Small-size low-rigidity iron-gallium magnetostriction driving module and underwater acoustic transducer

Abstract

The invention discloses a small-size low-rigidity iron-gallium magnetostriction driving module and an underwater acoustic transducer. The iron-gallium magnetostriction driving module comprises an iron-gallium bent beam, a driving coil, a permanent magnet and a high-permeability transition block, the iron-gallium bent beam comprises a main beam, an auxiliary beam and fixed end blocks which are integrated, the main beam and the auxiliary beam are arranged in parallel, the two ends of the main beam and the two ends of the auxiliary beam are connected through the fixed end blocks, the fixed end blocks downwards extend out of beam feet, and the beam feet exceed the lower edge of the auxiliary beam and serve as the open end and the tail end of a magnetic induction line of a conduction bias magnetic field. A boss is upwards arranged in the middle of the main beam, and a connecting hole is reserved in the middle of the boss; the driving coil comprises main beam coils and auxiliary beam coils, the main beam coils are wound on the main beams on the two sides of the boss respectively, and the auxiliary beam coils are wound on the auxiliary beams. According to the driving module, through the low-rigidity bending mode design and the dynamic and static separated magnetic circuit design, the double breakthrough that the resonant frequency of the underwater acoustic transducer driving part body is greatly reduced and the height size is synchronously reduced is achieved.

Description

Technical Field

[0001] This invention relates to the field of acoustic transducer technology, and particularly to the field of driving materials for underwater acoustic transducers. Specifically, it relates to a small-size, low-stiffness iron-gallium magnetostrictive driving module and an underwater acoustic transducer using the driving module. Background Technology

[0002] As is well known, the lower the frequency of sound waves, the less energy is lost in the medium, and thus the farther they can travel in the ocean. In recent years, the demand for underwater sound wave emission in the low-frequency band (100Hz~500Hz) has been gradually increasing, and the requirements for the size of the sound source have become increasingly stringent, with the general desire to achieve low-frequency sound emission capability with a very limited size.

[0003] The driving material is the core component of an acoustic transducer. Aside from sound sources driven by electromagnetic force, the driving materials commonly used in acoustic transducers mainly include: 1. Piezoelectric driving materials, such as PZT piezoelectric ceramics, relaxor ferroelectric single crystals, antiferroelectric ceramics, and novel lead-free ceramics; 2. Magnetostrictive materials, such as rare-earth super-magnetostrictive material Terfenol-D and iron-gallium (Fe-Ga) magnetostrictive materials. However, currently, PZT piezoelectric ceramic materials, with their stable performance and mature production and supply system, consistently rank first in both the number of applications and the types of applications in the field of active materials for underwater acoustic transducers.

[0004] Currently, in the application of low-frequency high-power transducers, existing driving technologies almost all rely on stacking materials along their thickness (or height) to form a columnar structure for longitudinal vibration, or stacking and interlocking materials at a certain angle to form a ring for radial vibration (which is essentially also vibration along the material's thickness). These forms the basic driving unit of the transducer. Regarding the materials themselves, whether piezoelectric or magnetostrictive, they all utilize the stretching and strain of the material itself in the direction of the electric (magnetic) field to generate the external driving force. This results in a situation where, for the same length, the resonant frequency of a driving unit constructed in a longitudinal stacking configuration is positively correlated with the longitudinal wave velocity of the material. The lower the longitudinal wave velocity, the lower the resonant frequency of the driving unit, making it easier to achieve low-frequency and miniaturized transducer designs. Taking the most commonly used PZT-4 piezoelectric ceramic and rare-earth magnetostrictive material as examples, the longitudinal wave velocities of the two materials are 4300 m / s and 1750 m / s, respectively. When these two materials are fabricated into cylindrical rods (thin rods with a large length-to-diameter ratio) with a height of 40 mm, the first-order resonant frequencies of the two rods are approximately 35.5 kHz and 18.2 kHz, respectively. Rare-earth magnetostrictive material has almost the lowest longitudinal wave velocity among currently available high-power underwater acoustic transducer driving materials. Therefore, the lower limit of the material's sound velocity is difficult to overcome, which also makes it difficult to overcome the lower limits of the low-frequency range and size of underwater acoustic transducers.

[0005] At the same time, conventional drive materials also exhibit the following characteristics: they are mostly formed by powder pressing and single-crystal or polycrystalline growth. Most of these materials are brittle in texture, with disadvantages such as being resistant to compression but not to tension, being fragile, and not easy to process. Therefore, their application can almost only be carried out in the form of longitudinal stacking in the thickness or height direction as mentioned above.

