JPH0747912Y2 - Metal board case mounting structure - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a case mounting structure of a metal substrate for assembling an end portion of a metal substrate on which an electric circuit is mounted on a supporting end portion of a frame body made of synthetic resin,
In particular, the present invention relates to a case mounting structure for a metal substrate that improves the withstand voltage between the metal substrate and an electric circuit.

[0002]

2. Description of the Related Art Such a metal board case mounting structure is applied to, for example, a switching power supply device.
An example of a conventional case mounting structure of a metal substrate is shown in FIGS.
To explain together, reference numeral 1 is a metal substrate having a function as a heat dissipation plate, and an insulating layer 2 is coated on the surface thereof.
A conductive pattern for wiring an electric circuit is laminated on the side surface of the insulating layer 2 opposite to the metal substrate 1. Further, various electric parts are connected to the conductive pattern by soldering or the like to form the electric circuit. ing. In addition, a plurality of recesses 3 are formed at predetermined intervals at the end of the metal substrate 1.

Reference numeral 4 denotes a frame body made of an insulating synthetic resin. A frame-like step portion 6 is formed inside the side end 5, and
A plurality of engaging claws 7 facing the step portion 6 are formed at intervals equal to the arrangement intervals of the plurality of recesses 3. Then, the recess 3 formed on the back surface side of the metal substrate 1 and the engaging claw 7 are aligned with each other, and the end portion of the metal substrate 1 is fitted between the step 6 and the engaging claw 6. The structure is such that the metal substrate 1 and the frame body 4 are integrally combined in a state of being meshed with each other.

[0004]

However, in such a conventional case mounting structure of a metal substrate, as shown in FIG.
As shown in the partially enlarged view of FIG. 3, the side end portion 1a of the metal substrate is in a state in which it is not insulated by the insulating layer 2 or the like, that is, it is in an exposed state as it is cut. There is a problem that the dielectric strength between the side end 1a and the side end 1a becomes low.

As a result, for example, safety standards UL-195
0 to 1.5 kV to 3 kV for this part
If the insulation withstand voltage is to be secured, the distance W from the edge of the side end 1a to the conductive pattern of the electric circuit is 3 mm to 6 m.
It is necessary to open it, and the range for forming an electric circuit is limited, and conversely, since a large metal substrate is used to secure this distance W, the size of the entire device is increased. was there.

The present invention has been made in view of the above conventional problems, and an object of the present invention is to provide a case mounting structure for a metal substrate capable of improving the withstand voltage at the side end portion of the metal substrate. To do.

[0007]

In order to achieve such an object, the present invention provides a metal substrate in which an end portion of a metal substrate on which an electric circuit is mounted is assembled to a supporting end portion of a frame body made of synthetic resin. The case mounting structure of is targeted. Then, a protrusion that forms a constant gap between the end of the metal substrate and the support end of the frame is formed on the frame, and an adhesive having an insulating property is injected into the gap, thereby forming the metal. The substrate and the frame member are fixed to each other.

Further, the gap formed by the projections is set to allow the adhesive injected into the gap to enter with surface tension.

[0009]

According to the case mounting structure of the metal substrate having such a configuration, the insulating adhesive is filled in the gap between the end of the metal substrate and the supporting end of the frame, and the insulating adhesive is used. Since the side end of the metal substrate is covered with insulation, the withstand voltage at the side end of the metal substrate can be improved.

Further, the gap formed by the projections is
When the adhesive is injected into the gap, the gap can be easily filled with the surface tension so that the adhesive can be easily filled in the gap, and mechanization for automatic assembly is intended. Has an effect on.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows the structure when applied to, for example, a switching power supply device. In FIG. 1, reference numeral 8 is a metal substrate having a function as a heat sink, and an insulating layer 9 is coated on the surface thereof. A conductive pattern for wiring an electric circuit is laminated on a side surface of the insulating layer 9 opposite to the metal substrate 8,
Further, an electric circuit is configured by connecting various electric parts to the conductive pattern by soldering or the like.

