JP2005029833A - Fusible alloy and thermal fuse - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fusible alloy suitably used for electronic equipment such as lighting equipment and fusing at 160 to 190°C and also to provide a thermal fuse operating at 160 to 190°C by using this fusible alloy. <P>SOLUTION: The fusible alloy has a composition consisting of, by weight, 5 to 33% In, 4.7 to 15.5% Zn and the balance Sn with inevitable impurities. The thermal fuse is constituted by welding a fuse element using the fusible alloy to a couple of lead terminals and carrying out sealing with a case. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００６０】
（表１）には、各サンプルについての液相化温度、固相化温度、液相化温度判定、固相−液相温度差分、差分判定（３５℃未満）、総合判定が表記されている。まず、液相化温度判定では液相化温度が、所望の１６０℃〜１９０℃の範囲にあるか否かで○、×判定がなされる。次に、差分判定では固相−液相温度差分から○、×判定がなされる。このとき、固相−液相温度差分が３５℃未満の時を○、３５℃以上の時を×として判定してある。液相化温度が所望の１６０℃〜１９０℃に存在している場合であっても、溶融温度は固相化温度と液相化温度の間に存在するため、この差分があまりに大きいと、溶融温度にばらつきが生じ、可溶合金ならびにこれを用いたヒューズエレメントの溶断性能の信頼性が著しく低下することになる。このため、液相化温度が所望の１６０℃〜１９０℃に存在しただけでは、十分な溶融性能を持つ可溶合金とはいえない。
【００６１】
ここで、溶融温度は液相化温度と固相化温度の間のいずれかに存在し、所望の溶融温度は１６０℃〜１９０℃であるために、溶融温度はこの差である３０℃の間に存在する。この３０℃を基本として、実際の溶融温度が液相化温度と固相化温度の間であって、且つ液相化温度の近傍に存在することを考慮すれば、液相化温度と固相化温度の差分が３５℃未満である場合が、十分な溶融性能を持つものであると判断し、判定を行った。
【００６２】
（表１）の総合判定では、液相化温度判定と差分判定の両方で○と判定されてサンプルのみが○と判定され、それ以外は×と判定された。この総合判定の結果から明らかな通り、サンプル８〜サンプル１７までが総合判定「○」と判定され、これら以外は総合判定「×」と判定された。
【００６３】
サンプル１についてはＩｎの比率が４９．８ｗｔ％と高いために、Ｉｎのもつ溶融温度低下のファクターが強く働き、液相化温度が１０８．９℃と所望の溶融温度を大きく下回っている。サンプル２、サンプル３、サンプル４、サンプル５もそれぞれＩｎの組成比率が高いために、同様に液相化温度が低くなってしまい、所望の溶融温度が実現できない結果となっている。
【００６４】
一方、サンプル６はＺｎの比率が１７ｗｔ％と大きいために、液相化温度は十分であるものの、固相−液相温度の差分が４５．７℃と非常に大きくなり、液相化温度は１６７．５℃と所望の範囲にあるが、実際の溶融温度が１６０℃〜１９０℃に確実におさまることが不十分なため、総合判定は×となっている。
【００６５】
逆に、サンプル７とサンプル１８はＺｎの比率が低すぎるために、同様に固相−液相温度差分が大きすぎて、総合判定として×と判定される。
【００６６】
またサンプル１９、２０はＩｎの比率が低すぎるために、液相化温度が１９０℃を超える温度となり、所望の１６０℃〜１９０℃での溶融が確実には期待できず、これらも総合判定として「×」とされている。
【００６７】
以上のような実施例により、上記組成比の可溶合金が所望の１６０℃〜１９０℃の溶融温度を有することが確認された。
【００６８】
以上の製作された各サンプルと、これらの実験結果からも、所望の１６０℃〜１９０℃の溶融温度をもつ可溶合金の組成比率は、Ｓｎが５１．５ｗｔ％以上９０．３ｗｔ％以下であり、Ｚｎが４．７ｗｔ％以上１５．５ｗｔ％以下であり、Ｉｎが５ｗｔ％以上３３ｗｔ％以下であることが必要であることが明確である。
【００６９】
（実施の形態２）
図２は本発明の実施の形態２におけるヒューズエレメントの製造工程図である。
【００７０】
ヒューズエレメントは実施の形態１において説明した可溶合金を用いて製造される。図２においては板状体のヒューズエレメントを例として説明するが、線状のヒューズエレメントや楕円形状のヒューズエレメントなどその形状は種々のものであってもよい。
【００７１】
なお、ヒューズエレメントは可溶合金を用いて形成され、後で説明する温度ヒューズにおいて、実際に溶断する部位であり、温度ヒューズの動作温度を決定する部位である。
【００７２】
１は全体工程であり、２は鋳込み工程、３はピレット抽出工程、４は丸線条押し出し加工工程、５は圧延工程の各工程である。鋳込み工程２は溶融している可溶合金を鋳込んで冷却する工程であり、ピレット抽出工程３は鋳込み筒７から筒状のピレットを取り出す工程であり、丸線条押し出し加工工程４は筒状のピレット８から丸線条の可溶合金を抽出する工程であり、圧延工程５は丸線条可溶合金１１を平らで薄い板状に加工する工程である。
【００７３】
６は溶融可溶合金、７は鋳込み筒、８はピレット、９は押し出し器、１０はダイス、１１は丸線状可溶合金、１２はつぶし加工ローラー、１３は板状可溶合金である。溶融可溶合金６は実施の形態１で説明した、組成比率の合金に熱を加えて溶融させたものである。溶融された溶融可溶合金６は鋳込み筒７に注入され、冷却されることで筒状のピレット８が取り出される。取り出されたピレット８は押し出し器９に設置され、高圧の圧力をかけることでダイス１０より丸線状に押し出される。ピレット８が押し出されてダイス１０から吐出されることで、丸線状の形状をした丸線状可溶合金１１が取り出される。取り出された丸線状可溶合金１１はつぶし加工ローラー１２により薄く圧延され、板状の形状を有する板状可溶合金１３に加工される。板状に加工された板状可溶合金１３は所要の幅を持つ大きさに裁断されてヒューズエレメントとして使用される。なお、板状可溶合金１３が裁断されると直方体の形状となるが、必要に応じて角部に面取りを施したり、直方体の四辺の角部を切り取って多角形にしたり、楕円形状にしたりすることも行われる。また、ヒューズエレメントに要求される厚みに応じて、つぶし加工ローラー１２の隙間距離や圧力値を変えることも好適である。
【００７４】
以上の工程により、実施の形態１で説明した組成比率による可溶合金からなる、温度ヒューズに用いられるヒューズエレメントが製造される。
【００７５】
このようにして製造されたヒューズエレメントは、実施の形態１で説明した可溶合金が用いられているため、１６０℃〜１９０℃という所望の温度において溶断する特性をもったものである。
【００７６】
（実施の形態３）
図３は本発明の実施の形態３におけるアキシャルタイプの温度ヒューズの斜視図である。
【００７７】
２０は温度ヒューズであり、２１はケースであり、２２はヒューズエレメントであり、２３はリード端子である。ヒューズエレメント２２は実施の形態１で説明した可溶合金を用いて実施の形態２で説明した工程で作成されたものであり、１６０℃〜１９０℃で溶断する。図４ではヒューズエレメント２２が円弧辺を有する板状体になっているが、直方体や線状であってもよい。
【００７８】
