An underwater very low frequency sound source based on a moving coil drive mechanism

Abstract

The present invention relates to the field of very low frequency sound sources, and in particular to an underwater very low frequency sound source based on a moving coil drive mechanism. The main components of the underwater very low frequency sound source of the present invention include a very low frequency transmitting module and a pressure compensation module. In the very low frequency transmitting module, the radiation surface adopts a flat aluminum plate design; a large-size and high-efficiency magnetic circuit is adopted, and a composite material is used as the dynamic cylinder skeleton. The structural strength is not affected, and it is resistant to high temperature and light in weight; the driving coil is made of two groups of coils wound up and down respectively, and connected in parallel, so that the impedance of the sound source is small. The pressure compensation module currently usually adopts air bags or leather bags of different volumes to realize the pressure compensation function. The design volume of the air bag determines the limit of the working depth of the underwater very low frequency sound source. The current maximum working depth is 100m. The structural design of the underwater very low frequency sound source pressure compensation module can also be determined according to the user's different needs for the sound source size, usage or working depth.

Description

Technical Field

[0001] The invention relates to the field of very low frequency sound sources, and in particular to an underwater very low frequency sound source realized based on a moving coil driving mechanism. Background Art

[0002] With the development of underwater acoustic engineering and the importance of the ocean to human survival, very low frequency sound waves with the advantage of propagation distance have very important application value in the fields of ocean research, resource development, military, etc. Very low frequency (VLF) refers to the frequency band below 1000Hz.

[0003] In the field of ocean research, low-frequency broadband sound sources are indispensable research tools. Using low-frequency broadband sound sources to emit sound waves, the ocean acoustic tomography technology can be used to observe the temperature field and velocity field of seawater in a vast sea area, and obtain images of the dynamic changes in the sea area. Low-frequency broadband sound sources can also be used for ocean acoustic temperature measurement. By emitting a low-frequency broadband sound source that can be transmitted over long distances to measure the average value of the sound velocity change on the sound propagation path, the average seawater temperature on the propagation path is obtained, and the changes in the earth's atmospheric circulation are calculated based on the temperature rise of the seawater.

[0004] In the field of traditional military applications, low-frequency broadband transmitting sound sources have unique application prospects. In terms of submarine communications, due to the advantage of long propagation distance of low-frequency broadband transmitting sound sources, they are very suitable as a carrier for information exchange with submarines; in anti-mine warfare, advanced acoustic minesweeping equipment with acoustic minesweeping function is indispensable for clearing advanced mines. Low-frequency broadband transmitting sound sources are the most important component of acoustic minesweeping, which is used to simulate the "soundprint" of ships; in the application of passive sonar operator training, sonar training simulators use sound source combinations containing low-frequency broadband transmitting sound sources and capable of full-band transmission at different depths to simulate the signals emitted by various submarines. The purpose of training operators is achieved through actual judgment by sonar operators. The most notable feature of sonar training simulators is that the training cost-effectiveness is high and close to actual combat needs. As one of the core equipment, low-frequency broadband transmitting sound sources play a pivotal role in it. In the application of audio test systems, a broadband calibration system with low-frequency broadband transmission capability is required to calibrate the hydrophone, ensuring the accuracy and reliability of the performance indicators of the hydrophone, the core component of passive sonar, after production.

[0005] With the further development of low-frequency broadband transmitting sound source technology, its technical applications have been further expanded. In anti-hydroacoustic detection operations, it can increase the regional marine environmental noise and provide cover for submarine travel; low-frequency broadband transmitting sound sources can also be used as regional protection equipment to prevent attacks from small targets such as frogmen.

[0006] 1. Overseas research

[0007] The same type of low-frequency broadband transmitting sound source is the UW series electric very low frequency sound source launched by Data Physics of the United States, including two models: UW350 and UW600. The operating frequency band of the UW350 electric very low frequency sound source is 20Hz~20kHz, the maximum sound source level is 165dB, and the maximum working depth is 188 meters; the operating frequency band of the UW600 electric very low frequency sound source is 4Hz~900Hz, the maximum sound source level is 185dB, and the maximum working depth is 200 meters.

