JPH0897057A - Ignition coil - Google Patents

Abstract

PURPOSE: To enable an iron core and a magnet to from a magnetic path built in an ignition coil and to be surely held and fixed in a simple constitution. CONSTITUTION: An ignition coil is equipped with a thin cylindrical case which is housed in a plug tube provided to an engine, and a transformer is contained in the case and immersed in insulating oil. The transformer is equipped with a secondary spool 510 and a primary spool 514, and an iron core and a magnet are pinched between the base 510a of the secondary spool 510 and the top 514a of the primary spool 514. The iron core and the magnet are preliminarily fastened with an adhesive tape 31 and then contained in the spools 510 and 514. By this constitution, an iron core and a magnet are capable of being surely held and fixed in a simple constitution, so that an ignition coil can be simplified in an assembly process.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an ignition coil for supplying a high voltage to an ignition plug of an internal combustion engine.

[0002]

2. Description of the Related Art Many conventional ignition coils have a structure in which an iron core is provided at the center and a primary coil and a secondary coil are coaxially provided on the outer periphery thereof. In addition, the iron core is generally a closed magnetic circuit in order to prevent leakage of magnetic flux, and a partial air gap may be formed if necessary.
A part of the magnetic path is constructed by a magnet. As such an ignition coil, various shapes are known, such as one mounted on a vehicle body, one mounted on an engine, and one mounted directly on an ignition plug of an engine.

For example, Japanese Unexamined Patent Publication No. 3-154311 discloses a thin cylindrical ignition coil which can be mounted in a plug tube provided from the outer shell of an engine toward a spark plug mounting hole.

[0004]

The above-mentioned prior art discloses the one in which a part of the magnetic path is constituted by a magnet. However, since the magnetic path is constituted by a plurality of members including the magnet, it is complicated. Various assembly work was required. Therefore, the present invention is
An object of the present invention is to provide an ignition coil which is easy to assemble even when the magnetic path is composed of a plurality of members and which can surely hold the plurality of magnetic path constituent members.

[0005]

In order to achieve the above object, according to the present invention, a rod-shaped magnetic path forming member for passing magnetic flux, a spool provided on the outer periphery of the magnetic path forming member, and a coil held by the spool. And an ignition coil including the magnetic path forming member, the spool, and a case accommodating the coil, wherein the magnetic path forming member is configured by connecting a plurality of members in an axial direction, and the magnetic path forming member. A technical means called an ignition coil is adopted in which a plurality of members are sandwiched by a plurality of parts assembled along the axial direction of the magnetic path forming member.

The case is formed in a tubular shape, and at one end of the case is provided a connecting portion with an ignition plug.
A storage chamber may be formed in which a conductive member that is electrically connected to the connection portion is exposed at the bottom, and the spool, the coil, and the magnetic path forming member are stored in the storage chamber.
The spool has first and second cylindrical spools that are multiply provided on the outer periphery of the magnetic path forming member.
The coil has a primary coil held by the first spool and a secondary coil held by the second spool, and the first spool is one axial end of the magnetic path forming member. Side, the second spool is in contact with the other axial end of the magnetic path forming member, and together with the closing part of the first spool, a plurality of members of the magnetic path forming member are provided. It may be configured to include a closing portion for sandwiching. The closing portion of the present invention does not have to realize complete closing, and may have any shape as long as it can come into contact with and support the axial end portion of the magnetic path forming member.

The second spool is accommodated in the accommodating chamber with the closing portion facing the bottom of the accommodating chamber, and the closing portion has a spool-side conductive member that comes into contact with a conductive member exposed at the bottom portion. It is desirable that a member is provided and configured. Further, the spool has a closing portion that comes into contact with one end side of the magnetic path forming member in the axial direction, and the case has a lid portion that is assembled from the axial direction of the magnetic path forming member. May be configured to include an abutting portion that abuts on the other end side of the magnetic path forming member in the axial direction and that holds a plurality of members of the magnetic path forming member together with the closing portion of the spool.

