JP2011155056A - Shielding structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a shield structure having improved heat dissipation efficiency, irrespective of applying a load on a solder section connecting an electronic component and a printed board, in a shielding structure which dissipates heat of electronic components inside a shielding case and which shields electromagnetically. <P>SOLUTION: A hole 6 for a fin and a fin pressure bar spring 7 are provided in the top surface of a shield case 1, and a fin base 2b of a radiation fin 2 is pressed with the fin pressure bar spring 7 so that the radiation fin 2 is brought into pressure contact with an electronic component 3; and a fin section 2a of the radiation fin 2 is exposed to the outside of the shield case 1 through the hole 6 for a fin. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a shield structure for electromagnetically shielding an electronic component such as an IC mounted on a printed board, and a shield structure for mounting a heat radiation fin for cooling the electronic component in a shield case.

  In an electronic component such as an IC mounted on a printed circuit board, for an electronic component in which heat generation is a problem, it is common to dissipate heat by providing a radiation fin. In addition, in wireless devices, etc., in order to block predetermined electronic components from electromagnetic noise received from the periphery of the device and electromagnetic noise generated by itself, or to reduce the influence on other components due to electromagnetic noise emitted by the predetermined electronic components, In many cases, a shield case is provided to cover the electronic component. Therefore, a shield structure that radiates and electromagnetically shields the electronic components in the shield case is required.

  As a method for fixing the radiating fin to the electronic component, a method using an adhesive is common. As a shield structure for heat dissipation and electromagnetic shielding of electronic parts, a mounting member having a screw hole is fixed to the electronic part with an adhesive, and a heat dissipation fin and a shield case are fixed to the mounting member with screws. (For example, refer to Patent Document 1).

  As another shield structure, a hole is provided on the side of the shield case, the radiating fin is supported by the radiating fin holding spring, the radiating fin is pressed against the electronic component, and the radiating fin holding spring is fixed by the hole on the side of the shielding case. (For example, refer to Patent Document 2).

Japanese Patent No. 2586389 JP-A-9-293980

  In a structure where the mounting member is fixed to the electronic component with an adhesive, and the radiation fin and shield case are fixed to the mounting member with screws, the mass of the metal radiation fin is reduced when vibration is applied to the electronic device during transportation. You will receive it with electronic components. For this reason, a load is applied to the solder portion connecting the electronic component and the printed circuit board, which causes cracks. As a result, problems such as a decrease in reliability and malfunction of the electronic device occur. In addition, fixing with an adhesive has a problem that workability is poor and assembly quality is likely to vary. Also in the heat dissipation performance, since there are many attachment members, heat conductive sheets, shield cases, and inclusions in the path for transferring the heat from the electronic component to the heat dissipation fin, there is a problem that the heat resistance increases and the heat dissipation efficiency is poor.

  On the other hand, in the structure in which the radiating fin is fixed by the radiating fin holding spring, the radiating fin is covered with the shield case. For this reason, the heat released from the radiating fins does not diffuse to the outside, and in the case of forced air cooling, the cooling air does not hit the radiating fins, so the cooling effect by the radiating fins is small and the heat radiating efficiency is poor. .

  The present invention was made in order to solve the above-described problems, and it is possible to obtain a shield structure in which no load is applied to a solder portion that connects an electronic component and a printed board even when vibration is applied during transportation or the like. Objective. Another object is to improve the heat dissipation efficiency of the shield structure.

  A shield structure according to the present invention includes a fin case having a fin hole and a fin holding spring, covering a electronic component mounted on a printed circuit board, and a heat dissipating fin having a fin portion and a fin base portion. The fin base portion is pressed by a holding spring so that the heat radiating fin is pressed against the electronic component, and the fin portion is exposed to the outside of the shield case from the fin hole.

  In the present invention, since the heat radiation fin is pressed against and fixed to the electronic component by the fin holding spring without using an adhesive, no load is applied to the solder portion even when vibration is applied. For this reason, the reliability of the electronic apparatus which employ | adopts this invention improves. Moreover, since the radiation fin is exposed to the outside of the shield case, the heat radiation efficiency can be increased.

