JPH09304147A - Measuring element for thermal air flowmeter and thermal air flowmeter containing the same - Google Patents

Measuring element for thermal air flowmeter and thermal air flowmeter containing the same

Info

Publication number
JPH09304147A
JPH09304147A JP12018896A JP12018896A JPH09304147A JP H09304147 A JPH09304147 A JP H09304147A JP 12018896 A JP12018896 A JP 12018896A JP 12018896 A JP12018896 A JP 12018896A JP H09304147 A JPH09304147 A JP H09304147A
Authority
JP
Grant status
Application
Patent type
Prior art keywords
part
substrate
body
resistor
thermal
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP12018896A
Other languages
Japanese (ja)
Inventor
Tadashi Isono
Kaoru Uchiyama
Izumi Watanabe
Masamichi Yamada
内山  薫
雅通 山田
渡辺  泉
磯野  忠
Original Assignee
Hitachi Car Eng Co Ltd
Hitachi Ltd
株式会社日立カーエンジニアリング
株式会社日立製作所
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date

Links

Abstract

PROBLEM TO BE SOLVED: To provide a measuring element, for a thermal air flowmeter, which improves the thermal insulation of a support body from a resistor, which is excellent in a temperature characteristic and whose accuracy is high. SOLUTION: A measuring element for a thermal air flowmeter is constituted of a heating resistor 2 which is installed parallely in the flow direction of an air current 8 and which is formed in a heating-body film formation part 6 ion a substrate 1, of a resistor 3, for temperature compensation, which is formed in a compensating-body film formation part 7 on the substrate and of a plurality of electrode terminals 9 and decoration electrodes 10 which come into contact with a support body 5, which are formed in a substrate support part 11 supporting the substrate 1 and which fetch electric signals from the respective resistors. The heating-body film formation part 6 and the compensating-body film formation part 7 are arranged so as to be separated from each other on the downstream side and the upstream side with reference to the flow direction by sandwiching a first slit 16, and a second slit 15 which adjusts heat conduction to the resistor 3, for temperature compensation, from the end of the substrate support part is formed between the resistor 3 for temperature compensation and the substrate support part 11.

Description

【発明の詳細な説明】 DETAILED DESCRIPTION OF THE INVENTION

【0001】 [0001]

【発明の属する技術分野】本発明は、熱式空気流量計用測定素子に係り、特に内燃機関の吸入空気量を測定するのに好適な熱式空気流量計用測定素子及び熱式空気流量計に関する。 The present invention relates to relates to a thermal type air flow meter for measuring element, especially suitable thermal air flow meter for measuring element and the thermal type air flow meter for measuring the intake air amount of the internal combustion engine on.

【0002】 [0002]

【従来の技術】従来より自動車などの内燃機関の電子制御燃料噴射装置に設けられ吸入空気量を測定する空気流量計として、熱式のものが質量空気量を直接検知できることから主流となってきており、特に、製造コストを低減するために基板に薄膜抵抗体を成膜した薄膜型の熱式空気流量計が主流になりつつある。 As an air flow meter for measuring the intake air amount is provided to the ART electronically controlled fuel injection system for an internal combustion engine such as conventionally automobiles, and those of thermal type is becoming the mainstream because it can detect a mass air quantity directly cage, in particular, the thermal type air flow meter of a thin film type by forming a thin film resistor on the substrate in order to reduce the manufacturing cost is becoming mainstream. 薄膜型の熱式空気流量計としては、特開昭63−134920号公報、特開平1−185416号公報に開示されたものがある。 The thermal air flow meter of a thin film type, JP 63-134920, JP is disclosed in JP-A-1-185416. 上記公報に記載の技術は、薄膜型であることから製造コストはある程度低減されているが、吸入空気の逆流の影響により誤差を生ずるもの、また熱式空気流量計として温度特性に関して考慮されていないという問題があった。 The technique described in the above publication, although the manufacturing cost is reduced to some extent because it is a thin film type, those caused an error due to the influence of reverse flow of intake air, also does not consider the temperature characteristics as thermal air flow meter there is a problem in that.

【0003】 [0003]

【発明が解決しようとする課題】上記従来技術には次のような課題がある。 The THE INVENTION to be solved INVENTION The above prior art has the following problems. これについて、特開昭63−134 In this regard, JP-A-63-134
920号公報(第2図)に記載の従来技術の薄膜型の熱式空気流量計用測定素子の鳥瞰図である図12を参照し説明する。 920 JP reference to FIG. 12 is a perspective view of a prior art thin film type thermal air flow meter for measuring device according to (Fig. 2) will be described. 図において、1がセラミック等よりなる絶縁基板、Rkが補償抵抗(温度補償用)、Rsが加熱抵抗、R In the figure, the insulating substrate 1 is made of ceramic or the like, Rk compensation resistor (temperature compensating), Rs is heated Resistance, R
hが測定抵抗、8が吸入空気の流れ方向、5が支持体、 h is the measured resistance, 8 the flow direction of the intake air, 5 support,
16がスリットで基板1が上流側部分29と下流側30 16 downstream 30 the substrate 1 and the upstream portion 29 at the slit
に分割されている。 It is divided into. この従来例は傍熱型の熱式空気流量計の構成になっている、すなわち加熱抵抗(Rs)は基板1を介して反対側の面に形成された測定抵抗(Rh)を加熱(傍熱)し、上流側の基板29に形成され空気温度に対応する補償抵抗(Rk)より、上記測定抵抗(Rh)の温度が一定温度高くなるように制御されており加熱抵抗(R This conventional example has a structure of the thermal type air flow meter indirectly heated, or heating resistor (Rs) is heated measuring resistor formed on the opposite side through the substrate 1 (Rh) (indirect heating ) and, from the upstream side is formed on the substrate 29 of the compensation resistance corresponding to the air temperature (Rk), and heating resistors is controlled so that the temperature of the measuring resistor (Rh) is high constant temperature (R
s)に流す電流値より空気流量を検出するものである。 Than the current value flowing in s) is used to detect an air flow rate.

【0004】スリット16は、加熱抵抗(Rs)からの熱伝導を防ぎ空気温度となるべき補償抵抗(Rk)の温度上昇を防止するためのものである。 [0004] slit 16 is for preventing the temperature rise of the compensating resistors to be the air temperature to prevent heat conduction from the heating resistor (Rs) (Rk). このような構成の従来技術では、逆流の空気が流れた場合、逆流を検知できないとともに、空気温度となるべき補償抵抗(Rk)がスリット16の存在にもかかわらず、逆流空気の熱伝達により加熱抵抗(Rs)の熱が伝わり温度が上昇し、空気流量測定の誤差を伴う。 In such a configuration of the conventional art, if the backflow of air flows, with not detect a reverse flow, compensating resistors to be the air temperature (Rk) despite the presence of the slit 16, heated by heat transfer backflow air heat is transferred temperature of the resistance (Rs) increases, accompanied by an error of the air flow measurement. また、支持体5が、内燃機関等の熱により空気温度より上昇した場合、上記補償抵抗体(R Moreover, the support 5, when raised from the air temperature by the heat of the internal combustion engine or the like, the compensation resistor (R
k)に熱が伝わり、温度特性が劣化することがある。 Heat is transferred to the k), the temperature characteristics may be deteriorated.

