Low-frequency double-layer vector hydrophone with flexoelectric and piezoelectric effects and its manufacturing method

Abstract

The present invention relates to the field of sensing technology and discloses a low-frequency double-layer vector hydrophone with flexoelectric and piezoelectric effects and a method for manufacturing the device. The device comprises a double-layer piezoelectric ceramic assembly, a fixture, two wires, and a rubber housing. The fixture comprises a pressure plate and a pressure block. The pressure plate is a circular ring structure. One end of the double-layer piezoelectric ceramic assembly is placed on a clamping portion, and the double-layer piezoelectric ceramic assembly is clamped on the clamping portion by the pressure block, forming a cantilever beam structure. Two wires are respectively arranged between the double-layer piezoelectric ceramic assembly, the clamping portion, and the pressure block. The pressure plate is fixedly mounted within the rubber housing, which is filled with castor oil. The other ends of the two wires extend through the rubber housing and are respectively connected to the outside of the housing and connected to the electrode terminals. The hydrophone can more effectively capture low-frequency sound wave signals. The double-layer structure combines the flexoelectric and piezoelectric effects, enabling it to generate a stronger electrical signal output under the same external sound wave excitation, thereby improving the detection sensitivity of low-frequency sound waves.

Description

Technical Field

[0001] The present invention relates to the field of sensing technology, and in particular to a low-frequency double-layer vector hydrophone with flexoelectric and piezoelectric effects and a manufacturing method thereof. Background Art

[0002] In the field of ocean exploration, many countries are committed to developing underwater acoustic detection technology to enhance the sonar detection and combat capabilities of ships. Hydrophones, a key component of sonar, are used to receive underwater acoustic signals and are widely used for underwater communications, target positioning, and tracking. Due to the physical limitations of seawater on sound wave propagation, high-frequency sound waves are converted to low-frequency sound waves when propagating from the far field. Compared to scalar hydrophones, vector hydrophones are specialized underwater sensors designed specifically for measuring underwater acoustic signals, and are particularly suitable for low-frequency sound waves. Unlike scalar hydrophones, which measure signal amplitude, vector hydrophones can measure both the magnitude and direction of underwater sound. Therefore, vector hydrophones can determine the complete sound velocity vector, providing a more complete and accurate representation of the underwater sound field.

[0003] Currently, common vector hydrophones include piezoresistive hydrophones, capacitive hydrophones, piezoelectric hydrophones, and flexoelectric hydrophones. Compared to piezoresistive and capacitive hydrophones, piezoelectric and flexoelectric hydrophones are passive hydrophones. Piezoresistive hydrophones have low transduction efficiency, while capacitive hydrophones are susceptible to parasitic capacitance. Piezoelectric hydrophones offer the advantages of low cost and high stability, but they cannot directly measure vector signals such as pressure gradients. Flexoelectric hydrophones have the ability to directly measure vector signals such as pressure gradients, but this effect is limited by their relatively low flexoelectric coefficient, which may affect the sensitivity of the hydrophone. Therefore, a compromise solution to enhance the flexoelectric effect has been proposed, namely the quasi-flexoelectric effect. The quasi-flexoelectric effect has a similar electromechanical coupling effect to flexoelectrics. The principle of the quasi-flexoelectric effect is to enhance the effective flexoelectric coefficient in any possible way. Compared with other types of flexural effects, it is particularly important to design a high-sensitivity low-frequency hydrophone that can directly measure vector signals by combining the advantages of piezoelectric effect and flexoelectric effect. Summary of the Invention

[0004] In order to overcome the defects of the above-mentioned prior art, the purpose of the present invention is to provide a low-frequency double-layer vector hydrophone with flexoelectric and piezoelectric effects and a manufacturing method, so as to solve the technical problems in the prior art of how to improve the sensitivity performance of the hydrophone and directly measure the vector signal.

[0005] The present invention is achieved through the following technical solutions:

[0006] In a first aspect, the present invention provides a low-frequency double-layer vector hydrophone with flexoelectric and piezoelectric effects, comprising a double-layer piezoelectric ceramic component, a fixture, two wires, and a rubber shell;

[0007] The clamp includes a pressing plate and a pressing block; the pressing plate is in a circular ring structure; and a clamping portion is extended from the inner side wall;

[0008] One end of the double-layer piezoelectric ceramic component is placed on the clamping portion, and the double-layer piezoelectric ceramic component is clamped on the clamping portion by a pressing block to form a cantilever beam structure;

[0009] Two wires are respectively arranged between the double-layer piezoelectric ceramic component and the clamping portion and the pressing block, wherein the end of one wire is clamped between the bottom surface of the double-layer piezoelectric ceramic component and the top surface of the clamping portion; the end of the other wire is clamped between the top surface of the double-layer piezoelectric ceramic component and the bottom surface of the pressing block;

[0010] The pressing plate is fixedly arranged in a rubber shell filled with castor oil. The other ends of the two wires pass through the rubber shell and extend to the outside to be connected to the electrode ends.

