JP2009252415A

JP2009252415A - Thermosensitive pellet type thermal fuse

Info

Publication number: JP2009252415A
Application number: JP2008096387A
Authority: JP
Inventors: Tokihiro Yoshikawa; 時弘吉川
Original assignee: NEC Schott Components Corp
Current assignee: NEC Schott Components Corp
Priority date: 2008-04-02
Filing date: 2008-04-02
Publication date: 2009-10-29
Also published as: CN101552155A

Abstract

<P>PROBLEM TO BE SOLVED: To minimize fluctuation of operating temperatures by suppressing deterioration of a thermosensitive pellet on which pressing force of a compression spring member is applied constantly with interposition of a metal pressing plate. <P>SOLUTION: The thermosensitive pellet type thermal fuse applies the pressing force of the compression spring 6 constantly on the thermosensitive pellet 3 which fuses at a predetermined operation temperature with interposition of the metal pressing plate 4. The thermosensitive pellet 3 is formed of thermoplastic resin material, and the metal pressing plate 4 is formed by using stainless material. The fluctuation with temporal changes of a predetermined operation temperature is suppressed by preventing discoloration, deterioration, and deformation of a contact surface on which both of the thermosenstive pellet 3 and the metal pressing plate 4 abut. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

この発明は金属ケ−スの筒型外囲器内に感温ペレット、圧縮ばねおよび可動接点体を収容して所定温度で回路を遮断または導通する感温ペレット型温度ヒュ−ズ、特に感温ペレットおよびこれに当接する金属押板に用いる材料選定により保管または正常使用中の環境条件に対しても安定して高精度の動作温度を維持するようにした感温ペレット型温度ヒュ−ズに関する。 The present invention relates to a temperature-sensitive pellet type temperature fuse that houses a temperature-sensitive pellet, a compression spring, and a movable contact body in a metal case cylindrical envelope and interrupts or conducts a circuit at a predetermined temperature. The present invention relates to a temperature-sensitive pellet type temperature fuse that can stably maintain a high-accuracy operating temperature even under environmental conditions during storage or normal use by selecting materials used for the pellet and the metal pressing plate that abuts the pellet.

温度ヒュ−ズは、機器の異常過熱を正確に検知し、速やかに回路を遮断または導通させる保護部品として、各種家電製品、携帯機器、通信機器、事務機器、車載機器、ＡＣアダプタ、充電器、モ−タ、電池、その他電子部品に使用されている。従来の温度ヒュ−ズは可溶体である感温材料により大きく２つに分類され、導電性の低融点合金を使用する可溶合金型温度ヒュ−ズと、非導電性の感温物質を使用する感温ペレット型温度ヒュ−ズがある。いずれも周囲温度の異常上昇時に作動して機器の電流遮断あるいは通電路の導通状態を形成して機器類を保護する、いわゆる非復帰型温度スイッチである。作動する温度は使用する感温材で決められるが、通常、６０℃から２５０℃、定格電流が０．５Ａから１５Ａの範囲で機能する保護部品として品揃えされている。 The temperature fuse accurately detects abnormal overheating of the equipment, and as a protective part that quickly shuts off or conducts the circuit, various home appliances, portable equipment, communication equipment, office equipment, in-vehicle equipment, AC adapter, charger, Used in motors, batteries, and other electronic components. Conventional temperature fuses are broadly classified into two types depending on the temperature-sensitive material that is a fusible material, using a soluble alloy-type temperature fuse that uses a conductive low-melting-point alloy and a non-conductive temperature-sensitive material. There is a temperature sensitive pellet type temperature fuse. All of these are so-called non-returnable temperature switches that are activated when the ambient temperature rises abnormally and protect the devices by forming a current interruption of the device or a conduction state of the energization path. The operating temperature is determined by the temperature-sensitive material to be used, but it is usually stocked as protective parts that function in a range of 60 to 250 ° C. and a rated current in the range of 0.5 to 15 A.

非導電性の感温ペレットを用いる感温ペレット型温度ヒュ−ズは、通常、筒型外囲器の両端にリ−ドを取付け、外囲器内に所定の温度で軟化溶融する物質をペレット形状に成形した感温ペレットを収容し、これに圧縮ばねなどで可動接点体に押圧力を作用させて構成されている。筒型外囲器に筒型金属ケ−スを用い、一方の端部でリ−ドをかしめ固定し、他方の開口にリ−ドを貫通配置した絶縁ブッシングを挿入固定し、この金属ケ−ス内に感温ペレット、強弱２種類の圧縮ばね、可動接点体および強圧縮ばねの押圧力を受けて感温ペレットと可動接点体に伝達付与する２枚の金属押板を組み込んで構成している（特許文献１、特許文献２、特許文献３、特許文献４参照）。
実開昭６２−５８８４３号公報特開平０５−１３５６４９号公報特開平１１−１１１１３５号公報特開２００３−３１７５９０号公報 A temperature-sensitive pellet type temperature fuse using a non-conductive temperature-sensitive pellet is usually equipped with a lead at both ends of a cylindrical envelope, and a material that softens and melts at a predetermined temperature in the envelope. A temperature-sensitive pellet molded into a shape is accommodated, and a pressing force is applied to the movable contact body by a compression spring or the like. A cylindrical metal case is used for the cylindrical envelope, and a lead is caulked and fixed at one end, and an insulating bushing is inserted and fixed to the other opening. It is constructed by incorporating two metal pressing plates that receive the pressure of the temperature-sensitive pellet, two types of compression springs, a movable contact body, and a strong compression spring, and transmit them to the temperature-sensitive pellet and the movable contact body. (See Patent Document 1, Patent Document 2, Patent Document 3, and Patent Document 4).
Japanese Utility Model Publication No. 62-58843 JP 05-135649 A JP-A-11-111135 JP 2003-317590 A

