JP5309941B2 - Acoustic transducer - Google Patents

Description

  The present invention relates to an acoustic transducer, and more particularly, to an acoustic transducer that radiates acoustically into water using, for example, a cylindrical piezoelectric vibrator, a flexural type transmitter composed of an elliptical cylindrical shell, or the like.

  In an acoustic transducer that radiates acoustically into the water using a cylindrical piezoelectric vibrator, a flexural type transmitter composed of an elliptical cylindrical shell, etc., end plates are placed at both ends through cushioning materials. The openings are sealed. By this buffer material, the obstruction by the end plate with respect to the vibration of the piezoelectric vibrator or the transmitter is reduced.

  For example, as shown in FIG. 9, this type of acoustic transducer includes a cylindrical active vibrator 1, cushioning materials 2, 2, end plates 3, 3, and a sheath (or mold) 4. The cylindrical active vibrator 1 is configured by forming electrodes 1b on the outer and inner surfaces of a cylindrical piezoelectric ceramic vibrator 1a. The openings at both ends of the cylindrical active vibrator 1 are sealed by providing end plates 3 and 3 with cushioning materials 2 and 2, and the whole is covered with a sheath (or mold) 4. A cavity V is formed inside the cylindrical active vibrator 1. The end plates 3 and 3 prevent an external liquid from flowing into the cavity V. A cable (not shown) for applying an AC voltage to the cylindrical active vibrator 1 from the outside is connected to the electrode 1b.

FIG. 10 is a schematic diagram for explaining the operation of the acoustic transducer of FIG.
In this acoustic transducer, when an AC voltage is applied to the cylindrical active vibrator 1, a respiration vibration whose diameter is uniformly increased or decreased at the natural frequency is generated by the piezoelectric phenomenon of the cylindrical piezoelectric ceramic vibrator 1 a, and the displacement dp Sound pressure sa occurs. In this case, since the buffer materials 2 and 2 are deformed corresponding to the displacement dp, the inhibition by the end plates 3 and 3 with respect to the vibration of the cylindrical active vibrator 1 is reduced.

FIG. 11 is a cross-sectional perspective view showing another configuration example of the acoustic transducer. Elements common to the elements in FIG. 9 are denoted by common reference numerals.
In this acoustic transducer, instead of the cylindrical active vibrator 1 in FIG. 9, a cylindrical active vibrator 1A having a different configuration is provided. The cylindrical active vibrator 1A is formed by an assembly in which a plurality of rectangular piezoelectric ceramic vibrators 1c are arranged and joined on the circumference, and each vibrator 1c is polarized in the circumferential direction, that is, in the thickness direction. Further, an electrode 1d is provided on the joint surface of each vibrator 1c. This acoustic transducer also performs substantially the same operation as in FIG.

In addition to the acoustic transducer described above, as a related technique of this type, there is a low-frequency underwater transmitter described in Patent Document 1, for example.
This transmitter is composed of a bent disk type resonator and a cylindrical Helmholtz type resonator, and the same bent disk type consisting of an active disk body and a metal disk at both ends of the Helmholtz type resonator. Each resonator is joined one by one. The Helmholtz resonator is filled with silicon oil inside the cylinder to compensate for external pressure, and can achieve a working depth of 1000 m or more. In this transmitter, by making the resonance frequency of the Helmholtz resonator coincide with the resonance frequency of the bent disk resonator, the amplitude of the acoustic radiation surface is increased and high power radiation is possible. Further, the resonance frequency of the Helmholtz resonator can be varied by adjusting a slit formed in the cylindrical side surface to an appropriate size.
Japanese Patent Laid-Open No. 06-311577 (abstract, FIG. 1)

However, the acoustic transducer including the transmitter described in the above literature has the following problems.
That is, in the acoustic transducer of FIG. 9 or FIG. 11, the buffer materials 2 and 2 reduce the obstruction by the end plates 3 and 3 with respect to the vibration of the cylindrical active vibrator 1, but ensure the water pressure resistance. For this reason, since the buffer materials 2 and 2 are formed thin, there is a problem that the effect of the buffer materials 2 and 2 is reduced and efficiency and directivity are lowered. Further, when the water pressure is applied, the molding material or the like may bite into the buffer materials 2 and 2, and the uniform vibration of the side surface of the cylindrical active vibrating body 1 is obstructed, and the efficiency and directivity increase as the water pressure increases. There is also a problem in that a reduced hydraulic pressure characteristic occurs.

  Further, in the transmitter described in Patent Document 1, the acoustic radiation surface is a direction along the central axis of the active disk body, that is, a disk-shaped circular surface, and is acoustically radiated in the cylindrical axis direction. There is almost no acoustic radiation in the radial direction from the side surface of the Helmholtz resonator and the metal disk forming the cylindrical side surface. Further, since the active disk is joined to the metal disk, the bending vibration generated in the active disk due to the upper and lower asymmetry is utilized. For this reason, in these disc bodies, flexural vibration is always excited due to structural asymmetry, while radial uniform vibration is not excited, and the above-mentioned problems are not improved.

  The present invention has been made in view of the above-described circumstances, has a structure with the same external dimensions as the conventional one, enables more efficient acoustic radiation, has a high water pressure resistance, and electroacoustic conversion efficiency by water pressure. An object of the present invention is to provide an acoustic transducer in which there is little decrease in the directional characteristics of the radiated sound wave and the directivity variation of the emitted sound wave.

