JP2004247269A

JP2004247269A - Tubular casing type alloyed thermal fuse

Info

Publication number: JP2004247269A
Application number: JP2003056761A
Authority: JP
Inventors: Hideo Shoji; 英夫東海林
Original assignee: Uchihashi Estec Co Ltd
Current assignee: Uchihashi Estec Co Ltd
Priority date: 2002-12-17
Filing date: 2003-03-04
Publication date: 2004-09-02

Abstract

<P>PROBLEM TO BE SOLVED: To set a high holding temperature of a tubular casing type alloyed thermal fuse, and to miniaturize it in an inner diameter ranging from 1.3 ± 0.1 mm to 0.7 ± 0.1 mm while guaranteeing a sufficiently high operating temperature when energizing it. <P>SOLUTION: In this thermal fuse wherein a fusible alloy piece 3 is connected between reed conductors 2, 2, flux 4 is applied to the fusible alloy piece 3 to cover it, an insulating tube 1 is inserted over the reed conductors 2, 2, and a space between each end of the insulating tube 1 and each reed conductor 2 is sealed with an adhesive 5, the outer diameter of the fusible alloy piece 3 is 0.59-0.80 times as large as the inner diameter of the insulating tube 1. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は筒状ケースタイプの合金型温度ヒューズに関するものである。
【０００２】
【従来の技術】
電気機器のサーモプロテクタとして合金型温度ヒューズが汎用されている。
この合金型温度ヒューズは、所定融点の合金をヒューズエレメントとし、このヒューズエレメントにフラックスを塗布し、このフラックス塗布ヒューズエレメントを絶縁体で封止した構成であり、就中、筒状ケースタイプ合金型温度ヒューズでは、図４に示すように、リード導体２’，２’間に可溶合金片３’を接続し、該可溶合金片３’を覆ってフラックス４’を塗布し、リード導体２’，２’にまたがって絶縁筒１’を挿通し、絶縁筒１’の各端部と各リード導体２’の間を接着剤５’で封止してあり、リード導体２’，２’間に可溶合金片３’を接続する際、両者の融点の差異のために溶融軟化された可溶合金片端部に硬いリード導体が押し込まれて可溶合金片端部がコブ状ｅとなっている。
この合金型温度ヒューズの動作機構は次ぎの通りである。
保護しようとする電気機器に合金型温度ヒューズが熱的に接触して配設される。電気機器が何らかの異常により発熱すると、その発生熱により温度ヒューズのヒューズエレメントが溶融され、既溶融フラックスとの共存下、溶融合金がリード導体への濡れにより分断球状化され、その分断球状化の進行により通電が遮断され、この通電遮断による機器の降温で分断溶融合金が凝固されて非復帰のカットオフが終結される。
【０００３】
而して、可溶合金片の温度が融点Ｔｍに達したときの温度ヒユーズの周囲温度、すなわち機器温度（Ｔｘ）で温度ヒユーズが動作される。すなわち、機器温度が温度Ｔｘに達したときに温度ヒユーズが動作される。
より詳しくは、可溶合金片の抵抗をＲ、リード導体の抵抗をＲ’、可溶合金片の通電電流をｉとすれば、可溶合金片のジュール発生熱がｉ^２Ｒ、リード導体のジュール発生熱がｉ^２Ｒ’で与えられ、可溶合金片ジュール発生熱のうちリード導体を経て流出される熱量をαｉ^２Ｒ（α＜１）、リード導体ジュール発生熱のうち可溶合金片に伝達される熱量をβｉ^２Ｒ’（β＜１）、可溶合金片から周囲に流出する熱量に基づき可溶合金片を昇温させるのに関与する係数（熱抵抗）をｈ、可溶合金片温度をＴｙ、周囲温度をＴｘとすれば、
【０００４】
【数１】
Ｔｙ＝〔（１−α）Ｒ＋βＲ’〕ｉ^２・ｈ＋Ｔｘ（１）
が成立する。
温度ヒユーズの動作温度Ｔｘ１は、可溶合金片温度Ｔｙが可溶合金の融点Ｔｍになるときの周囲温度Ｔｘで与えられ、
【０００５】
【数２】
Ｔｘ１＝Ｔｍ−〔（１−α）Ｒ＋βＲ’〕ｉ^２・ｈ（２）
が成立する。
通電電流ｉが実質的に０の場合は、周囲温度Ｔｘがほぼ可溶合金片融点になったときに温度ヒユーズが動作し、この際の周囲温度Ｔｘ０が動作温度（カットオフ温度）と称されている。
【０００６】
上記において、可溶合金片の直径をｄ、リード導体の直径をｄ’とすれと、可溶合金片の抵抗Ｒが１／ｄ^２に比例し、リード導体の抵抗Ｒ’が１／ｄ’^２に比例するから、上記式（２）の通電時動作温度は、
【０００７】
【数３】

で表わすことができる（ただし、ｋ、ｋ’は可溶合金片の比抵抗や長さ、リード導体の比抵抗や長さ等により定まる定数）。
【０００８】
而して、式（３）の第２項を無視できない場合、特に可溶合金片の線径ｄが小さくその抵抗が高かったり通電電流ｉが大きい場合、カットオフ温度Ｔｘ０よりも相当に低い温度Ｔｘ１で温度ヒユーズが動作され、従って、機器が危険状態になる温度よりも低い温度で温度ヒユーズが動作されることになる。
【０００９】
そこで、定格電流を７日間流しつづけても温度ヒューズが動作しない温度ヒューズ外面の最高温度をホールディング温度と定義し、このホールディング温度以下の温度で動作するものを不良品とする規格が定められている（例えば、ＡＮＳＩＵＬ規格等）。
このホールディング温度（ＴＦ）は、定格電流を流した状態での温度ヒューズの周囲温度（Ｔｘ１）と
【数４】
Ｔｘ１＝ＨＴＦ（４）
の関係があり（ただし、Ｈは温度ヒューズ表面と周囲との間の熱抵抗により定まる係数）、一般にＴｘ１を高くできれば、ＴＦも高くなる関係にある。
【００１０】
表１は出願人の製造販売に係る筒状ケースタイプ合金型温度ヒューズの中、図４に示す各部位の寸法が表１に示す通りであるものについて取得した規格を示し、電気定格７Ａ，１２５Ｖに合格し、表１のカットオフ温度及びホールディング温度に合格しており、製品２１３では動作温度１２６±３℃を保証し、定格電流通電のもとでは１０２℃以下での不動作を保証し、製品２１５では動作温度１４５±２℃を保証し、定格電流通電のもとでは１２３℃以下での不動作を保証している。
【表１】