上述の感温ペレット型温度ヒュ−ズは、感温材に高純度の化学薬品や動作温度に応じて選択された熱可塑性樹脂を使用するもの、あるいは、押板を非変質材から選択することが知られている。これは、比較的純粋な化学薬品を使用してペレット成形し、高温高湿の環境条件下に置いた場合、感温ペレットと直接接触する銅材金属押板の変色を確認したことによる。化学薬品を材料とする感温ペレットが比較的活性化の強い銅と化学反応して、キレ−ト環を形成するキレ−ト効果等により銅による変色が発生する。また、銀を主体とする可動接点体と強圧縮ばねに押されて接触する側の金属押板では、常時押圧力が付与される接触面に銀マイグレ−ション現象により銅材金属押板にも変形や変質が惹起されてしまうことがある。寿命試験等によれば、銅材円板からなる金属押板を感温ペレットに押圧状態で放置した場合、温度６５℃、相対湿度９５％の高温高湿環境下で数百時間経過後、感温ペレットと接触する金属押板の当接面に明らかな変色が確認された。それゆえ、使用または保管状態の環境や経時的変化の影響を回避すると共に、高温高湿や有害ガスを浴びる周囲の厳しい雰囲気に曝される環境下においても感温ペレット自体に不具合を生じさせない感温ペレット型温度ヒュ−ズの提案が望まれていた。従来、金属押板材の銅または銅亜鉛と、感温ペレットの化学薬品との組合せで使用され、その結果、銅または銅亜鉛の押板の感温ペレットとの接触による変質劣化反応が確認された。こうした変質劣化反応を解消するため、金属押板および感温ペレットの材料選定の組合せや厳しい環境負荷下での選定法に着目しての改良提案が図られた。結果的に、温度ヒュ−ズの実用的寿命を延ばすことができるなど製品の差別化には極めて有利となる。また、別の課題として、従来、円板材質の銅との反応により融点や強度が変わりその結果として温度ヒュ−ズとして不適とされてきた化学薬品が多数あった。銅材金属押板の変質は感温ペレットに対してもその軟化、変形、昇華、潮解性などに影響を与えることが判明し、その改良方法が提案された。 The temperature-sensitive pellet type temperature fuse described above uses a high-purity chemical or a thermoplastic resin selected according to the operating temperature as the temperature-sensitive material, or selects the pressing plate from an unmodified material. It has been known. This is because when a pellet was formed using a relatively pure chemical and placed under high-temperature and high-humidity environmental conditions, the discoloration of the copper metal stamping plate in direct contact with the temperature-sensitive pellet was confirmed. The temperature-sensitive pellets made of chemicals chemically react with copper, which is relatively active, and discoloration due to copper occurs due to the chelate effect that forms a chelate ring. In addition, with the metal contact plate that is pressed and contacted by the strong contact spring and the movable contact body mainly composed of silver, the contact surface to which a constant pressing force is applied is also applied to the copper metal press plate due to the silver migration phenomenon. Deformation and alteration may occur. According to a life test and the like, when a metal pressing plate made of a copper material disk is left pressed on a temperature-sensitive pellet, the feeling after a few hundred hours has passed in a high-temperature and high-humidity environment at a temperature of 65 ° C. and a relative humidity of 95%. A clear discoloration was confirmed on the abutting surface of the metal pressing plate in contact with the warm pellet. Therefore, while avoiding the influence of the environment of use or storage and changes over time, the temperature-sensitive pellets themselves do not cause problems even in environments exposed to harsh surroundings exposed to high temperatures and high humidity and harmful gases. It has been desired to propose a hot pellet type temperature fuse. Conventionally, it has been used in combination with copper or copper zinc of metal stamping plate material and chemicals of temperature-sensitive pellets, and as a result, alteration deterioration reaction due to contact with temperature-sensitive pellets of copper or copper-zinc stamping plate was confirmed. . In order to eliminate such alteration deterioration reaction, improvement proposals were made focusing on the combination of material selection for metal press plates and temperature-sensitive pellets and the selection method under severe environmental loads. As a result, it is extremely advantageous for product differentiation, such as extending the practical life of the temperature fuse. As another problem, conventionally, there have been many chemicals that have been made unsuitable as a temperature fuse as a result of a change in melting point and strength due to reaction with copper as a disk material. It has been found that the alteration of the copper metal stamping plate affects the softening, deformation, sublimation, deliquescence, etc. of the temperature-sensitive pellets, and an improved method has been proposed.

したがって、本発明の目的は、上述する金属押板と対向する感温ペレットに生ずる変色・変質・変形の欠点を解消するため、感温ペレットに用いる感温材の選定とこれに当接する金属押板の化学的特性に着目して提案されたもので、感温ペレットの使用材料および常時押圧状態で接触する金属押板の材質に関し、一方または両者を所定の環境条件に耐える非変質材から選定する新規かつ改良された感温ペレット型温度ヒュ−ズを提供することにある。 Accordingly, an object of the present invention is to select the temperature-sensitive material used for the temperature-sensitive pellet and to contact the metal pressure plate in contact with the temperature-sensitive pellet in order to eliminate the disadvantages of discoloration, alteration, and deformation that occur in the temperature-sensitive pellet facing the above-described metal pressing plate. Proposed focusing on the chemical properties of the plate, with regard to the material used for the temperature-sensitive pellets and the material of the metal press plate that is always in contact, select one or both from non-modified materials that can withstand predetermined environmental conditions It is an object of the present invention to provide a new and improved thermosensitive pellet type temperature fuse.

また、圧縮ばね部材の押圧力が金属押板の介在で常時印加される感温ペレットの変質を抑止して、動作温度の変動をミニマム化する。ステンレス材の金属押板と特に熱可塑性樹脂材を感温材に用いた感温ペレットとの組合せにおいて、環境負荷を与えた際の評価結果から感温ペレットを選定して使用した感温型温度ヒュ−ズの提供を目的とする。 Further, the change of the operating temperature is minimized by suppressing the alteration of the temperature-sensitive pellets to which the pressing force of the compression spring member is constantly applied through the metal pressing plate. The temperature-sensitive mold temperature selected from the evaluation results when environmental impact is applied to the combination of a metal stamping plate made of stainless steel and a temperature-sensitive pellet using a thermoplastic resin material as the temperature-sensitive material. The purpose is to provide fuses.

