JP2537501Y2 - Underwater ultrasonic transducer - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an underwater ultrasonic transducer which is provided by molding a vibrator assembly.

[0002]

2. Description of the Related Art Underwater ultrasonic transducers are devices used for sonars, fish finder, and the like. That is, it is used in a device that descends into the water from the bottom of the ship, transmits ultrasonic waves into the water, and receives reflected waves, thereby knowing the presence and position of the detection target in the water.

In an underwater ultrasonic transducer, a vibrator made of a piezoelectric material such as PZT is used as a means for transmitting and receiving ultrasonic waves. The vibrator generates an ultrasonic wave by applying a voltage to an electrode formed on the surface, and conversely, when the ultrasonic wave is incident, converts the ultrasonic wave into an electric signal and outputs the electric signal from the electrode. It is.

An underwater ultrasonic transducer is a device in which a predetermined number of such transducers are arranged at predetermined positions and the required directivity is maintained.

FIG. 9 shows a configuration of an underwater ultrasonic transducer according to a conventional example.

The underwater ultrasonic transducer shown in FIG.
In this configuration, the vibrator assembly 10 is covered with a castor oil 12 and a radome 14. The vibrator assembly 10 has a cylindrical shape, and has a configuration in which the vibrators 16 are arranged in a matrix on the outer peripheral surface. The surface of the vibrator 16 other than the sound wave radiating surface (the surface facing the outside of the radome 14 and transmitting and receiving the ultrasonic waves) is covered with the sound insulating material. Therefore, the vibrator 16 is provided via the castor oil 12 and the radome 14. Transmits and receives ultrasonic waves underwater.

[0007] The exterior structure of the castor oil 12 and the radome 14 is used to protect the vibrator assembly 10 and the ship from water and side pressure, and to secure the acoustic window of the vibrator 16.

[0008] That is, since the underwater ultrasonic transducer is used underwater, the water will penetrate unless it has a waterproof structure.
This will cause inundation of the ship. Therefore, the exterior of the vibrator assembly 10 needs to be provided.

Further, in water, pressure is applied to the underwater ultrasonic transducer from the side due to the flow of the water or the movement of the underwater ultrasonic transducer. If this pressure, that is, the so-called lateral pressure, is directly applied to the vibrator assembly 10, there is a possibility that the vibrator may be broken. In order to prevent such a problem, the castor oil 12, which is a liquid, is filled inside the radome 14, so that a side pressure is not applied to the vibrator assembly 10 according to Pascal's law.

It is necessary to ensure matching of the acoustic impedance between the vibrator 16 and water in order to secure necessary sensitivity and band. As a material that enables this alignment, FRP, polyurethane resin, or the like is used for the radome 14, and castor oil 12 is used as a liquid that functions as a cushioning material for lateral pressure.

[0011]

However, in such a configuration, the necessity of using the castor oil 12 increases the outer diameter and increases the weight. In other words, castor oil 12
Must be secured to some extent.

In order to solve such problems, it is necessary to improve the strength of the vibrator assembly 10 so that the vibrator assembly 10 is not easily broken even when a lateral pressure is applied. If the vibrator assembly 10 is not broken by the lateral pressure, the castor oil 12 as a buffer member for the lateral pressure becomes unnecessary, and the device can be reduced in size and weight.

From such a viewpoint, the applicant of the present application firstly
A technique has been proposed in which the vibrator assembly 10 is configured using a molded product of cork and a technique in which the caster oil 12 is abolished and the vibrator assembly 10 is covered with a resin mold (Heisei 2).
Application for the registration of a utility model dated Oct. 5, (1) “Ultrasonic vibrator assembly” and (6) Resin-molded piezoelectric vibrator assembly ”).

