JP3754725B2

JP3754725B2 - Flat temperature fuse

Info

Publication number: JP3754725B2
Application number: JP18843495A
Authority: JP
Inventors: 俊朗川西
Original assignee: Uchihashi Estec Co Ltd
Current assignee: Uchihashi Estec Co Ltd
Priority date: 1995-06-30
Filing date: 1995-06-30
Publication date: 2006-03-15
Anticipated expiration: 2021-03-15
Also published as: JPH0917303A

Description

【０００１】
【産業上の利用分野】
本発明は合金型の平型温度ヒュ−ズに関するものである。
【０００２】
【従来の技術】
電気機器・電子機器等を過電流に基づく異常発熱から事前に保護するための温度ヒュ−ズとして、合金型温度ヒュ−ズが周知されている。
周知の通り、合金型温度ヒュ−ズにおいては、所望融点の低融点金属体をフラックスとの共存状態でヒュ−ズエレメントとして使用し、被保護機器の過電流に基づく発生熱で低融点金属体を溶融させ、既溶融フラックスの活性力で低融点金属体の酸化皮膜を除去すると共に溶融フラックスとの共存下での表面張力で低融点金属体の溶融金属の球状化を促し、この球状化の進行で溶融金属を分断させ、この分断に伴い発生するア−クをその後の球状化進行による分断間距離の増加で消滅させることにより機器への通電を遮断している。
【０００３】
合金型温度ヒュ−ズには、各種の形式が使用されているが、絶縁基板に低融点金属体を配設し、該絶縁基板に上記低融点金属体を覆って絶縁外包体を被覆する形式は平型化に有利であり、平型温度ヒュ−ズとして多用されている。
【０００４】
【発明が解決しようとする課題】
上記の合金型温度ヒュ−ズにおいては、フラックスが温度ヒュ−ズの作動に重大に関与する。而るに、温度ヒュ−ズが実際に作動するまでの期間、つまり機器が正常に動作を続ける期間は、通常、年単位の長期であり、この間、温度ヒュ−ズは機器の負荷電流に基づくヒ−トサイクルに曝され、熱応力の繰返し変動を受けるので、フラックスや低融点金属体の材質如何によっては、フラックスの活性力や低融点金属体の表面酸化の度合の変化が招来される。
【０００５】
従来、合金型温度ヒュ−ズを上記したフラックス共存下での溶融低融点金属の表面張力による球状化分断で作動させることに代え、低融点金属体に引張り力または剪断力を作用させておき、低融点金属体が溶融されると、その引張り力または剪断力で低融点金属体を強制的に破断することが公知である。
この強制的作動構造の代表例としては、所定のギャップで離隔した弾性片を強制的に接触させてギャップを零にし、その接触点を低融点金属体で固着し、低融点金属体が溶融すると、弾性片の弾性反発力で低融点金属体を破断させて弾性片を離隔させる構造、スプリングの一端をスプリングの引張り反力に抗して低融点金属体で固着し、低融点金属体が溶融すると、スプリングの引張り反力で低融点金属体を破断させて、スプリングを固着点から離隔させる構造等が周知されている。
しかしながら、これらの強制的作動構造では、弾性片やスプリングを収容する空間を必要とし、かかる空間が無い平型温度ヒュ−ズには適用し難い。
【０００６】
