U.S. patent application number 13/587425 was filed with the patent office on 2013-02-28 for fan modules and server equipment.
This patent application is currently assigned to HITACHI, LTD.. The applicant listed for this patent is Akira GOTO, Taku IWASE, Shigeyasu TSUBAKI, Yusuke UCHIYAMA. Invention is credited to Akira GOTO, Taku IWASE, Shigeyasu TSUBAKI, Yusuke UCHIYAMA.
Application Number | 20130051997 13/587425 |
Document ID | / |
Family ID | 46754885 |
Filed Date | 2013-02-28 |
United States Patent
Application |
20130051997 |
Kind Code |
A1 |
UCHIYAMA; Yusuke ; et
al. |
February 28, 2013 |
FAN MODULES AND SERVER EQUIPMENT
Abstract
A fan module and server equipment are provided that can achieve
a balance between increased airflow and noise reduction when an
axial flow fan is mounted in the server equipment. The fan module
for taking in and discharging air includes a stator located on an
upstream side with respect to airflow and an axial flow fan located
on the downstream side. When the fan module is viewed from the
rotational-axial direction of the axial flow fan, if a leading edge
of a rotor vane constituting part of the axial flow fan passes a
trailing edge of a stator vane constituting part of the rotor, a
skew is formed in which the leading edge of the rotor vane
constantly intersects the leading edge of the rotor vane at a
single point.
Inventors: |
UCHIYAMA; Yusuke;
(Hitachinaka, JP) ; IWASE; Taku; (Mito, JP)
; TSUBAKI; Shigeyasu; (Odawara, JP) ; GOTO;
Akira; (Isehara, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
UCHIYAMA; Yusuke
IWASE; Taku
TSUBAKI; Shigeyasu
GOTO; Akira |
Hitachinaka
Mito
Odawara
Isehara |
|
JP
JP
JP
JP |
|
|
Assignee: |
HITACHI, LTD.
Tokyo
JP
|
Family ID: |
46754885 |
Appl. No.: |
13/587425 |
Filed: |
August 16, 2012 |
Current U.S.
Class: |
415/193 ;
415/191 |
Current CPC
Class: |
F04D 29/384 20130101;
F04D 29/541 20130101; F04D 19/007 20130101; F04D 29/665
20130101 |
Class at
Publication: |
415/193 ;
415/191 |
International
Class: |
F04D 29/54 20060101
F04D029/54 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 29, 2011 |
JP |
2011-185443 |
Claims
1. A fan module for taking in and discharging air, comprising: a
stator located on an upstream side with respect to airflow; and an
axial flow fan located on a downstream side with respect to the
airflow; wherein, when the fan module is viewed from a
rotational-axial direction of the axial flow fan, the stator
includes a stator vane trailing edge and the axial flow fan
includes a rotor vane leading edge, the trailing edge and the
leading edge each having two points of intersection with two
concentric circles having different diameters, and wherein a
straight line connecting the two points of intersection on the
trailing edge and a straight line connecting the two points of
intersection on the leading edge are configured such that if, on
one of the two concentric circles, one point of intersection on the
trailing edge is superimposed on the point of intersection on the
leading edge, on the other of the two concentric circles, the other
point of intersection on the trailing edge is not coincident with
the other point of intersection on the leading edge.
2. The fan module according to claim 1, wherein the rotor vane has
a tilt direction opposite to that of the stator vane.
3. The fan module according to claim 1, wherein the stator vane
constituting part of the stator is configured to be warped like a
U-shape.
4. The fan module according to claim 3, wherein the stator vane
applies a reverse pre-swirl to the rotor vane.
5. The fan module according to claim 1, wherein a second stator is
disposed on the downstream side of the axial flow fan.
6. The fan module according to claim 5, wherein a trailing edge of
a stator vane constituting part of the second stator disposed on
the downstream side of the axial flow fan is located at a positive
position with respect to a position of a leading edge of the stator
vane in a rotational direction of the axial flow fan.
7. The fan module according to claim 1, wherein an interval between
adjacent stator vanes constituting part of the stator is smaller
than a width of a finger.
