WO2010150302A1 - Pressure sensor and method for manufacturing the same - Google Patents

Pressure sensor and method for manufacturing the same Download PDF

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Publication number
WO2010150302A1
WO2010150302A1 PCT/JP2009/002829 JP2009002829W WO2010150302A1 WO 2010150302 A1 WO2010150302 A1 WO 2010150302A1 JP 2009002829 W JP2009002829 W JP 2009002829W WO 2010150302 A1 WO2010150302 A1 WO 2010150302A1
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Prior art keywords
pressure sensor
pressure
hole
permeation
gas
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PCT/JP2009/002829
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French (fr)
Japanese (ja)
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宮本泰介
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トヨタ自動車株式会社
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Priority to PCT/JP2009/002829 priority Critical patent/WO2010150302A1/en
Publication of WO2010150302A1 publication Critical patent/WO2010150302A1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L19/00—Details of, or accessories for, apparatus for measuring steady or quasi-steady pressure of a fluent medium insofar as such details or accessories are not special to particular types of pressure gauges
    • G01L19/06—Means for preventing overload or deleterious influence of the measured medium on the measuring device or vice versa
    • G01L19/0627—Protection against aggressive medium in general

Definitions

  • the present invention relates to a pressure sensor that detects the pressure of a gas.
  • Patent Document 1 As a pressure sensor for detecting the pressure of a high-pressure gas, for example, there is a pressure sensor disclosed in Patent Document 1.
  • the pressure sensor described in Patent Document 1 has a structure in which a deep hole is formed in a metal member made of a low thermal expansion metal such as an Fe—Ni system or an Fe—Ni—Co system.
  • the pressure of the gas is measured by introducing a high-pressure gas to be measured into the above-described hole and detecting the deformation of the bottom of the hole with a strain gauge.
  • the pressure sensor described in Patent Document 1 uses a metal member having such a structure to increase the pressure resistance against high-pressure gas.
  • the material of the metal member is required to have a low expansion coefficient and high strength.
  • the material of the metal member is required to have hydrogen embrittlement resistance. For this reason, it is very difficult to review the material of the metal member itself.
  • the problem to be solved by the present invention is to accurately detect the pressure of a gas that may permeate through a metal member in a pressure sensor including a metal member having a deep hole. It is to provide a technology that can.
  • the pressure sensor which is one aspect of the present invention is configured as follows.
  • a pressure sensor which is one embodiment of the present invention is a pressure sensor used to detect the pressure of a gas, which is a hole into which the gas is introduced, and is a hole having one end opened and the other end having a bottom.
  • a permeation suppression film that suppresses the permeation of gas is formed at the bottom of the hole provided in the metal member. Therefore, it is possible to suppress the gas that may permeate through the metal member from permeating through the metal member from the inside of the hole toward the pressure detection unit. As a result, the pressure detection unit is prevented from erroneously detecting the pressure by the permeated gas, so that the gas pressure can be detected with high accuracy.
  • the pressure detection film is formed at least on the bottom of the hole. That's fine.
  • the permeation suppression film may be formed by spraying a material of the permeation suppression film on the bottom. If it is such an aspect, since a permeation
  • the permeation suppression film may be formed by heating and brazing a brazing material including the material of the permeation suppression film to the bottom. If it is such an aspect, since a permeation
  • the permeation suppression film may include aluminum. If it is such an aspect, it can suppress that hydrogen gas permeate
  • the pressure detection unit may be bonded to the outer surface of the metal member with glass. If it is such an aspect, it can suppress that gas permeate
  • the present invention can also be configured as a pressure sensor manufacturing method, a fuel cell system including the pressure sensor, and a vehicle including the fuel cell system. is there.
  • FIG. 1 is a diagram illustrating a schematic configuration of a fuel cell system 100 including a pressure sensor 10.
  • FIG. 2 is a cross-sectional view showing a schematic configuration of a pressure sensor 10.
  • FIG. 3 is an enlarged cross-sectional view of a metal stem 20.
  • FIG. 2 is a flowchart showing a first embodiment of a manufacturing method of the pressure sensor 10; It is a figure which shows the formation method of the permeation
  • FIG. 1 is a diagram showing a schematic configuration of a fuel cell system 100 including a pressure sensor 10 as an embodiment of the present invention.
  • the fuel cell system 100 includes two hydrogen tanks 110 and 120.
  • the hydrogen tanks 110 and 120 are connected to the hydrogen tanks 110 and 120 through the branch pipes 130 for filling the hydrogen tanks 110 and 120 with hydrogen gas.
  • the hydrogen tanks 110 and 120 are filled with, for example, 70 MPa hydrogen gas through the filling port 135.
  • the hydrogen tanks 110 and 120 are connected to the fuel cell 160 through the collecting pipe 140 and the pressure regulating valve 150.
  • the fuel cell 160 generates power by receiving supply of hydrogen gas from the hydrogen tanks 110 and 120 and introducing air by a blower or the like (not shown).
  • the fuel cell system 100 is mounted on an electric vehicle and used as a power source, for example.
  • the pressure sensor 10 for detecting the pressure of the hydrogen gas supplied from the hydrogen tanks 110 and 120 is attached to the collecting pipe 140.
  • the output of the pressure sensor 10 is input to an ECU (Electronic Control Unit) 170.
  • ECU 170 estimates the remaining amount of hydrogen gas in hydrogen tanks 110 and 120 according to the pressure of hydrogen gas detected by pressure sensor 10. Although two hydrogen tanks are shown in FIG. 1, the number is not particularly limited.
  • FIG. 2 is a cross-sectional view showing a schematic configuration of the pressure sensor 10.
  • the pressure sensor 10 includes a metal stem 20, a housing 30, a screw member 40, a connector terminal 50, a connector case 80, and the like.
  • FIG. 2 shows the pressure sensor 10 so that the connector case 80 is positioned upward and the housing 30 is positioned downward, there is no particular directionality when the pressure sensor 10 is used.
  • FIG. 3 is an enlarged cross-sectional view of the metal stem 20.
  • the metal stem 20 is a substantially cylindrical member having a hole 21 having a lower end opened and a bottom at the upper end. As will be described later, hydrogen gas to be detected in pressure is introduced into the hole 21.
  • the inner diameter of the hole 21 is about 2.0 to 3.0 mm, and its bottom is formed in a thin shape of 0.5 to 1.0 mm.
  • the thin-walled bottom portion is referred to as a diaphragm 22.
  • the lower end side of the metal stem 20 has an outer diameter larger than that of the upper end side, and a step portion 23 is formed therebetween.
  • the thickness of the side wall at the upper end of the metal stem 20 is 4.0 to 5.0 mm.
  • a sensor substrate 24 is bonded to the upper surface of the diaphragm 22 by a glass 25.
  • a glass 25 for example, hard glass or low-melting glass such as lead glass can be used.
  • a strain gauge 26 as a pressure detection unit and an amplifier circuit (not shown) for amplifying the output of the strain gauge 26 are mounted on the sensor substrate 24.
  • the upper surface of the sensor substrate 24 is covered with a silicon gel 27 in order to protect a bonding wire (not shown) that outputs an electrical signal from the sensor substrate 24.
  • a permeation suppression film 28 containing aluminum is formed on the bottom surface of the hole portion 21 in order to suppress hydrogen gas introduced into the hole portion 21 from passing through the diaphragm 22.
  • the thickness of the permeation suppression film 28 is 0.01 to 0.1 mm. A method of forming the permeation suppression film 28 on the bottom surface of the hole 21 will be described later.
  • the metal stem 20 needs to have high strength because high-pressure hydrogen gas is introduced into the hole 21. Moreover, since the glass 25 is softened and the sensor substrate 24 is bonded, it is required that the coefficient of thermal expansion is low. Therefore, the metal stem 20 can be formed of, for example, a low thermal expansion metal such as an Fe—Ni alloy or an Fe—Ni—Co alloy.
  • the housing 30 (see FIG. 2) is a substantially cylindrical member that is directly attached to the collecting pipe 140 shown in FIG. 1, and a screw portion 31 used for attachment to the collecting pipe 140 is provided on the outer periphery below the housing 30. Is formed.
  • the interior of the housing 30 has a structure in which the inner diameter is reduced in three stages from the upper side to the lower side.
  • the portion with the largest inner diameter is referred to as a circuit storage portion 32
  • the middle portion with the second largest inner diameter is referred to as a stem storage portion 33.
  • the lower part having the smallest inner diameter is referred to as a gas introduction channel 34.
  • a thread 35 for attaching the screw member 40 is formed on the inner surface of the stem storage portion 33.
  • the housing 30 can be formed by, for example, carbon steel (for example, S15C) having both corrosion resistance and high strength, which is galvanized to increase corrosion resistance, or XM7, SUS430, SUS304, and SUS630 that have corrosion resistance.
  • the screw member 40 is a substantially cylindrical member that covers the outer periphery of the metal stem 20.