[0011] Preferably, the double-layer piezoelectric ceramic component includes a first piezoelectric ceramic sheet and a second piezoelectric ceramic sheet; the first piezoelectric ceramic sheet and the second piezoelectric ceramic sheet are bonded relative to each other.

[0012] Furthermore, the first piezoelectric ceramic piece and the second piezoelectric ceramic piece are equal in size.

[0013] Preferably, two groups of connecting holes are provided on the clamping part and the pressing block respectively, and the two groups of connecting holes are respectively threaded with a first bolt assembly. The pressing block cover is provided at one end of the double-layer piezoelectric ceramic assembly, and the pressing block is pressed onto the clamping part by the first bolt assembly.

[0014] Preferably, the diameter of the inner ring of the pressure plate is greater than the length of the double-layer piezoelectric ceramic component.

[0015] Preferably, the rubber housing includes a first housing and a second housing;

[0016] The first shell and the second shell are both hollow hemispherical shells; the first shell and the second shell are relatively connected; the pressure plate is clamped between the first shell and the second shell;

[0017] The pressure plate is annularly fixed on the mounting rings of the first shell and the second shell.

[0018] Furthermore, a plurality of fixing holes are provided on the mounting rings of the pressure plate, the first shell and the second shell in a corresponding circumferential direction;

[0019] A plurality of second bolt assemblies are respectively threadedly connected in the plurality of fixing holes, and the pressure plate is annularly fixed to the mounting rings of the first shell and the second shell through the plurality of second bolt assemblies.

[0020] Furthermore, a through hole is provided on the shell wall of the first shell, which is used to fill castor oil into the first shell and the second shell through the through hole; the other ends of the two wires extend to the outside through the through holes and are connected to the electrode ends.

[0021] Furthermore, after the first shell and the second shell are filled with castor oil, the through hole is sealed with epoxy resin.

[0022] In a second aspect, the present invention further provides a method for manufacturing a low-frequency double-layer vector hydrophone having flexoelectric and piezoelectric effects, which is used to obtain the low-frequency double-layer vector hydrophone having flexoelectric and piezoelectric effects as described above, comprising the following steps:

[0023] Prepare a polarized piezoelectric ceramic sheet, cut it into two rectangular piezoelectric ceramic sheets of the same size using a diamond wire saw, and bond the two piezoelectric ceramic sheets into a whole to obtain a double-layer piezoelectric ceramic assembly;

[0024] A laser engraving machine is used to laser cut the acrylic plate to obtain a pressing plate and a pressing block, and a clamping portion is formed by laser cutting on the inner side of the pressing plate;

[0025] Place one short side of the double-layer piezoelectric ceramic component on the clamping part and clamp it with a pressing block; wherein wires are provided between the upper and lower surfaces of the double-layer piezoelectric ceramic component and the clamping part and the pressing block respectively;

[0026] A layer of copper paint is evenly applied to the inside of the rubber shell to shield electromagnetic interference, and the fixture is fixed inside the rubber shell; the other end of the wire between the upper and lower surfaces of the double-layer piezoelectric ceramic component and the clamping part and the pressure block is led through the rubber shell and connected to the electrode end; castor oil is filled into the rubber shell and the rubber shell is sealed with epoxy resin; thus, the preparation of the low-frequency double-layer vector hydrophone is completed.

[0027] Compared with the prior art, the present invention has the following beneficial technical effects:

[0028] The present invention provides a low-frequency double-layer vector hydrophone with flexoelectric and piezoelectric effects. By adopting a double-layer piezoelectric ceramic component, the hydrophone can more effectively capture low-frequency sound wave signals. The design of the double-layer structure optimizes the piezoelectric effect, so that under the same external sound wave excitation, it can generate a stronger electrical signal output, thereby improving the detection sensitivity of low-frequency sound waves. The present invention utilizes the flexoelectric effect. Under the action of sound waves, the double-layer piezoelectric ceramic component not only undergoes longitudinal compression or tensile deformation, but also produces lateral bending deformation. At the same time, the cantilever beam structure enables the double-layer vector hydrophone to directly measure vector signals. This multi-directional deformation further enhances the power conversion efficiency of the double-layer piezoelectric ceramic component, allowing the hydrophone to respond to sound wave signals more comprehensively, improving the accuracy and precision of the measurement.

[0029] Furthermore, the double-layer piezoelectric ceramic assembly includes a first piezoelectric ceramic sheet and a second piezoelectric ceramic sheet bonded relative to each other. Bonding the two piezoelectric ceramic sheets creates a more robust and stable structure, helping to mitigate performance degradation caused by defects or damage that may exist in a single piezoelectric ceramic sheet. The bonding layer also acts as a buffer and vibration dampener, further enhancing the durability and reliability of the double-layer piezoelectric ceramic assembly.

