JP2000012317A - Magnet and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To well magnetize a thinned magnet without giving any damage to the magnet by using soft paint having pencil hardness of a specific value or smaller as the coating material of the magnet and, at the same time, adjusting the film thickness of the coating material to a specific value of smaller. SOLUTION: Each thin base magnet material piece having a specific size is obtained by slicing an ingot of a sintered base magnet material composed of a sintered rare-earth metallic material of Nd, Sm-Co, Alnico, etc. Then the corner sections of the end faces of each magnet blank are shaped to round corners of about 0.1 mm or more in radius and each sintered magnet blank 25 thus obtained is subjected to surface roughening as surface treatment. After surface treatment, the magnet blank 25 is put in a container 1 and the container 1 is rotated at a prescribed rotating speed. Then, while a hot blast is blown into the container 1, the hot blast is always sucked by operating an included draft blower 24. Thereafter, soft paint 23 having pencil hardness of <=3 H is sprayed upon the magnet blank 25 on the bottom of the contained 1 from a spray nozzle 2a. The film thickness of the paint 23 is set at about >=15 μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnet having a surface coated with a rust preventive or the like, and a method for manufacturing the same.

[0002]

2. Description of the Related Art Generally, in manufacturing a magnet,
A magnet material is formed in a predetermined shape, and the magnet material is mounted so as to face a head portion of the magnetizing device via a predetermined gap. To magnetize the magnet material. The gap between the magnetizing head and the magnet material at this time is set to a very small amount (for example, about 0.1 mm) in order to improve the magnetic characteristics.

[0003]

However, magnets in recent years tend to be thinner and smaller. If such thinner and smaller magnet materials are magnetized with a small gap, the magnets may be magnetized. At the time of magnetizing, the magnetic attraction between the magnetized head and the magnet causes the two to collide with each other, and the magnet is frequently damaged or broken or chipped. The collision between the magnetized head and the magnet is called a hammer effect, but is caused by bending of the support member on the magnetized head even when the magnet is fixed in an immobile state. It is. In particular, a sintered magnet using a rare earth metal such as Nd is susceptible to damage due to impact due to its brittle nature.

Accordingly, an object of the present invention is to provide a magnet and a method for manufacturing the same, which are capable of satisfactorily magnetizing a thinned magnet without causing damage such as cracking or chipping. It was done.

[0005]

According to the first aspect of the present invention, there is provided a magnet in which a predetermined coating material is applied in the form of a film on a surface of a magnet material and magnetized.
The coating material is made of a soft paint having a pencil hardness of 3H or less, and the thickness of the soft paint is set to 15 μm or more.

Further, according to the invention described in claim 2, according to claim 1,
After applying a predetermined coating material in the form of a film on the surface of the described magnet material, in a method for manufacturing a magnet to perform magnetization,
A soft paint having a pencil hardness of 3H or less is used as the coating material, and the soft paint is applied so that the film thickness of the soft paint is 15 μm or more.

Further, in the invention according to the third aspect, before applying the soft material according to the second aspect, a base treatment step for increasing the adhesion of the soft material to the surface of the magnet material is performed. It is.

Furthermore, in the invention according to claim 4, the undercoating step according to claim 3 includes a step of applying an epoxy resin paint or a surface roughening step of roughening the surface of the magnet material.

According to a fifth aspect of the present invention, a fluorine-containing paint having an antirust effect is used as the soft paint according to the second aspect. A method for manufacturing a magnet, comprising:

Further, according to the invention described in claim 6, according to claim 2,
As the magnet material described, any one of Nd-based, Sm-Co-based, and alnico-based rare earth sintered metal materials is used.

Further, in the invention according to claim 7, a curved chamfer having a radius of 0.1 mm or more is formed at the corner of the end face of the magnet material according to claim 2.

