US3755699A - Electro-mechanical transducer - Google Patents

Electro-mechanical transducer Download PDF

Info

Publication number
US3755699A
US3755699A US00261790A US3755699DA US3755699A US 3755699 A US3755699 A US 3755699A US 00261790 A US00261790 A US 00261790A US 3755699D A US3755699D A US 3755699DA US 3755699 A US3755699 A US 3755699A
Authority
US
United States
Prior art keywords
bobbin
end cheeks
pair
cheeks
moving coil
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
US00261790A
Other languages
English (en)
Inventor
J Cartwright
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.)
Vickers Inc
Original Assignee
Sperry Rand Ltd
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
Application filed by Sperry Rand Ltd filed Critical Sperry Rand Ltd
Application granted granted Critical
Publication of US3755699A publication Critical patent/US3755699A/en
Assigned to VICKERS, INCORPORATED reassignment VICKERS, INCORPORATED ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: SPERRY LIMITED
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • 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
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F7/00—Magnets
    • H01F7/06—Electromagnets; Actuators including electromagnets
    • H01F7/066—Electromagnets with movable winding
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F7/00—Magnets
    • H01F7/06—Electromagnets; Actuators including electromagnets
    • H01F7/08—Electromagnets; Actuators including electromagnets with armatures
    • H01F7/16—Rectilinearly-movable armatures
    • H01F7/1607—Armatures entering the winding
    • H01F7/1615—Armatures or stationary parts of magnetic circuit having permanent magnet
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F7/00—Magnets
    • H01F7/06—Electromagnets; Actuators including electromagnets
    • H01F7/08—Electromagnets; Actuators including electromagnets with armatures
    • H01F7/121—Guiding or setting position of armatures, e.g. retaining armatures in their end position
    • H01F7/122—Guiding or setting position of armatures, e.g. retaining armatures in their end position by permanent magnets

