JPH09148154A - Ignition coil and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to insert an ignition coil in a plug hole without enlarging the dimension of the plug hole by a method wherein a magnetic core, a primary coil, a secondary winding floor and a secondary coil are housed in a case. SOLUTION: An electric wire 3a is directly wound on the surface of a magnetic core 1 to form a primary coil 3 and a secondary coil 5 is formed by winding an electric wire 5a on the surface of a roughly cylindrical secondary winding floor 4. The coil 3 is inserted in a cylindrical hole formed in the winding floor 4 and the magnetic core 1, the coil 3, the winding floor 4 and the coil 5 ate housed in a case A2. After that, the interior of the case A2 is sealed by injecting a resin 8 in the case A2. Here, the magnetic core 1 is constituted by winding closely an amorphous alloy foil 1b, such as an Fe-Si-B alloy foil, around the axial core of an electromagnetic soft iron rod (a metal core rod) 1a into a roll form.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ignition coil for an independent ignition system used in an internal combustion engine and a method for manufacturing the ignition coil.

[0002]

2. Description of the Related Art As shown in FIG. 7, an ignition coil of this type includes a magnetic core 21 in which electromagnetic steel plates are laminated, a primary winding bed 22 mounted on the magnetic core 21, and a primary winding floor 22. A primary coil 23 formed by winding an enameled wire as a primary winding, a secondary winding floor 24 fitted on the outside of the primary winding floor 22 on which the primary coil 23 is formed, and this secondary An ignition coil main body 26 is formed by a secondary coil 25 formed by winding an enameled wire as a secondary winding on the side winding bed 24, and the ignition coil main body 26 is housed in a case 27. It is composed by.

Further, the space of the case 27 in which the ignition coil body 26 is housed is filled with a thermosetting resin such as epoxy resin by vacuum injection, and the thermosetting resin is used for the primary coil 23 and the secondary coil. 25 and 25 are impregnated and fixed to each other, and the insulation that withstands the high output voltage of the secondary coil 25 is ensured.

In the ignition coil constructed as described above, only the connector part (not shown) on the secondary side is inserted into a predetermined plug hole of the internal combustion engine, and the case 27 and the like project above the internal combustion engine. The primary side is connected to the battery via a cable, and the secondary side is connected to a predetermined spark plug in the plug hole.

[0005]

By the way, these independent ignition type ignition coils are installed between the components laid out on the upper surface side of the internal combustion engine because the case 27 and the like are mounted so as to project from the upper surface of the internal combustion engine. The problems around the space were constant.

Therefore, recently, as a countermeasure, there has been an attempt to install all of the ignition coil case 27 and the like in the plug hole, but with the conventional ignition coil size,
It was difficult to insert the whole into the plug hole.

If the diameter of the plug hole is increased, it is possible to insert the conventional ignition coil into the internal combustion engine. However, when a narrow-angle valve such as a 4-valve type is used, if the diameter of the plug hole is enlarged, it is unavoidable to change the mounting angle of the valve around it. Then, characteristics such as fuel consumption and horsepower are deteriorated, which is inconvenient.

In view of the above problems, it is an object of the present invention to provide an ignition coil which can be fitted in the plug hole without enlarging the diameter of the plug hole, and a manufacturing method thereof.

[0009]

Means for solving the problems are as follows. A magnetic core formed of a ferromagnetic material, and a primary wire formed by directly winding an electric wire on the surface of the magnetic core. A coil, an insulative secondary winding bed arranged on the outer periphery of the primary coil, a secondary coil formed by winding an electric wire on the surface of the secondary winding bed, and the magnetic A core, the primary coil, the secondary winding bed, and a case that houses the secondary coil.

In such a structure, since the primary winding bed which has been conventionally used is omitted, the diameter can be reduced as a whole by the thickness of the primary winding bed. In particular, when the diameter is made smaller than the diameter of the plug hole, the whole can be inserted into the plug hole. Therefore, the degree of freedom in designing the upper surface side of the internal combustion engine can be increased as compared to the conventional case in which the upper surface side of the internal combustion engine is mounted so as to project. At this time, since it is not necessary to increase the diameter of the plug hole, it is possible to prevent a situation in which the mounting angle of the valve around the plug hole is changed and characteristics such as fuel consumption and horsepower are deteriorated. In addition, since the primary winding bed is omitted, the cost of the molded product including the mold can be omitted, and the number of parts and man-hours can be reduced. Therefore, the cost as a whole can be reduced.

