A multi-mode broadband high-power directional emission longitudinal vibration underwater acoustic transducer

Abstract

The present invention discloses a multi-mode broadband high-power directional emission longitudinal vibration underwater acoustic transducer, which relates to the field of underwater acoustic transducers, including a longitudinal vibration transducer vibrator with a flexible ring, a square cylindrical structure resonance cavity shell, a decoupling support structure and a tail sealing end cover; the longitudinal vibration transducer vibrator with a flexible ring is composed of a front cover plate with a flexible ring, a piezoelectric ceramic crystal pile, a stress screw and a rear cover plate. Utilizing the liquid cavity coupling principle, a square cylindrical structure liquid coupling cavity is designed at the front end of the front cover plate of the longitudinal vibration transducer vibrator with a flexible ring, which will generate a new resonance resonance peak between the two resonances of the double cover plate longitudinal vibration transducer. The beneficial effects of the present invention are: the frequency band is wide, and broadband emission can be achieved in the medium and low frequency range of 2.5 to 7.5 Hz; the backward radiation within the working frequency band is small, and the unidirectional radiation capability is strong; the structural size can be adjusted according to the actual engineering needs, and it has the ability to work in deep water, good adaptability and flexible array.

Description

Technical Field

[0001] The invention relates to the field of underwater acoustic transducers, and in particular to a multi-mode broadband high-power directional emission longitudinal vibration underwater acoustic transducer. Background Art

[0002] Longitudinal vibration transducer, also known as Tonpilz transducer, is widely used in the field of underwater acoustic transducers due to its simple structure and stable working performance. The transmission working bandwidth of the transducer affects the overall performance of the active sonar, such as the amount of information in the echo, the transmission rate of the signal, and the anti-reverberation ability.

[0003] Active sonar is a device that emits sound waves into the water. In order to make the sound waves propagate farther and achieve better emission effects, multiple underwater acoustic transducers are usually used to form a transmitting sound array to achieve high-power directional emission. Active sonar transmitting sound arrays usually use planar and cylindrical sound arrays, and some use spherical arrays. The longitudinal vibration transducer is the most commonly used array unit, which has the characteristics of good adaptability and flexible array.

[0004] Most traditional longitudinal vibration transducers are single vibration mode transducers with strong directional radiation capability, but the response frequency band is generally narrow, making it difficult to achieve broadband operation. To increase the operating frequency band of the transducer, it can only be achieved by superimposing other vibration modes to obtain dual resonance. The extended modes that can usually be superimposed include the bending vibration mode of the front cover plate, the vibration mode of the matching layer, the coupling of dual excitation vibration modes, and the vibration mode of the mass block in the flexible ring. Dual-mode dual-resonance technology is an important technology for broadening the frequency band of longitudinal vibration transducers, but the broadband that can be obtained by such dual-mode longitudinal vibration transducers in the medium and low frequency bands is also limited, and the resonance point distribution and amplitude adjustment of the two resonance modes are difficult. There is usually a response concave point between the two resonance frequencies, resulting in large fluctuations in the emission response, usually above 5dB, and low electroacoustic efficiency and insufficient sound power at the response concave point. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and to provide a multi-mode broadband high-power directional emission longitudinal vibration underwater acoustic transducer, which has the advantages of simple structure, easy use, safety and reliability.

