WO2018142931A1 - Thermal-type flow meter - Google Patents

Thermal-type flow meter Download PDF

Info

Publication number
WO2018142931A1
WO2018142931A1 PCT/JP2018/001138 JP2018001138W WO2018142931A1 WO 2018142931 A1 WO2018142931 A1 WO 2018142931A1 JP 2018001138 W JP2018001138 W JP 2018001138W WO 2018142931 A1 WO2018142931 A1 WO 2018142931A1
Authority
WO
WIPO (PCT)
Prior art keywords
recess
support member
passage
flow meter
sub
Prior art date
Application number
PCT/JP2018/001138
Other languages
French (fr)
Japanese (ja)
Inventor
征史 深谷
暁 上ノ段
忍 田代
斉藤　友明
直生 斎藤
Original Assignee
日立オートモティブシステムズ株式会社
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
Application filed by 日立オートモティブシステムズ株式会社 filed Critical 日立オートモティブシステムズ株式会社
Publication of WO2018142931A1 publication Critical patent/WO2018142931A1/en

Links

Images

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
    • G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
    • G01F1/68—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by using thermal effects
    • G01F1/684—Structural arrangements; Mounting of elements, e.g. in relation to fluid flow

Definitions

  • the present invention relates to a thermal flow meter.
  • FIG. 1 is a system diagram showing an electronic fuel injection type internal combustion engine control system.
  • the fuel supply amount and ignition timing which are the main control amounts of the internal combustion engine, are calculated using the output of the thermal flow meter as the main parameter. Therefore, improvement in measurement accuracy of thermal flow meters, suppression of changes over time, and improvement in reliability are important for improving vehicle control accuracy and ensuring reliability.
  • improvement in measurement accuracy of thermal flow meters, suppression of changes over time, and improvement in reliability are important for improving vehicle control accuracy and ensuring reliability.
  • Patent Document 1 a sensor in which a base portion 4 provided along a flow direction of a fluid flowing in a main passage and a heating resistor 3 for detecting a flow rate of the fluid flowing in the main passage are formed on a substrate.
  • a rectangular recess 5 is formed in the base portion 4, and the sensor element 2 has a detection portion surface in the recess 5, and an upper edge of the recess 5. It is fitted and fixed so as to be lower than 5a (see paragraph 0017 and FIG. 3).
  • the support 20 on which the sensing element 1 is mounted is formed of a laminated substrate made of glass ceramic.
  • the sensing element 1 is bonded to the support 20 with an epoxy or silicone-based adhesive 22, and the electrode 14 of the sensing element 1 and the electrode of the support 20 are electrically connected by a connection line such as a gold wire 23.
  • the support 20 on which the sensing element 1 is mounted is mounted on the housing case 24 with a silicone adhesive 23. Further, the housing case 24 is inserted into the main passage 25 (see paragraphs 0019, 0020 and FIG. 4).
  • Patent Document 1 water that could not be discharged at the discharge port of the sub-passage adheres to the sub-passage wall surface, and is conveyed to the base unit 4 wall surface along the sub-passage wall surface by the shearing force of the air flowing in the sub-passage. It is. Since the water enters the concave portion 5 of the base portion 4 and contacts any surface of the sensor element 2, a large measurement error occurs.
  • Patent Document 2 a part of the water that has flowed along the sub-passage wall surface flows through the gap between the support 20 on which the sensing element 1 is mounted and the housing case 24. For this reason, the water reaching the sensing element 1 is reduced and the occurrence of measurement errors is suppressed, but there is still room for further improvement.
  • an object of the present invention is to provide a thermal flow meter that sufficiently suppresses the water carried along the sub-passage wall surface from reaching the flow rate detection unit and suppresses measurement errors within an allowable range. is there.
  • the thermal flow meter of the present invention has an assembly plate including a flow rate detecting portion disposed in a recess provided in a part of the wall surface of the sub-passage, and the assembly plate surface is located upstream of the recess. While being arranged lower than the edge, a gap is provided between the assembly plate and the concave wall surface.
  • the water carried along the sub-passage wall surface is drawn into the separation vortex region of air generated near the upstream edge of the recess provided in a part of the sub-passage wall surface, and then the assembly plate And the air flow toward the gap between the recess and the wall of the recess is carried into the gap. Furthermore, this water is carried by the air flow in the gap, bypasses the back surface side of the flow rate detection unit of the assembly plate, and returns to the sub-passage wall surface on the downstream side of the flow rate detection unit. For this reason, it becomes difficult for water to reach the flow rate detector, and the occurrence of measurement errors is suppressed.
  • the front view which shows the external appearance of the thermal type flow meter which concerns on this invention.
  • the left view which shows the external appearance of the thermal type flow meter which concerns on this invention.
  • the rear view which shows the external appearance of the thermal type flow meter which concerns on this invention.
  • the right view which shows the external appearance of the thermal type flow meter which concerns on this invention.
  • the front view which shows the state of the housing which removed the front cover from the thermal type flow meter which concerns on this invention.
  • the rear view which shows the state of the housing which removed the back cover from the thermal type flow meter which concerns on this invention.
  • 2A is a cross-sectional view taken along line AA in FIG. 2C.
  • 3B is a schematic diagram of a BB cross section of FIG. 3A.
  • FIG. 3B is a schematic diagram of a BB cross section of FIG. 3A.
  • FIG. 3A is a schematic diagram showing a modification (Example 4) of FIG. Schematic diagram showing a modified example (Example 5) of FIG. 3A
  • FIG. 2 shows the appearance of the thermal flow meter 30.
  • 2A is a front view of the thermal flow meter 30,
  • FIG. 2B is a left side view,
  • FIG. 2C is a rear view, and
  • FIG. 2D is a right side view.
  • the thermal flow meter 30 includes a housing 302, a front cover 303, and a back cover 304.
  • the housing 302 has an external connection portion (connector portion) having a flange 312 for fixing the thermal flow meter 30 to the intake body constituting the main passage and an external terminal for electrical connection with an external device. 305 and a measurement unit 310 for measuring a flow rate and the like.
  • the measuring unit 310 is supported in a cantilever manner in the main passage by fixing the flange 312 to the intake body (intake pipe) 71.
  • the front cover 303 and the back cover 304 described above cover the housing in which the sub passage groove is formed, thereby forming a casing in which the sub passage is formed.
  • the sub-passage can also be configured with two members, a cover and a housing.
  • the measurement unit 310 provided in the main passage includes a flow rate detection unit 602 for measuring the flow rate of the measurement target gas IA flowing through the main passage and a temperature detection unit for measuring the temperature of the measurement target gas IA flowing through the main passage. 452 is provided.
  • the flow rate detection unit 602 is supported by a support member and provided in the sub passage.
  • Examples of the supporting member include a circuit package 400 and a printed board.
  • the temperature detection unit 452 for measuring the temperature of the measurement target gas IA is located at the center of the measurement unit 310 at a position where the upstream outer wall in the measurement unit 310 is recessed toward the downstream side, upstream from the upstream outer wall. It is provided with a shape that protrudes toward the surface.
  • the housing 302 is provided with auxiliary passage grooves 331 and 332 on both the front and back surfaces of the housing 302.
  • auxiliary passage grooves 331 and 332 are formed on both surfaces of the housing 302.
  • the sub-passage 330 shows an example having a first passage 31 and a second passage 32.
  • the first passage 31 is a passage formed from a main intake port 350 for taking in the measurement target gas IA flowing through the main passage 124 to a discharge port 355 for discharging a part of the taken in measurement gas IA.
  • the second passage 32 is a flow rate measurement passage formed toward the flow rate detection unit 602 from the sub intake port 34 for taking in the measurement target gas IA flowing in the first passage 31.
  • the back side sub-passage groove 334 includes a first passage wall 395, a back side sub-passage inner peripheral wall (second passage wall) 392, and a back side sub-passage that are formed to face each other.
  • An outer peripheral wall (second passage wall) 391 is formed.
