JP2508093Y2 - Magnetizing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a magnetizing device for magnetizing and magnetizing a magnetic material in order to obtain a permanent magnet used for a stator of a DC motor.

[Prior Art] Conventionally, a permanent magnet used for a stator of a DC motor is
It is manufactured by a magnetizing device as shown in FIG.

Specifically, the rotating armature 20 is arranged in a motor main body 21 that serves as a yoke so that the assembled state as a motor is obtained, and the magnetic bodies 22, 23 for permanent magnets are provided on the inner circumference of the motor main body 21. Place and fix. Then, magnetizing iron cores 24 and 25 are installed in contact with the outer peripheral surfaces of the motor main body 21 where the magnetic bodies 22 and 23 are located, respectively, and field coils 26 and 27 are wound around the magnetizing iron cores 24 and 25, respectively. Keep turning.

When using this magnetizing device, each field coil 26, 27
To the S pole on the inner peripheral surface of the magnetizing core 24, and the magnetizing core 25
An N pole is generated on the inner peripheral surface of the.

The magnetic flux generated by the N pole magnetizing iron core 25 flows from the inner peripheral surface of the iron core 25 to the outer peripheral surfaces of the motor body 21 and the magnetic body 23, and inside the magnetic body 23 flows upward in the drawing. Further, the magnetic flux flows from the inner peripheral surface of the magnetic body 23 to the inner peripheral surfaces of the rotating armature 20 and the magnetic body 22, and flows inside the magnetic body 22 upward in the drawing.
This magnetic flux flows from the outer peripheral surface of the magnetic body 22 to the motor body 21 and the iron core 24.

By energizing for a predetermined time, the magnetic bodies 22 and 23 are magnetized, magnetic poles appear on the inner and outer peripheral surfaces, and permanent magnets are obtained.

FIG. 4 shows the magnetized state of the permanent magnet 28 obtained from the magnetic body 22. An N pole appears on the outer peripheral surface of the permanent magnet 28 and an S pole appears on the inner peripheral surface. Magnetic pole neutral 29
Is located in the middle of the inner and outer peripheral surfaces. Therefore, the magnetization direction is a uniform direction parallel to the center normal line. The permanent magnet obtained by the magnetic body 23 has an S
It is magnetized so that a pole appears and an N pole appears on the inner peripheral surface, and the magnetic pole center line is at the same position as the permanent magnet 28.

In the above-mentioned magnetizing device, a desired DC motor is obtained by removing the magnetizing iron cores 24 and 25 after magnetizing.

As shown in FIG. 3, in a small DC motor, flat portions 21a, 21a are formed on a part (side surface side) of the motor body 21 in order to downsize the motor.

In this DC motor, magnetic flux flows from the inner peripheral surface (N pole) of the permanent magnet obtained by the magnetic body 23 to the rotating armature 20, and then the inner peripheral surface (S of the permanent magnet obtained by the magnetic body 22 (S To the pole). Further, the magnetic flux passes through the permanent magnet and flows from the outer peripheral surface (N pole) to the arc-shaped portion of the motor main body 21.
The magnetic flux flowing in the arc-shaped portion flows from the bent portion of the motor main body 21 through the flat portion 21a to the other arc-shaped portion, and the magnetic body 23
It flows into the inside from the outer peripheral surface (S pole) of the permanent magnet obtained in.

[Problems to be Solved by the Invention] In the above-described DC motor, the contact surface between the outer peripheral surface of the permanent magnet and the inner peripheral surface of the motor body constitutes a part of a magnetic circuit, and the contact surface forms the magnetic resistance. Therefore, it is necessary to contact them without any gap so as not to increase. However, in the process of firing powder such as ferrite during molding of the permanent magnet,
Since the dimensional change of the magnet occurs, it is necessary to grind the outer peripheral surface of the permanent magnet to improve the shape accuracy, and further, the inner peripheral surface of the motor body is also required to have high processing accuracy.
Therefore, in the conventional DC motor, the number of work steps is increased,
There is a problem that work efficiency during manufacturing is not good due to complication.

