JP2007017452A

JP2007017452A - Gas sensor

Info

Publication number: JP2007017452A
Application number: JP2006255856A
Authority: JP
Inventors: Kazuya Nakagawa; 和也中川; Kazuhiro Okazaki; 和弘岡崎
Original assignee: Denso Corp
Current assignee: Denso Corp
Priority date: 2001-02-28
Filing date: 2006-09-21
Publication date: 2007-01-25

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gas sensor capable of being utilized in the detection of the concentration of NOx or the like and excellent in responsiveness. <P>SOLUTION: An inside cover 22 and an outside cover 21 respectively have an introducing holes 210 and 220 for introducing a gas to be measured and the introducing hole 220 provided on the inside cover 22 is provided on a base end side from the introducing holes 210 provided on the outside cover 21. A cover 2 on the side of a gas to be measured is constituted so that the gas to be measured is introduced into the chamber 200 of the gas to be measured from the introducing hole 220 provided on the inside cover 22 while being introduced from the introducing holes 210 provided on the outside cover 21 and forming the gas flow going toward the base end side of the clearance between the outside and inside covers 21 and 22 from the leading end thereof and a step part 211 changed over in the side of a diameter is provided on the outside cover 21. A taper part 222 constituted so as to be reduced in diameter toward the leading end part from the base end part is provided on a part of at least the side surface of the inside cover 22 and the introducing hole 220 is provided on the part provided with the taper part 222 of the inside cover 22. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

本発明は、内燃機関の排気系等に設置して、酸素濃度、空燃比、ＮＯｘ濃度等の検出に利用可能なガスセンサに関する。 The present invention relates to a gas sensor that is installed in an exhaust system or the like of an internal combustion engine and can be used for detecting oxygen concentration, air-fuel ratio, NOx concentration, and the like.

自動車エンジンの排気系にはエンジンの燃焼制御のためにガスセンサが設けてある。
このガスセンサは、筒状のハウジングに被測定ガス中の特定ガス濃度検出用のガスセンサ素子を配置し、該ハウジングの基端側に大気側カバーが、先端側に内側カバーと外側カバーとよりなる被測定ガス側カバーが設けてある。 An exhaust system of an automobile engine is provided with a gas sensor for engine combustion control.
In this gas sensor, a gas sensor element for detecting a specific gas concentration in a gas to be measured is arranged in a cylindrical housing, and an air cover is provided on the base end side of the housing, and an inner cover and an outer cover are provided on the distal end side. A measuring gas side cover is provided.

図１６及び図１７に示すごとく、上記内側カバー９２の内部は被測定ガス室９００で、上記内側カバー９２及び上記外側カバー９１は、上記被測定ガス室９００に対し被測定ガスを導入する導入穴２１０、２２０をそれぞれ有する。また、上記外側カバー９１に設けた導入穴２１０よりも上記内側カバー９２に設けた導入穴２２０のほうが、よりガスセンサの基端側（後述する図１参照、また図１６及び図１７においては図面上方が基端側である。）に位置する。 As shown in FIGS. 16 and 17, the inside of the inner cover 92 is a measured gas chamber 900, and the inner cover 92 and the outer cover 91 are introduction holes for introducing the measured gas into the measured gas chamber 900. 210 and 220 respectively. Further, the introduction hole 220 provided in the inner cover 92 is more proximal than the introduction hole 210 provided in the outer cover 91 (see FIG. 1 described later, and in FIG. 16 and FIG. Is the proximal side.

図１６、図１７に示すごとく、被測定ガスは外側カバー９１に設けた導入穴２１０より進入し、両カバー９１、９２間のクリアランス２５を先端側から基端側に向かって移動するガス流れ８１を形成しつつ、内側カバー９２に設けた導入穴２２０より内側カバー９２内に形成された被測定ガス室９００に入る。 As shown in FIGS. 16 and 17, the gas to be measured enters from the introduction hole 210 provided in the outer cover 91, and the gas flow 81 moves through the clearance 25 between the covers 91 and 92 from the distal end side toward the proximal end side. The gas chamber 900 to be measured is formed in the inner cover 92 through the introduction hole 220 provided in the inner cover 92.

しかしながら、上記従来構造の被測定ガス側カバー９を備えたガスセンサには以下に示すような問題がある。
図１６、図１７に示すごとく、クリアランス２５の基端側（図面上方）において、導入穴２２０に入れなかったガス流れの一部がそのまま基端側に向かい、基端側の端部で跳ね返って先端側へと向かう戻り流れ８２が生じることがある。
この戻り流れ８２が原因となって、クリアランス２５の基端側でガス流れ８１が妨害され、導入穴２２０から被測定ガス室９００へ被測定ガスの導入効率が低下する。
したがって、濃度や状態が変動する被測定ガスをタイムラグなしに被測定ガス室９００に導入することが困難となり、ガスセンサの応答性遅れの原因となる。 However, the gas sensor provided with the measured gas side cover 9 having the conventional structure has the following problems.
As shown in FIGS. 16 and 17, on the proximal end side (upper side of the drawing) of the clearance 25, a part of the gas flow that has not been put into the introduction hole 220 is directed toward the proximal end and rebounds at the proximal end portion. A return flow 82 toward the distal end may occur.
Due to the return flow 82, the gas flow 81 is obstructed on the proximal end side of the clearance 25, and the introduction efficiency of the measurement gas from the introduction hole 220 to the measurement gas chamber 900 is reduced.
Therefore, it becomes difficult to introduce the gas to be measured whose concentration and state fluctuate into the gas chamber 900 to be measured without a time lag, which causes a delay in response of the gas sensor.

本発明は、かかる従来の問題点に鑑みてなされたもので、応答性に優れるガスセンサを提供しようとするものである。 The present invention has been made in view of such conventional problems, and an object of the present invention is to provide a gas sensor having excellent responsiveness.

