JP2002199669A - Magnetizing method for permanent magnet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure sinusoidal magnetized field on a segment magnet and to complete assembly of a rotor before magnetizing with fixing a not-magnetized magnet to the rotor. SOLUTION: The rotor is composed of segment magnets 10, soft magnetic members 13, non-magnetic members 14 and a rotor shaft 15, and a magnetic-field applying part composed of a coil 12 and a yoke 11 rotatable in the outer circumference direction of the rotor is placed. With assembling the rotor before magnetizing and with removing the applying part after magnetizing, a motor together with a stator can be assembled. A magnetic field of a magnet inner circumference side is ensured by the magnetic members 13 between segment magnets 10, the magnetic field from the coil 12 is entered into the shaft 15, which is a magnetic material, through the magnetic members 13. The non-magnetic members 14 ensure the magnetic field at the inner circumference side and also at central part of the segment magnets 10 and satisfy the angle of the magnetic field. According to the invention, sinusoidal magnetizing is allowed with making a piece of a divided permanent magnet be one pole.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of magnetizing a permanent magnet, and more particularly to a method of magnetizing a divided permanent magnet that can be used in a permanent magnet motor.

[0002]

2. Description of the Related Art Japanese Patent Application No. Hei 10-93096 discloses a method of magnetizing a permanent magnet with a sine wave. In order to control the waveform of the sine wave magnetization and to achieve the strength of the complete magnetization level, it is possible to magnetize to a deep portion of the magnet material by magnetizing with a space between the permanent magnet and the auxiliary yoke. It is written. It also states that the direction of the magnetic field generated by the magnetizing coil can be controlled according to the space length.

[0003] In the above magnetizing method, it is expected that the magnetizing magnetic field becomes insufficient in the case of magnetizing a segment magnet having a large radial thickness. Further, in the above-described magnetizing method, since the coil is arranged on the inner peripheral side of the ring magnet, a step of assembling the magnet into the rotor after magnetizing is required.

As described above, in the conventional invention, the arc-shaped segment magnet is arranged on the rotor in a non-magnetized state, and then magnetized by the coil outside the magnet, and sine wave magnetization is also realized. It is not shown.

[0005] A rotor for a motor using an arc segment magnet is described in Japanese Patent Application No. Hei 6-132603. FIG. 1 of Japanese Patent Application No. 6-132063 shows a configuration in which N-pole segments and S-pole segments are stuck alternately in the outer circumferential direction.

[0006] However, these publications do not disclose a method of magnetizing the segments or a process of assembling the magnets. Further, there is no disclosure of disposing a soft magnetic member between sine-wave magnetized segment magnets.

[0007]

The above-mentioned prior art relates to an arc segment magnet in which one pole is one segment.
There is no description of a magnetizing method for obtaining a sufficient magnetizing magnetic field by sine wave magnetization or a factor to be suppressed for realizing sine wave magnetization.

[0008] Therefore, not only a magnetizing method for mass-producing a rotor using one pole and one segment is disclosed, but also a magnetizing method particularly for an isotropic magnet requiring a magnetizing magnetic field has been established. Not.

In order to mass-produce a rotor using arc segment magnets, it is necessary to magnetize the magnet after assembling the rotor. When magnetizing, it is desirable that the assembly of the magnet part of the rotor is completed.

In the case of a segment magnet, the assembly process after magnetizing is not as simple as that of a ring magnet. A magnetizing method for solving such a problem has not been described so far.

An object of the present invention is to secure a magnetizing magnetic field of an arc segment magnet, to make the surface magnetization direction close to a sine wave, and to fix an unmagnetized magnet to a rotor.
It seems that the rotor has already been assembled before magnetization,
An object of the present invention is to provide a method for magnetizing a permanent magnet.

[0012]

SUMMARY OF THE INVENTION The object of the present invention is to assemble a rotor that satisfies the magnetizing conditions before magnetizing, apply a magnetizing magnetic field to the rotor from outside the rotor, and use a soft magnetic material between segment magnets. Can be achieved by using a non-magnetic material on the radially inner side of the segment magnet, and adjusting the position of the coil for applying the magnetic field.

That is, when a plurality of permanent magnets arranged in the circumferential direction of the rotor of the motor are magnetized, a ferromagnetic material is applied between the permanent magnets and between the rotor shaft and the yoke outside the rotor. A member is disposed, a non-magnetic portion is provided between the permanent magnet and the rotor shaft, and the yoke outside the rotor or the rotor shaft is rotated to be magnetized.

For example, a permanent magnet can be divided and one can be magnetized sinusoidally with one pole as a pole. The permanent magnet can be magnetized after assembling the permanent magnet between the ferromagnetic members in advance. . Further, the ferromagnetic member and the non-magnetic member between the magnet and the rotor shaft can be exchanged for a material different from the material being magnetized.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a basic configuration diagram.
The rotor is an arc segment magnet 10, a soft magnetic member 13,
It is composed of a non-magnetic member 14 and a rotor shaft 15, and a magnetic field application unit composed of a coil 12 and a yoke 11 is provided outside the rotor. This magnetic field applying unit can be rotated in the circumferential direction.

