JP2023035442A - Embedded magnet-type rotor and rotary electric machine - Google Patents

Abstract

To provide an embedded magnet-type rotor applying three magnets to one magnetic pole for improving the maximum torque of a rotary electric machine and reducing manufacturing costs.SOLUTION: In an embedded magnet-type rotor in which a plurality of magnetic poles are formed in a circumferential direction of an iron core, each magnetic pole includes a first magnet arranged at the magnetic pole center, a second magnetic arranged on the reversed side of the rotor so as to be inclined with respect to the magnetic pole center, and a third magnetic arranged on the forward side of the rotor so as to be inclined with respect to the magnetic pole center. The first magnet, the second magnet, and the third magnet have the same shape, the second magnet and the third magnet are arranged asymmetrically with respect to the magnetic pole center, and an angle θ1 formed between the magnetic pole center and the magnetic pole surface of the first magnetic, an angle θ2 formed between the magnetic pole center and the magnetic pole surface of the second magnetic, and an angle θ3 formed between the magnetic pole center and the magnetic pole surface of the third magnetic fulfill the relation of θ3>θ2>1/2(θ1).SELECTED DRAWING: Figure 2

Description

The present invention relates to an embedded magnet rotor and a rotating electric machine.

Conventionally, in order to improve the maximum torque of a rotating electric machine, a configuration is known in which two magnets are arranged in one magnetic pole of an embedded magnet rotor and the magnets are arranged asymmetrically with respect to the magnetic pole center ( For example, see Patent Documents 1 and 2). In addition, Patent Document 2 proposes applying two magnets having the same shape and the same size to one magnetic pole in order to reduce the manufacturing cost of a rotating electric machine.

JP 2019-201479 A JP 2019-50689 A

However, the above patent documents do not take into consideration the arrangement of the magnets when three magnets are applied to one magnetic pole. Moreover, even when three magnets are applied to one magnetic pole, it is preferable to reduce the manufacturing cost.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides an embedded magnet rotor in which three magnets are applied to one magnetic pole to improve the maximum torque of a rotating electric machine and to reduce manufacturing costs. intended to

One aspect of the present invention is an embedded magnet rotor in which a plurality of magnetic poles are formed in the circumferential direction of an iron core. Each magnetic pole consists of a first magnet arranged at the center of the magnetic pole, a second magnet arranged at an angle to the center of the magnetic pole on the reverse rotation side of the rotor, and an angle at the forward rotation side of the rotor inclined with respect to the center of the magnetic pole. and a third magnet positioned in the . The first magnet, the second magnet and the third magnet have the same shape, the second magnet and the third magnet are arranged asymmetrically with respect to the magnetic pole center, and the angle between the magnetic pole center and the magnetic pole face of the first magnet is θ1 , the angle θ2 formed between the magnetic pole center and the magnetic pole surface of the second magnet, and the angle θ3 formed between the magnetic pole center and the magnetic pole surface of the third magnet satisfy the relationship θ3>θ2>1/2 (θ1).

In the embedded magnet rotor described above, the second magnets and the third magnets may be arranged in a pattern in which the distance between the second magnets and the third magnets increases toward the outer circumference of the iron core, with the magnetic pole center separated.
In the embedded magnet rotor described above, the magnetic pole faces of the first magnets may be inclined with respect to a line orthogonal to the magnetic pole center.
In the embedded magnet rotor described above, the iron core may further have a magnetic shielding portion on the inner peripheral side of the first magnet and between the second magnet and the third magnet.
In the embedded magnet rotor described above, the angle θ1 may be 93°, the angle θ2 may be 48°, and the angle θ3 may be 52°.
A rotating electric machine according to another aspect of the present invention includes a stator and the embedded magnet rotor described above.

ADVANTAGE OF THE INVENTION According to one aspect of the present invention, in an embedded magnet rotor in which three magnets are applied to one magnetic pole, it is possible to improve the maximum torque of a rotating electrical machine and to reduce manufacturing costs.

