EP1128403A1 - Ignition coil for an internal combustion engine - Google Patents

Ignition coil for an internal combustion engine Download PDF

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Publication number
EP1128403A1
EP1128403A1 EP01104407A EP01104407A EP1128403A1 EP 1128403 A1 EP1128403 A1 EP 1128403A1 EP 01104407 A EP01104407 A EP 01104407A EP 01104407 A EP01104407 A EP 01104407A EP 1128403 A1 EP1128403 A1 EP 1128403A1
Authority
EP
European Patent Office
Prior art keywords
winding
high voltage
primary
bobbin
ignition 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.)
Withdrawn
Application number
EP01104407A
Other languages
German (de)
English (en)
French (fr)
Inventor
Takanori Satoo
Ryozo Takeuchi
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.)
Hitachi Ltd
Original Assignee
Hitachi 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 Hitachi Ltd filed Critical Hitachi Ltd
Publication of EP1128403A1 publication Critical patent/EP1128403A1/en
Withdrawn legal-status Critical Current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
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/28—Coils; Windings; Conductive connections
    • H01F27/32—Insulating of coils, windings, or parts thereof
    • H01F27/324—Insulation between coil and core, between different winding sections, around the coil; Other insulation structures
    • H01F27/325—Coil bobbins
    • 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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F5/00—Coils
    • H01F5/02—Coils wound on non-magnetic supports, e.g. formers
    • H01F2005/025—Coils wound on non-magnetic supports, e.g. formers wound on coaxial arrangement of two or more formers
    • 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
    • H01F2038/122—Ignition, e.g. for IC engines with rod-shaped core
    • 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
    • H01F27/28—Coils; Windings; Conductive connections
    • H01F27/32—Insulating of coils, windings, or parts thereof
    • H01F27/327—Encapsulating or impregnating

