JPS61251399A - Manufacture of ultrasonic wave transmitter-receiver - Google Patents

Abstract

PURPOSE:To obtain a deep depth ultrasonic wave transmitter and receiver by specifying the thickness of a sheet like intermediate medium and a metal plate with respect to a wave length an internal acoustic wave, providing the metal plate on a rear surface of an oscillating member through the intermediate medium and filling a water proof mold agent equal to the intermediate medium into a circumference of the oscillating member. CONSTITUTION:A metal plate 9 is groove worked and formed so as to have the thickness of 1/9-14/34 of a wave length of an internal acoustic wave and an intermediate medium 8 made of a sheet like rubber material is formed and the medium 8 is bonded to a groove bottom section of a metal plate 9 by an instantaneous bonding agent. Then, on the medium 8, an oscillating member 5 connecting a cable 7 is mounted, and on the circumference thereof, a water- proof mold material of the same material as the medium 8 is filled, the mold material 6 is thermoset to fix the oscillating member 5 to the metal plate 9 and produce an ultrasonic wave transmitter and receiver. In this manner, a deep depth ultrasonic wave transmitter and receiver of high reliability can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of manufacturing an ultrasonic receiver used under high water pressure.

[Conventional technology]

The structure of a conventional transducer array will be explained based on FIG. In FIG. 2, reference numeral 1 is an ultrasonic transducer (hereinafter referred to as a transducer), 2 is Kirk rubber, 3 is a cable, and 4 is a rubber material, and is constructed as described above.

First, in order to operate as a transducer, a voltage is applied to the vibrator 1 at a constant frequency to cause it to vibrate. Then, a sound wave is emitted from the front of the opening of the vibrator 1 that is not surrounded by the Kirk rubber 2. At this time, the sound waves are radiated with a certain directivity. The emitted sound waves propagate through water, hit an object, are reflected, and return to the vibrator 1. Here, when a sound wave is incident on the vibrator 1, the sound wave is not incident on the side surface of the vibrator 1 because it is surrounded by the Kirk rubber 2. Therefore, since the vibration is small, the voltage output is also small.

The reason why the reception sensitivity is high for sound incident from the front and low reception sensitivity for sound incident from the rear is that the characteristic acoustic impedance of the Kirk rubber 2 is resistant to acoustic media such as water. This is achieved because it is sufficiently low.

As described above, Kirk rubber 2 has a low specific acoustic impedance, which is equivalent to a low Young's modulus.

[Problem that the invention seeks to solve]

Therefore, in the conventional example using Kirk rubber having such a small puffer ratio, there is a problem that the Kirk rubber loses its sound insulating properties in deep oceans because the Kirk rubber is compressed by hydrostatic pressure.

In addition, when Kirk rubber is compressed and deformed,
Large strains may be applied to other components, resulting in cracks in the rubber material and loss of waterproof properties. Therefore, the water pressure resistance of the conventional example shown in Figure 2 is 100-2.
There is a problem that the limit is about 00m.

In the above explanation, the operation and problems as a wave receiver have been described, but it is a matter of course that similar problems will occur when operating as a wave transmitter due to the principle of reversibility of a wave transmitter/receiver.

The present invention has been made in order to solve the above-mentioned problem, and its purpose is to solve the above-mentioned problem.
It is an object of the present invention to provide a method for manufacturing an ultrasonic transducer, the solution of which is disclosed in No. 34, and to make it possible to obtain high reliability even in deep oceans.

[Means for solving problems]

In order to achieve the above object, the present invention provides a packing structure in which a metal plate is placed on the rear surface of a vibrator that vibrates through thickness or longitudinally, or a dicing type vibrator, etc., with an intermediate medium made of a rubber material interposed therebetween. The intermediate medium and the metal plate each have a thickness of 1/9 to 1 of the wavelength of the internal sound wave.
It is characterized by being 4/36.

[Effect]

In the present invention having the above characteristics, the thickness of the sheet-like intermediate medium and the metal plate is 14 to 14/(6) of the wavelength of the internal sound wave.
A metal plate is provided on the rear surface of the vibrator, etc. with the intermediate medium interposed in between, and a waterproof molding material of the same quality as the intermediate medium is poured around the vibrator, etc., and this waterproof molding material is heated and hardened to form the vibrator. is fixed to the metal plate.

〔Example〕

A first embodiment of the present invention will be described below with reference to FIGS. 1, 3, and 4.

FIG. 1 is a sectional view showing a first embodiment of an ultrasonic transducer according to the present invention. In FIG. 1, 5 is a vibrator, 6 is a waterproof molding material made of rubber or the like, 7 is a cable, 8 is an intermediate medium made of a sheet-like rubber material, and 9 is a metal plate. The metal plate 9 is provided on the rear surface of the vibrator 1 with the intermediate medium 8 interposed therebetween, and the thickness of the metal plate 9 and the intermediate medium 8 is 1/9 to 14/of the wavelength of the internal sound wave, respectively. 3
Limited to 6. Incidentally, the waterproof Cfuuu;l' material 6 and the intermediate medium 8 are made of the same material.