  • the screw member 40 is made of, for example, carbon steel.
  • a screw thread 41 used for attachment to the stem storage portion 33 is formed on the outer periphery below the screw member 40.
  • a cylindrical portion provided in the center of the screw member 40 is formed with a step portion 42 that contacts the step portion 23 of the metal stem 20.
  • the upper part of the screw member 40 is formed in a bowl shape.
  • a ceramic substrate 60 is bonded to the bottom surface of the bowl-shaped portion.
  • the ceramic substrate 60 is electrically connected to the sensor substrate 24 bonded to the upper surface of the metal stem 20 by bonding wires 61.
  • an IC chip 62 for performing predetermined signal processing on a signal input from the sensor substrate 24 is mounted on the ceramic substrate 60.
  • the ceramic substrate 60 is provided with pins 63 that are electrically connected to the IC chip 62.
  • the connector terminal 70 is a member formed by insert molding the metal terminal 72 into resin.
  • the connector terminal 70 is fitted into the upper part of the hook-shaped portion of the screw member 40.
  • the metal terminal 72 is joined to a pin 63 provided on the ceramic substrate 60 by laser welding or the like. Although only one metal terminal 72 is shown in FIG. 2, a terminal used for power supply to the sensor substrate 24 and the ceramic substrate 60, a terminal used for signal output, a terminal used for grounding, etc. A plurality of lines are provided.
  • the connector case 80 is a member surrounding the periphery of the metal terminal 72.
  • the connector case 80 is inserted into the opening at the upper end of the housing 30 via the O-ring 90. At this time, the upper end of the housing 30 is caulked inward, and the connector case 80 is integrally fixed to the upper portion of the housing 30.
  • high-pressure hydrogen of a maximum of 70 MPa is introduced from the hydrogen tanks 110 and 120 into the hole 21 of the metal stem 20 through the gas introduction channel 34 provided in the housing 30. .
  • the diaphragm 22 is deformed by the pressure of the hydrogen gas.
  • the strain gauge 26 mounted on the sensor substrate 24 bonded to the upper surface of the diaphragm 22 is also deformed.
  • an electrical signal corresponding to the degree of deformation is output from the strain gauge 26, and the electrical signal is transmitted to the ECU 170 through the sensor substrate 24, the ceramic substrate 60, and the metal terminal 72.
  • the ECU 170 detects the pressure of the hydrogen gas supplied from the hydrogen tanks 110 and 120 in accordance with this electrical signal.
  • FIG. 4 is a flowchart showing a first embodiment of a manufacturing method of the pressure sensor 10.
  • a metal stem 20 having a hole 21 is prepared (step S10), and a permeation suppression film 28 containing aluminum is formed on the bottom surface of the hole 21 by thermal spraying (Ste S20).
  • FIG. 5 is a diagram showing a method of forming the permeation suppression film 28 in the first embodiment.
  • a permeation suppression film 28 having a thickness of 0.01 to 0.1 mm is formed on the bottom surface of the hole 21 of the metal stem 20 by using a thermal spraying apparatus 200.
  • the reason for limiting the thickness in this way is that if it is thinner than 0.01 mm, the permeation suppression film 28 may be broken by the introduction of high-pressure hydrogen. If it is thicker than 0.1 mm, the strain gauge 26 This is because there is a possibility of affecting the sensitivity.
  • membrane for example, film
  • the permeation suppression film 28 As a material for the permeation suppression film 28, aluminum, aluminum alloy, austenitic stainless steel, ceramic, or the like can be used. Since aluminum and aluminum alloys have the property of not chemically adsorbing hydrogen molecules, the permeation of hydrogen gas can be suppressed. In addition, austenitic stainless steel such as SUS316L absorbs hydrogen, but has a property that diffusion of hydrogen into the inside thereof is extremely slow, so that hydrogen gas permeation can be substantially suppressed. Become. In addition, ceramic films such as carbides, oxides, and nitrides do not have the property of adsorbing or dissociating hydrogen molecules, nor the property of diffusing atomic hydrogen like metal. Therefore, the permeation of hydrogen gas can also be suppressed by forming a ceramic film.
  • thermal spraying method for example, flame spraying, HVOF (High-Velocity-Oxygen-Fuel) spraying, plasma spraying, or the like can be applied.
  • HVOF spraying that can be sprayed on is suitable.
  • plasma spraying that can be sprayed at a high temperature of several tens of thousands of degrees.
  • Step S30 when the permeation suppression film 28 is formed on the bottom surface of the hole portion 21 of the metal stem 20 by thermal spraying, the sensor substrate 24 on which the strain gauge 26 is mounted is subsequently adhered to the upper surface of the diaphragm 22 by the glass 25.
  • Step S40 the metal stem 20 is attached to the housing 30 by the screw member 40, and the connector terminal 70 and the connector case 80 are attached to the housing 30 to assemble the pressure sensor 10 (step S40).
  • the diaphragm 22 portion in the metal stem 20 is the thinnest portion in the metal stem 20, so that hydrogen is most easily permeable.
  • the permeation suppression film 28 is formed on the bottom surface of the hole 21 of the metal stem 20, that is, on the inner surface of the diaphragm 22. For this reason, even if high-pressure hydrogen gas is introduced into the hole 21, the hydrogen is suppressed from permeating through the diaphragm 22. As a result, the hydrogen is suppressed from staying in the glass 25 or the like existing between the metal stem 20 and the strain gauge 26, so that the output of the strain gauge 26 is stabilized and the pressure of the hydrogen gas is accurately detected. It becomes possible.
  • the permeation suppression film 28 is formed only on the bottom portion of the hole portion 21 corresponding to the lower surface of the diaphragm 22. This is because even if hydrogen permeates from other parts (for example, the side wall of the hole 21), the influence of the strain gauge 26 on the detection of the deformation of the diaphragm 22 is negligible. As described above, in this embodiment, since it is not necessary to form the permeation suppression film 28 in the whole hole portion 21, the permeation suppression film 28 can be efficiently formed by a thermal spraying method.
  • the permeation suppression film 28 having high adhesion can be formed in an air atmosphere in a short time, so that the manufacturing cost can be reduced. Furthermore, according to the present embodiment, since the permeation of hydrogen can be suppressed by forming the permeation suppressing film 28, the pressure detection accuracy can be improved without changing the material of the metal member 20. .
  • the permeation suppression film 28 is formed on the bottom of the hole 21 of the metal stem 20 by thermal spraying. In contrast, in the second embodiment, the permeation suppression film 28 is formed using a brazing technique.
  • FIG. 6 is a flowchart showing a second embodiment of the manufacturing method of the pressure sensor 10.
  • the manufacturing method of this embodiment is different from the manufacturing method of the first embodiment shown in FIG. 4 only in the method of forming the permeation suppression film 28 in step S20b. Therefore, the description of steps (steps S10, S30, S40) other than step S20b is omitted.
  • FIG. 7 is a diagram showing a method of forming the permeation suppression film 28 in this example.
  • the opening of the hole 21 of the metal stem 20 is directed upward, and the inner surface of the hole 21 is cleaned. Specifically, after removing dirt, the oxide film is removed by pickling or the like. Then, aluminum brazing is set as a brazing material in the cleaned hole 21 and heated in an oxygen-free atmosphere. Then, the brazing material is melted and diffused to the bottom surface of the hole portion 21 to form a permeation suppression film 28.
  • brazing material aluminum brazing, gold brazing, silver brazing, solder, etc. can be used. If gold brazing is used, it is possible to form the permeation suppression film 28 having a long-term stable property. In addition, since silver solder has good wettability, it can be diffused well on the bottom surface of the hole 21.
  • silver solder for example, an Ag—Cu—Sn silver solder, an Ag—Cu—Zn—Cd silver solder, an Ag—Cu—Zn—Sn silver solder can be used.
  • Ag-Cu-Sn-based silver brazing is suitable for brazing in a furnace because of its low vapor pressure and easy evaporation.
  • Ag-Cu-Zn-Cd and Ag-Cu-Zn-Sn-based silver brazing are suitable for torch brazing because of their high vapor pressure and difficulty in evaporation. If a Pb—Sn or Sn—Ag solder is used as the brazing material, the permeation suppression film 28 can be easily formed because the melting point is low.
  • the pressure sensor 10 can be manufactured at low cost by forming the permeation suppression film 28 using the brazing material containing these metals.
  • the melting point of gold brazing is about 950 ° C.
  • silver brazing is 650 to 800 ° C.
  • aluminum brazing is about 600 ° C.
  • solder is 190 to 250 ° C. Therefore, if a brazing material is used as the material of the permeation suppression film 28, the most convenient brazing material can be selected on the production line of the pressure sensor 10.
  • the pressure sensor 10 is attached to the collecting pipe 140 of the fuel cell system 100, but may be directly attached to the hydrogen tanks 110 and 120. Further, it may be attached to piping downstream of the pressure regulating valve 150. Further, the pressure sensor 10 is not only used for measuring the pressure of hydrogen, but may be used for measuring the pressure of a gas (for example, helium) that may permeate the metal stem 20.
  • a gas for example, helium
  • the pressure of hydrogen was detected with the strain gauge 26, if the pressure of hydrogen is detectable, another pressure detection means can be employ

