An ultrasonic sensor, meter module and gas meter

Abstract

The utility model discloses an ultrasonic sensor, metering module and gas meter, and the ultrasonic sensor includes: casing, piezoelectric ceramic, conducting layer, first matching layer and second matching layer, the casing includes metal cover and metal shell, and the bottom of metal shell is hollow, piezoelectric ceramic, conducting layer, first matching layer and second matching layer are sequentially laminated and set, and the first matching layer is bonded in the bottom of metal shell through encapsulation technology, piezoelectric ceramic and conducting layer are as positive and negative poles and are connected with conducting wire respectively. The sensor casing of the utility model adopts metal cover and metal shell, can effectively resist the interference of electromagnetic to signal, the sealed structure in the inside can reduce the influence of corrosive gas and water vapor to the sensor, and then can improve the performance and service life of gas meter, and the design of shock absorbing rubber gasket can expand the use temperature range of gas meter.

Description

Technical Field

[0001] This utility model relates to the field of ultrasonic measurement technology, and more specifically to an ultrasonic sensor, a metering module, and a gas meter. Background Technology

[0002] Ultrasonic gas meters, as precision instruments, have wide applications in the field of gas metering. The piezoelectric transducer, as the core component of an ultrasonic gas meter, converts mechanical energy into ultrasonic signals for transmission and reception. The performance of the piezoelectric transducer directly affects the measurement accuracy and stability of the gas meter.

[0003] Ultrasonic transducers rely on the time difference of ultrasonic waves propagation in the gas flow rate in the metering pipeline under the conditions of reverse and forward gas flow to calculate the gas flow rate. They are highly susceptible to interference from external electromagnetic fields, which can affect the measurement accuracy of the gas meter. Therefore, effective electromagnetic shielding of the transmitting and receiving components inside the transducer is crucial. Currently, many products on the market use plastic shells or semi-open metal shells, and almost no effective measures are taken to prevent electromagnetic interference.

[0004] Ultrasonic transducers are installed on gas metering pipelines and are directly exposed to the gas environment. Gas contains many corrosive substances and water vapor, which will have a negative impact on the internal components and adhesives of the transducer, thus affecting the measurement accuracy and the lifespan of the transducer. Therefore, the transducer needs to be sealed. The common sealing method is to pot the entire product with glue. Because the internal functional components of the transducer are bonded with glue, and the electrode solder joints will also be in direct contact with the potting glue, the adhesive and solder residue are in the potting glue for a long time. There will be mutual reactions between them and the glue will cause the glue to delaminate, which will lead to sealing failure or affect the function of the product. In addition, the potting process usually requires a long time of heat curing, which will also reduce the production efficiency and is not conducive to the implementation of automated production.

[0005] To avoid the effects of external vibrations caused by rigid installation, transducers typically use rubber elastomers for shock absorption and sealing. However, rubber elastomers exhibit significant hardening at low temperatures. Furthermore, the rubber elastomers in existing products are not designed with proper contact area and force direction, resulting in near-rigid support for the transducer under hardening conditions, which affects the product's performance.

[0006] Therefore, there is an urgent need to find a structural design that can resist electromagnetic interference while also meeting the requirements for product airtightness and vibration reduction performance. Utility Model Content

[0007] The description of this utility model introduces a series of simplified concepts, which will be further explained in detail in the detailed description section. This description is not intended to limit the key features and essential technical features of the claimed technical solution, nor is it intended to determine the scope of protection of the claimed technical solution.

[0008] To at least partially solve the above problems, this utility model proposes an ultrasonic sensor, comprising: a housing, a piezoelectric ceramic, a conductive layer, a first matching layer, and a second matching layer; the housing includes a metal cover plate and a metal outer shell, the bottom of the metal outer shell being hollowed out; the piezoelectric ceramic, the conductive layer, the first matching layer, and the second matching layer are sequentially stacked, the first matching layer being bonded to the bottom of the metal outer shell by an adhesive coating process; the piezoelectric ceramic and the conductive layer serve as positive and negative electrodes, respectively connected to wires.

