Receiving and transmitting integrated tenon-and-mortise type underwater acoustic transducer

Abstract

The invention discloses a receiving and transmitting integrated tenon-and-mortise type underwater acoustic transducer, and belongs to the field of piezoelectric materials and sensors thereof. The device comprises a tenon-and-mortise-shaped piezoelectric module, a backing layer, a multi-core cable, a rear end cover and a watertight layer. The tenon-and-mortise-shaped piezoelectric module is mainly composed of a tenon-shaped unit, a mortise-shaped unit, an electrode unit and a rubber unit. The tenon-shaped units and the mortise-shaped units are connected through the rubber units. After the rigid tenon modules and the rigid mortise modules are stacked in the longitudinal direction through the rubber units, multimode bandwidth expansion is achieved. The backing layer is fixed at the bottom of the tenon-and-mortise-shaped piezoelectric module and plays a role in supporting the piezoelectric module and absorbing clutters; the multi-core cable is fixed at the bottom of the backing layer, one end is connected with all the leads, and the other end is led out from the inner side of the slotted hole of the rear end cover. The tenon-and-mortise-shaped piezoelectric module, the back lining layer and the top end face of the rear end cover are wrapped by the watertight layer. The tenon-and-mortise-shaped piezoelectric modules all comprise air gap units, and the air gap units do not contain any polymer material, so that the coupling between piezoelectric columns is reduced to the minimum, and the sensitive receiving performance of the transducer can be improved.

Description

Technical Field

[0001] The invention relates to a mortise and tenon type underwater acoustic transducer with integrated transmitting and receiving function, belonging to the field of piezoelectric materials and sensors thereof. Background Art

[0002] A hydroacoustic transducer is a device that can convert sound wave signals into electrical signals and vice versa. It is widely used in underwater detection, communication, measurement and monitoring. Its working principle is to convert electrical signals into sound waves through vibration elements, and convert the sound waves back into electrical signals. Hydroacoustic transducers play an important role in marine science, military detection, environmental monitoring, etc. With the advancement of science and technology and the continuous increase in application needs, higher requirements are placed on their performance.

[0003] In the design and manufacture of underwater acoustic transducers, 1-3 type piezoelectric composite materials have attracted much attention due to their excellent electroacoustic properties. This composite material is a combination of piezoelectric ceramics and polymers, and has the following advantages: First, 1-3 type piezoelectric composite materials have a high electromechanical coupling coefficient, which can effectively improve the conversion efficiency of the transducer's acoustic energy; secondly, the material has high stability, can maintain good performance under different environmental conditions, and adapt to the complex underwater use environment; in addition, the low acoustic impedance characteristics of 1-3 type composite materials enable it to effectively reduce sound wave reflection in water and improve the effectiveness of signal transmission. Therefore, these advantages make 1-3 type piezoelectric composite materials often used in the development of high-performance underwater acoustic transducers.

[0004] However, the current Type 1-3 hydroacoustic transducers still have some shortcomings in practical applications, especially in terms of transmission bandwidth and the integration of transducer transmission and reception. Traditional hydroacoustic transducers are mostly single-function, that is, they can only be used for transmission or reception, which leads to low efficiency and limited performance of the system when performing complex signal processing. The existing transducer transmission bandwidth is small, which limits its application capabilities within a wide frequency range, which is particularly prominent in certain scenarios that require high-precision positioning and detection. Therefore, it is urgent to develop a new type of hydroacoustic transducer that integrates the transmission and reception functions to improve the overall performance and application flexibility. Through innovative materials and design concepts, the transmission and reception functions can be effectively integrated to achieve higher system integration, improve transmission efficiency and signal quality, and promote the widespread application of hydroacoustic transducers in various applications.

[0005] In short, with the advancement of technology, the design and manufacture of underwater acoustic transducers face new opportunities and challenges, especially in terms of material selection and functional integration. Future research should focus on improving the transmission bandwidth and integration of type 1-3 underwater acoustic transducers to meet the growing market demand and application scenarios. Summary of the invention

[0006] In order to solve the problems of low transmission bandwidth and low integration of transmission and reception of existing 1-3 type underwater acoustic transducers, the present invention provides a mortise and tenon type underwater acoustic transducer with integrated transmission and reception, which adopts mortise and tenon piezoelectric modules as sensitive units, and can have both broadband transmission and high-sensitivity reception performance. The mortise and tenon piezoelectric module is composed of a mortise unit and a mortise unit. The two units have similar thickness and are stacked and compounded along the thickness direction, and have coupled dual-resonance peak electrical properties, thereby achieving the purpose of improving the transmission bandwidth. The mortise and tenon piezoelectric modules all contain air gap units. Since the air gap units do not contain any polymer materials, the coupling between piezoelectric columns can be reduced to a minimum, which can enable the transducer to have high-sensitivity reception performance.

