EP0318613B1 - Hochspannungstransformator und Verfahren zu seiner Herstellung - Google Patents

Hochspannungstransformator und Verfahren zu seiner Herstellung Download PDF

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Publication number
EP0318613B1
EP0318613B1 EP19870117994 EP87117994A EP0318613B1 EP 0318613 B1 EP0318613 B1 EP 0318613B1 EP 19870117994 EP19870117994 EP 19870117994 EP 87117994 A EP87117994 A EP 87117994A EP 0318613 B1 EP0318613 B1 EP 0318613B1
Authority
EP
European Patent Office
Prior art keywords
coil
primary
iron core
coil case
voltage transformer
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
EP19870117994
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English (en)
French (fr)
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EP0318613A1 (de
Inventor
Tomokazu Himeji Seisakusho Umezaki
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.)
Mitsubishi Electric Corp
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Mitsubishi Electric Corp
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Publication date
Application filed by Mitsubishi Electric Corp filed Critical Mitsubishi Electric Corp
Priority to EP19870117994 priority Critical patent/EP0318613B1/de
Priority to DE19873781692 priority patent/DE3781692T2/de
Publication of EP0318613A1 publication Critical patent/EP0318613A1/de
Application granted granted Critical
Publication of EP0318613B1 publication Critical patent/EP0318613B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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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
    • H01F38/12—Ignition, e.g. for IC engines

