JPH0724245B2 - Ignition coil iron core and ignition coil - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an iron core of an ignition coil that stores magnetic energy, and an ignition coil using the iron core.

[Prior Art] An ignition coil is composed of a primary coil, a secondary coil and an iron core. By supplying a current to the primary coil, the iron core is excited and magnetic energy is accumulated, and a current is supplied to the primary coil. Is cut off, the accumulated energy becomes an induced electromotive force to generate a high voltage in the secondary coil, and a spark discharge is generated in the ignition plug connected to the secondary coil.

On the other hand, in recent years, a permanent magnet that repels the magnetic flux of the primary coil is disposed in the magnetic loop of the iron core to increase the amount of accumulated magnetic energy, improve the ignition performance, and reduce the size of the ignition coil.
Lightweight products are disclosed in JP-A-59-167006 and USP45.
It is disclosed in Japanese Patent No. 46753.

[Problems to be Solved by the Invention] On the other hand, in the iron core of the ignition coil, as shown in FIG. 11 and FIG. 12, the primary coil 1 and the secondary coil 2 are wound around the outer periphery of the exciting portion 3, It is composed of a plurality of divided bodies 4, 5. Further, since the permanent magnet 6 is disposed in the magnetic flux loop of the iron core, the air gap 7 for disposing the permanent magnet 6 is formed between the divided bodies 4 and 5.

Then, the primary coil 1 of the ignition coil including the permanent magnet 6
Is energized, a magnetic flux in a direction different from the magnetic flux of the permanent magnet 6 is generated in the exciting unit 3. For this reason, the joint portions of the permanent magnet 6 and the divided bodies 4 and 5 repel each other, and the air gaps 7 tend to separate from each other.

If here, due to the repulsive force of the magnetic flux, it separates from the divided bodies 4, 5, not only the stored energy of magnetism decreases and the ignition performance deteriorates, but also the case of the ignition coil covering the iron core cracks. there is a possibility. If the case of the ignition coil is cracked, the high voltage generated by the secondary coil leaks from the crack of the case, which is very dangerous.

For this reason, the iron core provided with the conventional permanent magnet 6 has been fixed so that the split bodies 4 and 5 do not move by using a non-magnetic bracket or bottle. As a result, the ignition coil is increased in size and weight, and the number of parts is increased, so that the manufacturing cost is increased.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an iron core in which a bracket for fixing the movement of a split body can be eliminated, and to reduce the size and weight using the iron core. The provision of the ignition coil.

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention provides a coil according to claim 1, wherein a primary coil and a secondary coil are wound around the outer circumference.
An exciting part that is excited by energizing the next coil,
It is integrally provided so as to form an annulus, and the exciting part is housed inside the closing part to close the magnetic flux generated by the exciting part and the magnetic flux generated by the exciting part. The technical means comprises a permanent magnet arranged in an air gap between the portion and the closed magnetic circuit forming portion.

In claim 2, a wide head is formed at one end, and a primary coil and a secondary coil are wound around the outer circumference, and an exciting portion that is excited by being transmitted to the primary coil and a U-shaped coil The press-formed products are laminated and integrally provided, and both ends of the exciting part face each other between two opposing sides to close the magnetic flux generated by the exciting part and the closed magnetic circuit forming part and the exciting part. A technical means is provided with a permanent magnet arranged in an air gap between the head of the exciting unit and the closed magnetic path forming unit so as to repel the generated magnetic flux.

According to a third aspect of the present invention, in the iron core of the ignition coil according to the second aspect, the two U-shaped closed magnetic circuit forming portions are joined to each other at both ends of the exciting portion to form a square shape.

The ignition coil according to claim 4 includes a primary coil and a secondary coil.
A secondary coil, an exciting portion having a wide head formed at one end, the primary and secondary coils wound around the outer periphery, and excited by energizing the primary coil, and a press-formed product It has a closed magnetic path forming portion that is laminated and integrally provided, and that houses the exciting portion therein and that both ends of the exciting portion face each other between two opposing sides to close the magnetic flux generated by the exciting portion. Technical means comprising an iron core and a permanent magnet disposed in an air gap between the head of the exciting part and the closed magnetic path forming part so as to repel the magnetic flux generated by the exciting part. And

[Operation] In the iron core of the ignition coil according to the first aspect, since the closed magnetic circuit forming portion is annular and integrally provided, even if a force is applied outward from the inside of the annular closed magnetic circuit forming portion. The closed magnetic circuit forming portion is much less likely to be deformed than a jointed portion without any reinforcement.

