JP2017090075A - Sound window of sonar device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve seal performance.SOLUTION: A sound transmission member 28 is located on the inner side of a window-side attachment part 26 and supported by the window-side attachment part 26. The sound transmission member 28 includes a core layer 30, an outer skin layer 32, and an inner skin layer 34. The window-side attachment part 26 includes a first frame 36 that is held between a protrusion 3202 of the outer skin layer 32 and a protrusion 3402 of the inner skin layer 34 and a second frame 38 that holds the protrusion 3402 of the inner skin layer 34 between the second frame 38 and the first frame 36. A protrusive strip 40 is provided on an area apart from the inner edge of the first frame 36. The protrusive strip 40 extends along the whole length of the first frame 36 in the extending direction. A concave 42 is provided in an area apart from the inner edge of the second frame 38. The concave 42 extends along the whole length of the second frame 38 in the extending direction and fits into the protrusive strip 40.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an acoustic window of a sonar device.

There are sonar devices mounted on ships.
For example, small high-speed boats are equipped with a sonar device at the bow of the draft to search for obstacles ahead such as whales and driftwood so that they can operate safely, or for fishing boats and marine surveys The ship is equipped with a sonar device at the bottom of the ship, which is used to detect fish schools and to measure various things on the sea floor.
The sonar device includes a housing for forming a sonar chamber that is disposed in water and has an opening, an acoustic window that closes the opening, and a transducer that is disposed in the sonar chamber and transmits and receives sound waves through the acoustic window. Yes.
Further, the sonar chamber is filled with a liquid such as water or oil so that sound waves can be efficiently transmitted and received by the transducer.
The acoustic window includes a frame-like window-side attachment portion that is attached to the housing-side attachment portion around the opening, and an acoustically transmissive member that is disposed inside the window-side attachment portion.
The sound transmissive member includes a core layer, an outer skin layer disposed on the outer surface of the core layer located on the opposite side of the sonar chamber, and an inner skin layer disposed on the inner surface of the core layer positioned on the sonar chamber side. It is configured.

The window-side mounting portion includes a protruding portion of the outer skin layer and a protruding portion of the inner skin layer portion that protrude to the outside of the outer edge portion of the core layer, and a frame-shaped first portion positioned between the protruding portions and sandwiched between the protruding portions. 1 frame, and the frame-shaped 2nd frame which is arrange | positioned facing the 1st frame and clamps the protrusion part of an inner skin layer with a 1st frame is comprised.
And a window side attaching part is fastened to a housing | casing side attaching part with a some volt | bolt, and an opening part is obstruct | occluded.

  Further, a viscoelastic body such as rubber is used as a material constituting the core layer, and a fiber reinforced plastic having higher strength than the core layer is used as a material constituting the outer skin layer and the inner skin layer. Fiber reinforced plastics use fibers such as glass fibers, carbon fibers, and resin fibers as reinforcing materials, and for example, thermosetting resins are used as base materials.

In this case, the manufacturing process of the acoustic window is as follows.
1) A rubber plate made of an unvulcanized rubber material for constituting the core layer and a plurality of prepregs constituting the outer skin layer and the inner skin layer are prepared.
2) The first frame subjected to the adhesion treatment with the outer surface facing downward is superimposed on the prepreg constituting the outer skin layer.
3) A rubber plate coated with a vulcanized adhesive is placed on the prepreg constituting the outer skin layer inside the first frame subjected to the adhesion treatment.
4) Overlaying the prepreg constituting the inner skin layer over the rubber plate coated with the vulcanized adhesive and the inner surface of the first frame.
5) The second frame subjected to the adhesion treatment is superposed on the prepreg constituting the inner skin layer. Thereafter, the rubber plate, the prepreg, the first frame, and the second frame are temporarily fixed by placing the whole in the vacuum bag and evacuating and pressing the vacuum bag. In each of the steps 2), 3), and 4), temporary fixing using a vacuum bag is also performed.
6) An assembly consisting of the rubber plate temporarily fixed as described above, the outer skin layer, the prepreg of the inner skin layer, the first frame and the second frame is placed inside the mold composed of the upper mold and the lower mold. Then, the assembly is heated in a vacuum (evacuation) state in the mold to heat the prepreg, thereby vulcanizing the rubber plate and molding the acoustic window.
Thereby, the core layer, the outer skin layer, and the inner skin layer are integrated to form an acoustically transparent member, and the outer skin layer, the inner skin layer, and the first frame and the second frame are integrated. Then, the window side attachment portion is molded.

