Piston type underwater acoustic transducer

Abstract

The utility model discloses a piston type underwater acoustic transducer, which comprises a piston plate, the Euler buckling beams are connected to the connecting rods of the piston plates in a surrounding mode; the other end of the Euler buckling beam is in a fixed state and is connected with a non-vibration structure of the transducer shell; the return springs are respectively arranged along the bottom of the disc above the piston plate; the rubber folding rings are annularly connected to the outer side wall of the disc above the piston plate and deform and move along with vibration of the piston plate; the other end of the rubber folding ring is in a fixed state and is connected with a non-vibration structure of the transducer shell; the driving coil is fixedly connected to the periphery of the bottom of the disc below the piston plate; a magnetic circuit air gap is formed in the magnetic circuit; wherein the driving coil is located in the magnetic circuit air gap. According to the piston type underwater acoustic transducer, nonlinearity of an electromagnetic physical field and a mechanical physical field is counteracted through nonlinear matching of the electromagnetic physical field and the mechanical physical field, so that the aim of improving the working linearity of the piston type underwater acoustic transducer is fulfilled.

Description

Technical Field

[0001] This utility model relates to a piston-type underwater acoustic transducer, specifically a piston-type underwater acoustic transducer, belonging to the technical field of underwater acoustic transducers. Background Technology

[0002] Generally speaking, ultra-low frequency underwater acoustic transducers are key devices for underwater long-range information transmission and target detection, and represent one of the important development directions for underwater acoustic transducers. Piston-type underwater acoustic transducers typically use electrical energy converted into mechanical vibration through a magnetic field to drive a piston to radiate sound waves into the water medium. They have advantages such as low resonant frequency, wide operating bandwidth, small size, and light weight, making them very suitable for use as ultra-low frequency underwater acoustic transmitting transducers.

[0003] When reciprocating underwater acoustic transducers operate at tens or even several hertz, the vibrating piston surface needs to achieve sufficiently large vibrational displacement to radiate sufficiently high acoustic energy. When the piston surface operates under large amplitude conditions, the large structural deformation and nonlinearity of the driving magnetic field become extremely prominent, leading to harmonic distortion in the ultra-low frequency acoustic radiation of the reciprocating transducer. Total harmonic distortion (THD) is a key indicator for measuring the acoustic radiation capability of underwater acoustic transducers, and the harmonic distortion problem under large-amplitude piston surface vibration significantly limits the application of reciprocating transducers in the ultra-low frequency field.

[0004] Piston-type underwater acoustic transducers are typically electromagnetically driven devices. Those skilled in the art know how to reduce harmonic distortion through modulation using magnetic field excitation. For example, Chinese utility model patent CN 112911469B discloses an electromagnetic transducer that utilizes a permanent magnet embedded in a magnetic circuit to generate a constant bias magnetic field and an alternating driving magnetic field generated by an AC coil. The two are superimposed to form an alternating magnetic field containing a DC bias, employing a hybrid excitation method to improve output harmonic distortion and performance evaluation issues under traditional frequency doubling excitation. In the same patent, CN 112911469B, an existing helical compression spring is used, whose stiffness generally exhibits linear characteristics within the operating range. This patent primarily addresses harmonic distortion from an electromagnetic field perspective.

[0005] Furthermore, since loudspeakers and reciprocating underwater acoustic transducers operate on similar principles, their methods for suppressing harmonics can also provide inspiration for the field of underwater acoustic transducers. For example, Chinese utility model patent CN 210298061 U discloses "A Moving Coil Loudspeaker That Can Improve Distortion," which relates to a moving coil loudspeaker that can improve distortion. This is achieved by placing a short-circuit ring with high conductivity and low permeability within the magnetic cavity. The short-circuit ring compensates for eddy currents, making the inductance-displacement curve symmetrical, and reducing the inductance when the voice coil moves into the magnetic circuit, thereby reducing even-order harmonic distortion. The above methods all aim to reduce distortion caused by electromagnetic field nonlinearity, addressing harmonic distortion from the electrical end. However, they do not consider the harmonic distortion caused by the large-amplitude vibration nonlinearity of the piston surface, which can lead to severe harmonic distortion due to the geometric nonlinearity of the large-amplitude vibration.

