JPH11111548A - Stick-type ignition coil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain appropriate values in the outer diameter of central core and thickness of outer core, when the outer diameter is limited to 24 mm or less, and to generate required voltage without the use of a permanent magnet. SOLUTION: A stick-type ignition coil 1 is 24 mm or less in outer diameter w of coil part, an integrated value of the turning number of coil and the amperage value of an applied current is 700 to 2500, and the outer diameter of an outer core 8 is 20 to 24 mm. The diameter x mm of a core 3 and thickness y mm of the core 8 are provided to satisfy a formula y=(11/50)x-a (where 6.0<=x<=11.0, 0.5<=y<=1.5, 0.6<=a<=1.3). As a result, the outer diameter w can be set to 24 mm or less, and a voltage of about 25 to 40 kV can be generated even when no permanent magnet is used for the core 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stick type ignition coil mounted in a plug hole of an engine and generating a high voltage required for ignition.

[0002]

2. Description of the Related Art A conventional stick type ignition coil (hereinafter, referred to as a "stick type ignition coil")
As an ignition coil, a technique disclosed in Japanese Patent Application Laid-Open No. 8-213259 is known. As shown in FIG. 4, this ignition coil is provided inside a cylindrical housing J1.
A rod-shaped central core J2, a secondary coil J4 wound around a secondary spool J3 disposed around the outer periphery thereof, and a primary coil J6 wound around a primary spool J5 disposed around the periphery thereof.
And an outer peripheral core J7 disposed on the outer periphery thereof. Then, each gap is filled with a thermosetting resin J8 to ensure the electrical insulation and mechanical strength inside.

Since this ignition coil is mounted in a plug hole of an engine, it must be formed in a very limited space with an outer diameter of the coil portion of 24 mm or less, and the performance as an ignition coil is ensured. For this purpose, permanent magnets J9 and J10 having polarities opposite to the excitation poles of the center core J2 are mounted on both ends of the center core J2.

[0004]

The permanent magnets J9 and J10 mounted on both ends of the center core J2 use rare earth magnets such as neodymium which generate a high magnetic force in a small space. Magnets J9, J10
Also increases the cost of the ignition coil. In other words, since the ignition coil is installed in the plug hole of the engine, it must be configured in a very limited space. Therefore, to meet the required voltage, the permanent magnets J9 and J10 must be installed. I was

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and has as its object to provide the optimum value of the diameter of the center core and the thickness of the outer core under the constraint that the outer diameter of the coil portion is 24 mm or less. And to provide an ignition coil that can generate a required voltage without using a permanent magnet.

[0006]

[Means for Solving the Problems]

[Means of Claim 1] In the ignition coil, when the diameter xmm of the center core and the thickness ymm of the outer peripheral core satisfy claim 1, the outer diameter of the coil portion is 24 mm or less, and The required voltage of the engine can be generated without using a permanent magnet. As described above, since the required voltage can be generated without using a permanent magnet, the cost of the ignition coil can be reduced.

[0007]

Next, embodiments of the present invention will be described with reference to examples and modifications. [Embodiment] An embodiment will be described with reference to FIGS.
FIG. 1 is a sectional view of the ignition coil, and FIGS. 2 and 3 are graphs showing the results of magnetic analysis.

The ignition coil 1 is mounted in a plug hole formed for each cylinder of the engine (not shown), and is electrically connected to a spark plug (not shown). The diameter W is set to 24 mm or less. The ignition coil 1 includes a cylindrical housing 2 made of a resin material.
From the center outward, a central core 3, a secondary spool 4, a secondary coil 5, a primary spool 6, a primary coil 7, and an outer core 8 are housed. 9 (for example, epoxy resin).

