JP4590699B2 - Ignition coil device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ignition coil device for an internal combustion engine (hereinafter referred to as an “internal combustion engine”), and more particularly to a stick-like ignition coil device that is directly mounted in a plug hole.
[0002]
[Prior art]
The ignition coil device generates a spark by applying a high voltage to the spark plug. When sparks are generated and high-frequency noise is generated, the high-frequency noise reaches the winding of the secondary coil and is radiated to the outside as radio wave noise from the secondary coil. When various electronic devices such as radio and television receive this radio noise, the reception state deteriorates.
In the ignition coil device disclosed in British Patent Application No. 2328324, a ferromagnetic member is disposed in a coil spring that electrically connects a secondary coil and a spark plug, and a filter that removes noise by the coil spring and the ferromagnetic member. Is configured.
[0003]
A filter composed of a coil spring and a ferromagnetic member has frequency characteristics. That is, there are a frequency at which the peak value can be reduced and a frequency at which the peak value can hardly be reduced. For example, when the vehicle type or engine type changes, the frequency distribution of noise may change. In such a case, it is necessary to adjust the frequency characteristics of the filter. The effective frequency at which the filter composed of coil spring and ferromagnetic member can reduce the peak value is
It can be adjusted by changing the length of the ferromagnetic member, the cross-sectional area of the ferromagnetic member, the magnetic permeability of the ferromagnetic member, the number of turns of the coil spring around the ferromagnetic member, and the winding pitch of the coil spring around the ferromagnetic member.
[0004]
[Problems to be solved by the invention]
However, since the coil spring that is electrically connected to the ignition coil by elastic force is limited in elastic force and axial length, it is difficult to change the number of turns and the winding pitch. Furthermore, since it is necessary to prepare different coil springs for each number of turns or winding pitch, the types of parts increase. In addition, in the case of a stick-like ignition coil device to be inserted into the plug hole, if the number of turns of the coil spring is increased or the winding pitch is increased, the length of the coil spring becomes longer and the ignition coil device protrudes from the plug hole. There is.
[0005]
An object of the present invention is to provide an ignition coil device that easily adjusts the frequency characteristics of noise that can reduce the peak value by changing the winding method of the dummy coil wound to prevent dielectric breakdown from the low voltage side. Is to provide.
Another object of the present invention is to provide an ignition coil device that prevents dielectric breakdown between a high voltage side and a low voltage side and easily adjusts a noise peak value reduction rate by changing a resistance value. There is.
[0006]
[Means for Solving the Problems]
[0008]
Ignition coil according to claim 1 of the present invention includes a rod-like core, the primary spool is disposed so as to surround the outer periphery of the core and the secondary spool and a primary coil wound on the primary spool, And a secondary coil wound around the secondary spool, a terminal member disposed away from the high voltage side of the secondary coil, and a high voltage side of the secondary coil and the terminal member. And a resistor that electrically connects the high voltage side of the secondary coil and the terminal member, and a rubber material that covers the resistor. According to the present invention, the noise peak value can be reduced by the resistor that electrically connects the high voltage side of the secondary coil and the terminal member. Further, the resistor also serves as a connecting member for electrically connecting the high voltage side of the secondary coil and the terminal member, and the resistor is provided in the secondary spool by utilizing the space in the terminal member side end of the secondary spool. Is accommodated, the extension of the axial length of the ignition coil device can be reduced as much as possible.
[0009]
According to the ignition coil device of the second aspect of the present invention, the resistance value of the resistor is changed between 3 kΩ and 50 kΩ.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a plurality of examples showing embodiments of the present invention will be described with reference to the drawings.
(First Reference Example )
An ignition coil device according to a first reference example of the present invention is shown in FIG. The ignition coil device 10 is accommodated in a plug hole formed for each cylinder in an upper portion of an engine block (not shown), and is electrically connected to an ignition plug (not shown) as an ignition device on the lower side of FIG.
