JPH0760179B2 - Transceiver for scanning sonar - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a sonar transmitter / receiver, and particularly to reduction of screw noise.

(Prior Art and Problems Thereof) A conventional transducer for scanning sonar has a cylindrical shape in which a large number of vibrating elements are stacked in an annular shape as shown in, for example, FIG. 1 (a) transverse sectional view and (b) vertical sectional view. The vibrator group (1) arranged in the above is arranged in the dome (2), and the vibrator group (1)
(3) as acoustic coupling between the dome and the dome (2)
As shown in FIG. 2, a transducer (4) having a directivity mainly in the direction orthogonal to the cylindrical surface formed by filling the 1
It is provided in the state shown in FIG. 3B and detection is performed according to the following procedure.

That is, after simultaneously generating sound waves from the respective vibrators (1) of the cylindrical vibrator group (1) substantially in the direction of the cylindrical surface, a plurality of arranged vibrators are arranged in order to receive the reflected waves of the sound waves. The combined directional characteristic of the vibrating element is formed as shown in FIG. 5, and a plurality of element groups having this combined directional characteristic are sequentially switched while shifting one by one to receive reflected waves from each direction. Then, the reflected signal converted into an electric signal is displayed as an image on a cathode ray tube device that is spirally swept to search for a school of fish and other objects.

By the way, in this case, the ship to which the wave transmitter / receiver is attached generally has a propelling screw (6), and this screw is at the stern, that is, at the back of the wave transmitter / receiver (4) as shown in FIGS. 2 (a) and (b). It is generally located. Therefore, it is impossible to prevent the stirring noise N of the water from propagating in the water and wrapping around in front of the transducer. For this reason, screw noise that wraps around from the rear when a ship is particularly required to detect the front of the ship is received by the wave transmitter / receiver and displayed as a noise image in the front direction of the image. Therefore, if the screw noise is large, for example, the recognition of the fish school image will be erroneous, and it will not be possible to prevent the detection ability from appearing.

Therefore, in the related art, the noise level is reduced by processing the screw or reducing the boat speed during detection, that is, reducing the screw rotation speed. However, there is a limit to the method of processing the screw, and the method of decelerating cannot maximize the marine vessel maneuvering ability at the time of tracking a school of fish, and any of these methods is unsatisfactory.

(Object of the Invention) The present invention provides a transducer that can greatly prevent screw noise from sneaking in the front of the transducer by adding simple parts, and improves the ability of sonar to detect a school of fish or the like. It is a thing.

(Means of the Present Invention for Solving Problems) A feature of the present invention resides in that a sound insulating blade is provided on a side surface of the wave transmitter / receiver so as to intersect with a propagating direction of screw noise sneaking forward. Next, a specific description will be given with reference to the drawings.

(Embodiment) FIGS. 3 and 4 show an embodiment of the present invention, which is the one shown in FIG. 3 when a center plane positioned so as to divide the hull into two parts is divided into left and right parts through the bow and stern. Is provided with two sound-insulating blades (7) radially on the side surface of the transducer group (1) arranged in a cylindrical shape and at symmetrical positions on the left and right with respect to the center plane (the dome (2) is shown in the figure). Is omitted), and the screw noise (8) that tries to move forward as shown by the dotted line in the figure is isolated. The one shown in FIG. 4 is the dome (2).
This is an example in which two sound-insulating blades (7) are provided on the inner peripheral surface in the same manner as in FIG. 3, and the screw noise is most effective for the position and size of the sound-insulating blade (7) and the mounting angle. It is selected so that it can be effectively insulated. Further, as shown by dotted lines in FIGS. 3 and 4, two or more sound insulating blades (7) are provided on each of the left and right sides (two on each of the left and right sides in the drawings) to improve the sound insulating ability.

FIG. 5 is a directional characteristic diagram showing the presence or absence of the two sound insulation blades provided as described above.
The one shown by the dotted line in the figure is the case where there is no sound insulating blade. As is clear from this, there is almost no difference in the main lobe A depending on the presence or absence of the sound-insulating blade, but it is clear that there is a large difference in the characteristics of the side lobe B, especially the rear part, and the screw noise from the rear part is greatly reduced. It is shown that.

Although the present invention has been described above, it is preferable to use a material having a property of attenuating sound waves, such as stainless steel, as a material for forming the sound insulation blade. Further, the scanning sonar has been described above, but the invention can also be applied to the case of performing detection by emitting a sound wave obliquely forward with a transducer having one transducer.

(Effects of the Invention) As described above, according to the present invention, it is possible to simply use the screw noise by simply providing a plurality of simple sound-insulating blades on the transducer without requiring difficult processing such as screw processing. It can prevent the detection ability from decreasing, and its effect is extremely large.

[Brief description of drawings]

FIG. 1 is an explanatory view of a wave transceiver, FIG. 2 is an explanatory view of a state of installation of the wave transceiver on a ship, FIGS. 3 and 4 are explanatory views of an embodiment of the present invention, and FIG. FIG. 6 is a comparison diagram of directional characteristics with and without sound insulation blades. (1) …… Resonator, (2) …… Dome, (3) …… Oil,
(4) …… Transceiver, (5) …… Ship bottom, (6) …… Screw, (7) …… Sound insulation blade, (8) …… Screw noise.

Claims (1)

[Claims] 1. A vibrator group in which a plurality of vibrators are arranged in a cylindrical shape is positioned in the center of a concentric cylindrical dome, and the central axis of the vibrator group is set in the vertical direction, and the position of the screw of the ship is set. Also in a transducer for an oil-filled scanning sonar that is arranged on the bottom of the ship near the bow, a plurality of sound-insulating blades for suppressing the wraparound of screw noise due to the screw in front of the transducer is provided with the vibration. Left-right symmetry with respect to a direction that is vertical between the child group and the dome and that radiates from the central axis of the cylinder of the cylindrical vibrator group, and that is directed from the screw to the transducer. A transmitter / receiver for scanning sonar, which is provided in the.