JP4369008B2

JP4369008B2 - Alloy type temperature fuse

Info

Publication number: JP4369008B2
Application number: JP2000105933A
Authority: JP
Inventors: 嘉明田中
Original assignee: Uchihashi Estec Co Ltd
Current assignee: Uchihashi Estec Co Ltd
Priority date: 2000-04-07
Filing date: 2000-04-07
Publication date: 2009-11-18
Anticipated expiration: 2020-04-07
Also published as: JP2001291459A

Description

【産業上の利用分野】
【０００１】
本発明は、作動温度が６５℃〜７５℃の合金型温度ヒュ−ズに関するものである。
【従来の技術】
【０００２】
合金型温度ヒュ−ズにおいては、フラックスを塗布した低融点可溶合金片をヒュ−ズエレメントとしており、保護すべき電気機器に取り付けて使用され、電気機器がその異常時に発熱すると、その発生熱により低融点可溶合金片が液相化され、その溶融金属がフラックスとの共存下、表面張力により球状化され、球状化の進行により分断されて機器への通電が遮断される。
【０００３】
上記低融点可溶合金に要求される要件の一つは、固相線と液相線との間の固液共存域が狭いことである。
すなわち、通常、合金においては、固相線と液相線との間に固液共存域が存在し、この領域においては、液相中に固相粒体が分散した状態にあり、液相様の性質も備えているために、上記の球状化分断が発生する可能性があり、従って、液相線温度（この温度をＴとする）以前に固液共存域に属する温度範囲（ΔＴとする）で、低融点可溶合金片が球状化分断される可能性がある。而して、かかる低融点可溶合金片を用いた温度ヒュ−ズにおいては、ヒュ−ズエレメント温度が（Ｔ−ΔＴ）〜Ｔとなる温度範囲で動作するものとして取り扱わなければならず、従って、ΔＴが小であるほど、すなわち、固液共存域が狭いほど、温度ヒュ−ズの作動温度範囲のバラツキを小として、温度ヒュ−ズを所定の設定温度で作動させることができる。従って、温度ヒュ−ズのヒュ−ズエレメントとして使用される合金には、固液共存域が狭いことが要求される。
【０００４】
更に、上記低融点可溶合金に要求される要件の一つは、電気抵抗が低いことである。
すなわち、低融点可溶合金片の抵抗に基づく平常時の発熱による温度上昇をΔＴ’とすると、その温度上昇がないときに較べ、実質上、作動温度がΔＴ’だけ低くなり、ΔＴ’が高くなるほど、作動誤差が実質的に高くなる。従って、温度ヒュ−ズのヒュ−ズエレメントとして使用される合金には、比抵抗が低いことが要求される。
【０００５】
【発明が解決しようとする課題】
従来、作動温度６５℃〜７５℃の合金型温度ヒュ−ズのヒュ−ズエレメントとしては、７０℃共晶のＢｉ−Ｐｂ−Ｓｎ−Ｃｄ合金（Ｂｉ５０重量％，Ｐｂ２６．７重量％，Ｓｎ１３．３重量％，Ｃｄ１０重量％）が知られているが、生体系に有害なＰｂやＣｄを含有しており、近来の地球規模での要請である環境保全上から不適格である。また、近来の電気・電子機器の小型化に対応しての合金型温度ヒュ−ズの小型化に伴う、ヒュ−ズエレメントの極細線化（３００μｍ）には、Ｂｉの含有量が多く脆弱であるためにかかる極細線の線引き加工が困難であって、対処が困難であり、しかも、かかる極細線ヒュ−ズエレメントのもとでは、その合金組成の比較的高い比抵抗と極細線化とが相俟って、抵抗値が著しく高くなる結果、上記ヒュ−ズエレメントの自己発熱による作動不良が避けられない。
【０００６】
