JP3439807B2 - Ceramic heating element - Google Patents
Ceramic heating elementInfo
- Publication number
- JP3439807B2 JP3439807B2 JP29178993A JP29178993A JP3439807B2 JP 3439807 B2 JP3439807 B2 JP 3439807B2 JP 29178993 A JP29178993 A JP 29178993A JP 29178993 A JP29178993 A JP 29178993A JP 3439807 B2 JP3439807 B2 JP 3439807B2
- Authority
- JP
- Japan
- Prior art keywords
- layer
- heating resistor
- resistor layer
- heating
- conductive material
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Description
【発明の詳細な説明】Detailed Description of the Invention
【０００１】[0001]
【産業上の利用分野】本発明は各種加熱用ヒーター等に
好適な高温用のセラミック発熱体に関し、とりわけディ
ーゼルエンジンの始動時やアイドリング時に副燃焼室内
を急速に予熱する自己飽和型のグロープラグに用いられ
るセラミック発熱体に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high temperature ceramic heating element suitable for various heating heaters, and more particularly to a self-saturation type glow plug which rapidly preheats a sub combustion chamber at the time of starting or idling a diesel engine. The present invention relates to a ceramic heating element used.
【０００２】[0002]
【従来の技術】従来よりディーゼルエンジンの始動促進
に用いられるグロープラグや各種点火用及び加熱用ヒー
ターとして、耐熱金属製のシース内に耐熱絶縁粉末を充
填し、該耐熱絶縁粉末中にニッケル（Ｎｉ）−クロム
（Ｃｒ）等を主体とする高融点金属線から成る発熱抵抗
体を埋設したシーズヒーターや、高電圧の火花放電を利
用する各種点火装置が使用されていた。2. Description of the Related Art Conventionally, as a glow plug and various heaters for ignition and heating used for accelerating the starting of a diesel engine, a heat resistant insulating powder is filled in a sheath made of a heat resistant metal, and nickel (Ni) is contained in the heat resistant insulating powder. ) -Chromium (Cr) or the like, a sheathed heater in which a heating resistor made of a high melting point metal wire is embedded, and various ignition devices utilizing high-voltage spark discharge have been used.
【０００３】しかしながら、前記シーズヒーターは、耐
熱金属製のシース内に充填された耐熱絶縁粉末を介して
発熱抵抗体の熱を伝えるため、短時間の急速昇温が困難
であり、その上、耐摩耗性や耐久性に劣るという問題が
ある他、前記火花放電を利用した各種点火装置も、点火
時に雑音等の電波障害を生じたり、確実な点火と未着火
の場合の安全性という点からの信頼性に欠ける等の欠点
があった。However, since the sheathed heater transfers the heat of the heat-generating resistor through the heat-resistant insulating powder filled in the sheath made of heat-resistant metal, it is difficult to rapidly raise the temperature in a short time. In addition to the problem of inferior wear and durability, various ignition devices using the spark discharge also cause radio interference such as noise at the time of ignition, or in terms of safety in the case of reliable ignition and non-ignition. There were drawbacks such as lack of reliability.
【０００４】そこで、熱伝達効率が優れ、短時間の急速
昇温が可能で、電波障害が発生せず、しかも確実に点火
して安全性を確保し、耐摩耗性と耐久性に優れた信頼性
の高い発熱体として、セラミック焼結体中に高融点金属
の線材から成る発熱抵抗体を埋設したセラミック発熱体
が、内燃機関のグロープラグをはじめ、各種加熱用ヒー
ターとして広く利用されるようになってきた。Therefore, heat transfer efficiency is excellent, rapid temperature rise is possible in a short time, radio wave interference does not occur, and reliable ignition is ensured to ensure safety, and abrasion resistance and durability are excellent. As a highly heating element, a ceramic heating element in which a heating resistor made of a wire of a high melting point metal is embedded in a ceramic sintered body is widely used as a heater for various heating such as a glow plug of an internal combustion engine. It's coming.
【０００５】しかしながら、前記セラミック発熱体で
は、発熱抵抗体を急速昇温した後、飽和温度で安定した
発熱特性を得ることが困難であった。However, in the ceramic heating element, it is difficult to obtain stable heating characteristics at the saturation temperature after the heating resistor is rapidly heated.
【０００６】そこで、図３に示すように高融点金属やそ
れらの化合物等を主体とする２種類の導電性セラミック
材を用いて発熱抵抗体１３、１４をセラミック基体１５
上に形成し、その上に別の基体を重ねて焼成一体化した
セラミック発熱体１６が提案されている（特開平４−２
６８１１２号公報参照）。Therefore, as shown in FIG. 3, the heating resistors 13 and 14 are made into a ceramic base 15 by using two kinds of conductive ceramic materials mainly composed of refractory metals and their compounds.
