JPH0882274A - Ignition device for internal combustion engine - Google Patents

Abstract

PURPOSE: To prevent progress of separation of interface between a sealing material and the primary terminal, and to prevent the generation of cracks and split caused in the sealing material. CONSTITUTION: An ignition coil comprising the primary coil for generating low voltage and the secondary coil for converting the low voltage generated by the primary coil to high voltage, and a printed circuit board 30 where an ignition circuit for feeding a current to the primary coil is arranged are stored in a case. The fitting part of the primary terminal 40 for feeding a current to the ignition circuit to the counterpart terminal is disposed in such a manner as to be projected over a sealing material 60 formed by a thermosetting resin, which is filled in an opening of the case, and a stepped part having a flat part 41 parallel to the upper surface 61 of the sealing material 60 is provided in the substantially central part of the primary terminal 40, which is filled with the sealing material 60.

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 having an ignition coil and an ignition circuit housed in a case,
In particular, it relates to the shape and structure of the terminal of the ignition device for an internal combustion engine.

[0002]

2. Description of the Related Art Conventionally, as an ignition device of this kind for an internal combustion engine, an ignition circuit is arranged and a printed circuit board on which a flat primary terminal made of a metal material such as brass is installed and an ignition coil are integrated. After housing in a case, the liquid thermosetting resin is injected into the upper surface of the case so that the mating part of the primary terminal with the mating terminal is exposed, and the resin is heated and cured, It is known that the upper surface of the case is molded with a sealing material made of a curable resin. In the case where the top surface of the case is molded with this sealing material, it is caused by stress due to repeated heating and cooling, that is, due to thermal stress strain due to the difference in linear expansion coefficient between the molded resin and the metal material of the primary terminal. As a result, there occurs a phenomenon that interfacial peeling progresses at the interface between the molded resin and the primary terminal.

When the phenomenon that the interface separation progresses occurs, when the ignition device for an internal combustion engine is exposed to water, water enters the ignition circuit from the separation interface, resulting in a malfunction of the ignition circuit. It was Therefore, as shown in FIG. 10, a coating layer 71 of a flexible resin is provided in a portion of the flat plate-shaped primary terminal 70 that contacts the sealing material, and the thermal stress strain is reduced by the coating layer 71. It was considered to prevent interfacial peeling.

[0004]

As described above, when the coating layer 71 made of a flexible resin is provided on the portion of the flat plate-shaped primary terminal 70 that comes into contact with the sealing material, the coating layer 71 and the sealing material are separated from each other. The peeling at the interface can be prevented. However, since the coating layer 71 is made of a flexible resin and the flat plate-shaped primary terminal 70 is made of a metal material, heat generated based on a difference in linear expansion coefficient between these different materials is used. Due to the stress strain, the interface peeling occurs at the interface between these different materials, that is, at the interface between the coating layer 71 and the flat primary terminal 70.

Further, since the flat plate-shaped primary terminal 70 has no rigidity against an external load when it is assembled with the counterpart terminal or when the product is dropped, these external loads are applied to the flat plate-shaped primary terminal 70. When it is added to the plate, the flat primary terminal 70 is bent or deformed. Then, the flat primary terminal 70 is bent or deformed, which causes a problem that the sealing material is cracked or cracked. Therefore, the present invention has been made in view of the above problems,
Provided is an ignition device for an internal combustion engine, which prevents progress of interfacial peeling between a sealing material and a primary terminal due to thermal stress strain and prevents cracks and cracks generated in the sealing material due to deformation of the primary terminal. The purpose is to do.

[0006]

SUMMARY OF THE INVENTION The present invention is directed to a case having an opening, a primary coil for generating a low voltage by a self-induction action of an electric current stored in the case, and a mutual induction action of the primary coil. An ignition coil consisting of a secondary coil that converts a low voltage generated in the primary coil into a high voltage by the above, and a printed circuit board in which an ignition circuit that supplies current to the primary coil of the ignition coil housed in the case is arranged,
Ignition device for internal combustion engine having a primary terminal connected to the ignition circuit and serving as a current supply terminal to the ignition circuit, and a secondary terminal connected to the ignition coil and serving as a high-voltage supply terminal output from the ignition coil The first feature of the configuration of the present invention is that it protrudes from a sealing material made of a thermosetting resin filled in an opening of a case accommodating an ignition coil and a printed circuit board, and is a counterpart terminal of the primary terminal. And a step portion having a flat portion parallel to the upper surface of the sealing material is provided in the portion of the primary terminal to be filled with the sealing material.

