U.S. patent application number 11/211802 was filed with the patent office on 2006-02-02 for electronic component cooling apparatus.
This patent application is currently assigned to SANYO DENKI CO., LTD.. Invention is credited to Masayuki Iijima, Masashi Miyazawa, Kouji Ueno.
Application Number | 20060023425 11/211802 |
Document ID | / |
Family ID | 32985520 |
Filed Date | 2006-02-02 |
United States Patent
Application |
20060023425 |
Kind Code |
A1 |
Iijima; Masayuki ; et
al. |
February 2, 2006 |
Electronic component cooling apparatus
Abstract
An electronic component cooling apparatus comprises a so-called
water-cooled heat sink, a radiator to be cooled by a motor-driven
fan, first and second coolant paths for circulating a coolant
between the heat sink and the radiator, and a motor-driven pump for
giving a moving energy to the coolant. A plurality of engaging
pieces of the motor-driven fan and a plurality of engaged portion
of the radiator are engaged to connect the motor-driven fan and the
radiator.
Inventors: |
Iijima; Masayuki; (Nagano,
JP) ; Miyazawa; Masashi; (Nagano, JP) ; Ueno;
Kouji; (Nagano, JP) |
Correspondence
Address: |
RANKIN, HILL, PORTER & CLARK LLP
4080 ERIE STREET
WILLOUGHBY
OH
44094-7836
US
|
Assignee: |
SANYO DENKI CO., LTD.
Tokyo
JP
|
Family ID: |
32985520 |
Appl. No.: |
11/211802 |
Filed: |
August 25, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10813328 |
Mar 30, 2004 |
|
|
|
11211802 |
Aug 25, 2005 |
|
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Current U.S.
Class: |
361/699 ;
257/E23.098 |
Current CPC
Class: |
H01L 23/473 20130101;
F04D 13/0673 20130101; H01L 2924/0002 20130101; H01L 2924/0002
20130101; F04D 13/0633 20130101; F28D 1/05366 20130101; F04D 29/588
20130101; H01L 2924/00 20130101; F28D 2021/0031 20130101 |
Class at
Publication: |
361/699 |
International
Class: |
H05K 7/20 20060101
H05K007/20 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 31, 2003 |
JP |
2003-097393 |
Claims
1. A motor-driven pump used in an electronic component cooling
apparatus, comprising: a rotor having a rotating body, a plurality
of rotary side magnetic poles and a shaft, the rotating body having
a cylindrical peripheral wall portion and a closing wall portion
integrally formed with the peripheral wall portion to close one end
of an inner space enclosed by the peripheral wall portion, the
rotary side magnetic poles being formed from permanent magnets and
arranged on an inner peripheral surface of the peripheral wall
portion, the shaft being fixed at one end thereof to a center of
the closing wall portion and extending through a center of the
peripheral wall portion; a bearing rotatably supporting the shaft;
a cylindrical bearing holder in which the bearing is fitted and
held; a stator having a stator core mounted on an outer periphery
of the bearing holder and arranged inside the rotating body and a
plurality of excitation coils wound around the stator core; an
exciting current supply circuit for supplying an exciting current
to the plurality of excitation coils; a waterproof structure
including a seal member for watertightly closing one of open ends
of the bearing holder which does not face the closing wall portion
of the rotating body, the waterproof structure being adapted to
waterproof the stator and the exciting current supply circuit; an
impeller having a blade mounting portion arranged on at least the
closing wall portion of the rotating body and a plurality of blades
provided at the blade mounting portion; and a housing having a
liquid inlet and a liquid outlet and accommodating therein elements
such as the rotor, the impeller and the stator, wherein when the
rotor, the impeller and the bearing are submerged in the coolant
and the impeller is rotated, the housing draws in the liquid
coolant through the liquid inlet and discharges it from the liquid
outlet.
2. The motor-driven pump as defined in claim 1, wherein the closing
wall portion of the rotating body is formed with one or more
through-holes extending therethrough in a thickness direction
thereof to allow the coolant to flow through the closing wall
portion.
3. The motor-driven pump as defined in claim 2, wherein the blade
mounting portion of the impeller has a portion that faces almost
entirely the closing wall portion of the rotating body, and the
portion is formed with one or more through-holes aligned with the
one or more through-holes.
4. The motor-driven pump as defined in claim 1, wherein the blade
mounting portion of the impeller has a cylindrical extended
mounting portion extending along the peripheral wall portion of the
rotating body, and the plurality of blades are each shaped to
extend continuously from over the blade mounting portion to over
the cylindrical extended mounting portion.
5. A motor-driven pump usable in an electronic component cooling
apparatus, comprising: a rotor having a rotating body, a plurality
of rotary side magnetic poles and a shaft, the rotating body having
a cylindrical peripheral wall portion and a closing wall portion
integrally formed with the peripheral wall portion to close one end
of an inner space enclosed by the peripheral wall portion, the
rotary side magnetic poles being formed from permanent magnets and
arranged on an inner peripheral surface of the peripheral wall
portion, the shaft being fixed at one end thereof to a center of
the closing wall portion and extending through a center of the
peripheral wall portion; two bearings spaced from each other in an
axial direction of the shaft to rotatably support the shaft; a
cylindrical bearing holder in which the two bearings are fitted and
held; a retainer mechanism arranged between the other end of the
shaft and one of the two bearings which is situated on an opposite
side to the closing wall portion and adapted to prevent the shaft
from coming off; a stator having a stator core mounted on an outer
periphery of the bearing holder and arranged inside the rotating
body and a plurality of excitation coils wound around the stator
core; an exciting current supply circuit for supplying an exciting
current to the plurality of excitation coils; a waterproof
structure including a seal member for watertightly closing one of
open ends of the bearing holder which does not face the closing
wall portion of the rotating body, the waterproof structure being
adapted to waterproof the stator and the exciting current supply
circuit; an impeller having a blade mounting portion arranged on at
least the closing wall portion of the rotating body and a plurality
of blades provided at the blade mounting portion; and a housing
having a liquid inlet and a liquid outlet and accommodating therein
elements such as the rotor, the impeller and the stator, wherein
when the rotor, the impeller and the two bearings are submerged in
the coolant and the impeller is rotated, the housing draws in the
liquid coolant through the liquid inlet and discharges it from the
liquid outlet.
