US2506624A - Electroacoustic transducer - Google Patents

Electroacoustic transducer Download PDF

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Publication number
US2506624A
US2506624A US755397A US75539747A US2506624A US 2506624 A US2506624 A US 2506624A US 755397 A US755397 A US 755397A US 75539747 A US75539747 A US 75539747A US 2506624 A US2506624 A US 2506624A
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US
United States
Prior art keywords
pole
magnet
cylindrical
armature
flange
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US755397A
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English (en)
Inventor
Robert E Wirsching
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
AT&T Corp
Original Assignee
Bell Telephone Laboratories Inc
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Priority to BE481098D priority Critical patent/BE481098A/xx
Priority to NL71197D priority patent/NL71197C/xx
Priority to FR963471D priority patent/FR963471A/fr
Application filed by Bell Telephone Laboratories Inc filed Critical Bell Telephone Laboratories Inc
Priority to US755397A priority patent/US2506624A/en
Priority to GB16314/48A priority patent/GB653923A/en
Priority to DEP28875D priority patent/DE813164C/de
Application granted granted Critical
Publication of US2506624A publication Critical patent/US2506624A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R11/00—Transducers of moving-armature or moving-core type
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R13/00—Transducers having an acoustic diaphragm of magnetisable material directly co-acting with electromagnet

