Low-frequency double-layer vector hydrophone with flexural voltage and piezoelectric effect and manufacturing method thereofTechnical Field
The invention relates to the technical field of sensing, in particular to a low-frequency double-layer vector hydrophone with flexural voltage and piezoelectric effect and a manufacturing method thereof.
Background
In the field of marine exploration, many countries are devoted to developing underwater sound detection technology in order to enhance sonar detection and combat capability of ships. Hydrophones are important parts of sonar, and are used for receiving acoustic signals in water, and are widely used for underwater communication, target positioning, tracking and the like. Due to the physical limitations of seawater on the propagation of sound waves, high frequency sound waves become low frequency sound waves as they propagate from the far field. Compared with a scalar hydrophone, the vector hydrophone is a special underwater sensor specially designed for measuring underwater acoustic signals, and has stronger applicability to low-frequency sound waves. Unlike scalar hydrophones, which are used to measure signal amplitude, vector hydrophones are capable of measuring the magnitude and direction of underwater sound. Thus, the vector hydrophone can determine the complete sound velocity vector and provide a more complete and accurate characterization of the underwater sound field.
The current common vector hydrophones mainly comprise piezoresistive hydrophones, capacitive hydrophones, piezoelectric hydrophones and flexoelectric hydrophones. Compared with a piezoresistive hydrophone and a capacitive hydrophone, the piezoelectric hydrophone and the flexoelectric hydrophone are passive hydrophones, the piezoresistive hydrophone has low transduction efficiency, and the capacitive hydrophone is easily affected by parasitic capacitance. The piezoelectric hydrophone has the advantages of low cost and high stability, but cannot directly measure vector signals such as pressure gradient and the like. The ability of a hydrophone to directly measure vector signals such as pressure gradients is limited by the relatively low flex coefficient that can affect the sensitivity performance of the hydrophone. Thus, a compromise is proposed to enhance the flexoelectric effect, i.e. the flexoelectric effect-like. The flexoelectric-like effect has a similar electromechanical coupling effect as flexoelectricity. The principle of the flexoelectric-like effect is to enhance the effective flexoelectric coefficient in any possible way. Compared with other deflection effects, the high-sensitivity low-frequency hydrophone capable of directly measuring vector signals is particularly important to design by combining the advantages of the piezoelectric effect and the deflection effect.
Disclosure of Invention
In order to overcome the defects in the prior art, the invention aims to provide a low-frequency double-layer vector hydrophone with flexural voltage and piezoelectric effect and a manufacturing method thereof, so as to solve the technical problems of how to improve the sensitivity performance of the hydrophone and directly measure vector signals in the prior art.
The invention is realized by the following technical scheme:
In a first aspect, the invention provides a low-frequency double-layer vector hydrophone with flex voltage and piezoelectric effect, which comprises a double-layer piezoelectric ceramic component, a clamp, two wires and a rubber shell;
the clamp comprises a pressing plate and a pressing block, wherein the pressing plate is of a circular ring structure, and a clamping part is arranged at the inner side wall in an extending manner;
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 a pressing block to form an cantilever beam type structure;
The two wires are respectively arranged between the double-layer piezoelectric ceramic component and the clamping part and between the pressing block, wherein the end part of one wire is clamped between the bottom surface of the double-layer piezoelectric ceramic component and the top surface of the clamping part;
The clamp plate is fixed to be set up in the rubber casing, fill castor oil in the rubber casing, the other tip of two wires runs through the rubber casing and extends to external connection to electrode terminal respectively.
Preferably, the double-layer piezoelectric ceramic assembly comprises a first piezoelectric ceramic piece and a second piezoelectric ceramic piece, wherein the first piezoelectric ceramic piece and the second piezoelectric ceramic piece are oppositely bonded.
Further, the first piezoelectric ceramic plate and the second piezoelectric ceramic plate are equal in size.
Preferably, two groups of connecting holes are correspondingly formed in the clamping part and the pressing block respectively, first bolt assemblies are correspondingly connected in the two groups of connecting holes in a threaded manner respectively, the pressing block cover is arranged at one end of the double-layer piezoelectric ceramic assembly, and the pressing block is pressed on the clamping part through the first bolt assemblies.
