WO2003071562A1

WO2003071562A1 - Ignition coil for internal combustion engine

Info

Publication number: WO2003071562A1
Application number: PCT/JP2002/001550
Authority: WO
Inventors: Hideki Ootsuki; Kenji Nakabayashi; Hiroyuki Tanaka; Yoshiaki Shimazu
Original assignee: Hitachi, Ltd.; Hitachi Car Engineering Co., Ltd.
Priority date: 2002-02-21
Filing date: 2002-02-21
Publication date: 2003-08-28
Also published as: JPWO2003071562A1

Abstract

A core forming a closed magnetic circuit and primary and secondary coils are provided in a coil case, with the primary and secondary coils disposed around a single bobbin in an axial-direction line. The secondary coil is wound at the middle of the bobbin, and the primary coil is wound divided into segments - one on the low voltage side, and the other on the high voltage side of the secondary coil. The leader line on the low voltage side of the secondary coil is passed between the bobbin and the primary coil and connected to a terminal at the bobbin’s one end. A leader line connecting windings of the primary coil is routed over the secondary coil in non-contact with it. An independent-ignition type ignition coil, having primary and secondary coils wound around one bobbin in an axial- direction line, can be reduced in sized and improved in output by the above arrangement.

Description

Specification

Ignition coil for internal combustion engine

The present invention relates to an ignition coil (ignition device) for an internal combustion engine, and more particularly to a cylindrical coil suitable for being used by being directly connected to an ignition plug and housed in a plug hole of a cylinder head of the internal combustion engine. It relates to an ignition coil. Background art

As an ignition coil for an internal combustion engine, a so-called independent ignition type ignition coil which is prepared for each cylinder of the internal combustion engine and is used directly connected to a spark plug is known.

This type of ignition coil consists of a type in which a primary coil and a secondary coil are concentrically arranged around a core that forms a magnetic path, and a type in which a primary coil is arranged in a single bobbin in the axial direction. A type in which a winding part and a winding part of a secondary coil are arranged is known.

The latter type is disclosed, for example, in Japanese Patent Application Laid-Open No. 2-230964.

Since the ignition coil of the independent ignition type is housed in the plug hole of the cylinder head of the internal combustion engine and used, the space of the coil part is very narrow, and how high output is in this limited space The challenge was how to supply the ignition energy to the spark plug.

An object of the present invention is to provide a primary bobbin with one bobbin so as to be arranged in the axial direction. It is an object of the present invention to provide an ignition coil device for an internal combustion engine, which can be reduced in size and improved in output in an independent ignition type ignition coil of a type in which a coil and a secondary coil are wound. Disclosure of the invention

In order to achieve the above object, the present invention is basically configured as follows.

(1) An ignition coil for an internal combustion engine of an independent ignition type in which a primary coil and a secondary coil are arranged on one bobbin so as to be arranged in the axial direction, and configured as follows. ,

That is, the secondary coil is wound around the center of the bobbin f, and the primary coil is divided and wound on the low voltage side and the high voltage side of the secondary coil. It is characterized by.

Conventionally, this type of ignition coil has a primary coil arranged in one area and a secondary coil arranged in the other area in the -axis direction of one bobbin. '

On the other hand, in the present invention, the primary coil is dividedly wound around the low voltage side and the high voltage side of the secondary coil in the axial direction of the bobbin. By splitting the primary coil in this way, the coupling coefficient between the primary coil and the secondary coil can be increased as compared with the conventional case. Therefore, it is possible to manufacture a high-output internal combustion engine ignition coil in a limited space.

(2) Along with the above basic configuration, the following coil wiring structure is also proposed. The lead wire on the low voltage side of the secondary coil is passed between the bobbin and the primary coil through a groove provided at one end of the bobbin, and thus the secondary coil is connected to one end of the bobbin. Connected to the provided terminal.

Further, out of the bobbin, one end outer periphery adjacent to the low voltage side of the secondary coil is defined as a low voltage side outer periphery, and one end outer periphery adjacent to the high voltage side of the secondary coil is defined as a high voltage side outer periphery. The primary coil is wound around the outer periphery of the bobbin on a low voltage side. Then, the lead wire at the end of winding of the primary coil in the outer periphery on the low voltage side is wrapped around the collars provided on the low voltage side and the high voltage side along the outside of the secondary coil, and the rest of the coil remains. It is wound around the outer periphery of the high voltage side, and the lead wire at the end of the winding of the primary coil on the outer periphery of the high voltage side again extends along the outer side of the secondary coil on the high voltage side and low side of the bobbin. It is wrapped around the collar on the voltage side to be electrically connected to the terminals. 'In this way, even if the primary coil is divided and wound on both the low voltage side and the high voltage side of the secondary coil,' the interference between both coils is eliminated and the wiring of the coil is pulled out. It can be turned around.

