Multi-slit type circular ring underwater acoustic transducer

Abstract

The invention belongs to the technical field of underwater acoustic transducers, and relates to a multi-slit type circular ring underwater acoustic transducer, which comprises a plurality of vibration units which are axially symmetric and periodically distributed, and each vibration unit has the same structure and comprises a slit metal shell, a longitudinal driving source and a switching mass block; wherein the slotted metal shell is arc-shaped and is provided with one or more slots; the switching mass block is connected with the slotted metal shell and the longitudinal driving source and provides prestress for the longitudinal driving source. And the slotted metal shells of the plurality of vibration units jointly form a ring-shaped vibration radiation surface. Broadband emission is formed by coupling the bending vibration mode of the slotted radiant panel and the longitudinal vibration mode of the longitudinal driving rod, the effective bending radiation area is increased, the sound radiation efficiency is improved, and the transducer of the structure has the advantages of being small in size, low in frequency, capable of achieving broadband emission and the like and can be applied to the fields of low-frequency active sonar, deep-sea remote communication, marine environment monitoring and the like.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of underwater acoustic transducer, in particular, the present application relates to a multi-slotted ring underwater acoustic transducer. BACKGROUND

[0002] The research, development and utilization of the ocean cannot be separated from the sound wave, and the sound wave is the only information carrier that can be transmitted over long distances in the ocean. The exploration and development of marine resources, underwater communication and navigation of warships, underwater target detection and identification, environmental monitoring, and marine natural disaster prediction all rely on underwater acoustic technology. As the "eyes and ears" of underwater acoustic equipment, the performance of underwater acoustic transducers and arrays will directly affect the performance of the sonar system.

[0003] With the development of modern underwater acoustic technology, active sonar remote detection, underwater acoustic communication and other fields have put forward the demand for low frequency, large power, small size, wideband and deep water working characteristics of underwater acoustic transducers. Small platform carriers such as unmanned underwater vehicles, helicopters, unmanned ships and other fast mobile platform carriers have become the focus of the current stage of ocean development strategy, and the number of equipment is also increasing. It is an indispensable part of future ocean warfare, which further emphasizes the requirements and limitations on the size, weight, power and other parameters of sonar equipment.

[0004] The slotted ring transducer is a typical representative of low-frequency small-size structure, which is composed of a slotted metal shell and a mosaic ceramic driving source. The main vibration area is located at the slotted position of the metal ring, and the sound wave is radiated by using the bending mode of the metal ring. The stiffness of the slotted metal ring is greatly reduced, so that the low-frequency emission performance of small size can be realized. However, the working mode of the slotted ring transducer is single, and the radiation area of the main vibration area is small, which makes it difficult for this type of transducer to realize wideband and high-power radiation.

[0005] The longitudinal bending coupling transducer also uses the coupling of bending vibration mode and longitudinal vibration mode of the transducer to form wideband emission. However, the longitudinal bending coupling transducer has only a single radiation surface, and the radiation area is small and the working frequency band is high. SUMMARY

[0006] The present application aims to overcome the defects of the prior art and provides a multi-slotted ring underwater acoustic transducer.

[0007] Therefore, the present application provides a multi-slotted ring underwater acoustic transducer, which comprises a plurality of axisymmetric periodic vibration units, each of which has the same structure and comprises a slotted metal shell, a longitudinal driving source and an adapter mass. The slotted metal shell is in the shape of a circular arc and has one or more slits. The adapter mass connects the slotted metal shell and the longitudinal driving source and provides a pre-stress to the longitudinal driving source. The slit metal shells of the plurality of vibration units jointly form a circular ring-shaped vibration radiation surface.

[0008] As an improvement of the transducer, the slit metal shell has a certain thickness, which is uniform or non-uniform.

[0009] As an improvement of the transducer, the longitudinal driving source is tangentially distributed along the circumference or radially distributed in a star shape.

[0010] As an improvement of the transducer, when the longitudinal driving source is radially distributed in a star shape, the transducer further comprises a central mass block for connecting all the longitudinal driving sources and providing pre-stress.

