U.S. patent application number 12/421749 was filed with the patent office on 2009-12-10 for electronic apparatus cooling device.
Invention is credited to Hironori Oikawa.
Application Number | 20090301692 12/421749 |
Document ID | / |
Family ID | 41399223 |
Filed Date | 2009-12-10 |
United States Patent
Application |
20090301692 |
Kind Code |
A1 |
Oikawa; Hironori |
December 10, 2009 |
Electronic Apparatus Cooling Device
Abstract
A compact, low-cost electronic apparatus cooling device which
provides a high heat receiving performance with less transfer of
the heat of an exothermic body to a pump. In the device, a heat
receiving part has fins in a given area of a plate-like base and
the height of the fins is almost equal to the thickness of the base
which surrounds them. A pressure member with an opening covers part
of the top of the fins and part of the base. Refrigerant flows in
from part of the top of the fins in contact with the opening of the
pressure member and flow out from part of the top of the fins not
covered by the pressure member.
Inventors: |
Oikawa; Hironori; (Hadano,
JP) |
Correspondence
Address: |
ANTONELLI, TERRY, STOUT & KRAUS, LLP
1300 NORTH SEVENTEENTH STREET, SUITE 1800
ARLINGTON
VA
22209-3873
US
|
Family ID: |
41399223 |
Appl. No.: |
12/421749 |
Filed: |
April 10, 2009 |
Current U.S.
Class: |
165/104.31 |
Current CPC
Class: |
H01L 2924/3011 20130101;
H01L 23/473 20130101; H01L 2924/0002 20130101; H01L 2924/0002
20130101; H01L 2924/00 20130101 |
Class at
Publication: |
165/104.31 |
International
Class: |
F28D 15/00 20060101
F28D015/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 6, 2008 |
JP |
2008-149469 |
Claims
1. An electronic apparatus cooling device which cools an exothermic
body by heat transfer of refrigerant, comprising: a heat receiving
part including: a base for receiving heat generated by the
exothermic body; a pressure member with an opening, covering part
of the base and being located opposite to the exothermic body; and
a flow channel allowing the refrigerant to flow therein; a heat
radiator for radiating heat absorbed by the refrigerant; and a pump
for circulating the refrigerant between the heat receiving part and
the heat radiator, wherein in the flow channel of the heat
receiving part, the refrigerant flows in through the opening of the
pressure member and flow out from the periphery of the pressure
member in places other than the opening.
2. An electronic apparatus cooling device which cools an exothermic
body by heat transfer of refrigerant, comprising: a heat receiving
part including: a plate-like base for receiving heat generated by
the exothermic body; fins with a height almost equal to the height
of the surrounding base, located in an area of the base, opposite
to the exothermic body; a pressure member with an opening, covering
part of the top of the fins and part of the base; and a flow
channel allowing the refrigerant to flow therein; a heat radiator
for radiating heat absorbed by the refrigerant; and a pump for
circulating the refrigerant between the heat receiving part and the
heat radiator, wherein in the flow channel of the heat receiving
part, the refrigerant flows in from the top of the fins in the
opening of the pressure member and flows out from the top of the
fins on the periphery of the pressure member in places other than
the opening.
3. The electronic apparatus cooling device according to claim 2,
wherein the heat receiving part and the pump are integrated by
joining them vertically through the pressure member in a
water-tight manner; and wherein the pump includes a first suction
port to suck the refrigerant into the pump, a first discharge port
to discharge the refrigerant to the outside of the pump, a second
suction port to suck in the refrigerant from the heat receiving
part, and a second discharge port with an end face opposite to the
heat receiving part to discharge the refrigerant to the heat
receiving part.
4. The electronic apparatus cooling device according to claim 3,
further comprising: a partition for partitioning a pump chamber for
circulation of refrigerant in the pump, wherein the first suction
port and the second discharge port are located in a first area
partitioned by the partition; and wherein the second suction port
and the first discharge port are located in a second area
partitioned by the partition.
5. The electronic apparatus cooling device according to claim 2,
wherein the pressure member uses a gel sheet which remains flexible
in an ambient temperature range in which normal operation of the
exothermic body is guaranteed.