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  • Measuring Fluid Pressure (AREA)

Abstract

A pressure sensor (10) is to be used for detecting a pressure of gas.  The pressure sensor (10) is provided with a metal member (20) which has a hole section (21) with one end opened and the other end bottomed for introducing gas; and a pressure detecting section (26) arranged at a position facing the bottom of the hole section (21) on an outer surface of the metal member (20).  At least at the bottom of the hole section (21), a transmission suppressing film (28) for suppressing transmission of gas is formed.

Description

圧力センサおよびその製造方法Pressure sensor and manufacturing method thereof
　本発明は、気体の圧力を検出する圧力センサに関する。 The present invention relates to a pressure sensor that detects the pressure of a gas.
　高圧な気体の圧力を検出する圧力センサとして、例えば、特許文献１に開示された圧力センサがある。特許文献１に記載の圧力センサは、Ｆｅ－Ｎｉ系や、Ｆｅ－Ｎｉ－Ｃｏ系などの低熱膨張金属からなる金属部材に深い穴が形成された構造を有している。この圧力センサでは、前述した穴に、測定対象となる高圧な気体を導入し、その穴の底部の変形を歪みゲージで検出することで、気体の圧力を測定している。特許文献１に記載の圧力センサは、このような構造の金属部材を採用することにより、高圧な気体に対する耐圧強度を高めている。 As a pressure sensor for detecting the pressure of a high-pressure gas, for example, there is a pressure sensor disclosed in Patent Document 1. The pressure sensor described in Patent Document 1 has a structure in which a deep hole is formed in a metal member made of a low thermal expansion metal such as an Fe—Ni system or an Fe—Ni—Co system. In this pressure sensor, the pressure of the gas is measured by introducing a high-pressure gas to be measured into the above-described hole and detecting the deformation of the bottom of the hole with a strain gauge. The pressure sensor described in Patent Document 1 uses a metal member having such a structure to increase the pressure resistance against high-pressure gas.
　しかし、このような圧力センサによって、高圧な水素ガスの圧力を測定しようとすると、金属部材の内部を水素が透過する現象が生じる場合があった。特に、透過した水素が、金属部材と歪みゲージとの間に滞留すると、滞留した水素の圧力によって、歪みゲージの出力が不安定になるという問題があった。 However, when such a pressure sensor is used to measure the pressure of a high-pressure hydrogen gas, there may be a phenomenon in which hydrogen permeates through the metal member. In particular, when the permeated hydrogen stays between the metal member and the strain gauge, there is a problem that the output of the strain gauge becomes unstable due to the pressure of the staying hydrogen.
　上述した問題に対して、金属部材そのものの材質を変更する手法も考えられる。しかし、金属部材の材質としては、低い膨張率でかつ高強度であることが要求され、水素ガスの圧力を検出する場合には、耐水素脆性をも備えている必要がある。そのため、金属部材の材質そのものを見直すことは大変困難であった。 In order to solve the above-mentioned problem, a method of changing the material of the metal member itself can be considered. However, the material of the metal member is required to have a low expansion coefficient and high strength. When detecting the pressure of hydrogen gas, it is necessary to have hydrogen embrittlement resistance. For this reason, it is very difficult to review the material of the metal member itself.
特公平７－１１４６１号公報Japanese Patent Publication No.7-111461
　このような問題を考慮し、本発明が解決しようとする課題は、金属部材中を透過するおそれの有る気体の圧力を、深い穴を有する金属部材を備えた圧力センサにおいて、精度良く検出することが可能な技術を提供することにある。 In view of such problems, the problem to be solved by the present invention is to accurately detect the pressure of a gas that may permeate through a metal member in a pressure sensor including a metal member having a deep hole. It is to provide a technology that can.
　上記課題を解決するため、本発明の一態様である圧力センサを次のように構成した。 In order to solve the above problems, the pressure sensor which is one aspect of the present invention is configured as follows.
　本発明の一態様である圧力センサは、気体の圧力を検出するために用いられる圧力センサであって、前記気体が導入される穴部であって、一端が開口し他端に底を有する穴部を備えた金属部材と、前記金属部材の外面の、前記穴部の底に対向する位置に設けられた圧力検知部と、を備え、前記穴部の底に、前記気体の透過を抑制する透過抑制膜が形成されている圧力センサである。 A pressure sensor which is one embodiment of the present invention is a pressure sensor used to detect the pressure of a gas, which is a hole into which the gas is introduced, and is a hole having one end opened and the other end having a bottom. A metal member provided with a portion, and a pressure detector provided at a position of the outer surface of the metal member facing the bottom of the hole portion, and suppressing permeation of the gas at the bottom of the hole portion. It is a pressure sensor in which a permeation suppression film is formed.
　このような態様の圧力センサであれば、金属部材に設けられた穴部の底に、気体の透過を抑制する透過抑制膜が形成されている。そのため、金属部材中を透過するおそれの有る気体が、穴部内から圧力検知部に向かって金属部材中を透過することを抑制することができる。この結果、透過した気体によって圧力検知部が圧力を誤検出することが抑制されるので、気体の圧力を精度良く検出することが可能になる。また、上記態様の圧力センサでは、圧力検知部が、金属部材の外面の、穴部の底に対向する位置に設けられているため、透過抑制膜は、少なくとも穴部の底に形成されていればよい。穴部の底以外の部分から気体が透過したとしても、圧力検知部による圧力の検知に対してほとんど影響を与えないからである。よって、上記態様によれば、透過抑制膜を穴部内の全体に形成する必要がないため、製造コストを低減することができる。更に、上記態様であれば、穴部の底に透過抑制膜を形成することで気体の透過を抑制することができるので、金属部材の材質を変更することなく、圧力の検出精度を向上させることができる。 In the case of such a pressure sensor, a permeation suppression film that suppresses the permeation of gas is formed at the bottom of the hole provided in the metal member. Therefore, it is possible to suppress the gas that may permeate through the metal member from permeating through the metal member from the inside of the hole toward the pressure detection unit. As a result, the pressure detection unit is prevented from erroneously detecting the pressure by the permeated gas, so that the gas pressure can be detected with high accuracy. In the pressure sensor of the above aspect, since the pressure detector is provided on the outer surface of the metal member at a position facing the bottom of the hole, the permeation suppression film is formed at least on the bottom of the hole. That's fine. This is because even if gas permeates from a portion other than the bottom of the hole portion, it hardly affects the pressure detection by the pressure detection portion. Therefore, according to the said aspect, since it is not necessary to form a permeation | transmission suppression film | membrane in the whole inside a hole part, manufacturing cost can be reduced. Furthermore, if it is the said aspect, since permeation | transmission of gas can be suppressed by forming a permeation | transmission suppression film | membrane in the bottom of a hole part, it improves pressure detection accuracy, without changing the material of a metal member. Can do.
　上記態様の圧力センサにおいて、前記透過抑制膜は、該透過抑制膜の材料を前記底に溶射することによって形成されていてもよい。このような態様であれば、溶射によって透過抑制膜を形成することができるので、製造コストを低減することができる。 In the pressure sensor of the above aspect, the permeation suppression film may be formed by spraying a material of the permeation suppression film on the bottom. If it is such an aspect, since a permeation | transmission suppression film | membrane can be formed by thermal spraying, manufacturing cost can be reduced.
　上記態様の圧力センサにおいて、前記透過抑制膜は、該透過抑制膜の材料を含むろう材を加熱して前記底に拡散させることで形成されていてもよい。このような態様であれば、ろう付の手法を用いて透過抑制膜を形成することができるので、製造コストを低減することができる。 In the pressure sensor of the above aspect, the permeation suppression film may be formed by heating and brazing a brazing material including the material of the permeation suppression film to the bottom. If it is such an aspect, since a permeation | transmission suppression film | membrane can be formed using the method of brazing, manufacturing cost can be reduced.
　上記態様の圧力センサにおいて、前記透過抑制膜は、アルミニウムを含むものとしてもよい。このような態様であれば、水素の透過を抑制することのできるアルミニウムの性質を利用して、水素ガスが金属部材中を透過することを抑制することができる。 In the pressure sensor of the above aspect, the permeation suppression film may include aluminum. If it is such an aspect, it can suppress that hydrogen gas permeate | transmits the inside of a metallic member using the property of aluminum which can suppress permeation | transmission of hydrogen.
　上記態様の圧力センサにおいて、前記圧力検知部は、前記金属部材の外面に、ガラスによって接着されていてもよい。このような態様であれば、穴部の底に透過抑制膜を形成することによって、気体がガラス内に透過して滞留することを抑制することができる。この結果、このガラスによって接着された圧力検知部による圧力の誤検出を抑制することができる。 In the pressure sensor according to the above aspect, the pressure detection unit may be bonded to the outer surface of the metal member with glass. If it is such an aspect, it can suppress that gas permeate | transmits and retains in glass by forming a permeation | transmission suppression film | membrane in the bottom of a hole part. As a result, it is possible to suppress erroneous detection of pressure by the pressure detection unit bonded by the glass.
　なお、本発明は、上述した圧力センサとしての構成のほか、圧力センサの製造方法や、この圧力センサを備えた燃料電池システム、この燃料電池システムを備えた車両、としても構成することが可能である。 In addition to the configuration as the pressure sensor described above, the present invention can also be configured as a pressure sensor manufacturing method, a fuel cell system including the pressure sensor, and a vehicle including the fuel cell system. is there.
