JP2000022368A - Heat dissipation unit for electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance performance for dissipating heat to the outside of housing. SOLUTION: The heat dissipation unit is built in a notebook-sized personal computer 1 in order to dissipate heat generated from a CPU 5 arranged in a housing 3 to the outside. The heat dissipation unit comprises a horizontal aluminum substrate 7 arranged in the housing 3, a flat heat pipe 8 bonded to the lower surface of the substrate 7 in surface contact state, and heat dissipation fins 17 fixed to the opposite sides of the heat pipe 8 while touching a part of the face which does not come into surface contact with a metal substrate. Heat dissipation openings 19 are made in the circumferential wall of the housing 3 in the vicinity of the fin 17 while facing the fin 17. A fan 20 passes the air in the housing 3 through the fins 17 and then delivers the air from the opening 19 to the outside of the housing 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat radiating device for use in an electronic device, particularly preferably a portable electronic device, which radiates heat generated from an electronic component disposed in a housing of the electronic device to the outside of the housing.

[0002]

2. Description of the Related Art For example, portable electronic devices such as notebook personal computers, laptop personal computers, and other portable computer devices have electronic components such as a central processing unit (CPU). It is necessary to radiate the heat generated from the parts to the outside of the housing.

For example, a notebook personal computer generally includes a thin housing having a keyboard, and a display device provided to be freely opened and closed with respect to the housing. In the housing, a circuit board and a CP mounted on the circuit board
U.

As a heat radiating device from the CPU of the notebook type personal computer described above, the applicant of the present invention has previously formed two metal plates crimped to each other and formed a hollow pattern having a required pattern between the two metal plates. A horizontal metal substrate provided with a heat pipe portion is formed in the housing by forming the working fluid sealing portion and filling the working fluid into the working fluid sealing portion, and the heat pipe portion generates heat generated from the electronic component. A device having a heat receiving part for receiving the heat has been proposed (see Japanese Patent Application Laid-Open No. 10-122774).

In such a heat radiating device, a heat-generating electronic component such as a CPU is brought into contact with a heat receiving portion of a heat pipe portion of a metal substrate. The heat generated from the heat-generating electronic components is transmitted to the heat receiving section of the heat pipe section, and the heat heats the working fluid stored in the heat receiving section of the heat pipe section to evaporate. Flows away from the heat receiving portion, and radiates heat to the air in the housing via the metal substrate. The heat of the heated air inside the housing is radiated outside the housing via the keyboard.

[0006]

By the way, in the field of portable electronic equipment, recently, multifunctionality and processing speed have been remarkably increased, and as a result, the output of heat-generating electronic components such as a CPU has increased, and the amount of heat generated has increased. It has increased significantly. Therefore, in the above-mentioned conventional heat radiating device, the heat radiating performance to the outside of the housing is becoming insufficient.

An object of the present invention is to provide a heat radiating device for electronic equipment which solves the above-mentioned problem and has more excellent heat radiating performance to the outside of a housing than a conventional heat radiating device.

[0008]

According to the first aspect of the present invention, there is provided a heat radiating device for an electronic device, wherein the heat radiating from an electronic component provided in the electronic device and disposed in a housing of the electronic device is provided. A heat dissipating device that dissipates heat to a horizontal metal substrate disposed in a housing, a flat heat pipe joined to one of upper and lower surfaces of the metal substrate in a surface contact state, and a heat pipe. A heat radiation fin mounted so as to be in contact with a part of the both surfaces that are not in surface contact with the metal substrate; a heat radiation opening is formed near the heat radiation fin on the peripheral wall of the housing; It faces the opening for use.

In the heat radiating device for electronic equipment according to the first aspect of the present invention, the heat generating electronic components such as the CPU are brought into contact with a heat receiving portion of the heat pipe at a predetermined distance from a portion where the heat radiating fin is mounted. The heat generated from the heat-generating electronic components is transmitted to the heat pipe, and the heat heats the working fluid stored in the heat receiving portion of the heat pipe where the electronic components are brought into contact, evaporates, and the generated gaseous working fluid is heated. Flow away from the heat receiving part in the pipe,
The heat is radiated to the air in the housing via the container wall of the heat pipe and the metal substrate and reliquefied. The heat of the heated air inside the housing is radiated to the air outside the housing via the keyboard. The gaseous working fluid that has flowed to the portion of the heat pipe to which the heat radiating fins are attached releases heat to the air in the housing via the container wall of the heat pipe and the heat radiating fins to be reliquefied. Therefore, the heat transfer area to the air in the housing increases. In addition, since the heat radiation fin faces the heat radiation opening, heat is radiated directly to the air outside the housing through this opening. As a result, the radiation efficiency is improved in the portion where the radiation fins are attached as compared with other portions. The re-liquefied working fluid returns to the heat receiving section. The working fluid originally stored in a portion of the heat pipe other than the heat receiving portion flows to the heat receiving portion. By repeating such an operation, heat generated from the electronic component is radiated. Therefore, the heat dissipation performance is improved as compared with the conventional heat dissipation device which dissipates heat only to the air in the housing and further radiates out of the housing via the keyboard.