請求項１記載の発明は、筒状のハウジングに被測定ガス中の特定ガス濃度検出用のガスセンサ素子が挿通され、該ハウジングの基端側に大気側カバーが、先端側に内側カバーと外側カバーとよりなる被測定ガス側カバーが設けてあるガスセンサにおいて、
上記内側カバーの内部に被測定ガス室が形成され、
上記内側カバーおよび上記外側カバーは、上記被測定ガス室に対し被測定ガスを導入するための導入穴をそれぞれの側面に有し、上記外側カバーに設けた導入穴よりも上記内側カバーに設けた導入穴はより基端側に存在すると共に、
上記外側カバーに設けた導入穴より導入され、上記外側カバーと上記内側カバーとの間のクリアランスを先端側から基端側に向かうガス流れを形成しつつ、上記内側カバーに設けた導入穴より、被測定ガスが被測定ガス室に導入されるように上記被測定ガス側カバーは構成され、
上記外側カバー及び／または上記内側カバーに径の大きさが切り替わる段部を設け、
上記外側カバー及び／または上記内側カバーの少なくとも側面の一部分に、基端側から先端側に向かって径細となるように、または先端側から基端側に向けて径細となるように構成されたテーパー部を設け、
上記内側カバーのテーパー部を設けた部分に上記導入穴が設けてあることを特徴とするガスセンサにある（図２参照）。 According to the first aspect of the present invention, a gas sensor element for detecting a specific gas concentration in a gas to be measured is inserted into a cylindrical housing, an atmosphere side cover is provided at the proximal end side of the housing, and an inner cover and an outer cover are provided at the distal end side. In the gas sensor provided with the measured gas side cover consisting of
A gas chamber to be measured is formed inside the inner cover,
The inner cover and the outer cover each have an introduction hole for introducing a gas to be measured into the gas chamber to be measured, and are provided in the inner cover rather than the introduction hole provided in the outer cover. The introduction hole exists on the more proximal side,
From the introduction hole provided in the inner cover while forming a gas flow that is introduced from the introduction hole provided in the outer cover and the clearance between the outer cover and the inner cover is directed from the distal end side to the proximal end side, The measured gas side cover is configured so that the measured gas is introduced into the measured gas chamber,
Provide a step portion whose diameter is switched on the outer cover and / or the inner cover,
The outer cover and / or at least part of the side surface of the inner cover is configured so that the diameter decreases from the proximal end side toward the distal end side, or the diameter decreases from the distal end side toward the proximal end side. Taper part
The gas sensor is characterized in that the introduction hole is provided in a portion where the tapered portion of the inner cover is provided (see FIG. 2).

上記外側カバーの導入穴から入った被測定ガスは、上記内側カバーとのクリアランスを通り、上記内側カバーの導入穴に入るというガス流れを形成するが、段部によってクリアランスを大きくすることができるため、ガス流れと戻り流れとの間隔を遠ざけて、戻り流れからの影響を受け難くすることができる。
また、テーパー部によって、ガス流れがテーパー部に沿って流れるため、戻り流れの影響を受け難くすることができる。 The gas to be measured that has entered from the introduction hole of the outer cover passes through the clearance with the inner cover and forms a gas flow that enters the introduction hole of the inner cover. However, the clearance can be increased by the stepped portion. The distance between the gas flow and the return flow can be increased to make it less susceptible to the influence of the return flow.
Further, since the gas flow flows along the tapered portion by the tapered portion, it is possible to make it less susceptible to the influence of the return flow.

よって、テーパー部に設けた内側カバーの導入穴へ戻り流れの影響を受け難いまま、被測定ガスを導入することができ、内側カバーの導入穴への被測定ガス導入を速やかに行うことができる。そのため、濃度や変動する被測定ガスを状態を被測定ガス室に対し速やかに反映させることができる。 Therefore, the gas to be measured can be introduced into the introduction hole of the inner cover provided in the tapered portion without being affected by the flow, and the gas to be measured can be quickly introduced into the introduction hole of the inner cover. . Therefore, it is possible to quickly reflect the state of the gas to be measured and the concentration and the gas to be measured to the gas chamber to be measured.

以上、本発明によれば、応答性に優れるガスセンサを提供することができる。 As mentioned above, according to this invention, the gas sensor excellent in responsiveness can be provided.

請求項２記載の発明のように、上記外側カバーは径の大きさが切り替わる段部が設けてあり、上記内側カバーは、上記外側カバーに設けた段部よりも基端側において、基端側から先端側に向けて径細となるテーパー部が設けてあり、かつ該テーパー部よりも先端側は径が一定となるストレート部であると共に、上記内側カバーは、上記テーパー部を設けた部分に対し上記導入穴を設け、
上記外側カバーの段部を設けた部分における上記外側カバーと上記内側カバーとの間のクリアランスＣ１と、
上記内側カバーのストレート部と該ストレート部と対面する上記外側カバーとの間のクリアランスＸとの間には、Ｃ１＞Ｘという関係が成立することが好ましい（実施形態例１参照）。 According to a second aspect of the present invention, the outer cover is provided with a step portion whose diameter is switched, and the inner cover is on the base end side of the step portion provided on the outer cover. A taper portion having a diameter that is narrower toward the tip end side, and a straight portion having a constant diameter on the tip end side than the taper portion, and the inner cover is formed on a portion provided with the taper portion. For the above introduction hole,
A clearance C1 between the outer cover and the inner cover in a portion where the step portion of the outer cover is provided;
A relationship of C1> X is preferably established between the straight portion of the inner cover and the clearance X between the outer cover facing the straight portion (see Embodiment 1).

上記外側カバーの導入穴から入った被測定ガスは、上記内側カバーとのクリアランスを通り、上記内側カバーの導入穴に入るというガス流れを形成するが、段部はテーパー部よりも先端側、つまりガス流れの上流側にある。
また、段部でのクリアランスＣ１は、該段部よりもガス流れの上流側にあるストレート部でのクリアランスＸよりも広い。
従って、外側カバーの導入穴より導入された被測定ガスは、外側カバーと内側カバーとの間をガス流れを形成し、段部と対面する個所を通過する（ここがクリアランスＣ１の位置である）。 The gas to be measured that has entered from the introduction hole of the outer cover passes through the clearance with the inner cover and forms a gas flow that enters the introduction hole of the inner cover. Located upstream of the gas flow.
The clearance C1 at the step portion is wider than the clearance X at the straight portion on the upstream side of the gas flow from the step portion.
Therefore, the gas to be measured introduced from the introduction hole of the outer cover forms a gas flow between the outer cover and the inner cover, and passes through the portion facing the step portion (this is the position of the clearance C1). .

そして、段部以降は、被測定ガスは内側カバーのテーパー部に沿って流れるため、戻り流れの影響を受け難い。さらに、内側カバーのテーパー部に導入穴が設けてあるため、戻り流れの影響を受け難い状態のままで被測定ガス室に被測定ガスは導入される。さらに、段部でのクリアランスＣ１はストレート部のクリアランスＸよりも広いため、さらに戻り流れの影響を受け難い。
よって、テーパー部に設けた内側カバーの導入穴へ、速やかに被測定ガスを導入することができる。 After the step portion, the gas to be measured flows along the tapered portion of the inner cover, and thus is not easily affected by the return flow. Furthermore, since the introduction hole is provided in the tapered portion of the inner cover, the gas to be measured is introduced into the gas chamber to be measured while being hardly affected by the return flow. Further, since the clearance C1 at the stepped portion is wider than the clearance X at the straight portion, it is less susceptible to the influence of the return flow.
Therefore, the gas to be measured can be quickly introduced into the introduction hole of the inner cover provided in the tapered portion.

なお、クリアランスＣ１は段部の中央で、ガスセンサ軸方向に対して直交する方向に測定した距離であり、クリアランスＸはストレート部で、同じく軸方向に直交する方向に測定した距離である。詳細は後述する図３に記載した。 The clearance C1 is the distance measured in the direction perpendicular to the gas sensor axial direction at the center of the stepped portion, and the clearance X is the distance measured in the straight portion and also in the direction perpendicular to the axial direction. Details are shown in FIG.

