JPH0441879B2 - - Google Patents
Info
- Publication number
- JPH0441879B2 JPH0441879B2 JP61019445A JP1944586A JPH0441879B2 JP H0441879 B2 JPH0441879 B2 JP H0441879B2 JP 61019445 A JP61019445 A JP 61019445A JP 1944586 A JP1944586 A JP 1944586A JP H0441879 B2 JPH0441879 B2 JP H0441879B2
- Authority
- JP
- Japan
- Prior art keywords
- acoustic radiation
- transducer
- piezoelectric ceramic
- radiation plate
- ceramic laminate
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 230000005855 radiation Effects 0.000 claims description 39
- 239000000919 ceramic Substances 0.000 claims description 26
- 238000006073 displacement reaction Methods 0.000 claims description 11
- 239000000463 material Substances 0.000 claims description 6
- 238000005452 bending Methods 0.000 description 5
- 238000006243 chemical reaction Methods 0.000 description 4
- HFGPZNIAWCZYJU-UHFFFAOYSA-N lead zirconate titanate Chemical compound [O-2].[O-2].[O-2].[O-2].[O-2].[Ti+4].[Zr+4].[Pb+2] HFGPZNIAWCZYJU-UHFFFAOYSA-N 0.000 description 3
- 230000003014 reinforcing effect Effects 0.000 description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 230000008878 coupling Effects 0.000 description 2
- 238000010168 coupling process Methods 0.000 description 2
- 238000005859 coupling reaction Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 229910000838 Al alloy Inorganic materials 0.000 description 1
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 229910010293 ceramic material Inorganic materials 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 230000001568 sexual effect Effects 0.000 description 1
- 238000010008 shearing Methods 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 239000004332 silver Substances 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- 239000010936 titanium Substances 0.000 description 1
- 238000002604 ultrasonography Methods 0.000 description 1
Landscapes
- Transducers For Ultrasonic Waves (AREA)
Description
（産業上の利用分野）
本発明は、水中においてハイパワーで超音波を
送波することのできる中心軸に対して無指向性の
圧電トランスジユーサに係わるものである。
（従来の技術）
従来、水中において中心軸に対して無指向性の
高効率ハイパワー超音波トランスジユーサとし
て、第３図に示すような円筒状圧電トランスジユ
ーサが知られている。このトランスジユーサはジ
ルコンチタン酸鉛系圧電セラミツクスでできてお
り、円筒の内外面に銀焼き付け電極が施され、内
厚方向に分極がなされている。この円筒状トラン
スジユーサは横効果の径拡がり振動モードが用い
られ、第３図の矢印で示すように振動子、指向性
は中心軸０−0′に対して無指向性となる。
（発明が解決しようとする問題点）
上記円筒状圧電トランスジユーサは径拡がり振
動モードで動作するため、円筒の内厚の中心を基
準とした直径ｄと共振周波数frとは反比例の関係
