JP3294547B2 - Ignition device for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ignition device for an internal combustion engine which is directly mounted on an internal combustion engine.

[0002]

2. Description of the Related Art Conventionally, an igniter is arranged in a case for accommodating a winding portion of an ignition coil and is covered with a hardening insulating resin in order to reduce the size. Have been.

[0003]

An ignition device for an internal combustion engine is used in an environment where high and low temperatures are repeatedly applied.
At this time, a thermal stress is generated in the igniter due to a difference in linear expansion coefficient between the igniter and the curable resin. Therefore, the conventional igniter in which the periphery of the igniter is covered with the curable insulating resin has a problem that the igniter is easily damaged due to thermal stress from the curable insulating resin.

It is an object of the present invention to reduce the size of an ignition device for an internal combustion engine and to reduce the thermal stress applied to the igniter from a hardening insulating resin.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides an ignition coil winding portion housed in a case,
An igniter disposed in the case for interrupting the primary current of the ignition coil; and an insulation filled and injected between the igniter and the ignition coil winding portion in the case to encapsulate the ignition coil winding portion and the igniter. An igniter for an internal combustion engine which is provided with a conductive resin and is directly connected to an ignition plug, characterized in that the igniter is provided with a buffer material which is brought into contact with the igniter in the insulating resin to prevent thermal stress on the igniter. The technical means called an ignition device for an internal combustion engine is adopted.

[0006]

According to the first aspect of the invention, since the igniter is disposed in the case accommodating the ignition coil winding portion, the size of the ignition device for the internal combustion engine can be reduced. In addition, the
The cushioning material, which is in contact with the igniter in the insulating resin to prevent thermal stress, prevents thermal stress on the igniter caused by a difference in linear expansion coefficient between the igniter and the insulating resin. Therefore, damage to the igniter due to thermal stress can be suppressed. Further, in the invention according to claim 2,
The igniter must prevent thermal stress from all sides.
Can be.

[0007]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 to 6, an ignition coil winding unit 2 including a primary coil 10 and a secondary coil 20;
And an ignition plug connection terminal 25 connecting one end of the primary coil to a head terminal of an ignition plug (not shown).
The mold type igniter 50 for interrupting the next current is housed in the same resin case 40, and the potting resin 60 is injected into the case 40 and hardened.

In the mold type igniter 50, a portion embedded in the potting resin 60 is over-coded with a thermoplastic elastomer 53 in order to prevent thermal stress. Further, a heat sink 55 for facilitating heat radiation of a power transistor (not shown), which is a component of the igniter 50, is assembled to the mold type igniter 50. It is arranged in the opening at the upper end of the case 40. A connector 30 for external connection is arranged and fixed on the upper side surface of the case 40, and the connection between the molded type igniter 50 and the ignition coil winding part 2 is performed by connecting the ignition coil winding part 2 to the lower terminal 31 of the connector 30. And
Each L formed on each upper terminal 32 so as to protrude from the igniter 50.
By connecting the letter-shaped terminals 51, they are electrically connected via the terminals 31 and 32 of the connector 30.

A heat sink 55 made of a U-shaped metal plate
4 to 6 for positioning with the igniter 50.
As shown in the figure, a projection 58 is provided in the hole 52 formed in the igniter 50, and two projections 56, 57 extending parallel to the outer periphery of the igniter 50 for positioning with the outer periphery of the igniter 50. Is provided.

When the heat sink 55 to which the igniter 50 is attached is put into the case 40, a plurality of ribs 42 extending in the vertical direction are integrally formed on the inner peripheral surface of the case 40 as shown in FIGS. Have been. Each upper terminal 32 of the connector 30 has an igniter 50.
In consideration of the clearance at the time of assembling, as shown in FIG. 3, each long hole 35 is formed so that each L-shaped terminal 51 of the igniter 50 can be easily inserted.