There is proposed a ceramic heating element 16 which is formed on the upper surface of the substrate, and another substrate is superposed on it and fired and integrated (JP-A 4-2).
68112).
【０００７】[0007]
【発明が解決しようとする課題】しかしながら、前記セ
ラミック発熱体１６は、導電性セラミック材で発熱抵抗
体１３、１４が形成されているため、一般に発熱抵抗体
の抵抗値が高く、ディーゼルエンジン用のグロープラグ
として用いた場合、使用電圧が１０〜３５Ｖと低いた
め、リード部１７と発熱抵抗体１４との抵抗比を充分に
設定するためには、発熱抵抗体１４の全抵抗を下げる必
要があり、その対策のひとつとして発熱抵抗体１４の膜
厚を厚くすることがあげられるが、膜厚が厚くなると焼
成時の熱膨張差により発熱抵抗体１４にクラックが発生
し易いため、膜厚に限界があり、その結果、リード部１
７が昇温して発熱抵抗体１４に抵抗変化や電極の取り出
し金具との接続不良を起こして耐久性に劣る恐れがある
他、全長が長くなって強度的にも問題を生じる恐れがあ
る等の課題があった。However, since the ceramic heating element 16 has the heating resistors 13 and 14 formed of an electrically conductive ceramic material, the resistance value of the heating resistor is generally high, and the heating value of the heating resistor for a diesel engine is high. When used as a glow plug, since the operating voltage is as low as 10 to 35 V, it is necessary to lower the total resistance of the heating resistor 14 in order to sufficiently set the resistance ratio between the lead portion 17 and the heating resistor 14. One of the countermeasures is to increase the film thickness of the heating resistor 14, but if the film thickness is increased, cracks are likely to occur in the heating resistor 14 due to the difference in thermal expansion during firing, so the film thickness is limited. As a result, the lead part 1
7 may rise in temperature to cause a resistance change in the heating resistor 14 or a connection failure with the electrode take-out fitting, resulting in inferior durability. In addition, the entire length may become long, which may cause a problem in strength. There was a problem.
【０００８】[0008]
【発明の目的】本発明は前記欠点に鑑み開発されたもの
で、その目的は、無機導電材から成る発熱抵抗体層とリ
ード線との接続部が昇温せず、該接続部で発熱抵抗体層
が抵抗変化を生じて断線したりせず、長時間の連続稼動
が可能で、耐久性に優れた簡単な構造のセラミック発熱
体を提供することにある。SUMMARY OF THE INVENTION The present invention has been developed in view of the above-mentioned drawbacks, and an object thereof is to prevent the temperature of a connecting portion between a heating resistor layer made of an inorganic conductive material and a lead wire from rising, and to prevent a heating resistance at the connecting portion. It is an object of the present invention to provide a ceramic heating element having a simple structure that is capable of continuous operation for a long time without causing a break in the body layer due to a change in resistance, and having excellent durability.
【０００９】[0009]
【課題を解決するための手段】本発明のセラミック発熱
体は、印刷方法等で形成した略平行な少なくとも２層の
無機導電材から成る第１の発熱抵抗体層と、該第１の各
発熱抵抗体層の端部に少なくとも一部を重ねて形成した
無機導電材から成る第２の発熱抵抗体層を介して接続し
た高融点金属の線材等から成るリード線と、同様の印刷
方法等で形成した無機導電材から成り前記リード線の他
端に接続する複数個に分割した電極取り出し層を、それ
ぞれ電気絶縁性セラミック焼結体中に埋設して一体化し
たことを特徴とするものであり、とりわけ、第２の発熱
抵抗体層の導通抵抗および電極取り出し層の導通抵抗
が、第１の発熱抵抗体層の導通抵抗よりも低く、第１の
発熱抵抗体層に一部重ねて形成した第２の発熱抵抗体層
の先端から、第２の発熱抵抗体層に接続したリード線の
先端までの距離が３ｍｍ以上１０ｍｍ以下であることが
望ましく、さらに、リード線に接続した無機導電材から
成る第２の発熱抵抗体層の幅が、少なくとも第２の発熱
抵抗体層を重ねた部分の第１の発熱抵抗体層の幅より小
さいことがより望ましいものである。The ceramic heating element of the present invention comprises a first heating resistor layer formed of at least two substantially parallel inorganic conductive materials formed by a printing method and the like, and each of the first heating elements. A lead wire made of a wire material of a refractory metal or the like connected through a second heating resistor layer made of an inorganic conductive material, which is formed by overlapping at least a part of the end of the resistor layer, and a similar printing method, etc. A plurality of divided electrode lead layers made of an inorganic conductive material and connected to the other end of the lead wire are embedded and integrated in an electrically insulating ceramic sintered body, respectively. In particular, the conduction resistance of the second heating resistor layer and the conduction resistance of the electrode lead-out layer are lower than the conduction resistance of the first heating resistor layer, and the second heating resistor layer is formed by partially overlapping the first heating resistor layer. From the tip of the second heating resistor layer to the second It is desirable that the distance to the tip of the lead wire connected to the thermal resistor layer is 3 mm or more and 10 mm or less, and further, the width of the second heating resistor layer made of an inorganic conductive material connected to the lead wire is at least It is more desirable that the width is smaller than the width of the first heating resistor layer in the portion where the two heating resistor layers are overlapped.