Next, a method of manufacturing an ultrasonic transducer having such a configuration will be explained. First, each thickness is 1/9 of the wavelength of the internal sound wave.
The metal plate 9 is formed by groove processing so as to have a diameter of 14/36, and the intermediate medium 8 is formed, and this intermediate medium 8 is attached to the bottom of the groove of the metal plate 9 with a dianoacrylate instant adhesive as shown in FIG. Glue as shown.

Then, the vibrator 5 to which the cable 7 is connected is placed on the intermediate medium 8, and a liquid waterproof molding material 6 made of the same material as the intermediate medium 8 is poured around it, and the waterproof molding material 6 is heated to harden. is fixed to a metal plate 9 to manufacture an ultrasonic transducer as shown in FIG.

The operation of the ultrasonic transducer manufactured in this way will be explained based on FIGS. 3 and 4.

FIG. 3 is an explanatory diagram of the operation of the ultrasonic transducer shown in FIG. 1, and FIG. 4 is a diagram showing the front-back ratio FBR of incident sound from the front and rear as a function of frequency. When a sound wave is incident from behind as shown by the arrow in FIG. 3, the sound wave B1 reflected at the boundary C between the waterproof mold material 6 and the metal plate 9 and the boundary
When the metal plate 9 has a thickness of 1/4 wavelength, the sound wave B2 that has passed through and reflected at the boundary between the metal plate 9 and the intermediate medium 8 becomes in phase and synthesized as a strong reflected wave.

On the other hand, when the intermediate medium 8 has a thickness of 1/4 wavelength, it is a boundary. ,
The sound wave B5 that has passed through b, reflected at the boundary a between the intermediate medium 8 and the vibrator 5, and has already been re-reflected at the boundary, and the sound wave BII that has passed through the boundaries c and b and reached the boundary a, are at the boundary a. They are in opposite phases and cancel each other out. Therefore, the vibration of the vibrator 5 due to the sound incident from behind becomes small, and therefore the wave reception sensitivity is also low.

The above explanation is qualitative, and since transmission and reflection are actually performed multiple times at the boundaries a, b, and c, the phenomenon is a little more complicated.

According to the inventor's analysis using a transmission line model,
The front-to-back ratio FBR is equal to the open transmission coefficient due to sound incident from the rear. However, it is necessary that . zo: natural acoustic impedance of the vibrator 5, Rw: characteristic acoustic impedance of the sound field medium, zB: characteristic acoustic impedance when looking backward from boundary a, kO: wave number of the vibrator 5, lO: thickness of the vibrator 1 .

The above conditions are satisfied at most frequencies in the first embodiment.

In the ultrasonic transducer shown in FIG. 1, an intermediate medium 8 having 174 wavelengths at a reference frequency and 1/4
Packing has a two-layer structure consisting of a metal plate 9 having a wavelength.

Here, when stainless steel is used as the metal plate 9, the open transmission coefficient ratio FBR is as follows.

Therefore, if the front/rear ratio FBR is expressed as a function of frequency, then
The result is as shown in FIG. In Figure 4, the front/rear ratio FBR
is 20 dB or more in the range of f 4 14 fQ 9 9 , which corresponds to 1/9 wavelength to 14A6 wavelength.

Next, a second embodiment of the present invention will be described based on FIG.

FIG. 5 is a perspective view showing a second embodiment of the method for manufacturing an ultrasonic transducer according to the present invention. In FIG. 5, 10 is a longitudinally vibrating vibrator, 11 is a waterproof shield material made of a rubber material, etc., 12 is an intermediate medium made of a sheet-like rubber material, and 13 is a metal plate. The metal plate 13 is provided on the rear surface of the vibrator 10 with the intermediate medium 12 interposed therebetween, and the thickness of the metal plate 13 and the intermediate medium 12 is 1/9 to 14/36 of the wavelength of the internal sound wave, respectively. Limited.

14 is a signal line, 15 is a housing case, 16 is a covered cylindrical boot, 17 is oil, and 1B is a cylindrical housing, which has an electronic circuit 19 built inside, and terminals 20.
Terminal plates 22 and 23 provided with terminals 21 are attached through O-rings 24 so as to maintain watertightness, and grooves 25 for attaching the boots 16 are carved on the outer periphery of one end. 26 is the band, 2
7 is a fixing 7 lange attached to the other end of the housing 18;
It is attached as appropriate when it is fixed to another structure, for example, one side of a submersible, or when connected to a 7-lunge of a high water pressure multicore cable. The terminal plates 22 and 23 are made of a hermetic seal having excellent watertightness.

Next, a method of manufacturing the ultrasonic transducer will be explained.

First, a transducer array is formed by arranging the transducers 10 in a row, and the intermediate medium 12 is interposed on the rear surface of the transducer array, and the metal plate 13 is packed with the intermediary medium 12 interposed therebetween. A liquid waterproof shielding material 11 is poured through the tube 15 and hardened and fixed by heating.