(3) In addition, the following independent ignition type ignition coil for internal combustion engines is proposed.

The primary coil and the secondary coil are arranged side by side on one bobbin in the axial direction. The core is a steel plate having a cross section perpendicular to the magnetic path laminated in a D-shape, and has a closed magnetic path structure. The bobbin also has a cross section perpendicular to the axial direction conforming to the cross sectional shape of the core. The core is a closed magnetic circuit The bobbin fits into one of the longitudinally arranged magnetic paths (hereinafter, referred to as “magnetic path A”), and the other magnetic path (hereinafter, referred to as “magnetic path A”) is parallel to the magnetic path A. “The magnetic path B” is disposed along the outside of the primary coil and the secondary coil. Each of the brim portions provided on the bobbin has a part of an outer edge forming a straight line, and a side surface corresponding to the straight side of the cross section D of the magnetic path B is applied to or close to the outer edge part. The magnetic path B is arranged so as to perform the above.

In this way, the entire core of the closed magnetic circuit type that can improve the output is put together in a compact as a single coil assembly together with the primary coil and secondary coil, and stored in a cylindrical case. .

'() We also propose the following invention.

A core forming a closed magnetic circuit, a primary coil and a secondary coil disposed on a part of the outer periphery of the core via a bobbin, and an ignition drive circuit unit for driving the primary coil and the secondary coil In the ignition coil for the internal combustion engine 5, the entire closed magnetic circuit type core and the ignition drive circuit unit are accommodated in a cylindrical case accommodating the primary coil and the secondary coil. Further, the bobbin is characterized in that the secondary coil is wound around a center portion, and the primary coil is dividedly wound around both ends of the bobbin so as to sandwich the secondary coil.

0 Placing the primary coil on both sides of the secondary coil in the axial direction increases the coupling coefficient of the coil, and can improve the compactness and storage of the coil assembly. Therefore, the drive circuit unit for the ignition coil can be stored in the coil case. In addition, close with this drive circuit. By housing the entire core of the magnetic path in the cylindrical case, the mounting density of the components in the coil case can be increased. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a longitudinal sectional view of an ignition coil for an internal combustion engine according to a first embodiment of the present invention, FIG. 2 is a longitudinal sectional view (A-A line sectional view) of the above embodiment, FIG. 3 is an explanatory view schematically showing the layout of the windings of the primary coil and the secondary coil of the ignition coil according to the above-described embodiment and the drawing out structure thereof, and FIG. Top view of the ignition coil, Fig. 5 is a longitudinal sectional view showing the coil case of the above embodiment with internal mounting parts removed, and Fig. 6 is a front view showing the disassembled state of the core used in the above embodiment. FIG. 7 is a partial cross-sectional view of the bobbin used in the above embodiment, and FIG. 8 is a circuit diagram of the igniter used in the above embodiment. Is a cross-sectional view showing the configuration of the ignition system, and FIG. 10 is an internal combustion engine according to a second embodiment of the present invention. Vertical 'plane. Figure of the ignition coil. BEST MODE FOR CARRYING OUT THE INVENTION

Embodiments of the present invention will be described with reference to the drawings.

First, prior to describing the structure of the ignition coil according to the present embodiment with reference to FIGS. 1 to 7, an electric circuit of the ignition coil according to the present embodiment will be described with reference to FIG.

In the figure, 2 is a core for forming a magnetic path of the ignition coil, and 4 is a primary core. , 5 is a secondary coil.

One end 4 ′ of the primary coil 4 and one end 5 ′ of the secondary coil 5 on the low voltage side are connected to a power supply terminal 9 通 communicating with a battery power supply. The other end 4 の of the primary coil 4 is connected to a terminal 10 A of a switching circuit 105 of an ignition drive circuit unit (hereinafter referred to as “igniter” 5) 6.

One end 5 ^f on the high voltage side of the secondary coil 5 is electrically connected to the ignition plug 10 via the high voltage diode 20 and the high voltage terminal 16.

