JP2000182860A - Ignition coil for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate a gap between a permanent magnet provided between a laminated iron core inserted in a cylinder part of a primary coil bobbin and wound iron core located on the outer periphery of a secondary coil bobbin and the both iron cores to realize a small-sized, light-weight ignition coil. SOLUTION: This ignition coil includes primary and secondary coil bobbins 3 and 4 of a cylindrical shape, provided concentrically and having primary and secondary coils 1 and 2 respectively, an iron core part forming a closed magnetic path in which the magnetic force lines pass through the cylindrical inner periphery of the primary bobbin 3 and through an outer periphery of the secondary bobbin 4, and a permanent magnet 8 for applying magnetic reverse bias to the iron core part. In the case, the iron core part has a laminated iron core 5 located within the cylinder of the primary bobbin 3 and a wound iron core 6 located to the outer periphery of the secondary bobbin 4, the end face of the permanent magnet 8 provided between the iron cores 5 and 6 on the side of the laminated iron core 5 is formed flat corresponding to the end face of the laminated core 5, and the end face of the magnet provided with the wound core 6 is formed into an arcuate surface corresponding to the inner peripheral surface of the wound core 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molded type internal combustion engine ignition coil for supplying a high voltage to generate a spark discharge in, for example, a spark plug of an automobile engine, and more particularly to an internal combustion engine which is required to be miniaturized. The present invention relates to an improvement in an ignition coil for a vehicle.

[0002]

2. Description of the Related Art The applicant has previously magnetically coupled two magnetic cores in series between a laminated core whose magnetic lines of force pass through the inner periphery of a primary coil bobbin and a wound core which passes through the outer periphery of a secondary coil bobbin. Japanese Patent Application No. 10-1283 proposes an ignition coil for an internal combustion engine which is capable of increasing the output in addition to miniaturization by disposing a permanent magnet.

[0003] The improved ignition coil for an internal combustion engine includes:
It has a schematic configuration as shown in FIG. 3 and FIG. That is, a cylindrical primary coil bobbin 3 and a secondary coil bobbin 4 in which the primary coil 1 and the secondary coil 2 are respectively wound and arranged concentrically, and a laminated iron core 5 whose magnetic field lines pass through the inner circumference of the cylinder of the primary coil bobbin 3 and It includes a wound iron core 6 forming a closed magnetic path through the outer periphery of the secondary coil bobbin 4, and a permanent magnet 8 for applying a reverse bias to the magnetic circuit.

More specifically, the primary coil bobbin 3 is integrally formed in a cylindrical shape with an electrically insulating material such as a synthetic resin, and the primary coil 1 is wound around the outer periphery thereof. On the other hand, the secondary coil bobbin 4 is disposed concentrically on the outer periphery of the primary coil 1 and is made of, for example, an electrically insulating material such as a synthetic resin. Also,
The secondary coil bobbin 4 is integrally formed with a plurality of flanges 9 functioning as partitions for dividing and winding the secondary coil 2. That is, the secondary coil bobbin 4 is partitioned by a plurality of flanges 9 provided circumferentially at a plurality of positions in the length direction.
The space between the two is a divided winding groove of the secondary coil 2. And
On the secondary coil bobbin 4, for example, the secondary coil 2 having a turn ratio of 1:70 to 120 with the primary coil 1 is provided with each flange 9
As a partition member.

The above-mentioned laminated iron core 5 is formed by laminating strip-shaped silicon steel sheets and is formed in a substantially prismatic shape, and is inserted into a rectangular cylinder of the primary coil bobbin 3. On the other hand, wound core 6
Is formed by winding a silicon steel plate having a relatively small thickness at an outer peripheral position of the secondary coil bobbin 4 in a circular or elliptical shape. Then, both end surfaces of the laminated core 5 and the inner peripheral surface of the wound core 6 are joined by an adhesive, welding, or the like to form a closed magnetic circuit, thereby forming a magnetic circuit.

The primary coil 1 and the primary terminal 11 and the secondary coil 2 and the high voltage terminal 12 are electrically connected to each other. The high-voltage current is supplied from a high-voltage terminal 12 to a spark plug through a high-tension cord (not shown), and a spark is generated between electrodes at the tip of the plug.