  • the front end portions of the back side sub-passage inner peripheral wall 392 and the back side sub-passage outer peripheral wall 391 and the inner side surface of the back cover 304 are in close contact with each other, whereby the first passage 31 and the second passage of the housing 302 are in close contact with each other.
  • a sensor upstream side passage 32a of the passage 32 is formed.
  • a front side sub-passage inner peripheral wall (second passage wall) 393 and a front side sub-passage outer peripheral wall (second passage wall) 394 are provided on both sides of the front side sub-passage groove 332, and the sub-passage inner peripheral wall 393 and the sub-passage
  • the downstream side sub-passage of the housing 302 is formed by the close contact between the front end of the outer peripheral wall 394 in the height direction and the inner surface of the front cover 303.
  • Other gas to be measured IA flows in the flow path 387 formed by the measurement flow path back surface 431 and the back cover 304. Thereafter, the measured gas IA that has flowed through the flow path 387 moves toward the front side sub-passage groove 332 via the downstream portion 341 of the penetrating portion 382, and merges with the measured gas IA that flows through the flow path 386.
  • the gas to be measured IA that has joined flows through the front side sub-passage groove 332 and is discharged from the outlet 352 to the main passage.
  • the protrusion 356 forms a throttle, and the measurement gas IA is made into a laminar flow with little vortex. Further, the protrusion 356 increases the flow velocity of the measurement target gas IA. Thereby, measurement accuracy improves.
  • the protrusion 356 is formed on the front cover 303, which is a cover that faces the heat transfer surface exposed portion 436 of the flow rate detector 602 provided on the measurement flow path surface 430.
  • the circuit package 400 is fixed by being embedded in a fixing portion 372, 366, 373 of the housing 302 by a resin mold.
  • a fixing structure can be mounted on the thermal flow meter 30 by insert molding the circuit package 400 into the housing 302 simultaneously with resin molding of the housing 302.
  • the part where the flow rate detection unit 602 is arranged forms a secondary passage by being covered with a front cover 303 and a back cover 304.
  • a recess 750 is formed by increasing the thickness of a part of the back cover 304 that is the side wall surface of the sub-passage, and the flow rate detection unit 602 is provided in the recess 750.
  • a circuit package 400 is provided.
  • the support member that supports the flow rate detection element is provided in the recess provided on the side surface of the sub-passage.
  • the concave portion of the sub passage may be formed by the housing 302.
  • the flow detection element mounting surface side of the circuit package 400 is provided so as to face the front cover 303 side that is the wall surface facing the back cover 304 that is the sub-passage wall surface in which the recess 750 is formed.
  • a protrusion 356 is provided at a position facing the sub-passage wall surface where the recess 750 is formed. Most of the gas to be measured IA shown in FIG. 4 is a flow created by the surface of the measurement flow path surface 430 of the circuit package 400 and the projection 356 provided on the front cover 303 via the upstream portion 342 of the penetration portion 382. Flow along the road 386.
  • FIG. 5 is a schematic view of the BB cross section of FIG. 3A.
  • FIG. 5 shows a case where the IA is in a forward flow.
  • the measurement flow path surface 430 of the circuit package 400 is lower than the upstream edge 701 of the recess 750 (h1> 0). Therefore, the measurement target gas IA that flows along the surface 700 of the back cover 304 is separated at the upstream edge 701, and a separation vortex indicated by IB in the drawing is generated.
  • a part of the measurement target gas IA becomes a flow IC that bypasses the separation vortex, and is directed to the flow path 387 formed by the measurement flow path back surface 431 and the back cover 304.
  • FIG. 6 is a schematic view of the BB cross section of FIG. 3A similar to FIG.
  • the water droplet P on the surface 700 of the back cover 304 flows in the direction of the dotted arrow along the surface 700 due to the shear force of the flow of the measurement target gas IA. Since the generation region of the separation vortex IB in FIG. 5 has a lower pressure than the surroundings, the water droplet P reaches the upstream edge 701 of the recess 750 and is then drawn into this low pressure region. Furthermore, the water droplet P flows in the direction of the dotted arrow toward the flow path 387 by the shearing force of the flow IC that bypasses the water drop P and flows toward the flow path 387.
  • the water droplet P in the flow path 387 is carried by the measurement target gas IA and is discharged from the flow path 387 on the downstream side of the circuit package 400. As a result, the water droplet P does not reach the flow rate detection unit, and the occurrence of measurement errors is suppressed.
  • the sub passage has a protrusion and a recess at a position facing the protrusion, and the support member faces the side surface on which the protrusion is formed.
  • the support member faces the side surface on which the protrusion is formed.
  • FIG. 7 is a schematic view of the BB cross section of FIG. 3A similar to FIG.
  • the downstream edge 702 of the recess 750 is lower than the measurement flow path surface 430 of the circuit package 400 (h2> 0).
  • the measurement gas IA that flows along the measurement flow path surface 430 is blocked by the inner wall of the recess 750 below the downstream edge 702, and a part of the flow goes to the flow path 387. It becomes flow ID '.
  • this flow ID ′ is opposed to the flow IE ′ that is about to exit from the flow path 387, the flow IE ′ is weakened, and the flow IC is weakened accordingly, so that a shear force that directs the water droplet P toward the flow path 387 is generated. descend.
  • the downstream edge 702 of the recess 750 is lower than the measurement channel surface 430.
  • the measurement target gas IA that has flowed along the measurement flow path surface 430 is not blocked by the inner wall of the recess 750 below the downstream end edge 702, and becomes a straight flow ID.
  • the flow IE about to exit from the flow path 387 can easily flow out without facing the flow ID. Accordingly, the flow IC becomes stronger, and the shearing force that directs the water droplet P toward the flow path 387 increases. As a result, the water droplet P does not reach the flow rate detection unit, and the occurrence of measurement errors is suppressed.
  • Example 3 A third embodiment according to the present invention will be described with reference to FIG. Note that the description of the same configuration as that of the first embodiment is omitted.
  • FIG. 8 is a schematic view of the BB cross section of FIG. 3A similar to FIG.
  • the end of the circuit package 400 on the upstream side and the flow path 386 side has a tapered shape 401 that is inclined toward the detection element mounting surface side of the support member.
  • the taper shape 401 makes the measurement flow path surface 430 farther from the upstream edge 701 of the recess 750 and makes it difficult for the water droplets P to move to the measurement flow path surface 430 side.
  • the increase in the inlet area of the flow path 387 and the reduction of the pressure loss make it easier for the flow IC that bypasses the water droplet P and flows toward the flow path 387 to flow. For this reason, the shear force of the flow which directs the water droplet P to the flow path 387 becomes large. As a result, the water droplets P do not easily reach the flow rate detection unit, and the occurrence of measurement errors is suppressed.
  • Embodiment 4 according to the present invention will be described with reference to FIG. Note that the description of the same configuration as that of the first embodiment is omitted.
  • FIG. 9 is a schematic view of the BB cross section of FIG. 3A similar to FIG.
  • the end of the circuit package 400 on the flow path 387 side has a tapered shape 402 that is inclined toward the surface opposite to the detection element mounting surface of the support member.
  • the flow area IC of the flow path 387 is increased and the pressure loss is reduced, so that the flow IC that bypasses the water droplet P and flows toward the flow path 387 becomes easier to flow. For this reason, the shear force of the flow which directs the water droplet P to the flow path 387 becomes large. As a result, the water droplets P do not easily reach the flow rate detection unit, and the occurrence of measurement errors is suppressed.
  • FIG. 10 is a schematic view of the BB cross section of FIG. 3A similar to FIG.
  • the corner of the recess 750 has a tapered shape 703.
  • the pressure loss is further reduced as compared with the fourth embodiment, so that the flow IC that bypasses the water droplet P and flows toward the flow path 387 becomes easier to flow.
  • the shear force of the flow which directs the water droplet P to the flow path 387 becomes large.
  • the water droplets P do not easily reach the flow rate detection unit, and the occurrence of measurement errors is suppressed.