[0008] 2. Domestic research situation

[0009] In the development of electric very low frequency sound sources, China has relatively mature electric very low frequency sound sources with an operating frequency range of 10Hz to 2kHz, a maximum average sound source level of ≥160dB, and a maximum operating depth of 300m. Summary of the invention

[0010] The purpose of the present invention is to solve the problems existing in the prior art and to provide an underwater very low frequency sound source based on a moving coil drive mechanism.

[0011] To achieve the above object, the present invention is implemented through the following technical solutions.

[0012] The present invention proposes an underwater very low frequency sound source based on a moving coil drive mechanism, wherein the sound source comprises a very low frequency transmitting module; the very low frequency transmitting module comprises: a hollow cylindrical shell with openings on both sides, a magnetic conductive structure, a magnet, a moving coil linear driving structure, and a radiation surface structure formed by a metal plane plate and installed on an opening surface of the shell;

[0013] The magnetic conductive structure is a hollow cylinder matching the interior of the outer shell cylinder, and both the upper and lower surfaces of the hollow cylinder are provided with magnetic gaps in the shape of an annular cylinder;

[0014] The magnet is placed at the center of the magnetic conductive structure to form an air cavity in the shape of a ring column with the magnetic conductive structure;

[0015] The moving coil linear drive structure comprises: an annular cylindrical coil frame, a coil winding and an elastic structure;

[0016] The coil frame is made of non-magnetic conductive material, fixedly connected to the radiation surface structure as a whole, and is used to drive the radiation surface structure to vibrate through the magnetic gap and air cavity in the shape of an annular column;

[0017] The coil winding is formed by winding the coil skeleton with two sets of upper and lower coils respectively, and the two sets of coils are connected in parallel and are respectively located at the magnetic gap of the magnetic conductive structure;

[0018] The elastic structure adopts multiple groups of springs arranged in parallel and placed between the coil frame and the radiation surface structure to control the vibration of the coil frame.

[0019] As one of the improvements of the above technical solution, the material of the magnetic conductive structure is pure iron; the material of the magnet is a permanent magnet made of neodymium iron boron.

[0020] As one of the improvements of the above technical solution, the coil skeleton and the radiation surface structure are fixedly connected as one body by screws.

[0021] As one of the improvements of the above technical solution, the elastic structure includes: a plurality of springs, a plurality of guide pillars and a spring support plate;

[0022] The spring support plate is provided with a plurality of openings; the spring support plate is fixed to an inner wall of a circle of the coil frame;

[0023] Each guide post passes through an opening on the spring support plate and is fixed on the surface of the magnetic conductive structure;

[0024] Each spring is mounted on a guide post to adjust the vibration of the coil frame.

[0025] As one of the improvements of the above technical solution, the guide pillar is straight or T-shaped;

[0026] When the guide post is in a straight line, the spring is installed between the spring support plate and the magnetic conductive structure;

[0027] When the guide post is T-shaped, the spring is installed between the top of the T-shaped guide post and the spring support plate.

[0028] As one of the improvements of the above technical solution, the upper and lower groups of coils of the coil winding are respectively connected with lead wires.

[0029] As one of the improvements of the above technical solution, the other open surface of the shell is equipped with a mounting base for mounting and fixing the magnetic conductive structure; the center of the mounting base, the centers of the two surfaces of the magnetic conductive structure and the center of the magnet are all opened to form a gas channel.

[0030] As one of the improvements of the above technical solution, the bottom of the mounting base is provided with an annular groove in the shape of an annular cylinder, which is used to provide a vibration space for the coil skeleton.

[0031] As one of the improvements of the above technical solution, the very low frequency transmission module also includes a connecting plate; a vent connected to the gas channel is opened on the connecting plate.

