Transmitting and receiving combined broadband twin transducer

Abstract

The invention discloses a receiving and transmitting combined broadband twin transducer, and belongs to the technical field of underwater sound. The transducer comprises a low-frequency longitudinal vibration unit and a high-frequency longitudinal vibration unit which are axially arranged in parallel, front radiation heads of the low-frequency longitudinal vibration unit and the high-frequency longitudinal vibration unit are of a split complementary structure, and a shared tail mass block is of an integrated structure; the axial length of the low-frequency longitudinal vibration unit is larger than that of the high-frequency longitudinal vibration unit, so that different resonant frequencies are obtained, frequency response complementation is formed, and the working frequency band of the twin transducer is widened. According to the invention, the problem that the existing underwater acoustic transducer cannot have the characteristics of high emission response and high receiving sensitivity on the basis of ensuring the broadband is solved.

Description

Technical Field

[0001] The present invention belongs to the field of underwater acoustic technology, and particularly relates to a monostatic broadband twin transducer. Background Art

[0002] Underwater acoustic transducers are one of the essential key components of underwater acoustic devices. As the front-end sensing components of underwater acoustic devices, they are responsible for transmitting and receiving acoustic signals. With the continuous improvement of the requirements of underwater acoustic applications, characteristics such as wide bandwidth, high sound source level, and high receiving sensitivity of longitudinal vibration transducers have become important development trends.

[0003] For traditional underwater acoustic transducers, due to the deep trough in the response between the resonant frequencies corresponding to the first and second vibration modes, it is difficult to achieve wide-band characteristics. Currently, common means to improve the wide-band characteristics of longitudinal vibration transducers include techniques such as slotted front radiation head technology, dual excitation technology, longitudinal-bending coupling vibration technology, and matching layer technology. Among them, the first three technologies belong to the category of multi-modal coupling technology. This technology mainly uses the superposition of two different vibration modes of the transducer to reduce the depth of the trough in the response between the resonant frequencies corresponding to the two vibration modes of the transducer, thereby achieving the wide-band characteristics of the longitudinal vibration transducer. For example, the working frequency band of 14 - 47 kHz of the longitudinal vibration transducer has been achieved by using dual excitation technology and longitudinal-bending coupling vibration technology, and the maximum fluctuation within the frequency band is ±4 dB. The matching layer technology is to add one or several layers of material layers with certain acoustic impedance characteristics between the radiation surface of the traditional longitudinal vibration transducer and the water medium. Since the characteristic impedance of the matching layer itself is less than that of any component of the transducer and it participates in the vibration of the entire transducer, the second resonant frequency of the transducer is reduced to form two close resonant peaks, thereby achieving the wide-band characteristics of the longitudinal vibration transducer. There is also a disclosed triple-resonant broadband underwater acoustic transducer applying dual excitation technology and matching layer technology, achieving a longitudinal vibration transducer with a transceiver response working bandwidth of 20 kHz - 61 kHz and a fluctuation within the frequency band of -5.2 dB.

[0004] Although the wide-band characteristics of longitudinal vibration transducers can be achieved through the above technical means, with the continuous development of underwater acoustic technology, there are more and more application requirements for long-distance detection and communication in underwater equipment, which requires the transducer to have high sound source level and high receiving sensitivity characteristics. For traditional longitudinal vibration transducers, the coexistence of these characteristics is still a difficult problem. Summary of the Invention

[0005] Technical Problems to be Solved

[0006] To avoid the deficiencies of the prior art, the present invention provides a monostatic broadband twin transducer. The transducer adopts a twin structure design, integrating a low-frequency longitudinal vibration unit and a high-frequency longitudinal vibration unit into one. Through the resonance frequency difference between the two longitudinal vibration units, frequency response complementarity is achieved, broadening the working frequency band of the transducer; through different electrical connection methods between the high-frequency and low-frequency longitudinal vibration units, high transmission response and high receiving sensitivity are achieved on the same device. The present invention solves the problem that current underwater acoustic transducers cannot have both high transmission response and high receiving sensitivity characteristics while ensuring a wide frequency band.