Then, the signal line 14 is connected to a terminal plate 22 attached to the housing 18. After that, cover the housing case 15 with oil.
The boot 16 is placed in the mounting groove 25 of the casing 18, and is fastened to the casing 18 with a band 26.

With this, the boot 1 can be connected to the terminal board 22 attached to the housing 18.
6 is sealed to prevent seawater etc. from mixing with the oil 17 in the boot 16.

The ultrasonic transducer manufactured in this way has its signal line 14 housed together with the transducer array in the oil-filled boot 16, so even if it is lowered into the sea under high water pressure, the compression difference between each component will be maintained. Therefore, the tension caused by the signal line 14 is not applied to the signal line 14, and troubles such as disconnection do not occur.

In addition, the terminal plates 22 and 23 provided at both ends of the housing 18 connect the signal wire 14 on the boot 16 side, the signal wire on the other structure side (not shown) connected to the fixing 7 langes 2T, and the signals inside the housing 18. Since the lines are completely isolated, even under high water pressure, each signal line 14 etc. can be lowered into the sea without any excessive force being applied.

Although the electronic circuit 19 is provided in this embodiment, if the electronic circuit 19 is not required, it may be directly connected to the terminal plates 22 and 23 by a signal line.

〔Effect of the invention〕

As mentioned above, according to the ultrasonic transducer according to the present invention,
The thickness of the sheet-like intermediate medium and the metal plate are respectively formed to be 1/9 to 14/36 of the wavelength of the internal ultrasonic wave, and the metal plate is provided on the rear surface of the vibrator etc. with the intermediate medium interposed therebetween. By pouring a waterproof molding material of the same quality around the vibrator, etc., and curing the waterproof molding material by heating to fix the vibrator to the metal plate, the following effects are achieved.

That is, each packing layer of the vibrator is 1/9 ~
Because it uses an intermediate medium and a metal plate with a thickness of 14/a6 wavelength, the front-to-back ratio of sensitivity can be more than 20 dB, and the front-to-back ratio does not deteriorate even at a depth of 1,500 m, and the waterproof mold Since no cracks occur in the material, it is possible to obtain a highly reliable ultrasonic transducer for deep use.

Furthermore, since the dimensions of the intermediate medium can be thoroughly inspected before assembly, accurate dimensions can be maintained, and since the intermediate medium can be bonded to a metal plate using a cyanoacrylate instant adhesive, etc. This has the effect of making the layer thickness negligible.

In addition, after installing the transducer, a waterproof shielding material of the same quality as the sheet-like intermediate medium is poured around it, so the waterproofing shielding material is spread to every corner, leaving air bubbles inside the ultrasonic transducer and deteriorating its performance. There's no need to. In other words, the vibrator needs to be surrounded by a rubber material, but by interposing an intermediate medium in advance, it is effective to prevent bubbles from forming on the rear surface of the vibrator.

Moreover, if the present invention is applied to the second embodiment, the same effects as those of the first embodiment can be achieved, and the performance can be sufficiently maintained even in applications under high water pressure.

[Brief explanation of drawings]

Fig. 1 is a sectional view of the first embodiment of the present invention, Fig. 2 is a sectional view of the conventional example, Fig. 3 is an explanatory diagram of the operation of Fig. 1, and Fig. 4 shows the front-rear ratio FBR as a function of frequency. FIG. 5 is a perspective view showing a second embodiment of the present invention. 5.10... Vibrator 6, 11... Waterproof shield material 7... Cable 8, 12... Intermediate medium 9, 13
...Metal plate 14...Signal line 15...Housing case 16...Boot 1T...Oil 18...
Cross-sectional view of the conventional example of the casing 2 Ultrasonic transducer manufacturing method 3, relationship with the case of the person making the amendment Patent applicant representative Nankai Hashimoto 4, agent 7, content of amendment 1, “Ultrasonic "Receiver" is corrected to "Ultrasonic transducer". 2. "Dianoac" in the second line of page 6 of the specification is amended to "cyanoac". 3. Formula 4 on page 6, line 17 of the specification, and "need to deteriorate, etc." on page 13, line 2 of the specification, are corrected to "worry about deterioration, etc." 5. Delete "essential" in the third line of page 13 of the specification.

Claims (1)

[Claims] 1. A packing layer having a structure in which a metal plate is placed on the rear surface of an ultrasonic vibrator or a dicing type vibrator, etc. that performs thickness vibration or longitudinal vibration, with an intermediate medium made of a rubber material interposed therebetween. In an ultrasonic transducer in which the thickness of the intermediate medium and the metal plate are respectively 1/9 to 14/36 of the wavelength of the internal sound wave, (a) the thickness of the sheet-like intermediate medium and the metal plate are respectively (b) A metal plate is provided on the rear surface of the vibrator etc. with the intermediate medium interposed in between. (c) A waterproof molding material of the same quality as the intermediate medium is provided. An ultrasonic transducer characterized in that the waterproof molding material is poured around a vibrator, etc., and (d) this waterproof molding material is heated and hardened to fix the vibrator to a metal plate.