Gas sensor module

Abstract

To provide a gas sensor module capable of suppressing intrusion of water into a gas sensor.SOLUTION: A gas sensor module (1) includes a container (10) formed of a plurality of surfaces and having an internal space, a gas sensor (2) having an opening (21) for taking in a detection target gas, a substrate (3) having an electric circuit (31) electrically connected to the gas sensor, and a waterproof molded body (4) covering at least a part of the gas sensor and the substrate. The container (10) houses the gas sensor and the substrate in an internal space (IS), and includes a gas introduction port (17) for introducing the detection target gas into the internal space, and a drain port for draining water entering the internal space. The opening (21) of the gas sensor and one surface (13) of the container face each other, and the opening and the gas introduction port of the container are arranged so as not to face each other.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a gas sensor module, and more particularly to a gas sensor module that requires water resistance. [Background technology]

[0002] Gas sensors are sometimes required to detect gas in environments where water may get in. Japanese Patent Application Laid-Open No. 2011-53123 (Patent Document 1) discloses a gas sensor module that improves the waterproof performance of a gas sensor by housing the gas sensor in a container. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-53123 Summary of the Invention [Problem to be solved by the invention]

[0004] A gas sensor requires that the gas to be detected be introduced into the sensor. Therefore, the gas sensor cannot be completely sealed in a container. The container in Patent Document 1 has a gas introduction opening located opposite the opening of the gas sensor, which may allow water to enter the gas sensor.

[0005] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a gas sensor module that can prevent water from entering the gas sensor. [Means for solving the problem]

[0006] A gas sensor module according to one aspect of the present invention includes a container formed with multiple surfaces and having an internal space, a gas sensor having an opening for introducing a target gas, a substrate having an electric circuit electrically connected to the gas sensor, and a waterproof molded article covering at least a portion of the gas sensor and the substrate. The container accommodates the gas sensor and the substrate in the internal space and includes a gas inlet for introducing the target gas into the internal space and a drain port for draining water that enters the internal space. The opening of the gas sensor faces one surface of the container, and the opening and the gas inlet of the container are positioned so as not to face each other.

[0007] Preferably, an opposing surface, which is one surface of the container facing the opening, is located below the opening of the gas sensor, and the gas inlet is provided on the opposing surface.

[0008] Preferably, the gas to be detected is a gas that is heavier than air.

[0009] Preferably, a gap of 2.0 mm or more is provided between the opening of the gas sensor and the opposing surface.

[0010] Preferably, the container further includes a vent for introducing the target gas into the internal space. 2 4mm or more 2 The following is the result.

[0011] Preferably, the opening area of ​​the gas inlet is 3 mm 2 More than 30mm 2 The following is the result.

[0012] Preferably, the drain hole is provided on the opposite surface of the container. The opening area of ​​the drain hole is 1.5 mm 2 Over 4.0mm 2 The following is the result.

[0013] A method for manufacturing a gas sensor module according to one aspect of the present invention includes the steps of: preparing a container having an internal space formed by multiple surfaces, a gas sensor having an opening for introducing a target gas to be detected, and a substrate having an electric circuit electrically connected to the gas sensor; forming a gas inlet for introducing the target gas to the internal space and a drainage outlet for draining water that has entered the internal space in the container; forming an assembly including the gas sensor and the substrate; forming a waterproof molded body by hot melt molding so as to cover a desired region of the assembly; and accommodating the assembly covered with the waterproof molded body in the container. In the accommodating step, the opening of the gas sensor faces one surface of the container, but the opening and the gas inlet of the container are not opposed to each other. [Effects of the Invention]

[0014] According to the present invention, it is possible to provide a gas sensor module that can prevent water from entering the gas sensor. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a front view showing a gas sensor module according to an embodiment of the present invention; [Figure 2] FIG. 2 is a bottom view showing the gas sensor module according to the embodiment of the present invention. [Figure 3] 1 is a front view showing a state in which the front surface is removed from a gas sensor module according to an embodiment of the present invention. [Figure 4] FIG. 2 is a front view showing an assembly according to an embodiment of the present invention. [Figure 5] 1 is a front cross-sectional view showing a gas sensor according to an embodiment of the present invention. [Figure 6] FIG. 2 is an explanatory view showing a gas flow path in the gas sensor module according to the embodiment of the present invention. [Figure 7] 5 is a flowchart illustrating a method for manufacturing a gas sensor module according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0016] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the accompanying drawings, in which the same or corresponding parts are designated by the same reference numerals and will not be described repeatedly.

