JPH10336927A - Rotor structure for permanent-magnet synchronous rotary electric machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotor structure for permanent-magnet synchronous rotary electric machine which can be reduced in cost of size (increased in torque per piling margin) and increased in speed, by making the structure simpler without requiring any nonmagnetic material for reinforcement and permanent magnet for magnetic insulation. SOLUTION: A rotor structure is constituted in such a way that a first core section (a) is provided between rotor slots 12b positioned between each pole of a rotor 11 and the outer peripheral surface of a rotor core 12, adjacent slots 12d for magnet between each pole of the rotor 11 are connected to each other. A second core section (b) is provided between first projecting sections 12d-1 formed on the outer periphery side of the connecting section and second projecting sections 12b-1 formed on the inner periphery side of the slots 12b positioned between each pole of the rotor 11. A third core section (c) is provided between the slots for magnet at each magnetic pole of the rotor 11. The first, the second, and the third core sections (a), (b), and (c) are constituted in such a way that the sections can be easily saturated magnetically and can have such sizes that can support a rotating centrifugal force and can make torque transmission. In addition, the first core section (a) is formed to meet a relation, a1>a2, and the second core section (b) is formed at the center to meet a relation, b4/(2 × thickness of permanent magnet) = coercive force of permanent magnet/ saturated magnetic field of steel plate), and then, the third core section (c) is formed to meet a relation, 2×c1<c2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotor structure of a permanent magnet type synchronous rotating electric machine, and more particularly, to a permanent magnet type synchronous rotating electric machine which can be used as an electric motor which starts as an induction machine at the time of starting and operates as a synchronous machine at rated operation. Rotor structure.

[0002]

2. Description of the Related Art FIG. 4A is a cross-sectional view showing a rotor structure of a conventional permanent magnet type synchronous rotating electric machine, and FIG. 4B is a longitudinal sectional view showing a lower half of the rotor structure omitted. It is.

As shown in FIGS. 4 (a) and 4 (b), a rotor core 2 is provided through a gap inside an armature (stator) core (not shown), and a large number of electromagnetic iron plates (steel plates) are provided. 2a
Are laminated in the axial direction. In the electromagnetic iron plate 2a (that is, the rotor core 2), rotor slots 2b are formed at equal intervals in the circumferential direction of the rotor core for each magnetic pole of the rotor 1, and are positioned between the poles of the rotor 1. A magnet slot 2c is formed. The outer peripheral side portion 2d and the inner peripheral side portion 2e of each magnet slot 2c are separated to magnetically insulate the respective poles of the rotor 1. That is, the rotor 1 in the illustrated example has four poles, and the electromagnetic iron plate 2a is divided into four parts according to this.

[0004] Therefore, since the strength against the rotational centrifugal force is low in this state, stainless steel (SUS) plates 7 are interposed at predetermined intervals in the axial direction between the rotor cores 2. Strength against rotational centrifugal force is reinforced.

[0005] The rotor slots 2b are provided with aluminum conductors 3 as secondary conductors by aluminum die casting. Both ends of these aluminum conductors 3 in the axial direction are short-circuited by end rings 8. That is, it is formed in a cage shape by the aluminum conductor 3 and the end ring 8. A permanent magnet (ferrite) 4 is inserted into the magnet slot 2c. These permanent magnets 4 are inserted into the magnet slots 2c such that the directions of the N and S poles are along the circumferential direction of the rotor core and the magnetic poles of the adjacent permanent magnets 4 are the same. This constitutes the magnetic poles (four poles) of the rotor 1.

A shaft 6 as a rotating shaft is fitted and fixed to the inner peripheral portion of the rotor core 2.
A permanent magnet 5 is provided between the rotor 1 and the inner peripheral portion of the rotor core 2 for each magnetic pole of the rotor 1. These permanent magnets 5 are provided for magnetically insulating between the rotor core 2 and the shaft 6.