It is an exploded view which shows the shield structure in Embodiment 1 of this invention. It is a perspective view which shows the shield structure in Embodiment 1 of this invention. It is sectional drawing which shows the shield structure in Embodiment 1 of this invention. It is an exploded view which shows the shield structure in Embodiment 2 of this invention. It is sectional drawing which shows the shield structure in Embodiment 2 of this invention. It is sectional drawing which shows the shield structure in Embodiment 2 of this invention. It is an exploded view which shows the shield structure in Embodiment 3 of this invention. It is an exploded view which shows the shield structure in Embodiment 3 of this invention.

  An embodiment of a shield structure according to the present invention will be described with reference to the drawings. In the following drawings, the same reference numerals indicate the same or corresponding configurations. In addition, this invention is not limited to each embodiment shown below.

Embodiment 1 FIG.
FIG. 1 is an exploded view showing a shield structure according to the first embodiment of the present invention, and FIG. 2 is a perspective view showing the shield structure according to the first embodiment of the present invention. A shield structure that radiates heat and electromagnetically shields the electronic component 3 mounted on the printed circuit board 4 will be described. On the top surface of the shield case 1, a fin hole 6 for bringing the fin portion 2 a of the radiation fin 2 out of the shield case 1 and a fin holding spring 7 for fixing the radiation fin 2 are formed. . The fin holding spring 7 is provided adjacent to the fin hole 6. A metal shield base 5 is soldered and fixed to the printed circuit board 4 so as to surround the electronic component 3 and its peripheral circuits, and is electrically connected to the ground of the printed circuit board 4. A fixing hole 9 for fixing the shield case 1 is provided on the side surface of the shield base portion 5. A protrusion 8 is provided on the side surface of the shield case 1 so as to face the fixing hole 9. The radiating fin 2 is fixed to the electronic component 3 by the fin holding spring 7, and the fin portion 2 a of the radiating fin 2 is exposed to the outside of the shield case 1 through the fin hole 6 as shown in FIG. 2.

  FIG. 3 is a cross-sectional view showing the shield structure in the first embodiment of the present invention. The shield case 1 is made of a springy metal, and the top and side surfaces are formed by bending a single sheet metal. The side surface of the shield case 1 is bent so as to incline toward the inside of the shield case toward the opening surface (the surface facing the top surface, the lower side in the figure). Since this side surface spreads with a spring property, the shield case 1 can be fitted to the shield base portion 5 so as to cover the shield base portion 5. By fitting the protruding portion 8 formed on the side surface of the shield case 1 and protruding inward into the fixing hole 9 of the shield base portion 5, the shield case 1 is not easily detached. Since all four sides of the shield case 1 are bent inward, the shield case 1 is pressed against the shield base portion 5 from the outside to make electrical contact, and electromagnetic shielding is maintained. .

  The heat radiating fin 2 has a shape in which the base portion 2b projects to the periphery rather than the fin portion 2a. A fin holding spring 7 is provided along the opposite side of the square fin hole 6 on the top surface of the shield case 1. The fin pressing spring 7 is inclined toward the inside of the shield case 1, presses the base portion 2 b of the radiating fin 2, presses the radiating fin 2 against the electronic component 3, and fixes the radiating fin 2.

  Since the shield structure in the first embodiment is fixed by pressing the heat dissipating fin 2 to the electronic component 3 by the fin holding spring 7 without using an adhesive, even when vibration is applied during transportation or the like, the printed structure and the electronic component 3 are printed. No load is applied to the solder portion connecting the substrate 4. For this reason, a crack does not generate | occur | produce in a solder part and the reliability of the electronic device which employ | adopts this shield structure improves. Further, since the heat dissipating fins 2 are fixed by the fin pressing springs 7 without using an adhesive, there is an effect that the assemblability is good and the disassembly / repair is facilitated.

  Further, in the shield structure according to the first embodiment, since the fin portion 2a of the radiating fin 2 is exposed to the outside of the shield case 1, heat is not trapped in the shield case 1 and is generated from the electronic component 3. Heat can be discharged to the outside of the shield case 1 to improve heat dissipation efficiency. In addition, in the case of forced air cooling, since the cooling air directly hits the fin portion 2a, the heat radiation efficiency can be further increased.

