JP4697307B2 - Cooling device, electronic device and blower - Google Patents

Description

  The present invention relates to a blower that generates an air flow toward a heat sink, a cooling device that includes the heat sink and the blower, and an electronic device on which the cooling device is mounted.

  2. Description of the Related Art Conventionally, with an increase in performance of a PC (Personal Computer), an increase in the amount of heat generated from a heat source such as a CPU has been a problem, and various heat dissipation techniques have been proposed or commercialized. As a heat dissipation method, heat from the CPU is conducted to a heat sink having a heat dissipation fin made of metal such as aluminum and the heat is released from the heat dissipation fin, and the fan device forcibly warms the air around the heat dissipation fin. Methods to eliminate are known.

  However, since the fan device takes in the air around the fan device from the intake port and blows an air flow to the heat sink fin of the heat sink, dust such as dust and dust contained in the air is blown to the heat sink fin at the same time. As a result, there is a problem that dust adheres and accumulates between the heat radiating fins, and the cooling performance of the heat sink is deteriorated.

  As a technique related to such a problem, the following Patent Document 1 includes a heat sink that has an inclined portion on an end surface on a side to which an air flow generated by rotation of a blade portion is blown and is formed in a trapezoidal shape. A cooling device is disclosed. The duct that restricts the airflow generated by the blades in one direction is provided with a dust exhaust port in addition to the intake port and the exhaust port. The dust contained in the air flow moves along the inclined portion of the heat sink and is discharged to the outside from the dust exhaust port formed in the duct.

  Further, as a technique related to the above problem, for example, Patent Document 2 below discloses a cooling device including a heat sink formed separately into a first heat sink and a second heat sink. The second heat sink, which is close to the air blowing port of the cooling fan and easily adheres to dust, is detachable from an electronic device such as a PC. The user removes the second heat sink from the PC and cleans it, and removes accumulated dust from the second heat sink.

Japanese Patent Laying-Open No. 2005-321287 (paragraphs [0035], [0050], [0062], [0063] FIG. 1) JP 2008-159925 A (paragraphs [0036], [0042] to [0045] FIGS. 3 and 4)

  However, the cooling device described in Patent Document 1 can reduce the amount of dust adhering to the heat sink, but it is not sufficient as a dust countermeasure. That is, if a PC is used for a long period of time, dust will eventually accumulate between the radiation fins.

  On the other hand, in the cooling device described in Patent Document 2, the second heat sink can be removed from the PC and cleaned. However, with this cooling device, the user must remove the second heat sink from the PC, which is troublesome.

  In view of the circumstances as described above, an object of the present invention is to provide a blower capable of automatically removing dust adhering to a heat sink, a cooling device including the blower and the heat sink, and an electric device equipped with the cooling device. It is to provide.

In order to achieve the above object, a cooling device according to an embodiment of the present invention includes a heat sink, a blade member, a flow path member, a limiting member, and a drive mechanism.
The heat sink has a surface on which airflow is blown.
The blade member generates the airflow toward the surface.
The flow path member forms a flow path for guiding the airflow from the blade member to the heat sink.
The restriction member can restrict the flow path.
The drive mechanism switches between a first state in which the restriction member does not restrict the flow path and a second state in which the restriction member restricts the flow path and a vortex is generated so as to contact the surface. Thus, the restricting member is driven.
In the present invention, in the first state, the restricting member does not restrict the flow path, and the flow path is open. In this case, the airflow generated by the blade member is blown to the heat sink, and the heat sink is cooled (cooling mode).
On the other hand, in the second state, the restricting member restricts the flow path. In this case, the airflow passing through the flow path is changed, and a vortex is generated so as to contact the heat sink. By this eddy current, dust adhered to and deposited on the heat sink can be peeled off from the heat sink and removed (dust removal mode).
In the present invention, the first state (cooling mode) and the second state (dust removal mode) can be automatically switched by the drive mechanism. Thereby, the troublesomeness which removes and heat-cleans a heat sink from electronic device main bodies, such as PC, can be eliminated.

The cooling device may further include control means for controlling the drive mechanism so as to periodically switch the first state to the second state.
In the present invention, since the first state (cooling mode) is periodically switched to the second state (dust removal mode), dust adhering to the heat sink accumulates and becomes clogged between the radiation fins. In addition, dust can be removed from the heat sink.

In the cooling device, the blade member may generate the airflow by rotation.
In this case, the control means may control the drive mechanism so as to switch the first state to the second state when rotation of the stopped blade member is started.
Thereby, dust adhering to the heat sink is accumulated and can be removed from the heat sink before being clogged between the radiating fins.

In the cooling device, when the blade member generates the airflow by rotation, the control means switches the first state to the second state when the rotation of the blade member is stopped. The drive mechanism may be controlled.
Thereby, dust adhering to the heat sink is accumulated and can be removed from the heat sink before being clogged between the radiating fins.

In the cooling device, when the blade member generates the airflow by rotation, the cooling device may further include a rotation number counting unit and a rotation number determination unit.
The rotation number counting means counts the rotation number of the blade member.
The rotation speed determination means determines whether or not the counted rotation speed has reached a specified number.
In this case, the control means may control the drive mechanism so as to switch the first state to the second state when the rotational speed reaches the specified number.
Thereby, dust adhering to the heat sink is accumulated and can be removed from the heat sink before being clogged between the radiating fins.

The cooling device may further include a time count unit and a time determination unit.
The time counting means counts a time from when the second state is switched to the first state.
The time determination means determines whether or not the counted time has reached a specified time.
In this case, the control means may control the drive mechanism so that the first state is switched to the second state when the time reaches a specified time.
Thereby, dust adhering to the heat sink is accumulated and can be removed from the heat sink before being clogged between the radiating fins.

An electronic device according to one embodiment of the present invention includes a heat source and a cooling device.
The cooling device includes a heat sink, a blade member, a flow path member, a limiting member, and a drive mechanism.
The heat sink has a surface on which an air current is blown, and releases heat from the heat source.
The blade member generates the airflow toward the surface.
The flow path member forms a flow path for guiding the airflow from the blade member to the heat sink.
The restriction member can restrict the flow path.
The drive mechanism switches between a first state in which the restriction member does not restrict the flow path and a second state in which the restriction member restricts the flow path and a vortex is generated so as to contact the surface. Thus, the restricting member is driven.

The blower mechanism according to the present invention includes a blade member, a flow path member, a limiting member, and a drive mechanism.
The blade member generates the airflow toward the surface of a heat sink having a surface to which the airflow is blown.
The flow path member forms a flow path for guiding the airflow from the blade member to the heat sink.
The restriction member can restrict the flow path.
The drive mechanism switches between a first state in which the restriction member does not restrict the flow path and a second state in which the restriction member restricts the flow path and a vortex is generated so as to contact the surface. Thus, the restricting member is driven.

  As described above, according to the present invention, it is possible to provide an air blower capable of automatically removing dust attached to a heat sink, a cooling device including the air blower and the heat sink, and an electric device equipped with the cooling device. Can do.

It is a perspective view which shows the electronic device by which the cooling device which concerns on one Embodiment of this invention is mounted. It is a perspective view which shows the cooling device which concerns on one Embodiment of this invention. It is a disassembled perspective view which shows the cooling device which concerns on one Embodiment of this invention. It is side sectional drawing of the cooling device which concerns on one Embodiment of this invention. It is a schematic diagram for demonstrating operation | movement of the cooling device which concerns on one Embodiment of this invention. It is a figure which shows a mode that dust adhered to the heat sink. It is an enlarged view which shows the heat sink to which dust adhered. It is a figure which shows the relationship between the generation | occurrence | production area | region of a secondary vortex, and various parameters. It is a figure for demonstrating the relationship between the expansion rate of a flow path, and the magnitude | size of a secondary vortex, and is a model figure of an expansion flow. And reattachment distance _{x R} and the ratio _x R / _{b 0} interval _{b 0} of the slit is a diagram showing a relationship between enlargement ratio D / _{b 0} to graphically. It is a figure which shows the apparatus for a test used in order to evaluate dust removal performance. It is the figure which compared the flow path resistance of the heat sink when it has dust removal performance before a test, and when it does not have dust removal performance. It is a flowchart which shows operation | movement of one Embodiment regarding the switching timing of a mode. It is a flowchart which shows operation | movement of other embodiment regarding the switching timing of a mode. It is a flowchart which shows operation | movement of another embodiment about the switching timing of a mode. It is a flowchart which shows operation | movement of another embodiment about the switching timing of a mode.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a perspective view showing an electronic apparatus equipped with a cooling device according to this embodiment. In the description of the present embodiment, a notebook PC will be described as an example of an electronic device on which a cooling device is mounted. Moreover, in each figure demonstrated below, in order to display drawing easily, it may display different from an actual dimension.

  As shown in FIG. 1, the notebook PC 101 includes an upper housing 91, a lower housing 92, and a hinge portion 93 that rotatably connects the upper housing 91 and the lower housing 92. The upper housing 91 includes a display unit 94 such as a liquid crystal display or an EL (Electro-Luminescence) display.

  The lower housing 92 has a plurality of input keys 95 and a touch pad 96 on the upper surface 92a. Further, the lower housing 92 has an exhaust port 97 on the side surface 92b, and an intake port (not shown) on the bottom surface 93c.

  The lower housing 92 has a control circuit board (not shown) on which electronic circuit components such as a CPU are mounted.

  The cooling device 100 is disposed inside the lower housing 92 so as to be close to the exhaust port 97.

  FIG. 2 is a perspective view showing the cooling device according to the present embodiment, and FIG. 3 is an exploded perspective view of the cooling device. FIG. 4 is a side sectional view of the cooling device.

  As shown in these drawings, the cooling device 100 according to the first embodiment of the present invention includes a heat sink 60 and a blower device 50 that generates an airflow toward the heat sink 60.

The heat sink 60 has a rectangular parallelepiped shape that is long in one direction (x-axis direction), and is formed with a predetermined width W ₁ (x-axis direction) and a predetermined height H ₁ (z-axis direction). The heat sink 60 includes a plurality of radiating fins 61 and an upper plate member 62 and a lower plate member 63 that support the radiating fins 61 above and below, respectively. The radiating fins 61 are arranged along the longitudinal direction (x-axis direction) of the heat sink 60 so as to be arranged at a predetermined interval. The airflow generated by the blower 50 passes between the heat radiation fins 61. The heat sink 60 is formed of, for example, a metal such as aluminum or copper, but the material is not particularly limited.