In order to solve the above-described problems, a first configuration of the present invention relates to an acoustic transducer, which is formed in a cylindrical shape and whose diameter is uniformly increased or decreased at a specific frequency by a piezoelectric phenomenon generated by an applied AC voltage. A cylindrical active vibrator that generates respiratory vibrations and a pair of end plates for sealing openings at both ends of the cylindrical active vibrator, and each of the end plates is formed into a cylindrical shape by a piezoelectric phenomenon. The active vibration body is composed of a disk-shaped active vibration body that generates radial vibrations having the same phase, the same amplitude, and the same frequency as the natural frequency.

  A second configuration of the present invention relates to an acoustic transducer, and includes a drive module having an elliptical cylindrical shell, in which a predetermined number of vibrators are stacked in the major axis direction of the shell, and the drive module The elliptical shell that generates vibrations of a specific frequency that alternately expands and contracts in the major axis direction and the minor axis direction is excited by the alternating voltage applied to the major axis, and the openings at both ends of the elliptical shell are sealed. Each end plate is formed by arranging a plurality of rectangular plates that are long in the minor axis direction (or major axis direction) in the major axis direction (or minor axis direction), It is characterized in that it generates a stretching vibration in the length direction having the same phase, the same amplitude and the same frequency as the bending vibration of the elliptical shell.

According to the configuration of the present invention, each end plate made of the disk-shaped active vibrating body generates radial vibrations having the same phase, the same amplitude, and the same frequency as the respiratory vibration of the cylindrical active vibrating body. Since the end plates do not inhibit the respiratory vibration of the vibrating body, it is possible to realize an acoustic transducer with good electroacoustic conversion efficiency and low water pressure characteristics. In addition, since the vibration distribution on the outer surface of the cylindrical active vibrator becomes more uniform in the axial direction, an acoustic transducer having sharper acoustic radiation directivity can be realized. Also, there is no cushioning material between each end plate and the cylindrical active vibrating body, or it is only necessary to have a very thin cushioning material, so that higher water pressure resistance can be obtained and it can be used at deeper depths. An acoustic transducer with a small water pressure characteristic can be realized. For the same reason, a sheath or a synthetic resin mold provided so that surrounding liquid does not enter the inside may be very thin, and a lighter acoustic transducer can be realized.

  Further, according to the configuration of the present invention, each end plate formed by arranging a plurality of rectangular plates long in the minor axis direction (or major axis direction) of the elliptical shell in the major axis direction (or minor axis direction) Since the stretching vibration in the length direction of the same phase, the same amplitude and the same frequency as the bending vibration is generated, a waterproof structure can be realized without hindering the vibration of the same elliptical shell. Thereby, it is possible to realize an acoustic transducer with extremely low water pressure characteristics. In addition, by arranging a plurality of rectangular plate-shaped piezoelectric ceramic vibrators in the major axis direction (or minor axis direction) of the elliptical shell, obstruction to vibrations in the major axis direction (or minor axis direction) can be avoided, and acoustic radiation efficiency can be avoided. Can be prevented.

A cylindrical active vibrator that is formed in a cylindrical shape and generates a respiratory vibration whose diameter is uniformly increased or decreased by a piezoelectric phenomenon generated by an applied AC voltage, and openings at both ends of the cylindrical active vibrator Each of the end plates has the same phase, the same amplitude and the same frequency as the natural frequency due to the piezoelectric phenomenon. Provided is an acoustic transducer composed of a disk-shaped active vibrating body that generates radial vibration.

  In a preferred embodiment of the present invention, the disk-shaped active vibrator is formed on both surfaces of a disk-shaped piezoelectric vibrator in which the radial vibration is generated by a piezoelectric phenomenon, and the disk-shaped piezoelectric vibrator, An electrode for generating the piezoelectric phenomenon in the disk-shaped piezoelectric vibrator by a given driving voltage, and the diameter generated by the disk-shaped piezoelectric vibrator, the disk-shaped piezoelectric vibrator being pasted on both surfaces It consists of a disk-shaped resonance plate that resonates with directional vibration.

  Also, in a preferred embodiment of the present invention, the disk-shaped active vibrator includes the disk-shaped piezoelectric vibrator, the material, shape and dimensions of the electrode and the disk-shaped resonance plate, and the driving voltage is the respiratory vibration. Are set so as to correspond to the same frequency as the above-mentioned phase, amplitude and natural frequency.

  In a preferred embodiment of the present invention, the disk-shaped active vibrator is formed on both surfaces of a disk-shaped piezoelectric vibrator in which the radial vibration is generated by a piezoelectric phenomenon, and the disk-shaped piezoelectric vibrator, An electrode for generating the piezoelectric phenomenon in the disc-shaped piezoelectric vibrator by a given drive voltage.

  Further, in a preferred embodiment of the present invention, the disk-shaped active vibrator includes the disk-shaped piezoelectric vibrator and electrode material, shape and dimensions, and the driving voltage, the phase, amplitude and It is set to correspond to the same frequency as the specific frequency.

  In a preferred embodiment of the present invention, the disk-shaped active vibrator is provided with a reinforcing member for reinforcing the mechanical strength of the disk-shaped active vibrator.

  In a preferred embodiment of the present invention, the cylindrical active vibrator is formed of a single cylindrical piezoelectric vibrator or an aggregate formed by arranging and joining a plurality of rectangular piezoelectric vibrators on the circumference. Yes.

