JP2006262603A - Rotary electric machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotary electric machine in which torque ripples can be reduced, using a simple arrangement. <P>SOLUTION: The rotary electric machine 1 comprises a stator 2 arranged with a winding 6, and a rotor 3 where a main magnet 9 magnetized in the radial direction and an auxiliary magnet 10, magnetized in a direction other than the radial direction, are provided alternately in the circumferential direction on a rotor core 8 supported rotatably for the stator 2. The circumferential width Wr of the stator 2 side side face of the main magnet 9 is set narrower than the circumferential width Ws of the side face of the stator 2 side of the auxiliary magnet 10, arranged in the circumferential direction between the main magnets 9. One auxiliary magnet 10 is provided between respective main magnets 9. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a rotating electrical machine.

  Conventionally, as disclosed in Patent Document 1, a rotating electrical machine in which permanent magnets provided on a rotor are arranged in a Halbach array has been proposed. By making the permanent magnets in the Halbach arrangement, the magnetic force in a specific direction can be increased, and for example, a larger amount of magnet torque can be used compared to a normal arrangement magnet formed of the same amount of magnets. For this reason, high output can be achieved without increasing the size of the rotating electrical machine.

  Here, an example of a rotating electrical machine in which the permanent magnets are arranged in a Halbach array is shown in FIG. The rotating electrical machine 20 shown in FIG. 8 includes a stator 21 provided with windings and a rotor 23 having a permanent magnet 22, and the permanent magnet 22 is a main magnet 24 magnetized in the radial direction. And an auxiliary magnet 25 magnetized in a direction perpendicular to the magnetic pole direction of the main magnet 24. With this configuration, since the magnetic force on the air gap side of the permanent magnet 22 can be increased, for example, compared with a case where the permanent magnet does not include an auxiliary magnet, higher output can be achieved with the same magnet amount.

For example, Patent Document 2 proposes a rotating electrical machine in which a permanent magnet is divided into multiple parts. With this configuration, the surface magnetic flux density distribution in the air gap portion of the rotating electrical machine approaches a sine wave, so that the cogging torque can be reduced and the ripple can be reduced.
JP 11-308793 A JP 2002-354721 A

  However, with the configuration of Patent Document 2, it is necessary to assemble a large number of permanent magnets, so that it is necessary to form the magnets with high accuracy, and the number of steps for assembly increases. For this reason, there existed a problem that manufacture was complicated and time-consuming. Even if the surface magnetic flux density distribution of the rotor approaches a sine wave, there is still a problem that torque ripple occurs.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide a rotating electrical machine capable of reducing torque ripple with a simple configuration.

  In order to solve the above-mentioned problem, the invention according to claim 1 is characterized in that a main body magnetized in a radial direction on a stator provided with windings and a rotor core supported rotatably with respect to the stator. A rotating electrical machine including a magnet and auxiliary magnets magnetized in a direction other than the radial direction, wherein the main magnet is a circumferential direction of a side surface on the stator side. The width is set to be smaller than the circumferential width of the side surface on the stator side of the auxiliary magnet arranged between the main magnets in the circumferential direction.

According to a second aspect of the present invention, in the rotating electric machine according to the first aspect, one auxiliary magnet is provided between the main magnets.
According to a third aspect of the present invention, in the rotating electrical machine according to the first or second aspect, the auxiliary magnet is magnetized in a direction perpendicular to a center line extending in a radial direction of the auxiliary magnet.

  According to a fourth aspect of the present invention, in the rotating electrical machine according to any one of the first to third aspects, the main magnet has a circumferential width Wr on the side surface on the stator side that is a magnetic pole pitch width P. On the other hand, it has a magnet shape such that 0.2P <Wr <0.5P.

  According to a fifth aspect of the present invention, in the rotating electrical machine according to any one of the first to fourth aspects, the amount of magnetic flux of the main magnet gradually decreases from a center line extending in the radial direction to both ends in the circumferential direction. It is formed to become.

According to a sixth aspect of the present invention, in the rotating electrical machine according to any one of the first to fifth aspects, the stator is slotless.
According to a seventh aspect of the present invention, a main magnet magnetized in a radial direction and a rotor magnet other than the radial direction are attached to a stator provided with windings and a rotor core supported rotatably with respect to the stator. A rotating electric machine including a rotor with magnetized auxiliary magnets provided alternately in the circumferential direction, wherein the main magnet has an angle formed between the circumferential end surfaces of the main magnet in the circumferential direction. It is set to be smaller than the angle formed by the circumferential end surfaces of the auxiliary magnets disposed therebetween.