[0006] The objective of the present invention is achieved through the following technical solutions: This multi-modal broadband high-power directional longitudinal vibration underwater acoustic transducer comprises a resonance cavity shell, a longitudinal vibration transducer vibrator with a flexible ring, a front cover plate rear decoupling support structure, a rear cover plate rear decoupling support structure and a tail sealing end cover, wherein the resonance cavity shell is a cylindrical structure which is open at the top and bottom and through inside, and comprises a lower cylinder, the upper diameter of the lower cylinder is narrowed and extends upward to form an upper cylinder; the longitudinal vibration transducer vibrator with a flexible ring comprises a front cover plate with a flexible ring, a piezoelectric ceramic crystal pile, a rear cover plate and a stress screw, the front cover plate with a flexible ring is a structure which is trumpet-shaped at the bottom and has a circular ring-shaped cavity at the top, the rear cover plate is arranged at the upper part of the front cover plate with the flexible ring, and a piezoelectric ceramic crystal pile is arranged between the two, the stress screw passes through the rear cover plate and the piezoelectric ceramic crystal pile, and is fixed The upper part of the front cover plate with a flexible ring is used to apply prestress to the piezoelectric ceramic crystal pile, and make the front cover plate with a flexible ring, the piezoelectric ceramic crystal pile and the rear cover plate coaxial; the vibrator of the longitudinal vibration transducer with a flexible ring is placed in the inner cavity of the resonance cavity shell, the lower part of the front cover plate with a flexible ring is in contact and sealed with the inner wall of the lower cylinder, and a liquid cavity resonance area is formed between the inner wall of the lower cylinder and the upper surface of the front cover plate with a flexible ring, and the liquid cavity depth is controlled by the rear decoupling support structure of the front cover plate arranged in the liquid cavity resonance area; the upper part of the front cover plate with a flexible ring, the piezoelectric ceramic crystal pile and the rear cover plate extend into the upper cylinder, and the three are fixedly positioned at the center of the resonance cavity shell by the rear decoupling support structure of the rear cover plate arranged in the upper cylinder; a tail sealing end cover is fixedly installed at the end of the upper cylinder to seal the resonance cavity shell, and the piezoelectric ceramic crystal pile is electrically connected to the tail sealing end cover.

[0007] As a preferred technical solution, the resonance cavity shell is made of corrosion-resistant metal material.

[0008] As a preferred technical solution, the lower portion of the lower cylinder expands outward to form a square head.

[0009] As a preferred technical solution, an O-ring sealing groove is provided along the circumferential direction at the contact sealing point between the front cover plate with the flexible ring and the inner wall of the lower cylinder for embedding and installing the O-ring A.

[0010] As a preferred technical solution, the piezoelectric ceramic crystal stack is composed of an even number of piezoelectric ceramic elements, metal electrode sheets and piezoelectric ceramic gaskets at both ends bonded to each other. The piezoelectric ceramic elements are polarized along the thickness direction, and the polarization directions of two adjacent sheets are opposite. The positive and negative output wires are led out through the metal electrode sheets, and the piezoelectric ceramic gaskets use non-polarized piezoelectric ceramic elements to achieve electrical isolation.

[0011] As a preferred technical solution, one end of the stress screw has a hexagonal boss fixed on the rear cover plate; the other end of the stress screw has a thread and is threadedly connected to the upper part of the front cover plate with the flexible ring.

[0012] As a preferred technical solution, the tail sealing end cover is provided with a watertight connector mounting hole or a watertight cable vulcanization interface.

[0013] As a preferred technical solution, the tail sealing end cover is sealed with the resonance cavity housing through an O-ring B.

[0014] As a preferred technical solution, the tail sealing end cover is made of corrosion-resistant metal material.

[0015] The beneficial effects of the present invention are:

[0016] 1. The frequency band is wide, and broadband transmission can be carried out in the medium and low frequency range of 2.5 to 7.5 Hz;

[0017] 2. Small backward radiation within the working frequency band and strong unidirectional radiation capability;

[0018] 3. The structural dimensions can be adjusted according to actual engineering needs. It has deep-water working capabilities, good adaptability and flexible deployment. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural schematic diagram of the present invention.

[0020] Figure 2 Schematic diagram of the structure of the resonant cavity shell.

[0021] Figure 3 It is a schematic diagram of the structure of the vibrator of the longitudinal vibration transducer with a flexible ring.

[0022] Figure 4 This is the transmission response curve of the oscillator of the longitudinal vibration transducer with a flexible ring.

[0023] Figure 5 This is the sending response curve of the present invention.

[0024] Figure 6 It is the directivity diagram of each working frequency of the present invention.

