Low-frequency broadband high-power parallel drive flextensional transducer

Abstract

The invention discloses a low-frequency broadband high-power parallel driving flextensional transducer which comprises a flextensional shell and a driving unit. The flextensional shell comprises second radiation ends located at the two ends and a first radiation end connected between the two second radiation ends in the long axis direction. The second radiation end is in a concave arc shape; the driving unit is installed in the shell and is in rigid connection with the inner wall of the second radiation end, the excitation direction of the driving unit is consistent with the tangent line of the concave arc in the horizontal direction, and parallel driving is achieved. According to the structure, a flextensional mode node is moved to a driving end, so that sound field counteracting in a first-order mode anti-phase region is effectively inhibited, and the electro-acoustic conversion efficiency is improved; and meanwhile, the phase difference between the first-order mode and the second-order mode is regulated and controlled to 180 degrees through the shell configuration, so that the working bandwidth is effectively expanded. The invention has the characteristics of low frequency, small size, high power and broadband, and is suitable for a high-performance underwater acoustic emission system.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of underwater systems and operating equipment, and particularly relates to a low-frequency wide-band large-power parallel driving bending and stretching transducer. BACKGROUND

[0002] The underwater acoustic transducer is a core device for realizing the conversion of underwater electric acoustic energy, and is widely used in various underwater systems and operating equipment, such as underwater communication, detection, navigation and remote control operating platform. With the rapid development of modern sonar technology and the continuous expansion of the application of underwater acoustics in the fields of marine resource development, underwater security and protection, deep sea exploration and the like, the requirements for the working performance of the underwater acoustic transducer are increasingly improved. At present, the emission transducer with the characteristics of low frequency, wide band, small size and large power for deep water environment has become the key development direction of underwater acoustic emission technology. Among them, the low-frequency large-power acoustic signal can realize longer distance propagation in water, effectively improving the range of underwater systems; and the wide working bandwidth helps to improve the information transmission rate, reduce the error rate, and enhance the reliability and real-time performance of underwater operating equipment communication.

[0003] However, under the severe constraints of low frequency and miniaturization, the electro-acoustic conversion efficiency of the bending and stretching transducer is significantly limited, and the typical working mode is the first-order quadrupole bending and stretching vibration mode, which has the problem of mutual cancellation of the sound field in the positive and negative radiation areas, resulting in low far-field acoustic radiation efficiency.

[0004] In addition, realizing wide-band emission is the key to improving the information transmission rate and communication reliability, and the first-order and second-order bending modes of the traditional IV-type bending and stretching transducer are difficult to effectively couple due to the phase difference of 0 degrees, which seriously restricts the application of multi-mode wide-band technology. SUMMARY

[0005] The present application provides a low-frequency wide-band large-power parallel driving bending and stretching transducer to overcome the above technical problems.

[0006] In order to achieve the above purpose, the technical scheme of the present application is as follows: A low-frequency wide-band large-power parallel driving bending and stretching transducer, comprising a bending and stretching shell and a driving unit; the bending and stretching shell comprises a first radiation end connected between two second radiation ends and the second radiation ends located at both ends along the long axis direction; the second radiation end is a concave circular arc shape; The driving unit is arranged inside the bending and stretching shell and is rigidly connected with the inner wall of the second radiation end; the excitation direction of the driving unit is parallel to the tangent direction of the concave circular arc shape in the horizontal direction, thereby realizing parallel driving.

[0007] Further, the driving unit comprises a piezoelectric stack structure bonded by an even number of piezoelectric elements, the piezoelectric elements are piezoelectric single crystal sheets or piezoelectric ceramic sheets, and the piezoelectric single crystal sheets or piezoelectric ceramic sheets are connected in parallel in the circuit.

[0008] Further, the drive unit comprises a rare earth giant magnetostrictive rod; the rare earth giant magnetostrictive rod is peripherally sleeved with a coil former; and a coil is wound on the coil former.

[0009] Further, the rare earth giant magnetostrictive rod is respectively provided with a permanent magnet piece at each end.

[0010] Further, the drive unit is provided with a transition block at each axial end; and a stress screw rod penetrates through the entire drive unit and sequentially passes through one end transition block, piezoelectric stack structure and the other end transition block to jointly form a vibrator assembly.