[0006] Therefore, the key to solving the above-mentioned technical problems lies in developing a piston-type underwater acoustic transducer that can reduce transducer harmonic distortion and improve the ultra-low frequency acoustic radiation capability of the piston-type underwater acoustic transducer by taking into account both electromagnetic nonlinearity and geometric nonlinearity. Utility Model Content

[0007] In view of the many defects and shortcomings of the above-mentioned background technology, this utility model has made improvements and innovations, aiming to provide a piston-type underwater acoustic transducer solution. It abandons the traditional design method of suppressing nonlinearity from a single physical field or a single subsystem, and ingeniously "cancels off" the nonlinearity of the electromagnetic physical field and the mechanical physical field by matching the nonlinearity of the two, thereby achieving the goal of improving the working linearity of the piston-type underwater acoustic transducer.

[0008] Another utility model objective is to develop a piston-type underwater acoustic transducer with significant advantages such as low harmonic content, low distortion, strong resistance to hydrostatic pressure, and high ultra-low frequency radiated acoustic power, so that it can be used as a general underwater sound source or as an effective acoustic load mounted on an underwater vehicle or towed body.

[0009] To solve the above problems and achieve the above-mentioned utility model objectives, this utility model provides a piston-type underwater acoustic transducer through the following design structure and the following technical solution:

[0010] A piston-type underwater acoustic transducer includes:

[0011] Piston plate (1);

[0012] Euler buckling beam (2) is respectively enclosed on the connecting rod of piston plate (1) and deforms and moves with the vibration of piston plate (1); the other end of Euler buckling beam (2) is fixed and connected to the non-vibrating structure of transducer shell, and there is no displacement change at the fixed point during operation;

[0013] Return spring (3), the return spring (3) is set along the bottom of the upper disk of the piston plate (1);

[0014] Rubber folding ring (4) is connected circumferentially to the outer wall of the disk above the piston plate (1), and deforms and moves with the vibration of the piston plate (1); the other end of the rubber folding ring (4) is fixed and connected to the non-vibrating structure of the transducer housing, and there is no displacement change at the fixed point during operation.

[0015] Drive coil (5) is fixedly connected to the bottom outer periphery of the disc below the piston plate (1);

[0016] Magnetic circuit (6), and a magnetic circuit air gap (61) is opened in the magnetic circuit (6);

[0017] The driving coil (5) is located in the air gap (61) of the magnetic circuit, and the two do not come into contact.

[0018] Preferably, the piston plate (1) includes an upper disk and a lower disk, and a connecting rod connected at the center between the upper disk and the lower disk, wherein the diameter of the upper disk is larger than the diameter of the lower disk.

[0019] Preferably, the axis of symmetry of the Euler buckling beam (2) forms a certain angle θ with the upper disk surface of the piston plate (1), and the range of the angle θ is 0°<θ≤30°, which is used to control the range of negative stiffness by the size of the angle θ.

[0020] Preferably, the Euler buckling beam (2) is a multi-layered thin-sheet stacked structure.

[0021] Preferably, the return spring (3) is composed of multiple spring units connected in parallel.

[0022] Preferably, the spring unit is a compression coil spring or a leaf spring.

[0023] Preferably, the rubber fold (4) is made of a corrosion-resistant and aging-resistant rubber material.

[0024] Preferably, the drive coil (5) is a single coil or multiple coils, and is wound with copper core enameled wire, aluminum core enameled wire or copper-clad aluminum enameled wire.

[0025] Preferably, the magnetic circuit (6) is composed of a permanent magnet and a magnetically conductive material to provide a static magnetic field;

[0026] Or the magnetic circuit (6) is composed of an excitation coil and a magnetic material to form an excitation magnetic circuit, which is used to provide a static or dynamic magnetic field;

[0027] Alternatively, the magnetic circuit (6) consists of an excitation coil, a permanent magnet and a magnetic conductive material, forming a permanent magnet-excitation composite magnetic circuit, which is used to provide a static or dynamic magnetic field.

