Seabed imaging sonar

Abstract

The seabed imaging sonar comprises a receiving transduction module, the receiving transduction module comprises a receiving plate, an annular sealing block, a socket and a front cover, a first mounting opening is formed in the middle of the front cover, the annular sealing block is arranged at the edge of the first mounting opening, and the receiving plate is arranged at the first mounting opening; the annular sealing block is at least partially attached to the inner side face and the side edge of the receiving plate. The socket is arranged on the inner side face of the receiving plate and located in the middle of the annular sealing block. The shell is internally provided with a pressure balance cavity, the pressure balance cavity is filled with a compressible fluid medium, the side wall of the shell is provided with a second installation opening, the front cover is installed at the second installation opening, and the socket is located in the pressure balance cavity; and the piston assembly comprises a piston cylinder and a piston, the piston is movably arranged in the piston cylinder, and one end of the piston cylinder communicates with the pressure balance cavity so as to allow the compressible fluid medium to enter the piston cylinder.

Description

Technical Field

[0001] The present invention relates to the field of sonar, and particularly to a subsea imaging sonar. Background Art

[0002] Information such as deep - sea terrain, mineral distribution, and biological distribution has very considerable economic value. Among them, after the subsea imaging sonar is carried on an underwater robot (ROV) or an autonomous underwater vehicle (UUV), the above - mentioned information can be surveyed.

[0003] The subsea imaging sonar includes a housing, and a receiving transducer module and a transmitting transducer module arranged on the housing. The receiving and transmitting of sound waves are realized through the receiving transducer module and the transmitting transducer module. In order to improve the receiving sensitivity of sound waves, the receiving transducer module usually adopts a planar array design. Since the subsea pressure is very high, a support component needs to be additionally arranged inside the housing to support the receiving transducer module to reduce the deformation of the receiving transducer module.

[0004] However, to achieve the above - mentioned purpose, the support component needs to support the receiving transducer module over a large area, which results in the support component occupying a large amount of space inside the housing and interfering with other components, making it difficult for the subsea imaging sonar to be miniaturized. Summary of the Invention

[0005] Based on this, it is necessary to provide a subsea imaging sonar aiming at the problem that the subsea imaging sonar cannot balance detection sensitivity and miniaturization.

[0006] A subsea imaging sonar, comprising:

[0007] A receiving transducer module, the receiving transducer module includes a receiving board, an annular sealing block, a socket and a front cover. A first installation opening is formed in the middle of the front cover. The annular sealing block is arranged at the edge of the first installation opening. The receiving board is arranged at the first installation opening. The annular sealing block at least partially fits on the inner side surface and the side edge of the receiving board. The socket is arranged on the inner side surface of the receiving board and is located in the middle of the annular sealing block;

[0008] A housing, a pressure - balance cavity is arranged inside the housing. The pressure - balance cavity is filled with a compressible fluid medium. A second installation opening is arranged on the side wall of the housing. The front cover is installed at the second installation opening, and the socket is located in the pressure - balance cavity;

[0009] A sensor assembly, the sensor assembly is located in the pressure - balance cavity, and the sensor assembly is in plug - in fit with the socket;

[0010] The piston assembly comprises a piston cylinder and a piston, wherein the piston is movably arranged in the piston cylinder, and one end of the piston cylinder is connected to the pressure balance chamber to allow the compressible fluid medium to enter the piston cylinder.

[0011] In one embodiment, the receiving board includes a first matching layer, a receiving array layer and a circuit board which are arranged in layers in sequence, the socket is arranged on a side of the circuit board away from the receiving array layer, the projection of the receiving array layer in the normal direction avoids the annular sealing block, and the projection of the receiving array layer in the normal direction is located in the first matching layer.

[0012] In one embodiment, a portion of the annular sealing block is located between the first matching layer and the circuit board, and the annular sealing block and the first matching layer are an integral structure, so that the receiving board is radially positioned through the edge of the first mounting opening.

[0013] In one of the embodiments, the piston assembly further includes a first sealing ring, a sealing groove is provided on the side wall of the piston, and the first sealing ring is arranged at the sealing groove and pressed against the inner wall of the piston cylinder.

[0014] In one embodiment, the inner wall surface of the annular sealing block is a cylindrical surface, the shape of the receiving array layer is circular, the axis of the inner wall surface of the annular sealing block passes through the center of the receiving array layer, and the seabed imaging sonar satisfies:

[0015] ; Wherein, α is the static friction coefficient between the first sealing ring and the inner wall of the piston cylinder;

[0016] f is the dynamic friction coefficient between the first sealing ring and the inner wall of the piston cylinder;

[0017] d is the outer diameter of the first sealing ring, in mm;

[0018] e is the compression rate of the first sealing ring;

[0019] E is the elastic modulus of the first sealing ring, in MPa;

[0020] D is the inner diameter of the piston cylinder, in mm;

[0021] μ is the Poisson's ratio of the first sealing ring;

[0022] ω is the maximum deflection at the center of the receiving plate, in mm;

[0023] E1 is the elastic modulus of the first matching layer, in MPa;

[0024] t1 is the thickness of the first matching layer, with the unit of mm;

[0025] μ1 is the Poisson's ratio of the first matching layer;

[0026] E2 is the elastic modulus of the receiving array layer, with the unit of MPa;

[0027] t2 is the thickness of the receiving array layer, with the unit of mm;

[0028] μ2 is the Poisson's ratio of the receiving array layer;

[0029] E3 is the elastic modulus of the circuit board, with the unit of MPa;

[0030] t3 is the thickness of the circuit board, with the unit of mm;

[0031] μ3 is the Poisson's ratio of the circuit board;

[0032] a is the inner diameter of the annular sealing block, with the unit of mm.