8. The fan module according to claim 1, wherein the axial flow fan
and the stator constituting the fan module are integrated with each
other.
9. The fan module according to claim 1, wherein a plurality of the
fan modules are combined in series or in parallel.
10. Server equipment in which the fan module according to claim 1
is mounted.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates generally to fan modules and
server equipment. The invention more particularly relates to a fan
module formed by combining an axial flow fan with a stator, and
server equipment which is an information instrument in which the
fan module is mounted.
[0003] 2. Description of the Related Art
[0004] Office automation equipment, IT devices and home electric
appliances include therein a cooling fan for cooling electronic
components from which heat is emitted. In recent years, these home
electric appliances, office automation equipment and home electric
appliances have increasingly been downsized and sophisticated in
the market. Electronic components in the internal structure of the
equipment or the like are increased in density along with the
downsizing and sophistication. Thus, the amount of heat generation
across the electronic components tends to increase.
[0005] To address the increase in the heat generation across the
electronic components, an axial flow fan that is small-sized and
can easily provide airflow is generally employed as a cooling fan.
In many cases, designers use general-purpose axial flow fans
available from fan's vendors to implement such small-sized axial
flow fans in the equipment in a manner suitable for their
respective applications.
[0006] Naturally, each of the general-purpose small-sized axial
flow fans is not adjusted to match a corresponding one of devices.
Therefore, many devices cannot bring out desired performance from
the axial flow fans.
[0007] In particular, when boards and the like are mounted in high
density in a device such as information instruments represented by
server equipment used in a data center, airflow entering the axial
flow fan is made turbulent and flow passages for such airflow are
reduced in width. Thus, an amount of airflow generated by the axial
flow fan is significantly lowered and noise is increased.
[0008] Accordingly, general-purpose small-sized axial flow fans to
be mounted in information instruments emphasize technologies for
enabling increased airflow and reduced noise.
[0009] For example, WO2008/062835 describes the following. A first
axial flow fan and a second axial flow fan, i.e., two axial flow
fans in total, are arranged in series in the order from the
upstream side of airflow with respect to a rotational-axial
direction of the fan. A flow straightener is disposed between the
first and second axial flow fans. The flow straightener changes the
direction of airflow coming out from the first axial flow fan,
thereby applying a swirl flow in a direction reverse to the
rotational direction of the second axial flow fan to the second
axial flow fan. There is an effect of improving the static pressure
characteristics of the two axial flow fans to increase the amount
of airflow.
SUMMARY OF THE INVENTION
[0010] The conventional technology as mentioned above produces the
effect of improving the amount of airflow; however, it does not
refer to noise reduction. Therefore, there is the necessity of
achieving a balance between the increase in airflow and the noise
reduction when the axial flow fans are mounted. In addition, since
the conventional technology premises the series configuration of
the two axial flow fans, there is a problem in that the
conventional technology cannot be applied to information
instruments that do not meet such a premise.
[0011] It is an object of the present invention to provide a fan
module and server equipment that achieve increased airflow and
reduced noise of an axial flow fan to be mounted on an information
instrument or the like.
[0012] According to an aspect of the present invention, there is
provided a fan module for taking in and discharging air, including:
a stator located on an upstream side with respect to airflow; and
an axial flow fan located on a downstream side with respect to the
airflow. When the fan module is viewed from a rotational-axial
direction of the axial flow fan, the stator includes a stator vane
trailing edge and the axial flow fan includes a rotor vane leading
edge, the trailing edge and the leading edge each having two points
of intersection with two concentric circles having different
diameters. A straight line connecting the two points of
intersection on the trailing edge and a straight line connecting
the two points of intersection on the leading edge are configured
such that if, on one of the two concentric circles, one point of
intersection on the trailing edge is superimposed on the point of
intersection on the leading edge, on the other of the two
concentric circles, the other point of intersection on the trailing
edge is not coincident with the other point of intersection on the
leading edge.
[0013] Preferably, the rotor vane has a tilt direction opposite to
that of the stator vane.