A second characteristic feature of the present invention is that a cutout is provided in a flat portion parallel to the upper surface of the sealing material on the stepped portion of the primary terminal. Furthermore, a third feature of the configuration of the present invention resides in that bent portions having an L-shaped cross section are provided at both ends of the primary terminal in the longitudinal direction, and a fourth feature of the configuration of the present invention. The feature is that bent portions having an L-shaped cross section are provided at both end portions in the longitudinal direction of the primary terminal in the portion filled with the sealing material of the above-mentioned primary terminal.

[0008]

In the present invention configured as described above, the fitting portion of the primary terminal with the mating terminal is arranged so as to project from the sealing material, and the portion of the primary terminal filled with the sealing material is arranged. Since a step portion having a flat portion parallel to the upper surface of the sealing material is provided, this step portion allows
It becomes possible to change the direction of receiving thermal stress strain. Then, by changing the direction in which the thermal stress strain is applied, it is possible to prevent the progress of interfacial peeling at the interface between the primary terminal and the sealing material, and prevent the occurrence of malfunction of the ignition circuit due to water exposure. become able to.

Further, since the creepage distance at the interface between the primary terminal and the sealing material can be increased by providing the above-mentioned step portion, peeling at all interfaces between the primary terminal and the sealing material, that is, Thus, it becomes possible to lengthen the period until the entire surface is peeled off, which brings about a special effect that the ignition device for an internal combustion engine of this kind has a long life. Further, by providing such a stepped portion, the position where the primary terminal is pulled out from the printed board can be changed. If the position where the primary terminal is pulled out from the printed circuit board can be changed, it becomes possible to increase the distance between the circuit element arranged on the printed circuit board and the primary terminal, and malfunction of the ignition circuit due to water exposure. It becomes possible to further prevent the occurrence of.

If a notch is provided in a flat portion parallel to the upper surface of the sealing material of the stepped portion, an upper surface of the flat portion parallel to the upper surface of the sealing material of the stepped portion is provided through this notch. Since the lower surface and the lower surface are in communication with the sealing material, the thermal stress strain is reduced, so that it is possible to prevent the progress of interfacial peeling in the flat portion parallel to the upper surface of the sealing material at this step. Become. In addition, if a strength reinforcement is provided in a part of the primary terminal in the longitudinal direction, the strength of the primary terminal is increased by this strength reinforcement, and the primary terminal becomes rigid. Bending and deformation can be prevented.

Further, as the above-mentioned strength reinforcing portion, bent portions having an L-shaped cross section are provided at both end portions in the longitudinal direction of the primary terminal, and the bent portions having the L-shaped cross section are extended to a portion filled with the sealing material. If it is installed outside, even if an external load is applied, it is possible to prevent bending and deformation of the part filled with the sealing material, and to prevent cracks and cracks in the sealing material caused by the external load. It has the special effect of becoming.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the ignition device for an internal combustion engine of the present invention will be explained based on the drawings. 1 (a) and 1 (b) are views showing the overall configuration of an embodiment of an ignition device for an internal combustion engine of the present invention. FIG. 1 (a) shows a front view and FIG. 1 (b) shows a case. It is the side view seen through. As shown in FIGS. 1A and 1B, the internal combustion engine ignition device of the present invention has an opening 11
And a case 10 having a
A primary coil (not shown) that generates a low voltage (for example, 200 to 300 V) by a self-induction action by the supplied current, and a low voltage (for example, 200 V) that is generated in the primary coil by a mutual induction action with the primary coil. ~ 300V) to a high voltage (for example, 20,000 to 30,000V) secondary coil (not shown) ignition coil 20 composed of
A printed circuit board 30 in which an ignition circuit for supplying a current to the primary coil of the ignition coil 20 is housed in the case 10, and a terminal for supplying a current to the ignition circuit connected to the ignition circuit via a conductive wire. The primary coil 40 and the ignition coil 20 are connected to the ignition coil 20 via a conductive wire.
And a secondary terminal 50 serving as a supply terminal for a high voltage output from the secondary coil.