[0033] In one embodiment, the thickness of the first matching layer is not greater than 0.5 mm, the thickness of the annular sealing block is not less than 10 mm, and the materials of the first matching layer and the annular sealing block are PVDF or piezoelectric ceramics.

[0034] In one embodiment, an oil filling hole is formed on the piston, the oil filling hole communicates with the pressure balance cavity, and the inner wall of the piston cylinder is used to position the air extraction pipe;

[0035] The piston assembly further includes a sealing cover, and the sealing cover is detachably installed at the oil filling hole.

[0036] In one embodiment, the subsea imaging sonar further includes a transmitting transducer module. A third installation port communicating with the pressure balance cavity is formed on the side wall of the housing. The transmitting transducer module includes a second piezoelectric layer, an acoustic absorption layer, and a second matching layer. The second matching layer covers the outer side surface of the second piezoelectric layer, the acoustic absorption layer is arranged on the inner side surface of the second piezoelectric layer, and the acoustic absorption layer is located at the third installation port.

[0037] In one embodiment, the transmitting transducer module further includes a negative electrode wire, a positive electrode wire, and a pressure-resistant layer. One end of the negative electrode wire and one end of the positive electrode wire are respectively arranged on two sides of the second piezoelectric layer. The negative electrode wire and the positive electrode wire penetrate through the acoustic absorption layer and are adhered to the acoustic absorption layer. The pressure-resistant layer is arranged on the inner side surface of the acoustic absorption layer, and the negative electrode wire and the positive electrode wire also penetrate through the pressure-resistant layer.

[0038] In one embodiment, the underwater imaging sonar further includes a rear cover assembly, which includes a rear cover, a sound absorption pad, and a power amplifier. The sound absorption pad and the power amplifier are installed on the front side of the rear cover. A fourth mounting opening is provided on the side wall of the housing, and the rear cover is installed at the fourth mounting opening so that the sound absorption pad and the power amplifier are located in the pressure balance cavity.

[0039] The beneficial effects of the present invention are as follows:

[0040] The annular sealing block is arranged at the edge of the first mounting opening and at least partially adheres to the inner side surface and the side edge of the receiving plate, which can seal the gap between the edge of the receiving plate and the edge of the first mounting opening to prevent seawater from entering the housing.

[0041] The annular sealing block adheres to the side edge of the receiving plate, which can radially limit the receiving plate. The annular sealing block adheres to the inner side surface of the receiving plate, which can support the edge of the inner side surface of the receiving plate, thereby balancing the water pressure borne by the edge of the outer side surface of the receiving plate.

[0042] When the external water pressure of the underwater imaging sonar changes, it will cause the piston to move in the piston cylinder, and then the volume and pressure of the compressible fluid medium will change. Thus, the pressure of the compressible fluid medium can always match the external water pressure of the underwater imaging sonar. Since the annular sealing block avoids the middle part of the inner side surface of the receiving plate, the compressible fluid medium can directly contact the middle part of the inner side surface of the receiving plate, and then the internal and external pressure balance of the middle part of the receiving plate is achieved.

[0043] Based on the pressure balance between the inner side surface and the outer side surface of the receiving plate, combined with the radial limit obtained by the receiving plate, the deformation of the receiving plate is effectively suppressed, ensuring the detection sensitivity of the receiving transducer module. Moreover, the fluidity of the compressible fluid medium enables it to avoid other components in the housing well and will not interfere with other components, so it will not limit the layout of the components in the housing. Therefore, replacing a large number of support components with a compressible fluid medium to achieve the internal and external pressure balance of the receiving plate can also contribute to the miniaturization of the underwater imaging sonar.

[0044] In addition, the avoidance of the middle part of the inner side surface of the receiving plate by the annular sealing block also allows the sensor assembly and the socket to be plugged and matched, thereby reducing the transmission distance between the sensor assembly and the receiving plate, significantly reducing the loss and interference during signal transmission, and at the same time improving the signal-to-noise ratio. Description of the Drawings

[0045] Figure 1 It is a three-dimensional structural schematic diagram of the underwater imaging sonar in the embodiment of the present invention;

[0046] Figure 2Schematic diagram of the explosion structure of the subsea imaging sonar in the embodiment of the present invention;

[0047] Figure 3 Schematic diagram of the three-dimensional structure of the housing in the embodiment of the present invention;

[0048] Figure 4 Schematic diagram of the cross-sectional structure of the receiving transducer module in the embodiment of the present invention Figure 1 ;

[0049] Figure 5 Schematic diagram of the three-dimensional structure of the receiving transducer module in the embodiment of the present invention;

[0050] Figure 6 Schematic diagram of the three-dimensional structure of the front cover in the embodiment of the present invention;

[0051] Figure 7 Schematic diagram of the cross-sectional structure of the receiving transducer module in the embodiment of the present invention Figure 2 ;

