A humidity sensor

Abstract

The utility model provides a kind of humidity sensor, comprising: sensor shell, circuit board is installed in sensor shell, and detection element is provided on circuit board;Cover plate assembly, cover plate assembly includes: cover plate body, air inlet is opened on cover plate body;Enclosure, enclosure is set to the side of cover plate body towards circuit board, and it is arranged around the air inlet, and enclosure and circuit board surface are enclosed to form measuring cavity, and detection element is located in measuring cavity.The utility model realizes the structural integration and modularization of humidity sensor by integrating design of measuring cavity, breathable membrane and cover plate body, significantly reduces the number of parts, simplifies assembly process, reduces production cost, while the enclosure of measuring cavity and cover plate body adopt integrated forming process, eliminate the joint hidden danger in traditional split structure, greatly improve the sealing reliability of measuring cavity.

Description

Technical Field

[0001] This utility model belongs to the field of gas detection technology, and specifically relates to a humidity sensor. Background Technology

[0002] Currently, humidity sensors generally adopt a split-type structure design, where the measuring chamber and the breathable membrane are independent components that require additional assembly processes to install onto the sensor housing. This design results in a large number of parts, complex assembly procedures, and insufficient sealing at the joint between the measuring chamber and the housing. This makes the internal circuitry of the sensor susceptible to moisture intrusion, necessitating additional protective measures such as conformal coatings or protective adhesives. This not only increases production costs and process difficulty but also affects product reliability. Therefore, in automotive intake systems, especially engine intake systems—a typical high-reliability application scenario—the problems of poor sealing, complex processes, high costs, and low reliability caused by the structural design flaws of existing split-type humidity sensors are significantly amplified. Utility Model Content

[0003] In view of the shortcomings of the prior art, the purpose of this utility model is to provide a humidity sensor to solve the problems of a large number of parts, complex assembly process, insufficient sealing at the joint between the measuring cavity and the housing, and increased production cost, process difficulty and reduced product reliability caused by the use of a split structure design for the detection element.

[0004] To achieve the above and other related objectives, this utility model proposes a humidity sensor, comprising:

[0005] A sensor housing, wherein a circuit board is installed inside the sensor housing, and a detection element is provided on the circuit board;

[0006] Cover plate assembly, the cover plate assembly comprising:

[0007] The cover plate body has an air inlet.

[0008] The measuring cavity wall is disposed on the side of the cover plate body facing the circuit board and arranged around the air inlet. The measuring cavity is formed by the measuring cavity and the surface of the circuit board, and the detection element is located inside the measuring cavity.

[0009] In one embodiment of the present invention, the frame extends toward the circuit board, and the frame and the cover plate body are an integral structure.

[0010] In one embodiment of the present invention, the frame portion is embedded in the cover plate body and is sealed to the cover plate body.

[0011] In one embodiment of the present invention, the frame and the circuit board are sealed together along the circumference of the measuring cavity to seal and isolate the chamber of the sensor housing and the measuring cavity.

[0012] In one embodiment of this utility model, the surfaces of the circuit board in the frame are filled with sealant to achieve a sealed connection.

[0013] In one embodiment of the present invention, a breathable membrane is further included, which is disposed on the side of the cover plate body opposite to the circuit board and covers the air inlet.

[0014] In one embodiment of this utility model, the breathable membrane and the cover plate body are fixedly connected by ultrasonic welding or adhesive.

[0015] In one embodiment of the present invention, a positioning guide groove is formed on the side of the cover plate body opposite to the circuit board. The positioning guide groove is arranged around the air inlet and is used to position and guide the breathable membrane.

[0016] In one embodiment of the present invention, the size of the positioning guide groove gradually increases toward the side facing away from the circuit board to form a sloping sidewall.

[0017] In one embodiment of the present invention, a drainage slope is provided on the side of the cover plate body away from the circuit board. The drainage slope extends from the bottom of the positioning guide groove toward the surface of the cover plate body in a direction away from the air inlet.

[0018] In one embodiment of this utility model, the angle between the drainage slope and the surface of the cover plate body is smaller than the angle between the sidewall of the positioning guide groove and the surface of the cover plate body in the direction radially outward from the air inlet.