リード端子２３は回路配線の一部に接続されて、通常では電流の導通が確保される。すなわち、ヒューズエレメント２２は可溶合金であり、導電性を有するので、リード端子２３とヒューズエレメント２２が共に導電して、電流の導電が実現される。ケース２１はヒューズエレメント２２とリード端子２３の一部を格納し、図４では内部が透視されているが、実際には樹脂などで形成されたケースであり、全面が覆われている。ケース２１は透明、半透明、非透明のいずれであってもよく、その表面には紫外線インクなどで品番や動作温度などの必要情報が印字されている。ここで、リード端子２３は電気伝導性の有る材料であり、金属が好ましく、具体的には、鉄、ニッケル、銅、アルミニウム、金、銀、スズから選ばれる少なくとも一つの単体材料もしくはそれら金属材料の合金、或いは前述の材料グループから選ばれる少なくとも一つの単体もしくは合金に材料グループ以外の元素を含有させた金属材料等が使用できる。
【００７９】
温度ヒューズ２０は例えば高温となる可能性のある電池表面に装着され、あるいは、照明機器の発熱性の蛍光管や電球の電気回路や電源部分などの配線途中に接続される。このとき、温度ヒューズ２０が装着されている電池や回路などが短絡などにより異常発熱を起こし、１６０℃〜１９０℃の範囲の温度に到達した場合には、この範囲の溶融温度を持つ可溶合金からなるヒューズエレメント２２は溶断する。ヒューズエレメント２２が溶断されると、リード端子２３同士が絶縁されることになり、温度ヒューズ２０を介して接続されている回路の導電が遮断されることになる。導電が遮断されることにより、それ以上の発熱が抑えられ、機器の故障などを未然防止することが可能となる。
【００８０】
このとき、ヒューズエレメント２２は、実施の形態１、２で説明したように１６０℃〜１９０℃で確実に溶断する性能を有しているので、発熱がこの温度範囲に達した場合には、確実に導電が遮断される。以上により、目的とする１６０℃〜１９０℃で動作する温度ヒューズを実現することができる。
【００８１】
なお、リード端子２３の対向距離はヒューズエレメント２２が溶断した後であっても、十分な絶縁性能を維持できるように設定される必要がある。また、ヒューズエレメント２２が溶断した場合に、十分に分断されるようにするために、ロジンなどを主成分とするフラックスをケース２１内部に封入しておくことも望ましい。温度上昇に伴いヒューズエレメント２２より先に溶融したフラックスのもつ表面張力により、溶断したヒューズエレメント２２を分断する力が効果的に加わるからである。
【００８２】
図４は本発明の実施の形態３におけるラジアルタイプの温度ヒューズの斜視図である。
【００８３】
２４は温度ヒューズであり、ラジアルタイプの温度ヒューズであるために、リード端子２３がケース２１の同一の面から出ている。
【００８４】
アキシャルタイプと異なり、二本のリード端子２３の先端部にヒューズエレメント２２を収納したケース２１が存在するので、温度ヒューズ２４を装着したい部位が回路配線と離れた場所にある場合に有用である。すなわち、ヒューズエレメント２２を収納したケース２１を温度上昇する部位に装着し、２本のリード端子２３が一方に向かって伸びているため、温度上昇部位と離れた場所に存在する回路配線と接続することが容易である。以上のように、回路配線と温度上昇部位が離れている場合には、ラジアルタイプの温度ヒューズ２４は有用である。
【００８５】
ここで、温度ヒューズ２４の動作メカニズムはアキシャルタイプの温度ヒューズ２０と同様である。すなわち、電池や照明機器の電源回路などの温度が、何らかの理由で温度上昇した場合に、１６０℃〜１９０℃の温度まで到達すると、可溶合金からなるヒューズエレメント２２が溶断し、リード端子２３同士が絶縁される。これにより回路配線の導電が遮断され、以後の温度上昇が回避され、機器の故障などを未然防止することが可能となる。
【００８６】
なお、アキシャルタイプと同様に、溶断したヒューズエレメント２２が確実に引き離されるようにするために、ケース２１内部にフラックスが封入されることも好適である。
【００８７】
次に、図５は本発明の実施の形態３における薄型温度ヒューズの斜視図である。
【００８８】
薄型温度ヒューズは、図３、図４に示されたアキシャルタイプ、ラジアルタイプと異なり、非常に薄型で構成することが可能なものである。薄型温度ヒューズは、装着に際してより薄型が要求されるような機器、例えば携帯電話などに用いられるパック電池などに有用である。もちろん、これ以外にも薄型が要求される機器への装着に有用である。
【００８９】
２５は薄型温度ヒューズ、２６は基板、２７はカバーフィルムである。薄型温度ヒューズ２５は、まず基板２６に一対のリード端子２３を接着し、次いで一対のリード端子２３にまたがるように実施の形態１で説明した可溶合金からなるヒューズエレメント２２を溶接する。更にヒューズエレメント２２とリード端子２３の一部が覆われるようにカバーフィルム２７により封止される。このとき溶断したヒューズエレメント２２が確実に引き離されるように、ロジンなどを主成分とするフラックスがカバーフィルム２７と基板２６により封止される空間に封入されてもよい。また、カバーを透明、もしくは半透明として内部を可視状態にして、内部にフラックスが封入されていることを容易に確認できるようにしておくことも望ましい。特に、フラックスの主成分であるロジンの成分を調整することで、フラックスを有色として、画像認識を用いた自動判別装置などを用いて良品判定を自動で行うことも好適である。
【００９０】
リード端子２３はアキシャルタイプやラジアルタイプと異なり薄い板状体のものを用いることができ、ケース２１の代わりにＰＥＴやＰＥＮなどにより形成された基板とカバーフィルムを用いて封止されるため、非常に薄型に構成することができる。
【００９１】
薄型温度ヒューズ２５においても、ヒューズエレメント２２は実施の形態１で説明した可溶合金により形成されているため、１６０℃〜１９０℃で確実に溶断する。これにより、１６０℃〜１９０℃程度の温度上昇が発生した場合において以後の導電を遮断したい機器に最適に使用されることができる。
【００９２】
図６は本発明の実施の形態３におけるパック電池の斜視図である。
【００９３】
３０はパック電池、３１は電極端子、３２は溶接部、３３は外部出力端子である。薄型温度ヒューズ２５はパック電池３０の側面に装着されている。パック電池３０は携帯電話などに用いられるため、小型化、薄型化が進んでおり、温度ヒューズはその側面に装着される必要があり、アキシャルタイプやラジアルタイプよりも薄型温度ヒューズが好ましい。
【００９４】
電極端子３１はパック電池の正極、負極のいずれかでありリード端子２３と溶接部３２により電気接続されている。反対側のリード端子２３は溶接部３２により更に外部出力端子３３に接続され、パック電池３０の電源が外部へ供給される。ここで、パック電池３０が異常発熱し、１６０℃〜１９０℃程度の温度まで上昇した場合には、薄型温度ヒューズ２５内部のヒューズエレメント２２が溶断しパック電池からの給電が遮断される。これにより以後の導電が遮断され、発熱による機器の故障などを未然防止することができる。
【００９５】
以上のように、温度ヒューズに実施の形態１で説明した５ｗｔ％以上３３ｗｔ％以下のＩｎと、４．７ｗｔ％以上１５．５ｗｔ％以下のＺｎと、残部のＳｎと不可避不純物とからなる可溶合金により形成されたヒューズエレメントを用いることで、電子機器に装着することにより、１６０℃〜１９０℃を動作温度とする温度ヒューズを実現することができる。
【００９６】
【発明の効果】
本発明では、５ｗｔ％以上３３ｗｔ％以下のＩｎと、４．７ｗｔ％以上１５．５ｗｔ％以下のＺｎと、残部のＳｎと不可避不純物とからなることを特徴とする可溶合金とすることで、１６０℃〜１９０℃で溶融する可溶合金を実現することができる。特に、Ｉｎを９ｗｔ％以上１５ｗｔ％以下とすることで、１６０℃〜１９０℃の溶融温度を有し、溶融温度のばらつきの少ない優れた可溶合金を実現することが可能となる。
【００９７】
更に、ヒューズエレメントに、上記で指定された組成比を有する可溶合金を用いることで、１６０℃〜１９０℃で溶断する温度ヒューズを構成することができる。
【００９８】
更に、この可溶合金からなるヒューズエレメントを用いることで、装着用途に合わせた、アキシャルタイプ、ラジアルタイプ、薄型タイプの温度ヒューズのそれぞれを構成することが可能で、これらを電子機器などに装着することで、異常発熱による電子機器の故障などを未然防止することができる。
【００９９】
また電子機器の故障未然防止により、電子機器の耐久性の向上、寿命延長の向上などが実現される。結果として機器の修理コストも低減できる。
【図面の簡単な説明】
【図１】図１は本発明の実施の形態１における３元組成図
