JPH0520498U - Receiver - Google Patents

Abstract

(57) [Abstract] [Purpose] Remove the acceleration component contained in the output of the receiver,
It reduces noise and improves acoustoelectric conversion efficiency. [Structure] Piezoelectric vibrators 1 and 2 are connected in phase. The piezoelectric vibrators 1 and 2 are point-contact supported on both sides of the support housing 4 via the connecting rod 3. By being supported on both sides and connected in phase, the acceleration components generated in the piezoelectric vibrators 1 and 2 are canceled out. The piezoelectric vibrators 1 and 2 are made of a porous piezoelectric material. The specific gravity of the porous piezoelectric material is small, so that the level of the acceleration component is suppressed. Also,
Since the piezoelectric vibrators 1 and 2 are point-contact supported by the support housing 4 by the connecting rod 3, the degree of freedom of movement of the piezoelectric vibrators 1 and 2 in the radial direction of the cylinder is increased, and the acoustic-electric conversion efficiency is improved. .

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to improvement of a wave receiver having a piezoelectric body.

[0002]

[Prior Art]

 Conventionally, underwater acoustic wave receivers have been used to receive underwater sound. This is a wave receiver that receives sound propagating in water with a piezoelectric body and outputs it as an electrical signal to the outside. FIG. 3 shows a structure of a wave receiver having a structure similar to that disclosed in Japanese Patent Laid-Open No. 59-176992 related to a conventional example. In particular, FIG. 3A shows the cross section, and FIG. 3B shows the element connection.

As shown in FIG. 3A, in this conventional example, two cylindrical piezoelectric vibrators 8 and 9 are coaxially arranged, and the piezoelectric vibrator 9 on the inner side of the piezoelectric vibrators 9 and 9 blocks the sound. It is configured so that the piezoelectric vibrator 8 enclosed by the layer 10 and on the outer side is in contact with the outer layer 11. In the wave receiver having such a configuration, the piezoelectric vibrator 8 on the outer side receives the sound wave via the outer layer 11 that transmits the sound wave. The piezoelectric vibrator 8 converts the received sound wave into a voltage, and outputs the voltage from the plus and minus electrodes formed on the front and back (outside and inside of the cylinder). In FIG. 3 (b), this voltage is represented by E _s .

Further, the inner piezoelectric vibrator 9 is connected to the outer piezoelectric vibrator in a reverse phase. That is, as shown in FIG. 3B, the negative electrode of the piezoelectric vibrator 9 is short-circuited with the negative electrode of the piezoelectric vibrator 8, and the positive electrode of the piezoelectric vibrator 8 and the piezoelectric vibrator 9 are connected to each other. It is connected so as to output a voltage from between the lath electrode. The piezoelectric vibrator 9 is a vibrator for canceling the acceleration component included in the output voltage of the piezoelectric vibrator 8.

That is, this conventional example has a cable-like appearance, and when acceleration is applied in the breaking direction of the cable, the piezoelectric vibrators 8 and 9 generate a voltage Eα related to the acceleration, respectively. . However, as a result of the piezoelectric vibrators 8 and 9 being connected in reverse phase, the output voltage from the series connection becomes a voltage obtained by canceling out the acceleration voltage E _α . That is, only the voltage E _s related to reception of the sound wave is obtained.

As described above, conventionally, the voltage E _α applied to the acceleration is canceled. In general, the acceleration voltage E _α increases the noise level and deteriorates the S / N of the wave receiver. This conventional example is used in a so-called non-resonant system, that is, in a frequency band lower than the resonance point, and such suppression of acceleration sensitivity is very effective in improving S / N.

[0007]

[Problems to be solved by the device]

 However, in the conventional wave receiver having such a configuration, if the acceleration sensitivities of the two vibrators are the same or if the acceleration sensitivities of the two vibrators are different, the gain of the head amplifier is changed. I had to fine-tune and cancel the voltage related to acceleration. This is a hindrance to manufacturing, as well as having to use two types of vibrators having different sizes.

