JPH10223463A - Ignition coil for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the size of a molded type ignition coil for internal combustion engine and to increase the output of the coil. SOLUTION: An ignition coil 1 for internal combustion engine is provided with cylindrical primary and secondary coil bobbins 2 and 4, which are respectively wound with primary and secondary coils 3 and 5 and arranged concentrically and an iron core section 10, which forms a closed magnetic path through the inner periphery of the cylindrical primary coil bobbin 2 and the outer periphery of the cylindrical secondary coil bobbin 4. In this coil 1, the secondary coil bobbin 4 is divided into parts by flange sections 41 which are installed to the periphery of the bobbin 4 at a plurality of locations in the length direction of the bobbin 4, and the section between each flange section 41 is used as one divided winding groove of the secondary coil 5. In addition, each flange section 41 is constituted so that the section 41 becomes higher at the center of the bobbin 4 and becomes successively lower towards both sides of the bobbin 4.

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 ignition coil.

[0002]

2. Description of the Related Art A conventional mold-type ignition coil for an internal combustion engine will be described with reference to FIGS.

FIG. 5 is a longitudinal sectional view of a conventional ignition coil for an internal combustion engine, and FIG. 6 is a sectional view taken along line YY of FIG. In these figures, a conventional internal combustion engine ignition coil 1A includes a cylindrical primary coil bobbin 2A and a secondary coil bobbin 4A in which a primary coil 3A and a secondary coil 5A are wound and concentrically arranged, respectively, and the primary coil bobbin 2A. And a core portion 100A forming a closed magnetic path through the inner circumference of the cylinder and the outer circumference of the secondary coil bobbin 4A.

The iron core portion 100A is formed by joining the ends of laminated iron cores 110A and 120A of a silicon steel sheet having a substantially E-shape to each other by an adhesive or welding, and forms a closed magnetic circuit as a whole. Make up the circuit.

[0005] The primary coil bobbin 2A is integrally formed of an electrical insulating material such as a synthetic resin, for example, and a primary coil 3A is wound around the outer periphery thereof.

The secondary coil bobbin 4A is disposed concentrically around the primary coil 3A, is made of an electrically insulating material such as a synthetic resin, and has a secondary coil 5A.
Are integrally molded with a plurality of flanges 41A functioning as a partition for winding the part. The secondary coil bobbin 4A has, for example, a winding ratio of 1: 1 with the primary coil 3A.
Secondary coils 5A of 80 to 120 are wound in divided windings with each flange 41A as a partition.

Further, an insulating case 6A molded of an insulating material such as a synthetic resin is provided on the outer periphery of the secondary coil 5A,
A primary terminal 7A is disposed at one end of the insulating case 6A,
A high voltage terminal 8A is provided at the other end.

Further, the primary coil 3A and the primary terminal 7A, and the secondary coil 5A and the high voltage terminal 8A are electrically connected to each other. The high-voltage current is supplied to the ignition plug from the high-voltage terminal 8A via a spring.

The ignition coil (so-called molded coil) for an internal combustion engine configured as described above is often mounted on, for example, an engine of an automobile. In this case, the size of the ignition plug hole, the engine locker cover, and the like is severely restricted, and the size of the molded coil has been reduced due to the mounting space.

[0010]

However, in the ignition coil 1A for an internal combustion engine as described above, since the iron core portion 100A itself is large and cannot enter the engine rocker cover 20, the ignition coil 1A is located above the upper end surface 21 of the engine rocker cover 20. However, there is a problem that it is difficult to secure a mounting space.

Further, since the amount of protrusion from the engine locker cover 20 becomes large, there is a problem that a space is taken up in a small engine room.

Further, in recent years, ignition coils for internal combustion engines include:
Higher output is required to be compatible with lean burn engines and alternative fuel engines, and higher output is becoming increasingly important along with the above demand for downsizing.

The present invention has been proposed in order to solve the above-mentioned problems, and the mounting space can be easily secured by downsizing, the space can be saved even in a small engine room, and the output can be increased. It is an object of the present invention to provide a simple ignition coil for an internal combustion engine.

