JPH11308824A - Magnetization method of permanent magnet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetization method and magnetization device of a permanent magnet by which a perfect magnetization level intensity is achieved, while a waveform for magnetization such as a sine wave, etc., is controlled. SOLUTION: Protruding parts 16a and recessed parts 16b are provided on the surface of an auxiliary yoke 12 on a permanent magnet side material 11. A magnetization yoke 13 is provided on the side of the permanent magnet material 11 opposite to the side facing the auxiliary yoke 12. As a result of this constitution, The magnetism inducing direction of a whole magnet can be controlled by the positions of the protruding parts 16a and angles between the protruding parts 16a in a circumferential direction, so that an arbitrary waveform such as a sine wave, etc., of a magnetic flux density can be obtained without causing decline in a magnetization intensity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for magnetizing a permanent magnet used in an actuator such as a motor.

[0002]

2. Description of the Related Art A conventional method of magnetizing a permanent magnet includes a magnetizing yoke in which a magnetizing coil for generating a magnetizing magnetic field is wound in order to completely magnetize a magnet material. An auxiliary yoke made of a magnetic material is arranged at a position opposite to the permanent magnet material to be magnetized. The auxiliary yoke serves to draw the magnetizing magnetic field generated by the magnetized yoke to a deep portion of the magnet material.
It is possible to induce magnetization over the entire region of the magnet material and magnetize it to the maximum level of the magnet material. That is, the magnet material can be completely magnetized, but at this time, the magnetic flux density generated in the air gap of the motor when the permanent magnet is assembled to the motor necessarily has a trapezoidal or rectangular wave shape. Was.

Therefore, for example, when it is desired to make the magnetic flux density waveform generated in the air gap of the motor into a sine wave shape, the auxiliary yoke is removed to make it difficult for the magnetizing magnetic field to flow deep into the magnet material.

As described above, in the conventional magnetizing method, when a desired magnetic waveform is applied to an electric device such as a motor using a magnet surface magnetic flux density waveform after magnetizing, the magnet material is partially magnetized. Needed.

[0005]

However, when the sine-wave magnetizing of the magnet material is performed by the above-described method, the magnet material is partially magnetized.
There is a problem that the amount of magnetic flux generated by the permanent magnet is reduced.

The present invention is to solve such a conventional problem, and performs waveform control such as sine waveform magnetization.
It is an object of the present invention to provide a method and apparatus for magnetizing a permanent magnet having a strength of a complete magnetization level.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a magnetized yoke having a magnetized coil wire disposed in a slot, and a magnetized yoke opposite to the magnetized yoke across a permanent magnet material. An auxiliary yoke that is positioned, and the auxiliary yoke facing the permanent magnet material is a method of magnetizing a permanent magnet in which the auxiliary yoke is provided with an uneven portion, and the entire region of the magnet material is magnetized in an optimal state. For example, it is possible to eliminate a decrease in the magnetization intensity that occurs when arbitrary waveform control represented by, for example, a sine waveform magnetization is performed.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention comprises a magnetized yoke having a magnetized coil wire disposed in a slot, and an auxiliary yoke located on the opposite side of the magnetized yoke with a permanent magnet material interposed therebetween. This is a method of magnetizing a permanent magnet that is magnetized in a state in which the auxiliary yoke facing the magnet is provided with an uneven portion.

Further, the structure is such that the permanent magnet material and the projection of the auxiliary yoke are in close contact with each other. Further, the configuration is such that a concave portion of the auxiliary yoke is provided at a position facing the slot of the magnetized yoke.

[0010] Further, a projection of the auxiliary yoke is provided at a position facing the slot of the magnetized yoke.

[0011] Further, the auxiliary yoke has a configuration in which the convex portion is brought into close contact with the permanent magnet material. Further, the auxiliary yoke has a configuration in which a convex portion, a permanent magnet material, and a predetermined gap are provided.

Further, the auxiliary yoke is provided with a concave portion on the same normal line as the slot of the magnetized yoke, and the ratio of the convex portion of the auxiliary yoke is set to 0.8 or more.

[0013] Further, the auxiliary yoke is provided on the same normal line as the slot of the magnetized yoke, and the ratio of the auxiliary yoke recess is set to 0.3 or more.

Further, the auxiliary yoke is made of a magnetic metal. Further, the auxiliary yoke is made of a thin plate made of a magnetic material and has a laminated structure.

As described above, with the auxiliary yoke provided with the concavo-convex portion, a magnetizing magnetic field can be induced in the convex portion of the auxiliary yoke and generated by the magnetizing coil in accordance with the position and size of the convex portion. It is possible to control the direction and direction of magnetization of the permanent magnet as a result of inducing and rotating the magnetic moment in the magnet material in the desired direction. , And finally an arbitrary shape of magnetization can be realized.

Further, by providing a concave portion of the auxiliary yoke at a position facing the slot of the magnetized yoke, it is possible to magnetize a sinusoidal waveform.

By providing a projection of the auxiliary yoke at a position facing the slot of the magnetized yoke, trapezoidal waveform or rectangular waveform magnetization is possible.

