the first and second embodiments described above are denoted by the same reference numerals as those in FIGS. .

FIG. 9 shows an example of a cross-sectional view when the IPM motor is cut from a direction perpendicular to the rotation axis of the IPM motor, which is an application example of the split rotor. FIG. 10 shows an example of a sectional view of the split rotor when the IPM motor is cut along the rotation axis of the IPM motor. Specifically, FIG. 10 is a cross-sectional view of the split rotor viewed from the AA ′ direction of FIG. In each figure, only the outline of the necessary part is shown for convenience of explanation.
9 and 10, the IPM motor 300 includes a stator (stator) 110, a split-type rotor (rotor) 310, a case 130, a rotating shaft 140, and an end plate 150.

The split rotor 310 includes outer peripheral side iron core pieces 311a to 311d, a rotary shaft side iron core piece 312, iron core piece coupling members 313a to 313h, insulating members 314a to 314h, and permanent magnets 124a to 124h. It is formed by combining these.
The outer peripheral core pieces 311 a to 311 d are iron core pieces that are relatively disposed on the outer peripheral side of the split rotor 310. As shown in FIG. 9, in this embodiment, outer peripheral side iron core pieces 311 a to 311 d are individually provided for each pole of the split rotor 310.
FIG. 11 is a diagram illustrating an example of the configuration of the outer peripheral iron core piece 311a. More specifically, FIG. 11A is an external view of the outer peripheral iron core piece 311a viewed from the direction shown in FIG. 9 (the direction along the rotation axis of the split-type rotor 310). FIG. 11B is a cross-sectional view of the outer peripheral core piece 311a viewed from the AA ′ direction in FIG. Since the outer peripheral side core pieces 311b to 311d other than the outer peripheral side core piece 311a have the same configuration as the outer peripheral side core piece 311a, their illustration is omitted.

The outer peripheral side iron core piece 311a is formed by stacking a plurality of electromagnetic steel sheets punched into a shape as shown in FIG. 11 (a) in the thickness direction as shown in FIG. 11 (b). However, you may make it form the outer peripheral side iron core piece 311a using magnetic body plates other than an electromagnetic steel plate.
As shown in FIG. 11, through-holes 315a and 315b for inserting core piece coupling members 313a and 313b, which will be described later, and insulating members 314a and 314b, respectively, are provided in regions on both sides in the circumferential direction of the outer peripheral side core piece 311a. Is formed.

The rotating shaft side iron core piece 312 is an iron core piece relatively disposed on the rotating shaft side of the split rotor 310. As shown in FIG. 9, in this embodiment, a single rotating shaft side iron core piece 312 is provided.
FIG. 12 is a diagram illustrating an example of the configuration of the rotating shaft side iron core piece 312. More specifically, FIG. 12A is an external view of the rotating shaft side iron core piece 312 viewed from the direction shown in FIG. 9 (the direction along the rotating shaft 140), and FIG. It is sectional drawing of the rotating shaft side iron core piece 312 seen from the AA 'direction of Fig.12 (a).
As shown in FIG. 12, a through hole 316 for inserting the rotation shaft 140 is formed in the center region of the rotation shaft side iron core piece 312.

The rotating shaft side iron core piece 312 is formed by stacking a plurality of electromagnetic steel plates punched into a shape as shown in FIG. 12A in the thickness direction as shown in FIG.
And in this embodiment, as shown in FIG. 9, it protrudes in the outer peripheral side rather than the permanent magnets 124a-124h among the end surfaces of the outer peripheral direction of the outer peripheral side iron core pieces 311a-311d, and the end surface of the rotating shaft side iron core piece 312. The outer peripheral side iron core pieces 311a to 311d, the rotary shaft side iron core piece 312 and the permanent magnets 124a to 124h are configured so that gaps 317a to 317h are formed between the end face. In this embodiment, by doing in this way, gaps 317a to 317h are formed in regions on the outer peripheral side of the end surfaces in the outer peripheral direction of the permanent magnets 124a to 124h relative to the end surfaces relatively positioned on the outer peripheral side. I have to. Therefore, the magnetic permeability of the outer peripheral side region (gap 317 a to 317 h) is lower than the magnetic permeability of the outer peripheral side iron core piece 311 and the rotating shaft side iron core piece 312.
In the present embodiment, the rotating shaft side iron core piece 312 is formed by stacking a plurality of electromagnetic steel plates, but this is not necessarily required. For example, the rotating shaft side iron core piece may be integrally formed using a magnetic body (iron or the like) having the same outer shape as that shown in FIG.