Preferably, the diameter of the inner circular ring of the pressing plate is larger than the length of the double-layer piezoelectric ceramic component.
Preferably, the rubber housing includes a first housing and a second housing;
The first shell and the second shell are hollow hemispherical shells, and are connected relatively, and the pressing plate is clamped between the first shell and the second shell;
The pressing plate is annularly fixed on the mounting rings of the first shell and the second shell.
Furthermore, a plurality of fixing holes are correspondingly arranged on the mounting rings of the pressing plate and the first shell and the second shell in the circumferential direction;
A plurality of second bolt assemblies are correspondingly connected in the plurality of fixing holes in a threaded manner, and the pressing plate is fixed on the mounting rings of the first shell and the second shell in a circumferential direction through the plurality of second bolt assemblies.
Furthermore, through holes are arranged on the shell wall of the first shell and are used for filling castor oil into the first shell and the second shell, and the other ends of the two wires respectively extend to the outside through the through holes and are connected to the electrode terminals.
Furthermore, after the castor oil is filled in the first shell and the second shell, the through holes are sealed by epoxy resin.
In a second aspect, the present invention further provides a method for manufacturing a low-frequency double-layer vector hydrophone with flex voltage and piezoelectric effect, which is used for obtaining the low-frequency double-layer vector hydrophone with flex voltage and piezoelectric effect, and includes the following steps:
Preparing polarized piezoelectric material ceramic plates, cutting the piezoelectric material ceramic plates into two cuboid piezoelectric material ceramic plates with the same size by using a diamond wire cutting machine, and bonding the two piezoelectric material ceramic plates into a whole to obtain a double-layer piezoelectric ceramic assembly;
carrying out laser cutting on the acrylic plate by adopting a laser engraving machine to obtain a pressing plate and a pressing block, and forming a clamping part on the inner side of the pressing plate by laser cutting;
Placing one side of the short side of the double-layer piezoelectric ceramic component on the clamping part and clamping the double-layer piezoelectric ceramic component by the pressing block, wherein a lead is arranged between the upper surface and the lower surface of the double-layer piezoelectric ceramic component and the clamping part and the pressing block respectively;
A layer of copper paint is uniformly coated in the rubber shell for shielding electromagnetic interference, the clamp is fixed in the rubber shell, the upper surface and the lower surface of the double-layer piezoelectric ceramic assembly respectively penetrate through the rubber shell and the other end of a wire between the clamping part and the pressing block to be led out and connected to an electrode end, castor oil is filled in the rubber shell, the rubber shell is sealed by epoxy resin, and the preparation work of the low-frequency double-layer vector hydrophone is completed.
Compared with the prior art, the invention has the following beneficial technical effects:
The invention provides a low-frequency double-layer vector hydrophone with flexural voltage and piezoelectric effect, which can capture low-frequency sound wave signals more effectively by adopting a double-layer piezoelectric ceramic assembly. The design of the double-layer structure optimizes the piezoelectric effect, so that stronger electric signal output can be generated under the same external acoustic wave excitation, and the detection sensitivity of the low-frequency acoustic wave is improved. The invention utilizes the flexoelectric effect, under the action of sound waves, the double-layer piezoelectric ceramic component not only generates longitudinal compression or stretching deformation, but also generates transverse bending deformation, and meanwhile, the cantilever structure enables the double-layer vector hydrophone to directly measure vector signals. The multidirectional deformation further enhances the electric energy conversion efficiency of the double-layer piezoelectric ceramic component, so that the hydrophone can more comprehensively respond to acoustic wave signals, and the accuracy and precision of measurement are improved.
Further, the double-layer piezoelectric ceramic component comprises a first piezoelectric ceramic piece and a second piezoelectric ceramic piece, and the first piezoelectric ceramic piece and the second piezoelectric ceramic piece are oppositely bonded. By bonding the two piezoelectric ceramic plates, a stronger and more stable structure can be formed, which is helpful for reducing performance degradation caused by possible defects or damage of the single piezoelectric ceramic plate. Meanwhile, the bonding layer can also play a role in buffering and damping, so that the durability and reliability of the double-layer piezoelectric ceramic component are further improved.