The ignition coil 20 is composed of a core 21 made of a magnetic material such as iron and laminated with iron plates having a high magnetic permeability, and a bobbin formed by inserting the core 21 into the center and molding the insulating material such as synthetic resin. 22 and a secondary coil (not shown) are wound on the core 21, and a primary coil (not shown) is wound on the secondary coil.

The printed circuit board 30 has a capacitor 31,
A capacitor discharge type ignition circuit in which a circuit element such as a diode 32 is mounted is arranged, and a hole through which the core 21 of the ignition coil 20 penetrates is provided. A sealing material made of a thermosetting resin, which will be described later, is filled in the upper part of the printed circuit board 30 to prevent the circuit elements such as the diode 32 from being destroyed by the contracting force of the thermosetting resin during curing. To this end, a protective coating layer 33 (hatched portion in FIGS. 1A and 1B) made of a flexible resin, such as silicon rubber, is provided above the circuit element such as the diode 32. .

These ignition coil 20 and printed circuit board 3
For example, in the opening 11 of the case 10 storing 0 and
The ignition coil 2 is filled with a sealing material 60 (see FIG. 2) made of a thermosetting resin having a high withstand voltage such as epoxy resin, phenol resin, urea resin and polyurethane resin.
0 and the printed circuit board 30 are liquid-tightly sealed with the outside of the case 10. Here, the primary terminal 40 is connected to the ignition circuit through a conductive wire and serves as a terminal for supplying a current to the ignition circuit, and is made of, for example, a material such as brass having good conductivity and high mechanical strength. The metal plate is formed into a predetermined shape. The shape of the primary terminal 40 of this embodiment is shown in FIG.

In FIG. 3, a portion 40b (FIG. 3) of the primary terminal 40 where the sealing material 60 (see FIG. 2) is filled.
(A) (b) between the dashed line A, B) in the substantially central portion,
A step portion formed by bending the substantially central portion into an L-shaped cross section to form a flat portion 41 parallel to the upper surface 61 of the sealing material 60 is provided. Further, the flat portion 41 is provided with a cutout portion 42 formed by punching or the like.
Further, the both side ends of the primary terminal 40 extending to the portion 40b filled with the sealing material 60 in the longitudinal direction are formed by bending the both side ends in the longitudinal direction of the primary terminal 40 into an L-shaped cross section. Bent portions 43, 43 having an L-shaped cross section are provided.

The mating portion 40a of the primary terminal 40 with the mating terminal (not shown) is fitted with a protrusion provided on the mating terminal when the mating terminal is mated with the primary terminal 40. A matching hole 44 is provided. Also, the lower portion 40c of the primary terminal 40
A connecting portion 45 for connecting a conducting wire (not shown) connected to the ignition circuit is provided on the one-dot chain line B in FIGS. 3A and 3B, that is, the portion below the printed circuit board 30. ing.

As described above, in this embodiment, the mating portion 40a of the primary terminal 40 with the mating terminal is arranged so as to project from the sealing material 60, and the sealing material 60 of the primary terminal 40 is filled. Part 40b
Since the step portion having the flat portion 41 parallel to the upper surface 61 of the sealing material 60 is provided, the step portion can change the direction in which the thermal stress strain is applied. And
By changing the direction in which thermal stress strain is applied, it is possible to prevent the progress of interfacial peeling at the interface between the primary terminal 40 and the sealing material 60, and prevent the occurrence of malfunction of the ignition circuit due to water exposure. become able to.

Further, by providing the stepped portion having the flat portion 41, the creepage distance between the primary terminal 40 and the sealing material 60 can be lengthened, and at all the interfaces between the primary terminal 40 and the sealing material 60. Of the internal combustion engine can be extended, and thus the ignition device for an internal combustion engine of this kind has a long service life. Further, by providing the stepped portion having such a flat portion 41, the position where the primary terminal 40 is pulled out from the printed circuit board 60 can be changed by the length of the flat portion 41 (D in FIG. 2). In this way, the position where the flat board 41 is pulled out from the printed circuit board 60 is set to the length (see FIG. 2).
If it becomes possible to change only D), the distance between the circuit element (34 in FIG. 2) arranged on the printed board 60 and the primary terminal 40 (D in FIG. 2) can be lengthened. It is possible to further prevent the occurrence of malfunction of the ignition circuit due to water.

