U.S. patent application number 14/768927 was filed with the patent office on 2016-01-07 for propeller fan and air conditioner equipped with the same.
The applicant listed for this patent is HITACHI APPLIANCES, INC.. Invention is credited to Atsuhiko FUKASAWA, Taku IWASE, Tetsushi KISHITANI.
Application Number | 20160003487 14/768927 |
Document ID | / |
Family ID | 51390736 |
Filed Date | 2016-01-07 |
United States Patent
Application |
20160003487 |
Kind Code |
A1 |
IWASE; Taku ; et
al. |
January 7, 2016 |
Propeller Fan and Air Conditioner Equipped with the Same
Abstract
In order to suppress that a velocity in the vicinity of a bell
mouth is lowered to induce non-uniformity in velocity at an outlet
of a blade and an outlet of the bell mouth caused by adoption of a
forward-swept blade which makes a tip vortex small as means for
noise reduction, in a blade of a propeller fan, a trailing edge
portion which has been rotationally projected on a plane passing
through a rotational axis is formed from the rotational axis toward
a blade tip portion so as to bend from the suction side to the
discharge side with a first curvature, and is further formed so as
to bend with a second curvature which is smaller than the
aforementioned first curvature with an inflection point
interposed.
Inventors: |
IWASE; Taku; (Tokyo, JP)
; KISHITANI; Tetsushi; (Tokyo, JP) ; FUKASAWA;
Atsuhiko; (Tokyo, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
HITACHI APPLIANCES, INC. |
Minato-ku, Tokyo |
|
JP |
|
|
Family ID: |
51390736 |
Appl. No.: |
14/768927 |
Filed: |
February 22, 2013 |
PCT Filed: |
February 22, 2013 |
PCT NO: |
PCT/JP2013/054451 |
371 Date: |
August 19, 2015 |
Current U.S.
Class: |
165/122 ;
415/121.2; 415/220 |
Current CPC
Class: |
F04D 29/384 20130101;
F04D 29/666 20130101; F04D 29/545 20130101; F24F 1/0029 20130101;
F04D 29/703 20130101; F04D 19/002 20130101; F04D 29/386 20130101;
F05D 2250/713 20130101; F05D 2240/304 20130101; F04D 29/325
20130101 |
International
Class: |
F24F 1/00 20060101
F24F001/00; F04D 29/32 20060101 F04D029/32; F04D 29/38 20060101
F04D029/38; F04D 19/00 20060101 F04D019/00; F04D 29/70 20060101
F04D029/70 |
Claims
1. A propeller fan, comprising: a rotational axis serving as a
center of rotation; and a plurality of blades provided around the
rotational axis, a bell mouth being arranged outside in an outer
radial direction of the plurality of blades, wherein each of the
plurality of blades is formed by a trailing edge portion formed on
the rear relative to a rotation direction, a leading edge portion
formed on the front relative to the rotation direction, a blade tip
portion formed from a tip portion in an outer radial direction of
the trailing edge portion toward a tip portion in an outer radial
direction of the leading edge portion, the trailing edge portion
which has been rotationally projected on a plane passing through
the rotational axis is formed from the rotational axis toward the
blade tip portion so as to bend from the suction side to the
discharge side with a first curvature, and further is formed so as
to bend with a second curvature which is smaller than the first
curvature with an inflection point interposed.
2. The propeller fan according to claim 1, wherein on an end face
of the bell mouth which is closest to the blade, a position which
is an end portion in a discharge direction and where an angle is
changed in an outer radial direction almost matches a position of
the inflection point, viewing from above a rotation plane.
3. The propeller fan according to claim 1, wherein the trailing
edge portion which has been rotationally projected on a plane
vertical to the rotational axis is formed to be convex in a reverse
rotation direction from the rotational axis toward the blade tip
portion, and is formed linearly or to be convex in the rotation
direction with the inflection point interposed.
4. The propeller fan according to claim 1, wherein each of the
plurality of blades is, a blade force acts on a part formed with
the first curvature in the trailing edge portion so as to direct in
an outer radial direction relative to a direction of the rotational
axis and a blade force acts on a part formed with the second
curvature in the trailing edge portion so as to direct in an inner
radial direction relative to the direction of the rotational
axis.
5. The propeller fan according to claim 1, comprising: a guard
which lets air pass toward the discharge side of the blade,
prevents mixing of a foreign material which exceeds a predetermined
size and is apart from the propeller with a distance exceeding a
predetermined length.
