JP2590601B2 - Electronic ignition device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an electronic ignition device for an internal combustion engine mounted on an automobile or the like.

2. Description of the Related Art Conventionally, some internal combustion engines mounted on automobiles and the like employ an electronic ignition device.

In the conventional electronic ignition device, as shown in FIG. 6, electronic components such as a power transistor b, a semiconductor integrated circuit c, and a chip capacitor h are provided on a heat sink a via an insulating plate d and a printed board e. In addition, a heat radiating balancer f is provided above the heat radiating plate a, and the heat radiating plate a and the heat radiating balancer f are integrally molded with a package g made of resin together with electronic components and the like.

However, in the above-described conventional electronic ignition device, the bottom surface of the heat sink a and the upper surface of the heat balancer f are exposed from the surface of the package g. When used in an environment, a gap is generated at the boundary between the heat radiating plate a or the heat radiating balancer f and the package g due to a difference in expansion coefficient between the resin and the metal. Is oxidized due to fouling gas, and the solder connection deteriorates early, causing a problem such as a decrease in the function of the electronic igniter or a failure.

SUMMARY OF THE INVENTION The present invention has been made in order to improve the above-described problem, and has as its object to provide an electronic ignition device for an internal combustion engine having improved reliability by preventing oxidation of a solder connection portion.

Means for Solving the Problems In order to achieve the above object, the present invention fixes an electronic component or an external electrode and a printed circuit board on a heat radiating plate via a solder connecting portion, and furthermore, fixes the entire circumference of the heat radiating plate. Is integrally molded by a resin package.

Effect of the Invention With the above configuration, the present invention does not allow the fouling gas to enter the gap even if a gap is generated between the heat sink and the package due to the difference in the coefficient of thermal expansion between the heat sink and the package. Can be prevented from being oxidized at the solder connection portion for connecting the semiconductor device, thereby preventing the device from malfunctioning and improving the reliability.

Embodiment An embodiment of the present invention will be described in detail with reference to the drawings shown in FIG. 1 and FIG.

In the figure, 1 is a heat radiating plate made of a metal plate, 2 is a resin package, 3 is a semiconductor integrated circuit, 4 is a chip capacitor, 5 is a power transistor, and 6 is an external electrode.

A printed board 8 on which the semiconductor integrated circuit 3 and the chip capacitor 4 are mounted is fixed on the heat sink 1, and a power transistor 5 mounted on the heat spreader 7 adjacent to the printed board 8 is connected to an insulating plate 9. Has been fixed through.

One end of each of the plurality of external electrodes 6 is connected to the printed board 8 and the heat spreader 7, and the other end of each of the external electrodes 6 protrudes outside the package 2. In addition, electronic components and the like are molded in the package 2 by transfer molding.

Note that the bottom surface of the heat sink 1 is positioned so as to be on the surface side of the package 2 so that the heat dissipation effect of the heat sink 1 is not hindered, and the bottom surface of the heat sink 1 is not exposed from the surface of the package 2. The package 2 is molded.

Although the above embodiment is an example of an electronic ignition device having no heat radiation balance 10, in the case of an electronic ignition device provided with a heat radiation balancer 10, as shown in FIG.
The package 2 is molded so that the upper surface of the package 10 is not exposed from the surface of the package 2. In this case, the heat radiation of the heat-dissipating balancer 10 has the effect of equalizing the shrinkage strain of the package 2.

Further, as shown in FIG. 4, the printed substrate 8 provided with the electronic components and the package-molded power transistor 5a may be fixed on the heat sink 1, and these may be integrally molded by the package 2. In addition, as shown in FIG. 5, the inner and outer peripheries of the radiator plate 1 and the radiator balancer 10 may be molded by the package 2 in a state where the openings of the radiator plate 1 and the radiator balancer 10 are fitted to each other. .

Effect of the Invention As described in detail above, the present invention fixes a package between an electronic component or an external electrode and a printed board on a heat sink via a solder connection portion, and forms a package around the entire circumference of the heat sink using a resin. Since the mold is integrated into one, the difference in the coefficient of thermal expansion between the radiator plate and the package prevents contamination gas from entering the gap even if a gap occurs between the radiator plate and the package. Oxidation of the solder connection portion for connecting the substrate and the like can be prevented, and therefore, failure of the device can be prevented and reliability can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an electronic ignition device for an internal combustion engine according to an embodiment of the present invention, FIG. 2 is a perspective view of the same, and FIGS.
FIG. 6 is an explanatory diagram showing an electronic ignition device for an internal combustion engine according to another embodiment of the present invention, and FIG. 6 is an explanatory diagram showing a conventional electronic ignition device. 1 heat sink 2, package 3 semiconductor integrated circuit 5, 5a power transistor 6, external electrode 6,
8 ... printed circuit board, 10 ... heat dissipation balancer.

Claims (3)

(57) [Claims] An electronic component for controlling electronic ignition of an internal combustion engine and a printed board on which external electrodes are fixed via a solder connection portion are fixed on a heat radiating plate made of a metal plate.
An electronic igniter characterized by being integrally molded by transfer molding with a package made of resin so as to cover the entire outer periphery of the external electrode, the printed board and the heat sink. 2. The electronic ignition device according to claim 1, wherein the package is integrally molded with the package so as to cover the entire outer periphery of the heat radiation balancer provided to face the printed circuit board mounting surface of the heat radiation plate. 3. An inner and outer periphery of the heat radiating plate and the heat radiating balancer in a state where the opening of the heat radiating plate and the opening of the heat radiating balancer provided to face the printed circuit board mounting surface of the heat radiating plate are fitted to each other. The electronic ignition device according to claim 1, wherein the electronic ignition device is integrally molded with the package.