JP5263641B2 - Pressure-sensitive body, pressure-sensitive element, and pressure detection method using the same - Google Patents

Pressure-sensitive body, pressure-sensitive element, and pressure detection method using the same Download PDF

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JP5263641B2
JP5263641B2 JP2007140598A JP2007140598A JP5263641B2 JP 5263641 B2 JP5263641 B2 JP 5263641B2 JP 2007140598 A JP2007140598 A JP 2007140598A JP 2007140598 A JP2007140598 A JP 2007140598A JP 5263641 B2 JP5263641 B2 JP 5263641B2
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健太郎 猪野
賢治 秋浜
英子 福島
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Hitachi Metals Ltd
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本発明は、感圧素子に関するものであり、特に圧力感度が高い感圧素子に係るものである。   The present invention relates to a pressure sensitive element, and particularly relates to a pressure sensitive element having high pressure sensitivity.

従来から、金属または半導体素子を用いた圧力または荷重検出素子が一般的に使用されており、中でもシリコン単結晶や炭化珪素等からなる半導体圧力検出素子は、金属歪ゲージと比較し、電気抵抗の圧力に対する変化率で表される圧力感度が数桁優れることから圧力を検知する材料、すなわち感圧体として幅広い応用がなされている。しかしながら、従来の半導体圧力検出素子は機械的強度が弱く、高温・高圧下では単体で使用することが出来ないため耐圧容器に組み込んで測定を行っており、検出装置の構成が複雑になるとともにコスト高となる問題があった。   Conventionally, a pressure or load detecting element using a metal or a semiconductor element has been generally used. Among them, a semiconductor pressure detecting element made of silicon single crystal, silicon carbide, or the like has an electric resistance compared to a metal strain gauge. Since the pressure sensitivity expressed by the rate of change with respect to pressure is several orders of magnitude, it is widely used as a material for detecting pressure, that is, a pressure sensitive body. However, conventional semiconductor pressure sensing elements are weak in mechanical strength and cannot be used as a single unit at high temperatures and pressures, so measurements are performed by incorporating them in a pressure vessel, which complicates the configuration of the detection device and reduces costs. There was a problem that would be high.

この問題を解決するために、高温高圧下での使用に耐えうる圧力検出素子の研究が数多くなされており、その一例が特許文献１に開示されている。特許文献１に開示された圧力検出素子は、ＳｉＣを析出させたＳｉ３Ｎ４を主成分とする多結晶セラミックス材料を感圧体として用いた半導体圧力検出素子であり、圧力を加えると電気抵抗が変化するＳｉＣのピエゾ抵抗効果を利用して圧力を検出している。この圧力検出素子はＳｉ３Ｎ４とＣを焼結反応させＳｉＣを析出させることにより製造される。 In order to solve this problem, many researches have been made on pressure detecting elements that can withstand use under high temperature and high pressure, and an example thereof is disclosed in Patent Document 1. The pressure detection element disclosed in Patent Document 1 is a semiconductor pressure detection element using a polycrystalline ceramic material mainly composed of Si 3 N 4 on which SiC is deposited as a pressure sensing element. The pressure is detected using the piezoresistive effect of SiC that changes. This pressure detection element is manufactured by sintering Si 3 N 4 and C to precipitate SiC.

かかる圧力検出素子によれば、高強度のセラミックス材料であるＳｉ３Ｎ４を主成分とするので耐圧容器等に組み込まなくても高い圧力を測定可能であり、かつ、高温でも圧力検出素子が酸化等で性能劣化すること無く測定可能であるという利点がある。しかしながら、この圧力検出素子を発明者が作製し確認したところによれば、この圧力検出素子は、圧力変化に対する電気抵抗変化率すなわち圧力感度が−０.００５％／ＭＰａ程度と低いということ、焼結・加工に手間がかかり高コストになってしまうという問題があった。 According to such a pressure detection element, Si 3 N 4 which is a high-strength ceramic material is a main component, so that a high pressure can be measured without being incorporated in a pressure vessel or the like, and the pressure detection element is oxidized even at a high temperature. There is an advantage that measurement is possible without degrading performance. However, according to the fact that the inventor made and confirmed this pressure detection element, the pressure detection element has a low rate of change in electrical resistance with respect to a pressure change, that is, a pressure sensitivity of about -0.005% / MPa. There was a problem that it took a lot of time for the tying and processing, resulting in high costs.

また、特許文献２には導電性粉末をプラスチック内に導電性経路を形成させた状態で分散させた成形体を用いた荷重検知方法に関する記載がある。この方法ではプラスチック内に分散された導電性粉末の接触状態が圧力によって変化することにより電気抵抗が変化して圧力を検出することができる。また、プラスチック自体が高強度であるため、耐圧容器に組み込まなくても高い圧力を測定することができる。しかしながらこの材料は圧力に対する電気抵抗変化が直線的でないために精密に圧力を検出できないこと、また圧力が加わると塑性変形を起こすため、電気抵抗が元の値に戻らず２回以上の圧力を正確に検出することができないという問題があった。   Patent Document 2 describes a load detection method using a molded body in which conductive powder is dispersed in a state where a conductive path is formed in plastic. In this method, when the contact state of the conductive powder dispersed in the plastic changes according to the pressure, the electric resistance changes, and the pressure can be detected. In addition, since the plastic itself has high strength, a high pressure can be measured without being incorporated in a pressure resistant container. However, this material cannot detect the pressure accurately because the change in electrical resistance with respect to pressure is not linear, and plastic deformation occurs when pressure is applied. Therefore, the electrical resistance does not return to the original value, and the pressure more than 2 times is accurate. There was a problem that it could not be detected.

特開２００４−２０３５５号公報JP 2004-20355 A 特許第３６１３４１６号Japanese Patent No. 3613416

本発明は、上記従来の問題を解決するため発明者が鋭意検討してなされたものであり、優れた圧力感度を有する新しい原理に基づく感圧体を提供することを目的とし、好ましくは２００℃の高温下でも使用可能である感圧体を提供し、さらに好ましくは１００ＭＰa以上の高圧下でも使用可能で信頼性の高い感圧素子を提供する。   The present invention has been made by the inventor's earnest study in order to solve the above-described conventional problems, and aims to provide a pressure-sensitive body based on a new principle having an excellent pressure sensitivity, preferably 200 ° C. A pressure-sensitive element that can be used even at high temperatures is provided, and more preferably, a pressure-sensitive element that can be used even under a high pressure of 100 MPa or more and has high reliability.

以下、本発明について、その実施態様に基づき理解のため図面１を参照しつつ説明する。図１は本発明の感圧体を模式的に示した図、図２は感圧体が電極と受圧体を有する感圧素子の模式図、図３は電極と受圧体が一体構造となった感圧素子の模式図、図４は電極と受圧体の他に、感圧体の外周部に金属又はセラミックス焼結体よりなる外周保持体を有する感圧素子の断面図である。   Hereinafter, the present invention will be described with reference to FIG. 1 for understanding based on the embodiment. FIG. 1 is a diagram schematically showing a pressure-sensitive body of the present invention, FIG. 2 is a schematic diagram of a pressure-sensitive element having a pressure-sensitive body having an electrode and a pressure-receiving body, and FIG. 3 is an integrated structure of the electrode and pressure-receiving body. FIG. 4 is a cross-sectional view of a pressure-sensitive element having an outer periphery holding body made of a metal or a ceramic sintered body on the outer periphery of the pressure-sensitive body in addition to the electrode and the pressure-receiving body.

図面１は本発明の感圧体１を模式的に示した図である。請求項１に記載の発明は、第一の粉体１１中に第二の粉体１２が導電性の経路を形成した状態で分散してなり、その空隙率が２５％以上、５５％以下であることを特徴とした感圧体の材料であって、加圧による前記第一の粉体と第二の粉体および前記第二の粉体同士の接触状態が変化して電気抵抗が変化する特性を有する感圧体である。かかる圧力検出素子によれば、図1（ａ）に示す感圧体に圧力が作用していない又は圧力が低い状態に対し、同図（ｂ）に示す作用する圧力が増加した状態では加圧方向に感圧体が押しつぶされることによって、第一の粉体１１と導電性を有する第二の粉体１２、及び第二の粉体粒子１２同士の接触面積が増加するなど両者の接触状態が変化する。第一の粉体１１同士の接触面積も増加するが、それらが形成する経路の電気抵抗は他と比べて非常に大きいため感圧体の電気抵抗に与える影響は小さく無視し得る。第一の粉体と第二の粉体の各電気抵抗率が大きく異なるときは感圧体の電気抵抗は主に抵抗率の小さい第二の粉体同士の接触状態に依存する。本発明の最も好適な感圧体１は絶縁材料からなる第一の粉体１１と導電性材料からなる第二の粉体１２とから構成される。第一の粉体と第二の粉体の各電気抵抗率に大きな差がないときは感圧体の電気抵抗は主に第一の粉体と第二の粉体との接触状態および第二の粉体同士の接触状態に依存する。また、電気抵抗率が０.００１〜１００Ω・ｍ程度の範囲にある粉体を選択することにより第一の粉体と第二の粉体とを同一の粉体とすることも可能である。この範囲外では感圧素子として評価するには適当な電気抵抗値が得られず不適である。この作用する圧力に応じた接触状態の変化により第一の粉体１１と第二の粉体１２および、第二の粉体１２同士の界面の接触抵抗が変化し、その結果、作用する圧力に応じて感圧体１の電気抵抗が変化する。   FIG. 1 is a view schematically showing a pressure-sensitive body 1 of the present invention. In the invention according to claim 1, the second powder 12 is dispersed in the first powder 11 in a state in which a conductive path is formed, and the porosity is 25% or more and 55% or less. A material for a pressure-sensitive body, wherein the contact state between the first powder, the second powder, and the second powder changes due to pressurization, and the electrical resistance changes. It is a pressure-sensitive body having characteristics. According to such a pressure detection element, pressure is not applied to the pressure sensitive body shown in FIG. 1A or the pressure is low, while the pressure shown in FIG. When the pressure sensitive body is crushed in the direction, the contact area between the first powder 11 and the conductive second powder 12 and the second powder particles 12 is increased. Change. Although the contact area between the first powders 11 also increases, the electrical resistance of the path formed by them is much larger than the others, so the influence on the electrical resistance of the pressure sensitive body is small and can be ignored. When the electrical resistivity of the first powder and that of the second powder are greatly different, the electrical resistance of the pressure sensitive body mainly depends on the contact state between the second powders having low resistivity. The most preferred pressure-sensitive body 1 of the present invention comprises a first powder 11 made of an insulating material and a second powder 12 made of a conductive material. When there is no significant difference in the electrical resistivity between the first powder and the second powder, the electrical resistance of the pressure sensitive body is mainly the contact state between the first powder and the second powder and the second Depends on the contact state between the powders. It is also possible to make the first powder and the second powder the same powder by selecting a powder having an electrical resistivity in the range of about 0.001 to 100 Ω · m. Outside this range, an appropriate electrical resistance value cannot be obtained for evaluation as a pressure sensitive element, which is inappropriate. The contact resistance at the interface between the first powder 11, the second powder 12, and the second powder 12 changes due to the change in the contact state in accordance with the acting pressure. Accordingly, the electrical resistance of the pressure sensitive body 1 changes.

