CA1063710A - Electromagnetic transducer - Google Patents
Electromagnetic transducerInfo
- Publication number
- CA1063710A CA1063710A CA258,938A CA258938A CA1063710A CA 1063710 A CA1063710 A CA 1063710A CA 258938 A CA258938 A CA 258938A CA 1063710 A CA1063710 A CA 1063710A
- Authority
- CA
- Canada
- Prior art keywords
- air gap
- elements
- current conduction
- magnetic flux
- conduction means
- 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
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R9/00—Transducers of moving-coil, moving-strip, or moving-wire type
- H04R9/02—Details
- H04R9/04—Construction, mounting, or centering of coil
- H04R9/045—Mounting
-
- 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
- B06B1/04—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with electromagnetism
- B06B1/045—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with electromagnetism using vibrating magnet, armature or coil system
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K33/00—Motors with reciprocating, oscillating or vibrating magnet, armature or coil system
- H02K33/18—Motors with reciprocating, oscillating or vibrating magnet, armature or coil system with coil systems moving upon intermittent or reversed energisation thereof by interaction with a fixed field system, e.g. permanent magnets
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K35/00—Generators with reciprocating, oscillating or vibrating coil system, magnet, armature or other part of the magnetic circuit
- H02K35/04—Generators with reciprocating, oscillating or vibrating coil system, magnet, armature or other part of the magnetic circuit with moving coil systems and stationary magnets
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R9/00—Transducers of moving-coil, moving-strip, or moving-wire type
- H04R9/02—Details
- H04R9/025—Magnetic circuit
Abstract
Electromagnetic Transducer Abstract of the Invention An electromagnetic transducer wherein magnetic forces are transmitted via an armature that has an elongated regular, or serpentine, tubular shape, and that is positioned within the air gap of a tubular shaped magnetic rim type structure having the same general overall shape as the armature. When used as an electro-acoustic transducer, the armature is secured to the peripheral edge of a diaphram.
Description
BACKGROUND OF THE INVENTION
This invention pertains in general to electromagnetic ~ :
transducers, and, more particularly, to transducers for converting electrical energy into movements or sounds, and/or movements or sounds into electrical energy.
Electromagnetic transducers for converting movements or forces (such as sound) into electrical energy, or for converting electrical energy into movements or forces (such as sound), include an electrically-conductive movable element (armature) and a sta-tionary magnetic element (stator) for applying magnetic flux thereto. -Forces applied to the armature, as a result of magnetic flux vari-ations, convert electrical energy into movements, and in the case of a speaker, soundO Alternately, physical forces on the armature ~ ;
(such as in the case of microphones) oreate changes in the magnetic flux and generate electrical signals due to the movement of the ` -. ,~ . -~ . .
armature. ` -In the prior art speakers, the armature is located in a ; ~ `
magnetic field and is generally secured near the center of the diaphragm (speaker cone). The armature usually includes a coil that ,;,: ~
receives the electrical signals to be converted into soundu The high frequencies are generated on the center of the diaphragm while the intermediate and base frequencies are generated over the entire `~
,, surface of the coneO Such an arrangement has poor efficiency at ~ -high frequencies and, as a result, usually has a degraded high fre~
quency response.
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In order to obtain an improved high-frequency re~ponse, a small "tweeter" type speaker cone has been mounted within the center of the large speaker cone to get greater power output at high frequencies. Other arrangements include separate base and tweeter speakerss electrically interconnected with cross-over networks to provide an overall high-fidelity response. In either case, great care must be taken in the design and manufacture ;~
thereof so that the frequency response of the combination provides a continuous transition between high and low frequency ranges, or else certain frequencies will be attenuated, or peaked, resulting in an undesirable frequency response.
The present day speakers use a magnetic structure that is cup-shaped, with an inner pole piece extending through the center of the opening. The open edge of the cup forms one magnetic poLe, while the free end of the inner pole piece forms the other magnetic pole. The air gap between the pole pieces is reduced to increase the concentration of magnetic flux. In order to achieve greater magnetic flux density and higher power output in the high-frequency range, the permanent magnets used in the magnetic assembly of the prior art are increased in size so that the speakers are very often rated in "pounds" of magnet (i. e., two pound magnet speaker, etc. ).
This increased size and weight add further structural requirements to the speaker housing so that the speaker will not warp. These requirements add to the cost of the speaker. In addition, there is a point of diminishing returns wherein added incremental sizes of ... , , . , ., ,. . . ~ .
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magnets will produce diminishing amounts of additional power output at the high-frequency range. Furthermore, since it is the strength of the magnetic flux density through the armature that determines the efficiency and the output of the speaker, the size of the magnet (in pounds) may be misleading in cases where poor magnetic flux coupling is provided as a result of poor design.
In order to reduce the size and weight of the magnetic structure of speakers, various peripherally-driven transducers ;
were designed, such as, for example, those disclosed in the U. S.
10 Patents Nos. 2, 520, 646 and 2, 535, 757, issued on August 29, 1950, `
and December 26, 1950, respectively, to E. E. Moth and J. J. ~` 9 Root, respectively. These transducers include armature plates secured to the periphery of the diaphragm and a combined perma-nent magnettand electromagnetic stator arrangement to impart varying magnetic flux to the armature. Such an arrangement pro-vides sufficient power and fidelity for telephone purposes as set forth in U. S. Patent No. 2, 520, 646. The arrangement disclosed in U. S. Patent No. 2, 537, 757 may have provided sufficient fidelity over twenty years ago, but would probably be considered poor in 20 today's standards. The limited fidelity results from the inherent disadvantages in driving a speaker by modulating the magnetic flux of the stator through the use of a stator coil. The coil required to provide the necessary flux variation introduces a large reactive impedance in the circuit that Limits its overaLl frequency response.
It was found that greater efficiency and higher frequency responses :
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Peripherally-driven electroacoustic transducers have ;
been developed wherein the cup-shaped magnetic speaker structure of the prior art is used along with a coiL attached to the peripheral edge of a diaphragm extending into the air gap. Because of the massive magnetic structure invoLved (wherein essentially the entire central portion of the cup-shaped magnet is formed speaker iron), the arrangement, as a practical matter, is limited in size, for use as a microphone, or as a tweeter speaker, Any increase in size to provide a good base frequency response would be prohibitive because of weight and cost.
Electromagnetic transducers are presently being used in control apparatus, such as a pneumatic controller (for converting electrical signals into pressure, or pressure into electrical signals) that employ the same cup-shaped magnetic structure as presently i used in speakers to drive a ringishaped armature. Because of the weight and size of such a magnetic structure, and the lack of avail-able space, the forces, or electrical signals, produced by such transducers are rather limited. As a result, intricate lever ~
mechanisms must be used with such transducers to provide the -desired conversion and hence add to the expense of such apparatus.
It would be highly desirable if a transducer could produce the forces, or electrical signals, needed for such control apparatus without requiring the massive and heavy magnetic structure, particularly 1~6~
so if greater forces or higher amplitude electrical signals couLd be produce(d without requiring additional space, In addition to the foregoing, the electroacoustic trans-ducers of the prior art are highly directional. Most of the acoustic energy generated by the electroacoustic devices is directed in a cone-shaped patterrl fromthe center of the diaphragm. If an omnidirectional speaker arrangement is desired, a large number of speakers are required to be mounted in some sort of directional array so that the combined effect of all the speakers provides the 10 desired affect. Such an arrangement is quite expensive, requiring many speakers.
It is therefore an object of this invention to provide a ~ `
new and improved electromagnetic transducer for converting electrical energy into movement, and/or converting movement -into electrical energy, It is also an object of this invention to provide a new and improved electromagnetic transducer that can function as either a speaker, a microphone, or a control device.
It is still a further object of this invention to provide a 20 new and improved electroacoustic transducer that produces increased power output at the high frequency range.
It is also an object of this invention to provide a new and irnproved electroacoustic transducer that is relatively light weight ~-and can produce a wide range of frequenciesJ including the high, intermediate and low-frequency ranges with a single diaphragm.
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It is another object of the present invention to provide a new and improved electroacoustic transducer that is omnidirectional in its sound propagation.
BRIEF DESCRIPTION OF T'HE INVENTION
Thus the present invention provides an electro-acoustic transducer comprising: a diaphragm; tubular shaped current conduction means secured to said diaphra~m along a peripheral edge thereof; concentric tubular shaped open ended magnetic flux translative elements providing at least one tubular shaped air gap therebetween for receiving said current conduction means; and permanent magnet means mounted between said elements so that said elements concentrate magnetic flux '' from said permanent magnet means through said air gap.
In certain embodiments the transducer of the invention includes an elongated rim-shaped magnetic means having poles of opposite magnetic polarity providing an air ; -gap that has the same general elongated configuration as the magnetis means. Current conduction means, such as, for example, a coil, having the s~me general configuration as ~ ',' the air gap, is positioned to extend within the air gap and is , responsive to the current flow therethrough to produce move-ments, or is responsive to a force applied thereto to generate electrical signals.
In the case of an electroacoustic transducer embodying the invention, the current conduction means is secured to a diaphragm adjacent the peripheral edge thereof -~-so that forces are applied to, or received from, the diaphragm periphery. , ~ ,.
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In accordance with an embodiment of the invention, the magnetic means provides an air gap that has an elongated shape. The air gap can be continuous or discontinuous.
The current conduction means has the same elongated shape as the air gap and is mounted to extend within the air gap for movements transverse the flow of magnetic flux. The magnetic means, the air gap, and the current conduction means can have any regular tubular shape such as, for example, annular, polygon, etc., or can have a serpentine shape.
In another embodiment the invention provides a -transducer comprising: a pair of tubular shaped magnetic flux translative elements mounted in a substnatially con~
centric arrangement for providing therebetween at least one tubular shaped air gap, one af said pair of elements being ~-open at both ends while the other one of said pair of elements being open at at least one end, and permanent magnetic means mounted between said pair of elements for providing magnetic flux flow through said elements and said air ~ap current conduction means having a shape to fit ~ ~within said air gap, and means for mounting said current ;conduction means so that at least a portion thereof extends within said air gap so that in response to a current flow through said current conduction means said current conduction ~ ~;means moves within said air gap.
In another embodiment the present invention provides an electroacoustic transducer comprising: a first metallic element having an open ended tubular shape; a second metallic element, having substantially the same tubular É
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shape as said first element but having smaller dimensions so that the second element is posit:ioned in a substantially concentric relation with said first element; permanent magnet means mounted between the first and second elements and adjacent one end of each of said elements so that the other end of each of said first and second elements define an air gap therebetween and wherein magnetic flux flows from said permanent magnet means through a path including said elements and said air gap; current conduction means, having substantially the same configuration as said air gap, ~ :;
mounted for movement within said air gap, and diaphragm means, having substantially the same geometric configuration as the area enclosed by said current conduction means, extending across said current conduction means and attached thereto. ~ .
In another embodiment the present invention provides an electroacoustic transducer comprising: a stator including a plurality of tubular shaped open ended magnetic flux translative elements positioned in a substantially concentric relation for providing two separate air gaps that have sub-stantially the same tubular shape as said elements and are located adjacent and parallel to each other with a separation in between, and permanent magnet means mounted between said elements to provide magnetic flux flow through said elements and said air gaps; current conduction means, having sub-stantially the same configuration as said air gaps; means for mounting said current conduction means so that said current conduction means extends within both air gaps for -- 8 ~
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free movement, in response to a current flow therethrough, in a direction transverse the direction of magnetic flux flow through said air gaps, and diaphragm means connected to said current conduction means adjacent the peripheral edge of the diaphragm means enclosing at least the area defined by the shape of the current conduction means and extending through said separation between said air gaps.
