JP2001268860A - Multiple pole magnetizing method and magnetizer for magnet rotor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetizing method for improving a problematic shortage of magnetization due to narrowing of the pole pitch which accompanies the reduction in size of a magnet rotor, and a magnetizer for a magnet rotor. SOLUTION: By arranging a plurality of magnet pieces radially, a plurality of inversion magnetic poles are formed in their center part. By arranging a magnet rotor in the center part, magnetization in accordance with the number of the inversion magnetic poles is performed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-pole magnetizing method for a magnet rotor used in a motor or the like and a magnet rotor for the magnet rotor.

[0002]

2. Description of the Related Art As a method of multipolar magnetizing a magnet rotor used in a radial gap type motor or the like, a method using a dedicated magnetizer capable of generating a multipolar magnetic field in a radial direction, a method using a magnet divided in advance, or the like. There are known those in which segments are individually magnetized and assembled into a rotor. On the other hand, miniaturization of motor rotors has been remarkable in recent years, and those of milli-order size have also appeared, and it is thought that in the future it will progress to the size of sub-millimeter order. In such a magnetizing method, when such a small magnet rotor is magnetized, its small size makes handling and assembly difficult. For this reason, it is necessary to rely on the technique using the dedicated magnetizer. A typical dedicated magnetizer used in this method is, for example, a four-pole magnetizer shown in FIG. This dedicated magnetizer is composed of a coil 11 for generating a magnetic field in the radial direction and a yoke 12 of a soft magnetic material. Magnetization is performed at the center of the magnetizer by a rotor shaft 14a and a rotor magnet 14b. By setting the magnet rotor 14 having the above and energizing the coil 11, a magnetic field of a total of four poles is generated alternately in the radial direction with N poles and S poles.

[0003]

However, in this conventional dedicated magnetizer, a magnetic field is generated by flowing a current through the coil 11, so that the magnetic pole pitch can be reduced with the downsizing of the rotor, The coil pitch of the magnetizer must be reduced. For this reason, the wire diameter of the coil is inevitably reduced, but the upper limit value of the current density that can be passed through the coil 11 is substantially determined by the coil fusing value (for example, when a coil having a wire diameter of Φ0.5 mm is used). In the case of applying a pulse current having a half width of 10 msec, the upper limit was about 4000 A / mm ² ). If the outer diameter of the magnet rotor 14 is reduced to 1 / K by reducing the size of the magnet rotor 14, the current value that can flow under the constraint of the constant current density is proportional to the conductive wire cross-sectional area of the coil 11 by (1/1 / K) ²
As a result, the magnetic field is 1 / K times as large as before. Therefore, as the size of the magnet rotor 14 is reduced, the amount of magnetic field that can be generated decreases, and a rotor having an outer diameter of 1 mm or less has a problem of insufficient magnetization magnetic field.

The present invention has been made by paying attention to such problems existing in the conventional technology. An object of the present invention is to provide a magnetizing method and a magnetizer for improving insufficient magnetization, which is a problem when the pitch of magnetic poles is reduced due to downsizing of a magnet rotor.

[0005]

In order to achieve the above object, in the magnetizing method according to the present invention, a plurality of magnet pieces are radially arranged to form a plurality of reversal magnetic poles at the center thereof, and the center of the magnet is formed. It is characterized in that four or more poles are magnetized by arranging a magnet rotor in the portion.

Further, in the magnetizer according to the present invention, the insertion hole of the magnet rotor to be magnetized formed at the center and the periphery of the insertion hole such that a plurality of reversal magnetic poles are formed at the center. And a plurality of magnetic pole-side magnet pieces radially arranged in a radial direction, and a frame made of a non-magnetic material for supporting these magnetic pole-side magnet pieces.

According to the magnetizing method and the magnetizer of the present invention, the magnet is used as the magnetizing magnetic field generating means.
There is no limitation on the current density in the related art, and the problem of a decrease in the amount of generated magnetic field due to miniaturization does not fundamentally occur.