10 Ignition 6 is the main switching element of the primary coil: Insulated gate type bipolar transistor. Evening (hereinafter referred to as “IGBT”) '100 and sub-IGBT 101 And a current limiting circuit 109 for limiting the current flowing through the primary coil 4, a current detecting resistor 102, an ignition signal input resistor 107, a bleeder resistor 108, etc. Have been. 15 The current detection resistor 102 is provided between the sub-IGBT 101 emitter and GND. Between the gate and collector of the IGBT 105, insert a phase direction polysilicon diode 103 composed of a polysilicon with excellent temperature characteristics, and set the primary voltage to 400 ~. Clamping at 550V.

0 Insert a leader resistor 108 between the signal input terminal 9c of signal 6 and ground (GND), set the contact current of the input signal connection to 1 mA or more, and fix the terminal 9C Sufficient connection reliability is obtained even with Sn plating. In the above circuit configuration, the primary current flowing through the primary coil 4 is interrupted by the IGBT (switching element) 100 based on the ignition signal, so that the secondary coil 5 has a high voltage for ignition. Is induced. The high voltage diode 20 prematurely supplies the high voltage generated by the secondary coil 5 to the ignition slug 10 via the 髙 voltage terminal 16 and the spring 17 (see Fig. 1). Plays a role in preventing ignition.

The power supply terminal 9A (VB), GND terminal 9B, and ignition signal input terminal 9C (S) are arranged on the connector 1C of the ignition coil device (see FIGS. 1 and 4).

Here, the structure of the ignition coil will be described with reference to FIGS.

The ignition coil case (hereinafter referred to as the “coil case”) 1 is made of a thermoplastic synthetic resin, such as polybutylene terephthalate (hereinafter “PBT”) or polynuenylene sulfide (hereinafter “PPS”). ) It is made by molding into a slender cylindrical shape with PPS etc.).

The coil case 1 has a coil housing 1A, a spark plug connection 1D, a igniter case 1B for housing the igniter 6, and a connector 1C for external terminal connection. Molded into.

The coil storage section 1A stores the closed magnetic circuit core 2, the primary coil 4, and the secondary coil 5.

The igniter case 1B has, for example, a box shape, and accommodates an igniter 6 for driving an ignition coil therein.

The core 2 of the ignition coil forms a substantially rectangular annular closed magnetic path, and its length is The magnetic paths A and B in the hand direction are arranged parallel to the axial direction of the coil case 1. As shown in FIG. 6, the core 2 is divided into 201 and 202, and the cross-section of the core 2 perpendicular to the magnetic path has a D-shape. The core 2 is formed by press-stacking a silicon steel sheet or a directional silicon steel sheet having a thickness of 0.2 to 0.5 mm.

By connecting the split cores 201 and 202 together, an annular closed magnetic path is formed, and a permanent magnet 8 is interposed at the joint. The permanent magnet 8 is magnetized in a direction opposite to the magnetic direction excited by the primary coils 4A and 4B, and serves to prevent magnetic saturation when the primary coil is energized.

The bobbin 3 for winding the primary coil 4 (4A, 4B) and the secondary coil 5 is made of a thermoplastic resin such as PPS or modified polyphenylene oxide (hereinafter referred to as “modified PPO”). It is molded, and its cross section perpendicular to its axial direction has a substantially D-shape along with the cross section of the core 2 (see FIGS. 3 and 6).

On the bobbin 3, a secondary coil 5 is wound at the center, and the secondary coil 5 uses an enameled wire having a wire diameter of about 0.03 to 0.06 mm, for a total of 100 mm. It is wound about 0 to 30000 times. This split winding is performed by dividing the winding area of the secondary coil 5 by a plurality of collars 33.

As shown by reference numerals 4A and 4B, the primary coil 4 is divided and wound on the outer periphery of both ends of the bobbin 3, that is, adjacent to the low voltage side and the high voltage side of the secondary coil 5.

The split winding of the primary coil 4 is performed after the secondary coil 5 is wound. It is. FIG. 3 schematically shows the winding mode.

In FIG. 3, (a) is a front view of the bobbin 3, (b) is a view in the direction of the arrow D, (c) is a BB sectional view, (d) is a CC sectional view, and (e) is a sectional view. It is an arrow E view.

In Fig. 3 (b), the arrow marked on bobbin 3 is the winding path of primary coil 4.