(Function)
According to the first aspect of the present invention, the main magnet has a circumferential width on the side surface on the stator side that is greater than a circumferential width on the side surface on the stator side of the auxiliary magnet disposed between the main magnets in the circumferential direction. Is set to be smaller. For this reason, the boundary portion between the main magnet and the auxiliary magnet, that is, the portion where the magnetic flux from the main magnet and the magnetic flux from the auxiliary magnet collide and the surface magnetic flux peaks, the circumferential width of the main magnet and the auxiliary magnet It approaches as compared with the case where the circumferential width is equal. As a result, since the surface magnetic flux density distribution approaches a sine wave, torque ripple can be reduced. Moreover, since the circumferential width of the side surface on the stator side of the main magnet is only made smaller than the circumferential width of the side surface on the stator side of the auxiliary magnet, the number of magnets is increased with respect to the number of magnetic poles, etc. There is no need. Therefore, torque ripple can be reduced with a simple configuration.

  According to the invention described in claim 2, since one auxiliary magnet is provided between each main magnet, for example, compared with a case where a plurality of auxiliary magnets are formed between the main magnets in the circumferential direction. Thus, the number of parts can be reduced, and high-precision machining is not required to form the auxiliary magnet.

  According to the third aspect of the present invention, the magnetizing direction of the auxiliary magnet is perpendicular to the center line extending in the radial direction of the auxiliary magnet, so the rotor rotates in either the forward or reverse direction. The rotational force does not change. For this reason, it can be set as the rotary electric machine with the same output performance in the forward / reverse direction.

  According to the fourth aspect of the present invention, the circumferential width Wr of the side surface on the stator side of the main magnet is 0.2P <Wr <0.5P with respect to the magnetic pole pitch width P, whereby the main magnet As compared with the case where the circumferential width of the auxiliary magnet is made larger than the circumferential width of the auxiliary magnet, the torque ripple can be reduced while maintaining the output torque.

  According to the fifth aspect of the present invention, since the main magnet is formed so that the amount of magnetic flux decreases as it approaches the boundary portion with the auxiliary magnet, the peak of the amount of magnetic flux generated in this portion is reduced, and the surface The magnetic flux density distribution is closer to a sine wave. For this reason, torque ripple can be further reduced.

According to the sixth aspect of the present invention, since the stator is slotless, the rotor rotates smoothly and torque ripple can be further reduced.
According to the seventh aspect of the present invention, the angle formed by the circumferential end surfaces of the main magnet is smaller than the angle formed by the circumferential end surfaces of the auxiliary magnets disposed between the main magnets in the circumferential direction. Is set to For this reason, the boundary between the main magnet and the auxiliary magnet, that is, the portion where the magnetic flux from the main magnet and the magnetic flux from the auxiliary magnet collide with each other and the surface magnetic flux reaches its peak is the angle of the main magnet and the angle of the auxiliary magnet. Compared to the case where and are equal. As a result, since the surface magnetic flux density distribution approaches a sine wave, torque ripple can be reduced. Further, since the angle formed by the circumferential end surfaces of the main magnet is merely made smaller than the angle formed by the circumferential end surfaces of the auxiliary magnet, there is no need to increase the number of magnets with respect to the number of magnetic poles. Therefore, torque ripple can be reduced with a simple configuration.

  According to the present invention, torque ripple can be reduced with a simple configuration.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the rotating electrical machine 1 according to the present embodiment includes a stator 2 and a rotor 3.

  The stator 2 includes a stator core 4 formed in a substantially cylindrical shape, a plurality (12 in this embodiment) of teeth 5 formed radially inside the stator core 4, and a winding wound around the teeth 5. Line 6. The winding 6 is connected to a power supply device (not shown), and is configured to generate a rotating magnetic field that rotates the rotor 3 when supplied with power.

