A pressure sensor

Abstract

The present invention discloses a pressure sensor, which includes a cover body and a housing detachably connected; an internal space is formed between the cover body and the housing; a circuit board is installed at the lower end of the cover body, and the circuit board divides the internal space into an upper space and a lower space that are isolated from each other; a flexible pipe is provided in the lower space to absorb oil and water; one end of the flexible pipe is communicated with a through hole on the circuit board, and the other end thereof is communicated with a lower nozzle. The flexible pipe of the present invention has strong adsorption capacity and large surface area of the pipe wall, and does not hinder the transmission of pressure, so as to achieve the effect of neither affecting the sensitivity and accuracy of the sensor nor significantly improving the reliability and service life of the sensor.

Description

Technical Field

[0001] The present invention belongs to the technical field of aircraft instruments and meters, and particularly relates to a pressure sensor dedicated for fighter planes. Background Art

[0002] An aircraft is a large and very sophisticated flying vehicle. Whether it can operate normally is not only related to the personal safety of the crew members, but also related to whether the aircraft can complete its mission. A pressure sensor is a scout for monitoring the operation of an aircraft, which can timely detect sudden problems and potential problems of the aircraft.

[0003] The pressure sensor for this aircraft is made based on the principle that single-crystalline silicon material has piezoresistive effect. On a specific crystal plane of single-crystalline silicon, a specific crystal orientation is selected, and a group of piezoresistors are fabricated by using semiconductor planar technology and connected into a Wheatstone bridge. When the silicon diaphragm is subjected to a pressure signal, the resistance values of a pair of bridge arms of the bridge increase, and the resistance values of the other pair of bridge arms decrease accordingly, and the change in the resistance value is proportional to the pressure. When an excitation voltage is supplied to the bridge, the change in the resistance value can be converted into a voltage signal. Since the output voltage is proportional to the pressure, the purpose of measuring the pressure magnitude is achieved.

[0004] The pressure sensor is installed in the ventilation box of the aircraft. As the pressure changes, when the gas transmitting the pressure enters the pressure sensor, a small amount of water and oil are easily brought in. It is very difficult to take out the water and oil that enter the interior of the sensor, and the attachment to the core body or the circuit board is likely to cause the sensor to malfunction. Summary of the Invention

[0005] The purpose of the present invention is to provide a pressure sensor for the above-mentioned deficiencies in the prior art, which can not only not affect the sensitivity and accuracy of the sensor, but also greatly improve the reliability and service life of the sensor.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] A pressure sensor, which includes a cover body and a housing detachably connected; an internal space is formed between the cover body and the housing; a circuit board is installed at the lower end of the cover body, and the circuit board divides the internal space into an upper space and a lower space that are isolated from each other; a flexible pipe is provided in the lower space to absorb oil and water; one end of the flexible pipe is communicated with a through hole on the circuit board, and the other end is communicated with a lower nozzle.

[0008] Further, an installation cavity is formed in the cover body, the installation cavity is communicated with the internal space, and a chip is installed in the installation cavity, and the chip is electrically connected to the circuit board; an upper nozzle communicated with the installation cavity is further provided on the cover body.

[0009] Further, the lower nozzle is installed on the housing; a socket electrically connected to the circuit board is installed on the housing.

[0010] Further, the flexible pipe includes a structural mesh pipe, and a hydrophilic adsorption layer and a lipophilic adsorption layer are provided on the structural mesh pipe.

[0011] Further, the cross-sections of both the hydrophilic adsorption layer and the lipophilic adsorption layer are C-shaped, and the two ends of the C-shaped hydrophilic adsorption layer and the two ends of the lipophilic adsorption layer cooperate with each other to form a closed pipe.

[0012] Further, the cross-section of the lipophilic adsorption layer is C-shaped and is provided on a part of the surface of the structural mesh pipe; the cross-section of the hydrophilic adsorption layer is O-shaped and is provided on the surfaces of the remaining structural mesh pipe and the surface of the lipophilic adsorption layer; the lipophilic adsorption layer is located between the structural mesh pipe and the hydrophilic adsorption layer.

