JPS6018156B2 - Electrical equipment case and its manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention specifies an electrical equipment case in which a metal plate is embedded, and a method for manufacturing the same is a combined invention.

Recently, small household products such as electric razors have become smaller and thinner, but the reliability of electronic components has been affected by the internal heat generation of electronic circuits such as densely packed control circuits and chargers, and motors. There was a problem that the temperature of the case decreased and the temperature of the case rose, causing a sense of anxiety to the user.

Therefore, it is necessary to improve the heat dissipation of the product, and various attempts have been made to date. Figure 1 shows the case of a conventional electric shaver.The case body 1', which is constructed by combining two halves 24' (only one shown in Figure 1), contains electronic circuits, motors, and drivers. (None of the parts are shown). In this conventional example, an insulating plate 22 such as a pressboard is sandwiched between a metal plate 16' such as aluminum and an electronic circuit on the inner surface of the semicircular body 24'.
However, in the above conventional example, as shown in FIG. 1, ribs 23 and the like for fixing electronic circuits, motors, batteries, switches, etc. protrude from the inner surface of the case body 1', and the metal plate 16' It is necessary to provide notches 29 in the insulating plate 22 to avoid these ribs 23, resulting in a disadvantage that the heat dissipation area becomes small and heat dissipation is poor. On the other hand, to install the metal plate I6' and the insulating plate 22 on the inner surface of the case body 1', adhesive is used to attach the metal plate I6' and the insulating plate 22, which have complex shapes. cannot be glued,
The drawback was that the heat dissipation effect varied depending on the product. In view of the above-mentioned points, the present invention embeds a metal plate for heat dissipation in the case, thereby eliminating the step of assembling the metal plate, and achieving uniform and effective heat dissipation of the product. It is an object of the specific invention to provide an electrical equipment case that can reliably hold a metal plate inserted therein, and an object of the combined invention is to provide a method for manufacturing the same.

The present invention will be described in detail based on an example in which the present invention is used in a thin electric shaver.

That is, the case body 1 is formed into a thin box shape by the front and rear half bodies 24 (only one is shown), and each half body 24,
Reference numeral 25 is made of synthetic resin and is formed into a shape in which a peripheral wall 27 extends from the periphery of a rectangular face plate, so that the peripheral walls 27 can be butted against each other. Note that 3 is a rib for fixing the motor 12 and electronic components. In the case body 1 of the present invention, as shown in FIGS. 2a and 2b, a metal plate 16 made of a thermally conductive material such as aluminum and having a plurality of through holes 15 is provided over almost the entire housing position of the motor and charging part. It is buried. That is, as shown in FIG. 3, the case body 1 consists of an inner layer 14 made of electrically insulating synthetic resin, a thermally conductive metal plate 16, and a surface layer 13 made of synthetic resin forming the exterior. It has an approximately three-layer structure. Below, the case body 1 as described above
The manufacturing method will be described based on FIGS. 4 to 6.

However, although the same effect can be achieved even if the configuration is as shown in parentheses in the claims of the present application, the explanation thereof will be omitted in this embodiment. In FIG. 4, 17 is a convex movable mold, and this movable mold 17 and a concave fixed mold 20
and form a cavity 18. The movable mold 17 is provided with a plurality of pins 19 that can freely protrude into the cavity 18. These pins 19 can be restrained in the protruding state, and are housed in the movable mold 17 so that the end surfaces of the pins 19 and the cavity When the surface 18 becomes flush with the surface 18, it is locked by an appropriate means. A metal plate 16 made of aluminum and having a plurality of through holes 15 and coated with adhesive on the surface is remounted on the cavity 18 surface of the fixed mold 20, so that the end face of the pin 19 protruding into the cavity 18 is All the through holes 15 are closed and the pin 19 is restrained, and the end face of the pin 19 and the fixed mold 20 are closed.
The metal plate 16 is held and fixed between the cavity 18 surface and the cavity 18 surface. Needless to say, the outer diameter of the pin 19 is set larger than the diameter of the through hole 15. In this state, a molten synthetic resin serving as an insulating material is injected into the cavity 18, but since the metal plate 16 is fixed with a pin 19, it will not move due to the injection flow. The synthetic resin is then cured to form the inner surface layer 14 of the case body 1 on one side of the metal plate 16. Then, after forming the mold, a cavity 31 with a large volume is made as shown in FIG. Form and inject the molten plastic again. At this time, if the restraint state of the pin 19 is released, the pin 19 is housed in the movable mold 17 due to the resin pressure, and the pin 19 is moved into the cavity 31.
The surface and the end surface of the pin 19 are locked in a flush state. Therefore, the molten synthetic resin fills all the through holes 15 and hardens to form the surface layer 13. As a result, the surface layer 13 is filled into the through hole 15, and a golden portion 9 larger than the diameter of the through hole 15 is formed by the inner layer 14. Therefore, as shown in FIG. 6, the metal plate 16 can form a surface layer 13 completely surrounded by resin, increasing the mechanical bonding force between the metal plate 16, the inner layer 14 made of synthetic resin, and the surface layer 13. In addition, the layers 13 and 14 are firmly bonded together by the chemical bonding force of the adhesive applied to the metal plate 16, thereby improving the strength of the case body 1. Therefore, the wall thickness of the case can be made thinner than that of a conventional case using a single synthetic resin. Furthermore, by using a synthetic resin material different from the surface layer 13 for the inner layer 14, for example, a synthetic resin material with cushioning properties, it is possible to provide a cushioning effect for electronic components, motors, batteries, etc. built into the electric shaver, and to absorb sound. By using the anti-vibration structure, it is possible to absorb noise and vibration during rotation of the motor and blade. Furthermore, by embedding the metal plate 16 in the peripheral wall 27 of the case body 1 as shown in FIG.
The heat dissipation area can be expanded and the heat dissipation effect can be improved.
The mechanical strength of the case body 1 can also be increased.