[0007] The present invention is achieved through the following technical solutions:

[0008] The present invention discloses a mortise and tenon type underwater acoustic transducer integrating transmission and reception, comprising a mortise and tenon type piezoelectric module, a backing layer, a multi-core cable, a rear end cover and a watertight layer.

[0009] The mortise and tenon piezoelectric module is mainly composed of a mortise unit, a tenon unit, an electrode unit and a rubber unit.

[0010] The height of the middle part matrix of the tenon unit is higher than that of the outer matrix, and the protruding part is called a rigid tenon module; the remaining part is called an air gap unit; a rigid polymer is filled between the rigid tenon module arrays; the end faces of the tenon unit are covered with electrode units; the rigid tenon module is covered with a first electrode plate; the air gap unit is covered with a second electrode plate; the above electrode units are respectively led out with leads.

[0011] The height of the middle part of the matrix of the mortise-shaped unit is lower than that of the outer matrix, and the concave part is called a rigid mortise module; the remaining part is called an air gap unit; a rigid polymer is filled between the rigid mortise module arrays; the end face of the mortise-shaped unit is covered with an electrode unit; the rigid mortise module is covered with a first electrode plate; the air gap unit is covered with a second electrode plate; the above electrode units are respectively led out with leads.

[0012] The tenon unit and the mortise unit are connected through the rubber unit; after the rigid tenon module and the rigid mortise module are stacked along the longitudinal direction through the rubber unit, multi-mode bandwidth expansion is achieved.

[0013] The backing layer is fixed to the bottom of the mortise and tenon-shaped piezoelectric module to support the piezoelectric module and absorb clutter; the multi-core cable is fixed to the bottom of the backing layer, one end of which is connected to all the above-mentioned leads, and the other end is led out from the inner side of the slot hole of the rear end cover.

[0014] The watertight layer wraps the mortise and tenon-shaped piezoelectric module, the backing layer and the top end surface of the rear end cover.

[0015] As a preferred embodiment, the rigid tenon module and the rigid mortise module are used as the transmitting unit of the transducer to realize the high mechanical strength broadband transmission of the transducer; the air gap unit of the tenon unit and the mortise unit is used as the receiving unit of the transducer for the high sensitivity reception of the transducer to meet the transceiver transceiver integrated function;

[0016] Preferably, the tenon-shaped unit and the mortise-shaped unit are made of PZT ceramic or PMN-PT single crystal to ensure high-intensity emission and high-sensitivity receiving performance; and the small columns in the array have exactly the same structural parameters.

[0017] Preferably, the rigid polymer material is epoxy resin or PMMA material, which is used to separate the small columns between the piezoelectric arrays and improve the stability and compression resistance of the piezoelectric arrays.

[0018] Preferably, the aspect ratio of the piezoelectric columns in the rigid tenon module and the rigid mortise module is not less than 4:1; the ratio of the width of the piezoelectric column to the array gap width is between 0.24 and 0.35, so as to ensure that the volume fraction of the piezoelectric phase is controlled within the high electromechanical conversion capability range of the material.

[0019] Preferably, the tenon-shaped units and mortise-shaped units are stacked in the thickness direction, wherein the protruding portion of the rigid tenon module should completely fit with the recessed portion of the rigid tenon structure.

[0020] Preferably, the rubber unit is made of a decoupling material rubber with a low Young's modulus; the thickness of the connecting unit does not exceed 1 mm, and the outer dimensions are adapted to the tenon unit and the mortise unit.

[0021] Preferably, the electrode unit comprises a first electrode plate and a second electrode plate; the electrode unit is made of metal material with a thickness not exceeding 0.5 mm.

[0022] Preferably, the backing layer is made of a foam material with high hardness and more pores. The high hardness means that the hardness is higher than a preset hardness threshold, and the more pores means that the number of pores is higher than a preset threshold.

[0023] Preferably, the watertight layer is made of a polyurethane material with strong matching and good sound permeability; the thickness of the watertight layer is controlled within 1 / 4 to 3 / 4 wavelength.

[0024] Preferably, the multi-core cable is used to connect the electrode unit leads.

[0025] Preferably, the rear end cover is made of metal material, and its outer dimensions are matched with those of the backing layer.

[0026] Beneficial effects:

[0027] 1. The present invention discloses a transceiver-transmitter-integrated mortise and tenon type underwater acoustic transducer, which uses a mortise and tenon structure piezoelectric module as a vibration element to achieve dual resonance coupling frequency band expansion, which can effectively improve the frequency bandwidth of traditional transducers. In addition, the mortise and tenon piezoelectric module effectively separates the transmitting unit and the receiving unit, which ensures both the wide-band transmission performance of the transducer and the high-sensitivity receiving performance of the transducer.

[0028] 2. The present invention discloses a mortise and tenon type underwater acoustic transducer with an integrated transmitter and receiver, which uses an integrated mortise and tenon structure to simultaneously realize the transmitting and receiving functions of the transducer, and has the advantages of light weight, small size and high integration. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The figure is a schematic diagram of the structure of a mortise and tenon type underwater acoustic transducer with integrated transmitter and receiver.