Further, in order to reduce the size of the motor, in a case where a part of the motor body is flattened, a bent portion is formed at the boundary between the arc-shaped portion and the flat portion of the motor body. This bending portion has a large drawing ratio, and the magnetic resistance increases due to the processing. In a DC motor using the motor body as a yoke, the effective magnetic flux decreases due to the bending portion, which reduces the motor performance. There is also.

Further, the permanent magnet used in the DC motor has its inner peripheral surface magnetized with a uniform strength, and the rotating armature rotates so that the teeth of the armature approach or separate from the permanent magnet piece. When it does, the magnetic flux density changes rapidly. For this reason,
The magnetic flux density with respect to the rotation angle of the armature changes stepwise, which causes noise and vibration of the DC motor.

Therefore, when the permanent magnet obtained by the conventional magnetizing device is used in the DC motor, the above-mentioned various problems occur.

The present invention has as its basic purpose to solve the above-mentioned problems, and an object thereof is to provide a magnetizing device capable of efficiently giving an appropriate magnetized state to a magnetic body.

[Means for Solving the Problems] In order to solve the above problems, a magnetizing device of the present invention has a magnetic body for a permanent magnet, which includes two facing surfaces and a plurality of side surfaces surrounding the periphery between the surfaces. A magnetizing magnetic pole of a magnetizing field part is arranged so as to face one of the surfaces of the magnetic body, and the magnetizing magnetic poles are arranged so as to respectively face two opposite side surfaces of the magnetic body. Two magnetic poles, a magnetized magnetic pole and a counter pole, are arranged, the magnetized magnetic pole and the counter pole are connected by a magnetic material, and further, on the other surface of the magnetic body,
A magnetization suppressing field portion is provided so as to face a magnetic pole having the same polarity as the magnetizing magnetic pole.

The shape of the magnetic body is not limited as long as it has two surfaces and a side surface.

The material of the magnetic body is not particularly limited as long as it is suitable for the permanent magnet.

The magnetizing field part facing the one surface of the magnetic body is generally composed of an electromagnet, but it is conceivable to use a permanent magnet.

Further, the counter pole magnetic pole facing the side surface of the magnetic body may be directly faced by the magnetizing field portion, or may be provided with a yoke.

Further, the other surface of the magnetic body faces the magnetic pole of the magnetization suppressing field portion having the same polarity as the magnetizing magnetic pole.

The magnetization suppressing field portion can be composed of an electromagnet or a permanent magnet, and the magnetization suppressing state, that is, the depth of the unmagnetized layer can be changed by selecting an appropriate magnetic field strength. You can

It is desirable that the magnetic poles are brought into close contact with the magnetic material, but the close contact is not essential for the present invention.

In addition, the magnetization suppressing field part is composed of a permanent magnet, and by changing the thickness of the permanent magnet in the suppressing direction, an appropriate magnetic distribution is given to the magnetic field strength of the permanent magnet, and the depth of the unmagnetized part is increased. It is also possible to adjust appropriately.

[Operation] That is, according to the present invention, a magnetic path is formed between the magnetized magnetic pole and one surface of the magnetic body, and between the counter magnetic pole of the magnetized magnetic pole and the side surface of the magnetic body, and passes through one of the magnetic paths. Magnetic flux is
It flows toward the other magnetic path, and the magnetic body is magnetized in accordance with this magnetic flux flow. Then, magnetic poles appear on the above-mentioned one surface of the magnetic body, and magnetic poles of different polarities appear on the side surfaces.

Further, since the magnetic pole of the magnetization suppressing field portion having the same polarity as the magnetizing magnetic pole is made to face the other surface of the magnetic body, the magnetic field lines of the magnetic field portion for magnetization and the magnetic field lines of the magnetic field suppressing portion are different from each other. Since they do not intersect, a non-magnetized layer (a layer with extremely small magnetization) with an appropriate depth can be formed on the other surface side of the magnetic material, and the desired magnetized state can be achieved without generating leakage flux from the other surface side. Is definitely obtained. The depth of the non-magnetized layer can be changed by changing the magnetic field strength of the magnetic field for suppressing magnetization based on the magnetic field strength of the magnetic field for magnetization.