にあり、このトランスジユーサに用いられる圧電
セラミツクスの音速をClとすればfrは
fr＝Cl／πd (1)
で与えられる。即ち、共振周波数が２分の１、３
分の１、４分の１になれば、直径はそれぞれ２
倍、３倍、４倍となる。
従つて、ある所望の共振周波数を有する円筒状
圧電トランスジユーサの設計をする場合、直径が
決まつてしまうと他の設計パラメータは圧電セラ
ミツクスの音速Clだけとなる。しかしながら圧電
セラミツクス材料として、電気機械結合係数の大
きなジルコンチタン酸鉛系圧電セラミツクスが現
在のところ最高の材料でありこの音速は2800〜
3300m／sec程度でほとんど材料による差はない。
即ち、円筒状圧電トランスジユーサの小型化をは
かろうとする場合に、圧電セラミツクスの音速だ
けで寸法が決まつてしまうことから一定の限界が
あつた。また、よりハイパワー化をはかろうとす
ると、圧電セラミツクスの引つ張り応力に対する
強度は圧縮応力に対する強度の10分の１以下と小
さいため、圧電セラミツクスのこのような特殊な
材料強度からくる一定の限界があつた。
本発明は小型でハイパワー送波が可能であり、
高い電気音響交換効率を有する無指向性超音波ト
ランスジユーサを実現することにある。
（問題を解決するための手段）
本発明は、撓み変形が可能な矩形状の音響放射
板が正ｎ角形をなすように配列されたｎ個の音響
放射板と、前記正ｎ角形に配列されたｎ個の音響
放射板の中心に配置される正ｎ角形の剛い柱体
と、さらに前記各音響放射板と前記柱体との間に
内部に貫通孔のある圧電セラミツク積層体を配
し、前記貫通孔を通して、圧電セラミツク積層体
に圧縮応力を加えるボルトを設ける。そして前記
ボルトと前記音響整合板との接点、圧電セラミツ
ク積層体から突き出た高強度材からなる首部と前
記音響整合板との接点の両接点をてこの腕とし
て、てこの原理により前記音響放射板外縁部の振
動変位を大きくしたことを特徴とする水中超音波
トランスジユーサである。
（作用）
本発明のトランスジユーサは、音響放射板を正
ｎ角形をなるように放射状にｎ個配し同相で駆動
され、中心軸に対して従来の円筒状圧電トランス
ジユーサと同じく無指向性のトランスジユーサで
ある。本発明のトランスジユーサでは、圧電セラ
ミツク積層体とボルトの間に生ずる剪断力を積極
的に利用し、音響放射板に剛体回転を伴う屈曲振
動を励振させることにより、音響放射板の並進変
位と前記屈曲振動を伴せた形で効率良く音響放射
を行うことを特徴としている。
本発明に従つた水中超音波トランスジユーサを
第１図ａ，ｂに示す。第１図ａは平面図、第１図
ｂは平面図ａの一点鎖線Ａ−A′における断面図
を示す。第１図において、１１は屈曲振動を行う
音響放射板、１２は角柱、１３は圧電セラミツク
積層体、１４はボルト、１５は圧電セラミツク積
層体に生じた変位を音響放射板１１に伝えるヒン
ジ（首部）である。次に本発明に従つたトランス
ジユーサの動作原理を第１図に基づいて説明す
る。音響放射板１１は圧電セラミツク積層体１３
が圧電的に伸びたときに前方に伸ばし出される。
しかしながら、ボルト１４は圧電的に伸ばされな
いので、圧電セラミツク積層体１３の伸びを妨げ
ようとする力が生ずる。この反力はボルト１４の
直径が大きいほど大きくなる。このようにして音
響放射板１１に剪断力が生じ、音響放射板が撓む
わけである。音響放射板１１が撓むと、圧電セラ
ミツク積層体より外側にある放射板部分と内側に
ある放射板部分では位相が互いに逆相となる。本
発明に従つたトランスジユーサでは、音響放射板
の中央部と外縁部で振動変位の位相が逆相となつ
ても、この音響放射板１１の外縁部分の媒質排除
量（体積速度）が、音響放射板１１の内側部分の
媒質排除量より圧倒的に大きければ、全体として
の媒質排除量は相当なものになる。さらに本音響
放射板１１はこの他に圧電セラミツク積層体の伸
びによる剛体並進変位が加わるため、最終的には
破線ａ−a′からｂ−b′のように変位を行い、媒質
排除能力は一層向上するわけである。
以上、本発明に従つたトランスジユーサの動作
原理の概略について述べたが屈曲変位拡大機構
は、ボルト１４と音響放射板１１との接点、圧電
セラミツク積層体１３から突きでた高強度材料
（たとえば鉄、チタン）からなるヒンジ１５との
接点、つまりこの二つの接点の間をてこの腕とし
ててこの原理を用いている。従つて、音響放射板
１１の外縁部で振動変位を著しく拡大することが
できる。なおヒンジ１５は必ずしも必要でない。
このような本発明では、媒質排除量が増やせば
音響放射も増大することにより、高効率ハイパワ
ーのトランスジユーサを達成することができる。
尚、長さが大きな音響放射板を本トランスジユー
サに用いる場合、外縁部分において第２図に示す
ような補強部２１を設けると、音響放射板の剛体
回転モードにおける剛性が増しさらに慣性質量も
増大するので低周波小型化に大いに寄与すること
は言うまでもない。第２図ａは音響放射板１１の
平面図、ｂは正面図である。
従来の円筒状トランスジユーサでは、トランス
ジユーサの直径が決まると一意的に共振周波数が
決まつてしまうため、小型化をはかることが困難
であつたが、本発明に従つたトランスジユーサで
は、音響放射板に回転慣性が備わつており、小型
のトランスジユーサを得ようとする場合には、ヒ
ンジ間隔を音響放射板の数分の１に小さくとり、
あるいはまた第２図に示したような補強部を設け