The present invention has been made to solve the above problem, and uses a transducer having the same size and the same acceleration sensitivity to cancel the voltage component due to acceleration and extract only the voltage related to the sound wave. It is an object of the present invention to provide a wave receiver that can be used.

[0009]

[Means for Solving the Problems]

 In order to achieve such an object, the present invention comprises a plurality of piezoelectric bodies formed of a perforated piezoelectric material, and a support housing in which the piezoelectric bodies are point-contact supported on both sides. Are connected in phase.

[0010]

[Action]

 In the present invention, the plurality of piezoelectric bodies are formed from a perforated piezoelectric material. The perforated piezoelectric material is, for example, a material disclosed in Japanese Patent Application Laid-Open No. 1-172281 filed by the applicant of the present application, whereby a piezoelectric body having a low specific gravity can be obtained and an acceleration component can be suppressed. To be done. Further, in the present invention, the piezoelectric body is point-contact supported on both sides of the support housing. Due to the support on both sides, acceleration components are generated in opposite phases in each piezoelectric body. Therefore, the in-phase connection of the piezoelectric bodies electrically cancels the acceleration component. Further, by supporting the point contact, the degree of freedom of movement of the piezoelectric body is increased, and the acoustoelectric conversion loss is reduced.

[0011]

【Example】

 Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows the configuration of a wave receiver according to an embodiment of the present invention. In particular, FIG. 1 (a) shows the cross section of the embodiment, and FIG. 1 (b) shows the element connection. As shown in this figure, this embodiment has two piezoelectric vibrators 1 and 2. The piezoelectric vibrators 1 and 2 have a cylindrical shape, and electrodes (not shown) are formed on the front and back (outside and inside of the cylinder). Lead wires 7 are respectively drawn from the electrodes.

The piezoelectric vibrators 1 and 2 are supported and fixed on both sides of a support housing 4 via a connecting rod 3. The connecting rod 3 has a function of supporting the piezoelectric vibrators 1 and 2 on the supporting housing 4 in a point contact manner. Further, the inside of the piezoelectric vibrators 1 and 2 is filled with foamed rubber 5 having closed cells, and the entire wave receiver is molded with urethane rubber 6.

Further, in this embodiment, the piezoelectric vibrators 1 and 2 are connected in phase as shown in FIG. That is, the voltage generated in the piezoelectric vibrator 1 and the voltage generated in the piezoelectric vibrator 2 are connected so as to be added. Further, the material forming the piezoelectric vibrators 1 and 2 in this embodiment is a so-called porous piezoelectric material. As the piezoelectric material, lead zirconate titanate (PZT) has been conventionally known, but its specific gravity is as large as about 7.4. However, since the voltage generated by acceleration is proportional to the specific gravity of the piezoelectric material, the unnecessary voltage generated by the acceleration applied to the entire receiver is higher as the specific gravity is higher. The porous piezoelectric material used in this example is disclosed in the above-mentioned JP-A-1-172281, and its specific gravity is, for example, about 4.6.

FIG. 2 shows a manufacturing process of this porous piezoelectric material. The piezoelectric vibrators 1 and 2 formed of a porous piezoelectric material are formed by mixing a piezoelectric material 100 such as PZT and a high molecular polymer 101 such as methacrylic resin (102) and molding the mixture into a cylindrical shape. (103), and further by firing at a predetermined temperature (104). Further, in order to extract the voltage from the piezoelectric vibrators 100 and 101, it is necessary to print an electrode on the surface thereof. After performing the baking 105, polarization (106) is performed in a predetermined direction to obtain piezoelectric vibrators 1 and 2 formed of a porous piezoelectric material having desired characteristics. For example, when the mixing ratio of the high molecular polymer 101 to the PZT 100 is set to 15 wt%, the porosity (porosity) caused by the high molecular polymer 101 being burnt out by the baking 104 becomes 41%. Thus, piezoelectric vibrators 1 and 2 made of a porous piezoelectric material having a specific gravity of 4.6 can be obtained.