[0028] Preferably, the magnetic circuit air gap (61) is formed in an inner circumferential direction inward along the outer periphery of the top of the magnetic circuit (6), wherein the middle cross-section of the magnetic circuit (6) is in an inverted "convex" shape.

[0029] The working principle is as follows: During operation, the magnetic circuit (6) provides a stable magnetic field in the magnetic circuit air gap (61) of the transducer. After the driving coil (5) is loaded with a changing current signal, under the action of the magnetic field, it is subjected to a driving force that changes in magnitude and direction along the normal direction of the piston surface (x-axis direction). Under the combined action of the restoring force-damping provided by the Euler buckling beam (2), the restoring spring (3) and the rubber surround (4), the piston plate (1) is driven to reciprocate and vibrate to radiate sound waves into the external water medium. Existing methods for reducing the harmonic distortion of underwater acoustic transducers usually start from the root cause of harmonic generation and perform non-linear suppression from a single physical field or a single subsystem. For example, if non-linearity is generated electromagnetically, then starting from the electromagnetic physical field, the distortion of the electromagnetic field is reduced; if non-linearity is generated in the structure, then starting from the mechanical physical field, the non-linearity of the structure is reduced. A piston-type underwater acoustic transducer of the present utility model can systematically consider the coupling of the electromagnetic physical field and the mechanical physical field, and through the non-linear matching of the electromagnetic physical field and the mechanical physical field, use the non-linearity of the two to "cancel each other out", so as to reduce the harmonic distortion problem of the entire system of the transducer, thereby achieving the purpose of improving the working linearity of the piston-type underwater acoustic transducer.

[0030] The beneficial effects of the present utility model compared with the prior art are as follows:

[0031] 1. A piston-type underwater acoustic transducer solution of the present utility model abandons the method of non-linear suppression from a single physical field or a single subsystem in the traditional design, and奇妙地通过电磁物理场与力学物理场的非线性匹配,将二者的非线性进行“抵消”,从而实现改善活塞式水声换能器工作线性度的目的;(The description here seems a bit unclear in the original Chinese. It might be better to rephrase it for a more accurate translation. For now, I'll try to keep it as close as possible.) By奇妙地通过电磁物理场与力学物理场的非线性匹配,将二者的非线性进行“抵消”,从而实现改善活塞式水声换能器工作线性度的目的;(This part seems to have some redundant or unclear表述. Maybe it should be something like "wonderfully through the non-linear matching of the electromagnetic physical field and the mechanical physical field, cancel the non-linearity of the two, so as to achieve the purpose of improving the working linearity of the piston-type underwater acoustic transducer") Specifically, it cancels the non-linearity of the two through the non-linear matching of the electromagnetic physical field and the mechanical physical field, thereby achieving the purpose of improving the working linearity of the piston-type underwater acoustic transducer;

[0032] 2. The piston-type underwater acoustic transducer of the present utility model has the remarkable advantages of having few harmonic components, low distortion, strong hydrostatic pressure resistance, and high ultra-low frequency radiation sound power, and can be used as an underwater general sound source or as an effective acoustic payload carried on an underwater vehicle or a towed body;

[0033] 3. The Euler buckling beam of the present utility model itself has a "negative stiffness" characteristic. By selecting a restoring spring with a "positive stiffness" characteristic, after the parallel combination of the Euler buckling beam and the restoring spring with "positive and negative stiffness" characteristics, they jointly form an elastic system with "high static stiffness and low dynamic stiffness", providing a stiffness curve with specific characteristics (including a stiffness curve that can provide a similar "bathtub curve") for the transducer, which can be used to cancel the non-linearity of the couple factor caused by the magnetic circuit non-linearity;

[0034] 4. This utility model can also be designed with an offset design to form a specific angle between the axis of symmetry of the Euler buckling beam and the piston surface, and the range of negative stiffness can be controlled by the size of the angle, thereby adjusting the stiffness characteristic curve;

[0035] 5. The Euler buckling beam in this utility model will buckle after large deformation and has the mechanical property of negative stiffness, while the restoring spring has the property of linear stiffness. When the two are combined, they have specific stiffness characteristics and can have "high static stiffness and low dynamic stiffness characteristics", thus realizing the "active introduction" of nonlinear stiffness in the piston-type underwater acoustic transducer.