Further, if the primary winding is wound directly around the magnetic core, the apparent magnetic permeability becomes large as the magnetic core approaches the magnetic core, as compared with the conventional one using the primary winding bed. The lines of magnetic force generated in step 2 are efficiently stored in the magnetic core. Therefore, the output energy of the secondary coil is improved.

Preferably, the magnetic core is a composite of a metal core rod (for example, an electromagnetic soft iron rod) made of a ferromagnetic material and an amorphous alloy foil wound around the outer periphery of the metal core rod in a roll shape.

In such a structure, the amorphous alloy foil is
The cross-sectional area of the magnetic core required to obtain the same inductance can be reduced as compared with the magnetic core including only the electromagnetic rope and the like, and the diameter of the magnetic core can be reduced accordingly. Therefore, it is possible to further reduce the diameter as a whole.

When manufacturing the ignition coil, first, the wire is wound directly on the surface of the magnetic core to form a primary coil, and the wire is wound on the surface of the substantially cylindrical secondary winding bed. A secondary coil is formed by winding. And
By inserting the primary coil in the cylindrical hole of the secondary winding bed,
After housing the magnetic core, the primary coil, the secondary winding bed, and the secondary coil in a case, the inside of the case is sealed by resin injection.

Thus, even if the electric wire is directly wound on the surface of the magnetic core as the primary coil portion, the ignition coil can be easily manufactured and the electric wire can be easily prevented from being unwound thereafter.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The ignition coil according to the embodiment of the present invention depends on the thickness of the primary winding bed by directly winding the primary winding without attaching the winding bed (bobbin) to the magnetic core. This is to prevent the coil diameter from increasing. FIG. 1 is a sectional view showing an ignition coil according to this embodiment. As shown in FIG. 1, the ignition coil includes a coil mechanism portion A1 and a case A2 in which the coil mechanism portion A1 is housed.

The coil mechanism portion A1 has a magnetic core 1 as a magnetic body, and an enameled wire 3a as a primary winding on the magnetic core 1.
Primary coil 3 formed by directly winding
And the secondary winding bed 4 fitted on the outside of the primary coil 3.
And a secondary coil 5 formed by winding an enamel wire 5a as a secondary winding on the secondary winding bed 4.
And.

The magnetic core 1 is made of an Fe-Si-B type amorphous alloy foil 1b having a relative magnetic permeability that is relatively larger than that of an electromagnetic steel plate, for example, a thickness of 25 .mu.m. Core rod) 1a is formed by closely winding it in a roll shape around its axis, and its diameter is 10 mm.
It is considered as a degree. Further, the enamel wire 3a, which is the primary winding, has a diameter in which a polyesterimide layer, a polyamideimide layer, and a high heat-resistant fusion-bonding layer such as an epoxy resin or a polyamide resin are sequentially laminated on the outer periphery of a core wire portion made of copper or the like. The one having a size of 0.4 to 0.6 mm is used, and is wound around the magnetic core 1 about 150 times.

The secondary winding bed 4 is formed by molding using an insulating organic material such as modified polyphenylene oxide or polybutylene terephthalate, and is used to insert the primary coil 3 in the center. The fitting insertion hole (cylindrical hole) 4a is formed. In addition, the outer surface of the secondary winding bed 4 has a plurality of flange portions 4b that radially extend at regular intervals, and the enamel wire 5a is section-wound between the flange portions 4b. The enamel wire 5a, which is the secondary winding, has a diameter of 0.03 to 0.07 mm, for example.

In the space of the case A2 in which the coil mechanism portion A1 is housed, a thermosetting resin 8 such as epoxy resin is used.
The (fixing means) is filled by vacuum injection, and the thermosetting resin 8 impregnates and fixes the primary coil 3 and the secondary coil 5 to each other and secures the insulating property to withstand the high output voltage of the secondary coil 5. It is supposed to be done.

As shown in FIG. 2, the case A2 has a primary connector portion 12 having a primary side connecting terminal to which the primary coil 3 is connected and a secondary connector terminal 12 having a secondary side connecting terminal to which the secondary coil 5 is connected. The next connector portion 14 is attached. A surface portion of the primary connector portion 12 is covered with a protective member (rain cover) made of an insulating material, and a connection terminal (not shown) therein is connected to a battery portion (not shown) via a switch portion 15 and a primary side lead wire 16. To be done. On the other hand, the surface portion of the secondary connector portion 14 is covered with a rubber bush, and is fitted into the connector portion 17 of the ignition plug arranged in the inner portion of the plug hole 19. The diameter Rw of the entire ignition coil having such a configuration is set to about 22 mm or less.