  In addition, the surface which opposes the blade member 10 among each surface which the heat sink 60 has is called the opposing surface 60a.

  In the heat sink 60, for example, the upper plate member 62 is thermally connected to the heat pipe 70. The heat pipe 70 is thermally connected to a heat source such as a CPU of the notebook PC 101 via the heat spreader 80, for example. The heat generated by the CPU is received and diffused by the heat spreader 80 and transmitted to the heat sink 60 via the heat pipe 70.

  A thermal connection method between the heat sink 60 and a heat source such as a CPU is not particularly limited. For example, the heat sink 60 may be disposed so as to directly contact the heat spreader 80 without using the heat pipe 70.

  The blower device 50 includes a rotatable blade member 10, a fan case 20 that houses the blade member 10, and a fan drive motor 15 that rotationally drives the blade member 10. The blower 50 includes a rotating member (restricting member) 30 provided between the blade member 10 and the heat sink 60, and a drive mechanism 40 that drives the rotating member 30.

  The blade member 10 is a centrifugal blade member 10 and includes a boss portion 11 and a plurality of blade portions 12 provided so as to extend from the boss portion 11 in the centrifugal direction. The blade member 10 is rotatable about the axis in the z-axis direction, and is rotated counterclockwise by the fan driving motor 15. By the rotation of the blade member 10, an air flow is generated toward the heat sink 60.

  The fan drive motor 15 includes, for example, a stator, a magnet, and a rotor yoke (not shown). The fan driving motor 15 is electrically connected to, for example, a CPU of the notebook PC 101, and driving and stopping are controlled by the CPU.

  The fan case 20 is formed by, for example, a case body 21 that forms the side peripheral portion 20b and the lower portion 20c of the fan case 20, and a lid member 22 that forms the upper portion 20a of the fan case 20.

  An upper air inlet 23 and a lower air inlet 24 are provided in the upper part 20a and the lower part 20c of the fan case 20, respectively. The upper air inlet 23 and the lower air inlet 24 are provided near the center of the upper part 20a and the lower part 20c of the fan case 20, respectively.

  The fan case 20 has a function as a flow path for guiding the airflow generated by the blade member 10 to the heat sink 60 in addition to the function of housing the blade member 10. Hereinafter, an area between the blade member 10 and the heat sink 60 and mainly having a function as a flow path of the airflow is referred to as a flow path area 20P (see FIG. 4) of the fan case 20. Further, in the flow path region 20P, the direction in which the airflow is directed is referred to as a flow path direction.

The flow path 26 in the flow path region 20P is a rectangular flow path, and the width W ₂ and the height H ₂ of the flow path 26 are substantially equal in the flow path direction (y-axis direction) (flow path Cross-sectional area = W ₂ × H ₂ ). Width _{W 2} and a height _{H 2} of the flow channel 26 is set relative width _{W 1} and a height _{H 1} of the heat sink 60, the width _{W 2} and a height _{H 2} of the flow channel 26, Each is substantially the same as the width W ₁ and the height H _{1 of the} heat sink 60. As a result, the airflow that has passed through the flow path 26 is blown over the entire heat sink 60.

  The rotating member 30 is disposed between the blade member 10 and the heat sink 60 inside the fan case 20. That is, the rotation member 30 is disposed in the flow path region 20P of the fan case 20.

The rotating member 30 has a rectangular thin plate shape that is long in one direction (x-axis direction), and the width W ₃ of the rotating member 30 is substantially equal to the width W _{2 of the} flow path 26. The details of the height H ₃ of the rotating member 30 will be described later. The rotating member 30 is formed of, for example, resin or metal, but the material is not particularly limited.

  The drive mechanism 40 drives the support shaft 41 connected to the rotating member 30, the arm portion 42 connected to one end of the support shaft 41, the spring 43 connected to the arm portion 42, and the arm portion 42. A solenoid 44.

  The support shaft 41 is disposed along the x-axis direction below the flow channel region 20P, and is rotatable below the flow channel region 20P. The support shaft 41 is connected to one end of the rotating member 30 in the short direction. Thereby, the rotation member 30 can be rotated around the support shaft 41 in the flow path region 20P.

  The arm portion 42 is connected to one end portion of the support shaft 41 through a hole provided in the side peripheral portion 20 b of the fan case 20.

  One end portion of the spring 43 is connected to a spring support portion 45 provided on the side peripheral portion 20 b of the fan case 20, and the other end portion of the spring 43 is connected to the arm portion 42.

  The solenoid 44 is electrically connected to the CPU of the notebook PC 101, for example, and drives the support shaft 41 and the rotating member 30 via the arm portion 42 under the control of the CPU.

[Description of operation]
Next, the operation of the cooling device 100 will be described. FIG. 5 is a schematic diagram for explaining the operation of the cooling device 100. FIG. 5A is a schematic diagram showing a state in which the rotating member 30 is tilted, and FIG. 5B is a diagram in which the rotating member 30 is raised at a predetermined angle with respect to the flow path direction. It is a schematic diagram which shows a state.

  First, with reference to FIG. 5 (A), the operation in a state where the rotating member 30 is tilted will be described.

  As shown in FIG. 5A, the rotating member 30 is normally tilted in a state parallel to the airflow, and is stopped in this state. That is, the rotating member 30 is stopped without restricting the flow path 26.