[0014] Preferably, the stator vane applies a reverse pre-swirl to
the rotor vane.
[0015] Preferably, the stator vane constituting part of the stator
is configured to be warped like a U-shape.
[0016] Preferably, a second stator is disposed on the downstream
side of the axial flow fan.
[0017] Preferably, a trailing edge of a stator vane constituting
part of the second stator disposed on the downstream side of the
axial flow fan is located at a positive position with respect to a
position of a leading edge of the stator vane in a rotational
direction of the axial flow fan.
[0018] Preferably, an interval between adjacent stator vanes
constituting part of the stator is smaller than a width of a
finger.
[0019] Preferably, the axial flow fan and the stator constituting
the fan module are integrated with each other.
[0020] Preferably, a plurality of the fan modules are combined in
series or in parallel.
[0021] According to another aspect of the present invention, there
is provided server equipment in which the fan module described
above is mounted.
[0022] The present invention can provide a fan module that can
achieve a balance between increased airflow and noise reduction in
an axial flow fan mounted in server equipment.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] FIG. 1 is a perspective view of a fan module according to a
first embodiment of the present invention.
[0024] FIG. 2 is a perspective view of a stator constituting part
of the fan module shown in FIG. 1.
[0025] FIG. 3 is a perspective view of an axial flow fan
constituting part of the fan module shown in FIG. 1.
[0026] FIG. 4 is an explanatory view showing a state of airflow
entering the axial flow fan exposed to the atmosphere.
[0027] FIG. 5 is an explanatory view showing a state of airflow
entering the axial flow fan mounted in an information
instrument.
[0028] FIG. 6 is a graph showing a comparison of velocity
distribution of airflow entering the axial flow fan between when
the axial flow fan is exposed to the atmosphere and when it is
mounted in the information instrument.
[0029] FIG. 7 is a diagram partially showing the fan module shown
in FIG. 1 as viewed from a direction of a rotational axis.
[0030] FIG. 8 is a graph showing an effect of a second embodiment
of the present invention.
[0031] FIG. 9 is a schematic cross-sectional view of a fan module
according to a third embodiment of the present invention.
[0032] FIG. 10 is a perspective view of a fan module according to a
fourth embodiment of the present invention.
[0033] FIG. 11 is a perspective view of a stator constituting part
of the fan module shown in FIG. 10.
[0034] FIG. 12 is a schematic cross-sectional view of the fan
module according to the fourth embodiment of the present
invention.
[0035] FIG. 13 is a perspective view of a fan module according to a
fifth embodiment of the present invention.
[0036] FIG. 14 is a perspective view of a stator constituting part
of the fan module shown in FIG. 13.
[0037] FIG. 15 is a configurational schematic of a PC server
according to a sixth embodiment of the present invention.
[0038] FIG. 16 is a perspective view of a fan module according to a
seventh embodiment of the present invention.
[0039] FIG. 17 is a graph showing an effect of the seventh
embodiment of the present invention.
[0040] FIG. 18 is a perspective view of a fan module according to
an eighth embodiment of the present invention.
[0041] FIG. 19 is a perspective view of a fan module according to a
ninth embodiment of the present invention.
[0042] FIG. 20 is a configurational schematic of a blade server
according to a tenth embodiment of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0043] Preferred embodiments of the present embodiment will
hereinafter be described with reference to the drawings. A
schematic configuration of a fan module is first described with
reference to FIGS. 1 to 3. Members denoted with the same reference
numerals in the figures have the same function; therefore, their
explanations may be omitted in other figures. FIG. 1 is a
perspective view of a fan module. The fan module 1 is configured
such that a stator 2 and an axial flow fan 3 are arranged in series
in this order from the upstream side of airflow.
[0044] FIG. 2 is a perspective view of the axial flow fan 2. The
axial flow fan 2 includes a boss 21, stator vanes 22 extending from
the boss 21, and an outer frame 23 supporting the stator vanes.
[0045] FIG. 3 is a perspective view of the axial flow fan. The
axial flow fan 3 includes a rotating boss 31 to which a motor is
mounted; rotor vanes 32 extending from the boss 31; a motor cup 33
supporting the motor mounted to the boss; braces 34 supporting the
motor cup 33; and an outer frame 35 supporting the braces 34.