The ignition coil thus constructed is manufactured as follows. First, in the first step, the Fe-Si-B system amorphous alloy foil 1b is wound around the surface of the electromagnetic soft iron rod 1a to form the magnetic core 1 having a diameter of about 10 mm as shown in FIG. Then, in the second step, the enameled wire 3a is directly horizontally wound around the surface of the magnetic core 1 about 150 times by a predetermined primary coil winding device to form the primary coil 3, as shown in FIG.

On the other hand, as shown in FIG. 5, in the third step, the secondary winding bed 4 is formed by molding using an insulating organic material such as modified polyphenylene oxide or polybutylene terephthalate. deep. On this occasion,
A fitting insertion hole 4a for fitting and inserting the primary coil 3 is formed in the center of the secondary winding bed 4, and the secondary winding bed 4 is also provided.
A plurality of flange portions 4b are formed on the outer surface of the above so as to extend in the radial direction at regular intervals. Further, in the fourth step, the enamel wire 5a is section-wound by a predetermined secondary coil winding device between the collar portions 4b of the secondary winding bed 4, and the secondary winding on the surface of the secondary winding bed 4 is performed. The coil 5 is formed.

Then, in the fifth step, as shown in FIG.
The magnetic core 1 in which the primary coil 3 is formed is fitted into the fitting hole 4a of the secondary winding bed 4 and is referred to as a coil mechanism portion A1. In the sixth step, the coil mechanism A1 is set to have an outer diameter of 22 mm.
It is housed in the following case A2. Then, in the seventh step, as shown in FIG. 1, the thermosetting resin 8 is vacuum-injected and thermoset in an oven, and the thermosetting resin 8 impregnates and fixes the primary coil 3 and the secondary coil 5 to each other. In addition, the insulation that withstands the high output voltage of the secondary coil 5 is ensured.

When the ignition coil manufactured as described above is attached to the internal combustion engine, the primary connector portion 12 and the secondary connector portion 14 are first attached at predetermined positions as shown in FIG. Then, the switch portion 15 and the primary side lead wire 1 are connected to unillustrated connection terminals inside the primary connector portion 12.
By connecting 6 to the battery unit (not shown). Then, the case A2 is housed in the plug hole 19 of the internal combustion engine E1, and the secondary connector portion 14 is fitted to the connector portion 17 of the spark plug arranged in the inner portion.

As described above, in this embodiment, since the primary side winding bed which has been conventionally present in the primary coil 3 is omitted, it is possible to reduce the diameter as a whole by the thickness of the primary side winding bed. The case A2 can be inserted without changing the diameter of the plug hole 19. Therefore, the degree of freedom in designing the upper surface side of the internal combustion engine E1 can be increased without changing the mounting angle of the valves around the valve and deteriorating the characteristics such as fuel consumption and horsepower.

Further, since the primary winding bed can be omitted, the cost of the molded product including the mold can be omitted, and the number of parts and man-hours can be reduced. Therefore, the cost as a whole can be reduced.

Here, it is known that when there is an air gap between the primary winding and the magnetic core as in the prior art, the magnetic permeability is reduced by the amount of the air gap, but in this embodiment, If the enamel wire 3a as the primary winding is wound directly around the magnetic core 1 as described above, the apparent magnetic permeability becomes larger as the magnetic core 1 is approached than when the primary winding bed is used. The magnetic lines of force generated in the primary coil 3 are efficiently accommodated in the magnetic core 1, and the so-called magnetic coupling degree is improved. Therefore, the output energy of the secondary coil 5 is improved.

In the above embodiment, the magnetic core 1 is formed by winding an amorphous alloy foil around an electromagnetic soft iron rod. However, the magnetic core 1 is not limited to this structure. For example, a plurality of wire rods may be bundled by a binding device. A bundle may be applied.

The enamel wire 3a which is the primary winding
Was formed by sequentially stacking a polyesterimide layer, a polyamideimide layer, and an epoxy resin, a high heat-resistant fusion-bonding layer such as a polyamide resin on the outer periphery of the core made of copper or the like,
Any material may be used as long as it has a highly heat-resistant insulating organic film.

Further, in the above embodiment, the fitting insertion hole 4a is used.
After winding the enamel wire 5a around the secondary winding bed 4 having
Although the magnetic core 1 and the primary coil 3 were inserted into the insertion hole 4a, the magnetic core 1 and the primary coil 3 were extruded and coated with an insulating organic material to form a secondary winding bed. The coil mechanism portion A1 may be formed by winding an enameled wire as a secondary winding on the secondary winding bed.