6. The motor-driven pump as defined in claim 5, wherein at least
one liquid path extending along the shaft is formed between an
inner peripheral surface of the bearing holder and an outer
peripheral surface of each of the two bearings.
7. The motor-driven pump as defined in claim 6, wherein at least
one groove extending along the shaft is formed in that portion of
the inner peripheral surface of the bearing holder which faces the
outer peripheral surface of the bearings, and the groove
constitutes the liquid path.
8. The motor-driven pump as defined in claim 7, wherein a plurality
of the grooves are formed at equal intervals in a peripheral
direction.
9. The motor-driven pump as defined in claim 7, wherein the inner
peripheral surface of the bearing holder is formed with one or more
narrow elongate grooves that extend along the shaft and face the
outer peripheral surfaces of the two bearings, respectively, and
the one or more narrow elongate grooves constitute the liquid
path.
10. The motor-driven pump as defined in claim 6, wherein the
bearings are ball bearings.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to an electronic component
cooling apparatus for forcibly cooling electronic components such
as microcomputers and to a motor-driven pump and a radiator used in
the electronic component cooling apparatus.
[0002] Most of conventional electronic component cooling
apparatuses, as disclosed in U.S. Pat. No. 5,519,574, have a
combination of a heat sink having a plurality of radiation fins on
a surface of a base plate and a motor-driven fan for forcibly
cooling these fins and the surface of the base plate.
[0003] As an amount of heat generated by electronic components
increases, however, a problem arises that simply air-cooling the
heat sink cannot cool the electronic components down to a
sufficient degree.
SUMMARY OF THE INVENTION
[0004] The prevent invention has been made to solve the problems
described above. Accordingly, an object of the present invention is
to provide an electronic component cooling apparatus that can cool
electronic components generating a large amount of heat down to a
sufficient level by means of so-called water-cooling.
[0005] Another object of the present invention is to provide a
small water-cooling type electronic component cooling
apparatus.
[0006] Still another object of the present invention is to provide
an electronic component cooling apparatus that allows a
motor-driven fan to be easily mounted at a radiator.
[0007] Yet another object of the present invention is to provide an
electronic component cooling apparatus in which noise produced by
the motor-driven fan mounted on the radiator is small.
[0008] A further object of the present invention is to provide an
electronic component cooling apparatus having a motor-driven fan
with a high air-blowing performance.
[0009] A still further object of the present invention is to
provide an electronic component cooling apparatus having a
water-cooling type heat sink with a higher heat dissipation
factor.
[0010] A yet further object of the present invention is to provide
a motor-driven pump suited for use in the electronic component
cooling apparatus.
[0011] It is a further object of the present invention to provide a
motor-driven pump which is smaller than conventional pumps and
capable of suppressing a temperature rise in a bearing and which
does not require resupply of a lubricant to the bearing.
[0012] It is a still further object of the present invention to
provide a motor-driven pump capable of supplying a coolant into a
bearing holder reliably and smoothly.
[0013] It is a still further object of the present invention to
provide a motor-driven pump capable of supplying the coolant
reliably into a rotating body.
[0014] It is a still further object of the present invention to
provide a motor-driven pump with an improved pump performance
without increasing a dimension in an axial direction.
[0015] It is a still further object of the present invention to
provide a motor-driven pump capable of using ball bearings as the
bearings therefor.
[0016] It is a still further object of the present invention to
provide a motor-driven pump which is small in size and has a high
cooling performance.
[0017] It is a yet further object of the present invention to
provide a radiator suited for use in the electronic component
cooling apparatus.
[0018] It is a yet further object of the present invention to
provide a radiator which is small in size and has a high heat
exchange efficiency.
[0019] It is a yet further object of the present invention to
provide a radiator which can prevent a degradation of the cooling
performance caused by bubbles getting into a coolant.
[0020] An electronic component cooling apparatus of the present
invention has a so-called water-cooled heat sink, a radiator cooled
by a motor-driven fan, first and second coolant paths for
circulating a coolant between the heat sink and the radiator, and a
motor-driven pump for giving a moving energy to the coolant.
[0021] The heat sink has an electronic component mounting surface
on which electronic components to be cooled, such as a CPU, are
mounted and a coolant path which has a coolant inlet and a coolant
outlet and through which a liquid as a coolant for forcibly cooling
the electronic component mounting surface flows. The radiator has a
liquid path with a coolant inlet and a coolant outlet, through
which a coolant flows and which is air-cooled to cool the coolant.
The motor-driven fan is mounted on a heat dissipating portion of
the radiator to supply cooling air to the radiator. A first coolant
path constructed of, for example, piping connects the coolant
outlet of the heat sink to the coolant inlet of the radiator, and a
second coolant path joins the coolant outlet of the radiator to the
coolant inlet of the heat sink. The motor-driven pump is installed
in the first coolant path or the second coolant path to give a
moving energy to the coolant.
[0022] In this construction, even when a large amount of heat is
generated from the electronic components, the heat sink can be
positively cooled with the coolant, thus enhancing the cooling
performance much better than when the heat sink is cooled only by
air.
[0023] The motor-driven fan includes: an air channel body having a
suction port at one end thereof facing a front of the heat
dissipating portion of the radiator and a discharge port at the
other end thereof; an impeller having a plurality of blades, at
least a part of the impeller being arranged inside the air channel
body; a motor for rotating the impeller to draw in air through the
suction port and discharge air from the discharge port; and a
plurality of engaging pieces integrally provided to the air channel
body. In this case the radiator is provided with a plurality of
engaged portions with which the plurality of the engaging pieces
engage. It is theoretically possible to cool the radiator by
blowing air against the heat dissipating portion of the radiator.
However, the heat dissipating portion of the radiator is complex in
shape and has a large resistance against the air being blown.
Hence, it is required for enhancing the cooling efficiency to
increase the revolution speed of the motor-driven fan, which in
turn generates more noise. On the other hand, a construction in
which the motor-driven fan draws in air through the heat
dissipating portion of the radiator can discharge heated air from
the heat dissipating portion without increasing the rotation speed
of the motor-driven fan more than necessary even when the
construction of the heat dissipating portion of the radiator is
complex. This construction can also reduce noise. Further, if a
construction is employed in which the motor-driven fan is mounted
at the radiator by engaging the engaging pieces into the engaged
portions, the mounting of the motor-driven fan onto the radiator is
simplified, thereby enhancing the assembly work efficiency.
