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

Abstract

The invention relates to the technical field of sensing, and discloses a low-frequency double-layer vector hydrophone with flexoelectric and piezoelectric effects and a manufacturing method thereof, the low-frequency double-layer vector hydrophone comprises a double-layer piezoelectric ceramic assembly, a clamp, two wires and a rubber shell; the clamp comprises a pressing plate and a pressing block; the pressing plate is of a circular ring structure; one end of the double-layer piezoelectric ceramic component is placed on the clamping part, and the double-layer piezoelectric ceramic component is clamped on the clamping part through the pressing block to form a cantilever beam type structure; the two wires are arranged between the double-layer piezoelectric ceramic assembly and the clamping part and between the double-layer piezoelectric ceramic assembly and the pressing block respectively, the pressing plate is fixedly arranged in the rubber shell, the rubber shell is filled with castor oil, and the other ends of the two wires penetrate through the rubber shell and extend to the outside to be connected to the electrode ends respectively. The hydrophone can more effectively capture low-frequency sound wave signals. The double-layer structure combines flexoelectric and piezoelectric effects, so that stronger electric signal output can be generated under the same external sound wave excitation, and the detection sensitivity of low-frequency sound waves is improved.

Description

Technical Field

[0001] The present invention relates to the field of sensor 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 detection, in order to enhance the sonar detection capability and combat capability of ships, many countries are committed to developing underwater acoustic detection technology. Hydrophones are important components of sonar, used to receive acoustic signals in the water, and are widely used in underwater communications, target positioning, tracking, etc. Due to the physical limitations of seawater on the propagation of sound waves, high-frequency sound waves will become low-frequency sound waves when they propagate from the far field. Compared with scalar hydrophones, vector hydrophones are special underwater sensors designed for measuring hydroacoustic signals, especially for low-frequency sound waves. Unlike scalar hydrophones used to measure signal amplitude, vector hydrophones can measure the size and direction of underwater sound. Therefore, vector hydrophones can determine the complete sound velocity vector and provide a more complete and accurate representation of the underwater sound field.

[0003] At present, the common vector hydrophones mainly include piezoresistive hydrophones, capacitive hydrophones, piezoelectric hydrophones and flexoelectric hydrophones. Compared with piezoresistive hydrophones and capacitive hydrophones, piezoelectric hydrophones and flexoelectric hydrophones are both passive hydrophones, and the piezoresistive hydrophone has a low transducer efficiency, while the capacitive hydrophone is easily affected by parasitic capacitance. Piezoelectric hydrophones have 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 the relatively low flexoelectric coefficient, which may affect the sensitivity performance of the hydrophone. Therefore, a compromise solution to enhance the flexoelectric effect is 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: 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; The clamp comprises 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; 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; 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; The pressing plate is fixedly arranged in a rubber shell, and the rubber shell is filled with castor oil. The other ends of the two wires penetrate the rubber shell and extend to the outside to be connected to the electrode ends.

[0006] Preferably, the double-layer piezoelectric ceramic component comprises 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.

[0007] Furthermore, the first piezoelectric ceramic sheet and the second piezoelectric ceramic sheet are equal in size.

[0008] Preferably, two groups of connection holes are respectively provided on the clamping part and the pressing block, and the two groups of connection holes are respectively threadedly connected with the 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.

[0009] Preferably, the diameter of the inner ring of the pressing plate is greater than the length of the double-layer piezoelectric ceramic component.

[0010] Preferably, the rubber housing includes a first housing and a second housing; 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; The pressure plate is annularly fixed on the mounting rings of the first shell and the second shell.

[0011] Furthermore, a plurality of fixing holes are provided in a circumferential direction on the mounting rings of the pressure plate, the first shell and the second shell; A plurality of second bolt assemblies are respectively threadedly connected in the plurality of fixing holes, and the pressure plate is annularly fixed on the mounting rings of the first shell and the second shell through the plurality of second bolt assemblies.

[0012] 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.

[0013] Furthermore, after the first shell and the second shell are filled with castor oil, epoxy resin is used to seal the through hole.