平型の強制的作動構造として、合成樹脂シ−トに切り込みを設け、この合成樹脂シ−トに低融点金属フィラメントを切り込みを縫って組み込んだものをヒュ−ズエレメントに使用し、作動温度のもとでの合成樹脂シ−トの熱膨張で低融点金属フィラメントに剪断力を作用させ、溶融した低融点金属フィラメントをその剪断力で破断させるものが公知であり（実公昭４９−２６４１７号公報）、この強制的作動構造を平型温度ヒュ−ズに適用することは可能である。
しかしながら、合成樹脂シ−トの熱膨張量は、合成樹脂の熱膨張係数が僅小であるために、破断箇所の拡開度がきわめて小さく、破断箇所でア−クが持続し易く、迅速な遮断作動を保証し難い。
【０００７】
本発明の目的は、正確かつ迅速な作動を保証できる合金型の平型温度ヒュ−ズを提供することにある。
【０００８】
【課題を解決するための手段】
本発明に係る一の平型温度ヒュ−ズは、絶縁基板に凹部が設けられ、ヒュ−ズエレメントとしての低融点金属体が絶縁基板上に前記凹部の間隙を保って配設され、該低融点金属体上に前記凹部を覆う圧縮状態の弾性体を介して外被体が被せられていることを特徴とする構成である。
本発明に係る他の平型温度ヒュ−ズは、絶縁基板に格子状または網状の絶縁スペ−サが設けられ、該絶縁スペ−サ上にヒュ−ズエレメントとしての低融点金属体が前記絶縁スペ−サの格子または網の目の間隙を保って配設され、前記低融点金属体上に圧縮状態の弾性体を介して外被体が被せられていることを特徴とする構成である。
本発明においては、これらの平型温度ヒュ−ズに対し、圧縮状態の弾性体に代え、低融点金属体の融点よりも低い温度で発泡する発泡性層を設けることも可能である。
【０００９】
【作用】
図１は本発明に係る平型温度ヒュ−ズの平常時の状態を示し、低融点金属体が未溶融であり、低融点金属体の降伏点強度が高いために、低融点金属体は弾性体で押圧されていても、変形されることなく安定に保持されている。
図２は本発明に係る平型温度ヒュ−ズの作動時の状態を示し、低融点金属体が溶融され弾性体の押圧力で変形されている。この場合、弾性体が凹部を埋めるように形状が回復し、凹部の上端エッジ箇所において、溶融低融点金属体が剪断変形されるために、溶融低融点金属体がこの箇所で確実に分断され圧縮弾性体が絶縁基板に溶融金属の介在なく直接に接触される。この無介在接触箇所においては、溶融金属（導電物）が存在せず、しかも、弾性体の圧縮応力のために接触圧力が作用する結果、高い沿面絶縁強度を呈し、通電が確実に遮断される。
これに対し、弾性体の直下に凹部が存在しない場合を仮想すると、溶融低融点金属体が弾性体の押圧力により圧縮変形されても、圧縮体直下の低融点金属体は分断されずに連続状態のままとなり易く、確実な通電遮断を保証し難い。
【００１０】
【実施例】
以下、図面を参照しつつ本発明の実施例について説明する。
図１の（イ）は本発明に係る平型温度ヒュ−ズの一実施例を一部を切開して示す平面図、図１の（ロ）は図１の（イ）におけるロ−ロ断面図である。
図１の（イ）及び図１の（ロ）において、１，１は一対のリ−ド導体であり、帯状導体が使用されている。２はリ−ド導体１，１間に接続された低融点金属体である。３は熱伝導性に優れた絶縁基板であり、セラミックス等の無機質板、硬質プラスチック板（例えば、ポリイミドシ−ト、ポリエステルシ−ト等）が使用される。４，４は絶縁基板３の片面に形成された凹部であり、絶縁基板３が両リ−ド導体１，１の端部及び低融点金属体２に跨って配設され、低融点金属体２と絶縁基板３の凹部底面４１との間に間隙が保たれている。５は上記凹部４，４を覆うように低融点金属体２上に配設された絶縁物の弾性体であり、例えば、シリコ−ンゴム発泡体が使用される。６は絶縁基板３の片面側に被せられた絶縁外被体であり、例えば、上記したセラミックス板等の無機質板、硬質プラスチック板等がその周囲において接着剤７、例えばエポキシ樹脂により上記絶縁基板３に接合されて上記の弾性体５が圧縮状態とされている。