【００１１】
上記に例示した筒状ケースタイプ合金型温度ヒューズは勿論のこと、従来の筒状ケースタイプ合金型温度ヒューズでは、可溶合金片外径を筒状ケース内径の０．５８以下にし、リード導体外径を筒状ケース内径の０．５９以下にしてケース内空間の残存スペース（フラックスもこの残存スペースに含ませてある）を相当に広くしている。
その理由は、実績・経験に依存するところが大きいが、ケース内残存空間を広くして溶融合金の分断球状化の円滑化を図る（例えば、特許文献１参照）とか、ケース内残存空間を広くして溶融合金分断時発生する金属蒸気の密度を小にしてアークを迅速に消滅させる（例えば、特許文献２参照）という技術思想も開示されている。
【００１２】
【特許文献１】
実開昭５８−１２０５４１号公報
【特許文献２】
特開平１０−１２１１１号公報
【００１３】
【発明が解決しようとする課題】
近来、機器の小型化に伴い温度ヒユーズにおいても小型化が進められ、筒状ケースの内径が１．３±０．１ｍｍ〜０．７±０．１ｍｍといった小サイズ筒状ケースタイプ温度ヒユーズが開発されつつある。
しかしながら、かかる小サイズ筒状ケースタイプ温度ヒユーズでは、（可溶合金片の外径）／（ケース内径）の比または（リード導体の外径）／（ケース内径）の比を、従来の０．５８以下または０．５９以下にすると、前記ホールディング温度をカットオフ温度に較べて極めて低く設定しなければならず、機器がまだ充分に安全な温度状態にあるのに、温度ヒユーズが動作してしまい、機器を満足に熱的に保護し得ない事態が発生する。この事態は、筒状ケースタイプ合金型温度ヒューズの小型化に当たって解決しなければならない課題である。
【００１４】
近来、環境保全を重視する動きが加速され、温度ヒューズにおいてもＰｂやＣｄ等の生体系に有害な元素を含まないヒューズエレメントの使用を排除することが企図され、例えばＩｎ−Ｓｎ−Ｂｉ系合金のヒューズエレメントの使用が検討されている。
しかしながら、このＩｎ−Ｓｎ−Ｂｉ系合金等は比抵抗値が高く、前記ホールディング温度をカットオフ温度に較べて極めて低く設定しなければならず、機器がまだ充分に安全な温度状態にあるのに、温度ヒユーズが動作してしまい、機器を満足に熱的に保護し得ない事態が懸念される。
【００１５】
前記通電時動作温度（Ｔｘ１）を高くするためには、可溶合金片の径を太くして可溶合金片の抵抗値Ｒを低くすることが有効である。しかしながら、可溶合金片外径を筒状ケース内径の０．５８以下にしている従来技術では、ケース外径が大となって温度ヒューズの小型化を保証できない。
これに対し、筒状ケース内径をそのままにし可溶合金片の外径を大きくして可溶合金片の抵抗値Ｒを低くすることも考えられるが、可溶合金の球状化分断のためのスペース確保上、可溶合金片の径大化が制約され、この手段のみでは、前記の課題解決に限界がある。
【００１６】
ところで、筒状ケースタイプ合金型温度ヒューズのリード導体径を大きくすれば、可溶合金片ジュール発生熱のリード導体を経ての流出率αを大にでき、またリード導体ジュール発生熱も低減でき、式（３）の温度ヒユーズの通電時動作温度ＴＸ１をカットオフ温度に近付けるのに有効であるばかりか、本発明者の鋭意検討結果によれば、筒状ケースタイプ合金型温度ヒューズのリード導体引っ張り強度を飛躍的に向上できる。
【００１７】
本発明の目的は、筒状ケースタイプ合金型温度ヒューズのホールディング温度を高く設定することを可能にし、更に筒状ケースタイプ合金型温度ヒューズのリード導体の引っ張り強度の向上を図り、更にケース内径１．３±０．１ｍｍ〜０．７±０．１ｍｍといった小型化を充分に高い通電時動作温度を保証しつつ可能にすることにある。
本発明の更なる目的は、ヒューズエレメントとして比抵抗値の高い鉛フリー合金を使用しても、筒状ケースタイプ合金型温度ヒューズのホールディング温度を高く設定することを可能にし、更に筒状ケースタイプ合金型温度ヒューズのリード導体の引っ張り強度の向上を図り、更にケース内径１．３±０．１ｍｍ〜０．７±０．１ｍｍといった小型化を充分に高い通電時動作温度を保証しつつ可能にすることにある。
【００１８】
【課題を解決するための手段】
請求項１に係る筒状ケースタイプ合金型温度ヒューズは、リード導体間に可溶合金片が接続され、該可溶合金片を覆ってフラックスが塗布され、リード導体にまたがって絶縁筒が挿通され、絶縁筒の各端部と各リード導体の間が接着剤で封止されてなる温度ヒユーズにおいて、リード導体の外径が絶縁筒内径の０．６０〜０．９０倍好ましくは０．６６〜０．９０倍とされていることを特徴とする。
【００１９】
請求項２に係る筒状ケースタイプ合金型温度ヒューズは、リード導体間に可溶合金片が接続され、該可溶合金片を覆ってフラックスが塗布され、リード導体にまたがって絶縁筒が挿通され、絶縁筒の各端部と各リード導体の間が接着剤で封止されてなる温度ヒユーズにおいて、可溶合金片の外径が絶縁筒内径の０．５９〜０．８０倍好ましくは０．６０〜０．８０倍とされていることを特徴とする。
【００２０】
請求項３に係る筒状ケースタイプ合金型温度ヒューズは、リード導体間に可溶合金片が接続され、該可溶合金片を覆ってフラックスが塗布され、リード導体にまたがって絶縁筒が挿通され、絶縁筒の各端部と各リード導体の間が接着剤で封止されてなる温度ヒユーズにおいて、可溶合金片の外径が絶縁筒内径の０．５９〜０．８０倍好ましくは０．６０〜０．８０倍とされ、かつリード導体の外径が絶縁筒内径の０．６０〜０．９０倍好ましくは０．６６〜０．９０倍とされていることを特徴とする。
【００２１】
請求項４に係る筒状ケースタイプ合金型温度ヒューズは、各リード導体に鍔が設けられ、該鍔に可溶合金片の各端が接続されていることを特徴とする１〜３何れか記載の筒状ケースタイプ合金型温度ヒューズである。
【００２２】
請求項５に係る筒状ケースタイプ合金型温度ヒューズは、絶縁筒の内径が１．４ｍｍ〜０．６ｍｍとされている請求項１〜４何れか記載の筒状ケースタイプ合金型温度ヒューズである。
【００２３】
請求項６に係る筒状ケースタイプ合金型温度ヒューズは、可溶合金片接続部分のリード導体外径が可溶合金片外径の１．０５倍以上とされていることを特徴とする１〜５何れか記載の筒状ケースタイプ合金型温度ヒューズである。
【００２４】
請求項７に係る筒状ケースタイプ合金型温度ヒューズは、可溶合金片がＩｎ−Ｓｎ−Ｂｉ系合金、Ｂｉ−Ｓｎ−Ｓｂ系合金、Ｉｎ−Ｓｎ系合金、Ｉｎ−Ｂｉ系合金、Ｂｉ−Ｓｎ系合金、Ｉｎ系合金の何れかであることを特徴とする請求項１〜６何れか記載の筒状ケースタイプ合金型温度ヒューズである。
【００２５】
請求項８に係る筒状ケースタイプ合金型温度ヒューズは、Ｉｎ−Ｓｎ−Ｂｉ系合金の組成が（１）４３％＜Ｓｎ≦７０％，０．５％≦Ｉｎ≦１０％，残Ｂｉ、（２）２５％≦Ｓｎ≦４０％，５０％≦Ｉｎ≦５５％，残Ｂｉ、（３）２５％＜Ｓｎ≦４４％，５５％＜Ｉｎ≦７４％，１％≦Ｂｉ＜２０％、（４）４６％＜Ｓｎ≦７０％，１８％≦Ｉｎ＜４８％，１％≦Ｂｉ≦１２％、（５）５％≦Ｓｎ≦２８％，１５％≦Ｉｎ＜３７％，残Ｂｉ（但し、Ｂｉ５７．５％，Ｉｎ２５．２％，Ｓｎ１７．３％とＢｉ５４％，Ｉｎ２９．７％，Ｓｎ１６．３％のそれぞれを基準にＢｉ±２％，Ｉｎ及びＳｎ±１％の範囲を除く）、（６）１０％≦Ｓｎ≦１８％，３７％≦Ｉｎ≦４３％，残Ｂｉ、（７）２５％＜Ｓｎ≦６０％，２０％≦Ｉｎ＜５０％，１２％＜Ｂｉ≦３３％、（８）（１）〜（７）の何れか１００重量部にＡｇ、Ａｕ、Ｃｕ、Ｎｉ、Ｐｄ、Ｐｔ、Ｓｂ、Ｇａ、Ｇｅ、Ｐの１種または２種以上を合計０．０１〜７重量部添加、（９）３３％≦Ｓｎ≦４３％，０．５％≦Ｉｎ≦１０％，残Ｂｉ、（１０）４７％≦Ｓｎ≦４９％，５１％≦Ｉｎ≦５３％の１００重量部にＢｉを３〜５重量部を添加、（１１）４０％≦Ｓｎ≦４６％，７％≦Ｂｉ≦１２％，残Ｉｎ、（１２）０．３％≦Ｓｎ≦１．５％，５１％≦Ｉｎ≦５４％，残Ｂｉ、（１３）２．５％≦Ｓｎ≦１０％，２５％≦Ｂｉ≦３５％，残Ｉｎ、（１４）（９）〜（１３）の何れか１００重量部にＡｇ、Ａｕ、Ｃｕ、Ｎｉ、Ｐｄ、Ｐｔ、Ｓｂ、Ｇａ、Ｇｅ、Ｐの１種または２種以上を合計０．０１〜７重量部添加、（１５）１０％≦Ｓｎ≦２５％，４８％≦Ｉｎ≦６０％，残Ｂｉを１００重量部にＡｇ、Ａｕ、Ｃｕ、Ｎｉ、Ｐｄ、Ｐｔ、Ｓｂ、Ｇａ、Ｇｅ、Ｐの１種または２種以上を合計０．０１〜７重量部添加、Ｂｉ−Ｓｎ−Ｓｂ系合金の組成が（１６）３０％≦Ｓｎ≦７０％，０．３％≦Ｓｂ≦２０％，残Ｂｉ、（１７）（１６）の１００重量部にＡｇ、Ａｕ、Ｃｕ、Ｎｉ、Ｐｄ、Ｐｔ、Ｇａ、Ｇｅ、Ｐの１種または２種以上を合計０．０１〜７重量部添加、Ｉｎ−Ｓｎ系合金の組成が（１８）５２％≦Ｉｎ≦８５％，残Ｓｎ、（１９）（１８）の１００重量部にＡｇ、Ａｕ、Ｃｕ、Ｎｉ、Ｐｄ、Ｐｔ、Ｓｂ、Ｇａ、Ｇｅ、Ｐの１種または２種以上を合計０．０１〜７重量部添加、Ｉｎ−Ｂｉ系合金の組成が（２０）４５％≦Ｂｉ≦５５％，残Ｉｎ、（２１）（２０）の組成の１００重量部にＡｇ、Ａｕ、Ｃｕ、Ｎｉ、Ｐｄ、Ｐｔ、Ｓｂ、Ｇａ、Ｇｅ、Ｐの１種または２種以上を合計０．０１〜７重量部添加、Ｂｉ−Ｓｎ系合金の組成が（２２）５０％＜Ｂｉ≦５６％，残Ｓｎ、（２３）（２２）の１００重量部にＡｇ、Ａｕ、Ｃｕ、Ｎｉ、Ｐｄ、Ｐｔ、Ｇａ、Ｇｅの１種または２種以上を合計０．０１〜７重量部添加、Ｉｎ系合金の組成が（２４）Ｉｎの１００重量部にＡｕ、Ｂｉ、Ｃｕ、Ｎｉ、Ｐｄ、Ｐｔ、Ｇａ、Ｇｅ、Ｐの１種または２種以上を合計０．０１〜７重量部添加、（２５）９０％≦Ｉｎ≦９９．９％，０．１％≦Ａｇ≦１０％の１００重量部にＡｕ、Ｂｉ、Ｃｕ、Ｎｉ、Ｐｄ、Ｐｔ、、Ｇａ、Ｇｅ、Ｐの１種または２種以上を合計０．０１〜７重量部添加、（２６）９５％≦Ｉｎ≦９９．９％，０．１％≦Ｓｂ≦５％の１００重量部にＡｕ、Ｂｉ、Ｃｕ、Ｎｉ、Ｐｄ、Ｐｔ、Ｇａ、Ｇｅ、Ｐの１種または２種以上を合計０．０１〜７重量部添加の何れかであることを特徴とする請求項７記載
の筒状ケースタイプ合金型温度ヒューズである。
【００２６】
【発明の実施の形態】
以下、図面を参照しつつ本発明の実施の形態について説明する。
図１は請求項１に係る筒状ケースタイプ合金型温度ヒューズの一実施例を示す縦断面図である。
図１において、１は耐熱性、熱伝導性、絶縁性に優れた材質、例えばセラミック製の筒状ケースである。２，２は断面円形のリード導体、２１はリード導体先端に設けた鍔である。この鍔は省略することもできる。３はリード導体２，２間に溶接等により接続した断面円形の可溶合金片、４は可溶合金片３を覆いリード導体２，２にわたって塗布したフラックスである。５は筒状ケース１の各端部とリード導体２との間を封止した接着剤であり、例えばフィラー配合のエポキシ樹脂を使用できる。
図１において（リード導体の外径）／（ケース内径）の比を０．６０〜０．９０好ましくは０．６６〜０．９０とし、（可溶合金片の外径）／（ケース内径）の比を従来通り０．５８以下としてある。
【００２７】
図２は請求項２に係る筒状ケースタイプ合金型温度ヒューズの実施例を示す縦断面図である。
図２において、１は前記と同様にセラミックのような耐熱性、熱伝導性、絶縁性に優れた材質の筒状ケース、２，２は断面円形のリード導体、２１はリード導体先端に設けた鍔、３はリード導体２，２間に溶接等により接続した断面円形の可溶合金片、４は可溶合金片３を覆いリード導体２，２にわたって塗布したフラックス、５は筒状ケース１の各端部とリード導体２との間を封止したフィラー配合のエポキシ樹脂等の接着剤である。
図２において、（可溶合金片の外径）／（ケース内径）の比を０．５９〜０．８０好ましくは０．６０〜０．８０とし、（リード導体の外径）／（ケース内径）の比を従来通り０．５９以下としてある。
【００２８】
図３は請求項３に係る筒状ケースタイプ合金型温度ヒューズの実施例を示す縦断面図である。
図３において、１は耐熱性、熱伝導性、絶縁性に優れた材質、例えばセラミック製の筒状ケースである。２，２は断面円形のリード導体であり、前記と同様先端に鍔２１を設けてある。３はリード導体２，２間に溶接等により接続した断面円形の可溶合金片であり、フラックス４を可溶合金片３を覆いリード導体２，２にわたって塗布してある。５は筒状ケース１の各端部とリード導体２との間を封止した接着剤、例えばフィラー配合のエポキシ樹脂である。
図３において、（リード導体の外径）／（ケース内径）の比を０．６０〜０．９０好ましくは０．６６〜０．９０とし、（可溶合金片の外径）／（ケース内径）の比を０．５９〜０．８０好ましくは０．６０〜０．８０としてある。
上記において、可溶合金片３の外径とリード導体２の外径とを異ならせてあるが、等しくすることもできる。
【００２９】
可溶合金片３には、要求されるカットオフ温度に対応できる所定融点の合金が使用される。
環境保全のために生体系に有害な元素を含有しない可溶合金片、例えばＩｎ−Ｓｎ−Ｂｉ系合金、Ｂｉ−Ｓｎ−Ｓｂ系合金、Ｉｎ−Ｓｎ系合金、Ｉｎ−Ｂｉ系合金、Ｂｉ−Ｓｎ系合金、Ｉｎ系合金の合金片を使用することが好ましい。
【００３０】
前記Ｉｎ−Ｓｎ−Ｂｉ系合金の組成としては（１）４３％＜Ｓｎ≦７０％，０．５％≦Ｉｎ≦１０％，残Ｂｉ、（２）２５％≦Ｓｎ≦４０％，５０％≦Ｉｎ≦５５％，残Ｂｉ、（３）２５％＜Ｓｎ≦４４％，５５％＜Ｉｎ≦７４％，１％≦Ｂｉ＜２０％、（４）４６％＜Ｓｎ≦７０％，１８％≦Ｉｎ＜４８％，１％≦Ｂｉ≦１２％、（５）５％≦Ｓｎ≦２８％，１５％≦Ｉｎ＜３７％，残Ｂｉ（但し、Ｂｉ５７．５％，Ｉｎ２５．２％，Ｓｎ１７．３％とＢｉ５４％，Ｉｎ２９．７％，Ｓｎ１６．３％のそれぞれを基準にＢｉ±２％，Ｉｎ及びＳｎ±１％の範囲を除く）、（６）１０％≦Ｓｎ≦１８％，３７％≦Ｉｎ≦４３％，残Ｂｉ、（７）２５％＜Ｓｎ≦６０％，２０％≦Ｉｎ＜５０％，１２％＜Ｂｉ≦３３％、（８）（１）〜（７）の何れか１００重量部にＡｇ、Ａｕ、Ｃｕ、Ｎｉ、Ｐｄ、Ｐｔ、Ｓｂ、Ｇａ、Ｇｅ、Ｐの１種または２種以上を合計０．０１〜７重量部添加、（９）３３％≦Ｓｎ≦４３％，０．５％≦Ｉｎ≦１０％，残Ｂｉ、（１０）４７％≦Ｓｎ≦４９％，５１％≦Ｉｎ≦５３％の１００重量部にＢｉを３〜５重量部を添加、（１１）４０％≦Ｓｎ≦４６％，７％≦Ｂｉ≦１２％，残Ｉｎ、（１２）０．３％≦Ｓｎ≦１．５％，５１％≦Ｉｎ≦５４％，残Ｂｉ、（１３）２．５％≦Ｓｎ≦１０％，２５％≦Ｂｉ≦３５％，残Ｉｎ、（１４）（９）〜（１３）の何れか１００重量部にＡｇ、Ａｕ、Ｃｕ、Ｎｉ、Ｐｄ、Ｐｔ、Ｓｂ、Ｇａ、Ｇｅ、Ｐの１種または２種以上を合計０．０１〜７重量部添加、（１５）１０％≦Ｓｎ≦２５％，４８％≦Ｉｎ≦６０％，残Ｂｉを１００重量部にＡｇ、Ａｕ、Ｃｕ、Ｎｉ、Ｐｄ、Ｐｔ、Ｓｂ、Ｇａ、Ｇｅ、Ｐの１種または２種以上を合計０．０１〜７重量部添加したもの等を使用できる。
前記Ｂｉ−Ｓｎ−Ｓｂ系合金の組成としては（１６）３０％≦Ｓｎ≦７０％，０．３％≦Ｓｂ≦２０％，残Ｂｉ、（１７）（１６）の１００重量部にＡｇ、Ａｕ、Ｃｕ、Ｎｉ、Ｐｄ、Ｐｔ、Ｇａ、Ｇｅ、Ｐの１種または２種以上を合計０．０１〜７重量部添加したもの等を使用できる。
前記Ｉｎ−Ｓｎ系合金の組成としては（１８）５２％≦Ｉｎ≦８５％，残Ｓｎ、（１９）（１８）の１００重量部にＡｇ、Ａｕ、Ｃｕ、Ｎｉ、Ｐｄ、Ｐｔ、Ｓｂ、Ｇａ、Ｇｅ、Ｐの１種または２種以上を合計０．０１〜７重量部添加、Ｉｎ−Ｂｉ系合金の組成が（２０）４５％≦Ｂｉ≦５５％，残Ｉｎ、（２１）（２０）の組成の１００重量部にＡｇ、Ａｕ、Ｃｕ、Ｎｉ、Ｐｄ、Ｐｔ、Ｓｂ、Ｇａ、Ｇｅ、Ｐの１種または２種以上を合計０．０１〜７重量部添加したもの等を使用できる。
前記Ｂｉ−Ｓｎ系合金の組成としては（２２）５０％＜Ｂｉ≦５６％，残Ｓｎ、（２３）（２２）の１００重量部にＡｇ、Ａｕ、Ｃｕ、Ｎｉ、Ｐｄ、Ｐｔ、Ｇａ、Ｇｅの１種または２種以上を合計０．０１〜７重量部添加したもの等を使用できる。
前記Ｉｎ系合金の組成としては（２４）Ｉｎの１００重量部にＡｕ、Ｂｉ、Ｃｕ、Ｎｉ、Ｐｄ、Ｐｔ、Ｇａ、Ｇｅ、Ｐの１種または２種以上を合計０．０１〜７重量部添加、（２５）９０％≦Ｉｎ≦９９．９％，０．１％≦Ａｇ≦１０％の１００重量部にＡｕ、Ｂｉ、Ｃｕ、Ｎｉ、Ｐｄ、Ｐｔ、、Ｇａ、Ｇｅ、Ｐの１種または２種以上を合計０．０１〜７重量部添加、（２６）９５％≦Ｉｎ≦９９．９％，０．１％≦Ｓｂ≦５％の１００重量部にＡｕ、Ｂｉ、Ｃｕ、Ｎｉ、Ｐｄ、Ｐｔ、Ｇａ、Ｇｅ、Ｐの１種または２種以上を合計０．０１〜７重量部添加したもの等を使用できる。
前記リード導体３には、銅導体、錫めっき銅導体等を使用できる。
前記フラックス４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が使用される。活性剤には、ジエチルアミンの塩酸塩や臭化水素酸塩、アジピン酸等の有機酸を使用できる。
前記接着剤５には、フィラー入り硬化性樹脂、好ましくは常温硬化型樹脂を使用され、例えば、アルミナ、シリカ、炭酸カルシゥム等のフィラーを添加したエポキシ樹脂を使用できる。
【００３１】
本発明は可溶合金片の細線化のために可溶合金片の抵抗値が高くなる、ケース内径の小さな筒状ケースタイプ合金型温度ヒューズに特に有効である。また、定格電流が５Ａ以上と高くされる筒状ケースタイプ合金型温度ヒューズに特に有効である。
【００３２】
本発明において、（リード導体の外径）／（ケース内径）の比を０．６０〜０．９０とする理由は、単に通電時動作温度を高めることにとどまらず、０．６０〜０．９０とすることにより、筒状ケースタイプ合金型温度ヒューズのリード導体引っ張り強度を従来品に較べて飛躍的に向上させることにある。このリード導体引っ張り強度の向上は、リード導体と筒状ケース間の間隙が接着剤の毛管現象に基づく浸透に適合した厚みとなってその間の接着面積が広くされること、接着剤層の薄肉化により接着剤自体の強度よりも接着強度がアップされる３次元的応力効果が効果的に発揮されること等により達成される。また、接着面積の広大化、接着剤層の薄肉化により封止性がアップされ、エージング特性及びヒートサイクル特性が向上される結果、より幅広い環境下での使用が可能となるる。
【００３３】
本発明において、（可溶合金片の外径）／（ケース内径）の比を０．５９〜０．８０とする理由は、０．５９未満では、前記した通電下での動作温度を実質的に非通電下の動作温度（カットオフ温度）に充分に近づけることが難しく本発明の目的を満足に達成することが困難であり、０．８０を超えると筒状ケース内の残存スペースが狭くなり過ぎ溶融合金の球状化分断を円滑に促進し難くなって動作遅れが招来されるからである。