Then, an insulating thermosetting resin 13 such as an epoxy resin is injected from the opening end of the insulating case 10 so that the primary coil 1 and the secondary coil 2 inside the insulating case 10 are concentrically formed. Laminated core 5 and wound core 6
In addition, the permanent magnet 8 and the like are fixed at predetermined positions.

[0008]

In the conventional ignition coil for an internal combustion engine constructed as described above, the permanent magnet 8 interposed between the laminated core 5 and the wound core 6 is a rectangular parallelepiped or a cylindrical body. Since the shape does not match the arc shape of the wound core 6 or the shape of the end of the laminated core 5, a gap is generated at the joint between the laminated core 5, the wound core 6 and the permanent magnet 8. For this reason, the outer diameter of the ignition coil becomes large, and there is a disadvantage that the whole ignition coil is prevented from being reduced in size and weight. Further, there is a problem that a gap is formed between the two cores 5 and 6 forming the closed magnetic circuit and the permanent magnet 8 so that the efficiency of the magnetic circuit is reduced and the output of the ignition coil is reduced. The present invention has been proposed in view of the above, and a permanent magnet inserted between a laminated core inserted into the cylinder of the primary coil bobbin and a wound core located on the outer peripheral portion of the secondary coil bobbin, and the permanent magnet An object is to eliminate a gap generated between them.

[0009]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a cylindrical primary coil bobbin and a secondary coil bobbin in which a primary coil and a secondary coil are wound and concentrically arranged, respectively. In an ignition coil of an internal combustion engine having an iron core part forming a closed magnetic path through the inner circumference of the cylinder of the coil bobbin and the outer circumference of the secondary coil bobbin, and a permanent magnet for applying a magnetic reverse bias to the iron core part,
The permanent magnet, which is composed of a laminated core positioned in the cylinder of the primary coil bobbin and a wound core positioned on the outer periphery of the secondary coil bobbin, is disposed between the laminated core and the wound core. Is formed on a flat surface corresponding to the end surface of the laminated core, and the end surface on the wound core side is formed on an arc surface corresponding to the inner peripheral surface of the wound iron core. Therefore, there is no gap between the permanent magnet and the wound core, and the maximum outer diameter of the wound core can be reduced. In addition, since the gap between the permanent magnet and the wound iron core is eliminated, the efficiency of the magnetic circuit is improved, and the output of the ignition coil is improved.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a diagram showing a longitudinal section of an ignition coil for an internal combustion engine according to the present invention, and FIG. 2 is a sectional view taken along line XX of FIG.

In these drawings, an ignition coil for an internal combustion engine includes a cylindrical primary coil bobbin 3 and a secondary coil bobbin 4 in which a primary coil 1 and a secondary coil 2 are wound and concentrically arranged, respectively, and the primary coil bobbin. 3 and a wound core 6 forming a closed magnetic path at the outer peripheral portion of the secondary coil bobbin 4 (secondary coil 2).

The primary coil bobbin 3 is integrally formed in a rectangular cylindrical shape with an electrical insulating material such as a synthetic resin, and the primary coil 1 is wound around the outer periphery thereof. On the other hand, the secondary coil bobbin 4 is disposed concentrically on the outer peripheral portion of the primary coil 1 and is made of, for example, an electrically insulating material such as a synthetic resin. The secondary coil bobbin 4 is integrally formed with a plurality of flange portions 9 functioning as partitions for winding the secondary coil 2 in a divided manner. That is, the secondary coil bobbin 4 is partitioned by the flanges 9 provided circumferentially at a plurality of locations in the length direction, and the divided winding grooves of the secondary coil 2 are formed between the respective flanges 9. The secondary coil bobbin 4 has, for example, a turn ratio of 1:70 to the primary coil 1.
The secondary coil 2 which is 120 is wound in divided windings with each flange 9 as a partition member.