上記絶縁基板３、外被体６が硬質プラスチック板の場合は、周囲部の接合は接着剤の外、熱融着により行うこともできる。
【００１１】
上記平型温度ヒュ−ズを製作するには、リ−ド導体１，１間に低融点金属体２を接続し、これらを絶縁基板３，絶縁外被体６で挾持すると共に絶縁基板６と低融点金属体２との間に弾性体５を介在させ、この弾性体５を圧縮しつつ両絶縁基板３，絶縁外被体６の周囲を接着剤７等で接合する方法を使用できる。また、上記弾性体の使用に代え、低融点金属体の融点よりも発泡温度が低い発泡性樹脂組成物を絶縁基板３，絶縁外被体６の周囲を接合するまえに、上側の絶縁外被体６の内面に塗布乾燥させておくか（発泡性樹脂組成物が液状の場合）または上側絶縁外被体６と低融点金属体２との間に介在させておき（発泡性樹脂組成物がフィルム状の場合）、次いで、絶縁基板３，絶縁外被体６の周囲を接着剤７等で接合し、而るのち、発泡性樹脂組成物を発泡させて圧縮状態とすることもできる。
また、上記発泡性樹脂組成物に、低融点金属体の融点よりもやや低い発泡温度のものを使用し、温度ヒュ−ズの機器への取り付け時には未発泡であるが、低融点金属体の溶融直前に発泡して低融点金属体への押圧力を発生させることもできる。
【００１２】
図２は本発明に係る平型温度ヒュ−ズの作動時の状態を示し、低融点金属体が溶融され、弾性体５または発泡性層が凹部４を埋めるように形状回復し、凹部４の上端エッジ箇所ｅにおいて、溶融低融点金属体が剪断変形され、溶融低融点金属体２０がこの箇所で確実に分断されて弾性体５等が絶縁基板３に溶融金属の介在なく直接に接触されている。この無介在接触箇所ｔにおいては、溶融金属（導電物）が存在せず、しかも、弾性体５等の押圧力のために接触圧力が作用する結果、高い沿面絶縁強度を呈し、通電が確実に遮断される。
【００１３】
上記において、低融点金属体２の線径に較べて凹部４の巾（低融点金属体２の長手方向に対する巾）が広過ぎたり、または凹部４の深さが浅過ぎると、平常時に既に低融点金属体２が凹部４の底部に接して凹部４内が弾性体５等でほぼ埋められてしまい、低融点金属体が溶融しても、弾性体等の形状の回復が僅かにとどめられて上記溶融低融点金属体の確実な剪断を促すことが困難になるので、凹部の巾を低融点金属体の直径の１〜３倍程度（１倍以下では、狭すぎて溶融低融点金属体の剪断が難しくなる）とし、凹部の深さを低融点金属体の直径の２〜４倍程度（４倍以上では絶縁基板の厚みを相当厚くする必要がある）とすることが好ましい。
上記凹部の個数は、できるだけ多くすることが好ましいが、上記の凹部の巾、低融点金属体の長さの範囲内での制約上、通常２〜３個とされる。
【００１４】
図３は本発明に係る平型温度ヒュ−ズの別実施例を示す説明図である。
図３において、３及び６は熱伝導性に優れた絶縁基板、例えば、セラミックス板、耐熱性プラスチックシ−トを、４０は絶縁基板３の直上に配される格子状または網状の絶縁スペ−サ（例えば、耐熱性プラスチック製）を、５は絶縁外被体６の直下に配される絶縁弾性シ−トを、２は絶縁弾性シ−ト５と格子状または網状の絶縁スペ−サ４０との間に配される蛇行状の低融点金属体を、１，１は蛇行状低融点金属体２の各端に接続されたリ−ド導体をそれぞれ示し、これらの部材が相互に重畳され両絶縁基板３，絶縁外被体６の周囲の接着剤による相互接合で絶縁弾性シ−ト５が圧縮応力状態にされて請求項２に係る平型温度ヒュ−ズに組立てられている。
【００１５】