The iron core piece coupling members 313a to 313h have a bolt shape (screw shape) matched to the through hole 315 shown in FIG. Further, the insulating members 314a to 314h are formed between the “core piece coupling members 313a to 313h, the end plate 150a, and the outer core piece 311” when the core piece coupling members 313a to 313h are inserted into the through holes 315. It is formed (integrally) by an insulating material processed in accordance with “the shape of”. As shown in FIGS. 9 and 10, the insulating members 314 a to 314 h are inserted into the through holes 315, and the core piece coupling members 313 a to 313 h are inserted into the insulating members 314 a to 314 h inserted into the through holes 315. Note that the insulating members 314a to 314h may be inserted into the through holes 315 in a state where the iron core piece coupling members 313a to 313h are inserted.
In the present embodiment, when the core piece coupling members 313a to 313h are inserted into the through holes 315 in this manner, as shown in FIG. 10, the tips of the core piece coupling members 313a to 313h (tips on the side where the screw threads are located). ) And the end plate 150b are pressed in the direction along the rotation axis 140 at the joint point between the end plate 150b and the core piece coupling members 313a to 314h to be fixed to the end plates 150a and 150b.

  Moreover, in this embodiment, since the iron core piece coupling members 313a to 313h, the end plate 150a and the outer peripheral side iron core piece 311 are electrically insulated by the insulating members 314a to 314h, the iron core piece coupling members 313a to 313h. And the closed circuit (electric circuit) by the outer peripheral side iron core piece 311 and the closed circuit (electric circuit) by the iron core piece coupling member 313, the outer peripheral side iron core piece 311 and the end plate 150 are not formed. Therefore, even if the iron core piece coupling members 313a to 313h are made of a magnetic material (integrally), they are made of a nonmagnetic material (or a magnetic material having a lower permeability than the outer peripheral iron core piece 311 and the rotating shaft iron core piece 312). In). Further, the iron core piece coupling members 313 a to 313 h have a strength that is not deformed by the centrifugal force generated by the rotation of the split rotor 210.

  In this embodiment, by doing in this way, even if the split type rotor 310 rotates, the outer peripheral side iron core pieces 311a to 311d are fixed to the end plates 150a and 150b via the iron core piece coupling members 313a to 313h. You can make it. As a result, even if centrifugal force is generated by the rotation of the split rotor 310, the outer peripheral side core pieces 311a to 311d, the rotary shaft side core pieces 312, the core piece coupling members 313a to 313h, and the permanent magnets 324a to 324h. Can be prevented from separating from each other.

  As described above, in the present embodiment, the outer peripheral side iron core pieces 311a to 311d that are relatively positioned on the outer peripheral side of the split-type rotor 310 and the rotary shaft side that is relatively positioned on the rotary shaft side of the split-type rotor 310. The core piece of the rotor is divided into the core piece 312 and the core piece coupling members 313a to 313h are electrically insulated from the outer peripheral side core pieces 311a to 311d and the end plate 150a by the insulating member 314a. The coupling members 313a to 313h were individually inserted into the through holes 315, and both ends of the iron core piece coupling members 313a to 313h were fixed to the end plates 150a and 150b. Therefore, it is possible to prevent a closed circuit from being formed by the iron core piece coupling member 313, the outer peripheral iron core piece 311 and the end plate 150, and as shown in FIG. Even if the rotating shaft side iron core piece 312 is protruded to the outer peripheral side from the permanent magnets 124a to 124h so as to pass through the iron core piece 312, it is possible to prevent the iron loss of the split rotor 310 from increasing.