[0036] 6. This utility model can also design a specific stiffness characteristic curve by adjusting the stiffness ratio of the Euler buckling beam to the restoring spring. Attached Figure Description

[0037] The specific embodiments of this utility model will be further described in detail below with reference to the accompanying drawings, wherein:

[0038] Figure 1 This is one of the overall structural schematic diagrams of this utility model;

[0039] Figure 2 This is the second schematic diagram of the overall structure of this utility model;

[0040] Figure 3 This is a schematic diagram of the nonlinear curve of the couple factor provided in this embodiment of the utility model;

[0041] Figure 4 This is a schematic diagram of the nonlinear curve of structural stiffness provided in an embodiment of this utility model;

[0042] Figure 5 This is a schematic diagram showing that the structural stiffness and couple factor of an existing piston transducer are nonlinear.

[0043] Figure 6 This is a schematic diagram showing that the structural stiffness and couple factor cancel each other out linearly, as provided in this embodiment of the utility model.

[0044] In the figure, the numbers are: 1—piston plate, 2—Euler buckling beam, 3—returning spring, 4—rubber folding ring, 5—drive coil, 6—magnetic circuit, 61—magnetic circuit air gap. Detailed Implementation

[0045] To make the technical means, inventive features, objectives, and effects of this utility model readily understandable, the technical solution of this utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other. The present utility model will now be described in detail with reference to the accompanying drawings and embodiments.

[0046] like Figures 1 to 6 The piston-type underwater acoustic transducer shown includes:

[0047] Piston plate 1, the cross-section of piston plate 1 is in the shape of an "I" with a wider top and a narrower bottom;

[0048] Euler buckling beam 2 is respectively enclosed on the connecting rod of piston plate 1. It deforms and moves with the vibration of piston plate 1. The other end of Euler buckling beam 2 is fixed. It is connected to the non-vibrating structure of transducer shell. There is no displacement change at the fixed point during operation.

[0049] Returning spring 3 is set at equal intervals along the bottom of the upper disk of piston plate 1;

[0050] Rubber folding ring 4 is circumferentially connected to the outer wall of the disk above the piston plate 1. It deforms and moves with the vibration of the piston plate 1. The other end of the rubber folding ring 4 is fixed. It is connected to the non-vibrating structure of the transducer housing. There is no displacement change at the fixed point during operation.

[0051] Drive coil 5 is fixedly connected to the outer periphery of the bottom of the disc below piston plate 1;

[0052] Magnetic circuit 6, with a magnetic air gap 61 inside the magnetic circuit 6;

[0053] The drive coil 5 is located in the air gap 61 of the magnetic circuit, and the two do not come into contact.

[0054] Furthermore, the piston plate 1 is used as a mechanical-to-acoustic energy conversion structure, utilizing longitudinal vibration modes to transmit the ability to the external water medium through vibration and radiate sound waves. The piston plate 1 includes an upper disk and a lower disk, as well as a connecting rod connected at the center between the upper disk and the lower disk. The diameter of the upper disk is larger than the diameter of the lower disk.

[0055] Furthermore, the piston plate 1 is made of lightweight and high-strength non-metallic materials, or of corrosion-resistant metals, or of metals with a surface coating of anti-corrosion coating.

[0056] Furthermore, the axis of symmetry of the Euler buckling beam 2 forms a certain angle θ with the upper disk surface of the piston plate 1. The range of the angle θ is 0° < θ ≤ 30°, and the range of negative stiffness can be controlled by the size of the angle θ.

[0057] Furthermore, the Euler buckling beam 2 is made of a highly elastic metal material, namely beryllium bronze, wherein the Euler buckling beam 2 is a multi-layered thin-sheet stacked structure.