In another embodiment the present invention provides an electromagnetic transducer comprising: stator means including first and second tubular shaped open ended ~ :
magnetic flux translative elements, the second element having smaller dimensions than the first element so that the second element is positioned in a substantially con- -centric relation within the second element, first and second : -tubular shaped pole pieces extending from said first and `~ ~!
second elements, respectively, and adjacent one end thereof .~
so that said first and second pole pieces define a tubular ~. .
shaped air gap therebetween,and permanent magnet means mounted between said first and second elements with opposite ; .
poles facing separate ones of first and second elements so that magnetic flux flows from said permanent magnet means through a path including the first and second.:elements and said air gap, the cross-sectional area of the permanent magnet means, transverse the direction of magnetic flux flow, is substantially greater than the crass-sectional area of the air gap, transverse the direction of magnetic ~ :
flux flow, and current conduction means, having substantially .. ::
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the same tubular shape as said air gap, movably mounted in - ~
said air gap. ` .
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Since the magnetic means has a tubular rim-type shape, it provides a light-weight, low-cost, means for providing an elongated air gap having high density magnetic flux flowing therethrough. The combination of the elongated air gap and the current conduction means located thereint provides for an arrangement wherein the diaphragm is driven at its outer extremities ~peripherally), resulting in a sub-stantially larger working area for the generation of high frequencies than with the conventional center-driven diaphragm and thereby greatly increasing the efficiency of the speaker. Furthermore, 10 since the high frequencies are generated along the peripheral edge of the diaphragm, depending upon the diaphragm shape, the speaker can provide an on~nidirectional high-frequency pattern of sound - `
propagation, The electromagnetic transd~lcer can be built with two units back-to-back for use as a stereo speaker. In addition to the fore- -going, the diaphragm can be made of clear plastic, or glass, to provide a transparent center portion. ~ `
The electromagnetic transducer can also include two parallel air gaps adjacent each other with the cùrrent conduction 20 means (arrnature) extending Lnto both air gaps for providing further magnetic flux for driving the armature.
Alternately, the electromagnetic transducer can include two air gaps located in tandem with separate current conduction ~
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means located in each air gap. With such an arrangement, such current conductions means (armature) can drive separate elements, or can be interconnected in tandem to drive a single element.
BP~IEF DESCRIPTION OF THE: DRAV~rlNGS
. . _ Figure 1 is a perspective view of an embodiment of an -electromagnetic transducer, including the invention, having a ~ ~, round or disc-shaped configuration;
Figure 2 is a front view of the electromagnetic trans-ducer of Figure 1 with the diaphragm removed;
Figure 3 is a side view of the diaphragm of t~,f~ec'~ro-magnetic tra~s~oer;~ioiFigure 1;
Figure 4 is a front view of the diaphragm of Figure 3;
Figure 5 is a side view of the electromagnetic transducer ~ ;
of Figure 1;
Figure 6 Is a sectional view of the electromagnetic trans- ~;
ducer of Figure 1 taken along the lines 6-6;
Figure 7 is a sectional view of the air gap portion of the electromagnetic transducer of Figure 1 including a pair of "()^7' rings for maintaining the diaphragm within the air gap; :
Figure 8 is a sectional view of a portion of the electro-magnetic transducer of Figure 1 taken along the lines 8-8 and using a flexible ring for maintaining the diaphragm within the air 20 gap;
Figure 9 is a sectional view of the electromagnetic transducer of Figure 1 taken along lines 9-9 of Figure 5;
Figure 10 is a sectional view of the electromagnetic ~-.. - -transducer of Figure 1 taken along lines 10-10 of Figure 5, with the diaphragm removed;
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Figure 11 is an enlarged view of a portion of the diaphragm of the electromagnetic transducer of Figure 1 taken along Lines 11-11 of Figure 3; ~
Figure 12 is a perspective vi.ew of a second embodiment of an electromagnetic transducer, including the ir~vention, having a generally rectangular shape;
Figure 13 is a perspective view of a third embodiment of an electromagnetic transducer, including the invention, having a generally triangular shape;
Figure 14 is a fourth embodiment of an electromagnetic transducer, including the invention, including two transducers back-to-back for stereo operation; ~:
Figure 15 is a sectional view of a fifth embodiment of an electromagnetic transducer, including the invention, wherein the :.
armature extends within two air gaps; : ;
Figure 16 is a front view of the annular-shaped electro-magnetic transducer of Figure 1 with the diaphragm removed and with the air gap separated into sections;
Figure 17 is a side view of a diaphragm for the elecit~o- :
20 magnetic transducer of Figure 16 having segments removed from the edge thereof to fit within the sectorized air gap and having a continuous coil wound around the edge thereof; :
Figure 18 is a modification of the diaphragm of Figure 17 having a plurality of separate coils secured to the peripheral edge of the diaphragm; ~ :
--~2--Figure 19 is a sectional view of a sixth embodiment of an electromagnetic transducer, including the invention, having two armatures that can function as a control device;
Figure 20 is a side ~riew oE the electromagnetic trans-ducer of Figure 19; and ~ !
Figure 21 is a plane view of a magnetic structure for an electromagnetic transducer, including the invention, wherein the air gap has a "U" shaped serpentine configuration.
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DETAILED DESCRIPTION OF THE INVENTION
An electromagnetic transducer including the invention has a magnetic structure with an ~longat~dl continuous or discontinuous air gap. The magnetic structure defines a closed curve (i. e., ~; ' outlines a closed geometric configuration) and has a hollow rim- ~;
type shape, such as the annular or tubular shape of a ring, or the straight-sided tukular shape of an outline of a polygon, such as a -rectangle, a triangle, or a serpentine configuration. The air gap has the same general shape as the magnetic structure. ~ , The electromagnetic transducers of Figures 1-18 are described in the context of electroacoustic transducers for con-verting electrical signals into sounds ~speakers) and/or for converting sounds into electrical energy (microphones). In all such cases, the armature is connected to the periphery of a dia~
phragm to apply forces thereto, or to receive forces therefrom.
With a diaphragm as an input or output device, the magnetic ar na~
structure takes on a regular tubular hollow form (annular, poLygon, ~t;3'7~
etc. ) to apply or receive forces Erom the periphery of the diaphragm, However, it is to be un derstood that the electromagnetic transducer of Figures 1 - 18 also can function as a force transducer for use in a variety of controL apparatus, wherein the diaphragm is removed and some sort of coupling device, such as, for example, a lever system, is secured to the armature to provide îor the transLation of the armature movement. The Figures 19 - 21 are described in the context of specialized control system transducers wherein dia- ;
phragms are not required and the magnetic structure and air gap 10 can take more the complex serpentine tubular forms. By tubular shaped we mean any rim-type shape structure wherein an empty or hollow space is encompassed or surrounded by the rim-shaped -structure.
The embodiment of the electroacoustic transducer illus-trated in Figures 1 - 11 includes an annular or tubular-shaped housing 10, having a magnetic structure that provides a tubular ring-shaped air gap 120 The air gap 12 provides the magnetic flux for producing the transducer action~ A diaphragm 14, having the ~ ;
general form of the geometric configuration enclosed by the air 20 gap 12, is mounted with the peripheral edge 30 thereof extending within the air gap 12. The diaphragm 14 has the general form of a disk, with a slight convex shape, and with the peripheral edge 30 ;
thereof folded over to extend transverse (generally normal) to the plane of the diaphragm 14 and into the air gap 12. The edge 30 of the diaphragm 14 follows the same general ring shape as that of ~` "
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the air gap 12. Current conduction means, such as a coil 18, is attached to the diaphragm 14 adjacent to the peripheral edge 30 ~as illustrated in Figures 3 and 4) so that when the edge 30 of the diaphragm 14 is positioned in the air gap 12, the current conduc-tion means also extends within the air gapO The current conduction means or coil 16 i9 wound in the form of a ring, the same general tubular shape configuration as the air gap 12.
The housing 10 of the electroacoustic transducer is :`
formed with an inner metallic annular-shaped element or ring 18, 10 and an outer annular shaped element or ring 20. Magnetic means 22 is mounted between the inner and outer rings 18 and 2û, with the opposite poles thereof positioned adjacent to the inner and ~ :~
outer rings 18 and 20 as illustrated in Figures 6, 8, and 9. The .
magnetic means 22 can be a solid continuous or ring-type ceramic, or rare earth magnet, or can comprise a plurality of ceramic magnets mounted adjacent to each other as (illustrated in Fig. 9) to provide the overall affect of a continu,ous annular-shaped magnet. `;. :.
The width of the magnets 22, as viewed in :Figures 6 and 8 is less than the width of the rings 18 and 20. The magnets 22 are mounted ... . . . .
20 adjacent an end of the rings 18 and 20, opposite the end that extends toward the diaphragm 14. A pair of annular or ring-shaped pole ~
pieces 24 and 26 are mounted adjacent the end of the inner and outer ~ ~ :
rings 18 and 20, opposite the end adjacent the magnets 22. The air .. ;~ .
space between the pole pieces 24 and 26 defines the annular or ring-shaped air gap 12 through which magnetic flux flows. Since the two --15-- :
6;~7~3 rings 1~ and 20 cover the entire ends of the magnets 22, substantiaLly all of the magnetic flux from the magnets flows through the easy fLux path (the path of low impedance) which extencls from the magnets through a ring, through a pole piece, through the air gap, through the other pole piece, and back through the other ring to the magnetæ.
The effect of the two r.ings~8 and 20 and the two pole pieces 24 and 26 is to concentrate substantially all of the magnetic flux from the magnets 22 across the air gap 12, The magnetic flux radiating from the large cross-sectional area of the magnets 22 is concen-trated into a much smaller cross-sectional area of the air gap 12 `
thereby providing an extremely concentrated magnetic flux in the air gap.
As illustrated in Figures 3, 4, and 11, the current con-duction means, or coil 16, is wound around the peripheral edge 30 of the diaphragm 14 in a direction parallel to the edge, The coil 16 is fastened by cement to the diaphragm 14 adjacent the edge 30.
As previously mentioned, the folded end 30 of the diaphragm 14 and the coil 16 have substantially the same annular-shaped configuration as the air gap 12, so that the diaphragm end 30, and the coil 16 20 mounted thereon, are inserted into the air gap 12, The coil 16 and the end 30 of the diaphragm 14 are loosely mounted in the air gap 12 for free movement back and forth in a direction transverse the flow of magnetic flux, as illustrated by the arrows 36.
The diaphragm 14 and the coil 16 can be held in place in the air gap 12 by the use of a flexible rubber cem~nt. Alternatively, --~.6--~ .
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the coil 16 and the diaphragm 14 can be held in place by a pair of "O" rings 34 as illustrated in Figure 7. The "O" rings 34 have a cross-sectional diameter in the order of one-ilalE the diameter of the air gap 12 and extend around the entire length thereof. The "O" rings 34 have a thickness so that when the coil 16 and the clia-phragm end are placed thereon, a loose fit is accomplished so that the coil 16 and the diaphragm 14 are free to move back and forth transverse the magnetic field. Another method of maintaining the coil16 and the end of the diaphr agm 14 within the air gap 12 is illustrated in Figure 8. A plastic ring 35 is attached to the outer annular member 20 to extend beyond the end thereof. A very thin nylon cloth ring 33 is attached at one end to the plastic ring 35 and at the other end to the diaphragm 14.