また、７２℃共晶のＩｎ−Ｂｉ合金（Ｉｎ６６．３重量％，Ｂｉ３３．７重量％）も知られているが、図７に示す熱示差曲線から明らかなように、５３℃〜５６℃の間で固相変態を生じ、この温度が作動温度６５℃〜７５℃との相対関係から機器の平常時運転時にヒュ−ズエレメントが長期的に曝される温度であるため、ヒュ−ズエレメントに固相変態に起因して歪が発生し、その結果、ヒュ−ズエレメントの抵抗値が増大し、ヒュ−ズエレメントの自己発熱による作動不良が懸念される。
【０００７】
かかる現況下、本発明者において、作動温度が６５℃〜７５℃の範囲で、有害金属を含有せず、ヒュ−ズエレメント径をほぼ３００μｍφ程度に極細化し得、自己発熱をよく抑えて正確に作動させ得る合金型温度ヒュ−ズを開発すべく鋭意検討したところ、７２℃共晶のＩｎ−Ｂｉ合金にＳｎを２．５〜１０重量％添加することにより、平常時運転時での上記固相変態も排除し得、その目的を達成できることを知った。
【０００８】
本発明の目的は、かかる成果を基礎として、作動温度６５℃〜７５℃の範囲で、環境保全の要請を充足し、ヒュ−ズエレメント径をほぼ３００μｍφ程度に極細化し得、自己発熱をよく抑えて正確に作動させ得る合金型温度ヒュ−ズを提供することにある。
【０００９】
【課題を解決するための手段】
本発明の請求項１に係る合金型温度ヒュ−ズは、低融点可溶合金をヒュ−ズエレメントとする温度ヒュ−ズにおいて、低融点可溶合金の合金組成が、Ｂｉ２５〜３５重量％、Ｓｎ２．５〜１０重量％、残部Ｉｎであることを特徴とする構成である。
【００１０】
本発明の請求項２に係る合金型温度ヒュ−ズは、低融点可溶合金をヒュ−ズエレメントとする温度ヒュ−ズにおいて、低融点可溶合金の合金組成が、Ｂｉ２５〜３５重量％、Ｓｎ２．５〜１０重量％、残部Ｉｎの１００重量部にＡｇが０．５〜３．５重量部添加された組成であることを特徴とする構成であり、Ａｇの添加により、比抵抗を低減できると共に動作温度を殆ど変えずに固液共存領域の巾を狭めて作動温度のバラツキをより一層に抑制できる。
【００１１】
【発明の実施の形態】
本発明に係る合金型温度ヒュ−ズにおいて、ヒュ−ズエレメントには、外径２００μｍφ〜５００μｍφ、好ましくは２５０μｍφ〜３５０μｍφの円形線、または当該円形線と同一断面積の扁平線を使用できる。
【００１２】
このヒュ−ズエレメントの合金は、Ｂｉ２５〜３５重量％、Ｓｎ２．５〜１０重量％、残部Ｉｎ、好ましくは、Ｂｉ２９〜３３重量％、Ｓｎ３〜６重量％、残部Ｉｎあり、基準組成は、Ｂｉ３２．７重量％，Ｓｎ３．８重量％，Ｉｎ６３．５重量％であり，その液相線温度は７１℃，固液共存域巾は３℃である。
【００１３】
前記配合量のＩｎ及びＢｉにより融点が７０℃付近に仮設定されると共に細線の線引きに必要な充分な延性が与えられ、Ｓｎの配合により固相線温度と液相線温度の範囲が６５℃〜７５℃に最終的に設定されると共に比抵抗が低く設定される。
Ｓｎ配合量の下限が請求項１の配合量未満では、Ｓｎ量が不足して上記の成果を達成し難いばかりか、前記した固相変態を有効に防止し得ず、またＳｎ配合量の上限が請求項１の配合量を越えると、融点６２℃のＩｎ−Ｂｉ−Ｓｎ共晶組成（Ｉｎ４２重量％，Ｂｉ２９重量％，Ｓｎ１３重量％）が出現し、固相線温度と液相線温度の範囲を６５℃〜７５℃におさめ得ないばかりか、溶融ピ−クの二極化による動作温度の顕著なバラツキが避けられない。
この組成では、比抵抗の高いＢｉに対し、比抵抗の低いＩｎ、Ｓｎの総量が多いために全体の比抵抗を充分に低くでき、３００μｍφという極細線のもとでも、ヒュ−ズエレメントの低抵抗を容易に達成でき、図１（Ｉｎ−３２．７Ｂｉ−３．８ＳｎのＤＳＣ測定結果）から明らかなように、作動温度６５℃〜７５℃の低温側に固相変態が発生することがなく、作動温度６５℃〜７５℃に対する機器の平常運転時の温度でのヒュ−ズエレメントの固相変態に起因しての抵抗値変化も排除できるから、温度ヒュ−ズの作動温度を７０℃を基準として±５℃以内の範囲に設定できる。