【0005】次に、逆流を検知する従来例としての上記特開平1−185416号公報に関する課題について、 [0005] Next, the issues related to the Japanese Patent 1-185416 discloses as a conventional example to detect a reverse flow,
該公報に記載の第4図である図13により以下に説明する。 Said patent is described below with FIG. 13 is a fourth diagram according to report. 図13は従来の逆流を検知する熱式空気流量計用測定素子を示す平面図である。 Figure 13 is a plan view showing a thermal type air flow meter for measuring element for detecting a conventional backflow. 図において、1がセラミック等の熱伝導率の大きい電気絶縁材料からなる基板、2 In the figure, a substrate 1 is made of high electrically insulating material thermal conductivity such as ceramic, 2
a,2bが発熱抵抗体、3a,3bが温度補償用抵抗体、9が電極端子、16がスリット、8が空気の流れ方向である。 a, 2b are heat generating resistor, 3a, 3b the temperature compensating resistor, 9 electrode terminal, 16 is a slit, 8 is a flow direction of the air. このような構成では発熱抵抗体2a,2bと温度補償用抵抗体3a,3bの間にスリット16を設けているが、両抵抗体間が近接していると共に、熱伝導率の大きい基板1がスリット16の両端部で繋がっているために、発熱抵抗体2a,2bから温度補償用抵抗体3 Heating resistor 2a in such a configuration, 2b and the temperature compensating resistor 3a, although the slit 16 is provided between 3b, with between both resistors are in close proximity, a large substrate 1 in thermal conductivity to are connected at both ends of the slit 16, the heating resistor 2a, a temperature compensation resistor 3 from 2b
a,3bへ熱が容易に移動し熱絶縁が十分でないため、 For a, heat is easily moved thermally insulated to 3b not sufficient,
空気流量の計測精度を悪化させている。 Exacerbating the measurement accuracy of the air flow rate.

【0006】また、発熱抵抗体2a,2b及び温度補償用抵抗体3a,3bからの電気信号は、基板1の両端に位置する電極端子9より取り出され、基板1の両端で支持され、且つ図示していない外部回路に接続される両端支持構造となっている。 Further, the heating resistors 2a, 2b and the temperature compensating resistor 3a, the electrical signals from 3b is taken out from the electrode terminals 9 located at both ends of the substrate 1 is supported at both ends of the substrate 1, and FIG. and has a both ends support structure connected to an external circuit not shown. 上記従来技術で記したように、 As noted in the prior art described above,
このような構成では支持体(該特開平1−185416 The support in this configuration (該特 Hei 1-185416
号公報の第2図参照)が内燃機関等の熱により空気温度より上昇した場合、両端の支持体からの熱伝導が無視できず温度補償用抵抗体3a,3bの温度が空気温度より上がるために温度特性に問題がある。 If No. cf. FIG. 2 of JP) rises above the air temperature by the heat of the internal combustion engine or the like, thermal conduction is negligible not temperature-compensating resistor 3a from the support at both ends, the temperature of 3b rises than air temperature there is a problem with the temperature characteristics.

【0007】従って、本発明の目的は、抵抗体同志の熱絶縁を改善し、温度特性の優れた高精度の熱式空気流量計用素子及びそれを含む熱式空気流量計を提供することにある。 Accordingly, it is an object of the present invention, the thermal insulation of the resistor comrades improved, to provide an excellent precision of the thermal type air flow meter element and the thermal air flow meter including the same temperature characteristic is there.

【0008】 [0008]

【課題を解決するための手段】上記の目的は、被測定流体の流れ方向に並設されている、基板の発熱体成膜部位に成膜された発熱抵抗体および前記基板の補償体成膜部位に成膜された温度補償用抵抗体と、前記発熱抵抗体及び前記温度補償用抵抗体から電気信号を取り出す為の、 The purpose of the Means for Solving the Problems] are arranged side by side in the flow direction of the fluid to be measured, the heating resistor and compensating body deposition of the substrate that has been deposited on the heating element film formation region of the substrate a temperature compensation resistor which is formed at the site, for taking out the electric signal from the heating resistor and the temperature compensating resistor,
前記発熱体成膜部位及び前記補償体成膜部位を除いた前記基板の部位であって当該基板が支持される基板支持部位に成膜された複数の電極とから、前記被測定流体の流量を検出する検出回路として構成された熱式空気流量計用測定素子において、前記発熱体成膜部位と前記補償体成膜部位とは、前記基板に形成された第一のスリットを挟んで、前記被測定流体の流れ方向に対して下流側と上流側に各々離間配置され、且つ、前記温度補償用抵抗体と前記基板支持部位間に、前記基板支持部位端から前記温度補償用抵抗体への熱伝導を調整する為の第二のスリットを設けることにより達成される。 And a plurality of electrodes formed on the substrate supporting portion to which the substrate is supported by a portion of the substrate except for the heating element film formation region and the compensation member film formation region, the flow rate of the fluid to be measured the thermal type air flow meter for measuring element configured as a detection circuit for detecting that, the heating element film formation region and said compensator deposition sites across the first slit formed in the substrate, the object are respectively spaced downstream and upstream relative to the direction of flow of the measurement fluid, and, between the substrate supporting portion and the temperature compensating resistor, the heat from the substrate supporting portion end to the temperature compensating resistor It is achieved by providing the second slit for adjusting the conductivity.

【0009】更には、第二のスリットの形状は、前記基板を伝わる熱伝導における前記基板支持部位端から前記発熱抵抗体に至る熱抵抗と、前記基板支持部位端から前記温度補償用抵抗体に至る熱抵抗とがほぼ同じになるようにして定められていることが望ましい。 Furthermore, the shape of the second slits has a thermal resistance leading to the heating resistors from the substrate supporting portion end in the heat conduction transferred to the substrate, the temperature compensating resistor from the substrate supporting portion end it is desirable that the thermal resistance reaches is defined as approximately the same.

【0010】また、上記目的を達成する熱式空気流量計は、請求項1ないし請求項3のいずれか1項記載の熱式空気流量計用測定素子を含み被測定流体の流量を測定するものである。 Further, those thermal air flow meter to achieve the above object, the include thermal air flow meter for measuring element according to any one of claims 1 to 3 for measuring the flow rate of the fluid to be measured it is.

【0011】本発明によれば、基板支持部位端からの伝導熱の影響が隔絶されるので、温度特性の優れた高精度の熱式空気流量計用素子及びそれを含む熱式空気流量計が提供される。 According to the present invention, the influence of the conduction heat from the substrate support portion end is isolated, excellent precision of the thermal type air flow meter element and the thermal air flow meter including the same temperature characteristic It is provided.

