A combined polarization ultra-low frequency flexural disk transducer and its preparation method

Abstract

The present invention relates to a combined polarized ultra-low frequency curved disk transducer and a preparation method thereof. The two transducer components are opposed to each other with the radiation surface facing outward, and an air cavity is provided between the two transducer components. A connecting cable is provided for the two transducer components, and a combined polarization component is provided for any of the transducer components. The present invention combines tangential polarization with thickness polarization. On the basis of conventional thickness polarization, tangential polarization is added to compensate for the vibration displacement at the outer position to obtain a better vibration mode and a larger vibration displacement. By changing the distribution of the piezoelectric elements, the equivalent distribution space of the active driving material is increased. While reducing the resonant frequency of the curved disk transducer, it has a higher transmission voltage response and improves the transmission capability of the transducer. A new implementation method of tangential polarization is proposed to solve the short circuit problem between the element and the metal plate, ensure the adaptability of the vibration mode between the materials, and make the entire transducer have a better vibration mode.

Description

Technical Field

[0001] The present invention relates to the technical field of accessories specially suitable for underwater use, such as hydrophones, and in particular to a combined polarization ultra-low frequency curved disk transducer and a preparation method thereof. Background Art

[0002] Underwater acoustic transducers are sensors that convert sound into other forms of energy or information within a water medium. They are the most advanced devices in sonar systems and serve as a window through which the sonar system interacts and exchanges information with the water medium. The first technical challenge facing transducer development is geometric size. Generally, the operating frequency of a resonant transducer is inversely proportional to its size; that is, the lower the frequency, the larger the size. However, bending vibration can effectively reduce the size of low-frequency transducers.

[0003] As underwater acoustic detection technology develops towards deep water, ultra-low frequency and high power, when the operating frequency drops to hundreds of hertz or even tens of hertz, the effective diameter of the curved disk transducer increases sharply. However, due to the limitations of the piezoelectric ceramic component molding process, the preparation of large-sized piezoelectric ceramics has encountered a bottleneck and cannot drive large-sized metal disks. Therefore, under the existing piezoelectric ceramic component supply conditions, it is necessary to explore multi-element distributed driving methods to achieve a significant reduction in the resonant frequency of the curved disk transducer to meet the development needs of low-frequency underwater acoustic long-range detection and communication technology.

[0004] In the existing technology, the problem of difficulty in producing large-area piezoelectric ceramic components is often solved by assembling multiple small-sized piezoelectric ceramic discs to replace large-sized discs, such as the technical solutions involved in the Chinese patent "An Ultra-Low Frequency Bending Disc Transducer" (publication number CN109195066A) and the Chinese patent "Inlaid Large-Area Low-Frequency Bending Transducer" (publication number CN202662280U). Although these technologies solve the structural problems of the transducer, they do not improve the transducer performance. Conventional distributed excitation bending disk transducers still use thickness-polarized piezoelectric ceramic discs evenly embedded in a metal plate. Although low-frequency transmission is achieved, it is limited by the single distribution method and the small area of the equivalent piezoelectric material area, resulting in a low transmission voltage response of the transducer and a narrow -3dB response bandwidth. The transmission voltage response level at the resonance point is low and the maximum sound source level is small.

[0005] Furthermore, regarding the implementation of tangential polarization, for example, the Chinese patent "Inlaid Curved Disk Underwater Acoustic Transducer" (publication number CN107580274A) discloses that fan-shaped ceramic elements are bonded to the surface of a metal plate, which largely does not optimize the vibration mode of the curved disk transducer. Summary of the Invention

[0006] The present invention solves the problems existing in the prior art and provides an optimized combined polarization ultra-low frequency curved disk transducer and a preparation method thereof. Aiming at the development needs of ultra-low frequency long-range detection of mobile deployment platforms, the present invention targets the bottleneck that the existing manufacturing process cannot prepare large-sized piezoelectric elements suitable for curved disk transducers. By changing the distribution and polarization mode of the piezoelectric ceramic elements of the curved disk transducer, the vibration mode of the curved disk transducer is changed, thereby achieving a further lowering of the resonant frequency, improving the emission capability of the transducer, and making it adaptable to the development needs of future mobile detection systems.

