US2906991A - Transducer construction employin employing annular vibrators - Google Patents

Transducer construction employin employing annular vibrators Download PDF

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US2906991A
US2906991A US518316A US51831655A US2906991A US 2906991 A US2906991 A US 2906991A US 518316 A US518316 A US 518316A US 51831655 A US51831655 A US 51831655A US 2906991 A US2906991 A US 2906991A
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casing
annular
wall
vibratile
transducer
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US518316A
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Leon W Camp
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Bendix Aviation Corp
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Bendix Aviation Corp
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B06—GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS IN GENERAL
    • B06B—METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, e.g. FOR PERFORMING MECHANICAL WORK IN GENERAL
    • B06B1/00—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency
    • B06B1/02—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy
    • B06B1/06—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezoelectric effect or with electrostriction
    • B06B1/0644—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezoelectric effect or with electrostriction using a single piezoelectric element
    • B06B1/0655—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezoelectric effect or with electrostriction using a single piezoelectric element of cylindrical shape

Definitions

  • This invention relates to underwater transducers of the type employing one or more radially vibratile annular vibrators, the inner faces of which are in acoustic conductive relation with the water and the outer faces of which are acoustically insulated from the water. Certain features of the invention are also applicable to transducers in which the outer face of an annular vibrator is in contact with the water and the inner face is acoustically insulated from the water.
  • An object of the invention is to simplify the construction and improve the eiiiciency of transducers of the type mentioned.
  • a more specic object is to improve the acoustic insulation of the non-working surface of the annular vibrator.
  • Another specilic object is to provide a transducer construction permitting the use of free air or other gas as the acoustic insulating medium in contact with the inactive or non-working surface of an annular vibratile element.
  • each vibrator In transducers employing annular vibratile elements, as usually constructed, one end of each vibrator is closed by a wall of radically dilferent impedance from water to reiiect sound, and the other end is open so that the inner annular surface is communicated with the water. Since radially vibratile rings also radiate from their peripheral faces, the latter must be acoustically insulated from the water. Furthermore, when the rings are of ceramic materials having electrodes on their inner and outer walls, the walls must be electrically insulated from each other.
  • Acoustic and electrical insulation has been accomplished in the past by providing a sound-conductive liquid barrier (sound window) as the front wall of the transducer, iilling the transducer with an electrically insulating liquid having substantially the same acoustic properties as water, and surrounding the outer faces or walls of the annular vibrators with an acoustic insulating material, such as air cell rubber, Corprene, etc.
  • a sound-conductive liquid barrier sound window
  • an electrically insulating liquid having substantially the same acoustic properties as water
  • an acoustic insulating material such as air cell rubber, Corprene, etc.
  • the present invention eliminates the use of both the sound window and the solid insulating material by sealing between the ends of the annular vibrators and the casing so that the inner surfaces of the vibrators are exposed directly to the water, whereas the outer surfaces are separated from each other and from the casing by air space.
  • the seal must be of such a nature as to permit the radial vibration of the vibrators, and this condition is satisfied by employing a rubber O-ring positioned between each end of each vibrator and the adjacent end wall of the transducer casing.
  • Fig. l is a front end elevational view of a complete transducer in accordance with the invention employing seven annular vibratile elements.
  • Fig. 2 is a front end elevational view with the front wall removed.
  • Fig. 4 is an end view, showing a single annular transducer in accordance with the invention adapted to receive or transmit at its external cylindrical face.
  • Fig. S is a longitudinal section in the plane V--V of Fig. 4.
  • the transducer therein disclosed comprises a front wall 10a, a rear wall 10b, and a cylindrical lateral wall 10c, together defining a casing 10.
  • the front wall 10a and the rear wall 10b are rigidly secured in iixed spaced relations parallel to each other by a plurality of screws 11 which extend through apertures provided therefor in the front wall 10 and are threaded into the rear wall 10b.
  • Each screw 11 is surrounded by a rigid metal sleeve 12 which determines the spacing between the walls 10a and 10b when the screws are drawn up tight.