ることにより、容易に実現することができる。
（実施例）
本発明の一実施例として第１図に示す水中超音
波トランスジユーサについて説明する。第１図に
示すトランスジユーサは外径寸法が11.5cmで高さ
は12cmである。圧電セラミツク積層体１３の圧電
セラミツクスとして電気機械結合係数k33が0.61、
比誘電率ε33Ｔ／ε0が1080のジルコンチタン酸鉛
系セラミツクスが用いられた。音響放射板１１に
Al合金、柱体１２にステンレススチール、ボルト
１４にCr−Mo剛、ヒンジ１５に同じくCr−Mo
剛を用いた。このトランスジユーサをゴムブーツ
で被覆し水密を保持して、電気音響変換効率、比
帯域幅の測定を行い、結果を同一外形寸法の円筒
状トランスジユーサと比較して第１表に示す。電
気音響変換効率と比帯域幅がともに改善されてい
るのが判かる。また同じ共振周波数の従来の円筒
状トランスジユーサと比べると体積で約半分以下
の小型になる。
(Industrial Application Field) The present invention relates to a piezoelectric transducer that is omnidirectional with respect to its central axis and is capable of transmitting high-power ultrasonic waves underwater. (Prior Art) A cylindrical piezoelectric transducer as shown in FIG. 3 has been known as a highly efficient, high-power ultrasonic transducer that is omnidirectional with respect to a central axis underwater. This transducer is made of piezoelectric ceramic based on lead zirconium titanate, and has silver baked electrodes on the inner and outer surfaces of the cylinder, and is polarized in the direction of the inner thickness. This cylindrical transducer uses a transverse effect radial expansion vibration mode, and as shown by the arrow in FIG. 3, the transducer has non-directionality with respect to the central axis 0-0'. (Problem to be Solved by the Invention) Since the above-mentioned cylindrical piezoelectric transducer operates in a diameter-expanding vibration mode, the diameter d with respect to the center of the inner thickness of the cylinder and the resonant frequency f r are inversely proportional to each other. If the sound speed of the piezoelectric ceramic used in this transducer is C l , f r is given by f r = C l /π d (1). That is, the resonance frequency is 1/2, 3
If it becomes 1/4 and 1/4, the diameter will be 2 respectively.
It becomes double, triple, quadruple. Therefore, when designing a cylindrical piezoelectric transducer having a certain desired resonant frequency, once the diameter is determined, the only other design parameter is the sound speed C l of the piezoelectric ceramic. However, as a piezoelectric ceramic material, lead zirconium titanate-based piezoelectric ceramics, which have a large electromechanical coupling coefficient, are currently the best material, and the sound velocity is 2800 ~
There is almost no difference depending on the material at around 3300m/sec.