In response to a force applie d to the diaphragm 14, an ~ ~
electrical signal is generated across the coil leads 3B wherein the - ~ ~ -electroacoustic transducer functions as a pickup device, such as a microphoneO Alternatively, in response to a current flow through the coil 16, the diaphragm 14 is forced to move along the direction of the arrows 36 to function as a receiver, or as a speaker. The movement of a coil within a magnetic flux as a result of a physical force applied thereto for producing electricity, or the movement of a coil with a magnetic flux in response to a current flow there~
through for producing sound, are well-known phenomena and do not require any further explanation. Hence, as can be seen in the electromagnetic transducer of the invention, the electromotive ~ `
~:, force is applied along the peripheral edge of the diaphragm 14 thereby providing a large working area for the transLation of forces to and from the diaphragm 14, It should be understood that the electromagnetic trans~
ducer of the invention can have any type of overall configuration.
For example, the air gap 12 can have the tubular form of a polygon .
rather than the ring shape, such as the rectangular tubular conflg-uration illustrated in Figure 12, or the triangular tubuLar ~`~
configuration illustrated in Figure 13, For the purposes of simpli- ~ -fying the explanation of the electromagnetic transducers of .
Figures 12 and 13, the same elements in Figures 12 and 13 as in ~ ~ -Figures 1 - 11 are designated by the same reference numerals, aLthough the configuration or shape of the elements differ. As : . -illustrated in Figures 12 and 13, the inner and outer metallic elements, and the magnetic means mounted therebetween (not shown), ~ ~ -define an air gap 12 having the tubular configuration of the outline of a polygon (such as the rectangle of Figure 12 or the triangle of .l . :
Figure 13). In each of the embodiments of Figures 12 and 13, the peripheral edge of the diaphragm 14 is bent to form an angle trans- ~ :
verse to the plane of the diaphragm 14 and has the same general ~
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shape or configuration as the air gap 12 (rectangle, triangle, etc~
In addition, the current conduction means or coil 16 (not shown) is attached adjacent to the peripheral edge of the diaphragm 14 and extends within the air gap 12 (In a manner as previously discussed with regard to Figures 1 - 11). As in the case of the transducer of -18~
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Figures 1 - 11, the diaphragm 14 of Figures 12 and 13, and the current conduction means attached thereto, are free to move back -and forth within the air gap 12 in a direction transverse to the flow of magnetic flux, in the same manner as discussed above, and therefore is free to function as either a microphone or as a speaker. ;
Figure 14 illustrates two electromagnetic transducers ' of the type illustrated in Figures 1 - 11 positioned back-to-back to ~
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provide a double speaker configuration for producing a stereo 10 effect. When the two electromagnetic transducers 10A and 10B
are mounted adjacent to each other as illustrated in Figure 12, a partition 44 is positioned between the two transducers (along the -side opposite that having the diaphragms 14A and 14B) to prevent the interPerence of sound wave therebetween. If a more prominent stereo effect is desired, the transducers 10A and 10B can be separated from each other depending upon the distance between the listener and the transducers. ~
The air gap 12 of Figures 1 - 15 is illustrated as having ;
the shape of a continuous closed curve. If, for some reason, the 20 continuous air gap is not desired, such as, for example, because of the use of very thin rings 18 and 20 for cost reduction or weight `
reduction purposes, the air gap 12 can be broken into a plurality of sectors by the non-metallic (plastic) separators 40 to strengthen the structure (as illustrated in Figure 16). In this case, the dia-phragm 14 is fitted with grooves or slots 42, one for each of the '.J~'; . ;, :: , - . ..... :
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separators 40 (Figure 17) so that the peripheral edge of the diaphragm 14 has the same configuration as the air gap and fits within the air gap. The coil 16 is wound around the p~eripheral edge 30 with portions thereof bent to bypass the slots 42. It should be understood that the size of the separators 40 can be increased in si~e substantially over that illustrated in Figure 16 to provide a plurality of separat~rair gaps and the electromagnetic transducer will still function, but less effectively.
If, for some reason, a plurality of coils are desirable 10 instead of a single coil, a pLurality of coils 16A, 16~, etc., (Fig. 18) can be located along the peripheral edge 30 in an arrangement so that when the diaphragm 14 is located ~ithin the air gap 12 only one-half the coils 16A and 16B (separated by the dashed line 46) extend within the air gap. ~ -In the emb odiment of the electromagnetic transducer of the invention of Figure 15, rather than having the air gap extending outward as illustrated in Figures 1-14 and 16-2OJ the transducer of Figure 15 includes two air gaps 50 and 52, both extending inward. :
The air gap 50 is part of the magnetic flux path for the annular-20 shaped magnet 60, the metallic ring 56, and the annular pole piece 58. The air gap 52 is part of the magnetic flux path for the magnet 62, the ring 56, and the pole piece 64. The pole pieces 58 and 64 are bent inward at the free ends to extend toward the ring 56 to reduce the size of the air gaps 50 and 52. A flat planar disk-shaped diaphragm 58 is fastened along its peripheral edge to an insulating ' `3t~1~3 ring 70. The insulating ring 70 is fastened to the metallic ring 56 by a thin nylon cloth ring 72. A coil 74 is wound around the insu-lating ring 70 in a manner so that the coil 74 extends into both of the air gaps 50 and 52. The direction of the magnetic flux through the air gaps 50 and 52 is of a polarity, and the coil 74 is wound 90 that the current flow in the coil produces an additive force in the air gaps 50 and 52 to move the coil and the diaphragm 14 in the direction of the arrows 76. Although the transducer of ~igure 15 is described as being annular or ring-shaped, it is to be under-stood that the transducer can have any tubular-type form, such as ;
polygon shapes (triangular, rectangularJ etc. ).
The tubu3lar-shapedJ hollow~ magnetic structure pro- ~ -viding an elongated air gap 12 (in the form of a closed curve, or in sections of a closed curve) in combination with the diaphragm 14 ; --(having the edge thereof of the same stlape as the air gap 12) including a coil along its peripheral edge (formed to fit within che air gap 12) provides an arrangement wherein electromotive forces are transmitted between the pole pieces 24 and 26 and the diaphragm 14 over the entire, or portions of, t~Ze peripheral edge of the 20 diaphragm. The combination of the peripheral edge of the diaphragm and the coil attached thereto provides a large working area, wherein the entire~ or a large part of the peripheral edge 30 is exposed to the electromotive forces. This provides a highly-efficient arrangement, particularly at the high-frequency range. In the case wherein the transducer of the invention functions as a speaker, the high-frequency .. -, ~;:
.~ -21-, - . ~ , . . , . :- , -~U~ 7~
signals are generated along the entire circumference or peripheral edge of the diaphragm 14, thereby providing a substantially greater transducing area for the generation of high frequencies. As a result, the single diaphragm 14, in an electroacoustic transducer including the invention, provides a wide r ange of frequencies wherein ~ . .
the effectîve power output at the high-frequency range approaches ~ ~
that of the lower-frequency ranges. There is no need for "tweeter" ;~ ;;
speakers to accentuate the high frequencies~ The entire broad range of audio frequencies are generated by the single diaphragm 14. ~
In addition to the foregoing, it should be noted that since the high `
frequencies are generated at the circurmference or peripheral edge 30 of the diaphragm 14, the propagation of the high-frequency signals - -,, . - .
appears to be in all directions, essentially providing the effect of an omnidirectional speaker. This is because the direction of music and -sound is primarily detected by the human ear from the propagation of the high-frequency sounds. The propagation pattern of the high ;
frequencies from the electroacoustic transducer including the ~ `
invention approaches a pattern of 360 and therefore it is very diffi~
cult for the listener to detect the source of the sound.
In addition to the foregoing, the diaphragm 14 of the electroacoustic transducer including the invention can be made of a variety of thin, fairly-rigid materials, such as, for example, clear ~, ~
plastic or glass. VVith a clear plastic or glass diaphragm, the electroacoustic transducer appears as a hollow ring, or polygon~
shaped tube, with a clear "see-through" center. Eence, various , ~,, --2~
- , .
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i3-7~3 novelty items can be included within the speaker, such as, for example, lighting or color effects wherein the intensity of, and a - ~ -frequency of, illumination and color thereof i9 a function of the `~
amplitude and frequency of the sound being produced (psychedelic effects). Furthermore, the embodiment of the transducer of Figure 12 has the added advantage wherein the rectangular -diaphragm 14 and the elements forming the air gap 12 can be built about the front of a television tube with the clear diaphragm ~;
14 positioned across the face television tube. Such an arrange-10 ment provides a "see-through" speaker for viewing the television screen wherein the diaphragm functions as the source of sound ~-and a very large speaker, having extremely excellent acoustical fidelity, for television sets requiring very little extra space. ;
The embodiment of electromagnetic transducer illustrated in Figures 19 and 20 is described in the context of a transducer for use in control systems, such as, for example, lens focusing, or a pneumatic controller. The transducer includes an annular, tubular~
shaped magnet 100 (of the type specified above) providing the magnetic ;
flux for the transducer. The magnet 100 is secured between an outer ; ~
metallic sleeve 102 and an inner metallic sleeve 104, both of which ~ -extend beyond opposite ends of the magnet 100, The outer sleeve 102 includes the bends 106 and 108 so that the portions3~$~hhes~1eeee~102 and 104 that extend beyond the magnet 100 are brought in close proximity to define two annular, tubular-shaped air gaps 110 and 112. The dimensions of the air gaps 110 and 112 extending along the ~ 637~
direction of the axis 114 of the transducer and are substantially longer than the corresponding dimensions of the transducer of Figures 1 - 18 since it is movement, rather than sound, to be the input or output signal.
Separate current conduction means ~armatures 116 and 118) are positioned in separate ones of the air gaps and are mounted on the rings 120 and 122. The rings 120 and 122 include a plurality of tabs 124 which extend into the guideways 126 to pro-vide bearing surfaces for the armatures. The item to be controlled 10 is secured to the rings 120 and 122, For example, the coils 116 and 118 can be driven by a differential amplifier to provide a cor-responding differential movement from the coils. Alternatively, -the coils 116 and 118 can be driven in parallel and the coils con-nected to a lever mechanism in an aiding tandem management.
If the transducer is to beused in an optical system, the lens or -~
lenses can be secured to the rings 120 and 122. The armatures ~;
can be coupled to drive a single lens or can drive separate lenses.
In addition, similar transducers of the type illustrated in Figures 18 and 20 can be stacked in a tandem arrangement, so that the trans- ;
2G ducer can provide a variety of functions in response to a large com-bination of input signals. ; ~Ç
Although the transducer of Figures 19 and 20 is illustrated as having an annular tubular shape, it is to be understood that it can ; ~ -have a variety of tubular shapes, such as triangular, rectangular, oval, etc., depending upon the specific design requirements.
.... ... .
