US3736555A - Electroacoustic transducers - Google Patents
Electroacoustic transducers Download PDFInfo
- Publication number
- US3736555A US3736555A US00173476A US3736555DA US3736555A US 3736555 A US3736555 A US 3736555A US 00173476 A US00173476 A US 00173476A US 3736555D A US3736555D A US 3736555DA US 3736555 A US3736555 A US 3736555A
- Authority
- US
- United States
- Prior art keywords
- transducer
- tubular
- elements
- plate member
- recess
- 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
- 239000000919 ceramic Substances 0.000 claims description 10
- 239000004020 conductor Substances 0.000 claims description 10
- 239000000463 material Substances 0.000 claims description 10
- 230000005855 radiation Effects 0.000 abstract description 7
- 238000010276 construction Methods 0.000 description 3
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 1
- 238000003491 array Methods 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 229920001971 elastomer Polymers 0.000 description 1
- 239000002360 explosive Substances 0.000 description 1
- 230000013011 mating Effects 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 230000008520 organization Effects 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 229920002635 polyurethane Polymers 0.000 description 1
- 239000004814 polyurethane Substances 0.000 description 1
- 230000035939 shock Effects 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
Images
Classifications
-
- 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
- B06B1/0607—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 multiple elements
- B06B1/0622—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 multiple elements on one surface
- B06B1/0633—Cylindrical array
Definitions
- My invention relates to electroacoustic transducers, and more particularly to transducers which operate under water, for sonar and similar applications. My invention is particularly useful for transducers operating in either the higher audible frequency region or the ultrasonic frequency region.
- Prior art underwater transducers for producing a directional sound radiation pattern have employed an array of inertial mass loaded, vibrating pistons, driven by magnetostrictive or piezoelectric transducer means.
- One type of these transducers generates vibratory forces between an inertial mass and a sound radiating piston, such as is illustrated in US. Pat. No. 3,328,751.
- Another type of prior art directional underwater transducer employs longitudinal resonating electromechanical transducer elements, such as is illustrated in U.S. Pat. No. 2,427,062.
- the vibrating, sound radiating mass of these prior art piston" type transducers have a relatively large inertia. This inertia, in turn, limited the band width of the frequency-response characteristics. Thus. as transmitters, these transducers are limited because of the inherently high mechanical Q of the vibrating system.
- a primary object of my invention is to provide a directional underwater electroacoustic transducer having a relatively low vibrating mass, as compared to prior art structures.
- a related object is to achieve a relatively broad band of frequency-response, with high efficiency.
- Another object of my invention is to provide a directional underwater electroacoustic transducer which utilizes the radiation from an array of cylindrical transducer elements.
- Still another object of my invention is to provide a low-cost, high efficiency underwater transducer which has a low mechanical Q, with a resulting broad band response.
- Yet another object of my invention is to provide a low-cost, rugged transducer structure capable of with standing underwater explosive shock.
- a rugged, low-cost transducer used in a multiple array, to provide a greater sonic power output.
- the transducers are cylindrical shell elements which are partially recessed in a rigid baffle plate or housing structure. The only radiation from the transducer takes place from the exposed parts of the cylindrical shell (i.e., not the part recessed in the baffle).
- the inertia of the transducer is reduced, as compared to the piston type, yet a high efficiency is maintained, with a low Q, broad band response.
- FIG. 1 is a plan view illustrating one particular embodiment of my invention in which a number of cylindrical transducer elements are arranged to provide a piston-like radiating array, to achieve a directional pattern;
- FIG. 2 is a cross-sectional view taken along the line 2--2 of FIG. 1;
- FIG. 3 is a plan view of another embodiment of my invention, in which a plurality of cylindrical transducer elements are arranged in a linear array of piston-like radiating surfaces;
- FIG. 4 is a cross-sectional view taken along the line 4-4 of FIG. 3.
- a rigid plate member 10 might be made from steel, for example, or from any other suitable rigid material.
- a plurality of cylindrical transducer elements 14 may be polarized ceramic piezoelectric cylinders, having electrode surfaces on both the inside and outside walls of the cylinders, as known in the art. Two or more of these transducer elements are mounted in the recesses 13.
- a thin layer of low acoustic impedance material 17, such as corprene, is employed as a liner between the surfaces of thexrecessed semi-circular grooves 13 and the outside peripheral surfaces of the ceramic cylinders 14.
- the cylindrical transducer elements are assembled so that approximately 50 percent of the surface remains above the front face 12 of the rigid plate 10.
- the other 50 percent is recessed in the grooves 13. If the linear dimensions of the plate member 10 are greater than one wavelength of sound, generated at the operating frequency, the plate 10 acts as a large rigid baffle. A mirror image of the exposed top half of the cylinders is effectively created by the plate 10.
