Pressure damping structure and pressure sensor

Abstract

A pressure damping structure for a pressure sensor comprises a pressure introduction channel which is formed on a shell of the pressure sensor to introduce a pressure medium to be measured and is provided with a longitudinal extension part; the retaining seat is fixed in the pressure introduction channel and is provided with a transversely extending taper hole; the elements are fixed in the longitudinal extension part and comprise a first elastic film and a second elastic film which are used for sealing the taper hole from the two sides respectively so as to define an airtight cavity with reference pressure, and the outer side of the first elastic film is exposed to the pressure medium to be measured with a smaller exposure area than the outer side of the second elastic film; the connecting column transversely extends into the airtight cavity, and the two ends of the connecting column are connected to the centers of the inner sides of the first elastic film and the second elastic film respectively; the pressure sensitive assembly can be effectively protected from the risk of pressure pulse damage.

Description

Technical Field

[0001] This invention belongs to the field of pressure detection technology, specifically a pressure damping structure and a pressure sensor. Background Technology

[0002] Pressure sensors are used to measure the pressure of an environment or medium. Currently, they are mostly implemented using MEMS (Micro-Electro-Mechanical Systems), which utilize the piezoresistive effect of semiconductor silicon to measure pressure. In this system, a diaphragm is positioned in the center of the silicon core. The pressure applied to the silicon diaphragm from both sides causes a change in the resistance of doped resistors on the diaphragm. The current or voltage signal output by the measurement circuit, composed of several connected resistors, is further processed by a conditioning circuit before the measurement result is output. When a vacuum cavity is provided on one side of the diaphragm within the silicon chip, the measured pressure is the pressure applied to the other side relative to the vacuum, i.e., absolute pressure. When atmospheric pressure is introduced to one side of the diaphragm, the measured pressure is the pressure relative to the atmosphere, i.e., gauge pressure. When other pressures are introduced to both sides of the diaphragm, the measured pressure is the difference between the two pressures, i.e., differential pressure. In some other sensors, a temperature-sensitive element can also be integrated to simultaneously measure the pressure and temperature of the medium.

[0003] In the structure of a pressure sensor, the pressure-sensitive component is the core component. It typically contacts the medium being measured through a pressure inlet channel, converting pressure into an electrical signal. However, in practical applications, the pressure medium may generate pressure pulses, which can impact the pressure-sensitive component, affecting measurement accuracy or even damaging it. Summary of the Invention

[0004] The purpose of this invention is to provide a pressure damping structure and a pressure sensor to solve at least one of the above-mentioned technical problems.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: Pressure damping structures for pressure sensors include: A pressure introduction channel formed on the housing of the pressure sensor to introduce the pressure medium to be measured has a longitudinally extending portion. The retaining seat fixed within the pressure inlet channel has a laterally extending tapered hole; The components fixed inside the longitudinally extending portion include: a first elastic membrane and a second elastic membrane that respectively close the conical hole from both sides to form an airtight chamber with a reference pressure, wherein the outer side of the first elastic membrane is exposed to the pressure medium to be measured with a smaller exposure area than the outer side of the second elastic membrane; and a connecting column extending laterally inside the airtight chamber, wherein its two ends are respectively connected to the center of the inner side of the first elastic membrane and the second elastic membrane.

[0006] Preferably, the element is a one-piece element made of elastic material, and the connecting post is relatively rigid in the lateral direction compared to the first elastic membrane and the second elastic membrane.

[0007] Preferably, the retaining seat includes a tapered cylinder arranged laterally and whose inner cavity at least partially defines the tapered hole, a first annular connecting portion connected to one axial end of the tapered cylinder, and a second annular connecting portion connected to the other axial end of the tapered cylinder, wherein the edges of the first elastic membrane and the second elastic membrane are respectively sealed to the first annular connecting portion and the second annular connecting portion.

[0008] Preferably, the edges of the first elastic membrane and the second elastic membrane are respectively airtightly connected to a first sealing ring and a second sealing ring of the first annular connecting portion and the second annular connecting portion.

[0009] Preferably, the first annular connecting portion and the second annular connecting portion each have an annular receiving groove with an inner circumferential opening, and the first sealing ring body and the second sealing ring body are hermetically received in the corresponding annular receiving groove.