6. An air conditioner, comprising: a housing having a suction port
and a discharge port of air; a heat exchanger arranged in the
housing; and a fan which is arranged upstream or downstream of the
heat exchanger and sucks air on the outside of the housing through
the suction port and discharges the air through the discharge port,
wherein the propeller fan according to claim 1 has been used as the
fan.
Description
TECHNICAL FIELD
[0001] The present invention relates to a propeller fan and an air
conditioner equipped with same.
BACKGROUND ART
[0002] The propeller fan is applied to the air conditioner and so
forth in many cases. FIG. 13 shows a plan view of a propeller of a
conventional propeller fan. FIG. 13 is a diagram viewing the
propeller from the discharge side. The propeller is configured by a
plurality of blades provided around a hub. There are many cases
where the blade of a shape (a forward-swept blade) which makes the
blade advance in a rotation direction is adopted, aiming at noise
reduction. The forward-swept blade has an action of making a tip
vortex which flows out from the blade tip small and has an effect
of reducing noise.
[0003] As the background art of the present technical field, there
is Japanese Examined Patent Publication No. Hei2-2000 (Patent
Literature 1). In Patent Literature 1, it is described that air
flow rate enlargement, static pressure heightening and noise
reduction can be made by numerically limiting shape parameters such
as a degree of sweep of the blade and an inclination of the blade,
a camber of the blade section and so forth of the above-mentioned
forward-swept blade.
[0004] In addition, there is Japanese Patent No. 3744489 (Patent
Literature 2). In Patent Literature 2, it is described that the
noise can be reduced by making the tip vortex small by curling an
outer peripheral end part of the blade toward the suction side.
Further, it is also described that the noise can be reduced by
suppressing interaction between an air flow and the bell mouth by
defining a positional relation between such blade and bell
mouth.
[0005] Further, there is Japanese Patent No. 4818184 (Patent
Literature 3). In Patent Literature 3, it is described that the tip
vortex is migrated into a blade tip part by warping the blade
toward the suction side by a definition method different from that
in Patent Literature 2 so as to prevent interaction between the tip
vortex and the bell mouth and thereby noise reduction surd
efficiency heightening can be made.
CITATION LIST
Patent Literature
[0006] PTL 1: Japanese Examined Patent Application Publication No.
Hei2-2000
[0007] PTL 2: Japanese Patent No. 3744489
[0008] PTL 3: Japanese Patent No. 4818184
SUMMARY OF INVENTION
Technical Problem
[0009] In an embodiment, force that a blade acts on a flow will be
referred to as "blade force". The blade force that the blade acts
on the flow is shown by an arrow A' in FIG. 13. In a propeller of a
conventional propeller fan, since the blade has a shape which has
forward sweep in the rotation direction, the blade force acts so as
to direct in an inner radial direction relative to a direction of
the rotational axis 6 just like the arrow A'. Since the flow
obtains a momentum directed in the inner radial direction by this
blade force directed in the inner radial direction, the flow is
directed in the inner radial direction.
[0010] A schematic diagram of a velocity vector which has been
projected on a section passing through a rotational axis 6 in the
conventional propeller fan is shown in FIG. 14. As shown in FIG.
14, since the flow is directed in the inner radial direction, the
flow will not be supplied to the vicinity of the bell mouth which
is arranged so as to cover an outer periphery of the propeller fan,
though not shown. Then, a velocity of air in the vicinity of the
bell mouth is lowered. When the flow is not supplied to the
vicinity of the bell mouth, velocities at the outlet of the blade
and the outlet of the bell mouth become non-uniform, it was the
problem in view of heightening the efficiency of the propeller
fan.
[0011] Accordingly, the present invention aims to promote
heightening of the efficiency of the propeller fan.
Solution to Problem
[0012] In order to solve the above-mentioned problem,
configurations, for example, described in Claims are adopted.
[0013] Although the present application includes a plurality of
means for solving the above-mentioned problem, when one example
thereof is given, a propeller fan includes a rotational axis
serving as a center of rotation and a plurality of blades provided
around the rotational axis, a bell mouth being arranged outside in
an outer radial direction of the plurality of blades, wherein each
of the plurality of blades is formed by a trailing edge portion
formed on the rear relative to a rotation direction, a leading edge
portion formed on the front relative to the rotation direction, a
blade tip portion formed from a tip portion in an outer radial
direction of the trailing edge portion toward a tip portion in an
outer radial direction of the leading edge portion, the
aforementioned trailing edge portion which has been rotationally
projected on a plane passing through the aforementioned rotational
axis is formed from the aforementioned rotational axis toward the
aforementioned blade tip portion so as to bend from the suction
side to the discharge side with a first curvature, and is further
formed so as to bend with a second curvature which is smaller than
the aforementioned first curvature with an inflection point
interposed.
