JP2009156187A - Electronic apparatus provided with centrifugal fan device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic apparatus provided with a centrifugal fan device capable of improving an air flow and static pressure by increasing a flow rate to a centrifugal direction when the centrifugal fan device is disposed in a narrow space, intervals with members disposed oppositely to each intake port are different, and the balance of the air duct resistance of a space between the oppositely disposed members. <P>SOLUTION: A cylindrical section upper side pressure surface tip Ea of a blade 19a facing an intake port having a narrower interval with the oppositely disposed member is positioned at a fan rotation direction indicated by an allow R of a lower pressure surface tip Eb of the blade 19a facing an intake port having a wider interval with the oppositely disposed member. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electronic device in which a centrifugal fan device used for cooling a heating element such as an ultra-compact processing unit (hereinafter referred to as MPU) or circulating an air is mounted inside a casing. A centrifugal fan device that forcibly blows and cools the radiator and forcibly circulates the air inside the housing The present invention relates to an electronic device provided.

  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 heat generation amount of the MPU increases, and not only the conventional method of dissipating heat by contacting a heat sink having a heat radiation fin with the heat generating body, but also the method of cooling the heat sink directly by the blow of a fan, or the heat receiving body and heat dissipation A heat sink module that is thermally connected to the body using a heat pipe is configured to forcibly cool the heat radiating body by blowing air from a fan, and a liquid refrigerant having high thermal conductivity is forcibly circulated by a pump and For example, it is indispensable to forcibly blow and dissipate heat from a radiator that has been transported to and from the heat radiating unit using a centrifugal fan device. In the future, it will be necessary to further improve its cooling performance and make it smaller and thinner. It is said that.

  On the other hand, the improvement of the cooling performance by the centrifugal fan device described above largely depends on the improvement of the air blowing performance such as high air volume and high static pressure. Generally, the air blowing performance of the centrifugal fan device depends on the rotational speed of the centrifugal fan. Although it is possible to improve the noise by raising it, since the wind noise (hereinafter referred to as fan noise) of the centrifugal fan blade portion of the centrifugal fan device also tends to increase, the fan noise is increased. The air flow in the centrifugal direction is suppressed by suppressing the air flow that is once taken into the pressure surface side of the blade part from the intake port and goes to the suction surface side beyond the upper and lower ends extending in the radial direction of the blade part. The shape of the blade part that can increase the above has been proposed (see, for example, Patent Document 1 and Non-Patent Document 1).

  FIG. 12 is a perspective view of a centrifugal fan described in (Patent Document 1). The pressure surface shape of a cylindrical section of a blade section cut along a cylinder having a predetermined radius coaxial with the rotation axis is such that both end portions are It has a concave shape that is positioned on the rotational direction side of the central portion.

  More specifically, in the blade portion 107 located in the projection area region of the intake port (not shown), the shape on the pressure surface 113 side of the cylindrical cross section of the blade portion 107 cut along a cylinder having a predetermined radius coaxial with the rotation shaft 108 is Both end portions are concave shapes located on the rotation direction side indicated by the arrow R from the center portion.

  FIG. 13A is a cross-sectional view taken along the line DD of the blade portion 107 of FIG. 12, and shows an arc DD that is a cylindrical cross section cut along a virtual cylinder having a predetermined diameter coaxial with the rotation shaft 108. The shape of the cut surface along is shown.

  As shown in this figure, the shape of the blade section 107 on the pressure surface 113 side of the cylindrical cross section is such that the lower end Ea and the upper end Eb of the blade section 107 are more than the central section C of the blade section 107. In addition to the concave shape located on the traveling direction S side, the angle (elevation angle) θa of the lower end Ea and the upper end Eb of the blade portion 107 with respect to the traveling direction S viewed from the central portion C of the blade portion 107, It is preferable that each θb has a shape of 55 to 85 degrees.

  In this embodiment, the central portion C in the direction of the rotation axis 108 of the blade portion 107 has a substantially flat shape, and the lower end portion Ea and the upper end portion Eb are slightly inclined toward the traveling direction S side. However, the shape of the blade section 107 on the pressure surface 113 side of the cylindrical cross section is such that the angles (elevation angles) θa and θb between the lower end Ea and the upper end Eb are in the range of 55 to 85 degrees, respectively. Well, for example, as shown in FIG. 13B, which is a modified example of FIG. 13A, a curved shape in which the shape on the pressure surface 113 side of the cylindrical cross section is recessed in a curve, or another modification of FIG. As shown in FIG. 13C as an example, the shape on the pressure surface 113 side of the cylindrical cross section may be a triangular shape that is linearly depressed.

  In this way, by forming the respective angles (elevation angles) θa and θb of the lower end portion and the upper end portion to 55 to 85 degrees, the intake ports can be formed by the angles (elevation angles) θa and θb being too small. The air amount taken into the pressure surface 113 side of the blade portion 107 is insufficient, or conversely, the angles (elevation angles) θa and θb are too large, so that the blade portion 107 tries to go around to the negative pressure surface 114 side. Since the action of suppressing the air flow is rarely insufficient, and the flow rate in the centrifugal direction can be increased more effectively, it is easy to increase the air volume and increase the static pressure.

Although not shown, (Non-Patent Document 1) also proposes a shape of a blade portion of a centrifugal fan that can increase the air volume by suppressing the loss that the air sucked from the vertical direction cannot change direction and escapes downward. As in (Patent Document 1), the pressure surface shape of the cylindrical cross section of the blade portion cut along a cylinder having a predetermined radius coaxial with the rotation axis is such that both end portions are positioned on the rotational direction side of the central portion. It has a concave shape.
JP 2007-247495 A (page 13, FIGS. 6 to 7) Proceedings of the Heat Transfer Society of Japan (2006, Vol. 14, No. 1, page 15, Fig. 12 (a), (b))

  In general, the blowing performance of a fan device is indicated by the characteristic value of the air volume and static pressure, and the higher the respective values of the air volume and static pressure, the higher the blowing performance.

  In other words, if the air path resistance that hinders ventilation in the sealed air flow path, that is, the so-called pressure loss increases, the required air volume cannot be obtained as a result. A fan device having an air flow static pressure characteristic that exceeds the pressure loss in the road can obtain a desired air volume required for cooling a heating element such as an MPU. The air blowing performance is shown.

  On the other hand, when the shape of the pressure surface of the blade part is a simple linear shape or a gentle arcuate shape, it is easy to simply increase the length or width of the blade part to increase the surface area of the pressure surface of the blade part. Although the air volume and static pressure can be increased, the fan device as a whole is increased in size, and it is difficult to mount it on a small or thin electronic device with little free space inside the housing.

  In addition, the air volume and static pressure can be increased by increasing the rotational speed of the centrifugal fan, but as described above, due to a sudden change in air pressure at the tip of the blade part or the end in the rotation axis direction. The fan noise also increases, and it becomes difficult to mount it on information processing equipment, audio equipment, or video equipment that is particularly required to be quiet.

  For the above reasons, the air flow static pressure characteristics are improved without simply increasing the outer dimensions of the blade section and width, and without increasing the rotational speed of the centrifugal fan, improving the cooling performance and downsizing. However, the conventional centrifugal fan described above cannot achieve a sufficient effect.

  There is also a demand for downsizing or thinning of electronic devices in which the centrifugal fan device is mounted internally, such as mobile notebook computers and DVD players. In addition to the very small empty space, the airflow resistance (spacing) of the air sucked from the intake port provided in the vertical direction (longitudinal direction of the rotating shaft) of the fan casing of the mounted centrifugal fan device is mutually In that case, conventional centrifugal fan devices such as (Patent Document 1) and (Non-Patent Document 1) cannot inhale air in a well-balanced manner, and as a result, a sufficient air volume is obtained. There was a problem that it was difficult to ensure.

