JP6764770B2 - Internal combustion engine with pressure detector and pressure detector - Google Patents

Internal combustion engine with pressure detector and pressure detector Download PDF

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JP6764770B2
JP6764770B2 JP2016229471A JP2016229471A JP6764770B2 JP 6764770 B2 JP6764770 B2 JP 6764770B2 JP 2016229471 A JP2016229471 A JP 2016229471A JP 2016229471 A JP2016229471 A JP 2016229471A JP 6764770 B2 JP6764770 B2 JP 6764770B2
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pressure
end side
housing
hole
tubular
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JP2018084561A (en
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亜木 須藤
亜木 須藤
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Citizen Watch Co Ltd
Citizen Fine Device Co Ltd
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Citizen Watch Co Ltd
Citizen Fine Device Co Ltd
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Description

本発明は、圧力検出装置および圧力検出装置付き内燃機関に関する。 The present invention relates to a pressure detector and an internal combustion engine with a pressure detector.

特許文献１には、筒状のハウジング（胴体部）と、ハウジングの先端側に取り付けられるダイアフラムヘッド（受圧部）と、ハウジング内の軸方向であってダイアフラムヘッドの後端側に配置され、ダイアフラムヘッドを介して作用する圧力を検出する圧電素子（信号発生部）とを備えた圧力検出装置を、内燃機関のシリンダブロックに設けられた連通孔に挿入することで、ダイアフラムヘッドを燃焼室に対向させて配置することが記載されている。 In Patent Document 1, a tubular housing (body portion), a diaphragm head (pressure receiving portion) attached to the tip end side of the housing, and a diaphragm arranged in the housing in the axial direction on the rear end side of the diaphragm head. By inserting a pressure detection device equipped with a piezoelectric element (signal generator) that detects the pressure acting through the head into the communication hole provided in the cylinder block of the internal combustion engine, the diaphragm head faces the combustion chamber. It is described that it is arranged.

特開２０１３−１７４５５２号公報Japanese Unexamined Patent Publication No. 2013-174552

ここで、受圧部が受けた圧力を信号発生部に伝達する構成を採用した場合、受圧部に圧力とともに熱が加えられると、受圧部が熱膨張によって変形し、受圧部から信号発生部に伝達される圧力が、本来伝達されるべき大きさに比べて増加または減少するという事態が生じる。すると、信号発生部で生じる出力値が、本来出力されるべき大きさに比べて増加または減少することとなってしまい、信号発生部の出力に基づいて求められる圧力に誤差が含まれることになってしまう。 Here, when a configuration is adopted in which the pressure received by the pressure receiving unit is transmitted to the signal generating unit, when heat is applied to the pressure receiving unit together with the pressure, the pressure receiving unit is deformed by thermal expansion and transmitted from the pressure receiving unit to the signal generating unit. A situation occurs in which the pressure applied increases or decreases with respect to the magnitude that should be transmitted. Then, the output value generated by the signal generator will increase or decrease compared to the magnitude that should be output, and the pressure obtained based on the output of the signal generator will include an error. It ends up.

本発明は、圧力を受ける受圧部の熱膨張に起因する出力値の誤差を低減することを目的とする。 An object of the present invention is to reduce an error in the output value due to thermal expansion of a pressure receiving portion that receives pressure.

本発明の圧力検出装置は、筒状の胴体部と、筒状の筒状部と当該筒状部の一端部側で当該筒状部を塞ぐ閉塞部とを有し、当該筒状部の他端部側が前記胴体部の一端部側に設けられるとともに当該閉塞部が外部から圧力を受ける受圧部と、前記胴体部の内側に設けられ、前記受圧部が受けた圧力に応じた信号を発生する信号発生部と、前記受圧部よりも熱伝導率が低い無機材料で構成され、前記筒状部の外側に取り付けられる環状の環状部材とを含む。
ここで、前記環状部材における一端部側の面が前記受圧部に設けられた突き当て面に対向して配置され、当該環状部材における他端部側の面が前記胴体部に設けられた他の突き当て面に対向して配置されるとよい。
また、他の観点から捉えると、本発明の圧力検出装置付き内燃機関は、先端部側となる燃焼室内と後端部側となる外部とを連通する連通孔が形成されたシリンダヘッドと、前記連通孔に挿入されることで前記シリンダヘッドに取り付けられるとともに、前記燃焼室内の圧力を検出する圧力検出装置とを備え、前記圧力検出装置は、前記連通孔内に配置される筒状の胴体部と、筒状の筒状部と当該筒状部の一端部側で当該筒状部を塞ぐ閉塞部とを有し、当該筒状部の他端部側が前記胴体部の一端部側に設けられるとともに当該閉塞部が前記燃焼室から圧力を受ける受圧部と、前記胴体部の内側に設けられ、前記受圧部が受けた圧力に応じた信号を発生する信号発生部と、前記受圧部よりも熱伝導率が低い無機材料で構成され、前記筒状部の外側に取り付けられるとともに、前記連通孔の内周面と非接触に配置される環状の環状部材とを含む。 The pressure detecting device of the present invention has a tubular body portion, a tubular tubular portion, and a closing portion that closes the tubular portion on one end side of the tubular portion, and other than the tubular portion. The end side is provided on one end side of the body portion, and the closed portion is provided on the pressure receiving portion that receives pressure from the outside and the inside of the body portion, and generates a signal corresponding to the pressure received by the pressure receiving portion. It includes a signal generating portion and an annular member made of an inorganic material having a thermal conductivity lower than that of the pressure receiving portion and attached to the outside of the tubular portion.
Here, the surface on the one end side of the annular member is arranged to face the abutting surface provided on the pressure receiving portion, and the surface on the other end side of the annular member is provided on the body portion. It is preferable to arrange them so as to face the abutting surface.
From another point of view, the internal combustion engine with a pressure detection device of the present invention has a cylinder head having a communication hole for communicating between the combustion chamber on the front end side and the outside on the rear end side, and the above. It is attached to the cylinder head by being inserted into the communication hole, and also includes a pressure detecting device for detecting the pressure in the combustion chamber. The pressure detecting device is a tubular body portion arranged in the communication hole. And a tubular portion and a closing portion that closes the tubular portion on one end side of the tubular portion, and the other end side of the tubular portion is provided on the one end side of the body portion. At the same time, the closed portion receives pressure from the combustion chamber, a signal generating portion provided inside the body portion and generating a signal corresponding to the pressure received by the pressure receiving portion, and heat from the pressure receiving portion. It is made of an inorganic material having a low conductivity, is attached to the outside of the tubular portion, and includes an annular member arranged in a non-contact manner with the inner peripheral surface of the communication hole.

本発明によれば、圧力を受ける受圧部の熱膨張に起因する出力値の誤差を低減することができる。 According to the present invention, it is possible to reduce an error in the output value due to thermal expansion of the pressure receiving portion that receives pressure.

実施の形態に係る内燃機関の概略構成図である。It is a schematic block diagram of the internal combustion engine which concerns on embodiment. 図１のＩＩ部の拡大図である。It is an enlarged view of the part II of FIG. 圧力検出装置の概略構成図である。It is a schematic block diagram of a pressure detection device. 図３のＩＶ−ＩＶ部の断面図である。It is sectional drawing of the IV-IV part of FIG. 図４のＶ部の拡大図である。It is an enlarged view of the V part of FIG. 図５のＶＩ部の拡大図である。It is an enlarged view of the VI part of FIG. 圧力検出装置における第１のハウジング、ダイアフラムヘッドおよび抑制リングの分解斜視図である。FIG. 3 is an exploded perspective view of a first housing, a diaphragm head, and a restraining ring in a pressure detector. （ａ）は従来の圧力検出装置を用いた場合における出力値の時間経過を、（ｂ）は今回の圧力検出装置を用いた場合における出力値の時間経過を、それぞれ示す図である。(A) is a diagram showing the time passage of an output value when a conventional pressure detection device is used, and (b) is a diagram showing the time passage of an output value when the current pressure detection device is used.

以下、添付図面を参照して、本発明の実施の形態について詳細に説明する。
［内燃機関］
図１は、本実施の形態に係る内燃機関１の概略構成図である。
図２は、図１のＩＩ部の拡大図である。
内燃機関１は、シリンダ２ａを有するシリンダブロック２と、シリンダ２ａ内を往復動するピストン３と、シリンダブロック２に締結されてシリンダ２ａおよびピストン３などとともに燃焼室Ｃを形成するシリンダヘッド４と、を備えている。また、内燃機関１は、シリンダヘッド４に装着されて燃焼室Ｃ内の圧力を検出する圧力検出装置５と、圧力検出装置５が検出した圧力に基づいて内燃機関１の作動を制御する制御装置６と、圧力検出装置５とシリンダヘッド４との間に介在して燃焼室Ｃ内の気密性を保つためのシール部材７と、圧力検出装置５と制御装置６との間で電気信号を伝送する伝送ケーブル８と、を備えている。 Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
[Internal combustion engine]
FIG. 1 is a schematic configuration diagram of an internal combustion engine 1 according to the present embodiment.
FIG. 2 is an enlarged view of part II of FIG.
The internal combustion engine 1 includes a cylinder block 2 having a cylinder 2a, a piston 3 that reciprocates in the cylinder 2a, a cylinder head 4 that is fastened to the cylinder block 2 and forms a combustion chamber C together with the cylinder 2a and the piston 3. Is equipped with. Further, the internal combustion engine 1 is a pressure detection device 5 mounted on the cylinder head 4 to detect the pressure in the combustion chamber C, and a control device for controlling the operation of the internal combustion engine 1 based on the pressure detected by the pressure detection device 5. An electric signal is transmitted between the pressure detection device 5 and the control device 6 and the seal member 7 which is interposed between the pressure detection device 5 and the cylinder head 4 to maintain the airtightness in the combustion chamber C. The transmission cable 8 and the like are provided.

シリンダヘッド４には、燃焼室Ｃと外部とを連通する連通孔４ａが形成されている。連通孔４ａは、燃焼室Ｃ側から、第１の孔部４ｂと、第１の孔部４ｂの孔径から徐々に径が拡大している傾斜部４ｃと、第１の孔部４ｂの孔径よりも孔径が大きい第２の孔部４ｄと、を有している。第２の孔部４ｄを形成する周囲の壁には、圧力検出装置５に形成された後述するハウジング３０の雄ねじ３３２ａがねじ込まれる雌ねじ４ｅが形成されている。 The cylinder head 4 is formed with a communication hole 4a that communicates the combustion chamber C with the outside. From the combustion chamber C side, the communication hole 4a is formed from the hole diameters of the first hole portion 4b, the inclined portion 4c whose diameter gradually increases from the hole diameter of the first hole portion 4b, and the hole diameter of the first hole portion 4b. Also has a second hole 4d with a large hole diameter. On the peripheral wall forming the second hole 4d, a female screw 4e into which the male screw 332a of the housing 30 described later, which is formed in the pressure detecting device 5, is screwed is formed.

［圧力検出装置］
以下に、圧力検出装置５について詳述する。
図３は、圧力検出装置５の概略構成図である。図４は、図３のＩＶ−ＩＶ部の断面図である。図５は、図４のＶ部の拡大図である。図６は、図５のＶＩ部の拡大図である。図７は、圧力検出装置５における第１のハウジング３１、ダイアフラムヘッド４０および抑制リング８０の分解斜視図である。 [Pressure detector]
The pressure detection device 5 will be described in detail below.
FIG. 3 is a schematic configuration diagram of the pressure detection device 5. FIG. 4 is a cross-sectional view of the IV-IV portion of FIG. FIG. 5 is an enlarged view of the V portion of FIG. FIG. 6 is an enlarged view of the VI portion of FIG. FIG. 7 is an exploded perspective view of the first housing 31, the diaphragm head 40, and the restraining ring 80 in the pressure detecting device 5.