[0010] Preferably, the retaining seat is a thin-shell-shaped metal stamping part; the annular receiving groove is formed by the inner surface of the corresponding first annular connecting part or the second annular connecting part after being rolled inward at the end away from the cone, and the first sealing ring body and the second sealing ring body are pressed and sealed into the corresponding annular receiving groove.

[0011] Preferably, the end of the first annular connecting portion or the second annular connecting portion away from the cone extends radially outward along the outer surface of the second annular connecting portion to form a transition portion, and the outer periphery of the transition portion extends in the longitudinal plane to form a mounting plate; the mounting plate is inserted and fixed in the longitudinally extended portion.

[0012] Preferably, the longitudinally extending portion is disposed on the outermost side of the pressure introduction channel, and at least one slot extending longitudinally to the outer end of the pressure introduction channel is provided on its inner wall; the mounting plate is a flat plate, and at least one of its transverse ends is fitted into one of the slots.

[0013] Preferably, the mounting plate is tightly fitted within the longitudinal extension portion.

[0014] The present invention also provides a pressure sensor, including the pressure damping structure described above.

[0015] Compared with the prior art, the beneficial effects of the present invention are: This invention utilizes a first and second elastic membrane with different exposure areas within the pressure inlet channel of a pressure sensor. When the pressure medium acts on these membranes, the resultant force exerted by the medium on the element causes it to deflect to the left (from the second membrane to the first membrane) due to the smaller exposure area of ​​the first membrane and the larger exposure area of ​​the second membrane. This causes the first membrane to arch outward, forming a control gap with the inner wall of the pressure inlet channel to control the effective communication cross-section. This structural design ensures that the effective communication cross-section decreases with increasing pressure, thus achieving automatic control of the effective communication cross-section of the pressure inlet channel through the medium itself, effectively protecting the pressure-sensitive component from the risk of damage from pressure pulses. Furthermore, this design is simple, low-cost, and highly reliable, making it suitable for various pressure sensor applications requiring protection against pressure pulse damage. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the pressure sensor structure in this embodiment; Figure 2 for Figure 1 Enlarged view of a portion of point A in the middle; Figure 3 This is a three-dimensional sectional view of the pressure damping structure in this embodiment; Figure 4 This is a state diagram of the pressure damping structure when P1 equals P0 in this embodiment; Figure 5 This is a state diagram of the pressure damping structure when P1 is greater than P0 in this embodiment; In the diagram: P0, reference pressure; 1, housing; 1a, mounting cavity; 1s, airtight chamber; 10, pressure introduction channel; 101, longitudinal extension; 101a, slot; 11, outer shell; 12, end button; 121, terminal; 2, component; 20a, first sealing ring; 20b, second sealing ring; 21, first elastic membrane; 22, second elastic membrane; 23, connecting post; 3, retaining seat; 3a, conical hole; 3b, annular receiving groove; 31, conical cylinder; 32, first annular connecting part; 33, second annular connecting part; 34, transition part; 35, mounting plate; 4, pressure-sensitive component; 5, electronic module component; 51, circuit board. Detailed Implementation

[0017] The technical solution of this application will now be clearly and completely described with reference to the accompanying drawings. The following embodiments are exemplary and are only used to explain this application, and should not be construed as limiting this application. In the following description, the same reference numerals are used to denote the same or equivalent elements, and repeated descriptions are omitted.

[0018] In the description of this application, it should be understood that the terms "upper," "lower," "inner," "outer," "left," and "right," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this application is in use, or the orientation or positional relationship commonly understood by those skilled in the art. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the equipment or component referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. In addition, the prepositions "first," "second," and "third," etc., are only used for the purpose of distinguishing the modified objects, and should not be construed as indicating or implying relative importance.

[0019] Furthermore, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0020] It should also be further understood that the term "and / or" as used in this application specification and the corresponding claims refers to any combination of one or more of the listed items and all possible combinations.

[0021] like Figure 1 and Figure 2 As shown, this embodiment provides a pressure sensor, including a housing 1, a pressure-sensitive component 4, an electronic module component 5, and a pressure damping structure.

[0022] An installation cavity 1a is formed inside the housing 1. The bottom of the housing 1 is provided with a pressure inlet channel 10 that communicates with the installation cavity 1a for receiving the pressure medium to be measured.