Definitions

  • the present invention relates to an ignition coil for an internal combustion engine. More particularly, the invention relates to an ignition coil for an internal combustion engine which can be entirely or partly received within a plug hole of the engine.
  • an ignition coil received within a plug hole of an internal combustion engine has been known (for example, "Spark Ignition Device for Internal Combustion Engine” disclosed in Japanese Patent Application Laid-Open No. 8-293418(1996) and Japanese Patent Application Laid-Open No. 10-22144(1998).
  • the ignition coil of this type is also referred to an independent ignition type ignition coil since it is installed in each individual cylinder.
  • Arrangement of the coil housed within a coil casing is a so-called internal secondary winding system, in which a secondary winding is arranged inside and a primary winding is arranged outside or so called external secondary winding system, in which the primary winding is arranged inside and the secondary winding is arranged outside.
  • the internal secondary winding system arranges a center core at the center portion of the coil casing, the secondary winding wound around a secondary bobbin surrounding the outer periphery of the center core, and the primary winding wound around a primary bobbin outside of the secondary winding surrounding the outer periphery thereof in coaxial manner.
  • the ignition coil Since the ignition coil generates a high voltage to be supplied to an ignition plug, insulation between respective components within the coil casing is ensured by filling and curing a liquid state insulative resin within the coil casing.
  • An object of the present invention to improve reliability and durability of an ignition coil by enhancing breakdown voltage at an interface between a flange portion of a primary bobbin and a coil casing as set forth above.
  • the present invention basically proposes, in an ignition coil of an internal secondary winding system, two or more flange portions are arranged in the flange portion on the side of high voltage side of the secondary winding among the first bobbin, and between the flanges, only insulative resin being filled instead of winding the primary winding.
  • an insulative resin filling region is certainly provided between the flange portions provided in the vicinity of the end portion on high voltage side of the ignition coil.
  • the space between the flange portions serves to provide an anchor effect to make it difficult to cause peeling off between the flange portion and the coil casing located in the vicinity thereof. Even if peeling between the flange portion of the primary winding and the coil casing is caused, bonding ability between the insulative resin filling region and the coil casing can be certainly maintained to enhance breakdown voltage of the interface between the primary bobbin and the coil casing.
  • a creepage distance from the first winding to the high voltage member e.g. secondary winding and high pressure terminal or the like
  • the high voltage member e.g. secondary winding and high pressure terminal or the like
  • Fig. 1 is a longitudinal section of one embodiment of an ignition coil for an internal combustion engine according to the present invention
  • Fig. 2 is a longitudinal section of a condition where the foregoing ignition plug is installed within a plug hole.
  • Fig. 2 1 denotes an internal combustion engine
  • 2 denotes a cylinder head in an engine block.
  • An ignition coil 10 is entirely or partly inserted within a plug hole 5 of the cylinder head and is electrically connected to an ignition plug 3.
  • 4 denotes a combustion chamber of the engine.
  • a casing of the ignition coil 10 is constructed with a coil casing 19 housing a coil parts and a circuit casing (hereinafter referred to as igniter casing) 19' housing a spark ignition driver circuit (hereinafter referred to as igniter) 18.
  • the igniter casing 19' is formed integrally with a connector casing 30.
  • a plurality of terminals 31 are arranged (in the drawings, only one terminal 31 is illustrated for convenience of illustration, but in practice, there are power source terminal, a grounding terminal and a signal terminal).
  • a center core 11 is arranged at the center portion.
  • a secondary winding 15 wound around a secondary bobbin 14 is arranged,
  • a primary winding 17 wound around a primary bobbin 16 is arranged.
  • the first and second bobbins 14 are formed of an insulative resin, such as PPS, PGT, Noryl or the like.
  • the primary winding 17 is a double layer winding, for example (in Fig. 1, it is shown as single layer winding for convenience of illustration). Winding is started on the side of a flange portion 161 provided at one end of the primary bobbin 16. When the first layer of winding reaches a flange portion provided on the other end of the bobbin 16, it is turned to start winding of the second layer from the side of the flange portion 161. One end on winding end side is connected to a grounding terminal.
  • a flange portion 163 for another purpose is provided.
  • the flange portion 163 is for enhancing insulation performance between the primary winding and a high voltage member (secondary winding, high voltage terminal and so forth) in cooperation with the flange portion 162. This point will be discussed later.
  • the secondary winding is divided via a plurality of flange portions on the secondary bobbin 14 to have higher voltage toward winding end side (one end of the secondary bobbin).
  • the end portion of the secondary winding on the winding end side is electrically connected to a connection spring 22 for high voltage and thus to a high voltage terminal 23,
  • a high voltage diode 26 is installed on the high voltage side end of the secondary bobbin 14.
  • 12 denotes a permanent magnet
  • 13 denotes a rubber like elastic member having insulation ability
  • 21 denotes a side code mounted on the outer periphery of the coil casing.
  • a liquid state insulative resin e.g. epoxy resin
  • a liquid state insulative resin is injected to fill and cure for forming the insulative resin portion 20.
  • a rubber boots 25 is fitted on the lower end of the coil casing 19. Through the rubber boots 25 and a spring 24, the ignition plug 3 (see Fig. 2) is secured.
  • an interface between the outer periphery of the flange portion 162 of the primary bobbin and the inner periphery of the coil casing 19 tends to cause peeling off to be a cause of lowering of breakdown voltage.
  • Lowering of the breakdown voltage can be a cause of leakage of high voltage between the primary winding 17 and the high voltage member such as the secondary winding 15 and high voltage terminal 23.
  • another flange portion 163 is provided in addition to the flange portion 162 on the high voltage side end of the secondary winding. Between the flange portions 162 and 163, the primary winding is not wound and only insulative resin is filled.
  • Fig. 3 is an illustration showing a longitudinal section of the primary bobbin 16, on which the primary winding 17 is wound
  • Fig. 4 is an illustration showing a perspective view of the primary bobbin 16.
  • the primary bobbin 16 is arranged two flange portions 162 and 163 on high voltage side of the ignition coil.
  • an insulative resin filling region where the primary winding is not present is provided between the flange portion 162 and the flange portion 163.
  • the insulative resin between the flange portions 162 and 163 serves for providing an anchor effect to make it difficult to cause peeling off between the flange portions 162, 163 and the coil casing 19. Even if peeling is caused between the flange portion and the coil casing, since bonding ability between the insulative resin filling region and the coil casing can be maintained to make the breakdown voltage at the interface between the primary bobbin and the coil casing high.
  • a distance between the flange portion portions 162 and 163 has to be large enough to sufficiently impregnate the insulative resin. As an example, it should be a dimension greater than or equal to the minimum thickness of the flange portion, e.g. greater than or equal to 1 mm.
  • the function of the space between the flange portion portions in these known art is to eliminate concentration of electric field which can be cause when lead line on the high voltage side of the secondary winding is led to the high voltage terminal by single conductor, by winding the high voltage lead wire between the flange portions in single layer to lead to the high voltage terminal. Therefore, these performs different function to the present invention, and no prior art which can expect the function and effect as achieved by the present invention has been present.
  • Figs. 5 to 8 show sections or perspective view showing modification of the primary bobbin to be employed in the foregoing embodiment.
  • Fig. 5 shows an example, in which opposing surfaces of the foregoing flange portions 162 and 163 of the primary bobbin 16 are tapered to be widen toward outside.
  • one of two flange portions 162 and 63 of the primary winding is provided smaller height in radial direction than the other flange portion 163 in the extent of ⁇ Ah.
  • the height of the flange portion 163 is 1.2 mm and the height of the flange portion 162 is 0,7 mm to set the ⁇ Ah about 0.5 mm.
  • positioning of the primary bobbin in the radial direction can be done by the flange portion 163 having greater flange portion height, and a gap of ⁇ Ah is maintained between the flange portion 162 having smaller flange portion height and the coil casing to permit filling of the insulative resin in rich within the gap portion to improve bonding ability between the flange portion 162 and the coil casing to increase breakdown voltage at the interface between the flange portion and the coil casing and to further certainly suppress occurrence of insulation failure between the primary winding and the high voltage member.
  • the primary bobbin 16 shown in Fig. 7 is provided with groove portions 161a to 163a in axial direction of the flange portions 161 to 163 set forth above. By providing threes groove portions, flowability of the liquid state insulative resin upon injection of the insulative resin.
  • each flange portion portion One of more of these grooves are arranged on each flange portion portion.
  • the groove portions 162a and 163a provided on the flange portions 162 and 163 are arranged in staggered fashion so as not to overlap with the coil casing (ignition coil).
  • the flange portion 163 on the side close to the high voltage side of the ignition coil (shortest side of the bobbin) is provided a ridge 163b.
  • the ridge 163b is formed on the side surface directed to the high voltage side of the ignition coil in the flange portion 163.
  • the ridge portion 163b has a structure to engage with a recessed portion 33 provided in the primary bobbin receptacle portion of the coil casing as shown in Fig. 9 to provide greater insulation distance (creepage distance) between the primary winding 17 and the high voltage member. Accordingly, insulation failure between the primary winding 17 and the high voltage member can be more certainly prevented.
  • the breakdown voltage at the interface between the flange position of the primary bobbin and the coil casing can be enhanced. Also, since the creepage distance between the primary winding to the high voltage member, such as the secondary winding, the high voltage terminal or the like becomes large to restrict insulation failure between the primary winding and the high voltage member.