  In a preferred embodiment of the present invention, a drive module having an elliptical cylindrical shell and having a predetermined number of piezoelectric vibrators stacked in the major axis direction inside the shell is incorporated and applied to the drive module. For sealing the elliptical shell that generates the flexural vibration of the inherent frequency that is alternately expanded and contracted in the major axis direction and the minor axis direction by the vibration of the major axis direction excited by the alternating voltage, and the opening at both ends of the elliptic shell Each of the end plates is formed by arranging a plurality of rectangular plates that are long in the minor axis direction (or major axis direction) in the major axis direction (or minor axis direction). It is configured to generate a stretching vibration in the length direction having the same phase, the same amplitude as the flexural vibration, and the same frequency as the specific frequency.

  According to a preferred embodiment of the present invention, each end plate is composed of a plurality of rectangular plate-like resonant plates that resonate with the flexural vibration of the elliptical shell and generate the stretching vibration.

  According to a preferred embodiment of the present invention, the rectangular plate-like resonator plate corresponds to the same frequency, material, shape, and dimensions of the rectangular plate-like resonator plate as the phase, amplitude, and intrinsic frequency of the stretching vibration. It is set to be.

  According to a preferred embodiment of the present invention, each of the end plates has a plurality of rectangular shapes in which expansion vibrations having the same phase, the same amplitude, and the same frequency as the inherent frequency are generated by the piezoelectric phenomenon. It is composed of a plate-like active vibrator.

  In a preferred embodiment of the present invention, the rectangular plate-like active vibrator is formed on both sides of a rectangular plate-like piezoelectric vibrator in which the stretching vibration is generated by a piezoelectric phenomenon and the rectangular plate-like piezoelectric vibrator. Electrodes for generating the piezoelectric phenomenon in the rectangular plate-shaped piezoelectric vibrator by the applied drive voltage, and the stretching vibration generated by the rectangular plate-shaped piezoelectric vibrator, the rectangular plate-shaped piezoelectric vibrator being attached to both surfaces And a rectangular plate-like resonance plate that resonates with the plate.

  Also, in a preferred embodiment of the present invention, the rectangular plate-like active vibrator is configured such that the material, shape, and dimensions of the rectangular plate-like piezoelectric vibrator, the electrode and the rectangular plate-like resonance plate, and the driving voltage are the stretching vibration. Are set so as to correspond to the same frequency as the above-mentioned phase, amplitude and natural frequency.

  In a preferred embodiment of the present invention, the rectangular plate-like active vibrator is formed on both sides of a rectangular plate-like piezoelectric vibrator in which the stretching vibration is generated by a piezoelectric phenomenon and the rectangular plate-like piezoelectric vibrator. An electrode for generating the piezoelectric phenomenon in the rectangular plate-shaped piezoelectric vibrator by the driven voltage.

  Also, in a preferred embodiment of the present invention, the rectangular plate-shaped active vibrator includes a material, shape and size of the rectangular plate-shaped piezoelectric vibrator and electrode, and the driving voltage, the phase, amplitude and It is set to correspond to the same frequency as the specific frequency.

  In a preferred embodiment of the present invention, the rectangular plate-like active vibrator is provided with a reinforcing member for reinforcing the mechanical strength of the rectangular plate-like active vibrator.

Embodiment 1

FIG. 1 is a cross-sectional perspective view showing a configuration of a main part of an acoustic transducer according to the first embodiment of the present invention.
As shown in the figure, the acoustic transducer of this embodiment includes a cylindrical active vibrating body 11, disk-shaped resonance plates 12 and 12, and a sheath (or mold) 13. The cylindrical active vibrator 11 is configured by forming electrodes 11b on the outer surface and the inner surface of a cylindrical piezoelectric ceramic vibrator 11a. The electrode 11b is made of, for example, a silver electrode, and is connected to a cable (not shown) for applying an AC voltage to the cylindrical active vibrator 11 from the outside. The cylindrical active vibrator 11 generates a respiratory vibration whose diameter is uniformly increased or decreased at a frequency unique to the cylindrical piezoelectric ceramic vibrator 11a by a piezoelectric phenomenon generated by an applied AC voltage.

  The openings at both ends of the cylindrical active vibrator 11 are sealed by providing disc-shaped resonance plates 12 and 12, and the whole is covered with a sheath (or mold) 13. The material of the sheath 13 is rubber, for example, and the material of the mold is synthetic resin. The sheath (or mold) 13 prevents an electrical short circuit due to a surrounding liquid such as water or mechanical damage to the outer surfaces of the cylindrical active vibrator 11 and the disk-shaped resonator plates 12 and 12. To do. A cavity V is formed inside the cylindrical active vibrator 11. In addition to preventing the flow of external liquid into the cavity V, the disc-shaped resonance plate 12 resonates with the breathing vibration of the cylindrical active vibrator 11 and has the same phase as that of the breathing vibration. , And generate radial vibrations having the same amplitude and the same frequency as the specific frequency. The disc-shaped resonance plate 12 is set so that the material, shape and dimensions thereof correspond to the same frequency as the phase, amplitude and specific frequency of the respiratory vibration.

