Electricity: electrical systems and devices – Housing or mounting assemblies with diverse electrical... – For electronic systems and devices
Reexamination Certificate
2000-06-12
2001-11-06
Picard, Leo P. (Department: 2835)
Electricity: electrical systems and devices
Housing or mounting assemblies with diverse electrical...
For electronic systems and devices
C361S704000, C361S715000, C361S719000, C361S737000, C165S080200, C165S080300, C174S016300
Reexamination Certificate
active
06313995
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention:
The invention relates to a cooling system of a printed board on which a plurality of electronic devices are mounted.
2. Related Art:
As an integrated circuit (hereinafter referred to as IC) which is mounted on a printed board is becoming denser, a heating value of the IC, namely, the amount of heat generated in the IC increases. Accordingly, it is necessary to forcibly cool the IC.
An example of a conventional cooling system of a printed board is described with reference to FIG.
5
and FIG.
6
.
FIG. 5
is an exploded perspective view of a conventional cooling system of a printed board. In
FIG. 5
, the cooling system of a printed board comprises an electronic device
31
, a cylindrical thermal conduction body
32
, a spacer
33
, a coil spring
34
, a cooling block
35
, cooling pipes
36
, and screws
37
.
A thermal conductivity compound
39
a
is applied onto the upper surface of a package portion
31
a
of the electronic device
31
, and a thermal conductivity compound
39
b
is applied onto an insertion hole
35
a
provided in the cooling block
35
through which the thermal conduction body
32
is inserted at the portion where it contacts the thermal conduction body
32
. The cooling block
35
is fixed to a printed board
38
by way of the spacer
33
.
Screw holes
35
b
are provided on the upper surface of the cooling block
35
. Both ends of the coil spring
34
are attached to the cooling block
35
by two screws
37
. Owing to a tensile strength of the coil spring
34
, the bottom surface of the cylindrical thermal conduction body
32
is pressed against the upper portion of the package portion
31
a
of the electronic device
31
by way of the thermal conductivity compound
39
a.
FIG. 6
is a view for showing a state of mounting the conventional cooing system. In
FIG. 6
, the printed board
38
comprises a connector
41
, guard rails
42
, a fixed block
43
, closing type couplers
44
and a pulling plate
45
. The cooling pipes
36
through which a refrigerant
40
flows are fixed to the fixed block
43
which is fixed to the pulling plate
45
provided on the edge of the printed board
38
. When the refrigerant
40
is forced to flow through the cooling pipes
36
, the cooling block
35
around the cooling pipes
36
is cooled so that the electronic device
31
and printed board
38
are cooled by way of the cylindrical thermal conduction body
32
.
Since a plurality of electronic devices
31
are varied in height, a thermal conductivity gel or a contactor such as a spring or the like is needed for absorbing the variation in height between the bottom surface of the cylindrical thermal conduction body
32
and the upper surface of the package portion
31
a
of the electronic device
31
. However, as the heating density of the electronic device
31
increases, the thermal resistance of the thermal conductivity gel or the contactor such as a spring increases so that the reduction of variation in temperature generated in the electronic device
31
becomes difficult,.
Further, if failed electronic devices are produced on the printed board
38
on which the electronic devices are mounted, such failed electronic devices need to be inspected or replaced individually with other ones. Since the cooling part (cooling block shaft
35
) covers the upper surface of the electronic device
31
, when the electronic devices are inspected or replaced with other ones, the inspection has been difficult or an entire cooling part needed to be detached or removed for the replacement of the electronic devices. Accordingly, it take many steps for inspection, replacement or re-assembly.
Further, the conventional cooling system was high in packaged height and needed a heavy cooling block
35
.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a cooling system capable of securely cooling the electronic devices mounted on the printed board following or in accordance with heights of the electronic devices. Another object of the invention is to provide a cooling system that is thin and light in weight and facilitates the inspection and maintenance of the electronic devices mounted on the printed board.
To achieve the above object, a cooling system of a printed board according to a first aspect of the invention comprises a cooling member having a cooling path (e.g., a cooling pipe
1
) which is thermally connected onto a printed board
6
on which an electronic device (e.g. an electronic device
7
) is mounted as shown in
FIG. 1
, a thermal conduction member being thermally connected onto the electronic device, wherein the thermal conduction member
4
is inserted into an insertion hole formed in the cooling member so as to be thermally connected to the cooling member, thereby cooling the printed board and electronic device, characterized in that a plurality of thermal conduction members are provided in correspondence with a plurality of electronic devices.
A sectional area of each thermal conduction member is set to be greater than that of each electronic device. Further, each thermal conduction member can slide up and down in the insertion hole formed in the cooling member.
As mentioned above, according to the first aspect of the invention, since there are provided thermal conduction members in correspondence with respective electronic devices as the thermal conduction members to be inserted into the insertion holes of the cooling member on the printed board, the thermal conduction members can be disposed at the positions matching the heights of respective electronic devices, thereby dispensing with the interposition of contactors between the electronic devices and thermal conduction members so that respective electronic devices can be uniformly cooled.
A cooling system of a printed board according to a second aspect of the invention is characterized in further comprising, in the cooling system of the first aspect of the invention, a spring member (e.g. a leaf spring
5
) provided on the cooling member for pressing and biasing the thermal conduction members against the electronic devices, and a thermal conductivity elastic member by way of which the cooling members are fixed onto the printed board.
Here, a force to be pressed by the spring member is set to be a low load of not more than 1 Kg. For each thermal conductivity elastic member, gel excellent in thermal conductivity or a spring is used.
As mentioned above, according to the second aspect of the invention, each thermal conduction member can be pressed against and biased against each electronic device by the spring member so that the thermal conduction members can be forced to follow the heights of the electronic devices, and hence the thermal conduction members can be always thermally connected to the electronic devices. Further, since the pressing force of the spring member is set to be a low load, a stress applied to each electronic device can be set to the minimum.
Still further, since the cooling member is fixed onto the printed board by way of the thermal conductivity elastic member, the cooling member and printed board can be always thermally connected to each other.
A cooling system of a printed board according to a third aspect of the invention is characterized in that the cooling member of the first aspect of the invention comprises, for example, a frame-shaped cooling plate
2
fixed to the printed board and having a cooling path, and a thermal conduction plate
3
fixed to the cooling plate
2
and having insertion holes
9
as shown in FIG.
1
.
As mentioned above, according to the third aspect of the invention, since the cooling member is composed of the cooling plate and thermal conduction plate, the cooling system of a printed board can be rendered thin and light in weight. Further, since the cooling plate is frame-shaped, each electronic device can be replaced with another one by merely detaching the thermal conduction plate from the printed board.
A cooling system of a printed board according to a fourth aspect of the invention is characteriz
Koide Hiromichi
Suzuki Shinya
Tano Ichiro
Ando Electric Co. Ltd.
Datskovsky Michael
Flynn ,Thiel, Boutell & Tanis, P.C.
Picard Leo P.
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