[0007] The technical solution adopted by the present invention is a combined polarized ultra-low frequency curved disk transducer, comprising two oppositely arranged transducer components, wherein the radiation surface of any of the transducer components faces outward, and an air cavity is provided between the two transducer components; a connecting cable is provided to cooperate with the two transducer components;

[0008] A combined polarization component is provided in conjunction with any of the transducer components.

[0009] Preferably, any of the transducer components includes a bracket ring, a bottom plate is embedded in the inner wall of the bracket ring, and a combined polarization component is distributed on the bottom plate; a lead hole is provided in conjunction with the bottom plate, and a wire outlet hole is provided in conjunction with the bracket ring.

[0010] Preferably, the combined polarization component includes a thickness polarizer arranged in the center of the base plate and several concentric tangential polarizers arranged outside the thickness polarizer, with the side of the thickness polarizer in contact with the base plate as the negative pole, and isolation rings are provided between adjacent tangential polarizers and between the tangential polarizers and the thickness polarizers.

[0011] Preferably, any tangential polarization member includes a plurality of fan-shaped elements connected end to end, the polarization directions of two adjacent fan-shaped elements are opposite, and an electrode sheet is provided between the two adjacent fan-shaped elements.

[0012] Preferably, grooves are provided on the bottom plate corresponding to the thickness polarization element and the tangential polarization element.

[0013] Preferably, an insulating layer is provided in the groove of the bottom plate corresponding to any of the tangential polarization elements.

[0014] Preferably, the bottom plate is arranged in the middle of the inner wall of the bracket ring.

[0015] Preferably, the combined polarization component of the bottom plate is covered with a radiation surface, and the radiation surface is a colloid; the top surface of the radiation surface is flush with the edge of the corresponding bracket ring.

[0016] Preferably, the angle between the connecting lines between the lead-in hole, the outlet hole and the axis of the transducer component is α, and 0≤α≤30°.

[0017] A method for preparing a combined polarization ultra-low frequency curved disk transducer, the method comprising the following steps:

[0018] Step 1: Assemble the base plate and bracket ring to achieve the boundary condition of simple support;

[0019] Step 2: Glue the combined polarization components to the corresponding position of the base plate;

[0020] Step 3: Connect the wires of the same polarity in parallel, lead them into the cavity inside the component structure through the lead hole on the bottom plate, and then lead them out through the lead hole of the bracket ring;

[0021] Step 4: Treat the perfusion area outside the combined polarization component on the bottom plate and inject liquid colloid, which forms a watertight layer after solidification, which serves as the radiation surface;

[0022] Step 5: Follow steps 1 to 4 to complete the assembly of another transducer component and proceed to the next step;

[0023] Step 6: Fasten the two transducer components through the screw holes on the bracket ring, use a two-to-one connecting cable to process the lead wires of the two components, and assemble to form a complete transducer.

[0024] The present invention relates to an ultra-low frequency curved disk transducer with optimized combined polarization and a preparation method thereof. Two opposing transducer components are provided, with the radiation surface of any transducer component facing outward, and an air cavity is provided between the two transducer components. A connecting cable is provided in conjunction with the two transducer components, and most importantly, a combined polarization component is provided in conjunction with any transducer component to achieve thickness polarization and tangential polarization.

