US2607814A - Magnetostrictive four-pole - Google Patents

Magnetostrictive four-pole Download PDF

Info

Publication number
US2607814A
US2607814A US242111A US24211151A US2607814A US 2607814 A US2607814 A US 2607814A US 242111 A US242111 A US 242111A US 24211151 A US24211151 A US 24211151A US 2607814 A US2607814 A US 2607814A
Authority
US
United States
Prior art keywords
bar
disc
magnetostrictive
frequency
bolts
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
US242111A
Other languages
English (en)
Inventor
Bloch Heinz
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.)
Patelhold Patenverwertungs and Elektro-Holding AG
Original Assignee
Patelhold Patenverwertungs and Elektro-Holding AG
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 Patelhold Patenverwertungs and Elektro-Holding AG filed Critical Patelhold Patenverwertungs and Elektro-Holding AG
Application granted granted Critical
Publication of US2607814A publication Critical patent/US2607814A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic elements; Electromechanical resonators
    • H03H9/46—Filters
    • H03H9/62—Filters comprising resonators of magnetostrictive material

Definitions

  • the present invention relates to magnetostrictive devices and in particular to those of the type comprising a bar made from magnetostrictive material mounted at a vibration node and longitudinally oscillating, the bar being supported intermediate its ends by a bearing and a coil surrounding the bar on each side of the bearing.
  • the bar is premagnetized by one or more permanent magnets and the terminal ends of the two coils (four in number) Vform what is commonly known as a .four-pole.
  • Such four-poles have various uses such for example as wave filters or as frequency stabilizers, and are described in ldetail in various patents'such as Swiss Patent No. 197,694 and United States Patent No. 1,750,124.
  • the mounting of the bar causes dfliculties because two contradictory requirements must be met.
  • the'bar mounting should allow the bar full freedom of movement in the longitudinal direction, also for Vmounting at a node, this being necessary in consideration of the practically never perfect immobility ofthe node in the bar.
  • the bar must be secured crosswise to the longitudinalv axis as xedly as possible in order that existing air gaps between the magnetostrictive bar and the one or more premagnetizing permanent magnets and also any air gaps provided in the flux return Yokes will remain unchanged while the bar is oscillating.
  • the coils energizing the' bar shouldbe capable of being Awound vas close to the bar as possible without touching the same, and this again requires an accurate and laterally fixed mounting of the bar.
  • the entire four-pole should form a structural unit which as a whole iseasily exchangeable and is sturdy enough to be capable of being used in portable equipment.
  • the two extreme requirements concerning the mounting of the bar can be fulfilled according to the present invention by providing a circular disc on the bar at the node where it is to be mounted and clamping the disc itself at its rim portion to al support.
  • the bar is thereby mounted crosswise to the longitudinal axis with suicient resistance to lateral displacements.
  • the disc should beV proportioned with respect to thickness' and diameter ina manner such that one of its inherent frequencies coincides with the inherent frequency of the bar with which the bar is magnetostrictively energized.
  • the bar may be allowed .to Aoperate, in its fundamental frequency (one'node in the center of the bar),
  • the disc dimensioning the disc in such awayv that also the fundamental frequency of the disc coincides with the fundamental frequency of the bar.
  • a working frequency for the disc there may be selected for example the frequency of its third harmonic and asfa working frequencxT for the bar for example the frequency of its fth harmonic, and it is thenl merely necessary to fulfill the condition that the workingv frequencies of the disc and bar coincide.
  • a circular disc whose working frequency in the case of rigid insertion of the disc rim corresponds to the working frequency of the longitudinally oscillating bar, serves as a bearing for the oscillating bar, in that this bearing disc is provided in the center of the bar concentrically thereon, and that there are connected with the rim portion of the bearing disc three non-magnetizable bolts which extend on both sides of the bearing disc parallel with the oscillating bar, in such a way that the centers of the three bolts form the edges of a prism having the cross section of an equilateral triangle, the longitudina1 axis of the prism and of the oscillating bar coinciding, and that at the free ends of the three bolts there is provided on both sides of the bearing disc and parallel with this disc an end plate for each, there being installedbetween each end plate and the bearing disc one of the said coils concentrically withthe oscillating bar and there being inserted on both sides of the bearing disc at least