[0030] Figure 2 It is a schematic diagram of the explosion of a mortise and tenon type underwater acoustic transducer with integrated transmitter and receiver.

[0031] Figure 3 The present invention is a schematic diagram of the structure of a tenon unit of a mortise and tenon type underwater acoustic transducer with integrated transmitter and receiver.

[0032] Figure 4 The present invention is a schematic diagram of the structure of a mortise and tenon unit of a transceiver-transmitter-integrated mortise and tenon type underwater acoustic transducer.

[0033] Figure 5 It is a top view of a rigid tenon module / rigid mortise module of a mortise and tenon type underwater acoustic transducer with integrated transmitter and receiver.

[0034] Figure 6 A finite element simulation model was built for a mortise and tenon type underwater acoustic transducer with integrated transmitter and receiver.

[0035] Figure 7 This is the simulation result of the electrical admittance of a mortise and tenon type underwater acoustic transducer with integrated transmitter and receiver.

[0036] Figure 8 The simulation results show the transmission voltage response of the transmitting unit of a mortise and tenon type underwater acoustic transducer with integrated transmitter and receiver.

[0037] Fig. 9 The simulation results show the receiving voltage sensitivity of the receiving unit of a transceiver-transmitter-mortise and tenon-joint underwater acoustic transducer.

[0038] In the figure, 1 is a watertight layer, 2 is a tenon unit, 3 is a first electrode plate, 4 is an electrode lead, 5 is a second electrode plate, 6 is a second rubber unit, 7 is a first rubber unit, 8 is a tenon unit, 9 is a backing layer, 10 is a rear end cover, 11 is a multi-core cable, 12 is a piezoelectric column, 13 is a rigid polymer, 14 is an air gap, and 15 is a piezoelectric substrate. DETAILED DESCRIPTION

[0039] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments and drawings.

[0040] Figure 1 This is a three-dimensional structural diagram of a transceiver-transmitter-mortise-and-tenon type underwater acoustic transducer. From the appearance, the mortise-and-tenon piezoelectric module is produced by stacking the mortise-and-tenon units, and the rubber unit in the middle is used to connect the upper and lower mortise-and-tenon piezoelectric modules and also plays a decoupling function. Figure 2 for Figure 1 A three-dimensional structure of a transceiver-transmitter-mortise-and-tenon type underwater acoustic transducer is composed of a watertight layer 1, a tenon unit 2, a first electrode plate 3, an electrode lead 4, a second electrode plate 5, a second rubber unit 6, a first rubber unit 7, a tenon unit 8, a backing layer 9, a rear end cover 10, a multi-core cable 11, a piezoelectric column 12, a rigid polymer 13, an air gap 14, and a piezoelectric substrate 15. The watertight layer 1 is tightly wrapped around a complex consisting of the mortise and tenon piezoelectric modules 1 and 2, the electrode plates 3 and 5, the electrode leads 4, the rubber units 6 and 7 backing layer 9, and the rear end cover 10 to achieve sound transmission and waterproof effects; the electrode leads 4 are respectively fixed on the electrode plates 3 and 5 of the mortise and tenon units, and the electrode plates 3 and 5 of the mortise and tenon units, for conducting the vibration of the piezoelectric components and external electrical signals; the rubber units 6 and 7 are fixed between the first electrode plate 3 and the second electrode plate 5 between the mortise and tenon units 2 and 8; the backing layer 9 is fixed between the rear end cover 10 and the mortise and tenon units 2 and 8, acting as a mechanical support and eliminating back noise signals; the multi-core cable 11 is fixed in the hole groove of the rear end cover, and the cable contains multiple leads for connecting and leading out all the above-mentioned electrode leads 4.

[0041] Figure 3 Schematic diagram of the three-dimensional structure of the tenon unit 2. The tenon unit 2 is an inward convex structure, which consists of a first electrode plate 3, a second electrode plate 5, a piezoelectric column 12, a rigid polymer 13, an air gap 14 and a piezoelectric substrate 15. Among them, the first electrode plate 3, the piezoelectric column 12, the rigid polymer 13 and the piezoelectric substrate 15 together constitute a rigid tenon module in the tenon unit 2, which has high compressive resistance under the joint action of the rigid polymer 13 and the piezoelectric substrate 15, and the transducer can meet the requirements of a high-intensity mechanical emission unit.

[0042] Figure 4 Schematic diagram of the three-dimensional structure of the mortise unit 8. The mortise unit 8 is a concave structure, which can be mechanically matched with the convex tenon unit 2. Similarly, the mortise unit 8 is also composed of a first electrode plate 3, a second electrode plate 5, a piezoelectric column 12, a rigid polymer 13, an air gap 14 and a piezoelectric substrate 15. Except for the difference in shape, it is the same as the tenon unit configuration.

