JPH11312604A - Laminated magnetic material and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the iron loss of a laminated magnetic material and to secure a mechanical strength of the laminated magnetic material to such a degree that the material can endure machining, etc., by laminating many thin ribbons of a magnetic material, such as the amorphous material, one upon another by using an insulating binder. SOLUTION: A laminated magnetic material is formed by binding a plurality of magnetic materials 1 with each other using a binder 2. Each magnetic material 1 has a thickness of 3-50 μm and surface roughness of <5 μm and the binder 2 has such a property that the binder 2 dissolves in a solvent and remains as a solid content when the solvent is evaporated. When the magnetic material 1 is alternately laminated with the binder 2, the thickness of each layer of the binder 2 is adjusted to 1-10 μm, so that the thickness may become larger than the surface roughness of the material 1. The laminated magnetic material is constituted of thin belts of the magnetic material 1 and the insulating binder 2. Two kinds of magnetic materials 1 composed of an amorphous ribbon body manufactured by the melt quenching method and a cold-rolled permalloy thin riffon are prepared. The amorphous material includes an Fe-Cu-Nb-Si system, Fe-B-Si-C system, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated magnetic material formed by binding a plurality of magnetic materials with a binder, and a method for producing the same.

[0002]

2. Description of the Related Art Printers, HDDs, CD-ROMs, DVs
D, motors used in watches and the like are required to reduce power consumption in view of battery life and environmental issues. In addition, a generator that supplies electric power to a portable information device is required to be small and have high power generation efficiency.
Reducing the power consumption of the motor is to reduce copper loss, iron loss, and mechanical loss. The copper loss therein is caused by Joule heat generated by the current flowing through the winding. Therefore, reducing the current as much as possible will reduce the copper loss. Iron loss is divided into eddy current loss and hysteresis loss, and largely depends on the characteristics of the soft magnetic material used for the motor. As its characteristics, it is desirable that the volume resistivity is large, the saturation magnetization is large, and the coercive force is small. The mechanical loss includes a bearing loss and a windage loss, and the bearing loss is usually dominant. The same applies to the case of a generator, but when the rotation speed of the rotor is high, reduction of iron loss particularly contributes to high-efficiency power generation. Recently, the amount of information has increased, the recording density of a storage device has been improved, and the resolution of an output device has been improved. When the motor rotates at high speed, copper loss, iron loss, and mechanical loss each increase, and power consumption increases.

[0003] In motors for these applications, silicon steel sheets, soft magnetic iron, permalloy, and the like have been mainly used.
These polycrystalline metal-based materials are formed into an ingot by a casting method, and then hot-worked and cold-worked to be processed into a sheet material having a required thickness. The thickness used for motors is 0.2 to 1.0 mm. It is processed into the shape of a stator or rotor by a press and used as a magnetic circuit to reduce eddy currents as much as possible. Had a thickness limit. It is also difficult to increase the volume resistivity of the polycrystalline metal by the third additive element, and there is a limit in reducing the eddy current.

[0004]

SUMMARY OF THE INVENTION The present invention aims to improve the characteristics of the soft magnetic material used in the above-described motors and generators for the purpose of reducing iron loss. In particular, it is to reduce eddy current loss by alternately laminating and fixing a thin magnetic material with an insulating layer. As a result, it is an object to provide a highly efficient motor with low power consumption.

Further, in the case of a soft magnetic material used for a motor or a generator, it is necessary to work into a complicated shape such as a stator or a rotor, and the working does not impair the magnetic properties and mechanical strength. It is to obtain a lamination method.

[0006]

According to a first aspect of the present invention, in a laminated magnetic material in which a plurality of magnetic materials are bonded with a binder, the thickness of the magnetic material is 3 to 50 μm and the surface roughness Ra is Ra. <5 μm, the binder has the property of being dissolved in a solvent and remaining as a solid when the solvent is evaporated, the magnetic material and the binder are alternately laminated, and the thickness t of the binder is 1 to 10 μm and t > Ra.

According to a second aspect of the present invention, there is provided a method for manufacturing a laminated magnetic material in which a plurality of magnetic materials are bonded with a binder, wherein (a) applying a binder dissolved in a solvent to a magnetic material having a thickness of 3 to 50 μm. (B) subsequently evaporating the solvent to form a binder layer having a thickness of 1 to 10 μm on the magnetic material; and (c) laminating a desired number of sheets and fixing them by pressing. Features.

According to a third aspect of the present invention, there is provided a method of manufacturing a laminated magnetic material in which a plurality of magnetic materials are bonded with a binder, wherein (a) applying a binder dissolved in a solvent to a magnetic material having a thickness of 3 to 50 μm. (B) subsequently evaporating the solvent to form a binder layer having a thickness of 1 to 10 μm on the magnetic material; (c) leaving the mixture at room temperature for 24 to 480 hours; It is characterized by comprising a step of laminating and fixing by pressing.

