JP2011035019A - Ignition coil for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the assembling of an ignition coil for an internal combustion engine and handling in exchanging components. <P>SOLUTION: An inward projection 13a is formed in the cylinder of a high voltage cylindrical part 13. The inward projection 13a supports the lower surface of a ceramic resistance 5 which is inserted from the upper surface of an insulating case 11 and enclosed by a stainless steel cap 6 by a size corresponding to the inner cylindrical diameter of the high voltage cylindrical part 13 by keeping electric connection. The upper surface of the ceramic resistance 5 is clogged by a high voltage terminal 4. Thus, the ignition coil for the internal combustion engine 1 is constituted. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an ignition coil for an internal combustion engine that supplies a high voltage to an ignition plug such as an automobile engine, for example, and can prevent a resistor used for reducing discharge noise from dropping without increasing the number of parts. The present invention relates to an ignition coil for an internal combustion engine that can be handled easily.

  For example, regarding an ignition coil for an internal combustion engine that supplies a high voltage to an ignition plug of an automobile engine or the like, there are known several configurations including the one proposed in Patent Document 1 below.

FIG. 3 is a schematic longitudinal sectional view illustrating an example of a conventional ignition coil for an internal combustion engine. In such an internal combustion engine ignition coil 10, an iron core-coil assembly 2 is provided on an insulating case 11 made of thermoplastic resin. An epoxy resin 24 is injected as an insulating resin that is accommodated and fixed while insulating between the components of the iron core-coil assembly 2, and a power source and control such as an external battery are connected to the connector portion 12 of the insulating case 11. A low voltage terminal 3 that is electrically connected to the unit or the like at one end is accommodated. A power switch 25 housed in the insulating case 11 together with the iron core-coil assembly 2 is electrically connected to the other end of the low voltage terminal 3. In addition, the high voltage cylinder portion 13 at the lower part of the insulating case 2 is attached and accommodated with a high voltage terminal 4 for supplying a high voltage to the plug of the engine.
The core-coil assembly 2 includes a primary coil 21, a secondary coil 22 wound concentrically with the primary coil 21, and a primary coil 21 and a secondary coil 22 that are inserted through the primary coil 21. And an iron core 23 that is magnetically coupled to each other. The secondary coil 22 and the high voltage terminal 4 are electrically connected via a high voltage connection pin 26.

  Here, in the ignition coil 10 for an internal combustion engine shown in FIG. 3, a high voltage is applied to an ignition plug (not shown) of the internal combustion engine to generate a spark, and at the same time, a high frequency noise is generated. A phenomenon occurs in which the coil reaches the winding and is radiated to the outside as radio noise from the secondary coil. Radio noise adversely affects various electronic devices such as radio and television. For this reason, it is necessary to provide the resistor 5A for reducing this, and in the conventional ignition coil 10 for an internal combustion engine, the resistor 5A is housed in the high-pressure cylinder portion 13 together with the high-voltage terminal 4. Specifically, after the high voltage terminal 4 is accommodated in the high voltage cylinder part 13, the resistor 5 </ b> A is inserted into the high voltage cylinder part 13 from the lower side of the insulating case 11 and accommodated.

  Patent Document 1 below relates to an ignition coil for an internal combustion engine that reduces a peak value of high-frequency noise generated with a spark in an ignition plug by a dummy coil and a ferromagnetic member arranged inside the dummy coil. An invention has been proposed.

Japanese Patent Laid-Open No. 2002-50528

However, as described above, the conventional internal combustion engine ignition coil 10 shown in FIG. 3 and the internal combustion engine ignition coil according to Patent Document 1 have the following problems.
In other words, after the high voltage terminal 4 is accommodated in the high pressure cylinder portion 13, the resistor 5 </ b> A is accommodated simply by being inserted into the high pressure cylinder portion 13 from the lower side of the insulating case 11. In the middle of assembly, the resistor 5A may fall off to the outside. This is because the resistor 5A has large dimensional tolerances including the diameter dimension and the length dimension, and cannot be fitted by press-fitting into the high-pressure cylinder 13 or the like. There was a problem of how to achieve accuracy.

  The present invention has been proposed in view of the above circumstances, and by reviewing a method for inserting a resistor into an ignition coil for an internal combustion engine and the like, by directly or indirectly providing the dimensional accuracy required for the resistor, The resistor can be prevented from falling out, and even various types of resistors can be attached, improving the ease of handling, and inadequate parts replacement at regular intervals It is an object of the present invention to provide an ignition coil for an internal combustion engine that can suppress the above.

