JP6933592B2 - Igniter - Google Patents

Description

The present invention relates to an igniter.

An ignition device for an internal combustion engine provided in an automobile engine includes an igniter that energizes and cuts off a current flowing through an ignition coil. The igniter is required to have a configuration that can be easily assembled. In Patent Document 1, the upper surface is opened, and a connector portion for accommodating a low-voltage terminal is provided on one side, and a high-voltage cylinder portion for accommodating a high-voltage terminal is provided on a lower portion. The coil, the secondary coil, and the iron core that magnetically couples the secondary coil and the primary coil are housed, and the insulating resin is injected to maintain the insulation between the housed parts, and the inside of the cylinder of the high-voltage cylinder part. In an ignition coil for an internal combustion engine configured by inserting a high-voltage terminal and a resistor that reduces discharge noise, an inwardly projecting portion that supports the lower surface of the resistor is provided inside the cylinder of the high-voltage cylinder, and a resistor is provided. An ignition coil for an internal combustion engine, characterized in that the upper surface of the body is closed with a high-pressure terminal, is disclosed.

Japanese Unexamined Patent Publication No. 2011-035019

In the invention described in Patent Document 1, efficient assembly cannot be performed when a bare chip is used.

The igniter according to the first aspect of the present invention is an igniter including a conductive frame and a bare chip fixed to the conductive frame by a conductive adhesive, and the conductive frame is formed from a base portion and the base portion. The contact facing surface, which is provided with a convex portion protruding toward the bare chip side and is a surface of the convex portion in contact with the bottom surface of the bare chip, is octagonal , and the conductive adhesive is applied to the contact facing surface. The base portion is a groove formed in the conductive frame, and the contact facing surface includes four alternately long sides and four short sides, and the short side is provided from the center of the contact facing surface. distance to is longer than the distance from the center of the contact facing surface to the long side, the distance from the short sides to the edge of the bottom surface of the bare chip, the distance from the long sides to the edge of the bottom surface of the bare chip Shorter than.

According to the present invention, efficient assembly is possible when a bare chip is used.

External view of the ignition device 1 Cross-sectional view of the range surrounded by the dotted line in FIG. FIG. 3A is an external view of the igniter 6, and FIG. 3B is a diagram in which the mold resin 6a is removed from FIG. 3A. Enlarged view near bare chip 6f The figure which shows the shape and structure of a bare tip 6f VI-VI sectional view of FIG. FIG. 7A is a diagram showing the shape of the contact facing surface 6ht in the present embodiment, and FIG. 7B is a diagram showing the shape of the contact facing surface P of the comparative example. The figure which shows the comparison of the spread of the conductive adhesive 6g in an Example and a comparative example. The figure which shows the comparison of the spread of the conductive adhesive 6g in an Example and a comparative example. The figure which shows the outer shape of the contact facing surface 6ht in the modification 2. External view of the convex portion 6h in the modified example 3 The figure which shows the relationship between the contact facing surface 6ht of the convex part 6h and the bottom surface 6fb of a bare tip 6f in the 2nd Embodiment.

-First Embodiment-
Hereinafter, the first embodiment of the igniter according to the present invention will be described with reference to FIGS. 1 to 9.

(Appearance of ignition device 1)
FIG. 1 is an external view of an ignition device 1 incorporating an igniter according to the present invention. The ignition device 1 is mounted on a device having an internal combustion engine, for example, a vehicle. FIG. 2 is a cross-sectional view of a range surrounded by a dotted line in FIG. The coil case 2 of the ignition device 1 for an internal combustion engine is integrally formed with an external connection connector 2a and an external connection connector terminal 2b. The coil 3 and the igniter 6 are housed inside the coil case 2 and fixed by the casting resin 4.

(Appearance of igniter 6)
FIG. 3A is an external view of the igniter 6. The igniter 6 has a configuration in which the internal connection terminal 6b projects from the mold resin 6a. FIG. 3B is a diagram in which the mold resin 6a is removed from FIG. 3A. The igniter 6 includes a thin plate-shaped conductive frame 6c formed by extrusion processing and having an internal connection terminal 6b, an electronic component 6d, and a bare chip 6f. The conductive frame 6c forms a wiring structure, and the electronic component 6d and the bare chip 6f are connected by the conductive adhesive 6g to form a control circuit via the connecting wire 6e.