Therefore, in the permanent magnet type synchronous rotating electric machine provided with the rotor 1 having the above structure, an induced electromotive force is generated in the aluminum conductor 3 by the rotating magnetic field of the stator, and a current flows, thereby generating torque. The rotor 1 starts to rotate. That is,
It can be started as an induction machine. After the rotor 1 is accelerated to near the synchronous speed, the permanent magnet 4 can be used to operate as a synchronous machine.

[0008]

However, the rotor structure of the conventional permanent magnet type synchronous rotating electric machine has the following problems.

Since the electromagnetic iron plate 2 a that generates torque and the nonmagnetic SUS plate 7 that does not generate torque are alternately laminated in the axial direction, the torque / loading ratio is low. In addition, since the electromagnetic iron plate 2a and the SUS plate 7 are alternately laminated, the production is troublesome and the work time is increased. Because of the structure in which the strength against the rotational centrifugal force is indirectly reinforced by the SUS plate 7, there is a limit in increasing the speed of the rotor 1. Since the SUS plate 7 is more expensive than the electromagnetic iron plate 2b, it causes a cost increase. Further, since the permanent magnet 5 must be provided between the rotor core 2 and the shaft 6 for magnetic insulation, the structure is complicated and the number of parts is large, which also causes an increase in cost.

Therefore, in view of the above prior art, the present invention has a simple structure without the need for a non-magnetic material for reinforcement or a permanent magnet for magnetic insulation, and achieves cost reduction, high speed, and miniaturization (torque per load allowance). It is an object of the present invention to provide a rotor structure of a permanent magnet type synchronous rotating electric machine capable of increasing the number.

[0011]

Means for Solving the Problems A first method for solving the above problems is described below.
A rotor structure of a permanent magnet type synchronous rotating electric machine according to the present invention is provided by providing a rotor core, a secondary conductor provided in a rotor slot formed in the rotor core, and a magnet slot formed in the rotor core. A rotor structure of a synchronous rotating electric machine comprising: a permanent magnet constituting a magnetic pole of a rotor; and a rotating shaft fitted and fixed to an inner peripheral portion of the rotor core, wherein the rotor slot is provided around the rotor core. Formed at substantially equal intervals along the direction, and has a size that is easily magnetically saturated and can support the rotating centrifugal force between the rotor slot located between each pole of the rotor and the outer peripheral surface of the rotor core. The magnet slots are formed at substantially equal intervals along the circumferential direction of the rotor core inside the rotor slots in the radial direction of the rotor core relative to the rotor slots. Then, adjacent magnet slots are connected to each other, and a first A magnetic saturation is easily generated between the first convex portion and the second convex portion formed on the inner peripheral side of the rotor slot located between the poles of the rotor, and the rotational centrifugal force is supported. It has a second core portion of a possible size, is easily magnetically saturated between the magnet slots in each magnetic pole of the rotor, can support the rotational centrifugal force, and has a torque to the rotating shaft. It is characterized in that it has a third core portion large enough to withstand transmission.

Further, the rotor structure of the permanent magnet type synchronous rotating electric machine according to the second aspect of the present invention is the rotor structure of the permanent magnet type synchronous rotating electric machine according to the first aspect of the present invention, wherein the width of the first iron core portion in the radial direction of the rotor core is reduced. The width of the core portion between the other rotor slot and the outer peripheral surface of the rotor core is made wider than the width in the radial direction of the rotor core, and the tensile stress acting on the second core portion by the rotational centrifugal force is averaged. It is characterized by having comprised so that.

A rotor structure of a permanent magnet type synchronous rotating electric machine according to a third aspect of the present invention is the rotor structure of the permanent magnet type synchronous rotating electric machine according to the first or second aspect of the present invention, wherein the second core portion has a first convex portion. It is characterized by being located at the center between the base end and the base end of the second projection.