  For example, when the driving of the fan driving motor 15 is started under the control of the CPU, the rotation of the blade member 10 is started. When the rotation of the blade member 10 is started, the air inside the lower housing 92 of the notebook PC 101 is sucked into the fan case 20 through the upper air inlet 23 and the lower air inlet 24.

  Air sucked into the fan case 20 is accelerated in the centrifugal direction by the blade member 10, and an airflow is generated toward the heat sink 60. The airflow generated by the blade member 10 passes through the flow path 26 and is blown onto the facing surface 60 a of the heat sink 60.

  The heat sink 60 radiates heat from a heat source such as a CPU from the heat radiating fins 61 via the heat spreader 80 and the heat pipe. The warm air between the radiation fins 61 is exhausted to the outside of the notebook PC 101 through the exhaust port 97 of the notebook PC 101 by the air flow generated by the blade member 10. Thereby, the CPU and the heat sink 60 are cooled.

  In the present specification, the state in which the rotating member 30 does not limit the flow path, the flow path 26 is open, and the heat sink 60 is cooled is referred to as a cooling mode.

  Here, the air inside the lower housing 92 sucked from the upper air inlet 23 and the lower air inlet 24 contains dust such as dust and dirt. Therefore, dust is also contained in the airflow blown to the heat sink 60. As a result, dust such as dust and dirt adheres to and accumulates on the heat sink 60.

  FIG. 6 is a diagram illustrating a state in which dust adheres to the heat sink. FIG. 7 is an enlarged view showing a heat sink to which dust is attached.

  If the cooling mode is continued for a long period of time, dust is clogged between the radiation fins 61 as shown in FIGS. Most of the dust that adheres to and accumulates on the heat sink 60 is thread-like dust. This thread-like dust is particularly likely to adhere and accumulate on the facing surface 60 a of the heat sink 60.

  If the state in which dust adheres and accumulates on the heat sink 60 is left, the air permeability of the radiating fins 61 is hindered, and the cooling performance of the cooling device 100 deteriorates.

  Next, with reference to FIG. 5 (B), the operation when the rotating member 30 is raised at a predetermined angle with respect to the flow path direction will be described.

  For example, when the solenoid 44 is driven under the control of the CPU, the rotating member 30 is rotated about the support shaft 41 as a central axis. In this case, for example, the rotating member 30 is stopped for several seconds or several minutes in a state of being inclined by 90 ° with respect to the flow path direction.

  When the rotating member 30 is rotated and the air flow channel 26 is locally narrowed (hereinafter, narrow channel 27), the air flow is changed, and a secondary vortex is generated on the right side of the rotating member 30. That is, when the airflow moves from a narrow flow path to a wide flow path, secondary vortices are generated due to the relationship between the expansion ratios of the flow paths. The cooling device 100 according to the present embodiment uses secondary vortices generated due to the relationship between the expansion ratios of the flow paths.

  When the rotating member 30 restricts the flow path 26 and a secondary vortex is generated, dust attached to the facing surface 60a of the heat sink 60 is peeled off by the secondary vortex. The dust peeled off by the secondary vortex is caught in the secondary vortex and then released from between the heat radiating fins 61 and is released to the outside of the notebook PC 101 through the exhaust port 97 of the notebook PC 101.

  In the present specification, the state in which the rotating member 30 restricts the flow path 26 and a secondary vortex is generated and dust is removed is referred to as a dust removal mode.

  As described above, the cooling device 100 according to the present embodiment can strongly remove dust attached to the facing surface 60a of the heat sink 60 by the secondary vortex in the dust removal mode. Thereby, it can prevent that the cooling performance of the cooling device 100 falls.

  Furthermore, since the switching between the cooling mode and the dust grading mode is controlled by the CPU, the cooling device 100 according to the present embodiment can automatically switch between the cooling mode and the dust removal mode. Thereby, since the dust adhering to the heat sink 60 can be automatically removed, the troublesomeness of removing the heat sink 60 from the notebook PC 101 for cleaning can be eliminated.

  Furthermore, in the present embodiment, dust such as dust and dust can be removed from the heat sink 60 without increasing the rotational speed of the blade member 10. Thereby, the excessive raise of the power consumption of the cooling device 100 can be suppressed. Further, even when the power of the fan driving motor 15 that rotates the blade member 10 is small and it is difficult to generate a strong wind, dust can be removed from the heat sink 60.

  In the description of FIG. 5B, it has been described that in the dust removal mode, the rotating member 30 is stopped in a state inclined by 90 ° with respect to the flow path direction. However, the present invention is not limited to this, and the angle with the flow path 26 may be less than 90 ° or may exceed 90 °. That is, it is sufficient that the secondary eddy current is in contact with at least the opposing surface 60a of the heat sink in the dust removal mode, and the angle at which the rotating member 30 is raised is not particularly limited.

[Relationship between secondary vortex generation area and various parameters]
As described above, the cooling device 100 according to the present embodiment has an object of removing dust attached to the heat sink 60 by the secondary vortex generated by the rotating member 30. Therefore, various parameters are set so that at least the facing surface 60a of the heat sink 60 is disposed in the secondary vortex generation region. The various parameters include the height H ₂ of the flow path 26, the height H _{3 of} the rotating member 30, the angle φ at which the rotating member 30 is rotated, and the rotation member 30 and the opposed surface 60 a of the heat sink. The distance d, the interval a of the narrow flow path 27, and the like.

  FIG. 8 is a diagram showing the relationship between the secondary vortex generation region and the various parameters.

  FIG. 8A is a diagram showing the relationship between the secondary vortex generation region and various parameters when the rotating member 30 is rotated 90 ° (φ = 90 °). FIG. 8B is a diagram showing the relationship between the secondary vortex generation region and various parameters when the rotating member 30 is rotated 45 ° (φ = 45 °).

  Here, the relationship between the expansion ratio of the flow path and the size of the secondary vortex will be described.

  FIG. 9 is a diagram for explaining the relationship between the expansion rate of the flow path and the size of the secondary vortex, and is a model diagram of the expanded flow.

In FIG. 9, the slit interval is b ₀ , the height from the bottom surface to the slit is D, the reattachment distance is x _R , the attachment angle is θ, and the distance from the narrow channel outlet to the virtual origin is x ₀ . Has been. In FIG. 9, the redeposition streamline is represented by a broken line, and the coordinate system based on the central streamline is represented by the xy axis.

The attachment angle θ is expressed by the following equation (1) depending on the momentum equilibrium condition.
^{cosθ = 3t / 2-t 3} /2 ··· (1)

T shown in Formula (1) is represented by the following Formula (2).
t = tanh (σy ′ / (x + x ₀ )) (2)

  Here, in Equation (2), the diffusion coefficient is represented as σ, and the intersection of the y-axis and the reattachment streamline in the coordinate system with the central streamline as a reference is represented as y ′.

From the geometrical relationship, the enlargement ratio D / b ₀ is expressed by the following equation (3).
D / b ₀ = σ (1 / t ² −1) {(1-cos θ) / 3θ} −1/2 (3)

Furthermore, the ratio x _R / b ₀ between the reattachment distance x _R and the slit interval b ₀ is expressed by the following equation (4).
x _R / b ₀ = σ (1 / t ² −1) sin θ / 3θ-tanh ⁻¹ t / 3t ² sin θ (4)

Solving the simultaneous equations of formula (1) and (3), determine the t and θ as a function of the expansion ratio D / b _0, by substituting the equation (4), re-adhesion distance x _R and interval b of the slit the ratio _x R / _{b 0 0,} can be determined as a function of the expansion ratio D / _{b 0.}

In this case, an approximate expression indicating the relationship between the ratio x _R / b _{0 of the} reattachment distance x _R and the slit interval b ₀ and the enlargement ratio D / b ₀ is expressed by the following expression (5). .
_{x R / b 0 = 2.22 (} D / b 0) 0.636 + 0.780D / b 0 +0.939 ··· (5)

Figure 10 is a reattachment length _{x R} and the ratio _x R / _{b 0} interval _{b 0} of the slit is a diagram showing a relationship between enlargement ratio D / _{b 0} to graphically.

  In FIG. 10, diamond points represent numerical solutions obtained by actually solving the above equations (1), (3), and (4), and a solid line represents the approximate equation (5). Yes.

  In FIG. 10, the shaded area indicates the secondary vortex generation area.

Comparing FIG. 8A and FIG. 9, when the angle φ at which the rotating member 30 is rotated is 90 °, the height H ₃ of the rotating member 30 is the height D from the bottom surface to the slit. correspondingly, the distance a of the narrow channel 27 corresponds to the spacing b ₀ of the slit. In this case, it is considered that D shown in FIG. 10 is replaced with H ₃ and b ₀ is replaced with a, and the height H ₃ of the rotating member 30 and the narrow flow are taken so as to take values within the shaded area shown in FIG. Various parameters such as the distance a of the path 27 and the distance d between the rotating member 30 and the opposed surface 60a of the heat sink are set.

8B is compared with FIG. 9, when the rotation angle of the rotation member 30 is 45 °, the sine component H ₃ sinφ (φ = 45) of the height H ₃ of the rotation member 30. °) is, corresponds to the height D from the bottom surface to the slit, the distance a of the narrow channel 27 corresponds to the spacing b ₀ of the slit. In this case, it is assumed that D shown in FIG. 10 is replaced with H ₃ sin 45 ° and b ₀ is replaced with a, and the height H ₃ of the rotating member 30 is set so as to take a value within the shaded area shown in FIG. Various parameters such as the distance a between the narrow flow paths 27 and the distance d between the rotating member 30 and the opposed surface 60a of the heat sink are set.

  Thereby, since the opposing surface 60a of the heat sink 60 is arrange | positioned in the generation | occurrence | production area | region of a secondary vortex, the dust adhering to and deposited on the opposing surface 60a of the heat sink 60 can be removed appropriately.

[Evaluation of dust removal performance]
Next, the dust removal performance of the cooling device 100 will be described in more detail.

  FIG. 11 is a diagram showing a test apparatus used for evaluating dust removal performance.

  As shown in FIG. 11, the test apparatus 81 includes a test apparatus main body 82 having a hollow inside, and two sirocco fans 83 provided inside the test apparatus main body 82. The test apparatus main body 82 had a width, height, and depth of 300 mm × 300 mm × 300 mm, respectively. The two sirocco fans 83 are provided so as to face the side walls of the test apparatus main body 82, respectively.

  Inside the test apparatus main body 82, a cotton 85 that looks like dust and a cooling device 100 are arranged. A net 84 is hung on the cooling device 100 so as to cover the cooling device 100 in order to prevent a large lump of dust from entering.

  First, the sirocco fan 83 is driven for 30 seconds while the blade member 10 of the cooling device 100 is rotated (step 1).

  Next, after the rotation member 30 is rotated to an angle of 45 ° with respect to the flow path direction and held for 10 seconds, the rotation member 30 is returned to a position of 0 ° with respect to the flow path direction, Hold for 10 seconds. This operation is repeated twice (step 2).

  Thereafter, step 1 and step 2 are repeated 10 times.

  In the cooling device used for comparison (cooling device having no removal performance), in step 2, the rotating member 30 is not rotated and the rotating member 30 is 0 with respect to the flow path direction. Continued to hold at an angle of °.

  FIG. 12 is a diagram comparing the flow path resistances of the heat sink before and after the test when the dust removal performance is provided and when the dust removal performance is not provided.

In FIG. 12, the vertical axis represents the pressure difference ΔP (Pa) between the airflow before and after passing through the heat sink 60, and the horizontal axis represents the air volume Q (m ³ / min) of the airflow passing through the heat sink 60. Represents.

  In FIG. 12, the curve connecting the triangular points represents the channel resistance before the test, and the curve connecting the square points has dust removal performance, that is, the rotating member 30 was driven. In this case, the flow path resistance is shown. Further, the curve connecting the diamond points represents the channel resistance when the dust removal performance is not provided, that is, when the rotating member 30 is not driven.

In addition, the approximate expression of the curve when having dust removal performance before the test and not having dust removal performance shown in FIG. 12 is represented by the following expressions (6), (7), and (8), respectively. expressed.
ΔP = 4.82 × 10 ³ Q ² + 2.54 × 10 ² Q (6)
ΔP = 4.88 × 10 ³ Q ² + 2.62 × 10 ² Q (7)
ΔP = 7.71 × 10 ³ Q ² + 5.42 × 10 ² Q (8)

  As shown in FIG. 12, the flow path resistance of the heat sink 60 when it has dust removal performance is much lower than the flow path resistance of the heat sink 60 when it does not have dust removal performance. Furthermore, the flow path resistance of the heat sink 60 in the case of having dust removal performance hardly increases even when compared with the flow path resistance of the heat sink 60 before the test.

  From FIG. 12, it can be seen that the cooling device 100 according to the present embodiment is well removed of dust that becomes the flow path resistance of the heat sink 60. That is, it can be seen that the cooling device 100 according to the present embodiment has high dust removal performance.

  The present inventors actually observed the adhesion of dust between the heat sink 60 without dust removal performance and the heat sink 60 with dust removal performance. As a result, in the heat sink 60 having no dust removal performance, dust clogging between the heat radiating fins 61 is significant over the entire area of the opposing surface 60a, and a gap between the heat radiating fins is visible at a part of the center of the heat sink 60. It was about. On the other hand, in the heat sink 60 having dust removal performance, almost no dust adhered to the facing surface 60a, and a small amount of dust adhered to both sides of the heat sink.

(1st Embodiment about the switching timing of cooling mode and dust removal mode)
Next, a first embodiment regarding the switching timing of the cooling mode and the dust removal mode will be described.

  FIG. 13 is a flowchart showing the operation of the first embodiment regarding the mode switching timing.

  As shown in FIG. 13, for example, the CPU of the notebook PC determines whether or not a drive start signal for the fan drive motor 15 has been input (step 101). If the drive start signal has not been input (NO in step 101), the CPU again determines whether the drive start signal for the fan drive motor 15 has been input.

  When a drive start signal for the fan drive motor 15 is input (YES in step 101), the CPU starts driving the fan drive motor 15 (step 102). When driving of the fan driving motor is started, rotation of the blade member 10 is started and airflow is generated toward the heat sink 60.

  When the CPU starts driving the fan driving motor 15, the CPU next starts driving the solenoid 44 (step 103). When the solenoid 44 is driven, for example, the rotating member 30 is rotated to an angle of 45 ° with respect to the flow path direction. When the rotating member 30 is rotated, the flow path 26 is locally narrowed and a secondary vortex is generated. By this secondary vortex, the dust adhering to the facing surface 60a of the heat sink 60 is peeled off and removed (dust removal mode).

  The CPU stops driving the solenoid 44 after several seconds or minutes after the start of driving the solenoid 44 (step 104). When the drive of the solenoid 44 is stopped, the rotating member 30 is returned to an angle of 0 ° with respect to the flow path direction, and is in a state parallel to the airflow. In this case, the heat sink 60 is cooled (cooling mode).

  When the CPU stops driving the solenoid 44, the CPU returns to step 101 again and repeats the processing after step 101.

  By such processing, it is possible to periodically switch from the cooling mode to the dust removal mode. Thereby, the dust adhered to the heat sink 60 can be accumulated and removed from the heat sink before being clogged between the radiation fins.

(2nd Embodiment about the switching timing of cooling mode and dust removal mode)
Next, a second embodiment of the switching timing between the cooling mode and the dust removal mode will be described. FIG. 14 is a flowchart showing the operation.

  As shown in FIG. 14, the CPU determines whether or not a stop notice signal for the fan drive motor 15 has been input (step 201). When the stop warning signal is not input (NO in step 201), it is determined again whether the stop warning signal is input. In this case, the rotating member 30 is not rotated, and the heat sink 60 is cooled (cooling mode).

  When the stop notice signal is input (YES in step 201), the CPU does not immediately stop the fan drive motor 15 but starts driving the solenoid 44 (step 202). When the solenoid 44 is driven, the rotating member 30 is rotated and a secondary vortex is generated. Thereby, the dust adhering to the opposing surface 60a of the heat sink 60 is peeled off and removed (dust removal mode).

  The CPU stops driving the solenoid 44 after several seconds or minutes after the start of driving the solenoid 44 (step 203). When the drive of the solenoid 44 is stopped, the rotating member 30 is returned to an angle of 0 ° with respect to the flow path direction, and is in a state parallel to the airflow.

  After stopping the driving of the solenoid 44, the CPU stops the driving of the fan driving motor 15 (step 204).

  Even with such a process, dust can be periodically removed from the heat sink 60, so that the same effects as those of the first embodiment described above can be obtained.

(3rd Embodiment about the switching timing of cooling mode and dust removal mode)
Next, a third embodiment regarding the switching timing of the cooling mode and the dust removal mode will be described. FIG. 15 is a flowchart showing the operation.

  The CPU determines whether or not the drive of the solenoid 44 is stopped (step 301). That is, it is determined whether the dust removal mode is switched to the cooling mode and the cooling mode is started. When driving of the solenoid 44 is stopped (YES in step 301), the CPU turns on the counter timer and starts counting the count values generated at regular intervals. As the counter, a dedicated counter for the cooling device 100 may be used, or a counter mounted on an electronic device such as the notebook PC 101 may be used.

  Next, the CPU determines whether or not the count value has reached a specified value (step 303). This specified value is a specified value corresponding to a certain period of time, for example, a specified value corresponding to one week, but is not limited thereto.

  When the count value reaches the specified value (YES in step 303), that is, when a certain period (for example, one week) has elapsed since the start of the cooling mode, the fan driving motor 15 is driven at that time. It is determined whether or not (step 304).

  When the fan driving motor 15 is being driven (YES in step 304), the driving of the solenoid 44 is started (step 305). In this case, the rotating member 30 is rotated to generate a secondary vortex, and dust is removed from the facing surface 60a of the heat sink 60 (dust removal mode).

  The CPU stops driving the solenoid 44 after several seconds or minutes after the start of driving the solenoid 44 (step 306). In this case, the rotating member 30 is returned to an angle of 0 ° with respect to the flow path direction, and the heat sink 60 is cooled (cooling mode).

  On the other hand, if the fan drive motor 15 is not driven when the count value reaches the specified value (NO in step 304), the CPU determines whether or not a drive signal for the fan drive motor 15 is input. (Step 307).

  When the driving signal for the fan driving motor 15 is input (YES in Step 307), the CPU starts driving the solenoid 44 after driving the fan driving motor 15 (Step 308) (Step 305). That is, when the fan drive motor 15 is not driven when the count value reaches the specified value, the CPU waits until a drive signal for the fan drive motor 15 is input before driving the solenoid 44.

  When driving of the solenoid 44 is stopped (step 306), that is, when the cooling mode is started, the CPU resets the timer (step 302) and starts counting by the counter again.

  Also by such processing, it is possible to periodically switch from the cooling mode to the dust removal mode.

(4th Embodiment about the switching timing of cooling mode and dust removal mode)
Next, a fourth embodiment regarding the switching timing of the cooling mode and the dust removal mode will be described. FIG. 16 is a flowchart showing the operation.

  As shown in FIG. 16, the CPU determines whether or not the drive of the solenoid 44 is stopped (step 401), and determines whether or not the cooling mode is started.

  When driving of the solenoid 44 is stopped and the cooling mode is started (YES in step 401), the CPU inputs a rotation signal from the fan driving motor 15, and counts the number of rotations of the fan driving motor 15 by a counter. Is started (step 402).

  Next, the CPU determines whether or not the count value of the rotational speed has reached a specified value (step 403). The value corresponding to the specified value is, for example, 1 million times, but is not limited thereto.

  When the count value reaches a specified value (YES in step 403), that is, when the rotational speed of the blade member 10 reaches a specified number of times (for example, 1 million times), driving of the solenoid 44 is started (step 404). The rotating member 30 is rotated. Thereafter, the CPU stops driving the solenoid 44 (step 405), resets the rotation speed, and starts counting the rotation speed of the fan drive motor 15 again (step 402).

  Also by such processing, it is possible to periodically switch from the cooling mode to the dust removal mode.

[Variations]
Each embodiment described above can be variously modified.

  For example, an optical sensor or a magnetic sensor may be used to ensure control of the angle at which the rotating member 30 is rotated.

  In the above embodiments, the drive mechanism 40 that drives the rotating member 30 has been described as including the arm portion 42, the spring 43, and the solenoid 44. However, the configuration of the drive mechanism 40 is not limited to this. For example, the drive mechanism 40 that drives the rotating member 30 may be a motor. In this case, a stepping motor may be used to ensure control of the angle at which the rotating member 30 is rotated.

  In each of the above-described embodiments, it has been described that the driving of the fan driving motor 15 and the solenoid 44 is controlled by the CPU of the notebook PC. However, the present invention is not limited to this, and a CPU dedicated to the cooling device 100 may be provided, and driving of the fan driving motor 15 and the solenoid 44 may be controlled by this dedicated CPU.

  In the description of FIG. 1, the notebook PC 101 is given as an example of an electronic device on which the cooling device 100 is mounted, but the invention is not limited to this. Examples of the electronic device include a desktop PC, an audio / visual device, a projector, a game device, a robot device, and other electrical appliances.

DESCRIPTION OF SYMBOLS 10 ... Blade member 20 ... Fan case 30 ... Turning member 40 ... Drive mechanism 50 ... Air blower 60 ... Heat sink 60a ... Opposite surface 100 ... Cooling device 101 ... Notebook type PC

Claims (8)

A heat sink having a surface to which an air current is blown;
A blade member that generates the airflow by rotation toward the surface,
A flow path member that forms a flow path for guiding the air flow from the blade member to the heat sink;
A restricting member capable of restricting the flow path;
The restriction may be switched between a first state in which the restriction member does not restrict the flow path and a second state in which the restriction member restricts the flow path and a vortex is generated so as to contact the surface. A drive mechanism for driving the member;
A cooling device comprising: control means for controlling the drive mechanism so that the first state is switched to the second state when rotation of the stopped blade member is started . A heat sink having a surface to which an air current is blown;
A blade member that generates the airflow by rotation toward the surface,
A flow path member that forms a flow path for guiding the air flow from the blade member to the heat sink;
A restricting member capable of restricting the flow path;
The restriction may be switched between a first state in which the restriction member does not restrict the flow path and a second state in which the restriction member restricts the flow path and a vortex is generated so as to contact the surface. A drive mechanism for driving the member;
A cooling device comprising: control means for controlling the drive mechanism so as to switch the first state to the second state when the rotation of the rotating blade member is stopped . A heat sink having a surface to which an air current is blown;
A blade member that generates the airflow by rotation toward the surface,
A flow path member that forms a flow path for guiding the air flow from the blade member to the heat sink;
A restricting member capable of restricting the flow path;
The restriction may be switched between a first state in which the restriction member does not restrict the flow path and a second state in which the restriction member restricts the flow path and a vortex is generated so as to contact the surface. A drive mechanism for driving the member;
A rotation number counting means for counting the rotation number of the blade member;
A rotational speed determination means for determining whether or not the counted rotational speed has reached a specified number;
A cooling device comprising: control means for controlling the drive mechanism so as to switch the first state to the second state when the rotational speed reaches the prescribed number . A heat sink having a surface to which an air current is blown;
A blade member that generates the airflow toward the surface;
A flow path member that forms a flow path for guiding the air flow from the blade member to the heat sink;
A restricting member capable of restricting the flow path;
The restriction may be switched between a first state in which the restriction member does not restrict the flow path and a second state in which the restriction member restricts the flow path and a vortex is generated so as to contact the surface. A drive mechanism for driving the member;
Time counting means for counting a time since the second state is switched to the first state;
Time determination means for determining whether the counted time has reached a specified time;
A cooling device comprising: control means for controlling the drive mechanism so as to switch the first state to the second state when the time reaches a specified time . A heat source,
A heat sink that has a surface to which an air current is blown and that releases heat from the heat source; a blade member that generates the air flow by rotation toward the surface; A flow path member that forms a path; a restriction member that can restrict the flow path; a first state in which the restriction member does not restrict the flow path; and the restriction member restricts the flow path; When the rotation of the driving mechanism that drives the restricting member and the stopped blade member is started so as to switch between the second state where the vortex is generated so as to contact the first state, the first state is An electronic apparatus comprising: a cooling device having a control unit that controls the drive mechanism so as to switch to the second state . A heat source,
A heat sink that has a surface to which an air current is blown and that releases heat from the heat source; a blade member that generates the air flow by rotation toward the surface; A flow path member that forms a path; a restriction member that can restrict the flow path; a first state in which the restriction member does not restrict the flow path; and the restriction member restricts the flow path; When the rotation of the drive mechanism that drives the restricting member and the rotating blade member is stopped so as to switch between the second state where the vortex flow is generated so as to be in contact , the first state is An electronic apparatus comprising: a cooling device having control means for controlling the drive mechanism so as to switch to the second state . A blade member that generates the airflow by rotation toward the surface of the heat sink having a surface to which the airflow is blown,
A flow path member that forms a flow path for guiding the air flow from the blade member to the heat sink;
A restricting member capable of restricting the flow path;
The restriction may be switched between a first state in which the restriction member does not restrict the flow path and a second state in which the restriction member restricts the flow path and a vortex is generated so as to contact the surface. A drive mechanism for driving the member;
A blower comprising: control means for controlling the drive mechanism so that the first state is switched to the second state when rotation of the stopped blade member is started . A blade member that generates the airflow by rotation toward the surface of the heat sink having a surface to which the airflow is blown,
A flow path member that forms a flow path for guiding the air flow from the blade member to the heat sink;
A restricting member capable of restricting the flow path;
The restriction may be switched between a first state in which the restriction member does not restrict the flow path and a second state in which the restriction member restricts the flow path and a vortex is generated so as to contact the surface. A drive mechanism for driving the member;
A blower comprising: control means for controlling the drive mechanism so as to switch the first state to the second state when rotation of the rotating blade member is stopped .