That is, when attempting to miniaturize a cylindrical piezoelectric transducer, there is a certain limit because the size is determined only by the sound velocity of piezoelectric ceramics. In addition, when trying to achieve higher power, piezoelectric ceramics' strength against tensile stress is less than one-tenth of its strength against compressive stress, so piezoelectric ceramics have a certain level of strength due to its special material strength. I've reached my limit. The present invention is compact and capable of high power transmission,
The object of the present invention is to realize an omnidirectional ultrasonic transducer with high electroacoustic exchange efficiency. (Means for Solving the Problem) The present invention provides n acoustic radiation plates in which rectangular sound radiation plates capable of flexural deformation are arranged in a regular n-gon shape, and n acoustic radiation plates arranged in the regular n-gon shape. A regular n-gonal rigid column is arranged at the center of the n acoustic radiation plates, and a piezoelectric ceramic laminate having a through hole inside is arranged between each of the acoustic radiation plates and the column. , a bolt is provided through the through hole to apply compressive stress to the piezoelectric ceramic laminate. Then, by using the contact point between the bolt and the acoustic matching plate, and the contact point between the neck made of a high-strength material protruding from the piezoelectric ceramic laminate and the acoustic matching plate as lever arms, the acoustic radiation plate is This is an underwater ultrasonic transducer characterized by a large vibration displacement at the outer edge. (Function) The transducer of the present invention has n acoustic radiation plates arranged radially in a regular n-gon shape and driven in the same phase, and is non-directional with respect to the central axis like the conventional cylindrical piezoelectric transducer. She is a sexual transducer. In the transducer of the present invention, the shear force generated between the piezoelectric ceramic laminate and the bolts is actively utilized to excite the acoustic radiation plate to bending vibration accompanied by rigid body rotation, thereby reducing the translational displacement of the acoustic radiation plate. It is characterized by efficient acoustic radiation accompanied by the bending vibration. An underwater ultrasonic transducer according to the invention is shown in FIGS. 1a and 1b. FIG. 1a shows a plan view, and FIG. 1b shows a sectional view taken along the dashed line A-A' in the plan view a. In FIG. 1, 11 is an acoustic radiation plate that performs bending vibration, 12 is a prism, 13 is a piezoelectric ceramic laminate, 14 is a bolt, and 15 is a hinge (neck part) that transmits the displacement generated in the piezoelectric ceramic laminate to the acoustic radiation plate 11. ). Next, the principle of operation of the transducer according to the present invention will be explained based on FIG. The acoustic radiation plate 11 is a piezoelectric ceramic laminate 13
When stretched piezoelectrically, it is stretched forward.
However, since the bolt 14 is not piezoelectrically stretched, a force is generated which tends to prevent the piezoceramic laminate 13 from stretching. This reaction force increases as the diameter of the bolt 14 increases. In this way, a shearing force is generated in the acoustic radiation plate 11, causing the acoustic radiation plate to bend. When the acoustic radiation plate 11 is bent, the phases of the radiation plate portion outside the piezoelectric ceramic laminate and the radiation plate portion inside the piezoelectric ceramic laminate become opposite to each other. In the transducer according to the present invention, even if the phase of the vibration displacement is opposite between the central part and the outer edge of the acoustic radiation plate 11, the amount of medium displacement (volume velocity) at the outer edge of the acoustic radiation plate 11 is If it is overwhelmingly larger than the amount of medium removed from the inner portion of the acoustic radiation plate 11, the amount of medium removed as a whole will be considerable. Furthermore, since this acoustic radiation plate 11 is subjected to rigid body translational displacement due to the elongation of the piezoelectric ceramic laminate, it will ultimately be displaced as shown by the broken line a-a' to b-b', and the medium expulsion ability will be further improved. It will improve. The outline of the operating principle of the transducer according to the present invention has been described above, and the bending displacement magnification mechanism consists of a contact point between the bolt 14 and the acoustic radiation plate 11, a high-strength material protruding from the piezoelectric ceramic laminate 13 (for example, The lever principle is used by using the contact point with the hinge 15 made of (iron, titanium), that is, the gap between these two contact points as a lever arm. Therefore, the vibration displacement at the outer edge of the acoustic radiation plate 11 can be significantly expanded. Note that the hinge 15 is not necessarily required. According to the present invention, as the amount of medium excluded increases, the acoustic radiation also increases, so that a highly efficient and high power transducer can be achieved.
In addition, when a long acoustic radiation plate is used in this transducer, providing a reinforcing portion 21 as shown in FIG. It goes without saying that this greatly contributes to miniaturization of low frequency frequencies. FIG. 2a is a plan view of the acoustic radiation plate 11, and FIG. 2b is a front view. With conventional cylindrical transducers, the resonant frequency is uniquely determined once the diameter of the transducer is determined, making it difficult to reduce the size of the transducer, but the transducer according to the present invention , the acoustic radiating plate has rotational inertia, and when trying to obtain a small transducer, the hinge interval is made small to a fraction of the acoustic radiating plate.