【００３４】
本発明において、可溶合金片接続部分のリード導体外径を可溶合金片外径の１．０５倍以上とすることが好ましい。１．０５倍未満では、接続時に可溶合金片端部に顕著にコブが形成され、このコブのために前記した筒状ケースの挿通に支障をきたす畏れがある。
【００３５】
本発明は、筒状ケース内径が１．３±０．１ｍｍφ〜０．７０±０．１ｍｍφに好適に適用される。
【００３６】
【実施例】
以下の実施例及び比較例において、フラックスにはロジンを主成分とするものを使用し、接着剤にはシリカ入りの二液常温硬化型エポキシ樹脂を使用した。
また、試料数を５０箇とし、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、ヒューズエレメント溶断による通電遮断時のオイル温度を測定し、これら測定値の平均値を通電電流が実質的に０のときの動作温度（カットオフ温度）とした。
また、試料数を５０箇とし、オーブン内において試料を端子台に取付け、試料外面を無風状態とするように試料を覆いで包囲し、各試料にほぼ直流８Ａを３０分間通電して昇温飽和させた状態でオーブン内温度を６０℃から１℃／１０分の速度で昇温し、各試料が動作したときの各試料のサンプル周囲温度を測定し、５０個の測定値の平均値を高電流通電動作温度とした。
【００３７】
〔実施例１〕
図３に示した筒状ケースタイプ合金型温度ヒューズであり、絶縁筒１に内径１．０ｍｍφ、長さ４．０ｍｍのセラミックス筒を使用し、可溶合金片３には外径がケース内径に対し０．６５倍（０．６５ｍｍφ）、長さが２．６ｍｍ、融点が１３５℃の合金を使用し、リード導体２には外径がケース内径に対し０．７０倍（０．７０ｍｍφ）で先端に外径０．８５ｍｍφの鍔を有する銅導体を使用した。
カットオフ温度は１３５℃であり、８Ａ通電動作温度は９８℃であった。
【００３８】
〔実施例２〕
実施例１に対し、可溶合金片外径をケース内径１．０ｍｍφに対し０．５０倍（０．５０ｍｍφ）とした以外、実施例１に同じとした。従って、リード導体外径はケース内径に対し０．７０倍（０．７０ｍｍφ）である。
カットオフ温度は１３５℃であり、８Ａ通電動作温度は９１℃であった。
【００３９】
〔実施例３〕
実施例１に対し、リード導体外径をケース内径に対し０．５３倍（０．５３ｍｍφ）とした以外、実施例１に同じとした。従って、可溶合金片外径はケース内径に対し０．６５倍（０．６５ｍｍφ）である。
カットオフ温度は１３５℃であり、８Ａ通電動作温度は７３℃であった。
【００４０】
〔実施例４〕
実施例１に対し、可溶合金片外径をケース内径に対し０．７０倍（０．７０ｍｍφ）とした以外、実施例１に同じとした。従って、リード導体外径はケース内径に対し０．７０倍（０．７０ｍｍφ）である。
カットオフ温度は１３５℃であり、８Ａ通電動作温度は１０３℃であった。
【００４１】
〔実施例５〕
実施例１に対し、可溶合金片外径をケース内径に対し０．６２倍（０．６２ｍｍφ）とし、リード導体外径をケース内径に対し０．６０倍（０．６０ｍｍφ）とした以外、実施例１に同じとした。
カットオフ温度は１３５℃であり、８Ａ通電動作温度は７８℃であった。
【００４２】
〔比較例〕
実施例１に対し、可溶合金片外径をケース内径１．０ｍｍφに対し０．５０倍（０．５０ｍｍφ）とし、リード導体外径をケース内径に対し０．５３倍（０．５３ｍｍφ）とした以外、実施例１に同じとした。
カットオフ温度は１３５℃であり、８Ａ通電動作温度は６８℃であった。
【００４３】
実施例２が比較例よりも８Ａ通電動作温度が高い理由は、比較例に較べ（リード導体外径）／（ケース内径）の比を大きくしているから、前記の式（３）において、可溶合金片ジュール発生熱のリード導体を経ての流出率αを大きくできリード導体ジュール発生熱の可溶合金片への伝達率βが増しても流出率αの増加によりｋ（１−α）（１／ｄ）^２〕を減少できること、及びリード導体外径ｄ’の増大により１／ｄ’^２を低減できることにより、式（３）の第２項を減少できた結果、通電電流ｉが８Ａと大きくても、８Ａ通電動作温度（Ｔｍ１）をカットオフ温度Ｔｍ０に充分に近づけることができたからである。
【００４４】
実施例３が比較例に較べて８Ａ通電動作温度が比較例よりも高い理由は、（可溶合金片外径）／（ケース内径）の比を大きくしているから、式（３）においてｄを大にしてｋ（１−α）（１／ｄ）^２を小にし、式（３）の第２項を減少できた結果、８Ａ通電動作温度（Ｔｍ１）をカットオフ温度Ｔｍ０に近づけることができたからである。
【００４５】
実施例２では（可溶合金片外径）／（ケース内径）の比を比較例と同じ０．５０とし、（リード導体外径）／（ケース内径）の比を比較例０．５３の０．１７増しである０．７にし、実施例３は（リード導体外径）／（ケース内径）の比を比較例と同じ０．５３とし、（可溶合金片外径）／（ケース内径）の比を比較例０．５０の０．１５増しである０．６５にしているが、実施例２の方が８Ａ通電動作温度のカットオフ温度への接近程度が良く、従って、同程度の比率で太さを変える場合は、可溶合金片よりもリード導体を優先して太くした方が通電時動作温度を高くできることが明かである。
【００４６】
実施例５と実施例３とを比較すると、実施例５の方がカットオフ温度への接近程度が良好である。これは実施例５では、実施例３に較べて（可溶合金片外径）／（ケース内径）の比が０．０３だけ小さいが、（リード導体外径）／（ケース内径）の比が０．０７だけ大きく、可溶合金片径の増加よりもリード導体外径の増加の方が強く効いた結果である。
【００４７】
実施例１や実施例４や実施例５が比較例に較べて８Ａ通電動作温度が高い理由は、比較例に較べ（リード導体外径）／（ケース内径）の比と（可溶合金片外径）／（ケース内径）の比とを共に大きくしているから、上記したｄの増加及びｄ’の増加に基づく式（３）の第２項の低減効果を併せて発揮させ得た結果、温度ヒユーズの動作温度Ｔｘ１をカットオフ温度Ｔｍ０に近づけることができたからであり、その８Ａ通電動作温度のカットオフ温度への接近程度が実施例２や実施例３よりも良い理由は、相乗効果に依存している。
【００４８】
実施例４の８Ａ通電動作温度のカットオフ温度への接近程度が実施例１よりも良い理由は、可溶合金片の外径増大度が大きく、可溶合金片外径増大効果がそれだけ大きく現れた結果である。
【００４９】
上記の実施例から明らかな通り、本発明によれば、筒状ケースタイプ温度ヒユーズの通電時動作温度をケース外径を元のままにして高くできる。
【００５０】
上記実施例２〔（リード導体外径）／（ケース内径）の比０．７〕と比較例〔同０．５３〕とにつき、試料数を５０箇とし、両リード導体をケース端から２０ｍｍの位置でチャッキングし、試料表面温度が安定した後２０ｍｍ／分にて引っ張り強度を測定する試験を温度２５℃及び１２０℃に対し行ったところは、温度２５℃に対し実施例２が９３．５Ｎであるのに対し比較例が３７．５Ｎ、温度１２０℃に対し実施例２が４３．４Ｎであるのに対し比較例が２２．６Ｎであり、請求項１に基づくリード導体引っ張り強度の向上効果が確認できた。
試験後、これらの実施例２及び比較例を解体して接着剤の浸透状態を調査したところ、実施例２ではリード導体先端の鍔にまで達していたものが５０箇中２８箇も認められたが、比較例では０箇であり、リード導体引っ張り強度の向上効果が接着剤の浸透性によることを確認できた。鍔を越えたものは観られず、鍔が接着剤の可溶合金片への入り込み防止に寄与していることも明かになった。
【００５１】
〔実施例６〕
実施例１に対し、リード導体の鍔を省略した以外実施例１に同じとした。従って、絶縁筒内径が１．０ｍｍφ、可溶合金片外径がケース内径に対し０．６５倍（０．６５ｍｍφ）、リード導体外径がケース内径に対し０．７０倍（０．７０ｍｍφ）であり、リード導体外径が可溶合金片外径の１．０８倍である。試料５０箇の全てにおいて、ケースをスムーズに挿通できた。
【００５２】
〔実施例７〕
実施例４に対し、リード導体の鍔を省略した以外実施例４に同じとした。従って、絶縁筒内径が１．０ｍｍφ、可溶合金片外径がケース内径に対し０．７０倍（０．７０ｍｍφ）、リード導体外径がケース内径に対し０．７０倍（０．７０ｍｍφ）であり、リード導体外径が可溶合金片外径の１．００倍である。試料５０箇中の３１箇にコブにケース端がひっかかってケースのスムーズな挿通に支障となった。
この実施例６と７との比較からも、請求項６の効果を確認できる。
【００５３】
【発明の効果】
本発明によれば、筒状ケースタイプ合金型温度ヒューズのケース径を小サイズにしても、高電流通電下での動作温度をヒューズエレメント融点に充分に接近させることができる。従って、本発明によれば、筒状ケースタイプ合金型温度ヒューズをその作動性を良好に保持しつつ小型化できる。
また、比抵抗値の高い鉛フリー合金をヒューズエレメントとしても、高電流通電下での動作温度をヒューズエレメント融点に充分に接近させることができ、筒状ケースタイプ合金型温度ヒューズのヒューズエレメントの鉛フリー化に有益である。
【００５４】
特に、請求項１によれば、リード導体引き抜き強度を向上でき、筒状ケースタイプ合金型温度ヒューズの機械的強度アップや作動時の耐内圧強度アップを図ることができる。更に、請求項２での可溶合金片の外径増大上限の制約下、請求項１との結合で高電流通電下での動作温度をヒューズエレメント融点に著しく接近させ得、上記作動性保証と小型化をよりよく達成できる。
【図面の簡単な説明】
【図１】本発明に係る筒状ケースタイプ合金型温度ヒューズの一実施例を示す図面である。
【図２】本発明に係る筒状ケースタイプ合金型温度ヒューズの上記とは別の実施例を示す図面である。
【図３】本発明に係る筒状ケースタイプ合金型温度ヒューズの上記とは別の実施例を示す図面である。
【図４】従来例を示す図面である。
【符号の説明】
１絶縁筒
２リード導体
３可溶合金片
４フラックス
５接着剤[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a cylindrical case type alloy type thermal fuse.
[0002]
[Prior art]
Alloy type thermal fuses are widely used as thermoprotectors for electrical equipment.
This alloy-type thermal fuse has a structure in which an alloy having a predetermined melting point is used as a fuse element, a flux is applied to the fuse element, and the flux-coated fuse element is sealed with an insulator. In the thermal fuse, as shown in FIG. 4, a fusible alloy piece 3 'is connected between the lead conductors 2', 2 ', and a flux 4' is applied to cover the fusible alloy piece 3 '. Insulating tube 1 'is inserted across' 2 ', and the gap between each end of insulating tube 1' and each lead conductor 2 'is sealed with adhesive 5'. When the fusible alloy piece 3 'is connected therebetween, a hard lead conductor is pushed into the fusible alloy piece end that has been melt-softened due to the difference in melting point between the two, and the fusible alloy piece end becomes a bump-shaped e. I have.
The operating mechanism of this alloy type thermal fuse is as follows.
An alloy type thermal fuse is placed in thermal contact with the electrical equipment to be protected. When the electrical equipment generates heat due to some abnormality, the generated heat melts the fuse element of the thermal fuse, and in the coexistence with the already-melted flux, the molten alloy is divided into spheroids by wetting the lead conductors. As a result, the cutoff of the molten alloy is solidified and the non-return cut-off is terminated.
[0003]
Thus, the temperature fuse is operated at the ambient temperature of the temperature fuse when the temperature of the fusible alloy piece reaches the melting point Tm, that is, at the device temperature (Tx). That is, the temperature fuse is operated when the device temperature reaches the temperature Tx.
More specifically, assuming that the resistance of the fusible alloy piece is R, the resistance of the lead conductor is R ', and the current flowing through the fusible alloy piece is i, the Joule heat generated by the fusible alloy piece is i ² R, Joule generated heat of the lead conductor is i ² Α 'is the amount of heat that flows out of the fusible alloy piece Joule generated heat through the lead conductor. ² R (α <1), the amount of heat transmitted to the fusible alloy piece among the heat generated by the lead conductor Joule is βi ² R ′ (β <1), a coefficient (thermal resistance) involved in raising the temperature of the fusible alloy piece based on the amount of heat flowing out from the fusible alloy piece to the surroundings, h, the temperature of the fusible alloy piece, Ty, the ambient temperature Is Tx,
[0004]
(Equation 1)
Ty = [(1-α) R + βR ′] i ² ・ H + Tx (1)
Holds.
The operating temperature Tx1 of the temperature fuse is given by the ambient temperature Tx when the fusible alloy piece temperature Ty becomes the melting point Tm of the fusible alloy,
[0005]
(Equation 2)
Tx1 = Tm-[(1-α) R + βR ′] i ² ・ H (2)
Holds.
When the energizing current i is substantially 0, the temperature fuse operates when the ambient temperature Tx substantially reaches the melting point of the fusible alloy piece, and the ambient temperature Tx0 at this time is called an operating temperature (cutoff temperature). ing.
[0006]
In the above, if the diameter of the fusible alloy piece is d and the diameter of the lead conductor is d ', the resistance R of the fusible alloy piece is 1 / d ² And the resistance R 'of the lead conductor is 1 / d' ² Therefore, the operating temperature at the time of energization of the above equation (2) is
[0007]
[Equation 3]

