JPH08175490A - Underwater navigating body - Google Patents

Abstract

PURPOSE: To provide an underwater navigating body which can reduce propagation of vibtation from the device interior to its wave receiver covering a wide frequency band and also withstand high depth pressure. CONSTITUTION: A minor axis part 15 of a specified length is fomed on the outer circumferential part of an underwater navigating body. A wave receiver 16 is formed in a cylindrical shape and its inside diameter is formed larger than that of the outer circumferential part of the minor axis 15. Magnets are respectively embedded in the minor axis part 15 and the part of the wave receiver 16 where it faces the minor axis part 15 and a gap 17 is formed by the resiliency of the magnets. The gap 17 is filled with water when the underwater navigating body is in the water. Because the mechanical impedance rate between the water and the metallic body is large, vibration propagation can be reduced by the gap 17 covering a wide frequency band. The wave receiver 16 is not easily deformed because its inner side and outer side are applied with equal water pressure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an underwater vehicle that sails underwater and reduces the propagation of vibrations generated inside the underwater vehicle, such as an engine for propulsion, to a wave receiving unit. Underwater vehicle.

[0002]

2. Description of the Related Art An underwater vehicle that travels underwater generally has a wave receiving unit that receives sound waves propagating in water and converts them into electric signals. The wave receiving unit is used as a sonar receiving unit for detecting an obstacle existing in the traveling direction of the underwater vehicle and for examining the shape of the seabed.

FIG. 4 shows the appearance of a conventional underwater vehicle. Underwater vehicle 101
It has a bullet-shaped body. A propulsion engine 102 is disposed on the rear end side of the main body. By rotating the screw 103 by the propulsion engine 102, it is possible to navigate underwater. A wave receiving unit 104 is buried in an outer peripheral portion of the main body, and receives a sound wave.

FIG. 5 shows a sectional structure of a substantially central portion of the underwater vehicle shown in FIG. Since the wave receiving portion 104 existing in the substantially central portion of the underwater vehicle has a cylindrical shape, the sectional structure shown in FIG. 5 is vertically symmetrical.
For this reason, in order to simplify the illustration, each component is given a reference numeral only in the upper part of the figure.

A substantially central portion of the underwater vehicle has a cylindrical shape and is made of a metal material such as an aluminum alloy having a predetermined thickness. The cylindrical portion has a short diameter at a substantially central portion over a predetermined length in the longitudinal direction of the underwater vehicle, and forms a short diameter portion 112. This short diameter portion 11
The recessed portion 2 is filled with a mold resin 113, in which the wave receiving element 114 is embedded.
In addition, a sound insulating material 115 is arranged on the outer periphery of the cylindrical metal portion of the short diameter portion 112 at a position facing the wave receiving element 114. The sound insulating material 115 is the engine 102 shown in FIG.
It serves to reduce the propagation of vibration from the wave to the wave receiving element 114. Further, the sound insulating material 115 also has an effect as a backing material for reflecting the sound wave to be received and improving the sensitivity of the wave receiving element.

The mechanical impedance of the mold resin 113 of this underwater vehicle is such that the body 111
The one that does not have a big difference from that of is used. Therefore, the vibration from the engine 102 propagates through the mold resin 113 and propagates to the wave receiving element 114, and even if the sound insulating material 115 is provided, the effect of reducing the vibration is relatively small. Body 1
The vibration from 11 becomes noise for the sound wave to be received,
It degrades the signal-to-noise ratio at the output of the receiving element 114. Therefore, various proposals have been made to reduce the propagation of vibrations from the engine 102 to the wave receiving element 114.

[0007] Japanese Utility Model Laid-Open Publication No. Hei 3-40194 and Japanese Utility Model Laid-Open Publication No. 60-109065 disclose an underwater vehicle in which a vibration isolating material is interposed between a main body portion having a vibration source such as an engine and a wave receiving portion. A running body is disclosed. Also, the actual development 63-
Japanese Patent No. 7886 discloses an underwater vehicle which suppresses vibration propagation by surrounding and fixing a wave receiving portion with a polymer foam material. In addition, a wave receiving part may be provided inside the head of the main body, and Japanese Utility Model Laid-Open No. Sho 62-44287 discloses a vibration damping material provided inside the head housing the wave receiving part. An underwater vehicle is disclosed.