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At times, the space provided for a control transducer may be limited and weight may be a problern, The air gap of the trans- ;
ducer of the invention can be increased by providing a serpentine type of configuration, such as the "U" shaped configuration of Figure 21 wherein the elongated length of the air gap is increased over that provided by the regular tubular-shaped configurations of Figures 1 - 20. As illustrated in Figure 21, the transducer includes an inner "U" shaped metallic element 130 and an outer "U" shaped metallic element 132 having a "U" shaped magnet structure (not shown) disposed therebetweenO A pair of "U" shaped ~ - ~
pole pieces 134 and 136 extend toward each other from the elements ~ 7 130 and 132 to define a continuous "U" shaped air gap 138 defining a closed curve. The armature for the transducer of Figure 21 will also have a "U" shape to conform with the air gap 138. As can be seen, since the length of the air gap 138 is greater than that pro~
vided by a tubular configuration of that of Figures 1 - 20, a greater working area is provided and, therefore, a greater output verses space is achieved by this arrangement. It should be understood with the transducer of the invention that any type of serpentine ;-closed curve air gap configuration can l~e provided, depending upon the design reqoirer.~erlts and the :pace avaiiable.
. ~, .
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This invention pertains in general to electromagnetic ~ :
transducers, and, more particularly, to transducers for converting electrical energy into movements or sounds, and/or movements or sounds into electrical energy.
Electromagnetic transducers for converting movements or forces (such as sound) into electrical energy, or for converting electrical energy into movements or forces (such as sound), include an electrically-conductive movable element (armature) and a sta-tionary magnetic element (stator) for applying magnetic flux thereto. -Forces applied to the armature, as a result of magnetic flux vari-ations, convert electrical energy into movements, and in the case of a speaker, soundO Alternately, physical forces on the armature ~ ;
(such as in the case of microphones) oreate changes in the magnetic flux and generate electrical signals due to the movement of the ` -. ,~ . -~ . .
armature. ` -In the prior art speakers, the armature is located in a ; ~ `
magnetic field and is generally secured near the center of the diaphragm (speaker cone). The armature usually includes a coil that ,;,: ~
receives the electrical signals to be converted into soundu The high frequencies are generated on the center of the diaphragm while the intermediate and base frequencies are generated over the entire `~
,, surface of the coneO Such an arrangement has poor efficiency at ~ -high frequencies and, as a result, usually has a degraded high fre~
quency response.
~6~
. . .
In order to obtain an improved high-frequency re~ponse, a small "tweeter" type speaker cone has been mounted within the center of the large speaker cone to get greater power output at high frequencies. Other arrangements include separate base and tweeter speakerss electrically interconnected with cross-over networks to provide an overall high-fidelity response. In either case, great care must be taken in the design and manufacture ;~
thereof so that the frequency response of the combination provides a continuous transition between high and low frequency ranges, or else certain frequencies will be attenuated, or peaked, resulting in an undesirable frequency response.
The present day speakers use a magnetic structure that is cup-shaped, with an inner pole piece extending through the center of the opening. The open edge of the cup forms one magnetic poLe, while the free end of the inner pole piece forms the other magnetic pole. The air gap between the pole pieces is reduced to increase the concentration of magnetic flux. In order to achieve greater magnetic flux density and higher power output in the high-frequency range, the permanent magnets used in the magnetic assembly of the prior art are increased in size so that the speakers are very often rated in "pounds" of magnet (i. e., two pound magnet speaker, etc. ).
This increased size and weight add further structural requirements to the speaker housing so that the speaker will not warp. These requirements add to the cost of the speaker. In addition, there is a point of diminishing returns wherein added incremental sizes of ... , , . , ., ,. . . ~ .
~63~
magnets will produce diminishing amounts of additional power output at the high-frequency range. Furthermore, since it is the strength of the magnetic flux density through the armature that determines the efficiency and the output of the speaker, the size of the magnet (in pounds) may be misleading in cases where poor magnetic flux coupling is provided as a result of poor design.
In order to reduce the size and weight of the magnetic structure of speakers, various peripherally-driven transducers ;
were designed, such as, for example, those disclosed in the U. S.
10 Patents Nos. 2, 520, 646 and 2, 535, 757, issued on August 29, 1950, `
and December 26, 1950, respectively, to E. E. Moth and J. J. ~` 9 Root, respectively. These transducers include armature plates secured to the periphery of the diaphragm and a combined perma-nent magnettand electromagnetic stator arrangement to impart varying magnetic flux to the armature. Such an arrangement pro-vides sufficient power and fidelity for telephone purposes as set forth in U. S. Patent No. 2, 520, 646. The arrangement disclosed in U. S. Patent No. 2, 537, 757 may have provided sufficient fidelity over twenty years ago, but would probably be considered poor in 20 today's standards. The limited fidelity results from the inherent disadvantages in driving a speaker by modulating the magnetic flux of the stator through the use of a stator coil. The coil required to provide the necessary flux variation introduces a large reactive impedance in the circuit that Limits its overaLl frequency response.
It was found that greater efficiency and higher frequency responses :
B~
. . .
~37~3 would be achieved with the coil mounted on the movable armature as in most present day speakers.
Peripherally-driven electroacoustic transducers have ;
been developed wherein the cup-shaped magnetic speaker structure of the prior art is used along with a coiL attached to the peripheral edge of a diaphragm extending into the air gap. Because of the massive magnetic structure invoLved (wherein essentially the entire central portion of the cup-shaped magnet is formed speaker iron), the arrangement, as a practical matter, is limited in size, for use as a microphone, or as a tweeter speaker, Any increase in size to provide a good base frequency response would be prohibitive because of weight and cost.
Electromagnetic transducers are presently being used in control apparatus, such as a pneumatic controller (for converting electrical signals into pressure, or pressure into electrical signals) that employ the same cup-shaped magnetic structure as presently i used in speakers to drive a ringishaped armature. Because of the weight and size of such a magnetic structure, and the lack of avail-able space, the forces, or electrical signals, produced by such transducers are rather limited. As a result, intricate lever ~
mechanisms must be used with such transducers to provide the -desired conversion and hence add to the expense of such apparatus.
It would be highly desirable if a transducer could produce the forces, or electrical signals, needed for such control apparatus without requiring the massive and heavy magnetic structure, particularly 1~6~
so if greater forces or higher amplitude electrical signals couLd be produce(d without requiring additional space, In addition to the foregoing, the electroacoustic trans-ducers of the prior art are highly directional. Most of the acoustic energy generated by the electroacoustic devices is directed in a cone-shaped patterrl fromthe center of the diaphragm. If an omnidirectional speaker arrangement is desired, a large number of speakers are required to be mounted in some sort of directional array so that the combined effect of all the speakers provides the 10 desired affect. Such an arrangement is quite expensive, requiring many speakers.
It is therefore an object of this invention to provide a ~ `
new and improved electromagnetic transducer for converting electrical energy into movement, and/or converting movement -into electrical energy, It is also an object of this invention to provide a new and improved electromagnetic transducer that can function as either a speaker, a microphone, or a control device.
It is still a further object of this invention to provide a 20 new and improved electroacoustic transducer that produces increased power output at the high frequency range.
It is also an object of this invention to provide a new and irnproved electroacoustic transducer that is relatively light weight ~-and can produce a wide range of frequenciesJ including the high, intermediate and low-frequency ranges with a single diaphragm.
;~;' '~', .
~4 ~
-~363~
It is another object of the present invention to provide a new and improved electroacoustic transducer that is omnidirectional in its sound propagation.
BRIEF DESCRIPTION OF T'HE INVENTION
Thus the present invention provides an electro-acoustic transducer comprising: a diaphragm; tubular shaped current conduction means secured to said diaphra~m along a peripheral edge thereof; concentric tubular shaped open ended magnetic flux translative elements providing at least one tubular shaped air gap therebetween for receiving said current conduction means; and permanent magnet means mounted between said elements so that said elements concentrate magnetic flux '' from said permanent magnet means through said air gap.
In certain embodiments the transducer of the invention includes an elongated rim-shaped magnetic means having poles of opposite magnetic polarity providing an air ; -gap that has the same general elongated configuration as the magnetis means. Current conduction means, such as, for example, a coil, having the s~me general configuration as ~ ',' the air gap, is positioned to extend within the air gap and is , responsive to the current flow therethrough to produce move-ments, or is responsive to a force applied thereto to generate electrical signals.
In the case of an electroacoustic transducer embodying the invention, the current conduction means is secured to a diaphragm adjacent the peripheral edge thereof -~-so that forces are applied to, or received from, the diaphragm periphery. , ~ ,.
l~V63~
In accordance with an embodiment of the invention, the magnetic means provides an air gap that has an elongated shape. The air gap can be continuous or discontinuous.
The current conduction means has the same elongated shape as the air gap and is mounted to extend within the air gap for movements transverse the flow of magnetic flux. The magnetic means, the air gap, and the current conduction means can have any regular tubular shape such as, for example, annular, polygon, etc., or can have a serpentine shape.
In another embodiment the invention provides a -transducer comprising: a pair of tubular shaped magnetic flux translative elements mounted in a substnatially con~
centric arrangement for providing therebetween at least one tubular shaped air gap, one af said pair of elements being ~-open at both ends while the other one of said pair of elements being open at at least one end, and permanent magnetic means mounted between said pair of elements for providing magnetic flux flow through said elements and said air ~ap current conduction means having a shape to fit ~ ~within said air gap, and means for mounting said current ;conduction means so that at least a portion thereof extends within said air gap so that in response to a current flow through said current conduction means said current conduction ~ ~;means moves within said air gap.
In another embodiment the present invention provides an electroacoustic transducer comprising: a first metallic element having an open ended tubular shape; a second metallic element, having substantially the same tubular É
;' ~ t7~
shape as said first element but having smaller dimensions so that the second element is posit:ioned in a substantially concentric relation with said first element; permanent magnet means mounted between the first and second elements and adjacent one end of each of said elements so that the other end of each of said first and second elements define an air gap therebetween and wherein magnetic flux flows from said permanent magnet means through a path including said elements and said air gap; current conduction means, having substantially the same configuration as said air gap, ~ :;
mounted for movement within said air gap, and diaphragm means, having substantially the same geometric configuration as the area enclosed by said current conduction means, extending across said current conduction means and attached thereto. ~ .
In another embodiment the present invention provides an electroacoustic transducer comprising: a stator including a plurality of tubular shaped open ended magnetic flux translative elements positioned in a substantially concentric relation for providing two separate air gaps that have sub-stantially the same tubular shape as said elements and are located adjacent and parallel to each other with a separation in between, and permanent magnet means mounted between said elements to provide magnetic flux flow through said elements and said air gaps; current conduction means, having sub-stantially the same configuration as said air gaps; means for mounting said current conduction means so that said current conduction means extends within both air gaps for -- 8 ~
~ .
.~1.0~i3'7~
free movement, in response to a current flow therethrough, in a direction transverse the direction of magnetic flux flow through said air gaps, and diaphragm means connected to said current conduction means adjacent the peripheral edge of the diaphragm means enclosing at least the area defined by the shape of the current conduction means and extending through said separation between said air gaps.
In another embodiment the present invention provides an electromagnetic transducer comprising: stator means including first and second tubular shaped open ended ~ :
magnetic flux translative elements, the second element having smaller dimensions than the first element so that the second element is positioned in a substantially con- -centric relation within the second element, first and second : -tubular shaped pole pieces extending from said first and `~ ~!
second elements, respectively, and adjacent one end thereof .~
so that said first and second pole pieces define a tubular ~. .
shaped air gap therebetween,and permanent magnet means mounted between said first and second elements with opposite ; .
poles facing separate ones of first and second elements so that magnetic flux flows from said permanent magnet means through a path including the first and second.:elements and said air gap, the cross-sectional area of the permanent magnet means, transverse the direction of magnetic flux flow, is substantially greater than the crass-sectional area of the air gap, transverse the direction of magnetic ~ :
flux flow, and current conduction means, having substantially .. ::
. .
the same tubular shape as said air gap, movably mounted in - ~
said air gap. ` .