[0023] The pressure introduction channel 10 has a longitudinal extension 101, which is located on the outermost side of the pressure introduction channel 10, and its inner wall has a slot 101a extending longitudinally to the outer end of the pressure introduction channel 10.

[0024] The housing 1 includes an outer shell 11 and an end button 12. The bottom of the end button 12 is sealed and fixedly connected to the top of the outer shell 11, forming an installation cavity 1a. The pressure introduction channel 10 is provided at the bottom of the outer shell 11.

[0025] The electronic module assembly 5 is fixedly installed within the mounting cavity 1a. Specifically, the electronic module assembly 5 includes a circuit board 51. The pressure-sensitive component 4 is fixedly mounted on the upper surface of the circuit board 51 by means such as adhesive bonding, and is electrically connected to the circuit on the circuit board 51 via leads to transmit the electrical signal generated by the pressure-sensitive component 4 to the circuit board 51 for processing. To enable the pressure medium to be measured to be transmitted to the sensing diaphragm of the pressure-sensitive component 4, the circuit board 51 has through holes (not labeled in the figure) extending through its upper and lower surfaces. The lower end of the through hole connects to one inner end of the pressure inlet channel 10, and its upper end is sealed and opposite to the pressure-sensitive component 4, thereby forming a continuous pressure transmission path, allowing the pressure-sensitive component 4 to be sealed within the pressure inlet channel 10 and receive the pressure medium to be measured.

[0026] The end button 12 is fitted with a plurality of terminals 121. One end of the terminal 121 is located outside the housing 1, and the other end passes through the end button 12 and extends into the mounting cavity 1a. It is electrically connected to the corresponding pads or contacts on the circuit board 51 through leads.

[0027] like Figure 1-5 As shown, this embodiment also provides a pressure damping structure for a pressure sensor, including a pressure introduction channel 10 formed on the housing 1 of the pressure sensor to introduce the pressure medium to be measured, the pressure introduction channel 10 having a longitudinally extending portion 101; a retaining seat 3 fixed in the pressure introduction channel 10 having a laterally extending tapered hole 3a; and an element 2 fixed inside the longitudinally extending portion 101.

[0028] A pressure inlet channel 10 is disposed on the housing 1 of the pressure sensor for introducing the pressure medium to be measured. The pressure inlet channel 10 includes a longitudinally extending portion 101 disposed on the outermost side of the pressure inlet channel 10, and at least one slot 101a extending longitudinally to the outer end of the pressure inlet channel 10 is provided on its inner wall. This design allows the pressure medium to be measured to enter the interior of the pressure sensor through the pressure inlet channel 10, while providing a mounting position for the retainer 3 and the element 2.

[0029] The retainer 3 is fixed within the pressure inlet channel 10 and has a laterally extending conical hole 3a. The retainer 3 includes a conical cylinder 31, a first annular connecting portion 32, and a second annular connecting portion 33. The conical cylinder 31 is arranged laterally, and at least partially defines the conical hole 3a; that is, at least a portion of the conical hole 3a is formed by the inner cavity of the conical cylinder 31, or the conical hole 3a is completely formed by the inner cavity of the conical cylinder 31. The first annular connecting portion 32 is connected to one axial end of the conical cylinder 31, and the second annular connecting portion 33 is connected to the other axial end of the conical cylinder 31. The retainer 3 is a thin-shell-shaped metal stamping part. This structural design gives the retainer 3 good strength and stability, enabling it to firmly support the element 2.

[0030] The first annular connecting portion 32 and the second annular connecting portion 33 each have an annular receiving groove 3b with an inner circumferential opening. The annular receiving groove 3b is surrounded by the inner surface of the corresponding first annular connecting portion 32 or second annular connecting portion 33 after being rolled inward at the end away from the cone 31. The end of the first annular connecting portion 32 or second annular connecting portion 33 away from the cone 31 extends radially outward along the outer surface of the second annular connecting portion 33 to form a transition portion 34, and the outer periphery of the transition portion 34 extends in the longitudinal plane to form a mounting plate 35. The mounting plate 35 is inserted and fixed in the longitudinal extension portion 101. The mounting plate 35 can be a flat plate, and at least one end of it is inserted into a slot 101a in a transverse direction. The mounting plate 35 is tightly fitted in the longitudinal extension portion 101, and this design ensures the ease of installation of the retainer 3 in the pressure introduction channel 10.

