JP2011047347A - Blowing fan - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a blowing fan having a structure enhanced in the cooling effect of a circuit board. <P>SOLUTION: The blowing fan 100 includes: an almost cylindrical impeller cup 11 rotating about a rotation axis J; a plurality of blades 12 fixed to the outer peripheral face of the impeller cup 11 and rotating with the impeller cup 11 to take in air from one side in the axial direction and discharge the air to the other side in the axial direction; a base part 15 rotatably supporting the impeller cup 11 via a bearing part 14; and the circuit board 21 arranged on an air intake side to the base part 15. The base part 15 has at the peripheral end a peripheral wall 16 extending to the air intake side in the axial direction. The peripheral wall 16 is formed at parts thereof with projecting portions 17 each having an inner peripheral face 17a recessed outward in a radial direction and opened on the air intake side in the axial direction. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a blower fan used for cooling an electronic device.

  A conventional blower fan has a configuration in which an impeller provided with a plurality of blades is rotated by a motor disposed in a cylindrical impeller cup. A circuit board for controlling the rotation of the motor is disposed in the motor, but the outer periphery of the circuit board is radially outward from the outer periphery of the impeller cup so as not to hinder the air flow generated by the rotation of the impeller. It is arranged so as not to protrude. On the other hand, since the air flow generated by the rotation of the impeller is directed radially outward by the centrifugal force, almost no air flows through the circuit board disposed radially inward of the impeller cup. Therefore, when the rotational load of the motor increases and the heat generation of the electronic components mounted on the circuit board increases, there arises a problem that the temperature of the circuit board rises.

In order to solve such a problem, Japanese Patent Application Laid-Open No. 2004-319949 discloses that a heat dissipation film is formed on the outer peripheral portion of a circuit board, and an electronic component (heat generating element) is connected to the heat dissipation film, thereby being generated from the electronic component. A technique for releasing the heat generated through the heat dissipation film is described. In addition, a technique is described in which the heat dissipation effect is further improved by projecting the heat dissipation film radially outward from the outer periphery of the impeller cup (hub).
JP 2004-319949 A

  However, in the technique described in Japanese Patent Application Laid-Open No. 2004-319949, the action of guiding the air flow generated by the rotation of the impeller radially inward does not work, so the heat dissipation film formed on the outer peripheral portion of the circuit board Almost no air hits it. Therefore, the heat dissipation effect by the heat dissipation film is not sufficiently exhibited. In particular, as the blower fan is miniaturized, if the circuit board is mounted with high density, the amount of heat generated by the electronic component increases, and a new cooling means is required. In addition, a cooling effect can be given by the air flow generated by the rotation of the impeller by projecting the heat radiation film radially outward from the outer periphery of the impeller cup (hub), but the air flow is obstructed. Therefore, there arises a problem that the fan characteristics are deteriorated. In addition, since it is necessary to form a heat dissipation film on the circuit board and to connect an electronic component (heat generating element) to the heat dissipation film, the cost is increased.

  This invention is made | formed in view of this point, and it aims at providing the ventilation fan which has a structure which improved the cooling effect of the circuit board.

  In order to solve the above-described problems, the present invention provides a base portion that rotatably supports an impeller cup via a bearing portion, and a part of a peripheral wall provided at a peripheral end portion of the base portion has an inner peripheral surface thereof. Adopts a configuration in which a protrusion is formed which is recessed outward in the radial direction and the axial intake side is open.

  That is, the blower fan according to one aspect of the present invention is fixed to the substantially cylindrical impeller cup that rotates about the rotation shaft and the outer peripheral surface of the impeller cup, and rotates together with the impeller cup so that the blower fan can be A plurality of blades that inhale and exhaust to the other side in the axial direction, a base part that rotatably supports the impeller cup via a bearing part, and a circuit board disposed on the intake side with respect to the base part The base portion has a peripheral wall extending to the axial intake side at the peripheral end, and the inner peripheral surface of the peripheral wall is recessed radially outward and the axial intake side is opened. A protrusion is formed.

  With such a configuration, the air flow generated by the rotation of the blades is actively guided radially inward, that is, to the circuit board side from the protrusion provided on a part of the peripheral wall of the base part, thereby the circuit board and the stator. The coil of the part can be cooled effectively. Further, since the air flow is actively guided inward in the radial direction, the air also flows below the circuit board, so that a cooling effect can be exerted even on the circuit board mounted on one side. In addition, since the protrusion provided on a part of the base portion peripheral wall can be formed integrally with the base portion, the cost does not increase.

  In a preferred embodiment, the outer diameter of the peripheral wall of the base portion and the outer diameter of the outer peripheral portion of the impeller cup are substantially the same size, and the inner peripheral surface of the protrusion is more than the outer peripheral surface of the impeller cup. Located radially outward. Moreover, it is preferable that a plurality of projecting portions are formed in the circumferential direction of the base portion peripheral wall. As a result, the air flow generated by the rotation of the blade can be guided radially inward from the protrusion without substantially obstructing the air flow generated by the rotation of the blade.

  In another preferred embodiment, the edge portion on the rotational direction side of the blade constitutes a so-called forward wing-shaped blade in which the radially outer side protrudes toward the rotational direction side than the radially inner side. Yes. As a result, a sufficient amount of airflow can be obtained even in the vicinity of the outer peripheral surface of the impeller cup. Therefore, the cooling effect of the circuit board or the like can be further improved by guiding more airflow radially inward from the protrusion.

  ADVANTAGE OF THE INVENTION According to this invention, the ventilation fan which makes | forms the structure excellent in the cooling effect of a circuit board etc. is realizable.

It is sectional drawing which showed typically the structure of the ventilation fan in one Embodiment of this invention. (A) is the top view which looked at the bottom part of the base part, the housing, and the rib from the upper part, (b) is sectional drawing along AA of (a). It is the top view which showed the shape of the protrusion part in a 1st modification. (A) is the top view which showed the shape of the protrusion part in a 2nd modification, (b) is the perspective view which expanded and showed the vicinity of the protrusion part. It is the perspective view which showed the shape of the protrusion part in a 3rd modification. (A) is the top view which showed the shape of the protrusion part in a 4th modification, (b) is the perspective view which expanded and showed the vicinity of the protrusion part. It is the perspective view which expanded and showed a part of base part surrounding wall. It is the top view seen from the bottom part of a base part, a circuit board, a housing, and a rib.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the description of the present embodiment, the direction parallel to the rotation axis is referred to as “axial direction”, and the radial direction around the rotation axis is referred to as “radial direction”. The present invention is not limited to the following embodiment. Moreover, it can change suitably in the range which does not deviate from the range which has the effect of this invention. Furthermore, combinations with other embodiments are possible.

  FIG. 1 is a cross-sectional view schematically showing a configuration of a blower fan 100 according to an embodiment of the present invention. In addition, the ventilation fan 100 in this invention comprises what is called an axial flow fan.

  As shown in FIG. 1, by rotating together with the impeller cup 11 on the outer peripheral surface of a substantially covered cylindrical impeller cup 11 that rotates about a rotation axis J, air is sucked from one side in the axial direction and the other side in the axial direction. A plurality of blades 12 to be exhausted are fixed. In the following description, for the sake of convenience, the axial intake side is referred to as “upward” and the axial exhaust side is referred to as “downward”.

  A shaft 13 protruding downward is fixed to the center portion of the impeller cup 11. The shaft 13 is inserted into a bearing portion 14 formed of a sleeve and is rotatably supported by the base portion 15 via the bearing portion 14. ing. A circuit board 21 is disposed above the base portion 15, and a stator section 18 is disposed above the circuit board 21. Here, the stator portion 18 is fixed to the outer peripheral surface of a cylindrical portion (bearing holding portion) protruding upward from the bottom portion of the base portion 15. A substantially cylindrical metal rotor holder 19 is fixed to the inner peripheral surface of the impeller cup 11, and a field magnet 20 is fixed to the inside of the side wall portion of the rotor holder 19. Further, the base portion 15 is fixed to the housing 22 via a plurality of ribs 23.

  Here, instead of being fixed to the impeller cup 11, the shaft 13 may be fixed to the central portion of the rotor holder 19 after the rotor holder 19 is configured in a substantially covered cylindrical shape. Further, the bearing holding portion that fixes the bearing portion 14 and the stator portion 18 may not be formed integrally with the base portion 15.

  2A is a plan view of the bottom portion of the base portion 15, the housing 22, and the rib 23 as viewed from above, and FIG. 2B is a cross-sectional view taken along line AA in FIG. 2A. is there.

  As shown in FIGS. 1 and 2 (a) and 2 (b), the base portion 15 has a peripheral wall 16 extending toward the axial intake side (upward) at the peripheral end, and a portion of the peripheral wall 16 includes The inner peripheral surface 17a is recessed outward in the radial direction, and a protruding portion 17 is formed in which the axial suction side (upper side) is opened.

  Here, as shown in FIG. 1, the outer diameter of the peripheral wall 16 of the base portion 15 and the outer diameter of the outer peripheral portion of the impeller cup 11 are substantially the same, and the inner peripheral surface 17a of the protruding portion 17 is an impeller cup. 11 is located radially outward from the outer peripheral surface of 11. As a result, the outer peripheral portion of the circuit board 21 is disposed with a gap between at least the protruding portion 17.

  By configuring the projecting portion 17 in this way, a part of the air flow generated in the axial direction by the rotation of the blade 12 hits the inner peripheral surface 17a of the projecting portion 17, so that the projecting portion 17 is radially inward. That is, it is positively guided to the circuit board 21 side. Thereby, the coil of the circuit board 21 and the stator part 18 arrange | positioned in the radial direction inside of the impeller cup 11 can be cooled effectively. Further, since the outer peripheral portion of the circuit board 21 has a gap between the protruding portion 17, the air guided radially inward also flows below the circuit board 21. Therefore, the cooling effect can be exerted also on the so-called single-sided circuit board 21 in which electronic components are mounted only on the lower surface of the circuit board 21. Moreover, since the protrusion part 17 provided in a part of base part surrounding wall 16 can be integrally formed with the base part 15, a cost increase does not arise.

  Here, by disposing the circuit board 21 on the exhaust side (downward) in the axial direction with respect to the protruding portion 17, the lower end portion of the stator portion 18 can be relatively brought closer to the protruding portion 17. Thereby, the coil of the stator part 18 can be cooled more effectively.

  The protrusions 17 in the present invention actively guide the air flow generated by the rotation of the blades 12 to the circuit board 21 side. Therefore, if a plurality of protrusions 17 are formed in the circumferential direction of the base peripheral wall 16, a sufficient cooling effect is obtained. Can demonstrate. Therefore, even if the protrusion 17 that protrudes radially outward from the outer peripheral surface of the impeller cup 11 is provided, the air flow generated by the rotation of the blade 12 is hardly inhibited.

  In addition, the number of the protrusions 17 is not particularly limited, and may be appropriately determined according to the required cooling performance. Moreover, if the some protrusion part 17 formed in the circumferential direction of the base part surrounding wall 16 is formed between the ribs 23 which connect the base part 15 and the housing 22, as shown in FIG.1 and FIG.2, for example, The base portion peripheral wall 16 can be arranged at equal intervals in the circumferential direction. Thereby, since an airflow can be uniformly guide | induced to the outer peripheral part of the circuit board 21, the circuit board 21 can be cooled equally.

  In the present invention, the outer diameter of the peripheral wall 16 of the base portion 15 and the outer diameter of the outer peripheral portion of the impeller cup 11 are preferably substantially the same. Of course, the air flow generated by the rotation of the blades 12 is the same. The outer diameter of the peripheral wall 16 of the base portion 15 may be larger than the outer diameter of the outer peripheral portion of the impeller cup 11 so as not to be hindered.

  In addition, as shown in FIG. 1, even if the outer peripheral portion of the circuit board 21 is in contact with the inner peripheral surface of the base portion peripheral wall 16, the effect of the present invention can be exhibited. It may be separated from the inner peripheral surface of the base portion peripheral wall 16.

  The shape of the protrusion 17 in the present invention is not particularly limited. For example, as shown in FIG. 2B, the inner peripheral surface 17a of the protrusion 17 is directed toward the exhaust side (downward) as it goes radially inward. It is preferable to have an inclined surface inclined. By having such an inclined surface, it becomes possible to guide the air flow generated by the rotation of the blades 12 to the circuit board 21 side more smoothly.

  By the way, the blower fan 100 having the configuration shown in FIG. 1 generates an air flow from the axial intake side to the exhaust side as a whole by the rotation of the blades 12. It works to face the direction. Therefore, the air flow in the vicinity of the outer peripheral portion of the impeller cup 11 has a smaller flow rate than the air flow in the radially outward direction of the impeller cup 11. Thus, by forming the blade 12 into a so-called forward blade shape, the air flow acts inward in the radial direction, so that the air flow rate in the vicinity of the outer peripheral portion of the impeller cup 11 can be increased. Thereby, since more airflow can be guide | induced to the circuit board 21 side from the protrusion part 17, the cooling effect of the circuit board 21 grade | etc., Can further be improved. Here, the advancing blade shape refers to a shape in which the edge of the blade 12 on the rotational direction side is positioned on the rotational direction side on the radially outer side than on the radially inner side.

  In the present invention, by forming the projecting portion 17 in the circumferential direction of the base portion peripheral wall 16, a part of the air flow generated by the rotation of the blade 12 is positively guided inward in the radial direction of the base portion peripheral wall 16. It is a thing. Therefore, by devising the shape of the protrusion 17, it is possible to more efficiently guide the air flow radially inward. Hereinafter, various modified examples of the shape of the protruding portion 17 will be described with reference to FIGS.

  FIG. 3 is a plan view showing the shape of the protrusion 17 in the first modification. As shown in FIG. 3, the projecting portion 17 in the present modification includes a side portion 17 b on the rotation direction (arrow direction in the drawing) side of the blade 12 (not shown) on both sides in the circumferential direction of the projecting portion 17. It has a shape that is inclined inward in the radial direction as it goes to the rotational direction side. The air flow generated by the rotation of the blades 12 has a swirl component in the rotation direction. Therefore, a larger amount of airflow can be applied to the inner peripheral surface of the protrusion 17 by enlarging the area of the side portion 17b on the rotation direction side of the protrusion 17. As a result, a larger amount of airflow can be taken into the inside from the outside of the base portion 15.

  FIG. 4A is a plan view showing the shape of the protrusion 17 in the second modification, and FIG. 4B is a perspective view showing the vicinity of the protrusion 17 in an enlarged manner. As shown in FIG. 4A, the protrusion 17 in the present modification is a side portion on the rotation direction (arrow direction in the drawing) side of the blade 12 (not shown) among the circumferential side portions of the protrusion 17. 17b is in contact with the rib 23, and as shown in FIG. 4B, the axial height L2 of the rib 23 is higher than the axial height L1 of the circumferential side portion of the protruding portion 17. It has a shape. As a result, the swirl component of the air flow hits the side wall of the rib 23, so that a larger amount of air flow can be applied to the inner peripheral surface of the protruding portion 17 in contact with the rib 23. As a result, a larger amount of airflow can be taken into the inside from the outside of the base portion 15.

  FIG. 5 is a perspective view showing the shape of the protrusion 17 in the third modification. As shown in FIG. 5, the projecting portion 17 in the present modification is such that the axial height L <b> 1 of the peripheral wall 16 at the portion where the projecting portion 17 of the base portion 15 is formed is the peripheral wall at the portion where the projecting portion 17 is not formed. It has a shape higher than 16 axial heights L3. In addition, it is preferable that the inner peripheral surface 17a of the protrusion 17 has an inclined surface that inclines toward the exhaust side (downward) as it goes inward in the radial direction, as shown in FIG. 2 (b). . Thereby, since the area of the inner peripheral surface 17a of the protrusion 17 is enlarged, a larger amount of airflow can be taken in from the protrusion 17.

  FIG. 6A is a plan view showing the shape of the protrusion 17 in the fourth modified example, and FIG. 6B is an enlarged perspective view showing the vicinity of the protrusion 17. As shown in FIGS. 6A and 6B, the protrusion 17 in the present modification is the rotational direction of the blade 12 (not shown) in the circumferential side portion of the protrusion 17 (the arrow direction in the figure). The side portion 17c located on the upstream side is open. As a result, the swirl component of the airflow flowing in the vicinity of the base portion peripheral wall 16 is not blocked by the side portion of the projecting portion 17, so that a larger amount of airflow can be taken in.

  As described above, by making the protrusions 17 into various shapes, a large amount of airflow can be taken into the circuit board 21 side. However, in order to further enhance the cooling effect of the circuit board 21, it is taken in. It is desirable to release the air to the outside again. Therefore, as shown in FIG. 7, it is preferable to form an opening 16 a in a part of the base portion peripheral wall 16. Thereby, the air taken in from the protrusion 17 to the circuit board 21 side can be discharged to the outside from the opening 16a after the circuit board 21 is cooled.

  Here, the shape of the opening 16a is not particularly limited, but may be, for example, a slit or a hole. Further, when the base portion 15 is formed by resin molding, the slits 16a can be easily formed at the end portion on the opposite side to the open end of the base portion peripheral wall 16, as shown in FIG.

  FIG. 8 is a plan view of the bottom portion of the base portion 15, the circuit board 21, the housing 22, and the rib 23 as viewed from above. As shown in FIG. 8, a portion 21 a protruding outward in the radial direction may be provided on the outer peripheral portion of the circuit board 21 at a position facing the inner peripheral surface of the protruding portion 17. Thereby, alignment with the circuit board 21 and the base part 15 can be performed easily. In FIG. 8, the outer peripheral portion of the circuit board 21 is disposed away from the base portion peripheral wall 16. However, as shown in FIG. 1, the outer peripheral portion of the circuit board 21 is, of course, the base portion peripheral wall 16. It may be arranged in contact with. In this case, the portion 21 a protruding outward in the radial direction of the circuit board needs to be disposed with a gap between the protruding portion 17.

  As mentioned above, although this invention was demonstrated by suitable embodiment, such description is not a limitation matter and of course various modifications are possible. For example, in the above embodiment, an oil-impregnated bearing made of a sleeve is used for the bearing portion 14, but a ball bearing may be used.

DESCRIPTION OF SYMBOLS 11 Impeller cup 12 Blade | wing 13 Shaft 14 Bearing part 15 Base part 16 Base part surrounding wall 16a Opening part (slit)
17 Protruding part 17a Protruding part inner peripheral surface 17b Protruding part side part 17c Protruding part side part 18 Stator part 19 Rotor holder 20 Field magnet 21 Circuit board 21a Projecting part of circuit board 22 Housing 23 Rib 100 Blower fan

Claims (15)

A substantially cylindrical impeller cup that rotates about a rotation axis;
A plurality of blades that are fixed to the outer peripheral surface of the impeller cup and rotate together with the impeller cup, thereby sucking air from one side in the axial direction and exhausting the other side in the axial direction;
A base portion that rotatably supports the impeller cup via a bearing portion;
A circuit board disposed on the intake side with respect to the base portion,
The base portion has a peripheral wall extending toward the axial intake side at the peripheral end portion,
A blower fan, wherein an inner peripheral surface of the peripheral wall is recessed outward in the radial direction, and a protruding portion having an open axial suction side is formed. The blower fan according to claim 1,
The outer diameter of the peripheral wall of the base portion and the outer diameter of the outer peripheral portion of the impeller cup are substantially the same size,
The blower fan, wherein an inner peripheral surface of the protruding portion is positioned radially outward from an outer peripheral surface of the impeller cup. The blower fan according to claim 1,
An edge of the blade in the rotational direction side is a blower fan having a shape in which the radially outer side is located on the rotational direction side rather than the radially inner side. The blower fan according to claim 1,
A plurality of the projecting portions are formed in the circumferential direction of the base portion peripheral wall. The blower fan according to claim 1,
A housing that covers the plurality of blades from the radially outer side;
A plurality of ribs connecting the base portion and the housing;
The protrusion is a blower fan formed between the ribs. In the ventilation fan of Claim 1,
The blower fan, wherein the inner peripheral surface of the protrusion has an inclined surface that is inclined toward the exhaust side as it goes radially inward. The blower fan according to claim 1,
Of the both sides in the circumferential direction of the projecting portion, the side of the blade in the rotational direction is inclined toward the radially inward as it goes to the rotational direction. In the ventilation fan of Claim 5,
Of the circumferential side portions of the protruding portion, the side portion on the rotational direction side of the blade is in contact with the rib,
The blower fan, wherein an axial height of the rib is higher than an axial height of a circumferential side portion of the protrusion. In the ventilation fan of Claim 1,
The blower fan in which the axial height of the peripheral wall in the portion where the protruding portion of the base portion is formed is higher than the axial height of the peripheral wall in the portion where the protruding portion is not formed. The ventilation fan of Claim 1 WHEREIN: The ventilation fan with which the side part on the rotation direction opposite side of the said blade | wing is opened among the circumferential direction side parts of the said protrusion part. The blower fan according to claim 1,
The blower fan, wherein the outer peripheral portion of the circuit board is disposed with a gap between at least the protruding portion. The blower fan according to claim 1,
A stator portion is disposed on the intake side with respect to the circuit board,
The said circuit board is a ventilation fan arrange | positioned with respect to the said protrusion part at the axial direction exhaust side. In the ventilation fan of Claim 1,
A blower fan in which a slit or a hole is formed in a part of the peripheral wall of the base portion. The blower fan according to claim 13,
The said slit is a ventilation fan currently formed in the edge part on the opposite side with respect to the open end of the said surrounding wall. The blower fan according to claim 1,
A blower fan, wherein a portion projecting radially outward is provided on the outer peripheral portion of the circuit board at a position facing the inner peripheral surface of the projecting portion.

Images