JPS6161684B2 - - Google Patents
Info
- Publication number
- JPS6161684B2 JPS6161684B2 JP18835080A JP18835080A JPS6161684B2 JP S6161684 B2 JPS6161684 B2 JP S6161684B2 JP 18835080 A JP18835080 A JP 18835080A JP 18835080 A JP18835080 A JP 18835080A JP S6161684 B2 JPS6161684 B2 JP S6161684B2
- Authority
- JP
- Japan
- Prior art keywords
- temperature
- metal oxide
- constant
- thermistor element
- component
- 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
Links
- 239000000843 powder Substances 0.000 claims description 13
- 229910044991 metal oxide Inorganic materials 0.000 claims description 10
- 150000004706 metal oxides Chemical class 0.000 claims description 10
- 239000000203 mixture Substances 0.000 claims description 3
- 229910002076 stabilized zirconia Inorganic materials 0.000 claims description 3
- 230000005856 abnormality Effects 0.000 claims description 2
- WABPQHHGFIMREM-UHFFFAOYSA-N lead(0) Chemical compound [Pb] WABPQHHGFIMREM-UHFFFAOYSA-N 0.000 description 5
- 230000007423 decrease Effects 0.000 description 3
- 239000007789 gas Substances 0.000 description 3
- 238000005245 sintering Methods 0.000 description 3
- 241000501667 Etroplus Species 0.000 description 2
- 238000002485 combustion reaction Methods 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 238000010304 firing Methods 0.000 description 2
- 229910052746 lanthanum Inorganic materials 0.000 description 2
- FZLIPJUXYLNCLC-UHFFFAOYSA-N lanthanum atom Chemical compound [La] FZLIPJUXYLNCLC-UHFFFAOYSA-N 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 2
- 229910021193 La 2 O 3 Inorganic materials 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 238000009529 body temperature measurement Methods 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 230000003197 catalytic effect Effects 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000010416 ion conductor Substances 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 239000000615 nonconductor Substances 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 238000012805 post-processing Methods 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
Landscapes
- Measuring Temperature Or Quantity Of Heat (AREA)
- Thermistors And Varistors (AREA)
Description
本発明は高温用サーミスタ、詳しくは常温から
1200℃程度の高温まで使用することができるにも
かかわらず、断線の有無を容易に検知することの
できる高温用サーミスタに関するものである。
自動車の排気ガスを完全燃焼させるための触媒
マフラーあるいはサーマルリアクターの温度制御
等へ高温用サーミスタを使用することが従来より
考えられている。この場合作動温度を確実に検出
し、適温にて排気ガスの清浄化を効率よく行わせ
るため、内燃機関始動前において、サーミスタ素
子のリード線の断線を常温で検知可能にすること
が強く要望されていた。
しかし従来のサーミスタの抵抗−温度特性は、
一定の高温区域（400〜1200℃）では抵抗値が式
Ｒ＝RoeB（１／Ｔ−１／Ｔｏ）と指数関数的に減少する
が
常温時では抵抗値が非常に大きく電気絶縁体とな
るので、機関始動前における常温での断線の検知
は不可能とされていた。そこでこの対策として実
開昭50−124378号及び実公昭55−2573号では、サ
ーミスタ素子に補償抵抗体を並列に固着した高温
用サーミスタが提案されている。ところがこのよ
うな高温用サーミスタには次のような欠点があり
未だ実用的なものとは言えなかつた。
即ち
(1) サーミスタ素子と補償抵抗体との熱膨張率の
差により、サーミスタが高温に晒された場合
に、自動車の振動により補償抵抗体が脱落し易
い。
(2) 後加工によりサーミスタ素子に補償抵抗体を
固着する作業が困難である。
本発明者らは上記のような欠点を解消するため
鋭意検討の結果、上記(1)、(2)はサーミスタ素子と
補償抵抗体とを別体にして設ける限り必然的に生
じ、これを解決することには全く発想を変えなけ
ればならないと考え研究を重ねて本発明を完成し
た。
本発明の目的は上記欠点のない高温用サーミス
タを提供することにある。
即ちこの発明は大きい負の抵抗温度係数をもつ
第１の金属酸化物粉末（(a)成分）と、小さい抵抗
温度係数をもつ第２の金属酸化物粉末（(b)成分）
との混合物の焼結体であり、高温域では、第１の
金属酸化物のＢ定数に近いＢ定数を示し、低温側
では第２の金属酸化物のＢ定数に近いＢ定数を示
し、かつ20℃において500KΩ以下の抵抗値とし
て断線等の異常を検知しうるようにした高温用サ
ーミスタ素子を要旨とする。
以下に本発明を図面に記載した実施例と共に詳
細に説明する。図において１は焼結して得たサー
ミスタ素子であり、２はそれを貫通するリード線
である。１のサーミスタ素子は次の(a)(b)成分から
成る。
(a)成分の代表例としては酸素イオン伝導体であ
るZrO2にY2O3、CaO、MgO等を添加した安定化
ジルコニアを挙げることができ、(b)成分の代表例