[0009] Preferably, the metal casing has a radially extending flange portion and an axially extending cylindrical portion; the flange portion is stepped, including a first step and a second step, the outer diameter of the first step is larger than the outer diameter of the second step, the first step is higher than the second step in the axial direction, and the first step and the second step are connected by a radially extending step surface; the outer edge of the first step has petal-shaped protrusions arranged at equal intervals.

[0010] Preferably, the outer edge of the metal cover plate has claws arranged at equal intervals along the axial direction.

[0011] Preferably, the petal-shaped protrusions and claws are arranged alternately and fixed by mechanical riveting.

[0012] The beneficial effects of this solution are as follows: The ultrasonic sensor proposed in this solution has a metal housing. The metal cover and the metal outer shell are fixed by mechanical riveting to form an effective electromagnetic shielding cavity, which protects the internal functional components and effectively resists electromagnetic interference.

[0013] Preferably, the conductor is an FPC wire, and the grounding end of the FPC wire is soldered to the flange of the metal casing.

[0014] The beneficial effects of this solution are as follows: The ultrasonic sensor proposed in this solution uses FPC wire, which can effectively shield electromagnetic interference. At the same time, the grounding end of the FPC wire is electrically connected to the metal shell, which achieves a good electromagnetic shielding effect.

[0015] Preferably, it further includes an elastic sealing ring, the elastic sealing ring having a stepped cross-section, including a radially extending limiting portion and an axially extending limiting portion; the radially extending limiting portion includes an annular protrusion, an annular groove and another annular protrusion; the annular groove is located between the two annular protrusions.

[0016] Preferably, the elastic sealing ring is nested within a metal housing.

[0017] Preferably, it also includes an elastic sealing gasket that covers the elastic sealing ring.

[0018] The beneficial effects of this solution: The ultrasonic sensor proposed in this solution uses elastic sealing rings and elastic sealing gaskets, which further improves the airtightness of the product and prevents corrosive substances and moisture from entering the transducer and causing irreparable damage to the transducer.

[0019] Preferably, it further includes a shock-absorbing rubber washer, which includes a first sealing part on the radially inner side and a second sealing part on the radially outer side, the axial thickness of the second sealing part being greater than the axial thickness of the first sealing part; the lower surface of the second sealing part is provided with a downwardly protruding axial sealing protrusion; the periphery of the second sealing part is radially protruding outward to form an annular radial sealing rib; the shock-absorbing rubber washer is fitted onto the outside of the metal shell.

[0020] The beneficial effects of this solution are as follows: The ultrasonic sensor proposed in this solution uses shock-absorbing rubber gaskets, which can achieve the effects of shock absorption and buffering. The thickness of the second sealing part is greater than that of the first sealing part. In low-temperature environments, the impact of vibration is transmitted through the second sealing part. The first sealing part does not provide strong rigid support for the transducer, and the sealing ribs still provide a circumferential sealing effect in the radial direction.

[0021] Preferably, the piezoelectric ceramic, the conductive layer, the first matching layer, and the second matching layer are bonded together with adhesive.

[0022] The beneficial effects of this solution are as follows: The ultrasonic sensor proposed in this solution is made by bonding the piezoelectric ceramic, conductive layer, first matching layer and second matching layer with adhesive. This can effectively buffer and absorb the thermal stress caused by the mismatch of the thermal expansion coefficients of the materials in each layer, as well as the mechanical vibration stress during operation, while also ensuring the consistency of the transducer performance.

[0023] Preferably, N protrusions are evenly distributed along the axial direction on the circumferential edge of the first matching layer.

[0024] The beneficial effects of this solution: The ultrasonic sensor proposed in this solution has multiple protrusions distributed around the circumference of the first matching layer, which can isolate the ceramic negative electrode from the outer shell and play an insulating role.

[0025] An ultrasonic metering module includes the ultrasonic sensor described in any one of the above claims.