  • Fig. 1 isa Vertical central section taken on line l-I of Fig. 2 showing a construction adapted particularly for use with frequencies below 50 kilocycles;
  • ⁇ lFig. 2 is a horizontal section on line 2 24 of Fig. 1; I
  • Fig. 6 is a vertical View partly in section illustrating another modified construction.
  • the magnetostrictive four-pole is seen to be comprised of a straight cylindrical bar I of magnetostrictive material, the composition of which is discussed hereinafter.
  • a circular bearing disc 2 of magnetizable material Intermediate the ends of bar I and around the same is positioned a circular bearing disc 2 of magnetizable material, the bar and disc being concentric, and the central hole in the disc through which the bar passesv being of substantially the sameA diameter as the bar to provide a tight press t therebetween.
  • Three bolts 3 of a non-magnetizable material such as for example brass, are rigidly connected with the rim portion of disc 2 which, is preferably reinforced by annular discs 4, 4' applied to opposite faces thereof and held in position by the bolts 3 each of which as illustrated is divided into two halves secured together with the reinforcing discs 4, 4'- and disc 2 secured therebetween.
  • the upper and lower ends of the three bolts 3 terminate in threaded sections; I4secured by nuts I4 to end plates '5, and they latter are provided I with axiall apertures through which the bar I passes;
  • Theg apertures inthe plates 5 are preferablyV of substantially the same diameter as that of bar I so as to; provide a pathy of loW reluctance for the magneticv flux produced in the bar I to passl into, ⁇ the plates 5.
  • V two coils 6- are utilized for energizing barV I magnetically.
  • Each, ⁇ coil is carriedV on a spool 7 arrangedconcentrically on the bar and one of the; coils is arranged below andthe other above the centrally located disc 2:.
  • the magnet bars 8., Bf have their outer ends secured to plates 5 by screws 9 ,L are arranged coaxially and parallelwith the bar I of magnetostrictive material, and are disposed in any one of the three-spaces between any two. adjacent bolts 3. In the two ⁇ remaining spaces between the bolts 3f, are arranged cylindrical bars I 0 of .magnetizable material.
  • Bars I0 which extend parallel to ⁇ bars I and 8, 8 are secured rigidly at their inner ends to the reinforcing discs 4, 4 and their outer ends terminate short of the end plates 5 to establish air gaps I2 the lengths of which can be made adjustable by screws II axially aligned With the bars I0 and which thread through the plates 5.
  • the bars I0 and screws II thus constitute a shunt yoke for regulation of the premagnetization of bar I from the permanent magnets 8, t.
  • a second set of permanent magnet bars 8, 8 may be used in place of Vone of the sets of magnetizable bars I0.
  • the component assembly as described is preferably enclosed by a cup-shaped casing I3 to make it dust proof.
  • the casing being divided axially into two halves which t into a centrally located ring I5.
  • the threadedl ends I4 of bolts3 extend through the end walls of thecasing halves and areV anchored there by nuts I4" which when tightened press the halves of the casingtowards each other into the ring I 5.
  • Ring I 5 also serves to support the connecting terminals I6 for the coils 6.
  • Thefrequency fo corresponds to the frequency to which both the bar I and bearing disc 2 are tuned, theworking frequency corresponding in the present example to the frequency of fundamental vibration both of bar I and disc 2.
  • the Q factor of the fourpole can be determined according to the equation for asv a result; of the AE l effect. discussed below, all ⁇ curvesbeing plotted" asza function ofthe change. in premagnetization field strength H.
  • the. four pole presents different. properties.
  • zoneI. up. to the broken vertical boundary line of premag.- netization. field'l strength value H
  • the Q factor and the factor is relatively-high, thevoltage Uisrelatively low, y
  • Y 5f i f o is relatively high.
  • the disc 2P andi 'bar I5 possess av certain-l ⁇ working frequency, means must: be provided totune 'thefinishedfour* ⁇ poleY accurately to a desiredl'rtheoretical frequency; For thispurpose the propertyof' ferro-magnetic materials; known; as ⁇ AE effect/jean be utilized; The modulus of elasticity asafunetionofthepremagnetization is; in fact', not ⁇ a constant; andL therefore, by Varying, 'the premagnetization ofbar Isthemoduluspfrelasticity;thereofandhence its inherent c natural: frequency: of?- vibration1 canL be.
  • Thepr'emag-L netization from .magnets 8; 8 ⁇ can.v be varidf byv 5 an air gap in the circuit of the premagnetization flux.
  • the premagnetization of the magnetic circuit by the permanent magnets can be made adjustable by providing an adjustable air gap between one end of the magnet 8a. and an adjustable screw I3a threaded into the end plate 5a, as shown in Fig. 6, the opposite end of magnet 8a, being secured to the annular disc 4a.