前記ヒュ−ズエレメントの抵抗率は、２５〜３５μΩ・ｃｍである。
【００１４】
上記合金組成１００重量部にＡｇを０．５〜３．５重量部添加することにより、抵抗率を前記よりも低くすることができ、例えば、３．５重量部添加することにより、１０％程度低くできる。
【００１５】
本発明に係る温度ヒュ−ズのヒュ−ズエレメントは、合金母材の線引きにより製造され、断面丸形のまま、または、さらに扁平に圧縮加工して使用できる。
【００１６】
図２は、本発明に係るテ−プタイプの合金型温度ヒュ−ズを示し、厚み１００〜３００μｍのプラスチックベ−スフィルム４１に厚み１００〜２００μｍの帯状リ−ド導体１，１を接着剤または融着により固着し、帯状リ−ド導体間に線径２５０μｍφ〜５００μｍφのヒュ−ズエレメント２を接続し、このヒュ−ズエレメント２にフラツクス３を塗布し、このフラツクス塗布ヒュ−ズエレメントを厚み１００〜３００μｍのプラスチックカバ−フィルム４１の接着剤または融着による固着で封止してある。
【００１７】
本発明に係る合金型温度ヒュ−ズは、筒型ケ−スタイプ、ケ−ス型ラジアルタイプ、基板タイプ、樹脂モ−ルドラジアルタイプの形式で実施することもできる。
図３は筒型ケ−スタイプを示し、一対のリ−ド線１，１間に低融点可溶合金片２を接続し、該低融点可溶合金片２上にフラックス３を塗布し、このフラックス塗布低融点可溶合金片上に耐熱性・良熱伝導性の絶縁筒４、例えば、セラミックス筒を挿通し、該絶縁筒４の各端と各リ−ド線１との間を常温硬化の接着剤、例えば、エポキシ樹脂で封止してある。
【００１８】
図４はケ−ス型ラジアルタイプを示し、並行リ−ド導体１，１の先端部間にヒュ−ズエレメント２を溶接により接合し、ヒュ−ズエレメント２にフラックス３を塗布し、このフラックス塗布ヒュ−ズエレメントを一端開口の絶縁ケ−ス４、例えばセラミックスケ−スで包囲し、この絶縁ケ−ス４の開口をエポキシ樹脂等の封止材５で封止してある。
【００１９】
図５は基板タイプを示し、絶縁基板４、例えばセラミックス基板上に一対の膜電極１，１を導電ペ−スト（例えば銀ペ−スト）の印刷焼付けにより形成し、各電極１にリ−ド導体１１を溶接等により接続し、電極１，１間にヒュ−ズエレメント２を溶接により接合し、ヒュ−ズエレメント２にフラックス３を塗布し、このフラックス塗布ヒュ−ズエレメントを封止材４例えばエポキシ樹脂で封止してある。
【００２０】
図６は樹脂モ−ルドラジアルタイプを示し、並行リ−ド導体１，１の先端部間にヒュ−ズエレメント２を溶接により接合し、ヒュ−ズエレメント２にフラックス３を塗布し、このフラックス塗布ヒュ−ズエレメントを樹脂液ディッピングにより樹脂モ−ルド５してある。
【００２１】
また、通電式発熱体付きヒュ−ズ、例えば、基板タイプの合金型温度ヒュ−ズの絶縁基板に抵抗体（膜抵抗）を付設し、機器の異常時、抵抗体を通電発熱させ、その発生熱で低融点可溶合金片を溶断させる抵抗付きの基板型ヒュ−ズの形式で実施することもできる。
【００２２】
上記のフラックスには、通常、融点がヒュ−ズエレメントの融点よりも低いものが使用され、例えば、ロジン９０〜６０重量部、ステアリン酸１０〜４０重量部、活性剤０〜３重量部を使用できる。この場合、ロジンには、天然ロジン、変性ロジン（例えば、水添ロジン、不均化ロジン、重合ロジン）またはこれらの精製ロジンを使用でき、活性剤には、ジエチルアミンの塩酸塩や臭化水素酸塩等を使用できる。
【００２３】
【実施例】
〔実施例１〕
Ｉｎ６３．５重量％，Ｂｉ３２．７重量％，Ｓｎ３．８重量％の合金組成の母材を線引きして直径３００μｍφの線に加工した。１ダイスについての引落率を６．５％とし、線引き速度を４５ｍ／ｍｉｎとしたが、断線は皆無であった。
この線の抵抗率を測定したところ、３２μΩ・ｃｍであった。
