Gas sensor module

Abstract

[Problem] To provide a gas sensor module capable of securing high waterproofness between a housing and a lid. [Solution] The gas sensor module comprises a gas sensor, the housing, the lid, and a seal member. The gas sensor detects a gas to be detected. The housing has a top wall and a first sidewall, accommodates the gas sensor in an accommodation space formed by the top wall and the first sidewall, and takes the gas to be detected into the accommodation space. The lid covers a first end surface, which is an end surface of the first sidewall on the opposite side from the top wall. The seal member is provided over the entire circumference of the lid, and includes a resin material different from the housing and the lid.

Description

Gas sensor module

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[0001] The present invention relates to a gas sensor module.

[0002] Patent Document 1 (Japanese Patent Application Laid-Open No. 2024-170789) discloses a substrate having an electric circuit connected to a gas sensor, a waterproof molded body that covers a part of the substrate including the electric circuit and a part of the gas sensor to waterproof the covered part, a container that houses the gas sensor and the substrate in an internal space, a gas sensor that detects a gas, a substrate having an electric circuit connected to the gas sensor, and a container that houses the gas sensor and the substrate in an internal space. The container is composed of a housing part and a lid part.

[0003] Japanese Patent Application Laid-Open No. 2024-170789

[0004] Among the components housed in the housing part of the gas sensor module of Patent Document 1, only the component covered with the waterproof molded body has a waterproof function. However, if the substrate or the like is covered with the waterproof molded body, it becomes difficult to check their states later. Therefore, it has been desired to ensure waterproof performance while facilitating the inspection inside the module.

[0005] An object of the present invention is to provide a gas sensor module that can ensure high waterproof performance between a housing and a lid.

[0006] Hereinafter, a plurality of aspects as means for solving the problems will be described. These aspects can be arbitrarily combined as necessary.

[0007] A gas sensor module according to an aspect of the present invention includes a gas sensor, a housing, a lid, and a seal member. The gas sensor detects a gas to be detected. The housing has a top wall and a first side wall, houses the gas sensor in an accommodation space formed by the top wall and the first side wall, and takes in the gas to be detected into the accommodation space. The lid covers a first end face which is an end face on the opposite side of the top wall of the first side wall. The seal member is provided over the entire circumference of the lid and contains a resin material different from that of the housing and the lid.

[0008] Preferably, the first side wall includes an outer peripheral surface facing the outside and an inner peripheral surface facing the housing space. The housing further includes a second side wall surrounding the outer periphery of the outer peripheral surface and provided to accommodate a sealing member, and a sealing member housing groove including the outer peripheral surface and the second side wall.

[0009] Preferably, the lid includes a first surface facing the containment space, a second surface facing the outside of the containment space, and a side surface connecting the first and second surfaces. The sealing member covers the peripheral edge of the first surface, at least the peripheral edge of the second surface, the side surface, and at least the edge of the outer peripheral side surface on the first end surface side.

[0010] Preferably, the side surface of the lid is located outward from the outer peripheral surface of the first side wall.

[0011] Preferably, the second end face of the second side wall, which is the end face opposite to the top wall, is further from the top wall than the first end face of the first side wall.

[0012] Preferably, one end of the second side wall is connected to the outer peripheral surface of the first side wall.

[0013] Preferably, the lid has a stepped portion on its second surface. The sealing member further covers the stepped portion.

[0014] Preferably, the housing further comprises a fixing portion extending along a second side wall. The fixing portion has a contact surface that is parallel to the second surface of the lid and is located further from the top wall than the second surface of the lid.

[0015] Preferably, the lid has an engaging portion on its first surface that can engage with the housing. The first side wall has an engaged portion that can engage with the engaging portion.

[0016] Preferably, the sealing member contains a hot-melt resin.

[0017] According to the gas sensor module of the present invention, high waterproofness of the housing and lid is ensured.

[0018] This is an exploded perspective view of the gas sensor module. This is a bottom perspective view of the gas sensor module. This is an enlarged front cross-sectional view of the gas sensor module. This is a bottom perspective view of the cover 40.