[0058] In this invention, the Euler buckling beam 2 itself exhibits "negative stiffness" characteristics.

[0059] Furthermore, the return spring 3 is used to provide restoring force for the piston plate 1 during reciprocating vibration. The return spring 3 is made of non-magnetic material or demagnetized material.

[0060] Furthermore, the return spring 3 is composed of multiple spring units connected in parallel. The spring units are compression helical springs or leaf springs, wherein both compression helical springs and leaf springs have linear characteristics.

[0061] In this invention, since there is more or less magnetic leakage in the magnetic circuit 61, the material of the return spring 3 is preferably a non-magnetic material or a demagnetized material; the return spring 3 is composed of multiple sets of linear compression helical spring units connected in parallel and evenly arranged along the bottom of the upper disk of the piston plate 1.

[0062] Furthermore, the rubber fold 4 is made of corrosion-resistant and aging-resistant rubber material. The rubber fold 4 serves as an underwater seal and provides damping, making the transducer's transmission response curve flatter and improving the transducer's broadband transmission capability.

[0063] In this invention, the rubber fold ring 4 has an overall "Ω" shaped structure. Since the rubber fold ring is in long-term contact with the external water medium, the rubber fold ring 4 is made of a corrosion-resistant and anti-aging rubber material. Preferably, in this embodiment of the invention, the rubber fold ring 4 is prepared by a process of woven fiber skeleton compounding silicone rubber, which can make the transducer's transmission response curve flatter and improve the transducer's broadband transmission capability.

[0064] Furthermore, the drive coil 5 is a single coil or multiple coils, and is wound with copper core enameled wire, aluminum core enameled wire or copper-clad aluminum enameled wire.

[0065] Furthermore, the magnetic circuit 6 is used to provide a magnetic field for the underwater acoustic transducer. The magnetic circuit 6 is composed of a permanent magnet and a magnetically conductive material to form a permanent magnet circuit, which is used to provide a static magnetic field.

[0066] Alternatively, magnetic circuit 6 may consist of an excitation coil and a magnetic material forming an excitation magnetic circuit, used to provide a static or dynamic magnetic field;

[0067] Alternatively, magnetic circuit 6 consists of an excitation coil, a permanent magnet, and a magnetically conductive material, forming a permanent magnet-excitation composite magnetic circuit used to provide static or dynamic magnetic fields.

[0068] In this invention, the magnetic flux density of the magnetic field is represented by B. In this embodiment, the magnetic circuit 6 is a permanent magnet circuit composed of a permanent magnet and a magnetically conductive material, which is used to provide a static magnetic field. After the drive coil 5 is energized, it becomes an energized solenoid, which works in accordance with the law of electromagnetic induction and is used to drive the vibration of the piston plate 1.

[0069] Further, the magnetic circuit air gap 61 is circumferentially opened inward along the outer periphery of the top of the magnetic circuit 6, and the upper opening diameter of the magnetic circuit air gap 61 is larger than the lower opening diameter. Among them, the middle cross-section of the magnetic circuit 6 is in an inverted "convex" shape.

[0070] In the present utility model, the magnetic circuit 6 is fixedly installed and coaxially arranged with the driving coil 5. The driving coil 5 is located in the gap of the magnetic circuit air gap 61, and the two do not come into contact.

[0071] To sum up, a more specific implementation manner of the present utility model is as follows:

