JP2002359129A - Manufacturing method of ignition coil for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of an ignition coil which can restrain eddy current on a circumference generated in a second core 5 itself in an ignition coil 1 disposed inside a plug tube of a DLI-type internal combustion engine. SOLUTION: In a manufacturing method of an ignition coil composed of a first core 4, the coil is disposed inside a tubular plug tube of a conductive material in an internal combustion engine, directly connected to an ignition plug and is a rod-like lamination body formed by laminating a plurality of plane-like magnetic materials. A primary coil 2 and a secondary coil 3 are disposed in an outer circumference of the first core 4. The second core 5 has a tubular part for storing the primary coil 2, the secondary coil 3 and the first core 4 inside and is formed of a magnetic material forming a magnetic path together with the first core 4. A tubular part of the second core 5 is formed by bending one magnetic material plane almost tubular, and has a clearance in a tubular direction formed when both ends of the plane are mutually jointed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing an ignition coil for a DLI internal combustion engine.

[0002]

2. Description of the Related Art As a conventional technique, a cap and a rotor of a distributor are abolished, and one ignition coil (ignition coil) is used for two cylinders to simultaneously operate a cylinder in an exhaust process and a compression (ignition) cylinder. There is a DLI (Distributor-less Ignition) system that is ignited.

[0003]

However, the above-mentioned DL
When the ignition coil of the I-system is provided in the plug tube of the internal combustion engine, there is a problem that an eddy current is generated by the leakage magnetic flux passing through the plug tube and the output of the ignition coil is reduced.

[0004] In addition, the outer periphery of a generally rod-shaped first core is
By providing the cylindrical second core in the ignition coil around which the secondary coil and the secondary coil are wound, it is possible to reduce the leakage magnetic flux passing through the plug tube. Eddy current is generated, and the output of the ignition coil is reduced.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method of manufacturing an ignition coil for an internal combustion engine, in which a slit is provided in a second core to suppress an eddy current on a circumference generated in the second core itself. Is to do.

[0006]

According to the first aspect of the present invention, a flat magnetic material is disposed in a cylindrical plug tube made of a conductive material of an internal combustion engine and directly connected to an ignition plug. A first core, which is a multilayer body formed by laminating a plurality of round bars, a primary coil and a secondary coil disposed on the outer periphery of the first core, and the primary coil, the secondary coil, and the In a method for manufacturing an ignition coil having a tubular portion for accommodating a first core and a second core made of a magnetic material forming a magnetic path together with the first core, the tubular portion of the second core is A method for manufacturing an ignition coil for an internal combustion engine, wherein a flat plate made of a magnetic material is bent into a substantially cylindrical shape to form a cylindrical gap formed when both ends of the flat plate are abutted with each other.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described based on embodiments with reference to the drawings.

[First Embodiment] FIGS. 1 to 5 show a first embodiment of the present invention, and FIGS.
FIG. 4 is a diagram showing an ignition coil for an internal combustion engine mounted on an LI system internal combustion engine, and FIG. 4 is a diagram showing a DLI system internal combustion engine.

An ignition coil for an internal combustion engine (hereinafter abbreviated as an ignition coil) 1 is a cylindrical member made of a conductive material such as iron or aluminum provided between banks 12 formed on a cylinder cover of a DLI type internal combustion engine 11. It is directly connected to a spark plug 14 provided in a plug tube 13. In this embodiment, a high voltage is supplied to one ignition plug 14 for one ignition coil 1.

The ignition coil 1 comprises a primary coil 2,
It comprises a secondary coil 3 and an iron core 10. Primary coil 2
Is wound around a bobbin (not shown) provided on the outer periphery of the first core 4 of the iron core 10 described later. One terminal of the primary coil 2 is connected to a vehicle-mounted battery (not shown) via a terminal 21. The other end of the primary coil 2 is connected to an igniter (not shown) via a terminal 21, and the igniter switches between an energized state (I ₁ = 6.5 A) and an energized stopped state.