Definitions

  • the present invention relates to electro-mechanical transducers of the kind designed primarily to produce an output force in response to an electrical input.
  • Transducers of this kind are used, for example, in hydraulic systems where the operation of the system may be controlled by means of a pilot valve in which a hydraulic pressure difference is balanced by an externally applied force.
  • a torque motor which consists of an electric motor arranged so as to be capable of being operated in a continuously stalled condition. If a linear force is required instead of a torque, a crank is attached to the armature shaft.
  • Such torque motors are frequently large and heavy in relation to the output force attainable, and have a large inertia, making them unsuitable for applications in which rapid response is required.
  • An alternative arrangement comprises a moving coil positioned in the gap of a pot magnet, but this arrangement is limited in the power output available and may be expensive to construct because of the accuracy of machining required.
  • One form of the present invention provides a linear force motor capable of giving a substantial force output with reasonably low inertia, and is relatively inexpensive to manufacture.
  • a moving coil transducer comprises a bobbin of magnetically soft ferro-magnetic material having a cylindrical portion wound with an actuating winding between end cheeks, each of the end cheeks being disposed in the gap between a pair of pole pieces comprising parallel plates having apertures shaped to admit the end cheeks and spaced apart at a distance approximately equal tolthe thickness of the end cheeks.
  • the bobbin is supported with its end cheeks in the pole piece gap by a pair of flexible diaphragms, the spring stiffness of the diaphragms providing the restoring force to maintain the end cheeks centralised in the pole piece gaps when no current is flowing through the actuating winding.
  • an axial rod of non-magnetic material passes centrally through the iron bobbin and is screwed at the end to take clamping nuts by means of which the bobbin is clamped to the diaphragms.
  • the transducer For the transducer to have a linear current/force characteristic, it is necessary to keep the pole pieces constantly magnetised with the innermost pole pieces being of one polarity, and the outermost of the opposite polarity.
  • the innermost pair of pole pieces are connected by soft iron yokes, and the outermost pair are connected by soft iron yokes, and permanent magnets are arranged between the yokes of the inner pair and the yokes of the outer pair, thus maintaining the pole pieces with the required polarities.
  • This arrangement has the advantage of providing a low reluctance return flux path through the pole pieces and yokes for the magnetisation of the bobbin.
  • the innermost pole piece at each end may be coupled to the outermost pole piece of the other by means of a core carrying a magnetising winding.
  • these windings are energised by an electric current so as to produce the required polarities at the pole pieces.
  • transducer can be caused to operate with a linear force/current characteristic, its sensitivity being adjustable by varying the current through the magnetising windings.
  • the transducer will have a square-law characteristic.
  • the motor may be supplied with alternating current in this case, provided that the frequency of the alternating current is high in relation to the natural frequency of oscillation of the moving part of the torque motor.
  • the arrangement functions as a phasesensitive detector giving no displacement from the-central position when the supplies are exactly out of phase, and a maximum displacement in one sense or the other when the supplies are in phase or exactly out of phase. If such an arrangement is supplied with direct current in both windings, it will function as an analogue multiplying device, the displacement or force being pr'oportionalto both the current in 'the magnetising winding of the cores and the current through the actuating winding on the bobbin.
  • FIG. 1 is a longitudinal section through a transducer according to the present invention designed to function as a linear force motor
  • FIG. 2 is a transverse section of the transducer of FIG. 1,
  • FIG. 3 is a diagrammatic view of the pole pieces, and their connecting yokes employed in the transducer of FIGS. 1 and 2, and
  • FIG. 4 is a diagrammatic view of the pole pieces and their magnetising cores in an alternative embodiment of the invention.
  • the body of the transducer consists of a housing, of which only the end plates, l and 2, appear in the Figures. These end plates support the armature 3 of the transducer, which is in the form of a soft iron bobbin, the bobbin being carried at each end by a flexible diaphragm 4, 5 mounted in an aperture in the end plates.
  • armature 3 Through the centre of the armature 3 is a rod 6 of non-magnetic steel which constituts the output shaft of the transducer, which is arranged to function as a linear force motor, and is provided with means, (not shown) for attachment to the spool of a hydraulic spool valve or other equipment with which the force motor is to be used.
  • the bobbin 3 includes end cheeks 3a, 3b carries an actuating winding 7 connected to the input terminals ofthe motor (not shown).
  • each end of the transducer are a pair of soft iron plates 8, 9, and 10, 11, which form pole pieces and establish the magnetic gaps in which the end cheeks of the bobbin-shaped armature are free to move.
  • the outermost two, 8, l l are of the one polarity and the innermost two, 9, 10, are of the opposite polarity.
  • the plates 8 and 9, and also theplates l0, and l I, are spaced apart by a distance which is very slightly less than the thickness of the end checks of the armature, and the apertures in the plates are slightly larger than the end cheeks, so that the armature can move freely without risk of touching them.
  • the outermost pair of pole pieces 8 and 11 are coupled together by a pair of soft iron yokes 14, 15 of triangular section, and the innermost pair by a pair of similar yokes 12, 13. These components are shown separately, for clarity, in FIG. 3.
  • a pair of permanent magnets are employed acting on these yokes.
  • a channel-shaped magnet 16 running most of the length of the transducer is arranged to have its north pole abutting against the yoke 12 and its south pole against the yoke 15.
  • a similar magnet 17 on the other side of the motor has its north pole abutting against the yoke 13 and its south pole abutting against the yoke 14. The magnets therefore keep the yokes and the pole piece plates magnetised with the polarities shown in FIG. 1.
  • the overall length was 3 inches and the outside diameter was 2% inches
  • the armature was a bobbin of 50:50 Ni Fe with 1600 turns of 34 s.w.g. PVA self-bonding copper wire.
  • the cheeks of the armature were 0.840 inch diameter and 0.200 inch disc thickness and the magnets 16, 17 were of Alcomax 3 (Registered Trade Mark) with their edges chamfered to fit together as shown in FIG. 2.
  • the pole pieces 8, 9, 10, 11, and the yokes 12, 13, 14, 15, were of 50:50 Ni Fe.
  • FIG. 4 shows an alternative transducer according to the invention.
  • the iron components throughout are made of magnetically soft low hysteresis material so that their magnetisation, within limits set by magnetic saturation, is proportional to the current flowing through the coils.
  • the force on the bobbin is proportional to each of the currents, so that the device acts as an analogue multiplier. If the coils are fed from a common source, by connecting them in series or in parallel, the device has a square-law characteristic, and if the coils are supplied with alternating current at a frequency high compared with the natural frequency of oscillation of the moving bobbin, then the device serves as a phase detector, or a square-law AC force motor, as the case may be.
  • a moving coil transducer comprising a bobbin of magnetically soft ferro-magnetic material having a cylindrical portion wound with an actuating winding between end cheeks, each of the end cheeks being disposed in the gap between a pair of axially spaced magnetically linked pole pieces at each end comprising parallel plates having apertures shaped to admit the end cheeks and spaced apart at a distance approximately equal to the thickness of the end cheeks.
  • a moving coil transducer in which the innermost pair of pole pieces are connected by soft iron yokes, and the outermost pair are connected by soft iron yokes, and permanent magnets are arranged between the yokes of the inner pair and the yokes of the outer pair to magnetically link the pole pieces and maintain the pole pieces with the required polarities.
  • a moving coil transducer comprising a bobbin of magnetically soft ferro-magnetic material having a cylindrical portion wound with an actuating winding between end cheeks, each of the end cheeks being disposed in the gap between a pair of pole pieces comprising parallel plates having apertures shaped to admit the end cheeks and spaced apart at a distance approximately equal to the thickness of the end cheeks, said bobbin being supported with its end cheeks in the pole piece gaps by a pair of flexible diaphragrns, the spring stiffness of the diaphragms providing a restoring force to maintain the end cheeks centralised in the gaps when no current is flowing through the actuating winding.
  • a moving coil transducer having an axial rod of non-magnetic material passing centrally through the bobbin and screwed at its ends to take clamping nuts by means of which the bobbin is clamped to the diaphragms.
  • a moving coil transducer comprising a bobbin of magnetically soft ferro-magnetic material having a cylindrical portion wound with an actuating winding between end cheeks, each of the end cheeks being disposed in the gap between a pair of pole pieces comprising parallel plates having apertures shaped to admit the end cheeks and spaced apart at a distance approximately equal to the thickness of the end cheeks, the innermost pole piece at each end being coupled to the outermost pole piece at the other end by one or more soft magnetic cores carrying magnetising windings.
  • a moving coil transducer in which the actuating winding is connected in series with the magnetising windings so that in operation the force acting on the bobbin is proportional to the square of the current passing through the transducer.
  • a moving coil transducer in combination with two sources of direct current connected one to the actuating winding and the other to of the same frequency applied oneto the actuating winding, and the other to the magnetising windings, so that the force acting on the bobbin is a measure of the phase difference between the currents in the two coils.