- a waterproof cable 18 has an internal conductor 19 connected to the outer electrode surfaces of the transducers by means of a conductor 20.
- Another internal cable conductor 21 is connected to the inner electrodes of the transducers by means of a conductor 22.
- a sound transparent, waterproof material 23 is sealed to the front surface 12 of the rigid plate member 10.
- the material 23 protectively encloses the transducer element assembly to enable an operation of the transducer in an underwater environment.
- the waterproof material 23 may be any suitable compound, which is similar to molded rubber or to a waterproof sound conducting material, such as polyurethane.
- An external A.C. source S is connected through the cable 18 to drive the transducers.
- the surface of the transducer elements 14 executes radial vibrations
- the structure illustrated in FIG. 1 results in a composite transducer having an effective piston radiating surface which is equivalent to the projected area of the transducer element array. If the plate member 10 has width and length dimensions exceeding approximately one wavelength of the sound being generated at the highest frequency of operation, the transducer generates a directional beam of sound radiated from the front side of the assembly. The sound radiated from the back of the structure (i.e., from the back of plate 10) is reduced. The beam angle gets progressively smaller as the size of plate 10 increases relative to the wavelength and as the total number of transducer elements increases in the assembled array.
- FIGS. 3 and 4 Another type of construction that embodies the same principles is shown in FIGS. 3 and 4.
- the plate member 10, of FIG. 2 is replaced by an elongated plate 31 having a funnel or channel cross-section which is constructed in the form illustrated in FIG. 4.
- a number of cylindrical ceramic transducers 32 are assembled as a linear array, with a portion of the outside surface of the cylinders mounted in a semi-circular recess 33 at the root of the funnel or channel.
- a corprene liner 34 is preferably placed between the outer surfaces of the ceramic cylinders 32 and the mating contoured surface 33 of the plate 31.
- the inner and outer electrode surfaces of the ceramic cylinders 32 are interconnected by wires 37, 38, and the electrical terminals are then connected to the internal conductors of an underwater cable 35.
- a sound transparent waterproof material 36 is sealed to the front of the funnel or channel surface of the plate structure 31.
- This waterproof covering serves the same function as the material 23, shown in FIG. 2.
- the transducer cylinders 32 are preferably arranged so that approximately one-half of the outer cylinder is shielded by the corprene liner 34, and the other half of the surface is exposed for radiating sound through the encapsulating material 36.
- the flared sides of the flange plate 31 are here shown as being set at an angle which is less than 180. This disclosure is selected as illustrative of the case where the horizontal radiation beam angle from the transducer is somewhat sharper than it would be if the flanged portions of the plate 31 were formed at an angle of 180.
- the plate member 31 acts as a large rigid baffle.
- the flare of plate 31 increases the ratio of acoustic energy radiated from the front side of the assembly, rel ative to the radiation which spills over and around to the back of the transducer assembly.
- transducer assembly has been given as using ceramic cylinders for the transducer elements.
- the cylinders 14 and 32 could be replaced, for example, by magnetostrictive nickel tubes with a toroidal winding around the periphery of the cylindrical shells. This structure operates as a magnetostrictive vibrator without changing the principle of my invention.
- the preferred arrangement is achieved when 50 percent of the vibrating cylindrical surface is embedded in the rigid baffle.
- the inventive transducer is also operative if either more or less than 50 percent of the surface is embedded into the recessed surface of the baffle plate.
- the advantages of the described structure is that a more economical directional array of transducers can be produced, as compared with the cost of similar conventional transducer arrays, which utilize mass loaded vibrating pistons, for example.
- the walls of the cylinders form the total vibrating diaphragm, and they are much lighter than a corresponding array of comparable vibrating pistons.
- the band width of the response-frequency characteristic of the inventive transducer can be made greater than the band width of the conventional transducer.
- any suitable and convenient array configuration of cylindrical elements may be used to achieve any desired beam pattern.
- the diameter of the cylinders is selected to place resonance near the center point of the frequency range of operation.
- the wall thickness of the cylindrical transducer elements is selected to control the transducer band width.
- An electroacoustic transducer comprising a rigid plate member having front and rear surfaces with at least one concave groove-like recess having a semicircular cross section formed within said front surface, said recess having an axis of symmetry lying parallel to said front surface, at least one cylindrical tubular transducer element having a longitudinal axis and an external surface with a circular cross section co-axially positioned around said longitudinal axis, said transducer element comprising means for executing radial vibrations of said surface when driven by electrical power from an alternating current source, said cylindrical transducer being mounted in said semi-circular concave recess with a first portion of said tubular surface being surrounded by walls of said recess and another portion of said surface being exposed above said front surface, electric conductor means for connecting said alternating current source to said transducer element, and waterproof sound transparent means sealed to said rigid plate member and waterproofingly covering the exposed surfaces of said transducer elements.