圧力検出装置５は、燃焼室Ｃ内の圧力を電気信号に変換する圧電素子１０を有するセンサ部１００と、センサ部１００からの電気信号を処理する信号処理部２００と、信号処理部２００を保持する保持部材３００と、を備えている。この圧力検出装置５をシリンダヘッド４に装着する際には、センサ部１００の後述するダイアフラムヘッド４０の方から先に、シリンダヘッド４に形成された連通孔４ａに挿入していく。以下の説明において、図４の左側を圧力検出装置５の先端側、右側を圧力検出装置５の後端側とする。 The pressure detection device 5 holds a sensor unit 100 having a piezoelectric element 10 that converts the pressure in the combustion chamber C into an electric signal, a signal processing unit 200 that processes an electric signal from the sensor unit 100, and a signal processing unit 200. The holding member 300 and the holding member 300 are provided. When the pressure detecting device 5 is attached to the cylinder head 4, the diaphragm head 40, which will be described later, of the sensor unit 100 is inserted into the communication hole 4a formed in the cylinder head 4 first. In the following description, the left side of FIG. 4 is the front end side of the pressure detection device 5, and the right side is the rear end side of the pressure detection device 5.

（センサ部）
先ずは、センサ部１００について説明する。
センサ部１００は、受けた圧力を電気信号に変換する圧電素子１０と、筒状であってその内部に圧電素子１０などを収納する円柱状の孔が形成されたハウジング３０と、を備えている。以下では、ハウジング３０に形成された円柱状の孔の中心線方向を、単に中心線方向と称す。
また、センサ部１００は、ハウジング３０における先端側の開口部を塞ぐように設けられて、燃焼室Ｃ内の圧力が作用するダイアフラムヘッド４０と、ダイアフラムヘッド４０と圧電素子１０との間に設けられた第１の電極部５０と、圧電素子１０に対して第１の電極部５０とは反対側に配置された第２の電極部５５と、を備えている。
また、センサ部１００は、第２の電極部５５を電気的に絶縁する絶縁リング６０と、絶縁リング６０よりも後端側に設けられて、信号処理部２００の後述する覆い部材２３の端部を支持する支持部材６５と、第２の電極部５５と後述する伝導部材２２との間に介在するコイルスプリング７０と、ダイアフラムヘッド４０の外周面における後端側に設けられて、外部からダイアフラムヘッド４０への熱の進入を抑制する抑制リング８０と、を備えている。 (Sensor part)
First, the sensor unit 100 will be described.
The sensor unit 100 includes a piezoelectric element 10 that converts the received pressure into an electric signal, and a housing 30 that is tubular and has a cylindrical hole for accommodating the piezoelectric element 10 and the like. .. Hereinafter, the direction of the center line of the columnar hole formed in the housing 30 is simply referred to as the center line direction.
Further, the sensor unit 100 is provided so as to close the opening on the distal end side of the housing 30, and is provided between the diaphragm head 40 on which the pressure in the combustion chamber C acts, and between the diaphragm head 40 and the piezoelectric element 10. A first electrode portion 50 and a second electrode portion 55 arranged on the opposite side of the piezoelectric element 10 from the first electrode portion 50 are provided.
Further, the sensor unit 100 is provided with an insulating ring 60 that electrically insulates the second electrode unit 55 and an end portion of a covering member 23 described later of the signal processing unit 200, which is provided on the rear end side of the insulating ring 60. A coil spring 70 interposed between the support member 65 supporting the support member 65, the second electrode portion 55, and the conduction member 22 described later, and the diaphragm head provided on the rear end side of the outer peripheral surface of the diaphragm head 40 from the outside. It is provided with a suppression ring 80 that suppresses the ingress of heat into the 40.

信号発生部の一例としての圧電素子１０は、圧電縦効果の圧電作用を示す圧電体を有している。圧電縦効果とは、圧電体の電荷発生軸と同一方向の応力印加軸に外力を作用させると、電荷発生軸方向の圧電体の表面に電荷が発生する作用をいう。本実施形態に係る圧電素子１０は、中心線方向が応力印加軸の方向となるようにハウジング３０内に収納されている。 The piezoelectric element 10 as an example of the signal generation unit has a piezoelectric body that exhibits a piezoelectric action of a piezoelectric vertical effect. The piezoelectric longitudinal effect refers to an action in which a charge is generated on the surface of the piezoelectric body in the direction of the charge generation axis when an external force is applied to the stress application axis in the same direction as the charge generation axis of the piezoelectric body. The piezoelectric element 10 according to the present embodiment is housed in the housing 30 so that the center line direction is the direction of the stress application axis.

次に、圧電素子１０に圧電横効果を利用した場合を例示する。圧電横効果とは、圧電体の電荷発生軸に対して直交する位置にある応力印加軸に外力を作用させると、電荷発生軸方向の圧電体の表面に電荷が発生する作用をいう。薄板状に薄く形成した圧電体を複数枚積層して構成しても良く、このように積層することで、圧電体に発生する電荷を効率的に集めてセンサの感度を上げることができる。圧電単結晶としては、圧電縦効果及び圧電横効果を有するランガサイト系結晶（ランガサイト、ランガテイト、ランガナイト、ガリウムの一部をアルミニウムで置換したランガテイト（ＬＴＧＡ））や水晶、ガリウムリン酸塩などを使用することを例示することができる。なお、本実施形態の圧電素子１０には、圧電体としてランガサイト単結晶を用いている。 Next, a case where the piezoelectric lateral effect is used for the piezoelectric element 10 will be illustrated. The piezoelectric lateral effect refers to an action in which a charge is generated on the surface of a piezoelectric body in the direction of the charge generation axis when an external force is applied to a stress application axis located at a position orthogonal to the charge generation axis of the piezoelectric body. A plurality of piezoelectric bodies formed thinly in the shape of a thin plate may be laminated, and by laminating in this way, the electric charge generated in the piezoelectric body can be efficiently collected to increase the sensitivity of the sensor. Piezoelectric single crystals include langateite crystals (langasite, langateite, langanite, langatete (LTGA) in which a part of gallium is replaced with aluminum), quartz, gallium phosphate, etc., which have piezoelectric longitudinal effect and piezoelectric lateral effect. Can be illustrated to be used. The piezoelectric element 10 of the present embodiment uses a Langasite single crystal as the piezoelectric material.

ハウジング３０は、先端側に設けられた第１のハウジング３１と、後端側に設けられた第２のハウジング３２と、を有する。
胴体部の一例としての第１のハウジング３１は、内部に、先端側から後端側にかけて段階的に径が異なるように形成された円柱状の孔３１０が形成された薄肉円筒状の部材である。外周面には、中心線方向の中央部に、外周面から突出する突出部３１５が周方向の全域に渡って設けられている。
孔３１０は、先端側から後端側にかけて順に形成された、第１の孔３１１と、第１の孔３１１の孔径よりも大きな孔径の第２の孔３１２と、から構成される。突出部３１５は、先端部に、先端側から後端側にかけて徐々に径が大きくなる傾斜面３１５ａを有し、後端部に、中心線方向に垂直な垂直面３１５ｂを有している。 The housing 30 has a first housing 31 provided on the front end side and a second housing 32 provided on the rear end side.
The first housing 31 as an example of the body portion is a thin-walled cylindrical member in which cylindrical holes 310 formed so as to have different diameters stepwise from the front end side to the rear end side are formed inside. .. On the outer peripheral surface, a protruding portion 315 protruding from the outer peripheral surface is provided at the central portion in the center line direction over the entire area in the circumferential direction.
The hole 310 is composed of a first hole 311 formed in order from the front end side to the rear end side, and a second hole 312 having a hole diameter larger than the hole diameter of the first hole 311. The protruding portion 315 has an inclined surface 315a whose diameter gradually increases from the front end side to the rear end side at the front end portion, and has a vertical surface 315b perpendicular to the center line direction at the rear end portion.

第２のハウジング３２は、内部に、先端側から後端側にかけて段階的に径が異なるように形成された円柱状の孔３２０が形成された筒状の部材であり、外部に、先端側から後端側にかけて段階的に径が異なるように形成された外周面３３０が設けられている。
孔３２０は、先端側から後端側にかけて順に形成された、第１の孔３２１と、第１の孔３２１の孔径よりも小さな孔径の第２の孔３２２と、第２の孔３２２の孔径よりも大きな孔径の第３の孔３２３と、第３の孔３２３の孔径よりも大きな孔径の第４の孔３２４と、第４の孔３２４の孔径よりも大きな孔径の第５の孔３２５と、から構成される。
第２のハウジング３２における先端部は、第１のハウジング３１における後端部にしまりばめで嵌合（圧入）されるように、第１の孔３２１の孔径は、第１のハウジング３１の外周面の径以下となるように設定されている。 The second housing 32 is a tubular member in which columnar holes 320 formed so as to have different diameters stepwise from the front end side to the rear end side are formed inside, and is externally from the front end side. An outer peripheral surface 330 formed so that the diameter is gradually different toward the rear end side is provided.
The holes 320 are formed from the first hole 321 and the second hole 322 having a hole diameter smaller than the hole diameter of the first hole 321 and the hole diameter of the second hole 322, which are formed in order from the front end side to the rear end side. From the third hole 323 with a large hole diameter, the fourth hole 324 with a hole diameter larger than the hole diameter of the third hole 323, and the fifth hole 325 with a hole diameter larger than the hole diameter of the fourth hole 324. It is composed.
The hole diameter of the first hole 321 is the outer peripheral surface of the first housing 31 so that the tip end portion of the second housing 32 is fitted (press-fitted) to the rear end portion of the first housing 31 by fitting. It is set to be less than or equal to the diameter of.

外周面３３０は、先端側から後端側にかけて、第１の外周面３３１と、第１の外周面３３１の外径よりも大きな外径の第２の外周面３３２と、第２の外周面３３２の外径よりも大きな外径の第３の外周面３３３と、第３の外周面３３３の外径よりも大きな外径の第４の外周面３３４と、第４の外周面３３４の外径よりも小さな外径の第５の外周面３３５と、から構成される。第２の外周面３３２における先端部には、シリンダヘッド４の雌ねじ４ｅにねじ込まれる雄ねじ３３２ａが形成されている。第３の外周面３３３には、後述する第１のシール部材７１がすきまばめで嵌め込まれ、第３の外周面３３３の外径と第１のシール部材７１の内径との寸法公差は、例えば零から０．２ｍｍとなるように設定される。第４の外周面３３４における後端部は、周方向に等間隔に６つの面取りを有する正六角柱に形成されている。この正六角柱に形成された部位が、圧力検出装置５をシリンダヘッド４に締め付ける際に、締付用の工具が嵌め込まれ、工具に付与された回転力が伝達される部位となる。第５の外周面３３５における中心線方向の中央部には、外周面から凹んだ凹部３３５ａが全周に渡って形成されている。 The outer peripheral surface 330 has a first outer peripheral surface 331, a second outer peripheral surface 332 having an outer diameter larger than the outer diameter of the first outer peripheral surface 331, and a second outer peripheral surface 332 from the front end side to the rear end side. From the outer diameter of the third outer peripheral surface 333 having an outer diameter larger than the outer diameter of, the fourth outer peripheral surface 334 having an outer diameter larger than the outer diameter of the third outer diameter surface 333, and the outer diameter of the fourth outer peripheral surface 334. Is also composed of a fifth outer peripheral surface 335 having a small outer diameter. At the tip of the second outer peripheral surface 332, a male screw 332a screwed into the female screw 4e of the cylinder head 4 is formed. A first sealing member 71, which will be described later, is fitted into the third outer peripheral surface 333 by a clearance fit, and the dimensional tolerance between the outer diameter of the third outer peripheral surface 333 and the inner diameter of the first sealing member 71 is, for example, zero. It is set to be 0.2 mm from. The rear end portion of the fourth outer peripheral surface 334 is formed as a regular hexagonal prism having six chamfers at equal intervals in the circumferential direction. The portion formed on the regular hexagonal prism is a portion where the tightening tool is fitted when the pressure detection device 5 is tightened to the cylinder head 4, and the rotational force applied to the tool is transmitted. A recess 335a recessed from the outer peripheral surface is formed over the entire circumference at the central portion of the fifth outer peripheral surface 335 in the direction of the center line.

