JP2007247444A - Air blowing fan device and electronic equipment having this device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air blowing fan device and electronic equipment having this device, for reducing intake noise, by restraining generation of a turbulent flow by relieving a flow speed change in air in an edge part of an intake port, by reducing a flow speed of the air flowing toward the intake port along a fan casing. <P>SOLUTION: This air blowing fan device 1 has an air blowing fan 4 having a plurality of blade parts 4b, and the fan casing 2 rotatably storing the air blowing fan 4 and having at least one intake port. A shock absorbing member 9 is arranged on an outside surface of the fan casing 2 so as to surround the intake port 22a of the fan casing 2. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention is a blower fan device used for cooling a heat generating electronic component such as an ultra-compact processing unit (hereinafter referred to as MPU) mounted on a substrate inside an electronic device casing, and is thermally connected to the heat generating electronic component. The present invention relates to a blower fan device that forcibly blows and cools the heat of the heat radiating unit and an electronic device including the same.

  Recently, the speed of data processing in computers has been very rapid, and the clock frequency of MPU has become much higher than before.

  As a result, the amount of heat generated by the MPU is increased, and not only a conventional method of dissipating heat by directly contacting a heat sink having a heat radiation fin to a heat generating electronic component, but also a method of cooling the heat sink by directly blowing air with a blower fan, Alternatively, it is indispensable to configure a heat sink module in which the heat receiving part and the heat sink are thermally connected using a heat pipe, and forcibly blow the heat sink with a blower fan to dissipate the heat. Along with this improvement, it is necessary to reduce the thickness, weight and noise.

  In particular, a blower fan device mounted on a thin electronic device such as a mobile-compatible notebook PC has a thin flat fan casing because the space in the casing of the electronic device is extremely narrow in the height direction. An air blower fan is housed inside and an exhaust port is provided on at least one side thereof, and the air blower is located near a heat sink that has a plurality of heat dissipating fins and is thermally connected to a heat generating electronic component. In many cases, a fan device is installed and the heat sink is directly cooled by the air sent from the exhaust port of the air blowing fan device.

  FIG. 6 is a perspective view of a heat sink-integrated blower fan device described in the prior art (Patent Document 1).

  This blower fan device 100 is a module integrated with a heat sink, and the fan casing 101 is formed as a flat housing by aluminum die casting with good thermal conductivity and has blades inside. A blower fan 102 is rotatably provided with a motor, and an exhaust port 103 is provided on one side surface.

  In addition, the fan casing 101 is formed with a wind tunnel portion 104 for preventing a backflow connected to the exhaust port 103 outside the vicinity of the tip of the blade of the blower fan 102.

  When viewed from above, the wind tunnel portion 104 for preventing backflow is substantially continuous with an L shape along the exhaust port 103 side and the upstream side of the blower fan 102, and the fan casing 101. The inner height is larger than the fan chamber formed by

  Further, the heat receiving part 105 is connected to the outside of the fan casing 101, and a heat generating electronic component 106 such as an MPU is in contact with the heat receiving part 105. And the heat radiating fin part 107 which is a heat sink is joined to the exhaust port 103 side of the fan casing 101.

  In the heat sink-integrated blower fan device 100 configured as described above, the heat of the heat generating electronic component 106 is transmitted from the heat receiving part 105 to the heat radiating fin part 107 via the fan casing 101, and the heat radiating fan 102 transmits the heat radiating fin part 107. The heat exchange action can be effectively obtained by forced cooling.

  Therefore, even for a heat-generating electronic component 106 such as an MPU that is driven at a high frequency for image processing or the like and generates a high temperature, the temperature can be greatly reduced to prevent thermal destruction, and a small size and high airflow. For example, cooling useful for cooling a notebook PC or the like can be realized.

  On the other hand, FIG. 7 shows a partial sectional view in the axial direction of a centrifugal blower fan device described in Patent Document 2 which is a conventional technique.

  The sirocco fan-shaped centrifugal multiblade fan 201 of the centrifugal fan device 200 has a large number of blades 202 around the rotation shaft 200a and sucked from the other end side in the direction of the rotation shaft 200a. This is a centrifugal fan that blows air toward the radially outward side, and the electric motor 203 is a driving means that rotationally drives the multiblade fan 201.

  The casing 204 is a resin roll casing formed in a spiral shape that accommodates the multi-blade fan 201 and forms a flow path 204 a of air blown from the multi-blade fan 201. An air inlet 205 that opens toward one end in the direction of the rotation shaft 200a is formed.

  A bell mouth 206 that extends to the inner diameter edge D 1 of the multiblade fan 201 and covers the end of the blade 202 on the side of the intake port 205 is integrally formed in the casing 204 at the intake port 205.

  By the way, a shroud 207 in which a facing surface 207a facing the inner wall 204b of the casing 204 and having the first gap δ1 is formed on the intake port 205 side of the multiblade fan 201 is integrated with the blade 202 with resin. Molded.

  Note that the cross-sectional shape of the shroud 207 is the mainstream that circulates through the blade 202 so that the cross-sectional area of the air flow path decreases (the height of the blade decreases) from the inner diameter side to the outer diameter side of the multiblade fan 201. It is formed in a shape (substantially arc shape) along the streamline.

  Corresponding to the shroud 207, an extended portion 207b extending from the end portion on the intake port 205 side of the multi-blade fan 201 to one end side (upper side in the drawing) in the rotating shaft 200a is formed. The portion from the casing 204 to the upper surface of the casing 204 (the wall surface on the intake port 205 side) is formed such that a second gap δ2 continuous from the first gap δ1 is interposed between the extended portion 207b.

  The bell mouth 206 extends to the inner diameter edge D1 of the multiblade fan 201 to cover a part of the blade 202, and a first gap δ1 is formed between the shroud 207 and the inner wall 204b of the casing 204. Therefore, the flow path length of the flow path through which the backflow air from the first gap δ1 to the second gap δ2 flows can be increased.

  Therefore, since the pressure loss (ventilation resistance) of the flow path can be increased, it is possible to prevent the backflow air from increasing even if the ventilation resistance of the air conditioning casing is increased. As a result, since interference between the backflow air and the intake air can be suppressed, noise can be reduced while preventing a decrease in the amount of blown air.

Furthermore, although description using a figure is abbreviate | omitted, in patent document 3, the damper for air volume adjustment is provided in the bellmouth-shaped inlet of a ventilation fan apparatus, and the bellmouth shape is also provided in the inlet-side end surface. The structure which forms a part and suppresses the turbulent flow of the air in the inlet and reduces intake noise is disclosed.
JP 2003-69265 A (page 4, FIG. 1) Japanese Patent Laid-Open No. 11-280697 (page 6, FIG. 2) Japanese Utility Model Publication No. 61-202698 (FIGS. 1 and 2)

  However, the conventional blower fan device 100 such as (Patent Document 1) has a diameter slightly larger than the maximum outer diameter of the axial flow type blower fan 102 and has the same rotation center as that of the blower fan 102. The circular air inlet 108 is arranged on the upper surface of the fan casing 101, and the shape of the inner edge surrounding the air inlet 108 on the upper surface of the fan casing 101 is a flat shape over the entire outer peripheral area. ing.

  Therefore, the air flowing along the upper surface of the fan casing 101 and sucked into the intake port 108 flows along the inner edge surrounding the intake port 108, but the air flow direction and the flow velocity change rapidly, Since turbulent flow is also likely to occur, it has been a cause of increased intake noise.

  In particular, a casing of an electronic device that is mounted on an electronic device having a narrow space in the height direction, such as a notebook PC, and is disposed so as to face the outer surface of the fan casing 101 having the air inlet 108. When the gap with the wall, circuit board, or surrounding mounting member is about several millimeters or less, the flow velocity of the air flowing through the gap is increased, and most of the air sucked into the intake port 108 is in the inner edge portion. Although it flows along the vicinity, the flow direction changes greatly from the direction along the outer surface of the fan casing 101 to the direction of the rotation axis 109 of the blower fan 102 in the direction perpendicular to the direction, and turbulence is likely to occur. Intake noise was generated.

  On the other hand, in the conventional blower fan device 200 such as (Patent Document 2), although the bell mouth 206 is formed, a certain degree of turbulent flow suppression effect is expected from the gentle curved surface at the inner edge surrounding the air inlet 205, As described in (Patent Document 2), if the bell mouth 206 is enlarged over the entire outer peripheral region, the intake cross-sectional area may be reduced and the air flow rate may be reduced. A space between the outer surface of the casing 204 having the air inlet 205 and the casing wall, circuit board, or peripheral mounting member of the electronic device disposed so as to face the outer surface is narrow. Is about several millimeters or less, the flow velocity of the air flowing through the gap is increased, and most of the air sucked into the intake port 205 is in the vicinity of the inner edge, and the flow direction is Since it changes greatly in the direction perpendicular to the direction of the rotation axis 200a of the multi-blade fan 201 from the direction along the outer surface of the casing 204, turbulent flow is likely to occur. Therefore, the rotation of the multi-blade fan 201 is improved in order to improve the cooling performance. If the speed is further increased to increase the air volume, there is a problem that the effect of reducing the intake noise is not sufficient.

  Similarly, (Patent Document 3) has a problem of intake noise when it is arranged in a narrow space, and the noise of the blower fan device as described above is an HDD that does not generate sound normally (when not in use), Compared to driving noise such as FDD and CD-RW, since it is an irritating noise in addition to being continuously generated when the electronic device is used, it has been a problem to further reduce the noise.

  In order to solve the above-mentioned problem, the present invention is a blower fan device comprising a blower fan having a plurality of blades, a fan casing rotatably containing the blower fan and having at least one air inlet, The main feature is that a buffer member is provided on the outer surface of the fan casing so as to surround the air inlet of the fan casing.

  According to the present invention, there is provided a blower fan device comprising: a blower fan having a plurality of blades; and a fan casing that rotatably houses the blower fan and has at least one intake port, wherein the intake port of the fan casing By arranging a buffer member on the outer surface of the fan casing so as to surround the housing, the outer surface of the fan casing and the housing wall, circuit board, or peripheral mounting member of the electronic device arranged to face the outer surface of the fan casing , The cross-sectional area of the flow path of air flowing toward the intake port along the outer surface of the fan casing (area in the direction orthogonal to the ventilation direction) is reduced, and the pressure loss (ventilation resistance) is increased to increase the intake port. The generation of turbulent flow can be suppressed by reducing the change in the flow velocity of the air flowing along the inner edge surrounding the intake air, thereby reducing the intake noise.

  According to the first aspect of the present invention, there is provided a blower fan device comprising: a blower fan having a plurality of blade portions; and a fan casing that rotatably houses the blower fan and has at least one air inlet. Since the buffer member is disposed on the outer surface of the fan casing so as to surround the air inlet of the fan casing, the outer surface of the casing having the air inlet and the casing wall and circuit of the electronic device arranged to face the outer surface If the gap between the board and the surrounding mounting member is about several millimeters or less, the flow passage cross-sectional area of the air flowing toward the intake port along the outer surface of the fan casing in that gap (perpendicular to the ventilation direction) Turbulence is generated by reducing the flow velocity change of the air flowing along the inner edge surrounding the intake port. By suppressing, it can reduce intake noise.

  According to the second aspect of the present invention, since the inner surface side edge portion surrounding the air intake port is flattened on the inner surface of the fan casing, the air drawn from the air intake port of the fan casing surrounds the air intake port side. Even at the edge, turbulence is less likely to occur, and intake noise can be further reduced.

  In particular, in the centrifugal blower fan device, air is once sucked in the direction of the rotational axis of the blower fan, but immediately after that, the blower direction is changed to the centrifugal direction by the rotational movement of the blower fan. By flattening the inner side edge that surrounds the air inlet, the air smoothly flows in the centrifugal direction along the flat inner side edge even if the blade part and the fan casing are closer to each other. There is an effect of reducing the occurrence of turbulent flow at the side edge, and intake noise can be reduced.

  According to the third aspect of the present invention, since the buffer member is disposed along the inner edge surrounding the intake port, the air flow rate change can be alleviated uniformly over the entire outer peripheral area of the intake port. As a result, the effect of suppressing the occurrence of turbulent flow increases, and the effect of reducing intake noise improves.

  According to the invention described in claim 4, since the buffer member has an annular shape along the inner edge surrounding the intake port, it has the same shape as the intake port of the blower fan device, and the entire outer peripheral area of the intake port. The action of uniformly mitigating the change in the flow velocity of the air works, the action of suppressing the generation of turbulence is increased, and the effect of reducing the intake noise is improved.

  According to the fifth aspect of the present invention, since the radial cross section of the buffer member is rectangular, the buffer member and the housing wall, circuit board, or peripheral mounting of the electronic device arranged to face the buffer member Since the narrow gap with the member becomes uniformly long along the flow path direction, the pressure loss (ventilation resistance) of the buffer member against the air flowing toward the intake port along the outer surface of the fan casing increases, and it is more effective In addition, the generation of turbulent flow can be suppressed by reducing the change in the flow velocity of the air flowing along the inner edge that surrounds the intake port, and intake noise can be reduced.

  According to the sixth aspect of the present invention, since the shock absorbing member is made of a porous material having sound absorbing properties, the action of relaxing the flow velocity change of the air flowing along the inner edge surrounding the air inlet and the sound absorbing property of the shock absorbing member Due to the synergistic effect, intake noise can be further reduced.

  That is, when an intake noise is applied to a porous material such as flexible urethane foam, rubber sponge, or glass wool, the air vibration is directly transmitted to the air in the bubble portion inside the material. And the viscous friction of the air in the surface of a bubble is produced, and a part of sound energy is converted into a thermal energy, and a sound absorption effect is produced.

  Due to the resistance to the air movement, that is, the sound absorption effect that attenuates the air vibration, a slight gap from the air inlet of the blower fan device to the housing wall of the electronic device, the circuit board, or the surrounding mounting member Since the cushioning member made of this porous material is interposed in the transmission path of the intake noise that is transmitted and released to the outside, it acts to alleviate the change in the flow velocity of the air flowing along the inner edge surrounding the intake port described above In addition, the sound absorbing effect of the buffer member works effectively.

  According to the seventh aspect of the invention, since the buffer member and the fan casing are fixed by adhesion, not only the operation of arranging the buffer member on the outer surface of the fan casing is facilitated, but also the buffer member and the fan casing The sound absorbing effect of the buffer member works effectively together with the action of relaxing the flow velocity change of the air flowing along the inner edge surrounding the intake port.

  According to the invention described in claim 8, since the buffer member is constituted by connecting a plurality of buffer members, the cut shape of each unit buffer member constituting the buffer member is a simple linear or arc shape. The number of discarded materials during cutting such as punching from a roll-shaped base material is reduced, and the effective number per base volume of the base material is increased, thereby reducing the cost.

  According to invention of Claim 9, since the ventilation fan apparatus of any one of Claims 1-8 was provided, the space of the height direction in an electronic device is narrow by noise reduction of a ventilation fan apparatus. The fan casing of the blower fan device and the gap between the outer surface of the fan casing and the housing wall, circuit board, or peripheral mounting member of the electronic device disposed so as to face it are less than a few millimeters and sufficient ventilation Even when the road cannot be secured, sufficient quietness can be achieved, and not only the layout design within the housing of the electronic device can be facilitated, but also the electronic device on which the blower fan device is mounted can be made thinner and lighter. It becomes easy.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings, with the fan frame side as the lower side and the fan cover side as the upper side.

(Embodiment 1)
FIG. 1A is a perspective view of the blower fan device according to Embodiment 1 of the present invention, FIG. 1B is a cross-sectional view taken along the line AA of the blower fan device shown in FIG. 1 (b) is an enlarged partial cross-sectional view on the exhaust port side, FIG. 3 is an exploded perspective view of the blower fan device in Embodiment 1 of the present invention, and FIG. 4 (a) is Embodiment 1 of the present invention. FIG. 6 is a plan view of the blower fan device in FIG. 5, and (b) to (d) are plan views of modifications of FIG.

  First, as shown in FIGS. 1A and 1B, the fan casing 2 constituting the outer portion of the blower fan device 1 is composed of a fan frame 21 positioned at the lower portion and a fan cover 22 positioned at the upper portion. It is configured.

  Here, the bottom surface and the side surface of the fan frame 21 are integrated by resin molding using a resin material such as PPS, PBT, or PET, or die casting molding using a metal material having good moldability such as an aluminum alloy or zinc alloy. An air inlet 21a having a substantially circular shape is disposed at the center of the bottom surface, and an air outlet 3 for exhausting the intake air is disposed on one side surface. The fan cover 22 is also formed into a plate shape by resin molding or punching of a metal material such as an aluminum alloy or stainless steel, and an air inlet 22a opened in a substantially circular shape for sucking air is also formed in the center thereof. It is arranged.

  Further, the blower fan 4 is rotatably accommodated between the fan frame 21 and the fan cover 22, and the blower fan 4 has a hub portion 4a having a cylindrical outer peripheral surface and a substantially radial shape from the outer peripheral surface in a centrifugal direction. And a plurality of blade portions 4b extending continuously.

  Here, when the blower fan 4 rotates at a high speed in the direction indicated by the arrow, the air around the blower fan device 1 is arranged on the air inlet 22 a disposed in the center of the fan cover 22 and the bottom surface of the fan frame 21. The air is sucked in along the direction of the rotation axis 5 from both the intake port 21a provided, and the sucked air is further rotated in the fan casing 2 in the centrifugal direction of the plurality of blade portions 4b by the rotational movement of the blower fan 4. Since the wind direction can be changed, most of the air hits the inner walls of the fan frame 21 and the fan cover 22, and the air is sent along the inner walls in the same direction as the rotation direction of the blower fan 4. Exhaust from the exhaust port 3.

  Here, since the fan casing 2 covers the outer peripheral portion of the blade portion 4b of the blower fan 4, the air is collected at the outer peripheral portion by the rotation of the blower fan 4, and the amount of air necessary for blowing and static air are reduced. Pressure is generated.

  Further, the motor drive unit 6 is configured by a drive circuit board in which an electronic circuit for rotationally driving the rotary shaft 5 is incorporated, and the motor drive unit 6 is disposed on the bottom surface of the fan frame 21 and has an intake port. It is held via a motor holding part 7 extending from the fan frame 21 so as to cross 21a in a direction perpendicular to the intake direction.

  Further, as will be described in detail later, the fan cover 22 is located on the outer peripheral side from the tip of the blade portion 4b of the blower fan 4, and continues to be L-shaped from the exhaust port 3 toward the upstream side of the air. A wind tunnel portion 8 for preventing backflow is provided, and the inner height width of the wind tunnel portion 8 is set larger than the inner height width of the fan chamber located on the inner peripheral side from the tip of the blade 4b. The air flow path in the outer peripheral part of the blower fan 4 is secured by the wind tunnel part 8 for backflow prevention, and the air sent from the blower fan 4 in the centrifugal direction is a wind tunnel part for backflow prevention having a rapidly expanded space. The blowout is subsidized at 8, and the backflow of air from the exhaust port 3 to the blower fan 4 is prevented, and the air volume and static pressure characteristics are effectively secured.

  On the other hand, on the outer surface of the portion of the fan cover 22 where the wind tunnel 8 is not formed, the thickness is 0.5 to 0.5 along the inner edge 22b surrounding the air inlet 22a so as to surround the air inlet 22a. An annular buffer member 9 of about 1.5 mm is arranged.

  Here, the inner edge portion 22b is an edge portion of the fan cover 22 surrounding the substantially circular intake port 22a, and the air sucked into the blower fan device 1 along the inner edge portion 22b. Has been found to affect intake noise.

  Therefore, when the buffer member 9 is arranged so as to surround the air inlet 22a, the blower fan device 1 is mounted on an electronic device having a narrow space in the height direction, such as a notebook PC. When the clearance between the outer surface of the fan cover 22 having the air inlet 21a and the housing wall, circuit board, or peripheral mounting member of the electronic device disposed so as to face the fan cover 22 is about several millimeters or less. In the gap, the cross-sectional area (area in the direction orthogonal to the ventilation direction) of the air flowing toward the intake port 21a along the outer surface of the fan cover 22 is reduced, and the pressure loss (ventilation resistance) is increased. The generation of turbulent flow is suppressed by reducing the change in the flow velocity of the air flowing along the inner edge portion 22b surrounding the intake port 21a, and intake noise can be reduced.

  Further, the buffer member 9 is made of a porous material having a sound absorbing property that is separate from the fan casing 2, such as soft urethane foam, rubber sponge, glass wool, and the like. And the air vibration is directly transmitted to the air in the bubble inside the material.

  And the viscous friction of the air in the surface of a bubble is produced, and a part of sound energy is converted into a thermal energy, and a sound absorption effect is produced.

  Due to such a resistance to air movement, that is, a sound absorption effect that attenuates air vibrations, the air intake 22a of the blower fan device 1 is slightly connected to the housing wall, circuit board, or peripheral mounting member in the electronic device. Since the shock absorbing member 9 formed of this porous material is interposed in the transmission path of the intake noise that is released to the outside through the gap, the flow velocity of the air flowing along the inner edge 22b surrounding the intake port 22a described above The sound absorbing effect of the buffer member 9 works effectively together with the action of relaxing the change.

  Further, since the buffer member 9 has an annular shape along the inner edge 22b surrounding the intake port 22a, the buffer member 9 has the same shape as the intake port 22a of the blower fan device 1, and is formed in the entire outer peripheral area of the intake port 22a. The effect of suppressing the occurrence of turbulent flow is increased by relaxing the flow velocity change of the air flowing along the inner edge portion 22b that uniformly surrounds the air inlet 22a, and the effect of reducing the intake noise is improved.

  Further, as shown in FIG. 1B, since the radial cross section of the buffer member 9 is rectangular, the ventilation of the buffer member 9 with respect to the air flowing toward the intake port 22a along the outer surface of the fan cover 22 The resistance increases, and the generation of turbulence can be suppressed by reducing the change in the flow velocity of the air flowing along the inner edge 22b that surrounds the intake port 22a more effectively, thereby reducing intake noise.

  Further, since the inner surface side edge portion 22c (shown in FIG. 2) surrounding the air intake port 22a is flat, the air sucked from the air intake port 22a of the fan cover 22 is also turbulent on the inner surface side edge portion 22c side. Inhalation noise can be further reduced.

  In particular, in the centrifugal blower fan device 1, air is once sucked along the direction of the rotation axis of the blower fan 4, but immediately after that, the blowing direction in the centrifugal direction is changed by the rotational movement of the blower fan 4. Therefore, by flattening the inner surface side edge portion 22c of the fan cover 22, the air smoothly flows in the centrifugal direction along the flat inner surface side edge portion 22c even if the blade portion 4b and the fan cover 22 are brought closer to each other. Since it flows, the inner surface side edge portion 22c surrounding the intake port 22a has an action of suppressing the generation of turbulent flow, and intake noise can be reduced.

  Next, FIG. 2 partially overlaps using the enlarged partial cross-sectional view on the exhaust port 3 side of FIG. 1B. More specifically, the fan cover 22 has an outer peripheral side than the tip of the blade portion 4b. The inner height width 8h of the backflow prevention wind tunnel portion 8 located from the exhaust port 3 toward the upstream side of the air is equal to the inner height width 22h of the fan chamber located on the inner peripheral side from the tip of the blade 4b. Since it is set larger, the air channel in the outer peripheral part of the blade part 4b is secured by the wind tunnel part 8 for preventing the backflow, and the air sent out in the centrifugal direction from the blower fan 4 is a space that spreads rapidly. The air flow is supported by the wind tunnel portion 8 for preventing the backflow, and the backflow of the air from the exhaust port 3 to the blower fan 4 is prevented, and the air volume / static pressure characteristics can be effectively secured.

  On the other hand, on the outer surface of the portion of the fan cover 22 where the wind tunnel 8 is not formed, the thickness is 0.5 to 0.5 along the inner edge 22b surrounding the air inlet 22a so as to surround the air inlet 22a. A buffer member 9 having a rectangular cross section of about 1.5 mm in the radial direction is arranged.

  Since the inner surface side edge portion 22c surrounding the air intake port 22a is flat, the air sucked from the air intake port 22a of the fan cover 22 is less likely to be turbulent at the inner surface side edge portion 22c, thereby further reducing the intake noise. Can be reduced.

  In addition, since the cross section in the radial direction of the buffer member 9 is rectangular, the ventilation resistance of the buffer member 9 against the air flowing toward the intake port 22a along the outer surface of the fan cover 22 becomes larger, and the intake port 22a. The generation of turbulent flow can be suppressed by more effectively mitigating the change in the flow velocity of the air flowing along the inner edge portion 22b surrounding the inner edge 22b, and intake noise can be reduced.

  Next, as shown in FIG. 3, the fan frame 21 has a bottom wall 21b and a side wall 21c. The side wall 21c is formed in a substantially circular shape except for the side constituting the exhaust port 3 described above. The blower fan 4 that has a peripheral surface, is formed in a flat box shape as a whole, and that includes the hub portion 4a and the blade portion 4b via the motor holding portion 7 described above is rotatable. Is retained.

  After the fan frame 21 is placed on the fan cover 22 while the cylindrical rivets 21d formed at the four corners of the fan frame 21 are fitted into the rivet holes 22d at the four corners of the fan cover 22, The rivet 21d is crimped and fixed.

  Further, an annular cushioning member 9 is disposed on the outer surface of the portion of the fan cover 22 where the wind tunnel portion 8 is not formed, along the inner edge portion 22b surrounding the intake port 22a so as to surround the intake port 22a. The adhesive member 9 and the fan cover 22 are bonded to each other by a method suitable for attaching the buffer member having a rough surface, for example, an acrylic pressure-sensitive adhesive is applied to both sides of the non-woven cloth base material and the total thickness is increased. By fixing the double-sided tape 9a of about 0.1 to 0.2 mm to the lower surface of the buffer member 9 in advance and then attaching the buffer member 9 to the outer surface of the fan cover 22, the fixing operation is easy. In addition to this, the adhesion between the buffer member 9 and the fan cover 22 is improved, and the looseness is combined with the action of relaxing the flow velocity change of the air flowing along the inner edge 22b surrounding the air inlet 22a. Sound absorption effect of the member 9 is working effectively.

  In addition to the method using the double-sided tape 9a, an adhesive such as an epoxy adhesive or a silicon adhesive may be used.

  As shown in FIG. 4A, the annular buffer member 9 is arranged along the inner edge 22b surrounding the intake port 22a so as to surround the circular intake port 22a. However, it is separated from the inner edge 22b by substantially the same distance over the entire outer peripheral region, and has the same shape as the intake port 22a. The intake port 22a is uniformly distributed over the entire outer peripheral region of the intake port 22a. The action of suppressing the generation of turbulence is increased by relaxing the change in the flow velocity of the air flowing along the surrounding inner edge 22b, and the effect of reducing the intake noise is improved.

  In FIG. 4B, the annular buffer member 10 is disposed along the inner edge 22b surrounding the intake port 22a so as to surround the circular intake port 22a. The edge 22b and the inner peripheral side of the buffer member 10 are arranged so as to substantially coincide with each other, and have the same effect.

  Further, in FIG. 4C, a square-shaped buffer member 11 with a corner portion having an R is disposed so as to surround the circular intake port 22a, and the buffer member 11 has four units. Since the buffer member is configured to be connected by the four connecting portions 11a, the cutting shape of each unit buffer member constituting the buffer member 11 becomes a simple linear shape, and is punched from a roll-shaped base material. The material discarded at the time of cutting, etc. is reduced, the effective number of base materials per unit volume is increased, and the cost can be reduced.

  Similarly, in FIG. 4D, the elliptical buffer member 12 is arranged so as to surround the circular intake port 22a, and this buffer member 12 has two unit buffer members connected in two places. Since it is configured to be connected by the portion 12a, the cutting shape of each unit buffer member constituting the buffer member 12 becomes a simple arc shape, and is discarded at the time of cutting processing such as punching from a roll base material. The material is reduced, the effective number of base materials per unit volume is increased, and the cost can be reduced.

(Embodiment 2)
FIG. 5A is a diagram showing the inside of the casing of the electronic device according to the second embodiment of the present invention, and FIG. 5B is a cross-sectional view showing the main part of FIG. The electronic device 50 is a notebook PC having a configuration in which an openable liquid crystal display device 51 is rotatably supported by a hinge mechanism 53 at an end of a main body device 52 having an operation unit.

  In this figure, a heat generating electronic component (not shown) to be cooled is mounted on the lower surface of the circuit board 54 disposed inside the housing of the main device 52 of the electronic device 50. 2 shows a state in which a heat sink 55 having a plurality of heat radiation fins that are thermally connected to each other is installed on the housing side surface 52a side of the main body device 52.

  The blower fan device 56 is substantially the same as the configuration described in the first embodiment, and is mounted below the circuit board 54 so as to be adjacent to the heat sink 55 described above, and the fan cover 57 is on the lower side. The fan frame 58 is oriented upward.

  The air on the lower side of the main body device 52 passes through the plurality of vent holes 59 provided on the housing bottom surface 52b side of the main body device 52 and is sucked from the air inlet 57a of the fan cover 57, and at the same time. The air inside the fan 52 is sucked from the air inlet 58a of the fan frame 58, and in the centrifugal direction of the blower fan 60 inside the fan casing constituted by the fan cover 57 and the fan frame 58 by the rotational movement of the blower fan 60. The air direction is changed so that most of the air hits the inner wall of the fan frame 58 and the fan cover 57, and the air is sent along the inner wall in the same direction as the rotation direction of the blower fan 60. 61 is exhausted and passes through the gaps between the heat radiation fins of the heat sink 55 while exchanging heat. Through the vent 62 provided in it is discharged to the outside.

  Here, since the gap sandwiched between the housing bottom surface 52b of the main unit 52 and the fan cover 57 is about 1 to 2 mm or less, the flow velocity of the air flowing through the gap is increased and sucked into the intake port 57a. Most of the air flows along the vicinity of the inner edge 57b, and the flow direction greatly changes in the direction perpendicular to the direction of the rotation axis of the blower fan 60 from the direction along the outer surface of the fan cover 57. However, in order to surround the air inlet 57a of the fan cover 57, an annular buffer having a thickness of about 0.5 to 1.5 mm along the inner edge 57b surrounding the air inlet 57a. Since the member 63 is arranged, the cross-sectional area of the flow path of air flowing along the outer surface of the fan cover 57 toward the intake port 57a (area in the direction orthogonal to the ventilation direction) is reduced, and pressure loss (ventilation) is reduced. Anti) by suppressing the generation of turbulence in relieving the changes in flow velocity of the air flowing along the inner edge 57b surrounding the at increased inlet 57a, thereby reducing the intake noise.

  The buffer member 63 is made of a porous material having a sound absorbing property separate from the fan cover 57, for example, soft urethane foam, rubber sponge, glass wool, and the like. And the air vibration is directly transmitted to the air in the bubble inside the material.

  And the viscous friction of the air in the surface of a bubble is produced, and a part of sound energy is converted into a thermal energy, and a sound absorption effect is produced.

  Due to the resistance to the air movement, that is, the sound absorption effect that attenuates the air vibration, a slight gap between the housing bottom surface 52b and the circuit board 54 in the electronic device 50 from the air inlet 58a of the blower fan device 56 is formed. Since the buffer member 63 formed of this porous material is interposed in the transmission path of the intake noise that is transmitted and released to the outside, the flow velocity change of the air flowing along the inner edge 57b surrounding the intake port 57a described above is changed. In addition to the mitigating action, the sound absorbing effect of the buffer member 63 works effectively.

  Incidentally, the blower fan 56 having the configuration described in the first embodiment, the blower fan 60 having the maximum outer diameter of 46 mm and the inlets 57a and 58a of 28 mm in diameter is mounted on the electronic device 50, and the blower fan. When the device 56 is driven at a rotational speed of 2900 rpm, noise measured outside the electronic device by arranging a width buffer member 63 having a radial cross-sectional shape of 1.0 mm (thickness) × 2.5 mm (width) It was confirmed that the value was improved by about 0.5 dBA.

  In the above description of the embodiments, the dimensions, quantities, materials, shapes, relative arrangements, and the like of the constituent elements are within the scope of the present invention unless otherwise specified. The present invention is not intended to be limited to this, but is merely a description of one embodiment, and various modifications are possible.

  For example, in both of the first embodiment and the second embodiment, the buffer member is disposed so as to surround only the air intake of the fan cover, but not only the fan cover but also the air intake of the fan frame, You may arrange | position a buffer member by the same structure.