[0014] In addition, in the above-mentioned configuration, it is
desirable that on end face of the aforementioned bell mouth which
is closest to the aforementioned blade, a position which is an end
portion in a discharge direction and where an angle is changed in
an outer radial direction almost match a position of the
aforementioned inflection point, viewing from above a rotation
plane.
[0015] In addition, in the above-mentioned configuration, it is
desirable that the aforementioned trailing edge portion which has
been rotationally projected on a plane vertical to the
aforementioned rotational axis be formed to be convex in a reverse
rotation direction from the aforementioned rotational axis toward
the aforementioned blade tip portion, and be formed linearly or to
be convex in the rotation direction with the inflection point
interposed.
[0016] In addition, in the above-mentioned configuration, it is
desirable that, each of the aforementioned plurality of blades is,
a blade force act on a portion formed with the aforementioned first
curvature in the aforementioned trailing edge portion so as to
direct in an outer radial direction relative to a direction of the
aforementioned rotational axis and a blade force act on a portion
formed with the aforementioned second curvature in the
aforementioned trailing edge portion so as to direct in an inner
radial direction relative to the direction of the aforementioned
rotational axis.
[0017] In addition, in the above-mentioned configuration, it is
desirable to include a guard which lets air pass toward the
discharge side of the aforementioned blade, prevents mixing of a
foreign material which exceeds a predetermined size and is apart
from the propeller with a distance exceeding a predetermined
length.
[0018] Further, it is desirable that, in an air conditioner which
includes a housing having a suction port and a discharge port of
air, a heat exchanger arranged in the housing and a fan which is
arranged upstream or downstream of the heat exchanger and sucks air
on the outside of the housing through the aforementioned suction
port and discharges it through the aforementioned discharge port,
the propeller fan described in any of the above-mentioned
configurations be used as the fan.
Advantageous Effects of Invention
[0019] According to the present invention, efficiency heightening
of the propeller fan can be implemented.
BRIEF DESCRIPTION OF DRAWINGS
[0020] FIG. 1 is a sectional diagram of a plane passing through a
rotational axis of a propeller fan of an embodiment 1.
[0021] FIG. 2 is a diagram explaining a difference in blade force
between the propeller fan of the embodiment 1 and a related art
propeller fan.
[0022] FIG. 3 is a schematic diagram of a velocity vector which has
been projected on a section passing through the rotational axis of
the propeller fan of the embodiment 1.
[0023] FIG. 4 is a sectional diagram of a plane passing through a
rotational axis of a propeller fan of an embodiment 2.
[0024] FIG. 5 is a schematic diagram of a velocity vector which has
been projected on a section passing through the rotational axis of
the propeller fan of the embodiment 2.
[0025] FIG. 6 is one example of comparison in shaft power of the
propeller fan in the embodiment 2 with a conventional propeller
fan.
[0026] FIG. 7 a diagram showing a combination with a bell mouth of
the shape which is different from that in FIG. 4 in the embodiment
2.
[0027] FIG. 8 is a diagram showing a combination with a bell mouth
of the shape which is different from that in FIG. 4 in the
embodiment 2.
[0028] FIG. 9 is a plan view of a propeller in an embodiment 3.
[0029] FIG. 10 is a diagram of a propeller fan in an embodiment
4.
[0030] FIG. 11 is one example of comparison in noise of the
propeller fan in the embodiment 4 with the conventional propeller
fan.
[0031] FIG. 12 is a sectional diagram of an air conditioner in an
embodiment 5.
[0032] FIG. 13 is a plan view of a propeller of the conventional
propeller fan.
[0033] FIG. 14 is a schematic diagram of a velocity vector which
has been projected on the section passing through the rotational
axis in the conventional propeller fan.
DESCRIPTION OF EMBODIMENTS
[0034] In the following, embodiments of the present invention will
be described using the drawings.
Embodiment 1
[0035] An embodiment 1 of the present invention will be described
using FIG. 1 to FIG. 3.
[0036] FIG. 1 is a sectional diagram of a plane passing through a
rotational axis of a propeller fan of the embodiment 1. 1 is a
blade, 2 is a hub, 3 is a trailing edge portion, 4 is a leading
edge portion, 5 is a blade tip portion, 6 is the rotational axis
serving as the center of rotation, X shows a flow direction of air.