Further, in the magnetizer according to the present invention, the insertion hole of the magnet rotor to be magnetized formed in the center and the periphery of the insertion hole such that a plurality of reversal magnetic poles are formed in the center. And a plurality of magnetic pole-side magnet pieces radially arranged on the magnetic pole, and an outer yoke made of a soft magnetic material also serving as a frame supporting the magnetic pole-side magnet pieces. In such a configuration, since the magnet is used as the magnetizing magnetic field generating means, there is no limitation on the current density in the related art, and the problem of the decrease in the amount of magnetic field generated by miniaturization does not fundamentally occur. In addition, the outer peripheral magnet piece described above can be omitted.

Further, the magnetic pole side and the outer peripheral side magnet pieces in the magnetizer are preferably Nd-FE-B-based magnets. In this case, the Nd-Fe-B-based magnet has a high energy product. A high magnetic field can be generated, and the magnetization strength of the rotor can be increased.

Further, the magnetizer according to the present invention may be provided with a magnetic pole yoke made of a soft magnetic material on the side of the insertion hole of the magnetic pole side magnet piece. The function can increase the magnetizing strength of the rotor.

The magnetic pole yoke in the magnetizer is preferably made of an iron-cobalt alloy. In this case, the magnetic flux can be concentrated on the magnetic pole portion because of the high magnetic conductivity of the iron-cobalt alloy. Can be further increased.

[0012]

Embodiments of the present invention will be described below in detail. Embodiment 1 FIG. FIG. 1 is a schematic diagram of a four-pole magnetizer according to the first embodiment. The four magnetic pole-side magnet pieces 2 are radially changed and the directions of magnetization are alternately changed so as to form an insertion hole 1 for installing the magnet rotor 4 to be magnetized in the center of the frame 7. N poles and S poles are formed alternately. In addition, on the outer periphery, a magnetic loop is formed so as to form a magnetization loop in cooperation with the magnetization directions of the four magnetic pole side magnet pieces.
The outer peripheral magnet pieces 3 are provided. Reference numeral 7 denotes a frame for supporting the magnet pieces 2 and 3, and reference numeral 8 denotes a space formed between adjacent magnetic pole side magnet pieces 2 arranged radially.

After the magnet pieces 2 and 3 are fully unidirectionally magnetized in an anisotropic direction by a separate large magnetizer, the magnet pieces 2 and 3 are placed inside the frame 7 as described above (that is, in the direction of magnetization shown in FIG. 1). ) Is interpolated and secured with epoxy adhesive.

In the magnetizer of the first embodiment, a strong multi-pole magnetic field is formed at the center by the assembly of the magnet pieces 2 and 3 with the above configuration. Therefore, when the magnet rotor 4 is magnetized by this magnetizer, the rotor shaft 4
By inserting the magnet rotator 4 provided with a and the magnet 4b into the insertion hole 1 for a predetermined time, the magnet rotator 4 is magnetized in four poles.

Next, a description will be given of an evaluation result of an experiment conducted on a sample magnetizer for the amount of magnetization by the magnetizer of the first embodiment. The sample magnetizer uses Sm-Co magnets equivalent to a maximum energy product of 30 MGOe as the magnetic pole side magnet piece 2 and the outer peripheral side magnet piece 3, and separates each magnet piece 2, 3 in an anisotropic direction by a separate large magnetizer. After the magnet was fully magnetized in the direction, it was inserted and arranged inside the aluminum frame 7 as described above and fixed with an epoxy adhesive. The inner diameter of the insertion hole 1 is 1.08 mm, 0.88 mm, 0.6
We prepare three types of 8mm, each with an outer diameter of 1.0mm,
A quadrupole magnetization experiment was performed on the 0.8 mm and 0.6 mm magnet rotors 4. Also, the rotor magnet 4b of the magnet rotor 4
A Nd—Fe—B-based radial anisotropic ring magnet (thickness: 0.1 mm, length: 1 mm) was used. Magnetization by the sample magnetizer was performed by inserting the magnet rotor 4 into the insertion hole 1 at the center of the magnetizer, leaving it for a few seconds, and then pulling it out.

