JPH0529104A - Ptc thermistor - Google Patents
Ptc thermistorInfo
- Publication number
- JPH0529104A JPH0529104A JP3179195A JP17919591A JPH0529104A JP H0529104 A JPH0529104 A JP H0529104A JP 3179195 A JP3179195 A JP 3179195A JP 17919591 A JP17919591 A JP 17919591A JP H0529104 A JPH0529104 A JP H0529104A
- Authority
- JP
- Japan
- Prior art keywords
- ptc thermistor
- layer
- thermistor element
- porcelain
- density
- 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.)
- Pending
Links
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- Thermistors And Varistors (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】この発明はＰＴＣサーミスタに関
し、特にたとえば電流制限，消磁またはモータ起動など
に用いられる、ＰＴＣサーミスタに関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a PTC thermistor, and more particularly to a PTC thermistor used for current limiting, degaussing or starting a motor.
【０００２】[0002]
【従来の技術】図５に示す従来のＰＴＣサーミスタ１
は、ＰＴＣサーミスタ素子２を含み、そのＰＴＣサーミ
スタ素子２は単層構造であった。2. Description of the Related Art A conventional PTC thermistor 1 shown in FIG.
Includes a PTC thermistor element 2, and the PTC thermistor element 2 has a single layer structure.
【０００３】[0003]
【発明が解決しようとする課題】ＰＴＣサーミスタ１を
たとえば電流制限に用いる場合、ＰＴＣサーミスタ素子
２が発熱すると、等温線３（電圧印加時におけるサーモ
ビュアで見た等温線）からわかるように、ＰＴＣサーミ
スタ素子２の内部と外表面付近とでは温度差が生じてし
まう。これは、ＰＴＣサーミスタ素子２の外表面付近
は、外気と接触しているため熱拡散が速く温度が低くな
るが、内部では放熱が遅いため、外表面付近と比べて温
度が高くなるからである。When the PTC thermistor 1 is used for current limiting, for example, when the PTC thermistor element 2 generates heat, the PTC thermistor, as can be seen from the isotherm 3 (the isotherm seen by the thermoviewer when voltage is applied). There is a temperature difference between the inside of the element 2 and the vicinity of the outer surface. This is because the vicinity of the outer surface of the PTC thermistor element 2 is in contact with the outside air, so that the heat diffusion is fast and the temperature is low, but the heat dissipation is slow inside, so the temperature is higher than the vicinity of the outer surface. ..
【０００４】したがって、斜線部分４における応力分布
を示す図６（電圧印加時における有限要素法による応力
分布の解析）からわかるように、ＰＴＣサーミスタ素子
２内には圧縮応力および引張応力が発生し、ＰＴＣサー
ミスタ素子２の内部が破壊されることがある。特に、大
きな突入電流が流れる場合、ＰＴＣサーミスタ素子２の
内部と外表面付近との温度差が大きくなるため、破壊が
起こりやすく、したがって破壊特性が悪くなるという問
題点があった。Therefore, as can be seen from FIG. 6 (analysis of the stress distribution by the finite element method when a voltage is applied) showing the stress distribution in the shaded portion 4, compressive stress and tensile stress are generated in the PTC thermistor element 2, The inside of the PTC thermistor element 2 may be destroyed. In particular, when a large inrush current flows, the temperature difference between the inside of the PTC thermistor element 2 and the vicinity of the outer surface of the PTC thermistor element 2 becomes large, so that breakage easily occurs, and thus the breakage characteristics deteriorate.
【０００５】それゆえに、この発明の主たる目的は、破
壊特性のよい、ＰＴＣサーミスタを提供することであ
る。Therefore, a main object of the present invention is to provide a PTC thermistor having good breaking characteristics.
【０００６】[0006]
【課題を解決するための手段】この発明は、多層構造の
ＰＴＣサーミスタ素子を含むＰＴＣサーミスタであっ
て、ＰＴＣサーミスタ素子の内層の密度を最外層の密度
より小さく設定した、ＰＴＣサーミスタである。The present invention is a PTC thermistor including a PTC thermistor element having a multilayer structure, in which the density of the inner layer of the PTC thermistor element is set to be smaller than the density of the outermost layer.
【０００７】[0007]
【作用】ＰＴＣサーミスタ素子の内層の密度を最外層の
密度より小さく設定し、内層をポーラスに形成するの
で、ＰＴＣサーミスタ素子の内層の気孔によりＰＴＣサ
ーミスタ素子内に発生する圧縮応力を吸収する。The density of the inner layer of the PTC thermistor element is set smaller than that of the outermost layer, and the inner layer is formed porous, so that the compressive stress generated in the PTC thermistor element is absorbed by the pores of the inner layer of the PTC thermistor element.