According to a fourth aspect, the surface roughness Ra of the magnetic material according to the second and third aspects is Ra <5 μm,
Further, the binder thickness t is t> Ra.

In a fifth aspect, the volume ratio of the binder to the solvent according to the second and third aspects is 1: 5 to 1: 1.

According to a sixth aspect of the present invention, the thickness of the magnetic material is reduced to 1 to 3 on the magnetic material by evaporating the solvent.
The evaporation temperature in the step of forming a 10 μm binder layer is room temperature to 70 ° C.

According to a seventh aspect, the speed at which the magnetic material is sent to (a) to (d) according to the second and third aspects is 1 to 50 c.
m / s.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION A laminated magnetic material comprises a magnetic material ribbon and an insulating binder. Three types of magnetic materials shown in Table 1 were prepared. One is an amorphous ribbon produced by a liquid quenching method, and the other is a permalloy cold-rolled. In the case of amorphous, in addition to this composition, Fe-Cu-Nb-B-Si system, Fe-B-Si-
C-type or the like can be used in the same manner, and is not limited to a magnetic material having a specific composition.

[0014]

[Table 1]

Compared to conventional polycrystalline metal magnetic materials such as permalloy, silicon steel plate, and pure iron, amorphous magnetic materials are characterized by high magnetic permeability, low coercive force, and high electric resistance. Since it is manufactured by the liquid quenching method, a ribbon having a thickness of several tens of μm can be easily obtained. In particular, in order to reduce iron loss, it is required that the coercive force be small in order to reduce hysteresis loss, and that the electric resistance be large in order to reduce eddy current loss. However, the lamination method of the present invention,
It is not limited to amorphous, it is flexible,
If the thickness of the ribbon is 3 to 50 μm, it can be basically laminated. In this evaluation, a sample in a wide range of 3 to 50 μm was not available. However, as the thickness increases, the thickness of the binder decreases relatively, so that the effect obtained by the present invention is relatively reduced. Only
It does not impair the effectiveness of the present invention. Further, it is difficult to produce a ribbon having a thickness of 3 μm or less due to a problem of mechanical strength in both the liquid quenching method and the cold rolling method, and even if a ribbon can be produced, it is difficult to handle it at the time of lamination.

FIG. 1A shows an ideal laminated state, while FIG. 1B schematically shows the actual laminated state with a little exaggeration. If the surface roughness of the magnetic material 1 is rough, the magnetic materials 1 come into contact with each other as in the contact portion 13 and hinder lamination of a uniform thickness, thereby hindering reduction of eddy current. Further, when the surface roughness is rough, the bubbles 12 shown in FIG. 1B are easily generated, and the strength of the lamination is impaired. Therefore, it is preferable that the surface roughness Ra is Ra <5 μm. More preferably, Ra <1 μm. Further, the thickness t of the binder 2 depends on the surface roughness Ra of the magnetic material 1.
By increasing the thickness, the binder can cover the unevenness, and as a result, the magnetic materials 1 can be properly bonded to each other. When the thickness t of the binder 2 is smaller than the surface roughness Ra of the magnetic material 1, the magnetic materials 1
The contact is made like the contact portion 13 in (b), which leads to the generation of an eddy current. Table 1 shows the magnetic materials used in the four experiments. The surface roughness of the amorphous 2705M of A and the amorphous 2714A of B were both 1 μm or less. The surface roughness of the C permalloy PA and the silicon steel sheet of D were both about 5 μm. Silicon steel plate for reference,
The properties of a 0.25 mm thick plate are shown, and A, B, C
Can be compared with those laminated.

It is necessary that the binder spreads thinly when it is dissolved in a solvent and applied to the surface of a magnetic material, and then only the resin component remains when the solvent is dried. In addition, it is necessary that the magnetic materials have high adhesive strength, and in particular that they do not peel off even when the laminated magnetic materials are bent or subjected to mechanical processing. Four types shown in Table 2 were prepared as binders. All are dissolved in a solvent and satisfy the above requirements.

As the solvent, types of ethyl acetate and methyl ethyl ketone were prepared. All have the property of dissolving the resins shown in Table 2, having an appropriate boiling point and evaporating. In consideration of recent environmental problems, it is necessary to use a manufacturing apparatus that recovers evaporated solvent as much as possible.

[0019]

[Table 2]

Table 3 shows the combinations of the experiments and the evaluation results of the lamination strength. Lamination experiments were performed with the number of laminated magnetic materials being 10 and the target thickness of the binder being about 4 μm. The average laminated thickness was calculated by measuring the thickness of the laminated magnetic material at nine locations with a micrometer and calculating the average value.