[0006] Iron-gallium magnetostrictive materials are currently in an awkward position in the transducer field, due to their saturation magnetostriction coefficient. (Approximately 300~450ppm) is less than that of the rare-earth magnetostrictive material Terfenol-D ( Approximately 2000 ppm); while in comparison, piezoelectric ceramic materials with similar strain levels ( (Approximately 400 ppm), and it is not as mature, stable, or convenient to use as the ceramic industry. Even though many scholars at home and abroad have conducted relevant research on it and applied it to the field of transducers, it lacks outstanding advantages and has always been difficult to promote on a large scale.

[0007] However, iron-gallium magnetostrictive materials have their own unique characteristics: 1) Medium to high magnetostrictive strain and low working magnetic field can reduce the size of the coil and achieve miniaturization.

[0008] 2) The operating temperature is high, the temperature coefficient of magnetostrictive strain is very small, and the temperature stability is good.

[0009] 3) It has high strength, making it sturdy and robust when used to manufacture various devices.

[0010] 4) The plasticity can be improved by alloying and other technical means. Then, the iron gallium material can be manufactured into rods, wires, cold-rolled plates, strips or thin films using traditional material processing techniques. It can also be welded to other materials using traditional welding techniques. It can manufacture devices of any shape, with high plasticity and good processability.

[0011] To address the limitations of existing underwater acoustic transducers in terms of low-frequency and size constraints, the limitations of traditional driving material applications, and the difficulty in leveraging the unique characteristics of iron-gallium magnetostrictive materials (EGMTs), this invention designs a low-stiffness EGMT miniature driving module to replace traditional driving materials in underwater acoustic transducers. This invention fully utilizes the unique advantages of EGMTs, such as plasticity, ease of processing, high structural strength, and miniaturization, achieving lower resonant frequencies at a smaller scale, thus overcoming the low-frequency and size limitations of traditional materials. Furthermore, this invention breaks away from the traditional longitudinal driving method of magnetostrictive materials. By utilizing the ease of processing and high structural strength of EGMTs, the material is fabricated into a curved beam, replacing the traditional thickness-mode longitudinal driving method with a curved mode application. This allows the characteristics of EGMTs to be fully utilized, overcoming the technical challenge of synergistic development in low-frequency and miniaturization of underwater acoustic transducers under traditional driving methods. Summary of the Invention

[0012] The purpose of this invention is to overcome the technical challenge of the inability to simultaneously achieve low-frequency and miniaturization of the drive component due to the brittleness of traditional driving materials such as piezoelectric ceramics and rare-earth magnetostrictive materials, which primarily employ longitudinal driving. This is achieved by providing a small-size, low-stiffness iron-gallium magnetostrictive drive module. Utilizing the unique advantage of iron-gallium material's high plasticity, it is processed into an irregular structure and uses a bending mode to provide longitudinal driving force. This invention achieves a dual breakthrough: a significant reduction in the resonant frequency and a simultaneous reduction in the height of the underwater acoustic transducer drive component, providing crucial technical support for the low-frequency and miniaturization of underwater acoustic transducers.

[0013] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows: A small-size, low-stiffness iron-gallium magnetostrictive drive module, the iron-gallium magnetostrictive drive module comprising: an iron-gallium bending beam, a drive coil, a permanent magnet, and a high-permeability transition block; The iron-gallium bent beam includes an integrated main beam, a secondary beam, and a fixed end block. The main beam and the secondary beam are arranged in parallel, and the two ends of the main beam and the secondary beam are connected by the fixed end block. The fixed end block extends downwards from the beam foot, which extends beyond the lower edge of the secondary beam, serving as the beginning and end of the magnetic field lines for conducting the bias magnetic field. A boss is provided in the middle of the main beam, and a connection hole is reserved in the middle of the boss; The drive coil includes a main beam coil and a secondary beam coil. A main beam coil is wound on the main beam on both sides of the boss, and a secondary beam coil is wound on the secondary beam. The aforementioned iron-gallium bending beams are arranged in pairs, symmetrically arranged vertically, with the main beam facing outwards and the beam feet facing inwards. The permanent magnet is disposed between the legs of the two iron-gallium bent beams, and the high-permeability transition block is disposed between the permanent magnet and the legs of the iron-gallium bent beams.

