JPH1098288A - Electronic equipment case, heat, sink, and electronic equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrences of such problems as the thermal deformation, etc., of the peripheral sections of bosses of the case of electronic equipment used for fixing a circuit board, etc., to cases caused by the heat transfer from a heat generating source, such as the CPU, etc., on the circuit board. SOLUTION: Through-holes 20 for radiating heat are formed around the tapped hole 21, for tightening a screw 12 of a boss 16 protruded from a lower case 3 to which a circuit board 8 is fixed with screws and vent holes 22 respectively communicating with the holes 20 of the boss 16, are formed around a screwing hole 81 of the substrate 8 for passing the screw 12. Therefore, the occurrence of such problem as the thermal deformation, etc., in the surrounding area of the boss 16 of the lower case 3 caused by the heat accumulated in the boss 16 can be prevented, because the heat can be radiated effectively from the boss 16 through the holes 20 and 22.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic device such as a personal computer or a word processor, a case thereof, and a heat radiating structure of a heat radiating plate used for radiating a heat source such as a CPU provided in the electronic device. .

[0002]

2. Description of the Related Art FIGS.
2 will be described.

FIG. 11 is a perspective view of a laptop type word processor as an example of electronic equipment. FIG.
A printer 6 (see FIG. 12) as an output means is built in a rear portion of a main body case composed of an upper case 2 and a lower case 3, and a keyboard 10 as an input means is provided in a front portion of the main body case. When the display case 1 holding the liquid crystal display 4 as a means is not used, the keyboard 10 is folded down so as to cover it, and when used, the display case 1 stands on the main body case.

FIG. 12 shows a cross-sectional view thereof. Here, a shield plate 9 is placed on the bottom of the lower case 3, and a CP is placed thereon.
The circuit board 8 on which U25 is mounted is fixed to the screw boss 16 projecting from the lower case 3 with the screw 12, and the keyboard 10 is further fixed to the boss 16 'with the screw 12' above. Finally, the upper case 2 is covered. In order to prevent the temperature of the CPU 25 as a heat source from rising, the fan 5 is provided or the heat sink 11 is connected to the CPU 2.
5 or a heat sink 11
A larger plate-like heat radiating plate (not shown) is provided so as to be in contact with the upper surface of the CPU 25, and is fixed to the boss 16 together with the substrate 8 with the screw 12.

[0005]

There has been a remarkable improvement in CPU speed in recent years, and accordingly, the heat generated by the CPU itself tends to increase. However, providing a fan only for the heat generation of the CPU, which is about 80 degrees, has disadvantages such as cost increase and noise. Therefore, natural air cooling by the CPU element itself is generally used. Is also improving.

As a means of natural air cooling, there is a method of bonding and fixing a heat sink to the CPU as described above. However, in this case, it takes time and effort to dry the adhesive and to position the heat sink, thereby lowering productivity. With concern,
In recent years, downsizing of electronic devices has progressed, and in many cases, a height sufficient for attaching a heat sink cannot be secured.

In the case of natural air cooling using only the element itself, the heat generated from the CPU is conducted to the board fixing screw via the circuit board and air, and then to the screw boss of the lower case via the screw. The thermal deformation of the periphery of the boss due to heat storage (The thermal deformation temperature of the VO grade ABS member is 70
(Approximately -80 degrees), which may cause loosening of the screws and partial deformation of the lower case.

Further, when the heat radiation effect is insufficient with natural air cooling and a separate heat radiation plate is used, the heat radiation plate is fixed by screwing the boss of the lower case as described above. There is concern about the occurrence of thermal deformation around the boss.

SUMMARY OF THE INVENTION An object of the present invention is to provide a simple and inexpensive electronic device capable of solving the above-mentioned disadvantages, a heat radiating structure of the case, and a heat radiating plate structure.

[0010]

According to the present invention, there is provided, in accordance with the present invention, a screwing portion (for example, an inwardly projecting portion) for screwing a predetermined member (for example, a circuit board or a heat sink). In the electronic device case having the boss, a structure is used in which a through hole for heat dissipation by air cooling is formed around a screw hole for tightening the screw of the screw fixing portion.