The spool is accommodated in the accommodating chamber with the closing portion facing the bottom of the accommodating chamber, and the closing portion is provided with a spool-side conductive member that comes into contact with the conductive member exposed at the bottom. It is desirable to be configured as a single unit. Further, the magnetic path constituent member may be composed of a rod-shaped iron core and two magnets provided at both ends of the iron core.

Further, it is preferable that insulating oil is injected into the case and the coil is immersed in the insulating oil. Further, in order to achieve the above-mentioned object, in the present invention, in an ignition coil that supplies a high voltage to an ignition plug of an internal combustion engine, a case that is formed in a tubular shape and forms a storage chamber, and a tube whose one end side is closed by a closing portion. Formed into a
A secondary spool housed in the housing chamber, a secondary coil held by the secondary spool, and a tubular shape that is closed at one end side by a closing portion, and the closing portion is an open end of the secondary spool. A primary spool that is located on the side and is provided coaxially with the secondary spool and that is housed in the housing chamber;
A primary coil held by the primary spool, a cylindrical auxiliary core having a notch provided in the outer periphery of the secondary spool and the primary spool, and injected into the accommodating chamber, at least the primary coil and the secondary coil. Insulating oil in which the coil is dipped, and a rod-shaped iron core sandwiched between the closing portion of the secondary spool and the closing portion of the primary spool,
And a technical means called an ignition coil which is provided with magnets provided at both ends of the iron core.

A control circuit section may be housed in the case.

[0011]

According to the present invention described above, since a plurality of members of the magnetic path forming member are sandwiched by a plurality of parts assembled along the axial direction thereof, the magnetic path forming member connected in the axial direction The connection is reliably maintained with a simple structure. It should be noted that it is desirable to use a first spool as a primary spool and a second spool as a secondary spool as parts for sandwiching the magnetic path constituting member. It is possible to reliably sandwich the constituent members.

Further, the magnetic path forming member may be sandwiched between the spool and the lid of the case. Furthermore, it is desirable to hold a conductive member for connecting the high voltage generated in the secondary coil to the spark plug in the closed portion provided on the spool,
As a result, electrical conduction can be obtained simply by housing the spool in the case. Further, it is desirable that the coil in the case is immersed in insulating oil, and by using the insulating oil, high insulating property can be obtained for a long period of time even with a narrow insulating distance.

According to another aspect of the present invention, since the iron core and the magnets provided at both ends of the iron core are sandwiched between the primary spool and the secondary spool, the iron core and the magnet are securely held and fixed with a simple structure. .

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an ignition coil to which the present invention is applied will be described below with reference to the drawings. 1 and 2 are vertical sectional views of an ignition coil according to the first embodiment. 1 shows the upper portion of the ignition coil and FIG. 2 shows the lower portion of the ignition coil.
Both figures are connected by the line I-I and the line II-II to form an overall view of the ignition coil.

The first embodiment is disclosed in JP-A-3-154311.
Like the ignition coil disclosed in No. 1, it is formed into a thin cylindrical shape that can be installed in the plug tube of the engine and is directly connected to the ignition plug installed in the engine and fixed directly to the engine head cover or cylinder head. To be done. First, the configuration of the ignition coil 1 will be described.

The case 100 of the ignition coil 1 is formed of a resin material in a cylindrical shape, a connecting portion 3 for connecting to an ignition plug is provided at its lower end, and a housing chamber 102 in the case 100 is provided. A transformer section 5 for high voltage generation and a control circuit section 7 for connecting and disconnecting the primary current thereof are accommodated, and a control signal input connector 9 and a fixing bracket 11 are provided at an upper end portion.
And are provided.