【図２】本発明の実施の形態２におけるヒューズエレメントの製造工程図
【図３】本発明の実施の形態３におけるアキシャルタイプの温度ヒューズの斜視図
【図４】本発明の実施の形態３におけるラジアルタイプの温度ヒューズの斜視図
【図５】本発明の実施の形態３における薄型温度ヒューズの斜視図
【図６】本発明の実施の形態３におけるパック電池の斜視図
【符号の説明】
２０、２４、２５ 温度ヒューズ
２１ ケース
２２ ヒューズエレメント
２３ リード端子
２６ 基板
２７ カバーフィルム
３０ パック電池
３１ 電極端子
３２ 溶接部
３３ 外部出力端子[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fusible alloy for a fuse and a thermal fuse that are suitably used for preventing failure of an electronic device or the like due to abnormal heating or overcurrent.
[0002]
[Prior art]
In order to prevent the occurrence of equipment failure due to abnormal heat generation in batteries used in mobile phones and various electronic equipment, it has become necessary to mount thermal fuses inside batteries and electronic equipment. ing. For example, in a battery, when the positive electrode and the negative electrode are short-circuited for some reason, rapid discharge occurs. The battery suddenly generates heat due to this discharge. This heat generation may cause failure or malfunction of the battery and electronic components present in the vicinity thereof. Also, a device that requires light emission, such as a lighting device, tends to generate heat, and if the heat generation becomes too large, there is a problem such as failure of the lighting device. For this reason, it is required to mount a thermal fuse in lighting equipment and the like.
[0003]
The thermal fuse is provided with terminal portions at both ends of a fuse element made of a fusible alloy that melts when reaching a predetermined temperature, and the terminal portions are connected to a part of the circuit wiring. When an abnormal heat generation occurs in a circuit or the like, the fuse element melts at the temperature due to the abnormal heat generation. By blowing the fuse element, the conduction is cut off, and damage to the battery and other parts is avoided.
[0004]
Here, since the temperature at which the thermal fuse cuts off the conduction is determined by the melting temperature of the fusible alloy constituting the fuse element, the melting temperature of the fusible alloy can be adjusted to determine the operating temperature of the thermal fuse. Necessary. A battery or the like to be mounted on a mobile phone is required to have an operating temperature of around 100 ° C. However, since a lighting device or the like is a device that is expected to generate a certain amount of heat, the operating temperature of the thermal fuse is required to be somewhat high. An operating temperature of from about 0 ° C. to about 190 ° C. is required.
[0005]
In addition, fusible alloys constituting conventional fuse elements often contain environmentally hazardous substances such as Pb. For this reason, conventionally, binary and ternary soluble alloys using elements of In, Sn, and Bi have been used as soluble alloys that do not use Pb, which is an environmentally hazardous substance (for example, patents). Reference 1).
[0006]
[Patent Document 1]
JP 2003-82430 A
[0007]
[Problems to be solved by the invention]
However, binary and ternary soluble alloys using elements of In, Sn, and Bi to avoid Pb have a low melting temperature and operate at 160 ° C. to 190 ° C. required for lighting equipment. There was a problem that a temperature fuse having a temperature could not be constructed.
[0008]
The present invention solves the above-described conventional problems, and does not use Pb, which is an environmentally hazardous substance, and a fusible alloy for a fuse having a melting temperature of 160 ° C to 190 ° C, and an operating temperature of 160 ° C to 190 ° C. An object is to provide a thermal fuse using this fusible alloy.