Definitions

  • FIGu Z This invention relates Patented May 9, 1950 ELECTRGACOUSTIC TRANSDUCER Robert E. Wrsching, Chatham, N. J., assigner to Bell Telephone Laboratories, Incorporated, New York, N. Y., a corporation of New York Application June 18, 1947, Serial No. 755,397
  • the magnetic system includes two magnetic circuits each of which comprises a permanent magnet and also an annular armature common to the two circuits.
  • the armature is supported adjacent its outer portion and has its inner marginal portion extending into an air gap between juxtaposed magnetic parts of the two circuits.
  • the magnets in the two circuits are relatively poled so that the components of ux through the armature due thereto are in opposition.
  • Realization of optimum performance by such 'construction entails manufacture of the parts constituting the magnetic system to close tolerances.
  • the magnetic system comprises a relatively large number of parts so that the structure is somewhat complex and attainment of the desired relation of the parts involves manufacturing control of a correspondingly large number of parts.
  • One object of this invention is to simplify the structure and facilitate the manufacture of ring armature type transducers.
  • objects of this invention are to reduce the requisite number of elements or :parts in magnetic systems for transducers of the general construction above-described, to expedite the realization of the correlation of the elements or parts to assure optimum performance,
  • the support member is of non-magnetic non-metallic material So that eddycurrent losses in the magnetic system are minimized.
  • Fig. 1 is a side'view section of an electroacoustic transducer illustrative of one embodi- 'ment of this invention
  • Fig. 2 is a detail diagrammatic view illustrating the direct current and signal ux paths in the transducer shown in Fig. 1, and
  • Fig. 3 is a fragmentary sectional view illustrating another embodiment of this invention.
  • the device therein illustrated is operable as either a receiver or transmitter and comprises a pole-piece having an annular base Io and a cylindrical pole tip portion II, the 'pole-piece being of a material, such as the nickel-iron alloy known commercially as Permalloy, having a high permeability.
  • a pole-piece i3, II is associated with the pole-piece i3, II and an annular permanent magnet having a cylindrical portion I2 coaxial with the pole tip portion I I and seated upon the base I0 and an integral annular flange I3 the inner marginal part of which is opposite and coaxial with the tip of the pole-piece portion I i.
  • the magnet is of a high coercive force material such as the aluminum-nickel-cobaltiron alloy known commercially as Alnco or the molybdenum-cobalt-iron alloy known commercially as Remalloy.
  • a cylindrical non-magnetic support I4 is seated upon and nrmly afxed to the base I0, is tted within the magnet part I2 and has its other end coplanar with the tip face of the pole-piece p0rtion II.
  • the support is of a non-metallic material which is easily machinable so that the free end face thereof may be readily operated upon, e. g. ground, to make it accurately copla-nar with the pole tip face.
  • a suitable and illustrative material is a phenolic condensation product.
  • annular magnetic spacer I5 Seated upon and aixed to the support I4 is an annular magnetic spacer I5, for example of Permalloy, which is fitted within the cylindrical lpart I 2 of the magnet and forms a seat for the armature I B.
  • the armature which also may be of Permalloy, is annular, has its periphery immediately adjacent the magnet and has'its inner marginal portion coaxial with and in juxtaposition to the face of the pole tip portion II.
  • the armature mounts a dished, lightweight non-magnetic diaphragm I7, for example of thin metal such as Duralumin, a plastic such as polystyrene, or a fabric impregnated with a phenolic condensation product.
  • a centrally dished and apertured disc or grid I9 is seated upon the flange I3 and serves to protect the diaphragm I'I.
  • At the other end ofthe s corture is an insulating pla-te 20 mounting terminals 2
  • the severalparts of the structure specilcaliy the magnet', pole-piece, grid and terminal are firmly held together in pile-up relation by a ID.
  • the support provides eddy current shielding of the magnet part I2.
  • clamping band 24 having its ends bearing against between the armature andv the poleztip'face.
  • the Amagnetic system of.; the transducer comprises two circuitsfior branchesfhaving the arma- HLLIIV and major partof portion I 2 ofthe permanent magnet.
  • I3 is magnetizedto produce lpoles .ci opposite polarity atits extremities-as lindicated at N ands in FigiA 2. Then acurrent is: supplied-to the coil ZZ-in the. direction to demagnetizeV the magnet part vI2A thereof, in steps ⁇ to the point corresponding .to maximum eiiiciency.
  • thearmature support /comprises a cylindrical part H3A ntted within they magnet portion I-2 and an annular iiange-g-IAB seated'upon and aixed to the base iiange IU .of the pole-piece.
  • the support maybe, of insulating material and have its portion IB, ⁇ cemented to thepole-piece "flange It.
  • the support may be ⁇ of Jagfhigh resistivity metal havingslight permeability and have its portion IIB welded'to the ange
  • the free endof the supportk portionzIlIA and the tip of pole-piece portion I l are ground plane and are in parallel planes, and the armature IB is seated directly upon the support I4.
  • the free end of magnet part l2 is ground to establish a prescribed distance between .the plane of this end and the magnet-part I3.
  • the free end of support portion IGA is ground to x the distance thereof frornfthewireeend of magnet part I2 at a prescribed value.
  • the tip of pole-piece portionY I l is ground so that it is in a plane a preassigned distance fromthe plane of the free end ci support portion 14A. Consequently, when .the
  • the magnet is magnetizedto produce poles atfitslextremes-and then is -demagnetizedsectionally to establish the desired unbalance between thel two-circuits-.cr branches of the magnetic system ⁇ and. realize maximum eiiiciency ⁇ and a ⁇ desirable operating stability.