Furthermore, the first piezoelectric ceramic plates and the second piezoelectric ceramic plates are equal in size, and the piezoelectric ceramic plates with equal sizes can distribute stress more uniformly when being subjected to external force. This means that each part can respond to external stimuli in a similar way throughout the double-layer piezoceramic assembly, thereby reducing the risk of performance degradation or damage due to stress concentrations.
Further, two groups of connecting holes are correspondingly formed in the clamping part and the pressing block respectively, first bolt assemblies are correspondingly connected in the two groups of connecting holes in a threaded mode respectively, the pressing block cover is arranged at one end of the double-layer piezoelectric ceramic assembly, and the pressing block is pressed on the clamping part through the first bolt assemblies. The pressing block is tightly pressed on the clamping part through the first bolt component, so that the double-layer piezoelectric ceramic component can be firmly clamped, sufficient clamping force is provided, the double-layer piezoelectric ceramic component is prevented from loosening or falling off under the action of vibration or external force, and the stability and the reliability of the double-layer piezoelectric ceramic component in the working process are ensured.
Further, the diameter of the inner circular ring of the pressing plate is larger than the length of the double-layer piezoelectric ceramic component, and the double-layer piezoelectric ceramic component cannot touch the bottom edge of the pressing plate during clamping, so that stress concentration and potential damage risks caused by edge contact are reduced, the clamping stability is improved, and the integrity and performance of the double-layer piezoelectric ceramic component can be kept under the action of vibration or external force.
The rubber shell comprises a first shell and a second shell, wherein the first shell and the second shell are hollow hemispheric shells, the first shell and the second shell are connected relatively, a pressing plate is clamped between the first shell and the second shell, and the pressing plate is fixed on mounting rings of the first shell and the second shell in a circumferential direction. By dividing the rubber housing into two hemispherical portions, a first housing and a second housing, and sandwiching the pressure plate therebetween, a stronger and sealed structure can be formed. This design not only increases the overall strength of the housing, but also ensures effective protection of the internal components while preventing intrusion of external moisture, dust or other contaminants.
Furthermore, a plurality of fixing holes are correspondingly formed in the annular directions of the pressing plate and the mounting rings of the first shell and the second shell, a plurality of second bolt assemblies are correspondingly connected in the plurality of fixing holes in a threaded manner, the pressing plate is annularly fixed on the mounting rings of the first shell and the second shell through the plurality of second bolt assemblies, the pressing plate is annularly fixed on the mounting rings of the first shell and the second shell through the second bolt assemblies, firm connection between the pressing plate and the shells can be ensured, stability of the whole structure is improved, and loosening or deformation risks caused by vibration or external force effect are reduced.
Furthermore, through holes are arranged on the shell wall of the first shell and are used for filling castor oil into the first shell and the second shell, and the other ends of the two groups of wires respectively extend to the outside through the through holes and are connected to the electrode ends. The through-hole allows the operator to fill castor oil into the housing conveniently through it. Castor oil, which is a commonly used acoustic medium, has good acoustic and sealing properties, can effectively transmit sound waves and prevent external contaminants from entering the interior of the housing. The lead is extended to the outside through the through hole, and can be conveniently connected to the electrode terminal or other electronic devices. This design makes the wire arrangement cleaner and less prone to potential failure due to wire clutter. Meanwhile, the device is convenient for subsequent maintenance and replacement work.
Furthermore, after the castor oil is filled in the first shell and the second shell, the through holes are sealed by epoxy resin. Epoxy resins are a high performance sealing material with excellent adhesion and chemical resistance. The through holes are sealed by using epoxy resin, so that castor oil in the shell can be prevented from leaking, and external moisture, dust or other pollutants are prevented from entering the shell.
