JPH06231936A - Magnetic filler - Google Patents

Abstract

PURPOSE:To acquire a magnetic filler for filling up a clearance between magnetic substances which can reduce magnetic clearance remarkably by mixing spinel soft magnetic ferrite powder, i.e., magnetic powder with resin. CONSTITUTION:Spinel soft magnetic ferrite powder of an average grain diameter of about 1 to 100mum is mixed about 25 to 70vol% to resin for acquiring magnetic filler. During the process, thermosetting resin containing about 0 to 60wt.% volatile element or thermoplastic resin containing about 20 to 60wt.% volatile element is used as resin. The magnetic filler is used for filling up a clearance between magnetic substances. Thereby, it is possible to greatly reduce the leakage of magnetic flux and to remarkably improve the magnetic characteristics of a magnetic part comprised of a plurality of magnetic substances.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic filler obtained by mixing a spinel soft magnetic ferrite powder with a resin.

[0002]

2. Description of the Related Art Conventionally, as a filler, there are a filler in which a non-magnetic powder is mixed with a resin and a filler in which a conductive powder is mixed.

[0003]

When a plurality of magnetic materials are combined to obtain one magnetic component, the magnetic components constituting the component are largely distorted due to shape distortion and thermal expansion. There is a gap. A large demagnetizing field is generated due to the gap between the magnetic bodies thus generated, and a remarkable leakage of magnetic flux occurs. As a result, there has been a problem that the magnetic properties of the magnetic parts obtained by the combination are significantly deteriorated.

As a method of reducing the gap between the magnetic bodies in order to prevent the deterioration of the magnetic characteristics of the magnetic parts, there is a method of reprocessing the magnetic body to be used with high dimensional accuracy. However, with this method, the manufacturing cost of the magnetic component is significantly increased, which is a serious industrial problem.

An object of the present invention is to mix spinel soft magnetic ferrite powder, which is magnetic powder, with a resin,
It is an object of the present invention to provide a magnetic filler capable of filling gaps between magnetic bodies and significantly reducing magnetic gaps.

[0006]

In the filler of the present invention, a magnetic filler is obtained by mixing spinel soft magnetic ferrite powder, which is magnetic powder, with a resin.

[0007]

The magnetic filler is obtained by mixing the spinel soft magnetic ferrite powder with the resin. By using this magnetic filler to fill the gaps between magnetic bodies, it is possible to significantly reduce the leakage of magnetic flux, and as a result, the magnetic characteristics of magnetic parts made up of multiple magnetic bodies are significantly improved compared to conventional products. Can be made.

[0008]

EXAMPLES Examples of the present invention will be described below.

[0009]

Example 1 Spinel soft magnetic ferrite powder [(Ni _0.5 .Zn _0.5 )] having an average particle size of 0.5 to 150 μm
O.Fe ₂ O ₃ ] 100 g (18.76 cc) and thermosetting epoxy resin 22.51 g (18.76 cc) were mixed for 1 hour with a kneader (powder volume fraction 50 vol%),
A magnetic filler was prepared.

As an evaluation of the above-mentioned filler, a ferrite sintered body ring core (outer diameter 20 mm, inner diameter 10 mm, height 5 mm) cut in half in the diameter direction was prepared.
The cut ring core was fixed to a jig so that the distance between the cut surfaces was 0.5 mm, and the gap was filled with the above-mentioned magnetic filler and non-magnetic filler containing no magnetic powder. It was prepared and heat cured at 100 ° C. for 2 hours. Next, the coated copper wire was wound 10 times around this ring core, the inductance at this time was measured, and the rate of increase of the inductance when the magnetic filler was used with respect to the non-magnetic filler was evaluated.

FIG. 1 is a graph showing the rate of increase in inductance in the case of using a filler prepared by changing the average particle diameter of ferrite powder to 0.5 to 150 μm with respect to the case of using a non-magnetic filler. is there. In the figure, the mark X indicates that the filler has peeled from the core. According to FIG. 1, it can be seen that the inductance is high in the range of the average particle diameter of 1 to 100 μm, and the leakage of the magnetic flux from the gap between the magnetic materials is effectively reduced. When the average particle diameter is less than 1 μm, the filler peels off at the core cross section, and does not function as a filler in practical use. When the average particle size is larger than 100 μm, the rate of increase in inductance is low, which is not industrially useful.

In Example 1, the composition of the spinel soft magnetic ferrite powder was [(Ni _0.5 .Zn
_{Although 0.5} ) O.Fe ₂ O ₃ ] magnetic powder was used, similar effects can be obtained with spinel soft magnetic ferrite powders having other compositions.

[0013]

Example 2 50 g of thermosetting silicone resin was mixed with spinel soft magnetic ferrite powder [(Mn
_0.5 · Zn _0.5 ) O · Fe ₂ O ₃ ] is 0 to 883 g.
(0 to 80 vol% with respect to the resin content) and 12.5 g of toluene (volatile component 20 wt%) as a diluting solvent were mixed for 1 hour with a kneading machine to prepare a magnetic filler.