A rotor structure of a permanent magnet type synchronous rotating electric machine according to a fourth aspect of the present invention is the rotor structure of the second core portion in the rotor structure of the permanent magnet type synchronous rotating electric machine according to the first, second or third aspect. The width b4 in the circumferential direction of the iron core is characterized in that it satisfies the following relationship: b4 / (2 × thickness of permanent magnet) = coercive force of permanent magnet / saturated magnetic field of iron plate.

Further, the rotor structure of the permanent magnet type synchronous rotating electric machine according to the fifth invention is the rotor structure of the permanent magnet type synchronous rotating electric machine according to the first, second, third or fourth invention. Has a substantially triangular shape whose width in the circumferential direction of the rotor core gradually decreases from the outer peripheral side to the inner peripheral side of the rotor core.

A rotor structure of a permanent magnet type synchronous rotating electric machine according to a sixth aspect of the present invention is the rotor structure of the permanent magnet type synchronous rotating electric machine according to the fifth aspect of the present invention. The width in the direction is set to be at least twice as large as the width in the circumferential direction of the rotor core at the inner peripheral side of the third core.

Therefore, according to the rotor structure of the permanent magnet type synchronous rotating electric machine of the first invention, the first, second and third cores are easily magnetically saturated and the gap between the poles is magnetically insulated. Thus, the magnetic poles of the rotor are configured. That is, there is no need to separate the rotor core in the circumferential direction or provide a permanent magnet for magnetic insulation. In addition, the rotor core is an integral unit connected at the first core part, the second core part, and the third core part, and the first core part, the second core part, and the third core part are all rotational centrifugal forces. It is not necessary to provide a non-magnetic material for reinforcement because it has a size capable of supporting the non-magnetic material.

Further, according to the rotor structure of the permanent magnet type synchronous rotating electric machine of the second invention, the width of the first iron core portion in the radial direction of the rotor iron core is set to the other rotor slot and the outer circumference of the rotor iron core. By making the width of the core portion between the surface and the surface larger than the width in the radial direction of the rotor core, the tensile stress acting on the second core portion by the rotational centrifugal force is averaged. The mechanical holding force is effectively exerted.

Further, according to the rotor structure of the permanent magnet type synchronous rotating electric machine of the third aspect of the present invention, the second iron core is located at the center between the base end of the first protrusion and the base end of the second protrusion. By being located, partial stress concentration in the second core portion is most relieved.

Further, according to the rotor structure of the permanent magnet type synchronous rotating electric machine of the fourth invention, the width b4 of the second core portion in the circumferential direction of the rotor core is set to a dimension satisfying the following relationship. Therefore, the demagnetizing force applied to the permanent magnet does not become excessive, and the optimal value does not cause a decrease in generated torque.

B4 / (2 × thickness of permanent magnet) = coercive force of permanent magnet / iron plate saturation magnetic field

Further, according to the rotor structure of the permanent magnet type synchronous rotating electric machine according to the fifth or sixth aspect of the present invention, the width of the third core portion in the circumferential direction of the rotor core is changed from the outer peripheral side to the inner peripheral side of the rotor core. By adopting a substantially triangular shape that gradually decreases toward, the structure has a mechanical strength that is hardly deformed and can withstand a fluctuating torque and the like due to disturbance, and is easily magnetically saturated in a narrow portion. In particular, the effect is remarkable when the width in the circumferential direction of the rotor core at the outer peripheral side of the third core is set to be twice or more the width in the circumferential direction of the rotor core at the inner peripheral side of the third core. Becomes

[0023]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a transverse sectional view showing a rotor structure of a permanent magnet type synchronous rotating electric machine according to an embodiment of the present invention, FIG. 2 is a partially enlarged view of FIG. 1, and FIG. 3 is a rotor shown in FIG. FIG. 4 is an explanatory view of a tensile stress acting on the iron core portion of FIG.