[0030] Furthermore, the first and second piezoelectric ceramic sheets are of equal size. These equal-sized piezoelectric ceramic sheets distribute stress more evenly when subjected to external forces. This means that within the entire dual-layer piezoelectric ceramic assembly, each part responds similarly to external excitation, reducing the risk of performance degradation or damage due to stress concentration.

[0031] Furthermore, two sets of connection holes are respectively provided on the clamping portion and the pressure block, each of which is threadedly connected to a first bolt assembly. The pressure block cover is provided at one end of the double-layer piezoelectric ceramic assembly, and the pressure block is pressed against the clamping portion by the first bolt assembly. By pressing the pressure block against the clamping portion using the first bolt assembly, the double-layer piezoelectric ceramic assembly is securely clamped. This not only provides sufficient clamping force to prevent the double-layer piezoelectric ceramic assembly from loosening or falling off due to vibration or external forces, but also ensures the stability and reliability of the double-layer piezoelectric ceramic assembly during operation.

[0032] Furthermore, if the diameter of the inner ring of the pressure plate is greater than the length of the double-layer piezoelectric ceramic assembly, the double-layer piezoelectric ceramic assembly will not touch the bottom edge of the pressure plate when clamped, thereby reducing stress concentration and potential damage risks caused by edge contact, increasing the stability of clamping, and ensuring that the double-layer piezoelectric ceramic assembly can maintain its integrity and performance under vibration or external force.

[0033] Furthermore, the rubber housing includes a first shell and a second shell; both are hollow hemispherical shells; the first and second shells are relatively connected; a pressure plate is clamped between the first and second shells; and the pressure plate is annularly fixed to the mounting rings of the first and second shells. By dividing the rubber housing into two hemispherical parts, the first and second shells, and clamping the pressure plate between them, a more rigid and sealed structure is formed. This design not only improves the overall strength of the housing, but also ensures effective protection of internal components, while preventing the intrusion of external moisture, dust, and other contaminants.

[0034] Furthermore, a plurality of fixing holes are circumferentially provided on the pressure plate and the mounting rings of the first shell and the second shell; a plurality of second bolt assemblies are threadedly connected in the plurality of fixing holes, and the pressure plate is circumferentially fixed to the mounting rings of the first shell and the second shell by the plurality of second bolt assemblies. By fixing the pressure plate circumferentially to the mounting rings of the first shell and the second shell by the second bolt assemblies, a firm connection between the pressure plate and the shell can be ensured, which not only improves the stability of the entire structure, but also helps to reduce the risk of loosening or deformation due to vibration or external force.

[0035] Furthermore, the first shell body is provided with a through-hole in the wall for filling the first and second shell bodies with castor oil. The other ends of the two sets of wires extend through the through-holes to connect to the electrode terminals. The through-holes allow operators to easily fill the shells with castor oil. Castor oil, a commonly used acoustic medium, has excellent acoustic and sealing properties, effectively transmitting sound waves and preventing external contaminants from entering the shell. Extending the wires through the through-holes allows for convenient connection to the electrode terminals or other electronic devices. This design allows for a neater arrangement of the wires, reducing the potential risk of failure caused by cluttered wires. It also facilitates subsequent maintenance and replacement.

[0036] Furthermore, after the first and second shells are filled with castor oil, the through-holes are sealed with epoxy resin. Epoxy resin is a high-performance sealing material with excellent adhesion and chemical resistance. Sealing the through-holes with epoxy resin prevents the castor oil from leaking out of the shells and prevents external moisture, dust, or other contaminants from entering the shells.

[0037] The present invention also provides a method for fabricating a low-frequency, double-layer vector hydrophone exhibiting both flexoelectric and piezoelectric effects. Two polarized piezoelectric ceramic sheets are cut into rectangular parallelepipeds of equal size and bonded together to form a single unit, resulting in a high-performance double-layer piezoelectric ceramic assembly. By combining the piezoelectric and flexoelectric effects, the sensitivity and measurement accuracy of the hydrophone are improved. Laser cutting of an acrylic sheet using a laser engraver precisely produces a pressure plate and a pressure block. A clamping portion is formed on the inner side of the pressure plate, ensuring the precision and stability of the fixture, thereby improving the overall performance of the hydrophone. Wires are connected to the clamping portion and the pressure block on the upper and lower surfaces of the double-layer piezoelectric ceramic assembly. These wires are routed through a rubber housing and connected to the electrode terminals, ensuring reliable signal transmission and facilitating subsequent maintenance and testing. A uniform coating of copper paint on the interior of the rubber housing effectively shields electromagnetic interference. Epoxy resin is used to seal the rubber housing, preventing castor oil leakage and external contaminants.