Abstract

A thermal-type flow meter, wherein water carried across a sub-passage wall surface is suppressed from reaching a flow rate detection part, and the occurrence of measurement error is suppressed. In this thermal-type flow meter, an assembly plate including the flow rate detection part is disposed in a recess provided in a portion of the sub-passage wall surface, an assembly plate surface is disposed lower than an upstream-side edge of the recess, and a gap is provided between the assembly plate and a recess wall surface. Water carried across the sub-passage wall surface is thereby drawn into an air separation vortex region that occurs near the upstream-side edge of the recess provided in a portion of the sub-passage wall surface, and the water is subsequently carried into the gap by an air flow toward the gap between the assembly plate and the recess wall surface. The water, carried by the air flow in the gap, then bypasses a back surface side of the flow rate detection part of the assembly plate and returns to the sub-passage wall surface downstream from the flow rate detection part. Water thereby does not readily reach the flow rate detection part, and the occurrence of measurement error is suppressed.

Description

熱式流量計Thermal flow meter
　本発明は熱式流量計に関する。 The present invention relates to a thermal flow meter.
　図１は、電子燃料噴射方式の内燃機関制御システムを示すシステム図である。 FIG. 1 is a system diagram showing an electronic fuel injection type internal combustion engine control system.
　内燃機関の主要な制御量である燃料供給量や点火時期はいずれも熱式流量計の出力を主パラメータとして演算される。従って熱式流量計の計測精度の向上や経時変化の抑制、信頼性の向上が、車両の制御精度の向上や信頼性の確保に関して重要である。特に近年、車両の省燃費に関する要望が非常に高く、また排気ガス浄化に関する要望が非常に高い。これらの要望に応えるには熱式流量計により計測される吸入空気である被計測気体ＩＡの流量の計測精度の向上が極めて重要である。 The fuel supply amount and ignition timing, which are the main control amounts of the internal combustion engine, are calculated using the output of the thermal flow meter as the main parameter. Therefore, improvement in measurement accuracy of thermal flow meters, suppression of changes over time, and improvement in reliability are important for improving vehicle control accuracy and ensuring reliability. In particular, in recent years, there has been a very high demand for fuel efficiency of vehicles and a very high demand for exhaust gas purification. In order to meet these demands, it is extremely important to improve the measurement accuracy of the flow rate of the measurement target gas IA that is the intake air measured by the thermal flow meter.
　内燃機関に導かれる吸入空気量を計測する熱式流量計として、例えば特許文献１や特許文献２に記載される技術がある。 As a thermal flow meter for measuring the amount of intake air guided to an internal combustion engine, for example, there are technologies described in Patent Document 1 and Patent Document 2.
　特許文献１では、主通路内を流れる流体の流れ方向に沿って設けられたベース部４と、前記主通路を流れる流体の流量を検知するための発熱抵抗体３が基板上に形成されたセンサ素子２とを備えた熱式流量センサ１Ａにおいて、前記ベース部４に矩形状の凹部５が形成されるとともに、該凹部５内に前記センサ素子２がその検知部表面が前記凹部５の上端縁５ａより低くなるように嵌め込まれて固着されている（段落００１７および図３参照）。 In Patent Document 1, a sensor in which a base portion 4 provided along a flow direction of a fluid flowing in a main passage and a heating resistor 3 for detecting a flow rate of the fluid flowing in the main passage are formed on a substrate. In the thermal flow sensor 1A including the element 2, a rectangular recess 5 is formed in the base portion 4, and the sensor element 2 has a detection portion surface in the recess 5, and an upper edge of the recess 5. It is fitted and fixed so as to be lower than 5a (see paragraph 0017 and FIG. 3).
　また、特許文献２では、センシング素子１を実装する支持体２０はガラスセラミック製積層基板により形成される。センシング素子１は支持体２０にエポキシまたはシリコーン系接着剤２２で接着され、センシング素子１の電極１４と支持体２０の電極は、例えば金線２３等の接続線により電気的に接続される。このセンシング素子１が実装された支持体２０はシリコーン系の接着剤２３によりハウジングケース２４に実装される。さらにハウジングケース２４は主通路２５に挿入される（段落００１９、段落００２０および図４参照）。 In Patent Document 2, the support 20 on which the sensing element 1 is mounted is formed of a laminated substrate made of glass ceramic. The sensing element 1 is bonded to the support 20 with an epoxy or silicone-based adhesive 22, and the electrode 14 of the sensing element 1 and the electrode of the support 20 are electrically connected by a connection line such as a gold wire 23. The support 20 on which the sensing element 1 is mounted is mounted on the housing case 24 with a silicone adhesive 23. Further, the housing case 24 is inserted into the main passage 25 (see paragraphs 0019, 0020 and FIG. 4).
特開２００８－２６１７２号公報JP 2008-26172 A 特開２００６－９８０５７号公報JP 2006-98057 A
　しかしながら、特許文献１では、副通路の排出口で排出しきれなかった水が副通路壁面に付着し、副通路内を流れる空気のせん断力で、副通路壁面を伝ってベース部４壁面まで運ばれる。その水は、ベース部４の凹部５内に進入し、センサ素子２のいずれかの面に接触するため、大きな計測誤差を生じてしまう。 However, in Patent Document 1, water that could not be discharged at the discharge port of the sub-passage adheres to the sub-passage wall surface, and is conveyed to the base unit 4 wall surface along the sub-passage wall surface by the shearing force of the air flowing in the sub-passage. It is. Since the water enters the concave portion 5 of the base portion 4 and contacts any surface of the sensor element 2, a large measurement error occurs.
　また、特許文献２では、副通路壁面を伝って流れてきた水の一部は、センシング素子１が実装された支持体２０とハウジングケース２４の間の隙間を流れる。このため、センシング素子１に到達する水が減り、計測誤差の発生が抑制されるが、更なる向上の余地が残されている。 Further, in Patent Document 2, a part of the water that has flowed along the sub-passage wall surface flows through the gap between the support 20 on which the sensing element 1 is mounted and the housing case 24. For this reason, the water reaching the sensing element 1 is reduced and the occurrence of measurement errors is suppressed, but there is still room for further improvement.
　このため、本発明の目的は、副通路壁面を伝って運ばれる水が流量検出部に到達することを十分に抑制し、計測誤差を許容範囲内に抑えた熱式流量計を提供することにある。 Therefore, an object of the present invention is to provide a thermal flow meter that sufficiently suppresses the water carried along the sub-passage wall surface from reaching the flow rate detection unit and suppresses measurement errors within an allowable range. is there.
　上記目的を達成するために、本発明の熱式流量計は、流量検出部を含む組付け板を副通路壁面の一部に設けた凹部内に配置し、組付け板面を凹部の上流側端縁より低く配置すると共に、組付け板と凹部壁面の間に隙間を設けている。 In order to achieve the above object, the thermal flow meter of the present invention has an assembly plate including a flow rate detecting portion disposed in a recess provided in a part of the wall surface of the sub-passage, and the assembly plate surface is located upstream of the recess. While being arranged lower than the edge, a gap is provided between the assembly plate and the concave wall surface.
　本発明によれば、副通路壁面を伝って運ばれる水は、副通路壁面の一部に設けた凹部の上流側端縁付近で発生する空気のはく離渦領域に引き込まれた後、組付け板と凹部壁面の間の隙間に向う空気流によって、この隙間内に運ばれる。さらにこの水は、隙間内の空気流に運ばれて組付け板の流量検出部裏面側を迂回し、流量検出部の下流側で副通路壁面に戻る。このため、水が流量検出部に到達しにくくなり、計測誤差の発生が抑制される。 According to the present invention, the water carried along the sub-passage wall surface is drawn into the separation vortex region of air generated near the upstream edge of the recess provided in a part of the sub-passage wall surface, and then the assembly plate And the air flow toward the gap between the recess and the wall of the recess is carried into the gap. Furthermore, this water is carried by the air flow in the gap, bypasses the back surface side of the flow rate detection unit of the assembly plate, and returns to the sub-passage wall surface on the downstream side of the flow rate detection unit. For this reason, it becomes difficult for water to reach the flow rate detector, and the occurrence of measurement errors is suppressed.
　上記した以外の課題、構成及び効果は、以下の実施形態の説明により明らかにされる。 Issues, configurations, and effects other than those described above will be clarified by the following description of the embodiments.
