JP3678479B2 - Low temperature coefficient ferrite core and electronic components - Google Patents
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Description
【０００１】
【発明の属する技術分野】
本発明は、広い温度範囲で初透磁率（以下、μｉと称す）の変化率が極めて小さく、照明用トランス、通信機用トランス、またはノイズフィルター等に使用するのに適した低温度係数フェライト磁心に関するものであり、また照明機器、通信機器、受信機器に組み込まれる電子部品に関するものである。
【０００２】
【従来の技術】
照明機器、通信機器、受信機器等の電子部品の磁心として用いられるＭｎ−Ｚｎ系フェライトには、高透磁率、高飽和磁束密度、低損失等の磁気特性であることが要求される。
最近では、これに加えて環境温度の変化に対して安定した磁気特性を得るため、温度特性が優れたものが必要とされている。
【０００３】
これまで、主成分組成の限定や酸化コバルトの添加により、初透磁率温度係数を改良した報告（特公昭５２−３１５５５、特公昭６１−１１８９２など）がある。
しかしながら、高飽和磁束密度、低損失といった他の磁気特性を考慮したり、酸化コバルトの添加量が増すことによりμｉが低下し、μｉが１，０００以下であるものが多く、高いものでもμｉは２，０００程度であった。
また、主成分組成に関しても、例えばＺｎＯの場合１６モル％以下に設定されることが多い。このため、キュリー温度が高く、μｉの温度特性のカーブが大きなうねりをもち、結果的にμｉの変化率が大きくなった。
【０００４】
一方、広い温度範囲でμｉの変化率が小さいことの要求に対しては、高透磁率よりもμｉの変化率が小さいことが重要視されることから、磁心の磁路に空隙を設けた形状とすることが多かった。
【０００５】
【発明が解決しようとする課題】
Ｍｎ−Ｚｎ系フェライト磁心には、電子部品の小型化に伴う高透磁率化、温度安定性向上に伴うμｉ変化率の低下が望まれている。
例えば、照明用トランスに用いる場合、μｉ変化率の大きな磁心では、環境温度の変化が厳しい条件下でインダクタンスの低下に伴い、照明機器の点灯不良などの不具合が生じていた。このため、μｉの変化率を抑制する目的として磁心に空隙を設けられており、これによる透磁率の低下が問題であった。
さらに、磁心に空隙を設けるために磁心を加工すること、また空隙を形成するために磁心の突き合わせ面にポリエステルフィルムを挿入することが必要であり、加工工数および組立に必要な部品等による工数、コストの増加も否めなかった。
一方、ノイズフィルター用磁心においても、環境温度の変化によってノイズ減衰量が異なるため、温度特性の改善が必要とされていた。
本発明は、上記の事を鑑みて、μｉが大きく、μｉの温度特性に優れた低温度係数フェライト磁心とこれを用いた電子部品を提供するものである。
【０００６】
【課題を解決するための手段】
第１の発明は、Ｆｅ２Ｏ３：５３〜５４モル％、ＺｎＯ：１６〜２２モル％、残部ＭｎＯを主成分とし、副成分として、ＳｉＯ２、ＣａＯを含有し、更に、ＣｏＯを０．０５〜０．１０ｗｔ％含有し、２０℃における初透磁率が２５００以上であり、２０℃の初透磁率を基準とした−２０〜６０℃における初透磁率の変化率が−８．１％〜＋９．３％である低温度係数フェライト磁心である。
本発明の低温度係数フェライト磁心においては、更に副成分としてＢｉ２Ｏ３、Ｎｂ２Ｏ５のどちらかを含み、前記Ｂｉ ２ Ｏ ３ が０．０２ｗｔ％〜０．０４ｗｔ％、前記Ｎｂ ２ Ｏ ５ が０．０２ｗｔ％であるのが好ましい。
第２の発明は、第１の発明の低温度係数フェライト磁心を組み込んで構成する電子部品である。前記電子部品としては、特に照明用トランス又は通信機用トランス又はノイズフィルタとして用いるのが好ましい。
【０００９】
【発明の実施の形態】
本発明において、主成分組成を限定した理由は、Ｆｅ2Ｏ3が５３モル％未満、または５４モル％を越える組成領域、およびＺｎＯが１６モル％未満、または２２モル％を越える組成領域では、μｉの温度特性でのセカンダリーピークを−２０〜１０℃、もしくは−１０〜０℃に設定し、かつμｉが２，５００以上のフェライト磁心を得ることが困難なためである。
【００１０】