圧力センサ１０を備える燃料電池システム１００の概略構成を示す図である。1 is a diagram illustrating a schematic configuration of a fuel cell system 100 including a pressure sensor 10. FIG. 圧力センサ１０の概略構成を示す断面図である。2 is a cross-sectional view showing a schematic configuration of a pressure sensor 10. FIG. 金属ステム２０の拡大断面図である。3 is an enlarged cross-sectional view of a metal stem 20. FIG. 圧力センサ１０の製造方法の第１実施例を示すフローチャートである。2 is a flowchart showing a first embodiment of a manufacturing method of the pressure sensor 10; 第１実施例における透過抑制膜２８の形成方法を示す図である。It is a figure which shows the formation method of the permeation | transmission suppression film | membrane 28 in 1st Example. 圧力センサ１０の製造方法の第２実施例を示すフローチャートである。4 is a flowchart showing a second embodiment of a method for manufacturing the pressure sensor 10. 第２実施例における透過抑制膜２８の形成方法を示す図である。It is a figure which shows the formation method of the permeation | transmission suppression film | membrane 28 in 2nd Example.
　以下、本発明の実施の形態を次の順序で説明する。
　　Ａ．燃料電池システムの概略構成：
　　Ｂ．圧力センサの構成：
　　Ｃ．第１実施例：
　　Ｄ．第２実施例： Hereinafter, embodiments of the present invention will be described in the following order.
A. General configuration of the fuel cell system:
B. Configuration of pressure sensor:
C. First embodiment:
D. Second embodiment:
　　Ａ．燃料電池システムの概略構成：
　図１は、本発明の実施形態としての圧力センサ１０を備える燃料電池システム１００の概略構成を示す図である。燃料電池システム１００は、２つの水素タンク１１０，１２０を備えている。それぞれの水素タンク１１０，１２０には、分岐管１３０を介して、各水素タンク１１０，１２０に水素ガスを充填するための充填口１３５が接続されている。水素タンク１１０，１２０には、この充填口１３５を通じて、例えば７０ＭＰａの水素ガスが充填される。 A. General configuration of the fuel cell system:
FIG. 1 is a diagram showing a schematic configuration of a fuel cell system 100 including a pressure sensor 10 as an embodiment of the present invention. The fuel cell system 100 includes two hydrogen tanks 110 and 120. The hydrogen tanks 110 and 120 are connected to the hydrogen tanks 110 and 120 through the branch pipes 130 for filling the hydrogen tanks 110 and 120 with hydrogen gas. The hydrogen tanks 110 and 120 are filled with, for example, 70 MPa hydrogen gas through the filling port 135.
　各水素タンク１１０，１２０は、集合管１４０および圧力調整弁１５０を通じて、燃料電池１６０に接続されている。燃料電池１６０は、各水素タンク１１０，１２０から水素ガスの供給を受けるとともに、ブロア等（図示せず）によって空気を導入することで発電を行う。燃料電池システム１００は、例えば、電気自動車に搭載されて、電力源として用いられる。 The hydrogen tanks 110 and 120 are connected to the fuel cell 160 through the collecting pipe 140 and the pressure regulating valve 150. The fuel cell 160 generates power by receiving supply of hydrogen gas from the hydrogen tanks 110 and 120 and introducing air by a blower or the like (not shown). The fuel cell system 100 is mounted on an electric vehicle and used as a power source, for example.
　集合管１４０には、水素タンク１１０，１２０から供給された水素ガスの圧力を検出するための圧力センサ１０が取り付けられている。この圧力センサ１０の出力は、ＥＣＵ（Electronic Control Unit）１７０に入力される。ＥＣＵ１７０は、圧力センサ１０によって検出した水素ガスの圧力に応じて、水素タンク１１０，１２０内の水素ガスの残量を推定する。なお、図１には、水素タンクを２つ示したが、その数は特に限定されない。 The pressure sensor 10 for detecting the pressure of the hydrogen gas supplied from the hydrogen tanks 110 and 120 is attached to the collecting pipe 140. The output of the pressure sensor 10 is input to an ECU (Electronic Control Unit) 170. ECU 170 estimates the remaining amount of hydrogen gas in hydrogen tanks 110 and 120 according to the pressure of hydrogen gas detected by pressure sensor 10. Although two hydrogen tanks are shown in FIG. 1, the number is not particularly limited.
　　Ｂ．圧力センサの構成：
　図２は、圧力センサ１０の概略構成を示す断面図である。圧力センサ１０は、金属ステム２０や、ハウジング３０、ネジ部材４０、コネクタターミナル５０、コネクタケース８０などから構成される。図２には、コネクタケース８０が上方に、ハウジング３０が下方に位置するように圧力センサ１０を示しているが、圧力センサ１０の使用時には、特に方向性はない。 B. Configuration of pressure sensor:
FIG. 2 is a cross-sectional view showing a schematic configuration of the pressure sensor 10. The pressure sensor 10 includes a metal stem 20, a housing 30, a screw member 40, a connector terminal 50, a connector case 80, and the like. Although FIG. 2 shows the pressure sensor 10 so that the connector case 80 is positioned upward and the housing 30 is positioned downward, there is no particular directionality when the pressure sensor 10 is used.
　図３は、金属ステム２０の拡大断面図である。金属ステム２０は、下端が開口し、上端に底を有する穴部２１を備えた略円筒状の部材である。後述するように、この穴部２１には、圧力の検出対象となる水素ガスが導入される。穴部２１の内径は、約２．０～３．０ｍｍであり、その底部は、０．５～１．０ｍｍの薄肉状に形成されている。以下では、薄肉状の底部のことを、ダイアフラム２２と呼ぶ。金属ステム２０の下端側は、上端側に比べて外径が大きく、その間には段部２３が形成されている。金属ステム２０の上端部における側壁の厚みは、４．０～５．０ｍｍである。 FIG. 3 is an enlarged cross-sectional view of the metal stem 20. The metal stem 20 is a substantially cylindrical member having a hole 21 having a lower end opened and a bottom at the upper end. As will be described later, hydrogen gas to be detected in pressure is introduced into the hole 21. The inner diameter of the hole 21 is about 2.0 to 3.0 mm, and its bottom is formed in a thin shape of 0.5 to 1.0 mm. Hereinafter, the thin-walled bottom portion is referred to as a diaphragm 22. The lower end side of the metal stem 20 has an outer diameter larger than that of the upper end side, and a step portion 23 is formed therebetween. The thickness of the side wall at the upper end of the metal stem 20 is 4.0 to 5.0 mm.
　ダイアフラム２２の上面には、センサ基板２４がガラス２５によって接着されている。ガラス２５としては、例えば、硬質ガラスや、鉛ガラス等の低融点ガラスを用いることができる。センサ基板２４には、圧力検知部としての歪みゲージ２６や、この歪みゲージ２６の出力を増幅するためのアンプ回路（図示せず）が実装されている。センサ基板２４の上面は、センサ基板２４から電気信号を出力するボンディングワイヤ（図示せず）を保護するために、シリコンゲル２７で覆われている。 A sensor substrate 24 is bonded to the upper surface of the diaphragm 22 by a glass 25. As the glass 25, for example, hard glass or low-melting glass such as lead glass can be used. On the sensor substrate 24, a strain gauge 26 as a pressure detection unit and an amplifier circuit (not shown) for amplifying the output of the strain gauge 26 are mounted. The upper surface of the sensor substrate 24 is covered with a silicon gel 27 in order to protect a bonding wire (not shown) that outputs an electrical signal from the sensor substrate 24.
　穴部２１の底面には、穴部２１に導入される水素ガスがダイアフラム２２中を透過することを抑制するために、アルミニウムを含む透過抑制膜２８が形成されている。透過抑制膜２８の厚みは、０．０１～０．１ｍｍである。透過抑制膜２８を穴部２１の底面に形成する方法については後述する。 A permeation suppression film 28 containing aluminum is formed on the bottom surface of the hole portion 21 in order to suppress hydrogen gas introduced into the hole portion 21 from passing through the diaphragm 22. The thickness of the permeation suppression film 28 is 0.01 to 0.1 mm. A method of forming the permeation suppression film 28 on the bottom surface of the hole 21 will be described later.
　金属ステム２０は、穴部２１に高圧の水素ガスが導入されることから高強度である必要がある。また、ガラス２５を軟化させてセンサ基板２４を接着することから、熱膨張率が低いことが求められる。そのため、金属ステム２０は、例えば、Ｆｅ－Ｎｉ系合金や、Ｆｅ－Ｎｉ－Ｃｏ系合金等の低熱膨張金属などにより形成することができる。 The metal stem 20 needs to have high strength because high-pressure hydrogen gas is introduced into the hole 21. Moreover, since the glass 25 is softened and the sensor substrate 24 is bonded, it is required that the coefficient of thermal expansion is low. Therefore, the metal stem 20 can be formed of, for example, a low thermal expansion metal such as an Fe—Ni alloy or an Fe—Ni—Co alloy.
　ハウジング３０（図２参照）は、図１に示した集合管１４０に直接的に取り付けられる略円筒状の部材であり、その下方の外周には、集合管１４０への取り付けに用いられるネジ部３１が形成されている。ハウジング３０の内部は、上方から下方にかけて、３段階に内径が細くなる構造を有している。以下では、最も内径の大きい部分を、回路収納部３２といい、２番目に内径の大きい中間部分を、ステム収納部３３という。また、最も内径の小さい下方部分を、気体導入流路３４という。ステム収納部３３の内面には、ネジ部材４０を取り付けるためのネジ山３５が形成されている。ハウジング３０は、例えば、耐食性と高強度を合わせもつ炭素鋼（例えばＳ１５Ｃ等）に耐食性を上げる亜鉛メッキを施したものや、耐食性を有するＸＭ７、ＳＵＳ４３０、ＳＵＳ３０４、ＳＵＳ６３０により形成することができる。 The housing 30 (see FIG. 2) is a substantially cylindrical member that is directly attached to the collecting pipe 140 shown in FIG. 1, and a screw portion 31 used for attachment to the collecting pipe 140 is provided on the outer periphery below the housing 30. Is formed. The interior of the housing 30 has a structure in which the inner diameter is reduced in three stages from the upper side to the lower side. Hereinafter, the portion with the largest inner diameter is referred to as a circuit storage portion 32, and the middle portion with the second largest inner diameter is referred to as a stem storage portion 33. The lower part having the smallest inner diameter is referred to as a gas introduction channel 34. A thread 35 for attaching the screw member 40 is formed on the inner surface of the stem storage portion 33. The housing 30 can be formed by, for example, carbon steel (for example, S15C) having both corrosion resistance and high strength, which is galvanized to increase corrosion resistance, or XM7, SUS430, SUS304, and SUS630 that have corrosion resistance.