[0007] The technical solution of the present invention is: a monostatic broadband twin transducer, including a low-frequency longitudinal vibration unit and a high-frequency longitudinal vibration unit arranged in parallel axially. The front radiation heads of the two are a split complementary structure, and the shared tail mass block is an integrated structure; the axial length of the low-frequency longitudinal vibration unit is greater than the axial length of the high-frequency longitudinal vibration unit to obtain different resonant frequencies, form frequency response complementarity, and broaden the working frequency band of the twin transducer.

[0008] A further technical solution of the present invention is: the low-frequency longitudinal vibration unit includes a low-frequency front radiation head, a piezoelectric stack, and a tail mass block connected in sequence along the axis. The low-frequency front radiation head is a cuboid structure with a notch.

[0009] A further technical solution of the present invention is: the high-frequency longitudinal vibration unit includes a high-frequency front radiation head, a piezoelectric stack, and a tail mass block connected in sequence along the axis. The cross-sectional shape of the high-frequency front radiation head is the same as the cross-sectional shape of the notch of the low-frequency front radiation head, is flush with the top surface of the low-frequency front radiation head, and there is a gap between the two.

[0010] A further technical solution of the present invention is: the gap between the high-frequency front radiation head and the low-frequency front radiation head is 2 mm.

[0011] A further technical solution of the present invention is: the cross-section of the low-frequency front radiation head is L-shaped, and the cross-section of the high-frequency front radiation head complementary to the inside of the L-shape is square.

[0012] A further technical solution of the present invention is: the tail mass block is a cuboid structure with a step on the top surface. Its step surface is arranged opposite to the high-frequency front radiation head; its first-order top surface is connected to the piezoelectric stack of the low-frequency longitudinal vibration unit, and the second-order top surface is connected to the piezoelectric stack of the high-frequency longitudinal vibration unit; the top surface area of the step is adjustable. By adjusting the first-order and second-order top surface areas, different radiation area ratios are obtained, and thus transducers with different working frequency bands are obtained.

[0013] A further technical solution of the present invention is: the piezoelectric stack includes a plurality of electrode plates and piezoelectric ceramic plates stacked alternately, and insulating gaskets are respectively arranged between the two ends and the front radiation head and the tail mass block.

[0014] A further technical solution of the present invention is that the low-frequency longitudinal vibration unit and the high-frequency longitudinal vibration unit are respectively fixedly connected by two prestressing bolts penetrating the axis, and the prestress is adjusted by the prestressing bolts.

[0015] An electrical connection method in the transmitting acoustic signal stage of a transceiver-integrated broadband twin transducer: electrically connecting the low-frequency longitudinal vibration unit and the high-frequency longitudinal vibration unit in the transceiver-integrated broadband twin transducer in parallel, that is, a high transmitting response can be obtained.

[0016] An electrical connection method in the receiving acoustic signal stage of a transceiver-integrated broadband twin transducer: electrically connecting the low-frequency longitudinal vibration unit and the high-frequency longitudinal vibration unit in the transceiver-integrated broadband twin transducer in series, that is, a high receiving sensitivity can be obtained.

[0017] Beneficial effects

[0018] The beneficial effects of the present invention are as follows: The transceiver-integrated broadband twin transducer of the present invention rationally utilizes the front radiation head design of the high- and low-frequency longitudinal vibration units, the piezoelectric stack size control, and the electrical connection method, effectively solving the technical problem of the coexistence of the broadband, high transmitting response, and high receiving sensitivity characteristics of the underwater acoustic transducer. The specific advantages are as follows:

[0019] 1. The transceiver-integrated broadband twin transducer of the present invention uses a square front radiation head as a whole. Compared with the traditional circular piston radiation head with the same diameter, the radiation area is increased by about 27.32%, which can effectively enhance the acoustic energy radiation of the transducer.

[0020] 2. The transceiver-integrated broadband twin transducer of the present invention utilizes two longitudinal vibration units with different resonant frequencies to achieve frequency response complementarity, effectively broadening the working frequency band of the transducer.