[0013] Further, the flexible pipe is spirally wound in the lower space.

[0014] Further, the flexible pipe is a corrugated pipe.

[0015] Further, the flexible pipe is detachably connected to the circuit board, and the flexible pipe is detachably connected to the lower nozzle.

[0016] Further, the material of the hydrophilic adsorption layer is superabsorbent fiber; the material of the lipophilic adsorption layer is superlipophilic cotton fabric.

[0017] The pressure sensor provided by the present invention has the following beneficial effects:

[0018] 1. The tube wall of the flexible pipe of the present invention has strong adsorption ability and large surface area, and does not hinder the transmission of pressure, so as to achieve both not affecting the sensitivity and accuracy of the sensor and greatly improving the reliability and service life of the sensor.

[0019] 2. The present invention provides a flexible pipe in the internal space, which has the function of absorbing oil and water, and is used to absorb a small amount of water and oil brought in from the lower nozzle.

[0020] 3. The present invention provides a structural mesh pipe in the flexible pipe to support the entire pipe to keep the flexible pipe in a smooth state and avoid the pipe being flattened and affecting the pressure transmission.

[0021] 4. The flexible pipe of the present invention can be spirally wound in the lower space to increase the pipe length and the adsorption area of the tube wall.

[0022] 5. The flexible pipe of the present invention can be a corrugated pipe, and the pore diameter of its tube wall changes, which can further increase the surface area of the tube wall and has a larger adsorption area. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic structural diagram of the present invention.

[0024] Figure 2 It is a schematic structural diagram of a flexible pipe.

[0025] Figure 3 It is a schematic structural diagram of another flexible pipe.

[0026] Figure 4 It is a schematic distribution diagram of the second flexible pipe of the present invention.

[0027] Figure 5 It is a schematic distribution diagram of the third flexible pipe of the present invention.

[0028] Figure 6 It is a schematic structural diagram of the comparative example.

[0029] Among them, 100 is the cover body; 101 is the installation cavity; 102 is the upper connection nozzle; 200 is the housing; 201 is the lower connection nozzle; 202 is the socket; 300 is the core body; 400 is the circuit board; 401 is the through hole; 500 is the flexible pipe; 501 is the structural mesh pipe; 502 is the hydrophilic adsorption layer; 503 is the lipophilic adsorption layer; 600 is the filter layer. Specific embodiments

[0030] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

[0031] It should be noted that all the directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative position relationship and movement conditions between components in a specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indications will also change accordingly.

[0032] In the present invention, unless otherwise clearly defined and limited, the terms "connection", "fixation", etc. shall be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication of two components or the interaction relationship between two components, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0033] In addition, in the present invention, descriptions such as "first" and "second" are for descriptive purposes only, and should not be construed as indicating or implying their relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions between various embodiments may be combined with each other, but it must be based on the fact that those of ordinary skill in the art can implement it. When the combination of technical solutions conflicts with each other or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0034] Embodiment 1, referring to Figure 1 , the pressure sensor of this solution includes a cover body 100 and a housing 200 that are detachably connected. A closed internal space is formed between the cover body 100 and the housing 200. A circuit board 400 is installed at the lower end of the cover body 100. The circuit board 400 divides the internal space into an upper space and a lower space that are isolated from each other. A through hole 401 is opened on the circuit board 400 for communicating the upper space and the lower space.

[0035] In actual application, the circuit board 400 does not directly contact the housing 200. Therefore, the upper space and the lower space are only the upper and lower spaces in terms of space, and the two spaces are connected. However, in order to ensure 100% the connection state between the upper space and the lower space (to avoid hindering pressure transmission) and to prevent the connection state from being blocked due to reasons such as different thermal expansion coefficients, the circuit board 400 is provided with a through hole 401 for communicating the upper space and the lower space, so as to ensure the consistency of the pressure between the upper space and the lower space.