For comparison with this sample device, a conventional magnetizer having a coil 11 and a yoke 12 (see FIG. 6) was experimentally manufactured, and a quadrupole magnetizing experiment was similarly performed. The inner diameter of the rotor insertion hole of the conventional magnetizer is 1.08 m.
Three types of m, 0.88 mm, and 0.68 mm were prepared, and four-pole magnetization was performed on the magnet rotor 4 of 1.0 mm, 0.8 mm, and 0.6 mm, respectively. In this case, the diameter of the coil wire is. They were 5 mm, 0.4 mm, and 0.3 mm. Also, the magnetization is a peak value of 7 with a half width of 10 msec.
A pulse current of 80, 500, and 280 A (all allowable maximum current values at each wire diameter) was applied.

The amount of magnetization of the magnet rotor 4 configured as described above and magnetized is set to 10000 r using a jig.
The rotor was rotated at pm, and the magnetic flux generated from the magnet rotor 4 was detected in the form of an induced voltage by a pickup coil using a motor stator, and the amount of magnetization was evaluated based on this.
Table 1 shows the measurement results. Regardless of the size of the magnet rotor 4 magnetized according to the present embodiment, the output voltage of the pickup coil is higher and the magnetization amount is higher than that of a rotor magnetized by a conventional magnetizer, regardless of the size. You can see that. In addition, the smaller the size of the magnet rotors 4 and 14, the larger the difference between them. Therefore, it can be said that the magnetizer of the present invention has higher magnetization performance with respect to a smaller magnet rotor.

[0018]

[Table 1]

Embodiment 2 Next, a second embodiment will be described with reference to FIG. The second embodiment differs from the first embodiment in the shapes of the frame 7, the magnetic pole side magnet piece 2 and the outer peripheral side magnet piece 3, and has two magnetic pole side magnet pieces 2 as a set. And a magnetic pole yoke 5 made of a soft magnetic material is provided on the insertion hole side of the magnetic pole side magnet piece 2. The pair of magnetic pole-side magnet pieces 2 located outside the magnetic pole yoke 5 are set so that their magnetization directions are concentrated at the center of the magnetic pole yoke 5 to increase the concentration of magnetic flux.

After the magnet pieces 2 and 3 are fully magnetized in one direction in an anisotropic direction by a separate large magnetizer, they are inserted into the frame 7 together with the magnetic pole yoke 5 in the direction of magnetization shown in FIG. It is placed and fixed with epoxy adhesive.

In the magnetizer according to the second embodiment, a strong multipolar magnetic field is formed at the center by the assembly of the magnet pieces 2 and 3 and the magnetic pole yoke 5 by the structure described above. By inserting the magnet rotor 4 having the magnet 4a and the magnet 4b into the insertion hole 1 for a predetermined time, the magnet rotor 4
It can be poled.

Next, a description will be given of an evaluation result of an experiment conducted on a sample magnetizer for the amount of magnetization by the magnetizer of the second embodiment. In the sample magnetizer, after each magnet piece 2, 3 is unidirectionally fully magnetized in the anisotropic direction by a separate large magnetizer,
By inserting and arranging inside the bakelite frame 7 as described above and fixing with epoxy adhesive, 4
A pole magnetizer was manufactured. In addition, as the magnetic pole side magnet pieces 2 and 3, an Sm-Co magnet (equivalent to 30 MGOe) and Nd-Fe
-B magnet (equivalent to 42MGOe) is manufactured,
The magnetic pole yoke 5 was manufactured using iron and an Fe—Co alloy. The inner diameter of the insertion hole 1 was 0.68 mm, and a four-pole magnetization experiment was performed on the magnet rotor 4 having an outer diameter of 0.6 mm. As the rotor magnet 4b of the magnet rotor 4, an Nd—Fe—B-based radial anisotropic ring magnet (thickness: 0.1 mm, length: 1 mm) was used. Magnetization by the sample magnetizer configured as described above was performed by inserting the magnet rotor 4 into the insertion hole 1 at the center of the magnetizer, leaving it for a few seconds, and then pulling it out.