[0072] During operation, the magnetic circuit 6 provides a stable magnetic field in the magnetic circuit air gap 61 of the transducer. After the driving coil 5 is loaded with a changing current signal, under the action of the magnetic field, it is subjected to a driving force that changes in magnitude and direction along the normal x-axis direction of the piston surface. Under the combined action of the restoring force-damping provided by the Euler buckling beam 2, the return spring 3, and the rubber corrugated ring 4, the driving piston plate 1 reciprocates to vibrate and radiate sound waves into the external water medium. The existing methods to reduce the harmonic distortion of underwater acoustic transducers usually start from the root cause of harmonic generation and perform non-linear suppression from a single physical field or a single subsystem. For example, if the non-linearity is generated by electromagnetics, then starting from the electromagnetic physical field, the distortion of the electromagnetic field is reduced; if the non-linearity is generated by the structure, then starting from the mechanical physical field, the non-linearity of the structure is reduced. A piston-type underwater acoustic transducer of the present utility model can systematically consider the coupling of the electromagnetic physical field and the mechanical physical field. Through the non-linear matching of the electromagnetic physical field and the mechanical physical field, and using the non-linearity of the two to "cancel each other out", the harmonic distortion problem of the entire system of the transducer is reduced, thereby achieving the purpose of improving the working linearity of the piston-type underwater acoustic transducer.

[0073] In the present utility model, the piston plate 1 is used as an energy conversion structure from mechanics to acoustics, and uses the longitudinal vibration mode to transfer energy to the external water medium through vibration and radiate sound waves.

[0074] In the present utility model, the Euler buckling beam 2 itself has a "negative stiffness" characteristic, and a return spring 3 with a "positive stiffness" characteristic is selected. After the parallel combination of the Euler buckling beam 2 and the return spring 3 with "positive and negative stiffness" characteristics, they jointly form an elastic system with "high static stiffness and low dynamic stiffness", providing a stiffness curve with specific characteristics for the transducer as shown in the appendix. Figure 4 The symmetry axis of the Euler buckling beam 2 forms a certain angle with the piston surface, and the interval of the negative stiffness can be controlled by the size of the angle.

[0075] In the present utility model, the return spring 3 is used to provide a restoring force during the reciprocating vibration of the piston plate 1. In the example of the present utility model, a compression helical spring with linear characteristics is selected.

[0076] In this invention, the rubber folding ring 4 serves as an underwater seal and provides damping. In this example, the transducer is prepared using a process of weaving fiber skeleton and mixing silicone rubber, which can make the transducer's transmission response curve flatter and improve the transducer's broadband transmission capability.

[0077] In this invention, the drive coil 5 is a single coil or multiple coils, wound with copper core enameled wire, aluminum core enameled wire, or copper-clad aluminum enameled wire. When energized, the drive coil 5 is called a solenoid, and its operation follows the law of electromagnetic induction. The total length of the coil is represented by L. When energized, the drive coil 5 experiences a Lorentz force in the magnetic circuit; the product of the magnetic flux density and the coil is called the couple factor, denoted by BL. The curve showing the change of the couple factor along the direction of vibration displacement is denoted by BLx, as shown in the attached figure. Figure 3 As shown, during the reciprocating motion of the drive coil 5 along the piston surface normal of the piston plate 1, the magnetic field lines generated by the magnetic circuit pass through the drive coil 5 and change with the vibration displacement. Therefore, the couple factor exhibits nonlinearity and usually has the characteristics of an "inverted bathtub curve".

[0078] In this invention, the magnetic circuit 6 provides a magnetic field for the underwater acoustic transducer. In this embodiment, a permanent magnet circuit composed of a permanent magnet and a magnetically conductive material is used to provide a static magnetic field. The drive coil 5, when energized, becomes a solenoid, operating according to the law of electromagnetic induction, and is used to drive the vibration of the piston plate 1.

[0079] The magnetic circuit 6 provides a stable magnetic field in the air gap 61 of the transducer. After the driving coil 5 is loaded with a changing current signal, it is subjected to a driving force with varying magnitude and direction along the normal x-axis of the piston surface under the action of the magnetic field. Under the combined action of the restoring force-damping provided by the Euler buckling beam 2, the restoring spring 3 and the rubber folding ring 4, the piston plate 1 is driven to reciprocate and radiate sound waves into the external water medium.