Alternatively, this can be easily realized by providing a reinforcing portion as shown in FIG. (Example) An underwater ultrasonic transducer shown in FIG. 1 will be described as an example of the present invention. The transducer shown in Figure 1 has an outer diameter of 11.5 cm and a height of 12 cm. The piezoelectric ceramic of the piezoelectric ceramic laminate 13 has an electromechanical coupling coefficient k 33 of 0.61,
Lead zirconium titanate ceramics having a dielectric constant ε 33 T/ε 0 of 1080 was used. On the acoustic radiation plate 11
Al alloy, column 12 is stainless steel, bolt 14 is Cr-Mo rigid, hinge 15 is also Cr-Mo
I used Tsuyoshi. This transducer was covered with a rubber boot to keep it watertight, and the electroacoustic conversion efficiency and specific bandwidth were measured, and the results are shown in Table 1 in comparison with a cylindrical transducer of the same external dimensions. It can be seen that both the electroacoustic conversion efficiency and the specific bandwidth are improved. Furthermore, compared to a conventional cylindrical transducer with the same resonant frequency, the transducer is smaller in volume, about half or less.
【表】
なお音響放射板はその面積はこれを円形にした
ときその直径がヒンジの約３倍から10倍程度が望
ましい。また音響放射板の屈曲振動の周波数は並
進振動の周波数の約0.5倍から1.5倍程度が望まし
い。
（発明の効果）
以上述べた如く本発明に従つたトランスジユー
サでは、音響放射を行う音響放射板の並進変位の
みならず屈曲変形に伴う剛体回転変位を積極的に
利用しているため、電気音響変換効率の優れたト
ランスジユーサである。また従来の同じ共振周波
数の円筒状トランスジユーサに比べて著しい小型
化を達成することができる。[Table] It is preferable that the area of the acoustic radiation plate is approximately 3 to 10 times the diameter of the hinge when it is made into a circle. Further, the frequency of the flexural vibration of the acoustic radiation plate is preferably about 0.5 to 1.5 times the frequency of the translational vibration. (Effects of the Invention) As described above, the transducer according to the present invention actively utilizes not only the translational displacement of the acoustic radiation plate that radiates sound, but also the rotational displacement of the rigid body accompanying bending deformation. This is a transducer with excellent acoustic conversion efficiency. Further, it is possible to achieve a significant reduction in size compared to a conventional cylindrical transducer having the same resonant frequency.
第１図ａ，ｂは本発明に従つた水中超音波トラ
ンスジユーサの例を示す図でａは平面図、ｂは断
面図、第２図ａ，ｂは本発明のトランスジユーサ
に使用される音響放射板の一例を示す図でａは平
面図、ｂは正面図、第３図は従来の円筒状圧電ト
ランスジユーサである。
図において、１１は音響放射板、１２は柱体、
１３は圧電セラミツク積層体、１４はボルト、１
５はヒンジ、２１は補強部、３０は円筒状圧電セ
ラミツクトランスジユーサ。
1a and 1b are views showing an example of an underwater ultrasonic transducer according to the present invention, in which a is a plan view, b is a sectional view, and FIGS. 2a and 2b are views showing an example of an underwater ultrasound transducer according to the present invention. In the drawings, a is a plan view, b is a front view, and FIG. 3 is a conventional cylindrical piezoelectric transducer. In the figure, 11 is an acoustic radiation plate, 12 is a column,
13 is a piezoelectric ceramic laminate, 14 is a bolt, 1
5 is a hinge, 21 is a reinforcing portion, and 30 is a cylindrical piezoelectric ceramic transducer.
