JPH0663895B2 - Ceramic pressure sensor and manufacturing method thereof - Google Patents
Ceramic pressure sensor and manufacturing method thereofInfo
- Publication number
- JPH0663895B2 JPH0663895B2 JP3304048A JP30404891A JPH0663895B2 JP H0663895 B2 JPH0663895 B2 JP H0663895B2 JP 3304048 A JP3304048 A JP 3304048A JP 30404891 A JP30404891 A JP 30404891A JP H0663895 B2 JPH0663895 B2 JP H0663895B2
- Authority
- JP
- Japan
- Prior art keywords
- pressure
- ceramic
- thickness
- diaphragm body
- pressure responsive
- 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 - Lifetime
Links
Description
【発明の詳細な説明】
【０００１】
【産業上の利用分野】本発明は、薄肉なセラミックから
なる圧力応動部に応力検知センサを付設して該圧力応動
部に作用する圧力を電気信号に変換するセラミック圧力
センサ及びその製造方法に関する。
【０００２】
【従来の技術】近時、自動車のエンジン等においては、
マイクロコンピュータを用いて運転制御を行うようにし
たものがあり、そこで、例えばエンジンの吸入空気圧等
の圧力変化の検出を、単一の設定圧で作用する圧力スイ
ッチで行ったのでは、充分な運転制御ができないので、
圧力変化を連続的な電気信号として出力することのでき
る圧力センサが要望されている。
【０００３】この要望に対処するため、化学的に安定で
且つ耐熱性が良好なセラミック製のダイアフラムを用い
た圧力センサが試作研究されている。このものは、厚肉
な環状のセラミックからなる台座部の一面に、薄肉なセ
ラミックからなる圧力応動部をガラス等で接着し、前記
圧力応動部に応力検出センサを付設して構成されてい
る。
【０００４】
【発明が解決しようとする課題】しかしながら、上記従
来のものでは、台座部と圧力応動部とが別体であるた
め、それらの接着部分の機械的強度が母材に比べて低
く、シーリング（気密保持）が悪く、且つ、圧力応動部
を十分に薄く（例えば０．２mm以下）することは極めて
困難で、そのため感度を高めるためには面積を大きくす
る必要があるので小形化ができないという欠点がある。
【０００５】本発明は上記事情に鑑みてなされたもの
で、その目的は、台座部と圧力応動部との間の接着によ
る接合部分をなくして機械的強度の向上及びシーリング
の飛躍的な改善を図ると共に、圧力応動部の極薄化によ
る感度向上及び小形化を図ることができるセラミック圧
力センサ及びその製造方法を提供するにある。
【０００６】
【課題を解決するための手段】本発明のセラミック圧力
センサは、セラミック材料の加圧，焼成により最終形状
よりも厚み寸法を増大させた状態で一体成形した後研削
して形成され厚肉な台座部の内側に厚さ約０．２ｍｍ以
下の薄肉な圧力応動部を一体に備えるセラミックダイア
フラム本体と、このセラミックダイアフラム本体の前記
圧力応動部に付設された応力検知センサと、前記セラミ
ックダイアフラム本体に設けられ前記応力検知センサに
直結されてその出力信号を取り出すための厚膜回路又は
薄膜回路からなる電気回路とを具備し、前記圧力応動部
の半径ａ、圧力応動部の厚さｔ（約０．２ｍｍ以下）、
前記台座部の外周半径ｂ、台座部の厚さｃが、 ｃ≧１０ｔ、ｂ≧ａ＋１０ｔ の寸法関係とされ、且つ台座部の内径部と圧力応動部と
の間が曲率半径Ｒが約０．５ｍｍの円弧面によって連な
っている
ところに特徴を有する。
【０００７】また、本発明のセラミック圧力センサの製
造方法は、セラミックダイアフラム本体の素材をセラミ
ック材料の加圧，焼成により最終形状よりも厚み寸法を
増大させた状態で成形した後、前記素材を研削加工する
ことにより、厚肉な台座部の内側に厚さ約０．２ｍｍ以
下の薄肉な圧力応動部を一体に備えると共に、圧力応動
部の半径ａ、圧力応動部の厚さｔ（約０．２ｍｍ以
下）、前記台座部の外周半径ｂ、台座部の厚さｃが、 ｃ≧１０ｔ、ｂ≧ａ＋１０ｔ の寸法関係とされ、且つ台座部の内径部と圧力応動部と
の間が曲率半径Ｒが約０．５ｍｍの円弧面によって連な
った形状のセラミックダイアフラム本体を形成し、この
後、セラミックダイアフラム本体の圧力応動部に応力検
知センサを付設すると共に、前記セラミックダイアフラ
ム本体に、前記応力検知センサに直結されてその出力信
号を取り出すための厚膜回路又は薄膜回路からなる電気
回路を設けるようにしたところに特徴を有する。
【０００８】
【作用】上記手段によれば、セラミックダイアフラム本
体は、台座部及び圧力応動部をセラミック材料の加圧，
焼成により一体成形して構成されているので、台座部と
圧力応動部との間に接着による接合部分がなくなる。こ
れにより、機械的強度及びシーリング性を向上させるこ
とができる。
【０００９】そして、セラミックダイアフラム本体は、
セラミック材料の加圧，焼成後に切削して構成されるの
で、台座部と圧力応動部との厚みの差が大きいものであ
っても容易に一体成形でき、しかも圧力応動部の極薄化
を図ることができる。
【００１０】さらに、セラミックダイアフラム本体の各
部の寸法関係を、上述のように形成することにより、圧
力が作用したときの圧力応動部の歪みに比べて、その周
囲の台座部の歪みを無視し得る程度に小さくでき、ま
た、厚みが急激に変化する台座部と圧力応動部との境界
部分に応力の過大な集中が生ずることを防止することが
できる。
【００１１】
【実施例】以下、本発明の第１の実施例について、図１
乃至図７を参照しながら説明する。１はセラミックダイ
アフラム本体であり、これは、セラミック材料として例
えば９６％〜９９％のアルミナ（Ａｌ2 Ｏ3 ）を用い、
これを加圧成形及び焼成することによって形成されてい
る。このセラミックダイアフラム本体１は、厚肉でこの
場合円環状をなす台座部２の内側に、薄肉で円形をなす
圧力応動部３を一体に備えて構成され、前記台座部２の
上面２ａが圧力応動部３の上面３ａに同一平面で連続し