【0012】 [0012]

【発明の実施の形態】以下、本発明の実施の形態について、図面を参照し説明する。 BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention, with reference to the drawings. 図1は、本発明による第一の実施例の熱式空気流量計用測定素子を示す平面図である。 Figure 1 is a plan view showing a thermal type air flow meter for measuring element of the first preferred embodiment of the present invention. 熱式空気流量計用測定素子は、基板1と、該基板1 Thermal air flow meter for measuring element comprises a substrate 1, the substrate 1
の空気流8の下流側に配置され成膜された発熱抵抗体2 Heating resistor 2 which is formed is disposed on the downstream side of the airflow 8
と、上流側に配置され成膜された温度補償用抵抗体3 When the temperature compensating resistor 3 which is formed is disposed on the upstream side
と、温度補償用抵抗体3の抵抗値を調整するための抵抗値補償用抵抗体4と、発熱抵抗体及び温度補償用抵抗体から電気信号を取り出すための電極としての引出電極1 When lead electrodes as an electrode for taking out the resistance value compensation resistor 4 for adjusting the resistance value of the temperature compensation resistor 3, the electric signal from the heating resistor and the temperature compensating resistor 1
0a,10b,10c,10dと電極端子9a,9b, 0a, 10b, 10c, 10d and the electrode terminals 9a, 9b,
9c,9dとから構成される。 9c, composed of a 9d.

【0013】そして、基板1は、発熱抵抗体2が成膜される発熱体成膜部位6と、温度補償用抵抗体3が成膜される補償体成膜部位7と、該発熱体成膜部位及び補償体成膜部位を除いた基板の部位であって、支持体5に当接して基板1が支持される基板支持部位11とを有し、且つ、第一のスリット16、第二のスリット15を有している。 [0013] Then, the substrate 1 is provided with a heating element film formation region 6 where the heating resistors 2 is deposited, a compensator film formation region 7 where the temperature compensating resistor 3 is formed, heating elements deposited a portion of the substrate excluding the site and compensator film formation region, in contact with the support 5 and a substrate support portion 11 to the substrate 1 is supported, and a first slit 16, a second and a slit 15. そして、図1の破線で図示されている部分は、基板1を支持する支持体5を示す仮想線である。 A portion depicted by a broken line in FIG. 1 is a virtual line showing the supporting member 5 for supporting the substrate 1.

【0014】また、発熱体成膜部位6(発熱抵抗体2)と補償体成膜部位7(温度補償用抵抗体3)との位置関係は、被測定流体としての空気流8の流れ方向に対して上流側と下流側の位置関係(前と後方向の関係)および左右の位置関係(流れに対して垂直方向の位置関係)に離間配置されて(ずれて)いるものとする。 Further, the positional relationship of the heat generating element film formation region 6 (the heating resistor 2) and the compensator film formation region 7 (temperature compensating resistor 3), the flow direction of the air flow 8 as a fluid to be measured positional relationship between the upstream and downstream (the relationship of the front and rear direction) and lateral positional relationship is spaced (positional relationship in the vertical direction relative to the flow) (deviation) shall have for. すなわち、例えば図1に図示したように、発熱体成膜部位6が下流左側に配置されれば、補償体成膜部位7は上流右側に配置されるように、空気流8の流れ方向に対し、前後左右に段違いでずれた位置関係にあるものとする。 That is, as shown in FIG. 1, for example, if the heating element film formation region 6 is located downstream the left, the compensator film formation region 7 to be positioned upstream right, with respect to the flow direction of the air flow 8 , it is assumed that a positional relationship shifted by uneven in all directions. これは、発熱抵抗体2と温度補償用抵抗体3とが空気流8の流れ方向に対し重ならないようにし、且つ、発熱抵抗体2と温度補償用抵抗体3との間を出来るだけ遠くに離し、熱絶縁の向上を図るためのものである。 This is because the heating resistor 2 and the temperature compensation resistor 3 so as not to overlap with respect to the flow direction of the air flow 8, and, between the heating resistor 2 and the temperature compensation resistor 3 can only far away, it is intended to improve the thermal insulation.

【0015】更に、上記の段違いに且つずらして配置された発熱体成膜部位6と補償体成膜部位7との間に、第一のスリット16を、また、温度補償用抵抗体3と基板支持部位11との間に、第二のスリット15を設ける。 Furthermore, between the heating element film formation region 6 and the compensator film formation region 7 which is staggered above different levels and the first slit 16, also, a temperature compensating resistor 3 substrate between the support portion 11 is provided with a second slit 15.
このスリット15,16は、発熱抵抗体2と温度補償用抵抗体3間をさらに隔離するので、さらに熱絶縁を良くする。 The slits 15 and 16, because further isolate between the heating resistor 2 and the temperature compensation resistor 3, further improve the thermal insulation. 特に、定温度制御をするブリッジ回路構成においては、温度補償用抵抗体3の発熱を防止するために、温度補償用抵抗体3の電気抵抗は発熱抵抗体2に比較して大きく設定される。 In particular, in a bridge circuit configuration for a constant temperature control, to prevent heating of the temperature compensating resistor 3, the electric resistance of the temperature compensating resistor 3 is set larger as compared with the heating resistor 2. このため、大きい電気抵抗の温度補償用抵抗体3を形成する前記補償体成膜部位7の基板幅は、前記発熱体成膜部位6の基板幅より大きくなる。 Therefore, the substrate width of the compensator film formation region 7 to form the temperature compensating resistor 3 large electrical resistance is larger than the width of the substrate of the heating element film formation region 6. 従って、温度補償用抵抗体3と基板支持部位11間に形成される第二のスリット15は、前記温度補償用抵抗体3 Thus, the second slit 15 formed between the temperature compensating resistor 3 substrate support portion 11, the temperature compensating resistor 3
の熱絶縁を図る上で効果的な役割を担っている。 It plays an effective role in achieving thermal insulation. また、 Also,
第一のスリット16を、図1に示す破線で図示されている基板支持部位11の境界5aに達するまで、流れ方向の左右方向に延長することによって、基板1を介して伝達される発熱抵抗体2の熱が、支持体5の方へ放熱されるので、温度補償用抵抗体3への熱影響が低減され、更に測定精度を向上させることが出来る。 A first slit 16, until it reaches the boundary 5a of the substrate support portion 11, which is shown by a broken line shown in FIG. 1, by extending in the lateral direction of the flow direction, the heat generating resistor that is transmitted through the substrate 1 2 of heat, because the heat is radiated towards the substrate 5, the thermal influence on the temperature compensating resistor 3 is reduced, it is possible to further improve the measurement accuracy. これは、余分な基板端による熱移動がなくなり、熱伝導路が遮断されるからである。 This eliminates the heat transfer due to the extra substrate end, because the heat conduction path is cut off.