この時、感圧体の空隙率が２５％以上であることにより、空隙率が２５％より小さい緻密な状態と比べて加圧時の体積変化が大きく第一の粉体１１と第二の粉体１２、および第二の粉体１２同士の接触面積変化が大きくなり、電気抵抗変化率の絶対値が０.２％／ＭＰａ以上の優れた圧力感度を有する感圧体を得ることが可能となる。ここで、空隙率が５５％より大きくなると、加圧によって空隙が潰れて感圧体１がより高密度に充填されて感圧体１の密度が高くなり、元の空隙率の状態に戻らなくなってしまい抵抗値が減少したままの状態になり初期抵抗値が変化するため、正確に圧力を検知するのが困難になってしまう。逆に５５％以下の空隙率であれば、減圧後も加圧前と同じ状態に戻るため、２回以上の受圧検知機能を有する感圧体を得ることができる。   At this time, since the porosity of the pressure-sensitive body is 25% or more, the volume change at the time of pressurization is large compared with the dense state where the porosity is smaller than 25%, and the first powder 11 and the second powder. The contact area change between the body 12 and the second powder 12 is increased, and it is possible to obtain a pressure-sensitive body having excellent pressure sensitivity with an absolute value of the electric resistance change rate of 0.2% / MPa or more. Become. Here, when the porosity becomes larger than 55%, the pressure is crushed by pressurization and the pressure-sensitive body 1 is filled with a higher density, and the density of the pressure-sensitive body 1 is increased, and the original porosity is not restored. As a result, the resistance value remains reduced and the initial resistance value changes, making it difficult to accurately detect the pressure. On the other hand, if the porosity is 55% or less, the pressure sensor returns to the same state as before pressurization after decompression, so that a pressure sensitive body having a pressure sensing function of two or more times can be obtained.

このように、上記圧力検出素子では導電性粒子等のピエゾ抵抗効果を利用するのではなく、第一の粉体１１と第二の粉体１２および第二の粉体１２同士の接触界面における接触状態の変化、具体的に言えば接触抵抗の変化を利用して圧力を検出するので、従来のピエゾ抵抗効果を利用する圧力検出素子に比べて加圧時の電気抵抗変化率が大きく、優れた圧力感度を有する感圧体を得ることができる。また、第１の粒子又は第２の粒子を広い範囲から選択することができ、工業生産上有利である。さらに、粉体のまま用いることによって、焼結や加工のプロセスを省略でき低コストで感圧体を製造することができる。   Thus, the pressure detection element does not use the piezoresistance effect of conductive particles or the like, but contacts at the contact interface between the first powder 11, the second powder 12, and the second powder 12. Since the pressure is detected using a change in state, more specifically, a change in contact resistance, the rate of change in electrical resistance during pressurization is larger than that of a conventional pressure detection element that uses the piezoresistance effect, which is superior. A pressure-sensitive body having pressure sensitivity can be obtained. Further, the first particle or the second particle can be selected from a wide range, which is advantageous in industrial production. Further, by using the powder as it is, the sintering and processing processes can be omitted, and the pressure-sensitive body can be produced at low cost.

前記第一の発明において第二の粉体の電気抵抗率は第一の粉体の抵抗率と同じかそれ以下の電気抵抗率であって、第二の粉体の電気抵抗率が１００Ω・ｍ以下であることが望ましい。第二の粉体の電気抵抗率が第一の粉体の電気抵抗率と同じかそれ以下の電気抵抗率であることにより、導電性の経路は第二の粉体が受け持つことで、電気的特性は第二の粉体の特性にのみ依存するため電気抵抗値の制御が容易となり、また、１００Ω・ｍ以下の粉体を選ぶことにより感圧体として使用する場合の電気的な信号処理が簡単である５０〜１００００Ωの抵抗値を具現化することが容易となる。電気抵抗値が５０Ωよりも小さいと、センサにした際に素子に流れる電流が多くなりすぎ発熱量が多く誤差の多いセンサとなってしまう。また、１００００Ωよりも大きいと、電極と感圧体の電気的導通を確保することが困難になり、センサの信号処理が困難になってしまう。   In the first invention, the electrical resistivity of the second powder is equal to or lower than that of the first powder, and the electrical resistivity of the second powder is 100 Ω · m. The following is desirable. Since the electrical resistivity of the second powder is equal to or less than the electrical resistivity of the first powder, the conductive path is handled by the second powder. Since the characteristics depend only on the characteristics of the second powder, it is easy to control the electrical resistance value, and by selecting a powder of 100 Ω · m or less, electrical signal processing when used as a pressure-sensitive body is possible. It becomes easy to embody a simple resistance value of 50 to 10000Ω. If the electric resistance value is smaller than 50Ω, the current flowing through the element becomes excessive when the sensor is used, resulting in a sensor with a large amount of heat generation and a large error. On the other hand, if it is greater than 10000Ω, it is difficult to ensure electrical continuity between the electrode and the pressure-sensitive body, and signal processing of the sensor becomes difficult.

さらに加えて上記感圧体において、前記感圧体の曲げ強度が０．１ＭＰa以上、２０ＭＰａ以下であることが望ましい。前記感圧体の曲げ強度が０．１ＭＰaよりも小さいと機械強度不足で加圧時に感圧体が壊れてしまう。また、前記感圧体の曲げ強度が２０ＭＰａよりも大きいと機械強度が高すぎて加圧時の歪が小さく優れた圧力感度を得ることができない。   In addition, in the pressure sensitive body, it is desirable that the bending strength of the pressure sensitive body is 0.1 MPa or more and 20 MPa or less. If the bending strength of the pressure sensitive body is less than 0.1 MPa, the pressure sensitive body will be broken during pressurization due to insufficient mechanical strength. On the other hand, if the bending strength of the pressure-sensitive body is greater than 20 MPa, the mechanical strength is too high, and the strain at the time of pressurization is small, so that excellent pressure sensitivity cannot be obtained.

さらに加えて前記第一の粉体が窒化珪素、サイアロン、窒化アルミニウム、アルミナ、シリカ、イットリア、ムライト、ジルコニア、マグネシア、コージェライト、アルミニウムチタネート、カーボン、炭化珪素、酸化錫、酸化インジウム、酸化銀、酸化銅、酸化亜鉛、酸化鉄、及びIV、V、VI族の遷移金属元素の炭化物、窒化物、ホウ化物、珪化物、酸化物、及びこれらの物質の二種以上で構成される複合化合物からなる群から選ばれるいずれか一種または二種以上を含む粉体からなり、前記第二の粉体が、カーボン、炭化珪素、酸化錫、酸化インジウム、酸化銀、酸化銅、酸化亜鉛、及びIV、V、VI族の遷移金属元素の炭化物、窒化物、ホウ化物、珪化物、酸化物、及びこれらの物質の二種以上で構成される複合化合物からなる群から選ばれるいずれか一種または二種以上を含む粉体からなることが望ましい。感圧体を構成する粉体を上記の耐熱性に優れた材料の組み合わせから選ぶことにより、２００℃の高温下でも圧力を検知することができる感圧体を得ることができる。   In addition, the first powder is silicon nitride, sialon, aluminum nitride, alumina, silica, yttria, mullite, zirconia, magnesia, cordierite, aluminum titanate, carbon, silicon carbide, tin oxide, indium oxide, silver oxide, From copper oxide, zinc oxide, iron oxide, and carbides, nitrides, borides, silicides, oxides, and complex compounds composed of two or more of these substances, transition metal elements of groups IV, V, and VI The powder comprising any one or two or more selected from the group consisting of, the second powder, carbon, silicon carbide, tin oxide, indium oxide, silver oxide, copper oxide, zinc oxide, and IV, Selected from the group consisting of carbides, nitrides, borides, silicides, oxides of V, VI group transition metal elements, and complex compounds composed of two or more of these substances It is desirable to consist of a powder containing any one kind or two or more kinds. By selecting the powder constituting the pressure sensitive body from the combination of materials having excellent heat resistance, a pressure sensitive body capable of detecting pressure even at a high temperature of 200 ° C. can be obtained.

さらに加えて前記第二の粉体がＣであることが望ましい。Ｃは粉体として軟らかいため圧力を加えた際の感圧体の体積変化が大きく分体同士の接触面積変化が大きくなるため、優れた圧力感度を有する感圧体を得ることができる。   In addition, it is desirable that the second powder is C. Since C is soft as a powder, the volume change of the pressure sensitive body when pressure is applied is large, and the change in the contact area between the divided bodies is large, so that a pressure sensitive body having excellent pressure sensitivity can be obtained.