この線を長さ４ｍｍに切断してヒュ−ズエレメントとし、テ-プタイプの温度ヒュ−ズを作成した。フラックスには、ロジン８０重量部，ステアリン酸２０重量部，ジエチルアミン臭化水素酸塩１重量部の組成物を使用し、プラスチックベ−スフィルム及びプラスチックカバ−フィルムには厚み２００μｍのホリエチレンテレフタレ−トフィルムを使用した。
【００２４】
この実施例品５０箇を、０．１アンペアの電流を通電しつつ、昇温速度１℃／分のオイルバスに浸漬し、溶断による通電遮断時のオイル温度を測定したところ、７１℃±１℃の範囲内であった。通電電流を１／１０にして同様の測定を行ったところ、実質上差は認められず、自己発熱の影響の無いことを確認した。
また、上記した合金組成の範囲内であれば、動作温度を７０℃を中心として±５℃の範囲内に納めることができた。
【００２５】
〔実施例２〕
Ｉｎ６１．３重量％，Ｂｉ３１．６重量％，Ｓｎ３．７重量％，Ａｇ３．４重量％の合金組成の母材を線引きして直径３００μｍφの線に加工した。１ダイスについての引落率を６．５％とし、線引き速度を４５ｍ／ｍｉｎとしたが、断線は皆無であった。この線の抵抗率を測定したところ、２９μΩ・ｃｍであった。
この線を長さ４ｍｍに切断してヒュ−ズエレメントとし、実施例１と同様のテ−プタイプの温度ヒュ−ズを作成した。
【００２６】
この実施例品５０箇を、０．１アンペアの電流を通電しつつ、昇温速度１℃／分のオイルバスに浸漬し、溶断による通電遮断時のオイル温度を測定したところ、７０℃±１℃の範囲内であった。通電電流を１／１０にして同様の測定を行ったところ、実質上差は認められず、自己発熱の影響の無いことを確認した。
また、上記した合金組成の範囲内であれば、動作温度を７０℃を中心として±４℃の範囲内に納めることができた。
【００２７】
〔比較例〕
Ｉｎ６６．３重量％，Ｂｉ３３．７重量％の合金組成の母材を線引きして直径３００μｍφの線に加工した。１ダイスについての引落率を６．５％とし、線引き速度を４５ｍ／ｍｉｎとしたが、断線は皆無であった。
この線の抵抗率を測定したところ、３７μΩ・ｃｍであった。
この線を長さ４ｍｍに切断してヒュ−ズエレメントとし、実施例１と同様にしてテ-プタイプの温度ヒュ−ズを作成し、作動温度を測定したところ、６０℃付近で作動するものから７４℃付近で作動するものが観られ、作動温度に大幅なバラツキが認められた。
これは、低温側での固相変態に起因するものであり、本発明に係る温度ヒュ−ズのヒュ−ズエレメントにおける、Ｓｎを配合したことの意義を確認できた。
【００２８】
【発明の効果】
本発明によれば、生体系に影響のないＢｉ−Ｉｎ−Ｓｎ系の低融点可溶合金母材の能率のよい線引きで３００μｍφクラスの極細線ヒュ−ズエレメントを製造し、このヒュ−ズエレメントを用いて動作温度が６５℃〜７５℃で、かつ自己発熱による作動誤差を充分に防止できる合金型温度ヒュ−ズを得ることができる。
【図面の簡単な説明】
【図１】Ｉｎ−３２．７Ｂｉ−３．８ＳｎのＤＳＣ測定結果を示す図面である。
【図２】本発明に係る合金型温度ヒュ−ズの一例を示す図面である。
【図３】本発明に係る合金型温度ヒュ−ズの上記とは別の例を示す図面である。
【図４】本発明に係る合金型温度ヒュ−ズの上記とは別の例を示す図面である。
【図５】本発明に係る合金型温度ヒュ−ズの上記とは別の例を示す図面である。
【図６】本発明に係る合金型温度ヒュ−ズの上記とは別の例を示す図面である。
【図７】Ｉｎ−３３．７ＢｉのＤＳＣ測定結果を示す図面である。
【符号の説明】
２ヒュ−ズエレメント[Industrial application fields]
[0001]
The present invention relates to an alloy type temperature fuse having an operating temperature of 65 ° C to 75 ° C.
