U.S. patent application number 14/423495 was filed with the patent office on 2015-07-23 for propeller fan.
This patent application is currently assigned to Mitsubishi Electric Corporation. The applicant listed for this patent is Atsushi KONO, Takahide TADOKORO. Invention is credited to Atsushi Kono, Takahide Tadokoro.
Application Number | 20150204345 14/423495 |
Document ID | / |
Family ID | 50434493 |
Filed Date | 2015-07-23 |
United States Patent
Application |
20150204345 |
Kind Code |
A1 |
Kono; Atsushi ; et
al. |
July 23, 2015 |
PROPELLER FAN
Abstract
Provided is a propeller fan, including: a boss section including
a tubular wall; and a plurality of blades extending in a radiate
manner from an outer peripheral surface of the tubular wall of the
boss section. Secondary flow control slits are each formed between
a pair of the adjacent blades on the outer peripheral surface. The
slit passes through the tubular wall to communicate between an
inside of the boss section and an outside of the boss section. A
downstream end of the tubular wall is closed, whereas an upstream
end of the tubular wall is open. In side view, the slit extends
obliquely to a rotation axis of the propeller fan, and extends
obliquely in the same direction as a forming direction of a blade
root portion of each of the plurality of blades.
Inventors: |
Kono; Atsushi; (Tokyo,
JP) ; Tadokoro; Takahide; (Tokyo, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KONO; Atsushi
TADOKORO; Takahide |
Tokyo
Tokyo |
|
JP
JP |
|
|
Assignee: |
Mitsubishi Electric
Corporation
Tokyo
JP
|
Family ID: |
50434493 |
Appl. No.: |
14/423495 |
Filed: |
October 3, 2012 |
PCT Filed: |
October 3, 2012 |
PCT NO: |
PCT/JP2012/075656 |
371 Date: |
February 24, 2015 |
Current U.S.
Class: |
415/177 ;
415/208.1; 416/223R |
Current CPC
Class: |
F04D 25/02 20130101;
F04D 29/325 20130101; F04D 29/329 20130101; F04D 19/002 20130101;
F04D 29/684 20130101; F04D 29/682 20130101 |
International
Class: |
F04D 29/32 20060101
F04D029/32; F04D 25/02 20060101 F04D025/02; F04D 19/00 20060101
F04D019/00 |
Claims
1. A propeller fan, comprising: a boss comprising a tubular wall;
and a plurality of blades being provided on an outer peripheral
surface of the tubular wall of the boss, wherein a slit is formed
on the outer peripheral surface, wherein each of a plurality of the
slits passes through the tubular wall to communicate between an
inside of the boss and an outside of the boss, wherein a downstream
end of the tubular wall is closed, whereas an upstream end of the
tubular wall is open, and wherein, in side view, the each of the
plurality of the slits extends obliquely in the same direction as a
forming direction of a blade root of each of the plurality of
blades.
2. A propeller fan according to claim 1, wherein, assuming that VL1
represents an imaginary line connecting a plurality of leading
edges at positions of the blade roots of the blades, and VL2
represents an imaginary line connecting a plurality of trailing
edges, the slit is formed in a range between the imaginary line VL1
and the imaginary line VL2.
3. A propeller fan according to claim 2, wherein, assuming that VL3
represents an imaginary line extending along an intermediate
position between the pair of the adjacent blades, the slit is
arranged in a forward region in a rotating direction of the
propeller fan with respect to the imaginary line VL3.
4. A propeller fan according to claim 3, wherein, assuming that a
line positioned at equal distances from the pair of imaginary lines
VL1 and VL2 is represented as an imaginary line VL4, and that when
P represents an intersection point between the imaginary line VL4
and a camber line of the forward blade of a pair of the
corresponding blades in the rotating direction of the propeller
fan, a line segment joining a leading edge of a corresponding
backward blade and the intersection point P on the corresponding
forward blade is represented as an imaginary line VL5, slit is
arranged in a backward region in the rotating direction of the
propeller fan with respect to the imaginary line VL5.