[0024] Further, if the edges of a plurality of blades facing the
front of the heat dissipating portion are sloping gradually away
from the dissipating portion as each of the edges extends in a
radially outward direction from the rotating center of the
impeller, noise can be reduced. Further, if a plurality of webs
connecting the housing of the motor and the end portion of the air
channel body on the side of the discharge port are situated outside
the discharge port, or the end portion on the side of the discharge
port is arranged lower than the uppermost surface of the housing of
the motor, the air discharge performance can be increased and the
load noise can be decreased, compared to when the webs are arranged
inside the end portion of the discharge port side of the air
channel body.
[0025] The heat sink includes: a base plate having the electronic
component mounting surface and a heat dissipating surface which is
opposite to the electronic component mounting surface in a
thickness direction of the base plate and in direct contact with
the coolant; a top plate facing the base plate with a predetermined
space therebetween; and a peripheral wall portion joining the base
plate and the top plate. This heat sink is preferably provided with
a coolant inlet and a coolant outlet so that the coolant can flow
from one side of the heat dissipating surface to the other side of
the heat dissipating surface facing the one side. It is also
preferred that the base plate be so shaped in a transverse cross
section as to form a resistance increasing portion between the one
side and the other side of the heat dissipating surface to increase
a resistance against a flow of the coolant. This arrangement causes
the coolant that has entered from the coolant inlet into the heat
sink to be accelerated in velocity at the resistance increasing
portion before being discharged from the coolant outlet. As a
result, the heat exchange efficiency can be increased at the
resistance increasing portion, which in turn enhances the overall
heat exchange efficiency of the heat sink.
[0026] A plurality of radiation fins may be integrally provided on
the heat dissipating surface of the base plate of the heat sink to
enhance the heat exchange efficiency. In that case, the radiation
fins preferably extend in a first direction from one side where the
coolant inlet is situated toward the other side where the coolant
outlet is situated. It is also preferred that the radiation fins be
arranged along the heat dissipating surface at predetermined
intervals in a second direction perpendicular to the first
direction. With the radiation fins arranged in this manner, an
efficient heat exchange can be realized by the coolant flowing
through passages continuously formed between two adjacent radiation
fins. In this case, it is preferred that the coolant inlet and the
coolant outlet pierce through the top plate in a thickness
direction thereof at positions near the one side and the other
side, respectively. With this arrangement, the coolant that has
entered from the coolant inlet flows against the heat dissipating
surface and diffuses, without extreme imbalance, into a space
between the top plate and the base plate. The diffused coolant
gathers again toward the coolant outlet and goes out therefrom
without imbalance. As a result, the entire heat sink is cooled. In
this case, it is preferred that the positions of both ends of the
radiation fins in the first direction be determined so that the
speed of the coolant does not vary excessively greatly among flow
passages as the coolant flows in through the coolant inlet and
flows out from the coolant outlet through the flow passages each
formed between two adjacent radiation fins.
[0027] The electronic component cooling apparatus of the present
invention may use a variety of motor-driven pumps. The inventor of
this invention invented a small motor-driven pump suited for use
with the electronic component cooling apparatus. The small
motor-driven pump comprises: a rotor having a rotating body, a
plurality of rotary side magnetic poles and a shaft. The rotating
body has a cylindrical peripheral wall portion and a closing wall
portion integrally formed with the peripheral wall portion to close
one end of an inner space enclosed by the peripheral wall portion.
The rotary side magnetic poles are formed with permanent magnets
and arranged on an inner peripheral surface of the peripheral wall
portion. The shaft is fixed at one end thereof to a center of the
closing wall portion and extends through a center of the peripheral
wall portion. The motor-driven pump also comprises bearings for
rotatably supporting the shaft; a cylindrical bearing holder in
which the bearings are fitted and held; a retainer mechanism
arranged between the other end of the shaft and one of the two
bearings which is situated far side from the closing wall portion
and adapted to prevent the shaft from coming off; a stator having a
stator core mounted on an outer periphery of the bearing holder and
arranged inside the rotating body and a plurality of excitation
coils wound around the stator core; an exciting current supply
circuit for supplying an exciting current to the plurality of
excitation coils; and a waterproof structure including a seal
member for watertightly closing one of open ends of the bearing
holder which does not face the closing wall portion of the rotating
body. The waterproof structure is adapted to waterproof the stator
and the exciting current supply circuit. The motor-driven pump also
comprises an impeller having a blade mounting portion arranged on
at least the closing wall portion of the rotating body and a
plurality of blades provided at the blade mounting portion; and a
housing having a liquid inlet and a liquid outlet and accommodating
therein elements such as the rotor, the impeller and the stator.
When the rotor, the impeller and the bearings are submerged in the
coolant and the impeller is rotated, the housing draws in the
liquid coolant from the liquid inlet and discharges it from the
liquid outlet.
[0028] In the construction of this motor-driven pump, the stator
core is situated on the outer periphery of the bearing holder, with
the rotor turning outside the stator core. This construction can
reduce the axial dimension of the motor-driven pump and also
enhance the pump performance by taking full advantage of the
inertia of the rotor. Further, in this construction, since the
liquid enters into the interior of the bearing holder, heat from
the stator can also be released through the bearing holder to the
liquid flowing through the interior of the pump. Further, because
the liquid entering into the bearing holder serves as a lubricant
for the bearings, there is no need to replenish the lubricant to
the bearings, significantly extending the life of the motor-driven
pump. Another advantage of this construction is that since it
eliminates the need for supplying a lubricant to the bearings, ball
bearings can be used as the bearings.
[0029] While a single bearing may be used, two bearings are
preferably used to ensure a stable support of the shaft. In this
case, it is preferred that at least one liquid path extending along
the shaft be formed between the inner peripheral surface of the
bearing holder and the outer peripheral surface of the two
bearings. This liquid path allows a whole interior of the bearing
holder, including a space formed between the two bearings in the
bearing holder, to be completely filled with the flowing liquid.