1 is a cross-sectional view of a rotary electric machine according to a first embodiment; FIG. It is a figure which shows the structural example of the rotor for 1 magnetic pole in 1st Embodiment. 5 is a diagram showing a configuration example of a rotor for one magnetic pole in Comparative Example 1; FIG. 4 is a graph showing torque change rates of the first embodiment and Comparative Example 1. FIG. It is a figure which shows the structural example of the rotor for 1 magnetic pole in 2nd Embodiment. FIG. 10 is a diagram showing a configuration example of a rotor for one magnetic pole in Comparative Example 2; 9 is a graph showing torque change rates of the second embodiment and comparative example 2. FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In order to facilitate the understanding of the description in the embodiments, structures and elements other than the main part of the present invention will be described with simplification or omission. Moreover, in the drawings, the same reference numerals are given to the same elements. It should be noted that the shape, dimensions, etc. of each element shown in the drawings are schematically shown, and do not represent the actual shape, dimensions, etc.

<First Embodiment>
FIG. 1 is a cross-sectional view showing a cross-section in a direction orthogonal to the rotation axis Ax in the rotating electrical machine of the first embodiment.

A rotary electric machine 1 shown in FIG. 1 is an inner rotor type motor, and has a rotor 2 which is an example of an embedded magnet type rotor, and a cylindrical stator 3 arranged on the outer circumference of the rotor 2 . In FIG. 1, the extension direction of the rotation axis Ax of the rotary electric machine 1 is the direction perpendicular to the paper surface. Further, the rotation electric machine 1 assumes that the counterclockwise direction is the forward rotation direction.

A stator 3 is arranged on the outer circumference of the rotor 2 with an air gap therebetween. In the rotating electric machine 1 , the magnetic field of the stator 3 is switched in order by current control of the coil, so that the rotor 2 rotates about the rotation axis Ax due to the attractive force or repulsive force with the magnetic field of the rotor 2 .

The stator 3 accommodates the rotor 2 in a central space portion centered on the rotation axis Ax. On the inner peripheral side of the stator 3, a plurality of teeth 3a protruding inward in the radial direction toward the rotation axis Ax are arranged at equal intervals in the circumferential direction. Spaces between adjacent teeth 3a form slots 3b, respectively. A stator coil (not shown) is mounted along the outer circumference of the rotor 2 in the slot 3b.

The rotor 2 has an iron core 4 , a shaft 5 and permanent magnets 6 .
The iron core 4 of the rotor 2 is, for example, a cylindrical member formed by stacking stamped silicon steel plates in the axial direction. An insulating adhesive is interposed between the individual silicon steel plates forming iron core 4, and the individual silicon steel plates are insulated from each other. A shaft 5 is fitted in the axial center portion of the iron core 4 along the rotation axis Ax. In the rotary electric machine 1, the shaft 5 is rotatably supported by bearings (not shown).

The rotor 2 of the first embodiment is an eight-pole rotor, and a plurality of permanent magnets 6 are arranged in a predetermined arrangement in the iron core 4 of the rotor 2 so that eight magnetic poles are formed at equal intervals along the circumferential direction. be done. The permanent magnets 6 are arranged such that magnetic poles adjacent to each other in the rotor 2 have opposite polarities.

FIG. 2 is a diagram showing a configuration example of the rotor 2 for one magnetic pole in the first embodiment.
In one magnetic pole of the iron core 4, the axis connecting the axial center (rotating axis Ax) of the rotor 2 in FIG. 1 and the magnetic pole center that generates magnet torque is the d-axis of the dq axis coordinates. Also, the axis orthogonal to the d-axis at an electrical angle is the q-axis of the dq-axis coordinates.

A first magnet hole 11 and an air gap 14 are formed on the d-axis of the iron core 4 . A second magnet hole 12 and a third magnet hole 13 are formed in the iron core 4 . The second magnet hole 12 and the third magnet hole 13 face each other across the d-axis and the air gap 14, and are formed in the iron core 4 in a pattern in which the distance between them increases as the outer circumference of the iron core 4 is approached.

The first magnet hole 11, the second magnet hole 12, the third magnet hole 13, and the air gap 14 are formed through the iron core 4 in parallel with the extension direction of the rotation axis Ax. Permanent magnets 6 having the same shape are fitted in the first magnet hole 11, the second magnet hole 12 and the third magnet hole 13, respectively.

