JP5127902B2 - Electronic device heat dissipation device and electronic device - Google Patents

Description

  The present invention relates to a heat radiating device having high efficiency used for an electronic device, and more particularly to a heat radiating device capable of suppressing an increase in casing temperature of the electronic device.

  In recent years, portable electronic devices such as notebook personal computers (hereinafter referred to as notebook PCs) generate heat due to improvements in the performance of electronic devices such as processors and video chips, and increased packaging density. The amount is increasing. In order to maintain the function of the electronic device housed in the housing, it is necessary to prevent the operating temperature from exceeding an allowable value. Furthermore, since the notebook PC is operated by being held by hand or placed on the knee, it is necessary to suppress the temperature rise of the casing.

  For this purpose, the notebook PC is equipped with a heat dissipation device consisting of a heat sink, heat pipe, and heat dissipation fan, forcibly exhausting the air taken from the outside with heat exchange By doing so, heat is released from inside or cooled. The heat sink is connected to a processor having the largest heat generation amount among electronic devices via a heat pipe, so that the temperature rises. Further, since the heat sink is disposed near the casing, the temperature of the casing is increased.

  Patent Document 1 discloses a heat dissipation system applied to a notebook PC. The heat dissipating system of the same document is provided with an air inlet and a plate in the vicinity of the heat sink, and heat is radiated from the plate by outside air sucked from the air inlet to suppress the temperature rise of the housing. Patent Document 2 discloses an electronic device cooling device that prevents local heating of a keyboard in the vicinity of a CPU by tilting and holding an axial fan for cooling inside the electronic device and guiding air to an exhaust port. To do.

  Patent Document 3 discloses a heat sink that smoothes air flow and improves heat dissipation performance. The heat sink described in the document includes a heat receiving plate that can be attached to a heat source, a heat radiating portion provided on the heat receiving plate, and a cooling fan provided so that cooling air can be blown to the heat radiating portion. ing. The heat dissipating part includes a heat transfer plate standing on the heat receiving plate at a predetermined interval and a heat dissipating fin arranged vertically between the heat transfer plates, and cooling between the lower end of the heat dissipating fin and the heat receiving plate. An air intake / exhaust space is formed.

JP 2008-112225 A JP 2000-227822 A JP 2007-42724 A

  In order to improve the heat dissipation capability of the heat dissipation device, it is common to increase the airflow (unit: CFM) of the heat dissipation fan to reduce the heat sink thermal resistance or increase the heat sink heat dissipation area. It is. The airflow of the heat dissipation fan can be increased by increasing the blade diameter or increasing the rotational speed. However, in order to adopt such a method for a notebook PC, there are points such as size, power consumption, and noise. There is a limit.

  The heat sink's heat dissipating capability is improved by increasing the heat dissipating area of the heat dissipating fins that come into contact with air, but there is a limit to the size of the heat sink that can be adopted in a notebook PC. When designing a heat dissipation system, heat is generated based on the heat resistance value (° C / W) required for the heat sink calculated from the heat value (W) of the electronic device and the rising temperature (° C) of the heat sink.・ Calculate the heat dissipation area of the sink. In the forced heat dissipation method in which air is forcibly sent to the heat sink by a heat dissipation fan, the heat resistance decreases and the heat dissipation capability improves as the flow velocity of air passing between the heat dissipation fins increases.

  Therefore, by increasing the air flow rate, the heat sink heat dissipation area can be reduced for the same heat dissipation capability, and the heat sink temperature can be further decreased for the same heat dissipation area. In the conventional heat dissipation system concept, the heat sink structure is determined as long as it can be housed in the housing, and the blade diameter of the heat dissipation fan is increased or the rotation speed is increased in order to increase the wind speed of the heat sink. It was increasing. The heat dissipation system mounted on the current notebook PC needs to be able to cope with an increase in the amount of heat generated at the same time as the demand for weight reduction, thickness reduction and size reduction. Furthermore, reduction of noise and power consumption is also required. Realizing such a heat dissipation system with various requirements by the conventional method has reached its limit.

  Many notebook PCs employ a centrifugal fan suitable for being housed in a thin casing as a heat dissipation fan. The centrifugal fan sucks air from the blade axial direction and exhausts it in a direction perpendicular to the shaft. In the centrifugal fan, the turbulent flow is generated near the discharge side of the blade as compared with the axial flow fan because the air flow is bent in a right angle direction. If this turbulent flow is rectified, it is considered that the flow velocity between the heat dissipating fins that should be originally obtained is obstructed, and the thermal resistance of the heat sink may be reduced by suppressing the turbulent flow.

  Although the method of Patent Document 1 is effective in suppressing the temperature rise of the housing, it cannot improve the heat dissipation performance of the heat sink. In addition, the method disclosed in Patent Document 1 provides an intake port at a predetermined position near the heat sink, which may require time and effort to adjust the overall air balance. Moreover, since the air flow path is formed between the plate and the bottom surface of the casing, the casing becomes thicker by that amount.

  Therefore, an object of the present invention is to provide a heat dissipation device suitable for weight reduction, thickness reduction, and size reduction. Furthermore, the objective of this invention is providing the heat radiating device which improved the heat dissipation capability. A further object of the present invention is to provide a heat dissipation device capable of reducing noise and power consumption. Furthermore, the objective of this invention is providing the heat radiating device which can suppress the temperature rise of a housing | casing. Furthermore, the objective of this invention is providing the electronic device which employ | adopted such a thermal radiation apparatus.

  A centrifugal fan is accommodated in the air chamber of the heat radiating device, and a heat sink is disposed around the centrifugal fan. The heat sink includes a plurality of radiating fins coupled to the first and second sidewalls to form a plurality of air flow paths. A slit-like conduction path is formed so as to extend in a direction perpendicular to the surfaces of the plurality of radiation fins. The air pressurized by the centrifugal fan is exhausted between the plurality of radiating fins and via the conduction path. The conduction path suppresses the turbulent flow at the entrance of the heat sink caused by the centrifugal fan, and improves the air flow by allowing the air to smoothly pass through the air flow path.

  The conduction path can be formed by a housing that forms a first side wall of the heat sink and an air chamber. The conduction path can also be formed as part of a heat sink. A heat pipe can be coupled to the second sidewall. The distance between the heat radiation fins and the height of the conduction path can be made substantially equal. Further, the height of the conduction path can be 3% or more and 13% or less of the height of the heat sink.

  According to the present invention, a heat dissipation device suitable for weight reduction, thickness reduction, and size reduction can be provided. Furthermore, according to the present invention, a heat dissipation device with improved heat dissipation capability could be provided. Furthermore, according to the present invention, a heat radiating device capable of reducing noise and power consumption can be provided. Furthermore, according to the present invention, it is possible to provide a heat radiating device capable of suppressing the temperature rise of the housing. Furthermore, according to the present invention, an electronic apparatus employing such a heat dissipation device could be provided.

It is the perspective view which looked at notebook PC concerning an embodiment of the invention from the front and back. It is a top view of the thermal radiation apparatus concerning this Embodiment. It is a partial perspective view of the thermal radiation apparatus concerning this Embodiment. It is the figure which showed typically the cross section seen from the AA arrow direction in the state attached to the system housing | casing with the heat dissipation apparatus of FIG. 2 (A) turned inside out. It is a figure explaining the heat dissipation capability of a thermal radiation apparatus. It is a figure explaining the mode of retention of the airflow in an air chamber. It is a figure which shows the example which formed the conduction path in the heat sink.

  FIG. 1 is a perspective view of a notebook PC 10 according to an embodiment of the present invention as viewed from the front and rear. In the notebook PC 10, a display housing 11 that holds a liquid crystal display device (LCD) 12 is opened from the system housing 15. A large number of electronic devices such as a central processing unit (CPU), a graphical processing unit (GPU), a main memory, and a hard disk drive (HDD) are housed in the system housing 15. These electronic devices increase in temperature during operation and become a heat source to increase the temperature inside the system housing 15.

  A keyboard 20 is disposed on the surface of the system housing 15 so as to be surrounded by the palm rest 21 and the keyboard edge frame 14. Further, an optical disk drive (ODD) 13 is attached to the side surface of the system housing 15, and exhaust ports 16 and 17 and intake ports 18 and 19 are formed. The system casing 15 houses a forced air-cooling type heat dissipation device that dissipates internal heat by forcibly sucking outside air from the intake ports 18 and 19 and exhausting it from the exhaust ports 16 and 17. .

  FIG. 2 is a plan view of the forced air-cooling type heat dissipation device 100 according to the present embodiment. FIG. 3 is a partial perspective view of the heat dissipation device 100 according to the present embodiment. 2A shows a state in which the fan cover 109 and the conduction path cover 111 are attached to the housing 151, and FIG. 2B shows a state where the upper portion of the housing 151, the fan cover 109 and the conduction path cover 111 are removed. Indicates the state. 3A corresponds to FIG. 2A, and FIG. 3B shows a state where the conductive path cover 111 is disassembled from the state of FIG. 3A.

  When the fan cover 109 and the conduction path cover 111 are attached to the housing 151, they become part of the housing 151 to form an air chamber. A centrifugal heat dissipation fan 101 and heat sinks 105 and 107 are attached to the housing 151. When the heat dissipation device 100 is mounted in the system housing 15, the position of the air outlet of the heat sink 107 is aligned with the exhaust port 16 of the system housing 15, and the air outlet of the heat sink 105 is connected to the exhaust port 17. The position is aligned.

  The heat radiating fan 101 sucks air that has flowed in from the outside through the air inlets 18 and 19 from the fan cover 109 provided at the upper and lower positions of the rotating shaft 103 and the air inlet of the housing 151 and discharges it in the radial direction of the blade. For example, the heat dissipating fan 101 has a blade diameter of 50 mm and a rotational speed of 3300 rpm. The air discharged from the heat radiating fan 101 enters the heat sinks 105 and 107 and is exhausted to the outside of the system casing 15 through the exhaust ports 16 and 17.

  The heat pipe 125 is thermally coupled to the heat receiving section 123 and the heat sink 107, the heat pipe 127 is thermally coupled to the heat receiving surfaces of the heat receiving section 121 and the heat sink 107, and the heat pipe 129 is heat received. It is thermally coupled to the endothermic surfaces of the part 121 and the heat sink 105. The heat pipe 129 is also thermally coupled to the housing 113. When the heat dissipation device 100 is attached to the system housing 15, the GPU and the south bridge are in thermal contact with the position 163 in the heat receiving unit 123, and the CPU is in thermal contact with the position 161 in the heat receiving unit 121.

  The housing 151 and the heat sinks 105 and 107 are each formed of a metal material having good thermal conductivity such as aluminum or copper. In the heat sinks 105 and 107, a plurality of slit-like air flow paths are formed with a plurality of heat radiating fins in order to increase the contact area between the metal material and air to increase the heat exchange rate. The heat radiating fins are formed of thin flat plates, are arranged in parallel so as to form air passages having a predetermined pitch, and are coupled to upper and lower side walls that are in the height direction of the heat sinks 105 and 107.

  In one example, the pitch of the radiating fins is 1 mm. For the heat sinks 105 and 107, the direction of the rotating shaft 103 of the heat radiating fan 101 is called the height direction, the direction perpendicular to the plane of the heat radiating fins is called the width direction, and the direction in which air flows through the air flow path is the depth direction. I will say. When the heat radiating fan 103 rotates, the heat received by the heat receiving unit 123 is radiated through the heat pipe 125 and the heat sink 107, and the heat received by the heat receiving unit 121 is radiated through the heat pipes 127 and 129 and the heat sinks 105 and 107. Is done. In addition, since the air flowing in from the intake ports 18 and 19 comes into contact with the electronic device inside the housing and then flows into the air chamber of the heat radiating device 100, the heat radiating device 100 only receives the heat received from the heat receiving units 121 and 123. In addition, the heat of other electronic devices housed inside the system housing 15 can also be dissipated.

  4A is a diagram schematically showing a cross section viewed from the direction of arrows AA in a state where the heat dissipating device 100 of FIG. FIG. 4B shows a cross-section at the same position when the conventional heat dissipation device 50 is attached to the same system casing 15. 4A differs from FIG. 4B in that the height of the heat sink 107 is different, and in FIG. 4A, a conduction path cover 111 is provided and one heat receiving surface of the heat sink 107 is provided. The only point is that a conduction path 157 is formed between the terminal 107a and the terminal 107a.

  4A and 4B, the heat dissipation device 100 is disposed between the keyboard edge frame 14 and the bottom surface 22 of the system housing 15. An intake port 153 is formed in the housing 151, and an intake port 155 is formed in the fan cover 109. 4A, the heat radiating fan 101 is disposed inside the air chamber 110 formed by the housing 151, the fan cover 109, and the conduction path cover 111. In FIG. 4B, the heat radiating fan 101 is formed by the housing 151 and the fan cover 109. A heat dissipating fan 101 is disposed inside the air chamber 110. On the exhaust port 16 side of the air chamber 110, a heat sink 107 is disposed in FIG. 4A, and a heat sink 51 is disposed in FIG. 4B.

  Heat pipes 125 and 127 are coupled to the other heat receiving surface 107 b of the heat sink 107. The side wall of the heat sink 107 having the heat receiving surfaces 107a and 107b is coupled to the heat radiating fins. The conventional heat sink 51 has a height L1, and the heat sink 107 according to the present embodiment has a height L2 (L2 <L1). The conduction path cover 111 is disposed in a range corresponding to the heat receiving surface 107a. The heat sink 107 and the heat sink 51 have the same configuration except for the height.

  When the height of the conduction path 157 is L3, the relationship is L1 = L2 + L3. That is, the heat dissipation device 100 and the heat dissipation device 50 have the same housing height. The conduction path 157 is formed in the same height in a slit shape over the entire width direction of the heat sink 107 or the direction perpendicular to the plane of the heat radiation fin. In order to supplement mechanical strength, the conduction path cover 111 may be partially supported from the heat receiving surface 107a. The height L1 of the conventional heat sink 51 is 17 mm, for example. The height L2 of the heat sink 107 according to the present embodiment is 16 mm, for example, and at this time, the height of the conduction path 157 is 1 mm. In addition, although the figure has shown the example which provided the conduction path 157 only about the heat sink 107, you may make it provide the conduction path similarly about the heat sink 105 with a conduction path cover.

  In the heat dissipation device 100, when the heat dissipation fan 101 rotates, the air flowing into the air chamber 110 from the intake ports 153 and 155 is exhausted outside the system housing 15 through the heat sink 107 and the exhaust port 16. In the heat radiating device 100, some air is exhausted through the conduction path 157, but in the heat radiating device 50, the air is exhausted only through the heat sink 51.

  FIG. 5 is a diagram for explaining the heat dissipation capability of the heat dissipation device 100 in comparison with the heat dissipation device 50 by experiments. In the experiment, for the heat dissipation devices 100 and 50, the same heat load was applied with the rotational speed of the heat dissipation fan 101 kept constant at 3300 rpm, the height L2 of the heat sink 107 was changed, and the flow rates of the heat sinks 107 and 51 and the temperatures at various places. Was measured. The horizontal axis in FIG. 5 indicates that the height L3 of the conduction path 157 is changed in four stages of 2.0 mm, 1.5 mm, 1.0 mm, and 0.5 mm. Further, for the heat sink 51, the height L3 of the conduction path 157 is indicated by 0 mm.

  A line 201 indicates the temperature of the heat receiving surfaces 107b and 51b, a line 203 indicates the temperature at the position B on the bottom surface 22, and a line 205 indicates the temperature at the position C on the keyboard edge frame 14. Lines 207 and 209 indicate the wind speed at the outlets of the heat sinks 107 and 51. A line 207 shows the wind speed at the center position in the height direction and the width direction of the heat sinks 107 and 51, and a line 209 shows the wind speed at the center position in the width direction and the wind direction at a position near the conduction path 157. Yes.

  As can be seen from FIG. 5, the temperature of the heat receiving surface 107b is lower than that of the heat receiving surface 51b (line 201), and the temperature at the position B of the bottom surface 22 is lower when the heat dissipation device 100 is mounted than when the heat dissipation device 50 is mounted. (Line 203). The temperature at the position C of the keyboard edge frame 14 is slightly lower when the heat dissipation device 50 is mounted than when the heat dissipation device 100 is mounted (line 205). However, such a temperature rise is not a substantial problem, and can be solved by shifting the heat dissipating device 100 as a whole downward. As for the wind speed, there is no difference between the heat sinks 107 and 51 in the central position in the height direction (line 207), but a significant difference appears in the vicinity of the conduction path 157 (line 209). In the heat dissipation device 100, the temperature of the heat receiving surface 107b is lower than that of the heat dissipation device 50. Therefore, the CPU temperature can be lower than that of the heat dissipation device 50, and the temperature of the bottom surface 22 can also be lower. .

  FIG. 5 shows that the heat radiation capability is highest when the height L3 of the conduction path 157 is 1.0 mm. This height of 1.0 mm corresponds to the pitch of the radiation fins. It can also be seen that the heat dissipation device 100 has a higher heat dissipation capability than the heat dissipation device 50 in the entire range of 0.5 mm to 2.0 mm. When the height L3 of the conduction path 157 is 0.5 mm, the height L2 of the heat sink 107 is 16.5 mm, and the ratio of the height of the conduction path 157 to the height of the heat sink 107 is 3%. It is. When the height L3 of the conduction path 157 is 2.0 mm, the height L2 of the heat sink is 15 mm, and the ratio of the height of the conduction path 157 to the height of the heat sink 107 is 13%. .

  That is, the heat radiating device 100 can improve the heat radiating capability as compared with the heat radiating device 50 having the same height by forming a conduction path having a height ranging from 3% to 13% of the height of the heat sink. Further, when the heat dissipation device 100 has the same heat dissipation capability as that of the heat dissipation device 50, the rotational speed of the heat dissipation fan 101 can be reduced, so that noise and power consumption can be reduced. Furthermore, when it is set as the same heat radiation capability, the height of the heat radiating device 100 can be further lowered to reduce the size.

  The reason why the heat dissipating device 100 has an improved heat dissipating capacity with respect to the heat dissipating device 50 despite the fact that the heat sink height is lower is considered as follows. When the dynamic pressure distribution in the air chamber 110 when the heat radiating fan 101 is rotated is analyzed by simulation, the heat radiating device 50 generates a large dynamic pressure at a position D in FIG. Shows that a large dynamic pressure is generated. Further, it can be seen that the air flow rate corresponding to the positions D and E of the heat sinks 107 and 105 does not increase the flow velocity to the extent corresponding to the high dynamic pressure.

  The reason for this is that a centrifugal radiating fan generates a large turbulent flow on the discharge side of the blade, and air is swirled at the entrance of the air flow path formed by the radiating fins, preventing smooth air passage. It is done. On the other hand, when the conductive path 157 is provided, the vortex is eliminated and air can smoothly enter the air flow path formed between the heat radiating fins. The flow velocity at the position of each air flow path in the vicinity of the conduction path 157 indicated by the range 140 is increased, and the thermal resistance of the radiating fin can be decreased. Furthermore, since the heat receiving surface 107a itself is radiated by the air passing through the conduction path 157, it contributes to the improvement of the heat capacity.

  The example in which the conduction path 157 is formed by the heat receiving surface 107a of the heat sink 107 and the conduction path cover 111 has been shown so far, but the present invention can also form the conduction path as a part of the heat sink. FIG. 7 is a diagram illustrating a heat sink having a conduction path. In the heat sink 301 of FIG. 7A, a conduction path 303 is formed between an inner wall 307 to which one end of a plurality of heat dissipating fins 309 is coupled and an outer wall 305 of the heat sink 301. The other ends of the plurality of radiating fins 309 are coupled to an outer wall including the heat receiving surface 311.

  The conduction path 303 is formed in a slit shape in a direction perpendicular to the surface of the heat radiation fin 309. The conduction path 303 may be formed as a complete slit-shaped opening, or the outer wall 305 and the inner wall 303 may be partially coupled for the purpose of reinforcement. Heat pipes 313 and 315 are coupled to the heat receiving surface 311 below the heat sink 301. The heat received by the heat pipes 313 and 315 is transferred to the air through the plurality of heat radiation fins 309. In the heat sink 301, the passage of air through each air flow path indicated by the range 310 in the vicinity of the conduction path 303 is smooth, and the heat dissipation capability is improved.