  In the electronic device 50 according to the second embodiment, the gap between the housing bottom surface 52b of the main body device 52 and the fan cover 57 is about 1 to 2 mm or less, and the inner edge 57b surrounding the air inlet 57a is formed. Since the annular buffer member 63 having a thickness of about 0.5 to 1.5 mm is disposed along the air flow path, a slight gap of about 0.5 to 1.5 mm is formed in the air flow path therebetween. However, if there is a sufficient air flow path that can be supplied to the intake port 57a or the intake port 58a in addition to the air flow channel that can pass through the gap, the buffer member 63 is brought into contact with the housing bottom surface 52b. The flow path in the gap may be closed, and the upper side of the buffer member 63 may be bonded to the housing bottom surface 52b.

  However, in this case, since the buffer member 63 and the housing wall, circuit board, or peripheral mounting member of the electronic device 50 disposed so as to face the buffer member 63 cannot be avoided, the soft cushion It is preferable to use a material having a property as the buffer member 63.

  The blower fan has also been described in the case of using a centrifugal blower fan. Instead, an axial blower fan is used to suck air from only one side surface of the fan casing, A buffer member may be disposed on the outer surface of the fan casing so as to surround it.

  Further, the configuration of the fan casing is not simply composed of a fan cover and a fan frame. For example, a heat receiving part that makes thermal connection with a heat generating electronic component is provided in a part of the fan frame, or heat dissipation. A heat sink having heat conductivity may be integrally provided by die casting or press molding, and further equipped with a heat transport member such as a heat pipe or a heat conductive sheet for efficiently performing heat transport therebetween. It may be.

  The cooling device of the present invention can be applied to a cooling device for heat-generating electronic components such as an MPU mounted on a thin and light mobile electronic device such as a notebook PC, a mobile phone, and a PDA.

(A) The perspective view of the ventilation fan apparatus in Embodiment 1 of this invention, (A) AA arrow sectional drawing of the ventilation fan apparatus shown to (a) Partial cross-sectional enlarged view of the exhaust port side in FIG. The disassembled perspective view of the ventilation fan apparatus in Embodiment 1 of this invention (A) The top view of the ventilation fan apparatus in Embodiment 1 of this invention, The top view of the modification of (b)-(d) (a). (A) The figure which showed the inside of the housing | casing of the electronic device in Embodiment 2 of this invention, (b) Sectional drawing which showed the principal part of (a) A perspective view of a heat sink-integrated blower fan device described in Patent Document 1 which is a conventional technique Partial sectional view in the axial direction of a centrifugal blower fan device described in Patent Document 2 which is a conventional technique

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Blower fan device 2 Fan casing 3 Exhaust port 4 Blower fan 4a Hub part 4b Blade part 5 Rotating shaft 6 Motor drive part 7 Motor holding part 8 Wind tunnel part 8h Inner height width of a wind tunnel part 9 Buffer member 9a Double-sided tape 10 Buffer member DESCRIPTION OF SYMBOLS 11 Buffer member 12 Buffer member 21 Fan frame 21a Air inlet 21b Bottom wall 21c Side wall 21d Rivet 22 Fan cover 22a Air inlet 22b Inner edge 22c Inner surface side edge 22d Rivet hole 22h Inner height width of fan chamber 50 Electronic device 51 Liquid crystal Display device 52 Main body device 52a Housing side surface 52b Housing bottom surface 53 Hinge mechanism 54 Circuit board 55 Heat sink 56 Blower fan device 57 Fan cover 57a Intake port 57b Inner edge portion 58 Fan frame 58a Inlet port 59 Ventilation port 60 Blower fan 61 Exhaust port 62 Ventilation 63 cushioning member

Claims (9)

A blower fan device comprising: a blower fan having a plurality of blade parts; and a fan casing that rotatably accommodates the blower fan and has at least one air inlet, so as to surround the air inlet. A blower fan device comprising a buffer member disposed on an outer surface of the fan casing. The blower fan device according to claim 1, wherein an inner surface side edge portion of the fan casing surrounding the intake port is flattened. The blower fan device according to claim 1, wherein the buffer member is disposed along an inner edge surrounding the intake port. The blower fan device according to claim 1, wherein the buffer member is formed in an annular shape along an inner edge portion surrounding the intake port. The blower fan device according to claim 4, wherein a radial cross section of the cushioning member is rectangular. The blower fan device according to claim 1, wherein the buffer member is made of a porous material having a sound absorbing property. The blower fan device according to claim 6, wherein the buffer member and the fan casing are fixed by adhesion. The blower fan device according to claim 1, wherein the buffer member is configured by connecting a plurality of buffer members. An electronic apparatus comprising the blower fan device according to claim 1.

Images