For this reason, the exciting part around which the primary coil and the secondary coil are wound around the outer circumference, and the permanent magnet that repels the magnetic flux generated by the exciting part are housed inside to supply current to the primary coil. When a strong repulsive force is generated between each of the permanent magnet and the excitation unit, and between the permanent magnet and the closed magnetic circuit formation unit, the permanent magnetic unit and the excitation unit, and the permanent magnet and closed magnetic circuit There is little or no spread between each of the formations (between the air gaps).

In the iron core of the ignition coil according to the present invention, both ends of the exciting portion are arranged so as to face each other between two opposite sides of the U-shaped closed magnetic circuit forming portion, and the permanent magnet is arranged in the air gap. . That is, the permanent magnet and the exciting portion are sandwiched between the two sides of the U-shaped closed magnetic circuit forming portion. For this reason, even if a repulsive force is generated between the permanent magnet and the exciting portion and between the permanent magnet and the closed magnetic path forming portion, the air gap does not expand due to the strength of the closed magnetic path forming portion itself.

Further, the iron core of the ignition coil described in claim 3 uses two U-shaped closed magnetic circuit forming portions described in claim 2, and the end portions of the closed magnetic circuit forming portions are joined at both ends of the exciting portion. It is formed in a square shape. That is, the permanent magnet and the exciting part are sandwiched between the two sides of each closed magnetic circuit forming part. Therefore, even when a repulsive force is generated between the permanent magnet and the exciting portion and between the permanent magnet and the closed magnetic path forming portion, the air gap is reduced by the strength of the closed magnetic path forming portion itself as in the case of claim 2. It does not spread. Further, the repulsive force is applied between the two sides of each closed magnetic circuit forming portion and does not act on the joint portion of each closed magnetic circuit forming portion. Therefore, the closed magnetic circuit forming portions do not separate from each other due to the repulsive force.

The ignition coil according to claim 4 is provided with an iron core in which both ends of the exciting part are arranged to face each other between two sides of the closed magnetic circuit forming part, and between the head of the exciting part of the iron core and the closed magnetic circuit forming part. A permanent magnet is arranged in the air gap formed in the. Therefore, in the iron core, since the exciting part and the permanent magnet are sandwiched between the two opposite sides of the closed magnetic circuit forming part, the repulsive force is exerted between the permanent magnet and the exciting part and between the permanent magnet and the closed magnetic circuit forming part. The air gap will not widen even if the above occurs.

[Effects of the Invention] In the iron core of the ignition coil according to the present invention, even if a magnetic flux that repels the magnetic flux of the permanent magnet is generated in the exciting portion by energizing the primary coil, the air gap is expanded due to the strength of the closed magnetic circuit forming portion itself. Can be prevented. Therefore, the conventionally used reinforcing bracket can be eliminated.

Also, by eliminating this reinforcing bracket, the ignition coil can be made smaller and lighter, and the manufacturing cost of the ignition coil can be kept low as the number of parts such as the bracket and the mounting bolt is reduced. Become.

[Embodiment] Next, an iron core of an ignition coil of the present invention will be described based on an embodiment shown in the drawings.

1 to 4 show a first embodiment of the present invention, and FIG. 4 shows an example of an electric circuit of an automobile ignition device 100.

An automobile ignition device 100 includes an igniter 200 that generates a non-energized ignition signal when a gasoline engine for vehicle traveling (not shown) is ignited, a primary coil 310 that is switched between energized and non-energized by the igniter 200, and the primary coil. High voltage is generated when 310 is switched from energized state to de-energized 2
Ignition coil 300 with secondary coil 320 and this ignition coil
A spark plug 400 that receives a high voltage from a secondary coil 320 of 300 and generates a spark discharge in an engine combustion chamber (not shown).

In the figure, reference numeral 110 indicates an on-vehicle battery, reference numeral 120 indicates a key switch, and reference numeral 130 indicates a fuse that protects the circuit by fusing.

Next, an ignition coil 300 to which the present invention is applied will be described with reference to the sectional views of FIGS. 1 and 2. Ignition coil 300
Is excited when the primary coil 310 is energized to accumulate magnetic energy, and the primary coil 310 is de-energized to release the magnetic energy accumulated when energized to induce the secondary coil 320. An iron core 500 for generating electromotive force is provided.