  In order to achieve the above object, the present invention is made of a thermoplastic resin in which an upper surface is opened, a connector part that accommodates a low-voltage terminal is provided on one side, and a high-pressure cylinder part that accommodates a high-voltage terminal is provided on a lower part. In the insulation case, a primary coil, a secondary coil, and an iron core that magnetically couples the secondary coil and the primary coil are housed, and insulation resin is injected to maintain insulation between the housed components. In the internal combustion engine ignition coil constructed by inserting the high-voltage terminal and a resistor for reducing discharge noise into the cylinder of the high-pressure cylinder part, the lower surface of the resistor is disposed inside the cylinder of the high-pressure cylinder part. A supporting inward projecting portion is provided, and an upper surface of the resistor is covered with the high-voltage terminal.

  In particular, it is preferable that the resistor is supported by the inwardly protruding portion through a cap having a size corresponding to the cylinder inner diameter of the high-pressure cylinder portion.

  In the internal combustion engine ignition coil according to the present invention, since the inward projecting portion that supports the lower surface of the resistor is provided inside the cylinder of the high-pressure cylinder, the lower surface of the resistor is kept inside even during assembly. Since it is supported by the direction protrusion, even if the resistor has a large dimensional tolerance, it can be prevented from falling out. Furthermore, since the upper surface of the resistor is covered with the high voltage terminal, the insulating resin injected into the insulating case does not leak into the cylinder of the high pressure cylinder part, and there is a space inside the cylinder of the high pressure cylinder part. It is surely formed and the function of reducing the discharge noise of the resistor is not adversely affected, and this function can be exhibited to the maximum. In addition, in the present invention, for example, when replacing a part containing a conductor for connecting the resistor and the spark plug, the resistor does not fall out, so that the handling is improved. In addition, it is possible to suppress the trouble of replacing parts.

  Further, since the resistor is supported by the inward projecting portion via a cap having a size corresponding to the cylinder inner diameter of the high pressure cylinder portion, the shape of the high pressure cylinder portion of the internal combustion engine ignition coil is not changed. Even if the resistors have various sizes, the above-described effects can be obtained due to the presence of the cap. Further, the presence of the cap can indirectly provide the resistor with mechanical strength, corrosion resistance, and wear resistance. That is, according to the present invention, even when various types of resistors are attached, the resistors can be prevented from falling outside, and the resistors are provided with various advantageous performances, and the ease of handling is improved. It is possible to provide an ignition coil for an internal combustion engine.

It is a schematic longitudinal cross-sectional view of the ignition coil for internal combustion engines which concerns on this invention. It is a principal part enlarged view in FIG. It is a schematic longitudinal cross-sectional view of the conventional ignition coil for internal combustion engines.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same or equivalent part as the ignition coil for internal combustion engines shown in FIG. 3, and description is abbreviate | omitted.

  As shown in FIG. 1, the ignition coil 1 for an internal combustion engine according to the present invention has an open upper surface, a connector portion 12 that houses a low-voltage terminal 3 on one side, and a high-pressure cylinder portion that houses a high-voltage terminal 4 on the lower side. Insulating case 11 made of thermoplastic resin, each of which is provided with an iron core-coil assembly 2, and epoxy resin 24 as an insulating resin is injected to maintain insulation between the accommodating parts, and high pressure For example, a ceramic resistor 5 as a resistor for reducing discharge noise is inserted from the upper surface of the insulating case 11 into the cylinder of the cylinder portion 13.

  Further, as shown in FIG. 2, an inward projection 13 a as an inward projection that supports the lower surface of the ceramic resistor 5 inserted from the upper surface of the insulating case 11 is provided inside the cylinder of the high-pressure cylinder portion 13. Yes. Further, the ceramic resistor 5 is supported by the inward protrusion 13 a via a cap 6 made of, for example, stainless steel having a size corresponding to the cylinder inner diameter of the high-pressure cylinder portion 13. That is, the ceramic resistor 5 is surrounded by the stainless steel cap 6 while maintaining electrical connection inside the cylinder of the high-pressure cylinder 13, and is supported by the inward projection 13 a via the cap 6. It is. Note that the ignition coil 1 for an internal combustion engine according to the present invention is configured such that when the ceramic resistor 5 is inserted from the upper surface of the insulating case 11, the upper surface of the high-pressure cylinder portion 13 closes the upper surface.