5. A propeller fan according to claim 1, wherein the slit extends
in parallel to a camber of the blades.
6. A propeller fan according to claim 1, wherein the slit has a
width of one tenth or less of a circumferential distance (L)
between the pair of the corresponding blades.
7. An air blower, comprising: the propeller fan of claim 1; a
driving source for applying a driving force to the propeller fan;
and a casing in which the propeller fan and the driving source are
housed.
8. An outdoor unit, comprising: a heat exchanger; the propeller fan
of claim 1; a driving source for applying a driving force to the
propeller fan; and a casing in which the propeller fan, the driving
source, and the heat exchanger are housed.
Description
TECHNICAL FIELD
[0001] The present invention relates to a propeller fan, an air
blower, and an outdoor unit.
BACKGROUND ART
[0002] In general, a propeller fan includes a cylindrical boss
connected to a driving source, and a plurality of blades extending
in a radiate manner from an outer peripheral surface of the boss.
Further, in Patent Literature 1, there is disclosed such a
configuration that, in each blade, a position at which a camber
ratio is maximum is set to a position closer to a blade root
portion than an outer peripheral edge of the blade, and the camber
ratio is gradually decreased toward the blade root portion from the
position at which the camber ratio is maximum. With this
configuration, occurrence of a vortex is suppressed without causing
the blade to exert a large amount of work in the vicinity of the
blade root portion.
CITATION LIST
Patent Literature
[0003] [PTL 1] JP 2012-052443 A (mainly FIG. 1)
SUMMARY OF INVENTION
Technical Problem
[0004] By the way, the Coriolis force acting in a direction reverse
to a rotating direction of the propeller fan balances with a
pressure gradient between adjacent blade surfaces, and thus an air
current between the blades flows along the blades. However, the
above-mentioned pressure gradient influences up to the outer
peripheral surface of the boss, whereas relative velocity of the
air current is low in a boundary layer on the outer peripheral
surface of the boss, with the result that the Coriolis force is
reduced. Accordingly, the above-mentioned balance is lost in the
vicinity of the outer peripheral surface of the boss, and due to
the influence of the above-mentioned pressure gradient, a secondary
flow toward an adjacent blade is generated. The secondary flow
collides with the blade, and thus a vortex occurs, which causes
noise.
[0005] On the other hand, according to the propeller fan disclosed
in Patent Literature 1, the camber ratio is gradually decreased
toward the blade root portion from the position at which the camber
ratio is maximum, thereby being capable of suppressing a vortex,
which may occur at a connecting portion between the blade and the
boss. However, there is a problem in that an amount of work of the
blade is reduced in the vicinity of the connecting portion between
the blade and the boss.
[0006] The present invention has been made in view of the above,
and has an object to provide a propeller fan capable of suppressing
a vortex, which may occur at a connecting portion between a blade
and a boss, thereby reducing a noise level of the fan without
depending on setting of a camber ratio of the blade in the vicinity
of a blade root portion.
Solution to Problem
[0007] In order to attain the above-mentioned object, according to
one embodiment of the present invention, there is provided a
propeller fan, including: a boss section including a tubular wall;
and a plurality of blades extending in a radiate manner from an
outer peripheral surface of the tubular wall of the boss section.
Secondary flow control slits are each formed between a pair of the
adjacent blades on the outer peripheral surface. Each of a
plurality of the secondary flow control slits passes through the
tubular wall to communicate between an inside of the boss section
and an outside of the boss section. A downstream end of the tubular
wall is closed, whereas an upstream end of the tubular wall is
open. In side view, the each of the plurality of the secondary flow
control slits extends obliquely to a rotation axis of the propeller
fan, and extends obliquely in the same direction as a forming
direction of a blade root portion of each of the plurality of
blades.
[0008] In order to attain the object, according to one embodiment
of the present invention, there is provided an air blower,
including: the above-mentioned propeller fan according to the one
embodiment of the present invention; a driving source for applying
a driving force to the propeller fan; and a casing in which the
propeller fan and the driving source are housed.