[0019] In one embodiment of the present invention, a welding rib is provided around the bottom of the positioning guide groove around the air inlet, and the breathable membrane is welded and fixed to the cover plate body through the welding rib.

[0020] This utility model proposes a humidity sensor. The overall design not only reduces the amount of adhesive applied and assembly steps in traditional processes, but also enhances structural rigidity and environmental adaptability, achieving comprehensive optimization of the sensor in terms of sealing, durability, manufacturing efficiency, and cost control. It has the following beneficial effects:

[0021] This invention integrates the measuring chamber, the breathable membrane, and the cover plate body into a single design, achieving a unified and modular structure for the humidity sensor. This significantly reduces the number of parts, simplifies the assembly process, and lowers production costs.

[0022] This invention eliminates the seam hazards in traditional split structures by using an integrated molding process for the frame and cover plate, greatly improving the sealing reliability of the measuring cavity, effectively preventing moisture, dust and other pollutants from entering the sensor, protecting the circuit board from environmental damage, thereby reducing the reliance on additional protective measures and improving the long-term operational reliability of the product in harsh environments such as high humidity and dust.

[0023] In this utility model, the outer surface of the cover plate is provided with a positioning guide groove with a sloping sidewall and a drainage slope, which respectively realizes the self-centering guidance during the installation of the breathable membrane and the rapid drainage of liquid water on the surface, thereby improving the assembly efficiency and ensuring the stable air permeability of the air inlet area. Attached Figure Description

[0024] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. It is obvious that the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0025] Figure 1 This is a schematic diagram of the detection element in one embodiment of the present invention.

[0026] Figure 2 This is a partial cross-sectional schematic diagram of the detection element in one embodiment of the present invention.

[0027] Figure 3 This is an enlarged schematic diagram of the air inlet of the detection element in one embodiment of the present invention.

[0028] Label Explanation:

[0029] 10. Sensor housing; 20. Cover plate assembly; 30. Circuit board; 31. Detection element; 21. Cover plate body; 211. Air inlet; 212. Positioning guide groove; 213. Drainage slope; 214. Welding rib; 22. Breathable membrane; 23. Frame; 231. Measuring chamber; 232. Sealant. Detailed Implementation

[0030] The following specific examples illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. This utility model can also be implemented or applied through other different specific embodiments. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this utility model. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0031] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. The drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0032] In the following description, numerous details are explored to provide a more thorough explanation of embodiments of the present invention. However, it will be apparent to those skilled in the art that embodiments of the present invention may be practiced without these specific details. In other embodiments, well-known structures and devices are shown in block diagram form rather than in detail to avoid obscuring embodiments of the present invention.

[0033] Please see Figures 1 to 3 As shown, this utility model provides a humidity sensor designed to address the problems of numerous parts, complex assembly, poor sealing, and susceptibility to moisture intrusion in existing split-type structures. This is particularly relevant in high-reliability applications such as automotive intake systems, including engine intake systems, where structural design flaws lead to poor sealing, complex manufacturing processes, high costs, and low reliability. This sensor integrates the measuring chamber, breathable membrane, and cover plate into a unified structure, improving sealing reliability, reducing reliance on external protection, and lowering production costs.

[0034] Please see Figure 1 and Figure 2 As shown, in this embodiment, the humidity sensor includes a sensor housing 10 and a cover assembly 20. A circuit board 30 is installed inside the sensor housing 10, and a detection element 31 is integrated on the circuit board 30. The cover assembly 20 is sealed to the top opening of the sensor housing 10, preferably using laser welding, ultrasonic welding, or sealant bonding to achieve an airtight connection, ensuring effective isolation between the external environment and the interior of the housing.