[0009]
[Means for Solving the Problems]
In the present invention, the fusible alloy contains 5 wt% or more and 33 wt% or less of In and 4.7 wt% or more and 15.5 wt% or less of Zn, with the balance being Sn and inevitable impurities.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
The invention described in claim 1 of the present invention is characterized in that it contains 5 wt% or more and 33 wt% or less of In and 4.7 wt% or more and 15.5 wt% or less of Zn, with the balance being Sn and inevitable impurities. A fusible alloy that melts at 160 ° C. to 190 ° C.
[0011]
The invention according to claim 2 of the present invention is the fusible alloy according to claim 1, wherein In is 9 wt% or more and 15 wt% or less, and melts at 160 ° C. to 190 ° C. It has the effect of reducing variation in melting temperature.
[0012]
The invention according to claim 3 of the present invention is the fusible alloy according to claim 1 or 2, characterized in that the Sn is 51.5 wt% or more and 90.3 wt% or less. Has the effect of melting at 190 ° C.
[0013]
According to a fourth aspect of the present invention, there is provided a fuse element characterized in that the fusible alloy according to any one of the first to third aspects is formed into a plate-like body, a rod state, or a linear body. A fuse element that melts at 160 ° C. to 190 ° C. can be realized.
[0014]
The invention according to claim 5 of the present invention comprises the fuse element according to claim 4, two electrical terminals connected to both ends of the fuse element, and a cover for accommodating at least the fuse element. It is possible to realize a thermal fuse that operates at 160 ° C. to 190 ° C.
[0015]
According to a sixth aspect of the present invention, in the thermal fuse, the two electrical terminals are of a radial type extending in the same direction from the same surface of the cover. A fuse that operates at 160 ° C. to 190 ° C. and can be mounted according to the mounting state can be realized.
[0016]
According to a seventh aspect of the present invention, in the temperature fuse, the temperature type according to the fifth aspect is characterized in that two electrical terminals are extended from the both end faces of the cover one by one. A fuse that operates at 160 ° C. to 190 ° C. and can be mounted according to the mounting state can be realized.
[0017]
According to an eighth aspect of the present invention, there is provided a substrate, a pair of lead terminals provided on the substrate, a fuse element provided so as to straddle the pair of lead terminals, and a cover for accommodating at least the fuse element It is a thermal fuse characterized by the above-mentioned, and a fuse element is a fuse element of Claim 4, Comprising: The thermal fuse which operate | moves in 160 to 190 degreeC is realizable.
[0018]
The invention according to claim 9 of the present invention is characterized in that the cover is transparent or translucent, and a flux having a tint is enclosed inside the cover. It is a fuse and has the effect | action which carries out the division | segmentation of the fuse element fuse | melted reliably.
[0019]
The invention according to claim 10 of the present invention includes a step of weighing 5 wt% or more and 33 wt% or less of In, 4.7 wt% or more and 15.5 wt% or less of Zn and the remaining ratio of Sn, A method for producing a fusible alloy comprising a step of melting a metal in a melting furnace and a step of cooling an alloy produced by melting, wherein the fusible alloy melts at 160 ° C to 190 ° C Can be manufactured.
[0020]
Hereinafter, embodiments will be described with reference to the drawings.
[0021]
(Embodiment 1)
First, the relationship between the melting temperature of the soluble alloy, the liquidus temperature, and the solidus temperature will be described. When a soluble alloy is heated and melted, the phase state generally changes in the order of a solid phase, a solid-liquid coexisting phase, and a liquid phase. Here, the boundary temperature between the solid phase and the solid-liquid coexisting phase is the solid phase temperature. The boundary temperature between the solid-liquid coexisting phase and the liquid phase is the liquidus temperature. The melting temperature of the soluble alloy exists between any of these solidification temperatures and liquidus temperatures. In particular, the actual melting temperature is between the solidus temperature and the liquidus temperature, and is in the vicinity of the liquidus temperature. If the difference between the solid phase temperature and the liquid phase temperature is large, the variation in the melting temperature increases. If the difference is small, the variation decreases, and the reliability and life are increased.
[0022]
FIG. 1 is a ternary composition diagram according to Embodiment 1 of the present invention. FIG. 1 shows a ternary relationship among In, Sn, and Zn, and the numbers on each side of the triangle in the figure indicate wt% of each element. The numbers on the bottom of the triangle when looking toward FIG. 1 are the wt% values of Zn, the numbers on the right side are the wt% values of Sn, and the numbers on the left side are the wt% of In. It is a numerical value. The broken line described inside the triangle is a line connected for each element with respect to these wt% values. A portion surrounded by a solid line and hatched is a portion satisfying the composition ratio of the soluble alloy of the present invention.
[0023]
The soluble alloy of the present invention is a ternary alloy composed of three elements of In (indium), Sn (tin), and Zn (zinc) except for inevitable impurities. First, the reason why these three elements of In, Sn, and Zn are used for the fusible alloy will be described.
[0024]
First, In is used because In is highly effective in reducing the melting point of the soluble alloy. A normal single metal has a very high melting point and is not suitable for the purpose of a thermal fuse in which conduction is cut off by fusing. It is necessary to lower the melting point of the fusible alloy to some extent, and In is a very suitable metal element for forming the fusible alloy because of its great effect of lowering the melting point of the fusible alloy. For this reason, when it is desired to lower the melting temperature, the In composition ratio may be increased. When it is desired to increase the melting temperature, the In ratio may be decreased.
[0025]
Next, Sn is easily mixed with other elements such as Zn and In and is a suitable element for forming a uniform alloy. Further, when Sn is contained, there is an effect that the wettability of the soluble alloy is increased. When the wettability of the fusible alloy is increased, it is suitable for coating and the like, and also suitable for stretching by rolling. This is a very suitable metal element. Sn is a very inexpensive metal and is a suitable metal as a main component of the soluble alloy in order to reduce the cost of the soluble alloy.
[0026]
Zn is less effective in lowering the melting point of the fusible alloy than Bi used in the conventional fusible alloy, and the melting temperature of the fusible alloy is set to a temperature as high as 160 ° C. to 190 ° C. This is because it can be adjusted. When Bi is used, the effect of lowering the melting temperature of the fusible alloy is so great that the melting temperature of the fusible alloy is lowered to about 100 ° C, and the target melting temperature is realized. Difficult to do. On the other hand, since the effect of lowering the melting temperature is limited in Zn, there is no such problem and it is an appropriate metal element.