内燃機関制御システム図である。It is an internal combustion engine control system figure. 本発明に係る熱式流量計の外観を示す正面図。The front view which shows the external appearance of the thermal type flow meter which concerns on this invention. 本発明に係る熱式流量計の外観を示す左側面図。The left view which shows the external appearance of the thermal type flow meter which concerns on this invention. 本発明に係る熱式流量計の外観を示す背面図。The rear view which shows the external appearance of the thermal type flow meter which concerns on this invention. 本発明に係る熱式流量計の外観を示す右側面図。The right view which shows the external appearance of the thermal type flow meter which concerns on this invention. 本発明に係る熱式流量計から表カバーを取り外したハウジングの状態を示す正面図。The front view which shows the state of the housing which removed the front cover from the thermal type flow meter which concerns on this invention. 本発明に係る熱式流量計から裏カバーを取り外したハウジングの状態を示す背面図。The rear view which shows the state of the housing which removed the back cover from the thermal type flow meter which concerns on this invention. 図２ＣのＡ－Ａ断面図。2A is a cross-sectional view taken along line AA in FIG. 2C. 図３ＡのＢ－Ｂ断面の模式図。3B is a schematic diagram of a BB cross section of FIG. 3A. FIG. 図３ＡのＢ－Ｂ断面の模式図。3B is a schematic diagram of a BB cross section of FIG. 3A. FIG. 図３Ａの変形例（実施例２）を示した模式図。The schematic diagram which showed the modification (Example 2) of FIG. 3A. 図３Ａの変形例（実施例３）を示した模式図。The schematic diagram which showed the modification (Example 3) of FIG. 3A. 図３Ａの変形例（実施例４）を示した模式図FIG. 3A is a schematic diagram showing a modification (Example 4) of FIG. 図３Ａの変形例（実施例５）を示した模式図Schematic diagram showing a modified example (Example 5) of FIG. 3A
　以下、本発明の実施例を、図面を用いて詳述する。なお、本発明は、下記に記載する実施例に限定されるものではなく、特許請求の範囲に記載された本発明の精神を逸脱しない範囲で、種々の設計変更を行うことができるものである。例えば、前記した実施の形態は本発明を分かりやすく説明するために詳細に説明したものであり、必ずしも説明した全ての構成を備えるものに限定されるものではない。また、ある実施形態の構成の一部を他の実施形態の構成に置き換えることが可能であり、また、ある実施形態の構成に他の実施形態の構成を加えることも可能である。さらに、各実施形態の構成の一部について、他の構成の追加・削除・置換をすることが可能である。 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the embodiments described below, and various design changes can be made without departing from the spirit of the present invention described in the claims. . For example, the above-described embodiment has been described in detail for easy understanding of the present invention, and is not necessarily limited to one having all the configurations described. Further, a part of the configuration of an embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of an embodiment. Furthermore, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.
　[実施例１]
　以下、本発明の実施の形態を図に基づいて説明する。 [Example 1]
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
　図２は、熱式流量計３０の外観を示している。図２Ａは熱式流量計３０の正面図、図２Ｂは左側面図、図２Ｃは背面図、図２Ｄは右側面図である。 FIG. 2 shows the appearance of the thermal flow meter 30. 2A is a front view of the thermal flow meter 30, FIG. 2B is a left side view, FIG. 2C is a rear view, and FIG. 2D is a right side view.
　熱式流量計３０はハウジング３０２と表カバー３０３と裏カバー３０４とを備えている。ハウジング３０２は、熱式流量計３０を、主通路を構成する吸気ボディに固定するためのフランジ３１２と、外部機器との電気的な接続を行うための外部端子を有する外部接続部（コネクタ部）３０５と、流量等を計測するための計測部３１０を備えている。　熱式流量計３０は、フランジ３１２を吸気ボディ（吸気管）７１に固定することにより、計測部３１０が主通路内に片持ち状に支持される。 The thermal flow meter 30 includes a housing 302, a front cover 303, and a back cover 304. The housing 302 has an external connection portion (connector portion) having a flange 312 for fixing the thermal flow meter 30 to the intake body constituting the main passage and an external terminal for electrical connection with an external device. 305 and a measurement unit 310 for measuring a flow rate and the like. In the thermal flow meter 30, the measuring unit 310 is supported in a cantilever manner in the main passage by fixing the flange 312 to the intake body (intake pipe) 71.
　上述した表カバー３０３と裏カバー３０４が、副通路溝が形成されたハウジングを覆うことにより、副通路が形成されたケーシングとなる。本実施例では、３部材を用いる例を示したが、カバーとハウジングの２部材でも副通路は構成出来る。 The front cover 303 and the back cover 304 described above cover the housing in which the sub passage groove is formed, thereby forming a casing in which the sub passage is formed. In the present embodiment, an example in which three members are used has been described, but the sub-passage can also be configured with two members, a cover and a housing.
　主通路内に設けられる計測部３１０には、主通路を流れる被計測気体ＩＡの流量を計測するための流量検出部６０２や主通路を流れる被計測気体ＩＡの温度を計測するための温度検出部４５２が設けられている。 The measurement unit 310 provided in the main passage includes a flow rate detection unit 602 for measuring the flow rate of the measurement target gas IA flowing through the main passage and a temperature detection unit for measuring the temperature of the measurement target gas IA flowing through the main passage. 452 is provided.
　流量検出部６０２は、支持部材により支持されて、副通路内に設けられる。支持部材としては、回路パッケージ４００や、プリント基板が挙げられる。 The flow rate detection unit 602 is supported by a support member and provided in the sub passage. Examples of the supporting member include a circuit package 400 and a printed board.
　被計測気体ＩＡの温度を計測するための温度検出部４５２が、計測部３１０の中央部で、計測部３１０内の上流側外壁が下流側に向かって窪んだ位置に、上流側外壁から上流側に向かって突出する形状を成して設けられている。 The temperature detection unit 452 for measuring the temperature of the measurement target gas IA is located at the center of the measurement unit 310 at a position where the upstream outer wall in the measurement unit 310 is recessed toward the downstream side, upstream from the upstream outer wall. It is provided with a shape that protrudes toward the surface.
　次に、図３Ａおよび図３Ｂを用いて、ハウジング３０２内に構成される副通路及び回路パッケージの構成について説明する。 Next, with reference to FIG. 3A and FIG. 3B, the configuration of the sub-path and the circuit package configured in the housing 302 will be described.
　ハウジング３０２には、ハウジング３０２の表裏両面に副通路溝３３１，３３２が設けられている。表カバー３０３及び裏カバー３０４をハウジング３０２の表面及び裏面にかぶせることにより、ハウジング３０２の両面に連続した副通路３３０が形成される。 The housing 302 is provided with auxiliary passage grooves 331 and 332 on both the front and back surfaces of the housing 302. By covering the front cover 303 and the back cover 304 on the front surface and the back surface of the housing 302, continuous sub-passages 330 are formed on both surfaces of the housing 302.
　副通路３３０は、第１の通路３１と、第２の通路３２を有する例を示す。第１の通路３１は、主通路１２４を流れる被計測気体ＩＡを取り込む主取込口３５０から、取り込んだ被計測気体ＩＡの一部を排出する排出口３５５まで形成された通路である。第２の通路３２は、第１の通路３１に流れる被計測気体ＩＡを取り込む副取込口３４から、流量検出部６０２に向かって形成された流量計測用通路である。このように形成することで、ダストや水等を主に第１の通路３１に流し、きれいな空気を第２の通路にとりこむようにしている。 The sub-passage 330 shows an example having a first passage 31 and a second passage 32. The first passage 31 is a passage formed from a main intake port 350 for taking in the measurement target gas IA flowing through the main passage 124 to a discharge port 355 for discharging a part of the taken in measurement gas IA. The second passage 32 is a flow rate measurement passage formed toward the flow rate detection unit 602 from the sub intake port 34 for taking in the measurement target gas IA flowing in the first passage 31. By forming in this way, dust, water, etc. are mainly flowed into the 1st channel | path 31, and clean air is taken in into the 2nd channel | path.
　具体的には、図３Ｂに示すように、裏側副通路溝３３４は、対向して形成された第１通路用壁３９５と、裏側副通路内周壁（第２通路用壁）３９２と裏側副通路外周壁（第２通路用壁）３９１とにより形成されている。これら裏側副通路内周壁３９２と裏側副通路外周壁３９１とのそれぞれの高さ方向の先端部と裏カバー３０４の内側面とが密着することで、ハウジング３０２の第１の通路３１と第２の通路３２のセンサ上流側通路３２ａが成形される。 Specifically, as shown in FIG. 3B, the back side sub-passage groove 334 includes a first passage wall 395, a back side sub-passage inner peripheral wall (second passage wall) 392, and a back side sub-passage that are formed to face each other. An outer peripheral wall (second passage wall) 391 is formed. The front end portions of the back side sub-passage inner peripheral wall 392 and the back side sub-passage outer peripheral wall 391 and the inner side surface of the back cover 304 are in close contact with each other, whereby the first passage 31 and the second passage of the housing 302 are in close contact with each other. A sensor upstream side passage 32a of the passage 32 is formed.