[0026] The beneficial effects of this solution are as follows: By adopting sensors with electromagnetic shielding, high sealing performance and low temperature adaptability, this solution improves measurement accuracy and anti-interference ability compared with existing technologies, extends the service life of the module, expands the application range of the module, and also reduces maintenance costs.

[0027] An ultrasonic gas meter includes the ultrasonic sensor described in any one of the above claims.

[0028] The beneficial effects of this solution are as follows: The ultrasonic gas meter proposed in this solution uses a metal cover plate and a metal shell for the sensor housing, which can effectively resist electromagnetic interference to the signal. The internal sealing structure can reduce the influence of corrosive gases and water vapor on the sensor, thereby improving the performance and service life of the gas meter. The design of the shock-absorbing rubber gasket can expand the operating temperature range of the gas meter. Attached Figure Description

[0029] The following drawings, which are incorporated herein by reference as part of this invention, are provided for understanding the invention. The drawings illustrate embodiments of the invention and their descriptions, serving to explain the principles of the invention.

[0030] In the attached image:

[0031] Figure 1 An exploded top view of an ultrasonic sensor provided by this utility model;

[0032] Figure 2 An exploded bottom view of an ultrasonic sensor provided by this utility model;

[0033] Figure 3 A schematic diagram of the metal housing of an ultrasonic sensor provided by this utility model;

[0034] Figure 4 This is a schematic diagram of the ultrasonic sensor installed on the metering module.

[0035] Figure 5 This is a magnified view of the ultrasonic sensor mounted on the metering module.

[0036] Figure 6 This is a perspective view of the ultrasonic sensor proposed in this utility model installed on a metering module.

[0037] In the picture:

[0038] 1. Shell 2. Piezoelectric ceramic 3. Conductive layer

[0039] 4. First matching layer; 5. Second matching layer; 6. Metal cover plate

[0040] 7. Metal outer casing 7-1, flange portion 7-2, cylindrical portion

[0041] 7-1-1, First step; 7-1-2, Second step; 7-1-3, Petal-shaped protrusions

[0042] 8. Elastic sealing ring; 9. Elastic sealing gasket; 10. Shock-absorbing rubber gasket.

[0043] 10-1, First sealing part; 10-2, Second sealing part; 10-3, Radial sealing rib.

[0044] 11. Protrusion; 12. Wire; 13. Transducer clip.

[0045] 14. Flow channel 15. Circuit board Detailed Implementation

[0046] In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention can be practiced without one or more of these details. In other instances, certain technical features well-known in the art have not been described in order to avoid confusion with the present invention.

[0047] To fully understand this invention, a detailed description will be provided below. Obviously, the implementation of this invention is not limited to the specific details familiar to those skilled in the art. Preferred embodiments of this invention are described in detail below; however, other embodiments may also be possible besides these detailed descriptions.

[0048] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to the present invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of the stated features, integrals, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or combinations thereof.

[0049] The ordinal numbers such as "first" and "second" used in this invention are merely identifiers and have no other meaning, such as a specific order. Furthermore, for example, the term "first component" does not imply the existence of "second component," and the term "second component" does not imply the existence of "first component."

[0050] It should be noted that the terms “up,” “down,” “front,” “back,” “left,” “right,” “inner,” “outer,” and similar expressions used in this article are for illustrative purposes only and are not intended to be restrictive.

[0051] Exemplary embodiments of the present invention will now be described in more detail with reference to the accompanying drawings. However, these exemplary embodiments may be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein. It should be understood that these embodiments are provided so that the disclosure of the present invention is thorough and complete, and that the concept of these exemplary embodiments is fully conveyed to those skilled in the art.