Before the magnetization, the rotor of FIG. 1 is assembled, and after the magnetization, only the magnetic field applying unit is removed to provide a rotor, and the rotor is assembled with the stator. By using the rotor having such a configuration, it is possible to assemble the rotor before magnetization.

The reason why the soft magnetic member 13 is disposed between the divided arc segment magnets (simply called segment magnets) 10 is to secure a magnetic field on the inner peripheral side of the magnet. The magnetic field from the coil 12 passes through the yoke 11, passes through the soft magnetic member 13, and enters the shaft, which is a magnetic material. In the case of the opposite direction, the magnetic field is in the opposite direction.

When the soft magnetic member 13 is not provided, the yoke 1
The magnetic field from 1 becomes small on the inner peripheral side of the segment magnet 10, and it becomes difficult to magnetize the entire segment magnet.
The reason why the non-magnetic member 14 is used on the inner peripheral side of the segment magnet 10 is to secure the magnetic field on the inner peripheral side and the central portion of the segment magnet 10 and satisfy the angle of the magnetic field.

Next, the member materials used in FIG. 1 will be described. The segment magnet 10 is an NdFeB isotropic magnet, a SmFeN isotropic magnet, or an anisotropic magnet.
The magnetic field required for magnetization is 20 kOe in the case of an NdFeB isotropic magnet. The magnetic member 13 is an Fe-based material having a low coercive force and a high saturation magnetic flux density. The non-magnetic member 14
A Cu-based alloy or an Al-based alloy is used.

In the rotor shown in FIG. 1, the materials of the non-magnetic member 14 and the soft and soft magnetic member 13 can be changed before and after magnetization. For example, the non-magnetic member 14 can be magnetized using eddy current as a conductive non-magnetic material such as Cu during magnetization, and can be made of a ferromagnetic material such as soft iron after magnetization.

Alternatively, the soft magnetic member 13 may be made of an expensive FeCo alloy having a high saturation magnetic flux density during magnetization, and an inexpensive silicon steel sheet may be used after magnetization. Non-magnetic member 1
4 can also be changed from a resin or the like to a metal material after magnetization. These are determined in terms of adhesion to the magnet, securing strength during rotation, and the like.

On the outer periphery of the segment magnet 10, there is a magnetic field applying section comprising a coil 12 and a yoke 11. The coil 12 is arranged symmetrically with respect to the center of the segment magnet 10, and the direction and distribution of the magnetic field in the segment magnet 10 change depending on the position of the coil 12.

FIG. 2 is an enlarged view of the magnetic field applying yoke outside the rotor in FIG. Six conductive wires serving as coils are arranged. The distances from the circumferential end of the yoke 11 to the second coil 122 and the first coil 121 are x1 and x2, respectively.

At this time, the distances from the circumferential ends of the second coil 122 and the third coil 123 are equal. The distance from the radial end of the third coil 123 is x3, the first coil 1
The distance from the radial end of 21 is x4.

In FIG. 1, it is shown in FIG. 6 that the angle of the magnetic flux at the positions A, B, and C at the circumferential end of the segment magnet 10 depends on x1. Angle is 90
In the case of degrees, it becomes a magnetic flux in the circumferential direction. In order to realize sine wave magnetization, an angle of 90 ° is particularly necessary at C on the magnet surface side.
It is better to be close to the degree. Therefore, the optimal x1 is about 1 mm
Becomes

When the position A is moved in the circumferential direction in the segment magnet, the fluctuation of the magnetic field depends on x4, and the result is as shown in FIG. From this result, the first coil 121
It can be seen that the position from the radial end is more distant than the third coil 123.

X3 affects the magnetic field strength, and x2 affects the magnetic field strength and angle. As described above, it is necessary to design the three coil positions at optimal positions according to the magnet shape and the magnetizing magnetic field.

FIG. 3 shows an example in which a soft magnetic member 31 is provided on the surface of the rotor portion shown in FIG. The soft magnetic member 31 used is F
It is an e-system high saturation magnetic flux density material. Also in this example, it is possible to perform sinusoidal magnetization on the segment magnet.

FIG. 4 shows an example of a countermeasure when the magnetic field at the end of the magnet is not sufficient in FIG. 1. The width of the soft magnetic member 41 differs in the radial direction, and becomes wider toward the center. With such a structure, the magnetic flux from the coil 12 easily leaks to the inner peripheral side, and the magnetic field on the inner peripheral side of the segment magnet 10 increases.