本発明によれば、所定の動作温度で軟化溶融する感温ペレットを可動接点体、金属押板および圧縮ばね部材と共に収容した金属ケ−スと、この金属ケ−スに関し一端でかしめ固定したリ−ドおよび他端で開口閉塞用絶縁ブッシングを貫通し内方先端に固定接点を有するリ−ドを含む一対の導出リ−ド部材とを具備し、前記感温ペレットの動作時に前記圧縮ばね部材のばね圧作用で前記可動接点体を金属ケ−ス内壁面に沿って接触摺動させて前記固定接点から離隔して一対の導出リ−ド部材間を遮断させる感温ペレット型温度ヒュ−ズにおいて、前記可動接点体と前記感温ペレットとの間に強圧縮ばね部材が配置され、少なくとも前記強圧縮ばね部材と前記感温ペレットとの間にばね押圧力を伝達する金属押板を介在させ、前記感温ペレットは前記金属押板の接触により経時的変化による変質を回避する感温材から選定され、それにより前記感温ペレットの変色・変質・変形を抑止することを特徴とする感温ペレット型温度ヒュ−ズが提供される。たとえば、金属押板用非変質材には、ステンレスの化学的に安定な金属材料であって所定の機械的強度を有するものが選定され、感温ペレットの感温材には使用される金属押板の材料との組合せに関し、相互の接触当接面に変色・変質・変形の回避可能物質を選定する。熱可塑性樹脂材感温ペレットとステンレス材金属押板の組合せで使用することが好ましく、その作用効果は機械的強度の向上のみならず変質劣化の抑制効果が顕著に認められる。ステンレス製押板は強度および変質抑止効果で従来の銅材に比較して有利であることが判明している。これはステンレスが腐食やさび防止の目的で使用するのは勿論のことであるが、温度ヒュ−ズにおける熱可塑性樹脂材の感温ペレットと金属押板との適応で注目に値する。 According to the present invention, a metal case in which a temperature-sensitive pellet that is softened and melted at a predetermined operating temperature is accommodated together with a movable contact body, a metal pressing plate, and a compression spring member, and a rib that is caulked and fixed at one end with respect to the metal case. A pair of lead-out lead members including a lead and a lead passing through an insulating bushing for closing the opening at the other end and having a fixed contact at the inner tip, and the compression spring member during operation of the temperature-sensitive pellet A temperature-sensitive pellet type temperature fuse in which the movable contact body is contacted and slid along the inner wall surface of the metal case by the spring pressure action to separate the fixed lead member from the pair of lead-out lead members. A strong compression spring member is disposed between the movable contact body and the temperature-sensitive pellet, and a metal pressing plate for transmitting a spring pressing force is interposed between at least the strong compression spring member and the temperature-sensitive pellet. The temperature sensitive pellet is A temperature-sensitive pellet type temperature fuse selected from temperature-sensitive materials that avoid deterioration due to changes over time due to contact with the metal stamping plate, thereby inhibiting discoloration, quality change, and deformation of the temperature-sensitive pellets Is provided. For example, as the non-modified material for the metal pressing plate, a chemically stable metal material of stainless steel having a predetermined mechanical strength is selected, and the metal pressing material used for the temperature sensitive material of the temperature sensitive pellet is used. Regarding the combination with the material of the board, select a substance that can avoid discoloration, alteration, and deformation on the contact surface of each other. It is preferable to use a combination of a thermoplastic resin temperature-sensitive pellet and a stainless steel metal pressing plate, and the effect is not only an improvement in mechanical strength but also a remarkable effect of suppressing deterioration. Stainless steel push plates have been found to be advantageous over conventional copper materials in strength and alteration inhibiting effects. This is not to say that stainless steel is used for the purpose of preventing corrosion and rust, but is notable for the application of a temperature-sensitive pellet of a thermoplastic resin material and a metal pressing plate in a temperature fuse.

本発明の別の観点において、温度ヒュ−ズ用感温ペレットは、高温保管および／または高湿保管の与えられた環境負荷の耐久試験で金属押板との当接面で変質を生じない感熱材から選定することを特徴とする。その具体的条件としては、環境負荷の高温保管条件が所定の動作温度に対して凡そ１０℃低くして、５０００時間の経過後の変化を見て選定することでありる。また、環境負荷の高湿保管条件は、所定の動作温度が１００℃以下では温度６５℃、相対湿度９５％、１００℃を越えるものについては温度８５℃、相対湿度９５％の条件下で５０００時間の経過後の変化を見て選定することを特徴とするものである。ここで、このような耐久試験の選定基準は、５０００時間経過後の動作温度の変動が５℃以内であることを特徴とする感温ペレット型温度ヒュ−ズである。 In another aspect of the present invention, the temperature-sensitive pellet for temperature fuse is a heat-sensitive material that does not change in quality at the contact surface with the metal pressing plate in an endurance test for a given environmental load in high-temperature storage and / or high-humidity storage. It is selected from materials. The specific condition is that the high temperature storage condition of the environmental load is lowered by about 10 ° C. with respect to a predetermined operating temperature, and is selected by looking at the change after 5000 hours. In addition, the environmental load of the high humidity storage condition is that the temperature is 65 ° C. and the relative humidity is 95% when the predetermined operating temperature is 100 ° C. or less, and the temperature is 85 ° C. and the relative humidity is 95% for those exceeding 100 ° C. for 5000 hours. It is characterized in that it is selected by looking at the change after the lapse of time. Here, the selection criteria for such an endurance test is a temperature-sensitive pellet type temperature fuse characterized in that the fluctuation of the operating temperature after the lapse of 5000 hours is within 5 ° C.