[0017] (About the composition) The overall configuration of a gas sensor module 1 according to this embodiment will be described with reference to Figures 1 to 3. The gas sensor module 1 comprises a container 10 formed of multiple surfaces 12 to 16 and having an internal space IS, a gas sensor 2 having an opening 21 for introducing a gas to be detected, a substrate 3 having an electric circuit 31 electrically connected to the gas sensor 2, and a waterproof molded body 4 covering at least a portion of the gas sensor 2 and the substrate 3. For ease of understanding, the drawings show the up-down direction, the left-right direction, and the front-rear direction. In the description of this specification, the up-down direction is synonymous with the vertical direction.

[0018] The container 10 includes a housing portion 11 having an internal space IS capable of housing the gas sensor 2 and the substrate 3, and a front surface 12 covering the internal space IS. The shape of the container 10 is typically a substantially rectangular shape with an open front, but is not particularly limited as long as it can house the gas sensor 2 and the substrate 3 inside. Therefore, the container 10 may be cylindrical or polygonal.

[0019] The container 10 is formed from, for example, a resin material, a glass material such as ceramic, or a composite material in which a filler is mixed into a resin. The resin material is typically a thermoplastic resin, but can be selected from a variety of materials, such as polypropylene, ABS, polyethylene terephthalate, polycarbonate, PBT (polybutylene terephthalate), polyamide, PE (polyethylene), POM (polyoxymethylene), Teflon (registered trademark), and acrylic.

[0020] The storage unit 11 of this embodiment is a rectangular housing formed by a bottom surface 13, side surfaces 14, a top surface 15, and a rear surface 16, which are plate-like members (see FIG. 3). Each of the multiple surfaces 13 to 16 is distinguished by its relative position with respect to the storage space IS as the center, as shown in the directions in the drawings.

[0021] The front surface 12 is a plate-like member formed to openably cover the front surface of the storage section 11. Here, the installation direction of the container 10 of this embodiment is predetermined, and the container 10 is installed so that the arrow on the front surface 12 points upward.

[0022] The lower surface 13 of this embodiment can also be considered as an "opposing surface 13" that faces the opening 21 of the gas sensor 2. The opposing surface 13 is located below the opening 21 of the gas sensor. A protrusion (not shown) may be provided on the inner wall of the opposing surface 13 to prevent moisture from entering the opening 21. The protrusion may have various shapes, such as a curved shape or a tapered shape.

[0023] The container 10 also has a gas inlet 17 for introducing the target gas into the internal space, a drain outlet 18 for draining water that enters the container 10, and an air vent 19 for distributing the target gas throughout the container 10.

[0024] The gas inlet 17 in this embodiment is provided on the opposing surface 13. The gas inlet 17 is positioned so as not to overlap with the opening 21 of the gas sensor 2 in the vertical direction. This prevents water that has entered through the gas inlet 17 from adhering to the opening 21 of the gas sensor. The gas inlet 17 in this embodiment is provided on the bottom surface 13 of the container because the gas sensor 2 detects "gases heavier than air (hereinafter also referred to as "target gases"). This is because gases heavier than air tend to accumulate in the lower region inside the device (in which the gas sensor is mounted). However, the position of the gas inlet 17 can be changed as appropriate depending on the type of target gas and the installation position of the gas sensor module.

[0025] The shape of the gas inlet 17 is not particularly limited, but is typically circular. The opening area of ​​the gas inlet 17 is 3 mm 2 More than 30mm 2 Less than 3mm 2 If the opening area is less than 3 mm, it may be difficult to take in the target gas, which may result in poor accuracy. 2 More than 20mm 2 The following is preferred:

[0026] Gas inlet 17 may have a ring-shaped protrusion 17a that protrudes from the outside of container 10. Protrusion 17a protrudes downward from bottom surface 13. Protrusion 17a is the part to which a gas introduction tube for a quality inspection device is attached, and also serves the function of preventing water splashing up from below from entering the gas sensor.