【００１０】[0010]
【作用】本発明のセラミック発熱体によれば、印刷方法
等で形成した略平行な少なくとも２層の無機導電材から
成る第１の発熱抵抗体層の端部に、少なくとも無機導電
材から成る第２の発熱抵抗体層の一部を重ねて形成し、
該第２の発熱抵抗体層を介して高融点金属の線材等から
成るリード線に接続することから、第１の発熱抵抗体層
が１０００〜１３００℃に及ぶ高温となっても、抵抗値
が低い第２の発熱抵抗体層は１０００℃以下にしか昇温
せず、リード線と接続する部分では抵抗変化を生じるよ
うな高温に曝される恐れがなく、急速昇温を損なうこと
なく好適な自己飽和温度特性が得られ、長時間の連続稼
動における耐久性及び信頼性が向上することになる。According to the ceramic heating element of the present invention, the first heating resistor layer formed of at least two substantially parallel inorganic conductive materials formed by a printing method or the like has at least one inorganic conductive material at the end thereof. Part of the heating resistor layer of 2 is formed by overlapping,
Since the first heating resistor layer is connected to a lead wire made of a wire material of a high melting point metal through the second heating resistor layer, the resistance value is high even when the temperature of the first heating resistor layer reaches 1000 to 1300 ° C. The second heating resistor layer, which has a low temperature, only heats up to 1000 ° C. or less, and there is no fear of being exposed to a high temperature that causes resistance change in the portion connected to the lead wire, which is suitable without impairing rapid temperature rising. Self-saturation temperature characteristics can be obtained, and durability and reliability in long-term continuous operation can be improved.
【００１１】[0011]
【実施例】以下、本発明のセラミック発熱体の一実施例
を図面に基づき説明する。図１は本発明のセラミック発
熱体の正面の要部を示す断面図であり、図２は本発明の
セラミック発熱体の側面の要部を示す断面図である。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the ceramic heating element of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing an essential part of a front surface of a ceramic heating element of the present invention, and FIG. 2 is a sectional view showing an essential part of a side surface of the ceramic heating element of the present invention.
【００１２】図１及び図２において、１は電気絶縁性セ
ラミック焼結体２中に、略平行な２層の無機導電材から
成る略Ｕ字状を成す第１の発熱抵抗体層３、４と、第１
の発熱抵抗体層３、４の各端部に少なくとも一部を重ね
て形成した第２の発熱抵抗体層５、６を介して接続した
高融点金属の線材から成るリード線７、８と、リード線
７、８にそれぞれ接続した無機導電材から成る複数個に
分割した電極取り出し層９、１０を埋設し、電極取り出
し層９、１０の一部が電気絶縁性セラミック焼結体２の
外周面に露出するとともに、その先端が略球面で、断面
が円形を成したセラミック発熱体である。In FIG. 1 and FIG. 2, reference numeral 1 denotes a first heating resistor layer 3, 4 having a substantially U-shape made of two substantially parallel inorganic conductive materials in an electrically insulating ceramic sintered body 2. And the first
Of the heating resistor layers 3 and 4, at least a part of which is overlapped with each other, and lead wires 7 and 8 made of a wire material of a high melting point metal connected through second heating resistor layers 5 and 6, respectively, A plurality of divided electrode lead-out layers 9 and 10 made of an inorganic conductive material, which are respectively connected to the lead wires 7 and 8, are buried, and part of the electrode lead-out layers 9 and 10 is the outer peripheral surface of the electrically insulating ceramic sintered body 2. It is a ceramic heating element which is exposed at the end of which is substantially spherical and has a circular cross section.
【００１３】前記リード線７、８と接続した無機導電材
から成る第２の発熱抵抗体層の幅１２は、少なくとも第
２の発熱抵抗体層５、６を重ねた部分の第１の発熱抵抗
体層の幅１１より小さい方が好ましく、第１の発熱抵抗
体層の幅１１の２５〜９０％程度が望ましい。The width 12 of the second heating resistor layer made of an inorganic conductive material, which is connected to the lead wires 7 and 8, is at least the first heating resistor in the portion where the second heating resistor layers 5 and 6 are overlapped. The width is preferably smaller than the width 11 of the body layer, and is preferably about 25 to 90% of the width 11 of the first heating resistor layer.
