JP2006287089A - Ignition coil for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance reliability of high voltage endurance by preventing dielectric breakdown from occurring between a secondary coil and an outer circumferential core. <P>SOLUTION: The ignition coil 100 for internal combustion engine comprises tubular primary coil bobbin 3 and secondary coil bobbin 4 arranged concentrically while being applied with a primary coil 1 and a secondary coil 2, respectively, and a core section 7 consisting of a central core 5 located in the tube of the primary coil bobbin 3 and an outer circumferential core 6 located on the outer circumference of the secondary coil bobbin 4 and forming a closed magnetic path of magnetic lines of force wherein electromagnetic induction is caused by interrupting a current flowing through the primary coil 1 and a counter-electromotive force thus induced is stepped up through the secondary coil 2 to generate a high voltage. The circumferential core 6 is constituted by combining a plurality of split cores 6a and 6b and the splitting position P is close to the low voltage region R2 of the secondary coil 2. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a molded internal combustion engine ignition coil that supplies a high voltage in order to generate a spark discharge, for example, in an ignition plug of an automobile engine.

  5 and 6 are views showing an example of a main part of a conventional ignition coil for an internal combustion engine, FIG. 5 is a perspective view, and FIG. 6 is a bottom view. In these drawings, an ignition coil 200 for an internal combustion engine includes a cylindrical primary coil bobbin (not shown) and a secondary coil bobbin 24 that are wound around a primary coil (not shown) and a secondary coil 22 and arranged concentrically. And an iron core portion 27 which forms a closed magnetic path of magnetic lines of force, which includes a central iron core 25 located in the cylinder of the primary coil bobbin and an outer iron core 26 located on the outer periphery of the secondary coil bobbin 24.

  The terminal portion 22a of the secondary coil 22 extends from the terminal box 22b and supplies a high-voltage current generated in the secondary coil 22 to the spark plug via a high-voltage terminal or the like.

  The outer peripheral iron core 26 is composed of a combination of divided iron cores 26 a and 26 b divided into a plurality of parts, and the divided portion P is located in the vicinity of the high voltage region R 1 of the secondary coil 22. Thus, the outer peripheral iron core 26 is divided in order to improve the assembling property at the time of manufacture, and the division is performed along the height direction of the outer peripheral iron core.

  However, as in the conventional case, when the divided portion P of the outer peripheral iron core 26 is located in the high voltage region R1 of the secondary coil 22, the high voltage region R1 and the edge of the divided core 26a at the divided portion P are provided. The electric field concentrates between 260a and the edge portion 260b of the divided iron core 26b, and there are cases where dielectric breakdown occurs at the limit point of high voltage durability. For this reason, the reliability of the high voltage endurance of the ignition coil 200 for an internal combustion engine has been reduced.

  The present invention has been proposed in view of the above, and provides an ignition coil for an internal combustion engine that can prevent a dielectric breakdown that has occurred between a secondary coil and an outer peripheral iron core and can improve the reliability of high-voltage durability. The purpose is to do.

  In order to achieve the above object, the invention described in claim 1 includes a cylindrical primary coil bobbin and a secondary coil bobbin in which a primary coil and a secondary coil are wound and arranged concentrically, and in the cylinder of the primary coil bobbin. A central core that is located on the outer periphery of the secondary coil bobbin, and an iron core that forms a closed magnetic path for the lines of magnetic force. In an internal combustion engine ignition coil that generates a high voltage by boosting a counter electromotive force generated by induction with a secondary coil, the outer peripheral iron core is constituted by a combination of a plurality of divided iron cores, and It is characterized by being in the vicinity of the low voltage region of the secondary coil.

  In the ignition coil for an internal combustion engine according to the present invention, the division portion of the outer peripheral iron core is provided in the vicinity of the low voltage region of the secondary coil, so that dielectric breakdown that has occurred between the secondary coil and the outer iron core is prevented. The reliability of voltage durability can be improved.

  Embodiments of the present invention will be described in detail with reference to the drawings.