[0014] In a second aspect, the present invention further 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 as described above, comprising 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 cutting machine, and bond the two piezoelectric ceramic sheets into a whole to obtain a double-layer piezoelectric ceramic assembly; The acrylic plate is laser cut by a laser engraving machine 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; Place one side of the short side of the double-layer piezoelectric ceramic component on the clamping part and clamp it through the pressing block; wherein the upper and lower surfaces of the double-layer piezoelectric ceramic component are provided with wires between the clamping part and the pressing block respectively; A layer of copper paint is evenly applied on 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 pressing block is respectively passed 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; the preparation of the low-frequency double-layer vector hydrophone is completed.

[0015] Compared with the prior art, the present invention has the following beneficial technical effects: 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, a stronger electrical signal output can be generated, 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.

[0016] Furthermore, the double-layer piezoelectric ceramic assembly 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. By bonding the two piezoelectric ceramic sheets, a more solid and stable structure can be formed, which helps to reduce the performance degradation caused by defects or damage that may exist in a single piezoelectric ceramic sheet. At the same time, the bonding layer can also play a role in buffering and vibration reduction, further improving the durability and reliability of the double-layer piezoelectric ceramic assembly.

[0017] Furthermore, the first piezoelectric ceramic sheet and the second piezoelectric ceramic sheet are of equal size, and piezoelectric ceramic sheets of equal size can distribute stress more evenly when subjected to external force. This means that in the entire double-layer piezoelectric ceramic component, each part can respond to external excitation in a similar manner, thereby reducing the risk of performance degradation or damage caused by stress concentration.

[0018] Furthermore, two groups of connection holes are respectively provided on the clamping part and the pressing block, and the first bolt assemblies are respectively threadedly connected in the two groups of connection holes. The pressing block cover is provided at one end of the double-layer piezoelectric ceramic assembly, and the pressing block is pressed against the clamping part by the first bolt assembly. By pressing the pressing block against the clamping part by the first bolt assembly, it can be ensured that the double-layer piezoelectric ceramic assembly is firmly clamped, which not only provides sufficient clamping force to prevent the double-layer piezoelectric ceramic assembly from loosening or falling off under vibration or external force, but also ensures the stability and reliability of the double-layer piezoelectric ceramic assembly during operation.

[0019] Furthermore, if the diameter of the inner ring of the pressure plate is larger 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.

[0020] Furthermore, the rubber shell includes a first shell and a second shell; 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; the pressure plate is annularly fixed on the mounting rings of the first shell and the second shell. By dividing the rubber shell into two hemispherical parts of the first shell and the second shell and clamping the pressure plate between them, a more solid and sealed structure can be formed. This design not only improves the overall strength of the shell, but also ensures the effective protection of the internal components, while preventing the intrusion of external moisture, dust or other pollutants.

[0021] Furthermore, a plurality of fixing holes are circumferentially provided on the mounting rings of the pressure plate and the first shell and the second shell; a plurality of second bolt assemblies are respectively 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.

[0022] 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 groups of wires are respectively extended to the outside through the through holes and connected to the electrode ends. The through hole allows the operator to easily fill the shell with castor oil through it. Castor oil, as a commonly used acoustic medium, has good acoustic and sealing properties, can effectively transmit sound waves and prevent external contaminants from entering the shell. The wire is extended to the outside through the through hole, and can be easily connected to the electrode end or other electronic equipment. This design makes the arrangement of the wires neater and reduces the potential risk of failure caused by the mess of the wires. At the same time, it is also convenient for subsequent maintenance and replacement work.

[0023] Furthermore, after the first shell and the second shell are filled with castor oil, epoxy resin is used to seal the through hole. Epoxy resin is a high-performance sealing material with excellent adhesion and chemical corrosion resistance. Using epoxy resin to seal the through hole can ensure that the castor oil in the shell does not leak, and prevent external moisture, dust or other pollutants from entering the shell.