[0036] The circuit board 400 of the present invention is not a structural member in the sensor. As an electrical component, in order to better extend its service life, a buffer pad is provided between the cover body 100 and the circuit board 400, which can reduce the vibration of the circuit board 400.

[0037] In the present invention, a flexible pipe 500 is provided in the lower space for absorbing oil and water. One end of the flexible pipe 500 is communicated with the through hole 401 on the circuit board 400, and the other end is communicated with the lower nozzle 201.

[0038] As a further solution for the cover body 100 of this embodiment, the cover body 100 and the housing 200 can be connected by a threaded connection method, or can be connected by a snap connection method, or other detachable methods. However, due to the special working environment of the aircraft, the threaded connection method is preferably used in this embodiment.

[0039] An installation cavity 101 is formed inside the cover body 100. The installation cavity 101 is in communication with the internal space, specifically with the upper space. A core body 300 is installed in the installation cavity 101. The core body 300 is the main part of the pressure sensor piezoresistive component. The chip divides the installation cavity 101 into upper and lower cavities, and senses the pressure difference between the upper and lower cavities. And the chip is electrically connected to the circuit board 400.

[0040] The cover body 100 is provided with an upper connection nozzle 102 communicating with the installation cavity 101. The upper connection nozzle 102 actually communicates with the upper cavity of the installation cavity 101.

[0041] As a further solution for the housing 200 of this embodiment, a socket 202 and a lower connection nozzle 201 communicating with the lower space are installed on the housing 200. The socket 202 is electrically connected to the circuit board 400, and the circuit board 400 is electrically connected to the core body 300. The sensor introduces electricity into the circuit board 400 and the core body 300 through the socket 202, and at the same time transmits the pressure signal through the socket 202.

[0042] In this embodiment, since the through hole 401 of the circuit board 400 and the lower connection nozzle 201 are connected by a flexible pipe 500 that can absorb water and oil, and the flexible pipe 500 is unobstructed, the pressure transmission will not be affected. The pipe wall of the flexible pipe 500 can absorb water and oil, and can adsorb a small amount of water and oil brought in from the lower connection nozzle 201 on the pipe wall, avoiding the free collection and even flow of these water and oil in the closed internal space. Since the flexible pipe 500 is more water-absorbing and more oil-absorbing than the circuit board 400, the core body 300 and the housing 200, a small amount of water and a small amount of oil mixed into the sensor will always be infiltrated on the pipe wall of the flexible pipe 500. The pipe wall of the flexible pipe 500 has a strong adsorption capacity and a large surface area, thus achieving neither affecting the sensitivity and accuracy of the sensor nor significantly improving the reliability and service life of the sensor.

[0043] Embodiment 2. The flexible pipe 500 of this embodiment includes a structural mesh pipe 501, and a hydrophilic adsorption layer 502 and an oleophilic adsorption layer 503 provided on the structural mesh pipe 501.

[0044] Among them, the structural mesh pipe 501 is used to support the hydrophilic adsorption layer 502 and the oleophilic adsorption layer 503, so that the flexible pipe 500 always remains unobstructed, avoiding the pipe from being flattened and affecting the pressure transmission. And the structural mesh pipe 501 does not affect the passage of gas, water and oil through the pipe wall, so that water is adsorbed by the hydrophilic adsorption layer 502 and oil is adsorbed by the oleophilic adsorption layer 503.

[0045] Reference Figure 2 and Figure 3, what is shown in the figure is the situation where the hydrophilic adsorption layer 502 and the lipophilic adsorption layer 503 are both attached to the outer surface of the structural mesh tube 501. In actual applications, the hydrophilic adsorption layer 502 and the lipophilic adsorption layer 503 can also be attached to the inner surface of the structural mesh tube 501. Therefore, it should be understood that the two attachment methods of the hydrophilic adsorption layer 502 and the lipophilic adsorption layer 503 should both be within the protection scope of the present invention.