　ネジ部材４０は、金属ステム２０の外周を覆う略円筒状の部材である。ネジ部材４０は、例えば、炭素鋼によって形成されている。ネジ部材４０の下方の外周には、前述したステム収納部３３への取り付けに用いられるネジ山４１が形成されている。ネジ部材４０の中央に設けられた筒状部分には、金属ステム２０の段部２３が接触する段部４２が形成されている。このネジ部材４０の段部４２によって、金属ステム２０の段部２３を押さえながら、ネジ部材４０のネジ山４１を、ステム収納部３３に形成されたネジ山３５に螺合させると、金属ステム２０の下面が、ステム収納部３３の底部に接触して、ハウジング３０内に固定される。こうして、金属ステム２０がハウジング３０内に固定されると、金属ステム２０の穴部２１が、ハウジング３０内の気体導入流路３４と連通する。 The screw member 40 is a substantially cylindrical member that covers the outer periphery of the metal stem 20. The screw member 40 is made of, for example, carbon steel. On the outer periphery below the screw member 40, a screw thread 41 used for attachment to the stem storage portion 33 is formed. A cylindrical portion provided in the center of the screw member 40 is formed with a step portion 42 that contacts the step portion 23 of the metal stem 20. When the screw thread 41 of the screw member 40 is screwed into the screw thread 35 formed in the stem housing part 33 while the step part 42 of the metal stem 20 is pressed by the step part 42 of the screw member 40, the metal stem 20. Is fixed in the housing 30 in contact with the bottom of the stem storage portion 33. Thus, when the metal stem 20 is fixed in the housing 30, the hole 21 of the metal stem 20 communicates with the gas introduction channel 34 in the housing 30.
　ネジ部材４０の上部は、椀状に形成されている。この椀状部分の底面には、セラミック基板６０が接着されている。このセラミック基板６０は、金属ステム２０の上面に接着されたセンサ基板２４とボンディングワイヤ６１によって電気的に接続されている。セラミック基板６０には、センサ基板２４から入力される信号に対して所定の信号処理を加えるためのＩＣチップ６２が実装されている。また、セラミック基板６０には、ＩＣチップ６２と導通するピン６３が立設されている。 The upper part of the screw member 40 is formed in a bowl shape. A ceramic substrate 60 is bonded to the bottom surface of the bowl-shaped portion. The ceramic substrate 60 is electrically connected to the sensor substrate 24 bonded to the upper surface of the metal stem 20 by bonding wires 61. On the ceramic substrate 60, an IC chip 62 for performing predetermined signal processing on a signal input from the sensor substrate 24 is mounted. The ceramic substrate 60 is provided with pins 63 that are electrically connected to the IC chip 62.
　コネクタターミナル７０は、金属端子７２を樹脂にインサート成形して構成された部材である。このコネクタターミナル７０は、ネジ部材４０の椀状部分の上部に嵌め込まれる。金属端子７２は、レーザ溶接等によって、セラミック基板６０上に設けられたピン６３に接合されている。なお、金属端子７２は、図２では１本だけ示しているが、センサ基板２４やセラミック基板６０への電源供給に用いられる端子や、信号出力に用いられる端子、接地のために用いられる端子など、複数本が設けられている。 The connector terminal 70 is a member formed by insert molding the metal terminal 72 into resin. The connector terminal 70 is fitted into the upper part of the hook-shaped portion of the screw member 40. The metal terminal 72 is joined to a pin 63 provided on the ceramic substrate 60 by laser welding or the like. Although only one metal terminal 72 is shown in FIG. 2, a terminal used for power supply to the sensor substrate 24 and the ceramic substrate 60, a terminal used for signal output, a terminal used for grounding, etc. A plurality of lines are provided.
　コネクタケース８０は、金属端子７２の周囲を囲む部材である。コネクタケース８０は、Ｏリング９０を介してハウジング３０の上端の開口部に挿入される。このとき、ハウジング３０の上端が内側にかしめられ、コネクタケース８０は、ハウジング３０の上部に一体的に固定される。 The connector case 80 is a member surrounding the periphery of the metal terminal 72. The connector case 80 is inserted into the opening at the upper end of the housing 30 via the O-ring 90. At this time, the upper end of the housing 30 is caulked inward, and the connector case 80 is integrally fixed to the upper portion of the housing 30.
　以上のように構成された圧力センサ１０では、ハウジング３０に設けられた気体導入流路３４を通じて、水素タンク１１０，１２０から、金属ステム２０の穴部２１に、最大７０ＭＰａの高圧水素が導入される。すると、この水素ガスの圧力によってダイアフラム２２が変形する。ダイアフラム２２が変形すると、その上面に接着されたセンサ基板２４に実装されている歪みゲージ２６も変形する。すると、歪みゲージ２６からは、その変形度合いに応じた電気信号が出力され、センサ基板２４、セラミック基板６０、および、金属端子７２を通じて、その電気信号がＥＣＵ１７０に伝達される。ＥＣＵ１７０は、この電気信号に応じて、水素タンク１１０，１２０から供給される水素ガスの圧力を検出する。 In the pressure sensor 10 configured as described above, high-pressure hydrogen of a maximum of 70 MPa is introduced from the hydrogen tanks 110 and 120 into the hole 21 of the metal stem 20 through the gas introduction channel 34 provided in the housing 30. . Then, the diaphragm 22 is deformed by the pressure of the hydrogen gas. When the diaphragm 22 is deformed, the strain gauge 26 mounted on the sensor substrate 24 bonded to the upper surface of the diaphragm 22 is also deformed. Then, an electrical signal corresponding to the degree of deformation is output from the strain gauge 26, and the electrical signal is transmitted to the ECU 170 through the sensor substrate 24, the ceramic substrate 60, and the metal terminal 72. The ECU 170 detects the pressure of the hydrogen gas supplied from the hydrogen tanks 110 and 120 in accordance with this electrical signal.
　　Ｃ．第１実施例： 
　図４は、圧力センサ１０の製造方法の第１実施例を示すフローチャートである。本実施例の製造方法では、まず、穴部２１を形成した金属ステム２０を用意し（ステップＳ１０）、この穴部２１の底面に対して、溶射によってアルミニウムを含む透過抑制膜２８を形成する（ステップＳ２０）。 C. First embodiment:
FIG. 4 is a flowchart showing a first embodiment of a manufacturing method of the pressure sensor 10. In the manufacturing method of the present embodiment, first, a metal stem 20 having a hole 21 is prepared (step S10), and a permeation suppression film 28 containing aluminum is formed on the bottom surface of the hole 21 by thermal spraying ( Step S20).
　図５は、第１実施例における透過抑制膜２８の形成方法を示す図である。本実施例では、図５に示すように、金属ステム２０の穴部２１の底面に、溶射装置２００を用いて、厚みが０．０１～０．１ｍｍの透過抑制膜２８を形成する。厚みをこのように制限したのは、０．０１ｍｍよりも薄いと、高圧水素の導入によって透過抑制膜２８が破れてしまう可能性があるためであり、０．１ｍｍよりも厚いと、歪みゲージ２６の感度に影響を与える可能性があるためである。なお、溶射によって穴部２１の底面以外に形成された膜（例えば、金属ステム２０の底面に形成された膜）は、切削等の機械加工によって除去する。 FIG. 5 is a diagram showing a method of forming the permeation suppression film 28 in the first embodiment. In this embodiment, as shown in FIG. 5, a permeation suppression film 28 having a thickness of 0.01 to 0.1 mm is formed on the bottom surface of the hole 21 of the metal stem 20 by using a thermal spraying apparatus 200. The reason for limiting the thickness in this way is that if it is thinner than 0.01 mm, the permeation suppression film 28 may be broken by the introduction of high-pressure hydrogen. If it is thicker than 0.1 mm, the strain gauge 26 This is because there is a possibility of affecting the sensitivity. In addition, the film | membrane (for example, film | membrane formed in the bottom face of the metal stem 20) formed other than the bottom face of the hole part 21 by thermal spraying is removed by machining, such as cutting.
　透過抑制膜２８の材料としては、アルミニウムのほか、アルミニウム合金や、オーステナイト系ステンレス鋼、セラミック等を用いることができる。アルミニウムやアルミニウム合金は、水素分子を化学吸着しない性質を有しているため、水素ガスの透過を抑制することができる。また、ＳＵＳ３１６Ｌ等のオーステナイト系ステンレス鋼は、水素を吸収するものの、その内部への水素の拡散が著しく遅いという性質を有しているため、実質的に水素ガスの透過を抑制することが可能になる。また、炭化物、酸化物、窒化物などのセラミック膜は、水素分子を吸着する性質や解離させる性質がなく、金属のように原子状の水素を拡散させる性質もない。そのため、セラミック膜を形成することによっても、水素ガスの透過を抑制することができる。 As a material for the permeation suppression film 28, aluminum, aluminum alloy, austenitic stainless steel, ceramic, or the like can be used. Since aluminum and aluminum alloys have the property of not chemically adsorbing hydrogen molecules, the permeation of hydrogen gas can be suppressed. In addition, austenitic stainless steel such as SUS316L absorbs hydrogen, but has a property that diffusion of hydrogen into the inside thereof is extremely slow, so that hydrogen gas permeation can be substantially suppressed. Become. In addition, ceramic films such as carbides, oxides, and nitrides do not have the property of adsorbing or dissociating hydrogen molecules, nor the property of diffusing atomic hydrogen like metal. Therefore, the permeation of hydrogen gas can also be suppressed by forming a ceramic film.
　溶射方法としては、例えば、火炎溶射、ＨＶＯＦ（High Velocity Oxygen Fuel）溶射、プラズマ溶射などを適用することができる。上述した透過抑制膜２８のどの材料に対しても、これらの溶射方法を適用可能であるが、透過抑制膜２８と金属ステム２０との密着性を考慮すると、火炎溶射よりも、より高温、高速に溶射が可能なＨＶＯＦ溶射が好適である。また、セラミック膜を形成する場合には、数万度もの高温で溶射可能なプラズマ溶射を採用することが好適である。 As the thermal spraying method, for example, flame spraying, HVOF (High-Velocity-Oxygen-Fuel) spraying, plasma spraying, or the like can be applied. Although these spraying methods can be applied to any material of the permeation suppression film 28 described above, considering the adhesion between the permeation suppression film 28 and the metal stem 20, higher temperature and higher speed than flame spraying. HVOF spraying that can be sprayed on is suitable. Further, when forming a ceramic film, it is preferable to employ plasma spraying that can be sprayed at a high temperature of several tens of thousands of degrees.
　以上のようにして、溶射によって金属ステム２０の穴部２１の底面に透過抑制膜２８を形成すると、続いて、ダイアフラム２２の上面に、歪みゲージ２６が実装されたセンサ基板２４をガラス２５によって接着する（ステップＳ３０）。そして、最後に、ネジ部材４０によって金属ステム２０をハウジング３０内に取り付け、更に、コネクタターミナル７０とコネクタケース８０とをハウジング３０に取り付けることで、圧力センサ１０を組み立てる（ステップＳ４０）。 As described above, when the permeation suppression film 28 is formed on the bottom surface of the hole portion 21 of the metal stem 20 by thermal spraying, the sensor substrate 24 on which the strain gauge 26 is mounted is subsequently adhered to the upper surface of the diaphragm 22 by the glass 25. (Step S30). Finally, the metal stem 20 is attached to the housing 30 by the screw member 40, and the connector terminal 70 and the connector case 80 are attached to the housing 30 to assemble the pressure sensor 10 (step S40).
