JP2020021762A - Ignition coil for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ignition coil for an internal combustion engine capable of improving the insulating property of a resin composition constituting an insulating member and corresponding to high output. An ignition coil for an internal combustion engine is provided around a rod-shaped central core 2, a primary coil 3 provided around the central core 2, and a primary coil 3 at predetermined intervals, and the secondary coil 5 is provided. The inside of the housing case 9 includes a secondary bobbin 6 around which the bobbin is wound and an outer peripheral iron core 8 which is provided around the secondary bobbin 6 at a predetermined interval and magnetically couples the primary coil 3 and the secondary coil 5. It is fixed by an insulating member 10 which is arranged in the housing case 9 and filled inside the housing case 9. The insulating member 10 is a resin composition containing an acid anhydride and an epoxy resin, and has an equal amount ratio represented by the following formula of 0.5 to 0.8. Equal amount ratio = [acid anhydride added amount (g) / acid anhydride equivalent (g / eq)] / [epoxy resin added amount (g) / epoxy resin equivalent (g / eq)] [selection diagram] FIG.

Description

  The present invention relates to an ignition coil for an internal combustion engine that supplies a high voltage to generate a spark discharge in a spark plug of an automobile engine, for example.

  Conventionally, a center core, a primary bobbin provided around the center core and wound with a primary coil, a secondary bobbin provided around the primary bobbin and wound with a secondary coil, 2. Description of the Related Art There is known an ignition coil for an internal combustion engine in which an outer core provided around a bobbin and a permanent magnet provided between the center core and the outer core are disposed in a housing case (for example, Patent Document 1). ). In the ignition coil for the internal combustion engine of Patent Document 1, the entire primary bobbin together with the central iron core is disposed inside the outer peripheral iron core, and in order to ensure insulation between the primary coil and the secondary coil, the inside of the housing case is Sealed with insulating resin.

JP 2010-212395 A

As an insulating resin for sealing the inside of the housing case, a resin in which a filler is dispersed is used in order to cope with high output of an ignition coil for an internal combustion engine. The effect of the filler greatly changes depending on the type and concentration of the filler.
There is a demand for an ignition coil for an internal combustion engine used in a vehicle engine that can cope with higher output, and to improve the insulation of a resin composition constituting an insulating member while maintaining a desired function. That is a challenge.

  Accordingly, an object of the present invention is to provide an ignition coil for an internal combustion engine that can improve the insulating properties of a resin composition constituting an insulating member and can cope with high output.

The ignition coil for an internal combustion engine according to the present invention is provided with a rod-shaped first iron core, a primary coil provided around the first iron core, and provided at predetermined intervals around the primary coil, and the secondary coil is wound around the primary coil. The secondary bobbin and the second core that is provided at a predetermined interval around the secondary bobbin and magnetically couples the primary coil and the secondary coil are disposed inside the storage case, It is fixed by an insulating member filled inside, the insulating member is a resin composition containing an acid anhydride and an epoxy resin, the equivalent ratio represented by the following formula, from 0.5 0.8.
Equivalent ratio = [acid anhydride addition amount (g) / acid anhydride equivalent (g / eq)] / [epoxy resin addition amount (g) / epoxy resin equivalent (g / eq)]

  The ignition coil for an internal combustion engine according to the present invention is characterized in that the resin composition contains, as an inorganic filler, at least one of aluminum hydroxide, silica, and layered silicate.

  The ignition coil for an internal combustion engine according to the present invention is such that the distance between the primary coil and the high voltage output side of the secondary bobbin from the primary coil of the insulating member provided between the primary coil and the secondary coil is 0.8 mm to 2.0 mm. There is a feature.

  The ignition coil for an internal combustion engine according to the present invention is such that the distance between the primary coil and the high voltage output side of the secondary bobbin from the primary coil of the insulating member provided between the primary coil and the secondary coil is 0.3 mm to 0.8 mm. There is a feature.

  In the ignition coil for an internal combustion engine according to the present invention, the distance between the high voltage output side of the secondary coil and the second core of the insulating member provided between the secondary coil and the second core is from 2.0 mm to 3.0 mm. 0 mm.

  In the ignition coil for an internal combustion engine according to the present invention, the distance between the high voltage output side of the secondary coil and the second core of the insulating member provided between the secondary coil and the second core is from 1.0 mm to 2.0 mm. 0 mm.