The amount of magnetization of the magnet rotor 4 configured as described above and magnetized is set to 10000 r using a jig.
The rotor was rotated at pm, and the magnetic flux generated from the magnet rotor 4 was detected in the form of an induced voltage by a pickup coil using a motor stator, and the amount of magnetization was evaluated based on this. Table 2
Shows the measurement results. In the table, for comparison,
Also shown are the measurement results for the magnet rotor having an outer diameter of 0.6 mm in the first embodiment.

[0024]

[Table 2]

According to the result, the present embodiment 2 (A)
Shows the measurement results in the case where iron is used as the magnetic pole yoke 5. Since the output voltage is increased by 10% or more compared to Embodiment 1 having no magnetic pole yoke 5, the function of concentrating the magnetic flux is performed. It can be seen that the magnetic pole yoke 5 is effective for increasing the amount of magnetization. Embodiment 2 (a)
The measurement results in the case of using Nd—Fe—B magnets as the magnet pieces 2 and 3 are shown. The output voltage is further higher than that of Embodiment 2 (A) in which the magnet pieces 2 and 3 are Sm—Co. Is increased by about 10%, so that N having a high energy product
It can be seen that the d-Fe-B magnet is effective for increasing the amount of magnetization. Further, the second embodiment (c) shows the measurement results when an Fe—Co alloy is used as the magnetic pole yoke 5, and the second embodiment (a) in which the magnetic pole yoke 5 is iron.
On the other hand, an increase in output voltage was further confirmed, and it was confirmed that an Fe—Co alloy having high magnetic conductivity due to high saturation magnetization was effective in increasing the amount of magnetization.

Embodiment 3 FIG. Next, a third embodiment will be described with reference to FIG. The third embodiment differs from the first embodiment in that the shape of the magnetic pole-side magnet pieces 2 is different, that the magnetic pole-side magnet pieces 2 are paired, and that the magnetic pole-side magnet pieces 2 The difference is that a magnetic pole yoke 5 is provided on the insertion hole side, and that an outer yoke 6 made of a soft magnetic material serving as a frame is provided instead of the frame 7 by omitting the outer magnet piece 3. The pair of magnetic pole-side magnet pieces 2 located outside the magnetic pole yoke 5 are set so that their magnetization directions are concentrated at the center of the magnetic pole yoke 5 to increase the concentration of magnetic flux.

The magnetic pole side magnet piece 2 is fully magnetized in one direction in an anisotropic direction by a separate large magnetizer.
3 is interposed with the magnetic pole yoke 5 in the direction of magnetization shown in FIG. 3 and fixed with an epoxy adhesive.

The magnetizer according to the third embodiment is configured as described above, and thus, the assembly of the magnet pieces 2 and the magnetic pole yoke 5
A strong multi-pole magnetic field is formed at the center by the outer yoke 6 and the magnet rotor 4 having the rotor shaft 4a and the magnet 4b is inserted into the insertion hole 1 for a predetermined period of time. Are magnetized in four poles.

The outer yoke 6 serves as a substitute for the outer magnet piece 3 in the first embodiment. Since the outer yoke 6 is made of a soft magnetic material, the outer yoke 6 naturally forms a magnetization loop based on the magnetization direction of the magnetic pole piece 2. Form. Therefore, the number of magnet pieces can be reduced by the outer yoke 6, and the outer yoke 6 also serves as a frame, so that the configuration of the magnetizer can be simplified and the cost can be reduced.

