JPH06325955A - Ignition device for internal combustion engine, and ignition device mounting type distributor - Google Patents

Abstract

PURPOSE:To obtain an ignition device and a distributor mounted therewith which are usable in a high-temperature condition and are excellent in a durability, by forming its partition type secondary coil bobbin out of a thermosetting synthetic resin. CONSTITUTION:A primary coil 2 is wound around a primary coil bobbin 1 formed out of a thermoplastic synthetic resin, and a secondary coil 4 is wound around a partition type secondary bobbin 3 formed out of such a thermosetting synthetic resin as an epoxy resin. The ends of the secondary coil 4 are connected respectively with high-voltage terminals 8 provided in the inner part of a high-voltage tower 7, and therefrom, the high voltage induced on the secondary side is distributed to the ignition plugs of respective cylinders. As the epoxy resin, especially, the one whose glass transition temperature is not lower than 135 deg.C and whose linear expansion coefficient is 35X10<-6>/ deg.C at a temperature not higher than its glass transition temperature is used. Also, the power of an inorganic substance not less than 50 weight percentage is mixed with the epoxy resin. Further, the partition type secondary coil bobbin 3 is formed by an injection molding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal combustion engine ignition device, and more particularly to an internal combustion engine ignition device and a distributor which are suitable for use in a high temperature state.

[0002]

2. Description of the Related Art As a conventional device, for example, Jitsuko Sho 59-
As described in Japanese Patent No. 34105, there is one in which a split type secondary coil bobbin of an ignition coil is formed of a thermoplastic synthetic resin.

[0003]

However, particularly in the case of the distributor built-in type and / or the engine direct mounting type simultaneous ignition ignition coil, the internal temperature of the ignition coil becomes very high because the engine heat is directly received in addition to the self-heating. Therefore, the secondary coil bobbin formed of the above-mentioned conventional thermoplastic synthetic resin has a problem that dielectric breakdown occurs between the secondary coil layers and between the secondary coil high-voltage side upper ground in a high temperature region exceeding 150 ° C. .

An object of the present invention is to provide an ignition device for an internal combustion engine and an ignition device-mounted distributor which can be used under high temperature conditions and have excellent durability.

[0005]

Means for Solving the Problems The above object is to electrically couple a primary coil with the primary coil through an iron core.
In an ignition device for an internal combustion engine, comprising: a secondary coil continuously wound on a split secondary coil bobbin having a plurality of winding grooves formed therein, wherein the split secondary coil bobbin is made of a thermosetting synthetic resin. It is achieved by forming.

Further, an ignition device for an internal combustion engine which achieves the above object comprises an ignition coil having a secondary coil whose coil bobbin is formed of thermosetting synthetic resin, and two high voltage terminals connected to the secondary coil. have.

Further, an ignition device-mounted type distributor that achieves the above object is a housing, a high-voltage tower portion that is provided in the housing and supplies a high voltage to an ignition plug, and is attached to the housing and is electrically connected to the high-voltage tower portion. In the ignition device mounting type distributor including the ignition coil that is electrically connected, the secondary coil bobbin of the ignition coil is formed of a thermosetting synthetic resin.

[0008]

Since the secondary coil bobbin is made of thermosetting synthetic resin, the insulating performance of the secondary coil bobbin in the high temperature region is improved.

[0009]

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

FIG. 1 is a sectional view showing the structure of an embodiment of the present invention. This ignition coil is a simultaneous ignition type ignition coil equipped with two high voltage towers 7 so that one coil can supply a high voltage to two cylinders. A primary coil 2 is wound around a primary coil bobbin 1 formed of a thermoplastic synthetic resin, and a secondary coil 4 is wound around a split type secondary coil bobbin 3 formed of a thermosetting synthetic resin such as an epoxy resin. The ends of the secondary coils 4 are connected to the high-voltage terminals 8 inside the high-voltage tower 7, respectively, and the high voltage induced on the secondary side is distributed to the ignition plug of each cylinder. A wound primary coil bobbin 1 and a split type secondary coil bobbin 3
Is fitted and fixed to the coil case 6. An insulating casting resin 5 made of a thermosetting synthetic resin such as an epoxy resin is injected and impregnated between the coil case 6 and the split type secondary coil bobbin 3 and the primary coil bobbin 1 and then heat-cured.