【０００８】[0008]
【発明の効果】この発明によれば、ＰＴＣサーミスタ素
子が発熱しても、ＰＴＣサーミスタ素子内に発生する応
力を小さくできるので、破壊特性が向上する。この発明
の上述の目的，その他の目的，特徴および利点は、図面
を参照して行う以下の実施例の詳細な説明から一層明ら
かとなろう。According to the present invention, even if the PTC thermistor element generates heat, the stress generated in the PTC thermistor element can be reduced, so that the destruction characteristics are improved. The above-mentioned objects, other objects, features and advantages of the present invention will become more apparent from the following detailed description of the embodiments with reference to the drawings.
【０００９】[0009]
【実施例】図１を参照して、この実施例のＰＴＣサーミ
スタ１０は、ＰＴＣサーミスタ素子１２を含む。ＰＴＣ
サーミスタ素子１２は、三層構造の半導体磁器からな
り、最外層となる磁器層１４，内層となる磁器層１６お
よび最外層となる磁器層１８を一体焼成して形成され
る。これら磁器層１４〜１８は基本的には同一材料で構
成される。ただし、磁器層１６の密度は磁器層１４およ
び１８のそれより小さく設定される。ＰＴＣサーミスタ
素子１２の上面および下面には、それぞれ素子電極２０
および２２が形成される。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, a PTC thermistor 10 of this embodiment includes a PTC thermistor element 12. PTC
The thermistor element 12 is made of a three-layered semiconductor porcelain, and is formed by integrally firing the outermost porcelain layer 14, the inner porcelain layer 16 and the outermost porcelain layer 18. These porcelain layers 14 to 18 are basically made of the same material. However, the density of the porcelain layer 16 is set smaller than that of the porcelain layers 14 and 18. On the upper surface and the lower surface of the PTC thermistor element 12, the element electrodes 20 are provided.
And 22 are formed.
【００１０】実験においては、ＰＴＣサーミスタ１０は
以下のようにして製造した。まず、原料配合によって
（Ｂａ0.75Ｓｒ0.25）ＴｉＯ2 を準備し、半導体化剤と
してＹ2 Ｏ3 を０．０５mol ％，鉱化材としてＳｉＯ2
を１．０wt％，特性改善材としてＭｎＯ2 を０．２wt％
添加し、湿式混合後、１１００℃で２時間仮焼する。こ
れに、有機バインダを加えた造粒粉で乾式成形し、図２
に示すような３０mm×３０mm×5mm の角板グリーン体１
４´，および１８´を得る。角板グリーン体１４´およ
び１８´は、後にそれぞれ磁器層１４および磁器層１８
になる。In the experiment, the PTC thermistor 10 was manufactured as follows. First, (Ba 0.75 Sr 0.25 ) TiO 2 is prepared by blending raw materials, and Y 2 O 3 is used as a semiconducting agent in an amount of 0.05 mol% and SiO 2 is used as a mineralizing agent.
Is 1.0 wt% and MnO 2 is 0.2 wt% as a characteristic improving material.
After adding and wet mixing, it is calcined at 1100 ° C. for 2 hours. This is dry-molded with granulated powder with an organic binder added.
30mm x 30mm x 5mm square plate green body 1 as shown in
4'and 18 'are obtained. The square plate green bodies 14 'and 18' will later be formed on the porcelain layer 14 and the porcelain layer 18, respectively.
become.
【００１１】また、同様の手順で作製した仮焼原料に、
有機バインダと直径５μｍのナイロン球とを添加して得
られる造粒粉を乾式成形し、３０mm×３０mm×5mm の角
板グリーン体１６´を得る。角板グリーン体１６´は、
焼成後にポーラス層１６になる。なお、角板グリーン体
１４´，１６´および１８´をそれぞれ１３５０℃で２
時間焼成し、その後鏡面研磨して、画像解析で求めた平
均気孔径と、ＪＩＳＲ２２０５に従って求めた見掛密度
を表１に示す。サンプル数は５個である。Further, for the calcination raw material produced by the same procedure,
The granulated powder obtained by adding an organic binder and nylon balls having a diameter of 5 μm is dry-molded to obtain a square plate green body 16 ′ of 30 mm × 30 mm × 5 mm. The square plate green body 16 '
After firing, it becomes the porous layer 16. In addition, the square plate green bodies 14 ', 16', and 18 'are each heated at 1350 ° C. for 2 hours.
Table 1 shows average pore diameters obtained by image analysis and apparent densities obtained in accordance with JIS R2205 after firing for a time and mirror polishing. The number of samples is 5.