The lamination ratio = (thickness of one magnetic material × the number of laminations) ÷ the thickness after lamination was defined as lamination ratio> 80% in all cases.

[0022]

[Table 3]

The evaluation method of the lamination strength is as follows. The laminated magnetic material is incorporated into a wristwatch by wire discharge cutting. The shape of the stator of the step motor (dimensions: total length 10 mm, width 4 mm)
After bending to 15 degrees once with a cantilever beam, each magnetic material was inspected with a stereoscopic microscope at 20x to see if there was any separation between magnetic materials. Those that were peeled were evaluated as x, and those that were slightly peeled in the middle were evaluated as Δ.

From Table 3, it can be seen that the magnetic material is either amorphous A or B, and the binder is bisphenol A type epoxy resin of e, which is unsuitable in terms of lamination strength.
As a result, it was found that the partially saponified montanic acid ester wax, the modified polyester resin g, and the phenol butyral resin h were good, and that the solvent was both ethyl acetate and methyl ethyl ketone in terms of the average lamination thickness.

Next, the manufacturing process will be described. FIG. 2 shows a manufacturing process according to the second aspect. The magnetic material 1 is wound around the material supply roller 3 and is sequentially fed. A solvent 5 in which a binder is dissolved in a container is disposed at a lower portion, and an application roller 4 is disposed at an upper portion thereof. Further, a solvent recovery device 9 for recovering the evaporated solvent is disposed at an upper portion. At this time, the condition that the application roller 4 is in good contact with the magnetic material 1 is a condition for uniform application. The volume ratio of the binder to the solvent is preferably from 1: 5 to 1: 1.
When the binder concentration is high, the coating tends to be thick, and when the binder concentration is low, the opposite tendency occurs. After passing through the solvent drying and recovery unit 6, the solvent is heated from below and the solvent evaporates,
It is collected in the upper collecting device. If heating is performed rapidly at this time, the solvent is dried only on the surface, and the solvent is trapped in the middle part. Therefore, it is preferable to dry gently. A drive roller 7 is arranged next and the magnetic material 1
To prevent loosening. If the tension is too high, the magnetic material 1 will break, so care must be taken. An appropriate tension is determined from the strength calculated from the cross-sectional area of the magnetic material 1 and the tensile strength. Thereafter, a cutting machine 10 for cutting the magnetic material 1,
A take-up roller 8 is provided. The winding roller 8 is preferably as large as possible because the curvature after winding becomes a warp after lamination. When the size of the product is small, the size of the winding roller 8 can be somewhat small. When ten layers of the magnetic material 1 are stacked, the magnetic material 1 may be wound around the winding roller 10 ten times and cut. By cutting one place after winding, a laminated magnetic material of 10 layers is completed. The number of windings of the winding roller 8 may be determined according to the number of stacked layers. Each roller is selected in consideration of the frictional force with the magnetic material 1, the solvent resistance, and the like. For example, a silicon rubber roller is suitable.

Next, FIG. 3 shows a manufacturing process according to claim 3. Although it is almost the same as FIG. 2, the last winding is different. After the cutting machine 10, a winder 11 for drying is arranged. It is considered that the magnetic material 1 coated with the binder 2 is spread as much as possible in a space as narrow as possible. However, it is not always necessary when there is sufficient space for drying. By leaving it at room temperature in this state, the solvent is gradually dried sufficiently to the inside, and it becomes difficult to generate bubbles 12 and the like after lamination. Drying time at room temperature varies depending on room temperature and humidity, but in Japan it is 24 to 1 in summer.
It is around 68 hours, 96-480 hours in winter, and between spring and autumn. At this time, avoid a place exposed to the direct sunlight of the sun, and preferably have a well-ventilated shade. However, in the case of a highly airtight room, sufficient attention must be paid to ventilation since the solvent is dispersed in the air. When the solvent is sufficiently dried,
The laminated magnetic material is completed by winding the same number of layers on the winding roller 8 shown in FIG. The laminated magnetic material thus produced is processed into a motor stator and used.

Table 4 shows that amorphous 1 of A was used as a magnetic material.
705M, g modified polyester as the binder, and ethyl acetate as the solvent. The experimental conditions for the volume ratio of the binder to the solvent, the feed rate, ie, the moving speed of the magnetic material, and the drying temperature of the solvent drying and recovery unit 6 in FIG. It is. The number of laminated magnetic materials is 10 in each case.
In Table 4, the feed speed indicates the speed at which the magnetic material 1 moves, and the drying temperature indicates the set temperature for drying the solvent and heating the recovery unit 6 in FIG. The generation of bubbles
It is a result of observing the presence or absence of air bubbles with a 20 × stereo microscope after mechanically peeling off the magnetic material after lamination.