  The rotor 3 is rotatably supported inside the stator 2. The rotor 3 is formed by alternately providing main magnets 9 and auxiliary magnets 10 in the circumferential direction on a rotor core 8 provided to be rotatable with respect to the stator 2 around a rotation shaft 7. The boundary between each main magnet 9 and auxiliary magnet 10 is formed to be in the radial direction. The main magnet 9 is magnetized in the radial direction, and the auxiliary magnet 10 is magnetized in a direction perpendicular to the center line Ls extending in the radial direction of the auxiliary magnet 10 on a plane orthogonal to the rotating shaft 7. . The main magnet 9 is uniformly magnetized in the circumferential direction, and the auxiliary magnet 10 is uniformly magnetized in the radial direction. In the present embodiment, the rotor 3 is an 8-pole surface magnet type rotor, and one auxiliary magnet 10 is provided between each main magnet 9. Further, the circumferential width Wr of the side surface on the stator 2 side (outer peripheral side) of the main magnet 9 is set to be smaller than the circumferential width Ws of the side surface on the stator side (outer peripheral side) of the auxiliary magnet 10. Yes. Specifically, when the circumferential width between the center lines Ls extending in the radial direction of the auxiliary magnet 10 formed on both sides in the circumferential direction of the main magnet 9 is a magnetic pole pitch width P, the main magnet 9 has a circumferential width Wr. The pitch width P is formed so that 0.2P <Wr <0.5P. The plurality of main magnets 9 and auxiliary magnets 10 arranged in the circumferential direction are integrally formed, and are formed by magnetizing a substantially cylindrical magnetic body.

As an example, the rotating electrical machine 1 having the above configuration was measured.
First, the surface magnetic flux density distribution of the rotating electrical machine 1 was measured. For comparison, the surface magnetic flux density distribution was measured using a conventional rotating electrical machine 20 shown in FIG. 8 and a rotating electrical machine 30 as a comparative example shown in FIG. 9 as an 8-pole surface magnet type rotating electrical machine. In addition, about the rotary electric machines 20 and 30, the volume of the permanent magnets 22 and 32 was made the same as the volume which combined the main magnet 9 and the auxiliary magnet 10 of the Example, and it measured by making magnetic pole pitch width the same. The rotating electrical machine 20 is configured in the same manner as the rotating electrical machine 1 of the present embodiment in that the circumferential width of the side surface of the main magnet 24 on the stator 21 side is substantially the same as the circumferential width of the side surface of the auxiliary magnet 25 on the stator 21 side. Is different. Further, the rotating electrical machine 30 of the comparative example is different from the rotating electrical machine 1 of the present embodiment in that the permanent magnet 32 of the rotor 31 is composed only of the main magnet 33 and does not include an auxiliary magnet. That is, the permanent magnet 32 of the rotating electrical machine 30 is formed only of magnets magnetized in the radial direction.

  The result is shown in FIG. Here, 90 ° corresponding to one pole pair is displayed as an electrical angle of 360 °. As shown in FIG. 2, in the rotating electrical machine 30, the magnetic flux density distribution is a rectangular wave distribution. Further, in the rotating electrical machine 20, the magnetic flux density distribution approaches a sine wave shape, and in the rotating electrical machine 1, the magnetic flux density distribution approaches a sine wave shape.

  Moreover, the result of having performed waveform analysis from magnetic flux density distribution shown in FIG. 2 is shown in FIG. FIG. 3 shows the intensity of the harmonic component included in the surface magnetic flux density distribution, and shows the harmonic component of the example and the conventional example in a ratio with respect to the harmonic component in the rotating electrical machine 30 of the comparative example. ing.

  As shown in FIG. 3, the example of the primary basic component was the largest in comparison with the comparative example and the conventional example. From this result, it is considered that the rotating electrical machine 1 of the present embodiment can generate a larger rotational torque than the rotating electrical machine 20 of the conventional example. In the embodiment, compared with the conventional example, the harmonic component is moved to the higher order side. From this result, it is considered that the cogging torque can be reduced in the rotating electrical machine 1 of the present embodiment.

  FIG. 4 shows changes in torque ripple and output torque with respect to the circumferential width Ws of the side surface of the auxiliary magnet 10 on the stator 2 side. As shown in FIG. 4, the torque ripple gradually increases as the circumferential width Ws becomes larger than 0.5P (that is, the circumferential width of the side surface on the stator 21 side of the auxiliary magnet 25 in the conventional rotating electrical machine 20). Reduced to When the circumferential width Ws becomes larger than 0.8P, the torque ripple tends to increase.