  • the peripheral wall 10c is so dimensioned as to be clamped tightly between the front and rear walls at the edges thereof.
  • a rubber seal 19 may be provided between the ends of the peripheral wall 10c and the front and rear walls 10a and 10b respectively.
  • the casing 10 contains an array of seven annular vibratile elements 13, each having flat parallel end walls 13a and 13b, respectively, a cylindrical inner wall 13C, and a cylindrical outer wall 13d.
  • Each element 13 has an inner electrode 13e on its inner cylindrical face 13e and an outer electrode 13]c on its outer cylindrical face 13d. Connection to the inner electrodes 13e may be made by connecting each electrode to the casing as by a pigtail 14.
  • the outer electrodes 13]c can be connected by leads to each other and to the central conductor 15a of a coaxial lead-in-cable 15, the outer conductor 15b of which is grounded to the casing 10.
  • Each element may be of an electromechanically sensitive material, such as barium titanate, which is capable of vibrating radially in response to electrical potential applied between the inner and outer electrodes 13e and 133, or, vice versa, is capable of generating a potential between said electrodes when vibration is induced mechanically.
  • an electromechanically sensitive material such as barium titanate
  • the present invention does not relate to any particular electromechanically-sensitive material, but rather to an assembly incorporating radially vibratile rings, regardless of the exact nature of the elements themselves.
  • each element 13 is sealed with respect to the front wall 10a by an O-ring 16 of rubber or other suitable elastomer mounted in an annular groove, either in the casing end wall 10a or the upper end wall 13a of the element. lt is usually easier to form the groove in the casing wall 10a, and such an arrangement is shown inFig. 3.
  • the lower end 13b of the vibratile element is similarly sealed with respect to the casing Wall 10b by an O-ring 17.
  • the front end wall 10a of the casing 10 is provided with seven apertures 18, each aligned with and substantially coextensive with the inner wall 13C of its associated vibratile element.
  • the interior surface or wall 13e of each vibratile element is in direct communication with water exterior of the casing, whereas the outside walls 13d of all the vibratile elements are acoustically isolated from each other and from the casing by a dead air space defined by the vibratile element and the casing.
  • This dead air space provides about the best possible acoustic insulation to acoustically insulate the outer surfaces of the vibratile elements.
  • thev posts 11 are positioned adjacent the; outerr sui-.facesl 13d off the; elements. lf3 and. are surrounded with tubes of yieldable material 2u" of such thickness as.: to: lightly contact: the, outer surfaces i3d of the; Vibratile elements. and thereby prevent any appreciable movement thereof away from their predetermined positions:v
  • a transducer having an array of vibratile element-s, as shown. in Figs. l, 2- and 3, is particularly usefui where itc i's. desired to; have directional properties; Le., to transmit or receive ⁇ sound. ⁇ most eiciently in a certain direction. However, there areoccasions where it is desirable to, transmit. or receive. sound. simultaneously in all horizontal directions..
  • a desirable form of transducer for this purpnse. isasinglefradially'vibratile annular element having its; outer cylindrical wall in. acousticl conductive relation. with; the) waterf and its inner wall. acoustically insulated'.V Such. an arrangement' in accordance wtih the presenti invention is.
  • a transducer foruse inliquids comprising: a radially vibratile annular element of electromechanically-sensitive materia-l having fiat parallel opposite end'. walls and inner and outer cylindrical walls; means associatedrwith said element fon electrically coupling it to an electric, circuit; casing means. defining with said annular element a closed air space. acoustically isolating the outer cylindrical wall of said element and including a pair of casing end walls juxtaposed tobutspaced from the respective end walls ofsaid element, and an elastomer sealing ring compressed between. each endwall of saidl annular element and the adjacent casing end wall for effecting a iluid seal ⁇ there- 4' of said end wallshas. an opening therethrough aligned with said element for acoustically. communicating the inner surface thereof with the exterior of said casing.
  • A- transducer in. which one ofV saidjuxtaposed endi walls. at. each. end of said element has an annular groove therein and saidi sealing ringf'is an Orring positioned partly in andpartly projecting from said groove".