  In other words, even if the centrifugal fan device is arranged in a narrow space, the distance between the members opposed to the respective intake ports is substantially equal, and the balance of the air path resistance between the members arranged opposite to each other is ensured. In the case where the pressure surface shape of the blade portion is simply a vertically symmetrical concave shape, the air on the pressure surface of the blade portion is once swept away in the centrifugal direction by the centrifugal force of the rotating blade portion, A part of the air then flows from the upper and lower ends extending in the radial direction of the blade portion also in the direction of the rotation axis, and passes around the upper and lower ends extending in the radial direction and wraps around the suction surface of the blade portion. Since the intended air flow is suppressed, the corresponding air flows in the centrifugal direction, and the flow rate of the air substantially increases.

  However, the airflow resistance of the air that flows into the upper and lower air intakes from the vertical direction of the fan casing is limited to the members such as the keyboard, mounting circuit, and electronic device housing wall that are arranged to face the air intakes at a predetermined interval. In the case where the distance between the member arranged opposite to each intake port is greatly affected by the interval and the distance between the member arranged opposite to each intake port is different from each other, the magnitude of the air path resistance with the smaller interval between the member arranged opposite to the intake port is The distance between the opposed member and the intake port is relatively larger than the magnitude of the air path resistance.

  As a result, the concave shape on the pressure surface side at the end of the blade portion facing the air intake increases the air volume for the air drawn from the air intake on the side where the air path resistance is large (side where the interval is narrow). Although it works effectively, the air sucked from the intake port on the side where the air path resistance is small (the side where the interval is wide) is in spite of the state that it can carry (supply) a sufficient amount of air. On the other hand, the concave shape on the pressure surface side of the end of the blade facing the intake port acts in the direction that reduces the volume that carries air in the centrifugal direction, and as a whole, air is efficiently sent out in the centrifugal direction. There was a problem that the air volume could not be increased.

  In order to solve the above-described problems, an electronic device according to the present invention includes a centrifugal fan device having a plurality of blade portions radially about a rotation axis and two predetermined upper and lower intake ports of a fan casing of the centrifugal fan device. An electronic device comprising a member arranged oppositely so as to be parallel to each other, wherein the interval between one intake port and the member arranged opposite to the intake port is the same as that of the other intake port The pressure surface shape of the cylindrical cross section of the blade section cut along a cylinder having a predetermined radius coaxial with the rotation axis is smaller than the distance between the oppositely arranged member and the member having the smaller distance from the oppositely arranged member. The tip of the pressure surface at the end of the blade portion facing the air intake port of the blade is positioned closer to the fan rotation direction than the front end of the pressure surface at the end of the blade portion facing the air intake port with the wider space between the oppositely arranged members When It has been a major feature of the Rukoto.

  In the electronic device according to the present invention, even when the centrifugal fan device is disposed in a narrow space and it is difficult to ensure the balance of the air path resistance by keeping the same distance from the members disposed facing the respective intake ports. The effect of suppressing the air flow around the suction surface side beyond the end portion extending in the radial direction of the blade portion with respect to the end portion of the blade portion facing the intake port having the narrower interval with the opposingly arranged member By being selectively obtained, as a whole, the sucked air can be efficiently sent in the centrifugal direction to increase the air volume.

  According to the first aspect of the present invention, the centrifugal fan device having a plurality of blade portions radially about the rotation axis and the two upper and lower intake ports of the fan casing of the centrifugal fan device are parallel to each other with a uniform predetermined interval. An electronic device including a member disposed so as to be opposed to each other, and an interval between one intake port and the member disposed opposite to the intake port is opposed to the other intake port and the intake port. The pressure surface shape of the cylindrical section of the blade section cut along a cylinder having a predetermined radius coaxial with the rotation axis is smaller than the distance between the adjacent members and faces the intake port with the smaller distance from the oppositely arranged members. By adopting a shape that is located on the fan rotation direction side of the pressure surface tip at the end of the blade portion facing the air inlet with the wider space between the tip of the pressure surface at the end of the blade portion and the oppositely disposed member, Centrifuge Even when it is difficult to secure the balance of the air path resistance by arranging the fan device in a narrow space and keeping the same distance from the members opposed to the respective intake ports, Since the effect of suppressing the air flow around the suction surface side beyond the end portion extending in the radial direction of the blade portion with respect to the end portion of the blade portion facing the narrower inlet is selectively obtained, the whole As a result, the sucked air can be sent out in the centrifugal direction to increase the air volume.

  In other words, for the air sucked from the intake port on the side where the interval is narrow (the side where the air path resistance is large), the tip of the pressure surface at the end of the blade part facing the intake port is located on the fan rotation direction side. It works effectively against the increase in air volume, and is able to carry (supply) a sufficient volume of air for the air drawn from the air inlet on the side with the larger interval (the side with the smaller airflow resistance) Therefore, the tip of the pressure surface at the end of the blade facing the air inlet acts in the direction of increasing the volume that carries the air in the centrifugal direction, and as a whole, the air is efficiently sent out in the centrifugal direction and the air volume is increased. Can do.

  In addition, since the air blowing efficiency is improved, it becomes easier to cope with the downsizing and thinning of the centrifugal fan device, and as a result, the electronic device mounted with the centrifugal fan device can be easily downsized and thinned.

  According to the second aspect of the present invention, the centrifugal fan device having a plurality of blade portions radially about the rotation axis and the two upper and lower intake ports of the fan casing of the centrifugal fan device are arranged to face each other at a predetermined interval. The air path resistance of the space sandwiched between one intake port and the member disposed opposite to the intake port is disposed opposite to the other intake port and the intake port. The pressure surface shape of the cylindrical section of the blade section cut along a cylinder having a predetermined radius coaxial with the rotation axis is smaller than the air path resistance of the space sandwiched between the members, and the space between the opposing members Positive air pressure at the end of the blade part facing the air inlet with the smaller air path resistance in the space between the end of the pressure surface at the end of the blade part facing the air inlet with the larger air path resistance Fan rotation than pressure side tip When the centrifugal fan device is placed in a narrow space and it is difficult to ensure the balance of the airflow resistance of the space between the members placed opposite to the respective air inlets by adopting the shape located on the opposite side Also, the end of the blade portion facing the intake port with the larger air path resistance in the space between the opposed members and the end portion extending in the radial direction of the blade portion is on the suction surface side. Since the effect of suppressing the flowing air is selectively obtained, as a whole, the sucked air can be efficiently sent out in the centrifugal direction to increase the air volume.

  In other words, for the air sucked from the intake port on the side where the air path resistance of the space between the opposed members is large, the tip of the pressure surface at the end of the blade portion facing the intake port is the fan rotation direction Because it is located on the side, it effectively works against the increase in the air volume, and it has a sufficient volume for air sucked from the air inlet on the side where the air path resistance of the space between the opposed members is small. Since the air volume can be carried (supplied), the tip of the pressure surface at the end of the blade facing the air inlet acts in the direction of increasing the volume that carries the air in the centrifugal direction. The amount of air can be increased by feeding in the centrifugal direction.

  In addition, since the air blowing efficiency is improved, it is easy to cope with the downsizing and thinning of the centrifugal fan device, and as a result, the electronic device mounted with the centrifugal fan device can be easily downsized and thinned.

