A low-frequency piezoelectric transducer based on closed-loop cooperative extended vibration modes

Abstract

This application belongs to the field of underwater acoustic transducer technology and discloses a low-frequency piezoelectric transducer based on a closed-loop cooperative expansion vibration mode. The transducer includes multiple circumferentially arranged vibration units, which are connected end-to-end through a displacement amplification component to form a closed-loop structure. Each vibration unit includes a piezoelectric drive component and a connecting component. The piezoelectric drive component generates mechanical vibration, and the displacement amplification component converts the mechanical vibration into radial displacement output. The radial displacements generated by each vibration unit form a continuous mechanical coupling relationship through the closed-loop structure. Under the mechanical constraint of the closed loop, each vibration unit maintains synchronous phase and forms a unified vibration degree of freedom, thereby driving the entire closed-loop structure to generate radial expansion and contraction motion, forming a closed-loop cooperative expansion vibration mode. This invention combines low-frequency operating capability, large radiation area, and deep-sea pressure resistance, and is applicable to fields such as deep-sea acoustic sources, underwater acoustic communication, underwater detection, marine observation, and marine engineering equipment.

Description

Technical Field

[0001] This application belongs to the field of underwater acoustic transducer technology, specifically relating to a low-frequency piezoelectric transducer based on closed-loop cooperative expansion vibration mode, which is suitable for long-term operation in the deep sea and can be applied to deep-sea sound sources, underwater acoustic communication, underwater detection, marine observation, marine engineering equipment and deep-sea resource development. Background Technology

[0002] Low-frequency, high-power underwater acoustic transducers are crucial core components for marine exploration, underwater acoustic communication, marine observation, and marine engineering equipment. Currently, common low-frequency piezoelectric transducers mainly include Tonpilz transducers, tension transducers, and interlocking ring transducers. Tonpilz transducers offer advantages such as high power capacity and mature technology, but achieving low-frequency operation typically requires a large axial dimension, making miniaturization difficult. Tension transducers amplify displacement through elastic structures, achieving lower operating frequencies within a smaller size. However, their vibration relies primarily on the bending deformation of local elastic structures, which can lead to stress concentration, frequency drift, and decreased structural stability in the high hydrostatic pressure environment of the deep sea. Interlocking ring transducers have a large radiation area, but relatively small vibration displacement, and suffer from significant acoustic short-circuit effects and complex deep-sea pressure-resistant design.

[0003] Furthermore, even if multiple vibration units in the existing technology are arranged in a ring, they are essentially still a combination of multiple independent vibrating bodies. There is a lack of design concept for forming a unified vibration degree of freedom by using closed-loop mechanical constraints between adjacent units, and a new vibration mode that transforms from local displacement amplification to overall radial breathing motion has not yet been formed.

[0004] Therefore, existing technologies struggle to simultaneously achieve low-frequency operation capability, large radiation area, high pressure resistance, and long-term reliable operation in the deep sea. This contradiction is particularly pronounced under conditions of continuous operation at full ocean depth. Summary of the Invention

[0005] The purpose of this application is to overcome the shortcomings of existing technologies that cannot simultaneously achieve low-frequency operation capability, large radiation area, high water pressure resistance and long-term reliable operation capability in the deep sea.

[0006] To achieve the above objectives, this application proposes a low-frequency piezoelectric transducer based on closed-loop cooperative expansion vibration modes. The transducer is a regular polygonal closed-loop structure, a circular arc segmented closed-loop structure, or a continuous circular closed-loop structure formed by connecting multiple vibration units through a displacement amplification component. Each of the vibration units includes a piezoelectric drive assembly, a first connection assembly, and a second connection assembly; The piezoelectric drive assembly includes two piezoelectric drive elements; the piezoelectric drive elements are used to generate mechanical vibrations. The first connecting component is used to support two piezoelectric driving elements; the first connecting component includes a polygonal metal block and metal screws extending to both sides; the screws on both sides, when combined with the metal block, form a set bending angle; The second connecting component is used to connect the vibration unit and the displacement amplification component; The displacement amplification component is used to convert mechanical vibration into displacement output along the radial direction of the closed-loop structure, while reducing the frequency through bending vibration.