FIG. 10 shows an underwater ultrasonic transducer having a configuration combining both techniques. The underwater ultrasonic transducer shown in this figure has a configuration in which the transducer assembly 10 is resin-molded, as shown in FIG. That is, the resin 22 is injected from the container 20 through the injection port 18 into the molding die 17 in which the vibrator assembly 10 is disposed. The resin 22 is a polyurethane resin, an epoxy resin, or the like,
Once temporarily cured, it is removed from the mold (release),
It is cured to produce an underwater ultrasonic transducer.

By employing such a manufacturing method and structure, a small and light underwater ultrasonic transducer can be realized.

Incidentally, in such a configuration, the molding die 1
Release from 7 is essential. As means for smoothly releasing the mold and preventing the occurrence of defects, for example, a release agent is applied to the inner surface of the mold 17, the mold 17 is split, or the inner surface of the mold 17 is slightly tapered. There is a way to attach.

However, it is difficult to perform good release only by applying the release agent, and the split die has problems in terms of man-hours and costs. Further, the acoustic matching between the vibrator 16 and the water cannot be ensured by merely providing the taper. That is, the acoustic impedance is determined according to the thickness of the radome 14 and the radome 14 interposed between the vibrator 16 and water.
Is not preferable in view of the transmission / reception sensitivity and the band.

The present invention has been made to solve such a problem, and an object of the present invention is to provide a radome having a tapered surface that can maintain acoustic matching.

[0019]

In order to achieve the above object, according to the present invention, the diameter of each part of the tapered surface of the outer surface of the radome is substantially matched with the acoustic impedance of the corresponding vibrator. It is characterized by being set in a range.

[0020]

In the underwater ultrasonic transducer according to the present invention, the radome has a tapered surface, so that the mold is easily released. Further, since the diameter is limited by the acoustic impedance, acoustic performance is ensured by ensuring matching.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. Note that the same components as those of the conventional example shown in FIGS. 9 to 11 are denoted by the same reference numerals, and description thereof will be omitted.

FIG. 1 shows the configuration of an underwater ultrasonic transducer according to a first embodiment of the present invention. This example is
This is a configuration in which the vibrator assembly 10 is covered by a radome 24 having a tapered surface.

This radome is formed by a resin mold as in the second conventional example shown in FIG. That is, as shown in FIG. 2, the vibrator assembly 10 is placed in a molding die 26 in which the resin
2 are injected. As the resin 22, a polyurethane resin, an epoxy resin, or the like can be used. Resin 22
After the injection of, the underwater ultrasonic transducer is manufactured through the steps of temporary curing, release, and curing.

Also, in order for the radome 24 to have a tapered surface, the inner surface of the mold 26 must be tapered.
The tapered surface of the mold 26 is used for the radome 24 to be realized.
Is set in accordance with the tapered surface of.

FIG. 3 shows the dimensions of the tapered surface of the radome 24 to be realized by the mold 26.

In this embodiment, the outer diameters φ1, φ2, and φ3 of each part of the radome 24 are set according to the transmission / reception wavelength λ of the vibrator 16. First, the thickness t of the radome 24 corresponding to the center of the vibrator assembly 10 is set to λ / 2 because of the need for acoustic matching of the vibrator 16.
Next, the wall thicknesses of the narrowest portion (small diameter end) and the widest portion (large diameter end) of the vibrator assembly 10 are set to + 10% and −10%, respectively, based on this portion. That is, when the outer diameter of the vibrator assembly 10 is φ0, the diameters φ1, φ2, and φ of the small-diameter end, the central portion, and the large-diameter end.
3 are φ0 + 0.90 × 2t, φ0 + 2t, φ
0 + 1.10 × 2t.

When concretely considered by numerical values, φ0 = 360 m
When m and t = 25 mm, φ1 = 405 mm, φ2 = 4
10 mm and φ3 = 415 mm.

The numerical value of ± 10% in this case is:
The numerical values are set so that Q at the transmission / reception frequency of the vibrator 10 is good for any of the small-diameter end, the central portion, and the large-diameter end.

