EP0471864A1 - Elément de bobine - Google Patents

Elément de bobine Download PDF

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Publication number
EP0471864A1
EP0471864A1 EP90115820A EP90115820A EP0471864A1 EP 0471864 A1 EP0471864 A1 EP 0471864A1 EP 90115820 A EP90115820 A EP 90115820A EP 90115820 A EP90115820 A EP 90115820A EP 0471864 A1 EP0471864 A1 EP 0471864A1
Authority
EP
European Patent Office
Prior art keywords
gap
coil
magnetic
coil device
magnetic cores
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.)
Granted
Application number
EP90115820A
Other languages
German (de)
English (en)
Other versions
EP0471864B1 (fr
Inventor
Shinichiro Ito
Yukiharu Kinoshita
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.)
TDK Corp
Original Assignee
TDK Corp
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 TDK Corp filed Critical TDK Corp
Priority to EP19900115820 priority Critical patent/EP0471864B1/fr
Priority to DE1990611106 priority patent/DE69011106T2/de
Publication of EP0471864A1 publication Critical patent/EP0471864A1/fr
Priority to US07/954,428 priority patent/US5210514A/en
Application granted granted Critical
Publication of EP0471864B1 publication Critical patent/EP0471864B1/fr
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F3/00—Cores, Yokes, or armatures
    • H01F3/10—Composite arrangements of magnetic circuits
    • H01F3/14—Constrictions; Gaps, e.g. air-gaps
    • 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
    • H01F27/34—Special means for preventing or reducing unwanted electric or magnetic effects, e.g. no-load losses, reactive currents, harmonics, oscillations, leakage fields
    • H01F27/346—Preventing or reducing leakage fields

Definitions

  • the present invention relates to improvements in a coil device for use in a flyback transformer, a switching power transformer, a choke coil or the like. And more particularly, it relates to improvements in a coil device employing a magnetic core with a gap.
  • any of the conventional transformers, choke coils and so forth known heretofore it is customary to form a gap in a closed magnetic path so that the magnetic core thereof is not saturated when a desired current is caused to flow.
  • a gap (hereinafter referred simply to as gap) is formed therein to reduce the effective permeability j1. within a range of 50 to 300.
  • Another object of the present invention resides in providing an improved coil device which realizes lower production cost and enhanced reliability.
  • a coil device comprising two magnetic cores each having U-shape in section which form a closed magnetic path therein with their legs being opposed to each other and having a gap in such path, and a coil wound so as to cover the gap.
  • the feature of the present invention resides in a structure where the mutually opposed portions of the magnetic cores in the region to form the gap are so shaped that the cross-sectional area of the fore end becomes smaller than the corss-sectional area of the base end.
  • the rate of the cross-sectional area of the fore end to that of the base end is defined to be within a range of 1 to 90 percent.
  • fore end is shaped with curves defined by logarithmic functions, and a planar member is provided on the fore end, or projections are formed on the face of the fore end.
  • a coil device 1 shown in Fig. 1 comprises two sectionally U-shaped magnetic cores 2, 3 of which fore ends but to each other, wherein a gap 5 is formed between opposed faces of one-side legs 2a, 3a and a coil 4 is wound thereon.
  • FIG. 26 Some examples of such sectionally U-shaped magnetic cores are illustrated in Figs. 26 and 27.
  • a rectangular core is shaped into U, and its one-side leg is shaped to be columnar.
  • the text example of Fig. 27 is a magnetic core 33 having four legs, one of which legs is a columnar leg 33a.
  • a pair of such cores are combined with each other and a coil is wound on the columnar legs thereof, although merely a single core is illustrated in each of the above diagrams.
  • such core is composed of ferrite material.
  • Fig. 2 illustrates the shape of gap portions in magnetic cores used in a conventional coil device, wherein the shapes of mutually opposed ends 2b and 3b of the magnetic cores and the gap width thereof are so determined that the effective permeability of the magnetic core is rendered uniform in the entirety.
  • the opposed ends 2b, and 3b, of the magnetic cores in the conventional coil device of Fig. 2 are shaped to be columnar in a manner that the sectional areas thereof remain unchanged.
  • the gap has a width of 3mm.
  • opposed ends 2b 2 , 3b 2 are so shaped that the sectional areas thereof are reduced by tapered portions 2d, 3d toward opposed faces 2c, 3c, and the gap 5 is formed to have a width of 2.5mm in Fig. 3, 2.0mm in Fig. 4, and 1.8mm in Fig. 5 respectively so that the effective permeability j1. becomes uniform.
  • opposed ends 2b 3 , 3b 3 of Fig. 6 are so formed that the sectional areas thereof are reduced by stepped projections 2e, 3e; and opposed ends 2b 4 , 3b 4 of Fig. 7 are so formed that the sectional areas thereof are reduced, and a core member 5a identical in material with the magnetic cores is inserted there between while being held in a gap filler (not shown) which exerts no harmful influence on the magnetic permeability ⁇ .
  • Fig. 8 graphically represents a B-H curve obtained in a conventional coil device using magnetic cores of the shape shown in Fig. 2; and Figs. 9 through 13 graphically represent B-H curves in coil devices using magnetic cores of the shapes shown in Figs. 3 through 7, respectively.
  • the saturation magnetic flux density Bm in the conventional coil device with opposed ends of the known shape shown in Fig. 8 is 5510 Gs; whereas in the coil devices of the present invention using magnetic cores of the shapes shown in Figs. 9, 10, 11, 12 and 13, the saturation magnetic flux densities are 5480, 5400, 5200, 5330 and 5400 Gs, respectively. It is also found that the linearity in the latter is not changed, although each density thereof is slightly lower than that in Fig. 8.
  • Table 1 shown below is a list of experimental results obtained by using a tester 6 of Fig. 14 and detecting the temperatures in coil centers X, coil ends Y, cores Z and peripheries W of coil devices 1 having the opposed ends of the aforementioned shapes (under the testing conditions including a frequency of 100 kHz, a current of 0.8 A, sine wave and ambient temperature of 40 ° C ).
  • the shapes (a) through (f) correspond respectively to the shapes of magnetic cores shown in Figs. 2 through 7.
  • the shapes in the embodiments of the present invention shown in Figs. 3 through 7 are so improved that, as listed in Table 1, the temperature in the coil center X is lower by 5 to 20 ° C ;the temperature in the coil end Y is lower by 3 to 12° C the temperature in the core Z is lower by 1.5 to 10° C ; and the temperature in the periphery W is lower by 2.5 to 5.5 ° C .
  • the saturation magnetic flux density is retained at a relatively high value, and the temperatures in the individual portions are lower due to the insertion of a core member 5a which is composed of the same material as that of the magnetic core.
  • the present invention is structurally simple and ensures satisfactory linearity in the B-H curve with another advantage of preventing abnormal generation of heat that may be caused in the coil around the gap by some leakage magnetic flux.
  • a gap filler of a suitable material free from exerting any harmful influence on the magnetic permeability ⁇ may be inserted in the gap, and the gap may be formed between some other legs than the center legs.
  • Typical modifications include a curved shape shown in Fig. 15; a shape of Fig. 16 where the sectional area is reduced with curved surfaces toward the opposed end faces; a bowl-like shape shown in Fig. 17; a pointed shape shown in Fig.
  • projections 14, 14 are formed on the faces of fore ends of magnetic cores 12a, 12b as illustrated in Fig. 25, there is attainable an advantage of rendering the flux density uniform in the gap and reducing the leakage flux that interlinks with the coil.
EP19900115820 1990-08-17 1990-08-17 Elément de bobine Expired - Lifetime EP0471864B1 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
EP19900115820 EP0471864B1 (fr) 1990-08-17 1990-08-17 Elément de bobine
DE1990611106 DE69011106T2 (de) 1990-08-17 1990-08-17 Spulenelement.
US07/954,428 US5210514A (en) 1990-08-17 1992-09-30 Coil device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP19900115820 EP0471864B1 (fr) 1990-08-17 1990-08-17 Elément de bobine

