JP2002048045A - Ignition coil device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ignition coil device for internal combustion engine capable of improving the service life of a power switch and the service life of the ignition coil device itself for internal combustion engine by buffering the stress generated by the expansion or the shrinkage of the thermosetting resin due to a temperature change acting on the power switch. SOLUTION: An iron core and coil assembly 11 formed by winding a primary coil 14 and a secondary coil 16 around an iron core 12 is housed in an insulating case 31, and a power switch 21 is housed in the insulating case 31, and the insulating case 31 is filled with the thermosetting resin 52 so as to fix the iron core and coil assembly 31 into the insulating case 31. In an ignition coil device for internal combustion engine with this structure, the power switch 21 is covered with the buffering resin 51.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molded type internal combustion engine ignition coil device for supplying a high voltage for generating a spark to, for example, a spark plug of an automobile engine.

[0002]

2. Description of the Related Art The above-mentioned conventional molded ignition coil device for an internal combustion engine accommodates an iron core and a coil assembly in which a primary coil and a secondary coil are wound around an iron core in an insulating case, and includes a power switch. It is housed in an insulating case, and a thermosetting resin such as an epoxy resin having an insulating property is filled in the insulating case to fix the iron core / coil assembly and the power switch in the insulating case.
Such an ignition coil device for an internal combustion engine is disclosed in, for example, Japanese Patent Application Laid-Open No. H10-196505 previously proposed by the present applicant.

[0003]

However, a thermosetting resin such as an epoxy resin has a larger expansion coefficient than an exterior molding resin of a power switch. Therefore, a stress at which the thermosetting resin expands or contracts due to a change in temperature is increased. By acting on the power switch, the power switch breaks down,
There is a risk of damage.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is intended to buffer a stress that a thermosetting resin expands or contracts due to a change in temperature from acting on a power switch. An object of the present invention is to provide an ignition coil device for an internal combustion engine that can extend the life of the power switch and further extend the life of the ignition coil device itself for the internal combustion engine.

[0005]

SUMMARY OF THE INVENTION According to the present invention, an iron / coil assembly in which a primary coil and a secondary coil are wound around an iron core is housed in an insulating case, and the power switch is housed in the insulating case. In an ignition coil device for an internal combustion engine that fixes an iron core / coil assembly and a power switch in an insulating case by filling the insulating case with a thermosetting resin having heat resistance, the thermosetting resin expands or contracts due to a change in temperature. The power switch is covered with a flexible buffering resin so that the applied stress acts on the power switch.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view of an ignition coil device for an internal combustion engine according to a first embodiment of the present invention, and FIG.
It is a longitudinal cross-sectional view corresponding to -X-ray. In FIG. 1, illustration of each resin is omitted.

In these figures, reference numeral 1 denotes an ignition coil device for an internal combustion engine, which includes an iron core / coil assembly 11, a power switch 21, and a synthetic resin insulation housing the iron core / coil assembly 11 and the power switch 21. Case 31
And a terminal 41 and a high-voltage terminal 42 attached to the insulating case 31 and an insulating and flexible material, such as a soft epoxy resin or a silicone resin, for insulating and fixing the power switch 21 in the insulating case 31. And the like, and an insulating thermosetting resin 52 for insulating and fixing the components of the core / coil assembly 11 in the insulating case 31.

The above-mentioned iron core / coil assembly 11 has, for example, an iron core 12 formed into a sun-shape by combining two parts, a part of the iron core 12 is inserted, and one end is provided in an insulating case 31. Primary coil bobbin 13 for closing the opening 32a, the primary coil 14 wound around the primary coil bobbin 13, and the primary coil 1
4 and a secondary coil 16 disposed outside of the motor. The power switch 21 has a configuration in which a power transistor as a power switching element is mounted on a heat sink and molded with resin.

The insulating case 31 is provided with an opening 32a closed at the bottom by the primary coil bobbin 13 and two through holes 32b through which the iron core 12 penetrates. A case main body 32 forming a housing part, and an auxiliary housing part 3 provided on one side surface of the case main body 32 and housing the power switch 21
3, a terminal seat 34 provided on one side surface of the auxiliary housing portion 33 and having a plurality of terminals 41 attached thereto, and a case body 3
2 and two cylindrical high-pressure towers 35 connected to the other side and to which high-voltage terminals 42 are attached.

The terminal 41 is inserted when the insulating case 31 is formed, and is integrated with the insulating case 31. The case main body (main housing portion) 32 and the auxiliary housing portion 33 are defined by a partition wall 33a lower than the peripheral wall.

Next, an example of how to assemble the ignition coil device 1 for an internal combustion engine will be described. First, the power switch 21
Is stored in the auxiliary housing portion 33 of the insulating case 31, and then the auxiliary housing portion 33 is filled with the buffering resin 51 almost up to the height of the partition wall 33a or until the power switch 21 is covered, and then cured. Is covered with a buffer resin 51. When the power switch 21 is covered with the buffer resin 51 in this way, the terminals of the power switch 21 are exposed since they will be connected to respective parts later.

