JPH11308793A - Outer rotor type permanent magnet motor - Google Patents

Abstract

(57) [Summary] In an outer rotor motor, by increasing the amount of magnetic flux generated by a permanent magnet, magnet torque can be more effectively used to maximize the torque generated by the same current. Provide an output motor. SOLUTION: By disposing auxiliary magnets 2b at both ends of a main magnet 2a in a direction perpendicular to the magnetic pole direction of the main magnet 2a, the amount of magnetic flux generated by the permanent magnet is increased.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an outer rotor type comprising a stator having windings mounted on an iron core having a plurality of slots, and a permanent magnet rotor rotatably arranged opposite to a magnetic pole surface of the stator. It relates to a permanent magnet motor.

[0002]

2. Description of the Related Art As shown in FIG. 8, a conventional outer rotor type permanent magnet motor has a stator 11 made of a magnetic material having a plurality of coils wound thereon and a rotor rotatably disposed outside the stator 11. 12 are provided. Usually, the rotor 12 has a structure in which permanent magnets 13 corresponding to respective poles are attached to the inner peripheral surface of a cylindrical magnetic body. The winding group applied to the stator 11 generates a rotating magnetic field, and magnetic flux enters the rotor 12 from the stator teeth.

[0003] When a current flows through the stator coil, a rotating magnetic field is generated in the stator 11, and a linkage between the rotating magnetic field and the magnetic field generated by the permanent magnet of the rotor generates a driving torque in the rotor, so that the rotor rotates synchronously.

[0004]

However, in the above-described conventional configuration, the magnetic flux leaked from the permanent magnet to the outer peripheral side of the rotor core is large, and the loss due to the leaked magnetic flux has been a problem.

The present invention solves such a conventional problem. A permanent magnet attached to a rotor core has a Hal
By applying the bach magnet array, the amount of magnetic flux generated by the permanent magnets is increased using the same amount of permanent magnets as before. Further, more magnetic flux of the permanent magnet is generated on the inner circumferential side of the rotor (air gap side) than on the outer circumferential side of the rotor.
It is another object of the present invention to provide a high-efficiency, high-output outer rotor motor by concentrating magnetic flux at the pole center and maximally utilizing magnet torque generated by the same current.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a stator in which a winding is mounted on an iron core having a plurality of slots, and a rotatably disposed facing a magnetic pole surface of the stator. In the outer rotor type permanent magnet motor provided with a permanent magnet rotor, the permanent magnets forming the respective poles include a central main magnet and auxiliary magnets having magnetic poles at both ends in a direction perpendicular to the magnetic pole direction of the main magnet. An outer rotor type permanent magnet motor characterized by being arranged, a permanent magnet having polarity in a direction perpendicular to the polarity of the main magnet is arranged at both ends of the permanent magnet, and a permanent magnet is generated. It is characterized in that the amount of magnetic flux is increased.

[0007]

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an outer rotor type including a stator having a winding mounted on an iron core having a plurality of slots, and a permanent magnet rotor rotatably disposed opposite to a magnetic pole surface of the stator. In a permanent magnet motor,
The permanent magnet constituting each pole is a central main magnet,
An auxiliary magnet having magnetic poles perpendicular to the magnetic pole direction of the main magnet is disposed at both ends of the auxiliary magnet.
t array can be applied.

The length of the auxiliary magnet is 0.03 to 0.2 times the opening angle (360 degrees / number of poles) constituting each pole.

Further, the main magnet may be divided into a plurality of parts, and the magnetic poles may be arranged so that the magnetic flux concentrates at the pole center.

In the case where the permanent magnets constituting the respective poles are the main magnet at the center and the auxiliary magnets having magnetic poles perpendicular to the magnetic pole direction of the main magnet at both ends, the magnetic flux generated by the permanent magnets Since the amount can be increased, the magnet torque generated by the same current is more effectively generated. Further, since the amount of magnetic flux generated is larger than in the conventional magnet arrangement, and the magnetic flux is concentrated at the pole center, it is possible to cover the loss due to the magnetic flux wraparound generated at both ends of the permanent magnet. Further, since the magnetic flux can be generated more strongly in the inner circumferential direction than in the outer circumferential direction of the rotor, the magnetic flux density of the rotor core can be reduced, so that the rotor core can be thinned. further,
With the same output, the size of the motor can be reduced.

[0011]

FIG. 7 is a sectional view in the axial direction of the motor, in which 5 is a shaft, and 4 is a stator winding wound around the stator. The stator 3 includes a predetermined number of teeth,
A stator winding 4 is arranged between the teeth. When an alternating current is applied to the stator winding, a rotating magnetic field is generated, and the rotating magnetic field drives the rotor 1 to rotate.

In FIG. 1, a rotor 1 has a rotor core 1a made of a material having a high magnetic permeability and permanent magnets 2 arranged so that N poles and S poles are alternately arranged. Each of the permanent magnets is formed in an arc shape along the inner circumference of the rotor, and an auxiliary magnet 2b having a magnetic pole in a direction perpendicular to the magnetic pole direction of the main magnet 2a is disposed at each end.