[Embodiment] An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

An iron core 1 having a rectangular frame-shaped cross section is made of a material such as ferrite (iron oxide) having a low magnetic resistance, and a core portion 2 made of a cylinder or a prism is erected on a lower frame portion 1a of the iron core. At the tip of part 2, teeth 2a with a fan-shaped cross section
Is provided.

The iron core 1, the core portion 2, and the teeth 2a are formed by magnetically closely contacting the respective members, but it is also possible to integrally form the same material.

A field coil 3 is wound around the side surface of the core portion 2. The field coil 3 is connected to a DC power source (not shown), and an N pole is generated in the tooth 2a by energizing and exciting. It is as a configuration.

That is, the core portion 2, the teeth 2a, the field coil 3
The magnetizing field portion is constituted by, and the magnetizing magnetic pole is constituted by the teeth 2a.

Further, the horizontal frame 1 of the iron core 1 is provided on the upper surface of the tooth 2a.
A substantially rectangular parallelepiped magnetic body 4 for permanent magnets, which has a width equal to the distance between b and 1b and whose upper and lower surfaces are formed in an arc, is installed, and is the arc-shaped upper surface of the tooth 2a and one surface of the magnetic body 4. Both side surfaces of the magnetic body 4 are in contact with the arc-shaped lower surface 4a
4b is in contact with the inner surface 1d of the horizontal frame 1b, which is the counter magnetic pole of the tooth 2a.

For the magnetic body 4, it is desirable to use a material having a high residual magnetic flux density for a permanent magnet. For example, an Sm-Co based material is used.

Further, on the arc-shaped upper surface 4c of the magnetic body 4, a permanent magnet 5 forming a magnetization suppressing field portion is installed. This permanent magnet 5
The lower surface of is formed in an arc shape along the upper surface 4c of the magnetic body 4,
The upper surface of the permanent magnet 5 is formed as a flat surface along the inner surface of the upper frame 1c of the iron core 1.

Therefore, the magnetic body 4 includes the teeth 2, the horizontal frame 1b,
The permanent magnet 5 holds the four surfaces in close contact with each other.

The permanent magnet 5 is vertically magnetized and has an N pole on the lower surface and an S pole on the upper surface. Further, as described above, since the permanent magnet 5 has the thinnest central portion and the largest thickness at both ends, the magnetic field strength is minimum in the central portion.
It increases gradually as it moves to the side, and becomes maximum at both ends.

 The operation of this magnetizing device will be described below.

By energizing the field coil 3, the core portion 2 is magnetized, and an N pole is generated on the upper surface of the tooth 2a.

The magnetic flux generated from the upper surface of the tooth 2a flows into the inside from the lower surface 4a of the magnetic body 4. The magnetic flux gradually changes its direction to the side inside the magnetic body 4, and from both side surfaces 4b, 4b, the horizontal frame 1b
Flow to the inner surface 1d, descend in the horizontal frame 1b, from the lower frame 1a,
It flows into the lower part of the core part 2. At this time, an N pole having the same pole as that of the tooth 2 appears on the lower surface of the permanent magnet 5 to prevent the magnetic flux from the tooth 2a from flowing into the upper surface of the magnetic body 4 and An unmagnetized layer is formed on the upper surface side of No. 4.

As described above, the magnetic body 4 has a lower surface as shown in FIG.
An S pole appears on 4a and an N pole appears on both side surfaces 4b.

The central portion of the magnetic body 4 is deeply magnetized due to the distribution of the magnetic field strength of the permanent magnet 5 described above (lower surface side depth t1:
The upper surface depth t2 is 7: 3), while both ends of the magnetic body 4 are shallowly magnetized. As a result, the neutral line 6 of the magnetic pole has the maximum depth in the central portion, the depth gradually decreases as it moves away from the side, and reaches the lower surface of the magnetic body 4 before reaching the side end.