Definitions

  • This invention relates to a high-voltage transformer according to the preamble of claim 1 and a method for making the same.
  • Such a transformer is known from the Abstract of JP-A-61 231 708, and will be explained in more detail with reference to the Figs. 1 to 3.
  • Fig. 1 is a plan view showing the said conventional high-voltage transformer for internal combustion engines
  • Fig. 2 is a cross sectional view taken along line II-II of Fig. 1.
  • the high-voltage transformer 1 in the form of an ignition coil illustrated comprises a generally cylindrical coil case 2 formed of a synthetic resin, a primary coil 3 in the coil case 2, a secondary coil 4 disposed in the coil case 2 so as to surround the primary coil 3, a cylindrical sleeve 5 disposed in and fixedly mounted on the coil case 2 substantially at the center thereof for receiving an unillustrated rotary shaft of a distributor, and an iron core 6 disposed in the coil case 2 around the sleeve 5 so as to surround the primary coil 3 and the secondary coil 4.
  • the iron core 6 comprises an annular inner or central leg portion 601 disposed around the cylindrical sleeve 5 and radially inside the primary coil 3, four planar outer leg portions 602 disposed radially outside the secondary coil 4, a pair consisting of a first (or lower) and second (or upper) cross-shaped arm portions 603 and 604 interconnecting the inner and outer leg portions 601 and 602 for forming a substantially closed magnetic path which passes through the primary and secondary coils 3, 4 when these coils are energized.
  • the annular inner leg portion 601 is in contact at its opposite ends with the inner surfaces of the lower and upper arm portions 603, 604.
  • the outer leg portions 602 are slightly shorter than the inner leg portion 601 so that they are in contact at their lower end with the cross-shaped lower arm portion 603 but spaced from the upper arm portion 604 with a limited gap 605 formed therebetween.
  • a resin 7 is filled into the coil case 2 and impregnated into the spaces between the coils 3, 4 and the iron core 6 for electrically insulating the coils 3, 4 and the iron core 6 from each other as well as for firmly securing or bonding them to the coil case 2.
  • the lower arm portion 603 of the iron core 6 is moulded integrally with or otherwise firmly connected with the coil case 2, and it is exposed to the outside of the coil case 2 for dissipating heat which is generated during moulding of the coil case 2.
  • the above-described conventional high-voltage transformer 1 is produced in the following manner. First, the lower cross-shaped arm portion 603 of the iron core 6 is disposed in and integrally moulded or otherwise firmly connected with the coil case 2, and then the annular inner leg portion 601, the primary coil 3, the secondary coil 4 and the outer leg portions 602 are disposed in the coil case 2. Thereafter, the upper arm portion 604 of the iron core 6 is placed on the inner and outer leg portions 601, 602, and the resin 7 in a molten state is filled into the coil case 2 up to a pedetermined level, impregnated into the spaces between the above members and solidified to firmly install these members in the coil case 2. In this manner, the resin 7 thus impregnated serves not only for securing the members to the coil case 2 but also for improving the electrical insulation therebetween.
  • the conventional high-voltage transformer 1 as constructed above operates as follows. As shown by an electric circuit in Fig. 3, current supplied from a battery 10 to the primary coil 3 is interrupted by an electronic circuit device 11 at an appropriate timing so that a high voltage is produced at the secondary coil 4 for sparking an ignition plug (not shown).
  • the iron core 6 has the cross-shaped lower and upper arm portions 603 and 604 each of which is composed of a stack of cross-shaped flat plates vertically piled one over another. Due to this construction, eddy-current losses are induced in the lower and upper arm portions 603 and 604 at their center. Further, such eddy-current losses are also induced in other portions of the iron core 6 such as the junctions between the inner and outer leg portions 601 and 602 and the cross-shaped lower and upper arm portions 603 and 604 where these core portions are joined with or abut against each other. As a result, there arises a problem in that the high voltage developed at the secondary coil 4 upon interruption of the corrent supplied to the primary coil 3 is reduced.
  • the iron core 6 is composed of the annular inner leg portion 601, the planar outer leg portions 602 and the cross-shaped lower and upper arm portions 603 and 604 all of which are of different configurations, the number of component parts of the iron core 6 is relatively large, and hence fabrication and assembly of the respective component parts are inefficient and costly.
  • DE-A-3 423 524 discloses another type of ignition coil comprising an iron core section formed by a pair of first and second core members having the same U-channel shaped configuration, which improves the productivity of the entire iron core.
  • the present invention is intended to obviate the above-described problems of the prior art transformer according to the Abstract of JP-A-61 231 708.
  • An object of the present invention is to provide a high-voltage transformer and a method of making the same in which eddy-current losses in the iron core can be substantially avoided so that a voltage of a much higher magnitude is developed at a secondary coil.
  • Another object of the present invention is to provide a high-voltage transformer in which the respective component parts of an iron core have a simple and substantially uniform configuration thereby to improve productivity or assemblability of the entire iron core.
  • a further object of the present invention is to provide a high-voltage transformer and a method for making the same in which the number of junctions between the iron core component parts is greatly reduced to improve heat transmission therebetween, thereby expediting heat dissipation from the surfaces of the iron core which are exposed to the ambient air.
  • FIGS. 4A and 4B each show a schematic view of an iron core as to be used in connection with a high-voltage transformer as illustrated in the Figs. 1 and 2, wherein the iron core according to Fig. 4A or Fig. 4B is to replace the prior known iron core 6.
  • Fig. 4A shows an iron core section 610' in accordance with a first embodiment of the present invention.
  • the iron core section 610' comprises a pair of L-shaped first and second core members 611' and 612' which are composed of a plurality of L-shaped flat iron plates 611A' and 612A', respectively.
  • the first core member 611' has a laterally extending upper arm portion 611a' and an outer leg portion 611b' which extends downwards from the outer end of the upper arm portion 611a'.
  • the second core member 612' has a laterally extending lower arm portion 612a' and an outer leg portion 612b' which extends upwards from the inner end of the lower arm portion 621a'.
  • the outer leg portion 611b' of the first core member 611' is shorter than the inner leg portion 612a' of the second core member 612' so that when the upper and lower core members 611' and 612' are assembled, the upper end surface of the inner leg portion 612a' abuts against the upper arm portion 611a', whereas the lower end surface of the outer leg portion 611b' is spaced from the lower arm portion 612b' with a limited gap 613 formed therebetween.
  • the first and second core members 611' and 612' are slightly different in configuration from each other.
  • An iron core formed of the iron core sections 610' of this embodiment achieves all the effects and advantages as referred to above.
  • Fig. 4B shows a modification of the iron core section 610'. This modification is substantially similar to the iron core section 610' of Fig. 4A except for the fact that the relationship between the first and second core members 611' and 612' of Fig. 4A is reversed or turned upside down.
  • FIG. 5 A high-voltage transformer constructed in connection with iron core sections as illustrated in Figs. 4A or 4B was tested in terms of the secondary coil voltage versus the primary coil interruption current.
  • the primary and secondary coils 3 and 4 of the transformer were connected in an electrical circuit in the same manner as in Fig. 3, and the voltage developed at the secondary coil 4 was measured by changing the interruption current at the primary coil 3.
  • the results obtained are illustrated in Fig. 5 in which the primary coil interruption current is plotted as abscissa and the secondary coil voltage as ordinate.
  • the solid line indicates the transformer of the present invention, and the dashed line the conventional transformer 1 shown in Figs. 1 and 2. From this figure, it is clear that the transformer of the present invention provides a higher voltage at the secondary coil 4 than the conventional transformer 1 does.
  • a high-voltage transformer in connection with an iron core as described with reference to the Figs. 4A and 4B is fabricated or assembled in the manner as disclosed in claim 7 or claim 8.
  • each of the first and second core members of the iron core is formed of a plurality of stacked iron plates, it may be integrally formed from an iron blank as by forging.
  • four iron core sections are disposed around the cylindrical sleeve in a cross-shaped configuration, but the number of the iron core sections as required is not limited to this but any number of them may be employed.
  • two iron core sections may be disposed around the sleeve in diametrically opposite directions, or three iron core sections may be disposed around the sleeve and circumferentially spaced from each other at an angle of 120 degrees.
  • the bottom portion of the coil case may be open or closed with appropriate apertures being formed therethrough for receiving iron core sections as well as permitting heat dissipation therefrom.

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Insulating Of Coils (AREA)
  • Ignition Installations For Internal Combustion Engines (AREA)
  • Coils Of Transformers For General Uses (AREA)

Claims (8)

  1. Hochspannungstransformator, der aufweist:
    ein Spulengehäuse (2);
    eine zylindrische Buchse (5) in dem Spulengehäuse (2);
    eine Primärwicklung (3), die um die zylindrische Buchse (5) herum in dem Spulengehäuse (2) angeordnet ist;
    eine Sekundärwicklung (4), die um die Primärwicklung (3) herum in dem Spulengehäuse (2) angeordnet ist;
    einen Eisenkern (6), der eine Vielzahl von Eisenkernabschnitten (610') hat, die in dem Spulengehäuse (2) die Primär- und die Sekundärwicklung umgebend angeordnet sind, wobei jeder Eisenkernabschnitt (610') Kernelemente (611'; 612') aufweist, die mit den Enden aneinander anliegend zusammengesetzt sind, wobei aber an einer Stelle ein Luftspalt (613) verbleibt; und
    ein in das Spulengehäuse (2) gefülltes Harz (7), um die Primärwicklung (3) und die Sekundärwicklung (4) gegenüber dem Eisenkern elektrisch zu isolieren und sie dauerhaft an dem Spulengehäuse (2) festzulegen;
    dadurch gekennzeichnet
    daß die Eisenkernabschnitte (610') jeweils ein Paar von ersten (611') und zweiten (612') Kernelementen aufweisen, die nahezu die gleiche L-Konfiguration haben, wobei die ersten und zweiten Kernelemente (611'; 612') jeweils einen kürzeren Schenkelteil (611a', 612a') gleicher Länge und einen längeren Schenkelteil (611b'; 612b') geringfügig verschiedener Länge haben, so daß im zusammengefügten Zustand der Luftspalt resultiert.
  2. Hochspannungstransformator nach Anspruch 1,
    wobei jedes der ersten und zweiten Kernelemente (611'; 612') aus einer Vielzahl von flachen Eisenplatten gebildet ist, die nebeneinander geschichtet sind.
  3. Hochspannungstransformator nach Anspruch 1,
    wobei jedes der ersten und zweiten Kernelemente (611'; 612') aus einem einzigen Eisenrohling durch Schmieden integral geformt ist.
  4. Hochspannungstransformator nach Anspruch 1,
    wobei Kernabschnitte (610') um die zylindrische Buchse (5) herum so angeordnet sind, daß sie bei Betrachtung im Querschnitt senkrecht zu der Längsachse der zylindrischen Buchse einen Kern mit kreuzförmiger Konfiguration bilden.
  5. Hochspannungstransformator nach Anspruch 1,
    wobei Kernabschnitte (610') um die zylindrische Buchse (5) herum in diametral entgegengesetzten Richtungen um die Längsachse der zylindrischen Buchse angeordnet sind.
  6. Hochspannungstransformator nach Anspruch 1,
    wobei Kernabschnitte (610') um die zylindrische Buchse (5) herum angeordnet sind, um Kerne zu bilden, die umfangsmäßig um einen Winkel von 120° voneinander beabstandet sind.
  7. Verfahren zur Herstellung eines Hochspannungstransformators nach Anspruch 1, das die folgenden Schritte umfaßt:
    Formen einer Vielzahl von ersten L-förmigen Kernelementen integral mit einem Spulengehäuse auf solche Weise, daß es in diesem Spulengehäuse jeweils vertikal angeordnet und einer seiner Schenkel integral mit dem Bodenteil des Spulengehäuses verbunden ist;
    Anordnen einer Primärwicklung und einer Sekundärwicklung auf den ersten Kernelementen in dem Spulengehäuse, wobei die Sekundärwicklung um die Primärwicklung herum angeordnet ist;
    Anordnen einer Vielzahl von zweiten L-förmigen Kernelementen auf den ersten L-förmigen Kernelementen auf solche Weise, daß die zweiten Kernelemente mit den ersten Kernelementen zusammenwirken, um Eisenkernabschnittte zu bilden, die jeweils die Primär- und die Sekundärwicklung umgeben; und
    Einfüllen eines Harzes in das Spulengehäuse, so daß das Harz zwischen die Primär- und Sekundärwicklung und die Eisenkernelemente eindringt und erstarrt, um die Primär-  und die Sekundärwicklung gegenüber dem Eisenkern elektrisch zu isolieren sowie sie an dem Spulengehäuse festzulegen.
  8. Verfahren zur Herstellung eines Hochspannungstransformators nach Anspruch 1, das die folgenden Schritte umfaßt:
    Anbringen einer Sekundärwicklung um eine Primärwicklung herum;
    Zusammensetzen einer Vielzahl von ersten und zweiten L-förmigen Kernelementen auf der Primär- bzw. der Sekundärwicklung von der Innen- bzw. der Außenseite der Wicklungen, um Eisenkernabschnitte zu bilden, die jeweils die Primär- und die Sekundärwicklung umgeben;
    Anordnen der so zusammengesetzten Primär- und Sekundärwicklungen und der Eisenkernabschnitte in dem Spulengehäuse; und
    Einfüllen eines Harzes in das Spulengehäuse, so daß das Harz zwischen die Primär- und Sekundärwicklung und den Eisenkern eindringt und erstarrt, um die Primär- und die Sekundärwicklung gegenüber dem Eisenkern elektrisch zu isolieren sowie sie an dem Spulengehäuse festzulegen.
EP19870117994 1987-12-04 1987-12-04 Hochspannungstransformator und Verfahren zu seiner Herstellung Expired - Lifetime EP0318613B1 (de)