[0025] The beneficial effects of the present invention are:

[0026] (1) Starting from changing the distribution and polarization mode of the piezoelectric ceramic active material that drives the metal plate, a combination of tangential polarization and thickness polarization is adopted. Taking advantage of the larger d33 coefficient of the piezoelectric material, tangential polarization is added on the basis of conventional thickness polarization to compensate for the vibration displacement of the outer position, so as to obtain a better vibration mode and a larger vibration displacement;

[0027] (2) By changing the distribution of piezoelectric elements, the equivalent distribution space of active driving materials is increased;

[0028] (3) Based on the above two points, while reducing the resonant frequency of the curved disk transducer, it has a higher transmission voltage response and improves the transmission capability of the transducer;

[0029] (4) A new method for implementing tangential polarization is proposed, which not only solves the short circuit problem between the element and the metal plate, but also ensures the adaptability of the vibration modes between the materials, so that the entire transducer has a better vibration mode. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 Schematic diagram of the component structure of the transducer of the present invention, (a) is a schematic diagram of the component structure before perfusion, (b) is a schematic diagram of the component structure with a watertight layer;

[0031] Figure 2 Schematic diagram of the support ring structure of the transducer of the present invention;

[0032] Figure 3 1 is a schematic diagram of the base plate structure of the transducer of the present invention;

[0033] Figure 4 Schematic diagram of the distribution of piezoelectric elements of the transducer of the present invention;

[0034] Figure 5 Schematic diagram of the complete ultra-low frequency curved disk transducer structure of the present invention, (a) is a schematic diagram of the transducer before perfusion, (b) is a schematic diagram of the complete transducer structure with a watertight layer; (c) is a cross-sectional diagram of the complete transducer;

[0035] Figure 6 This is a schematic diagram of the bonding local structure of the tangentially polarized sector-shaped element of the present invention;

[0036] Figure 7 This is the acoustic performance comparison result of the transducer of the present invention and the thickness-polarized wafer distributed transducer. DETAILED DESCRIPTION

[0037] The present invention is further described in detail below with reference to the embodiments, but the protection scope of the present invention is not limited thereto.

[0038] The present invention relates to a combined polarized ultra-low frequency curved disk transducer, comprising two transducer components 1 arranged opposite to each other, wherein a radiation surface 2 of any transducer component 1 faces outward, an air cavity 3 is provided between the two transducer components 1, and a connecting cable 4 is provided for the two transducer components 1.

[0039] A combined polarization component is provided in conjunction with any of the transducer components 1 .

[0040] In the present invention, the disc transducer adopts an upper and lower symmetrical structure and is composed of two completely identical transducer components 1 that are relatively combined. Each transducer component 1 includes a wire outlet hole 5, a bracket ring 6, a base plate 7, a piezoelectric ceramic element, and a radiation surface 2 (watertight layer); the two transducer components 1 can be fastened together by screws to form a complete ultra-low frequency bending disc transducer.

[0041] In the present invention, a combined polarization component is provided in the transducer component 1, which has the capabilities of thickness polarization and tangential polarization, and performs displacement compensation on the vibration displacement of the outer position to obtain a better vibration mode and a larger vibration displacement.

[0042] Any of the transducer components 1 includes a bracket ring 6, a bottom plate 7 is embedded in the inner wall of the bracket ring 6, and a combined polarization component is distributed on the bottom plate 7; a lead hole 8 is provided in conjunction with the bottom plate 7, and a wire outlet hole 5 is provided in conjunction with the bracket ring 6.

[0043] In the present invention, the support ring 6 and the bottom plate 7 are assembled and engaged with each other to achieve the physical condition of boundary simple support.

[0044] In the present invention, generally speaking, the support ring 6 and the bottom plate 7 are made of metal materials, preferably stainless steel, and the bottom plate 7 can be made of 45# steel.

[0045] In the present invention, the lead holes 8 on the bottom plate 7 are used for the leads of the piezoelectric element, and the outlet holes 5 are used for outlet wires.

[0046] The combined polarization assembly includes a thickness polarizer 9 arranged at the center of the base plate 7 and several concentric tangential polarizers arranged outside the thickness polarizer 9. The side of the thickness polarizer 9 in contact with the base plate 7 is the negative pole, and isolation rings 10 are provided between adjacent tangential polarizers and between the tangential polarizers and the thickness polarizer 9.

[0047] Any tangential polarization element includes a plurality of sector-shaped elements 11 connected end to end. The polarization directions of two adjacent sector-shaped elements 11 are opposite. An electrode sheet 12 is provided between the two adjacent sector-shaped elements 11 .