A tubular portion 104 for accommodating an ignition plug is formed in the connecting portion 3 by the case 100, and a rubber plug cap 13 is attached to the opening end thereof. A metal cup 15 serving as a conductive member is insert-molded in the resin material of the case 100 on the bottommost inner surfaces of the accommodation chamber 102 and the tubular portion 104, and the accommodation chamber 102 and the tubular portion 104 are connected to each other. The space is partitioned liquid-tight. Cup 15
Has a slightly larger bottom diameter, and one large diameter portion of the spring 17 is locked to the bottom. The other end of the spring 17 is formed in a spiral shape in the plane of the end portion thereof, and when the spark plug is housed in the tubular portion 104, the terminal comes into contact with the terminal in a conductive manner.

The bottom of the storage chamber 102 is closed by the cup 15, and the stepped portion 10 is formed around the exposed portion of the cup 15.
Have six. A connector housing of the control signal input connector 9 is formed integrally with the case 100, and three connector pins 19 are insert-molded to penetrate the inside and outside of the case 100.

The fixing bracket 11 is integrally molded with the case 100, and a metal collar 21 is insert-molded. The ignition coil 1 is fixed to a head cover E of the engine by bolts (not shown) which penetrate the collar 21. Then, the upper opening of the case 100 is sealed by a lid 23 made of resin. An annular groove 108 is provided in the upper opening of the case 100, and the O-ring 25 for sealing is housed therein.
00 and the lid 23 are sealed.

The transformer section 5 in the accommodation chamber 102 has an iron core 502 forming a magnetic path, magnets 504 and 506, and an auxiliary core 508. The iron core 502 has a rod shape with a circular cross section, and is assembled by stacking thin silicon steel plates so that the cross section has a substantially circular shape. At both ends of the iron core 502, magnets 504 and 506 having a polarity opposite to the direction of the magnetic flux generated by being excited by the coil are provided, respectively. An adhesive tape is wound between the iron core 502 and the magnets 504 and 506 to temporarily fix them, but the adhesive tape is not shown in FIGS. 1 and 2.

Further, the transformer section 5 includes a secondary spool 51.
0, a secondary coil 512, a primary spool 514, and a primary coil 516. Secondary spool 510
Is a resin molded product and is formed into a cylindrical shape having flanges at both ends, one end on the lower side thereof is substantially closed by a bottom portion 510a, and the secondary spool 51 is formed into a cylindrical shape with a bottom.
The magnet 506 and the iron core 502 are housed inside the 0.
A secondary coil 512 is wound around the outer circumference. The secondary spool 510 has a step portion 1 at a bottom portion 510a at one end thereof.
It has a protrusion 510b that comes into contact with 06 for axial positioning in the accommodation chamber 102, and also has a circumferential positioning protrusion 510c that protrudes in the radial direction of the bottom 510.

A secondary coil 512 is provided on the bottom portion 510a.
A terminal plate 33 having one end electrically connected thereto is fixed, and a spring 27 for contacting the cup 15 is fixed to the terminal plate 33. The terminal plate 15 and the spring 27 function as a spool-side conductive member, and the high voltage induced in the secondary coil 516 causes the terminal plate 33 spring 2 to operate.
It is supplied to the spark plug through 7, the cup 15, and the spring 17. The spring 27 is wound so that all the windings are spiral when viewed from the axial direction.

The primary spool 514 is a resin molded product and is formed into a cylindrical shape having flanges at both ends, and one end on the upper side thereof is substantially closed by a lid portion 514a and formed into a bottomed cylindrical shape. A primary coil 516 is wound around its outer circumference. The primary spool 514 is the secondary spool 510.
It is provided to cover the outside of. Therefore, the iron core 502 and the magnets 504 and 506 are sandwiched between the lid 514a and the bottom 510a. A groove 514b that fits into the protrusion 510c of the secondary spool 510 is formed at the lower opening end of the primary spool 514, and the secondary spool 510 and the primary spool 514 are positioned in the circumferential direction. Further, the secondary spool 510 and the primary spool 514 are welded together by melting the resin material of each other at the portions of the protrusion 510c and the groove 514b.