前記Ｃの添加量は５ｖｏｌ％以上、４０ｖｏｌ％以下であることが望ましい。Ｃの添加量が５ｖｏｌ％よりも少ないと導電性の経路を形成することができず感圧体として使用することができない。また、４０ｖｏｌ％よりも多くなると、電気抵抗値が小さくなりすぎてセンサ化した際の発熱が多く誤差が大きくなるため、感圧体として好ましくない。   The amount of C added is desirably 5 vol% or more and 40 vol% or less. If the amount of C added is less than 5 vol%, a conductive path cannot be formed and the pressure sensitive body cannot be used. On the other hand, if it exceeds 40 vol%, the electrical resistance value becomes too small and heat is generated when the sensor is formed, and the error becomes large.

次に請求項７に記載の発明について図２を参照しつつ説明する。請求項７に記載の発明は、前記感圧体は一対の電極２１を有し、かつセラミックス又は金属素材よりなる受圧体２２に挟まれてなる感圧素子２である。感圧体１に電極２１を設けることで電気抵抗値の測定を容易とし、かつセラミックス又は金属素材よりなる受圧体２２に挟まれることで素子に均一な面圧力を加えることができ、素子への応力集中による破壊を防ぐと共に高い精度での圧力検知が可能となる。   Next, the invention described in claim 7 will be described with reference to FIG. The invention according to claim 7 is the pressure-sensitive element 2 in which the pressure-sensitive body has a pair of electrodes 21 and is sandwiched between pressure-receiving bodies 22 made of ceramics or a metal material. By providing the electrode 21 on the pressure-sensitive body 1, it is possible to easily measure the electric resistance value, and it is possible to apply a uniform surface pressure to the element by being sandwiched between the pressure-receiving body 22 made of ceramics or a metal material. Breakage due to stress concentration can be prevented and pressure detection can be performed with high accuracy.

さらに図３に示したように、前記金属素材よりなる受圧体２２は電極２１としての機能を有することが望ましい。受圧体が電極としての機能も兼ねることで部品の省略が可能となり、安価な感圧素子３を得ることができる。   Further, as shown in FIG. 3, the pressure receiving body 22 made of the metal material preferably has a function as the electrode 21. Since the pressure receiving body also functions as an electrode, parts can be omitted, and an inexpensive pressure sensitive element 3 can be obtained.

図４は電極と受圧体が同一部材からなる受圧体４１のほかに金属又はセラミックス焼結体よりなる外周保持体４２を有する感圧素子４の断面図である。図４に示したように、前記感圧体１は金属素材よりなる受圧体４１のほかに、外周部を保持する金属又はセラミックス焼結体からなる外周保持体４２を有することが望ましい。感圧体１の外周部を金属又はセラミックス焼結体のような高強度部材からなる外周保持体４２で囲うことにより、高圧時に潰れて横に広がろうとする感圧体１を外周保持体４２が横から支持し過度の変形を防ぎ、感圧素子４の強度が感圧体１では無く金属又はセラミックス焼結体製の外周保持体４２の強度に依存するために感圧素子４の機械強度が飛躍的に向上し、信頼性の向上や１００ＭＰa以上の高圧下での圧力検知も可能な感圧素子４を得ることが出来る。また、受圧体４１から電極の機能を切り離して電極を別に用意し、この電極を感圧体１に電気的に接触させて設け、更にこの電極の上に受圧体４１を設ける構成を採用することもできる。   FIG. 4 is a cross-sectional view of the pressure-sensitive element 4 having an outer periphery holding body 42 made of a metal or a ceramic sintered body in addition to the pressure receiving body 41 whose electrode and pressure receiving body are made of the same member. As shown in FIG. 4, it is desirable that the pressure sensitive body 1 has an outer peripheral holding body 42 made of a metal or ceramic sintered body holding the outer peripheral portion in addition to the pressure receiving body 41 made of a metal material. By surrounding the outer periphery of the pressure-sensitive body 1 with an outer periphery holding body 42 made of a high-strength member such as a metal or ceramic sintered body, the pressure-sensitive body 1 that is crushed at high pressure and tries to spread laterally is supported on the outer periphery holding body 42. Is supported from the side to prevent excessive deformation, and the strength of the pressure-sensitive element 4 depends not on the pressure-sensitive body 1 but on the strength of the outer peripheral holding body 42 made of a metal or a ceramic sintered body. Can be improved drastically, and the pressure-sensitive element 4 capable of improving the reliability and detecting the pressure under a high pressure of 100 MPa or more can be obtained. In addition, the electrode function is separated from the pressure receiving body 41, and another electrode is prepared. The electrode is provided in electrical contact with the pressure sensitive body 1, and the pressure receiving body 41 is further provided on the electrode. You can also.

さらに加えて前記外周保持体４２と感圧体１とが接する面には絶縁材４３が介在してなることが望ましい。外周保持体４２と感圧体１とが接する面が電気的に絶縁されることによって、通電経路が受圧体（金属電極）４１→感圧体１→受圧体（金属電極）４１と容易に限定することができ、安定した電気抵抗値の計測が可能となる。   In addition, it is desirable that an insulating material 43 is interposed on the surface where the outer periphery holding body 42 and the pressure sensitive body 1 are in contact. By electrically insulating the surface where the outer periphery holding body 42 and the pressure sensitive body 1 are in contact with each other, the energization path is easily limited to the pressure receiving body (metal electrode) 41 → the pressure sensitive body 1 → the pressure receiving body (metal electrode) 41. This makes it possible to measure a stable electrical resistance value.

さらに加えて前記外周保持体のヤング率が１００ＧＰａ以上であることが望ましい。ヤング率が１００ＧＰa以上の高い材料から外周保持体の材料を選定することにより、より機械強度の高い感圧素子を得ることができ、２００ＭＰａの高い圧力下でも圧力検知可能な感圧素子を得ることができる。   In addition, it is preferable that the Young's modulus of the outer peripheral holder is 100 GPa or more. By selecting the material of the outer peripheral holder from a material having a high Young's modulus of 100 GPa or more, a pressure sensitive element with higher mechanical strength can be obtained, and a pressure sensitive element capable of detecting pressure even under a high pressure of 200 MPa can be obtained. Can do.

さらに加えて前記感圧体には１０ＭＰａ以上の予圧を負荷されていることが望ましい。粉体は印加圧力が高ければ高いほど元の状態に戻ろうとする力が強く、減圧時に短時間で元の状態に戻る性質を有している。そのため、感圧体に１０ＭＰａ以上の圧力を負荷しておくことで粉体同士の接触状態変化に要する時間が短くなり、応答性の速い感圧素子を得ることができる。   In addition, it is desirable that the pressure sensitive body is loaded with a preload of 10 MPa or more. The higher the applied pressure, the stronger the force of returning to the original state, and the powder has the property of returning to the original state in a short time during decompression. Therefore, by applying a pressure of 10 MPa or more to the pressure sensitive body, the time required for changing the contact state between the powders is shortened, and a pressure sensitive element with quick response can be obtained.

さらに加えて前記感圧素子がリング形状であることが望ましい。感圧素子の形状をリング形状とすることで、リング中心の穴にネジなどを通し、台座などに共締めすることで組み付けと同時に圧力負荷装置などを用いることなく、簡素な構造で１０ＭＰａ以上の予圧を付与することができると共に、締め付けトルクによって予圧を制御することができる。   In addition, it is desirable that the pressure sensitive element has a ring shape. By making the shape of the pressure sensitive element into a ring shape, a screw or the like is passed through the hole in the center of the ring, and it is fastened together with a pedestal etc. A preload can be applied and the preload can be controlled by a tightening torque.

請求項１４の発明は、請求項７乃至１３のいずれかに記載の感圧素子に１０ＭＰａ以上の圧力を負荷した状態で圧力を検出することを特徴とする圧力検出方法である。感圧素子に１０ＭＰａ以上の圧力を負荷しておくことで粉体同士の接触状態変化に要する時間が短くなり、応答性の速い感圧素子を得ることができる。   A fourteenth aspect of the present invention is a pressure detection method, wherein the pressure is detected in a state where a pressure of 10 MPa or more is loaded on the pressure sensitive element according to any one of the seventh to thirteenth aspects. By applying a pressure of 10 MPa or more to the pressure sensitive element, the time required for changing the contact state between the powders is shortened, and a pressure sensitive element with quick response can be obtained.

上記説明したように、本発明によれば、第一の粉体と第二の粉体及び第二の粉体同士の接触界面における接触状態の変化、具体的に言えば接触抵抗の変化を利用して圧力を検出し、さらに感圧体の空隙率が２５％以上、５５％以下とすることで加圧時の電気抵抗変化率の絶対値が０.２％／ＭＰａ以上と大きく、優れた圧力感度を有する新規な感圧体を提供することができる。この新規な感圧体は、感圧体を構成する第一の粉体と第二の粉体を耐熱性に優れた材料から選定することにより２００℃の高温下において高い圧力感度を備えた感圧体を提供できる。また、感圧体に電極を設け、金属製の外周保持体で構成することにより、１００ＭＰａ以上の高圧下でも圧力検知可能な感圧素子を提供することができる。   As described above, according to the present invention, the change in the contact state at the contact interface between the first powder, the second powder, and the second powder, specifically, the change in the contact resistance is used. By detecting the pressure and setting the porosity of the pressure sensitive body to 25% or more and 55% or less, the absolute value of the rate of change in electrical resistance during pressurization is as large as 0.2% / MPa or more, which is excellent. A novel pressure-sensitive body having pressure sensitivity can be provided. This new pressure-sensitive body has a high pressure sensitivity at a high temperature of 200 ° C. by selecting the first powder and the second powder constituting the pressure-sensitive body from materials having excellent heat resistance. A pressure body can be provided. Moreover, a pressure-sensitive element capable of detecting pressure even under a high pressure of 100 MPa or more can be provided by providing an electrode on the pressure-sensitive body and configuring the pressure-sensitive body with a metal outer peripheral holding body.

以下、本発明を、その実施例によって具体的に説明する。   Hereinafter, the present invention will be specifically described with reference to examples.