[0011]
The ignition coil device 10 includes a cylindrical coil case 11 and a high-pressure tower 12 each made of a resin material. In the coil case 11 and the high-pressure tower 12, a central core 15 as a core, a secondary spool 20, a secondary The coil 21, the primary spool 23, the primary coil 24, the outer peripheral core 25, the ferromagnetic member 40, and the like are accommodated. The epoxy resin 26 filled in the coil case 11 and the high-voltage tower 12 permeates between the members in the ignition coil device 10, and ensures electrical insulation between the members as a resin insulating material.
The cylindrical central core 15 is assembled by laminating thin silicon steel plates in the radial direction so that the cross section is substantially circular. A rubber material 18 covers the outer periphery of the center core 15 as an insulating material.
[0012]
The secondary spool 20 is disposed outside the rubber material 18 and is molded from a resin material. The secondary coil 21 is wound around the outer periphery of the secondary spool 20, and a dummy coil 22 is continuously wound around the secondary coil 21 on the high voltage side of the secondary coil 21 as a single winding. ing. The dummy coil 22 electrically connects the high voltage side of the secondary coil 21 and the U-order terminal 50. The wire at the high voltage end of the dummy coil 22 is electrically connected to the U-order terminal 50 attached to the secondary spool 20 by fusing or soldering. By electrically connecting the secondary coil 21 and the U-order terminal 50 with the dummy coil 22 instead of a single wire, the surface area of the electrical connection portion between the secondary coil 21 and the U-order terminal 50 is increased, and the electrical connection is made. Avoiding electric field concentration on the part.
[0013]
The primary spool 23 is disposed outside the secondary coil 21 and is formed of a resin material. The primary coil 24 is wound around the outer periphery of the primary spool 23.
The outer peripheral core 25 is mounted on the outer side of the primary coil 24. The outer peripheral core 25 winds a thin silicon steel plate in a cylindrical shape and does not connect the winding start end and the winding end end, so that a gap is formed in the axial direction.
[0014]
The igniter 27 is disposed in the upper part in the coil case 11 and switches a primary current supplied to the primary coil 24. The control signal input connector 30 is provided on the coil case 11 so as to protrude from the plug hole. A plurality of terminals 31 are insert-molded in the connector 30. Each terminal 31 is electrically connected to the igniter 27, the ground side of the secondary coil 21, and the ground side of the primary coil 24 by lead wires.
[0015]
The ferromagnetic member 40 is formed in a cylindrical shape from ferrite or the like, and is disposed inside the secondary spool 20 around which the dummy coil 22 is wound. It is desirable that the corners of the ferromagnetic member 40 have a shape such as R chamfering, C chamfering, stepping, or the like so that a potential difference from the wire rods at both ends of the dummy coil 22 that is a high voltage portion does not increase.
[0016]
The high voltage terminal 51 is press-fitted into the high voltage tower 12. The tip of the high voltage terminal 51 is inserted into the U-shaped terminal 50, and the high voltage terminal 51 is electrically connected to the high voltage side of the secondary coil 21 via the U secondary terminal 50. The U-order terminal 50 and the high-voltage terminal 51 constitute a terminal member. The portion of the high voltage terminal 51 extending to the secondary coil side has an opposing area facing the low voltage side to such an extent that dielectric breakdown from the low voltage side is prevented.
[0017]
The spring 52 is electrically connected to the high voltage terminal 51 and electrically connected to the spark plug when the ignition coil device 10 is inserted into the plug hole. A plug cap 19 made of rubber is attached to the open end of the high voltage tower 12 on the high voltage side, and an ignition plug is inserted into the plug cap 19.
When the primary current supplied to the primary coil 24 is switched by the igniter 27, a high voltage is generated in the secondary coil 21, and this high voltage is applied to the spark plug via the dummy coil 22, the U-order terminal 50, the high-voltage terminal 51, and the spring 52. Applied.
[0018]
When a high voltage is applied to the spark plug and a spark is generated at the spark plug, high-frequency noise is generated along with the spark. The dummy coil 22 and the ferromagnetic member 40 disposed in the dummy coil 22 constitute a noise filter, and reduce the peak value of high-frequency noise generated by the spark plug.