According to the invention described in each of the claims, the impact caused by the collision between the head portion and the magnet at the time of magnetization is absorbed by the coating material made of a soft paint, and damages such as cracks and chips are avoided. Then, in order to reduce the frequency of occurrence of damage such as cracks and chipping to within a range that can be manufactured, the pencil hardness and film thickness of the soft paint are 3H or less and 15 μm or less.
m was found to be necessary.

[0013]

Embodiments of the present invention will be described below in the order of manufacturing steps. First, as a magnet material, Nd system,
A rare earth sintered metal material such as an Sm-Co type or an alnico type is used, and each magnet material is cut out from an ingot of the sintered magnet material by slicing into a thin plate having a predetermined size. Next, the cutting oil, wax and the like adhering to the surface of the sliced sintered magnet material are washed and removed with a solvent such as water or IPA while using ultrasonic waves.

Next, curved chamfering (hereinafter referred to as R chamfering) is performed on a corner portion of the end surface of the sintered magnet material as the sliced body using a roller barrel or the like. In the curved chamfering step using a roller barrel, abrasive stones such as alumina are simultaneously charged into the barrel at the same time as the sintered magnet material, and are mixed with each other.
Barrel processing is performed by a dry or wet method over a period of minutes, but in this embodiment, the radius of the chamfered portion is set to 0.1 mm or more, so that the coating on the corner portion of the end surface of the sintered magnet material described later is performed uniformly. Like that.

Subsequently, the sintered magnet material as the sliced body is subjected to drive blast or wet blast treatment as a base treatment to remove the smut on the roller barrel surface and roughen the surface of the sintered magnet material by roughening. Become After the wet blast treatment, ultrasonic cleaning is performed using water or a solvent (such as IPA) in order to remove fine processing powder. Note that the undercoating treatment at this time may be a step of applying an epoxy resin-based paint.

A sintered magnet material as a sliced body that has been subjected to the R chamfering and the surface roughening process as a base treatment as described above is weighed in a prescribed amount, and is charged into a barrel device, and a predetermined coating material is obtained. Apply a rust preventive material consisting of This barrel device is configured as, for example, a rust preventive material coating device as shown in FIG. 1, and includes a storage container 1 that rotates around a horizontal axis, and a nozzle 2 a at the center of the storage container 1. A spray means 2 installed to blow out the rust preventive material, a casing 5 rotatably supporting the storage container 1 and provided with a hot air supply means 3 and an exhaust means 4;
It comprises a motor 6 for rotating the storage container 1 and an inverter control unit 7.

The storage container 1 has a structure in which a barrel is placed horizontally, and has a wall surface 1a parallel to a horizontal rotation axis.
And inclined wall surfaces 1b and 1c, and a wall surface 1d orthogonal to the rotation axis. The wall surfaces 1a and 1b are made of a structure or a material through which hot air can pass. For example, in the case of the present embodiment, the wall surfaces 1a and 1b are formed of a wire mesh. However, the present invention is not particularly limited to this wire mesh, and a plate (porous slope) having a large number of slits and holes or a porous material may be used. It is also possible to form with a material.

An air-impermeable shell 8 is provided around the air-permeable wall surfaces 1a and 1b. The air-permeable wall surfaces 1a and 1b are covered with the shell 8 and exhaust means is provided outside the air-permeable wall surface. An exhaust chamber 12 communicating with the exhaust chamber 4 is formed. Inside the storage container 1, a net 10 made of Teflon (tetrafluoroethylene) or silicon is stretched from both side walls 1b and 1c to the parallel wall 1a. This net made of Teflon or silicon fiber
A mesh of 10 to 200 mesh, preferably about 30 mesh is employed.

Further, the container 1 is fixed to the shaft 13 of the drive motor 6 having the orthogonal wall 1d side supported by the bearing member 11, and the inlet 1e side is mounted on the bearing member 14 of the casing 5 to be rotatable. It is supported by. At the entrance 1e side of the storage container 1, a duct 1
5 are charged. On the other hand, the storage container 1 is provided with an exhaust unit 4 through an exhaust chamber 12 outside the permeable wall surfaces 1a and 1b.
Is connected to the duct 16.