  According to the third aspect of the present invention, the distance between the air inlet having the larger distance from the oppositely arranged member and the member is Sb, and the air inlet having the smaller distance from the oppositely arranged member and the air inlet When the interval between the members is Sa, by satisfying the relations of 1.5 mm <Sb <3.5 mm and 0 <Sa <0.5 Sb, the centrifugal fan device is arranged oppositely even in a narrower space. 50% of the larger distance between the inlet and the narrower air inlet, which is selected in the range of 1.5mm to 3.5mm, with the wider distance between the members and the oppositely disposed member. Therefore, it is more negative than the end portion of the blade portion facing the intake port with the smaller distance from the oppositely arranged member beyond the end portion extending in the radial direction of the blade portion. The effect of suppressing the air flow around the pressure side is selectively obtained. By being, can be increased as a whole, the airflow sent out efficiently sucked air in the centrifugal direction.

  In other words, if the distance between the oppositely arranged members is wider and is selected in the range of 1.5 mm to 3.5 mm, the narrower distance between the oppositely arranged members is 50% or less of the wider distance. If it exists, the effect | action of this invention is fully acquired.

  According to the fourth aspect of the present invention, the intake port with the larger interval between the tip of the pressure surface at the end of the blade portion facing the intake port with the smaller interval between the members arranged opposite to the member arranged opposite to the intake port. By setting the length of the arc on the same plane between the end of the blade portion facing the pressure surface and the tip of the pressure surface in the range of 10% to 40% of the width in the rotation axis direction of the blade portion, the centrifugal fan device Even if the width of the blade portion in the rotational axis direction changes, the end portion extending in the radial direction of the blade portion with respect to the end portion of the blade portion facing the intake port having the narrower distance from the oppositely arranged member Since the effect of suppressing the air flow that circulates to the negative pressure surface side can be selectively and appropriately obtained, the sucked air can be efficiently sent out in the centrifugal direction as a whole, and the air volume can be increased.

  According to the fifth aspect of the present invention, in the blade portion located in the projected area region of the air inlet, the pressure surface shape of the cylindrical section of the blade portion cut along the cylinder having a predetermined radius coaxial with the rotation axis is formed on both sides. Compared with the outer peripheral portion of the blade portion of the centrifugal fan accommodated in the fan casing, the tip of the positive pressure surface has a concave shape that is located on the fan rotation direction side of the center portion. The projected area of the shape of the intake port is negative from the pressure surface of the blade part located in that region because the air flow once taken into the pressure surface side of the blade part from the intake port does not act as rectification by the fan casing. Since the air flow which tries to go around to the pressure side is suppressed, the air flows in the centrifugal direction, and the flow rate of the air substantially increases.

  On the other hand, the area of the peripheral part of the blade part of the centrifugal fan is surrounded by the fan casing, and the rectifying action that allows air to flow only in one direction in the centrifugal direction works effectively. The shape can be set to a desired shape.

  According to the sixth aspect of the present invention, at the outer peripheral portion of the blade portion, at least one end portion located at both end portions in the rotation axis direction is notched, and the edge portion surrounding the air inlet of the fan casing is cut. By arranging so as to enter the lacked part, the width of the blade portion located in the projected area area of the inlet can be increased without increasing the height of the outer shape of the centrifugal fan device, The air volume increases.

  For example, at least one end located at both ends in the rotation axis direction of the outer peripheral portion of the blade portion is cut out in an L shape so that the edge surrounding the air inlet of the fan casing enters the cut out portion. If arranged, the height of the outer shape of the centrifugal fan device can be reduced and the thickness can be further reduced, and as a result, the electronic device mounted with the centrifugal fan device can be easily reduced in size and thickness.

  Moreover, if the clearance between the upper and lower ends of the outer peripheral portion of the blade portion of the centrifugal fan device and the case wall having the air inlet of the fan casing is made smaller, rectification that allows air to flow only in one direction of the centrifugal direction. The action can be made to work more effectively.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each of the drawings, FIGS. 1A and 1B are described with the fan frame side as the upper side and the fan cover side as the lower side, and FIGS. 2 to 10 with the fan frame side as the lower side and the fan cover side as the upper side. To do.

(Embodiment 1)
1A is a view showing the inside of the casing of the electronic device according to Embodiment 1 of the present invention, and FIG. 1B is a cross-sectional view showing the main part of FIG. FIG. 3 is a perspective view from above of the centrifugal fan device in Embodiment 1 of the present invention, FIG. 3 is a perspective view from above of the centrifugal fan in Embodiment 1 of the present invention, and FIG. FIG. 4B is a plan view of the centrifugal fan device according to the first embodiment of the present invention, FIG. 4B is a cross-sectional view taken along the line AA in FIG. 4A, and FIG. 5 is the first embodiment according to the present invention. FIG. 6A is a cross-sectional view taken along the line B-B in FIG. 5, FIG. 6B is a cross-sectional view showing a modified example of FIG. FIG. 8A is a partially enlarged perspective view of the centrifugal fan according to the first embodiment of the present invention, FIG. 8A is a cross-sectional view taken along the line CC of FIG. 7, and FIG. a) FIG. 8C is a cross-sectional view showing a modified example of FIG. 8A, and FIG. 9 is a cross-sectional view of the inlet and the member having a narrower distance from the opposed member. FIG. 10 is a graph showing the relationship of the maximum air volume with respect to the distance Sa between the intake port and the air gap with respect to the distance Sb between the inlet having a larger distance between the opposed members and the member than in the conventional flat shape. It is a graph which shows the relationship of the space | interval Sa to start.

  First, FIG. 1A shows an electronic device 13 such as a notebook PC having a configuration in which an openable liquid crystal display device 10 is rotatably supported by a hinge mechanism 12 at an end of a main body device 11 having an operation unit. FIG. 1B shows a cross-sectional view showing the main part of FIG.

  In this figure, a heat generating electronic component (not shown) to be cooled is mounted on the lower surface of the circuit board 14 arranged inside the housing of the main body device 11 of the electronic device 13, and the heat generating electronic component A state in which a heat sink 15 including a plurality of heat radiation fins that are thermally connected to each other is installed on the housing side wall 11a side of the main body device 11 is shown.

  The centrifugal fan device 16 is mounted below the circuit board 14 so as to be adjacent to the heat sink 15 described above so that the fan cover 17 faces downward and the fan frame 18 faces upward. Has been placed.

  Then, the air on the lower side of the main body device 11 passes through the plurality of vents 11c provided on the housing bottom wall 11b side and enters the inside of the main body device 11. The air on the side of the main body device 11 is It passes through the vent 11e of the body side wall 11d and enters the inside of the main body device 11, flows through the upper and lower spaces of the circuit board 14, and flows in the direction of the centrifugal fan device 16 around the circuit board 14 and other internal members. The air is sucked into the centrifugal fan device 16 from the air inlet 17a of the fan cover 17 and the air inlet 18a of the fan frame 18.

  Then, the air sucked into the centrifugal fan device 16 is directed to the centrifugal direction of the blower fan 19 which is arranged so as to be accommodated in a fan casing composed of the fan cover 17 and the fan frame 18 and rotates. Therefore, most of them collide with the inner walls of the fan frame 18 and the fan cover 17, and the air is sent along the inner wall in the same direction as the rotation direction of the blower fan 19. 20 is exhausted.

  Further, the exhausted air passes through the gap between the heat sink fins of the heat sink 15 while exchanging heat (heat absorption) with the heat sink fins, and passes through the vent 11 f provided in the housing side wall 11 a of the main body device 12. Finally, the air is exhausted to the outside of the electrical device 13.

  That is, the electronic device 13 includes the centrifugal fan device 16 having a plurality of blade portions 19a (see FIG. 2) radially about the rotation shaft 21, and the exhaust port 20 thereof is disposed so as to face the heat sink 15. The centrifugal fan device 16 performs forced cooling of the heat-generating electronic components described above indirectly by blowing and cooling the heat sink 15.

  In addition, inside the electronic device 13, the housing bottom wall 11 b is disposed so as to be parallel to the air inlet 17 a of the fan cover 17 at a uniform predetermined interval, and is opposed to the air inlet 18 a of the fan frame 18. On the other hand, the circuit board 14 is disposed so as to be parallel to each other with a uniform predetermined interval.

  The gap between the fan cover 17 and the housing bottom wall 11b has a narrow air path resistance because the gap Sa is as narrow as about 1 mm to 2 mm, and is sandwiched between the fan frame 18 and the circuit board 14. As for the gap, the space Sb is about 2 mm to 4 mm, and a sufficient space for air blowing is secured and the air path resistance is small.

  In other words, the distance Sa between the air inlet 17a of the fan cover 17 and the housing bottom wall 11b disposed opposite to the air inlet 17a is equal to the circuit board 14 disposed opposite to the air inlet 18a of the fan frame 18 and the air inlet 18a. The pressure surface shape of the cylindrical cross section of the blade portion 19a cut along a cylinder having a predetermined radius coaxial with the rotation shaft 21 is smaller than the distance Sb between the suction port 17a and the inlet 17a having the narrower distance from the opposed member. The pressure surface tip Ea (see FIG. 3) at the end of the blade portion 19a facing the intake port 18a having the larger space between the pressure surface tip Eb (see FIG. 3) at the end of the blade portion 19a facing the member. The shape is located closer to the fan rotation direction than the reference).

  Next, as shown in FIG. 2, the thin box-shaped fan casing 22 indicated by the one-dot chain line of the centrifugal fan device 16 includes a fan frame 18 positioned below and a fan cover 17 positioned above the fan frame 18. Has been.

  Here, the fan frame 18 is integrally formed with a bottom wall and a side wall by resin molding, die casting of an aluminum alloy, or the like, and an exhaust port 20 for exhausting the intake air is disposed on one side wall thereof. An intake port 18a is disposed on the bottom wall.

  The fan cover 17 is formed into a plate shape by stamping or resin molding of a metal material such as aluminum or stainless steel, and a substantially circular intake port 17a for sucking air is disposed at the center thereof. Has been.

  A centrifugal fan 19 is disposed so as to be sandwiched and accommodated between the fan frame 18 and the fan cover 17, and the centrifugal fan 19 has a cylindrical outer peripheral surface and a hub portion 19 b having an outer peripheral surface in the centrifugal direction. A plurality of blade portions 19a extending substantially radially, and an annular ring continuously connected in the circumferential direction to an end portion located above the outer peripheral portion of the blade portion 19a in the direction of the rotation shaft 21 (see FIG. 3B). The plate 19c is integrally formed.

  Further, as described above, the distance Sa between the air inlet 17a of the fan cover 17 and the housing bottom wall 11b arranged to face the air inlet 17a is arranged to face the air inlet 18a of the fan frame 18 and the air inlet 18a. The pressure surface shape of the cylindrical section of the blade portion 19a cut along a cylinder having a predetermined radius coaxial with the rotating shaft 21 is smaller than the distance Sb between the circuit board 14 and the circuit board 14, and the distance between the oppositely arranged members is narrow. The pressure surface at the end of the blade portion 19a facing the air intake port 18a having a larger distance from the member on which the pressure surface tip Eb (see FIG. 3) at the end of the blade portion 19a facing the air intake port 17a is opposed. The shape is located on the fan rotation direction side indicated by the arrow R from the tip Ea (see FIG. 3).

  Here, the cylindrical cross section means a cut surface of a virtual cylinder having a predetermined diameter that is coaxial with the rotation shaft 21, and hereinafter, the term “cylindrical cross section” is used in the same meaning.

  When the centrifugal fan 19 rotates at a high speed in the rotation direction indicated by the arrow R, the external air is located above the centrifugal fan 19 in the direction of the rotation shaft 21 and faces the upper surface of the hub portion 19b. The air is sucked into the inside of the fan casing 22 from both directions of the air inlet 17a provided at the center of the air inlet 17a and the air inlet 18a provided on the bottom surface of the fan frame 18 located below the rotating shaft 21.

  Since the air sucked into the fan casing 22 is changed in the direction of the wind toward the centrifugal direction of the blade portion 19a by the rotational movement of the plurality of blade portions 19a, most of the inner wall of the fan frame 18 or the fan cover 17 is used. The air is sent along the inner wall in the same direction as the direction of rotation indicated by the arrow R of the centrifugal fan 19 and immediately exhausted from the exhaust port 20.

  Further, as shown in FIG. 3, in the centrifugal fan 19, the blade portion 19 a located in the projected area region (see FIG. 5) of the intake ports 17 a and 18 a is along a cylinder having a predetermined radius coaxial with the rotating shaft 21. The pressure surface shape of the cylindrical section of the cut blade portion 19a is the same as that of the member in which the pressure surface tip Eb at the end of the blade portion 19a facing the intake port 17a having a narrower interval with the member disposed in opposition is opposed to the member. The shape is located on the fan rotation direction side of the pressure surface tip Ea at the end portion of the blade portion 19a facing the intake port 18a having the wider interval.

  4A and 4B, the centrifugal fan device 16 includes a hub portion 19b having a cylindrical outer peripheral surface and a radially extending portion 17 from the outer peripheral surface. A centrifugal fan 19 comprising a blade portion 19a and an annular plate 19c formed so as to be continuously connected in a circumferential direction to an end portion located above the blade portion 19a, and an inner center of the hub portion 19b. A rotary shaft 21 that is press-fitted and fixed in a recess of a cylindrical receiving portion 19d formed on the motor, and a motor drive that rotationally drives the centrifugal fan 19 around the rotary shaft 21 under the hub portion 19b. And a fan casing 22 that holds the motor drive unit 23 and accommodates the centrifugal fan 19.

  Here, the motor drive unit 23 is configured by a circuit board in which an electronic circuit for rotationally driving the centrifugal fan 19 around the rotation shaft 21 is built, and the intake air disposed on the bottom surface of the fan frame 18. It is held via two holding portions 18b extending from the fan frame 18 so as to cross the opening 18a in a direction perpendicular to the intake direction.

  That is, the centrifugal fan 19 is covered with the hub portion 19b as described above, and is provided with a rotational driving force in the fan rotation direction indicated by the arrow R by the motor driving portion 23 located below the hub portion 19b. Rotate at high speed.

  The fan cover 17 is connected to the lower fan frame 18 so as to be positioned above the fan frame 18, and the combined fan casing 22 houses the centrifugal fan 19. The outer peripheral portion of 19a is surrounded by the fan casing 22, and the centrifugal fan 22 rotates in the fan rotation direction indicated by the arrow R, so that the static pressure and the air volume necessary for blowing can be generated.

  In FIG. 5, the substantially square fan cover 17 and the fan frame 18 and the two holding portions 18b are indicated by a one-dot chain line, and the intake port 17a (the intake port 18a is also located at the same position) disposed at the center thereof. The rotating shaft 21 located at the chain line and at the center of the centrifugal fan 19 is indicated by a broken line.

  The centrifugal fan 19 includes a plurality of blade portions 19a positioned from the projected area of the intake port 17a to the outside thereof, an annular plate 19c formed on the outer peripheral portion thereof, a hub portion 19b positioned at the center of the blade portion 19a, and the like. These are indicated by solid lines.

  As is clear from this figure, the projected area of the suction port 17 a in the centrifugal fan 19 is a region obtained by projecting the opening portion of the substantially circular suction port 17 a around the rotation shaft 21 in the direction of the centrifugal fan 19. The region is located within the circumference of the intake port 17a indicated by a two-dot chain line.

  Then, in the blade portion 19a located in the projected area of the intake port 17a, which is a region excluding the outer peripheral portion of the centrifugal fan 19, the blade cut along the cylinder having a predetermined radius coaxial with the rotary shaft 21 as described above. The pressure surface shape of the cylindrical cross section of the portion 19a is a member in which the pressure surface tip Eb (see FIG. 3) at the end of the blade portion 19a facing the intake port 17a that is closer to the oppositely disposed member is opposed to the member. And the pressure surface tip Ea (see FIG. 3) at the end portion of the blade portion 19a facing the intake port 18a having the larger interval with the air inlet 18a.

  By adopting the configuration as described above, the centrifugal fan device 16 is arranged in a narrow space, and the air gap resistance balance is ensured by using the same distance from the members arranged opposite to the respective intake ports 17a and 18a. In the case where it is difficult, the suction surface side exceeds the end portion of the blade portion 19a that extends in the radial direction with respect to the end portion of the blade portion 19a that faces the intake port 17a that is closer to the opposingly arranged member. Since the effect of suppressing the air flow that circulates in the air is selectively obtained, as a whole, the sucked air can be efficiently sent out in the centrifugal direction and the air volume can be increased.

  That is, with respect to the air sucked from the intake port 17a on the side where the interval is narrow (the side where the air path resistance is large), the positive pressure surface tip Eb at the end of the blade portion 19a facing the intake port 17a is on the fan rotation direction side. Therefore, it effectively acts on the increase in the air volume, and can carry a sufficient volume of air to the air sucked from the intake port 18a on the side having a large interval (the side having a small air path resistance) ( The pressure surface tip Ea at the end of the blade portion 19a facing the intake port acts in a direction that increases the volume of air in the centrifugal direction, and as a whole, the air is efficiently moved in the centrifugal direction. It can be sent out to increase the air volume.

  In addition, since the air blowing efficiency is improved, it becomes easier to cope with the downsizing / thinning of the centrifugal fan device 16, and as a result, the electronic device 10 mounted with the centrifugal fan device 16 can be easily downsized / thinned. Become.

  Further, as shown in FIG. 6A, the pressure surface tip Eb at the end of the blade portion 19a facing the intake port 17a in at least the projected area of the intake port 17a indicated by the region on the left side of the two-dot chain line. Is more preferably positioned on the fan rotation direction side than the positive pressure surface tip Ea at the end of the blade portion 19a facing the intake port 18a.

  That is, when compared with the region of the outer peripheral portion of the blade portion 19a of the centrifugal fan 19 housed in the fan casing 22, in the projected area region of the substantially circular intake port 17a centering on the rotation shaft 21, the suction port 17a temporarily The air taken into the pressure surface side of the blade portion 19a is not effectively rectified by the fan casing 22, but tends to enter the region from the pressure surface tip Eb of the blade portion 19a toward the suction surface side. Since the action of suppressing the air flow works, the corresponding air flows in the centrifugal direction, and the flow rate of the air substantially increases.

  On the other hand, the region of the outer peripheral portion of the blade portion 19a of the centrifugal fan 19 is surrounded by a fan casing 22 composed of the fan cover 17 and the fan frame 18, and a rectifying action that allows air to flow only in one direction in the centrifugal direction is effective. Therefore, the shape can be set to a desired shape without being restricted by the shape as described above.

  For example, as in the present embodiment, in order to reinforce the mechanical strength of the blade portion 19a and to suppress the generation of turbulent flow in the gap with the fan cover 17 at the outer peripheral portion and fan noise caused by the turbulent flow, The blade portions 19a adjacent to each other can be connected via an annular plate 19c provided at the upper end of the outer peripheral portion.

  As another modification, for example, as shown in FIG. 6B, at least one end located at both ends in the direction of the rotation axis (not shown) in the outer peripheral portion of the blade portion 29a is L. A cutout portion 29e is formed by cutting out into a letter shape, and an annular plate 29c continuously connected in the circumferential direction is integrally formed at an end portion thereof, and upper and lower intake ports 31a of the fan casing 30 are formed. If the edge surrounding 32a is arranged so as to enter the notched portion, it is located in the projected area region of the intake ports 31a, 32a without increasing the height of the outer shape of the centrifugal fan device (not shown). Since the width of the rotating blade portion 29a in the rotation axis direction can be increased, the air volume is further increased.

  As a result, the height of the centrifugal fan device can be made smaller and thinner, and as a result, the electronic device (not shown) mounted with the centrifugal fan device can be made smaller and thinner. It becomes easy.

  Also in this case, at the blade portion 29a located within the projected area of the intake port 31a or the intake port 32a shown in the region on the left side of at least the two-dot chain line, at the end of the blade portion 29a facing the intake port 31a The positive pressure surface tip Eb is more preferably located on the fan rotation direction side than the positive pressure surface tip Ea at the end of the blade portion 29a facing the air inlet 32a, and the same action as described with reference to FIG. Have

  That is, in comparison with the region of the outer peripheral portion of the blade portion 29a of the centrifugal fan housed in the fan casing 30, in the projected area region of the substantially circular intake port 31a centering on the rotation axis, the blade portion is once changed from the intake port 31a. The air taken into the pressure surface side of 29a is not effectively rectified by the fan casing 30, but the air flow that tries to wrap around the region from the pressure surface tip Eb of the blade portion 29a to the suction surface side. Since the effect | action which is suppressed will work | functions, the air of that part flows to the centrifugal direction, and the flow volume of air increases substantially.

  On the other hand, the region of the outer peripheral portion of the blade portion 29a of the centrifugal fan is surrounded by the fan casing 30 including the fan cover 33 and the fan frame 34, and the rectifying action that allows air to flow only in one direction in the centrifugal direction is effective. Since it works, the shape can be set to a desired shape without being restricted by the shape as described above.

  For example, as in this embodiment, in order to reinforce the mechanical strength of the blade portion 29a and to suppress the generation of turbulent flow in the gap with the fan cover at the outer peripheral portion and the fan noise caused by the turbulent flow, The blade portions 29a adjacent to each other can be connected via an annular plate 29c provided at the upper end of the outer peripheral portion.

  Next, as shown in FIG. 7, the hub portion 19b, the blade portion 19a, and the annular plate 19c have sufficient mechanical strength and durability, good formability, and suitable for weight reduction, such as PPS, PBT, and PET. As described above, the blade portion 19a located in the projected area of the intake ports 17a and 18a (see FIG. 5) has a predetermined radius coaxial with the rotary shaft 21. The pressure surface shape of the cylindrical section of the blade portion 19a cut along the cylinder is such that the pressure surface tip Eb at the end portion of the blade portion 19a facing the intake port 17a having a narrower distance from the oppositely disposed member is disposed oppositely. It is shaped to be located on the fan rotation direction side indicated by the arrow R from the positive pressure surface tip Ea at the end of the blade portion 19a facing the intake port 18a having the wider interval with the member.

  Next, FIG. 8A is a cylindrical cross-section obtained by cutting the blade portion 19a along a virtual cylinder having a predetermined diameter that is coaxial with the rotation shaft 21, and shows a cut surface along the arc CC in FIG. The shape is shown.

  As is clear from this figure, the pressure surface shape of the cylindrical cross section of the blade portion 19a is such that the pressure surface tip Eb at the end of the blade portion 19a facing the intake port 17a having a narrower distance from the oppositely arranged member is formed. The shape is located on the fan rotation direction side indicated by the arrow R from the pressure surface tip Ea at the end of the blade portion 19a facing the intake port 18a with the wider space between the opposing members, and from the pressure surface tip Eb. From the central part C in the width direction to a slightly lower side is a substantially flat shape, and from there to the pressure surface tip Ea is a shape slightly inclined toward the rotational direction side indicated by the arrow R.

  Further, the positive pressure surface tip Eb at the end of the blade portion 19a facing the intake port 17a having a smaller interval with the member arranged oppositely faces the blade 18a facing the intake port 18a having a larger interval with the member arranged oppositely. It is only necessary to be located on the fan rotation direction side indicated by the arrow R in FIG. 7 with respect to the pressure surface tip Ea at the end of the portion 19a. As another modification, as shown in FIG. The pressure surface shape of the cylindrical cross section of the blade portion 40a cut along the cylinder of the radius is curved so that both the pressure surface tip Eb and the pressure surface tip Ea are located on the fan rotation direction side indicated by the arrow R from the center portion C. And it is good also as a recessed concave shape.

  Furthermore, as another modified example, as shown in FIG. 8C, the pressure surface shape of the cylindrical section of the blade portion 41a cut along a cylinder having a predetermined radius coaxial with the rotation axis is the pressure surface tip Eb and the pressure surface tip. Any of Ea may be a concave shape that is positioned closer to the fan rotation direction indicated by the arrow R than the center portion C and is linearly recessed like a triangle at the center portion C.

  8A to 8C, the length De of the arc on the same plane between the pressure surface tip Ea and the pressure surface tip Ea is a virtual circle centered on the rotation axis. Is defined to be in the range of 10% to 40% of the width Wb in the direction of the rotation axis of the blade portion, whereby the rotation of the blade portion of the centrifugal fan device Even if the width Wb in the axial direction changes, the suction surface exceeds the end in the rotational axis direction of the blade portion with respect to the end of the blade portion facing the intake port having a narrower distance from the oppositely arranged member. By selectively and appropriately obtaining the effect of suppressing the air flow that circulates to the side, it is possible to efficiently feed the sucked air as a whole in the centrifugal direction and increase the air volume.

  Next, in FIG. 9, when the distance Sb between the inlet having the wider distance between the opposed members and the member is set to Sb = 2.6 mm, the distance between the opposed members is smaller. It is a graph which shows the relationship of the maximum air volume with respect to the space | interval Ss between an inlet port and its member.

  At the time of obtaining this graph, the centrifugal fan 19 has 17 blade portions 19a, the cylindrical cross-sectional shape is the shape shown in FIG. 8A, the maximum outer diameter is 44.0 mm, and the hub portion 19b The maximum outer diameter is 17.2 mm, the maximum width Wb in the direction of the rotating shaft 21 is 8.0 mm, the width in the radial direction of the annular plate 19c is 4.5 mm, and the rotation conditions are 6000 rpm, and they are opposed to each other. When the distance Sb between the air inlet having the wider distance between the flat member and the member is fixed to 2.6 mm, the air inlet having the smaller distance from the flat member disposed opposite to the member and the member The maximum air volume was measured by changing the interval Sa to 1.0 mm, 1.5 mm, and 2.6 mm.

  As a result, as shown in this graph, in the range where the distance Sa exceeds 1.3 mm, which is 50% of the distance Sb, the pressure side of the blade portion is less than that of the conventional flat shape, but the maximum air volume decreases. In the range of 1.3 mm or less where Sa is 50% of the interval Sb, it was confirmed that the maximum air volume tends to increase on the pressure surface side of the blade portion as compared with the conventional flat shape.

  Further, as clearly shown in FIG. 10, the interval Sa at which the maximum air volume starts to increase compared to the blade having the pressure surface side of the conventional flat shape is larger than the intake port having the wider interval with the opposed members. It can be seen that the relationship of 0 <Ss <0.5Sb is satisfied when the distance Sb to the member is in the range of 1.5 mm <Sb <3.0 mm.

  In other words, even if the centrifugal fan device is arranged in a narrower space, the gap between the air inlet and the member having the wider interval between the opposed members and the member is selected in the range of 1.5 mm to 3.5 mm, By selecting the intake port with the narrower interval between the arranged members and the interval between the members up to 50% of the larger interval, the intake with the smaller interval between the opposed members By selectively obtaining the effect of suppressing the air flow that wraps around the suction part side beyond the end part of the blade part that extends in the radial direction with respect to the end part of the blade part that faces the mouth, it is efficient as a whole. The sucked air is sent in the centrifugal direction, and the air volume can be increased.

  In other words, if the distance between the air inlet and the member having a larger distance from the oppositely arranged member and the member is selected in the range of 1.5 mm to 3.5 mm, the distance from the oppositely arranged member is smaller. If the distance between the inlet and the member is 50% or less of the wider distance, the effect of the present invention can be obtained sufficiently.

(Embodiment 2)
Next, in Embodiment 2 of the present invention, a centrifugal fan device having a plurality of blade portions radially about the rotation axis and two upper and lower intake ports of the fan casing of the centrifugal fan device are spaced apart from each other by a predetermined interval. An electronic device having a member disposed opposite to each other, and in particular, a member is not disposed opposite to each other so as to be parallel to each other with a uniform predetermined interval between each of the upper and lower two intake ports. An example in which the present invention is applied in the case where the air path resistances of the spaces between the members arranged opposite to each other in the projected area region on the arranged member side are different from each other will be described.

  Here, FIG. 11A is an explanatory diagram in the case where the interval between one intake port and a member arranged opposite to the intake port is non-uniform, and FIG. 11B shows one intake port. FIG. 11C is an explanatory diagram in the case where the opposing member has an opening through which air can flow, and FIG. 11C is an explanatory diagram in the case where the member opposing the one air inlet has a stepped portion.

  11A to 11C, the fan frame side is described as the upper side, and the fan cover side is described as the lower side.

  First, as shown in FIG. 11A, in the centrifugal fan device 50, the air inlet 51a of the fan cover 51 and the member 52 disposed opposite to the air inlet 51a are parallel, and the interval Sc between them is uniform. However, the air inlet 53a of the fan frame 53 and the member 54 opposed to the air inlet 53a are not parallel, and the air gaps are arranged so that the intervals are not uniform, and the narrowest at the left end. It is installed in the electronic device so that the interval Sd is Sd = Sc and the widest interval Se at the right end is Se> Sd.

  The diameter of the intake port 51a and the diameter of the intake port 53a are substantially the same. As described above, the distance between one intake port 51a and the member 52 disposed opposite to the intake port 51a is at least the other. Since the distance between the air inlet 53a and the member 54 disposed opposite to the air inlet 33a is narrower than the distance between the air flow resistance of the space between the opposed member and 51a, The air path resistance of the space between the arranged members 52 is larger than the air path resistance of the space between the air inlet 53a and the member 54 arranged to face the air inlet 53a.

  Although not shown, the pressure surface shape of the cylindrical section of the blade portion 56a cut along a cylinder having a predetermined radius coaxial with the rotary shaft 55 is the one having the larger air path resistance in the space between the opposing members. The positive pressure surface tip Eb at the end portion of the blade portion 56a facing the air intake port 51a has a cylindrical cross section at the end portion of the blade portion 56a facing the air intake port 53a, which has the smaller air path resistance between the opposing members. It is located on the fan rotation direction side of the positive pressure surface tip Ea.

  Next, as shown in FIG. 11B, the centrifugal fan device 60 includes the space Sf between the air inlet 61 a of the fan cover 61 and the member 62 disposed opposite to the air inlet 61 a and the air intake of the fan frame 63. It is installed in the electronic device so that the distance Sg between the opening 63a and the member 64 disposed so as to face the intake opening 63a is substantially the same and the relationship of Sf = Sg.

  The diameter of the intake port 61a and the diameter of the intake port 63a are substantially the same, but the member 64 is provided with an opening 65 through which air can flow in the area of the projected area of the intake port 63a toward the member 64. Yes.

  Therefore, when compared with the air path resistance of the space between the members arranged opposite to each other, the air path resistance of the space between the air inlet 61a and the member 62 arranged opposite to the air inlet 61a is the other air inlet. It is larger than the air path resistance of the space between 63a and the member 64 disposed opposite to the intake port 63a.

  Although not shown, the pressure surface shape of the cylindrical section of the blade portion 67a cut along a cylinder having a predetermined radius coaxial with the rotation shaft 66 is such that the air path resistance of the space between the opposing members is larger. The positive pressure surface tip Eb at the end of the blade portion 67a facing the air intake 61a has a cylindrical cross section at the end of the blade portion 67a facing the air intake 63a, which has the smaller air path resistance in the space between the opposing members. It is located on the fan rotation direction side of the positive pressure surface tip Ea.

  Next, as shown in FIG. 11C, the centrifugal fan device 70 includes the distance Sh between the air inlet 71 a of the fan cover 71 and the member 72 disposed opposite to the air inlet 71 a, and the air intake of the fan frame 73. It is installed in the electronic device so that the interval Si between the port 73a and the member 74 disposed opposite to the air intake port 73a is substantially the same and has a relationship of Sh = Si.

  The diameter of the intake port 71a and the diameter of the intake port 73a are substantially the same, but the member 74 has at least a distance Sj between the intake port 73a within the projected area of the intake port 73a on the member 74 side and Sj>. A stepped portion 74a is provided so as to have a Si relationship.

  Therefore, when compared with the air path resistance of the space between the members arranged opposite to each other, the air path resistance of the space between the intake port 71a and the member 72 arranged opposite to the intake port 71a is the other air intake port. It is larger than the air path resistance of the space between 73a and the member 74 arranged opposite to the intake port 73a.

  Although not shown, the pressure surface shape of the cylindrical cross section of the blade portion 76a cut along a cylinder having a predetermined radius coaxial with the rotating shaft 75 has a larger air path resistance in the space between the opposing members. The positive pressure surface tip Eb at the end portion of the blade portion 76a facing the intake port 71a has a cylindrical cross section at the end portion of the blade portion 76a facing the intake port 73a, which has the smaller air path resistance in the space between the opposing members. It is located on the fan rotation direction side of the positive pressure surface tip Ea.

  As described above, the centrifugal fan device is arranged in a narrow space, and the members are not arranged to face each other so that the two upper and lower intake ports are parallel to each other with a uniform predetermined interval. If it is difficult to ensure the balance of the air path resistance of the space between the member and the member, for example, it is disposed opposite to the intake port at non-uniform intervals, or an opening that can flow into the member is provided, A step portion is provided on the member, and the air path resistance of the space between the intake port in the projected area region on the member side arranged opposite to each intake port and the member arranged opposite to the intake port is In the case where they are different from each other, the edge of the blade portion facing the intake port having the larger air path resistance in the space between the opposed members is negative beyond the end portion extending in the radial direction of the blade portion. Suppresses airflow that circulates to the pressure side By the effect of obtained selectively, can be increased as a whole, the airflow sent out efficiently sucked air in the centrifugal direction.

  In other words, for the air sucked from the intake port on the side where the air path resistance of the space between the opposed members is large, the tip of the positive pressure surface at the end of the blade portion facing the intake port is in the fan rotation direction. Because it is located on the side, it effectively works against the increase in the air volume, and it has a sufficient volume for air sucked from the air inlet on the side where the air path resistance of the space between the opposed members is small. Since the air volume can be carried (supplied), the tip of the pressure surface at the end of the blade facing the air inlet acts in the direction of increasing the volume of air that is carried in the centrifugal direction. The amount of air can be increased by feeding in the centrifugal direction.

  In addition, since the air blowing efficiency is improved, it becomes easier to cope with the downsizing and thinning of the centrifugal fan device, and as a result, the electronic device mounted with the centrifugal fan device can be easily downsized and thinned.

  In the above description of the second embodiment, only typical ones have been described. However, the size and shape of each intake port of the centrifugal fan device, and the positional relationship with the members disposed opposite to the intake port, Furthermore, the shape and arrangement of the member itself vary depending on the electronic device on which the centrifugal fan device is mounted.

  Therefore, in order to determine whether or not the airflow resistance in the space between each intake port and a member arranged opposite to the intake port is different from each other, only one of the intake ports is simply blocked. If the air volume blown out from the exhaust port of the centrifugal fan device in this case is compared with the air amount blown out from the exhaust port of the centrifugal fan device when only the other air intake port is blocked, It is also possible to determine that the air path resistance in the space between the air intake port closed in FIG.

  As described above, according to the electronic apparatus of the present invention, the centrifugal fan device is arranged in a narrow space, and the air path resistance of the space between them is made the same with the members arranged opposite to the respective intake ports. Even when it is difficult to ensure the balance, it is negative with respect to the end of the blade facing the air inlet with the narrower distance from the oppositely arranged member, beyond the end extending in the radial direction of the blade. By selectively obtaining the effect of suppressing the air flow that circulates to the pressure surface side, as a whole, the sucked air can be efficiently sent out in the centrifugal direction and the air volume can be increased.

  As a result, the cooling performance for the heating element is improved, and it becomes easier to take measures against heat generation when heat generating electronic components such as MPUs and CPUs driven at a higher clock frequency are mounted. Can promote.

  In addition, since the flow rate in the centrifugal direction is increased, air flow and static pressure can be easily increased, so that the air blowing efficiency can be improved and the centrifugal fan device can be made smaller and thinner. In addition to facilitating layout design in the body, it is easy to cope with thinning and miniaturization of the casing of an electronic device in which the centrifugal fan device is mounted.

  In the description of the above embodiments, the dimensions, quantities, materials, shapes, relative arrangements, etc. of the respective components are within the scope of the present invention unless otherwise specified. The present invention is not intended to be limited to these, but merely an explanation of one embodiment, and various modifications are possible.

  For example, the shape of the blade part is not particularly limited, and is vertically asymmetric in the direction of the rotation axis, or the width and thickness of the blade part in the direction of the rotation axis are uniform from the inner diameter side to the outer diameter side. The shape in the direction orthogonal to the axis may be a shape that is not straight but curved or meanders on the inner diameter side, outer diameter side, or an intermediate portion thereof.

  The centrifugal fan may be any centrifugal fan that has a plurality of blade portions and blows air in the centrifugal direction by the rotation of the blade portions. For example, a plurality of blade portions such as a sirocco fan or a cross flow fan are formed on the main plate. It may be a centrifugal fan having a form formed only on the outer periphery.

  Also, the outer shape of the fan casing is not particularly limited, and may be a substantially circular shape, a substantially triangular shape, a substantially rectangular shape, a substantially parallelogram shape, or other various polygonal shapes. You may provide in the direction or three or more directions.

  In addition, the fan casing is not simply composed of a cover and a frame, but a heat receiving part for making a thermal connection with a heat-generating electronic component is provided on a part of the cover or the frame, or heat dissipation is improved. A heat sink composed of heat-dissipating fins may be integrally provided by die casting or press molding, and a heat transport member such as a heat pipe or a heat conductive sheet that efficiently conducts heat transport between them may be used. You may have.

  In addition, it is preferable to integrally form the cover and frame constituting the fan casing by press molding using a metal material having good thermal conductivity, which can reduce the manufacturing cost. However, other methods such as die casting, forging, and extrusion molding may be used. An integral molding method may be adopted, and when it is difficult to perform integral molding due to layout design in the housing of the electronic device, they are manufactured separately and configured by a predetermined assembly process. It doesn't matter.

  Furthermore, if a metal material with good thermal conductivity is selected as the molding material for the fan casing and related members, it is preferable because the thermal diffusion effect in those members can be obtained and the heat dissipation performance can be improved. In the case where a lighter weight is desired while being obtained, those constituent elements may be made of a resin molding material.

  An electronic apparatus according to the present invention has a heating element such as an MPU mounted inside a casing, such as a mobile-compatible notebook computer or DVD player that is required to be smaller or thinner. The present invention can be applied to an electronic device provided with a centrifugal fan device that blows and cools.

(A) The figure which showed the inside of the housing | casing of the electronic device in Embodiment 1 of this invention, (b) Sectional drawing which showed the principal part of the figure (a) The perspective view from the upper part of the centrifugal fan apparatus in Embodiment 1 of this invention The perspective view from the upper part of the centrifugal fan in Embodiment 1 of this invention (A) The top view of the centrifugal fan apparatus in Embodiment 1 of this invention, (b) The sectional view on the AA arrow of the same figure (a). The top view of the centrifugal fan in Embodiment 1 of this invention (A) BB arrow sectional drawing of FIG. 5, (b) Sectional drawing which shows the modification of the figure (a) The partial expansion perspective view of the centrifugal fan in Embodiment 1 of this invention (A) CC sectional view of the blade part of FIG. 7, (b) Cross sectional view showing a modification of FIG. 7 (a), (c) Cross sectional view showing a modification of FIG. The graph which shows the relationship of the largest airflow with respect to the space | interval Sa with the air inlet which has a space | interval with the member arrange | positioned facing opposite, and its member The graph which shows the relationship of the space | interval Sa from which the air volume with respect to the space | interval Sb of the air inlet which has a space | interval with the member arrange | positioned oppositely, and the member begins to increase rather than the conventional flat shape. (A) Explanatory drawing when the space | interval of one inlet and the member arrange | positioned facing the inlet is non-uniform | heterogenous, (b) The opening which the member arrange | positioned facing one inlet can allow air to flow in Explanatory drawing in the case of having a portion, (c) Explanatory drawing in the case where a member disposed opposite to one intake port has a stepped portion Perspective view of centrifugal fan described in (Patent Document 1) (A) DD sectional view of the blade part of FIG. 12, (b) Cross sectional view showing a modification of FIG. 12 (a), (c) Cross sectional view showing a modification of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Liquid crystal display device 11 Main body apparatus 11a Case side wall 11b Case bottom wall 11c Vent hole 11d Case side wall 11e Vent hole 11f Vent hole 12 Hinge mechanism 13 Electronic device 14 Circuit board 15 Heat sink 16 Centrifugal fan device 17 Fan cover 17a Inlet port 18 Fan frame 18a Intake port 18b Holding part 19 Centrifugal fan 19a Blade part 19b Hub part 19c Ring plate 19d Cylindrical receiving part 19e Notch part 20 Exhaust port 21 Rotating shaft 22 Fan casing 23 Motor drive part 29a Blade part 29c Ring Plate 29e Notch 30 Fan casing 31a Inlet port 32a Inlet port 33 Fan cover 34 Fan frame 40a Blade unit 41a Blade unit 51 Fan cover 51a Inlet port 52 Member 53 Fan frame 53a Inlet air Port 54 Member 55 Rotating shaft 56a Blade portion 60 Centrifugal fan device 61 Fan cover 61a Air inlet 62 Member 63 Fan frame 63a Air inlet 64 Member 65 Opening 66 Rotating shaft 67a Blade portion 70 Centrifugal fan device 71 Fan cover 71a Air inlet 72 Member 73 Fan frame 73a Inlet port 74 Member 75 Rotating shaft 76a Blade part R Fan rotation direction De Arc length Ea Positive pressure surface tip Eb Positive pressure surface tip Sa, Sb, Sc, Sd, Se, Sf, Sg, Sh, Si, Sj interval

Claims (6)

A centrifugal fan device having a plurality of blade portions radially about a rotating shaft and a member disposed opposite to each other so as to be parallel to each other at two uniform upper and lower intake ports of the fan casing of the centrifugal fan device The interval between the one intake port and the member arranged opposite to the intake port is smaller than the interval between the other intake port and the member arranged opposite to the intake port, The pressure surface shape of the cylindrical section of the blade portion cut along a cylinder having a predetermined radius coaxial with the rotation shaft is formed at the end portion of the blade portion facing the intake port having a narrower distance from the opposed member. An electronic device having a shape positioned on the fan rotation direction side of the front end of the pressure surface at the end of the blade portion facing the intake port having the wider space between the front end of the positive pressure surface and the member disposed oppositely An electronic apparatus comprising: a centrifugal fan device having a plurality of blade portions radially about a rotation axis; and a member disposed oppositely to each of two upper and lower intake ports of a fan casing of the centrifugal fan device with a predetermined interval therebetween. The air path resistance of the space sandwiched between one intake port and the member disposed opposite to the intake port is the air path resistance of the space sandwiched between the other intake port and the member disposed opposite to the intake port. The pressure surface shape of the cylindrical section of the blade portion cut along a cylinder having a predetermined radius that is smaller than the resistance and coaxial with the rotation axis is larger in the air path resistance of the space between the opposing members. The fan has a lower air path resistance than the pressure surface tip at the end of the blade part facing the air inlet, and the air path resistance of the space between the end of the blade part facing the air inlet and the member opposed to the member facing the air inlet is smaller. In the direction of rotation Electronic apparatus, characterized in that the location for the shape. In the case where the distance between the air inlet having the wider distance between the opposed member and the member is Sb, and the distance between the air inlet having the smaller distance from the opposite member and the member is Sa, 2. The electronic apparatus according to claim 1, wherein a relationship of 0.5 mm <Sb <3.5 mm and 0 <Sa <0.5Sb is satisfied. At the end of the blade part facing the air inlet with the larger distance between the front end of the pressure surface at the end of the blade part facing the air inlet with the narrower distance to the member arranged oppositely 2. The electronic apparatus according to claim 1, wherein the length of the arc on the same plane between the tip of the pressure surface is in the range of 10% to 40% of the width of the blade portion in the rotation axis direction. . In the blade part located in the projected area region of the intake port, the pressure surface shape of the cylindrical section of the blade part cut along a cylinder having a predetermined radius coaxial with the rotation axis, the tip of the pressure surface on both sides is the central part The electronic device according to claim 1, wherein the electronic device has a concave shape located closer to the fan rotation direction. In the outer peripheral part of the blade part, at least one end part located at both end parts in the rotation axis direction is cut out so that the edge part surrounding the air inlet of the fan casing enters the cut out part. The electronic apparatus according to claim 1, wherein the electronic apparatus is disposed in a position.

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