【００１４】尚、電気絶縁性セラミック焼結体２として
は、高温での耐酸化性や強度に優れた窒化珪素（Ｓｉ3
Ｎ4 ）を主成分とする焼結体が好適であるが、これに限
定されるものではない。。The electrically insulating ceramic sintered body 2 is made of silicon nitride (Si 3) which is excellent in oxidation resistance and strength at high temperatures.
A sintered body containing N 4 ) as a main component is suitable, but the sintered body is not limited thereto. .
【００１５】また、無機導電材から成る第１の発熱抵抗
体層３、４あるいは第２の発熱抵抗体層５、６、電極取
り出し層９、１０等の主成分は、タングステン（Ｗ）、
モリブデン（Ｍｏ）、レニウム（Ｒｅ）等の高融点金属
やその合金の他、例えばタングステンカーバイド（Ｗ
Ｃ）、窒化チタン（ＴｉＮ）や硼化ジルコニウム（Ｚｒ
Ｂ2 ）等の第４ａ族、第５ａ族、第６ａ族の炭化物また
は窒化物等があり、とりわけタングステンカーバイド
（ＷＣ）が好ましい。The first heating resistor layers 3 and 4 or the second heating resistor layers 5 and 6 and the electrode lead-out layers 9 and 10 made of an inorganic conductive material are mainly composed of tungsten (W),
In addition to refractory metals such as molybdenum (Mo) and rhenium (Re) and alloys thereof, for example, tungsten carbide (W
C), titanium nitride (TiN) and zirconium boride (Zr
There are carbides or nitrides of Group 4a, Group 5a, and Group 6a such as B 2 ), and tungsten carbide (WC) is particularly preferable.
【００１６】但し、第２の発熱抵抗体層５、６及び電極
取り出し層９、１０の無機導電材の導通抵抗は、第１の
発熱抵抗体層３、４より低抵抗であることが必要であ
る。However, the conduction resistance of the inorganic conductive material of the second heating resistor layers 5 and 6 and the electrode lead-out layers 9 and 10 must be lower than that of the first heating resistor layers 3 and 4. is there.
【００１７】更に、電気絶縁性セラミック焼結体２が、
窒化珪素（Ｓｉ3 Ｎ4 ）を主成分とする焼結体の場合に
は、第１の発熱抵抗体層３、４及び第２の発熱抵抗体層
５、６、電極取り出し層９、１０は、セラミック焼結体
２の主成分である窒化珪素（Ｓｉ3 Ｎ4 ）粉末にタング
ステンカーバイド（ＷＣ）を主成分として添加するか、
あるいは熱膨張係数を調整するために更に窒化硼素（Ｂ
Ｎ）粉末を添加し、それらの含有量を増減することで任
意の抵抗値に設定したものが好適である。Further, the electrically insulating ceramic sintered body 2 is
In the case of a sintered body containing silicon nitride (Si 3 N 4 ) as a main component, the first heating resistor layers 3 and 4, the second heating resistor layers 5 and 6, and the electrode lead-out layers 9 and 10 are , Adding tungsten carbide (WC) as a main component to silicon nitride (Si 3 N 4 ) powder which is the main component of the ceramic sintered body 2,
Alternatively, in order to adjust the coefficient of thermal expansion, boron nitride (B
It is preferable that N) powder is added and the content thereof is increased or decreased to set an arbitrary resistance value.
【００１８】要するに、高温まで無機導電材として電気
絶縁性セラミック焼結体との熱膨張差が小さく、熱衝撃
抵抗性に優れ、安定した特性を有するものであれば良
い。In short, any inorganic conductive material having a small difference in thermal expansion from the electrically insulating ceramic sintered body up to a high temperature, excellent thermal shock resistance, and stable characteristics may be used.
【００１９】前述のような第１の発熱抵抗体層３、４及
び第２の発熱抵抗体層５、６、電極取り出し層９、１０
としては、例えばタングステンカーバイド（ＷＣ）を６
５重量％以上含有したものを使用し、第１の発熱抵抗体
層３、４としてタングステンカーバイド（ＷＣ）が７０
〜９０重量％、第２の発熱抵抗体層５、６として同じく
８０〜９５重量％、電極取り出し層９、１０として同じ
く８５〜９５重量％とすると、望ましい抵抗比を設定す
ることができる。The first heating resistor layers 3 and 4 and the second heating resistor layers 5 and 6 and the electrode lead-out layers 9 and 10 as described above.
For example, tungsten carbide (WC) 6
A material containing 5 wt% or more of tungsten carbide (WC) 70 is used as the first heating resistor layers 3 and 4.
