JPH0969443A - Case housing type magnetic core - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a case housing type magnetic core, which has a high reliability, which is required as a magnetic component, and generates little noise. SOLUTION: When the mass of a magnetic core 11, the Young's modulus subsequent to a curing of a bonding agent 13, the total thickness of the bonding agent 13 which is provided in the gaps between the end faces of the magnetic core 11 and cases 121 and 122 , and the total area of the core 11, which is bonded to the cases 121 and 122 with the agent 13 between the core 11 and the cases 121 and 122 , are respectively assumed m[kg], E[N/m<2> ], d[m] and A[m<2> ], a case housing type magnetic core 10 is constituted so as to satisfy a relation, 3×10<6> <=A.E/(m.d)<=1×10<8> .

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a case-storing type magnetic core, for example, a case-storing type magnetic core used for a magnetic component used in an electronic circuit.

[0002]

2. Description of the Related Art In a magnetic component composed of a magnetic core and a coil wound around the magnetic core, the coil is formed by using a wire having an insulation coating to prevent a short circuit during the winding. . At that time, if the wire is wound directly on the magnetic core, the magnetic core is harder than the insulating coating, and thus the insulating coating of the wire may be damaged during the winding, and the coil may be short-circuited.

In order to prevent the occurrence of such damage to the insulating coating of the wire, conventionally, the magnetic core is housed in a resin case and then the coil is wound around the case, or the coil is preliminarily wound. After being wound around a resin bobbin, the bobbin is attached to the magnetic core. Which method is used to protect the insulating coating is selected according to the shape of the target magnetic core,
For example, in the case of a magnetic core using a magnetic alloy ribbon, the former method is adopted because the magnetic core has a substantially annular shape.

When the magnetic core is housed in the case, unless the magnetic core is fixed to the case, the magnetic core moves in the case and collides with the wall surface of the case during transportation, so that stress acts on the magnetic core, and It may be destroyed or the magnetic characteristics of the magnetic core may be deteriorated. In addition, the impact of the magnetic core colliding with the wall surface of the case may be propagated to other parts, which may adversely affect those parts. Therefore, when forming a case-housing type magnetic core, it is essential to prevent the magnetic core from moving within the case in order to ensure reliability as a magnetic component.

As a method of preventing the movement of the magnetic core in the case, there is a method of making the inner wall of the case the same size as the outer dimension of the magnetic core. When forming the coil around the case,
The case may be wound around the wire and deformed, and stress may be applied to the magnetic core. Further, since the magnetic core is in direct contact with the case, the vibration of the magnetic core is easily propagated to the case, and a large noise is generated when the magnetic core is excited.

For this reason, conventionally, a case having an inner diameter larger than the outer shape of the magnetic core is prepared, and an elastic body is arranged in a gap between the case and the magnetic core. If the case is made significantly larger than the magnetic core, the magnetic flux in the gap between the magnetic core and the case must be taken into consideration. A slightly larger case is used.

[0007]

When the elastic body is arranged in the gap between the magnetic core and the case as described above, some noise reduction effect can be obtained. However, the strain due to the increase in volume of the elastic body at the time of hardening causes the vibration absorbing force of the elastic body to be lost, and the gap between the magnetic core and the case is originally 1 mm or less. In some cases, the elastic body may not be able to sufficiently exhibit the vibration absorbing force, and the noise reduction effect due to the arrangement of the elastic body is insufficient.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a case storage type magnetic core which has high reliability as a magnetic component and produces a small noise.

[0009]

A case storage type magnetic core according to the present invention is a case storage type magnetic core in which a magnetic core is fixed to a case in which the magnetic core is stored with an adhesive, and the mass of the magnetic core is m [ kg], the Young's modulus of the adhesive after curing is E [N
/ M ² ], the total thickness of the adhesive provided in the gap between the magnetic core end surface and the case is d [m], and the total adhesive area between the magnetic core end surface and the case due to the adhesive is A [m ² ]. Sometimes 3 × 10 ⁶ [N / kg · m] ≦ A · E / (m · d) ≦ 1 × 10
⁸ [N / kg · m] is formed to satisfy the relationship.

That is, in the case-storing type magnetic core according to the present invention, it is possible to prevent the vibration of the magnetic core from propagating to the case by constructing so as to satisfy the relational expression A · E / (m · d) ≦ 1 × 10 ^8. Suppressed, 3 × 10 ⁶ ≦ A · E / (m
By ensuring that the relational expression d) is satisfied, the magnetic core is securely fixed to the case. This prevents the vibration of the magnetic core due to excitation from propagating to the case, and prevents the magnetic core from moving inside the case during transportation, and has high reliability as a magnetic component. In addition, it is possible to obtain a case-storage type magnetic core that generates less noise.

It is desirable that the case used for the case-holding type magnetic core of the present invention has a closed structure. Further, the present invention is applicable to magnetic cores made of various materials such as amorphous alloys (for example, Fe-based amorphous alloys), silicon steel, ferrite, dust, etc., but particularly to magnetic cores made of amorphous alloys. When applied, the noise reduction effect is remarkable.