た形状を呈している。
【００１２】そして、このセラミックダイアフラム本体
１は、図１に示すように、圧力応動部３の半径をａ、厚
さをｔ、前記台座部２の外周半径をｂ、厚さをｃとし、
台座部２の内径部と圧力応動部３との境界部分の曲率半
径をＲとしたときに、
【００１３】ｃ≧１０ｔ、ｂ≧ａ＋１０ｔ、ｔ≦０．２
ｍｍ、Ｒ＝０．５ｍｍ
の条件を満たすように形成されている。
【００１４】これらの条件は、セラミックダイアフラム
１の圧力応動部３に圧力が印加された時に、圧力応動部
３の歪みに比べて、その周囲の台座部２の歪みが無視し
得る程度に小さく、また、厚さが急激に変化する台座部
２と圧力応動部３との境界部分に、応力の過大な集中が
生じないように夫々設定されている。また、圧力応動部
３の半径ａ及び厚さｔは、該圧力応動部３に印加される
最大定格圧力と、該圧力応動部３の材質とにより決定さ
れる。
【００１５】即ち、圧力Ｐが圧力応動部３に印加された
時に生ずる最大応力δmax は、
【００１６】
【数１】
δmax＝（δｒ）r=a＝０．７５・Ｐａ2／ｔ2
で求められる。この最大応力δｍａｘが圧力応動部３の
材料の強度δＢを越えないように厚さｔ及び半径ａを決
定するのであるが、セラミック製品は機械的強度のばら
つきが比較的大きいから、δｍａｘがδＢの１／４〜１
／１０とするのが望ましく、これらは製造技術，求めら
れる製品の寸法及び圧力応動部３に付設される後述する
応力検知センサのゲージファクタの大きさ等も考慮して
定められるものである。
【００１７】而して、セラミックダイアフラム本体１を
製作する場合に、セラミック材料を加圧成形し焼成する
ことにより、図１に示す最終形状を直ちに得ることが最
も加工工程を単純化し得るのであるが、この形状を直ち
に得ようとすると、台座部２と圧力応動部３との間の厚
さの差が大きいため、加圧成形時に全体を一定の加圧力
で成形することが困難で、均一で緻密な製品が得られな
い事情がある。
【００１８】そこで、本実施例では、図３に示すよう
に、台座部２及び圧力応動部３の厚さ寸法を上面２ａ及
び３ａ側に増加させた状態にて加圧成形及び焼成を行っ
て素材を形成し、この後に、その素材を同図に破線で示
すように切削或いは研磨加工して最終形状寸法を得るこ
とにより、全体が緻密で均一なセラミックダイアフラム
本体１を得るようにしているのである。
【００１９】さて、４乃至７は応力検知センサであり、
これは、圧力応動部３の上面３ａの中心部及び外周部に
酸化ルテニウム（ＲｕＯ2 ）系の抵抗材を印刷及び焼成
することにより形成されたピエゾレジスティブな厚膜抵
抗からなる。これら応力検知センサ４〜７は印刷導体に
より図２及び図４に示すようにブリッジ接続され、これ
にて、応力検知センサ４〜７の出力信号を取り出すため
の電気回路８が形成されており、前記印刷導体の所要部
所には、面積を拡大した電源端子部８ａ，８ｂ及び出力
端子部８ｃ，８ｄが夫々形成されている。尚、セラミッ
クダイアフラム本体１は、耐熱性に優れたセラミック製
であるので、膜回路形成時の高温にも十分に耐え得る。
【００２０】次に、上記構成の作用について説明する。
セラミックダイアフラム本体１の圧力応動部３の下面側
に、図１にＰで示す圧力が上向きに作用すると、圧力Ｐ
に比例して圧力応動部３の中心部分には引張応力が作用
し、且つ外周部分には圧縮応力が作用する。
【００２１】即ち、圧力応動部３の中心から外周に向う
半径方向の応力分布は、図５に示すようになり、中心部
（ｒ＝０）で引張応力が最大となり、外周部（ｒ＝ａ）
で圧縮応力が最大となる。そして、これらの応力δν
は、
【００２２】
【数２】
（δｒ）r=a＝０．４５・Ｐａ2／ｔ2
（δｒ）r=a＝０．７５・Ｐａ2／ｔ2
（ポアソン比ν＝０．２）
で示される。
【００２３】一方、圧力応動部３の中心部分及び外周部
分に形成された応力検知センサ４〜７には、該圧力応動
部３に作用する応力に応じて図６に示すような抵抗値の
変化が生じ、応力検知センサ４〜７がブリッジ接続され
ていることにより、電源端子部８ａ，８ｂに電圧値一定
の電源電圧Ｖinを印加すると、出力端子部８ｃ，８ｄに
図７に示すような圧力Ｐに比例した出力電圧Ｖout が得
られる。
【００２４】ちなみに、出願人は、セラミック材料とし
て９６％アルミナを用い、厚さｔ＝０．２mm，半径ａ＝
６．５mmに定め、その他の寸法ｂ，ｃ及びＲは上記した
条件を満足するように定めてセラミックダイアフラム本
体１を形成し、ゲージファクタが１８の酸化ルテニウム
系の厚膜抵抗体により応力検知センサ４〜７を製作し、
電源電圧Ｖinに５Ｖ，印加圧力Ｐ＝５Ｋｇ／cm2 の時
に、出力電圧Ｖout ＝４５ｍＶ（出力感度９ｍＶ）の圧
力センサを得ることができた。
【００２５】上記構成では、厚肉な台座部２５及び薄肉
な圧力応動部３をセラミック材料による一体成形により
セラミックダイアフラム本体１を形成したから、従来の
ガラスにより接着していたものと異なり、台座部２と圧
力応動部３との間に接着による接合部分がなくなる。こ
れにより、機械的強度及びシーリング性を飛躍的に向上
させることができる。
【００２６】そして、これと共に、セラミックダイアフ
ラム本体１は、厚み寸法を増大させた状態で加圧成形及
び焼成を行った後に研削して構成されるので、台座部２
と圧力応動部３との厚みの差が大きいものであっても容
易に一体成形でき、しかも圧力応動部３の極薄化ひいて
は全体の小形化を図ることができるものである。ちなみ
に、圧力応動部３の厚さを例えば０．２mmから０．１mm
と半分にすれば、前述した数式から理解されるように、
同一圧力で発生する応力を減少させることなく圧力応動
部３の径寸法を１／４にすることができる。
【００２７】さらに、セラミックダイアフラム本体１の
各部の寸法関係を、特許請求の範囲に記載された通りに
形成したことにより、圧力が作用したときの圧力応動部
３の歪みに比べて、その周囲の台座部２の歪みを無視し
得る程度に小さくでき、また、厚みが急激に変化する台
座部２と圧力応動部３との境界部分に応力の過大な集中
が生ずることを防止することができるのである。
【００２８】尚、応力検知センサ４〜７は、印刷及び焼
成により形成される厚膜回路の他に、蒸着或いはスパッ
タリングにより形成される薄膜回路によって構成しても
よく、同様に印刷導体の代りに薄膜回路により応力検知
センサ４〜７からの出力信号を取り出すための電気回路
８を構成してもよい。
【００２９】図８及び図９は本発明の第２の実施例を示
すものであり、上記第１の実施例と異なるところは、圧
力応動部３の代りに円環状の圧力応動部９と該圧力応動