この平型温度ヒュ−ズにおいても、格子状または網状の絶縁スペ−サ４０の格子または網の目の縦巾（低融点金属体の長手方向に対する巾）は低融点金属体２の直径の１〜３倍程度とし、格子または網の厚み（前記凹部の深さに相当）は、低融点金属体の直径の２〜４倍程度（４倍以上では絶縁スペ−サが厚くなり過ぎる）とすることが好ましい。
絶縁スペ−サ４０には、図４に示す横格子状のもの（ａは低融点金属体の長手方向を示している）の使用も可能である。
【００１６】
この平型温度ヒュ−ズに対しても、上記絶縁弾性シ−トの使用に代え、低融点金属体の融点よりも発泡温度が低い発泡性樹脂組成物を両絶縁基板の周囲を接合するまえに、上側の絶縁基板の内面に塗布乾燥させておくか（発泡性樹脂組成物が液状の場合）または上側絶縁基板と低融点金属体との間に介在させておき（発泡性樹脂組成物がフィルム状の場合）、次いで、両絶縁基板の周囲を接合し、而るのち、発泡性樹脂組成物を発泡させて圧縮状態とすることもできる。また、上記発泡性樹脂組成物に、低融点金属体の融点よりもやや低い発泡温度のものを使用し、温度ヒュ−ズの機器への取り付け時には未発泡であるが、低融点金属体の溶融直前に発泡して低融点金属体への押圧力を発生させることもできる。
【００１７】
本発明に係る平型温度ヒュ−ズにおいて、圧縮状態の弾性体に代え、低融点金属体の融点よりも低い温度で発泡する発泡性層を用い、低融点金属体の溶融直前に発泡性層が発泡して圧縮状態の弾性体になる場合、低融点金属体が溶融すると、上記と同様、弾性体が凹部を埋めるように形状回復し、凹部の上端エッジ箇所において、溶融低融点金属体が剪断変形され、溶融低融点金属体がこの箇所で確実に分断され圧縮弾性体が絶縁基板に溶融金属の介在なく直接に接触され、この無介在接触箇所の高い沿面絶縁強度のために、通電が確実に遮断される。この場合、平常時、発泡性層は、非圧縮状態であり、従って、平常時、低融点金属体は完全な無荷重状態であるので、クリ−プの畏れが皆無となり、発泡性層の発泡による低融点金属体への押圧力を大にしてそれだけ急駿な剪断を促すことが可能となる。
【００１８】
【発明の効果】
本発明に係る平型温度ヒュ−ズにおいては、低融点金属体直上と外被体内面間に介在させた弾性体または発泡性層を低融点金属体の溶融と同時に、低融点金属体直下の凹部を埋めるように形状を回復させ得るものであり、低融点金属体が溶融温度に加熱されてその低融点金属体の降伏点強度が大きく低下すれば、低融点金属体に酸化皮膜が在っても、その弾性体または発泡性層の形状回復で溶融低融点金属体を確実に分断でき、その分断箇所を弾性体または発泡性層の凹部面への加圧接触のために高絶縁強度とでき、通電を確実に遮断できる。その他、フラックスの使用を省略でき、製造が容易であるといった利点もある。
従って、本発明によれば、正確かつ迅速な作動を保証できる製造容易な合金型の平型温度ヒュ−ズを提供できる。
【図面の簡単な説明】
【図１】図１の（イ）は本発明に係る一の平型温度ヒュ−ズの一実施例を一部を切開して示す平面図、図１の（ロ）は図１の（イ）におけるロ−ロ断面図である。
【図２】図２は本発明に係る平型温度ヒュ−ズの作動時の状態を示す説明図である。
【図３】本発明に係る他の平型温度ヒュ−ズの一実施例を示す説明図である。
【図４】本発明に係る上記他の平型温度ヒュ−ズにおいて使用される絶縁スペ−サの別例を示す説明図である。
【符号の説明】
１リ−ド導体
２低融点金属体
３絶縁基板
４凹部
４０格子状または網状の絶縁スペ−サ
５弾性体または発泡性層
６絶縁外被体
７接着剤[0001]
[Industrial application fields]
The present invention relates to an alloy-type flat temperature fuse.