　以上のように製造された圧力センサ１０において、金属ステム２０中のダイアフラム２２部分は、金属ステム２０の中で最も薄い部分であるため、水素が最も透過しやすい部分である。しかし、本実施例では、金属ステム２０の穴部２１の底面、すなわち、ダイアフラム２２の内面に、透過抑制膜２８を形成する。そのため、穴部２１内に高圧の水素ガスを導入しても、その水素が、ダイアフラム２２内を透過することが抑制される。この結果、水素が、金属ステム２０と歪みゲージ２６との間に存在するガラス２５等に滞留することが抑制されるため、歪みゲージ２６の出力が安定し、水素ガスの圧力を精度良く検出することが可能になる。 In the pressure sensor 10 manufactured as described above, the diaphragm 22 portion in the metal stem 20 is the thinnest portion in the metal stem 20, so that hydrogen is most easily permeable. However, in this embodiment, the permeation suppression film 28 is formed on the bottom surface of the hole 21 of the metal stem 20, that is, on the inner surface of the diaphragm 22. For this reason, even if high-pressure hydrogen gas is introduced into the hole 21, the hydrogen is suppressed from permeating through the diaphragm 22. As a result, the hydrogen is suppressed from staying in the glass 25 or the like existing between the metal stem 20 and the strain gauge 26, so that the output of the strain gauge 26 is stabilized and the pressure of the hydrogen gas is accurately detected. It becomes possible.
　また、本実施例の金属ステム２０には、そのダイアフラム２２の上面に歪みゲージ２６が配置されているため、ダイアフラム２２の下面にあたる穴部２１の底部のみに透過抑制膜２８を形成している。これは、他の部分（例えば、穴部２１の側壁）から水素が透過したとしても、歪みゲージ２６によるダイアフラム２２の変形の検出に与える影響が無視し得る程度だからである。このように、本実施例では、穴部２１内の全体に透過抑制膜２８を形成する必要がないので、溶射法によって効率よく透過抑制膜２８を形成することができる。また、溶射法を用いれば、大気雰囲気において、短時間で密着性の高い透過抑制膜２８を形成することができるので、製造コストを削減することが可能になる。更に、本実施例によれば、透過抑制膜２８を形成することで水素の透過を抑制することができるので、金属部材２０の材質を変更することなく、圧力の検出精度を向上させることができる。 Further, since the strain gauge 26 is disposed on the upper surface of the diaphragm 22 in the metal stem 20 of the present embodiment, the permeation suppression film 28 is formed only on the bottom portion of the hole portion 21 corresponding to the lower surface of the diaphragm 22. This is because even if hydrogen permeates from other parts (for example, the side wall of the hole 21), the influence of the strain gauge 26 on the detection of the deformation of the diaphragm 22 is negligible. As described above, in this embodiment, since it is not necessary to form the permeation suppression film 28 in the whole hole portion 21, the permeation suppression film 28 can be efficiently formed by a thermal spraying method. Further, if the thermal spraying method is used, the permeation suppression film 28 having high adhesion can be formed in an air atmosphere in a short time, so that the manufacturing cost can be reduced. Furthermore, according to the present embodiment, since the permeation of hydrogen can be suppressed by forming the permeation suppressing film 28, the pressure detection accuracy can be improved without changing the material of the metal member 20. .
　　Ｄ．第２実施例： 
　上述した第１実施例では、溶射によって、金属ステム２０の穴部２１の底に透過抑制膜２８を形成した。これに対して、第２実施例では、ろう付の手法を用いて透過抑制膜２８を形成する。 D. Second embodiment:
In the first embodiment described above, the permeation suppression film 28 is formed on the bottom of the hole 21 of the metal stem 20 by thermal spraying. In contrast, in the second embodiment, the permeation suppression film 28 is formed using a brazing technique.
　図６は、圧力センサ１０の製造方法の第２実施例を示すフローチャートである。本実施例の製造方法は、図４に示した第１実施例の製造方法に対して、ステップＳ２０ｂにおける透過抑制膜２８の形成方法のみが異なる。そのため、ステップＳ２０ｂ以外の工程（ステップＳ１０，Ｓ３０，Ｓ４０）については説明を省略する。 FIG. 6 is a flowchart showing a second embodiment of the manufacturing method of the pressure sensor 10. The manufacturing method of this embodiment is different from the manufacturing method of the first embodiment shown in FIG. 4 only in the method of forming the permeation suppression film 28 in step S20b. Therefore, the description of steps (steps S10, S30, S40) other than step S20b is omitted.
　図７は、本実施例における透過抑制膜２８の形成方法を示す図である。図７に示すように、本実施例では、まず、金属ステム２０の穴部２１の開口部を上方に向け、穴部２１の内面を洗浄する。具体的には、汚れを取り除いた上で、酸洗等によって酸化膜を除去する。そして、洗浄後の穴部２１内に、ろう材としてアルミろうをセットし、無酸素雰囲気において加熱する。すると、ろう材が融解し、穴部２１の底面に拡散して透過抑制膜２８が形成される。 FIG. 7 is a diagram showing a method of forming the permeation suppression film 28 in this example. As shown in FIG. 7, in this embodiment, first, the opening of the hole 21 of the metal stem 20 is directed upward, and the inner surface of the hole 21 is cleaned. Specifically, after removing dirt, the oxide film is removed by pickling or the like. Then, aluminum brazing is set as a brazing material in the cleaned hole 21 and heated in an oxygen-free atmosphere. Then, the brazing material is melted and diffused to the bottom surface of the hole portion 21 to form a permeation suppression film 28.
　ろう材としては、アルミろうのほか、金ろうや銀ろう、はんだ、などを用いることができる。金ろうを用いれば、長期的に安定した性質を有する透過抑制膜２８を形成することができる。また、銀ろうは濡れ性が良いため、穴部２１の底面に良好に拡散させることができる。銀ろうとしては、例えば、Ａｇ－Ｃｕ－Ｓｎ系の銀ろうや、Ａｇ－Ｃｕ－Ｚｎ－Ｃｄ系、Ａｇ－Ｃｕ－Ｚｎ－Ｓｎ系の銀ろうを用いることができる。Ａｇ－Ｃｕ－Ｓｎ系の銀ろうは、蒸気圧が低く、蒸発し易い性質のため、炉中ろう付に適している。また、Ａｇ－Ｃｕ－Ｚｎ－Ｃｄ系やＡｇ－Ｃｕ－Ｚｎ－Ｓｎ系の銀ろうであれば、蒸気圧が高く、蒸発し難い性質のため、トーチろう付に適している。また、Ｐｂ－Ｓｎ系やＳｎ－Ａｇ系のはんだをろう材として用いれば、融点が低いため、容易に透過抑制膜２８を形成することが可能になる。 As the brazing material, aluminum brazing, gold brazing, silver brazing, solder, etc. can be used. If gold brazing is used, it is possible to form the permeation suppression film 28 having a long-term stable property. In addition, since silver solder has good wettability, it can be diffused well on the bottom surface of the hole 21. As the silver solder, for example, an Ag—Cu—Sn silver solder, an Ag—Cu—Zn—Cd silver solder, an Ag—Cu—Zn—Sn silver solder can be used. Ag-Cu-Sn-based silver brazing is suitable for brazing in a furnace because of its low vapor pressure and easy evaporation. Further, Ag-Cu-Zn-Cd and Ag-Cu-Zn-Sn-based silver brazing are suitable for torch brazing because of their high vapor pressure and difficulty in evaporation. If a Pb—Sn or Sn—Ag solder is used as the brazing material, the permeation suppression film 28 can be easily formed because the melting point is low.
　Ａｌ（アルミニウム）、Ｃｕ（銅）、Ａｇ（銀）、Ｃｄ（カドミウム）、Ｓｎ（スズ）、Ａｕ（金）、Ｐｂ（鉛）などの金属は、その価電子構造により、水素分子と共有結合しにくく、水素が吸着されにくいという性質を有する。これらの金属は、一般的なろう材（はんだを含む）に多く含まれている。そこで、本実施例では、これらの金属を含むろう材を用いて透過抑制膜２８を形成することで、低コストに圧力センサ１０を製造することができる。 Metals such as Al (aluminum), Cu (copper), Ag (silver), Cd (cadmium), Sn (tin), Au (gold), and Pb (lead) are covalently bonded to hydrogen molecules due to their valence structure. It has the property that it is difficult to adsorb and hydrogen is not easily adsorbed. Many of these metals are contained in general brazing materials (including solder). Therefore, in this embodiment, the pressure sensor 10 can be manufactured at low cost by forming the permeation suppression film 28 using the brazing material containing these metals.
　また、金ろうは、融点が９５０℃程度、銀ろうは、６５０～８００℃、アルミろうは６００℃程度、はんだは１９０～２５０℃である。そのため、透過抑制膜２８の材料としてろう材を用いれば、圧力センサ１０の製造ライン上、最も都合の良いろう材を選択することが可能になる。 Also, the melting point of gold brazing is about 950 ° C., silver brazing is 650 to 800 ° C., aluminum brazing is about 600 ° C., and solder is 190 to 250 ° C. Therefore, if a brazing material is used as the material of the permeation suppression film 28, the most convenient brazing material can be selected on the production line of the pressure sensor 10.
　以上、本発明の種々の実施例について説明したが、本発明はこれらの実施例に限定されず、その趣旨を逸脱しない範囲で種々の構成を採ることが可能である。例えば、上記実施例では、圧力センサ１０は、燃料電池システム１００の集合管１４０に取り付けられることとしたが、水素タンク１１０，１２０に直接取り付けられていてもよい。また、圧力調整弁１５０よりも下流側の配管に取り付けられていてもよい。また、圧力センサ１０は、水素の圧力を測定するために用いられるだけではなく、金属ステム２０を透過する可能性のある気体（例えば、ヘリウム）の圧力を測定するために用いてもよい。その他、上記実施例では、歪みゲージ２６によって水素の圧力を検知することとしたが、水素の圧力を検知可能であれば、他の圧力検知手段を適宜採用することが可能である。 Although various embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various configurations can be adopted without departing from the spirit of the present invention. For example, in the above embodiment, the pressure sensor 10 is attached to the collecting pipe 140 of the fuel cell system 100, but may be directly attached to the hydrogen tanks 110 and 120. Further, it may be attached to piping downstream of the pressure regulating valve 150. Further, the pressure sensor 10 is not only used for measuring the pressure of hydrogen, but may be used for measuring the pressure of a gas (for example, helium) that may permeate the metal stem 20. In addition, in the said Example, although the pressure of hydrogen was detected with the strain gauge 26, if the pressure of hydrogen is detectable, another pressure detection means can be employ | adopted suitably.