部９の中心部に位置された厚肉な円形の台座部１０とを
台座部２に一体にセラミック材料により形成することに
よって、セラミックダイアフラム本体１１を製作するよ
うにしたものである。
【００３０】そして、応力検知センサ４〜７を前記圧力
応動部９の内周部と外周部とに夫々付設するとともに、
図示はしないが台座部１０の上面側に、応力検知センサ
４〜７に直結させてその出力信号処理を行う例えば厚膜
ハイブリッドＩＣ回路からなる電気回路としての信号処
理回路が構築されている。
【００３１】このような構成でも上記第１の実施例と同
様の作用効果が得られ、応力検知センサ４〜７を厚膜回
路によって形成する場合には、これらを厚膜ハイブリッ
ドＩＣ回路を構築する焼成の過程を共通にして製作する
ことができ、製造工程が簡便になる。また、このように
応力検知センサ４〜７の出力信号処理を行う信号処理回
路を台座部１０の上面側に直結して付設することによ
り、接続等の信頼性が向上し、小形化，高密度化を図る
ことができ、更にセンサ部分の零点及び出力感度の調整
も合せて行うことができ、従来のものより全体の回路の
信頼性向上及び製作調整の容易化が可能となる。
【００３２】図１０及び図１１は本発明の第３の実施例
を、図１２及び図１３は本発明の第４の実施例を夫々示
すものであり、上記第１の実施例とは次の点で異なる。
【００３３】即ち、円環状の台座部２の代りに、該台座
部２よりも面積が大きな台座部１２及び１３を圧力応動
部３と一体にセラミック材料で形成することによってセ
ラミックダイアフラム本体１４及び１５を夫々製作し、
台座部１２及び１３の上面側に、上記第２の実施例と同
様に応力検知センサ４〜７に直結させてその出力信号処
理を行う例えば厚膜回路からなる信号処理回路を付設し
た構成である。この信号処理回路を、第２の実施例と同
様に例えばハイブリッドＩＣ回路により製作することに
より、第１の実施例の効果に合せて、第２の実施例と同
様の効果を奏するものである。
【００３４】尚、上記各実施例において、セラミックダ
イアフラム本体１，１１，１４及び１５は、アルミナに
限られず、一体成形が可能で緻密であり且つ機械的な強
度が満足されるもので、応力検知センサの特性に整合し
得るものであれば、他の材質でもよく、また、上記した
実施例の厚膜回路又は薄膜回路からなる応力検出センサ
の代りに別途に製作されたストレンゲージのように歪み
を電気信号に変換する既製のセンサを接着等によって圧
力応動部３の所定位置に貼着するようにしてもよい。
【００３５】
【発明の効果】以上の説明から明らかなように、本発明
のセラミック圧力センサ及びその製造方法によれば、セ
ラミックダイアフラム本体をセラミック材料の加圧，焼
成により一体成形して構成したので、台座部と圧力応動
部との間に接着による接合部分がなくなり、機械的強度
の向上及びシーリングの飛躍的な改善を図ることがで
き、また、セラミックダイアフラム本体をセラミック材
料の加圧，焼成後に切削して構成するようにしたので、
圧力応動部の極薄化を図ることができて感度向上及び小
形化を図ることができ、さらにはダイアフラム本体の各
部を最適な寸法関係としたことにより、感度のより一層
の向上及び耐久性の向上を図ることができるという優れ
た効果を奏するものである。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure responsive section made of thin ceramics and is provided with a stress detecting sensor to convert the pressure acting on the pressure responsive section into an electric signal. Ceramic pressure sensor and its manufacturing method . 2. Description of the Related Art Recently, in automobile engines and the like,
There is a system in which operation control is performed by using a microcomputer. Therefore, for example, if a pressure switch acting at a single set pressure is used to detect a pressure change such as engine intake air pressure, a sufficient operation is possible. I can't control it,
There is a demand for a pressure sensor that can output a pressure change as a continuous electric signal. In order to meet this demand, a pressure sensor using a ceramic diaphragm, which is chemically stable and has good heat resistance, has been experimentally researched. This is configured such that a pressure responsive portion made of thin ceramic is bonded to one surface of a pedestal portion made of thick annular ceramic with glass or the like, and a stress detection sensor is attached to the pressure responsive portion. However, in the above-mentioned conventional one, since the pedestal portion and the pressure responsive portion are separate bodies, the mechanical strength of their bonded portion is lower than that of the base material, Sealing (airtightness) is poor, and it is extremely difficult to make the pressure responsive part sufficiently thin (for example, 0.2 mm or less). Therefore, it is necessary to increase the area in order to increase the sensitivity, so it cannot be miniaturized. There is a drawback that. The present invention has been made in view of the above circumstances, and it is an object of the present invention to improve the mechanical strength and dramatically improve the sealing by eliminating the joint portion by adhesion between the pedestal portion and the pressure responsive portion. Another object of the present invention is to provide a ceramic pressure sensor and a method for manufacturing the same, which can improve the sensitivity and downsize by making the pressure response portion extremely thin. A ceramic pressure sensor of the present invention is formed by integrally molding the ceramic material in a state where the thickness dimension is increased from the final shape by pressurizing and firing the ceramic material and then grinding the thickness. Thickness of 0.2mm or less inside the pedestal
A ceramic diaphragm body integrally provided with a lower thin pressure responsive section, a stress detection sensor attached to the pressure responsive section of the ceramic diaphragm body, and a ceramic diaphragm body provided directly on the stress detection sensor. An electric circuit including a thick film circuit or a thin film circuit for extracting an output signal, the radius a of the pressure responsive portion, the thickness t of the pressure responsive portion (about 0.2 mm or less) ,
The outer peripheral radius b of the pedestal portion and the thickness c of the pedestal portion have a dimensional relationship of c ≧ 10t, b ≧ a + 10t , and the inner diameter portion of the pedestal portion and the pressure response portion are
Are connected by an arc surface with a radius of curvature R of about 0.5 mm.
There is a feature in that. Further , the ceramic pressure sensor of the present invention is manufactured.
The manufacturing method is ceramic material
By pressing and firing the material
After forming in the increased state, grind the material
As a result, a thickness of about 0.2 mm or less can be placed inside the thick pedestal.
It is equipped with a thin pressure response part below, and
Radius a, thickness t of pressure responsive part (about 0.2 mm or less
Lower), the outer peripheral radius b of the pedestal portion and the thickness c of the pedestal portion are dimensional relations of c ≧ 10t, b ≧ a + 10t , and the inner diameter portion of the pedestal portion and the pressure response portion are
Are connected by an arc surface with a radius of curvature R of about 0.5 mm.
Form a ceramic diaphragm body with a
After that, stress detection is performed on the pressure response part of the ceramic diaphragm body.