[0025] Explanation of the reference numerals in the accompanying drawings: resonance cavity shell 1, upper cylinder 1-1, lower cylinder 1-2, square head 1-3, front cover plate with flexible ring 2, piezoelectric ceramic crystal pile 3, rear cover plate 4, stress screw 5, rear decoupling support structure of the front cover plate 6, rear decoupling support structure of the rear cover plate 7, tail sealing end cover 8, O-ring A9, O-ring B10. DETAILED DESCRIPTION

[0026] The present invention will be described in detail below with reference to the accompanying drawings:

[0027] Example: As shown in the attached Figure 1As shown, this multi-modal broadband high-power directional transmitting longitudinal vibration underwater acoustic transducer includes a longitudinal vibration transducer vibrator with a flexible ring, a resonance cavity shell 1, a front cover plate rear decoupling support structure 6, a rear cover plate rear decoupling support structure 7 and a tail sealing end cover 8; the longitudinal vibration transducer vibrator with a flexible ring is composed of a front cover plate 2 with a flexible ring, a piezoelectric ceramic crystal stack 3, a stress screw 5 and a rear cover plate 4.

[0028] like Figure 2 As shown, the resonance cavity shell 1 is made of corrosion-resistant metal materials such as stainless steel or titanium alloy. The resonance cavity shell 1 is a cylindrical structure that is open at the top and bottom and has a through interior. It includes a lower cylinder 1-2. The upper diameter of the lower cylinder 1-2 is narrowed and extends upward to form an upper cylinder 1-1. The lower part of the lower cylinder 1-2 expands outward to form a square head 1-3. The square head 1-3 has a certain thickness and acts as a metal anti-sound baffle. The size of the square surface is matched with the transducer array requirements to meet the dense use of the transducers when they are arrayed.

[0029] like Figure 3 As shown, the front cover plate 2 with a flexible ring is made of a metal material with a lower density, such as a hard aluminum alloy material. The lower end is in the shape of a large cylinder plus a small cone (trumpet-shaped). An O-ring sealing groove is made in the circumferential direction of the large cylindrical end for inserting the O-ring A9. A liquid cavity resonance area is formed between the upper surface of the large cylinder (the front cover plate 2 with a flexible ring) and the inner wall of the lower cylinder 1-2; the flexible ring part is a circular cavity structure connected to the small end of the cone, and the other end of the flexible ring part is a small cylindrical cover plate with a threaded hole in the center, which can be achieved by metal welding or hollowing out the cylindrical metal material. The small cylindrical cover plate is bonded to the piezoelectric ceramic gasket of the piezoelectric ceramic crystal stack 3, and a step with the same diameter as the ceramic crystal stack is cut out for positioning when bonding with the ceramic crystal stack, and the threaded hole is used to install a fixed stress screw 5. The inner diameter of the lower cylinder 1-2 cooperates with the O-ring A9 of the front cover plate 2 with a flexible ring to form an independent liquid cavity interval. The front cover plate 2 with a flexible ring can also be wrapped and isolated in the lower cylinder 1-2 by polyurethane or rubber material to achieve a watertight effect and prevent the liquid in the liquid cavity interval from entering the vibrator of the longitudinal vibration transducer with a flexible ring.

[0030] The piezoelectric ceramic crystal stack 3 is composed of an even number of piezoelectric ceramic elements, metal electrode sheets and piezoelectric ceramic gaskets at both ends. The piezoelectric ceramic elements are polarized in the thickness direction, and the polarization directions of two adjacent pieces are opposite. The positive and negative output wires are led out through the metal electrode sheets, and the piezoelectric ceramic gaskets use non-polarized piezoelectric ceramic elements to achieve electrical isolation.

[0031] The rear cover plate 4 is made of a metal material with a high density such as steel. It is a cylindrical structure with a central through hole. Its diameter is slightly smaller than the inner diameter of the upper cylinder 1-1. A step with the same diameter as the ceramic crystal pile is cut at one end of the rear cover plate 4 for positioning when bonding with the piezoelectric ceramic crystal pile 3. A step is reserved at the other end of the rear cover plate 4 for positioning with the rear decoupling support structure 7 of the rear cover plate.

[0032] The stress screw 5 is a metal rod with a thread at one end and a hexagonal boss at the other end. The material is modulated high-strength structural steel. The stress screw 5 passes through the central through hole of the rear cover plate 4 and the piezoelectric ceramic crystal stack 3. The threaded end of the stress screw 5 is connected to the threaded hole of the front cover plate 2 with a flexible ring, and prestress is applied to the piezoelectric ceramic crystal stack 3. After force is applied, the front cover plate 2 with a flexible ring, the piezoelectric ceramic crystal stack 3 and the rear cover plate 4 are required to be coaxial.