[0014] The iron-gallium magnetostrictive drive module also includes a support frame and a prestressed pressure plate; the support frame, viewed from above, is in the shape of an "I", with slots on the left and right openings for inserting and fixing permanent magnets, and auxiliary support arms extending upward and downward from the two ends of the slots, with threaded holes on each support arm; A gallium iron oxide magnetostrictive drive module is equipped with two prestressed pressure plates, one on each side. The main body of the prestressed pressure plate is a square thick plate with two small square feet on the top and bottom. The gallium iron oxide bending beam is embedded to form a normal fit, which is used to position the gallium iron oxide bending beam. The prestressed pressure plate is provided with through holes for threaded holes of the support arm, which are used to insert screws for fixing. The length of the gallium iron oxide bending beam must exceed the length of the support frame. The excess part is the compression amount. Tightening the screws provides prestress to the gallium iron oxide bending beam.

[0015] The present invention also provides an underwater acoustic transducer, wherein the underwater acoustic transducer adopts the above-mentioned iron gallium magnetostrictive drive module.

[0016] Preferably, the underwater acoustic transducer is a composite rod transducer, a bending transducer, or an inlaid ring transducer.

[0017] Specifically, the iron-gallium magnetostrictive drive module provided by the present invention includes: an iron-gallium bending beam, a drive coil, a permanent magnet, a high-permeability transition block, a support frame, and a prestressed pressure plate, wherein: The iron-gallium bending beam is long and narrow, processed into an irregular shape, symmetrical about the longitudinal axis, and has two parallel beams arranged in the transverse direction, with the upper beam being the main beam and the lower beam being the secondary beam. The aforementioned iron-gallium bent beam has two fixed end blocks extending from the left and right sides of the two beams. The fixed end blocks extend downwards from the beam feet, beyond the lower edge of the sub-beam by a certain distance. The function of the beam feet is to support and position the beams, and they are also the beginning and end of the magnetic field lines that conduct the bias magnetic field. The aforementioned iron-gallium bending beam has a boss in the middle of the main beam, which is the connection point for the drive module to output force and displacement. A connection hole, such as a countersunk hole or a threaded hole, is reserved in the middle of the boss for connecting other components. The aforementioned iron-gallium bent beam consists of multiple stacked iron-gallium sheets in the thickness direction, or it can be divided by wire cutting of a single material. The sheets or the gaps between the sheets are separated by insulating materials or films. This is because iron-gallium material has high magnetic permeability and low eddy current cutoff frequency. The sheets can reduce eddy current losses, reduce heat generation, and improve efficiency.

[0018] The driving coil is made of common insulated wire or enameled wire, and is directly wound on the main beam and secondary beam of the iron-gallium bent beam. Due to the obstruction of the middle boss on the main beam, the coil is divided into left and right parts, while the coil is wound on the secondary beam without obstruction. The drive coil, the main beam coil and the secondary beam coil should be in opposite directions. When current flows through the coil, induced magnetic fields in opposite directions are generated in the main beam and the secondary beam. The magnetic field flows from the main beam into the secondary beam at one end of the beam and from the secondary beam into the main beam at the other end. A closed magnetic circuit is formed between the two beams. The permanent magnet can be made of neodymium iron boron, samarium cobalt, etc., and is shaped like a square sheet with magnetization in the thickness direction. It is used to provide a bias magnetic field for the iron gallium bent beam, so that the two beams of the iron gallium material are pre-stretched.

[0019] The high-permeability transition block is made of electrical pure iron and is shaped as a trapezoidal sheet. Its lower surface is comparable in size to the magnetic pole face of the permanent magnet, and its upper surface is comparable in size to the bottom surface of the iron-gallium bent beam. The middle is naturally laid out into a trapezoidal shape. The high-permeability transition block is placed between the permanent magnet and the foot of the iron-gallium bent beam to achieve a natural transition between surfaces of different sizes and to transmit the magnetic field lines generated by the permanent magnet into the iron-gallium material.

[0020] As an improvement to the aforementioned underwater acoustic transducer drive component, the iron-gallium bent beam consists of two pieces arranged symmetrically, with the main beam facing outwards and the beam feet facing inwards.

[0021] As an improvement to the aforementioned underwater acoustic transducer drive component, the high-permeability transition blocks are arranged in groups of four and are connected to the four beam legs of the two iron-gallium bent beams respectively.