The laminated iron core 5 is formed by laminating strip-shaped silicon steel sheets to form a prismatic shape, and is inserted into a rectangular cylinder of the primary coil bobbin 3. On the other hand, the wound iron core 6 is formed by winding a relatively thin silicon steel plate in a circular shape, an elliptical shape, or a square shape at an outer peripheral position of the secondary coil bobbin 4. Permanent magnets 8 are disposed at both left and right ends of the laminated core 5, and the end face of the permanent magnet 8 on the side of the wound core 6 is formed into an arc surface corresponding to the shape of the inner peripheral surface of the wound core 6. The gap between the permanent magnet 8 and the wound core 6 is eliminated. The end face of the laminated core 5 and the other end face of the permanent magnet 8 are
Close contact between flat surfaces. Then, the inner peripheral surface of the wound core 6 and the permanent magnet 8 and the outer end surface of the laminated core 5 and the permanent magnet 8 are joined by an adhesive or welding to form a closed magnetic circuit, thereby forming a magnetic circuit. .

The primary coil 1 and the primary terminal 11 and the secondary coil 2 and the high voltage terminal 12 are electrically connected to each other. Is supplied from the high voltage terminal 12 to the ignition plug via the high tension cord, and a spark is generated between the electrodes at the tip.

Then, an insulating thermosetting resin 13 such as an epoxy resin is injected from the opening end of the insulating case 10, whereby the primary coils 1,
The secondary coil 2 is fixed concentrically, and the laminated iron core 5, the wound iron core 6, the permanent magnet 8 and the like are fixed at predetermined positions. Note that the end of the primary coil bobbin 3 protrudes into an opening provided in the wall of the insulating case 10 to close the opening.

As described above, in this embodiment, since the shape of the permanent magnet 8 is a so-called kamaboko type in accordance with the arc shape of the wound iron core 6, a gap generated in the magnetic circuit is eliminated. In addition, the maximum outer diameter of the wound iron core 6 can be reduced. Also, by eliminating the gap between the magnetic circuits, the magnetic resistance of the magnetic circuit is reduced, and the efficiency of the magnetic circuit is improved.
A sufficient output as an ignition coil can be obtained with a minimum iron core cross-sectional area.

As described above, the present invention has been described based on the illustrated embodiments. However, the present invention is not limited to the above-described embodiments, but may be modified as long as the configuration described in the claims is not changed. And so on.

[0018]

Since the present invention has the above-described configuration,
The following effects can be obtained. The shape of the permanent magnet inserted between the laminated core whose magnetic lines of force pass through the inner periphery of the cylinder of the primary coil bobbin and the wound core passing through the outer periphery of the secondary coil bobbin is determined by the shape of the outer end face of the laminated core and the inner peripheral surface of the wound core. Therefore, there is no gap in the magnetic circuit, the maximum outer diameter of the wound iron core can be reduced, and the size and weight of the ignition coil can be reduced. Further, since there is no gap in the magnetic circuit, the magnetic resistance is reduced, the efficiency of the magnetic circuit is remarkably improved, and the iron core can be constituted by the minimum iron core material, which greatly contributes to the reduction in size and weight.

[Brief description of the drawings]

FIG. 1 is a longitudinal section of a main part of an ignition coil for an internal combustion engine according to the present invention.

FIG. 2 is a sectional view taken along line XX of FIG.

FIG. 3 is a longitudinal sectional view of a main part of a conventional ignition coil for an internal combustion engine.

FIG. 4 is a sectional view taken along line YY of FIG. 3;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Primary coil 2 Secondary coil 3 Primary coil bobbin 4 Secondary coil bobbin 5 Laminated iron core 6 Winding iron core 8 Permanent magnet 9 Flange part 10 Insulation case 11 Primary terminal 12 High voltage terminal 13 Thermosetting resin

Claims (1)

[Claims] 1. A cylindrical primary coil bobbin and a secondary coil bobbin in which a primary coil and a secondary coil are respectively wound and concentrically arranged, and lines of magnetic force pass through the inner circumference of the primary coil bobbin and the outer circumference of the secondary coil bobbin. An iron core forming a closed magnetic circuit, a permanent magnet for applying a magnetic reverse bias to the iron core,
In the ignition coil of an internal combustion engine having the above, the core portion is composed of a laminated core located in the cylinder of the primary coil bobbin, and a wound core located on the outer periphery of the secondary coil bobbin. The permanent magnets placed between
The end face on the laminated core side is formed on a flat surface corresponding to the end face of the laminated core, and the end face on the wound core side is formed on an arc surface corresponding to the inner peripheral surface of the wound core. Ignition coil for internal combustion engine.