[0052] Example 1

[0053] Figure 1 and Figure 2 These are exploded top and bottom views of an ultrasonic sensor provided by this utility model. An ultrasonic sensor includes: a housing 1, a piezoelectric ceramic 2, a conductive layer 3, a first matching layer 4, and a second matching layer 5. The housing 1 includes a metal cover plate 6 and a metal outer shell 7. The bottom of the metal outer shell 7 is hollowed out. The first matching layer 4 is bonded to the bottom of the metal outer shell 7 using an adhesive coating process. During processing, the metal cover plate 6 and the metal outer shell 7 are integrally injection molded. The first matching layer 4 is injection molded onto the metal outer shell 7 to achieve integral molding. The piezoelectric ceramic 2, conductive layer 3, first matching layer 4, and second matching layer 5 are stacked sequentially. For ease of assembly, the conductive layer 3 is designed as a circular disc, and the piezoelectric ceramic 2 is designed as a cuboid. The piezoelectric ceramic 2 is fixed to the conductive layer 3, preferably a steel sheet. Then, the piezoelectric ceramic 2 and the conductive layer 3 are fixed to the inner surface of the first matching layer 4, which has already been injection molded onto the housing 1. The second matching layer 5 is fixed to the outer surface of the first matching layer 4. The piezoelectric ceramic 2 and the conductive layer 3 serve as positive and negative electrodes, respectively connected to wires 12, preferably by welding.

[0054] Figure 3 This is a schematic diagram of the metal housing of an ultrasonic sensor provided by the present invention. The metal housing 7 has a radially extending flange portion 7-1 and an axially extending cylindrical portion 7-2. The flange portion 7-1 is stepped, including a first step 7-1-1 and a second step 7-1-2. The outer diameter of the first step 7-1-1 is larger than the outer diameter of the second step 7-1-2. The first step 7-1-1 is higher than the second step 7-1-2 in the axial direction. The first step 7-1-1 and the second step 7-1-2 are connected by a radially extending stepped surface. The outer edge of the first step 7-1-1 has equally spaced petal-shaped protrusions 7-1-3.

[0055] The outer edge of the metal cover plate 6 has claws 6-1 arranged at equal intervals along the axial direction.

[0056] The petal-shaped protrusions 7-1-3 and the claws 6-1 are arranged alternately and fixed by mechanical riveting.

[0057] During assembly, the metal cover plate 6 is placed on the metal shell 7, and the petal-shaped protrusions 7-1-3 and the claws 6-1 engage and limit the movement. Then, the claws 6-1 are pressed flat by the cover fixture to achieve the functions of fixation and mechanical sealing.

[0058] The ultrasonic sensor proposed in this embodiment has a metal housing. The metal cover and the metal outer shell are fixed by mechanical riveting to form an effective electromagnetic shielding cavity, which protects the internal functional components and effectively resists electromagnetic interference.

[0059] Example 2

[0060] An ultrasonic sensor includes: a housing 1, a piezoelectric ceramic 2, a conductive layer 3, a first matching layer 4, and a second matching layer 5. The housing 1 includes a metal cover plate 6 and a metal outer shell 7. The bottom of the metal outer shell 7 is hollowed out. The first matching layer 4 is bonded to the bottom of the metal outer shell 7 by an adhesive coating process. During processing, the metal cover plate 6 and the metal outer shell 7 are integrally injection molded. The first matching layer 4 is injection molded onto the metal outer shell 7 to achieve the purpose of integral molding. The piezoelectric ceramic 2, conductive layer 3, first matching layer 4, and second matching layer 5 are stacked sequentially. For ease of assembly, the conductive layer 3 is designed as a circular sheet, and the piezoelectric ceramic 2 is designed as a cuboid. The piezoelectric ceramic 2 is fixed on the conductive layer 3, preferably a steel sheet. Then, the piezoelectric ceramic 2 and the conductive layer 3 are fixed to the inner surface of the first matching layer 4, which has been injection molded onto the housing 1. The second matching layer 5 is fixed to the outer surface of the first matching layer 4. The piezoelectric ceramic 2 and the conductive layer 3 serve as positive and negative electrodes and are connected to wires 12, preferably by welding.