[Prior art]
[0002]
In the alloy type temperature fuse, a low melting point soluble alloy piece coated with a flux is used as a fuse element, and it is used by being attached to an electric device to be protected. As a result, the low-melting-point soluble alloy piece is made into a liquid phase, and the molten metal is spheroidized by surface tension in the presence of the flux, and is divided by the progress of spheronization, and the current supply to the device is cut off.
[0003]
One of the requirements for the low melting point soluble alloy is that the solid-liquid coexistence area between the solid phase line and the liquid phase line is narrow.
That is, in an alloy, there is usually a solid-liquid coexistence zone between the solid phase line and the liquid phase line. In this region, the solid phase particles are dispersed in the liquid phase. Therefore, the above spheroidization may occur. Therefore, the temperature range (ΔT) belonging to the solid-liquid coexistence region before the liquidus temperature (this temperature is T). ), The low melting point soluble alloy piece may be spheroidized. Thus, in the temperature fuse using such a low melting point soluble alloy piece, the fuse element temperature must be handled as operating in a temperature range of (T−ΔT) to T. The smaller the ΔT is, that is, the narrower the solid-liquid coexistence region, the smaller the variation in the operating temperature range of the temperature fuse, and the temperature fuse can be operated at a predetermined set temperature. Therefore, an alloy used as a fuse element for a temperature fuse is required to have a narrow solid-liquid coexistence region.
[0004]
Furthermore, one of the requirements for the low melting point soluble alloy is that the electric resistance is low.
That is, assuming that the temperature rise due to normal heat generation based on the resistance of the low melting point soluble alloy piece is ΔT ′, the operating temperature is substantially lower by ΔT ′ and ΔT ′ is higher than when there is no temperature rise. Indeed, the operating error is substantially increased. Therefore, an alloy used as a fuse element for a temperature fuse is required to have a low specific resistance.
[0005]
[Problems to be solved by the invention]
Conventionally, as a fuse element of an alloy type temperature fuse having an operating temperature of 65 ° C. to 75 ° C., a 70 ° C. eutectic Bi—Pb—Sn—Cd alloy (Bi 50 wt%, Pb 26.7 wt%, Sn13. 3% by weight and Cd 10% by weight) are known, but contain Pb and Cd that are harmful to biological systems, and are unfit for environmental conservation, which is a recent global demand. In addition, due to the miniaturization of the fuse-type temperature fuse corresponding to the miniaturization of recent electrical and electronic equipment, the fuse element has become extremely thin (300 μm), and the Bi content is large and fragile. Therefore, it is difficult to draw such a fine wire, and it is difficult to deal with it, and under such a fine wire fuse element, the alloy composition has a relatively high specific resistance and a fine wire. Combined with this, the resistance value becomes extremely high, so that malfunction of the fuse element due to self-heating is inevitable.
[0006]
A 72 ° C. eutectic In—Bi alloy (In 66.3% by weight, Bi 33.7% by weight) is also known, but as is apparent from the thermal differential curve shown in FIG. Because this phase is a temperature at which the fuse element is exposed for a long time during normal operation of the equipment due to the relative relationship with the operating temperature of 65 ° C to 75 ° C, Distortion occurs due to the solid phase transformation, and as a result, the resistance value of the fuse element increases, and there is a concern about malfunction due to self-heating of the fuse element.