仮に、Ｃ１がＸと同じかＸより小さい場合は、Ｃ１の位置でガス流れが乱れて、戻り流れが生じたり、乱流が生じるなどして、内側カバーの導入穴への被測定ガスの到達が遅れるおそれがある。 If C1 is the same as X or smaller than X, the gas flow is disturbed at the position of C1, and a return flow or a turbulent flow occurs, so that the gas to be measured reaches the introduction hole of the inner cover. May be delayed.

次に、請求項３記載の発明のように、上記外側カバーは径方向内側に凹んだ溝部を有することが好ましい（図１４参照）。
上記溝部によって、外側カバーの導入穴から入った被測定ガスがすべて内側カバーの導入穴に確実に向かうように、ガス流れを整流することができる。よって、より高い応答性を持ったガスセンサを得ることができる。
具体的な溝部の構成としては、外側カバーの周方向に等間隔で複数個の導入穴を設けたケースでは、この外側カバーにおける導入穴の間に対しガスセンサ軸方向が長軸となるような形状の溝部を設けることができる。 Next, as in a third aspect of the invention, the outer cover preferably has a groove that is recessed radially inward (see FIG. 14).
The groove portion makes it possible to rectify the gas flow so that all the gas to be measured entering from the introduction hole of the outer cover is surely directed to the introduction hole of the inner cover. Therefore, a gas sensor with higher responsiveness can be obtained.
As a specific configuration of the groove, in a case where a plurality of introduction holes are provided at equal intervals in the circumferential direction of the outer cover, the gas sensor axial direction is a long axis between the introduction holes in the outer cover. Can be provided.

実施形態例１
本発明の実施形態例にかかるガスセンサにつき、図１〜図５を用いて説明する。
図１〜図３に示すごとく、本例のガスセンサ１は、筒状のハウジング１０に被測定ガス中の特定ガス濃度検出用のガスセンサ素子１５が挿通され、該ハウジング１０の基端側に大気側カバー１１が、先端側に内側カバー２２と外側カバー２１とよりなる被測定ガス側カバー２が設けてある。 Embodiment 1
A gas sensor according to an embodiment of the present invention will be described with reference to FIGS.
As shown in FIGS. 1 to 3, in the gas sensor 1 of this example, a gas sensor element 15 for detecting a specific gas concentration in a gas to be measured is inserted into a cylindrical housing 10, and the atmosphere side is located on the base end side of the housing 10. The measured gas side cover 2 including the inner cover 22 and the outer cover 21 is provided on the front end side of the cover 11.

上記内側カバー２２の内部は被測定ガス室２００が形成され、上記内側カバー２２および上記外側カバー２１は、上記被測定ガス室２００に対し被測定ガスを導入するための導入穴２１０、２２０をそれぞれ側面に有し、上記外側カバー２１に設けた導入穴２１０よりも上記内側カバー２２に設けた導入穴２２０のほうが、より基端側に設けてある。 A gas chamber 200 to be measured is formed inside the inner cover 22, and the inner cover 22 and the outer cover 21 have introduction holes 210 and 220 for introducing the gas to be measured into the gas chamber 200 to be measured, respectively. The introduction hole 220 provided in the inner cover 22 is provided on the base end side rather than the introduction hole 210 provided on the side surface and provided in the outer cover 21.

上記被測定ガス側カバー２は、上記外側カバー２１に設けた導入穴２１０より導入され、上記外側カバー２１と上記内側カバー２２との間のクリアランス２５を先端側から基端側に向かうガス流れ８１を形成しつつ、上記内側カバー２２に設けた導入穴２２０より被測定ガス室２００に被測定ガスが導入されるよう構成されている。
そして、上記被測定ガス側カバー２は、上記ガス流れ８１から分岐した基端側から先端側に向かう戻り流れ８２の影響を受け難くなるように構成されている。 The measured gas side cover 2 is introduced from an introduction hole 210 provided in the outer cover 21, and a gas flow 81 from the distal end side toward the proximal end side through the clearance 25 between the outer cover 21 and the inner cover 22. The measurement gas is introduced into the measurement gas chamber 200 through the introduction hole 220 provided in the inner cover 22.
The measured gas side cover 2 is configured to be hardly affected by the return flow 82 from the proximal end side branched from the gas flow 81 toward the distal end side.

戻り流れ８２の影響を受け難くなる構成について具体的に記載する。
上記被測定ガス側カバー２において、上記外側カバー２１は径の大きさが切り替わる段部２１１が設けてある。この段部２１１より先端側は径細、基端側が径太に構成する。上記内側カバー２２は、上記段部２１１よりも基端側において、基端側から先端側に向けて径細となるテーパー部２２２が設けてある。
また、上記内側カバー２２においては、上記テーパー部２２２を設けた部分に対し、上記導入穴２２０が設けてある。 The configuration that is less susceptible to the influence of the return flow 82 will be specifically described.
In the measured gas side cover 2, the outer cover 21 is provided with a step portion 211 whose diameter is switched. The tip end side of the stepped portion 211 is formed with a small diameter, and the base end side is formed with a large diameter. The inner cover 22 is provided with a tapered portion 222 having a diameter decreasing from the proximal end side toward the distal end side on the proximal end side with respect to the stepped portion 211.
In the inner cover 22, the introduction hole 220 is provided in a portion where the tapered portion 222 is provided.

なお、本実施形態例、及び他の実施形態例にて用いた各図面では、図面上方が基端側、図面下方が先端側である。外側カバーや内側カバーのフランジ部のある個所が基端側、底部のある個所が先端側となるが、各説明において記載は省略する。 In the drawings used in this embodiment and other embodiments, the upper side of the drawing is the base end side, and the lower side of the drawing is the tip side. The location of the outer cover and the flange portion of the inner cover is the proximal end side, and the location of the bottom portion is the distal end side, but the description is omitted in each description.

以下、詳細に説明する。
本例にかかるガスセンサは、自動車エンジンの排気系に取りつけて、エンジンの燃焼制御に利用する。
図１に示すごとく、金属製の筒状のハウジング１０に対し、先端側絶縁碍子１２が配置され、該先端側絶縁碍子１２に対し、ガスセンサ素子１５が封止材１２１によって気密的に挿通されている。 Details will be described below.
The gas sensor according to this example is attached to an exhaust system of an automobile engine and is used for engine combustion control.
As shown in FIG. 1, a tip side insulator 12 is arranged with respect to a metal cylindrical housing 10, and a gas sensor element 15 is hermetically inserted into the tip side insulator 12 by a sealing material 121. Yes.

上記ガスセンサ素子１５の基端側を覆うように基端側絶縁碍子１３が大気側カバー１１内に配置され、該基端側絶縁碍子１３内部において、ガスセンサ素子１５はリード部１３１に対し電気的に接続される。
上記リード部１３１はコネクタ部１４１を介してガスセンサ１外に延設されるリード線１４２に接続される。
また、大気側カバー１１の基端側は弾性絶縁部材１６が配置されている。 A base end side insulator 13 is disposed in the atmosphere side cover 11 so as to cover the base end side of the gas sensor element 15, and the gas sensor element 15 is electrically connected to the lead portion 131 inside the base end side insulator 13. Connected.
The lead portion 131 is connected to a lead wire 142 extending outside the gas sensor 1 through a connector portion 141.
An elastic insulating member 16 is disposed on the base end side of the atmosphere-side cover 11.