FIG. 2 is a diagram showing the directivity characteristics of the acoustic transducers of FIGS. 1 and 9.
The operation of the acoustic transducer of this embodiment will be described with reference to this figure.
In this acoustic transducer, when an AC voltage is applied to the cylindrical active vibrator 11, a respiratory vibration whose diameter is uniformly increased or decreased at a specific frequency is generated by the piezoelectric phenomenon of the cylindrical piezoelectric ceramic vibrator 11 a, and the cylinder As a result, displacement of the side surface of the active vibrating body 11 occurs and sound pressure is generated, and acoustic radiation is performed in the surrounding liquid. In this case, the disk-shaped resonance plates 12 and 12 resonate with the breathing vibration of the cylindrical active vibrator 11, and generate radial vibrations having the same phase, the same amplitude, and the same frequency as the natural vibration. In addition, the obstruction caused by the disk-like resonant plates 12 and 12 with respect to the respiratory vibration of the cylindrical active vibrator 11 is reduced.

  In FIG. 2, the directional characteristics with reference to the plane perpendicular to the axis of the cylinder constituting the acoustic transducer (0 degree) are shown in polar coordinates. In the acoustic transducer of FIG. 1, as shown in FIG. 2, a sharp directional characteristic db is obtained as compared with the directional characteristic da of the acoustic transducer of FIG. Thereby, electroacoustic conversion efficiency is favorable and water pressure characteristics are reduced.

  As described above, in the first embodiment, the disk-shaped resonance plates 12 and 12 generate radial vibrations having the same phase, the same amplitude, and the same frequency as the radial vibrations of the cylindrical active vibrator 11. Thus, an acoustic transducer with good electroacoustic conversion efficiency and low water pressure characteristics is realized. Further, since there is no buffer material or a very thin buffer material between the disk-shaped resonator plates 12 and 12 and the cylindrical active vibrator 11, a higher water pressure resistance can be obtained and deeper. An acoustic transducer with low water pressure characteristics that can be used at a depth is realized. For the same reason, the sheath (or mold) 13 may be very thin, and a lighter acoustic transducer is realized.

Embodiment 2

FIG. 3 is a cross-sectional perspective view showing the configuration of the main part of the acoustic transducer according to the second embodiment of the present invention. Elements common to the elements in FIG. 1 showing the first embodiment are denoted by common reference numerals. Is attached.
In the acoustic transducer of this embodiment, as shown in FIG. 3, instead of the disk-shaped resonance plates 12 and 12 and the sheath (or mold) 13 in FIG. 1, the disk-shaped resonance plates 12A and 12A and the sheath (or (Mold) 13A, disk-shaped piezoelectric ceramic vibrators 14 and 14, and electrodes 15, ..., 15 are provided. The disc-shaped piezoelectric ceramic vibrator 14 generates radial vibration due to a piezoelectric phenomenon. The electrodes 15 are formed on both surfaces of the disk-shaped piezoelectric ceramic vibrator 14 (for example, pasting, adhering, etc.), and generate a piezoelectric phenomenon in the disk-shaped piezoelectric ceramic vibrator 14 by a given driving voltage.

  The disk-shaped resonance plate 12A has disk-shaped piezoelectric ceramic vibrators 14 and 14 attached to both surfaces thereof, and resonates with the radial vibration generated by these disk-shaped piezoelectric ceramic vibrators 14 and 14 to cause radial vibration. Occur. These disk-shaped resonance plate 12A, disk-shaped piezoelectric ceramic vibrator 14 and electrode 15 constitute a disk-shaped active vibration body 16. The disk-like active vibrating body 16 generates radial vibrations having the same phase and the same amplitude as the breathing vibration of the cylindrical active vibrating body 11 and the same frequency as the specific frequency by the piezoelectric phenomenon. In this case, in the disk-shaped active vibrating body 16, the material, shape and dimensions of the disk-shaped piezoelectric ceramic vibrator 14, the electrode 15 and the disk-shaped resonance plate 12A, and the driving voltage are determined by the phase and amplitude of the respiratory vibration. And the same frequency as the specific frequency.

  In addition, the two piezoelectric ceramic vibrators 14 and 14 are not normally used bimorph structures, and the polarization direction and the voltage application direction are set so that the radial vibration is excited in the same direction and the diameter expands or contracts at the same time. Thus, bending vibration is avoided. In the piezoelectric ceramic vibrators 14 and 14, the piezoelectric constant, size, and shape are also selected so that bending resonance does not occur in the disc-shaped resonance plate 12 </ b> A. If the disk-shaped piezoelectric ceramic vibrator 14 is attached to only one surface of the disk-shaped resonance plate 12A, bending vibration is generated in the disk-shaped resonance plate 12A. In order to avoid this, it is applied to both surfaces. There is a need. As a result, the piezoelectric ceramic vibrators 14 and 14 do not generate a large tensile stress due to the water pressure, so that the water pressure resistance is ensured. The sheath (or mold) 13 </ b> A <b> 13 </ b> A has a shape different from that of the sheath 13 corresponding to the shape of the disk-shaped active vibrating body 16, and the outer surface of the cylindrical active vibrating body 11 and the disk-shaped active vibrating body 16. Prevent electrical short circuit or mechanical damage by surrounding liquid such as water. The other configuration is the same as that shown in FIG.

FIG. 4 is a diagram for explaining a vibration distribution by the acoustic transducer of FIG.
The operation of the acoustic transducer of this embodiment will be described with reference to this figure.
In this acoustic transducer, when an AC voltage is applied to the cylindrical active vibrator 11, the diameter is uniform at a specific frequency due to the piezoelectric phenomenon of the cylindrical piezoelectric ceramic vibrator 11a, as in the first embodiment. As shown in FIG. 4, a displacement dp of the side surface of the cylindrical active vibrating body 11 is generated and a sound pressure sa is generated, and acoustic radiation is performed in the surrounding liquid. In this case, in the disk-shaped active vibrator 16, radial vibration having the same phase, the same amplitude, and the same frequency as the natural frequency is generated due to the piezoelectric phenomenon, and the cylindrical active vibration is generated. Inhibition of respiratory vibrations of the body 11 is reduced.