In this embodiment, the core piece coupling members 313a to 313h are electrically insulated from the outer peripheral side core pieces 311a to 311d and the end plate 150a. However, this is not always necessary. For example, the iron core piece coupling members 313a to 313h may be electrically insulated from the outer peripheral side iron core pieces 311a to 311d and the end plate 150b, or the iron core piece coupling members 313a to 313h may be electrically insulated from the outer circumference side iron core piece 311a. ˜311d and end plates 150a and 150b may be electrically insulated. That is, if the core piece coupling members 313a to 313h are electrically insulated from other members so as not to form a (electrical) closed circuit including the core piece coupling members 313a to 313h in part. Good.
Further, although the insulating members 314a to 314h are made of an integrally processed insulating material, the insulating members 314a to 314h are molded between the core coupling members 313a to 313h and the through-holes 315 even if formed by a combination of a plurality of processed insulating materials. Insulating material such as resin formed in such a manner, insulating material coated in advance on the iron core coupling members 313a to 313h, insulating material coated in close contact on the wall surface of the through hole 315 Good.
Moreover, you may make it fix an outer peripheral side iron core piece to the end plates 150a and 150b in three or more places.
Moreover, you may make it apply an insulation member like this embodiment with respect to the iron core piece coupling member 123 demonstrated in 1st Embodiment.

(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described. In this embodiment, a case where the direction in which the magnetic flux flows is controlled by the iron core piece coupling member will be described. As described above, the present embodiment is different from the first to third embodiments described above mainly in the configuration in which the direction in which the magnetic flux flows is controlled by the core piece coupling member. Therefore, in the description of the present embodiment, the same parts as those in the first to third embodiments described above are denoted by the same reference numerals as those in FIGS. .

FIG. 13 shows an example of a cross-sectional view when the IPM motor is cut from a direction perpendicular to the rotation axis of the IPM motor, which is an application example of the split rotor. FIG. 14 shows an example of a sectional view of the split rotor when the IPM motor is cut along the rotation axis of the IPM motor. Specifically, FIG. 14 is a cross-sectional view of the split rotor viewed from the AA ′ direction of FIG. In each figure, only the outline of the necessary part is shown for convenience of explanation.
13 and 14, the IPM motor 400 includes a stator (stator) 110, a split-type rotor (rotor) 410, a case 130, a rotating shaft 140, and an end plate 150.

The split-type rotor 410 includes outer peripheral side iron core pieces 411a to 411d, a rotary shaft side iron core piece 122, iron core piece coupling members 413a to 413t, and permanent magnets 124a to 124h, and is formed by combining these. The
The outer peripheral side iron core pieces 411 a to 411 d are iron core pieces that are relatively disposed on the outer peripheral side of the split-type rotor 410. As shown in FIG. 13, in this embodiment, outer peripheral side core pieces 411 a to 411 d are individually provided for each pole of the split rotor 410.
FIG. 15 is a diagram illustrating an example of the configuration of the outer peripheral iron core piece 411a. Specifically, FIG. 15A is an external view of the outer peripheral core piece 411a viewed from the direction shown in FIG. 13 (the direction along the rotation axis of the split-type rotor 410), and FIG. FIG. 15B is a cross-sectional view of the outer peripheral core piece 411a viewed from the AA ′ direction in FIG. Since the outer peripheral side core pieces 411b to 411d other than the outer peripheral side core piece 411a have the same configuration as the outer peripheral side core piece 411a, their illustration is omitted.

The outer peripheral side iron core piece 411a is formed by stacking a plurality of electromagnetic steel sheets punched into a shape as shown in FIG. 15 (a) in the thickness direction as shown in FIG. 15 (b). However, you may make it form the outer peripheral side iron core piece 411a using magnetic body plates other than an electromagnetic steel plate.
As shown in FIG. 15, in the circumferential direction of the outer peripheral side core piece 411a, through holes 414a to 414e for inserting core piece coupling members 413a to 413e described later are formed at intervals. In the present embodiment, “between the through holes 414a to 414e,“ from the rotation axis side of the outer peripheral side core piece 411a (lower side of FIG. 15A) to the outer side of the outer peripheral side core piece 411a (upper side of FIG. 15A). The through-holes 414a to 414e are formed so that the “path to)” is directed to the central portion in the circumferential direction of the outer peripheral iron core piece 411a.

Moreover, in this embodiment, the iron core piece coupling members 413a to 413t are formed of a non-magnetic material (or a magnetic material having a lower permeability than the outer peripheral side iron core piece 411 and the rotating shaft side iron core piece 122). Moreover, the shape (before processing) of the core piece coupling members 413a to 413t is a rectangular parallelepiped shape as described in the first embodiment, and the through holes 414a to 414t formed in the outer peripheral side core pieces 411a to 411d. Inserted into. Thereafter, as shown in FIG. 14, each of the one end side and the other end side of the core piece coupling members 413 a to 413 t is processed using eyelets or the like, and one end and the other end of the core piece coupling members 413 a to 413 t are processed. Are fixed to the end plates 150a and 150b, respectively.
16 is a diagram (an enlarged view of a portion of the core piece coupling member 413a in FIG. 13) showing an example of the state when the core piece coupling member 413a is inserted into the through hole 414a. The state when the core piece coupling members 413b to 413t other than the core piece coupling member 413a are inserted into the through holes 414b to 414t is the state when the core piece coupling member 413a is inserted into the through hole 414a. Since they are the same, their illustration is omitted.