Next, the advantages of using a thermosetting synthetic resin for the split type secondary coil bobbin 3 will be described.
The problem in the case of using the thermoplastic synthetic resin will be described with reference to FIG. A thermoplastic synthetic resin has a linear expansion coefficient remarkably large when the temperature is in a temperature range exceeding the glass transition temperature. Therefore, peeling occurs at the interface between the split type secondary coil bobbin 3 formed of a thermoplastic synthetic resin and the insulating casting resin c, and the ignition coil is used in a state in which a high electric field is applied, so that partial discharge occurs at the peeling portion. Occurs, and eventually dielectric breakdown e occurs and the function as an ignition coil is impaired. On the other hand, even if the thermosetting synthetic resin exceeds the glass transition point, the change in the linear expansion coefficient is smaller than that of the thermoplastic synthetic resin, so that peeling occurs at the interface between the split secondary coil bobbin 3 and the insulating casting resin 5. Hateful.
Since the peeling that triggers the dielectric breakdown does not easily occur, the ignition coil can be used at a higher temperature. Among thermosetting synthetic resins, epoxy resin is particularly excellent in its characteristics, and epoxy resin is also used as the insulating casting resin 5, so that peeling hardly occurs at the interface, that is, in order to make the linear expansion coefficient the same, An epoxy resin is used for the split type secondary coil bobbin 3. Among epoxy resins, the glass transition temperature is especially 135.
The coefficient of linear expansion at 35 ° C or above and below the glass transition temperature is 35
Those of × 10 ^-6 / ° C are less likely to cause peeling at the interface, improve high temperature durability and have good moldability. However, if the glass transition point is too high, the mold temperature at the time of molding becomes high and the workability deteriorates. Therefore, it is necessary to select a glass transition temperature of 135 ° C to 170 ° C. In addition, the thermosetting resin is mixed with a filler such as an inorganic powder in order to improve the impact resistance in view of its characteristics, but the characteristics change depending on the ratio as shown in FIG. If the weight ratio of the inorganic powder is less than 50%, the impact resistance is not satisfied. When it is 71% or more, the clay at the time of molding becomes high, and precision injection molding becomes impossible. Therefore, the weight division of the inorganic powder of the epoxy resin used for the split secondary coil bobbin 3 is ideally 50 to 70%. Moreover, by using the epoxy resin having the above-mentioned characteristics for the split type secondary coil bobbin 3, injection molding becomes possible and the productivity is improved.

Next, an embodiment of using the ignition coil having the split type secondary coil bobbin 3 will be described with reference to FIGS.

FIG. 4 shows that the simultaneous ignition type ignition coil 100 is directly attached to the engine 101 via the bracket 103. As shown in this figure, the simultaneous ignition type ignition coil 100 is attached to the upper part of the engine 101, or is attached to the side of the engine 101 (not shown) and is supplied to the ignition plug by a high voltage connection line called a high tension cable 102. To do. When directly attached to the engine in this way, the ignition coil 10
In addition to the internal heat generation, 0 directly receives heat from the engine 101. Furthermore, recent engine rooms tend to be compact or dense due to the installation of various control devices, and heat dissipation cannot be expected so much. Therefore, the engine 10
If it is attached directly to No. 1, it will be a very severe thermal condition. Under such conditions, it is essential to use the ignition coil having the split secondary coil bobbin 3 made of thermosetting synthetic resin.

FIG. 5 shows an embodiment of the present invention in which the ignition coil 202 is built in the housing 201 of the distributor 200.

