U.S. patent application number 10/823286 was filed with the patent office on 2005-01-27 for heat radiator.
Invention is credited to Ashitani, Hiromasa, Nakano, Masao, Tsujimoto, Tsutomu.
Application Number | 20050016720 10/823286 |
Document ID | / |
Family ID | 34074637 |
Filed Date | 2005-01-27 |
United States Patent
Application |
20050016720 |
Kind Code |
A1 |
Ashitani, Hiromasa ; et
al. |
January 27, 2005 |
Heat radiator
Abstract
A heat radiator includes a heat absorbing element, a heat
radiating element, and a pump connected with the heat absorbing
element and the heat radiating element to define a closed circuit.
The pump circulates a refrigerant through the closed circuit. The
heat absorbing element includes a heat-exchanging portion for
transferring heat generated by a heating element to the
refrigerant, a cover joined to a peripheral edge of the
heat-exchanging portion to define a refrigerant flow channel
therebetween, and one or more connecting members disposed within
the refrigerant flow channel and having opposite ends joined to the
heat-exchanging portion and the cover, respectively, to connect the
heat-exchanging portion and the cover with each other.
Inventors: |
Ashitani, Hiromasa;
(Otsu-shi, JP) ; Nakano, Masao; (Koka-gun, JP)
; Tsujimoto, Tsutomu; (Koka-gun, JP) |
Correspondence
Address: |
RATNERPRESTIA
P O BOX 980
VALLEY FORGE
PA
19482-0980
US
|
Family ID: |
34074637 |
Appl. No.: |
10/823286 |
Filed: |
April 13, 2004 |
Current U.S.
Class: |
165/170 ;
165/80.4; 257/E23.098 |
Current CPC
Class: |
F28D 2021/0029 20130101;
H01L 23/473 20130101; H01L 2924/00 20130101; H01L 2924/0002
20130101; H01L 2924/0002 20130101 |
Class at
Publication: |
165/170 ;
165/080.4 |
International
Class: |
F28F 007/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 22, 2003 |
JP |
2003-277384 |
Claims
What is claimed is:
1. A heat radiator comprising: a heat absorbing element; a heat
radiating element; a pump connected with said heat absorbing
element and said heat radiating element to define a closed circuit,
said pump circulating a refrigerant through the closed circuit; and
said heat absorbing element comprising: a heat-exchanging portion
adapted to transfer heat generated by a heating element to the
refrigerant; a cover joined to a peripheral edge of said
heat-exchanging portion to define a refrigerant flow channel
therebetween; and at least one connecting member disposed within
the refrigerant flow channel and having opposite ends joined to
said heat-exchanging portion and said cover, respectively, to
connect said heat-exchanging portion and said cover with each
other.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a heat radiator for
radiating heat from a heating element such as a semiconductor
element mounted in an electronic appliance such as a computer or
the like.
[0003] 2. Description of the Related Art
[0004] Japanese Laid-Open Patent Publication No. 2001-24372
discloses a conventional heat radiator, which is mounted in a
notebook computer to radiate heat from a heating element in the
computer.
[0005] As shown in FIG. 1, the heat radiator in the computer 50
includes a heat absorbing element 52 attached fast to a heating
element 54 mounted in the computer 50, a pump 56 fluid connected to
the heat absorbing element 52, and a heat radiating element 58
fluid connected to the heat absorbing element 52 and the pump 56,
all connected in series to define a refrigerant circulating cycle.
A typical refrigerant employed in this refrigerant circulating
cycle is an easy-to-handle water-based one, and the pressure inside
the refrigerant circulating cycle is relatively low of being
approximately atmospheric pressure.
[0006] However, the heat radiator of the above-described
construction is not suited to the use of a high-pressure
refrigerant such as a fluorocarbon-based refrigerant, a latent heat
effect of which is effectively utilized to further reduce the heat
resistance to enhance the heat radiating performance. Because the
pressure-resistant strength of the heat absorbing element 52 is not
taken into consideration, it is likely that the use of the
high-pressure refrigerant may deform the surface of the heat
absorbing element 52 to which the heating element 54 is joined,
giving rise to a possibility of lowering the heat radiating
performance.
SUMMARY OF THE INVENTION
[0007] The present invention has been developed to overcome the
above-described disadvantage.
[0008] It is accordingly an objective of the present invention to
provide a heat radiator having a heat absorbing element suited to
the use of a high-pressure refrigerant.
[0009] In accomplishing the above and other objectives, the heat
radiator according to the present invention includes a heat
absorbing element, a heat radiating element, and a pump connected
with the heat absorbing element and the heat radiating element to
define a closed circuit. A refrigerant filled in the closed circuit
is circulated through the closed circuit by the pump. The heat
absorbing element includes a heat-exchanging portion for
transferring heat generated by a heating element to the
refrigerant, a cover joined to a peripheral edge of the
heat-exchanging portion to define a refrigerant flow channel
therebetween, and at least one connecting member disposed within
the refrigerant flow channel and having opposite ends joined to the
heat-exchanging portion and the cover, respectively, to connect the
heat-exchanging portion and the cover with each other.
[0010] The presence of the connecting member within the refrigerant
flow channel reduces the surface areas of the heat-exchanging
portion and the cover, to which the pressure of the high-pressure
refrigerant flowing through the refrigerant flow channel is
applied, and also reduces the load applied to such surface areas,
thus preventing the surface of the heat-exchanging portion
confronting the heating element from lowering in flatness.