Claims (7)

  1. 　気体の圧力を検出するために用いられる圧力センサであって、
    　前記気体が導入される穴部であって、一端が開口し他端に底を有する穴部を備えた金属部材と、
    　前記金属部材の外面の、前記穴部の底に対向する位置に設けられた圧力検知部と、
    　を備え、
    　少なくとも前記穴部の底に、前記気体の透過を抑制する透過抑制膜が形成されている
    　圧力センサ。     A pressure sensor used to detect the pressure of a gas,
    A metal member having a hole into which the gas is introduced, the hole having one end opened and the other end having a bottom;
    A pressure detector provided on the outer surface of the metal member at a position facing the bottom of the hole;
    With
    A pressure sensor, wherein a permeation suppression film that suppresses permeation of the gas is formed at least on the bottom of the hole.
  2. 　請求項１に記載の圧力センサであって、
    　前記透過抑制膜は、該透過抑制膜の材料を前記底に溶射することによって形成されている、圧力センサ。     The pressure sensor according to claim 1,
    The permeation suppression film is a pressure sensor formed by spraying a material of the permeation suppression film on the bottom.
  3. 　請求項１に記載の圧力センサであって、
    　前記透過抑制膜は、該透過抑制膜の材料を含むろう材を加熱して前記底に拡散させることで形成されている、圧力センサ。     The pressure sensor according to claim 1,
    The said permeation | transmission suppression film | membrane is a pressure sensor currently formed by heating the brazing | wax material containing the material of this permeation | transmission suppression film | membrane, and making it diffuse to the said bottom.
  4. 　請求項１ないし請求項３のいずれか一項に記載の圧力センサであって、
    　前記透過抑制膜は、アルミニウムを含む、圧力センサ。     The pressure sensor according to any one of claims 1 to 3,
    The permeation suppression film is a pressure sensor containing aluminum.
  5. 　請求項１ないし請求項４のいずれか一項に記載の圧力センサであって、
    　前記圧力検知部は、前記金属部材の外面に、ガラスによって接着されている、圧力センサ。     The pressure sensor according to any one of claims 1 to 4,
    The pressure sensor is a pressure sensor bonded to the outer surface of the metal member with glass.
  6. 　請求項１ないし請求項５のいずれか一項に記載の圧力センサであって、
    　前記気体は、水素ガスである、圧力センサ。     The pressure sensor according to any one of claims 1 to 5,
    The pressure sensor, wherein the gas is hydrogen gas.
  7. 　気体の圧力を検出するために用いられる圧力センサの製造方法であって、
    　前記気体が導入される穴であって、一端が開口し他端に底を有する穴部を備えた金属部材を用意する工程と、
    　少なくとも前記穴部の底に、前記気体の透過を抑制する透過抑制膜を形成する工程と、
    　前記金属部材の外面の、前記穴部の底に対向する位置に、圧力検知部を設ける工程と
    　を備える製造方法。     A method of manufacturing a pressure sensor used to detect the pressure of a gas,
    A step of preparing a metal member having a hole into which the gas is introduced, the hole having one end opened and the other end having a bottom;
    Forming a permeation suppressing film for suppressing permeation of the gas at least at the bottom of the hole;
    A step of providing a pressure detection portion at a position of the outer surface of the metal member facing the bottom of the hole.
PCT/JP2009/002829 2009-06-22 2009-06-22 Pressure sensor and method for manufacturing the same WO2010150302A1 (en)