Therefore, on the lower surface of the magnetic body 4, the magnetic fluctuation at the end portion is small.

Also, unlike the above, it has an N pole on the lower surface and S on both sides.
When obtaining a permanent magnet having a pole, the S pole is made to appear on the tooth 2a, and the permanent magnet having the S pole is arranged on the upper surface of the magnetic body.

In the DC motor using the permanent magnets described above, since the outer peripheral surface of the permanent magnet is not used as a magnetic path, high accuracy is not required for the contact portion between the outer peripheral surface and the inner peripheral surface of the motor body (yoke), and grinding is performed. The process etc. can be omitted. Further, in the magnetic circuit, the bent portion of the motor main body having a relatively large magnetic resistance is also removed, and the effective magnetic flux is improved.

Further, the permanent magnet has the largest magnetic flux density in the central part in the circumferential direction, the magnetic flux density gradually decreases as it moves away from the side, and the magnetic fluctuation is minute at the side end part. The magnetic flux density does not fluctuate rapidly when approaching or separating from, and cogging, uneven rotation, vibration, etc. are reduced.

In this embodiment, the magnetizing device is configured by providing the core portion in the iron core having a rectangular frame shape in cross section.
It is not limited to this structure. That is, it suffices that the magnetized magnetic pole, the magnetic pole opposite to the magnetized magnetic pole, and the magnetic pole of the magnetization suppressing field portion face the predetermined surface of the magnetic body, and the magnetic poles and their coupled states are not limited.

Furthermore, in order to minimize the above-mentioned magnetic fluctuation, this permanent magnet has a thin central part and a large thickness on the side end side to minimize the magnetic field strength at the central part and maximize the magnetic field strength at the side end part. Is desirable.

[Effects of the Invention] As described above, according to the present invention, the magnetizing magnetic poles of the magnetizing field portion are arranged so as to face one of the surfaces of the magnetic body, and the magnetic poles are provided on two opposite side surfaces of the magnetic body. Two magnetic poles, the magnetized magnetic pole and the counter electrode, are arranged to face each other, the magnetized magnetic pole and the counter magnetic pole are connected by a magnetic material, and the magnetized magnetic pole and the magnetized magnetic pole are connected to the other surface of the magnetic body. Since the magnetic field for suppressing magnetization is provided to face the magnetic pole of the pole, the magnetic pole appears on one surface and the side surface, there is no leakage flux from the other surface side, and the permanent magnet having the desired magnetized state can be efficiently used. The permanent magnet can be obtained at low cost, and by using this permanent magnet for a DC motor, there is an effect that the manufacturing efficiency of the motor and the motor performance are improved.

[Brief description of drawings]

FIG. 1 is a front sectional view showing an embodiment of the present invention, and FIG.
FIG. 3 is a schematic view showing a magnetized state of the permanent magnet obtained by the embodiment, FIG. 3 is a front sectional view showing a conventional example, and FIG. 4 is a schematic view showing a magnetized state of the permanent magnet obtained by the conventional example. It is a figure. 1d ... Inner surface of horizontal frame, 2 ... Core portion 2a ... Teeth, 3 ... Field coil 4 ... Magnetic material, 4a ... Magnetic material lower surface 4b ... Magnetic material side surface, 5 ... Permanent magnet

Claims (1)

(57) [Scope of utility model registration request] 1. A device for magnetizing a magnetic body for a permanent magnet, which comprises two opposing surfaces and a plurality of side surfaces surrounding the periphery between the surfaces, the apparatus being provided on one of the surfaces of the magnetic body. To this end, the magnetizing magnetic poles of the magnetizing field portion are arranged, and the two magnetic poles of the magnetizing magnetic pole and the counter pole are arranged so as to respectively face the two opposite side surfaces of the magnetic body. The magnetic pole is connected with a magnetic material, and a magnetization suppressing field portion is provided on the other surface of the magnetic body so as to face a magnetic pole having the same polarity as the magnetizing magnetic pole. Magnetizing device