[0027] The drain outlets 18 are openings provided on the underside 13 to drain water that has entered the internal space IS. From the viewpoint of preventing water from adhering to the opening 21 of the gas sensor 2, it is preferable that the drain outlets 18 be provided at a position on the opposing surface 13 that does not overlap the opening 21 in the vertical direction. In this embodiment, the drain outlets 18 are elongated holes, and two drain outlets 18 are provided on the opposing surface 13, separated by an area that overlaps with the opening 21. The shape of the drain outlets 18 is not particularly limited as long as they can properly drain water, and various shapes such as rectangular or circular can be used. The number of drain outlets may be one or more. The drain outlets 18 can also function as "vents" to promote air circulation within the internal space IS.

[0028] The opening area of ​​the drain port 18 is 1.5 mm 2 Over 4.0mm 2 It is less than 1.5mm 2 If the opening area is less than 2.0 mm, surface tension may be generated, preventing water from being properly drained. 2 More than 3.5mm 2 The following is preferred:

[0029] The vents 19 are openings for supporting the supply of air containing the target gas from the gas inlet 17 and are provided on at least one surface other than the opposing surface 13. While the shape and number of the vents 19 are not particularly limited, the vents 19 in this embodiment are elongated holes, and three are provided on the front surface 12. From the perspective of diffusing the target gas into the internal space IS of the container 10, it is preferable that the vents 19 be provided in the upper region as much as possible. Here, the "upper region" refers to the region above the center of the container 10 in the vertical direction. If the openings of the container 10 (gas inlet 17, drain 18) were only on the bottom surface, the air within the container 10 would not circulate sufficiently, potentially delaying detection of the target gas. The provision of the vents 19 allows for smooth air circulation within the container 10, thereby enabling early detection of the target gas despite a simple configuration.

[0030] The opening area of ​​the vent 19 is 0.5 mm 2 4mm or more 2 From the viewpoint of waterproofing, the opening area of ​​the ventilation hole 19 is preferably 0.5 mm 2 Over 2.0mm 2 This allows the surface tension to come into play when water adheres to the opening, preventing water from entering.

[0031] The container 10 of this embodiment can be attached to the inside of a device that handles the gas to be detected by various methods, such as adhesive fixation, screw fastening, etc. In this embodiment, the container is attached by inserting a screw into a hole in the attachment portion (no reference numeral).

[0032] 5, the gas sensor 2 includes a gas sensing element 22 that detects a detection target gas, a cap 20 that covers the gas sensing element 22, a mesh portion 21 provided at an opening of the cap 22, a connection terminal 24 that electrically connects the gas sensing element 22 and the substrate 3, and an adsorption portion 25 filled in the cap 20. Fig. 5 is a cross-sectional view showing the gas sensor 2 of this embodiment.

[0033] The gas sensor 2 of this embodiment detects a gas heavier than air (average molecular weight 28.8) as a detection target gas. In other words, the density of the detection target gas of the gas sensor 2 is greater than the density of air. As the detection target gas, refrigerant gases can be particularly suitably detected, and various gases can be detected, such as carbon dioxide, methane, ethanol, isobutane, butane, propylene, propane, argon, hexafluoropropane, heptafluoropropane, hydrofluorocarbons (HFCs), hydrochlorofluorocarbons (HCFCs), chlorofluorocarbons (CFCs), hydrofluoroolefins (HFOs), chlorofluorocarbons, tetrafluoropropene, and difluoromethane. In other words, the gas sensor of this embodiment can be suitably used as a "refrigerant gas sensor" that detects refrigerant gases heavier than air.

[0034] The gas sensing element 22 is a semiconductor gas sensor including a platinum wire coil that functions as a heater and a metal oxide paste that coats the platinum wire coil in the form of beads. The metal oxide paste is preferably selected from a material that does not normally react in air but undergoes an oxidation-reduction reaction in the presence of the target gas. The metal oxide paste is made of metal oxides such as ZnO, SnO2, Fe2O3, WO3, and In2O3. The size of the gas sensing element 22 is approximately 0.09 mm to 10 mm.

[0035] The cap 20 protects the gas sensing element 22 from factors that may impair its function, such as rainwater and gases not to be detected. The cap 20 in this embodiment has a hollow cylindrical shape, but any internal shape is sufficient as long as it can take in a sufficient amount of gas to detect the target gas. The downward-facing end surface 23 of the cap 20 is housed in the container 10 so as to be spaced a predetermined distance IN from the opposing surface 13.

