JPH06100649B2 - Baffle for sonar - Google Patents

Description

TECHNICAL FIELD The present invention relates to a baffle in which a transducer is fixedly supported in a sonar.

[Conventional technology]

The transducer used in a sonar needs to avoid the influence of unnecessary sound pressure in order to obtain a predetermined characteristic. Therefore, when the sonar is constructed, it is usually baffled so that the transducers are arranged in a predetermined arrangement. It adheres to and supports it.

Two types of conventional baffles, soft type and hard type, are known. As the soft type baffle, for example, a small air chamber sealed with a rubber material such as neoprene is known. ing.

This aims at the perfect soft reflection of unnecessary sound pressure incident on the baffle by utilizing the property of air whose acoustic impedance is extremely lower than that of water.

Further, the hard type baffle is configured by using a rigid material such as metal, which is the opposite of the soft type baffle, and has a higher acoustic impedance than water,
It is aimed at rigid reflection.

[Problems to be solved by the invention]

However, the conventional two types of baffles described above each have the following problems.

In other words, the soft type baffle reduces the air chamber when water pressure is applied, and as a result, the acoustic impedance approaches water and the sound permeability is good, so the baffle function is significantly reduced, and therefore under high water pressure. There is a problem that it can not be used in.

On the other hand, the hard type baffle needs to be thick enough to have an acoustic impedance sufficiently higher than that of water, so that it becomes very heavy so that it can be used even at low frequencies. There is.

The present invention has been made to solve these problems, and an object of the present invention is to realize a sonar baffle that can be used under high water pressure, is lightweight, and has an excellent baffling function.

[Means for solving problems]

In order to achieve this object, the present invention provides a water resistant pressure shell made of a rigid material, a sealed air chamber formed by the water resistant pressure shell, and a water pressure resistant shell which is attached to the surface of the water resistant pressure shell and is transferred to the outer peripheral surface. It is characterized by comprising a wave container and a vibration damping material mainly composed of rubber that is fixedly supported.

[Action]

In the present invention having the above-described configuration, of the sound pressure incident on the baffle, the high-frequency sound pressure is reflected by the water pressure resistant shell, and the low frequency sound pressure transmitted through this water resistant pressure shell is converted into It can be completely reflected by the air in the air chamber.

Furthermore, the resonance phenomenon of the water pressure resistant shell and the re-radiation of the sound pressure obliquely incident on the water pressure resistant shell are suppressed and reduced by the damping material attached to the surface of the water pressure resistant shell. Prevents disturbance of the sound field.

Therefore, according to this, by using the water pressure resistant shell, the air chamber is not reduced by the water pressure, it is possible to use under high water pressure, while the water pressure resistant shell is made of a rigid material, Since it is not necessary to increase the plate thickness, it can be made lightweight, and at the same time the incident sound pressure is completely reflected by the water pressure resistant shell and the air chamber, and at the same time, the sound field of the receiver output is disturbed by the damping material Since it can be prevented, an excellent baffling function that can stabilize the characteristics of the receiver output can be expected.

〔Example〕

 Embodiments will be described below with reference to the drawings.

FIG. 1 is a front view showing an embodiment of a sonar baffle according to the present invention. In the figure, 1 is a water pressure resistant shell, 2 is a damping material (damping material), and 3 is a wave transmitter / receiver.

The water pressure resistant shell 1 is formed of a rigid material such as metal or resin so as to withstand high water pressure, and has, for example, a shape having a dome-shaped portion above and below a cylindrical body. An air chamber 1a sealed by 1 is formed.

Further, the damping material 2 is mainly composed of rubber, and by sticking the damping material 2 on the surface of the water pressure resistant shell 1, the sonar baffle of the present embodiment is constituted, and the transducer 3 are fixed to the outer peripheral surface of the damping material 2 in a predetermined arrangement.

In the present embodiment, the damping material 2 has a wave receiving area of 130
%, 90% of the surface area of the water pressure resistant shell 1 is adhered.

Explaining the operation of the above-described structure, first, since the water pressure resistant shell 1 is made of a rigid material, the water pressure resistant shell 1 itself can reflect a certain amount of incident sound pressure, that is, high frequency sound pressure. it can.