（実施例１）
第一の粉体にＳｉ３Ｎ４を、第二の粉体にＣを用いた例である。感圧体の製造方法について説明する。第一の粉体１１としてＳｉ３Ｎ４（宇部興産社製、型番：Ｅ１０）４４．０ｇ秤量し、第二の粉体１２にＣ（東海カーボン社製、黒鉛化Ｃ、型番：＃３８５５）を６.０ｇ秤量して、エタノール中でボールミル混合を２４時間行った後、混合粉を乾燥して感圧体の材料となる粉末を得た。次に得られた粉末０．２ｇを内径φ７ｍｍの金型に入れ、３００ＭＰaの圧力で成形し感圧体１を得た。感圧体１の製造条件を表１に示した。
［評価方法］
空隙率は感圧体の寸法を測定し体積を算出、得られた値と感圧体の重量で密度を計算し、理論密度と比較して空隙率を算出した。電気抵抗値と電気抵抗変化率（圧力感度）の測定はφ７ｍｍの円筒状感圧体の上下面にφ７ｍｍ、厚さ１ｍｍのＣｕ電極３１を配設し図３に示す感圧素子３を作製した。Ｃｕ電極３１に０−１ＭＰａの圧力を加えながら抵抗計３５４１（日置電機社製、型番：３５４１）を用いて電気抵抗値及び電気抵抗変化率の評価を行った（２５℃、２００℃の２点）。また、所定の圧力を繰り返し１００回加えた後、同様な電気特性が得られるかどうかを確認した。さらに加圧してから抵抗値が一定になるまでの時間を計測し応答性の評価をあわせて行った。３点曲げ試験は、ＪＩＳ:Ｒ１６０１に基づいて行った。ただし、支点間距離は７ｍｍとした。なお、以下の実施例２〜１３及び比較例１〜５でも同様な方法で評価した。
［評価結果］
得られた測定結果を表２に示した。感圧体の電気抵抗値は１２０Ω、空隙率は２５％、曲げ強度１８ＭＰａ、応答速度は０.５秒、圧力に対する抵抗値変化の直線性も良好であり、その電気抵抗変化率は−０.２１％/ＭＰａの値が得られた。また、１００回の圧力負荷後も１回目と同等の電気特性が得られた。 Example 1
In this example, Si 3 N 4 is used for the first powder, and C is used for the second powder. A method for manufacturing the pressure sensitive body will be described. 44.0 g of Si 3 N 4 (manufactured by Ube Industries, model number: E10) is weighed as the first powder 11, and C (graphite C, manufactured by Tokai Carbon Co., model number: # 3855) is used as the second powder 12. 6.0 g was weighed and ball milled in ethanol for 24 hours, and then the mixed powder was dried to obtain a powder that would be a pressure sensitive material. Next, 0.2 g of the obtained powder was put in a metal mold having an inner diameter of 7 mm and molded at a pressure of 300 MPa to obtain a pressure-sensitive body 1. The production conditions of the pressure sensitive body 1 are shown in Table 1.
[Evaluation method]
The porosity was measured by measuring the size of the pressure-sensitive body, calculating the volume, calculating the density based on the obtained value and the weight of the pressure-sensitive body, and comparing the theoretical density with the porosity. The electrical resistance value and the rate of change in electrical resistance (pressure sensitivity) were measured by arranging a Cu electrode 31 having a diameter of 7 mm and a thickness of 1 mm on the upper and lower surfaces of a cylindrical pressure-sensitive body having a diameter of 7 mm to produce a pressure-sensitive element 3 shown in FIG. . The electrical resistance value and the rate of change in electrical resistance were evaluated using a resistance meter 3541 (manufactured by Hioki Electric Co., Ltd., model number: 3541) while applying a pressure of 0 to 1 MPa to the Cu electrode 31 (2 points of 25 ° C. and 200 ° C.). ). Also, after repeatedly applying a predetermined pressure 100 times, it was confirmed whether or not similar electrical characteristics could be obtained. Furthermore, the time from pressurization until the resistance value became constant was measured, and the responsiveness was also evaluated. The three-point bending test was performed based on JIS: R1601. However, the distance between fulcrums was 7 mm. The following Examples 2 to 13 and Comparative Examples 1 to 5 were also evaluated in the same manner.
[Evaluation results]
The obtained measurement results are shown in Table 2. The pressure-sensitive body has an electric resistance value of 120Ω, a porosity of 25%, a bending strength of 18 MPa, a response speed of 0.5 seconds, a good linearity of resistance value change with respect to pressure, and an electric resistance change rate of −0. A value of 21% / MPa was obtained. In addition, electrical characteristics equivalent to the first time were obtained even after 100 pressure loads.

（実施例２）
成形圧３０ＭＰａで感圧体１を作製した以外は実施例１と同様の方法で感圧体を作製、特性評価を行った。感圧体の作製方法を表１に、得られた結果を表２に示した。 (Example 2)
A pressure sensitive material was produced and evaluated by the same method as in Example 1 except that the pressure sensitive material 1 was produced at a molding pressure of 30 MPa. The production method of the pressure-sensitive body is shown in Table 1, and the obtained results are shown in Table 2.

（実施例３）
成形圧を０.１ＭＰａで感圧体１を作製した以外は実施例１と同様の方法で感圧体を作製、特性評価を行った。感圧体の作製方法を表１に、得られた結果を表２に示した。 (Example 3)
A pressure sensitive body was produced in the same manner as in Example 1 except that the pressure sensitive body 1 was produced at a molding pressure of 0.1 MPa, and the characteristics were evaluated. The production method of the pressure-sensitive body is shown in Table 1, and the obtained results are shown in Table 2.

（実施例４）
第一の粉体にエポキシ樹脂を、第二の粉体にＣを用いた例である。第一の粉体１１としてエポキシ樹脂粉末（ジャパンエポキシレジン社製、型番：４００７Ｐ）２５．０ｇ秤量し、第二の粉体１２にＣ（東海カーボン社製、黒鉛化Ｃ、型番：＃３８５５）を２５.０ｇ秤量して、エタノール中でボールミル混合を２４時間行った後、混合粉を乾燥して感圧体の材料となる粉末を得た。次に得られた粉末０．２ｇを内径φ７ｍｍの金型に入れ、３０ＭＰaの圧力で成形し感圧体１を得た。評価方法は実施例１と同様の方法で行った。感圧体の製造条件を表１に、得られた結果を表２に示した。２００℃での電気抵抗値の測定は樹脂が溶融してしまい計測することができなかった。 Example 4
In this example, epoxy resin is used for the first powder and C is used for the second powder. 25.0 g of epoxy resin powder (manufactured by Japan Epoxy Resin Co., Ltd., model number: 4007P) is weighed as the first powder 11, and C (graphite C, manufactured by Tokai Carbon Co., model number: # 3855) is used as the second powder 12. 25.0 g was weighed and subjected to ball mill mixing in ethanol for 24 hours, and then the mixed powder was dried to obtain a powder to be a pressure sensitive material. Next, 0.2 g of the obtained powder was put in a metal mold having an inner diameter of 7 mm and molded at a pressure of 30 MPa to obtain a pressure-sensitive body 1. The evaluation method was the same as in Example 1. The production conditions of the pressure-sensitive body are shown in Table 1, and the obtained results are shown in Table 2. The measurement of the electric resistance value at 200 ° C. could not be measured because the resin melted.

（実施例５）
第一の粉体と第二の粉体にＳｉＣを用いた例である。第一の粉体１１及び第二の粉体１２としてα−ＳｉＣ粉末（屋久島電工社製、型番：ＳＨ−７）５０.０ｇ秤量し、エタノール中でボールミル混合を２４時間行った後、混合粉を乾燥して感圧体の材料となる粉末を得た。次に得られた粉末０．２ｇを内径φ７ｍｍの金型に入れ、３００ＭＰaの圧力で成形し感圧体１を得た。評価方法は実施例１と同様の方法で行った。感圧体の製造条件を表１に、得られた結果を表２に示した。 (Example 5)
In this example, SiC is used for the first powder and the second powder. As the first powder 11 and the second powder 12, α-SiC powder (manufactured by Yakushima Electric Works, model number: SH-7) was weighed 50.0 g, and after ball mill mixing in ethanol for 24 hours, the mixed powder Was dried to obtain a powder as a material of a pressure sensitive body. Next, 0.2 g of the obtained powder was put in a metal mold having an inner diameter of 7 mm and molded at a pressure of 300 MPa to obtain a pressure-sensitive body 1. The evaluation method was the same as in Example 1. The production conditions of the pressure-sensitive body are shown in Table 1, and the obtained results are shown in Table 2.

（実施例６）
第一の粉体にＳｉ３Ｎ４を、第二の粉体にＳｉＣを用いた例である。第一の粉体１１としてＳｉ３Ｎ４（宇部興産社製、型番：Ｅ１０）３０．０ｇ秤量し、第二の粉体１２にα−ＳｉＣ粉末（高純度化学社製、型番：ＳＩＩ０１ＦＡ）２０．０ｇ秤量して、エタノール中でボールミル混合を２４時間行った後、混合粉を乾燥して感圧体の材料となる粉末を得た。次に得られた粉末０．２ｇを内径φ７ｍｍの金型に入れ、３０ＭＰaの圧力で成形し感圧体１を得た。評価方法は実施例１と同様の方法で行った。感圧体の製造条件を表１に、得られた結果を表２に示した。 (Example 6)
In this example, Si 3 N 4 is used for the first powder, and SiC is used for the second powder. 30.0 g of Si 3 N 4 (manufactured by Ube Industries, model number: E10) is weighed as the first powder 11, and α-SiC powder (model number: SII01FA) 20 is used as the second powder 12. 0.0 g was weighed and ball milled in ethanol for 24 hours, and then the mixed powder was dried to obtain a powder that was used as a pressure sensitive material. Next, 0.2 g of the obtained powder was put in a metal mold having an inner diameter of 7 mm and molded at a pressure of 30 MPa to obtain a pressure-sensitive body 1. The evaluation method was the same as in Example 1. The production conditions of the pressure-sensitive body are shown in Table 1, and the obtained results are shown in Table 2.

（実施例７）
第一の粉体にＡｌ２Ｏ３を、第二の粉体にＴｉＮを用いた例である。第一の粉体１１としてＡｌ２Ｏ３（住友化学社製、型番：ＡＫＰ−５０）２５．０ｇ秤量し、第二の粉体１２にＴｉＮ粉末（フルウチカガク社製、型番：ＴｉＣ７２２０６Ａ）２５．０ｇ秤量して、エタノール中でボールミル混合を２４時間行った後、混合粉を乾燥して感圧体の材料となる粉末を得た。次に得られた粉末０．２ｇを内径φ７ｍｍの金型に入れ、３０ＭＰaの圧力で成形し感圧体１を得た。評価方法は実施例１と同様の方法で行った。感圧体の製造条件を表１に、得られた結果を表２に示した。 (Example 7)
In this example, Al 2 O 3 is used for the first powder and TiN is used for the second powder. 25.0 g of Al 2 O 3 (manufactured by Sumitomo Chemical Co., Ltd., model number: AKP-50) is weighed as the first powder 11, and 25.0 g of TiN powder (manufactured by Furuuchikagaku Co., model number: TiC72206A) is used as the second powder 12. After weighing and ball mill mixing in ethanol for 24 hours, the mixed powder was dried to obtain a powder that was used as a pressure-sensitive material. Next, 0.2 g of the obtained powder was put in a metal mold having an inner diameter of 7 mm and molded at a pressure of 30 MPa to obtain a pressure-sensitive body 1. The evaluation method was the same as in Example 1. The production conditions of the pressure-sensitive body are shown in Table 1, and the obtained results are shown in Table 2.

（実施例８）
第一の粉体にＺｒＯ２を、第二の粉体にＣを用いた例である。第一の粉体１１としてＺｒＯ２（東ソー社製、型番：ＴＺ-３ＹＥ）７３．２ｇ秤量し、第二の粉体１２にＣ（東海カーボン社製、黒鉛化Ｃ、型番：＃３８５５）を６.８８ｇ秤量して、エタノール中でボールミル混合を２４時間行った後、混合粉を乾燥して感圧体の材料となる粉末を得た。次に得られた粉末０．２ｇを内径φ７ｍｍの金型に入れ、３０ＭＰaの圧力で成形し感圧体１を得た。評価方法は実施例１と同様の方法で行った。感圧体の製造条件を表１に、得られた結果を表２に示した。 (Example 8)
In this example, ZrO 2 is used for the first powder and C is used for the second powder. 73.2 g of ZrO 2 (manufactured by Tosoh Corporation, model number: TZ-3YE) is weighed as the first powder 11, and C (manufactured by Tokai Carbon Co., graphitized C, model number: # 3855) is used as the second powder 12. 6.88 g was weighed and ball mill mixed in ethanol for 24 hours, and then the mixed powder was dried to obtain a powder to be a pressure sensitive material. Next, 0.2 g of the obtained powder was put in a metal mold having an inner diameter of 7 mm and molded at a pressure of 30 MPa to obtain a pressure-sensitive body 1. The evaluation method was the same as in Example 1. The production conditions of the pressure-sensitive body are shown in Table 1, and the obtained results are shown in Table 2.

（実施例９）
第一の粉体にＡｌ２Ｏ３を、第二の粉体にＣを用いた例である。第一の粉体１１としてＡｌ２Ｏ３（住友化学工業社製、型番：ＡＫＰ−５０）３６．２ｇ秤量し、第二の粉体１２にＣ（東海カーボン社製、黒鉛化Ｃ、型番：＃３８５５）を６.８８ｇ秤量して、エタノール中でボールミル混合を２４時間行った後、混合粉を乾燥して感圧体の材料となる粉末を得た。次に得られた粉末０．２ｇを内径φ７ｍｍの金型に入れ、３０ＭＰaの圧力で成形し感圧体１を得た。評価方法は実施例１と同様の方法で行った。感圧体の製造条件を表１に、得られた結果を表２に示した。 Example 9
In this example, Al 2 O 3 is used for the first powder and C is used for the second powder. As the first powder 11, 36.2 g of Al 2 O 3 (manufactured by Sumitomo Chemical Co., Ltd., model number: AKP-50) is weighed, and C (manufactured by Tokai Carbon Co., graphitized C, model number) is used as the second powder 12. 6.88 g of # 3855) was weighed and ball milled in ethanol for 24 hours, and then the mixed powder was dried to obtain a powder as a pressure-sensitive material. Next, 0.2 g of the obtained powder was put in a metal mold having an inner diameter of 7 mm and molded at a pressure of 30 MPa to obtain a pressure-sensitive body 1. The evaluation method was the same as in Example 1. The production conditions of the pressure-sensitive body are shown in Table 1, and the obtained results are shown in Table 2.

（実施例１０）
第一の粉体にＳｉＯ２を、第二の粉体にＣを用いた例である。第一の粉体１１としてＳｉＯ２（デンカ工業社製、型番：ＦＳ−３０）３５．０ｇ秤量し、第二の粉体１２にＣ（東海カーボン社製、黒鉛化Ｃ、型番：＃３８５５）を１５.０ｇ秤量して、エタノール中でボールミル混合を２４時間行った後、混合粉を乾燥して感圧体材料となる粉末を得た。次に得られた粉末０．２ｇを内径φ７ｍｍの金型に入れ、３０ＭＰaの圧力で成形し感圧体１を得た。評価方法は実施例１と同様の方法で行った。感圧体の製造条件を表１に、得られた結果を表２に示した。 (Example 10)
In this example, SiO2 is used for the first powder and C is used for the second powder. As the first powder 11, 35.0 g of SiO 2 (manufactured by Denka Kogyo Co., model number: FS-30) is weighed, and C (made by Tokai Carbon Co., graphitized C, model number: # 3855) is used as the second powder 12. After weighing 15.0 g and performing ball mill mixing in ethanol for 24 hours, the mixed powder was dried to obtain a pressure-sensitive material. Next, 0.2 g of the obtained powder was put in a metal mold having an inner diameter of 7 mm and molded at a pressure of 30 MPa to obtain a pressure-sensitive body 1. The evaluation method was the same as in Example 1. The production conditions of the pressure-sensitive body are shown in Table 1, and the obtained results are shown in Table 2.

（実施例１１）
第一の粉体にＳｉ３Ｎ４を、第二の粉体に空洞化Ｃ（ケッチェンブラック（ＫＢ））を用いた例である。第一の粉体１１としてＳｉ３Ｎ４（宇部興産社製、型番：Ｅ１０）４８．０ｇ秤量し、第二の粉体１２にα−ＳｉＣ粉末（ライオン社製、型番：ＥＣ３００Ｊ）２．０ｇ秤量して、エタノール中でボールミル混合を２４時間行った後、混合粉を乾燥して感圧体の材料となる粉末を得た。次に得られた粉末０．２ｇを内径φ７ｍｍの金型に入れ、３０ＭＰaの圧力で成形し感圧体１を得た。評価方法は実施例１と同様の方法で行った。感圧体の製造条件を表１に、得られた結果を表２に示した。 (Example 11)
In this example, Si 3 N 4 is used for the first powder, and Cavity C (Ketjen Black (KB)) is used for the second powder. 48.0 g of Si 3 N 4 (manufactured by Ube Industries, model number: E10) is weighed as the first powder 11, and 2.0 g of α-SiC powder (manufactured by Lion Corporation, model number: EC300J) is weighed as the second powder 12. After weighing and ball mill mixing in ethanol for 24 hours, the mixed powder was dried to obtain a powder that was used as a pressure-sensitive material. Next, 0.2 g of the obtained powder was put in a metal mold having an inner diameter of 7 mm and molded at a pressure of 30 MPa to obtain a pressure-sensitive body 1. The evaluation method was the same as in Example 1. The production conditions of the pressure-sensitive body are shown in Table 1, and the obtained results are shown in Table 2.

実施例１１〜１３は第一の粉体にＳｉ３Ｎ４を、第二の粉体にＣを用いた例であり、Ｃの含有量がそれぞれ１２、２０、３９ｖｏｌ％と異なる以外は実施例２と同様の方法で感圧体を作製、特性評価を行った例である。
（実施例１２）
第一の粉体１１としてＳｉ３Ｎ４（宇部興産社製、型番：Ｅ１０）４５．５ｇ秤量し、第二の粉体１２にＣ（東海カーボン社製黒鉛化Ｃ、型番：＃３８５５）４．５ｇ秤量して、エタノール中でボールミル混合を２４時間行った後、混合粉を乾燥して感圧体の材料となる粉末を得た。それ以外は実施例２と同様の方法で感圧体を作製、特性評価行った。感圧体の製造条件を表１に、得られた結果を表２に示した。 Examples 11 to 13 are examples in which Si 3 N 4 was used as the first powder and C was used as the second powder, except that the C content was different from 12, 20, and 39 vol%, respectively. This is an example in which a pressure-sensitive body was produced by the same method as in No. 2 and the characteristics were evaluated.
(Example 12)
45.5 g of Si 3 N 4 (manufactured by Ube Industries, model number: E10) is weighed as the first powder 11, and C (graphitized C, model number: # 3855) 4 by Tokai Carbon Co., Ltd. is used as the second powder 12. 0.5 g was weighed and ball milled in ethanol for 24 hours, and then the mixed powder was dried to obtain a powder that was used as a pressure sensitive material. Other than that, a pressure-sensitive body was produced and evaluated by the same method as in Example 2. The production conditions of the pressure-sensitive body are shown in Table 1, and the obtained results are shown in Table 2.

（実施例１３）
第一の粉体１１としてＳｉ３Ｎ４（宇部興産社製、型番：Ｅ１０）４２．８ｇ秤量し、第二の粉体１２にＣ（東海カーボン社製黒鉛化Ｃ、型番：＃３８５５）７．２ｇ秤量して、エタノール中でボールミル混合を２４時間行った後、混合粉を乾燥して感圧体の材料となる粉末を得た。それ以外は実施例２と同様の方法で感圧体を作製、特性評価行った。感圧体の製造条件を表１に、得られた結果を表２に示した。 (Example 13)
42.8 g of Si 3 N 4 (manufactured by Ube Industries, model number: E10) is weighed as the first powder 11, and C (graphitized C, model number: # 3855) 7 by Tokai Carbon Co., Ltd. is used as the second powder 12. .2 g was weighed and ball mill mixed in ethanol for 24 hours, and then the mixed powder was dried to obtain a powder that was used as a pressure sensitive material. Other than that, a pressure-sensitive body was produced and evaluated by the same method as in Example 2. The production conditions of the pressure-sensitive body are shown in Table 1, and the obtained results are shown in Table 2.

（実施例１４）
第一の粉体１１としてＳｉ３Ｎ４（宇部興産社製、型番：Ｅ１０）３５．０ｇ秤量し、第二の粉体１２にＣ（東海カーボン社製黒鉛化Ｃ、型番：＃３８５５）１５．０ｇ秤量して、エタノール中でボールミル混合を２４時間行った後、混合粉を乾燥して感圧体の材料となる粉末を得た。それ以外は実施例２と同様の方法で感圧体を作製、特性評価行った。感圧体の製造条件を表１に、得られた結果を表２に示した。 (Example 14)
35.0 g of Si 3 N 4 (manufactured by Ube Industries, model number: E10) is weighed as the first powder 11, and C (graphitized C, model number: # 3855) 15 from the second powder 12 is measured. 0.0 g was weighed and ball milled in ethanol for 24 hours, and then the mixed powder was dried to obtain a powder that was used as a pressure sensitive material. Other than that, a pressure-sensitive body was produced and evaluated by the same method as in Example 2. The production conditions of the pressure-sensitive body are shown in Table 1, and the obtained results are shown in Table 2.

（実施例１５）
受圧体２２と電極２１を別に設けた例である。それ以外の感圧素子の作製方法、特性評価方法は実施例２と同様の方法で行った。感圧体の製造条件を表１に、得られた結果を表２に示した。 (Example 15)
In this example, the pressure receiving body 22 and the electrode 21 are provided separately. The other methods for producing the pressure sensitive element and the method for evaluating the characteristics were performed in the same manner as in Example 2. The production conditions of the pressure-sensitive body are shown in Table 1, and the obtained results are shown in Table 2.

比較例１及び２は実施例１と同様の粉末を用い、成形圧をそれぞれ７００、０.０１ＭＰａと変えた以外は実施例１と同様の方法で感圧体を作製した例である。また比較例３、４はＣの含有量が４．８、４２ｖｏｌ％である以外は実施例２と同様の方法で感圧体を作製した例である。また、実施例５は第二の粉末に抵抗率の高いＳｉ粉末を用いた例である。   Comparative Examples 1 and 2 are examples in which a pressure-sensitive body was produced in the same manner as in Example 1 except that the same powder as in Example 1 was used and the molding pressure was changed to 700 and 0.01 MPa, respectively. Comparative Examples 3 and 4 are examples in which a pressure-sensitive body was produced in the same manner as in Example 2 except that the C content was 4.8 and 42 vol%. Moreover, Example 5 is an example using Si powder with high resistivity for the second powder.

（比較例１）
成形圧を７００ＭＰａで感圧体１を作製した以外は実施例１と同様の方法で感圧体を作製、特性評価を行った。感圧体の作製方法を表１に、得られた結果を表２に示した。空隙率が２２％と低く、曲げ強度が２３ＭＰａと高いために電気抵抗変化率が−０．０９％／ＭＰａと低い値となった。 (Comparative Example 1)
A pressure sensitive material was produced and evaluated by the same method as in Example 1 except that the pressure sensitive material 1 was produced at a molding pressure of 700 MPa. The production method of the pressure-sensitive body is shown in Table 1, and the obtained results are shown in Table 2. Since the porosity was as low as 22% and the bending strength was as high as 23 MPa, the rate of change in electrical resistance was as low as -0.09% / MPa.

（比較例２）
成形圧を０．０１ＭＰａで感圧体１を作製した以外は実施例１と同様の方法で感圧体を作製、特性評価を行った。感圧体の作製方法を表１に、得られた結果を表２に示した。空隙率が５９％と高く、曲げ強度が０．０８ＭＰａと低く機械強度が低いために、電気抵抗変化率測定で１ＭＰaの圧力を加えた際に感圧体が破損してしまい特性評価ができなかった。 (Comparative Example 2)
A pressure-sensitive body was produced and evaluated by the same method as in Example 1 except that the pressure-sensitive body 1 was produced at a molding pressure of 0.01 MPa. The production method of the pressure-sensitive body is shown in Table 1, and the obtained results are shown in Table 2. Since the porosity is as high as 59%, the bending strength is as low as 0.08 MPa, and the mechanical strength is low, the pressure sensitive body is damaged when a pressure of 1 MPa is applied in the measurement of the electric resistance change rate, and the characteristics cannot be evaluated. It was.

（比較例３）
Ｃの含有量が４．８ｖｏｌ％である以外は実施例２と同様の方法で感圧体を作製、特性評価を行った。感圧体の作製方法を表１に、得られた結果を表２に示した。Ｃ含有量が４．８ｖｏｌ％と低いため、導電性の経路を形成することができず、電気抵抗値が高くて特性評価ができなかった。 (Comparative Example 3)
A pressure-sensitive body was produced and evaluated by the same method as in Example 2 except that the C content was 4.8 vol%. The production method of the pressure-sensitive body is shown in Table 1, and the obtained results are shown in Table 2. Since the C content was as low as 4.8 vol%, a conductive path could not be formed, and the electrical resistance value was high, making it impossible to evaluate the characteristics.

（比較例４）
Ｃの含有量が４２ｖｏｌ％である以外は実施例２と同様の方法で感圧体を作製、特性評価を行った。感圧体の作製方法を表１に、得られた結果を表２に示した。Ｃ含有量が４２ｖｏｌ％と高すぎるため、電気抵抗値が２Ωと小さすぎ、感圧素子としては使用できなかった。 (Comparative Example 4)
A pressure-sensitive body was prepared and evaluated for properties in the same manner as in Example 2 except that the C content was 42 vol%. The production method of the pressure-sensitive body is shown in Table 1, and the obtained results are shown in Table 2. Since the C content was too high at 42 vol%, the electric resistance value was too small at 2Ω and could not be used as a pressure sensitive element.

（比較例５）
第一の粉体１１としてＳｉ３Ｎ４（宇部興産社製、型番：Ｅ１０）３０．０ｇ秤量し、第二の粉体１２にＳｉ（住友チタニウム社製、高純度Ｓｉ粉末）３０．０ｇ秤量して、エタノール中でボールミル混合を２４時間行った後、混合粉を乾燥して感圧体の材料となる粉末を得た。それ以外は実施例２と同様の方法で感圧体を作製、特性評価行った。感圧体の製造条件を表１に、得られた結果を表２に示した。電気抵抗値が２３０００Ωと高すぎるため金属電極を押し付けただけでは電気抵抗値が安定せず、特性の評価ができなかった。 (Comparative Example 5)
30.0 g of Si 3 N 4 (manufactured by Ube Industries, model number: E10) is weighed as the first powder 11, and 30.0 g of Si (manufactured by Sumitomo Titanium, high-purity Si powder) is weighed as the second powder 12. Then, after ball mill mixing in ethanol for 24 hours, the mixed powder was dried to obtain a powder that would be a pressure sensitive material. Other than that, a pressure-sensitive body was produced and evaluated by the same method as in Example 2. The production conditions of the pressure-sensitive body are shown in Table 1, and the obtained results are shown in Table 2. Since the electric resistance value was too high at 23000Ω, the electric resistance value was not stabilized only by pressing the metal electrode, and the characteristics could not be evaluated.

Figure 0005263641
Figure 0005263641

Figure 0005263641
Figure 0005263641

実施例１５〜２４は電極や受圧体以外に図４に示す外周保持体４２を用いた感圧素子４の例である。粉末は実施例２の粉末を用いて感圧素子を作製し、特性評価は予圧として１０〜１００ＭＰａの圧力を加えてから、さらに２００ＭＰａの高い圧力をかけて電気抵抗変化率を測定した。   Examples 15-24 are examples of the pressure sensitive element 4 using the outer periphery holding body 42 shown in FIG. 4 other than an electrode and a pressure receiving body. As the powder, a pressure-sensitive element was prepared using the powder of Example 2, and the electrical resistance change rate was measured by applying a pressure of 10 to 100 MPa as a preload and further applying a high pressure of 200 MPa.

（実施例１６）
実施例２と同様の方法で感圧体１を得た後、Ｓｉ３Ｎ４焼結体製（日本タングステン社製、型番：ＮＰＮ−３）外径φ２０ｍｍ、内径φ７．１ｍｍ、高さ２０ｍｍの外周保持体４２の中に感圧体１を入れ、外径７．０ｍｍ、長さ１０ｍｍのＳＵＳ３０４製の電極４１を感圧体１の上下に配設して挟み込み、感圧素子４を得た。得られた感圧素子４に１０ＭＰａの予圧を加え、そこから２００ＭＰａの圧力を加えて特性評価を行った。得られた結果を表３に示した。応答速度も０．１秒以下と速く、２００ＭＰａの高圧でも感圧素子が破損することは無かった。 (Example 16)
After obtaining the pressure sensitive body 1 by the same method as in Example 2, the Si 3 N 4 sintered body (manufactured by Nippon Tungsten Co., Ltd., model number: NPN-3) having an outer diameter of 20 mm, an inner diameter of 7.1 mm, and a height of 20 mm. The pressure-sensitive body 1 was placed in the outer periphery holding body 42, and electrodes 41 made of SUS304 having an outer diameter of 7.0 mm and a length of 10 mm were disposed between the upper and lower sides of the pressure-sensitive body 1 to obtain the pressure-sensitive element 4. . A preload of 10 MPa was applied to the pressure-sensitive element 4 obtained, and a pressure of 200 MPa was applied therefrom, and the characteristics were evaluated. The obtained results are shown in Table 3. The response speed was as fast as 0.1 seconds or less, and the pressure sensitive element was not damaged even at a high pressure of 200 MPa.

（実施例１７）
実施例２と同様の方法で感圧体１を得た後、アルミ製の外径φ２０ｍｍ、内径φ７．２ｍｍ、高さ２０ｍｍの外周保持体４２の内周面に絶縁材４３となるカプトンフィルム（東レデュポン社製、型番：Ｈタイプ）を貼り、その後、感圧体１を入れて外径７．０ｍｍ、長さ１０ｍｍのＳＵＳ３０４製の電極４１を感圧体１上下に配設して挟み込み、感圧素子４を得た。得られた感圧素子４に１０ＭＰａの予圧を加え、そこから２００ＭＰａの圧力を加えて特性評価を行った。得られた結果を表３に示した。１２０ＭＰａまでは電気抵抗評価ができたものの、それ以上の圧力を加えると外周保持体のアルミが変形してしまい、特性評価ができなくなった。そのため表3に示した電気抵抗変化率は１２０ＭＰａまでの抵抗値から算出した値である。 (Example 17)
After obtaining the pressure-sensitive body 1 by the same method as in Example 2, a Kapton film (insulating material 43 on the inner peripheral surface of the outer peripheral holding body 42 having an outer diameter of 20 mm, an inner diameter of 7.2 mm, and a height of 20 mm made of aluminum ( Toray DuPont, Model No .: H type) is attached, and then the pressure sensitive body 1 is put in, and an electrode 41 made of SUS304 having an outer diameter of 7.0 mm and a length of 10 mm is disposed on and under the pressure sensitive body 1. A pressure sensitive element 4 was obtained. A preload of 10 MPa was applied to the pressure-sensitive element 4 obtained, and a pressure of 200 MPa was applied therefrom, and the characteristics were evaluated. The obtained results are shown in Table 3. Although the electrical resistance could be evaluated up to 120 MPa, when a pressure higher than that was applied, the aluminum of the outer periphery holding body was deformed, and the characteristics could not be evaluated. Therefore, the electrical resistance change rate shown in Table 3 is a value calculated from a resistance value up to 120 MPa.

（実施例１８）
外周保持体４２にチタンを用いた以外は実施例１６と同様の方法で感圧素子を作製、特性評価を行った。得られた結果を表３に示した。２００ＭＰａの高圧が加わっても感圧素子が壊れることなく特性評価ができた。 (Example 18)
A pressure-sensitive element was produced in the same manner as in Example 16 except that titanium was used for the outer periphery holding body 42, and the characteristics were evaluated. The obtained results are shown in Table 3. Even when a high pressure of 200 MPa was applied, the characteristics could be evaluated without breaking the pressure sensitive element.

（実施例１９）
外周保持体４２に銅を用いた以外は実施例１６と同様の方法で感圧素子を作製、特性評価を行った。得られた結果を表３に示した。２００ＭＰａの高圧が加わっても感圧素子が壊れることなく特性評価ができた。 (Example 19)
A pressure-sensitive element was produced in the same manner as in Example 16 except that copper was used for the outer periphery holding body 42, and the characteristics were evaluated. The obtained results are shown in Table 3. Even when a high pressure of 200 MPa was applied, the characteristics could be evaluated without breaking the pressure sensitive element.

（実施例２０）
外周保持体４２にＳＵＳ３０４を用いた以外は実施例１６と同様の方法で感圧素子を作製、特性評価を行った。得られた結果を表３に示した。２００ＭＰａの高圧が加わっても感圧素子が壊れることなく特性評価ができた。 (Example 20)
A pressure-sensitive element was produced in the same manner as in Example 16 except that SUS304 was used for the outer peripheral holder 42, and the characteristics were evaluated. The obtained results are shown in Table 3. Even when a high pressure of 200 MPa was applied, the characteristics could be evaluated without breaking the pressure sensitive element.

（実施例２１）
予圧を５０ＭＰａに変えた以外は実施例１９と同様の方法で感圧素子を作製、特性評価を行った。得られた結果を表３に示した。２００ＭＰａの高圧が加わっても感圧素子が壊れることなく特性評価ができた。 (Example 21)
A pressure-sensitive element was produced in the same manner as in Example 19 except that the preload was changed to 50 MPa, and the characteristics were evaluated. The obtained results are shown in Table 3. Even when a high pressure of 200 MPa was applied, the characteristics could be evaluated without breaking the pressure sensitive element.

（実施例２２）
予圧を１００ＭＰａに変えた以外は実施例１９と同様の方法で感圧素子を作製、特性評価を行った。得られた結果を表３に示した。２００ＭＰａの高圧が加わっても感圧素子が壊れることなく特性評価ができた。 (Example 22)
A pressure-sensitive element was produced in the same manner as in Example 19 except that the preload was changed to 100 MPa, and the characteristics were evaluated. The obtained results are shown in Table 3. Even when a high pressure of 200 MPa was applied, the characteristics could be evaluated without breaking the pressure sensitive element.

（実施例２３）
実施例２１と同様の方法で感圧素子４を作製した後、予圧を１００ＭＰａ加えた状態で電極４１と外周保持体４２を溶接して感圧素子を作製した。その後２００ＭＰａの圧力を加えながら電気抵抗変化率を測定し、特性評価を行った。得られた結果を表３に示した。２００ＭＰａの高圧が加わっても感圧素子が壊れることなく特性評価ができた。 (Example 23)
After the pressure-sensitive element 4 was produced by the same method as in Example 21, the electrode 41 and the outer periphery holding body 42 were welded with a preload applied at 100 MPa to produce a pressure-sensitive element. Thereafter, the rate of change in electrical resistance was measured while applying a pressure of 200 MPa, and the characteristics were evaluated. The obtained results are shown in Table 3. Even when a high pressure of 200 MPa was applied, the characteristics could be evaluated without breaking the pressure sensitive element.

実施例２３、２４はリング形状の感圧素子を用いる例である。
（実施例２４）
まずリング形状外周保持体４２の製造方法について説明する。ＳＵＳ３０４製の外径φ２０ｍｍ、内径φ１８．２ｍｍ、高さ２０ｍｍ外周保持体となる外側リングの内側に、ＳＵＳ３０４製の外径φ１５.６ｍｍｍ、内径φ１４.０ｍｍ、高さ２０ｍｍの内側リングを組み合わせ、その間に出来たスペースに、電極４１となるＳＵＳ３０４製の外径φ１８．０ｍｍ、内径１５.８ｍｍ、高さ５.０ｍｍのリングをはめ込んでリング形状の外周保持体４２を作製した。なお、この感圧体と接する外周保持体リングの内周面と外周面には絶縁材４３となるカプトンフィルムが貼られている。その後、実施例２と同様の方法で作製した感圧粉末を０.２ｇ充填し、３０ＭＰａの圧力を加えて成形した。次に電極４１となるＳＵＳ３０４製の外径φ１８．０ｍｍ、内径１５.８ｍｍ、高さ１５.０ｍｍのリングをはめ込んで感圧素子４を得た。その後、Ｍ１４のＳＵＳネジをリング形状の感圧素子の中心部に通し、５０ＭＰａの予圧が加わるように１５Ｎ・ｍのトルクでＳＵＳ３０４製の台座に締め付けた後、ネジ部に２００MPaの圧力を加えて電気抵抗変化率の特性評価を行った。得られた結果を表３に示した。 Examples 23 and 24 are examples using ring-shaped pressure sensitive elements.
(Example 24)
First, a method for manufacturing the ring-shaped outer periphery holding body 42 will be described. SUS304 outer diameter φ20mm, inner diameter φ18.2mm, height 20mm Inside the outer ring that will be the outer periphery holding body, SUS304 outer diameter φ15.6mmm, inner diameter φ14.0mm, height 20mm in combination, A ring-shaped outer periphery holding body 42 was manufactured by fitting a ring made of SUS304 having an outer diameter of 18.0 mm, an inner diameter of 15.8 mm, and a height of 5.0 mm to be the electrode 41 into the space formed. Note that a Kapton film serving as the insulating material 43 is attached to the inner peripheral surface and the outer peripheral surface of the outer peripheral holder ring in contact with the pressure sensitive body. Thereafter, 0.2 g of pressure-sensitive powder produced by the same method as in Example 2 was filled and molded by applying a pressure of 30 MPa. Next, a pressure sensitive element 4 was obtained by fitting a ring made of SUS304 having an outer diameter of 18.0 mm, an inner diameter of 15.8 mm, and a height of 15.0 mm to be the electrode 41. After that, an M14 SUS screw was passed through the center of the ring-shaped pressure-sensitive element, tightened to a SUS304 base with a torque of 15 N · m so that a preload of 50 MPa was applied, and then a pressure of 200 MPa was applied to the screw part. The characteristics of the electric resistance change rate were evaluated. The obtained results are shown in Table 3.

（実施例２５）
実施例２４はネジの締め付けトルクを３０Ｎ・ｍとし、予圧を１００ＭＰａとした以外は実施例２３と同様の方法で感圧素子４を作製、特性評価を行った。得られた結果を表３に示した。 (Example 25)
In Example 24, the pressure-sensitive element 4 was produced in the same manner as in Example 23 except that the screw tightening torque was 30 N · m and the preload was 100 MPa, and the characteristics were evaluated. The obtained results are shown in Table 3.

Figure 0005263641
Figure 0005263641

本発明の実施例１〜３及び比較例１、２から、感圧体の空隙率２５〜５５％の範囲であって、第二の粉体同士の接触抵抗を利用することで電気抵抗変化率の絶対値が０.２％／ＭＰａ以上の優れた圧力感度を持った感圧体が得られること、及び曲げ強度は０．１〜２０ＭＰaの範囲でないと感圧体が壊れてしまったり、０．２％／ＭＰa以上の高い圧力感度が得られないことを示した。実施例１〜３及び５〜２４において、耐熱性を有する粉体から感圧体の材料を選定することにより、２００℃の高温でも圧力の検知が可能であることを示した。また、実施例１〜１４と、比較例５から、第二の粉体の電気抵抗率は１００Ω・ｍ以下でないと、電気抵抗の測定が困難になることを示した。また、実施例１〜４、及び実施例８〜１４から、第二の粉体がＣであると特に高い圧力感度を有する感圧体が得られることを示した。また、実施例９〜１４及び比較例３、４から第二の粉体がＣであるときのＣ含有量は５〜４０ｖｏｌ％が好ましいことを示した。また、実施例１５〜２４では感圧体に金属やセラミックス焼結体からなる外周部保持体を配設した感圧素子とすることで１００ＭＰaの高圧でも圧力を検知出来ること、また外周部保持体のヤング率は１００ＧＰa以上が望ましいことを示した。また、実施例１５〜２４で１０MPa以上の予圧を加えておくことで、０．１秒以下の速い応答性を有する感圧素子が得られることを示した。また、実施例２３、２４からは感圧素子をリング形状とすることで圧力負荷装置などを用いることなく簡素な構造で予圧を加えられること示した。実施例２〜２３においても圧力に対する抵抗値変化の直線性は良好であった。   From Examples 1 to 3 and Comparative Examples 1 and 2 of the present invention, the porosity of the pressure sensitive body is in the range of 25 to 55%, and the electrical resistance change rate is obtained by utilizing the contact resistance between the second powders. A pressure sensitive body having an excellent pressure sensitivity with an absolute value of 0.2% / MPa or more is obtained, and if the bending strength is not within the range of 0.1 to 20 MPa, the pressure sensitive body may be broken, It was shown that high pressure sensitivity of 2% / MPa or more could not be obtained. In Examples 1 to 3 and 5 to 24, it was shown that pressure can be detected even at a high temperature of 200 ° C. by selecting a pressure-sensitive material from heat-resistant powder. Moreover, from Examples 1 to 14 and Comparative Example 5, it was shown that the measurement of electrical resistance becomes difficult unless the electrical resistivity of the second powder is 100 Ω · m or less. Moreover, it was shown from Examples 1-4 and Examples 8-14 that a pressure-sensitive body having particularly high pressure sensitivity can be obtained when the second powder is C. Moreover, when the second powder was C from Examples 9 to 14 and Comparative Examples 3 and 4, the C content was preferably 5 to 40 vol%. Further, in Examples 15 to 24, the pressure can be detected even at a high pressure of 100 MPa by using a pressure-sensitive element in which a pressure-sensitive body is provided with an outer peripheral holding body made of a metal or a ceramic sintered body, and the outer peripheral holding body. It was shown that the Young's modulus of 100 GPa or more is desirable. Moreover, it was shown that a pressure sensitive element having a quick response of 0.1 seconds or less can be obtained by applying a preload of 10 MPa or more in Examples 15 to 24. In addition, from Examples 23 and 24, it was shown that the preload can be applied with a simple structure without using a pressure load device or the like by making the pressure sensitive element into a ring shape. Also in Examples 2 to 23, the linearity of the resistance value change with respect to the pressure was good.

本発明の圧力センサ材料は、圧力に対する電気抵抗率の変化率が大きく、構成を変えれば高温・高圧下でも測定可能で、機械強度が高く耐久性・信頼性に優れるという特徴を有している。そのため、自動車のエンジン内の圧力計測（筒内圧力センサ）、ディーゼルエンジンのインジェクターに燃料を供給するコモンレールの圧力計測に適用可能である。   The pressure sensor material of the present invention has a large rate of change in electrical resistivity with respect to pressure, and can be measured even at high temperature and high pressure if the configuration is changed, and has a feature that mechanical strength is high and durability and reliability are excellent. . Therefore, it is applicable to pressure measurement in a car engine (cylinder pressure sensor) and pressure measurement of a common rail that supplies fuel to an injector of a diesel engine.

本発明の感圧体を模式的に示した図である。It is the figure which showed the pressure sensitive body of this invention typically. 本発明の感圧体に電極と受圧体を有する感圧素子の模式図である。It is a schematic diagram of the pressure sensitive element which has an electrode and a pressure receiving body in the pressure sensitive body of this invention. 本発明の電極と受圧体が一体構造となった感圧素子の模式図である。It is a schematic diagram of a pressure sensitive element in which an electrode and a pressure receiving body of the present invention are integrated. 本発明の感圧体外周部に金属又はセラミックス焼結体よりなる外周保持体を有する感圧体の断面図である。It is sectional drawing of a pressure sensitive body which has the outer periphery holding body which consists of a metal or a ceramic sintered compact in the pressure sensitive body outer peripheral part of this invention.

符号の説明Explanation of symbols

１：感圧体
２，３，４：感圧素子
１１：第一の粉体
１２：第二の粉体
２１：電極
２２：受圧体
３１，４１：電極兼受圧体
４２：外周保持体
４３：絶縁材
1: Pressure-sensitive body 2, 3, 4: Pressure-sensitive element 11: First powder 12: Second powder 21: Electrode 22: Pressure-receiving body 31, 41: Electrode / pressure-receiving body 42: Outer peripheral holding body 43: Insulating material

Claims (11)

Ｓｉ ３ Ｎ ４ 、エポキシ樹脂、ＳｉＣ、Ａｌ ２ Ｏ ３ 、ＺｒＯ ２ 及びＳｉＯ ２ からなる群から選ばれるいずれか一種を含む粉体からなる第一の粉体とＣ、ＳｉＣ、ＴｉＮ及び空洞化Ｃからなる群から選ばれるいずれか一種を含む粉体からなる第二の粉体とを有する混合粉を圧力で成形し焼結することなく得る前記第一の粉体中に前記第二の粉体が導電性の経路を形成した状態で分散した構成を有する感圧体であって、その空隙率が２５％以上、５５％以下であり、加圧による前記第一の粉体と第二の粉体および前記第二の粉体同士の接触状態が変化して電気抵抗が変化する感圧体に一対の電極を設け、前記感圧体をセラミックス又は金属素材よりなる受圧体で挟み、前記感圧体の外周部を金属又はセラミックス焼結体のような高強度部材からなる外周保持体で囲ってなることを特徴とする感圧素子。 A first powder composed of a powder containing any one selected from the group consisting of Si 3 N 4 , epoxy resin, SiC, Al 2 O 3 , ZrO 2 and SiO 2 , C, SiC, TiN, and hollow C The second powder in the first powder obtained without forming and sintering a mixed powder having a second powder composed of a powder containing any one selected from the group consisting of Is a pressure-sensitive body having a configuration in which a conductive path is formed, the porosity of which is 25% or more and 55% or less, and the first powder and the second powder by pressurization A pair of electrodes is provided on a pressure-sensitive body in which a contact state between the body and the second powder changes to change electric resistance , the pressure-sensitive body is sandwiched between pressure-receiving bodies made of ceramics or a metal material, and the pressure-sensitive body Whether the outer periphery of the body is a high-strength member such as a metal or ceramic sintered body A pressure-sensitive element characterized by being surrounded by an outer peripheral holding body. 前記第二の粉体の電気抵抗率は前記第一の粉体の電気抵抗率と同じかそれ以下であって１００Ω・ｍ以下である請求項１に記載の感圧素子。 2. The pressure-sensitive element according to claim 1, wherein the electrical resistivity of the second powder is equal to or less than that of the first powder and is 100 Ω · m or less. ＪＩＳ：Ｒ１６０１に基づき、支点間距離を７ｍｍとして３点曲げ試験を行った場合の曲げ強度が０．１ＭＰa以上、２０ＭＰａ以下である請求項１又は２に記載の感圧素子。 3. The pressure-sensitive element according to claim 1, wherein the bending strength is 0.1 MPa or more and 20 MPa or less when a three-point bending test is performed based on JIS: R1601 with a distance between supporting points of 7 mm. 前記第二の粉体がカーボンである請求項１乃至３のいずれかに記載の感圧素子。 Sensitive element according to any one of claims 1 to 3 wherein the second powder is carbon. 前記第二の粉体を５ｖｏｌ％以上、４０ｖｏｌ％以下含有する請求項４に記載の感圧素子。 The pressure sensitive element according to claim 4 , wherein the second powder is contained in an amount of 5 vol% or more and 40 vol% or less. 前記電極と前記受圧体とが同一部材である請求項１〜５の何れかに記載の感圧素子。 The pressure sensitive element according to claim 1, wherein the electrode and the pressure receiving body are the same member. 前記外周保持体と感圧体とが接する面には絶縁材が介在してなる請求項１〜６の何れかに記載の感圧素子。 The pressure-sensitive element according to claim 1, wherein an insulating material is interposed on a surface where the outer periphery holding body and the pressure-sensitive body are in contact with each other . 前記外周保持体はヤング率１００ＧＰａ以上の材料からなる請求項１〜７の何れかに記載の感圧素子。 The pressure-sensitive element according to claim 1, wherein the outer peripheral holding body is made of a material having a Young's modulus of 100 GPa or more. 前記感圧体に１０ＭＰａ以上の予圧が負荷されている請求項１〜８の何れかに記載の感圧素子。 The pressure-sensitive element according to claim 1 , wherein a preload of 10 MPa or more is applied to the pressure-sensitive body. 前記感圧素子がリング形状である請求項１〜９の何れかに記載の感圧素子。 The pressure sensitive element according to any one of claims 1 to 9, wherein the pressure sensitive element has a ring shape. 請求項１〜１０の何れかに記載の感圧素子に１０ＭＰａ以上の予圧を負荷した状態で圧力を検出することを特徴とする圧力検出方法。
Pressure detection method characterized by detecting a pressure in a state loaded with more preload 10MPa pressure sensitive element according to any one of claims 1 to 10.
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