An intelligent sensor is attached and the ceramic diaphragm
The output signal of the stress detection sensor directly connected to the
Of a thick film circuit or thin film circuit for extracting the signal
It is characterized in that a circuit is provided. According to the above-mentioned means, the ceramic diaphragm main body has the pedestal portion and the pressure responsive portion for pressing the ceramic material,
Since it is integrally formed by firing, there is no bonded portion between the pedestal portion and the pressure responsive portion due to adhesion. Thereby, the mechanical strength and the sealing property can be improved. The ceramic diaphragm body is
Since the ceramic material is cut and pressed and then cut, it can be easily integrally molded even if there is a large difference in thickness between the pedestal part and the pressure responsive part, and the pressure responsive part can be made extremely thin. be able to. Further, by forming the dimensional relationship of each part of the ceramic diaphragm body as described above, the strain of the pedestal part around the pressure responsive part can be ignored compared to the strain of the pressure responsive part when pressure is applied. It is possible to reduce the size to a small extent, and it is possible to prevent the stress from being excessively concentrated at the boundary portion between the pedestal portion and the pressure responsive portion where the thickness changes abruptly. The first embodiment of the present invention will be described below with reference to FIG.
It will be described with reference to FIGS. 1 is a ceramic diaphragm body, which uses, for example, 96% to 99% alumina (Al2 O3) as a ceramic material,
It is formed by pressure molding and firing. The ceramic diaphragm body 1 is configured by integrally including a thin and circular pressure responsive portion 3 inside a thick and circular annular pedestal portion 2 in this case, and the upper surface 2a of the pedestal portion 2 is pressure responsive. The upper surface 3a of the portion 3 has a continuous shape on the same plane. As shown in FIG. 1, the ceramic diaphragm body 1 has a radius of the pressure responsive portion 3 of t, a thickness of t, an outer peripheral radius of the pedestal portion 2 of b, and a thickness of c.
When the radius of curvature of the boundary portion between the inner diameter portion of the pedestal portion 2 and the pressure responsive portion 3 is R, then c ≧ 10t, b ≧ a + 10t, t ≦ 0.2
mm and R = 0.5 mm are satisfied. These conditions are such that when pressure is applied to the pressure responsive portion 3 of the ceramic diaphragm 1, the strain of the pedestal portion 2 around the pressure responsive portion 3 is so small that it can be ignored, as compared with the strain of the pressure responsive portion 3. Further, the stress is set so as not to be excessively concentrated at the boundary between the pedestal portion 2 and the pressure responsive portion 3 where the thickness changes abruptly. The radius a and the thickness t of the pressure responsive portion 3 are determined by the maximum rated pressure applied to the pressure responsive portion 3 and the material of the pressure responsive portion 3. That is, the maximum stress δmax generated when the pressure P is applied to the pressure responsive section 3 is obtained by the following equation: δmax = (δr) r = a = 0.75 · Pa 2 / t 2 . To be The thickness t and the radius a are determined so that the maximum stress δmax does not exceed the strength δB of the material of the pressure responsive portion 3. However, since the ceramic products have a relatively large variation in mechanical strength, δmax is δB. 1/4 to 1
/ 10 is desirable, and these are determined in consideration of the manufacturing technique, the required product size, and the size of the gauge factor of the stress detection sensor described later attached to the pressure responsive portion 3. Thus, when the ceramic diaphragm body 1 is manufactured, it is most possible to simplify the processing step by immediately obtaining the final shape shown in FIG. 1 by press-molding and firing the ceramic material. However, if it is attempted to obtain this shape immediately, it is difficult to form the whole body with a constant pressing force at the time of pressure forming because the difference in thickness between the pedestal portion 2 and the pressure responsive portion 3 is large, and it is uniform. There are circumstances in which precise products cannot be obtained. [0018] Therefore, in this embodiment, as shown in FIG. 3, Tsu line pressure molding and sintering in a state in which the thickness of the base portion 2 and the pressure responding portion 3 is increased to the upper surface 2a and 3a side
Then, the material is formed, and thereafter, the material is cut or polished as shown by a broken line in the figure to obtain the final shape and dimension, thereby obtaining the ceramic diaphragm body 1 which is dense and uniform as a whole. Of. Now, 4 to 7 are stress detection sensors,
This is a piezoresistive thick film resistor formed by printing and firing a ruthenium oxide (RuO2) -based resistance material on the central portion and the outer peripheral portion of the upper surface 3a of the pressure responsive portion 3. These stress detecting sensors 4 to 7 are bridge-connected by printed conductors as shown in FIGS. 2 and 4, and thereby an electric circuit 8 for extracting output signals of the stress detecting sensors 4 to 7 is formed. Power supply terminal portions 8a, 8b and output terminal portions 8c, 8d having an enlarged area are formed at required portions of the printed conductor. Since the ceramic diaphragm body 1 is made of ceramic having excellent heat resistance, it can sufficiently withstand high temperatures during the formation of the membrane circuit. Next, the operation of the above configuration will be described.