[0032]

As described above, according to the ignition coil of the present invention, since the primary winding bed which has been conventionally used is omitted, the diameter of the entire primary winding bed can be reduced by the thickness of the primary winding bed. You can In particular, when the diameter is made smaller than the diameter of the plug hole, the whole can be inserted into the plug hole. Therefore, the degree of freedom in designing the upper surface side of the internal combustion engine can be increased as compared to the conventional case in which the upper surface side of the internal combustion engine is mounted so as to project. At this time, since it is not necessary to increase the diameter of the plug hole, it is possible to prevent a situation in which the mounting angle of the valve around the plug hole is changed and characteristics such as fuel consumption and horsepower are deteriorated. In addition, since the primary winding bed is omitted, the cost of the molded product including the mold can be omitted, and the number of parts and man-hours can be reduced. Therefore, the cost as a whole can be reduced.

Further, if the primary winding is wound directly around the magnetic core, the apparent magnetic permeability becomes larger as the magnetic core approaches the magnetic core than in the conventional case using the primary winding bed. The generated magnetic force lines are efficiently accommodated in the magnetic core. Therefore, the output energy of the secondary coil is improved.

When the magnetic core is composed of a composite of a metal core rod made of a ferromagnetic material (for example, an electromagnetic soft iron rod) and an amorphous alloy foil wound in a roll around the outer periphery of the metal core rod, Amorphous alloy foil can reduce the cross-sectional area of the magnetic core required to obtain the same inductance as compared with the magnetic core consisting only of electromagnetic steel plates, etc., and the diameter of the magnetic core can be reduced accordingly. You can Therefore, the overall diameter can be further reduced.

When the ignition coil is manufactured, first, the electric wire is directly wound on the surface of the magnetic core to form the primary coil, and the electric wire is placed on the surface of the substantially cylindrical secondary winding bed. Since the secondary coil is formed by winding,
Even if the electric wire is directly wound on the surface of the magnetic core as the primary coil portion, the ignition coil can be easily manufactured. Then, after inserting the primary coil into the cylinder hole of the secondary winding bed to house the magnetic core, the primary coil, the secondary winding bed and the secondary coil in the case, resin is injected into the case to seal it. Since it is stopped, it is possible to easily prevent the electric wire from collapsing after that.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an ignition coil according to an embodiment of the present invention.

FIG. 2 is a diagram showing a state in which the ignition coil according to the embodiment of the present invention is mounted in a plug hole.

FIG. 3 is a diagram showing a manufacturing process of the ignition coil according to the embodiment of the present invention.

FIG. 4 is a diagram showing a manufacturing process of the ignition coil according to the embodiment of the present invention.

FIG. 5 is a diagram showing a manufacturing process of the ignition coil according to the embodiment of the present invention.

FIG. 6 is a diagram showing a manufacturing process of the ignition coil according to the embodiment of the present invention.

FIG. 7 is a cross-sectional view showing a conventional ignition coil.

[Explanation of symbols]

 A1 Coil mechanism part A2 Case 1 Magnetic core 3 Primary coil 3a Enamel wire 4 Secondary side winding bed 4a Fitting hole 4b Collar part 5 Secondary coil 5a Enamel wire 8 Thermosetting resin 12 Primary connector part 14 Secondary connector part

Claims (4)

[Claims] 1. A magnetic core formed of a ferromagnetic material, a primary coil formed by directly winding an electric wire on a surface of the magnetic core, and an insulation arranged on an outer peripheral portion of the primary coil. Secondary winding bed, a secondary coil formed by winding an electric wire on the surface of the secondary winding bed, the magnetic core, the primary coil, the secondary winding bed and the An ignition coil, comprising: a case that houses the secondary coil. 2. The ignition coil according to claim 1, wherein:
An ignition coil, wherein the magnetic core comprises a composite of a metal core rod made of a ferromagnetic material and an amorphous alloy foil wound around the outer periphery of the metal core rod in a roll shape. 3. The ignition coil according to claim 2, wherein:
The ignition coil, wherein the metal core rod is an electromagnetic soft iron rod. 4. The method of manufacturing an ignition coil according to claim 1, wherein a step of directly winding an electric wire on a surface of a magnetic core to form a primary coil, and a substantially cylindrical secondary winding bed. A step of forming a secondary coil by winding an electric wire on the surface of, a step of inserting the primary coil in a cylindrical hole of the secondary winding bed, the magnetic core, the primary coil, the A method for manufacturing an ignition coil, comprising: a step of housing a secondary winding bed and the secondary coil in a case; and a step of sealing the inside of the case with resin injection.