  Since the displacement dp of the cylindrical active vibrating body 11 and the displacement fe of the disk-like active vibrating body 16 are equal and no stress is generated at the joint portion between the cylindrical active vibrating body 11 and the disk-like active vibrating body 16, the sheath Intrusion of liquids such as water can be reliably prevented even if the mold made of or synthetic resin is thin or not. Further, with this structure, it is not necessary to put a cushioning material on the joint surface between the both end faces of the cylindrical active vibrator 11 and the disk-like active vibrators 16 and 16, and the water pressure resistance can be increased. Further, since the disc-like active vibrator 16 only needs to obtain a vibration displacement in the breathing direction at the breathing vibration frequency of the cylindrical active vibrator 11, the thickness thereof can be freely set according to the required water pressure resistance. be able to. Also in this acoustic transducer, a sharp directivity characteristic db as shown in FIG. 2 can be obtained as in the first embodiment.

Embodiment 3

FIG. 5 is a cross-sectional perspective view showing the configuration of the main part of an acoustic transducer according to the third embodiment of the present invention. Elements common to the elements in FIG. 3 showing the second embodiment are denoted by common reference numerals. Is attached.
In the acoustic transducer of this embodiment, as shown in FIG. 5, instead of the disk-like active vibrators 16 and 16 and the sheath (or mold) 13A in FIG. 16A and a sheath (or mold) 13B are provided. The disc-shaped active vibrator 16A is composed of a disc-shaped piezoelectric ceramic vibrator 14A and electrodes 15A, 15A having a different shape from the disc-shaped piezoelectric ceramic vibrator 14 and electrodes 15, 15 in FIG. The disc-shaped piezoelectric ceramic vibrator 14A generates radial vibration due to a piezoelectric phenomenon.

  The electrodes 15A, 15A are formed on both surfaces of the disk-shaped piezoelectric ceramic vibrator 14A (for example, pasting, attaching, etc.), and generate a piezoelectric phenomenon in the disk-shaped piezoelectric ceramic vibrator 14A by a given driving voltage. In this case, in the disk-shaped active vibrating body 16A, the material, shape, and dimensions of the disk-shaped piezoelectric ceramic vibrator 14A and the electrode 15A, and the drive voltage are the same as the phase, amplitude, and specific frequency of the respiratory vibration. It is set to correspond to the frequency. The sheath (or mold) 13B has a shape different from that of the sheath 13A corresponding to the shape of the disk-shaped active vibration body 16A, and the outer surface of the cylindrical active vibration body 11 and the disk-shaped active vibration body 16A. Prevent electrical short circuit or mechanical damage by surrounding liquid such as water. The other configuration is the same as in FIG. This acoustic transducer also performs substantially the same operation as in the second embodiment and has the same advantages.

Embodiment 4

FIG. 6 is a cross-sectional perspective view showing a configuration of a main part of an acoustic transducer according to a fourth embodiment of the present invention. Elements common to the elements in FIG. 5 illustrating the third embodiment are denoted by common reference numerals. Is attached.
In the acoustic transducer of this embodiment, as shown in FIG. 6, instead of the disk-like active vibrators 16A and 16A and the sheath (or mold) 13B in FIG. 16B and a sheath (or mold) 13C are provided. The disk-shaped active vibrators 16B and 16B are formed of the disk-shaped piezoelectric ceramic vibrator 14B and the electrodes 15B and 15B, and the reinforcing plate 17 having shapes different from those of the disk-shaped piezoelectric ceramic vibrator 14A and the electrodes 15A and 15A in FIG. , 17. The disc-shaped piezoelectric ceramic vibrator 14B generates radial vibrations due to a piezoelectric phenomenon.

  The electrodes 15B and 15B are formed on both surfaces of the disk-shaped piezoelectric ceramic vibrator 14B (for example, pasting, attaching, etc.), and generate a piezoelectric phenomenon in the disk-shaped piezoelectric ceramic vibrator 14B with a given drive voltage. The reinforcing plates 17 and 17 are made of a highly rigid material such as metal or synthetic resin, and are formed (attached, adhered, etc.) on both surfaces of the disk-shaped piezoelectric ceramic vibrator 14B on which the electrodes 15B and 15B are formed. Yes. The reinforcing plates 17 and 17 have a function of reinforcing the mechanical strength of the disk-shaped active vibrating body 16B. Since the disk-shaped piezoelectric ceramic vibrator 14B is weak against tensile stress, it may be damaged when stress such as water pressure increases. However, the reinforcing plates 17 and 17 have a function of reducing the tensile stress, and are disk-shaped. The active vibrating body 16B is configured to withstand a large water pressure. In addition, even if the reinforcing plate 17 is formed on only one surface of the disk-shaped piezoelectric ceramic vibrator 14B, it has a function according to the case where the reinforcing plate 17 is formed on both surfaces.