[0008] JP-A-64-16980 discloses that
There is disclosed an underwater vehicle in which a pressure-resistant shell on the head is formed of a high damping material such as FRP (fiber reinforced plastic). By forming the pressure-resistant shell with a high impedance material, the propagation of vibration to the wave receiving portion housed inside is reduced. Further, in this underwater vehicle, the outer peripheral surface of the pressure shell is covered by an acoustic rubber layer supporting the wave receiving element, so that the boundary between the pressure shell and the acoustic rubber is far from the wave receiving element. By sufficiently increasing the distance between the boundary and the receiving element, noise caused by turbulence generated at the boundary during navigation is reduced to propagate to the receiving element.

Further, JP-A-2-304385 discloses that
A submersible vehicle is disclosed in which a tunable absorber having the same resonance frequency as that of the wave receiving element is provided around the wave receiving element so that the propagating vibration can be absorbed by the tuned absorber. Further, JP-A-57-168595 discloses an underwater vehicle in which a wave receiving element is arranged in a closed space filled with a liquid such as oil. The closed space is formed by the acoustic rubber to which the wave receiving element is attached, the outer shell of the main body and the back plate, and the liquid filled therein suppresses the propagation of vibration to the wave receiving element.

[0010]

In these conventional underwater vehicles, a vibration isolation material and a vibration isolation rubber are provided to reduce the propagation of vibration to the wave receiving element. However, the effect of reducing vibration by the vibration isolating material and the vibration-proof rubber is limited to a specific vibration mode and a specific frequency region, and the effect of reducing vibration over a wide frequency band cannot be obtained. Therefore, when it is desired to receive a sound wave propagating from underwater in a wide frequency range, there is a problem that a frequency band in which the signal-to-noise ratio is deteriorated due to vibration of an engine or the like is generated in the band.

When a tunable absorber is provided or the pressure-resistant shell is F
Even when formed of a high-impedance material such as RP, the propagation of vibration cannot be reduced over a wide band as in the case of the vibration isolating material or the vibration isolating rubber, and the same problem occurs. Further, the vibration isolating material and the vibration isolating rubber have a low mechanical impedance and a not so high hardness in order to obtain a vibration reducing effect. For this reason, when the water depth increases, the water is crushed and deformed by the depth pressure. For example, when the sound insulating material 115 shown in FIG. 5 is formed of rubber containing closed cells, there is a problem that the usable depth of the underwater vehicle is limited to about several tens of meters.

When a wave receiving element is arranged in a closed space filled with a liquid such as oil as disclosed in Japanese Patent Application Laid-Open No. 57-168595, a gap between the liquid and a main body made of aluminum alloy or the like is required. Has a large mechanical impedance ratio, and vibration can be reduced over a wide band. However, since water pressure is applied only from one direction of the enclosed space,
It is difficult to maintain a closed space under high water pressure,
There is a problem that the usable depth of the underwater vehicle cannot be increased.

Accordingly, a first object of the present invention is to provide an underwater vehicle capable of reducing the propagation of vibration from an engine to a wave receiving portion over a wide frequency band.

A second object of the present invention is to increase the usable depth of the underwater vehicle.

[0015]

According to the first aspect of the present invention, there is provided a main body having a substantially cylindrical shape as a whole and having a substantially central portion having a shorter diameter than an adjacent portion over a predetermined distance in the axial direction. A receiving section in which a tubular element having an inner peripheral surface slightly larger than the outer peripheral surface and disposed to cover a portion having a shorter diameter of the main body portion and in which a receiving element for receiving vibration is embedded, The underwater vehicle has a magnet disposed at a position where the short diameter portion of the main body portion and the wave receiving portion are respectively opposed to each other and for maintaining a gap therebetween by a repulsive force of each other.

That is, in the first aspect of the present invention, by maintaining a gap between the wave receiving portion and the main body by the repulsive force of the magnet, the propagation of vibration from the main body to the wave receiving portion is reduced. . Further, in water, the gap formed by the repulsive force of the magnet is filled with water. Since the mechanical impedance ratio between the water and the main body is large, it is possible to reduce the propagation of vibration in a wide frequency band. Further, since the gap is filled with water, the wave receiving unit receives the same water pressure from inside and outside thereof, so that deformation and breakage due to the water pressure hardly occur.

According to the second aspect of the invention, the wave receiving portion has a cylindrical shape, and the outer peripheral portion of the main body adjacent to both ends of the wave receiving portion has a circular shape having substantially the same diameter as the outer peripheral portion of the wave receiving portion. None,
The outer circumference of the portion with a short diameter is slightly shorter than the inner circumference of the wave receiving portion.

That is, according to the second aspect of the present invention, the wave receiving portion has a cylindrical shape, and the outer peripheral portion of the main body portion adjacent to both ends of the wave receiving portion has substantially the same diameter as the outer peripheral portion of the wave receiving portion. You are. As a result, the step difference between the wave receiving portion and the outer peripheral portion of the main body portion is reduced, the turbulent flow generated during navigation is reduced, and the resulting vibration becomes difficult to be received by the wave receiving portion.