[0052] Figure 8 Schematic diagram of the three-dimensional structure of the sensor assembly in the embodiment of the present invention;

[0053] Figure 9 Schematic diagram of the explosion structure of the piston assembly in the embodiment of the present invention;

[0054] Figure 10 Schematic diagram of the cross-sectional structure of the piston assembly in the embodiment of the present invention Figure 1 ;

[0055] Figure 11 Schematic diagram of the three-dimensional structure and cross-sectional structure of the piston in the embodiment of the present invention;

[0056] Figure 12 Schematic diagram of the cross-sectional structure of the piston assembly in the embodiment of the present invention Figure 2 ;

[0057] Figure 13 Schematic diagram of the three-dimensional structure and cross-sectional structure of the sealing cover in the embodiment of the present invention;

[0058] Figure 14 Schematic diagram of the three-dimensional structure and cross-sectional structure of the piston assembly in another embodiment of the present invention;

[0059] Figure 15 Assembly relationship diagram of the piston assembly and the housing in another embodiment of the present invention;

[0060] Figure 16 Schematic diagram of the cross-sectional structure of the piston assembly in another embodiment of the present invention;

[0061] Figure 17Schematic three-dimensional structure of the transmitting transducer module in the embodiment of the present invention Figure 1 ;

[0062] Figure 18 Schematic cross-sectional structure of the transmitting transducer module in the embodiment of the present invention Figure 1 ;

[0063] Figure 19 Schematic three-dimensional structure of the transmitting transducer module in the embodiment of the present invention Figure 2 ;

[0064] Figure 20 Schematic cross-sectional structure of the transmitting transducer module in the embodiment of the present invention Figure 2 ;

[0065] Figure 21 Schematic three-dimensional structure diagram of the data transmitter in the embodiment of the present invention;

[0066] Figure 22 Schematic three-dimensional structure of the rear cover assembly in the embodiment of the present invention Figure 1 ;

[0067] Figure 23 Schematic three-dimensional structure of the rear cover assembly in the embodiment of the present invention Figure 2 ;

[0068] Figure 24 Schematic cross-sectional structure diagram of the rear cover assembly in the embodiment of the present invention;

[0069] Figure 25 Schematic three-dimensional structure diagram of the air extraction device in the embodiment of the present invention;

[0070] Figure 26 Usage state diagram of the air extraction device in the embodiment of the present invention.

[0071] Reference numerals:

[0072] 1. Receiving transducer module; 11. Receiving board; 111. First matching layer; 112. Receiving array layer; 113. Circuit board; 12. Annular sealing block; 13. Socket; 14. Front cover; 141. First mounting opening; 15. Retaining ring; 2. Housing; 21. Second mounting opening; 22. Third mounting opening; 23. Fourth mounting opening; 3. Sensor assembly; 31. Sensor; 32. Signal acquisition board; 4. Piston assembly; 41. Piston cylinder; 411. Limiting cover; 42. Piston; 421. Sealing groove; 422. Oil filling hole; 43. First sealing ring; 44. Sealing cover; 5. Transmitting transducer module; 51. Second piezoelectric layer; 52. Sound absorption layer; 53. Second matching layer; 54. Negative lead wire; 55. Positive lead wire; 56. Pressure-resistant layer; 57. Sleeve; 571. Wiring notch; 58. Base; 6. Rear cover assembly; 61. Rear cover; 62. Sound absorption pad; 63. Power amplifier; 7. Air extraction device; 71. Air extraction pipe; 8. Data transmitter. Detailed implementation manners

[0073] To make the above objects, features, and advantages of the present invention more apparent and understandable, the following describes the detailed implementation manners of the present invention in conjunction with the accompanying drawings. Many specific details are set forth in the following description to fully understand the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0074] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0075] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of these features. In the description of the present invention, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0076] In the present invention, unless otherwise clearly specified or limited, the terms "mounted", "connected", "coupled", "fixed", etc. shall be construed in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of two components or the interaction relationship between two components, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0077] In the present invention, unless otherwise clearly specified or limited, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "below" and "beneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0078] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or there may also be an intermediate element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time. The terms "vertical", "horizontal", "up", "down", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only embodiments.

[0079] Embodiment:

[0080] As Figure 1 and Figure 2 shown, this embodiment provides a subsea imaging sonar, including a receiving transducer module 1, a housing 2, a sensor assembly 3, a piston assembly 4, a transmitting transducer module 5, a rear cover assembly 6, and a data transmitter 8.

[0081] The function of the receiving transducer module 1 is to receive sound waves in the deep sea, specifically including a receiving plate 11, an annular sealing block 12, a socket 13, and a front cover 14.

[0082] Referring to Figure 6 , in this embodiment, the front cover 14 is generally a rectangular frame, and a first mounting opening 141 is formed in the middle of the front cover 14.

[0083] Exemplarily, as Figure 4As shown, the receiving board 11 includes a first matching layer 111, a receiving array layer 112, and a circuit board 113 that are sequentially arranged in a layered manner. Among them, the first matching layer 111 is the outer side surface of the receiving board 11, and the circuit board 113 is the inner side surface of the receiving board 11. The overall shape of the receiving board 11 is adapted to the shape of the first mounting opening 141, and the receiving board 11 is arranged at the first mounting opening 141 to block the first mounting opening 141.