Thus, in the specific invention, since the metal plate having a plurality of through holes is buried between the surface layer and the inner surface layer of the synthetic resin case body, the heat sink can be attached at the same time as the case body is assembled. This simplifies the installation of metal plates for heat dissipation, and the heat dissipation area does not become smaller due to ribs as in the past, increasing the heat dissipation effect. It does not reduce the reliability of the product or cause users to feel uneasy, and there is no need to glue metal plates or insulating plates with complicated shapes, so the heat dissipation effect is uniform, and the heat dissipation by the product is improved. This eliminates the variation in

Furthermore, in a synthetic resin case body consisting of two layers with a front layer and a back layer formed on both sides of a metal plate, either the front layer or the inner layer is passed through a hole in the metal plate to form the inner layer side or the front side. Since the layer side is polymerized around the outer periphery of the hole to form a metal part larger than the diameter of the hole, the front and back surfaces of the case body can be made of different materials, and the surface layer or back layer can be made of different materials. This has the effect of ensuring that the metal plate can be held securely. On the other hand, in the combined invention, a metal plate having a plurality of through holes is held between a plurality of protruding pin end surfaces provided in a cavity of a movable mold and a cavity surface of a fixed mold, The molten synthetic resin is injected with the through holes of the metal plate closed at the end of each pin to form the inner surface layer of the case body on one side of the metal plate. After opening the mold, the fixed mold is replaced and the molten synthetic resin is poured again. Since the surface layer of the case body is formed by injecting resin and making the cavity surface of the movable mold and the pin end surface flush with each other, the case body can be formed so that the metal plate is completely surrounded by the resin. , the mechanical bonding force between the surface layer and the inner layer becomes stronger, and the case body is stronger in strength and can be made thinner than the conventional single synthetic resin case body. Furthermore, since the diameter of the multiple pins freely protruding from the cavity surface is larger than the diameter of the through hole, the metal plate can be held securely by the pins during the initial injection of resin, and the insert position of the metal plate can be prevented from shifting. When the resin is next injected, the synthetic resin that forms the surface layer (inner layer) filled in the through hole becomes larger in diameter on the other side of the hole, and the metal plate is mechanically held by the surface layer (inner layer). This has the effect of preventing peeling or lifting. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded perspective view of essential parts of a subordinate example, FIG. 2 a is a front view of essential parts showing an embodiment of the present invention, and FIG. cross section,
Figure 3 is a partially enlarged sectional view of the same as above, Figures 4 and 5 are explanatory views showing the manufacturing method of the same, Figure 6 is a partially enlarged sectional view of the same, and Figure 7 is an application of the same. 1 is a partially enlarged sectional view of the example, 1 is a case body, 9 is a flange, 13 is a surface layer, 14 is an inner layer, 15 is a through hole, 16 is a metal plate, 17 is a movable mold, and 18 is a Cavity 19 is a pin, 20G fixed mold.

Figure 2 Figure 3 Figure 4 Figure 1 Figure 5 Figure 6 Figure 7

Claims (1)

[Scope of Claims] 1. In an electrical equipment case in which a metal plate having a plurality of through holes is embedded between the surface layer and the inner layer of a synthetic resin case body, either the surface layer or the inner layer is made of a metal plate. An electrical equipment case characterized in that a flange portion having a diameter larger than the through hole is formed by passing through the through hole and overlapping the outer periphery of the through hole on the inner layer side or the surface layer side. 2. The electrical equipment case according to claim 1, wherein either the surface layer or the inner layer is made of a synthetic resin material having cushioning properties. 3 A metal plate having a plurality of through holes is held between the end face of a plurality of pins that are freely protruded from the cavity surface of a movable (fixed) mold and the cavity surface of a fixed (movable) mold, The inner (front) surface layer of the case body is formed on one side of the metal plate into which molten synthetic resin is injected, with the through holes in the metal plate being closed with the end faces of the protruding pins that have a diameter larger than the diameter of the holes. After opening the mold, replace the fixed (movable) mold and inject the molten synthetic resin again, and then retract each pin until the cavity surface of the movable (fixed) mold and the pin end surface are flush with each other. A method for manufacturing an electrical equipment case, characterized in that the front (inner) surface layer of the case body is formed using the following methods.