(Near bare chip 6f)
FIG. 4 is an enlarged view of the vicinity of the bare chip 6f. However, in FIG. 4, the connection wire 6e is not shown. The bare chip 6f is connected to the conductive frame 6c by the conductive adhesive 6g. A groove 6j is formed around the bare tip 6f. Although the outer circumference of the groove 6j is circular here, the shape of the outer circumference of the groove 6j is not limited to a circle and may be a polygon. FIG. 4 shows a state in which the bare chip 6f is connected to the conductive frame 6c and is therefore hidden by the bare chip 6f. However, the conductive frame 6c has a convex portion 6h on the inner peripheral portion of the groove 6j as described later.

FIG. 5 is a diagram showing the shape and configuration of the bare chip 6f. The bare chip 6f is connected to the conductive frame 6c in the posture shown in FIG. The bare chip 6f is a hexahedron having a rectangular parallelepiped shape. The bare chip 6f includes a bottom surface 6fb facing the conductive frame 6c, a top surface 6ft which is a surface opposite to the bottom surface 6fb, and a side surface 6fs which is the remaining four surfaces in contact with the bottom surface 6fb. However, in FIG. 5, two surfaces, the bottom surface 6fb and the side surface 6fs, are hidden. The bare chip 6f has a contact point with the connecting wire 6e on the upper surface 6ft.

Further, the bare chip 6f does not have an insulator on the side surface 6fs. Therefore, if 6 g of the conductive adhesive comes into contact with the side surface 6 fs, an electrical short circuit occurs, which causes a problem. Since the igniter 6 in the present embodiment has a structure in which this short circuit is unlikely to occur due to a device described later, efficient assembly is possible, and further, a short circuit is unlikely to occur after assembly. Although it is possible to reduce the possibility of short circuit by reducing the amount of the conductive adhesive 6g used for the bare chip 6f, the adhesive strength between the bare chip 6f and the conductive frame 6c is reduced, so that the conductive adhesive is adhered. It is not realistic to reduce the amount of 6g of agent.

(Cross section)
FIG. 6 is a cross-sectional view of the vicinity of the bare chip 6f connected to the conductive frame 6c, in other words, a cross-sectional view of VI-VI of FIG. The conductive frame 6c includes a convex portion 6h, a groove 6j, and a base portion 6k. The base portion 6k is a so-called bottom portion of the groove 6j. The upper end of the convex portion 6h, that is, the surface that comes into contact with the bare chip 6f via the conductive adhesive 6g is hereinafter referred to as a contact facing surface 6ht. The area of the contact facing surface 6ht is smaller than the bottom surface 6fb of the bare chip 6f, and the contact facing surface 6ht is shorter than the bottom surface 6fb not only in the width dimension shown in FIG. 6 but also in the depth direction. The convex portion 6h has a role of mechanically supporting the bare chip 6f, and although not shown in FIG. 6, since the connection wire 6e described above is connected to the bare chip 6f, the area of the contact facing surface 6ht Is not preferable. Further, the height of the contact facing surface 6ht in the vertical direction in FIG. 6 is the same as the surface of the conductive frame 6c.

The connection between the conductive frame 6c and the bare chip 6f is performed as follows, for example. First, a specified amount of the conductive adhesive 6g is arranged at a substantially center position of the contact facing surface 6ht, which is the top of the convex portion 6h of the conductive frame 6c. Next, the bare chip 6f is arranged at a position above the contact facing surface 6ht and not in contact with the conductive adhesive 6g in a posture in which the bottom surface 6fb faces the conductive frame 6c. Then, the conductive frame 6c and the bare chip 6f are connected by bringing the bare chip 6f and the convex portion 6h closer to each other and bringing the bare chip 6f into contact with the conductive adhesive 6g.

However, in any of the following cases, the conductive adhesive 6g may come into contact with the side surface of the bare chip 6f to cause a short circuit. That is, when the amount of the arranged conductive adhesive 6g is larger than the specified amount, when the distance between the bare chip 6f and the convex portion 6h is shorter than the specified distance, the conductive adhesive 6g is an abbreviation for the contact facing surface 6ht. For example, when it is arranged deviated from the center position. As a countermeasure against such a situation, in the present embodiment, the contact facing surface 6ht is formed into a regular octagonal shape.