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Publication number Priority date Publication date Assignee Title
JP2014011460A (en) * 2012-06-28 2014-01-20 Kojun Seimitsu Kogyo Kofun Yugenkoshi Method of producing metal element

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JPS62151732A (en) * 1985-12-26 1987-07-06 Nippon Soken Inc Joining structure for diamond body to metal body
JPH01249294A (en) * 1988-03-29 1989-10-04 Nippon Stainless Steel Co Ltd Precoated brazing filler metal-coated metal sheet, production thereof and using method therefor
JPH10132691A (en) * 1996-10-31 1998-05-22 Hitachi Ltd Diaphragm
JP2005114453A (en) * 2003-10-06 2005-04-28 Yokogawa Electric Corp Differential pressure measuring system
JP2006038538A (en) * 2004-07-23 2006-02-09 Nagano Keiki Co Ltd Pressure sensor

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Publication number Priority date Publication date Assignee Title
JPS62151732A (en) * 1985-12-26 1987-07-06 Nippon Soken Inc Joining structure for diamond body to metal body
JPH01249294A (en) * 1988-03-29 1989-10-04 Nippon Stainless Steel Co Ltd Precoated brazing filler metal-coated metal sheet, production thereof and using method therefor
JPH10132691A (en) * 1996-10-31 1998-05-22 Hitachi Ltd Diaphragm
JP2005114453A (en) * 2003-10-06 2005-04-28 Yokogawa Electric Corp Differential pressure measuring system
JP2006038538A (en) * 2004-07-23 2006-02-09 Nagano Keiki Co Ltd Pressure sensor

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2014011460A (en) * 2012-06-28 2014-01-20 Kojun Seimitsu Kogyo Kofun Yugenkoshi Method of producing metal element

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