Here, of the outer circumferences of both ends of the bobbin around which the primary coil 4 is divided and wound, the outer circumference of one end adjacent to the low voltage side of the secondary coil 5 is placed on the low voltage side outer circumference 3 A and the high voltage side of the secondary coil 5. The outer periphery of the adjacent one end is referred to as a high voltage side outer periphery 3B.

In the flange 31 formed at the lowermost end of the bobbin 3 on the low-voltage side, protrusions 37 and 38 are arranged on the end face of the flange 31 so as to face each other with a core (magnetic path) interposed therebetween.

The protrusion 3 7 has a bracket (relay terminal; pin) for connecting one end 4 <on the power supply side of the primary coil 4 and one end 5 ′ on the low voltage side of the secondary coil 5 to the power terminal 9 A. 2 and a metal fitting (relay terminal; pin) 11 for connecting one end 4〃 of the end of winding of the primary coil 4 to the terminal 1 OA of ignition 6 are insert-molded.

First, before the primary coil 4, the secondary coil 5 is divided and wound around the center of the bobbin 3. As shown in Figs. 3 (a) and (b), the secondary coil 5 has a lead wire 5 'on the winding start side (low voltage side) wrapped around the metal fitting (relay terminal) 12 (wrapped). Can be After that, it passes through the axially extending groove 41 provided on the outer circumference 3 A of one end of the bobbin 3, and It is guided to the winding area and wound.

As shown in Fig. 7, the grooves 41 are formed with, for example, two small gentle protrusions 300, 301 on a part of the bobbin surface in consideration of contact with the primary coil 4. By doing so, it is secured between the convex portions. Further, the depth of the groove 41 is larger than the wire diameter of the secondary coil. V-shaped cuts 3 1 3 and 3 2 3 are formed in the flanges 3 1 and 3 2 located at both ends of the groove 41 of the flanges of the bobbin 3 [Fig. b) (c)] _c The bottoms of the cuts 3 1 3 and 3 2 3 communicate with the grooves 41. The lead wire 5 ′ of the secondary coil passes through the collar portions 31 and 32 through the cuts 3 13 and 3 23.

The lead wire 5 引き出し on the high voltage side of the secondary coil 5 was guided to the guide groove 3 '53 3 provided in the flange 35 on the high voltage side of Bozen '3, and was provided at one end of the bobbin 3 on the high voltage side. After being bridged over the guide groove 36 1 of the flange portion 36, it is connected to the high-voltage diode 20 [FIG. 3 (b) (e)].

The high-voltage diode 20 is held on the outer surface of the flange 36 by a support portion 39 integrally formed with the flange.

As shown in Fig. 3 (b), the primary coil 4 has one end 4 'tied (wrapped) around a metal fitting (relay terminal) 12 and a notch 3 From 14, it is guided to the low voltage side outer periphery 3 A of the bobbin 3 [Fig. Thus, one winding portion 4A of the primary coil is formed. After that, the lead wire 4 A at the end of the primary coil winding in the winding part 4 A is connected to the guide groove 32 1 provided in the low voltage side flange 32 and the guide groove provided in the high voltage side flange 35. 3 5 Multiplied by 1 [Fig. 3 (a), (c), (d)]. Therefore, the lead wire 4 A ′ of the primary coil 4 is guided to the high voltage side outer periphery 3 B along the outside of the secondary coil 5 without contacting the secondary coil. Then, the remainder of the primary coil 4 is wound around the outer periphery 3B on the low voltage side as shown by reference numeral 4B.

The lead wire 4 B ′ at the end of the primary coil winding wound around the high voltage side outer periphery 3 B is provided from the guide groove 35 2 provided in the high voltage side flange 35 to the low voltage side collar 32. The guide groove 3 2 2 is further extended over the guide groove 3 1 1 of the flange 3 1 at one end on the low voltage side, and is entangled with a fitting (relay terminal) 1 1 provided on the flange 3 1. Therefore, the lead wire 4 B ^{f of the} primary coil is also electrically connected to the relay terminal 1 に along the outside of the secondary coil 5 (in a non-contact state). ■

The relay terminal 11 is insert-molded into a protrusion 38 provided on the flange 32 on the low voltage side of the bobbin, and the above-mentioned lead wire 4 Β 'is entangled at one end thereof, and the other end 1 1 'Is connected to terminal 10 の of igniter 6 (receptor side of IGBT 100 in Fig. 8) as shown in Fig. 4.