[0009] Further, in order to attain the object, according to one
embodiment of the present invention, there is provided an outdoor
unit, including: a heat exchanger; the above-mentioned propeller
fan according to the one embodiment of the present invention; a
driving source for applying a driving force to the propeller fan;
and a casing in which the propeller fan, the driving source, and
the heat exchanger are housed.
Advantageous Effects of Invention
[0010] In the propeller fan according to the one embodiment of the
present invention, it is possible to suppress the vortex, which may
occur at the connecting portion between the blade and the
boss,thereby reducing the noise level of the fan without depending
on the setting of the camber ratio of the blade in the vicinity of
the blade root portion.
BRIEF DESCRIPTION OF DRAWINGS
[0011] FIG. 1 is a perspective view illustrating a propeller fan
according to a first embodiment of the present invention as viewed
from a downstream side.
[0012] FIG. 2 is a side view illustrating the propeller fan
according to the first embodiment.
[0013] FIG. 3 is a view illustrating an air current flowing over an
outer peripheral surface of a boss of the propeller fan according
to the first embodiment.
[0014] FIG. 4 is a view illustrating an air current passing through
a slit in the outer peripheral surface of the boss of the propeller
fan according to the first embodiment.
[0015] FIG. 5 is a view illustrating a position of a slit formed in
the outer peripheral surface of the boss according to a second
embodiment of the present invention.
[0016] FIG. 6 is a view illustrating a position of a slit formed in
the outer peripheral surface of the boss according to a third
embodiment of the present invention.
[0017] FIG. 7 is a view illustrating a position of a slit formed in
the outer peripheral surface of the boss according to a fourth
embodiment of the present invention.
[0018] FIG. 8 is a view illustrating a shape of a slit formed in
the outer peripheral surface of the boss according to a fifth
embodiment of the present invention.
[0019] FIG. 9 is a view illustrating a shape of a slit formed in
the outer peripheral surface of the boss according to a sixth
embodiment of the present invention.
[0020] FIG. 10 is a view illustrating an air current passing
between blades of a propeller fan according to a comparative
example.
[0021] FIG. 11 is a perspective view illustrating an outdoor unit
according to a seventh embodiment of the present invention as
viewed from an air outlet side thereof.
[0022] FIG. 12 is a view illustrating a configuration of the
outdoor unit according to the seventh embodiment as viewed from a
top surface side thereof.
[0023] FIG. 13 is a view illustrating a state in which a fan grille
is removed according to the seventh embodiment.
[0024] FIG. 14 is a view illustrating an internal configuration in
a state in which a front panel and the like are further removed
according to the seventh embodiment.
DESCRIPTION OF EMBODIMENTS
[0025] Now, a propeller fan according to embodiments of the present
invention is described with reference to the accompanying drawings.
Note that, in the drawings, the same reference symbols represent
the same or corresponding parts.
First Embodiment
[0026] FIG. 1 is a perspective view illustrating a propeller fan
according to a first embodiment of the present invention as viewed
from a downstream side. FIGS. 2, 3, and 4 are a side view
illustrating the propeller fan, a view illustrating an air current
flowing over an outer peripheral surface of a boss, and a view
illustrating an air current passing through a slit, respectively. A
propeller fan 1 includes a boss section 3 and a plurality of blades
5.
[0027] The boss section 3 includes a tubular wall 3a having a
cylindrical shape. An output shaft of a driving source such as a
motor is connected to a center portion 3b of the boss section 3,
and the propeller fan 1 is rotated by a driving force of the
driving source. Note that, reference symbol RD of FIG. 1 represents
a rotating direction of the propeller fan 1, and reference symbol
RA of FIG. 2 represents a rotation axis of the propeller fan 1.
Reference symbol US conceptually represents an upstream air
current, and reference symbol DS conceptually represents a
downstream air current.