この発明によれば、感温ペレットとこれと当接接触する金属押板との組合せ材料の選定により動作温度の精度が向上できることが見出された。たとえば、非変質材のステンレス押板と熱可塑性樹脂感温材の感温ペレットにより両者接触により生ずる感温ペレットの変色・変質・変形が回避される。また、感温ペレットとこれに当接する金属押板が高温高湿や有害ガスの厳しい外部環境に曝されることで生ずる感温ペレット自体の変質や不具合を抑止して動作温度の負荷環境による変動をミニマム化する。特に、従来の銅材の金属押板の使用時に認められた変色・変質による悪影響と感温ペレットの変質により生ずる軟化溶融点や動作温度の変動等の不具合発生が解消される。本発明の温度ヒュ−ズは、その保管並びに使用中の環境負荷に対する経時変化において、高温や高湿度の雰囲気中に置かれても長期にわたり安定化が図られる。したがって、金属押板の材質に伴う感温ペレットとの化学的反応による腐食や特性の変化を阻止する。特に、温度ヒュ−ズの電気的特性を含めた性能低下を防止し、経年変化に対しても所定の動作温度で正確に作動するなど安定性と信頼性の確保に役立つ。本発明の効果を示す一例として、特定試験による評価法において、金属押板が従来の銅または銅亜鉛か、本発明のステンレスかの違いで作用効果上の有意差を検証した。この特定試験法は動作温度に関する熱劣化加速試験であり、所定の負荷環境（１００℃／３０分⇔−３０℃／３０分：１０００回）後に一定荷重を加えた際の熱変形温度、すなわち、動作温度を測定する評価方法である。この方法で動作温度１１３℃のポリオレフィン系樹脂である低密度ポリエチレンを感温材に用いた感温ペレットは、初期品と環境負荷後の動作温度の差を計測した結果では、従来の銅製金属押板を使用した場合での差が５℃以上離れていたのに対し、ステンレス製金属押板を使用した場合での差は０．５℃であった。したがって、本発明は高温・高湿保管等の環境負荷を付与した後、動作温度の変動をミニマム化して動作上で高精度を維持し、信頼性を高めることを明らかにした。なお、この熱劣化加速試験では試料の温度を一定のプログラムによって変化させながら荷重を加えてその物質の変形を温度または時間の関数として測定する熱機械分析（ＴＭＡ）手法を採用した。試験に使用した測定器は島津製作所製ＴＭＡ−５０が使用され、測定条件は昇温速度１℃／分、圧縮荷重値１０ｇｆでどちらも同じ条件で計測している。また、銅材との接触による融点変化や強度変化のため温度ヒュ−ズ用の感温ペレットとして不適とされた化学薬品もステンレス材を使用することで使用できるようになるなど化学薬品の選択肢を広くすることができるなどの効果がある。 According to the present invention, it has been found that the accuracy of the operating temperature can be improved by selecting a combination material of the temperature-sensitive pellet and the metal pressing plate in contact with the temperature-sensitive pellet. For example, discoloration / degeneration / deformation of the temperature-sensitive pellets caused by contact between the non-modified material stainless steel pressing plate and the thermoplastic resin temperature-sensitive material is avoided. In addition, the temperature-sensitive pellets and the metal press plate that abuts them are exposed to the harsh external environment of high temperature, high humidity, and harmful gases to prevent alteration and malfunction of the temperature-sensitive pellets themselves. To the minimum. In particular, problems such as adverse effects due to discoloration and alteration recognized when using a conventional metal stamping plate made of copper material and fluctuations in softening melting point and operating temperature caused by alteration of temperature-sensitive pellets are eliminated. The temperature fuse of the present invention can be stabilized over a long period of time even when it is placed in an atmosphere of high temperature or high humidity in the course of storage and environmental changes during use. Therefore, the corrosion and the characteristic change by the chemical reaction with the temperature sensitive pellet accompanying the material of the metal pressing plate are prevented. In particular, it is useful for ensuring stability and reliability, such as preventing performance deterioration including the electrical characteristics of the temperature fuse, and accurately operating at a predetermined operating temperature against aging. As an example showing the effect of the present invention, in the evaluation method based on a specific test, a significant difference in operational effect was verified depending on whether the metal pressing plate was conventional copper or copper zinc or stainless steel of the present invention. This specific test method is a thermal degradation acceleration test related to the operating temperature, and the heat distortion temperature when a constant load is applied after a predetermined load environment (100 ° C./30 minutes⇔−30 ° C./30 minutes: 1000 times), that is, This is an evaluation method for measuring the operating temperature. With this method, the temperature-sensitive pellets using low-density polyethylene, which is a polyolefin resin with an operating temperature of 113 ° C, as the temperature-sensitive material are measured by measuring the difference in operating temperature after the initial product and environmental load. The difference when using a plate was 5 ° C. or more, whereas the difference when using a stainless steel metal pressing plate was 0.5 ° C. Therefore, it has been clarified that the present invention minimizes the fluctuation of the operating temperature after applying an environmental load such as high temperature / humidity storage to maintain high accuracy in operation and increase reliability. In this thermal degradation acceleration test, a thermomechanical analysis (TMA) method was adopted in which a load was applied while changing the temperature of the sample according to a certain program and the deformation of the material was measured as a function of temperature or time. TMA-50 manufactured by Shimadzu Corporation is used as the measuring instrument used for the test, and the measurement conditions are a temperature increase rate of 1 ° C./min and a compression load value of 10 gf, both of which are measured under the same conditions. In addition, chemicals that have been made unsuitable as temperature-sensitive pellets for temperature fuses due to changes in melting point and strength due to contact with copper materials can be used by using stainless steel. There are effects such as widening.

本発明によれば、所定の動作温度で溶融する感温ペレットと、この感温ペレットを収容する筒型金属ケ−スと、この金属ケ−スの一端でかしめ固定した第１リ−ド部材と、この金属ケ−スの他端開口を閉塞する絶縁ブッシングと、この絶縁ブッシングを貫通し内方端面に固定接点を形成する第２リ−ド部材と、この金属ケ−スに収容して内壁面と接触する可動接点体と、この可動接点体に係留する圧縮ばね部材と、この圧縮ばね部材の押圧力を伝達する金属押板とを具備し、前記金属押板および前記感温ペレットは、相互の接触当接部位に経時的変化を伴わない非変質材が選定され、それにより前記第１および第２リ−ド部材間の電気回路を遮断する所定動作温度の設定値に関し、経過時間的に変動する値をミニマム化することを特徴とする感温ペレット型温度ヒュ−ズが開示される。ここで、前記感温ペレットは熱可塑性樹脂材であり、前記金属押板は所定の機械的強度を有するステンレス材であり、それにより前記感温ペレットと前記金属押板との接触により生ずる経時的変化を抑止することを特徴とする。さらに、この感温ペレットは、高温保管および／または高湿保管の与えられた環境負荷の耐久試験で前記金属押板との当接面で変質を生じない感熱材から選定することを特徴とする感温ペレット型温度ヒュ−ズを開示する。 According to the present invention, a temperature-sensitive pellet that melts at a predetermined operating temperature, a cylindrical metal case that houses the temperature-sensitive pellet, and a first lead member that is caulked and fixed at one end of the metal case. An insulating bushing that closes the other end opening of the metal case, a second lead member that penetrates the insulating bushing and forms a fixed contact on the inner end surface thereof, and is accommodated in the metal case. A movable contact body that contacts the inner wall surface, a compression spring member moored to the movable contact body, and a metal pressing plate that transmits the pressing force of the compression spring member, the metal pressing plate and the temperature-sensitive pellet are The non-deteriorating material that does not change with time in the mutual contact contact part is selected, and thereby the set time of the predetermined operating temperature for cutting off the electric circuit between the first and second lead members, the elapsed time Characterized by minimizing the fluctuating value A thermosensitive pellet type thermal fuse -'s is disclosed. Here, the temperature-sensitive pellet is a thermoplastic resin material, and the metal pressing plate is a stainless material having a predetermined mechanical strength, so that the temperature-sensitive pellet is brought into contact with the metal pressing plate over time. It is characterized by deterring changes. Further, the temperature-sensitive pellet is selected from heat-sensitive materials that do not change in quality at the contact surface with the metal pressing plate in an endurance test for a given environmental load in high-temperature storage and / or high-humidity storage. A temperature sensitive pellet type temperature fuse is disclosed.