[0021] 3. The transceiver-integrated broadband twin transducer of the present invention adjusts the resonant frequencies of the two transducers by controlling the piezoelectric stack sizes (the number, diameter, and thickness of piezoelectric ceramic sheets) of the high- and low-frequency longitudinal vibration units, and can further reduce the in-band fluctuation of the working frequency band of the transducer.

[0022] 4. The transceiver-integrated broadband twin transducer of the present invention can easily meet the application requirements of different working frequency bands of the transducer by controlling the radiation area ratio of the high- and low-frequency longitudinal vibration units.

[0023] 5. The transceiver-integrated broadband twin transducer of the present invention adopts different electrical connection methods for the high- and low-frequency longitudinal vibration units in different working states. It is connected in parallel in the transmitting state and in series in the receiving state, and can obtain a high transmitting response and a high receiving sensitivity of the transducer, that is, the coexistence of the broadband, high transmitting response, and high receiving sensitivity characteristics of the underwater acoustic transducer is realized.

[0024] 6. The co-located broadband twin transducer of the present invention has a simple structure, low cost, and is easy to arrange in an array. It can be widely used in various underwater equipment for underwater detection, underwater acoustic communication, and other tasks. Description of the Drawings

[0025] Figure 1 is a schematic diagram of the co-located broadband twin transducer of the present invention;

[0026] Figure 2 is a schematic diagram of the low-frequency longitudinal vibration unit of the co-located broadband twin transducer of the present invention;

[0027] Figure 3 is a schematic diagram of the high-frequency longitudinal vibration unit of the co-located broadband twin transducer of the present invention;

[0028] Figure 4 is a diagram of the electrical connection relationship in the transmitting state of the co-located broadband twin transducer of the present invention;

[0029] Figure 5 is a diagram of the electrical connection relationship in the receiving state of the co-located broadband twin transducer of the present invention;

[0030] Figure 6 is a simulation curve diagram of the transmitting voltage response level of the co-located broadband twin transducer of the present invention;

[0031] Figure 7 is a simulation curve diagram of the receiving voltage sensitivity level of the co-located broadband twin transducer of the present invention;

[0032] Description of the reference numerals: 1. Low-frequency front radiation head, 2. Low-frequency electrode plate, 3. Low-frequency piezoelectric ceramic plate, 4. Low-frequency insulating gasket, 5. Tail mass block, 6. High-frequency front radiation head, 7. High-frequency electrode plate, 8. High-frequency piezoelectric ceramic plate, 9. High-frequency insulating gasket, 10. Low-frequency electrode connection wire, 11. Low-frequency insulating sleeve, 12. Low-frequency prestressing bolt, 13. High-frequency electrode connection wire, 14. High-frequency insulating sleeve, 15. High-frequency prestressing bolt. Detailed Embodiments

[0033] The embodiments described below by referring to the drawings are exemplary and are intended to explain the present invention and should not be construed as limiting the present invention.

[0034] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0035] Based on the fact that although the existing underwater acoustic transducers can achieve the broadband characteristics of longitudinal vibration transducers, with the continuous development of underwater acoustic technology, the application requirements for long-distance detection and communication of underwater equipment are increasing, and it is difficult for the same transducer to simultaneously have high source level and high receiving sensitivity characteristics. Therefore, the present invention provides a transceiver-integrated broadband twin transducer, which is composed of two longitudinal vibration units, one is a low-frequency longitudinal vibration unit, and the other is a high-frequency longitudinal vibration unit. The two longitudinal vibration units share a tail mass block; the high- and low-frequency longitudinal vibration units have differences in resonant frequencies, and can easily achieve frequency response complementarity, thereby broadening the working frequency band of the transducer; the high- and low-frequency longitudinal vibration units adopt different electrical connection methods in different working states of the transceiver-integrated broadband twin transducer. In the transmitting state, the high- and low-frequency longitudinal vibration units are connected in parallel electrically, and in the receiving state, the high- and low-frequency longitudinal vibration units are connected in series electrically.