For the evaluation of the above-mentioned filler, a ring core made of a ferrite sintered body (outer diameter 20 mm,
An inner diameter of 10 mm and a height of 5 mm) was cut in half in the diameter direction. The cut ring core is fixed to a jig so that the distance between the cut surfaces is 0.5 mm, and the gap is filled with the magnetic filler described above and a non-magnetic filler containing no magnetic powder. Was prepared and heat cured at 100 ° C. for 2 hours. Next, the coated copper wire was wound 10 times around this ring core, the inductance at this time was measured, and the rate of increase of the inductance when the magnetic filler was used with respect to the non-magnetic filler was evaluated.

FIG. 2 shows the case of using a non-magnetic filler in the case of using a filler prepared by changing the volume fraction of spinel soft magnetic ferrite powder from 0 to 80% as an evaluation of the filler. It is a figure which shows the increase rate of the inductance with respect to. In FIG. 2, the mark X indicates that the strength of the filler was weak and the shape could not be maintained. According to this figure, it can be seen that the inductance is high in the range of the volume fraction of the ferrite powder of 25 to 70 vol%, and the leakage of the magnetic flux from the gap between the magnetic materials is effectively reduced. 25% volume fraction
If it is less than the above, the increase rate of the inductance is remarkably low because the content of the powder is small, and the effectiveness as a magnetic filler is not recognized. Further, when the volume fraction of the powder is more than 70%, the strength of the filler is low and the filler does not practically function.

[0016]

[Example 3] To 50 g of a thermosetting epoxy resin, 0 to 200 g of toluene as a diluent solvent (0 to 80 wt.
%) And mixed with it, spinel soft magnetic ferrite powder [(Mn _0.5 .Zn _0.5 ) O having an average particle diameter of 10 μm].
・ Fe ₂ O ₃ ] 223 g (50 vol with respect to resin content)
%) Was mixed with a kneader for 1 hour to prepare a magnetic filler.

As an evaluation of the above-mentioned filler, a ring core made of a ferrite sintered body (outer diameter 20 mm,
An inner diameter of 10 mm and a height of 5 mm) was cut in half in the diameter direction. The cut ring core is fixed to a jig so that the distance between the cut surfaces is 0.5 mm, and the gap is filled with the magnetic filler described above and a non-magnetic filler containing no magnetic powder. Was prepared, and the solvent (volatile component) was removed and the resin was thermoset at 100 ° C. for 3 hours. Next, the coated copper wire was wound 10 times around this ring core, the inductance at this time was measured, and the rate of increase of the inductance when the magnetic filler was used with respect to the non-magnetic filler was evaluated.

FIG. 3 shows the rate of increase of the inductance when using a filler prepared by changing the amount of toluene mixed as a volatile component from 0 to 80 wt% with respect to the case of using a non-magnetic filler. It is a figure. According to FIG.
It can be seen that the inductance is high in the range of the mixed amount of volatile components of 0 to 60 wt%, effectively reducing the leakage of the magnetic flux from the gap between the magnetic materials. When the mixing amount of the volatile component is more than 60 wt%, the increase rate of the inductance is low and it is not industrially beneficial. This is because when the volatile component is more than 60 wt%, the filler is separated from the magnetic material due to the volume contraction of the resin due to the evaporation of the volatile component,
This is because when the filler itself is cracked, a magnetic gap is generated and a loss of magnetic flux occurs, which deteriorates the magnetic characteristics of the magnetic component.

Further, although toluene was used as the volatile component in the diluent solvent in the examples, the same effect can be obtained with other solvents as long as it dissolves the resin.

[0020]

Example 4 Polyurethane resin 50 which is a thermoplastic resin
g to 0 to 200 of methyl ethyl ketone as a diluting solvent
g (volatile component 0 to 80 wt%), and mixed with this is spinel soft magnetic ferrite powder with an average particle diameter of 10 μm [(M
223 g (powder 50 vol% with respect to the resin) of n _0.5 · Zn _0.5 ) O · Fe ₂ O ₃ ] was mixed for 1 hour with a kneader to prepare a magnetic filler.

As the evaluation of the above-mentioned filler, a ring core made of a ferrite sintered body (outer diameter 20 mm) was used as in Example 1.
An inner diameter of 10 mm and a height of 5 mm) was cut in half in the diameter direction. The cut ring core is fixed to a jig so that the distance between the cut surfaces is 0.5 mm, and the gap is filled with the magnetic filler described above and a non-magnetic filler containing no magnetic powder. Was prepared, and the solvent (volatile component) was removed at 80 ° C. for 3 hours. Next, the coated copper wire was wound 10 times around this ring core, the inductance at this time was measured, and the rate of increase of the inductance when the magnetic filler was used with respect to the non-magnetic filler was evaluated.