本発明の感温ペレット型温度ヒュ−ズは、図１に示されるように、所定の動作温度で軟化溶融する感温ペレットを可動接点体、金属押板および強弱圧縮ばね部材と共に収容した金属ケ−スと、この金属ケ−スに関し一端でかしめ固定したリ−ドおよび他端で開口閉塞用絶縁ブッシングを貫通し内方先端に固定接点を有するリ−ドを含む一対の導出リ−ド部材とを具備し、感温ペレットの動作時に前記圧縮ばね部材のばね圧作用で可動接点体を金属ケ−ス内壁面に沿って接触摺動させて固定接点から離隔して一対の導出リ−ド部材間を遮断させる感温ペレット型温度ヒュ−ズである。ここで、前記感温ペレットは熱可塑性樹脂材のオレフィン系樹脂が使用され、前記金属押板は所定の機械的強度を有するステンレス材からなることを特徴とする。換言すると、所定の温度で軟化溶融する感温ペレット３と、この感温ペレットを収容する筒型金属ケ−ス１と、この金属ケ−スの一端でかしめ固定する第１リ−ド部材２と、この金属ケ−スの他端で開口を閉塞する絶縁ブッシング９と、この絶縁ブッシングを貫通し内方端面に固定接点を形成する第２リ−ド部材１０と、この金属ケ−スに収容して内壁面と接触する可動接点体７と、この可動接点体に係留する強圧縮ばね６および弱圧縮ばね８の圧縮ばね部材と、この圧縮ばね部材の押圧をほぼ均一に伝達するため前記強圧縮ばね６の両側に配置した金属押板４，５とを具備し、前記金属押板の少なくとも前記感温ペレット３と接触する金属押板４はステンレス材を用い、それにより前記感温ペレットの変質を抑止し所定の動作温度の環境負荷による変動をミニマム化して動作温度の精度を高めたことを特徴とする感温ペレット型温度ヒュ−ズである。具体的には、所定の動作温度で溶融する感温ペレット３に常時圧縮ばね６の押圧力を金属押板４の介在により印加する感温ペレット型温度ヒュ−ズにおいて、感温ペレット３は熱可塑性樹脂材、および金属押板４はステンレス材を使用し、両者が当接する接触面の変色・変質・変形を回避して所定の動作温度の経時的変化に伴う変動を抑止する。それ故に、圧縮ばね部材の押圧力が金属押板の介在で常時印加される感温ペレットの変質を抑止して、動作温度の変動をミニマム化することができる。なお、圧縮ばね部材は強圧縮ばねと弱圧縮ばねを含み、強圧縮ばねの両側に金属押板が組み込まれる。強圧縮ばねが一方で弱圧縮ばねの弾性力に抗して可動接点体を固定接点に押圧接触させると共に他方で感温ペレットに押圧力を付与しており、いずれも金属押板の介在により組立の容易化と共にばね押圧力付与の安定化が図られる。 As shown in FIG. 1, the temperature-sensitive pellet type temperature fuse of the present invention comprises a metal case that contains a temperature-sensitive pellet that softens and melts at a predetermined operating temperature together with a movable contact body, a metal pressing plate, and a strong and weak compression spring member. A pair of lead members including a lead that is caulked and fixed at one end with respect to the metal case, and a lead that passes through an insulating bushing for closing the opening at the other end and has a fixed contact at the inner end. And a pair of lead leads separated from the fixed contact by sliding the movable contact body along the inner wall surface of the metal case by the spring pressure action of the compression spring member during the operation of the temperature sensitive pellet. This is a temperature-sensitive pellet type temperature fuse for blocking between members. Here, the temperature-sensitive pellet is made of an olefin resin, which is a thermoplastic resin material, and the metal pressing plate is made of a stainless material having a predetermined mechanical strength. In other words, a temperature-sensitive pellet 3 that softens and melts at a predetermined temperature, a cylindrical metal case 1 that accommodates the temperature-sensitive pellet, and a first lead member 2 that is caulked and fixed at one end of the metal case. An insulating bushing 9 that closes the opening at the other end of the metal case, a second lead member 10 that penetrates the insulating bushing and forms a fixed contact on the inner end surface, and the metal case. The movable contact body 7 which is accommodated and contacts the inner wall surface, the compression spring members of the strong compression spring 6 and the weak compression spring 8 moored to the movable contact body, and the pressing force of the compression spring member are transmitted substantially uniformly. Metal pressing plates 4 and 5 disposed on both sides of the strong compression spring 6 are used, and the metal pressing plate 4 that contacts at least the temperature sensitive pellet 3 of the metal pressing plate is made of stainless steel, whereby the temperature sensitive pellet. To prevent environmental degradation at the specified operating temperature Sensitive, characterized in that enhanced precision of minimization to operating temperature variations due to thermal pellet type thermal fuse - a's. Specifically, in the temperature-sensitive pellet type temperature fuse in which the pressing force of the compression spring 6 is constantly applied to the temperature-sensitive pellet 3 that melts at a predetermined operating temperature through the metal pressing plate 4, the temperature-sensitive pellet 3 is heated. The plastic resin material and the metal pressing plate 4 are made of stainless steel, and prevent changes in the predetermined operating temperature over time by avoiding discoloration, alteration, and deformation of the contact surface where both contact. Therefore, the change in the operating temperature can be minimized by suppressing the alteration of the temperature-sensitive pellets to which the pressing force of the compression spring member is constantly applied through the metal pressing plate. The compression spring member includes a strong compression spring and a weak compression spring, and metal pressing plates are incorporated on both sides of the strong compression spring. The strong compression spring, on the other hand, presses the movable contact body against the fixed contact against the elastic force of the weak compression spring and, on the other hand, applies pressing force to the temperature-sensitive pellets, both of which are assembled by means of a metal pressing plate. As a result, it is possible to stabilize the application of the spring pressing force.