Each permanent magnet 6 is formed in the shape of a rectangular block whose longitudinal dimension (direction parallel to the extension direction of the rotation axis Ax) is substantially the same as the longitudinal dimension of the iron core 4 . Also, the permanent magnet 6 is magnetized in a direction perpendicular to the long side on a plane perpendicular to the rotation axis Ax. Each permanent magnet 6 having the same magnetic pole has the same magnetic pole (S pole or N pole) on the magnetic pole surface facing the outer peripheral side.

The first magnet hole 11 is formed near the outer periphery of the iron core 4 and has a long side extending in a direction intersecting the d-axis on a plane perpendicular to the rotation axis Ax. The first magnet hole 11 has a magnet placement portion 11a into which the permanent magnet 6 is fitted, and flux barrier portions 11b formed on both sides of the magnet placement portion 11a. The permanent magnet 6 inserted into the magnet placement portion 11a is an example of a first magnet. The flux barrier formed in the magnetic pole has the function of smoothing the flow of magnetic flux to improve torque and reduce magnet loss.

In this embodiment, the long side of the magnet placement portion 11a in the first magnet hole 11 is inclined with respect to a line perpendicular to the d-axis. In other words, the angle θ1 formed by the long side of the magnet placement portion 11a (the magnetic pole surface of the first magnet) with respect to the d-axis is deviated from 90°. For example, the angle θ1 is 93° in mechanical angle.

The second magnet hole 12 is located on the right side in FIG. 2 and has a long side obliquely extending with respect to the d-axis on a plane perpendicular to the rotation axis Ax. The second magnet hole 12 has a magnet placement portion 12a into which the permanent magnet 6 is fitted, and flux barrier portions 12b formed on both sides of the magnet placement portion 12a. The permanent magnet 6 inserted into the magnet placement portion 12a is an example of a second magnet. In the second magnet hole 12, the angle θ2 formed by the long side of the magnet placement portion 12a (the magnetic pole surface of the second magnet) with respect to the d-axis is, for example, 48° in mechanical angle.

The third magnet hole 13 is located on the left side in FIG. 2 and has a long side obliquely extending with respect to the d-axis on a plane orthogonal to the rotation axis Ax. The third magnet hole 13 has a magnet placement portion 13a into which the permanent magnet 6 is fitted, and flux barrier portions 13b formed on both sides of the magnet placement portion 13a. The permanent magnet 6 inserted into the magnet arrangement portion 13a is an example of a third magnet. In the third magnet hole 13, the angle θ3 formed by the long side of the magnet placement portion 13a (the magnetic pole surface of the third magnet) with respect to the d-axis is, for example, 52° in mechanical angle.

As described above, the angle θ2 at the second magnet hole 12 and the angle θ3 at the third magnet hole 13 are different, and the permanent magnets 6 in the second magnet hole 12 and the permanent magnets 6 in the third magnet hole 13 are positioned on the d-axis. are arranged asymmetrically with respect to

In the first embodiment, compared to the permanent magnets 6 in the third magnet hole 13 located on the forward rotation side of the rotary electric machine 1, the permanent magnets 6 in the second magnet hole 12 located on the reverse side have a long side with respect to the d-axis. The angle θ (that is, the inclination with respect to the d-axis) is small (θ3>θ2). More specifically, three permanent magnets 6 are arranged in one magnetic pole under the condition that the angles θ1, θ2, and θ3 satisfy the relationship θ3>θ2>1/2 (θ1).

Further, the air gap 14 is formed on the inner peripheral side of the iron core 4 relative to the first magnet hole 11 and is sandwiched between the second magnet hole 12 and the third magnet hole 13 . The air gap 14 has a rectangular cross-sectional shape on a plane orthogonal to the rotation axis Ax, and its short sides are the flux barrier portion 12 b on the inner peripheral side of the second magnet hole 12 and the inner circumference of the third magnet hole 13 . They face the flux barrier portion 13b on the circumferential side, respectively. The air gap 14 has a function of suppressing magnetic flux leaking from the permanent magnet 6 inserted into the first magnet hole 11 to the inside of the rotor 2 .

Both the air gap 14 and the above flux barrier portions are holes (spaces), and have extremely low magnetic permeability compared to the iron core 4, making it difficult for magnetic flux to pass through them, so they function as magnetic shielding portions. It should be noted that even if the space 14 and the flux barrier portion are filled with a non-magnetic and low magnetic permeability metal (for example, aluminum, brass, etc.), an adhesive, a varnish, a resin, etc., they function as magnetic shielding portions. do.