[0043] The rigid tenon structure in the tenon-shaped unit 2 and the rigid mortise structure in the mortise-shaped unit 8 constitute a transducer transmitting unit (both composed of a piezoelectric column 12, a rigid polymer 13 and a piezoelectric substrate 15), and its top view is shown in FIG. Figure 5 As shown. The two structures belong to the same 1-3 type structure in terms of the connection structure, and have good thickness vibration mode and stability; similarly, the air gap unit in the tenon unit 2 and the air gap unit in the mortise unit 8 constitute the receiving unit of the transducer (all composed of piezoelectric small pillars 12, air gaps 14 and piezoelectric substrates 15). Using air gaps as fillers can reduce the acoustic energy loss caused by lateral coupling and make the thickness mode more concentrated.

[0044] Embodiment 1:

[0045] like Figure 1 and Figure 2 As shown, the mortise and tenon type underwater acoustic transducer disclosed in this embodiment is composed of a watertight layer 1, a mortise and tenon type piezoelectric module, a backing layer 9, a rear end cover 10, and a multi-core cable 11.

[0046] like Figure 2 As shown, the tenon-shaped piezoelectric module is composed of a tenon unit 2, a tenon unit 8, an electrode unit (3 and 5) and a rubber unit (6 and 7). The module can be used to generate sound waves as the core part of the transducer. The tenon unit 2 includes a rigid tenon module, an air gap unit and an electrode unit; the tenon unit is a middle convex structure, and the specific feature is that the thickness of the rigid tenon module is greater than that of the air gap unit.

[0047] like Figure 3 As shown, the rigid tenon module is composed of a first electrode plate 3 , a piezoelectric column 12 , a rigid polymer 13 and a piezoelectric substrate 15 .

[0048] The piezoelectric pillars 12 and the piezoelectric substrate 15 are made of the same material, and PZT ceramics and PMN-PT single crystals with good piezoelectricity can be used to ensure high-intensity emission and high-sensitivity receiving performance; the piezoelectric pillars 12 are a uniform periodic array and have exactly the same structural parameters.

[0049] The rigid polymer 13 may be made of epoxy resin or PMMA material with relatively high hardness, which is used to separate the small columns between the piezoelectric arrays and improve the stability and pressure resistance of the piezoelectric arrays.

[0050] The piezoelectric substrate 15 is used to connect all the piezoelectric columns 12 to further improve the stability and pressure resistance of the rigid tenon module; the piezoelectric substrate 15 includes two end surfaces, a piezoelectric surface and an electrode surface, wherein the piezoelectric surface is used to connect all the piezoelectric columns, and the electrode surface is used to transfer and receive charges; in addition, the aspect ratio of the piezoelectric column 12 is not less than 4:1.

[0051] The ratio of the gap to the width of the piezoelectric pillar 12 is between 0.24 and 0.35 to ensure that the volume fraction of the piezoelectric phase is controlled within the range of high electromechanical conversion capability of the material.

[0052] The thickness of the piezoelectric substrate 15 is within 10% of the total thickness of the tenon-shaped unit 2 , which not only greatly weakens the lateral coupling but also retains the compressive resistance of the piezoelectric material.

[0053] The air gap unit is composed of a piezoelectric column 12 and a piezoelectric substrate 15 , wherein the piezoelectric column 12 and the piezoelectric substrate 15 in the air gap unit are made of exactly the same material as the piezoelectric column 12 and the piezoelectric substrate 15 of the rigid tenon module, but do not contain the rigid polymer 13 .

[0054] like Figure 4 As shown, the mortise-shaped unit 8 comprises a rigid mortise-shaped module, an air gap unit and an electrode unit; the mortise-shaped unit 8 is a middle concave structure, and the specific feature is that the thickness of the rigid mortise-shaped module is smaller than that of the air gap unit.

[0055] The piezoelectric substrate 15 of the mortise unit and the piezoelectric substrate 15 of the tenon unit are made of exactly the same material and structural parameters. Preferably, the thickness of the piezoelectric substrate of the mortise unit is within 10% of the total thickness of the mortise unit.

[0056] The rigid mortise module is composed of a piezoelectric column 12 , a rigid polymer 13 and the piezoelectric substrate 15 .

[0057] The piezoelectric small column 12 in the rigid mortise module and the piezoelectric small column 12 in the rigid tenon module are made of the same piezoelectric material; the rigid polymer 13 of the rigid mortise module is completely the same as the rigid polymer 13 of the rigid tenon module.

[0058] The air gap unit of the mortise-shaped unit 8 and the air gap unit of the tenon-shaped unit 2 adopt exactly the same configuration, including material and structure.