[0038] Furthermore, when an acoustic signal is transmitted to the cantilever beam in the double-layer vector hydrophone, the cantilever beam bends and deforms, with tension applied above the neutral layer and compression applied below the neutral layer. The piezoelectric effect on the upper piezoelectric ceramic sheet of the double-layer vector hydrophone generates a polarization direction from bottom to top. Because the piezoelectric effect is directional, the polarization direction of the lower, reversely bonded piezoelectric ceramic sheet is also from bottom to top. The flexoelectric effect also occurs, and its polarization direction aligns with that generated by the piezoelectric effect. This effectively enhances the flexoelectric effect, significantly improving the output of the hydrophone.

[0039] Furthermore, the dual-layer vector hydrophone of the present invention boasts higher sensitivity than conventional vector hydrophones. Its output is a combination of the piezoelectric and flexoelectric effects, which can be considered a single, effective flexoelectric effect, thus avoiding interference between the two. Furthermore, the dual-layer vector hydrophone, with the same cantilever beam structure as a pressure gradient hydrophone, can directly measure vector signals. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 Schematic diagram of the disassembly of a double-layer piezoelectric ceramic component according to an embodiment of the present invention;

[0041] Figure 2 Schematic diagram of the assembly of a double-layer piezoelectric ceramic component in an embodiment of the present invention;

[0042] Figure 3 Schematic diagram of the disassembly of the clamp in an embodiment of the present invention;

[0043] Figure 4 This is a schematic diagram of the structure of a clamp holding a double-layer piezoelectric ceramic component in an embodiment of the present invention;

[0044] Figure 5 This is a schematic diagram of the disassembly of the rubber housing in an embodiment of the present invention;

[0045] Figure 6 Schematic diagram of the disassembly of a low-frequency double-layer vector hydrophone according to an embodiment of the present invention;

[0046] Figure 7 2. It is an overall schematic diagram of a low-frequency double-layer vector hydrophone according to an embodiment of the present invention;

[0047] Figure 8 is a cross-sectional schematic diagram of a low-frequency double-layer vector hydrophone according to an embodiment of the present invention;

[0048] Figure 9 Schematic diagram of the working principle of a low-frequency double-layer vector hydrophone in an embodiment of the present invention;

[0049] In the figure: 1. Double-layer piezoelectric ceramic assembly; 2. Clamp; 3. Wire; 4. First bolt assembly; 5. Rubber housing; 6. Second bolt assembly; 11. First piezoelectric ceramic sheet; 12. Second piezoelectric ceramic sheet; 21. Pressing plate; 22. Clamping portion; 23. Pressing block; 51. First housing; 52. Through hole; 53. Second housing. DETAILED DESCRIPTION

[0050] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0051] The purpose of the present invention is to provide a low-frequency double-layer vector hydrophone with flexoelectric and piezoelectric effects and a manufacturing method thereof, so as to solve the technical problems in the prior art of how to improve the sensitivity performance of the hydrophone and directly measure vector signals.

[0052] The present invention is described in further detail below with reference to the accompanying drawings:

[0053] Example 1

[0054] See also Figure 6 and Figure 7 In one embodiment of the present invention, a low-frequency double-layer vector hydrophone with flexoelectric and piezoelectric effects is provided, comprising a double-layer piezoelectric ceramic component 1, a fixture 2, two wires 3, and a rubber housing 5; the fixture 2 comprises a pressure plate 21 and a pressure block 23; the pressure plate 21 is a circular ring structure; and a clamping portion 22 is extended from the inner side wall; one end of the double-layer piezoelectric ceramic component 1 is placed on the clamping portion 22, and the double-layer piezoelectric ceramic component 1 is clamped on the clamping portion 22 by the pressure block 23, forming a cantilever beam structure; The two wires 3 are respectively arranged between the double-layer piezoelectric ceramic component 1 and the clamping part 22 and the pressure block 23, wherein the end of one wire 3 is clamped between the bottom surface of the double-layer piezoelectric ceramic component 1 and the top surface of the clamping part 22; the end of the other wire 3 is clamped between the top surface of the double-layer piezoelectric ceramic component 1 and the bottom surface of the pressure block 23; the pressure plate 21 is fixedly arranged in the rubber shell 5, and the rubber shell 5 is filled with castor oil. The other ends of the two wires 3 pass through the rubber shell 5 and extend to the outside to be connected to the electrode end.

[0055] Specifically, according to Figure 1 and Figure 2 As shown, the double-layer piezoelectric ceramic component 1 includes a first piezoelectric ceramic sheet 11 and a second piezoelectric ceramic sheet 12 ; the first piezoelectric ceramic sheet 11 and the second piezoelectric ceramic sheet 12 are bonded relative to each other.

[0056] The first piezoelectric ceramic piece 11 and the second piezoelectric ceramic piece 12 are of equal size.