[0011] Further, the longitudinal dimension of the vibrator assembly is greater than the inner space dimension of the driving end of the bending and stretching shell, the bending and stretching shell is pre- elastically deformed, the vibrator assembly is pressed into and fixed in the bending and stretching shell to form a pre-stressed assembly structure.

[0012] Further, the inner wall of the first radiation end of the bending and stretching shell is provided with a rubber airbag; the drive unit is externally coated with a rubber waterproof layer; and a cable passes through the rubber waterproof layer and is sealingly connected therewith.

[0013] Further, the bending and stretching shell is made of any one of stainless steel, steel, titanium alloy, aluminum alloy, glass fiber or carbon fiber.

[0014] Further, the first radiation end is an outward convex circular arc shape, the outward convex circular arc shape is smoothly connected to the inward concave circular arc shape and geometrically tangent at the connection.

[0015] Beneficial effects: (1) The parallel driving bending and stretching transducer provided by the application is low-frequency, wide-band and high-power, the outer end part of the long axis of the original bending and stretching shell is replaced by an inward concave circular arc shape, the connection is geometrically tangent to the radiation end, and a new type of bending and stretching shell configuration is formed. The structure successfully migrates one vibration node of the bending mode to the driving end in combination with the parallel driving mode, significantly reduces the volume displacement of the anti-phase radiation area under the first-order bending vibration mode, effectively suppresses the positive and negative cancellation effect of the sound field, and greatly improves the electro-acoustic conversion efficiency.

[0016] (2) The structure design effectively changes the vibration characteristics of the shell, migrates one vibration node of the second-order bending vibration mode to the driving end, and changes the displacement zero-crossing point to the tangent zero point. This measure adjusts the phase difference between the first-order and second-order bending vibration modes from 0 degrees to 180 degrees, thereby creating favorable conditions for multi-modal coupling. Not only does it significantly slow down the decay rate of the first-order bending mode resonance peak, but it also greatly expands the working bandwidth of the transducer by forming a second resonance peak with the second-order mode, effectively improving its wide-band emission capability in the low-frequency band.

[0017] (3) The low-frequency broadband high-power parallel drive bending and tensioning transducer of the present invention has a simple and compact structure and is easy to implement.

[0018] (4) The low-frequency broadband high-power parallel drive bending transducer of the present invention can be applied to underwater acoustic detection, countermeasures, communication, measurement and marine resource exploration. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the traditional Type IV bending and tensioning transducer.

[0021] Figure 2 This is a schematic diagram of the structure of the low-frequency broadband high-power parallel drive bending and tensioning transducer of the present invention.

[0022] Figure 3 This is a cross-sectional view of the low-frequency broadband high-power parallel drive bending transducer of the present invention.

[0023] Figure 4 This is a comparison of the simulated emission voltage response curves of the low-frequency broadband high-power parallel drive bending transducer of the present invention and a traditional type IV bending transducer of the same size and resonant frequency. In the figure: 1: Elliptical tension shell; 2: Tension shell; 3: Transition block; 4: Piezoelectric stack structure; 5: Stress screw; 6: Rubber airbag; 7: Rubber waterproof layer; 8: Cable. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] This embodiment provides a low-frequency broadband high-power parallel-drive bending transducer, including a bending housing 2 and a drive unit. For example... Figure 2 and Figure 3Its shell is based on the traditional elliptical tension shell 1, with the outer end of the long axis replaced by a concave arc structure. The tension shell 2 includes second radiating ends located at both ends and a first radiating end connecting the two second radiating ends along the long axis; the second radiating ends are concave arc-shaped. The driving unit is located inside the bending shell 2 and is rigidly connected to the inner wall of the second radiating end; the excitation direction of the driving unit is parallel to the tangent direction of the concave arc in the horizontal direction, thereby realizing parallel driving.

[0026] This invention employs a parallel driving method to effectively relocate a vibration node of the bending mode to the driving end (i.e., the connection face between the driving unit and the inner wall of the second radiation end). This significantly reduces the volume displacement of the anti-phase radiation region under the first-order bending vibration mode, thereby suppressing the positive and negative cancellation effects of the acoustic field and greatly improving the electroacoustic conversion efficiency of the Type IV bending transducer. This advantage is particularly prominent under the stringent design conditions of low frequency and small size. Simultaneously, by replacing the outer end of the major axis of the traditional elliptical shell with a concave arc, the phase difference between the first and second-order bending vibration modes is successfully adjusted from 0 degrees to 180 degrees, creating favorable conditions for multi-mode coupling. Based on this, the introduction of multi-mode coupling technology not only effectively slows down the decay rate of the first-order resonance peak but also significantly expands the transducer's operating bandwidth by exciting a second resonance peak formed by the second-order mode, achieving synergistic optimization of low frequency, wide bandwidth, and high efficiency.