上記ハウジング１０の先端側には内側カバー２２と外側カバー２１とよりなる被測定ガス側カバー２が設けてある。
基端側は大気側カバー１１が設けてあり、該大気側カバー１１の基端側には撥水フィルタ１１２を介して外部カバー１１３が設けてある。外側カバー１１３と大気側カバー１１には、大気導入穴１１５が設けてあり、大気側カバー１１の内部の大気側雰囲気１１０に対し大気導入を行うよう構成されている。 A measured gas side cover 2 including an inner cover 22 and an outer cover 21 is provided on the front end side of the housing 10.
An atmosphere side cover 11 is provided on the base end side, and an external cover 113 is provided on the base end side of the atmosphere side cover 11 via a water repellent filter 112. The outer cover 113 and the atmosphere-side cover 11 are provided with an atmosphere introduction hole 115 so that the atmosphere is introduced into the atmosphere-side atmosphere 110 inside the atmosphere-side cover 11.

図２、図３に示すごとく、外側カバー２１及び内側カバー２２は有底円筒状で、底部２１８、２２８にガス流通穴２１９、２２９が設けられ、側面に複数個の導入穴２１０、２２０が設けてある。導入穴２１０、２２０は底部から同一の高さで周方向には等間隔で配置される。また、その穴径も略同一で、形状は円形である。外側カバー２１の導入穴２１０は先端側に、内側カバー２２の導入穴２２０は基端側に設けてある。 As shown in FIGS. 2 and 3, the outer cover 21 and the inner cover 22 have a bottomed cylindrical shape, gas flow holes 219 and 229 are provided in the bottom portions 218 and 228, and a plurality of introduction holes 210 and 220 are provided on the side surfaces. It is. The introduction holes 210 and 220 are arranged at equal intervals in the circumferential direction at the same height from the bottom. Moreover, the hole diameter is substantially the same, and the shape is circular. The introduction hole 210 of the outer cover 21 is provided on the distal end side, and the introduction hole 220 of the inner cover 22 is provided on the proximal end side.

また、外側カバー２１及び内側カバー２２の基端側は上記ハウジング１０の基端側の端面１０１に設けた凹所１０２に対する嵌合用のフランジ２９がそれぞれ設けてある。
外側カバー２１は径方向内側に向かう段部２１１が導入穴２１０よりも基端側で、該外側カバー２１の中ほどに設けてある。 Further, the base end sides of the outer cover 21 and the inner cover 22 are respectively provided with flanges 29 for fitting into the recesses 102 provided on the end face 101 on the base end side of the housing 10.
The outer cover 21 is provided with a step portion 211 directed radially inward in the middle of the outer cover 21 on the base end side with respect to the introduction hole 210.

図３に示すごとく、内側カバー２２は嵌合用のフランジ２９を設けた箇所の下方から先端側に向って、より径細になるように構成されたテーパー部２２２を有し、外側カバー２１に設けた段部２１１より基端側でテーパー部２２２は終了し、あとは底部２２８まで径が一定のストレート部２２３が設けてある。また、上記内側カバー２２においては、導入穴２２０はテーパー部２２２の箇所に対し設けてある。
上記ストレート部２２３と対面する位置の外側カバー２１との間のクリアランスＸは０．９ミリ、テーパー部２２２を設けた部分の角度θは３０°である。 As shown in FIG. 3, the inner cover 22 has a tapered portion 222 configured to become thinner from the lower side to the tip side where the fitting flange 29 is provided, and is provided on the outer cover 21. The tapered portion 222 ends on the proximal end side from the stepped portion 211, and a straight portion 223 having a constant diameter is provided up to the bottom portion 228. In the inner cover 22, the introduction hole 220 is provided at the tapered portion 222.
The clearance X between the straight portion 223 and the outer cover 21 at the position facing the straight portion 223 is 0.9 mm, and the angle θ of the portion provided with the tapered portion 222 is 30 °.

また、図３に示すごとく、外側カバー２１の段部２１１を設けた部分における外側カバー２１と内側カバー２２との間のクリアランスＣ１とクリアランスＸとの間には、Ｃ１＞Ｘという関係が成立し、Ｃ１＝１．５ミリ、Ｘ＝０．９ミリである。 Further, as shown in FIG. 3, a relationship of C1> X is established between the clearance C1 and the clearance X between the outer cover 21 and the inner cover 22 in the portion where the step portion 211 of the outer cover 21 is provided. C1 = 1.5 mm and X = 0.9 mm.

次に、本例にかかる形状の被測定ガス側カバー２の性能について以下に示す試験を行った。
図１〜図３にかかるガスセンサ及び被測定ガス側カバーを用いて、ガスセンサの応答性を測定した。
４気筒エンジンの３気筒の空燃比を１４．５に合わせ、１気筒を他の３気筒より１０％空燃比が濃い側にセットする。これにより４気筒エンジンから排出される排ガスの酸素濃度が周期的に変化する。 Next, the following test was performed on the performance of the measured gas side cover 2 having the shape according to this example.
The responsiveness of the gas sensor was measured using the gas sensor and the measured gas side cover according to FIGS.
The air-fuel ratio of the three cylinders of the four-cylinder engine is set to 14.5, and one cylinder is set on the side where the air-fuel ratio is 10% higher than that of the other three cylinders. Thereby, the oxygen concentration of the exhaust gas discharged from the 4-cylinder engine changes periodically.

このような排ガスに空燃比センサを曝して、エンジンの空燃比を測定すると、排ガスの周期的な酸素濃度変化に応じてセンサ出力が周期的に変化する。センサの応答性は周期的変化の振幅に関係する。
応答性が速いと振幅が大きくなり、遅いと小さくなる。これを利用して本例にかかるガスセンサを上述の４気筒エンジンからの排ガスに曝して振幅の大小を評価し、応答性を測定した。 When the air-fuel ratio sensor is exposed to such exhaust gas and the air-fuel ratio of the engine is measured, the sensor output periodically changes according to the periodic oxygen concentration change of the exhaust gas. The responsiveness of the sensor is related to the amplitude of the periodic change.
Amplitude increases when response is fast, and decreases when response is slow. Using this, the gas sensor according to this example was exposed to the exhaust gas from the above-described four-cylinder engine, the magnitude of the amplitude was evaluated, and the response was measured.

また、上記と同様の方法で、後述する図１６、図１７に示すごとき従来の被測定ガス側カバー９をもったガスセンサについても応答性を測定した。
この従来の被測定ガス側カバー９は外側、内側カバー９１、９２共にストレート状態であり、クリアランスＷは１．０ミリである。 In addition, the responsiveness of the conventional gas sensor having the measured gas side cover 9 as shown in FIG. 16 and FIG.
In this conventional gas-side cover 9 to be measured, both the outer and inner covers 91 and 92 are in a straight state, and the clearance W is 1.0 mm.