  • l. .en electroaccustic.transducer comprisinga pcie-piece navi-nga. base'and a cylindrical portion extending from said base, av magnet. having. .-.a cylindrical portion Vextending from said ⁇ basearld coaxial with-said cylindrical portion of saidpolepiece, saidmagnet having-also a ange" portion in juxtaposition to said cylindrical portionotVv said pole-piece and dening an air -gap therewith, an annular armaturehaving one .margin adjacent a part ci said .magnet intermediate the ⁇ poles thereof and having a portionextending. intosaid-air and meanssupporting saidv armaturefor vibratorymotion of said portionthereof. y
  • An electroacoustictransducer comprising a magnet having a cylindrical portionand .an annular fiange Vextending inwardly -from .one end of said cylindrical portiorna pole-piece.v extending inwardly from theother endr of sa-idicylin.- drical portion and havingan annular poletipin juxtaposition to said ange and -deflninganair gap therewith, an annular armaturehaving.- its periphery adjacent said cylindrical portion of said magnet vand having a-portion in said air gap, and means supporting said armature adjacent said periphery thereof.
  • ⁇ An electroacoustic transducer comprising a pole-piece .having a. base and.. a pole. tip v.portion extending. from said. base, a. magnet. hai/inge portion one end of whichis adjacent saidbase and having also. a flange extending from ⁇ the other end of' said' portion. saidange Yhavinglits free end in juxtaposition to said pole ,tip .portion and deiining an air gap therewith, said magnet ⁇ being .magnetized ⁇ toQproduce polesofv opposite said air gap.
  • An'r electroacoustic" transd'ucerVVV comprising a magnetY having a cylindrical portion and-anannular flange extending from one end of said cylindrical portion, a pole-piece having a base extending from the other end of said cylindrical portion and having also a cylindrical pole tip in juxtaposition to and coaxial with the free end of said flange and defining an air gap therewith, said magnet being magnetized locally to produce poles of opposite polarity at said one end thereof and said end of said flange and such that said cylindrical portion and flange are 'of unequal strength, an annular armature having one margin immediately adjacent the junction of said cylindrical portion and flange and its other margin in said air gap, and means supporting said armature adjacent said one margin thereof.
  • An electroacoustic transducer comprising a magnet having a cylindrical portion and an annular flange extending inwardly from said cylindrical portion, a pole-piece comprising a base extending inwardly from one end of said cylindrical portion ⁇ and a cylindrical pole tip portion coaxial with said flange and terminating in a tip in juxtaposition to the inner margin of said flange and defining an air gap therewith, said magnet being magnetized locally to produce poles of unlike polarity at said one end and margin and such that said cylindrical portion is more highly magnetized than said flange, an annular armature having its outer edge adjacent the junction of said cylindrical portion and flange and its inner edge portion in said air gap, and means supporting said armature adjacent said outer edge thereof.
  • An electroacoustic transducer comprising a pole-piece having a cylindrical portion terminating in a pole tip and having also a iiange extending from said cylindrical portion, a magnet having a cylindrical part seated upon said flange and spaced from said cylindrical pole-piece portion and having also a flange overlying said pole tip and defining an air gap therewith, a cylindrical support between said cylindrical magnet part and said cylindrical pole-piece portion, and an annular armature seated adjacent one margin upon said support and extending into said air gap.
  • An electroacoustic transducer comprising a magnet having a cylindrical portion and an annular flange extending from one end of said cylindrical portion, an annular armature having one margin adjacent said cylindrical portion and its other margin opposite the free end of said flange, said flange and armature together with the gap therebetween and a portion of said cylindrical portion defining a first magnetic circuit, a pole-piece extending from the other end of said cylindrical portion and having a pole tip in juxtaposition tc said other margin of said armature, said pole-piece and armature together with the gap therebetween and the remainder of said cylindrical magnet portion defining a second magnetic circuit, and a signal coil linked to said second circuit, said magnet being magnetized to produce poles of unlike polarity at said other end of said cylindrical portion and said free end of said flange and such that the direct current inagnetomotive force in said second circuit is greater than that in said first circuit.
  • An electroacoustic transducer comprising a permanent magnet having a cylindrical portion and an annular iiange extending inwardly from one end of said cylindrical portion, a pole-piece extending inwardly from the other end of said cylindrical portion and having an annular pole tip in juxtaposition to and coaxial with the inner margin of said flange, an annular armature having its periphery adjacent said one end of said cylindrical portion and having its inner marginal part in the gap between said pole tip and said inner margin of said flange, and a signal coil linked to said pole-piece, said magnet being magnetized to produce poles of unlike polarity at said other end of said cylindrical portion and at said inner margin of said flange and such that the direct current flux in the magnetic circuit including said armature and said pole-piece exceeds that in the magnetic circuit including said armature and said flange.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Audible-Bandwidth Dynamoelectric Transducers Other Than Pickups (AREA)
  • Permanent Field Magnets Of Synchronous Machinery (AREA)
US755397A 1947-06-18 1947-06-18 Electroacoustic transducer Expired - Lifetime US2506624A (en)

