JPH11146476A - Vibration source for echo sounder transmitter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide satisfactory acoustic radiation efficiency and to improve the degree of freedom in submarine use. SOLUTION: This vibration source is composed of two inner and outer piezoelectric vibrators 5 and 6 respectively having mutually perpendicular polarizing directions, and the piezoelectric vibrator 5 located inside between both these piezoelectric vibrators 5 and 6 has a piezoelectric constant and Poisson ratio larger than that of the piezoelectric vibrator 6 located outside and is formed from the piezoelectric vibrator having a polarizing direction perpendicular with the non-adhesive plane of the vibrator.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a vibration source for a transmitter suitable for use in an electroacoustic transducer that emits sound waves into water.

[0002]

2. Description of the Related Art In general, there is known an electroacoustic transducer provided with a vibration source for a transmitter having a piezoelectric vibrator made of, for example, a zirconia acid / lead titanate piezoelectric material.
As the piezoelectric vibrator of the vibration source for the transmitter, for example, as shown in FIG. 6, a piezoelectric vibrator 52 with a lead wire 51 having a relatively large piezoelectric constant (d33) and Poisson's ratio is used.

In such a vibration source for a transmitter, when a voltage is applied to a piezoelectric vibrator 52 from a lead wire 51,
As shown by a two-dot chain line in the same drawing, it expands in the vertical direction and contracts in the horizontal direction. For this reason, a vibration sound having a phase opposite to the phase of the vibration sound radiated in the vertical direction of the piezoelectric vibrator 52 is radiated to both sides, and the sound radiation efficiency is poor.

Further, such a vibration source for a transmitter includes a piezoelectric vibrator having a relatively small piezoelectric constant (d31) and Poisson's ratio. It is conceivable to prevent radiation, but in this case, the sound radiated in the vertical direction is also small, and the sound radiation efficiency is poor as in the case of a piezoelectric vibrator having a relatively large piezoelectric constant (d33) and Poisson's ratio.

Therefore, in order to obtain good sound radiation efficiency, conventionally, FIGS. 7A and 7B and FIGS.
A transmitter vibration source as shown in FIG.
These vibration sources for the transmitter will be described with reference to FIG.
First, the vibration source for the transmitter shown in FIGS. 7A and 7B will be described. In FIG. 7, the vibration source for the transmitter indicated by reference numeral 61 includes a piezoelectric vibrator 62 and a metal cover 63. The piezoelectric vibrator 62 is formed entirely of a columnar piezoelectric vibrator.

The metal cover 63 is formed of a cylindrical body having inner flanges 63a and 63b on both open end faces and opening in both axial directions, and is attached to the outer peripheral surface of the piezoelectric vibrator 62. A sound absorbing air layer 64 is formed between the inner peripheral surface of the metal cover 63 and the outer peripheral surface of the piezoelectric vibrator 62, or a sound absorbing (blocking) member such as cork (not shown). Is filled.

Next, the vibration source for the transmitter shown in FIGS. 8 (a) and 8 (b) will be described.
1 includes a piezoelectric vibrator 72 and a metal cover 73, similarly to the transmitter vibration source 61 shown in FIGS. 7A and 7B. The piezoelectric vibrator 72 is formed of a piezoelectric vibrator having a horizontally long rectangular cross-sectional shape as a whole.

The metal cover 73 is composed of two cover elements 73a and 73b having a U-shaped cross section and having a vertically long outer dimension.
The cover elements 73a and 73b are bonded to both side surfaces of the piezoelectric vibrator 72. The lateral dimensions of each of the cover elements 73 a and 73 b are set to be sufficiently smaller than the lateral dimensions of the piezoelectric vibrator 72, and the vertical dimensions thereof are set to be the same as the vertical dimensions of the piezoelectric vibrator 72.
A sound absorbing air layer 74 is formed between each of the cover elements 73a and 73b and the piezoelectric vibrator 72, or a sound absorbing (blocking) member (not shown) such as cork is filled. I have.

[0009]

However, in a conventional vibration source for a transmitter, air layers 64 and 74 or a member for acoustic absorption (shown in the drawing) are provided between the metal covers 63 and 73 and the piezoelectric vibrators 62 and 72. In the case where the water depth position is used at a considerably deep position, if the stress generated by water pressure increases, the metal covers 63, 73, etc. are damaged, and the degree of freedom in underwater use is reduced. There was a problem.

