Electronic apparatus and electronic equipment used therefor

Details Electronic apparatus and electronic equipment used therefor Electronic apparatus and electronic equipment used therefor

2001-12-11

2003-02-18

Chervinsky, Boris (Department: 2835)

Electricity: electrical systems and devices

Housing or mounting assemblies with diverse electrical...

For electronic systems and devices

C361S689000, C361S690000, C361S694000, C361S695000, C174S016100, C174S016300, C165S080300, C454S184000

Reexamination Certificate

active

06522541

ABSTRACT:

TECHNICAL FIELD
The invention relates to an electronic apparatus having a plurality of electronic equipments contained in a rack, which electronic equipments have electronic parts each making a heat source, and to an electronic equipment.
BACKGROUND ART
FIG. 8
is a plan view showing the construction of conventional electronic equipment. In
FIG. 8
, the reference numeral
1
denotes a rack,
2
electronic equipments,
3
a fan,
4
electronic parts constituting heat sources,
5
fins for radiating heat from the electronic parts
4
,
6
covers which cover the electronic parts
4
, and
17
is an electronic apparatus comprising these elements. Also,
FIG. 9
is a cross sectional view taken along the line A-A′ of the electronic equipment
2
. In
FIG. 9
, the reference numeral
7
denotes a chassis,
8
a package,
9
an inner casing,
10
fin-inbetween wind paths, and
11
a bypass wind path. In addition, in
FIG. 9
, the same reference numerals as those in
FIG. 8
denote the same or corresponding parts, and so an explanation thereof is omitted.
An explanation will be given below to the constitution. As shown in
FIG. 8
, a plurality of electronic equipments
2
are arranged in the rack
1
such that the fins
5
and covers
6
face each other. Provided between adjacent electronic equipments
2
is a clearance (gap), which facilitates mounting of the electronic equipments
2
and work for maintenance and replacement. Mounted on these electronic equipments
2
are electronic parts
4
, from which heat generates during action. The fins
5
extending from an upstream side, where an air inflows, to a downstream side are arranged in plural on a back surface of the chassis
7
, on which the electronic parts
4
are mounted. Conventionally, die casting is used to form the fins
5
integral with the chassis
7
. Die casting is a method of forming, in which a casting die is manufactured and a molten metal such as aluminum alloy or the like is injected into the casting die.
The fin-inbetween wind paths
10
(
FIG. 9
) are passages of an air flowing between adjacent fins
5
. And the bypass wind path
11
is a passage of an air not flowing into the fin-inbetween wind paths
10
. The bypass wind path
11
means a clearance between adjacent electronic equipments
2
, that is, a passage of an air flowing between the fins
5
and the cover
6
of predetermined electronic equipments
2
, and also means a passage of an air flowing between the fins
5
and inner walls of the rack
1
. The rack
1
is provided with the fan
3
, which supplies an air to an interior of the rack
1
. In addition, the fins
5
and the chassis
7
, which have been integrally formed, in combination is called a heat sink.
An explanation will be given below to the action. The electronic parts
4
mounted in the respective electronic equipments
2
generate heat during action. The electronic parts
4
reach a temperature of about 100° C., and 140° C. or higher when high. Heat generated from the electronic parts
4
is transmitted to the package
8
, inner casing
9
, chassis
7
, and the fins
5
shown in FIG.
9
. Meanwhile, the fan
3
supplies an air to the interior of the rack
1
to create flows of wind passing through the fin-inbetween wind paths
10
and the bypass wind path
11
. Heat transmitted to the fins
5
, of heat generated from the electronic parts
4
is finally dispersed by wind flowing through the fin-inbetween wind paths
10
. In this manner, since heat generated from the electronic parts
4
is mainly dispersed by wind flowing through the fin-inbetween wind paths
10
, working of heat in the electronic parts
4
is suppressed.
With the electronic apparatus described above, the plurality of electronic equipments
2
are contained in the rack
1
with predetermined gaps between adjacent electronic equipments
2
, as the result of taking account of workability in mounting, maintenance and replacement. In such electronic apparatus, a part of an air supplied from the fan
3
flows into the bypass wind path
11
and the remainder of the air flows into the fin-inbetween wind paths
10
. In order to enhance the heat radiation efficiency of the electronic equipments
2
, it is sufficient to increase an amount of an air flowing into the fin-inbetween wind paths
10
and to decrease an amount of an air flowing into the bypass wind path
11
.
FIG. 10
is a graph showing a ratio of air volumes flowing through fin-inbetween wind paths and a bypass wind path, and an illustration thereof. As shown in
FIG. 10A
, a bypass air volume (B) flowing into the bypass wind path
11
amounts to 35% of a total air volume, which is a total amount of an air supplied by the fan
3
.
FIG. 10B
shows a manner, in which an air flows into the fin-inbetween wind paths and the bypass wind path. A ratio of a fin-inbetween air volume and a bypass air volume in the total air volume is determined by balancing of wind-path resistances in the fin-inbetween wind paths and the bypass wind path.
Hereupon, in the case where four electronic equipments
2
are mounted within the rack
1
as in the electronic apparatus shown in
FIG. 8
, four sets of the fin-inbetween wind paths and the bypass wind path are naturally defined. The fin-inbetween wind paths and the bypass wind path are described below as “wind paths”. It has been revealed that an air taken into the rack
1
by the fan
3
does not flow evenly into the four wind paths but air volumes flowing into the respective wind paths scatter 20% at the maximum. Since air volumes flowing into the respective wind paths are uneven, the respective electronic equipments
2
scatter in heat radiation efficiency. That is, there is possibly caused the situation that among the electronic equipments mounted within the rack
1
, those electronic equipments, for which a large amount of air flows into the wind paths, efficiently radiate heat but those electronic equipments, for which a small amount of air flows into the wind paths, do not act normally due to overheat. The reason why air volumes flowing into the respective wind paths scatter is believed to be due to scatter in wind-path resistance (pressure loss) for the respective wind paths, wind speed distribution within the rack
1
, positions where the electronic equipments
2
are mounted, and the like.
In order to permit the respective electronic equipments
2
within the rack
1
to evenly radiate heat, it is necessary to suppress scatter in air volumes flowing into the four wind paths. In order to suppress scatter in air volumes flowing into the respective wind paths, measures have been conventionally adopted, in which a spacing between adjacent fins
5
, that is, fin pitch is modified to adjust pressure loss (wind-path resistance) in fin-inbetween wind paths. When pressure loss is adjusted by modification of fin pitch, however, there is caused a problem that the electronic equipments
2
are lowered in heat radiation efficiency since balancing of pressure loss between the fin-inbetween wind paths and the bypass wind path is lost to permit an air flowing into the fin-inbetween wind paths to pass through the bypass wind path. Also, it is difficult to manufacture a heat sink of small fin pitch with the use of die casting. The reason for this is that resistance encountered when a molten metal is poured into tip ends of a casting die increases as the fin pitch becomes narrow and so high pressures must be applied when a molten metal is poured into the casting die. Also, since an area, at which the molten metal contacts with inner surfaces of the casting die, increases, the molten metal frequently solidifies before it reaches tip ends of the casting die, and so it is difficult to obtain a fin configuration in accordance with a design.
BRIEF SUMMARY OF THE INVENTION
The invention has been accomplished to solve the above-mentioned problems and has its object to eliminate scatter in air volumes flowing into a plurality of wind paths formed between a plurality of electronic equipments contained in a rack of an electronic apparatus.
An electronic apparat

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