【0016】また、第二のスリット15は、支持体5が内燃機関等の熱により空気温度より上昇した場合、支持体5からの熱伝導で温度補償用抵抗体3の温度に影響を及ぼすのを防止する効果がある。 Further, the second slit 15, the support 5 when raised from the air temperature by the heat of the internal combustion engine or the like, the influence on the temperature of the temperature compensation resistor 3 by heat conduction from the support 5 there is an effect to prevent. 温度補償用抵抗体3の温度が、上記支持体5の熱伝導により空気流8の本来の温度より上昇すると、温度補償用抵抗体3の温度より一定温度高く設定制御(定温度制御)されている発熱抵抗体2に過剰の加熱電流(空気流量信号に相当)が流れ、実際の空気流量値に対して多い(プラス)誤差を示すことになる。 Temperature of the temperature compensating resistor 3, rises above the original temperature of the air flow 8 through the heat conduction of the support 5, is a constant temperature set higher control over the temperature of the temperature compensation resistor 3 (the constant temperature control) excessive heating current to the heating resistor 2 (corresponding to the air flow rate signal) flows, will indicate the actual large relative to the air flow rate value (plus) errors are. 第二のスリット15を設けることにより、支持体5 By providing the second slit 15, support 5
から温度補償用抵抗体3への熱伝導が低減できることから、上記支持体の温度上昇による測定誤差を低減できる。 Because it can heat transfer reduction of the temperature compensating resistor 3 can reduce measurement error due to temperature rise of the support. 更に、上記支持体5からの熱伝導が避けられない場合においても、スリット15の形状を、基板支持部位端5aから温度補償用抵抗体3に至る熱伝導路の熱抵抗 Further, when the heat conduction from the support 5 can not be avoided also, the shape of the slit 15, the thermal resistance of the heat conduction path from the substrate support portion end 5a to the temperature compensating resistor 3
(主に基板1の熱伝導率と基板支持部位端5aから温度補償用抵抗体3に至る基板の断面積と長さにより決まる)を、基板支持部位端5bから発熱抵抗体2に至る熱伝導路の熱抵抗とほぼ同一になるように設定することにより、支持体5の温度上昇の影響を無くすことが出来る。 (Determined mainly by the sectional area of ​​the substrate extending from the thermal conductivity of the substrate 1 and the substrate support portion end 5a to the temperature compensating resistor 3 in length), and heat conduction, from the substrate supporting portion end 5b to the heating resistor 2 by setting the thermal resistance of the road to be substantially the same, it is possible to eliminate the influence of temperature rise of the support 5. これは、支持体5から温度補償用抵抗体3および発熱抵抗体2に至る熱抵抗が同じになると、支持体5から温度補償用抵抗体3と発熱抵抗体2に伝わる熱量および両抵抗体3、2の温度上昇がほぼ同じくなり、定温度制御している両抵抗体3、2の温度上昇がキャンセルし、 This is because when the thermal resistance extending from the support 5 to the temperature compensating resistor 3 and the heating resistor 2 is the same, the amount of heat transferred from the support 5 and the heating resistor 2 temperature compensating resistor 3 and both the resistor 3 , the temperature rise of 2 nearly same, temperature rise of both resistors 3,2 are constant temperature control is canceled,
発熱抵抗体2に流れる加熱電流(空気流量信号)に変化がなくなるためである。 Change the heating current flowing through the heating resistor 2 (air flow rate signal) is because there is no.

【0017】なお、抵抗値補償用抵抗体4は、温度補償用抵抗体3の抵抗値をあらかじめ設定された値に調整するためのものである。 [0017] The resistance value compensation resistor 4 is used to adjust the preset value the resistance value of the temperature compensation resistor 3. 抵抗体2,3,4、引出電極10 Resistor 2,3,4 lead electrodes 10
および電極端子9が形成された基板1は、支持体5によって、機械的に支持されると共に、図示されていない外部回路14と電極端子9とが電気的に接続されるように、一方端が支持される。 And the substrate 1 on which the electrode terminal 9 is formed is by the support 5, while being mechanically supported, as an external circuit 14 and the electrode terminal 9, not shown, are electrically connected, whereas the ends It is supported.

【0018】図2は、図1の熱式空気流量計用測定素子を実装した実施例を示す断面図である。 [0018] FIG. 2 is a sectional view showing an embodiment of mounting the thermal air flow meter for measuring element of FIG. 例えば、内燃機関の吸気通路に実装した熱式空気流量計の実施例を示す断面図である。 For example, a cross-sectional view showing an embodiment of a thermal type air flow meter mounted in an intake passage of the internal combustion engine. 熱式空気流量計は、図のように、熱式空気流量計用測定素子と支持体5と外部回路14とを含み構成される。 Thermal air flow meter, as shown, constituted comprises a thermal air flow meter for measuring element and the support 5 and the external circuit 14. そして吸気通路12の内部にある副通路1 The auxiliary passage 1 in the interior of the intake passage 12
3に熱式空気流量計用測定素子(図では、発熱体成膜部位6、補償体成膜部位7を示す)が配置される。 (In the figure, the heating element film formation region 6, showing the compensator film formation region 7) the measuring element for a thermal type air flow meter 3 is arranged. 外部回路14は支持体5を介して抵抗体2,3に電気的に接続されている。 External circuit 14 are electrically connected to the resistor 2 via a support 5. ここで、通常では吸気空気は8で示された方向に流れており、ある内燃機関の条件によって8とは逆の方向(逆流)に吸気空気が流れる。 Here, in the normal intake air is flowing in the direction indicated by 8, the intake air flows in the opposite direction (reverse flow) and 8 depending on the conditions of a combustion engine.

【0019】図3は、図1の発熱抵抗体2の薄膜パターンを示す拡大図、図4は同じく図1の温度補償抵抗体3 [0019] Figure 3 is an enlarged view showing a thin film pattern of the heating resistor 2 in Figure 1, Figure 4 is also a temperature compensation resistor 3 in FIG. 1
および抵抗値補償用抵抗体4の薄膜パターンを示す拡大図である。 And is an enlarged view showing a thin film pattern of the resistance value compensation resistor 4. 図4において、第二のスリット15は上記したように支持体5から発熱抵抗体2および温度補償用抵抗体3に至るまでの熱抵抗が同じになる様に、所定の形状に形成される。 4, the second slit 15 as the thermal resistance up to the heating resistor 2 and the temperature compensating resistor 3 from the support 5 as described above are the same, is formed into a predetermined shape. また、抵抗値補償用抵抗体4a,4 Further, resistance values ​​compensating resistor 4a, 4
b,4cは、温度補償用抵抗体3の抵抗値を調整するためのもので、抵抗値が所定の値になるように抵抗体4 b, 4c is for adjusting the resistance value of the temperature compensating resistor 3, so that the resistance value is a predetermined value resistor 4
a,4b,4cに並列に接続されている引出電極10a a, 4b, lead electrode 10a which is connected in parallel to 4c
の一部をレーザ等によって焼け切って所望の抵抗値を実現する。 Some of completely burned by a laser or the like to achieve a desired resistance value.