Further, since the flat portion 41 is provided with the cutout portion 42, the flat portion 41 is provided through the cutout portion 42.
Since the upper and lower sealing members 60 communicate with each other and the thermal stress strain is reduced, it is possible to prevent progress of interfacial peeling in the flat portion 41.

Further, since bent portions 43, 43 having an L-shaped cross section are provided at both end portions in the longitudinal direction of the primary terminal 40 so as to extend to the portion 40b filled with the sealing material 60, the L-shaped cross section is provided. By the bent portions 43, 43, the strength of the primary terminal 40 is increased, and the primary terminal 40 has rigidity, so that the primary terminal 40 can be prevented from being bent or deformed due to an external load. Further, due to the bending and deformation of the primary terminal 40, the sealing material 6
The special effect of being able to prevent the occurrence of cracks, cracks, etc. that occur at 0 is also produced.

The shape and structure of the primary terminal 40 can be modified in various ways other than those shown in the above embodiment. Hereinafter, these modified examples will be described with reference to FIGS. 4 to 9. 4 to 9, the same reference numerals as those in the above-mentioned embodiment are the same as those in the above-mentioned embodiment, and the description thereof will be omitted.

Modification 1 In this first modification, the shape of the reinforcing portion is modified in order to increase the mechanical strength of the primary terminal 40 and add rigidity to the primary terminal 40. FIG.
Shows a first modified example of the present embodiment. In the first modified example, a punched-out portion 43a is formed by punching-molding in a substantially central portion above the step portion having the flat portion 41 of the primary terminal 40. are doing. By providing the punched-out portion 43a, the primary terminal 40 has a shape that is unlikely to be deformed by an external force, and it is possible to prevent the occurrence of cracks, cracks and the like in the sealing material 60.

Modification 2 In this second modification as well, the structure of the reinforcing portion is modified in order to increase the mechanical strength of the primary terminal 40 and add rigidity to the primary terminal 40. Figure 5
Shows a second modified example of the present embodiment, and in the second modified example, at least the sealing material 60 of the primary terminal 40.
The thickness of the portion 46 below the upper surface 61 (see FIG. 2) of
The plate thickness of the upper portion 47 is made thicker than this, so that the structure is not easily deformed by an external force.

Modification 3 In the third modification, the length of the flat portion of the primary terminal 40 is increased to increase the length of the primary terminal 40 and the sealing material 60.
To increase the creepage distance between and. FIG. 6 shows a third modification of the present embodiment. In the third modification, a flat portion 41a having a length L larger than the length D of the flat portion 41 of the above-described embodiment is provided. Especially. By providing such a long flat portion 41a, the primary terminal 4
The creepage distance between the sealing material 60 and the sealing material 60 becomes long, and the occurrence of malfunction of the ignition circuit due to water exposure can be further prevented.

Modification 4 In this fourth modification as well, the length of the flat portion of the primary terminal 40 is increased to increase the length of the primary terminal 40 and the sealing material 60.
To increase the creepage distance between and. FIG. 7 shows a fourth modified example of the present embodiment. In the fourth modified example, the creeping distance between the flat portion 41 and the sealing material 60 of the above-described embodiment, that is, the length D of the flat portion 41. This is because the bent portion 41c is provided on the flat portion 41b in order to make the creepage distance longer.
By thus forming the flat portion 41b provided with the bent portion 41c, the creepage distance between the primary terminal 40 and the sealing material 60 is further lengthened, and the occurrence of malfunction of the ignition circuit due to water is further prevented. become able to.

Modified Example 5 FIG. 8 shows a fifth modified example of the present embodiment. In the fifth modified example, the flat portion 41 and the sealing material 60 of the above-described embodiment are shown.
In order to make the creepage distance longer than the creepage distance, that is, the length D of the flat portion 41, the flat portion 41d has a constricted portion 41e,
41f is provided. Thus, the constricted portion 41
By using the flat portion 41d provided with e and 41f, the creepage distance between the primary terminal 40 and the sealing material 60 is further lengthened, and the occurrence of malfunction of the ignition circuit due to water exposure can be further prevented. Become.