The operation of the first embodiment will be described below.
The magnetic poles of the rotor 2 of the first embodiment are the first magnet of the first magnet hole 11 arranged on the d-axis and the second magnet of the second magnet hole 12 inclined to the d-axis and arranged on the reverse side. and a third magnet in a third magnet hole 13 arranged on the forward rotation side while being inclined with respect to the d-axis. The second magnet and the third magnet are arranged asymmetrically with respect to the d-axis. The angle θ3 formed by the magnetic pole faces of the third magnet satisfies the relationship θ3>θ2>1/2 (θ1).

In the rotor 2 of the first embodiment, the second magnet and the third magnet are arranged asymmetrically with respect to the d-axis so that the inclination of the magnetic pole surface of the second magnet with respect to the d-axis is smaller than that of the third magnet. . As a result, the current phase at which the magnet torque is maximized during forward rotation of the rotary electric machine 1 shifts toward the current phase at which the reluctance torque is maximized. Therefore, according to the first embodiment, the maximum torque during forward rotation of the rotary electric machine 1 can be improved. For example, when the rotary electric machine 1 of the first embodiment is installed in an electric vehicle, the performance of the electric vehicle can be improved by improving the maximum torque on the forward side of the electric vehicle.

Further, in the rotor 2 of the first embodiment, the three permanent magnets 6 (first magnet, second magnet, and third magnet) used for one magnetic pole all have the same shape. Therefore, in the first embodiment, since it is not necessary to prepare a plurality of types of permanent magnets 6, it is possible to suppress the manufacturing cost by reducing the mold cost of the permanent magnets 6. FIG. Further, in the first embodiment, compared to the case of using a plurality of types of permanent magnets 6, it is possible to suppress an increase in centrifugal force due to variations in magnet size and weight.

Next, the torque change rate based on the configuration of the first embodiment will be described.
FIG. 3 is a diagram showing a configuration example of the rotor 2 of Comparative Example 1 with respect to the first embodiment. The rotor 2 of Comparative Example 1 has a line-symmetrical pattern about the d-axis, and the permanent magnets 6 are arranged line-symmetrically about the d-axis in the iron core 4a. It differs from the composition of the form. That is, in the case of Comparative Example 1 in FIG. 3, the angle θ1′ is 90° in mechanical angle. Also, the angles θ2′ and θ3′ are equal to each other (θ2′=θ3′).

FIG. 4 is a graph showing torque change rates of the first embodiment and the first comparative example. The horizontal axis of FIG. 4 indicates the current phase [degree]. The vertical axis on the left side of FIG. 4 indicates torque [%], and the vertical axis on the right side of FIG.
As shown in FIG. 4, the torque in the configuration of the first embodiment has a larger maximum torque (when the current phase is 30 degrees in FIG. 4) than in Comparative Example 1, and the rate of change from Comparative Example 1 is the maximum torque side is about 1.02.

<Second embodiment>
FIG. 5 is a diagram showing a configuration example of the rotor 2 for one magnetic pole in the second embodiment. In addition, in the following description, the same reference numerals are given to the same configurations as in the first embodiment, and overlapping descriptions will be omitted.

The rotor 2 of the second embodiment is a modification of the first embodiment. This is an example in which a magnetic shielding portion is formed on the inner peripheral side of the first magnet hole 11 by .

Specifically, in the rotor 2 of the second embodiment, the flux barrier portion 12b1 on the inner peripheral side of the second magnet hole 12 and the flux barrier portion 13b1 on the inner peripheral side of the third magnet hole 13 are directed toward the d-axis. It extends inward. The flux barrier portion 12b1 and the flux barrier portion 13b1 form a pattern in which the tips are opposed to each other across the d-axis. Note that the permanent magnets 6 in the second embodiment are arranged asymmetrically with respect to the d-axis as in the first embodiment, and the values of the angles θ1, θ2, and θ3 are the same as in the first embodiment.