【0020】ここで、基板1は、アルミナ等のセラミックよりなり、空気流量測定の応答速度を高めるために、 [0020] Here, the substrate 1 is made of ceramics such as alumina, in order to increase the response speed of the air flow measurement,
0.05mmから0.15mmの極めて薄い厚みのものから選択される。 They are selected from those from 0.05mm extremely small thickness of 0.15 mm. 発熱抵抗体2、温度補償用抵抗体3及び抵抗値補償用抵抗体4は、白金薄膜よりなり、スパッタ、蒸着などの方法により、0.1ミクロンから2ミクロンの膜厚で、一括して基板1上に着膜される。 The heating resistor 2, a temperature compensating resistor 3 and the resistance value compensation resistor 4 is made of platinum film, sputtering, by a method such as vapor deposition, a thickness of 0.1 to 2 microns microns, collectively substrate is film deposited on 1. その後、ホトエッチングなどの方法により、図3、4に示した形状に形成される。 Thereafter, by a method such as photoetching, it is formed into a shape shown in FIGS.

【0021】なお、『一括して』とは、同一材料を用いて同一行程の同一製造条件で同一膜厚に成膜することを意味している。 [0021] Note that "collectively" means that the deposition in the same thickness under the same production conditions of the same process using the same material. すなわち、図1に示した実施例では、発熱抵抗体2、温度補償用抵抗体3および抵抗値補償用抵抗体4は、基板1上に、同一材料を用いて同一行程の同一製造条件で同一膜厚に成膜される。 That is, in the embodiment shown in FIG. 1, the heating resistor 2, a temperature compensating resistor 3 and the resistance value compensation resistor 4 on the substrate 1, the same in the same production conditions of the same process using the same material It is deposited on the film thickness. これによって、発熱抵抗体2、温度補償用抵抗体3および抵抗値補償用抵抗体4の電気抵抗の温度係数が同じになるので、各抵抗体間の温度特性のばらつきが低減でき、この点からも計測精度が向上する。 Thus, the heating resistor 2, the temperature coefficient of the electrical resistance of the temperature compensating resistor 3 and the resistance value compensation resistor 4 are the same, can be reduced variations in temperature characteristic between the resistors, in this respect also to improve the measurement accuracy.

【0022】また、発熱抵抗体2と温度補償用抵抗体3 [0022] In addition, the heating resistor 2 and the temperature compensation resistor 3
を外部回路に接続するための引出電極10および電極端子9は、発熱を防ぎさらに電気抵抗を少なくするために、抵抗体2、3、4の白金薄膜より厚い白金ー銀合金等の厚膜を、該白金薄膜上に印刷等の方法で形成する。 Lead electrodes 10 and the electrode terminal 9 for connecting to an external circuit, in order to further reduce the electrical resistance to prevent heat generation, the thick film thicker, such as platinum over a silver alloy of a platinum thin-film resistor 2,3,4 , formed by a method such as printing on the platinum thin film.
また、抵抗体2,3,4上には、アルミナ、二酸化珪素やガラス等からなる保護膜(図示していないもの)が形成される。 In addition, over the resistors 2,3,4, alumina, protective film made of silicon dioxide, glass or the like (those not shown) is formed. スリット15,16は、レーザ加工等の方法で形成される。 Slits 15, 16 are formed by the method of laser processing.

【0023】図5は、本発明の第二の実施例の熱式空気流量計用測定素子の平面図である。 FIG. 5 is a plan view of a thermal type air flow meter for measuring element of the second embodiment of the present invention. ここで、図1の第一の実施例と異なるところは、第二のスリット15が、抵抗値補償用抵抗体4と支持体5の間に形成されているところである。 Here, a point different from the first embodiment in FIG. 1, the second slit 15 is about to be formed between the resistance value compensation resistor 4 support 5. このようにスリット15を形成した場合においても、第一の実施例と同様の効果を示す。 Thus even when a slit 15, showing the same effect as the first embodiment. なお、抵抗値補償用抵抗体4の設置は必須ではなく選択されるものである。 Incidentally, the installation of the resistance value compensation resistor 4 are those essential is selected without.

【0024】図6は、本発明の第三の実施例の熱式空気流量計用測定素子の平面図である。 FIG. 6 is a plan view of a thermal type air flow meter for measuring element of the third embodiment of the present invention. ここで、図1の第一の実施例と異なるところは、第三の実施例では空気流量の逆流を検出できるように、発熱抵抗体2、温度補償用抵抗体3および抵抗値補償用抵抗体4を各々一対にしたことである。 Here, a point different from the first embodiment in FIG. 1, as in the third embodiment can detect a reverse flow of the air flow rate, the heating resistor 2, a temperature compensating resistor 3 and the resistance value compensation resistor 4 is each to have a pair of. このように抵抗体をそれぞれ一対としたことにより、例えば、空気の流れが図6の8の方向(順流) By this way the resistor were respectively a pair, for example, the direction of the 8 air flow in FIG. 6 (forward flow)
のときには、上流に設置された発熱抵抗体2aが下流に設置された発熱抵抗体2bに比較してより空気流8に冷やされるためにより大きい加熱電流(空気流量信号)が流れる、一方空気流8と反対方向(逆流)になると、今度は下流側に設置された発熱抵抗体2bのほうが冷却され、 When is larger than the heating current (airflow signal) flows to the heat generating resistor 2a disposed upstream is cooled in an air stream 8 more compared to the heating resistor 2b located downstream, whereas the air stream 8 Conversely becomes a direction (reverse flow), this time towards the heating resistor 2b provided on the downstream side is cooled,
より大きい加熱電流が流れる。 Greater heating current flows. 従って、発熱抵抗体2 Accordingly, the heating resistor 2
a,2bに流れる加熱電流の値を比較すれば空気流の方向(順流か逆流)が、また、各々の加熱電流値より空気流量値が測定出来る。 a, direction (or forward flow reverse flow) of the air flow by comparing the value of the heating current flowing to 2b, but also, the air flow rate value can be measured from each of the heating current. また、スリット15,16を図1の第一の実施例と同様に形成しているので、第一の実施例と同様の効果により測定精度が実現出来る。 Also, since a slit 15, 16 as in the first embodiment of FIG. 1, the measurement accuracy can be realized by the same effect as the first embodiment.

【0025】図7は、本発明の第四の実施例である熱式空気流量計用測定素子の平面図である。 FIG. 7 is a plan view of a thermal type air flow meter for measuring element according to a fourth embodiment of the present invention. この実施例は、図6に示した第三の実施例と異なるのは、 第二のスリット15を抵抗値補償用抵抗体4と支持体5の間に形成したことであり、第三の実施例と同様の効果が実現できる。 This embodiment, the third difference from the embodiment shown in FIG. 6, is that the formation of the second slit 15 between the resistance value compensation resistor 4 of the support 5, a third embodiment the same effect as example can be realized.

【0026】図8は、図6の第三の実施例の測定素子の補償体形成部位7の拡大図である。 [0026] FIG. 8 is an enlarged view of the compensator forming portion 7 of the measuring element of the third embodiment of FIG. 図から、温度補償用抵抗体3は3a,3b、抵抗値補償用抵抗体4は4a,4 From the figure, the temperature compensating resistor 3 3a, 3b, the resistance value compensation resistor 4 4a, 4
b,4c,4d,4e,4fと各々一対形成されている。 b, 4c, 4d, 4e, is 4f and each pair formation. 温度補償用抵抗体3a,3bは図9で示す様に発熱抵抗体2a,2bと各々ブリッジ回路17a,17bを構成する。 Temperature compensating resistor 3a, 3b constitute heat generating resistor 2a as shown in Figure 9, 2b and each bridge circuit 17a, a 17b.