A circumferential positioning projection 514c is formed on the lid 514a so as to project in the radial direction.
4c fits in the groove 110 formed in the case 100. As a result, the primary spool 514 is positioned in the circumferential direction with respect to the case 100. Further, the primary spool 514 and the case 100 are welded by melting the resin material of each other at the portions of the protrusion 514c and the groove 110.
As a result, the primary spool 514 and the case 100 are fixed.

Further, the primary coil 51 is attached to the lid 514a.
A plurality of terminals to which both ends of 6 and one end of the secondary coil 512 are connected are held. These terminals are connected to the connector pin 19 of the connector 9 and the control circuit section 7. The control circuit section 7 has three leads, and these leads are soldered to the connector pins 19 and the terminals on the lid section 514a, so that the control circuit section 7 is covered with the lid section 514a.
Is held on.

The control circuit section 7 is formed by resin-molding a power element for connecting and disconnecting a current flowing through the primary coil 516 and a control circuit as an igniter for generating a control signal for the power element. A body heat sink 702 is adhered to the lid 23 side. Primary spool 5
An auxiliary core 508 is mounted on the outer side of 14. The auxiliary core 508 is formed by rolling a thin silicon steel plate into a cylindrical shape with a gap left in the circumferential direction, and has a length from the outer peripheral position of the magnet 504 to the outer peripheral position of the magnet 506. The auxiliary core 508 is held by the flanges at both ends of the primary spool 514.

A housing chamber 102 housing the transformer section 5 and the like
The inside is filled with insulating oil 29 up to the liquid level shown in FIG. 1 leaving a slight air space. The insulating oil 29 is supplied to the lower end opening of the primary spool 514, the opening 514d formed at substantially the center of the upper lid 514a of the primary spool 514, the upper end opening of the secondary spool 510, and the secondary spool 5.
It penetrates through an opening 510d formed in the lower outer peripheral wall of the device 10 to ensure electrical insulation of the secondary coil 512, the primary coil 516, and the like.

Next, the shape of each component will be described in more detail together with the procedure for assembling the ignition coil of this embodiment. 3 to 6 are partial partial cross-sectional views showing the procedure for assembling the transformer portion 5 of the ignition coil 1. 3 is a partial cross-sectional view of the iron core unit, FIG. 4 is a partial cross-sectional view showing a state where the iron core unit is housed in the secondary spool, FIG. 5 is a partial cross-sectional view showing a state where a primary spool is further mounted, and FIG. It is a fragmentary sectional view showing the state where an auxiliary core was attached. 7 is a sectional view taken along line VII-VII in FIG. In addition, FIG. 4, FIG.
In FIG. 6, illustration of each steel plate of the iron core is omitted.

As shown in FIGS. 3 and 7, the iron core 502 is formed by stacking a plurality of thin silicon steel plates having slightly different widths so as to have a substantially circular cross section, and bonding the steel plates to each other in a rod shape. There is. Magnets 504 at both ends of the iron core 502,
506 is positioned and the adhesive tape 31 is provided between the iron core and the magnet.
Then, the two are fixed together to form an iron core unit shown in FIG.

Next, the iron core unit is housed in the secondary spool 510 as shown in FIG. Secondary spool 5
A secondary coil 512 is pre-wound on the outside of 10. The secondary coil 512 is wound around one end of the spool 510 so that the cross section has a triangular shape, and then the winding is performed by sequentially moving in the axial direction while winding in a radial direction by using the inclined surface. The potential difference between the windings is reduced to ensure high voltage and low voltage insulation. On the inner peripheral surface of the secondary spool 510 on the bottom 510a side, three locking plate-like protrusions 510 are formed.
e are arranged at equal intervals. These protrusions are formed with an inclined surface during resin molding and are crushed by the corners of the magnet 506 when the iron core unit is housed. Therefore, after the iron core unit is housed, the crushed protrusions 5
10e contacts the outer peripheral surface of the magnet 506 to fix the magnet 506 in the radial direction.