[0080] The specific steps for using it are:

[0081] As attached Figure 4 As shown, the Euler buckling beam 2 buckles after large deformation, exhibiting negative stiffness mechanical properties, while the restoring spring 3 possesses linear stiffness characteristics. Combining these two components replaces the linear restoring spring in existing piston-type hydroacoustic transducers. Adjusting the stiffness ratio of the Euler buckling beam 2 to the restoring spring 3 results in an overall stiffness curve resembling a "bathtub curve." (See attached diagram.) Figure 4 As shown, the stiffness curve is represented by Kx. Therefore, the piston-type underwater acoustic transducer possesses the nonlinear characteristics of "high static stiffness and low dynamic stiffness". During operation, the Euler buckling beam 2 is subjected to cyclic loads for extended periods. In this embodiment, a highly elastic metallic material—beryllium bronze—is selected, and a multi-layered thin-sheet stacked structure is employed to further improve the fatigue resistance of the Euler buckling beam.

[0082] Existing methods for reducing harmonic distortion in underwater acoustic transducers typically start from the source of harmonic generation, suppressing nonlinearity from a single physical field or a specific subsystem. For example, if electromagnetic nonlinearity is generated, the focus is on reducing the distortion of the electromagnetic field; if structural nonlinearity is generated, the focus is on reducing the nonlinearity of the structure from the mechanical field.

[0083] The present invention provides a piston-type underwater acoustic transducer, the core of which is to systematically consider the coupling of electromagnetic physical fields and mechanical physical fields, and to "cancel" the nonlinearity of the electromagnetic physical field and mechanical physical field by nonlinear matching of the two, thereby reducing the harmonic distortion problem of the entire transducer system and thus improving the working linearity of the piston-type underwater acoustic transducer.

[0084] The core technical feature of this transducer is that the Euler buckling beam and the restoring spring can form a "high static stiffness and low dynamic stiffness system", providing the transducer with a stiffness curve with specific characteristics, including a stiffness curve similar to a "bathtub curve", which can be used to offset the nonlinearity of the couple factor caused by the nonlinearity of the magnetic circuit, and can also be biased to design the Euler beam symmetry axis to form a specific angle with the piston surface, and the range of negative stiffness can be controlled by the size of the angle.

[0085] To further illustrate the beneficial effects of the piston-type underwater acoustic transducer proposed in this utility model, existing piston-type transducers and the solutions proposed in the embodiments of this utility model are presented respectively.

[0086] As attached Figure 5 As shown, the two curves on the left are the structural stiffness curve and the coupling factor curve of an existing piston transducer, respectively. The structural stiffness exhibits a linear characteristic, denoted by KLx, while the coupling factor exhibits a nonlinear characteristic, denoted by BLx. When the two are superimposed, the overall characteristic remains nonlinear.

[0087] As attached Figure 6 As shown, the two curves on the left are the structural stiffness curve and the coupling factor curve of this utility model, respectively. Among them, the coupling factor exhibits nonlinear characteristics and is represented by BLx. After matching the coupling factor with the transducer structure, the overall stiffness of the transducer structure, which combines the Euler buckling beam 2 and the restoring spring 3, exhibits nonlinear characteristics and is represented by Kx. After superimposing the two, the transducer as a whole exhibits obvious linear characteristics.

[0088] In the description of this specification, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0089] In the entire implementation process described above, piston plate 1 is used to realize the conversion of force and sound energy. The transducer uses the reciprocating vibration of the piston plate to convert vibration energy into sound waves, which are then propagated to the outside through the interface between piston plate 1 and the water medium. Euler buckling beam 2 buckles after large deformation and has the mechanical characteristic of negative stiffness, which is used to provide negative stiffness for the transducer. Return spring 3 has linear positive stiffness characteristics. By combining Euler buckling beam 2 and return spring 3 in a specific way, the transducer can have the characteristics of high static stiffness and low dynamic stiffness. Rubber folding ring 4 is used to provide a reliable seal for the transducer to reciprocate underwater and to add a certain amount of damping to the transducer, improve vibration characteristics, and increase the transducer's working bandwidth. Drive coil 5 is used to provide power for the movement of piston plate 1. Utilizing the principle that the current-carrying coil receives the Lorentz force in the magnetic circuit, the magnitude and direction of the current in the drive coil are changed to realize the reciprocating vibration of the piston plate 1. Magnetic circuit 6 is used to generate a stable magnetic field to realize the electro-magnetic interaction with drive coil 5. Magnetic circuit air gap 61 is used to provide movement space for drive coil 5.