[0002]
[Prior art]
An alloy-type temperature fuse is well known as a temperature fuse for protecting electrical equipment, electronic equipment and the like from abnormal heat generation based on overcurrent in advance.
As is well known, in an alloy type temperature fuse, a low melting point metal body having a desired melting point is used as a fuse element in a coexistence state with a flux, and the low melting point metal body is generated by heat generated based on an overcurrent of a protected device. The melt of the low melting point metal body is removed by the active force of the already melted flux, and the surface tension in the presence of the melt flux promotes the spheroidization of the molten metal of the low melting point metal body. The molten metal is divided by the progress, and the arc generated by the split is eliminated by the increase of the distance between the breaks due to the progress of the subsequent spheronization, thereby cutting off the power supply to the equipment.
[0003]
Various types of alloy-type temperature fuses are used. A type in which a low-melting point metal body is disposed on an insulating substrate, and the insulating substrate is covered with the low-melting point metal body. Is advantageous for flattening and is frequently used as a flat temperature fuse.
[0004]
[Problems to be solved by the invention]
In the above alloy type temperature fuse, the flux is critically involved in the operation of the temperature fuse. Thus, the period until the temperature fuse actually operates, that is, the period during which the equipment continues to operate normally, is usually a long period of time, during which the temperature fuse is based on the load current of the equipment. Since it is exposed to a heat cycle and is subject to repeated fluctuations in thermal stress, depending on the material of the flux and the low-melting-point metal body, changes in the activity of the flux and the degree of surface oxidation of the low-melting-point metal body are caused.
[0005]
Conventionally, instead of operating the alloy type temperature fuse by the spheroidization division by the surface tension of the molten low melting point metal in the presence of the flux described above, a tensile force or shear force is applied to the low melting point metal body, It is known that when a low-melting-point metal body is melted, the low-melting-point metal body is forcibly broken by its tensile force or shearing force.
As a representative example of this forced operation structure, when the elastic pieces separated by a predetermined gap are forcibly brought into contact with each other to make the gap zero, the contact point is fixed with a low melting metal body, and the low melting metal body melts. The structure is such that the low melting point metal body is broken by the elastic repulsive force of the elastic piece to separate the elastic piece, and one end of the spring is fixed with the low melting point metal body against the tensile reaction force of the spring, and the low melting point metal body is melted Then, the structure etc. which fracture | rupture a low melting-point metal body with the tension reaction force of a spring and separate a spring from a sticking point are known.
However, these forced operation structures require a space for accommodating the elastic piece and the spring, and are difficult to apply to a flat temperature fuse without such a space.
[0006]
As a flat-type forced operation structure, a cut is made in a synthetic resin sheet, and a low melting point metal filament is cut into this synthetic resin sheet and incorporated into the fuse element. It is known that a shearing force is applied to a low melting point metal filament by thermal expansion of the original synthetic resin sheet, and the molten low melting point metal filament is broken by the shearing force (Japanese Utility Model Publication No. 49-26417). It is possible to apply this forced operating structure to a flat temperature fuse.
However, since the thermal expansion coefficient of the synthetic resin sheet is very small, the opening degree of the broken part is extremely small, and the arc is easily maintained at the broken part. It is difficult to guarantee the shut-off operation.
[0007]
An object of the present invention is to provide an alloy-type flat temperature fuse that can guarantee an accurate and rapid operation.
[0008]
[Means for Solving the Problems]
In one flat temperature fuse according to the present invention, a concave portion is provided on an insulating substrate, and a low melting point metal body as a fuse element is disposed on the insulating substrate with the gap of the concave portion being provided. An outer shell is covered on the melting point metal body through a compressed elastic body that covers the concave portion.
Other flat temperature fuse according to the present invention - figure lattice or mesh of insulating space in the insulating substrate - provided support, the insulating space - fuse on service - the low melting metal member as's elements the insulation The structure is characterized in that it is disposed while maintaining a space between lattices or meshes of a spacer, and a covering body is covered on the low melting point metal body through an elastic body in a compressed state.