[0084] The annular sealing block 12 is arranged at the edge of the first mounting opening 141. In this embodiment, the annular sealing block 12 and the first matching layer 111 are an integral structure. The annular sealing block 12 not only fits against the inner side surface of the receiving board 11 (the inner side surface of the circuit board 113), so that the annular sealing block 12 and the edge of the inner side surface of the receiving board 11 form a surface contact, but also the annular sealing block 12 simultaneously abuts against the side edge of the receiving board 11 (the side edge of the circuit board 113 and the side edge of the receiving array layer 112), so that the receiving board 11 obtains radial limitation at the first mounting opening 141.

[0085] Based on the above structure, the annular sealing block 12 can seal the gap between the edge of the receiving board 11 and the edge of the first mounting opening 141. It is not difficult to understand that in this embodiment, the edge of the inner side surface of the receiving board 11 is blocked by the annular sealing block 12, and the middle part of the inner side surface of the receiving board 11 is not blocked by the annular sealing block 12.

[0086] Among them, the coverage area of the annular sealing block 12 on the edge of the inner side surface of the receiving board 11 does not need to be very large, and only needs to meet the sealing requirements. Therefore, the space occupied by the annular sealing block 12 is small.

[0087] Combined Figure 5 and Figure 8 , the socket 13 can be arranged on the side of the circuit board 113 facing away from the receiving array layer 112, that is, the socket 13 is arranged on the inner side surface of the receiving board 11 and is located in the middle of the annular sealing block 12, so that the socket 13 and the annular sealing block 12 avoid each other, and then allow the sensor assembly 3 to be plugged and matched with the socket 13. The sensor assembly 3 can realize the electrical connection with the receiving board 11 with a shorter electrical connection path, and then significantly reduce the loss and interference in the signal transmission process.

[0088] More specifically, the sensor assembly 3 includes several sensors 31, such as attitude sensors for measuring the direction and tilt angle of the sonar, pressure sensors for measuring the underwater depth where the sonar is located, temperature sensors for measuring the ambient temperature where the sonar is located, etc. The sensor assembly 3 also includes a signal acquisition board 32. The signal acquisition board 32 is plugged and matched with the socket 13 to replace the use of some wires, and realizes the electrical connection between the elements in the receiving array layer 112 and the external circuit. The reduction of the wire usage amount can reduce the mutual interference between the corresponding transmission paths of different elements.

[0089] Such asFigure 2 and Figure 3 As shown, the shape of the housing 2 in this embodiment is generally a cuboid. A pressure balance chamber is provided inside the housing 2, and a compressible fluid medium is filled in the pressure balance chamber. The compressible fluid medium not only has a good thermal conductivity coefficient, but also its volume will expand or contract accordingly when the pressure it receives changes. The compressible fluid can specifically be industrial white oil, silicone oil or transformer oil.

[0090] Furthermore, a second installation port 21 is provided on the front side wall of the housing 2, and the second installation port 21 communicates with the pressure balance chamber. As Figure 7 shown, the shape of the outer edge of the front cover 14 is adapted to the shape of the second installation port 21, and the front cover 14 is installed at the second installation port 21 to shield the second installation port 21 by the front cover 14 and the receiving plate 11. Furthermore, a plurality of seals can be provided between the edge of the front cover 14 and the edge of the second installation port 21.

[0091] Among them, the socket 13 and the sensor assembly 3 are also located in the pressure balance chamber and are thus immersed in the compressible fluid medium. The compressible fluid medium has insulating properties and can also dissipate heat from the socket 13 and the sensor assembly 3. At the same time, due to the avoidance of the middle part of the inner side surface of the receiving plate 11 by the annular sealing block 12, the middle part of the inner side surface of the receiving plate 11 can also directly contact the compressible fluid medium and then bear the oil pressure. In contrast, as Figure 1 shown, the outer side surface of the receiving plate 11 (i.e., the first matching layer 111) can be in contact with seawater through the second installation port 21 and then bear the water pressure.

[0092] See Figure 1 and Figure 21 , in this embodiment, there are a total of two data transmitters 8. The two data transmitters 8 are installed on the housing 2 and electrically connected to the sensor assembly 3. One of the data transmitters 8 is used to transmit strong electrical signals, and the other group is used to transmit weak electrical signals, realizing the separate transmission of strong and weak electricity, thereby reducing electromagnetic interference, reducing the risk of electrical faults, and improving the overall performance of the system.

[0093] See Figure 9 and Figure 10 , the piston assembly 4 includes a piston cylinder 41 and a piston 42. The piston 42 is located inside the piston cylinder 41 and can move along the axial direction of the piston cylinder 41. The end of the piston cylinder 41 can limit the moving stroke of the piston 42 by using a limit cover 411 or reducing the diameter, etc., to prevent the piston 42 from detaching from the piston cylinder 41. This is prior art and will not be elaborated in this embodiment.

[0094] As a preference, referring to Figure 11 , a sealing groove 421 is provided on the side wall of the piston 42, and the sealing groove 421 is annular. Specifically refer to Figure 9 andFigure 10 The piston assembly 4 further includes a first sealing ring 43. The first sealing ring 43 is arranged in a ring shape at the sealing groove 421, and then the first sealing ring 43 is pressed against the inner wall of the piston cylinder 41, thereby ensuring the sealing performance between the piston 42 and the inner wall of the piston cylinder 41 during the movement of the piston 42. It is not difficult to understand that if the piston 42 is to move in the piston cylinder 41, it needs to overcome the frictional force between the first sealing ring 43 and the inner wall of the piston cylinder 41.