The secondary coil 3 is wound around a bobbin (not shown) which is thinner than the primary coil 2 and which is disposed on the outer periphery of the first core 4. This secondary coil 3
One terminal is connected to one terminal of the primary coil 2, and the other terminal is connected to the spark plug 14. The secondary coil 3 generates a high voltage when the primary coil 2 is de-energized from the energized state.

The iron core 10 is excited when the primary coil 2 is energized and stores magnetic energy, and when the energization of the primary coil 2 is stopped, the core 10 emits the stored magnetic energy when energized. An induced electromotive force is generated in the secondary coil 3. The iron core 10 is disposed in the first core 4, the second core 5 that forms a closed magnetic circuit with the first core 4, and the air gap between the first core 4 and the second core 5. It is composed of a permanent magnet 6.

The first core 4 is formed by punching a magnetic material (for example, soft iron) into a flat plate shape by a press or the like, and then laminating a plurality of press-molded products to form a round bar shape. Things. The first core 4 has a primary coil 2 and a secondary coil 3 wound around the outer periphery.

One end 41 of the first core 4 is
It is located on the inner periphery of one end of the core 5 and is opposed to one end of the second core 5 via an air gap. The other end 42 of the first core 4 is located on the inner periphery of the other end of the second core 5 and is connected to the other end of the second core 5.

The second core 5 has a space inside so that the primary coil 2, the secondary coil 3 and the first core 4 can be accommodated therein. And the second core 5 is a cylindrical core 51,
And annular cores 52 and 53.

The cylindrical core 51 is a cylindrical portion of the present invention.
The cylindrical core 51 is formed by bending a single flat plate made of a magnetic material (for example, soft iron) into a substantially cylindrical shape, and has a cylindrical gap (not shown) formed when both ends of the flat plate are butted together. : Corresponding to the slit of the present invention). The cylindrical core 51 is disposed in parallel with and near the inner periphery of the plug tube 13. The inner periphery of one end 54 of the cylindrical core 51 is directly connected to the outer periphery of the annular core 52. The inner periphery of the other end 55 of the cylindrical core 51 is directly connected to the outer periphery of the annular core 53.

The annular core 52 is made of a magnetic material (for example, soft iron).
Is formed by punching a flat plate made of metal into an annular shape with a press or the like, and then laminating a plurality of press-formed products and press-caulking. This annular core 52 is provided on the outer periphery of one end 41 of the first core 4. The inner periphery of the annular core 52 is connected to one end 41 of the first core 4 via an air gap. The outer periphery of the annular core 52 is
One of the first ends 54 is fitted and directly connected. The annular core 52 has a hole (not shown) through which one terminal and the other terminal of the primary coil 2 are inserted.

The annular core 53 is made of a magnetic material (for example, soft iron).
Is formed by punching a flat plate made of metal into an annular shape with a press or the like, and then laminating a plurality of press-formed products and press-caulking. This annular core 53 is arranged on the outer periphery of the other end 42 of the first core 4. The inner periphery of the annular core 53 is fitted to the other end 42 of the first core 4 and directly connected. The outer periphery of the annular core 53 is
Are fitted directly to the other end 55 and are directly connected. The annular core 53 has a hole (not shown) through which the other end of the secondary coil 3 is inserted.

The permanent magnet 6 applies a bias magnetic flux to the closed magnetic circuit to improve the voltage generated in the secondary coil 3. The permanent magnet 6 is formed in an annular shape, and a rare earth magnet such as a neodymium magnet or a rare earth-cobalt magnet is used. The permanent magnet 6 is disposed so as to be fitted in an air gap between one end 41 of the first core 4 and the inner periphery of the annular core 52 of the second core 5.

First core 4, cylindrical core 51 and annular core 5 having primary coil 2 and secondary coil 3 wound around outer periphery
The assembled body in which the second core 5 composed of 2, 53 and the permanent magnet 6 are assembled is housed in an ignition coil case 7 made of a resin, and injection molding resin (not shown) is injected and hardened to form an ignition coil. 1 is formed. A terminal 21 protrudes from one end of the ignition coil case 7, and a rubber plug cap 15 that covers a terminal of the ignition plug 14 is connected to the other end.