- transducer of claim 1 wherein there are a plurality of said concave recesses and a plurality of said transducer elements, each of said transducer elements being mounted within an associated slot, with the axes of the transducer elements parallel to the axes of the slots.
- transducer of claim 1 and a layer of pressure release material between the outer surface of the tubular transducer element and the surface of the concave groove within which the tubular element is mounted.
- transducer of claim 1 further characterized in that said transducer element is a polarized ceramic cylinder.
- transducer of claim 5 further characterized in that said transducer element is a polarized ceramic cylinder.
- transducer of claim 1 further characterized in that said transducer element is a magnetostrictive tube.
- transducer of claim 5 further characterized in that said transducer element is a magnetostrictive tube.
Abstract
Description
Claims (9)
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US17347671A | 1971-08-20 | 1971-08-20 |
Publications (1)
Publication Number | Publication Date |
---|---|
US3736555A true US3736555A (en) | 1973-05-29 |
Family
ID=22632200
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US00173476A Expired - Lifetime US3736555A (en) | 1971-08-20 | 1971-08-20 | Electroacoustic transducers |
Country Status (1)
Country | Link |
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US (1) | US3736555A (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5412182A (en) * | 1992-04-09 | 1995-05-02 | City Of Hope | Eddy current heating for hyperthermia cancer treatment |
US20110211424A1 (en) * | 2008-08-21 | 2011-09-01 | Industrial Research Limited | Acoustic Transducer for Swath Beams |
US20110298585A1 (en) * | 2010-06-08 | 2011-12-08 | Vodafone Holding Gmbh | Smart card and mobile communication device comprising the smart card |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2947969A (en) * | 1954-09-08 | 1960-08-02 | Harris Transducer Corp | Elongated electroacoustic transducer with integral reinforced mounting flanges |
US2989725A (en) * | 1953-06-30 | 1961-06-20 | Harry B Miller | Electroacoustic transducer |
US3070790A (en) * | 1959-12-30 | 1962-12-25 | Wilfred Roth | Acoustic transducers |
-
1971
- 1971-08-20 US US00173476A patent/US3736555A/en not_active Expired - Lifetime
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2989725A (en) * | 1953-06-30 | 1961-06-20 | Harry B Miller | Electroacoustic transducer |
US2947969A (en) * | 1954-09-08 | 1960-08-02 | Harris Transducer Corp | Elongated electroacoustic transducer with integral reinforced mounting flanges |
US3070790A (en) * | 1959-12-30 | 1962-12-25 | Wilfred Roth | Acoustic transducers |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5412182A (en) * | 1992-04-09 | 1995-05-02 | City Of Hope | Eddy current heating for hyperthermia cancer treatment |
US20110211424A1 (en) * | 2008-08-21 | 2011-09-01 | Industrial Research Limited | Acoustic Transducer for Swath Beams |
US9218799B2 (en) | 2008-08-21 | 2015-12-22 | Wassp Limited | Acoustic transducer for swath beams |
US20110298585A1 (en) * | 2010-06-08 | 2011-12-08 | Vodafone Holding Gmbh | Smart card and mobile communication device comprising the smart card |
US8730009B2 (en) * | 2010-06-08 | 2014-05-20 | Vodafone Holding Gmbh | Smart card and mobile communication device comprising the smart card |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: DELLORFANO, FRED M. JR. Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:STONELEIGH TRUST, THE;REEL/FRAME:005397/0016 Effective date: 19841223 Owner name: MASSA PRODUCTS CORPORATION, 80 LINCOLN STREET, HIN Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNORS:DONALD P. MASSA TRUST;CONSTANCE ANN MASSA TRUST *;GEORGIANA M. MASSA TRUST;AND OTHERS;REEL/FRAME:005395/0954 Effective date: 19841223 Owner name: MASSA PRODUCTS CORPORATION, 280 LINCOLN STREET, HI Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNORS:DONALD P. MASSA TRUST;CONSTANCE ANN MASSA TRUST;ROBERT MASSA TRUST;AND OTHERS;REEL/FRAME:005395/0971 Effective date: 19860612 Owner name: TRUSTEES FOR AND ON BEHALF OF THE D.P. MASSA TRUST Free format text: ASSIGN TO TRUSTEES AS EQUAL TENANTS IN COMMON, THE ENTIRE INTEREST.;ASSIGNORS:MASSA, DONALD P.;MASSA, CONSTANCE A.;MASSA, GEORGIANA M.;AND OTHERS;REEL/FRAME:005395/0942 Effective date: 19841223 Owner name: MASSA, DONALD P., COHASSET, MA Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:STONELEIGH TRUST, THE;REEL/FRAME:005397/0016 Effective date: 19841223 |