[0028] As illustrated best in FIG. 4, a downstream end of the
tubular wall 3a of the boss section 3 is closed by a lid plate
portion 3c. On the other hand, an upstream end of the tubular wall
3a of the boss section 3 is open. With this configuration, an
inside of the boss section 3 and an outside of the boss section 3
are communicated to each other.
[0029] The plurality of blades 5 extend in a radiate manner from an
outer peripheral surface 3d of the tubular wall 3a of the boss
section 3. Further, the plurality of blades 5 have mutually the
same shape, and are provided at equal intervals. The blades 5 each
include an outer peripheral edge 5a, a blade root portion 5b, a
leading edge 5c, a trailing edge 5d, a positive pressure surface
5e, and a negative pressure surface 5f.
[0030] The outer peripheral edge 5a is an edge portion of each
blade 5 on a radially outer side thereof, and is also an edge
portion extending in a circumferential direction. By contrast, the
blade root portion 5b is a portion of each blade 5 connected to the
outer peripheral surface 3d of the boss section 3. The leading edge
5c is an edge portion connecting a leading end of the outer
peripheral edge 5a and a leading end of the blade root portion 5b,
and is also an edge portion on a forward side in the rotating
direction of the propeller fan 1. Similarly, the trailing edge 5d
is an edge portion connecting a trailing end of the outer
peripheral edge 5a and a trailing end of the blade root portion 5b,
and is also an edge portion on a backward side in the rotating
direction of the propeller fan 1. In the illustrated configuration,
both the leading edge 5c and the trailing edge 5d are curved so as
to extend onward in the rotating direction toward the radially
outer side.
[0031] In plan view, the positive pressure surface 5e and the
negative pressure surface 5f are each a blade surface defined by
the outer peripheral edge 5a, the blade root portion 5b, the
leading edge 5c, and the trailing edge 5d. The positive pressure
surface 5e and the negative pressure surface 5f are positioned so
as to have a mutually front-and-back relationship. The positive
pressure surface 5e is a blade surface on a downstream side of an
air current generated through rotation of the propeller fan 1, and
the negative pressure surface 5f is a blade surface on an upstream
side of the air current. Further, in the illustrated configuration,
the positive pressure surface 5e is a concave surface concaved
toward the downstream side, and the negative pressure surface 5f is
a convex surface convexed toward the upstream side.
[0032] Secondary flow control slits 7 are each formed between a
pair of adjacent blades 5 on the outer peripheral surface 3d of the
boss section 3. As illustrated best in FIG. 4, each of the
plurality of secondary flow control slits 7 in the entire outer
peripheral surface 3d of the boss section 3 passes through the
tubular wall 3a of the boss section 3 to communicate between the
inside of the boss section 3 and the outside of the boss section
3.
[0033] Further, as illustrated best in FIG. 2, in side view, each
of the plurality of secondary flow control slits 7 extends
obliquely to the rotation axis RA of the propeller fan, and extends
obliquely in the same direction as a forming direction of the blade
root portion 5b of each of the plurality of blades 5. In the
illustrated configuration, each of the secondary flow control slits
7 extends straight in side view, and is inclined so that a forward
portion thereof in the rotating direction of the propeller fan is
positioned on the upstream side of the air current.
[0034] Next, air-blowing operation of the propeller fan according
to the first embodiment is described. First, with reference to FIG.
10, description is made of a flow in a propeller fan according to a
comparative example, which does not have a feature of the present
invention. At a radial center portion of each blade 55, as
indicated by the arrow F3, an air current flowing into the
propeller fan from the upstream side flows along the blade 55 to
the downstream side. On the other hand, on an outer peripheral
surface of a boss section 53, as indicated by the arrow F4, an air
current flowing into the propeller fan from the upstream side flows
from the vicinity of a leading edge 55c of a positive pressure
surface 55e of the blade 55 toward a negative pressure surface 55f
of an adjacent blade 55, and then flows to the downstream side
while forming a vortex.
[0035] That is, at a radial center portion between the blades, the
Coriolis force acting in a direction reverse to the rotating
direction balances with a pressure gradient from the positive
pressure surface 55e of the blade 55 to the negative pressure
surface 55f of the adjacent blade 55, and thus the air current
between the blades 55 is formed into a flow along the blades 55.