[0007] As an improvement to the above-mentioned transducer, the displacement amplification component is composed of one or more combinations of an arc-shaped elastic plate structure, a curved beam structure, an arch-shaped elastic structure, or a flexible hinge structure.

[0008] As an improvement to the above-mentioned transducer, the piezoelectric driving element is one or more of the following: piezoelectric crystal stack, piezoelectric stack, piezoelectric ceramic assembly, or piezoelectric composite actuator.

[0009] As an improvement to the aforementioned transducer, the vibration unit further includes a prestressing loading mechanism; The prestressing loading mechanism is used to apply preload to the piezoelectric drive element.

[0010] As an improvement to the transducer described above, the two piezoelectric drive elements are connected in series on the screws on both sides of the first connecting assembly via their central through holes; all contact points between the first and second connecting assemblies and the two piezoelectric drive elements are isolated by insulating components.

[0011] As an improvement to the aforementioned transducer, the prestressing loading mechanism is a prestressing locking nut, which cooperates with the screw of the first connecting assembly and the second connecting assembly to apply a preload to the piezoelectric drive element.

[0012] As an improvement to the above-mentioned transducer, the regular polygonal closed-loop structure includes a regular hexagon, a regular octagon, a regular decagon, or other regular polygonal structures.

[0013] As an improvement to the above-mentioned transducer, the transducer further includes a drive wire for driving the piezoelectric drive element.

[0014] Compared with existing technologies, the advantages of this application are: 1. Propose novel vibration modes; For the first time, a closed-loop collaborative expansion vibration mode is proposed, realizing the conversion of multiple local displacement amplification units into overall radial breathing motion.

[0015] 2. Achieving a balance between low frequency and miniaturization; By utilizing a closed-loop coordinated vibration mechanism to increase the equivalent vibration size, low-frequency operation can be achieved at a smaller structural scale; 3. Increase the effective radiation area; The overall closed-loop structure participates in vibration, effectively improving the sound radiation area and radiation efficiency; 4. Improve deep-sea pressure resistance; This creates a natural closed-loop force flow path, reducing the proportion of local bending stress. 5. Develop new technological routes; Establish a new deep-sea piezoelectric transducer technology that combines low frequency, large radiation area, and deep-sea pressure resistance. Attached Figure Description

[0016] Figure 1 The diagram shown is a schematic representation of the overall structure of Embodiment 1. Figure 2 The diagram shown is a schematic of a single vibration unit structure. Figure 3 The diagram shows the formation mechanism of closed-loop cooperative expansion vibration modes. Figure 4 The diagram shown is a schematic representation of an embodiment of a segmented closed-loop structure. Figure 5 The diagram shows a closed-loop force flow path under the action of deep-sea hydrostatic pressure.

[0017] Attached image labels: 1. Piezoelectric drive assembly 2. Displacement amplification assembly 3. First connecting component; 4. Second connecting component 5. Prestressing loading mechanism; 6. Vibration unit 7. Closed-loop structure 8. Drive wire Detailed Implementation

[0018] The technical solution of this application will be described in detail below with reference to the accompanying drawings.

[0019] This application provides a low-frequency piezoelectric transducer based on a closed-loop cooperative expansion vibration mode. By constructing a closed-loop mechanical coupling structure composed of multiple vibration units, multiple locally displaced amplification vibration units form a unified overall radial breathing motion under the closed-loop constraint, thereby establishing a new transducer vibration mode—the closed-loop cooperative expansion mode. Using this vibration mode, the local displacement amplification effect can be converted into an overall expansion vibration effect, thus simultaneously achieving deep-sea, low-frequency, and high-power operating capabilities.

[0020] This closed-loop mechanical coupling structure consists of multiple vibration units connected end-to-end via connecting components and a displacement amplification component. Each vibration unit includes a piezoelectric drive component and a connecting component. The piezoelectric drive component generates mechanical vibration. The connecting component connects the vibration unit to the displacement amplification component. The displacement amplification component converts the mechanical vibration into radial displacement output.