[0019] Embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and their descriptions will not be repeated.

[0020] <Embodiment> (1) Configuration The overall configuration of the gas sensor module 1 according to this embodiment will be described with reference to Figure 1. The gas sensor module 1 mainly comprises a gas sensor 10, an electronic circuit 20, a housing 30, a lid 40, and a sealing member 50. The directions up and down, as well as the height direction h, depth direction d, and width direction w used in the following description, correspond to the directions indicated by arrows in the figure. Furthermore, the directions up and down used in the following description are used for the convenience of explanation and do not limit the orientation of the gas sensor module 1 during use.

[0021] (1-1) Gas Sensor 10 The gas sensor 10 has a gas-sensing element (not shown) that detects the gas to be detected (hereinafter also simply referred to as "gas") and a cap 11 that covers the gas-sensing element. The gas sensor 10 is connected to the electronic circuit 20 via a connection terminal (not shown) provided on its lower surface.

[0022] The cap 11 protects the gas-sensing element from factors that interfere with it, such as gases that are not the target of detection. In this embodiment, the cap 11 is cylindrical and made of metal or resin, but its material and shape are not limited as long as it has an internal shape that can take in a sufficient amount of gas to detect the target gas.

[0023] Furthermore, the cap 11 has a gas inlet 11a in at least a portion of it for drawing the gas to be detected into the gas sensor 10. The gas inlet 11a may be covered with, for example, a metal mesh to prevent foreign matter from entering. In this embodiment, the gas inlet 11a is covered with a filter 37a, which will be described later.

[0024] The gas sensing element of this embodiment is a catalytic combustion type gas sensor that includes a platinum wire that performs a heating function and a catalyst layer that covers the platinum wire. The catalyst layer is an electrodeposited material obtained by electrolysis of a metal such as platinum. The gas sensing element detects the gas by a change in resistance value that occurs when the gas to be detected comes into contact with its surface, causing a catalytic reaction. The size of the gas sensing element is, for example, about 0.09 mm to 10 mm.

[0025] The gas sensor module 1 of this embodiment has two gas sensors 10. One of these may be used for detecting the target gas, and the other for detecting (compensating for) changes in ambient temperature. The compensating gas sensor does not have catalytic activity to burn the target gas and is used to compensate for changes in resistance caused by changes in ambient temperature. This makes it possible to detect hydrogen gas more reliably.

[0026] Furthermore, although the gas sensor 10 in this embodiment has been described as a catalytic combustion type gas sensor, its type is not particularly limited. For example, various gas sensors such as semiconductor type gas sensors and electrochemical type gas sensors can be used. Also, although the gas sensor module 1 in this embodiment has two gas sensors 10, one sensor may suffice as long as it can detect the target gas.

[0027] The gas sensor 10 detects the target gas and outputs the detection result as an electrical signal to the outside. Hydrogen can be particularly suitably detected as the target gas, but various other gases such as methane, propane, carbon dioxide, nitric oxide, argon gas, and fluorocarbon gases can also be detected.

[0028] (1-2) Electronic circuit 20 The electronic circuit 20 is electrically connected to the gas sensor 10 and can, for example, detect changes in the electrical resistance of a gas sensing element and output the detection result to the outside as an electrical signal. The electronic circuit 20 includes a substrate 21, one or more electronic components 22, and an output terminal 23.

[0029] The substrate 21 can be selected from various substrates depending on the application, such as a rigid substrate formed of an insulating material or a ceramic substrate that is resistant to chemical corrosion. From the viewpoint of ensuring strength, the substrate 21 in this embodiment is a rigid substrate 3.