[0090] Finally, it should be noted that the specific embodiments described above are merely illustrative or explanatory of the principles of this utility model and do not constitute a limitation thereof. Therefore, any modifications, equivalent substitutions, or improvements made without departing from the spirit and scope of this utility model should be included within its protection scope. Furthermore, the appended claims are intended to cover all variations and modifications falling within the scope and boundaries of the appended claims, or equivalent forms of such scope and boundaries.

Claims

1. A piston-type underwater acoustic transducer, characterized in that, Comprising: Piston plate (1); Euler buckling beam (2), the Euler buckling beam (2) is respectively arranged around and connected to the connecting rod of the piston plate (1), and deforms and moves along with the vibration of the piston plate (1); the other end of the Euler buckling beam (2) is in a fixed state and is connected to the non-vibrating structure of the transducer housing, and there is no displacement change at the fixed point during operation; Return spring (3), the return spring (3) is respectively arranged along the bottom of the upper disc of the piston plate (1); Rubber surround (4), the rubber surround (4) is respectively connected circumferentially to the outer side wall of the upper disc of the piston plate (1), and deforms and moves along with the vibration of the piston plate (1); the other end of the rubber surround (4) is in a fixed state and is connected to the non-vibrating structure of the transducer housing, and there is no displacement change at the fixed point during operation; Drive coil (5), the drive coil (5) is fixedly connected to the outer periphery of the bottom of the lower disc of the piston plate (1); Magnetic circuit (6), a magnetic circuit air gap (61) is provided in the magnetic circuit (6); Wherein, the drive coil (5) is located in the magnetic circuit air gap (61), and the two do not come into contact.

2. The piston-type underwater acoustic transducer according to claim 1, characterized in that, The piston plate (1) includes an upper disc, a lower disc and a connecting rod connected to the central position between the upper disc and the lower disc, and the diameter of the upper disc is larger than that of the lower disc.

3. A piston-type underwater acoustic transducer according to claim 1, characterized in that, The symmetry axis of the Euler buckling beam (2) forms a certain angle θ with the upper disc surface of the piston plate (1), and the range of the angle θ is 0° < θ ≤ 30°, which is used to control the negative stiffness interval by the size of the angle θ.

4. A piston-type underwater acoustic transducer according to claim 1 or 3, characterized in that, The Euler buckling beam (2) is a multi-layer thin sheet stacked structure.

5. A piston-type underwater acoustic transducer according to claim 1, characterized in that, The return spring (3) is composed of multiple spring units connected in parallel.

6. A piston-type underwater acoustic transducer according to claim 5, characterized in that, The spring unit is a compression helical spring or a plate spring.

7. A piston-type underwater acoustic transducer according to claim 1, characterized in that, The rubber surround (4) is made of a rubber material that is corrosion-resistant and anti-aging.

8. A piston-type underwater acoustic transducer according to claim 1, characterized in that, The drive coil (5) is a single coil or a multi-coil, and is wound with copper core enameled wire, aluminum core enameled wire or copper-clad aluminum enameled wire.

9. A piston-type underwater acoustic transducer according to claim 1, characterized in that, The magnetic circuit (6) consists of a permanent magnet and a magnetic conductive material to form a permanent magnetic circuit for providing a static magnetic field; Or the magnetic circuit (6) consists of an excitation coil and a magnetic conductive material to form an excitation magnetic circuit for providing a static or dynamic magnetic field; Or the magnetic circuit (6) consists of an excitation coil, a permanent magnet and a magnetic conductive material to form a permanent-excitation composite magnetic circuit for providing a static or dynamic magnetic field.

10. A piston-type underwater acoustic transducer according to claim 1, characterized in that, The magnetic circuit air gap (61) is circumferentially opened inward along the outer periphery of the top of the magnetic circuit (6), wherein the middle cross-section of the magnetic circuit (6) is in an inverted "convex" shape.

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