Further, since a gap is formed between the inner peripheral portion of the wave receiving portion and the outer peripheral portion of the shorter diameter portion of the main body portion due to the repulsion of the magnet, propagation of vibration from the main body portion to the wave receiving portion is prevented. It is reduced. Further, since the wave receiving portion has a cylindrical shape, its strength against water pressure is strong, and the usable depth can be increased.

According to the third aspect of the present invention, a propulsion engine is disposed in the main body, and the wave receiving element is an element for detecting a sound wave propagating in water.

That is, according to the third aspect of the invention, the vibration of the propulsion engine arranged in the main body portion is difficult to propagate to the wave receiving element for detecting the sound wave propagating in the water due to the gap formed by the repulsive force of the magnet. Has become. Therefore, the signal-to-noise ratio of the signal output from the wave receiving element can be improved.

In the invention of claim 4, an airtight annular member is sandwiched between both end portions of the wave receiving portion and the main body portion facing them.

In other words, according to the fourth aspect of the invention, water is prevented from entering the gap formed by the repulsive force of the magnet by sandwiching the annular member for airtightness. Since the mechanical impedance between the air filled in the airtight gap and the main body is even larger than that between water, vibration propagation can be reduced more effectively in a wide frequency band.

According to the fifth aspect of the present invention, the annular member uses an O-ring as an elastic member having a large mechanical impedance ratio.

That is, according to the fifth aspect of the present invention, the annular member for airtightness uses an O-ring as an elastic member having a large mechanical impedance ratio, so that the vibration is propagated from the main body portion to the wave receiving portion along this. Can be reduced.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to embodiments.

FIG. 1 is a diagram showing a cross section of a wave receiving portion of a submerged vehicle and its periphery according to an embodiment of the present invention.
This corresponds substantially to FIG. Since the wave receiving portion 15 existing substantially at the center of the underwater vehicle has a cylindrical shape, the sectional structure shown in FIG. 5 is vertically symmetric. For this reason,
For simplicity of illustration, each component is given a reference numeral only in the upper part of the figure. The overall shape of the underwater vehicle is the same as the conventional one shown in FIG.

The main body has a structure in which a rear part 11 of the main body containing the engine (see FIG. 4) and a main body head 12 on the front end side are detachably joined to each other. It is designed to be watertight.
The main body head 12 is formed of a metal material such as an aluminum alloy having a predetermined thickness, and has a main body rear portion 11 side having a shorter diameter than its periphery over a predetermined length.

The rear portion 11 of the main body is also formed of a metal material such as an aluminum alloy having a predetermined thickness. Therefore, the main body rear part 11 and the main body head 1 are
In a state where the two are connected, a concave short-diameter portion 15 having a cross-sectional shape is formed substantially at the center of the underwater vehicle.

A cylindrical wave receiving portion 16 is disposed on the short diameter portion 15 so as to cover the short diameter portion 15. This wave receiving section 16
Has a slightly larger inner diameter than the outer diameter of the short diameter portion 15. The outer diameter of the wave receiving portion 16 is equal to the diameter of the outer peripheral portion of the main body rear portion 11 adjacent to the minor diameter portion of the minor diameter portion 15. The wave receiving unit 16 is configured such that the main body rear portion 11 and the main body
Before being joined by the bolt 3 and the bolt 14, it is fitted into the above-mentioned minor diameter portion.

The short-diameter portion 15 of the rear portion 11 of the main body and the opposite portions of the wave receiving portion 16 have the same polarity (for example, S
) Permanent magnets 18 and 19 are embedded. A gap 17 is provided at a predetermined interval between the wave receiving portion 16 and the short diameter portion 15 due to the repulsive force of these permanent magnets 18 and 19 so that the wave receiving portion 16 and the main body portions 11 and 12 maintain a non-contact state. It has become.

The wave receiving portion 16 has a cylindrical supporting portion 21 having flanges at both ends. A urethane resin 22 is filled between the two flanges of the support portion 21 so as to match the height of the flanges. A wave receiving element 23 is embedded in the urethane resin 22. Receiving element 2
The third lead wire 24 is guided to a circuit portion (not shown) of the rear portion 11 of the main body through a watertight connector 25. Support part 2
1, the main body parts 11 and 12 are each formed of an aluminum alloy.