(Where k and k 'are constants determined by the specific resistance and length of the fusible alloy piece, the specific resistance and length of the lead conductor, etc.).
[0008]
Thus, when the second term of the equation (3) cannot be neglected, particularly when the wire diameter d of the fusible alloy piece is small and its resistance is high or the current i is large, the temperature is considerably lower than the cutoff temperature Tx0. The temperature fuse is operated at Tx1, and therefore, the temperature fuse is operated at a temperature lower than the temperature at which the equipment is in a dangerous state.
[0009]
Therefore, even if the rated current continues to flow for 7 days, the thermal fuse does not operate. The maximum temperature of the outer surface of the thermal fuse is defined as a holding temperature, and a standard operating at a temperature lower than the holding temperature is defined as a defective product. (Eg, ANSI UL standard).
The holding temperature (TF) is equal to the ambient temperature (Tx1) of the thermal fuse when the rated current is flowing.
(Equation 4)
Tx1 = HTF (4)
(Where H is a coefficient determined by the thermal resistance between the surface of the thermal fuse and the surroundings). Generally, if Tx1 can be increased, TF will also be increased.
[0010]
Table 1 shows the standards obtained for the cylindrical case-type alloy type thermal fuses manufactured and sold by the applicant whose dimensions shown in FIG. 4 are as shown in Table 1, and their electrical ratings are 7 A and 125 V. Has passed the cut-off temperature and the holding temperature shown in Table 1. The product 213 guarantees the operating temperature of 126 ± 3 ° C., and guarantees the non-operation at 102 ° C. or less under the rated current supply. The product 215 guarantees an operating temperature of 145 ± 2 ° C., and guarantees non-operation at 123 ° C. or less under a rated current.
[Table 1]