本発明において、μｉの温度特性でのセカンダリーピークを−２０〜１０℃、もしくは−１０〜０℃に設定する必要がある理由は、セカンダリーピークが上記の範囲より低温側に外れると、μｉの温度特性のカーブが大きなうねりをもち、２０℃におけるμｉが低く、かつμｉの変化率が大きくなるためである。一方、セカンダリーピークが上記の範囲より高温側に外れると、特に２０℃以下の低温度範囲でのμｉの変化率が大きくなり、望ましくないからである。
【００１１】
従来の低温度係数フェライト磁心ではμｉが１，０００以下であるものが多く、高いものでもμｉは２，０００程度であった。しかし本発明により、μｉが２，５００〜５，０００を有し、２０℃のμｉを基準とした−２０〜６０℃におけるμｉの変化率を−８．１％〜＋９．３％とすることにより、温度特性に優れた低温度係数フェライト磁心の小型化が可能になった。
【００１２】
また、従来の低温度係数フェライト磁心では主成分組成に関しても、例えばＺｎＯの場合、１６モル％以下に設定されることが多かった。これに対して、１６〜２２モル％に限定することで、μｉの低下を抑えて、かつμｉの温度特性でカーブのうねりが少ない温度特性に優れた低温度係数フェライト磁心が得られるものである。
【００１３】
本発明はμｉの温度特性で，セカンダリーピークを−２０〜１０℃に設定することで、広い温度範囲でμｉの変化率が小さい低温度係数フェライト磁心が得られるものである。
【００１４】
本発明は上記のように広い温度範囲でμｉの変化率が小さい低温度係数フェライト磁心を使用することにより、環境温度が変化しても本来の性能を発揮する照明用トランス、通信機用トランス、ノイズフィルター等の電子部品が得られるものである。
【００１５】
本発明はμｉが２，５００〜５，０００を有し、２０℃のμｉを基準とした−２０〜１００℃におけるμｉの変化率が±１０％以下とする、さらにはμｉが２，５００〜５，０００を有し、２０℃のμｉを基準とした−２０〜６０℃におけるμｉの変化率が±５％以下とすることにより、空隙を設けないフェライト磁心を組み込んだ照明用トランス、通信機用トランス、ノイズフィルター等の電子部品を構成することができるものである。
【００１６】
以下に、本発明に係わるフェライト材料の実施例を詳細に説明する。
実施例１
Ｆｅ2Ｏ3，ＭｎＯ(Ｍｎ3Ｏ4を使用)、ＺｎＯを表１に示すような主成分組成をもつ原料を混合し、これを空気中において８５０℃で２時間仮焼した。これに、ＳｉＯ2 ０．０２ｗｔ％、ＣａＯ（ＣａＣＯ3を使用） ０．０８ｗｔ％、Ｂｉ2Ｏ3 ０．０２ｗｔ％、ＣｏＯ ０．０５ｗｔ％を含有するように添加し、さらに所定量のイオン交換水および分散剤を添加した後、アトライタにて１時間混合粉砕した。これに原料に対して１ｗｔ％のバインダ（ポリビニルアルコール）を加え、スプレードライヤにて造粒し、整粒した顆粒を乾式圧縮成型機と金型を用いて、トロイダル状に成形圧２ｔｏｎ／ｃｍ2で成形した。この成形体を焼成温度１３００℃、酸素分圧５％で焼成し、得られた磁心のμｉの変化率、２０℃におけるμｉ、１００ｋＨｚにおけるｔａｎδ／μｉ、セカンダリーピーク(Ｔｓ)を測定した。この結果を表１に示す。
なお、表１の備考欄に本発明の範囲のものは、実施例とし、本発明の範囲外のものは比較例とした。
また、試料Ｎｏ.３(実施例)、試料Ｎｏ.１４(実施例)、および試料Ｎｏ.１３(比較例)のμｉの温度特性を図１に示す。この表１及び図１から、本発明の実施例は、μｉが２，５００以上と大きく、しかもμｉの温度変化率が極めて小さいことがわかる。また、このとき、Ｆｅ2Ｏ3が５３〜５４モル％、ＺｎＯが１６〜２２モル％、残部酸化マンガンであることが望ましいことがわかる。
【００１７】
【表１】
実施例２
Ｆｅ２Ｏ３ ５３．５ｍｏｌ％、ＭｎＯ（Ｍｎ３Ｏ４を使用） ２８．０ｍｏｌ％、およびＺｎＯ １８．５ｍｏｌ％を主成分とする原料を混合し、これを空気中において８５０℃で２時間仮焼した。これに、ＳｉＯ２ ０．０２ｗｔ％、ＣａＯ（ＣａＣＯ３を使用）０．０８ｗｔ％と、Ｂｉ２Ｏ３、ＣｏＯを表２に示す分量含有するように添加し、さらに所定量のイオン交換水および分散剤を添加した後、アトライタにて１時間混合粉砕した。これに原料に対して１ｗｔ％のバインダ（ポリビニルアルコール）を加え、スプレードライヤにて造粒し、整粒した顆粒を乾式圧縮成型機と金型を用いて、トロイダル状に成形圧２ｔｏｎ／ｃｍ２で成形した。この成形体を焼成温度１３００℃、酸素分圧５％で焼成し、表１と同様、得られた磁心のμｉの変化率、２０℃におけるμｉ、１００ｋＨｚにおけるｔａｎδ／μｉ、セカンダリーピーク（Ｔｓ）を測定した。この結果を表２に示す。この表２から、本発明の実施例は、μｉが２，５００以上と大きく、しかもμｉの温度変化率が極めて小さいことがわかる。
【００１９】
【表２】
実施例３