A sound wave arriving from underwater vibrates the wave receiving element 23 via the urethane resin 22. The wave receiving element 23 is composed of a ceramic piezoelectric element, and outputs an electric signal corresponding to the vibration when receiving the vibration. As the wave receiving element 23, a piezo element, a piezoelectric rubber, or the like can be used.

FIG. 2 is a sectional view of the underwater vehicle shown in FIG. 1 in a direction perpendicular to the central axis of the wave receiving portion. The body part 12 has permanent magnets 18 at predetermined intervals in its circumferential direction.
Is arranged. Permanent magnets 19 of the same polarity are arranged on the inner peripheral surface of the support portion 21 at positions facing these magnets 18, and a gap 17 is formed by the repulsive force between them. The wave receiving element 23 is arranged inside the urethane resin 22. The underwater vehicle is adapted to receive sound waves coming from an angle within a predetermined range, and the wave receiving element 23 is provided only in a portion corresponding to the range.

When the underwater vehicle having the above-described configuration is arranged in water, the gap 17 shown in FIG. 1 is filled with water. The water in the gap 17 becomes a mechanical impedance barrier.
Therefore, the vibration generated by the engine 102
6 can be significantly reduced. Further, the mechanical impedance ratio between water and the aluminum alloy constituting the main body head 12 or the main body rear part 11 is large, and the propagation of vibration can be reduced over a wide frequency band. As a result, a frequency band with a good signal-to-noise ratio can be widened.

When the gap 17 is filled with water, the wave receiving portion 16 receives equal water pressure from the inner peripheral side and the outer peripheral side. Therefore, even if the water pressure is high, its influence is canceled out, and the repulsive force of the permanent magnets 18 and 19 makes the gap 1
7 is retained. As a result, the underwater vehicle can be used to a place where the depth pressure is high, and it is possible to navigate to a deeper place.

Modification

FIG. 3 shows a cross section of a wave receiving portion of an underwater vehicle according to a modification of the present invention. The same parts as those in FIG. 1 are designated by the same reference numerals and the description thereof will be appropriately omitted. In the underwater vehicle according to this modified example, an O (O) ring 31 is disposed at a position where the support 21 of the wave receiving unit 16 and the main body portions 11 and 12 of the underwater vehicle oppose each other. The O-ring 31 is formed of a rubber-based material, and the space between the main body portion and the wave receiving portion is made airtight to prevent water from entering the gap 17.

Therefore, when the underwater vehicle of this modification is placed in water, the gap 17 is filled with the air layer. Since the mechanical impedance of the O-ring 31 is almost equal to that of water, the propagation of vibration from the main body to the wave receiving section 16 via the O-ring 31 is small. The permanent magnets 18 are provided on the outer peripheral portion of the main body portion in the short diameter portion 15 and on the inner peripheral portion of the support portion 21, and the gap 17 is formed by the repulsive force. The same is true.

In this modification, the mechanical impedance ratio between the air existing in the gap 17 and the aluminum alloy forming the main body portions 11 and 12 is even larger than that between water and water. Therefore, propagation of vibration can be reduced more effectively by maintaining the air layer.

In this modification, since the gap 17 is filled with air, the water pressure acts only from the outer peripheral side of the wave receiving section 16. However, the support 21
Is made of an aluminum alloy having a predetermined thickness, the water receiving portion 16 is not deformed by water pressure. Furthermore, since the wave receiving portion 16 has a cylindrical shape capable of obtaining a large strength against water pressure, the navigable depth of the underwater vehicle can be increased.

Further, a uniform water pressure is applied to the cylindrical wave receiving portion 16 from all directions on its outer peripheral surface. Such an even water pressure cancels out any biased force, and the wave receiving unit 16 is arranged concentrically with the main bodies 11 and 12. Therefore, the repulsive force of the permanent magnet 18 only needs to be large enough to form the gap 17 against gravity regardless of the water pressure.

Further, in the modified example, the mechanical impedance of the air in the airtight gap 17 is significantly different from those of the aluminum alloy support 21 and the urethane resin 22, so that the effect of reflecting sound waves at the boundary is effective. large. Therefore, the air in the gap 17 has an effect as a backing material, and also plays a role of improving the receiving sensitivity of the wave receiving portion.

In addition to this, by providing a shock absorbing material made of rubber, which is thinner than the gap 17, on the surfaces of the wave receiving portion 16 and the body portion which face each other, the gap 17 is crushed by sudden acceleration at the time of starting or stopping. It is possible to prevent a situation in which the support portion 21 and the main body portions 11 and 12 cause contact damage. If the gap 17 is filled with oil such as castor oil in advance and sealed with a rubber band or the like so as to finish the boundary between the wave receiving portion and the main body more smoothly, occurrence of turbulent flow at the boundary is prevented. Noise generated by turbulence generated during navigation can be reduced.