The center core 3 has a cylindrical shape.
It is provided by laminating thin silicon steel sheets in the lateral direction (the direction perpendicular to the axial direction). The center core 3 is positioned on the inner wall of the secondary spool 4, and no permanent magnet is attached to both ends of the center core 3. The secondary spool 4 is
The spool for forming the secondary coil 5 is positioned on the inner wall of the primary spool 6, and is formed of a resin material. 2
The secondary coil 5 is formed by winding a very thin coil wire with insulation coating around the outer periphery of the secondary spool 4 and is provided in a cylindrical shape, and is electrically connected to a high voltage terminal 12 described later.

The primary spool 6 is a bobbin for forming the primary coil 7, is positioned on the inner wall of the housing 2 and the outer core 8, and is formed of a resin material. The primary coil 7 is insulated and coated, and is provided in a cylindrical shape by winding a coil wire thicker than the coil wire of the secondary coil 5, and is electrically connected to an input terminal 11 described later.

The outer core 8 is mounted in contact with the inner wall of the housing 2. The outer core 8 is formed by rolling a thin silicon steel sheet into a cylindrical shape so as to form a slit for insulation at the start and end of winding. The thermosetting insulating resin 9 enters a gap in the housing 2 in which the components are assembled, ensures electrical insulation between the components, solidifies and integrates the components, and is damaged by vibration. It is to prevent.

A connector 10 for connecting an ignition coil is provided at the upper end of the housing 2 so as to protrude from the plug hole, and an input terminal 11 for supplying a control signal to the primary coil 7 is insert-molded on the connector 10. Have been. A switching circuit (not shown) for supplying a control signal to the input terminal 11 includes an ignition coil 1
Is located outside.

The high-voltage terminal 12 is insert-molded or press-fitted into the lower end of the housing 2 and is electrically connected to the spring 13. This spring 13
A high voltage generated in the secondary coil 5 is applied to the ignition plug via the high voltage terminal 12 and the spring 13 when the ignition coil 1 is mounted in the plug hole and is electrically connected to the ignition plug. A plug cap 14 made of rubber is mounted on the lower end opening of the housing 2, and the plug cap 14 is mounted on the ignition plug.

The ignition coil 1 adopting the above configuration is provided so as to satisfy the following conditions. First, the diameter dimension xmm of the central core 3 and the thickness dimension ym of the outer peripheral core 8
2 and 3 show magnetic analysis graphs obtained by analyzing the generated voltage in relation to m. 2 and FIG.
The number of turns of the secondary coil 7 is 230T, the number of turns of the secondary coil 5 is 17480T, and the current applied to the primary coil 7 is 6.
It is an analysis result in 5A. FIG. 2 shows an example in which an iron tube is used as a plug tube, and FIG. 3 shows an example in which an aluminum tube is used as a plug tube.

As shown in FIGS. 2 and 3, when one of the center core 3 and the outer core 8 is magnetically saturated at a predetermined voltage, a substantially L-shaped characteristic is generated. The vicinity of the inflection point is the least wasteful relation ratio between the diameter of the central core 3 and the thickness of the outer core 8, and the inflection point has a generated voltage of 25 k
Within the range of V to 40 kV, almost y = (11/5)
0) Appears near x-a (where 0.6 ≦ a ≦ 1.3). Then, various experiments were repeated, and the diameter xmm of the center core 3 and the thickness ymm of the outer core 8 were: y = (11/50) x-a, 6.0 ≦ x ≦ 11.0, By providing such that 5 ≦ y ≦ 1.5 and 0.6 ≦ a ≦ 1.3, 25 kV to 40 k
It has been found that V generation voltage is obtained.

In particular, the diameter xmm of the center core 3 and the thickness ymm of the outer core 8 are provided so as to satisfy 8.0 ≦ x ≦ 11.0 and 0.8 ≦ y ≦ 1.5. Has been found to be able to generate 30 kV or more.

On the other hand, the above-mentioned characteristic is satisfied because the amperage A of the current applied to the primary coil 7 and the number of turns T of the coil wire of the primary coil 7 are the ampere-ampere.
It has been found that the turn A × T is in the range of 700 to 2500, preferably in the range of 800 to 2000. As an optimal example, in this embodiment, the amperage of the current applied to the primary coil 7 is 6.5 A, and the number of turns of the coil wire of the primary coil 7 is set to 230T, which is an integrated value. Ampere turn A × T is about 150
0.