　表側副通路溝３３２の両側には、表側副通路内周壁（第２通路用壁）３９３と表側副通路外周壁（第２通路用壁）３９４が設けられ、これら副通路内周壁３９３と副通路外周壁３９４の高さ方向の先端部と表カバー３０３の内側面とが密着することで、ハウジング３０２の下流側副通路が形成される。 A front side sub-passage inner peripheral wall (second passage wall) 393 and a front side sub-passage outer peripheral wall (second passage wall) 394 are provided on both sides of the front side sub-passage groove 332, and the sub-passage inner peripheral wall 393 and the sub-passage The downstream side sub-passage of the housing 302 is formed by the close contact between the front end of the outer peripheral wall 394 in the height direction and the inner surface of the front cover 303.
　他の被計測気体ＩＡは計測用流路裏面４３１と裏カバー３０４で作られる流路３８７の方を流れる。その後、流路３８７を流れた被計測気体ＩＡは、貫通部３８２の下流部３４１を介して表側副通路溝３３２の方に移り、流路３８６を流れている被計測気体ＩＡと合流する。合流した被計測気体ＩＡは、表側副通路溝３３２を流れ、出口３５２から主通路に排出される。 Other gas to be measured IA flows in the flow path 387 formed by the measurement flow path back surface 431 and the back cover 304. Thereafter, the measured gas IA that has flowed through the flow path 387 moves toward the front side sub-passage groove 332 via the downstream portion 341 of the penetrating portion 382, and merges with the measured gas IA that flows through the flow path 386. The gas to be measured IA that has joined flows through the front side sub-passage groove 332 and is discharged from the outlet 352 to the main passage.
　流路３８６では、突起部３５６は絞りを形成しており、被計測気体ＩＡを渦の少ない層流にする。また突起部３５６は被計測気体ＩＡの流速を高める。これにより、計測精度が向上する。突起部３５６は、計測用流路面４３０に設けた流量検出部６０２の熱伝達面露出部４３６に対向する方のカバーである表カバー３０３に形成されている。 In the flow path 386, the protrusion 356 forms a throttle, and the measurement gas IA is made into a laminar flow with little vortex. Further, the protrusion 356 increases the flow velocity of the measurement target gas IA. Thereby, measurement accuracy improves. The protrusion 356 is formed on the front cover 303, which is a cover that faces the heat transfer surface exposed portion 436 of the flow rate detector 602 provided on the measurement flow path surface 430.
　回路パッケージ４００はハウジング３０２の固定部３７２，３６６，３７３に樹脂モールドにより埋設して固定されている。このような固定構造は、ハウジング３０２の樹脂モールド成形と同時に、回路パッケージ４００をハウジング３０２にインサート成形することにより、熱式流量計３０に実装することができる。 The circuit package 400 is fixed by being embedded in a fixing portion 372, 366, 373 of the housing 302 by a resin mold. Such a fixing structure can be mounted on the thermal flow meter 30 by insert molding the circuit package 400 into the housing 302 simultaneously with resin molding of the housing 302.
　流量検出部６０２が配置される部分は、表カバー３０３と裏カバー３０４で蓋をされることにより副通路を形成している。 The part where the flow rate detection unit 602 is arranged forms a secondary passage by being covered with a front cover 303 and a back cover 304.
　図４に示すように、本実施例によれば、副通路の側壁面である裏カバー３０４の一部厚みを大きくすることで凹部７５０が形成されており、この凹部７５０に流量検出部６０２を備える回路パッケージ４００が設けられる。言い換えると、流量検出素子を支持する支持部材が副通路の側面に設けられた凹部に設けられている。なお、副通路の凹部は、ハウジング３０２で形成してもよい。 As shown in FIG. 4, according to the present embodiment, a recess 750 is formed by increasing the thickness of a part of the back cover 304 that is the side wall surface of the sub-passage, and the flow rate detection unit 602 is provided in the recess 750. A circuit package 400 is provided. In other words, the support member that supports the flow rate detection element is provided in the recess provided on the side surface of the sub-passage. The concave portion of the sub passage may be formed by the housing 302.
　回路パッケージ４００の流量検出素子搭載面側は、凹部７５０が形成される副通路壁面である裏カバー３０４とは対向する壁面である表側カバー３０３側を向くように設けられている。 The flow detection element mounting surface side of the circuit package 400 is provided so as to face the front cover 303 side that is the wall surface facing the back cover 304 that is the sub-passage wall surface in which the recess 750 is formed.
　凹部７５０が形成される副通路壁面とは対向する位置に突起部３５６が設けられている。
図４に示す被計測気体ＩＡはの多くは、貫通部３８２の上流部３４２を介して、回路パッケージ４００の計測用流路面４３０の表面と表カバー３０３に設けられた突起部３５６で作られる流路３８６の方を流れる。 A protrusion 356 is provided at a position facing the sub-passage wall surface where the recess 750 is formed.
Most of the gas to be measured IA shown in FIG. 4 is a flow created by the surface of the measurement flow path surface 430 of the circuit package 400 and the projection 356 provided on the front cover 303 via the upstream portion 342 of the penetration portion 382. Flow along the road 386.
　次に、本実施例による効果について説明する。副通路壁面を伝って運ばれる水が流量検出部に到達しにくくなり、計測誤差の発生が抑制される構成について説明する。 Next, the effect of this embodiment will be described. A description will be given of a configuration in which water carried along the sub-passage wall surface does not easily reach the flow rate detection unit, and generation of measurement errors is suppressed.
　図５は、図３ＡのＢ－Ｂ断面の概略図である。図５は、ＩＡが順流の場合を示す。回路パッケージ４００の計測用流路面４３０は、凹部７５０の上流側端縁７０１より低くなっている（ｈ１＞０）。このため、裏カバー３０４の表面７００に沿って流れた被計測気体ＩＡは上流側端縁７０１ではく離し、図にＩＢで示したはく離渦を生じる。被計測気体ＩＡの一部はこのはく離渦を迂回する流れＩＣとなり、計測用流路裏面４３１と裏カバー３０４で作られる流路３８７に向う。 FIG. 5 is a schematic view of the BB cross section of FIG. 3A. FIG. 5 shows a case where the IA is in a forward flow. The measurement flow path surface 430 of the circuit package 400 is lower than the upstream edge 701 of the recess 750 (h1> 0). Therefore, the measurement target gas IA that flows along the surface 700 of the back cover 304 is separated at the upstream edge 701, and a separation vortex indicated by IB in the drawing is generated. A part of the measurement target gas IA becomes a flow IC that bypasses the separation vortex, and is directed to the flow path 387 formed by the measurement flow path back surface 431 and the back cover 304.
　図６は、図５と同様な図３ＡのＢ－Ｂ断面の概略図である。裏カバー３０４の表面７００上の水滴Ｐは、被計測気体ＩＡの流れのせん断力により、表面７００に沿って点線矢印の方向に流れる。図５におけるはく離渦ＩＢの発生領域は周囲より低圧化しているため、水滴Ｐは凹部７５０の上流側端縁７０１に達した後、この低圧領域に引き込まれる。さらに、この水滴Ｐを迂回し流路３８７に向う流れＩＣのせん断力により、水滴Ｐは流路３８７に向って点線矢印の方向に流れる。流路３８７内の水滴Ｐは被計測気体ＩＡによって運ばれ、回路パッケージ４００の下流側で流路３８７から排出される。その結果、水滴Ｐは流量検出部に到達せず、計測誤差の発生が抑制される。 FIG. 6 is a schematic view of the BB cross section of FIG. 3A similar to FIG. The water droplet P on the surface 700 of the back cover 304 flows in the direction of the dotted arrow along the surface 700 due to the shear force of the flow of the measurement target gas IA. Since the generation region of the separation vortex IB in FIG. 5 has a lower pressure than the surroundings, the water droplet P reaches the upstream edge 701 of the recess 750 and is then drawn into this low pressure region. Furthermore, the water droplet P flows in the direction of the dotted arrow toward the flow path 387 by the shearing force of the flow IC that bypasses the water drop P and flows toward the flow path 387. The water droplet P in the flow path 387 is carried by the measurement target gas IA and is discharged from the flow path 387 on the downstream side of the circuit package 400. As a result, the water droplet P does not reach the flow rate detection unit, and the occurrence of measurement errors is suppressed.
　本実施例は、前記副通路は、突起部と、前記突起部と対向する位置に凹部を有しており、前記支持部材は、前記検出素子が、前記突起部が形成された側面と対向するように、前記凹部に配置され、前記支持部材と前記凹部には隙間があり、前記支持部材の計測素子側の面は、前記凹部の上流側端縁よりも凹部底面側に配置される構造をとる。そのようにすることで、水滴を支持部材裏面側に流しつつ、検出素子側への空気流れを確保できる。 In this embodiment, the sub passage has a protrusion and a recess at a position facing the protrusion, and the support member faces the side surface on which the protrusion is formed. As described above, there is a gap between the support member and the recess, and the measurement element side surface of the support member is disposed closer to the bottom surface of the recess than the upstream edge of the recess. Take. By doing so, it is possible to secure an air flow to the detection element side while flowing water droplets on the back surface side of the support member.