従来の被測定ガス側カバーを備えたガスセンサの出力の振幅を１５本について測定したところ、図４に示すごとく、平均が０．１Ａ／Ｆ付近であった。本例の被測定ガス側カバーを備えたガスセンサの出力の平均の振幅は０．１７Ａ／Ｆ付近で、従来のガスセンサよりも１．７倍ほど振幅が大きく、それだけ本例にかかるガスセンサが応答性に優れていることがわかった。 When the amplitude of the output of the conventional gas sensor provided with the gas side cover to be measured was measured for 15 lines, the average was around 0.1 A / F as shown in FIG. The average amplitude of the output of the gas sensor provided with the gas side cover to be measured in this example is about 0.17 A / F, which is 1.7 times larger than that of the conventional gas sensor, and the gas sensor according to this example is responsive. It was found to be excellent.

本例の作用効果について説明する。
本例のガスセンサ１は、被測定ガス側カバー２における内側カバー２２と外側カバー２１との間のクリアランス２５内において、ガス流れ８１が戻り流れ８２の影響を受け難く構成されている。 The effect of this example will be described.
The gas sensor 1 of this example is configured such that the gas flow 81 is hardly affected by the return flow 82 in the clearance 25 between the inner cover 22 and the outer cover 21 in the measured gas side cover 2.

つまり、上記外側カバー２１の導入穴２１０から入った被測定ガスは、上記内側カバー２２とのクリアランスを通り、上記内側カバー２２の導入穴２２０に入るというガス流れ８１を形成するが、段部２１１はテーパー部２２２よりも先端側、つまりガス流れ８１の上流側にある。
また、図３に示すごとく、段部２１１でのクリアランスＣ１は、該段部２１１よりもガス流れの上流側にあるストレート部でのクリアランスＸよりも広い。
従って、外側カバー２１の導入穴２１０より導入された被測定ガスは、外側カバー２１と内側カバー２２との間をガス流れ８１を形成し、段部２１１と対面する個所を通過する（ここがクリアランスＣ１の位置である）。 That is, the gas to be measured that has entered from the introduction hole 210 of the outer cover 21 passes through the clearance with the inner cover 22 and forms a gas flow 81 that enters the introduction hole 220 of the inner cover 22. Is on the tip side of the tapered portion 222, that is, on the upstream side of the gas flow 81.
Further, as shown in FIG. 3, the clearance C1 at the step portion 211 is wider than the clearance X at the straight portion on the upstream side of the gas flow from the step portion 211.
Accordingly, the gas to be measured introduced from the introduction hole 210 of the outer cover 21 forms a gas flow 81 between the outer cover 21 and the inner cover 22 and passes through the portion facing the step portion 211 (this is the clearance). C1 position).

そして、段部２１１以降は、被測定ガスは内側カバー２２のテーパー部２２２に沿って流れるため、戻り流れ８２の影響を受け難い。さらに、内側カバー２２のテーパー部２２２に導入穴２２０が設けてあるため、戻り流れ８２の影響を受け難い状態のままで被測定ガス室２０に被測定ガスは導入される。 After the step portion 211, the gas to be measured flows along the tapered portion 222 of the inner cover 22, so that it is difficult to be affected by the return flow 82. Further, since the introduction hole 220 is provided in the tapered portion 222 of the inner cover 22, the measurement gas is introduced into the measurement gas chamber 20 while being hardly affected by the return flow 82.

さらに、段部２１１でのクリアランスＣ１はストレート部のクリアランスＸよりも広いため、さらに戻り流れ８２の影響を受け難い。
そのため、テーパー部２２２に設けた内側カバー２２の導入穴２２０へ戻り流れ８２の影響を受け難いまま、素早く被測定ガスを導入することができる。
よって、本例のガスセンサ１では、内側カバー２２の導入穴２２０への被測定ガス導入が妨げられ難く、被測定ガスを被測定ガス室２００に速やかに導入することができる。
以上、本例によれば、応答性に優れるガスセンサを提供することができる。 Furthermore, since the clearance C1 at the step portion 211 is wider than the clearance X at the straight portion, the clearance is less susceptible to the return flow 82.
Therefore, it is possible to quickly introduce the gas to be measured without being influenced by the flow 82 returning to the introduction hole 220 of the inner cover 22 provided in the tapered portion 222.
Therefore, in the gas sensor 1 of this example, it is difficult to prevent the measurement gas from being introduced into the introduction hole 220 of the inner cover 22, and the measurement gas can be quickly introduced into the measurement gas chamber 200.
As described above, according to this example, it is possible to provide a gas sensor with excellent responsiveness.

また、本例のガスセンサ１には積層型の板状のガスセンサ素子が搭載されたが、図５に示すごとく、コップ型のガスセンサ素子３６を搭載することもできる。
このガスセンサ３は、ハウジング１０に対し、コップ型のガスセンサ素子３６が、粉末シール材３１１、絶縁碍子３１２を介して、金属リング３１３を挟んだハウジング１０基端側のかしめ固定により、気密的に挿通されている。
ガスセンサ素子３６は、コップ型の固体電解質体３６１と該固体電解質体３６１内部に配置された棒状ヒータ３６２とよりなる。 Further, although the laminated plate-shaped gas sensor element is mounted on the gas sensor 1 of the present example, as shown in FIG. 5, a cup-type gas sensor element 36 can also be mounted.
In this gas sensor 3, a cup-type gas sensor element 36 is hermetically inserted into the housing 10 by caulking and fixing on the base end side of the housing 10 with the metal ring 313 sandwiched between the powder sealing material 311 and the insulator 312. Has been.
The gas sensor element 36 includes a cup-shaped solid electrolyte body 361 and a rod-like heater 362 disposed inside the solid electrolyte body 361.

このガスセンサ素子３６に対し出力取り出し用端子を持ったリード部３４１が電気的に接続され、大気側カバー１１内の絶縁碍子３３内でコネクタ部３４２を介してリード線３４３に接続される。
上記ガスセンサ３に対し、本例にかかる被測定ガス側カバー２を設けた場合も、上述と同様の作用効果を得ることができる。 A lead portion 341 having an output extraction terminal is electrically connected to the gas sensor element 36, and is connected to the lead wire 343 through the connector portion 342 in the insulator 33 in the atmosphere-side cover 11.
Even when the measured gas side cover 2 according to this example is provided for the gas sensor 3, the same effects as described above can be obtained.