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Since the magnetic means has a tubular rim-type shape, it provides a light-weight, low-cost, means for providing an elongated air gap having high density magnetic flux flowing therethrough. The combination of the elongated air gap and the current conduction means located thereint provides for an arrangement wherein the diaphragm is driven at its outer extremities ~peripherally), resulting in a sub-stantially larger working area for the generation of high frequencies than with the conventional center-driven diaphragm and thereby greatly increasing the efficiency of the speaker. Furthermore, 10 since the high frequencies are generated along the peripheral edge of the diaphragm, depending upon the diaphragm shape, the speaker can provide an on~nidirectional high-frequency pattern of sound - `
propagation, The electromagnetic transd~lcer can be built with two units back-to-back for use as a stereo speaker. In addition to the fore- -going, the diaphragm can be made of clear plastic, or glass, to provide a transparent center portion. ~ `
The electromagnetic transducer can also include two parallel air gaps adjacent each other with the cùrrent conduction 20 means (arrnature) extending Lnto both air gaps for providing further magnetic flux for driving the armature.
Alternately, the electromagnetic transducer can include two air gaps located in tandem with separate current conduction ~
~ .' ~, ., '.
means located in each air gap. With such an arrangement, such current conductions means (armature) can drive separate elements, or can be interconnected in tandem to drive a single element.
BP~IEF DESCRIPTION OF THE: DRAV~rlNGS
. . _ Figure 1 is a perspective view of an embodiment of an -electromagnetic transducer, including the invention, having a ~ ~, round or disc-shaped configuration;
Figure 2 is a front view of the electromagnetic trans-ducer of Figure 1 with the diaphragm removed;
Figure 3 is a side view of the diaphragm of t~,f~ec'~ro-magnetic tra~s~oer;~ioiFigure 1;
Figure 4 is a front view of the diaphragm of Figure 3;
Figure 5 is a side view of the electromagnetic transducer ~ ;
of Figure 1;
Figure 6 Is a sectional view of the electromagnetic trans- ~;
ducer of Figure 1 taken along the lines 6-6;
Figure 7 is a sectional view of the air gap portion of the electromagnetic transducer of Figure 1 including a pair of "()^7' rings for maintaining the diaphragm within the air gap; :
Figure 8 is a sectional view of a portion of the electro-magnetic transducer of Figure 1 taken along the lines 8-8 and using a flexible ring for maintaining the diaphragm within the air 20 gap;
Figure 9 is a sectional view of the electromagnetic transducer of Figure 1 taken along lines 9-9 of Figure 5;
Figure 10 is a sectional view of the electromagnetic ~-.. - -transducer of Figure 1 taken along lines 10-10 of Figure 5, with the diaphragm removed;
--11-- ~: ,; .: , i. -,- . ':~ : : . ' . . . ' . ' ! .' . ~ .
37~a~
Figure 11 is an enlarged view of a portion of the diaphragm of the electromagnetic transducer of Figure 1 taken along Lines 11-11 of Figure 3; ~
Figure 12 is a perspective vi.ew of a second embodiment of an electromagnetic transducer, including the ir~vention, having a generally rectangular shape;
Figure 13 is a perspective view of a third embodiment of an electromagnetic transducer, including the invention, having a generally triangular shape;
Figure 14 is a fourth embodiment of an electromagnetic transducer, including the invention, including two transducers back-to-back for stereo operation; ~:
Figure 15 is a sectional view of a fifth embodiment of an electromagnetic transducer, including the invention, wherein the :.
armature extends within two air gaps; : ;
Figure 16 is a front view of the annular-shaped electro-magnetic transducer of Figure 1 with the diaphragm removed and with the air gap separated into sections;
Figure 17 is a side view of a diaphragm for the elecit~o- :
20 magnetic transducer of Figure 16 having segments removed from the edge thereof to fit within the sectorized air gap and having a continuous coil wound around the edge thereof; :
Figure 18 is a modification of the diaphragm of Figure 17 having a plurality of separate coils secured to the peripheral edge of the diaphragm; ~ :
--~2--Figure 19 is a sectional view of a sixth embodiment of an electromagnetic transducer, including the invention, having two armatures that can function as a control device;
Figure 20 is a side ~riew oE the electromagnetic trans-ducer of Figure 19; and ~ !
Figure 21 is a plane view of a magnetic structure for an electromagnetic transducer, including the invention, wherein the air gap has a "U" shaped serpentine configuration.
.
DETAILED DESCRIPTION OF THE INVENTION
An electromagnetic transducer including the invention has a magnetic structure with an ~longat~dl continuous or discontinuous air gap. The magnetic structure defines a closed curve (i. e., ~; ' outlines a closed geometric configuration) and has a hollow rim- ~;
type shape, such as the annular or tubular shape of a ring, or the straight-sided tukular shape of an outline of a polygon, such as a -rectangle, a triangle, or a serpentine configuration. The air gap has the same general shape as the magnetic structure. ~ , The electromagnetic transducers of Figures 1-18 are described in the context of electroacoustic transducers for con-verting electrical signals into sounds ~speakers) and/or for converting sounds into electrical energy (microphones). In all such cases, the armature is connected to the periphery of a dia~
phragm to apply forces thereto, or to receive forces therefrom.
With a diaphragm as an input or output device, the magnetic ar na~
structure takes on a regular tubular hollow form (annular, poLygon, ~t;3'7~
etc. ) to apply or receive forces Erom the periphery of the diaphragm, However, it is to be un derstood that the electromagnetic transducer of Figures 1 - 18 also can function as a force transducer for use in a variety of controL apparatus, wherein the diaphragm is removed and some sort of coupling device, such as, for example, a lever system, is secured to the armature to provide îor the transLation of the armature movement. The Figures 19 - 21 are described in the context of specialized control system transducers wherein dia- ;
phragms are not required and the magnetic structure and air gap 10 can take more the complex serpentine tubular forms. By tubular shaped we mean any rim-type shape structure wherein an empty or hollow space is encompassed or surrounded by the rim-shaped -structure.
The embodiment of the electroacoustic transducer illus-trated in Figures 1 - 11 includes an annular or tubular-shaped housing 10, having a magnetic structure that provides a tubular ring-shaped air gap 120 The air gap 12 provides the magnetic flux for producing the transducer action~ A diaphragm 14, having the ~ ;
general form of the geometric configuration enclosed by the air 20 gap 12, is mounted with the peripheral edge 30 thereof extending within the air gap 12. The diaphragm 14 has the general form of a disk, with a slight convex shape, and with the peripheral edge 30 ;
thereof folded over to extend transverse (generally normal) to the plane of the diaphragm 14 and into the air gap 12. The edge 30 of the diaphragm 14 follows the same general ring shape as that of ~` "
"
-14- ; ;
.. . . .
, - . . . . . . .. .
.
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the air gap 12. Current conduction means, such as a coil 18, is attached to the diaphragm 14 adjacent to the peripheral edge 30 ~as illustrated in Figures 3 and 4) so that when the edge 30 of the diaphragm 14 is positioned in the air gap 12, the current conduc-tion means also extends within the air gapO The current conduction means or coil 16 i9 wound in the form of a ring, the same general tubular shape configuration as the air gap 12.
The housing 10 of the electroacoustic transducer is :`
formed with an inner metallic annular-shaped element or ring 18, 10 and an outer annular shaped element or ring 20. Magnetic means 22 is mounted between the inner and outer rings 18 and 2û, with the opposite poles thereof positioned adjacent to the inner and ~ :~
outer rings 18 and 20 as illustrated in Figures 6, 8, and 9. The .
magnetic means 22 can be a solid continuous or ring-type ceramic, or rare earth magnet, or can comprise a plurality of ceramic magnets mounted adjacent to each other as (illustrated in Fig. 9) to provide the overall affect of a continu,ous annular-shaped magnet. `;. :.
The width of the magnets 22, as viewed in :Figures 6 and 8 is less than the width of the rings 18 and 20. The magnets 22 are mounted ... . . . .
20 adjacent an end of the rings 18 and 20, opposite the end that extends toward the diaphragm 14. A pair of annular or ring-shaped pole ~
pieces 24 and 26 are mounted adjacent the end of the inner and outer ~ ~ :
rings 18 and 20, opposite the end adjacent the magnets 22. The air .. ;~ .
space between the pole pieces 24 and 26 defines the annular or ring-shaped air gap 12 through which magnetic flux flows. Since the two --15-- :
6;~7~3 rings 1~ and 20 cover the entire ends of the magnets 22, substantiaLly all of the magnetic flux from the magnets flows through the easy fLux path (the path of low impedance) which extencls from the magnets through a ring, through a pole piece, through the air gap, through the other pole piece, and back through the other ring to the magnetæ.
The effect of the two r.ings~8 and 20 and the two pole pieces 24 and 26 is to concentrate substantially all of the magnetic flux from the magnets 22 across the air gap 12, The magnetic flux radiating from the large cross-sectional area of the magnets 22 is concen-trated into a much smaller cross-sectional area of the air gap 12 `
thereby providing an extremely concentrated magnetic flux in the air gap.
As illustrated in Figures 3, 4, and 11, the current con-duction means, or coil 16, is wound around the peripheral edge 30 of the diaphragm 14 in a direction parallel to the edge, The coil 16 is fastened by cement to the diaphragm 14 adjacent the edge 30.
As previously mentioned, the folded end 30 of the diaphragm 14 and the coil 16 have substantially the same annular-shaped configuration as the air gap 12, so that the diaphragm end 30, and the coil 16 20 mounted thereon, are inserted into the air gap 12, The coil 16 and the end 30 of the diaphragm 14 are loosely mounted in the air gap 12 for free movement back and forth in a direction transverse the flow of magnetic flux, as illustrated by the arrows 36.
The diaphragm 14 and the coil 16 can be held in place in the air gap 12 by the use of a flexible rubber cem~nt. Alternatively, --~.6--~ .
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the coil 16 and the diaphragm 14 can be held in place by a pair of "O" rings 34 as illustrated in Figure 7. The "O" rings 34 have a cross-sectional diameter in the order of one-ilalE the diameter of the air gap 12 and extend around the entire length thereof. The "O" rings 34 have a thickness so that when the coil 16 and the clia-phragm end are placed thereon, a loose fit is accomplished so that the coil 16 and the diaphragm 14 are free to move back and forth transverse the magnetic field. Another method of maintaining the coil16 and the end of the diaphr agm 14 within the air gap 12 is illustrated in Figure 8. A plastic ring 35 is attached to the outer annular member 20 to extend beyond the end thereof. A very thin nylon cloth ring 33 is attached at one end to the plastic ring 35 and at the other end to the diaphragm 14.
In response to a force applie d to the diaphragm 14, an ~ ~
electrical signal is generated across the coil leads 3B wherein the - ~ ~ -electroacoustic transducer functions as a pickup device, such as a microphoneO Alternatively, in response to a current flow through the coil 16, the diaphragm 14 is forced to move along the direction of the arrows 36 to function as a receiver, or as a speaker. The movement of a coil within a magnetic flux as a result of a physical force applied thereto for producing electricity, or the movement of a coil with a magnetic flux in response to a current flow there~
through for producing sound, are well-known phenomena and do not require any further explanation. Hence, as can be seen in the electromagnetic transducer of the invention, the electromotive ~ `
~:, force is applied along the peripheral edge of the diaphragm 14 thereby providing a large working area for the transLation of forces to and from the diaphragm 14, It should be understood that the electromagnetic trans~
ducer of the invention can have any type of overall configuration.