  As shown in FIG. 16, in this embodiment, the length of the core piece coupling member 413a and the length of the through hole 414a are substantially the same in the radial direction of the split-type rotor 410 (direction a in FIG. 16). However, in the circumferential direction (the b direction in FIG. 16), the length of the through hole 414a is made larger than the length of the core piece coupling member 413a, and a gap is formed between the core piece coupling member 413a and the outer peripheral side core piece 411a. I am trying to provide it. By forming such a gap, it is possible to prevent the alternating magnetic flux from flowing in the circumferential direction of the core piece coupling member 413a (the alternating magnetic flux from the stator 110 flows to the core piece coupling member 413a).

  In this embodiment, by doing in this way, even if the split type rotor 410 rotates, the outer peripheral side iron core pieces 411a to 411d are fixed to the end plates 150a and 150b via the iron core piece coupling members 413a to 413r. You can make it. As a result, even if centrifugal force is generated by the rotation of the split rotor 410, the outer peripheral side iron core pieces 411a to 411d, the rotary shaft side iron core piece 122, the iron core piece coupling members 413a to 413r, and the permanent magnets 124a to 124h. Can be prevented from separating from each other. As shown in FIG. 13, in this embodiment, gaps 415 a to 415 d are formed between the circumferential end surfaces of the outer peripheral side core pieces 411 a to 411 d. In this embodiment, by doing in this way, gaps 415a to 415d are formed in regions on the outer peripheral side relative to the end surfaces relatively positioned on the outer peripheral side among the end surfaces in the circumferential direction of the permanent magnets 124a to 124h. I have to. Therefore, the magnetic permeability of the outer peripheral region (gap 415 a to 415 d) is lower than the magnetic permeability of the outer peripheral side iron core piece 411 and the rotating shaft side iron core piece 122.

As described above, in the present embodiment, the outer peripheral side iron core pieces 411a to 411d relatively positioned on the outer peripheral side of the split-type rotor 410 and the rotary shaft side relatively positioned on the rotary shaft side of the split-type rotor 410. The rotor core is divided into core pieces 122. And five through-holes 414 which face the direction of the center part in the circumferential direction of the outer peripheral surface of outer peripheral side core piece 411a-411d are formed in each of these outer peripheral side core pieces 411a-411d at intervals in the said circumferential direction. The core piece coupling members 413a to 413r were individually inserted into the five through holes 414, and both ends of the core piece coupling members 413a to 413r were fixed to the end plates 150a and 150b. Therefore, in addition to reliably connecting the outer peripheral side core pieces 421a to 421d and the rotary shaft side core piece 122, the DC magnetic field from the permanent magnets 124a to 124h is applied to the outer peripheral surface of the outer peripheral side core pieces 411a to 411d. The DC magnetic field generated by the permanent magnets 124a to 124h can be efficiently transmitted.
Further, in the circumferential direction, since a gap is provided between the iron core piece coupling member 413 and the outer peripheral side iron core piece 411, it is possible to reduce the flow of AC magnetic flux from the stator 110 to the iron core piece coupling member 413a. Can do.

In addition, the number of the through-holes 414 formed in one outer peripheral side iron core piece 421a-421d is not limited to five, As long as it is two or more, any number may be sufficient.
Moreover, you may make it apply an insulation member like 3rd Embodiment with respect to the iron core piece coupling member 413 of this embodiment.
Also in the first to third embodiments, a gap may be formed between the iron core piece coupling member and the outer peripheral iron core piece as in this embodiment.
Moreover, in each embodiment mentioned above, the shape of the iron core piece coupling member 123, 213, 313, 413 is not limited to what was mentioned above. For example, instead of the core piece coupling member 313 described in the third embodiment, the core piece coupling member 213 described in the second embodiment may be used, or the core piece coupling described in the first embodiment may be used. Instead of the member 123, the core piece coupling member 213 described in the second embodiment may be used.