[0061] The metal casing 7 has a radially extending flange portion 7-1 and an axially extending cylindrical portion 7-2; the flange portion 7-1 is stepped, including a first step 7-1-1 and a second step 7-1-2, the outer diameter of the first step 7-1-1 is larger than the outer diameter of the second step 7-1-2, the first step 7-1-1 is higher than the second step 7-1-2 in the axial direction, and the first step 7-1-1 and the second step 7-1-2 are connected by a radially extending stepped surface; the outer edge of the first step 7-1-1 has equally spaced petal-shaped protrusions 7-1-3.

[0062] like Figure 1 and Figure 2As shown, the conductor 12 is an FPC wire, and the grounding end of the FPC wire is welded to the flange of the metal casing. The positive end of the FPC wire is welded to the piezoelectric ceramic 2, the negative end is welded to the conductive layer 3, and the grounding end is welded to the second step 7-1-2 or the petal-shaped protrusion 7-1-3 of the flange of the metal casing 7, which serves as a grounding function. The second step 7-1-2 is higher than the first step 7-1-1 in the axial direction, which provides support for the FPC wire.

[0063] In this embodiment, the conductor 12 is an FPC wire. The design of the FPC wire itself can provide electromagnetic shielding, so the entire transducer has the function of electromagnetic shielding.

[0064] Example 3

[0065] An ultrasonic sensor includes: a housing 1, a piezoelectric ceramic 2, a conductive layer 3, a first matching layer 4, and a second matching layer 5. The housing 1 includes a metal cover plate 6 and a metal outer shell 7. The bottom of the metal outer shell 7 is hollowed out. The first matching layer 4 is bonded to the bottom of the metal outer shell 7 by an adhesive coating process. During processing, the metal cover plate 6 and the metal outer shell 7 are integrally injection molded. The first matching layer 4 is injection molded onto the metal outer shell 7 to achieve the purpose of integral molding. The piezoelectric ceramic 2, conductive layer 3, first matching layer 4, and second matching layer 5 are stacked sequentially. For ease of assembly, the conductive layer 3 is designed as a circular sheet, and the piezoelectric ceramic 2 is designed as a cuboid. The piezoelectric ceramic 2 is fixed on the conductive layer 3, preferably a steel sheet. Then, the piezoelectric ceramic 2 and the conductive layer 3 are fixed to the inner surface of the first matching layer 4, which has been injection molded onto the housing 1. The second matching layer 5 is fixed to the outer surface of the first matching layer 4. The piezoelectric ceramic 2 and the conductive layer 3 serve as positive and negative electrodes and are respectively connected to wires 12.

[0066] The metal casing 7 has a radially extending flange portion 7-1 and an axially extending cylindrical portion 7-2; the flange portion 7-1 is stepped, including a first step 7-1-1 and a second step 7-1-2, the outer diameter of the first step 7-1-1 is larger than the outer diameter of the second step 7-1-2, the first step 7-1-1 is higher than the second step 7-1-2 in the axial direction, and the first step 7-1-1 and the second step 7-1-2 are connected by a radially extending stepped surface; the outer edge of the first step 7-1-1 has equally spaced petal-shaped protrusions 7-1-3.

[0067] like Figure 1 and Figure 2As shown, it also includes an elastic sealing ring 8 and an elastic sealing gasket 9. The cross-section of the elastic sealing ring 8 is stepped, including a radially extending limiting part 8-1 and an axially extending limiting part 8-2. The radially extending limiting part 8-1 includes an annular protrusion, an annular groove and another annular protrusion. The annular groove is located between the two annular protrusions.

[0068] This embodiment further strengthens the sealing measures through the elastic sealing ring 8 and the elastic sealing gasket 9. The structural design of the elastic sealing ring 8 matches the structural design of the metal shell 7. The radially extending limiting part 8-1 of the elastic sealing ring 8 covers the second step 7-1-2 of the metal shell 7, and the axially extending limiting part 8-8 is nested in the cylindrical part 7-2 of the metal shell 7. The elastic sealing gasket 9 covers the elastic sealing ring 8, which plays a further sealing role and can prevent corrosive substances and moisture from entering the transducer and causing irreparable damage to the transducer.