Next, a description will be given of an evaluation result of an experiment conducted on a sample magnetizer for the amount of magnetization by the magnetizer of the third embodiment. The sample magnetizer uses N as the magnetic pole side magnet piece 2.
Using a d-Fe-B magnet (equivalent to 42 MGOe), the magnet piece 2 is unidirectionally fully magnetized in an anisotropic direction by a separate large magnetizer, and then the magnetic pole yoke 5 is placed inside the outer yoke 6 made of iron.
3 and interposed and arranged as shown in FIG. 3, and these were fixed with an epoxy adhesive to produce a four-pole magnetized device. Note that an Fe—Co alloy was used as the magnetic pole yoke 5. The inner diameter of the insertion hole 1 was 0.68 mm, and a four-pole magnetization experiment was performed on the magnet rotor 4 having an outer diameter of 0.6 mm. The rotor magnet 4b of the magnet rotor 4 is N
d-Fe-B based radial anisotropic ring magnet (thickness:
0.1 mm, length: 1 mm). Magnetization by the sample magnetizer configured as described above was performed by inserting the magnet rotor 4 into the insertion hole 1 at the center of the magnetizer, leaving it for a few seconds, and then pulling it out.

For comparison with the present sampler, FIG.
As a conventional example described above, a coil wire having a diameter of 0.3 mm was manufactured, and a peak value of 280 A was obtained at a half width of 10 msec.
A 4-pole magnetization was performed on the magnet rotor 4 having an outer diameter of 0.6 mm by applying a pulse current of (permissible maximum current value at the same wire diameter).

The amount of magnetization of the magnet rotor 4 configured as described above and magnetized is set to 10000 r using a jig.
The rotor was rotated at pm, and the magnetic flux generated from the magnet rotor 4 was detected in the form of an induced voltage by a pickup coil using a motor stator, and the amount of magnetization was evaluated based on this. Table 3
Shows the measurement results.

[0033]

[Table 3]

According to the results, it was confirmed that the output voltage of the pickup coil was higher and the magnetization amount was higher in the present embodiment than in the conventional example.

Embodiment 4 FIG. In each of the above embodiments, the case of four-pole magnetization has been described as a specific example. However, with regard to a greater number of magnetic poles, a desired reversal magnetic pole is provided at the center by arranging corresponding magnet pieces radially. Can be formed to form a magnetized device. In the present embodiment, 8
This is an example of a pole magnetizer, which is shown in FIG. here,
Without attaching a magnetic pole yoke, the direction of magnetization was
The magnetic pole side magnet pieces 2 are arranged radially, and an outer yoke 6 is provided on the outside to constitute a magnetizer. By inserting a magnet rotor 4 having a rotor shaft 4a and a rotor magnet 4b into a central portion of the magnetizer for a predetermined time, 8-pole magnetization can be performed.

The present invention is not limited to the above embodiments, but can be embodied as follows. (1) In each of the above embodiments, the magnetic pole side magnet piece 2,
The shapes of the outer magnet piece 3, the magnetic pole yoke 5, and the frame 7 are as follows.
It is not limited to the above example. For example, regarding the first embodiment, a shape as shown in FIG. 4 may be used. In the figure, the same parts as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

(2) In each embodiment, a space 8 is formed between the magnetic pole side magnet pieces 2 arranged radially and between the adjacent magnetic pole side magnet pieces 2. 8 may be filled with a non-magnetic material to improve the fixing strength of the magnet pieces 2 and 3. Also, in order to facilitate the work of assembling the magnet pieces 2 and 3, the magnet piece assembling member is fixed in advance to the space 8, and then the magnet pieces 2 and 3 are inserted and fixed. You may go. Note that the use of a ferromagnetic material in the cavity 8 affects the strength of the magnetizing magnetic field, and therefore, it is preferable to avoid using it. For the same reason, it is preferable to use a nonmagnetic material instead of the ferromagnetic material for the frame 7.

[0038]

Since the present invention is configured as described above, it has the following effects. According to the invention as set forth in claims 1 to 7, a plurality of magnetic pole side magnet pieces are radially arranged, a plurality of reversing magnetic poles are formed at the center thereof, and a magnet rotor is arranged at the center. Since the present invention is characterized in that magnetization of four or more poles is performed, there is no limitation on the coil current density, which has conventionally been a problem, and the problem of a decrease in the amount of magnetic field generated due to miniaturization is basically solved. For this reason, the outer diameter is 1 mm
A high amount of magnetization can be given to the following small-sized magnet rotors.