Next, a winding is wound around the outer periphery of the primary coil 1.
4. The primary coil bobbin 13 on which the
6, the primary coil 14 is inserted into the case body 32
Then, one end of the primary coil bobbin 13 is fitted into the opening 32 a of the case main body 32, and the opening 32 a is closed by the primary coil bobbin 13. Then, the high-voltage terminal 42 is fitted into the high-voltage tower 35 from the upper side by using a slope in which the high-pressure tower 35 converges downward in a conical shape, as shown in FIG.

Next, both ends of the primary coil 14, both ends of the secondary coil 16, each terminal of the power switch 21, a plurality of terminals 41, and a high voltage terminal 42 are connected to form a predetermined circuit. Then, the end of each part of the iron core 12 is inserted into the primary coil bobbin 13 and the through hole 32b to be connected to each other, so that the insulating case 31 is filled with the thermosetting resin 52 to almost the height of the peripheral wall. After that, the assembly of the ignition coil device 1 for the internal combustion engine is completed.

As described above, according to the first embodiment of the present invention, the power switch 21 is covered with the buffering resin 51 having flexibility. The stress due to expansion or contraction is caused by the buffer resin 5
1, the power switch 21 is stressed by expansion or contraction of the thermosetting resin 52.
Will not break down or break. Therefore, the life of the power switch 21 can be extended, and further, the life of the ignition coil device 1 for an internal combustion engine can be extended.

FIG. 3 is a plan view of an ignition coil device for an internal combustion engine according to a second embodiment of the present invention, and FIG. 4 is a longitudinal sectional view corresponding to the line YY of FIG. The same or corresponding parts have the same reference characters allotted and description thereof will not be repeated. Note that FIG.
, The illustration of the thermosetting resin is omitted.

In these figures, reference numeral 61 denotes a housing for housing the power switch 21 and is formed in a bottomed cylindrical shape with one side opened, for example, a box shape.

Next, an example of how to assemble the ignition coil device 1 for an internal combustion engine will be described. First, after the power switch 21 is housed in the housing 61, the buffer resin 5 is
The power switch 21 is covered with the buffering resin 51 by filling and hardening 1 to almost the height of the peripheral wall. When the power switch 21 is covered with the buffer resin 51 in this way, the terminals of the power switch 21 are exposed since they will be connected to respective parts later.

Next, the housing 61 is housed in the auxiliary housing 33 of the insulating case 31. In addition, even if the storage body 61 is stored in the auxiliary storage part 33, the auxiliary storage part 33 is not filled with the buffer resin 51. Thereafter, assembly is performed in the same manner as in the first embodiment.

In the second embodiment, the same effects as in the first embodiment can be obtained.

In the first embodiment, after the power switch 21 is housed in the auxiliary housing 33,
The power switch 21 is covered with the buffering resin 51 by filling the buffering resin 51 with the buffering resin 51. In the first and second embodiments, since the entire periphery of the power switch 21 is covered with the buffering resin 51, a stress that causes the thermosetting resin 52 to expand or contract due to a change in temperature acts on the power switch 21. But the entire periphery of the power switch 21 is covered with a buffer resin 5.
Since the above-mentioned stress can be buffered without being covered with 1, the covering of the power switch 21 with the buffering resin 51 so that the above-mentioned stress acts on the power switch 21 means, for example, that the power switch 21 is a rectangular solid. Since the stress from all directions can be buffered by covering at least one of the opposing surfaces, that is, three or more surfaces with the buffer resin 51, the power switch 21 is covered with the buffer resin 51 in this manner. Say

[0021]

As described above, according to the present invention, since the power switch is covered with the flexible buffer resin, when the temperature changes, the stress due to expansion or contraction of the thermosetting resin is reduced. By being buffered by the buffer resin, the power switch does not break down or break due to stress caused by expansion or contraction of the thermosetting resin. Therefore,
The life of the power switch can be extended, and the life of the ignition coil device for the internal combustion engine can be extended.

[Brief description of the drawings]

FIG. 1 is a plan view of an ignition coil device for an internal combustion engine according to a first embodiment of the present invention.

FIG. 2 is a longitudinal sectional view corresponding to line XX in FIG.

FIG. 3 is a plan view of an ignition coil device for an internal combustion engine according to a second embodiment of the present invention.

FIG. 4 is a longitudinal sectional view corresponding to line YY of FIG. 3;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ignition coil device for internal combustion engines 11 Iron core / coil assembly 12 Iron core 13 Primary coil bobbin 14 Primary coil 16 Secondary coil 21 Power switch 31 Insulating case 32 Case body 32a Opening 32b Through hole 33 Auxiliary accommodating part 33a Partition wall 34 Terminal seat 35 High voltage Tower 41 Terminal 42 High voltage terminal 51 Buffer resin 52 Thermosetting resin 61 Container

Claims (1)

[Claims] An insulative thermoset having an iron core and a coil assembly in which a primary coil and a secondary coil are wound around an iron core is accommodated in an insulating case, and a power switch is accommodated in the insulating case. In an ignition coil device for an internal combustion engine in which the insulating case is filled with resin to fix the iron core / coil assembly and the power switch in the insulating case, a stress in which the thermosetting resin expands or contracts due to a change in temperature. The ignition coil device for an internal combustion engine, wherein the power switch is covered with a flexible buffer resin so that the power switch can act on the power switch.