Ｆｅ２Ｏ３ ５３．５ｍｏｌ％、ＭｎＯ（Ｍｎ３Ｏ４を使用） ２８．０ｍｏｌ％、およびＺｎＯ １８．５ｍｏｌ％を主成分とする原料を混合し、これを空気中において８５０℃で２時間仮焼した。これに、ＳｉＯ２ ０．０２ｗｔ％、ＣａＯ（ＣａＣＯ３を使用）０．０８ｗｔ％と、ＣｏＯ、Ｎｂ２Ｏ５を表３に示す分量含有するように添加し、さらに所定量のイオン交換水および分散剤を添加した後、アトライタにて１時間混合粉砕した。これに原料に対して１ｗｔ％のバインダ（ポリビニルアルコール）を加え、スプレードライヤにて造粒し、整粒した顆粒を乾式圧縮成型機と金型を用いて、トロイダル状に成形圧２ｔｏｎ／ｃｍ２で成形した。この成形体を焼成温度１２５０℃、酸素分圧１％で焼成し、表１と同様、得られた磁心のμｉの変化率、２０℃におけるμｉ、１００ｋＨｚにおけるｔａｎδ／μｉ、セカンダリーピーク（Ｔｓ）を測定した。この結果を表３に示す。この表３から、本発明の実施例は、μｉが２，５００以上と大きく、しかもμｉの温度変化率が極めて小さいことがわかる。
【００２１】
【表３】
以上の実施例では、μｉが２，５００〜５，０００を有し、２０℃のμｉを基準とした−２０〜６０℃におけるμｉの変化率が−８．１〜＋９．３％で、μｉのセカンダリーピークを−２０〜１０℃とした実施例がわかる。また、これらの実施例は、μｉが２，５００以上と大きく、しかもμｉの温度変化率が極めて小さいため、照明用トランス、通信機用トランス、およびノイズフィルター等に使用するのに適した磁心であることがわかる。また、これらの磁心は、例えばＥＥ型磁心と呼ばれるように、２つの磁心を突き合わせて構成されることがあるが、この場合、μｉの温度変化率が極めて小さいため、その磁心の突き合わせ面に空隙を形成して、温度変化を緩和させる手段を用いる必要がない。すなわち、磁心に空隙を形成することなく使用出来る。このため、高い透磁率をそのまま活用出来、しかも空隙を設けるための工数及び部品も必要ない。また、高透磁率を利用し、部品の小型化も達成される。もちろん、磁心の形状は、ＥＥ型に限定されるものではない。例えば、リング型、ＵＵ型、壺型など種々の形状が考えられる。
【００２５】
【発明の効果】
本発明によれば、μｉが２，５００以上と大きく、しかも広い温度範囲でμｉの変化率が小さい低温度係数フェライト磁心を得ることができる。
本発明に係わる低温度係数フェライト磁心を組み込んで構成することにより、環境温度が変化しても本来の性能を発揮する照明用トランス、通信機用トランス、ノイズフィルター等の電子部品が得ることができる。このため、照明機器の点灯不良などの不具合や不安定なノイズ減衰量を生じる恐れがない。
本発明に係わる低温度係数フェライト磁心を組み込んで電子部品を構成する場合、磁心にμｉの変化率を抑制するための空隙を設ける必要がなく、空隙を設けるための加工、空隙を形成するためのポリエステルフィルム、および組立に必要な部品等による工数、コストを削減できる。
【図面の簡単な説明】
【図１】 本発明に係わる実施例と比較例のμｉの温度特性である。[0001]
BACKGROUND OF THE INVENTION
The present invention has a very low rate of change of initial permeability (hereinafter referred to as μi) over a wide temperature range, and is a low temperature coefficient ferrite core suitable for use in an illumination transformer, a communication transformer, a noise filter, or the like. In addition, the present invention relates to electronic components incorporated in lighting equipment, communication equipment, and receiving equipment.
[0002]
[Prior art]
The Mn—Zn ferrite used as the magnetic core of electronic parts such as lighting equipment, communication equipment, and receiving equipment is required to have magnetic properties such as high magnetic permeability, high saturation magnetic flux density, and low loss.
