JP2000058349A - Ignition coil for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ignition coil or internal combustion engines, in which the occurrence of interlayer shortage between winding layers can be prevented effectively by making insulating resin to be filled penetrate easily into the central part of the coil winding. SOLUTION: Collars 24a, 24b and 24c are provided on outer periphery of a bobbin cylinder 23 of a bobbin 22. In each space separated by the collars 24a, 24b and 24c, a primary coil member 15 and a secondary coil member 16 are prepared, respectively. Four notches 25 are prepared in the collar 24a which partitions the primary coil member from the upper side and also in the collar 24c partitioning the secondary coil member from the bottom side, respectively, each in the direction from its outer peripheries towards the bobbin cylinder, at four positions which avoid cross core pieces 30 and 31. The bobbin 22 is placed between the cross core pieces 30 and 31 covered from the both upper and lower sides, and the coil member in this condition is accommodated in a case 13. In the case 13, thermosetting resin is charged and then solidified.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ignition coil for an internal combustion engine used for an internal combustion engine of an automobile or the like, and more particularly to an ignition coil for an internal combustion engine of an independent ignition type provided for each cylinder of the internal combustion engine. It is about.

[0002]

2. Description of the Related Art As an ignition coil for an internal combustion engine of this kind,
An iron core as a core is inscribed or press-fitted into a bobbin provided with a primary coil portion wound with a primary coil winding and a secondary coil portion wound with a secondary coil winding. In such a state, a thermosetting resin as an insulating resin is filled and set by heating while being set in a predetermined case body in this state.

[0003]

However, when the filled thermosetting resin does not penetrate into the wound secondary coil, that is, the center portion, good insulation performance cannot be exhibited. In the secondary coil portion that generates a high voltage, a rare short circuit may occur between the winding layers.

[0004] In addition, there is a problem that it takes time to infiltrate the thermosetting resin to the center of the secondary coil winding due to the presence of the flange of the bobbin that partitions the secondary coil.

Accordingly, an object of the present invention is to provide an ignition coil for an internal combustion engine in which an insulating resin to be filled easily penetrates into a center portion of a coil winding, thereby effectively preventing a rare short circuit between winding layers. The purpose is to provide.

[0006]

A technical means for solving the above-mentioned problem is that a plurality of flanges project radially outward on an outer peripheral surface of a cylindrical portion of a bobbin so as to be spaced in an axial direction. A formed primary coil part and a secondary coil part wound with a secondary coil winding are wound around a primary coil winding in each space part partitioned by each flange part. In the ignition coil for an internal combustion engine in which an insulating resin is filled and solidified in a case body in a state where the bobbin and the iron core are arranged in an upper open case body, at least the secondary coil portion is partitioned. One of the flanges is formed with a cutout in the direction of the cylinder from the outer peripheral edge thereof.

[0007] Further, a structure may be provided in which extended wall portions projecting outward in the axial direction from the flange portion are provided at both ends in the axial direction of the cylindrical portion.

[0008] Further, the iron core is formed in a substantially cross shape and attached so as to sandwich the bobbin from both sides, and a pair of cross iron cores forming a closed magnetic path passing from the center of the bobbin to the outer periphery on all sides. The notch,
The structure may be formed at each of four positions avoiding the cross iron core.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 10 denotes an ignition coil for an internal combustion engine, and an opening of a plug hole 12 formed in a cylinder head 11 of the internal combustion engine. It is a so-called upper-type configuration that is used by being installed on the upper part. As shown in FIGS. 2 and 3, a flat coil body 17 in which a primary coil part 15 and a secondary coil part 16 are vertically arranged in a resin case body 13 is accommodated and arranged. Have been.

As an example of the connection of the ignition coil 10, for example, the ignition coil 10 has a primary coil 1.
One end of the enameled wire wound around 5 is drawn out of the case body 13 and is electrically connected to the positive terminal of the battery of the automobile. The negative terminal of this battery is grounded. The other end of the enameled wire wound around the primary coil portion 15 is grounded via a switching element such as a power transistor provided outside the case body 13 or outside the case body 13. The switching element is controlled to be turned on / off in response to an ignition signal from an ECU or the like provided in the vehicle, whereby the primary voltage from the battery is intermittently applied to the primary coil unit 15. You. One end of the enamel wire wound around the secondary coil portion 16 is connected to the primary coil portion 15 within the case body 13.
Is electrically connected to one end of the enameled wire wound around. On the other hand, the other end of the enamel wire wound around the secondary coil portion 16 is connected to the joint member 19 in the plug hole 12.
Is electrically connected to the ignition plug 20 via the. When the primary voltage is intermittently applied to the primary coil section 15, a high voltage is induced in the secondary coil section 16 by electromagnetic induction, and this high voltage is applied to the spark plug 20, and 20 is configured to be sparked.

