阅读说明：本技术 一种级联式压电陶瓷水声换能器 (Cascade piezoelectric ceramic underwater acoustic transducer ) 是由 滕舵 李亚天 朱宁 于 2019-09-29 设计创作，主要内容包括：本发明公开了一种级联式压电陶瓷水声换能器,由前辐射头、级联单元、配重壳体、预应力螺栓和输出电缆线组成,前辐射头和配重壳体位于换能器两端,中间为多个级联单元串接在一起,级联单元由两组压电晶堆并排放置并通过预应力螺栓与弯曲圆盘紧密连接接成一体。配重壳体具有水密和换能器尾部配重的作用。输出电缆线通过配重壳体将压电晶堆的引线连接至外激励源。换能器横向小尺寸的前提下,充分利用了纵向空间,结合压电晶堆的纵向振动和弯曲圆盘的弯曲振动的合理耦合,实现换能器的低频率、小尺寸和轻质量特征。换能器具有结构简单、性能稳定的特点,可广泛应用于水下探测、水声通信领域,适用于搭载各类水下运载体进行水中作业。(The invention discloses a cascade piezoelectric ceramic underwater acoustic transducer, which consists of a front radiation head, cascade units, a counterweight shell, a prestressed bolt and an output cable, wherein the front radiation head and the counterweight shell are positioned at two ends of the transducer, the middle part of the transducer is provided with a plurality of cascade units which are connected in series, and each cascade unit is formed by arranging two groups of piezoelectric crystal stacks side by side and tightly connecting the piezoelectric crystal stacks with a bent disc into a whole through the prestressed bolt. The counterweight shell has the functions of water tightness and counterweight of the tail part of the transducer. An output cable connects the lead of the piezoelectric crystal stack to an external excitation source through the counterweight housing. On the premise of small transverse size of the transducer, the longitudinal space is fully utilized, and the characteristics of low frequency, small size and light weight of the transducer are realized by combining the reasonable coupling of the longitudinal vibration of the piezoelectric crystal stack and the bending vibration of the bending disk. The transducer has the characteristics of simple structure and stable performance, can be widely applied to the fields of underwater detection and underwater acoustic communication, and is suitable for carrying various underwater carriers to carry out underwater operation.)

1. A cascade piezoelectric ceramic underwater acoustic transducer comprises a front radiation head, a cascade unit, a counterweight shell and an output cable, and is characterized in that the counterweight shell comprises a waterproof cover, a tail mass block and a fastening bolt; the cascade unit comprises a bending disc, a piezoelectric crystal stack, a spring gasket and a prestressed bolt; the piezoelectric crystal stack comprises an insulating gasket, an electrode plate, a piezoelectric ceramic piece, an insulating sleeve and an electrode connecting wire; the front radiation head and the counterweight shell are respectively positioned at two ends of the transducer, the front radiation head is of a horn-shaped structure, the opening end of the front radiation head is outward favorable for outward radiation of sound energy, a circumferential groove is formed in the throat part of the front radiation head for mounting a sealing ring, the sealing ring is tightly matched with the waterproof cover to form a watertight structure, and the throat part of the front radiation head is connected with the cascade unit through a prestressed bolt;

The cascade unit is a plurality of cascade units, the cascade units are connected in series into a whole and positioned between the front radiation head and the counterweight shell, each cascade unit is formed by arranging two groups of piezoelectric crystal stacks side by side and is tightly connected with the bending disc through a prestressed bolt, each group of piezoelectric crystal stacks is formed by electrically connecting and mechanically connecting and bonding an even number of piezoelectric ceramic plates in series according to positive and reverse polarization directions, the waterproof cover is connected with the tail mass block through a fastening bolt, and the output cable penetrates through the counterweight shell and an electrode connecting wire of the piezoelectric crystal stacks to be connected to an external excitation source;

The piezoelectric crystal pile is formed by bonding piezoelectric ceramic pieces with holes in the middle, the polarization directions of the adjacent piezoelectric ceramic pieces are opposite, an electrode plate is sandwiched in the middle, two ends of the piezoelectric crystal pile are respectively provided with an insulating gasket, the piezoelectric crystal pile is bonded through conductive adhesive and is respectively connected to a bending disc, a front radiation head or a tail mass block through a prestressed bolt sleeved with an insulating sleeve, the piezoelectric crystal pile is fixed along the orthogonal diameter direction through the prestressed bolt, the cascading units are connected in a staggered and serial mode, and two electrode connecting lines are led out in the polarization direction of the piezoelectric crystal pile pressing the piezoelectric ceramic pieces and are connected with an output cable.