Recently, in addition to this, in order to obtain stable magnetic characteristics against changes in environmental temperature, those having excellent temperature characteristics are required.
[0003]
So far, there have been reports of improving the initial permeability temperature coefficient by limiting the main component composition and adding cobalt oxide (JP-B-52-31555, JP-B-61-11892, etc.).
However, in consideration of other magnetic characteristics such as high saturation magnetic flux density and low loss, or when the addition amount of cobalt oxide is increased, μi decreases, and μi is often 1,000 or less. It was about 2,000.
The main component composition is often set to 16 mol% or less in the case of ZnO, for example. For this reason, the Curie temperature was high, the temperature characteristic curve of μi had a large undulation, and as a result, the rate of change of μi increased.
[0004]
On the other hand, for the requirement that the rate of change of μi is small over a wide temperature range, it is important that the rate of change of μi is smaller than the high magnetic permeability, so that a shape in which a gap is provided in the magnetic path of the magnetic core And often.
[0005]
[Problems to be solved by the invention]
The Mn—Zn based ferrite magnetic core is desired to have a high magnetic permeability accompanying downsizing of electronic parts and a decrease in μi change rate accompanying an improvement in temperature stability.
For example, when used in a transformer for lighting, a magnetic core having a large μi change rate has caused problems such as lighting failure of lighting equipment due to a decrease in inductance under a severe change in environmental temperature. For this reason, a gap is provided in the magnetic core for the purpose of suppressing the rate of change of μi, and a decrease in magnetic permeability due to this is a problem.