  As a result, when the circumferential width Ws of the auxiliary magnet 10 is in the range of 0.5P <Ws <0.8P, that is, the circumferential width Wr of the main magnet 9 is in the range of 0.2P <Wr <0.5P. It was confirmed that the occurrence of torque ripple can be suppressed as compared with the conventional rotating electrical machine 20. As shown in FIG. 4, when the circumferential width Ws of the auxiliary magnet 10 is in the range of 0.5P <Ws <0.8P, the output torque tends to decrease, but is almost maintained.

Next, characteristic effects of the above embodiment will be described below.
(1) In the main magnet 9, the circumferential width Wr of the side surface on the stator 2 side is larger than the circumferential width Ws of the side surface on the stator 2 side of the auxiliary magnet 10 disposed between the main magnets 9 in the circumferential direction. It is set to be smaller. For this reason, the boundary portion between the main magnet 9 and the auxiliary magnet 10, that is, the portion where the magnetic flux from the main magnet 9 and the magnetic flux from the auxiliary magnet 10 collide with each other and the surface magnetic flux reaches its peak is the circumferential width of the main magnet. Compared with the case where the circumferential width of the auxiliary magnet is equal. As a result, since the surface magnetic flux density distribution approaches a sine wave, torque ripple can be reduced. In addition, since the circumferential width Wr of the side surface of the main magnet 9 on the stator 2 side is only made smaller than the circumferential width Ws of the side surface of the auxiliary magnet 10 on the stator 2 side, the number of magnetic poles There is no need to increase the number. Therefore, torque ripple can be reduced with a simple configuration.

  (2) Since one auxiliary magnet 10 is provided between each main magnet 9, for example, the number of parts is reduced compared to a case where a plurality of auxiliary magnets are formed between the main magnets in the circumferential direction. In addition, high-precision processing is not required to form the auxiliary magnet 10.

  (3) Since the magnetizing direction of the auxiliary magnet 10 is perpendicular to the center line Ls extending in the radial direction of the auxiliary magnet 10, the rotational force is generated even if the rotor 3 rotates in either forward or reverse direction. does not change. For this reason, it can be set as the rotary electric machine with the same output performance in the forward / reverse direction. The magnetization direction of the auxiliary magnet 10 is a direction on a plane orthogonal to the rotation axis 7.

  (4) Since the circumferential width Wr of the main magnet 9 is 0.2P <Wr <0.5P with respect to the magnetic pole pitch width P, the circumferential width of the main magnet is made larger than the circumferential width of the auxiliary magnet. Compared with the case of increasing the torque ripple, the torque ripple can be reduced while maintaining the output torque.

The above embodiment may be modified as follows.
In the above embodiment, the main magnet 9 is uniformly magnetized in the circumferential direction, but may be magnetized so that the amount of magnetic flux changes in the circumferential direction. For example, as shown in FIG. 5B, the amount of magnetic flux gradually increases from the radial center line Lr to both ends of each main magnet 9 constituting the rotating electrical machine 1 of the above embodiment shown in FIG. You may form so that it may become small. With this configuration, the main magnet 9 is formed so that the amount of magnetic flux decreases as it approaches the boundary portion with the auxiliary magnet 10, so that the peak of the amount of magnetic flux generated in this portion is reduced, and FIG. As indicated by the bold line, the surface magnetic flux density distribution approaches a sine wave shape. For this reason, torque ripple can be further reduced.

  In the above embodiment, the plurality of main magnets 9 and auxiliary magnets 10 are integrally formed in a substantially cylindrical shape, but each main magnet and auxiliary magnet are divided on a surface along the radial direction. It is also good.

  In the above embodiment, the plurality of main magnets 9 and auxiliary magnets 10 are integrally formed in a substantially cylindrical shape, but are divided into a plurality of parts on a plane perpendicular to the axial direction, and each of them is appropriately formed. The skew angle may be shifted. With this configuration, the cogging torque can be reduced.

A metal cover formed of stainless steel or the like may be placed on the outer peripheral side of the main magnet 9 and the auxiliary magnet 10.
-Iron formed of a magnetic material may be sandwiched between a plurality of main magnets 9, auxiliary magnets 10, and rotor cores 8 arranged in the circumferential direction.