[0011] Further, an insert member formed with the screw-down portion protruding inward as a boss and having a screw hole for tightening a screw is embedded in the center of the boss, and one end of the insert member is provided. Is exposed on the boss tip surface, the other end is exposed on the outer surface of the electronic device case, and the area of the outer surface side end surface of the insert member is larger than the boss tip side end surface of the insert member. Adopted structure.

According to these structures, heat can be efficiently radiated from the screw-down portion (boss) through the heat-radiating through-hole or the insert member. Can be prevented.

Further, according to the present invention, a heat radiating portion is fixed in the electronic device by a predetermined fixing means (for example, a screw), and a part of the radiating portion contacts the heat source in the electronic device to radiate the heat. In the plate, a slit is formed, for example, in a spiral shape between a heat source contact portion that contacts the heat source and a fixing device contact portion (for example, a portion where a screw hole is formed) that contacts the fixing device. The length of the heat conduction path from the heat source contact portion to the fixing means contact portion is longer than the distance between the heat source contact portion and the fixing device contact portion by the slit.

According to such a structure, it is possible to suppress an increase in the temperature of the fixing means contact portion due to heat from the heat source due to the length of the heat conduction path.

Further, according to the present invention, there is provided an electronic device case having a screwing portion formed with a screw hole for tightening a screw, and a predetermined member fixed to the screwing portion of the case by screwing. In the electronic device having a screw hole, a heat dissipation through-hole is formed around the screw hole of the screw screw portion of the case, and a screw screw hole for screwing the screw screw of the predetermined member is formed. A structure in which a ventilation hole communicating with the through hole is formed around the periphery is adopted.

According to such a structure, heat can be efficiently radiated from the screwed portion through the through hole and the ventilation hole.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

[First Embodiment] A first embodiment of the present invention will be described with reference to FIGS. First, FIGS.
1 is a top view, a side view, and a cross-sectional view taken along line AA of FIG. 1 showing a structure of a boss for screwing a circuit board, which is provided on a lower case constituting a main body case of an electronic device according to a first embodiment. It is.

In FIGS. 1 to 3, reference numeral 3 denotes a lower case constituting a main body case of an electronic device together with an upper case (not shown), which is made of plastic. On the inner surface of the lower case 3, a boss 16 for screwing a circuit board screw is formed integrally with the lower case 3 so as to project therefrom. A conventional boss for screwing a circuit board has a structure in which a screw hole for simply tightening a screw is formed. On the other hand, the boss 16 of the present embodiment is formed in a cylindrical shape as a whole, and is provided around the center portion 18 of the boss where the screw hole 21 is formed at the center, that is, around the screw hole 21 for heat dissipation by air cooling. Through hole 2
0 is formed in parallel with the screw hole 21, that is, along the axial direction of the boss 16, from the tip end surface of the boss 16 to the outer surface (the lower surface in FIG. 3) of the lower case 3. An outer peripheral portion outside the boss is formed as a wall 17 surrounding the boss central portion 18, and reinforcing ribs 19 connecting the boss central portion 18 and the wall 17 along the radial direction of the boss 16 are spaced by 90 degrees here. The through hole 20 is divided into four arc-shaped portions each having a little less than 90 degrees. Through hole 2
Insufficient strength of the boss central portion 18 due to the provision of 0 can be compensated for by the reinforcing ribs 19.

Next, FIG. 4 shows a state in which the circuit board 8 is fixed on the boss 16 by screws 12. The circuit board 8 is placed on the boss 16, the screw 12 is passed through a screw hole 81 provided in the board 8, and the screw 12 is tightened into the screw hole 21 of the boss 16, whereby the board 8 is fixed on the boss 16. You.

Here, the heat generated from the CPU 25 mounted on the substrate 8 is transferred to a ground pattern (not shown) formed on the surface of the substrate 8 (which may be another conductive pattern or a metal film pattern dedicated to heat conduction) and the substrate 8. And reaches the screw 12, and is further transmitted to the central portion 18 of the boss 16 via the screw 12. The outer periphery of the boss center 18 is a through hole 2
Because it is always in contact with the outside air by 0,
Heat is efficiently released into the outside air.

Next, as a method for further increasing the heat radiation efficiency, a top view of a structure in which a hole for ventilation is provided in the substrate 8 is shown in FIG.
And a cross-sectional view is shown in FIG.