2. The cascade piezoelectric ceramic underwater acoustic transducer of claim 1, wherein the curved disk is a disk-shaped curved beam, the curved disk is connected with the piezoelectric crystal stacks in two mutually orthogonal diameter directions, one side of the curved disk is connected with two groups of piezoelectric crystal stacks of one cascade unit, the other side of the curved disk is connected with two groups of piezoelectric crystal stacks of an adjacent cascade unit, and the cascade units are connected in series.

Technical Field

The invention relates to the technology of electroacoustic sensors, in particular to a cascade piezoelectric ceramic underwater acoustic transducer which is used for realizing the interconversion of electroacoustic energy and is suitable for the underwater detection and communication underwater acoustic field.

Background

The underwater acoustic transducer is an indispensable key device of underwater acoustic equipment, plays an extremely important role in underwater weapons, equipment and various civil detection, and the performance of the underwater acoustic transducer directly influences the function of the whole system. With the increasing demand of modern underwater acoustic applications, the features of low frequency, small size and light weight of underwater acoustic transducers have become an important trend in their development. The low-frequency transducers which are widely applied at present comprise various types of flextensional transducers, bending transducers, various types of Helmholtz resonators, giant magnetostrictive low-frequency underwater acoustic transducers and the like.

The limiting relationship between the size of an underwater acoustic transducer and its acoustic performance is discussed in detail in the published literature "Basic schemes used by depth and size constraints in low-frequency underservers" (Journal of the acoustic Society of America, United States, Volume 68, Issue 4,1980, 1031-. In The literature "The design of low frequency understeer acoustic detectors: present States and future turns" (IEEE journal of acoustic Engineering, United States, Volume 16, Issue 1,1991, 107) several commonly used low frequency hydroacoustic emitting transducer types are summarized, mainly including various flextensional transducers that utilize flexural vibration modes and Helmholtz resonators that utilize liquid cavity resonance modes. In the literature "Thin, light electronic sound projector for low frequency underwater applications" (Journal of the electronic sound of America, United States, Volume 116, Issue 3,2004,1536 and 1543), a lightweight cymbal type low frequency underwater acoustic transducer is described, with a transducer size of (381 × 280 × 64) mm and an underwater weight of 26N, which can effectively generate sound in the frequency range of 3-15 kHz.

In recent years, great progress has been made in low frequency miniature transducers in China. In the document "design of a small-sized low-frequency broadband sound source transducer" (acoustic technology, vol.32, No. 6, 2013, 285-286), a symmetric double-laminated curved disk transducer is proposed, which has a size of 200mm x 30mm, a mass of not more than 3kg, and can operate in the frequency range of 260Hz to 2450 Hz. Patent CN 107509149 a "a small-sized large-amplitude coil spring low-frequency transducer" describes a coil spring transducer that realizes the characteristics of low frequency, small size, and large displacement. Patent CN 102136268A, "a folding piezoelectric ceramic low-frequency underwater acoustic transducer" discloses a piezoelectric transducer with a folding structure, which realizes the characteristics of low frequency, light weight and small size. In patent CN 109935223 a, "a super small size low frequency transmitting transducer" describes a low frequency transmitting transducer formed by arranging a plurality of bar-shaped vibrating units, which has the characteristics of small size and high transmitting source level, and can realize low frequency resonance of 500Hz, transmitting source level greater than 185dB, and mass about 10 kg.

The research results of the existing small low-frequency transducer mostly adopt the bending vibration mode of the integral structure or components of the transducer, and the low-frequency transducer is light and small to a certain extent. However, from a practical application point of view, there is also a need for a lower-frequency transducer that is smaller in size and lighter in weight.