First Embodiment
[0046] A first embodiment is described with reference to FIGS. 4, 5
and 6. FIG. 4 is an explanatory view showing a state of airflow
entering the axial flow fan exposed to the atmosphere. FIG. 5 is an
explanatory view showing a state of airflow entering the axial flow
fan mounted in an information instrument. FIG. 6 is a graph showing
a comparison in velocity distribution of airflow entering the axial
flow fan between when the axial flow fan is exposed to the
atmosphere and when it is mounted in the information
instrument.
[0047] In cooling a variety of information instruments, resistor
bodies such as boards which disturb airflow are generally located
on the upstream side of a cooling fan. If the airflow thus
disturbed by these resistor bodies enters the cooling fan mounted
in an information instrument, noises are generated. As shown in
FIG. 4, general-purpose small-sized axial flow fans are presupposed
to be used under atmosphere-exposure conditions; therefore, they
are designed under the assumption that airflow a1 enters the axial
flow fan not only from a rotational-axial direction but from a
direction perpendicular to the rotational-axial direction. On the
other hand, the axial flow fan mounted in the information
instrument has a restricted flow passage; therefore, airflow a2
enters the axial flow fan only from the rotational-axial direction
as shown in e.g. FIG. 5. If distributions in airflow velocity in
the rotational-axial direction are compared between the conditions
of airflow into the axial flow fan as described above, the results
are as shown in FIG. 6. In FIG. 6, an intersection between a
vertical axis and a transverse axis corresponds to the position of
radius 0 of the axial flow fan (i.e., the position of the center of
the axial flow fan). As seen from FIG. 6, in the case of the axial
flow fan mounted in the information instrument (the solid line in
FIG. 6), the velocity of airflow in a rotational-axial direction is
averagely increased because of the restricted flow passage. In
other words, the average value of the velocity distribution of
airflow entering the axial flow fan mounted in the information
instrument is greater than that of the airflow entering the axial
flow fan exposed to the atmosphere.
[0048] The axial flow fan mounted in the information instrument is
used under the conditions different from originally assumed
conditions. Therefore, an amount of airflow and static pressure are
reduced.
[0049] If the fan module 1 shown in FIG. 1 is used to cool a
variety of information instruments similarly to the conventionally
used axial flow fan, airflow disturbed by the resistor bodies
(specific examples are described later but they mean objects to be
cooled in e.g. server equipment) located on the upstream side of
the fan module is straightened by the stator 2. Thereafter, the
airflow thus straightened enters the axial flow fan 3. In this way,
disturbed airflow does not enter the axial flow fan 3. Thus,
possible noise can be suppressed. Even in the state where the axial
flow fan is mounted in the information instrument, the axial flow
fan is improved to meet the inflow conditions assumed when
designing the axial flow fan. Thus, the amount of airflow and
static pressure of the axial flow fan mounted in the information
instrument are increased compared with an axial flow fan not
provided with a stator on the upstream side thereof.
Second Embodiment
[0050] As shown in FIG. 1, the fan module 1 has the stator 2
disposed immediately in front of the axial flow fan 3. The rotor
vanes 32 are rotated along with the rotation of the boss 31 to
which the motor of the axial flow fan 3 is attached. The rotation
of the rotor vanes 32 causes interference with the stator vanes 22
of the stator. Thus, there is concern about increased noise of
frequencies resulting from the number of the rotor vanes 32 or of
the stator vanes 22.
[0051] To address the concern noise, a second embodiment focuses on
a positional relationship between the stator vanes 22 and the rotor
vanes 32. This suppresses increase in the noise of frequencies
resulting from the number of the rotor vanes 32 or the stator vanes
22.
[0052] FIG. 7 partially shows the fan module 1 as viewed from the
upstream side of airflow in the rotational-axial direction of the
rotor vanes 32. As described earlier, the interference between the
rotor vanes 32 and the stator vanes 22 occurs when the rotor vane
32 rotating in the direction of an arrow in FIG. 7 passes the
stator vane 22 at rest.