The invention also provides a manufacturing method of the low-frequency double-layer vector hydrophone with the flexural voltage and the piezoelectric effect, which is characterized in that two pieces of polarized piezoelectric material ceramic plates are cut into cuboids with the same size and are bonded into a whole, so that a high-performance double-layer piezoelectric ceramic assembly is obtained, and the sensitivity and the measurement accuracy of the hydrophone are improved by combining the piezoelectric effect and the flexural voltage effect. The acrylic plate is cut by the laser engraving machine, the pressing plate and the pressing block can be accurately obtained, the clamping part is formed on the inner side of the pressing plate, the accuracy and the stability of the clamp are ensured, and therefore the overall performance of the hydrophone is improved. Wires are arranged between the upper surface and the lower surface of the double-layer piezoelectric ceramic component and the clamping part and the pressing block respectively, and are led out through the rubber shell and connected to the electrode terminals, so that reliable transmission of signals is ensured, and subsequent maintenance and testing are facilitated. A layer of copper paint is uniformly coated in the rubber shell, so that electromagnetic interference can be effectively shielded. The rubber shell is sealed by epoxy resin, so that castor oil in the shell can be prevented from leaking, and external pollutants are prevented from entering.
Further, when an acoustic signal is transmitted to a cantilever beam in the double-layer vector hydrophone, the cantilever beam is bent and deformed, and the cantilever beam is pulled above a neutral layer and is pressed below the neutral layer. The polarization direction of the upper piezoelectric ceramic plate of the double-layer vector hydrophone is from bottom to top, and the polarization direction of the lower reversely-bonded piezoelectric ceramic plate is from bottom to top due to the directivity of the piezoelectric effect, meanwhile, the flexoelectric effect exists, the polarization direction of the flexoelectric effect is consistent with the polarization direction of the piezoelectric effect, the effective flexoelectric effect is enhanced, and the output of the hydrophone is obviously improved.
Furthermore, the double-layer vector hydrophone has higher sensitivity than the traditional vector hydrophone, and the output of the double-layer vector hydrophone is the combination of the piezoelectric effect and the flexoelectric effect, so that the double-layer vector hydrophone can be regarded as an integral effective flexoelectric effect, and the interference between the piezoelectric effect and the flexoelectric effect can be avoided. Meanwhile, the double-layer vector hydrophone has the same cantilever beam structure as the acoustic pressure gradient hydrophone, and can directly measure vector signals.
Drawings
FIG. 1 is a schematic diagram illustrating the separation of a two-layer piezoelectric ceramic component according to an embodiment of the present invention;
FIG. 2 is a schematic diagram showing a combination of a two-layer piezoelectric ceramic component according to an embodiment of the present invention;
FIG. 3 is a schematic view illustrating the disassembly of a jig according to an embodiment of the present invention;
FIG. 4 is a schematic structural diagram of a clamp clamping a dual-layer piezoelectric ceramic component according to an embodiment of the present invention;
FIG. 5 is a schematic view illustrating the disassembly of a rubber housing according to an embodiment of the present invention;
FIG. 6 is a schematic diagram of the split of a low frequency dual layer vector hydrophone in an embodiment of the invention;
FIG. 7 is an overall schematic diagram of a low frequency dual layer vector hydrophone in an embodiment of the invention;
FIG. 8 is a schematic cross-sectional view of a low frequency dual layer vector hydrophone in accordance with an embodiment of the invention;
FIG. 9 is a schematic diagram of the operation of a low frequency dual layer vector hydrophone in an embodiment of the invention;
1, a double-layer piezoelectric ceramic component; 2, a clamp, 3, a lead, 4, a first bolt component, 5, a rubber shell, 6, a second bolt component, 11, a first piezoelectric ceramic piece, 12, a second piezoelectric ceramic piece, 21, a pressing plate, 22, a clamping part, 23, a pressing block, 51, a first shell, 52, a through hole, 53 and a second shell.
Detailed Description
In order that those skilled in the art will better understand the present invention, a technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in which it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present invention without making any inventive effort, shall fall within the scope of the present invention.
The invention aims to provide a low-frequency double-layer vector hydrophone with flexural voltage and piezoelectric effect and a manufacturing method thereof, which are used for solving the technical problems of how to improve the sensitivity performance of the hydrophone and directly measure vector signals in the prior art.