<Structure> In FIG. 1, reference numeral 12 denotes a rotor core. The rotor core 12 is provided through an air gap inside an armature (stator) core (not shown) and has a large number of electromagnetic iron plates (steel plates). ) 12a are laminated in the axial direction. Although the details will be described later, the rotor core 12 is not separated in the circumferential direction but is integral, and the rotor core 12 itself can directly support the rotational centrifugal force. SUS for reinforcement like conventional in the middle of
No boards are interposed.

As shown in FIG. 1 and FIG.
a (that is, the rotor core 12) has a rotor slot 12
b, 12c and a magnet slot 12d are formed.

The rotor slots 12b and 12c are formed at substantially equal intervals along the circumferential direction of the rotor core.
1 between the rotor slot 12b located between the respective poles (indicated by a chain line in the figure) and the outer peripheral surface of the rotor core 12.
It has an iron core a. In addition, other rotor slots 12
An iron core a ′ is also provided between c and the outer peripheral surface of the rotor iron core 12.

The magnet slot 12d is the rotor slot 1.
It is formed at substantially equal intervals along the circumferential direction of the rotor core inside the rotor core radial direction relative to 2b and 12c. Moreover,
Adjacent magnet slots 12d between the poles of the rotor 11
Are connected to each other, and the first protrusion 12
d-1 is formed. On the other hand, a second convex portion 12b-1 is formed on the inner peripheral side of the rotor slot 12b located between the poles of the rotor 11. And the first convex portion 12d
-1 and the second convex portion 12b-1 have a second core portion b.

A third iron core c is provided between the magnet slots 12d of each magnetic pole of the rotor 11.

The rotor slots 12b and 12c are provided with aluminum conductors 13 as secondary conductors by aluminum die casting, and both ends in the axial direction of these aluminum conductors 13 are short-circuited by end rings (not shown).
That is, it is formed in a cage shape by the aluminum conductor 13 and the end ring. A permanent magnet 14 is inserted into the magnet slot 12d. These permanent magnets 14 are N,
The direction of the south pole is along the radial direction of the rotor core and is inserted into each magnet slot 12d such that the direction of the magnetic flux changes for every two permanent magnets 14 (that is, for each magnetic pole of the rotor 11). The magnetic force forms the magnetic poles (four poles) of the rotor 11. A shaft 16 made of a ferromagnetic material, which is a rotating shaft, is fitted and fixed to the inner peripheral portion of the rotor core 12 by flaps or the like.

The first iron core a, the second iron core b, and the third iron core c are all easily magnetically saturated because the magnetic poles of the rotor 11 are formed by magnetically insulating between the poles. In addition, it has a size capable of supporting the rotational centrifugal force.
Further, the torque generated on the outer periphery of the aluminum conductor 13 and the rotor core 12 is transmitted to the inner periphery of the rotor core 12 via the third core c, and further transmitted to the shaft 16.
The third iron core c has a size having a mechanical strength that can withstand this torque transmission.

The width a1 of the first core portion a in the radial direction of the rotor core is equal to the width a1 of the rotor core portion a 'between the other rotor slot 12c and the outer peripheral surface of the rotor core 12 in the radial direction of the rotor core. The width is wider than a2, and the second
The tensile stress acting on the iron core b is averaged.

That is, the dimension of the width a2 of the core part a 'is usually about 0.2 to 0.8 mm, and the aluminum conductor (secondary conductor)
13 is set to a size that does not increase the reactance. The first core part a performs the same function as above, but even if only the width a1 of the four first core parts a is widened, the influence on the overall torque characteristics is small. Therefore, as described above, the width a1 of the first core portion a is made larger than the width a2 of the core portion a 'so that the tensile stress acting on the second core portion b by the rotational centrifugal force is averaged. .