また、第２のハウジング３２は、第４の孔３２４から第５の孔３２５への移行部分であり、第５の孔３２５における先端部には、信号処理部２００の後述する覆い部材２３の基板被覆部２３２における先端側の端面が突き当たる突当面３４０が設けられている。突当面３４０には、後述する信号処理部２００のプリント配線基板２１０の第２の接続ピン２１ｂが差し込まれるピン用凹部３４０ａが形成されている。 Further, the second housing 32 is a transition portion from the fourth hole 324 to the fifth hole 325, and the tip portion of the fifth hole 325 is a substrate of a covering member 23 described later of the signal processing unit 200. An abutting surface 340 is provided on which the end surface of the covering portion 232 on the distal end side abuts. The abutting surface 340 is formed with a pin recess 340a into which a second connection pin 21b of the printed wiring board 210 of the signal processing unit 200, which will be described later, is inserted.

第１のハウジング３１および第２のハウジング３２は、燃焼室Ｃに近い位置に存在するため、少なくとも、−４０〜３５０〔℃〕の使用温度環境に耐える材料を用いて製作することが望ましい。具体的には、耐熱性の高いステンレス鋼材、例えば、ＪＩＳ規格のＳＵＳ６３０、ＳＵＳ３１６、ＳＵＳ４３０等を用いることが望ましい。 Since the first housing 31 and the second housing 32 are located close to the combustion chamber C, it is desirable to manufacture the first housing 31 and the second housing 32 using a material that can withstand an operating temperature environment of at least -40 to 350 [° C.]. Specifically, it is desirable to use a stainless steel material having high heat resistance, for example, JIS standard SUS630, SUS316, SUS430 and the like.

受圧部の一例としてのダイアフラムヘッド４０は、円筒状を呈する筒状部４１と、板状を呈するとともに筒状部４１の先端側に設けられて筒状部４１の先端側を塞ぐ閉塞部４２と、を有している。また、ダイアフラムヘッド４０は、筒状部４１と閉塞部４２との境界部における外周面を４５°に面取加工することで設けられた面取部４３をさらに有している。ダイアフラムヘッド４０の材料としては、高温でありかつ高圧となる燃焼室Ｃ内に存在するため、弾性が高く、かつ耐久性、耐熱性、耐触性等に優れた合金製であることが望ましく、例えばＳＵＨ６６０であることを例示することができる。 The diaphragm head 40 as an example of the pressure receiving portion includes a cylindrical portion 41 having a cylindrical shape and a closing portion 42 having a plate shape and being provided on the tip end side of the tubular portion 41 to close the tip end side of the tubular portion 41. ,have. Further, the diaphragm head 40 further has a chamfered portion 43 provided by chamfering the outer peripheral surface at the boundary portion between the tubular portion 41 and the closed portion 42 at 45 °. Since the diaphragm head 40 exists in the combustion chamber C having a high temperature and a high pressure, it is desirable that the diaphragm head 40 is made of an alloy having high elasticity and excellent durability, heat resistance, touch resistance, and the like. For example, it can be exemplified as SUH660.

筒状部４１は、面取部４３に隣接することで最も先端側に位置する先端筒状部４１１と、先端筒状部４１１の後端側に位置する中間筒状部４１２と、中間筒状部４１２の後端側であって最も後端側に位置する後端筒状部４１３と、を有している。この筒状部４１では、先端筒状部４１１よりも中間筒状部４１２の外径が小さくなっており、中間筒状部４１２よりも後端筒状部４１３の外径が小さくなっている。また、筒状部４１は、先端筒状部４１１と中間筒状部４１２との境界部において両者を接続する先端段差部４１４と、中間筒状部４１２と後端筒状部４１３との境界部において両者を接続する後端段差部４１５と、をさらに有している。なお、筒状部４１の内径は、軸方向の位置によらず同じである。 The tubular portion 41 has an intermediate tubular portion 411 located closest to the tip side by being adjacent to the chamfered portion 43, an intermediate tubular portion 412 located on the rear end side of the tip tubular portion 411, and an intermediate tubular portion. It has a rear end tubular portion 413 which is located on the rear end side of the portion 412 and is located on the rearmost end side. In this tubular portion 41, the outer diameter of the intermediate tubular portion 412 is smaller than that of the tip tubular portion 411, and the outer diameter of the rear end tubular portion 413 is smaller than that of the intermediate tubular portion 412. Further, the tubular portion 41 is a boundary portion between the tip step portion 414 connecting the tip tubular portion 411 and the intermediate tubular portion 412 and the intermediate tubular portion 412 and the rear end tubular portion 413. Further, it has a rear end stepped portion 415 that connects the two. The inner diameter of the tubular portion 41 is the same regardless of the position in the axial direction.

閉塞部４２は、先端側すなわちその表面の中央部に設けられ、圧電素子１０側に凹んだ表面凹部４２１と、後端側すなわちその裏面の中央部に設けられ、圧電素子１０側に突出した裏面凸部４２２と、を有している。この閉塞部４２では、表面凹部４２１の背面に裏面凸部４２２が位置している。 The closing portion 42 is provided on the front end side, that is, the central portion of the surface thereof, and is provided on the front end side, that is, the central portion on the back surface thereof, which is recessed on the piezoelectric element 10 side, and the back surface protruding toward the piezoelectric element 10. It has a convex portion 422 and. In the closed portion 42, the back surface convex portion 422 is located on the back surface of the front surface concave portion 421.

第１の電極部５０は、先端側から後端側にかけて段階的に径が異なるように形成された円柱状の部材であり、第１の円柱部５１と、第１の円柱部５１の外径よりも大きな外径の第２の円柱部５２と、から構成される。第１の円柱部５１の外径はダイアフラムヘッド４０の筒状部４１の内径よりも小さく、第２の円柱部５２の外径は第１のハウジング３１の第１の孔３１１の孔径と略同じである。そして、第１の円柱部５１における先端側の端面がダイアフラムヘッド４０の閉塞部４２の裏面凸部４２２と、第２の円柱部５２における後端側の端面が圧電素子１０における先端側の面と接触するように配置される。第２の円柱部５２の外周面が第１のハウジング３１の内周面と接触すること、および／または第１の円柱部５１における先端側の端面がダイアフラムヘッド４０と接触することによって、圧電素子１０における先端部は、ハウジング３０と電気的に接続される。
第１の電極部５０は、燃焼室Ｃ内の圧力を圧電素子１０に作用させるものであり、圧電素子１０側の端面である第２の円柱部５２における後端側の端面が圧電素子１０の端面の全面を押すことが可能な大きさに形成される。また、第１の電極部５０は、ダイアフラムヘッド４０から受ける圧力を均等に圧電素子１０に作用させることができるように、中心線方向の両端面が平行（中心線方向に直交）かつ平滑面に形成されている。
第１の電極部５０の材質としては、ステンレスであることを例示することができる。 The first electrode portion 50 is a columnar member formed so as to have a stepwise different diameter from the front end side to the rear end side, and the outer diameters of the first columnar portion 51 and the first columnar portion 51. It is composed of a second cylindrical portion 52 having a larger outer diameter. The outer diameter of the first cylindrical portion 51 is smaller than the inner diameter of the tubular portion 41 of the diaphragm head 40, and the outer diameter of the second cylindrical portion 52 is substantially the same as the hole diameter of the first hole 311 of the first housing 31. Is. Then, the end surface on the front end side of the first cylindrical portion 51 is the back surface convex portion 422 of the closing portion 42 of the diaphragm head 40, and the end surface on the rear end side of the second cylindrical portion 52 is the front end side surface of the piezoelectric element 10. Arranged to touch. The piezoelectric element is formed by contacting the outer peripheral surface of the second cylindrical portion 52 with the inner peripheral surface of the first housing 31 and / or contacting the end surface of the first cylindrical portion 51 on the distal end side with the diaphragm head 40. The tip of the 10 is electrically connected to the housing 30.
The first electrode portion 50 causes the pressure in the combustion chamber C to act on the piezoelectric element 10, and the end face on the rear end side of the second cylindrical portion 52, which is the end face on the piezoelectric element 10 side, is the piezoelectric element 10. It is formed to a size that can push the entire surface of the end face. Further, in the first electrode portion 50, both end faces in the center line direction are parallel (orthogonal in the center line direction) and smooth so that the pressure received from the diaphragm head 40 can be evenly applied to the piezoelectric element 10. It is formed.
It can be exemplified that the material of the first electrode portion 50 is stainless steel.

第２の電極部５５は、円柱状の部材であり、先端側の端面が圧電素子１０における後端側の端面に接触し、一方の端部側の端面が絶縁リング６０に接触するように配置される。第２の電極部５５における後端側の端面には、この端面から後端側に突出する円柱状の突出部５５ａが設けられている。突出部５５ａは、端面側の基端部と、この基端部の外径よりも小さな外径の先端部と、を有する。突出部５５ａの外径は絶縁リング６０の内径よりも小さく設定されるとともに、突出部５５ａの長さは絶縁リング６０の幅（中心線方向の長さ）よりも長く設定され、突出部５５ａの先端が絶縁リング６０から露出している。この第２の電極部５５は、第１の電極部５０との間で圧電素子１０に対して一定の荷重を加えるように作用する部材であり、圧電素子１０側の端面は、圧電素子１０の端面の全面を押すことが可能な大きさに形成されるとともに平行かつ平滑面に形成されている。第２の電極部５５の外径は第１のハウジング３１の第２の孔３１２の孔径よりも小さくなるように設定されており、第２の電極部５５の外周面と第１のハウジング３１の内周面との間には隙間がある。
第２の電極部５５の材質としては、ステンレスであることを例示することができる。 The second electrode portion 55 is a columnar member, and is arranged so that the end face on the front end side contacts the end face on the rear end side of the piezoelectric element 10 and the end face on one end side contacts the insulating ring 60. Will be done. A columnar projecting portion 55a projecting from the end surface to the rear end side is provided on the rear end side end surface of the second electrode portion 55. The protruding portion 55a has a base end portion on the end face side and a tip portion having an outer diameter smaller than the outer diameter of the base end portion. The outer diameter of the protruding portion 55a is set smaller than the inner diameter of the insulating ring 60, and the length of the protruding portion 55a is set longer than the width (length in the center line direction) of the insulating ring 60. The tip is exposed from the insulating ring 60. The second electrode portion 55 is a member that acts to apply a constant load to the piezoelectric element 10 with the first electrode portion 50, and the end face on the piezoelectric element 10 side is the piezoelectric element 10. It is formed to a size that can push the entire surface of the end face, and is formed to be parallel and smooth. The outer diameter of the second electrode portion 55 is set to be smaller than the hole diameter of the second hole 312 of the first housing 31, and the outer peripheral surface of the second electrode portion 55 and the first housing 31 There is a gap between it and the inner peripheral surface.
It can be exemplified that the material of the second electrode portion 55 is stainless steel.