  • Liquid-vibrating apparatus comprising: a radially vibratile annular: element of electromechanically-sensitive materialhaving-.at parallek opposite end faces, and inner' and' outer generally cylindricalA faces; means associated with saidelernent: for electrically coupling it to; an electric circuit; casing means for supporting said element for radial vibrationz and forming a liquid. barrien between the said inner and. outer cylindrical faces; thereon, said casing means comprising a pair of casing end walls juxtaposed tothe respective. end faces off said. element, each said end wall having-..a n. annular groove therein opposite and of less radial width. thangthe' associated endl face of said element;. an. elastomer sealing ring in each saidr groove.

Description

Sept. 29, 1959 L. w. cAMP 2,906,991
TRANSDUCER CONSTRUCTION EMPLOYING ANNULAR VIBRATORS Filed June 2'7, 1955 Ilia? INVENTOR. Leon W Camp /7 ATTORNEY 2,906,991 TRANSDUCER CONSTRUCTION EMPLOYING ANNULAR VIBRATORS Leon W. Camp, Glendale, Calif., assignor to Bendix Aviation Corporation, North Hollywood, Calif., a corporation of Delaware Application .lune 27, 1955, Serial No. 518,316 7 Claims. (Cl. 340-8) This invention relates to underwater transducers of the type employing one or more radially vibratile annular vibrators, the inner faces of which are in acoustic conductive relation with the water and the outer faces of which are acoustically insulated from the water. Certain features of the invention are also applicable to transducers in which the outer face of an annular vibrator is in contact with the water and the inner face is acoustically insulated from the water.
An object of the invention is to simplify the construction and improve the eiiiciency of transducers of the type mentioned.
A more specic object is to improve the acoustic insulation of the non-working surface of the annular vibrator.
Another specilic object is to provide a transducer construction permitting the use of free air or other gas as the acoustic insulating medium in contact with the inactive or non-working surface of an annular vibratile element.
Other more specific objects and features of the invention will appear from the description to follow.
In transducers employing annular vibratile elements, as usually constructed, one end of each vibrator is closed by a wall of radically dilferent impedance from water to reiiect sound, and the other end is open so that the inner annular surface is communicated with the water. Since radially vibratile rings also radiate from their peripheral faces, the latter must be acoustically insulated from the water. Furthermore, when the rings are of ceramic materials having electrodes on their inner and outer walls, the walls must be electrically insulated from each other. Acoustic and electrical insulation has been accomplished in the past by providing a sound-conductive liquid barrier (sound window) as the front wall of the transducer, iilling the transducer with an electrically insulating liquid having substantially the same acoustic properties as water, and surrounding the outer faces or walls of the annular vibrators with an acoustic insulating material, such as air cell rubber, Corprene, etc.
The present invention eliminates the use of both the sound window and the solid insulating material by sealing between the ends of the annular vibrators and the casing so that the inner surfaces of the vibrators are exposed directly to the water, whereas the outer surfaces are separated from each other and from the casing by air space. The seal must be of such a nature as to permit the radial vibration of the vibrators, and this condition is satisfied by employing a rubber O-ring positioned between each end of each vibrator and the adjacent end wall of the transducer casing.
A full understanding of the invention may be had from the following detailed descripion with reference to the drawing, in which:
Fig. l is a front end elevational view of a complete transducer in accordance with the invention employing seven annular vibratile elements.
Fig. 2 is a front end elevational view with the front wall removed.
States Patent ice Fig. 3 is an enlarged detail longitudinal section taken in the plane III-III of Fig. l.
Fig. 4 is an end view, showing a single annular transducer in accordance with the invention adapted to receive or transmit at its external cylindrical face.
Fig. S is a longitudinal section in the plane V--V of Fig. 4.