In a conventional vibration source for a transmitter,
Since a single piezoelectric vibrator is used, when the piezoelectric constant and Poisson's ratio are relatively large, vibration sounds having opposite phases are emitted from the piezoelectric vibrator, while the piezoelectric constant and Poisson's ratio are relatively small In such a case, only a small vibration sound is emitted from a predetermined vibration surface, and there is also a problem that good sound radiation efficiency cannot be obtained.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a vibration source for a transmitter capable of obtaining a degree of freedom in underwater use and obtaining good acoustic radiation efficiency. And

[0012]

According to a first aspect of the present invention, there is provided a vibration source for a transmitter, wherein the vibration sources are respectively bonded inside and outside of each other and can be applied independently of each other. And two piezoelectric vibrators vibrated by the piezoelectric vibrators, each of which comprises a piezoelectric vibrator having a polarization direction perpendicular to each other. Is formed by a piezoelectric vibrator having a piezoelectric constant and a Poisson's ratio larger than that of the sub-piezoelectric vibrator located in the direction indicated by the arrow and having a polarization direction perpendicular to the vibrator non-adhesive surface. Therefore, when an in-phase electric signal is applied to the two main and sub piezoelectric vibrators to vibrate the main piezoelectric vibrator in a direction perpendicular to the non-adhesive surface of the vibrator, the main vibrator vibrates according to the Poisson's ratio. While contracting in the direction of the non-bonding surface, the sub-piezoelectric vibrator expands to compensate for the contraction of the main piezoelectric vibrator, and contraction of the main piezoelectric vibrator in the direction of the non-bonding surface of the vibrator disappears apparently.

According to a second aspect of the present invention, in the vibration source for a transmitter according to the first aspect, the main piezoelectric vibrator is formed by a cylindrical member, and the sub-piezoelectric vibrator is formed by a cylindrical member opened in both axial directions. There is a configuration. Therefore, when the same phase electric signal is applied to the two main and sub piezoelectric vibrators to vibrate the main piezoelectric vibrator in the vibrator axial direction, the main piezoelectric vibrator contracts in the vibrator radial direction according to the Poisson's ratio. At the same time, the sub piezoelectric vibrator extends so as to compensate for the contraction of the main piezoelectric vibrator, so that the main piezoelectric vibrator does not apparently contract in the vibrator radial direction.

According to a third aspect of the present invention, in the vibration source for a transmitter according to the second aspect, the auxiliary piezoelectric vibrator includes a plurality of vibrator elements arranged in parallel in a circumferential direction. Therefore, when an electric signal having the same phase is applied to the two main and sub piezoelectric vibrators to vibrate each vibrator element in a direction perpendicular to the vibrator non-adhesive surface, each vibrator element is vibrated according to the Poisson's ratio. While contracting in the direction of the non-bonding surface, the sub-piezoelectric vibrator extends to compensate for the contraction of each vibrator element, and contraction in the vibrator non-bonding surface direction in each vibrator element is apparently eliminated.

According to a fourth aspect of the present invention, in the vibration source for a transmitter according to the first aspect, the main piezoelectric vibrator is formed by a single rectangular member, and the sub piezoelectric vibrator sandwiches the main piezoelectric vibrator. This is a configuration formed by two square members. Therefore, when an in-phase electric signal is applied to the two main and sub piezoelectric vibrators to vibrate the main piezoelectric vibrator in the vibrator thickness direction, the main piezoelectric vibrator contracts in the vibrator width direction according to the Poisson's ratio. At the same time, the sub piezoelectric vibrator extends so as to compensate for the contraction of the main piezoelectric vibrator, and the main piezoelectric vibrator does not apparently contract in the vibrator width direction.

According to a fifth aspect of the present invention, in the vibration source for a transmitter according to the fourth aspect, the main piezoelectric vibrator comprises a number of vibrating elements arranged in parallel in a direction perpendicular to the polarization direction. Therefore, when the same phase electric signal is applied to the two main and sub piezoelectric vibrators to vibrate each vibrator element in the polarization direction, each vibrator element contracts in a direction perpendicular to the polarization direction according to the Poisson's ratio. At the same time, the sub-piezoelectric vibrator expands to compensate for the contraction of each vibrator element, and the contraction of each vibrator element in the direction perpendicular to the polarization direction is apparently eliminated.