[0021] The overall radial expansion and contraction motion of the closed-loop mechanically coupled structure (hereinafter referred to as the closed-loop structure) constitutes the closed-loop cooperative expansion vibration mode. The radial displacement generated by each vibration unit is transmitted to the adjacent vibration unit through the connecting components; each vibration unit forms a continuous mechanical coupling relationship in the closed-loop structure; under the closed-loop mechanical constraint, each vibration unit maintains synchronous phase and forms a unified vibration degree of freedom, thereby driving the entire closed-loop structure to generate radial expansion and contraction motion.

[0022] The closed-loop structure is a regular polygonal closed-loop structure, a segmented circular arc closed-loop structure, or a continuous circular ring closed-loop structure, formed by connecting multiple vibration units through a displacement amplification component. The regular polygonal closed-loop structure includes regular hexagons, regular octagons, regular decagons, or other regular polygonal structures. Each vibration unit includes a piezoelectric drive component, a first connecting component, a second connecting component, and a prestressing loading mechanism. The first connecting component supports two piezoelectric drive elements. The first connecting component has a certain bending angle, so that the two piezoelectric drive elements form a certain included angle after connection, which is equal to the interior angle of the closed-loop structure. The second connecting component is used to fix the piezoelectric drive component and connects it to the displacement amplification component through radial bolts, pins, welding, bonding, integrated machining, or other connection methods that can achieve mechanical load transmission; bolt connection is preferred. The piezoelectric drive component includes two piezoelectric drive elements. The piezoelectric drive elements are one or more of piezoelectric crystal stacks, piezoelectric stacks, piezoelectric ceramic groups, and piezoelectric composite actuators. The prestressing loading mechanism uses a prestressed locking nut. The displacement amplification component is composed of one or more combinations of arc-shaped elastic plate structure, curved beam structure, arch-shaped elastic structure, and flexible hinge structure.

[0023] The overall radial expansion and contraction motion of the closed-loop structure constitutes the closed-loop coordinated expansion vibration mode. A piezoelectric drive component generates mechanical vibration. A displacement amplification component converts the mechanical vibration into a displacement output along the radial direction of the closed-loop structure. Adjacent vibration units are connected by a second connecting component and the displacement amplification component, forming a continuous mechanical constraint relationship. The radial displacements generated by each vibration unit are coupled together through the closed-loop structure, forming a unified vibration degree of freedom. Under the action of the closed-loop mechanical constraints, each vibration unit maintains a synchronous phase relationship and moves collaboratively, thereby driving the entire closed-loop structure to generate radial expansion and contraction motion.

[0024] Example 1 like Figure 1 and Figure 2As shown, this embodiment provides a deep-sea low-frequency piezoelectric transducer based on closed-loop cooperative expansion vibration modes. The transducer includes six vibration units 6 and six displacement amplification components 2.