The invention is described in further detail below with reference to the attached drawing figures:
Example 1
Referring to fig. 6 and 7, in one embodiment of the present invention, there is provided a low-frequency double-layer vector hydrophone with flexural voltage and piezoelectric effect, which comprises a double-layer piezoelectric ceramic component 1, a clamp 2, two wires 3 and a rubber housing 5, wherein the clamp 2 comprises a pressing plate 21 and a pressing block 23, the pressing plate 21 is in a circular ring structure, a clamping part 22 is arranged at the inner side wall in an extending mode, one end of the double-layer piezoelectric ceramic component 1 is placed on the clamping part 22, the double-layer piezoelectric ceramic component 1 is clamped on the clamping part 22 through the pressing block 23 to form an 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, the end part 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 part 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, castor oil is filled in the rubber housing 5, and the other end part of the two wires 3 respectively extends to the external electrode ends through the rubber housing 5.
Specifically, as shown in fig. 1 and 2, the double-layer piezoelectric ceramic assembly 1 includes a first piezoelectric ceramic piece 11 and a second piezoelectric ceramic piece 12, where the first piezoelectric ceramic piece 11 and the second piezoelectric ceramic piece 12 are oppositely bonded.
Wherein, the first piezoelectric ceramic piece 11 and the second piezoelectric ceramic piece 12 are equal in size.
In this embodiment, the first piezoelectric ceramic plate 11 and the second piezoelectric ceramic plate 12 are PZT-5H piezoelectric ceramic plates.
In this embodiment, when an acoustic signal is transmitted to the double-layer piezoelectric ceramic assembly 1, the double-layer piezoelectric ceramic assembly 1 is bent and deformed, charges with opposite polarities are induced on the upper and lower surfaces of the double-layer piezoelectric ceramic assembly 1 under the action of the piezoelectric effect and the flexoelectric effect, and a current is output through the lead 3. The piezoelectric effect and the flexoelectric effect are the basis for the hydrophone to be able to receive acoustic signals and convert them into electrical signals.
Specifically, as shown in fig. 3 and fig. 4, two sets of connecting holes are correspondingly formed in the clamping portion 22 and the pressing block 23, the first bolt assemblies 4 are correspondingly connected in the two sets of connecting holes in a threaded manner, the pressing block 23 is covered at one end of the double-layer piezoelectric ceramic assembly 1, and the pressing block 23 is pressed on the clamping portion 22 through the first bolt assemblies 4.
Specifically, the diameter of the inner circular ring of the pressing plate 21 is larger than the length of the double-layer piezoelectric ceramic assembly 1.
In this embodiment, two sets of connection holes are correspondingly provided on the clamping portion 22 and the pressing block 23, respectively, and the connection holes are designed to enable the first bolt assembly 4 to be screwed therein, so as to press the pressing block 23 onto the clamping portion 22. This fastening ensures that one end of the double-layered piezoelectric ceramic assembly 1 is stably clamped and fixed. The diameter of the inner circular ring of the pressing plate 21 is larger than the length of the double-layer piezoelectric ceramic assembly 1, and the design allows a certain space between the clamping part 22 and the pressing block 23 of the double-layer piezoelectric ceramic assembly 1, and simultaneously ensures that the double-layer piezoelectric ceramic assembly 1 can be completely covered and fixed. When an acoustic wave acts on the low-frequency double-layer vector hydrophone, pressure changes generated by the acoustic wave are transmitted to the double-layer piezoelectric ceramic assembly 1. Since the double-layer piezoelectric ceramic assembly 1 is formed by relatively bonding the first piezoelectric ceramic piece 11 and the second piezoelectric ceramic piece 12, they collectively respond to the change of the acoustic wave pressure. Under the combined action of the piezoelectric effect and the flexoelectric effect, the double-layer piezoelectric ceramic component 1 generates charges and transmits the charges to the electrode terminals through the lead wires 3. These changes in charge represent the intensity and frequency of the acoustic signal, thereby effecting conversion of the acoustic signal to an electrical signal.