The coil body 17 has a structure in which a primary coil part 15 and a secondary coil part 16 are mounted on a bobbin 22, as shown in FIGS.

The bobbin 22 has a short rectangular cylindrical bobbin tube portion 2.
3 and a plurality of flange portions 24a, 24b, 24c formed on the outer peripheral surface of the bobbin cylindrical portion 23 so as to protrude radially outwardly at appropriate intervals in the axial direction, that is, in the vertical direction. At both ends in the axial direction of the bobbin cylinder portion 23, there are provided extended wall portions 26a, 26b which protrude outward in the axial direction from the upper and lower flange portions 24a, 24c, ie, vertically.

Each of the flanges 24a, 24b, 24c is formed in a substantially rectangular plate shape corresponding to the internal shape of the case body 13, and the upper and lower flanges 24a, 24c are provided with:
Substantially triangular cutouts 25 extending from the outer peripheral edge to the bobbin cylinder 23 are formed at four positions at regular intervals in the circumferential direction.

As shown in FIGS. 2 and 3, the secondary coil portion 16 is provided with an enamel wire as a secondary coil winding in a space defined by both central and lower flange portions 24b and 24c. It is formed in a substantially disk shape by winding.

The enamel wire used for the secondary coil portion 16 has a general configuration in which an enamel paint is applied to the surface of a copper wire having a substantially circular cross section. More specifically, an enameled wire having a wire diameter of 0.04 to 0.1 mm is 800
It is preferable to form the secondary coil portion 16 by winding 0 to 15000 times.

As shown in FIG. 2 and FIG. 3, the primary coil portion 15 is formed in a space defined by upper and central flange portions 24a and 24b, and has a substantially rectangular shape having a vertically long section as a primary coil winding. The enameled wire formed by applying an enamel paint to the surface of the rectangular strip-shaped copper wire is wound into a substantially disk shape by being stacked in the thickness direction thereof.

The surface of the enameled wire used for the primary coil portion 15 is coated with a heat-welding paint, and can be wound under a heated condition or heated after being wound. As a result, the enameled wire is solidified in a form wound in a substantially disk shape. More specifically,
A rectangular strip-shaped enameled wire rolled 1:15 to 1:30 is wound 90 to 180 times in the radial direction, and the primary coil portion 15 is wound.
Should be formed.

Here, the reason why a rectangular belt-shaped enameled wire is used for the primary coil portion 15 will be described.

For example, when an enameled wire having a substantially circular cross section is used, no matter how densely the enameled wire is wound, a useless space is created between the wound enameled wires. This leads to an increase in the size of the primary coil portion, and also causes the heat generated there to be dissipated.

On the other hand, as in the case of the ignition coil 10 of the present embodiment, when enamel wires are wound in a rectangular band shape and wound in such a manner that the enamel wires are stacked in the thickness direction, the enamel wires are separated by a gap. It is possible to tightly wind the coil, and to make the primary coil portion 15 smaller, and furthermore, to make the ignition coil 10 thinner and smaller in diameter, as well as to improve the heat transfer of the heat generated there, and to improve the heat dissipation. It will be excellent.

Here, the primary coil section 15 and the secondary coil section 16 are arranged in a stacked manner such that their respective cores are aligned with the axis of the bobbin cylinder 23, and the flat coil body 1
7 is configured.

In this case, the flat coil body 17 preferably has a height of 10 to 25 mm and a ratio of the height to the width of 1: 2 to 1: 6. The reason why the upper limit of the height dimension is set to 25 mm is that if it is larger than this, it is generally easy to interfere with other intake / exhaust system parts and the like near the cylinder head 11. This is due to restrictions due to the size of accessories such as connectors and switching elements provided on the body 13.

Then, both ends of the enamel wire wound on the primary coil portion 15 and both ends of the enamel wire wound on the secondary coil portion 16 are respectively drawn out of the coil body 17 and One end of the enamel wire of the side coil portion 15 and one end of the enamel wire of the secondary coil portion 16 are electrically connected to each other at the position of the outer peripheral edge of the flange portion 24b (not shown).

As shown in FIGS. 2 to 5, a pair of cross iron cores 30, 31 constituting an iron core are attached to the upper and lower surfaces of the coil body 17 thus configured.

Each of the cross core portions 30 and 31 has a substantially U-shaped core portion 30a, 30b, 3 formed by laminating electromagnetic steel plates.
It is formed by combining 1a and 31b in a substantially cross shape such that they intersect at their middle part.

The core 30b disposed on the lower side at the intersection of each of the cores 30a and 30b of the upper cross core 30 has a core 30 on the lower side of the intersection.
A triangular prism-shaped core portion 30c having a tapered surface inclined downward in the longitudinal direction of b is formed. The core portion 30c is configured to be inserted into the bobbin tube portion 23 from above with the cross iron core portion 30 attached to the upper surface side of the coil body 17.