[0019]
The effective frequency of noise at which the filter composed of the dummy coil 22 and the ferromagnetic member 40 can reduce the peak value is
The length of the ferromagnetic member 40 The cross-sectional area of the ferromagnetic member 40 The permeability of the ferromagnetic member 40 The number of turns of the dummy coil 22 around the ferromagnetic member 40 The winding pitch of the dummy coil 22 around the ferromagnetic member 40 It can be adjusted by changing. In the first reference example , the effective frequency of noise that can reduce the peak value can be easily adjusted by changing the number of turns of the dummy coil 22.
Further, since the ferromagnetic member 40 is disposed in the secondary spool 20 inside the dummy coil 22 that prevents dielectric breakdown from the low voltage side, the shaft of the ignition coil device 10 is used to form a noise reduction filter. There is no need to increase the length.
[0020]
(Second reference example )
FIG. 3 shows a cross-sectional view including the ferromagnetic member of the ignition coil device according to the second reference example of the present invention. A plurality of ribs 61 are formed on the inner peripheral wall of the secondary spool 60, and the ribs 61 support the ferromagnetic member 62. Since a gap is formed between the secondary spool 60 and the ferromagnetic member 62, the epoxy resin 26 can pass around the ferromagnetic member 62.
[0021]
FIG. 4 shows a modification of the second reference example . By forming the notch 66 on the opposite side of the ferromagnetic member 65 in the radial direction, a gap is formed between the secondary spool 20 and the ferromagnetic member 65. Therefore, the epoxy resin 26 can pass around the ferromagnetic member 65.
[0022]
( Third reference example )
FIG. 5 shows the configuration around the ferromagnetic member of the ignition coil device according to the third reference example of the present invention. An insulating rubber spacer 71 is inserted between the ferromagnetic member 40 and the high voltage terminal 51. Concave portions 72 extending in the axial direction are formed on both radial sides of the spacer 71. The epoxy resin 26 passes between the recess 72 and the secondary spool 70.
[0023]
The spacer 71 prevents the ferromagnetic member 40 and the high-voltage terminal 51 from coming into contact with each other, and prevents the potential difference between the ferromagnetic member 40 and the secondary spool 20 from increasing. Thereby, the dielectric breakdown of the secondary spool 70 can be prevented. The spacer may be formed using an insulating resin instead of the insulating rubber.
[0024]
( 4th reference example)
An ignition coil device according to a fourth reference example of the present invention is shown in FIG. The same components as those in the first reference example are denoted by the same reference numerals. The ferromagnetic member 81 is in contact with the end face of the central core 15 on the high voltage terminal 51 side and is covered with the rubber material 18 together with the central core 15. The dummy coil 22 is wound around the secondary spool 80 outside the ferromagnetic member 81. Since the ferromagnetic member 81 is disposed in contact with the central core 15, the axial length of the ignition coil device is shortened.
[0025]
In the first to fourth reference examples described above, a ferromagnetic member is arranged inside the dummy coil 22 to constitute a noise filter. By changing the number of turns of the dummy coil, the effective frequency of noise that reduces the peak value can be easily adjusted. Therefore, it is possible to cope with changes in the frequency distribution of noise generated with sparks in the spark plug depending on the vehicle type, engine type, etc., by simply changing the number of turns of the dummy coil without replacing parts or adding another part.
[0026]
( 5th reference example)
An ignition coil device according to a fifth reference example of the present invention is shown in FIG. The same components as those in the first reference example are denoted by the same reference numerals. The resistor 90 is accommodated in the end of the secondary spool 85 on the high voltage terminal 51 side. The resistor 90 which is a high voltage part has an opposing area facing the low voltage side to such an extent that dielectric breakdown with the low voltage side is prevented. Terminals 91 and 92 are attached to both sides of the resistor 90 in the axial direction. Terminal 91 is connected to the dummy coil 22 and electrical terminal 92 is electrically connected to 5 1 and the high-voltage terminal.