A terminal plate 33 is attached to the bottom of the secondary spool 510, the spring 27 is fixed to the terminal plate 33, and one end of the secondary coil 512 is electrically connected to the terminal plate 33. ing. Next, the primary spool 514 is shown in FIG.
Wear it like. A primary coil 516 is pre-wound on the outside of the primary spool 514, and the terminal 35 is fixed on the lid portion 514a of the primary spool 514.
Inside the lid 514a, the protrusion 5 of the secondary spool 510 is
Three protrusions 514e similar to 10e are provided at equal intervals. These protrusions 514e are crushed by the corners of the magnet 504 when the primary spool 514 is mounted. Therefore, after the iron core unit is housed, the crushed protrusions 5
14e contacts the outer peripheral surface of the magnet 504 to fix the magnet 504 in the radial direction.

After this, the inner circumference of the open end of the primary spool 514 and the outer circumference of the bottom 510a of the secondary spool 510 are partially melted to form welded portions 37 and 39, and both spools are welded and fixed. Thereby, the iron core 502 and the magnet 50
4, 506 are sandwiched and fixed by both spools 510, 514. Next, as shown in FIG. 6, the primary spool 514
The auxiliary core 508 is attached to the outside of the. In this way, the transformer section 5 is assembled.

As shown in FIG. 7, the auxiliary core 508 has a slit 508a to reduce the eddy current generated in the circumferential direction of the auxiliary core. The transformer section 5 is inserted into the case 100 through the upper opening. And the lid portion 51
The outer periphery of 4a and the inner wall surface of the case 100 are partially melted to form a plurality of welded portions, and both members are welded and fixed.

Then, after the leads of the control circuit section 7 are soldered to the terminals to complete the electrical connection, the insulating oil 29
And the lid 23 is attached to the open end of the case 100.
The lid 23 has an engaging arm that engages with an engaging claw formed at the open end of the case 100. The engaging claw and the engaging arm are engaged with each other, and the both are welded together. To close the case 100.

According to the embodiment described above, the iron core 502 and the magnets 504 and 506, which are a plurality of magnetic path constituent members, are sandwiched between the primary spool 510 and the secondary spool 514. You can Moreover, since the protrusions 510e and 514e that are crushed by the corners of the magnets 504 and 506 are provided inside the primary spool 510 and the inside of the secondary spool 514, the magnet 504,
506 is held without play in both the axial direction and the radial direction. Further, since the spring as the connecting means is held on the bottom portion 510a of the secondary spool, the transformer portion 5 including the secondary coil 510 can be connected to the cup 15 only by inserting it into the case 100. In addition, since the storage chamber 102 is filled with the insulating oil 29, it has a narrow shape that can be inserted into the plug tube and has a small gap between the components. Insulation property is stable and high insulation is obtained over a long period of time without deterioration.

In this embodiment, the magnetic path is composed of one iron core and two magnets, but a magnet may be sandwiched between two iron cores. The iron core is preferably circular, but may have a polygonal or quadrangular cross section, and may be formed by stacking thin silicon steel plates, or by bundling silicon steel wire rods. In addition, in this embodiment, the auxiliary core 508 is provided to form an incomplete closed magnetic circuit.
The inner auxiliary core may be provided outside the case 100. Further, the auxiliary core may be formed by stacking a plurality of silicon steel plates and rolling them.

The case is not limited to a cylindrical shape, but a polygonal shape,
The spool may have a rectangular tubular shape, and the spools may have the same shape, and may have a rectangular tubular shape. In addition, the primary spool 51
4 is welded to the case 100 and the transformer section 5 is fixed in the case 100, but the transformer section 5 may be fixed by pressing the primary spool 514 with the lid 23, and an elastic member such as a spring may be interposed. May be. Further, the primary spool 514 may be inside and the secondary spool 510 may be outside. In addition, the bottom 510 of the secondary spool 510
It is not necessary for a to completely close the lower opening of the secondary spool 510, as long as it is a bottom portion capable of supporting the iron core unit in the axial direction, and the insulating oil 29 circulates and a hole is formed to allow convection. Is desirable. Similarly, the primary spool 51
The fourth lid portion 514a also desirably has the opening 514d as in the first embodiment, and it is important that the lid portion 514a has a shape capable of supporting the iron core unit in the axial direction. In addition, one of the primary spool and the secondary spool may be integrally formed with the case, and the primary coil or the secondary coil formed into a coil shape by using a self-bonding wire or the like may be inserted. Further, the bottom portion and the lid portion as the closing portion formed on the primary spool and the secondary spool may be separate parts.