[0048] Grooves 13 are provided on the bottom plate 7 corresponding to the thickness polarizer 9 and the tangential polarizer.

[0049] An insulating layer 14 is provided in the groove 13 of the bottom plate 7 corresponding to any of the tangential polarization elements.

[0050] In the present invention, the thickness polarizer 9 and the sector-shaped element 11 of the tangential polarizer are actually piezoelectric ceramic elements, and are embedded in the groove 13 on the bottom plate 7 by bonding.

[0051] In the present invention, the thickness polarizer 9 is arranged at the center of the base plate 7 and is polarized in the thickness direction. Generally, for convenience, it can be set as a piezoelectric disc. Of course, it can also be set as a ring or fan-shaped piece according to needs; several concentric tangential polarizers are outside the thickness polarizer 9 and are in the form of a ring. Each tangential polarizer is spliced by tangentially polarized fan-shaped elements 11, and the polarization directions of adjacent fan-shaped elements 11 are opposite, and they are connected in parallel in the circuit through electrode sheets 12.

[0052] In the present invention, before the fan-shaped element 11 is spliced, an insulating layer 14 must be laid in the groove 13 of the base plate 7 to prevent a short circuit between the fan-shaped element 11 and the electrode sheet 12. The insulating layer 14 is preferably made of the same material as the ceramic element, such as unpolarized piezoelectric ceramic.

[0053] The bottom plate 7 is arranged at the middle of the inner wall of the bracket ring 6 .

[0054] The combined polarization component of the bottom plate 7 is covered with a radiation surface 2 , which is a colloid; the top surface of the radiation surface 2 is flush with the edge of the corresponding bracket ring 6 .

[0055] The angle between the connecting lines between the lead-in hole 8 and the outlet hole 5 and the axis of the transducer component 1 is α, 0≤α≤30°.

[0056] In the present invention, the lead hole 8 on the bottom plate 7 and the outlet hole 5 of the bracket ring 6 are approximately at the same azimuth angle, which is convenient for subsequent lead-in and outlet. Therefore, in practical applications, 0≤α≤10° is more preferred.

[0057] The present invention also relates to a method for preparing a combined polarization ultra-low frequency curved disk transducer, the method comprising the following steps:

[0058] Step 1: Assemble the base plate 7 and the bracket ring 6 to achieve the boundary condition of simple support; during the assembly process, it is necessary to ensure that the lead hole 8 on the base plate 7 and the outlet hole 5 of the bracket ring 6 are approximately at the same azimuth angle, generally within the difference range of ±10°, to facilitate subsequent lead-in and outlet.

[0059] Step 2: Glue the combined polarization components at the corresponding position of the base plate 7; first glue the thickness polarization member 9 with thickness polarization to the center of the base plate 7, with the bonding surface as the negative pole, and the outer circular area is spliced with tangentially polarized fan-shaped elements 11. The polarization directions of the two adjacent fan-shaped elements 11 are opposite, and the two are connected in parallel in the circuit through the electrode sheet 12; at the same time, before splicing the fan-shaped elements 11, an insulating layer 14 must be laid in the groove 13 of the base plate 7 to prevent short circuits between the fan-shaped elements 11 and the electrode sheets 12. The insulating layer 14 is made of the same material as the ceramic element, preferably unpolarized piezoelectric ceramics.

[0060] Step 3: Connect the wires of the same polarity in parallel, lead them into the cavity inside the component structure through the lead hole 8 on the bottom plate 7, and then lead them out through the lead hole 5 of the bracket ring 6;

[0061] Step 4: Treat the pouring area outside the combined polarization component on the bottom plate 7 and inject liquid colloid, which forms a watertight layer after solidification, which is the radiation surface 2; specifically, protect the component area in the pouring glue tank, sandblast the pouring area, clean it, apply primer, preheat and inject liquid colloid to ensure that the glue tank is filled with colloid, and the pouring surface is flat and free of bubbles. After solidification, a watertight layer is formed, which is the radiation surface 2.

