U.S. patent application number 12/826173 was filed with the patent office on 2010-12-02 for miniature heat-dissipating fan device.
This patent application is currently assigned to Industrial Technology Research Institute. Invention is credited to Chan-Hsing Lo, Wen-Yang Peng, Tung-Chuan Wu.
Application Number | 20100303652 12/826173 |
Document ID | / |
Family ID | 43220447 |
Filed Date | 2010-12-02 |
United States Patent
Application |
20100303652 |
Kind Code |
A1 |
Peng; Wen-Yang ; et
al. |
December 2, 2010 |
MINIATURE HEAT-DISSIPATING FAN DEVICE
Abstract
A miniature heat-dissipating fan device is disclosed, which
comprises: a frame; a shaft, pivotally connected to the frame; at
least a planar coil, each being received in the frame and formed in
a wave winding manner; at least a permanent magnet, each being
connected to the shaft while being positioned about parallel to the
at least one planar coil for enabling the generation of an
alternating multipolar magnetic field; a plurality of blades, being
disposed at positions corresponding to the at least one permanent
magnet while centering around the axis of the shaft in a
centrifugal manner; and at least a magnetically permeable back
iron, disposed at a side of the at least one planar coil and being
structured with a geometrical shape matching to the wave winding
planar coil; wherein the plural blades are integrated with the at
least one permanent magnet for enabling the same to rotate with the
at least one permanent magnet synchronously. In an exemplary
embodiment of the invention, the planar coil is structured with at
least a hollowed area, each having a Hall-effect sensor embedded
therein. With the aforesaid device, not only it can be structured
as a thin-type device with improved convection efficiency, but also
the magnetic flux density is increased.
Inventors: |
Peng; Wen-Yang; (Hsinchu
County, TW) ; Wu; Tung-Chuan; (Hsinchu City, TW)
; Lo; Chan-Hsing; (Hsinchu County, TW) |
Correspondence
Address: |
WPAT, PC;INTELLECTUAL PROPERTY ATTORNEYS
7225 BEVERLY ST.
ANNANDALE
VA
22003
US
|
Assignee: |
Industrial Technology Research
Institute
Hsinchu
TW
|
Family ID: |
43220447 |
Appl. No.: |
12/826173 |
Filed: |
June 29, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11834162 |
Aug 6, 2007 |
|
|
|
12826173 |
|
|
|
|
Current U.S.
Class: |
417/423.1 |
Current CPC
Class: |
H02K 9/06 20130101; H02K
21/24 20130101; H02K 1/2793 20130101; H02K 2211/03 20130101; F04D
17/16 20130101; H02K 3/26 20130101; F04D 25/0653 20130101 |
Class at
Publication: |
417/423.1 |
International
Class: |
F04D 25/02 20060101
F04D025/02 |
Foreign Application Data
Date |
Code |
Application Number |
May 10, 2007 |
TW |
096116579 |
Claims
1. A miniature heat-dissipating fan device, comprising: a frame; a
shaft, pivotally connected to the frame; at least a planar coil,
each being received in the frame and formed in a wave winding
manner; at least a permanent magnet, each being connected to the
shaft while being positioned about parallel to the at least one
planar coil for enabling the generation of an alternating
multipolar magnetic field; a plurality of blades, being disposed in
a manner that each is coupled to the at least one permanent magnet
so as to rotate with the at least one permanent magnet
synchronously; and at least a magnetically permeable back iron,
each being disposed at a side of the at least one planar coil and
being structured with a geometrical shape matching to the wave
winding planar coil; wherein the planar coil comprises at least one
layer of coil being wound on a same level, and on such level, said
layer is formed by a plurality of turns of coil which is formed by
continuous wire wound symmetrically around the radial center of the
planar coil, each turn of coil has a plurality of convex pole
portion and corresponding concave pole portion, the convex pole
portion and the corresponding concave pole portion consists of a
arc section and two line sections, the center of the arc section is
the radial center which is also the center the two line sections
radially pointing to virtually, and each line section is
common-owned by the adjacent convex pole portion and concave pole
portion.
2. The miniature heat-dissipating fan device of claim 1, wherein
Rmax is the maximum radius of the outer rim of the permanent magnet
and Rmin is the minimum radius of the permanent magnet; Ri1 is the
smaller radius of the most inner turn of the planar coil of a wave
winding and Ri2 is the smaller radius of the most outer turn of the
planar coil of the wave winding; Ro1 is the larger radius of the
most outer turn of the planar coil of the wave winding and Ro2 is
the larger radius of the most inner turn of the planar coil of the
wave winding, wherein Ro1<=Rmax and Ri1>=Rmin, Ro1-Ri1=Rs=the
area for the wave winding and
Ri2-Ri1=Ro2-Ro1<=0.3*(Rmax-Rmin).
3. The miniature heat-dissipating fan device of claim 1, wherein
the plural blades are disposed centering around the axis of the
shaft in a centrifugal manner while coupling to the at least one
permanent magnet.
4. The miniature heat-dissipating fan device of claim 2, wherein
each of the permanent magnet is shaped like a flat disc.
5. The miniature heat-dissipating fan device of claim 1, wherein
each of the permanent magnet is made of a material containing
ferrite or boron ferric aluminum, while it is integrally formed
with the plural blades.
6. The miniature heat-dissipating fan device of claim 1, wherein
the wave winding of each planar coil is in a wave shape selected
from the group consisting of a square wave, a triangle wave and a
sine wave.
7. The miniature heat-dissipating fan device of claim 1, wherein
the winding of each planar coil can be in series or parallel
manner.
8. The miniature heat-dissipating fan device of claim 1, wherein
the miniature heat-dissipating fan device has two permanent magnets
arranged therein while the plural blades are sandwiched between the
two permanent magnets.
9. The miniature heat-dissipating fan device of claim 8, wherein
there are two planar coils to be received inside the frame at
positions respectively corresponding to the outer sides of the two
permanent magnets opposite to those facing the blades.
10. The miniature heat-dissipating fan device of claim 1, wherein
each planar coil is formed on an object selected from a flexible
multilayer printed circuit board and a rigid printed circuit
board.
11. The miniature heat-dissipating fan device of claim 10, wherein
each planar coil is integrated with a Hall-effect sensor.
12. The miniature heat-dissipating fan device of claim 1, wherein
each planar coil is structured with at least a hollowed area, each
having a Hall-effect sensor embedded therein.
13. The miniature heat-dissipating fan device of claim 12, wherein
each hollow area is arranged at a position between two neighboring
wave crests of each wave-winding planar coil.
14. The miniature heat-dissipating fan device of claim 12, wherein
each hollow area is structured to channel through the planar coil
from edge to edge.
15. The miniature heat-dissipating fan device of claim 12, wherein
the thickness of the Hall-effect sensor is no larger than that of
the planar coil.
16. The miniature heat-dissipating fan device of claim 1, wherein
the frame is comprised of a sleeve and a base in a manner that an
accommodating space is formed by the enclosure of the sleeve and
the base so as to be used for receiving the shaft, the at least one
planar coil, the at least one permanent magnet, the plural blades
and the magnetically permeable back iron.
17. The miniature heat-dissipating fan device of claim 16, wherein
the sleeve is a cylinder having a plurality of radial-type outlets
formed thereon.
18. The miniature heat-dissipating fan device of claim 16, wherein
the sleeve is a cylinder having at least an axial-type outlet
formed thereon.
Description
[0001] This nonprovisional patent application is a
continuation-in-part of U.S. nonprovisional patent application Ser.
No. 11/834,162 filed Aug. 6, 2007.
TECHNICAL FIELD
[0002] The disclosure relates to a miniature heat-dissipating fan
device, and more particularly, to a miniature heat-dissipating fan
device not only being structured with a magnetically permeable back
iron that is specifically shaped for matching with its planar coil,
but also having its centrifugal blades to be integrally formed with
its permanent magnet.
BACKGROUND
[0003] As the design of modern portable electronic device, e.g.
notebook computer, third-generation cellular phone and personal
digital assistant (PDA), is moving toward lighter, thinner and
smaller while being integrated more powerful central processing
unit (CPU), heat dissipation is becoming an urgent problem that
required to be solved since an electronic device with poor heat
dissipating efficiency may cause the whole system to become
unstable, which is especially true for those future low-voltage
high-current CPUs. Conventionally, the aforesaid heat dissipating
problem is solved by arranging additional heat dissipating modules,
such as those composed of fans, heat pipes and heat-dissipating
fins, in the system. Thereby, heat generated by the operation of
such portable electronic device is transmitted to the
heat-dissipating fins through the heat pipe and then being
dissipated into atmosphere while the operating of the fan is used
for encouraging thermal convection and thus improving heat transfer
efficiency.