[0059] The rigid tenon module and the rigid mortise module serve as the transmitting unit of the transducer to realize the high mechanical strength broadband transmission of the transducer; the air gap unit of the tenon unit 2 and the mortise unit 8 serves as the receiving unit of the transducer for high sensitivity reception of the transducer to meet the transceiver transceiver integrated function. Preferably, the piezoelectric small column 12 in the rigid mortise module is similar to the rigid tenon module by periodic arrangement, and the aspect ratio is not less than 4:1, and the structural dimensions are also the same.

[0060] The ratio of the gap to the width of the piezoelectric pillar 12 of the rigid mortise module is between 0.24 and 0.35 to ensure that the volume fraction of the piezoelectric phase is controlled within the range of high electromechanical conversion capability of the material.

[0061] The difference in thickness between the piezoelectric pillar 12 of the rigid mortise module and the piezoelectric pillar 12 of the rigid tenon module is no more than 1 mm.

[0062] The tenon-shaped units 2 and mortise-shaped units 8 are stacked in the thickness direction, wherein the protruding portion of the rigid tenon module should completely fit with the recessed portion of the rigid tenon structure.

[0063] The rubber unit is divided into a first rubber unit 6 and a second rubber unit 7, and both are made of decoupling material rubber with low Young's modulus, such as cork rubber, silicone rubber, etc.; the first rubber unit 6 is a square solid structure, used to connect the rigid tenon module and the rigid mortise module; the second rubber unit 7 is a hollow square structure, used to connect the tenon unit 2 and the air gap unit in the mortise unit 8.

[0064] The thickness of the rubber unit does not exceed 1 mm, and the outer dimensions are adapted to the tenon unit 2 and the mortise unit 8 .

[0065] The electrode unit includes a first electrode plate 3, a second electrode plate 5 and an electrode lead 4. The electrode unit can be made of metal materials such as silver, copper, platinum, etc. with good conductivity, and the thickness does not exceed 0.5mm; the two-dimensional plane size and structure of the first electrode plate 3 and the second electrode plate 5 are respectively the same as those of the first rubber unit 6 and the second rubber unit 7, wherein the top surfaces of the rigid tenon module and the rigid mortise module are covered with the first electrode plate 3, and the air gap units of the tenon unit 2 and the mortise unit 8 are covered with the second electrode plate 5. The electrode lead 4 is fixed to the surface of the first electrode plate 3 and the second electrode plate 5, respectively, and is used to transmit and extract the current of the electrode unit, and can be made of metal materials with good conductivity.

[0066] The backing layer 9 is made of a foam material with high hardness and more pores, which can support the mortise and tenon piezoelectric module and filter out the clutter generated by the back of the transducer.

[0067] The watertight layer 1 is made of a polyurethane material with strong matching and good sound permeability, which can effectively reduce the reflection of sound wave energy; the thickness of the watertight layer 1 is within 1 / 4 to 3 / 4 of the wavelength.

[0068] The multi-core cable 11 is used to connect the electrode leads 4 to achieve independent control of each module of the mortise and tenon piezoelectric module.

[0069] The rear end cover 10 is used to lead out the multi-core cable 11 , and can be made of metal material. Its size is comparable to that of the backing layer 9 .

[0070] Embodiment 2:

[0071] Type 1-3 hydroacoustic transducers are in urgent need of breakthroughs in bandwidth expansion, because their limited operating frequency range makes it difficult to adapt to the detection and communication needs of complex underwater environments. Broadband hydroacoustic transducers can cover a wider range of frequencies, thereby improving signal transmission quality, reducing the impact of multipath effects, and improving the reliability of data transmission, which is particularly important for ocean detection and underwater communications. In addition, the market demand for integrated transmitting and receiving transducers is increasing. This integrated design not only reduces the size of the equipment and reduces the complexity of the system, but also improves the response speed and signal processing efficiency. In this regard, the present invention proposes to use a mortise and tenon structure to develop an integrated hydroacoustic transducer that takes into account both broadband transmission and high-sensitivity reception, aiming to solve the problems of the existing technology. The specific design process is as follows:

[0072] The general range of underwater high-frequency transducers is generally around 200kHz to 400kHz. The frequency constant of the PZT-epoxy composite unit is approximately 1500, so the thickness of the composite unit should be in the range of 3.75mm to 7.5mm. In this example, the thickness of the tenon unit 2 is 6.0mm, and the thickness of the mortise unit 8 is 5.5mm. The piezoelectric material is PZT-5A ceramics with good hardness and dual-purpose for transmission and reception. The rigid polymer 13 is 618 epoxy resin with good stability. The rubber unit (6 and 7) is made of 704 silicone rubber with strong viscosity and good decoupling. The electrode units (3 and 5) are made of thin metal copper foil (0.1mm).

[0073] A piezoelectric substrate 15 of a certain thickness can improve the stability of the piezoelectric composite material and make it have a certain compressive resistance, but too high a percentage of the substrate will lead to strong lateral coupling, thereby greatly reducing the electromechanical coupling coefficient. The present invention designs the ceramic substrates of the tenon unit 2 and the mortise unit 8 to be 0.5 mm, which does not exceed 10%.