参考例１
本例は、図６に示すごとく、外側カバー２１と内側カバー２２との間は大クリアランス部分２５１とこれよりも狭い小クリアランス部分２５２とが形成されている被測定ガス側カバー２について説明する。
図６に示すごとく、大クリアランス部分２５１の幅Ｗ１は１．５ミリである。小クリアランス部分２５２の幅Ｗ２は０．９ミリである。つまり、Ｗ１はＷ２の１．１倍以上である。
また、本例の外側カバー２１に段部２１１が設けてあり、内側カバー２２はフランジ２９の下方に段部２２１が設けてあり、該段部２２１のすぐ下に導入穴２２０が配置されている。
その他詳細な構成は実施形態例１と同様である。 Reference example 1
In this example, as shown in FIG. 6, the measured gas side cover 2 in which a large clearance portion 251 and a smaller clearance portion 252 narrower than this are formed between the outer cover 21 and the inner cover 22 will be described.
As shown in FIG. 6, the width W1 of the large clearance portion 251 is 1.5 mm. The width W2 of the small clearance portion 252 is 0.9 mm. That is, W1 is 1.1 times or more W2.
Further, the outer cover 21 of this example is provided with a stepped portion 211, the inner cover 22 is provided with a stepped portion 221 below the flange 29, and an introduction hole 220 is disposed immediately below the stepped portion 221. .
Other detailed configurations are the same as those of the first embodiment.

また、本例では、大クリアランス部分２５１の幅Ｗ１が小クリアランス部分の幅Ｗ２の１．１倍以上であるため、大クリアランス部分２５１において、ガス流れ８１と戻り流れ８２との間隔を遠ざけて、戻り流れ８２からの影響を受け難くすることができ、被測定ガスを速やかに被測定ガス室２００に導入することができる。
その他は、実施形態例１と同様の作用効果を有する。 In this example, since the width W1 of the large clearance portion 251 is 1.1 times or more the width W2 of the small clearance portion, the gap between the gas flow 81 and the return flow 82 is increased in the large clearance portion 251. The influence of the return flow 82 can be reduced, and the gas to be measured can be quickly introduced into the gas chamber 200 to be measured.
The other effects are the same as those of the first embodiment.

参考例２
本例は、図７に示すごとく、外側カバー２１に段部２１１が設けてある被測定ガス側カバー２について説明する。
図７に示すごとく、外側カバー２１には段部２１１が設けてあり、内側カバー２２はフランジ２９よりすぐ下から底部まで、径が一定のストレート部２２３を有する。
その他詳細な構成は実施形態例１と同様であり、同様の作用効果を有する。 Reference example 2
In this example, as shown in FIG. 7, the measured gas side cover 2 in which the outer cover 21 is provided with a step portion 211 will be described.
As shown in FIG. 7, the outer cover 21 is provided with a stepped portion 211, and the inner cover 22 has a straight portion 223 having a constant diameter from just below the flange 29 to the bottom.
The other detailed configuration is the same as that of the first embodiment and has the same effects.

参考例３
本例は、図８に示すごとく、内側カバー２２にテーパー部２２２が設けてある被測定ガス側カバー２について説明する。
図８に示すごとく、外側カバー２１はフランジより下方から底部２１８まで径が一定のストレート部２１３を有する。内側カバー２２はフランジ部２９よりすぐ下にテーパー部２２２を有する。そして、内側カバー２２は中央付近の切替部２２６においてテーパー部２２２が終了し、切替部２２６より先端側は径が一定のストレート部２２３である。
その他詳細な構成は実施形態例１と同様である。 Reference example 3
In this example, as shown in FIG. 8, the measured gas side cover 2 in which the inner cover 22 is provided with a tapered portion 222 will be described.
As shown in FIG. 8, the outer cover 21 has a straight portion 213 having a constant diameter from below the flange to the bottom portion 218. The inner cover 22 has a tapered portion 222 immediately below the flange portion 29. The inner cover 22 has a tapered portion 222 at the switching portion 226 near the center, and a straight portion 223 having a constant diameter on the tip side of the switching portion 226.
Other detailed configurations are the same as those of the first embodiment.

本例では、テーパー部２２２を設けたので、内側カバー２２の傾斜した側面にガス流れ８１が流れやすくなる。よって、戻り流れ８２の影響を受け難くなり、テーパー部２２２に設けた導入穴２２０に被測定ガスが速やかに導入されやすくなる。 In this example, since the tapered portion 222 is provided, the gas flow 81 easily flows on the inclined side surface of the inner cover 22. Therefore, it becomes difficult to be influenced by the return flow 82, and the gas to be measured is easily introduced into the introduction hole 220 provided in the tapered portion 222.

さらに、本例にかかる構成では、テーパー部２２２を設けることで、外側カバー２１の導入穴２１０と内側カバー２２の導入穴２２０の径方向距離が小さくなるため、被測定ガスが速やかに導入されやすくなる。
その他は実施形態例１と同様の作用効果を有する。
なお、上記内側カバー２２のテーパー部２２２であるが、図９に示すごとく、底部まで設けることもできる。 Furthermore, in the configuration according to this example, by providing the tapered portion 222, the radial distance between the introduction hole 210 of the outer cover 21 and the introduction hole 220 of the inner cover 22 is reduced, so that the gas to be measured is easily introduced quickly. Become.
The other effects are the same as those of the first embodiment.
In addition, although it is the taper part 222 of the said inner side cover 22, as shown in FIG. 9, it can also provide to a bottom part.

参考例４
本例は、図１０に示すごとく、内側カバー２２に段部２２１が設けてある被測定ガス側カバー２について説明する。
図１０に示すごとく、外側カバー２１はフランジより下方から底部２１８まで径が一定であるストレート部２１３を有する。内側カバー２２は径方向内側に凹む段部２２１を有する。内側カバー２２の導入穴２２０は段部２２１よりも基端側に設けてある。
その他詳細な構成は実施形態例１と同様である。 Reference example 4
In this example, as shown in FIG. 10, a measured gas side cover 2 in which a step portion 221 is provided on the inner cover 22 will be described.
As shown in FIG. 10, the outer cover 21 has a straight portion 213 whose diameter is constant from the bottom to the bottom 218 from the flange. The inner cover 22 has a step portion 221 that is recessed radially inward. The introduction hole 220 of the inner cover 22 is provided on the proximal end side with respect to the step portion 221.
Other detailed configurations are the same as those of the first embodiment.

本例は、段部２２１によって内側カバー２２が径方向に凹み、凹んだ基端側に導入穴２２０が設けてある。そのため、導入穴２２０を設けた部分のクリアランスが大きくなり、戻り流れ８２の影響を受け難い状態で、被測定ガスを被測定ガス室に導入することができる。
その他は、実施形態例１と同様の効果を有する。 In this example, the inner cover 22 is recessed in the radial direction by the step portion 221, and the introduction hole 220 is provided on the recessed base end side. Therefore, the clearance at the portion where the introduction hole 220 is provided becomes large, and the gas to be measured can be introduced into the gas chamber to be measured in a state where it is not easily affected by the return flow 82.
The other effects are the same as those of the first embodiment.