FIG. 5 shows an example in which the rotor of FIG. The segment magnets 10 and the soft magnetic members 13 are alternately arranged on the gap side. According to this example, each segment magnet is magnetized in a sinusoidal manner when magnetized by the soft magnetic member 13, so that a high level and deep magnetizing is performed, and a highly efficient motor can be obtained. .

[0031]

As described above, by using the permanent magnets divided and arranged in the circumferential direction of the rotor of the motor, one permanent magnet is used as one pole, and the space between the divided permanent magnets and the rotation of the rotor shaft. A ferromagnetic material is placed between the outer yokes, a non-magnetic part is provided between the magnet and the rotor shaft, and the coil or yoke on the outer rotor or the rotor shaft is rotated to form a sinusoidal attachment of the permanent magnet. Magnetism becomes possible.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a magnetized yoke viewed from a cross section of a rotor according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a yoke outside a rotor used for magnetization according to an embodiment of the present invention.

FIG. 3 is a configuration diagram of a magnetized yoke viewed from a cross section of a rotor according to another embodiment of the present invention.

FIG. 4 is a configuration diagram of a magnetized yoke viewed from a cross section of a rotor according to still another embodiment of the present invention.

FIG. 5 is a diagram showing an example in which the rotor according to the present invention is incorporated in a stator.

FIG. 6 is a diagram showing a relationship between a coil position and an angle of a segment magnet end magnetic flux in the present invention.

FIG. 7 is a diagram showing a relationship between a coil position and a magnetic field distribution in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Gment magnet 11 Yoke 12 Coil 13 Soft magnetic member 14 Non-magnetic member 15 Shaft 31 Soft magnetic member 41 Soft magnetic member 121 First coil 122 Second coil 133 Third coil

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Junya Kanada 7-1-1, Omikacho, Hitachi City, Ibaraki Prefecture Inside Hitachi, Ltd. Hitachi Research Laboratory, Ltd. (72) Inventor Motoya Ito 7-1 Omikamachi, Hitachi City, Ibaraki Prefecture No. 1 F-term in Hitachi Research Laboratory, Hitachi Ltd. (Reference) 5H002 AA05 AA07 AB07 AC06 AE08 5H622 CA02 CA05 CB04 DD02 PP07 QB04 QB10

Claims (8)

[Claims] When a plurality of permanent magnets arranged in a circumferential direction of a rotor of a motor are magnetized, a ferromagnetic material is provided between the permanent magnets and between a rotor shaft and a yoke outside the rotor. A method for magnetizing a permanent magnet, comprising: arranging a member, providing a non-magnetic portion between the permanent magnet and a rotor shaft, and rotating the yoke or the rotor shaft outside the rotor to magnetize the rotor. 2. A permanent magnet which is divided and arranged in a circumferential direction of a rotor of a motor, and when one of the divided permanent magnets is magnetized as one pole, between the permanent magnets and A ferromagnetic member is arranged between the rotor shaft and the yoke outside the rotor, a non-magnetic portion is provided between the permanent magnet and the rotor shaft, and the yoke or the rotor shaft outside the rotor is rotated. A method of magnetizing a permanent magnet, comprising: magnetizing. 3. When permanent magnets divided and arranged in the circumferential direction of a rotor of a motor are used, and when one divided permanent magnet is used as one pole and magnetized sinusoidally, the permanent magnets are separated from each other. A ferromagnetic member is disposed between the permanent magnet and the rotor shaft, and a non-magnetic portion is provided between the permanent magnet and the rotor shaft. A method of magnetizing a permanent magnet, characterized in that the magnet is rotated and magnetized. 4. A permanent magnet which is divided and arranged in the circumferential direction of a rotor of a motor, and the permanent magnet is set in advance before magnetizing sinusoidally with one divided permanent magnet as one pole. Is fixed to a rotor, a ferromagnetic member is provided between a rotor shaft and a yoke outside the rotor, and the yoke or the rotor shaft is rotated to magnetize the permanent magnet. 5. A rotor shaft, a ferromagnetic plate radially arranged from the rotor shaft, a permanent magnet provided between the ferromagnetic plates, and a space between the permanent magnet and the rotor shaft. The permanent magnet is sinusoidally magnetized by relatively moving a coil and the rotor shaft, which are constituted by an installed non-magnetic member and disposed outside the permanent magnet. How to magnetize permanent magnets. 6. In the case of using a permanent magnet divided and arranged in the circumferential direction and magnetizing sinusoidally with one of the divided permanent magnets as one pole, rotation and rotation between the divided permanent magnets are performed. A ferromagnetic member is provided between the rotor shaft and the yoke on the outer side of the rotor, and a non-magnetic portion is provided between the magnet and the rotor shaft. After the magnetization, the non-magnetic member or the ferromagnetic member is different from the member being magnetized. A method of magnetizing a permanent magnet, which is replaceable with a material. 7. A rotor having a permanent magnet magnetized by the magnetizing method according to claim 1. Description: 8. A motor comprising the rotor according to claim 7.