[0012]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in detail below with reference to the drawings. The configuration of the case-storage type magnetic core according to the present invention will be described with reference to FIG. As shown schematically in the figure, the case-storing type magnetic core 10 includes a magnetic core 11 and a case 1.
It is manufactured by fixing 2 ₁ and 12 ₂ to each other with an adhesive 13. At that time, the mass of the magnetic core 11 is m [k
g], and when the average gap length between the case and the magnetic core in the state where the magnetic core 11 is housed in the case 12 (that is, the average thickness of the adhesive provided between the case and the magnetic core) is d [m], Using the adhesive 13 whose Young's modulus after curing is E [N / m ² ], the adhesive to be used and the adhesive to be used are selected so that the total adhesive area A [m ² ] by the adhesive satisfies the following formula The area to be applied is determined.

3 × 10 ⁶ ≦ A · E / (m · d) ≦ 1 × 10 ⁸ Adhesive points with the adhesive 13 are set so as to have high symmetry as shown in the figure, and the total adhesive area is adjusted Is performed by adjusting the adhesion area per one place or adjusting the number of adhesion places.

The case-storage type magnetic core 10 shown in the drawing is
Although the adhesive 13 is provided only on one side of the magnetic core, the case-storing type magnetic core may be configured by providing the adhesive 13 on both sides of the magnetic core. In such a case, both ends of the magnetic core are The sum of the thicknesses of the adhesives provided on the surfaces is d.

The structure and performance of the case-contained type magnetic core will be described more specifically below with reference to FIGS. 1 to 5. In the experiments by the present inventors, as the magnetic core 11, S
Amorphous magnetic alloy ribbon, which is a Fe-based amorphous alloy containing i and B (trade name: Metgla, manufactured by Allied Signal Co., USA)
s2605S-2) outer diameter 27.0m
m, an inner diameter of 15.0 mm, and a height of 10.0 mm, which was heat-treated at about 470 ° C., and used as the case 12, the outer diameter was 27.7 mm, the inner diameter was 14.7 mm, and the height was 1.
A case of 0.3 mm (both internal dimensions) (resin used as case material is Toray, trade name: 1184G-30) was used.

As the fixing adhesive (elastic body) 13, a fluid silicone rubber (manufactured by Toray Dow Corning Silicone, trade name: SE9186), an epoxy adhesive (manufactured by Ciba Geigy, trade name: AV138), The magnetic core 11 and the case 1 are made by using three kinds of adhesives having different properties such as silicone gel (trade name: αGEL manufactured by Siegel Co.).
Several types of case-storage type magnetic cores having different total adhesion areas with 2 were produced.

Further, as in the conventional case, a case-storing type magnetic core in which an adhesive is applied to the entire surface of both laminated end faces of the magnetic core 11 was also manufactured. In each case storage type magnetic core manufactured as described above,
A sample in which a coil was formed by winding 31 turns of a 1.0 mmφ magnetic wire was used as a sample, and a fixing test and a noise measurement test were performed on each of the manufactured samples.

The fixing test is a test of the fixing condition of the magnetic core to the case. When the case-holding type magnetic core is supported by hand and shaken strongly in the direction parallel to the laminated end face of the magnetic core, the movement of the magnetic core is felt. It was said that it failed.

In the noise measurement test, as shown schematically in FIG. 2, when the excitation signal is supplied to the coil 15 wound around the case-housing core 10, the noise level generated by the case-housing core 10 is measured. With the microphone 21 installed 200 mm away from the center of the case-holding type magnetic core 10.
It was carried out by measuring by.

FIG. 3 shows the structure of the excitation circuit used in the noise measurement test. As shown in the figure, the exciting circuit is composed of a signal generator 22, a power amplifier 23, and a current source 24. In this exciting circuit, pink noise generated by the signal generator 22 is 3.6 V by the power amplifier 23. _rms
The DC current of 6 A output from the current source 24 is superimposed on the amplified pink noise and the coil 15
The excitation signal to be supplied to is obtained.

In the noise measurement test, the noise level is the sound pressure level at which the center frequency of the 1/3 octave band measured through the microphone 21 is 10 kHz, and the noise level depends on whether the noise level is 20 dB or less. The pass / fail of the measurement test was judged. The target value of 20 dB is determined based on the noise level at which the noise is apparently small in the noise measurement test.

FIG. 4 shows the test results of the produced case-contained type magnetic cores. First, the entire laminated end surface of the magnetic core (A = 790
When comparing the experimental results of Sample 6, Sample 8, and Sample 9 in which different adhesives are applied to mm ² , the noise level is
Sample 6 and Sample 8 in this order, that is, the Young's modulus of the adhesive used (silicone gel: Young's modulus E = 1.3 × 10 ⁴ N
/ M ² , fluid silicone rubber: E = 1.0 × 10 ⁷ N /
m ² and epoxy adhesive: E = 3.0 × 10 ⁹ N / m ² ) in that order, and sample 9 using sill cone gel
It turns out that only those who have passed the noise measurement test. However, Sample 9 has failed the fixation test,
These three samples are case-holding type magnetic cores that have low reliability as magnetic parts or generate a large amount of noise.