絶縁リング６０は、アルミナセラミックス等により形成された円筒状の部材であり、内径（中央部の孔径）は、第２の電極部５５の突出部５５ａの基端部の外径よりもやや大きく、外径は、第１のハウジング３１の第２の孔３１２の孔径と略同じに設定されている。第２の電極部５５は、突出部５５ａが絶縁リング６０の中央部の孔に挿入されて配置されることで、中心位置と第１のハウジング３１の第２の孔３１２の中心とが同じになるように配置される。 The insulating ring 60 is a cylindrical member made of alumina ceramics or the like, and its inner diameter (hole diameter at the center) is slightly larger than the outer diameter of the base end of the protruding portion 55a of the second electrode portion 55. The outer diameter is set to be substantially the same as the hole diameter of the second hole 312 of the first housing 31. The second electrode portion 55 is arranged so that the protruding portion 55a is inserted into the hole at the center of the insulating ring 60 so that the center position and the center of the second hole 312 of the first housing 31 are the same. It is arranged so as to be.

支持部材６５は、先端側から後端側にかけて、内部に、径が異なる複数の円柱状の孔６５０が形成され、外周面が同一の、筒状の部材である。
孔６５０は、先端側から後端側にかけて順に形成された、第１の孔６５１と、第１の孔６５１の孔径よりも大きな孔径の第２の孔６５２と、第２の孔６５２の孔径よりも大きな孔径の第３の孔６５３と、から構成される。第１の孔６５１の孔径は、第２の電極部５５の突出部５５ａの基端部の外径よりも大きく、この突出部５５ａが支持部材６５の内部まで露出する。第２の孔６５２の孔径は、後述する信号処理部２００の伝導部材２２における先端部の外径よりも大きい。第３の孔６５３の孔径は、後述する信号処理部２００の覆い部材２３の端部の外径よりも小さく、この覆い部材２３が第３の孔６５３を形成する周囲の壁にしまりばめで嵌合される。これにより、支持部材６５は、覆い部材２３の端部を支持する部材として機能する。 The support member 65 is a tubular member having a plurality of columnar holes 650 having different diameters formed inside from the front end side to the rear end side and having the same outer peripheral surface.
The holes 650 are formed from the first hole 651, the second hole 652 having a hole diameter larger than the hole diameter of the first hole 651, and the hole diameter of the second hole 652, which are formed in order from the front end side to the rear end side. Also consists of a third hole 653 with a large hole diameter. The hole diameter of the first hole 651 is larger than the outer diameter of the base end portion of the protruding portion 55a of the second electrode portion 55, and the protruding portion 55a is exposed to the inside of the support member 65. The hole diameter of the second hole 652 is larger than the outer diameter of the tip portion of the conduction member 22 of the signal processing unit 200, which will be described later. The hole diameter of the third hole 653 is smaller than the outer diameter of the end portion of the covering member 23 of the signal processing unit 200, which will be described later, and the covering member 23 is fitted into the surrounding wall forming the third hole 653 by fitting. Will be combined. As a result, the support member 65 functions as a member that supports the end portion of the cover member 23.

コイルスプリング７０は、内径が、第２の電極部５５の突出部５５ａの先端部の外径以上で基端部の外径より小さく、外径が、後述する伝導部材２２の挿入孔２２ａの径よりも小さい。コイルスプリング７０の内側に第２の電極部５５の突出部５５ａの先端部が挿入されるとともに、コイルスプリング７０は、後述する伝導部材２２の挿入孔２２ａに挿入される。コイルスプリング７０の長さは、第２の電極部５５と伝導部材２２との間に圧縮した状態で介在することができる長さに設定されている。コイルスプリング７０の材質としては、弾性が高く、かつ耐久性、耐熱性、耐触性等に優れた合金を用いるとよい。また、コイルスプリング７０の表面に金メッキを施すことで、電気伝導を高めるとよい。 The inner diameter of the coil spring 70 is equal to or greater than the outer diameter of the tip of the protruding portion 55a of the second electrode portion 55 and smaller than the outer diameter of the base end portion, and the outer diameter is the diameter of the insertion hole 22a of the conduction member 22 described later. Smaller than The tip of the protruding portion 55a of the second electrode portion 55 is inserted inside the coil spring 70, and the coil spring 70 is inserted into the insertion hole 22a of the conduction member 22 described later. The length of the coil spring 70 is set to a length that can be interposed between the second electrode portion 55 and the conductive member 22 in a compressed state. As the material of the coil spring 70, it is preferable to use an alloy having high elasticity and excellent durability, heat resistance, touch resistance and the like. Further, it is preferable to enhance the electric conduction by plating the surface of the coil spring 70 with gold.

環状部材の一例としての抑制リング８０は、アルミナセラミックス等により形成された円筒状の部材であり、その内径は、ダイアフラムヘッド４０における中間筒状部４１２の外径よりもわずかに大きく、その外径は、ダイアフラムヘッド４０における先端筒状部４１１の外径と略同じに設定されている。また、抑制リング８０は、先端側に設けられるとともにダイアフラムヘッド４０における先端段差部４１４と対向する先端面８１と、後端側に設けられるとともに第１のハウジング３１の端面３１ａに対向する後端面８２と、を有している。 The restraining ring 80 as an example of the annular member is a cylindrical member formed of alumina ceramics or the like, and its inner diameter is slightly larger than the outer diameter of the intermediate tubular portion 412 in the diaphragm head 40, and the outer diameter thereof is slightly larger. Is set to be substantially the same as the outer diameter of the tip cylindrical portion 411 of the diaphragm head 40. Further, the restraining ring 80 is provided on the front end side and is provided on the front end surface 81 facing the tip step portion 414 of the diaphragm head 40, and is provided on the rear end side and is provided on the rear end side and is provided on the rear end surface 82 facing the end surface 31a of the first housing 31. And have.

ではここで、圧力検出装置５の先端側に設けられるダイアフラムヘッド４０および抑制リング８０の特性の関係について、説明しておく。 Here, the relationship between the characteristics of the diaphragm head 40 and the suppression ring 80 provided on the tip side of the pressure detection device 5 will be described.

本実施の形態において、ダイアフラムヘッド４０は、上述したように金属材料（この例ではステンレス）で構成される。これに対し、抑制リング８０は、上述したように無機材料（この例ではアルミナ）で構成される。さらに、本実施の形態の抑制リング８０は、多結晶体すなわちセラミックスで構成される。したがって、本実施の形態では、抑制リング８０の導電率が、ダイアフラムヘッド４０の導電率よりも低くなっている。 In this embodiment, the diaphragm head 40 is made of a metal material (stainless steel in this example) as described above. On the other hand, the suppression ring 80 is made of an inorganic material (alumina in this example) as described above. Further, the suppression ring 80 of the present embodiment is composed of a polycrystalline material, that is, ceramics. Therefore, in the present embodiment, the conductivity of the suppression ring 80 is lower than the conductivity of the diaphragm head 40.

そして、本実施の形態では、抑制リング８０の熱伝導率が、ダイアフラムヘッド４０の熱伝導率よりも低くなるように、各々の材料の選択が行われている。この例において、アルミナセラミックスの熱伝導率は１５〜４５（Ｗ／ｍ・Ｋ）であり、ステンレスの熱伝導率は１６〜２７（Ｗ／ｍ・Ｋ）である。 Then, in the present embodiment, each material is selected so that the thermal conductivity of the suppression ring 80 is lower than the thermal conductivity of the diaphragm head 40. In this example, the thermal conductivity of alumina ceramics is 15 to 45 (W / m · K), and the thermal conductivity of stainless steel is 16 to 27 (W / m · K).

また、本実施の形態では、抑制リング８０の融点が、ダイアフラムヘッド４０の融点よりも高くなるように、各々の材料の選択が行われている。この例において、アルミナセラミックスの融点は２０７２（℃）であり、ステンレスの融点は１４００〜１５００（℃）である。 Further, in the present embodiment, each material is selected so that the melting point of the suppression ring 80 is higher than the melting point of the diaphragm head 40. In this example, the melting point of alumina ceramics is 2072 (° C.) and the melting point of stainless steel is 1400 to 1500 (° C.).

さらに、本実施の形態では、抑制リング８０の線膨張係数が、ダイアフラムヘッド４０の線膨張係数よりも小さくなるように、各々の材料の選択が行われている。この例において、アルミナセラミックスの線膨張係数は７〜８（１０−６／Ｋ）であり、ステンレスの線膨張係数は９〜１８（１０−６／Ｋ）である。 Further, in the present embodiment, each material is selected so that the coefficient of linear expansion of the suppression ring 80 is smaller than the coefficient of linear expansion of the diaphragm head 40. In this example, the coefficient of linear expansion of alumina ceramics is 7 to 8 ( 10-6 / K), and the coefficient of linear expansion of stainless steel is 9 to 18 ( 10-6 / K).

（信号処理部）
次に、信号処理部２００について説明する。
信号処理部２００は、センサ部１００の圧電素子１０から得られる微弱な電荷である電気信号を少なくとも増幅処理する回路基板部２１と、圧電素子１０に生じた電荷を回路基板部２１まで導く棒状の伝導部材２２と、これら回路基板部２１、伝導部材２２などを覆う覆い部材２３と、回路基板部２１などを密封するＯリング２４と、を備えている。 (Signal processing unit)
Next, the signal processing unit 200 will be described.
The signal processing unit 200 has a circuit board unit 21 that at least amplifies an electric signal that is a weak electric charge obtained from the piezoelectric element 10 of the sensor unit 100, and a rod-shaped unit that guides the electric charge generated in the piezoelectric element 10 to the circuit board unit 21. It includes a conduction member 22, a covering member 23 that covers the circuit board portion 21, the conduction member 22, and the like, and an O-ring 24 that seals the circuit board portion 21 and the like.

回路基板部２１は、センサ部１００の圧電素子１０から得られる微弱な電荷を増幅するための回路を構成する電子部品などが実装されたプリント配線基板２１０を有する。プリント配線基板２１０における先端部には、伝導部材２２における後端部を電気的に接続するための第１の接続ピン２１ａと、接地用および位置決め用の第２の接続ピン２１ｂとが半田付けなどにより接続されている。また、プリント配線基板２１０における後端部には、伝送ケーブル８の先端部のコネクタ８ａを介して制御装置６と電気的に接続する第３の接続ピン２１ｃが３つ、半田付けなどにより接続されている。３つの第３の接続ピン２１ｃは、それぞれ、制御装置６からプリント配線基板２１０への電源電圧およびＧＮＤ電圧の供給、プリント配線基板２１０から制御装置６への出力電圧の供給に用いられる。 The circuit board unit 21 has a printed wiring board 210 on which electronic components and the like constituting a circuit for amplifying a weak electric charge obtained from the piezoelectric element 10 of the sensor unit 100 are mounted. A first connection pin 21a for electrically connecting the rear end portion of the conductive member 22 and a second connection pin 21b for grounding and positioning are soldered to the front end portion of the printed wiring board 210. Is connected by. Further, three third connection pins 21c that are electrically connected to the control device 6 via the connector 8a at the tip of the transmission cable 8 are connected to the rear end of the printed wiring board 210 by soldering or the like. ing. The three third connection pins 21c are used for supplying the power supply voltage and GND voltage from the control device 6 to the printed wiring board 210 and supplying the output voltage from the printed wiring board 210 to the control device 6, respectively.

