JPH0636305Y2 - Ignition coil for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to an ignition coil for igniting a normal internal combustion engine mounted on a motor vehicle, and more particularly to an improvement in a method of grounding an iron core.

[Prior Art] As shown in FIG. 2 (A), an existing resin mold type ignition coil 10 for applying a high voltage to an ignition plug of an internal combustion engine.
Is usually for connecting the iron core 11, the primary and secondary coil parts 12 wound around the iron core 11, and the high voltage terminals 13 and 13 for extracting the secondary coil output, and the primary current power supply. The low-voltage terminal (not visible in the figure) is integrally molded with a suitable resin, but the iron core terminal 14 such as the conductive pattern electrically connected to the built-in iron core is also provided. Or, at the time of mounting, this conductive pattern 14 is used by connecting and wiring to an appropriate ground potential portion E of the vehicle with an appropriate external lead wire 15.

This will be explained with an equivalent circuit as shown in FIG. 2 (B). Of course, the iron core 21 is internally provided with the iron core 21 of the ignition coil, and the iron core 21 is wound with the primary coil 22 and the secondary coil 23. Has been.

One end of the primary coil 22 is normally connected to a hot side terminal of a battery 24 mounted on a vehicle, and the other end is connected to a switching means 25 such as a transistor that selectively cuts off the primary current.

Both ends 13, 13 of the secondary coil 23 or one end thereof are connected to a spark plug (not shown).

The operation itself of the ignition coil in such a basic circuit configuration has been known for a long time, and since the present invention is not related to the driving principle of this ignition coil, a detailed description thereof will be omitted. On the contrary, even if the type that generates a high voltage on the secondary coil side by a method other than the current cutoff mechanism, the iron core 21 is connected to the ground E by the external lead wire 15 as shown in the figure. The following description can be applied as it is, and can be an object of improvement of the present invention.

By the way, as shown in the figure, the iron core 21 is electrically connected to the ground potential E through the external lead wire 15 by flowing the voltage induced in the iron core 21 to the external ground, so that the radio installed in the vehicle, The purpose of this is to prevent noise from being generated in various electronic devices, which is a conventional common sense fact in the mounting technology of this kind of ignition coil.

[Problems to be Solved by the Invention] As described above, the electric potential of the iron core of the ignition coil to be grounded by the external lead wire is of course no problem as far as electrical consideration is concerned. Is preferred.

However, for that purpose, the external lead wire 15 is separately prepared and placed, and this is exposed somewhere in the product completed as a resin-molded coil and the core terminal portion 14 and somewhere in the vehicle structure part as well. Wiring between the ground terminal E provided at an appropriate location is not always easy,
In many cases, it was rather troublesome.

If it is not necessary to separately prepare such an external lead wire, and, of course, there is no need for wiring for grounding the iron core, the overall workability of mounting the ignition coil is significantly improved, The efficiency is increased and the product cost is reduced.

The present invention was made with a clear sense of purpose in this respect.Electrically, as in the past, it is possible to take measures against the induced voltage generated in the iron core, and the induced voltage causes noise to various electronic devices mounted on the vehicle. The present invention aims to provide a new structure of the ignition coil which does not require external wiring for the iron core.

[Means for Solving the Problems] In order to achieve the above object, the present invention is for an internal combustion engine in which an iron core of an ignition coil is electrically connected to a primary coil terminal on a side connected to a battery, directly or through a resistor. Providing an ignition coil.

[Operation] In the present invention, the iron core is connected to the primary coil terminal connected to the hot side of the battery, not to the ground potential as in the conventional case. However, considering that the induced voltage is an AC component, it eventually becomes equivalent to the iron core potential being grounded via the battery, and the action itself is the same as in the conventional case.

In other words, as an electrical problem, the structure that can sufficiently reduce the risk of the induced voltage becoming a noise generation source as in the conventional case.

However, electrically like this,
Although the structure is not damaged, the structure of the present invention can eliminate the wiring procedure via the external lead wire, unlike the conventional example, considering the mounting problem.

That is, the work of placing the iron core by connecting it directly or through a resistor to the hot side terminal of the primary coil of the ignition coil can be performed in advance at an appropriate stage of the manufacturing process for completing the ignition coil as a product, and it is completed as a product. When this is done, it can be resin-molded together with other structural elements.

Therefore, at the time of mounting, it is sufficient to perform a predetermined wiring work only for the primary terminal and the secondary terminal of the ignition coil device, and the auxiliary wiring work for the iron core, which has been conventionally required, is unnecessary.