[0014]

Means for Solving the Problems To achieve the above object, an invention according to claim 1 is a cylindrical primary coil bobbin in which a primary coil and a secondary coil are wound and arranged concentrically, respectively. In an ignition coil for an internal combustion engine having a coil bobbin and an iron core forming a closed magnetic path through the inner periphery of the cylinder of the primary coil bobbin and the outer periphery of the secondary coil bobbin, the secondary coil bobbin is circumferentially arranged at a plurality of positions in the longitudinal direction. The ribs are separated by flanges provided in a shape, and each flange portion is divided into winding grooves of the secondary coil, and the flange portion is high at the center of the bobbin, and is gradually lowered toward both sides of the bobbin. .

According to a second aspect of the present invention, in addition to the configuration of the first aspect, when the ignition coil is mounted on an engine, at least a portion extending from an upper end surface of the iron core to the high-pressure tower. The part is mounted in the engine locker cover.

According to a third aspect of the present invention, in addition to the configuration of the first or second aspect of the present invention, the inner peripheral shape of the core portion passing through the outer periphery of the secondary coil bobbin is formed in an arc shape. It is characterized by that.

According to a fourth aspect of the present invention, in addition to the configuration of the first aspect, a permanent magnet is magnetically arranged in series with an iron core forming a closed magnetic circuit. It is characterized by being installed.

[0018]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a view showing a longitudinal section of an ignition coil for an internal combustion engine according to the present invention, and FIG.
3 is an X-ray cross-sectional view, and FIG.

In these figures, an ignition coil 1 for an internal combustion engine comprises a cylindrical primary coil bobbin 2 and a secondary coil bobbin 4 in which a primary coil 3 and a secondary coil 5 are wound and concentrically arranged, respectively. And a core portion 10 forming a closed magnetic path through the inner circumference of the second cylinder and the outer circumference of the secondary coil bobbin 4 (secondary coil 5).

The primary coil bobbin 2 is a tubular member integrally formed of an electrical insulating material such as a synthetic resin, for example, and a primary coil 3 is wound around the outer periphery thereof.

The secondary coil bobbin 4 is disposed concentrically on the outer periphery of the primary coil 3 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 flanges 41 functioning as partitions for winding the secondary coil 5 in a divided manner. That is, the secondary coil bobbin 4 is partitioned by a plurality of flanges 41 provided circumferentially at a plurality of positions in the length direction of the secondary coil bobbin 4.
The space between the windings is a divided winding groove of the secondary coil 5, and the flange portions 41 are higher at the center of the bobbin and gradually lower toward both sides of the bobbin.

On the secondary coil bobbin 4, for example, a secondary coil 5 having a winding ratio of 1:80 to 120 with respect to the primary coil 3 is wound in divided windings with each flange 41 as a partition.

The iron core portion 10 is formed by laminating substantially E-shaped silicon steel sheets and joining the laminated iron cores 11 and 12 with their ends facing each other by means of an adhesive, welding, or the like. A linear root 110 and its root 1
10 has side core portions 111 and 113 extending in an arc shape so as to follow the shape of the secondary coil 5 wound around the secondary coil bobbin 4 from both ends, and a central core portion 112 extending from the center of the root portion 110. ing. The other laminated core 1
2 also has a linear base 120 similar to the laminated core 11.
And the side iron cores 12 extending in an arc shape from both ends of the root 120 along the shape of the secondary coil 5.
1, 123 and a central iron core 122 extending from the center of the root 120.

When the two laminated cores 11 and 12 are joined, the laminated core 11 is attached to the primary coil bobbin 2 from one side.
The central core portion 112 of the laminated core 12 is inserted from the other side, and the end faces facing each other at the center of the bobbin and the end faces facing each other outside the bobbin at this time are bonded by an adhesive or welding as described above. Join. By this joining, as described above, the iron core portion 10 forms a closed magnetic path as a whole through the inner circumference of the cylinder of the primary coil bobbin 2 and the outer circumference of the secondary coil bobbin 4 (secondary coil 5), and forms a magnetic circuit. .