  The sheath (or mold) 13C has a shape different from that of the sheath 13B corresponding to the shape of the disk-shaped active vibrating body 16B, and the outer surface of the cylindrical active vibrating body 11 and the disk-shaped active vibrating body 16B. Prevent electrical short circuit or mechanical damage by surrounding liquid such as water. The other configuration is the same as that of FIG. This acoustic transducer also performs substantially the same operation as in the third embodiment, has the same advantages, and provides a large water pressure resistance.

Embodiment 5

FIG. 7 is a cross-sectional perspective view showing the configuration of the main part of an acoustic transducer according to the fifth embodiment of the present invention.
As shown in FIG. 7, the acoustic transducer of this form includes an elliptical shell 21, a drive module 22, rectangular plate-like active vibrators 23 and 23, and a sheath (or mold) 24. The elliptical shell 21 is configured as a flexural type transmitter, has an elliptical cylindrical shell, and incorporates a drive module 22 configured by laminating a predetermined number of piezoelectric vibrators in the inner major axis direction, A vibration in the major axis direction is excited by the AC voltage applied to the drive module 22 to generate a flexural vibration having a specific frequency that alternately expands and contracts in the major axis direction and the minor axis direction.

  The rectangular plate-like active vibrators 23 and 23 have a function of sealing the openings at both ends of the elliptical shell 21. In particular, in this embodiment, the rectangular plate-like piezoelectric ceramic vibrator 23a that is long in the short-diameter direction is provided in the long-diameter direction. The electrodes 23b and 23b are formed on both surfaces of each rectangular plate-shaped piezoelectric ceramic vibrator 23a. The electrode 23b is made of, for example, a silver electrode. A thin buffer material (not shown) is provided between the rectangular plate-shaped piezoelectric ceramic vibrators 23a. The electrode 23b generates a piezoelectric phenomenon in the rectangular plate-shaped piezoelectric ceramic vibrator 23a by a given driving voltage. Thereby, the rectangular plate-like active vibrating body 23 generates a stretching vibration in the length direction having the same phase, the same amplitude, and the same frequency as the bending frequency of the elliptical shell 21. In this rectangular plate-shaped active vibrator 23, the material, shape and dimensions of the rectangular plate-shaped piezoelectric ceramic vibrator 23a and the electrode 23b, and the driving voltage correspond to the same frequency as the phase, amplitude and natural frequency of the vibration. It is set to be. A sheath (or mold) 24 covers the entire acoustic transducer and prevents electrical shorting or mechanical damage from surrounding liquids such as water. A cavity V is formed inside the elliptical shell 21.

  In this acoustic transducer, the vibration in the major axis direction of the elliptical shell 21 is excited by the alternating voltage applied to the drive module 22, thereby generating a flexural vibration with a specific frequency that alternately expands and contracts in the major axis direction and the minor axis direction. A sound pressure sa is generated. In this state, the rectangular plate-like active vibrator 23 is driven so that the phase, amplitude, and frequency of the stretching vibration in the length direction (that is, the stretching direction fd) are equal to the phase, amplitude, and frequency of the bending vibration of the elliptic shell 21. By doing so, a waterproof structure is realized without disturbing the vibration of the elliptical shell 21. As a result, an acoustic transducer having very little water pressure characteristics is realized. In addition, a plurality of rectangular plate-shaped piezoelectric ceramic vibrators 23a are arranged in the major axis direction of the elliptical shell 21, and a buffer material is provided between each rectangular plate-shaped piezoelectric ceramic vibrator 23a, thereby preventing vibration in the major axis direction. Inhibition is avoided, and a decrease in acoustic radiation efficiency can be prevented.

  Further, the arrangement direction of the rectangular plate-shaped piezoelectric ceramic vibrators 23a is preferably the long diameter direction with little vibration displacement, but the same advantage can be obtained even if the arrangement is not the long diameter direction but the short diameter direction. In this case, for the vibration in the minor axis direction of the elliptical shell 21, the rectangular plate-like active vibrating body is vibrated in the longitudinal direction, and the phase, amplitude and frequency thereof are the phase, amplitude and frequency of the flexural vibration of the elliptical shell 21. To prevent the elliptical shell 21 from vibrating in the minor axis direction is reduced.

The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to the embodiment, and even if there is a design change without departing from the gist of the present invention, Included in the invention.
For example, in the first to fourth embodiments, the cylindrical active vibrating body 11 is used. However, instead of the cylindrical active vibrating body 11, as shown in FIG. A vibrating body 11A may be used (corresponding to claim 11). The cylindrical active vibrator 11A is formed of an assembly in which a plurality of rectangular piezoelectric ceramic vibrators 11c are arranged and joined on the circumference, and the individual vibrators 11c are polarized in the circumferential direction, that is, in the thickness direction. Further, an electrode 11d is provided on the joint surface of each vibrator 11c.

  The openings at both ends of the cylindrical active vibrator 11A are sealed by providing the disk-shaped resonance plates 12 and 12 via the buffer materials 18 and 18, and the whole is covered with the sheath (or mold) 13. . The buffer members 18 and 18 have an insulating function for avoiding a short circuit between the respective electrodes 11d, but may be omitted when the disk-shaped resonance plates 12 and 12 are made of an insulating material. This acoustic transducer also performs substantially the same operation as in the first to fourth embodiments. Further, instead of the disk-shaped resonance plates 12 and 12 in FIG. 8, the disk-shaped active vibration bodies 16 and 16 in FIG. 3, the disk-shaped active vibration bodies 16A and 16A in FIG. The disc-like active vibrators 16B and 16B may be provided.