[0030] One or more electronic components 22 and output terminals 23 are mounted on the top and / or bottom surfaces of the substrate 21. One or more electronic components 22 may have an electrical circuit, and any circuit pattern is possible depending on the purpose. The elements constituting the electronic component 22 are, for example, integrated circuits, capacitors, resistors, electrical wiring, etc., and have functions such as converting the detection result of the gas sensor 10 into an electrical signal and supplying power to the gas sensor 2. One end of the output terminal 23 is connected to the substrate 21, and the other end penetrates the housing 30 and is exposed to the outside. By connecting a cable (not shown) to the other end of the output terminal 23, the electronic circuit 20 housed in the housing 30 can be electrically connected to an external device (not shown).

[0031] In this embodiment, the case where communication with an external device is performed via a wired connection, i.e., via the output terminal 23, has been described. However, communication with an external device may also be performed wirelessly, i.e., via a wireless element instead of the output terminal 23.

[0032] (1-3) Housing 30 The housing 30 has a housing space S capable of accommodating the gas sensor 10 and the electronic circuit 20. The housing 30 mainly has a top wall 31, a first side wall 32, a second side wall 33, a sealing member housing groove 34, two fixing parts 35, a connector 36, and a gas introduction part 37.

[0033] The housing 30 is formed from, for example, resin, ceramic, or a composite material in which a filler is mixed into the resin. The resin can be selected from a variety of materials, such as thermoplastic resin, polypropylene, ABS, polyethylene terephthalate, polycarbonate, PBT (polybutylene terephthalate), polyamide, PE (polyethylene), POM (polyoxymethylene), acrylic, and Teflon (registered trademark). It is preferable that the housing 30 be formed from a thermoplastic resin. This allows it to be manufactured quickly and easily by injection molding.

[0034] The top wall 31 in this embodiment is a plate-like member with a substantially rectangular shape. The top wall 31 is provided with a gas introduction section 37 at a position facing the gas inlet 11a of the gas sensor 10. The shape of the gas introduction section 37 is not particularly limited as long as it can take in the gas to be detected into the containment space S, and may be a cylindrical shape protruding upward from the top wall 31, or it may be an opening provided on substantially the same plane as the top wall 31. The gas introduction section 37 includes a filter 37a that allows the gas to be detected to pass through while making it difficult for miscellaneous gases, which are gases not to be detected, to pass through. The filter 37a is welded to the inner surface and ribs 37b of the gas introduction section 37. The gas introduction section 37 also further includes three intersecting ribs 37b.

[0035] The first side wall 32 is a surface that extends downward from the outer circumference of the top wall 31. Of the first side wall 32, the first end surface 32a, which is the end surface opposite to the top wall 31 (in other words, the lower end surface), is the opening o of the housing 30. The accommodation space S is the space formed by the top wall 31 and the first side wall 32. Of the first side wall 32, the surface facing this accommodation space S is the inner circumferential surface 32c, and the surface that does not face the accommodation space S (faces the outside) is the outer circumferential surface 32b.

[0036] The inner circumferential surface 32c has an engaged portion 32d having a concave or convex shape that can engage with the engaging portion 45 (described later) of the lid 40. In this embodiment, because the engaged portion 32d is located on the inner circumferential surface 32c, the number of protrusions and recesses on the outer circumferential surface 32b can be reduced, resulting in a cleaner appearance. In other words, the gas sensor module 1 of this embodiment can have improved appearance and design.

[0037] The second side wall 33 surrounds the outer periphery of the outer periphery surface 32b, and is provided in a substantially L-shape in cross-section by connecting one end to the outer periphery surface 32b of the first side wall 32. The second side wall 33 has a first portion 33a, one end of which is connected to the outer periphery surface 32b and the other end extending outward (in the width direction w or depth direction d) by a predetermined width, and a second portion 33b extending from the other end of the first portion 33a toward the opening o (in the height direction h).