[Embodiment] FIG. 1 shows an embodiment of an ignition coil 10 constructed according to the present invention. FIG. 2A is a rear view, and the front surface side is the same as the conventional one shown in FIG. 2A except that the conductor pattern connected to the iron core or the iron core terminal portion 14 is not necessary. good. Therefore, the same reference numerals as those used with reference to FIG. 2 are used for the components which do not need to be modified according to the present invention, and the description thereof is based on that of the conventional example described above. Some may omit the description.

As shown in FIG. 1 (A), a resin-molded ignition coil 10 of this type is provided with terminals 32 and 33 at both ends of a primary coil 22 incorporated in a coil portion 12. Among them, as shown in FIG. 1 (B), a resistor 31 having one end connected to a terminal 32 connected to the hot side of the vehicle-mounted battery 24 in the mounted state is provided.
The other end of 31 is electrically connected to the iron core 21 built in the iron core portion 12.

Even in this case, the AC induction voltage component that can be induced in the iron core 21 under the use condition is such that the current component causes the resistance 31 to pass through the hot side terminal 32 of the primary coil and the power source, as shown by the arrow I _i. Is absorbed (grounded via the battery 24), it is possible to electrically expect the same effect as in the case where the iron core 21 is directly grounded in the related art. It is possible to suppress the risk of becoming noise to various electronic devices mounted.

Nevertheless, as can be understood from the place shown in FIG. 1 (A), the resistor 31 has a core portion 11, a coil portion 12, and other terminal portions 32, 33; Each of the constituent elements of the ignition coil 10, including the root part, can be integrally resin-molded and can be placed in advance as an internal part of the ignition coil 10 at a stage before being completed as a product.

In other words, the resistor 31 newly added by the present invention also
By the resin molding in the final stage after finishing the predetermined wiring, the ignition coil 10 can be housed inside the device structure as a whole.

Therefore, when mounting the ignition coil 10 on a vehicle, low-voltage and high-voltage terminals 32, 33;
Only with respect to 13, it suffices to perform a predetermined wiring work similar to that described in the conventional example, and the wiring work for the iron core 21 is completely unnecessary.

Further, in the case of the embodiment of FIG. 1, the iron core 21 is connected to the hot side terminal 32 of the primary coil 22 via the resistor 31, but this is simply connected directly by the lead wire. Even so, the electrical effect is the same. However, considering even the case where some leakage current other than the induced voltage flows, it is better to place a connection to the iron core 21 via the resistor 31 because the resistor 31 can consume the leakage current, The degree of security is high.

Of course, the modified portion of the present invention is the ignition coil which is the object of improvement in the illustrated embodiment, both in terms of form and equivalent circuit.
The present invention can also be applied to a device different from 10, and in other words, if it has conventionally adopted a separate external wiring lead for iron core grounding, it is equally applicable to the improvement of the present invention.

[Effect] In the present invention, since the iron core is connected to the hot side terminal of the primary coil in order to reduce the induced voltage induced in the iron core of the ignition coil, the predetermined wiring for the primary coil is performed. Then, the iron core is automatically grounded with respect to the induced voltage.

Therefore, as in the conventional case, a grounding lead wire is prepared exclusively for the iron core, one end of which is exposed to the iron core terminal part somewhere in the resin-molded ignition coil device, and the other end of which is somewhere in the vehicle. It is not necessary to connect the ground terminals provided to each, and the mounting work efficiency can be greatly improved.

Further, as in the conventional case, when the iron core is grounded with a dedicated external lead wire, there is a risk that grounding failure will occur if one operator makes a mistake.However, in the ignition coil of the present invention, the iron core is primary in the manufacturing stage. Since it is connected to the hot side terminal of the coil, if the connection between the primary coil and the battery is perfect, then it automatically ensures that the core ground is also complete. If you forget to connect the hot side terminal of the ignition coil to the battery, it will not operate as an ignition coil.Therefore, you will not continue to use the ignition coil without noticing it as before, and you will immediately notice a wiring mistake. You can

Naturally, the vehicle structure side does not require the iron core grounding terminal portion which has been conventionally required, so that the labor for designing and manufacturing therefor can be reduced, and in practice, this is also considerably useful.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a preferred embodiment of the present invention and an explanatory diagram of an example of an equivalent circuit in a use state, and FIG. 2 is an explanatory diagram of a conventional method of grounding an iron core of an ignition coil. In the figure, 10 is an ignition coil as a whole, 21 is an iron core, 22 is a primary coil, 24 is a battery mounted on a vehicle, 31 is a resistor, and 32 is a hot side terminal of the primary coil.

Claims (1)

[Scope of utility model registration request] 1. An ignition coil for an internal combustion engine, comprising an iron core, a primary coil and a secondary coil wound around the iron core, wherein the iron core is a battery mounted on a vehicle in both terminals of the primary coil. An ignition coil for an internal combustion engine, which is connected to a terminal connected to the hot side of the engine directly or through a resistor.