Referring to Figs. l, 2 and 3, the transducer therein disclosed comprises a front wall 10a, a rear wall 10b, and a cylindrical lateral wall 10c, together defining a casing 10. The front wall 10a and the rear wall 10b are rigidly secured in iixed spaced relations parallel to each other by a plurality of screws 11 which extend through apertures provided therefor in the front wall 10 and are threaded into the rear wall 10b. Each screw 11 is surrounded by a rigid metal sleeve 12 which determines the spacing between the walls 10a and 10b when the screws are drawn up tight. The peripheral wall 10c is so dimensioned as to be clamped tightly between the front and rear walls at the edges thereof. A rubber seal 19 may be provided between the ends of the peripheral wall 10c and the front and rear walls 10a and 10b respectively.
The casing 10 contains an array of seven annular vibratile elements 13, each having flat parallel end walls 13a and 13b, respectively, a cylindrical inner wall 13C, and a cylindrical outer wall 13d. Each element 13 has an inner electrode 13e on its inner cylindrical face 13e and an outer electrode 13]c on its outer cylindrical face 13d. Connection to the inner electrodes 13e may be made by connecting each electrode to the casing as by a pigtail 14. The outer electrodes 13]c can be connected by leads to each other and to the central conductor 15a of a coaxial lead-in-cable 15, the outer conductor 15b of which is grounded to the casing 10.
Each element may be of an electromechanically sensitive material, such as barium titanate, which is capable of vibrating radially in response to electrical potential applied between the inner and outer electrodes 13e and 133, or, vice versa, is capable of generating a potential between said electrodes when vibration is induced mechanically. However, the present invention does not relate to any particular electromechanically-sensitive material, but rather to an assembly incorporating radially vibratile rings, regardless of the exact nature of the elements themselves.
The upper end 13a of each element 13 is sealed with respect to the front wall 10a by an O-ring 16 of rubber or other suitable elastomer mounted in an annular groove, either in the casing end wall 10a or the upper end wall 13a of the element. lt is usually easier to form the groove in the casing wall 10a, and such an arrangement is shown inFig. 3. The lower end 13b of the vibratile element is similarly sealed with respect to the casing Wall 10b by an O-ring 17.
The front end wall 10a of the casing 10 is provided with seven apertures 18, each aligned with and substantially coextensive with the inner wall 13C of its associated vibratile element. Hence, the interior surface or wall 13e of each vibratile element is in direct communication with water exterior of the casing, whereas the outside walls 13d of all the vibratile elements are acoustically isolated from each other and from the casing by a dead air space defined by the vibratile element and the casing. This dead air space provides about the best possible acoustic insulation to acoustically insulate the outer surfaces of the vibratile elements.
Although the 0- rings 16 and 17 provide suicient freedom of movement to substantially unappreciably impede the acoustic vibration in radial mode of the vibrators 13, they offer substantial frictional resistance to large displacements of the elements from their desired positionsv in. alignment with. the, openings. 18. However,J
as additional precaution to. prevent such displacement of the annular elements, thev posts 11 are positioned adjacent the; outerr sui-.facesl 13d off the; elements. lf3 and. are surrounded with tubes of yieldable material 2u" of such thickness as.: to: lightly contact: the, outer surfaces i3d of the; Vibratile elements. and thereby prevent any appreciable movement thereof away from their predetermined positions:v
A transducer having an array of vibratile element-s, as shown. in Figs. l, 2- and 3, is particularly usefui where itc i's. desired to; have directional properties; Le., to transmit or receive` sound.` most eiciently in a certain direction. However, there areoccasions where it is desirable to, transmit. or receive. sound. simultaneously in all horizontal directions.. A desirable form of transducer for this purpnse. isasinglefradially'vibratile annular element having its; outer cylindrical wall in. acousticl conductive relation. with; the) waterf and its inner wall. acoustically insulated'.V Such. an arrangement' in accordance wtih the presenti invention is. shown in Figs..4. and 5.. It will be observed that the construction is` essentially the same as` that in Figs. 1,. 2. and 31, except'that. therev is only one radially vibratile annular element, and both Vof its ends are closed by casing plates. 25 and. 26 of.` substantially. the same diameter as the external diameter of the annular element 1'3., thev end plates having grooves therein.` and OS-.rings 16. and` 17 corresponding to the O-ring seals in Fig. 3. However, the twofendplates 25 and 26 are solid,wso. that they de'ne with the. element 1-3 a. closed cylindrical air space. which acoustically insulates the. inner wall 13C. Bolts 11, spacer sleeves 12, and locating sleeves 20 identical with those shown in Fig. 3 are employed inV Fig..4, but'they arepositioned within the annular element 13. so thaty they extend through the dead air space therein.