Further, by providing the auxiliary yoke with irregularities and laminating the auxiliary yoke with a magnetic material, the eddy current in the auxiliary yoke induced by the magnetization magnetic field can be reduced, and the magnetization magnetic field can be used efficiently. It can be magnetized with energy saving.

In the case where the auxiliary yoke is provided with irregularities, the magnetic path of the magnetizing magnetic field can be determined with high accuracy, so that extremely stable permanent magnet magnetization with no variation is possible.

[0020]

(Embodiment 1) FIG. 1 shows a method of magnetizing a permanent magnet according to a first embodiment of the present invention.

In FIG. 1, reference numeral 11 denotes a permanent magnet material, 12 denotes an auxiliary yoke, and 13 denotes a magnetized yoke. Permanent magnet material 11
Are arranged with a predetermined gap from the magnetized yoke 13. The magnetized yoke 13 is made of a magnetic material such as an electromagnetic steel plate or pure iron. The magnetized yoke 13 is wound with a magnetized coil 14 for at least one turn.
4 is connected to a magnetizing power supply to generate a magnetizing magnetic field for magnetizing the permanent magnet material 11.

The auxiliary yoke 12 is made of a magnetic material such as an electromagnetic steel plate or pure iron, and is disposed on the side opposite to the magnetized yoke 13 via the permanent magnet material 11. A projection 16a and a recess 16b are provided on the surface of the auxiliary yoke 12 on the permanent magnet material 11 side, and the projection 16a is arranged with the permanent magnet material 11 via a predetermined gap. Auxiliary yoke 12
The center of the convex portion 16a is disposed on the same normal line as the center of the slot provided in the magnetized yoke 13, that is, the center of the magnetized coil 14.

A description will be given of a method of magnetizing the permanent magnet according to the present embodiment configured as described above.

A magnetizing magnetic field generated by applying a current to the magnetizing coil 14 crosses the permanent magnet material 11 and flows in the direction of the auxiliary yoke 12. At this time, when viewed from the magnetized yoke 13, the protrusion 16a has a low magnetic resistance, and
b has a high magnetic resistance. Therefore, the magnetizing magnetic field is more likely to flow to the convex portion 16a than to the concave portion 16b. Since the magnetized state of the permanent magnet material 11 depends on the distribution of the magnetizing magnetic field, the permanent magnet material 11 is determined by the position and the size of the projection 16a.

In the case of this embodiment shown in FIG.
The magnetic flux density distribution generated on the surface of the magnetized yoke 13 by
It has a trapezoidal wave shape. Incidentally, in the present embodiment, when magnetizing in a trapezoidal wave shape, the ratio of the angular width in the circumferential direction between the convex portion 16a and the concave portion 16b is set to 8: 2, or the ratio of the convex portion 16a is made larger than 8. good.

Further, when the magnetized permanent magnet material 11 is incorporated in a motor, the magnetic flux density waveform in the air gap of the motor can be freely designed depending on the positions and sizes of the convex portions 16a and the concave portions 16b. Further, in this embodiment, since the entire magnetization inside the permanent magnet can be magnetized in the optimal direction and strength,
The performance inherent in permanent magnet materials can be used to the maximum. In the present embodiment, the effect of the present invention can be more reliably obtained if the magnetizing magnetic field is set to be large enough to completely magnetize the permanent magnet material 11.

It is sufficient that the depth of the convex portion 16a and the concave portion 16b in the normal direction is equal to or longer than the minimum distance between the magnetized yoke 13 and the auxiliary yoke 12. Also,
The shape of the convex portion 16a and the concave portion 16b is the depth in the normal direction,
There is no particular limitation as long as the ratio of the angular width in the circumferential direction is the above-mentioned value.

In this embodiment, a predetermined gap is provided between the convex portion 16a and the permanent magnet material 11. However, the present invention is not limited to this, and the convex portion 16a and the permanent magnet material 11 may be in close contact. .

(Embodiment 2) FIG. 2 shows a method of magnetizing a permanent magnet according to a second embodiment of the present invention.

In FIG. 2, the center of the projection 16a provided on the auxiliary yoke 12 is arranged on the same normal line as the center of the magnetized coil 14.

According to the method of magnetizing the permanent magnet in the present embodiment configured as described above, the magnetizing magnetic field easily flows in the direction of the convex portion 16a, and the magnetic moment in the permanent magnet material 11 is It can be guided in an optimal direction so that the subsequent surface magnetic flux density waveform becomes a sine waveform. At this time, the ratio of the angular width in the circumferential direction between the convex portion 16a and the concave portion 16b may be set to 3: 7, or the ratio of the convex portion 16a may be set to 3 or more.

Although the present invention has been described with respect to a configuration in which the inner peripheral side of the permanent magnet is magnetized and a gap is provided between the outer peripheral side of the permanent magnet and the auxiliary yoke, the present invention is not limited to this. For example, it goes without saying that the present invention can be applied to a configuration in which the outer peripheral side of the permanent magnet is magnetized, the auxiliary yoke is arranged on the inner peripheral side of the permanent magnet, and the auxiliary yoke is provided with irregularities.