[0011]
In addition to the cylindrical case type alloy type thermal fuse illustrated above, in the conventional cylindrical case type alloy type thermal fuse, the outer diameter of the fusible alloy piece is set to 0.58 or less of the inner diameter of the cylindrical case, and the outer diameter of the lead conductor is reduced. By setting the diameter to 0.59 or less of the inner diameter of the cylindrical case, the remaining space (the flux is also included in the remaining space) in the case space is considerably widened.
The reason largely depends on the results and experience. However, the remaining space in the case is widened to facilitate the spheroidization of the molten alloy (for example, see Patent Document 1), or the remaining space in the case is widened. There is also disclosed a technical idea of reducing the density of metal vapor generated when the molten alloy is divided to quickly extinguish the arc (for example, see Patent Document 2).
[0012]
[Patent Document 1]
JP-A-58-120541
[Patent Document 2]
JP-A-10-12111
[0013]
[Problems to be solved by the invention]
In recent years, the size of the temperature fuse has been reduced as the size of equipment has been reduced, and a small-sized cylindrical case type temperature fuse with an inner diameter of the cylindrical case of 1.3 ± 0.1 mm to 0.7 ± 0.1 mm has been developed. Is being done.
However, in such a small-sized cylindrical case-type temperature fuse, the ratio of (outer diameter of fusible alloy piece) / (inner diameter of case) or the ratio of (outer diameter of lead conductor) / (inner diameter of case) is set to 0. If the temperature is 58 or less or 0.59 or less, the holding temperature must be set extremely lower than the cut-off temperature, and the temperature fuse operates even though the device is still in a sufficiently safe temperature state. In some cases, the equipment cannot be thermally protected satisfactorily. This situation is a problem that must be solved in reducing the size of the cylindrical case-type alloy thermal fuse.
[0014]
In recent years, the trend of emphasizing environmental preservation has been accelerated, and it has been attempted to eliminate the use of fuse elements that do not contain elements harmful to biological systems such as Pb and Cd even in thermal fuses. For example, In-Sn-Bi alloys The use of a fuse element is under consideration.
However, this In-Sn-Bi alloy or the like has a high specific resistance value, and the holding temperature must be set extremely lower than the cutoff temperature, so that the equipment is still in a sufficiently safe temperature state. There is a concern that the temperature fuse may operate and the device may not be sufficiently thermally protected.
[0015]
In order to increase the operating temperature (Tx1) during energization, it is effective to increase the diameter of the fusible alloy piece and decrease the resistance value R of the fusible alloy piece. However, in the conventional technique in which the outer diameter of the fusible alloy piece is set to 0.58 or less of the inner diameter of the cylindrical case, the outer diameter of the case becomes large, and it is not possible to guarantee the miniaturization of the thermal fuse.
On the other hand, it is conceivable to reduce the resistance value R of the fusible alloy piece by increasing the outer diameter of the fusible alloy piece while keeping the inner diameter of the cylindrical case as it is. For the purpose of securing, the increase in the diameter of the fusible alloy piece is restricted, and this means alone has a limit in solving the above-mentioned problems.
[0016]
By the way, by increasing the lead conductor diameter of the cylindrical case type alloy type thermal fuse, it is possible to increase the outflow rate α of the fusible alloy piece joule generated heat through the lead conductor, and also reduce the lead conductor joule generated heat, Not only is it effective to bring the operating temperature TX1 of the temperature fuse of the equation (3) during energization close to the cut-off temperature, but according to the results of diligent studies by the present inventor, the lead conductor pull of the tubular case type alloy type thermal fuse has been found. Strength can be dramatically improved.
[0017]
SUMMARY OF THE INVENTION An object of the present invention is to make it possible to set the holding temperature of a cylindrical case type alloy type thermal fuse to be high, to improve the tensile strength of the lead conductor of the cylindrical case type alloy type thermal fuse, and to further improve the case inner diameter by 1 mm. It is an object of the present invention to reduce the size to 0.3 ± 0.1 mm to 0.7 ± 0.1 mm while guaranteeing a sufficiently high operating temperature during energization.
A further object of the present invention is to make it possible to set the holding temperature of a cylindrical case type alloy type thermal fuse to a high value even when a lead-free alloy having a high specific resistance value is used as a fuse element. The tensile strength of the lead conductor of the alloy type thermal fuse has been improved, and downsizing such as the case inner diameter of 1.3 ± 0.1mm to 0.7 ± 0.1mm has been made possible while guaranteeing a sufficiently high operating temperature during energization. Is to do.
[0018]
[Means for Solving the Problems]
In the cylindrical case type alloy type thermal fuse according to claim 1, a fusible alloy piece is connected between the lead conductors, a flux is applied to cover the fusible alloy piece, and an insulating cylinder is inserted across the lead conductor. In the temperature fuse in which the gap between each end of the insulating cylinder and each lead conductor is sealed with an adhesive, the outer diameter of the lead conductor is 0.60 to 0.90 times the inner diameter of the insulating cylinder, preferably 0.66 to 0.95. It is characterized by being 0.90 times.
[0019]
In the tubular case type alloy type thermal fuse according to claim 2, a fusible alloy piece is connected between the lead conductors, a flux is applied to cover the fusible alloy piece, and an insulating cylinder is inserted across the lead conductor. The outer diameter of the fusible alloy piece is 0.59 to 0.80 times the inner diameter of the insulating cylinder, preferably 0.1 mm, in a temperature fuse in which the gap between each end of the insulating cylinder and each lead conductor is sealed with an adhesive. It is characterized in that it is 60 to 0.80 times.
[0020]
In the cylindrical case type alloy type thermal fuse according to claim 3, a fusible alloy piece is connected between the lead conductors, a flux is applied to cover the fusible alloy piece, and an insulating cylinder is inserted across the lead conductor. The outer diameter of the fusible alloy piece is 0.59 to 0.80 times the inner diameter of the insulating cylinder, preferably 0.1 mm, in a temperature fuse in which the gap between each end of the insulating cylinder and each lead conductor is sealed with an adhesive. The outer diameter of the lead conductor is 0.60 to 0.90 times, preferably 0.66 to 0.90 times the inner diameter of the insulating tube.
[0021]
The cylindrical case type alloy type thermal fuse according to claim 4, wherein a flange is provided on each lead conductor, and each end of the fusible alloy piece is connected to the flange. Is a cylindrical case type alloy type thermal fuse.
[0022]
The cylindrical case type alloy type thermal fuse according to claim 5 is the cylindrical case type alloy type thermal fuse according to any one of claims 1 to 4, wherein the inner diameter of the insulating cylinder is 1.4 mm to 0.6 mm. .
[0023]
The tubular case type alloy-type thermal fuse according to claim 6, wherein the outer diameter of the lead conductor at the connection portion of the fusible alloy piece is 1.05 times or more the outer diameter of the fusible alloy piece. 5. The tubular case-type alloy-type thermal fuse according to any one of 5.
[0024]
In the cylindrical case type alloy-type thermal fuse according to claim 7, the fusible alloy pieces are made of an In-Sn-Bi-based alloy, a Bi-Sn-Sb-based alloy, an In-Sn-based alloy, an In-Bi-based alloy, and a Bi-based alloy. 7. The tubular case-type alloy type thermal fuse according to claim 1, wherein the thermal fuse is any one of an Sn-based alloy and an In-based alloy.
[0025]
In the cylindrical case type alloy type thermal fuse according to claim 8, the composition of the In-Sn-Bi-based alloy is as follows: (1) 43% <Sn ≤ 70%, 0.5% ≤ In ≤ 10%, residual Bi, ( 2) 25% ≦ Sn ≦ 40%, 50% ≦ In ≦ 55%, residual Bi, (3) 25% <Sn ≦ 44%, 55% <In ≦ 74%, 1% ≦ Bi <20%, (4 ) 46% <Sn ≦ 70%, 18% ≦ In <48%, 1% ≦ Bi ≦ 12%, (5) 5% ≦ Sn ≦ 28%, 15% ≦ In <37%, remaining Bi (Bi57 (5%, In25.2%, Sn17.3% and Bi54%, In29.7%, Sn16.3%, respectively, except for the ranges of Bi ± 2%, In and Sn ± 1%), (6) ) 10% ≦ Sn ≦ 18%, 37% ≦ In ≦ 43%, residual Bi, (7) 25% <Sn ≦ 60%, 20% ≦ In <50%, 12 % <Bi ≦ 33%, (8) One or more of Ag, Au, Cu, Ni, Pd, Pt, Sb, Ga, Ge, P in 100 parts by weight of any of (1) to (7) (9) 33% ≦ Sn ≦ 43%, 0.5% ≦ In ≦ 10%, residual Bi, (10) 47% ≦ Sn ≦ 49%, 51% ≦ In 3 to 5 parts by weight of Bi are added to 100 parts by weight of ≦ 53%, (11) 40% ≦ Sn ≦ 46%, 7% ≦ Bi ≦ 12%, remaining In, (12) 0.3% ≦ Sn ≦ 1.5%, 51% ≦ In ≦ 54%, remaining Bi, (13) 2.5% ≦ Sn ≦ 10%, 25% ≦ Bi ≦ 35%, remaining In, (14) (9) to (13) (1) Ag, Au, Cu, Ni, Pd, Pt, Sb, Ga, Ge, P or a total of 0.01 to 7 parts by weight is added to any one of 100 parts by weight. ≦ Sn ≦ 25%, 48% ≦ In ≦ 60%, 100 parts by weight of residual Bi, one or more of Ag, Au, Cu, Ni, Pd, Pt, Sb, Ga, Ge, and P in total 0 0.01 to 7 parts by weight, the composition of the Bi-Sn-Sb-based alloy is (16) 30% ≤ Sn ≤ 70%, 0.3% ≤ Sb ≤ 20%, the remaining Bi, (17) 100 of (16) One or more of Ag, Au, Cu, Ni, Pd, Pt, Ga, Ge, and P are added to the parts by weight in a total amount of 0.01 to 7 parts by weight, and the composition of the In-Sn-based alloy is (18) 52. % ≦ In ≦ 85%, balance Sn, 100 parts by weight of (19) and (18) and one or more of Ag, Au, Cu, Ni, Pd, Pt, Sb, Ga, Ge, and P in total 0 0.01 to 7 parts by weight, the composition of the In—Bi alloy is (20) 45% ≦ Bi ≦ 55%, the remaining In, (21) (2 )), A total of 0.01 to 7 parts by weight of one or more of Ag, Au, Cu, Ni, Pd, Pt, Sb, Ga, Ge, and P is added to 100 parts by weight of the composition; (22) 50% <Bi ≦ 56%, residual Sn, (23) one or more of Ag, Au, Cu, Ni, Pd, Pt, Ga, and Ge in 100 parts by weight of (22) 0.01 to 7 parts by weight in total, and the composition of the In-based alloy is (24) In 100 parts by weight of In, one or more of Au, Bi, Cu, Ni, Pd, Pt, Ga, Ge, and P. (25) 90% ≦ In ≦ 99.9%, 0.1% ≦ Ag ≦ 10% to 100 parts by weight of Au, Bi, Cu, Ni, Pd, Pt, , Ga, Ge, P or a total of 0.01 to 7 parts by weight of (26) 95% ≦ In ≦ 99 0.9%, 0.1% ≦ Sb ≦ 5%, 100 parts by weight of Au, Bi, Cu, Ni, Pd, Pt, Ga, Ge, P or a total of 0.01 to 7% by weight. 8. The method according to claim 7, wherein the addition is any of the following:
Is a cylindrical case type alloy type thermal fuse.
[0026]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a longitudinal sectional view showing one embodiment of the cylindrical case type alloy type thermal fuse according to the first aspect.
In FIG. 1, reference numeral 1 denotes a cylindrical case made of a material having excellent heat resistance, heat conductivity and insulation properties, for example, a ceramic.