(Shape of contact facing surface 6 ht)
FIG. 7A is a diagram showing the shape of the contact facing surface 6ht in the present embodiment, and FIG. 7B is a diagram showing the shape of the contact facing surface P of the comparative example. .. However, in FIG. 7, the bottom surface 6fb is shown by a broken line in order to show the positional relationship between the contact facing surface 6ht and the bottom surface 6fb, which is difficult to understand only in FIG. As described above, the contact facing surface 6ht has a regular octagonal shape. The bottom surface 6fb has a larger area than the contact facing surface 6ht, and the bare tip 6f is arranged so that the bottom surface 6fb covers the contact facing surface 6ht in a plan view. Comparative Example The facing surface P has a square shape, that is, a quadrangular shape, which is easy to create. Also in the comparative example, the bare chip 6f is arranged so that the bottom surface 6fb covers the facing surface P of the comparative example.

(Comparison of spread of 6 g of conductive adhesive)
8 and 9 are diagrams showing a comparison between Examples and Comparative Examples with respect to the spread of the conductive adhesive 6 g when the amount of the arranged conductive adhesive 6 g is too large. However, the example refers to the case where the contact facing surface 6ht shown in FIG. 7 (a) is used, and the comparative example refers to the case where the comparative example facing surface P shown in FIG. 7 (b) is used. Further, in all the figures of FIGS. 8 and 9, the hatching shows 6 g of the conductive adhesive. Further, in the examples and the comparative examples, the amount of 6 g of the conductive adhesive arranged is the same. Further, in FIGS. 8 and 9, four states are shown by naming them as the first stage to the fourth stage for convenience.

FIG. 8 is a plan view of the contact facing surface 6ht as viewed from above, and FIG. 9 is a cross-sectional view. The first to fourth stages of FIGS. 8 and 9 correspond to each other. Further, the bare chip 6f is shown in FIG. 9, but the bare chip 6f is not shown in FIG. In the present embodiment, the length of the conductive adhesive 6 g protruding outward from the contact facing surface 6 ht and the comparative example facing surface P is defined as the outflow length L. The longer the outflow length L, the higher the possibility that the conductive adhesive 6g will come into contact with the side surface of the bare chip 6f.

The outline of the first to fourth stages will be described. In the first stage, the bare chip 6f is not in contact with the conductive adhesive 6g, and in the second to fourth stages, the distance between the bare chip 6f and the convex portion 6h is gradually reduced. The fourth stage is the closest between the two. However, in FIGS. 8 and 9, the distance between the bare chip 6f and the convex portion 6h is constant, and it can be regarded as a comparison between the examples and the comparative examples when the amounts of the arranged conductive adhesives 6g are different. Each stage will be described below.

In the first stage, the bare chip 6f is not in contact with the conductive adhesive 6g in the first stage, and there is no difference in the state of the conductive adhesive 6g between the examples and the comparative examples. In the second stage, 6 g of the conductive adhesive is crushed and spread, but there is still no difference in the shape of the 6 g of the conductive adhesive. However, as shown in FIG. 8, in the embodiment, each of the eight sides of the contact facing surface 6ht is on the verge of contact with the conductive adhesive 6g, but in the comparative example, since the comparative example facing surface P is a quadrangle, each of the four sides is conductive. It is on the verge of contact with 6 g of the sex adhesive. Further, in the first stage and the second stage, the outflow length L is zero in both the examples and the comparative examples.

In the third stage, both the contact facing surface 6ht and the comparative example facing surface P are further crushed by the conductive adhesive 6g to come into contact with the contact facing surface 6ht and the side of the comparative example facing surface P, and are conductive from the contacted portion. 6 g of the sex adhesive flows out to the outside of the contact facing surface 6 ht and the comparative example facing surface P. At this time, 6 g of the conductive adhesive flows out from the eight sides in the example, but 6 g of the conductive adhesive flows out from the four sides in the comparative example. Since the amount of the conductive adhesive 6 g flowing out of the contact facing surface 6 ht and the comparative example facing surface P is substantially the same in the examples and the comparative examples, the amount of the conductive adhesive 6 g flowing out from one place is the example. Is half of the comparative example. Therefore, as shown in the third stage of FIGS. 8 and 9, the outflow length L of the examples is shorter than that of the comparative examples.