However, the above-mentioned pressure gradient influences up to the
outer peripheral surface of the boss section 53, whereas relative
velocity of the air current is low in a boundary layer on the outer
peripheral surface of the boss section 53, with the result that the
Coriolis force is reduced. Accordingly, due to the influence of the
above-mentioned pressure gradient, a secondary flow toward the
negative pressure surface of the adjacent blade is generated. The
secondary flow collides with the negative pressure surface, and
thus a vortex occurs.
[0036] In contrast, in the first embodiment, an upstream end
surface of the boss section 3 is open, and the inside of the boss
section 3 is communicated to the upstream side of the propeller fan
1. In the outer peripheral surface of the boss section 3, the
secondary flow control slit 7 connecting the inside and the outside
of the boss section 3 is formed across a region between the blades.
Accordingly, in a case where pressure in the region between the
blades is higher than pressure in the inside of the boss section 3,
as indicated by the solid arrow F1 of FIGS. 3 and 4, the secondary
flow is sucked into the inside of the boss section 3 through the
secondary flow control slit 7 formed in the outer peripheral
surface 3d of the boss section 3. The secondary flow is sucked into
the inside of the boss section 3, and hence the air current flowing
toward the negative pressure surface 5f can be suppressed. Thus, it
is possible to suppress turbulence of the air current, which maybe
caused by occurrence of a vortex. Conversely, in a case where the
pressure in the region between the blades is lower than the
pressure in the inside of the boss section 3, as indicated by the
dotted arrow F2 of FIGS. 3 and 4, such an air current is generated
as to flow out from the inside of the boss section 3 to the outside
of the boss section 3 through the secondary flow control slit 7
formed in the outer peripheral surface 3d of the boss section 3.
Due to the above-mentioned air current, the secondary flow is
separated from the boundary layer on the outer peripheral surface
3d of the boss section 3, and hence the air current flowing toward
the negative pressure surface 5f can be suppressed. Accordingly, it
is possible to suppress turbulence of the air current, which may be
caused by occurrence of a vortex.
[0037] Further, with respect to the rotation axis RA of the
propeller fan, the secondary flow control slit 7 is inclined in the
same direction as a direction of inclination of the blades 5.
Hence, the secondary flow control slit 7 can exert a reduced action
on the air current parallel to the blades 5. In addition, the
secondary flow control slit 7 is orthogonal to the secondary flow,
thereby being capable of increasing the above-mentioned effect of
suppressing occurrence of a vortex.
[0038] As described above, according to the propeller fan of the
first embodiment, the secondary flow control slit suppresses a
vortex, which may occur at a connecting portion between the blade
and the boss, thereby being capable of reducing the noise level of
the fan. Further, this configuration does not depend on setting of
a camber ratio of the blade in the vicinity of the blade root
portion, thereby being capable of suppressing occurrence of a
vortex while causing the blade to effectively work on a region up
to the vicinity of the blade root portion.
Second Embodiment
[0039] FIG. 5 is a view illustrating a position of a slit formed in
the outer peripheral surface of the boss according to a second
embodiment of the present invention. FIG. 5 illustrates a partial
developed state of the outer peripheral surface 3d of the boss
section 3. FIG. 5 illustrates the blade root portions 5b of the
pair of blades 5 and a secondary flow control slit 107 positioned
between the blade root portions 5b.
[0040] In FIG. 5, an imaginary line VL1 connecting the plurality of
leading edges 5c at positions of the blade root portions 5b, and an
imaginary line VL2 connecting the plurality of trailing edges 5d at
positions of the blade root portions 5b are assumed. In the second
embodiment, the secondary flow control slit 107 is formed in a
range between the imaginary line VL1 and the imaginary line VL2.
Note that, the other features of the secondary flow control slit
107 may be the same as those of the above-mentioned secondary flow
control slit 7 according to the first embodiment.