[0057] In this embodiment, the first piezoelectric ceramic piece 11 and the second piezoelectric ceramic piece 12 are made of PZT-5H piezoelectric ceramic pieces.

[0058] In this embodiment, when an acoustic signal is transmitted to the bilayer piezoelectric ceramic component 1, it bends and deforms. Under the influence of the piezoelectric effect and the flexoelectric effect, charges of opposite polarity are induced on the upper and lower surfaces of the bilayer piezoelectric ceramic component 1, and current is output through the conductor 3. The piezoelectric and flexoelectric effects are the basis for the hydrophone's ability to receive acoustic signals and convert them into electrical signals.

[0059] Specifically, according to Figure 3 and Figure 4 As shown, two groups of connecting holes are respectively provided on the clamping portion 22 and the pressing block 23, and the two groups of connecting holes are respectively threadedly connected with the first bolt assembly 4. The pressing block 23 is covered on one end of the double-layer piezoelectric ceramic component 1, and the pressing block 23 is pressed onto the clamping portion 22 by the first bolt assembly 4.

[0060] Specifically, the diameter of the inner ring of the pressing plate 21 is greater than the length of the double-layer piezoelectric ceramic component 1 .

[0061] In this embodiment, two sets of connection holes are respectively provided on the clamping portion 22 and the pressing block 23. These connection holes are designed so that the first bolt assembly 4 can be threaded into them, thereby pressing the pressing block 23 against the clamping portion 22. This fastening method ensures that one end of the double-layer piezoelectric ceramic component 1 is stably clamped and fixed. The inner ring diameter of the pressure plate 21 is larger than the length of the double-layer piezoelectric ceramic component 1. This design allows a certain amount of space between the clamping portion 22 and the pressing block 23 for the double-layer piezoelectric ceramic component 1, while also ensuring that the double-layer piezoelectric ceramic component 1 can be completely covered and fixed. When sound waves act on the low-frequency double-layer vector hydrophone, the pressure changes generated by the sound waves are transmitted to the double-layer piezoelectric ceramic component 1. Because the double-layer piezoelectric ceramic component 1 is composed of a first piezoelectric ceramic sheet 11 and a second piezoelectric ceramic sheet 12 bonded relative to each other, they will jointly respond to changes in the sound wave pressure. Under the combined action of the piezoelectric effect and the flexoelectric effect, the double-layer piezoelectric ceramic component 1 generates an electric charge, which is transmitted to the electrode end through the wire 3. The changes in these charges represent the intensity and frequency of the sound wave signal, thereby realizing the conversion of the sound wave signal into an electrical signal.

[0062] Specifically, according to Figure 5 As shown, the rubber shell 5 includes a first shell 51 and a second shell 53 ; wherein the rubber shell 5 is made of polyurethane rubber.

[0063] The first shell 51 and the second shell 53 are both hollow hemispherical shells; the first shell 51 and the second shell 53 are relatively connected; the pressure plate 21 is clamped between the first shell 51 and the second shell 53;

[0064] The pressure plate 21 is annularly fixed on the mounting rings of the first shell 51 and the second shell 53 .

[0065] Among them, the pressure plate 21 and the mounting rings of the first shell 51 and the second shell 53 are all provided with a plurality of fixing holes in a corresponding circumferential direction;

[0066] A plurality of second bolt assemblies 6 are threadedly connected in the plurality of fixing holes respectively, and the pressure plate 21 is annularly fixed to the mounting rings of the first shell 51 and the second shell 53 by the plurality of second bolt assemblies 6 .

[0067] A through hole 52 is provided on the shell wall of the first shell 51 for filling castor oil into the first shell 51 and the second shell 53 through the through hole 52 ; the other ends of the two wires 3 extend to the outside through the through holes 52 and are connected to the electrode ends.

[0068] After the first shell 51 and the second shell 53 are filled with castor oil, the through hole 52 is sealed with epoxy resin.

[0069] In this embodiment, when sound waves act on a low-frequency double-layer vector hydrophone, the resulting pressure changes are transmitted to the hydrophone's housing, specifically the first housing 51 and the second housing 53. Because these two housings are relatively connected and together form a complete hollow spherical structure, they can effectively receive sound signals from all directions. The sound signal is further transmitted to the double-layer piezoelectric ceramic assembly 1, which is composed of a first piezoelectric ceramic sheet 11 and a second piezoelectric ceramic sheet 12 bonded relative to each other. Under the influence of the sound wave pressure, the double-layer piezoelectric ceramic assembly 1 generates an electric charge, and this charge change represents the intensity and frequency of the sound wave signal. The charge generated by the double-layer piezoelectric ceramic assembly 1 is transmitted to the electrode terminal via a wire 3. One end of the wire 3 is connected to the upper and lower surfaces of the double-layer piezoelectric ceramic assembly 1, and the other end extends through a through-hole 52 in the first housing 51 to the outside and connect to the electrode terminal. The wire 3 is pre-installed through the through-hole 52 before the castor oil is filled. After the castor oil is filled, the through-hole 52 is sealed with epoxy resin to ensure the airtightness of the housing and prevent the ingress of external contaminants.