[0035] Please see Figure 1 and Figure 2As shown, in this embodiment, the cover plate assembly 20 includes a cover plate body 21, a breathable membrane 22, and a surrounding frame 23. The cover plate body 21 is the structural foundation of the entire cover plate assembly, and the breathable membrane 22 and the surrounding frame 23 are disposed on the cover plate body 21. The cover plate body 21 is made of temperature-resistant and corrosion-resistant engineering plastic or metal material, and can be formed by injection molding, die casting, or machining. An air inlet 211 is provided on the cover plate body 21 to guide the gas to be measured into the sensor. The breathable membrane 22 is disposed on the side of the cover plate body 21 away from the circuit board 30 (i.e., the outer surface) and completely covers the air inlet 211. In this embodiment, the breathable membrane 22 is made of a hydrophobic microporous material, such as polytetrafluoroethylene, expanded polytetrafluoroethylene, or polyvinylidene fluoride, which allows gas molecules to pass through but effectively blocks liquid or particulate contaminants such as moisture, dust, and oil mist from entering the sensor. The measuring wall 23 is located on the inner surface of the cover plate body 21 facing the circuit board 30. It extends downward around the air inlet 211 in a ring or cylindrical structure to form a gas flow space. The frame 23 and the surface of the circuit board 30 enclose the measuring cavity 231. The detection element 31 is located in the measuring cavity 231. The measuring cavity 231 is connected to the air inlet 211, so that the external gas is filtered by the breathable membrane 22 and enters the measuring cavity 231 through the air inlet 211, and comes into contact with the detection element 31 located therein to complete the humidity detection.

[0036] Please see Figure 1 and Figure 2 As shown, in this embodiment, the frame 23 is disposed on the side of the cover plate body 21 facing the circuit board 30 and extends along the side facing the circuit board 30. The frame 23 and the cover plate body 21 are integrally formed, for example, by injection molding or die casting. It can be understood that the frame 231 and the cover plate body 21 are an integrated structure. Therefore, compared with the traditional split structure design, there is no seam problem in this utility model, which greatly improves the overall sealing performance of the measuring cavity 231 and can effectively prevent external moisture or other contaminants from entering the sensor, thereby protecting the circuit board from damage. In addition, the integrated structure design also enhances the structural rigidity of the measuring wall 23, enabling it to maintain a stable working state under vibration or impact environments. Compared with the multi-part assembly method of the traditional split structure design, the integrated molding significantly reduces the number of parts and assembly steps. For example, there is no need to separately process the measuring cavity shell and perform sealing connection; the cover plate and measuring cavity can be manufactured in one molding, reducing production costs and process difficulty, and improving production efficiency and product consistency.

[0037] Please see Figure 1 and Figure 2As shown, in this embodiment, the measuring wall 23 is disposed on the side of the cover plate body 21 facing the circuit board 30, and is partially embedded in the cover plate body 21, and is sealed to the cover plate body 21. For example, the frame 23 is partially embedded in the cover plate body 231, and a tight connection is achieved by means of sealant, welding or ultrasonic welding. Specifically, the frame 23 can be prefabricated as an independent component, and then embedded into the reserved groove of the cover plate body 21, and the connection between the two is ensured to be leak-free by appropriate sealing means.

[0038] Understandably, since the measuring wall 23 is directly formed by the cover plate body 21, and the air intake path is that external gas enters the measuring chamber 231 through the breathable membrane 22 covering the air inlet 211, the entire measured airflow is confined within the closed channel inside the cover plate assembly 20, and the rest of the circuit board 30 is not directly exposed to the measured environment. Therefore, even during long-term operation in high humidity, dusty, or oil mist environments, moisture is unlikely to penetrate the sensor housing 10, thus avoiding the need for additional protection of the circuit board, simplifying the manufacturing process, and improving product reliability and maintenance convenience.

[0039] Please see Figure 1 and Figure 2 As shown, in this embodiment, the frame 23 and the circuit board 30 are sealed together to seal and isolate the internal cavity of the sensor housing 10 and the measuring cavity 231. For example, sealant 232 is filled between the surface of the frame 23 and the circuit board 30 along the circumference of the measuring cavity 231 to achieve complete sealing and isolation between the internal cavity of the sensor housing 10 and the measuring cavity 231. Specifically, the sealant 232 is continuously applied along the entire circumference of the frame 23 to form a complete sealing barrier. Its filling path extends from the bottom of the frame of the cover body 21 to the surface of the circuit board 30, completely covering the joint area between the two to ensure no leakage channels. The width of the sealant 232 is greater than the thickness of the frame 23. The sealant is present on both the inner and outer sides of the frame 23, and its thickness is greater than the gap between the frame 23 and the circuit board to ensure sufficient filling and form a raised sealing structure, thereby improving sealing reliability. Of course, in some other embodiments, a sealing ring or sealing gasket or other sealing structure can also be provided at the end of the frame 23 facing the circuit board 30 to achieve a sealed connection between the frame 23 and the circuit board 30.

