US3694784A - Laminated magnetic core for induction devices and laminations for forming such magnetic core - Google Patents

Laminated magnetic core for induction devices and laminations for forming such magnetic core Download PDF

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Publication number
US3694784A
US3694784A US212454A US3694784DA US3694784A US 3694784 A US3694784 A US 3694784A US 212454 A US212454 A US 212454A US 3694784D A US3694784D A US 3694784DA US 3694784 A US3694784 A US 3694784A
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United States
Prior art keywords
yoke
yoke leg
leg sections
width
central web
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
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US212454A
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English (en)
Inventor
Ernst Meili
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.)
F Knobel Elektro Apparatebau AG
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F Knobel Elektro Apparatebau AG
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Application filed by F Knobel Elektro Apparatebau AG filed Critical F Knobel Elektro Apparatebau AG
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F38/00—Adaptations of transformers or inductances for specific applications or functions
    • H01F38/08—High-leakage transformers or inductances
    • H01F38/10—Ballasts, e.g. for discharge lamps
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/24—Magnetic cores
    • H01F27/245—Magnetic cores made from sheets, e.g. grain-oriented
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
    • H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
    • H01F41/0206—Manufacturing of magnetic cores by mechanical means
    • H01F41/0233—Manufacturing of magnetic circuits made from sheets