[0053] In FIG. 7, circles 41, 42 have different radii and are
concentric with the boss 21 of the stator 2. A point of
intersection between the circle 41 and the stator vane 22 is
assumed as a point 43. A point of intersection between the circle
42 and the stator vane 22 is assumed as a point 44. A point of
intersection between the circle 41 and the rotor vane 32 is assumed
as a point 45. A point of intersection between the circle 42 and
the rotor vane 32 is assumed as a point 46. A line segment
connecting the point 43 with the point 44 is assumed as a line 47,
and a line segment connecting the point 45 with the point 46 is
assume as a line 48. The fan module in the second embodiment is
configured such that if the point 43 and the point 45 are
superimposed on each other on the circle 41 or the point 44 and the
point 46 are superimposed on each other on the circle 42, the line
47 is not coincident with the line 48. This non-coincident
configuration means a state where as shown in e.g. FIG. 7, if the
point 46 on the rotor vane 32 shifts to a position superimposed on
the point 44 on the stator vane, another point 45' on the rotor
vane 32 is not superimposed on the point 43 on the stator vane.
[0054] More specifically, the fan module taking in and discharging
air is characteristically configured as below. The fan module
includes the stator located on the upstream side with respect to
airflow and the axial flow fan located on the downstream side. When
the fan module is viewed from the rotational-axial direction of the
axial flow fan, if two virtual concentric circles having different
radii are assumed, a trailing edge of a stator vane constituting
part of the stator and a leading edge of a rotor vane constituting
part of the axial flow fan each have two points of intersections
with the two concentric circles. A straight line connecting the two
points of intersection on the trailing edge of the stator vane and
a straight line connecting the two points of intersection on the
leading edge of the rotor vane are configured as below. If, on one
of the two concentric circles, one point of intersection on the
trailing edge of the stator vane is superimposed on the point of
intersection on the leading edge of the rotor vane, on the other of
the two concentric circles, the other point of intersection on the
trailing edge of the stator vane is not coincident with the other
point of intersection on the leading edge of the rotor vane.
[0055] Further, when the leading edge of the rotor vane passes the
trailing edge of the stator vane, a skew is formed in which the
leading edge of the rotor vane constantly intersects the leading
edge of the rotor vane at a single point.
[0056] With this configuration, the rotor vane 32 constantly passes
the stator vane 22 only at a single point. Therefore, an area where
the interference between the rotor vane and the stator vane occurs
simultaneously can be minimized. This can produce an effect of
suppressing an increase in the sound pressure level of each
frequency component of noises resulting from the number of the
rotor vanes 32 or the stator vanes 22. FIG. 8 is a graph showing
the effect of the second embodiment. FIG. 8 can confirm the fact
that the fan module of the second embodiment shown in FIG. 7 can
reduce the noise of vane passing frequency (the sound pressure
level) resulting from the number of the rotor vanes or the stator
vanes. If the second embodiment is implemented, the sound pressure
level is lowered as a whole compared with the case that the second
embodiment is not implemented. Incidentally, if "order of vane
passing frequency" of the horizontal axis in FIG. 8 is n-order, a
relationship is such that "noise frequency"/("the rotation number
of the axial flow fan".times."the number of vanes")=n.
Third Embodiment
[0057] In a third embodiment, a configuration in which the
direction of airflow is changed by stator vanes is added to that of
the first or second embodiment to thereby increase the amount of
airflow in a fan module mounted in server equipment such as an
information instrument. FIG. 9 is a schematic cross-sectional view
of a fan module of the third embodiment, showing a positional
relationship between a stator vane 22 and a rotor vane 32. The
stator vane 22 of a stator and the rotor vane 32 of an axial flow
fan are arranged from the upstream side of airflow. The rotor vane
32 is rotated in a rotational direction R. The stator vane 22 is
warped in a U-shape in cross-section relative to the rotational
direction R.