In the present invention, it is also possible to provide a foamable layer that foams at a temperature lower than the melting point of the low melting point metal body instead of the elastic body in a compressed state with respect to these flat temperature fuses.
[0009]
[Action]
FIG. 1 shows a normal state of a flat temperature fuse according to the present invention. The low melting point metal body is unmelted, and the low melting point metal body has high yield point strength. Even if it is pressed by the body, it is stably held without being deformed.
FIG. 2 shows a state during operation of the flat temperature fuse according to the present invention, in which the low melting point metal body is melted and deformed by the pressing force of the elastic body. In this case, the shape is recovered so that the elastic body fills the concave portion, and the molten low melting point metal body is sheared and deformed at the upper edge portion of the concave portion. The elastic body is in direct contact with the insulating substrate without any molten metal. In this non-intervening contact location, there is no molten metal (conductive material), and contact pressure acts due to the compressive stress of the elastic body, resulting in high creepage insulation strength and reliable conduction interruption. .
On the other hand, if it is assumed that there is no concave portion immediately below the elastic body, even if the molten low melting point metal body is compressed and deformed by the pressing force of the elastic body, the low melting point metal body immediately below the compression body is not divided and is continuously separated. It is easy to remain in a state, and it is difficult to guarantee a reliable power interruption.
[0010]
【Example】
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 (a) is a plan view showing an embodiment of a flat temperature fuse according to the present invention with a part cut away, and FIG. 1 (b) is a cross-sectional view of FIG. FIG.
In FIG. 1A and FIG. 1B, reference numerals 1 and 1 denote a pair of lead conductors, and strip-like conductors are used. Reference numeral 2 denotes a low melting point metal body connected between the lead conductors 1 and 1. Reference numeral 3 denotes an insulating substrate having excellent thermal conductivity, and an inorganic plate such as ceramics or a hard plastic plate (for example, polyimide sheet, polyester sheet, etc.) is used. Reference numerals 4 and 4 denote concave portions formed on one side of the insulating substrate 3, and the insulating substrate 3 is disposed across the end portions of both the lead conductors 1 and 1 and the low melting point metal body 2. And a recess bottom surface 41 of the insulating substrate 3 is maintained. Reference numeral 5 denotes an insulating elastic body disposed on the low melting point metal body 2 so as to cover the concave portions 4 and 4, and, for example, a silicone rubber foam is used. Reference numeral 6 denotes an insulating covering member placed on one side of the insulating substrate 3. For example, an inorganic plate such as a ceramic plate, a hard plastic plate, or the like is surrounded by an adhesive 7 such as an epoxy resin around the insulating substrate 3. And the elastic body 5 is in a compressed state.
In the case where the insulating substrate 3 and the covering body 6 are hard plastic plates, the peripheral portions can be joined by heat fusion outside the adhesive.
[0011]
In order to manufacture the above flat temperature fuse, the low melting point metal body 2 is connected between the lead conductors 1 and 1, and these are held by the insulating substrate 3 and the insulating jacket 6, and the insulating substrate 6 It is possible to use a method in which an elastic body 5 is interposed between the low melting point metal body 2 and the periphery of the both insulating substrates 3 and the insulating jacket body 6 is bonded with an adhesive 7 or the like while the elastic body 5 is compressed. Further, instead of using the elastic body, before bonding the foamable resin composition having a foaming temperature lower than the melting point of the low-melting-point metal body around the insulating substrate 3 and the insulating jacket 6, the upper insulating jacket is used. It is coated and dried on the inner surface of the body 6 (when the foamable resin composition is in liquid form) or is interposed between the upper insulating jacket body 6 and the low melting point metal body 2 (the foamable resin composition is In the case of a film), the periphery of the insulating substrate 3 and the insulating jacket 6 can be joined with an adhesive 7 or the like, and then the foamable resin composition can be foamed to be in a compressed state.