[0036] Currently, the most widely used underwater acoustic transducer is the piezoelectric transducer, which mainly uses the direct and reverse piezoelectric effects of piezoelectric ceramics to realize the conversion of electrical energy and acoustic energy of the transducer. The so-called direct piezoelectric effect means that when a piezoelectric ceramic is subjected to an external force, in addition to deforming and generating internal stress, it will also generate polarization intensity and electric displacement, and the generated polarization intensity and electric displacement are proportional to the strain or stress; the reverse piezoelectric effect means that when a piezoelectric ceramic is subjected to an electric field, in addition to generating polarization intensity and electric displacement, it will also generate strain and stress, and the generated strain and stress are proportional to the electric field strength or electric displacement. Therefore, when the underwater acoustic transducer emits an acoustic signal, it utilizes the reverse piezoelectric effect, and when receiving an acoustic signal, it utilizes the direct piezoelectric effect.

[0037] The following further illustrates the above technical solutions with reference to the drawings and examples:

[0038] In one embodiment, refer to Figure 1As shown in the figure, a transceiver-integrated broadband twin transducer in this embodiment is composed of two longitudinal vibration units, one is a low-frequency longitudinal vibration unit, and the other is a high-frequency longitudinal vibration unit. Specifically, it includes a low-frequency front radiator 1 and a high-frequency front radiator 6, a low-frequency electrode plate 2 and a high-frequency electrode plate 7, a low-frequency piezoelectric ceramic plate 3 and a high-frequency piezoelectric ceramic plate 8, a low-frequency insulating gasket 4 and a high-frequency insulating gasket 9, a low-frequency prestressing bolt 12 and a high-frequency prestressing bolt 15, and a tail mass block 5. Among them, the high- and low-frequency longitudinal vibration units share a tail mass block 5.

[0039] In one embodiment, referring to Figure 2 and Figure 3 , the connection methods and implementation methods of the high- and low-frequency longitudinal vibration units are the same. Here, the low-frequency longitudinal vibration unit is taken as an example: the low-frequency front radiator 1, the low-frequency electrode plate 2, the low-frequency piezoelectric ceramic plate 3, the low-frequency insulating gasket 4, and the tail mass block 5 are coaxially connected through the low-frequency prestressing bolt 12, and an appropriate prestressing force needs to be applied. A low-frequency insulating sleeve 11 is sleeved outside. The low-frequency electrode plate 2 and the low-frequency piezoelectric ceramic plate 3 are cross-bonded. The number of low-frequency piezoelectric ceramic plates 3 is an even number, and the number of low-frequency electrode plates 2 is one more than that of the piezoelectric ceramic plates 3, so as to form a piezoelectric crystal stack. The low-frequency insulating gasket 4 is bonded to both ends of the piezoelectric crystal stack. The polarities of two adjacent low-frequency piezoelectric ceramic plates 3 are opposite, and the same-sex low-frequency electrode plates 2 of each piezoelectric crystal stack are connected in parallel through the low-frequency electrode connection wire 10.

[0040] In one embodiment, referring to Figure 2 shown in the figure, the front radiator 1 of the low-frequency longitudinal vibration unit has an L-shaped cross-section, and the front radiator 6 of the high-frequency longitudinal vibration unit has a square cross-section. There is a certain gap between the two radiators, and they form a square radiator of the transceiver-integrated broadband twin transducer, which can maximize the radiation area in a limited space. Compared with the traditional circular piston radiator with the same diameter, the radiation area is increased by about 27.32%, which can effectively enhance the sound energy radiation of the transducer.

[0041] In one embodiment, the total length of the front radiator 1 of the low-frequency longitudinal vibration unit and its piezoelectric crystal stack is greater than the total length of the front radiator 6 of the high-frequency longitudinal vibration unit and its piezoelectric crystal stack. The tail mass block 5 is designed in a stepped shape. The first step is connected to the piezoelectric crystal stack of the low-frequency longitudinal vibration unit, and the second step is connected to the piezoelectric crystal stack of the high-frequency longitudinal vibration unit.