Claims (1)
角形をなすように配列されたｎ個の音響放射板
と、前記正ｎ角形に配列されたｎ個の音響放射板
の中心に配置される正ｎ角形の剛い柱体と、さら
に前記各音響放射板と前記柱体との間に配置され
る内部に貫通孔のある圧電セラミツク積層体と、
前記圧電セラミツク積層体に設けられた貫通孔を
通して、圧電セラミツク積層体に圧縮応力を加え
るボルトとを備え、ボルトと前記音響放射板との
接合部、圧電セラミツク積層体又は該積層体から
突き出た高強度材からなるヒンジと前記音響放射
板との接合部の両接合部をてこの腕として、てこ
の原理により前記音響放射板外縁部の振動変位を
生じせしめることを特徴とする水中超音波トラン
スジユーサ。1 The rectangular acoustic radiation shape that can be deflected is positive n
n acoustic radiation plates arranged in a rectangular shape, a regular n-gon shaped rigid column disposed at the center of the n acoustic radiation plates arranged in a regular n-gon shape, and each of the acoustic radiation plates a piezoelectric ceramic laminate having a through hole inside, disposed between the radiation plate and the pillar;
a bolt that applies compressive stress to the piezoelectric ceramic laminate through a through hole provided in the piezoelectric ceramic laminate; An underwater ultrasonic transducer characterized in that both joints of a hinge made of a strength material and the acoustic radiation plate are used as lever arms, and vibration displacement of the outer edge of the acoustic radiation plate is caused by a lever principle. Yusa.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1944586A JPS62176397A (en) | 1986-01-30 | 1986-01-30 | Non-directional underwater ultrasonic transducer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1944586A JPS62176397A (en) | 1986-01-30 | 1986-01-30 | Non-directional underwater ultrasonic transducer |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS62176397A JPS62176397A (en) | 1987-08-03 |
| JPH0441879B2 true JPH0441879B2 (en) | 1992-07-09 |
Family
ID=11999505
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1944586A Granted JPS62176397A (en) | 1986-01-30 | 1986-01-30 | Non-directional underwater ultrasonic transducer |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS62176397A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2658363B2 (en) * | 1989-03-13 | 1997-09-30 | 日本電気株式会社 | Transducer for sonar |
| JP5387293B2 (en) | 2009-09-29 | 2014-01-15 | 日本電気株式会社 | Acoustic transducer |
| JP5445323B2 (en) | 2010-05-17 | 2014-03-19 | 日本電気株式会社 | Acoustic transducer |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS49129492A (en) * | 1973-04-11 | 1974-12-11 | ||
| JPS6118299A (en) * | 1984-07-04 | 1986-01-27 | Nec Corp | Langevin vibrator tightened with bolt |
-
1986
- 1986-01-30 JP JP1944586A patent/JPS62176397A/en active Granted
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS49129492A (en) * | 1973-04-11 | 1974-12-11 | ||
| JPS6118299A (en) * | 1984-07-04 | 1986-01-27 | Nec Corp | Langevin vibrator tightened with bolt |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS62176397A (en) | 1987-08-03 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4706230A (en) | Underwater low-frequency ultrasonic wave transmitter | |
| US4672591A (en) | Ultrasonic transducer | |
| US4072871A (en) | Electroacoustic transducer | |
| JPH0431480B2 (en) | ||
| US5546361A (en) | Directional electro-acoustic transducers comprising a sealed sell consisting of two portions | |
| JPH0441879B2 (en) | ||
| JP2985509B2 (en) | Low frequency underwater transmitter | |
| US5515343A (en) | Electro-acoustic transducers comprising a flexible and sealed transmitting shell | |
| US6298012B1 (en) | Doubly resonant push-pull flextensional | |
| JPH02309799A (en) | Transmitter-receiver | |
| JPS6149670A (en) | Cantilever beam-shaped supersonic twisted elliptical vibrator | |
| JPH0514512B2 (en) | ||
| JP2006005403A (en) | Ultrasonic transmitter-receiver | |
| JPS62176399A (en) | Underwater ultrasonic transducer | |
| JPS6143897A (en) | Low frequency underwater ultrasonic transmitter | |
| JPS6143896A (en) | Low frequency underwater ultrasonic transmitter | |
| JPS61181299A (en) | Low frequency underwater ultrasonic wave transmitter | |
| JPS61133883A (en) | Low frequency underwater ultrasonic wave transmitter | |
| JPH047880B2 (en) | ||
| JPH0511711B2 (en) | ||
| JPH0446518B2 (en) | ||
| JP4911691B2 (en) | Transducer | |
| JPS6143098A (en) | Low frequency underwater ultrasonic transmitter | |
| JP2626026B2 (en) | Transducer | |
| JPH0511719B2 (en) |