Definitions

  • ABSTRACT A laminated magnetic core for electric induction devices comprising a shell formed of laminations.
  • Each of said laminations comprising two parallel yoke legs and two outer legs arranged between and perpendicular to such parallel yoke legs.
  • a central leg is disposed parallel to the outer legs and forms with one of said parallel yoke legs an air gap.
  • Each of the laminations of the shell embodying similar U-shaped lamination elements comprising a respective outer leg and unequal length yoke leg sections protruding from the ends of such respective outer legs.
  • These lamination elements bear against one another at the end faces of their longer yoke leg sections to form a shell lamination for the magnetic core. Further, such lamination elements bear at the end faces of their shorter yoke leg sections against a central web forming the central leg and arranged between such shorter yoke leg sections.
  • the present invention broadly relates to improvements in laminated magnetic cores for electric induction devices and also pertains to new and improved punched magnetic core laminations for such cores, such magnetic core comprising a shell formed of two yoke legs which are parallel to one another, two outer legs disposed between and extending perpendicular to such parallel yoke legs and a central leg which is parallelto the outer legs, which central leg together with one of the yoke legs forms an air gap.
  • Laminated shell cores for electric induction devices are known to the art which possess an E-shaped component with equal length legs which are interconnected with one another through the agency of an I-shaped portion serving as a yoke.
  • the individual laminations of such laminated magnetic core are stamped-out of a sheet metal member without waste by means of the socalled DIN-cut, wherein in each case two E-shaped portions having their legs abutting one another at their ends are simultaneously stamped-out and from the windows formed by the abutting legs there arestamped-out two I-shaped portions.
  • Another objective of this invention is to provide a laminated magnetic core, the air gap between the central or middle leg and one yoke leg of which can be varied and the laminations of which additionally can be stamped-out from sheet metal without waste.
  • the laminated magnet core of the present invention is manifested by the features that shell possesses similar U-shaped shell or lamination elements formed from a respective outer leg and unequal length yoke leg sections or portions shorter yoke leg sections and embodying the central leg.
  • Pat. No. 3,201,731 teaches to the art forming the laminations from U-shaped shell portions with different length legs by punching such out from a strip of constant width, wherein, in each case, two laminations which mutually interengage with one another with their shorter legs between the legs of the other lamination so as to form a gapless rectangle are conjointly punchedout.
  • a shell core as illustrated in the previously mentioned United States Patent and formed of such type punched-out laminations and in contrast to the inventive magnet core, it is necessary that four such laminations be assembled together in order to form a shell core cross-section. Additionally, such shell core does not possess at its central leg any adjustable air gap.
  • FIG. 1 is a plan view of a first embodiment of magnetic core for electric induction devices formed of sheet metal laminations constructed according to the teachings of the present invention
  • FIG. la and 1b illustrate the punching cuts used for fabricating the sheet metal laminations for the magnetic core of FIG. 1;
  • FIG. 2 is a plan view of a second embodiment of magnet core for an electric induction device formed of sheet metal laminations.
  • FIGS. 2a and 2b illustrate the punching cuts used for fabricating the sheet metal laminations for producing the magnetic core of FIG. 2.
  • each of the laminated magnet cores 50 (FIG. 1) and 60 (FIG. 2) as illustrated in the drawings will be seen to respectively embody a central or middle leg 13 and 23 and a respective shell 51 and 61 surrounding such legs consisting of two outer legs 11a, 12a and 21a, 22a respectively and two yoke legs 11b, 12b and 110, 12c and 21b, 22b and 21c, 220 respectively and forming the magnetic short-circuit path.
  • the cross-section of the relevant central leg is essentially twice as large as that of the shell, since the total magnetic flux in the central leg is subdivided in such a manner that only one half of the flux flows through the shell. Consequently, with constant thickness of the magnetic core the central leg can be twice as wide as the jacket.
  • -ment 11 and 12 comprises a respective outer leg 11a and 12a and two yoke leg portions or sections 11b, 11c and 12b, 120 respectively, extending perpendicular to the associated outer leg 11a and 12a respectively and protruding from the ends of such outer legs, as shown.
  • Both of the lamination elements 11 and 12 abut against one another at the free ends of their longer yoke leg sections 11b and 12b.
  • a central web 13 which is disposed parallel to the outer legs 11a and 12a, this central web 13 embodying the central leg and simultaneously filling-out the intermediate compartment or space formed at the lamination and which is located between the shorter yoke leg sections 1 1c and 120.
  • a respective window opening 14 is formed between the central web or leg 13 and each of the outer legs 11a and 12a, as shown.
  • the central web 13 can be displaceably 'guidedin its lengthwise direction by means of the shorter yoke leg sections 1 1c and 120.
  • the dimensions of the laminated magnet core 50 are chosen in such a manner that the laminations thereof can be fabricated by means of a punching or stampingcut to be described more fully in conjunction with the showing thereof depicted in FIGS. la and 1b.
  • a lamination width of dimension a and a central web width of 2a there is obtained a magnet core having the outside dimensions 40 to 6a and with window opening openings 14, the height of which amounts to 24 and the width of which amounts to a.
  • the length of the shorter yoke leg sections 116 and 120 amounts to 2a and is smaller by the amount a than the length of the longer yoke leg sections 1 lb and 12b.
  • the individual rectangles can be lined up adjacent one another into a strip of constant width, possessing the dimension 5a in FIG. la and the dimension 4a in FIG. lb.
  • the individual sheet metal laminations of the laminated magnetic core importantly can be punched-out of such sheet metal strips 15 without waste when there is provided the rectangular arrangements depicted in FIGS. la and 1b.
  • the lamination elements 21 and 22 which abut one another by means of the free ends of both of their longer yoke leg sections or portions 21b and 22b form a lamination 61 which possesses an intermediate space between the shorter yoke leg sections 210 and 22b, as shown.
  • This intermediate space is filled by a central or middle web 23 which is disposed parallel to the outer legs 21a and 22a and embodies the central leg.
  • This central web 23 similar to the central web 13 of FIG. 1, can be displaced in its lengthwise direction, so that there is obtained an adjustment of the air gap 26 at the central or middle leg.
  • window openings 24 Between the central leg 23 and outer legs 21a and 22a there are formed window openings 24.
  • this magnet core With a lamination width of dimension a and a central web width of 2a this magnet core possesses a height of the window openings 24 of a.
  • the width b of this window opening 24, on the otherhand, can be freely selected.
  • the shorter yoke leg sections 210 and 220 are shorter by the amount a than the longer yoke leg sections 21b and 22b respectively. It is thus possible to form magnetic cores which possess outside dimensions of 3a and 4a 2b.
  • FIGS. 2a and 2b there is illustrated the manner in which two respective lamellae of the lamination 'elements 21 and 22 can be interleaved or interfitted in pairs with one another.
  • the respective shorter yoke leg sections 210 or 220 of the one lamination element 21 or 22 always engages between the yoke leg sections 220, 22b or 21b, 210 of the other jacket element and fills the space forming the window openings 24.
  • Each two lamellae of the lamination elements 21 and 22 form a gapless rectangle with the sides having the dimensions 4a and 2a b.
  • the lamellae of the lamination or shell elements 21 and 22 can be punched-out in the form of such abutting rectangles from a strip 25 of constant width, possessing the dimension 2a b (FIG. 2a) and the dimension 4a (FIG. 2b).
  • the central webs or legs 23, which possesses a square cross-section with a side length dimension of 2a, are likewise punched-out free of waste from a second sheet metal strip (not illustrated) having a width possessing the dimension 2a.
  • the respective air gap 16 or 26 at the relevant central web or leg 13 or 23 can be easily adjusted without having to tolerate any undesired air gap at the lamination 51 or 61 respectively.
  • the described magnetic cores 50 and are preferably used for inductance or choke coils for the operation of fluorescent tubes. In so doing, it is important to dimension the magnet core in such a fashion that without economical or technological drawbacks there is obtained a low constructional height of the series connected devices.
  • the magnetic core of FIG. 1 owing to its cross-sectional dimensions of 4a and 6a is particularly suitable for series connected devices.
  • the height of this magnetic core in relation to its width is in a ratio of 1:1.5, rendering possible the economical construction of series connected devices of low structural height, whereby material can be saved at the socket of the fluorescent tubes, also bringing with it advantages as concerns lighting technology and aesthetic effect.
  • the magnetic cores are arranged in a housing formed of sheet iron, then, in certain cases it is desired to incorporate such iron sheet metal housing as active component in the magnetic circuit.
  • the lamination elements are reduced in their width by an amount corresponding to the thickness of the sheet iron used for the housing, so that the width thereof is a little smaller than half the width of the central web.
  • a laminated magnetic core for induction devices comprising a shell formed of laminations and possessing two yoke legs parallel to one another and two outer legs arranged between and perpendicular to said parallel yoke legs, a central leg disposed parallel to said outer legs and forming with one of said parallel yoke legs an air gap, each of said laminations embodying similar substantially U-shaped lamination elements comprising a respective outer leg and unequal length yoke leg sections protruding from the ends of said respective outer legs, said lamination elements bearing against one another at the end faces of their longer yoke leg sections to define one of said parallel yoke legs with the remaining shorter yoke leg sections defining the'other parallel yoke leg, and a central web embodying said central leg arranged between said shorter yoke leg sections, said lamination elements bearing at the end faces of their shorter yoke leg sections against said central web disposed between said shorter yoke leg sections.
  • a lamination'for the magnetic core of electric induction devices comprising similar substantially U- shaped lamination elements each possessing a respective outer leg and unequal length yoke leg sections protruding from the ends of its associated respective outer leg, said lamination elements bearing against one another at the end faces of their longer yoke leg sections to define one parallel yoke leg with the remaining shorter yoke leg sections defining another parallel yoke leg, and a central web arranged between said shorter yoke leg sections, said lamination elements hearing at the end faces of their shorter yoke leg sections against said central web.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Manufacturing Cores, Coils, And Magnets (AREA)
  • Harvester Elements (AREA)
US212454A 1970-12-28 1971-12-27 Laminated magnetic core for induction devices and laminations for forming such magnetic core Expired - Lifetime US3694784A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CH1923170A CH536545A (de) 1970-12-28 1970-12-28 Lamellierter Magnetkern für Induktionsgeräte