According to the third or fifth aspect of the present invention, the magnetic pole side magnet piece and the outer peripheral side magnet piece are formed, or the magnetic pole side magnet piece is formed of an Nd-Fe-B based magnet piece. Has a high energy product, a high magnetic field can be generated, and the magnetizing strength of the rotor can be increased.

According to the fourth aspect of the present invention, since the outer yoke also serves as the frame and the outer peripheral magnet piece, the configuration of the magnetizer can be simplified and the cost can be reduced.

According to the sixth aspect of the present invention, since the magnetic pole yoke is provided on the insertion hole side of the magnetic pole side magnet piece, the magnetizing strength of the rotor can be further increased by the magnetic flux concentration function of the magnetic pole yoke. Can be.

According to the seventh aspect of the present invention, since the magnetic pole yoke is made of an iron-cobalt alloy, the magnetic flux can be concentrated on the magnetic pole portion due to the high magnetic conductivity of the alloy.
The magnetizing strength of the rotor can be further increased.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view for explaining a magnet rotor magnetizer according to Embodiment 1 of the present invention.

FIG. 2 is a cross-sectional view illustrating a magnet rotor magnetizer according to a second embodiment of the present invention.

FIG. 3 is a cross-sectional view for explaining a magnet rotor magnetizer according to a third embodiment of the present invention.

FIG. 4 is a cross-sectional view for explaining a magnet rotor magnetizer according to a fourth embodiment of the present invention.

FIG. 5 is a cross-sectional view of a magnet rotor magnetizer according to a modification of the first embodiment.

FIG. 6 is a cross-sectional view for explaining a conventional typical magnet rotor magnetizer.

[Explanation of symbols]

1 coil, 2 magnetic pole side magnet pieces, 3 outer peripheral side magnet pieces, 4
Magnet rotor, 4a rotor shaft, 4b rotor magnet, 5
Magnetic pole yoke, 6 outer yokes, 7 frames, 8 voids.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Toshio Umemura 2-3-2 Marunouchi, Chiyoda-ku, Tokyo F-term (reference) 5H002 AA09 AC06 5H622 CA02 CA05 CA13 DD02 PP19 QB01 QB09

Claims (7)

[Claims] 1. A method in which a plurality of magnet pieces are radially arranged to form a plurality of reversing magnetic poles at the center thereof, and a magnet rotor is arranged at the center to magnetize four or more poles. Characteristic multi-pole magnetizing method for magnet rotor. 2. An insertion hole formed in a center portion of a magnet rotor to be magnetized, and radially arranged around the insertion hole so that a plurality of reversal magnetic poles are formed in the center portion. A plurality of magnetic pole side magnet pieces, an outer circumferential side magnet piece arranged so as to form a magnetic loop in cooperation with the magnetization direction of the plurality of magnetic pole side magnet pieces, and these magnetic pole side magnet pieces and the outer circumferential side magnet piece A magnet made of a non-magnetic material to be supported. 3. The magnet rotor according to claim 2, wherein the magnetic pole side magnet piece and the outer peripheral side magnet piece are Nd—Fe—B based magnets. 4. An insertion hole formed in a center portion of a magnet rotor to be magnetized, and a plurality of radially arranged around the insertion hole such that a plurality of reversal magnetic poles are formed in the center portion. And a magnetic yoke made of a soft magnetic material also serving as a frame for supporting these magnetic pole side magnet pieces. 5. The magnet rotor according to claim 4, wherein the magnetic pole-side magnet piece is an Nd—Fe—B-based magnet. 6. The magnetic rotor garment according to claim 2, wherein a magnetic pole yoke made of a soft material is provided on the insertion hole side of each of the magnetic pole side magnet pieces. porcelain. 7. The magnet rotor according to claim 6, wherein the magnetic pole yoke is made of an iron-cobalt alloy.