The magnetic saturation of the outer core 8 is affected by the cross-sectional area, and is affected not only by the thickness but also by the diameter of the outer core 8. And, it was found that the above-mentioned characteristics are satisfied when the outer diameter of the outer peripheral core 8 is provided in a range of 20 to 24 mm. In this embodiment, the housing 2 having a thickness of about 0.5 to 1 mm exists on the outer periphery of the outer peripheral core 8, and in this embodiment, the outer diameter dimension W of the coil portion is
For example, it is provided at about 22 to 23.5 mm,
Due to such restrictions, the outer diameter of the outer peripheral core 8 of the present embodiment is provided within a range of 20 to 23 mm.

Since the ignition coil 1 is provided so as to satisfy the above conditions, the outer diameter dimension W of the coil portion is 2 mm.
Even within the constraint of 4 mm or less, the required voltage of the engine can be generated without using a permanent magnet for the center core 3. Since the required voltage can be generated without using a permanent magnet, the cost of the ignition coil can be reduced.

[Modification] In the above embodiment, the outer core 8
Although the example in which the housing 2 is provided on the outer periphery of the above is shown, the outer core 8 may have a housing function without using the housing 2. In this case, rubber is baked on the slit of the outer peripheral core 8 to seal the inside. As described above, when the housing 2 does not exist on the outer periphery of the outer core 8, the outer core 8
Is provided in the range of 22 to 23.5 mm.

[Brief description of the drawings]

FIG. 1 is a sectional view of an ignition coil (Example).

FIG. 2 is a graph showing a result of a magnetic analysis when an iron tube is mounted.

FIG. 3 is a graph showing a result of a magnetic analysis when an aluminum tube is mounted.

FIG. 4 is a sectional view of an ignition coil (conventional example).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ignition coil 2 Housing 3 Center core 5 Secondary coil 7 Primary coil 8 Outer core

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Keiichi Okazaki 1-1-1, Showa-cho, Kariya-shi, Aichi Prefecture Inside DENSO Corporation

Claims (6)

[Claims] 1. A central core having a cylindrical shape, a primary coil and a secondary coil disposed on the outer periphery of the central core, and disposed on an outer periphery of the primary coil and the secondary coil for axial insulation. A stick-shaped ignition coil having an outer diameter of a coil portion of 24 mm or less and being installed in a plug hole of an engine, wherein the central core is a permanent core. The magnet is not mounted, and the diameter xmm of the central core and the thickness ymm of the outer core are as follows: y = (11/50) x-a, 6.0 ≦ x ≦ 11.0, A stick-type ignition coil, satisfying 5 ≦ y ≦ 1.5 and 0.6 ≦ a ≦ 1.3. 2. The stick type ignition coil according to claim 1, wherein 8.0 ≦ x ≦ 11.0 and 0.8 ≦ y ≦ 1.5 are satisfied. 3. The stick type ignition coil according to claim 1, wherein an integrated value of an amperage A of a current applied to the primary coil and a turn number T of a coil wire of the primary coil. A stick-type ignition coil wherein a certain ampere-turn A × T is in the range of 700-2500. 4. The stick-type ignition coil according to claim 1, wherein an integrated value of an amperage A of a current applied to the primary coil and a turn number T of a coil wire of the primary coil. A stick-type ignition coil wherein a certain ampere-turn A × T is in the range of 800-2000. 5. The stick-type ignition coil according to claim 1, wherein an outer diameter of the outer peripheral core is 22 to 23.5 mm when a housing is not present on an outer periphery of the outer peripheral core. A stick-type ignition coil characterized by being inside. 6. The stick type ignition coil according to claim 1, wherein an outer diameter of the outer peripheral core in a case where a housing is present on an outer periphery of the outer peripheral core is within a range of 20 to 23 mm. A stick-type ignition coil, characterized in that: