Electricity: electrical systems and devices – Housing or mounting assemblies with diverse electrical... – For electronic systems and devices
Reexamination Certificate
1999-11-29
2001-09-04
Tolin, Gerald (Department: 2835)
Electricity: electrical systems and devices
Housing or mounting assemblies with diverse electrical...
For electronic systems and devices
C361S719000
Reexamination Certificate
active
06285546
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a mounting structure for an electronic device on which logical units and power supply units are to be mounted. More particularly, the invention relates to the mounting structure for an electronic device provided with such a power supply method and a unit layout as implementing the highly efficient power supply and cooling operation.
FIG. 7
shows an electronic device on which a multiple of printed boards are mounted according to the prior art. As shown in
FIG. 7
, for example, a host computer is configured so that logical units
22
and power supply units
23
are mounted on a frame
21
formed like a box. This type of computer includes a back board
25
one surface and the other surface of which normally have their corresponding units mounted thereon. In the configuration shown in
FIG. 7
, the logical units
22
are mounted on one surface of the back board
25
as being guided by the frame
21
and the guide rails
24
. Each logical unit
22
includes lots of semiconductor elements (LSI) and the other components mounted thereon. In the lower portion of the box is located an air fan unit for feeding cooling air to the logical units
22
and the power supply units
23
located in the upper portion thereof. This cooling air serves to cool down the logical units
22
and the power supply units
23
. The multiple of power supply units
23
operate to feed their respective powers. For example, as shown in
FIG. 8
, a power supply unit
23
a
feeds a power of 1.2 V, another power supply unit
23
c
feeds a power of 3.3 V, and another power supply unit
23
c
feeds a power of 5 V. In this case, the power supply unit
23
a
operates to feed a power of 1.2 V to the logical units
22
through a power supply bus bar
27
and the back board
25
.
However, the conventional mounting structure includes set of logical units mounted collectively on one surface of the back board
25
and a set of power supply units
23
mounted collectively on the other surface thereof. This structure involves the following disadvantages. That is, since the logical units
22
generally have a larger heat quantity than the power supply units
23
and they are mounted in the upper and the lower stages of the frame
21
, the higher heat value caused by the semiconductor elements included in the logical unit
22
is concentrated on one surface of the back board
25
(this side of FIG.
7
).
As described above, one power supply unit
23
a
operates to feed a power of 1.2 V to a plurality of logical units
22
through the power supply bus bar
27
composing a power supply path
27
a
. Hence, the power supply bus bar
27
through which the power supply unit
23
feeds a power is connected to the back board
25
in a branched manner. It means that the length of the power supply bus bar
27
is respective depending on the distance between the power supply unit
23
a
and each logical unit
22
. As a result, the shortest path and the longest path from the power supply unit
23
and the logical unit
22
may be provided. As the path is made longer, the drop of the voltage supplied from the power supply unit
23
a
is made larger. It has a problem of varying the voltage drop according to each path length.
Further, in the foregoing mounting structure, in a case that the two logical units
22
are mounted vertically in the upper and the lower stages, the guide rails
24
are located in the upper and the lower portions of the logical unit
22
. However, where the logical unit is mounted only in the lower stage, the guide rail
24
for guiding the logical unit
22
located in the upper stage is not required, so that no guide rail
24
is located on the top surface of the box. As shown in
FIG. 8
, the guide rail
24
is a tabular form having an opening in the center thereof for holding the logical unit
22
on which the semiconductor elements are mounted. The provision of the guide rail
214
serves to narrow the flow path of the cooling air, thereby resisting the flow of the cooling air. Hence, if the guide rail
24
exists in some place while it does not exist in another place, the presence or the absence of the guide rail
24
for resisting the flow of the cooling air results in bringing about the variation of the quantity of the cooling air for cooling the logical unit
22
.
Morever, as shown in
Fig. 9
, the foregoing mounting structure is constructed so that the logical unit
22
has plural LSIs
29
mounted thereon, the back board
25
has plural LSIs
28
as well, and the logical unit
22
is mounted on the back board
25
along the guide rail
30
. This mounting structure is cooled by the cooling air fed from the lower portion of FIG.
9
. However, the flow path of the cooling air for the LSIs
28
is not partitioned from the flow path of the cooling air whose temperature is raised by the heat of the LSIs
29
. This phenomenon makes the design of the cooling structure difficult.
SUMMARY OF THE INVENTION
As described above, the mounting structure for an electronic device according to the prior art is constructed so that the high heat is concentrated on one surface of the back board
25
. Further, the presence or the absence of the guide rail
24
results in bringing about the difference of the amount of the cooling air for cooling the logical units
22
. Moreover, the conventional mounting structure has a disadvantage that the heat of the LSIs
29
of the logical unit
22
give an adverse effect onto the LSIs
28
mounted on the back board. These disadvantages make the heat distribution inside of the box uneven and thereby the cooling efficiency lower.
Further, the mounting structure for an electronic device according to the prior art also has a disadvantage that a variety of lengths of the power supply paths between the power supply units
23
and the logical units
22
result in bringing about a variety of voltage drops, thereby making the supply voltage to each logical unit
22
uneven.
It is an object of the present invention to provide a mounting structure for an electronic device which is constructed to eliminate the disadvantages involved in the foregoing prior art and make the heat distribution inside of the box even, improve the cooling efficiency, and make the power voltage to each logical unit even.
Concretely, the object of the present invention is to provide a mounting structure for preventing concentration of heat appearing in the logical unit and the power supply unit and dispersing the heat, a mounting structure for increasing the flow passing through a unit in which a large amount of heat appears for dispersing the heat caused in each unit and making the heat even in the case of mounting the back board having the logical units and the power supply units mounted thereon vertically in the upper and the lower stages, a mounting structure for keeping the LSIs mounted on the back board from the influence of the rise of the air temperature caused by the heat of the logical units and the power supply units, a mounting structure for connecting the logical units to the corresponding power supply units for feeding an electric power t to the logical units by the shortest path, and a mounting structure for keeping a one-to-one correspondence between the logical unit and the corresponding power supply unit.
In order to achieve the foregoing object, according to an aspect of the invention, a mounting structure for an electronic device having plural logical units and plural power supply units for feeding a power to the logical units, both mounted on a back board, and an air fan unit for feeding cooling air to the logical units and the power supply units, has a first feature that the power supply units and the logical units are located alternately on each surface of the back board in a manner that the logical unit on one surface of the back board is opposed to the power supply unit on the other surface thereof and the power supply feeds an electric power to the logical unit closer thereto.
The present invention has a second feature that the distance betwe
Hayashi Yutaka
Kadomoto Eiji
Matsuo Kazuhiro
Miyamoto Mitsuo
Nakayama Koji
Antonelli Terry Stout & Kraus LLP
Hitachi , Ltd.
Tolin Gerald
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