An ignition coil for an internal combustion engine according to the present invention has a rod-shaped first iron core, a secondary bobbin around which a secondary coil provided around the first iron core is wound, and a predetermined space around the secondary coil. The primary bobbin around which the primary coil is wound, and the second core, which is provided at a predetermined interval around the primary bobbin and magnetically couples the primary coil and the secondary coil, are provided inside the housing case. The insulating member is disposed and fixed by an insulating member filled inside the storage case, wherein the insulating member is a resin composition containing an acid anhydride and an epoxy resin, and is an equivalent amount represented by the following formula. The ratio is between 0.5 and 0.8.
Equivalent ratio = [acid anhydride addition amount (g) / acid anhydride equivalent (g / eq)] / [epoxy resin addition amount (g) / epoxy resin equivalent (g / eq)]

In the ignition coil for an internal combustion engine according to the present invention, the insulating member filled in the housing case is a resin composition containing an epoxy resin and an acid anhydride, and this resin composition has an equivalent ratio represented by the following formula of 0. 0.5 to 0.8. With such an equivalent ratio, it is possible to suppress an increase in the viscosity of the resin composition and generation of voids (voids) in the resin composition, secure heat resistance of the insulating member, and improve insulation and durability. Can be raised. Therefore, the ignition coil for an internal combustion engine according to the present invention can cope with high output.
Equivalent ratio = [acid anhydride addition amount (g) / acid anhydride equivalent (g / eq)] / [epoxy resin addition amount (g) / epoxy resin equivalent (g / eq)]

1 is a sectional view of an ignition coil for an internal combustion engine according to an embodiment of the present invention. 1 is a partially enlarged sectional view of an internal combustion engine ignition coil according to an embodiment of the present invention.

The internal combustion engine ignition coil according to the present embodiment is used, for example, to supply a high voltage to generate spark discharge in a spark plug of an automobile engine.
An ignition coil for an internal combustion engine according to the present embodiment will be described with reference to FIGS.

  As shown in FIG. 1, an ignition coil 1 for an internal combustion engine according to the present embodiment includes a center core 2 as a first core, and a primary bobbin provided around the center core 2 and around which a primary coil 3 is wound. 4, a secondary bobbin 6 provided around the primary bobbin 4 and wound with a secondary coil 5, and an outer peripheral core 8 as a second core provided around the secondary bobbin 6. It has a configuration arranged inside a case (insulating case) 9. An outer core cover 7 is provided inside the outer core 8 along the outer core 8.

A resin composition is filled in a gap inside the storage case 9, and the resin composition is cured to form the insulating member 10. Since the resin composition fills the entire gap of the housing case 9, the insulating member 10 is provided between the primary coil 3 and the secondary bobbin 6, and between the secondary coil 5 and the outer core 8 (the outer core cover 7). It is formed at intervals.
The primary coil 3, the primary bobbin 4, the secondary coil 5, and the secondary bobbin 6 are insulated by filling the gap inside the storage case 9 with the insulating member 10, and these members are connected to the storage case 9. 9 is fixed inside.

  The center core 2 is a rod-shaped member, and a magnetic circuit is formed in the center core 2. For example, a circuit forming a closed magnetic circuit can be formed on the center iron core 2 by press-stacking a silicon steel plate. The center iron core 2 is housed in a primary bobbin 4, and a primary coil 3 is wound around the primary bobbin 4. For example, an enameled wire can be used for the primary coil 3.

  The secondary bobbin 6 is provided on the outer periphery of the primary bobbin 4 at a predetermined interval from the primary bobbin 4. A flange 11 is formed on the secondary bobbin 6, and a plurality of the flanges 11 are provided at predetermined intervals in the axial direction of the secondary bobbin 6. The secondary coil 5 is wound between the flanges 11, and an enameled wire can be used for the secondary coil 5, similarly to the primary coil 3.

  The outer core 8 is for returning the magnetic flux generated in the center core 2, and the center core 2 having the primary bobbin 4 and the secondary bobbin 6 is disposed inside the outer core 8.

The insulating member 10 is a resin composition containing an epoxy resin and an acid anhydride. The acid anhydride is contained as a curing agent for the epoxy resin.
As the epoxy resin, for example, an aromatic epoxy resin, a bisphenol-type epoxy resin, and a novolak-type epoxy resin can be used. On the other hand, as the acid anhydride, for example, phthalic anhydride, trimellitic anhydride, and pyromellitic anhydride can be used.