Description
CLAIM OF PRIORITY
[0001] The present application claims priority from Japanese patent
application serial no. JP 2008-149469, filed on Jun. 6, 2008, the
content of which is hereby incorporated by reference into this
application.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to cooling devices for
electronic apparatuses incorporating semiconductor integrated
circuits and more particularly to a cooling device which
efficiently cools the semiconductor integrated circuit of an
electronic apparatus.
[0004] 2. Description of the Related Art
[0005] Recent electronic apparatuses incorporate high performance
semiconductor integrated circuits as typified by CPUs used in
personal computers. Mainly because of the demand for higher
performance in electronic apparatuses, there is a rapidly growing
tendency that such semiconductor ICs are higher in speed and more
integrated than former ones and generate more heat. However, if the
temperature exceeds a given level, semiconductor ICs not only may
fail to maintain their inherent performance but also may break down
due to excessive heat. For this reason, it is necessary to cool the
semiconductor ICs in electronic apparatuses by some kind of
means.
[0006] A general method for cooling a semiconductor IC of an
electronic apparatus is an air-cooling system in which the
semiconductor IC is thermally connected with a heat sink and the
heat sink is cooled by a fan which blows air to the sink. In this
air cooling system, however, in order to increase the cooling
performance in response to rise in the temperature of an exothermic
body, a large high-speed fan must be installed to increase the air
flow rate. On the other hand, as the uses of electronic apparatuses
are more diversified, portable compact cooling device models have
been developed at an accelerated pace. This means that the
semiconductor IC cooling device of an electronic apparatus must
feature compactness and high performance and thus an air cooling
type device may not meet these requirements. For this reason, the
liquid cooling system which provides a higher cooling performance
by heat transfer of liquid refrigerant is drawing attention.
[0007] However, the problem with this liquid cooling system is to
reduce the device size and lower the cost because it uses more
components than the air cooling system.
[0008] One approach toward a smaller and less costly liquid cooling
device may be integration of various parts. For example, JP-A No.
2005-142191 and JP-A No. 2007-35901 disclose techniques to
integrate a heat receiving part and a pump. The former document
describes a cooling device which does not use heat radiating fins.
The latter document describes a cooling device which uses heat
radiating microfins.
SUMMARY OF THE INVENTION
[0009] For the heat receiving components of the heat exchanger in
the liquid cooling system, the above technical problem with the
related art must be solved in order to achieve compactness and cost
reduction.
[0010] In the cooling device disclosed in JP-A No. 2005-142191,
part of the casing is made of a metal with a high thermal
conductivity and this part is in contact with an exothermic body to
receive heat. However, from the viewpoint of the ability to receive
heat, this heat receiving structure may be lower in heat receiving
performance than a heat receiving structure dedicated to heat
reception, such as an elaborate finned structure. Besides, another
problem is that heat is easily transferred from the exothermic body
to the pump and the service life of the pump is unfavorably
affected.
[0011] On the other hand, the cooling device disclosed in JP-A No.
2007-35901 uses microfins for the heat receiving part. In this
case, since the flow channel resistance between fins is high, if
fitting or contact with the casing is inadequate, refrigerant may
flow not between fins but flow in gaps in the fitting or contact
area, resulting in a considerable deterioration in the heat
receiving performance. Also, when the fins are smaller, the
distance between the exothermic body and the fin top is shorter, so
there is a problem that the heat of the exothermic body is easily
transferred to the pump through the fins. However, the technique
does not suggest any concrete means to solve these problems.
[0012] An object of the present invention is to solve the above
problems and provide a compact electronic apparatus cooling device
which has a high heat receiving performance and hardly causes heat
transfer from the exothermic body to the pump.
[0013] In order to achieve the above object, according to one
aspect of the present invention, an electronic apparatus cooling
device which cools an exothermic body by heat transfer of
refrigerant, includes a heat receiving part which has a base for
receiving heat generated by the exothermic body, a pressure member
with an opening, covering part of the base and being located
opposite to the exothermic body, and a flow channel allowing the
refrigerant to flow therein. The device also includes a heat
radiator for radiating heat absorbed by the refrigerant, and a pump
for circulating the refrigerant between the heat receiving part and
the heat radiator. In the flow channel of the heat receiving part,
the refrigerant flows in through the opening of the pressure member
and flows out from the periphery of the pressure member in places
other than the opening.