For example, the air gap 12 can have the tubular form of a polygon .
rather than the ring shape, such as the rectangular tubular conflg-uration illustrated in Figure 12, or the triangular tubuLar ~`~
configuration illustrated in Figure 13, For the purposes of simpli- ~ -fying the explanation of the electromagnetic transducers of .
Figures 12 and 13, the same elements in Figures 12 and 13 as in ~ ~ -Figures 1 - 11 are designated by the same reference numerals, aLthough the configuration or shape of the elements differ. As : . -illustrated in Figures 12 and 13, the inner and outer metallic elements, and the magnetic means mounted therebetween (not shown), ~ ~ -define an air gap 12 having the tubular configuration of the outline of a polygon (such as the rectangle of Figure 12 or the triangle of .l . :
Figure 13). In each of the embodiments of Figures 12 and 13, the peripheral edge of the diaphragm 14 is bent to form an angle trans- ~ :
verse to the plane of the diaphragm 14 and has the same general ~
:.-, . .
shape or configuration as the air gap 12 (rectangle, triangle, etc~
In addition, the current conduction means or coil 16 (not shown) is attached adjacent to the peripheral edge of the diaphragm 14 and extends within the air gap 12 (In a manner as previously discussed with regard to Figures 1 - 11). As in the case of the transducer of -18~
3~7~
Figures 1 - 11, the diaphragm 14 of Figures 12 and 13, and the current conduction means attached thereto, are free to move back -and forth within the air gap 12 in a direction transverse to the flow of magnetic flux, in the same manner as discussed above, and therefore is free to function as either a microphone or as a speaker. ;
Figure 14 illustrates two electromagnetic transducers ' of the type illustrated in Figures 1 - 11 positioned back-to-back to ~
~ ;, ~': ,';
provide a double speaker configuration for producing a stereo 10 effect. When the two electromagnetic transducers 10A and 10B
are mounted adjacent to each other as illustrated in Figure 12, a partition 44 is positioned between the two transducers (along the -side opposite that having the diaphragms 14A and 14B) to prevent the interPerence of sound wave therebetween. If a more prominent stereo effect is desired, the transducers 10A and 10B can be separated from each other depending upon the distance between the listener and the transducers. ~
The air gap 12 of Figures 1 - 15 is illustrated as having ;
the shape of a continuous closed curve. If, for some reason, the 20 continuous air gap is not desired, such as, for example, because of the use of very thin rings 18 and 20 for cost reduction or weight `
reduction purposes, the air gap 12 can be broken into a plurality of sectors by the non-metallic (plastic) separators 40 to strengthen the structure (as illustrated in Figure 16). In this case, the dia-phragm 14 is fitted with grooves or slots 42, one for each of the '.J~'; . ;, :: , - . ..... :
.. .: . . .:, . - : :. .
~i3~
separators 40 (Figure 17) so that the peripheral edge of the diaphragm 14 has the same configuration as the air gap and fits within the air gap. The coil 16 is wound around the p~eripheral edge 30 with portions thereof bent to bypass the slots 42. It should be understood that the size of the separators 40 can be increased in si~e substantially over that illustrated in Figure 16 to provide a plurality of separat~rair gaps and the electromagnetic transducer will still function, but less effectively.
If, for some reason, a plurality of coils are desirable 10 instead of a single coil, a pLurality of coils 16A, 16~, etc., (Fig. 18) can be located along the peripheral edge 30 in an arrangement so that when the diaphragm 14 is located ~ithin the air gap 12 only one-half the coils 16A and 16B (separated by the dashed line 46) extend within the air gap. ~ -In the emb odiment of the electromagnetic transducer of the invention of Figure 15, rather than having the air gap extending outward as illustrated in Figures 1-14 and 16-2OJ the transducer of Figure 15 includes two air gaps 50 and 52, both extending inward. :
The air gap 50 is part of the magnetic flux path for the annular-20 shaped magnet 60, the metallic ring 56, and the annular pole piece 58. The air gap 52 is part of the magnetic flux path for the magnet 62, the ring 56, and the pole piece 64. The pole pieces 58 and 64 are bent inward at the free ends to extend toward the ring 56 to reduce the size of the air gaps 50 and 52. A flat planar disk-shaped diaphragm 58 is fastened along its peripheral edge to an insulating ' `3t~1~3 ring 70. The insulating ring 70 is fastened to the metallic ring 56 by a thin nylon cloth ring 72. A coil 74 is wound around the insu-lating ring 70 in a manner so that the coil 74 extends into both of the air gaps 50 and 52. The direction of the magnetic flux through the air gaps 50 and 52 is of a polarity, and the coil 74 is wound 90 that the current flow in the coil produces an additive force in the air gaps 50 and 52 to move the coil and the diaphragm 14 in the direction of the arrows 76. Although the transducer of ~igure 15 is described as being annular or ring-shaped, it is to be under-stood that the transducer can have any tubular-type form, such as ;
polygon shapes (triangular, rectangularJ etc. ).
The tubu3lar-shapedJ hollow~ magnetic structure pro- ~ -viding an elongated air gap 12 (in the form of a closed curve, or in sections of a closed curve) in combination with the diaphragm 14 ; --(having the edge thereof of the same stlape as the air gap 12) including a coil along its peripheral edge (formed to fit within che air gap 12) provides an arrangement wherein electromotive forces are transmitted between the pole pieces 24 and 26 and the diaphragm 14 over the entire, or portions of, t~Ze peripheral edge of the 20 diaphragm. The combination of the peripheral edge of the diaphragm and the coil attached thereto provides a large working area, wherein the entire~ or a large part of the peripheral edge 30 is exposed to the electromotive forces. This provides a highly-efficient arrangement, particularly at the high-frequency range. In the case wherein the transducer of the invention functions as a speaker, the high-frequency .. -, ~;:
.~ -21-, - . ~ , . . , . :- , -~U~ 7~
signals are generated along the entire circumference or peripheral edge of the diaphragm 14, thereby providing a substantially greater transducing area for the generation of high frequencies. As a result, the single diaphragm 14, in an electroacoustic transducer including the invention, provides a wide r ange of frequencies wherein ~ . .
the effectîve power output at the high-frequency range approaches ~ ~
that of the lower-frequency ranges. There is no need for "tweeter" ;~ ;;
speakers to accentuate the high frequencies~ The entire broad range of audio frequencies are generated by the single diaphragm 14. ~
In addition to the foregoing, it should be noted that since the high `
frequencies are generated at the circurmference or peripheral edge 30 of the diaphragm 14, the propagation of the high-frequency signals - -,, . - .
appears to be in all directions, essentially providing the effect of an omnidirectional speaker. This is because the direction of music and -sound is primarily detected by the human ear from the propagation of the high-frequency sounds. The propagation pattern of the high ;
frequencies from the electroacoustic transducer including the ~ `
invention approaches a pattern of 360 and therefore it is very diffi~
cult for the listener to detect the source of the sound.
In addition to the foregoing, the diaphragm 14 of the electroacoustic transducer including the invention can be made of a variety of thin, fairly-rigid materials, such as, for example, clear ~, ~
plastic or glass. VVith a clear plastic or glass diaphragm, the electroacoustic transducer appears as a hollow ring, or polygon~
shaped tube, with a clear "see-through" center. Eence, various , ~,, --2~
- , .
`'~ :':
i3-7~3 novelty items can be included within the speaker, such as, for example, lighting or color effects wherein the intensity of, and a - ~ -frequency of, illumination and color thereof i9 a function of the `~
amplitude and frequency of the sound being produced (psychedelic effects). Furthermore, the embodiment of the transducer of Figure 12 has the added advantage wherein the rectangular -diaphragm 14 and the elements forming the air gap 12 can be built about the front of a television tube with the clear diaphragm ~;
14 positioned across the face television tube. Such an arrange-10 ment provides a "see-through" speaker for viewing the television screen wherein the diaphragm functions as the source of sound ~-and a very large speaker, having extremely excellent acoustical fidelity, for television sets requiring very little extra space. ;
The embodiment of electromagnetic transducer illustrated in Figures 19 and 20 is described in the context of a transducer for use in control systems, such as, for example, lens focusing, or a pneumatic controller. The transducer includes an annular, tubular~
shaped magnet 100 (of the type specified above) providing the magnetic ;
flux for the transducer. The magnet 100 is secured between an outer ; ~
metallic sleeve 102 and an inner metallic sleeve 104, both of which ~ -extend beyond opposite ends of the magnet 100, The outer sleeve 102 includes the bends 106 and 108 so that the portions3~$~hhes~1eeee~102 and 104 that extend beyond the magnet 100 are brought in close proximity to define two annular, tubular-shaped air gaps 110 and 112. The dimensions of the air gaps 110 and 112 extending along the ~ 637~
direction of the axis 114 of the transducer and are substantially longer than the corresponding dimensions of the transducer of Figures 1 - 18 since it is movement, rather than sound, to be the input or output signal.
Separate current conduction means ~armatures 116 and 118) are positioned in separate ones of the air gaps and are mounted on the rings 120 and 122. The rings 120 and 122 include a plurality of tabs 124 which extend into the guideways 126 to pro-vide bearing surfaces for the armatures. The item to be controlled 10 is secured to the rings 120 and 122, For example, the coils 116 and 118 can be driven by a differential amplifier to provide a cor-responding differential movement from the coils. Alternatively, -the coils 116 and 118 can be driven in parallel and the coils con-nected to a lever mechanism in an aiding tandem management.
If the transducer is to beused in an optical system, the lens or -~
lenses can be secured to the rings 120 and 122. The armatures ~;
can be coupled to drive a single lens or can drive separate lenses.
In addition, similar transducers of the type illustrated in Figures 18 and 20 can be stacked in a tandem arrangement, so that the trans- ;
2G ducer can provide a variety of functions in response to a large com-bination of input signals. ; ~Ç
Although the transducer of Figures 19 and 20 is illustrated as having an annular tubular shape, it is to be understood that it can ; ~ -have a variety of tubular shapes, such as triangular, rectangular, oval, etc., depending upon the specific design requirements.
.... ... .
:L~3~
'' ~ '~ ' "
At times, the space provided for a control transducer may be limited and weight may be a problern, The air gap of the trans- ;
ducer of the invention can be increased by providing a serpentine type of configuration, such as the "U" shaped configuration of Figure 21 wherein the elongated length of the air gap is increased over that provided by the regular tubular-shaped configurations of Figures 1 - 20. As illustrated in Figure 21, the transducer includes an inner "U" shaped metallic element 130 and an outer "U" shaped metallic element 132 having a "U" shaped magnet structure (not shown) disposed therebetweenO A pair of "U" shaped ~ - ~
pole pieces 134 and 136 extend toward each other from the elements ~ 7 130 and 132 to define a continuous "U" shaped air gap 138 defining a closed curve. The armature for the transducer of Figure 21 will also have a "U" shape to conform with the air gap 138. As can be seen, since the length of the air gap 138 is greater than that pro~
vided by a tubular configuration of that of Figures 1 - 20, a greater working area is provided and, therefore, a greater output verses space is achieved by this arrangement. It should be understood with the transducer of the invention that any type of serpentine ;-closed curve air gap configuration can l~e provided, depending upon the design reqoirer.~erlts and the :pace avaiiable.