By adopting the above-described winding mode, the lead wire 5 ′ on the low voltage side of the secondary coil 5 is connected to the bobbin 3 and the primary coil 4 via the groove 41 provided on the outer periphery of one end of the bobbin 3. (4A) and can be connected to the terminal 12 provided at one end of the bobbin. The groove 41 is deeper than the wire diameter of the secondary coil 5. Therefore, the lead wire 5 ′ of the secondary coil 5 can contact the winding area 3 A of the primary coil with the primary coil 4. It can be pulled out immediately.

In addition, when the primary coil 4 is wound, the lead wire 5 ′ of the secondary coil 5 does not interfere, and the disconnection of the secondary coil 5 can be prevented. In addition, the lead wires 4 A ′ and 45 B ′ of the split winding of the primary coil 4 are laid over the secondary coil 5, so that the secondary coil 5 has a low voltage side and a high voltage side. The primary coil 4 can be wound separately.

The bobbin 3 fits into the magnetic path A in the core having a D-shaped cross section. The other magnetic path B parallel to the magnetic path A is arranged along the outside of the primary coil 4 (4A, 4B) and the secondary coil 5. Each L0 disposed on the bobbin 3. The flanges 3 1, 3 2, 3 3, 3 5, 3 6 have their outer edges 3 1 ′, 3 2 ′, 3 3 ′, 3 5 ′, 3 · 6 'is cut in a straight line, and a flat surface in the magnetic path B (the side corresponding to the' straight side 'of the cross-section D in the magnetic path B) is applied to or close to the outer edge. Placed in '' Therefore, it is possible to assemble the core 2, the primary coil 4, and the secondary coil 5 into a compact 5, and the entire closed magnetic circuit can be stored in the cylindrical case 1 together with the primary coil and the secondary coil. become. '

Guide groove for bridging the lead wire of the primary coil 3 1 1, 3 2 1, 3 2 2, 3 5 1, 3 5 2 and plan for bridging the high-voltage side lead wire of the secondary coil Inner groove 3 5 3, 3 6 1 is a projection 3 1 5, 3 2 provided beside the cut section 0 3 1 z ヽ 3 2 ′, 3 5 ′, 3 6 ′ of the collar section 3 1, 3 2, 3 5, 3 6 5, 3, 5 5 and 3 6 2.

By passing the lead wires 4A ', 4B ", 5 of the primary coil and secondary coil through these guide grooves, the following advantages can be obtained. The lead wires 4 A ′ and 4 B ′ of the coil can be prevented from contacting the inner diameter of the outer diameter case 1 of the winding part of the secondary coil 5. Further, the secondary coil 5 can be prevented from contacting the outer diameter of the primary coil 4B and the inner diameter of the case 1. The cross section of the bobbin 1 may be elliptical.

The bobbin 3 is disposed between the core 2 and the secondary coil 5, and also has a function of insulating high voltage generated in the secondary coil 5.

The plurality of collars 33 for the secondary coil provided on the bobbin 3 are provided with cutouts 327 for dividing and winding the secondary coil 5. In the present embodiment, the ignition case 1B and the connector 1C are formed integrally with the coil case 1 but may be formed separately. 'The power supply terminal 9A, GND terminal 9B, and ignition' signal input terminal 9C are fixed to the connector section 1C by insert molding. Terminal 9A is connected to lower relay terminal 12 of substrate 7 (see Fig. 3 (b)), terminal 9B is connected to ground terminal 10B of igniter 6, and terminal 9C is connected. Is connected to the signal input terminal 10 C of the ignition 6. '

As shown in Fig. 9, IGBT 105 is bonded to heat sink 110, and heat sink 110 is connected to heat-dissipating copper or aluminum metal plate 1 as shown in Fig. 9. Adhered to 1 2 via silicon adhesive 1 1 1.

The ignition case 1B is provided with projections 210, 211 and mounting holes 211, 214 for mounting an ignition coil. Flexible epoxy is applied under vacuum between the inner periphery of bobbin 3 and the outer periphery of core 2. (E.g., 4 Torr or less), injecting and curing, or as shown in Fig. 2, covering the core 2 with a silicone rubber 230, forming a silicone rubber around the core 2, Put heat shrink tubing around core 2. This prevents electric field concentration and stress concentration between the secondary coil 5 and the core 2.