Specifically, according to fig. 5, the rubber housing 5 includes a first housing 51 and a second housing 53, wherein the rubber housing 5 is made of polyurethane rubber.
The first shell 51 and the second shell 53 are hollow hemispherical shells, and the first shell 51 and the second shell 53 are oppositely connected, and the pressing plate 21 is clamped between the first shell 51 and the second shell 53;
The pressure plate 21 is fixed to the mounting rings of the first housing 51 and the second housing 53 in a circumferential direction.
Wherein, the mounting rings of the pressing plate 21 and the first shell 51 and the second shell 53 are provided with a plurality of fixing holes correspondingly in the circumferential direction;
The plurality of fixing holes are respectively and correspondingly connected with a plurality of second bolt assemblies 6 in a threaded manner, and the pressing plate 21 is fixed on the mounting rings of the first shell 51 and the second shell 53 in a circumferential direction through the plurality of second bolt assemblies 6.
Wherein, through holes 52 are arranged on the shell wall of the first shell 51 and used for filling castor oil into the first shell 51 and the second shell 53 through the through holes 52, and the other ends of the two leads 3 respectively extend to the outside through the through holes 52 and are connected to the electrode terminals.
After the castor oil is filled in the first housing 51 and the second housing 53, the through hole 52 is sealed by epoxy resin.
In this embodiment, when acoustic waves are applied to the low frequency dual layer vector hydrophone, the pressure changes generated by the acoustic waves are transmitted to the hydrophone housing, and in particular the first housing 51 and the second housing 53. Since the two housings are connected in opposition and together form a complete hollow sphere structure, they are able to effectively receive acoustic signals from all directions. The acoustic wave signal is further transmitted to the double-layer piezoelectric ceramic assembly 1, which is formed by relatively bonding the first piezoelectric ceramic piece 11 and the second piezoelectric ceramic piece 12. Under the influence of the acoustic wave pressure, the double-layer piezoelectric ceramic assembly 1 generates an electric charge, and the change of the electric charge represents the intensity and the frequency of the acoustic wave signal. The charges generated by the double-layer piezoelectric ceramic assembly 1 are transferred to the electrode terminals through the lead wires 3. One end of the lead wire 3 is connected to the upper and lower surfaces of the double-layered piezoelectric ceramic assembly 1, and the other end is extended to the outside through the through hole 52 of the first housing 51 to be connected to the electrode terminal. Wherein the wire 3 has been pre-installed through the through hole 52 before filling with castor oil. After the castor oil is filled, the through hole 52 is sealed with epoxy resin to ensure sealability in the case and prevent external contaminants from entering.
In summary, the low-frequency double-layer vector hydrophone with flex voltage and piezoelectric effect provided by the invention can capture low-frequency sound wave signals more effectively by adopting the double-layer piezoelectric ceramic component 1. The design of the double-layer structure optimizes the piezoelectric effect, so that stronger electric signal output can be generated under the same external acoustic wave excitation, and the detection sensitivity of the low-frequency acoustic wave is improved. The invention utilizes the flexoelectric effect, under the action of sound waves, the double-layer piezoelectric ceramic component 1 not only generates longitudinal compression or stretching deformation, but also generates transverse bending deformation, and meanwhile, the cantilever structure enables the double-layer vector hydrophone to directly measure vector signals. The multidirectional deformation further enhances the electric energy conversion efficiency of the double-layer piezoelectric ceramic component 1, so that the hydrophone can more comprehensively respond to acoustic wave signals, and the accuracy and precision of measurement are improved.