[0038] The first portion 33a is preferably located approximately in the center of the first side wall 32 in the height direction h. However, it is not limited to this as long as waterproofing can be maintained, and the first portion 33a may be located at a height of 1 / 3 of the height of the first side wall 32 from the opening o side, or at a height of 1 / 4 of the height. The second portion 33b extends downward from the first side wall 32. That is, the second end face 33c of the second side wall 33 is located below the first end face 32a of the first side wall 32. This ensures that the first end face 32a is reliably covered by the sealing member 50. Furthermore, it is preferable that the second end face 33c and the second surface 42 of the lid 40, which will be described later, are located at approximately the same height. By making the second end face 33c and the second surface 42 the ends, the depth of the sealing member receiving groove 34 can be increased. It is preferable that the first portion 33a and the second portion 33b have one or more irregular shapes on their inner surfaces from the viewpoint of increasing the surface area and lengthening the water intrusion path.

[0039] The seal member housing groove 34 is formed by the outer peripheral surface 32b of the first side wall 32 and the second side wall 33, and houses the seal member 50. Referring particularly to Figure 3, it is preferable that the height H1 from the first end face 32a to the first portion 33a is at least one-quarter of the height of the first side wall 32. Also, it is preferable that the height H2 from the first end face 32a to the second end face 33c is greater than the height from the first surface 41 to the second surface 42 of the lid 40. This increases the surface area of ​​the seal member housing groove 34, preventing water from entering from the boundary between the housing 30 and the lid 40.

[0040] Referring again to Figure 1, the fixing portion 35 is used to fix the gas sensor module 1 to the mounting target member. The mounting target member here refers to equipment that uses or stores the gas to be detected, and the gas sensor module 1 is fixed in the vicinity of or inside such equipment. The lower surface of the gas sensor module 1 is fixed facing the surface of the mounting target member.

[0041] The fixing portion 35 is a ring-shaped member in plan view that is provided to protrude outward from the second side wall 33. The fixing portion 35 has a ring-shaped mounting hole 35a into which a fixing member such as a bolt or screw can be inserted. The lower surface of the fixing portion 35 has a contact surface 35b that is parallel to the second end surface 33c and the second surface 42 (described later) of the lid 40. The contact surface 35b corresponds to the lowest surface of the gas sensor module 1. That is, the contact surface 35b is located below the second end surface 33c and the second surface 42 of the lid 40. This ensures a gap between the lid 40 and the member to be attached, thereby improving heat dissipation in the housing space S and preventing moisture from accumulating between the lid 40 and the member to be attached.

[0042] The connector 36 securely connects the output terminal 23 to a cable (not shown) for electrical connection. To facilitate cable storage, the connector 36 in this embodiment is cylindrical. One end of the output terminal 23 is located inside the connector 36, while the other end penetrates the first side wall 32 and the second side wall 33 and is connected to the electronic circuit 20 housed inside the housing space S.

[0043] Furthermore, the housing 30 in this embodiment may have a substrate engagement portion (not shown) that can sandwich an O-ring (not shown) between the outer circumference of the upper surface of the substrate 21 and the inner circumferential side surface 32c of the housing. This makes it possible to maintain airtightness on the side of the housing space S of the housing 30 that is above the substrate 21 (gas sensor 10). In other words, even if foreign matter gets into the side below the substrate 21 (lid), it is possible to prevent the foreign matter from entering the gas sensor 10 side.

[0044] Since the housing 30 of the present embodiment includes the second side wall 33, the waterproof performance can be enhanced. Specifically, water that infiltrates from the second end face needs to pass through the second portion 33b that extends above the first end face 32a, the first portion 33a, and the outer peripheral side face 32b. Thus, by providing the water intrusion path to be long in a way that it winds in the vertical direction, even if water has intruded, it can be stopped midway.

[0045] (1 - 4) Lid 40 The lid 40 covers the opening o on the lower surface of the housing 30, that is, the first end face 32a of the first side wall 32. The lid 40 includes a first face 41 facing the accommodation space S, a second face 42 facing the outside of the accommodation space S, and a side face 43 connecting between the first face 41 and the second face 42.

[0046] Similar to the housing 30, the lid 40 is formed of, for example, resin, ceramic, or a composite material in which a filler is mixed into resin. The resin can be selected from various materials such as, for example, thermoplastic resin, polypropylene, ABS, polyethylene terephthalate, polycarbonate, PBT (polybutylene terephthalate), polyamide, PE (polyethylene), POM (polyoxymethylene), Teflon (registered trademark), etc. Note that the material of the housing 30 and the material of the lid 40 may be the same or different.