[0041] Also in the second embodiment, similarly to the
above-mentioned first embodiment, it is possible to suppress a
vortex, which may occur at the connecting portion between the blade
and the boss, thereby being capable of reducing the noise level of
the fan. In particular, in the second embodiment, the secondary
flow control slit is limitedly formed in a range in which the
pressure gradient between the blades is large and the secondary
flow is easily generated, and hence it is possible to suppress
occurrence of a vortex while reducing an influence on a primary
flow.
Third Embodiment
[0042] FIG. 6 is a view illustrating a position of a slit formed in
the outer peripheral surface of the boss according to a third
embodiment of the present invention, and is also a view similar to
FIG. 5. In FIG. 6, in addition to the same imaginary lines VL1 and
VL2 as those of FIG. 5, an imaginary line VL3 is assumed. The
imaginary line VL3 extends along an intermediate position between
the pair of adjacent blades (blade root portions 5b) in a
circumferential direction. More specifically, the imaginary line
VL3 is a line obtained by aligning, from a pair of leading edges to
a pair of trailing edges, circumferential middle points between a
pair of camber lines (blade thickness center lines) CL of the pair
of adjacent blades.
[0043] In the third embodiment, a secondary flow control slit 207
extends in a range between the imaginary line VL1 and the imaginary
line VL2, and is arranged in a forward region in the rotating
direction RD of the propeller fan with respect to the imaginary
line VL3. Note that, the other features of the secondary flow
control slit 207 may be the same as those of the above-mentioned
secondary flow control slit 7 according to the first
embodiment.
[0044] Also in the third embodiment, the same advantage as that of
the above-mentioned second embodiment can be obtained. In addition,
in the third embodiment, the secondary flow control slit 207 is
formed at a position closer to the negative pressure surface 5f
where the secondary flow becomes strongest (that is, a position
closer to the negative pressure surface 5f than the positive
pressure surface 5e), and hence an effect of suppressing the
secondary flow can be significantly obtained.
Fourth Embodiment
[0045] FIG. 7 is a view illustrating a position of a slit formed in
the outer peripheral surface of the boss according to a fourth
embodiment of the present invention, and is also a view similar to
FIG. 5. In FIG. 7, in addition to the same imaginary lines VL1,
VL2, and VL3 as those of FIG. 6, imaginary lines VL4 and VL5 are
assumed.
[0046] First, with reference to FIG. 7, the imaginary line VL4 is a
line positioned at equal distances from the pair of imaginary lines
VL1 and VL2. In other words, the imaginary line VL4 is a line
extending along an intermediate position between the pair of
imaginary lines VL1 and VL2 in a direction of the rotation axis of
the propeller fan. Further, when, in FIG. 7, P represents an
intersection point between the imaginary line VL4 and the camber
line (blade thickness center line) CL of the forward blade 5 of the
pair of corresponding blades 5 in the rotating direction RD of the
propeller fan, a line segment joining the leading edge 5c of the
corresponding backward blade 5 and the intersection point P on the
corresponding forward blade 5 is assumed as the imaginary line
VL5.
[0047] Further, in the fourth embodiment, a secondary flow control
slit 307 extends in the range between the imaginary line VL1 and
the imaginary line VL2, and is arranged in the forward region in
the rotating direction RD of the propeller fan with respect to the
imaginary line VL3 and in a backward region in the rotating
direction RD of the propeller fan with respect to the imaginary
line VL5. In other words, with reference to FIG. 7, the secondary
flow control slit 307 is arranged in a region surrounded by the
imaginary line VL2, the imaginary line VL3, the imaginary line VL5,
and the forward blade 5 of the pair of corresponding blades 5 in
the rotating direction RD of the propeller fan. Note that, the
other features of the secondary flow control slit 207 may be the
same as those of the above-mentioned secondary flow control slit 7
according to the first embodiment.