[0027] Furthermore, the driving unit includes a piezoelectric stack structure 4 formed by bonding an even number of piezoelectric elements, wherein the piezoelectric elements are piezoelectric single crystal wafers or piezoelectric ceramic wafers, and the piezoelectric single crystal wafers or piezoelectric ceramic wafers are connected in parallel in the circuit.

[0028] In Embodiment 1, the driving unit includes a piezoelectric stack structure 4 formed by bonding an even number of piezoelectric single crystal wafers. The single crystal wafers are Φ16mm*3mm in size and are connected in parallel in the circuit. Using a piezoelectric stack structure composed of an even number of piezoelectric single crystal wafers in parallel not only achieves a higher electromechanical coupling coefficient and strain output, significantly enhancing the low-frequency high-power driving capability, but also reduces the operating voltage requirement and improves system safety and compatibility with the driving circuit. Simultaneously, the symmetrical arrangement of the even number of wafers effectively counteracts internal bending moments, improves stress distribution, and extends device lifespan.

[0029] Furthermore, in embodiment 2, the driving unit includes a piezoelectric stack structure 4 formed by bonding an even number of piezoelectric ceramic sheets. The ceramic sheets have dimensions of Φ70mm*Φ30mm*6mm and are connected in parallel in the circuit. Using a parallel stacked structure of piezoelectric ceramic sheets ensures both good power output and better economic practicality.

[0030] Furthermore, in Embodiment 3, the driving unit includes a rare-earth super magnetostrictive rod; a coil frame is fitted around the outer periphery of the rare-earth super magnetostrictive rod; a coil is wound on the coil frame; and a permanent magnet is installed at each end of the rare-earth super magnetostrictive rod. Utilizing the high energy density and fast response characteristics of the super magnetostrictive material under magnetic field, stronger driving force output can be achieved in the low-frequency range; the permanent magnets at both ends provide a stable static bias magnetic field, ensuring that the material operates in the optimal linear region, improving conversion efficiency and dynamic stability; and the coil is wound on a dedicated frame, ensuring excitation uniformity and enhancing heat dissipation and insulation performance.

[0031] Furthermore, transition blocks 3 are provided at both ends of the pressure drive unit along its axial direction; the stress screw 5 runs through the entire drive unit, passing sequentially through one end transition block 3, the piezoelectric stack structure 4, and the other end transition block 3, together forming the oscillator assembly. In this embodiment, the transition blocks 3 are preferably made of titanium alloy.

[0032] Furthermore, the longitudinal dimension of the oscillator assembly is larger than the internal space dimension of the drive end of the tension housing 2. When assembling the transducer, pressure is applied to both ends of the short shaft of the tension housing 2 to increase the length of the long shaft. The oscillator assembly is placed in the tension housing 2 and the pressure is released. At this time, the oscillator assembly is fixed in the tension housing 2 by prestress and is rigidly connected to the transducer housing.

[0033] Furthermore, the tension shell 2 is made of any one of stainless steel, steel, titanium alloy, aluminum alloy, glass fiber, or carbon fiber. In this embodiment, the tension shell 2 is preferably made of titanium alloy, and its total length is approximately 760 mm.

[0034] Furthermore, the transducer employs a rubber airbag 6 to provide an air backing for the radiating end face, and a rubber waterproof layer 7 is installed to insulate the piezoelectric crystal stack, preventing performance degradation or failure of the piezoelectric stack structure 4 due to moisture or short circuits. The cable 8 is led out from the rubber waterproof layer 7. The rubber airbag 6, acting as an air backing for the radiating end face, effectively isolates the external water pressure from suppressing the vibration of the housing. Simultaneously, the rubber waterproof layer 7 tightly encloses the piezoelectric crystal stack, achieving excellent electrical insulation and moisture-proof sealing, preventing breakdown or short circuits under high-voltage operating conditions. The cable 8 is reliably led out through the rubber waterproof layer 7, ensuring the safety and sealing integrity of signal and power transmission.