After the assembly of such an ignition coil (core 2, primary coil 4, secondary coil 5) and igniter 6, the epoxy resin 60 is immersed in coil 1 and igniter 1. Injected into vacuum 1B under vacuum (eg, 4 Torr or less).

0-A part 1 D into which a spark plug is inserted is provided with a spring 17 which also functions as a secondary current supply function. The coil case 1 is provided with a plug hole seal 61 so that water does not enter the plug hole and can be ventilated when it is inserted into the plug hole.

According to this embodiment, the following effects can be obtained. ..

5 A primary coil 4 and a secondary coil 5 are wound around one bobbin, a secondary coil 5 is wound at the center of the bobbin, and a primary coil is dividedly wound at both ends of the low voltage side and the high voltage side. Thus, the coupling coefficient between the primary coil and the secondary coil can be increased, and a high-output ignition coil for an internal combustion engine can be realized in a limited space. In addition, the primary coil can be divided and wound on the low voltage side and high voltage side of the secondary coil without interfering with the secondary coil, making coil winding work easier and cutting the coil. Quality assurance and quality assurance.

FIG. 10 shows another embodiment of the present invention. In Fig. 10 The same reference numerals as those in the first embodiment denote the same or common elements. In this embodiment, the mode of the divided winding of the primary coil 4 and the divided winding of the secondary coil 5 and the overall layout of the primary coil and the secondary coil are the same as those of the above-described embodiment. It is.

Here, the differences are explained.

As described above, arranging the primary coils 4A and 4B on the low voltage side and the high voltage side of the secondary coil 5 in one bobbin 3 increases the coupling coefficient of the coil and increases the coil assembly. This makes it possible to increase the compactness and the storage capacity.

Therefore, it is possible to secure a space inside the cylindrical coil case 1 for accommodating the entire closed magnetic circuit type core 2 together with the primary coils 4 and the secondary coil 5 and the ignition coil 6. . 'In this embodiment', the empty space of the coil case 1 is used effectively to store the signature 6.

Here, when the one end of the coil insertion side in the axial direction of the coil case 1 is set to the upper side and the side connected to the spark plug is set to the lower side, the connector for connecting the external terminal 'terminal' to the upper part of the coil case 1 Part 1C is formed. Also, the installation part of SIGNAY 6 is set lower than the position of connector part 1C.

Further, in this embodiment, the ignition coil mounting portion 1D and the spring 17 are made shorter than in the first embodiment. According to this embodiment, the ignition coil can be made even more compact. In addition, shortening the spring 17 has the effect of suppressing the occurrence of ignition noise. Industrial applicability

According to the present invention, the primary coil and the secondary coil are coupled by dividing and winding the secondary coil at the center of the bobbin and the primary coil at both ends of the low voltage side and the high voltage side. The coefficient can be increased, and a high-output internal combustion engine ignition coil can be provided within a limited space.

Claims

The scope of the claims

1. An ignition coil mounted on each plug hole of a cylinder head of an internal combustion engine, comprising: a core forming a magnetic path; a primary coil disposed on a periphery of the core via a bobbin; A secondary coil, wherein the 5 primary coil and the secondary coil are arranged in a single bobbin in the axial direction,

The secondary coil is wound around a center portion of the bobbin, and the primary coil is divided and wound on a low voltage side and a high voltage side of the secondary coil. Ignition coil.

L0 2. An ignition coil attached to each plug hole of a cylinder head of an internal combustion engine, comprising: a core forming a magnetic path; a primary coil and a secondary coil disposed around the outer periphery of the core via a bobbin. A primary coil and a secondary coil, wherein the primary coil and the secondary coil are arranged side by side in one bobbin in the axial direction.

5 The secondary coil is wound around the center of the bobbin, the primary coil is divided and wound on the low voltage side and the high voltage side of the secondary coil, and the low voltage of the secondary coil is wound. The lead wire on the side is passed between the bobbin and the primary coil through a groove provided on the outer circumference of one end of the bobbin, and is connected to a terminal provided on one end of the bobbin. 0 ignition coil for fuel engine.

3. A ignition coil mounted in each plug hole of a cylinder head of an internal combustion engine, the core forming a magnetic path; A secondary coil; The primary coil and the secondary coil are arranged in a single bobbin in the axial direction.