[0011] As an improvement of the transducer, the longitudinal driving source is formed by an even number of piezoelectric ceramic sheets polarized along the thickness direction and bonded together, and an electrode sheet is arranged between adjacent ceramic sheets.

[0012] As an improvement of the transducer, the longitudinal driving source is a round bar made of rare earth giant magnetostrictive material, and an excitation coil is wound around the periphery of the round bar, and the excitation coil is enclosed in a closed magnetic circuit made of high magnetic permeability material.

[0013] As an improvement of the transducer, the adapter mass block is in a circular arc shape or a wedge shape, and the adapter angle is 360° / n, where n is the number of vibration units; the adapter mass block is connected to the inner side of the slit metal shell through a screw rod or is integrally formed.

[0014] As an improvement of the transducer, a stress excess area is arranged at the connection between the slit metal shell and the adapter mass block, which can adjust the bending vibration mode frequency while improving the structural strength.

[0015] As an improvement of the transducer, when the transducer is in a flooding structure form, a watertight insulation layer is wrapped outside the longitudinal driving source; when the transducer is in an air-backed structure, a vulcanized vibration film is covered at the slit, and upper and lower end covers are arranged outside the transducer.

[0016] As an improvement of the transducer, the height of the slit metal shell is higher than the height of the adapter mass block, which can increase the effective radiation area while reducing the stiffness and mass of the metal shell.

[0017] Compared with the prior art, the advantages of the present application are: 1. The transducer of the present application utilizes the slits to reduce the stiffness of the metal shell, and the slitted metal shell is arranged in an axisymmetric and periodic manner, thereby increasing the main vibration area while reducing the stiffness of the shell, and realizing low-frequency and high-power radiation. Meanwhile, the vibration mode of the longitudinal driving source is coupled with the bending vibration mode of the shell to form a wideband performance, thereby realizing the characteristics of low frequency, small size, wideband, and high power.

[0018] 2. The present application overcomes the shortcomings of the traditional slitted circular ring transducer, such as small main vibration area and low response, and increases the bending vibration radiation area to several times of the traditional slitted structure, thereby effectively improving the radiation efficiency of the bending vibration mode.

[0019] 3. The present application overcomes the shortcomings of the traditional slitted circular ring transducer, such as single vibration mode and narrow working bandwidth, and realizes wideband emission by coupling the bending vibration mode with the vibration mode of the longitudinal driving source.

[0020] 4. The present application utilizes the advantage of low bending vibration resonance frequency of the slitted shell, thereby realizing small size and low frequency emission.

[0021] 5. The present application can be applied to the fields of low-frequency active sonar, long-range underwater acoustic communication, low-frequency underwater acoustic experiment, and ocean acoustic tomography. BRIEF DESCRIPTION OF DRAWINGS

[0022] Fig. 1(a) is a structural diagram of a vibration unit in Embodiment 1 of the present application, and Fig. 1(b) is a top view of the vibration unit in Embodiment 1 of the present application; Figure 2 is a whole structure diagram of Embodiment 1; Fig. 3(a) is a structural diagram of a vibration unit in Embodiment 2 of the present application, and Fig. 3(b) is a top view of the vibration unit in Embodiment 2 of the present application; Figure 4 is a whole structure diagram of Embodiment 2; Figure 5 is a sending voltage response level curve of Embodiment.

[0023] REFERENCE NUMERALS 1. Longitudinal driving source 2. Switching mass 3. Slitted metal shell 4. Slitted main vibration area 5. Center mass DETAILED DESCRIPTION

[0024] The purpose of the present application is to propose a multi-slitted circular ring underwater acoustic transducer structure, which is different from the traditional slitted circular ring transducer in increasing the main vibration area to improve the radiation efficiency, and adding the driving source vibration mode to widen the working frequency band, thereby realizing the characteristics of low frequency, small size, wideband, and high power.

[0025] The implementation is: comprising a plurality of axisymmetric periodic distribution of vibration units, the vibration unit includes a slotted metal shell, a longitudinal drive source and an adapter mass.