˜90% by weight, the second heating resistor layers 5, 6 are also 80-95% by weight, and the electrode extraction layers 9, 10 are 85-95% by weight, so that a desired resistance ratio can be set.
【００２０】一方、リード線７、８には、高融点金属で
あるタングステン（Ｗ）、モリブデン（Ｍｏ）、レニウ
ム（Ｒｅ）やその合金等が上げられるが、とりわけタン
グステン（Ｗ）が好適である。On the other hand, for the lead wires 7 and 8, high melting point metals such as tungsten (W), molybdenum (Mo), rhenium (Re) and alloys thereof can be used, but tungsten (W) is particularly preferable. .
【００２１】また、セラミック発熱体の先端を略球面と
し、その断面を円形と成したのは、先端部近傍に最高発
熱部を有し、外周に効果的に均一に発熱させるためであ
り、この形状に限定されるものではない。The reason why the ceramic heating element has a substantially spherical tip and a circular cross section is to have a maximum heat generating portion near the tip and to effectively and uniformly generate heat on the outer periphery. The shape is not limited.
【００２２】尚、第２の発熱抵抗体層の距離ｌ、即ち第
１の発熱抵抗体層に一部重ねて形成した第２の発熱抵抗
体層の先端から、該第２の発熱抵抗体層に接続したリー
ド線の先端までの距離は、接続したリード線先端の温度
が１０００℃以下となれば抵抗変化を生じ難いため、３
ｍｍ以上に設定することが望ましい。The distance 1 of the second heating resistor layer, that is, from the tip of the second heating resistor layer formed by partially overlapping the first heating resistor layer, to the second heating resistor layer The distance to the tip of the lead wire connected to is 3 because the resistance change is less likely to occur if the temperature of the tip of the connected lead wire is 1000 ° C or less.
It is desirable to set it to mm or more.
【００２３】次に、本発明のセラミック発熱体を評価す
るにあたり、先ず、高純度の窒化珪素（Ｓｉ3 Ｎ4 ）粉
末に、焼結助剤としてイットリア（Ｙ2 Ｏ3 ）や希土類
元素の酸化物を添加混合して調製した造粒体を使用し、
プレス成形法等、周知の成形法により平板状の窒化珪素
を主成分とするセラミック成形体を作製する。Next, in evaluating the ceramic heating element of the present invention, first, high-purity silicon nitride (Si 3 N 4 ) powder is oxidized with yttria (Y 2 O 3 ) or a rare earth element as a sintering aid. Using a granulated body prepared by adding and mixing
A flat plate-shaped ceramic molded body containing silicon nitride as a main component is manufactured by a known molding method such as a press molding method.
【００２４】次に、タングステンカーバイド（ＷＣ）の
微粉末８０重量％と窒化珪素（Ｓｉ3 Ｎ4 ）の微粉末２
０重量％の混合粉末に溶媒を加えて調製したペーストを
使用して、スクリーン印刷法等により設計抵抗値に基づ
いた寸法の略Ｕ字形状のパターンで、セラミック焼結体
の先端より５ｍｍ以内に位置するようにそれぞれ別のセ
ラミック成形体の表面に、厚さ約４０μm の第１の発熱
抵抗体層３及び４を形成する。Next, 80% by weight of fine powder of tungsten carbide (WC) and fine powder of silicon nitride (Si 3 N 4 ) 2
Using a paste prepared by adding a solvent to 0% by weight of mixed powder, the pattern is approximately U-shaped with a size based on the designed resistance value by screen printing or the like, and within 5 mm from the tip of the ceramic sintered body. First heating resistor layers 3 and 4 having a thickness of about 40 μm are formed on the surfaces of different ceramic molded bodies so as to be positioned.
【００２５】次に、８５重量％のタングステンカーバイ
ド（ＷＣ）と１５重量％の窒化珪素（Ｓｉ3 Ｎ4 ）の各
微粉末から成るペーストを使用して、前記第１の発熱抵
抗体層３及び４の端部に一部重なり、第２の発熱抵抗体
層の幅１２が重なった第１の発熱抵抗体層の幅１１より
小さくなるパターンで、前記同様にして厚さ約４０μm
の第２の発熱抵抗体層５及び６をそれぞれ形成する。Next, using a paste composed of 85 wt% tungsten carbide (WC) and 15 wt% silicon nitride (Si 3 N 4 ) fine powder, the first heating resistor layer 3 and 4 has a pattern in which the width 12 of the second heating resistor layer partially overlaps the end portion of 4 and is smaller than the width 11 of the first heating resistor layer, and the thickness is about 40 μm in the same manner as described above.
The second heating resistor layers 5 and 6 are formed respectively.