Here, a part of the incident sound pressure is transmitted through the water pressure resistant shell 1, but since the water pressure resistant shell 1 can withstand high water pressure as described above, the air chamber 1a inside thereof can be contracted by the water pressure. Therefore, the sound pressure transmitted through the water pressure resistant shell 1, that is, the sound pressure of the low frequency can be completely reflected by the air in the air chamber 1a.

That is, the frequency characteristics of the baffle for sonar in this embodiment are close to those of the soft type at low frequencies, close to those of the hard type at high frequencies, and the sound pressure reflectance is close to 1 over the entire frequency band. , The sound pressure transmittance is close to 0, and a sufficient bubbling function can be obtained.

On the other hand, since the damping material 2 is mainly composed of rubber, it has an impedance equivalent to that of water with respect to the incident sound pressure of the water pressure resistant shell 1, and performs the following actions without deteriorating the buffling function of the water pressure resistant shell 1. .

That is, when only the water pressure resistant shell 1 made of a rigid material is used as a baffle, a resonance phenomenon occurs in the water pressure resistant shell 1 due to the incident sound pressure, and the sound pressure obliquely incident on the water pressure resistant shell 1 is the water pressure resistant pressure. Since they propagate through the shell 1 and are re-radiated, they disturb the sound field at the receiving point of the transducer 3 and disturb the directivity of the output of the receiver.

Therefore, in this embodiment, the damping material 2 is attached to the surface of the water pressure resistant shell 1, and the vibration damping material 2 suppresses the resonance of the water pressure resistant shell 1 and re-radiates the propagating sound pressure. It can be reduced to prevent the disturbance of the sound field at the receiving point.

FIG. 2 is a diagram showing the horizontal directional characteristics of the single CH receiver output in the embodiment of FIG. 1, in which the diameter of the water resistant pressure shell 1 to which the damping material 2 is attached is 75 cm, and the measurement frequency is 6 KHz. The case is shown as an example. FIG. 3 is a single CH when only the water pressure resistant shell 1 is used as a baffle for comparison with the embodiment.
2 shows the horizontal directional characteristic of the receiver output, and the conditions are the same as in the case of FIG.

As is clear from FIG. 3, the directional characteristics are greatly disturbed by the sound field disturbance only with the water resistant pressure shell 1, but in the case of the water resistant pressure shell 1 to which the damping material 2 is attached, that is, in the case of this embodiment. Is
As shown in FIG. 2, it is understood that the directional characteristics are not disturbed so much, and the vibration damping material 2 prevents the disturbance of the sound field.

〔The invention's effect〕

As described above, according to the present invention, the following effects can be obtained because the structure has the structure in which the damping material is attached to the surface of the water pressure resistant shell forming the sealed air chamber.

First, since the water pressure resistant shell that can withstand high water pressure is used, the air chamber in this water resistant pressure shell is not compressed, and it can be used under high water pressure.

In addition, since the incident sound pressure is reflected by the water pressure resistant shell and the air chamber, it is possible to perform sound pressure reflection over the entire frequency band, which allows the water pressure resistant shell to have the same plate thickness as the conventional hard type. Since it is not necessary to make it thick, it is possible to make it lightweight, and since the water resistant pressure shell has a large buoyancy in water because it contains an air chamber, the weight in water is further lightened, so it is extremely useful as an underwater structure. Be advantageous to.

Furthermore, the resonance phenomenon of the water pressure resistant shell and the re-radiation of sound pressure obliquely incident on the water pressure resistant shell can be suppressed or reduced by the damping material attached to the surface of the water pressure resistant shell. Since it is possible to prevent the disturbance of the wave receiving point of the wave transmitter / receiver and to obtain a stable directional characteristic, it exhibits an excellent function as a baffle of the wave transmitter / receiver in the sonar.

[Brief description of drawings]

FIG. 1 is a front view showing one embodiment of a sonar baffle according to the present invention, FIG. 2 is a view showing a horizontal directional characteristic of a receiver output when the embodiment is used, and FIG. 3 is only a water pressure resistant shell. It is a figure which shows the horizontal directional characteristic of a receiver output when using. 1: Water resistant pressure shell, 2: Damper, 3: Transducer

Claims (1)

[Claims] 1. A water-resistant pressure shell made of a rigid material, a sealed air chamber formed by the water-resistant pressure shell, and affixed to the surface of the water-resistant pressure shell, and fixedly supported by a transducer on the outer peripheral surface. A baffle for a sonar, which is provided with a vibration damping material containing rubber as a main component.