The iron core 500 is provided on the inner circumference of the primary coil 310, and includes an independent excitation unit 510 that is excited when the primary coil is energized to generate a magnetic flux. The exciting part 510 is formed by punching a particle-oriented thin plate-shaped magnetic body (for example, soft iron) into a substantially T-shape by a press or the like, and then laminating a plurality of press-formed products and press-crimping them, and one end is wide and flat. It is said to be head 511. Then, the exciting unit 510 includes the primary coil 310.
Is enclosed by an air gap A inside a square-shaped closed magnetic path forming portion 520 which forms a closed magnetic circuit by closing the generated magnetic flux when energized to generate magnetic flux.

Similar to the excitation unit 510, the closed magnetic circuit forming unit 520 is formed by punching a particle-oriented thin plate-shaped magnetic body (for example, soft iron) into a substantially square shape by a press or the like, and then laminating a plurality of press-formed products and press-crimping. , A square-shaped annular portion is integrally provided. In addition, on both sides of the closed magnetic circuit forming portion 520 of the present embodiment,
A ring portion 521 used when attaching the ignition coil 300 to the vehicle is provided.

As shown in FIG. 3, in the air gap A provided between the exciting part 510 and the closed magnetic path forming part 520, the exciting part 510 is adjacent to each other so as to repel the magnetic flux generated by the excitation. A plate-shaped permanent magnet 530 is arranged so that the surfaces thereof have the same pole. The plate-shaped permanent magnet 530 is arranged over the entire width of the head 511 of the exciting unit 510. by this,
The magnetic path cross-sectional area of the permanent magnet 530 can be made sufficiently larger than the magnetic path cross-sectional area of the exciting portion 510 at the portion where the primary coil 310 is wound. The permanent magnet 530 uses a rare earth magnet such as a neodymium magnet or a rare earth-cobalt magnet, and even if it is thin, it generates a large magnetic force.

The primary coil 310 wound around the outer circumference of the exciting part 510 is wound around the outer circumference of an inner circumference bobbin 610 that can house the exciting part 510 therein, and the secondary coil 320 is fitted onto the inner circumference bobbin 610. It is wound around the outer circumference of the outer bobbin 620. Then, by inserting the exciting portion 510 inside the inner peripheral bobbin 610,
A primary coil 310 and a secondary coil 320 are wound around the outer circumference of 510.

The assembled body, in which the primary coil 310 and the secondary coil 320 are mounted on the outer periphery, the excitation unit 510, the closed magnetic circuit forming unit 520, and the permanent magnet 530, is housed in the ignition coil case 700,
Injection resin 710 is injected and cured to form ignition coil 300. The ignition coil case 700 includes a first case 720 having a connector portion 721 connected to the key switch 120 and the igniter 200, and a high voltage terminal 731 connected to a high voltage cord (not shown) connected to the spark plug 400. Second case 730 with
A combination of the first case 720 and the second case 7
Before combining with 30, the electrical connection of each part is done.

Next, the above operation will be described.

When the key switch 120 is turned on, the primary coils 310 and 2
One end of the next coil 320 is connected to the in-vehicle battery 110.
Then, the igniter 200, depending on the operating state of the engine, such as crank angle, rotation speed, load state, cooling water temperature,
An ignition signal is generated so that the primary coil 310 switches from the energized state to the non-energized state at the ignition timing.

When the primary coil 310 is energized, the exciting part 510 of the iron core 500 is excited and the exciting part 510 generates a magnetic flux. This exciter 510
Since the magnetic flux generated by the repulsive force repels the magnetic flux generated by the permanent magnet 530 disposed in the air gap A, the iron core 500 can store a large magnetic energy when energized even if the magnetic flux generated by the primary coil 310 is small. You can

When the primary coil 310 is switched to the non-energized state by the igniter 200 at the ignition timing, the magnetic energy stored in the iron core 500 is released and the secondary coil 320 wound around the outer periphery of the iron core 500 is induced. Electricity is generated. Secondary coil 3
Since 20 is thinner than the primary coil 310 and is wound around the outer periphery of the exciting part 510 in large numbers, a high voltage is generated in the secondary coil 320 due to the induced electromotive force. Then, the high voltage generated in the secondary coil 320 is applied to the spark plug 400,
Spark discharge is generated in the engine combustion chamber.

Then, the igniter 200 energizes the primary coil 310 again,
Repeat the above.

On the other hand, when the primary coil 310 is energized and the exciting part 510 generates a magnetic flux, the magnetic flux generated by the exciting part 510 repels the magnetic flux generated by the permanent magnet 530, and as shown in FIG. Due to the repulsive force, the space between 530 and the excitation unit 510 and the space between the permanent magnet 530 and the closed magnetic circuit formation unit 520 tend to separate from each other.