参考例５
本例は、図１１に示すごとく、外側及び内側カバー２１、２２の双方に段部２１１、２２１が設けてある被測定ガス側カバー２について説明する。
図１１に示すごとく、外側カバー２１は段部２１１を有する。導入穴２１０は段部２１１より先端側に設けてある。また、内側カバー２２も突き当たり部分となる段部２２１を有する。段部２２１における天井面２２４に対し、導入穴２２０は設けてある。また、段部２２１よりは、段部２１１のほうがより先端側に存在する。
その他詳細な構成は実施形態例１と同様である。 Reference Example 5
In this example, as shown in FIG. 11, the measured gas side cover 2 in which step portions 211 and 221 are provided on both the outer and inner covers 21 and 22 will be described.
As shown in FIG. 11, the outer cover 21 has a stepped portion 211. The introduction hole 210 is provided on the tip side from the step portion 211. Further, the inner cover 22 also has a stepped portion 221 that becomes a butting portion. An introduction hole 220 is provided in the ceiling surface 224 of the step portion 221. Further, the stepped portion 211 is located on the tip side more than the stepped portion 221.
Other detailed configurations are the same as those of the first embodiment.

上記天井面２２４はガス流れ８１に交わる方向に形成され、ガス流れは天井面２２４に対して突き当たる。この天井面２２４に導入穴２２０が設けてあるため、戻り流れが生じることなく、被測定ガスは速やかに導入穴２２０に入ることができる。
その他詳細は実施形態例１と同様の作用効果を有する。 The ceiling surface 224 is formed in a direction intersecting with the gas flow 81, and the gas flow strikes the ceiling surface 224. Since the introduction hole 220 is provided in the ceiling surface 224, the gas to be measured can quickly enter the introduction hole 220 without causing a return flow.
Other details have the same effects as the first embodiment.

参考例６
本例は、図１２に示すごとく、外側カバー２１にテーパー部２１２が設けてある被測定ガス側カバー２である。
図１２に示すごとく、外側カバー２１はフランジ部の下方から設けられたテーパー部２１２を有する。また、テーパー部２１２は途中でストレート部２１３に切りかわる。
また、内側カバー２２は、全体がストレート部２２３である。
その他詳細な構成は実施形態例１と同様である。 Reference Example 6
This example is a measured gas side cover 2 in which a tapered portion 212 is provided on the outer cover 21 as shown in FIG.
As shown in FIG. 12, the outer cover 21 has a tapered portion 212 provided from below the flange portion. Further, the tapered portion 212 is switched to the straight portion 213 in the middle.
The entire inner cover 22 is a straight portion 223.
Other detailed configurations are the same as those of the first embodiment.

本例にかかる構成では、テーパー部２２１を設けることで、導入穴２２０でのクリアランスを大きくすることができ、ガス流れ８１に対する戻り流れ８２の影響を小さくすることができる。よって、被測定ガスは被測定ガス室に速やかに入ることができる。
その他、実施形態例１と同様の作用効果を有する。 In the configuration according to this example, by providing the tapered portion 221, the clearance in the introduction hole 220 can be increased, and the influence of the return flow 82 on the gas flow 81 can be reduced. Therefore, the gas to be measured can quickly enter the gas chamber to be measured.
In addition, it has the same effects as the first embodiment.

参考例７
本例は、図１３に示すごとく、外側カバー２１に段部２１１、内側カバー２２に段部２２１が設けてある被測定ガス側カバー２である。
図１３に示すごとく、本例において、外側カバー２１は径方向外側に突出する段部２１１が設けてあり、内側カバー２２は径方向内側に凹む段部２２１が設けてある。また、内側カバー２２はフランジ部の下方が径方向内側に凹んだ状態にあり、同図より明らかであるが、内側カバー２２の基端側全体が凹んだような状態である。この凹んだ部分に導入穴２２０が設けてある。
その他詳細な構成は実施形態例１と同様である。 Reference Example 7
In this example, as shown in FIG. 13, the measured gas side cover 2 is provided with a step portion 211 on the outer cover 21 and a step portion 221 on the inner cover 22.
As shown in FIG. 13, in this example, the outer cover 21 is provided with a step portion 211 that protrudes radially outward, and the inner cover 22 is provided with a step portion 221 that is recessed radially inward. Further, the inner cover 22 is in a state where the lower portion of the flange portion is recessed inward in the radial direction, and as is apparent from the drawing, the entire proximal end side of the inner cover 22 is recessed. An introduction hole 220 is provided in the recessed portion.
Other detailed configurations are the same as those of the first embodiment.

本例は、外側カバーの段部２１１と内側カバーの段部２２１とによって、内側の導入穴２２０が設けてある付近のクリアランスが比較的大きくなっている。そのため、ガス流れ８１と戻り流れ８２との間隔が離れ、ガス流れ８１に対する戻り流れ８２の影響を小さくすることができる。よって、被測定ガスは被測定ガス室に速やかに入ることができる。
その他、実施形態例１と同様の作用効果を有する。 In this example, the outer cover step portion 211 and the inner cover step portion 221 have a relatively large clearance near the inner introduction hole 220. Therefore, the gap between the gas flow 81 and the return flow 82 is increased, and the influence of the return flow 82 on the gas flow 81 can be reduced. Therefore, the gas to be measured can quickly enter the gas chamber to be measured.
In addition, it has the same effects as the first embodiment.

実施形態例２
本例は、図１４、図１５に示すごとく、外側カバー２１に段部２１１、溝部２１５、内側カバーにテーパー部２２２が設けてある被測定ガス側カバー２である。
図１４、図１５に示すごとく、外側カバー２１は径方向内側に凹む段部２１１が設けてあり、段部２１１よりも先端側に長軸方向がガスセンサの軸方向と平行となるように設けた楕円形の導入穴２１０が周方向に等間隔に６つ設けてある。これら導入穴２１０の間に、径方向内側に凹んだ断面形状が三角の（図１５参照）溝部２１５を６つ設けた。 Embodiment 2
In this example, as shown in FIGS. 14 and 15, the measured gas side cover 2 is provided with a step portion 211, a groove portion 215 on the outer cover 21, and a tapered portion 222 on the inner cover.
As shown in FIGS. 14 and 15, the outer cover 21 is provided with a step portion 211 that is recessed inward in the radial direction, and is provided on the tip side of the step portion 211 so that the major axis direction is parallel to the axial direction of the gas sensor. Six elliptical introduction holes 210 are provided at equal intervals in the circumferential direction. Between the introduction holes 210, six groove portions 215 having a triangular cross-sectional shape (see FIG. 15) recessed radially inward are provided.

内側カバー２２はフランジ部２９よりすぐ下にテーパー部２２２を有する。そして、内側カバー２２は中央付近の切替部２２６においてテーパー部２２２が終了し、切替部２２６より先端側は径が一定のストレート部２２３である。
その他詳細な構成は実施形態例１と同様である。 The inner cover 22 has a tapered portion 222 immediately below the flange portion 29. The inner cover 22 has a tapered portion 222 at the switching portion 226 near the center, and a straight portion 223 having a constant diameter on the tip side of the switching portion 226.
Other detailed configurations are the same as those of the first embodiment.