[0048] Also in the fourth embodiment, the same advantage as that of
the above-mentioned third embodiment can be obtained. In addition,
the secondary flow is considerably easily generated in a region
ranging from the vicinity of the leading edge of the backward blade
connected to the boss section to the vicinity of a midpoint between
the leading edge and the trailing edge of the adjacent forward
blade or the trailing edge of the adjacent forward blade. In this
context, the fourth embodiment has such an advantage that an action
exerted by the secondary flow control slit can be obtained more
intensively in the region where the secondary flow is considerably
easily generated.
Fifth Embodiment
[0049] FIG. 8 is a view illustrating a position of a slit formed in
the outer peripheral surface of the boss according to a fifth
embodiment of the present invention, and is also a view similar to
FIG. 5. As illustrated in FIG. 8, a secondary flow control slit 407
according to the fifth embodiment extends in parallel to a camber
of the blade 5. In particular, the secondary flow control slit 407
illustrated in FIG. 8 is a limited example of the fifth embodiment.
However, in an arrangement mode of the secondary flow control slit
according to the above-mentioned fourth embodiment (in FIG. 8, an
imaginary line and an intersection point are not shown), the
secondary flow control slit 407 is further formed so as to be
curved in parallel to the camber of the blade 5. Note that, the
secondary flow control slit according to the fifth embodiment
corresponds to the secondary flow control slit according to anyone
of the above-mentioned first to fourth embodiments, which extends
in parallel to the camber of the blade, and is not always limited
to the state illustrated in FIG. 8.
[0050] Also in the fifth embodiment, at least the same advantage as
that of the above-mentioned first embodiment can be obtained. In
addition, the secondary flow control slit is parallel also to the
primary flow of the air current generated between the blades, and
hence it is possible to reduce the influence on the primary
flow.
Sixth Embodiment
[0051] FIG. 9 is a view illustrating a position of a slit formed in
the outer peripheral surface of the boss according to a sixth
embodiment of the present invention, and is also a view similar to
FIG. 5. As illustrated in FIG. 9, a secondary flow control slit 507
according to the sixth embodiment extends so as to have a width of
one tenth or less of a circumferential inter-blade distance L
between the pair of corresponding blades 5 (dimension in a
direction orthogonal to an extending direction of the slit).
Further, the other configurations of the secondary flow control
slit 507 are the same as those of the secondary flow control slit
according to any one of the above-mentioned first to fifth
embodiments.
[0052] Also in the sixth embodiment, at least the same advantage as
that of the above-mentioned first embodiment can be obtained.
Further, it is possible to reduce the influence on the primary
flow, which may be caused due to an increased amount of the air
current passing through the secondary flow control slit.
Seventh Embodiment
[0053] FIG. 11 is a perspective view illustrating an outdoor unit
(air blower) according to a seventh embodiment as viewed from an
air outlet side thereof, and FIG. 12 is a view illustrating a
configuration of the outdoor unit as viewed from a top surface side
thereof. Further, FIG. 13 illustrates a state in which a fan grille
is removed, and FIG. 14 is a view illustrating an internal
configuration in a state in which a front panel and the like are
further removed.
[0054] As illustrated in FIGS. 11 to 14, an outdoor-unit main body
(casing) 51 is formed as a casing including a pair of right and
left side surfaces 51a, 51c, a front surface 51b, aback surface
51d, a top surface 51e, and a bottom surface 51f. The side surface
51a and the back surface 51d each have an opening portion through
which the air is sucked from an outside of the outdoor-unit main
body (see the arrows A of FIG. 12). Further, in a front panel 52 of
the front surface 51b, an air outlet 53 is formed as an opening
portion through which the air is blown out to the outside (see the
arrows A of FIG. 12). In addition, the air outlet 53 is covered
with a fan grille 54. This configuration prevents contact between
an object, etc. and the propeller fan 1, to thereby assure
safety.
[0055] The propeller fan 1 is mounted in the outdoor-unit main body
51. The propeller fan 1 is the propeller fan according to any one
of the above-mentioned first to sixth embodiments. The propeller
fan 1 is connected to a fan motor (driving source) 61 on the back
surface 51d side through intermediation of a rotation shaft 62, and
is rotated and driven by the fan motor 61.