Example 2
The embodiment provides a manufacturing method of a low-frequency double-layer vector hydrophone with flex voltage and piezoelectric effect, which is used for obtaining the low-frequency double-layer vector hydrophone with flex voltage and piezoelectric effect, and comprises the following steps:
preparing a polarized PZT-5H piezoelectric ceramic plate with the size of 25mm multiplied by 20mm multiplied by 1mm, and cutting the PZT-5H piezoelectric ceramic plate into two small cuboid PZT-5H piezoelectric ceramic plates with the size of 25mm multiplied by 10mm multiplied by 1mm by using an STX-202A diamond wire cutting machine, namely a first piezoelectric ceramic plate 11 and a second piezoelectric ceramic plate 12, as shown in figure 1;
and (3) carrying out negative electrode polishing and grinding on the first piezoelectric ceramic plate 11 and the second piezoelectric ceramic plate 12 by adopting a metallographic specimen polishing and grinding machine, and regulating the rotating speed of the polishing and grinding machine to 50r/min. Polishing the polished surfaces of the first piezoelectric ceramic piece 11 and the second piezoelectric ceramic piece 12 until the polished surfaces are clear and bright, and wiping the polished surfaces by absolute alcohol. After the alcohol is naturally dried, two drops of ceramic glue are dropped on the polished surface of the negative electrode of the first piezoelectric ceramic plate 11, the polished surface of the negative electrode of the second piezoelectric ceramic plate 12 is covered on the first piezoelectric ceramic plate 11 in a completely overlapped way, so that the first piezoelectric ceramic plate 11 and the second piezoelectric ceramic plate 12 are bonded into a whole-double-layer piezoelectric ceramic assembly 1, and the size of the double-layer piezoelectric ceramic assembly 1 is 25mm multiplied by 10mm multiplied by 2mm, as shown in figure 2.
The material of the clamp 2 is selected to be an acrylic plate with the thickness of 3 mm. And (3) carrying out laser cutting on the acrylic plate with the thickness of 3mm by adopting a laser engraving machine, wherein the power of a laser tube is 80W, the cutting power is set to be 45%, and the cutting speed is set to be 20. As shown in fig. 3, the jig 2 is divided into a pressing plate 21 and a pressing block 23. The press block 23 is a small cuboid with the size of 28mm multiplied by 5mm multiplied by 3mm, two connecting holes with the diameter of 1mm and the center distance of 18mm are symmetrically arranged along the length direction of the press block 23, and the center of each connecting hole is positioned on the perpendicular bisector of the press block 23 along the width direction. The whole pressing plate 21 is in a circular ring shape, the diameter of an outer ring is 71mm, the diameter of an inner ring is 51mm, the inner ring extends along the direction of the center of a circle to form a clamping part 22 with the length of 28mm and the width of 5mm, two connecting holes with the center of a circle being 18mm apart and the diameter of 1mm are symmetrically arranged along the length direction of the clamping part 22, and the center of the connecting holes is positioned on the perpendicular bisector of the clamping part 22 along the width direction. Fixing holes with diameters of 4mm are uniformly formed in the circumferential direction of the circular ring at the position 4mm away from the outer ring edge of the pressing plate 21, as shown in fig. 3.
According to fig. 4, the short side of the double-layered piezoelectric ceramic component 1 is placed in the middle of two connection holes at the inner ring clamping part 22 of the pressing plate 21 of the jig 2. The pressing block 23 is aligned with the inner ring clamping part 22 of the pressing plate 21, the double-layer piezoelectric ceramic assembly 1 is fastened between the pressing plate 21 and the pressing block 23 through the connecting holes by adopting two first bolt assemblies 4 respectively, and the double-layer piezoelectric ceramic assembly 1 forms an cantilever beam type structure. And a lead 3 is respectively arranged between the double-layer piezoelectric ceramic component 1 and the clamped part of the pressing block 23 and the pressing plate 21.
According to FIG. 5, the rubber housing 5 of the double-layer vector hydrophone is made of polyurethane rubber, and the thickness of the rubber housing 5 is 1mm. A layer of copper paint is uniformly coated in the rubber shell 5, so that electromagnetic interference can be effectively shielded. The rubber housing 5 is divided into a first housing 51 and a second housing 53. The first shell 51 is composed of an outer ring with the diameter of 71mm, a circular ring with the inner ring diameter of 51mm and a hollow hemispherical shell with the inner diameter of 51mm, and fixing holes with the diameter of 4mm are uniformly formed in the circumferential direction of the circular ring at the position 4mm away from the edge of the outer ring of the first shell 51. The second shell 53 is also composed of an outer ring with the diameter of 71mm, a ring with the diameter of 51mm and a hollow hemispherical shell with the inner diameter of 51mm, and fixing holes with the diameter of 4mm are uniformly formed in the circumferential direction of the ring at the position 4mm away from the outer ring edge of the lower shell 9 b. A through hole 52 having a diameter of 4mm is provided in the hollow half sphere of the first housing 51.