That is, as shown in FIG. 4, the region where the acoustic window at the small-diameter end of the radome 24 and the acoustic window at the large-diameter end overlap each other is made to coincide with the transmission / reception frequency of the vibrator 10. Note that Q is determined according to the acoustic impedance by a known formula.

In this way, good acoustic performance (transmission / reception band and sensitivity) can be ensured at any part of the radome 24.

Further, since the tapered surface is provided,
Demolding becomes easy. As indicated by arrows in FIG. 5, the flow of the resin 22 in the case where there is a tapered surface is divided into two vertical directions. For this reason, the central portion becomes relatively loose, and the mold release becomes easy.

FIG. 6 shows the characteristics of the underwater ultrasonic transducer according to the second embodiment of the present invention. This example is
The configuration is the same as that of the first embodiment, and the transmission and reception frequencies at the small-diameter end, the central portion, and the large-diameter end are distributed by selecting the vibrator 16.

In other words, the vibrator 16 has a certain degree of transmission / reception frequency variation as long as it is manufactured by a normal method. In manufacturing the vibrator assembly 16, the vibrator 16 having a variation is selected based on the transmission / reception frequency, and a relatively low frequency is placed on the thin small-diameter end of the radome 24 and a high frequency is placed on the thick large-diameter end of the radome 24. Place on the side.

In this manner, the same effects as in the first embodiment can be obtained.

FIG. 7 shows a configuration of an underwater ultrasonic transducer according to a third embodiment of the present invention. In the underwater ultrasonic transducer shown in this drawing, the vibrator assembly 30 has a tapered outer surface.

In this manner, as shown in FIG. 8, the transmission / reception frequency and the acoustic window can be made to match regardless of the tapered surface of the radome 24.

[0037]

[Effects of the Invention] As described above, according to the present invention,
The tapered surface of the radome facilitates release, and matching is ensured by setting the diameter of the radome by acoustic impedance, thereby ensuring acoustic performance.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a configuration of an underwater ultrasonic transducer according to a first embodiment of the present invention.

FIG. 2 is a view showing a resin molding step of the first embodiment.

FIG. 3 is a diagram illustrating dimension setting in the first embodiment.

FIG. 4 is a diagram showing characteristics of the first embodiment.

FIG. 5 is a diagram showing a flow of resin in the first embodiment.

FIG. 6 is a diagram illustrating characteristics of the underwater ultrasonic transducer according to the second embodiment of the present invention.

FIG. 7 is a perspective view showing a configuration of an underwater ultrasonic transducer according to a third embodiment of the present invention.

FIG. 8 is a diagram showing characteristics of the third embodiment.

FIG. 9 is a perspective view showing a configuration of an underwater ultrasonic transducer according to a first conventional example.

FIG. 10 is a perspective view showing a configuration of an underwater ultrasonic transducer according to a second conventional example.

FIG. 11 is a view showing a resin molding step of a second conventional example.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 vibrator assembly 16 vibrator 22 resin 24, 30 radome 26 molding die φ1, φ2, φ3 each part diameter of radome t central part thickness λ transmission / reception wavelength

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Masayoshi Tanaka 5-1-1 Shimorenjaku, Mitaka City, Tokyo Japan Radio Co., Ltd. (56) References JP-A-3-224400 (JP, A) -167794 (JP, U)

Claims (1)

(57) [Scope of request for utility model registration] 1. A vibrator assembly in which an ultrasonic vibrator is incorporated, and a vibrator assembly which is externally provided so as to prevent water from entering into the vibrator and has a resin in a mold so as to function as an acoustic window of the vibrator. And a radome formed by injecting and curing an acoustic propagation medium such as an underwater ultrasonic transducer having an outer surface of the radome whose diameter is more toward the side corresponding to the release opening of the mold. An underwater ultrasonic transducer characterized in that it is a tapered surface in which the diameter of each part is set within a range that is large and that the acoustic impedance matching with the corresponding transducer is substantially maintained.