However, since the closed magnetic path forming portion 520 is annular and is integrally provided, even if a force is applied from the inside of the closed magnetic path forming portion 520 toward the outside, the closed magnetic path forming portion 520 does not need any reinforcement. , Much less likely to be deformed than the one with seams. Therefore, the exciting portion 510 is excited, and the permanent magnet 530 and the exciting portion 510 and the permanent magnet 530 and the closed magnetic path forming portion 520 (between the air gaps A) try to separate from each other due to the repulsive force. However, since the closed magnetic path forming portion 520 does not deform, it does not expand between the air gaps.

That is, according to this embodiment, even if a current is supplied to the primary coil 310 and a force that expands the air gap A due to the repulsion of the magnetic flux is applied, the air gap A expands due to the strength of the closed magnetic path forming portion 520 itself. I don't get it. Therefore, it is possible to eliminate the reinforcing bracket that has been used to prevent the air gap from expanding.

And by abolishing this reinforcing bracket,
The ignition coil 300 can be made smaller and lighter than conventional ones, and the manufacturing cost of the ignition coil 300 can be kept low by reducing the number of parts such as brackets and mounting bolts.

Further, since the conventional iron core has one magnetic flux loop (because of the I-shaped exciting portion and the U-shaped exciting path forming portion, which is ring-shaped and has one magnetic path), a closed magnetic path is formed. There is a magnetic flux path with a small magnetic resistance passing through the inner circumference of the part and a magnetic flux path with a large magnetic resistance passing through the outer circumference, the rate of change of the magnetic path becomes large, and the conversion efficiency between magnetic energy and electromotive force deteriorates. There was a problem that would end up.

However, in this embodiment, when the primary coil 310 is energized and the exciting part 510 is excited, the magnetic flux generated by the exciting part 510 is divided into two magnetic paths by the annular closed magnetic path forming part 520 and flows. . For this reason, the rate of change of the magnetic path is smaller than that of the conventional iron core having only one magnetic flux loop, and the conversion efficiency between magnetic energy and electromotive force can be improved as compared with the conventional one. The coil 300 can be downsized.

FIG. 5 shows a second embodiment of the present invention.

In the above embodiment, the exciting portion 510 is provided in a substantially T shape, and the width of the head portion 511 is increased to make the magnetic path sectional area of the permanent magnet 530 sufficiently larger than the magnetic path sectional area of the exciting portion 510. Although the magnetic force of 530 is increased, the iron core 5 shown in this embodiment is
00 is an example in which the exciting portion 510 is provided in a substantially L shape and the width of the head portion 511 is large.

A third embodiment of the present invention is shown in FIGS. 6 and 7.

In the above embodiment, an example in which the stacking direction of the exciting part 510 and the stacking direction of the closed magnetic path forming part 520 are provided in the same direction, that is, in parallel, is shown. It is orthogonal to the stacking direction of the path forming portion 520.

FIG. 8 shows a fourth embodiment of the present invention.

In the above-mentioned embodiment, the closed magnetic circuit forming portion 520 is formed by integrally laminating press-shaped press-formed products, but in the present embodiment, the closed magnetic circuit forming portion 520 is formed by stacking U-shaped press-formed products. The two divided bodies 522 and 523 are integrated by driving, welding or the like so as to be joined at both ends of the exciting part 510.

A closed magnetic circuit forming portion 520 composed of these two divided bodies 522 and 523.
Is the exciting part 51 between the two sides of the divided bodies 522, 523 extending in parallel.
Both end faces of 0 are arranged so as to face each other, and the head 511 of the excitation unit 510 is
A permanent magnet 530 is arranged in an air gap A formed between the and. That is, since the exciting part 510 and the permanent magnet 530 are sandwiched between the two parallel sides of each of the divided bodies 522 and 523, even if a repulsive force is applied between the air gaps A as the primary coil 310 is energized. The air gap A never expands. In addition, the closed magnetic circuit forming portion 520 includes two divided bodies 522,
Since 523 is joined at both ends of the excitation part 510 in a direction toward each other (vertical direction in FIG. 8), the joined part does not separate even if a repulsive force is applied between the air gaps A.

FIG. 9 shows a fifth embodiment of the present invention.

In this embodiment, two semi-cylindrical cores 52 having hollow interiors are used.
The closed magnetic circuit forming portion 520 is formed by joining 4, 525 together.