In the present embodiment, as the resin composition constituting the insulating member 10, one having an equivalent ratio R of an epoxy resin and an acid anhydride of 0.5 to 0.8 is used. This equivalence ratio R is expressed as in equation (1).
If the equivalent ratio R is less than 0.5, crosslinking of the epoxy resin becomes insufficient, and desired properties such as insulating properties and heat resistance of the insulating member 10 cannot be obtained, and durability may be reduced.
On the other hand, when the equivalence ratio R is larger than 0.8, the amount of unreacted acid anhydride increases, which adversely affects the insulating property of the insulating member 10 and cannot improve the durability.
Equivalent ratio R = [acid anhydride addition amount (g) / acid anhydride equivalent (g / eq)] / [epoxy resin addition amount (g) / epoxy resin equivalent (g / eq)] formula (1) )

The resin composition may further contain an inorganic filler. Aluminum hydroxide, silica, and layered silicate can be used for the inorganic filler, and the resin composition only needs to contain at least one of them.
As the layered silicate, mica (mica) or a modified mineral of mica can be used, and in order to obtain sufficient insulating properties, the particle diameter of the layered silicate is preferably 2 μm to 20 μm. The average particle diameter of the primary particles formed by the layered silicate is preferably smaller than the diameter of the enameled wires (electric wires) constituting the primary coil 3 and the secondary coil 5.

In the ignition coil 1 for an internal combustion engine, as shown in FIG. 2, between the primary coil 3 and the high voltage output side of the secondary bobbin 6 between the primary coil 3 and the insulating member 10 provided between the primary coil 3 and the secondary coil 5. The distance W1 is from 0.8 mm to 2.0 mm. Further, the distance W1 between the primary coil 3 of the insulating member 10 provided between the primary coil 3 and the secondary coil 5 and the high voltage output side of the secondary bobbin 6 may be set to 0.3 mm to 0.8 mm. it can.
The high voltage output side of the secondary coil 5 means the right side of the secondary coil 5 in FIG.

  Further, in the ignition coil 1 for an internal combustion engine, the outer core 8 (from the high voltage output side of the secondary coil 5 of the insulating member 10 provided between the secondary coil 5 and the outer core 8 (or the outer core cover 7)). Alternatively, the distance W2 between the outer core covers 7) is from 2.0 mm to 3.0 mm (FIG. 2). Further, the insulating member 10 provided between the secondary coil 5 and the outer core 8 (or the outer core cover 7) is provided between the high voltage output side of the secondary coil 5 and the outer core 8 (the outer core cover 7). The distance W2 can be from 1.0 mm to 2.0 mm.

Next, a method of manufacturing the ignition coil 1 for an internal combustion engine will be briefly described.
The method for manufacturing the ignition coil 1 for an internal combustion engine includes a resin composition adjusting step and a resin composition curing step.
In the resin composition adjusting step, an acid anhydride and an inorganic filler are blended with the epoxy resin, and the epoxy resin is agitated while being vacuum removed. The compounding amount of the acid anhydride is determined so as to be within the range of the equivalent ratio R in the above formula (1). The resin composition is used until the compounded substances are sufficiently dispersed.

In the resin composition curing step, the adjusted resin composition is filled in the housing case 9 and then heated. This heating is performed in a temperature range of 130 ° C. to 180 ° C. for a predetermined time, for example.
Since the primary coil 3, the secondary coil 5, and the like are provided inside the housing case 9, the primary coil 3, the secondary coil 5, and the like are heated and cured, so that the primary coil 3, the secondary coil 5, and the like can be formed as desired. Fixed in position.

  Next, the operation and effect of the internal combustion engine ignition coil 1 will be described.

In the ignition coil 1 for an internal combustion engine according to the present embodiment, the insulating member 10 to be filled is a resin composition containing an epoxy resin and an acid anhydride, and this resin composition is represented by the above (Formula 1). The equivalence ratio R is between 0.5 and 0.8.
By setting the equivalent ratio R in the range, it is possible to suppress an increase in the viscosity of the resin composition and the generation of voids (voids) in the resin composition, and to improve the insulation and durability of the insulating member 10. Can be.
Therefore, the internal combustion engine ignition coil 1 can cope with high output.

  The resin composition constituting the insulating member 10 of the ignition coil 1 for an internal combustion engine according to the present embodiment contains, as an inorganic filler, at least one layered silicate such as aluminum hydroxide, silica, and mica. . By containing the inorganic filler, the insulating property of the insulating member 10 can be further improved.

  In the ignition coil 1 for an internal combustion engine according to the present embodiment, since the insulation and durability of the insulating member 10 can be improved, the distance W1 from the primary coil 3 to the secondary bobbin 6 (secondary coil 5) is set to 0. The distance W2 from the secondary coil 5 to the outer core 8 (the outer core cover 7) can be set to 1.0 mm to 3.0 mm.