伝導部材２２は、棒状（円柱状）の部材であり、先端部には、第２の電極部５５の突出部５５ａの先端部が挿入される挿入孔２２ａが形成されている。伝導部材２２における後端部は、回路基板部２１のプリント配線基板２１０に、導線を介して電気的に接続される。伝導部材２２の材質としては、真鍮及びベリリウム銅等を例示することができる。この場合、加工性およびコストの観点からは、真鍮が望ましい。これに対して、電気伝導性、高温強度、信頼性の観点からは、ベリリウム銅が望ましい。 The conducting member 22 is a rod-shaped (cylindrical) member, and an insertion hole 22a into which the tip of the protruding portion 55a of the second electrode portion 55 is inserted is formed at the tip portion. The rear end portion of the conduction member 22 is electrically connected to the printed wiring board 210 of the circuit board portion 21 via a conducting wire. Examples of the material of the conductive member 22 include brass and beryllium copper. In this case, brass is desirable from the viewpoint of workability and cost. On the other hand, beryllium copper is desirable from the viewpoint of electrical conductivity, high temperature strength, and reliability.

覆い部材２３は、伝導部材２２の外周を覆う伝導部材被覆部２３１と、回路基板部２１のプリント配線基板２１０の側面および下面を覆う基板被覆部２３２と、プリント配線基板２１０に接続された第３の接続ピン２１ｃの周囲を覆うとともに伝送ケーブル８の先端部のコネクタ８ａが嵌め込まれるコネクタ部２３３と、を有している。 The covering member 23 is connected to a conductive member covering portion 231 that covers the outer periphery of the conductive member 22, a substrate covering portion 232 that covers the side surfaces and the lower surface of the printed wiring board 210 of the circuit board portion 21, and a third printed wiring board 210. It has a connector portion 233 that covers the periphery of the connection pin 21c and into which the connector 8a at the tip of the transmission cable 8 is fitted.

伝導部材被覆部２３１は、中心線方向には、伝導部材２２における先端部を露出するように覆っており、先端側から後端側にかけて段階的に径が異なるように形成された外周面２４０が設けられている。外周面２４０は、先端側から後端側にかけて、第１の外周面２４１と、第１の外周面２４１の外径よりも大きな外径の第２の外周面２４２と、第２の外周面２４２の外径よりも大きな外径の第３の外周面２４３と、第３の外周面２４３の外径よりも大きな外径の第４の外周面２４４と、から構成される。第１の外周面２４１の径は、支持部材６５の第３の孔６５３の孔径よりも大きく、伝導部材被覆部２３１における先端部が、支持部材６５の第３の孔６５３を形成する周囲の壁にしまりばめで嵌合（圧入）される。第２の外周面２４２の径は、第２のハウジング３２の第２の孔３２２の孔径よりも小さく形成され、第３の外周面２４３の径は、第２のハウジング３２の第３の孔３２３の孔径よりも小さく形成されている。また、第４の外周面２４４の径は、第２のハウジング３２の第４の孔３２４の孔径よりも大きく、伝導部材被覆部２３１における後端部が、第２のハウジング３２の第４の孔３２４を形成する周囲の壁にしまりばめで嵌合（圧入）される。これらにより、伝導部材被覆部２３１は、少なくとも中心線方向の両端部が、それぞれ支持部材６５、第２のハウジング３２に接触することで支持されているので、劣悪な振動環境であっても、伝導部材２２に与える悪影響を抑制することができ、振動に起因して伝導部材２２の接続部の断線や接触不良等を回避することが可能になっている。 The conductive member covering portion 231 covers the leading end portion of the conductive member 22 so as to be exposed in the center line direction, and the outer peripheral surface 240 formed so as to have a stepwise different diameter from the front end side to the rear end side. It is provided. The outer peripheral surface 240 has a first outer peripheral surface 241 and a second outer peripheral surface 242 having an outer diameter larger than the outer diameter of the first outer peripheral surface 241 and a second outer peripheral surface 242 from the front end side to the rear end side. It is composed of a third outer peripheral surface 243 having an outer diameter larger than the outer diameter of the third outer peripheral surface 243 and a fourth outer peripheral surface 244 having an outer diameter larger than the outer diameter of the third outer peripheral surface 243. The diameter of the first outer peripheral surface 241 is larger than the diameter of the third hole 653 of the support member 65, and the tip portion of the conduction member covering portion 231 forms a peripheral wall forming the third hole 653 of the support member 65. It is fitted (press-fitted) with a tight fit. The diameter of the second outer peripheral surface 242 is formed to be smaller than the diameter of the hole 322 of the second hole 322 of the second housing 32, and the diameter of the third outer peripheral surface 243 is the diameter of the third hole 323 of the second housing 32. It is formed smaller than the hole diameter of. Further, the diameter of the fourth outer peripheral surface 244 is larger than the diameter of the hole 324 of the fourth hole 324 of the second housing 32, and the rear end portion of the conductive member covering portion 231 is the fourth hole of the second housing 32. It is fitted (press-fitted) into the surrounding wall forming the 324 by a tight fit. As a result, the conductive member covering portion 231 is supported by contacting at least both ends in the center line direction with the support member 65 and the second housing 32, respectively, so that conduction is possible even in a poor vibration environment. It is possible to suppress an adverse effect on the member 22, and it is possible to avoid disconnection of the connection portion of the conductive member 22 and poor contact due to vibration.

基板被覆部２３２は、基本的には円筒状の部位であり、その側面には、プリント配線基板２１０を内部に設置するための矩形の開口部２３２ａが設けられている。また、基板被覆部２３２における後端側には、ハウジング３０内およびプリント配線基板２１０の設置部を密封するためのＯリング２４用のリング溝２３２ｂが形成されている。 The substrate covering portion 232 is basically a cylindrical portion, and a rectangular opening 232a for installing the printed wiring board 210 inside is provided on the side surface thereof. Further, a ring groove 232b for an O-ring 24 for sealing the inside of the housing 30 and the installation portion of the printed wiring board 210 is formed on the rear end side of the substrate covering portion 232.

コネクタ部２３３は、基板被覆部２３２における後端側の端面２３２ｃから突出し、プリント配線基板２１０に接続された３つの第３の接続ピン２１ｃの周囲を覆うように形成された薄肉の部位である。コネクタ部２３３における後端部は開口しており、内部に伝送ケーブル８の先端部に設けられたコネクタ８ａを受け入れることが可能になっている。また、コネクタ部２３３における後端側には、内部と外部とを連通する孔２３３ａが形成されており、伝送ケーブル８のコネクタ８ａに設けられたフックがこの孔２３３ａに引っ掛ることで、伝送ケーブル８のコネクタ８ａがコネクタ部２３３から脱落することが抑制される。 The connector portion 233 is a thin portion formed so as to project from the rear end side end surface 232c of the substrate covering portion 232 and cover the periphery of the three third connection pins 21c connected to the printed wiring board 210. The rear end portion of the connector portion 233 is open so that the connector 8a provided at the tip end portion of the transmission cable 8 can be received inside. Further, a hole 233a for communicating the inside and the outside is formed on the rear end side of the connector portion 233, and a hook provided on the connector 8a of the transmission cable 8 is hooked on the hole 233a to hook the transmission cable. The connector 8a of 8 is prevented from falling off from the connector portion 233.

以上のように構成された覆い部材２３は、樹脂などの絶縁性を有する材料にて成形されている。また、覆い部材２３は、伝導部材２２、第１の接続ピン２１ａ、第２の接続ピン２１ｂおよび３つの第３の接続ピン２１ｃとともに一体成形されている。より具体的には、覆い部材２３は、これら伝導部材２２、第１の接続ピン２１ａ、第２の接続ピン２１ｂおよび３つの第３の接続ピン２１ｃをセットした金型に加熱した樹脂が押し込まれることで成形される。 The covering member 23 configured as described above is molded of an insulating material such as resin. Further, the covering member 23 is integrally molded together with the conductive member 22, the first connecting pin 21a, the second connecting pin 21b, and the three third connecting pins 21c. More specifically, in the covering member 23, the heated resin is pushed into a mold in which the conductive member 22, the first connecting pin 21a, the second connecting pin 21b, and the three third connecting pins 21c are set. It is molded by.

信号処理部２００をユニット化するにあたっては、成形された覆い部材２３の開口部２３２ａから、回路基板部２１のプリント配線基板２１０を挿入し、基板被覆部２３２の中央部に設置する。プリント配線基板２１０を設置する際、板厚方向に貫通されたスルーホールに、第１の接続ピン２１ａ、第２の接続ピン２１ｂおよび３つの第３の接続ピン２１ｃの先端を通し、半田付けする。その後、第１の接続ピン２１ａと伝導部材２２とを導線を用いて接続する。また、覆い部材２３の基板被覆部２３２のリング溝２３２ｂにＯリング２４を装着する。Ｏリング２４は、フッ素系ゴムからなる周知のＯ状のリングである。 When the signal processing unit 200 is unitized, the printed wiring board 210 of the circuit board unit 21 is inserted from the opening 232a of the molded covering member 23 and installed in the central portion of the substrate covering portion 232. When the printed wiring board 210 is installed, the tips of the first connection pin 21a, the second connection pin 21b, and the three third connection pins 21c are passed through the through holes penetrated in the plate thickness direction and soldered. .. After that, the first connecting pin 21a and the conducting member 22 are connected by using a conducting wire. Further, the O-ring 24 is mounted in the ring groove 232b of the substrate covering portion 232 of the covering member 23. The O-ring 24 is a well-known O-ring made of fluorine-based rubber.

（保持部材）
次に、保持部材３００について説明する。
保持部材３００は、薄肉円筒状の部材であり、後端部に内周面から内側に突出した突出部３００ａが設けられている。保持部材３００は、第２のハウジング３２に装着された後、外部から、第５の外周面３３５に設けられた凹部３３５ａに対応する部位が加圧されることでかしめられる。これにより、保持部材３００は、ハウジング３０に対して移動し難くなり、信号処理部２００がハウジング３０に対して移動することを抑制する。 (Holding member)
Next, the holding member 300 will be described.
The holding member 300 is a thin-walled cylindrical member, and is provided with a protruding portion 300a protruding inward from the inner peripheral surface at the rear end portion. After the holding member 300 is mounted on the second housing 32, the holding member 300 is crimped from the outside by applying pressure to a portion corresponding to the recess 335a provided on the fifth outer peripheral surface 335. This makes it difficult for the holding member 300 to move with respect to the housing 30, and prevents the signal processing unit 200 from moving with respect to the housing 30.

（圧力検出装置における電気的な接続構造）
次に、上述した圧力検出装置５における電気的な接続構造について説明する。
先ず、圧電素子１０における先端側の端面は、金属製の第１の電極部５０およびダイアフラムヘッド４０を介して、金属製のハウジング３０と電気的に接続される。 (Electrical connection structure in pressure detector)
Next, the electrical connection structure in the pressure detection device 5 described above will be described.
First, the end face of the piezoelectric element 10 on the distal end side is electrically connected to the metal housing 30 via the first metal electrode portion 50 and the diaphragm head 40.