[0031] Element 2 is fixed inside the longitudinally extending portion 101. Element 2 includes a first elastic membrane 21, a second elastic membrane 22, and a connecting post 23. The first elastic membrane 21 and the second elastic membrane 22 respectively close the conical holes 3a from both sides to form an airtight chamber 1s, which has a reference pressure P0. The connecting post 23 extends laterally within the airtight chamber 1s, and its two ends are respectively connected to the center of the inner side of the first elastic membrane 21 and the second elastic membrane 22. The outer side of the first elastic membrane 21 is exposed to the pressure medium to be measured with a smaller exposure area than the outer side of the second elastic membrane 22; that is, the area of ​​the outer side of the first elastic membrane 21 exposed to the pressure medium to be measured is smaller than the area of ​​the outer side of the second elastic membrane 22 exposed to the pressure medium to be measured.

[0032] Component 2 is an integral component made of elastic material. The connecting post 23 has relative rigidity in the lateral direction compared to the first elastic membrane 21 and the second elastic membrane 22. That is, in the lateral direction, the rigidity of the connecting post 23 is greater than that of the first elastic membrane 21 and the second elastic membrane 22.

[0033] The edges of the first elastic membrane 21 and the second elastic membrane 22 are respectively sealingly connected to the first annular connecting portion 32 and the second annular connecting portion 33. Specifically, the edges of the first elastic membrane 21 and the second elastic membrane 22 are respectively airtightly connected to a first sealing ring 20a and a second sealing ring 20b of the first annular connecting portion 32 and the second annular connecting portion 33. The first sealing ring 20a and the second sealing ring 20b are airtightly accommodated in corresponding annular receiving grooves 3b. The first sealing ring 20a and the second sealing ring 20b are pressed and sealed into the corresponding annular receiving grooves 3b. This design ensures the sealing performance of the airtight chamber 1s.

[0034] Please refer to the following for details. Figure 4When the pressure P1 of the pressure medium to be measured is equal to the reference pressure P0 in the airtight chamber within 1 second, the center deflection of both the first elastic membrane 21 and the second elastic membrane is zero. At this time, the connecting column 23 extends from the inner center of the first elastic membrane 21 to the inner center of the first elastic membrane 21, and its length is equal to the distance between the planes containing the edges of the two elastic membranes.

[0035] During the operation of the pressure damping structure, when the pressure P1 of the medium under test is greater than the reference pressure P0 within the airtight chamber for 1 second, the area of ​​the first elastic membrane 21 exposed to the medium under test is smaller than the area of ​​the second elastic membrane 22 exposed to the medium under test. Therefore, the pressure P1 transmitted from the medium under test to the first elastic membrane 21 is less than the pressure transmitted to the second elastic membrane 22. The pressure transmitted from the medium under test to the second elastic membrane 22 is then transmitted to the first elastic membrane 21 through the connecting column 23, causing the first elastic membrane 21 to bulge to the left, forming a control gap with the inner wall of the pressure introduction channel 10 to control the effective communication cross-section. The larger the pressure P1 of the medium under test, the smaller the effective communication cross-section, and the greater the resistance when the pressure of the medium under test is transmitted through the pressure introduction channel 10 to the pressure-sensitive component 2 of the pressure sensor. This achieves automatic control of the effective communication cross-section of the pressure introduction channel 10 through the medium under test itself, thereby realizing the buffering and damping effect on the pressure. The connecting post 23 couples the deformations at the centers of the two elastic membranes. Through its rigidity, it ensures that the deflection at the center of the second elastic membrane 22 equals the deflection at the center of the first elastic membrane 21, resulting in a relatively small deformation. Consequently, the tension at the edges of the elastic membranes is smaller, causing the connecting post 23 to move to the left. From the perspective of the entire component 2, the tension at the edges of the elastic membranes is needed to balance the overall left-right pressure difference; therefore, the elastic membranes deform and arch to the left. Thus, the airtight chamber 1s must remain airtight during this process to prevent the pressure medium being measured from entering and causing the pressure on both sides of the elastic membranes to return to zero.