[0033] There is one decoupling support structure at the rear end of each of the front cover plate 2 with a flexible ring and the rear cover plate 4, which is made of non-metallic decoupling material, such as hard foam material or cork rubber material, and is used to support and fix the position of the longitudinal vibration transducer vibrator with a flexible ring in the resonance cavity shell 1. The front cover plate rear decoupling support structure 6 is placed in the liquid cavity resonance area formed between the upper surface of the front cover plate 2 with a flexible ring and the inner wall of the lower cylinder 1-2, which can limit the position of the front cover plate 2 with a flexible ring to penetrate into the resonance cavity shell 1, and is used to customize the liquid cavity height of the liquid cavity resonance area formed by the front cover plate 2 with a flexible ring and the resonance cavity shell 1. Adjusting the liquid cavity height can change the frequency position and response size of the liquid cavity resonance; the rear cover plate rear decoupling support structure 7 is placed in the upper cylinder 1-1 to fix the distance of the rear cover plate 4 inside the resonance cavity shell 1, ensuring that the longitudinal vibration transducer vibrator with a flexible ring is located at the center of the resonance cavity shell 1 after installation, and will not be deflected.

[0034] The tail sealing end cap 8 is made of corrosion-resistant metal materials such as stainless steel or titanium alloy, and is sealed with the inner diameter of the resonance cavity housing 1 (upper cylinder 1-1) through an O-ring B10, and is fixed to the upper end face of the resonance cavity housing 1 with bolts, so that the transducer has deep water working characteristics. The tail sealing end cap 8 is electrically connected to the positive and negative outputs of the piezoelectric ceramic crystal stack 3 through wires, and the cable is led out through the watertight connector installation hole reserved on the tail sealing end cap 8 or the watertight cable vulcanization interface.

[0035] The basic theoretical basis of the present invention is: using the liquid cavity coupling principle, a square cylindrical liquid coupling cavity is designed at the front end of the front cover of the cylindrical longitudinal vibration transducer, so that a new resonance peak will be generated between the two resonances of the double cover longitudinal vibration transducer. Although this resonance will have a certain impact on the two longitudinal vibrations, the overall emission voltage response can be flattened by optimizing the coupling cavity height. The coupling cavity is to add a square cylindrical metal shell structure to the periphery of the radiation surface of the front cover of the transducer, and extend it backward into a cylindrical shell to wrap the entire transducer to form a whole, which not only provides the effect of expanding the frequency band, but also can use the strength of the metal structure to achieve pressure resistance. The square part also plays the role of a metal anti-sound baffle, so that the transducer has deep water performance and unidirectional radiation capability.

[0036] Reference Figure 4 , 56. Compared with the classic longitudinal vibration transducer and the traditional Janus transducer in terms of working mechanism, the innovative points of the present invention include: first, compared with the single-mode and dual-mode longitudinal vibration transducers, the transducer of the present invention realizes multi-mode three-resonance broadband operation; second, compared with the traditional Janus transducer, the transducer of the present invention has the unique unidirectional radiation characteristics of the longitudinal vibration transducer, which can be better applied to the array design of the transducer array, and the mutual radiation effect is small; third, the coupled resonant cavity structure adopts a new square circular hole structure, which can be used as a liquid coupling cavity to expand the bandwidth, and can also be used as a metal anti-sound baffle to optimize the low-frequency directivity, and extends backward into a cylindrical shell with deep-water working ability.

[0037] It is understandable that, for those skilled in the art, any equivalent replacement or change to the technical solution and inventive concept of the present invention should fall within the protection scope of the claims attached to the present invention.