[0095] See Figure 12 The piston cylinder 41 is installed on the housing 2 so that one end of the piston cylinder 41 communicates with the pressure balance chamber. Thus, as the piston 42 moves in the piston cylinder 41, the compressible fluid medium in the pressure balance chamber can enter and exit the piston cylinder 41.

[0096] In this embodiment, most of the piston cylinder 41 is exposed outside the housing 2. In some other embodiments, as Figures 14 - 16 shown, most of the piston cylinder 41 can also be immersed in the housing 2, so as to further reduce the volume of the subsea imaging sonar.

[0097] See again Figure 4 In this embodiment, the inner side edge portion of the receiving plate 11 is supported in a planar manner by the annular sealing block 12. Among them, in order to meet the requirements of sealing reliability, the thickness of the annular sealing block 12 is relatively thick, generally not less than 10 mm, so the upper limit of the supporting force that the annular sealing block 12 can provide for the inner side edge of the receiving plate 11 is relatively high. When the subsea imaging sonar is located in deep sea, the outer side edge of the receiving plate 11 bears a large water pressure. At the same time, the annular sealing block 12 can provide sufficient supporting force for the inner side edge of the receiving plate 11 to balance the above water pressure, so that the internal and external pressures at the edge of the receiving plate 11 can be relatively balanced.

[0098] Furthermore, as the depth of the subsea imaging sonar in the deep sea changes, the water pressure borne by the outer side of the receiving plate 11 will also change. This pressure change will cause a pressure difference between the two sides of the piston 42, and then the piston 42 will move in the piston cylinder 41. As the piston 42 moves, the volume of the compressible fluid medium will also change. Correspondingly, the pressure of the compressible fluid medium will also change until the pressure of the compressible fluid inside the piston 42 is roughly balanced with the water pressure outside the piston 42.

[0099] It can be seen from this that the pressure of the compressible fluid medium in this embodiment will be dynamically adjusted with the change of the seawater pressure on the outer side of the receiving plate 11. In other words, the pressure of the compressible fluid medium can always roughly match the external seawater pressure. Under the condition that the middle part of the receiving plate 11 does not obtain the supporting effect of the annular sealing block 12, the oil pressure can be used to balance the external water pressure, realizing the rough balance of the internal and external forces on the middle part of the receiving plate 11.

[0100] The pressure between the inner side and the outer side of the receiving board 11 is generally balanced. Coupled with the radial limiting effect obtained by the annular sealing block 12 at the first mounting port 141 of the receiving board 11, the deformation generated by the receiving board 11 can be effectively suppressed, thereby improving the detection sensitivity of the subsea imaging sonar.

[0101] Among them, since the annular sealing block 12 has a small volume and the contact area between the annular sealing block 12 and the edge of the inner side of the receiving board 11 is not large, the occupied space of the annular sealing block 12 in the housing 2 is not large. Further, the compressible fluid medium will not interfere with the layout of the sensor assembly 3 due to its own fluidity. Therefore, the housing 2 does not need to specifically increase its volume to fill the compressible fluid medium. Considering the above two factors, the subsea imaging sonar of this embodiment further realizes miniaturization while improving the detection sensitivity.

[0102] Specifically, in this embodiment, the first matching layer 111 can be used to enhance the penetration depth and resolution of sound waves, and at the same time, it is also used to protect the receiving array layer 112 and the circuit board 113 to prevent seawater from corroding the receiving array layer 112. Therefore, the projections of the circuit board 113 and the receiving array layer 112 in the normal direction are located within the first matching layer 111. In order to achieve effective electrical connection between the receiving array layer 112 and the circuit board 113, the projection of the receiving array layer 112 in the normal direction is located within the circuit board 113.

[0103] Further, the materials of the first matching layer 111 and the annular sealing block 12 can be PVDF or piezoelectric ceramics.

[0104] Preferably, the projection of the receiving array layer 112 in the normal direction avoids the annular sealing block 12, and the projection of the receiving array layer 112 in the normal direction completely falls in the middle of the annular sealing block 12. Thus, the same medium (compressible fluid medium) can be provided at the rear sides of different positions of the receiving array layer 112, and then the acoustic impedance of different positions of the receiving array layer 112 can be maintained relatively consistent.

[0105] Exemplarily, in this embodiment, the shapes of the first matching layer 111 and the circuit board 113 are both square. As Figure 5 shown, the edge part of the inner side of the circuit board 113 is blocked by the annular sealing block 12, and the shape of the unblocked part is consistent with the shape of the receiving array layer 112.

[0106] Similarly, the shape of the receiving array layer 112 is circular. Correspondingly, the inner wall surface of the annular sealing block 12 is a cylindrical surface, and the axis of the inner wall surface of the annular sealing block 12 passes through the center of the receiving array layer 112. Since the shapes of the first matching layer 111, the receiving array layer 112, and the circuit board 113 do not match, a gap is also generated between the edge of the first matching layer 111 and the edge of the circuit board 113, and this gap is located at the edge of the receiving array layer 112.