According to a second aspect of the present invention, there is provided a heat radiating device for electronic equipment according to the first aspect of the present invention, wherein the air in the housing is
The fan is provided with a fan that passes through the heat radiation fins and then out of the housing through the heat radiation opening. In this case, when the fan is activated, the heated air in the housing will
Since the heat is sent to the outside of the housing through the heat-dissipating opening, heat is not stored in the housing, and the heat-dissipating performance is further improved. Moreover, since the air passes through the radiation fins, the radiation efficiency from the radiation fins is improved.

According to a third aspect of the invention, there is provided a heat radiating device for electronic equipment according to the first or second aspect, wherein the heat pipe includes a flat tubular container having both ends closed.
A flat tubular container, flat upper and lower walls, both side walls spanning both side edges of the upper and lower walls, and a plurality of reinforcing walls extending between the two side walls and extending in the longitudinal direction and extending in the length direction and spaced from each other. In the container, a plurality of hydraulic fluid sealed portions partitioned by reinforcing walls are formed in parallel. In this case, the function of the reinforcing wall improves the pressure resistance of the heat pipe and increases the heat transfer area with the working fluid in the flat tubular container, thereby improving the heat radiation efficiency.

According to a fourth aspect of the present invention, there is provided a heat radiating device for electronic equipment according to the third aspect of the present invention, wherein the flat tubular container is formed of a hollow extruded member.

According to a fifth aspect of the present invention, there is provided a heat radiating device for electronic equipment according to the fourth aspect of the present invention, wherein a plurality of inner fins extending in a pushing direction are integrally formed on an inner peripheral surface of the working fluid sealing portion. is there. In this case, the heat transfer area with the working fluid in the flat tubular container increases, and the heat radiation efficiency improves. In addition, a wick effect can be obtained.

According to a sixth aspect of the present invention, there is provided the heat radiating device for electronic equipment according to the third aspect, wherein the flat tubular container is made of a metal plate-shaped upper component having an upper wall forming portion and a metal having a lower wall forming portion. A lower projecting wall formed by a plate-shaped lower component, and both side walls of the flat container are integrally formed in a lower ridge shape on both sides of the upper component and brazed to the lower component, and both sides of the lower component. At least one of an upper protruding wall formed integrally with the upper component and brazed to the upper component, wherein the reinforcing wall forms an upper wall forming portion of the upper component and a lower wall of the lower component. The reinforcing wall is formed integrally with at least one of the portions in an inwardly protruding manner, and has a tip formed by a reinforcing wall forming portion brazed to the other end. In this case, the thickness of the container can be reduced as compared with the case where the flat tubular container is formed of a hollow extruded shape member, so that the heat transfer to the metal substrate and the radiation fins is excellent.

According to a seventh aspect of the present invention, there is provided the heat radiating device for electronic equipment according to the sixth aspect of the present invention, wherein the reinforcing wall is formed with a communication hole through which the parallel working fluid sealing portions are passed. In this case, the working fluid can be spread evenly over the entire heat pipe, and the temperature of the heat radiating section can be equalized.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described.
This will be described with reference to the drawings. In the following description,
The left and right in FIG. 2 are referred to as left and right, and the lower side of FIG. 2 is referred to as front, and the opposite side is referred to as rear. Also, in the following description,
The term "aluminum" shall include aluminum alloys in addition to pure aluminum.

FIGS. 1 to 3 show the entire structure of a notebook personal computer provided with a heat radiating device according to the present invention, and FIGS. 4 and 5 show a part of the computer in an enlarged manner.

1 to 3, a notebook personal computer (1) comprises a thin housing (3) having a keyboard (2) and a display device (3) provided to be openable and closable with respect to the housing (3). 4)
Then, a circuit board (6) on which a CPU (5) is mounted is arranged in the housing (3).