[0027]
When the resistance value of the resistor 90 increases, the high voltage generated in the secondary coil 21 decreases. When the resistance value of the resistor 90 decreases, the noise peak value reduction rate decreases. In the fifth reference example, by setting the resistance value of the resistor 90 between 3 kΩ and 50 kΩ, the noise peak value is reduced, and the high voltage drop generated in the secondary coil 21 is reduced. By changing the resistance value of the resistor 90 between 3 kΩ and 50 kΩ, the noise peak value reduction rate changes.
[0028]
In the fifth reference example, the resistor 90 also serves as a connecting member that connects the dummy coil 22 as a connecting portion and the high-voltage terminal 51 as a terminal member, and the space in the end portion on the high-voltage terminal 51 side of the secondary spool 20. Since the resistor 90 is accommodated in the secondary spool 20 by using this, it is possible to reduce the extension of the axial length of the ignition coil device as much as possible.
[0029]
The dummy coil 22 may be eliminated and the secondary coil 21 may be wound up to the dummy coil portion. Since the portion extending to the secondary coil side of the high voltage terminal 51 has an opposing area facing the low voltage side to such an extent that dielectric breakdown with the low voltage side is prevented, the high voltage terminal 51 includes a connection portion, a terminal member, It will also serve as. Since the terminal member 51 also serves as a connection portion, the number of parts can be prevented from increasing, and the number of assembling steps for the ignition coil device can be reduced. In this case, the resistor 90 electrically connects the high voltage side of the secondary coil 21 and the terminal member 51 as a connection portion.
[0030]
(First Embodiment)
FIG. 8 shows the configuration around the resistor of the ignition coil device according to the first embodiment of the present invention. The same components as those in the fifth reference example are denoted by the same reference numerals. An insulating rubber material 95 covers the resistor 90. Since the difference in expansion coefficient between the resistor 90 and the epoxy resin 26 is large, if the resistor 90 and the epoxy resin 26 are in direct contact, the epoxy resin 26 in contact with the resistor 90 is cracked due to a temperature change. May occur. In the first embodiment, since the insulating rubber material 95, which is an elastic material, covers the resistor 90, the stress acting on the epoxy resin 26 is relaxed, and it is possible to prevent the epoxy resin 26 from cracking. Instead of the insulating rubber material 95, an insulating resin material may be used.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing a high voltage side of an ignition coil device according to a first reference example of the present invention.
FIG. 2 is a longitudinal sectional view showing an ignition coil device according to a first reference example.
FIG. 3 is a transverse sectional view showing the periphery of a ferromagnetic member according to a second reference example of the present invention.
FIG. 4 is a cross-sectional view showing a modification of the second reference example.
FIG. 5A is a longitudinal sectional view showing the periphery of a ferromagnetic member according to a third reference example of the present invention, and FIG. 5B is a sectional view taken along line BB of FIG.
FIG. 6 is a longitudinal sectional view showing a high voltage side of an ignition coil device according to a fourth reference example of the present invention.
FIG. 7 is a longitudinal sectional view showing a high voltage side of an ignition coil device according to a fifth reference example of the present invention.
FIG. 8 is a longitudinal sectional view showing the periphery of the resistor according to the first embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Ignition coil apparatus 11 Coil case 12 High voltage tower 15 Central core (core)
20, 60, 70, 80, 85 Secondary spool 21 Secondary coil 22 Dummy coil (connection part)
23 Primary spool 24 Primary coil 40, 62, 65, 81 Ferromagnetic member 50 U-shaped terminal (terminal member)
51 High-voltage terminal (connection part, terminal member)
90 resistors

Claims (2)

A rod-shaped core,
A primary spool and a secondary spool disposed so as to surround the outer periphery of the core;
A primary coil wound around the primary spool, and a secondary coil wound around the secondary spool;
A terminal member disposed away from the high voltage side of the secondary coil;
A resistor disposed between the high voltage side of the secondary coil and the terminal member, and electrically connecting the high voltage side of the secondary coil and the terminal member ;
A rubber member covering the resistor;
An ignition coil device comprising: The ignition coil device according to claim 1, wherein the resistance value of the resistor is changed between 3 kΩ and 50 kΩ .

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