In the above configuration, when the power transistor of the mold type igniter 50 is turned off, a current flowing through the primary coil 10 is cut off, and a high voltage is generated in the secondary coil 20. And this secondary coil 2
The high voltage generated at 0 is directly applied to the head terminal of the spark plug via the spark plug fitting 25, whereby the spark plug generates a spark discharge in the combustion chamber of the internal combustion engine.

In addition, ON / OFF of the power transistor
The heat generated in the mold type igniter 50 is released to the air through the heat sink 55. Thereby, the igniter 50 and the ignition coil winding part 2 are compactly housed in the same case 40 without disturbing the heat radiation, and the mountability of the ignition device to the internal combustion engine is improved.

In the above embodiment, the mold type igniter 50 is overcoated with the thermoplastic elastomer 53. In the embodiment shown in FIG.
After the coil potting resin 60 is injected and hardened to the upper portion of the ignition coil winding portion 2 in the case 40, the mold type igniter 50 is stored in the case 40 and connected to the upper terminal 32 of the connector 30. And case 4
Around the mold type igniter 50 in the area 0, a soft resin 70 for preventing thermal stress is injected and hardened.
It consists of times potting.

In the above-described embodiment, the igniter 50 and the ignition coil winding section 2 are connected via the connection terminals 31 and 32 of the external connection connector 30. The connection with the igniter 50 may be made directly by a connection terminal different from the external connection connector 30 .

[0015]

As described above, according to the present invention, since the ignition coil winding portion and the igniter are housed in the same case and sealed with potting resin, the size of the ignition device can be reduced. it can. Further, the thermal stress received by the igniter from the curable potting resin can be prevented by the thermal stress preventing means. For this reason, breakage of the igniter is suppressed, and excellent environmental resistance is obtained.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of the device of the present invention.

FIG. 2 is a plan view showing one embodiment of the device of the present invention.

FIG. 3 is a plan view showing a state before potting resin injection in the above embodiment.

FIG. 4 is a perspective view showing an assembled state of the igniter and the heat sink in the embodiment.

FIG. 5 is a perspective view showing a heat sink in the embodiment.

FIG. 6 is a perspective view showing an igniter in the embodiment.

FIG. 7 is a longitudinal sectional view showing another embodiment of the device of the present invention.

[Explanation of symbols]

 2 Ignition coil winding part 10 Primary coil 20 Secondary coil 30 Connector for external connection 31 Lower terminal 32 Upper terminal 40 Case 50 Igniter 53 Thermoplastic elastomer 55 Heat sink

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Noboru Nagase 1-1-1, Showa-cho, Kariya-shi, Aichi Prefecture Inside DENSO Corporation (56) References JP-A-63-120863 (JP, A) (JP, U) Japanese Utility Model Showa 57-132424 (JP, U)

Claims (6)

(57) [Claims] 1. An ignition coil winding part housed in a case, an igniter arranged in the case for interrupting a primary current of the ignition coil, and the igniter and the ignition coil winding part in the case. An ignition device for an internal combustion engine, which is injection-hardened between the ignition coil winding portion and an insulating resin for enclosing the igniter, and is directly connected to a spark plug , wherein the igniter is disposed within the insulating resin.
An ignition device for an internal combustion engine, comprising: a cushioning member that is in contact with the igniter to prevent thermal stress on the igniter. (2) The cushioning material is over the igniter
The internal combustion engine according to claim 1, wherein the internal combustion engine is coated.
Ignition device. 3. The ignition device for an internal combustion engine according to claim 1, wherein said cushioning material has rubber elasticity. 4. The ignition device for an internal combustion engine according to claim 1, wherein said cushioning material is a thermoplastic elastomer which overcoats the igniter. 5. The ignition device for an internal combustion engine according to claim 1, wherein the buffer material is a soft resin that overcoats the igniter. 6. A connector for external connection is fixed to an upper portion of the case, and the connector is provided with terminals respectively connected to the ignition coil winding portion and the igniter, and the ignition is connected via the terminals. The ignition device for an internal combustion engine according to any one of claims 1 to 5, wherein the coil winding portion and the igniter are electrically connected.