[0026] Specifically comprising: 1. The multi-slotted circular ring transducer provided by the application comprises a plurality of axisymmetric periodic distribution of vibration units, and the overall shape is circular ring. The vibration unit comprises a slotted metal shell, a longitudinal drive source and an adapter mass, the longitudinal drive source and the slotted metal shell are connected by the adapter mass, and the plurality of slotted metal shells jointly form a circular ring vibration surface for outward radiation. The transducer can be in the form of overflow structure or can be enclosed in a shell to be made in the form of air backing.

[0027] 2. The slotted metal shell is in the shape of a circular arc and has a certain thickness. The thickness can be uniform or non-uniform. The circular arc is made to have free vibration at both ends by slitting, thereby forming a bending vibration mode. The inner side is connected to the adapter mass, and a stress excess area is arranged. The outer side is a main vibration area for radiating sound waves outward.

[0028] 3. The height of the slotted metal shell is usually higher than the height of the mass, so as to reduce the stiffness and mass of the metal shell and increase the effective radiation area.

[0029] 4. The arrangement of the longitudinal drive source can be tangential periodic distribution of the slotted metal circular arc shell, or star-shaped distribution with the center of the slotted metal circular arc shell as the center.

[0030] 5. The longitudinal drive source is made of an even number of piezoelectric ceramic sheets. The piezoelectric ceramic sheets are polarized along the thickness direction, and an electrode sheet is arranged between each ceramic.

[0031] 6. The longitudinal drive source can also be replaced by a circular rod made of rare earth giant magnetostrictive material. A group of excitation coils are wound around the periphery of the circular rod, and the excitation coils are enclosed in a closed magnetic circuit made of high magnetic permeability material.

[0032] 7. The adapter mass is a circular arc or wedge-shaped metal block, one side of which is connected to the slotted metal shell and the other side of which is connected to the longitudinal drive source. The angle is related to the number of periodically distributed vibration units. The angle of the adapter mass corresponding to the tangential distribution of the longitudinal drive source needs to be strictly controlled so that it can be completely spliced into a circular ring shape and ensure the continuity of the vibration displacement of the drive source. The central mass block should also be arranged for the star-shaped distribution of the longitudinal drive source to connect all the drive sources.

[0033] The technical solutions of the application will be described in detail below with reference to the drawings and examples.

[0034] Example 1 Example 1 of the application provides a multi-slotted circular ring underwater acoustic transducer.

[0035] The schematic diagrams of the vibration unit and the overall structure are shown in Figure 1(a) and Figure 1(b). Figure 2 Example 1 of a multi-slit circular underwater acoustic transducer: The vibration unit mainly includes a longitudinal drive source 1 distributed tangentially along the circumference, a transfer mass block 2, a slit metal shell 3, and a slit main vibration zone 4. The transducer as a whole is composed of multiple vibration units that are axially symmetrically and periodically distributed, and its shape is circular.

[0036] In this embodiment, the slotted metal shell 3 and the longitudinal drive source 1 are connected by a transfer mass block 2, and a stress transition region is provided at the connection between the transfer mass block 2 and the slotted shell 3. The transfer mass block 2 is shared between two adjacent vibration units. The longitudinal drive source 1 can be composed of a piezoelectric ceramic crystal stack, with prestress applied by a screw between the two transfer mass blocks, or it can be replaced by a round bar made of rare earth magnetostrictive material, with a set of excitation coils wound around the outside of the round bar, and the coils are enclosed in a closed loop made of a high permeability material such as pure iron. The longitudinal drive source 1 is covered with a watertight rubber layer, and the slotted main vibration zone 4 is in an overflow free state.

[0037] Example 2 Example 2 of the present invention provides a multi-slit annular underwater acoustic transducer.

[0038] The schematic diagrams of the vibration unit and the overall structure are shown in Figure 3(a) and Figure 3(b). Figure 4 The multi-slotted annular underwater acoustic transducer mainly comprises a longitudinal drive source 1 arranged in a radial star shape, a transition mass block 2, a slotted metal shell 3, a slotted main vibration zone 4, and a central mass block 5. The transducer as a whole is composed of multiple axisymmetrically periodically distributed vibration units, and its shape is annular.