[0022] As an improvement to the aforementioned underwater acoustic transducer drive component, the permanent magnet is arranged in pairs, with one on each side, placed between the facing beam feet of the two upper and lower iron-gallium bent beams and the high-permeability transition blocks. The four high-permeability transition blocks and the two iron-gallium bent beams are attracted together by magnetism to form a whole.

[0023] As an improvement to the aforementioned underwater acoustic transducer drive component, as shown in Figure 4(a), the permanent magnets on the left and right sides have opposite magnetization directions. If the north pole (N pole) of the left permanent magnet faces upward and the south pole (S pole) faces downward, then the south pole (S pole) of the right permanent magnet faces upward and the north pole (N pole) faces downward. Thus, the bias magnetic field provided by the permanent magnets is such that the magnetic field lines enter the upper iron-gallium curved beam from the north pole (N pole) of the left permanent magnet through the high permeability transition block on the upper left side, run parallel from left to right through the main and secondary beams, then through the high permeability transition block on the upper right side, and return to the south pole (S pole) of the right permanent magnet. The opposite is true below: the magnetic field lines enter the lower iron-gallium curved beam from the north pole (N pole) of the right permanent magnet through the high permeability transition block on the lower right side, run parallel from right to left through the main and secondary beams, then through the high permeability transition block on the lower left side, and return to the south pole (S pole) of the left permanent magnet. The whole structure forms a closed magnetic loop, which is the bias magnetic field, also known as the static magnetic loop.

[0024] As an improvement to the aforementioned underwater acoustic transducer drive component, as shown in Figure 4(b), the drive coil is wound on four beams of two iron-gallium curved beam components. The magnetic field direction of the main beam coil of the upper iron-gallium curved beam is from left to right, and the magnetic field direction of the secondary beam coil is from right to left, forming a magnetic circuit; the magnetic field direction of the main beam coil of the lower iron-gallium curved beam is from right to left, and the magnetic field direction of the secondary beam coil is from left to right, forming a magnetic circuit. This is the drive magnetic field, also known as the dynamic magnetic circuit.

[0025] As an improvement to the aforementioned underwater acoustic transducer drive component, the drive module's magnetic circuit is characterized by the following: the initial direction of the main beam's dynamic magnetic circuit is the same as the direction of the static magnetic circuit, resulting in superposition and enhancement of the magnetic field within the main beam, causing the main beam to elongate; the initial direction of the secondary beam's dynamic magnetic circuit is opposite to the direction of the static magnetic circuit, resulting in cancellation and weakening of the magnetic field within the secondary beam, causing the secondary beam to contract; the extension and contraction of the main and secondary beams together cause the main beam to bend outwards; under the dynamic driving action of the drive coil, the main beam bends and vibrates inwards and outwards, inputting force and displacement to the outside.

[0026] As an improvement to the aforementioned underwater acoustic transducer drive component, the drive module presents a magnetic circuit with separate dynamic and static magnetic circuits. The purpose is to prevent the dynamic magnetic circuit from passing through a high-resistivity permanent magnet material, thereby greatly reducing the magnetic resistance of the dynamic magnetic circuit. This allows for the provision of a suitable driving magnetic field for the iron-gallium material with a smaller current and fewer coil turns, thus reducing the size of the drive coil.

[0027] As an improvement to the aforementioned underwater acoustic transducer drive component, the drive component also includes a support frame, two prestressed pressure plates, and screws. The support frame, viewed from above, is shaped like an "I". Suitable slots are machined on the left and right slots for inserting and fixing two permanent magnets. Four auxiliary support arms extend upward and downward from the two feet of the slots. Each support arm is machined with threaded holes, with a total of eight symmetrical holes on both sides.

[0028] As an improvement to the aforementioned underwater acoustic transducer drive component, the prestressed pressure plate is provided in pairs for each drive component, one on the left and one on the right. The main body is a square thick plate with rounded corners. Two small square feet are provided at the top and bottom, which can be embedded to form a common fit for positioning the iron gallium bending beam. The four corners are fitted with the threaded holes of the support arm of the aforementioned support frame, and four through holes are provided for screws to pass through. In the design dimensions, the length of the iron gallium bending beam needs to exceed the total length of the support frame by about 1 mm. The excess part is the compression amount. Tightening the screws can provide prestress (pressure) to the iron gallium material. The prestress can improve the magnetostrictive ability of the iron gallium material and enhance the output displacement.