[0042] In one embodiment, according to different application requirements, by adjusting the sizes of the piezoelectric crystal stacks of the high- and low-frequency longitudinal vibration units (the number, diameter, and thickness of the low-frequency piezoelectric ceramic plates 3 and the high-frequency piezoelectric ceramic plates 8), the resonant frequencies of the two longitudinal vibration units can be adjusted, and the in-band fluctuation in the working frequency band of the transceiver-integrated broadband twin transducer can be further reduced; by adjusting the radiation area ratio of the high- and low-frequency longitudinal vibration units, different working frequency band ranges of the transceiver-integrated broadband twin transducer can be realized.

[0043] In one embodiment, referring to Figure 4 As shown in Figure 4 , the electrical connection method of the transmitting acoustic signal stage of a co-located broadband twin transducer: the low-frequency longitudinal vibration unit and the high-frequency longitudinal vibration unit in the co-located broadband twin transducer are electrically connected in parallel, so that the transducer obtains a low driving voltage and high transmitting characteristics, thereby improving its sound source level.

[0044] In one embodiment, referring to Figure 5 As shown in Figure 5 , the electrical connection method of the receiving acoustic signal stage of a co-located broadband twin transducer: the low-frequency longitudinal vibration unit and the high-frequency longitudinal vibration unit in the co-located broadband twin transducer are electrically connected in series, so that the transducer obtains a high induced voltage, thereby improving its receiving sensitivity.

[0045] In one embodiment, referring to Figure 6 and Figure 7 As shown in Figure 6 and Figure 7 , by simulating a co-located broadband twin transducer in the working frequency range of 18 kHz - 42 kHz, both its transmitting voltage response level and receiving voltage sensitivity level meet the -3 dB fluctuation. At this time, the maximum transmitting voltage response level of the transducer is 140.4 dB, and the maximum receiving voltage sensitivity level is -172.4 dB.

[0046] In one embodiment, the specific assembly process of the co-located broadband twin transducer is as follows:

[0047] (1) First, assemble the low-frequency longitudinal vibration unit. Use epoxy resin to cross-bond the low-frequency electrode sheet 2 and the low-frequency piezoelectric ceramic sheet 3 together to complete the preparation of the piezoelectric crystal stack. Then, bond the low-frequency insulating gasket 4 to both ends of the piezoelectric crystal stack. At this time, it is necessary to ensure that the low-frequency electrode sheet 2, the low-frequency piezoelectric crystal stack 3, and the low-frequency insulating gasket 4 are coaxial, as Figure 2 shown in Figure 2 ;

[0048] (2) Use the low-frequency prestress bolt 12 to fix the low-frequency front radiator 1 and the tail mass block 5 to both ends of the piezoelectric crystal stack after bonding the low-frequency insulating gasket 4. The low-frequency prestress bolt 12 is sleeved with a low-frequency insulating sleeve 11, and an appropriate prestress is applied to the low-frequency prestress bolt 12, as Figure 2 shown in Figure 2 ;

[0049] (3) Assemble the high-frequency front radiator 6, the high-frequency electrode sheet 7, the high-frequency piezoelectric ceramic sheet 8, the high-frequency insulating gasket 9, the tail mass block 5, the high-frequency prestress bolt 15, and the high-frequency insulating sleeve 14 of the high-frequency longitudinal vibration unit in the same steps, as Figure 3 shown in Figure 3 ;

[0050] (4) Place the assembled co-located broadband twin transducer into a drying oven for drying. After drying, connect the same-sex high-frequency electrode sheets 2 and the same-sex low-frequency electrode sheets 7 of the high- and low-frequency longitudinal vibration units in parallel, asFigure 2 , 3 as shown;

[0051] (5) Finally, vulcanize and encapsulate the transceiver integrated broadband twin transducer that has completed the lead connection.