[0070] In summary, the present invention provides a low-frequency double-layer vector hydrophone with flexoelectric and piezoelectric effects. By adopting a double-layer piezoelectric ceramic component 1, the hydrophone can more effectively capture low-frequency sound wave signals. The design of the double-layer structure optimizes the piezoelectric effect, so that under the same external sound wave excitation, it can generate a stronger electrical signal output, thereby improving the detection sensitivity of low-frequency sound waves. The present invention utilizes the flexoelectric effect. Under the action of sound waves, the double-layer piezoelectric ceramic component 1 not only undergoes longitudinal compression or tensile deformation, but also produces lateral bending deformation. At the same time, the cantilever beam structure enables the double-layer vector hydrophone to directly measure vector signals. This multi-directional deformation further enhances the power conversion efficiency of the double-layer piezoelectric ceramic component 1, allowing the hydrophone to respond to sound wave signals more comprehensively, improving the accuracy and precision of the measurement.

[0071] Example 2

[0072] This embodiment provides a method for manufacturing a low-frequency double-layer vector hydrophone with flexoelectric and piezoelectric effects, which is used to obtain the low-frequency double-layer vector hydrophone with flexoelectric and piezoelectric effects described above, including the following steps:

[0073] Prepare a polarized 25mm×20mm×1mm PZT-5H piezoelectric ceramic sheet and cut it into two small rectangular PZT-5H piezoelectric ceramic sheets with the dimensions of 25mm×10mm×1mm using an STX-202A diamond wire cutting machine, namely the first piezoelectric ceramic sheet 11 and the second piezoelectric ceramic sheet 12. Figure 1 As shown;

[0074] Polish the negative electrodes of the first piezoelectric ceramic sheet 11 and the second piezoelectric ceramic sheet 12 using a metallographic sample grinding and polishing machine, and adjust the speed of the grinding and polishing machine to 50r / min. After the polished surfaces of the first piezoelectric ceramic sheet 11 and the second piezoelectric ceramic sheet 12 are polished to a clear and bright finish, wipe them with anhydrous alcohol. After the alcohol dries naturally, drip two drops of ceramic glue on the polished surface of the negative electrode of the first piezoelectric ceramic sheet 11, and completely overlap the polished surface of the negative electrode of the second piezoelectric ceramic sheet 12 on the first piezoelectric ceramic sheet 11, so that the first piezoelectric ceramic sheet 11 and the second piezoelectric ceramic sheet 12 are bonded into a whole - a double-layer piezoelectric ceramic assembly 1. The size of the double-layer piezoelectric ceramic assembly 1 is 25mm×10mm×2mm. Figure 2 shown.

[0075] The material of fixture 2 is 3mm thick acrylic plate. A laser engraving machine is used to cut the 3mm thick acrylic plate. The laser tube power is 80W, the cutting power is set to 45%, and the cutting speed is set to 20. Figure 3As shown, the clamp 2 is divided into a pressure plate 21 and a pressure block 23. The pressure block 23 is a small rectangular parallelepiped with a size of 28mm×5mm×3mm. Two connecting holes with a diameter of 1mm and a center distance of 18mm are symmetrically provided along the length direction of the pressure block 23. The centers of the connecting holes are on the perpendicular bisector of the pressure block 23 along the width direction. The pressure plate 21 is annular as a whole, with an outer ring diameter of 71mm and an inner ring diameter of 51mm. The inner ring has a clamping portion 22 with a length of 28mm and a width of 5mm extending along the center direction. Two connecting holes with a diameter of 1mm and a center distance of 18mm are also symmetrically provided along the length direction of the clamping portion 22. The centers of the connecting holes are on the perpendicular bisector of the clamping portion 22 along the width direction. 4mm away from the edge of the outer ring of the pressure plate 21, fixing holes with a diameter of 4mm are evenly provided along the circumference of the ring, as shown Figure 3 shown.

[0076] according to Figure 4 As shown, the short side of the bilayer piezoelectric ceramic assembly 1 is placed between the two connection holes on the inner ring clamping portion 22 of the pressure plate 21 of the fixture 2. The pressure block 23 is aligned with the inner ring clamping portion 22 of the pressure plate 21. Two first bolt assemblies 4 are used to fasten the bilayer piezoelectric ceramic assembly 1 between the pressure plate 21 and the pressure block 23 through the connection holes, forming a cantilever beam structure. Wires 3 are provided between the bilayer piezoelectric ceramic assembly 1, the pressure block 23, and the fixed portion of the pressure plate 21.