[0024] The present invention also provides a method for manufacturing a low-frequency double-layer vector hydrophone with flexoelectric and piezoelectric effects. By cutting two polarized piezoelectric ceramic sheets into rectangular blocks of the same size and bonding them into a whole, a high-performance double-layer piezoelectric ceramic component is obtained, and by combining the piezoelectric effect and the flexoelectric effect, the sensitivity and measurement accuracy of the hydrophone are improved. The acrylic plate is laser cut by a laser engraving machine to accurately obtain a pressing plate and a pressing block, and a clamping portion is formed on the inner side of the pressing plate to ensure the accuracy and stability of the fixture, thereby improving the overall performance of the hydrophone. The upper and lower surfaces of the double-layer piezoelectric ceramic component are respectively provided with wires between the clamping portion and the pressing block. These wires are led out through a rubber shell and connected to the electrode end, ensuring reliable signal transmission and facilitating subsequent maintenance and testing. A layer of copper paint is evenly applied to the inside of the rubber shell to effectively shield electromagnetic interference. The rubber shell is sealed with epoxy resin to ensure that the castor oil in the shell will not leak and prevent external pollutants from entering.

[0025] Furthermore, when the acoustic signal is transmitted to the cantilever beam in the double-layer vector hydrophone, the cantilever beam bends and deforms, and the cantilever beam is pulled above the neutral layer and compressed below the neutral layer. The polarization direction of the upper piezoelectric ceramic sheet of the double-layer vector hydrophone generated by the piezoelectric effect is from bottom to top. Since the piezoelectric effect is directional, the polarization direction of the lower reversely bonded piezoelectric ceramic sheet generated by the piezoelectric effect is also from bottom to top. At the same time, there is also a flexoelectric effect. The polarization direction of the flexoelectric effect is consistent with the polarization direction generated by the piezoelectric effect. Its effective flexoelectric effect is enhanced, which significantly improves the output of the hydrophone.

[0026] Furthermore, the double-layer vector hydrophone of the present invention has a higher sensitivity than the traditional vector hydrophone. The output of the double-layer vector hydrophone is a combination of piezoelectric effect and flexoelectric effect, which can be regarded as an effective flexoelectric effect as a whole, and the interference between piezoelectric and flexoelectric can be avoided. At the same time, the double-layer vector hydrophone has the same cantilever beam structure as the sound pressure gradient hydrophone, and can directly measure the vector signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 Schematic diagram of disassembly of a double-layer piezoelectric ceramic component in an embodiment of the present invention; Figure 2 A schematic diagram of the combination of a double-layer piezoelectric ceramic component in an embodiment of the present invention; Figure 3 Schematic diagram of the disassembly of the clamp in the embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of a clamp clamping a double-layer piezoelectric ceramic component in an embodiment of the present invention; Figure 5 This is a schematic diagram of the disassembly of the rubber housing in an embodiment of the present invention; Figure 6 Schematic diagram of the disassembly of a low-frequency double-layer vector hydrophone in an embodiment of the present invention; Figure 7 is an overall schematic diagram of a low-frequency double-layer vector hydrophone in an embodiment of the present invention; Figure 8 is a cross-sectional schematic diagram of a low-frequency double-layer vector hydrophone in an embodiment of the present invention; Fig. 9 Schematic diagram of the working principle of a low-frequency double-layer vector hydrophone in an embodiment of the present invention; In the figure: 1. double-layer piezoelectric ceramic assembly; 2. fixture; 3. wire; 4. first bolt assembly; 5. rubber shell; 6. second bolt assembly; 11. first piezoelectric ceramic sheet; 12. second piezoelectric ceramic sheet; 21. pressure plate; 22. clamping part; 23. pressure block; 51. first shell; 52. through hole; 53. second shell. DETAILED DESCRIPTION

[0028] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme 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 described embodiments 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 creative work should fall within the scope of protection of the present invention.

[0029] The object 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 problem in the prior art of how to improve the sensitivity performance of the hydrophone and directly measure the vector signal.