[0052] The main functions achieved by the transceiver integrated broadband twin transducer of the present invention include:

[0053] The transceiver integrated broadband twin transducer in this embodiment takes into account both the functions of transmitting and receiving underwater acoustic waves; by using the L-shaped front radiation head 1 of the low-frequency longitudinal vibration unit and the square front radiation head 6 of the high-frequency longitudinal vibration unit, the radiation area of the transceiver integrated broadband twin transducer is maximized; by using the high- and low-frequency longitudinal vibration units, frequency response complementarity is achieved, enabling the transceiver integrated broadband twin transducer to obtain broadband characteristics; by using different electrical connection methods for the high- and low-frequency longitudinal vibration units, high transmission response and high reception sensitivity of the transceiver integrated broadband twin transducer are achieved.

[0054] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention.

Claims

1. A broadband twin transducer with a combined transmitter and receiver, characterized in that: It comprises a low-frequency longitudinal vibration unit and a high-frequency longitudinal vibration unit which are axially connected in parallel. The front radiation heads of the two are split complementary structures, and the shared tail mass block is an integrated structure. The axial length of the low-frequency longitudinal vibration unit is greater than the axial length of the high-frequency longitudinal vibration unit to obtain a differential resonant frequency, form frequency response complementation, and broaden the working frequency band of the twin transducers.

2. According to claim 1, a broadband twin transducer with combined transmission and reception, characterized in that: The low-frequency longitudinal vibration unit comprises a low-frequency front radiation head, a piezoelectric crystal stack, and a tail mass block which are sequentially connected along the axial direction. The low-frequency front radiation head is a rectangular parallelepiped structure with a notch.

3. According to claim 2, a broadband twin transducer with combined transmission and reception, characterized in that: The high-frequency longitudinal vibration unit includes a high-frequency front radiation head, a piezoelectric crystal stack, and a tail mass block connected in sequence along the axial direction. The cross-sectional shape of the high-frequency front radiation head is consistent with the notch cross-sectional shape of the low-frequency front radiation head, and is arranged flush with the top surface of the low-frequency front radiation head, with a gap left between the two.

4. The broadband twin transducer for transmitting and receiving according to claim 3, characterized in that: The gap between the high-frequency front radiating head and the low-frequency front radiating head is 2 mm.

5. The broadband twin transducer with combined transmission and reception according to claim 3, characterized in that: The cross section of the low-frequency front radiating head is L-shaped, and the cross section of the high-frequency front radiating head complementary to the inner side of the L-shape is square.

6. The broadband twin transducer for transmitting and receiving according to claim 1, characterized in that: The tail mass block is a rectangular structure with steps on the top surface, and the step surface is arranged opposite to the high-frequency front radiation head; the first-order top surface is connected to the piezoelectric crystal stack of the low-frequency longitudinal vibration unit, and the second-order top surface is connected to the piezoelectric crystal stack of the high-frequency longitudinal vibration unit; the top surface area of ​​the step is adjustable, and by adjusting the first-order and second-order top surface areas, different radiation area ratios are obtained, thereby obtaining transducers with different working frequency bands.

7. The broadband twin transducer for transmitting and receiving according to claim 1, characterized in that: The piezoelectric crystal stack comprises a plurality of electrode sheets and piezoelectric ceramic sheets which are stacked in an interlaced manner, and insulating gaskets are respectively arranged between the two ends and the front radiation head and the tail mass block.

8. The broadband twin transducer for transmitting and receiving according to claim 1, characterized in that: The low-frequency longitudinal vibration unit and the high-frequency longitudinal vibration unit are respectively fixedly connected by two prestressed bolts penetrating the axial direction, and the prestress is adjusted by the prestressed bolts.

9. An electrical connection method for transmitting acoustic signals of the broadband twin transducer combined with a transmitter and receiver according to any one of claims 1 to 8, characterized in that: By electrically connecting the low-frequency longitudinal vibration unit and the high-frequency longitudinal vibration unit in the transmitting-receiving combined broadband twin transducer in parallel, a high transmission response can be obtained.

10. An electrical connection method for receiving acoustic signals of the broadband twin transducer combined with a transmitter and receiver according to any one of claims 1 to 8, characterized in that: By electrically connecting the low-frequency longitudinal vibration unit and the high-frequency longitudinal vibration unit in the transmitting and receiving combined broadband twin transducer in series, high receiving sensitivity can be obtained.

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