　なお、更なる好例として、図６に示したように、水滴Ｐが凹部７５０の上流側端縁７０１を回り込む際、その最大半径がｈ１であるとすると、この水滴Ｐが回路パッケージ４００の計測用流路面４３０側に乗り移らないようにするためには、上流端縁７０１下側の凹部７５０内壁と回路パッケージ４００の上流側端部の距離ｄとの間に、ｄ≧ｈ１の関係とするとよい。 As a further good example, as shown in FIG. 6, when the water droplet P wraps around the upstream edge 701 of the recess 750 and the maximum radius is h1, this water droplet P is used for measuring the circuit package 400. In order not to transfer to the flow path surface 430 side, a relationship of d ≧ h1 may be established between the inner wall of the recess 750 below the upstream edge 701 and the distance d between the upstream end of the circuit package 400. .
　［実施例２]
　図７を用いて、本発明に係る実施例２を説明する。実施例１と同様の構成については説明を省略する。 [Example 2]
Embodiment 2 according to the present invention will be described with reference to FIG. The description of the same configuration as in the first embodiment is omitted.
　図７は、図５と同様な図３ＡのＢ－Ｂ断面の概略図である。本実施例では、凹部７５０の下流端縁７０２は、回路パッケージ４００の計測用流路面４３０より低くなっている（ｈ２＞０）。図５に示した実施例１では、計測用流路面４３０に沿って流れた被計測気体ＩＡは下流端縁７０２下側の凹部７５０内壁に遮られ、その流れの一部は流路３８７に向う流れＩＤ’となる。この流れＩＤ’は流路３８７から出ようとする流れＩＥ’と対向するため、流れＩＥ’が弱まり、それに伴って流れＩＣが弱まることで、水滴Ｐを流路３８７に向わせるせん断力が低下する。 FIG. 7 is a schematic view of the BB cross section of FIG. 3A similar to FIG. In this embodiment, the downstream edge 702 of the recess 750 is lower than the measurement flow path surface 430 of the circuit package 400 (h2> 0). In Example 1 shown in FIG. 5, the measurement gas IA that flows along the measurement flow path surface 430 is blocked by the inner wall of the recess 750 below the downstream edge 702, and a part of the flow goes to the flow path 387. It becomes flow ID '. Since this flow ID ′ is opposed to the flow IE ′ that is about to exit from the flow path 387, the flow IE ′ is weakened, and the flow IC is weakened accordingly, so that a shear force that directs the water droplet P toward the flow path 387 is generated. descend.
　このため本実施例では、凹部７５０の下流側端縁７０２が、計測用流路面４３０より低くなっている。これにより、計測用流路面４３０に沿って流れた被計測気体ＩＡが下流端縁７０２より下側の凹部７５０内壁に遮られず、直進する流れＩＤとなる。これにより、流路３８７から出ようとする流れＩＥは流れＩＤと対向することなく、容易に流出できる。従って、流れＩＣが強まり、水滴Ｐを流路３８７に向わせるせん断力が増加する。その結果、水滴Ｐは流量検出部に到達せず、計測誤差の発生が抑制される。 For this reason, in this embodiment, the downstream edge 702 of the recess 750 is lower than the measurement channel surface 430. As a result, the measurement target gas IA that has flowed along the measurement flow path surface 430 is not blocked by the inner wall of the recess 750 below the downstream end edge 702, and becomes a straight flow ID. As a result, the flow IE about to exit from the flow path 387 can easily flow out without facing the flow ID. Accordingly, the flow IC becomes stronger, and the shearing force that directs the water droplet P toward the flow path 387 increases. As a result, the water droplet P does not reach the flow rate detection unit, and the occurrence of measurement errors is suppressed.
　［実施例３］
　図８を用いて、本発明に係る実施例３を説明する。なお、実施例１と同様の構成については説明を省略する。 [Example 3]
A third embodiment according to the present invention will be described with reference to FIG. Note that the description of the same configuration as that of the first embodiment is omitted.
　図８は、図６と同様な図３ＡのＢ－Ｂ断面の概略図である。回路パッケージ４００の上流側かつ流路３８６側の端部が、支持部材の検出素子搭載面側に傾斜するテーパ形状４０１となっている。このテーパ形状４０１により、計測用流路面４３０が凹部７５０の上流側端縁７０１からより遠くなり、水滴Ｐが計測用流路面４３０側に乗り移りにくくなる。また、流路３８７の入口面積の増加と圧力損失の低減により、水滴Ｐを迂回し流路３８７に向う流れＩＣがより流れ易くなる。このため、水滴Ｐを流路３８７に向わせる流れのせん断力が大きくなる。その結果、水滴Ｐは流量検出部に到達しにくくなり、計測誤差の発生が抑制される。 FIG. 8 is a schematic view of the BB cross section of FIG. 3A similar to FIG. The end of the circuit package 400 on the upstream side and the flow path 386 side has a tapered shape 401 that is inclined toward the detection element mounting surface side of the support member. The taper shape 401 makes the measurement flow path surface 430 farther from the upstream edge 701 of the recess 750 and makes it difficult for the water droplets P to move to the measurement flow path surface 430 side. In addition, the increase in the inlet area of the flow path 387 and the reduction of the pressure loss make it easier for the flow IC that bypasses the water droplet P and flows toward the flow path 387 to flow. For this reason, the shear force of the flow which directs the water droplet P to the flow path 387 becomes large. As a result, the water droplets P do not easily reach the flow rate detection unit, and the occurrence of measurement errors is suppressed.
　［実施例４］
　図９を用いて、本発明に係る実施例４を説明する。なお、実施例１と同様の構成については説明を省略する。 [Example 4]
Embodiment 4 according to the present invention will be described with reference to FIG. Note that the description of the same configuration as that of the first embodiment is omitted.
　図９は、図６と同様な図３ＡのＢ－Ｂ断面の概略図である。回路パッケージ４００の流路３８７側の端部が、支持部材の検出素子搭載面とは反対面側に傾斜するテーパ形状４０２となっている。 FIG. 9 is a schematic view of the BB cross section of FIG. 3A similar to FIG. The end of the circuit package 400 on the flow path 387 side has a tapered shape 402 that is inclined toward the surface opposite to the detection element mounting surface of the support member.
　このテーパ形状４０２を用いることで、流路３８７の流路面積の増加と圧力損失の低減により、水滴Ｐを迂回し流路３８７に向う流れＩＣがより流れ易くなる。このため、水滴Ｐを流路３８７に向わせる流れのせん断力が大きくなる。その結果、水滴Ｐは流量検出部に到達しにくくなり、計測誤差の発生が抑制される。 By using this taper shape 402, the flow area IC of the flow path 387 is increased and the pressure loss is reduced, so that the flow IC that bypasses the water droplet P and flows toward the flow path 387 becomes easier to flow. For this reason, the shear force of the flow which directs the water droplet P to the flow path 387 becomes large. As a result, the water droplets P do not easily reach the flow rate detection unit, and the occurrence of measurement errors is suppressed.
　［実施例５］
　図１０を用いて、本発明に係る実施例５を説明する。 [Example 5]
Embodiment 5 according to the present invention will be described with reference to FIG.
　図１０は、図９と同様な図３ＡのＢ－Ｂ断面の概略図である。実施例４の構成に加え、凹部７５０の角部がテーパ形状７０３となっている。これにより、実施例４よりもさらに圧力損失が低減されることで、水滴Ｐを迂回し流路３８７に向う流れＩＣがより一層流れ易くなる。このため、水滴Ｐを流路３８７に向わせる流れのせん断力が大きくなる。その結果、水滴Ｐは流量検出部に到達しにくくなり、計測誤差の発生が抑制される。 FIG. 10 is a schematic view of the BB cross section of FIG. 3A similar to FIG. In addition to the configuration of the fourth embodiment, the corner of the recess 750 has a tapered shape 703. As a result, the pressure loss is further reduced as compared with the fourth embodiment, so that the flow IC that bypasses the water droplet P and flows toward the flow path 387 becomes easier to flow. For this reason, the shear force of the flow which directs the water droplet P to the flow path 387 becomes large. As a result, the water droplets P do not easily reach the flow rate detection unit, and the occurrence of measurement errors is suppressed.
　３０…熱式流量計
　３１…第１の通路
　３２…第２の通路
　３４…副取込口
　３０２…ハウジング
　３０３…表カバー
　３０４…裏カバー
　３３０…副通路
　３５０…主取込口
　３５２…出口
　３５５…排出口
　３５６…突起部
　３８２…貫通部
　３８７…流路
　４００…回路パッケージ
　４３０…計測用流路面
　４３６…熱伝達面露出部
　６０２…流量検出部
　７５０…裏カバーの凹部 DESCRIPTION OF SYMBOLS 30 ... Thermal flow meter 31 ... 1st channel | path 32 ... 2nd channel | path 34 ... Sub intake port 302 ... Housing 303 ... Front cover 304 ... Back cover 330 ... Sub channel | path 350 ... Main intake port 352 ... Outlet 355 ... Exhaust port 356 ... Projection 382 ... Through part 387 ... Flow path 400 ... Circuit package 430 ... Measurement flow path surface 436 ... Heat transfer surface exposed part 602 ... Flow rate detection part 750 ... Concave part of back cover