[0032] As one of the improvements of the above technical solution, the sound source also includes a pressure compensation module; the pressure compensation module includes an airbag protection outer tube and an airbag; the airbag is connected to the very low frequency transmission module through a vent to achieve pressure compensation; the top of the magnetic conductive structure is provided with an air replenishment port to replenish air for the airbag of the pressure compensation module. Compared with the prior art, the advantages of the present invention are:

[0033] 1. The radiation surface is designed and formed by a flat aluminum plate;

[0034] 2. Composite materials are used as the frame of the moving cylinder, which is high temperature resistant and light in weight without affecting the structural strength;

[0035] 3. The driving coil is made of two sets of coils wound up and down respectively and connected in parallel, so that the impedance of the sound source is small, which is easy to match the existing mature power amplifier, making the design volume and weight of the driving amplifier of the sound source very small;

[0036] 4. The spring structure adopts a structure in which multiple groups of springs are evenly arranged in parallel to improve the stability of the axial operation of the radiation surface;

[0037] 5. In order to increase the magnetic flux density in the air gap magnetic field of the magnetic circuit, permanent magnets made of large diameter, large size, high performance NdFeB materials are used. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a diagram of the structure of underwater very low frequency sound source;

[0039] Figure 2 It is the design drawing of the sound source radiation surface;

[0040] Figure 3 It is a schematic diagram of the radiation surface structure and the coil frame being fixed together by screws.

[0041] Figure ID

[0042] 1. Radiating surface structure 2. Spring 3. Lead wire 4. Air supply port

[0043] 5. Magnet 6. Coil frame 7. Coil winding 8. Magnetic structure

[0044] 9. Shell 10. Vent 11. Airbag 12. Airbag protection outer tube

[0045] 13. Mounting base 14. Guide column 15. Spring support plate 16. Elastic structure

[0046] 17. Connecting plate DETAILED DESCRIPTION

[0047] The technical solution of the present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0048] The main components of the new underwater VLF sound source based on the dynamic drive mechanism are the VLF transmitting module and the pressure compensation module. Figure 1 The figure shows the structure of an underwater very low frequency sound source, including a very low frequency transmitting module and a pressure compensation module. The radiation surface panel 1 is formed by processing a flat plate, and is fixedly connected to the coil skeleton 6 by screws; the elastic component is a compression spring 2, which is installed on the guide column 14. By installing the same number of springs on the upper and lower parts, the coil winding position of the coil skeleton 6 is located at the magnetic gap; the lead wire 3 is the output line of the upper and lower coils of the coil winding; the air supply port 4 is the airbag air supply port of the pressure compensation module; the magnet 5 is a customized neodymium iron boron magnet; the coil skeleton 6 is connected to the radiation surface panel, and two copper wire windings are wound on the skeleton; the coil winding 7; the magnetic conductive structure 8 is pure iron, specifically DT4 electrical pure iron; The shell 9 is a structure for fixing the electromagnetic pure iron structure; the vent 10 is the vent of the very low frequency transmitting module and the pressure compensation module; the very low frequency transmitting module is the core module, including the radiation surface, the dynamic linear drive structure, etc.; the pressure compensation module currently usually uses air bags or leather bags of different volumes to realize the pressure compensation function. The design volume of the air bag determines the limit of the working depth of the underwater very low frequency sound source. The current maximum working depth is 100m. The structural design of the underwater very low frequency sound source pressure compensation module can also be determined according to the different needs of the user for the sound source size, usage mode or working depth. The other opening surface of the shell 9 is equipped with a mounting base 13 for mounting and fixing the magnetic conductive structure 8; the center of the mounting base 13, the center of the two surfaces of the magnetic conductive structure 8 and the central opening of the magnet 5 form a gas channel. The bottom of the mounting base 13 is provided with an annular groove in the shape of an annular column, which is used to provide a vibration space for the coil skeleton 6. The very low frequency transmitting module also includes a connecting plate 17; the connecting plate 17 is provided with a vent 10 connected to the gas channel. The pressure compensation module includes an airbag protection outer tube 12 and an airbag 11; the airbag 11 is connected to the very low frequency transmission module through a vent 10 to achieve pressure compensation; the top of the magnetic conductive structure 8 is provided with an air replenishment port 4 for replenishing air to the airbag of the pressure compensation module. Specifically,

[0049] 1. The radiation surface is designed and formed by a flat plate;

[0050] In view of the connection requirements between the radiation surface and the coil frame, the radiation surface structure adopts a flat plate structure. After the flat plate is processed and formed, a vulcanization mold is designed at the same time. After the flat plate structure and the vulcanization mold are installed as one, the radiation surface is processed and finalized on the vulcanization equipment. Figure 2 It can be seen that the outer edge of the radiating surface of the processed flat plate is designed as a metal ring, the middle part is a metal flat plate, and the middle part is a rubber folding ring. Figure 3 It is a schematic diagram of the radiation surface structure and the coil frame 6 being fixedly connected as one through screws.