[0029] Compared with the prior art, the advantages of the present invention are: This invention discloses a small-size, low-stiffness magnetostrictive drive module. Utilizing the plasticity of iron-gallium materials, a novel drive module for longitudinal bending mode actuation is designed. Compared to traditional piezoelectric ceramic stacks and rare-earth super-magnetostrictive drive rod stacks, the stiffness of this module stack is significantly reduced, substantially lowering the lower limits of resonant frequency and size in existing drive technologies. The low-stiffness magnetostrictive drive module exhibits good adaptability. In common low-frequency underwater acoustic transducer structures, such as composite rods, rings, and bending transducers, it can be designed and used with the original drive method or replace existing piezoelectric ceramic drive stacks or rare-earth super-magnetostrictive drive rod stacks in situ. Underwater acoustic transducers designed using this novel drive module can further reduce the resonant frequency and overall size of the transducer, opening up a new drive technology pathway for low-frequency and miniaturized underwater acoustic transducers. Attached Figure Description

[0030] Figure 1 This is an overall diagram of a low-stiffness iron-gallium magnetostrictive drive module; Figure 2 This is a structural diagram of the core components of the drive module; Figure 3 This is a structural diagram of the supporting frame; Figure 4(a) is the static magnetic circuit diagram of the core component under a bias magnetic field; Figure 4(b) is the dynamic magnetic circuit diagram of the core component under the driving magnetic field; Figure 5(a) is a schematic diagram of the drive module adapting to the transducer structure scenario - (composite rod structure). Figure 5(b) is a schematic diagram of the drive module adapting to the transducer structure scenario - (Type IV bending tension structure). Figure 5(c) is a schematic diagram of the drive module adapting to the transducer structure scenario - (inlaid circular structure). Figure label: 1. Iron-gallium bending beam; 2. Drive coil; 2a. Main beam coil; 2b. Secondary beam coil; 3. Permanent magnet; 4. High permeability transition block; 5. Support frame; 6. Prestressed pressure plate. Detailed Implementation

[0031] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0032] Example 1 The iron-gallium magnetostrictive drive module provided in this embodiment includes the following core components: two iron-gallium bending beams 1, a drive coil 2, two permanent magnets 3, and four high-permeability transition blocks 4. In addition to the core components, it also includes a support frame 5, two prestressed pressure plates 6, and corresponding mounting screws. When the drive module is working, an electrical signal is applied to the drive coil 2, which generates a dynamic magnetic field. This causes the main beam and secondary beam of the iron-gallium bending beam 1 to undergo elongation and shortening deformations, respectively, resulting in bending vibration of the main beam. Through the midpoint of the beam with the greatest deflection, a reciprocating driving force and displacement are output outwards. This structure has extremely low stiffness, and as a drive element for an underwater acoustic transducer, it can significantly reduce the operating frequency of the underwater acoustic transducer and decrease its size.

[0033] The iron-gallium bending beam 1 is long and symmetrical along the longitudinal axis. Two parallel crossbeams are arranged in the transverse direction, with the upper beam being the main beam and the lower beam being the secondary beam. Two fixed end blocks extend from the left and right sides of the two beams, and the fixed end blocks extend downwards to the beam feet for support, positioning and conduction of the bias magnetic field. The boss in the middle of the main beam is the connection point for the drive module to output force and displacement. When mechanically connected, glue should be applied to ensure a firm bond.

[0034] The iron-gallium bent beam 1, due to the high magnetic permeability and low eddy current cutoff frequency of iron-gallium material, must be formed into a thin sheet stack or cut by wire cutting in the thickness direction. The thin sheets or the gaps between the cut sheets are separated by insulating materials or films. The thickness of the active material sheet is about 1 mm, which can effectively reduce the eddy current loss and heat generation problem below 300 Hz.

[0035] The drive coil 2 consists of a main beam coil 2a and a secondary beam coil 2b, which are directly wound on the main beam and secondary beam of the iron-gallium bending beam. Since the coil is wound on the vibrating body, the edges and corners of the iron-gallium bending beam need to be polished smooth and a protective film needs to be applied before winding to prevent cutting and provide insulation. The main beam coil 2a and the secondary beam coil 2b should form magnetic fields with opposite directions. When current flows through the coil, induced magnetic fields with opposite directions are generated in the main beam and the secondary beam. The two beams are connected end to end to form a closed loop, thus forming a closed magnetic circuit.