Further, the control circuit section 7 has a heat sink 702.
However, an aluminum plate serving as a heat sink may be embedded in the lid 23 and the aluminum plate and the control circuit section 7 may be in contact with each other in a heat transferable manner. In addition, in this embodiment, the ignition coil 1 has a structure shown in FIGS.
Although it is assumed that the ignition coil 1 is installed in the engine with the axial direction substantially aligned with the gravity direction as shown in FIG. 2, the ignition coil 1 may be installed in the engine with the axial direction substantially aligned with the horizontal direction. , In this case, the insulating oil 2 in the storage chamber 102
An air chamber is formed in the lid so that air does not enter the transformer unit 5 after the injection of 9.

Although a plurality of magnetic path forming members are sandwiched between the two spools in the above embodiment, the iron core and the magnet as the magnetic path forming members may be sandwiched by the case lid. Next, a second embodiment to which the present invention is applied will be described. FIG. 8 is a cross-sectional view of the main part of the second embodiment, and FIG. 9 is a plan view of the main part of the lid viewed from the IX direction in FIG. The same components as those in the first embodiment are designated by the same reference numerals.

In the second embodiment, the magnet 504 is held by the lid 41 that closes the open end of the case 100. The lid 41 is provided with a column portion 410a as an abutting portion at the center thereof, and a magnet 504 is provided at the tip thereof.
A cylindrical portion 410b that is slightly larger than the outer diameter of is formed.
As shown in FIG. 8, inside thereof, a protrusion 410c similar to the protrusion 514e of the first embodiment is provided.
The protrusion 410c is crushed by the corner portion of the magnet 504 and comes into contact with the outer periphery of the magnet 504, and holds the magnet 504.

The primary spool 518 of this second embodiment is
Almost the same as the primary spool 514 of the first embodiment,
The lid 518a has an opening 518b that allows the pillar 410a to be inserted therein. Further, in this embodiment, the control circuit section 7 is not housed in the ignition coil 1. The control circuit section 7 is connected via a connector 9 and is housed in a circuit container fixed to the vehicle body.

In this embodiment, first, the secondary spool 510 is
The primary spool 518 is attached to the above to assemble a coil unit, the coil unit is housed in the case 100, and then the iron core unit is inserted through the opening 518b. After that, the insulating oil 29 is injected and the lid 41 is attached to seal the storage chamber 102. Therefore, the iron core unit has a secondary spool 510.
It is sandwiched between the bottom portion 510a of the sheet and the lid 41.

[0043]

According to the configuration and operation of the present invention described above, a plurality of magnetic path constituting members such as an iron core and a magnet are provided.
Since it is sandwiched between parts such as the primary spool and the secondary spool, or between the spool and the lid of the case,
The simple structure enables reliable holding, and simplifies the process of assembling the ignition coil.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a first embodiment of an ignition coil to which the present invention is applied.

FIG. 2 is a vertical sectional view showing a first embodiment of an ignition coil to which the present invention is applied.

FIG. 3 is a partial cross-sectional view of the iron core unit of the first embodiment.

FIG. 4 is a partial cross-sectional view showing a state where the iron core unit of FIG. 3 is mounted on a secondary spool.

FIG. 5 is a partial cross-sectional view showing a state in which a primary spool is further mounted in the state of FIG.

FIG. 6 is a partial cross-sectional view showing a state in which an auxiliary core is further mounted in the state of FIG.

7 is a sectional view taken along line VII-VII in FIG.

FIG. 8 is a cross-sectional view of an essential part of the second embodiment.