Modified Example 6 FIG. 9 shows a sixth modified example of this embodiment. In this sixth modified example, the primary terminal 40 is provided in order to increase the creepage distance between the primary terminal 40 and the sealing material 60. The bent portions 47a and 47b are provided above the flat portion 41 of FIG. By thus forming the bent portion 47a, 47b on the upper portion 47, the primary terminal 40 and the sealing material 6
The creepage distance to 0 becomes longer than that, and it becomes possible to further prevent the occurrence of malfunction of the ignition circuit due to water exposure.

[Brief description of drawings]

FIG. 1 is a diagram showing an overall configuration of an embodiment of the present invention,
(A) is a front view, (b) is a side view seen through the case.

FIG. 2 is an enlarged view of a portion A of FIG.

3A and 3B are diagrams showing the shape of a primary terminal according to an embodiment of the present invention, FIG. 3A is a front view, FIG. 3B is a side view, and FIG. 3C is a top view.

FIG. 4 is a view showing a shape of a first modification of the primary terminal of the embodiment of the present invention, (a) is a front view, and (b) is a front view.
Is a side view.

FIG. 5 is a diagram showing a shape of a second modification of the primary terminal of the embodiment of the present invention, (a) is a front view, and (b) is a view.
Is a side view.

FIG. 6 is a view showing the shape of a third modification of the primary terminal of the embodiment of the present invention, (a) is a front view, and (b) is a front view.
Is a side view.

FIG. 7 is a view showing the shape of a fourth modification of the primary terminal of the embodiment of the present invention, (a) is a front view, and (b).
Is a side view.

FIG. 8 is a view showing the shape of a fifth modification of the primary terminal of the embodiment of the present invention.

FIG. 9 is a diagram showing the shape of a sixth modification of the primary terminal of the embodiment of the present invention.

FIG. 10 is a view showing a shape of a primary terminal of a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Case, 20 ... Ignition coil, 30 ... Printed circuit board, 40 ... Primary terminal, 41 ... Flat part, 42 ... Notch part, 43 ... L-shaped cross-section bent part, 50 ... Secondary terminal, 60 ... Sealing material .

Claims (7)

[Claims] 1. A case having an opening, a primary coil housed in the case and generating a low voltage by self-induction by a supplied current, and a primary coil generated by the mutual induction of the primary coil. An ignition coil comprising a secondary coil for converting the low voltage into a high voltage, a printed circuit board having an ignition circuit housed in the case, the ignition circuit supplying current to the primary coil of the ignition coil, and the ignition circuit. Ignition for internal combustion engine having a primary terminal connected to serve as a current supply terminal to the ignition circuit, and a secondary terminal connected to the ignition coil to serve as a high-voltage supply terminal output from the ignition coil An apparatus, wherein the ignition coil and the printed circuit board are projected from a sealing material made of a thermosetting resin filled in an opening of a case accommodating the printed circuit board, The mating portion of the next terminal with the mating terminal is arranged, and a step portion having a flat portion parallel to the upper surface of the sealing material is provided in the portion of the primary terminal where the sealing material is filled. Ignition device for internal combustion engine. 2. The ignition device for an internal combustion engine according to claim 1, wherein a cutout portion is provided in the flat portion. 3. The ignition device for an internal combustion engine according to claim 1, wherein a strength reinforcing portion is provided in a part of the primary terminal in the longitudinal direction. 4. The ignition device for an internal combustion engine according to claim 3, wherein the strength reinforcing portion is formed by providing a bent portion having an L-shaped cross section at both end portions in the longitudinal direction of the primary terminal. 5. The ignition device for an internal combustion engine according to claim 3, wherein the strength reinforcing portion is formed by stamping in a substantially central portion in the longitudinal direction of the primary terminal. 6. The ignition device for an internal combustion engine according to claim 3, wherein the strength reinforcing portion is formed by providing a thick portion on the primary terminal. 7. The ignition device for an internal combustion engine according to claim 4, wherein the bent portion having an L-shaped cross section is provided so as to extend to a portion filled with the sealing material.