これに対し、圧電素子１０における後端側の端面は、金属製の第２の電極部５５と電気的に接続され、第２の電極部５５は、突出部５５ａを介して金属製のコイルスプリング７０と電気的に接続される。また、コイルスプリング７０は、金属製の伝導部材２２と電気的に接続され、伝導部材２２は、プリント配線基板２１０と電気的に接続される。他方、第２の電極部５５の突出部５５ａの外径は支持部材６５の第１の孔６５１の孔径よりも小さく、伝導部材２２における先端部の外径は支持部材６５の第２の孔６５２の孔径よりも小さい。つまり、第２の電極部５５、コイルスプリング７０および伝導部材２２は、支持部材６５と電気的に接続されていない。それゆえ、第２の電極部５５からコイルスプリング７０および伝導部材２２を介してプリント配線基板２１０へと至る電荷信号の伝送経路は、それぞれが絶縁体で構成された、絶縁リング６０および覆い部材２３によって、金属製のハウジング３０と電気的に絶縁される。 On the other hand, the rear end surface of the piezoelectric element 10 is electrically connected to the second metal electrode portion 55, and the second electrode portion 55 is connected to the metal coil spring via the protruding portion 55a. It is electrically connected to the 70. Further, the coil spring 70 is electrically connected to the metal conductive member 22, and the conductive member 22 is electrically connected to the printed wiring board 210. On the other hand, the outer diameter of the protruding portion 55a of the second electrode portion 55 is smaller than the hole diameter of the first hole 651 of the support member 65, and the outer diameter of the tip portion of the conduction member 22 is the second hole 652 of the support member 65. It is smaller than the hole diameter of. That is, the second electrode portion 55, the coil spring 70, and the conduction member 22 are not electrically connected to the support member 65. Therefore, the transmission path of the charge signal from the second electrode portion 55 to the printed wiring board 210 via the coil spring 70 and the conductive member 22 is an insulating ring 60 and a covering member 23, each of which is composed of an insulator. Is electrically insulated from the metal housing 30.

（圧力検出装置の取り付け）
以上のように構成された圧力検出装置５をシリンダヘッド４に装着する際には、センサ部１００のダイアフラムヘッド４０の方から先にシリンダヘッド４に形成された連通孔４ａに挿入していき、ハウジング３０の第２のハウジング３２に形成された雄ねじ３３２ａをシリンダヘッド４の連通孔４ａに形成された雌ねじ４ｅにねじ込む。
圧力検出装置５をシリンダヘッド４に装着することにより、ハウジング３０は、金属製のシリンダヘッド４と電気的に接続される。このシリンダヘッド４は、電気的に接地された状態にあるため、圧力検出装置５では、ハウジング３０を介して、圧電素子１０における先端部が接地される。このとき、圧力検出装置５の先端側では、ダイアフラムヘッド４０における筒状部４１に取り付けられた抑制リング８０の外周面が、空隙を介して、シリンダヘッド４に形成された連通孔４ａの内周面に対峙する。すなわち、抑制リング８０と連通孔４ａとが、非接触な状態に設定される。また、圧電素子１０とハウジング３０とが直接接触しないよう、圧電素子１０の側面とハウジング３０の内壁面との間には空隙が設けられる。 (Installation of pressure detector)
When the pressure detecting device 5 configured as described above is mounted on the cylinder head 4, the diaphragm head 40 of the sensor unit 100 is inserted into the communication hole 4a formed in the cylinder head 4 first. The male screw 332a formed in the second housing 32 of the housing 30 is screwed into the female screw 4e formed in the communication hole 4a of the cylinder head 4.
By mounting the pressure detection device 5 on the cylinder head 4, the housing 30 is electrically connected to the metal cylinder head 4. Since the cylinder head 4 is in a state of being electrically grounded, in the pressure detecting device 5, the tip portion of the piezoelectric element 10 is grounded via the housing 30. At this time, on the tip side of the pressure detection device 5, the outer peripheral surface of the suppression ring 80 attached to the tubular portion 41 of the diaphragm head 40 is the inner circumference of the communication hole 4a formed in the cylinder head 4 through the gap. Face the face. That is, the suppression ring 80 and the communication hole 4a are set in a non-contact state. Further, a gap is provided between the side surface of the piezoelectric element 10 and the inner wall surface of the housing 30 so that the piezoelectric element 10 and the housing 30 do not come into direct contact with each other.

［シール部材］
次に、シール部材７について説明する。
シール部材７は、シリンダヘッド４における連通孔４ａを形成する周囲の壁の圧力検出装置５の締め付け方向の端面と、圧力検出装置５のハウジング３０の第４の外周面３３４が設けられた円柱状の部位の先端側の端面との間に配置され、シリンダヘッド４と圧力検出装置５との間をシールする第１のシール部材７１を有している。また、シール部材７は、シリンダヘッド４の連通孔４ａの傾斜部４ｃと、圧力検出装置５のハウジング３０の第１のハウジング３１の傾斜面３１５ａとの間に配置され、シリンダヘッド４と圧力検出装置５との間をシールする第２のシール部材７２を有している。 [Seal member]
Next, the seal member 7 will be described.
The seal member 7 is a columnar surface provided with an end surface in the tightening direction of the pressure detection device 5 on the surrounding wall forming the communication hole 4a in the cylinder head 4 and a fourth outer peripheral surface 334 of the housing 30 of the pressure detection device 5. It has a first sealing member 71 which is arranged between the end face on the tip end side of the portion and seals between the cylinder head 4 and the pressure detecting device 5. Further, the seal member 7 is arranged between the inclined portion 4c of the communication hole 4a of the cylinder head 4 and the inclined surface 315a of the first housing 31 of the housing 30 of the pressure detection device 5, and is arranged between the cylinder head 4 and the pressure detection. It has a second sealing member 72 that seals between the device 5 and the device 5.

第１のシール部材７１は、銅、ステンレス、アルミなどの金属板を打ち抜いて成形されたメタルガスケットであることを例示することができる。断面形状はＳ字状、または略矩形に形成されているとよい。第１のシール部材７１は、圧力検出装置５がシリンダヘッド４に締め付けられる際に、締め付け方向の力を受けて、締め付け方向の長さが短くなるように変形し、燃焼室Ｃ内の気密性を高める。すなわち、圧力検出装置５がシリンダヘッド４にねじ込まれることで、第１のシール部材７１とシリンダヘッド４との間に生じる接触圧力、および第１のシール部材７１と圧力検出装置５のハウジング３０との間に生じる接触圧力が高まる。これにより、第１のシール部材７１とシリンダヘッド４との間、および第１のシール部材７１と圧力検出装置５のハウジング３０との間から燃焼ガスが漏れることが抑制される。 It can be exemplified that the first sealing member 71 is a metal gasket formed by punching a metal plate such as copper, stainless steel, or aluminum. The cross-sectional shape is preferably S-shaped or substantially rectangular. When the pressure detection device 5 is tightened to the cylinder head 4, the first seal member 71 is deformed so as to shorten the length in the tightening direction by receiving a force in the tightening direction, and the airtightness in the combustion chamber C is reduced. To increase. That is, the contact pressure generated between the first seal member 71 and the cylinder head 4 when the pressure detection device 5 is screwed into the cylinder head 4, and the housing 30 between the first seal member 71 and the pressure detection device 5 The contact pressure generated between the two increases. As a result, leakage of combustion gas between the first seal member 71 and the cylinder head 4 and between the first seal member 71 and the housing 30 of the pressure detection device 5 is suppressed.

第２のシール部材７２は、材質がフッ素ゴム（ＦＫＭ）の、断面が円形であるリング状のＯリングであることを例示することができる。第２のシール部材７２は、圧力検出装置５がシリンダヘッド４に締め付けられる際に、シリンダヘッド４の連通孔４ａの傾斜部４ｃと、ハウジング３０の第１のハウジング３１の傾斜面３１５ａとにより、締め付け方向とは交差する方向の力を受けて変形し、燃焼室Ｃ内の気密性を高める。すなわち、圧力検出装置５がシリンダヘッド４にねじ込まれることで、第２のシール部材７２とシリンダヘッド４の連通孔４ａの傾斜部４ｃとの間に生じる接触圧力、および第２のシール部材７２とハウジング３０の第１のハウジング３１の傾斜面３１５ａとの間に生じる接触圧力が高まる。これにより、第２のシール部材７２とシリンダヘッド４との間、および第２のシール部材７２と圧力検出装置５のハウジング３０との間から燃焼ガスが漏れることが抑制される。 It can be exemplified that the second sealing member 72 is a ring-shaped O-ring made of fluororubber (FKM) and having a circular cross section. When the pressure detection device 5 is tightened to the cylinder head 4, the second seal member 72 is formed by the inclined portion 4c of the communication hole 4a of the cylinder head 4 and the inclined surface 315a of the first housing 31 of the housing 30. It deforms by receiving a force in the direction intersecting the tightening direction, and enhances the airtightness in the combustion chamber C. That is, when the pressure detection device 5 is screwed into the cylinder head 4, the contact pressure generated between the second seal member 72 and the inclined portion 4c of the communication hole 4a of the cylinder head 4 and the second seal member 72 The contact pressure generated between the first housing 31 of the housing 30 and the inclined surface 315a of the first housing 31 increases. As a result, leakage of combustion gas between the second seal member 72 and the cylinder head 4 and between the second seal member 72 and the housing 30 of the pressure detection device 5 is suppressed.

［圧力検出装置の製造方法］
次に、圧力検出装置５の製造方法について説明する。
まず、ダイアフラムヘッド４０の先端段差部４１４と抑制リング８０の先端面８１とが接触するまで、ダイアフラムヘッド４０と抑制リング８０とを嵌合（圧入）する。続いて、抑制リング８０が装着されたダイアフラムヘッド４０の後端段差部４１５と第１のハウジング３１の端面３１ａとが接触するまで、第１のハウジング３１とダイアフラムヘッド４０とを嵌合（圧入）する。その後、第１のハウジング３１の端面３１ａとダイアフラムヘッド４０の後端段差部４１５とが接触している部位に、中心線方向に交差する方向（例えば中心線方向に直交する方向）からレーザビームを照射して、第１のハウジング３１とダイアフラムヘッド４０とを溶接（接合）する。 [Manufacturing method of pressure detector]
Next, a method of manufacturing the pressure detection device 5 will be described.
First, the diaphragm head 40 and the suppression ring 80 are fitted (press-fitted) until the tip step portion 414 of the diaphragm head 40 and the tip surface 81 of the suppression ring 80 come into contact with each other. Subsequently, the first housing 31 and the diaphragm head 40 are fitted (press-fitted) until the rear end step portion 415 of the diaphragm head 40 to which the restraining ring 80 is mounted and the end surface 31a of the first housing 31 come into contact with each other. To do. After that, a laser beam is applied to a portion where the end surface 31a of the first housing 31 and the rear end step portion 415 of the diaphragm head 40 are in contact with each other from a direction intersecting the center line direction (for example, a direction orthogonal to the center line direction). By irradiating, the first housing 31 and the diaphragm head 40 are welded (joined).

次いで、第１のハウジング３１における後端側の開口部から、第１の電極部５０および圧電素子１０を挿入する。その後、第２の電極部５５の突出部５５ａの先端部にコイルスプリング７０を装着するとともに、第２の電極部５５の突出部５５ａに絶縁リング６０を挿入した状態のものを、第１のハウジング３１における後端側の開口部から挿入する。それから、支持部材６５を第１のハウジング３１における後端側の開口部から挿入する。そして、第１のハウジング３１内の圧電素子１０に、予め決められた大きさの荷重（予荷重）を作用させた状態で、支持部材６５と第１のハウジング３１とを固定する。 Next, the first electrode portion 50 and the piezoelectric element 10 are inserted through the opening on the rear end side of the first housing 31. After that, the coil spring 70 is attached to the tip of the protruding portion 55a of the second electrode portion 55, and the insulating ring 60 is inserted into the protruding portion 55a of the second electrode portion 55. It is inserted through the opening on the rear end side in 31. Then, the support member 65 is inserted through the opening on the rear end side of the first housing 31. Then, the support member 65 and the first housing 31 are fixed in a state where a load (preload) of a predetermined size is applied to the piezoelectric element 10 in the first housing 31.