としては次式で表される高温まで安定な電子伝導
性材料であるランタンクロマイド化合物を挙げる
ことができる。
（La1−xCax）CrO3
又は（La1−xSrx）CrO3
（ただしＯ≦ｘ≦0.2）
ｘを入れると安定構造となるが過大であると耐
久性が悪くなる。
上記(a)(b)成分の代表例から成る高温用サーミス
タを製造する１方法を述べれば次のようになる。
ZrO2粉末にY2O3粉末を混合し1300〜1400℃に
て２時間仮焼した後、ポツトミルにて湿式粉砕し
た粉末ａを調製する。またこれとは別にLa2O3又
はLa（OH）3粉末にCr2O3とCaCO3の粉末を混合
し、1300〜1400℃で２時間仮焼した後、ポツトミ
ルにて湿式粉砕して粉末ｂを調製する。次に粉末
ａとｂとを所定の割合で混合し、バインダーを加
え、更に白金の0.4mmφリード線２を埋め込みつ
つ第１図に示すデイスク形状に成形する。そして
これを1400〜1700℃にて１時間位焼成すれば良
い。焼成後のデイスク寸法は径3.0mmφ×厚み2.0
mmであり、リード線間隔は1.5mmであり、開口気
孔率約10％の焼結体とした。なお(a)成分の平均粒
径は10μ前後、(b)成分の平均粒径は１μ以下であ
ることが好ましい。
本発明者の実験によれば、上記方法に於て粉末
ａとｂとの重量比を次表のように変化させて抵抗
温度変化を測定したところ第３図のようであつ
た。なお図中Ｐ〜Ｕの記号は第１表に対応する。
The present invention is a high-temperature thermistor, specifically, a high-temperature thermistor.
The present invention relates to a high-temperature thermistor that can be used at temperatures as high as 1200°C and yet can easily detect the presence or absence of wire breakage. BACKGROUND ART Conventionally, it has been considered to use high-temperature thermistors for temperature control of catalytic mufflers or thermal reactors for complete combustion of automobile exhaust gas. In this case, in order to reliably detect the operating temperature and efficiently purify the exhaust gas at an appropriate temperature, it is strongly desired to be able to detect disconnection of the thermistor element lead wire at room temperature before starting the internal combustion engine. was. However, the resistance-temperature characteristics of conventional thermistors are
In a certain high temperature area (400 to 1200℃), the resistance value decreases exponentially according to the formula R = RoeB (1/T-1/To), but at room temperature, the resistance value is very large and it becomes an electrical insulator. It was believed that it was impossible to detect a disconnection at room temperature before the engine started. As a countermeasure to this problem, high-temperature thermistors have been proposed in Japanese Utility Model Application Publications No. 124378/1982 and Japanese Utility Model Publication No. 2573/1983, in which a compensation resistor is fixed in parallel to a thermistor element. However, such high-temperature thermistors have the following drawbacks and cannot be said to be of practical use yet. That is, (1) due to the difference in thermal expansion coefficient between the thermistor element and the compensating resistor, when the thermistor is exposed to high temperatures, the compensating resistor is likely to fall off due to vibrations of the automobile. (2) It is difficult to attach the compensation resistor to the thermistor element during post-processing. The inventors of the present invention have made extensive studies to eliminate the above-mentioned drawbacks, and have found that (1) and (2) above will inevitably occur as long as the thermistor element and the compensation resistor are provided separately. I thought that I needed to completely change my way of thinking in order to do this, and after repeated research I completed this invention. The object of the present invention is to provide a high temperature thermistor that does not have the above-mentioned drawbacks. That is, this invention uses a first metal oxide powder (component (a)) having a large negative temperature coefficient of resistance and a second metal oxide powder (component (b)) having a small temperature coefficient of resistance.