[0069] Example 4

[0070] An ultrasonic sensor includes: a housing 1, a piezoelectric ceramic 2, a conductive layer 3, a first matching layer 4, and a second matching layer 5. The housing 1 includes a metal cover plate 6 and a metal outer shell 7. The bottom of the metal outer shell 7 is hollowed out. The first matching layer 4 is bonded to the bottom of the metal outer shell 7 by an adhesive coating process. During processing, the metal cover plate 6 and the metal outer shell 7 are integrally injection molded. The first matching layer 4 is injection molded onto the metal outer shell 7 to achieve the purpose of integral molding. The piezoelectric ceramic 2, conductive layer 3, first matching layer 4, and second matching layer 5 are stacked sequentially. For ease of assembly, the conductive layer 3 is designed as a circular sheet, and the piezoelectric ceramic 2 is designed as a cuboid. The piezoelectric ceramic 2 is fixed on the conductive layer 3, preferably a steel sheet. Then, the piezoelectric ceramic 2 and the conductive layer 3 are fixed to the inner surface of the first matching layer 4, which has been injection molded onto the housing 1. The second matching layer 5 is fixed to the outer surface of the first matching layer 4. The piezoelectric ceramic 2 and the conductive layer 3 serve as positive and negative electrodes and are respectively connected to wires 12.

[0071] The metal casing 7 has a radially extending flange portion 7-1 and an axially extending cylindrical portion 7-2; the flange portion 7-1 is stepped, including a first step 7-1-1 and a second step 7-1-2, the outer diameter of the first step 7-1-1 is larger than the outer diameter of the second step 7-1-2, the first step 7-1-1 is higher than the second step 7-1-2 in the axial direction, and the first step 7-1-1 and the second step 7-1-2 are connected by a radially extending stepped surface; the outer edge of the first step 7-1-1 has equally spaced petal-shaped protrusions 7-1-3.

[0072] like Figure 1 and Figure 2As shown, this solution also includes a shock-absorbing rubber washer 10, which includes a first sealing part 10-1 on the radially inner side and a second sealing part 10-2 on the radially outer side. The axial thickness of the second sealing part 10-2 is greater than the axial thickness of the first sealing part 10-1. The lower surface of the second sealing part 10-2 is provided with a downwardly protruding axial sealing protrusion. The outer periphery of the second sealing part is radially protruding outward to form an annular radial sealing rib 10-3. The shock-absorbing rubber washer 10 is disposed outside the metal shell 7.

[0073] In this scheme, the structural design of the shock-absorbing rubber gasket 10 is closely related to the structural design of the metal shell 7. The first sealing part 10-1 of the shock-absorbing rubber gasket 10 is in contact with the outer surface of the second step 7-1-2 of the metal shell 7, and the first step 7-1-1 is in contact with the second sealing part 10-2.

[0074] Figure 4 and Figure 5 The figures show an overall schematic diagram and a magnified view of the ultrasonic sensor mounted on the metering module. When the ultrasonic sensor is subjected to vibration, the axial sealing protrusion on the lower surface of the second sealing part 10-2 receives the transmitted force. Similarly, in low-temperature environments, the shock-absorbing rubber gasket 10 is easily hardened due to temperature effects. The second sealing part 10-2 only makes hard contact with a part of the sensor structure and does not affect the entire structure. Therefore, the performance of the sensor is not affected.