支持部材６５と第１のハウジング３１とを固定した後、第１のハウジング３１の突出部３１５の垂直面３１５ｂと第２のハウジング３２における先端側の端面とが接触するまで、第１のハウジング３１と第２のハウジング３２とを嵌合（圧入）する。その後、第１のハウジング３１の垂直面３１５ｂと第２のハウジング３２の端面とが接触している部位に、中心線方向に交差する方向（例えば中心線方向に直交する方向）からレーザビームを照射して、第１のハウジング３１と第２のハウジング３２とを溶接する。 After fixing the support member 65 and the first housing 31, the first housing 31 is in contact with the vertical surface 315b of the protrusion 315 of the first housing 31 and the end surface on the distal end side of the second housing 32. And the second housing 32 are fitted (press-fitted). After that, the portion where the vertical surface 315b of the first housing 31 and the end surface of the second housing 32 are in contact with each other is irradiated with a laser beam from a direction intersecting the center line direction (for example, a direction orthogonal to the center line direction). Then, the first housing 31 and the second housing 32 are welded together.

次に、信号処理部２００の覆い部材２３の基板被覆部２３２における先端側の端面が第２のハウジング３２の突当面３４０に突き当たるまで、信号処理部２００を、第２のハウジング３２における後端側の開口部から挿入する。その際、信号処理部２００の伝導部材２２の挿入孔２２ａに、第２の電極部５５の突出部５５ａに装着されたコイルスプリング７０が入り込むとともに、第２のハウジング３２の突当面３４０に形成されたピン用凹部３４０ａに、プリント配線基板２１０に接続された第２の接続ピン２１ｂが入り込むように、信号処理部２００を挿入する。 Next, the signal processing unit 200 is kept on the rear end side of the second housing 32 until the end surface on the front end side of the substrate covering portion 232 of the covering member 23 of the signal processing unit 200 abuts on the abutting surface 340 of the second housing 32. Insert through the opening of. At that time, the coil spring 70 mounted on the protruding portion 55a of the second electrode portion 55 is inserted into the insertion hole 22a of the conduction member 22 of the signal processing unit 200, and is formed on the abutting surface 340 of the second housing 32. The signal processing unit 200 is inserted so that the second connection pin 21b connected to the printed wiring board 210 is inserted into the pin recess 340a.

その後、信号処理部２００の基板被覆部２３２の端面２３２ｃに保持部材３００の突出部３００ａが突き当たるまで、保持部材３００を、後端側から信号処理部２００に嵌め込んでいく。信号処理部２００の端面２３２ｃと保持部材３００の突出部３００ａとが接触した状態で、保持部材３００における、第２のハウジング３２の第５の外周面３３５の凹部３３５ａに対応する部位が加圧されることで、保持部材３００が第２のハウジング３２にかしめられる。これにより、保持部材３００がハウジング３０に対して移動し難くなり、信号処理部２００がハウジング３０に対して移動し難くなる。 After that, the holding member 300 is fitted into the signal processing unit 200 from the rear end side until the protruding portion 300a of the holding member 300 abuts on the end surface 232c of the substrate covering portion 232 of the signal processing unit 200. In a state where the end surface 232c of the signal processing unit 200 and the protruding portion 300a of the holding member 300 are in contact with each other, the portion of the holding member 300 corresponding to the recess 335a of the fifth outer peripheral surface 335 of the second housing 32 is pressurized. As a result, the holding member 300 is crimped to the second housing 32. As a result, the holding member 300 becomes difficult to move with respect to the housing 30, and the signal processing unit 200 becomes difficult to move with respect to the housing 30.

［圧力検出装置による圧力検出動作］
では、圧力検出装置５による内燃機関１の圧力検出動作について説明を行う。
内燃機関１が動作しているとき、ダイアフラムヘッド４０における閉塞部４２の先端側（表面）に、燃焼室Ｃ内で発生した燃焼ガスによる圧力（燃焼圧）が付与される。ダイアフラムヘッド４０では、表面凹部４２１側で受けた圧力が裏面側の裏面凸部４２２に伝達され、第１の電極部５０と第２の電極部５５とによって挟まれた圧電素子１０に作用することにより、この圧電素子１０に、燃焼圧に応じた電荷が生じる。そして、圧電素子１０に生じた電荷は、第２の電極部５５、コイルスプリング７０、伝導部材２２を介して回路基板部２１に供給される。回路基板部２１に供給された電荷は、回路基板部２１にて増幅処理がなされた後、その電荷に応じた電圧が、回路基板部２１に接続された第３の接続ピン２１ｃ、伝送ケーブル８を介して制御装置６に供給される。 [Pressure detection operation by pressure detection device]
Then, the pressure detection operation of the internal combustion engine 1 by the pressure detection device 5 will be described.
When the internal combustion engine 1 is operating, the pressure (combustion pressure) due to the combustion gas generated in the combustion chamber C is applied to the tip end side (surface) of the closed portion 42 in the diaphragm head 40. In the diaphragm head 40, the pressure received on the front surface concave portion 421 side is transmitted to the back surface convex portion 422 on the back surface side, and acts on the piezoelectric element 10 sandwiched between the first electrode portion 50 and the second electrode portion 55. As a result, the piezoelectric element 10 is charged according to the combustion pressure. Then, the electric charge generated in the piezoelectric element 10 is supplied to the circuit board portion 21 via the second electrode portion 55, the coil spring 70, and the conduction member 22. The electric charge supplied to the circuit board unit 21 is amplified by the circuit board unit 21, and then a voltage corresponding to the electric charge is applied to the third connection pin 21c and the transmission cable 8 connected to the circuit board unit 21. It is supplied to the control device 6 via.

［燃焼ガスの挙動と圧力検出装置との関係］
ここで、上述した圧力検出動作における、燃焼ガスの挙動と圧力検出装置５との関係について説明を行う。 [Relationship between combustion gas behavior and pressure detector]
Here, the relationship between the behavior of the combustion gas and the pressure detection device 5 in the pressure detection operation described above will be described.

まず、内燃機関１の燃焼室Ｃ内で、燃料を燃焼させることに伴って生じた燃焼ガスが熱膨張し、燃焼圧が発生する。そして、燃焼室Ｃ内で発生した燃焼ガスが、圧力検出装置５のダイアフラムヘッド４０の閉塞部４２に作用する。これに伴い、上述した手順にて、圧力検出動作が行われる。 First, in the combustion chamber C of the internal combustion engine 1, the combustion gas generated by burning the fuel thermally expands, and a combustion pressure is generated. Then, the combustion gas generated in the combustion chamber C acts on the closing portion 42 of the diaphragm head 40 of the pressure detecting device 5. Along with this, the pressure detection operation is performed according to the procedure described above.

一方、燃焼室Ｃ内で発生した燃焼ガスは、圧力検出装置５の先端側すなわちダイアフラムヘッド４０側から、シリンダヘッド４に設けられた連通孔４ａの内周面と、圧力検出装置５（ダイアフラムヘッド４０、抑制リング８０およびハウジング３０）の外周面との間に存在するエアギャップに進入し、後端側へと向かう。 On the other hand, the combustion gas generated in the combustion chamber C is discharged from the tip side of the pressure detecting device 5, that is, the diaphragm head 40 side, to the inner peripheral surface of the communication hole 4a provided in the cylinder head 4, and the pressure detecting device 5 (diaphragm head). 40, enters the air gap existing between the restraining ring 80 and the outer peripheral surface of the housing 30), and heads toward the rear end side.

このとき、圧力検出装置５では、ダイアフラムヘッド４０が、高温の燃焼ガスにさらされることで加熱され、熱膨張する。熱膨張に伴ってダイアフラムヘッド４０における筒状部４１が軸方向に伸びると、ダイアフラムヘッド４０、第１の電極部５０および第２の電極部５５等を介して圧電素子１０に付与している予荷重が減少する。そして、この熱膨張が解消する前すなわちダイアフラムヘッド４０が収縮する前に、燃焼室Ｃにて次の燃焼が開始されると、圧力検出装置５からの出力値は、予荷重が減少している分、本来の出力値よりも低下してしまうことになる。 At this time, in the pressure detection device 5, the diaphragm head 40 is heated by being exposed to the high-temperature combustion gas and thermally expands. When the tubular portion 41 of the diaphragm head 40 extends in the axial direction due to thermal expansion, it is applied to the piezoelectric element 10 via the diaphragm head 40, the first electrode portion 50, the second electrode portion 55, and the like. The load is reduced. Then, when the next combustion is started in the combustion chamber C before the thermal expansion is eliminated, that is, before the diaphragm head 40 contracts, the preload of the output value from the pressure detection device 5 is reduced. By that amount, it will be lower than the original output value.

ここで、本実施の形態では、圧力検出装置５に設けられたダイアフラムヘッド４０における筒状部４１の外側に、ダイアフラムヘッド４０よりも熱伝導率が低い抑制リング８０を設けている。これにより、圧力検出装置５の先端側から、シリンダヘッド４に設けられた連通孔４ａの内周面と、圧力検出装置５の外周面との間に存在するエアギャップに進入してきた燃焼ガスの熱は、抑制リング８０を設けない場合と比較して、ダイアフラムヘッド４０における筒状部４１に伝達されにくくなる（熱の伝達が抑制される）。これに伴い、燃焼ガスの熱に起因する、ダイアフラムヘッド４０における筒状部４１の熱膨張が生じにくくなる。その結果、ダイアフラムヘッド４０等を用いて圧電素子１０に付与する予荷重の変動、ひいては、圧力検出装置５からの出力値の変動が生じにくくなる。 Here, in the present embodiment, the suppression ring 80 having a lower thermal conductivity than the diaphragm head 40 is provided on the outside of the tubular portion 41 of the diaphragm head 40 provided in the pressure detection device 5. As a result, the combustion gas that has entered the air gap existing between the inner peripheral surface of the communication hole 4a provided in the cylinder head 4 and the outer peripheral surface of the pressure detecting device 5 from the tip side of the pressure detecting device 5 Heat is less likely to be transferred to the tubular portion 41 of the diaphragm head 40 (heat transfer is suppressed) as compared with the case where the suppression ring 80 is not provided. Along with this, thermal expansion of the tubular portion 41 in the diaphragm head 40 due to the heat of the combustion gas is less likely to occur. As a result, fluctuations in the preload applied to the piezoelectric element 10 by using the diaphragm head 40 or the like, and by extension, fluctuations in the output value from the pressure detection device 5 are less likely to occur.

図８は、圧力検出装置５からの出力値の時間経過を示した図である。ここで、図８（ａ）は、抑制リング８０を設けないことでダイアフラムヘッド４０の筒状部４１の外周面をすべて露出させた圧力検出装置５（以下では、従来の圧力検出装置５という）の場合を、図８（ｂ）は、抑制リング８０を設けた圧力検出装置５（以下では、今回の圧力検出装置５という）の場合を、それぞれ例示している。なお、図８（ａ）、（ｂ）のそれぞれにおいて、横軸は時間であり、縦軸は圧力検出装置５からの出力値である。 FIG. 8 is a diagram showing the passage of time of the output value from the pressure detection device 5. Here, FIG. 8A shows a pressure detection device 5 (hereinafter referred to as a conventional pressure detection device 5) in which the outer peripheral surface of the tubular portion 41 of the diaphragm head 40 is completely exposed by not providing the suppression ring 80. 8 (b) illustrates the case of the pressure detection device 5 provided with the suppression ring 80 (hereinafter, referred to as the pressure detection device 5 this time). In each of FIGS. 8A and 8B, the horizontal axis is time and the vertical axis is the output value from the pressure detection device 5.