. ~, .
~ ' .
3L~ .
Claims (41)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An electroacoustic transducer comprising:
a diaphragm;
tubular shaped current conduction means secured to said diaphragm along a peripheral edge thereof;
concentric tubular shaped open ended magnetic flux translative elements providing at least one tubular shaped air gap therebetween for receiving said current conduction means, and permanent magnet means mounted between said elements so that said elements concentrate magnetic flux from said permanent magnet means through said air gap.
a diaphragm;
tubular shaped current conduction means secured to said diaphragm along a peripheral edge thereof;
concentric tubular shaped open ended magnetic flux translative elements providing at least one tubular shaped air gap therebetween for receiving said current conduction means, and permanent magnet means mounted between said elements so that said elements concentrate magnetic flux from said permanent magnet means through said air gap.
2. An electroacoustic transducer as defined in Claim 1 wherein:
said current conduction means has substantially the same shape as said air gap and extends within said air gap for move-ment transverse the flow of magnetic flux.
said current conduction means has substantially the same shape as said air gap and extends within said air gap for move-ment transverse the flow of magnetic flux.
3. An electroacoustic transducer as defined in Claim 2 wherein:
said diaphragm encloses at least the area enclosed by said current conduction means.
said diaphragm encloses at least the area enclosed by said current conduction means.
4. An electroacoustic transducer as defined in Claim 2 wherein:
said concentric elements have an annular tubular shape.
said concentric elements have an annular tubular shape.
5. An electroacoustic transducer as defined in Claim 2 wherein:
said concentric elements have the tubular shape of a polygon.
said concentric elements have the tubular shape of a polygon.
6. An electroacoustic transducer as defined in Claim 3 wherein:
said current conduction means comprises a coil.
said current conduction means comprises a coil.
7. An electroacoustic transducer as defined in Claim 3 wherein:
said current conduction means comprises a plurality of coils secured adjacent the peripheral edge of the diaphragm so that only one half of each coil extends within the air gap.
said current conduction means comprises a plurality of coils secured adjacent the peripheral edge of the diaphragm so that only one half of each coil extends within the air gap.
8. A transducer comprising:
a pair of tubular shaped magnetic flux translative elements mounted in a substantially concentric arrangement for providing therebetween at least one tubular shaped air gap, one of said pair of elements being open at both ends while the other one of said pair of elements being open at at least one end, and permanent magnet means mounted between said pair of elements for providing magnetic flux flow through said elements and said air gap;
current conduction means having a shape to fit within said air gap, and means for mounting said current conduction means so that at least a portion thereof extends within said air gap so that in response to a current flow through said current conduction means said current conduction means moves within said air gap.
a pair of tubular shaped magnetic flux translative elements mounted in a substantially concentric arrangement for providing therebetween at least one tubular shaped air gap, one of said pair of elements being open at both ends while the other one of said pair of elements being open at at least one end, and permanent magnet means mounted between said pair of elements for providing magnetic flux flow through said elements and said air gap;
current conduction means having a shape to fit within said air gap, and means for mounting said current conduction means so that at least a portion thereof extends within said air gap so that in response to a current flow through said current conduction means said current conduction means moves within said air gap.
9. A transducer as defined in Claim 8 wherein:
said pair of elements, said air gap, and said current conduction means have an annular tubular shape.
said pair of elements, said air gap, and said current conduction means have an annular tubular shape.
10. A transducer as defined in Claim 8 wherein:
said pair of elements, said air gap, and said current conduction means have a polygon tubular shape.
said pair of elements, said air gap, and said current conduction means have a polygon tubular shape.
11. An electroacoustic transducer comprising:
a stator including a pair of tubular shaped magnetic flux translative elements in concentric relation for providing at least one air gap therebetween having an elongated shape defining a closed curve and following the shape of the pair of elements, one of said pair of elements being open at both ends while the other one of said pair of elements being open at at least one end, and perma-nent magnet means mounted between said elements for providing magnetic flux flow through said elements and said air gap;
current conduction means having substantially the same shape as said air gap extending within said air gap;
diaphragm means, and means for securing said diaphragm means to said current conduction means adjacent the peripheral edge of said dia-phragm means.
a stator including a pair of tubular shaped magnetic flux translative elements in concentric relation for providing at least one air gap therebetween having an elongated shape defining a closed curve and following the shape of the pair of elements, one of said pair of elements being open at both ends while the other one of said pair of elements being open at at least one end, and perma-nent magnet means mounted between said elements for providing magnetic flux flow through said elements and said air gap;
current conduction means having substantially the same shape as said air gap extending within said air gap;
diaphragm means, and means for securing said diaphragm means to said current conduction means adjacent the peripheral edge of said dia-phragm means.
12. An electroacoustic transducer as defined in Claim 11 wherein:
said diaphragm covers at least the geometric area enclosed by said current conduction means.
said diaphragm covers at least the geometric area enclosed by said current conduction means.
13. An electroacoustic transducer comprising:
a stator, including a pair of tubular shaped magnetic flux translative elements arranged in a substantially concentric relation providing at least one air gap therebetween having an elongated configuration defining a closed curve substantially following the tubular shape of said pair of elements, one of said pair of ele-ments being open at both ends while the other one of said pair of elements being open at at least one end, and permanent magnet means mounted between said elements with poles of opposite polarity facing separate elements providing magnetic flux flow through a path including said pair of elements and said air gap;
current conduction means having substantially the same configuration as said elongated air gap and positioned therein for movement, in response to current flow therethrough, in a direc-tion transverse the flow of magnetic flux through said air gap, and diaphragm means connected to said current conduc-tion means adjacent the peripheral edge of the diaphragm means and having substantially the same shape of the area defined by the shape of said current conduction means.
a stator, including a pair of tubular shaped magnetic flux translative elements arranged in a substantially concentric relation providing at least one air gap therebetween having an elongated configuration defining a closed curve substantially following the tubular shape of said pair of elements, one of said pair of ele-ments being open at both ends while the other one of said pair of elements being open at at least one end, and permanent magnet means mounted between said elements with poles of opposite polarity facing separate elements providing magnetic flux flow through a path including said pair of elements and said air gap;
current conduction means having substantially the same configuration as said elongated air gap and positioned therein for movement, in response to current flow therethrough, in a direc-tion transverse the flow of magnetic flux through said air gap, and diaphragm means connected to said current conduc-tion means adjacent the peripheral edge of the diaphragm means and having substantially the same shape of the area defined by the shape of said current conduction means.
14. An electroacoustic transducer as defined in Claim 13 wherein:
said current conduction means is a coil, the winding thereof wound to extend in substantially the same direction as the elongated configuration of said air gap.
said current conduction means is a coil, the winding thereof wound to extend in substantially the same direction as the elongated configuration of said air gap.
15. An electroacoustic transducer as defined in Claim 13 wherein:
said current conduction means comprises a plurality of coils secured adjacent the peripheral edge of the diaphragm means so that only one half of each coil extends within the air gap.
said current conduction means comprises a plurality of coils secured adjacent the peripheral edge of the diaphragm means so that only one half of each coil extends within the air gap.
16. An electroacoustic transducer as defined in Claim 15 wherein:
the shape of the air gap is multisided and defines angles of 360 degrees enclosed therein.
the shape of the air gap is multisided and defines angles of 360 degrees enclosed therein.
17. An electroacoustic transducer as defined in Claim 14 wherein:
said elements and said air gap have the annular shape of a ring.
said elements and said air gap have the annular shape of a ring.
18. An electroacoustic transducer as defined in Claim 14 wherein:
said elements and said air gap have the shape of a polygon type tube.
said elements and said air gap have the shape of a polygon type tube.
19. An electroacoustic transducer as defined in Claim 14 wherein:
said elements and said air gap have the shape of a rectangular tube.
said elements and said air gap have the shape of a rectangular tube.
20. An electroacoustic transducer as defined in Claim 14 wherein:
said elements and said air gap have the shape of a tri-angular tube.
said elements and said air gap have the shape of a tri-angular tube.
21. An electroacoustic transducer comprising:
a first metallic element having an open ended tubular shape;
a second metallic element, having substantially the same tubular shape as said first element but having smaller dimen-sions so that the second element is positioned in a substantially concentric relation within said first element;
permanent magnet means mounted between the first and second elements and adjacent one end of each of said elements so that the other end of each of said first and second elements define an air gap therebetween and wherein magnetic flux flows from said permanent magnet means through a path including said elements and said air gap;
current conduction means, having substantially the same configuration as said air gap, mounted for movement within said air gap, and diaphragm means, having substantially the same geo-metric configuration as the area enclosed by said current conduction means, extending across said current conduction means and attached thereto.
a first metallic element having an open ended tubular shape;
a second metallic element, having substantially the same tubular shape as said first element but having smaller dimen-sions so that the second element is positioned in a substantially concentric relation within said first element;
permanent magnet means mounted between the first and second elements and adjacent one end of each of said elements so that the other end of each of said first and second elements define an air gap therebetween and wherein magnetic flux flows from said permanent magnet means through a path including said elements and said air gap;
current conduction means, having substantially the same configuration as said air gap, mounted for movement within said air gap, and diaphragm means, having substantially the same geo-metric configuration as the area enclosed by said current conduction means, extending across said current conduction means and attached thereto.
22. An electroacoustic transducer as defined in Claim 21 wherein:
said diaphragm means has the general shape of a disc.
said diaphragm means has the general shape of a disc.
23. An electroacoustic transducer as definéd in Claim 21 wherein:
said first and second elements, said air gap, and said current conduction means, have the shape of a polygon shaped tube.
said first and second elements, said air gap, and said current conduction means, have the shape of a polygon shaped tube.
24. An electroacoustic transducer as defined in Claim 23 wherein:
said first and second elements, said air gap, and said current conduction means, have a substantially triangular tubular shape.
said first and second elements, said air gap, and said current conduction means, have a substantially triangular tubular shape.
25. An electroacoustic transducer as defined in Claim 24 wherein:
said first and second elements, said air gap, and said current conduction means, have a substantially rectangular tubular shape.
said first and second elements, said air gap, and said current conduction means, have a substantially rectangular tubular shape.
26. An electroacoustic transducer comprising:
a stator including a plurality of tubular shaped open ended magnetic flux translative elements positioned in a substantially concentric relation for providing two separate air gaps that have sub-stantially the same tubular shape as said elements and are located adjacent and parallel to each other with a separation in between, and permanent magnet means mounted between said elements to pro-vide magnetic flux flow through said elements and said air gaps;
current conduction means, having substantially the same configuration as said air gaps;
means for mounting said current conduction means so that said current conduction means extends within both air gaps for free movement, in response to a current flow therethrough, in a direction transverse the direction of magnetic flux flow through said air gaps, and diaphragm means connected to said current conduction means adjacent the peripheral edge of the diaphragm means enclosing at least the area defined by the shape of the current conduction means and extending through said separation between said air gaps.
a stator including a plurality of tubular shaped open ended magnetic flux translative elements positioned in a substantially concentric relation for providing two separate air gaps that have sub-stantially the same tubular shape as said elements and are located adjacent and parallel to each other with a separation in between, and permanent magnet means mounted between said elements to pro-vide magnetic flux flow through said elements and said air gaps;
current conduction means, having substantially the same configuration as said air gaps;
means for mounting said current conduction means so that said current conduction means extends within both air gaps for free movement, in response to a current flow therethrough, in a direction transverse the direction of magnetic flux flow through said air gaps, and diaphragm means connected to said current conduction means adjacent the peripheral edge of the diaphragm means enclosing at least the area defined by the shape of the current conduction means and extending through said separation between said air gaps.