【００１２】[0012]
【表１】 [Table 1]
【００１３】角板グリーン体１４´および１８´の見掛
密度は５．６３g/ccであるのに対し、角板グリーン体１
６´の見掛密度は５．４８g/ccと小さい。そして、図２
に示すように、角板グリーン体１４´，１６´および１
８´を順に積層し、２０００kgｆ／cm2 ，５０℃で６０
秒間熱圧着した後、図３の矢印２４および２６に示す方
向にスライシングし、図４に示すように、チップ状に形
成する。その後、１３５０℃で２時間焼成し、必要に応
じてラップ処理を施し、１２mm×１２mm×３mmのＰＴＣ
サーミスタ素子１２を得る。そして、ＰＴＣサーミスタ
素子１２の上面および下面にそれぞれＩｎ−Ｇａの素子
電極２０および２２を形成した。The apparent density of the square green bodies 14 'and 18' is 5.63 g / cc, whereas the square green body 1 is
The apparent density of 6'is as small as 5.48 g / cc. And FIG.
As shown in FIG. 1, square green bodies 14 ', 16' and 1
8'is laminated in order, 2000 kgf / cm 2 , 60 at 50 ° C
After thermocompression bonding for 2 seconds, slicing is performed in the directions indicated by arrows 24 and 26 in FIG. 3 to form chips as shown in FIG. After that, it is baked at 1350 ° C for 2 hours, lapped if necessary, and it is a PTC of 12mm x 12mm x 3mm.
The thermistor element 12 is obtained. Then, In—Ga element electrodes 20 and 22 were formed on the upper surface and the lower surface of the PTC thermistor element 12, respectively.
【００１４】上述のＰＴＣサーミスタ素子１２について
電気特性を測定すると、表２の上欄に示す結果が得ら
れ、破壊特性は５６０Ｖであった。When the electrical characteristics of the PTC thermistor element 12 described above were measured, the results shown in the upper column of Table 2 were obtained, and the breakdown characteristic was 560V.
【００１５】[0015]
【表２】 [Table 2]
【００１６】比較のため、従来と同様の単層構造のＰＴ
Ｃサーミスタ素子を形成する。まず、角状グリーン体１
４´や１８´を作成する際の原料を用い、乾式成形によ
って、１５mm×１５mm×５mmの角板グリーン体とする。
その後、１３５０℃で２時間焼成し、必要に応じてラッ
プ処理を施し、１２mm×１２mm×３mmの大きさのＰＴＣ
サーミスタ素子を形成する。そして、このＰＴＣサーミ
スタ素子の両主面にＩｎ−Ｇａ電極を形成して電気特性
を測定すると、表２の下欄に示す結果が得られ、破壊特
性は４８０Ｖであった。表２におけるサンプル数は１０
個である。For comparison, a PT having a single-layer structure similar to the conventional one
A C thermistor element is formed. First, the angular green body 1
Using the raw materials used to make 4'and 18 ', dry-molding is performed to obtain a rectangular plate green body of 15 mm x 15 mm x 5 mm.
After that, it is baked at 1350 ° C for 2 hours, lapped if necessary, and the size of PTC is 12mm x 12mm x 3mm.
Form the thermistor element. When In-Ga electrodes were formed on both main surfaces of this PTC thermistor element and the electrical characteristics were measured, the results shown in the lower column of Table 2 were obtained, and the breakdown characteristics were 480V. The number of samples in Table 2 is 10
It is an individual.
【００１７】表２に示す結果から、ＰＴＣサーミスタ素
子１２のように、磁器層１４および１８より密度の小さ
いすなわちポーラスに形成した磁器層１６を内層に用い
ることにより、破壊特性が向上する。なお、上述の実施
例では、ＰＴＣサーミスタ素子１２を３層構造として形
成したが、４層以上の構造にし、最外層から中央の層に
向かうに従って密度を減少させるものでもよい。また、
ＰＴＣサーミスタ素子１２を４層以上の構造にした場
合、各内層の密度が最外層の見掛密度より小さければ、
各内層の密度を等しく設定してもよい。From the results shown in Table 2, when the PTC thermistor element 12 has a lower density than the ceramic layers 14 and 18, that is, a porous ceramic layer 16 is used as the inner layer, the fracture characteristics are improved. Although the PTC thermistor element 12 has a three-layer structure in the above-described embodiments, it may have a structure of four or more layers, and the density may be reduced from the outermost layer toward the central layer. Also,
When the PTC thermistor element 12 has a structure of four or more layers, if the density of each inner layer is smaller than the apparent density of the outermost layer,
You may set the density of each inner layer equally.