On the other hand, the lower cross core 31 has an upside-down shape with respect to the upper cross core 30, and the upper core 31b is disposed at the intersection of the cores 31a and 31b. A core part 31c facing the core part 30c is formed on the upper surface side of.

The core portion 31c is also configured to be inserted from below into the bobbin tube portion 23 with the cross iron core portion 31 attached to the lower surface side of the coil body 17.

When these cross iron cores 30 and 31 are attached to the upper and lower surfaces of the coil body 17, respectively, four upward end faces of the iron cores 31a and 31b located on the lower side and each of the upper end faces located on the upper side. The four downward end surfaces of the iron core portions 30a and 30b are configured to abut on the outer periphery of the coil body 17.

Then, as shown in FIGS. 3 and 4,
The cutout portions 25 are formed at positions avoiding the cross iron core portions 30 and 31, respectively.

Further, as shown in FIG.
Opposing tapered surfaces of c and 31c are structured so as to be arranged in parallel with each other in the bobbin cylindrical portion 23 with an interval capable of accommodating the permanent magnet 33.

The cross iron cores 30 and 31 form four closed magnetic paths that pass from the center of the coil body 17 to the outer periphery in all four directions.

The cross iron cores 30 and 31 have a thickness of 0.1 mm as the iron cores 30a, 30b, 31a and 31b.
It is good to use what laminated | stacked the silicon plywood of 1-0.5 mm, formed in the substantially U-shape, and formed so that the total cross-sectional area of four closed magnetic paths extended outward from the center might be 100-324 mm < ² >.

In the state where the two cross iron cores 30 and 31 are attached to the coil body 17, as described above, each core 30
A gap having a predetermined interval is formed between the magnets c and 31c, and a permanent magnet 33 that magnetically reversely biases the cross iron cores 30 and 31 is provided in the gap.

As shown in FIGS. 2 and 3, the case body 13 is formed in a flat box shape having a square bottom surface and an open top, and has four substantially L-shaped ridges on its inner bottom surface 13a. The portions 13b are formed so as to face each other with a predetermined space between them, so that the cross-shaped positioning groove 13 for fitting and positioning the cross-shaped core portion 31 is formed.
c is formed.

As shown in FIGS. 1 and 2, a connecting portion 34 having a slightly tapered lower end is provided at the center of the lower surface of the case body 13 so as to protrude downward.

Here, the reason why the connecting portion 34 is formed at the center of the case body 13 will be explained. The reason is that abnormal vibration of the case body 13 (resonance caused by vibration of the internal combustion engine and the connection portion 34 The case body 1)
This is to extend the life of the product such as 3rd.

Next, a method of assembling the ignition coil 10 will be described.
Each of the cross iron core portions 30 and 31 is sandwiched from both upper and lower sides of a coil body 17 provided with the secondary coil portion 16.
In this state, the cross iron core 31 on the lower surface side is fitted into the positioning groove 13 c in the case body 13, and the coil body 17 is housed in the case body 13 in a positioning manner.

After the coil body 17 and the cross iron cores 30 and 31 are accommodated in the case body 13, the coil body 1
A thermosetting resin as a liquid insulating resin is injected and filled under vacuum in the case body 13 so that the case 7 is immersed, and is solidified by heat treatment. Thus, the ignition coil 10 in which the coil body 17 is integrally fixed to the case body 13 is configured.

The ignition coil 10 according to the present embodiment is configured as described above, and each notch 25 is formed in each of the upper and lower flanges 24a and 24c which partition the primary coil 15 and the secondary coil 16. The primary coil portion 15 and the secondary coil portion 1 are formed through these cutout portions 25.
The thermosetting resin injected into the winding layers at the center of each enameled wire of No. 6 is easily guided, and here, the winding layers reaching the center of the primary coil portion 15 and the secondary coil portion 16 are also introduced. The thermosetting resin sufficiently penetrates, and in particular, the occurrence of rare short between the winding layers in the secondary coil portion 16 can be effectively prevented.

At this time, since the extending walls 26a and 26b are provided at the upper and lower ends of the bobbin cylinder 23 in a protruding manner, respectively, between the upper surface of the flange 24a and the cross iron core 30 and the flange 30a. Sufficient gaps can be secured between the lower surface of the base 24c and the cross core 31, respectively, and an insulation distance is secured here, and the thermosetting resin is supplied through the gaps to the primary coil portion 15 or the secondary coil portion. It can be easily penetrated into the central part of the part 16, so that the permeation time can be further reduced, and from this point, the occurrence of rare short between the winding layers can be more effectively prevented.