[0074] When the aspect ratio of the piezoelectric material is lower than 3:1, lateral coupling will be induced, resulting in acoustic energy loss. Therefore, the width of the piezoelectric column 12 is set to 1 / 4 of the thickness (4:1), that is, 1 mm. Similarly, in order to obtain a higher electromechanical coupling coefficient, the ratio of the gap and width of the piezoelectric column 12 of the rigid tenon module should be between 0.24 and 0.35 to ensure that the volume fraction of the piezoelectric phase is controlled within the high electromechanical conversion capability range of the material. Therefore, the slit width is set to 0.3 mm.

[0075] To ensure uniformity of the composite material, the thickness of the air gap unit should be half of the overall thickness of the tenon unit 2 and the mortise unit 8, that is, 5.25 mm. At the same time, to ensure uniformity, the slit width is also set to 0.3 mm.

[0076] Considering that the thickness of the rubber units (6 and 7) does not exceed 1 mm, and the external dimensions are adapted to the tenon unit 2 and the mortise unit 8, the thickness of the silicone rubber gasket is set to 0.5 mm to ensure effective coupling of the mortise and tenon structure.

[0077] The manufacturing method of the integrated mortise and tenon type underwater acoustic transducer disclosed in this embodiment is specifically as follows:

[0078] Part 1: Preparation of tenon unit 2:

[0079] Step 1: Prepare a ceramic cutting skeleton. Take a 105mm×105mm×6mm piezoelectric material and fix it on the cutting machine sample stage, set the cutting depth to 5.5mm, the step to 1.3mm, and make the cutting blade cut along the horizontal and vertical directions, leaving 0.5mm of the piezoelectric substrate 15 to form a ceramic cutting skeleton.

[0080] Step 2: Filling with epoxy resin (rigid polymer 13). Prepare a certain amount of epoxy resin glue according to the ratio of epoxy resin: softener: curing agent = 10:1:1, and evenly fill it into the gaps of the cut skeleton. After vacuuming and draining bubbles, solidify and shape it to form a 1-3-2 rigid piezoelectric composite material.

[0081] Step 3: Prepare the tenon structure. Use a ruler to measure the position of the rigid tenon module in the 1-3-2 rigid piezoelectric composite material, cover the position with an opaque mask, and expose the rest of the composite material; fix the masked sample in the cutting machine again, set the cutting step to 1 / 3 of the blade width, and let the cutting blade grind away 0.25mm thickness to form the tenon structure.

[0082] Step 4: Prepare the air gap unit. Remove the mask, wash the composite material with the tenon structure prepared in step 3 with ethanol, and fix it on the cutting machine sample table again. Set the cutting depth to 5.25mm and the step to 1.3mm, so that the cutting blade can cut off the epoxy resin outside the tenon structure horizontally and vertically to form an air gap unit. The tenon-shaped unit 2 at this time has the following characteristics: a raised rigid tenon module in the middle, surrounded by a uniform array of piezoelectric columns 12, and an air gap 14 between the arrays;

[0083] Step 5: Covering electrodes. Take the customized square copper foil plate (first electrode plate 3) and the round copper foil plate (second electrode plate 5), paste them to cover the top surface of the rigid tenon module and the top surface of the air gap unit, and weld the leads to the two end surfaces. At this point, the tenon unit 2 is ready.

[0084] Part II: Preparation of mortise unit 8:

[0085] Step 1: Prepare a ceramic cutting skeleton. Take a 105mm×105mm×5.5mm piezoelectric material and fix it on the cutting machine sample stage, set the cutting depth to 5mm, the step to 1.3mm, and make the cutting blade cut along the horizontal and vertical directions respectively, leaving 0.5mm of the piezoelectric substrate 15 to form a ceramic cutting skeleton.

[0086] Step 2: Fill with epoxy resin. Prepare a certain amount of epoxy resin glue according to the ratio of epoxy resin: softener: curing agent = 10:1:1, and evenly fill it into the gaps of the cut skeleton. After vacuuming and draining bubbles, solidify and shape it to make a 1-3-2 rigid piezoelectric composite material.

[0087] Step 3: Prepare the mortise structure. Use a ruler to measure the position of the rigid mortise module in the 1-3-2 rigid piezoelectric composite material, and use an opaque mask to cover the part outside the rigid mortise module; fix the sample covered with the mask in the cutting machine again, set the cutting step to 1 / 3 of the blade width, the cutting depth to 0.25mm, and use the cutting blade to grind the exposed part in the middle of the material to form a mortise structure.