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Ignition Installations For Internal Combustion Engines (AREA)
EP01104407A 2000-02-28 2001-02-26 Ignition coil for an internal combustion engine Withdrawn EP1128403A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2000055998A JP2001244135A (ja) 2000-02-28 2000-02-28 内燃機関用点火コイル
JP2000055998 2000-02-28

Publications (1)

Publication Number Publication Date
EP1128403A1 true EP1128403A1 (en) 2001-08-29

Family

ID=18577030

Family Applications (1)

Application Number Title Priority Date Filing Date
EP01104407A Withdrawn EP1128403A1 (en) 2000-02-28 2001-02-26 Ignition coil for an internal combustion engine

Country Status (2)

Country Link
EP (1) EP1128403A1 (ja)
JP (1) JP2001244135A (ja)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2848330A1 (fr) * 2002-12-05 2004-06-11 Denso Corp Dispositif de bobine d'allumage monte dans un element de trou de bougie

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4487190B2 (ja) 2004-02-04 2010-06-23 株式会社デンソー スティック型点火コイル
JP2008034560A (ja) * 2006-07-27 2008-02-14 Denso Corp 点火コイル

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1992007370A1 (de) * 1990-10-11 1992-04-30 Robert Bosch Gmbh Hochspannungsanschlüsse an zündspulen
JPH0945571A (ja) * 1995-07-27 1997-02-14 Hanshin Electric Co Ltd 内燃機関用点火コイルの２次コイルの製作方法

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1992007370A1 (de) * 1990-10-11 1992-04-30 Robert Bosch Gmbh Hochspannungsanschlüsse an zündspulen
JPH0945571A (ja) * 1995-07-27 1997-02-14 Hanshin Electric Co Ltd 内燃機関用点火コイルの２次コイルの製作方法

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 1997, no. 06 30 June 1997 (1997-06-30) *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2848330A1 (fr) * 2002-12-05 2004-06-11 Denso Corp Dispositif de bobine d'allumage monte dans un element de trou de bougie

Also Published As

Publication number Publication date
JP2001244135A (ja) 2001-09-07

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