図１および図２は本発明に係る実施例の感温ペレット型温度ヒュ−ズでそれぞれ常温の平常時と異常加熱した動作時の温度ヒュ−ズの部分断面図を示す。この感温ペレット型温度ヒュ−ズは、銅、黄銅などの良導体で熱伝導性良好な有底円筒状金属ケ−ス１と、その一方の有底側にかしめ固定した第１リ−ド部材２と、この金属ケ−ス１内に収容された感温ペレット３、一対の金属押板４、５、強圧縮ばね６、可動接点体７および弱圧縮ばね８を含むスイッチング機能部品と、金属ケ−ス１の開口に挿入された絶縁ブッシング９と、この絶縁ブッシング９を貫通して金属ケ−ス１から絶縁配置された第２リ−ド部材１０とを具備して構成される。ここで、１１は第２リ−ド部材１０の内方先端であり可動接点体７と接触する固定接点である。スイッチング機能部品の内、感温ペレット３は、熱可塑性樹脂を主材料として円柱状に成形加工されており、温度ヒュ−ズの所定の動作温度で溶融するが経時的に変質を生じないオレフィン系樹脂から選択したものである。金属押板４、５は本発明の特徴とする非変質材のステンレスで円板状押板からなり、強圧縮ばね６の両側に配置して感温ペレット３や可動接点体７への押圧力を平均的に作用するようにして均一にばね圧力を印加するように介在させている。また、可動接点体７は、導電性を考慮しなければならないので銀合金からなる良導体からなり、周辺に複数個の舌片を有する略星型で金属ケ−ス１の内壁面に適度の弾性をもって接触摺動させている。一方、金属ケ−ス１の開口を閉塞する絶縁ブッシング９は、その台形部分が金属ケ−ス１の先端側に形成した段部に係合され、金属ケ−ス１のはみ出た部分を内側に屈曲して金属ケ−ス１内での動きが止められる。加えて、絶縁ブッシング９の上面外方には流動状の封口樹脂１２で封止され、金属ケ−ス１と第２リ−ド部材１０との沿面距離を増大するためにセラミック絶縁筒体１３を固定する。 FIG. 1 and FIG. 2 are partial sectional views of temperature fuses during normal temperature operation and abnormal heating in the temperature-sensitive pellet type temperature fuse of the embodiment according to the present invention. The temperature-sensitive pellet type temperature fuse includes a bottomed cylindrical metal case 1 having a good conductor such as copper and brass and a good thermal conductivity, and a first lead member fixed by caulking to one bottomed side thereof. 2, a switching functional component including a temperature sensitive pellet 3 accommodated in the metal case 1, a pair of metal pressing plates 4, 5, a strong compression spring 6, a movable contact body 7 and a weak compression spring 8, and a metal An insulating bushing 9 inserted into the opening of the case 1 and a second lead member 10 that penetrates the insulating bushing 9 and is insulated from the metal case 1 are configured. Here, 11 is an inner tip of the second lead member 10 and is a fixed contact that contacts the movable contact body 7. Among the switching functional parts, the temperature-sensitive pellet 3 is formed into a cylindrical shape using thermoplastic resin as a main material, and melts at a predetermined operating temperature of the temperature fuse, but does not change in quality over time. It is selected from resins. The metal pressing plates 4 and 5 are made of a non-modified stainless steel disc-shaped pressing plate, which is a feature of the present invention, and are arranged on both sides of the strong compression spring 6 to press the pressure sensitive pellet 3 and the movable contact body 7. In such a manner that the spring pressure is uniformly applied so as to act on the average. The movable contact member 7 is made of a good conductor made of a silver alloy because of its conductivity, and is a substantially star shape having a plurality of tongue pieces in the periphery, and has an appropriate elasticity on the inner wall surface of the metal case 1. And sliding. On the other hand, the insulating bushing 9 that closes the opening of the metal case 1 has its trapezoidal portion engaged with a step formed on the tip side of the metal case 1, and the protruding portion of the metal case 1 is inside. And the movement in the metal case 1 is stopped. In addition, the outer surface of the insulating bushing 9 is sealed with a fluid sealing resin 12, and the ceramic insulating cylinder 13 is increased in order to increase the creeping distance between the metal case 1 and the second lead member 10. To fix.

上記構成において、常温時は感温ペレット３が固体であり、強圧縮ばね６は弱圧縮ばね８の弾性力に抗して可動接点体７を固定接点１１に強く押圧し接触状態にしている。従って、第１リ−ド部材２〜金属ケ−ス１〜可動接点体７〜固定接点１１〜第２リ−ド部材１０の経路で両リ−ド部材間は導通状態を保つ。一方、周囲温度が異常上昇して感温ペレット３の融点に達すると感温ペレット３が溶融し、その結果、強圧縮ばね６が伸長してその弾性力が消失するので、弱圧縮ばね８が伸長し可動接点体７が固定接点１１から離反することとなり、図２に示すように、第１および第２リ−ド部材間は遮断状態になる。ここで、感温ペレット３と金属押板４とは互いに平面的接触状態から解き放される。ここで注目すべきことは、金属押板４にステンレスの非変質材を選んだので、従来の銅材円板の場合に生じていた変色・変質はほとんど認めない。加えて、感温ペレットも熱可塑性樹脂でオレフィン系樹脂を使用したので所定の動作温度で安定して機能する。本実施例では、金属押板にステンレス円板を用いたので経時的にも変色・変質・変形を認めなかった。 In the above configuration, the temperature-sensitive pellet 3 is solid at normal temperature, and the strong compression spring 6 strongly presses the movable contact body 7 against the fixed contact 11 against the elastic force of the weak compression spring 8 to bring it into contact. Therefore, the conductive state is maintained between the lead members in the path from the first lead member 2 to the metal case 1 to the movable contact body 7 to the fixed contact 11 to the second lead member 10. On the other hand, when the ambient temperature rises abnormally and reaches the melting point of the temperature-sensitive pellet 3, the temperature-sensitive pellet 3 melts. As a result, the strong compression spring 6 expands and its elastic force disappears. As a result, the movable contact body 7 is separated from the fixed contact 11, and the first and second lead members are cut off as shown in FIG. Here, the temperature sensitive pellet 3 and the metal pressing plate 4 are released from the planar contact state. What should be noted here is that the stainless steel non-altered material is selected for the metal pressing plate 4, and therefore, almost no discoloration or alteration has occurred in the case of a conventional copper disk. In addition, since the temperature-sensitive pellets are thermoplastic resins and olefin resins are used, they function stably at a predetermined operating temperature. In this example, since a stainless steel disk was used as the metal pressing plate, no discoloration, alteration, or deformation was observed over time.