The trailing edge portion 3 is formed on the rear relative to a
rotation direction of the blade 1, the leading edge portion 4 is
formed on the front relative to the rotation direction of the blade
1. The blade tip portion 5 is formed from a tip portion in the
radial direction concerned of the trailing edge portion 3 to a tip
portion in the radial direction concerned of the leading edge
portion 4.
[0037] In FIG. 1, the trailing edge portion 3 which has been
rotationally projected on a plane passing through the rotational
axis 6 is shown. The trailing edge portion 3 is formed from the
rotational axis 6 toward the blade-tip portion 5 so as to bend from
the suction side toward the discharge side with a first curvature
.alpha.. Further, it is formed so as to bend with a second
curvature .beta. which is smaller than the first curvature .alpha.
with an inflection point 7 interposed.
[0038] FIG. 2 is a diagram explaining a difference in blade force
between the propeller fan of the embodiment 1 and a related art
propeller fan. FIG. 2 is the diagram viewing the propeller fan from
the discharge side diagonally. A shows a blade force that a part 3b
of the second curvature .beta. of the trailing edge portion 3 of
the propeller fan of the embodiment 1 acts. A' shows a blade force
that a trailing edge portion 3b' on the side of a blade tip portion
5' of the related art propeller fan acts. Y shows a rotation
direction of the blade.
[0039] Since the blade 1 of the propeller fan of the present
embodiment is of the above-mentioned configuration, the blade force
A acts so as to direct in an outer radial direction relative to a
direction of the rotational axis 6. Therefore, a flow in the
vicinity of the trailing edge portion 3b comes to obtain a momentum
which would partially direct in the outer radial direction relative
to the direction of the rotational axis 6. On the other hand, the
blade force A' of the conventional propeller fan acts so as to
direct in an inner radial direction relative to the direction of
the rotational axis 6. Therefore, a flow between blades obtains a
momentum which world direct in the inner radial direction relative
to the direction of the rotational axis 6.
[0040] A schematic diagram of the velocity vector which has been
projected on the section passing through the rotational axis in a
conventional propeller fan is shown in FIG. 14. A flow T in FIG. 14
obtains a momentum directing in the inner radial direction by the
blade force A' which directs in the inner radial direction relative
to the direction of the rotational axis 6 in FIG. 2 and thus comes
to direct in the inner radial direction. Therefore, though not
shown, the flow is not supplied to the vicinity of the bell mouth
which is arranged so as to cover the outer radial direction of the
propeller fan and the velocity in the vicinity of the bell mouth is
lowered. That the flow is not supplied to the vicinity of the bell
mouth means that it will stagnate just like a flow U. Then, the
velocity on the outlet side of the blade becomes non-uniform due to
the flow U in the vicinity of the bell mouth and the flow T and it
could be a factor of efficiency lowering.
[0041] A schematic diagram of a velocity vector which has been
projected on a section passing through the rotational axis in the
propeller fan of the embodiment 1 is shown in FIG. 3. The flow in
the vicinity of the blade tip portion 5 comes to direct by the
action of the bade force in FIG. 2 in the outer radial direction
relative to the rotational axis 6 just like a flow S in FIG. 3.
That is, according to the shape of the trailing edge portion 3 of
the present embodiment, the blade force A acts on a part which is
formed with the first curvature .alpha. in the trailing edge
portion 3 so as to direct in the outer radial direction relative to
the direction of the rotational axis 6 and the blade force acts on
a part which is formed with the second curvature .beta. in the
trailing edge portion 3 so as to direct in the inner radial
direction relative to the direction of the rotational axis 6.
[0042] Consequently, while, conventionally, the flow has stagnated
just like the flow U not being supplied to the vicinity of the bell
mouth as shown in FIG. 14, it is possible to suppress a situation
where the flow U is generated by the action of the blade force A as
observed conventionally. Therefore, since the velocity in the
vicinity of the blade outlet can be made uniform and a mixing loss
of a blade wake is reduced, it becomes possible to increase the
efficiency.
Embodiment 2
[0043] In the present embodiment, an embodiment which can make the
embodiment 1 more highly efficient will be described using FIGS. 4
to 8.