Disclosure of Invention

In order to avoid the defects of the prior art, the invention provides a cascade piezoelectric ceramic underwater acoustic transducer. The transducer reasonably couples the longitudinal vibration of a structural body and the bending vibration of a bending disk, fully utilizes the volume space, and realizes the low frequency and light and small characteristics of the underwater acoustic transducer through flexible cascade connection.

The technical scheme adopted by the invention for solving the technical problems is that the balance weight type cable comprises a front radiation head, a cascade unit, a balance weight shell and an output cable, and is characterized in that the balance weight shell comprises a waterproof cover, a tail mass block and a fastening bolt; the cascade unit comprises a bending disc, a piezoelectric crystal stack, a spring gasket and a prestressed bolt; the piezoelectric crystal stack comprises an insulating gasket, an electrode plate, a piezoelectric ceramic piece, an insulating sleeve and an electrode connecting wire; the front radiation head and the counterweight shell are respectively positioned at two ends of the transducer, the front radiation head is of a horn-shaped structure, the opening end of the front radiation head is outward favorable for outward radiation of sound energy, a circumferential groove is formed in the throat part of the front radiation head for mounting a sealing ring, the sealing ring is tightly matched with the waterproof cover to form a watertight structure, and the throat part of the front radiation head is connected with the cascade unit through a prestressed bolt;

The cascade unit is a plurality of cascade units, the cascade units are connected in series into a whole and positioned between the front radiation head and the counterweight shell, each cascade unit is formed by arranging two groups of piezoelectric crystal stacks side by side and is tightly connected with the bending disc through a prestressed bolt, each group of piezoelectric crystal stacks is formed by electrically connecting and mechanically connecting and bonding an even number of piezoelectric ceramic plates in series according to positive and reverse polarization directions, the waterproof cover is connected with the tail mass block through a fastening bolt, and the output cable penetrates through the counterweight shell and an electrode connecting wire of the piezoelectric crystal stacks to be connected to an external excitation source;

The piezoelectric crystal pile is formed by bonding piezoelectric ceramic pieces with holes in the middle, the polarization directions of the adjacent piezoelectric ceramic pieces are opposite, an electrode plate is sandwiched in the middle, two ends of the piezoelectric crystal pile are respectively provided with an insulating gasket, the piezoelectric crystal pile is bonded through conductive adhesive and is respectively connected to a bending disc, a front radiation head or a tail mass block through a prestressed bolt sleeved with an insulating sleeve, the piezoelectric crystal pile is fixed along the orthogonal diameter direction through the prestressed bolt, the cascading units are connected in a staggered and serial mode, and two electrode connecting lines are led out in the polarization direction of the piezoelectric crystal pile pressing the piezoelectric ceramic pieces and are connected with an output cable.

The bending disk is a disk-shaped bending beam, the bending disk is connected with the piezoelectric crystal stacks in two mutually orthogonal diameter directions, one side of the bending disk is connected with the two piezoelectric crystal stacks of one cascade unit, the other side of the bending disk is connected with the two piezoelectric crystal stacks of the adjacent cascade unit, and the cascade units are connected in series.

Advantageous effects

the cascade piezoelectric ceramic underwater acoustic transducer reasonably couples the longitudinal vibration of a structural body and the bending vibration of a bending disk, fully utilizes the volume space, and realizes the low frequency and light and small features of the underwater acoustic transducer through flexible cascade connection. The transducer has simple structure and stable performance, can be widely applied to the fields of underwater detection and underwater acoustic communication, is suitable for carrying various underwater carriers to carry out underwater operation, is suitable for the dense low-frequency array emission in various sonar equipment, and realizes special acoustic performance.

The cascade piezoelectric ceramic underwater acoustic transducer has the characteristics of remarkable low frequency, small size and light weight, can effectively work in the frequency band range of 200 Hz-50 kHz, and belongs to a strong power radiator. All the piezoelectric ceramic pieces of the transducer are electrically connected in parallel, positive electrodes are connected into a whole according to the polarization direction of the piezoelectric ceramic pieces, negative electrodes are connected into a whole, and the piezoelectric ceramic pieces are connected to an external excitation source through leads. The underwater acoustic transducer has simple structure, convenient manufacture and stable performance, is a light and small underwater sound source with excellent performance, and provides possibility for realizing a densely-distributed low-frequency array in various sonar equipment. The cascade piezoelectric ceramic underwater acoustic transducer is structurally designed, so that the size and the weight of the transducer are greatly reduced on the premise of keeping the low-frequency characteristic of the transducer, the electroacoustic performance of the transducer is optimized, and the special requirements in practical application are met.