  • two, or three permanent magnets can be installed in the arrangement on each side of the bearingdisk between the bolts 3 as previously explained.
  • the bar I must not shift crosswise to its longitudinal axis, as this may easily cause distunbances in the vibration as soon as the bar touches the spools 1 or the end plates anywhere. If one selects for the disc 2 a material whose coefcient of expansion is smaller than that of the material of the bar I (e. g. Invar, an alloy of 36% Ni and 64% Fe) and if one presses the disc onto the bar at a temperature below the mean operating temperature, one obtains at the operating temperature an insertion which is sufficiently rigid and stable to prevent cross dis-placements of the bar I.
  • a material whose coefcient of expansion is smaller than that of the material of the bar I (e. g. Invar, an alloy of 36% Ni and 64% Fe)
  • the embodiment of the invention shown in Figs. 1 and 2 can be used for frequencies in the range below 50 kilocycles. For frequencies between 50 and 500 kilocycles the embodiment according to Fig, 5 is especially suitable. In accordance with the higher working frequencies and the consequent shorter dimensions of the bar I', also the bearing disc 2 should be proportionally thinner. In order to be able to make the .edge of this disc rigid nevertheless, it is advisable to provide the disc not with the clamping discs 4 shown in Fig. 1, but rather with a thickened rim 42a. In this rim the bolts 3 may be fastened and formed as in Fig. 1. However, a construction as per Fig. 5 may also be used, consisting of an inner bolt 20 with sleeves 2
  • a ⁇ set screw 22 is provided in a central bore in the upper and lower end plates 5 whose axis points in the direction of the longitudinal axis of the oscillating bar I and is separated from the end face thereof by the air g-ap 23.
  • This arrangement has two advantages. First, the space between each end fplate 5' and disc 2' can be made suiciently long to install the coil body (not shown) even if the bar I is short (that is, if the frequencies are high).
  • the set screws 22 permit a fine regulation o- 6 of the inherent natural frequency of the bar I' even whenit is desired to press the permanent magnets 8" and bars I0' simply :between the end plates 5' and the disc 2', omitting the set screws 9andIIofFig.1.
  • a casing I3 is shown (partially broken away) which is pressed in a base plate ⁇ 24 so as to be dust-proof, this base plate supporting at the same time the four connection terminals 25 for the coils, thus being designed ⁇ like the multi-pronged base of a conventional vacuum. tube.
  • the fundamental frequency of the plate 2 can Vbe tuned on the frequency of a harmonic (for instance the third or the fifth), this being advisable when it is desired to work with such high frequencies that a bar working at the fundamental frequency would be too short to be handled conveniently.
  • a harmonic for instance the third or the fifth
  • a magnetostrictive four-pole comprising a bar of magnetostrictive material, a circular bearmg disc of magnetizable material mounted concentrically upon and rigidly connected with said bar intermediate the bar ends, the Working frequency of said mounted disc corresponding to the working frequency of the longitudinally oscillatable bar, three bolts of non-magnetizable material extending from the rim portion of said disc in opposite directions parallel with said bar, said bolts being so spaced about the axis of said disc as to form the edges of a prism having the cross section of an equilateral triangle and whose axis coincides with the axis of said bar, end plates of magnetic material parallel with said bearing disc and secured to the opposite ends of said three bolts, cylindrical coils concentric with and surrounding said bar respectively between said bearing disc and said end plates, a permanent bar magnet arranged longitudinally of said magnetostrictive bar between said bearing disc and each of said end plates in one of the three spaces between each pair of said bolts, and at least one bar of magnetizable material arranged longitudinally
  • said three bolts each are continuous between said end plates passing through apertures in saidbearing disc and-which further include. afsleeve surrounding each boltk between. thebearing disc andend ⁇ plates, saidlbearing disc beingclamped. between the two sleeves. of each bolt.
  • A. magneto'strictive device as. defined in claim 1 wherein. the ⁇ endsof. said. magnetostrictive bar. terminateY s'hortfofQsaid. endy plates and whereineach said end plate is provided withl an axially disposedserew adjustable longitudinally and confronting ⁇ - thefend faces ofv said magnetizable bar toesta-bli'slfrr an adjustable. air gap therebetween.
  • a magnetostrictive device as deiined in claiml and whichffu'rtherv includes a cup-shaped.