[0036] The permanent magnet 3 can be made of neodymium iron boron, samarium cobalt, etc. Since the permanent magnet is not in the dynamic magnetic circuit, it does not require slicing. The permanent magnet 3 provides a bias magnetic field, and its remanent magnetic properties should be determined based on effective simulation calculations to provide an appropriate bias magnetic field for the iron-gallium material.

[0037] The high-permeability transition block 4 is made of pure electrical iron and is in the shape of a trapezoidal thin sheet. The size of its lower surface is equivalent to that of the magnetic pole surface of the permanent magnet 3, and the size of its upper surface is equivalent to that of the bottom surface of the beam foot of the iron-gallium bending beam 1. Since a suitable bias magnetic field needs to be provided for the iron-gallium bending beam 1, the magnetic pole area of the permanent magnet 3 may be larger. The trapezoidal high-permeability transition block 4 is used to gather magnetic induction lines, playing the role of magnetic circuit connection and reducing magnetic leakage caused by the area difference.

[0038] The support frame 5 is in the shape of a "work" character when viewed from above. The support frame 5 is the fixed and installation foundation of the entire structure. Suitable clamping grooves are processed in the left and right slots, and two permanent magnets 3 are inserted and fixed on the sides, which can limit the offset of the permanent magnet 3 in the up-down and front-back directions. Then, four high-permeability transition blocks 4 are adsorbed and installed on the four magnetic pole surfaces of the permanent magnet 3, and one iron-gallium bending beam 1 is adsorbed and installed on the top and bottom respectively. Four auxiliary support arms extend upward and downward from the two feet of the slot, and threaded holes are processed on each support arm. After a prestressed pressing plate 6 is installed on the left and right respectively, the small square feet on the prestressed pressing plate 6 just hold the iron-gallium bending beam 1 to prevent its front-back offset.至此,所有内部核心部件全部夹紧或固定完成。

[0039] This embodiment develops a new application method of iron-gallium magnetostrictive materials in underwater acoustic transducer driving materials, and proposes a driving method of longitudinal driving in bending mode by using the plastic characteristics of the materials. It overcomes the thorny problems that the traditional piezoelectric ceramic stack and rare-earth giant magnetostrictive rod driving stack can only use longitudinal mode driving due to brittleness, resulting in difficulty in breaking through the lower limit of the working frequency and difficulty in reducing the equipment size. At the same time, it expands the application prospects of iron-gallium magnetostrictive materials in the field of underwater acoustic transducers.

[0040] The following further describes this embodiment in conjunction with the accompanying drawings.

[0041] Reference Figure 1 , the low-rigidity magnetostrictive driving module consists of an internal core driving component and an external frame, and the driving module is in the shape of a cuboid as a whole. The iron-gallium bending beams 1 are arranged symmetrically up and down, with the main beams facing outwards, and the protrusions on the main beams are the external output points, one on each of the top and bottom. Therefore, the driving direction of the entire module is one-dimensional longitudinal driving in the up-down direction. When applied, multiple driving modules can be stacked along the height direction, and the bosses on the main beams are connected together one by one as connection points to form a long rod-shaped driving stack.

[0042] Reference Figure 2 , there is one iron-gallium bending beam 1 at the top and bottom of the core driving component respectively, and driving coils 2 are wound around the main beams and secondary beams respectively; the permanent magnets 3, one group of two, are placed on the left and right respectively between the opposite beam feet of the upper and lower iron-gallium bending beams together with the high-permeability transition blocks 4, and the four high-permeability transition blocks and the two iron-gallium bending beams are adsorbed to form a whole through magnetism.

[0043] Reference Figure 3The support frame structure includes a support frame 5 and prestressed pressure plates 6. The prestressed pressure plates 6 are installed on both sides of the support frame with screws. After tightening, the core drive component is completely fixed, and the iron-gallium bending beam 1 should be subjected to appropriate prestress. The support frame structure does not participate in vibration output.