Drawings

The cascade piezoelectric ceramic underwater acoustic transducer of the present invention is further described in detail with reference to the accompanying drawings and embodiments.

FIG. 1 is a schematic view of a cascade piezoelectric ceramic underwater acoustic transducer according to the present invention.

Fig. 2 is a schematic structural diagram of a cascade unit of the cascade piezoelectric ceramic underwater acoustic transducer of the invention.

FIG. 3 is a schematic diagram showing the connection relationship between the front radiation head and the piezoelectric crystal stack of the piezoelectric ceramic underwater acoustic transducer of the present invention.

FIG. 4 is a schematic view of a counterweight housing of the piezoelectric ceramic underwater acoustic transducer of the present invention.

In the drawings

1. Front radiation head 2, sealing ring 3, cascade unit 4, bending disk 5, insulating gasket 6, electrode plate 7, piezoelectric ceramic piece 8, water shield 9, tail mass block 10, output cable 11, counterweight shell 12, prestressed bolt 13, spring gasket 14, insulating sleeve 15, piezoelectric crystal pile 16, fastening bolt 17, electrode connecting wire

Detailed Description

The embodiment is a cascade piezoelectric ceramic underwater acoustic transducer.

Referring to fig. 1 to 4, the cascaded piezoelectric ceramic underwater acoustic transducer of the present embodiment is composed of a front radiation head 1, a cascaded unit 3, a counterweight housing 11, and an output cable 10; the counterweight housing 11 comprises a waterproof cover 8, a tail mass block 9 and a fastening bolt 16, the cascade unit 3 comprises a bending disc 4, a piezoelectric crystal stack 15, a spring gasket 13 and a prestressed bolt 12, and the piezoelectric crystal stack 15 comprises an insulating gasket 5, an electrode plate 6, a piezoelectric ceramic plate 7, an insulating sleeve 14 and an electrode connecting wire 17. The front radiation head 1 and the counterweight shell 11 are respectively arranged at two ends of the transducer, and the front radiation head 1 is of a horn-shaped structure, can be of a truncated cone shape, and can also be of an exponential bus structure. The horn end of the front radiation head 1 faces outwards, and the larger area of the front radiation head is beneficial to the outward radiation of the acoustic energy. The throat part of the front radiation head 1 is provided with a sealing ring groove for installing a sealing ring 2, the sealing ring 2 is tightly matched with the waterproof cover 8 to form a watertight structure, and the throat part of the front radiation head 1 is connected with the cascade unit 3 through a prestressed bolt 12. The front radiation head 1 is made of hard aluminum light metal. The weight housing 11 is a heavy metal. Therefore, a larger front-back vibration speed ratio can be obtained, and the forward radiation of sound energy is facilitated. The bolt is matched with the epoxy glue to be tightly bonded, so that the watertight performance of the transducer is ensured, and the functional requirement of the large-mass counterweight at the tail part of the transducer is met.

The cascade unit 3 is a plurality of, cascade unit 3 concatenates an organic whole and is located the middle of front radiation head 1 and counter weight casing 11, every cascade unit is placed side by two sets of piezocrystal piles 15, and through prestressing force bolt and crooked disc close connection, every group piezocrystal pile is by even number piezoceramics piece according to positive, the electricity is parallelly connected, mechanical series connection bonds forms, buckler 8 and tail quality piece 9 are connected through fastening bolt 16, piezocrystal pile 15 is fixed along orthogonal diametric direction through prestressing force bolt 12, the crisscross concatenation of each cascade unit, piezocrystal pile 15 presses the polarization direction of piezoceramics piece 7 to draw forth two electrode connecting wires 17 and is connected with output cable 10. The output cable 10 is connected to the external excitation source through the counterweight housing 11 and the electrode connection 17 of the piezoelectric crystal stack 15.