Priority Applications (2)

Application Number Priority Date Filing Date Title
EP19870117994 EP0318613B1 (de) 1987-12-04 1987-12-04 Hochspannungstransformator und Verfahren zu seiner Herstellung
DE19873781692 DE3781692T2 (de) 1987-12-04 1987-12-04 Hochspannungstransformator und verfahren zu seiner herstellung.

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP19870117994 EP0318613B1 (de) 1987-12-04 1987-12-04 Hochspannungstransformator und Verfahren zu seiner Herstellung

Publications (2)

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EP0318613A1 EP0318613A1 (de) 1989-06-07
EP0318613B1 true EP0318613B1 (de) 1992-09-09

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EP19870117994 Expired - Lifetime EP0318613B1 (de) 1987-12-04 1987-12-04 Hochspannungstransformator und Verfahren zu seiner Herstellung

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DE (1) DE3781692T2 (de)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
ITVR940055U1 (it) * 1994-09-14 1996-03-14 Apparecchiatura per lampade a scarica, con accensione e riaccensione istantanea con lampada calda, particolarmente per lampade illuminazio
JP3922251B2 (ja) * 2003-12-17 2007-05-30 三菱電機株式会社 点火コイル

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB199879A (en) * 1922-04-26 1923-07-05 British Lighting And Ignition Improvements in or relating to induction coils
GB542864A (en) * 1939-11-23 1942-01-29 Bbc Brown Boveri & Cie Improvements in and relating to transformers
GB584861A (en) * 1943-06-12 1947-01-24 Bendix Aviat Corp Improvements in groups of electrical transformers
US2701865A (en) * 1952-05-31 1955-02-08 Essex Wire Corp Ignition coil
FR2397051A1 (fr) * 1977-07-05 1979-02-02 Prospection & Sales Bobine d'allumage a enroulement fractionne et diodes incorporees
US4203404A (en) * 1978-03-13 1980-05-20 Texaco Inc. Distributorless ignition method and system for a multicylinder internal combustion engine
DE3423524C2 (de) * 1984-06-26 1986-10-02 Bertos AG, Glarus Zündspule

Also Published As

Publication number Publication date
DE3781692D1 (de) 1992-10-15
DE3781692T2 (de) 1993-01-21
EP0318613A1 (de) 1989-06-07

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