Landscapes

  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Reciprocating, Oscillating Or Vibrating Motors (AREA)
  • Electromagnets (AREA)
US00261790A 1971-06-15 1972-06-12 Electro-mechanical transducer Expired - Lifetime US3755699A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB2802371A GB1398083A (en) 1971-06-15 1971-06-15 Electro-mechanical transducer

Publications (1)

Publication Number Publication Date
US3755699A true US3755699A (en) 1973-08-28

Family

ID=10269027

Family Applications (1)

Application Number Title Priority Date Filing Date
US00261790A Expired - Lifetime US3755699A (en) 1971-06-15 1972-06-12 Electro-mechanical transducer

Country Status (8)

Country Link
US (1) US3755699A (enrdf_load_stackoverflow)
JP (1) JPS542115B1 (enrdf_load_stackoverflow)
CA (1) CA955637A (enrdf_load_stackoverflow)
DE (1) DE2229332C3 (enrdf_load_stackoverflow)
FR (1) FR2141956B1 (enrdf_load_stackoverflow)
GB (1) GB1398083A (enrdf_load_stackoverflow)
IT (1) IT956559B (enrdf_load_stackoverflow)
SE (1) SE392372B (enrdf_load_stackoverflow)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4235153A (en) * 1978-11-02 1980-11-25 General Electric Company Linear motion, electromagnetic force motor
US4315197A (en) * 1980-02-07 1982-02-09 The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration Linear magnetic motor/generator
US4363980A (en) * 1979-06-05 1982-12-14 Polaroid Corporation Linear motor
US4631430A (en) * 1985-06-17 1986-12-23 Moog Inc. Linear force motor
US4903578A (en) * 1988-07-08 1990-02-27 Allied-Signal Inc. Electropneumatic rotary actuator having proportional fluid valving
US5587615A (en) * 1994-12-22 1996-12-24 Bolt Beranek And Newman Inc. Electromagnetic force generator
US20100060393A1 (en) * 2008-09-08 2010-03-11 Ls Industrial Systems Co., Ltd. Electromagnetic linear actuator
US20140028420A1 (en) * 2006-03-13 2014-01-30 Woodward Governor Company Moving Magnet Actuator with Counter-Cogging End-Ring and Asymmetrical Armature Stroke
US20220244077A1 (en) * 2021-01-29 2022-08-04 Sensata Technologies, Inc. Dual rotary variable differential transducer
US11837936B2 (en) * 2012-05-22 2023-12-05 Minebea Mitsumi, Inc. Vibrator generator having swing unit, frame and elastic member

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0060969B1 (de) * 1981-03-21 1985-12-18 Vacuumschmelze GmbH Magnetantriebssystem zur Erzeugung linearer Bewegungen
ATE46787T1 (de) * 1985-05-28 1989-10-15 Siemens Ag Feststellvorrichtung fuer feuerschutztueren.
US5017819A (en) * 1986-11-04 1991-05-21 North American Philips Corporation Linear magnetic spring and spring/motor combination
JPH01269722A (ja) * 1988-04-22 1989-10-27 Toshiro Higuchi 磁気制御軸受ユニット
GB8819166D0 (en) * 1988-08-12 1988-09-14 Ass Elect Ind Magnetic actuator & permanent magnet
DE19605412A1 (de) * 1996-02-14 1997-08-28 Voss Michael Dipl Ing Elektrodynamischer Gleichstromlinearmotor mit aktiver Klemmung
GB0005185D0 (en) * 2000-03-04 2000-04-26 Luk Lamellen & Kupplungsbau Gear engagement mechanisms