(Fifth embodiment)
Next, a fifth embodiment of the present invention will be described. This embodiment demonstrates the case where the 2nd core piece coupling member which connects the outer peripheral side iron core piece mutually adjacent | abutted in the circumferential direction with respect to 1st Embodiment is provided. As described above, the present embodiment and the first embodiment are mainly different in configuration by providing the second iron core piece coupling member. Therefore, in the description of the present embodiment, the same parts as those in the first embodiment described above are denoted by the same reference numerals as those in FIGS.

FIG. 17 shows an example of a cross-sectional view when the IPM motor is cut from a direction perpendicular to the rotation axis of the IPM motor, which is an application example of the split rotor. FIG. 18 shows an example of a sectional view of the split rotor when the IPM motor is cut along the rotation axis of the IPM motor. Specifically, FIG. 18 is a cross-sectional view of the split rotor viewed from the AA ′ direction in FIG. In each figure, only the outline of the necessary part is shown for convenience of explanation.
17 and 18, the IPM motor 500 includes a stator (stator) 110, a split-type rotor (rotor) 510, a case 130, a rotating shaft 140, and an end plate 150.

The split-type rotor 510 includes outer peripheral side iron core pieces 511a to 511d, a rotary shaft side iron core piece 122, iron core piece coupling members 123a to 123d, second iron core piece coupling members 512a to 512d, and permanent magnets 124a to 124h. It is formed by combining these.
The outer peripheral core pieces 211 a to 211 d are iron core pieces that are relatively disposed on the outer peripheral side of the split rotor 210. As shown in FIG. 5, in the present embodiment, outer peripheral side iron core pieces 211 a to 211 d are individually provided for each pole of the split rotor 210.
FIG. 19 is a diagram illustrating an example of the configuration of the outer peripheral iron core piece 511a. More specifically, FIG. 19A is an external view of the outer peripheral core piece 511a viewed from the direction shown in FIG. 17 (the direction along the rotation shaft 140), and FIG. It is sectional drawing of the outer peripheral side iron core piece 511a seen from the AA 'direction of 17 (a). Since the outer peripheral side core pieces 511b to 511d other than the outer peripheral side core piece 511a have the same configuration as the outer peripheral side core piece 511a, their illustration is omitted.

The outer peripheral side iron core piece 511a is formed by stacking a plurality of electromagnetic steel sheets punched into a shape as shown in FIG. 19 (a) in the thickness direction as shown in FIG. 19 (b). However, you may make it form the outer peripheral side iron core piece 511a using magnetic body plates other than an electromagnetic steel plate.
As shown in FIG. 19, a through-hole 514 for inserting the core piece coupling member 123a is formed in the central rotation axis side region in the circumferential direction of the outer peripheral side core piece 511a. The through hole 514 is the same as that described in the first embodiment (see the through hole 125 in FIG. 3). Further, holes 513a and 513b for fitting second core piece coupling members 512a and 512d, which will be described later, are formed at both ends in the circumferential direction of the outer peripheral side core piece 511a.

The second iron core piece coupling member 51 is formed of a non-magnetic material having a rectangular parallelepiped shape (or a magnetic material having a lower magnetic permeability than the outer peripheral side iron core piece 511 and the rotating shaft side iron core piece 122), and in the circumferential direction. The outer peripheral core pieces 511 (for example, outer peripheral core pieces 511a and 511b) adjacent to each other are fitted in holes 513 formed in the circumferential direction. The length in the circumferential direction of the second core piece coupling member 511 is substantially equal to the length between the bottoms of the two holes 513 formed at the circumferential ends of the outer peripheral side core pieces 511 adjacent to each other in the circumferential direction. Have the same length. In this way, when the second core piece coupling member 511 is fitted in the hole 513, it is possible to prevent the outer peripheral side core pieces 511 adjacent to each other in the circumferential direction from moving in the circumferential direction as much as possible. it can.
Thus, in the present embodiment, for example, the circumferential movement of the split-type rotor 510 (outer peripheral side core piece 511) is mainly prevented by the second core piece coupling member 511, and the movement in the radial direction is mainly caused by the iron core. By preventing by the piece coupling member 511, the outer peripheral side iron core piece 511 and the rotating shaft side iron core piece 122 can be more reliably joined. Moreover, since the 2nd iron core piece coupling member 511 is a rectangular parallelepiped shape, the high precision is not requested | required for the process of each member.