Here, the inward projection 13 a provided inside the cylinder of the high-pressure cylinder 13 is a high-pressure cylinder that can be supported via the cap 6 on the lower surface side of the ceramic resistor 5 surrounded by the cap 6. What is necessary is just to make it protrude inward from the cylinder inner wall of the part 13. FIG. In addition, the inward projection 13a may be provided with two places every 180 degrees and three places every 120 degrees to support the ceramic resistor 5 surrounded by the cap 6. Moreover, even if the inward protrusion 13a is an inward annular protrusion which protruded annularly from the cylinder inner wall of the high pressure cylinder part 13, for example, it becomes a preferable form.
Further, the cap 6 surrounding the ceramic resistor 5 is a small resistor that may drop between the inward projections 13a even if the inward projection 13a is provided inside the cylinder of the high-pressure cylinder portion 13. This is necessary only when inserting the metal rod, i.e., used to reduce the tolerance between the outer dimension of the ceramic resistor 5 and the outer dimension inside the cylinder of the high-pressure cylinder 13. It has a size corresponding to the inner diameter.
In the present embodiment, the ceramic resistor 5 is exemplified as the resistor. However, for example, a resistor called a winding resistor formed by winding the periphery of the glass with a wire may be used. It is included in the present invention. In addition, the resistor is not particularly limited as long as it is a resistor that can be accommodated inside the cylinder of the high-pressure cylinder, and can reduce discharge noise.

  Hereinafter, the assembly of the ignition coil 1 for an internal combustion engine in the present embodiment will be briefly described.

  First, an insulating case 11 made of a thermoplastic resin is prepared in which the upper surface is opened, the connector portion 12 that houses the low-voltage terminal 3 on one side, and the high-pressure cylinder portion 13 that houses the high-voltage terminal 4 on the lower side. To do. Further, the connector portion 12 of the insulating case 11 accommodates a low-voltage terminal 3 that is electrically connected to a power source such as an external battery or a control unit at one end, and the high-pressure cylinder portion 13 below the insulating case 2 is connected to the engine. The ceramic resistor 5 is inserted from the upper surface together with the high voltage terminal 4 for supplying a high voltage to the plug. The ceramic resistor 5 is surrounded by a stainless cap 6 while maintaining electrical connection.

  At this time, first, the ceramic resistor 5 surrounded by the cap 6 is inserted into the high-voltage cylinder portion 13 from the upper surface of the insulating case 11, and then the high-voltage terminal 4 is closed with the upper surface of the ceramic resistor 5. 13 to accommodate. As a result, an inward projection 13a is provided inside the cylinder of the high-pressure cylinder portion 13, and the ceramic resistor 5 is supported on this, so that the ceramic resistor 5 falls off from the lower side of the high-pressure cylinder portion 13 to the outside. Disappears. In addition, even if the ceramic resistor 5 has various sizes, it is reliably secured to the high-pressure cylinder 13 by being surrounded by the cap 6 while maintaining electrical connection, and functions to reduce discharge noise. Will be able to.

Thereafter, the core-coil assembly 2 and the power switch 25 are accommodated in the insulating case 11, the other end of the low-voltage terminal 3 is electrically connected to the core-coil assembly 2 and the power switch 25, and the core-coil is further connected. The secondary coil 22 of the assembly 2 and the high-voltage terminal 4 are electrically connected via a high-voltage connection pin 26, and an epoxy resin 24 is injected and cured to maintain insulation between the housing components, thereby igniting the internal combustion engine. Assemble coil 1.
In the step of injecting and curing the epoxy resin 24, the high voltage terminal 4 is accommodated so as to cover the ceramic resistor 5 and cover the high voltage cylinder part 13. The epoxy resin 24 does not leak into the cylinder of the high-pressure cylinder 13, and the ceramic resistor 5 stays in the space inside the cylinder of the high-pressure cylinder 13, and the function of reducing discharge noise is the epoxy resin 24. It will not be disturbed.

  Further, in the ignition coil 1 for an internal combustion engine according to the present invention, for example, when the insulating cylinder containing the conductor connecting the ceramic resistor 5 and the spark plug is replaced, the inside of the cylinder of the high-pressure cylinder portion 13 is also changed. Due to the presence of the direction protrusion 13a, the ceramic resistor 5 does not fall out, the handling ease of replacement of the insulating cylinder is remarkably improved, and the trouble associated with the replacement of parts is remarkably suppressed.