[Operation of the First Embodiment] The operation of the ignition coil 1 of this embodiment will be described with reference to FIGS. When a key switch (not shown) is turned on, one terminal of the primary coil 2 and the secondary coil 3 is connected to the vehicle battery. The igniter generates an ignition signal such that the primary coil 2 switches from the energized state to the energized stop state at the ignition timing according to the operating state of the internal combustion engine such as the crank angle.

When the primary coil 2 is energized, the second core 5 composed of the first core 4, the cylindrical core 51 and the annular cores 52 and 53 is excited, and the first core 4, the cylindrical core 51 and the annular core 52 are excited. Magnetic flux passing through the second core 5 composed of 53 is generated.

The magnetic flux passing through the second core 5 composed of the first core 4, the cylindrical core 51 and the annular cores 52, 53 is as follows.
With the bias magnetic flux of the permanent magnet 6 disposed in the air gap between the one end 41 of the first core 4 and the inner circumference of the annular core 52, even if the generated magnetic flux of the primary coil 2 is small, Large magnetic energy is stored in 10.

When the primary coil 2 is switched to an energized state by the igniter at the ignition timing, the magnetic energy stored in the iron core 10 is released, and an induced electromotive force is generated in the secondary coil 3. The secondary coil 3 is thinner than the primary coil 2 and is wound around the outer periphery of the first core 4 in large numbers. Therefore, a high voltage (generated voltage) is generated in the secondary coil 3 by the induced electromotive force. Then, the high voltage generated in the secondary coil 3 is applied to the spark plug 14 and generates a spark discharge in the combustion chamber 16 of the internal combustion engine. Thereafter, the energization of the primary coil 2 and the stop of the energization are repeated by the igniter to perform the above operation.

Here, the primary coil 2 is energized and the core 1
0 when the magnetic flux passing through the second core 5 is generated.
There is a possibility that the magnetic flux leaks into the plug tube 13 disposed on the outer periphery of the plug tube 1.

However, in the present embodiment, the cylindrical core 51 of the second core 5 is disposed along the inner peripheral surface of the plug tube 13, and a gap in the cylindrical direction is formed in the cylindrical core 51. I have. Thereby, the magnetic flux that has passed through the annular cores 52 and 53 from the first core 4 passes through the cylindrical core 51 of the second core 5 without leaking much to the plug tube 13. For this reason, the leakage magnetic flux passing through the plug tube 13 is significantly reduced as compared with the ignition coil having no cylindrical core. As described above, since the leakage magnetic flux passing through the plug tube 13 is significantly reduced, the plug tube 1
The eddy current does not flow through 3 and the eddy current on the circumference hardly flows through the cylindrical core 51 of the second core 5.

[Effects of the First Embodiment] As described above, in the ignition coil 1 of the present embodiment, a decrease in the magnetic energy stored in the iron core 10 can be prevented, so that the occurrence of eddy current loss can be suppressed. Therefore, it is possible to suppress a decrease in the induced electromotive force generated in the secondary coil 3 of the ignition coil 1, so that a desired high voltage (generated voltage) generated in the secondary coil 3 is applied to the ignition plug 1.
4 can be applied.

Therefore, the secondary coil 3 of the ignition coil 1
Is slightly lower than the voltage generated in the secondary coil of the ignition coil of the comparative example (see the graph of FIG. 5). That is, the voltage generated by the secondary coil 3 can be significantly improved as compared to the voltage generated by the ignition coil having no cylindrical core.

FIG. 5 is a graph showing the voltages generated in the secondary coils of the ignition coil 1 of the present embodiment and the ignition coil of the comparative example, respectively. In addition, a shows the ignition coil which is arrange | positioned at the place where there is no component made of a conductive material near in the structure of this Example. "b" indicates the ignition coil 1 of this embodiment disposed in the plug tube 13.