【００２６】一方、電極取り出し層９及び１０も、第２
の発熱抵抗体層と同一組成のペーストを使用して前記セ
ラミック成形体表面の他端に、前記同様にして幅０．７
ｍｍ、厚さ７０μm のパターンを４個、セラミック成形
体の側面まで平行に所定の配置でそれぞれ形成した。On the other hand, the electrode lead-out layers 9 and 10 also have the second
Using a paste having the same composition as that of the heating resistor layer, the width of 0.7
Four patterns each having a thickness of 70 mm and a thickness of 70 μm were formed in parallel to the side surface of the ceramic molded body in a predetermined arrangement.
【００２７】次に、第１の発熱抵抗体層３及び４、第２
の発熱抵抗体層５及び６、電極取り出し層９及び１０を
それぞれ印刷形成した各セラミック成形体の上に、直径
０．２５ｍｍのタングステン（Ｗ）線を第２の発熱抵抗
体層と各電極取り出し層にそれぞれ接続するように載置
して重ね、その上に発熱抵抗体層と電極取り出し層を印
刷形成していないセラミック成形体を重ねた後、炭素
（Ｃ）を含む還元性の雰囲気下、１７５０℃の温度で１
時間、加圧焼成した。Next, the first heating resistor layers 3 and 4 and the second
On the respective ceramic molded bodies on which the heating resistor layers 5 and 6 and the electrode lead-out layers 9 and 10 are printed, a tungsten (W) wire having a diameter of 0.25 mm is taken out from the second heating resistor layer and the electrodes. The layers are placed so as to be connected to the layers, respectively, and stacked on top of each other, and the heating element layer and the ceramic molded body on which the electrode lead-out layer is not formed by printing are stacked thereon, and then, in a reducing atmosphere containing carbon (C), 1 at a temperature of 1750 ° C
It was baked under pressure for a time.
【００２８】かくして得られたセラミック焼結体の周囲
を研磨し、第１の発熱抵抗体層側の先端を球面とすると
ともに断面円形に加工し、埋設した各電極取り出し層の
端面を円柱側面に露出させ、直径約３．５ｍｍのセラミ
ック発熱体を作製した。The periphery of the ceramic sintered body thus obtained was polished, the tip on the side of the first heating resistor layer was made spherical and processed to have a circular cross section, and the end face of each embedded electrode take-out layer was made into a cylindrical side face. Exposed, a ceramic heating element having a diameter of about 3.5 mm was produced.
【００２９】前記セラミック発熱体を用いて、少なくと
も電極取り出し層の露出部にメタライズ法やメッキ法等
によりニッケル（Ｎｉ）等の金属被膜を形成した後、セ
ラミック発熱体の側面に露出した一方の電極取り出し層
と接続するように筒状金具を外嵌めし、還元ガス雰囲気
中で銀ろうにて接合して負電極とし、他方の電極取り出
し層に、線材またはキャップ状の金具より成る電極取り
出し金具を前記同様に銀ろうにて接合して正電極として
接続し、正負の電極を導出した評価用のセラミック発熱
体を作製した。Using the ceramic heating element, a metal coating such as nickel (Ni) is formed on at least the exposed portion of the electrode lead-out layer by a metallizing method or a plating method, and then one electrode exposed on the side surface of the ceramic heating element. A tubular metal fitting is externally fitted so as to be connected to the extraction layer, joined with silver brazing in a reducing gas atmosphere to form a negative electrode, and the other electrode extraction layer is equipped with an electrode extraction metal fitting consisting of a wire rod or a cap-shaped metal fitting. A ceramic heating element for evaluation was produced in which positive and negative electrodes were derived by joining with silver brazing and connecting as positive electrodes in the same manner as described above.
【００３０】次いで、前記評価用のセラミック発熱体を
使用し、該セラミック発熱体が１４００℃の温度で飽和
する１０〜３５Ｖの直流電圧を５分間通電した後、通電
を停止して２分間圧搾空気を吹きつけ強制冷却する工程
を１サイクルとする高負荷耐久試験を行い、１０００サ
イクル毎に両電極間の抵抗値を測定し、試験開始前の両
電極間の抵抗値に対する変化率が１０％を越えると不良
と判断し、１０％を越えた時のサイクル数で耐久性を評
価した。Then, using the above-mentioned ceramic heating element for evaluation, a direct current voltage of 10 to 35 V at which the ceramic heating element saturates at a temperature of 1400 ° C. is applied for 5 minutes, then the energization is stopped and compressed air is applied for 2 minutes. A high load endurance test in which the process of blowing and forcibly cooling is performed as one cycle, the resistance value between both electrodes is measured every 1000 cycles, and the rate of change with respect to the resistance value between both electrodes before the test starts is 10%. When it exceeded 10%, it was judged as defective, and durability was evaluated by the number of cycles when it exceeded 10%.