In FIGS. 5 and 6, ventilation holes are provided around a screw hole 81 of the circuit board 8 at a plurality of positions which do not interfere with the head 13 of the screw 12 and communicate with the through hole 20 of the boss 16. Hole 22 is formed.

According to such a structure, as shown in FIGS. 5 and 6, the substrate 8 is fixed to the boss 12 with the screw 12, and the lower case 3 is connected to the lower case 3 through the through-hole 20 and the hole 22 through which outside air communicates. The heat transmitted to the boss 16 can be released more efficiently because the air is ventilated into the main body case (not shown) and the air in the main body case is ventilated outside through the holes 22 and 20. .

According to the above configuration, the heat transmitted from the CPU 25 to the boss 16 via the board 8 and the screw 12 is transferred to the boss 16.
The lower case 3 is efficiently discharged into the outside air without being stored in the lower case 3, and problems such as thermal deformation around the boss 16 of the lower case 3 due to heat storage and loosening of the screw 12 can be prevented.

[Second Embodiment] FIG. 7 is a sectional view showing a second embodiment of the present invention. In FIG.
The circuit board 8 is fixed to the boss 16 of the lower case 3 by screws 12 together with the shield plate 9 for shielding noise.

In the present embodiment, the structure of the boss 16 is slightly different from that of the first embodiment, and a screw hole 21 is formed.
The flanged insert member 23 made of metal or the like having a higher thermal conductivity than the plastic of the lower case 3 is attached to the boss central portion 18.
It is embedded by press-fitting or insert molding. One end (the upper end in the figure) of the insert member 23 is exposed on the tip end surface of the boss 16, and the other end (the lower end in the figure) is exposed on the outer side surface of the lower case 3. A flange is formed at an end on the outer surface side, and the end surface is shown as a flange surface 231. The position of the insert member 23 depends on the position of the flange.
The area of the end surface (flange surface 231) on the side that emits heat (the outer surface side of the lower case 3) is larger than the end surface on the side that absorbs the heat (the end side of the boss 16).

The structure of the other portions of the boss 16 is the same as that of the first embodiment, and the wall 17, the through hole 20, and the reinforcing rib 19 not shown in FIG.

According to this embodiment, the heat from the CPU 25 mounted on the circuit board 8 is transmitted through the substrate and the pattern of the board 8 and reaches the screw 12 and is transmitted to the flanged insert member 23 of the boss 16. Then, it is discharged to the outside from the flange surface 231 exposed on the outer surface of the lower case 3. Further, it is transmitted from the insert member 23 to the outer peripheral portion of the boss central portion 18, and is discharged into the outside air through the through hole 20.

According to the present embodiment, the through hole 2 of the boss 16
Since the heat is radiated through the flanged insert member 23 together with the heat radiated through the boss 16, the heat radiating efficiency can be further improved as compared with the first embodiment, and the heat storage and the temperature rise in the boss 16 can be suppressed. In particular, the insert member 23 described above.
The heat radiation efficiency of the insert member 23 can be improved due to the size relationship between the heat release side and the heat absorption side.

In FIG. 7, the flange surface 231 of the flanged insert member 23 is flat. However, if a plurality of ribs are provided on the flange surface 231 to increase the area of the flange surface 231, the heat radiation effect is further improved. The required heat dissipation capacity can be obtained by increasing or decreasing the area of the flange surface 231.

FIG. 8 shows another application example of the present embodiment, in which the temperature rise of the CPU cannot be reduced only by natural air cooling, so that a heat sink 26 made of a metal having a high thermal conductivity as another component is provided. FIG. A CPU (not shown) contacts one end of the heat sink 26, and a screw hole 261 is provided at the other end. Then, the position of the screw hole 261 is aligned with the screw hole 81 of the circuit board 8, the end of the heat sink 26 is overlapped on the circuit board 8, and the screw 12 is passed through the screw holes 261 and 81, and the lower case is inserted. The heat sink 26 is fixed to the boss 16 together with the substrate 8 by tightening the screw hole 21 of the flanged insert member 23 of the third boss 16.