Japanese Patent No. 5562231

However, in the process of forming an acoustic window by heating and pressurizing using a mold as described above, the thermosetting resin contained in the prepreg constituting the inner skin layer is once liquefied before curing. The pressurized liquid thermosetting resin as the base material tends to flow out from the outer edge of the fiber as the reinforcing material.
If the liquid thermosetting resin flows out of the fiber, voids are generated in the inner skin layer of the finished acoustic window, and there is a concern that the sealing performance between the acoustic window and the housing will be reduced. There is room for improvement in planning.
The present invention has been devised in view of the above circumstances, and an object thereof is to provide an acoustic window of a sonar device that is advantageous in improving the sealing performance.

In order to achieve the above object, the invention according to claim 1 includes a frame-like window-side attachment portion attached to the case-side attachment portion around the opening of the case in which a sonar chamber is formed, and the window side An acoustically transparent member disposed on the inner side of the attachment portion, the acoustically transparent member including a core layer and an outer skin layer disposed on an outer surface of the core layer located on the opposite side of the sonar chamber; An inner skin layer disposed on the inner surface of the core layer located on the sonar chamber side, and the window-side attachment portion includes a protruding portion of the outer skin layer protruding outside an outer edge portion of the core layer, and the A projecting portion of the inner skin layer portion, a frame-shaped first frame located between the projecting portions and sandwiched between the projecting portions, and a projecting portion of the inner skin layer disposed opposite to the first frame. A frame-shaped first clamped between the first frame A sonar device acoustic window in which the window-side attachment portion is fastened to the housing-side attachment portion by a plurality of bolts to close the opening, and the first frame and the second frame At a location away from the inner edge of one frame, a protrusion extending over the entire length in the extending direction of the one frame is provided, and a location away from the inner edge of the other frame of the first frame and the second frame In addition, a concave portion that extends over the entire length in the extending direction of the other frame and engages with the convex strip is provided.
According to a second aspect of the present invention, the protrusion is provided at a location near the outer edge of one of the first frame and the second frame, and the recess is the other of the first frame and the second frame. It is provided at a location near the outer edge of the frame.
According to a third aspect of the present invention, a plurality of bolt insertion holes through which the bolts are inserted are formed at locations spaced in the extending direction of the window side attachment portion, and the protrusions and the recesses are the plurality of bolt insertion holes. It is provided outside the imaginary line connecting the two.
According to a fourth aspect of the present invention, there is provided a seal member between the window side attachment portion and the housing side attachment portion, and the seal member is provided inside an imaginary line connecting the plurality of bolt insertion holes. Features.
The invention according to claim 5 is characterized in that the seal member is joined to the second frame.

According to the first aspect of the present invention, the ridge extending over the entire length in the extending direction of the first frame is provided at the location near the outer edge of the first frame, and the location near the outer edge of the second frame is A recess that extends over the entire length of the two frames in the extending direction and engages with the protrusion is provided.
Therefore, the liquid thermosetting resin can be reliably prevented from flowing out from the outer edge of the fiber by the engagement between the ridges and the recesses, and the generation of voids in the inner skin layer can be suppressed. It is advantageous in securing the sealing property between the two.
According to invention of Claim 2, 3, the length of the protrusion part of an inner skin layer can be ensured large, and it is advantageous when ensuring the sealing performance between the inner surface of a 1st frame, and the outer surface of a 2nd frame. Become.
According to the fourth aspect of the present invention, it is advantageous to ensure the sealing performance between the acoustic window and the housing without providing a seal washer.
According to the fifth aspect of the invention, it is advantageous to increase the efficiency of the operation of attaching and removing the acoustic window to the housing.

It is the perspective view which looked at the sonar apparatus which concerns on embodiment from the downward direction of the ship bottom. It is sectional drawing of the ship bottom of a sonar apparatus part. It is the expanded sectional view which cut | disconnected the attachment state of the acoustic window in the volt | bolt part. It is the expanded sectional view which cut | disconnected the attachment state of the acoustic window in the part without a volt | bolt.