[0030] The present invention is further described in detail below in conjunction with the accompanying drawings: Example 1 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 shell 5; the fixture 2 comprises a pressing plate 21 and a pressing block 23; the pressing plate 21 is a circular ring structure; and a clamping portion 22 is extended at 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 pressing block 23 to form 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 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 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 pressing block 23; the pressing plate 21 is fixedly arranged in the rubber shell 5, and the rubber shell 5 is filled with castor oil, and the other ends of the two wires 3 penetrate the rubber shell 5 and extend to the outside to be connected to the electrode end.

[0031] 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.

[0032] The first piezoelectric ceramic sheet 11 and the second piezoelectric ceramic sheet 12 are of equal size.

[0033] In this embodiment, the first piezoelectric ceramic sheet 11 and the second piezoelectric ceramic sheet 12 are made of PZT-5H piezoelectric ceramic sheets.

[0034] In this embodiment, when the acoustic signal is transmitted to the double-layer piezoelectric ceramic component 1, the double-layer piezoelectric ceramic component 1 bends and deforms, and under the action of the piezoelectric effect and the flexoelectric effect, the upper and lower surfaces of the double-layer piezoelectric ceramic component 1 induce charges of opposite polarities, and output current through the wire 3. The piezoelectric effect and the flexoelectric effect are the basis for the hydrophone to receive acoustic wave signals and convert them into electrical signals.

[0035] Specifically, according to Figure 3 and Figure 4 As shown, two groups of connection holes are respectively provided on the clamping portion 22 and the pressing block 23, and the two groups of connection 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 assembly 1, and the pressing block 23 is pressed onto the clamping portion 22 by the first bolt assembly 4.

[0036] 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 .

[0037] In this embodiment, two groups of connection holes are respectively provided on the clamping portion 22 and the pressing block 23. The design of these connection holes enables the first bolt assembly 4 to be threaded therein, 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 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 will be transmitted to the double-layer piezoelectric ceramic component 1. Since the double-layer piezoelectric ceramic component 1 is formed by the first piezoelectric ceramic sheet 11 and the second piezoelectric ceramic sheet 12 being bonded relative to each other, they will jointly respond to the changes in the pressure of the sound waves. Under the combined action of the piezoelectric effect and the flexoelectric effect, the double-layer piezoelectric ceramic component 1 will generate an electric charge, which will be 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.

[0038] 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.

[0039] 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 .

[0040] The pressure plate 21 and the mounting rings of the first shell 51 and the second shell 53 are provided with a plurality of fixing holes in a circumferential direction corresponding to each other; A plurality of second bolt assemblies 6 are correspondingly threadedly connected in the plurality of fixing holes, and the pressing plate 21 is annularly fixed on the mounting rings of the first shell 51 and the second shell 53 by the plurality of second bolt assemblies 6 .

[0041] 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.

[0042] After the first shell 51 and the second shell 53 are filled with castor oil, the through hole 52 is sealed with epoxy resin.

[0043] In this embodiment, when sound waves act on the low-frequency double-layer vector hydrophone, the pressure changes generated by the sound waves will be transmitted to the shell of the hydrophone, especially the first shell 51 and the second shell 53. Since the two shells are relatively connected and together form a complete hollow spherical structure, they can effectively receive sound wave signals from all directions. The sound wave signal is further transmitted to the double-layer piezoelectric ceramic component 1, which is formed by the first piezoelectric ceramic sheet 11 and the second piezoelectric ceramic sheet 12 being relatively bonded. Under the action of the sound wave pressure, the double-layer piezoelectric ceramic component 1 will generate an electric charge, and the change in this charge represents the intensity and frequency of the sound wave signal. The charge generated by the double-layer piezoelectric ceramic component 1 is transmitted to the electrode end through the wire 3. One end of the wire 3 is connected to the upper and lower surfaces of the double-layer piezoelectric ceramic component 1, and the other end extends to the outside through the through hole 52 on the first shell 51 and is connected to the electrode end. Among them, before filling the castor oil, the wire 3 has been pre-installed through the through hole 52. After filling the castor oil, the through hole 52 will be sealed with epoxy resin to ensure the sealing inside the shell and prevent external contaminants from entering.

[0044] 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, a stronger electrical signal output can be generated, 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.