[0047] Referring particularly to FIG. 3, the first face 41 abuts against the first end face 32a when the lid 40 covers the opening o. Thereby, it is possible to suppress the seal member 50 accommodated in the seal member accommodation groove 34 from flowing into the accommodation space S. Further, the lid 40 of the present embodiment has an engaging portion 45 on the first face 41 that can engage with the engaged portion 32d of the housing 30.

[0048] The engaging portion 45 has a support portion 45a extending upward from the first surface 41 of the lid 40, and a claw portion 45b provided at the tip of the support portion 45a and protruding in the width direction w or the depth direction d. The claw portion 45b is provided at a position where it engages with the engaged portion 32d when the lid 40 covers the opening o. Although the lid 40 of the present embodiment is illustrated as having two engaging portions 45 per side, the engaging portion 45 only needs to be fixed so that the lid 40 does not come off, and the number thereof is not limited to this. Further, since the claw portion 45b engages with the inner peripheral side surface 32c of the housing, the appearance design of the gas sensor module 1 can be made neater.

[0049] The lid 40 of the present embodiment is sealed with the seal member 50 while being engaged by the engaging portion 45. Thus, by fixing the lid 40 to the housing with two types of structures, the fixing strength of the lid can be further increased. Also, even if the temperature in the accommodation space S rises due to the driving of the gas sensor 10, it is possible to prevent the lid 40 from lifting up.

[0050] The second surface 42 of the lid 40 corresponds to the lower surface of the gas sensor module 1. The lid 40 of the present embodiment has a stepped portion 44 on the second surface. The stepped portion 44 is provided in a tapered shape on the upper side from the reference surface of the second surface 42. On the second surface 42, the surface located above the reference surface and covered by the seal member 50 is defined as the outer peripheral region a. The reference surface of the second surface 42 is preferably located below the first end surface 32a of the housing 30 and substantially at the same height as the second end surface 33c. Because the stepped portion 44 is tapered, the water intrusion path from the second surface side can be lengthened, and the waterproof effect can be further enhanced.

[0051] Because the lid 40 of the present embodiment includes the stepped portion 44, the waterproof performance can be enhanced. Specifically, the water that infiltrates from the second surface needs to pass through the stepped portion 44, the outer peripheral region a, the side surface 43, and the outer periphery of the first surface 41. By providing the water intrusion path in a labyrinth shape like this, even if water has invaded, it can be stopped midway.

[0052] As shown in Figure 3, the side surface 43 is located outside the outer peripheral side surface 32b of the housing 30 (in other words, it is positioned to protrude in the width direction from the housing 30). This allows for a more complex shape for the seal member housing groove 34, and a longer water intrusion path.

[0053] (1-5) Sealing Member 50 Next, with reference to Figure 2, the sealing member 50 that covers the outer circumference of the lower surface of the gas sensor module 1 will be described. The sealing member 50 seals the entire boundary between the housing 30 and the lid 40. In this embodiment, the sealing member 50 is provided by filling the sealing member housing groove 34 with hot melt resin. That is, the sealing member 50 covers at least the entirety of the sealing member housing groove 34.

[0054] From the viewpoint of improving aesthetics, it is preferable that the sealing member 50 is provided such that its lower surface is substantially flush with the second end surface 33c of the housing 30 and the second surface 42 of the lid 40. This results in a clean appearance for the lower surface of the gas sensor module 1 and facilitates the installation of the gas sensor module 1.