[0007]
Under the present situation, the present inventor can accurately reduce the fuse element diameter to about 300 μmφ without containing harmful metals and with an operating temperature of 65 ° C. to 75 ° C. As a result of diligent research to develop an alloy-type temperature fuse that can be operated, by adding 2.5 to 10% by weight of Sn to a 72 ° C. eutectic In-Bi alloy, I learned that phase transformation could be eliminated and that purpose could be achieved.
[0008]
The purpose of the present invention is based on such results, satisfying environmental protection requirements in the operating temperature range of 65 ° C to 75 ° C, and can reduce the fuse element diameter to about 300 µmφ and suppress self-heating well. It is an object of the present invention to provide an alloy type temperature fuse that can be operated accurately.
[0009]
[Means for Solving the Problems]
An alloy type temperature fuse according to claim 1 of the present invention is a temperature fuse in which a low melting point soluble alloy is a fuse element, and the alloy composition of the low melting point soluble alloy is Bi25 to 35% by weight, The composition is characterized in that Sn is 2.5 to 10% by weight and the balance is In.
[0010]
The alloy type temperature fuse according to claim 2 of the present invention is a temperature fuse in which a low melting point soluble alloy is a fuse element, and the alloy composition of the low melting point soluble alloy is Bi25 to 35% by weight, The composition is characterized in that it has a composition in which 0.5 to 3.5 parts by weight of Ag is added to 100 parts by weight of Sn 2.5 to 10% by weight and the balance In, and the specific resistance is reduced by the addition of Ag. In addition, the variation of the operating temperature can be further suppressed by narrowing the width of the solid-liquid coexistence region without changing the operating temperature.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
In the alloy type temperature fuse according to the present invention, a circular wire having an outer diameter of 200 μmφ to 500 μmφ, preferably 250 μmφ to 350 μmφ, or a flat wire having the same cross-sectional area as that of the circular line can be used as the fuse element.
[0012]
This fuse element alloy is Bi25-35 wt%, Sn2.5-10 wt%, the balance In, preferably Bi29-333 wt%, Sn3-6 wt%, the balance In, and the reference composition is Bi32 0.7 wt%, Sn 3.8 wt%, and In 63.5 wt%, the liquidus temperature is 71 ° C., and the solid-liquid coexistence zone width is 3 ° C.
[0013]
The blending amount of In and Bi temporarily sets the melting point to around 70 ° C. and gives sufficient ductility necessary for thin line drawing. The range of solidus temperature and liquidus temperature is 65 ° C. due to the blending of Sn. The specific resistance is set low while being finally set to ˜75 ° C.
If the lower limit of the amount of Sn is less than the amount of claim 1, not only the amount of Sn is insufficient and it is difficult to achieve the above results, but the above-mentioned solid phase transformation cannot be effectively prevented, and the upper limit of the amount of Sn is not limited. Exceeds the blending amount of claim 1, an In-Bi-Sn eutectic composition (In 42 wt%, Bi 29 wt%, Sn 13 wt%) having a melting point of 62 ° C. appears, and the solidus temperature and liquidus temperature are Not only can the range be kept between 65 ° C. and 75 ° C., but also noticeable variations in the operating temperature due to the bipolarization of the molten peak are inevitable.
With this composition, the total specific resistance can be lowered sufficiently because the total amount of In and Sn with low specific resistance is large compared to Bi with high specific resistance, and the fuse element has a low resistance even under an ultrafine wire of 300 μmφ. Resistance can be easily achieved, and as is apparent from FIG. 1 (DSC measurement result of In-32.7Bi-3.8Sn), solid phase transformation does not occur on the low temperature side of the operating temperature of 65 ° C. to 75 ° C. Since the resistance value change due to the solid phase transformation of the fuse element at the temperature during normal operation of the device with respect to the operating temperature of 65 ° C. to 75 ° C. can be eliminated, the operating temperature of the temperature fuse is set to 70 ° C. As a reference, it can be set within a range of ± 5 ° C.
The fuse element has a resistivity of 25 to 35 μΩ · cm.