[0036] The cap 20 has at least a mesh portion (hereinafter also referred to as "opening") 21 in a portion thereof for introducing the target gas into the gas sensor 2. In this embodiment, the mesh portion 21 is provided near an end surface 23 of the cap 20. The mesh portion 21 is typically a metal net, and the number of meshes is, for example, 50 to 200. This allows surface tension to act on water on the surface of the mesh portion 21, preventing the water from penetrating into the cap 20. Note that the mesh portion 21 may be formed integrally with the cap 20 using a material such as resin, or may be a breathable material such as nonwoven fabric or sponge, as long as it can introduce the target gas.

[0037] The opening 21 is arranged so as not to overlap in the vertical direction with the gas inlet 17 and the drain outlet 18 provided on the opposing surface 13. This makes it difficult for water that has entered through the gas inlet 17 and the drain outlet 18 to enter the gas sensor 2.

[0038] The connection terminal 24 is configured to extend from the inside to the outside of the gas sensor 2 so as to electrically connect the gas sensing element 22 and the substrate 3. The connection terminal 24 is a metal pin member provided to protrude upward. The connection terminal 24 electrically connects the gas sensing element 22 and the electric circuit 31 by being pressed against, inserted into, or adhered to the substrate 3 located on the gas sensor 2.

[0039] The adsorption section 25 is provided to prevent a decrease in the catalytic activity of the gas sensing element 22 and functions as a "gas filter." The adsorption section 25 is made of powdered or beaded adsorption material, and can contain one or more materials selected from porous particles such as activated carbon, activated clay, silica, alumina, and zeolite. This can reduce the effects of ethyl alcohol, silicon gas, and the like present in the usage environment, improving the durability of the gas sensor.

[0040] Referring particularly to FIG. 3, a gap IN is formed between the end face 23 of the gas sensor and the opposing face 13, with a predetermined gap therebetween. The gap IN is preferably 2.0 mm or more, and more preferably 3.5 mm or more. If the gap IN is less than 2.0 mm, gas is less likely to enter the opening 21 of the gas sensor, and there is a risk that the supplied target gas may be exhausted without being detected. The larger the gap IN, the easier it is for air to flow into the gas opening. However, due to the size constraints of the container 10, the upper limit of the gap IN is approximately 10.0 mm. This allows the gas sensor module 1 to reliably detect the target gas despite its compact size.

[0041] Referring again to FIG. 3, the substrate 3 includes an electric circuit 31 capable of controlling the operation of the gas sensor 2, and a cable 32 for electrically connecting the electric circuit 31 to an external device.

[0042] The substrate 3 can be selected from various substrates depending on the application, such as a rigid substrate made of an insulating material, a ceramic substrate that is resistant to chemical corrosion, etc. From the viewpoint of ensuring strength, the substrate 3 in this embodiment is a rigid substrate 3.

[0043] The electric circuit 31 is formed on the front and / or rear surface of the substrate 3 and is an assembly of interconnected electric and electronic components. The electric circuit 31 can be patterned arbitrarily depending on the purpose, and is therefore indicated by dotted lines in Fig. 3. The elements that make up the electric circuit 31 include, for example, integrated circuits, capacitors, resistors, and electrical wiring, and have functions such as converting the detection result of the gas sensor 2 into an electric signal and supplying power to the gas sensor 2.

[0044] The cable 32 is typically a wire 32 and is a member for electrically connecting the electrical circuit 31 housed in the container 10 to an external device (not shown). The cable 32 may include one or more wires 32. From the viewpoint of waterproofing, the wires 32 are preferably covered with a non-conductive material. The cable 32 extends from any surface of the container 10, for example, the side surface 14, to the external device.

[0045] In this embodiment, the case where communication with an external device is performed via a wire, i.e., the cable 32, has been described, but it goes without saying that communication with an external device may also be performed via a wireless element. In this case, it is preferable that the wireless element is also covered by the waterproof molding 4 from the viewpoint of preventing it from getting wet with water.

[0046] 4, the gas sensor 2, the cable 32, and the substrate 3 are combined together to form an assembly 5. Fig. 4 is a front view showing the assembly 5 of this embodiment. In the assembly 5, the parts that require electrical current, such as the cable 32, the connection terminal 24, and the substrate 31, are exposed, and there is a risk of electrical leakage due to the adhesion of water.