Publications (1)

Publication Number Publication Date
US3694784A true US3694784A (en) 1972-09-26

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Family Applications (1)

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US212454A Expired - Lifetime US3694784A (en) 1970-12-28 1971-12-27 Laminated magnetic core for induction devices and laminations for forming such magnetic core

Country Status (13)

Country Link
US (1) US3694784A (fr)
AT (1) AT311486B (fr)
BE (1) BE777083A (fr)
CA (1) CA939765A (fr)
CH (1) CH536545A (fr)
ES (1) ES398127A1 (fr)
FR (1) FR2120827A5 (fr)
GB (1) GB1338769A (fr)
IL (1) IL38409A (fr)
IT (1) IT945686B (fr)
NL (1) NL7117580A (fr)
NO (1) NO133116C (fr)
SE (1) SE369002B (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6865057B2 (en) * 1999-10-05 2005-03-08 Seagate Technology Llc Gapless longitudinal magnetic recording head with flux cavity
US6865056B1 (en) 1999-10-05 2005-03-08 Seagate Technology Llc Longitudinal magnetic recording heads with variable-length gaps
US20060114095A1 (en) * 2004-11-26 2006-06-01 Jung Fong Electronics Co., Ltd. Electric component and its manufacturing material

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2950789C2 (de) * 1979-12-17 1982-07-01 May & Christe Gmbh, Transformatorenwerke, 6370 Oberursel Vorschaltgerät für Leuchtstofflampen
EP0580131B1 (fr) * 1992-07-20 1995-11-08 Knobel Ag Lichttechnische Komponenten Procédé de fabrication d'une réactance ou d'un transformateur avec des tôles de noyau en forme de E constituées de deux tôles en forme de U

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB803914A (en) * 1955-04-20 1958-11-05 Bernhard Philberth Stationary electromagnetic induction apparatus
US3201731A (en) * 1962-11-27 1965-08-17 Electro Netic Steel Inc Transformer core and lamination therefor

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB803914A (en) * 1955-04-20 1958-11-05 Bernhard Philberth Stationary electromagnetic induction apparatus
US3201731A (en) * 1962-11-27 1965-08-17 Electro Netic Steel Inc Transformer core and lamination therefor

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6865057B2 (en) * 1999-10-05 2005-03-08 Seagate Technology Llc Gapless longitudinal magnetic recording head with flux cavity
US6865056B1 (en) 1999-10-05 2005-03-08 Seagate Technology Llc Longitudinal magnetic recording heads with variable-length gaps
US20060114095A1 (en) * 2004-11-26 2006-06-01 Jung Fong Electronics Co., Ltd. Electric component and its manufacturing material

Also Published As

Publication number Publication date
IT945686B (it) 1973-05-10
NO133116B (fr) 1975-12-01
CH536545A (de) 1973-04-30
AT311486B (de) 1973-11-26
DE2162543A1 (de) 1972-07-27
SE369002B (fr) 1974-07-29
NL7117580A (fr) 1972-06-30
IL38409A0 (en) 1972-02-29
FR2120827A5 (fr) 1972-08-18
NO133116C (fr) 1976-03-10
GB1338769A (en) 1973-11-28
IL38409A (en) 1974-06-30
DE2162543B2 (de) 1976-01-15
BE777083A (fr) 1972-04-17
CA939765A (en) 1974-01-08
ES398127A1 (es) 1974-07-16

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