従来の圧力検出装置５の場合、ダイアフラムヘッド４０における筒状部４１の熱膨張が１熱サイクルでは解消しきれなくなり、時間の経過とともに予荷重が減少していく。その結果、図８（ａ）に示したように、時間の経過とともに出力値の基準値（非燃焼時の出力値）が徐々に低下していき、例えば各熱サイクルにおける燃焼圧が同じであったとしても、得られる出力値のピーク値は徐々に低下していくこととなる。 In the case of the conventional pressure detection device 5, the thermal expansion of the tubular portion 41 in the diaphragm head 40 cannot be completely eliminated in one thermal cycle, and the preload decreases with the passage of time. As a result, as shown in FIG. 8A, the reference value of the output value (output value at the time of non-combustion) gradually decreases with the passage of time, and for example, the combustion pressure in each thermal cycle is the same. Even so, the peak value of the obtained output value will gradually decrease.

一方、今回の圧力検出装置５の場合、ダイアフラムヘッド４０における筒状部４１の熱膨張が生じにくくなる分、予荷重の変動も生じにくくなる。その結果、図８（ｂ）に示したように、時間の経過に関わりなく出力値の基準値（非燃焼時の出力値）が安定するようになり、各熱サイクルにおける出力値のピーク値のずれも発生しにくくなる。 On the other hand, in the case of the pressure detecting device 5 this time, the fluctuation of the preload is less likely to occur because the thermal expansion of the tubular portion 41 in the diaphragm head 40 is less likely to occur. As a result, as shown in FIG. 8B, the reference value of the output value (output value at the time of non-combustion) becomes stable regardless of the passage of time, and the peak value of the output value in each thermal cycle becomes stable. Misalignment is less likely to occur.

なお、発明者の実験によれば、燃焼室Ｃでの燃焼時における圧力検出装置５の先端側（ダイアフラムヘッド４０周辺）の温度は、２５０〜３００℃程度になることが判明している。ここで、抑制リング８０を構成する材料として、ＰＴＦＥ（polytetrafluoroethylene）等の樹脂を用いた場合、上記温度領域において樹脂の劣化や分解が生じ、抑制リング８０としての機能を果たさなくなってしまうおそれがある。
これに対し、本実施の形態では、上記温度領域において劣化や分解が生じ難い無機材料（セラミックス材料）を用いていることから、このような問題は生じ難いといえる。 According to the inventor's experiment, it has been found that the temperature of the tip side (around the diaphragm head 40) of the pressure detecting device 5 at the time of combustion in the combustion chamber C is about 250 to 300 ° C. Here, when a resin such as PTFE (polytetrafluoroethylene) is used as the material constituting the suppression ring 80, the resin may deteriorate or decompose in the above temperature range and may not function as the suppression ring 80. ..
On the other hand, in the present embodiment, since an inorganic material (ceramic material) that is unlikely to deteriorate or decompose in the above temperature range is used, it can be said that such a problem is unlikely to occur.

［その他］
なお、本実施の形態では、圧力検出装置５で用いる抑制リング８０として、アルミナを用いていたが、これに限られるものではなく、ジルコニア（安定化ジルコニアを含む）やイットリア等の各種酸化物、窒化アルミニウム等の窒化物、さらには炭化珪素等の炭化物等を用いてもかまわない。
また、本実施の形態では、圧力検出装置５で用いる抑制リング８０として、絶縁体（アルミナセラミックス）を用いていたが、ダイアフラムヘッド４０との間の熱伝導率の関係を満たすものであれば、半導体あるいは導体であってもかまわない。
さらに、本実施の形態では、圧力検出装置５で用いる抑制リング８０を構成する無機材料として、セラミックス（多結晶体）を用いていたが、例えばガラスであってもかまわない。 [Other]
In the present embodiment, alumina is used as the suppression ring 80 used in the pressure detection device 5, but the present invention is not limited to this, and various oxides such as zirconia (including stabilized zirconia) and yttria, etc. A nitride such as aluminum nitride, or a carbide such as silicon carbide may be used.
Further, in the present embodiment, an insulator (alumina ceramics) is used as the suppression ring 80 used in the pressure detection device 5, but if the relationship of thermal conductivity with the diaphragm head 40 is satisfied, it is sufficient. It may be a semiconductor or a conductor.
Further, in the present embodiment, ceramics (polycrystal) is used as the inorganic material constituting the suppression ring 80 used in the pressure detection device 5, but glass may be used, for example.

また、本実施の形態では、圧力検出装置５で用いる抑制リング８０を、ダイアフラムヘッド４０の外周面における後端側に設けていたが、これに限られるものではなく、例えばハウジング３０に設けてもかまわない。抑制リング８０をハウジング３０に設ける場合は、抑制リング８０をダイアフラムヘッド４０に近い、ハウジング３０の先端側に設けることが好ましい。この構成を採用した場合には、抑制リング８０により、ハウジング３０の熱膨張が生じにくくなり、圧力検出装置５の予荷重の変動も生じにくくなる。
さらに、本実施の形態では、圧力検出装置５における信号発生部として、圧電素子１０を用いた場合を例として説明を行ったが、これに限られるものではなく、例えばひずみゲージや離間した電極等を用いてもかまわない。
さらにまた、本実施の形態では、圧力検出装置５による圧力の検出対象を内燃機関１としていたが、これに限られるものではなく、内燃機関１以外であってもかまわない。 Further, in the present embodiment, the suppression ring 80 used in the pressure detection device 5 is provided on the rear end side of the outer peripheral surface of the diaphragm head 40, but the present invention is not limited to this, and for example, the suppression ring 80 may be provided in the housing 30. It doesn't matter. When the restraining ring 80 is provided in the housing 30, it is preferable that the restraining ring 80 is provided on the tip end side of the housing 30 close to the diaphragm head 40. When this configuration is adopted, the suppression ring 80 makes it difficult for the housing 30 to expand thermally, and makes it difficult for the preload of the pressure detection device 5 to fluctuate.
Further, in the present embodiment, the case where the piezoelectric element 10 is used as the signal generation unit in the pressure detection device 5 has been described as an example, but the present invention is not limited to this, and for example, a strain gauge, a separated electrode, etc. You may use.
Furthermore, in the present embodiment, the pressure detection target by the pressure detecting device 5 is the internal combustion engine 1, but the present invention is not limited to this, and may be other than the internal combustion engine 1.

１…内燃機関、２…シリンダブロック、３…ピストン、４…シリンダヘッド、５…圧力検出装置、６…制御装置、７…シール部材、８…伝送ケーブル、１０…圧電素子、２１…回路基板部、２２…伝導部材、２３…覆い部材、２４…Ｏリング、３０…ハウジング、４０…ダイアフラムヘッド、５０…第１の電極部、５５…第２の電極部、６０…絶縁リング、６５…支持部材、７０…コイルスプリング、８０…抑制リング、１００…センサ部、２００…信号処理部、３００…保持部材 1 ... Internal combustion engine, 2 ... Cylinder block, 3 ... Piston, 4 ... Cylinder head, 5 ... Pressure detector, 6 ... Control device, 7 ... Seal member, 8 ... Transmission cable, 10 ... Piezoelectric element, 21 ... Circuit board , 22 ... Conduction member, 23 ... Covering member, 24 ... O ring, 30 ... Housing, 40 ... Diaphragm head, 50 ... First electrode part, 55 ... Second electrode part, 60 ... Insulation ring, 65 ... Support member , 70 ... Coil spring, 80 ... Suppression ring, 100 ... Sensor unit, 200 ... Signal processing unit, 300 ... Holding member

Claims (3)

筒状の胴体部と、
筒状の筒状部と当該筒状部の一端部側で当該筒状部を塞ぐ閉塞部とを有し、当該筒状部の他端部側が前記胴体部の一端部側に設けられるとともに当該閉塞部が外部から圧力を受ける受圧部と、
前記胴体部の内側に設けられ、前記受圧部が受けた圧力に応じた信号を発生する信号発生部と、
前記受圧部よりも熱伝導率が低い無機材料で構成され、前記筒状部の外側に取り付けられる環状の環状部材と
を含む圧力検出装置。 With a tubular body
It has a tubular tubular portion and a closing portion that closes the tubular portion on one end side of the tubular portion, and the other end side of the tubular portion is provided on one end side of the body portion and the said The pressure receiving part where the closed part receives pressure from the outside and the pressure receiving part
A signal generating unit provided inside the body portion and generating a signal according to the pressure received by the pressure receiving unit, and a signal generating unit.
A pressure detecting device including an annular member made of an inorganic material having a thermal conductivity lower than that of the pressure receiving portion and attached to the outside of the tubular portion. 前記環状部材における一端部側の面が前記受圧部に設けられた突き当て面に対向して配置され、当該環状部材における他端部側の面が前記胴体部に設けられた他の突き当て面に対向して配置されること
を特徴とする請求項１記載の圧力検出装置。 The surface on the one end side of the annular member is arranged to face the abutting surface provided on the pressure receiving portion, and the surface on the other end side of the annular member is provided on the other abutting surface on the body portion. The pressure detecting device according to claim 1, wherein the pressure detecting device is arranged so as to face the pressure detecting device. 先端部側となる燃焼室内と後端部側となる外部とを連通する連通孔が形成されたシリンダヘッドと、
前記連通孔に挿入されることで前記シリンダヘッドに取り付けられるとともに、前記燃焼室内の圧力を検出する圧力検出装置と
を備え、
前記圧力検出装置は、
前記連通孔内に配置される筒状の胴体部と、
筒状の筒状部と当該筒状部の一端部側で当該筒状部を塞ぐ閉塞部とを有し、当該筒状部の他端部側が前記胴体部の一端部側に設けられるとともに当該閉塞部が前記燃焼室から圧力を受ける受圧部と、
前記胴体部の内側に設けられ、前記受圧部が受けた圧力に応じた信号を発生する信号発生部と、
前記受圧部よりも熱伝導率が低い無機材料で構成され、前記筒状部の外側に取り付けられるとともに、前記連通孔の内周面と非接触に配置される環状の環状部材と
を含む圧力検出装置付き内燃機関。 A cylinder head with a communication hole that communicates between the combustion chamber on the front end side and the outside on the rear end side.
It is attached to the cylinder head by being inserted into the communication hole, and is provided with a pressure detecting device for detecting the pressure in the combustion chamber.
The pressure detector is
A tubular body portion arranged in the communication hole and
It has a tubular tubular portion and a closing portion that closes the tubular portion on one end side of the tubular portion, and the other end side of the tubular portion is provided on one end side of the body portion and the said A pressure receiving part where the closed part receives pressure from the combustion chamber,
A signal generating unit provided inside the body portion and generating a signal according to the pressure received by the pressure receiving unit, and a signal generating unit.
Pressure detection composed of an inorganic material having a thermal conductivity lower than that of the pressure receiving portion, attached to the outside of the tubular portion, and including an annular member arranged in a non-contact manner with the inner peripheral surface of the communication hole. Internal combustion engine with equipment.
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