The ignition coil 202 is built in the distributor 201, and the high voltage tower 203 of the ignition coil 202 is electrically connected to the power distribution rotor 204 and is installed in the housing 201 of the distributor 200.
Power is distributed to 05. As shown in FIG. 5, the distributor 200 is a component that is directly attached to the engine 300. Therefore, heat dissipation can hardly be expected for the ignition coil built into the housing 201, and in this case also, the condition is thermally very severe. Therefore, the ignition coil 20 including the split type secondary coil bobbin using the thermosetting synthetic resin is provided.
By using 2, it is possible to improve heat resistance.

Next, the effect of the embodiment of the present invention will be described with reference to FIG.
Will be explained. The internal temperature of the ignition coil is 150 ° C and 1
It is a comparison of the endurance time when the ignition coil is operated in a high temperature atmosphere such as 70 ° C. It can be seen that the conventional product has a durability of about 20 to 200 hours at 170 ° C., whereas the product of the present invention has a durability of 1000 hours or more.

[0017]

According to the present invention, since the heat resistance of the ignition coil can be improved, the durability of the ignition coil can be improved. In particular, the insulation durability of the simultaneous ignition type ignition coil directly mounted on the engine and the ignition coil mounted in the housing of the distributor can be significantly improved.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of an ignition device of the present invention.

FIG. 2 is a diagram illustrating a problem of a conventional secondary coil bobbin.

FIG. 3 is a characteristic change diagram depending on the ratio of the filler contained in the thermosetting synthetic resin of the present invention.

FIG. 4 is a diagram showing a state in which the ignition device of the present invention is attached to an engine.

FIG. 5 is a diagram showing a distributor incorporating the ignition device of the present invention.

FIG. 6 is a diagram showing a state in which the distributor of FIG. 5 is attached to an engine.

FIG. 7 is a diagram for explaining the effect of the present invention.

[Explanation of symbols]

1 ... Primary coil bobbin, 2 ... Primary coil, 3 ... Split secondary coil bobbin, 4 ... Secondary coil, 5 ... Insulation casting resin,
6 ... Coil case, 7, 203 ... High voltage tower, 8 ... High voltage terminal, 101, 300 ... Engine, 100 ... Simultaneous ignition type ignition coil, 102 ... High tension cord, 103 ...
Bracket, 200 ... Distributor, 201 ... Housing, 202 ... Distributor built-in ignition coil.

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Claims (10)

[Claims] 1. A primary coil and a secondary coil electrically coupled to the primary coil via an iron core and continuously wound on a split type secondary coil bobbin having a plurality of winding grooves formed therein. In the ignition device for an internal combustion engine, the split secondary coil bobbin is formed of a thermosetting synthetic resin. 2. The ignition device for an internal combustion engine according to claim 1, wherein the thermosetting synthetic resin is an epoxy resin. 3. The ignition device for an internal combustion engine according to claim 2, wherein the epoxy resin contains 50% or more by weight of inorganic powder. 4. The epoxy resin according to claim 2, wherein the epoxy resin is a material having a glass transition temperature of 135.degree. C. or higher and a linear expansion coefficient of ^{35.times.10.sup.-6} / .degree. C. at the glass transition temperature or lower. Ignition device for internal combustion engine. 5. The ignition device for an internal combustion engine according to claim 1, wherein the split type secondary coil bobbin is formed by injection molding. 6. An ignition system for an internal combustion engine, wherein a coil bobbin has an ignition coil provided with a secondary coil formed of a thermosetting synthetic resin and two high voltage terminals connected to the secondary coil. apparatus. 7. The ignition device for an internal combustion engine according to claim 6, wherein the ignition coil is a simultaneous ignition type. 8. An ignition device for an internal combustion engine, wherein the ignition device according to any one of claims 1 to 6 is attached to an engine. 9. A housing, a high-voltage tower portion provided in the housing for supplying a high voltage to an ignition plug, and an ignition coil attached to the housing and electrically connected to the high-voltage tower portion. An ignition device mounting type distributor, wherein the secondary coil bobbin of the ignition coil is formed of a thermosetting synthetic resin. 10. The ignition device mounting type distributor according to claim 9, wherein the ignition coil is incorporated in the housing.