The hot air supply means 3 comprises a heater 17, a duct 15, and a temperature sensor 18. The hot air obtained by the heating of the heater 17 of the hot air supply means 3 receives the hot air from the storage container 1 through the duct 15. It is configured to be supplied into. The temperature of the hot air to be supplied is automatically controlled based on the ambient temperature of the storage container 1 measured by the temperature detecting means 18. For example, a thermocouple-type temperature adjusting means is used as the temperature detecting means 18, and the output of the external heater 17 is controlled. by this,
A hot air of a predetermined temperature, for example, from room temperature to about 100 ° C. is supplied. The temperature of the hot air is appropriately determined depending on the rust preventive used, the use environment, the processing amount, and the like.

The spray hand throw 2 has a spray nozzle 2a inserted into the storage container 1 and installed substantially at the center, and an air supply pipe 19 for supplying spray air to the nozzle 2a.
And a rust preventive material supply pipe 20 for supplying a rust preventive material 23 to the spray nozzle 2a, a metering pump 21 for supplying a certain amount of the rust preventive material 23, and a paint tank 22 containing the rust preventive material 23. As the rust preventive in the present embodiment, a soft paint having a pencil hardness of 3H or less, for example, oflon 1819 made of a fluorine-containing paint having a rust preventive action.
(Manufactured by Ohashi Chemical Co., Ltd.), which is weighed in a specified amount and stored in the paint tank 22. In addition, the pencil hardness refers to the surface hardness obtained by drawing on the surface using a pencil having a different hardness,
It is represented by the hardness symbol of the pencil used. Paint tank 22
The rust preventive material 23 is supplied to the spray nozzle 2a by a required amount by the metering pump 21.

Although not shown, the air supply pipe 19 is connected to a pressure air supply source such as an air compressor. The exhaust hand throw 4 includes an exhaust duct 16 and an induction blower 24. The exhaust duct 16
In the case of this embodiment, by connecting to the exhaust unit 12 at the bottom of the storage container 1 in which the magnet 25 is stored, hot air is passed between as many sintered magnet materials 25 as possible and then exhausted. However, it is not particularly limited to this, as long as efficient ventilation can be achieved,
The connection position of the exhaust duct 16 is not particularly limited to the above-described position. Here, the efficient ventilation means that the hot air supplied from the inlet 1e stays to some extent in the storage container 1 and contacts the sintered magnet material 25 as much as possible. In addition, the contract container 1 is rotated by an external motor 6, and the number of rotations is provided so as to be appropriately adjustable by an inverter 7.

With the above-configured barrel device, a large amount of sintered magnet material 25 is uniformly coated with a rust preventive material as follows. First, an appropriate number, for example, 2,000 to 5,000, of the sintered magnet material 25 as a thin plate-shaped sliced body obtained as described above is charged into the storage container 1, and the rotation speed is 5 to 50 rpm. Rotate with. Then, while the hot air (normal temperature to 100 ° C.) is sent into the storage container 1, the induction blower 24 is moved and constantly discharged.

Then, the above-mentioned rust preventive material 23 is sprayed from the spray nozzle 2a toward the sintered magnet material 25 at the bottom of the storage container 1. The air pressure at this time is 1kg / cm
^2-3 kg / cm ² is appropriate. Since the thickness of the film to be coated greatly depends on the air pressure, the pressure is appropriately set according to the application and the like. In the present embodiment, the thickness of the rust preventive material is set to be 15 μm or more, and the supply amount is adjusted correspondingly to a range of 2 ml / min to 20 ml / min by the metering pump. .