[0051] 2. Using non-magnetic conductive material as the coil skeleton 6, high temperature resistance, light weight;

[0052] In order to prevent the influence of electromagnetic damping on the internal driving force performance of the sound source, the coil skeleton 6 is designed using non-magnetic conductive composite materials (such as high-temperature resistant and easy-to-form nylon, carbon fiber, etc.), which has the following advantages: light weight, no electromagnetic damping, and a temperature resistance of 120°C.

[0053] 3. The voice coil is made of two sets of coils, which are wound up and down respectively and connected in parallel, so that the impedance of the sound source is small, which is easy to match the existing mature power amplifier, and the design volume and weight of the driving amplifier of the sound source are very small;

[0054] 4. The elastic structure 16 adopts a structure in which multiple groups of springs 2 are evenly arranged in parallel, thereby improving the stability of the axial operation of the radiation surface.

[0055] The overall parameters of the elastic structure 16 are determined based on the size and weight parameters of the overall radiation surface panel 1 and the coil frame 6; the design of the specific structure is based on the internal space volume of the sound source and the convenience requirements of the sound source installation. It is designed to be located at the internal center position of the magnetic pure iron, evenly distributed, and the spring is a compression spring.

[0056] The elastic structure 16 includes: a plurality of springs 2, a plurality of guide pillars 14 and a spring support plate 15; a plurality of openings are opened on the spring support plate 15; the spring support plate 15 is fixed to a circle of the inner wall of the coil frame 6;

[0057] Each guide post 14 passes through an opening on the spring support plate 15 and is fixed on the surface of the magnetic conductive structure 8;

[0058] Each spring 2 is sleeved on the guide column 14 to adjust the vibration of the coil skeleton 6.

[0059] The guide column 14 is straight or T-shaped; when the guide column 14 is straight, the spring 2 is installed between the spring support plate 15 and the magnetic conductive structure 8; when the guide column 14 is T-shaped, the spring 2 is installed between the top of the T-shaped guide column 14 and the spring support plate 15.

[0060] 5. In order to increase the magnetic flux density in the air gap magnetic field of the magnetic circuit, the magnet 5 is a permanent magnet made of large-sized, high-performance neodymium iron boron material.

[0061] In the present invention, the low-frequency broadband transmitting sound source adopts the traditional magnetic circuit structure, and the radiation surface structure 1 adopts a flat aluminum plate design; a large-size and high-efficiency magnetic circuit is adopted, and a composite material is used as the dynamic cylinder skeleton. The structural strength is not affected, and it is high temperature resistant and light in weight; the driving coil is formed by two groups of coils wound up and down respectively and connected in parallel, so that the impedance of the sound source is small.

[0062] The new structural form (flat radiating surface, coil frame, elastic component distribution structure, and estimated connection method between the flat radiating surface and the coil) realized by the dynamic coil driving mechanism can mainly transmit sound waves in the frequency band below 1000Hz, which has the unique advantage of long propagation distance, making low-frequency broadband transmission sound sources a hot topic in the field of underwater acoustic transducers.

[0063] The present invention provides an underwater very low frequency sound source based on a traditional structural design based on a moving coil drive mechanism. Among them, the low-frequency broadband transmitting sound source adopts a traditional magnetic circuit structure, and the radiation surface adopts a flat aluminum plate design; a large-size and high-efficiency magnetic circuit is adopted, and a composite material is used as the dynamic cylinder skeleton. The structural strength is not affected, and it is high temperature resistant and light in weight; the driving coil is made of two groups of coils wound up and down respectively, and connected in parallel, so that the impedance of the sound source is small. The underwater very low frequency sound source of the new structural form realized based on the moving coil drive mechanism emits sound autonomously, and is not limited to the description in the specification and implementation method. Therefore, all equivalent changes or modifications made according to the scheme described in the scope of the patent application of this application should be included in the scope of the patent application of this invention.