The cascade units of the embodiment range from 3 to 15 and are connected in series end to end through the prestressed bolts 12. The piezoelectric crystal stacks 15 are fixed along the orthogonal diameter direction through the prestressed bolts 12, so that the staggered serial connection of all the cascade units is ensured.

The number of the transducer cascade units is not fixed, and the number of the transducer cascade units can be flexibly adjusted according to the realized transducer performance. All the cascade units are connected end to end into a whole, and the two ends of the cascade unit part connected in series are respectively connected with the front radiation head and the counterweight shell. The cascaded units are generally identical in structure, each of which is formed by a piezoelectric crystal stack and a curved disk. The piezoelectric crystal stacks are divided into two groups, are arranged in parallel along a certain diameter direction of the bending disk and are tightly connected to the bending disk through the prestressed bolts, but the outermost edge of the piezoelectric crystal stack is required to be flush with the outermost edge of the bending disk. The curved disk 4 is a disk-shaped curved beam, and is connected to the piezoelectric crystal stack in two mutually orthogonal diametric directions. The two sides of the bending disk are respectively connected with the piezoelectric crystal stacks of the adjacent cascading units, but it needs to be ensured that when one side of the bending disk is connected with the two piezoelectric crystal stacks of the cascading units along a certain diameter direction, the other side of the bending disk needs to be connected with the two piezoelectric crystal stacks of the adjacent cascading units in the orthogonal diameter direction, so that the end-to-end connection of each cascading unit is realized. This has the advantage that the bending vibration mode of the bending disk can be fully utilized to obtain maximum longitudinal vibration displacement of the transducer radiating head, thereby facilitating the outward radiation of acoustic energy. The thickness of the bent disc is thin, the hole can be optimized, and the bent disc is designed according to performance indexes to be realized by the transducer; to take full advantage of the bending mode of the bending disk 4, the thickness of the bending disk 4 is typically in the range of 5 to 10 mm.

Detailed assembly process

(1) And sequentially adhering the insulating gasket 5, the electrode plate 6 and the piezoelectric ceramic plate 7 by using conductive adhesive to complete the adhesion of the piezoelectric crystal stack 15.

(2) Connecting the two groups of piezoelectric crystal stacks 15 finished in the step (1) with the bending disk 4 through the prestressed bolts 12 according to the structure to finish the cascade unit 3.

(3) Fastening the cascade unit 3 completed in step (2) to the front radiation head 1 using the pre-stressed bolts 12. The connection of the first layer of cascaded units 3 to the front radiation head 1 is achieved. Note that appropriate prestress should be applied when tightening the prestress bolt 12.

(4) completing the piezoelectric crystal stack 15 in the same step (1), completing the cascade units 3 in the synchronous step (2), and sequentially fastening the completed cascade units 3 on the cascade unit 3 on the upper layer to realize the serial connection structure of a plurality of cascade units.

(5) The last layer of cascade units 3 is fastened to the tail mass 9 by means of prestressed bolts 12.

(6) The welding of the electrode connecting lines 17 of the piezoelectric crystal stacks 15 is completed, and all the piezoelectric crystal stacks are electrically connected in parallel pressing the polarization directions of the piezoelectric ceramic plates 7.

(7) and (3) enabling the output cable 10 to penetrate through corresponding holes of the waterproof cover 8 and the tail mass block 9 and be connected to the electrode connecting wire 17 completed in the step (6).

(8) Fastening the waterproof cover 8 to the tail mass block 9 by fastening bolts 16 and completing the watertight fit of the waterproof cover 8 with the front radiation head 1 and the seal ring 2 of the tail mass block 9.

The cascaded piezoelectric ceramic underwater acoustic transducer of the embodiment reasonably couples the longitudinal vibration of the structural body and the bending vibration of the bending disk, and can realize the low-frequency characteristic of the transducer in a smaller volume space, particularly under the condition of smaller cross section size. The whole transducer is of a columnar structure, the size of the cross section of the transducer is small, the structure is particularly suitable for assembling various underwater carriers, the transducer is particularly suitable for densely-distributed array emission in various sonar equipment, and excellent acoustic performance can be realized in the fields of underwater detection and underwater acoustic communication.