When the pressure P shown in FIG. 1 acts upward on the lower surface side of the pressure responsive portion 3 of the ceramic diaphragm body 1, the pressure P
In proportion to, a tensile stress acts on the central portion of the pressure responsive portion 3, and a compressive stress acts on the outer peripheral portion. That is, the stress distribution in the radial direction from the center of the pressure responsive portion 3 to the outer periphery is as shown in FIG. 5, in which the tensile stress is maximum at the central portion (r = 0) and the outer peripheral portion (r = a). )
The compressive stress becomes maximum at. And these stress δν
Is the following: (δr) r = a = 0.45 · Pa 2 / t 2 (δr) r = a = 0.75 · Pa 2 / t 2 (Poisson's ratio ν = 0.2) Indicated by. On the other hand, in the stress detecting sensors 4 to 7 formed in the central portion and the outer peripheral portion of the pressure responsive portion 3, the resistance value changes as shown in FIG. 6 according to the stress acting on the pressure responsive portion 3. When the power supply voltage Vin having a constant voltage value is applied to the power supply terminal portions 8a and 8b due to the bridge connection of the stress detection sensors 4 to 7, pressures as shown in FIG. 7 are applied to the output terminal portions 8c and 8d. An output voltage Vout proportional to P is obtained. By the way, the applicant uses 96% alumina as the ceramic material and has a thickness t = 0.2 mm and a radius a =
The thickness of the ceramic diaphragm body 1 is set to 6.5 mm, and the other dimensions b, c and R are set so as to satisfy the above-mentioned conditions, and a stress detection sensor is formed by a ruthenium oxide-based thick film resistor having a gauge factor of 18. Produce 4-7,
When the power supply voltage Vin was 5 V and the applied pressure P was 5 kg / cm @ 2, a pressure sensor having an output voltage Vout of 45 mV (output sensitivity of 9 mV) could be obtained. In the above structure, since the ceramic diaphragm body 1 is formed by integrally molding the thick pedestal portion 25 and the thin pressure responsive portion 3 with the ceramic material, unlike the conventional glass-bonded portion, the pedestal portion is bonded. There is no bonded portion between the pressure-responsive portion 3 and the pressure-responsive portion 3. Thereby, the mechanical strength and the sealing property can be dramatically improved. Along with this, the ceramic diaphragm main body 1 is constructed by performing pressure molding and firing with the thickness dimension increased and then grinding.
Even if there is a large difference in thickness between the pressure responsive portion 3 and the pressure responsive portion 3, the pressure responsive portion 3 can be easily integrally formed, and further, the pressure responsive portion 3 can be made extremely thin and thus the overall size can be reduced. By the way, the thickness of the pressure response part 3 is, for example, 0.2 mm to 0.1 mm.
If you halve it, as can be understood from the above formula,
The diameter of the pressure responsive portion 3 can be reduced to 1/4 without reducing the stress generated at the same pressure. Further, the dimensional relationship of each part of the ceramic diaphragm body 1 is formed as described in the claims, so that the peripheral portion of the pressure responsive portion 3 is compared with the strain of the pressure responsive portion 3 when a pressure is applied. Since the strain of the pedestal portion 2 can be reduced to a negligible degree, and it is possible to prevent excessive concentration of stress at the boundary portion between the pedestal portion 2 and the pressure responsive portion 3 where the thickness changes abruptly. is there. The stress detecting sensors 4 to 7 may be formed by a thin film circuit formed by vapor deposition or sputtering in addition to the thick film circuit formed by printing and firing. The electric circuit 8 for extracting the output signals from the stress detection sensors 4 to 7 may be configured by a thin film circuit. FIGS. 8 and 9 show a second embodiment of the present invention. The difference from the first embodiment is that instead of the pressure responsive portion 3, an annular pressure responsive portion 9 and the pressure responsive portion 9 are provided. A ceramic diaphragm body 11 is manufactured by integrally forming a thick circular pedestal portion 10 located at the center of the pressure responsive portion 9 on the pedestal portion 2 with a ceramic material. The stress detecting sensors 4 to 7 are attached to the inner peripheral portion and the outer peripheral portion of the pressure responsive portion 9, respectively, and