[0045] Example 2 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 as described above, comprising the following steps: A polarized 25 mm × 20 mm × 1 mm PZT-5H piezoelectric ceramic sheet is prepared, and two small rectangular PZT-5H piezoelectric ceramic sheets of 25 mm × 10 mm × 1 mm are cut out of the sheet using a STX-202A diamond wire cutting machine, namely a first piezoelectric ceramic sheet 11 and a second piezoelectric ceramic sheet 12. Figure 1 As shown; Polish the negative electrodes of the first piezoelectric ceramic sheet 11 and the second piezoelectric ceramic sheet 12 using a metallographic sample grinder and polisher, and adjust the speed of the grinder and polisher to 50r / min. After the polished surfaces of the first piezoelectric ceramic sheet 11 and the second piezoelectric ceramic sheet 12 are polished to be clear and bright, wipe them with anhydrous alcohol. After the alcohol is naturally air-dried, drop two drops of ceramic glue on the polished surface of the negative electrode of the first piezoelectric ceramic sheet 11, and cover the polished surface of the negative electrode of the second piezoelectric ceramic sheet 12 on the first piezoelectric ceramic sheet 11 in a completely overlapping manner, 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.

[0046] The material of fixture 2 is 3mm thick acrylic plate. A laser engraving machine is used to laser 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 3 As shown, the clamp 2 is divided into a pressing plate 21 and a pressing block 23. The pressing block 23 is a small cuboid 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 pressing block 23. The center of the connecting hole is on the perpendicular bisector of the pressing block 23 along the width direction. The pressing 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 center of the connecting hole is on the perpendicular bisector of the clamping portion 22 along the width direction. 4mm away from the edge of the outer ring of the pressing plate 21, fixing holes with a diameter of 4mm are evenly provided along the circumference of the ring, as shown in FIG. Figure 3 shown.

[0047] according to Figure 4As shown, the short side of the double-layer piezoelectric ceramic component 1 is placed in the middle of the two connection holes at the inner ring clamping part 22 of the pressing plate 21 of the fixture 2. The pressing block 23 is aligned with the inner ring clamping part 22 of the pressing plate 21, and two first bolt assemblies 4 are used to fasten the double-layer piezoelectric ceramic component 1 between the pressing plate 21 and the pressing block 23 through the connection holes, so that the double-layer piezoelectric ceramic component 1 forms a cantilever beam structure. A wire 3 is provided in the middle of the double-layer piezoelectric ceramic component 1, the pressing block 23 and the fixing part of the pressing plate 21.

[0048] according to Figure 5 As shown, the rubber shell 5 of the double-layer vector hydrophone is made of polyurethane rubber, and the thickness of the rubber shell 5 is 1 mm. A layer of copper paint is evenly applied to the inside 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 ring diameter of 71 mm, an inner ring diameter of 51 mm and a hollow hemispherical shell with an inner diameter of 51 mm. At a distance of 4 mm from the outer ring edge of the first shell 51, a fixing hole with a diameter of 4 mm is evenly arranged along the circumference of the circular ring. The second shell 53 is also composed of a circular ring with an outer ring diameter of 71 mm, an inner ring diameter of 51 mm and a hollow hemispherical shell with an inner diameter of 51 mm. At a distance of 4 mm from the outer ring edge of the lower shell 9b, a fixing hole with a diameter of 4 mm is evenly arranged along the circumference of the circular ring. There is a through hole 52 with a diameter of 4 mm on the hollow hemispherical shell of the first shell 51.

[0049] The clamp 2 is located 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 at the same time. The double-layer vector hydrophone is packaged and fastened 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 to complete 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.