Samples 1 to 6 in which fluid silicone rubber was used as the adhesive and the total adhesive area A was different
From the results of the experiment, it was confirmed that the noise level and the total adhesive area A have a positive correlation, and if the total adhesive area A is 90 mm ² (Sample 5) or less, the noise level is the target. It can be seen that the value is below 20 dB.

Thus, from the results of this experiment, the noise level of the case-housing type magnetic core is correlated with the Young's modulus E of the adhesive used and the total adhesive area A of the adhesive (the correlation coefficient is positive). ) It is understood that it is something to do. Therefore, the present inventors set AE / E as a parameter including both A and E.
(M · d) was selected, and the noise level of each sample was tried to be organized by this parameter. Here, m is the mass of the magnetic core, d is the average gap length between the case and the magnetic core when the magnetic core is housed in the case (that is, the average thickness of the adhesive provided between the case and the magnetic core), and FIG. In each sample shown in FIG. 4, m = 30 × 10 ⁻³ [kg], d = 0.3 × 10
^-3 [m]. In addition, A ・ E / (m ・ d) is
It is a parameter that is a coefficient of the equation of motion of a system in which an object having a mass m is fixed by an elastic body having a Young's modulus E, an area A, and a length d.

FIG. 5 shows the noise level of each sample and AE /
The relationship with (m · d) is shown. As is clear from this figure, a strong positive correlation is recognized between the noise level and A · E / (m · d), and A · E / (m · d) is 1.0.
If it is not more than × 10 ⁸ , the noise level of the case-housing type magnetic core is below the target value of 20 dB.

Although detailed description is omitted, m and d are
We have also manufactured and evaluated a case storage type magnetic core that has been changed.
, The noise measurement result of the sample even when m and d are changed
Between the noise level and A / E / (m / d) shown in FIG.
It has been confirmed that it is on the characteristic curve. Give an example
For example, using fluid silicone rubber, d = 1.0 × 10
^-3[M], A = 27 [mm²] A sample (A / E /
(M · d) = 9 × 10⁶) Noise level is 17 dB
This measurement result is on the characteristic curve of Fig. 5.
Has become.

As described above, A · E / (m · d) can be used as an index of the noise level of the case-storing type magnetic core, and A · E / (m · d) ≦ 1.0 × 10 ⁸ As long as the above condition is satisfied, a case-storage type magnetic core that produces less noise during use can be obtained.

However, as described with reference to FIG.
・ Sample 9 with E / (m · d) of 1.1 × 10 ⁶ failed the fixing test, and A / E / (m · d)>
The fact that 1.1 × 10 ⁶ is satisfied is a necessary condition for giving a high reliability as a magnetic component to the case-housing type magnetic core. However, as is clear from the existence of the experimental results regarding Sample 1, for that purpose, A · E / (m ·
d) ≧ 3.0 × 10 ⁶ is established, and eventually 3.0 × 10 ⁶ ≦ A · E / (m · d) ≦
If 1.0 × 10 ⁸ is satisfied, a case-storage type magnetic core that passes both the fixing test and the noise measurement test can be obtained.

[0029]

As described above in detail, according to the present invention, it is possible to prevent both the movement of the magnetic core within the case and the propagation of the vibration of the magnetic core to the case. It is possible to obtain a case-storage type magnetic core which is highly reliable and generates less noise during use.

[Brief description of drawings]

FIG. 1 is an assembly diagram showing a configuration of a case-housing type magnetic core of the present invention.

FIG. 2 is an explanatory diagram showing an outline of a noise measurement test of a case-housing type magnetic core.

FIG. 3 is a block diagram showing an outline of an excitation circuit used in a noise measurement test.

FIG. 4 is a diagram showing test results for each case storage type magnetic core.

FIG. 5 shows the noise level of each case storage type magnetic core as AE / md.
Is a graph plotted against.

[Explanation of symbols]

 10 Case Storage Type Magnetic Core 11 Magnetic Core 12 Case 13 Adhesive 15 Coil 21 Microphone 22 Signal Generator 23 Power Amplifier 24 Current Source

Claims (3)

[Claims] 1. A case storage type magnetic core in which a magnetic core is fixed to a case in which the magnetic core is stored by using an adhesive, wherein the mass of the magnetic core is m [kg], and the Young's modulus after curing of the adhesive. E [N / m ² ], the total thickness of the adhesive provided in the gap between the magnetic core end surface and the case is d [m], and the total adhesive area between the magnetic core end surface and the case by the adhesive. Is defined as A [m ² ], the case storage type magnetic core is formed so as to satisfy the relationship of 3 × 10 ⁶ ≦ AE · (m · d) ≦ 1 × 10 ⁸ . 2. The case-holding type magnetic core according to claim 1, wherein the case has a closed structure. 3. The case-housing type magnetic core according to claim 1, wherein the magnetic core is made of an amorphous magnetic alloy ribbon.