This embodiment has the configuration as described above. In this embodiment, when a sound wave is propagated and received from the water to the piezoelectric vibrators 1 and 2 through the urethane rubber 6, the voltage related to the output from the piezoelectric vibrators 1 and 2 is shown in FIG. 1 (b). The signals are added by the connected wiring and output as a receiver signal. This is because underwater sound waves propagate isobarically.

The piezoelectric vibrators 1 and 2 are fixed to both sides of the support housing 4 by a predetermined number (for example, three) of connecting rods 3. Therefore, the radial movement of the cylinders of the piezoelectric vibrators 1 and 2 is easy and the underwater sound wave can be efficiently converted into an electric signal.

An external acceleration component (for example, vibration) applied to this wave receiver is applied to the support housing 4 and transmitted to the piezoelectric vibrators 1 and 2 via the connecting rod 3. When the support housing 4 moves upward, a compression force is applied to the piezoelectric vibrator 1 and an extension force is applied to the piezoelectric vibrator 2 due to this acceleration. On the contrary, when the support housing is moved downward, the piezoelectric vibrator 2 receives a stretching force and the piezoelectric vibrator 1 receives a compressive force. The voltage generated by the acceleration applied in this way, that is, the acceleration signal component is generated in the opposite phase between the piezoelectric vibrators 1 and 2. The acceleration-related voltages thus generated in opposite phases are electrically canceled by the connection shown in FIG. 1 (b). Therefore, in principle, the receiver component does not include the component related to acceleration.

However, although canceled out in principle in this way, a voltage related to acceleration may remain due to element characteristics, variations in manufacturing, and the like. On the other hand, the voltage generated by the acceleration is proportional to the mass of the piezoelectric vibrators 1 and 2, and therefore is sufficiently suppressed in the piezoelectric vibrators 1 and 2 formed of a porous piezoelectric material having a smaller specific gravity than the conventional one. Only the acceleration component of the specified level is output. Therefore, according to the present embodiment, the influence of the acceleration component is eliminated in terms of the material of the piezoelectric vibrators 1 and 2, the supporting structure of the piezoelectric vibrators 1 and 2, and the connection. , Unnecessary voltage generated by acceleration is reduced. Further, since the piezoelectric vibrators 1 and 2 are attached to the support housing 4 by the connecting rod 3, the efficiency of converting underwater acoustic waves into electric signals (conversion efficiency) becomes high. The number of connecting rods 3 need not be three.

[0020]

[Effect of the device]

 As described above, according to the present invention, the piezoelectric body is formed of a perforated piezoelectric material, and the piezoelectric body is supported so as to be in point contact support on both sides of the support housing. Since the connection is made, a receiver with less noise that can remove the acceleration component in terms of material, structure, and wiring can be obtained. In addition, the point contact support increases the degree of freedom of movement of the piezoelectric body and improves the conversion efficiency of sound waves into electric signals.

[Brief description of drawings]

1A and 1B are diagrams showing a configuration of a wave receiver according to an embodiment of the present invention, in which FIG. 1A is a sectional view and FIG. 1B is an element connection diagram.

FIG. 2 is a flowchart showing a manufacturing process of a porous piezoelectric material.

3A and 3B are diagrams showing a configuration of a wave receiver according to a conventional example, wherein FIG. 3A is a sectional view and FIG. 3B is an element connection diagram.

[Explanation of symbols]

 1, 2 Piezoelectric vibrator 3 Connecting rod 4 Support housing

Claims (1)

[Scope of utility model registration request] 1. A plurality of piezoelectric bodies formed of a perforated piezoelectric material, and a support casing in which the piezoelectric bodies are supported in point contact on both sides, wherein the piezoelectric bodies are connected in phase. Receiver.