This liquid path can be formed by forming at least one groove
extending along the shaft in at least the inner peripheral surface
of the bearing holder or the outer peripheral surface of the
bearings. At least one groove extending along the shaft should
preferably be formed in that part of the inner peripheral surface
of the bearing holder which faces the outer peripheral surface of
the bearings rather than to be formed in the outer peripheral
surface of the bearings, and then ready made bearings can be used.
When a plurality of grooves are to be formed, they are preferably
formed at equal intervals in the peripheral direction. This
arrangement can eliminate a possibility that the presence of the
plurality of grooves may put the center of the bearings out of
alignment with the center of the bearing holder. Further, the inner
peripheral surface of the bearing holder may be formed with one or
more narrow elongate grooves that extend along the shaft and face
the outer peripheral surfaces of both of the two bearings. The one
or more narrow elongate grooves may be used as the liquid path.
This arrangement makes it easy to form the grooves which face both
of the bearings.
[0030] Further, the closing wall portion of the rotating body may
be formed with one or more through-holes piercing therethrough in a
thickness direction thereof to allow the coolant to flow through
the closing wall portion. The through-holes ensure a smooth flow of
the liquid between the interior and the exterior of the rotating
body. When the blade mounting portion of the impeller has a portion
that almost entirely faces the closing wall portion of the rotating
body, it is necessary to form also in this portion one or more
through-holes that are aligned with the one or more through-holes
formed in the closing wall portion.
[0031] The blade mounting portion of the impeller may be provided
with a cylindrical extended mounting portion extending along the
peripheral wall portion of the rotating body. Further, the
plurality of blades may each be shaped to extend continuously from
over the blade mounting portion to over the cylindrical extended
mounting portion. This arrangement can make the most of the outer
surface of the rotating body in forming long blades, thereby
enhancing the performance of the motor-driven pump.
[0032] Further, since no shaft fixing brackets exist in the space
in which the impeller rotates, nothing obstructs the liquid inflow,
improving the pump performance.
[0033] The radiator used in the electronic component cooling
apparatus can have any desired construction as long as it can be
formed as small as possible. The inventor developed a construction
suited for such a radiator. This radiator comprises: a plurality of
liquid passages arranged side by side; radiation fins attached to
outer surfaces of the liquid passages; two liquid tanks arranged
one on each side of the plurality of liquid passages and
communicably connected to both ends of the plurality of liquid
passages; and a liquid inlet and a liquid outlet provided in one
and the other of the two liquid tanks respectively. Furthermore, a
chamber in each of the two liquid tanks is divided, in a direction
of arrangement of the plurality of liquid passages, into m plus one
(m is an integer of one or more) sub-chambers by m partition walls.
Then the sub-chambers in each of the two liquid tanks and the
plurality of liquid passages are connected with each other in such
a manner that one or more of the liquid passages function as liquid
paths winding between the liquid inlet and the liquid outlet. In
this radiator, since the liquid path is constructed of one or more
winding liquid passages, the liquid path can be lengthened and the
heat exchange efficiency enhanced.
[0034] The liquid inlet and the liquid outlet can be provided only
in one of the two liquid tanks. In this construction, the one of
the tank provided with the liquid inlet and outlet therein, in a
direction of arrangement of the plurality of liquid passages, is
divided into n plus one (n is integer of two or more) sub-chambers
by n partition walls, while the other tank, in a direction of
arrangement of the plurality of liquid passages, is divided into n
sub-chambers by n minus one partition walls. In this kind of
radiator, since both of the liquid inlet and the liquid outlet are
provided in one of the liquid tanks, a space for locating a first
coolant path and a second coolant path connected respectively to
the liquid inlet and the liquid outlet can be made smaller.
[0035] The two liquid tanks can be so arranged that the uppermost
sub-chamber in one of the two tanks is situated higher than the
uppermost sub-chamber in the other tank. Also, the uppermost
sub-chamber of the one tank situated higher than the uppermost
sub-chamber of the other tank is formed in such a size and
dimension as to allow a space to be defined therein--that is not
filled with the liquid. In this arrangement, bubbles that may get
into the liquid stay in the space, thereby effectively preventing
degraded cooling efficiency to be caused when the bubbles get into
the liquid.
BRIEF DESCRIPTION OF THE DRAWINGS
[0036] These and other objects and many of the attendant advantages
of the present invention will become better understood by reference
to the following detailed description when considered in connection
with the accompanying drawings.
[0037] FIG. 1 is a plan view showing a configuration of an
embodiment of an electronic component cooling apparatus according
to the present invention.
[0038] FIGS. 2A and 2B are a plan view and a side view of a heat
sink used in the electronic component cooling apparatus of FIG. 1.
FIG. 2C is a cross-sectional view taken along the line IIC-IIC of
FIG. 2A, and FIG. 2D is a plan view of a base plate.
[0039] FIGS. 3A and 3B are a plan view and a front view of a
motor-driven pump used in the electronic component cooling
apparatus of FIG. 1.
[0040] FIG. 4 is a cross-sectional view taken along the line IV-IV
of FIG. 3B.
[0041] FIG. 5 is an enlarged cross sectional view taken along the
line V-V of FIG. 3B.
[0042] FIG. 6A is a cross-sectional view showing another example of
a motor-driven pump used in the present invention. FIG. 6B is a
horizontal cross-sectional view showing the shaft and surroundings
thereof of the motor-driven pump indicated of FIG. 6A.
[0043] FIG. 7 is a cross-sectional view showing still another
example of a motor-driven pump used in the present invention.
[0044] FIGS. 8A to 8D are a plan view, a front view, a left side
view and a bottom view of a radiator used in the electronic
component cooling apparatus of FIG. 1.
[0045] FIG. 9 is a schematic diagram showing a configuration of
liquid paths in a radiator used in the electronic component cooling
apparatus of FIG. 1.
[0046] FIG. 10 is a schematic diagram showing another configuration
of liquid paths in a radiator.
[0047] FIG. 11 is a schematic diagram showing a further
configuration of liquid paths in a radiator.
[0048] FIGS. 12A to 12D are a plan view, a front view, a left side
view and a partly cutaway front view of a motor-driven fan used for
air-cooling a radiator used in the electronic component cooling
apparatus of FIG. 1.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0049] Now, by referring to the accompanying drawings, one
embodiment of an electronic component cooling apparatus according
to the present invention will be described in detail. FIG. 1 is a
plan view showing a construction of embodiment of an electronic
component cooling apparatus 1 according to the present invention.
The electronic component cooling apparatus 1 has a water-cooled
heat sink 3 having a coolant path therein, a radiator 7 cooled by a
motor-driven fan 5, and a motor-driven pump 13 for giving a moving
energy to the coolant in order to circulate the coolant between the
heat sink 3 and the radiator 7.
[0050] The heat sink 3 has an electronic component mounting surface
for mounting electronic components, such as a CPU, to be cooled.
Also the heat sink 3 has a coolant path, with a coolant inlet (a
cylindrical member 35) and a coolant outlet (a cylindrical member
36), through which a liquid coolant flows to forcibly cool the
electronic component mounting surface. The radiator 7 has a liquid
path, with an inlet 80 and an outlet 81, through which the coolant
flows and which is air-cooled by dissipating heat from the coolant.
The motor-driven fan 5 is mounted on a heat dissipating portion of
the radiator 7 to supply cooling air to the radiator 7. The first
coolant path 9 constructed of pipes or others joins the coolant
outlet 36 of the heat sink 3 to the coolant inlet 80 of the
radiator 7, and the second coolant path 11 joins the coolant outlet
81 of the radiator 7 to the coolant inlet 35 of the heat sink
3.
[0051] As shown in FIG. 2, the heat sink 3 comprises a base plate
31 and a top plate case 34 and has a coolant path formed therein.
The base plate 31 is made of a metal with a high heat conductivity,
such as copper and aluminum, and has an electronic component
mounting surface 31a, and a heat dissipating surface 31b which is
in direct contact with the coolant and faces the electronic
component mounting surface 31a in the thickness direction of the
base plate. The top plate case 34 has a top plate 32 facing the
base plate 31 with a predetermined gap therebetween and a
peripheral wall portion 33 connecting the base plate 31 and the top
plate 32. While the top plate case 34 may be formed of a metal with
a high heat conductivity such as copper and aluminum, like a base
plate 31, it can also be integrally formed of a synthetic resin
material. The top plate case 34 is integrally formed with a
cylindrical member 35 constituting the coolant inlet and a
cylindrical member 36 constituting the coolant outlet. It is
preferred that the coolant inlet (the cylindrical member 35) and
the coolant outlet (the cylindrical member 36) be arranged so that
the coolant flows from one side 37a toward the other side 37b of
the heat dissipating surface 31b of the base plate 31. The base
plate 31, when viewed in a transverse cross section, is so defined
that a resistance increasing portion 31c which increases a
resistance against the flow of the coolant is formed between the
sides 37a and 37b of the heat dissipating surface 31b.
[0052] The resistance increasing portion 31c consists of three
portions. In the first portion the heat dissipating surface 31b is
formed as an inclined surface 37d which goes up from a non-inclined
surface 37c at one side 37a in such a manner that the thickness of
the resistance increasing portion 31c gradually increases; in the
second portion that follows the inclined surface 37d, the heat
dissipating surface 31b is formed as a non-inclined surface 37e
which extends so that the thickness of the resistance increasing
portion 31c is constant; and in the third portion following the
non-inclined surface 37e, the heat dissipating surface 31b is
formed as an inclined surface 37f which goes down toward the other
side 37g in such a manner that the thickness of the resistance
increasing portion 31c gradually decreases. This arrangement
ensures that the coolant that enters the heat sink 3 from the
coolant inlet (the cylindrical member 35) is accelerated in
velocity at the resistance increasing portion 31c before being
discharged from the coolant outlet (the cylindrical member 36). As
a result, the heat exchange efficiency can be improved at
resistance increasing portion 31c, which in turn enhances the heat
exchange efficiency of the heat sink 3.
[0053] In this example, a plurality of radiation fins 38 are
integrally provided on the heat dissipating surface 31b of the base
plate 31 in the heat sink 3 to enhance the heat exchange
efficiency. The plurality of radiation fins 38 each have a
plate-like shape and contact with the inner surface of the top
plate 32. The plurality of radiation fins 38 extend in a first
direction (a lateral direction in the drawing) from the one side
37a where the coolant inlet (35) is situated toward the other side
37b where the coolant outlet (36) is situated, and are arranged
along the heat dissipating surface 31b at predetermined intervals
in a second direction (a vertical direction in the drawing)
perpendicular to the first direction. With the radiation fins 38
arranged in this manner, an efficient heat exchange can be realized
by the coolant flowing through flow passages 39 continuously formed
between two adjacent radiation fins 38, 38. In this case, the
coolant inlet (35) and the coolant outlet (36) pierce through the
top plate 32 in the thickness direction of the top plate at
positions corresponding to the central part of each side 37a, 37b
respectively. With this arrangement, the coolant that enters at the
coolant inlet (35) goes against the heat dissipating surface 31b
and diffuses, without excessive imbalance, into a space between the
top plate 32 and the base plate 31. The diffused coolant then
gathers evenly toward the coolant outlet (36) and goes out
therefrom. As a result, the entire heat sink 3 is cooled. In this
example, the positions of the both ends of the radiation fins 38 in
the first direction are so determined that the flow speeds of the
coolant do not vary excessively among flow passages 39 each formed
between two adjacent radiation fins 38, 38 as the coolant flows in
through the coolant inlet (35) and flows out of the coolant outlet
(36) through the flow passages 39. The cylindrical member 36 is
connected with one end of a pipe 9a, for example a metal pipe,
forming the first coolant path 9. The cylindrical member 35 is
connected with one end of a pipe 11a, for instance a metal pipe,
forming a part of the second coolant path 11. The other end of the
pipe 11a is connected to a cylindrical member 148 that forms a
liquid outlet of the motor-driven pump 13. A cylindrical member 147
forming a liquid inlet of the motor-driven pump 13 is connected to
a cylindrical member 81 forming a liquid outlet of the radiator 7
through a pipe 11b, such as a metal pipe forming a part of the
second coolant path 11.
[0054] The motor-driven pump 13 is installed in the second coolant
path 11 to give a moving energy to the coolant. FIG. 3A and FIG. 3B
represent a plan view and a front view of the motor-driven pump 13
respectively. FIG. 4 is a cross section taken along the line IV-IV
of FIG. 3B. FIG. 5 is an enlarged cross section taken along the
line V-V of FIG. 3B. The motor-driven pump 13 has a housing 131.
The housing 131 comprises a housing body 132 of synthetic resin and
a cover member 133 of synthetic resin. As shown in FIG. 5, the
housing body 132 comprises an outer cylindrical portion 135 with
open ends, a partition wall portion 136 provided inside, and formed
integrally with, the outer cylindrical portion 135, and a bottom
wall portion 137 fitted to one end (lower end) of the outer
cylindrical portion 135 to close that end. The partition wall
portion 136 comprises a first annular portion 138 formed integrally
with an inner wall of the outer cylindrical portion 135 and
protruding radially inwardly; a first inner cylindrical portion 139
provided integrally at an inner end of the first annular portion
138 and extending in a direction perpendicular to the direction in
which the first annular portion 138 extends (an axial direction); a
second inner cylindrical portion 140 situated inside the first
inner cylindrical portion 139 and extending axially; and a second
annular portion 141 situated at the cover member 133 side and
connecting the first and second inner cylindrical portions 139, 140
at one end. In this example, a major part of the second inner
cylindrical portion 140 forms a bearing holder 142. The other end
of the second inner cylindrical portion 140 is fitted to secure a
cap (seal member) 143 in a sealing structure and thus closed. In
this example, the partition wall portion 136 and the cap 143
combine to construct a waterproof structure that prevents a liquid
from getting into a space S. A stator 144 and a printed circuit
board 145 described later are received in the space S enclosed by a
part of the outer cylindrical portion 135, the cylindrical
partition wall portion 136, the bottom wall portion 137 and the cap
143.
[0055] As shown in FIG. 3, the cover member 133 has a hollow cover
member body 146 with its open end fused to the open end of the
outer cylindrical portion 135 (FIG. 5) of the housing body 132, a
cylindrical member 147 axially extending from the center of the
cover member body 146 to form a liquid inlet, and a cylindrical
member 148 tangentially extending from the side of the cover member
body 146 to form a liquid outlet.
[0056] Returning to FIG. 5, the stator 144 has a stator core 149
mounted on an outer periphery of the bearing holder 142, a
synthetic resin slot insulator 150 fitted to the stator core 149,
and a plurality of excitation coils 151 wound on poles of the
stator core 149 through the slot insulator 150. Leaders of the
excitation coils 151 are connected to a plurality of conductive
pins 152 secured to the slot insulator 150. The conductive pins 152
are fitted into connection through-holes provided in the circuit
board 145 that has an exciting current supply circuit for supplying
exciting currents to the excitation coils 151.
[0057] Inside the bearing holder 142, two bearings 154, 155 (in
this example, ball bearings) that rotatably support a shaft 153 are
fitted. These two bearings 154, 155 are inserted into the bearing
holder 142 from openings at both ends thereof.
[0058] A retainer 156 and a coil spring 157 are fitted over the end
of the shaft 153 on the cap 143 side. The coil spring 157 is
installed, being compressed between an inner race of the bearing
155 and the retainer 156. In this example, the coil spring 157 and
the retainer 156 together form a slip-off prevention mechanism.
With this construction, nothing stands in the way of the liquid
inflow into the space where an impeller rotates, which enhances the
pump performance.
[0059] A rotating body 158 is secured to an end of the shaft 153 at
the cover member 133 side. The rotating body 158 is made from a
magnetically permeable material and has a cylindrical peripheral
wall portion 159 and a closing wall portion 160 formed integrally
with the peripheral wall portion 159 so as to close one end of an
inner space enclosed by the peripheral wall portion 159. The end of
the shaft 153 is tightly fitted into a through-hole formed in the
center of the closing wall portion 160. A plurality of rotary side
magnetic poles 161 made from permanent magnets are secured onto the
inner surface of the peripheral wall portion 159 of the rotating
body 158. An impeller 162 is secured to the top of the closing wall
portion 160 of the rotating body 158. The impeller 162 has a blade
mounting portion 163 fixed to the closing wall portion 160 and a
plurality of blades 164 integrally provided at the surface of the
blade mounting portion 163. In this example, a reduced diameter
portion 159a is formed at one end of the peripheral wall portion
159 of the rotating body 158. An annular extension portion 165
which snugly fits over the outer periphery of the reduced diameter
portion 159a is integrally formed at the outer peripheral portion
of the blade mounting portion 163 of the impeller 162. In this
motor-driven pump, a rotor 166 is made of parts ranging from the
rotating body 158 to the extension portion 165. In this pump, the
rotor 166, the impeller 162 and the bearings 154, 155 are submerged
in the coolant. When the impeller 162 rotates, the pump draws in a
liquid through the liquid inlet (147) and discharges it from the
liquid outlet (148).
[0060] In this motor-driven pump 13, the stator core 144 is
situated on the outer periphery of the bearing holder 142, and the
rotor 166 rotates outside the stator core. This construction can
reduce the axial dimension of the motor-driven pump 13 and can also
enhance the pump performance by making the most of the inertia of
the rotor 166. Further, in this construction, since the liquid gets
into the interior of the bearing holder 142, heat from the stator
144 can also be released through the bearing holder 142 to the
liquid flowing through the interior of the pump. Further, because
the liquid getting into the bearing holder 142 functions as a
lubricant for the bearings 154, 155, there is no need to replenish
the lubricant to the bearings 154, 155, which significantly extends
the life of the motor-driven pump 13.
[0061] In this motor-driven pump 13, at least one liquid path 167
extending along the shaft 153 is formed between the inner
peripheral surface of the bearing holder 142 and the outer
peripheral surface of the two bearings 154, 155. In FIG. 5 only one
liquid path 167 is shown. The liquid path 167 allows the whole
interior of the bearing holder 142, including the space formed
between the two bearings 154, 155 in the bearing holder 142, to be
completely filled with the flowing liquid. The liquid path 167 can
be formed by forming at least one groove extending along the shaft
153 in at least either the inner peripheral surface of the bearing
holder 142 or the outer peripheral surface of the bearings 154,
155.