  In the above embodiment, the stator 2 has a structure in which slots are formed by forming the teeth 5, but as shown in FIG. 7, the stator 2 may be a rotary electric machine 15 in which the stator 2 is slotless. . If comprised in this way, the rotor 3 will rotate smoothly and it can aim at reduction of a torque ripple more.

In the above embodiment, the winding 6 is a concentrated winding type, but may be a distributed winding type.
In the above embodiment, the inner rotor type rotating electric machine has been described. However, the present invention may be applied to an outrotor type rotating electric machine. In that case, what is necessary is just to set so that the circumferential width of the inner peripheral side surface (side surface on the stator side) of the main magnet is smaller than the circumferential width of the inner peripheral side surface of the auxiliary magnet.

  In the above embodiment, the circumferential width Wr of the side surface of the main magnet 9 on the stator 2 side is set to be smaller than the circumferential width Ws of the side surface of the auxiliary magnet 10 on the stator 2 side. You may set so that the angle which the circumferential direction both end surfaces make may become smaller than the angle which the circumferential direction both end surfaces of an auxiliary magnet make.

The schematic block diagram of the rotary electric machine in this Embodiment. The electrical angle-surface magnetic flux density distribution characteristic figure of a rotary electric machine. Explanatory drawing which shows distribution of the harmonic component of the surface magnetic flux density distribution of a rotary electric machine. The circumferential direction width-torque ripple and output torque characteristic view of the side surface on the stator side of the auxiliary magnet. (A), (b) is explanatory drawing of the rotary electric machine of a modification. The electrical angle-surface magnetic flux density distribution characteristic figure of the rotary electric machine of a modification. The schematic block diagram of the rotary electric machine of a modification. The schematic block diagram of the rotary electric machine of a prior art example. The schematic block diagram of the rotary electric machine of a comparative example.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1,15 ... Rotary electric machine, 2 ... Stator, 3 ... Rotor, 6 ... Winding, 8 ... Rotor core, 9 ... Main magnet, 10 ... Auxiliary magnet, Wr ... Circumferential width of side surface of main magnet on the stator side , Ws: circumferential width of the side surface on the stator side of the auxiliary magnet, Lr: center line extending in the radial direction of the main magnet, Ls: center line extending in the radial direction of the auxiliary magnet, P: magnetic pole pitch width.

Claims (7)

A stator provided with windings;
A rotor in which a main magnet magnetized in a radial direction and an auxiliary magnet magnetized in a direction other than the radial direction are alternately provided in a circumferential direction on a rotor core supported rotatably with respect to the stator;
A rotating electric machine with
The main magnet is set so that the circumferential width of the side surface on the stator side is smaller than the circumferential width of the side surface on the stator side of the auxiliary magnet disposed between the main magnets in the circumferential direction. Rotating electric machine characterized by that. In the rotating electrical machine according to claim 1,
One auxiliary magnet is provided between the main magnets, respectively. In the rotating electrical machine according to claim 1 or 2,
The rotary electric machine is characterized in that the auxiliary magnet is magnetized in a direction perpendicular to a center line extending in a radial direction of the auxiliary magnet. The rotating electrical machine according to any one of claims 1 to 3,
Each of the main magnets has a circumferential width Wr of the side surface on the stator side with respect to the magnetic pole pitch width P.
0.2P <Wr <0.5P
A rotating electric machine characterized by having a magnet shape. The rotating electrical machine according to any one of claims 1 to 4,
The rotating machine is characterized in that the main magnet is formed such that the amount of magnetic flux gradually decreases from a center line extending in the radial direction to both ends in the circumferential direction. The rotating electrical machine according to any one of claims 1 to 5,
The rotating electric machine according to claim 1, wherein the stator is slotless. A stator provided with windings;
A rotor in which a main magnet magnetized in a radial direction and an auxiliary magnet magnetized in a direction other than the radial direction are alternately provided in a circumferential direction on a rotor core supported rotatably with respect to the stator;
A rotating electric machine with
The main magnet is set such that an angle formed by both circumferential end surfaces is smaller than an angle formed by the circumferential end surfaces of the auxiliary magnet disposed between the main magnets in the circumferential direction. Rotating electric machine.

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