[0088] Step 4: Prepare the air gap unit. Remove the mask, wash the composite material with the mortise structure prepared in step 3 with ethanol, and fix it on the cutting machine sample stage again. Set the cutting depth to 5.25mm and the cutting step to 1.3mm, so that the cutting blade can cut off the epoxy resin outside the mortise structure horizontally and vertically to form an air gap unit. The mortise unit 8 at this time has the following characteristics: a concave rigid mortise module in the middle, surrounded by uniform piezoelectric small columns 12, and an air gap 14 between the arrays;

[0089] Step 5: Covering electrodes. Take the customized square copper foil plate (first electrode plate 3) and the round copper foil plate (second electrode plate 5), paste them on the top surface of the rigid mortise module and the top surface of the air gap unit, and weld the leads on the two end surfaces. At this point, the mortise unit 8 is prepared.

[0090] Part 3: Making a mortise and tenon-shaped piezoelectric module:

[0091] Take the square silicone rubber gasket (first rubber unit 6) and the round silicone rubber gasket (second rubber unit 7). Use glue to fix the square silicone rubber gasket in the middle of the square copper foil plate of the tenon unit 2 and the mortise unit 8, and use glue to fix the round silicone rubber gasket in the middle of the round copper foil plate of the tenon unit and the mortise unit. At this point, the tenon-and-mortise piezoelectric module is ready.

[0092] Part 4: Paste the backing layer:

[0093] The backing layer 9 is pasted on the bottom of the mortise and tenon type piezoelectric module, and all the electrode leads 4 are pasted on the outside of the backing after being marked.

[0094] Part 5: Paste the rear cover and fix the multi-core cable:

[0095] The multi-core cable 11 is passed through the slot of the rear end cover 10 and connected to all the electrode leads 4 ; the rear end cover 10 is glued and fixed to the backing layer 9 .

[0096] Part VI: Encapsulated polyurethane (watertight layer 1):

[0097] After the adhesive of the fifth part is cured, it is fixed in the adhesive sealing mold, and polyurethane adhesive is injected and cured before demoulding. Thus, the production of a transceiver-transmitter-integrated tenon-and-mortise type underwater acoustic transducer is completed.

[0098] The following is a performance test of the mortise and tenon type underwater acoustic transducer prepared in this embodiment in combination with the specific design. In this example, PZT-5A is selected as the piezoelectric material, 618 epoxy resin and 704 silicone rubber are the rigid polymer phase and silicone rubber gasket respectively, and the material parameters are shown in Table 1 below:

[0099] Table 1. Material parameters of PZT-5A, epoxy resin and silicone rubber

[0100]

[0101] The transducer is simulated using finite element analysis. Figure 6 The schematic diagram of the underwater simulation structure of the transducer in this embodiment is shown in Figure 1. The simulation structure consists of a 200mm far water area, a 20mm near water area, an acoustic absorption boundary, and a transducer optimization structure. To facilitate calculation and meshing, the watertight layer 1 and the backing layer 9 are optimized in this example. In the simulation post-processing module, the electrical admittance information of the transducer transmitting module is read and plotted as shown in Figure 1. Figure 7 The simulation results of admittance-frequency are shown in Figure 2. Figure 7 It can be seen from the admittance results in that the mortise and tenon transducer has two thickness resonance modes. When two piezoelectric units with similar thickness are stacked longitudinally, the coupled resonance can be effectively excited and the half-power point bandwidth can be increased to 48 kHz, which verifies the rationality of the design idea of ​​the present invention.

[0102] At the far water boundary, the sound pressure at the farthest point from the acoustic center of the transducer axis is extracted and substituted into equations (1) and (2) to obtain the transmitting voltage response (S) of the transducer in water. v ) and receiving voltage sensitivity (M v ) changes with frequency.

[0103]

[0104] In the above formulas (1) and (2), P a is the sound pressure in the far water area, r is the radius of the water area, V is the transducer voltage (1V simple harmonic AC voltage), ρ is the water density (1000kg / m3 ), f is the transducer frequency.

[0105] Figure 7 The relationship between the transmitting voltage response and frequency of the middle transmitting unit of the transducer is given. As the frequency increases, the transmitting voltage response of the transducer first increases to a peak value and then decreases, and a peak value of 159.3dB is obtained near the resonant frequency of 264kHz. The curve has a wide frequency band and a flat trend, and has good broadband transmission performance; Figure 8 is the relationship between the receiving voltage sensitivity and frequency of the transducer receiving unit. The curve reaches a peak value of -206.0dB near the anti-resonance of the transducer, and the curve trend is relatively flat, and the receiving performance is better than that of the current transducer (below -210dB). In this example, the underwater acoustic transducer designed by the present invention can realize the integrated multi-purpose function of the transducer with the help of the classical mortise and tenon structure, while also meeting the requirements of high mechanical strength and high broadband transmission capability, and has a high sensitivity perception effect, which has a great reference value for the development of a small-sized integrated transceiver underwater acoustic transducer.