In the conventional ignition coil for an internal combustion engine, when the output is 40 kV, the distance W1 needs to be 1.5 mm, and when the output is 30 kV, the distance W1 needs to be 0.55 mm.
On the other hand, the ignition coil 1 for an internal combustion engine according to the present embodiment was usable when the output was 40 kV, the distance W1 was 1.2 mm, and when the output was 30 kV, the distance W2 was 0.4 mm.
From this, by using the insulating member 10 described in the present embodiment, the ignition coil 1 for an internal combustion engine can cope with high output and can be downsized.

As described above, the present embodiment has been described. In addition to the above, the configuration described in the above embodiment can be selected or changed to another configuration without departing from the gist of the present invention. .
For example, the primary coil 3 and the secondary coil 5 of the ignition coil 1 for an internal combustion engine described in the present embodiment may be configured to be reversed. That is, the ignition coil 1 for an internal combustion engine is provided at a predetermined interval around a secondary bobbin 6 around which a secondary coil 5 wound around a rod-shaped center iron core 2 is wound. A primary bobbin 4 around which the primary coil 3 is wound, and an outer peripheral core 8 provided at a predetermined interval around the primary bobbin 4 and magnetically coupling the primary coil 3 and the secondary coil 5 to the housing case 9. These members are arranged and fixed by an insulating member 10. Also in this case, the insulating member 10 is a resin composition containing an acid anhydride and an epoxy resin, and the equivalent ratio R represented by the formula (1) is 0.5 to 0.8.

1 Ignition coil for internal combustion engine 2 Central iron core (first iron core)
3 Primary coil 4 Primary bobbin 5 Secondary coil 6 Secondary bobbin 7 Outer core cover 8 Outer core 9 Housing case (insulating case)
Reference Signs List 10 Insulating member 11 Flange R Equivalent ratio W1, W2 Distance

Claims (7)

A rod-shaped first core, a primary coil provided around the first core, a secondary bobbin provided with a predetermined distance around the primary coil and wound with a secondary coil, A second core, which is provided at a predetermined interval around the next bobbin and magnetically couples the primary coil and the secondary coil, is disposed inside the storage case, and is filled in the storage case. An internal combustion engine ignition coil fixed by the insulating member,
The insulating member is a resin composition containing an acid anhydride and an epoxy resin,
The equivalent ratio represented by the following formula is 0.5 to 0.8,
An ignition coil for an internal combustion engine.
Equivalent ratio = [acid anhydride addition amount (g) / acid anhydride equivalent (g / eq)] / [epoxy resin addition amount (g) / epoxy resin equivalent (g / eq)] The resin composition contains, as an inorganic filler, at least one of aluminum hydroxide, silica, and layered silicate.
The ignition coil for an internal combustion engine according to claim 1, wherein: The distance between the primary coil and the high voltage output side of the secondary bobbin from the primary coil of the insulating member provided between the primary coil and the secondary coil is 0.8 mm to 2.0 mm,
The ignition coil for an internal combustion engine according to claim 1 or 2, wherein: The distance between the primary coil and the high voltage output side of the secondary bobbin from the primary coil of the insulating member provided between the primary coil and the secondary coil is 0.3 mm to 0.8 mm,
The ignition coil for an internal combustion engine according to claim 1 or 2, wherein: A distance between the high voltage output side of the secondary coil and the second core of the insulating member provided between the secondary coil and the second core is 2.0 mm to 3.0 mm;
The ignition coil for an internal combustion engine according to any one of claims 1 to 4, characterized in that: The distance between the second core and the high voltage output side of the secondary coil of the insulating member provided between the secondary coil and the second core is 1.0 mm to 2.0 mm,
The ignition coil for an internal combustion engine according to any one of claims 1 to 4, characterized in that: A rod-shaped first iron core, a secondary bobbin around which the secondary coil provided around the first iron core is wound, and a primary coil provided around the secondary coil at a predetermined interval. The primary bobbin and the second core, which is provided at a predetermined interval around the primary bobbin and magnetically couples the primary coil and the secondary coil, are disposed inside the storage case, An ignition coil for an internal combustion engine fixed by an insulating member filled inside the storage case,
The insulating member is a resin composition containing an acid anhydride and an epoxy resin,
The equivalent ratio represented by the following formula is 0.5 to 0.8,
An ignition coil for an internal combustion engine.
Equivalent ratio = [acid anhydride addition amount (g) / acid anhydride equivalent (g / eq)] / [epoxy resin addition amount (g) / epoxy resin equivalent (g / eq)]

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