[0075] Example 5

[0076] An ultrasonic sensor includes: a housing 1, a piezoelectric ceramic 2, a conductive layer 3, a first matching layer 4, and a second matching layer 5. The housing 1 includes a metal cover plate 6 and a metal outer shell 7. The bottom of the metal outer shell 7 is hollowed out. The first matching layer 4 is bonded to the bottom of the metal outer shell 7 by an adhesive coating process. During processing, the metal cover plate 6 and the metal outer shell 7 are integrally injection molded. The first matching layer 4 is injection molded onto the metal outer shell 7 to achieve the purpose of integral molding. The piezoelectric ceramic 2, the conductive layer 3, the first matching layer 4, and the second matching layer 5 are stacked sequentially and bonded to each other with adhesive. The adhesive can be a quick-drying adhesive or an epoxy adhesive. For ease of assembly, the conductive layer 3 is designed as a circular sheet, and the piezoelectric ceramic 2 is designed as a cuboid. The piezoelectric ceramic 2 is fixed on the conductive layer 3, preferably a steel sheet. Then, the piezoelectric ceramic 2 and the conductive layer 3 are fixed to the inner surface of the first matching layer 4, which has been injection molded onto the housing 1, and the second matching layer 5 is fixed to the outer surface of the first matching layer 4. The piezoelectric ceramic 2 and the conductive layer 3 serve as positive and negative electrodes, respectively, and are connected to the wire 12.

[0077] The proposed ultrasonic sensor uses a piezoelectric ceramic, a conductive layer, a first matching layer, and a second matching layer bonded together with adhesive. This effectively buffers and absorbs thermal stress caused by the mismatch in the thermal expansion coefficients of the materials in each layer, as well as mechanical vibration stress during operation, while also ensuring the consistency of the transducer's performance.

[0078] Example 6

[0079] An ultrasonic sensor includes: a housing 1, a piezoelectric ceramic 2, a conductive layer 3, a first matching layer 4, and a second matching layer 5. The housing 1 includes a metal cover plate 6 and a metal outer shell 7. The bottom of the metal outer shell 7 is hollowed out. The first matching layer 4 is bonded to the bottom of the metal outer shell 7 by an adhesive coating process. During processing, the metal cover plate 6 and the metal outer shell 7 are integrally injection molded. The first matching layer 4 is injection molded onto the metal outer shell 7 to achieve the purpose of integral molding. The piezoelectric ceramic 2, conductive layer 3, first matching layer 4, and second matching layer 5 are stacked sequentially. For ease of assembly, the conductive layer 3 is designed as a circular sheet, and the piezoelectric ceramic 2 is designed as a cuboid. The piezoelectric ceramic 2 is fixed on the conductive layer 3, preferably a steel sheet. Then, the piezoelectric ceramic 2 and the conductive layer 3 are fixed to the inner surface of the first matching layer 4, which has been injection molded onto the housing 1. The second matching layer 5 is fixed to the outer surface of the first matching layer 4. The piezoelectric ceramic 2 and the conductive layer 3 serve as positive and negative electrodes and are respectively connected to wires 12.

[0080] like Figure 3 As shown, N protrusions 11 are evenly distributed along the axial direction on the circumferential edge of the first matching layer 4. The material of the protrusions 11 is the same as that of the first matching layer 4, but other non-conductive materials can also be used. These protrusions 11 can isolate the ceramic negative electrode from the outer shell, thus providing insulation. The first matching layer is preferably made of PPS material, but other materials can be selected according to actual needs. The advantage of this is that, as the negative electrode, the conductive layer 3 will not come into contact with the metal outer shell 7 in the finished product. At the same time, in some designs, the grounding terminal of the wire 12 is soldered to the metal outer shell 7, so the grounding terminal will not be connected to the negative electrode, ensuring the safety of the product.

[0081] Example 7

[0082] An ultrasonic metering module includes the ultrasonic sensors described in Embodiments 1 to 6. Figures 4-6As shown, in this embodiment, the ultrasonic sensor is a transducer, which is installed on the flow channel 14. Two transducers are installed on the flow channel in this embodiment, one for emitting ultrasonic waves and the other for receiving ultrasonic waves. A transducer clip 13 is installed on the upper end of the transducer to fix the transducer. The wire 12 is an FPC wire. The FPC wire outlet is left on the flange 7-1 of the metal shell 7. The FPC wire is fixed to the circuit board 15 by a pin, thereby realizing the transmission and reception of electrical signals and further processing.