Although for thepurposeof` explaining the invention a particular embodiments thereof has been shown and described, obvious modifications will occur toV a `person skilled inthe art,A and I do not desire to be limited` to theexactfdetails shown and described.
I claim: v
1'. A transducer foruse inliquids comprising: a radially vibratile annular element of electromechanically-sensitive materia-l having fiat parallel opposite end'. walls and inner and outer cylindrical walls; means associatedrwith said element fon electrically coupling it to an electric, circuit; casing means. defining with said annular element a closed air space. acoustically isolating the outer cylindrical wall of said element and including a pair of casing end walls juxtaposed tobutspaced from the respective end walls ofsaid element, and an elastomer sealing ring compressed between. each endwall of saidl annular element and the adjacent casing end wall for effecting a iluid seal` there- 4' of said end wallshas. an opening therethrough aligned with said element for acoustically. communicating the inner surface thereof with the exterior of said casing.
3. A transducer according to claim l in which said casing means includes a plurality of rigid post members extending betweenv said end walls; of said casing through said, closed air space for rigidly supporting said casing end' Walls spaced, apart av distance slightly exceeding' the length of said annular element.
4. A- transducer according to: claim 3 in. which one ofV saidjuxtaposed endi walls. at. each. end of said element has an annular groove therein and saidi sealing ringf'is an Orring positioned partly in andpartly projecting from said groove". v
5. A transducer according to; claim 3 in which said post members are positioned adjacent said outer wall of said element and yieldable means supported by said posts and contacting relativelyA small areas. oi said outer wall for supporting' said annular Velement against lateral= displacement. A
6. Liquid-vibrating apparatus comprising: a radially vibratile annular: element of electromechanically-sensitive materialhaving-.at parallek opposite end faces, and inner' and' outer generally cylindricalA faces; means associated with saidelernent: for electrically coupling it to; an electric circuit; casing means for supporting said element for radial vibrationz and forming a liquid. barrien between the said inner and. outer cylindrical faces; thereon, said casing means comprising a pair of casing end walls juxtaposed tothe respective. end faces off said. element, each said end wall having-..a n. annular groove therein opposite and of less radial width. thangthe' associated endl face of said element;. an. elastomer sealing ring in each saidr groove.
of suchthickness; as; to1 projecty from the; groove against thev associatedflat end face of said element; means'rigidly.
supporting said end walls with respect to each other and:
inspacedrelation torsaid: element such asfto: slightly compress each. said/ ringLbetween the .bottom of its groovev and the. associated end face of said element, saidl rings constitutingthe solemeansaxially. supporting said element with. respect. to said.casing;means;. andmeans other than saidl elastomer rings for limitingi transverse. movement of saidrelement wtih. respect. to said casing end walls.
7*.. Apparatus accordingLto claim.. 6. in which said elastomer: rings. area-rings, and; saidi spacing between saidV endl walls'isisuchiastol slightly attensaid. G-.rings whereby they effect a uids seal between saidV end wallsV and said end faces of; said element' while olering. only slight between While permitting radial vibration of the element Y relative@ to said casing means.
'2'.` A'. transducer according to claim 1 in which one resstanceto. radial vibrationlof. said element. with respect to. saidfend walls.