In this case, the heat transmitted from the CPU to the boss 16 is the sum of the heat transmitted from the CPU to the board 8 and the heat transmitted to the heat sink 26 as a separate component, and the amount of heat transmitted is large. By increasing the area of the flange surface 231 of the 23, the heat radiation efficiency can be increased and the temperature rise of the boss 16 can be suppressed.

In this embodiment, a ground pattern or another conductive pattern or a pattern dedicated to heat conduction provided on the substrate 8 is provided so as to be in contact with the upper surface of the insert member 23, so that the thermal conductivity is further improved. I can do it.

[Third Embodiment] Next, a third embodiment of the present invention will be described with reference to FIGS.

FIG. 9 is a top view of the heat sink 29 used in this embodiment. The heat radiating plate 29 is made of a metal having a high thermal conductivity. At four corners of the heat radiating plate 29, screw holes 2 for fixing the heat radiating plate 29 together with the circuit board 8 to the boss 16 with the screws 12 are provided.
8 are provided. Further, a helical slit 27 is formed in the heat radiating plate 29, and a central portion surrounded by the slit 27 is bent so as to fall down one step,
A step-down plane portion 30 is provided to be brought into contact with an electronic component of a heat source requiring heat radiation.

FIG. 10 is a sectional view showing a state in which the radiator plate 29 and the circuit board 8 are fixed on the boss 16 of the lower case 3 and assembled to the lower case 3. The heat dissipation plate 29 is placed on the substrate 8 by aligning the screw holes 28 and 81, and the screws 12 are passed through the screw holes 28 and 81 and fastened to the screw holes of the boss 16 so that the heat dissipation plate 29 is 8 and fixed on the boss 16. Before that, a heat conductive sheet 31 made of a material having high heat conductivity is placed on the upper surface of the CPU 25,
Is fixed as described above, the position of the stepped flat portion 30 matches the upper surface of the heat conductive sheet 31 on the CPU 25. Here, by providing the spiral slit 27, the step-down plane portion 30 has elasticity,
The heat conductive sheet 31 on the U25 is always in pressure contact with the heat conductive sheet 31. The boss 16 has the same structure as that of the second embodiment.

In this case, part of the heat of the CPU 25 is transmitted to the substrate 8, but most of the heat is transferred to the heat conductive sheet 3 having a high thermal conductivity.
1 to the step-down plane portion 30 at the center of the heat sink 29. Then, the slit 27 from the step-down plane portion 30
Through the narrow spiral path inside the screw hole 2 at the end
Heat is transmitted to eight portions, and further transmitted to the boss 16 via the screw 12 and the substrate 8. Here, the heat conduction path from the step-down plane portion 30 to the screw-down hole 28 is narrowed by the slit 27, and the length of the heat conduction path is remarkably larger than the distance between the step-down plane portion 30 and the screw-down hole 28. By lengthening and reducing the thermal gradient, the temperature rise near the screw hole 28 is suppressed,
It is possible to suppress a rise in the temperature of the boss 16.

Further, the boss 16 has the same structure as that of the second embodiment, and can efficiently dissipate heat by the heat dissipated by the flanged insert member 23 and the heat dissipated by the through hole 20. Thermal deformation of the peripheral part and loosening of the screw can be prevented.

By the way, in each of the above embodiments,
The boss 16 is used for screwing the circuit board 8, the heat sink 26, or the heat radiating plate 29. However, it is needless to say that the boss 16 is preferably used for screwing a member which requires heat radiation.

Although the shape of the boss 16 is cylindrical,
The present invention is not limited to this, and may be, for example, an elongated ridge shape. Further, when the lower case 3 is provided with a flat screw portion without protruding like the boss 16, a through hole for heat radiation similar to the through hole 20 is formed around the screw hole of the screw portion. It may be formed.

In the third embodiment, the heat radiating plate 29 is fixed to the lower case 3 with a screw. However, other fixing brackets and adhesives are used at portions corresponding to the portions where the screw holes 28 are formed. It may be fixed by fixing means such as.

[0043]

As described above, according to the electronic device of the present invention and the case thereof, the electronic device is formed around the screw hole of the screwing portion for screwing the predetermined member such as the circuit board of the case. Through holes for heat dissipation by air cooling, or through an insert member embedded in a boss as a screwing portion, and further, through a ventilation hole formed around a screwing hole of a predetermined member to be screwed, Heat can be efficiently radiated from the screwing portion of the electronic device case, and problems such as thermal deformation around the screwing portion and loosening of the screw due to heat storage in the screwing portion can be prevented.