9 is a plan view of a main part of FIG. 8 seen from the direction of the arrow IX.

[Explanation of symbols]

 1 Ignition coil 100 Case 102 Storage chamber 3 Connection part 5 Transformer part 502 Iron core 504 Magnet 506 Magnet 508 Auxiliary core 510 Secondary spool 512 Secondary coil 514 Primary spool 516 Primary coil 7 Control circuit part 9 Connector 11 Bracket part 23 Lid 29 Insulation oil

Claims (10)

[Claims] 1. A rod-shaped magnetic path forming member that allows a magnetic flux to pass therethrough, a spool provided on the outer periphery of the magnetic path forming member, a coil held by the spool, the magnetic path forming member, the spool, and the coil. In the ignition coil including a case that accommodates the magnetic path forming member, the magnetic path forming member is configured by connecting a plurality of members in an axial direction, and a plurality of members of the magnetic path forming member is an axis of the magnetic path forming member. Ignition coil characterized in that it is sandwiched by a plurality of parts assembled along the direction 2. The case is formed in a tubular shape, a connecting portion for connecting to an ignition plug is provided at one end of the case, and an accommodating chamber in which a conductive member conducting to the connecting portion is exposed is formed at a bottom portion of the case. The ignition coil according to claim 1, wherein the spool, the coil, and the magnetic path forming member are housed in a chamber. 3. The spool has cylindrical first and second spools that are multiply provided on the outer periphery of the magnetic path forming member, and the coil is a primary coil held by the first spool. And a secondary coil held by the second spool, wherein the first spool includes a closing portion that comes into contact with one end side in the axial direction of the magnetic path forming member, and the second spool is And a closing portion that is in contact with the other end of the magnetic path forming member in the axial direction and holds a plurality of members of the magnetic path forming member together with the closing portion of the first spool. Or the ignition coil according to 2. 4. The second spool is accommodated in the accommodating chamber with the closing portion facing the bottom of the accommodating chamber,
The ignition coil according to claim 3, wherein the closing portion is provided with a spool-side conductive member that comes into contact with the conductive member exposed on the bottom portion. 5. The spool has a closing portion that comes into contact with one end side of the magnetic path forming member in the axial direction, and the case has a lid portion that is assembled from the axial direction of the magnetic path forming member. The lid portion includes an abutting portion that abuts on the other end side of the magnetic path forming member in the axial direction and that holds a plurality of members of the magnetic path forming member together with the closing portion of the spool. The ignition coil according to item 1 or 2. 6. The spool is housed in the storage chamber with the closing portion facing the bottom portion of the storage chamber, and the closing portion is provided with a spool-side conductive member that comes into contact with a conductive member exposed at the bottom portion. The ignition coil according to claim 5, wherein the ignition coil is provided. 7. The magnetic path forming member has a rod-shaped iron core and two magnets provided at both ends of the iron core, according to claim 1. Ignition coil. 8. Insulating oil is injected into the case,
The ignition coil according to any one of claims 1 to 7, wherein the coil is immersed in the insulating oil. 9. An ignition coil for supplying a high voltage to an ignition plug of an internal combustion engine, comprising: a case formed in a tubular shape to form an accommodation chamber; and a tubular shape having one end side closed by a closing portion, A secondary spool housed in the chamber, a secondary coil retained by the secondary spool, and a tubular shape having one end side closed by a closing portion, and the closing portion is provided on the opening end side of the secondary spool. A primary spool that is positioned and coaxial with the secondary spool and that is housed in the storage chamber; a primary coil that is held by the primary spool; and notches that are provided on the outer periphery of the secondary spool and the primary spool. A cylindrical auxiliary core having: and an insulating oil that is injected into the accommodation chamber and in which at least the primary coil and the secondary coil are immersed, a closing portion of the secondary spool, and the primary Ignition coil, characterized in that it comprises a magnet provided rod-shaped iron core is held between the closed portion of the pool, and at both ends of the iron center. 10. The ignition coil according to claim 1, wherein a control circuit unit is housed in the case.