[0025] Six vibration units 6 and six displacement amplification components 2 are sequentially and interconnected to form a regular hexagonal closed-loop structure 7. Each vibration unit 6 includes: a piezoelectric drive component 1, a first connecting component 3, a second connecting component 4, and a prestressing loading mechanism 5. The piezoelectric drive component 1 includes two piezoelectric drive elements capable of generating mechanical vibration. Preferably, the piezoelectric drive elements are one or more of a piezoelectric crystal stack, a piezoelectric stack, a piezoelectric ceramic assembly, or a piezoelectric composite actuator. The piezoelectric drive component 1 is arranged along the side length direction of the corresponding vibration unit 6. The first connecting component 3 consists of a metal block and metal screws extending to both sides; the screws on both sides, combined with the metal block, form a 120-degree bending angle. The two piezoelectric drive elements are connected in series with the screws on both sides of the first connecting component 3 via their central through-hole, and then fixedly connected via the second connecting component 4 and the prestressing loading mechanism 5. The prestressing loading mechanism 5 is a prestressing locking nut, which, through the screws on both sides of the first connecting component 3 and the second connecting component 4, jointly applies an axial preload to the piezoelectric drive elements. The contact points between the first connecting assembly 3 and the two piezoelectric drive elements, as well as the through-hole between the two piezoelectric drive elements and the screws, are isolated by an insulator. The second connecting assembly 4 is also isolated from the piezoelectric drive elements by an insulator. Because the two screws of the first connecting assembly 3 have a 120-degree bending angle, the two piezoelectric drive elements have a 120-degree included angle, causing the six vibration units 6 to form a regular hexagonal structure. The displacement amplification assembly 2 adopts an arc-shaped elastic plate structure. Both ends of the arc-shaped elastic plate are connected to the second connecting assembly 4, thus connecting the arc-shaped elastic plate to the piezoelectric drive assembly 1. When the piezoelectric drive assembly 1 operates, it generates axial expansion and contraction displacement, which is converted into radial amplified displacement by the displacement amplification assembly 2. The drive wire 8 connects to each piezoelectric drive element, serving as the wire that drives the piezoelectric drive element.

[0026] When any vibration unit 6 generates radial displacement, it transmits constraint force to the adjacent vibration unit 6 through the second connecting component 4. Since all vibration units 6 form a closed-loop structure, a closed-loop mechanical coupling relationship is formed between each vibration unit 6. Under the constraint of the closed-loop structure, each vibration unit 6 maintains the same phase relationship and moves synchronously. Ultimately, this drives the entire closed-loop structure to generate overall radial expansion and contraction motion. This overall breathing motion constitutes the closed-loop coordinated expansion vibration mode.

[0027] Example 2 like Figure 3As shown, this embodiment is basically the same as Embodiment 1, except that the number of vibration units 6 is eight. The eight vibration units 6 are connected end-to-end through the second connecting component 4 and the displacement amplification component 2 to form a regular octagonal closed-loop structure. Each vibration unit 6 still uses the piezoelectric drive component 1, the first connecting component 3, the second connecting component 4, and the prestressing loading mechanism 5. During operation, each vibration unit 6 forms a mechanical coupling through the closed-loop structure. Under the constraint of the closed loop, an overall radial breathing motion is formed. Its vibration mechanism is the same as that of Embodiment 1. This embodiment shows that the present invention is not limited to a hexagonal structure. For other regular polygonal closed-loop structures composed of multiple vibration units 6, a closed-loop cooperative expansion vibration mode can also be formed.

[0028] Example 3 like Figure 4 As shown, multiple vibration units 6 are uniformly arranged along the circumference. Adjacent vibration units 6 are connected by a second connecting component 4 and a displacement amplification component 2 to form a segmented circular loop structure. As the number of segments increases, the overall structure gradually approaches a continuous circular ring structure. During operation, the radial displacements generated by each vibration unit 6 are coupled to each other through the closed-loop structure. Under the constraint of the closed loop, each vibration unit 6 forms a unified overall vibration degree of freedom. Ultimately, this drives the entire circular ring structure to generate synchronous radial expansion and contraction motions, thereby forming a closed-loop cooperative expansion vibration mode. This embodiment illustrates that the present invention is also applicable to segmented circular loop structures and continuous circular ring structures.

[0029] Analysis of deep-sea pressure resistance mechanism: like Figure 5 As shown, when the transducer is deployed in a deep-sea environment, external hydrostatic pressure acts uniformly on the outer surface of the closed-loop structure. For the closed-loop structure formed by this invention, the external radial pressure first acts on the connecting components. Subsequently, it is transmitted along the closed-loop structure to form a continuous closed force flow path. In this process, the radial pressure is gradually converted into circumferential compressive force flow. Therefore, the proportion of compressive stress in the load borne by the displacement amplification component is significantly increased.