[0077] according to Figure 5 As shown, the rubber shell 5 of the double-layer vector hydrophone is made of polyurethane rubber and has a thickness of 1 mm. A layer of copper paint is evenly applied to the interior of the rubber shell 5 to effectively shield electromagnetic interference. The rubber shell 5 is divided into a first shell 51 and a second shell 53. The first shell 51 is composed of a circular ring with an outer diameter of 71 mm and an inner diameter of 51 mm, and a hollow hemispherical shell with an inner diameter of 51 mm. Fixing holes with a diameter of 4 mm are uniformly arranged along the circumference of the ring, 4 mm from the outer edge of the first shell 51. The second shell 53 is also composed of a circular ring with an outer diameter of 71 mm and an inner diameter of 51 mm, and a hollow hemispherical shell with an inner diameter of 51 mm. Fixing holes with a diameter of 4 mm are uniformly arranged along the circumference of the ring, 4 mm from the outer edge of the lower shell 9b. A through hole 52 with a diameter of 4 mm is present in the hollow hemispherical shell of the first shell 51.

[0078] The clamp 2 is positioned in the middle of the rubber housing 5. The fixing holes of the first housing 51, the fixing holes of the clamp 2, and the fixing holes of the second housing 53 are aligned simultaneously. The double-layer vector hydrophone is then secured using the second bolt assembly 6. The wire 3 is led out through the through hole 52 of the first housing 51 and castor oil is filled in. Finally, the rubber housing 5 and the through hole 52 are sealed with epoxy resin, completing the assembly of the low-frequency double-layer vector hydrophone. Figure 6 and Figure 7 As shown. Figure 8 Shown is a cross-sectional view of a double-layer PZT-5H vector hydrophone.

[0079] In this embodiment, according to Figure 9 The following is a diagram showing the working principle of a low-frequency double-layer vector hydrophone:

[0080] When an acoustic signal is transmitted to the cantilever beam, the cantilever beam bends and deforms, with tension applied above the neutral layer and compression applied below the neutral layer. In a single-layer vector hydrophone, the polarization direction generated by the piezoelectric effect above the neutral layer is from bottom to top, while the polarization direction generated by the piezoelectric effect below the neutral layer is from top to bottom. The piezoelectric effects cancel each other out, leaving only the flexoelectric effect. In a double-layer vector hydrophone, the polarization direction generated by the piezoelectric effect on the first piezoelectric ceramic sheet 11 is from bottom to top. Because the piezoelectric effect is directional, the polarization direction generated by the piezoelectric effect on the second piezoelectric ceramic sheet 12 in the lower layer, which is bonded in opposite directions, is also from bottom to top. The flexoelectric effect also exists, and its polarization direction is consistent with that generated by the piezoelectric effect, enhancing its effective flexoelectric effect. Therefore, compared to a single-layer cantilever beam, the cantilever beam structure of the double-layer vector hydrophone can have a greater output and higher sensitivity. The output of the double-layer vector hydrophone is a combination of the piezoelectric effect and the flexoelectric effect, which can be considered as an effective flexoelectric effect as a whole. The double-layer vector hydrophone has the same cantilever beam structure as the pressure gradient hydrophone and can directly measure vector signals.

[0081] In summary, the present invention also provides a method for fabricating a low-frequency, double-layer vector hydrophone exhibiting both flexoelectric and piezoelectric effects. By cutting two polarized piezoelectric ceramic sheets into rectangular parallelepipeds of equal size and bonding them together, a high-performance double-layer piezoelectric ceramic assembly 1 is obtained. By combining the piezoelectric and flexoelectric effects, the sensitivity and measurement accuracy of the hydrophone are improved. Laser engraving is performed on an acrylic sheet to precisely produce a pressure plate 21 and a pressure block 23. A clamping portion 22 is formed on the inner side of the pressure plate 21, ensuring the precision and stability of the fixture 2, thereby improving the overall performance of the hydrophone. Wires 3 are provided on the upper and lower surfaces of the double-layer piezoelectric ceramic assembly 1, respectively, connecting the clamping portion 22 and the pressure block 23. These wires 3 are routed through a rubber housing 5 and connected to the electrode terminals, ensuring reliable signal transmission and facilitating subsequent maintenance and testing. A uniform coating of copper paint on the interior of the rubber housing 5 effectively shields electromagnetic interference. The use of epoxy resin to seal the rubber housing 5 can ensure that the castor oil in the housing does not leak and prevent external pollutants from entering.

[0082] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered by the scope of protection of the claims of the present invention.