[0062] Step 5: After completing the assembly of another transducer component 1 according to steps 1 to 4, proceed to the next step;

[0063] Step 6: Fasten the two transducer components 1 through the screw holes 15 on the bracket ring 6, use a two-to-one connecting cable 4 to connect the lead wires of the two components 1, perform vulcanization and other treatments, and assemble to form a complete transducer.

[0064] The present invention realizes high-power ultra-low frequency transmission while maintaining a certain volume size. Figure 7 As shown, the acoustic performance comparison results of the combined polarization distributed bending disk transducer and the thickness polarization circular disc distributed transducer are obtained under the premise of the same size of the base plate 7 and the bracket ring 6 and the same equivalent area of the piezoelectric ceramics.

Claims

1. A combined polarization ultra-low frequency curved disk transducer, characterized in that: It comprises two transducer components arranged opposite to each other, the radiation surface of any of the transducer components faces outward, an air cavity is provided between the two transducer components; and a connecting cable is provided to cooperate with the two transducer components; Any of the above-mentioned transducer components includes a bracket ring, a base plate is embedded in the inner wall of the bracket ring, and a combined polarization component is distributed on the base plate; the combined polarization component includes a thickness polarization piece arranged in the center of the base plate and a plurality of concentric tangential polarization pieces arranged outside the thickness polarization piece, with the side of the thickness polarization piece in contact with the base plate being the negative pole, and isolation rings are provided between adjacent tangential polarization pieces and between the tangential polarization pieces and the thickness polarization pieces.

2. The combined polarization ultra-low frequency curved disk transducer according to claim 1, characterized in that: A lead-in hole is provided in conjunction with the bottom plate, and a wire outlet hole is provided in conjunction with the bracket ring.

3. The combined polarization ultra-low frequency curved disk transducer according to claim 1, characterized in that: Any tangential polarization piece includes a plurality of fan-shaped elements connected end to end, the polarization directions of two adjacent fan-shaped elements are opposite, and an electrode sheet is provided between the two adjacent fan-shaped elements.

4. The combined polarization ultra-low frequency curved disk transducer according to claim 1, characterized in that: Grooves are provided on the bottom plate corresponding to the thickness polarization piece and the tangential polarization piece.

5. The combined polarization ultra-low frequency curved disk transducer according to claim 4, characterized in that: An insulating layer is provided in the groove of the bottom plate corresponding to any of the tangential polarization elements.

6. The combined polarization ultra-low frequency curved disk transducer according to claim 1, characterized in that: The bottom plate is arranged at the middle part of the inner wall of the bracket ring.

7. The combined polarization ultra-low frequency curved disk transducer according to claim 6, characterized in that: The combined polarization component of the bottom plate is covered with a radiation surface, which is a colloid; the top surface of the radiation surface is flush with the edge of the corresponding bracket ring.

8. The combined polarization ultra-low frequency curved disk transducer according to claim 2, characterized in that: The angle between the connecting lines between the lead-in hole, the outlet hole and the axis of the transducer component is α, 0≤α≤30°.

9. A method for preparing a combined polarization ultra-low frequency curved disk transducer according to any one of claims 1 to 8, characterized in that: The method comprises the following steps: Step 1: Assemble the base plate and bracket ring to achieve the boundary condition of simple support; Step 2: Glue the combined polarization components to the corresponding position of the base plate; Step 3: Connect the wires of the same polarity in parallel, lead them into the cavity inside the component structure through the lead hole on the bottom plate, and then lead them out through the lead hole of the bracket ring; Step 4: Treat the perfusion area outside the combined polarization component on the bottom plate and inject liquid colloid, which forms a watertight layer after solidification, which serves as the radiation surface; Step 5: Follow steps 1 to 4 to complete the assembly of another transducer component and proceed to the next step; Step 6: Fasten the two transducer components through the screw holes on the bracket ring, use a two-to-one connecting cable to process the lead wires of the two components, and assemble to form a complete transducer.

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