According to a sixth aspect of the present invention, in the vibration source for a transmitter according to any one of the first to fifth aspects, each piezoelectric vibrator is a piezoelectric vibrator of an acoustic transducer.
Therefore, when an in-phase electric signal is applied to the two main and sub piezoelectric vibrators in the acoustic transducer to cause the main piezoelectric vibrator to vibrate in a direction perpendicular to the non-adhesive surface of the vibrator, the main piezoelectric vibrator responds to the Poisson's ratio. The vibrator contracts in the direction of the non-adhesive surface of the vibrator, and the auxiliary piezoelectric vibrator extends so as to compensate for the contraction of the main piezoelectric vibrator, so that the contraction of the main piezoelectric vibrator in the non-adherent surface of the vibrator disappears.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described.
This will be described with reference to the drawings. 1A and 1B are an external perspective view and a bb local sectional view showing an example of use of a vibration source for a transmitter according to a first embodiment of the present invention, and FIG. It is sectional drawing which shows the vibration source for transmitters concerning embodiment. In FIG. 1, the electroacoustic transducer denoted by reference numeral 1 includes a transmitter vibration source 2, a baffle table 3, and a case 4. The transmitter vibration source 2 has piezoelectric vibrators 5 and 6 and lead wires 7 and 8.

The piezoelectric vibrator 5 is composed of a columnar main piezoelectric vibrator and is adhered to the upper surface of the baffle table 3. The piezoelectric vibrator 5 is entirely polarized in the axial direction (FIG. 2).
, And has a relatively large piezoelectric constant (d33) and Poisson's ratio, for example, a zirconate / lead titanate piezoelectric material (“N-6 material”).

The piezoelectric vibrator 6 is composed of a cylindrical auxiliary piezoelectric vibrator that opens in both axial directions, and is bonded to the upper surface of the baffle table 3 and the outer peripheral surface of the piezoelectric vibrator 5. The piezoelectric vibrator 6 has a polarization direction in the radial direction as a whole (the direction of arrow b in FIG. 2), and has a piezoelectric constant (d33) and a Poisson ratio smaller than the piezoelectric constant and Poisson's ratio of the piezoelectric vibrator 5, for example. Lead titanate-based piezoelectric materials ("N-2
200 materials).

The lead 7 comprises two leads,
The piezoelectric vibrator 5 is connected to upper and lower end faces (end faces in the axial direction). The lead wire 8 is composed of two lead wires and is connected to each of the inner and outer peripheral surfaces of the piezoelectric vibrator 6. Thus, an electric signal is applied to each of the piezoelectric vibrators 5 and 6 independently of each of the lead wires 7 and 8.

The baffle table 3 is entirely formed of a plane circular metal plate such as aluminum. Thus, downward emission of the vibration sound from the transmitter vibration source 2 is prevented.

The case 4 is disposed on the upper surface of the baffle base 3 and is covered by the two piezoelectric vibrators 5 and 6, and is entirely formed by a headed cylinder made of a synthetic resin such as urethane. . Thereby, the watertightness of the case 4 is maintained, and both the piezoelectric vibrators 5 and 6 and a part of the lead wires 7 and 8 are protected.

Next, the operation of the piezoelectric vibrator at the time of acoustic radiation of the electroacoustic transducer configured as described above will be described with reference to FIG.
This will be described with reference to (a) and (b). FIGS. 3A and 3B are cross-sectional views showing a state before and after vibration of the piezoelectric vibrator in the vibration source for a transmitter according to the first embodiment of the present invention. That is, from the state before the vibration shown in FIG. 6A, an electric signal having the same longitudinal mode vibration is applied to the piezoelectric vibrators 5 and 6 to move the piezoelectric vibrator 5 in a direction perpendicular to the vibrator non-adhesion surface ( When the piezoelectric vibrator 6 is vibrated in the direction of the vibrator non-adhesive surface (radial direction),
According to the Poisson's ratio, the piezoelectric vibrator 5 has a radial dimension D1a in the direction of the vibrator non-adhesive surface (radial direction) as shown in FIG.
To the radial dimension D1b, and the radial dimension D2 so that the piezoelectric vibrator 6 compensates for the contraction of the piezoelectric vibrator 5.
a to a radial dimension D2b.

At this time, since the voltage applied to each of the piezoelectric vibrators 5 and 6 is controlled, the radial dimension (D1a + 2 × D2a) of the entire piezoelectric vibrator (vibration source for a transmitter) and the vibration time The direction dimension (D1b + 2 × D2b) is the same dimension.