The spray magnet material 25 is rolled on the Teflon or silicon net 10 by the rotation of the reduction container 1, or is lifted up, falls naturally, is constantly stirred, and is continuously stirred, and a spray gun for spraying the rust preventive material 23. The surface is constantly changed with respect to 2a so that the rust preventive 23 is sprayed uniformly on all surfaces. Moreover, since the hot air having a predetermined temperature suitable for coating with the rust-preventive material 3 passes through the periphery of the magnet 25, the anti-complex material 23 sprayed on the surface of the sintered magnet material 25 is immediately dried and adjoined. Other sintered magnet material 2
5 to form a film without bonding.

More specifically, the above-mentioned coating step is performed separately in a first coating step and a second coating step. In the first coating step, the above-mentioned Offlon 181 having a pencil hardness of 3H or less is used.
After coating 9 (manufactured by Ohashi Chemical Co., Ltd.) to a film thickness of 5 to 7 μm, a curing treatment is performed in an atmosphere at 200 ° C. for 30 minutes. In the second painting process,
9 (manufactured by Ohashi Chemical Co., Ltd.) by coating to a film thickness of 7 to 9 μm, and similarly in an atmosphere of 200 ° C. for 30 minutes.
Perform the curing process for a minute. The coating at this time is not limited to the one using the barrel coating device as described above, and various coating means such as spray coating can be adopted.

The coating layer of the rust preventive material 23 actually coated on the surface of the sintered magnet material 25 in this manner has a thickness of 15 μm.
m and a uniform thickness of ± 3 μm
Could be kept within. Further, a magnet having excellent corrosion resistance was obtained without a phenomenon in which the magnets were bonded to each other during coating.

When the sintered magnet material 25 that has been subjected to such anti-rust coating is magnetized by a magnetizing device, the impact caused by the collision between the magnetized head and the magnet is reduced by a coating material made of a soft paint. As a result, the material is absorbed by the rust preventive material 23, and damages such as cracks and chips are avoided. Then, in order to reduce the frequency of occurrence of damages such as cracks and chips to within a range that can be manufactured, it is necessary that the pencil hardness and the film thickness of the rust preventive material 23 as a soft paint be 3H or less and 15 μm or more. It turned out as follows.

That is, when the sintered magnet material 25 was magnetized at a magnetizing voltage of 1400 V, as shown in FIG. The relationship between the pencil hardness (horizontal axis) and the film thickness (vertical axis) of the rust preventive 23 was obtained. For example, pencil hardness is 3H
No cracking or chipping occurred in the case where Oflon 1819, which is a soft material, was coated to a film thickness of 16 μm (both cracking and chipping out of 100 pieces). Also, Oflon 18
In addition to 19, 3H Oflon SK-2 with the same pencil hardness
Was coated to a film thickness of 15 μm, and the hardness of the coating film was the same. Therefore, no cracking or chipping occurred during magnetization in this case (both cracking and chipping: 0 out of 100).

On the other hand, even when the same Offlon 1819 is coated, the film thickness may be 10.3 μm or
When the thickness was 8 μm, cracking and chipping occurred.
In the case of 5.8 μm, which occurred one by one, two out of twelve cracks and three out of twelve cracks occurred). Thus, the rust preventive material 23 made of a soft material having a pencil hardness of 3H.
In the case of using, it was found that it was necessary to apply the coating so that the film thickness became 15 μm or more. Further, with a softer rust preventive having a pencil hardness of about 2H, the film thickness is 10 μm.
If the pencil hardness is as high as about 4H, the film thickness is considered to be required to be 30 μm or more. However, it cannot be adopted because the actual production is difficult.

When a hard material is applied to the base of the rust preventive material 23 made of a soft paint, it is necessary to consider the difference by the thickness of the hard base treatment layer. For example, Ofron SK-2 (manufactured by Ohashi Chemical Co., Ltd.) having a pencil hardness of 3H after a base treatment by chromate treatment after aluminum deposition)
When 10 μm was applied, the occurrence of chipping was still observed (the number of cracks was 0 out of 20, but the chipping was 2).
It occurred in 5 out of 0).