[0058] A velocity component 51 of airflow entering the fan module
is changed in direction by the stator vane 22 and turned to a
velocity component 52 of the airflow, which enters the rotor vane
32. In other words, because of the presence of the stator vane 22,
the airflow having a velocity component 54 which is a
circumferential velocity in a direction reverse to the rotational
direction R enters the rotor vane 32. In short, the stator vane
applies a reverse pre-swirl to the rotor vane. In general, an axial
flow fan is designed under the assumption that the airflow entering
the rotor vane has no circumferential velocity component. However,
if the axial flow fan is mounted in a variety of information
instruments or the like for use, airflow is disturbed; therefore,
the airflow having a circumferential velocity component which has
the same direction as the rotational direction of the axial flow
fan enters the axial flow fan. Incidentally, a velocity component
53 of the airflow has the same direction and magnitude as those of
the velocity component 51 of airflow entering the fan module.
[Expression 1]
P.sub.th=.rho.(C.sub.u2u.sub.2-C.sub.u1u.sub.1) expression 1
[0059] P.sub.th: Theoretical total pressure
[0060] .rho.: Density
[0061] C.sub.u1: Swirl velocity at rotor vane inlet
[0062] C.sub.u2: Swirl velocity at rotor vane outlet
[0063] u.sub.1: Circumferential velocity at rotor vane inlet
[0064] u.sub.2: Circumferential velocity at rotor vane outlet
[0065] Expression 1 is an expression representing the theoretical
total pressure of the axial flow fan. According to this expression,
the theoretical total pressure of the axial flow fan is obtained by
multiplying a value by the air density .rho., such a value being
obtained by reducing the product of the swirl velocity C.sub.u1
which is the circumferential velocity component at the axial flow
fan inlet and the rotating velocity u.sub.1 from the product of the
swirl velocity C.sub.u2 which is the circumferential velocity
component at the axial flow fan outlet and the rotating velocity
u.sub.2. This expression shows that if the airflow entering the
axial flow fan has a circumferential velocity component in the same
direction as the rotational direction of the axial flow fan, the
total pressure of the axial flow fan is lowered. On the other hand,
the stator vane 22 of the third embodiment allows the airflow
having the circumferential velocity component in a direction
reverse to the rotational direction R of the rotor vane 32 to enter
the rotor vane 32. According to expression 1, such airflow
increases the theoretical total pressure of the axial flow fan,
which leads to increased static pressure and also to the increased
amount of airflow.
Fourth Embodiment
[0066] FIG. 10 is a perspective view of a fan module 11 according
to a fourth embodiment. The fan module 11 is configured such that a
first stator 2, an axial flow fan 3 and a second stator 6 are
arranged in this order from the upstream side of airflow. The first
stator 2 and the axial flow fan 3 are the same as those in the
first to third embodiments.
[0067] FIG. 11 is a perspective view of a configuration of the
second stator 6. The second stator 6 includes a boss 61, a
plurality of stator vanes 62 extending from the boss 61, and an
outer frame 63 supporting the stator vanes 62.
[0068] FIG. 12 is a schematic cross-sectional view of the fan
module, showing a positional relationship among the stator vane 22,
the rotor vane 32 and the stator vane 62 according to the fourth
embodiment. The stator vane 22 of the first stator, the rotor vane
32 of the axial flow fan and the stator vane 62 of the second
stator are arranged from the upstream side of airflow. The rotor
vane 32 is rotated in a rotational direction R. The stator vane 62
has a trailing edge located at a positive position with respect to
the position of the leading edge in the rotational direction R.
Incidentally, the airflow entering the stator vane 22 and reaching
the rotor vane 32 is the same as that in FIG. 9. Further, the
airflow coming out from the rotor vane 32 enters the stator vane 62
at a velocity component 55. The airflow having passed the stator
vane 62 is straightened and runs out at a velocity component
56.