It should be noted that, in FIGS.
Symbol D represents the radial dimension of the vibration source 2 for the transmitter (the piezoelectric vibrator 5).
The sum of the radial dimension D1a before vibration D1a and the radial dimension 2 × D2a before vibration of the piezoelectric vibrator 6, or the radial dimension D1b of the piezoelectric vibrator 5 during vibration and the radial dimension 2 of the piezoelectric vibrator 6 during vibration 2 × D2b).

Therefore, in this embodiment, since the radial contraction of the transmitter vibration source 2 is apparently eliminated, it is possible to suppress the radial vibration of the transmitter vibration source 2 and obtain a good acoustic radiation efficiency. it can. In this case, the transmitter vibration source 2
The voltage and phase applied to each of the piezoelectric vibrators 5 and 6 were controlled in order to suppress the radial vibration of the piezoelectric vibrator 5.
May be changed in the radial direction.

Further, in the present embodiment, cork or the like conventionally required for obtaining good acoustic radiation efficiency is not required, so that it can be used even in a position where the water depth is considerably deep, and the degree of freedom in use can be improved. Can be enhanced.

Further, in the present embodiment, since the vibration (radial vibration) in the transverse mode is reduced, the sound radiating surface becomes a uniform vibration surface only on the piezoelectric vibrator 5 due to the baffle effect. Can be obtained.

In the present embodiment, the case where the piezoelectric vibrator 6 is formed of a cylindrical body that opens in both directions of the axis has been described. It works.

Next, a second embodiment of the present invention will be described with reference to FIG.
This will be described with reference to (a) and (b). 4A and 4B are an external perspective view and an bb cross-sectional view showing an example of use of a vibration source for a transmitter according to a second embodiment of the present invention.
In the figure, an electroacoustic transducer denoted by reference numeral 11 includes a vibration source 12 for a transmitter, a baffle table 13 and a case 14. The transmitter vibration source 12 includes piezoelectric vibrators 15 and 1.
6 and lead wires 17 and 18.

The piezoelectric vibrator 15 is composed of a square main piezoelectric vibrator, and is bonded to the upper surface of the baffle table 13. The piezoelectric vibrator 15 has a polarization direction which is perpendicular to the vibrator non-bonding surface and has a relatively large piezoelectric constant (d33) and Poisson's ratio.
It is formed of a lead titanate-based piezoelectric material (“N-6 material”).

The piezoelectric vibrator 16 is composed of two rectangular sub-piezoelectric vibrators, each of which is bonded to the upper surface of the baffle table 13 and to each side surface of the piezoelectric vibrator 15. The piezoelectric vibrator 6 has, for example, a lead titanate-based material having a piezoelectric direction (d31) and a Poisson ratio smaller than the piezoelectric constant and the Poisson ratio of the piezoelectric vibrator 15 as a whole, having a polarization direction in the direction of the non-adhesive surface of the vibrator. Piezoelectric material ("N-2200 material")
Is formed by

The lead wire 17 is composed of two lead wires and is connected to the upper and lower end faces of the piezoelectric vibrator 15. The lead wires 18 include two pairs of lead wires, and are connected to the inner and outer surfaces of each piezoelectric vibrator 16. As a result, electric signals are applied to the piezoelectric vibrators 15 and 16 by the respective lead wires 17 and 18.
Is applied independently of the

The entire baffle table 13 is formed of a flat rectangular metal plate such as aluminum. As a result, downward emission of the vibration sound from the transmitter vibration source 12 is prevented.

The case 14 is disposed on the upper surface of the baffle table 13 and is covered by the two piezoelectric vibrators 15 and 16, and is formed entirely of a headed box made of synthetic resin such as urethane. . Thereby, the water tightness of the inside 14 of the case is maintained, and both the piezoelectric vibrators 15 and 16 and the lead wires 17 and 18 are protected.

In the electroacoustic transducer configured as described above, the contraction of the transmitter vibration source 12 in the direction of the non-adhesive surface of the transmitter during the sound radiation is apparently eliminated.
As in the first embodiment, it is possible to obtain a good acoustic radiation efficiency by suppressing the vibration in the direction of the non-adhesive surface of the vibrator 2 and to increase the degree of freedom in use.

Further, in the present embodiment, as in the first embodiment, the vibration in the transverse mode (vibration in the direction of the non-adhesion surface of the vibrator) is reduced, so that good directivity in acoustic radiation can be obtained. .

In this embodiment, the case where the piezoelectric vibrator is constituted by a single piezoelectric vibrator has been described.
The present invention is not limited to this.
As shown in (a) and (b), a large number of vibrating elements 21 in which the piezoelectric vibrators 21 are arranged in parallel in a direction perpendicular to the polarization direction.
The same effects as those of the embodiment can be obtained even with a.