As shown in FIG. 3A, when the size of a1 is small, the rotor slot 12b
The tensile stress concentrates on the outer peripheral side portion of the second iron core b (i.e., at the tip (lower end in the figure) of the second convex portion 12b-1). A non-uniform distribution results. On the other hand, as shown in FIG.
Is increased, the tensile stress due to the rotational centrifugal force acts on the entire second iron core portion b and is averaged.

Further, as shown in FIG. 2, the second core portion b extends from the base end (lower end in the figure) of the first protrusion 12d-1 to the second protrusion 1d.
It is located at the center of b5 until the base end (upper end in the figure) of 2b-1.

The width b4 of the second core portion b in the circumferential direction of the rotor core must be set so that the demagnetizing force applied to the permanent magnet 14 does not become excessively large. Decrease. So the dimension of b4 is
Assuming that the thickness of the permanent magnet 14 is MH, the size is set to satisfy the following equation (1).

B4 / (2 × thickness of permanent magnet MH) = coercive force of permanent magnet / saturated magnetic field of iron plate (1)

The third core portion c is a portion connecting the outer peripheral side and the inner peripheral side of the rotor core 12, but since it is magnetically a short circuit, it is easily magnetically saturated and magnetically insulated. It is better to be as small as possible. On the other hand, in terms of mechanical strength, the third iron core portion c needs to have strength capable of supporting the rotational centrifugal force as described above and withstanding torque transmission.

Therefore, the third core portion c is formed in a substantially triangular shape whose width in the circumferential direction of the rotor core gradually decreases from the outer peripheral side to the inner peripheral side of the rotor core. Also, the third iron core c
The width c2 in the circumferential direction of the rotor core at the outer peripheral side of
The width c2 of the rotor core in the circumferential direction at the inner peripheral side of the core c.
(2 × c1 <c2).

<Operation / Effect> In the permanent magnet type synchronous rotating electric machine provided with the rotor 11 having the above structure, the induced electromotive force is generated in the aluminum conductor 13 by the rotating magnetic field of the stator, and the current flows, so that the torque is reduced. Then, the rotor 11 starts to rotate. That is, it can be started as an induction machine. Also,
After the rotor 1 is accelerated to near the synchronous speed, the permanent magnet 14
With this, it can be operated as a synchronous machine.

According to the rotor 11 having the above structure,
The first iron core a, the second iron core b, and the third iron core c are easily magnetically saturated and the gaps are magnetically insulated, so that the magnetic poles of the rotor 11 are configured. That is, there is no need to separate the rotor core 12 in the circumferential direction or provide a permanent magnet for magnetic insulation. Moreover, the electromagnetic iron plate 12a (that is, the rotor core 12) is an integral unit connected at the first core part a, the second core part b, and the third core part c, and the first core part a and the second core part are connected. Since both the portion b and the third core portion c have a size capable of supporting the rotational centrifugal force, there is no need to provide a nonmagnetic material for reinforcement.

Therefore, the structure can be simplified and the cost can be reduced, and the speed can be increased and the size can be reduced (the torque per load can be increased).

Further, the width a1 in the radial direction of the rotor core at the first core portion a is set to be equal to the other rotor slots and the rotor core 1
By making the width of the core a ′ between the outer core 2 and the outer peripheral surface larger than the width a2 in the radial direction of the rotor core, the tensile stress acting on the second core b by the rotational centrifugal force is averaged. Thereby, the mechanical holding force is effectively exerted in the second core portion b.

In other words, in order to achieve magnetic saturation, the width b2 (see FIG. 2) of the second core portion b in the circumferential direction of the rotor core is preferably as small as possible. Strength is also needed. Therefore, as described above, the width a1 of the first core portion a is widened, and the second core portion b
If the tensile stress acting on the
Since the mechanical holding force is effectively exerted in the iron core portion b, the second iron core portion b can be made smaller and magnetic saturation can be made easier.

Further, the second core portion b is formed by the first convex portion 12d-1.
Is located at the center of b5 from the base end of the second protrusion 12b-1 to the base end of the second protrusion 12b-1, so that the second core part b is at the optimum position, and the partial stress concentration in the second core part b is most relieved. Can be done.