[0064] 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 the present invention. Although the present invention is described in detail with reference to the embodiments, it should be understood by those skilled in the art that any modification or equivalent replacement of the technical solutions of the present invention does not depart from the spirit and scope of the technical solutions of the present invention and should be included in the scope of the claims of the present invention.

Claims

1. An underwater very low frequency sound source based on a moving coil drive mechanism, characterized in that: The sound source comprises a very low frequency transmitting module; the very low frequency transmitting module comprises: a hollow cylindrical shell (9) with openings on two sides, a magnetic conductive structure (8), a magnet (5), a moving coil linear drive structure, and a radiation surface structure (1) formed by using a metal plane plate and installed on an open surface of the shell (9); The magnetic conductive structure (8) is a hollow cylinder that matches the interior of the outer shell (9), and both the upper and lower surfaces of the hollow cylinder are provided with magnetic gaps in the shape of an annular cylinder; The magnet (5) is placed at the center of the magnetic conductive structure (8) to form an air cavity in the shape of a ring column with the magnetic conductive structure (8); The moving coil linear drive structure comprises: an annular cylindrical coil frame (6), a coil winding (7) and an elastic structure (16); The coil frame (6) is made of non-magnetic conductive material and is fixedly connected to the radiation surface structure (1) as a whole, and is used to drive the radiation surface structure (1) to vibrate through the magnetic gap and air cavity in the shape of an annular column; The coil winding (7) is formed by winding an upper coil and a lower coil frame (6) respectively, and the two coils are connected in parallel and are respectively located at the magnetic gap of the magnetic conductive structure (8); The elastic structure (16) uses multiple groups of springs (2) arranged in parallel and is placed between the coil frame (6) and the radiation surface structure (1) to control the vibration of the coil frame (6); The elastic structure (16) comprises: a plurality of springs (2), a plurality of guide pillars (14) and a spring support plate (15); The spring support plate (15) is provided with a plurality of openings; the spring support plate (15) is fixed to an inner wall of a coil frame (6); Each guide post (14) passes through an opening on the spring support plate (15) and is fixed to a surface of the magnetic conductive structure (8) opposite to the spring support plate (15); Each spring (2) is sleeved on a guide post (14) and is used to adjust the vibration of the coil frame (6); The guide column (14) is in a straight line or T-shape; When the guide column (14) is in a straight line, the spring (2) is installed between the spring support plate (15) and the magnetic conductive structure (8); When the guide post (14) is T-shaped, the spring (2) is mounted between the top of the T-shaped guide post (14) and the spring support plate (15); The other open surface of the housing (9) is provided with a mounting base (13) for mounting and fixing the magnetic conductive structure (8); the center of the mounting base (13), the centers of the two surfaces of the magnetic conductive structure (8) and the center of the magnet (5) are all open to form a gas passage; The very low frequency transmission module further comprises a connecting plate (17); the connecting plate (17) is provided with a vent (10) which is in communication with the gas channel; The sound source further comprises a pressure compensation module, the pressure compensation module comprising an air bag (11), the air bag (11) being in communication with the very low frequency transmission module via a vent (10) for achieving pressure compensation.

2. The underwater very low frequency sound source based on the dynamic coil drive mechanism according to claim 1, characterized in that: The material of the magnetic conductive structure (8) is pure iron; the material of the magnet (5) is a permanent magnet made of neodymium iron boron.

3. The underwater very low frequency sound source based on the dynamic coil drive mechanism according to claim 1, characterized in that: The coil frame (6) and the radiation surface structure (1) are fixedly connected as a whole via screws.

4. The underwater very low frequency sound source based on the dynamic coil drive mechanism according to claim 1, characterized in that: The upper and lower groups of coils of the coil winding (7) are respectively connected with lead wires.

5. The underwater very low frequency sound source based on the dynamic coil drive mechanism according to claim 1, characterized in that: The bottom of the mounting base (13) is provided with an annular groove in the shape of an annular column, which is used to provide a vibration space for the coil frame (6).

6. The underwater very low frequency sound source based on the dynamic coil drive mechanism according to claim 1, characterized in that: The pressure compensation module further comprises an airbag protection outer cylinder (12); and a gas replenishment port (4) is provided at the top of the magnetic conductive structure (8) for replenishing gas to the airbag (11) of the pressure compensation module.

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