In addition, a foaming resin composition having a foaming temperature slightly lower than the melting point of the low-melting metal body is used for the foamable resin composition, and the foaming resin composition is unfoamed when attached to a device having a temperature fuse. It is also possible to generate a pressing force on the low melting point metal body by foaming immediately before.
[0012]
FIG. 2 shows a state of operation of the flat temperature fuse according to the present invention. The low melting point metal body is melted, and the elastic body 5 or the foamable layer recovers its shape so as to fill the recess 4. At the upper edge portion e, the molten low-melting point metal body is sheared and deformed, and the molten low-melting point metal body 20 is reliably divided at this portion, so that the elastic body 5 and the like are in direct contact with the insulating substrate 3 without any molten metal interposed. Yes. In this non-intervening contact point t, there is no molten metal (conductive material), and the contact pressure acts due to the pressing force of the elastic body 5 or the like, resulting in high creepage insulation strength and reliable energization. Blocked.
[0013]
In the above, if the width of the concave portion 4 (width with respect to the longitudinal direction of the low melting point metal body 2) is too wide or the depth of the concave portion 4 is too shallow compared to the wire diameter of the low melting point metal body 2, it is already low in normal times. Even when the melting point metal body 2 is in contact with the bottom of the recess 4 and the inside of the recess 4 is almost filled with the elastic body 5 or the like, even if the low melting point metal body melts, the recovery of the shape of the elastic body or the like is limited. Since it is difficult to promote reliable shearing of the molten low melting point metal body, the width of the recess is about 1 to 3 times the diameter of the low melting point metal body. It is preferable that the depth of the recess is about 2 to 4 times the diameter of the low melting point metal body (if the thickness is 4 times or more, it is necessary to make the insulating substrate considerably thick).
Although it is preferable to increase the number of the concave portions as much as possible, the number of the concave portions is usually 2 to 3 due to restrictions within the range of the width of the concave portion and the length of the low melting point metal body.
[0014]
FIG. 3 is an explanatory view showing another embodiment of the flat type temperature fuse according to the present invention.
In FIG. 3, reference numerals 3 and 6 denote insulating substrates having excellent thermal conductivity, for example, ceramic plates and heat-resistant plastic sheets, and reference numeral 40 denotes a grid-like or net-like insulating spacer disposed immediately above the insulating substrate 3. (For example, made of heat-resistant plastic), 5 is an insulating elastic sheet disposed directly under the insulating jacket 6, 2 is an insulating elastic sheet 5 and a grid-like or mesh-like insulating spacer 40. 1 and 1 are lead conductors connected to respective ends of the meandering low melting point metal body 2, and these members are superposed on each other. The insulating elastic sheet 5 is brought into a state of compressive stress by mutual bonding with an adhesive around the insulating substrate 3 and the insulating jacket 6, and is assembled into a flat temperature fuse according to claim 2.
[0015]
Also in this flat temperature fuse, the vertical width of the lattice or mesh of the lattice-like or mesh-like insulating spacer 40 (the width with respect to the longitudinal direction of the low-melting-point metal body) is 1 of the diameter of the low-melting-point metal body 2. The thickness of the lattice or net (corresponding to the depth of the concave portion) is about 2 to 4 times the diameter of the low-melting point metal body (the insulation spacer becomes too thick if it is 4 times or more). It is preferable.
As the insulating spacer 40, it is also possible to use a horizontal lattice-shaped member (a indicates the longitudinal direction of the low melting point metal body) shown in FIG.
[0016]
For this flat temperature fuse, instead of using the above insulating elastic sheet, a foaming resin composition having a foaming temperature lower than the melting point of the low melting point metal body is bonded to the periphery of both insulating substrates. In addition, it is applied to and dried on the inner surface of the upper insulating substrate (when the foamable resin composition is in a liquid state) or is interposed between the upper insulating substrate and the low melting point metal body (the foamable resin composition is In the case of a film), the periphery of both insulating substrates can then be joined, and then the foamable resin composition can be foamed into a compressed state. In addition, a foaming resin composition having a foaming temperature slightly lower than the melting point of the low-melting metal body is used for the foamable resin composition, and the foaming resin composition is unfoamed when attached to a device having a temperature fuse. It is also possible to generate a pressing force on the low melting point metal body by foaming immediately before.