Further, by setting the width b4 of the second iron core portion b in the circumferential direction of the rotor iron core so as to satisfy the relationship of the above equation (1), the demagnetizing force applied to the permanent magnet 14 does not become excessive and is not generated. The optimum value does not cause a decrease in torque.

Further, since the third core portion b has a substantially triangular shape in which the width in the circumferential direction of the rotor core gradually decreases from the outer peripheral side to the inner peripheral side of the rotor core, the third core portion b is hardly deformed, and the fluctuation torque due to disturbance. It has a mechanical strength capable of withstanding the above-mentioned conditions, and has a structure in which magnetic saturation is easy in a narrow portion (c1). In particular, by making the width c2 in the circumferential direction of the rotor core at the outer peripheral side of the third core portion c twice or more the width c1 in the circumferential direction of the rotor core at the inner peripheral side portion of the third core portion c,
The effect becomes remarkable.

[0048]

As described above in detail with the embodiments of the present invention, according to the rotor structure of the permanent magnet type synchronous rotating electric machine of the first invention, the first core part, the second core part, and the 3
The magnetic core of the rotor is configured by easily magnetically saturating the iron core and magnetically insulating the gap between the poles. That is, there is no need to separate the rotor core in the circumferential direction or provide a permanent magnet for magnetic insulation. In addition, the rotor core is an integral member connected at the first core portion, the second core portion, and the third core portion, and the first core portion, the second core portion, and the third core portion all rotate. Since it has a size capable of supporting the centrifugal force, it is not necessary to provide a nonmagnetic material for reinforcement. For this reason, the structure can be simplified and the cost can be reduced, and the speed can be increased and the size can be reduced (the torque per load can be increased).

Further, according to the rotor structure of the permanent magnet type synchronous rotating electric machine of the second invention, the width of the first iron core portion in the radial direction of the rotor iron core is adjusted to the other rotor slots and the outer peripheral surface of the rotor iron core. In the second iron core part b, the tensile stress acting on the second iron core part due to the rotational centrifugal force is averaged by making the width of the iron core part between the rotor core parts larger than the width in the radial direction of the rotor iron core. The mechanical holding force is effectively exerted, and the second iron core portion b can be made smaller and magnetic saturation can be made easier.

Further, according to the rotor structure of the permanent magnet type synchronous rotating electric machine of the third invention, the second core portion is located at the center between the base end of the first protrusion and the base end of the second protrusion. By doing so, the second core portion is at an optimal position, and partial stress concentration in the second core portion can be most relaxed.

Further, according to the rotor structure of the permanent magnet type synchronous rotating electric machine of the fourth invention, the width b4 of the second core portion in the circumferential direction of the rotor core is set to a size satisfying the following relationship. Therefore, the demagnetizing force applied to the permanent magnet does not become excessive, and the optimal value does not cause a decrease in generated torque.

B4 / (2 × thickness of permanent magnet) = coercive force of permanent magnet / iron plate saturation magnetic field

According to the rotor structure of the permanent magnet type synchronous rotating electric machine of the fifth or sixth aspect of the present invention, the width of the third core portion in the circumferential direction of the rotor core is changed from the outer peripheral side to the inner peripheral side of the rotor core. By adopting a substantially triangular shape that gradually decreases, the structure has a mechanical strength that is hardly deformed and can withstand fluctuation torque and the like due to disturbance, and is easily magnetically saturated in a narrow portion. In particular, the effect is remarkable by setting the width in the circumferential direction of the rotor core at the outer peripheral side portion of the third core portion to be at least twice the width in the circumferential direction of the rotor core at the inner peripheral side portion of the third core portion. Becomes

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a rotor structure of a permanent magnet type synchronous rotating electric machine according to an embodiment of the present invention.

FIG. 2 is a partially enlarged view of FIG.

FIG. 3 is an explanatory diagram of a tensile stress acting on an iron core of the rotor shown in FIG. 1;

FIG. 4A is a cross-sectional view showing a rotor structure of a conventional permanent magnet synchronous rotating electric machine, and FIG. 4B is a longitudinal cross-sectional view showing a lower half of the rotor structure without a lower half thereof.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Rotor 12 Rotor core 12a Electromagnetic iron plate 12b, 12c Rotor slot 12d Magnet slot 12b-1 2nd convex part 12d-2 1st convex part 13 Aluminum conductor (secondary conductor) 14 Permanent magnet 16 Shaft a 1st Iron core b Second iron core c Third iron core

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Seiji Sato 2-1-1-17 Osaki, Shinagawa-ku, Tokyo Inside Meidensha Co., Ltd.

Claims (6)

[Claims] 1. A rotor core, a secondary conductor provided in a rotor slot formed in the rotor core, and a permanent magnet provided in a magnet slot formed in the rotor core to constitute a magnetic pole of the rotor. And a rotating shaft fitted and fixed to the inner peripheral portion of the rotor core, the rotor structure of a permanent magnet type synchronous rotating electric machine, wherein the rotor slots are substantially equal along the rotor core circumferential direction. A first core portion which is formed at intervals and has a size which is easily magnetically saturated and can support the rotational centrifugal force is provided between the rotor slot located between the poles of the rotor and the outer peripheral surface of the rotor core. The magnet slots are formed at substantially equal intervals along the circumferential direction of the rotor core inside the rotor core radial direction relative to the rotor slots, and adjacent magnet slots are provided between the poles of the rotor. Are connected to each other to form a first convex portion on the outer peripheral side of the connecting portion. A second iron core large enough to be magnetically saturated and capable of supporting the rotational centrifugal force between the protrusion and the second protrusion formed on the inner peripheral side of the rotor slot located between the poles of the rotor. The magnetic poles are easily magnetically saturated between the magnet slots in each magnetic pole of the rotor, can support the centrifugal force of rotation, and can withstand the torque transmission to the rotating shaft. A rotor structure of a permanent magnet type synchronous rotating electric machine having three iron cores. 2. The rotor structure of a permanent magnet type synchronous rotating electric machine according to claim 1, wherein a width of the first core portion in a radial direction of the rotor core is set to be equal to other rotor slots and an outer peripheral surface of the rotor core. Wherein the width of the core in the radial direction is wider than the width of the rotor in the radial direction, so that the tensile stress acting on the second core due to the rotational centrifugal force is averaged. Rotor structure of rotating electric machine. 3. The rotor structure of a permanent magnet type synchronous rotating electric machine according to claim 1, wherein the second core portion is a center between a base end of the first protrusion and a base end of the second protrusion. The rotor structure of a permanent magnet type synchronous rotating electric machine characterized by being located in the following. 4. A rotor structure of a permanent magnet type synchronous rotating electric machine according to claim 1, wherein the width b4 of the second core portion in the circumferential direction of the rotor core is represented by the following formula: b4 / (2 × The thickness of the permanent magnet) = the coercive force of the permanent magnet / the saturation magnetic field of the iron plate. 5. The rotor structure of a permanent magnet type synchronous rotating electric machine according to claim 1, wherein the third core portion has a width in a circumferential direction of the rotor core from an outer peripheral side of the rotor core. A rotor structure of a permanent magnet type synchronous rotating electric machine having a substantially triangular shape that gradually decreases toward a peripheral side. 6. The rotor structure of a permanent magnet type synchronous rotating electric machine according to claim 5, wherein the width of the third core portion in the outer peripheral side portion in the circumferential direction of the rotor core is set to the inner peripheral side portion of the third core portion. The rotor structure of a permanent magnet type synchronous rotating electric machine, wherein the width of the rotor in the circumferential direction of the rotor core is twice or more.