[0040] Please see Figure 1 , Figure 2 and Figure 3As shown, in this embodiment, a positioning guide groove 212 is formed on the side of the cover plate body 21 facing away from the circuit board 30, and the positioning guide groove 212 is arranged around the air inlet 211. Specifically, in this embodiment, the size of the positioning guide groove 212 gradually increases towards the side facing away from the circuit board 30 to form a sloping sidewall, that is, the cross-section of the positioning guide groove 212 is a trapezoid with a wider top and a narrower bottom, and its width or diameter gradually increases from the bottom of the groove towards the direction facing away from the circuit board 30, forming an inclined sidewall. It should be noted that when the positioning guide groove 212 is a circular groove, the size refers to the diameter of the circular groove; when the positioning guide groove 212 is a rectangular groove, the size refers to the length and / or width of the groove. It can be understood that the sloping sidewall can play a good guiding role when installing the breathable membrane. During the assembly process, even if there is a slight positional deviation, the breathable membrane can automatically slide into the bottom of the groove along the sloping surface to achieve self-centering, reduce assembly difficulty, and improve assembly efficiency.

[0041] Please see Figure 1 , Figure 2 and Figure 3 As shown in this embodiment, in the actual working environment of the sensor, external moisture may adhere to the outer surface of the sensor. To prevent liquid water from accumulating around the air inlet 211 or seeping into the positioning guide groove 212, thereby affecting the normal air permeability of the breathable membrane 22 or causing erroneous measurements, a drainage slope 213 is designed on the outer surface of the cover plate body 21 in this embodiment. Specifically, the drainage slope 213 starts from the bottom of the positioning guide groove 212 and extends radially away from the air inlet 211 to the outer surface of the cover plate body 21, and smoothly transitions with the outer surface of the cover plate body 21. This slope structure forms an outward drainage channel, which can effectively guide the water remaining on the sensor surface to slide down quickly along the slope, avoiding liquid accumulation near the air inlet. In addition, even if a small amount of water droplets come into contact with the surface of the breathable membrane 22, they will be quickly drained away under the guidance of gravity and the slope, and will not cover the air inlet area for a long time, thereby ensuring the continuity of gas flow and the accuracy of measurement.

[0042] It is understood that in this embodiment, one end of the sensor housing 10 is provided with a connector 11, which is used to install and connect with the vehicle's air intake system. After the sensor is installed, it is arranged vertically or at an angle. The end of the drainage slope 213 away from the breathable membrane 22 faces downward, so that the liquid can be discharged along the drainage slope 213 under the action of gravity.

[0043] Please see Figure 1 , Figure 2 and Figure 3As shown, in this embodiment, in the radial outward direction along the air inlet 211, the angle α between the drainage slope 213 and the surface of the cover plate body 21 is smaller than the angle β between the sidewall of the positioning guide groove 212 and the surface of the cover plate body 21. A smaller angle α means that the drainage slope 213 is gentler, which is conducive to the smooth and continuous outward flow of liquid under the combined action of surface tension and gravity, avoiding water jumping or splashing due to an excessively steep slope, or stagnation due to an excessively gentle slope. A gentle slope is more conducive to the formation of a continuous water film, improving the drainage effect. Furthermore, by setting the angle α to be smaller than the angle β, the sidewall of the positioning guide groove 212 maintains a relatively steep inclination angle, while the drainage area uses a gentler slope, achieving performance optimization of both positioning guidance and drainage guidance functions without interference between them.

[0044] Please see Figure 1 , Figure 2 and Figure 3 As shown, in this embodiment, the breathable membrane 22 is fixedly connected to the cover plate body 21 by ultrasonic welding or adhesive to achieve reliable sealing and long-term stable installation of the breathable membrane at the air inlet 211. The breathable membrane 22 covers the air inlet 211 on the outer surface of the cover plate body 21, allowing gas molecules to pass through while blocking contaminants such as liquid water, dust, and oil mist.