The clamp 2 is positioned in the middle of the rubber shell 5, and the fixing holes of the first shell 51, the clamp 2 and the second shell 53 are aligned at the same time, and the double-layer vector hydrophone package is fastened by adopting the second bolt assemblies 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 holes 52 are sealed by epoxy resin, and the assembly of the low-frequency double-layer vector hydrophone is completed, as shown in fig. 6 and 7. A cross-sectional view of a dual layer PZT-5H vector hydrophone is shown in FIG. 8.
In this embodiment, a working schematic diagram of the low-frequency double-layer vector hydrophone is shown in fig. 9:
When the acoustic signal is transmitted to the cantilever beam, the cantilever beam is bent and deformed, the neutral layer of the cantilever beam is pulled above, and the neutral layer is pressed below. The polarization direction generated by the piezoelectric effect above the neutral layer of the single-layer vector hydrophone is from bottom to top, the polarization direction generated by the piezoelectric effect below the neutral layer is from top to bottom, the piezoelectricity counteracts each other, and only the flexoelectric effect exists. The polarization direction of the first piezoelectric ceramic plate 11 of the double-layer vector hydrophone is from bottom to top, and the polarization direction of the second piezoelectric ceramic plate 12 of the lower layer reverse bonding is from bottom to top due to the directivity of the piezoelectric effect, meanwhile, the flexoelectric effect exists, the polarization direction of the flexoelectric effect is consistent with the polarization direction of the piezoelectric effect, and the effective flexoelectric effect is enhanced. Therefore, compared with a single-layer cantilever beam, the cantilever beam structure of the double-layer vector hydrophone can have larger output and higher sensitivity. The output of the double-layer vector hydrophone is a combination of the piezoelectric effect and the flexoelectric effect, and can be regarded as an integral effective flexoelectric effect. The double-layer vector hydrophone has the same cantilever beam structure as the acoustic pressure gradient hydrophone, and can directly measure vector signals.
In summary, the invention also provides a method for manufacturing the low-frequency double-layer vector hydrophone with the flexural voltage and the piezoelectric effect, which is characterized in that two piezoelectric material ceramic sheets which are polarized are cut into cuboids with the same size and are bonded into a whole to obtain the double-layer piezoelectric ceramic component 1 with high performance, and the sensitivity and the measurement accuracy of the hydrophone are improved by combining the piezoelectric effect and the flexural voltage effect. The acrylic plate is cut by a laser engraving machine, the pressing plate 21 and the pressing block 23 can be accurately obtained, the clamping part 22 is formed on the inner side of the pressing plate 21, the accuracy and the stability of the clamp 2 are ensured, and therefore the overall performance of the hydrophone is improved. Wires 3 are arranged between the upper surface and the lower surface of the double-layer piezoelectric ceramic component 1 and the clamping part 22 and the pressing block 23 respectively, and the wires 3 are led out through the rubber shell 5 and connected to electrode terminals, so that reliable transmission of signals is ensured, and subsequent maintenance and testing are facilitated. A layer of copper paint is uniformly coated in the rubber shell 5, so that electromagnetic interference can be effectively shielded. The rubber housing 5 is sealed with epoxy resin, so that the castor oil in the housing is prevented from leaking and external pollutants are prevented from entering.
Finally, it should be noted that the above embodiments are only for illustrating the technical solution of the present invention and not for limiting the same, and although the present invention has been described in detail with reference to the above embodiments, it should be understood by those skilled in the art that modifications and equivalents may be made to the specific embodiments of the present invention without departing from the spirit and scope of the present invention, and any modifications and equivalents are intended to be included in the scope of the claims of the present invention.