The permanent magnet material does not need to be ring-shaped. For example, a plurality of C-shaped magnets may be used and arranged in a ring shape. There is no limitation on the material of the permanent magnet material, and the present invention can be applied. The magnetized yoke and the auxiliary yoke are not particularly limited as long as they are magnetic materials. Further, the magnetized yoke and the auxiliary yoke may have a laminated structure or a non-laminated structure.

[0034]

According to the first aspect of the present invention, since the auxiliary yoke is provided with irregularities, the magnetic flux density waveform can be freely designed to have an arbitrary waveform. In addition, since the entire magnetization inside the permanent magnet can be magnetized in the optimal direction and strength, the performance unique to the permanent magnet material can be used to the maximum, and the energy of the magnetizing magnetic field can be reduced. Also leads to Also,
When the auxiliary yoke is provided with irregularities, the magnetic path of the magnetizing magnetic field can be determined with high accuracy, and therefore, extremely stable permanent magnet magnetization without variation is possible.

According to the embodiment of the present invention, the surface magnetic flux density waveform of the permanent magnet can be formed into a trapezoidal waveform.

According to the third embodiment, the surface magnetic flux density waveform of the permanent magnet can be made sinusoidal. In particular, it is possible to perform sine waveform magnetization without lowering the intensity of the magnetic flux density than when trapezoidal or rectangular waves are used.
Therefore, when the magnetized permanent magnet is used for the motor, the air gap of the motor can be made sinusoidal without lowering the output of the motor, and the torque pulsation is small.
A low-vibration motor can be realized.

Further, according to the embodiment of the present invention, since the projection of the auxiliary yoke can be in close contact with the permanent magnet material, the required magnitude of the magnetizing magnetic field can be minimized.

According to the ninth embodiment, since the magnetic body has a laminated structure, the generation of an eddy current induced in the magnetizing magnetic field and flowing in the auxiliary yoke can be suppressed. The magnitude of the magnetic field can be minimized.

According to the eleventh embodiment, since the magnetization waveform can be freely designed according to the shape of the iron core of the motor, the cogging torque generated in the motor can be easily reduced, and the winding of the motor can be reduced. Can be optimized with respect to the waveform of the current flowing through the winding, so that a low-vibration motor with small torque ripple can be realized. Further, since the permanent magnet material can be completely magnetized and the magnetization waveform can be optimally controlled, the motor can be reduced in size and a highly efficient motor with less magnetic loss can be realized.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a magnetizing method according to a first embodiment of the present invention.

FIG. 2 is an explanatory view showing a magnetizing method according to a second embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 11 permanent magnet material 12 auxiliary yoke 13 magnetized yoke 14 magnetized coil 15 air gap 16a convex portion 16b convex portion 17 slot

Claims (11)

[Claims] 1. A magnetized yoke having a magnetized coil wire disposed in a slot, and an auxiliary yoke located on the opposite side of the magnetized yoke with a permanent magnet material interposed therebetween, and an auxiliary yoke facing the permanent magnet material is provided. A method of magnetizing a permanent magnet that is magnetized in a state in which the yoke is provided with an uneven portion. 2. The method for magnetizing a permanent magnet according to claim 1, wherein the magnet is magnetized in a state in which a recess of the auxiliary yoke is provided on the same normal line as the slot of the magnetized yoke. 3. The method for magnetizing a permanent magnet according to claim 1, wherein the magnet is magnetized in a state where a projection of the auxiliary yoke is provided on the same normal line as a slot of the magnetized yoke. 4. The method for magnetizing a permanent magnet according to claim 1, wherein the magnetizing is performed in a state where the convex portion of the auxiliary yoke is in close contact with the permanent magnet. 5. The method for magnetizing a permanent magnet according to claim 1, wherein the convex portion of the auxiliary yoke is provided so as to have a predetermined gap with the permanent magnet. 6. The permanent magnet according to claim 1, wherein the concave portion of the auxiliary yoke is provided on the same normal line as the slot of the magnetic yoke, and the ratio of the convex portion of the auxiliary yoke is set to 0.8 or more. Magnetization method. 7. The permanent magnet as claimed in claim 1, wherein the auxiliary yoke is provided with a convex portion on the same normal line as the slot of the magnetic yoke and the ratio of the auxiliary yoke concave portion is set to 0.3 or more. Magnetic method. 8. The method for magnetizing a permanent magnet according to claim 1, wherein the auxiliary yoke is made of a metal material that is a magnetic material. 9. The method for magnetizing a permanent magnet according to claim 1, wherein the auxiliary yoke is formed by laminating thin plates made of a magnetic material. 10. A permanent magnet, wherein a permanent magnet material is magnetized by the method for magnetizing a permanent magnet according to claim 1. 11. A spindle motor for optical media using a permanent magnet magnetized by the method for magnetizing a permanent magnet according to claim 1.