Of the end faces in the circumferential direction of the permanent magnets 124a to 124h, two outer peripheral core pieces 511 that are areas on the outer peripheral side relative to the end faces relatively positioned on the outer peripheral side and are adjacent to each other in the circumferential direction. For example, the second core piece coupling member may be disposed in the entire region between the outer peripheral side core pieces 511a and 511b.
Moreover, you may make it apply a 2nd core piece coupling | bond member to this division | segmentation type | mold rotor 210-410 demonstrated in 2nd-4th embodiment like this embodiment.
Further, the shape of the second core piece coupling member is not limited to the rectangular parallelepiped shape as long as it can be fitted to the outer peripheral side core pieces 511 adjacent to each other in the circumferential direction. However, it is desirable that the shape of the second core piece coupling member is as simple as possible in consideration of the processing accuracy of each member.

In each of the above-described embodiments, the IPM motor has been described as an example of the electric motor. However, the above-described embodiments can be applied even to an electric motor or a generator other than the IPM motor.
Further, in each of the above-described embodiments, a case where a plurality of outer peripheral core pieces are arranged at intervals of one per pole (pole) formed by permanent magnets in the outer peripheral direction of the split rotor. Explained with an example. However, if the magnetic path that attempts to pass through the side of the end face in the outer peripheral direction of the permanent magnet is blocked by a gap or a nonmagnetic material, the outer peripheral core piece is a pole (pole) formed by the permanent magnet. There may be more than one for each.

  It should be noted that the embodiments of the present invention described above are merely examples of implementation in carrying out the present invention, and the technical scope of the present invention should not be construed as being limited thereto. Is. That is, the present invention can be implemented in various forms without departing from the technical idea or the main features thereof.

100, 200, 300, 400, 500 IPM motor 110 Stator
120, 210, 310, 410, 510 Split type rotor (rotor)
121, 211, 311, 411, 511 Outer peripheral core pieces 122, 212, 312 Rotating shaft side core pieces 123, 213, 313, 413 Iron core piece coupling members 124 Permanent magnet 130 Case 140 Rotating shaft 150 End plate 314 Insulating member 512 First 2 core piece coupling member

Claims (7)

An outer peripheral core piece relatively disposed on the outer peripheral side;
A rotating shaft side iron core piece relatively disposed on the rotating shaft side;
Between the outer peripheral side iron core piece and the rotary shaft side iron core piece, a plurality of permanent magnets arranged at intervals in the circumferential direction;
Two end plates arranged at both ends in the rotation axis direction,
A split-type rotor in which a through-hole in the rotation axis direction is formed in the outer peripheral side iron core piece,
Having an iron core piece coupling member inserted into the through hole and fixed at both ends to the end plate;
The permeability of the permanent magnet in a region on the outer peripheral side of the end surface on the outer peripheral side of the split rotor is lower than the magnetic permeability of the outer peripheral side core piece and the rotary shaft side core piece. Split rotor.   2. The split-type rotor according to claim 1, wherein the through hole is formed at a position closer to a rotating shaft side of the outer peripheral side core piece than to an outer peripheral side of the outer peripheral side core piece.   The insulating member disposed between the core piece coupling member inserted into the through hole, at least one of the two end plates, and the outer peripheral core piece. 2. The split rotor according to 2.   The split rotor according to any one of claims 1 to 3, wherein a plurality of the through holes are formed in the outer peripheral iron core piece. The permeability of the core piece coupling member is lower than the permeability of the outer peripheral side core piece and the rotary shaft side core piece,
The plurality of through holes are arranged at intervals in the circumferential direction of the outer peripheral side iron core piece,
The plurality of through-holes are formed such that the region between the plurality of through-holes is directed from the rotation shaft side of the outer peripheral side core piece toward the center in the circumferential direction of the outer peripheral side core piece. The split rotor according to claim 4, wherein   The split rotor according to claim 5, wherein a gap is formed between the outer peripheral iron core piece and the iron core piece coupling member in a circumferential direction of the split rotor. The split rotor according to any one of claims 1 to 6,
An electric motor comprising: a stator disposed so that an inner periphery thereof is opposed to an outer periphery of the split-type rotor with a space therebetween.

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