このような温度ヒュ−ズの製造方法は、第１リ−ド部材２をかしめ固定した金属ケ−ス１を、第１リ−ド部材２を下側にして直立状に支持しておき、この金属ケ−ス１内に上端開口より感温ペレット３、金属押板４、強圧縮ばね６、金属押板５、可動接点体７、弱圧縮ばね８を順次挿入する。弱圧縮ばねの８挿入に続いて、予め絶縁ブッシング９に第２リ−ド部材９を挿通して一体化しておいた絶縁ブッシング９を金属ケ−ス１の開口部分に嵌合する。そして、金属ケ−ス１の絶縁ブッシング９よりもはみ出す部分を、中心軸側にかしめて絶縁ブッシング９を固定する。ついで、絶縁ブッシング９の上面に封口樹脂となる流動状樹脂１２を供給し、この樹脂が硬化しないうちに、第２リ−ド部材１０に絶縁筒体１３を挿通し、流動状樹脂に押し付ける。樹脂の硬化に先立ち、第２リ−ド部材１０と絶縁筒体１３の隙間を通じて流動樹脂１２が上昇し、絶縁筒体１３の上部に一部流出し、樹脂硬化の結果封口樹脂１２が残り、図１に示すような温度ヒュ−ズを得る。ここで感温ペレット３の選定について、環境負荷を付与した条件の下に選定することが提示される。具体的には高温保管および／または高湿保管の環境負荷を与えられた条件設定の下に、前記金属押板との当接面が少なくとも端面側部分で変質しない熱可塑性樹脂材から選定するものである。このうち環境負荷としての高温保管条件は所定の動作温度に対して凡そ１０℃低くして、５０００時間の経過後の変化を見て選定することが提案される。環境負荷の高湿保管条件は、所定の動作温度が１００℃以下では温度６５℃、相対湿度９５％、１００℃を越えるものについては温度８５℃、相対湿度９５％の条件下で５０００時間の経過後の変化を見て選定することが提案される。こうした条件化で選定された感温ペレットを使用することで所定の動作温度の変動値はミニマム化され、従来に比べて高精度で作動させることのできる感温ペレット型温度ヒュ−ズが提供できる。
In such a method for manufacturing a temperature fuse, the metal case 1 to which the first lead member 2 is caulked and fixed is supported upright with the first lead member 2 on the lower side, A temperature-sensitive pellet 3, a metal pressing plate 4, a strong compression spring 6, a metal pressing plate 5, a movable contact body 7, and a weak compression spring 8 are sequentially inserted into the metal case 1 from the upper end opening. Following the insertion of the weak compression spring 8, the insulating bushing 9, which is integrated by inserting the second lead member 9 into the insulating bushing 9 in advance, is fitted into the opening of the metal case 1. Then, the insulating bushing 9 is fixed by caulking the portion of the metal case 1 that protrudes beyond the insulating bushing 9 toward the central axis. Next, a fluid resin 12 serving as a sealing resin is supplied to the upper surface of the insulating bushing 9, and the insulating cylinder 13 is inserted into the second lead member 10 and pressed against the fluid resin before the resin is cured. Prior to the curing of the resin, the fluid resin 12 rises through the gap between the second lead member 10 and the insulating cylinder 13, partially flows out to the top of the insulating cylinder 13, and the sealing resin 12 remains as a result of the resin curing, A temperature fuse as shown in FIG. 1 is obtained. Here, the selection of the temperature-sensitive pellet 3 is proposed to be selected under conditions that give an environmental load. Specifically, selected from thermoplastic resin materials whose contact surface with the metal pressing plate does not change at least at the end surface side under the condition setting given environmental load of high temperature storage and / or high humidity storage It is. Among these, it is proposed that the high temperature storage condition as an environmental load is selected by looking at a change after a lapse of 5000 hours by lowering by about 10 ° C. with respect to a predetermined operating temperature. High humidity storage conditions for environmental load are as follows: when the predetermined operating temperature is 100 ° C. or lower, the temperature is 65 ° C. and the relative humidity is 95%. It is suggested to make a selection by looking at later changes. By using the temperature-sensitive pellets selected under these conditions, the fluctuation value of the predetermined operating temperature is minimized, and a temperature-sensitive pellet type temperature fuse that can be operated with higher accuracy than before can be provided. .

本発明の実施例で常温時（Ａ）の感温ペレット型温度ヒュ−ズの縦断面図The longitudinal cross-sectional view of the temperature-sensitive pellet type | mold temperature fuse at the time of normal temperature in the Example of this invention 本発明の実施例で、図１の異常温度上昇による動作後（Ｂ）の感温ペレット型温度ヒュ−ズの縦断面図1 is a longitudinal sectional view of a temperature-sensitive pellet type temperature fuse after operation due to an abnormal temperature rise in FIG.

符号の説明Explanation of symbols

１金属ケ−ス
２第１リ−ド部材（導出リ−ド部材）
３感温ペレット
４金属押板（ステンレス押板）
５金属押板
６強圧縮ばね
７可動接点体
８弱圧縮ばね
９絶縁ブッシング
１０第２リ−ド部材（導出リ−ド部材）
１１固定接点
１２封口樹脂
１３絶縁筒体
Ａ常温時の感温ペレット型温度ヒュ−ズ
Ｂ異常温度上昇による動作後の感温ペレット型温度ヒュ−ズ
1 Metal Case 2 First Lead Member (Lead Lead Member)
3 Temperature sensitive pellet 4 Metal press plate (stainless steel press plate)
5 Metal Press Plate 6 Strong Compression Spring 7 Movable Contact Body 8 Weak Compression Spring 9 Insulating Bushing 10 Second Lead Member (Lead Lead Member)
11 Fixed contact 12 Sealing resin 13 Insulating cylinder A Temperature sensitive pellet type temperature fuse B at normal temperature Temperature sensitive pellet type temperature fuse after operation due to abnormal temperature rise