  In the fifth embodiment, the rectangular plate-like active vibrating bodies 23 and 23 are provided as end plates. However, the rectangular plate-like resonance plate that resonates with the bending vibration of the elliptical shell 21 and generates stretching vibrations. (It corresponds to claim 14). In this case, the material, shape, and dimensions of the rectangular plate-like resonant plate are set so as to correspond to the same frequency as the phase, amplitude, and natural frequency of the stretching vibration (corresponding to claim 15).

  In addition, the rectangular plate-like active vibrator as an end plate is formed on both sides of a rectangular plate-like piezoelectric vibrator that generates stretching vibration due to a piezoelectric phenomenon, and is applied by a given drive voltage. An electrode for generating a piezoelectric phenomenon in a rectangular plate-shaped piezoelectric vibrator, and a rectangular plate-shaped resonant plate that is attached to both surfaces of the rectangular plate-shaped piezoelectric vibrator and resonates with the stretching vibration generated by the rectangular plate-shaped piezoelectric vibrator (Corresponding to claim 17). In this case, the material, shape and dimensions of the rectangular plate-shaped piezoelectric vibrator, the electrode and the rectangular plate-shaped resonance plate, and the driving voltage correspond to the same frequency as the phase, amplitude and intrinsic frequency of the stretching vibration. It is set (corresponding to claim 18). Further, these rectangular plate-like active vibrators may be provided with a reinforcing member on both sides or one side for reinforcing the mechanical strength of the rectangular plate-like active vibrator (corresponding to claim 21).

  In addition, the piezoelectric ceramic vibrator in each of the above embodiments is realized by using a piezoelectric ceramic laminate in which a plurality of thin piezoelectric vibratory materials are laminated when the required resonance frequency or displacement cannot be realized when used alone. You may do it. In each of the above embodiments, a piezoelectric ceramic vibrator is used. However, if an AC voltage is applied and the material expands and contracts in the radial direction, for example, an electrostrictive material or the like can be used. Almost the same operation and effect can be obtained.

  The present invention can be applied to all acoustic transducers that radiate sound in water using a cylindrical piezoelectric vibrator, a flex-tensional type transmitter, or the like.

It is a section perspective view showing composition of an important section of an acoustic transducer which is a 1st embodiment of this invention. It is a figure which shows the directional characteristic of the acoustic transducer of FIG.1 and FIG.9. It is a cross-sectional perspective view which shows the structure of the principal part of the acoustic transducer which is 2nd Embodiment of this invention. It is a figure explaining the vibration distribution by the acoustic transducer of FIG. It is a cross-sectional perspective view which shows the structure of the principal part of the acoustic transducer which is the 3rd Embodiment of this invention. It is a cross-sectional perspective view which shows the structure of the principal part of the acoustic transducer which is 4th Embodiment of this invention. It is a cross-sectional perspective view which shows the structure of the principal part of the acoustic transducer which is 5th Embodiment of this invention. It is a cross-sectional perspective view which shows the modification of an acoustic transducer. It is a cross-sectional perspective view which shows the structural example of an acoustic transducer. It is a schematic diagram explaining the operation | movement of the acoustic transducer of FIG. It is a cross-sectional perspective view which shows the other structural example of an acoustic transducer.

Explanation of symbols

11 Cylindrical active vibrator (single unit)
11a Cylindrical piezoelectric ceramic vibrator (cylindrical piezoelectric vibrator)
11b Electrode 11A Cylindrical active vibrator (aggregate)
11c Rectangular piezoelectric ceramic resonator (rectangular piezoelectric resonator)
12, 12A Disc-shaped resonance plate 13, 13A, 13B, 13C Sheath (or mold)
14, 14A, 14B Disk-shaped piezoelectric ceramic vibrator (disk-shaped piezoelectric vibrator)
15, 15A, 15B Electrode 16, 16A, 16B Disc-shaped active vibrator 17 Reinforcement plate (reinforcement member)
18 Buffer material 21 Elliptical shell 22 Drive module 23 Rectangular plate active vibrator 23a Rectangular plate piezoelectric ceramic vibrator (rectangular plate piezoelectric vibrator)
23b Electrode 24 Sheath (or mold)

Claims (17)