It is a sintered body of a mixture of, in the high temperature range, exhibits a B constant close to the B constant of the first metal oxide, and in the low temperature range exhibits a B constant close to the B constant of the second metal oxide, and The gist of this article is a high-temperature thermistor element that can detect abnormalities such as wire breakage with a resistance value of 500KΩ or less at 20℃. The present invention will be explained in detail below along with embodiments shown in the drawings. In the figure, 1 is a thermistor element obtained by sintering, and 2 is a lead wire passing through it. Thermistor element 1 consists of the following components (a) and (b). A typical example of component (a) is stabilized zirconia, which is made by adding Y 2 O 3 , CaO, MgO, etc. to ZrO 2 , which is an oxygen ion conductor, and a typical example of component (b) is the following formula: Lanthanum chromide compounds, which are electron-conductive materials that are stable up to high temperatures, can be mentioned. (La 1 −xCax)CrO 3 or (La 1 −xSrx)CrO 3 (O≦x≦0.2) If x is added, a stable structure can be obtained, but if it is too large, durability will deteriorate. One method for manufacturing a high-temperature thermistor made of typical examples of components (a) and (b) above will be described as follows. ZrO 2 powder is mixed with Y 2 O 3 powder, calcined at 1300 to 1400° C. for 2 hours, and then wet-pulverized in a pot mill to prepare powder a. Separately, La 2 O 3 or La(OH) 3 powder is mixed with Cr 2 O 3 and CaCO 3 powder, calcined at 1300 to 1400°C for 2 hours, and then wet-pulverized in a pot mill to form a powder. Prepare b. Next, powders a and b are mixed at a predetermined ratio, a binder is added, and a platinum lead wire 2 of 0.4 mm diameter is embedded in the powder to form the disc shape shown in FIG. Then, this may be fired at 1400 to 1700°C for about 1 hour. Disc dimensions after firing are diameter 3.0mmφ x thickness 2.0
mm, the lead wire spacing was 1.5 mm, and the sintered body had an open porosity of about 10%. The average particle size of component (a) is preferably around 10 μm, and the average particle size of component (b) is preferably 1 μm or less. According to experiments conducted by the present inventor, changes in resistance with temperature were measured by changing the weight ratio of powders a and b as shown in the following table in the above method, and the results were as shown in FIG. 3. Note that the symbols P to U in the figure correspond to Table 1.
【表】
第３図から明らかなように、(a)成分と(b)成分と
が共存すると700〜900℃以上の領域（高温域）で
は抵抗値が不変かもしくはそれ程低下せず、かつ
Ｂ定数も第１成分と近い値となり一方400℃以下
の低温領域（側）では抵抗値が大幅に低下しかつ
Ｂ定数は比較的に第２成分に近い値となつてい
る。このような現象は(a)成分と(b)成分に相互に反
応しない特別の組合わせを選択した場合のみに限
られる。
また(a)成分と(b)成分とが焼結時反応してしまう
組合わせを選択すると、それぞれの成分の特性が
発揮されず、これもまた本発明所期の目的を達成
することができない。
さて上述のような(a)成分と(b)成分とから成る高
温用サーミスタを自動車の触媒マフラー等に用い
るには、例えば実開昭54−49983号に記載されて
いるような耐熱性金属の有底保護筒内にサーミス
タ素子を収納し温度センサーとして使用する。温
度センサーとして使用すると、常温では(b)成分の
働きで抵抗値が500KΩ以下と低く、万一断線が
生じていれば異常に高い抵抗値となり断線の有無
を検知することができる。また700℃〜1000℃で
は(a)成分の働きで抵抗値２〜3KΩ〜0.2〜0.3KΩ
の範囲で温度により変化する。この際(b)成分の抵
抗値は高温時の(a)成分の抵抗値と比較すると無視
できる程度の高さであるため温度測定に実質上弊
害を及ぼさない。
このように１つのサーミスタ素子である焼結体
中で(a)成分と(b)成分とが、あたかも別個の抵抗体
の如く作用するのが、本発明サーミスタの特徴
で、これは焼結体内で(a)成分と(b)成分とが独自の
マトリツクスを形成しているからと考えられる。
以上詳述したように本発明は焼結時反応しない
特定の(a)(b)成分を混合し、同時焼成したものであ
るにもかかわらず、(a)(b)成分を単独で焼成した時
と同様な作用をする。そのためサーミスタ素子に
わざわざ補償抵抗体を固着する必要がなく、製造
が簡単でまた同抵抗体の剥れを心配する必要もな
く、簡単に断線の検知を常温で行うことができ
る。従つて自動車の排ガス浄化装置の温度制御用
として最適なものと言える。[Table] As is clear from Figure 3, when components (a) and (b) coexist, the resistance value remains unchanged or does not decrease significantly in the range of 700 to 900°C or higher (high temperature range), and The constant also has a value close to that of the first component, while in the low temperature region (side) below 400° C., the resistance value decreases significantly and the B constant has a value relatively close to that of the second component. This phenomenon occurs only when a special combination of components (a) and (b) that do not react with each other is selected. Furthermore, if a combination is selected in which components (a) and (b) react during sintering, the characteristics of each component will not be exhibited, and the intended purpose of the present invention cannot be achieved. . Now, in order to use a high-temperature thermistor consisting of components (a) and (b) as described above in a catalyst muffler of an automobile, it is necessary to A thermistor element is housed inside a bottomed protective cylinder and used as a temperature sensor. When used as a temperature sensor, the resistance value is low at room temperature, less than 500KΩ due to the action of component (b), but if a wire breakage occurs, the resistance value will be abnormally high, making it possible to detect the presence or absence of a wire breakage. Also, at 700℃ to 1000℃, the resistance value is 2 to 3KΩ to 0.2 to 0.3KΩ due to the action of component (a).