[0044] FIG. 4 is a sectional diagram of a plane passing through the
rotational axis of a propeller fan of an embodiment 2. 8 is a bell
mouth, 9 is a cylindrical portion, 10 shows an end portion of the
bell mouth. The cylindrical portion 9 is a portion of the bell
mouth 8 and covers the blade 1 with a predetermined clearance
interposed. The end portion 10 is an end portion on the discharge
side of the cylindrical portion 9, and the end portion 10 is
arranged so as to match the inflection point 7, viewing from above
the rotation plane, as a position where the angle is changed to a
right angle in the outer radial direction in FIG. 1.
[0045] That is, on an end face of the bell mouth 8 which is closest
to the blade 1, it is made such that the position which is the end
portion 10 in a discharge direction and where the angle is changed
to the outer radial direction almost matches the position of the
inflection point 7, viewing from above the rotation plane. Thereby,
on the end face of the bell mouth 8 which is closest to the blade
1, the position which is the end portion 10 in the discharge
direction and where the angle is changed to the outer radial
direction almost matches a position serving as a boundary between a
portion to which the outward blade force A acts and a portion to
which the outward blade force A does not act, viewing from above
the rotation plane.
[0046] A schematic diagram of a velocity vector which has been
projected on a section passing through the rotational axis in the
propeller fan of the embodiment 2 is shown in FIG. 5. Since the end
portion 10 and the inflection point 7 are arranged so as to almost
match mutually, a velocity distribution which has been made uniform
by the action of the blade force in the arrow A direction shown in
FIG. 2 in the embodiment 1 is maintained with no dispersion of the
flow by the cylindrical portion 9. Therefore, the operational
effect of the embodiment 1 can be more surely obtained and the
efficiency of the propeller fan can be increased.
[0047] A result of comparison in shaft power of the propeller fan
in the embodiment 2 with the conventional propeller fan is shown in
FIG. 6. In the vicinity of an operating point, the power
consumption of the propeller fan of the embodiment 2 is
energy-saved by 3.3% in comparison with the conventional propeller
fan, that is, efficiency heightening is obtained.
[0048] FIG. 7 and FIG. 8 are diagrams showing combinations with
bell mouths of shapes different from that in FIG. 4 in the
embodiment 2. The bell mouth in FIG. 7 is arched on the discharge
side of the cylindrical portion 9. In this case, an end portion 10a
serves as a contact point between a straight line and an arch of
the cylindrical portion 9. The bell mouth in FIG. 8 is conically
tapered on the discharge side of the cylindrical portion 9. In this
case, an end portion 10b serves as a contact point between the
straight line and the conical taper of the cylindrical portion 9.
As shown, the end portions 10a and 10b are arranged so as to match
the inflection point 7, viewing from above the rotation plane. The
operational effect obtained by the present invention is, the same
advantageous effect as that of the bell mouth in FIG. 4 can be
obtained also in any of the bell mouths in FIG. 7 and FIG. 8.
Embodiment 3
[0049] In the present embodiment, an embodiment which can make the
embodiment 1 or the embodiment 2 more highly efficient will be
described using FIG. 9 and FIG. 10.
[0050] FIG. 9 is a plan view of a propeller in an embodiment 3.
FIG. 9 is the diagram that the propeller has been viewed from the
discharge side. In FIG. 9, the trailing edge portion 3 is projected
on a plane which is vertical to the rotational axis. The trailing
edge portion 3 is formed into a convex shape in a reverse rotation
direction from the hub 2 toward the blade tip portion 5 and is
formed to be convex in the rotation direction with an inflection
point 18 interposed. B is a blade force that the vicinity of a
trailing edge portion 3h on the hub 2 side acts, C shows a blade
force that the vicinity of a trailing edge portion 3t on the blade
tip portion 5 side acts. It is desirable that the inflection point
18 have the same radius as the inflection point described in the
embodiments 1 and 2.
[0051] Since the curvature of the trailing edge portion 3t has been
changed with the inflection point 18 set as a boundary, the
orientation of the blade force C is changed to the outer radial
direction relative to the direction of the rotational axis 6 in
comparison with the blade force B. Owing to this change in
orientation of the blade force, the flow in the vicinity of the
trailing edge portion 3t obtains a momentum which directs in the
outer radial direction and the flow in the vicinity of the blade
tip portion 5 is directed in the outer radial direction.
Consequently, the velocity in the vicinity of the blade outlet is
made uniform. Since the mixing loss of the blade wake is reduced by
velocity uniformity, the efficiency is increased.
[0052] Incidentally, although in FIG. 9, the trailing edge portion
3t is formed to be convex in the rotation direction, the operation
which is the same as the above-mentioned one can be obtained by
further linearly changing it in a direction that the curvature of
the trailing edge portion 3t is made large relative to the trailing
edge portion 3h with the inflection point 18 interposed.