[0036] Therefore, in some other schemes, the length of the connecting post 23 is equal to that of the second elastic membrane 22, but it does not necessarily have to be equal to the distance between the planes on which its edges lie. Whether the connecting post 23 is too long or too short, as long as the pressure P1 is large enough, the first elastic membrane 21 can be made to arch to the left.

[0037] This pressure damping structure, through the synergistic action of the first elastic diaphragm 21, the second elastic diaphragm 22, and the connecting column 23, effectively reduces the impact of pressure fluctuations on the pressure sensor, thereby improving the measurement accuracy and service life of the pressure sensor. Simultaneously, the integrated component 2 design simplifies the structure and improves reliability, while the metal stamping structure and sealing design of the retainer 3 ensure the stability and sealing of the entire pressure damping structure.

[0038] It should be noted that although the present invention has been disclosed above with specific embodiments, the above embodiments are not intended to limit the present invention. Those skilled in the art can make various modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the scope defined in the claims.

Claims

1. Pressure damping structure for a pressure sensor, characterized in that, The pressure sensor comprises: a pressure introduction channel formed on the housing of the pressure sensor for introducing a pressure medium to be measured, the pressure introduction channel having a longitudinal extension; a retaining seat fixed in the pressure introduction channel, the retaining seat having a laterally extending tapered hole; and an element fixed inside the longitudinal extension, the element comprising: a first elastic membrane and a second elastic membrane respectively closing the tapered hole from two sides to form an airtight chamber having a reference pressure, the outer side of the first elastic membrane being exposed to the pressure medium to be measured with a smaller exposed area than the outer side of the second elastic membrane; and a connecting column laterally extending in the airtight chamber, two ends of the connecting column being respectively connected to the center of the inner side of the first elastic membrane and the second elastic membrane.

2. The pressure damping structure according to claim 1, characterized by, The element is an integral element made of an elastic material, the connecting column being relatively rigid in the lateral direction compared to the first elastic membrane and the second elastic membrane.

3. The pressure damping structure of claim 1, wherein The retaining seat comprises a tapered cylinder arranged laterally and having an inner cavity at least partially defining the tapered hole, a first annular connecting portion connected to an axial end of the tapered cylinder, and a second annular connecting portion connected to an axial end of the tapered cylinder opposite to the first annular connecting portion, edges of the first elastic membrane and the second elastic membrane being respectively sealingly connected to the first annular connecting portion and the second annular connecting portion.

4. The pressure damping structure according to claim 3, characterized by The edges of the first elastic membrane and the second elastic membrane are respectively airtightly connected to a first sealing ring body and a second sealing ring body of the first annular connecting portion and the second annular connecting portion.

5. The pressure damping structure according to claim 4, characterized by The first annular connecting portion and the second annular connecting portion each have an annular accommodating groove with an inner circumferential opening, the first sealing ring body and the second sealing ring body being airtightly accommodated in the corresponding annular accommodating groove.

6. The pressure damping structure according to claim 5, characterized by The retaining seat is a thin-shell metal stamping part; the annular accommodating groove is formed by the inner side surface of the corresponding first annular connecting portion or second annular connecting portion being rolled inward from an end away from the tapered cylinder, and the first sealing ring body and the second sealing ring body are tightly sealed in the corresponding annular accommodating groove.

7. The pressure damping structure according to claim 6, characterized by An end of the first annular connecting portion or the second annular connecting portion away from the tapered cylinder extends radially outward along the outer side surface of the second annular connecting portion to form a transition portion, an outer periphery of the transition portion extends in a longitudinal plane to form a mounting plate; the mounting plate is inserted and fixed in the longitudinal extension.

8. The pressure damping structure of claim 7, wherein The longitudinal extension is arranged at the outermost side of the pressure introduction channel, and an inner wall of the longitudinal extension is provided with at least one insertion slot extending longitudinally to an outer end of the pressure introduction channel; the mounting plate is a flat plate, and at least one end of the mounting plate is inserted into one of the insertion slots in a fitting manner.

9. The pressure damping structure according to any one of claims 1 to 8, characterized by, The mounting plate is tightly fitted in the longitudinal extension.

10. A pressure sensor, characterized by The pressure damping structure comprises the pressure sensor as claimed in any one of claims 1 to 9.

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