[0046] As an implementation scheme of the flexible tube in this embodiment, refer to Figure 2 , the cross-sections of both the hydrophilic adsorption layer 502 and the lipophilic adsorption layer 503 are C-shaped, and the two ends of the C-shaped hydrophilic adsorption layer 502 and the two ends of the lipophilic adsorption layer 503 cooperate with each other to form a closed pipeline. This closed pipeline can be of various shapes, such as a polygon. In this embodiment, it is preferably an O-shaped pipeline.

[0047] Figure 2 As shown in , the hydrophilic adsorption layer 502 and the lipophilic adsorption layer 503 each account for 50%. In fact, when in use, according to the water-oil ratio of different working environments, such as the ratio between the hydrophilic adsorption layer 502 and the lipophilic adsorption layer 503 being 3:7, 4:6, etc., the usage ratio of one of the materials can be increased or decreased to avoid one of the materials reaching the saturation state first, and the service life of the sensor can be maximally increased.

[0048] As another implementation scheme of the flexible tube in this embodiment, refer to Figure 3 , however, in the above structure, the C-shaped two ends of the hydrophilic adsorption layer 502 are respectively connected to the C-shaped two ends of the lipophilic adsorption layer 503, and its manufacturing process is relatively complex. For the convenience of manufacturing.

[0049] Such as Figure 3 shown, it shows the structure of another flexible pipeline 500. The cross-section of the lipophilic adsorption layer 503 is C-shaped and is arranged on a part of the surface of the structural mesh tube 501; the cross-section of the hydrophilic adsorption layer 502 is O-shaped and is arranged on the remaining surface of the structural mesh tube 501 and the surface of the lipophilic adsorption layer 503; the lipophilic adsorption layer 503 is located between the structural mesh tube 501 and the hydrophilic adsorption layer 502.

[0050] During manufacturing, only need to attach the lipophilic adsorption layer 503 along the axial direction of the structural mesh tube 501 to the outer wall of the structural mesh tube 501, and then wind the hydrophilic adsorption layer 502 around the structural mesh tube 501 and the lipophilic adsorption layer 503 for fixation. Its operation is simple, with high efficiency and low cost.

[0051] In an environment with a relatively high proportion of oil-water doping, in order to further extend the service life of the entire sensor, the flexible pipe 500 is designed to be a replaceable structure. The flexible pipe 500 is detachably connected to the circuit board 400 and the lower nozzle 201. The overall life of the sensor can be greatly extended by regularly replacing the flexible pipe 500.

[0052] It should be noted that in this embodiment Figure 3 the form shown is with the oilophilic adsorption layer 503 inside and the hydrophilic adsorption layer 502 outside. It is also possible to adopt the form with the hydrophilic adsorption layer 502 inside and the oilophilic adsorption layer 503 outside. That is, both of these two distribution methods fall within the protection scope of the present invention.

[0053] Example 3, refer to Figure 4 , in order to further extend the service life of the pressure sensor, on the basis of Example 1, this embodiment gives a distribution method of the flexible pipe 500. The flexible pipe 500 is spirally wound in the lower space, increasing the length of the flexible pipe 500, that is, increasing the adsorption area of the pipe wall for water and oil, and can greatly improve the durability of the pressure sensor. At the same time, the spiral winding can generate centrifugal force when the gas passes through, throwing water and oil onto the pipe wall, further reducing the probability of water and oil passing through the flexible pipe 500.

[0054] Since the cover 100 and the housing 200 are preferably still connected by a threaded connection, the two ends of the flexible pipe 500 are respectively connected to the through hole 401 of the circuit board 400 and the lower nozzle 201. During the process of screwing the cover 100 into the housing 200, the flexible pipe 500 will naturally form a spiral shape while the cover 100 and the housing 200 rotate in threads.

[0055] As another distribution method of the flexible pipe 500, refer to Figure 5 , in order to further extend the service life of the pressure sensor, on the basis of the above embodiment, the flexible pipe 500 is designed as a corrugated pipe. Due to the change in the pipe diameter of the corrugated pipe, the airflow passing through will have a radial surge, which is beneficial for the water and oil brought in by the airflow to contact the pipe wall, further reducing the probability of water and oil passing through the flexible pipe 500. At the same time, compared with a straight pipe, the corrugated pipe has a larger pipe wall surface area, and the service life of the pressure sensor is further extended.