Claims

1. A multi-mode broadband high-power directional emission longitudinal vibration underwater acoustic transducer, characterized in that: The invention comprises a resonant cavity shell (1), a longitudinal vibration transducer vibrator with a flexible ring, a front cover plate rear decoupling support structure (6), a rear cover plate rear decoupling support structure (7) and a tail sealing end cover (8), wherein the resonant cavity shell (1) is a cylindrical structure with upper and lower openings and an inner through hole, and comprises a lower cylinder (1-2), wherein the upper diameter of the lower cylinder (1-2) is narrowed and extends upward to form an upper cylinder (1-1); the longitudinal vibration transducer vibrator with a flexible ring comprises a front cover plate with a flexible ring (2), The invention relates to a piezoelectric ceramic crystal stack (3), a rear cover plate (4) and a stress screw (5); the front cover plate (2) with a flexible ring is a structure with a trumpet-shaped lower part and a circular ring-shaped cavity at the upper part; the rear cover plate (4) is arranged on the upper part of the front cover plate (2) with the flexible ring, and a piezoelectric ceramic crystal stack (3) is arranged between the two; the stress screw (5) passes through the rear cover plate (4) and the piezoelectric ceramic crystal stack (3), and is fixed on the upper part of the front cover plate (2) with the flexible ring, and is used to apply a stress to the piezoelectric ceramic crystal stack (3). Stress is generated, and the front cover plate with a flexible ring (2), the piezoelectric ceramic crystal pile (3) and the rear cover plate (4) are made coaxial; the vibrator of the longitudinal vibration transducer with a flexible ring is placed in the inner cavity of the resonance cavity shell (1); the lower part of the front cover plate with a flexible ring (2) is in contact and sealed with the inner wall of the lower cylinder (1-2); and a liquid cavity resonance region is formed between the inner wall of the lower cylinder (1-2) and the upper surface of the front cover plate with a flexible ring (2); and a decoupling support structure (6) is provided behind the front cover plate in the liquid cavity resonance region. ) to control the depth of the liquid cavity; the upper part of the front cover plate (2) with a flexible ring, the piezoelectric ceramic crystal pile (3) and the rear cover plate (4) extend into the upper cylinder (1-1), and the three are fixedly positioned at the center of the resonance cavity shell (1) through a rear decoupling support structure (7) of the rear cover plate disposed in the upper cylinder (1-1); a tail sealing end cover (8) is fixedly installed at the end of the upper cylinder (1-1) to seal the resonance cavity shell (1), and the piezoelectric ceramic crystal pile (3) is electrically connected to the tail sealing end cover (8).

2. The multi-mode broadband high-power directional emission longitudinal vibration underwater acoustic transducer according to claim 1 is characterized in that: The resonance cavity shell (1) is made of corrosion-resistant metal material.

3. The multi-mode broadband high-power directional emission longitudinal vibration underwater acoustic transducer according to claim 1 is characterized in that: The lower part of the lower cylinder (1-2) expands outwards to form a square head (1-3).

4. The multi-mode broadband high-power directional emission longitudinal vibration underwater acoustic transducer according to claim 1 is characterized in that: An O-ring sealing groove is provided along the circumferential direction at the contact sealing position between the front cover plate (2) with the flexible ring and the inner wall of the lower cylinder (1-2), for embedding and installing an O-ring A (9).

5. The multi-mode broadband high-power directional emission longitudinal vibration underwater acoustic transducer according to claim 1 is characterized in that: The piezoelectric ceramic crystal stack (3) is composed of an even number of piezoelectric ceramic elements, metal electrode sheets and piezoelectric ceramic gaskets at both ends that are bonded to each other. The piezoelectric ceramic elements are polarized along the thickness direction, and the polarization directions of two adjacent pieces are opposite. Positive and negative output wires are led out through the metal electrode sheets, and the piezoelectric ceramic gaskets use non-polarized piezoelectric ceramic elements to achieve electrical isolation.

6. The multi-mode broadband high-power directional emission longitudinal vibration underwater acoustic transducer according to claim 1 is characterized in that: One end of the stress screw (5) is provided with a hexagonal boss and is fixed on the rear cover plate (4); the other end of the stress screw (5) is provided with a thread and is threadedly connected to the upper part of the front cover plate (2) with a flexible ring.

7. The multi-mode broadband high-power directional emission longitudinal vibration underwater acoustic transducer according to claim 1 is characterized in that: The tail sealing end cover (8) is provided with a watertight connector mounting hole or a watertight cable vulcanization interface.

8. The multi-mode broadband high-power directional emission longitudinal vibration underwater acoustic transducer according to claim 1 is characterized by: The tail sealing end cover (8) is sealed with the resonance cavity housing (1) via an O-ring B (10).

9. The multi-mode broadband high-power directional emission longitudinal vibration underwater acoustic transducer according to claim 1 is characterized in that: The tail sealing end cover (8) is made of corrosion-resistant metal material.

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