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR1473957A (fr) * 1965-12-24 1967-03-24 Messier Fa Moteur magnétique à courant alternatif et ses applications aux servo-mécanismes
US3351850A (en) * 1967-11-07 Electro-magnetic pickofp devices

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3351850A (en) * 1967-11-07 Electro-magnetic pickofp devices
FR1473957A (fr) * 1965-12-24 1967-03-24 Messier Fa Moteur magnétique à courant alternatif et ses applications aux servo-mécanismes

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4235153A (en) * 1978-11-02 1980-11-25 General Electric Company Linear motion, electromagnetic force motor
US4363980A (en) * 1979-06-05 1982-12-14 Polaroid Corporation Linear motor
US4315197A (en) * 1980-02-07 1982-02-09 The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration Linear magnetic motor/generator
US4631430A (en) * 1985-06-17 1986-12-23 Moog Inc. Linear force motor
US4903578A (en) * 1988-07-08 1990-02-27 Allied-Signal Inc. Electropneumatic rotary actuator having proportional fluid valving
US5587615A (en) * 1994-12-22 1996-12-24 Bolt Beranek And Newman Inc. Electromagnetic force generator
US20140028420A1 (en) * 2006-03-13 2014-01-30 Woodward Governor Company Moving Magnet Actuator with Counter-Cogging End-Ring and Asymmetrical Armature Stroke
US20100060393A1 (en) * 2008-09-08 2010-03-11 Ls Industrial Systems Co., Ltd. Electromagnetic linear actuator
US11837936B2 (en) * 2012-05-22 2023-12-05 Minebea Mitsumi, Inc. Vibrator generator having swing unit, frame and elastic member
US20240055964A1 (en) * 2012-05-22 2024-02-15 Minebea Mitsumi Inc. Vibrator generator having swing unit, frame and elastic member
US12095330B2 (en) * 2012-05-22 2024-09-17 Minebea Mitsumi Inc. Vibrator generator having swing unit, frame and elastic member
US20220244077A1 (en) * 2021-01-29 2022-08-04 Sensata Technologies, Inc. Dual rotary variable differential transducer
US12320676B2 (en) * 2021-01-29 2025-06-03 Sensata Technologies, Inc. Dual rotary variable differential transducer

Also Published As

Publication number Publication date
DE2229332A1 (de) 1973-01-11
SE392372B (sv) 1977-03-21
JPS542115B1 (enrdf_load_stackoverflow) 1979-02-02
FR2141956A1 (enrdf_load_stackoverflow) 1973-01-26
DE2229332C3 (de) 1980-11-06
CA955637A (en) 1974-10-01
IT956559B (it) 1973-10-10
GB1398083A (en) 1975-06-18
FR2141956B1 (enrdf_load_stackoverflow) 1977-12-23
DE2229332B2 (de) 1980-03-13

Similar Documents

Publication Publication Date Title
US3755699A (en) Electro-mechanical transducer
US3119940A (en) Magnetomotive actuators of the rectilinear output type
US3504320A (en) Linearly acting current force transducer
US3146038A (en) Three-axis magnetic suspension
US2833968A (en) Magnetic actuator
US2810037A (en) Sensitive relay
US1764658A (en) Rotary magnet
US2769103A (en) Electromagnetic vibrator
US3518463A (en) Low inertia high thrust vibrator
JPS55106074A (en) Moving-coil type linear motor
US2708737A (en) Instrument damping system
US3775684A (en) Accelerometer
US2859391A (en) Force motor
US2587983A (en) Electromagnetic device operable by alternating current
US2951569A (en) Electromagnetic clutch
US2508380A (en) Moving coil electrical measuring
US2408641A (en) Dynamoelectric machine
US3076920A (en) Torque motors
US3278873A (en) Ultra sensitive torque motors
US3047777A (en) High-performance electromagnetic transducer
GB1008735A (en) Improvements relating to electrical devices for producing a controlled and reversibleforce or movement in a linear direction
US2942163A (en) Constant-impedance alternating current relay motor-devices
US3281772A (en) Low frequency electromagnetic hydrophone
US2928028A (en) Polarized magnet arrangement
GB1227087A (enrdf_load_stackoverflow)

Legal Events

Date Code Title Description
AS Assignment

Owner name: VICKERS, INCORPORATED, MICHIGAN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:SPERRY LIMITED;REEL/FRAME:004548/0147

Effective date: 19860303

Owner name: VICKERS, INCORPORATED, 1401 CROOKS ROAD, TROY, MI.

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:SPERRY LIMITED;REEL/FRAME:004548/0147

Effective date: 19860303