Claims

所定の動作温度で軟化溶融する感温ペレットを可動接点体、金属押板および圧縮ばね部材と共に収容した金属ケ−スと、この金属ケ−スに関し一端でかしめ固定したリ−ドおよび他端で開口閉塞用絶縁ブッシングを貫通し内方先端に固定接点を有するリ−ドを含む一対の導出リ−ド部材とを具備し、前記感温ペレットの動作時に前記圧縮ばね部材のばね圧作用で前記可動接点体を金属ケ−ス内壁面に沿って接触摺動させて前記固定接点から離隔して一対の導出リ−ド部材間を遮断させる感温ペレット型温度ヒュ−ズにおいて、前記可動接点体と前記感温ペレットとの間に強圧縮ばね部材が配置され、少なくとも前記強圧縮ばね部材と前記感温ペレットとの間にばね押圧力を伝達する金属押板を介在させ、前記感温ペレットは前記金属押板の接触により経時的変化による変質を回避する感温材から選定され、それにより前記感温ペレットの変色・変質・変形を抑止することを特徴とする感温ペレット型温度ヒュ−ズ。 A metal case containing a temperature-sensitive pellet that softens and melts at a predetermined operating temperature together with a movable contact body, a metal pressing plate, and a compression spring member, and a lead that is caulked and fixed at one end with respect to the metal case and the other end. A pair of lead-out lead members including a lead having an insulating bushing for closing the opening and having a fixed contact at the inner tip, and the spring pressure action of the compression spring member during the operation of the temperature-sensitive pellet In the temperature-sensitive pellet type temperature fuse in which the movable contact body is contacted and slid along the inner wall surface of the metal case and separated from the fixed contact, the pair of lead-out lead members is cut off. A strong compression spring member is disposed between the temperature-sensitive pellet, and at least a metal pressing plate that transmits a spring pressing force is interposed between the strong compression spring member and the temperature-sensitive pellet. Contact of the metal pressing plate By being selected from the thermosensitive material to avoid deterioration due to changes over time, thereby thermosensitive pellet type thermal fuse, characterized in that to suppress the discoloration and deterioration or deformation of the thermosensitive pellet -'s.

所定の動作温度で溶融する感温ペレットと、この感温ペレットを収容する筒型金属ケ−スと、この金属ケ−スの一端でかしめ固定した第１リ−ド部材と、この金属ケ−スの他端開口を閉塞する絶縁ブッシングと、この絶縁ブッシングを貫通し内方端面に固定接点を形成する第２リ−ド部材と、この金属ケ−スに収容して内壁面と接触する可動接点体と、この可動接点体に係留する圧縮ばね部材と、この圧縮ばね部材の押圧力を伝達する金属押板とを具備し、前記金属押板および前記感温ペレットは、相互の接触当接部位に経時的変化を伴わない非変質材が選定され、それにより前記第１および第２リ−ド部材間の電気回路を遮断する所定動作温度の設定値に関し、経過時間的に変動する値をミニマム化することを特徴とする感温ペレット型温度ヒュ−ズ。 A temperature-sensitive pellet that melts at a predetermined operating temperature, a cylindrical metal case that accommodates the temperature-sensitive pellet, a first lead member that is caulked and fixed at one end of the metal case, and the metal case An insulating bushing that closes the other end opening of the sleeve, a second lead member that penetrates the insulating bushing and forms a fixed contact on the inner end surface, and a movable member that is accommodated in the metal case and contacts the inner wall surface A contact member, a compression spring member moored to the movable contact member, and a metal pressing plate that transmits a pressing force of the compression spring member. The metal pressing plate and the temperature-sensitive pellet are in contact with each other. A non-denatured material that does not change over time is selected for the part, and thereby a set value of a predetermined operating temperature that shuts off the electric circuit between the first and second lead members is a value that varies with time. Temperature-sensitive pellet mold temperature characterized by minimization Fuse -'s.

前記感温ペレットは熱可塑性樹脂材であり、前記金属押板は所定の機械的強度を有するステンレス材であり、それにより前記感温ペレットと前記金属押板との接触により生ずる経時的変化を抑止することを特徴とする請求項１または２に記載の感温ペレット型温度ヒュ−ズ。 The temperature-sensitive pellet is a thermoplastic resin material, and the metal pressing plate is a stainless material having a predetermined mechanical strength, thereby suppressing a change over time caused by contact between the temperature-sensitive pellet and the metal pressing plate. The temperature-sensitive pellet type temperature fuse according to claim 1 or 2.

前記感温ペレットは、高温保管および／または高湿保管の与えられた環境負荷の耐久試験で前記金属押板との当接面で変質を生じない感熱材から選定することを特徴とする請求項１または２に記載の感温ペレット型温度ヒュ−ズ。 The temperature-sensitive pellet is selected from heat-sensitive materials that do not change in quality at the contact surface with the metal pressing plate in an endurance test for a given environmental load in high-temperature storage and / or high-humidity storage. The temperature-sensitive pellet type temperature fuse according to 1 or 2.

前記環境負荷の高温保管条件は前記所定の動作温度に対して凡そ１０℃低くして、５０００時間の経過後の変化を見て選定することを特徴とする請求項４に記載の感温ペレット型温度ヒュ−ズ。 5. The temperature-sensitive pellet mold according to claim 4, wherein the high temperature storage condition of the environmental load is selected by looking at a change after a lapse of 5000 hours by lowering by about 10 ° C. with respect to the predetermined operating temperature. Temperature fuse.

前記環境負荷の高湿保管条件は、前記所定の動作温度が１００℃以下では温度６５℃、相対湿度９５％、１００℃を越えるものについては温度８５℃、相対湿度９５％の条件下で５０００時間の経過後の変化を見て選定することを特徴とする請求項４に記載の感温ペレット型温度ヒュ−ズ。 The high environmental humidity storage conditions are as follows: when the predetermined operating temperature is 100 ° C. or less, the temperature is 65 ° C. and the relative humidity is 95%, and for those exceeding 100 ° C., the temperature is 85 ° C. and the relative humidity is 95% for 5000 hours. 5. The temperature-sensitive pellet type temperature fuse according to claim 4, wherein the temperature-sensitive pellet type temperature fuse is selected in view of a change after elapse of time.

前記耐久試験の選定基準は、５０００時間経過後の動作温度の変動が５℃以内であることを特徴とする請求項５または６に記載の感温ペレット型温度ヒュ−ズ。
The temperature-sensitive pellet type temperature fuse according to claim 5 or 6, wherein the selection criterion for the durability test is that the fluctuation of the operating temperature after the lapse of 5000 hours is within 5 ° C.