Next, the present embodiment will be described with reference to the drawings.
In the present embodiment, a case where the sonar device is mounted on a hull of a ship will be described.
As shown in FIGS. 1 and 2, the sonar device 10 includes a housing 12, a sonar chamber 14, an acoustic window 16, and a transducer 18.
In the present embodiment, the housing 12 is configured to include an outer plate portion 20 on the bottom of the ship located in water, and the sonar chamber 14 is formed in a liquid-tight manner inside the housing 12.
The sonar chamber 14 is filled with a liquid such as water or oil.
This liquid has a specific gravity necessary for satisfactory transmission and reception of sound waves by the transducer 18.

An opening 22 is provided in the outer plate portion 20.
In the present embodiment, the opening 22 is rectangular, but the shape of the opening 22 is arbitrary such as circular.
A casing-side mounting portion 24 is provided on the outer plate portion 20 around the opening 22.
As shown in FIGS. 3 and 4, the housing-side mounting portion 24 includes a housing-side mounting surface 2402 that extends outside the opening 22 along the entire circumference of the opening 22 in a rectangular frame shape, and a housing-side mounting surface. A side surface 2404 connecting the outer edge of 2402 and the outer surface of the outer plate portion 20 is provided.
Screw holes 2406 are formed at a plurality of locations spaced along the extending direction of the housing side attachment surface 2402.

The acoustic window 16 closes the opening 22.
The acoustic window 16 includes a window side attachment portion 26 and an acoustic transmission member 28.
The sound transmission member 28 is formed of a material having excellent sound transmission, and is disposed inside the window side mounting portion 26 and supported by the window side mounting portion 26.
The sound transmission member 28 includes a core layer 30, an outer skin layer 32, and an inner skin layer 34.
The core layer 30 is formed in a rectangular shape having a uniform thickness and covering the entire area of the opening 22, and an outer peripheral end face of the core layer 30 is joined to an inner peripheral end face 3610 of the first frame 36 described later. ing.
As a material constituting such a core layer 30, various conventionally known materials such as viscoelastic bodies such as rubber and polyurethane can be used.
The outer skin layer 32 is bonded to the outer surface of the core layer 30 located on the side opposite to the sonar chamber 14, and is formed in a rectangular shape having a larger outline than the core layer 30.
The inner skin layer 34 is bonded to the inner surface of the core layer 30 located on the sonar chamber 14 side, and is formed in a rectangular shape having a larger outline than the core layer 30.
As materials constituting the outer skin layer 32 and the inner skin layer 34, various conventionally known materials such as fiber reinforced plastic having higher strength than the material constituting the core layer 30 can be used.
In the present embodiment, the fiber reinforced plastic uses a fiber such as glass fiber, carbon fiber, or aramid fiber as a reinforcing material, and uses a thermosetting resin as a base material.

The window-side attachment portion 26 is a portion that is attached to the housing-side attachment portion 24 around the opening 22 and has a rectangular frame shape.
As shown in FIG. 4, the window-side attachment portion 26 includes a protrusion 3202 of the outer skin layer 32 and a protrusion 3402 of the inner skin layer 34 that protrude outward from the outer edge of the core layer 30 and extend in a rectangular frame shape. One frame 36 and a second frame 38 are included.
The first frame 36 extends in a rectangular frame shape, and is positioned between the protruding portion 3202 of the outer skin layer 32 and the protruding portion 3402 of the inner skin layer 34 that protrude outward from the outer edge portion of the core layer 30. It is joined to the protrusions 3202 and 3402, and is sandwiched between the protrusions 3202 and 3402.
The second frame 38 extends in the shape of a rectangular frame, is disposed to face the first frame 36, holds the protruding portion 3402 of the inner skin layer 34 between the first frame 36, and the protruding portion of the inner skin layer 34. 3402.

Specifically, the outer skin layer 32 is located on the outer surface 3602 of the first frame 36, and the inner skin layer 34 is located on the inner surface 3604 of the first frame 36. Further, four inner peripheral end faces 3610 made of a plane are provided on the inner peripheral part of the first frame 36, and four outer peripheral end faces 3612 made of a plane are provided on the outer peripheral part.
Further, the inner skin layer 34 is located on the outer surface 3802 of the second frame 38, and the inner surface 3804 of the second frame 38 is formed as a window side mounting surface 2602 that faces the housing side mounting surface 2402 of the housing side mounting portion 24. . Further, the inner peripheral portion of the second frame 38 is provided with four inner peripheral end faces 3810 made of a plane, and the outer peripheral portion is provided with four outer peripheral end faces 3812 made of a flat surface. The end face 3612 and the outer end face 3812 of the second frame 38 are located on the same plane.
In the present embodiment, the window-side attachment portion 26 is formed with a uniform thickness that is larger than that of the sound transmission member 28. Specifically, the thickness of the first frame 36 is formed to be larger than that of the core layer 30. The inner skin layer 34 includes a portion 3410 located on the inner surface of the core layer 30 and a first edge from the outer edge of the portion 3410. It has a standing part 3412 that rises along the frame 36, and a clamping part 3414 that protrudes from the end of the standing part 3412 and is clamped between the first frame 36 and the second frame 38. The standing portion 3412 and the inner peripheral end surface 3810 of the second frame 38 are located on the same plane.

A protruding line 40 extending over the entire length in the extending direction of the second frame 38 is provided at a position away from the inner edge of the outer surface 3802 of the second frame 38. In the present embodiment, the ridge 40 is provided at a location near the outer peripheral end surface 3812 of the second frame 38.
Further, a recess 42 that extends over the entire length in the extending direction of the first frame 36 and engages with the protrusion 40 is provided at a location away from the inner edge of the inner surface 3604 of the first frame 36. In the present embodiment, the recess 42 is provided at a location near the outer peripheral end face 3612 of the first frame 36.
In the present embodiment, the ridges 40 are provided continuously on the outer peripheral end surface 3812 of the second frame 38, and the recesses 42 are provided open on the outer edge side of the first frame 36.
As shown in FIG. 3, a plurality of bolt insertion holes 46 through which the bolts 44 are inserted are formed at locations spaced in the extending direction of the window-side attachment portion 26, and the bolt insertion holes are formed in the outer skin layer 32 and the first frame 36. A counterbore 48 that communicates with 46 is formed.
The ridge 40 and the recess 42 are provided outside the imaginary line connecting the plurality of bolt insertion holes 46.
The ridges 40 and the recesses 42 are urged in a direction that is always engaged by water pressure when the sonar device 10 is used.

As shown in FIGS. 3 and 4, a seal member 50 between the window side attachment portion 26 and the housing side attachment portion 24 is interposed.
The seal member 50 is provided inside an imaginary line that connects the plurality of bolt insertion holes 46.
In the present embodiment, a groove 2610 is formed along the extending direction of the window-side attachment surface 2602, and an O-ring 5002 constituting the seal member 50 is disposed in the groove 2610.
Since the O-ring 5002 is vulcanized and bonded to the groove 2610, the O-ring 5002 is joined to the window-side mounting portion 26, so that the mounting operation and the detaching operation of the acoustic window 16 on the housing 12 are improved.
The plurality of bolts 44 inserted through the bolt insertion holes 46 are screwed into the screw holes 2406, whereby the window side mounting portion 26 is fastened to the housing side mounting portion 24, the seal member 50 is compressed, and the opening portion 22 becomes the acoustic window. 16 is watertightly closed.

With the acoustic window 16 attached to the housing 12 in this way, as shown in FIG. 4, the tip of the protruding portion 3402 of the inner skin layer 34 is located at the inner peripheral end of the ridge 40, and the protruding portion 3402 is The inner surface 3604 of the first frame 36 and the outer surface 3802 of the second frame 38 are sandwiched.
In addition, after the acoustic window 16 is attached to the housing 12 by the plurality of bolts 44, the spotting hole 48 is filled with the potting material 52.

As shown in FIGS. 1 and 2, the transducer 18 is disposed in the sonar chamber 14 via a frame 54.
The transducer 18 detects the positional relationship between the hull and the object by emitting sound waves to the object through the acoustic window 16 and receiving the reflected waves.

Next, the manufacturing process of the acoustic window 16 will be described.
The manufacturing process of the acoustic window 16 is as follows.
1) A rubber plate made of an unvulcanized rubber material for constituting the core layer 30 and a plurality of prepregs constituting the outer skin layer 32 and the inner skin layer 34 are prepared. The prepreg is in a state where fibers as a reinforcing material are impregnated with a thermosetting resin before curing as a base material.
2) On the prepreg constituting the outer skin layer 32, the outer surface 3602 is directed downward, the first frame 36 subjected to the adhesion treatment is overlaid, and the prepreg and the first frame 36 are arranged in the vacuum bag so that the vacuum bag Is temporarily fixed by vacuuming and crimping. Hereinafter, placing the vacuum bag in a vacuum bag and applying pressure by vacuuming the vacuum bag will be described as crimping by the vacuum bag.
3) A rubber plate subjected to an adhesive treatment is superposed on the prepreg constituting the outer skin layer 32 inside the first frame 36, and an outer edge end surface of the rubber plate and an inner peripheral end surface 3610 of the first frame 36 are bonded to each other. And then temporarily fixed by pressure bonding with a vacuum bag.
4) Overlaying the prepreg constituting the inner skin layer 34 over the rubber plate and the inner surface 3604 of the first frame 36, the prepreg and the inner surface 3604 of the first frame 36 are pressure-bonded by a vacuum bag and temporarily Fix it.

5) The outer surface 3802 is directed downward on the prepreg constituting the inner skin layer 34, and the second frame 38 that has been subjected to the adhesion treatment is overlaid, and the ridges 40 of the second frame 38 are made into the concave portions 42 of the first frame 36. The second frame 38, the prepreg and the first frame 36 are pressure-bonded by a vacuum bag and temporarily fixed.
6) An assembly composed of the rubber plate temporarily fixed as described above, the prepreg of the outer skin layer and the inner skin layer, the first frame 36, and the second frame 38 is a mold composed of an upper mold and a lower mold. The prepreg of each skin layer is thermally cured and the rubber plate is vulcanized to form the acoustic window 16 by heating and pressurizing while the assembly is vacuum bonded in the mold. I do.
Thereby, the core layer 30, the outer skin layer 32, and the inner skin layer 34 are integrated to form the sound transmission member 28, and the outer skin layer 32, the inner skin layer 34, the first frame 36, The second frame 38 is integrated with the window-side mounting portion 26.
7) When the molding of the acoustic window 16 is completed, the acoustic window 16 is taken out from the mold.
8) A drilling process is performed on the window-side attachment portion 26 to form a plurality of bolt insertion holes 46 and counterbore holes 48.

In the process of forming the acoustic window 16 by heating and pressurizing using a mold as described above, the thermosetting resin contained in the prepreg constituting the inner skin layer 34 is once liquefied before curing. The pressurized liquid thermosetting resin as the base material tends to flow out from the outer edge of the fiber as the reinforcing material.
When the liquid thermosetting resin flows out of the fibers, there is a concern that voids are generated in the inner skin layer 34 of the completed acoustic window 16 and the sealing performance between the acoustic window 16 and the housing 12 is deteriorated.
However, according to the present embodiment, the protrusion 40 extending over the entire length in the extending direction of the first frame 36 is provided at a location away from the inner edge of the first frame 36, and from the inner edge of the second frame 38. A recessed portion 42 that extends over the entire length in the extending direction of the second frame 38 and engages with the protrusion 40 is provided at a distant location.
Therefore, the liquid thermosetting resin can be reliably prevented from flowing out from the outer edge of the fiber by the engagement between the ridges 40 and the recesses 42, and the generation of voids in the inner skin layer 34 can be suppressed. This is advantageous in securing a sealing property between the housing 16 and the housing 12.
Note that the thermosetting resin contained in the prepreg constituting the outer skin layer 32 is also liquefied once before curing and flows out from the outer edge of the fiber. The sealing property between the window 16 and the housing 12 is not affected.
Further, the protrusion 40 is provided at the outer surface 3802 at a position between the inner peripheral end surface 3810 and the outer peripheral end surface 3812, and the concave portion 42 is provided at the inner surface 3604 at an intermediate position between the inner peripheral end surface 3610 and the outer peripheral end surface 3612. However, as in the present embodiment, the ridge 40 is provided at a location near the outer edge of the outer surface 3802 of the second frame 38, and the ridge 40 is provided at a location near the outer edge of the inner surface 3604 of the first frame 36. When the recess 42 that engages with the inner skin layer 34 is provided, the length of the protruding portion 3402 of the inner skin layer 34 can be secured large, and the sealing performance between the inner surface 3604 of the first frame 36 and the outer surface 3802 of the second frame 38 is secured. This is advantageous.
In the present embodiment, the case where the ridge 40 is provided on the second frame 38 and the recess 42 is provided on the first frame 36 has been described, but the ridge 40 is provided on the first frame 36 and the recess 42 is provided on the first frame 36. It is optional such as providing it on the two frames 38.

Further, since the protrusion 40 of the second frame 38 and the recess 42 of the first frame 36 are engaged with each other over the entire length of the second frame 38, the protrusion 40 and the first frame of the second frame 38 are engaged. When the engagement of the 36 with the recess 42 is partially disengaged, it is possible to easily determine the assembly failure between the first frame 36 and the second frame 38.
Therefore, it is possible to easily determine whether or not the first frame 36 and the second frame 38 are assembled accurately before the acoustic window 16 is formed, which is advantageous in improving the efficiency of the assembly work. Become.

Further, in the present embodiment, a plurality of bolt insertion holes 46 through which the bolts 44 are inserted at positions spaced in the extending direction of the window-side attachment portion 26 are formed, and the protrusions 40 and the recesses 42 have a plurality of bolt insertion holes. 46 is provided outside the imaginary line connecting 46.
Therefore, the length of the protruding portion of the inner skin layer 34 can be ensured to be large, which is advantageous in securing the sealing performance between the inner surface 3604 of the first frame 36 and the outer surface 3802 of the second frame 38.

Further, in the present embodiment, the seal member 50 between the window side attachment portion 26 and the housing side attachment portion 24 is interposed, and the seal member 50 is provided inside the imaginary line connecting the plurality of bolt insertion holes 46. This is advantageous in securing a sealing property between the acoustic window 16 and the housing 12.
Note that the seal member 50 may be provided outside the imaginary line connecting the plurality of bolt insertion holes 46. In that case, in order to ensure sealing performance, it is necessary to interpose a seal washer between the bolt 44 and the bolt insertion hole 46. However, in this embodiment, the seal washer can be omitted. This is advantageous for downing.

  In the embodiment, the case where the casing 12 is configured to include the outer plate portion 20 of the ship bottom has been described. However, the casing 12 is configured only by the casing 12 provided exclusively for the sonar device. It may be.

DESCRIPTION OF SYMBOLS 10 Sonar apparatus 12 Housing | casing 14 Sonar chamber 16 Acoustic window 18 Transceiver 20 Outer plate part 22 Opening part 24 Housing | casing side attaching part 26 Window side attaching part 28 Sound permeable member 30 Core layer 32 Outer skin layer 3202 Outer skin layer Protruding portion 34 Inner skin layer 3402 Protruding portion 36 of inner skin layer First frame 38 Second frame 40 Convex strip 42 Concave portion 44 Bolt 46 Bolt insertion hole 50 Seal member

Claims (5)

A frame-like window-side attachment portion that is attached to a case-side attachment portion around the opening of the case in which a sonar chamber is formed; and an acoustically transmissive member disposed inside the window-side attachment portion. ,
The sound transmitting member is disposed on a core layer, an outer skin layer disposed on the outer surface of the core layer located on the opposite side of the sonar chamber, and an inner surface of the core layer located on the sonar chamber side. It consists of an inner skin layer and
The window-side attachment portion is positioned between the protrusions and the protrusions of the outer skin layer and the protrusions of the inner skin layer that protrude outside the outer edge of the core layer, and is sandwiched between the protrusions. A frame-shaped first frame, and a frame-shaped second frame that is disposed opposite to the first frame and sandwiches the protruding portion of the inner skin layer with the first frame,
An acoustic window of a sonar device in which the window side attachment portion is fastened to the housing side attachment portion by a plurality of bolts and closes the opening,
A ridge extending over the entire length in the extending direction of the one frame is provided at a position away from the inner edge of one of the first frame and the second frame,
A recessed portion that extends over the entire length in the extending direction of the other frame and engages with the protruding strip is provided at a position away from the inner edge of the other frame of the first frame and the second frame.
An acoustic window for a sonar device. The ridge is provided at a location near the outer edge of one of the first frame and the second frame,
The recess is provided at a location near the outer edge of the other frame of the first frame and the second frame.
The acoustic window of the sonar device according to claim 1. A plurality of bolt insertion holes are formed through which the bolts are inserted at locations spaced in the extending direction of the window side attachment portion,
The ridge and the recess are provided outside an imaginary line connecting the plurality of bolt insertion holes,
The acoustic window of the sonar device according to claim 1 or 2. A seal member between the window side attachment portion and the housing side attachment portion is interposed,
The seal member is provided inside an imaginary line connecting the plurality of bolt insertion holes,
The acoustic window of the sonar device according to claim 3. The seal member is joined to the second frame;
The acoustic window of the sonar device according to claim 4.

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