Further, each notch 25 has a cross iron core 30,
Since they are formed at four positions avoiding 31, respectively, the guide of the injected thermosetting resin to the center portion of the primary side coil portion 15 or the secondary side coil portion 16 can be more smoothly performed. It can be easily penetrated into the central part of the primary side coil part 15 and the secondary side coil part 16, so that the permeation time can be further reduced, and the occurrence of rare short between the winding layers can be more effectively prevented. .

Since the thermosetting resin sufficiently penetrates between the winding layers of the primary coil section 15 and the secondary coil section 16, the primary coil section 15 and the secondary coil section 16 are prevented from being out of shape. Certainty of positioning and fixing can be achieved.

Further, when an enamel wire having a substantially circular cross section is wound like the secondary coil portion 16, as shown by the imaginary line in FIG. Although it may occur, a pair of cross iron cores 30,
In this system, the coil body 17 is attached so as to sandwich the coil body 17 from both upper and lower sides. The distortion deformation can be effectively prevented by the cross iron core portion 31, and the secondary coil portion 16 can be effectively prevented from becoming uneven.

Also, a substantially disk-shaped primary coil portion 15,
Since the coil body 17 is formed by laminating the substantially coiled secondary side coil portion 16, it is possible to obtain secondary energy large enough to ignite the air-fuel mixture in the cylinder of the internal combustion engine. The shape of the coil body 17 is a flat shape formed by laminating the primary side coil part 15 and the secondary side coil part 16, so that the height dimension is reduced and Interference between the installed ignition coils 10 can also be prevented.

In the above-described embodiment, the primary coil portion 15 has a structure in which a rectangular band-shaped enamel wire is wound, but like the secondary coil portion 16, an enamel wire having a substantially circular cross section is used. The structure which winds may be sufficient. Also in this case, the cross iron core 30 can effectively prevent distortion deformation in the spreading direction of the flange 24a.

[0047]

As described above, according to the ignition coil for an internal combustion engine of the present invention, at least one of the flanges partitioning the secondary coil is formed with a notch in the direction of the cylinder from the outer peripheral edge thereof. This has the advantage that the insulating resin filled through the notch easily penetrates to the center of the coil winding, and the occurrence of rare short between the winding layers can be effectively prevented. .

In addition, if the cylindrical portion is provided with extended walls protruding outward from the flange in the axial direction at both ends in the axial direction, the infiltration path of the insulating resin is more effective. And it is possible to more easily penetrate into the center of the coil winding, and it is possible to more effectively prevent the occurrence of a rare short between the winding layers.

Further, the iron core is formed in a substantially cross shape and is attached so as to sandwich the bobbin from both sides, and comprises a pair of cross iron cores forming a closed magnetic path passing from the center of the bobbin to the outer periphery on all sides. If the notch portion is formed at each of the four positions avoiding the cross iron core portion, the infiltration path of the insulating resin can be more effectively secured, and it is easier to reach the center of the coil winding. In addition, there is an advantage that distortion deformation in the spreading direction of the flange portion can be prevented, and the occurrence of a rare short circuit between the winding layers can be more effectively prevented.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a mounted state of an ignition coil for an internal combustion engine according to an embodiment of the present invention.

FIG. 2 is a sectional view showing the ignition coil.

FIG. 3 is an exploded perspective view of the ignition coil.

FIG. 4 is a plan view of a bobbin.

FIG. 5 is a perspective view of a cross iron core.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Ignition coil 13 Case body 15 Primary coil part 16 Secondary coil part 17 Coil body 22 Bobbin 23 Bobbin cylinder part 24a Flange part 24b Flange part 24c Flange part 25 Notch part 26a Extension wall part 26b Extension wall part 30 Cross Iron core part 31 Cross iron core part

Claims (3)

[Claims] A plurality of flanges are formed on an outer peripheral surface of a cylindrical portion of a bobbin so as to be radially outwardly spaced apart in an axial direction of the cylindrical portion, and a primary space is formed in each space portion partitioned by the flanges. A primary coil portion wound with a side coil winding and a secondary coil portion wound with a secondary coil winding are provided, and the bobbin and the iron core are arranged in a case body that is open at the top. In the state, in the ignition coil for an internal combustion engine in which the insulating resin is filled and solidified in the case body, at least one flange portion partitioning the secondary coil portion,
An ignition coil for an internal combustion engine, wherein a cutout portion in the direction of the cylindrical portion is formed from an outer peripheral portion thereof. 2. The internal combustion engine according to claim 1, wherein extending end portions protruding outward in the axial direction from the flange portion are provided at both ends in the axial direction of the cylindrical portion. For ignition coil. 3. A pair of cruciform cores, each of which is formed in a substantially cross shape and is attached so as to sandwich the bobbin from both sides, and forms a closed magnetic path passing from the center of the bobbin to four sides around the outside. The ignition coil for an internal combustion engine according to claim 1 or 2, wherein the notch is formed at each of four positions avoiding the cross iron core.