  In the heat sink 351 of FIG. 7B, a plurality of heat radiation fins 361 are coupled between the outer wall having the heat receiving surface 359 and the inner wall 355, and the plurality of fins 363 are between the outer wall having the heat receiving surface 365 and the inner wall 357. Is bound to. The conduction path 353 is formed in a slit shape between the inner wall 355 and the inner wall 357 in a direction perpendicular to the surfaces of the radiation fins 361 and 363. A heat pipe 367 is coupled to the heat receiving surface 359, and a heat pipe 369 is coupled to the heat receiving surface 365.

  The heat received by the heat receiving surface 359 from the heat pipe 367 is transmitted to the air through the heat radiation fins 361, and the heat received by the heat pipe 369 is transmitted to the air through the heat radiation fins 363. The position of the conduction path 353 in the height direction can be determined so that the height of the heat radiation fin coupled to the heat receiving surface that becomes higher in temperature is increased. In the heat sink 351, the passage of air in each air flow path indicated by the range 360 in the vicinity of the conduction path 353 is smoothed, and the heat dissipation capability is improved.

  Although the present invention has been described with the specific embodiments shown in the drawings, the present invention is not limited to the embodiments shown in the drawings, and is known so far as long as the effects of the present invention are achieved. It goes without saying that any configuration can be adopted.

10 ... Notebook PC
DESCRIPTION OF SYMBOLS 15 ... System housing | casing 100 ... Radiating device 101 ... Radiating fan 105, 107, 301, 351 ... Heat sink 109 ... Fan cover 110 ... Air chamber 111 ... Conduction path cover 125, 127, 129, 313, 315, 367, 369 ... Heat pipe 151 ... Housing 309, 361, 363 ... Radiation fin

Claims (10)

A centrifugal fan housed in an air chamber;
A heat sink comprising a plurality of heat dissipating fins disposed around the centrifugal fan and coupled to the first side wall and the second side wall to form a plurality of air flow paths;
A conduction path cover constituting the air chamber disposed so as to form a conduction path extending in a slit shape in a direction perpendicular to the surfaces of the plurality of radiation fins between the first side wall and the first side wall ; Have
A heat radiating device in which air pressurized by the centrifugal fan is exhausted through the plurality of air flow paths and the conduction path. The heat dissipation device according to claim 1 , wherein a heat pipe is coupled to the second side wall. The heat radiating device according to claim 1 , wherein a distance between the heat radiating fins and a height of the conduction path are substantially equal. The heat dissipation device according to any one of claims 1 to 3 , wherein a height of the conduction path is not less than 3% and not more than 13% of a height of the heat sink. A system enclosure;
An electronic device that generates heat inside the system housing;
An electronic apparatus comprising the heat dissipation device according to any one of claims 1 to 4 . The electronic device includes a processor;
6. The electronic device of claim 5 , comprising a heat pipe coupled to the processor and the heat sink. A heat sink used in combination with a centrifugal fan housed in an air chamber ,
A first sidewall;
A second sidewall;
The inner wall ,
A plurality of radiating fins coupled to the first side wall and the inner wall so as to form a plurality of air flow paths;
The inner wall and the second side wall form a conduction path extending in a slit shape in a direction perpendicular to the surface of the radiation fin, and the air pressurized by the centrifugal fan is A heat sink capable of passing through a conduction path. A heat sink used in combination with a centrifugal fan housed in an air chamber,
  A first sidewall;
  A first inner wall;
  A plurality of first radiating fins coupled to the first side wall and the first inner wall to form a plurality of air flow paths;
  A second sidewall;
  A second inner wall;
  A plurality of second radiating fins coupled to the second inner wall and the second side wall to form a plurality of air flow paths;
  The first and second inner walls form a conductive path extending in a slit shape in a direction perpendicular to the surfaces of the first and second radiating fins, and the centrifugal fan A heat sink capable of passing the air pressurized by the plurality of air flow paths and the conduction path. A centrifugal fan housed in an air chamber;
  A heat sink according to claim 7 or claim 8,
  A heat radiating device in which air pressurized by the centrifugal fan is exhausted through the plurality of air flow paths and the conduction path. A system enclosure;
  An electronic device that generates heat inside the system housing;
  A heat dissipation device according to claim 9 and
Electronic equipment having

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