[0014] According to another aspect of the invention, an electronic
apparatus cooling device includes a heat receiving part which has a
plate-like base for receiving heat generated by the exothermic
body, fins with a height almost equal to the height of the
surrounding base, located in an area of the base, opposite to the
exothermic body, a pressure member with an opening, covering part
of the top of the fins and part of the base, and a flow channel
allowing the refrigerant to flow therein. The device also includes
a heat radiator for radiating heat absorbed by the refrigerant and
a pump for circulating the refrigerant between the heat receiving
part and the heat radiator. In the flow channel of the heat
receiving part, the refrigerant flows in from the top of the fins
in the opening of the pressure member and flows out from the top of
the fins on the periphery of the pressure member in places other
than the opening.
[0015] According to the present invention, it is possible to
prevent deterioration in the heat receiving performance
attributable to compactness. The invention also produces an
advantageous effect that the heat of the exothermic body is hardly
transferred to the pump. Consequently, a compact high-performance
electronic apparatus cooling device can be offered, contributing to
improvement in the performance of an electronic apparatus such as a
small personal computer.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] These and other features, objects and advantages of the
present invention will become more apparent from the following
description when taken in conjunction with the accompanying
drawings wherein:
[0017] FIGS. 1A and 1B show the heat receiving part and pump of a
cooling device according to an embodiment of the present invention,
in which FIG. 1A is a perspective view and FIG. 1B is a sectional
view;
[0018] FIG. 2 is a perspective view of the heat receiving part
according to the embodiment;
[0019] FIG. 3 is sectional view of another embodiment of the
present invention;
[0020] FIG. 4 shows an example of the configuration of an
electronic apparatus incorporating a cooling device according to
the present invention;
[0021] FIGS. 5A and 5B are perspective views of a pressure member
of a heat receiving part according to an embodiment of the
invention, in which FIGS. 5A is one example thereof and FIG. 5B is
another example thereof;
[0022] FIGS. 6A and 6B show the heat receiving part and pump of a
cooling device according to another embodiment, in which FIG. 6A is
a perspective view and FIG. 6B is a sectional view; and
[0023] FIGS. 7A and 7B show the heat receiving part and pump of a
cooling device according to a further embodiment, in which FIG. 7A
is a perspective view and FIG. 7B is a sectional view.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0024] Next, the preferred embodiments of the present invention
will be described referring to the accompanying drawings.
[0025] FIG. 4 shows an example of the configuration of an
electronic apparatus incorporating a cooling device according to
the present invention.
[0026] The electronic apparatus 401 includes a circuit board 402, a
power supply 410, and an HDD 411. The circuit board 402 has an
exothermic body 403 such as a semiconductor device.
[0027] The cooling device 404 for the exothermic body 403 includes
the following components. A heat receiving part 405 is thermally
connected with the exothermic body 403 and the refrigerant which
flows inside it absorbs the heat by heat transfer. A heat radiator
408 radiates the heat absorbed by the refrigerant to the outside of
the electronic apparatus 401 by cooling air flowing through core
tubes, radiating fins or the like. A pump 406, integral with the
heat receiving part 405, circulates the refrigerant between the
heat receiving part 405 and the heat radiator 408. A tank 409
stores the refrigerant for the cooling device 404 and piping 407
connects the pump 406 and the heat radiator 408 to enable the
refrigerant to circulate between them.
[0028] The electronic apparatus 401 is not a specific type of
apparatus and this embodiment assumes that the exothermic body 403
is a semiconductor device. However, the exothermic body is not
limited to a semiconductor device but the cooling device 404 may
cool an HDD or the like. In this embodiment, although the tank 409
is a separate unit, instead it may be integral with the heat
radiator 408.
[0029] The heat receiving part 405 and pump 406 of the cooling
device 404 according to the present invention are described below
in detail. FIGS. 1A and 1B show the heat receiving part and pump of
the cooling device according to an embodiment of the present
invention. FIG. 1A is a perspective view of the device as seen from
the pump side. FIG. 1B is a sectional view taken along the line
A-A' of FIG. 1A. In FIG. 1A, part of the fins 202 which is hidden
behind a pressure member 203 is represented by broken lines.