The above-mentioned iron core 10, primary coil 3 and secondary coil 5 are housed in an insulating case 6 molded of an insulating material such as a synthetic resin. A primary terminal seat 61 having a primary terminal 7 is provided on a peripheral wall on one end side of the insulating case 6, and a cylindrical portion 62 for accommodating the high voltage terminal 8 is formed on the other end. An arc-shaped partition wall 15 is erected inside the insulating case 6 so as to surround the outer periphery of the stored secondary coil 5, and is interposed between the secondary coil 5 and the iron core 10. I have.

The primary coil 3 and the primary terminal 7 are electrically connected to each other, and the secondary coil 5 and the high-voltage terminal 8 are electrically connected to each other. The generated high voltage current is supplied to the high voltage terminal 8
Is supplied to the ignition plug 30 via the spring 19, and a spark is generated between the electrodes at the tip.

Then, an insulative thermosetting resin 9 such as an epoxy resin is injected from the opening end of the insulating case 6, whereby the primary coil 3 and the secondary coil 5 inside the insulating case 6 are concentric. The iron core 10 and the like are fixed at predetermined positions.

In the ignition coil 1 for an internal combustion engine having the above structure, the cylindrical portion 62 of the insulating case 6 is housed in the socket 18, and the socket 18 is mounted and fixed on the engine side by the seal portion 22 of the engine locker cover 20. . An ignition plug 30 is housed at the lower end of the socket 18.

As described above, in this embodiment, the secondary coil bobbin 4 is partitioned by the flanges 41 circumferentially provided at a plurality of positions in the length direction of the secondary coil bobbin 4 to divide the secondary coil 5 between the respective flanges 41. The winding groove is used, and its flange 41 is high in the center of the bobbin,
It becomes lower gradually toward both sides of the bobbin. Therefore, the secondary coil bobbin 4 has a drum-like shape with a reduced length, and the iron core portion 10 can also be shortened accordingly. Therefore, the entire ignition coil 1 for an internal combustion engine can be significantly reduced in size. Space for mounting the engine can be easily secured.

Also, due to the miniaturization described above, at least a portion from the upper end surface of the iron core 10 to the cylindrical portion 62 of the insulating case 6 serving as a housing for the high-voltage terminal 8 is mounted on the engine locker cover 2.
Since the ignition coil 1 for the internal combustion engine is configured so that it can be mounted inside and below the internal combustion engine 0, even if the ignition coil 1 for the internal combustion engine is mounted on the engine, the amount of protrusion from the engine rocker cover 20 is small, and the narrow engine It can be installed in a room without taking up space.

Furthermore, since the inner peripheral shape of the iron core portion 10 passing through the outer periphery of the secondary coil bobbin 4 is formed in an arc shape along the shape of the secondary coil bobbin 4, the magnetic circuit length of the magnetic circuit becomes the shortest distance. Since the magnetic resistance decreases and the amount of change in magnetic flux increases, the output as an ignition coil can be improved.

Next, an example in which the output is further improved by the internal combustion engine ignition coil 1 which has been reduced in size and increased in output by the above configuration will be described below as a second embodiment.

FIG. 4 is a cross-sectional view showing the configuration of an ignition coil for an internal combustion engine according to the second embodiment. In the drawings, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. This second
This embodiment differs from the first embodiment in that the permanent magnets 31 and 32 are magnetically arranged in series with the iron core 10 forming a closed magnetic circuit. That is, each end surface of the side core portions 111 and 113 of one laminated core 11 is formed to have an acute angle when viewed from above to increase the area of the end surface, and the other laminated core 12 is opposed to each end surface. Of the side iron core portions 121, 123 are formed, and permanent magnets 31, 32 are interposed between the end surfaces facing each other.

As described above, in the second embodiment, since the permanent magnets 31 and 32 are disposed magnetically in series with the iron core 10, a magnetic reverse bias can be applied to the iron core 10.
As a result, the amount of change in the magnetic flux in the iron core 10 when the primary coil current is interrupted increases, so that the output can be improved.

When the permanent magnets 31 and 32 are arranged in the cylinder of the primary coil bobbin 2, the leakage flux from the permanent magnets 31 and 32 interlinks with the primary coil 3, weakens the magnetic flux of the primary coil 3 and reduces the output. Cause, in this embodiment,
Since the permanent magnets 31 and 32 are arranged outside the secondary coil bobbin 4, a decrease in output due to magnetic flux linkage with the primary coil 3 can be prevented, and the output can be improved from this point as well.