Claims

1. A low-frequency double-layer vector hydrophone with flexoelectric and piezoelectric effects, characterized in that: It includes a double-layer piezoelectric ceramic component (1), a fixture (2), two wires (3) and a rubber shell (5); The clamp (2) comprises a pressing plate (21) and a pressing block (23); the pressing plate (21) is in a circular ring structure; and a clamping portion (22) is provided extending from the inner side wall; One end of the double-layer piezoelectric ceramic component (1) is placed on the clamping portion (22), and the double-layer piezoelectric ceramic component (1) is clamped on the clamping portion (22) via a pressing block (23) to form a cantilever beam structure; Two wires (3) are respectively arranged between the double-layer piezoelectric ceramic component (1) and the clamping portion (22) and the pressing block (23), wherein the end of one wire (3) is clamped between the bottom surface of the double-layer piezoelectric ceramic component (1) and the top surface of the clamping portion (22); and the end of the other wire (3) is clamped between the top surface of the double-layer piezoelectric ceramic component (1) and the bottom surface of the pressing block (23); The pressing plate (21) is fixedly arranged in the rubber housing (5), the rubber housing (5) is filled with castor oil, and the other ends of the two wires (3) pass through the rubber housing (5) and extend to the outside to be connected to the electrode ends respectively; The double-layer piezoelectric ceramic component (1) comprises a first piezoelectric ceramic sheet (11) and a second piezoelectric ceramic sheet (12); the first piezoelectric ceramic sheet (11) and the second piezoelectric ceramic sheet (12) are bonded relative to each other; The first piezoelectric ceramic sheet (11) and the second piezoelectric ceramic sheet (12) are of equal size; The rubber housing (5) comprises a first housing (51) and a second housing (53); The first shell (51) and the second shell (53) are both hollow hemispherical shells; the first shell (51) and the second shell (53) are relatively connected; the pressing plate (21) is clamped between the first shell (51) and the second shell (53); The pressure plate (21) is annularly fixed on the mounting rings of the first shell (51) and the second shell (53); A through hole (52) is provided on the shell wall of the first shell (51) for filling castor oil into the first shell (51) and the second shell (53) through the through hole (52); the other ends of the two wires (3) extend to the outside through the through holes (52) and are connected to the electrode ends.

2. The low-frequency double-layer vector hydrophone with flexoelectric and piezoelectric effects according to claim 1, characterized in that: The clamping portion (22) and the pressing block (23) are respectively provided with two groups of connection holes, and the two groups of connection holes are respectively threadedly connected with a first bolt assembly (4). The pressing block (23) is covered on one end of the double-layer piezoelectric ceramic assembly (1), and the pressing block (23) is pressed onto the clamping portion (22) by the first bolt assembly (4).

3. The low-frequency double-layer vector hydrophone with flexoelectric and piezoelectric effects according to claim 1, characterized in that: The diameter of the inner circular ring of the pressure plate (21) is greater than the length of the double-layer piezoelectric ceramic component (1).

4. The low-frequency double-layer vector hydrophone with flexoelectric and piezoelectric effects according to claim 1, characterized in that: The pressure plate (21) and the mounting rings of the first shell (51) and the second shell (53) are all provided with a plurality of fixing holes in a corresponding circumferential direction; A plurality of second bolt assemblies (6) are correspondingly threadedly connected in the plurality of fixing holes, and the pressure plate (21) is annularly fixed to the mounting rings of the first shell (51) and the second shell (53) via the plurality of second bolt assemblies (6).

5. The low-frequency double-layer vector hydrophone with flexoelectric and piezoelectric effects according to claim 1, characterized in that: After the first shell (51) and the second shell (53) are filled with castor oil, the through hole (52) is sealed with epoxy resin.

6. A method for manufacturing a low-frequency double-layer vector hydrophone with flexoelectric and piezoelectric effects, characterized in that: The method for obtaining a low-frequency double-layer vector hydrophone having flexoelectric and piezoelectric effects as claimed in any one of claims 1 to 5 comprises the following steps: Prepare a polarized piezoelectric ceramic sheet, cut it into two rectangular piezoelectric ceramic sheets of the same size using a diamond wire saw, and bond the two piezoelectric ceramic sheets into a whole to obtain a double-layer piezoelectric ceramic assembly (1); A laser engraving machine is used to laser cut the acrylic plate to obtain a pressing plate (21) and a pressing block (23), and a clamping portion (22) is formed by laser cutting the inner side of the pressing plate (21); The short side of the double-layer piezoelectric ceramic component (1) is placed on the clamping portion (22) and clamped by the pressing block (23); wherein the upper and lower surfaces of the double-layer piezoelectric ceramic component (1) are provided with wires (3) between the clamping portion (22) and the pressing block (23); A layer of copper paint is evenly coated on the inside of the rubber shell (5) to shield electromagnetic interference, and the clamp (2) is fixed inside the rubber shell (5); the other end of the wire (3) between the upper and lower surfaces of the double-layer piezoelectric ceramic component (1) and the clamping part (22) and the pressure block (23) passes through the rubber shell (5) and is led out to the electrode end; castor oil is filled into the rubber shell (5), and the rubber shell (5) is sealed with epoxy resin; the preparation of the low-frequency double-layer vector hydrophone is completed.

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