Claims (8)

  1. 　主通路を流れる被計測気体の一部を取り込む副通路と、
    　支持部材に配置されることで前記副通路に計測面が曝される流量検出素子と、を備える熱式流量計において、
    　前記副通路は、突起部と、前記突起部と対向する位置に凹部を有しており、
    　前記支持部材は、前記検出素子が、前記突起部が形成された側面と対向するように、前記凹部に配置され、
    　前記支持部材と前記凹部には隙間があり、
    　前記支持部材の計測素子側の面は、前記凹部の上流側端縁よりも凹部底面側に配置される熱式流量計。     A sub-passage that takes in part of the gas to be measured flowing through the main passage;
    In a thermal flow meter comprising a flow rate detecting element that is disposed on a support member and a measurement surface is exposed to the auxiliary passage,
    The sub-passage has a protrusion and a recess at a position facing the protrusion,
    The support member is disposed in the recess so that the detection element faces the side surface on which the protrusion is formed.
    There is a gap between the support member and the recess,
    The surface on the measurement element side of the support member is a thermal flow meter that is disposed closer to the bottom surface of the recess than the upstream edge of the recess.
  2. 　前記凹部の上流側端縁と前記支持部材の前記流量検出素子搭載面の高さの差ｈ１と、前記凹部の上流側内壁と前記支持部材の上流側端部の距離ｄが、ｄ≧ｈ１の関係にある請求項１に記載の熱式流量計。 The height difference h1 between the upstream edge of the recess and the flow detection element mounting surface of the support member, and the distance d between the upstream inner wall of the recess and the upstream end of the support member satisfy d ≧ h1. The thermal type flow meter according to claim 1 which is in a relation.
  3. 　前記凹部の下流側端縁は、前記支持部材の検出素子側の面よりも凹部底面側に配置した請求項１に記載の熱式流量計。 The thermal flow meter according to claim 1, wherein the downstream end edge of the recess is disposed closer to the bottom surface of the recess than the surface on the detection element side of the support member.
  4. 　前記支持部材は、上流側端部に、前記検出素子搭載面側に傾斜するテーパ形状を備える請求項１に記載の熱式流量計。 The thermal flow meter according to claim 1, wherein the support member has a tapered shape inclined toward the detection element mounting surface side at an upstream end portion.
  5. 　前記支持部材は、上流側端部に、前記検出素子搭載面とは反対面側に傾斜するテーパ形状を備える請求項１に記載の熱式流量計。 The thermal type flow meter according to claim 1, wherein the support member has a tapered shape at an upstream end portion that is inclined toward a surface opposite to the detection element mounting surface.
  6. 　前記凹部の角部は、前記支持部材に形成されたテーパ形状と対応するテーパ形状を備える請求項４に記載の熱式流量計。 The thermal flow meter according to claim 4, wherein a corner portion of the concave portion has a tapered shape corresponding to a tapered shape formed on the support member.
  7. 　前記支持部材は、前記流量検出素子の計測面が露出するように樹脂で封止するチップパッケージである請求項１乃至６の何れかに記載の熱式流量計。 The thermal flow meter according to any one of claims 1 to 6, wherein the support member is a chip package sealed with a resin so that a measurement surface of the flow rate detection element is exposed.
  8. 　前記支持部材は、前記流量検出素子を収容する凹部を有するプリント基板である請求項１乃至６の何れかに記載の熱式流量計。 The thermal flow meter according to any one of claims 1 to 6, wherein the support member is a printed circuit board having a concave portion for accommodating the flow rate detection element.
PCT/JP2018/001138 2017-01-31 2018-01-17 Thermal-type flow meter WO2018142931A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2017014968A JP6674917B2 (en) 2017-01-31 2017-01-31 Thermal flow meter
JP2017-014968 2017-01-31