As described above, the present invention has been described based on the embodiments. However, the present invention is not limited to the above-described embodiments. Can also be implemented.

[0037]

Since the present invention has the above-described configuration,
The following effects can be obtained. According to the invention described in claim 1, the secondary coil bobbin is partitioned by flanges provided circumferentially at a plurality of locations in the length direction thereof, and each flange is defined as a divided winding groove of the secondary coil. The height of the bobbin is higher at the center and gradually lower toward both sides of the bobbin, so that the secondary coil bobbin has a shorter drum shape, and the iron core can be shortened accordingly. The entire coil can be significantly reduced in size, and a space for mounting the coil on the engine can be easily secured.

According to the second aspect of the present invention, based on the configuration of the first aspect, at least a portion from the upper end face of the iron core to the high-voltage terminal housing can be mounted in the engine locker cover and below the same. Thus, the amount of protrusion from the engine locker cover can be greatly reduced, and the internal combustion engine ignition coil can be mounted without taking up space even in a small engine room.

Further, according to the third aspect of the present invention, since the inner peripheral shape of the iron core passing through the outer periphery of the secondary coil bobbin is formed in an arc shape along the shape of the secondary coil bobbin, the magnetic circuit length of the magnetic circuit is reduced. At the shortest distance, the magnetic resistance decreases and the amount of change in magnetic flux increases, so that the output as an ignition coil can be improved.

According to the fourth aspect of the present invention, since the permanent magnet is disposed magnetically in series with the iron core portion, a magnetic reverse bias can be applied to the iron core portion. Since the amount of change in the magnetic flux in the iron core is increased, the output can be further improved while the size of the ignition coil for the internal combustion engine is reduced.

[Brief description of the drawings]

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

FIG. 4 is a cross-sectional view illustrating a configuration of an ignition coil for an internal combustion engine according to a second embodiment.

FIG. 5 is a longitudinal sectional view of a conventional ignition coil for an internal combustion engine.

FIG. 6 is a sectional view taken along line YY of FIG. 5;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ignition coil for internal combustion engines 2 Primary coil bobbin 3 Primary coil 4 Secondary coil bobbin 5 Secondary coil 6 Insulating case 7 Primary terminal 8 High voltage terminal 9 Thermosetting resin 10 Iron core 11 Laminated iron core 12 Laminated iron core 15 Partition wall 18 Socket 19 Spring 20 Engine locker cover 21 Upper end surface of engine locker cover 30 Spark plug 31, 32 Permanent magnet 41 Flange 61 Primary terminal seat 62 Tubular part 110, 120 Root part 111, 113 Side core part 121, 123 Side core part 112, 122 Central core Department

Claims (4)

[Claims] 1. A closed magnetic circuit that passes through a cylindrical primary coil bobbin and a secondary coil bobbin in which a primary coil and a secondary coil are wound and disposed concentrically, and an inner circumference of the primary coil bobbin and an outer circumference of the secondary coil bobbin. With the iron core
In the ignition coil for an internal combustion engine having the above, the secondary coil bobbin is partitioned by flanges provided circumferentially at a plurality of locations in the length direction thereof, and between each flange is formed as a divided winding groove of the secondary coil, and the flange is provided. Characterized by being higher at the center of the bobbin and gradually lowering toward both sides of the bobbin. 2. The ignition coil according to claim 1, wherein the ignition coil is mounted on the engine.
An ignition coil for an internal combustion engine, wherein at least a portion from an upper end surface of an iron core portion to a high-voltage terminal storage portion is configured to be mountable in an engine rocker cover. 3. The ignition coil for an internal combustion engine according to claim 1 or 2, wherein an inner peripheral shape of said core portion passing through an outer periphery of said secondary coil bobbin is formed in an arc shape. coil. 4. An ignition coil for an internal combustion engine according to claim 1, wherein a permanent magnet is disposed magnetically in series with an iron core forming a closed magnetic circuit. coil.