Then, as shown in the third stage of FIG. 9, in the embodiment, the conductive adhesive 6 g is contained inside the width of the bare chip 6f, but in the comparative example, the conductive adhesive 6 g extends to the outside of the width of the bare chip 6f. .. In FIG. 9, in order to clarify the difference, the conductive adhesive 6 g is shown to spread only in the horizontal direction shown in the drawing, but when the conductive adhesive 6 g spreads to the outside of the width of the bare chip 6f, it actually spreads. It also spreads in the vertical direction shown. That is, in the comparative example, there is a possibility that 6 g of the conductive adhesive may come into contact with the side surface of the facing surface P of the comparative example and short-circuit in the third stage.

In the final fourth step, the conductive adhesive 6 g is further crushed, and the outflow of the conductive adhesive 6 g to the outside of the contact facing surface 6ht and the comparative example facing surface P is further increased. However, as shown in FIG. 8, there is a strong tendency for the amount of outflow from the location where the outflow was started in the third stage to increase, and it is difficult for the outflow location to increase. Even if the number of outflow points increases, the relationship in which the number of outflow points is larger in the examples than in the comparative examples is maintained. Therefore, as shown in FIG. 9, in the fourth stage, the difference in the length of the conductive adhesive 6 g protruding from the bare chip 6f becomes remarkable between the example and the comparative example, and in the comparative example, the conductive adhesive 6 g faces the comparative example. The possibility of contacting the side surface of the surface P and causing a short circuit increases. In the fourth stage, there is a possibility of short-circuiting in the examples, but at least it is less likely than in the comparative examples.

According to the first embodiment described above, the following effects can be obtained.
(1) The igniter 6 includes a conductive frame 6c and a bare chip 6f fixed to the conductive frame 6c with a conductive adhesive 6g. The conductive frame 6c includes a base portion 6k and a convex portion 6h protruding from the base portion 6k toward the bare chip 6f. The contact facing surface 6ht, which is the surface of the convex portion 6h in contact with the bare chip 6f, has a regular octagonal shape, and 6 g of the conductive adhesive is applied to the contact facing surface 6ht.

In general, a bare chip has the advantage of being smaller and less costly than a packaged chip because there is no package, but there is a concern of short circuit. Since the igniter 6 has the above-described configuration, even if the amount of the conductive adhesive 6g arranged is too large, the conductive adhesive 6g protrudes from the contact facing surface 6ht in eight directions relatively shortly, and the conductive adhesive is adhered. There is a low risk that the agent 6g will come into contact with the side surface 6fs or the upper surface 6ft of the bare chip 6f to cause a short circuit. Further, if the comparative examples shown in FIGS. 8 and 9 are used, the outflow length L becomes relatively long, so the amount of the conductive adhesive 6 g to be arranged and the distance between the bare tip 6f and the convex portion 6h should be controlled. Must be done strictly. However, according to the present embodiment, since the outflow length L is relatively short, strict control as in the comparative example is not required, and efficient assembly is possible when the bare chip 6f is used.

(2) The base portion 6k is a groove formed in the conductive frame 6c. Therefore, it is possible to suppress the height of the contact facing surface 6ht, which is the top of the convex portion 6h, so that the height is aligned with the surface of the conductive frame 6c, for example. Therefore, the height of the conductive frame 6c when the bare chip 6f is mounted can be suppressed, and the igniter 6 can be miniaturized. Further, since the parts having a height that are plated in the manufacturing process of the igniter 6 are difficult to mask, the manufacturing process can be simplified by suppressing the height.

(3) The bare chip 6f is a rectangular parallelepiped, the surface of the bare chip 6f facing the conductive frame 6c is the bottom surface 6fb, and the side surface 6fs, which is the four surfaces in contact with the bottom surface 6fb, does not have an insulating layer. Since the contact facing surface 6ht of the igniter 6 is octagonal, the outflow length L is relatively short, and the conductive adhesive 6g is unlikely to come into contact with not only the upper surface 6ft of the bare chip 6f but also the side surface 6fs. Therefore, not only a bare chip having an insulating layer on the side surface 6fs but also a bare chip 6f having no insulating layer on the side surface 6fs can be used for the igniter 6, and various bare chips 6f can be used for the igniter 6.

(Modification example 1)
In the first embodiment described above, the contact facing surface 6ht was a regular octagon. However, the contact facing surface 6ht may be an octagon having unequal side lengths, or may be a pentagon or more. That is, the number of sides is not limited to 8, and may be 5 or more.