The material of the piezoelectric vibrator according to the present invention is not limited to the above-described embodiment.

[0041]

As described above, according to the present invention, the piezoelectric vibrators each having a polarization direction perpendicular to each other are formed, and the main piezoelectric vibrator located inside the two piezoelectric vibrators is moved outward. It is formed of a piezoelectric vibrator that has a larger piezoelectric constant and Poisson's ratio than the sub piezoelectric vibrator located and has a polarization direction perpendicular to the non-adhesive surface of the vibrator. When the main piezoelectric vibrator is vibrated in a direction perpendicular to the non-adhesive surface of the transducer by applying a phase electric signal, the main piezoelectric vibrator contracts in the non-adhesive surface direction of the vibrator according to the Poisson's ratio, and The vibrator expands so as to compensate for the contraction of the main piezoelectric vibrator, and the main piezoelectric vibrator apparently does not contract in the direction of the non-adhesive surface of the vibrator.

Accordingly, vibration in the direction of the non-adhesive surface of the piezoelectric vibrator in the vibrator non-bonding surface can be suppressed, and good acoustic radiation efficiency can be obtained.

In addition, since cork or the like conventionally required for obtaining good sound radiation efficiency is not required, it can be used even at a position where the water depth is considerably deep, and the degree of freedom in use can be increased.

Further, the ability to suppress vibration in the direction of the non-adhesive surface of the vibrator allows the sound radiating surface to be a uniform vibrating surface due to the baffle effect, thereby obtaining good directivity in sound radiation.

[Brief description of the drawings]

FIGS. 1A and 1B are external perspective views showing an example of use of a vibration source for a transmitter according to a first embodiment of the present invention, and FIGS.
It is a -b local sectional view.

FIG. 2 is a sectional view showing a vibration source for a transmitter according to the first embodiment of the present invention.

FIGS. 3A and 3B are cross-sectional views illustrating a state before vibration and a state during vibration of a piezoelectric vibrator in a vibration source for a transmitter according to a first embodiment of the present invention.

FIGS. 4A and 4B are external perspective views showing an example of use of a vibration source for a transmitter according to a second embodiment of the present invention, and FIGS.
It is -b sectional drawing.

FIGS. 5A and 5B are external perspective views showing an example of use of a vibration source for a transmitter according to a third embodiment of the present invention, and FIGS.
It is -b sectional drawing.

FIG. 6 is a cross-sectional view for explaining the operation of the piezoelectric vibrator when applying a voltage.

7 (a) and 7 (b) are an external perspective view and a bb cross-sectional view showing a conventional vibration source (1) for a transmitter.

8 (a) and 8 (b) are an external perspective view and a bb sectional view showing a conventional vibration source (2) for a transmitter.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electroacoustic transducer 2 Vibration source for transmitter 3 Baffle table 4 Case 5, 6 Piezoelectric vibrator 7, 8 Lead wire

Claims (6)

[Claims] 1. Two main and sub piezoelectric vibrators which are adhered to each other inside and outside and vibrate by electric signals which can be applied independently of each other, and each of these piezoelectric vibrators has a polarization direction perpendicular to each other. The main piezoelectric vibrator located inside the two piezoelectric vibrators has a larger piezoelectric constant and Poisson's ratio than the sub piezoelectric vibrator located outside, and is perpendicular to the non-adhesive surface of the vibrator. A vibration source for a transmitter, comprising a piezoelectric vibrator having a polarization direction in a direction. 2. The piezoelectric device according to claim 1, wherein the main piezoelectric vibrator is formed by a cylindrical member, and the sub-piezoelectric vibrator is formed by a cylindrical member that opens in both axial directions.
The vibration source for the transmitter according to the above. 3. The vibration source for a transmitter according to claim 2, wherein the sub-piezoelectric vibrator comprises a number of vibrator elements arranged in a circumferential direction. 4. The main piezoelectric vibrator is formed by a single rectangular member, and the sub piezoelectric vibrator is formed by two rectangular members sandwiching the main piezoelectric vibrator. 2. The vibration source for a transmitter according to 1. 5. The vibration source for a transmitter according to claim 4, wherein said main piezoelectric vibrator comprises a number of vibration elements arranged in parallel in a direction perpendicular to a polarization direction. 6. The vibration source for a transmitter according to claim 1, wherein each of the piezoelectric vibrators is a piezoelectric vibrator of an acoustic transducer.