Although not shown, on the upper surface side of the pedestal portion 10, a signal processing circuit is constructed as an electric circuit including, for example, a thick film hybrid IC circuit that is directly connected to the stress detection sensors 4 to 7 and performs output signal processing thereof. Even with such a configuration, the same effect as that of the first embodiment can be obtained, and when the stress detection sensors 4 to 7 are formed by a thick film circuit, these are constructed as a thick film hybrid IC circuit. Since the baking process can be made common, the manufacturing process becomes simple. In addition, by directly connecting the signal processing circuit for performing the output signal processing of the stress detection sensors 4 to 7 to the upper surface side of the pedestal portion 10, the reliability of connection and the like is improved, downsizing and high density are achieved. In addition, the zero point of the sensor portion and the output sensitivity can be adjusted together, and the reliability of the entire circuit can be improved and the manufacturing adjustment can be facilitated as compared with the conventional one. FIGS. 10 and 11 show the third embodiment of the present invention, and FIGS. 12 and 13 show the fourth embodiment of the present invention, respectively. Different in points. That is, instead of the pedestal portion 2 having an annular shape, the pedestal portions 12 and 13 having a larger area than the pedestal portion 2 are formed integrally with the pressure responsive portion 3 from a ceramic material so that the ceramic diaphragm bodies 14 and 15 are formed. Respectively,
On the upper surface side of the pedestal portions 12 and 13, a signal processing circuit, such as a thick film circuit, which is directly connected to the stress detection sensors 4 to 7 and performs an output signal processing thereof, is attached, as in the second embodiment. . By manufacturing this signal processing circuit with, for example, a hybrid IC circuit as in the second embodiment, the same effects as those in the second embodiment are obtained in accordance with the effects of the first embodiment. In each of the above-mentioned embodiments, the ceramic diaphragm bodies 1, 11, 14 and 15 are not limited to alumina and can be integrally molded and are dense and satisfy mechanical strength. Other materials may be used as long as they can match the characteristics of the sensor, and strain such as a strain gauge manufactured separately instead of the stress detection sensor consisting of the thick film circuit or the thin film circuit of the above-mentioned embodiment may be used. It is also possible to attach a ready-made sensor for converting the signal to an electric signal to a predetermined position of the pressure response unit 3 by adhesion or the like. [0035] As apparent from the foregoing description, according to the ceramic pressure sensor and its manufacturing method of the present invention, was constructed by integrally molding a ceramic diaphragm body pressurization of ceramic material, the firing Therefore, there is no joint between the pedestal part and the pressure response part due to adhesion, and it is possible to improve mechanical strength and dramatically improve sealing. Also, the ceramic diaphragm body is pressed and fired with ceramic material. Since I cut it later to configure it ,
To be able to achieve ultrathin of pressure responsive portion can improve the sensitivity and compactness, yet each of the diaphragm body
By optimizing the dimensions of the parts, the sensitivity is further improved.
In which excellent effects that Ru can be improved and improvement in durability.
【図面の簡単な説明】
【図１】本発明の第１の実施例を示す全体の縦断面図
【図２】全体の上面図
【図３】セラミックダイアフラム本体の製作過程を説明
するための縦断面図
【図４】応力検知センサの電気的接続図
【図５】圧力応動部の応力特性図
【図６】応力検知センサの応力及び電気抵抗特性を示す
図
【図７】応力検知センサの出力信号特性図
【図８】本発明の第２の実施例を示す全体の上面図
【図９】全体の縦断面図
【図１０】本発明の第３の実施例を示す全体の上面図
【図１１】全体の縦断面図
【図１２】本発明の第４の実施例を示す全体の上面図
【図１３】全体の縦断面図
【符号の説明】
図面中、１，１１，１４及び１５はセラミックダイアフ
ラム本体、２，１０，１２及び１３は台座部、３及び９
は圧力応動部、４乃至７は応力検知センサ、８は電気回
路である。BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an overall vertical cross-sectional view showing a first embodiment of the present invention. FIG. 2 is an overall top view. FIG. 3 is a vertical cross-section for explaining a manufacturing process of a ceramic diaphragm body. Surface view [Fig. 4] Electrical connection diagram of stress detection sensor [Fig. 5] Stress characteristic diagram of pressure response part [Fig. 6] Diagram showing stress and electric resistance characteristic of stress detection sensor [Fig. 7] Output of stress detection sensor Signal characteristic diagram [FIG. 8] Overall top view showing the second embodiment of the present invention [FIG. 9] Overall vertical sectional view [FIG. 10] Overall top view showing the third embodiment of the present invention [FIG. 11] Overall vertical cross-sectional view [Fig. 12] Overall top view showing a fourth embodiment of the present invention [Fig. 13] Overall vertical cross-sectional view [Description of symbols] In the drawings, 1, 11, 14 and 15 are Ceramic diaphragm body, 2, 10, 12 and 13 are pedestals, 3 and 9
Is a pressure response unit, 4 to 7 are stress detection sensors, and 8 is an electric circuit.