[0083] This solution, by employing sensors with electromagnetic shielding, high sealing performance, and low-temperature adaptability, improves measurement accuracy and anti-interference capabilities compared to existing technologies, extends the module's service life, expands the module's application range, and also reduces maintenance costs.

[0084] Example 8

[0085] An ultrasonic gas meter includes the ultrasonic sensor described in Embodiments 1 to 6, and also includes the ultrasonic metering module described in Embodiment 7.

[0086] This solution proposes an ultrasonic gas meter with a sensor housing made of a metal cover and a metal outer shell, which can effectively resist electromagnetic interference to the signal. The internal sealing structure can reduce the influence of corrosive gases and water vapor on the sensor, thereby improving the performance and service life of the gas meter. The design of the shock-absorbing rubber gasket can expand the operating temperature range of the gas meter.

[0087] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments. Many other equivalent embodiments may be included without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. An ultrasonic sensor, characterized in that, include: The shell, piezoelectric ceramic, conductive layer, first matching layer and second matching layer; The housing includes a metal cover plate and a metal outer shell, with the bottom of the metal outer shell being hollowed out; The piezoelectric ceramic, conductive layer, first matching layer and second matching layer are stacked sequentially. The first matching layer is bonded to the bottom of the metal shell by an adhesive coating process. The piezoelectric ceramic and conductive layer serve as positive and negative electrodes and are respectively connected to the wires.

2. An ultrasonic sensor according to claim 1, characterized in that, The metal casing has a radially extending flange portion and an axially extending cylindrical portion; the flange portion is stepped, including a first step and a second step, the outer diameter of the first step is larger than the outer diameter of the second step, the first step is higher than the second step in the axial direction, and the first step and the second step are connected by a radially extending step surface; the outer edge of the first step has petal-shaped protrusions arranged at equal intervals.

3. An ultrasonic sensor according to claim 2, characterized in that, The outer edge of the metal cover plate has claws arranged at equal intervals along the axial direction.

4. An ultrasonic sensor according to claim 3, characterized in that, The petal-shaped protrusions and claws are arranged in an alternating pattern and fixed by mechanical riveting.

5. An ultrasonic sensor according to claim 2, characterized in that, The conductor is an FPC wire, and the grounding end of the FPC wire is soldered to the flange of the metal casing.

6. An ultrasonic sensor according to claim 2, characterized in that, It also includes an elastic sealing ring, the cross-section of which is stepped, including a radially extending limiting portion and an axially extending limiting portion; the radially extending limiting portion includes an annular protrusion, an annular groove and another annular protrusion; the annular groove is located between the two annular protrusions.

7. An ultrasonic sensor according to claim 6, characterized in that, The elastic sealing ring is nested in the metal shell.

8. An ultrasonic sensor according to claim 7, characterized in that, It also includes an elastic sealing gasket that covers the elastic sealing ring.

9. An ultrasonic sensor according to claim 2, characterized in that, It also includes a shock-absorbing rubber gasket, which includes a first sealing part on the radially inner side and a second sealing part on the radially outer side. The axial thickness of the second sealing part is greater than the axial thickness of the first sealing part. The lower surface of the second sealing part is provided with a downwardly protruding axial sealing protrusion. The periphery of the second sealing part protrudes radially outward to form an annular radial sealing rib. The shock-absorbing rubber gasket is fitted onto the outside of the metal shell.

10. An ultrasonic sensor according to claim 1, characterized in that, The piezoelectric ceramic, conductive layer, first matching layer and second matching layer are bonded together with adhesive.

11. An ultrasonic sensor according to claim 1, characterized in that, The first matching layer has N protrusions evenly distributed along the axial direction on its circumferential edge.

12. An ultrasonic metering module, characterized in that, Includes the ultrasonic sensor as described in any one of claims 1 to 11.

13. An ultrasonic gas meter, characterized in that, Includes the ultrasonic sensor as described in any one of claims 1 to 11.

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