[0014]
By adding 0.5 to 3.5 parts by weight of Ag to 100 parts by weight of the alloy composition, the resistivity can be made lower than the above, for example, by adding 3.5 parts by weight, about 10%. Can be lowered.
[0015]
The fuse element of the temperature fuse according to the present invention is manufactured by drawing an alloy base material, and can be used with a round cross section or further compressed into a flat shape.
[0016]
FIG. 2 shows a tape-type alloy-type temperature fuse according to the present invention, in which a strip-shaped lead conductor 1, 1 having a thickness of 100 to 200 μm is attached to an adhesive or a plastic base film 41 having a thickness of 100 to 300 μm. The fuse element 2 having a wire diameter of 250 .mu.m.phi. To 500 .mu.m.phi. Is connected between the belt-shaped lead conductors by bonding, and a flux 3 is applied to the fuse element 2, and the flux coating fuse element is thickened. It is sealed with an adhesive or fusion bonding of a 100 to 300 μm plastic cover film 41.
[0017]
The alloy type temperature fuse according to the present invention can also be implemented in the form of a cylindrical case type, a case type radial type, a substrate type, or a resin mold radial type.
FIG. 3 shows a cylindrical case type. A low melting point soluble alloy piece 2 is connected between a pair of lead wires 1 and 1, and a flux 3 is applied onto the low melting point soluble alloy piece 2. A heat-resistant and heat-conductive insulating cylinder 4, for example, a ceramic cylinder, is inserted over the flux-coated low-melting-point soluble alloy piece, and room temperature curing is performed between each end of the insulating cylinder 4 and each lead wire 1. Sealed with an adhesive, for example, an epoxy resin.
[0018]
FIG. 4 shows a case type radial type, in which a fuse element 2 is joined between the leading ends of the parallel lead conductors 1 and 1 by welding, and a flux 3 is applied to the fuse element 2. The coating fuse element is surrounded by an insulating case 4 having an opening at one end, for example, a ceramic case, and the opening of the insulating case 4 is sealed with a sealing material 5 such as an epoxy resin.
[0019]
FIG. 5 shows a substrate type. A pair of film electrodes 1 and 1 are formed on an insulating substrate 4, for example, a ceramic substrate, by printing and baking a conductive paste (for example, a silver paste). The conductor 11 is connected by welding or the like, the fuse element 2 is joined by welding between the electrodes 1 and 1, the flux 3 is applied to the fuse element 2, and the flux application fuse element is connected to the sealing material 4. For example, it is sealed with an epoxy resin.
[0020]
FIG. 6 shows a resin mold radial type, in which a fuse element 2 is joined between the end portions of the parallel lead conductors 1 and 1 by welding, and a flux 3 is applied to the fuse element 2. The coating fuse element is resin molded 5 by resin liquid dipping.
[0021]
In addition, a resistor (film resistance) is attached to a fuse with an energizing heating element, for example, an insulating substrate of a substrate type alloy-type temperature fuse, and when a device malfunctions, the resistor is energized to generate heat. It can also be implemented in the form of a substrate-type fuse with resistance that melts the low-melting-point soluble alloy piece with heat.
[0022]
As the above-mentioned flux, one having a melting point lower than that of the fuse element is usually used. For example, 90 to 60 parts by weight of rosin, 10 to 40 parts by weight of stearic acid, and 0 to 3 parts by weight of an activator are used. it can. In this case, natural rosin, modified rosin (eg, hydrogenated rosin, disproportionated rosin, polymerized rosin) or purified rosin can be used as the rosin, and diethylamine hydrochloride or hydrobromic acid can be used as the activator. Salt and the like can be used.
[0023]
【Example】
[Example 1]
A base material having an alloy composition of 63.5 wt% In, 32.7 wt% Bi, and 3.8 wt% Sn was drawn and processed into a wire having a diameter of 300 μmφ. The pulling rate for one die was 6.5%, and the drawing speed was 45 m / min, but there was no disconnection.
The resistivity of this line was measured and found to be 32 μΩ · cm.