[0011] The cover is joined to the heat-exchanging portion by
melting a brazing filler material within a furnace. Although a high
temperature inside the furnace reduces the strength of the heat
absorbing element, the connecting member acts to maintain the
strength of the heat absorbing element above a predetermined level
without deforming the surface of the heat absorbing element to
which the heating element is joined.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The above and other objectives and features of the present
invention will become more apparent from the following description
of a preferred embodiment thereof with reference to the
accompanying drawings, throughout which like parts are designated
by like reference numerals, and wherein:
[0013] FIG. 1 is a perspective view of a notebook computer having a
conventional heat radiator mounted therein;
[0014] FIG. 2 is a circuit diagram of a heat radiator embodying the
present invention;
[0015] FIG. 3A is a front elevational view, partly in section, of a
heat absorbing element mounted in the heat radiator shown in FIG.
2; and
[0016] FIG. 3B is a section taken along line A-A in FIG. 3A.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0017] This application is based on an application No. 2003-277384
filed Jul. 22, 2003 in Japan, the content of which is herein
expressly incorporated by reference in its entirety.
[0018] Referring now to the drawings, there is shown in FIG. 2 a
circuit diagram of a heat radiator R embodying the present
invention. The heat radiator R shown in FIG. 2 includes a heat
absorbing element 2, a heat radiating element 4, and a pump 6, all
connected in series via piping 8 to define a closed circuit. A
high-pressure refrigerant filled in this closed circuit circulates
through the heat absorbing element 2, the heat radiating element 4,
and the pump 6 in this order.
[0019] FIG. 3A depicts the heat absorbing element 2 partly in
section, and FIG. 3B is a section taken along line A-A in FIG.
3A.
[0020] As shown in FIG. 3A, the heat absorbing element 2 confronts
and is attached fast to a heating element 10 such as, for example,
a semiconductor element mounted in an electronic appliance such as,
for example, a computer. The heat absorbing element 2 receives heat
Qin generated by the heating element 10 via a coating film 12
interposed between the heating element 10 and a heat-exchanging
portion 14. The heat-exchanging portion 14 is made of a material
having a high thermal conductivity such as, for example, copper,
aluminum or the like. The heat Qin received by the heat absorbing
element 2 is transmitted to the high-pressure refrigerant via the
heat-exchanging portion 14. The high-pressure refrigerant so
supplied with the heat Qin is carried into the heat radiating
element 4, which is then cooled by a fan 16 juxtaposed therewith.
As a result of cooling by the fan 16, the high-pressure refrigerant
exhausts heat Qout to the open air. The high-pressure refrigerant
having exhausted the heat Qout returns to the pump 6 again, thus
forming a closed cycle.
[0021] A typical example of the high-pressure refrigerant is a
fluorocarbon-based refrigerant known as R134. When this refrigerant
is used in a heat radiator of the type referred to above, the
refrigerant comes to range generally from 0.degree. C. to
95.degree. C. In this temperature range, a latent heat effect of
the high-pressure refrigerant is utilized that is brought about by
a change in phase between a liquid phase and a vapor phase of the
refrigerant, making it possible to realize a high heat-exchanging
performance during the heat absorbing and radiating processes and
to reduce the heat resistance of the entire heat radiator R. Also,
in the above temperature range, the refrigerant pressure becomes
high enough to reach approximately 3 MPa and, hence, the
pressure-resistant strength of the heat radiator R is
important.
[0022] The heat absorbing element 2 includes, in addition to the
heat-exchanging portion 14, a cover 18 joined to a peripheral edge
of the heat-exchanging portion 14 to define a refrigerant flow
channel 20 therebetween, an inlet tube 22 joined to the
heat-exchanging portion 14, and an outlet tube 24 joined to the
heat-exchanging portion 14 on the side opposite to the inlet tube
22. The refrigerant is introduced into the heat absorbing element 2
through the inlet tube 22 and discharged therefrom through the
outlet tube 24. The cover 18 is joined to the heat-exchanging
portion 14 by melting a brazing filler material within a furnace.
Considering the properties of the brazing filler material, the
temperature inside the furnace is required to reach approximately
900.degree. C. Accordingly, if both the heat-exchanging portion 14
and the cover 18 are made of a like material such as copper or the
like, the pressure-resistant strength of the heat absorbing element
2 considerably reduces, and it is likely that the use of the
high-pressure refrigerant may deform the surface of the heat
absorbing element 2 to which the heating element 10 is joined. If
the flatness of such surface is not maintained, the thickness of
the coating film 12 on which the thermal conduction depends
increases partially, resulting in an increase in heat
resistance.
[0023] In the practice of the present invention, the heat absorbing
element 2 includes one or more (four in FIG. 3B) connecting members
26 disposed within the refrigerant flow channel 20 and having
opposite ends joined to the heat-exchanging portion 14 and the
cover 18, respectively, to connect them. Because the connecting
members 26 receive the pressure of the refrigerant inside the
refrigerant flow channel 20, the pressure applied to the opposing
surfaces of the heat-exchanging portion 14 and the cover 18 that
are exposed to the refrigerant flow channel 20 reduces, enhancing
the bending strength of the heat-exchanging portion 14 and
preventing the surface of the heat-exchanging portion 14
confronting the heating element 10 from lowering in flatness.
[0024] Although the present invention has been fully described by
way of examples with reference to the accompanying drawings, it is
to be noted here that various changes and modifications will be
apparent to those skilled in the art. Therefore, unless such
changes and modifications otherwise depart from the spirit and
scope of the present invention, they should be construed as being
included therein.
* * * * *