In the portion of the housing (3) between the keyboard (2) and the circuit board (6), make a small gap between the keyboard (2) and the keyboard (2). The horizontal aluminum substrate (7) is placed in a state where it is placed. The aluminum substrate (7) has a rectangular shape elongated in the left-right direction, and is almost the same size as the keyboard (2). A flat heat pipe (8) is brazed to the lower surface of the aluminum substrate (7) in surface contact. heat pipe
(8) is substantially L-shaped when viewed from above, and comprises a long portion (8a) along the front side of the aluminum substrate (7) and a short portion (8b) along the left side. The heat pipe (8)
It has a flat tubular container (9) that is substantially L-shaped when viewed from a plane closed at both ends. As shown in FIG.
(9) is flat upper and lower walls (10) and (11), both side walls (12) straddling both side edges of the upper and lower walls (10) and (11), and the upper and lower walls (10) and (11) ) And a plurality of reinforcing walls (13) extending in the length direction and spaced from each other and formed by bending an aluminum flat hollow extruded shape into an approximately L-shape. It was done. container
The upper wall (10) of (9) is brazed to the aluminum substrate (7) in surface contact. In the container (9), a plurality of hydraulic fluid filling portions (14) having a circular cross section and partitioned by a reinforcing wall (13) are formed in parallel. Both ends of the reinforcing wall (13) are cut off over a predetermined length, so that the container (9)
Communication portions (25) through which all the working fluid sealing portions (14) pass are formed at both ends of the inside. Heat pipe (8)
An aluminum plate (15) is attached via a highly heat conductive elastomer (not shown) at the center of the length on the lower surface of a). And the aluminum plate of the heat pipe (8)
The portion to which (15) is attached serves as a heat receiving portion (16) for receiving heat generated from the CPU (5). The working fluid for the heat pipe (8) includes PFC, HFC134a, CFC
FC113, HCFC123, etc. are used.

Radiation fins (17) made of aluminum corrugated fins on the lower surface of the short portion (8b) of the heat pipe (8)
Is installed. As shown in FIG.
7) is arranged so that the crest and bottom of the crest extend in the front-rear direction, and the crest is a highly thermally conductive elastomer (not shown).
Through the heat pipe (8) and attached to the aluminum substrate (7) by the aluminum cover (18) fixed to the aluminum substrate (7) while straddling the heat pipe (8). Have been. Note that the wave crest of the radiation fin (17) may be brazed to the lower surface of the heat pipe (8). The cover (18) is substantially U-shaped when viewed from the front, and its front and rear ends are open. A bent portion (18b) projecting outward in the left-right direction is integrally formed at the upper end of a pair of left and right vertical walls (18a) of the cover (18).
b) the adhesive, welding,
It is fixed by brazing or the like. The cover (18) may be mechanically fixed to the aluminum substrate (7).
Further, corrugated fins with louvers may be used as the radiation fins (17). Further, other types of fins may be used as the radiation fins (17) instead of the corrugated fins.

Notebook type personal computer
At the left end of the rear wall (3a) of the housing (3) of (1), a heat dissipation opening
(19) is formed, and the rear end of the radiation fin (17) faces the radiation opening (19). Also, in a portion between the heat radiation opening (19) and the heat radiation fin (17) in the housing (3),
An axial fan (20) whose rotation axis is oriented in the front-rear direction is arranged and attached to the board (7) and the cover (18). The suction side opening of the casing (20a) of the axial fan (20) is covered
(18). An intake port (21) is formed at the front end of the left side wall (3b) of the housing (3). Axial fan (20)
After passing the air inside the housing (3) through the radiating fins (17) and sending it out of the housing (3) through the radiating opening (19), the air outside the housing (3) also flows through the air inlet (21). It is for inhaling. After passing the air inside the housing (3) through the radiating fins (17), send it out of the housing (3) through the radiating opening (19), and suck the air outside the housing (3) through the air inlet (21) Not only axial fans but also other types of fans can be used.

In the above notebook personal computer (1), the CPU (5) mounted on the upper surface of the circuit board (6) is an aluminum plate (15) on the lower surface of the heat receiving portion (16) of the heat pipe (8). Is closely associated with. CPU
The heat generated from (5) is transmitted to the hydraulic fluid in the heat receiving part (16) of the heat pipe (8) via the aluminum plate (15), highly heat conductive elastomer and the lower wall (11) of the container (9). ,
The working fluid heated by this heat evaporates here to become a gaseous working fluid. The gaseous hydraulic fluid flows through the long part (8a) of the heat pipe (8) toward the right end, and the upper wall (10) of the container (9), the aluminum substrate (7) and the keyboard
Heat is dissipated to the air outside the housing (3) via (2) and to the air inside the housing (3) via the lower wall (11) and the upper wall (10) and the board (7). Liquefy. The re-liquefied working fluid flows back and returns to the heat receiving section (16). The gaseous working fluid generated in the heat receiving section (16) is supplied to the heat pipe (8).
Flows toward the left end in the long portion (8a), and flows into the short portion (8b). A part of the gaseous working fluid radiates heat to the air inside and outside the housing (3) even before flowing into the short portion (8b), and is partially reliquefied. The gaseous hydraulic fluid flowing into the short section (8b) is transferred to the upper wall (10) of the container (9)
(7) and the keyboard (2) to dissipate heat to the air outside the housing (3), as well as to the lower wall (11) and the radiation fins (1).
Heat is released to the air inside the housing (3) via 7) and re-liquefied. The re-liquefied working fluid returns to the heat receiving section (16). Also, the working fluid originally stored in the heat pipe (8) except for the heat receiving part (16) flows to the heat receiving part (16). By repeating such an operation, the heat generated from the CPU (5) is radiated to the air in the housing (3). At this time,
With the fan (20) turned on, the heated air in the housing (3) passes through the heat dissipation opening (19) and the housing (3)
In addition to discharging to the outside, air outside the housing (3) is drawn into the housing (3) through the air inlet (21). Then, heat is not stored in the housing (3), and low-temperature air sucked from outside the housing (3) passes through the radiating fins (17), so that the efficiency of radiating heat from the radiating fins (17) is improved.

In the above embodiment, the heat pipe
(8) is brazed to the lower surface of the aluminum substrate (7), but the heat pipe (8) may be brazed to the upper surface of the aluminum substrate (7), or
(7) The upper and lower surfaces may be brazed. Further, the heat pipe (8) may be welded to the aluminum substrate (7). In addition, the heat pipe (8) is
(7) may be attached with a high thermal conductive elastomer or an adhesive.

FIG. 6 shows a modification of the flat tubular container (9) of the heat pipe (8). In FIG. 6, a plurality of inner fins (30) extending in the length direction are integrally formed on the inner peripheral surface of the working fluid sealing portion (14) of the container (9) at intervals in the circumferential direction.

FIG. 7 shows another modification of the flat tubular container (9) of the heat pipe (8).

In FIG. 7, the reinforcing wall (13) of the container (9)
A plurality of communication holes (40) through which the working fluid sealing portions (14) are arranged in parallel with each other are formed. The communication holes (40) are staggered when viewed from above. When the communication hole (40) is formed, the working fluid flowing through the parallel working fluid enclosure (14) is
It flows in the width direction of the heat pipe (8) through the communication hole (40),
It is mixed throughout all the working fluid enclosures (14).

The container (9) has an upper wall (10) and both side walls (1).
Formed by an aluminum plate-shaped upper component member (41) constituting the 2) and an aluminum plate-shaped lower component member (42) constituting the lower wall (11), both side walls (12) and the reinforcing wall (13). It was done. The upper component member (41) includes an upper wall forming portion (43), and a lower protruding wall (44) integrally formed on each side edge of the upper wall forming portion (43) in a downwardly protruding shape. The lower constituent member (42) includes a lower wall forming portion (45), an upper protruding wall (46) integrally formed on each side edge of the lower wall forming portion (45) in an upwardly protruding shape, and a lower wall forming portion (45). Four
5) a plurality of reinforcing wall forming parts (4
7). A plurality of upwardly projecting projections (50) are integrally formed at intervals in the longitudinal direction at portions between adjacent reinforcing wall forming portions (47) on the upper surface of the lower wall forming portion (45). I have. A plurality of notches (48) are formed in the upper edge of the reinforcing wall forming portion (47) at intervals in the length direction, and the reinforcing wall forming portion (47)
The end of the notch (48) is brazed to the upper wall (10) and the opening of the notch (48) is closed by the upper wall (10) so that the communication hole (4
0) is formed. On both side edges of the lower surface of the lower component (42), an inclined surface (49) inclined upward toward both sides.
Are formed.

The upper component (41) and the lower component (42)
The lower projecting wall (44) of the upper component (41) is
The lower protruding wall (44) is bent inward so that the lower end of the lower protruding wall (44) is bent inward, and the inward bent portion (44a) is formed on the inclined surface (49). The two members (41) and (42) are temporarily fixed by being brought into close contact engagement.In this state, the upper protruding wall (46) and the lower protruding wall (44) are brazed to each other, and the reinforcing wall is formed. The container (9) is formed by brazing the tip of the portion (47) to the upper wall forming portion (43) and further brazing the inward bent portion to the inclined surface (49).

FIG. 8 shows another embodiment of the heat radiator according to the present invention.