[0030] The pump 406 in this embodiment is a vortex pump which has a
first suction port 101 for sucking refrigerant and a first
discharge port 102 for discharging refrigerant. These communicate
with the piping 407. It also includes a second discharge port 104
and a second suction port 105 which are characteristic of the
present invention. The openings of these ports face the heat
receiving part 405. Partitions 103 and 106 are located between the
first suction and discharge ports and between the second suction
and discharge ports respectively. Due to these partitions, the
suction and discharge ports perform their respective functions. A
magnetized impeller 107 is rotated by a coil 109 and a driver board
110; as the impeller 107 rotates, its blade 108 moves the
refrigerant and generates a liquid flow. In the pump 406, the
refrigerant which has flown in through the first suction port 101
flows out through the second discharge port 104, passes on the heat
receiving part 405, and again flows in through the second suction
port 105 and flows out through the first discharge port 102.
[0031] The heat receiving part 405 joined to the pump 406 is
described below. FIG. 2 is a perspective view of the heat receiving
part 405. Arrows 206 and 208 denote directions of refrigerant
flows. 207 represents the central top of the fins 202. Part of the
fins 202 which is hidden by the pressure member 203 or located
inside the heat receiving part 405 is represented by broken
lines.
[0032] The heat receiving part 405 includes a base 201, fins 202,
and a pressure member 203. The top of the fins 202 is almost flush
with the upper surface of the base 201. More specifically, the
height difference between the top of the fins 202 and the upper
surface of the base 201 which is produced in the process of making
the fins 202 is so small that it is absorbed by the pressure member
203.
[0033] The bottom 205 of the fins 202 is thinner than the base 201.
The pressure member 203 lies over the base 201 and the fins 202 and
has an opening 204. The pressure member 203 is intended to
eliminate the gap between the pump and the fins even if the fins
202 are not uniform in size (height, etc) and ensure that
refrigerant flows to the fins smoothly. Therefore, the pressure
member 203 is made of a flexible material with a sufficient heat
resistance to withstand the heat of the fins. One example of the
material is a gel sheet which remains flexible in a wide
temperature range. If the exothermic body 403 is a semiconductor
device, it is desirable that the material retains its flexibility
in a temperature range from -20.degree. C. to 100.degree. C., an
ambient temperature range in which normal operation of the device
is guaranteed. Consequently the height difference between the top
of the fins 202 and the upper surface of the base 201 can be
absorbed by the pressure member 203 in a desired temperature
range.
[0034] How refrigerant flows in the heat receiving part 405 is
explained below. The refrigerant 206 flowing out through the second
discharge port 104 of the pump 406 flows along the opening 204 of
the pressure member 203 into the central top 207 of the fins 202.
The refrigerant which has flowed into the fins 202 springs out from
the periphery of the pressure member 203. The refrigerant 208 which
has sprung out is forced to flow into the second suction port 105
of the pump 406 because the periphery is sealed by an O ring 111.
As explained above, even if the refrigerant inflow and outflow
ports of the heat receiving part 405 are located not over the fins
but over the base, the refrigerant can flow in and out in over the
fins, contributing to compactness. According to the present
invention, the heat receiving part 405 can easily cope with any
change in the position of the second discharge port 104. For
example, as shown in FIGS. 5A and 5B, even if the second discharge
port 104 is not in the position shown in FIG. 5A but in the
position shown in FIG. 5B, the shape of the pressure member 203 can
be modified as shown in FIG. 5B to cope with this change.
[0035] Therefore, the second discharge port 104 can be located in a
position convenient for the pump. Also, the second suction port 105
may be in any position unless the pressure member 203 overlaps it.
This permits wider design latitude and the pump and the heat
receiving part can be integrated in the most compact manner
possible.
[0036] As described earlier, the absence of gaps between the pump
and the fins helps solve the problem that refrigerant may flow in
places other than the fins and cause deterioration in the heat
receiving performance.
[0037] Also as described earlier, the second discharge port 104
further increases the cooling effect as it faces the heat receiving
part 405.
[0038] In this embodiment, the thickness of the base 201 is 1.5 mm
and that of the pressure member 203 is 0.5 mm. Since the second
discharge port 104 and second suction port 105 of the pump 406 are
simple openings, the overall pump thickness is the same as the
thickness of the pump as a single unit. Hence, the thickness of the
combination of the single pump unit and heat receiving part is only
2 mm larger than the thickness of the single pump unit.