[0017]
In the flat temperature fuse according to the present invention, a foamable layer that foams at a temperature lower than the melting point of the low-melting metal body is used in place of the elastic body in the compressed state, and the foamable layer immediately before melting the low-melting metal body When the low melting point metal body melts, the shape of the elastic body recovers so as to fill the recess, and the melted low melting point metal body is formed at the upper edge portion of the recess. Due to shear deformation, the molten low-melting-point metal body is reliably divided at this location, and the compression elastic body is directly contacted with the insulating substrate without the molten metal intervening. It is reliably shut off. In this case, the foamable layer is normally in an uncompressed state, and therefore the low-melting point metal body is in a completely unloaded state in the normal state. It is possible to increase the pressing force on the low-melting point metal body by accelerating shearing accordingly.
[0018]
【The invention's effect】
In the flat temperature fuse according to the present invention, the elastic body or foam layer interposed between the low melting point metal body and the inner surface of the outer casing is simultaneously melted with the low melting point metal body and immediately below the low melting point metal body. If the low melting point metal body is heated to the melting temperature and the yield point strength of the low melting point metal body is greatly reduced, an oxide film is present on the low melting point metal body. However, the molten low melting point metal body can be reliably divided by restoring the shape of the elastic body or the foamable layer, and the divided portion has a high insulation strength due to pressure contact with the concave surface of the elastic body or the foamable layer. It is possible to cut off the power supply reliably. In addition, there is an advantage that the use of the flux can be omitted and the manufacture is easy.
Therefore, according to the present invention, it is possible to provide an easy-to-manufacture alloy-type flat temperature fuse that can guarantee accurate and rapid operation.
[Brief description of the drawings]
FIG. 1 (a) is a plan view showing a flat temperature fuse according to an embodiment of the present invention with a part cut away, and FIG. 1 (b) is a plan view of FIG. FIG.
FIG. 2 is an explanatory view showing a state during operation of a flat temperature fuse according to the present invention.
FIG. 3 is an explanatory view showing an example of another flat type temperature fuse according to the present invention.
FIG. 4 is an explanatory view showing another example of the insulating spacer used in the other flat temperature fuse according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Lead conductor 2 Low melting-point metal body 3 Insulating substrate 4 Recess 40 Lattice-like or net-like insulating spacer 5 Elastic body or foaming layer 6 Insulating envelope 7 Adhesive

Claims

A recessed portion is provided in the insulating substrate, and a low-melting point metal body as a fuse element is disposed on the insulating substrate while maintaining a gap between the recessed portions, and the compressed elastic body covering the recessed portion on the low-melting point metal body A flat type temperature fuse, characterized in that the outer cover is covered with a through-hole.

A lattice-like or mesh-like insulating spacer is provided on the insulating substrate, and a low melting point metal body as a fuse element is formed on the insulating spacer while maintaining a gap between the lattices or the meshes of the insulating spacer. A flat temperature fuse, characterized in that an outer cover is placed on the low-melting-point metal body through an elastic body in a compressed state.

A concave portion is provided in the insulating substrate, and a low melting point metal body as a fuse element is disposed on the insulating substrate while maintaining a gap between the concave portions. The low melting point metal body is covered with the concave portion, and the low melting point metal body is provided. A flat type temperature fuse characterized in that an outer cover is covered through a foaming layer that foams at a temperature lower than the melting point of the metal body.

A lattice-like or mesh-like insulating spacer is provided on the insulating substrate, and a low melting point metal body as a fuse element is formed on the insulating spacer while maintaining a gap between the lattices or the meshes of the insulating spacer. And a covering body is covered on the low melting point metal body through a foamable layer that covers a lattice or a net of the insulating spacer and foams at a temperature lower than the melting point of the low melting point metal body. A flat type temperature fuse characterized by having