【0027】図9は、逆流を検知できる前記第三及び第四の実施例の外部回路14と抵抗体2a,2b,3a, [0027] Figure 9, the third and fourth embodiments of the external circuit 14 and the resistor 2a can detect reverse flow, 2b, 3a,
3bの電気回路を示す図である。 Is a diagram showing an electric circuit of 3b. 図9を参照し、 本発明の実施例の動作について説明する。 Referring to FIG. 9, the operation of the embodiment of the present invention. 駆動回路17 The drive circuit 17
a,17bは、それぞれ独立した回路であり、電源18 a, 17b are each independent circuits, power source 18
に接続され、別々に空気流量に応じた信号を出力する。 It is connected to separately outputs a signal corresponding to the air flow rate.
駆動回路17aは、上流側に配置された発熱抵抗体2 Driving circuit 17a includes the heating resistor 2 which is arranged on the upstream side
a、温度補償用抵抗体3a、抵抗19a,20aからなるホイーストンブリッジ回路により、ブリッジ中点の電位差が零になるように差動増幅噐22a、トランジスタ21aによって発熱抵抗体2aに流れる加熱電流を調整するように構成されている。 a, the temperature compensating resistor 3a, the resistor 19a, the Wheatstone bridge circuit composed of 20a, the differential amplifier 噐 22a such that a potential difference at the middle point of the bridge becomes zero, the heating current flowing through the heating resistor 2a by the transistor 21a It is configured to adjust. この構成により、発熱抵抗体2aの温度(抵抗値)は空気温度に対応する温度補償用抵抗体3aの温度(抵抗値)より設定されたある一定値 This configuration, temperature (resistance value) of the heating resistor 2a is set a certain value than the temperature of the temperature compensation resistor 3a corresponding to the air temperature (resistance value)
(例えば150℃)高く制御される。 (E.g., 0.99 ° C.) is higher controlled. このとき、発熱抵抗体2aによる空気流量に対応する信号は図中A点の電位である。 At this time, a signal corresponding to the air flow rate by the heat generating resistor 2a is a potential of A in the figure points. 又、駆動回路17bの下流側に配置された発熱抵抗体2bでも同様であり、空気流量に対応する信号は図中B点の電位である。 Further, the same can heat generating resistor 2b disposed on the downstream side of the drive circuit 17b, a signal corresponding to the air flow rate is the potential of FIG point B.

【0028】上記したように、空気の流れの方向は図中のA、B点の電位を電圧比較噐23で比較し、A点の電位が高い場合には順流、B点の電位が高い場合には逆流を判別し方向信号Cとして出力する。 [0028] As described above, the direction of air flow compared A in the figure, the potential at point B in the voltage comparator 噐 23, when the potential at the point A is high forward flow, when the potential at the point B is higher and it outputs the determined reverse flow direction signal C in. また、空気流量値は電圧比較噐23で判別した後、反転スイッチ回路25 Further, after the air flow rate value which is determined by the voltage comparator 噐 23, reversing switch circuit 25
を切り替えることによりA点あるいはB点の高い電位の方を出力信号Dとして出力する。 Outputs towards the high point A or point B potential as an output signal D by switching.

【0029】図10は、熱式空気流量計の動作を説明する図である。 FIG. 10 is a diagram for explaining the operation of the thermal type air flow meter. 図により動作について説明する。 The operation will be described with reference to FIG. 一般に空気流量は4気筒以下のエンジンの低回転、重負荷時の場合、吸入空気量の脈動振幅が大きく図10(a)に示す様に、逆流と呼ぶ負の空気流量を伴う正弦波に近い波形となる。 Generally the air flow rate is low rotation of the four-cylinder following engine, when the heavy load, as shown in large pulsation amplitude of the intake air quantity FIG. 10 (a), the near-sinusoidal with a negative air flow referred to as reverse flow a waveform. これは例えば、エンジン回転数が1000rpmの場合は、約33Hzの脈動周波数となる。 This example, when the engine speed is 1000 rpm, the pulsation frequency of about 33 Hz. このような現象は、エンジンの燃焼室形状、吸排気管形状およびエアクリーナ形状などによって異なった形態を示す。 This phenomenon shows a combustion chamber shape of the engine, the different forms depending on the breather shape and the air cleaner shape. 逆流検知の機能のない場合には、図10(b)に示す様に、真の空気流量が逆流であっても順流と判断してしまい、真の空気流量値に対して正の誤差を含んで出力する。 In the absence of function of the backflow detection, as shown in FIG. 10 (b), even true of the air flow rate back flow would be determined that the forward flow, includes a positive error with respect to the true air flow rate value in the output. 一方、逆流検知の機能をもつ第三、第四の実施例のような場合には、図10(c)のように逆流を判定することから、真の空気流量に近い流量信号を正確な流量信号を出力する。 On the other hand, the third, in the case such as the fourth embodiment, since determining the backflow as in FIG. 10 (c), the accurate flow flow signal close to the true air flow having the function of reverse flow detection and it outputs the signal.

【0030】図11は、本発明の実施例の効果を示したものである。 [0030] Figure 11 shows the effect of embodiments of the present invention. 真の空気流量(Q)に対する前記した支持体5の温度が25℃から80℃に上昇した場合の空気流量誤差(%)を示したものである。 It shows the air flow error (%) when the temperature of the support 5 described above with respect to the true air flow rate (Q) is increased to 80 ° C. from 25 ° C.. ここで、25℃の空気流量を基準としている。 Here, it is based on the air flow rate of 25 ° C.. 図中曲線(A)は従来例の特性であり、曲線(B)は本発明の実施例の特性である。 Figure curve (A) is a characteristic of the prior art, the curve (B) is a characteristic of the embodiment of the present invention. 本発明の実施例のように、第一のスリット16、第二のスリット15を、支持体5から発熱抵抗体2および温度補償用抵抗体3に至る熱抵抗をほぼ同じに設定することにより、 As in the embodiment of the present invention, the first slit 16, by a second slit 15, is set to be substantially the same thermal resistance extending from the support 5 to the heating resistor 2 and the temperature compensating resistor 3,
支持体5の温度の影響の少ない(流量測定誤差の少ない) Less affected by the temperature of the support 5 (small flow measurement error)
図中曲線Bのような特性が実現できる。 Characteristics as in the drawing the curve B can be realized.

【0031】本実施例では、基板1に形成された第一のスリット16は基板1の途中で途切れた構成になっているが、場合によっては、スリット16が基板1を完全に切断するような構成(発熱抵抗体2と温度補償用抵抗体3が完全に分離された構成)においても、組立行程がやや繁雑になるが、本発明の効果に変わりがないことは明確である。 [0031] In this embodiment, like the first slit 16 formed in the substrate 1 is has a configuration in which the data stream is divided during the substrate 1, in some cases, the slits 16 are completely cut the substrate 1 configuration also in (the heating resistor 2 and the configuration of the temperature compensating resistor 3 are completely separated), but the assembly process is somewhat complicated, that no change is to the effect of the present invention are clear. また、本実施例では、抵抗値補償用抵抗体4 Further, in the present embodiment, the resistance value compensation resistor 4
を常に有していたが、この抵抗体4がない場合においても本発明の効果に変わりがないことは明らかである。 Although was always have, it is clear that there is no change to the effect of the present invention even when there is no the resistor 4.