Embodiment 2. FIG.
In the first embodiment, the shield case 1 is fixed to the shield base 5, but may be directly fixed to the printed circuit board 4. FIG. 4 is an exploded view showing the shield structure in the second embodiment of the present invention, and FIG. 5 is a cross-sectional view showing the shield structure in the second embodiment of the present invention. The side surface of the shield case 1 is inclined inward toward the opening surface (the surface facing the top surface). Further, a claw portion 10 that is bent inward is formed at the opening end portion (end portion on the opening surface side) of the side surface of the shield case 1. The shield case 1 can be directly fixed to the printed circuit board 4 by inserting the claw portion 10 into the shield fixing hole 11 of the printed circuit board 4 and locking it. For this reason, a shield base part becomes unnecessary, a number of parts can be reduced and an assembly becomes easy.
FIG. 6 is a cross-sectional view showing a shield structure according to Embodiment 2 of the present invention. In FIG. 5, the side surface of the shield case 1 is formed so as to be inclined inward toward the opening surface, but may be inclined outward toward the opening surface as shown in FIG. In this case, the claw portion 10 is formed by being bent outside the shield case 1. When the side surface of the shield case 1 is inclined outward, the claw portion 10 can be inserted into and removed from the shield fixing hole 11 by pushing the side surface of the shield case 1 inward, so that workability is further improved.
In the shield structure according to the second embodiment, since the shield case 1 is directly fixed to the printed circuit board 4, the shield base portion is not necessary, the number of parts can be reduced, and the assemblability is improved. Further, by inclining the side surface of the shield case 1 to the outside, it is easy to insert into and remove from the printed circuit board 4 and workability is improved.

Embodiment 3 FIG.
In the first and second embodiments, the fin pressing spring 7 is provided only on the opposite side (two sides) of the fin hole 6, but may be provided on the four sides around the fin hole 6. In the third embodiment, a case will be described in which fin holding springs 7 are provided on the four sides of the fin hole 6 with respect to the shield structure of the second embodiment. FIG. 7 is an exploded view showing a shield structure according to Embodiment 3 of the present invention. The fin hole 6 of the shield case 1 is rectangular, but fin holding springs 7 are provided on all four sides (both opposite sides). The fin holding spring 7 is structured to be inclined from the four sides around the fin hole 6 to the inside of the shield case 1. Since the fin holding springs 7 are in contact with the radiating fins 2 not only on the two sides of the fin hole 6 but on all four sides, the shielding performance is improved.
FIG. 8 is an exploded view showing a shield structure according to Embodiment 3 of the present invention. The fin presser spring 7 has a shape with a large number of cuts. With this structure, since the radiation fin 2 and the fin holding spring 7 are in contact with each other by a large number of springs, it is possible to shield more reliably.
In the shield structure according to the third embodiment, the fin holding springs 7 are provided on the four sides around the fin hole 6, so that the shielding performance is improved. Furthermore, by making a large number of cuts in the fin pressing spring 7, the number of contact points between the heat radiating fins 2 and the fin pressing spring 7 increases, so that the shielding performance is further improved.

DESCRIPTION OF SYMBOLS 1 Shield case 2 Radiation fin 3 Electronic component 4 Printed circuit board 5 Shield base part 6 Fin hole 7 Fin pressing spring 8 Protrusion part 9 Fixing hole 10 Claw part 11 Shield fixing hole

Claims (6)

A shield case having a fin hole and a fin holding spring and covering an electronic component mounted on a printed circuit board;
A radiation fin having a fin portion and a fin base portion;
With
Pressing the fin base portion with the fin pressing spring to press the heat radiating fin against the electronic component,
A shield structure in which the fin portion is exposed to the outside of the shield case from the fin hole. Mounted on the printed circuit board, comprising a shield base portion surrounding the electronic component,
The shield base portion has a fixing hole on a side surface,
On the side surface of the shield case, a protrusion is provided at a position facing the fixing hole,
The shield structure according to claim 1, wherein the shield case is fixed to the shield base portion by fitting the protrusion into the fixing hole. The side surface of the shield case is inclined inward toward the opening surface, and an opening end portion of the side surface is provided with a claw portion bent inward,
The shield structure according to claim 1, wherein the claw portion is locked in a shield fixing hole provided in the printed board to fix the shield case to the printed board. The side surface of the shield case is inclined outward toward the opening surface, and an opening end portion of the side surface is provided with a claw portion bent outward.
The shield structure according to claim 1, wherein the claw portion is locked in a shield fixing hole provided in the printed board to fix the shield case to the printed board. The shape of the fin hole is a square,
The shield structure according to any one of claims 1 to 4, wherein the fin holding spring is provided on at least one side of the fin hole.   The shield structure according to any one of claims 1 to 5, wherein the fin pressing spring has a large number of cuts.

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