This line was cut to a length of 4 mm to form a fuse element, and a tape type temperature fuse was prepared. The flux used was a composition of 80 parts by weight of rosin, 20 parts by weight of stearic acid, and 1 part by weight of diethylamine hydrobromide. Polyethylene terephthalate having a thickness of 200 μm was used for the plastic base film and the plastic cover film. -A film was used.
[0024]
50 pieces of this example product were immersed in an oil bath with a heating rate of 1 ° C./min while applying a current of 0.1 ampere, and the oil temperature at the time of cutting off the current due to fusing was measured. It was within the range of ° C. When the same measurement was performed with the energization current being 1/10, no difference was observed substantially, and it was confirmed that there was no influence of self-heating.
Further, within the range of the alloy composition described above, the operating temperature could be kept within a range of ± 5 ° C. centering on 70 ° C.
[0025]
[Example 2]
A base material having an alloy composition of In 61.3 wt%, Bi 31.6 wt%, Sn 3.7 wt%, and Ag 3.4 wt% was drawn into a wire having a diameter of 300 μmφ. The pulling rate for one die was 6.5%, and the drawing speed was 45 m / min, but there was no disconnection. The resistivity of this line was measured and found to be 29 μΩ · cm.
This line was cut to a length of 4 mm to form a fuse element, and a tape type temperature fuse similar to that in Example 1 was prepared.
[0026]
50 pieces of this example product were immersed in an oil bath with a heating rate of 1 ° C./min while applying a current of 0.1 ampere, and the oil temperature at the time of cutting off the current due to fusing was measured. It was within the range of ° C. When the same measurement was performed with the energization current being 1/10, no difference was observed substantially, and it was confirmed that there was no influence of self-heating.
Further, within the range of the alloy composition described above, the operating temperature could be kept within a range of ± 4 ° C. centering on 70 ° C.
[0027]
[Comparative example]
A base material having an alloy composition of 66.3% by weight of In and 33.7% by weight of Bi was drawn and processed into a wire having a diameter of 300 μmφ. The pulling rate for one die was 6.5%, and the drawing speed was 45 m / min, but there was no disconnection.
The resistivity of this line was measured and found to be 37 μΩ · cm.
This line was cut to a length of 4 mm to form a fuse element. A tape type temperature fuse was prepared in the same manner as in Example 1, and the operating temperature was measured. The thing which operate | moved at 74 degreeC vicinity was seen, and the variation in operating temperature was recognized.
This is due to the solid phase transformation on the low temperature side, and it was confirmed that Sn was blended in the fuse element of the temperature fuse according to the present invention.
[0028]
【The invention's effect】
According to the present invention, an ultrafine wire fuse element of 300 μmφ class is manufactured by efficient drawing of a Bi—In—Sn low melting point soluble alloy base material that does not affect the biological system. Can be used to obtain an alloy-type temperature fuse that has an operating temperature of 65 ° C. to 75 ° C. and can sufficiently prevent an operation error due to self-heating.
[Brief description of the drawings]
FIG. 1 is a drawing showing DSC measurement results of In-32.7Bi-3.8Sn.
FIG. 2 is a drawing showing an example of an alloy type temperature fuse according to the present invention.
FIG. 3 is a drawing showing another example of the alloy type temperature fuse according to the present invention.
FIG. 4 is a drawing showing another example of the alloy type temperature fuse according to the present invention.
FIG. 5 is a drawing showing another example of the alloy type temperature fuse according to the present invention.
FIG. 6 is a drawing showing another example of the alloy type temperature fuse according to the present invention.
FIG. 7 is a drawing showing DSC measurement results of In-33.7Bi.
[Explanation of symbols]
2 fuse elements

Claims

In a temperature fuse in which a low melting point fusible alloy is a fuse element, the alloy composition of the low melting point fusible alloy is Bi25 to 35 wt%, Sn 2.5 to 10 wt%, and the balance In. Alloy type temperature fuse to be used.

In a temperature fuse in which a low melting point soluble alloy is a fuse element, the alloy composition of the low melting point soluble alloy is 25 to 35% by weight of Bi, 2.5 to 10% by weight of Sn, and Ag in 100 parts by weight of the balance In. An alloy type temperature fuse characterized by having a composition with 0.5 to 3.5 parts by weight added.