  1 to 3 are views showing an example of an essential part of an ignition coil for an internal combustion engine according to the present invention. FIG. 1 is a perspective view, FIG. 2 is a bottom view, and FIG. In these drawings, an ignition coil 100 for an internal combustion engine includes a cylindrical primary coil bobbin 3 and a secondary coil bobbin 4 that are wound around a primary coil 1 and a secondary coil 2 and arranged concentrically, and an in-cylinder of the primary coil bobbin 3. And an iron core portion 7 that forms a closed magnetic path of magnetic lines of force, which includes a central iron core 5 located on the outer periphery and an outer iron core 6 located on the outer periphery of the secondary coil bobbin 4.

  The terminal portion 2a of the secondary coil 2 extends from the terminal box 2b and supplies a high-voltage current generated in the secondary coil 2 to the spark plug 31 (FIG. 4) via a high-voltage terminal or the like.

  The outer peripheral iron core 6 is constituted by a combination of divided cores 6 a and 6 b divided into a plurality of parts, and the divided part P is located in the vicinity of the low voltage region R <b> 2 of the secondary coil 2. The division is performed along the height direction of the outer peripheral iron core 6.

  FIG. 4 is a circuit configuration diagram of an ignition coil for an internal combustion engine according to the present invention. In FIG. 4, the primary coil 1 has one end connected to the power source and the other end connected to the collector terminal 13 of the power transistor 11. The secondary coil 2 has one end connected to one end of the primary coil 1 and the other end connected to a spark plug 31. The iron core 7 magnetically couples the primary coil 1 and the secondary coil 2. The power transistor 11 has a signal terminal 12 connected to an engine control unit (not shown) and a ground terminal 14 connected to the ground.

  In the circuit configuration described above, when a control signal (in the form of a pulse) is supplied to the signal terminal 12 of the power transistor 11 from an engine control unit (not shown), the power transistor 11 becomes conductive, so that the ignition for the internal combustion engine is performed from the power source. When a current flows through the primary coil 1 of the coil 100 and the control signal is turned off, the power transistor 11 cuts off the current flowing through the primary coil 1, and the current of the primary coil 1 is cut off. High voltage is generated. The high voltage generated in the secondary coil 2 is supplied to the spark plug 31 via the terminal end 2a and the like, thereby generating a spark discharge in the spark plug 31 and burning the fuel of the internal combustion engine such as the engine. .

  As described above, in this embodiment, since the division point P of the outer peripheral core 6 is provided in the vicinity of the low voltage region R2 of the secondary coil 2, the low voltage region R2 and the division core 6a at the division point P are provided. Electric field concentration between the edge 60a and the edge 60b of the divided iron core 6b can be reduced. Therefore, it is possible to prevent the dielectric breakdown occurring between them and improve the reliability of the high voltage durability.

It is a perspective view which shows an example of the principal part of the ignition coil for internal combustion engines of this invention. It is a bottom view which shows an example of the principal part of the ignition coil for internal combustion engines of this invention. It is AA sectional drawing of FIG. It is a circuit block diagram of the ignition coil for internal combustion engines of this invention. It is a perspective view which shows an example of the principal part of the ignition coil for internal combustion engines which has arrange | positioned the conventional permanent magnet. It is a bottom view which shows an example of the principal part of the ignition coil for internal combustion engines which has arrange | positioned the conventional permanent magnet.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Primary coil 2 Secondary coil 2a End part of secondary coil 2b End box 3 Primary coil bobbin 4 Secondary coil bobbin 5 Central iron core 6 Outer iron core 6a Divided iron core 6b Divided iron core 7 Iron core 11 Power transistor 12 Signal terminal 13 Collector terminal 14 Ground Terminal 31 Spark plug 60a Edge of split iron core 60b Edge of split iron core 100 Ignition coil for internal combustion engine P Split location R1 High voltage region R2 Low voltage region

Claims (1)

It consists of a cylindrical primary coil bobbin and a secondary coil bobbin that are wound around a primary coil and a secondary coil and arranged concentrically, and a central iron core located in the cylinder of the primary coil bobbin and an outer iron core located on the outer periphery of the secondary coil bobbin. And an iron core part that forms a closed magnetic circuit of magnetic lines of force, and electromagnetic induction is caused by interrupting the current that is passed through the primary coil, and the back electromotive force generated by the electromagnetic induction is boosted by the secondary coil to generate a high voltage In an internal combustion engine ignition coil for generating
The outer peripheral iron core is composed of a combination of divided iron cores divided into a plurality of parts, and the division location is in the vicinity of the low voltage region of the secondary coil.
An ignition coil for an internal combustion engine.

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