[0035] Furthermore, the first radiating end is a convex arc shape, which smoothly transitions to the concave arc shape and is geometrically tangent at the connection point, making the overall outline smooth, soft, and aesthetically pleasing.

[0036] When the transducer is working, an AC load is applied to the piezoelectric stack structure 4 via cable 8. Due to the piezoelectric effect of the crystal, the entire piezoelectric stack structure 4 undergoes longitudinal stretching vibration. Through the mechanical coupling between the drive unit and the bending shell 2, different vibration modes of the bending shell 2 are excited in different frequency ranges. The broadband transmission of the transducer is achieved by coupling the first and second order bending vibration modes. The simulation curves of the low-frequency broadband high-power parallel-driven bending transducer and the same size and operating frequency are compared as shown in the figure. Figure 4 As shown. The transmit voltage response refers to the ratio of the product of the sound pressure at a certain reference distance from the equivalent sound center and the reference distance in the far field of the transmitting transducer at a certain frequency and in a specified direction, to the voltage applied to the input terminal. Figure 4 The low-frequency broadband high-power parallel-driven bending transducer exhibits a transmit voltage response of 139 dB at 200 Hz. This performance surpasses that of the traditional Type IV bending transducer, with a significantly larger operating bandwidth, enabling low-frequency broadband, small-size, high-power transmission from the bending transducer.

[0037] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A low frequency broadband high power bending and stretching transducer driven in parallel, characterized in that: The application relates to a bending and stretching shell (2) and a driving unit; the bending and stretching shell (2) comprises second radiation ends at two ends and a first radiation end connected between the two second radiation ends along a long axis direction; the second radiation end is an inner concave circular arc shape; The driving unit is arranged in the bending and stretching shell (2) and is rigidly connected with the inner wall of the second radiation end; the excitation direction of the driving unit is parallel to the tangent direction of the inner concave circular arc shape in the horizontal direction, so that parallel driving is realized.

2. A low frequency wideband high power bending and stretching transducer driven in parallel according to claim 1; characterized in that: The driving unit comprises a piezoelectric stack structure (4) formed by bonding even piezoelectric elements; the piezoelectric elements are piezoelectric single crystal pieces or piezoelectric ceramic pieces; the piezoelectric single crystal pieces or piezoelectric ceramic pieces are connected in parallel on an electric circuit.

3. The low-frequency broadband high-power bending-tension transducer driven in parallel according to claim 1, characterized in that: The driving unit comprises a rare earth super-magnetic-striction rod; a coil former is sleeved on the outer periphery of the rare earth super-magnetic-striction rod; a coil is wound on the coil former.

4. A low frequency wideband high power bending and stretching transducer driven in parallel according to claim 3, characterized in that: One piece of permanent magnetic piece is arranged at each end of the rare earth super-magnetic-striction rod.

5. A low frequency wideband high power bending-tension transducer driven in parallel according to claim 1, characterized in that: Transition blocks (3) are arranged at the axial two ends of the driving unit; a stress screw rod (5) penetrates through the whole driving unit and sequentially passes through one end transition block (3), the piezoelectric stack structure (4) and the other end transition block (3), and together forms a vibrator assembly.

6. A low frequency wideband high power bending mode parallel drive transducer according to claim 5, characterized in that: The longitudinal dimension of the vibrator assembly is greater than the inner space dimension of the driving end of the bending and stretching shell (2); the vibrator assembly is pressed into and fixed in the bending and stretching shell (2) by pre-elastic deformation of the bending and stretching shell (2), so as to form a pre-stress assembly structure.

7. The low frequency broadband high power bending mode parallel drive transducer of claim 1, wherein: The inner wall of the first radiation end of the bending and stretching shell (2) is provided with a rubber air bag (6); the driving unit is covered with a rubber waterproof layer (7); and a cable (8) penetrates through the rubber waterproof layer (7) and is sealingly connected with the rubber waterproof layer (7).

8. The low frequency broadband high power bending-tension transducer driven in parallel according to claim 1, characterized in that: The bending and stretching shell (2) is made of any one of stainless steel, steel, titanium alloy, aluminum alloy, glass fiber or carbon fiber.

9. The low frequency broadband high power bending-tension transducer driven in parallel according to claim 1, characterized in that: The first radiation end is an outer convex circular arc shape which is smoothly connected with the inner concave circular arc shape and geometrically tangent at the connecting position.

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