Furthermore, it is necessary to process the magnetic core to provide a gap in the magnetic core, and to insert a polyester film into the abutting surface of the magnetic core to form a gap. The increase in cost could not be denied.
On the other hand, in the noise filter magnetic core, since the amount of noise attenuation varies depending on the environmental temperature, it is necessary to improve the temperature characteristics.
In view of the above, the present invention provides a low temperature coefficient ferrite core having a large μi and excellent μi temperature characteristics, and an electronic component using the same.
[0006]
[Means for Solving the Problems]
The first invention, Fe 2 O 3: 53~54 mol%, ZnO: 16 to 22 mol%, as a main component and the remainder MnO, as a sub-component, containing SiO 2, CaO, further, 0 to CoO. containing 05～0.10Wt%, and the initial permeability at 20 ° C. is 2500 or higher, the rate of change of initial permeability at -20 to 60 ° C. relative to the initial permeability of 20 ° C. is -8.1% A low temperature coefficient ferrite core of + 9.3% .
At low temperature coefficient ferrite core of the present invention, further seen contains either Bi 2 O 3, Nb 2 O 5 as an auxiliary component, the Bi 2 O 3 is 0.02wt% ~0.04wt%, the Nb 2 O 5 is preferably 0.02 wt% .
The second invention is an electronic component constructed by incorporating the low temperature coefficient ferrite core of the first invention. The electronic component is particularly preferably used as a lighting transformer, a communication transformer, or a noise filter.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
In the present invention, the reason why the main component composition is limited is that in the composition region where Fe 2 O 3 is less than 53 mol% or more than 54 mol%, and in the composition region where ZnO is less than 16 mol% or more than 22 mol%, This is because it is difficult to set a secondary peak in the temperature characteristic of μi to −20 to 10 ° C. or −10 to 0 ° C. and to obtain a ferrite magnetic core having μi of 2,500 or more.
[0010]
In the present invention, the reason why it is necessary to set the secondary peak in the temperature characteristic of μi to −20 to 10 ° C. or −10 to 0 ° C. is that when the secondary peak deviates to a lower temperature side than the above range, the temperature of μi This is because the characteristic curve has a large undulation, μi at 20 ° C. is low, and the rate of change of μi is large. On the other hand, if the secondary peak deviates from the above range to the high temperature side, the rate of change of μi is particularly large in a low temperature range of 20 ° C. or less, which is not desirable.
[0011]
Many conventional low temperature coefficient ferrite cores have μi of 1,000 or less, and even high ones have μi of about 2,000. However, according to the present invention, μi has 2,500 to 5,000, and the change rate of μi at −20 to 60 ° C. based on μi at 20 ° C. is set to −8.1% to + 9.3%. As a result, it is possible to reduce the size of the low temperature coefficient ferrite core having excellent temperature characteristics.
[0012]
In the conventional low temperature coefficient ferrite core, the main component composition is often set to 16 mol% or less in the case of ZnO, for example. On the other hand, by limiting the amount to 16 to 22 mol%, a low temperature coefficient ferrite core that suppresses the decrease in μi and is excellent in temperature characteristics with less temperature undulation in the μi temperature characteristics can be obtained. .
[0013]
The present invention has a temperature characteristic of μi, and by setting the secondary peak to −20 to 10 ° C., a low temperature coefficient ferrite core having a small change rate of μi can be obtained in a wide temperature range.
[0014]
The present invention uses a low temperature coefficient ferrite magnetic core with a small rate of change of μi in a wide temperature range as described above, so that an illumination transformer, a communication device transformer, which exhibits original performance even when the environmental temperature changes, An electronic component such as a noise filter can be obtained.
[0015]
In the present invention, μi is 2,500 to 5,000, and the change rate of μi at −20 to 100 ° C. with reference to μi at 20 ° C. is ± 10% or less. Furthermore, μi is 2,500 to Transformer for illumination and communication device incorporating a ferrite magnetic core having no gap by having a change rate of μi at −20 to 60 ° C. within ± 5,000% with reference to μi at 20 ° C. Electronic components such as transformers and noise filters can be configured.
[0016]
Below, the example of the ferrite material concerning the present invention is described in detail.
Example 1
Fe 2 O 3 , MnO (using Mn 3 O 4 ) and ZnO were mixed with raw materials having the main component composition as shown in Table 1, and calcined at 850 ° C. for 2 hours in air. To this, 0.02 wt% of SiO 2 , 0.08 wt% of CaO (using CaCO 3 ), 0.02 wt% of Bi 2 O 3 and 0.05 wt% of CoO are added, and a predetermined amount of ion exchange is added. After adding water and a dispersant, the mixture was pulverized for 1 hour using an attritor. A 1 wt% binder (polyvinyl alcohol) is added to the raw material, the mixture is granulated with a spray dryer, and the granulated granule is formed into a toroidal molding pressure of 2 ton / cm 2 using a dry compression molding machine and a mold. Molded with This molded body was fired at a firing temperature of 1300 ° C. and an oxygen partial pressure of 5%, and the change rate of μi of the obtained magnetic core, μi at 20 ° C., tan δ / μi at 100 kHz, and secondary peak (Ts) were measured. The results are shown in Table 1.
In the remarks column of Table 1, those within the scope of the present invention are examples, and those outside the scope of the present invention are comparative examples.
Further, the temperature characteristics of μi of Sample No. 3 (Example), Sample No. 14 (Example), and Sample No. 13 (Comparative Example) are shown in FIG. From Table 1 and FIG. 1, it can be seen that in the example of the present invention, μi is as large as 2,500 or more, and the temperature change rate of μi is extremely small. At this time, Fe 2 O 3 is 53-54 mol%, ZnO is 16 to 22 mol%, it can be seen that it is desirable that the balance of manganese oxide.
[0017]
[Table 1]
Example 2
A raw material mainly composed of 53.5 mol% Fe 2 O 3, 28.0 mol% MnO (using Mn 3 O 4 ), and 18.5 mol% ZnO was mixed, and this was temporarily mixed in air at 850 ° C. for 2 hours. Baked. To this, SiO 2 0.02 wt%, CaO (using CaCO 3 ) 0.08 wt%, Bi 2 O 3 and CoO were added so as to contain the amounts shown in Table 2, and a predetermined amount of ion-exchanged water and After adding the dispersant, the mixture was pulverized with an attritor for 1 hour. A 1 wt% binder (polyvinyl alcohol) is added to the raw material, the mixture is granulated with a spray dryer, and the granulated granules are formed into a toroidal shape with a molding pressure of 2 ton / cm 2 using a dry compression molding machine and a mold. Molded with This molded body was fired at a firing temperature of 1300 ° C. and an oxygen partial pressure of 5%, and as in Table 1, the change rate of μi of the obtained magnetic core, μi at 20 ° C., tan δ / μi at 100 kHz, secondary peak (Ts) It was measured. The results are shown in Table 2. From Table 2, it can be seen that in the examples of the present invention, μi is as large as 2,500 or more and the temperature change rate of μi is extremely small.
[0019]
[Table 2]
Example 3
A raw material mainly composed of 53.5 mol% Fe 2 O 3, 28.0 mol% MnO (using Mn 3 O 4 ), and 18.5 mol% ZnO was mixed, and this was temporarily mixed in air at 850 ° C. for 2 hours. Baked. To this, SiO 2 0.02 wt%, CaO (using CaCO 3 ) 0.08 wt%, CoO, and Nb 2 O 5 were added so as to contain the amounts shown in Table 3, and a predetermined amount of ion-exchanged water and After adding the dispersant, the mixture was pulverized with an attritor for 1 hour. A 1 wt% binder (polyvinyl alcohol) is added to the raw material, the mixture is granulated with a spray dryer, and the granulated granules are formed into a toroidal shape with a molding pressure of 2 ton / cm 2 using a dry compression molding machine and a mold. Molded with This molded body was fired at a firing temperature of 1250 ° C. and an oxygen partial pressure of 1%, and as in Table 1, the change rate of μi of the obtained magnetic core, μi at 20 ° C., tan δ / μi at 100 kHz, secondary peak (Ts) It was measured. The results are shown in Table 3. From Table 3, it can be seen that in the examples of the present invention, μi is as large as 2500 or more, and the temperature change rate of μi is extremely small.
[0021]
[Table 3]
In the above example, μi has 2,500 to 5,000, and the change rate of μi at −20 to 60 ° C. with respect to μi at 20 ° C. is −8.1 to + 9.3% . The example which made the secondary peak of -20-10 degreeC is understood. In addition, these embodiments have a magnetic core suitable for use in lighting transformers, communication transformers, noise filters, and the like because μi is as large as 2,500 or more and the temperature change rate of μi is extremely small. I know that there is. In addition, these magnetic cores may be configured by abutting two magnetic cores, for example, called an EE type magnetic core. In this case, since the temperature change rate of μi is extremely small, there is a gap in the abutting surface of the magnetic core. It is not necessary to use a means for reducing the temperature change by forming the. That is, it can be used without forming voids in the magnetic core. For this reason, high magnetic permeability can be utilized as it is, and man-hours and parts for providing a gap are not required. In addition, miniaturization of parts can be achieved by utilizing high magnetic permeability. Of course, the shape of the magnetic core is not limited to the EE type. For example, various shapes such as a ring shape, a UU shape, and a saddle shape are conceivable.
[0025]
【The invention's effect】
According to the present invention, it is possible to obtain a low temperature coefficient ferrite core having a large μi of 2500 or more and a small change rate of μi in a wide temperature range.
By incorporating the low temperature coefficient ferrite core according to the present invention, it is possible to obtain electronic parts such as a lighting transformer, a communication transformer, and a noise filter that exhibit their original performance even when the environmental temperature changes. . For this reason, there is no possibility of causing problems such as lighting failure of the lighting device and unstable noise attenuation.
When an electronic component is constructed by incorporating a low temperature coefficient ferrite core according to the present invention, it is not necessary to provide a gap for suppressing the change rate of μi in the magnetic core, and processing for providing a gap, for forming a gap Man-hours and costs due to polyester film and parts required for assembly can be reduced.
[Brief description of the drawings]
FIG. 1 is a temperature characteristic of μi of an example according to the present invention and a comparative example.
Claims (4)
更に、ＣｏＯを０．０５〜０．１０ｗｔ％含有し、
２０℃における初透磁率が２５００以上であり、２０℃の初透磁率を基準とした−２０〜６０℃における初透磁率の変化率が−８．１％〜＋９．３％であることを特徴とする低温度係数フェライト磁心。Fe 2 O 3 : 53 to 54 mol%, ZnO: 16 to 22 mol%, the balance being MnO as a main component, and SiO 2 and CaO as subcomponents ,
Furthermore, it contains 0.05 to 0.10 wt% CoO,
The initial permeability at 20 ° C. is 2500 or more, and the change rate of the initial permeability at −20 to 60 ° C. based on the initial permeability at 20 ° C. is −8.1% to + 9.3%. Low temperature coefficient ferrite core.
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| Application Number | Priority Date | Filing Date | Title |
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| JP30895595A JP3678479B2 (en) | 1995-11-28 | 1995-11-28 | Low temperature coefficient ferrite core and electronic components |
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| JP30895595A JP3678479B2 (en) | 1995-11-28 | 1995-11-28 | Low temperature coefficient ferrite core and electronic components |
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| JP2002088141A Division JP2002353024A (en) | 2002-03-27 | 2002-03-27 | Ferrite magnetic core having low-temperature coefficient, and electronic component |
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| JPH09148115A JPH09148115A (en) | 1997-06-06 |
| JP3678479B2 true JP3678479B2 (en) | 2005-08-03 |
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