  Therefore, in the ignition coil 1 for an internal combustion engine according to the present invention, first, an inward projection 13 a that supports the lower surface of the ceramic resistor 5 inserted from the upper surface of the insulating case 11 is provided inside the cylinder of the high-pressure cylinder portion 13. Therefore, even during assembly, the lower surface of the ceramic resistor 5 is supported by the inward projections 13a, so that the ceramic resistor 5 can be prevented from dropping from the lower side to the outside. Further, since the high voltage terminal 4 is accommodated so as to cover the upper surface of the inserted ceramic resistor 5 and cover the high voltage cylinder part 13, the epoxy resin 24 injected into the insulating case 11 is replaced with the high voltage cylinder part. 13 does not leak into the cylinder, and a space is surely formed inside the cylinder of the high-pressure cylinder 13 so that the function of reducing the discharge noise of the ceramic resistor 5 is not adversely affected. This function can be exhibited.

Further, the ceramic resistor 5 as a resistor is surrounded by a stainless steel cap 6 having a size corresponding to the cylinder inner diameter of the high-pressure cylinder portion 13 while maintaining an electrical connection. By being supported by 13a, the ignition coil 1 for an internal combustion engine according to the present invention can accommodate various ceramic resistors 5 having different outer dimensions, sizes, etc. in the high-pressure cylinder portion 13, By enclosing with the cap 6, the above-described effects can be obtained without changing the shape of the high-pressure cylinder portion 13. Further, since the cap 6 is made of stainless steel, the ceramic resistor 5 surrounded by the cap 6 can indirectly have performance such as mechanical strength, corrosion resistance, and wear resistance.
That is, according to the present invention, it is possible to prevent the ceramic resistor 5 (resistor) of various types from dropping from the lower side of the high-pressure cylinder portion 13 to the outside when assembling and replacing parts. Thus, it is possible to provide an ignition coil for an internal combustion engine that can significantly improve the ease of handling while providing various performances to the ceramic resistor 5 (resistor) surrounded by.

  As mentioned above, although one Embodiment of this invention was explained in full detail, this invention is not limited to the said one Embodiment. The present invention can be modified in various ways without departing from the scope of the claims.

Further, the present invention can change the shape of the ignition coil for the internal combustion engine without departing from the matters described in the claims. Needless to say, the materials used for the components of the ignition coil for an internal combustion engine of the present invention may be known or known materials.
For example, the cap that surrounds the resistor is used to reduce the outer dimensional tolerance between the resistor and the inside of the cylinder of the high-pressure cylinder, and the resistor is provided inwardly in the cylinder of the high-pressure cylinder. As long as it is a size that can be caught without passing between the protrusions, it is not necessarily an essential article in the present invention. In addition, as long as the shape corresponds to the inner diameter of the high-pressure cylinder, various design changes are possible, such as a shape that encloses the entire resistor and a shape that encloses only the upper and lower corners of the resistor. It is what. And if it is such a cap, it is possible to prevent the resistor from dropping out by supporting the lower surface of the resistor to the inward protruding portion inside the cylinder of the high-pressure cylinder part through itself. The effect which concerns on this invention can fully be exhibited.

DESCRIPTION OF SYMBOLS 1 ... Ignition coil for internal combustion engines 10 ... Conventional ignition coil for internal combustion engines 11 ... Insulating case 13 ... High pressure cylinder 13a / Inward projection (inward projection)
2 ... Iron core-coil assembly 21 ... Primary coil 22 ... Secondary coil 23 ... Iron core 24 ... Epoxy resin (insulating resin)
25..Power switch 26..High voltage connection pin 3. Low voltage terminal 4. High voltage terminal 5. Ceramic resistance (resistor)
5A ... Resistor (conventional)
6 ... Cap

Claims (2)

A primary coil and a secondary coil are provided in an insulating case made of a thermoplastic resin in which an upper surface is opened, a connector portion accommodating a low-voltage terminal on one side, and a high-pressure cylinder portion accommodating a high-voltage terminal on the lower side. And an iron core that magnetically couples the secondary coil and the primary coil, insulating resin is injected to maintain insulation between the housing components, and the high-voltage terminal is disposed inside the high-pressure cylinder portion. And an internal combustion engine ignition coil configured by inserting a resistor for reducing discharge noise,
In the cylinder of the high-pressure cylinder part, an inward projecting part that supports the lower surface of the resistor is provided, and the upper surface of the resistor is closed with the high-voltage terminal.
An ignition coil for an internal combustion engine. The resistor is supported by the inwardly protruding portion through a cap having a size corresponding to a cylinder inner diameter of the high-pressure cylinder part.
The ignition coil for an internal combustion engine according to claim 1.

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