[0004] Conventional heat dissipating fans mostly have their fan
blades to be disposed around a sandwich type spindle motor and thus
to be driven to rotate thereby, while the spindle motor is
structured with a solenoid coil in a winding manner matching with
the motor's multi-layered claw pole structure for generating a
multipolar magnetic field. It is known that the magnetically
permeable structure of the spindle motor must at least be comprised
of three layers of claw pole structures and two layers of such
winding coils so as to operate smoothly, and when it is integrated
with a magnetically permeable back iron, such heat dissipating fans
can be too bulky to be used in the modern slim-type electronic
devices.
[0005] In some conventional heat-dissipating fans, the motors used
thereby adopts micro planar coils. However, such motors are
disadvantageous in that the resulting motor will have less amount
of windings in its coil and thus the pole number is less; the
manufacturing cost of such coil is comparatively higher; no
magnetically permeable back iron capable of matching to such coil;
and the motor will generate insufficient torque while it is used
for driving a high-speed centrifugal impeller structure.
[0006] Therefore, it is required to have a highly efficient heat
dissipating module, capable of being fitting inside the limited
space of any modern slim-type electronic device for keeping such
electronic device to operate at a stable temperature.
SUMMARY
[0007] An embodiment of the disclosure is to provide a miniature
heat-dissipating fan device not only being structured with a
magnetically permeable back iron that is specifically shaped for
matching with its planar coil, but also having its centrifugal
blades to be integrally formed with its permanent magnet.
[0008] An embodiment of the disclosure further provides a miniature
heat-dissipating fan device, which comprises: a frame; a shaft,
pivotally connected to the frame; at least a planar coil, each
being received in the frame and formed in a wave winding manner; at
least a permanent magnet, each being connected to the shaft while
being positioned about parallel to the at least one planar coil for
enabling the generation of an alternating multipolar magnetic
field; a plurality of blades, being disposed in a manner that each
is coupled to the at least one permanent magnet so as to rotate
with the at least one permanent magnet synchronously; and at least
a magnetically permeable back iron, each being disposed at a side
of the at least one planar coil and each being structured with a
geometrical shape matching to the wave winding planar coil.
[0009] In an exemplary embodiment of the disclosure, the plural
blades are disposed centering around the axis of the shaft in a
centrifugal manner while coupling to the at least one permanent
magnet.
[0010] In an exemplary embodiment of the disclosure, each of the
permanent magnet is shaped like a flat disc.
[0011] In an exemplary embodiment of the disclosure, each of the
permanent magnet is made of a material containing ferrite or boron
ferric aluminum, while it is integrally formed with the plural
blades.
[0012] In an exemplary embodiment of the disclosure, the wave
winding of each planar coil is in a wave shape selected from the
group consisting of a square wave, a triangle wave and a sine
wave.
[0013] In an exemplary embodiment of the disclosure, the miniature
heat-dissipating fan device has two permanent magnets arranged
therein while the plural blades are sandwiched between the two
permanent magnets.
[0014] In an exemplary embodiment of the disclosure, there are two
planar coils to be received inside the frame at positions
respectively corresponding to the outer sides of the two permanent
magnets opposite to those facing the blades.
[0015] In an exemplary embodiment of the disclosure, each planar
coil is formed on an object selected from a flexible multilayer
printed circuit board and a rigid printed circuit board.
[0016] In an exemplary embodiment of the disclosure, each planar
coil is integrated with a Hall-effect sensor.
[0017] In an exemplary embodiment of the disclosure, each planar
coil is structured with at least a hollowed area, each having a
Hall-effect sensor embedded therein.
[0018] In an exemplary embodiment of the disclosure, each hollow
area is arranged at a position between two neighboring wave crests
of each wave-winding planar coil.
[0019] In an exemplary embodiment of the disclosure, each hollow
area is structured to channel through the planar coil from edge to
edge.