Embodiment 4
[0053] In the present embodiment, an embodiment that the effect of
noise reduction can be also obtained in addition to efficiency
heightening in the embodiments 1 to 3 will be described using FIG.
10 and FIG. 11.
[0054] FIG. 10 is a diagram of a propeller fan in an embodiment 4.
FIG. 10 is the one that a guard is arranged on the blade wake side
of the propeller fan in the embodiments 1 to 3. This guard is of
the type which is formed into a frame-like shape or a net-like
shape so as to pass air to the discharge side of the blade and
prevents mixing of the foreign material which exceeds a
predetermined size through gaps in the frame or the net. The
velocities in the vicinity of the blade outlets of the propeller
fans in the embodiments 1 to 3 are made uniform in comparison with
that of the conventional propeller fan. Since noise caused by the
flow is proportional to the sixth power of a flow rate, the noise
generated from a guard 11 is, in a case where the velocity is
locally large, the noise generated from that portion becomes
predominant. Accordingly, in the present embodiment 3 that the
velocity has been made uniform, the noise is reduced in comparison
with a combination with the conventional propeller fan.
[0055] One example of comparison in noise of the propeller fan in
the embodiment 3 with the conventional propeller fan is shown in
FIG. 11. It is confirmed that the noise of the propeller fan in the
embodiment 3 is reduced by approximately 1 dB in comparison with
that of the conventional propeller fan.
[0056] Incidentally, it is necessary to form the gap in the frame
or the net of this guard 11 to be less than a predetermined size
such that a finger of an adult does not enter it. Further, it is
necessary to make it not to touch a propeller 12 even in a case
where a finger of a child has entered the gap in the guard 11.
Therefore, further safety can be ensured by setting a distance L
from an end portion of the frame or the net of the guard 11 to a
position 19 where the trailing edge 3 is closest to the guard 11 so
as to exceed a predetermined length. Since it is assumed that the
length of the finger of the child is approximately 50 mm, it is
desirable to ensure 50 mm or more as the distance L.
Embodiment 5
[0057] In the present embodiment, an air conditioner using a
propeller fan equipped with requirements of any of the embodiments
1 to 4 will be described.
[0058] FIG. 12 is a sectional diagram of the air conditioner in an
embodiment 5. This air conditioner is an outdoor unit, in FIG. 12,
the propeller 12 rotates by being fixed to and supported by a motor
13, a motor support table 14. The bell mouth 8 is arranged on an
outer periphery of the propeller 12. The guard 11 is arranged in a
downstream area thereof. A heat exchanger 16 is installed upstream
of the propeller 12 in a unit 15. A compressor 17 is loaded in the
unit 15.
[0059] This air conditioner is, after air has been sucked into and
cooled or overheated by the heat exchanger 16 by rotating the
propeller 12 by the motor 13, it is boosted by the propeller 12 and
the bell mouth 8 and thereafter is discharged through the guard 11.
Since the propeller fan described in any of the embodiments 1 to 4
is used as the propeller fan and the bell mouth, the noise-reduced
and highly efficient air conditioner can be obtained.
[0060] Incidentally, although the outdoor unit has been described
in the present embodiment, the present invention is a technology
which can be commonly used in the ones using the propeller fan
regardless of whether the air conditioner is of another type and an
indoor unit.
REFERENCE SIGNS LIST
[0061] 1, 1': blade
[0062] 2, 2': hub
[0063] 3, 3', 3t, 3h: trailing edge portion
[0064] 4, 4': leading edge portion
[0065] 5, 5': blade tip portion
[0066] 6, 6': center of rotation
[0067] 7: inflection point
[0068] 8: bell mouth
[0069] 9: cylindrical portion
[0070] 10, 10a, 10b: end portion
[0071] 11: guard
[0072] 12: propeller
[0073] 13: motor
[0074] 14: motor support table
[0075] 15: unit
[0076] 16: heat exchanger
[0077] 17: compressor
[0078] 18: inflection point
[0079] 19: position where the trailing edge 3 is closest to the
guard 11 from the end portion of the frame or the net of the guard
11
[0080] A, A': blade force
[0081] B: blade force
[0082] C: blade force
[0083] L: distance
[0084] S: flow
[0085] T: flow
[0086] U: flow
[0087] X: air flowing direction
[0088] Y: rotation direction
[0089] A: first curvature
[0090] B: second curvature
* * * * *