ReferencesfCited-in; the leof this patent UNITED STATES, PATENTS Y 2,732,536. MillerA f Jan. 24;.17`956
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Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3056589A (en) * 1958-06-23 1962-10-02 Bendix Corp Radially vibratile ceramic transducers
US3074267A (en) * 1957-07-31 1963-01-22 Zeiss Jena Veb Carl Sheet testing devices
US3123798A (en) * 1964-03-03 Fish finder
US3222919A (en) * 1962-01-12 1965-12-14 Endevco Corp Mechanical impedance measuring system
US3341706A (en) * 1962-05-04 1967-09-12 Dresser Ind Apparatus for and method of terrestrial surveying
US3577021A (en) * 1969-01-29 1971-05-04 Honeywell Inc Piezoelectric transducer mounting apparatus
US3699508A (en) * 1970-08-05 1972-10-17 Dynamics Corp Massa Div Means for increasing the acoustic power output of underwater transducers
US3699507A (en) * 1970-08-05 1972-10-17 Dynamics Corp Massa Div Baffle structure for underwater transducer array
US4709359A (en) * 1982-06-28 1987-11-24 Magnovox Government And Industrial Electronics Company End weighted reed sound transducer
EP0492882A2 (en) * 1990-12-24 1992-07-01 General Electric Company Moment bender transducer drive
US5187982A (en) * 1991-04-26 1993-02-23 Cheng Chu Vibration controlled experimenting device provided with a motor with an imbalanced rotor
US5204844A (en) * 1990-12-24 1993-04-20 General Electric Company Moment bender transducer
US5239864A (en) * 1991-04-01 1993-08-31 The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration Dynamic tester for rotor seals and bearings
WO1996025831A1 (en) * 1995-02-17 1996-08-22 Bolt Beranek And Newman Inc. Underwater acoustic projector
US20090207696A1 (en) * 2006-12-04 2009-08-20 Lockhead Martin Corporation Hybrid transducer

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2732536A (en) * 1956-01-24 miller

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2732536A (en) * 1956-01-24 miller

Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3123798A (en) * 1964-03-03 Fish finder
US3074267A (en) * 1957-07-31 1963-01-22 Zeiss Jena Veb Carl Sheet testing devices
US3056589A (en) * 1958-06-23 1962-10-02 Bendix Corp Radially vibratile ceramic transducers
US3222919A (en) * 1962-01-12 1965-12-14 Endevco Corp Mechanical impedance measuring system
US3341706A (en) * 1962-05-04 1967-09-12 Dresser Ind Apparatus for and method of terrestrial surveying
US3577021A (en) * 1969-01-29 1971-05-04 Honeywell Inc Piezoelectric transducer mounting apparatus
US3699508A (en) * 1970-08-05 1972-10-17 Dynamics Corp Massa Div Means for increasing the acoustic power output of underwater transducers
US3699507A (en) * 1970-08-05 1972-10-17 Dynamics Corp Massa Div Baffle structure for underwater transducer array
US4709359A (en) * 1982-06-28 1987-11-24 Magnovox Government And Industrial Electronics Company End weighted reed sound transducer
EP0492882A2 (en) * 1990-12-24 1992-07-01 General Electric Company Moment bender transducer drive
US5204844A (en) * 1990-12-24 1993-04-20 General Electric Company Moment bender transducer
EP0492882A3 (en) * 1990-12-24 1993-08-25 General Electric Company Moment bender transducer drive
US5239864A (en) * 1991-04-01 1993-08-31 The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration Dynamic tester for rotor seals and bearings
US5187982A (en) * 1991-04-26 1993-02-23 Cheng Chu Vibration controlled experimenting device provided with a motor with an imbalanced rotor
AU654252B2 (en) * 1992-02-06 1994-10-27 Lockheed Martin Corporation Improved moment bender transducer
WO1996025831A1 (en) * 1995-02-17 1996-08-22 Bolt Beranek And Newman Inc. Underwater acoustic projector
US5673236A (en) * 1995-02-17 1997-09-30 Bbn Corporation Underwater acoustic projector
US20090207696A1 (en) * 2006-12-04 2009-08-20 Lockhead Martin Corporation Hybrid transducer
US7583010B1 (en) * 2006-12-04 2009-09-01 Lockheed Martin Corporation Hybrid transducer

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