[0047] Therefore, the assembly 5 of this embodiment is molded to cover the substrate 3 with a waterproof molded body 4 that is waterproof and non-conductive. The waterproof molded body 4 is molded to cover a portion of the substrate 3 and a portion of the gas sensor 2. The waterproof molded body 4 of this embodiment is preferably a hot melt adhesive, but can be selected from various materials that combine insulating and waterproofing properties, such as thermoplastic adhesives, polyethylene, acrylic resin, polypropylene, polycarbonate, epoxy resin, phenolic resin, polyurethane resin, silicone, urethane rubber, and fluororubber. Because hot melt adhesives are softer than other materials, they can easily adhere to waterproofed components such as the substrate 3. In other words, waterproofing can be improved. This ensures reliable waterproofing even for gas sensors that require an opening in the container despite being installed outdoors.

[0048] The waterproof molded body 4 is preferably made of a material that can be used as an injection molding material. The waterproof molded body 4 of this embodiment can be waterproofed in a desired area in a short time by simply inserting the assembly 5 and injection molding it. The "desired area" here refers to the area requiring electrical conduction, i.e., the area including the connection terminal 24 of the gas sensor 2, the electrical circuit 31, and the connection point between the cable 32 and the substrate 20. To enhance waterproofing, the desired area may also include the boundary areas of each component, i.e., the boundary between the cable 32 and the substrate 3 and the boundary between the gas sensor 2 and the substrate 3. It should be noted that the gas opening 21 of the gas sensor 2 must be exposed in order to allow the gas to be detected to enter. By forming the waterproof molded body 4 of this embodiment by injection molding, it is no longer necessary to ensure the waterproofing performance of each component, thereby reducing manufacturing costs.

[0049] The gas sensor module 1 of this embodiment is typically a "refrigerant gas sensor" that suitably detects refrigerant gas, and is installed in an environment where an air conditioner is installed, i.e., in an air conditioner or outdoor unit installed in a building or vehicle. When installed in an outdoor unit in particular, the sensor is subject to weather, so waterproofing must be applied at least to the locations where electrical connections are required. The gas sensor module 1 of this embodiment can be reliably waterproofed by tightly covering the electrical components such as the substrate 3 with the waterproof molded body 4, thereby improving water resistance.

[0050] (About the effects) Referring to FIG. 6, the flow path of the target gas within the gas sensor module 1 of this embodiment will be described. The target gas is supplied through the gas inlet 17 and then diffused into the internal space IS so as to be guided to the vent 19. The target gas diffused into the internal space IS is guided downward by the air exhausted from the drain outlet 18 and then guided to the opening 21 of the gas sensor 2 through the gap IN provided at a predetermined distance. In this way, the gas sensor module 1 of this embodiment can smoothly introduce the target gas into the gas sensor 2, even though the surface 13 facing the opening 21 of the gas sensor does not have an opening. In other words, the gas sensor module 1 can accurately detect the target gas while improving the waterproof performance of the gas sensor.

[0051] The gas sensor module of this embodiment is small in size, yet has a smooth air flow path in the internal space IS, allowing the module to be installed at a more flexible location and to instantly detect the target gas. Note that "free installation location" here means that the module can be installed anywhere below the area where gas leakage is possible.

[0052] (Production method) Next, a method for manufacturing the gas sensor module according to this embodiment will be described with reference to Fig. 7. Fig. 7 is a flowchart for explaining the method for manufacturing the gas sensor module according to this embodiment.

[0053] First, a container having an internal space formed by multiple surfaces, a gas sensor having an opening for taking in a gas to be detected, and a substrate having an electric circuit electrically connected to the gas sensor are prepared (preparation step S1).

[0054] At least two openings, i.e., a gas inlet for introducing the target gas into the internal space and a drain outlet for draining water entering the internal space, are formed in the container prepared in the preparation step S1 (opening forming step S2). In this embodiment, the gas inlet and the drain outlet are provided on the same surface.

[0055] Next, an assembly including the gas sensor and the substrate prepared in the preparation step S1 is formed (assembly formation step S3). From the viewpoint of facilitating the next step, it is preferable that the assembly is assembled so that the opening of the gas sensor faces in substantially the same direction as the extending direction of the substrate (downward in this embodiment).