[0044] Referring to Figure 4(a), which shows the static magnetic circuit diagram of the core component under a bias magnetic field, the north pole (N pole) of the left permanent magnet 3 faces upward and the south pole (S pole) faces downward, while the south pole (S pole) of the right permanent magnet 3 faces upward and the north pole (N pole) faces downward. Thus, the direction of the bias magnetic field provided by the permanent magnet 3 is such that the magnetic field lines enter the upper iron-gallium curved beam 1 from the north pole (N pole) of the left permanent magnet 3 through the high permeability transition block 4 on the upper left, run parallel from left to right through the main and secondary beams, then through the high permeability transition block on the upper right, and return to the south pole (S pole) of the right permanent magnet 3. The opposite is true for the lower part, where the magnetic field lines enter the lower iron-gallium curved beam from the north pole (N pole) of the right permanent magnet through the high permeability transition block 4 on the lower right, run parallel from right to left through the main and secondary beams, then through the high permeability transition block 4 on the lower left, and return to the south pole (S pole) of the left permanent magnet 3. The whole structure forms a closed magnetic loop, which is the bias magnetic field, also known as the static magnetic loop. The bias magnetic field makes the vibration of the iron-gallium bending beam more linear and the driving range wider.

[0045] Referring to Figure 4(b), which shows the dynamic magnetic circuit diagram of the core component under the driving magnetic field, a driving coil 2 is added compared to Figure 4(a). This driving coil is wound around four beams of the two iron-gallium bent beam components 1. The magnetic field direction of the main beam coil 2a of the upper iron-gallium bent beam 1 is from left to right, and the magnetic field direction of the secondary beam coil 2b is from right to left, forming a magnetic loop. Similarly, the magnetic field direction of the main beam coil 2a of the lower iron-gallium bent beam 1 is from right to left, and the magnetic field direction of the secondary beam coil 2b is from left to right, forming another magnetic loop. This is the driving magnetic field, also known as the dynamic magnetic loop. The separate design of the dynamic and static magnetic circuits greatly reduces the magnetic reluctance of the dynamic magnetic circuit, providing a suitable driving magnetic field for the iron-gallium material with a smaller current and fewer coil turns, thereby reducing the size of the driving coil 2.

[0046] Referring to Figures 5(a)-5(c), these are schematic diagrams of the application scenarios of this drive module, listing three common underwater acoustic transducer structures: Figure 5(a) shows a composite rod transducer with a frustum-shaped front radiator at the top. The end of the radiator is connected to a set of longitudinal drive oscillators composed of several cascaded iron-gallium magnetostrictive drive modules. A tail mass block is connected at the bottom. Under electrical signal drive, the cascaded drive modules provide vertical driving force and displacement, radiating acoustic energy outwards from the front radiator; Figure 5(b) shows a type IV bending transducer, also consisting of a set of... A longitudinally driven oscillator, composed of several cascaded iron-gallium magnetostrictive drive modules, pushes an elliptical shell along the major axis of an ellipse. The sound energy is amplified by the displacement of the elliptical shell and radiates outwards from the shell. Figure 5(c) shows a mosaic ring transducer, where wedge-shaped strips at a certain angle serve as a transition between two drive modules. Several sets of wedge-shaped strips and drive modules are connected end-to-end, finally forming a perfect circle. Under electrical signal drive, the drive modules provide driving force and displacement along the circumferential tangential direction. The entire ring then exhibits an expansion or contraction vibration mode (breathing mode) radially and radiates sound energy outwards. The application of this drive module is basically the same as that of traditional piezoelectric ceramic longitudinally driven oscillators or rare-earth rod driven oscillators. It can directly replace the original drive oscillator. This drive module has good adaptability and can be normally embedded in various traditional transducer structures. Simultaneously, the drive module has already applied material prestress, eliminating the need to apply additional prestress to the oscillator when constructing the transducer, simplifying a process. Because the stiffness of the drive module oscillator is extremely low, the operating frequency and size of the transducer can be significantly reduced. Compared to traditional piezoelectric ceramic driven composite rod transducers, the product of the resonant frequency and maximum size can be reduced by at least 70%, while for bending transducers and ring transducers it can be reduced by at least 40% to 50%. For existing rare-earth material driven transducers, a frequency and size breakthrough of over 30% to 60% is also achieved. Therefore, this invention overcomes the bottlenecks in the operating frequency and size of existing underwater acoustic transducers, laying a new technological foundation for low-frequency sonar equipment.