【００３１】尚、リード線と接続した無機導電材から成
る第２の発熱抵抗体層の幅ｗと第２の発熱抵抗体層を重
ねた第１の発熱抵抗体層の幅Ｗは、Ｘ線透過写真より計
測するとともに、同一仕様の他の評価用セラミック発熱
体をリード線と第２の発熱抵抗体層との接続部、及び第
１の発熱抵抗体層に第２の発熱抵抗体層が重なっている
部分のそれぞれで切断して幅Ｗとｗの寸法を確認した。The width w of the second heating resistor layer made of an inorganic conductive material connected to the lead wire and the width W of the first heating resistor layer in which the second heating resistor layer is overlapped are X-rays. While measuring from a transmission photograph, another ceramic heating element for evaluation having the same specifications is connected to the lead wire and the second heating resistor layer, and the second heating resistor layer is formed on the first heating resistor layer. The dimensions of widths W and w were confirmed by cutting at each of the overlapping portions.
【００３２】また、第１の発熱抵抗体層に一部重ねて形
成した第２の発熱抵抗体層の先端から、該第２の発熱抵
抗体層に接続したリード線の先端までの距離をＸ線透過
写真より計測して第２の発熱抵抗体層の距離ｌとし、最
高発熱部の温度を１４００℃とした時のリード線の先端
部に相当するセラミック発熱体の表面の温度を放射温度
計にて非接触で測定した。以上の結果を表１に示す。The distance from the tip of the second heating resistor layer, which is partially overlapped with the first heating resistor layer, to the tip of the lead wire connected to the second heating resistor layer is X. The temperature of the surface of the ceramic heating element corresponding to the tip of the lead wire when the distance 1 of the second heating resistor layer was measured from the line transmission photograph and the temperature of the highest heating part was 1400 ° C. was measured by a radiation thermometer. It was measured in a non-contact manner. The above results are shown in Table 1.
【００３３】[0033]
【表１】 [Table 1]
【００３４】[0034]
【発明の効果】叙上の如く、本発明のセラミック発熱体
は、略平行な少なくとも２層の無機導電材から成る第１
の発熱抵抗体層の端部に、無機導電材から成る第２の発
熱抵抗体層を少なくともその一部を重ねて形成し、該第
２の発熱抵抗体層を介して高融点金属の線材等から成る
リード線に接続することから、第１の発熱抵抗体層が高
温となっても、第２の発熱抵抗体層リード線との接続部
は昇温せず、該接続部で発熱抵抗体層が抵抗変化を生じ
て断線したりせず、その結果、長時間の連続稼動が可能
で、複雑な構造を必要としない耐久性に優れたセラミッ
ク発熱体を得ることができる。As described above, the ceramic heating element of the present invention comprises the first inorganic conductive material having at least two substantially parallel layers.
A second heating resistor layer made of an inorganic conductive material is formed at the end of the heating resistor layer so that at least a part of the second heating resistor layer is formed, and a wire of a refractory metal or the like via the second heating resistor layer. Since the first heating resistor layer is heated to a high temperature, the connecting portion with the second heating resistor layer lead wire is not heated, and the heating resistor is connected at the connecting portion. The layer does not cause resistance change and disconnection, and as a result, a ceramic heating element having excellent durability that can be continuously operated for a long time and does not require a complicated structure can be obtained.
【図１】本発明のセラミック発熱体の正面の要部を示す
断面図である。FIG. 1 is a sectional view showing a main part of a front surface of a ceramic heating element of the present invention.
【図２】本発明のセラミック発熱体の側面の要部を示す
断面図である。FIG. 2 is a sectional view showing a main part of a side surface of a ceramic heating element of the present invention.
【図３】従来のセラミック発熱体の正面の要部を示す断
面図である。FIG. 3 is a cross-sectional view showing a main part of a front surface of a conventional ceramic heating element.
１ セラミック発熱体 ２ 電気絶縁性セラミック焼結体 ３、４ 第１の発熱抵抗体層 ５、６ 第２の発熱抵抗体層 ７、８ リード線 ９、１０ 電極取り出し層 １１ 第１の発熱抵抗体層の幅 １２ 第２の発熱抵抗体層の幅 1 Ceramic heating element 2 Electrically insulating ceramic sintered body 3, 4 First heating resistor layer 5, 6 Second heating resistor layer 7,8 lead wire 9, 10 Electrode take-out layer 11 Width of the first heating resistor layer 12 Width of second heating resistor layer
───────────────────────────────────────────────────── フロントページの続き (58)調査した分野(Int.Cl.7，ＤＢ名) H05B 3/14 H05B 3/10 H05B 3/48 H05B 3/18 F23Q 7/00 ─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. 7 , DB name) H05B 3/14 H05B 3/10 H05B 3/48 H05B 3/18 F23Q 7/00
Claims (2)
た、少なくとも２層の無機導電材から成る第１の発熱抵
抗体層と、前記第１の発熱抵抗体層の端部に少なくとも
一部を重ねて形成した無機導電材から成る第２の発熱抵
抗体層と、前記第２の発熱抵抗体層を介して前記第１の
発熱抵抗体層と接続した高融点金属から成るリード線
と、前記リード線の他端に接続した無機導電材から成る
電極取り出し層とからなり、かつ前記第２の発熱抵抗体
層の導通抵抗および前記電極取り出し層の導通抵抗が、
前記第１の発熱抵抗体層の導通抵抗よりも低く、前記第
１の発熱抵抗体層に一部重ねて形成した前記第２の発熱
抵抗体層の先端から、前記第２の発熱抵抗体層に接続し
たリード線の先端までの距離が３ｍｍ以上１０ｍｍ以下
であることを特徴とするセラミック発熱体。1. An embedded in an electrically insulating ceramic sintered body.