In FIG. 8, there is provided a duct (60) connected to the front end of the cover (18) and guiding the air outside the housing (3) sucked from the air inlet (21) to the radiation fins (17).
The duct (60) has the same cross-sectional shape as the cover (18),
The front end of (18) extends forward and is bent to the left, and its front end faces the intake port (21). Further, a portion of the duct (60) that interferes with the heat pipe (8) is cut off. Other configurations are the same as those of the embodiment shown in FIGS. 1 to 5, and the same portions are denoted by the same reference numerals.

In this embodiment, when the fan (20) is operated, low-temperature air outside the housing (3) is sucked in from the air inlet (21), and the low-temperature air is radiated through the duct (60). The air guided by the fins (17) and heated by the heat radiated from the radiating fins (17) is discharged out of the housing (3) through the radiating opening (19). Therefore, the heat radiation performance of the gaseous working fluid flowing into the short portion (8b) via the heat radiation fins (17) is improved.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a notebook personal computer provided with a heat radiating device according to an embodiment of the present invention.

FIG. 2 is a horizontal sectional view showing a notebook personal computer including the heat radiating device according to the embodiment of the present invention.

FIG. 3 is an enlarged sectional view taken along the line III-III of FIG. 2;

FIG. 4 is an enlarged sectional view taken along line IV-IV of FIG. 2;

FIG. 5 is an enlarged sectional view taken along line VV of FIG. 2;

FIG. 6 is a cross-sectional view showing a modification of the heat pipe container.

FIG. 7 is a partially cutaway perspective view showing still another modified example of the heat pipe container.

FIG. 8 is a partially cutaway horizontal sectional view showing a notebook personal computer provided with a heat radiating device according to another embodiment of the present invention.

[Explanation of symbols]

(1): Notebook type personal computer (electronic device) (3): Housing (5): CPU (electronic component) (7): Aluminum substrate (metal substrate) (8): Heat pipe (9): Container (10) ): Upper wall (11): Lower wall (12): Both side walls (13): Reinforced wall (14): Hydraulic fluid filling part (17): Radiation fin (19): Radiation opening (20): Fan (30 ): Inner fin (40): Communication hole (41): Upper component (42): Lower component (43): Upper wall forming part (44): Lower protruding wall (45): Lower wall forming part (46) : Upper projecting wall (47): Reinforced wall forming part

Claims (7)

[Claims] 1. A heat radiating device provided in an electronic device and radiating heat generated from an electronic component disposed in a housing of the electronic device to the outside of the housing, comprising: a horizontal metal substrate disposed in the housing; A flat heat pipe joined to one of the upper and lower surfaces of the metal substrate in a surface contact state, and a heat pipe attached to a part of the both surfaces of the heat pipe that are not in surface contact with the metal substrate. A radiator for an electronic device, comprising: a radiating fin; a radiating opening formed in a peripheral wall of the housing in the vicinity of the radiating fin; 2. The radiator for an electronic device according to claim 1, further comprising a fan that sends air in the housing through the radiating fins and then sends the air out of the housing through the radiating opening. 3. A heat pipe comprising a flat tubular container having both ends closed, the flat tubular container comprising flat upper and lower walls, both side walls spanning both side edges of the upper and lower walls, and upper and lower walls between the two side walls. A plurality of reinforcing walls extending in the longitudinal direction and extending at intervals from each other, and a plurality of hydraulic fluid sealing portions partitioned by the reinforcing walls are formed in a container in parallel. Item 3. An electronic device radiator according to item 1 or 2. 4. The heat radiating device for electronic equipment according to claim 3, wherein the flat tubular container is formed of a hollow extruded shape. 5. The heat radiating device for an electronic device according to claim 4, wherein a plurality of inner fins extending in the extrusion direction are integrally formed on an inner peripheral surface of the working fluid sealing portion. 6. A flat tubular container is formed by a metal plate-shaped upper component having an upper wall forming portion and a metal plate-shaped lower component having a lower wall forming portion, and both side walls of the flat container are formed with an upper side. A lower protruding wall integrally formed on both sides of the component in a downwardly protruding shape and brazed to the lower component, and an upper portion integrally formed on both sides of the lower component in an upwardly protruding shape and brazed to the upper component. The reinforcing wall comprises at least one of the protruding walls, and the reinforcing wall is integrally formed in an inwardly protruding shape with at least one of the upper wall forming portion of the upper component and the lower wall forming portion of the lower component. 4. The heat radiating device for an electronic device according to claim 3, further comprising a reinforcing wall forming portion whose tip is brazed to the other end. 7. The heat radiating device for an electronic device according to claim 6, wherein a communication hole through which the parallel working fluid sealing portions pass between the reinforcing walls is formed.