Claims (1)
より最終形状よりも厚み寸法を増大させた状態で一体成
形した後研削して形成され厚肉な台座部の内側に厚さ約
０．２ｍｍ以下の薄肉な圧力応動部を一体に備えるセラ
ミックダイアフラム本体と、 このセラミックダイアフラム本体の前記圧力応動部に付
設された応力検知センサと、 前記セラミックダイアフラム本体に設けられ前記応力検
知センサに直結されてその出力信号を取り出すための厚
膜回路又は薄膜回路からなる電気回路と を具備し、 前記圧力応動部の半径ａ、圧力応動部の厚さｔ（約０．
２ｍｍ以下）、前記台座部の外周半径ｂ、台座部の厚さ
ｃが、 ｃ≧１０ｔ、ｂ≧ａ＋１０ｔ の寸法関係とされ、且つ台座部の内径部と圧力応動部と
の間が曲率半径Ｒが約０．５ｍｍの円弧面によって連な
っている ことを特徴とするセラミック圧力センサ。２．セラミックダイアフラム本体の素材をセラミック材
料の加圧，焼成により最終形状よりも厚み寸法を増大さ
せた状態で成形した後、前記素材を研削加工することに
より、 厚肉な台座部の内側に厚さ約０．２ｍｍ以下の薄肉な圧
力応動部を一体に備えると共に、圧力応動部の半径ａ、
圧力応動部の厚さｔ（約０．２ｍｍ以下）、前記台座部
の外周半径ｂ、台座部の厚さｃが、 ｃ≧１０ｔ、ｂ≧ａ＋１０ｔ の寸法関係とされ、且つ台座部の内径部と圧力応動部と
の間が曲率半径Ｒが約０．５ｍｍの円弧面によって連な
った形状のセラミックダイアフラム本体を形成し、 この後、セラミックダイアフラム本体の圧力応動部に応
力検知センサを付設すると共に、前記セラミックダイア
フラム本体に、前記応力検知センサに直結されてその出
力信号を取り出すための厚膜回路又は薄膜回路からなる
電気回路を設けるようにしたことを特徴とするセラミッ
ク圧力センサの製造方法。 [Claims] 1. Pressurization of the ceramic material, the final shape having a thickness of about inside the ground and formed by thick-walled base portion after integrally molded in a state of increased thickness than the firing
A ceramic diaphragm body integrally provided with a thin pressure response section of 0.2 mm or less, a stress detection sensor attached to the pressure response section of the ceramic diaphragm body, and a direct connection to the stress detection sensor provided on the ceramic diaphragm body. An electric circuit including a thick film circuit or a thin film circuit for extracting the output signal thereof, the radius a of the pressure responsive portion and the thickness t of the pressure responsive portion (about 0.
2 mm or less) , the outer peripheral radius b of the pedestal portion and the thickness c of the pedestal portion have a dimensional relationship of c ≧ 10t, b ≧ a + 10t , and the inner diameter portion of the pedestal portion and the pressure response portion are
Are connected by an arc surface with a radius of curvature R of about 0.5 mm.
The ceramic pressure sensor is characterized by 2. The material of the ceramic diaphragm body is a ceramic material
Increase the thickness dimension compared to the final shape by pressing and firing the material
After forming in the state of
More, thick-walled base portion thin-walled pressure inside the thickness of less than or equal to about 0.2mm of
The force response part is integrally provided, and the radius a of the pressure response part,
Thickness t of the pressure responsive portion (about 0.2 mm or less), the pedestal portion
The outer peripheral radius b and the thickness c of the pedestal portion are dimensional relations of c ≧ 10t and b ≧ a + 10t , and the inner diameter portion of the pedestal portion and the pressure response portion are
Are connected by an arc surface with a radius of curvature R of about 0.5 mm.
After forming the ceramic diaphragm body with a curved shape, after that, respond to the pressure response part of the ceramic diaphragm body.
A force sensor is attached and the ceramic diamond
The stress detection sensor is directly connected to the flam body and its
Consists of thick film circuit or thin film circuit for extracting force signal
Ceramic circuit characterized by having an electric circuit
Manufacturing method of pressure sensor.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3304048A JPH0663895B2 (en) | 1991-10-23 | 1991-10-23 | Ceramic pressure sensor and manufacturing method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3304048A JPH0663895B2 (en) | 1991-10-23 | 1991-10-23 | Ceramic pressure sensor and manufacturing method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH055664A JPH055664A (en) | 1993-01-14 |
| JPH0663895B2 true JPH0663895B2 (en) | 1994-08-22 |
Family
ID=17928420
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3304048A Expired - Lifetime JPH0663895B2 (en) | 1991-10-23 | 1991-10-23 | Ceramic pressure sensor and manufacturing method thereof |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0663895B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2017058340A (en) * | 2015-09-18 | 2017-03-23 | Smc株式会社 | Pressure sensor and method for manufacturing the same |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4828804B2 (en) * | 2003-06-26 | 2011-11-30 | 京セラ株式会社 | Ceramic diaphragm, manufacturing method thereof, and pressure sensor |
| DE102012111533A1 (en) * | 2012-11-28 | 2014-05-28 | Endress + Hauser Gmbh + Co. Kg | Pressure measuring cell |
| US10175133B2 (en) | 2013-06-07 | 2019-01-08 | Entegris, Inc. | Sensor with protective layer |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| IT1101056B (en) * | 1978-10-12 | 1985-09-28 | Magneti Marelli Spa | PRESSURE METER DEVICE USING A RESISTOR EXTENSIMETER |
| JPS55103441A (en) * | 1979-02-01 | 1980-08-07 | Yokogawa Hokushin Electric Corp | Pressure converter |
| EP0033749B2 (en) * | 1980-02-06 | 1987-11-11 | Hans W. Dipl.-Phys. Keller | Piezoresistive cylindrical-box-like pressure measurement cell |
| JPS58223726A (en) * | 1982-06-23 | 1983-12-26 | Toshiba Corp | Production of diaphragm |
| JPS59186376A (en) * | 1983-04-06 | 1984-10-23 | Hitachi Ltd | Pressure sensor |
-
1991
- 1991-10-23 JP JP3304048A patent/JPH0663895B2/en not_active Expired - Lifetime
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2017058340A (en) * | 2015-09-18 | 2017-03-23 | Smc株式会社 | Pressure sensor and method for manufacturing the same |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH055664A (en) | 1993-01-14 |
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