[0039] In this embodiment, the connection between the slotted metal shell 3 and the longitudinal drive source 1 is the same as in Example 1. The difference is that the prestress of the longitudinal drive source 1 is applied by the transfer mass block 2 and the central mass block 5, and the central mass block 5 is shared among multiple vibration units. Other implementation details are the same as in Example 1.

[0040] Simulation experiment: like Figure 5 The figure shows the simulation results, specifically the voltage response curve of the multi-slit circular underwater acoustic transducer.

[0041] This transducer exhibits broadband performance exceeding one octave. The first resonance peak corresponds to the bending vibration mode of the slotted metal shell, and the second resonance peak corresponds to the longitudinal vibration mode of the longitudinally driven oscillator; together, they constitute the broadband performance. The model corresponding to the simulation results has an outer diameter of φ1000mm and a height of 20mm, and compared to transducers of the same size, it has a lower operating frequency.

[0042] In summary, compared with traditional slotted annular transducers, this invention has a larger radiation area, which can improve radiation efficiency. It utilizes the coupling of shell bending mode and longitudinal vibrating rod vibration mode to form broadband transmission, resulting in a wider operating frequency band. Compared to traditional longitudinal-bending coupled broadband transducers, this invention has a larger radiation area and a smaller size.

[0043] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to the embodiments, those skilled in the art should understand that modifications or equivalent substitutions to the technical solutions of the present invention do not depart from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A multi-slit circular annular underwater acoustic transducer, characterized in that, The transducer comprises multiple axisymmetrically periodically distributed vibration units, each with an identical structure, including a slotted metal shell, a longitudinal drive source, and a transition mass block; wherein, The slotted metal shell is arc-shaped and has one or more slots; The transfer mass block connects the slotted metal shell to the longitudinal drive source and provides prestress to the longitudinal drive source; The slotted metal shells of multiple vibration units together form a circular vibration radiation surface.

2. The multi-slit annular underwater acoustic transducer according to claim 1, characterized in that, The slotted metal shell has a certain thickness, which can be uniform or non-uniform.

3. The multi-slit annular underwater acoustic transducer according to claim 1, characterized in that, The longitudinal drive source is distributed tangentially along the circumference or in a star-shaped distribution along the radial direction.

4. The multi-slit annular underwater acoustic transducer according to claim 3, characterized in that, When the longitudinal drive sources are distributed in a star shape along the radial direction, the transducer also includes a central mass block for connecting all the longitudinal drive sources and providing prestress.

5. The multi-slit annular underwater acoustic transducer according to claim 3, characterized in that, The longitudinal driving source is formed by polarizing and bonding an even number of piezoelectric ceramic sheets along the thickness direction, with electrode sheets provided between adjacent ceramic sheets.

6. The multi-slit annular underwater acoustic transducer according to claim 3, characterized in that, The longitudinal driving source is a cylindrical rod made of rare-earth super magnetostrictive material, with an excitation coil wound around its periphery. The excitation coil is enclosed in a closed magnetic circuit made of high permeability material.

7. The multi-slit annular underwater acoustic transducer according to claim 1, characterized in that, The transition mass block is arc-shaped or wedge-shaped, with a transition angle of 360° / n, where n is the number of vibration units; the transition mass block is connected to the inner side of the slotted metal shell by a screw or integrally formed.

8. The multi-slit annular underwater acoustic transducer according to claim 1, characterized in that, A stress transition area is provided at the connection between the slotted metal shell and the transfer mass block, which is used to adjust the bending vibration mode frequency while improving the structural strength.

9. The multi-slit annular underwater acoustic transducer according to claim 1, characterized in that, When the transducer is an overflow structure, a watertight insulating layer is wrapped around the longitudinal drive source; when the transducer is an air-backed structure, a vulcanized vibration film is covered at the opening, and the transducer is provided with an upper end cover and a lower end cover.

10. The multi-slit annular underwater acoustic transducer according to claim 1, characterized in that, The height of the slotted metal shell is higher than the height of the transfer mass block, which is used to increase the effective radiation area while reducing the stiffness and mass of the metal shell.

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