[0056] The hydrophilic adsorption layer 502 in the above embodiments of the present invention can be made of existing superabsorbent fibers, and its water absorption capacity far exceeds that of natural cotton, which can greatly improve the water absorption saturation capacity. The oilophilic adsorption layer 503 is made of existing superoleophilic cotton fabrics.

[0057] Comparative example:

[0058] Refer toFigure 6 The difference in structure between this comparative example and Embodiment 1 lies in that instead of adopting the connection structure of the flexible pipeline 500, the structure of the filter layer 600 is adopted. The filter layer 600 can also absorb water and oil. The filter layer 600 is arranged in the housing 200, dividing the space of the housing 200 into upper and lower parts. The gas, water, and oil entering from the lower connection nozzle 201 must pass through the filtration of the filter layer 600 before being transmitted upward. However, the working principle of the filter layer 600 relies on pressure driving, and a pressure difference between the two sides of the filter layer 600 is required to achieve it. Through experiments, it is found that the filter layer 600 will affect the pressure transmission and the accuracy of the sensor. Although this defect can be compensated by correcting the output signal of the sensor, as the usage time increases, the filter layer 600 continuously filters water and oil, its pores are continuously blocked by water and oil, and its permeability also changes accordingly. Then, its influence on pressure transmission will also change, and it cannot be compensated by correction. Therefore, the comparative example cannot achieve the purpose of neither affecting the sensitivity and accuracy of the sensor nor significantly improving the reliability and service life of the sensor.

[0059] Although the specific implementation manners of the invention have been described in detail with reference to the accompanying drawings, it should not be construed as a limitation on the protection scope of this patent. Within the scope described in the claims, various modifications and deformations that can be made by those skilled in the art without creative efforts still fall within the protection scope of this patent.

Claims

1. A pressure sensor, characterized in that: It includes a cover body and a housing that are detachably connected; an internal space is formed between the cover body and the housing; a circuit board is installed at the lower end of the cover body, and the circuit board divides the internal space into an upper space and a lower space that are isolated from each other; a flexible pipe is provided in the lower space to absorb oil and water; one end of the flexible pipe communicates with a through hole on the circuit board, and the other end thereof communicates with a lower connecting nozzle. The lower connecting nozzle is installed on the housing; a socket electrically connected to the circuit board is installed on the housing. The flexible pipe includes a structural mesh pipe, and a hydrophilic adsorption layer and a lipophilic adsorption layer are provided on the structural mesh pipe. The cross-section of the lipophilic adsorption layer is C-shaped and is provided on a part of the surface of the structural mesh pipe; the cross-section of the hydrophilic adsorption layer is O-shaped and is provided on the remaining surface of the structural mesh pipe and the surface of the lipophilic adsorption layer; the lipophilic adsorption layer is located between the structural mesh pipe and the hydrophilic adsorption layer.

2. The pressure sensor according to claim 1, wherein: An installation cavity is formed in the cover body, the installation cavity communicates with the internal space, and a chip is installed in the installation cavity, and the chip is electrically connected to the circuit board; an upper connecting nozzle communicating with the installation cavity is further provided on the cover body.

3. The pressure sensor according to claim 1, wherein: The flexible pipe is spirally wound in the lower space.

4. The pressure sensor according to any one of claims 1-3, characterized in that: The flexible pipe is a corrugated pipe.

5. The pressure sensor according to any one of claims 1-3, characterized in that: The flexible pipe is detachably connected to the circuit board, and the flexible pipe is detachably connected to the lower connecting nozzle.

6. The pressure sensor according to claim 1, wherein: The material of the hydrophilic adsorption layer is superabsorbent fiber; the material of the lipophilic adsorption layer is superlipophilic cotton fabric.

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