In addition, the first heat-generating resistor composed of at least two layers of inorganic conductive material.
An antibody layer and at least an end portion of the first heating resistor layer
A second heat-generating resistor made of an inorganic conductive material formed by overlapping a part thereof.
The first heat generating resistor layer is interposed between the antibody layer and the second heat generating resistor layer.
Lead wire made of refractory metal connected to the heating resistor layer
And an inorganic conductive material connected to the other end of the lead wire.
An electrode take-out layer, and the second heating resistor
The conduction resistance of the layer and the conduction resistance of the electrode extraction layer are
Lower than the conduction resistance of the first heating resistor layer,
The second heat generation partly formed on the first heat generation resistor layer
Connect from the tip of the resistor layer to the second heating resistor layer.
The distance to the tip of the lead wire is 3 mm or more and 10 mm or less
Ceramic heating element, characterized in that it.
た、少なくとも２層の無機導電材から成る第１の発熱抵
抗体層と、前記第１の発熱抵抗体層の端部に少なくとも
一部を重ねて形成した無機導電材から成る第２の発熱抵
抗体層と、前記第２の発熱抵抗体層を介して前記第１の
発熱抵抗体層と接続した高融点金属から成るリード線
と、前記リード線の他端に接続した無機導電材から成る
電極取り出し層とからなり、かつ前記第２の発熱抵抗体
層の導通抵抗および前記電極取り出し層の導通抵抗が、
前記第１の発熱抵抗体層の導通抵抗よりも低く、前記リ
ード線と接続した無機導電材から成る前記第２の発熱抵
抗体層の幅が、少なくとも前記第２の発熱抵抗体層を重
ねた前記第１の発熱抵抗体層の幅より小であることを特
徴とするセラミック発熱体。2. Embedded in an electrically insulating ceramic sintered body.
In addition, the first heat-generating resistor composed of at least two layers of inorganic conductive material.
An antibody layer and at least an end portion of the first heating resistor layer
A second heat-generating resistor made of an inorganic conductive material formed by overlapping a part thereof.
The first heat generating resistor layer is interposed between the antibody layer and the second heat generating resistor layer.
Lead wire made of refractory metal connected to the heating resistor layer
And an inorganic conductive material connected to the other end of the lead wire.
An electrode take-out layer, and the second heating resistor
The conduction resistance of the layer and the conduction resistance of the electrode extraction layer are
It said first heating resistor layer lower than the conduction resistance of the width of the second heating resistor layer made of an inorganic conductive material connected to the lead wire, overlapped at least the second heating resistor layer ceramic heating element, characterized in that it is smaller than the width of the first heating resistor layer.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29178993A JP3439807B2 (en) | 1993-11-22 | 1993-11-22 | Ceramic heating element |
| US08/305,085 US5750958A (en) | 1993-09-20 | 1994-09-13 | Ceramic glow plug |
| DE4433505A DE4433505C2 (en) | 1993-09-20 | 1994-09-20 | ceramic glow |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29178993A JP3439807B2 (en) | 1993-11-22 | 1993-11-22 | Ceramic heating element |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH07142153A JPH07142153A (en) | 1995-06-02 |
| JP3439807B2 true JP3439807B2 (en) | 2003-08-25 |
Family
ID=17773454
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP29178993A Expired - Fee Related JP3439807B2 (en) | 1993-09-20 | 1993-11-22 | Ceramic heating element |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3439807B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19956019C2 (en) * | 1998-11-24 | 2001-09-27 | Bosch Braking Systems Co | Glow plug with a ceramic heating device and method for producing this glow plug |
| DE19957886A1 (en) | 1998-12-07 | 2000-07-20 | Bosch Braking Systems Co | Displacement pump eg for power assisted vehicle steering systems |
-
1993
- 1993-11-22 JP JP29178993A patent/JP3439807B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH07142153A (en) | 1995-06-02 |
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