Publications (2)

Publication Number Publication Date
EP0471864A1 true EP0471864A1 (fr) 1992-02-26
EP0471864B1 EP0471864B1 (fr) 1994-07-27

Family

ID=8204348

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19900115820 Expired - Lifetime EP0471864B1 (fr) 1990-08-17 1990-08-17 Elément de bobine

Country Status (2)

Country Link
EP (1) EP0471864B1 (fr)
DE (1) DE69011106T2 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0729040A1 (fr) * 1995-02-22 1996-08-28 Minnesota Mining And Manufacturing Company Marqueur à noyau de ferrite

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2203210A1 (de) * 1972-01-24 1973-08-02 Siemens Ag Transduktor
DE3123006A1 (de) * 1981-06-10 1983-01-05 Ernst Roederstein Spezialfabrik für Kondensatoren GmbH, 8300 Landshut Transformator
EP0225830A1 (fr) * 1985-12-04 1987-06-16 OREGA ELECTRONIQUE & MECANIQUE Procédé de fabrication d'un circuit magnétique à faible champ magnétique rayonné, en particulier pour un transformateur haute tension alimentant un tube cathodique

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2203210A1 (de) * 1972-01-24 1973-08-02 Siemens Ag Transduktor
DE3123006A1 (de) * 1981-06-10 1983-01-05 Ernst Roederstein Spezialfabrik für Kondensatoren GmbH, 8300 Landshut Transformator
EP0225830A1 (fr) * 1985-12-04 1987-06-16 OREGA ELECTRONIQUE & MECANIQUE Procédé de fabrication d'un circuit magnétique à faible champ magnétique rayonné, en particulier pour un transformateur haute tension alimentant un tube cathodique

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0729040A1 (fr) * 1995-02-22 1996-08-28 Minnesota Mining And Manufacturing Company Marqueur à noyau de ferrite
US5767816A (en) * 1995-02-22 1998-06-16 Minnesota Mining And Manufacturing Company Ferrite core marker

Also Published As

Publication number Publication date
EP0471864B1 (fr) 1994-07-27
DE69011106T2 (de) 1994-12-01
DE69011106D1 (de) 1994-09-01

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