(Modification 2)
In the first embodiment described above, the contact facing surface 6ht was a regular octagon. However, the contact facing surface 6ht is preferably a circle, and more preferably a perfect circle.

FIG. 10 is a diagram showing the outer shape of the contact facing surface 6 ht in the modified example 2. As shown in FIG. 10, the contact facing surface 6ht in the modified example 2 is a perfect circle. Therefore, when 6 g of the conductive adhesive flows out of the contact facing surface 6 ht, it flows out from eight places in the first embodiment, but in this modified example, it flows out from the entire circumference of the contact facing surface 6 ht. Therefore, according to the configuration of the second modification, the outflow length L can be theoretically the shortest.

(Modification example 3)
In the first embodiment described above, the height of the convex portion 6h is the same as the surface of the conductive frame 6c. However, the convex portion 6h may protrude from the conductive frame 6c. That is, in this modification, the base portion 6k is the surface of the conductive frame 6c and does not have the groove 6j.

FIG. 11 is an external view of the convex portion 6h in the modified example 3. In this modification, the convex portion 6h protrudes from the conductive frame 6c.

-Second embodiment-
A second embodiment of the igniter according to the present invention will be described with reference to FIG. In the following description, the same components as those in the first embodiment are designated by the same reference numerals, and the differences will be mainly described. The points not particularly described are the same as those in the first embodiment. The present embodiment is different from the first embodiment mainly in that the relative posture relationship between the bare tip 6f and the convex portion 6h is taken into consideration.

FIG. 12 is a diagram showing the relationship between the contact facing surface 6ht of the convex portion 6h and the bottom surface 6fb of the bare chip 6f in the second embodiment. As shown in FIG. 12, the contact facing surface 6ht in the second embodiment has a shape in which the corners of a square are cut off instead of a regular octagon. That is, the contact facing surface 6 ht includes four long sides 6 htL and four short sides 6 htS. However, as shown in FIG. 12, when the distance from the center to the short side 6 htS is d1 and the distance from the center to the long side 6 htL is d2, there is a relationship of d1> d2. Further, the contact facing surface 6ht and the bottom surface 6fb are substantially similar figures, but the centers are aligned and tilted by 45 degrees. Therefore, if the distance from the short side 6 htS to the edge of the bottom surface 6 fb is m1 and the distance from the long side 6 htL to the edge of the bottom surface 6 fb is m2, there is a relationship of m1 <m2.

In the present embodiment, since there is a relationship of d1> d2, 6 g of the conductive adhesive flows out from the central portion of the long side 6 htL having a short distance from the center. The conductive adhesive 6 g flowing out from the central portion of the long side 6 htL does not have a risk of coming into contact with the side surface 6 fs until the outflow length L exceeds the distance m2. If 6 g of the conductive adhesive flows out from the short side 6 htS, there is a relatively high possibility of a short circuit because the distance m1 to the edge is short, but 6 g of the conductive adhesive flows out from the long side 6 htL which has a long distance to the edge. This reduces the possibility of a short circuit.

Each of the above-described embodiments and modifications may be combined. Although various embodiments and modifications have been described above, the present invention is not limited to these contents. Other aspects conceivable within the scope of the technical idea of the present invention are also included within the scope of the present invention.

6 ... Igniter 6d ... Electronic component 6h ... Convex part 6ht ... Contact facing surface

Claims (2)

An igniter having a conductive frame and a bare chip fixed to the conductive frame with a conductive adhesive.
The conductive frame is
The base and
It is provided with a convex portion protruding from the base portion toward the bare chip side.
The contact facing surface, which is the surface of the convex portion in contact with the bottom surface of the bare chip, is octagonal, and the conductive adhesive is applied to the contact facing surface.
The base portion is a groove formed in the conductive frame.
The contact facing surface includes four alternating long sides and four short sides.
The distance from the center of the contact facing surface to the short side is longer than the distance from the center of the contact facing surface to the long side.
It said distance from the short side to the edge of the bottom surface of the bare chip is shorter than the distance from the long sides to the edge of the bottom surface of the bare chip, igniter. In the igniter according to claim 1,
An igniter which is a rectangular parallelepiped and does not have an insulating layer on four side surfaces which are in contact with the bottom surface when the surface of the bare chip facing the conductive frame is the bottom surface.

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