Reference numeral 10 denotes a frame body made of an insulating synthetic resin, in which a groove-shaped support step portion 12 is formed inside a side end 11 thereof, and a predetermined inner surface of the support step portion 12 is provided. A plurality of protrusions 13 and 14 having a protruding length are formed at predetermined intervals. In the figure, the projection 13 is formed on the vertical inner surface of the support step portion 12, and the projection 14 is formed on the horizontal inner surface.

Then, the end portion of the metal substrate 8 is supported by the supporting step portion 12.
In combination, the gap formed between the inner surface of the support step portion 12 and the end portion of the metal substrate 8 by the projections 13 and 14 is filled with an insulating adhesive such as epoxy resin and solidified, thereby The substrate 8 and the frame body 10 are assembled together. Therefore, as partially shown in FIG. 2, the metal substrate 8 and the frame body 10 are assembled to each other via the adhesive 15 filled in this way.

In this embodiment, since the protrusion length of the protrusions 13 and 14 is designed to be about 0.3 mm, the adhesive material 15 shown in FIG. 2 has an adhesive property of about 0.3 mm due to the capillary phenomenon. Easily penetrates into the gap and even if the side surface 8a of the metal substrate 8 has an uneven cut surface, it enters the concave portion and also covers the convex portion, so that the side edge 8a is sealed and covered. Is filled.

As a result, the side end portion 8a of the metal substrate 8 is not covered with the insulating layer 9 for forming an electric circuit, but is substantially covered with the adhesive material 15. Generation of a discharge path between the end portion 8a and the electric circuit can be prevented, and the withstand voltage can be improved. Incidentally, according to this example, a withstand voltage of about 7 kV was obtained.

Due to the above capillary phenomenon, auxiliary means such as injecting the adhesive material 15 under pressure into the gap is unnecessary,
Further, when the gap is set to the above-mentioned gap, the adhesive 15 does not have the problem of liquid dripping from the gap due to the surface tension based on its adhesiveness, and the assembling work can be improved. effective.

[0017]

As described above, according to the case mounting structure of the metal substrate of the present invention, the protrusion formed on the supporting end portion of the frame body provides a space between the end portion of the metal substrate and the supporting end portion of the frame body. The gap formed is filled with an insulating adhesive, and the insulating adhesive covers the side end of the metal substrate.
The withstand voltage at the side edge of the metal substrate can be improved.

Further, since the withstand voltage is improved, it is not necessary to previously provide a space for securing the withstand voltage on the metal substrate as in the conventional case, and the downsizing of the metal substrate and the entire apparatus can be realized. . Further, by setting the gap formed by the protrusions such that the gap enters when the adhesive is injected into the gap, the adhesive can be easily filled in the gap, It is effective when mechanizing for automatic assembly.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing a partially broken structure of an embodiment of the present invention.

FIG. 2 is an exploded perspective view showing the structure of FIG. 1 partially broken.

FIG. 3 is an exploded perspective view showing a main part of a conventional metal board case mounting structure.

FIG. 4 is a partial perspective view showing the structure of the metal board for explaining the problems of the conventional case mounting structure of the metal board.

[Explanation of symbols]

 8; Metal substrate 9; Insulating layer 10; Frame body 11; Side end portion 12; Support step portion 13, 14; Protrusion 15; Adhesive material

Claims (2)

[Scope of utility model registration request] 1. An end portion of a metal substrate on which an electric circuit is mounted,
In a case mounting structure of a metal substrate assembled to a supporting end portion of a frame body formed of a synthetic resin, a protrusion for forming a constant gap between the end portion of the metal substrate and the supporting end portion of the frame body is provided in the frame body. A case mounting structure for a metal substrate, wherein the metal substrate and the frame are fixed to each other by injecting an insulating adhesive into the gap. 2. The gap formed by the protrusion is a gap that allows the adhesive injected into the gap to enter with a capillary phenomenon based on its adhesiveness. Metal board case mounting structure.