FIG. 4 is a diagram showing the rate of increase in inductance when a filler prepared by changing the amount of methyl ethyl ketone mixed as a volatile component to 0 to 80 wt%. According to FIG. 4, the mixing amount of volatile components is 20 to 6
It can be seen that the inductance is high in the range of 0 wt% and the leakage of the magnetic flux from the gap between the magnetic materials is effectively reduced. If the volatile component is less than 20 wt%, the viscosity of the filler is extremely high, and the filler does not function as a practical filler. This situation is indicated by a cross mark in FIG. Further, when the volatile component is more than 60 wt%, the rate of increase in inductance is low, which is not industrially beneficial. This is because when the volatile component is more than 60 wt% as in Example 3, the filler is separated from the magnetic material due to the volume contraction of the resin due to the evaporation of the volatile component, or the filler itself is cracked. This is because a magnetic gap is generated and a loss of magnetic flux occurs, which deteriorates the magnetic characteristics of the magnetic component.

Further, in the examples, methyl ethyl ketone was used as the volatile component in the diluting solvent, but other than that, the same effect can be obtained as long as it is a solvent capable of dissolving the resin.

[0024]

Example 5 Vinyl acetate resin 50 g which is a thermoplastic resin
In addition, 0 to 883 g (0 to 80 vol% of the powder relative to the resin content) of spinel soft magnetic ferrite powder [(Mn _0.5 .Zn _0.5 ) O.Fe ₂ O ₃ ] having an average particle diameter of 10 μm.
Were mixed in a kneading machine for 1 hour in a heated and melted state to prepare a magnetic filler.

As the evaluation of the above-mentioned filler, as in Example 1, a ring core made of a ferrite sintered body (outer diameter 20 mm,
An inner diameter of 10 mm and a height of 5 mm) was cut in half in the diameter direction. The cut ring core was fixed to a jig so that the distance between the cut surfaces was 0.5 mm. The gap was prepared by heating and melting the above-mentioned magnetic filler and non-magnetic filler containing no magnetic powder, and thereafter, the filler was solidified by natural cooling. next,
A coated copper wire was wound around this ring core 10 times, the inductance at this time was measured, and the rate of increase of the inductance when a magnetic filler was used with respect to a non-magnetic filler was evaluated.

FIG. 5 shows the rate of increase in inductance when a spin-melt soft magnetic ferrite powder was prepared by changing the volume fraction of the spinel soft magnetic ferrite powder to a hot-melt type, so-called hot-melt type magnetic filler. It is a figure. In FIG.
The cross mark indicates that the strength of the filler was weak and the shape could not be retained. According to FIG. 5, as in Example 2, the inductance is high in the range of the volume fraction of the ferrite powder of 25 to 70 vol%, and the leakage of the magnetic flux from the gap between the magnetic materials is effectively reduced. I understand. Volume fraction 25
If it is less than%, the increase rate of the inductance is remarkably low because the content of the powder is small, and the effectiveness as a magnetic filler is not recognized. Further, when the volume fraction of the powder is more than 70%, the strength of the filler is low and the filler does not practically function.

Although vinyl acetate resin was used as the resin in the examples, similar effects can be obtained with other thermoplastic resins such as vinyl chloride resin and urethane resin.

Further, in the embodiment, as a method of mixing the powder and the resin, the resin is heated and melted to perform the mixing, but other than that, the resin is dissolved in the solvent and mixed with the powder, and then the solvent is evaporated. Similar effects can be obtained by mixing by the method.

[0029]

As described above, according to the present invention, by mixing the spinel soft magnetic ferrite powder with the resin, the leakage of the magnetic flux in the gap in the magnetic component can be effectively reduced and the loss of the magnetic flux can be reduced. It is possible to obtain a filler having magnetic properties that can be significantly reduced.

[Brief description of drawings]

FIG. 1 is a graph showing the rate of increase in inductance in the magnetic filler of Example 1 when the average particle diameter is changed and when a non-magnetic filler is used.

FIG. 2 is a diagram showing the rate of increase in inductance in the magnetic filler in Example 2 when the volume fraction of powder was changed and when a non-magnetic filler was used.

FIG. 3 is a diagram showing an increase rate of inductance in the magnetic filler in Example 3 when the mixing ratio (volatile content ratio) of volatile components is changed and when a non-magnetic filler is used.

FIG. 4 is a diagram showing the rate of increase in inductance in the magnetic filler of Example 4 when the mixing ratio (volatile content ratio) of volatile components was changed and when a non-magnetic filler was used.

FIG. 5 is a graph showing the rate of increase in inductance in the heating and melting type magnetic filler in Example 5 when the volume fraction of powder is changed and when a non-magnetic filler is used.

Claims (4)

[Claims] 1. A spinel soft magnetic ferrite powder having an average particle diameter of 1 to 100 μm as a magnetic filler,
A magnetic filler characterized by being mixed in an amount of 25 to 70 vol% with respect to a resin. 2. The magnetic filler according to claim 1, wherein a thermosetting resin is used as the resin, and the thermosetting resin contains a volatile component in an amount of 0 to 60 wt%. 3. The magnetic filler according to claim 1, wherein a thermoplastic resin is used as the resin and the volatile component is contained in an amount of 20 to 60 wt% with respect to the thermoplastic resin. 4. The magnetic filler according to claim 1, wherein a thermoplastic resin is used as the resin, and a mixture of the thermoplastic resin and the spinel soft magnetic ferrite powder is heated and melted to fill the filled portion and then cooled. A magnetic filler characterized by solidifying.