According to the heat sink of the present invention, for example, a helical slit formed between the heat source contact portion that contacts the heat source and the fixing device contact portion that contacts the fixing device such as a screw is provided. The length of the heat conduction path from the heat source contact to the fixing means contact is longer than the distance between the heat source contact and the fixing means contact, so that the temperature of the fixing means contact due to heat from the heat source It is possible to obtain an excellent effect that the rise can be suppressed and a problem such as a thermal deformation around the fixing portion of the heat sink of the electronic device case due to the temperature rise can be prevented.

[Brief description of the drawings]

FIG. 1 is a top view showing a structure of a boss for screwing a circuit board in a lower case of an electronic device according to a first embodiment of the present invention.

FIG. 2 is a side view showing the structure of the boss.

FIG. 3 is a sectional view showing the structure of the boss.

FIG. 4 is a sectional view showing a state where a circuit board is screwed to the boss.

FIG. 5 is a top view showing a state in which a circuit board having a ventilation hole formed in the boss is screwed.

FIG. 6 is a cross-sectional view showing a state in which a circuit board having a ventilation hole formed in the boss is screwed.

FIG. 7 is a cross-sectional view showing a state where a circuit board is screwed to a screwing boss in the second embodiment.

FIG. 8 is a sectional view showing a state in which a heat sink is screwed together with the circuit board with respect to the boss.

FIG. 9 is a top view illustrating a structure of a heat sink according to a third embodiment.

FIG. 10 is a cross-sectional view showing a state where the heat sink is screwed together with a circuit board to a boss.

FIG. 11 is a perspective view illustrating an appearance of a conventional electronic device.

FIG. 12 is a cross-sectional view showing a heat dissipation structure in the electronic device.

[Explanation of symbols]

 3 Lower case 8 Circuit board 9 Shield plate 12 Screw 18 Boss center part 19 Reinforcement rib 20 Through hole 21 Screw hole 22 Ventilation hole 23 Insert member with flange 25 CPU 26 Heat sink 27 Slit 28 Screw hole 29 Heat sink 30 steps Falling plane part 31 Thermal conductive sheet

Claims (8)

[Claims] 1. An electronic device case having a screwing portion for screwing a predetermined member, wherein a through hole for heat dissipation by air cooling is formed around a screw hole for tightening a screw of the screwing portion. An electronic device case characterized by being made. 2. The electronic device case according to claim 1, wherein the screwing portion is a screwing portion for screwing at least a circuit board. 3. The electronic device case according to claim 1, wherein the screwing portion is formed as a boss so as to protrude inward. 4. An insert member having a screw hole formed therein for tightening a screw is embedded in the center of the boss, one end of the insert member is exposed at a tip end surface of the boss, and the other end of the insert member is provided in an electronic device case. 4. The electronic device case according to claim 3, wherein the outer surface is exposed on an outer side surface, and an area of the end surface on the outer surface side is formed larger than an end surface on a boss tip side of the insert member. 5. 5. A radiator plate fixed by predetermined fixing means in an electronic device, a part of which contacts a heat source in the electronic device to radiate heat of the heat source. A slit is formed between the source contact part and the fixing means contact part which contacts the fixing means, and the length of the heat conduction path from the heat source contact part to the fixing means contact part is changed by the slit. A heat sink, wherein the distance is longer than the distance between the contact portion and the fixing means contact portion. 6. The heat sink according to claim 5, wherein the slit is formed in a spiral shape. 7. An electronic device, wherein the electronic device is fixed by a screw.
The heat sink according to claim 5 or 6, wherein the fixing means contact portion has a portion in which a hole for screwing is formed. 8. An electronic device case having a screw-down portion formed with a screw hole for tightening a screw, and a predetermined member fixed to the screw-down portion of the case with a screw-down. In the above, a through hole for heat dissipation by air cooling is formed around a screw hole of a screw portion of the case, and the through hole is formed around a screw hole through which a screw for screwing the predetermined member passes. An electronic device, wherein a hole for ventilation communicating with the hole is formed.