[0020] In an exemplary embodiment of the disclosure, the thickness
of the Hall-effect sensor is no larger than that of the planar
coil.
[0021] In an exemplary embodiment of the disclosure, the frame is
comprised of a sleeve and a base in a manner that an accommodating
space is formed by the enclosure of the sleeve and the base so as
to be used for receiving the shaft, the at least one planar coil,
the at least one permanent magnet, the plural blades and the
magnetically permeable back iron.
[0022] In an exemplary embodiment of the disclosure, the sleeve is
a cylinder having a plurality of radial-type outlets and at least
an axial-type outlet.
[0023] Further scope of applicability of the present application
will become more apparent from the detailed description given
hereinafter. However, it should be understood that the detailed
description and specific examples, while indicating preferred
embodiments of the invention, are given by way of illustration
only, since various changes and modifications within the spirit and
scope of the invention will become apparent to those skilled in the
art from this detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] The embodiment of the disclosure will become more fully
understood from the detailed description given herein below and the
accompanying drawings which are given by way of illustration only,
and thus are not limitative of the disclosure and wherein:
[0025] FIG. 1 is an exploded view of a miniature heat-dissipating
fan device according to an exemplary embodiment of the
invention.
[0026] FIG. 2 is a cross sectional view of a miniature
heat-dissipating fan device according to an exemplary embodiment of
the invention.
[0027] FIG. 3 is a top view showing an integrated structure of two
permanent magnets and centrifugal blades according to an exemplary
embodiment of the invention.
[0028] FIG. 4 is an A-A sectional view of FIG. 3.
[0029] FIG. 5A is a schematic diagram depicting a magnetically
permeable back iron is in a geometrical shape matching to a planar
coil according to the disclosure.
[0030] FIG. 5B is a schematic diagram depicting a planar coil
according to the disclosure.
[0031] FIG. 5C is a schematic diagram depicting the winding of the
coil in a series manner.
[0032] FIG. 5D is a schematic diagram depicting the winding of the
coil in a parallel manner.
[0033] FIG. 6 is a top view showing an integrated structure of a
single permanent magnet and centrifugal blades according to another
exemplary embodiment of the invention.
[0034] FIG. 7 is a B-B sectional view of FIG. 6.
[0035] FIG. 8 shows a Hall-effect sensor being fitted in a planar
coil of the invention.
[0036] FIG. 9 is a cross sectional diagram showing a planar coil
having a Hall-effect sensor embedded therein according to an
exemplary embodiment of the invention.
[0037] FIG. 10 shows a miniature heat-dissipating fan device
according to another exemplary embodiment of the invention.
DESCRIPTION OF THE EXEMPLARY EMBODIMENTS
[0038] For your esteemed members of reviewing committee to further
understand and recognize the fulfilled functions and structural
characteristics of the invention, several exemplary embodiments
cooperating with detailed description are presented as the
follows.
[0039] Please refer to FIG. 1 and FIG. 2, which show a miniature
heat-dissipating fan device according to an exemplary embodiment of
the invention. The miniature heat-dissipating fan device 10 is
substantially a frame composed of a cylinder-like sleeve 11 and a
disc-like base 12. As shown in FIG. 1, a shaft 13 is arranged in
the frame in a manner that one axial end of the shaft 13 is
pivotally connected to base 12 by a bearing 14. In an exemplary
embodiment of the invention, the bearing 14 can be a micro-ball
bearing, a journal bearing or a magnetic-suspension bearing. The
journal bearing could be the self-lubricant type.
[0040] One characteristic of the miniature heat-dissipating fan
device of the invention is that there are two permanent magnets 16,
each shaped like a flat disc, to be disposed at positions
neighboring to the center of the shaft 13, while each has a
plurality of magnetic regions of alternating north and south
polarities, referring as the north pole regions 161 and the south
pole regions 162, and a plurality of blades 17 are sandwiched
between the two permanent magnets 16. Each of the permanent magnet
16 is made of a material containing ferrite or boron ferric
aluminum, while it is integrally formed with the plural blades 17.
As shown in FIG. 2 to FIG. 4, the plural blades 17 are disposed
centering around the axis of the shaft 13 in a centrifugal manner;
and an inlet 111 and a plurality of radial-type outlets 112 are
formed on the sleeve 11 in a manner that the inlet 111 aligned with
the axis of the shaft 13 while the plural outlets are positioned
corresponding to the plural blades 14 so that the hot air generated
from an external electronic device can be sucked into the fan
device 10 through the inlet 111 and then to be exhausted from the
outlets 112 by the rotation of the blades 17.
[0041] Moreover, there are two planar coils 18 to be received
inside the frame at positions respectively corresponding to the
outer sides of the two permanent magnets 16 opposite to those
facing the blades 17 while enabling the two permanent magnets 16 to
be positioned about parallel to the two planar coil 18. Each planar
coil 18 can be formed on an object selected from a flexible
multilayer printed circuit board and a rigid printed circuit board,
while the winding 181 of each planar coils 18 is formed by a wave
winding means, which can be formed in a shape selected from the
group consisting of a square wave, a triangle wave and a sine wave.
As shown in FIG. 5, the wave winding 181 is in a shape of a square
wave. As there is a printed circuit board (PCB) 15 disposed on the
base 12 which is electrically connected to the planar coils 18, an
alternating multipolar magnetic filed can be induced by the planar
coils 18 as seen as power of a two-phase direct current power
source is fed to the planar coils 18 though the PCB 15 and
controlled thereby, so that the alternating multipolar magnetic
filed will affect the alternating north pole regions 161 and the
south pole region 162 of each permanent magnet 18 in a manner that
the two permanent magnets 18 are pushed to rotate for bringing the
shaft 13 to rotate synchronously with the two permanent magnets 18
and thus bringing the plural blades 17 to rotate as well.
[0042] As the induction of the alternating multipolar magnetic
filed by the feeding of power of a two-phase direct current power
source is fed to the planar coils 18 though the control of the PCB
15 is disclosed in TW Pat. Appl. No. 94204332, it is provided and
known to those skilled in the art so that it is not described
further herein.
[0043] Another characteristic of the miniature heat-dissipating fan
device of the invention is that there are magnetically permeable
back irons 19 to be positioned respectively at positions
corresponding to the outer sides of each planar coil 18, while each
being structured with a geometrical shape matching to the wave
winding 181 of the planar coil 18, as shown in FIG. 5A, for
concentrating the flow of magnetic lines to pass thorough the
magnetically permeable back iron 19 so as to increase the effective
magnetic flux density.
[0044] Further detail illustration of planar coil 18 can be seen in
FIG. 5B. The planar coil 18 basically comprises at least one layer
of coil being wound on a same level, and on such level, said layer
is formed by a plurality of turns of coil. The plurality of turns
of coil is formed by continuous wire wound symmetrically around the
radial center 182 of the planar coil 18. Each turn of coil has a
plurality of convex pole portion 183 and corresponding concave pole
portion 184. The convex pole portion 183 and the corresponding
concave pole portion 184 consists of a arc section 185 and two line
sections 186 and 187. The center of the arc section 185 is the
radial center 182 which is also the center the two line sections
186 and 187 radially pointing to virtually. And each line section
is common-owned by the adjacent convex pole portion and concave
pole portion.
[0045] As shown in FIG. 5B, Rmax is the maximum radius of the outer
rim of the permanent magnet and Rmin is the minimum radius of the
permanent magnet; Ri1 is the smaller radius of the most inner turn
of the same level coil of a wave winding and Ri2 is the smaller
radius of the most outer turn of the same level coil of a wave
winding; Ro1 is the larger radius of the most outer turn of the
same level coil of a wave winding and Ro2 is the larger radius of
the most inner turn of the same level coil of a wave winding;
wherein Ro1<=Rmax and Ri1>=Rmin, Ro1-Ri1=Rs=the area for the
wave winding and Ri2-Ri1=Ro2-Ro1<=0.3*(Rmax-Rmin)
[0046] In addition, in this disclosure, the winding of coil on the
single level can be in series or in parallel, which is shown in
FIGS. 5C and 5D respectively. And in a structure of multiple levels
of coil according to present disclosure, each coil on different
levels can be connected electrically in series or parallel
manner.
[0047] In another exemplary embodiment of the invention, the
miniature heat-dissipating fan device can be structured with a
single permanent magnet 16 and centrifugal blades 17, as that shown
in FIG. 6 and FIG. 7. As there is one permanent magnet 16 less than
the aforementioned embodiment and thus only one planar coil and one
magnetically permeable back iron 19 is required, the overall
thickness of the resulting miniature heat-dissipating fan device is
greatly reduced.
[0048] It is emphasized that the frame formed by the sleeve 11 and
the base is used for receiving and securing the stator structure
composed of the planar coils 18 and the magnetically permeable back
iron 19, but the mechanism for receiving and securing such stator
structure is not limited thereby. That is, other mechanisms capable
of receiving and securing such stator structure can be adopted by
the miniature heat-dissipating fan device of the invention and used
as the frame. For instance, the frame can be replaced by a simple
strut structure. Similarly, although the aforesaid inlet and
outlets formed on the sleeve 11 are all indispensable components
for the miniature heat-dissipating fan device, their shapes and
positions can be varied with respect to actual requirement or the
formation of the frame.
[0049] For brushless DC motor, Hall-effect sensor is usually being
used for detecting magnet field variations and thus issuing a motor
control signal so as to ensure the motor to operate stably. Please
refer to FIG. 8 and FIG. 9, which show a Hall-effect sensor being
fitted in a planar coil of the invention. As shown, the planar coil
18 is structured with a hollow area 183 to be used for receiving a
Hall-effect sensor 20. In this exemplary embodiment, the hollow
area 182 is formed at a position between two neighboring wave
crests 181a, 181b of each wave-winding 181 of the planar coil 18.
Moreover, the hollow area 182 is structured to channel through the
planar coil 18 from edge to edge. It is noted that a Hall-effect
sensor 20 of 0.55 mm thickness is adopted when the thickness of the
planar coil 18 is about 0.6 mm so that the Hall-effect sensor 20
cab be embedded deeply into the planar coil 18, as shown in FIG. 9,
by which, not only the disposition of the Hall-effect sensor 20
will not take up additional space, but also the overall thickness
of the whole structure can be reduced. In addition, while coil is
printing on a rigid or flexible multi-layered board, the process
for embedding Hall-effect sensor can be incorporated with the
printing of the coil, thereby, the overall manufacturing process
can be simplified.
[0050] Please refer to FIG. 10, which shows a miniature
heat-dissipating fan device according to another exemplary
embodiment of the invention. In appearance, only a sleeve 11a, a
base 12 and a circuit 15 can be seen. However, the miniature
heat-dissipating fan device of FIG. 10 is also structured with a
shaft 13, a bearing 14, a permanent magnet 16, centrifugal blades
17, planar coils 18 and a magnetically permeable back iron 18,
which are similar to that illustrated in FIG. 1 and thus are not
described further herein. The characteristic of the present
embodiment shown in FIG. 10 is that: considering the relationship
between amount of wind and the flow channel disposition, an
axial-type outlet 112a is formed on the sleeve 11a, by which hot
air generated by the centrifugal blades 17 can be concentrated and
exhausted out of the outlet 112. With respect to the size of the
outlet 112a as well as the location for disposing the same, they
are dependent only upon the actual size of the miniature
heat-dissipating fan device and thus are not limited by the
embodiment shown in FIG. 10.
[0051] To sum up, as the miniature heat-dissipating fan device 10
of the invention, as that shown in FIG. 2, is designed with an
integrated structure of permanent magnets 16 and centrifugal blades
17, not only its manufacturing process can be simplified while
lowering the manufacturing cost, but also the overall thickness of
the fan device is greatly reduce so as to be used in those
slim-type electronic devices. In addition, as the plural blades 17
is arranged in a centrifugal manner that the axial-inflowing air
flow, being sucked therein through the inlet 111, can be exhausted
out of the fan device radially through the plural outlets 112, by
which convection is enforced, but with enhanced efficiency.
Moreover, by designing each magnetically permeable back iron 19
with a geometrical shape matching to the wave winding 181 of the
planar coil 18, the effective magnetic flux density is
increased.
[0052] The embodiment of the disclosure being thus described, it
will be obvious that the same may be varied in many ways. Such
variations are not to be regarded as a departure from the spirit
and scope of the invention, and all such modifications as would be
obvious to one skilled in the art are intended to be included
within the scope of the following claims.
* * * * *