[Expression 2]
P.sub.s=.rho..eta..sub.s.times.(V.sub.2.sup.2-V.sub.3.sup.2)/2
expression 2
[0069] P.sub.s: Static pressure rise
[0070] .rho.: Density
[0071] .eta..sub.s: Static pressure efficiency
[0072] V.sub.2: Absolute value of velocity at stator vane inlet
[0073] V.sub.3: Absolute value of velocity at stator vane
outlet
[0074] Expression 2 is an expression representing a static pressure
rise due to the second stator. According to this expression, the
static pressure rise due to the second stator is obtained by
multiplying a value by the density .rho. of air and static pressure
efficiency .eta..sub.s, such a value being obtained by subtracting
the square of an absolute value V.sub.3 of the velocity at the
stator vane outlet from the square of an absolute value V.sub.2 of
the velocity at the stator vane inlet. If the effect of the second
stator is correlated with FIG. 12, the velocity component 55 is
reduced by the stator vane 62 and changed into velocity 56. That is
to say, the static pressure is raised according to the reduced
velocity to increase the amount of airflow.
Fifth Embodiment
[0075] FIG. 13 is a perspective view of a fan module 12 according
to a fifth embodiment. The fan module 12 is configured such that a
stator 7 and an axial flow fan 3 are arranged in series in this
order from the upstream side of airflow.
[0076] FIG. 14 is a perspective view of a detailed configuration of
the stator 7 in FIG. 13. The stator 7 includes a boss 71, a
plurality of stator vanes 72 extending from the boss 71, one or
more guide rings 73, and an outer frame 74 supporting the stator
vanes. The number of the stator vanes 72 is set so that the
interval between the stator vanes 72 adjacent to each other may be
smaller than the size of a finger of an operator handling server
equipment. The guide ring or guide rings are further installed to
completely prevent the entering of the operator's finger.
[0077] The fan module 12 has an effect of completely preventing the
operator's finger from entering the stator 7. That is to say,
safety measures are taken for fan module replacing work.
[0078] Incidentally, the fifth embodiment does not always need the
guide ring 73. If the interval between the stator vanes 72 adjacent
to each other is smaller than the size of the operator's finger,
the same effect as that of the guide ring can be produced.
Sixth Embodiment
[0079] FIG. 15 is a configurational schematic of a PC server in
which fan modules are mounted according to a sixth embodiment. The
PC server 8, which is a type of server equipment, includes a
chassis 81, units 82 each having an inside board on which a CPU is
mounted, and fan modules 13.
[0080] The fan module described in any one of the first to fifth
embodiment can be used as the fan module 13. The fan module 13 is
of an integral structure in which a stator and an axial flow fan
are joined to each other. Therefore, time required for mounting
work and replacing work for the fan module 13 can be reduced.
Seventh Embodiment
[0081] FIG. 16 is a perspective view of a fan module according to a
seventh embodiment. A fan module 111 is configured such that a
first fan module 14 and a second fan module 15 are arranged in
series. The fan module described in any one of the first to sixth
embodiments can be used as the first and second fan modules 14,
15.
[0082] Among information instruments, particularly an information
instrument having a high-density inside structure is increased in
pressure loss. Such an information instrument uses two or more
axial flow fans arranged in series in order to provide an amount of
cooling air needed for a statistic pressure rise. The use of the
axial flow fans arranged in series expects to increase the static
pressure according to the increased number of the axial flow fans.
However, such an expected effect is not generally obtained. For
example, if two axial flow fans arranged in series are used, a
double static pressure rise is expected. However, only an
approximate one-and-a-half static pressure rise can be obtained in
actuality.
[0083] As in the seventh embodiment, if the fan modules described
in any one of the first to sixth embodiments are arranged in series
for use, the single axial flow fan is fan-modularized to increase
static pressure and also airflow is straightened. Thus, as shown in
FIG. 17, a static pressure rise two times or more of that in the
case where the single axial flow fans are arranged in series can be
obtained.
[0084] Incidentally, the fan module 111 described in the seventh
embodiment is configured such that the two fan modules are arranged
in series. However, the effect of the seventh embodiment can be
produced without limiting the number of the fan modules arranged in
series. Additionally, it is not always necessary to use the same
fan modules arranged in series.