[0027]
Next, the reason why the composition ratio of the fusible alloy of the present invention is assumed that In is 5 wt% or more and 33 wt% or less, Zn is 4.7 wt% or more and 15.5 wt% or less, and the balance is Sn and inevitable impurities. .
[0028]
First, the reason why In is set to 5 wt% or more and 33 wt% or less will be described. When In is less than 5 wt%, the effect of In that the melting point of the soluble alloy is lowered does not work sufficiently, and the liquidus temperature of the soluble alloy is 190 ° C. regardless of the composition ratio of other metal elements. That's it. For this reason, in order to achieve the target melting temperature of 160 ° C. to 190 ° C., it is necessary to contain 5 wt% or more of In. On the other hand, if it is higher than 33 wt%, the liquidus temperature will be too low and will be below 160 ° C. For this reason, the melting temperature existing between the solid phase temperature and the liquid phase temperature is also less than 160 ° C., and a melting temperature of 160 ° C. to 190 ° C. cannot be realized. For this reason, the ratio of In needs to be 5 wt% or more and 33 wt% or less. Moreover, when the ratio of In becomes very large, it is necessary to make it 33 wt% or less because the linear soluble alloys are likely to stick to each other when the linear soluble alloys are used. . In addition, In is expensive compared to other metal elements, and there is a problem that the cost increases if the In composition ratio is too high. For this reason, it is desirable to keep the In ratio low from the viewpoint of cost.
[0029]
Note that In is preferably 9 wt% or more and 15 wt% or less. As will be described in the experimental results in the following examples, by making In the composition ratio, the difference between the liquidus temperature and the solidus temperature is reduced, and the melting temperature variation is reduced. This is because it is possible to improve the fusing performance of the fuse element using. Of course, by making In 5 wt% or more and 33 wt% or less, it is possible to realize a soluble alloy having a desired melting temperature of 160 ° C. to 190 ° C.
[0030]
Next, the reason why Zn is made 4.7 wt% or more and 15.5 wt% or less will be described. By containing Zn, a melting temperature of 160 ° C. to 190 ° C. can be realized from a ratio relationship with In that lowers the melting temperature. At this time, when Zn is less than 4.7 wt%, two peaks are generated in the temperature curve of the melting temperature of the soluble alloy, and there is a problem that the melting temperature is not stable. If there are two peaks on the temperature curve that is the melting temperature, a thermal fuse that operates at a temperature other than the operating temperature is formed, which is disadvantageous because sufficient reliability cannot be ensured. Further, when the Zn ratio is less than 4.7 wt%, the difference between the solid phase and the liquid phase becomes large, fusing tends to vary, and there is a problem that reliability is lowered. For this reason, it is necessary to contain 4.7 wt% or more of Zn.
[0031]
On the other hand, when Zn is contained in an amount of 15.5 wt% or more, the melting temperature is lowered, so that it is difficult to blow at a desired melting temperature of 160 ° C. to 190 ° C. In this case, as a matter of course, the desired operating temperature of the thermal fuse using this becomes difficult and unusable. From the above, the optimum content ratio of Zn is 4.7 wt% or more and 15.5 wt% or less.
[0032]
Next, with regard to Sn, since the inclusion effect is that the mixing with other metal elements is promoted in addition to the melting temperature and the wettability of the soluble alloy is improved, the remaining content ratio of In and Zn remains. It is sufficient to contain with the ratio of. That is, since In is 5 wt% or more and 33 wt% or less and Zn is 4.7 wt% or more and 15.5 wt% or less, the content ratio of Sn may be 51.5 wt% or more and 90.3 wt% or less. . In particular, since Sn is less expensive than In, it is preferable to increase the content ratio of Sn compared to In in order to reduce the cost of a fusible alloy, and thus a thermal fuse.
[0033]
With the above composition of 5 wt% or more and 33 wt% or less of In, 4.7 wt% or more and 15.5 wt% or less of Zn, the balance of Sn and the unavoidable impurities, the melting property at the target 160 ° C. to 190 ° C. An alloy can be obtained.
[0034]
Here, inevitable impurities are other elements that cannot be completely prevented from being mixed during production, oxides generated during melting, and the like. Examples of other elements that may be mixed as unavoidable impurities include Al, Ag, Sb, As, Fe, Cu, Pb, and Bi.
[0035]
Next, an example in which a sample of a fusible alloy was actually produced and experimented will be described to clarify the characteristics of the fusible alloy according to the present invention.
[0036]
【Example】
A fusible alloy was prepared according to a predetermined composition ratio, and a thermal fuse using a fuse element made of this fusible body was actually manufactured as a sample.
[0037]
In preparation, first, In having a purity of 99.99% or more, Sn having a purity of 99.99% or more, and Zn having a purity of 99.99% or more were weighed in a weight ratio defined for each sample, and placed in a melting furnace. I put it in. In the melting furnace, a temperature state of 350 ° C. or higher is maintained, and melting is performed for a sufficient time until each metal is completely melted. At the stage of melting, stirring is also performed to produce an alloy having a uniform distribution. After sufficiently stirring and melting, the sample was cooled at room temperature for a sufficient time to obtain a soluble alloy sample. About the obtained soluble alloy, the solidification temperature, liquidus temperature, and the difference were measured, and it was confirmed whether it had desired melting temperature and melting performance. For these confirmation experiments, DSC (differential scanning calorimeter) manufactured by Seiko Instruments Inc. was used.
[0038]
Sample 1 is a fusible alloy produced with a composition ratio of 42 wt% Sn, 8.2 wt% Zn, and 49.8 wt% In.
[0039]
Sample 2 is a fusible alloy produced with a composition ratio of Sn 47.4 wt%, Zn 11.5 wt%, and In 41.1 wt%.
[0040]
Sample 3 is a fusible alloy produced with a composition ratio of 27.9 wt% Sn, 10.0 wt% Zn, and 62.1 wt% In.
[0041]
Sample 4 is a fusible alloy produced with a composition ratio of 56.7 wt% Sn, 5.3 wt% Zn, and 38 wt% In.
[0042]
Sample 5 is a fusible alloy manufactured with a composition ratio of Sn of 60.1 wt%, Zn of 6.1 wt%, and In of 33.8 wt%.
[0043]
Sample 6 is a fusible alloy made with a composition ratio of 65.65 wt% Sn, 17.0 wt% Zn, and 20.35 wt% In.
[0044]
Sample 7 is a fusible alloy produced with a composition ratio of Sn of 74.18 wt%, Zn of 4.6 wt%, and In of 21.22 wt%.
[0045]
Sample 8 is a fusible alloy produced with a composition ratio of 68.39 wt% Sn, 9.57 wt% Zn, and 22.05 wt% In.