[0107] Based on the above situation, in this embodiment, the potting process is adopted to prepare the annular sealing block 12 and the first matching layer 111 simultaneously, so that the annular sealing block 12 and the first matching layer 111 are an integral structure. Refer to Figure 4 and Figure 5 , the receiving transducer module 1 of this embodiment further includes a retaining ring 15. The retaining ring 15 is pressed on the inner side surface of the circuit board 113, so as to enclose a space with the front cover 14. At the same time, the edge of the circuit board 113 and the receiving array layer 112 are both spaced from the edge of the first mounting opening 141, so that the space enclosed by the retaining ring 15 and the front cover 14 communicates with the side of the receiving array layer 112 facing away from the circuit board 113. By injecting potting material into the space enclosed by the retaining ring 15 and the front cover 14, the annular sealing block 12 and the first matching layer 111 of the integral structure can be prepared simultaneously. Correspondingly, the finally prepared annular sealing block 12 will be attached to the retaining ring 15, and at the same time, a part of the annular sealing block 12 will be located between the first matching layer 111 and the circuit board 113, thereby effectively ensuring the sealing performance at the edge of the first mounting opening 141, and also realizing the abutment of the annular sealing block 12 against the side edge of the receiving array layer 112. At this time, the first matching layer 111, the receiving array layer 112, and the circuit board 113 can all be abutted against the edge of the first mounting opening 141 through the annular sealing block 12, so as to obtain radial positioning.

[0108] It should be noted that according to the conventional working frequency of the subsea imaging sonar, the thickness of the first matching layer 111 is generally less than 0.5 mm, or even only about 0.1 mm. Therefore, the first matching layer 111 cannot enable the receiving board 11 to have good anti-deformation performance. Therefore, in this embodiment, the receiving board 11 still mainly reduces deformation through the balance of oil pressure and water pressure.

[0109] In this embodiment , where is the minimum pressure difference required between the inside and outside of the piston 42 when the piston 42 moves against the friction force between the first sealing ring 43 and the inner wall of the piston cylinder 41.

[0110] In this embodiment , is the maximum pressure difference that the receiving board 11 can allow between the inside and outside under the condition of meeting the acoustic detection requirements. In other words, when the pressure difference between the inside and outside of the receiving board 11 is greater than When the deformation amount of the receiving plate 11 is large, it cannot meet the requirements of acoustic detection.

[0111] Where α is the static friction coefficient between the first sealing ring 43 and the inner wall of the piston cylinder 41; f is the dynamic friction coefficient between the first sealing ring 43 and the inner wall of the piston cylinder 41; d is the outer diameter of the first sealing ring 43, in mm; e is the compression ratio of the first sealing ring 43; E is the elastic modulus of the first sealing ring 43, in MPa; D is the inner diameter of the piston cylinder 41, in mm; μ is the Poisson's ratio of the first sealing ring 43; ω is the maximum deflection at the center position of the receiving plate 11, in mm; E1 is the elastic modulus of the first matching layer 111, in MPa; t1 is the thickness of the first matching layer 111, in mm; μ1 is the Poisson's ratio of the first matching layer 111; E2 is the elastic modulus of the receiving array layer 112, in MPa; t2 is the thickness of the receiving array layer 112, in mm; μ2 is the Poisson's ratio of the receiving array layer 112; E3 is the elastic modulus of the circuit board 113, in MPa; t3 is the thickness of the circuit board 113, in mm; μ3 is the Poisson's ratio of the circuit board 113; a is the inner diameter of the annular sealing block 12, in mm.

[0112] In order to meet the requirements of acoustic detection of the receiving plate 11, before the pressure difference between the inside and outside of the receiving plate 11 reaches the piston 42 must start to move. Therefore, it should satisfy less than , that is, the seafloor imaging sonar of this embodiment satisfies:

[0113] .

[0114] As Figure 11 shown, an oil filling hole 422 is provided on the piston 42 of this embodiment. The oil filling hole 422 communicates with the pressure balance cavity. Compressible fluid medium can be filled into the pressure balance cavity through the oil filling hole 422. At the same time, the air in the pressure balance cavity can also be discharged from the pressure balance cavity through the oil filling hole 422.

[0115] As Figure 25 and Figure 26 shown, when discharging the air in the pressure balance cavity, an air extraction device 7 can be used. During the air extraction process, the inner wall of the piston cylinder 41 can be used to position the air extraction pipe 71 of the air extraction device 7, so as to better maintain the negative pressure environment outside the oil filling hole 422 and improve the air extraction effect. During the air extraction process, part of the compressible fluid medium will be sputtered out from the oil filling hole 422 by the air. This part of the sputtered compressible fluid medium will reach the inner wall of the air extraction pipe 71 and then fall under the action of gravity and return to the pressure balance cavity through the oil filling hole 422.

[0116] AsFigure 13 As shown, the piston assembly 4 of this embodiment further includes a sealing cover 44, and the sealing cover 44 is detachably and cooperatively connected with the piston 42. Refer to Figure 12 , after the oil filling and exhaust operations in the pressure balance chamber are completed, the sealing cover 44 can be installed at the oil filling hole 422 to seal the oil filling hole 422.