Eighth Embodiment
[0085] FIG. 18 is a perspective view of a fan module according to
an eighth embodiment. A fan module 112 is configured such that a
first axial flow fan 3, a first stator 6, a second stator 2 and a
second axial flow fan 3 are arranged in series in this order from
the upstream side of airflow.
[0086] When the fan module is viewed from the rotational-axial
direction of the second axial flow fan, if two virtual concentric
circles having different radii are assumed, a trailing edge of a
stator vane constituting part of the second stator and a leading
edge of a rotor vane constituting part of the second axial flow fan
each have two points of intersection with the two concentric
circles. A straight line connecting the two points of intersection
on the trailing edge of the stator vane and a straight line
connecting the two points of intersection on the leading edge of
the rotor vane are configured as below. If, on one of the two
concentric circles, one point of intersection on the trailing edge
of the stator vane is superimposed on the point of intersection on
the leading edge of the rotor vane, on the other of the two
concentric circles, the other point of intersection on the trailing
edge of the stator vane is not coincident with the other point of
intersection on the leading edge of the rotor vane.
[0087] Further, the second axial flow fan has the rotor vanes and
the second stator has the stator vanes. It is preferred that the
tilt direction of the rotor vane be opposite to that of the stator
vane.
[0088] As with the seventh embodiment, the fan module 112 provides
a static pressure rise greater than that in the case where the
axial flow fan units are arranged in series for use. In particular,
if a dimensional limitation is put on the fan module and the
configuration of the seventh embodiment cannot be employed, the
present embodiment produces an effect.
Ninth Embodiment
[0089] FIG. 19 is perspective view of a fan module according to a
ninth embodiment. A fan module 113 is configured such that a first
fan module 16 and a second fan module 17 are juxtaposed to each
other.
[0090] To increase the amount of airflow of, particularly, an
information instrument having a low-density inside structure among
information instruments, axial flow fans are juxtaposed to each
other for use to increase the amount of cooling airflow. The use of
the fan modules juxtaposed to each other as in the present
embodiment can increase the amount of airflow for cooling the axial
flow fans juxtaposed to each other and mounted in an information
instrument.
[0091] Incidentally, the fan module 113 described in the ninth
embodiment is a fan module in which the two fan modules described
in any one of the first to eighth embodiments are juxtaposed to
each other. However, the fan modules of the present embodiment can
produce the effect without limiting the number of the fan modules
juxtaposed to one another and without the necessity of using the
same fan modules.
Tenth Embodiment
[0092] FIG. 20 is a configurational schematic of a blade server,
which is an example of server equipment, according to a tenth
embodiment. A blade server 9 includes a casing 91, an electronic
device section 92 including server blades, and a fan module
1111.
[0093] For example, the fan module 1111 is configured to combine a
plurality of the fan modules described in any one of the first to
ninth embodiments. Therefore, the fan module 1111 produces an
effect of increasing the amount of airflow generated by the blade
server 9 and of reducing noise thereof.
[0094] The application of the fan module in the present embodiment
is not limited to the blade server but can be applied to general
server equipment such as rack servers and PC servers.
[0095] It is to be noted that the present invention is not limited
to the aforementioned embodiments, but covers various
modifications. While, for illustrative purposes, those embodiments
have been described specifically, the present invention is not
necessarily limited to the specific forms disclosed. Thus, partial
replacement is possible between the components of a certain
embodiment and the components of another. Likewise, certain
components can be added to or removed from the embodiments
disclosed.
[0096] Note also that some or all of the aforementioned components,
functions, processors, and the like can be implemented by hardware
such as an integrated circuit or the like. Alternatively, those
components, functions, and the like can be implemented by software
as well. In the latter case, a processor can interpret and execute
the programs designed to serve those functions. The programs,
associated data tables, files, and the like can be stored on a
stationary storage device such as a memory, a hard disk, and a
solid state drive (SSD) or on a portable storage medium such as an
integrated circuit card (ICC), an SD card, and a DVD.
[0097] Further note that the control lines and information lines
shown above represent only those lines necessary to illustrate the
present invention, not necessarily representing all the lines
required as a product. Thus, it can be assumed that almost all the
components are in fact interconnected.
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