[0046]
Sample 9 is a fusible alloy produced with a composition ratio of Sn of 74.3 wt%, Zn of 8.38 wt%, and In of 17.32 wt%.
[0047]
Sample 10 is a fusible alloy having a composition ratio of 77.22 wt% Sn, 5.8 wt% Zn, and 16.98 wt% In.
[0048]
Sample 11 is a fusible alloy produced with a composition ratio of Sn of 69.6 wt%, Zn of 15.3 wt%, and In of 15.1 wt%.
[0049]
Sample 12 is a soluble alloy produced with a composition ratio of 76.12 wt% Sn, 10.16 wt% Zn, and 13.72 wt% In.
[0050]
Sample 13 is a fusible alloy produced with a composition ratio of Sn of 82.09 wt%, Zn of 4.75 wt%, and In of 13.06 wt%.
[0051]
Sample 14 is a soluble alloy produced with a composition ratio of Sn of 79.17 wt%, Zn of 7.4 wt%, and In of 13.43 wt%.
[0052]
Sample 15 is a soluble alloy produced with a composition ratio of Sn of 79.77 wt%, Zn of 10.64 wt%, and In of 9.59 wt%.
[0053]
Sample 16 is a soluble alloy produced with a composition ratio of Sn of 85.86 wt%, Zn of 4.97 wt%, and In of 9.8 wt%.
[0054]
Sample 17 is a soluble alloy produced with a composition ratio of Sn of 82.88 wt%, Zn of 7.74 wt%, and In of 9.38 wt%.
[0055]
Sample 18 is a fusible alloy produced with a composition ratio of Sn: 76.91 wt%, Zn: 2.26 wt%, and In: 20.83 wt%.
[0056]
Sample 19 is a fusible alloy produced with a composition ratio of Sn of 86.96 wt%, Zn of 8.12 wt%, and In of 4.92 wt%.
[0057]
Sample 20 is a fusible alloy produced with a composition ratio of 90.8 wt% Sn, 6.1 wt% Zn, and 3.1 wt% In.
[0058]
The experimental results of each of these samples are shown in (Table 1).
[0059]
[Table 1]

[0060]
(Table 1) describes the liquidus temperature, the solidification temperature, the liquidus temperature determination, the solid-liquid phase temperature difference, the difference determination (less than 35 ° C.), and the overall determination for each sample. . First, in the determination of the liquidus temperature, the determination of “◯” or “X” is made based on whether or not the liquidus temperature is in a desired range of 160 ° C. to 190 ° C. Next, in the difference determination, “◯” and “X” are determined from the solid-liquid phase temperature difference. At this time, it is determined that the solid-liquid phase temperature difference is less than 35 ° C., and the case where it is 35 ° C. or more is determined as x. Even if the liquidus temperature is between 160 ° C and 190 ° C, the melting temperature exists between the solidification temperature and the liquidus temperature, so if this difference is too large, The temperature varies, and the reliability of the fusible performance of the fusible alloy and the fuse element using the fusible alloy is significantly lowered. For this reason, it cannot be said that it is a soluble alloy having sufficient melting performance if the liquidus temperature is present at a desired temperature of 160 ° C. to 190 ° C.
[0061]
Here, the melting temperature exists either between the liquidus temperature and the solidus temperature, and the desired melting temperature is 160 ° C to 190 ° C. Exists. Based on this 30 ° C., considering that the actual melting temperature is between the liquidus temperature and the solidus temperature and is in the vicinity of the liquidus temperature, the liquidus temperature and the solid phase The case where the difference in the conversion temperature was less than 35 ° C. was judged as having sufficient melting performance, and the determination was made.
[0062]
In the comprehensive determination of (Table 1), it was determined as ◯ in both the liquidus temperature determination and the difference determination, and only the sample was determined as ◯, and other than that was determined as x. As is apparent from the result of this comprehensive determination, samples 8 to 17 were determined to be comprehensive determination “◯”, and the others were determined to be comprehensive determination “x”.
[0063]
In sample 1, since the In ratio is as high as 49.8 wt%, the melting temperature lowering factor of In works strongly, and the liquidus temperature is 108.9 ° C., which is much lower than the desired melting temperature. Since Sample 2, Sample 3, Sample 4, and Sample 5 each have a high In composition ratio, the liquidus temperature is similarly lowered, and the desired melting temperature cannot be realized.
[0064]
On the other hand, since the sample 6 has a large Zn ratio of 17 wt%, the liquidus temperature is sufficient, but the difference between the solid phase and the liquid phase temperature is as large as 45.7 ° C., and the liquidus temperature is Although it is in a desired range of 167.5 ° C., since the actual melting temperature does not sufficiently fall within the range of 160 ° C. to 190 ° C., the comprehensive judgment is “x”.
[0065]
On the contrary, since the ratio of Zn in Sample 7 and Sample 18 is too low, the difference between the solid phase and the liquid phase temperature is similarly too large, and the overall determination is determined as x.
[0066]
In addition, since the ratio of In in Samples 19 and 20 is too low, the liquidus temperature exceeds 190 ° C., and melting at a desired 160 ° C. to 190 ° C. cannot be expected with certainty. “×”.
[0067]
From the above examples, it was confirmed that the soluble alloy having the above composition ratio had a desired melting temperature of 160 ° C. to 190 ° C.
[0068]
From each of the above-produced samples and the results of these experiments, the composition ratio of the soluble alloy having a desired melting temperature of 160 ° C. to 190 ° C. is Sn of 51.5 wt% or more and 90.3 wt% or less. It is clear that Zn must be 4.7 wt% or more and 15.5 wt% or less, and In must be 5 wt% or more and 33 wt% or less.
[0069]
(Embodiment 2)
FIG. 2 is a manufacturing process diagram of the fuse element according to the second embodiment of the present invention.
[0070]
The fuse element is manufactured using the fusible alloy described in the first embodiment. In FIG. 2, a plate-like fuse element is described as an example, but the shape may be various, such as a linear fuse element or an elliptical fuse element.
[0071]
Note that the fuse element is formed using a fusible alloy, and is a part that is actually melted in a thermal fuse described later, and is a part that determines the operating temperature of the thermal fuse.
[0072]
1 is an overall process, 2 is a casting process, 3 is a pellet extraction process, 4 is a round wire extrusion process, and 5 is a rolling process. The casting process 2 is a process of casting and cooling a molten alloy that is melted, the pellet extraction process 3 is a process of taking out a cylindrical pellet from the casting cylinder 7, and the round wire extrusion process 4 is a cylinder. The round wire soluble alloy is extracted from the above-described billet 8, and the rolling step 5 is a step of processing the round wire soluble alloy 11 into a flat and thin plate.