Reference numerals

2 and 2 denote lead conductors having a circular cross section, and reference numeral 21 denotes a flange provided at the tip of the lead conductor. This collar can be omitted. Reference numeral 3 denotes a fusible alloy piece having a circular cross section connected between the

lead conductors

2 and 2 by welding or the like, and 4 denotes a flux applied over the

lead conductors

2 and 2 to cover the fusible alloy piece 3. Reference numeral 5 denotes an adhesive that seals between each end of the cylindrical case 1 and the lead conductor 2, and for example, an epoxy resin containing a filler can be used.
In FIG. 1, the ratio of (outer diameter of lead conductor) / (inner diameter of case) is set to 0.60 to 0.90, preferably 0.66 to 0.90, and (outer diameter of fusible alloy piece) / (inner diameter of case). Is set to 0.58 or less as in the past.
[0027]
FIG. 2 is a longitudinal sectional view showing an embodiment of the cylindrical case type alloy type thermal fuse according to the second aspect.
In FIG. 2, reference numeral 1 denotes a cylindrical case made of a material excellent in heat resistance, heat conductivity, and insulation, such as ceramic, as described above,

reference numerals

2 and 2 denote lead conductors having a circular cross section, and reference numeral 21 denotes a lead conductor tip. Flange 3 is a fusible alloy piece having a circular cross section connected between

lead conductors

2 and 2 by welding or the like, 4 is a flux covering fusible alloy piece 3 and applied over

lead conductors

2 and 5, and 5 is a cylindrical case 1. An adhesive such as an epoxy resin containing a filler that seals between each end and the lead conductor 2.
In FIG. 2, the ratio of (outer diameter of fusible alloy piece) / (inner diameter of case) is 0.59 to 0.80, preferably 0.60 to 0.80, and (outer diameter of lead conductor) / (inner diameter of case) ) Is set to 0.59 or less as before.
[0028]
FIG. 3 is a longitudinal sectional view showing an embodiment of the cylindrical case type alloy type thermal fuse according to the third aspect.
In FIG. 3, reference numeral 1 denotes a cylindrical case made of a material having excellent heat resistance, heat conductivity and insulation properties, for example, a ceramic.

Reference numerals

2 and 2 denote lead conductors having circular cross sections, each of which is provided with a flange 21 at the front end, similarly to the above. Reference numeral 3 denotes a fusible alloy piece having a circular cross section connected between the