[0117] Refer to again Figure 2 and Figure 3 , a third installation port 22 communicating with the pressure balance chamber is further opened on the front side wall of the housing 2, and the transmitting transducer module 5 is installed at the third installation port 22. The transmitting transducer module 5 is used to emit sound waves.

[0118] As Figures 17 - 19 shown, the transmitting transducer module 5 includes a second piezoelectric layer 51, an acoustic absorption layer 52, a second matching layer 53, a sleeve 57, and a base 58. One end of the sleeve 57 is fixed on the base 58, the second piezoelectric layer 51 is arc-shaped and arranged at the other end of the sleeve 57, the second matching layer 53 covers the outer side surface of the second piezoelectric layer 51, the acoustic absorption layer 52 is located inside the sleeve 57 and arranged on the inner side surface of the second piezoelectric layer 51, and the acoustic absorption layer 52 obtains radial limitation through the sleeve 57.

[0119] Furthermore, the second matching layer 53 can also cover the outer wall surface of the sleeve 57 to improve the sealing performance.

[0120] As Figure 20 shown, the base 58 is fixed on the housing 2 so that the acoustic absorption layer 52 is located at the third installation port 22.

[0121] In some other embodiments, the rear side surface of the acoustic absorption layer 52 can directly contact the compressible fluid medium, so as to balance the water pressure conducted by the second matching layer 53 by using the pressure of the compressible fluid medium. Based on the radial limitation effect obtained by the acoustic absorption layer 52, the deformation of the acoustic absorption layer 52 is effectively inhibited, thereby maintaining the sound absorption effect of the acoustic absorption layer 52 on the sound waves.

[0122] Specifically refer to Figure 18 , the transmitting transducer module 5 further includes a negative electrode wire 54 and a positive electrode wire 55. The negative electrode wire 54 and the positive electrode wire 55 penetrate through the acoustic absorption layer 52 and are adhered to the acoustic absorption layer 52. Among them, one end of the negative electrode wire 54 and one end of the positive electrode wire 55 are respectively arranged on two sides of the second piezoelectric layer 51, and the other end of the negative electrode wire 54 and the other end of the positive electrode wire 55 are connected to the sensor assembly 3.

[0123] As Figure 19As shown, a wire routing notch 571 is provided at the end edge of the sleeve 57. The negative wire 54 or the positive wire 55 can pass through the wire routing notch 571 to be connected to the outer side of the second piezoelectric layer 51. Subsequently, when preparing the second matching layer 53, the second matching layer 53 can block the wire routing notch 571.

[0124] Refer again to Figure 18 , the transmitting transducer module 5 of this embodiment further includes a pressure-resistant layer 56. The pressure-resistant layer 56 is provided on the inner side of the sound-absorbing layer 52 and is clamped between the sound-absorbing layer 52 and the base 58. The negative wire 54 and the positive wire 55 also penetrate through the pressure-resistant layer 56. Although the pressure-resistant layer 56 prevents the sound-absorbing layer 52 from directly contacting the compressible fluid medium, the pressure-resistant layer 56 can directly support the sound-absorbing layer 52 to balance the water pressure, thereby suppressing the deformation of the sound-absorbing layer 52. Moreover, since the pressure-resistant layer 56 is not easily deformed, the pressure-resistant layer 56 can achieve a good positioning effect on the negative wire 54 and the positive wire 55, restricting the bending of the negative wire 54 and the positive wire 55 at the rear side of the sound-absorbing layer 52, thereby ensuring the adhesion effect between the negative wire 54 and the positive wire 55 and the sound-absorbing layer 52.

[0125] Refer to Figures 22 - 24 , the rear cover assembly 6 of this embodiment includes a rear cover 61, a sound-absorbing pad 62, and a power amplifier 63. The sound-absorbing pad 62 and the power amplifier 63 are installed on the front side of the rear cover 61. Refer again to Figure 2 and Figure 3 , a fourth mounting opening 23 is provided on the side wall of the housing 2. The rear cover 61 is installed at the fourth mounting opening 23 so that the sound-absorbing pad 62 and the power amplifier 63 are located in the pressure balance chamber.

[0126] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0127] The above-described embodiments only represent several implementation manners of the present invention. Their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the invention patent should be subject to the appended claims.

Claims

1. An underwater imaging sonar, characterized in that, Comprising: A receiving transducer module (1), the receiving transducer module (1) includes a receiving board (11), an annular sealing block (12), a socket (13) and a front cover (14). A first mounting opening (141) is formed in the middle of the front cover (14). The annular sealing block (12) is arranged at the edge of the first mounting opening (141). The receiving board (11) is arranged at the first mounting opening (141). At least part of the annular sealing block (12) fits against the inner side surface and the side edge of the receiving board (11). The socket (13) is arranged on the inner side surface of the receiving board (11) and is located in the middle of the annular sealing block (12); A housing (2), a pressure balance chamber is arranged inside the housing (2), the pressure balance chamber is filled with a compressible fluid medium, a second mounting opening (21) is arranged on the side wall of the housing (2), the front cover (14) is installed at the second mounting opening (21), and the socket (13) is located inside the pressure balance chamber; A sensor assembly (3), the sensor assembly (3) is located inside the pressure balance chamber, and the sensor assembly (3) is in plug-in fit with the socket (13); A piston assembly (4), the piston assembly (4) includes a piston cylinder (41) and a piston (42). The piston (42) is movably arranged inside the piston cylinder (41). One end of the piston cylinder (41) is communicated with the pressure balance chamber to allow the compressible fluid medium to enter the piston cylinder (41).