【0032】 [0032]

【発明の効果】本発明によれば、発熱抵抗体2および支持体5から温度補償用抵抗体3への熱絶縁がより効果的に行えると共に、第二のスリット15の形状を変えることにより支持体5から各抵抗体2,3に至る熱抵抗を同じにできることから、温度特性の優れた高精度の空気流量計測が可能な熱式空気流量計用測定素子及びそれを含む熱式空気流量計が提供できる。 According to the present invention, the support by changing the thermal insulation with performed more effectively to the heating resistor 2 and the support 5 temperature compensating resistor 3, the shape of the second slit 15 because it can heat resistance extending from the body 5 to the resistors 2 and 3 the same, the thermal type air flow meter including excellent measuring element and for it high accuracy of the air flow rate measurement can thermal air flow meter temperature characteristic There can be provided.

【図面の簡単な説明】 BRIEF DESCRIPTION OF THE DRAWINGS

【図1】本発明による第一の実施例の熱式空気流量計用測定素子を示す平面図である。 1 is a plan view showing a thermal type air flow meter for measuring element of the first preferred embodiment of the present invention.

【図2】図1の熱式空気流量計用測定素子を実装した実施例を示す断面図である。 2 is a sectional view showing an embodiment of mounting the thermal air flow meter for measuring element of FIG.

【図3】図1の発熱抵抗体の薄膜抵抗パターンを示す拡大図である。 3 is an enlarged view showing a thin-film resistor pattern of the heating resistor of FIG.

【図4】図1の温度補償抵抗体の薄膜抵抗パターンを示す拡大図である。 4 is an enlarged view showing a thin-film resistor pattern of the temperature compensating resistor in FIG.

【図5】本発明による第二の実施例の熱式空気流量計用測定素子を示す平面図である。 5 is a plan view showing a thermal type air flow meter for measuring element of the second embodiment according to the present invention.

【図6】本発明による第三の実施例の熱式空気流量計用測定素子を示す平面図である。 6 is a plan view showing a thermal type air flow meter for measuring element of the third embodiment according to the present invention.

【図7】本発明による第四の実施例の熱式空気流量計用測定素子を示す平面図である。 7 is a plan view showing a thermal type air flow meter for measuring element of a fourth embodiment according to the present invention.

【図8】図6の温度補償抵抗体の薄膜抵抗パターンを示す拡大図である。 8 is an enlarged view showing a thin-film resistor pattern of the temperature compensating resistor in FIG.

【図9】外部回路14と抵抗体2a、2b、3a、3b [9] the external circuit 14 and the resistor 2a, 2b, 3a, 3b
の電気回路を示す図である。 Is a diagram showing an electric circuit.

【図10】本発明の実施例の動作を示す図である。 Is a diagram illustrating the operation of the embodiment of the present invention; FIG.

【図11】本発明の実施例の効果を示す図である。 11 is a diagram showing the effect of embodiments of the present invention.

【図12】従来の熱式空気流量計用測定素子を示す鳥瞰図である。 12 is a bird's-eye view showing a conventional thermal air flow meter for measuring element.

【図13】従来の熱式空気流量計用測定素子を示す平面図である。 13 is a plan view showing the conventional thermal type air flow meter for measuring element.

【符号の説明】 DESCRIPTION OF SYMBOLS

1…基板、2,2a,2b…発熱抵抗体、3,3a,3 1 ... substrate, 2,2a, 2b ... the heating resistor, 3,3a, 3
b…温度補償用抵抗体 4…抵抗値補償用抵抗体、5…支持体、6…発熱体成膜部位、7…補償体成膜部位、8…空気流、9a,9b, b ... the temperature compensation resistor 4 ... resistance compensating resistor, 5 ... support, 6 ... heating element deposition site, 7 ... compensator film formation region, 8 ... air flow, 9a, 9b,
9c,9d,9e,9f…電極端子、10a,10b, 9c, 9d, 9e, 9f ... electrode terminal, 10a, 10b,
10c,10d,10e,10f…引出電極、11…基板支持部位、12…空気主通路、13…副通路、14… 10c, 10d, 10e, 10f ... lead electrodes, 11 ... substrate support portion, 12 ... air main passage, 13 ... sub-passage, 14 ...
外部回路、15…第二のスリット、16…第一のスリット、17a,17b…駆動回路、22a,22b,23 External circuit, 15 ... second slit, 16 ... first slit, 17a, 17b ... drive circuit, 22a, 22b, 23
…差動増幅器、21a,21b…トランジスタ ... differential amplifier, 21a, 21b ... transistor

───────────────────────────────────────────────────── フロントページの続き (72)発明者 渡辺 泉 茨城県ひたちなか市高場2477番地 株式会 社日立カーエンジニアリング内 (72)発明者 磯野 忠 茨城県ひたちなか市高場2477番地 株式会 社日立カーエンジニアリング内 ────────────────────────────────────────────────── ─── of the front page continued (72) inventor Watanabe, Izumi Hitachinaka City, Ibaraki Prefecture Takaba 2477 address stock company Hitachi car in engineering (72) inventor Hitachinaka City, Ibaraki Prefecture Tadashi Isono Takaba 2477 address stock company Hitachi car engineering the inner

Claims (4)