With such a configuration, the outer rotor type permanent magnet motor of the present invention is a Halbach magnet array.
Can be applied. Halbach magnet here
The array will be described with reference to FIG. FIG. 4 (a)
Is a magnet arrangement when the rotor of the four-pole motor is represented in a plane. Normally, the north pole and the south pole are alternately arranged in this manner. The magnetic flux flows as 1a, 2a..., 1b, 2b,. FIG. 4B shows a magnet having magnetic poles in a direction perpendicular to the main magnet shown in FIG. The magnets are arranged such that the same polarity opposes. The flow of the magnetic flux is as shown in 6a, 7a,..., 6b, 7b,. FIG. 4 (c) is a combination of the magnet of FIG. 4 (a) and the magnet of FIG. 4 (b). Thus, by adjoining the magnets whose magnetic poles are in a vertical relationship, 2b and 7
b, 3b and 8b, 4b and 9b strengthen each other, 2a
And 7a, 3a and 8a, 4a and 9a weaken each other.
Therefore, as shown in FIG.
It becomes stronger than when a normal magnet arrangement is used. In this way, the magnetic force can be increased in any direction.

If the length of the auxiliary magnet is short, the force for holding down the magnetic flux of the main magnet from both ends is weakened.
Agnet array does not work. Further, if the length of the auxiliary magnet is long, the amount of magnetic flux generated by the main magnet decreases. FIG. 5 shows the torque characteristics with respect to the length of the auxiliary magnet. From this figure, it is appropriate that the length θh of the auxiliary magnets disposed at both ends of the main magnet is 0.03 to 0.2 times the opening angle θ constituting each pole.

FIG. 6 shows the magnetic flux density distribution at the air gap between the case where the Halbach magnet array is applied and the conventional magnet arrangement. As shown in the figure, it can be seen that the amount of magnetic flux is increased by the Halbach magnet array.

FIGS. 2 and 3 show another embodiment.
FIG. 2 shows a magnet arrangement in the case where the permanent magnets constituting each pole are 180 degrees or less in electrical angle. In FIG. 3, the permanent magnets constituting each pole are divided into a plurality of magnets, and the magnets are arranged so that the magnetic flux is concentrated at the pole center.

Although the embodiment relates to an 8-pole outer rotor type permanent magnet motor, the number of poles is not limited.

[0018]

As is clear from the description of the above embodiment,
According to the present invention, since the amount of magnetic flux generated by the permanent magnet is increased by using the same amount of permanent magnet as in the related art, more magnet torque can be used. Further, since the magnetic flux of the permanent magnet can be generated more on the inner circumferential side (air gap side) than on the outer circumferential side of the rotor, the magnetic flux density of the rotor core can be reduced and the rotor core can be thinned.

Further, a motor having the same output as that of the conventional motor can be made small and lightweight. As a result, a high-torque, high-output, compact and lightweight motor can be provided.

[Brief description of the drawings]

FIG. 1 is a sectional view of a motor showing a first embodiment of the present invention.

FIG. 2 is a sectional view of a motor showing another embodiment of the present invention.

FIG. 3 is a sectional view of a motor showing another embodiment of the present invention.

4A is a diagram illustrating a magnetic flux of a main magnet. FIG. 4B is a diagram illustrating a magnetic flux of an auxiliary magnet. FIG. 4C is a diagram illustrating a Halbach magnet array.

FIG. 5 is a diagram showing length-torque characteristics of an auxiliary magnet;

FIG. 6 is a magnetic flux density distribution diagram.

FIG. 7 is a sectional view of a motor according to the present invention.

FIG. 8 is a sectional view of a conventional motor.

[Explanation of symbols]

 Reference Signs List 1 rotor 1a rotor core 2 permanent magnet 2a main magnet 2b auxiliary magnet 3 stator

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Mikio Hirano 1006 Kazuma Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (5)

[Claims] 1. An outer rotor type permanent magnet motor comprising: a stator having windings mounted on an iron core having a plurality of slots; and a permanent magnet rotor rotatably disposed opposite to a magnetic pole surface of the stator. The outer rotor type permanent magnet motor according to claim 1, wherein the permanent magnets constituting the poles include a central main magnet and auxiliary magnets having magnetic poles perpendicular to the magnetic pole direction of the main magnet at both ends. 2. The outer rotor type permanent magnet according to claim 1, wherein the length of the auxiliary magnet per pole is 0.03 to 0.2 times the opening angle of the permanent magnet forming each pole. motor. 3. The outer rotor type permanent magnet motor according to claim 1, wherein the main magnet is divided into a plurality of magnets, and the magnetic poles thereof are arranged so that magnetic flux is concentrated at the center of the poles. 4. A washing machine using the motor according to claim 1. 5. A dishwasher / dryer using the motor according to claim 1.