[0056] An inside of the outdoor-unit main body 51 is partitioned by
a partition plate (wall) 51g into an air-blowing chamber 56 in
which the propeller fan 1 is housed and mounted, and a machine
chamber 57 in which a compressor 64 and the like are mounted. On
the side surface 51a side and the back surface 51d side in the
air-blowing chamber 56, a heat exchanger 68 extending in
substantially an L-shape in plan view is provided.
[0057] A bellmouth 63 is arranged on a radially outer side of the
propeller fan 1 arranged in the air-blowing chamber 56. The
bellmouth 63 is positioned on an outer side of the outer peripheral
edge of each of the blades 5, and exhibits an annular shape along
the rotating direction of the propeller fan 1. Further, the
partition plate 51g is positioned on one side of the bellmouth 63
(on a right side in the drawing sheet of FIG. 12), and a part of
the heat exchanger 68 is positioned on another side (opposite side)
thereof (on a left side in the drawing sheet of FIG. 12).
[0058] A front end of the bellmouth 63 is connected to the front
panel 52 of the outdoor unit so as to surround an outer periphery
of the air outlet 53. Note that, the bellmouth 63 may be formed
integrally with the front panel 52, or may be prepared as a
separate component to be connected to the front panel 52. Due to
the bellmouth 63, a flow passage between an air inlet side and an
air outlet side of the bellmouth 63 is formed as an air passage in
the vicinity of the air outlet 53. That is, the air passage in the
vicinity of the air outlet 3 is partitioned by the bellmouth 63
from another space in the air-blowing chamber 56.
[0059] The heat exchanger 68 provided on the air inlet side of the
propeller fan 1 includes a plurality of fins aligned side by side
so that respective plate-like surfaces are parallel to each other,
and heat-transfer pipes passing through the respective fins in an
aligning direction of the fins. A refrigerant, which circulates
through a refrigerant circuit, flows in the heat-transfer pipes. In
the heat exchanger 68 according to this embodiment, the
heat-transfer pipes extend in an L-shape along the side surface 51a
and the back surface 51d of the outdoor-unit main body 51, and as
illustrated in FIG. 14, the heat-transfer pipes in a plurality of
tiers are configured so as to pass through the fins in a zigzag
manner. Further, the heat exchanger 68 is connected to the
compressor 64 through piping 65 or the like. In addition, the heat
exchanger 68 is connected to an indoor-side heat exchanger, an
expansion valve, and the like (not shown) so as to form a
refrigerant circuit of an air conditioner. Further, a board box 66
is arranged in the machine chamber 7. Devices mounted in the
outdoor unit are controlled by a control board 67 provided in the
board box 66.
[0060] Also in the seventh embodiment, the same advantage as that
of each of the above-mentioned corresponding first to sixth
embodiments can be obtained.
[0061] Note that, in the seventh embodiment, the outdoor unit of
the air conditioner is exemplified as an outdoor unit including an
air blower. However, the present invention is not limited thereto,
but can be implemented as, for example, an outdoor unit of a
hot-water supply device or the like. In addition, the present
invention can be widely employed as an apparatus for blowing the
air, and can be applied to an apparatus, equipment, and the like
other than the outdoor unit.
[0062] Although the details of the present invention are
specifically described above with reference to the preferred
embodiments, it is apparent that persons skilled in the art may
adopt various modifications based on the basic technical concepts
and teachings of the present invention. Note that, the present
invention is widely applicable to, for example, outdoor units of an
air blower, an air conditioner, a hot-water supply device, and the
like, and to a heat exchanger of a refrigerating cycle.
REFERENCE SIGNS LIST
[0063] 1 propeller fan, 3 boss section, 3a tubular wall, 3d outer
peripheral surface, 5 blade, 7, 107,207, 307, 407, 507 secondary
flow control slit, 51 outdoor-unit main body (casing), 61 fan motor
(driving source), 68 heat exchanger
* * * * *