[0073]
6 is a melt-soluble alloy, 7 is a casting cylinder, 8 is a pellet, 9 is an extruder, 10 is a die, 11 is a round wire-soluble alloy, 12 is a crushing roller, and 13 is a plate-like soluble alloy. The melt-soluble alloy 6 is obtained by applying heat to the alloy having the composition ratio described in the first embodiment and melting it. The melted and meltable alloy 6 is poured into a casting cylinder 7 and cooled to take out a cylindrical pillet 8. The removed pillet 8 is placed in an extruder 9 and is pushed out from the die 10 in a round line shape by applying a high pressure. A round wire-shaped soluble alloy 11 having a round wire shape is taken out by ejecting the pellet 8 from the die 10. The taken-out round wire-like soluble alloy 11 is thinly rolled by a crushing roller 12 and processed into a plate-like soluble alloy 13 having a plate-like shape. The plate-like soluble alloy 13 processed into a plate shape is cut into a size having a required width and used as a fuse element. In addition, when the plate-like soluble alloy 13 is cut, it becomes a rectangular parallelepiped shape. However, if necessary, the corners are chamfered, the corners of the four sides of the rectangular parallelepiped are cut into polygons, or the shape is elliptical. It is also done. It is also preferable to change the gap distance and pressure value of the crushing roller 12 according to the thickness required for the fuse element.
[0074]
Through the above steps, a fuse element used for a thermal fuse, which is made of a fusible alloy having the composition ratio described in the first embodiment, is manufactured.
[0075]
The fuse element manufactured as described above has the characteristic of fusing at a desired temperature of 160 ° C. to 190 ° C. because the fusible alloy described in the first embodiment is used.
[0076]
(Embodiment 3)
FIG. 3 is a perspective view of an axial type thermal fuse according to Embodiment 3 of the present invention.
[0077]
20 is a thermal fuse, 21 is a case, 22 is a fuse element, and 23 is a lead terminal. The fuse element 22 is formed by the process described in the second embodiment using the fusible alloy described in the first embodiment, and is blown at 160 ° C. to 190 ° C. In FIG. 4, the fuse element 22 is a plate-like body having an arc side, but may be a rectangular parallelepiped or a line.
[0078]
The lead terminal 23 is connected to a part of the circuit wiring, and normally conduction of current is ensured. That is, since the fuse element 22 is a fusible alloy and has conductivity, the lead terminal 23 and the fuse element 22 are both conducted, and current conduction is realized. The case 21 stores a part of the fuse element 22 and the lead terminal 23. Although the inside is seen through in FIG. 4, it is actually a case made of resin or the like, and is entirely covered. The case 21 may be transparent, translucent, or non-transparent, and necessary information such as a product number and an operating temperature is printed on the surface of the case 21 with ultraviolet ink or the like. Here, the lead terminal 23 is a material having electrical conductivity, and is preferably a metal. Specifically, at least one simple material selected from iron, nickel, copper, aluminum, gold, silver, and tin, or a metal material thereof. Or at least one simple substance selected from the above material group or a metal material containing an element other than the material group in the alloy can be used.
[0079]
The thermal fuse 20 is mounted on, for example, a battery surface that may become high temperature, or is connected in the middle of wiring such as an exothermic fluorescent tube of a lighting device, an electric circuit of a light bulb, or a power supply portion. At this time, when a battery or a circuit to which the thermal fuse 20 is mounted causes abnormal heat generation due to a short circuit or the like and reaches a temperature in the range of 160 ° C. to 190 ° C., a fusible alloy having a melting temperature in this range The fuse element 22 made of is melted. When the fuse element 22 is melted, the lead terminals 23 are insulated from each other, and the conduction of the circuit connected via the thermal fuse 20 is cut off. Since the conduction is cut off, further heat generation can be suppressed, and it is possible to prevent a failure of the device.
[0080]
At this time, since the fuse element 22 has a performance of reliably fusing at 160 ° C. to 190 ° C. as described in the first and second embodiments, when the heat generation reaches this temperature range, it is ensured. The conduction is cut off. As described above, a target thermal fuse operating at 160 ° C. to 190 ° C. can be realized.
[0081]
Note that the facing distance of the lead terminal 23 needs to be set so that sufficient insulation performance can be maintained even after the fuse element 22 is melted. It is also desirable to enclose a flux containing rosin or the like as a main component in the case 21 so that the fuse element 22 is sufficiently divided when the fuse element 22 is melted. This is because a force for dividing the blown fuse element 22 is effectively applied by the surface tension of the flux melted prior to the fuse element 22 as the temperature rises.
[0082]
FIG. 4 is a perspective view of a radial type thermal fuse according to Embodiment 3 of the present invention.
[0083]
Reference numeral 24 denotes a thermal fuse, which is a radial type thermal fuse, so that the lead terminal 23 protrudes from the same surface of the case 21.
[0084]
Unlike the axial type, there is a case 21 in which the fuse element 22 is housed at the tip of the two lead terminals 23, which is useful when the part where the thermal fuse 24 is to be attached is located away from the circuit wiring. That is, the case 21 containing the fuse element 22 is attached to a portion where the temperature rises, and the two lead terminals 23 extend toward one side, so that they are connected to circuit wiring existing at a location away from the temperature rise portion. Is easy. As described above, the radial type thermal fuse 24 is useful when the circuit wiring and the temperature rising portion are separated from each other.
[0085]
Here, the operating mechanism of the thermal fuse 24 is the same as that of the axial type thermal fuse 20. That is, when the temperature of the power supply circuit of the battery or lighting device rises for some reason and reaches a temperature of 160 ° C. to 190 ° C., the fuse element 22 made of a fusible alloy is melted and the lead terminals 23 are connected to each other. Is insulated. As a result, the conduction of the circuit wiring is cut off, the subsequent temperature rise is avoided, and it is possible to prevent the breakdown of the device.
[0086]
As in the case of the axial type, it is also preferable to enclose the flux inside the case 21 in order to ensure that the fused fuse element 22 is pulled apart.
[0087]
Next, FIG. 5 is a perspective view of a thin thermal fuse in Embodiment 3 of the present invention.
[0088]
Unlike the axial type and radial type shown in FIGS. 3 and 4, the thin thermal fuse can be configured to be very thin. The thin thermal fuse is useful for a device that is required to be thin when mounted, for example, a battery pack used in a mobile phone. Of course, it is useful for mounting on devices that require thinness.