[0056] The assembly assembled in the assembly forming step S3 is hot melt molded to cover at least the parts that require electrical continuity, such as the electrical circuits (waterproofing step S4). Here, since the opening of the gas sensor faces downward, molding can be easily performed from the front-to-back or left-to-right directions. This forms a waterproof molded body.

[0057] The assembly that has been subjected to the waterproofing step S4 is housed in the container formed in the opening forming step S2 (housing step S5). In the housing step S5, the opening of the gas sensor faces one surface of the container, and the opening and the gas inlet of the container are not opposite each other. The gas sensor module 1 manufactured in this embodiment has a structure that makes it difficult for water to adhere to the opening 21 of the gas sensor, so that it is possible to improve waterproof performance despite a simple structure.

[0058] Here, as an additional manufacturing method, a step of floating and fixing the assembly in the container may be further provided (fixing step S6). Fixing step S6 may be performed before or after opening forming step S2, or before or after accommodation step S5. Fixing step S6 ensures a constant distance between gas opening 21 and the bottom surface of the container, ensuring reliable gas intake. Various methods can be used as fixing means, for example, engaging members such as ribs, or fixing members such as screws.

[0059] In this embodiment, the gas sensor 2 is installed below the target gas to be detected inside the device and takes in the target gas from below, so the target gas is a "gas heavier than air." However, if the gas sensor 2 is installed above the target gas to be detected inside the device and takes in the target gas rising from below, the target gas may be a "gas lighter than air." Examples of gases lighter than air include hydrogen, helium, and nitric oxide. Even in this case, the gas inlet can be appropriately positioned to allow the target gas to be easily taken in.

[0060] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0061] 1 gas sensor module, 2 gas sensor, 3 substrate, 4 waterproof molded body, 5 assembly, 10 container, 11 storage section, 12 front surface, 13 bottom surface (opposing surface), 14 side surface, 15 top surface, 16 rear surface, 17 gas inlet, 18 drain port, 19 ventilation hole, 20 cap, 21 opening (mesh section), 22 gas sensing element, 23 end surface, 24 connection terminal, 25 suction section, 31 electrical circuit, 32 cable, IS internal space, IN gap.

Claims

1. a container formed with multiple surfaces and having an interior space; a gas sensor having an opening for taking in a gas to be detected; a substrate having an electrical circuit electrically connected to the gas sensor; a waterproof molding that covers the gas sensor and at least a part of the substrate, The container comprises: The gas sensor and the substrate are accommodated in the internal space; a gas inlet for introducing the detection target gas into the internal space; a drain outlet for draining water that enters the internal space, The gas sensor module is arranged such that an opening of the gas sensor faces one surface of the container, and the opening and the gas inlet of the container do not face each other.

2. an opposing surface of the container that faces the opening is located below the opening of the gas sensor; 2. The gas sensor module according to claim 1, wherein the gas inlet is provided on the opposing surface.

3. 2. The gas sensor module according to claim 1, wherein the gas to be detected is a gas heavier than air.

4. 2. The gas sensor module according to claim 1, wherein a gap of 2.0 mm or more is provided between the opening of the gas sensor and the opposing surface.

5. the container further includes a vent for introducing the target gas into the internal space; The opening area of ​​the vent hole is 0.5 mm ２ 4mm or more ２ 2. The gas sensor module according to claim 1, wherein:

6. The opening area of ​​the gas inlet is 3 mm ２ 30mm or more ２ 2. The gas sensor module according to claim 1, wherein:

7. The drain outlet is provided on the opposing surface of the container, The opening area of ​​the drain hole is 1.5 mm ２ Over 4.0 mm ２ 3. The gas sensor module according to claim 2, wherein:

8. preparing a container having an internal space formed by a plurality of surfaces, a gas sensor having an opening for introducing a detection target gas, and a substrate having an electric circuit electrically connected to the gas sensor; forming a gas inlet through which the detection target gas is introduced into the internal space and a drain outlet through which water entering the internal space is drained in the container; forming an assembly including the gas sensor and the substrate; forming a waterproof molding by hot melt molding so as to cover a desired area of ​​the assembly; and placing the assembly covered with the waterproof molding in the container, In the housing step, the opening of the gas sensor and one surface of the container are arranged so as not to face each other, and the opening and the gas inlet of the container are arranged so as not to face each other.

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