lead conductors

2 and 2 by welding or the like, and a flux 4 is applied over the

lead conductors

2 and 2 so as to cover the fusible alloy piece 3. Reference numeral 5 denotes an adhesive that seals between each end of the cylindrical case 1 and the lead conductor 2, for example, an epoxy resin containing a filler.
In FIG. 3, the ratio of (outer diameter of lead conductor) / (inner diameter of case) is set to 0.60 to 0.90, preferably 0.66 to 0.90, and (outer diameter of fusible alloy piece) / (inner diameter of case) ) Is 0.59 to 0.80, preferably 0.60 to 0.80.
In the above description, the outer diameter of the fusible alloy piece 3 and the outer diameter of the lead conductor 2 are different, but they may be equal.
[0029]
As the fusible alloy piece 3, an alloy having a predetermined melting point that can correspond to a required cutoff temperature is used.
Soluble alloy pieces that do not contain harmful elements to biological systems for environmental protection, such as In-Sn-Bi-based alloys, Bi-Sn-Sb-based alloys, In-Sn-based alloys, In-Bi-based alloys, Bi- It is preferable to use alloy pieces of a Sn-based alloy and an In-based alloy.
[0030]
The composition of the In—Sn—Bi alloy is as follows: (1) 43% <Sn ≦ 70%, 0.5% ≦ In ≦ 10%, residual Bi, (2) 25% ≦ Sn ≦ 40%, 50% ≦ In ≦ 55%, residual Bi, (3) 25% <Sn ≦ 44%, 55% <In ≦ 74%, 1% ≦ Bi <20%, (4) 46% <Sn ≦ 70%, 18% ≦ In <48%, 1% ≦ Bi ≦ 12%, (5) 5% ≦ Sn ≦ 28%, 15% ≦ In <37%, residual Bi (however, Bi57.5%, In25.2%, Sn17.3% And Bi 54%, In 29.7% and Sn 16.3%, respectively, excluding the ranges of Bi ± 2%, In and Sn ± 1%), (6) 10% ≦ Sn ≦ 18%, 37% ≦ In ≦ 43%, residual Bi, (7) 25% <Sn ≦ 60%, 20% ≦ In <50%, 12% <Bi ≦ 33%, (8) What is (1) to (7) One or more of Ag, Au, Cu, Ni, Pd, Pt, Sb, Ga, Ge and P are added to 100 parts by weight in total of 0.01 to 7 parts by weight. (9) 33% ≦ Sn ≦ 43%, 0.5% ≦ In ≦ 10%, residual Bi, (10) 47% ≦ Sn ≦ 49%, 51% ≦ In ≦ 53%, 100 parts by weight of Bi and 3 to 5 parts by weight of Bi are added, (11) 40% ≦ Sn ≦ 46%, 7% ≦ Bi ≦ 12%, residual In, (12) 0.3% ≦ Sn ≦ 1.5%, 51% ≦ In ≦ 54%, residual Bi, (13 ) 2.5% ≦ Sn ≦ 10%, 25% ≦ Bi ≦ 35%, balance In, (14) Ag, Au, Cu, Ni, Pd, Pt in 100 parts by weight of any of (9) to (13) , Sb, Ga, Ge, P, one or more of 0.01 to 7 parts by weight in total, (15) 10% ≦ Sn ≦ 25%, 48% ≦ In ≦ 60%, balance Ag i to 100 parts by weight, Au, Cu, Ni, Pd, Pt, Sb, Ga, Ge, etc. have been added total of 0.01 to 7 parts by weight of one or more of the P can be used.
The composition of the Bi-Sn-Sb-based alloy is as follows: (16) 30% ≦ Sn ≦ 70%, 0.3% ≦ Sb ≦ 20%, balance Bi, (17) Ag, Au in 100 parts by weight of (16). , Cu, Ni, Pd, Pt, Ga, Ge, P, or a total of 0.01 to 7 parts by weight.
The composition of the In—Sn based alloy is as follows: (18) 52% ≦ In ≦ 85%, balance Sn, (19) 100 parts by weight of (18), Ag, Au, Cu, Ni, Pd, Pt, Sb, Ga , Ge and P are added in total of 0.01 to 7 parts by weight, and the composition of the In—Bi alloy is (20) 45% ≦ Bi ≦ 55%, the remaining In, (21) (20) A composition obtained by adding one or more of Ag, Au, Cu, Ni, Pd, Pt, Sb, Ga, Ge, and P to a total of 0.01 to 7 parts by weight to 100 parts by weight of the composition described above can be used.
The composition of the Bi-Sn-based alloy is as follows: (22) 50% <Bi ≦ 56%, balance Sn, (23) 100 parts by weight of (22), Ag, Au, Cu, Ni, Pd, Pt, Ga, Ge One or two or more of these may be added in a total amount of 0.01 to 7 parts by weight.
As the composition of the In-based alloy, one or more of Au, Bi, Cu, Ni, Pd, Pt, Ga, Ge, and P are added in total of 0.01 to 7 parts by weight to 100 parts by weight of In. (25) One kind of Au, Bi, Cu, Ni, Pd, Pt, Ga, Ge, P in 100 parts by weight of 90% ≦ In ≦ 99.9%, 0.1% ≦ Ag ≦ 10% Or a total of 0.01 to 7 parts by weight of two or more kinds, (26) Au, Bi, Cu, Ni, 100% by weight of 95% ≦ In ≦ 99.9%, 0.1% ≦ Sb ≦ 5% It is possible to use one or more of Pd, Pt, Ga, Ge, and P added in a total amount of 0.01 to 7 parts by weight.
As the lead conductor 3, a copper conductor, a tin-plated copper conductor, or the like can be used.
The flux 4 usually has a melting point lower than that of the fuse element. 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, a natural rosin, a modified rosin (for example, hydrogenated rosin, disproportionated rosin, polymerized rosin) or a purified rosin thereof is used as the rosin. Organic acids such as diethylamine hydrochloride, hydrobromide and adipic acid can be used as the activator.
As the adhesive 5, a curable resin containing a filler, preferably a room-temperature curable resin is used. For example, an epoxy resin to which a filler such as alumina, silica, or calcium carbonate is added can be used.
[0031]
INDUSTRIAL APPLICABILITY The present invention is particularly effective for a cylindrical case-type alloy type thermal fuse having a small case inner diameter, in which the resistance value of the fusible alloy piece is increased due to the thinning of the fusible alloy piece. Further, the present invention is particularly effective for a cylindrical case type alloy type thermal fuse whose rated current is increased to 5 A or more.
[0032]
In the present invention, the reason why the ratio of (outer diameter of the lead conductor) / (inner diameter of the case) is set to 0.60 to 0.90 is not limited to simply increasing the operating temperature at the time of energization, but to 0.60 to 0.90. Accordingly, the present invention is to dramatically improve the lead conductor tensile strength of a cylindrical case type alloy type thermal fuse as compared with a conventional product. The improvement in the tensile strength of the lead conductor is achieved by making the gap between the lead conductor and the cylindrical case a thickness suitable for the penetration based on the capillary action of the adhesive, thereby increasing the bonding area therebetween, and reducing the thickness of the adhesive layer. Thus, a three-dimensional stress effect in which the adhesive strength is increased more than the strength of the adhesive itself is effectively achieved, and the like. In addition, enlarging the adhesive area and reducing the thickness of the adhesive layer enhances the sealing property, thereby improving the aging characteristics and the heat cycle characteristics. As a result, the device can be used in a wider environment.
[0033]
In the present invention, the reason why the ratio of (outer diameter of fusible alloy piece) / (inner diameter of case) is set to 0.59 to 0.80 is that when the ratio is less than 0.59, the operating temperature under energization is substantially reduced. In addition, it is difficult to sufficiently approach the operating temperature (cut-off temperature) under non-energization, and it is difficult to achieve the object of the present invention satisfactorily. If it exceeds 0.80, the remaining space in the cylindrical case becomes narrow. This is because it is difficult to smoothly promote the spheroidization of the molten alloy, which causes an operation delay.
[0034]
In the present invention, it is preferable that the outer diameter of the lead conductor at the connecting portion of the fusible alloy piece be 1.05 times or more the outer diameter of the fusible alloy piece. If it is less than 1.05 times, a bump is formed remarkably at one end of the fusible alloy at the time of connection, and there is a fear that the bump may hinder the insertion of the cylindrical case.
[0035]
The present invention is suitably applied when the inner diameter of the cylindrical case is 1.3 ± 0.1 mmφ to 0.70 ± 0.1 mmφ.
[0036]
【Example】
In the following Examples and Comparative Examples, a flux containing rosin as a main component was used as a flux, and a two-part cold curing epoxy resin containing silica was used as an adhesive.
In addition, the number of samples was set to 50, and immersed in an oil bath at a heating rate of 1 ° C./min while applying a current of 0.1 amperes, and the oil temperature was measured when the power was cut off by fusing the fuse element. The average value was defined as the operating temperature (cut-off temperature) when the supplied current was substantially zero.
The number of samples was set to 50, the samples were mounted on a terminal block in an oven, and the samples were covered and covered so that the outer surface of the samples was kept in a windless state. In this state, the temperature in the oven was raised at a rate of 1 ° C./10 minutes from 60 ° C., and the ambient temperature of each sample when each sample was operated was measured. The current carrying operation temperature was set.
[0037]
[Example 1]
The cylindrical case type alloy type thermal fuse shown in FIG. 3 uses a ceramic cylinder having an inner diameter of 1.0 mmφ and a length of 4.0 mm for the insulating cylinder 1, and the outer diameter of the fusible alloy piece 3 corresponds to the inner diameter of the case. The alloy used is 0.65 times (0.65 mmφ), 2.6 mm in length and 135 ° C. in melting point. The outer diameter of the lead conductor 2 is 0.70 times (0.70 mmφ) of the inner diameter of the case. A copper conductor having a flange with an outer diameter of 0.85 mmφ at the tip was used.
The cutoff temperature was 135 ° C., and the 8A energizing operating temperature was 98 ° C.
[0038]
[Example 2]
Example 1 was the same as Example 1 except that the outer diameter of the fusible alloy piece was 0.50 times (0.50 mmφ) the case inner diameter 1.0 mmφ. Therefore, the outer diameter of the lead conductor is 0.70 times (0.70 mmφ) the inner diameter of the case.
The cutoff temperature was 135 ° C., and the 8A energizing operating temperature was 91 ° C.
[0039]
[Example 3]
Example 1 was the same as Example 1 except that the outer diameter of the lead conductor was 0.53 times (0.53 mmφ) the inner diameter of the case. Therefore, the outer diameter of the fusible alloy piece is 0.65 times (0.65 mmφ) the inner diameter of the case.
The cutoff temperature was 135 ° C., and the 8A energizing operating temperature was 73 ° C.
[0040]
[Example 4]
Example 1 was the same as Example 1 except that the outer diameter of the fusible alloy piece was 0.70 times (0.70 mmφ) the inner diameter of the case. Therefore, the outer diameter of the lead conductor is 0.70 times (0.70 mmφ) the inner diameter of the case.
The cutoff temperature was 135 ° C., and the 8A energizing operating temperature was 103 ° C.
[0041]
[Example 5]
Compared to Example 1, except that the outer diameter of the fusible alloy piece was 0.62 times (0.62 mmφ) the inner diameter of the case and the outer diameter of the lead conductor was 0.60 times (0.60 mmφ) of the inner diameter of the case. Same as Example 1.
The cutoff temperature was 135 ° C., and the 8A energizing operating temperature was 78 ° C.
[0042]
(Comparative example)
Compared to Example 1, the outer diameter of the fusible alloy piece was 0.50 times (0.50 mmφ) for the case inner diameter of 1.0 mmφ, and the lead conductor outer diameter was 0.53 times (0.53 mmφ) for the case inner diameter. The procedure was the same as in Example 1 except for the above.
The cutoff temperature was 135 ° C., and the 8A energizing operating temperature was 68 ° C.
[0043]
The reason why Example 2 has a higher 8 A energizing operation temperature than the comparative example is that the ratio of (lead conductor outer diameter) / (case inner diameter) is larger than that of the comparative example. The outflow rate α of the heat generated from the molten alloy piece Joule via the lead conductor can be increased, and even if the transfer rate β of the heat generated by the lead conductor Joule to the fusible alloy piece increases, k (1−α) ( 1 / d) ² 1 / d ′ by increasing the outer diameter d ′ of the lead conductor. ² Can be reduced, the second term of the equation (3) can be reduced. As a result, even if the energizing current i is as large as 8 A, the 8 A energizing operating temperature (Tm1) can be sufficiently brought close to the cutoff temperature Tm0. is there.
[0044]
The reason why the 8 A energizing operation temperature in Example 3 is higher than that in the comparative example is that the ratio of (fusible alloy piece outer diameter) / (case inner diameter) is increased. And k (1-α) (1 / d) ² Is reduced, and as a result of reducing the second term of the equation (3), the 8A energizing operation temperature (Tm1) can be made close to the cutoff temperature Tm0.
[0045]
In Example 2, the ratio of (fusible alloy piece outer diameter) / (case inner diameter) was set to 0.50, which is the same as the comparative example, and the ratio of (lead conductor outer diameter) / (case inner diameter) was set to 0 in Comparative Example 0.53. In Example 3, the ratio of (lead conductor outer diameter) / (case inner diameter) was set to 0.53, which is the same as that of the comparative example, and the ratio of (fusible alloy piece outer diameter) / (case inner diameter) was increased by .17. Is set to 0.65, which is 0.15 more than that of the comparative example 0.50. However, in Example 2, the degree of approach of the 8A energizing operation temperature to the cutoff temperature is better, and therefore, the same ratio When the thickness is changed by using the above method, it is clear that the operating temperature during energization can be increased by increasing the thickness of the lead conductor over the fusible alloy piece.
[0046]
Comparing Example 5 with Example 3, Example 5 has a better approach to the cutoff temperature. This is because in Example 5, the ratio of (soluble alloy piece outer diameter) / (case inner diameter) was smaller by 0.03 than in Example 3, but the ratio of (lead conductor outer diameter) / (case inner diameter) was smaller. It is larger by 0.07, which is a result that the increase in the outer diameter of the lead conductor is more effective than the increase in the diameter of the fusible alloy piece.
[0047]
The reason why Example 1, Example 4, and Example 5 have a higher 8 A energizing operating temperature than the comparative example is that the ratio of (lead conductor outer diameter) / (case inner diameter) and (the fusible alloy piece outer) are higher than the comparative example. Since the ratio of (diameter) / (inner diameter of the case) is both increased, the effect of reducing the second term of the equation (3) based on the increase in d and the increase in d ′ described above can also be exhibited. This is because the operating temperature Tx1 of the temperature fuse can be brought close to the cutoff temperature Tm0. The reason why the 8A energization operating temperature approaches the cutoff temperature better than the second and third embodiments is because of the synergistic effect. Depends.
[0048]
The reason why the 8A energizing operation temperature of Example 4 approaches the cutoff temperature better than that of Example 1 is that the degree of increase in the outer diameter of the fusible alloy piece is large, and the effect of increasing the outer diameter of the fusible alloy piece appears so much. It is a result.
[0049]
As is clear from the above embodiment, according to the present invention, the operating temperature during energization of the cylindrical case type temperature fuse can be increased while keeping the case outer diameter unchanged.
[0050]
For Example 2 [ratio of (lead conductor outer diameter) / (case inner diameter) 0.7] and Comparative Example [0.53], the number of samples was 50 and both lead conductors were 20 mm from the case end. After the sample was chucked at the position and the test for measuring the tensile strength at 20 mm / min after the sample surface temperature was stabilized was performed at a temperature of 25 ° C. and 120 ° C., Example 2 was 93.5 N at a temperature of 25 ° C. Whereas, the comparative example is 37.5 N, and the temperature of 120 ° C. is 43.4 N in the example 2 and the comparative example is 22.6 N. The effect of improving the tensile strength of the lead conductor based on claim 1. Was confirmed.
After the test, when these Examples 2 and Comparative Examples were disassembled and the state of penetration of the adhesive was investigated, in Example 2, 28 out of 50 cases that reached the flange at the tip of the lead conductor were recognized. However, in Comparative Example, the number was 0, and it was confirmed that the effect of improving the lead conductor tensile strength was due to the permeability of the adhesive. Nothing over the flange was observed, and it was clarified that the flange contributed to preventing the adhesive from entering the fusible alloy piece.
[0051]
[Example 6]
Example 1 was the same as Example 1 except that the flange of the lead conductor was omitted. Therefore, the inner diameter of the insulating cylinder is 1.0 mmφ, the outer diameter of the fusible alloy piece is 0.65 times (0.65 mmφ) the inner diameter of the case, and the outer diameter of the lead conductor is 0.70 times (0.70 mmφ) the inner diameter of the case. The outer diameter of the lead conductor is 1.08 times the outer diameter of the fusible alloy piece. In all of the 50 samples, the cases could be smoothly inserted.
[0052]
[Example 7]
Example 4 was the same as Example 4 except that the flange of the lead conductor was omitted. Therefore, the inner diameter of the insulating cylinder is 1.0 mmφ, the outer diameter of the fusible alloy piece is 0.70 times (0.70 mmφ) the inner diameter of the case, and the outer diameter of the lead conductor is 0.70 times (0.70 mmφ) the inner diameter of the case. Yes, the outer diameter of the lead conductor is 1.00 times the outer diameter of the fusible alloy piece. The edge of the case stuck to the bump on 31 of 50 samples, which hindered the smooth insertion of the case.
The effect of claim 6 can also be confirmed from the comparison between Examples 6 and 7.
[0053]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, even if the case diameter of a cylindrical case type alloy type thermal fuse is small, the operating temperature under high-current supply can be made to approach a fuse element melting point sufficiently. Therefore, according to the present invention, it is possible to reduce the size of the cylindrical case type alloy type thermal fuse while maintaining good operability.
Even if a lead-free alloy having a high specific resistance value is used as the fuse element, the operating temperature under high-current application can be sufficiently close to the melting point of the fuse element. Useful for free.
[0054]
In particular, according to the first aspect, the lead conductor pull-out strength can be improved, and the mechanical strength of the cylindrical case type alloy type thermal fuse and the internal pressure strength during operation can be improved. Further, under the constraint of the upper limit of the increase in the outer diameter of the fusible alloy piece according to the second aspect, the operating temperature under high-current energization can be made extremely close to the melting point of the fuse element by the combination with the first aspect. Better miniaturization can be achieved.
[Brief description of the drawings]
FIG. 1 is a view showing one embodiment of a tubular case type alloy type thermal fuse according to the present invention.
FIG. 2 is a drawing showing another embodiment of the tubular case type alloy thermal fuse according to the present invention.
FIG. 3 is a drawing showing another embodiment of the cylindrical case type alloy thermal fuse according to the present invention.
FIG. 4 is a drawing showing a conventional example.
[Explanation of symbols]
1 insulating tube
2 Lead conductor
3 fusible alloy pieces
4 flux
5 adhesive