2. The undersea imaging sonar according to claim 1, wherein The receiving board (11) includes a first matching layer (111), a receiving array layer (112) and a circuit board (113) which are arranged in a layered manner in sequence. The socket (13) is arranged on the side of the circuit board (113) facing away from the receiving array layer (112). The projection of the receiving array layer (112) in the normal direction is offset from the annular sealing block (12), and the projection of the receiving array layer (112) in the normal direction is located inside the first matching layer (111).

3. The underwater imaging sonar according to claim 2, characterized in that, A part of the annular sealing block (12) is located between the first matching layer (111) and the circuit board (113), and the annular sealing block (12) and the first matching layer (111) are of an integral structure, so that the receiving board (11) obtains radial positioning through the edge of the first mounting opening (141).

4. The underwater imaging sonar according to claim 2, wherein The piston assembly (4) further includes a first sealing ring (43). A sealing groove (421) is arranged on the side wall of the piston (42). The first sealing ring (43) is arranged around the sealing groove (421) and is pressed against the inner wall of the piston cylinder (41).

5. The seafloor imaging sonar according to claim 4, wherein The inner wall surface of the annular sealing block (12) is a cylindrical surface, the shape of the receiving array layer (112) is circular, the axis of the inner wall surface of the annular sealing block (12) passes through the center of the receiving array layer (112), and the subsea imaging sonar satisfies: ； Wherein, α is the static friction coefficient between the first sealing ring (43) and the inner wall of the piston cylinder (41); f is the dynamic friction coefficient between the first sealing ring (43) and the inner wall of the piston cylinder (41); d is the outer diameter of the first sealing ring (43), in mm; e is the compression ratio of the first sealing ring (43); E is the elastic modulus of the first sealing ring (43), in MPa; D is the inner diameter of the piston cylinder (41), in mm; μ is the Poisson's ratio of the first sealing ring (43); ω is the maximum deflection at the center position of the receiving plate (11), in mm; E1 is the elastic modulus of the first matching layer (111), in MPa; t1 is the thickness of the first matching layer (111), in mm; μ1 is the Poisson's ratio of the first matching layer (111); E2 is the elastic modulus of the receiving array layer (112), in MPa; t2 is the thickness of the receiving array layer (112), in mm; μ2 is the Poisson's ratio of the receiving array layer (112); E3 is the elastic modulus of the circuit board (113), in MPa; t3 is the thickness of the circuit board (113), in mm; μ3 is the Poisson's ratio of the circuit board (113); a is the inner diameter of the annular sealing block (12), in mm.

6. The seafloor imaging sonar according to claim 5, characterized in that, The thickness of the first matching layer (111) is not greater than 0.5 mm, the thickness of the annular sealing block (12) is not less than 10 mm, and the materials of the first matching layer (111) and the annular sealing block (12) are PVDF or piezoelectric ceramics.

7. The seafloor imaging sonar according to claim 5, characterized in that, An oil filling hole (422) is provided on the piston (42), the oil filling hole (422) communicates with the pressure balance cavity, and the inner wall of the piston cylinder (41) is used to position the air extraction pipe (71); The piston assembly (4) further includes a sealing cover (44), and the sealing cover (44) is detachably installed at the oil filling hole (422).

8. The underwater imaging sonar according to claim 1, characterized in that, The subsea imaging sonar further includes a transmitting transducer module (5), a third installation port (22) communicating with the pressure balance cavity is provided on the side wall of the housing (2), the transmitting transducer module (5) includes a second piezoelectric layer (51), an acoustic absorption layer (52) and a second matching layer (53), the second matching layer (53) covers the outer side surface of the second piezoelectric layer (51), the acoustic absorption layer (52) is arranged on the inner side surface of the second piezoelectric layer (51), and the acoustic absorption layer (52) is located at the third installation port (22).

9. The seabed imaging sonar according to claim 8, characterized in that, The transmitting transducer module (5) further includes a negative lead wire (54), a positive lead wire (55) and a pressure-resistant layer (56), one end of the negative lead wire (54) and one end of the positive lead wire (55) are respectively arranged on two sides of the second piezoelectric layer (51), the negative lead wire (54) and the positive lead wire (55) penetrate through the acoustic absorption layer (52) and are adhered to the acoustic absorption layer (52), the pressure-resistant layer (56) is arranged on the inner side surface of the acoustic absorption layer (52), and the negative lead wire (54) and the positive lead wire (55) also penetrate through the pressure-resistant layer (56).

10. The seafloor imaging sonar according to claim 1, wherein The underwater imaging sonar further includes a rear cover assembly (6), the rear cover assembly (6) includes a rear cover (61), a sound absorption pad (62), and a power amplifier (63), the sound absorption pad (62) and the power amplifier (63) are installed on the front side of the rear cover (61), a fourth mounting opening (23) is provided on the side wall of the housing (2), and the rear cover (61) is installed at the fourth mounting opening (23) so that the sound absorption pad (62) and the power amplifier (63) are located in the pressure balance cavity.

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