[0047] All aspects not described in detail in this invention can be covered using conventional technical knowledge in the field.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to the embodiments, those skilled in the art should understand that modifications or equivalent substitutions to the technical solutions of the present invention do not depart from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A small-size, low-stiffness iron-gallium magnetostrictive drive module, characterized in that, The iron-gallium magnetostrictive drive module includes: an iron-gallium bending beam, a drive coil, a permanent magnet, and a high-permeability transition block; The iron-gallium bent beam includes an integrated main beam, a secondary beam, and a fixed end block. The main beam and the secondary beam are arranged in parallel, and the two ends of the main beam and the secondary beam are connected by the fixed end block. The fixed end block extends downwards from the beam foot, which extends beyond the lower edge of the secondary beam, serving as the beginning and end of the magnetic field lines for conducting the bias magnetic field. A boss is provided in the middle of the main beam, and a connection hole is reserved in the middle of the boss; The drive coil includes a main beam coil and a secondary beam coil. A main beam coil is wound on the main beam on both sides of the boss, and a secondary beam coil is wound on the secondary beam. The aforementioned iron-gallium bending beams are arranged in pairs, symmetrically arranged vertically, with the main beam facing outwards and the beam feet facing inwards. The permanent magnet is disposed between the legs of the two iron-gallium bent beams, and the high-permeability transition block is disposed between the permanent magnet and the legs of the iron-gallium bent beams.

2. The iron-gallium magnetostrictive drive module according to claim 1, characterized in that, The iron-gallium bent beam is composed of multiple stacked iron-gallium sheets in the thickness direction or is divided by wire cutting of a single material, with insulating material or film separating the sheets or the gaps between the sheets.

3. The iron-gallium magnetostrictive drive module according to claim 1, characterized in that, The permanent magnet is made of neodymium iron boron or samarium cobalt, and is in the shape of a square sheet with magnetization in the thickness direction.

4. The iron-gallium magnetostrictive drive module according to claim 1, characterized in that, The high-permeability transition block is made of electrical pure iron and is shaped as a trapezoidal sheet. Its lower surface is comparable in size to the magnetic pole face of the permanent magnet, and its upper surface is comparable in size to the bottom surface of the iron-gallium bent beam. The middle is naturally laid out into a trapezoidal shape.

5. The iron-gallium magnetostrictive drive module according to claim 1, characterized in that, The main beam coil and the secondary beam coil are arranged in opposite directions. When current flows through the coil, induced magnetic fields in opposite directions are generated in the main beam and the secondary beam. The magnetic field flows from the main beam into the secondary beam at one end of the beam and from the secondary beam into the main beam at the other end, forming a closed magnetic circuit between the two beams.

6. The iron-gallium magnetostrictive drive module according to claim 1, characterized in that, The permanent magnets have opposite magnetization directions on the left and right sides.

7. The iron-gallium magnetostrictive drive module according to claim 1, characterized in that, The magnetic circuit of the iron-gallium magnetostrictive drive module is designed with separate dynamic and static magnetic circuits. The initial direction of the dynamic magnetic circuit of the main beam is the same as that of the static magnetic circuit. The magnetic field inside the main beam is superimposed and enhanced, causing the main beam to elongate. The initial direction of the dynamic magnetic circuit of the secondary beam is opposite to that of the static magnetic circuit. The magnetic field inside the secondary beam is canceled and weakened, causing the secondary beam to contract. The extension and contraction of the main and secondary beams cause the main beam to bend outward. Under the dynamic driving action of the drive coil, the main beam bends and vibrates inward and outward, inputting force and displacement to the outside.

8. The iron-gallium magnetostrictive drive module according to claim 1, characterized in that, The iron-gallium magnetostrictive drive module also includes a support frame and a prestressed pressure plate; the support frame, viewed from above, is "I" shaped, with slots on the left and right sides for inserting and fixing permanent magnets, and auxiliary support arms extending upward and downward from the two ends of the slots, with threaded holes on each support arm; A gallium iron oxide magnetostrictive drive module is equipped with two prestressed pressure plates, one on each side. The main body of the prestressed pressure plate is a square thick plate with two small square feet on the top and bottom. The gallium iron oxide bending beam is embedded to form a normal fit, which is used to position the gallium iron oxide bending beam. The prestressed pressure plate is provided with through holes for threaded holes of the support arm, which are used to insert screws for fixing. The length of the gallium iron oxide bending beam must exceed the length of the support frame. The excess part is the compression amount. Tightening the screws provides prestress to the gallium iron oxide bending beam.

9. A hydroacoustic transducer, characterized in that, The underwater acoustic transducer uses the iron-gallium magnetostrictive drive module as described in any one of claims 1-8.

10. The underwater acoustic transducer according to claim 9, characterized in that, The underwater acoustic transducer is a composite rod transducer, a bending transducer, or an inlaid ring transducer.

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