By adopting a cylindrical core 51 having a gap as the cylindrical portion of the second core 5, the joint of the second core 5 is positively utilized as a slit. The eddy current on the circumference generated in the core 51 itself can be suppressed.

[Second Embodiment] FIG. 6 shows a second embodiment of the present invention and is a view showing an iron core portion of an ignition coil for an internal combustion engine.

In this embodiment, a cylindrical core 51 having a gap in the cylinder direction as in the first embodiment, and disk-shaped cores 56 and 57 fitted on the inner circumferences of both ends of the cylindrical core 51 are formed. Two cores 5 are configured. In the present embodiment, rectangular parallelepiped permanent magnets 63, 64 are provided between both connecting portions of both ends of the first core 43 and the inner surfaces of the disc-shaped cores 56, 57, which are located in the axial direction of the first core 43. It is arranged.

[Third Embodiment] FIG. 7 shows a third embodiment of the present invention and is a diagram showing an iron core portion of an ignition coil for an internal combustion engine.

In the present embodiment, the first core 43 of the second embodiment is used.
Is changed to a round bar-shaped first core 44. Also,
Disc-shaped permanent magnets 65, 66 are disposed between both ends of the first core 44 and the inner surfaces of the disc-shaped cores 56, 57 between the two connecting portions located in the axial direction of the first core 44. Have been.

[Modification] In the present embodiment, the permanent magnets 6 are arranged in the closed magnetic circuit. However, the permanent magnets may not be provided in the closed magnetic circuit. In the second and third embodiments, the first core 4 and the second core 5
The permanent magnets are provided between the core connecting portions at both ends of the first core, but the permanent magnets are provided only between one of the core connecting portions at both ends of the first core 4 and the second core 5. You may.

In this embodiment, a cylindrical core 51 formed by bending a single flat plate made of a magnetic material into a substantially cylindrical shape is employed as the cylindrical portion of the second core 5. As the cylindrical portion, a polygonal cylindrical core or a cylindrical core partially having a gap may be employed. In this embodiment, 1
Although one ignition coil 1 supplies power to one ignition plug 14, one ignition coil 1 may supply power to two or more ignition plugs 14.

[Brief description of the drawings]

FIG. 1 is a perspective sectional view showing an ignition coil for an internal combustion engine (first embodiment).

FIG. 2 is a side view showing an iron core portion of the ignition coil for the internal combustion engine (first embodiment).

FIG. 3 is a sectional view showing an iron core portion of an ignition coil for an internal combustion engine (first embodiment).

FIG. 4 is a partial sectional view showing a DLI type internal combustion engine (first embodiment).

FIG. 5 is a graph showing voltages generated in secondary coils of the present example and a comparative example (first example).

FIG. 6 is a partial cross-sectional view illustrating an iron core of an internal combustion engine ignition coil (second embodiment).

FIG. 7 is a partial sectional view showing an iron core portion of an ignition coil for an internal combustion engine (third embodiment).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ignition coil (ignition coil for internal combustion engine) 2 Primary coil 3 Secondary coil 4 First core 5 Second core 6 Permanent magnet 13 Plug tube 51 Cylindrical core (cylindrical part)

Claims (1)

[Claims] 1. A first core, which is disposed in a cylindrical plug tube made of a conductive material of an internal combustion engine, is directly connected to an ignition plug, and is a laminated body formed by laminating a plurality of flat magnetic materials into a round bar shape. A primary coil and a secondary coil disposed on the outer periphery of the first core; and a cylindrical portion for housing the primary coil, the secondary coil, and the first core therein, In a method for manufacturing an ignition coil including a first core and a second core made of a magnetic material forming a magnetic path, the cylindrical portion of the second core is formed by bending a flat plate made of a magnetic material into a substantially cylindrical shape, A method for manufacturing an ignition coil for an internal combustion engine, comprising forming a cylindrical gap formed when both ends of the flat plate are butted together.