[0050] In this embodiment, according to Fig. 9 Shown is the working principle diagram of the low-frequency double-layer vector hydrophone: When the sound signal is transmitted to the cantilever beam, the cantilever beam bends and deforms, and the cantilever beam is pulled above the neutral layer and compressed below the neutral layer. The polarization direction generated by the piezoelectric effect above the neutral layer of the single-layer vector hydrophone is from bottom to top, and the polarization direction generated by the piezoelectric effect below the neutral layer is from top to bottom. The piezoelectrics cancel each other out, and only the flexoelectric effect exists. The polarization direction generated by the piezoelectric effect of the first piezoelectric ceramic sheet 11 of the double-layer vector hydrophone is from bottom to top. Since the piezoelectric effect is directional, the polarization direction generated by the piezoelectric effect of the second piezoelectric ceramic sheet 12 in the lower layer, which is reversely bonded, is also from bottom to top. At the same time, there is also a flexoelectric effect. The polarization direction of the flexoelectric effect is consistent with the polarization direction generated by the piezoelectric effect, and its effective flexoelectric effect is enhanced. Therefore, the cantilever beam structure of the double-layer vector hydrophone can have a larger output and higher sensitivity than the single-layer cantilever beam. The output of the double-layer vector hydrophone is a combination of the piezoelectric effect and the flexoelectric effect, which can be regarded 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.

[0051] In summary, the present invention also provides a method for manufacturing a low-frequency double-layer vector hydrophone with flexoelectric and piezoelectric effects. By cutting two polarized piezoelectric ceramic sheets into rectangular blocks of the same size and bonding them into a whole, a high-performance double-layer piezoelectric ceramic component 1 is obtained, and by combining the piezoelectric effect and the flexoelectric effect, the sensitivity and measurement accuracy of the hydrophone are improved. The acrylic plate is laser cut by a laser engraving machine to accurately obtain the pressing plate 21 and the pressing block 23, and a clamping portion 22 is formed on the inner side of the pressing plate 21, ensuring the accuracy and stability of the fixture 2, thereby improving the overall performance of the hydrophone. The upper and lower surfaces of the double-layer piezoelectric ceramic component 1 are respectively provided with wires 3 between the clamping portion 22 and the pressing block 23. These wires 3 are led out through the rubber housing 5 and connected to the electrode end, ensuring the reliable transmission of the signal and facilitating subsequent maintenance and testing. A layer of copper paint is evenly applied inside the rubber housing 5 to effectively shield 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.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant 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 within 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 comprises 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; The 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 of the wires (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) penetrate the rubber housing (5) and extend to the outside to be connected to the electrode ends.

2. A low-frequency double-layer vector hydrophone with flexoelectric and piezoelectric effects according to claim 1, characterized in that: 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.

3. A low-frequency double-layer vector hydrophone with flexoelectric and piezoelectric effects according to claim 2, characterized in that: The first piezoelectric ceramic sheet (11) and the second piezoelectric ceramic sheet (12) are of equal size.

4. 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 against the clamping portion (22) by the first bolt assembly (4).

5. 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 pressing plate (21) is greater than the length of the double-layer piezoelectric ceramic component (1).

6. The low-frequency double-layer vector hydrophone with flexoelectric and piezoelectric effects according to claim 1, characterized in that: 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).

7. A low-frequency double-layer vector hydrophone with flexoelectric and piezoelectric effects according to claim 6, 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 circumferential direction corresponding to each other; 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 on the mounting rings of the first shell (51) and the second shell (53) by the plurality of second bolt assemblies (6).

8. The low-frequency double-layer vector hydrophone with flexoelectric and piezoelectric effects according to claim 6, characterized in that: 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.

9. The low-frequency double-layer vector hydrophone with flexoelectric and piezoelectric effects according to claim 8, 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.

10. 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 9 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 cutting machine, and bond the two piezoelectric ceramic sheets into a whole to obtain a double-layer piezoelectric ceramic assembly (1); Using a laser engraving machine to laser cut the acrylic plate to obtain a pressing plate (21) and a pressing block (23), and laser cutting the inner side of the pressing plate (21) to form a clamping portion (22); The short side of the double-layer piezoelectric ceramic component (1) is placed on the clamping portion (22) and clamped by a pressing block (23); wherein wires (3) are provided between the upper and lower surfaces of the double-layer piezoelectric ceramic component (1) and 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 fixture (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 portion (22) and the pressing 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; and the preparation of the low-frequency double-layer vector hydrophone is completed.

Images