As a result, the rate of change of the magnetic path becomes smaller than that in the above-mentioned embodiment, so that the conversion efficiency between magnetic energy and electromotive force can be further improved, and the ignition coil 300 can be further downsized. Becomes The two semi-cylindrical cores 524 and 525 are provided with holes (not shown) for connecting the primary coil 310 and the secondary coil 320 to the outside.

FIG. 10 shows a sixth embodiment of the present invention.

In this embodiment, the lateral length (horizontal direction in FIG. 10) W and the vertical length (vertical direction in FIG. 10) of the closed magnetic circuit forming portion 520 which is the longitudinal direction of the exciting portion 510 shown in the first embodiment. Direction) L and W
It was set such that <L.

By setting the closed magnetic path forming portion 520 to have such a dimensional ratio, the closed magnetic path forming portion 52 is formed from a thin plate-shaped magnetic body (for example, soft iron).
When pressing 0, as shown in FIG. 10, the inner portion of the closed magnetic circuit forming portion 520 can be used to press the excitation portion 510 at the same time as the closed magnetic circuit forming portion 520.

It should be noted that FIG. 10 shows the closed magnetic circuit forming portion 520 when the press is removed.
3 shows the arrangement of the magnetic field and the excitation unit 510.

As shown in the first embodiment, when the closed magnetic path forming portion 520 is punched into a square shape in order to suppress the repulsive force of the permanent magnet 530, the inner portion of the closed magnetic path forming portion 520 becomes scrap. , Yield gets worse. Therefore, as in the present embodiment, the yield of the iron core 500 can be improved by using the inner portion of the closed magnetic circuit forming portion 520 to press the exciting portion 510.

[Brief description of drawings]

1 to 4 show a first embodiment of the present invention. FIG. 1 is a front sectional view of an ignition coil, FIG. 2 is a side sectional view of the ignition coil, and FIG. 3 is a sectional view of FIG. Partial sectional view, 4th
FIG. 5 is an electric circuit diagram of an automobile ignition device, FIG. 5 is a plan view of an iron core showing a second embodiment of the present invention, and FIG. 6 is a third view of the present invention.
FIG. 7 is a plan view of an iron core showing an embodiment, FIG. 7 is a sectional view taken along the line II of FIG. 6, FIG. 8 is a plan view of the iron core showing a fourth embodiment of the present invention, and FIG. 9 is the present invention. 10 is a partial sectional view of an ignition coil showing a fifth embodiment of the present invention, FIG. 10 is a layout view of an iron core when a press is removed showing a sixth embodiment of the present invention, and FIGS. 11 and 12 are perspective views showing a conventional iron core. It is a figure and a top view. In the figure, 300 ... Ignition coil, 310 ... Primary coil, 320 ...
… Secondary coil, 500 …… Iron core, 510 …… Excitation part, 520 ……
Closed magnetic circuit forming part, 530 ... Permanent magnet

Claims (4)

[Claims] 1. A primary coil and a secondary coil are wound around an outer periphery, and are integrally provided in an annular shape with an exciting portion that is excited when the primary coil is energized. A closed magnetic path forming portion that houses an exciting portion and closes the magnetic flux generated by the exciting portion, and an air gap between the exciting portion and the closed magnetic path forming portion that repels the magnetic flux generated by the exciting portion. An iron core of an ignition coil having a permanent magnet arranged therein. 2. An exciting portion having a wide head formed at one end and having primary and secondary coils wound around an outer periphery thereof and being excited by energizing the primary coil, and a U-shaped press. Molded products are laminated and integrally provided, and both ends of the exciting part face each other between two opposing sides to close a magnetic flux generated by the exciting part, and a closed magnetic path forming part, and the exciting part is generated. An iron core of an ignition coil, comprising: a permanent magnet arranged in an air gap between the head of the exciting unit and the closed magnetic circuit forming unit so as to repel the magnetic flux generated by the magnet. 3. The iron core of an ignition coil according to claim 2, wherein the two U-shaped closed magnetic circuit forming portions are joined to each other at both ends of the exciting portion to form a square shape. 4. A primary coil, a secondary coil, and a wide head formed at one end, the primary and secondary coils being wound around an outer periphery, and the primary coil being energized. An exciting part to be excited and a press-molded product are laminated and provided integrally, and the exciting part is housed inside thereof.
An iron core having both ends of the exciting part facing each other between two opposite sides and a closed magnetic path forming part for closing the magnetic flux generated by the exciting part, and the exciting part so as to repel the magnetic flux generated by the exciting part. An ignition coil comprising: a permanent magnet disposed in an air gap between the head of the head and the closed magnetic circuit forming portion.