Publications (1)

Publication Number Publication Date
WO2018142931A1 true WO2018142931A1 (en) 2018-08-09

Family

ID=63040466

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2018/001138 WO2018142931A1 (en) 2017-01-31 2018-01-17 Thermal-type flow meter

Country Status (2)

Country Link
JP (1) JP6674917B2 (en)
WO (1) WO2018142931A1 (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP7056590B2 (en) 2019-01-15 2022-04-19 株式会社デンソー Air flow measuring device

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008058131A (en) * 2006-08-31 2008-03-13 Hitachi Ltd Thermal type gas flowmeter

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2008058131A (en) * 2006-08-31 2008-03-13 Hitachi Ltd Thermal type gas flowmeter

Also Published As

Publication number Publication date
JP2018124099A (en) 2018-08-09
JP6674917B2 (en) 2020-04-01

Similar Documents

Publication Publication Date Title
US7891240B2 (en) Thermal type flow measuring device
JP5496027B2 (en) Thermal air flow meter
JP6965358B2 (en) Thermal flow meter
JP5279667B2 (en) Thermal air flow sensor
JP5758850B2 (en) Thermal flow meter
JP4929335B2 (en) Thermal flow meter
JP5755185B2 (en) Thermal flow meter
JP6771111B2 (en) Physical quantity detector
JP2015021953A (en) Thermal air flowmeter
WO2013187231A1 (en) Thermal flow meter
JP5801761B2 (en) Thermal flow meter
JP2014001931A (en) Thermal flowmeter
WO2018142931A1 (en) Thermal-type flow meter
JP5455848B2 (en) Thermal flow sensor
WO2020202722A1 (en) Physical-quantity detection device
JP6855590B2 (en) Physical quantity detector
CN109791064B (en) Air flow measuring device
JP5711399B2 (en) Thermal air flow meter
JPWO2019064933A1 (en) Physical quantity detector
CN113167620B (en) Physical quantity measuring device
JP2020034508A (en) Physical amount detection device
KR20160016690A (en) Sensor for determining at least one parameter of a fluid medium flowing through a measuring channel
JP4512616B2 (en) Air flow measurement module

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 18748226

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 18748226

Country of ref document: EP

Kind code of ref document: A1