[0039] In the conventional techniques, there is a possibility that
the heat of the exothermic body is easily transferred to the pump
side through the fins and particularly when the pump shaft 112 is
located near the fins, the shaft and its surroundings may
deteriorate quickly and the service life of the pump maybe
shortened. On the other hand, in this embodiment, the pressure
member 203 is made of a material with a lower thermal conductivity
than metal, such as a gel sheet as described earlier and it has an
opening 204 in the center. Since refrigerant flows in the opening
204, the heat of the heat receiving part is not directly
transferred to the pump. Therefore, the embodiment provides a
solution to the problem that the heat of the exothermic body may be
transferred to the pump. In practice, the pump temperature is 3 to
6 degrees lower than when the pressure member 203 is not
employed.
[0040] In the above embodiment, the fins 202 are like a plate;
however the fins are not limited thereto. For example, an array of
pin-like fins may be used instead. Also the pump is not limited to
the vortex pump as mentioned above but it may be a centrifugal pump
or gear pump.
[0041] FIG. 3 shows an embodiment which uses a gear pump. In the
figure, 301 represents internal gear and 302 represent external
gear. The other elements which may be identical to those shown in
FIGS. 1A and 1B are designated by the same reference numerals. In
the gear pump shown in FIG. 3, the internal gear 301 and the
external gear 302 engage with each other while rotating to move the
liquid. As in the foregoing embodiment, this pump has a second
discharge port 104 and a second suction port 105 for connection
with the heat receiving part in addition to a first suction port
(not shown) and a first discharge port 102 for connection with the
outside. The top of the fins 202 is almost flush with the base 201
and the pressure member 203 lies between the fins 202 and the
second discharge port 104. As in the foregoing embodiment, this
structure ensures that refrigerant flows to the microfins and
prevents deterioration in the heat receiving performance, curbs
transfer of the heat of the fins to the pump and permits contact
with the heat receiving part with virtually no size increase from
the size of the single pump unit.
[0042] Although the above explanation assumes that many fins are
provided at short intervals as illustrated in FIGS. 1A and 1B, this
is not a restrictive condition. Other embodiments are illustrated
in FIGS. 6A, 6B, 7A and 7B. These are perspective views and
sectional views taken in the same way as FIGS. 1A and 1B. The same
elements are designated by the same reference numerals.
[0043] FIGS. 6A and 6B show that the device has three fins 202.
Even when a small number of fins are provided at long intervals as
in this example, the present invention can be applied and produces
a similar effect. If the fins are thicker than those in FIGS. 1A
and 1B, the heat radiation effect will be larger.
[0044] FIGS. 7A and 7B show that the device has no fins. In this
example, a gap is more easily generated between the pressure member
203 and the pump than in the device shown in FIGS. 1A and 1B. If
this is a problem, it can be solved by using an adhesive agent.
Refrigerant flows out through the second discharge port 104 into
the opening 204 of the pressure member and particularly cools the
bottom 205 of the base before flowing out from the periphery of the
pressure member 203 and being sucked into the pump through the
second suction port 105. As in FIGS. 1A and 1B, the present
invention can be applied to this structure and a similar effect can
be produced.
[0045] Directions in which refrigerant flows are indicated by
arrows 206 and 208 in FIG. 2. However, even when refrigerant flows
in directions opposite to them, a cooling effect can be produced.
In order to reduce temperature rise in the pump 406 including the
pump shaft 112, it is recommended that refrigerant should flow in
the directions as shown in FIG. 2.
[0046] As explained so far, according to the present invention, the
positions of the refrigerant suction and discharge ports of a small
high-performance heat receiving part can be freely determined, so
the heat receiving part and the pump can be easily integrated and
in integration of the pump and the heat receiving part with
microfins, a gap between the microfins and the pump, which could
lower the heat receiving performance, can be easily eliminated.
Transfer of the heat of the fins to the pump is curbed, and the
service life of the pump is not shortened. In addition, since the
size of the combination of the pump and heat receiving part is
virtually no larger than the pump itself, a high-performance
compact liquid cooling device can be realized at low cost.
[0047] While we have shown and described several embodiments in
accordance with our invention, it should be understood that
disclosed embodiments are susceptible of changes and modifications
without departing from the scope of the invention. Therefore, we do
not intend to be bound by the details shown and described herein
but intend to cover all such changes and modifications that fall
within the ambit of the appended claims.
* * * * *