【００１８】さらに、ＰＴＣサーミスタ素子１２を多層
構造とせずに、単層構造とし、その中心部に向かって密
度を減少させるものでもよい。Further, the PTC thermistor element 12 may have a single-layer structure instead of a multi-layer structure, and the density thereof may be reduced toward the center thereof.
【図１】この発明の一実施例を示す断面図である。FIG. 1 is a sectional view showing an embodiment of the present invention.
【図２】この実施例の製造工程において、角板グリーン
体を積層し、熱圧着する状態を示す図解図である。FIG. 2 is an illustrative view showing a state in which rectangular plate green bodies are stacked and thermocompression bonded in the manufacturing process of this example.
【図３】角板グリーン体を熱圧着した後スライシングす
る状態を示す斜視図である。FIG. 3 is a perspective view showing a state where the rectangular plate green body is subjected to thermocompression bonding and then sliced.
【図４】角板グリーン体をスライシングした後チップ状
に形成した状態を示す斜視図である。FIG. 4 is a perspective view showing a state where a rectangular plate green body is sliced and then formed into a chip shape.
【図５】従来のＰＴＣサーミスタを示す断面図解図であ
る。FIG. 5 is a schematic cross-sectional view showing a conventional PTC thermistor.
【図６】従来のＰＴＣサーミスタ素子に生じる圧縮応力
および引張応力の分布を示す図解図である。FIG. 6 is an illustrative view showing distributions of compressive stress and tensile stress generated in a conventional PTC thermistor element.
１０ …ＰＴＣサーミスタ １２ …ＰＴＣサーミスタ素子 １４，１６，１８…磁器層 ２０，２２ …素子電極 10 ... PTC thermistor 12 ... PTC thermistor element 14, 16, 18 ... Porcelain layer 20, 22 ... Element electrode
Claims (1)
ＴＣサーミスタであって、 前記ＰＴＣサーミスタ素子の内層の密度を最外層の密度
より小さく設定した、 ＰＴＣサーミスタ。Claims: 1. A P containing a PTC thermistor element having a multilayer structure.
A TC thermistor, wherein the density of the inner layer of the PTC thermistor element is set lower than the density of the outermost layer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3179195A JPH0529104A (en) | 1991-07-19 | 1991-07-19 | Ptc thermistor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3179195A JPH0529104A (en) | 1991-07-19 | 1991-07-19 | Ptc thermistor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0529104A true JPH0529104A (en) | 1993-02-05 |
Family
ID=16061597
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3179195A Pending JPH0529104A (en) | 1991-07-19 | 1991-07-19 | Ptc thermistor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0529104A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0751539A2 (en) * | 1995-06-29 | 1997-01-02 | Murata Manufacturing Co., Ltd. | Positive characteristics thermistor device |
| CN1087866C (en) * | 1995-12-13 | 2002-07-17 | 株式会社村田制作所 | Positive characteristics thermistor device |
| WO2008123078A1 (en) * | 2007-03-19 | 2008-10-16 | Murata Manufacturing Co., Ltd. | Laminated positive temperature coefficient thermistor |
| WO2012036142A1 (en) * | 2010-09-17 | 2012-03-22 | 株式会社 村田製作所 | Positive characteristic thermistor and method for manufacturing positive characteristic thermistor |
-
1991
- 1991-07-19 JP JP3179195A patent/JPH0529104A/en active Pending
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0751539A2 (en) * | 1995-06-29 | 1997-01-02 | Murata Manufacturing Co., Ltd. | Positive characteristics thermistor device |
| EP0751539A3 (en) * | 1995-06-29 | 1997-05-28 | Murata Manufacturing Co | Positive characteristics thermistor device |
| US5790011A (en) * | 1995-06-29 | 1998-08-04 | Murata Manufacturing Co., Ltd. | Positive characteristics thermistor device with a porosity occupying rate in an outer region higher than that of an inner region |
| CN1081384C (en) * | 1995-06-29 | 2002-03-20 | 株式会社村田制作所 | Positive-property thermal-sensitive electric resistance device |
| CN1087866C (en) * | 1995-12-13 | 2002-07-17 | 株式会社村田制作所 | Positive characteristics thermistor device |
| WO2008123078A1 (en) * | 2007-03-19 | 2008-10-16 | Murata Manufacturing Co., Ltd. | Laminated positive temperature coefficient thermistor |
| JPWO2008123078A1 (en) * | 2007-03-19 | 2010-07-15 | 株式会社村田製作所 | Multilayer positive temperature coefficient thermistor |
| WO2012036142A1 (en) * | 2010-09-17 | 2012-03-22 | 株式会社 村田製作所 | Positive characteristic thermistor and method for manufacturing positive characteristic thermistor |
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