It varies depending on the temperature within the range. At this time, the resistance value of component (b) is negligible compared to the resistance value of component (a) at high temperatures, so it does not substantially cause any harm to temperature measurement. A feature of the thermistor of the present invention is that the components (a) and (b) act as if they were separate resistors in the sintered body, which is one thermistor element. This is thought to be because component (a) and component (b) form a unique matrix. As detailed above, although the present invention is a mixture of specific components (a) and (b) that do not react during sintering and simultaneous firing, it is possible to fire the components (a) and (b) alone. It acts in the same way as time. Therefore, there is no need to take the trouble to attach a compensation resistor to the thermistor element, manufacturing is simple, there is no need to worry about the resistor peeling off, and disconnection can be easily detected at room temperature. Therefore, it can be said to be optimal for temperature control of automobile exhaust gas purification devices.
第１図は本発明高温用サーミスタの１例を示す
斜視図、第２図は(a)成分として安定化ジルコニア
を用い、(b)成分としてランタンクロマイド化合物
を用いた高温用サーミスタの抵抗と温度の関係を
示す図である。
１……サーミスタ素子、２……リード線。
Figure 1 is a perspective view showing one example of the high temperature thermistor of the present invention, and Figure 2 shows the resistance of a high temperature thermistor using stabilized zirconia as the (a) component and a lanthanum chromide compound as the (b) component. It is a figure showing the relationship of temperature. 1... Thermistor element, 2... Lead wire.
Claims (1)
化物粉末と、小さい抵抗温度係数をもつ第２の金
属酸化物粉末との混合物の焼結体であり、高温域
では、第１の金属酸化物のＢ定数に近いＢ定数を
示し、低温側では第２の金属酸化物のＢ定数に近
いＢ定数を示し、かつ20℃において500KΩ以下
の抵抗値として断線等の異常を検知しうるように
した高温用サーミスタ素子。 ２ 約800℃以上の高温側でＢ定数が8500〓とし
かつ低温側でＢ定数が3000〓以下とした特許請求
の範囲第１項記載の高温用サーミスタ素子。 ３ 第１の金属酸化物が安定化ジルコニアで、第
２の金属酸化物がLa(1-x)CaxCrO3（但しｘ＝０
〜0.2）である特許請求の範囲第１項記載の高温
用サーミスタ素子。[Claims] 1. A sintered body of a mixture of a first metal oxide powder having a large negative temperature coefficient of resistance and a second metal oxide powder having a small temperature coefficient of resistance, and which is sintered in a high temperature range. , shows a B constant close to the B constant of the first metal oxide, shows a B constant close to the B constant of the second metal oxide on the low temperature side, and has a resistance value of 500KΩ or less at 20°C, indicating abnormalities such as disconnection. A high-temperature thermistor element that can detect. 2. The high temperature thermistor element according to claim 1, which has a B constant of 8500 on the high temperature side of about 800°C or higher and 3000 or less on the low temperature side. 3 The first metal oxide is stabilized zirconia, and the second metal oxide is La (1-x) CaxCrO 3 (where x=0
~0.2) The high temperature thermistor element according to claim 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP18835080A JPS57113201A (en) | 1980-12-29 | 1980-12-29 | High temperature thermistor element |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP18835080A JPS57113201A (en) | 1980-12-29 | 1980-12-29 | High temperature thermistor element |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS57113201A JPS57113201A (en) | 1982-07-14 |
| JPS6161684B2 true JPS6161684B2 (en) | 1986-12-26 |
Family
ID=16222078
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP18835080A Granted JPS57113201A (en) | 1980-12-29 | 1980-12-29 | High temperature thermistor element |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS57113201A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0268377U (en) * | 1988-11-10 | 1990-05-23 | ||
| JPH0590659U (en) * | 1992-05-11 | 1993-12-10 | 花王株式会社 | Disk cartridge |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5256897B2 (en) | 2007-08-03 | 2013-08-07 | 三菱マテリアル株式会社 | Metal oxide sintered body for thermistor, thermistor element, thermistor temperature sensor, and method for producing metal oxide sintered body for thermistor |
-
1980
- 1980-12-29 JP JP18835080A patent/JPS57113201A/en active Granted
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0268377U (en) * | 1988-11-10 | 1990-05-23 | ||
| JPH0590659U (en) * | 1992-05-11 | 1993-12-10 | 花王株式会社 | Disk cartridge |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS57113201A (en) | 1982-07-14 |
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