27. An electromagnetic transducer comprising:
a stator including a pair of concentric tubular shaped magnetic flux translative elements defining an air gap in between having substantially the same tubular shape as said elements, one of said elements being open at both ends while the other end of said pair of elements being open at at least one end, a plurality of separators dividing said air gap into a plurality of separate air gap sections, and permanent magnet means mounted between said elements for providing magnetic flux flow through a path including said elements and said air gap, and current conduction means having substantially the same configuration as said air gap with portions thereof extending into said plurality of air gap sections, said current conduction means being responsive to the flow of current therethrough to create forces on the current conduction means to move the current conduction means in a direction transverse the magnetic flux lines in the air gap sections.
a stator including a pair of concentric tubular shaped magnetic flux translative elements defining an air gap in between having substantially the same tubular shape as said elements, one of said elements being open at both ends while the other end of said pair of elements being open at at least one end, a plurality of separators dividing said air gap into a plurality of separate air gap sections, and permanent magnet means mounted between said elements for providing magnetic flux flow through a path including said elements and said air gap, and current conduction means having substantially the same configuration as said air gap with portions thereof extending into said plurality of air gap sections, said current conduction means being responsive to the flow of current therethrough to create forces on the current conduction means to move the current conduction means in a direction transverse the magnetic flux lines in the air gap sections.
28. An electromagnetic transducer as defined in Claim 27 including:
a diaphragm, having the configuration of the area enclosed by said air gap, attached to said current conduction means so that the transducer functions as an electroacoustic transducer.
a diaphragm, having the configuration of the area enclosed by said air gap, attached to said current conduction means so that the transducer functions as an electroacoustic transducer.
29. An electromagnetic transducer as defined in Claim 27 wherein:
said current conduction means includes a continuous coil wound in a direction following said air gap with portions thereof bent to avoid the separators in the air gap.
said current conduction means includes a continuous coil wound in a direction following said air gap with portions thereof bent to avoid the separators in the air gap.
30. An electromagnetic transducer as defined in Claim 27 wherein:
said current conduction means includes a plurality of coils, a separate one for each of the plurality of air gaps, said coils being positioned within the associated air gaps so that the windings of one-half said coils extend within the air gaps.
said current conduction means includes a plurality of coils, a separate one for each of the plurality of air gaps, said coils being positioned within the associated air gaps so that the windings of one-half said coils extend within the air gaps.
31. An electromagnetic transducer comprising:
tubular shaped permanent magnet means having exterior and interior magnetic poles of opposite magnetic polarity;
a first pole piece, having a tubular shape, surrounding the exterior of the magnet means and extending beyond the magnet means along the axial tubular direction of the magnet means, a second pole piece, having a tubular shape, abutting the interior of the magnet means and extending in the same direction as said first pole piece to define a tubular shaped air gap there-between, the arrangement being such that magnetic flux from said permanent magnet means flows through a path including said first and second pole pieces and said air gap, and current conduction means having substantially the same tubular shape as said air gap and positioned therein so that in response to a current flow therethrough a force is created to move the current conduction means along said air gap.
tubular shaped permanent magnet means having exterior and interior magnetic poles of opposite magnetic polarity;
a first pole piece, having a tubular shape, surrounding the exterior of the magnet means and extending beyond the magnet means along the axial tubular direction of the magnet means, a second pole piece, having a tubular shape, abutting the interior of the magnet means and extending in the same direction as said first pole piece to define a tubular shaped air gap there-between, the arrangement being such that magnetic flux from said permanent magnet means flows through a path including said first and second pole pieces and said air gap, and current conduction means having substantially the same tubular shape as said air gap and positioned therein so that in response to a current flow therethrough a force is created to move the current conduction means along said air gap.
32. An electromagnetic transducer as defined in Claim 31 wherein:
said first and second pole pieces extend beyond the permanent magnet means, along the axial tubular direction, and on both sides of the permanent magnet means to provide two separate tubular shaped air gaps, and said current conduction means, includes two units each having substantially the same shape as said air gaps and positioned in separate ones of the air gaps.
said first and second pole pieces extend beyond the permanent magnet means, along the axial tubular direction, and on both sides of the permanent magnet means to provide two separate tubular shaped air gaps, and said current conduction means, includes two units each having substantially the same shape as said air gaps and positioned in separate ones of the air gaps.
33. An electromagnetic transducer as defined in Claim 31, including:
guide means for said current conduction means for controlling the linear movement of said current conduction means in said air gap.
guide means for said current conduction means for controlling the linear movement of said current conduction means in said air gap.
34. An electromagnetic transducer comprising:
stator means including first and second open ended tubular shaped magnetic flux translative elements, the second element having smaller dimensions than the first so that the second element is positioned in a substantially concentric relation within said first element to form a hollow structure, said first and second elements being shaped so that a first end of each of the first and second elements is spaced further apart than a second end of each of said first and second elements, wherein the spacing between said second ends define an air gap, and permanent magnet means positioned between said first and second elements with opposite poles facing separate ones of the first and second elements so that a path for magnetic flux flow from the permanent magnet means includes the first and second elements and the air gap, and current conduction means, having substantially the same shape as said air gap, positioned therein.
stator means including first and second open ended tubular shaped magnetic flux translative elements, the second element having smaller dimensions than the first so that the second element is positioned in a substantially concentric relation within said first element to form a hollow structure, said first and second elements being shaped so that a first end of each of the first and second elements is spaced further apart than a second end of each of said first and second elements, wherein the spacing between said second ends define an air gap, and permanent magnet means positioned between said first and second elements with opposite poles facing separate ones of the first and second elements so that a path for magnetic flux flow from the permanent magnet means includes the first and second elements and the air gap, and current conduction means, having substantially the same shape as said air gap, positioned therein.
35. An electromagnetic transducer as defined in Claim 34 wherein:
the cross-sectional shape of said first and second elements, in the direction of magnetic flux flow, is substantially in the shape of a "U" with the first ends of the first and second elements forming the open end of the "U" and with the air gap located in the "U" shaped structure.
the cross-sectional shape of said first and second elements, in the direction of magnetic flux flow, is substantially in the shape of a "U" with the first ends of the first and second elements forming the open end of the "U" and with the air gap located in the "U" shaped structure.
36. An electromagnetic transducer as defined in Claim 34 wherein:
the cross-sectional area of said permanent magnet means, transverse the direction of magnetic flux flow, is substan-tially greater than the cross-sectional area of the air gap, transverse the direction of magnetic flux flow, thereby providing a magnetic flux concentration in said air gap.
the cross-sectional area of said permanent magnet means, transverse the direction of magnetic flux flow, is substan-tially greater than the cross-sectional area of the air gap, transverse the direction of magnetic flux flow, thereby providing a magnetic flux concentration in said air gap.
37. An electromagnetic transducer as defined in Claim 34 wherein:
at least one of said first and second elements have a tubular shaped extension at its second end thereof wherein the exten-sion forms said air gap with said other of said first and second elements.
at least one of said first and second elements have a tubular shaped extension at its second end thereof wherein the exten-sion forms said air gap with said other of said first and second elements.
38. An electromagnetic transducer as defined in Claim 34 including:
diaphragm means connected at its peripheral edge to said current conduction means.
diaphragm means connected at its peripheral edge to said current conduction means.
39. An electromagnetic transducer comprising:
stator means including first and second tubular shaped open ended magnetic flux translative elements, the second element having smaller dimensions than the first element so that the second element is positioned in a substantially concentric relation within the second element, first and second tubular shaped pole pieces extending from said first and second elements, respectively, and adjacent one end thereof so that said first and second pole pieces define a tubular shaped air gap therebetween, and permanent magnet means mounted between said first and second elements with opposite poles facing separate ones of first and second elements so that magnetic flux flows from said permanent magnet means through a path including the first and second elements and said air gap, the cross-sectional area of the permanent magnet means, transverse the direction of magnetic flux flow, is substantially greater than the cross-sectional area of the air gap, transverse the direction of magnetic flux flow, and current conduction means, having substantially the same tubular shape as said air gap, movably mounted in said air gap.
stator means including first and second tubular shaped open ended magnetic flux translative elements, the second element having smaller dimensions than the first element so that the second element is positioned in a substantially concentric relation within the second element, first and second tubular shaped pole pieces extending from said first and second elements, respectively, and adjacent one end thereof so that said first and second pole pieces define a tubular shaped air gap therebetween, and permanent magnet means mounted between said first and second elements with opposite poles facing separate ones of first and second elements so that magnetic flux flows from said permanent magnet means through a path including the first and second elements and said air gap, the cross-sectional area of the permanent magnet means, transverse the direction of magnetic flux flow, is substantially greater than the cross-sectional area of the air gap, transverse the direction of magnetic flux flow, and current conduction means, having substantially the same tubular shape as said air gap, movably mounted in said air gap.
40. An electromagnetic transducer as defined in Claim 39 including:
diaphragm means connected along its peripheral edge to said current conduction means.
diaphragm means connected along its peripheral edge to said current conduction means.
41. An electromagnetic transducer as defined in Claim 40 wherein:
said first and second elements, said first and second pole pieces, said air gap, and said current conduction means have a serpentine tubular shape.
said first and second elements, said first and second pole pieces, said air gap, and said current conduction means have a serpentine tubular shape.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB3599676A GB1550924A (en) | 1976-08-31 | 1976-08-31 | Electromagnetic transducer |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1063710A true CA1063710A (en) | 1979-10-02 |
Family
ID=10383827
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA258,938A Expired CA1063710A (en) | 1976-08-31 | 1976-08-12 | Electromagnetic transducer |
Country Status (3)
| Country | Link |
|---|---|
| CA (1) | CA1063710A (en) |
| DE (1) | DE2637412A1 (en) |
| GB (1) | GB1550924A (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2129186A (en) * | 1982-10-29 | 1984-05-10 | Atasi Corp | Disk drive actuator structure |
| DE4016741C1 (en) * | 1990-05-21 | 1991-06-20 | Mannesmann Ag, 4000 Duesseldorf, De | |
| US5182481A (en) * | 1990-05-28 | 1993-01-26 | Sony Corporation | Voice coil type actuator |
| JP2751567B2 (en) * | 1990-05-28 | 1998-05-18 | ソニー株式会社 | Voice coil type actuator |
| JPH06233379A (en) * | 1993-02-02 | 1994-08-19 | Kenwood Corp | Speaker |
| KR19990037725A (en) | 1995-09-02 | 1999-05-25 | 헨리 에이지마 | Display means combined with loudspeakers |
| JP2002281135A (en) * | 2001-03-21 | 2002-09-27 | Nec Viewtechnology Ltd | Portable telephone |
-
1976
- 1976-08-12 CA CA258,938A patent/CA1063710A/en not_active Expired
- 1976-08-19 DE DE19762637412 patent/DE2637412A1/en not_active Ceased
- 1976-08-31 GB GB3599676A patent/GB1550924A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| GB1550924A (en) | 1979-08-22 |
| DE2637412A1 (en) | 1978-02-23 |
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