    【特許請求の範囲】 [The claims]
  1. 【請求項1】被測定流体の流れ方向に並設されている、 1. A are juxtaposed in the flow direction of the fluid to be measured,
    基板の発熱体成膜部位に成膜された発熱抵抗体および前記基板の補償体成膜部位に成膜された温度補償用抵抗体と、 前記発熱抵抗体及び前記温度補償用抵抗体から電気信号を取り出す為の、前記発熱体成膜部位及び前記補償体成膜部位を除いた前記基板の部位であって当該基板が支持される基板支持部位に成膜された複数の電極とから、前記被測定流体の流量を検出する検出回路として構成された熱式空気流量計用測定素子において、 前記発熱体成膜部位と前記補償体成膜部位とは、前記基板に形成された第一のスリットを挟んで、前記被測定流体の流れ方向に対して下流側と上流側に各々離間配置され、 且つ、前記温度補償用抵抗体と前記基板支持部位間に、 A temperature compensation resistor which is formed in the compensator film formation region of the heat generating resistor and the substrate that has been deposited on the heating element film formation region of the substrate, the electrical signal from the heating resistor and the temperature compensating resistor for extracting, from said heating element deposition site and a plurality of electrodes formed on the substrate supporting portion to which the substrate to a portion of the substrate except for the compensator film formation region is supported, the object the thermal type air flow meter for measuring element configured as a detection circuit for detecting the flow rate of the measurement fluid, the heating element film formation region and said compensator deposition site, a first slit formed in the substrate sandwiched therebetween, wherein are respectively spaced downstream and upstream of the flow direction of the fluid to be measured, and, between the substrate supporting portion and the temperature compensating resistor,
    前記基板支持部位端から前記温度補償用抵抗体への熱伝導を調整する為の第二のスリットを設けたことを特徴とする熱式空気流量計用測定素子。 The second thermal air flow meter for measuring element, characterized in that a slit for adjusting the heat conduction from the substrate support portion end to the temperature compensating resistor.
  2. 【請求項2】被測定流体の流れ方向に並設されている、 2. A are juxtaposed in the flow direction of the fluid to be measured,
    基板の発熱体成膜部位に成膜された一対の発熱抵抗体ならびに前記基板の補償体成膜部位に成膜された一対の温度補償用抵抗体と、 それぞれの前記発熱抵抗体及び前記温度補償用抵抗体から電気信号を取り出す為の、前記発熱体成膜部位及び前記補償体成膜部位を除いた前記基板の部位であって当該基板が支持される基板支持部位に成膜された複数の電極とから、前記被測定流体の流量を検出する検出回路として構成された熱式空気流量計用測定素子において、 前記発熱体成膜部位と前記補償体成膜部位とは、前記基板に形成された第一のスリットを挟んで、前記被測定流体の流れ方向に対して下流側と上流側に各々離間配置され、 且つ、前記発熱抵抗体と前記温度補償抵抗体とが前記流れ方向に対して重ならないように前記発熱体成膜部 A pair of temperature compensating resistor which is formed on a pair of compensator film formation region of the heat generating resistor and said substrate which is formed on the heating element film formation region of the substrate, each of said heating resistor and said temperature compensation from use resistors for taking out an electric signal, the heating element film formation region and a region of the substrate except for the compensator film formation region of the plurality of the substrates is formed on the substrate supporting portion to be supported from the electrodes, the at thermal type air flow meter for measuring element configured as a detection circuit for detecting the flow rate of the fluid to be measured, the heating element film formation region and said compensator film formation region is formed on the substrate first across the slit, wherein are respectively spaced downstream and upstream of the flow direction of the fluid to be measured, and the heat generating resistor and said temperature compensating resistor to the flow direction the heating element deposited portion so as not to overlap が前記補償体成膜部位に対して前記基板の先端方向に突き出て配置され、 且つ、前記温度補償用抵抗体と前記基板支持部位間に、 There is disposed projecting in the direction of the front end of the substrate relative to the compensating body film formation region, and, between the substrate supporting portion and the temperature compensating resistor,
    前記基板支持部位端から前記温度補償用抵抗体への熱伝導を調整する為の第二のスリットを設けたことを特徴とする熱式空気流量計用測定素子。 The second thermal air flow meter for measuring element, characterized in that a slit for adjusting the heat conduction from the substrate support portion end to the temperature compensating resistor.
  3. 【請求項3】請求項1または請求項2において、前記第二のスリットの形状は、前記基板を伝わる熱伝導における前記基板支持部位端から前記発熱抵抗体に至る熱抵抗と、前記基板支持部位端から前記温度補償用抵抗体に至る熱抵抗とがほぼ同じになるようにして定められたことを特徴とする熱式空気流量計用測定素子。 3. An apparatus according to claim 1 or claim 2, wherein the shape of the second slits has a thermal resistance extending from the substrate supporting portion end in the heat conduction transferred the substrate to the heat generating resistor, the substrate support portion thermal air flow meter for measuring element, characterized in that the thermal resistance extending from the edge to the temperature compensating resistor is determined so as to be approximately the same.
  4. 【請求項4】請求項1ないし請求項3のいずれか1項記載の熱式空気流量計用測定素子を含み被測定流体の流量を測定することを特徴とする熱式空気流量計。 4. The method of claim 1 to a thermal type air flow meter and measuring the flow rate according to any one of the thermal type air flow meter for fluid to be measured comprises a measuring device according to claim 3.
JP12018896A 1996-05-15 1996-05-15 Measuring element for thermal air flowmeter and thermal air flowmeter containing the same Pending JPH09304147A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP12018896A JPH09304147A (en) 1996-05-15 1996-05-15 Measuring element for thermal air flowmeter and thermal air flowmeter containing the same

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP12018896A JPH09304147A (en) 1996-05-15 1996-05-15 Measuring element for thermal air flowmeter and thermal air flowmeter containing the same

Publications (1)

Publication Number Publication Date
JPH09304147A true true JPH09304147A (en) 1997-11-28

Family

ID=14780096

Family Applications (1)

Application Number Title Priority Date Filing Date
JP12018896A Pending JPH09304147A (en) 1996-05-15 1996-05-15 Measuring element for thermal air flowmeter and thermal air flowmeter containing the same

Country Status (1)

Country Link
JP (1) JPH09304147A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6851311B2 (en) 2001-12-19 2005-02-08 Hitachi, Ltd. Thermal-type flow meter with bypass passage
JP2011220696A (en) * 2010-04-05 2011-11-04 Mitsubishi Electric Corp Thermal sensor element

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6851311B2 (en) 2001-12-19 2005-02-08 Hitachi, Ltd. Thermal-type flow meter with bypass passage
JP2011220696A (en) * 2010-04-05 2011-11-04 Mitsubishi Electric Corp Thermal sensor element

Similar Documents

Publication Publication Date Title
US4433576A (en) Mass airflow sensor
US4884443A (en) Control and detection circuitry for mass airflow sensors
US5548269A (en) Chip resistor and method of adjusting resistance of the same
EP1365216A1 (en) Flow sensor and method of manufacturing the same
US4821700A (en) Device for determining mass flow and direction of flow
US6557411B1 (en) Heating element type mass air flow sensor, and internal combustion engine-control apparatus using the sensor
US6357294B1 (en) Thermal air flow sensor
US4320655A (en) Quantity of flow meter
US4517837A (en) Air flow rate measuring apparatus
US6708560B2 (en) Measurement apparatus for measuring physical quantity such as fluid flow
US4283944A (en) Apparatus for measuring the mass of a fluid medium
US5635635A (en) Method and apparatus for detecting the intake air quantity of an engine
JP2008020193A (en) Thermal flow rate sensor
US5369994A (en) Flow sensor
US4843882A (en) Direct-heated flow measuring apparatus having improved sensitivity response speed
US4777820A (en) Apparatus for determining the flow rate of a flowing medium
US6470742B1 (en) Flow sensor
US4627279A (en) Direct-heated gas-flow measuring apparatus
US5717136A (en) Hot film type air flow quantity detecting apparatus applicable to vehicular internal combustion engine
US4831876A (en) Measurement probe
US6314807B1 (en) Thermal-type flow sensor
US4344322A (en) Device for air flow rate measurement in the air intake tube of an internal combustion engine
US5765432A (en) Flow sensor
US6988399B1 (en) Physical quantity detecting device having second lead conductors connected to the electrodes and extending to the circumference of the substrate
US6209402B1 (en) Measuring element, mass air flow meter therewith and compensating method for accurately measuring air flow