[0028]

[Table 4]

Table 5 shows the results of the experiment. A good result is obtained when the volume ratio of the binder to the solvent is 1: 1 to 1: 5 (the present inventions 6, 7, and 8), and the thickness of the laminate tends to increase as the binder concentration increases. Be looked at. However, in the case of the volume ratio of 1:10 (Comparative Example 4), the average lamination thickness was reduced, and as a result, the lamination strength was insufficient. Regarding the feed speed, when the feed speed is high, the coating amount of the binder tends to decrease, and the result is good in the case of 10, 40 cm / s (the present invention 7, 9). The average lamination thickness was reduced, and the lamination strength was also poor. As for the drying temperature, a tendency to generate air bubbles is observed when the drying temperature is increased.
10) was good, but at 100 ° C. (Comparative Example 6)
The laminate had poor lamination strength and bubbles were generated.

[0030]

[Table 5]

[0031]

According to the present invention, in a soft magnetic material used for a magnetic circuit such as a motor, iron loss is reduced by laminating a thin strip of a magnetic material such as an amorphous layer in a multilayer using an insulating binder. be able to. In particular, by laminating the magnetic material ribbons, the effect of being able to limit the region where the eddy current occurs is obtained. By reducing the thickness of the binder that binds the ribbon of the magnetic material as much as possible, the lamination rate of the magnetic material can be improved, and as a result, the saturation magnetization can be increased. In addition, by making the thickness of the binder thin and uniform, it is possible to secure mechanical strength that can withstand mechanical processing and the like. Further, by gradually evaporating the solvent in which the binder is dissolved, the generation of bubbles is suppressed, and a stable binder thickness and mechanical strength can be obtained.

[Brief description of the drawings]

FIG. 1A is a view showing an ideal laminated state of a laminated magnetic material. (B) The figure which showed typically the laminated state of the actual laminated magnetic material.

FIG. 2 is a diagram illustrating a first manufacturing process of a laminated magnetic material.

FIG. 3 is a diagram illustrating a second manufacturing process of the laminated magnetic material.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Magnetic material 2 Binder 3 Supply roller 4 Application roller 5 Solvent which melted binder 6 Solvent drying and recovery device 7 Drive roller 8 Winding roller 9 Solvent recovery device 10 Cutting machine 11 Drying winder 12 Bubbles 13 Contact part

Claims (7)

[Claims] 1. A laminated magnetic material comprising a plurality of magnetic materials joined by a binder, wherein the thickness of the magnetic material is 3 to 5
0 μm, the surface roughness Ra is Ra <5 μm, the binder has the property of being dissolved in a solvent and remaining as a solid when the solvent is evaporated, and the magnetic material and the binder are alternately laminated, and the binder A laminated magnetic material having a thickness t of 1 to 10 μm and t> Ra. 2. A method for producing a laminated magnetic material in which a plurality of magnetic materials are bonded with a binder, wherein (a) applying a binder dissolved in a solvent to a magnetic material having a thickness of 3 to 50 μm; b) a step of forming a binder layer having a thickness of 1 to 10 μm on the magnetic material by evaporating the solvent, and (c) a step of laminating a desired number of layers and fixing them by pressing. Magnetic material. 3. A method for producing a laminated magnetic material in which a plurality of magnetic materials are bonded with a binder, wherein (a) applying a binder dissolved in a solvent to a magnetic material having a thickness of 3 to 50 μm; b) then evaporating the solvent to form a binder layer having a thickness of 1 to 10 μm on the magnetic material, (c) leaving to stand at room temperature for 24 to 480 hours,
(D) A laminated magnetic material comprising a step of laminating a desired number of sheets and fixing them by pressing. 4. The magnetic material according to claim 1, wherein the surface roughness Ra is Ra <Ra <4.
4. The laminated magnetic material according to claim 2, wherein the thickness is 5 μm and the binder thickness t is t> Ra. 5. The volume ratio of the binder and the solvent is 1:
The method for producing a laminated magnetic material according to claim 2, wherein the ratio is 5 to 1: 1. 6. The method according to claim 1, wherein the evaporating temperature in the step (b) of forming a binder layer having a thickness of 1 to 10 μm on the magnetic material by evaporating the solvent is room temperature to 70 ° C. 4. The method for producing a laminated magnetic material according to items 2 and 3. 7. The method according to claim 2, wherein the speed at which the magnetic material is sent to (a) to (d) is 1 to 50 cm / s.
4. The method for producing a laminated magnetic material according to claim 3.