Although the permanent magnets are used for the underwater vehicle in the embodiments and the modified examples, it is also possible to construct them by electromagnets or a combination of permanent magnets and electromagnets. In addition, it goes without saying that the overall arrangement structure of the underwater vehicle such as the position of the engine can be appropriately changed.

[0046]

As described above, according to the first aspect of the present invention, a gap is formed between the wave receiving portion and the main body portion by the repulsive force of the magnet, so that the vibration of the main body portion is reduced. Can be reduced over a wide frequency band. Further, in the water, when water enters the gap, the wave receiving portion receives equal water pressure from the inside and outside thereof, so that deformation or destruction is unlikely to occur, and the usable depth can be increased.

According to the second aspect of the present invention, the wave receiving portion is cylindrical, and the diameter of the outer peripheral portion of the main body portion adjacent to both ends thereof is substantially equal to the outer peripheral portion of the wave receiving portion. The resulting turbulence during navigation is small, and noise due to the turbulence received by the wave receiving unit is reduced. Further, since a gap is formed between the inner peripheral portion of the wave receiving portion and the outer peripheral portion of the short diameter portion of the main body portion due to the repulsion of the magnet, propagation of vibration from the main body portion to the wave receiving portion is reduced. Furthermore, since the wave receiving portion has a cylindrical shape, its strength is strong against water pressure, and the usable depth can be increased.

According to the third aspect of the present invention, the vibration of the propulsion engine disposed in the main body is propagated to the wave receiving element for detecting the sound wave propagating in the water by the gap formed by the repulsive force of the magnet. It is difficult to do. Therefore, deterioration of the signal-to-noise ratio due to engine vibration can be reduced.

According to the fourth aspect of the present invention, since the gap formed by the repulsive force of the magnet is sealed with the annular member, an air layer is maintained in the gap even in water, so that the vibration can be more effectively generated in a wide frequency band. Propagation can be reduced.

According to the fifth aspect of the present invention, since the hermetic annular member uses an O-ring as an elastic member having a large mechanical impedance ratio, vibration is transmitted from the main body to the wave receiving portion by transmitting the O-ring. Propagation can be reduced.

[Brief description of drawings]

FIG. 1 is a sectional view showing a sectional structure of a substantially central portion of an underwater vehicle according to an embodiment of the present invention.

FIG. 2 is a sectional view of the underwater vehicle shown in FIG. 1 in a state where a wave receiving unit is cut in a direction perpendicular to an axial direction.

FIG. 3 is a sectional view showing a sectional structure of a substantially central portion of an underwater vehicle according to a modified example of the present invention.

FIG. 4 is a plan view showing the appearance of a conventionally used underwater vehicle.

FIG. 5 is a sectional view showing a sectional structure of a substantially central portion of a conventional underwater vehicle.

[Explanation of symbols]

 11, 12 Body of underwater vehicle 15 Short diameter part 16 Wave receiving part 17 Gap 18, 19 Permanent magnet 21 Support part of wave receiving part 22 Urethane resin 23 Wave receiving element 31 O-ring

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location H04R 1/44 330 D

Claims (5)

[Claims] 1. A main body having a substantially cylindrical shape as a whole and having a substantially central portion having a shorter diameter than an adjacent portion over a predetermined distance in an axial direction, and a portion having the shorter diameter of the main body. A receiving part which is arranged to cover and has a receiving element embedded therein for receiving vibration, the receiving part being a cylindrical member having an inner peripheral surface slightly larger than the outer peripheral surface; An underwater vehicle comprising: a magnet disposed at a position facing each of the wave portions and a magnet for maintaining a gap therebetween by repulsive force of each other. 2. The wave receiving portion has a cylindrical shape, and an outer peripheral portion of the main body adjacent to both ends of the wave receiving portion forms a circle having substantially the same diameter as an outer peripheral portion of the wave receiving portion. The underwater vehicle according to claim 1, wherein an outer periphery of the portion having a diameter is slightly shorter than an inner periphery of the wave receiving portion. 3. A propulsion engine is disposed in the main body, and the wave receiving element is an element for detecting a sound wave propagating in water. Underwater vehicle as described. 4. An airtight annular member is sandwiched between both ends of the wave receiving portion and the main body portion facing the both ends, respectively.
Underwater vehicle described. 5. The underwater vehicle according to claim 4, wherein the annular member is an O-ring as an elastic member having a large mechanical impedance ratio.