[0045] Please see Figure 1 , Figure 2 and Figure 3 As shown, in this embodiment, a welding surface is provided on the outer area of ​​the cover plate body 21 corresponding to the air inlet 211. After the breathable membrane 22 is placed on it, high-frequency vibration and pressure are applied by the ultrasonic welding head, causing the membrane material to partially melt and fuse with the cover plate body. For example, a welding rib 214 is provided around the bottom of the positioning guide groove 212 around the air inlet 211. The breathable membrane 22 is ultrasonically welded and fixed to the cover plate body 21 through the welding rib 214. That is, a ring of raised structure, namely the welding rib 214, is provided circumferentially at the bottom of the positioning guide groove 212, on the side near the air inlet 211. The height of the welding rib 214 is usually 0.1 to 0.3 mm, and the top is pointed or rounded, which facilitates the concentration of energy during the ultrasonic welding process, rapid melting and pressing into the back of the breathable membrane 22 to form a strong fusion interface. During installation, the breathable membrane 22 is aligned and installed through the positioning guide groove 212 and covers the air inlet 211. Then, ultrasonic welding is performed. Pressure and vibration are applied to the welding head, and the welding rib 214 is partially melted and fused with the breathable membrane 22. After cooling, a continuous annular weld is formed, achieving an airtight connection.

[0046] This invention proposes a humidity sensor that integrates the measuring chamber wall, the breathable membrane 22, and the cover plate body 21 into a modular design. Compared to traditional split structures, this embodiment effectively reduces the number of parts, simplifies assembly steps, and lowers production costs. Furthermore, by integrally molding the measuring chamber frame with the cover plate body, this embodiment eliminates the seam between the housing and the measuring chamber, forming a sealed measuring chamber. This reduces the adhesive application amount from 2.5g to 0.5g compared to traditional independent measuring chamber solutions, significantly reducing adhesive application and eliminating one installation step, thus effectively lowering production costs.

[0047] The above embodiments are merely illustrative of the principles and effects of this utility model and are not intended to limit the scope of this utility model. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this utility model. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this utility model should still be covered by the claims of this utility model.

Claims

1. A humidity sensor, characterized in that, include: A sensor housing, wherein a circuit board is installed inside the sensor housing, and a detection element is provided on the circuit board; Cover plate assembly, the cover plate assembly comprising: The cover plate body has an air inlet. A frame is disposed on the side of the cover plate body facing the circuit board and arranged around the air inlet. The frame and the surface of the circuit board enclose a measuring cavity, and the detection element is located inside the measuring cavity.

2. The humidity sensor according to claim 1, characterized in that, The frame extends toward the circuit board, and the frame and the cover plate body are an integral structure.

3. The humidity sensor according to claim 1, characterized in that, The frame portion is embedded within the cover plate body and is sealed to the cover plate body.

4. The humidity sensor according to claim 1, characterized in that, Along the circumference of the measuring cavity, the frame is sealed to the circuit board to seal and isolate the chamber of the sensor housing from the measuring cavity.

5. The humidity sensor according to claim 4, characterized in that, The surfaces of the circuit board within the enclosure are filled with sealant to achieve a sealed connection.

6. The humidity sensor according to claim 1, characterized in that, It also includes a breathable membrane, which is disposed on the side of the cover plate body opposite to the circuit board and covers the air inlet.

7. The humidity sensor according to claim 6, characterized in that, The breathable membrane is fixedly connected to the cover plate body by ultrasonic welding or adhesive.

8. The humidity sensor according to claim 6, characterized in that, The cover plate body has a positioning guide groove on the side facing away from the circuit board. The positioning guide groove is arranged around the air inlet and is used to position and guide the breathable membrane.

9. The humidity sensor according to claim 8, characterized in that, The dimensions of the positioning guide groove gradually increase toward the side facing away from the circuit board to form a sloping sidewall.

10. The humidity sensor according to claim 8, characterized in that, The cover plate body is also provided with a drainage slope on the side away from the circuit board. The drainage slope extends from the bottom of the positioning guide groove toward the surface of the cover plate body in a direction away from the air inlet.

11. The humidity sensor according to claim 10, characterized in that, In the direction radially outward from the air inlet, the angle between the drainage slope and the surface of the cover plate body is smaller than the angle between the sidewall of the positioning guide groove and the surface of the cover plate body.

12. The humidity sensor according to claim 8, characterized in that, The bottom of the positioning guide groove is provided with welding ribs around the air inlet, and the breathable membrane is welded and fixed to the cover plate body through the welding ribs.

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