Landscapes

  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • General Electrical Machinery Utilizing Piezoelectricity, Electrostriction Or Magnetostriction (AREA)
  • Reciprocating Pumps (AREA)
  • Electromagnets (AREA)
US242111A 1950-08-22 1951-08-16 Magnetostrictive four-pole Expired - Lifetime US2607814A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CH691841X 1950-08-22

Publications (1)

Publication Number Publication Date
US2607814A true US2607814A (en) 1952-08-19

Family

ID=4529297

Family Applications (1)

Application Number Title Priority Date Filing Date
US242111A Expired - Lifetime US2607814A (en) 1950-08-22 1951-08-16 Magnetostrictive four-pole

Country Status (6)

Country Link
US (1) US2607814A (cs)
CH (1) CH282865A (cs)
DE (1) DE896397C (cs)
FR (1) FR1048436A (cs)
GB (1) GB691841A (cs)
NL (2) NL156647B (cs)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2720599A (en) * 1953-06-15 1955-10-11 Patelhold Patentverwertung Magnetostrictive oscillator
US2928057A (en) * 1957-01-14 1960-03-08 Itt Electromechanical filter arrangement
US3044028A (en) * 1958-04-23 1962-07-10 Harris Transducer Corp Magnetic circuit element transducer
US3113287A (en) * 1956-03-29 1963-12-03 Raytheon Co Electroacoustical transducer mounted on boat hull
US3768069A (en) * 1972-01-17 1973-10-23 Columbia Broadcasting Syst Inc Encased gradient hydrophone assembly
US4703464A (en) * 1985-05-10 1987-10-27 Raytheon Company Permanent magnet biased magnetostrictive transducer
US4901293A (en) * 1984-12-19 1990-02-13 Martin Marietta Rare earth flextensional transducer
US4907209A (en) * 1983-10-31 1990-03-06 Martin Marietta Corporation Low frequency sound transducer

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2822528A (en) * 1954-10-15 1958-02-04 Philips Corp Premagnetized inductive device

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
None *

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2720599A (en) * 1953-06-15 1955-10-11 Patelhold Patentverwertung Magnetostrictive oscillator
US3113287A (en) * 1956-03-29 1963-12-03 Raytheon Co Electroacoustical transducer mounted on boat hull
US2928057A (en) * 1957-01-14 1960-03-08 Itt Electromechanical filter arrangement
US3044028A (en) * 1958-04-23 1962-07-10 Harris Transducer Corp Magnetic circuit element transducer
US3768069A (en) * 1972-01-17 1973-10-23 Columbia Broadcasting Syst Inc Encased gradient hydrophone assembly
US4907209A (en) * 1983-10-31 1990-03-06 Martin Marietta Corporation Low frequency sound transducer
US4901293A (en) * 1984-12-19 1990-02-13 Martin Marietta Rare earth flextensional transducer
US4703464A (en) * 1985-05-10 1987-10-27 Raytheon Company Permanent magnet biased magnetostrictive transducer

Also Published As

Publication number Publication date
NL156647B (nl)
NL83437C (cs)
GB691841A (en) 1953-05-20
DE896397C (de) 1953-11-12
CH282865A (de) 1952-05-15
FR1048436A (fr) 1953-12-22

Similar Documents

Publication Publication Date Title
US2607814A (en) Magnetostrictive four-pole
US2632791A (en) Vibratory condenser converter
US2870422A (en) Accelerometer
US3146038A (en) Three-axis magnetic suspension
US2751573A (en) Apparatus for changing the resonant frequency of a seismic detector
US2245511A (en) Telephone instrument
US2318359A (en) Electromagnet
US2860313A (en) Inductive tuning device
US2628343A (en) Mechanical vibrating device
US2148523A (en) M baermann
US2696590A (en) Magnetostrictive filter device
US2740941A (en) Variable reactors
US3308647A (en) Vibration pickup with calibrating means
US3001115A (en) Linear motor system
GB1026085A (en) Improvements in or relating to circuit arrangements for production of ultrasonic oscillations
US2692344A (en) Electromechanical transducing device
US1764658A (en) Rotary magnet
US3903438A (en) Magnetic system for an oscillatory electrodynamic compressor
US2015410A (en) Vibrating system
GB1275902A (en) Nuclear magnetic resonance probe
US3020455A (en) Vibratory capacitors
US2793293A (en) Vibrating reed-type frequency standard
US2770760A (en) Mechanical vibrator
US2925538A (en) Electromagnetic device
US2353618A (en) Damping device for electrical instruments