[0062] One or more (in this case, four) through-holes 168 piercing
therethrough in the thickness direction thereof to allow the
coolant to flow therethrough are formed on the closing wall portion
160 of the rotating body 158. Four through-holes 169 aligned with
the four through-holes 168 of the closing wall portion 160 are
formed on the blade mounting portion 163 of the impeller 162.
Forming these through-holes 168, 169 ensures a smooth flow of
liquid between the interior and the exterior of the rotating body
158.
[0063] FIG. 6A is a cross-sectional view showing another example of
a motor-driven pump 1013 used in the present invention. The
motor-driven pump 1013 has a smaller axial dimension than that of
the preceding example of the motor-driven pump 13 shown in FIG. 3
to FIG. 5. Regarding those parts of this motor-driven pump 1013
that are identical in construction with the corresponding parts of
the motor-driven pump 13 shown in FIG. 3 to FIG. 5, the explanation
of the parts is omitted here by indicating each reference number
added 1000 to the corresponding reference number shown in FIG. 3 to
FIG. 5. In this motor-driven pump 1013, three grooves 1167
continuously extending along a shaft 1153 are formed in that
portion of the inner peripheral surface of a bearing holder 1142
which faces the outer peripheral surface of the bearings 1154,
1155. These three grooves 1167 constitute liquid paths. The three
grooves 1167 are formed at equal intervals in the circumferential
direction of the shaft 1153, as shown in FIG. 6B. This arrangement
can eliminate a possibility that the presence of the three grooves
1167 may cause the centers of the bearings 1154, 1155 out of
alignment with the center of the bearing holder 1142. The grooves
1167 extend along the shaft 1153 and have a narrow elongate shape,
facing the outer peripheral surface of the two bearings 1154, 1155.
In this example, a housing body 1132 is not provided with a bottom
wall portion. A cap 1143 has an annular recess 1172 formed in the
outer peripheral portion thereof, in which an O-ring 1173 is fitted
to form a seal portion. The cap 1143 is attached with an end cover
1174 that engages the end of the bearing holder 1142. In other
respects, the construction of the motor-driven pump is essentially
the same as that of the motor-driven pump shown in FIG. 3 to FIG.
5.
[0064] FIG. 7 is a cross-sectional view showing still another
example of a motor-driven pump 2013 used in the present invention.
The motor-driven pump 2013, as with the motor-driven pump shown in
FIG. 6A, has a reduced axial dimension when compared with the
motor-driven pump 13 shown in FIG. 3 to FIG. 5. Regarding those
parts of this motor-driven pump 2013 that are identical in
construction with the corresponding parts of the motor-driven pump
13 shown in FIG. 3 to FIG. 5, the explanation of the parts is
omitted here by indicating each reference number added 2000 to the
corresponding reference number shown in FIG. 3 to FIG. 5. In this
motor-driven pump 2013, a blade mounting portion 2163 of an
impeller 2162 is provided with a cylindrical extended mounting
portion 2163a that extends along a peripheral wall portion 2159 of
a rotating body 2158. A plurality of blades 2164 may be formed so
as to extend continuously from over the blade mounting portion 2163
to over the cylindrical extended mounting portion 2163a. This
arrangement can make the most of the outer surface of the rotating
body 2158 in forming long blades, thereby enhancing the performance
of the motor-driven pump.
[0065] FIGS. 8A to 8D are a plan view, a front view, a left side
view and a bottom view of a radiator 7 which is used in a system
configuration of the embodiment of FIG. 1. This radiator 7 includes
ten liquid passages 71 arranged in parallel in a vertical direction
and bellows-like radiation fins 72 attached to the outer surfaces
of the liquid passages 71. Two liquid tanks 73, 74 are connected
with and communicate with both ends of the ten liquid passages 71,
and arranged on either side of the ten liquid passages 71,
respectively. On the both sides, with respect to the vertical
arrangement direction of the ten liquid passages 71, are provided
motor-driven mounting brackets 75, 76. The motor-driven mounting
brackets 75, 76 are formed by stamping and bending a metal plate.
They have a plurality of screw insertion projections 77 each formed
with a through-hole in which a mounting screw can be inserted. The
motor-driven mounting brackets 75, 76 have a plurality of holes 78,
79 as engaged portions respectively to which engaging pieces 56, 57
of the motor-driven fan 5 are fastened when fixing the fan 5. In
this radiator 7, the ten liquid passages 71 shown in FIG. 8B and
the radiation fins 72 together constitute a heat dissipating
portion 88.
[0066] The liquid tank 73 is provided with a cylindrical member 80
that constitutes a liquid inlet, and the liquid tank 74 with a
cylindrical member 81 constituting a liquid outlet. In this
radiator 7, as shown in FIG. 9, chambers in the two tanks 73, 74
are each divided into three sub-chambers 82a-82c and 83a-83c by two
partition walls 84 spaced in the direction of the parallel
arrangement of the ten liquid passages 71. In this example, the
sub-chamber 82a is communicably connected with upper two liquid
passages 71 at one end; the sub-chamber 83a is communicably
connected with upper four liquid passages 71 at the other end; the
sub-chamber 82b is communicably connected with third to sixth four
liquid passages 71 at one end; the sub-chamber 83b is communicably
connected with fifth to eighth four liquid passages 71 at the other
end; the sub-chamber 82c is communicably connected with seventh to
tenth four liquid passages 71 at one end; and the sub-chamber 83c
is communicably connected with ninth to tenth two liquid passages
71 at the other end. In other words, three sub-chambers 82a-82c and
83a-83c in each of the two tanks 73, 74 and the ten liquid passages
71 are connected with each other in such a manner that two liquid
passages 71 construct a winding liquid path between the liquid
inlet (80) and the liquid outlet (81). This arrangement enables a
predetermined amount of liquid to be cooled in a relatively short
period of time. It is also possible to connect a plurality of
sub-chambers in the two tanks to a plurality of liquid passages to
have only one liquid passage 71 serve as a liquid path winding
between the liquid inlet and the liquid outlet.
[0067] The liquid path forming method adopted in this radiator 7
may be expressed in the following generalized term. A chamber in
each of the two liquid tanks 73, 74 is divided, in a direction of
arrangement of the plurality of liquid passages 71, into m plus one
(m is an integer of one or more: three sub-chambers in this
embodiment) sub-chambers 82a-82c, 83a-83c by m (two partition walls
in this embodiment) partition walls 84. Then the sub-chambers
82a-82c, 83a-83c in each of the two liquid tanks and the plurality
of liquid passages 71 are connected with each other in such a
manner that one or more liquid passages (two passages in this
embodiment) construct a winding liquid path between the liquid
inlet 80 and the liquid outlet 81.