[0030] Unlike traditional bending transducers where the displacement amplification structure primarily bears bending stress, the closed-loop structure of this invention helps reduce local stress concentration. Simultaneously, the continuously closed force flow path helps maintain the overall structural stability. Under the hydrostatic pressure of the deep sea, the closed-loop cooperative expansion vibration mode can remain essentially intact, thus meeting the requirements for long-term deep-sea operation.

[0031] The core of this invention lies not in employing a specific displacement amplification structure, but in constructing a closed-loop mechanical coupling system. When the piezoelectric drive assembly operates, each vibration unit first generates local mechanical vibration. This vibration is then converted into radially amplified displacement by the displacement amplification assembly. The radial displacement generated by each vibration unit transmits constraint effects to adjacent vibration units through the connecting assembly. Since all vibration units form a closed-loop structure, a unified mechanical coupling relationship is established between the units. Under the closed-loop constraint, each vibration unit maintains the same phase relationship and moves synchronously. Ultimately, this drives the entire closed-loop structure to produce overall radial expansion and contraction motion.

[0032] This invention defines the overall respiratory motion as a closed-loop coordinated expansion vibration mode. Through this vibration mode, the local displacement amplification effect is transformed into an overall expansion vibration effect.

[0033] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit it. Although this application 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 this application do not depart from the spirit and scope of the technical solutions of this application, and should all be covered within the scope of the claims of this application.

Claims

1. A low-frequency piezoelectric transducer based on closed-loop cooperative extended vibration modes, characterized in that, The transducer is a regular polygonal closed-loop structure, a circular arc segmented closed-loop structure, or a continuous circular closed-loop structure formed by connecting multiple vibration units through a displacement amplification component. Each of the vibration units includes a piezoelectric drive assembly, a first connection assembly, and a second connection assembly; The piezoelectric drive assembly includes two piezoelectric drive elements; the piezoelectric drive elements are used to generate mechanical vibrations. The first connecting component is used to support the two piezoelectric drive elements; the first connecting component includes a polygonal metal block and metal screws extending to both sides; the screws on both sides, when combined with the metal block, form a set bending angle; The second connecting component is used to connect the vibration unit and the displacement amplification component; The displacement amplification component is used to convert mechanical vibration into displacement output along the radial direction of the closed-loop structure, while reducing the frequency through bending vibration.

2. The low-frequency piezoelectric transducer based on closed-loop cooperative expansion vibration mode according to claim 1, characterized in that: The displacement amplification component is composed of one or more combinations of an arc-shaped elastic plate structure, a curved beam structure, an arch-shaped elastic structure, or a flexible hinge structure.

3. The low-frequency piezoelectric transducer based on closed-loop cooperative expansion vibration mode according to claim 1, characterized in that: The piezoelectric driving element is one or more of the following: piezoelectric crystal stack, piezoelectric stack, piezoelectric ceramic assembly, or piezoelectric composite actuator.

4. The low-frequency piezoelectric transducer based on closed-loop cooperative expansion vibration mode according to claim 1, characterized in that: The vibration unit also includes a prestressing loading mechanism; The prestressing loading mechanism is used to apply preload to the piezoelectric drive element.

5. The low-frequency piezoelectric transducer based on closed-loop cooperative expansion vibration mode according to claim 4, characterized in that: The two piezoelectric drive elements are connected in series on the screws on both sides of the first connecting assembly via their central through holes; all contact points between the first and second connecting assemblies and the two piezoelectric drive elements are isolated by insulating components.

6. The low-frequency piezoelectric transducer based on closed-loop cooperative expansion vibration mode according to claim 5, characterized in that: The prestressing loading mechanism is a prestressing locking nut, which cooperates with the screw of the first connecting component and the second connecting component to apply prestress to the piezoelectric drive element.

7. The low-frequency piezoelectric transducer based on closed-loop cooperative expansion vibration mode according to claim 1, characterized in that: The regular polygonal closed-loop structure includes regular hexagons, regular octagons, regular decagons, or other regular polygonal structures.

8. The low-frequency piezoelectric transducer based on closed-loop cooperative expansion vibration mode according to claim 1, characterized in that: The transducer also includes a drive wire for driving the piezoelectric drive element.

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