[0106] The specific description above further illustrates the purpose, technical solutions and beneficial effects of the invention in detail. It should be understood that the above is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A transceiver-transmitter-tenon-and-mortise type underwater acoustic transducer, characterized in that: It includes a mortise and tenon piezoelectric module, a backing layer, a multi-core cable, a rear end cover and a watertight layer; The mortise and tenon piezoelectric module is mainly composed of a mortise unit, a tenon unit, an electrode unit and a rubber unit; The height of the middle part matrix of the tenon-shaped unit is higher than the height of the peripheral matrix, and the higher part is called the rigid tenon module; the rest is called the air gap unit; the rigid polymer is filled between the rigid tenon module arrays; the end surface of the tenon-shaped unit is covered with the electrode unit; the rigid tenon module is covered with the first electrode plate; the air gap unit is covered with the second electrode plate; the above electrode units are respectively led out with leads; The height of the matrix in the middle part of the mortise unit is lower than that of the peripheral matrix, and the concave part is called a rigid mortise module; the rest is called an air gap unit; the rigid polymer is filled between the rigid mortise module arrays; the end surface of the mortise unit is covered with an electrode unit; the rigid mortise module is covered with a first electrode plate; the air gap unit is covered with a second electrode plate; the above electrode units are respectively led out with leads; The tenon-shaped unit and the mortise-shaped unit are connected by the rubber unit; the rigid tenon module and the rigid mortise-shaped module are stacked longitudinally by the rubber unit to achieve multi-mode bandwidth expansion; The backing layer is fixed to the bottom of the mortise and tenon piezoelectric module to support the piezoelectric module and absorb clutter; the multi-core cable is fixed to the bottom of the backing layer, one end of which is connected to all the above leads, and the other end is led out from the inner side of the slot hole of the rear end cover; The watertight layer wraps the mortise and tenon-shaped piezoelectric module, the backing layer and the top end surface of the rear end cover.

2. The mortise and tenon type underwater acoustic transducer with integrated transmitter and receiver as claimed in claim 1, characterized in that: The rigid tenon module and the rigid mortise module serve as the transmitting unit of the transducer to realize the high mechanical strength broadband transmission of the transducer; the air gap unit of the tenon unit and the mortise unit serves as the receiving unit of the transducer for the high sensitivity reception of the transducer to meet the transceiver's integrated transmitting and receiving function.

3. The mortise and tenon type underwater acoustic transducer with integrated transmitter and receiver as claimed in claim 1 or 2, characterized in that: The material of the tenon-shaped unit and the mortise-shaped unit is selected from PZT ceramics or PMN-PT single crystal to ensure high-intensity emission and high-sensitivity receiving performance; and the small columns in the array have exactly the same structural parameters.

4. The mortise and tenon type underwater acoustic transducer with integrated transmitter and receiver as claimed in claim 1 or 2, characterized in that: The rigid polymer material is epoxy resin or PMMA material, which is used to separate the small columns between the piezoelectric arrays and improve the stability and pressure resistance of the piezoelectric arrays.

5. The mortise and tenon type underwater acoustic transducer with integrated transmitter and receiver as claimed in claim 1 or 2, characterized in that: The aspect ratio of the piezoelectric columns in the rigid tenon module and the rigid mortise module is not less than 4:1; the ratio of the width of the piezoelectric column to the width of the array gap is between 0.24 and 0.35 to ensure that the volume fraction of the piezoelectric phase is controlled within the high electromechanical conversion capability range of the material.

6. The mortise and tenon type underwater acoustic transducer with integrated transmitter and receiver as claimed in claim 1 or 2, characterized in that: The tenon-shaped units and mortise-shaped units are stacked in the thickness direction, wherein the protruding portion of the rigid tenon module should be completely matched with the recessed portion of the rigid tenon structure.

7. The mortise and tenon type underwater acoustic transducer with integrated transmitter and receiver as claimed in claim 1 or 2, characterized in that: The rubber unit is made of a decoupling material rubber with a low Young's modulus; the thickness of the connecting unit does not exceed 1 mm, and the outer dimensions are adapted to the tenon unit and the mortise unit.

8. The mortise and tenon type underwater acoustic transducer with integrated transmitter and receiver as claimed in claim 1 or 2, characterized in that: The electrode unit comprises a first electrode plate and a second electrode plate; the electrode unit is made of metal material with a thickness not exceeding 0.5 mm.

9. The transmitting and receiving integrated mortise and tenon type underwater acoustic transducer as claimed in claim 1 or 2, characterized in that: The backing layer is made of a foam material with relatively high hardness and relatively more pores; relatively high hardness means that the hardness is higher than a preset hardness threshold, and relatively more pores means that the number of pores is higher than a preset threshold; The rear end cover is made of metal material, and its outer dimensions are matched with the dimensions of the backing layer.

10. The mortise and tenon type underwater acoustic transducer with integrated transmitter and receiver as claimed in claim 1 or 2, characterized in that: The watertight layer is made of a polyurethane material with strong matching and good sound permeability; the thickness of the watertight layer is controlled within 1 / 4 to 3 / 4 wavelength; The multi-core cable is used to connect the electrode unit leads.

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