[0068] In this example, the two tanks 73, 74 are arranged so that
the sub-chambers 82a, 83a are positioned at the upper end and the
sub-chambers 82c, 83c are positioned at the lower end,
respectively. The sub-chamber 83a in the tank 74 is situated higher
than the sub-chamber 82a in the tank 73 and these sub-chambers are
formed in such a dimension and shape so as to allow a space 85 to
be defined therein that is not filled with the liquid. In this
arrangement, the air that may cause bubbles in the liquid stays in
the space 85, effectively preventing the air from getting into the
liquid to cause the bubbles which in turn causes reduced cooling
efficiency. A top part of the sub-chamber 83a in the tank 74 is
attached with a coolant resupply cap 86 for replenishing a
coolant.
[0069] As shown in FIG. 10, it is also possible to adopt a known
construction in which the interiors of the two tanks 73, 74 are not
divided by partition walls.
[0070] FIG. 11 shows the structure of another radiator. Regarding
FIG. 11, the explanation of the parts is omitted by adding 100 to
the corresponding number shown in FIG. 9. In this radiator 107, the
chamber in the liquid tank 173 is divided into three sub-chambers
182a-182c by two partition walls 184 spaced in the direction of the
parallel arrangement of the eight liquid passages 171. The chamber
in the other liquid tank 174 is divided into two sub-chambers 183a,
183b by a partition wall 184 spaced in the direction of the
parallel arrangement of the eight liquid passages 171. In this
example, the sub-chamber 182a is communicably connected with upper
two liquid passages 171 at one end; the sub-chamber 183a is
communicably connected with upper four liquid passages 171 at the
other end; the sub-chamber 182b is communicably connected with
third to sixth four liquid passages 71 at one end; the sub-chamber
183b is communicably connected with fifth to eighth four liquid
passages 171 at the other end; the sub-chamber 182c is communicably
connected with seventh to eighth two liquid passages 171 at one
end; the liquid inlet (a cylindrical member 180) and the liquid
outlet (a cylindrical member 181) are provided in sub-chambers
182a, 182c respectively. engaging pieces engaging pieces engaged
portions engaging pieces engaged portions engaging pieces engaging
pieces.
[0071] The structure of sub-chambers of the radiator 107 may be
expressed in the following generalized term. A chamber in the one
liquid tank 173 is divided, in a direction of arrangement of the
plurality of liquid passages 171, into n plus one (n is an integer
of two or more: three sub-chambers in this embodiment) sub-chambers
182a-182c by n (two partition walls in this embodiment) partition
walls 184. The other liquid tank 174 is divided, in a direction of
arrangement of the plurality of liquid passages 171, into n (two
sub chambers in this embodiment) sub chambers 183a, 183b by n-1
(one partition walls in this embodiment) partition walls 184. Then
the sub-chambers 183a, 183b in the two liquid tanks 173, 174 and
the plurality of liquid passages 171 are connected with each other
in such a manner that one or more of the liquid passages (two
passages in this embodiment) construct a winding liquid path
winding between the liquid inlet 180 and the liquid outlet 181.
[0072] FIGS. 12A to 12D are a front view, a left side view, a plan
view and a partly cutaway front view of the motor-driven fan 5 used
for air-cooling the radiator 7. The motor-drive fan 5 has an air
channel body 51, an impeller 52 and a motor 53. At one end, the air
channel body 51 has a suction port 54 facing the front of the heat
dissipating portion 88 of the radiator 7 shown in FIG. 8 and, at
the other end, a discharge port 55. The air channel body 51 has six
engaging pieces 56, 57 integrally formed with an outer peripheral
portion on the side of the suction port 54. The three engaging
pieces 56 are so shaped that their front end portions are inserted
and locked into three holes 79 provided, as engaged portions, at
the mounting bracket 76 of the radiator 7. The three engaging
pieces 57 are hook-shaped so that their front end portions are
inserted and locked into three holes 78 provided, as engaged
portions, at the mounting bracket 75 of the radiator 7. When the
motor-driven fan 5 is to be mounted at the radiator 7, the engaging
pieces 56 are inserted into the holes 79, and then the engaging
pieces 57 are inserted into the holes 78 as being transformed.
[0073] The impeller 52 has a cup-shaped member 58 rotated by the
motor 53 and seven blades 59 integrally mounted at a peripheral
wall portion of the cup-shaped member 58. Edges 60 of the seven
blades 59 facing the front of the heat dissipating portion 88 of
the radiator 7 are sloping gradually away from the dissipating
portion 88 as each of the edges extends in a radially outward
direction from the rotating center of the impeller 52. This
structure can reduce noise. In this motor-driven fan 5, three webs
61 connecting the housing 62 of the motor 53 and the end portion of
the air channel body 51 on the side of the discharge port 55 are
situated outside the discharge port 55. In other words, the end
portion on the side of the discharge port is lower than the
uppermost surface of the housing 62 of the motor 53. This
arrangement can enhance an air blowing performance and reduce noise
when compared with a construction in which the webs 61 are situated
on the inner side of the discharge port 55.
[0074] The motor 53 rotates in such a direction that the impeller
52 is rotated to draw in air through the suction port 54 and
discharge air through the discharge port 55. The construction that
draws in air by the motor-driven fan 5 at the heat dissipating
portion 88 of the radiator 7, as in this example, can draw out
heated air through the heat dissipating portion 88 without
unnecessarily increasing the rotation speed of the motor-driven fan
5 even when the heat dissipating portion 88 of the radiator 7 is
complicatedly constructed. This construction can also reduce
noise.
[0075] With the present invention, even when the amount of heat
generated by electronic components increases, the heat sink can be
positively cooled by means of a coolant, thereby significantly
enhancing the cooling performance when compared with a conventional
construction in which the heat sink is cooled only by means of
air.
[0076] Further, the present invention is not limited to these
embodiments, but various variations and modifications may be made
without departing from the scope of the present invention.
* * * * *