A cylindrical active vibrating body that is formed in a cylindrical shape and generates a respiratory vibration whose diameter is uniformly increased or decreased by a piezoelectric phenomenon generated by an applied AC voltage;
A pair of end plates for sealing openings at both ends of the cylindrical active vibrator,
Each end plate is
It is composed of a disk-shaped active vibrating body that generates radial vibrations having the same phase, the same amplitude, and the same frequency as the natural frequency by the piezoelectric phenomenon as the respiratory vibration of the cylindrical active vibrating body. Acoustic transducer. The disk-shaped active vibrator is
A disk-shaped piezoelectric vibrator in which the radial vibration is generated by a piezoelectric phenomenon;
Electrodes formed on both sides of the disk-shaped piezoelectric vibrator, and for generating the piezoelectric phenomenon in the disk-shaped piezoelectric vibrator by a given driving voltage;
Said disk-like piezoelectric vibrator is stuck on both surfaces, according to claim 1, characterized in that it is constituted by said disk-like piezoelectric vibrator discoid resonant plate resonates in the radial vibrations generated by Acoustic transducer. The disk-shaped active vibrator is
The material, shape and dimensions of the disk-shaped piezoelectric vibrator, electrode and disk-shaped resonance plate, and the drive voltage are set to correspond to the same frequency as the phase, amplitude, and intrinsic frequency of the respiratory vibration. The acoustic transducer according to claim 2 , wherein the acoustic transducer is provided. The disk-shaped active vibrator is
A disk-shaped piezoelectric vibrator in which the radial vibration is generated by a piezoelectric phenomenon;
Is formed on both surfaces of the circular plate-shaped piezoelectric vibrator, claim, characterized in that it is composed of an electrode for generating the piezoelectric phenomenon circular plate type piezoelectric vibrator by a drive voltage given 1 The acoustic transducer as described. The disk-shaped active vibrator is
The material, shape and size of the disk-shaped piezoelectric vibrator and electrode, and the driving voltage are set so as to correspond to the same frequency as the phase, amplitude and intrinsic frequency of the respiratory vibration. The acoustic transducer according to claim 4 . The disk-shaped active vibrator is
6. The acoustic transducer according to claim 4, further comprising a reinforcing member for reinforcing the mechanical strength of the disk-shaped active vibrator. The cylindrical active vibrator is
Cylindrical piezoelectric vibrator alone, or a plurality of rectangular piezoelectric vibrator according to any one of claims 1 to 6, characterized in that it is formed by aggregates comprised are arranged and bonded on the circumference Acoustic transducer. A drive module having an elliptical cylindrical shell, in which a predetermined number of vibrators are laminated in the major axis direction inside the shell, is incorporated, and vibration in the major axis direction is excited by an AC voltage applied to the drive module. An elliptical shell that generates flexural vibrations of a specific frequency that alternately expands and contracts in the major axis direction and the minor axis direction,
A pair of end plates for sealing openings at both ends of the elliptical shell;
Each end plate is
A plurality of rectangular plates that are long in the minor axis direction (or major axis direction) are arranged in the major axis direction (or minor axis direction), and have the same phase, the same amplitude, and the same frequency as the flexural vibration of the elliptical shell. An acoustic transducer characterized by being configured to generate a stretching vibration. A drive module having an elliptical cylindrical shell and a predetermined number of piezoelectric vibrators stacked in the major axis direction inside the shell is incorporated, and vibration in the major axis direction is excited by an AC voltage applied to the drive module. An elliptical shell that generates flexural vibration of a specific frequency that is alternately expanded and contracted in the major axis direction and the minor axis direction;
A pair of end plates for sealing openings at both ends of the elliptical shell;
Each end plate is
A plurality of rectangular plates that are long in the minor axis direction (or major axis direction) are arranged in the major axis direction (or minor axis direction), and have the same phase, the same amplitude, and the same frequency as the flexural vibration of the elliptical shell. An acoustic transducer characterized by generating a stretching vibration in the longitudinal direction of the frequency of Each end plate is
The acoustic transducer according to claim 9 , wherein the acoustic transducer includes a plurality of rectangular plate-like resonance plates that resonate with the bending vibration of the elliptical shell and generate the stretching vibration. The rectangular plate-shaped resonance plate is
The acoustic material according to claim 10 , wherein a material, a shape, and a dimension of the rectangular plate-shaped resonance plate are set so as to correspond to the same frequency as the phase, amplitude, and natural frequency of the stretching vibration. Transducer. Each end plate is
The piezoelectric plate includes a plurality of rectangular plate-like active vibrators that generate expansion and contraction vibrations having the same phase, the same amplitude and the same frequency as the bending vibration of the elliptical shell due to a piezoelectric phenomenon. Item 10. The acoustic transducer according to Item 9 . The rectangular plate-like active vibrator is
A rectangular plate-like piezoelectric vibrator in which the stretching vibration is generated by a piezoelectric phenomenon;
Electrodes formed on both surfaces of the rectangular plate-shaped piezoelectric vibrator, and for generating the piezoelectric phenomenon in the rectangular plate-shaped piezoelectric vibrator by a given driving voltage;
The rectangular plate-like piezoelectric vibrator is stuck on both surfaces, according to claim 12, characterized in that it is composed of a rectangular plate-shaped resonant plate resonates in the stretching vibration generated in the rectangular plate piezoelectric vibrator Acoustic transducer. The rectangular plate-like active vibrator is
The material, shape and dimensions of the rectangular plate-shaped piezoelectric vibrator, electrode and rectangular plate-shaped resonance plate, and the driving voltage are set so as to correspond to the same frequency as the phase, amplitude and intrinsic frequency of the stretching vibration. 14. The acoustic transducer according to claim 13 , wherein the acoustic transducer is provided. The rectangular plate-like active vibrator is
A rectangular plate-like piezoelectric vibrator in which the stretching vibration is generated by a piezoelectric phenomenon;
Is formed on both surfaces of該矩form plate-like piezoelectric vibrator according to claim characterized in that it is composed of an electrode for generating the piezoelectric phenomenon該矩form plate-like piezoelectric vibrator by a drive voltage given 12 The acoustic transducer as described. The rectangular plate-like active vibrator is
The material, shape and size of the rectangular plate-shaped piezoelectric vibrator and electrode, and the driving voltage are set so as to correspond to the same frequency as the phase, amplitude and intrinsic frequency of the stretching vibration. The acoustic transducer according to claim 13 . The rectangular plate-like active vibrator is
The acoustic transducer according to claim 15 or 16, wherein a reinforcing member for reinforcing the mechanical strength of the rectangular plate-like active vibrator is provided.

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