Priority Applications (6)

Application Number Priority Date Filing Date Title
BE481098D BE481098A (enrdf_load_stackoverflow) 1947-06-18
NL71197D NL71197C (enrdf_load_stackoverflow) 1947-06-18
FR963471D FR963471A (enrdf_load_stackoverflow) 1947-06-18
US755397A US2506624A (en) 1947-06-18 1947-06-18 Electroacoustic transducer
GB16314/48A GB653923A (en) 1947-06-18 1948-06-17 Improvements in or relating to electro-acoustic transducers
DEP28875D DE813164C (de) 1947-06-18 1948-12-31 Elektroakustischer UEbertrager

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US755397A US2506624A (en) 1947-06-18 1947-06-18 Electroacoustic transducer

Publications (1)

Publication Number Publication Date
US2506624A true US2506624A (en) 1950-05-09

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Family Applications (1)

Application Number Title Priority Date Filing Date
US755397A Expired - Lifetime US2506624A (en) 1947-06-18 1947-06-18 Electroacoustic transducer

Country Status (6)

Country Link
US (1) US2506624A (enrdf_load_stackoverflow)
BE (1) BE481098A (enrdf_load_stackoverflow)
DE (1) DE813164C (enrdf_load_stackoverflow)
FR (1) FR963471A (enrdf_load_stackoverflow)
GB (1) GB653923A (enrdf_load_stackoverflow)
NL (1) NL71197C (enrdf_load_stackoverflow)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2535757A (en) * 1946-06-25 1950-12-26 John J Root Peripherally driven electroacoustical transducer
US2567365A (en) * 1948-08-04 1951-09-11 Bell Telephone Labor Inc Polarized operator for telephone receivers
US2717096A (en) * 1953-01-23 1955-09-06 Minnis W Henderson Magnet gas tank cap
US4075437A (en) * 1976-07-16 1978-02-21 Bell Telephone Laboratories, Incorporated Composition, processing and devices including magnetic alloy
US4174983A (en) * 1978-07-13 1979-11-20 Bell Telephone Laboratories, Incorporated Fe-Cr-Co magnetic alloy processing
US4258234A (en) * 1979-08-24 1981-03-24 Bell Telephone Laboratories, Incorporated Electroacoustic device
US4311537A (en) * 1980-04-22 1982-01-19 Bell Telephone Laboratories, Incorporated Low-cobalt Fe-Cr-Co permanent magnet alloy processing
US4425482A (en) 1982-03-08 1984-01-10 Western Electric Company Ring armature electroacoustic transducer
US4443667A (en) * 1982-01-11 1984-04-17 Bell Telephone Laboratories, Incorporated Electromagnetic transducer
EP0266834A1 (en) * 1986-10-29 1988-05-11 Koninklijke Philips Electronics N.V. Oscillating motor

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3819771A1 (de) * 1987-12-18 1989-07-06 Karl Scheffer Klute Gmbh & Co Handluftpumpe fuer zweiradreifen

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1228639A (en) * 1914-03-27 1917-06-05 Erik Christian Bayer Sound-producing device.
US1579605A (en) * 1925-10-17 1926-04-06 Gavin Percy Radio amplifying receiver
US1895071A (en) * 1928-09-25 1933-01-24 Herman J Fanger Dynamic loud speaker unit
US1951531A (en) * 1931-02-12 1934-03-20 Rca Corp Sound-translating device
US2170571A (en) * 1936-08-12 1939-08-22 Bell Telephone Labor Inc Acoustic device
US2249160A (en) * 1939-05-19 1941-07-15 Bell Telephone Labor Inc Acoustic device
US2395166A (en) * 1942-12-24 1946-02-19 Astatic Corp Transducer

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1228639A (en) * 1914-03-27 1917-06-05 Erik Christian Bayer Sound-producing device.
US1579605A (en) * 1925-10-17 1926-04-06 Gavin Percy Radio amplifying receiver
US1895071A (en) * 1928-09-25 1933-01-24 Herman J Fanger Dynamic loud speaker unit
US1951531A (en) * 1931-02-12 1934-03-20 Rca Corp Sound-translating device
US2170571A (en) * 1936-08-12 1939-08-22 Bell Telephone Labor Inc Acoustic device
US2249160A (en) * 1939-05-19 1941-07-15 Bell Telephone Labor Inc Acoustic device
US2395166A (en) * 1942-12-24 1946-02-19 Astatic Corp Transducer

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2535757A (en) * 1946-06-25 1950-12-26 John J Root Peripherally driven electroacoustical transducer
US2567365A (en) * 1948-08-04 1951-09-11 Bell Telephone Labor Inc Polarized operator for telephone receivers
US2717096A (en) * 1953-01-23 1955-09-06 Minnis W Henderson Magnet gas tank cap
US4075437A (en) * 1976-07-16 1978-02-21 Bell Telephone Laboratories, Incorporated Composition, processing and devices including magnetic alloy
US4174983A (en) * 1978-07-13 1979-11-20 Bell Telephone Laboratories, Incorporated Fe-Cr-Co magnetic alloy processing
US4258234A (en) * 1979-08-24 1981-03-24 Bell Telephone Laboratories, Incorporated Electroacoustic device
US4311537A (en) * 1980-04-22 1982-01-19 Bell Telephone Laboratories, Incorporated Low-cobalt Fe-Cr-Co permanent magnet alloy processing
US4443667A (en) * 1982-01-11 1984-04-17 Bell Telephone Laboratories, Incorporated Electromagnetic transducer
US4425482A (en) 1982-03-08 1984-01-10 Western Electric Company Ring armature electroacoustic transducer
EP0266834A1 (en) * 1986-10-29 1988-05-11 Koninklijke Philips Electronics N.V. Oscillating motor

Also Published As

Publication number Publication date
FR963471A (enrdf_load_stackoverflow) 1950-07-11
BE481098A (enrdf_load_stackoverflow)
NL71197C (enrdf_load_stackoverflow)
DE813164C (de) 1951-09-10
GB653923A (en) 1951-05-30

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