Further, a paint film having a pencil hardness of 6H was applied as a base treatment to a film thickness of 10 μm as a base treatment, and an OFRON SK-2 (manufactured by Ohashi Chemical Co., Ltd.) having a pencil hardness of 3H was further applied thereon. In the case where a coating film having a total thickness of 20 μm was formed by applying 10 μm, cracks and chips were slightly generated in the magnets (cracks were generated in 4 out of 28 pieces, and chippings were 1 out of 28 pieces).
Occurred in pieces. ). At this time, the upper layer Oflon SK-2
When the film thickness was 20 μm, cracking and chipping were reduced to the range that could be manufactured (1 out of 28 cracks and chippings).
Occurred in pieces. ).

Although the embodiments of the present invention made by the inventor have been specifically described above, the present invention is not limited to the above embodiments, and can be variously modified without departing from the gist thereof. Needless to say. For example, when it is desired to soften the hardness of the coating film, a larger amount of a high molecular epoxy resin or the like can be added.

The present invention can be applied not only to the sintered magnet as in the above-described embodiment but also to various other magnets. Further, the soft paint applied to the surface of the magnet material is not limited to the rust preventive material as in the above-described embodiment, and other paints can be similarly applied.

[0035]

As described above, according to the present invention, damage such as cracking or chipping is caused by applying a coating material made of a predetermined soft material to a predetermined thickness or more on a magnet material. Magnetization can be performed satisfactorily without
It is possible to enhance the reliability and productivity of the thin and small magnet.

Further, according to the magnet and the method of manufacturing the same according to the present invention, high corrosion resistance and high water repellency can be obtained by the surface elasticity of the magnet.

Further, if the chamfering is performed at the same time, the coating can be evenly applied to the corners, and the above-mentioned effect can be further enhanced.

[Brief description of the drawings]

FIG. 1 is an explanatory longitudinal sectional view showing a structure of a barrel coating apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing a necessary critical line of a film thickness corresponding to the hardness of a coating material.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Storage container 2 Spray means 2a Nozzle 5 Casing 6 Motor 20 Rust prevention material supply pipe 21 Metering pump 22 Paint tank 23 Rust prevention material 25 Sintered magnet material

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4K062 AA01 BC30 FA16 5E040 AA02 AA03 AA06 BC05 BD01 CA01 HB05 HB14 NN05 NN17 5E062 CC03 CD04 CG07

Claims (7)

[Claims] 1. A magnet in which a predetermined coating material is applied in the form of a film on a surface of a magnet material and magnetized, wherein the coating material comprises a soft paint having a pencil hardness of 3H or less. Wherein the film thickness of the magnet is set to 15 μm or more. 2. A method of manufacturing a magnet in which a predetermined coating material is applied in the form of a film on a surface of a magnet material and then magnetized, wherein a soft paint having a pencil hardness of 3H or less is used as the coating material. A method for manufacturing a magnet, characterized in that the soft coating material is applied so that the film thickness becomes 15 μm or more. 3. The magnet according to claim 2, wherein before applying the soft material, a base treatment step for increasing the adhesion of the soft material to the surface of the magnet material is performed. Method. 4. The method for manufacturing a magnet according to claim 3, wherein the base treatment step includes a step of applying an epoxy resin-based paint or a surface roughening step of roughening the surface of the magnet material. 5. The method for producing a magnet according to claim 2, wherein a fluorine-containing paint having a rust-preventing action is used as the soft paint. 6. The magnet material is an Nd-based, Sm-C
3. The method for manufacturing a magnet according to claim 2, wherein one of an o-based and an alnico-based rare earth sintered metal material is used. 7. A magnet having a radius of 0.1
3. The method for manufacturing a magnet according to claim 2, wherein a curved chamfer of not less than mm is formed.