[0055] The sealing member 50 contains a different type of resin material than the housing 30 and the lid 40. The sealing member 50 can be selected from various waterproof materials, such as thermoplastic resin, polyethylene, acrylic resin, polypropylene, polycarbonate, polyurethane, silicone, urethane rubber, and fluororubber. It is preferable that the sealing member 50 is made of a softer material than the housing 30 or the lid 40. This improves the adhesion in the sealing member housing groove 34 and enhances the waterproof performance. In this embodiment, the sealing member 50 is made of thermoplastic resin, but the material is not particularly limited. In the case of thermoplastic resin, the sealing member can be filled by injection molding, allowing it to be molded in a desired area in a short time.

[0056] According to the sealing member 50 of this embodiment, since it is provided to seal the labyrinth-shaped sealing member housing groove 34, the airtightness (waterproof and dustproof performance) of the housing space S of the gas sensor module 1 can be improved more reliably. Because the entire housing space S is waterproofed and foreign matter contamination can be prevented, inspection of the gas sensor module 1 can be easily performed simply by opening the lid, even though the electronic circuit 20 itself is not covered with a waterproof and dustproof structure such as resin.

[0057] <Conclusion> Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the spirit of the invention. In particular, the multiple embodiments and modifications described herein can be arbitrarily combined as needed.

[0058] 1: Gas sensor module 10: Gas sensor 11: Sensor case 11a: Gas inlet 20: Electronic circuit 21: Circuit board 22: Electronic component 23: Output terminal 30: Housing 31: Top wall 32: First side wall 32a: First end face 32b: Outer peripheral side 32c: Inner peripheral side 32d: Engaged part 33: Second side wall 33a: First part 33b: Second part 33c: Second end face 34: Seal member housing groove 35: Fixing part 35a: Mounting hole 35b: Contact surface 36: Connector 37: Gas inlet 37a: Filter 37b: Rib 40: Cover 41: First surface 42: Second surface 43: Side 44 : Step portion 45 : Engaging portion 45a : Support portion 45b : Claw portion 50 : Seal member a : Outer peripheral region A : Surface d : Depth direction H1 : Depth H2 : Distance h : Height direction o : Opening S : Accommodation space w : Width direction

Claims

1. A gas sensor module comprising: a gas sensor for detecting a target gas; a housing having a top wall and a first side wall, housing the gas sensor in a containment space formed by the top wall and the first side wall, and drawing the gas into the containment space; a lid covering a first end face which is the end face of the first side wall opposite to the top wall; and a sealing member provided around the entire circumference of the lid, comprising a resin material different from that of the housing and the lid.

2. The gas sensor module according to claim 1, wherein the first side wall includes an outer peripheral surface facing the outside and an inner peripheral surface facing the housing space, and the housing further includes a second side wall surrounding the outer periphery of the outer peripheral surface and provided capable of housing the sealing member, and a sealing member housing groove including the outer peripheral surface and the second side wall.

3. The gas sensor module according to claim 2, wherein the lid includes a first surface facing the containment space, a second surface facing the outside of the containment space, and a side surface connecting the first surface and the second surface, and the sealing member covers the peripheral edge of the first surface, at least the peripheral edge of the second surface, the side surface, and at least the edge of the outer peripheral side surface on the first end surface side.

4. The gas sensor module according to claim 3, wherein the side surface of the lid is located outward from the outer peripheral side surface of the first side wall.

5. The gas sensor module according to claim 3, wherein the second end face of the second side wall, which is the end face opposite to the top wall, is further away from the top wall than the first end face of the first side wall.

6. The gas sensor module according to claim 2, wherein one end of the second side wall is connected to the outer peripheral surface of the first side wall.

7. The gas sensor module according to claim 3, wherein the lid has a stepped portion on the second surface, and the sealing member further covers the stepped portion.

8. The gas sensor module according to claim 3, wherein the housing further comprises a fixing portion extending from the second side wall, the fixing portion having a contact surface parallel to the second surface of the lid and located further from the top wall than the second surface of the lid.

9. The gas sensor module according to claim 1, wherein the lid has an engaging portion on its first surface that can engage with the housing, and the first side wall has an engaged portion that can engage with the engaging portion.

10. The gas sensor module according to any one of claims 1 to 9, wherein the sealing member comprises a hot melt resin.

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