Claims

A fusible alloy piece is connected between the lead conductors, a flux is applied to cover the fusible alloy piece, an insulating cylinder is inserted across the lead conductor, and each end of the insulating cylinder and each lead conductor are bonded. A tubular case-type alloy-type thermal fuse characterized in that the outer diameter of the lead conductor is 0.60 to 0.90 times the inner diameter of the insulating cylinder in the temperature fuse sealed with an agent.

A fusible alloy piece is connected between the lead conductors, a flux is applied to cover the fusible alloy piece, an insulating cylinder is inserted across the lead conductor, and each end of the insulating cylinder and each lead conductor are bonded. A tubular case-type alloy-type thermal fuse characterized in that the outer diameter of a fusible alloy piece is 0.59 to 0.80 times the inner diameter of an insulating cylinder in a temperature fuse sealed with an agent.

A fusible alloy piece is connected between the lead conductors, a flux is applied to cover the fusible alloy piece, an insulating cylinder is inserted across the lead conductor, and each end of the insulating cylinder and each lead conductor are bonded. In the temperature fuse sealed with the agent, the outer diameter of the fusible alloy piece is 0.59 to 0.80 times the inner diameter of the insulating cylinder, and the outer diameter of one lead conductor is 0.60 to 0.60 of the inner diameter of the insulating cylinder. A tubular case type alloy type thermal fuse characterized by being 0.90 times.

4. A tubular case-type alloy-type thermal fuse according to any one of claims 1 to 3, wherein a flange is provided on each lead conductor, and each end of the fusible alloy piece is connected to the flange.

The tubular case-type alloy-type thermal fuse according to any one of claims 1 to 4, wherein the inner diameter of the insulating cylinder is 1.4 mm to 0.6 mm.

The tubular case type alloy type thermal fuse according to any one of claims 1 to 5, wherein the outer diameter of the lead conductor at the connection portion of the fusible alloy piece is 1.05 times or more the outer diameter of the fusible alloy piece. .

The fusible alloy piece is any one of an In-Sn-Bi-based alloy, a Bi-Sn-Sb-based alloy, an In-Sn-based alloy, an In-Bi-based alloy, a Bi-Sn-based alloy, and an In-based alloy. The cylindrical case type alloy type thermal fuse according to any one of claims 1 to 6.

The composition of the In—Sn—Bi-based alloy is (1) 43% <Sn ≦ 70%, 0.5% ≦ In ≦ 10%, residual Bi, (2) 25% ≦ Sn ≦ 40%, 50% ≦ In ≦ (3) 25% <Sn ≦ 44%, 55% <In ≦ 74%, 1% ≦ Bi <20%, (4) 46% <Sn ≦ 70%, 18% ≦ In <48 %, 1% ≦ Bi ≦ 12%, (5) 5% ≦ Sn ≦ 28%, 15% ≦ In <37%, remaining Bi (however, Bi57.5%, In25.2%, Sn17.3% and Bi54 %, In 29.7% and Sn 16.3%, respectively, excluding the ranges of Bi ± 2%, In and Sn ± 1%), (6) 10% ≦ Sn ≦ 18%, 37% ≦ In ≦ 43 %, Residual Bi, (7) 25% <Sn ≦ 60%, 20% ≦ In <50%, 12% <Bi ≦ 33%, (8) Any one of (1) to (7) 100 One or more of Ag, Au, Cu, Ni, Pd, Pt, Sb, Ga, Ge, and P are added to the parts by weight in a total amount of 0.01 to 7 parts by weight. (9) 33% ≦ Sn ≦ 43% , 0.5% ≦ In ≦ 10%, residual Bi, (10) Add 3 to 5 parts by weight of Bi to 100 parts by weight of 47% ≦ Sn ≦ 49%, 51% ≦ In ≦ 53%, (11) 40% ≦ Sn ≦ 46%, 7% ≦ Bi ≦ 12%, residual In, (12) 0.3% ≦ Sn ≦ 1.5%, 51% ≦ In ≦ 54%, residual Bi, (13) 2. 5% ≦ Sn ≦ 10%, 25% ≦ Bi ≦ 35%, balance In, (14) Ag, Au, Cu, Ni, Pd, Pt, Sb, 100 parts by weight in any of (9) to (13) One or more of Ga, Ge and P are added in a total amount of 0.01 to 7 parts by weight, (15) 10% ≦ Sn ≦ 25%, 48% ≦ In ≦ 60%, and the remaining Bi is 10%. A total of 0.01 to 7 parts by weight of one or more of Ag, Au, Cu, Ni, Pd, Pt, Sb, Ga, Ge, and P is added to parts by weight, and the composition of the Bi-Sn-Sb-based alloy is (16) 30% ≦ Sn ≦ 70%, 0.3% ≦ Sb ≦ 20%, residual Bi, (17) Ag, Au, Cu, Ni, Pd, Pt, Ga, Ge in 100 parts by weight of (16) , P is added in an amount of 0.01 to 7 parts by weight in total, and the composition of the In—Sn alloy is (18) 52% ≦ In ≦ 85%, the remaining Sn is (100) of (19) and (18). One part or two or more of Ag, Au, Cu, Ni, Pd, Pt, Sb, Ga, Ge, and P are added to parts by weight in total of 0.01 to 7 parts by weight, and the composition of the In-Bi alloy is (20%). ) 45% ≤ Bi ≤ 55%, balance In, (21), 100 parts by weight of the composition of (20), Ag, Au, Cu, Ni, P , Pt, Sb, Ga, Ge, P, or a total of 0.01 to 7 parts by weight of Bi-Sn based alloy (22) 50% <Bi ≦ 56%, residual Sn, (23) A total of 0.01 to 7 parts by weight of one or more of Ag, Au, Cu, Ni, Pd, Pt, Ga, and Ge is added to 100 parts by weight of (22). (24) A total of 0.01 to 7 parts by weight of one or more of Au, Bi, Cu, Ni, Pd, Pt, Ga, Ge, and P is added to 100 parts by weight of In. (25) 90% ≦ One or two or more of Au, Bi, Cu, Ni, Pd, Pt, Ga, Ge, and P are added to 100 parts by weight of In ≦ 99.9% and 0.1% ≦ Ag ≦ 10% in a total amount of 0.1%. Au, B in 100 parts by weight of (26) 95% ≦ In ≦ 99.9%, 0.1% ≦ Sb ≦ 5% The cylindrical case according to claim 7, wherein one or more of i, Cu, Ni, Pd, Pt, Ga, Ge, and P are added in a total amount of 0.01 to 7 parts by weight. Type alloy type thermal fuse.