[0089]
Reference numeral 25 is a thin thermal fuse, 26 is a substrate, and 27 is a cover film. In the thin thermal fuse 25, a pair of lead terminals 23 are first bonded to the substrate 26, and then the fuse element 22 made of the fusible alloy described in the first embodiment is welded so as to straddle the pair of lead terminals 23. Further, the fuse element 22 and the lead terminal 23 are sealed with a cover film 27 so as to be covered. At this time, a flux mainly composed of rosin or the like may be enclosed in a space sealed by the cover film 27 and the substrate 26 so that the fused fuse element 22 is reliably pulled away. It is also desirable to make the cover transparent or translucent so that the inside is visible so that it can be easily confirmed that the flux is enclosed inside. In particular, it is also preferable to automatically perform non-defective product determination using an automatic discrimination device using image recognition, etc., by adjusting the rosin component, which is the main component of the flux, so that the flux is colored.
[0090]
Unlike the axial type and the radial type, the lead terminal 23 can be a thin plate-like body, and is sealed using a substrate and a cover film formed of PET, PEN or the like instead of the case 21. It can be configured to be thin.
[0091]
Also in the thin thermal fuse 25, the fuse element 22 is formed of the fusible alloy described in the first embodiment, and thus is surely blown at 160 ° C. to 190 ° C. Thereby, when a temperature rise of about 160 ° C. to 190 ° C. occurs, it can be optimally used for a device that wants to cut off subsequent conduction.
[0092]
FIG. 6 is a perspective view of a battery pack according to Embodiment 3 of the present invention.
[0093]
30 is a battery pack, 31 is an electrode terminal, 32 is a welded portion, and 33 is an external output terminal. The thin thermal fuse 25 is attached to the side surface of the battery pack 30. Since the battery pack 30 is used in a mobile phone or the like, it is becoming smaller and thinner, and the thermal fuse needs to be mounted on the side surface thereof. A thin thermal fuse is preferable to the axial type or radial type.
[0094]
The electrode terminal 31 is either a positive electrode or a negative electrode of the battery pack, and is electrically connected to the lead terminal 23 and the welded portion 32. The lead terminal 23 on the opposite side is further connected to the external output terminal 33 by the welded portion 32, and the power of the battery pack 30 is supplied to the outside. Here, when the battery pack 30 abnormally generates heat and rises to a temperature of about 160 ° C. to 190 ° C., the fuse element 22 inside the thin thermal fuse 25 is melted and power supply from the battery pack is cut off. As a result, the subsequent conduction is cut off, and it is possible to prevent a failure of the device due to heat generation.
[0095]
As described above, the thermal fuse is composed of 5 wt% or more and 33 wt% or less of In, 4.7 wt% or more and 15.5 wt% or less of Zn, and the remaining Sn and inevitable impurities described in the first embodiment. By using a fuse element formed of an alloy, a thermal fuse having an operating temperature of 160 ° C. to 190 ° C. can be realized by being mounted on an electronic device.
[0096]
【The invention's effect】
In the present invention, by forming a soluble alloy characterized by comprising 5 wt% or more and 33 wt% or less of In, 4.7 wt% or more and 15.5 wt% or less of Zn, and the balance of Sn and inevitable impurities, A fusible alloy that melts at 160 ° C. to 190 ° C. can be realized. In particular, by setting In to 9 wt% or more and 15 wt% or less, it is possible to realize an excellent soluble alloy having a melting temperature of 160 ° C. to 190 ° C. and having a small variation in melting temperature.
[0097]
Furthermore, by using a fusible alloy having the composition ratio specified above for the fuse element, it is possible to configure a thermal fuse that melts at 160 ° C. to 190 ° C.
[0098]
Furthermore, by using this fusible alloy fuse element, it is possible to configure each of axial type, radial type, and thin type thermal fuses according to the mounting application, and these can be mounted on electronic devices. Therefore, it is possible to prevent a malfunction of the electronic device due to abnormal heat generation.
[0099]
Further, by preventing failure of the electronic device, it is possible to improve the durability of the electronic device and improve the life extension. As a result, equipment repair costs can be reduced.
[Brief description of the drawings]
FIG. 1 is a ternary composition diagram according to Embodiment 1 of the present invention.
FIG. 2 is a manufacturing process diagram of a fuse element according to a second embodiment of the present invention.
FIG. 3 is a perspective view of an axial type thermal fuse according to a third embodiment of the present invention.
FIG. 4 is a perspective view of a radial type thermal fuse according to a third embodiment of the present invention.
5 is a perspective view of a thin thermal fuse in Embodiment 3 of the present invention. FIG.
FIG. 6 is a perspective view of a battery pack according to Embodiment 3 of the present invention.
[Explanation of symbols]
20, 24, 25 Thermal fuse
21 cases
22 Fuse element
23 Lead terminal
26 Substrate
27 Cover film
30 pack battery
31 Electrode terminal
32 Welded part
33 External output terminal

Claims (10)

5 wt% or more and 33 wt% or less of In,
Containing 4.7 wt% or more and 15.5 wt% or less of Zn,
A soluble alloy characterized in that the balance consists of Sn and inevitable impurities. The soluble alloy according to claim 1, wherein the In content is 9 wt% or more and 15 wt% or less. The soluble alloy according to claim 1, wherein the Sn is 51.5 wt% or more and 90.3 wt% or less. A fuse element, wherein the fusible alloy according to any one of claims 1 to 3 is formed into a plate-like body, a rod state, or a linear body. A fuse element according to claim 4;
Two electrical terminals connected to both ends of the fuse element;
A thermal fuse comprising a cover for accommodating at least the fuse element. 6. The thermal fuse according to claim 5, wherein the two electrical terminals are of a radial type extending in the same direction from the same surface of the cover. 6. The thermal fuse according to claim 5, wherein the thermal fuse is an axial type in which the two electrical terminals are extended one by one from both end faces of the cover. A substrate,
A pair of lead terminals provided on the substrate;
A fuse element provided to straddle the pair of lead terminals;
A thermal fuse having at least a cover for housing the fuse element;
A thermal fuse, wherein the fuse element is the fuse element according to claim 4. The temperature fuse according to any one of claims 5 to 8, wherein the cover is transparent or translucent, and a flux having a color is sealed inside the cover. A step of weighing 5 wt% or more and 33 wt% or less of In, 4.7 wt% or more and 15.5 wt% or less of Zn and the remaining ratio of Sn;
Melting each of the mixed metals in a melting furnace;
A method for producing a fusible alloy comprising the step of cooling an alloy produced by melting.

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