本例において、段部２１１によってクリアランスを大きくすることができるため、ガス流れ８１と戻り流れ８２との間隔を遠ざけて、ガス流れ８１に戻り流れ８２からの影響を受け難く、ガス流れ８１がテーパー部２２２に沿って流れることでも、戻り流れ８２の影響を受け難くできる。よって、テーパー部２２２に設けた内側カバー２２の導入穴２２０へ戻り流れ８２の影響を受け難いまま、被測定ガスを導入することができる。
さらに、上記溝部２１５によって、ガス流れ８１を整流して、内側カバー２２の導入穴２２０に向かいやすくすることができる。
その他は実施形態例１と同様の作用効果を有する。 In this example, since the clearance can be increased by the step portion 211, the distance between the gas flow 81 and the return flow 82 is increased, and the gas flow 81 is hardly affected by the return flow 82. The gas flow 81 is tapered. Even flowing along the portion 222 can be less affected by the return flow 82. Therefore, the gas to be measured can be introduced without being affected by the flow 82 returning to the introduction hole 220 of the inner cover 22 provided in the tapered portion 222.
Further, the gas flow 81 can be rectified by the groove 215 so as to be easily directed to the introduction hole 220 of the inner cover 22.
The other effects are the same as those of the first embodiment.

実施形態例１における、積層型のガスセンサ素子を設けたガスセンサの断面説明図。Sectional explanatory drawing of the gas sensor which provided the laminated | stacked type gas sensor element in Embodiment 1. FIG. 実施形態例１における、被測定ガス側カバーの要部説明図。The principal part explanatory drawing of the to-be-measured gas side cover in Embodiment 1. FIG. 実施形態例１における、被測定ガス側カバーの断面説明図。Sectional explanatory drawing of the to-be-measured gas side cover in Embodiment 1. FIG. 実施形態例１における、性能評価の試験結果を示す線図。The diagram which shows the test result of performance evaluation in Embodiment Example 1. FIG. 実施形態例１における、コップ型のガスセンサ素子を設けたガスセンサの断面説明図。Sectional explanatory drawing of the gas sensor which provided the cup-type gas sensor element in Example 1 of an embodiment. 参考例１における、大クリアランス部分とこれよりも狭い小クリアランス部分とが形成された被測定ガス側カバーの断面説明図。Sectional explanatory drawing of the to-be-measured gas side cover in which the large clearance part and the narrower clearance part narrower than this in Reference Example 1 were formed. 参考例２における、外側カバーに段部が設けてある被測定ガス側カバーの要部説明図。The principal part explanatory drawing of the to-be-measured gas side cover in which the step part is provided in the outer side cover in the reference example 2. FIG. 参考例３における、内側カバーにテーパー部が設けてある被測定ガス側カバーの要部説明図。The principal part explanatory drawing of the to-be-measured gas side cover in which the taper part is provided in the inner cover in the reference example 3. FIG. 参考例３における、内側カバーにテーパー部が先端側まで設けてある被測定ガス側カバーの要部説明図。The principal part explanatory drawing of the to-be-measured gas side cover in which the taper part is provided in the inner side cover in the reference example 3 to the front end side. 参考例４における、内側カバーに段部が設けてある被測定ガス側カバーの要部説明図。The principal part explanatory drawing of the to-be-measured gas side cover in which the step part is provided in the inner cover in the reference example 4. FIG. 参考例５における、外側及び内側カバーの双方に段部が設けてある被測定ガス側カバーの要部説明図。The principal part explanatory drawing of the to-be-measured gas side cover in which the step part is provided in both the outer side and the inner side cover in the reference example 5. FIG. 参考例６における、外側カバーにテーパー部が設けてある被測定ガス側カバーの要部説明図。The principal part explanatory drawing of the to-be-measured gas side cover in which the taper part is provided in the outer side cover in the reference example 6. FIG. 参考例７における、外側カバーに段部、内側カバーに段部が設けてある被測定ガス側カバーの要部説明図。The principal part explanatory drawing of the to-be-measured gas side cover in which the step part is provided in the outer cover and the inner cover in the reference example 7. FIG. 実施形態例２における、外側カバーに溝部を設けた被測定ガス側カバーの要部説明図。The principal part explanatory drawing of the to-be-measured gas side cover which provided the groove part in the outer side cover in Example 2 of an embodiment. 実施形態例２における、図１４に示した溝部を設けた外側カバーの底部の説明図。Explanatory drawing of the bottom part of the outer side cover which provided the groove part shown in FIG. 従来にかかる被測定ガス側カバーの要部説明図。Explanatory drawing of the principal part of the to-be-measured gas side cover concerning the former. 従来にかかる被測定ガス側カバーの断面説明図。Cross-sectional explanatory drawing of the to-be-measured gas side cover concerning the past.

Explanation of symbols

１．．．ガスセンサ、
２．．．被測定ガス側カバー、
２１．．．外側カバー、
２２．．．内側カバー、
２００．．．被測定ガス室、
２１１、２２１．．．段部、
２１２、２２２．．．テーパー部、 1. . . Gas sensor,
2. . . Gas cover to be measured,
21. . . Outer cover,
22. . . Inner cover,
200. . . Gas chamber to be measured,
211, 221. . . Step,
212, 222. . . Taper,

Claims

A gas sensor element for detecting a specific gas concentration in the gas to be measured is inserted into the cylindrical housing, the atmosphere side cover at the base end side of the housing, and the gas side cover to be measured including the inner cover and the outer cover at the distal end side In the gas sensor provided with
A gas chamber to be measured is formed inside the inner cover,
The inner cover and the outer cover each have an introduction hole for introducing a gas to be measured into the gas chamber to be measured, and are provided in the inner cover rather than the introduction hole provided in the outer cover. The introduction hole exists on the more proximal side,
From the introduction hole provided in the inner cover while forming a gas flow that is introduced from the introduction hole provided in the outer cover and the clearance between the outer cover and the inner cover is directed from the distal end side to the proximal end side, The measured gas side cover is configured so that the measured gas is introduced into the measured gas chamber,
Provide a step portion whose diameter is switched on the outer cover and / or the inner cover,
The outer cover and / or at least part of the side surface of the inner cover is configured so that the diameter decreases from the proximal end side toward the distal end side, or the diameter decreases from the distal end side toward the proximal end side. Taper part
The gas sensor according to claim 1, wherein the introduction hole is provided in a portion where the tapered portion of the inner cover is provided.

In Claim 1, the said outer cover is provided with the step part from which the magnitude | size of a diameter switches, The said inner cover is toward the front end side from the base end side in the base end side rather than the step part provided in the said outer cover. A tapered portion having a small diameter and a straight portion having a constant diameter on the tip side of the tapered portion, and the inner cover has the introduction hole formed in the portion provided with the tapered portion. Provided,
A clearance C1 between the outer cover and the inner cover in a portion where the step portion of the outer cover is provided;
A gas sensor characterized in that a relationship of C1> X is established between the straight portion of the inner cover and the clearance X between the outer cover facing the straight portion.

3. The gas sensor according to claim 1, wherein the outer cover has a groove that is recessed radially inward.