Next, the torque change rate based on the configuration of the second embodiment will be described.
FIG. 6 is a diagram showing a configuration example of the rotor 2 of Comparative Example 2 with respect to the second embodiment. The rotor 2 of Comparative Example 2 has a line-symmetrical pattern about the d-axis, and the permanent magnets 6 are arranged line-symmetrically about the d-axis. It differs from the composition of the form. That is, in the case of Comparative Example 2 in FIG. 6, the angle θ1′ is 90° in mechanical angle. Also, the angles θ2′ and θ3′ are equal to each other (θ2′=θ3′).

FIG. 7 is a graph showing torque change rates of the second embodiment and the second comparative example. The vertical and horizontal axes of FIG. 7 are the same as those of the graph of FIG.
As shown in FIG. 7, the torque in the configuration of the second embodiment has a larger maximum torque (when the current phase is 30 degrees in FIG. 7) than in Comparative Example 2, and the rate of change from Comparative Example 2 is the maximum torque side is about 1.01. As described above, the same effect as in the first embodiment can be obtained in the second embodiment as well.

The present invention is not limited to the above embodiments, and various improvements and design changes may be made without departing from the scope of the present invention.

For example, the values of the angles θ1, θ2, and θ3 in the present invention are not limited to the values in the above embodiment as long as they satisfy the relationship θ3>θ2>1/2 (θ1). For example, the angle θ1 may be 90° in mechanical angle, and the long sides of the permanent magnets 6 in the first magnet holes 11 may be perpendicular to the d-axis.

In the above embodiment, a configuration example with an 8-pole rotor has been described, but the number of poles of the rotor 2 is not limited to the above embodiment. Further, in the above embodiment, an example in which the counterclockwise direction of the rotating electrical machine 1 is the forward rotation direction has been described, but the clockwise direction of the rotating electrical machine 1 may be the forward rotation direction. When the clockwise direction is the normal rotation direction, the magnetic pole pattern of the rotor 2 has a shape that is left-right reversed from the above-described embodiment.

Further, in the above-described embodiment, a configuration example of a motor has been described, but the embedded magnet rotor of the present invention may be applied as a rotor of a generator. Further, when the embedded magnet rotor of the present invention is applied to a motor, the application of the motor is not limited to electric vehicles.

In addition, the embodiments disclosed this time should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the scope of the claims rather than the above description, and is intended to include all modifications within the scope and meaning of equivalents to the scope of the claims.

DESCRIPTION OF SYMBOLS 1... Rotary electric machine 2... Rotor 3... Stator 4... Iron core 5... Shaft 6... Permanent magnet 11... First magnet hole 12... Second magnet hole 13... Third magnet hole 14... Gap Part, 12b1, 13b1 ... flux barrier part

Claims (6)

An embedded magnet rotor in which a plurality of magnetic poles are formed in the circumferential direction of an iron core,
each of said magnetic poles comprising:
A first magnet arranged at the magnetic pole center, a second magnet inclined with respect to the magnetic pole center and arranged on the rotor reversal side, and an inclined with respect to the magnetic pole center and arranged on the rotor forward rotation side. a third magnet that
The first magnet, the second magnet and the third magnet have the same shape,
The second magnet and the third magnet are arranged asymmetrically with respect to the magnetic pole center,
The angle θ1 formed between the magnetic pole center and the magnetic pole surface of the first magnet, the angle θ2 formed between the magnetic pole center and the magnetic pole surface of the second magnet, and the angle θ3 formed between the magnetic pole center and the magnetic pole surface of the third magnet are θ3 > θ2 > 1/2 (θ1) is satisfied. The second magnet and the third magnet are arranged in a pattern in which the distance between them widens toward the outer circumference of the iron core with the center of the magnetic pole therebetween. 3. The embedded magnet rotor according to claim 1, wherein the magnetic pole faces of the first magnets are inclined with respect to a line orthogonal to the magnetic pole center. 4. The implant according to any one of claims 1 to 3, wherein the iron core further has a magnetic shielding portion on the inner peripheral side of the first magnet and between the second magnet and the third magnet. Magnetic rotor. 5. The embedded magnet rotor according to claim 1, wherein the angle .theta.1 is 93.degree., the angle .theta.2 is 48.degree., and the angle .theta.3 is 52.degree. a stator;
A rotary electric machine comprising the embedded magnet rotor according to any one of claims 1 to 5.

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