The secondary coil is wound around the center of the bobbin, the primary coil is divided and wound on the low voltage side and the high voltage side of the secondary coil, and 5 the secondary coil of the bobbin The outer periphery of one end adjacent to the low voltage side of the secondary coil is defined as the outer periphery of the low voltage side, and the outer periphery of the one end adjacent to the high voltage side of the secondary coil is defined as the outer periphery of the high voltage side. It is wound from the outer circumference, and the lead wire at the low voltage side outer circumference at the end of winding of the primary coil is wound around the collar provided on the low voltage side and the high voltage side along the outside of the secondary coil. The remainder of the coil is wound around the outer periphery of the high voltage side, and the winding of the primary coil at the outer periphery of the high voltage side ends.

-For the internal combustion engine, wherein the lead wire of-is again extended along the outside of the secondary coil to the high voltage side and low voltage side flanges of the bobbin and is electrically connected to the terminal. Ignition coil. ,Five

4. The ignition coil for an internal combustion engine according to claim 3, wherein a guide groove for passing the lead wire of the primary coil is formed in a low voltage side, high voltage flange portion of the bobbin.

5. A collar provided at one end of the bobbin includes a metal fitting for connecting one end of a power supply side of the primary coil and one end of a low voltage side of the secondary coil to a power supply terminal 0; The ignition coil for an internal combustion engine according to any one of claims 1 to 4, wherein a metal fitting for connecting one end of the winding end of the next coil to a terminal of the switching element of the ignition drive circuit is insert-molded. .

6. The core according to any one of claims 1 to 4, wherein the core is a rectangular annular core forming a closed magnetic circuit, and the entire annular core is housed in a cylindrical case together with a primary coil and a secondary coil. The ignition coil for an internal combustion engine according to the item.

7. Each part of the cylinder head of the internal combustion engine. What is claimed is: 1. An ignition coil for an internal combustion engine, comprising: a ignition coil mounted in a lug hole, comprising: a core forming a magnetic path; and a primary coil and a secondary coil disposed on the outer periphery of the core via a bobbin. ,

The primary coil and the secondary coil are axially arranged on one bobbin,

The core is a steel sheet having a cross section perpendicular to the magnetic path laminated in a D shape, and has a closed magnetic path structure,

The cross section perpendicular to the axial direction of the bin also matches the cross sectional shape of the core,

The bobbin fits into one of the longitudinal magnetic paths (hereinafter, referred to as “magnetic path A”) of the closed magnetic path, which is disposed in parallel with the closed magnetic path, and the other core is parallel to the magnetic path A. A magnetic path (hereinafter referred to as “magnetic path B”) is arranged along the outside of the primary coil and the secondary coil,

An outer edge part of each of the collar portions provided on the bobbin is linear, and a side surface corresponding to the straight side of the cross section D of the magnetic path B is applied to or close to the outer edge part. The magnetic path B is arranged so that

An ignition coil for an internal combustion engine, wherein the entire closed magnetic path of the core is housed in a cylindrical case together with the primary coil and the secondary coil.

8. The internal combustion engine according to claim 7, wherein the secondary coil is wound around a center portion of the bobbin, and the primary coil is dividedly wound at both ends of the secondary coil on a low voltage side and a high voltage side. For ignition coil.

9. A core forming a closed magnetic circuit, a primary coil and a secondary coil arranged on a part of an outer periphery of the core via a bobbin, and an ignition drive circuit for driving the primary coil and the secondary coil And an ignition coil for an internal combustion engine having a

The entire closed magnetic circuit type core and the ignition drive circuit unit are accommodated in a cylindrical case accommodating the primary coil and the secondary coil,

An ignition coil for an internal combustion engine, wherein the secondary coil is wound around a center portion of the bobbin, and the primary coil is dividedly wound around both ends of the bobbin so as to sandwich the secondary coil.

10. When the one end of the coil insertion side in the axial direction of the cylindrical case is the upper side, and the side connected to the spark plug is the lower side, the upper part of the cylindrical case is connected to an external terminal. 10. The ignition coil for an internal combustion engine according to claim 9, wherein a connector portion is formed, and an installation portion of the ignition drive circuit unit is set at a position lower than a position of the connector portion.

11. The internal combustion engine according to any one of claims 7 to 10, wherein the closed magnetic path is formed by assembling at least two divided cores into one, and a permanent magnet is arranged at a joint thereof. Ignition coil.